Towards a bioengineered liver

Journal of Hepatology
Volume 60, Issue 2 , Pages 455-456, February 2014

Dominique Franco

Received 22 August 2013; received in revised form 12 September 2013; accepted 12 September 2013. published online 23 September 2013

COMENTARY ON:

Vascularized and functional human liver from an iPSC-derived organ bud transplant. Takebe T, Sekine K, Enomura M, Koike H, Kimura M, Ogaeri T, Zhang RR, Ueno Y, Zheng YW, Koike N, Aoyama S, Adachi Y, Taniguchi H. Nature. 2013 Jul 25;499(7459):481–4. Copyright © (2013). Abstract reprinted by permission from Macmillan Publishers Ltd.

http://www.ncbi.nlm.nih.gov/pubmed/23823721

Abstract: A critical shortage of donor organs for treating end-stage organ failure highlights the urgent need for generating organs from human induced pluripotent stem cells (iPSCs). Despite many reports describing functional cell differentiation, no studies have succeeded in generating a three-dimensional vascularized organ such as liver. Here we show the generation of vascularized and functional human liver from human iPSCs by transplantation of liver buds created in vitro (iPSC-LBs). Specified hepatic cells (immature endodermal cells destined to track the hepatic cell fate) self-organized into three-dimensional iPSC-LBs by recapitulating organogenetic interactions between endothelial and mesenchymal cells. Immunostaining and gene-expression analyses revealed a resemblance between in vitro grown iPSC-LBs and in vivo liver buds. Human vasculatures in iPSC-LB transplants became functional by connecting to the host vessels within 48hours. The formation of functional vasculatures stimulated the maturation of iPSC-LBs into tissue resembling the adult liver. Highly metabolic iPSC-derived tissue performed liver-specific functions such as protein production and human-specific drug metabolism without recipient liver replacement. Furthermore, mesenteric transplantation of iPSC-LBs rescued the drug-induced lethal liver failure model. To our knowledge, this is the first report demonstrating the generation of a functional human organ from pluripotent stem cells. Although efforts must ensue to translate these techniques to treatments for patients, this proof-of-concept demonstration of organ-bud transplantation provides a promising new approach to study regenerative medicine.

Despite agreement that portal injections of mature hepatocytes are partially effective in patients with hereditary metabolic liver diseases [1], the goal of replacing liver transplantation with this technique remains far off. Low functioning hepatocyte availability, a 50% cell loss during the procedure and difficulties in getting transplanted hepatocytes to integrate into liver plates and proliferate are the main causes of failure. The injection of stem cells rather than mature hepatocytes has given interesting results in specific rodent models [2], but there have been few trials in humans. Strategies for replacing liver transplantation have recently focused on the in vitro construction of bio-engineered livers. Decellularization-recellularization techniques have yielded liver-like transplantable organoids in small animals [3], [4]. Much remains to be done, particularly concerning the cells used for repopulation, before this complex procedure can be applied to humans.

Until recently, it was generally believed that liver organogenesis could not be reproduced in vitro, for the construction of a new liver de novo. In this study, Takabe and coworkers from Yokohama City University were able to construct a liver in a Petri dish, by culturing hepatic endoderm cells derived from human iPSCs (iPSC-HEs) with human umbilical vein endothelial cells (HUVECs) and human mesenchymal stem cells (MSCs). The cells were plated in two-dimensional conditions, but the human iPSC-HEs self-organized into macroscopically visible, mechanically stable, manipulable, three-dimensional cell clusters — iPSC-derived liver buds (iPSC-LBs) — four to eight days after seeding. In vitro, cells in human iPSC-LBs expressed early hepatic marker genes and were more functional than the hepatocyte-like cells generated from hiPSCs according to conventional procedures [5], [6]. The FGF and BMP pathways, which play key roles in organogenesis, were upregulated when iPSC-HEs were co-cultured with HUVECs and MSCs. The entire process in the Petri dish closely resembled the development in vivo of liver buds from the foregut in human and mouse embryos. Human iPSC-LBs were transplanted into ectopic sites in immunodeficient mice, in which they grew and divided. Using the cranial window model, the authors observed the development of a human vasculature within the iPSC-LBs. Human blood vessels within the transplant became patent by connecting to the vessels of the mouse host at the edge of the transplant within 48h of transplantation, resulting in a vascularized organoid. Two months later, the organoid had a vascular network, including sinusoids and hepatic cord organization with tight junctions. Most of the cells in the transplanted iPSC-LBs had developed into fully mature hepatocytes, with only a small percentage retaining fetal characteristics. Metabolic studies in mice with cranial windows or capsular iPSC-LB transplants, with drugs metabolized by different pathways in mice and humans, confirmed the appropriate functioning of transplanted human liver buds. Albumin production by hiPSC-LBs increased over time and was clearly stronger than that of human adult hepatocytes transplanted to the same sites. The functionality of a mesenteric transplant of hiPSC-LBs was further investigated in two models of acute liver failure in mice. In both models, hiPSC-LB transplantation significantly increased survival (Fig. 1).

Fig. 1. General scheme of the experiments.

This constitutes a major breakthrough in the production of bioengineered livers. For the first time, a tiny, rudimentary liver has been generated from a few cells in a Petri dish, and the transplantation of this organoid ultimately protected mice against acute liver failure. The use of stromal cells to coax iPS-HEs into appropriate differentiation appears to be the key to obtaining the correct three-dimensional organization, maturation of cells and vascularization. Of course, much remains to be done to improve bud quality before this technique could be applied in clinical practice. For example, the ultrastructural organization of the bud does not entirely reflect the lobular organization of a normal liver. There is also no development of an external bile tree, potentially resulting in the accumulation of bile acids, which might jeopardize the long-term functioning of the transplanted bud. It also remains unclear whether similar results could be obtained in larger animals. Above all, such buds cannot be transplanted orthotopically. The best indication might, therefore, be the treatment of hereditary metabolic liver diseases, in which the host liver can be left in place and a genetically corrected bud implanted in the mesentery [7]. Buds could also be used as a bridging technique in patients with cirrhosis on the waiting list for transplantation, but bud generation may take too long for use in patients with acute liver failure. In addition to potential clinical applications, this study provides important information about the types of cells most suitable for liver construction, which could be applied to the recellularization of scaffolds. This technique may also prove a formidable tool for pharmacological studies. It is just one of many new technologies emerging in medical sciences. A mixture of these techniques, undoubtedly including layer-by-layer 3D printing [8], will probably ultimately be required for the de novo bioengineering of livers.

Conflict of interest 

The author declared that he does not have anything to disclose regarding funding or conflict of interest with respect to this manuscript.

References

Source

Scientists hail breakthrough in embryonic-like stem cells

BY KATE KELLAND, HEALTH AND SCIENCE CORRESPONDENT
LONDON Thu Jan 30, 2014 1:29pm EST

A mouse embryo formed with Stimulus-Triggered Acquisition of Pluripotency (STAP) cells is seen in this undated image released by RIKEN Center for Developmental Biology on January 28, 2014.
CREDIT: REUTERS/HARUKO OBOKATA/RIKEN CENTER FOR DEVELOPMENTAL BIOLOGY/HANDOUT VIA REUTERS

(Reuters) - In experiments that could open a new era in stem cell biology, scientists have found a simple way to reprogram mature animal cells back into an embryonic-like state that allows them to generate many types of tissue.

The research, described as game-changing by experts in the field, suggests human cells could in future be reprogrammed by the same technique, offering a simpler way to replace damaged cells or grow new organs for sick and injured people.

Chris Mason, chair of regenerative medicine bioprocessing at University College London, who was not involved in the work, said its approach in mice was "the most simple, lowest-cost and quickest method" to generate so-called pluripotent cells - able to develop into many different cell types - from mature cells.

"If it works in man, this could be the game changer that ultimately makes a wide range of cell therapies available using the patient's own cells as starting material - the age of personalized medicine would have finally arrived," he said.

The experiments, reported in two papers in the journal Nature on Wednesday, involved scientists from the RIKEN Center for Developmental Biology in Japan and Brigham and Women's Hospital and Harvard Medical School in the United States.

The researchers took skin and blood cells, let them multiply, then subjected them to stress "almost to the point of death", they explained, by exposing them to various events including trauma, low oxygen levels and acidic environments.

One of these "stressful" situations was simply to bathe the cells in a weak acid solution for around 30 minutes.

Within days, the scientists found that the cells had not only survived but had also recovered by naturally reverting into a state similar to that of an embryonic stem cell.

These stem cells - dubbed Stimulus-Triggered Acquisition of Pluripotency, or STAP, cells by the researchers - were then able to differentiate and mature into different types of cells and tissue, depending on the environments they were put in.

"NEW ERA"

"If we can work out the mechanisms by which differentiation states are maintained and lost, it could open up a wide range of possibilities for new research and applications using living cells," said Haruko Obokata, who lead the work at RIKEN.

Stem cells are the body's master cells and are able to differentiate into all other types of cells. Scientists say that by helping to regenerate tissue and potentially grow new organs, they could offer ways of tackling diseases for which there are currently only limited treatments.

Recent experimental research has seen stem cells used to create a functional human liver and to create beating heart muscle tissue.

There are two main types of stem cells: embryonic ones, harvested from embryos, and adult or iPS cells, which are taken from skin or blood and reprogrammed back into stem cells.

Because the harvesting of embryonic stem cells requires the destruction of a human embryo, the technique has been the subject of ethical concerns and protests from pro-life campaigners.

Dusko Ilic, a reader in stem cell science at Kings College London, said the Nature studies described "a major scientific discovery" and predicted their findings would open "a new era in stem cell biology".

"Whether human cells would respond in a similar way to comparable environmental cues ... remains to be shown," he said in an emailed comment. "I am sure that the group is working on this and I would not be surprised if they succeed even within this calendar year."

Robin Lovell-Badge, a stem cell expert at Britain's National Institute for Medical Research, said it would be some time before the exact nature and capabilities of the STAP cells would be fully understood by scientists - and only then would their full potential in medicine become clearer.

"But the really intriguing thing to discover will be the mechanism underlying how a low pH shock triggers reprogramming," he said. "And why does it not happen when we eat lemon or vinegar, or drink cola?"

(Editing by Kevin Liffey)

Source

Human stem cell-derived hepatocytes regenerate liver function

Public release date: 26-Jul-2013
Contact: Vicki Cohn
vcohn@liebertpub.com
914-740-2100 x2156
Mary Ann Liebert, Inc./Genetic Engineering News

And extend survival in mice with hepatic failure

New Rochelle, NY, July 26, 2013 -- Researchers have generated functional hepatocytes from human stem cells, transplanted them into mice with acute liver injury, and shown the ability of these stem-cell derived human liver cells to function normally and increase survival of the treated animals. This promising advance in the development of cell-based therapies to treat liver failure resulting from injury or disease relied on the development of scalable, reproducible methods to produce stem cell-derived hepatocytes in bioreactors, as described in an article in Stem Cells and Development, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The article is available free on the Stem Cells and Development website.

Massoud Vosough and coauthors demonstrate a large-scale, integrated manufacturing strategy for generating functional hepatocytes in a single suspension culture grown in a scalable stirred bioreactor. In the article "Generation of Functional Hepatocyte-Like Cells from Human Pluripotent Stem Cells in a Scalable Suspension Culture" the authors describe the method used for scale-up, differentiation of the pluripotent stem cells into liver cells, and characterization and purification of the hepatocytes based on their physiological properties and the expression of liver cell biomarkers.

David C. Hay, MRC Centre for Regenerative Medicine, University of Edinburgh, U.K., comments on the importance of Vosough et al.'s contribution to the scientific literature in his editorial in Stem Cells and Development entitled "Rapid and Scalable Human Stem Cell Differentiation: Now in 3D." The researchers "developed a system for mass manufacture of stem cell derived hepatocytes in numbers that would be useful for clinical application," creating possibilities for future "immune matched cell based therapies," says Hay. Such approaches could be used to correct mutated genes in stem cell populations prior to differentiation and transplantation, he adds.

"The elephant in the room for stem cell therapy rarely even acknowledged let alone addressed in the literature is that of scalable production of cells for translational application," says Editor-in-Chief Graham C. Parker, PhD, research professor, Carman and Ann Adams Department of Pediatrics, Wayne State University School of Medicine. "Baharvand's groups' landmark publication not only demonstrates but exquisitely describes the methodology required to scale up stem cell populations for clinical application with a rigor to satisfy necessary manufacturing standards."

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About the Journal

Stem Cells and Development is an authoritative peer-reviewed journal published 24 times per year in print and online. The Journal is dedicated to communication and objective analysis of developments in the biology, characteristics, and therapeutic utility of stem cells, especially those of the hematopoietic system. Complete tables of content and a free sample issue may be viewed on the Stem Cells and Development website.

About the Publisher

Mary Ann Liebert, Inc., publishers is a privately held, fully integrated media company known for establishing authoritative peer-reviewed journals in many promising areas of science and biomedical research, including Cellular Reprogramming, Tissue Engineering, and Human Gene Therapy. Its biotechnology trade magazine, Genetic Engineering & Biotechnology News (GEN), was the first in its field and is today the industry's most widely read publication worldwide. A complete list of the firm's 70 journals, books, and newsmagazines is available on the Mary Ann Liebert, Inc., publishers website.

Mary Ann Liebert, Inc. 140 Huguenot St., New Rochelle, NY 10801-5215 Phone: (914) 740-2100 (800) M-LIEBERT Fax: (914) 740-2101 http://www.liebertpub.com

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Scientists create human liver from stem cells

By Kate Kelland

LONDON | Thu Jul 4, 2013 9:06am IST

LONDON (Reuters) - Scientists have for the first time created a functional human liver from stem cells derived from skin and blood and say their success points to a future where much-needed livers and other transplant organs could be made in a laboratory.

While it may take another 10 years before lab-grown livers could be used to treat patients, the Japanese scientists say they now have important proof of concept that paves the way for more ambitious organ-growing experiments.

"The promise of an off-the-shelf liver seems much closer than one could hope even a year ago," said Dusko Illic, a stem cell expert at King's College London who was not directly involved in the research but praised its success.

He said however that while the technique looks "very promising" and represents a huge step forward, "there is much unknown and it will take years before it could be applied in regenerative medicine."

Researchers around the world have been studying stem cells from various sources for more than a decade, hoping to capitalize on their ability to transform into a wide variety of other kinds of cell to treat a range of health conditions.

There are two main forms of stem cells - embryonic stem cells, which are harvested from embryos, and reprogrammed "induced pluripotent stem cells" (iPS cells), often taken from skin or blood.

Countries across the world have a critical shortage of donor organs for treating patients with liver, kidney, heart and other organ failure. Scientists are keenly aware of the need to find other ways of obtaining organs for transplant.

The Japanese team, based at the Yokohama City University Graduate School of Medicine in Japan, used iPS cells to make three different cell types that would normally combine in the natural formation of a human liver in a developing embryo - hepatic endoderm cells, mesenchymal stem cells and endothelial cells - and mixed them together to see if they would grow.

They found the cells did grow and began to form three-dimensional structures called "liver buds" - a collection of liver cells with the potential to develop into a full organ.

When they transplanted them into mice, the researchers found the human liver buds matured, the human blood vessels connected to the mouse host's blood vessels and they began to perform many of the functions of mature human liver cells.

"To our knowledge, this is the first report demonstrating the generation of a functional human organ from pluripotent stem cells," the researchers wrote in the journal Nature.

Malcolm Allison, a stem cell expert at Queen Mary University of London, who was not involved in the research, said the study's results offered "the distinct possibility of being able to create mini livers from the skin cells of a patient dying of liver failure" and transplant them to boost the failing organ.

Takanori Takebe, who led the study, told a teleconference he was so encouraged by the success of this work that he plans similar research on other organs such as the pancreas and lungs.

A team of American researchers said in April they had created a rat kidney in a lab that was able to function like a natural one, but their method used a "scaffold" structure from a kidney to build a new organ.

And in May last year, British researchers said they had turned skin cells into beating heart tissue that might one day be able to be used to treat heart failure.

That livers and other organs may one day be made from iPS cells is an "exciting" prospect, said Matthew Smalley of Cardiff University's European Cancer Stem Cell Research Institute.

"(This) study holds out real promise for a viable alternative approach to human organ transplants," he said.

Chris Mason, a regenerative medicine expert at University College London said the greatest impact of iPS cell-liver buds might be in their use in improving drug development.

"Presently to study the metabolism and toxicology of potential new drugs, human cadaveric liver cells are used, " he said. "Unfortunately these are only available in very limited quantities".

The suggestion from this new study is that mice transplanted with human iPS cell-liver buds might be used to test new drugs to see how the human liver would cope with them and whether they might have side-effects such as liver toxicity.

(This story refiles to fix a typo in the name "Yokohama" in the eighth paragraph)

(Reporting by Kate Kelland; Editing by Janet Lawrence)

Source

Also See: Scientists Fabricate Rudimentary Human Livers

Scientists Fabricate Rudimentary Human Livers

Takanori Takebe

Researchers from Japan used human stem cells to create "liver buds," rudimentary livers that, when transplanted into mice, grew and functioned.

View video here …

By GINA KOLATA

Published: July 3, 2013

Researchers in Japan have used human stem cells to create tiny human livers like those that arise early in fetal life. When the scientists transplanted the rudimentary livers into mice, the little organs grew, made human liver proteins, and metabolized drugs as human livers do.

They and others caution that these are early days and this is still very much basic research. The liver buds, as they are called, did not turn into complete livers, and the method would have to be scaled up enormously to make enough replacement liver buds to treat a patient. Even then, the investigators say, they expect to replace only 30 percent of a patient’s liver. What they are making is more like a patch than a full liver.

But the promise, in a field that has seen a great deal of dashed hopes, is immense, medical experts said.

“This is a major breakthrough of monumental significance,” said Dr. Hillel Tobias, director of transplantation at the New York University School of Medicine. Dr. Tobias is chairman of the American Liver Foundation’s national medical advisory committee.

“Very impressive,” said Eric Lagasse of the University of Pittsburgh, who studies cell transplantation and liver disease. “It’s novel and very exciting.”

The study was published on Wednesday in the journal Nature.

Although human studies are years away, said Dr. Leonard Zon, director of the stem cell research program at Boston Children’s Hospital, this, to his knowledge, is the first time anyone has used human stem cells, created from human skin cells, to make a functioning solid organ, like a liver, as opposed to bone marrow, a jellylike organ.

Ever since they discovered how to get human stem cells — first from embryos and now, more often, from skin cells — researchers have dreamed of using the cells for replacement tissues and organs. The stem cells can turn into any type of human cell, and so it seemed logical to simply turn them into liver cells, for example, and add them to livers to fill in dead or damaged areas.

But those studies did not succeed. Liver cells did not take up residence in the liver; they did not develop blood supplies or signaling systems. They were not a cure for disease.

Other researchers tried making livers or other organs by growing cells on scaffolds. But that did not work well either. Cells would fall off the scaffolds and die, and the result was never a functioning solid organ.

Researchers have made specialized human cells in petri dishes, but not three-dimensional structures, like a liver.

The investigators, led by Dr. Takanori Takebe of the Yokohama City University Graduate School of Medicine, began with human skin cells, turning them into stem cells. By adding various stimulators and drivers of cell growth, they then turned the stem cells into human liver cells and began trying to make replacement livers.

They say they stumbled upon their solution. When they grew the human liver cells in petri dishes along with blood vessel cells from human umbilical cords and human connective tissue, that mix of cells, to their surprise, spontaneously assembled itself into three-dimensional liver buds, resembling the liver at about five or six weeks of gestation in humans.

Then the researchers transplanted the liver buds into mice, putting them in two places: on the brain and into the abdomen. The brain site allowed them to watch the buds grow. The investigators covered the hole in each animal’s skull with transparent plastic, giving them a direct view of the developing liver buds. The buds grew and developed blood supplies, attaching themselves to the blood vessels of the mice.

The abdominal site allowed them to put more buds in – 12 buds in each of two places in the abdomen, compared with one bud in the brain – which let the investigators ask if the liver buds were functioning like human livers.

They were. They made human liver proteins and also metabolized drugs that human livers — but not mouse livers — metabolize.

The approach makes sense, said Kenneth Zaret, a professor of cellular and developmental biology at the University of Pennsylvania. His research helped establish that blood and connective tissue cells promote dramatic liver growth early in development and help livers establish their own blood supply. On their own, without those other types of cells, liver cells do not develop or form organs.

“They were letting nature do its thing rather than trying to conceive of what the right signals might be,” Dr. Zaret said. But, he said, the mice were studied for only a couple of months. He would like to see what happens over a longer time.

“We don’t know if the cells will grow out of control or will poop out,” Dr. Zaret said.

Even if the liver buds never fulfill their clinical promise, they still could be enormously important for pharmaceutical research, Dr. Zon said. Drugs must be tested to see if they damage the liver, a major site of drug toxicity. Companies do this with liver cells taken from cadavers and grown in petri dishes. But the liver buds could be a big improvement and offer a large supply of rudimentary livers for testing.

“That would be huge,” Dr. Zon said. “It would open up lots of drugs in the pipeline and bring them to the clinic much more quickly.”

Dr. Takebe and his colleagues, though, are more focused on scaling up their process so they can think of trying to take it to the clinic, perhaps to treat babies and children whose livers have failed. Dr. Takebe estimates they would need hundreds of thousands, perhaps millions, of liver buds to replace 30 percent of the liver.

Dr. Tobias, the transplant surgeon, hopes they succeed.

“This is obviously the wave of the future,” he said.

Source

Novel Liver Stem Cell Model Could Speed Up Process for Developing New Drugs

In the latest issue of STEM CELLS Translational Medicine, a research team reports a new method which involves the creation of a highly stable and sensitive liver stem cell model.

Durham, NC (PRWEB) June 11, 2013

The path to bringing a new drug to market is, simply put, a rocky one. Not only is it estimated to take over 12 years at an average price tag running anywhere between US $800 million and US $2 billion, but more often than not the new drug never makes it through the process.

But now a research team reports that it has developed a way to speed up the process. Their work, which involves the creation of a highly stable and sensitive liver stem cell model, is reported in the latest issue of STEM CELLS Translational Medicine.

“Liver toxicity is the second most common cause of human drug failure,” explained David Hay, Ph.D., of the University of Edinburgh’s MRC Centre for Regenerative Medicine, who led the team made up of university colleagues and scientists from Bristol-Myers Squibb, Princeton, N.J. “But one major bottleneck in safety testing new drugs has been finding a routine supply of good quality primary human hepatocytes from the desired genetic background.”

Scientists have long believed that finding an efficient way to force pluripotent stem cells (PSCs) to develop into hepatocytes — liver cells — could be the way around the problem. “But faithfully recapitulating human physiology in a dish from a renewable source remains a holy grail for medicine and the pharmaceutical industry,” Dr. Hay noted.

“Many procedures have been described that, to a limited extent, exhibit human-tissue-specific function in vitro but incomplete cellular differentiation and/or the loss of cell phenotype after they differentiate. Using our knowledge in pharmacology, stem cell biology and materials chemistry, we developed a highly stable and sensitive model.”

Their method involved expanding PSCs and driving their differentiation to hepatocytes, then replating them onto a synthetic surface. The results yielded active cell populations that displayed stable function for over two weeks in vitro.

“The scalable nature of our model combined with the interchangeable genetic element demonstrates clear advantages over the erratic supply of highly variable human hepatocytes from deceased specimens,” Dr. Hay added. “We believe our approach is important and will likely contribute to improvements in drug safety testing.”

“This model was compared to human liver cells from deceased donors and found to be equivalent, suggesting that stem cell-derived hepatocyles have potential to improve the preclinical assessment of human liver toxicity,” said Anthony Atala, M.D., Editor of STEM CELLS Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine. “

The full article, “Developing high fidelity hepatotoxicity models from pluripotent stem cells,” can be accessed at http://www.stemcellstm.com.

About STEM CELLS Translational Medicine: STEM CELLS TRANSLATIONAL MEDICINE (SCTM), published by AlphaMed Press, is a monthly peer-reviewed publication dedicated to significantly advancing the clinical utilization of stem cell molecular and cellular biology. By bridging stem cell research and clinical trials, SCTM will help move applications of these critical investigations closer to accepted best practices.

About AlphaMed Press: Established in 1983, AlphaMed Press with offices in Durham, NC, San Francisco, CA, and Belfast, Northern Ireland, publishes two other internationally renowned peer-reviewed journals: STEM CELLS® (http://www.StemCells.com), celebrating its 31st anniversary in 2013, is the world's first journal devoted to this fast paced field of research. The Oncologist® (http://www.TheOncologist.com), also a monthly peer-reviewed publication, entering its 18th year, is devoted to community and hospital-based oncologists and physicians entrusted with cancer patient care. All three journals are premier periodicals with globally recognized editorial boards dedicated to advancing knowledge and education in their focused disciplines.

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New Liver Cell for Cellular Therapy to Aid in Liver Regeneration

Provided by ScienceDaily

June 6, 2013 — Liver transplantation is the mainstay of treatment for patients with end-stage liver disease, the 12th leading cause of death in the United States, but new research from the Icahn School of Medicine at Mount Sinai, published in the journal Cell Stem Cell today, suggests that it may one day become possible to regenerate a liver using cell therapy in patients with liver disease. Investigators discovered that a human embryonic stem cell can be differentiated into a previously unknown liver progenitor cell, an early offspring of a stem cell, and produce mature and functional liver cells.

"The discovery of the novel progenitor represents a fundamental advance in this field and potentially to the liver regeneration field using cell therapy," said the study's senior author, Valerie Gouon-Evans, PharmD, PhD, Assistant Professor, in the Department of Developmental and Regenerative Biology, Black Family Stem Cell Institute, at the Icahn School of Medicine at Mount Sinai. "Until now, liver transplantation has been the most successful treatment for people with liver failure, but we have a drastic shortage of organs. This discovery may help circumvent that problem."

In conjunction with the laboratory of Matthew J. Evans, PhD, from the Department of Microbiology at Icahn School of Medicine at Mount Sinai, investigators demonstrated the functionality of the liver cells generated from the progenitors, as the liver cells can be infected by the hepatitis C virus, a property restricted to liver cells exclusively.

A critical discovery in this research was finding that the novel progenitor has a receptor protein on its cell surface called KDR, or vascular endothelial growth factor receptor 2, which until now, was thought to be restricted to endothelial cells that form vessels, the progenitors for endothelial cells and the progenitors blood cells. The research team showed that activation of KDR on these novel liver progenitors differentiates them into mature liver cells. Additionally, work in a mouse model revealed similar cells, indicating that the progenitors are conserved from mouse to human, and therefore, they must be "important cells with promising potential for cell therapy in treating liver disease," explained Dr. Gouon-Evans.

Next, the research team will examine specifically whether these liver cells obtained from human embryonic stem cells in a dish help repair injured livers in preclinical animal models of liver disease.

Funding for this study was provided by The Black Family Stem Cell Institute, the National Institute of Diabetes and Digestive and Kidney Diseases, the Robin Chemers Neustein Postdoctoral Fellowship, the American Cancer Society, and Pew Charitable Funds.

About The Black Family Stem Cell Institute The Black Family Stem Cell Institute is Mount Sinai's foundation for both basic and disease-oriented research on embryonic and adult stem cells. The therapeutic use of stem cells is a promising area of medicine for the decades ahead and researchers are examining why stem cells function in certain types of niches, microenvironments, and pockets of activity. Investigators are working to break the code in stem cell communication by determining how stem cells signal one another and other cells. The new knowledge that will result from this research holds the promise of diagnostic and therapeutic breakthroughs.

Studies show that it is possible to reprogram adult skin cells into cells that are very similar to embryonic stem cells. Once stem cells can be grown and differentiated in a controlled way to replace degenerated cells and repair tissues, medical science may then be able to diagnose and cure many intractable diseases at their earliest stages, such as type 1 diabetes, Parkinson's disease, various cardiovascular diseases, liver disease, and cancer.

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Story Source:

The above story is reprinted from materials provided by The Mount Sinai Hospital / Mount Sinai School of Medicine, via Newswise.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Orit Goldman, Songyan Han, Marion Sourrisseau, Noelle Dziedzic, Wissam Hamou, Barbara Corneo, Sunita D’Souza, Thomas Sato, Darrell N. Kotton, Karl-Dimiter Bissig, Tamara Kalir, Adam Jacobs, Todd Evans, Matthew J. Evans, Valerie Gouon-Evans. KDR Identifies a Conserved Human and Murine Hepatic Progenitor and Instructs Early Liver Development. Cell Stem Cell, 2013; 12 (6): 748 DOI: 10.1016/j.stem.2013.04.026

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Early Results Show Promise for Stem Cells in Treating Chronic Liver Failure

Stem cell transfusions may someday replace the need for transplants in patients who suffer from liver failure caused by hepatitis B, according to a new study coming out of Beijing. . The results are published in the October issue of STEM CELLS Translational Medicine. Worldwide more than 500,000 people die each year from this condition.

Durham, NC (PRWEB) October 11, 2012

Stem cell transfusions may someday replace the need for transplants in patients who suffer from liver failure caused by hepatitis B, according to a new study coming out of Beijing. . The results are published in the October issue of STEM CELLS Translational Medicine. Worldwide more than 500,000 people die each year from this condition.

“In China, hepatitis B virus (HBV) infection accounts for the highest proportion of liver failure cases. While liver transplantation is considered the standard treatment, it has several drawbacks including a limited number of donors, long waiting lists, high cost and multiple complications. Our study shows that mesenchymal stem cell (MSCs) transfusions might be a good, safe alternative,” said Fu-Sheng Wang, Ph.D., M.D., the study’s lead author and director of the Research Center for Biological Therapy (RCBT) in Beijing.

Wang along with RCBT colleague, Drs. Ming Shi and Zheng Zhang of the Research Center for Biological Therapy, The Institute of Translational Hepatology led the group of physician-scientists from the centers and Beijing 302 Hospital who conducted the study.

MSC transfusions had already been shown to improve liver function in patients with end-stage liver diseases. This time, the researchers wanted to gauge the safety and initial efficacy of treating acute-on-chronic liver failure (ACLF) with MSCs. The American Association for the Study of Liver Diseases and the European Association for the Study of the Liver define ACLF as an “acute deterioration of pre-existing chronic liver disease usually related to a precipitating event and associated with increased mortality at three months due to multisystem organ failure.” The short-term mortality rate for this condition is more than 50 percent.

MSCs have self-renewing abilities and the potential to differentiate into various types of cells. More importantly, they can interact with immune cells and cause the immune system to adjust to the desired level.

Of the 43 patients in this pilot study — each of whom had liver failure resulting from chronic HBV infection — 24 were treated with MSCs taken from donated umbilical cords and 19 were treated with saline as the control group. All received conventional therapy as well. The liver function, adverse events and survival rates were then evaluated during the 48-week or 72-week follow-up period.

Along with increased survival rates, the patients’ liver function improved and platelet count increased. No significant side effects were observed throughout the treatment and follow-up period.

“While the results are preliminary and this pilot study includes a small number of patients, MSC transfusions appear to be safe and may serve as a novel therapeutic approach for HBV-associated ACLF patients,” Dr. Shi said.

“The study also highlights several key issues that will need to be considered in the design of future clinical studies, such as the optimal type of stem cells that will be infused, the minimum effective number of the cells and the best route of administration,” Dr. Wang added.

“These results are certainly promising and the strategy merits additional study, especially considering the shortage of donor organs” said Anthony Atala, MD, Editor of STEM CELLS Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine.

###

The full article, “Human mesenchymal stem cell transfusion is safe and improves liver function in acute-on-chronic liver failure patients,” can be accessed at: http://www.stemcellstm.com/.

About STEM CELLS Translational Medicine: STEM CELLS TRANSLATIONAL MEDICINE (SCTM), published by AlphaMed Press, is a monthly peer-reviewed publication dedicated to significantly advancing the clinical utilization of stem cell molecular and cellular biology. By bridging stem cell research and clinical trials, SCTM will help move applications of these critical investigations closer to accepted best practices.

About AlphaMed Press: Established in 1983, AlphaMed Press with offices in Durham, NC, San Francisco, CA, and Belfast, Northern Ireland, publishes two other internationally renowned peer-reviewed journals: STEM CELLS® (http://www.StemCells.com), celebrating its 30th anniversary in 2012, is the world's first journal devoted to this fast paced field of research. The Oncologist® (http://www.TheOncologist.com), also a monthly peer-reviewed publication, entering its 17th year, is devoted to community and hospital-based oncologists and physicians entrusted with cancer patient care. All three journals are premier periodicals with globally recognized editorial boards dedicated to advancing knowledge and education in their focused disciplines.

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Proteonomix Announces Agreement with the University of Medicine and Dentistry of New Jersey (UMDNJ) to Conduct a Phase 1 Trial with UMK-121 in End-Stage Liver Disease

PRESS RELEASE

Sept. 14, 2012, 9:00 a.m. EDT

Preeminent Liver Expert Dr. Baburao Koneru to Serve as Principal Investigator

PARAMUS, N.J., Sep 14, 2012 (BUSINESS WIRE) -- Proteonomix, Inc. (otc/bb:PROT), a biotechnology company focused on developing therapeutics based upon the use of human cells and their derivatives, today announced it has entered into an agreement with Piscataway, N.J.-based University of Medicine and Dentistry of New Jersey (UMDNJ) to conducted a Phase 1 clinical trial with its proprietary, patent-pending mobilization technology UMK-121 in patients with end-stage liver disease (ESLD). The Company also announced that Chief Executive Officer Michael Cohen made a presentation at the National Investment Banking Association's (NIBA) 123rd Investment Conference yesterday at the New York Marriott Downtown in New York City.

The single-center Phase 1 clinical trial, Mobilization of Stem Cells with UMK 121 in Patients with Cirrhosis, will enroll 15 patients with ESLD. The trial will study the safety of mobilization of stem cells in this patient population, as well as the effects of mobilization of stems cells from bone marrow to the peripheral circulation on liver function. Baburao Koneru, M.D., Professor and Chief of the Division of Transplant and Hepatobiliary Surgery at New Jersey Medical School, will serve as the trial's principal investigator.

"We are extremely pleased to announce that our trial will be conducted at this highly respected institution under the direction of Dr. Koneru, who is a renowned expert in the field of liver function," said Mr. Cohen. "Our presentation to the investment professionals attending the NIBA conference provided an opportunity to discuss the potential of UMK-121 in ESLD as we make preparations to commence this clinical trial, which we hope to initiate in the coming months."

UMK-121 combines two existing FDA-approved drugs with the intention of mobilizing mesenchymal stem cells from bone marrow to the peripheral circulation. This proprietary drug combination is designed to reduce inflammation and increase angiogenesis to restore liver function, potentially extending the life of ESLD patients awaiting liver transplant.

About the University of Medicine and Dentistry of New Jersey

The University of Medicine and Dentistry of New Jersey (UMDNJ) is New Jersey's only health sciences university with more than 6,000 students on five campuses attending three medical schools, the State's only dental school, a graduate school of biomedical sciences, a school of health related professions, a school of nursing and New Jersey's only school of public health. UMDNJ operates University Hospital, a Level I Trauma Center in Newark, and University Behavioral HealthCare, which provides a continuum of healthcare services with multiple locations throughout the State.

About National Investment Banking Association (NIBA)

NIBA is the only national not-for-profit trade association of regional and independent brokerages, investment banking firms, institutional investors and related capital market service providers. Since its inception, NIBA member firms have successfully completed more than 1,000 equity offerings totaling approximately $10 billion in new capital. The member firms of NIBA represent more than 8,000 registered representatives with an estimated $78 billion in assets under management, and are responsible for 90% of all Initial Public Offerings under $20 million. For more information, please visit www.nibanet.org .

About Proteonomix, Inc.

Proteonomix is a biotechnology company focused on developing therapeutics based upon the use of human cells and their derivatives. The Proteonomix family of companies includes Proteoderm, StromaCel, PRTMI and THOR Biopharma. Proteoderm is a wholly owned subsidiary that has developed an anti-aging line of skin care products. StromaCel develops therapeutic modalities for the treatment of cardiovascular disease and plans to file an IND application for treatment of patients who have suffered post-myocardial infarction. Proteonomix Regenerative Translational Medicine Institute, Inc. (PRTMI) intends to focus on the translation of promising research in stem cell biology and cellular therapy to clinical applications of regenerative medicine. Additional information is available at www.proteonomix.com and www.proteoderm.com .

Certain statements contained herein are "forward-looking statements" (as defined in the Private Securities Litigation Reform Act of 1995). Proteonomix, Inc. cautions that statements made in this press release constitute forward-looking statements and makes no guarantee of future performance. Actual results or developments may differ materially from projections. Forward-looking statements are based on estimates and opinions of management at the time statements are made.

SOURCE: Proteonomix, Inc.

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Stem cells vs. HIV

Provided by ScienceBlog.com

Posted May 2, 2012

UC Davis Health System researchers are a step closer to launching human clinical trials involving the use of an innovative stem cell therapy to fight the virus that causes AIDS.

In a paper published in the May issue of the Journal of Virology, the UC Davis HIV team demonstrated both the safety and efficacy of transplanting anti-HIV stem cells into mice that represent models of infected patients. The technique, which involves replacing the immune system with stem cells engineered with a triple combination of HIV-resistant genes, proved capable of replicating a normally functioning human immune system by protecting and expanding HIV-resistant immune cells. The cells thrived and self-renewed even when challenged with an HIV viral load.

“We envision this as a potential functional cure for patients infected with HIV, giving them the ability to maintain a normal immune system through genetic resistance,” said lead author Joseph Anderson, an assistant adjunct professor of internal medicine and a stem cell researcher at the UC Davis Institute for Regenerative Cures. “Ideally, it would be a one-time treatment through which stem cells express HIV-resistant genes, which in turn generate an entire HIV-resistant immune system.”

To establish immunity in mice whose immune systems paralleled those of patients with HIV, Anderson and his team genetically modified human blood stem cells, which are responsible for producing the various types of immune cells in the body.

Building on work that members of the team have pursued over the last decade, they developed several anti-HIV genes that were inserted into blood stem cells using standard gene-therapy techniques and viral vectors (viruses that efficiently insert the genes they carry into host cells). The resulting combination vector contained:

• a human/rhesus macaque TRIM5 isoform, which disrupts HIV from uncoating in the cytoplasm
• a CCR5 short hairpin RNA (shRNA), which prevents certain strains of HIV from attaching to target cells
• a TAR decoy, which stops HIV genes from being expressed inside of the cell by soaking up a critical protein needed for HIV gene expression

These engineered blood stem cells, which could be differentiated into normal and functional human immune cells, were introduced into the mice. The goal was to validate whether this experimental treatment would result in an immune system that remained functional, even in the face of an HIV infection, and would halt or slow the progression toward AIDS.

The results were successful on all counts.

“After we challenged transplanted mice with live HIV, we demonstrated that the cells with HIV-resistant genes were protected from infection and survived in the face of a viral challenge, maintaining normal human CD4 levels,” said Anderson.
CD4+ T-cells are a type of specialized immune cell that HIV attacks and uses to make more copies of HIV.

“We actually saw an expansion of resistant cells after the viral challenge, because other cells which were not resistant were being killed off, and only the resistant cells remained, which took over the immune system and maintained normal CD4 levels,” added Anderson.

The data provided from the study confirm the safety and efficacy of this combination anti-HIV lentiviral vector in a hematopoietic stem cell gene therapy setting for HIV and validated its potential application in future human clinical trials. The team has submitted a grant application for human clinical trials and is currently seeking regulatory approval, which is necessary to move on to clinical trials.

“This research represents an important step in our fight against HIV/AIDS,” said Richard Pollard, chief of infectious diseases at UC Davis and one of the study’s co-authors. “Clinical trials could give us the critical information we need to determine whether our approach truly represents a functional cure for a terrible disease that has affected millions and millions of people.”

The study was supported by UC Davis Health System start-up funds from the Dean’s office for the Stem Cell Program and by the James B. Pendleton Charitable Trust. This work was also supported in part by the Gin and Imy Mar stem cell research fund.

Other authors were Rachel X. Chen, Jon E. Walker, Jeannine McGee, Catherine Nacey, Richard B. Pollard, Mehrdad Abedi, Gerhard Bauer, and Jan A. Nolta, all affiliated with the UC Davis Institute of Regenerative Cures.

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Teaching old cells new tricks

Stem cells. Credit: Candy Cho

April 25, 2012 in Medical research

Much hyped by the media, stem cells have tremendous power to improve human health. As part of the Cambridge Stem Cell Initiative, Dr Ludovic Vallier’s research in the Anne McLaren Laboratory for Regenerative Medicine shows how stem cells can further our understanding of disease and help deliver much-needed new treatments.

How do you study a human disease that has no equivalent in animals and where the human cells in question are so hard to grow outside the body they cannot be tested in the laboratory? The answer, until now, was with great difficulty. But by using a new stem cell technique, that is set to change.

Dr. Ludovic Vallier, who holds an MRC Senior Fellowship in the Anne McLaren Laboratory for Regenerative Medicine, Department of Surgery at Cambridge in collaboration with Professor David Lomas (Cambridge Institute for Medical Research and Department of Medicine), works on a group of devastating genetic diseases affecting the liver.

“We target metabolic diseases of the liver, diseases such as alpha 1 antitrypsin deficiency. It’s one of the most common single genetic disorders and the protein it affects – which is only produced by the liver – is really important because it controls activity of elastase in the lung. Without this control, people develop serious lung problems and the disease also affects the liver, so these patients develop liver failure,” he explained.

The problem is that these diseases cannot be studied in vitro – in a dish – in the laboratory, he said: “You can’t take cells from the liver of these very sick patients, and if you could they wouldn’t grow, which means you don’t have any way of screening drugs that could help treat these diseases.”

Without effective drugs, the only current treatment is a liver transplant. “There is a huge shortage of organs and transplantation involves taking immunosuppressive drugs, which is heavy treatment especially in already fragile patients,” Dr. Vallier said. “And the disease is progressive so it’s very complicated to manage.” Understandably, Dr. Vallier is excited that a new method of producing stem cells developed in Japan has given him and other researchers a way of studying these diseases and screening potential drugs to treat them.

“The new technology consists of taking cells from skin and reprogramming them so that they become stem cells – cells that are capable of proliferating and differentiating into almost all tissue types,” he said.

This reprogramming means a cell with a previously fixed identity can be taught a new one – in this case taking skin cells and reprogramming them to become liver cells. When the skin cells come from a patient with liver disease, these skin-turned-liver cells also have the disease, making them ideal for studying the disease and screening potential drugs to treat it.

According to Dr. Vallier: “Because we can generate liver cells that mimic the disease of the original patient in vitro, that allows us to do basic studies that were impossible by biopsy or primary culture and also to do drug screening.” And because the skin cells can come from a whole range of people, it gives researchers access to a broad diversity of patients as well as overcoming some of the ethical concerns associated with embryonic stem cells.

“That’s a very important step because it solves the problems associated with a limited stock of stem cells,” he said, “and because it’s a simple method, it’s easily accessible to a wide number of laboratories.”

Showing this can be done in a small number of liver patients in Cambridge is an important proof of concept, and supports the possibility that a similar approach might be applicable to a wide range of other serious diseases that still lack effective treatments, including neurodegenerative diseases such as Parkinson’s and Alzheimer’s Disease as well as heart diseases.

And Cambridge – which now has almost 30 groups doing stem cell research and strong links between academic researchers and clinicians – is perfectly positioned to make the most of this new technique.

“The Laboratory for Regenerative Medicine is starting to become an expert in this disease modelling and we are all part of a larger consortium, the Cambridge Stem Cell Initiative (SCI),” said Dr. Vallier. “Together, we are putting together resources and scientific interest to really develop stem cells and their clinical application. The SCI is a unique consortium because it brings together a wealth of complementary expertise.”

While this first revolution involves in vitro disease modelling and drug screening, Dr. Vallier hopes this work will ultimately lead to personalized cell-based therapies where liver cells reprogrammed from a patient’s own skin cells could be used in place of a liver transplant. “It will take time for us to assess this clinical use and show that it is safe as well as effective,” he explained, “but if you ask me again in five years I should be able to tell you whether we are going to do it.”

Provided by University of Cambridge (news : web)

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EASL 2012: Gallbladder shown as potential stem cell source for regenerative liver and metabolic disease

Posted On: April 19, 2012 - 9:31am

A new study presented today at the International Liver Congress™ 2012 indicates the potential for gallbladder tissue (which is routinely discarded from organ donors and surgical interventions) to be a highly available candidate source for multipotential stem cells.(1)

Biliary tree stem/progenitor cells (BTSCs) have previously been identified in the glands of normal adult human extrahepatic bile ducts and been shown to generate in vitro and in vivo mature cells of the hepato-biliary and pancreatic endocrine lineages.

The study found both normal and pathological gallbladders contained easily isolable cells with the phenotype and biological properties of BTSCs. Interestingly, in an animal model, these cells were able to repopulate the injured liver and to improve synthetic functions.

These data open novel perspectives for the collection and use of multipotent stem cells in regenerative therapies of liver, bile duct, and pancreatic diseases including diabetes

Source: European Association for the Study of the Liver

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UCLA-engineered stem cells seek out and kill HIV in living organisms

HIV virus

By Enrique Rivero April 12, 2012

Expanding on previous research providing proof-of-principle that human stem cells can be genetically engineered into HIV-fighting cells, a team of UCLA researchers have now demonstrated that these cells can actually attack HIV-infected cells in a living organism.

The study, published April 12 in the journal PLoS Pathogens, demonstrates for the first time that engineering stem cells to form immune cells that target HIV is effective in suppressing the virus in living tissues in an animal model, said lead investigator Scott G. Kitchen, an assistant professor of medicine in the division of hematology and oncology at the David Geffen School of Medicine at UCLA and a member of the UCLA AIDS Institute.

"We believe that this study lays the groundwork for the potential use of this type of an approach in combating HIV infection in infected individuals, in hopes of eradicating the virus from the body," he said.

In the previous research, the scientists took CD8 cytotoxic T lymphocytes — the "killer" T cells that help fight infection — from an HIV-infected individual and identified the molecule known as the T cell receptor, which guides the T cell in recognizing and killing HIV-infected cells. However, these T cells, while able to destroy HIV-infected cells, do not exist in great enough quantities to clear the virus from the body. So the researchers cloned the receptor and used this to genetically engineer human blood stem cells. They then placed the engineered stem cells into human thymus tissue that had been implanted in mice, allowing them to study the reaction in a living organism.

The engineered stem cells developed into a large population of mature, multi-functional HIV-specific CD8 cells that could specifically target cells containing HIV proteins. The researchers also discovered that HIV-specific T cell receptors have to be matched to an individual in much the same way an organ is matched to a transplant patient.

In this current study, the researchers similarly engineered human blood stem cells and found that they can form mature T cells that can attack HIV in tissues where the virus resides and replicates. They did so by using a surrogate model, the humanized mouse, in which HIV infection closely resembles the disease and its progression in humans.

In a series of tests on the mice's peripheral blood, plasma and organs conducted two weeks and six weeks after introducing the engineered cells, the researchers found that the number of CD4 "helper" T cells — which become depleted as a result of HIV infection — increased, while levels of HIV in the blood decreased. CD4 cells are white blood cells that are an important component of the immune system, helping to fight off infections. These results indicated that the engineered cells were capable of developing and migrating to the organs to fight infection there.

The researchers did note a potential weakness with the study: Human immune cells reconstituted at a lower level in the humanized mice than they would in humans, and as a result, the mice's immune systems were mostly, though not completely, reconstructed. Because of this, HIV may be slower to mutate in the mice than in human hosts. So the use of multiple, engineered T cell receptors may be one way to adjust for the higher potential for HIV mutation in humans.

"We believe that this is the first step in developing a more aggressive approach in correcting the defects in the human T cell responses that allow HIV to persist in infected people," Kitchen said.

The researchers will now begin making T cell receptors that target different parts of HIV and that could be used in more genetically matched individuals, he said.

Other study authors are Bernard R. Levin, Gregory Bristol, Valerie Rezek, Sohn Kim, Christian Aguilera-Sandoval, Arumugam Balamurugan, Otto O. Yang and Jerome A. Zack, all of UCLA.

The National Institutes of Health, the California HIV/AIDS Research Program, the California Institute for Regenerative Medicine, the UC Multicampus Research Program and Initiatives from the California Center for Antiviral Drug Discovery, and the UCLA Center for AIDS Research (CFAR) funded this study.

The UCLA AIDS Institute, established in 1992, is a multidisciplinary think tank drawing on the skills of top-flight researchers in the worldwide fight against HIV and AIDS, the first cases of which were reported in 1981 by UCLA physicians. Institute members include researchers in virology and immunology, genetics, cancer, neurology, ophthalmology, epidemiology, social sciences, public health, nursing and disease prevention. Their findings have led to advances in treating HIV, as well as other diseases, such as hepatitis B and C, influenza and cancer.

For more news, visit the UCLA Newsroom and follow us on Twitter.

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Turning Lymph Nodes Into Liver-Growing Factories

If your liver fails, having 40 small but functional livers scattered around your body might be the next best thing.

by Adam Piore

From the March 2012 issue; published online April 11, 2012

For people suffering from advanced liver disease, the prognosis is bleak. In many patients, such as those with cirrhosis, the liver becomes so clogged with scar tissue that healthy cells are choked off, preventing it from fulfilling its role of filtering toxins. The only cure is a liver transplant. Yet with just 6,000 available organs for some 100,000 patients each year, chances of winning the liver lottery are slim. And if you’re elderly or suffering from another disease, the chances are closer to zero.

But a surprising new technique under development by University of Pittsburgh stem cell researcher Eric Lagasse may radically improve those odds. Lagasse, based at Pitt’s McGowan Institute for Regenerative Medicine, has discovered how to turn any one of the body’s 500 lymph nodes—the small, oval-shaped organs where immune cells gather to fight invading pathogens—into an incubator that can grow an entirely new liver. Creating a whole set of miniature new livers might take as little as obtaining liver cells from healthy donors and placing them inside the lymph nodes of patients suffering from liver disease.

The concept was born in 2007, while Lagasse was pondering how to overcome a major roadblock to liver regeneration—in those with liver disease, the organ forms scar tissue that destroys its ability to heal. But then he noticed emerging evidence that transplanted liver cells could survive in unusual areas of the body, for instance under the renal capsule, a fibrous layer that protects the kidney from trauma. Lagasse reasoned that if he could implant liver cells away from the diseased organ, instead of succumbing they just might multiply and thrive.

So he set to work trying to grow liver cells outside the dying organ. As his test tube, he used mice with end-stage liver disease, implanting liver cells, or hepatocytes, from another mouse into their kidney capsules, under the skin, and into the spleen. Most of the mice died within eight weeks, the usual prognosis for end-stage liver failure in mice. But that changed when Lagasse injected cells into the belly: The mice gained weight, recovered energy, and within weeks appeared healthy.

After watching those mice thrive for several months, Lagasse repeated the experiment using fluorescent markers to trace the path of the liver cells. To his surprise, they had migrated to lymph nodes, where they grew to form large nodules that, in aggregate, reached a mass capable of keeping the animal alive.

It actually made sense. In many ways, lymph nodes are ideal bioreactors for growing new livers. They have an unusual capacity to expand, allowing them to accommodate an entire organ. They have ready access to the bloodstream, which nurtures new cells with nutrients as well as hormones and signaling agents needed for growth. And since the body has many lymph nodes, some can sacrifice their traditional duties to grow livers. The injections were so successful, Lagasse realized, because the belly provided enough space for cells to migrate.

Further experimentation showed Lagasse that if he injected hepatocytes directly into the lymph nodes, the cells picked up signaling proteins (essentially SOS signals to grow) released into the bloodstream from the dying liver. “There is communication between the new and a diseased liver,” Lagasse says. “They share some functions. We don’t totally understand the signaling mechanism, but we don’t need to if it works.”

Using his technique in mice, Lagasse has already succeeded in growing 20 to 40 small livers that gradually pick up the slack as the central liver fades. Together the mini-livers add up to 70 percent the size of a normal liver.

So far, Lagasse has not seen adverse reactions in his experimental mice. Rejection is not a problem because the animals were genetically engineered to share identical DNA, eliminating the risk that the immune system would attack foreign hepatocytes. In humans, Lagasse is banking on immunosuppressant drugs to prevent rejection. Further ahead, he is looking to an emerging technology known as induced pluripotent stem cells (iPSCs), in which adult cells are reprogrammed to be like embryonic stem cells so they can transform into any type of cell. Doctors could then collect blood or skin cells from a patient and turn them into healthy liver cells, enabling patients to be their own donors.

Even if rejection can be controlled, patients gravely ill from end-stage liver disease might succumb to surgery itself. To address this, Lagasse has injected hepatocytes into lymph nodes in peripheral parts of a mouse’s body—under the knee or arm—because that requires less invasive surgery. Growing a liver behind a knee is not ideal; in humans it might cause a bump weighing more than a pound in an inconvenient spot. But cultivating a liver in these peripheral areas could allow a very sick patient to survive long enough to recover the strength to undergo implantation in a more practical location.

Next Lagasse plans to replicate his experiments in pigs and hopes to implant human patients within the next few years. In principle, there’s no reason the approach should be limited to livers. “We’re talking about bioreactors that could grow any number of tissues inside the body,” Lagasse says. “This could work for any organ that secretes things or produces cells.” The thymus and pancreatic cells may be future candidates.

Stem cell expert Robert Lanza, who heads scientific research at Advanced Cell Technology in Massachusetts, calls the research an “exciting, novel idea.” But he sounds notes of caution. Liver cells carry out hundreds of different functions, only some of which Lagasse has tested in mice, and it is unlikely that transplanted cells could fulfill all of them in humans. “Also, you can envision all sorts of locations where it would not be good to have these cells,” he says. “What if they migrate to the lungs or brain?”

Lagasse concedes the many hurdles that lie ahead, not the least of which is convincing people that his bizarre transplantation technique might work. “This is such a wild idea, we need to demonstrate it could actually be used on a patient,” Lagasse says. “Still, I’ve spoken to many surgeons who are very excited about it.”

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STEM-CELL JAB MAY SAVE LIVER VICTIMS

Professor Anil Dhawan, who is leading the trial at London’s King’s College Hospital

Sunday April 8,2012

By Lucy Johnston

AS BRITAIN faces an epidemic of liver disease a medical breakthrough is offering new hope to those awaiting transplants.

There is an acute shortage of donor organs but doctors believe they can repair damaged livers by injecting specially treated cells into them.

Trials of the new stem-cell treatment are to begin on ­children with rare and deadly liver conditions. If they are successful, patients with livers damaged by alcohol, obesity or illness could also be saved.

Large numbers of liver patients die each year while waiting for a transplant. Some don’t even make the transplant list due to organ shortages.

The death toll due to liver disease has risen by a quarter in the last decade. Just over 11,500 men and women now die of liver disease every year, up from 9,200 in 2001.

It is estimated just under 80 per cent of these deaths are caused by alcohol, 10 to 15 per cent by obesity and the remainder by hepatitis or inherited conditions. The most recent figures show that about 150 of 700 organs transplanted each year go to recovering alcoholics.

“We have many very sick children and babies who need transplants” Professor Anil Dhawan

Professor Anil Dhawan who is leading the trial at London’s King’s College Hospital, described the use of stem cells to treat liver disease as an “exciting breakthrough”.

He said: “We have many very sick children and babies who need transplants. If we can cure them without a transplant it will be a ­fantastic development.”

Professor Etienne Sokal, who developed the technique at the Catholic University of Louvain in Belgium, said: “Some patients with liver disease are unable to produce appropriate stem cells to repair the liver. The cells we infuse into the liver supply the liver with new stem cells, which are able to correct the missing functions.”

The stem cells, taken from the organs of dead donors are better tolerated than a transplant and require fewer drugs to reduce the risks of the body rejecting them.

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Artificial liver cells win their creator prize for their potential to reduce animal experiments

Top images diseased liver cells, bottom images healthy liver cells. Credit: Tamir-Rashid

February 29, 2012

Cambridge research that created liver cells from stem cells has today been recognised with a national prize by the National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs).

Producing liver cells that demonstrate inherited liver diseases from human skin cells has earned Dr. Ludovic Vallier from the University of Cambridge a major prize from the National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs). These cells, known as human induced pluripotent stem cells (hIPSCs), have already attracted attention for the possibilities they offer to regenerate damaged tissues and organs. But it is their potential to reduce the number of animals used for screening potential drug treatments that led to Dr. Vallier receiving the Centre’s 3Rs prize for 2011.

The prize, sponsored by GlaxoSmithKline, of a £2,000 personal award and a £18,000 research grant, is for the scientific paper published in the last three years that contributes most to the advancement of the 3Rs (Replacement, Reduction and Refinement). Dr Vallier’s winning paper was published in The Journal of Clinical Investigation in 2010. He received his prize from Professor Paul Matthews OBE of GlaxoSmithKline at the NC3Rs Annual Science Review Meeting in London on 28 February.

Human liver cells (hepatocytes) cannot be grown in the laboratory and differences between rodents and humans mean that it is rarely possible to recreate the human disease completely in mice or rats or to use cultures of rat or mouse liver cells. Dr Vallier’s team took skin cells (dermal fibroblasts) from seven patients with a variety of inherited liver diseases and three healthy individuals (the controls). They then reprogrammed cells from the skin samples back into stem cells. These stem cells were then used to generate liver cells which mimicked a broad range of liver diseases – and to create ‘healthy’ liver cells from the control group.

These hIPSC-generated liver cells can provide in vitro models for basic research and drug discovery. Their use has already reduced the use of animals needed for the production of liver cells in the laboratories that have adopted this technology. The cells could also transform the investigation of chemical/drug-induced liver injury, a major concern for the chemical and pharmaceutical industries, by reducing dependence on animal testing.

Sharmila Nebhrajani, chief executive of the Association of Medical Research Charities (AMRC) said: “Charities invest over £1bn in health research each year, money raised by patients, their families and carers to understand the causes of disease and search for possible cures. Using 3Rs techniques, these prize winning researchers are bringing real hope to people with liver disease. What’s more – they are developing new methods for medical research which should benefit patients with all kinds of conditions.”

On presenting Dr. Vallier with his prize, Professor Paul Matthews, Vice-President for Imaging at GlaxoSmithKline, commented: “Ludovic Vallier’s innovative study describes the development and validation of a method to produce cells similar to those in a human liver. Such cells could replace animals for some types of early drug testing and could also help us to predict adverse clinical reactions. Using these cells for drug testing could be transformative. Ludovic and his colleagues have well illustrated how addressing the 3Rs converges with improving the quality of science!”

Provided by University of Cambridge (news : web)

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Researchers Use Noxious Gas To Convert Stem Cells To Liver Cells

February 27, 2012

Japanese scientists have recently discovered that hydrogen sulfide (H2S) – the chemical responsible for such malodorous phenomena as human flatulence, bad breath and rotten eggs – can be used to efficiently convert stem cells from human teeth into liver cells.

While the fetid chemical compound is produced in small quantities by the human body for use in a variety of biological signaling mechanisms, at high concentrations it is highly poisonous and extremely flammable.

A team of researchers at the Nippon Dental University in Tokyo collected stem cells from the teeth of patients undergoing extractions. The cells were harvested from the central part of the tooth known as the pulp which is made up predominantly of connective tissue and cells.

Stem cells recovered from the pulp were then divided into two groups and incubated in sealed chambers, one filled with hydrogen sulfide and the other a control group.

The cells from each chamber were then examined at three-day intervals to look for signs of transformation into liver cells. One such indicator is the ability to store glycogen, a compound that can be converted to glucose when the body needs energy.

According to a report of their findings that appeared this week in the Journal of Breath Research, the team was able to convert the stem cells to liver cells in relatively high numbers. And what’s more, said the team, H2S appears to help produce comparatively high quality, functional liver cells.

Lead researcher Ken Yaegaki explained that “[h]igh purity means there are less ‘wrong cells’ that are being differentiated to other tissues, or remaining as stem cells … These facts suggest that patients undergoing transplantation with the hepatic cells may have almost no possibility of developing teratomas (malignant tumors) or cancers.”

For the thousands of people around the world with chronic liver disease, this is a most welcome discovery, one that Yaegaki believes could potentially revolutionize this field of medicine.

“Until now, nobody has produced the protocol to regenerate such a huge number of hepatic cells for human transplantation,” added Yaegaki.

“Compared to the traditional method or suing fetal bovine serum to produce the cells, our method is productive and, most importantly, safe.”

Yaegaki’s hope is that his team’s discovery may eventually be fine-tuned to allow scientists to produce ample liver cells in a lab for use in repairing liver damage in human patients.

Moreover, this and similar studies in recent years have also gotten researchers in other fields questioning the possibilities for using hydrogen sulfide with other types of stem cells.

A team of researchers in China, for instance, recently reported using H2S to increase the survival rate of mesenchymal stem cells extracted from the bone marrow of rats.

—

On the Net:

• Nippon Dental University
• Journal of Breath Research Abstract

Source: RedOrbit Staff & Wire Reports

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Also See: Dental pulp stem cells transformed by 'bad breath' chemical (into hepatic (liver) cells)

Dental pulp stem cells transformed by 'bad breath' chemical (into hepatic (liver) cells)

February 26, 2012 in Medical research

Japanese scientists have found that the odorous compound responsible for halitosis – otherwise known as bad breath – is ideal for harvesting stem cells taken from human dental pulp.

In a study published today, Monday 27 February, in IOP Publishing's Journal of Breath Research, researchers showed that hydrogen sulphide (H₂S) increased the ability of adult stem cells to differentiate into hepatic (liver) cells, furthering their reputation as a reliable source for future liver-cell therapy.

This is the first time that liver cells have been produced from human dental pulp and, even more impressively, have been produced in high numbers of high purity.

"High purity means there are less 'wrong cells' that are being differentiated to other tissues, or remaining as stem cells. Moreover, these facts suggest that patients undergoing transplantation with the hepatic cells may have almost no possibility of developing teratomas or cancers, as can be the case when using bone marrow stem cells," said lead author of the study Dr. Ken Yaegaki.

The remarkable transforming ability of stem cells has led to significant focus from research groups around the world and given rise to expectations of cures for numerable diseases, including Parkinson's and Alzheimer's.

In this study, Dr. Ken Yaegaki and his group, from Nippon Dental University, Japan, used stem cells from dental pulp – the central part of the tooth made up of connective tissue and cells – which were obtained from the teeth of dental patients who were undergoing routine tooth extractions.

Once the cells were sufficiently prepared, they were separated into two batches (a test and a control) and the test cells incubated in a H2S chamber. They were harvested and analysed after 3, 6 and 9 days to see if the cells had successfully transformed into liver cells.

To test if the cells successfully differentiated under the influence of H₂S, the researchers carried out a series of tests looking at features that were characteristic of liver cells. In addition to physical observations under the microscope, the researchers investigated the cell's ability to store glycogen and then recorded the amount of urea contained in the cell.

"Until now, nobody has produced the protocol to regenerate such a huge number of hepatic cells for human transplantation. Compared to the traditional method of using fetal bovine serum to produce the cells, our method is productive and, most importantly, safe" continued Dr. Yaegaki.

Hydrogen sulphide (H₂S) has the characteristic smell of rotten eggs and is produced throughout the body in the tissues. Although its exact function is unknown, researchers have been led to believe that it plays a key role in many physiological processes and disease states.

More information: "Hydrogen sulphide increases hepatic differentiation in tooth-pulp stem cells” Ishkitiev et al. 2012 J. Breath Res. 5 017103. http://iopscience. … 3/6/1/017103

Provided by Institute of Physics (news : web)

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Stem Cells Could Advance Hepatitis Research

An image of hepatitis C Image Source: MIT

Drug Discovery & Development - February 02, 2012

Researchers from Massachusetts Institute of Technology (MIT), Rockefeller University, and the Medical College of Wisconsin have developed a way to establish a hepatitis infection in liver-like cells from induced pluripotent stem cells (iPSCs), enabling scientists to study how genetic differences produce varying responses in patients infected with hepatitis C.

Sangeeta Bhatia, a professor of health sciences, technology and electrical engineering, and computer science at MIT and Charles Rice, a professor of virology at Rockefeller University, reported that they could induce liver cells to grow outside the body by growing them on micropatterned plates that direct their organization. The liver cells can be infected with hepatitis C, but they cannot be used to proactively study the role of genetic variation in viral responses because they come from organs that have been donated for transplantation and represent only a small population.

To make cells with more genetic variation, Bhatia and Rice teamed up with Stephen Duncan, a professor of human and molecular genetics at the Medical College of Wisconsin who showed he could transform iPSCs into liver-like cells.

MIT postdoc Robert Schwartz and graduate student Kartik Trehan took the liver-like cells and infected them with hepatitis C. To confirm that infection had occurred, the researchers engineered the viruses to secrete a light-producing protein every time they went through their life cycle.

The researchers’ goal is to take cells from patients who had unusual reactions to hepatitis C infections, transform those cells into liver cells, and study their genetics to see why they responded the way they did. “Hepatitis C virus causes an unusually robust infection in some people, while others are very good at clearing it. It’s not yet known why those differences exist,” Bhatia says.

One potential explanation is genetic differences in the expression of immune molecules such as interleukin-28, a protein that has been shown to play a role in the response to the hepatitis infection. Other possible factors include cells’ expression of surface proteins that enable the virus to enter the cells, and cells’ susceptibility to having viruses take over their replication machinery, and other cellular structures.

The research was published in the Proceedings of the National Academy of Sciences.

Release Date: Feb. 1, 2012
Source: Massachusetts Institute of Technology

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