Diabetes

Coding Dimension ID: 
289
Coding Dimension path name: 
Diabetes
Funding Type: 
Early Translational I
Grant Number: 
TR1-01215
Investigator: 
Institution: 
Type: 
PI
Institution: 
Type: 
Partner-PI
ICOC Funds Committed: 
$5 405 397
Disease Focus: 
Diabetes
Collaborative Funder: 
Victoria, Australia
Stem Cell Use: 
Embryonic Stem Cell
oldStatus: 
Active
Public Abstract: 

Human embryonic stem cells (hESC), and other related pluripotent stem cells, have great potential as starting material for the manufacture of curative cell therapies. This is primarily for two reasons. First, by manipulating cues in their cell culture conditions, these cells can be directed to become essentially any desired human cell type (a property known as pluripotency). Second, hESC have the remarkable capacity to expand rapidly with essentially no change in their identity. At a practical level, this means enough cells to manufacture thousands, and even millions, of therapeutic cell doses can be generated in a matter of weeks. Thus, the biomedical potential is tremendous, but several practical matters remain to be resolved. One of the biggest concerns is that manufacturing processes, i.e., methods to direct “undifferentiated” hESC to become “differentiated” target cell types, have not shown 100% efficiency. That is, some portion of the starting hESC might not differentiate in accordance with the cues given, resulting in a cell therapy product with some contaminating undifferentiated hESC. When undifferentiated hESC are transplanted into animals, they proliferate and differentiate in an uncontrolled, semi-random manner, becoming non-target cell types collectively called a teratoma. Teratomas also occur spontaneously in humans, and consist of a variety of cell types in a disorganized tissue amalgam. Both experimental and spontaneous teratomas are generally benign tumors, and typically can be surgically removed when they become physically problematic due to size or location. While hESC-derived cell therapies have been shown to be effective in animal models of disease, in some instances teratomas have been observed. Thus, the full promise of hESC as source material for novel cell therapies cannot be fully realized until the “teratoma problem” is solved. To date there is no standard method in the field for testing the teratoma potential of a given cell population, nor is there a method for eliminating the potential for teratoma. The proposed project will investigate and establish standardized tests to measure teratoma potential. The tests will be highly sensitive, allowing assurance that large human doses are produced with no risk of teratoma. The project will also investigate a relatively simple method to eliminate undifferentiated hESC in the course of manufacturing. As the last step, the new method will be incorporated into the manufacturing process, the sensitive teratoma tests will be used, and safety data required by the FDA will be collected for a promising new hESC-derived cell therapy for insulin-dependent diabetes. Successful completion of this project will represent a major advance in development of stem cell-derived therapies broadly, and will specifically contribute to the development of a cell therapy for diabetes.

Statement of Benefit to California: 

In large part through CIRM initiatives, California hopes to further establish itself as the world center for stem cell research and stem cell-derived therapies. One major issue standing in the way of stem cell-derived therapy development is the possibility of a teratoma forming after transplant with a stem cell-derived cell therapy. A teratoma is a disorganized tissue amalgam containing various different cell types, and is generally a benign tumor. Teratomas can form in animals transplanted with stem cells, and therefore if some stem cells persist in the stem-cell derived therapy, there exists a possibility that teratomas will form in a patient’s graft. Indeed, putative stem cells have been found in pre-clinical research-grade stem cell-derived cell therapy preparations, and teratomas have been observed in animals treated with those cells. Currently the conditions favorable to teratoma formation are poorly characterized, and methods to reduce the likelihood of teratoma formation have not been developed. The proposed project will establish standardized sensitive methods to measure the teratoma potential of a cell population, will develop a method to reduce or eliminate teratoma potential, and will include both the method to reduce teratoma and the standard measurement of teratoma potential in the development of an actual prospective cell therapy product for the treatment of insulin-dependent diabetes. If successful, this project will remove a significant bottleneck currently holding the development of stem cell-derived cell therapies back, as well as provide essential pre-clinical data for an important stem cell-derived therapy for diabetes, facilitating its clinical testing in diabetics. The State of California will benefit by playing a key role in removing the teratoma bottleneck from the field, as well as in advancing a promising new cell therapy for diabetes, a disease which directly or indirectly affects millions of Californians. Such a therapy could reduce the state's health care costs tremendously.

Progress Report: 
  • ViaCyte is developing a cell therapy for diabetes, which will have a tremendous clinical and societal impact as such a large number of people are afflicted with this disease. The therapy is a combination product comprised of pancreatic progenitor cells transplanted within a device, Encaptra™. A large supply of pancreatic progenitors can be produced with a cell manufacturing process that involves the directed differentiation of human embryonic stem cells (hESC). After transplantation the pancreatic progenitor cells differentiate into functional islets that contain insulin-producing beta cells. Encaptra™ is designed to allow the release of insulin to regulate blood glucose levels while simultaneously protecting the transplanted cells from destruction by the patients’ immune system. The combined product provides a large assurance of safety since cells will be contained and the device is retrievable.
  • This award is focused on product safety, principally the issue of tumorigenicity. Tumor formation is a particular consideration when using hESCs as cell manufacturing starting material since undifferentiated hESCs form a particular type of tumor, called a teratoma, when transplanted into animal models. Therefore, it is important to demonstrate that at the end of the manufacturing process the cell product is largely devoid of undifferentiated hESC and lacks teratoma potential. ViaCyte has been investigating and establishing standardized assays to measure the presence of hESCs and the potential for teratoma formation. In addition, ViaCyte has previously identified several compounds that appear to preferentially kill undifferentiated hESCs while not affecting the viability of pancreatic progenitors. To ensure that Encaptra™ will be fully effective in containing implanted cells in a patient, ViaCyte is developing various assays to ensure the quality of manufactured devices. These newly developed assays will be incorporated into the manufacturing process and data required by the FDA for product safety will be collected. Successful completion of this project will represent a major advance for stem cell-derived therapies and will specifically contribute to establishing a cell therapy for diabetes.
  • ViaCyte is a preclinical company developing a stem cell-based therapy for insulin-dependent diabetes. The therapy is a combination product comprised of pancreatic progenitor cells, pro-islet, encapsulated within a retrievable delivery ENCAPTRA device. After implantation, encapsulated pro-islet differentiates into glucose-responsive, insulin-secreting cells that can regulate normal blood sugar levels in animal models of diabetes. The renewable starting material for pro-islet manufacturing is human embryonic stem cells (hESC) that are directed to differentiate to pancreatic cell product using scalable processes. The bio-stable ENCAPTRA device is designed to fully contain cells and to protect cells from immune attack. The goal is to develop a product that will achieve insulin independence, reduce diabetes-related complications, and eliminate the need for continuous immunosuppressant drugs.
  • This CIRM award is focused on product safety. A large assurance of safety is provided by confining the transplanted cells within the device and by the ability to retrieve the product. Nonetheless, an important preclinical safety assessment of this combination product therapy is the evaluation of its tumorigenicity, i.e. its capacity to form tumors. Upon transplantation into animal models, undifferentiated hESC can generate a teratoma, a tumor that is akin to a particular type of germ cell tumor that can form in humans. There is a possibility that residual, undifferentiated hESC could remain in pro-islet, potentially giving rise to a teratoma. It is unclear whether teratomas can form when undifferentiated hESC are transplanted within ENCAPTRA and if so, what threshold dose of hESC in pro-islet could generate a teratoma.
  • ViaCyte has been investigating and establishing standardized assays to measure the presence of hESC in pro-islet and the potential for teratoma formation. Preliminary tumorigenicity studies of pro-islet were completed with safe outcomes. With these data in hand, formal definitive tumorigenicity studies can be designed and initiated to include in a package to submit to the FDA as ViaCyte seeks approval to test the product in humans. To demonstrate that ENCAPTRA will be effective in containing implanted cells in a patient, ViaCyte is also developing assays to ensure the quality of manufactured devices. These newly developed assays are being incorporated into the cell manufacturing and device manufacturing processes, and data will be collected to show that the product is safe. Successful completion of the objectives of this award will help establish the safety of the product so that clinical trials can be initiated with the goal of developing a game-changing cell therapy for diabetes.
  • ViaCyte is a company developing a stem cell-based therapy for diabetes. The therapy is a combination product, called VC-01™, comprised of human embryonic stem cell (hESC)-derived pancreatic beta cell precursors (PEC-01™ cell product), encapsulated within the Encaptra® drug delivery system (ENCAPTRA device). After implantation, the precursor cells mature into endocrine cells that secrete insulin and other hormones in a regulated manner to control blood sugar levels in animal models of diabetes. hESC are the renewable starting material for cell manufacturing; they are directed to differentiate to PEC-01 cell product using scalable processes. The retrievable ENCAPTRA device is designed to contain cells and to protect cells from immune attack. The goal is to develop a product that will provide insulin independence, reduce diabetes-related complications, and eliminate the need for chronic immunosuppressant drugs.
  • This CIRM award is focused on product safety. An important nonclinical safety assessment of this combination product therapy is the evaluation of its tumorigenicity, i.e., its capacity to form tumors. Upon transplantation into animal models, undifferentiated hESC can generate a teratoma, a tumor that is akin to a particular type of germ cell tumor that can form in humans. Accordingly, to the extent that undifferentiated hESC could potentially remain in the differentiated PEC-01 cell product, these could potentially give rise to a teratoma. Prior to this award, it was unclear whether teratomas will form when undifferentiated hESC are implanted within the ENCAPTRA device and if so, what threshold dose of hESC in PEC-01 would be required to produce a teratoma.
  • ViaCyte received this award to develop methods to assess teratoma potential with in vivo and in vitro assays, and to mitigate potential tumorigenicity risk by ensuring integrity of the encapsulation delivery device. ViaCyte has investigated a standardized assay to measure the presence of hESC in PEC-01 cell product, and preliminary tumorigenicity studies of VC-01 were completed with safe outcomes. With these data in hand, definitive IND-enabling tumorigenicity studies were designed and initiated to include in a package that will be submitted to the FDA as ViaCyte seeks approval to test the product in human clinical trials. A large assurance of safety is provided by confining the transplanted cells within the device and by the ability to retrieve the product. To demonstrate that the ENCAPTRA device will be effective in containing implanted cells in a patient, ViaCyte has also developed assays and performed studies to ensure the integrity of the ENCAPTRA device. Collectively, the data from these studies will form a compelling package to demonstrate the safety of the VC-01 product so that clinical trials can be initiated with the goal of developing a game-changing cell therapy for diabetes.
  • ViaCyte is a company developing a stem cell-based therapy for diabetes. The therapy is a combination product, called VC-01™, comprised of human embryonic stem cell (hESC)-derived pancreatic beta cell precursors (PEC-01™ cell product), encapsulated within the Encaptra® drug delivery system (ENCAPTRA device). After implantation, the precursor cells mature into endocrine cells that secrete insulin and other hormones in a regulated manner to control blood sugar levels in animal models of diabetes. hESC are the renewable starting material for cell manufacturing; they are directed to differentiate to PEC-01 cell product using scalable processes. The retrievable ENCAPTRA device is designed to contain cells and to protect cells from immune attack. The goal is to develop a product that will provide insulin independence, reduce diabetes-related complications, and eliminate the need for chronic immunosuppressant drugs.
  • This CIRM award is focused on product safety. An important nonclinical safety assessment of this combination product therapy is the evaluation of its tumorigenicity, i.e., its capacity to form tumors. Upon transplantation into animal models, undifferentiated hESC can generate a teratoma, a tumor that is akin to a particular type of germ cell tumor that can form in humans. Accordingly, to the extent that undifferentiated hESC could potentially remain in the differentiated PEC-01 cell product, these could potentially give rise to a teratoma. Prior to this award, it was unclear whether teratomas will form when undifferentiated hESC are implanted within the ENCAPTRA device and if so, what threshold dose of hESC in PEC-01 would be required to produce a teratoma.
  • ViaCyte received this award to develop methods to assess teratoma potential with in vivo and in vitro assays, and to mitigate potential tumorigenicity risk by ensuring integrity of the encapsulation delivery device. ViaCyte has investigated a standardized assay to measure the presence of hESC in PEC-01 cell product, and preliminary tumorigenicity studies of VC-01 were completed with safe outcomes. With these data in hand, definitive IND-enabling tumorigenicity studies were designed and initiated to include in a package that will be submitted to the FDA as ViaCyte seeks approval to test the product in human clinical trials. A large assurance of safety is provided by confining the transplanted cells within the device and by the ability to retrieve the product. To demonstrate that the ENCAPTRA device will be effective in containing implanted cells in a patient, ViaCyte has also developed assays and performed studies to ensure the integrity of the ENCAPTRA device. Collectively, the data from these studies will form a compelling package to demonstrate the safety of the VC-01 product so that clinical trials can be initiated with the goal of developing a game-changing cell therapy for diabetes.
Funding Type: 
Transplantation Immunology
Grant Number: 
RM1-01703
Investigator: 
ICOC Funds Committed: 
$1 152 768
Disease Focus: 
Diabetes
Immune Disease
Stem Cell Use: 
Embryonic Stem Cell
Cell Line Generation: 
Embryonic Stem Cell
oldStatus: 
Active
Public Abstract: 

Type 1 Diabetes (T1D) occurs as a consequence of uncontrolled immune activation, culminating in the destruction of insulin-producing beta-cells. Efforts to prevent or reverse diabetes have been limited by the lack of safe and effective immunotherapies coupled with the inability to restore insulin producing beta-cells. We believe proper immune control to self-tissues to be a fundamental requirement for any effective therapy, whether the goal is prevention of early beta-cell loss, beta-cell regeneration at disease onset, or ultimately beta-cell replacement in cases of established T1D. To impact disease, any effective therapy must first restore a glucose-responsive insulin-producing beta-cell population. Stem cells represent one of the most promising alternative sources of insulin-producing cells. Second, a therapy must combat the persistent autoimmune attack, as well as any attack directed at foreign tissues following transplantation. The goal of this project is to bring together research efforts in these two complementary areas to fill these critical gaps. Previous studies have focused on the use of regulatory T cells (Tregs) as one key means of restoring immune tolerance in T1D. A key parameter has been the importance of antigen specificity in directing the tissue-protective functions of Tregs. In the prevention setting, antigen-specific Tregs were at least 100-fold more effective in controlling diabetes when compared to Tregs with diverse receptors. Importantly, treatment with antigen-specific Tregs is capable of reversing diabetes in the non-obese diabetic (NOD) mouse model of T1D. Likewise, these Tregs have also been shown to be important in preventing tissue rejection in the transplantation setting. Thus, Treg specificity determined by the T cell receptor can be exploited to selectively suppress a particular component of an ongoing immune response. The translation of this knowledge requires a robust means to generate a large number of patient-derived antigen-specific Tregs. The goal of this proposal is to test the hypothesis that the introduction of antigen-specific Tregs will be able to correct the initiating and persistent autoimmunity in T1D, as well as prevent the transplant-mediated destruction of beta-cells following stem cell transplantation. Thus, we propose to develop engineered tissue-directed human regulatory T cells capable of suppressing autoimmune and transplant-related destruction of beta-cells. To generate these cells we will deliver the specific T cell receptors (TCRs) by gene therapy delivery mechanisms to a patient’s own Treg population and test their ability to suppress specific immune responses in immunodeficient mice following beta-cell replacement therapies.

Statement of Benefit to California: 

Type 1 diabetes (T1D), previously referred to as Juvenile Diabetes, is a chronic condition that leads to devastating consequences for patients and places a huge financial burden on the California health care system. T1D occurs as a consequence of the systematic immune destruction of the insulin-producing beta cells in the pancreas. Once those cells are destroyed, the production of insulin is dramatically compromised and patients lose the ability to control blood sugar levels. Chronic periods of elevated blood sugar result in numerous secondary complications including heart disease, blindness, kidney failure, and abnormal nervous system function, among others. There is currently no known way to prevent T1D. According to the California Department of Public Health, there were 2.7 million Californians with diabetes in 2007, meaning that 1 out 10 adult Californians has diabetes. Of these, approximately 5-10% of patients have T1D, with the remainder consisting of patients with insulin-resistant type 2 diabetes. Of particular concern, the incidence rate of T1D has been increasing, particularly in children 5 years old and under. T1D is the second most common chronic disease in children, second only to asthma. Consequently T1D, and improved therapeutic approaches for this disease, are issues of great importance to the people of California.
Intensive insulin therapy is the only current treatment for T1D. While effective at reducing blood sugar levels in the short term, insulin therapy does not address the underlying autoimmune attack which leads to T1D. Our studies will explore the potential use of human embryonic stem cells to restore insulin-producing cells. In addition, we are exploring ways to genetically modify (through the use of gene therapy) a population of regulatory cells (Tregs) within the immune system to stop the autoimmune attack that initiates T1D. We expect that these modified Tregs will not only stop the autoimmune process, but will also protect against the immune attack which normally arises against the transplanted tissues and any stem cell-derived tissues. We hope to eventually use these procedures to treat patients with T1D. If successful, our results may allow patients with T1D to discontinue, or greatly reduce the amount of insulin they must currently take to maintain normal blood sugar levels. This approach will directly benefit those with T1D, as well as the general population by reducing the health care burden associated with the care of this chronic disease.

Progress Report: 
  • Type 1 diabetes (T1D) is caused by the destruction of insulin producing b-cells in the pancreatic islets by an overactive self immune system. Due to lack of ways of preventing T1D, insulin administration is currently most common method of treatment, but susceptible to developing serious, long-term complications. Islet transplantation provides an excellent alternative and can improve glycemic control and reduce the risk of further complications associated with diabetes. Transplantation of pancreas or isolated islets across immune barriers has been conducted with some efficacy but is limited by inadequate organ availability and the need for long-term non-specific immunosuppression. The ability to transplant a renewable supply of islets or β-cells would have a dramatic impact on the disease. Human embryonic stem cells (hESC) represent one of the most promising alternative sources of β-cells, given their pluripotent and self-renewing properties. However, we hypothesized that the immunocompetent recipients will recognize the product as foreign (and autoimmune-self) due to MHC-mismatch (allogeneic) between donor and recipient, leading to transplant rejection. Thus, in order to make stem cell-derived islet cell therapy both commercially and clinically viable, β-cell protective therapies need to be developed to combat the strong allogeneic immune response, as well as the recurrent autoimmune attack which caused the disease in the first place.
  • In previous studies, we have shown that a small population of CD4+ regulatory T cells (Tregs) plays a critical role in controlling self-reactivity thus maintaining immune tolerance. Adoptive immunotherapy with Tregs into diabetes prone non-obese diabetic (NOD) mice can restore immune tolerance leading to a long-term cure of T1D and have shown a lot of promise for the treatment of autoimmune diseases in the preclinical studies. A key parameter has been the enhanced activity of antigen specificity in directing the tissue-protective functions of Tregs. Thus, in this proposal, we proposed to exploit antigen-specific Treg to selectively regulate ongoing immune responses while avoiding the need for pan-immunosuppression. In the past year, we have made significant, albeit slow progress in this effort. We have taken significant steps to develop an approach to expand alloantigen-specific Tregs (those that recognize and suppress immune responses against foreign tissues) from patients with T1D. We have cloned and expressed self-antigen-specific T cell receptor genes in expanded Tregs to determine their ability to suppress stem cell-derived islet transplants. We have established a humanized mouse model to test the hypothesis that engineered antigen-specific Tregs will potently suppress rejection of stem cells. We set up a mouse model of islet transplantation by implanting human islets (from cadavers) in mice lacking a functional immune system. These islets were functional and produced insulin to control normal glucose levels in mice. However, when these mice were complemented with human immune system, the islet grafts were rejected by the allogeneic immune response. This provides an excellent mimic to the human islet transplant where a similar allogeneic immune response leads to the graft rejection. This will provide a setting for testing the engineered Tregs. More over, we have shown that self-antigen and alloreactive Tregs can be generated and transferred in to this humanized mouse setting. Unfortunately, we were unable to test the stem cell-derived islets in this setting as yet due to unexpected challenges in our efforts to produce these cells due to technical problems. However, significant progress has been made to rectify these problems and we are confident that we will succeed in using stem cell-derived islets in the coming year.
  • Type 1 diabetes (T1D) is caused by the destruction of insulin producing b-cells in the pancreatic islets by an overactive self immune system. Due to lack of ways of preventing T1D, insulin administration is currently most common method of treatment, but susceptible to developing serious, long-term complications. Islet transplantation provides an excellent alternative and can improve glycemic control and reduce the risk of further complications associated with diabetes. Transplantation of pancreas or isolated islets across immune barriers has been conducted with some efficacy but is limited by inadequate organ availability and the need for long-term non-specific immunosuppression. The ability to transplant a renewable supply of islets or β-cells would have a dramatic impact on the disease. Human embryonic stem cells (hESC) represent one of the most promising alternative sources of β-cells, given their pluripotent and self-renewing properties. However, we hypothesized that the immunocompetent recipients will recognize the product as foreign (and autoimmune-self) due to MHC-mismatch (allogeneic) between donor and recipient, leading to transplant rejection. Thus, in order to make stem cell-derived islet cell therapy both commercially and clinically viable, β-cell protective therapies need to be developed to combat the strong allogeneic immune response, as well as the recurrent autoimmune attack which caused the disease in the first place.
  • In previous studies, we have shown that a small population of CD4+ regulatory T cells (Tregs) plays a critical role in controlling self-reactivity thus maintaining immune tolerance. Adoptive immunotherapy with Tregs into diabetes prone non-obese diabetic (NOD) mice can restore immune tolerance leading to a long-term cure of T1D and have shown a lot of promise for the treatment of autoimmune diseases in the preclinical studies. A key parameter has been the enhanced activity of antigen specificity in directing the tissue-protective functions of Tregs. Thus, in this proposal, we proposed to exploit antigen-specific Treg to selectively regulate ongoing immune responses while avoiding the need for pan-immunosuppression. In the past year, we have made significant, albeit slow progress in this effort. We have taken significant steps to develop an approach to expand alloantigen-specific Tregs (those that recognize and suppress immune responses against foreign tissues). We have developed a process for isolating and expanding alloantigen-specific Tregs to determine their ability to suppress stem cell-derived islet transplants. We have established a humanized mouse model to test the hypothesis that alloantigen-specific Tregs will potently suppress rejection of stem cells. We set up a mouse model of islet transplantation by implanting human islets (from cadavers) in mice lacking a functional immune system. These islets were functional and produced insulin to control normal glucose levels in mice. However, when these mice were complemented with human immune system, the islet grafts were rejected by the allogeneic immune response. This provides an excellent mimic to the human islet transplant where a similar allogeneic immune response leads to the graft rejection. This will provide a setting for testing the allospecific Tregs.
  • This year we have begun to test the stem cell-derived islets in this setting. First, we have developed a more efficient and effective protocol for developing pancreatic endoderm from human embryonic stem cells. These cells have been transferred into immunodeficient mice and shown to produce human insulin after some period of time (3 months). In addition, we have developed in vitro modifications of the differentiation process that has enabled the formation of cells that express markers of fully matured insulin producing cells without extensive in vivo maturation whose functionality is currently assessed. Finally, we have been able to mimic this process using a genetically marked ES population (luciferase transduced). This allows for rapid and ongoing analysis of cell survival in transplanted animals to enable rapid and extensive therapeutic interventions.
  • Finally, we have validated a humanized mouse model that allows an analysis of alloreactive Tregs in this setting. Thus, in the coming year, we fully expect to be able to test the hypotheses posed in the original application, as all the tools are now available. In addition, we will work towards adapting the process to the analysis of iPS cells.
  • The goal of this project was to using novel immune techniques to block rejection of human ES cell derived islet precursors in mouse models of diabetes. during the past three years, we identified and developed islet specific regulatory T cells that could be used to suppress immune responses to the stem cell-derived islets. we also established, with some difficulty, a more robust methodology to direct the differentiation of human ES cells into islet precursors for transplantation. the studies were not complete but demonstrated in proof of principle studies that the tools can be generated to address the primary questions posed in this project.
Funding Type: 
Tools and Technologies I
Grant Number: 
RT1-01093
Investigator: 
Institution: 
Type: 
PI
ICOC Funds Committed: 
$827 072
Disease Focus: 
Diabetes
Stem Cell Use: 
Adult Stem Cell
Embryonic Stem Cell
oldStatus: 
Closed
Public Abstract: 

There are several challenges to the successful implementation of a cellular therapy for insulin dependent diabetes derived from Human Embryonic Stem Cells (hESCs). Among these are the development of functional insulin-producing cells, a clinical delivery method that eliminates the need for chronic immunosuppression, and assurance that hESC-derived tumors do not develop in the patient.

We have recently developed methods to efficiently generate such insulin-producing cells from Human Embryonic Stem Cells that can prevent diabetes in mouse models of the disease. The results demonstrated for the first time that Human Embryonic Stem Cells could indeed serve as a source of cellular therapy for diabetes. However, the clinical use of Human Embryonic Stem Cell-derived cell products is hampered by safety concerns over the potential growth of unwanted cell types and the formation of tumors.

Encapsulation of cellular transplants has the potential to reduce or eliminate the need for immunosuppression. Moreover, a durable immunoprotective device which prevented cell escape could serve as a platform for safely administering Human Embryonic Stem Cell-derived therapies. The [REDACTED] device, a planar polytetrafluorethylene (PTFE) pouch-like encapsulation device, features 100% encapsulation and is fully retrievable. We and others have demonstrated in various animal models that the device provides obust protection of transplanted cells against immune attack from the host, [REDACTED] -encapsulated insulin-producing cells can correct diabetes in animals, and the device can prevent the escape and spread of cancer cells.

Therefore, the goal of the proposed studies is to evaluate the retrievable [REDACTED] cell encapsulation device in combination with Human Embryonic Stem Cell-derived pancreatic progenitor cells for the treatment of diabetes in mice.

Statement of Benefit to California: 

With a current prevalence of greater than 170 million individuals world-wide, diabetes has attained epidemic proportions. The widespread secondary complications of kidney failure, cardiovascular disease, peripheral nerve disease, and severe retinopathies, this disease extracts a relentless and costly toll on the patients and the health care establishments required for their treatment. Current estimates are that California spends minimally $12 billion on diabetes not including lost wages. There are more than 300,000 diabetes related hospitalizations costing $3.4 billion annually. To date, cellular replacement has been performed either by transplantation of whole pancreas organs, or via infusion of isolated primary pancreatic islets into the portal vein . While effective, the availability of such procedures is severely limited for the treatment of the general diabetes population since it relies upon the extremely limited supply of pancreas organs from deceased donors and usually requires life-long administration of immuno-suppressive drugs.

Recent advances in human embryonic stem cell research indicate that the production of a virtually unlimited supply of functional insulin-producing cells is possible. However, much research is required to determine how to safely administer such cells as a therapy because they could give rise to tumors. The animal studies proposed in this application address this with a device that could both protect the therapeutic cells from host immune attack, and protect the host from tumor formation. If successful, our research would provide a possible opportunity for safely administering a diabetes therapy derived from human embryonic stem cells.

Progress Report: 
  • Currently, the shortage of donor organ tissue and risks associated with lifelong immunosuppression limit islet transplantation to only the most severely impacted brittle patients with diabetes. Thus, successful development of a universal cell therapy to treat diabetes requires a renewable safe source of glucose responsive human islet cells and a means for their delivery without the use of chronic immunosuppression. While human embryonic stem cells (hESCs) represent an excellent starting material for the generation of numerous islet cells, the clinical use of hESC-derived cell products is hampered by safety concerns over the potential growth of unwanted cell types and the formation of teratomas. A cell delivery system that allows for both segregation of the hESC-derived graft from host tissues and complete retrieval of the engrafted cells would provide an additional level of safety for hESC-derived cell therapies. The rationale behind this proposal, therefore, is to evaluate an immunoisolation device in combination with hESC-derived pancreatic progenitors as a means for the widespread treatment of diabetes without immunosuppression.
  • Immunoisolation involves the encapsulation of therapeutic graft cells in a membrane (essentially a sealed pouch) thereby protecting the graft from direct contact with the host immune cells and potentially reducing and/or eliminating the need for chronic co-administration of potent anti-rejection drugs for the life of the graft. The encapsulating membrane physically separates the graft cells from host tissues and vasculature. Therefore, to maintain viability and functional metabolism of the graft, the membrane must permit adequate diffusion of oxygen, nutrients, and waste-products, while also preventing exposure to host immune cells. Finally, an encapsulating membrane ideally allows for the timely delivery of insulin at levels that maintain safe and stable blood sugar levels.
  • Our hESC-derived pancreatic progenitor cells are first implanted and the cells complete their maturation to fully functional glucose-responsive islet cells several weeks after engraftment into a host animal. One of the notable achievements over the past year has been the demonstration that the encapsulation device can not only sustain the viability of the pancreatic progenitor cells, but also supports the maturation of those cells to fully functional glucose responsive endocrine tissue. We also have demonstrated that encapsulated grafts prevent the development of diabetes in animals that are treated with a toxin that selectively kills their endogenous pancreatic insulin producing beta cells. The encapsulated grafts maintained normal blood sugar levels in these animals, essentially functioning in place of their beta cells. Finally, all of the encapsulated grafts were fully contained in the interior of the device and there were no breached or ruptured devices observed, even when highly proliferative cells were encapsulated in the device. These results suggest that such an encapsulation device may be a viable system to safely deliver an hESC-derived cell therapy for diabetes.
  • During the second year of our grant we have determined two important features:
  • 1- The encapsulation device we assessed here allows for the efficient development of functional insulin-producing grafts derived from differentiated human embryonic stem cells. We show that in the vast majority of implanted mice (93%) robust insulin-production was detected. Moreover, supporting their potential therapeutic value, in 19 of 19 animals that were challenged with the chemical destruction of their own insulin-producing cells the encapsulated grafts prevented the onset of diabetes.
  • 2- We have used an imaging technology and genetically modified human embryonic stem cells to assess the grafts of differentiated embryonic stem cells in animals as the functional insulin delivery capacity develops over time. These studies showed that the encapsulation device fully contains the grafts: no hESC-derived cells were found outside of the implanted encapsulation device. This supports the premise that the device can be used to safely administer a population of cells derived from hESC.
Funding Type: 
SEED Grant
Grant Number: 
RS1-00308
Investigator: 
ICOC Funds Committed: 
$635 242
Disease Focus: 
Diabetes
Stem Cell Use: 
Embryonic Stem Cell
oldStatus: 
Closed
Public Abstract: 

The goals of this proposal are to investigate endodermal differentiation and proliferation in human ES cell cultures. Endodermal cells give rise to the epithelial lining of the respiratory and digestive tract as well as to the liver and pancreas. The future treatment of diseases such as type I diabetes using stem cell therapy relies on our ability to differentiate stem cells into endoderm, a prerequisite step to forming pancreatic beta cells. In 2005, D’Amour et al. reported the efficient differentiation of human ES cells into endoderm. This report provides a potentially effective protocol that needs to be further evaluated (specific aim 1). In addition, given that the success of stem-cell therapy depends on our ability to generate large numbers of differentiated cells (e.g. 200-700 million beta cells per patient are currently being used in the Edmonton protocol), we will investigate the ability of the endodermal generated in specific aim 1 cells to proliferate in culture (specific aim 2).

Statement of Benefit to California: 

Stem cell therapy relies on the development of efficient and reproducible protocols to differentiate stem cells into various cell types such as pancreatic beta cells. The first step to making pancreatic beta cells is the differentiation of stem cells into so-called endodermal cells, one of the 3 basic cell types of the body. In addition, in order to make stem cell therapy a viable option, one needs to be able to generate large numbers of differentiated cells from stem cells. Our proposal aims to establish such protocols. The health of California and its citizens will ultimately benefit from this research as it will help develop stem cell therapies.

Progress Report: 
  • The goals of this proposal are to investigate endodermal differentiation and proliferation of human ES cells in culture. Endodermal differentiation is a necessary step towards making pancreatic beta cells, as well as other endodermal cells such as liver cells. Pancreatic beta cells generated from human ES cells could be used to treat type I diabetics. In the past two years, we have incorporated human ES cell culture technology into our laboratory and have been able to replicate data obtained by other research groups. While several other research groups and companies around the world are focused on making pancreatic beta cells as quickly as possible, we strongly believe that a more detailed understanding of the biology of human ES cell differentiation into endoderm will help the optimization of this protocol. Therefore, we have focused our efforts on testing a number of variables in the initial step of creating definitive endoderm. We have found that different human ES cell lines have very different capacity to differentiate into endoderm under the same culture conditions. In addition, we have recently focused our research effort on the post-translational modifications of key regulators of endoderm differentiation, and found a critical role for a poorly appreciated modification, namely a sugar modification called GlcNAcylation. In summary, developing a reproducible and efficient way to differentiate human ES cells into endoderm, as well as a thorough understanding of this key step, will allow us and others to elucidate the detailed set of molecular and biochemical events underlying this critical differentiation step, and will improve differentiation protocols.
  • The goals of this proposal are to investigate endodermal differentiation and proliferation of human ES cells in culture. Endodermal differentiation is a necessary step towards making pancreatic beta cells, as well as other endodermal cells, such as liver cells. Pancreatic beta cells generated from human ES cells could be used to treat type I diabetes. In the past two years, we have incorporated human ES cell culture technology into our laboratory and have been able to replicate data obtained by other research groups. While several other research groups and companies around the world are focused on making pancreatic beta cells as quickly as possible, we strongly believe that a more detailed understanding of the biology of human eS cell differentiation into endoderm will help the optimization of this protocol. Therefore, we have focused our efforts on testing a number of variables in the initial step of creating definitive endoderm. We have found that different human ES cell lines have very different capacity to differentiate into endoderm under the same culture conditions. IN addition, we have recently focused our research effort on the post-translational modifications of key regulators of endoderm differentiation, and found a critical role for a poorly appreciated modification—namely a sugar modification called GlcNAcylation. In summary, developing a reproducible and efficient way to differentiate human ES cells into endoderm, as well as thorough understanding of this key step, will allow us and others to elucidate the detailed set of molecular and biochemical events underlying this critical differentiation step, and will improve differentiation protocols.
  • We initiated a project on the role of post-translational modifications during hES cell differentiation into endodermal lineages, specifically on the GlcNAcylation sugar modification. We found that this modification appears to be important for endoderm formation in hES cell cultures. Identification of modified proteins is an important next step in understanding the mechanisms of this phenomenon and may ultimately provide a basis to develop assays for screening drugs that enhance endoderm/beta-cell formation.

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