Tissera Reports Encouraging Preliminary Results of its Large Animal Diabetic Model Experiments of Pancreatic Xenotransplantation
Wednesday, 6 December 2006

Tissera, Inc. (OTCBB: TSSR – News) reports encouraging preliminary results of its large animal diabetic model experiments of pancreatic xenotransplantation, designed for the future treatment of insulin-dependent (type I) diabetes mellitus.

Based on the previously reported  positive results obtained in pancreatic transplantation experiments in normal non human primates, Tissera's sponsored research team at the Weizmann Institute of Science has moved forward to investigate in diabetic non human primates the functional and therapeutic value of the company's approach. In these studies, non human primates are treated by an agent called streptozotocin (STZ) which induces them to become diabetic and consequently dependent upon administration of exogenous insulin for the maintenance of reasonable blood sugar levels. After allowing a few days for stabilization, appropriately timed pig embryonic pancreatic tissue is transplanted into the diabetic primate, which is thereafter intensively and carefully followed.   

As part of the results obtained so far, a progressive post transplantation reduction of the insulin amounts required for maintenance of blood sugar levels has been observed, together with the demonstration of the presence of slight blood insulin levels, suggestive of endogenous insulin production, which might be attributed to the growing pancreatic graft, though the pig origin of this insulin remains to be verified.

Tissue examination showed considerable growth of the engrafted tissue, with persisting significant proliferation of the transplanted cells and a pronounced presence of endocrine elements, notably islet cells, responsible for the production of insulin, the hormone deficient in type I diabetes. No signs of rejection of the pig embryonic pancreatic implants were detected and the tissues were shown to be wholly vascularized by the host primate blood vessels, a fact of great importance for the successful acceptance and thriving of the graft. The ability of the transplanted tissues to produce hormones was demonstrated by specific staining for the presence of intra-cellular insulin and glucagon.

A significant difficulty encountered in those experiments has to do with the dosage of the immune suppression treatment initially given for the prevention of rejection, which was found to be eventually lethal in several cases. This issue is and will be carefully addressed in the company's current and future experiments, by a well-planned and fined tuned progressive reduction of administered immune suppression doses.

Altogether, those are positive and encouraging preliminary data, though it must be emphasized that further work and follow up is needed to clarify whether this tendency of reduction of insulin requirements persists over time and whether complete weaning from exogenous insulin dependence can be achieved, under an appropriate immune suppression treatment.  

Amos Eiran, Tissera's Chairman & CEO further comments: "The diabetic primate model experiments are still ongoing and further time for the current and future additional experiments must be allowed in order to reach conclusive results, which, if in line with the present positive data, shall advance the company towards its next goal of applying for the initiation of human clinical studies on Type I diabetic patients in approximately 18 months".

About Diabetes Mellitus

Diabetes mellitus is a severe and debilitating chronic disease that develops in nearly 5 percent of the world’s population.  People with this disease have a shortage of insulin or a reduced ability to use insulin, the hormone regulating blood glucose levels, which is normally produced by the pancreas. In the United States alone, an estimated 18 million people have diabetes, and each year about 1 million Americans are diagnosed with the disease.  It is the sixth leading cause of death in the US and is responsible for over 200,000 deaths a year. Insulin-dependent (type I) diabetes accounts for around 10% of diabetics. For those patients, suffering from an inability of their pancreas to produce insulin, the only practical treatment possible is regular insulin replacement by multiple daily injections. Transplantation of a pancreas or pancreatic tissue would be beneficial to millions of such patients in that it would restore their normal ability to produce self insulin. Transplantation of human pancreas or pancreatic islets is a practiced and time-honored  such therapeutic approach, but is extremely limited by the severe shortage of human donor organs. Tissera's R&D efforts in this domain are directed towards the development of a universally available and reliable source of animal fetal donor pancreatic precursor tissue, suitable for transplantation and eventual normal structural and functional growth in human diabetics.

About Tissera

Tissera is a biotechnology company dedicated to the development of novel tissue precursor regeneration technologies for treating gene deficiencies and diseases in which organ transplantation is necessary, while minimizing the dosage of immunosuppressive drugs. Tissera obtained the license for the worldwide exclusive rights to the technology developed by Professor Yair Reisner and his team at the Weizmann Institute of Science in Israel. In this research, scientists successfully implanted in mice embryonic human and porcine organ precursor tissues, which grew into functional organs. This research was published in Nature Medicine and attracted worldwide scientific and media attention.

For more information please visit Tissera website: