A New Source of Stem Cells to Make Pancreatic Beta-Cells
Dr. Fred Levine has developed a new model to study the process by which insulin-producing cells in the pancreas, called beta-cells, arise from precursor cells. The prevailing view has been that new beta-cells arise from stem cells in the pancreatic ducts. However, Levine and colleagues found that new beta-cells arose in large numbers from a completely unexpected source—glucagon-producing cells called alpha-cells. Finding a new source of stem cells raises hopes for regenerative therapies for both type I and type II diabetes.
Glp1: More Than Meets The Islet
Dr. Julio Ayala studies how a gut hormone called Glp1 stimulates the pancreas to produce insulin, affects glucose metabolism in the liver and enhances glucose uptake by muscle cells. Understanding how this hormone modulates insulin signaling could lead to new ways to treat type 2 diabetes. In a recent study, Dr. Ayala and other researchers wondered what would happen if mice engineered to lack the Glp-1 receptor were fed a high- fat diet. They found that disrupting the Glp1 receptor was actually beneficial. When compared to normal mice on a high-fat diet, mice missing the hormone receptor were better at taking up glucose in muscle cells and insulin resistance in the liver was reduced. This was accompanied by a decrease in fat accumulation in the muscle and liver. Further research is needed, but these initial studies indicate Glp1 may be a promising target to treat type 2 diabetes.
Does Obesity Change Fat?
How is fat tissue from an obese person different from a thin person’s fat tissue? Dr. Sheila Collins and her colleagues at Sanford-Burnham’s Diabetes and Obesity Research Center recently discovered one major distinguishing feature – fat tissue from obese people doesn’t oxidize fatty acids as well as that from thinner people. Fat cells use fatty acids for energy. But in response to adrenaline, fat tissue can also release fatty acids into the bloodstream for use by other tissues, such as heart and muscle. This latest study revealed that obese fat tissue was not as good as non-obese fat tissue at consuming fatty acids for energy. This might be one of the reasons why obese fat tissue releases more fatty acids into the bloodstream. And although fatty acids are an important source of energy for other tissues, too much of it in the blood – a condition frequently seen in obesity – is believed to lead to type 2 diabetes and cause detrimental heart problems.
Beta-Cells in a Protective Suit
Dr. Pamela Itkin-Ansari has been developing a novel way to grow pancreatic cells to replace those lost in type 1 diabetes and protect them from the autoimmune response that caused the disease to begin with. Working with San Diego biotech ViaCyte, Dr. Itkin-Ansari and colleagues have demonstrated in mice that transplanted pancreatic precursor cells are protected from the immune system when encapsulated in polytetrafluorethylene, a substance akin to Gore-Tex. The device allows the precursor cells to grow into insulin-producing beta cells, while protecting them from the immune system.
About Sanford-Burnham Medical Research Institute
Sanford-Burnham Medical Research Institute is dedicated to discovering the fundamental molecular causes of disease and devising the innovative therapies of tomorrow. Sanford-Burnham, with operations in California and Florida, is one of the fastest-growing research institutes in the country. The Institute ranks among the top independent research institutions nationally for NIH grant funding and among the top organizations worldwide for its research impact. From 1999 – 2009, Sanford-Burnham ranked #1 worldwide among all types of organizations in the fields of biology and biochemistry for the impact of its research publications, defined by citations per publication, according to the Institute for Scientific Information. According to government statistics, Sanford-Burnham ranks #2 nationally among all organizations in capital efficiency of generating patents, defined by the number of patents issued per grant dollars awarded.
Sanford-Burnham utilizes a unique, collaborative approach to medical research and has established major research programs in cancer, neurodegeneration, diabetes, and infectious, inflammatory, and childhood diseases. The Institute is especially known for its world-class capabilities in stem cell research and drug discovery technologies. Sanford-Burnham is a nonprofit public benefit corporation. For more information, please visit www.sanfordburnham.org.
Sanford-Burnham Researchers Make Gains Against Diabetes
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