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#Diabetes may raise risk for heart valve disease Rice university right Original Studyposted by Mike Williams-Rice on October 21 2014 There appears to be a link between high blood sugar and heart valve hardening. Scientists discovered that feeding cells that support heart valves too much glucose slows the cells down. The cells need just the right amount of nutrients to do their job: turning raw materials into heart valves. We ve seen in a variety of other cell types like cells in the kidney the retina and nerves that high glucose concentrations can directly damage those cells and their activities says Peter Kamel a medical student at Baylor College of Medicine who completed the research as an undergraduate at Rice university. That results in patients with diabetes having problems with vision and with their nerves and kidneys as well. The results that high glucose concentration can also cause pathologic remodeling by the aortic-valve cells could suggest that diabetes is also directly a cause of aortic-valve disease he adds. The work was based in the lab of Jane Grande-Allen of Rice s bioengineering department. Her group studies the biomechanics of heart valves particularly their calcification or hardening a condition that lessens blood flow to the heart. In the new study which appears in the Journal of the Royal Society Interface the researchers took on the little-understood process of interstitial valve-cell metabolism. Hardly anything was known about the metabolism of heart valves but metabolism underlies everything Grande-Allen says. It s one of the cell s main orders of business. Kamel started with solutions of collagen the most abundant protein in the body and cells drawn from the aortic heart valves of pigs. Most solutions also included a nutrientâ glucose pyruvate glutamine or a supplement mixture called F-12â to stimulate the cells metabolism. When the cells worked at peak Grande-Allen says they would contract the liquid into a gel as they absorbed and metabolized nutrients and then turned raw collagen into connective tissue. The cells pulled the collagen together and tightened it into packed structures she says. This test is extremely sensitive to how much glucose you give the cells she adds. When we didn t give them any glucose nothing happened. If we gave them just a little we would wait and wait. Sometimes after about two weeks the cells would start contracting. Glucose helps cells do many things. It provides essential fuel for their function and it helps them make carbohydrates that are part of glycoproteins and proteoglycans and glycolipids but the cells have to work really hard to process all that Grande-Allen explains. Maybe that s what s happening to the collagen gel contraction when we give them more glucose. The researchers found solutions with 2 grams of glucose per liter were optimal for contraction. Because off-the-shelf solutions come in standard concentrations of 1 and 4. 5 grams per liter researchers who don t mix their own solutions could easily miss the connection between glucose level and metabolism Kamel notes. It s interesting that the standard concentrations weren t the best Grande-Allen says. I also want to follow up on the effects of higher glucose concentrations she adds. We know that calcific aortic-valve disease is associated heavily with metabolic syndrome which can lead to type 2 diabetes. It s not as common as the link between atherosclerosis and diabetes but it s definitely an appreciable strong subset. To understand any heart valve-related disease we need to understand the mechanism of how the cells interact with excess lipids and sugars and we re just starting to scratch the surface she says. So work like this is pretty fundamental. Researchers from the University of California San diego and the University of Texas Medical school at Houston collaborated on the project. The National institutes of health the Rice Century Scholars Program and a Hamill Innovation Award by the Rice university Institute of Biosciences and Bioengineering supported the research. Source: Rice Universityyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license n

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