Abstract 308: Controlling Methylglyoxal To Prevent The Development Of Diabetic Cardiomyopathy
Hyperglycemia caused by diabetes leads to increased glucose oxidation and mitochondrial generation of superoxide. One of the most abundant by-products of glucose oxidation is methylglyoxal (MG). MG has been implicated in the development of diabetic complications. Diabetic cardiomyopathy, characterized by systolic and diastolic dysfunction, has a complex etiology, including the accumulation of MG-formed advanced glycation end products (AGEs). Methylglyoxal is detoxified by the activities of the enzymes glyoxalase 1 (GLO1) and glyoxalase 2. We have developed a mouse line that carries a transgene encoding human GLO1 (hGlo1) under the control of the preproendothelin promoter. The hGlo1 transgene has been shown to reduce MG-derived AGEs in tissues of streptozotocin (STZ)-induced hyperglycemic mice. We have also shown that over-expression of hGlo1, solely in the bone marrow, can rescue defective post-ischemic revascularization in STZ-treated mice. In this present study, the hGlo1 mice have been used to test the hypothesis that reduced MG levels can offset the development of diabetic cardiomyopathy. Diabetes was induced by intraperitoneal injection of STZ; 4 and 8 weeks post-STZ treatment, echocardiography of the wild type (WT) diabetic group showed systolic dysfunction. At 4 weeks of hyperglycemia, the ejection fraction (EF) was 54% and fraction shortening (FS) 37%. In contrast, cardiac function in the GLO1 diabetic mice as well as non-diabetic controls remained normal over time. Both the EF and FS were significantly lower in WT diabetic mice at 4 weeks post STZ-treatment compared to the control mice (p=0.02 and p=0.04, respectively). Western blots of heart tissue collected after 8 weeks of diabetes showed a significant increase in the expression of RAGE (receptor for AGE) in WT diabetic mice compared to other groups (p=0.038). Heart tissue collected from GLO1 diabetic and non-diabetic mice had increased GLO1 activity by 1.7-fold compared to the non transgenic mice. These results suggest that MG contributes to the development of diabetic cardiomyopathy and that reducing methylglyoxal levels could be a potential therapeutic target for prevention.
- © 2013 by American Heart Association, Inc.