Abstract: The PIs of this application have developed techniques for producing and studying atherosclerosis using funds from the first AMDCC program. Specifically, we have found that streptozotocin-treated mice develop increased atherosclerosis in the presence of a transgene for human aldose reductase (hAR). We have also noted that hearts from these mice have areas of cardiac apoptosis. In addition, we have developed novel methods to study atherosclerosis regression that can be applied to studies of lesions in control and diabetic mice. Aim 1 To create new mouse models of diabetic cardiovascular disease: We propose to create two new genetically altered mice. Aim 1a is to use the tet on system to allow expression of hAR in a time dependent manner. This system will allow us to test whether hAR expression in established lesions alters plaque morphology. These animals can also be used to produce tissue specific expression of hAR. Aim 1b is to produce mice with expression of hAR in cardiomyocytes. These mice, we hypothesize, will develop cardiomyopathy with diabetes. Aim 2 To study the development of vascular lesions in diabetic mice: Mild diabetes due to deficiency of Pdx1 or high fat diets did not alter atherosclerosis in Ldlr-/- mice. In addition, Pdx1 did not affect regression after transplant of arteries containing atherosclerosis. We will use two additional methods to generate hyperglycemia, Akita and high fat diets on the FVB background, in Ldlr-/- mice q hAR. Increased vascular disease in STZ-treated hAR mice could result from greater monocyte/macrophage accumulation in lesions, or could be secondary to a defect in lesion regression. Both processes will be studied in vivo and mechanistic information obtained by studying gene and protein expression.