Background: Hyperglycemia (HG) and hyperinsulinemia (HI) may be factors enhancing the atherosclerotic complications of diabetes. We hypothesized that specific feeding of C57BL/6 apolipoprotein (apo) E-/- mice would alter their metabolic profiles and result in different degrees of neointima (NI) formation. We additionally hypothesized that an insulin-sensitizing agent (rosiglitazone) would prevent the development of type 2 diabetes and reduce neointima formation after carotid wire injury measured at 28 days.
Methods and results: Fasting glucose and insulin levels were elevated in the Western diet (WD) group, with a trend toward higher insulin levels and euglycemia in the fructose diet (FD)--fed mice. NI formation was exaggerated in the WD group compared with the FD or chow control groups. In the WD mice given rosiglitazone, glucose and insulin levels remained normal and NI formation was significantly reduced, as was NI macrophage content.
Conclusions: These findings demonstrate that apoE-/- mice fed a WD develop type 2 diabetes with an exaggerated NI response to injury. FD mice maintain euglycemia but develop insulin resistance, with an intermediate degree of NI growth compared with chow diet controls. Rosiglitazone prevents the development of hyperglycemia and hyperinsulinemia and normalizes the insulin release profile in the apoE-/-, WD-fed mouse and significantly reduces NI formation by 65% after carotid wire injury while reducing macrophage infiltration. These data support the hypothesis that type 2 diabetes in the setting of elevated cholesterol accelerates the response to vascular injury and suggest that agents that improve insulin sensitivity may have therapeutic value in reducing restenosis in type 2 diabetes.