Recovery from hind limb ischemia is less effective in type 2 than in type 1 diabetic mice: Roles of endothelial nitric oxide synthase and endothelial progenitor cells

Abstract

Objective We sought to directly compare the effects of type 1 and type 2 diabetes on post-ischemic neovascularization and evaluate the mechanisms underlying differences between these groups. We tested the hypothesis that type 2 diabetic mice have a greater reduction in eNOS expression, greater increase in oxidative stress, and reduced arteriogenesis and angiogenesis resulting is less complete blood flow recovery than type 1 diabetic mice after induction of hindlimb ischemia. Methods Hindlimb ischemia was generated by femoral artery excision in streptozotocin-treated mice (model of type 1 diabetes), in db/db mice (model of type 2 diabetes), and in control (C57BL/6) mice. Dependent variables included markers of arteriogenesis and angiogenesis, as well as eNOS and markers of oxidative stress. Results Post-ischemia recovery of hindlimb perfusion was significantly less in type 2 than in type 1 diabetic mice; however, neither diabetic group demonstrated a significant increase in collateral artery diameter or collateral artery angioscore in the ischemic hindlimb. The capillary/myofiber ratio in the gastrocnemius muscle decreased in response to ischemia in control or type 1 diabetic mice, but remained the same in type 2 diabetic mice. Gastrocnemius muscle eNOS expression was lower in type 1 and 2 diabetic mice than in control mice; this expression decreased after induction of ischemia in type 2, but not type 1 diabetic mice. The percentage of endothelial progenitor cells (EPC) in peripheral blood failed to increase in either diabetic group after induction of ischemia, whereas this variable significantly increased in the control group in response to ischemia. EPC eNOS expression decreased after induction of ischemia in type 1, but not type 2 diabetic mice. EPC nitrotyrosine accumulation increased after induction of ischemia in type 2, but not type 1 diabetic mice. EPC migration in response to VEGF was reduced in type 1 and type 2 diabetic mice than in control mice. EPC incorporation into tubular structures was less effective in type 2 diabetic mice. Extensive fatty infiltration was present in ischemic muscle of type 2, but not type 1 diabetic mice. Conclusion We conclude that type 2 diabetic mice displayed a significantly less effective response to hindlimb ischemia than type 1 diabetic mice.

Cell Therapy and Critical Limb Ischemia: Evidence and Window of Opportunity in Obesity

“…Moreover, blood flow recovery was significantly less within type 2 diabetic mice compared to type 1 diabetic group [61]. These findings lend further support that other components including, hyperlipidemia and obesity, contribute to the observed impaired blood flow in type 2 diabetes compared to type-1.…”

Decelerated vascularization in tissue-engineered constructs in association with diabetes mellitus in vivo

“…The decrease in vascularization in diabetic animals is in line with other studies. Decelerated neoangiogenesis was reported in the ischemic hindlimb model of diabetic mice [11,37]. Thereby the possible mechanisms underlying impaired neovascularization in the diabetic organism are highly diverse.…”

“…A potential disadvantage could be the mutation of the leptin receptor. Leptin influences the proinflammatory immune response [35] as well as T-cell functions [36], which could affect angiogenesis [11,37].…”

“…Thereby the possible mechanisms underlying impaired neovascularization in the diabetic organism are highly diverse. Some of these mechanisms involve dysfunctioning and decrease in the number of endothelial progenitor cells [37]. Considerably increased differentiation of MSCs to adipocytes may be another reason for the reduced angiogenic capacity [37].…”

“…Some of these mechanisms involve dysfunctioning and decrease in the number of endothelial progenitor cells [37]. Considerably increased differentiation of MSCs to adipocytes may be another reason for the reduced angiogenic capacity [37]. Concerning diabetic microangiopathy the thickening of the basement membrane has to be considered [49].…”