414 - Deletion of TXNIP Mitigates High Fat Diet-Impaired Blood Flow and Inflammation in a Model of Critical Limb Ischemia

Abstract

Introduction Previous work demonstrated that silencing thioredoxin-interacting protein (TXNIP) prevents diabetes-impaired vascular recovery in diabetic model. Here, we examine the impact of high fat diet (HFD) on impaired vascular recovery and possible protective roles of deleting TXNIP. We hypothesize that deletion of TXNIP prevents HFD-mediated nitrative stress, inflammation and preserves vascular recovery. Methods Wild type mice (WT, C57Bl/6) and TXNIP knockout mice (TKO) were fed either normal chow (WT-ND and TKO-ND) or 60% fat diet (WT-HFD and TKO-HFD). After 4 weeks of HFD, unilateral hind limb ischemia was performed and blood flow was measured using Laser doppler scanner at baseline and then weekly for additional 3 weeks. Vascular density, nitrative stress, infiltration of CD68-macrophages, and expression of inflammasome, VEGF, VEGF receptor-2 were examined by slot blot, Western blot and immunohistochemistry. Results HFD increased total body weight and induced insulin resistance in both WT and TKO mice. HFD significantly impaired blood flow and vascular density (CD31 labeled) in skeletal muscle of WT mice compared to ND but not in TKO. HFD and ischemia induced tyrosine nitration, cleaved caspase-1 and IL-1 and infiltration of CD68 in skeletal muscle from WT but not from TKO. HFD or ischemia had no effect on VEGF or VEGFR2 levels in all groups. Under ND, ischemia induced phosphorylation of VEGFR2 in both WT and TKO. HFD impaired VEGFR2 activation in WT but not in TKO. Conclusion Similar to diabetes, HFD-induced obesity can compromise vascular recovery in response to ischemic insult. The mechanism involves increased nitrative stress and impaired VEGFR2 activation. Deletion of TXNIP reduced nitrative stress and restored VEGFR2 signaling and blood flow in HFD. Targeting TXNIP can provide potential therapeutic target in obesity-induced vascular complication.