Premium
Knockout of TSP‐1 Prevents Hyperglycemia‐induced Atherosclerosis in STZ‐treated ApoE −/− Mice
Author(s) -
Ganguly Rituparna,
Sahu Soumyadip,
Raman Priya
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.956.3
Subject(s) - medicine , apolipoprotein e , diabetes mellitus , endocrinology , streptozotocin , h&e stain , disease , immunohistochemistry
Atherosclerosis, a macrovascular disease is responsible for ~70–80% long term deaths in diabetic patients. Several clinical studies and trials as well as recent animal studies have identified hyperglycemia, hallmark of Type 1 and Type 2 diabetes, as a critical risk factor for atherosclerotic complications associated with diabetes. Thrombospondin‐1 (TSP‐1) is a proatherogenic and anti‐angiogenic ‘matricellular’ protein genetically associated with development of atherosclerosis, coronary artery disease and myocardial infarction. TSP‐1 level is significantly increased in diabetic patients, diabetic animal models and glucose‐stimulated vascular cells (endothelial cells, vascular smooth muscle cells, fibroblasts) in vitro . Previous reports, including earlier evidence from our laboratory, suggest TSP‐1 as a potential link between hyperglycemia and accelerated atherogenesis in diabetics. We showed earlier that in STZ‐induced hyperglycemic ApoE −/− mice, the micronutrient chromium picolinate in vivo attenuates development of atherosclerotic lesions concomitant to downregulation of TSP1 expression in the aortic vessels. The goal of the current study was to investigate a direct role of TSP‐1 in hyperglycemia‐induced atherosclerosis. We generated TSP1 −/− /ApoE −/− double knockout mice by crossing TSP1 −/− mice with atherosclerotic ApoE −/− mice, both being in C57BL/6J background. Hyperglycemia (blood glucose>250mg/dl) was induced in six weeks old male ApoE −/− mice and TSP1 −/− /ApoE −/− double knockout mice via intraperitoneal injection of 50 mg/kg/day of Streptozotocin (STZ) or sodium citrate buffer (vehicle) for 5 consecutive days. At endpoint, mice (18 wks. of age) were harvested for atherosclerotic lesion analyses. Specifically, Oil‐Red‐O and Hematoxylin‐eosin staining of the aortic root area showed a significant reduction in lipid laden atherosclerotic lesions (~2.4 fold) and intimal thickening (~32%) in STZ‐induced hyperglycemic TSP1 −/− /ApoE −/− mice compared to STZ‐treated ApoE −/− mice. Characterization of lesion cellularity by immunostaining for PCNA (proliferating cell nuclear antigen) and alpha‐SMA (alpha smooth muscle actin) revealed reduction in PCNA staining (~33%) and vascular smooth muscle cell abundance (~24%) in hyperglycemic TSP1 −/− /ApoE −/− mice compared to hyperglycemic ApoE −/− mice. Further, atherosclerotic lesions in the aortic sinus of STZ‐treated hyperglycemic TSP1 −/− /ApoE −/− mice showed a significant reduction in both macrophage content and collagen accumulation (~68%) as compared to the STZ treated hyperglycemic ApoE −/− mice. Together these data clearly demonstrate that knockout of TSP‐1 in ApoE −/− mice protects against hyperglycemia‐induced atherosclerosis, suggesting TSP‐1 as a potential therapeutic target in diabetic macrovascular disease. Support or Funding Information Supported by Diabetes Action Research and Education Foundation (DAREF) and NEOMED start‐up funds.