A hypoxic inducible factor-1α hybrid enhances collateral development and reduces vascular leakage in diabetic rats
ABSTRACT Diabetes mellitus is a common comorbidity of atherosclerosis. Hypoxia-inducible factor-1 (HIF-1) is the master regulator of the angiogenic response to hypoxia.
We studied the effects of adenoviral vectors expressing a constitutively active HIF-1 alpha hybrid (Ad2/HIF-1 alpha/VP16) or vascular endothelial growth factor (Ad2/VEGF) on collateral development and vascular leakiness in a diabetic rat model of hindlimb ischemia.
After the removal of the right femoral artery, the mRNA levels of VEGF, angiopoietin-1 and angiopietin-4 in the calf muscles, as measured by Taqman reverse transcriptase-polymerase chain reaction, were transiently elevated in Zucker lean (ZL) but not Zucker diabetic fatty (ZDF) rats. The angiographic score, as determined by post-mortem angiography, was significantly lower in ZDF animals 35 days after surgery compared to their ZL counterparts. In separate animals, intramuscular injection of Ad2/HIF-1a/VP16 and Ad/2VEGF into the thigh muscles significantly increased the angiographic score and capillary density 21 and 35 days after the injection compared to Ad2/CMVEV (a vector expressing no transgene) or vehicle. After the injection of Ad2/CMVEV or vehicle, the Evans-blue dye content in the thigh muscles was significantly higher in ZDF rats than their ZL counterparts. Ad2/HIF-1 alpha/VP16 but not Ad2/VEGF reduced tissue Evans blue dye content.
The endogenous angiogenic response to ischemia was impaired in ZDF rats, possibly due to down-regulation of angiogenic factors. Ad2/HIF-1 alpha/VP16 enhanced collateral development and reduced vascular leakage in the ischemic hindlimb of ZDF rats indicating that hybrid HIF-1 alpha angiogenic therapy may be efficacious for peripheral vascular disease with a diabetic comorbidity.
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ABSTRACT: Hyperglycaemia and hypoxia play essential pathophysiological roles in diabetes. We determined whether hyperglycaemia influences endothelial cell growth under hypoxic conditions in vitro. Using a Ruskinn Invivo2 400 Hypoxia Workstation, bovine aortic endothelial cells (BAEC) were exposed to high glucose concentrations (25 mM glucose) under normoxic or hypoxic conditions before cell growth (balance of proliferation and apoptosis) was assessed by fluorescence-activated cell sorting (FACS) analysis, proliferating cell nuclear antigen (pCNA), Bcl-xL and caspase-3 protein expression and activity. Hypoxia increased hypoxia response element (HRE) transactivation and induced hypoxia-inducible factor-1α (HIF-1α) expression when compared to normoxic controls concomitant with a significant decrease in cell growth. High glucose (25 mM) concentrations attenuated HRE transactivation and HIF-1α protein expression while concurrently reducing hypoxia-induced changes in BAEC growth. Knockdown of HIF-1α expression significantly decreased hypoxia-induced changes in growth and attenuated the modulatory effects of glucose. These results provide evidence that hypoxia-induced control of BAEC growth can be altered by the presence of glucose via inhibition of HIF-1α expression and activation.Diabetes & Vascular Disease Research 05/2014; 11(4). DOI:10.1177/1479164114533356 · 3.04 Impact Factor
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ABSTRACT: After the onset of ischemia, cardiac or skeletal muscle undergoes a continuum of molecular, cellular, and extracellular responses that determine the function and the remodeling of the ischemic tissue. Hypoxia-related pathways, immunoinflammatory balance, circulating or local vascular progenitor cells, as well as changes in hemodynamical forces within vascular wall trigger all the processes regulating vascular homeostasis, including vasculogenesis, angiogenesis, arteriogenesis, and collateral growth, which act in concert to establish a functional vascular network in ischemic zones. In patients with ischemic diseases, most of the cellular (mainly those involving bone marrow-derived cells and local stem/progenitor cells) and molecular mechanisms involved in the activation of vessel growth and vascular remodeling are markedly impaired by the deleterious microenvironment characterized by fibrosis, inflammation, hypoperfusion, and inhibition of endogenous angiogenic and regenerative programs. Furthermore, cardiovascular risk factors, including diabetes, hypercholesterolemia, hypertension, diabetes, and aging, constitute a deleterious macroenvironment that participates to the abrogation of postischemic revascularization and tissue regeneration observed in these patient populations. Thus stimulation of vessel growth and/or remodeling has emerged as a new therapeutic option in patients with ischemic diseases. Many strategies of therapeutic revascularization, based on the administration of growth factors or stem/progenitor cells from diverse sources, have been proposed and are currently tested in patients with peripheral arterial disease or cardiac diseases. This review provides an overview from our current knowledge regarding molecular and cellular mechanisms involved in postischemic revascularization, as well as advances in the clinical application of such strategies of therapeutic revascularization.Physiological Reviews 10/2013; 93(4):1743-802. DOI:10.1152/physrev.00006.2013 · 29.04 Impact Factor
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ABSTRACT: Objective. To investigate the effect of beraprost sodium (BPS) on diabetic cardiomyopathy and the underlying mechanism. Methods. A total of 40 Sprague Dawley rats were randomly divided into the normal control group (N = 10) and the model group (N = 30). The model group was fed a high-fat diet followed by a one-time dose of streptozotocin (STZ) to establish the diabetes mellitus model. After that, rats were randomly divided into two groups with or without BPS intervention. After 8 weeks, we explored the role of the p38 MAPK signaling pathway in inflammation, oxidative stress, cardiac morphology, and myocardial apoptosis. Results. Compared with control, the ratio of heart-weight to body-weight and the serum levels of SOD and GSH in the BPS group significantly increased, the expression of p38 MAPK, the serum levels of MDA, TGF-β1, TNF-α, HIF-1α, MMP-9, caspase-3, BNP, ANP, and heart Bax expression significantly decreased, and heart Bcl-2 expression significantly increased. H&E staining in diabetic rats showed the cardiac muscle fibers derangement, the widening gap, the pyknotic and fragmented nuclei, and more apoptosis. Conclusions. BPS effectively showed protective effects on diabetic myocardial cells, possibly through the inhibition of p38 MAPK signaling pathway.International Journal of Endocrinology 11/2014; 2014:901437. DOI:10.1155/2014/901437 · 1.52 Impact Factor