Rescue of Diabetes-Related Impairment of Angiogenesis by Intramuscular Gene Therapy with Adeno-VEGF

Abstract

Diabetes is a major risk factor for coronary and peripheral artery diseases. Although diabetic patients often present with advanced forms of these diseases, it is not known whether the compensatory mechanisms to vascular ischemia are affected in this condition. Accordingly, we sought to determine whether diabetes could: 1) impair the development of new collateral vessel formation in response to tissue ischemia and 2) inhibit cytokine-induced therapeutic neovascularization. Hindlimb ischemia was created by femoral artery ligation in nonobese diabetic mice (NOD mice, n = 20) and in control C57 mice (n = 20). Hindlimb perfusion was evaluated by serial laser Doppler studies after the surgery. In NOD mice, measurement of the Doppler flow ratio between the ischemic and the normal limb indicated that restoration of perfusion in the ischemic hindlimb was significantly impaired. At day 14 after surgery, Doppler flow ratio in the NOD mice was 0.49+/-0.04 versus 0.73+/-0.06 for the C57 mice (P< or =0.005). This impairment in blood flow recovery persisted throughout the duration of the study with Doppler flow ratio values at day 35 of 0.50+/-0.05 versus 0.90+/-0.07 in the NOD and C57 mice, respectively (P< or =0.001). CD31 immunostaining confirmed the laser Doppler data by showing a significant reduction in capillary density in the NOD mice at 35 days after surgery (302+/-4 capillaries/mm2 versus 782+/-78 in C57 mice (P< or =0.005). The reduction in neovascularization in the NOD mice was the result of a lower level of vascular endothelial growth factor (VEGF) in the ischemic tissues, as assessed by Northern blot, Western blot and immunohistochemistry. The central role of VEGF was confirmed by showing that normal levels of neovascularization (compared with C57) could be achieved in NOD mice that had been supplemented for this growth factor via intramuscular injection of an adenoviral vector encoding for VEGF. We conclude that 1) diabetes impairs endogenous neovascularization of ischemic tissues; 2) the impairment in new blood vessel formation results from reduced expression of VEGF; and 3) cytokine supplementation achieved by intramuscular adeno-VEGF gene transfer restores neovascularization in a mouse model of diabetes.

Adenovirus-mediated VEGF165 gene transfer enhances wound healing by promoting angiogenesis in CD1 diabetic mice

“…Altered wound repair is present in animal models of diabetes such as non-obese diabetic mice (NOD), db/db mice [15][16][17][18][19][20][21][22][23][24][25][26] and mice in which the diabetes was induced by treatment with streptozotocin. NOD mice develop a form of diabetes similar to human type-I insulin-dependent diabetes, also known as type 1 diabetes, that is an organspecific autoimmune disease resulting from the destruction of insulin-producing pancreatic ␤ cells.…”

“…Specifically, the impairment of angiogenesis was characterized by decreased capillary density and significant blood flow reduction in ischemic hindlimbs. 25 Diabetes in the C57 BL7KSJ db mouse (db/db mouse) is similar to maturity-onset diabetes (non-insulin-dependent diabetes mellitus, NIDDM) in humans and is characterized by obesity, infertility, hyperphagia and marked hyperglycemia. 26 Db/db mice show a significant reduction of VEGF mRNA expression during the healing process.…”

Discordant effects of a soluble VEGF receptor on wound healing and angiogenesis

“…1 Recent elaboration of mechanisms regulating angiogenesis has led to extensive efforts to identify and exploit potential agents stimulating angiogenesis under circumstances when the recruitment of new blood vessels is desired, for instance in coronary heart disease or peripheral arterial disease. [2][3][4][5][6][7] Conversely, the need for inhibitors of angiogenesis directed against angiogenesis in pathophysiological conditions such as tumor growth or proliferative diabetic retinopathy has arisen. 8 Among angiogenic growth factors, ligands for receptor tyrosine kinases (RTKs) such as vascular endothelial growth factor (VEGF) have been identified to play an essential role in vascular development.…”

Multi-scale Computational Models of Pro-angiogenic Treatments in Peripheral Arterial Disease

“…Significant, non-uniform collateralization in the hindlimb follows, resulting in large regions of perfused and unperfused muscle. 51 In addition, average capillary blood velocity is higher in rats that have undergone exercise training. 3 Thus, using empirical relationships for viscosity and hematocrit distribution, 25,46 and experimental measurements of blood oxygenation and velocity in ligated rat EDL 3,16,17,44,46 we simulated blood flow for perfused tissue and partially perfused tissue (where only half of the tissue arterioles have blood flow).…”

“…33,34 The most common animal model of PAD is surgical ligation of the femoral or iliac arteries. 3,29,44,47,51,53 Although this does not completely reproduce the symptoms of PAD, it has become a valuable tool and a useful correlation. Thus, the simulations we present here are for rat EDL muscle following femoral ligation.…”