Research Institute, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
J Surg Res. 2012 Jan;172(1):177-86. doi: 10.1016/j.jss.2010.08.016. Epub 2010 Sep 8.
Experimental evidence is accumulating to indicate that local acute vascular endothelial growth factor-165 (VEGF(165)) therapy is effective in attenuation of skin ischemia and increase in skin viability in rat skin flap surgery and the mechanism involves vasodilation induced by VEGF(165). So far, the vasodilator effect and mechanism of action of VEGF(165) have not been studied in human skin. The objective of this project is to test the hypothesis that VEGF(165) is also a potent vasodilator in human skin vasculature.
We used an established isolated perfused human skin flap model and pharmacologic probes to demonstrate that VEGF(165) is a potent vasodilator in human skin vasculature and the mechanism involves activation of receptors and postreceptor signaling pathway, which in turn stimulates local synthesis/release of endothelial vasodilators.
We observed that VEGF(165) induced a concentration-dependent vasorelaxation in human skin flaps preconstricted with norephinephrine (8 × 10(-7)M; n = 7) or endothelin-1 (3 × 10(-9)M; n = 6). The vasorelaxation potency of VEGF(165) (pD(2) = 12.02 ± 0.25; n = 7) was higher (P < 0.05) than that of acetylcholine (pD(2) = 6.76 ± 0.06; n = 5) in human skin flaps preconstricted with 8 x 10(-7)M of norepinephrine. Using pharmacologic probes, we also detected that the vasorelaxation effect of VEGF(165) in the isolated perfused human skin flaps (n = 4) was triggered by activation of VEGF receptor-2. Furthermore, the postreceptor signaling pathway involved activation of Src family tyrosine kinase, phospholipase C, protein kinase C, an increase in inositol 1,4,5-triphosphate activity, a release of the intracellular Ca(2+) store, and finally synthesis/release of the endothelial nitric oxide (eNO) and prostacyclin and eNO predominantly mediated the vasodilator effect of VEGF(165) in the effector mechanism.
These findings support our hypothesis that VEGF(165) is a potent vasodilator in human skin vasculature and also provide important insights into the clinical study of local acute VEGF(165) therapy for prevention/treatment of skin ischemia in skin flap surgery.
实验证据表明，局部急性血管内皮生长因子-165（VEGF(165)）治疗可有效减轻大鼠皮瓣手术中的皮肤缺血和增加皮肤存活率，其机制涉及 VEGF(165)诱导的血管舒张。到目前为止，VEGF(165)在人体皮肤中的血管舒张作用和作用机制尚未得到研究。本项目的目的是验证假设，即 VEGF(165)也是人体皮肤血管中的一种有效的血管舒张因子。
我们使用已建立的离体灌注人体皮瓣模型和药理学探针来证明 VEGF(165)是人体皮肤血管中的一种有效的血管舒张因子，其机制涉及受体的激活和受体后信号通路，进而刺激内皮血管舒张因子的局部合成/释放。
我们观察到，VEGF(165)在预先用去甲肾上腺素（8×10(-7)M；n=7）或内皮素-1（3×10(-9)M；n=6）预收缩的人体皮瓣中诱导浓度依赖性的血管舒张。VEGF(165)的血管舒张作用强度（pD2=12.02±0.25；n=7）高于预先用 8 x 10(-7)M 去甲肾上腺素预收缩的人体皮瓣中乙酰胆碱（pD2=6.76±0.06；n=5）的血管舒张作用强度（P<0.05）。使用药理学探针，我们还检测到，在离体灌注的人体皮瓣中（n=4），VEGF(165)的血管舒张作用是通过激活 VEGF 受体-2触发的。此外，受体后信号通路涉及Src 家族酪氨酸激酶、磷脂酶 C、蛋白激酶 C 的激活、三磷酸肌醇（IP3）活性的增加、细胞内钙库的释放，最终合成/释放内皮一氧化氮（eNO）和前列环素，eNO 主要介导 VEGF(165)在效应机制中的血管舒张作用。
这些发现支持我们的假设，即 VEGF(165)是人体皮肤血管中的一种有效的血管舒张因子，也为局部急性 VEGF(165)治疗预防/治疗皮瓣手术中皮肤缺血的临床研究提供了重要的见解。
