Different effects of catechin on angiogenesis and inflammation depending on VEGF levels.

Although physiological and pathological angiogenesis develop through similar processes, during pathological angiogenesis, proangiogenic factors are exacerbated. Polyphenols have been considered therapeutic tools for conditions exhibiting enhanced angiogenesis. However, the possibility that these compounds may also prevent vascularization in physiological situations is a major drawback for their use. The purpose of the current study was to investigate the effects of 0.1-100 μM catechin on endothelial cells (EC) and vascular smooth muscle cells (VSMC) regarding angiogenic and inflammatory processes. Catechin modulation of angiogenesis and inflammation was also evaluated in vivo using different models of angiogenesis: one physiological (skin wound-healing assay) and another one resembling pathological angiogenesis, exhibiting higher vascular endothelial growth factor (VEGF)-A stimulation (Matrigel plug assay). The in vitro results showed that 100 μM catechin increased viability (to 165.58% and to 165.34%) and decreased apoptosis (53.45% and 92.65%) and proliferation (33.19% and 23.36%) of EC and VSMC, respectively. Catechin affected migration and invasion, tending to increase both in EC and decreasing them in VSMC; however, it did not change sprouting angiogenesis. Nevertheless, catechin diminished in vitro inflammatory modulators such as tumor necrosis factor α (58.66% for human umbilical vein endothelial cells and 85.46% for human aortic smooth muscle cells) and nuclear factor kappa-B (38.43% for VSMC). The in vivo results demonstrated that catechin did not change angiogenesis and inflammation in skin wound-healing model and substantially decreased these processes in Matrigel plug assay. Altogether, the current study showed that catechin has different effects in angiogenesis and inflammation depending on VEGF-A levels. The absence of adverse effects in mature vasculature favors catechin potential use against pathological situations where angiogenesis is stimulated.