Angiogenesis and inflammation signaling are targets of beer polyphenols on vascular cells

Emerging evidence indicates that chronic inflammation and oxidative stress cluster together with angiogenic imbalance in a wide range of pathologies. In general, natural polyphenols present health-protective properties, which are likely attributed to their effect on oxidative stress and inflammation. Hops used in beer production are a source of polyphenols such as xanthohumol (XN), and its metabolites isoxanthohumol (IXN) and phytoestrogen 8-prenylnaringenin (8PN). Our study aimed to evaluate XN, IXN, and 8PN effects on angiogenesis and inflammation processes. Opposite in vitro effects were observed between 8PN, stimulating endothelial and smooth muscle cell (SMC) growth, motility, invasion and capillary-like structures formation, and XN and IXN, which inhibited them. Mouse matrigel plug and rat skin wound-healing assays confirmed that XN and IXN treatments reduced vessel number as well as serum macrophage enzymatic activity, whereas 8PN increased blood vessels formation in both assays and enzyme activity in the wound-healing assay. A similar profile was found for serum inflammatory interleukin-1β quantification, in the wound-healing assay. Our data indicate that whereas 8PN stimulates angiogenesis, XN and IXN manifested anti-angiogenic and anti-inflammatory effects in identical conditions. These findings suggest that the effects observed for individual compounds on vascular wall cells must be carefully taken into account, as these polyphenols are metabolized after in vivo administration. The modulation of SMC proliferation and migration is also of special relevance, given the role of these cells in many pathological conditions. Furthermore, these results may provide clues for developing useful therapeutic agents against inflammation- and angiogenesis-associated pathologies.