Perinatal Tissues to Study In vitro Mechanisms of Inflammation and Angiogenesis: Novel Insight on Diabetic Non-Healing Wound

Impaired wound healing is one of the main diabetes mellitus complications associated to several detrimental features such as the establishment of a pro-inflammatory and pro-oxidative environment together with reduced peripheral blood flow and angiogenesis. Unfortunately, effective therapies are currently lacking. Recently, among perinatal derivatives, Amniotic Membrane (AM) has demonstrated encouraging results in wound management. Therefore, here the potential effect of AM on endothelial cells isolated from the umbilical cord vein of gestational diabetes affected women (GD-HUVEC), have been investigated. Indeed, GD-HUVEC have shown a pro-inflammatory phenotype and lower vessel formation on Matrigel compared to control HUVEC (C-HUVEC), thus representing a valuable model for studying the anti-inflammatory role of AM and neovascularization of chronic non-healing wounds. The anti-inflammatory properties of AM have been assessed in Tumor Necrosis Factor- (TNF- ) pre-stimulated cells using a monocyte-endothelium adhesion assay and evaluating vascular adhesion molecules expression and membrane exposure, together with Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-kB) expression and nuclear translocation and Nitric Oxide (NO) bioavailability. Moreover, tube formation ability was studied in AM-treated C- and GD-HUVEC. The findings indicated that AM significantly reduced TNF- stimulated monocyte-endothelium interaction and membrane exposure of the Vascular cell and Intracellular adhesion molecules (VCAM-1 and ICAM-1, respectively) in both C- and GD-HUVEC. Strikingly, AM treatment significantly improved tube-like structure interconnections in GD-HUVEC. Overall, these results indicate that, in our in vitro cell model, AM attenuates TNF- -increased inflammation and improves angiogenesis, possibly through the modulation of NO bioavailability, which plays a key role in the vascular homeostasis balance. This study suggests that AM chronic wound healing improvement may be due to endothelial proper management, therefore explaining its clinical benefit on diabetic foot ulcers.