Protection of coronary endothelial cells from cigarette smoke-induced oxidative stress by a new MnII-containing polyamine-polycarboxilate scavenger of superoxide anion

Oxidative stress plays a major role in cardiovascular injury and dysfunction induced by cigarette smoke. Smoke-borne pro-oxidants impair endothelial function and predispose to thrombosis, inflammation and atherosclerosis. This in vitro study evaluates whether MnII(4,10-dimethyl-1,4,7,10-tetraazacyclododecane-1,7-diacetate).2H2O (MnII(Me2DO2A)), a polyamine–polycarboxilate, MnII-containing O2− scavenger, has a direct protective action on guinea pig coronary endothelial (GPCE) cells exposed to cigarette smoke extracts (CSE).MnII(Me2DO2A) (1–10 μmol/l) was added to the culture medium together with CSE and maintained for 4 h. In parallel experiments, the inactive congener ZnII(Me2DO2A), in which ZnII replaced the functional MnII center in the same organic scaffold, was used as negative control.MnII(Me2DO2A), mostly at the higher doses (5 and 10 μmol/l), significantly increased GPCE cell viability (trypan blue assay), improved mitochondrial activity (MTT test, mitochondrial membrane potential Δψ), reduced cellular apoptosis (mPTP, caspase-3 activity, TUNEL assay), decreased intracellular ROS levels (H2DCFDA), lipoperoxidation (BODIPY 581/591) and decreased protein nitrosylation. Of note, ZnII(Me2DO2A) did not preserve cell viability. These findings suggest that MnII(Me2DO2A) is a promising O2− scavenging compound able to protect from cigarette smoke-induced oxidative cell injury. In perspective, should its efficacy be confirmed in future in vivo studies, this molecule might represent a therapeutic or preventive drug to counteract cigarette smoke toxicity.

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