Monoamine oxidase inhibition improves vascular function and reduces oxidative stress in rats with lipopolysaccharide-induced inflammation.

Oxidative stress and vascular inflammation are the two major pathomechanisms that contribute to the progression of both cardiovascular and metabolic diseases. We have previously demonstrated that monoamine oxidases (MAOs), mitochondrial enzymes with two isoforms (A and B), are contributors to the endothelial dysfunction associated with inflammation in mice. The present study was purported to assess the effects of MAOs on endothelial dysfunction in rats with lipopolysaccharide (LPS)-induced acute inflammation. To this aim, aortas harvested from rats treated or not with a single dose of LPS were used for organ-bath studies of vascular reactivity and H2O2 production assessment in the presence vs. absence of MAO inhibitors. Our results demonstrate that MAO-A and B isoforms are induced in the rat vascular system after LPS administration. Both reversible and irreversible MAOs inhibition improved vascular function and reduced oxidative stress. In conclusion, MAOs are contributors to the occurrence of endothelial dysfunction in the rat model of LPS-induced acute inflammation. MAO inhibition may become a viable therapeutic strategy for the treatment of cardiometabolic disease.