Endothelial and vascular smooth muscle cell dysfunction mediated by cyclophylin A and the atheroprotective effects of melatonin

AIMS: This study evaluated the role of cyclophilin A (CyPA) in early phase of atherosclerosis and also examined the atheroprotective effects of melatonin due to its antioxidant properties. MAIN METHODS: APOE null mice at 6 and 15weeks of age were treated with melatonin at a dose of 0.1mg/kg/day or 10mg/kg/day. We evaluated both histopathological alterations in endothelial and vascular smooth muscle cells by CyPA and rolling mononuclear cell expression during the early phase of atherosclerosis development. KEY FINDINGS: Our study showed that CyPA expression increases and may modulate inflammatory cell adhesion and interleukin-6 expression inducing vascular smooth muscle cell migration and inflammatory cell extravasation in a time-dependent manner. Moreover, we observed an indirect atheroprotective effect of melatonin on vascular injury; it inhibited CyPA mediated inflammatory cell extravasation and oxidative stress. SIGNIFICANCE: The melatonin treatment may represent a new atheroprotective approach that contributes to reducing the early phase of atherosclerosis involving the rolling of monocytes, their passage to subendothelial space and inhibition of CyPA expression.