The endothelial cells lining blood vessels form a tight barrier, which is weakened (permeabilized) by inflammation. Vitamin C tightens the endothelial barrier and maintains its integrity during inflammation, but the mechanisms for vitamin C action remain unclear.
James May , M.D., and colleagues explored whether and how vitamin C can stabilize the endothelial barrier using human umbilical vein endothelial cells. They reported that vitamin C prevented increased permeability induced by thrombin, an inflammatory stimulus.
They demonstrated that vitamin C preserves levels of the signaling molecule cAMP, which works to maintain the actin cytoskeleton and prevent the formation of stress fibers that compromise the endothelial barrier. Preservation of cAMP was dependent on both the production of nitric oxide and cGMP.
The findings demonstrate how vitamin C protects the endothelial barrier during inflammation and suggest that dietary vitamin C may promote vascular integrity in patients with inflammatory diseases.