Glycation cross-links inhibit matrix metalloproteinase-2 activation in vascular smooth muscle cells cultured on collagen lattice

Aims/hypothesis. Extracellular matrix glycation has been proposed to contri bute to the arterial stiffness observed in aging and diabetes. We examined whether matrix protein glycation regulates the proleolytic process through the manipulation of matrix metalloproteinases (MMPs) activation, using coll agen fibrils model. Methods. Vascular smooth muscle cells were cultured on control or glycated collagen fibrils. Matrix metal-loproteinase-2 activation and the production of tissue inhibitors of metalloproteinase (TIMPs) were measured in the con ditioned medium by using gelatin zymography and immunoblotting. Membrane ty pe 1 matrix metalloproteinase (MT1-MMP) expression was also measured in cel l lysates. Results. When smooth muscle cells were cultured on collagen fibrils, pro-MM P-2 processing to active form was observed in the conditioned medium in coi ncidence with the increased MT1-MMP expression and the suppressed TIMP-2 pr oduction. Culturing smooth muscle cells on glycated collagen fibrils inhibi ted MMP-2 activation and attenuated MT1-MMP expression without the alterati on of TIMP-2 production compared with control fibrils, indicating the possi ble mechanism of the suppression of MT1-MMP expression for the inhibition o f MMP-2 activation on glycated collagen fibrils. Inclusion of aminoguanidin e, an inhibitor of cross-linking formation, during collagen glycation resto red the MMP-2 activation, suggesting the role of cross-links on the inhibit ion of MMP-2 activation. Conclusion/interpretation. These observations suggest that glycation-induce d cross-linking formation in interstitial collagen contributes to arterial stiffness in aging and diabetes through the manipulation of matrix metallop roteinase activation along with the reduction of the susceptibility to prot eolytic enzymes.