Cold wave-induced stroke: the roles of renin-angiotensin system and matrix metalloproteinase-9

Epidemiological studies and clinical observations have indicated that cold temperature can trigger the occurrence of stroke in individuals at high risk. However, the underlying mechanisms are still unknown. Matrix metalloproteinase-9 (MMP-9) has been found to be associated with the formation, progression and rupture of atherosclerotic plaques and cerebral aneurysms, which is the pathological basis of stroke. Cold temperature activates renin-angiotensin system (RAS) in circulation and tissue. Angiotensin Ⅱ has been implicated in the inducing MMP-9 expression and activation. An increase of MMP-9 may facilitate destabilization and rupture of atherosclerotic plaques or cerebral aneurysms, resulting in the occurrence of stroke. Key words: Stroke; Cold Temperature; Seasons; Renin-Angiotensin System; Matrix Metalloproteinase 9; Time Factors; Risk Factors