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Pain is not a symptom that exists alone, but whether chronic pain enhances susceptibility to myocardial ischemia/reperfusion (MI/R) injury and the underlying mechanisms remain unknown. Reactive aldehydes contribute to pain pathologies and cardiac injury, suggesting that aldehyde dehydrogenase (ALDH2), which detoxifies aldehydes, may regulate chronic pain related MI/R injury. The aim of this study was to investigate the roles of ALDH2 in chronic pain related MI/R injury and to elucidate the underlying mechanisms.
In this study, chronic neuropathic pain was induced by chronic compression of the dorsal root ganglion (CCD). CCD for 2 weeks, ALDH2 KO or wild-type (WT) littermates were subjected to in vivo MI/R.
CCD-WT mice exhibited heightened nociception and correlated with circulating aldehyde (4-HNE) accumulation and cardiac protein carbonylation. CCD induced 4-HNE overload provoked cardiac SIRT1 carbonylative inactivation and impairment the cardioprotection of LKB1-mediated AMPK activation, which resulting in enhanced MI/R injury and higher mortality compare with pain free WT mice. Chronic neuropathic pain enhanced susceptibility to MI/R injury was further exacerbated by ALDH2 deficiency in which associated with more impaired SIRT1-LKB1-AMPK signaling. However, treatment of CCD-WT mice with ALDH2-selective activator (Alda-1) or cardiac specific ALDH2 upregulation by AAV9-cTNT-mediated gene delivery significantly reduced chronic neuropathic pain-induced SIRT1 carbonylative inactivation and decreased MI/R injury (minor infarct size, less apoptosis, and elevated cardiac function).
These results strongly suggest that elevated reactive aldehyde concentration, like that observed in the presence of chronic pain, may render cardiomyocytes more susceptible to MI/R injury by SIRT1 carbonylative inactivation and impairment the cardioprotection of LKB1-mediated AMPK activation. ALDH2 activation blocked reactive aldehyde overproduction induced carbonyl stress and attenuated myocardial ischemic vulnerability in chronic pain individual.