The evolving concept of physiological ischemia training vs. ischemia preconditioning

Ischemic heart diseases are the leading cause of death with increasing numbers of patients worldwide. Despite advances in revascularization techniques, angiogenic therapies remain highly attractive. Physiological ischemia train- ing, which is first proposed in our laboratory, refers to reversible ischemia training of normal skeletal muscles by using a tourniquet or isometric contraction to cause physiologic ischemia for about 4 weeks for the sake of triggering mole- cular and cellular mechanisms to promote angiogenesis and formation of collateral vessels and protect remote ische- mia areas. Physiological ischemia training therapy augments angiogenesis in the ischemic myocardium by inducing differential expression of proteins involved in energy metabolism, cell migration, protein folding, and generation. It upregulates the expressions of vascular endothelial growth factor, and induces angiogenesis, protects the myocardium when infarction occurs by increasing circulating endothelial progenitor cells and enhancing their migration, which is in accordance with physical training in heart disease rehabilitation. These findings may lead to a new approach of ther- apeutic angiogenesis for patients with ischemic heart diseases. On the basis of the promising results in animal studies, studies were also conducted in patients with coronary artery disease without any adverse effect in vivo, indicating that physiological ischemia training therapy is a safe, effective and non-invasive angiogenic approach for cardiovascular rehabilitation. Preconditioning is considered to be the most protective intervention against myocardial ischemia-reper- fusion injury to date. Physiological ischemia training is different from preconditioning. This review summarizes the preclinical and clinical data of physiological ischemia training and its difference from preconditioning.

Independent and Combined Associations of Sleep Duration, Bedtime, and Polygenic Risk Score with the Risk of Hearing Loss among Middle-Aged and Old Chinese: The Dongfeng–Tongji Cohort Study

Evidence available on the independent and combined associations of sleep duration,bedtime,and genetic predisposition with hearing loss was lacking.The present study included 15,827 participants from the Dongfeng–Tongji cohort study.Genetic risk was characterized by polygenic risk score(PRS)based on 37 genetic loci related to hearing loss.We conducted multivariate logistic regression models to assess the odds ratio(OR)for hearing loss with sleep duration and bedtime,as well as the joint association and interaction with PRS.Results showed that hearing loss was independently associated with sleeping≥9 h/night compared to the recommended 7 to<8 h/night,and with bedtime≤9:00 p.m.and>9:00 p.m.to 10:00 p.m.compared to those with bedtime>10:00 p.m.to 11:00 p.m.,with estimated ORs of 1.25,1.27,and 1.16,respectively.