2 One potential explanation is that an inappropriate elevation of sheer stress during the inactive/sleep phase (ie, as observed in nondipping hypertensives) may contribute to a pathological response, whereas appropriate anticipation of temporal changes in sheer stress results in a physiological response.Ĭentral to the concept of biological anticipation are 2 fundamental criteria. In contrast, a persistent elevation of sheer stress results in a pathological hypertrophic response. 1 Increased activity (such as exercise) results in a physiological growth (hypertrophy) of the myocardium. Alterations in sheer stress occur on a daily basis within a physiological range, peaking during the active/awake period, a time at which physical activity is typically elevated. One cardiovascular-relevant hypothetical example is illustrated by myocardial responsiveness to changes in pressure/sheer stress. In the latter case, one might envision priming of a distinct branch of a signal transduction pathway in a temporal manner, to ensure an appropriate cellular response to a predictable, recurring stimulus/stress. However, the ability to prepare for an event before it occurs is critical for numerous aspects of life, whether it be preparation for a newborn child, the arrival of a food source, or perhaps at the cellular level the binding of a hormone to its receptor. Typically, a researcher might consider a cell/system that responds to a stimulus based solely on its initiation (ie, in the absence of any form of priming). The key to this unique selective advantage is anticipation.
This information is critical to ensure appropriate and rapid responses are achieved in a temporally correct manner. Knowing the time of day presents a selective advantage at multiple biological tiers, including cellular, tissue, and whole organism. The purpose of this review is therefore to highlight recent advances regarding the roles of the cardiomyocyte circadian clock in both myocardial physiology and pathophysiology (ie, health and disease). Following an appreciation of its physiological roles, the cardiomyocyte circadian clock has recently been linked to the pathogenesis of heart disease in response to adverse stresses, such as ischemia/reperfusion, in animal models. Recent molecular- and genetic-based studies suggest that the cardiomyocyte circadian clock influences multiple myocardial processes, including transcription, signaling, growth, metabolism, and contractile function. This cell autonomous mechanism has been identified within all cardiovascular-relevant cell types, including cardiomyocytes. Time-of-day–dependent synchronization of organisms with their environment is mediated by circadian clocks. Customer Service and Ordering InformationĪbstract: Circadian misalignment has been implicated in the development of obesity, diabetes mellitus, and cardiovascular disease.Stroke: Vascular and Interventional Neurology.Journal of the American Heart Association (JAHA).
Circ: Cardiovascular Quality & Outcomes.Arteriosclerosis, Thrombosis, and Vascular Biology (ATVB).
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