Cardiac period 2 in myocardial ischemia: clinical implications of a light dependent protein.

Since the onset of myocardial infarction and stroke has distinct circadian patterns, the disruption of circadian rhythms may contribute to cardiovascular disease. A recent clinical study, reporting that the severity of myocardial ischemia depends on the time-of-day when ischemia occurs, highlights the impact of circadian rhythms on cardiovascular disease. In support of these observations, we found a cardioprotective role of the circadian rhythm protein Period 2 (Per2) during myocardial ischemia in mice. In these studies, exposing mice to daylight induced cardiac Per2, which was associated with protection from myocardial ischemia. Recent epidemiological studies found sunlight to be the dominant regulator of the human circadian rhythm, suggesting sunlight cycles are critical for maintaining a healthy cardiovascular system. However, the impact of circadian rhythm proteins on human disease remains unclear. This current review aims to make a link to current and future clinical practice by targeting cardiac Per2.