[Circadian variations in proinflammatory cytokine concentrations in acute myocardial infarction]

Abstract

Introduction and objectives: The concentration of certain proinflammatory cytokines has been found to be elevated in patients with acute coronary syndrome. Many studies have shown that coronary ischemic accidents do not show a uniform distribution throughout the day, but instead exhibit rhythmic variations. The objective of this study is to determine whether there is a circadian pattern of variation in the concentrations of proinflammatory cytokines in patients with acute myocardial infarction.

Patients and method: The sample included 40 patients with acute myocardial infarction and 40 controls. Levels of interleukin 6 and 1 beta were determined in the first 24 hours after the acute coronary ischemic episode. Blood samples were extracted at 3:00 a.m. (period of darkness) and at 10:00 a.m. (period of daylight).

Results: Both groups were similar in age, sex distribution, and coronary risk factors. Interleukin 6 levels showed a significant variation between daylight and nighttime concentrations in patients with acute myocardial infarction and controls (41.93 5.90/100.39 13.60 vs 25.76 4.45/52.67 7.73 pg/ml). However, interleukin 6 concentrations were higher in the acute myocardial infarction group than in the control group. Interleukin 1 beta concentrations did not vary between daylight and darkness.

Conclusions: In both the control group and acute myocardial infarction group, interleukin 6 concentrations varied between daylight and darkness. Patients with acute myocardial infarction shown a higher concentration of interleukin 6 secondary to the physiological response to tissue damage. Circadian variations can affect the measurements obtained for different physiological and biochemical parameters.