title: [Circadian variations in proinflammatory cytokine concentrations in acute myocardial infarction].
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
authors.affiliation: Servicio de Cardiología. Hospital Universitario Nuestra Señora de Candelaria. Santa Cruz de Tenerife. España.
authors.forename: Alberto
authors.initials: A
authors.lastname: Domínguez Rodríguez
authors.forename: Pedro
authors.initials: P
authors.lastname: Abreu González
authors.forename: Martín J
authors.initials: MJ
authors.lastname: García
authors.forename: Alejandro
authors.initials: A
authors.lastname: de la Rosa
authors.forename: Manuel
authors.initials: M
authors.lastname: Vargas
authors.forename: Francisco
authors.initials: F
authors.lastname: Marrero
mesh_terms: D000208:Acute Disease; D000368:Aged; D002940:Circadian Rhythm / Q000502:physiology*; D016207:Cytokines / Q000378:metabolism*; D005260:Female; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000378:metabolism*
chemical_list: D016207:Cytokines; D007375:Interleukin-1; D015850:Interleukin-6