Association of ischemia-modified albumin and melatonin in patients with ST-elevation myocardial infarction.
BACKGROUND
It has been proposed that reactive oxygen species (ROS) generated during myocardial ischemia-reperfusion modify the N-terminus of serum albumin resulting in ischemia-modified albumin (IMA) formation. Likewise, several recent publications provide evidence that melatonin, a circadian endogenously produced indolamine, is a direct scavenger of ROS. We sought to investigate the relationship between IMA and melatonin in ST- elevation myocardial infarction (STEMI).


METHODS
We compared IMA and melatonin levels in 27 patients with STEMI undergoing primary angioplasty and 20 age- and gender-matched healthy normal subjects. Blood samples were drawn at 02:00h (night period) and 09:00h (day period) while patients were resting, to assess IMA and melatonin.


RESULTS
In both groups, melatonin concentrations maintained a diurnal variation, but the difference between nocturnal and diurnal levels was less in the STEMI-patients than in the control group (p<0.001). In contrast to findings about melatonin, IMA levels showed no diurnal variations in control subjects. However, the STEMI group showed a diurnal fluctuation with significantly higher levels at 02:00h (p<0.01). The association between IMA and melatonin remained statistically significant after adjustment for cardiovascular risk factors. An inverse correlation between IMA and melatonin at 02:00h and at 09:00h was observed, with respective r-values of -0.42 (p<0.03) and -0.57 (p<0.002).


CONCLUSIONS
Circulating IMA is negatively correlated to melatonin in STEMI-patients. Our results suggest that melatonin might exert a beneficial effect as a radical scavenger in a human model of myocardial ischemia-reperfusion.
Department of Cardiology, Coronary Care Unit, University Hospital of Canarias, Ofra s/n La Cuesta E-38320, Tenerife, Spain. adrvdg@hotmail.com
Alberto
A
Dominguez-Rodriguez
Pedro
P
Abreu-Gonzalez
Martín J
MJ
Garcia-Gonzalez
Sima
S
Samimi-Fard
Russel J
RJ
Reiter
Juan Carlos
JC
Kaski
D000328:Adult; D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D002940:Circadian Rhythm; D004562:Electrocardiography; D005260:Female; D016166:Free Radical Scavengers / Q000097:blood; D006801:Humans; D016014:Linear Models; D008297:Male; D008550:Melatonin / Q000097:blood*; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000453:epidemiology / Q000378:metabolism* / Q000628:therapy; D015428:Myocardial Reperfusion Injury / Q000453:epidemiology / Q000378:metabolism* / Q000628:therapy; D017382:Reactive Oxygen Species / Q000378:metabolism; D012307:Risk Factors; D012709:Serum Albumin / Q000378:metabolism*
D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D012709:Serum Albumin; D008550:Melatonin