Cystatin C levels are decreased in acute myocardial infarction: effect of cystatin C G73A gene polymorphism on plasma levels.
BACKGROUND
Cystatin C is the most abundant protease inhibitor in the plasma. Low plasma levels have been found in patients with aortic aneurysms and they seem correlated with the extension of the aortic lesions in early aneurysms detected by ultrasonography.


METHODS
In this study, plasma levels of cystatin C have been investigated in patients with acute myocardial infarction (AMI), unstable angina and controls. The effect on plasma levels of the G73A polymorphism of the CST3 gene has been also evaluated.


RESULTS
Patients with acute myocardial infarction showed significantly lower levels of cystatin C compared to unstable angina and controls, but levels were nearly normal in a week after the acute event. The genotype distribution of the G73A polymorphism was not different among the groups. Nevertheless, cystatin C levels decreased proportionally with the number of A alleles. Cystatin C levels were positively correlated with age, triglyceride/HDL cholesterol ratio and creatinine, and negatively with HDL cholesterol and the number of A alleles. All variables, but not HDL cholesterol, were independently correlated in a multivariate analysis.


CONCLUSIONS
Cystatin C is decreased in acute myocardial infarction. It is still not clear whether lower cystatin C levels are causally linked to the acute event or just represent a negative acute phase response. The CST3 gene G73A polymorphism functionally affects cystatin C plasma levels.
Noto
Davide
D
Department of Internal Medicine and Geriatrics, University of Palermo, Via del Vespro 141, Palermo I-90127, Italy.
Cefalu'
Angelo Baldassare
AB
Barbagallo
Carlo Maria
CM
Pace
Antonio
A
Rizzo
Manfredi
M
Marino
Giuseppina
G
Caldarella
Rosalia
R
Castello
Antonio
A
Pernice
Vincenzo
V
Notarbartolo
Alberto
A
Averna
Maurizio Rocco
MR
D000368:Aged; D000789:Angina, Unstable / Q000097:blood* / Q000235:genetics*; D016022:Case-Control Studies; D002784:Cholesterol / Q000097:blood; D055316:Cystatin C; D015891:Cystatins / Q000097:blood* / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics; D013997:Time Factors; D014280:Triglycerides / Q000097:blood
C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D014280:Triglycerides; D002784:Cholesterol