Research article

Relationship between apolipoprotein(a) size polymorphism and coronary heart disease in overweight subjects

Enzo Emanuele^{* 1} , Emmanouil Peros^{* 1,2} , Piercarlo Minoretti^1,2 , Colomba Falcone³ , Angela D'Angelo¹ , Lorenza Montagna¹ and Diego Geroldi^1,2

¹Molecular Medicine Laboratory, IRCCS San Matteo Hospital, University of Pavia, Italy

²Department of Internal Medicine and Medical Therapeutics, IRCCS San Matteo Hospital, University of Pavia, Italy

³Division of Cardiology, IRCCS San Matteo Hospital, University of Pavia, Italy

author email corresponding author email* Contributed equally

BMC Cardiovascular Disorders 2003, 3:12doi:10.1186/1471-2261-3-12

Published:	12 December 2003

Abstract

Background

Overweight is associated with an increased cardiovascular risk which is only partially explained by conventional risk factors. The objective of this study was to evaluate lipoprotein(a) [Lp(a)] plasma levels and apolipoprotein(a) [apo(a)] phenotypes in relation to coronary heart disease (CHD) in overweight subjects.

Methods

A total of 275 overweight (BMI ≥ 27 kg/m²) subjects, of which 155 had experienced a CHD event, 337 normal weight subjects with prior CHD and 103 CHD-free normal weight subjects were enrolled in the study. Lp(a) levels were determined by an ELISA technique and apo(a) isoforms were detected by a high-resolution immunoblotting method.

Results

Lp(a) levels were similar in the three study groups. Overweight subjects with CHD had Lp(a) concentrations significantly higher than those without [median (interquartile range): 20 (5–50.3) versus 12.6 (2.6–38.6) mg/dl, P < 0.05]. Furthermore, overweight subjects with CHD showed a higher prevalence of low molecular weight apo(a) isoforms than those without (55.5% versus 40.8%, P < 0.05) and with respect to the control group (55.5% versus 39.8%, P < 0.05). Stepwise regression analysis showed that apo(a) phenotypes, but not Lp(a) levels, entered the model as significant independent predictors of CHD in overweight subjects.

Conclusions

Our data indicate that small-sized apo(a) isoforms are associated with CHD in overweight subjects. The characterization of apo(a) phenotypes might serve as a reliable biomarker to better assess the overall CHD risk of each subject with elevated BMI, leading to more intensive treatment of modifiable cardiovascular risk factors.