A novel serum protein of molecular weight 182 kDa: a molecular marker for an early detection of increased left ventricular mass in patients with cardiac hypertrophy.

Background: Earlier studies in our laboratory have shown the presence of a cardiac-hypertrophy-specific high-molecular-weight protein of 182 kDa in the sera of laboratory rats which were subjected to aortic stenosis. On the basis of a number of criteria, these studies have pointed out that this protein may be a molecular signal of hypertrophic growth in the aorta-constricted animals. Further, a similar high-molecular-weight protein has been observed in the sera of normal humans and patients with cardiac anomalies. We have tried to correlate the levels of 182 kDa serum protein with various parameters such as age, severity of hypertrophy and left ventricular muscle (LVM) mass in patients with cardiac hypertrophy.

Methods: Two hundred and ten patients with left and right ventricular hypertrophy evidenced by clinical history, physical examination, electrocardiogram and echocardiogram were selected for the study. Sandwich enzyme-linked immunosorbent assay (ELISA) technique was used to quantify the 182 kDa serum protein in the sera of patients by using anti-rat 182 kDa protein antibodies.

Results: The 182 kDa protein levels in the serum correlated with the age and stage of the LVM mass of hypertrophied heart in patients. It was noted that this protein was significantly elevated in early and moderate stages of cardiac hypertrophy and decreased when the hypertrophy became severe in patients only up to 40 years of age, whereas no significant difference exists in 182 kDa protein levels between normal individuals and patients with cardiac hypertrophy aged over 40 years.

Conclusion: The level of this protein could be an early molecular marker identifying the stages of increase in LVM mass in patients with cardiac hypertrophy, below 40 years of age. The induction of 182 kDa protein levels in human serum may be an age-dependent phenomenon.