Correlations between the collagen content of the human left ventricular myocardium, measured by biochemical and morphometric methods

Abstract

Objective - To assess, in myocardium specimens obtained from necropsies, the correlation between the concentration of hydroxypraline, measured with the photocolorimetric method, and the intensity of fibrosis, determined with the morphometric method. Methods - Left ventricle myocardium samples were obtained from 45 patients who had undergone necropsy, some of them with a variety of cardiopathies and others without any heart disease. The concentrations of hydroxyproline were determined with the photocolorimetric method. In the histologic sections from each heart, the myocardial fibrosis was quantified by using a light microscope with an integrating ocular lens. Results - A median of, respectively, 4.5 and 4.3 μg of hydroxyproline/mg of dry weight was found in fixed and nonfixed left ventricle myocardium fragments. A positive correlation occurred between the hydroxyproline concentrations and the intensity of fibrosis, both in the fixed (Sr=+0.25; p-0.099) and in the nonfixed (Sr=+0.32; p=0.03) specimens. Conclusion - The biochemical methodology was proven to be adequate, and manual morphometry was shown to have limitations that may interfere with the statistical significance of correlations for the estimate of fibrosis intensity in the human myocardium.