Collagen gene expression and proliferation rate of skin fibroblasts hypertensive subjects

Objective: Despite the claimed disregulation of extracellular matrix synthesis and increased proliferation rate of different cell types in experimental models of hypertension, very few data are available on collagen synthesis and fibroblasts proliferation in essential hypertensive patients (EH). Design and Methods: In cultivated fibroblasts from skin biopsies from 14 EH and 14 healthy normotensive control subjects (NC), collagen I and III and istone H3 mRNA expression, the latter as an index of proliferation rate, was measured by Northern blot analysis. The majority of subjects underwent M-mode, two-dimensional ecocardiography to obtain left ventricular mass (LV) and LV mass index. Results: In EH, istone H3 mRNA expression was significantly increased as compared to NC (M±ES, EH: 2.46±0.66, NC: 0.54±0.2 optical density, p = 0.01). In EH, both collagen I and collagen III mRNA were not statistically different as compared to NC (M±ES, collagen I, EH: 5.6±0.5, NC: 5±0.5 optical density; collagen III, EH: 6.5±0.7, NC: 5±0.6 optical density). Both LV and LV mass index were statistically increased in EH as compared to NC (M±ES, LV, EH: 164±5, NC: 123±4 g, p = 0.00001; LV mass index, EH: 87±3, NC: 73±3 g/m2, p = 0.005). We did not fred any statistically significant correlation between istone, collagen I, collagen III mRNA gene expression and both LV and LV mass index in the studied population. Conclusions: Our data suggest that in human hypertension is present an increased fibroblast proliferation rate that may be due to a genetically-determined defect in cell growth regulation. Data relating to collagen gene expression are not consistent with previous report in human hypertension of an increased collagen synthesis.