Usefulness of serum carboxy-terminal propeptide of procollagen type I in assessment of the cardioreparative ability of antihypertensive treatment in hypertensive patients

Background - We investigated whether serum concentration of carboxy-termina l propeptide of procollagen type I (PIP), a marker of collagen type I synth esis, can be used to assess the ability of antihypertensive treatment to re gress myocardial fibrosis in hypertensive patients. Methods and Results - The study was performed in 37 patients with essential hypertension and hypertensive heart disease. After randomization, 21 patie nts were assigned to losartan and 16 patients to amlodipine treatment. At b aseline and after 12 months, right septal endomyocardial biopsies were perf ormed to quantify collagen volume fraction (CVF) on picrosirius red-stained sections with an automated image-analysis system. Serum PIP was measured b y specific radioimmunoassay. Nineteen patients in the losartan group and 11 in the amlodipine group finished the study. Time-course changes in brood p ressure during treatment were similar in the 2 groups of patients. In losar tan-treated patients, CVF decreased from 5.65 +/-2.03% to 3.96 +/-1.46% (P <0.01) and PIP from 127 +/- 30 to 99 +/- 26 mug/L (P <0.01), Neither CVF or PIP changed significantly in amlodipine-treated patients. CVF was directly correlated with PIP (r=0.44, P <0.001) in all hypertensives before and aft er treatment. Conclusions These findings suggest that the ability of antihypertensive tre atment to regress fibrosis in hypertensives with biopsy-proven myocardial f ibrosis is independent of its antihypertensive efficacy. Our data also sugg est that blockade of the angiotensin II type 1 receptor is associated with inhibition of collagen type I synthesis and regression of myocardial fibros is in hypertensives. Thus, determination of serum PIP may be useful to asse ss the cardioreparative properties of antihypertensive treatment in hyperte nsives.