Transforming growth factor beta in hypertensives with cardiorenal damage

We investigated whether a relationship exists between circulating transform ing growth factor beta -1 (TGF-beta (1)), collagen type I metabolism, micro albuminuria, and left ventricular hypertrophy in essential hypertension and whether the ability of the angiotensin II type 1 receptor antagonist losar tan to correct microalbuminuria and regress left ventricular hypertrophy in hypertensives is related to changes in TGF-beta (1) and collagen type I me tabolism. The study was performed in 30 normotensive healthy controls and 3 0 patients with never-treated essential hypertension classified into 2 grou ps: those with microalbuminuria (urinary albumin excretion > 30 and < 300 m g/24 h) associated with left ventricular hypertrophy (left ventricular mass index > 116 g/m(2) for men and > 104 g/m(2) for women) (group B; n=17) and those without microalbuminuria or left ventricular hypertrophy (group A; n =13). The measurements were repeated in all patients after 6 months of trea tment with losartan (50 mg once daily). The serum concentration of TGF-beta (1) was measured by a 2-site ELISA method, and the serum concentrations of carboxy-terminal propeptide of procollagen type I (a marker of collagen ty pe I synthesis) and carboxy-terminal telopeptide of collagen type I (a mark er of collagen type I degradation) were measured by specific radioimmunoass ays. The duration of hypertension and baseline values of blood pressure wer e similar in the 2 groups of patients. No differences in serum TGF-beta (1) , carboxy-terminal propeptide of procollagen type I, and carboxy-terminal t elopeptide of collagen type I were found between normotensives and group A of hypertensives. Serum TGF-beta (1), carboxy-terninal propeptide of procol lagen type I, and the ratio of carboxy-terminal propeptide of procollagen t ype I to carboxy-terminal telopeptide of collagen type I were increased (P <0.05) in group B of hypertensives compared with group A of hypertensives a nd normotensives. No differences in carboxy-terminal telopeptide of collage n type I were found among the 3 groups of subjects. After treatment with lo sartan, microalbuminuria and left ventricular hypertrophy persisted in 6 pa tients (then considered nonresponders) and disappeared in II patients (then considered responders) from group B. Compared with nonresponders, responde rs exhibited similar control of blood pressure and higher (P <0.05) blockad e of angiotensin II type 1 receptors las assessed by a higher increase in p lasma levels of angiotensin II). Whereas TGF-beta (1), carboxy-terminal pro peptide of procollagen type I, and the ratio of carboxy-terminal propeptide of procollagen type I to carboxy-terminal telopeptide of collagen type I d ecreased (P <0.05) in responders, no changes in these parameters were obser ved in nonresponders. These findings show that an association exists betwee n an excess of TGF-beta (1), stimulation of collagen type I synthesis, inhi bition of collagen type I degradation, and cardiorenal damage in a group of patients with essential hypertension. In addition, our results suggest tha t the ability of losartan to blunt the synthesis of TGF-beta (1) and normal ize collagen type I metabolism may contribute to protect the heart and the kidney in a fraction of patients with essential hypertension.