Objective: The serum concentration of procollagen type I carboxyterminal propeptide (PICP) is a good marker for collagen deposition in hypertension. Increased collagen deposition was associated with myocardial fibrosis and increased arterial stiffness. A decreased adiponectin level is associated with increased atherosclerosis. The role of adiponectin and its relation to PICP in essential hypertension have rarely been studied before.
Methods: We recruited 188 non-diabetic uncomplicated hypertensive patients (mean age: 41+/-7 years; 128 men). No patient had vascular complications or renal or liver diseases. Overnight fasting blood samples were collected to assess patient lipid profiles, blood sugar, insulin, high-sensitivity C-reactive protein (hsCRP), PICP and adiponectin. Carotid to radial pulse wave velocity (PWV) measured using tonometry was used as an index of arterial stiffness.
Results: Adiponectin (r = -0.216, p = 0.003) and male gender (p<0.001) were independent determinants of PICP. Diastolic blood pressure (r = 0.422, p<0.001) and current smoking (p = 0.005) were independent determinants of PWV. PWV was significantly correlated with PICP (r = 0.156, p = 0.034). Adiponectin was significantly correlated with triglyceride (r = -0.276, p<0.001), high-density lipoprotein (r = 0.262, p<0.001), the homeostasis model assessment (HOMA) index (r = -0.220, p = 0.002), hsCRP (r = -0.207, p = 0.004) and the body mass index (BMI) (r = -0.202, p = 0.005). After compensation with possible confounding factors, adiponectin was still significantly correlated with PICP (beta = -0.196, p = 0.006).
Conclusion: Serum adiponectin may be a marker for metabolic syndrome in essential hypertension. Adiponectin was significantly negatively correlated with PICP. Metabolic syndrome probably plays an important role in increased collagen synthesis and arterial stiffness through the effects of decreased adiponectin in non-diabetic essential hypertension.