SummaryCombined treatment with an angiotensin II receptor blocker and hydrochlorothiazide (HCT) is advocated to control hypertension (HT). Hepatocyte growth factor (HGF) may be a new marker to evaluate endothelial dysfunction (ED), which is a potential target in treating HT. The aim of the present study was to compare the effects of Telmisartan/HCT with Losartan/HCT on serum HGF and ED in hypertensive patients.Hypertensive patients were randomly divided into a Telmisartan/HCT (group T) or Losartan/HCT group (group L) and received one tablet of either drug per day for 8 weeks. Serum HGF, nitric oxide (NO), plasma von Willebrand factor (vWF), and endothelin (ET) were measured before treatment and after 8 weeks of treatment. Twenty healthy subjects were selected as controls (control group).HGF, vWF, ET, and the ET/NO ratio were higher, and NO was lower in hypertensive patients than those in the control group (all P < 0.01). After treatment for 8 weeks, HGF, vWF and ET decreased, and NO increased significantly in both groups (all P < 0.01). The reductions in BP and HGF and increase in NO (∆NO) were not significantly different between the two groups (all P > 0.05), but the reductions in vWF and ET (∆ET) and ∆ET/∆NO ratio were more obvious in group T than in group L (all P < 0.01). There was no significant correlation between the changes in most of the measured parameters and the extent of BP reduction in either group.Both Telmisartan/HCT and Losartan/HCT could decrease serum HGF and improve ED, which was independent of the antihypertensive effects. However, the improvement in ED may be superior with Telmisartan/HCT than Losartan/ HCT when the BP-lowering effects are the same. (Int Heart J 2010; 51: 252-258) Key words: Angiotensin II receptor blocker, Diuretic, Von Willebrand factor, Nitric oxide, Endothelin, Vascular endothelium H ypertension (HT) has become an important threat to human health in recent decades. Data show that the adult prevalence of HT is 18.8%, however, the rates of recognition, treatment, and control of HT were 30.2%, 24.7%, and 6.1%, respectively, in the Chinese population in 2002, all of which are very low levels.1) There were various underlying reasons, among which the nonappropriate selection of antihypertensive drugs was especially important. Numerous studies have indicated that the control rate of blood pressure (BP) was very low when one type of antihypertensive drug was administered alone; nevertheless, an increase in dose would result in significant side effects. Therefore, low-dose combined administration of antihypertensive drugs is advocated, thus enhancing the control rate of BP and decreasing the side effects.2) Among several protocols, combined treatment with an angiotensin II receptor blocker (ARB) and low-dose hydrochlorothiazide (HCT) is commonly used in clinical practice. Vascular endothelium is the largest endocrine and paracrine organ that can secrete many kinds of vasoactive substances to regulate vasodilatation, maintain the balance of the blood clotting and fibrinolysis sys...