Zerrin Bicik1, Sevim Gönen2, Talat Bahçebasi3, Kadriye Reis2, Turgay Arinsoy2, Sükrü Sindel2. 1. Department of Nephrology, Medical Faculty, Abant lzzet Baysal University, Düzce, Turkey. 2. Department of Nephrology, Medical Faculty, Gazi University, Ankara,Turkey. 3. Department of Public Health and Biostatistics, Medical Faculty, AbantIzzet Baysal University, Düzce, Turkey.
Abstract
BACKGROUND: Many studies have shown that transforming growth factor(TGF)-β has a major role in renal scarring in many renal diseases and hypertension. OBJECTIVES: The primary aim of this study was to investigate both the relationship between hypertension and serum and urinary levels of TGF-β2 (a more sensitive isoform for glomeruli than TGF-β1), and the effects of combination therapy with perindopril + indapamide on microalbuminuria, which becomes an early indicator of hypertensive benign nephropathy, and serum and urinary TGF-β2 levels in patients with mild to moderate essential hypertension. In addition, we examined the possible relationship between TGF-β2 gene polymorphism and essential hypertension. METHODS: This study was conducted at the Department of Nephrology, Medical Faculty, Gazi University, Ankara, Turkey. Patients aged ≥18 years with newly diagnosed mild to moderate essential hypertension (systolic/diastolic blood pressure [SBP/DBP] >120/>80 mm Hg) who had not previously received antihypertensive treatment were included in the study. Patients with stage I hypertension received perindopril 2 mg + indapamide 0.625 mg (tablet), and patients with stage lI hypertension received perindopril 4 mg + indapamide 1.125 mg (tablet). All study drugs were given OD (morning) PO with food for 6 months. Serum and urinary TGF-β2 and creatinine levels and serum and urinary albumin levels were measured before and after perindopril + indapamide administration. Amplified DNA fragments of the TGF-β2 primer region were screened using amplification refractory mutation system polymerase chain reaction analysis, and the number of ACA repeats was confirmed by DNA sequencing. Genetic studies were performed using a commercial TGF-β2 kit. RESULTS: Forty patients were enrolled in the study, and 38 patients (27 women, 11 men; mean [SD] age, 46.3 [6.5] years) completed it. SBP and DBP were significantly decreased from baseline with perindopril/indapamide (both, P < 0.001). Microalbuminuria and urinary TGF-β2 levels also decreased significantly from baseline (P = 0.04 and P < 0.001, respectively), whereas the serum TGF-β2 level did not change significantly. Three patients, all of whom were found to have TGF-β2 gene mutations, had increased urinary TGF-β2 levels despite good blood pressure control. CONCLUSIONS: The results of this study in patients with mild to moderate hypertension suggest that, despite good clinical control of blood pressure, the persistence of microalbuminuria and high urinary TGF-β2 levels might predict renal impairment. When treating these patients, genetic tendencies and possible polymorphisms on the TGF-β2 locus should be kept in mind.
BACKGROUND: Many studies have shown that transforming growth factor(TGF)-β has a major role in renal scarring in many renal diseases and hypertension. OBJECTIVES: The primary aim of this study was to investigate both the relationship between hypertension and serum and urinary levels of TGF-β2 (a more sensitive isoform for glomeruli than TGF-β1), and the effects of combination therapy with perindopril + indapamide on microalbuminuria, which becomes an early indicator of hypertensive benign nephropathy, and serum and urinary TGF-β2 levels in patients with mild to moderate essential hypertension. In addition, we examined the possible relationship between TGF-β2 gene polymorphism and essential hypertension. METHODS: This study was conducted at the Department of Nephrology, Medical Faculty, Gazi University, Ankara, Turkey. Patients aged ≥18 years with newly diagnosed mild to moderate essential hypertension (systolic/diastolic blood pressure [SBP/DBP] >120/>80 mm Hg) who had not previously received antihypertensive treatment were included in the study. Patients with stage I hypertension received perindopril 2 mg + indapamide 0.625 mg (tablet), and patients with stage lI hypertension received perindopril 4 mg + indapamide 1.125 mg (tablet). All study drugs were given OD (morning) PO with food for 6 months. Serum and urinary TGF-β2 and creatinine levels and serum and urinary albumin levels were measured before and after perindopril + indapamide administration. Amplified DNA fragments of the TGF-β2 primer region were screened using amplification refractory mutation system polymerase chain reaction analysis, and the number of ACA repeats was confirmed by DNA sequencing. Genetic studies were performed using a commercial TGF-β2 kit. RESULTS: Forty patients were enrolled in the study, and 38 patients (27 women, 11 men; mean [SD] age, 46.3 [6.5] years) completed it. SBP and DBP were significantly decreased from baseline with perindopril/indapamide (both, P < 0.001). Microalbuminuria and urinary TGF-β2 levels also decreased significantly from baseline (P = 0.04 and P < 0.001, respectively), whereas the serum TGF-β2 level did not change significantly. Three patients, all of whom were found to have TGF-β2 gene mutations, had increased urinary TGF-β2 levels despite good blood pressure control. CONCLUSIONS: The results of this study in patients with mild to moderate hypertension suggest that, despite good clinical control of blood pressure, the persistence of microalbuminuria and high urinary TGF-β2 levels might predict renal impairment. When treating these patients, genetic tendencies and possible polymorphisms on the TGF-β2 locus should be kept in mind.