Association of GNB3 C825T polymorphism with plasma electrolyte balance and susceptibility to hypertension

The role of G-protein activation in cardiovascular disorders is well-known. G-protein β3 subunit (GNB3) C825T polymorphism is associated with increased intracellular signal transduction. We investigated the role of the variant in plasma sodium and potassium concentrations and association with hypertension. 345 healthy controls and 455 patients with essential hypertension were enrolled. Plasma renin activity and aldosterone concentration were measured. The variant, typed by SNaPshot, was analyzed on an ABI Prism 3100 Genetic Analyzer and GeneScan. The TT genotype and T allele were over-represented in the patients (p < 0.001, p < 0.0001). Multiple-logistic regression disclosed that the risk of hypertension was significantly greater for TT (p < 0.0001, OR = 6.1, CI = 2.9-12.7). One-way ANOVA revealed that hypertensive T-allele carriers (CT+TT), compared to non-carriers (CC), had a greater body mass index (BMI), mean arterial pressure (MAP) and PAC (p = 0.01, p = 0.01, p < 0.0001, respectively); while the patients with 825TT risk genotype showed higher plasma sodium and lower potassium (p < 0.0001, each). The results strongly emphasize, not only the role of C825T polymorphism by the induction of increased G-protein activity and enhancement of Na/h exchangers, but also the association with higher plasma sodium and lower potassium levels, high BMI and susceptibility to hypertension.

Analysis of Coronary Artery Flow Patterns in Patients with Chest Pain and Normal Coronary Angiogram: Study Using Transthoracic Doppler Echocardiography

BACKGROUND AND OBJECTIVES: The purpose of this study was to analyze the patterns of coronary artery flow, using transthoracic Doppler echocardiography(TE), in subjects with chest pains and normal coronary angiograms. SUBJECTS AND METHODS: 93 patients(M:F=34:59, mean age:57+/-11 years) ith chest pains and normal coronary angiograms were included in this study. After obtaining baseline clinical data, an exercise treadmill test(TT) as performed, according to the Bruce protocol. The peak diastolic coronary artery flow velocity(DV), at rest, and the coronary flow reserve(FR), in the distal left anterior descending coronary artery(AD), were estimated, using dipyridamole, with TTE. After the administration of angiotensin II receptor(AT II) lockers to 12 patients with a CFR or =2.1. In 7(8.3%) of 12 subjects with a CFR <2.1, their CFR increased, with an improvement of the ETT results, following the administration of the AT II blocker, after an average 19+/-9 months. CONCLUSION: The patients with chest pains and normal coronary angiograms have a heterogeneous clinical spectrum, such as hypertensin, slow flow, reduced CFR, and so on. These subjects need treatment according to the etiology and pathogenesis of their condition, which can be followed up by coronary flow measurements, using TTE.

The Role of Renin-Angiotensin System in Progressive Renal Injury / 대한신장학회잡지

Angiotensin II(A II) -a main effector molecule of renin-angiotensin system(RAS) has been known to increase blood pressure and glomerular capillary pressure, and filtration fraction which may be involved in the progressive renal injury process. The action of A II takes place mainly through AT1 receptor. RAS can be blocked by angiotensin converting enzyme inhibitor(ACEI) and recently developed A II AT1 receptor antagonist(AT1 RA). ACEI also activate kinin system, simultaneously. However, AT1 RA does not affect kinin system. The renoprotective mechanism of ACEI may be related with activation of kinin system. In order to evaluate the renoprotective mechanism of long-term ACEI(enalapril, 100mg/L in drinking water for 12 weeks) or AT1 RA treatment(losartan 300mg/L in drinking water for 12 weeks), and its effect on the cytokines and growth factor expressions of renal cortical tissue by compatitive RT-PCR, 46 5/6 nephrectomized(5/6 NPX) rats and 8 sham operated rats were included in this study. Five sixth NPX rats showed marked hypertensin, significant proteinuria and glomerulosclerosis(mean 30.5%) in 12 weeks after surgery. However, enelapril or losartan treated rats revealed significantly lower 24 hour urinary protein excretion(UProtV), systolic blood pressure(SBP), and glomerulosclerosis than those of control 5/6 NPX rats. Plasma renin activity and angiotensin II levels of 5/6 NPX untreated control rats were not significantly increased compared to sham operated rats in 12 week after surgery. Renal cortical renin gene expression of untreated 5/6 NPX rats was significantly suppressed compared to sham operated rats. Enalapril or losartan treated 5/6 NPX rats showed significantly increased renin gene expression compared to untreated 5/6 NPX rats. Renal cortical gene expressions of TGF-beta, TNF-alpha, MCP-1, IL-6, osteopontin, and endothelin-1 were significantly increased in 5/6 NPX untreated control rats compared to sham operated rats. Enalapril or losartan treated 5/6 NPX rats showed significantly less level of renal TGF-beta gene expression compared to 5/6 NPX control rats. The magnitude of SBP and UProtV were significantly positively correlated with the degree of glomeruloslerosis(p<0.001, p<0.001). With the above result, we speculate that because ACEI or AT1 RA showed similar renoprotective effect in 5/6 NPX rats, at least in part, local activation of RAS plays an important role in the progressive renal injury process of this model.

The Role of Renin-Angiotensin System in Progressive Renal Injury / 대한신장학회잡지

Angiotensin II(A II) -a main effector molecule of renin-angiotensin system(RAS) has been known to increase blood pressure and glomerular capillary pressure, and filtration fraction which may be involved in the progressive renal injury process. The action of A II takes place mainly through AT1 receptor. RAS can be blocked by angiotensin converting enzyme inhibitor(ACEI) and recently developed A II AT1 receptor antagonist(AT1 RA). ACEI also activate kinin system, simultaneously. However, AT1 RA does not affect kinin system. The renoprotective mechanism of ACEI may be related with activation of kinin system. In order to evaluate the renoprotective mechanism of long-term ACEI(enalapril, 100mg/L in drinking water for 12 weeks) or AT1 RA treatment(losartan 300mg/L in drinking water for 12 weeks), and its effect on the cytokines and growth factor expressions of renal cortical tissue by compatitive RT-PCR, 46 5/6 nephrectomized(5/6 NPX) rats and 8 sham operated rats were included in this study. Five sixth NPX rats showed marked hypertensin, significant proteinuria and glomerulosclerosis(mean 30.5%) in 12 weeks after surgery. However, enelapril or losartan treated rats revealed significantly lower 24 hour urinary protein excretion(UProtV), systolic blood pressure(SBP), and glomerulosclerosis than those of control 5/6 NPX rats. Plasma renin activity and angiotensin II levels of 5/6 NPX untreated control rats were not significantly increased compared to sham operated rats in 12 week after surgery. Renal cortical renin gene expression of untreated 5/6 NPX rats was significantly suppressed compared to sham operated rats. Enalapril or losartan treated 5/6 NPX rats showed significantly increased renin gene expression compared to untreated 5/6 NPX rats. Renal cortical gene expressions of TGF-beta, TNF-alpha, MCP-1, IL-6, osteopontin, and endothelin-1 were significantly increased in 5/6 NPX untreated control rats compared to sham operated rats. Enalapril or losartan treated 5/6 NPX rats showed significantly less level of renal TGF-beta gene expression compared to 5/6 NPX control rats. The magnitude of SBP and UProtV were significantly positively correlated with the degree of glomeruloslerosis(p<0.001, p<0.001). With the above result, we speculate that because ACEI or AT1 RA showed similar renoprotective effect in 5/6 NPX rats, at least in part, local activation of RAS plays an important role in the progressive renal injury process of this model.