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Background/Aims: Angiotensin II (AngII) is pivotal in the pathogenesis of progressive kidney disease. We have recently shown that AngII induced an increase in markers of oxidative stress, adaptive responses and upregulated stress-related gene expression in immortalised human proximal tubular (HK-2) cells. However, these observed effects of AngII were not mediated solely via AngII type 1 receptor (ATR1). Both HK-2 cells and primary human renal proximal tubular cells (RPTEC) are useful tools to investigate the renin-angiotensin system (RAS), but data on the local expression of the RAS in these cells remain limited. We therefore characterised RAS expression in RPTEC and HK-2 cells. Methods: The mRNA and protein expression of RAS in RPTEC and HK-2 cells was examined by RT-PCR, Western blotting and immunoprecipitation. Results: In both cell lines, mRNA for angiotensin-converting enzyme (ACE) and mRNA and protein expression for angiotensinogen, renin, ACE2, ATR1 and ATR4 were detected. Candesartan, a specific ATR1 blocker, effectively blocked the expression of 80% of the stress-related genes that were upregulated in HK-2 cells following exposure to AngII. Con clusion: These data support a role for AngII in mediating oxidative stress via other receptor types stimulated by AngII and confirm that it is possible to investigate ATR4 pathways of potential injury in RPTEC. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background/Aims: The high morbidity and mortality rates in hemodialysis (HD) patients are due, at least in part, to their increased risk for cardiovascular diseases (CVD). This prospective study evaluated the effect of growth hormone (GH) on a number of CVD risk markers in adult patients on HD. Methods: 139 HD patients were randomized to one of three GH doses or to placebo. Change from baseline in lean body mass (LBM), CVD risk markers (e.g. lipid profile, plasma homocysteine, inflammatory markers, blood pressure, IGF-I, IGFBP-3 and echocardiography) and correlations with serum IGF-I levels and body mass index were evaluated. Results: LBM increased in GH-treated groups compared with placebo (p < 0.001 pooled GH groups vs. placebo). IGF-I (p = 0.0027) and serum high-density-lipoprotein cholesterol levels (p = 0.038) increased with GH treatment. Serum low-density-lipoprotein cholesterol showed a trend to reduction. IGF-I was negatively correlated with plasma homocysteine levels (p = 0.01) and systolic blood pressure (p < 0.0001). Logistic regression analysis showed that interleukin-6, ghrelin and hematocrit values were significant determinants of all-cause mortality. Left ventricular mass was unchanged from baseline in GH-treated groups. Conclusion: In adult HD patients, GH treatment had a predominantly beneficial effect on CVD risk markers. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Chronic metabolic acidosis occurs commonly in chronic renal failure (CRF). The proximal renal tubular cell is the site in the kidney of high oxidative metabolic activity and in CRF is associated with adaptive hypertrophy and hypermetabolism. We hypothesised that chronic acidosis may lead to increased generation of reactive oxygen species due to increased oxidative activity. We developed a novel model of chronic acidosis in LLC-PK1 cells and measured markers of oxidative stress and metabolism. Acidosis led to a reduction in cellular total glutathione and protein thiol content and an increase in glutathione peroxidase activity and NH[sub 3] generation. The expression of constitutively expressed heat stress protein (HSP) HSC70 and HSP60 increased at pH 7.0.Copyright © 2003 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]