Tracing angiotensin II's yin-yang effects on cardiovascular-renal pathophysiology.

Adverse changes in cardiovascular and renal systems are major contributors to overall morbidity and mortality. Human cardiovascular and renal systems exhibit a complex network of positive and negative feedback that is reflected in the control of vascular tone via angiotensin II (Ang II) based signaling. This review will examine in some depth, the multiple components and processes that control the status and reflect the health of these various cardiovascular and renal systems, such as pathways associated to monomeric G proteins, RhoA/Rho kinase system and ERK, oxidative stress and NO balance. It will specifically emphasize the "yin-yang" nature of Ang II signaling by comparing and contrasting the effects and activity of various systems, pathways and components found in hypertension to those found in Gitelman's and Bartter's syndromes (GS/BS), two rare autosomal recessive tubulopathies characterized by electrolytic imbalance, metabolic alkalosis, sodium wasting and prominent activation of the renin-angiotensin-aldosterone system. Notwithstanding the activation of the renin-angiotensin-aldosterone system, GS/BS are normo-hypotensive and protected from cardiovascular-renal remodeling and therefore can be considered the mirror image, the opposite of hypertension.

Molecular biology based assessment of green tea effects on oxidative stress and cardiac remodelling in dialysis patients.

BACKGROUND & AIMS: Cardiovascular disease, the most common cause for morbidity and mortality in end-stage renal disease (ESRD), has prompted the exploration of multiple approaches to improve outcomes. Cardiovascular risk factors such as oxidative stress (OxSt) and cardiac remodelling are common in ESRD and dialysis patients. Green tea (GT) is well recognized as reducing OxSt. This 6 months study evaluated in 20 ESRD patients under chronic dialysis, the effect of GT treatment (1 g/day as commercially available capsule) on cellular and plasma OxSt and proliferation related markers using a molecular biology approach. METHODS: Mononuclear cell p22(phox), Haeme Oxygenase (HO)-1 protein expression, and phosphorylated ERK1/2 status were evaluated in dialysis patients at baseline, after 3 and 6 months of GT treatment by Western blot analysis and plasma oxLDL by ELISA. Cardiac remodelling was assessed by echocardiographic left ventricular (LV) mass determination at baseline and at the end of the study. RESULTS: GT treatment reduced p22(phox) and pERK1/2 from baseline while HO-1 increased. At baseline, LV mass correlated with both p22(phox) and oxLDL. GT treatment decreased LV mass from baseline, which correlated with oxLDL. 9 patients had LV hypertrophy at baseline, which, at 6 months, was normalized in 5 and reduced in 3, showing a parallel decrease of p22(phox), pERK1/2, oxLDL and increase of HO-1. CONCLUSIONS: Treatment with GT decreased the expression of OxSt-related proteins tightly associated with cardiovascular disease and decreased LV mass. It appears highly likely that the addition of GT can provide a benefit in terms of cardiovascular protection in dialysis patients.