Issue 4, 2009November, 2009 Welcome to the fourth issue of Kidney and Blood Pressure Research Digest (KBPR Digest). We would again like to draw your attention to articles of outstanding importance in the field of nephrology and hypertension by presenting short summaries to the scientific community in the form of KBPR Digest. KBPR Digest provides readers from all over the world with a free and concise overview on interesting topics which are part of the current issue of Kidney and Blood Pressure Research. We hope that you will be inspired to get to know more about the details of the articles which are discussed below. Professor Thomas Quaschning, MD, PHD On behalf of the Editorial Board of Kidney and Blood Pressure Research mail@thomas-quaschning.de   Digest of issue 5/2009 Issue 5/2009 of Kidney and Blood Pressure Research covers a wide spectrum of clinical and preclinical topics. It contains a study which explores the protective effects of adiponectin in hemodialysis patients as well as an evaluation of the relation of serum heat shock proteins and dialysis modalities. A third study examines the effects of salt load in combination with exogenous angiotensin II on the intrarenal angiotensin regulation in an animal model. Adiponectin, a 29-kDa protein, is the most abundant adipose tissue-derived protein in human plasma. Adiponectin has insulin-sensitizing, anti-inflammatory and anti-atherosclerotic properties; however, adiponectin plays a controversial role in chronic renal diseases. The adiponectin level is increased in kidney failure and decreased shortly after kidney transplantation, suggesting that the kidneys play an important role in adiponectin biodegradation and/or elimination. In their study, Peti and coworkers (Kidney Blood Press Res 2009;32:360-365) for the first time investigated the possible relationship between adiponectin with paraoxonase 1 activity (PON1) and sE-selectin in kidney failure. Predialysis serum adiponectin, PON1 and sE-selectin, as well as other metabolic variables, were measured in 70 HD patients. The authors found that adiponectin had no association with PON1 or sE-selectin, a positive association with dialysis efficiency and HDL-C, and an inverse association with BMI, waist circumference, HOMA IR, serum triglycerides, hsCRP, fibrinogen, and albumin. Moreover, albumin, BMI, and HOMA-IR were demonstrated to be independent negative predictors of adiponectin. The findings of the Hungarian scientists raise the possibility that the uremic environment, despite the kidney failure-related hyperadiponectinemia, may overwhelm the protective effect of adiponectin against endothelial dysfunction and low PON1 activity. Furthermore, adiponectin is associated with dialysis efficiency and, similar to individuals with preserved kidney function, has traits of metabolic syndrome. These data contribute to the understanding of the role that adiponectin plays in ‘reverse epidemiology’ in chronic renal disease. Dialysis-related complications result, at least partially, from the use of artificial materials or products such as peritoneal fluids or dialysis membranes. These reactions may aggravate oxidative stress and dyslipidemia, thus triggering accelerated atherosclerosis in dialyzed patients. However, a comprehensive explanation for the acceleration of this process remains unknown. It has recently been suggested that heat shock proteins (HSP) may also contribute to the pathogenesis of atherosclerosis and cardiovascular disease. Until now, the elevated concentrations of HSP and antibodies against them have been described in atherosclerotic subjects from the general population, in patients with hypertension and in patients with vascular disease, but there are to date no investigations in dialyzed patients. The aim of the present Polish study by Musial et al. (Kidney Blood Press Res 2009;32:366-372) was to evaluate the serum HSP, their relation to dialysis modality and their possible role as markers of atherosclerosis. Therefore, Hsp60, Hsp90-alpha, anti-Hsp60 and anti-Hsp70 concentrations were assessed by ELISA in 19 children on automated peritoneal dialysis (APD) and in 17 patients on hemodialysis (HD). The authors demonstrated that Hsp60 values were lower and Hsp90-alpha higher in the dialyzed children when compared to the controls, without any difference between the dialysis modalities. Anti-Hsp60 concentrations were increased in all patients and higher in HD patients than in APD patients. The anti-Hsp70 levels in the APD children were decreased versus controls. The authors conclude that the stress response seems to be impaired in all dialyzed children, independent of the modality used. A similarity of Hsp60 and Hsp90-alpha activity in both methods underlines the fact that their concentrations may depend rather on uremia-related factors than on renal replacement therapy. The differences between APD and HD, regarding anti-HSP activity, seem to advocate APD as the method of choice for children because it triggers autoimmune overactivity to a lesser extent than HD. Moreover, the relations between HSP, lipid disturbances and inflammation markers may suggest HSP as possible markers of atherosclerosis in the dialyzed children. Angiotensin II (Ang II) plays a critical role in the regulation of renal hemodynamic and sodium handling through the activation of vascular, glomerular and tubular Ang II type 1 (AT1) receptor-mediated signaling. Besides its classical actions on the cardiovascular system, tissular Ang II has direct paracrine and autocrine effects at the cellular level, influencing cell growth and differentiation, and mediating oxidative stress, inflammation and fibrosis. In earlier studies, Roson and coworkers (Kidney Int 2006;70:1439-1446) showed that, despite suppression of the systemic renin-angiotensin system, acute salt loading in normal rats increased intrarenal Ang II levels and inflammation markers, even before structural and functional changes appeared. The present study was carried out to explore the effect of sodium overload and exogenous Ang II simultaneously infused on local Ang II content in the renal cortex and medulla in normal rats and its relationship with glomerular function, water and electrolyte excretion, and blood arterial pressure changes (Kidney Blood Press Res 2009;32:334-341). The authors demonstrated that Ang II levels in glomeruli and vessels were exacerbated in Sprague-Dawley rats when sodium load and Ang II were given simultaneously, independently of MAP elevation. In tubules, Ang II staining in the presence of sodium overload was even greater when lower concentrations of Ang II were infused. The results of the present study demonstrate an increased sensitivity of local renal Ang II to salt overload and plasma Ang II elevation, which is independent from arterial pressure changes. The data of the Argentinian scientists support the hypothesis that sodium overload is clearly involved in Ang II intrarenal localization and suggest that although Ang II exerts physiological roles, the exacerbated increase of intrarenal Ang II in conditions of progressive sodium retention may be responsible for pathological effects inducing oxidative stress as well as proinflammatory and fibrotic cytokine and chemokine expression. © S. 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