Issue 4, 2011 November 2011 Welcome to the last issue of Kidney and Blood Pressure Research Digest (KBPR Digest) in 2011. We would like to draw your attention to articles of outstanding importance in the field of nephrology and hypertension. We therefore present short summaries of these articles 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 articles which are presented below. Professor Thomas Quaschning, MD, PHD In behalf of the Editorial Board of Kidney and Blood Pressure Research mail@thomas-quaschning.de  Digest of issue 6/2011 Issue 6/2011 of Kidney and Blood Pressure Research covers a wide spectrum of clinical and preclinical topics. It contains a study which investigates the role of oxidative stress and endothelin-1 in atherosclerotic renal artery stenosis as well as an evaluation of markers for chronic inflammation in patients with impaired renal function. Furthermore, the issue contains a study which highlights the impact of sodium mass balance in haemodialysis patients. Renal artery stenosis (RAS) is relatively common in patients with generalized atherosclerosis and may lead to aggravated hypertension, decreased glomerular filtration rate and eventually to end-stage renal disease. The aim of the present study by Saeed and colleagues (Kidney Blood Press Res 2011;34:396-403) was to examine biomarkers of oxidative stress (oxs) and endothelin (ET)-1 in hypertensive patients with atherosclerotic renal artery stenosis (ARAS) and to evaluate the effect of percutaneous transluminal renal angioplasty (PTRA). Therefore, baseline measurements were made immediately before renal angiography in patients with suspected ARAS (significant ARAS, n = 83, and non-RAS, n = 59) and in 20 healthy, matched controls. In patients with ARAS, analyses were repeated 4 weeks after PTRA. All patients were treated with statins and acetylsalicylic acid throughout. The authors reported that at baseline there were no significant differences between groups in biomarkers of oxs, whereas high-sensitivity C-reactive protein and blood leukocytes were significantly elevated in group ARAS versus both healthy controls and group non-RAS. Plasma levels of ET-1 and uric acid were significantly increased in group ARAS versus healthy controls prior to angiography and were significantly reduced compared to baseline 4 weeks after PTRA. PTRA had no significant effects on biomarkers of oxs, inflammation or serum creatinine concentrations. In conclusion, in the present study patients with ARAS showed no increase in oxs, although inflammatory indices were significantly elevated. These results indicate that despite treatment with antihypertensive agents, acetylsalicylic acid and statins, inflammation is still elevated in ARAS patients and appears to be independent of oxs. In addition, PTRA had a differentiated effect on biomarkers and reduced plasma levels of ET-1 but did not affect high-sensitivity C-reactive protein. The clinical implications of these interesting findings need to be examined further. The calcium-binding protein S100A12 (EN-RAGE) causes inflammation through interaction with the multiligand receptor for advanced glycation end products (RAGE). The aim of the present study by a Czech group of scientists (Kidney Blood Press Res 2011;34:457-464) was to determine S100A12 levels and describe their relationship to inflammatory markers in patients with decreased renal function. The authors studied a group of 46 patients with various degrees of chronic renal insufficiency (CHRI), 31 long-term haemodialysis (HD) patients and 24 healthy controls. In these patients, S100A12 and soluble RAGE were assessed immunochemically, and routine biochemical parameters were measured. S100A12 levels were not different in CHRI and HD patients as compared to controls. In CHRI patients, S100A12 correlated with C-reactive protein (CRP) levels, orosomucoid, and inversely with alpha2-macroglobulin. In HD patients, S100A12 correlated with age, CRP, orosomucoid, fibrinogen and leukocyte levels. In multivariate regression analysis after adjustment for age, S100A12 levels remained correlated with orosomucoid in CHRI patients, CRP, leukocytes, fibrinogen and negatively correlated with sRAGE in HD patients and leukocytes in controls. The authors conclude that EN-RAGE, as representing a sensitive and specific marker of localized inflammatory process, is not elevated in patients with decreased renal function at stable clinical status without signs of overt inflammation. Even in these basal conditions, it is significantly related to inflammatory markers. In addition, this study shows that S100A12 is present in the urine, and urine levels are higher in comparison with those in serum, and correlate with renal function. This finding warrants further investigation to understand the importance of S100A12 in the inflammatory process, and to determine its utility as an inflammatory biomarker in patients with kidney disease. Failure to achieve isonatric haemodialysis drives an expansion of extracellular volume leading to increased interdialytic weight gain. This may be a causative factor in the development of haemodialysis. In their present study, Odudu and coworkers (Kidney Blood Press Res 2011;34:439-446) examined total and diffusive sodium mass balance during haemodialysis. Therefore, 24 chronic haemodialysis patients using a fixed 140 mmol/l sodium concentration were studied over 4 weeks. Dialysate and plasma conductivity and ionic mass balance (IMB) were recorded. IMB estimates total ionic transfer across the HD membrane. The authors showed that mean total IMB was 338 mmol per dialysis indicating net sodium removal. Intrapatient variability was less than interpatient variability. The diffusive component of ionic mass balance was 97 mmol approximating 29% of total sodium removal. The diffusive component also correlated with plasma conductivity, predialysis plasma sodium and with both the reduction in plasma conductivity and plasma sodium during haemodialysis. The authors conclude that the use of online conductivity monitoring to study sodium mass balance appears to be both feasible and useful in individual patients. This study supports the notion that using a fixed rather than individualised dialysate sodium prescription leads to a wide range of sodium removal with potentially unrecognised sodium loading in patients, particularly those who are hyponatraemic. Online conductivity monitoring can be utilised as part of a variety of proposed strategies to enable the delivery of individualised and isonatric haemodialysis. Further study is required to explore the utility of such strategies, which may be crucial in reducing interdialytic weight gain and haemodialysis-induced cardiac injury. For submission of articles or sign-ups to ToC Alerts, please go to the journal's homepage © S. Karger AG - Medical and Scientific Publishers Allschwilerstrasse 10, P.O. 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