Issue 2, 2011 April 2011 Welcome to the 2nd 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, presenting 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 On behalf of the Editorial Board of Kidney and Blood Pressure Research mail@thomas-quaschning.de  Digest of issue 2/2011 Issue 2/2011 of Kidney and Blood Pressure Research covers a wide spectrum of clinical and preclinical topics. It contains a study which investigates the impact of cinacalcet on renal function after kidney transplantation as well as an evaluation of the effects of N-acetylcysteine on renal hemodynamics in an animal model of contrast media-induced nephropathy. Furthermore, the issue contains a study which explores the impact of plasma obestatin levels in hemodialysis patients. Cinacalcet is a calcimimetic drug that increases the sensitivity of the calcium-sensing receptor to extracellular calcium, which leads to a decrease of parathyroid hormone secretion and subsequently to lower serum calcium concentrations. Persistent hyperparathyroidism (HPT) with hypercalcemia after renal transplantation occurs frequently and is a risk factor for bone disease, promotes vascular and tubulointerstitial calcifications and has been associated with decreased graft survival and enhanced post-transplant cardiovascular morbidity and mortality. Cinacalcet effectively reduces calcium in patients with persistent HPT after kidney transplantation. Scientists of the University of Zürich (Kidney Blood Press Res 2011;34:97-103) aimed to assess the association of cinacalcet with a decrease in renal function based on a meta-analysis of observational studies in kidney transplant patients with persistent HPT. They calculated the mean difference between renal function before cinacalcet and at 3 months on cinacalcet treatment for each study. Pooling the studies on kidney transplant patients with persistent HPT (8 studies, n = 115), showed a significant reduction in renal function (p = 0.008). Meta-regression analysis revealed that there was an association between renal function and the amount of calcium reduction under treatment with cinacalcet. A higher delta change in serum calcium levels was associated with a decrease in renal function at 3 months of cinacalcet treatment. The authors concluded that cinacalcet treatment was associated with a decline of renal function in kidney transplant recipients with persistent HPT. Therefore, frequent monitoring of creatinine and calcium levels during cinacalcet treatment is strongly recommended. Contrast media nephropathy is generally defined as an impairment in renal function occurring within 3 days following the intravascular administration of contrast media and the absence of alternative etiology. Patients at increased risk include those with congestive heart failure, renal impairment, and diabetes mellitus, especially in combination. Although the pathogenesis of contrast media nephropathy is incompletely understood, reduced synthesis of prostaglandin and NO, alteration of renal hemodynamics resulting in medullary ischemia, and generation of reactive oxygen species leading to renal tubular toxicity seem to play a role. N-acetylcysteine (NAC) has been proposed to prevent radiocontrast nephropathy in high-risk patients. Krzossok and coworkers (Kidney Blood Press Res 2011;34:125-134) explored the effect of single-dose and prolonged administration of NAC before application of either the ionic, high-osmolar radiocontrast agent diatrizoate sodium (DTZ) or the nonionic, low-osmolar radiocontrast agent iohexol (IOH) in a rat model combining uninephrectomy, salt depletion, and administration of indomethacin. The authors showed that NAC had no effect on renal hemodynamics in control rats. Both DTZ and IOH induced biphasic changes in renal blood flow and cortical renal blood flux and persistently reduced medullary blood flux. Neither single-dose nor prolonged administration of NAC prevented the hemodynamic changes following administration of DTZ or IOH, respectively. Acute prophylactic administration of NAC prevented increased urinary ET excretion after injection of IOH and, to a smaller degree, of DTZ. Both an ionic, high-osmolar (DTZ) and a nonionic, low-osmolar (IOH) radiocontrast agent induce marked changes in renal hemodynamics in salt-depleted rats treated with indomethacin. The authors conclude that renal perfusion is not affected by NAC application in this model of experimental contrast nephropathy in rats. Therefore, other effects of NAC will have to account for the presumed renoprotective properties and will have to be subjected to further evaluation. The hormone obestatin, made up of 23 amino acids with a molecular weight in the region of 2,500 daltons and synthesized in the stomach, is produced through a post-translational cleavage process undertaken by a precursor, preproghrelin. Obestatin has been cited in the complex hormonal network that regulates the energy balance in humans, with an anorectic effect. The main aim of the study by Lacquaniti et al. (Kidney Blood Press Res 2011;34:104-110) was to evaluate obestatin in uremic patients to determine whether it is correlated with nutritional and inflammatory status. The authors studied plasma obestatin in uremic patients (n = 50) undergoing hemodialysis therapy and in healthy subjects. Obestatin levels in uremic patients were significantly lower than in healthy subjects. Patients with a body mass index (BMI) smaller than 23 had lower obestatin levels than those with a BMI greater than 23 (p = 0.001). After multivariate analysis, direct correlations were maintained between obestatin and high-sensitivity C-reactive protein and total alkaline phosphatases, while inverse correlations were found with iron and calcium-phosphorous product. Based on these observational data, obestatin might be implicated in the inflammatory state and the disturbances of calcium/phosphate metabolism of hemodialysis patients. However, further studies are warranted to determine whether this hormone plays a key role in contributing to malnutrition and to the chronic inflammatory process. 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. Box, CH-4009 Basel (Switzerland) Tel. +41 61 306 11 11, Fax +41 61 306 12 34, publications@karger.com. Please read the Karger Privacy Policy. If you have received this email by mistake, click here and we will take you off this mailing list.