Volume 9 Issue 5, May 2013

Mutations in the genes that encode polycystin-1 and polycystin-2 are the principal cause of autosomal dominant polycystic kidney disease. These proteins form a receptor–ion-channel complex and were thought to regulate tubule luminal diameter in a codependent manner. However, new data suggest a more antagonistic relationship between the proteins.

Proteinuria is a known marker of poor prognosis in kidney transplant recipients. A recent study by Amer et al. brings further insights to this topic by investigating whether the composition of proteinuria affects outcomes.

Hur et al. report that fluid management guided by bioimpedance spectroscopy devices might improve cardiovascular parameters in patients on haemodialysis. However, caution is advisable when using these devices for extracellular volume assessment as overzealous reduction of target weights based on extracellular to intracellular volume ratios could cause premature loss of residual renal function.

Loss of renal function is associated with inflammation and immune system impairment, which results in an increased susceptibility to viral and bacterial infections, poor vaccination responses and an increased risk of malignancies in patients with end-stage renal disease (ESRD). Here, Michiel Betjes describes the effects of uraemia and renal transplantation on cells of the adaptive and innate immune systems. He also outlines the clinical implications of immune system impairment in patients with ESRD and discusses the concept of premature immunological ageing in these patients.

Human kidneys produce more than 4 million litres of virtually protein-free primary urine in a lifetime, clearing more than 250,000 kg of plasma proteins in the process. The sieving process is accomplished by the glomerular filter and understanding this process is a prerequisite to understanding the pathogenesis of proteinuria. Here, the authors summarize the major models that have been proposed for the mechanisms of glomerular filtration and discuss their strengths and limitations, with special emphasis on their proposed model—the electrokinetic model.

Community-acquired acute kidney injury (AKI) has a varied aetiology and is prevalent in developing tropical countries. In this Review, the authors discuss the main causes of community-acquired AKI in tropical countries and the effect of climate and socioeconomic factors on disease prevalence. The authors also discuss future strategies to reduce the burden of AKI in the tropics.

Anaemia is common in patients with chronic kidney disease (CKD) and is associated with increased mortality and morbidity. This Review describes findings from randomized controlled trials and observational studies investigating how target haemoglobin level and erythropoiesis-stimulating agent (ESA) dose affect outcomes in patients with CKD and discusses whether high haemoglobin targets, high ESA dosage or ESA resistance are risk factors for adverse outcomes.

A strong inter-relationship seems to exist between the peritoneal membrane and the kidney in patients on peritoneal dialysis. In this Perspectives article, Nessim and Bargman describe examples of this interplay—such as the mechanisms by which alterations in peritoneal membrane function may influence residual renal function and vice versa—and propose that this interplay be characterized by a new term: 'peritoneal–renal syndrome'.