News & Views in 2013

T-lymphocyte activation antigen CD80 is a B-cell costimulator and podocyte injury marker originally described in lupus nephritis; CD80 blockade with abatacept disappointed in a lupus nephritis trial. A study now suggests abatacept efficacy in focal and segmental glomerulosclerosis. Small patient numbers and concurrent treatment regimens call for more definitive studies regarding this therapeutic strategy.

American and European vascular access guidelines advise intensive surveillance of haemodialysis arteriovenous fistulas (AVFs) with pre-emptive access intervention based on deterioration in access flow. The combination of physical examination, venous pressure and access flow might provide a better indicator of need for intervention and reduce the risk of AVF thrombosis and access loss.

The ACP has published 'weak' guidelines for screening patients for kidney disease based on limited or no data, which could harm patients with undiagnosed or progressive kidney disease. As kidney experts weren't involved in the development of these guidelines, what should all health professionals know about screening for kidney disease?

Parietal epithelial cells (PECs) are increasingly recognized as key players in the pathogenesis of proliferative glomerular diseases. A new study by Rizzo and colleagues contributes to this emerging concept and identifies potential novel signalling pathways that might mediate the activation of PECs. However, the functional role of PECs remains controversial.

A new study presents compelling evidence of an association between moderate to severe psoriasis and chronic kidney disease (CKD). This association seems to be independent of traditional CKD risk factors and indicates that monitoring of kidney function in patients with psoriasis is warranted.

Protein–energy wasting occurs frequently during maintenance dialysis. Known aetiologies include a loss of nutrients during the haemodialysis procedure and anorexia. Providing energy and protein during dialysis improves metabolism; however, the benefits of long-term support are debated. Weiner and colleagues report convincing data with an intradialytic oral nutritional intervention using protein supplements.

Two types of parietal podocyte were previously described in the Bowman capsule: one characterized by coexpression of podocyte and parietal epithelial cell markers, the other characterized by expression of podocyte markers only. New research demonstrates that these populations represent podocyte progenitors and ectopic podocytes—distinct cell types with different clinical implications.

Two recent studies suggest that periprocedural statin administration can prevent contrast-induced acute kidney injury in cardiac patients undergoing percutaneous coronary intervention and in renal patients undergoing angiography, with or without intervention. These studies support the routine administration of potent statins before contrast media infusion in these vulnerable patients.

New data suggest that among kidney transplant recipients, those whose serum contains donor-specific antibodies that bind C1q fare the worst. Although these findings are intriguing, several unanswered questions remain and changing practice to include a C1q binding assay as standard of care in kidney transplantation would be premature.

Albuminuria is rapidly gaining recognition as a marker of the presence and of the progression of chronic kidney disease (CKD). In a new study, Naresh et al. attempt to define cut-off values for percentage change in urinary albumin:creatinine ratio that reflect changes in CKD status rather than random biological variation.

Acidosis affects sodium and potassium excretion, likely via the pH sensitivity of ion transporters. A recent paper shows that β-intercalated cells with deleted H⁺-ATPase release ATP into urine, which induces the production of prostaglandin E2 (PGE2). PGE2 then reduces sodium absorption in the principal cells of the cortical collecting tubule and increases potassium secretion.

In a recent study, Lambie and colleagues suggest that systemic and local intraperitoneal inflammation, evidenced by elevated levels of interleukin-6, are independent processes and have different consequences for patients undergoing peritoneal dialysis. Prevention of inflammation in these patients will, therefore, require different therapeutic approaches.

In contrast to earlier studies that showed a beneficial influence of rituximab on HLA antibody production after kidney transplantation, a recent report by Ashimine et al. questions such an effect. That previous studies included presensitized patients who are more prone to antibody development, might explain this controversy.

The potential roles for autoantibodies in renal transplantation are increasing, as illustrated by a recent report of polyreactive autoantibodies produced by B-cell clones from a kidney transplant recipient that can bind apoptotic cells and activate complement. Such autoantibodies have the potential to amplify microcirculation injury caused by alloantibody in antibody-mediated transplant rejection.

A recent publication by Bonthuis et al. shows a high prevalence of overweight or obesity in children with end-stage renal disease, particularly in renal transplant recipients. Underweight is more prevalent in infants than in other age groups. This study highlights the need to evaluate and implement interventional strategies in this patient population.

Cystatin C continues to show its superiority over serum creatinine in predicting mortality among patients with chronic kidney disease (CKD). This superiority is, in part, due to the non-glomerular filtration rate (GFR) determinants of cystatin C associating with CKD risk factors and outcomes. The definition and classification of CKD should not exclusively equate cystatin C with GFR.

The disease manifestations and outcomes in lupus nephritis are exceptionally heterogeneous. In particular, some ethnic populations are disproportionately affected by the most severe forms of the disease. A new study exploring NF-κB dysregulation and its associated genetic variants might help explain the link between ancestry and outcomes in lupus nephritis.

In a recent study using transgenic mice with inducible podocyte-specific expression of tagged albumin, Tenten and colleagues report transtubular transport of albumin, possibly mediated by the neonatal Fc receptor. This study raises several questions about the physiological importance of this potential pathway and the implications for albuminuria in renal disease.

A recent study developed a formula predicting hard outcomes of rhabdomyolysis (dialysis and death). Based on a rigid analytical approach, an eight factor score was elaborated with acceptable prognostic value, but clinical usefulness at this time seems limited. Perhaps the most promising application is for triage.

Skin carcinomas, triggered by ultraviolet light, commonly develop post-transplantation and are associated with substantial morbidity and mortality. A recent study in kidney transplant recipients has shown that some of these tumours arise from donor-derived cells. This phenomenon is interesting for the study of carcinogenesis, although its effect on clinical practice is unknown.