Reviews & Analysis

In 2013, four important papers were published that provide new insights on biomarkers in acute kidney injury (AKI). These studies demonstrate the potential for biomarkers to aid clinicians in improving the therapeutic management of patients with AKI and potentially improve patient outcomes.

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.

As current treatment strategies for diabetic nephropathy, namely intensive control of glucose levels and blood pressure, cannot fully prevent the development and progression of the disease, new therapeutic approaches are urgently needed. Here, Muskiet and colleagues discuss the status of currently available incretin-based agents—agonists of glucagon-like peptide 1 and inhibitors of dipeptidyl peptidase 4—and their potential renoprotective effects in patients with type 2 diabetes mellitus.

In 2013, a key theme of research in renal transplantation was the diagnosis of rejection. Data from key studies published in the past year highlight aspects of rejection that warrant further investigation and should prompt the consideration of adjunctive tests to complement traditional histological assessment of allograft biopsy samples.

During 2013, a meta-analysis provided evidence that cystatin C improves estimated glomerular filtration rate in cardiovascular risk categorization in chronic kidney disease (CKD). Another study showed that low diastolic blood pressure (DBP) is harmful in patients with CKD, challenging the paradigm of treating elevated systolic blood pressure regardless of DBP. Overall, mortality rates in CKD have decreased but further improvement is required.

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.

2013 saw the publication of numerous studies that identified resident renal stem or progenitor cells, induced pluripotent stem cells and strategies based on stem cell paracrine action, which all might be suitable for kidney regeneration after injury.

In 2013, substantial progress was made in uncovering the genetic basis of a variety of kidney and urological disorders, including congenital and developmental diseases. The new findings will lead to an increased understanding of the pathophysiology of these diseases, improved risk prediction and the development of novel therapies.

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?

Management of chronic kidney disease in elderly patients is challenging and complex. In this Review, the authors discuss the dilemmas that are associated with the planning and maintenance of a preferred vascular access for haemodialysis in elderly patients, including the ethical issues that might influence therapeutic decision making.

In diabetic nephropathy, excessive activation of the renin–angiotensin–aldosterone system (RAAS) results in progressive renal damage. Here, the authors discuss the efficacy of RAAS blockade for the prevention of disease progression and the mechanisms of renal protection. They also highlight new strategies aimed at optimizing RAAS blockade and improving outcomes in patients with diabetic nephropathy.

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.

Cardiorenal syndrome comprises a heterogeneous group of acute and chronic conditions, which affect patients with combined cardiac and renal dysfunction. Although cardiorenal syndrome is widely recognized, research in this field is hampered by the lack of a universally accepted definition and limited understanding of the hierarchy of factors involved in pathogenesis of the disease. Here, the authors discuss the current understanding of cardiorenal syndrome and suggest a roadmap for future research.

The underlying cause of hypertension is unknown in the vast majority of patients with high blood pressure. This Perspectives article discusses the role of T cells in renal inflammation and how autoimmunity, mediated by heat shock proteins, leads to salt-sensitive hypertension.

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.

Fluid therapy is essential to maintain renal oxygen delivery and glomerular filtration in patients who are at risk of acute kidney injury (AKI). However, patients with AKI are also at risk of fluid overload. This Review discusses the optimal fluid management strategy for patients with AKI, and the need to balance adequate shock resuscitation with the harmful effects of fluid overload.

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.