Review Articles

Until recently gadolinium chelates were thought to be safe when used as contrast agents for MRI. These compounds are now known to be associated with artifactual results of laboratory tests, acute kidney injury and nephrogenic systemic fibrosis, complications that seem to exclusively affect people with impaired renal function. Penfield and Reilly provide the information that physicians need to determine the relative risks and benefits of administering gadolinium to patients with chronic kidney disease.

The difficulties that are inherent in the differential diagnosis of hemolytic uremic syndrome and thrombotic thrombocytopenic purpura are a function of the overlap in presenting features. The authors of this Review assert that patient management could be more usefully directed by basing diagnosis on recently elucidated pathogenic mechanisms. To that end, they discuss the involvement of deficiencies in metalloprotease ADAMTS13, and dysfunctional complement proteins.

Members of the WNK family of novel serine/threonine kinases inhibit secretion of potassium from the kidney via ROMK. Potassium deficiency—a common problem of modern diets—promotes potassium retention by upregulating WNK1. In this Review of data from animal and human studies, Huang and Kuo frame the hypothesis that WNK-mediated potassium retention is accompanied by sodium retention, and thereby contributes to the development of salt-sensitive hypertension.

It is important that care providers recognize that increased blood pressure during gestation increases a woman's chances of developing cardiovascular problems later in life. To that end, authors from the Mayo Clinic have brought together data that support this association. As we lack large-scale studies of prevention strategies, Garovic and Hayman recommend that women who have had hypertensive pregnancies should be carefully monitored after pregnancy for risk factors associated with cardiovascular disease.

The bio-incompatible characteristics of standard peritoneal dialysis solutions, such as high glucose concentration and nonphysiologic pH, have spurred the development of a new generation of more-biocompatible solutions. In this overview of available clinical data, the advantages and drawbacks of using fluids that contain amino acids or icodextrin, or that have a neutral pH, are debated. The authors conclude that the new peritoneal dialysis solutions hold great promise for improving ultrafiltration and clinical outcomes.

There is currently insufficient evidence to recommend screening of kidney allograft donors and recipients for parvovirus B19 infection. As such, physicians managing recipients need to have a high index of suspicion, and include this type of infection in their differential diagnosis of chronic anemia and other cytopenias in the post-transplantation period. Here, Waldman and Kopp from the NIH review the pathogenesis, diagnosis and management of parvovirus B19 infection.

This wide-ranging introduction to new technologies for the management of renal failure touches on the optimization of conventional dialysis and on alternative techniques such as transplantation methods, artificial kidneys, tissue engineering strategies and harnessing the regenerative capacity of stem cells. The potential for other organs to 'host' renal functions, and the co-opting of developmental plasticity, are also discussed.

Vesicoureteral reflux is a prevalent disease commonly encountered by primary pediatricians, pediatric nephrologists and pediatric urologists. Few issues in pediatrics generate as much controversy as the management of this condition. Different treatment options, as well as pathophysiology, clinical presentation and initial work-up, and radiographic assessment, are discussed here by two urological and surgical specialists.

Bomback and Klemmer have systematically reviewed the literature on aldosterone breakthrough in people treated with angiotensin-converting-enzyme inhibitors and angiotensin-receptor blockers. Although the data are not yet supportive of widespread screening of asymptomatic patients, the authors contend that physicians should test for this phenomenon in selected patients and consider initiating treatment with aldosterone antagonists or renin inhibitors.

Studies of kidney function after orthotopic liver transplantation have yielded conflicting results, and there is a paucity of data on renal outcomes after combined liver–kidney transplantation. In this Review, authors from the University of California, Los Angeles attempt to synthesize the available findings into a cohesive update. Focus is given to the effect of the introduction of the MELD scoring system.

Although cardiovascular disease is the most common cause of death among people with chronic renal dysfunction, conventional cardiovascular risk factors are paradoxically associated with improved survival in hemodialysis populations. Here, the authors analyze emerging data that support this 'reverse epidemiology'. Confirmation of this phenomenon might lead to the formulation of more effective management strategies, tailored to patient characteristics and disease stage.

The authors provide a brief overview of the physiological and pharmacological relevance of proteins that translocate organic anions. Focusing on OATs located in the basolateral membrane of proximal tubule cells, the authors discuss data fromXenopusoocytes and knockout mice. The potential for new findings to shed light on an individual patient's response to treatment with a particular drug, and the risks of toxic effects, are emphasized.

Elucidating the mechanisms that contribute to disease development often requires experiments that are difficult to perform in patients. Mutant mice that recapitulate the characteristics of the X-linked disorder Dent disease have proved to be useful experimental surrogates. Here, an investigator involved in development of one of these mouse models summarizes the most clinically relevant data that have been generated to date.

The Acute Kidney Injury Network (AKIN) met in Amsterdam, The Netherlands, in September 2005. At the 2-day meeting, participants in this multidisciplinary collaboration proposed a standard definition, and scheme for the classification, of AKI. Widespread adoption of these standards, presented here by members of the AKIN working group, would help to advance the study of this condition, and improve patient outcomes.

The Appropriate Blood Pressure Control in Diabetes (ABCD) study remains one of the most relevant sources of data on the vexed issue of optimum management of blood pressure in diabetic patients. This Review by trial investigators provides a more-comprehensive description of data that have emerged from this 5-year, randomized study of moderate versus intensive control of blood pressure using either a calcium channel blocker or an ACE inhibitor.

The authors analyze experimental findings which indicate that limiting protein intake protects the kidney and ameliorates uremic symptoms, outline how the body adapts to reduced protein intake, and describe the metabolic benefits for people with chronic kidney disease. Data from randomized controlled trials and meta-analyses pertaining to the effects of low-protein diets in this population are reviewed.

Hospitalized patients have several stimuli for vasopressin production that increase the risk of their serum sodium concentration dropping to dangerous levels. Here, Moritz and Ayus elegantly present evidence to support their opinion that prevention and management of hyponatremia are worryingly inadequate in many institutions. They assert that fundamental changes to long-standing, but erroneous, tenets of fluid therapy are needed to prevent unnecessary deaths.

A group from Technion, Israel, presents data to support an association between diabetic complications and the pattern of inheritance of alleles for the hemoglobin-binding protein haptoglobin. Experimental and preliminary clinical evidence indicate that the antioxidant protection conferred by haptoglobin is dependent upon genotype. Confirmation of the hypothesis will provide the rationale for trials of genotype-guided antioxidant therapies in diabetic populations.

Unfortunately, dialysis and kidney transplantation do not always ameliorate the retarded growth that is a feature of pediatric end-stage renal disease. This discussion encompasses the main factors that affect the growth of children after transplantation, including age at transplantation, function of the grafted kidney and use of corticosteroids. Evidence for and against the use of recombinant human growth hormone in this patient population is presented.

The authors present the latest evidence supporting genetic contributions to IgA nephropathy, a common form of primary glomerulonephritis throughout the world. No specific causative gene has yet been detected, but defective glycosylation of IgA1 leading to formation of immune complexes has been consistently implicated. The prevalence of familial forms of the condition varies depending on geography and ethnicity. The clinical patterns of these under-recognized familial forms are reviewed here.