HIV-associated nephropathy: a review of the epidemiology and clinical course in the HAART era

CKD in HIV-infected patients other than HIV-associated nephropathy

A spectrum of kidney diseases in HIV-infected patients has been reported both before and after the introduction of highly active antiretroviral therapy (HAART). Kidney syndromes affecting HIV-infected patients include CKD as well as proteinuria, nephrotic syndrome, and acute nephritic syndrome. Thrombotic microangiopathy should be considered in patients with kidney disease and typical clinical characteristics. As the HIV-infected population ages, there is increased concern regarding the incidence of vascular and metabolic disease, leading to an increased burden of CKD. Although HIV-associated nephropathy is still the major cause of nephrotic syndrome in HIV-infected patients, immune complex glomerulonephritis (ICGN) still comprises a substantial proportion of the disease burden, especially in people of European origin. Genetic investigations into the underpinnings of the various histologic expressions of HIV-associated kidney disease hold great promise. The single most important diagnostic test to differentiate various forms of kidney disease in HIV-infected patients is a kidney biopsy. The results of treating kidney disease in HIV-infected patients remain unclear, and properly designed randomized controlled trials of the treatment of ICGN with HAART and other approaches are desperately needed.

Pharmacotherapy for human immunodeficiency virus-associated nephropathy

Approximately 10% of adult patients with human immunodeficiency virus (HIV) infection have HIV-associated nephropathy (HIVAN). This condition, a leading cause of renal failure, is characterized by damage to specific areas of the renal filtration system. It manifests with increased serum creatinine levels, overt proteinuria, and in some patients, end-stage renal disease (ESRD). The mortality rate for HIVAN-related ESRD is high-30% within the first year of onset. Most instances of HIVAN occur in patients of African descent. Although advances in defining the pathology have been made, the optimal treatment strategy remains unclear. Potential benefits of potent combination antiretroviral therapy, angiotensin-converting enzyme (ACE) inhibitors, and corticosteroids have been reported in small clinical trials and case reports. Cyclosporine is another option, but clinical experience with this agent in managing HIVAN is limited. Few conclusions can be drawn from the limited body of available evidence. Antiretroviral therapy, ACE inhibitors, and corticosteroids are possibly associated with reversal of serum creatinine level increases and proteinuria, but studies are necessary to further define the role of these agents in therapy. Close monitoring is advised when treating any patient with HIVAN.

HIV-associated renal disorders: recent insights into pathogenesis and treatment

Renal electrolyte disorders, acute renal failure, and a variety of chronic renal diseases are common in HIV-infected patients. Glomerular disorders include IgA nephropathy, cryoglobulinemia, amyloidosis, and a lupus-like immune complex glomerulopathy. The most attention has been focused on collapsing glomerulopathy associated with nephrotic syndrome and progressive renal failure, which appears to be unique for patients with HIV/AIDS, called HIV-associated nephropathy (HIVAN), and it occurs predominantly in African American patients. Investigations in humans and in a transgenic mouse model reveal direct infection of renal epithelial cells by HIV and toxic cellular and immunologic processes mediated by HIV glycoproteins as the principal pathophysiology of HIVAN. Highly active antiretroviral treatment may be associated with an improved renal outcome and even reversal of kidney disease in some patients. Treatment with angiotensin-converting enzyme inhibitors may avert progression of HIVAN to end-stage kidney disease and result in superior patient and kidney survival as compared with untreated patients.

A 20-year history of childhood HIV-associated nephropathy

In 1984, physicians in New York and Miami reported HIV-infected adult patients with heavy proteinuria and rapid progression to end-stage renal disease. These patients showed large edematous kidneys with a combination of focal segmental glomerulosclerosis (FSGS) and tubulointerstitial lesions. This renal syndrome, named HIV-associated nephropathy (HIVAN), was found predominantly in African Americans. Subsequent studies confirmed the presence of HIVAN in children, who frequently develop nephrotic syndrome in association with FSGS and/or mesangial hyperplasia with microcystic tubular dilatation. Since then, substantial progress has been made in our understanding of the etiology and pathogenesis of HIVAN. This article reviews 20 years of research into the pathogenesis of HIVAN and discusses how these concepts could be applied to the treatment of children with HIVAN. HIV-1 infection plays a direct role in the pathogenesis of childhood HIVAN, at least partially by affecting the growth and differentiation of glomerular and tubular epithelial cells and enhancing the renal recruitment of infiltrating mononuclear cells and cytokines. An up-regulation of renal heparan sulfate proteoglycans seems to play a relevant role in this process, by increasing the recruitment of heparin-binding growth factors (i.e., FGF-2), chemokines, HIV-infected cells, and viral proteins (i.e., gp120, Tat). These changes enhance the infectivity of HIV-1 in the kidney and induce injury and proliferation of intrinsic renal cells. Highly active anti-retroviral therapy (HAART) appears to be the most promising treatment to prevent the progression of childhood HIVAN. Hopefully, in the near future, better education, prevention, and treatment programs will lead to the eradication of this fatal childhood disease.