A urinary biomarker profile for children with HIV-associated renal diseases

The changing landscape of HIV-associated kidney disease

The HIV epidemic has devastated millions of people globally, with approximately 40 million deaths since its start. The availability of antiretroviral therapy (ART) has transformed the prognosis of millions of individuals infected with HIV such that a diagnosis of HIV infection no longer automatically confers death. However, morbidity and mortality remain substantial among people living with HIV. HIV can directly infect the kidney to cause HIV-associated nephropathy (HIVAN) - a disease characterized by podocyte and tubular damage and associated with an increased risk of kidney failure. The reports of HIVAN occurring primarily in those of African ancestry led to the discovery of its association with APOL1 risk alleles. The advent of ART has led to a substantial decrease in the prevalence of HIVAN; however, reports have emerged of an increase in the prevalence of other kidney pathology, such as focal segmental glomerulosclerosis and pathological conditions associated with co-morbidities of ageing, such as hypertension and diabetes mellitus. Early initiation of ART also results in a longer cumulative exposure to medications, increasing the likelihood of nephrotoxicity. A substantial body of literature supports the use of kidney transplantation in people living with HIV, demonstrating significant survival benefits compared with that of people undergoing chronic dialysis, and similar long-term allograft and patient survival compared with that of HIV-negative kidney transplant recipients.

HIV-associated nephropathy in children: challenges in a resource-limited setting

HIV infection remains one of the leading causes of morbidity and mortality worldwide, especially in children living in resource-limited settings. Although the World Health Organization (WHO) recently recommended antiretroviral therapy (ART) initiation upon diagnosis regardless of the number of CD4, ART access remains limited, especially in children living in sub-Saharan Africa (SSA). HIV-infected children who do not receive appropriate ART are at increased risk of developing HIV-associated nephropathy (HIVAN). Although due to genetic susceptibility, SSA is recognized to be the epicenter of HIVAN, limited information is available regarding the burden of HIVAN in children living in Africa. The present review discusses the information available to date on the prevalence, pathogenesis, risk factors, diagnosis, and management of HIVAN in children, focusing on related challenges in a resource-limited setting.

Profiling Biomarkers in HIV Glomerular Disease – Potential for the Non-Invasive Diagnosis of HIVAN?

Background

There is a wide spectrum of kidney pathology in human immunodeficiency virus (HIV) infection, affecting all structures of the kidney. The histology of HIV chronic kidney disease (CKD) is diverse, ranging from HIV-associated nephropathy (HIVAN) to focal glomerulosclerosis (FSGS), HIV-immune complex disease (HIV-ICD), other glomerulopathies and tubulo-interstitial nephritis. Definitive diagnosis is by kidney biopsy, an invasive procedure. However, serum and urinary biomarkers may be useful in predicting the histological diagnosis of HIVAN.

Purpose

We wished to determine the utility of serum and urinary biomarkers in predicting the histological diagnosis of HIVAN.

Patients and Methods

We measured neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, transforming growth factor (TGF)-β isoforms and bone morphogenetic protein (BMP)-7 in the serum and urine in patients with different histological forms of HIV glomerular disease.

Results

In HIVAN, we demonstrated increased levels of serum cystatin C and increased levels of serum and urinary NGAL. Urinary TGF-β1 and TGF-β2 levels were elevated in HIV-positive patients with CKD but were not significantly different in the different HIV histologies, while urinary BMP-7 levels were elevated in minimal change disease.

Conclusion

This study confirmed the presence of increased serum and urinary biomarkers of tubular injury in patients with HIVAN, and increased urinary biomarkers of fibrosis in HIV CKD, and may indicate their value as a non-invasive diagnostic tool for the diagnosis of HIVAN.

Childhood HIV-associated nephropathy: 36 years later

HIV-associated nephropathy (HIVAN) predominantly affects people of African ancestry living with HIV who do not receive appropriate antiretroviral therapy (ART). Childhood HIVAN is characterized by heavy proteinuria and decreased kidney function. Kidney histology shows mesangial expansion, classic or collapsing glomerulosclerosis, and microcystic renal tubular dilatation leading to kidney enlargement. The pathogenesis of HIVAN involves the kidney recruitment of inflammatory cells and the infection of kidney epithelial cells. In addition, both viral and genetic factors play key roles in this disease. Modern ART has improved the outcome and decreased the prevalence of childhood HIVAN. However, physicians have had modest success providing chronic ART to children and adolescents, and we continue to see children with HIVAN all over the world. This article discusses the progress made during the last decade in our understanding of the pathogenesis and treatment of childhood HIVAN, placing particular emphasis on the mechanisms that mediate the infection of kidney epithelial cells, and the roles of cytokines, the HIV-Tat gene, and the Apolipoprotein-1 (APOL1) gene risk variants in this disease. In view of the large number of children living with HIV at risk of developing HIVAN, better prevention and treatment programs are needed to eradicate this disease.

Circulating fibroblast growth factor-2 precipitates HIV nephropathy in mice

People of African ancestry living with the human immunodeficiency virus-1 (HIV-1) are at risk of developing HIV-associated nephropathy (HIVAN). Children with HIVAN frequently show high plasma fibroblast growth factor-2 (FGF-2) levels; however, the role of circulating FGF-2 in the pathogenesis of childhood HIVAN is unclear. Here, we explored how circulating FGF-2 affected the outcome of HIVAN in young HIV-Tg26 mice. Briefly, we demonstrated that FGF-2 was preferentially recruited in the kidneys of mice without pre-existing kidney disease, precipitating HIVAN by activating phosphorylated extracellular signal-regulated kinase (pERK) in renal epithelial cells, without inducing the expression of HIV-1 genes. Wild-type mice injected with recombinant adenoviral FGF-2 (rAd-FGF-2) vectors carrying a secreted form of human FGF-2 developed transient and reversible HIVAN-like lesions, including proteinuria and glomerular enlargement. HIV-Tg26 mice injected with rAd-FGF-2 vectors developed more-significant proliferative and pro-fibrotic inflammatory lesions, similar to those seen in childhood HIVAN. These lesions were partially reversed by treating mice with the FGF/VEGF receptor tyrosine kinase inhibitor PD173074. These findings suggest that high plasma FGF-2 levels may be an independent risk factor for precipitating HIVAN in young children.

Brief Report: Subclinical Kidney Dysfunction in HIV-Infected Children: A Cross-Sectional Study

OBJECTIVE

Most of the kidney dysfunction in HIV-positive children receiving antiretroviral therapy (ART) is attributed to tenofovir. There is a paucity of data on kidney dysfunction in tenofovir-naive children. The primary objective was to know the point prevalence of albuminuria and β2-microglobulinuria in HIV-infected children aged 3-18 years receiving ART. Albuminuria and β2-microglobulinuria were used as surrogates for glomerular and tubular dysfunction, respectively. The secondary objective was to determine their predictors.

DESIGN

Cross-sectional study-design.

METHODS

One hundred consecutive HIV-positive children (3-18 years) on ART were included. Spot urine sample was analyzed for urinary creatinine, total protein, microalbumin, and β2-microglobulin. Albuminuria was defined as albumin to creatinine ratio of >30 mg/g; proteinuria as urine dipstick ≥trace or spot urine protein to creatinine ratio (uPCR) of ≥0.2. β2-microglobulinuria was defined as β2-microglobulin levels of >350 µg/L.

RESULTS

There were 71 boys and 29 girls. Most of the children had WHO clinical stage I and were getting zidovudine-based regimen. Only 7 children were getting tenofovir. estimated Glomerular Filtration Rate and serum creatinine were normal in all children. Approximately half (48%) had renal dysfunction in the form of glomerular dysfunction (26%), tubular dysfunction (27%), or both (5%). Age at diagnosis was significantly associated with β2-microglobulinuria (P = 0.044). None of the selected variables were associated with albuminuria.

CONCLUSIONS

HIV-associated glomerular and tubular dysfunction is common in children receiving ART other than tenofovir. The standard guidelines should consider including routine urinary biomarker monitoring in children on ART.

An HIV-Tat inducible mouse model system of childhood HIV-associated nephropathy

Modern antiretroviral therapies (ART) have decreased the prevalence of HIV-associated nephropathy (HIVAN). Nonetheless, we continue to see children and adolescents with HIVAN all over the world. Furthermore, once HIVAN is established in children, it is difficult to revert its long-term progression, and we need better animal models of childhood HIVAN to test new treatments. To define whether the HIV-1 trans-activator (Tat) gene precipitates HIVAN in young mice, and to develop an inducible mouse model of childhood HIVAN, an HIV-Tat gene cloned from a child with HIVAN was used to generate recombinant adenoviral vectors (rAd-Tat). rAd-Tat and LacZ control vectors (2×109) were expressed in the kidney of newborn wild-type and HIV-transgenic (Tg26) FVB/N mice without significant proteinuria (n=5; 8 per group). Mice were sacrificed 7 and 35 days later to assess their renal outcome, the expression of HIV-genes and growth factors, and markers of cell growth and differentiation by RT-qPCR, immunohistochemistry and/or western blots. HIV-Tat induced the expression of HIV-1 genes and heparin-binding growth factors in the kidney of HIV-Tg26 mice, and precipitated HIVAN in the first month of life. No significant renal changes were detected in wild-type mice infected with rAd-Tat vectors, suggesting that HIV-Tat alone does not induce renal disease. This new mouse model of childhood HIVAN highlights the critical role that HIV-Tat plays in the pathogenesis of HIVAN, and could be used to study the pathogenesis and treatment of HIVAN in children and adolescents.

Plasma and Urinary FGF-2 and VEGF-A Levels Identify Children at Risk for Severe Bleeding after Pediatric Cardiopulmonary Bypass: A Pilot Study

Severe bleeding after cardiothoracic surgery with cardiopulmonary bypass (CPB) is associated with increased morbidity and mortality in adults and children. Fibroblast Growth Factor-2 (FGF-2) and Vascular Endothelial Growth Factor-A (VEGF-A) induce hemorrhage in murine models with heparin exposure. We aim to determine if plasma and urine levels of FGF-2 and VEGF-A in the immediate perioperative period can identify children with severe bleeding after CPB. We performed a prospective, observational biomarker study in 64 children undergoing CPB for congenital heart disease repair from June 2015 - January 2017 in a tertiary pediatric referral center. Primary outcome was severe bleeding defined as ≥ 20% estimated blood volume loss within 24-hours. Independent variables included perioperative plasma and urinary FGF-2 and VEGF-A levels. Analyses included comparative (Wilcoxon rank sum, Fisher's exact, and Student's t tests) and discriminative (receiver operator characteristic [ROC] curve) analyses. Forty-eight (75%) children developed severe bleeding. Median plasma and urinary FGF-2 and VEGF-A levels were elevated in children with severe bleeding compared to without bleeding (preoperative: plasma FGF-2 = 16[10-35] vs. 9[2-13] pg/ml; urine FGF-2= 28[15-76] vs. 14.5[1.5-22] pg/mg; postoperative: plasma VEGF-A = 146[34-379] vs. 53 [0-134] pg/ml; urine VEGF-A = 132 [52-257] vs. 45[0.1-144] pg/mg; all p < 0.05). ROC curve analyses of combined plasma and urinary FGF-2 and VEGF-A levels discriminated severe postoperative bleeding (AUC: 0.73-0.77) with mean sensitivity and specificity above 80%. We conclude that the perioperative plasma and urinary levels of FGF-2 and VEGF-A discriminate risk of severe bleeding after pediatric CPB.

Spectrum of renal disease in HIV-infected children: report of five cases

There is a paucity of literature on renal diseases associated with HIV infection in Asian countries. Renal disease in HIV-infected children can involve the glomerulus, interstitium, tubules or blood vessels of the kidney. In this case series, five HIV-infected children with various forms of renal disease are reported. The renal pathology included HIV-associated nephropathy, collapsing focal segmental glomerulosclerosis without tubular changes, tubule-interstitial nephritis and minimal change disease (MCD). Case five fulfilled the classification criteria for childhood polyarteritis nodosa (PAN). It is important to screen all HIV-infected children for renal disease to enable detection at an early stage.

A review of renal disease in children with HIV infection

Human immunodeficiency virus (HIV) infection continues to be a leading cause of morbidity and mortality. HIV-infected individuals are now surviving for a relatively longer period and this is because of easy accessibility to antiretroviral therapy these days. As a result, chronic disease-related complications are now being recognized more often. Kidney disease in HIV-infected children can vary from glomerular to tubular-interstitial involvement. We searched the database to identify various kidney diseases seen in HIV-infected children. We describe the epidemiology, pathogenesis, pathology, clinical and laboratory manifestations, management and outcome of commonly seen kidney disease in HIV-infected children. We also provide a brief overview of toxicity of antiretroviral drugs seen in HIV-infected children. Kidney involvement in HIV-infected children may arise because of HIV infection per se, opportunistic infections, immune mediated injury and drug toxicity. HIV-associated nephropathy is perhaps the most common and most severe form of kidney disease. Proteinuria may be a cost-effective screening test in the long-term management of HIV-infected children, however, there are no definite recommendations for the same. Other important renal diseases are HIV immune complex kidney disease, thrombotic microangiopathy, interstitial nephritis and vasculitis.

Urinary Markers of Tubular Injury in HIV-Infected Patients

Renal disease is a common complication of HIV-infected patients, associated with increased risk of cardiovascular events, progression to AIDS, AIDS-defining illness, and mortality. Early and accurate identification of renal disease is therefore crucial to improve patient outcomes. The use of serum creatinine, along with proteinuria, to detect renal involvement is essentially to screen for markers of glomerular disease and may not be effective in detecting earlier stages of renal injury. Therefore, more sensitive and specific markers are needed in order to early identify HIV-infected patients at risk of renal disease. This review article summarizes some new and important urinary markers of tubular injury in HIV-infected patients and their clinical usefulness in the renal safety follow-up of TDF-treated patients.

Renal abnormalities in a cohort of HIV-infected children and adolescents

BACKGROUND

This study aimed to identify the prevalence of renal abnormalities and the evolution of glomerular filtration rate (GFR) among human immunodeficiency virus (HIV)- infected children and adolescents followed up in an infectious disease outpatient pediatric clinic.

METHODS

We performed a cohort study of 115 children and adolescents. Outcomes of two evaluations for urinalysis, microalbuminuria/urinary creatinine ratio, urinary retinol-binding protein (uRBP) concentration, and estimated GFR (eGFR) were obtained for each patient, with an average interval of 6 months between evaluations. These changes were correlated with gender, age, race, body mass index (BMI), height-for-age (H/A) percentile, clinical and immunological classification of HIV infection, use of antiretroviral therapy (ART), HIV viral load (VL), and CD4+ T-lymphocyte count.

RESULTS

Mean patient age at the time of inclusion in the study was 12.6 ± 3.2 years; 50.4 % were male, 81.7 % had acquired immune defeciency syndrome (AIDS), 80.9 % had CD4+ < 500 cells/mm(3), and 87.8 % were on ART. Urinary changes included hematuria (11.3 %), proteinuria (7 %), and microalbuminuria (11.6 %); uRBP was present in 3.8 %; and mean eGFR was 163 ± 32 ml/min/1.73 m(2).

CONCLUSIONS

The subclinical renal abnormalities found in this study may indicate early manifestations of a broad spectrum of renal dysfunction associated with HIV and involves the decision to initiate or modify ART.

Circulating Fibroblast Growth Factor-2, HIV-Tat, and Vascular Endothelial Cell Growth Factor-A in HIV-Infected Children with Renal Disease Activate Rho-A and Src in Cultured Renal Endothelial Cells

Renal endothelial cells (REc) are the first target of HIV-1 in the kidney. The integrity of REc is maintained at least partially by heparin binding growth factors that bind to heparan sulfate proteoglycans located on their cell surface. However, previous studies showed that the accumulation of two heparin-binding growth factors, Vascular Endothelial Cell Growth Factor-A (VEGF-A) and Fibroblast Growth Factor-2 (FGF-2), in combination with the viral protein Tat, can precipitate the progression of HIV-renal diseases. Nonetheless, very little is known about how these factors affect the behavior of REc in HIV+ children. We carried out this study to determine how VEGF-A, FGF-2, and HIV-Tat, modulate the cytoskeletal structure and permeability of cultured REc, identify key signaling pathways involved in this process, and develop a functional REc assay to detect HIV+ children affected by these changes. We found that VEGF-A and FGF-2, acting in synergy with HIV-Tat and heparin, affected the cytoskeletal structure and permeability of REc through changes in Rho-A, Src, and Rac-1 activity. Furthermore, urine samples from HIV+ children with renal diseases, showed high levels of VEGF-A and FGF-2, and induced similar changes in cultured REc and podocytes. These findings suggest that FGF-2, VEGF-A, and HIV-Tat, may affect the glomerular filtration barrier in HIV+ children through the induction of synergistic changes in Rho-A and Src activity. Further studies are needed to define the clinical value of the REc assay described in this study to identify HIV+ children exposed to circulating factors that may induce glomerular injury through similar mechanisms.

Urinary biomarkers of kidney diseases in HIV-infected children

A significant number of children infected with the human immunodeficiency virus 1 (HIV-1) virus all over the world are at risk of developing renal diseases that could have a significant impact on their treatment and quality of life. It is necessary to identify children undergoing the early stages of these renal diseases, as well as the potential renal toxicity that could be caused by antiretroviral drugs, in order to prevent the development of cardiovascular complications and chronic renal failure. This article describes the most common renal diseases seen in HIV-infected children, as well as the value and limitations of the clinical markers that are currently being used to monitor their renal function and histological damage in a noninvasive manner. In addition, we discuss the progress made during the last 10 years in the discovery and validation of new renal biomarkers for HIV-infected children and young adults. Although significant progress has been made during the early phases of the biomarkers discovery, more work remains to be done to validate the new biomarkers in a large number of patients. The future looks promising, however, the new knowledge needs to be integrated and validated in the context of the clinical environment where these children are living.

Renal transplantation in human immunodeficiency virus (HIV)-positive children

Renal transplantation is being performed in adult human immunodeficiency virus (HIV)-positive patients and increasingly in paediatric patients as well. A multidisciplinary team involving an infectious disease professional is required to assist with HIV viral-load monitoring and in choosing the most appropriate highly active antiretroviral therapy (HAART). Drug interactions complicate immunosuppressant therapy and require careful management. The acute rejection rates appear to be similar in adults to those in noninfective transplant recipients. Induction with basiliximab and calcineurin-based immunosuppression appears to be safe and effective in these recipients. Prophylaxis is advised for a variety of infections and may need life-long administration, especially in children. Organ shortage remains a significant problem, and kidneys from deceased HIV-positive donors have been used successfully in a small study population. Overall, with careful planning and close follow-up, successful renal transplantation for paediatric HIV-infected recipients is possible.

The basic domain of HIV-tat transactivating protein is essential for its targeting to lipid rafts and regulating fibroblast growth factor-2 signaling in podocytes isolated from children with HIV-1-associated nephropathy

Podocyte injury has a critical role in the pathogenesis of HIV-associated nephropathy (HIVAN). The HIV-1 transactivator of transcription (Tat), combined with fibroblast growth factor-2 (FGF-2), can induce the dedifferentiation and proliferation of cultured human podocytes. Cellular internalization of Tat requires interactions with heparan sulfate proteoglycans and cholesterol-enriched lipid rafts (LRs). However, the specific distribution of Tat in human podocytes and its ability to associate with LRs have not been documented. Here, we found that Tat is preferentially recruited to LRs in podocytes isolated from children with HIVAN. Furthermore, we identified arginines in the basic domain (RKKRRQRRR) of Tat as essential for (1) targeting Tat to LRs, (2) Tat-mediated increases in the expression of Rho-A and matrix metalloproteinase-9 in LRs, and (3) Tat-mediated enhancement of FGF-2 signaling in human podocytes and HIV-transgenic mouse kidneys and the exacerbation of renal lesions in these mice. Tat carrying alanine substitutions in the basic domain (AKKAAQAAA) remained localized in the cytosol and did not associate with LRs or enhance FGF-2 signaling in cultured podocytes. These results show the specific association of Tat with LRs in podocytes isolated from children with HIVAN, confirm Tat as a regulator of FGF-2 signaling in LRs, and identify the key domain of Tat responsible for promoting these effects and aggravating renal injury in HIV-transgenic mice. Moreover, these results provide a molecular framework for developing novel therapies to improve the clinical outcome of children with HIVAN.

A pilot study of urinary fibroblast growth factor-2 and epithelial growth factor as potential biomarkers of acute kidney injury in critically ill children

BACKGROUND

Acute kidney injury (AKI) increases the morbidity of critically ill children. Thus, it is necessary to identify better renal biomarkers to follow the outcome of these patients. This prospective case-control study explored the clinical value of a urinary biomarker profile comprised of neutrophil gelatinase lipocalin (uNGAL), fibroblast growth factor-2 (uFGF-2), and epidermal growth factor (uEGF) to follow these patients.

METHODS

Urine samples were collected from 21 healthy children, and 39 critically ill children (mean age 7.5 years ± 6.97 SD) admitted to a pediatric intensive care unit with sepsis or requiring extra corporeal membrane oxygenation (ECMO). uNGAL, uFGF-2, and uEGF levels were measured using ELISA kits during the first 24 h of admission to PICU, at peak of illness, and upon resolution of the critical illness.

RESULTS

On admission, the uNGAL and uFGF-2 levels were increased, and the uEGF levels were decreased, in critically ill children with AKI (n = 19) compared to those without AKI (n = 20), and healthy controls. A biomarker score using the combined cut-off values of uNGAL, uFGF-2, and uEGF (AUC = 0.90) showed the highest specificity to identify children with AKI, relative to each biomarker alone. uNGAL and uFGF-2 on admission showed high sensitivity and specificity to predict mortality (AUC = 0.82).

CONCLUSIONS

The biomarker profile comprised of uNGAL, uFGF-2, and uEGF increased the specificity to detect AKI in critically ill children, when compared to each biomarker used alone. uNGAL and uFGF-2 may also predict the risk of death. Further validation of these findings in a large sample size is warranted.

A novel urinary biomarker profile to identify acute kidney injury (AKI) in critically ill neonates: a pilot study

BACKGROUND

The goal of this study was to assess the value of a urinary biomarker profile comprised of neutrophil gelatinase-associated lipocalin (NGAL), fibroblast growth factor-2 (FGF-2), and epidermal growth factor (EGF), to detect acute kidney injury (AKI) in critically ill neonates.

METHODS

We conducted a prospective cohort pilot study of at-risk neonates treated in a level IIIC neonatal intensive care unit (NICU) with therapeutic hypothermia (HT) (n = 25) or extracorporeal membrane oxygenation (ECMO) (n = 10). Urine was collected at baseline, 48 h of illness, and > 24 h post-recovery of their corresponding treatments. Control samples were collected from 27 healthy newborns. The data were expressed as urinary concentrations and values normalized for urinary creatinine. AKI was defined as the presence of oliguria >24 h and/or elevated serum creatinine (SCr), or the failure to improve the estimated creatinine clearance (eCCL) by >50% post-recovery. Non-parametric statistical tests and ROC analyses were used to interpret the data.

RESULTS

Fifteen at-risk newborns had AKI. In the first 48 h of illness, the urinary levels of NGAL and FGF-2 had high sensitivity but poor specificity to identify neonates with AKI. At recovery, low urinary EGF levels identified neonates with AKI with a sensitivity of 74% and specificity of 84%. Overall, in the early stages of a critical illness, the urinary levels of NGAL and FGF-2 were sensitive, but not specific, to identify neonates at risk of AKI. Low EGF levels post-recovery identified critically ill neonates with AKI.

CONCLUSIONS

These findings require validation in larger prospective studies.

Role of circulating fibroblast growth factor-2 in lipopolysaccharide-induced acute kidney injury in mice

Fibroblast growth factor-2 (FGF-2) is an angiogenic growth factor involved in renal growth and regeneration. Previous studies in rodents revealed that single intrarenal injections of FGF-2 improved the outcome of acute kidney injury (AKI). Septic children usually show elevated plasma levels of FGF-2, and are at risk of developing AKI. However, the role of circulating FGF-2 in the pathogenesis of AKI is not well understood. We have developed a mouse model to determine how FGF-2 released into the circulation modulates the outcome of AKI induced by lipopolysaccharide (LPS). Young FVB/N mice were infected with adenoviruses carrying a secreted form of human FGF-2 or control LacZ vectors. Subsequently, when the circulating levels of FGF-2 were similar to those seen in septic children, mice were injected with a non-lethal dose of LPS or control buffer. All mice injected with LPS developed hypotension and AKI, from which they recovered after 5 days. FGF-2 did not improve the outcome of AKI, and induced more significant renal proliferative and apoptotic changes during the recovery phase. These findings suggest that circulating FGF-2 may not necessarily prevent the development or improve the outcome of AKI. Moreover, the renal accumulation of FGF-2 might cause further renal damage.

Advances in our understanding of the pathogenesis of HIV-1 associated nephropathy in children

Childhood HIV-1 associated nephropathy (HIVAN) is a clinical and renal histological disease characterized by heavy proteinuria associated with focal and segmental glomerular sclerosis and/or mesangial hyperplasia in combination with microcystic tubular dilatation. These lesions lead to renal enlargement and rapid progression to kidney failure. Children of African ancestry have a unique susceptibility to developing HIVAN. It is estimated that approximately 300,000 HIV-infected children living in the sub-Saharan Africa could develop HIVAN if they do not receive appropriate antiretroviral therapy. This article discusses recent developments and controversies related to the pathogenesis of childhood HIVAN. The role of host genetic factors, including the newly identified variants in the APOL1 gene, is discussed in the context of previous studies that established the pathological paradigm for HIVAN, and our current understanding of the functional genomics analysis. Hopefully, these advances will provide new research opportunities to generate better treatments for children with HIVAN.

Urinary biomarkers: the future looks promising

Soler-García and collaborators show that changing levels of urinary biomarkers associated with the pathology of HIV-associated nephropathy may identify HIV-infected children at greatest risk for this complication. These changes appear relatively early in disease progression and remain responsive to antiviral therapy. Will these trends be borne out in a multicenter study?