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

Notch3 deletion regulates HIV-1 gene expression and systemic inflammation to ameliorate chronic kidney disease

Antiretroviral therapy (ART) has profoundly decreased HIV-1 associated morbidity. However, despite ART, immune cells remain latently infected and slowly release viral proteins, leading to chronic inflammation and HIV associated comorbidities. Thus, new strategies are needed to reduce the inflammatory effects of HIV-1. In previous studies we found that gamma secretase inhibitor (GSIXX) ameliorated renal lesions of HIV-Tg26 mice carrying replication defective HIV-1 PNL4-3 by inhibiting Notch activation. Since gamma secretase inhibition is not a safe strategy in humans, here we examined the specific role of the Notch3 pathway in the pathogenesis of the renal lesions and outcome of HIV-Tg26 mice. We found that Notch3 is activated in podocytes and other renal cells in HIV-Tg26 mice and human biopsies with HIV-1 associated Nephropathy (HIVAN). Knockdown of Notch3 in HIV-Tg26 mice revealed a marked reduction in the mortality rate, improvement in renal injury and function. RNA sequencing and immunolabeling data revealed that Notch3 deletion drastically reduced infiltrating renal macrophages in HIV-Tg-N3KO mice in association with renal reduction of HIV-nef mRNA expression levels. In fact, bone marrow derived macrophages from HIV-Tg26 mice showed a significant activation of Notch3 signaling. Further, systemic levels of TNF-alpha and MCP-1 and other inflammatory chemokines and cytokines were reduced in Tg-N3KO mice as compared to HIV-Tg26 mice and this translated to a marked reduction of HIV-induced skin lesions. Taken together, these studies strongly point to a dual inhibitory/therapeutic effect of Notch3 inhibition on HIV-induced systemic, skin and renal lesions independently of ART.

Notch4 activation aggravates NF-κB-mediated inflammation in HIV-1-associated nephropathy

Notch pathway activation plays a central role in the pathogenesis of many glomerular diseases. We have previously shown that Notch4 expression was upregulated in various renal cells in human immunodeficiency virus (HIV)-associated nephropathy (HIVAN) patients and rodent models of HIVAN. In this study, we examined whether the Notch pathway can be distinctly activated by HIV-1 gene products and whether Notch4, in particular, can influence disease progression. Using luciferase reporter assays, we did not observe activation of the NOTCH4 promoter with the HIV protein Nef in podocytes. Further, we observed upregulated expression of a gamma secretase complex protein, presenilin 1, but not Notch4, in podocytes infected with an HIV-1 expression construct. To assess the effects of Notch4 on HIVAN disease progression, we engineered Tg26 mice with global deletion of the Notch4 intracellular domain (Notch4^dl), which is required for signaling function. These mice (Notch4^d1/Tg26⁺) showed a significant improvement in renal function and a significant decrease in mortality compared to Tg26 mice. Histological examination of kidneys showed that Notch4^d1/Tg26⁺ mice had overall glomerular, tubulointerstitial injury and a marked decrease in interstitial inflammation. A significant decrease in the proliferating cells was observed in the tubulointerstitial compartments of Notch4^d1/Tg26⁺ mice. Consistent with the diminished inflammation, kidneys from Notch4^d1/Tg26⁺ mice also showed a significant decrease in expression of the inflammatory cytokine transcripts Il-6 and Ccl2, as well as the master inflammatory transcription factor NF-κB (Nfkb1 transcripts and p65 protein). These data identify Notch4 as an important mediator of tubulointerstitial injury and inflammation in HIVAN and a potential therapeutic target.

Summary: Notch4 activation contributes to the inflammation seen in HIV-associated nephropathy (HIVAN), and inhibition of Notch4 ameliorates inflammation and prolongs life in a mouse model of HIVAN.

HIV-associated immune complex kidney disease

The introduction in the late 20(th) century of combination antiretroviral therapy (cART) to treat patients infected with HIV has changed the natural history of the disease from an acute illness that rapidly culminates in death, to a chronic condition that can be managed with medications. Over the past decade the epidemiology of kidney disease in US patients infected with HIV has changed, perhaps because of the increased availability and use of cART. Patients with HIV infection exhibit unique immunologic characteristics, including immunodeficiency and dysregulation of immunoglobulin synthetic responses and T-cell function, which can result in glomerular immune complex deposition and subsequent kidney injury. This Review examines the differential diagnoses of HIV-associated immune complex kidney diseases (HIVICD), and discusses the clinical manifestations and mechanisms underlying their development. We address the issues associated with treatment, clinical outcomes, and research needs to enhance our ability to diagnose and optimally treat patients with HIVICD.

Advances in the pathogenesis of HIV-associated kidney diseases

Despite improved outcomes among persons living with HIV who are treated with antiretroviral therapy, they remain at increased risk for acute and chronic kidney diseases. Moreover, since HIV can infect renal epithelial cells, the kidney might serve as a viral reservoir that would need to be eradicated when attempting to achieve full virologic cure. In recent years, much progress has been made in elucidating the mechanism by which HIV infects renal epithelial cells and the viral and host factors that promote development of kidney disease. Polymorphisms in APOL1 confer markedly increased risk of HIV-associated nephropathy; however, the mechanism by which ApoL1 variants may promote kidney disease remains unclear. HIV-positive persons are at increased risk of acute kidney injury, which may be a result of a high burden of subclinical kidney disease and/or viral factors and frequent exposure to nephrotoxins. Despite the beneficial effect of antiretroviral therapy in preventing and treating HIVAN, and possibly other forms of kidney disease in persons living with HIV, some of these medications, including tenofovir, indinavir, and atazanavir can induce acute and/or chronic kidney injury via mitochondrial toxicity or intratubular crystallization. Further research is needed to better understand factors that contribute to acute and chronic kidney injury in HIV-positive patients and to develop more effective strategies to prevent and treat kidney disease in this vulnerable population.

Chronic kidney disease after liver transplantation in human immunodeficiency virus/hepatitis C virus-coinfected recipients versus human immunodeficiency virus-infected recipients without hepatitis C virus: results from the National Institutes of Health multi-site study

Hepatitis C virus (HCV) and human immunodeficiency virus (HIV) are both associated with chronic kidney disease (CKD), a major complication after orthotopic liver transplantation (OLT). The aim of this study was to assess predictors of post-OLT CKD in HIV/HCV-coinfected recipients versus HIV-infected recipients without HCV (HIV/non-HCV recipients). Data from a National Institutes of Health study of 116 OLT recipients (35 HIV/non-HCV recipients and 81 HIV/HCV-coinfected recipients) from 2003 to 2010 (Solid Organ Transplantation in HIV: Multi-Site Study) were analyzed for the pretransplant CKD prevalence [estimated glomerular filtration rate (eGFR) < 60 mL/minute for ≥3 months] and the incidence of CKD up to 3 years posttransplant. Proportional hazards models were performed to assess predictors of posttransplant CKD. A contemporaneous cohort of HCV-monoinfected transplant recipients from the Scientific Registry of Transplant Recipients database was also analyzed. The median age at transplant was 48 years, the median serum creatinine level was 1.1 mg/dL, and the median eGFR was 77 mL/minute. Thirty-four patients were suspected to have pretransplant CKD; 20 of these patients (59%) had posttransplant CKD. Among the 82 patients without pretransplant CKD (26 HIV/non-HCV patients and 56 HIV/HCV-coinfected patients), the incidence of stage 3 CKD 3 years after OLT was 62% (55% of HIV/non-HCV patients and 65% of HIV/HCV-coinfected patients), and the incidence of stage 4/5 CKD was 8% (0% of HIV/non-HCV patients and 12% of HIV/HCV-coinfected patients). In a multivariate analysis, older age [[hazard ratio (HR) = 1.05 per year, P = 0.03] and the CD4 count (HR = 0.90 per 50 cells/μL, P = 0.01) were significant predictors of CKD. HCV coinfection was significantly associated with stage 4/5 CKD (HR = 10.8, P = 0.03) after adjustments for age. The cumulative incidence of stage 4/5 CKD was significantly higher for HIV/HCV-coinfected patients versus HIV/non-HCV transplant recipients and HCV-monoinfected transplant recipients (P = 0.001). In conclusion, CKD occurs frequently in HIV-infected transplant recipients. Predictors of posttransplant CKD include older age and a lower posttransplant CD4 count. HCV coinfection is associated with a higher incidence of stage 4/5 CKD.

Tubulointerstitial nephropathies in HIV-infected patients over the past 15 years: a clinico-pathological study

BACKGROUND AND OBJECTIVES

The therapy and outcome of HIV infection have dramatically changed over the last 15 years, resulting in a change in renal complications. This study analyzed the characteristics of HIV-infected patients and biopsy-proven tubulointerstitial nephropathies to define disease patterns and therapeutic implications.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A clinico-pathologic retrospective study of 59 consecutive renal biopsies showing predominant tubular and/or interstitial lesions in HIV-infected patients referred to the nephrology department between 1995 and 2011 was performed. HIV-associated nephropathy and vascular diseases were excluded from the study.

RESULTS

Tubulointerstitial nephropathies accounted for 26.6% of 222 native renal biopsies performed in HIV-infected patients. Two pathologic groups were analyzed, tubulopathy and interstitial nephritis, which represented 49% and 51% of tubulointerstitial nephropathies, respectively. Most patients presented with AKI (76.3%) and high-grade proteinuria (57.7%). Drug-related nephrotoxicity was the leading cause (52.5%). Alternative etiologies included infections (15.2%), dysimmune disorders (8.5%), malignancies (3.4%), and chronic (10.2%) and acute (10.2%) tubulointerstitial nephropathies of undetermined origin. Tubulopathy was strongly associated with antiretroviral drug toxicity (75.9%) and mostly caused by tenofovir (55.2%), which was associated with proximal tubular dysfunction (87.5%), overt Fanconi's syndrome (37.5%), and nephrogenic diabetes insipidus (12.5%). Interstitial nephritis was associated with a broader spectrum of pathologic lesions and etiologies.

CONCLUSIONS

In this series, tubulointerstitial nephropathies accounted for 26.6% of renal diseases in HIV-infected patients. Considering the therapeutic implications of diagnoses of drug toxicity, infection, and dysimmune syndromes, this study underscores the importance of monitoring renal parameters in HIV-infected patients and points to the relevance of kidney biopsy to allow an accurate diagnosis.

Chronic kidney disease associated with perinatal HIV infection in children and adolescents

BACKGROUND

This study describes the incidence, clinical and demographic characteristics, and spectrum of chronic kidney disease (CKD) in youths with perinatal HIV-1 infection.

METHODS

Retrospective analysis between May 1993 and December 2006 of subjects with renal disease followed in the Pediatric AIDS Clinical Trials Group 219/219C multicenter study examining the long-term consequences of perinatal HIV infection. Diagnosis confirmation was made utilizing a questionnaire mailed to research sites. Participants with CKD of other etiology than HIV were excluded. Outcome measures were biopsy-diagnosed CKD and, in the absence of biopsy, HIV-associated nephropathy (HIVAN) using established clinical criteria.

RESULTS

Questionnaires on 191 out of 2,102 participants identified 27 cases of CKD: 14 biopsy-diagnosed and 6 clinical cases of HIVAN, and 7 biopsy-diagnosed cases of immune complex-mediated kidney disease (lupus-like nephritis, 3; IgA nephropathy, 2; membranous nephropathy, 2). Incidence rates for CKD associated with HIV in pre-highly active antiretroviral therapy (HAART) (1993-1997) and HAART (1998-2002, 2003-2006) eras were 0.43, 2.84, and 2.79 events per 1,000 person years respectively. In multivariate analysis, black race and viral load ≥100,000 copies/mL (rate ratios 3.28 and 5.05, p ≤ 0.02) were associated with CKD.

CONCLUSIONS

A variety of immune complex-mediated glomerulonephritides and HIVAN occurs in this population. Black race and uncontrolled viral replication are risk factors for CKD associated with HIV.

Moving from viral suppression to comprehensive patient-centered care: the high prevalence of comorbid conditions and health risk factors in HIV-1-infected patients in Australia

HIV clinicians today need to move from focusing on viral suppression to a chronic disease model in which comorbid conditions and risk factors are comprehensively identified and addressed to reduce rates of serious non-AIDS-related morbidity and mortality. This study aimed to determine the prevalence of comorbid conditions in an Australian HIV-positive population. Of 180 patients included, there was a median CD4 count of 0.520 cells/mm(3). The majority (88%) of patients were currently receiving highly active antiretroviral therapy (HAART). There were high rates of failure to attend clinical appointments (30%), current smoking (42%), hypertension (16%), and dyslipidemia (17%). Significant rates of dipstick-positive proteinuria (16%) and elevated blood glucose (15%) were recorded. Risk factors were commonly not addressed by the treating clinician. There is an urgent need to systematize detection and management of high-prevalence comorbid conditions to prevent premature mortality associated with serious non-AIDS events.

Expert opinion on pharmacotherapy of kidney disease in HIV-infected patients

INTRODUCTION

Human immunodeficiency virus (HIV) infection is associated with the development of a wide spectrum of kidney diseases. HIV-associated nephropathy (HIVAN) is the most common cause of chronic kidney disease (CKD) in HIV-infected individuals and predominantly affects patients of African ancestry. HIVAN is a leading cause of end-stage renal disease (ESRD) among African-Americans.

AREAS COVERED

An overview of the spectrum of kidney disease in patients with HIV is given. Current pharmacologic interventions to treat kidney disease in HIV are discussed. This review will enhance knowledge regarding the most common causes of kidney disease in HIV-infected patients. An understanding of the principles related to pharmacotherapy in HIV-infected patients with kidney disease will also be gained.

EXPERT OPINION

Kidney disease is an important cause of morbidity and mortality in HIV-infected patients. The most common cause of chronic kidney disease in this population is HIV-associated nephropathy, which is caused by viral infection of the renal epithelium. Several medications that are commonly used in HIV-infected patients can have adverse effects on the kidneys and the doses of many antiretroviral medications need to be adjusted in patients with impaired renal function.