Treatment-limiting renal tubulopathy in patients treated with tenofovir disoproxil fumarate

HIV-associated kidney disease: the changing spectrum and treatment priorities

PURPOSE OF REVIEW

This review examines the impact of HIV on kidney disease, which remains significant despite advances in antiretroviral therapy (ART). The review is timely due to the shifting epidemiology of kidney disease in people with HIV (PWH), driven by increased ART access, noncommunicable diseases, and region-specific opportunistic infections like tuberculosis.

RECENT FINDINGS

The literature highlights a decline in HIV-associated nephropathy (HIVAN) and a rise in tubulointerstitial diseases and noncommunicable diseases among PWH. Studies from the United States and South Africa report decreased HIVAN prevalence and increased rates of tubulointerstitial diseases linked to tenofovir disoproxil fumarate (TDF) toxicity and tuberculosis (TB). Immune complex glomerulonephritis (ICGN) and diabetic kidney disease (DKD) are also prevalent.

SUMMARY

The findings underscore the need for improved diagnostic tools for opportunistic infections, management of ART-related complications, and strategies to address noncommunicable diseases in PWH. There is a need to centralize care to address all health needs simultaneously. Future research should focus on APOL1-targeted therapies and the role of SGLT2 inhibitors in CKD. Enhanced transplantation outcomes and the development of guidelines for managing DKD in PWH are critical for advancing clinical practice and improving patient outcomes.

Safety of tenofovir alafenamide in people with HIV who experienced proximal renal tubulopathy on tenofovir disoproxil

Twenty-eight individuals who experienced proximal renal tubulopathy (PRT, Fanconi syndrome) while receiving tenofovir disoproxil initiated tenofovir alafenamide (TAF) and were followed for 5 years. None developed recurrent PRT or experienced significant changes in estimated glomerular filtration rate (by creatinine or cystatin-C), albuminuria, proteinuria, retinol-binding proteinuria, fractional excretion of phosphate, alkaline phosphatase, or bone mineral density at the lumbar spine. These data suggest that TAF is a well tolerated treatment option for individuals vulnerable to developing PRT.

Higher prevalence of kidney function impairment among older people living with HIV in Uganda

Background

People living with HIV (PLWH) are at risk of kidney function impairment due to HIV-related inflammation, antiretroviral therapy (ART), diabetes mellitus, and hypertension. Older persons may experience a higher burden of chronic kidney disease (CKD) as kidney function declines with increasing age. There is a paucity of data comparing the prevalence of kidney function impairment in older PLWH to that in HIV-uninfected people in sub-Saharan Africa.

Methods

We conducted a cross-sectional study among people aged ≥ 60 years living with and without HIV in Kampala, Uganda who were matched 1:1 by community location. We collected data on sociodemographics, comorbidities, and HIV-related clinical characteristics. We defined kidney function impairment as an estimated glomerular filtration rate(eGFR) < 60mls/min/1.73m2 with or without proteinuria. We constructed multivariable logistic regression models to study associations between participant characteristics and kidney function impairment.

Results

We enrolled 278 people (median age 66 years); 50% were PLWH, and 51.8% were female. Overall, the prevalence of kidney function impairment was 23.0% (95% CI:18.4%-28.4%); 33.1% (95% CI: 25.7%-41.4%) versus 12.9% (95% CI: 8.3%-19.7%) among people living with and without HIV (p-value < 0.01). The prevalence of proteinuria among PLWH versus people without HIV was 43.9% (95% CI:35.8%-52.3%) versus 19.4% (95% CI:13.6%-26.9%) p-value < 0.01. Living with HIV (OR = 3.89(95% CI: 2.04-7.41), p-value < 0.01), older age (OR = 1.13, (95% CI:1.07-1.20), p-value < 0.01), female sex (OR = 1.95, (95% CI:1.06-3.62), p-value = 0.03) and a prior diagnosis of hypertension (OR = 2.19(95% CI:1.02-4.67), p-value = 0.04) were significantly associated with kidney function impairment.

Conclusions

HIV infection is strongly associated with kidney function impairment among older PLWH. Prioritizing routine measurements of kidney function and proteinuria in older PLWH will enable early detection and institution of measures to reduce the progression of kidney disease.

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.

Renal outcomes in adults with HBV, HIV and HBV/HIV coinfection after 3 years of antiviral therapy in urban Tanzania

BACKGROUND

An enhanced understanding of renal outcomes in persons with chronic HBV, HIV, and HBV/HIV coinfection is needed to mitigate chronic kidney disease in regions where HBV and HIV are endemic.

OBJECTIVES

To investigate changes in estimated glomerular filtration rate (eGFR) in adults with HBV, HIV or HBV/HIV enrolled in a 3 year prospective cohort study of liver outcomes in Dar es Salaam, Tanzania and initiated on antiviral therapy.

METHODS

We compared eGFR between and within groups over time using mixed-effects models.

RESULTS

Four hundred and ninety-nine participants were included in the analysis (HBV: 164; HIV: 271; HBV/HIV: 64). Mean baseline eGFRs were 106.88, 106.03 and 107.18 mL/min/1.73 m2, respectively. From baseline to Year 3, mean eGFR declined by 4.3 mL/min/1.73 m2 (95% CI -9.3 to 0.7) and 3.7 (-7.8 to 0.5) in participants with HBV and HIV, respectively, and increased by 5.1 (-4.7 to 14.9) in those with HBV/HIV. In multivariable models, participants with HBV had lower eGFRs compared with those with HIV or HBV/HIV and, after adjusting for HBV DNA level and hepatitis B e antigen (HBeAg) status, significantly lower eGFRs than those with HBV/HIV at all follow-up visits.

CONCLUSIONS

In this Tanzanian cohort, coinfection with HBV/HIV did not appear to exacerbate renal dysfunction compared with those with either infection alone. Although overall changes in eGFR were small, persons with HBV experienced lower eGFRs throughout follow-up despite their younger age and similar baseline values. Longer-term studies are needed to evaluate continuing changes in eGFR and contributions from infection duration and other comorbidities.

Effect of P-glycoprotein and Cotreatment with Sofosbuvir on the Intestinal Permeation of Tenofovir Disoproxil Fumarate and Tenofovir Alafenamide Fumarate

PURPOSE

We aimed to compare the effects of P-glycoprotein (ABCB1) on the intestinal uptake of tenofovir disoproxil fumarate (TDF), tenofovir alafenamide fumarate (TAF), and metabolites, tenofovir isoproxil monoester (TEM) and tenofovir (TFV), and to study the molecular mechanism of drug-drug interaction (DDI) between sofosbuvir (SOF) and TDF/TAF.

METHODS

Bidirectional transport experiments in Caco-2 cells and accumulation studies in precision-cut intestinal slices prepared from the ileal segment of rodent (rPCIS) and human (hPCIS) intestines were performed.

RESULTS

TDF and TAF were extensively metabolised but TAF exhibited greater stability. ABCB1 significantly reduced the intestinal transepithelial transfer and uptake of the TFV(TDF) and TFV(TAF)-equivalents. However, TDF and TAF were absorbed more efficiently than TFV and TEM. SOF did not inhibit intestinal efflux of TDF and TAF or affect intestinal accumulation of TFV(TDF) and TFV(TAF)-equivalents but did significantly increase the proportion of absorbed TDF.

CONCLUSIONS

TDF and TAF likely produce comparable concentrations of TFV-equivalents in the portal vein and the extent of permeation is reduced by the activity of ABCB1. DDI on ABCB1 can thus potentially affect TDF and TAF absorption. SOF does not inhibit ABCB1-mediated transport of TDF and TAF but does stabilise TDF, albeit without affecting the quantity of TFV(TDF)-equivalents crossing the intestinal barrier. Our data thus suggest that reported increases in the TFV plasma concentrations in patients treated with SOF and TDF result either from a DDI between SOF and TDF that does not involve ABCB1 or from a DDI involving another drug used in combination therapy.

Broadening access to tenofovir alafenamide for the treatment and prevention of HIV-1 infection

INTRODUCTION

Tenofovir alafenamide (TAF), a prodrug of tenofovir, achieves higher intracellular concentrations of tenofovir-diphosphate and 90% lower plasma concentrations of tenofovir compared to tenofovir disoproxil fumarate (TDF). TAF is associated with improved renal and bone safety outcomes.

AREAS COVERED

We review the efficacy and safety of TAF-containing regimens in adults and pediatrics. We highlight safety data during pregnancy, drug interactions during co-administration with tuberculosis treatment, and critical knowledge gaps to be addressed for the successful implementation of TAF in low- and middle-income countries. We performed a search on MEDLINE PubMed and conference websites for relevant articles published from January 2010 to March 2023.

EXPERT OPINION

Current evidence demonstrates that TAF has similar efficacy and tolerability, superior bone and renal safety, and higher rates of dyslipidemia and weight gain, compared with TDF. However, there are several knowledge gaps, in specific sub-populations, that require action. Emerging data suggests that TAF is safe during pregnancy, although fuller safety data to support TAF use in pregnancy is needed. Similarly, there is a lack of evidence that TAF can be used in combination with rifamycin-based tuberculosis treatment in PWH and TB. Further studies are needed to fill knowledge gaps and support the wider rollout of TAF.

Pharmacogenetics of tenofovir renal toxicity in HIV-positive Southern Africans

OBJECTIVE

Renal toxicity is more common with tenofovir disoproxil fumarate (TDF) than with tenofovir alafenamide fumarate (TAF). We investigated whether polymorphisms in genes relevant to tenofovir disposition affect renal toxicity among HIV-positive Southern Africans.

METHODS

Genetic sub-study of adults randomized to initiate TAF or TDF together with dolutegravir and emtricitabine was conducted. Outcomes were changes from week 4 to 48 in the estimated glomerular filtration rate (eGFR) and from baseline to week 48 in urine retinol-binding protein and urine β2-microglobulin adjusted for urinary creatinine (uRBP/Cr and uB2M/Cr). Primary analyses prioritized 14 polymorphisms previously reported to be associated with tenofovir disposition or renal outcomes, and all polymorphisms in 14 selected genes. We also explored genome-wide associations.

RESULTS

336 participants were enrolled. Among 14 polymorphisms of primary interest, the lowest P values for change in eGFR, uRBP/Cr, and uB2M/Cr were ABCC4 rs899494 ( P  = 0.022), ABCC10 rs2125739 ( P  = 0.07), and ABCC4 rs1059751 ( P  = 0.0088); and in genes of interest, the lowest P values were ABCC4 rs4148481 ( P  = 0.0013), rs691857 ( P  = 0.00039), and PKD2 rs72659631 ( P  = 0.0011). However, none of these polymorphisms withstood correction for multiple testing. Genome-wide, the lowest P values were COL27A1 rs1687402 ( P  = 3.4 × 10 -9 ), CDH4 rs66494466 ( P  = 5.6 × 10 -8 ), and ITGA4 rs3770126 ( P  = 6.1 × 10 -7 ).

CONCLUSION

Two ABCC4 polymorphisms, rs899494 and rs1059751, were nominally associated with change in eGFR and uB2M/Cr, respectively, albeit in the opposite direction of previous reports. COL27A1 polymorphism was genome-wide significantly associated with change in eGFR.

Antibody interventions in HIV: broadly neutralizing mAbs in children

PURPOSE OF REVIEW

Treatment strategies for children with HIV are evolving, with considerations beyond plasma viremic control that raise the possibility of reducing or eliminating latent reservoirs to achieve posttreatment control. Novel strategies that maintain HIV viral suppression and allow time off small molecule antiretroviral therapy (ART) are of high priority. Trials with broadly neutralizing mAbs (bNAbs) have begun in children and may become a viable alternative treatment option. Recent bNAb treatment studies in adults indicate that bNAbs may be associated with a reduction in viral reservoirs, providing optimism that these agents may provide a pathway towards posttreatment control that rarely occurs with small molecule ART.

RECENT FINDINGS

Children with HIV provide an ideal opportunity to study bNAbs as an alternative treatment strategy that reduces direct ART toxicities during critical periods of growth and development, allows time off ART and takes advantage of the distinct features of the developing immune system in children that could facilitate induction of more potent autologous cellular and humoral immune responses against HIV-1. To date, paediatric bNAb studies with reported results include IMPAACT P1112, IMPAACT 2008, IMPAACT P1115 and the Tatelo study, and these results will be reviewed.

SUMMARY

In this review, we summarize the current and planned paediatric bNAb studies, with an emphasis on trial results available to date. We highlight the potential benefits of immune-based therapies for the maintenance of viral suppression and its potential for achieving viral remission in children living with HIV.

The Evolving Spectrum of Kidney Histology in HIV-Positive Patients in South Africa

Introduction

Sub-Saharan Africa remains challenged by the highest burden of human immunodeficiency virus (HIV), an epidemic of tuberculosis (TB), and increasing number of people with HIV (PWH) on antiretroviral therapy (ART), all of which may result in kidney injury.

Methods

This observational cohort study describes the spectrum of kidney disease in PWH in South Africa, between 2005 and 2020. Kidney biopsies were analyzed in 4 time periods as follows: early ART rollout (2005-2009), tenofovir disoproxil (TDF) introduction (2010-2012), TDF-based fixed dose combination (2013-2015), and ART at HIV diagnosis (2016-2020). Logistic regression was used to identify factors associated with HIV-associated nephropathy or focal segmental glomerulosclerosis (HIVAN/FSGS) and tubulointerstitial disease (TID).

Results

We included 671 participants (median age 36, interquartile range, 21-44 years; 49% female; median CD4 cell count 162 [interquartile range, 63-345] cells/mm3). Over time, ART (31%-65%, P < 0.001), rate of HIV suppression (20%-43%, P < 0.001), nonelective biopsies (53%-72%, P < 0.001), and creatinine at biopsy (242-449 μmol/l, P < 0.001) increased. A decrease in HIVAN (45%-29% P < 0.001) was accompanied by an increase in TID (13%-33%, P < 0.001). Granulomatous interstitial nephritis accounted for 48% of TID, mostly because of TB. Exposure to TDF was strongly associated with TID (adjusted odds ratio 2.99, 95% confidence interval 1.89-4.73 P < 0.001).

Conclusion

As ART programs intensified and increasingly used TDF, the spectrum of kidney histology in PWH evolved from a predominance of HIVAN in the early ART era to TID in recent times. The increase in TID is likely due to multiple exposures that include TB, sepsis, and TDF as well as other insults.

Integration of High-Throughput Imaging and Multiparametric Metabolic Profiling Reveals a Mitochondrial Mechanism of Tenofovir Toxicity

Nephrotoxicity is a major cause of kidney disease and failure in drug development, but understanding of cellular mechanisms is limited, highlighting the need for better experimental models and methodological approaches. Most nephrotoxins damage the proximal tubule (PT), causing functional impairment of solute reabsorption and systemic metabolic complications. The antiviral drug tenofovir disoproxil fumarate (TDF) is an archetypal nephrotoxin, inducing mitochondrial abnormalities and urinary solute wasting, for reasons that were previously unclear. Here, we developed an automated, high-throughput imaging pipeline to screen the effects of TDF on solute transport and mitochondrial morphology in human-derived RPTEC/TERT1 cells, and leveraged this to generate realistic models of functional toxicity. By applying multiparametric metabolic profiling-including oxygen consumption measurements, metabolomics, and transcriptomics-we elucidated a highly robust molecular fingerprint of TDF exposure. Crucially, we identified that the active metabolite inhibits complex V (ATP synthase), and that TDF treatment causes rapid, dose-dependent loss of complex V activity and expression. Moreover, we found evidence of complex V suppression in kidney biopsies from humans with TDF toxicity. Thus, we demonstrate an effective and convenient experimental approach to screen for disease relevant functional defects in kidney cells in vitro, and reveal a new paradigm for understanding the pathogenesis of a substantial cause of nephrotoxicity.

The Effects of the COVID-19 Pandemic on Clinical and Laboratory Follow-up of Patients Diagnosed With Chronic Hepatitis B: A Multicenter, Prospective, Observational Study

Background: Chronic hepatitis B (CHB) patients who are under the treatment of antiviral agents should be monitored in routine control visits. However, during the COVID-19 pandemic, the visits were interrupted. Objectives: This study aimed to investigate whether these patients were affected regarding clinical, laboratory, and treatment outcomes. Methods: This prospective study consisted of CHB patients aged > 18 who were applied to 3 tertiary centers between 14 February and 30 March 2022. The patients were selected from the ones who regularly applied to outpatient clinics and under the treatment of antiviral agents before the pandemic. The demographic and laboratory values, including serologic, biochemistry, and molecular results, were compared between the 2 groups who came and did not come to control visits. Results: A total number of 220 patients were included. More than half (n = 142, 64.5%) were female. The median age was 44 years (19 - 73). A hundred and forty-two (64.5%) patients did not come to control visits during the pandemic. The most common reason was anxiety about COVID-19. The tenofovir treatment was replaced with entecavir (ETV) due to osteopenia and with alafenamide due to osteopenia and/or renal failure. The previous agents were re-started in 27 (79.5%) patients who discontinued the treatment. Conclusions: The COVID-19 pandemic negatively impacted the follow-up of CHB patients. In this regard, 15.5% of patients stopped their treatments. The patients who stopped their follow-ups and continued tenofovir disoproxil fumarate (TDF) had proteinuria and decreases in bone mineral density (BMD) and estimated glomerular filtration rate (eGFR) levels.

Short-term oral pre-exposure prophylaxis against HIV-1 modulates the transcriptome of foreskin tissue in young men in Africa

Whilst short-term oral pre-exposure prophylaxis (PrEP) with antiretroviral drugs in men who have sex with men has shown protection against HIV-1 infection, the impact of this regimen on the in vivo foreskin transcriptome is unknown. We collected foreskin tissue after voluntary medical male circumcision from 144 young men (72 from Uganda and 72 from South Africa) randomized to one to two doses of either oral tenofovir (TFV) disoproxil fumarate (FTC-TDF) or tenofovir alafenamide (FTC-TAF) or no drug (untreated controls). This novel approach allowed us to examine the impact of short-term oral PrEP on transcriptome of the male genital tract. A single dose of FTC-TDF did not affect the foreskin transcriptome in relation to control arm, however one dose of FTC-TAF induced upregulation of four genes AKAP8, KIAA0141, HSCB and METTL17. Following two doses of either FTC-TDF or FTC-TAF, there was an increase in 34 differentially expressed genes for FTC-TDF and 15 for FTC-TAF, with nine DEGs in common: KIAA0141, SAFB2, CACTIN, FXR2, AKAP8, HSCB, CLNS1A, DDX27 and DCAF15. Functional analysis of differentially expressed genes revealed modulation of biological processes related to mitochondrial stress (KIAA0141, HSCB and METTL17), anti-viral and anti-inflammatory pathways (CACTIN and AKAP8). Our results show that short-course on-demand oral PrEP in men modulates genes in foreskin tissue which are likely unfavorable to HIV acquisition and replication. We also describe an upregulated expression of genes involved in diverse mitochondria biology which may potentially result in worsened mitochondria-related. These results warrant further studies to assess the role of short-course and prolonged oral PrEP on biological processes of the foreskin mucosa.

The renal-bone axis in older people living with HIV on stable antiretroviral therapy: A sub-analysis of the GS-US-104-0423 study

BACKGROUND

Data on low bone mineral density (BMD) in people living with HIV (PLWH) are mainly derived from younger adults; little is known about how antiretroviral therapy (ART) and alterations in the renal-bone axis relate to BMD in older PLWH.

METHODS

Cross-sectional study of men > 50 years and post-menopausal women with HIV. Antiretroviral therapy exposure was stratified into four groups based on use of tenofovir disoproxil fumarate (TDF) and protease inhibitors (PI): non-TDF/non-PI, non-TDF/PI, TDF/non-PI, and TDF/PI. Bone mineral density was measured by dual X-ray absorptiometry (DXA). Bone turnover/regulatory markers and renal tubular function were analysed in stored plasma and urine samples. The association of ART exposure and bone/renal biomarkers on BMD was explored using logistic regression models.

RESULTS

247 individuals (median [IQR] age 57 [53, 65] years; 47% female; 13% of Black ethnicity; CD4 count 643 [473, 811] cells/mm³; and 98% with HIV RNA < 200 copies/mL) were included. Bone turnover and renal tubular function differed significantly by ART exposure. In analyses adjusted for demographic and traditional renal/bone risk factors, exposure to TDF and PI was associated with a fourfold greater risk of low BMD at the femoral neck and exposure to TDF and/or PI with a threefold greater risk of low BMD at the lumbar spine. The relationship between ART and low BMD was not altered by further adjustment for bone turnover or renal tubular function markers.

CONCLUSIONS

The associations between low BMD and ART exposure (TDF vs. non-TDF and boosted vs. unboosted third agents) were minimally affected by adjustments for bone and kidney biomarkers.

Safety of Tenofovir Alafenamide in People With HIV Who Experienced Proximal Renal Tubulopathy on Tenofovir Disoproxil Fumarate

BACKGROUND

Proximal renal tubulopathy (PRT) is an infrequent complication of tenofovir disoproxil fumarate (TDF). It remains to be established whether tenofovir alafenamide (TAF) can be safely administered to individuals who experienced PRT on TDF.

METHODS

Individuals with a history of TDF-associated PRT and current estimated glomerular filtration rate (eGFR) over 30 mL/min/1.73 m2 initiated TAF and were followed for 96 weeks. The primary outcome of interest was recurrent PRT. Secondary outcomes were changes in kidney biomarkers, bone biomarkers, and bone mineral density (BMD). Data were analyzed using multilevel mixed-effects linear regression models. The trial was registered under EudraCT 2016-003345-29.

RESULTS

All 31 participants [median age 55 (inter-quartile range 51, 60) years, 97% men, 87% White ethnicity] remained on TAF at week 96, and none developed glycosuria or recurrent PRT. Participants experienced small declines in eGFR-creatinine [-1.9 (95% confidence interval: -3.5 to -0.3) mL/min/1.73 m2/yr; P = 0.024], but not in eGFR-cystatin C [-0.9 (-2.1 to 0.4) mL/min/1.73 m2/yr; P = 0.16]. Ten (32%) and 5 (16%) participants experienced rapid (>5 mL/min/1.73 m2/yr) decline in eGFR-creatinine and eGFR-cystatin C. No significant change in other kidney biomarkers, bone turnover, or BMD was observed (P > 0.2).

CONCLUSIONS

In individuals with a history of PRT on TDF, 96 weeks of TAF was not associated with recurrent PRT or adverse effects on renal tubular function, bone turnover, or BMD. These data suggest that TAF is a treatment option for this vulnerable population.

Redefining therapeutic success in HIV patients: an expert view

Thanks to advances in the field over the years, HIV/AIDS has now become a manageable chronic condition. Nevertheless, a new set of HIV-associated complications has emerged, related in part to the accelerated ageing observed in people living with HIV/AIDS, the cumulative toxicities from exposure to antiretroviral drugs over decades and emerging comorbidities. As a result, HIV/AIDS can still have a negative impact on patients' quality of life (QoL). In this scenario, it is reasonable to believe that the concept of therapeutic success, traditionally associated with CD4 cell count restoration and HIV RNA plasma viral load suppression and the absence of drug resistances, needs to be redefined to include other factors that reach beyond antiretroviral efficacy. With this in mind, a group of experts initiated and coordinated the RET Project, and this group, using the available evidence and their clinical experience in the field, has proposed new criteria to redefine treatment success in HIV, arranged into five main concepts: rapid initiation, efficacy, simplicity, safety, and QoL. An extensive review of the literature was performed for each category, and results were discussed by a total of 32 clinicians with experience in HIV/AIDS (4 coordinators + 28 additional experts). This article summarizes the conclusions of these experts and presents the most updated overview on the five topics, along with a discussion of the experts' main concerns, conclusions and/or recommendations on the most controversial issues.

Tenofovir alafenamide nephrotoxicity: a case report and literature review

Background

Tenofovir alafenamide (TAF), a novel prodrug of tenofovir (TFV), has become the preferred drug for the treatment of HIV-1 and chronic hepatitis B infection in clinical practice. Results from clinical trials showed that it had better renal and bone mineral outcomes compared to tenofovir disoproxil fumarate (TDF). However, as we have seen with TDF, side effects from the new medication can be more prevalent and recognized after extensive use in real world situations. Sporadic cases of acute kidney injury in patients using TAF have started to emerge.

Case presentation

We report a case of 49-year-old Thai, HIV treatment-experienced female with hypertension presented with worsening renal function after switching her antiretroviral regimen from TDF, emtricitabine (FTC), and lopinavir/ritonavir (LPV/r) to TAF, FTC and dolutegravir (DTG) for 3 months. Kidney biopsy showed distinctive picture of tenofovir nephrotoxicity with acute tubular injury and mitochondrial injury. The possible causes of acute kidney injury and nephrotoxicity from TAF for this patient were discussed. We have extensively reviewed all published case reports of TAF-associated nephrotoxicity and summarized the essential information in this article.

Conclusion

Although TAF has less nephrotoxicity compared with TDF; renal function should always be monitored after the initiation of both drugs. Future large cohort studies are required to identify the risk factors of TAF-associated nephrotoxicity and to design an effective preventive strategy.

Correcting eGFR for the effects of ART on tubular creatinine secretion: does one size fit all?

Several antiretrovirals including dolutegravir, rilpivirine and cobicistat inhibit tubular creatinine secretion, leading to benign increases in serum creatinine and reductions in estimated glomerular filtration rate (eGFR). This commentary discusses the magnitude and pattern of eGFR decline, whether this can be overcome by applying a standardized correction factor (as reported by Brunet et al. in Antiviral Therapy), the value of serial eGFR measures to detect rapid eGFR decline and the potential utility of cystatin C as an alternative biomarker of kidney function.

Bone mineral density, kidney function, weight gain and insulin resistance in women who switch from TDF/FTC/NNRTI to ABC/3TC/DTG

OBJECTIVES

Tenofovir disoproxil fumarate (TDF) is associated with reduced bone mineral density (BMD). We evaluated changes in BMD in women who switched from TDF, emtricitabine and a nonnucleoside reverse transcriptase inhibitor (TDF/FTC/NNRTI) to abacavir, lamivudine and dolutegravir (ABC/3TC/DTG).

METHODS

We conducted a randomized controlled trial in which women aged ≥40 years were randomized 1:2 to continue TDF/FTC/NNRTI or switch to ABC/3TC/DTG. The primary endpoint was change in total hip BMD measured by dual-energy X-ray absorptiometry at week 48. Secondary endpoints were changes in BMD of the lumbar spine and femoral neck and markers of bone turnover and kidney function up to week 48. We conducted exploratory analyses of weight gain, insulin resistance and metabolic syndrome. Primary and secondary endpoints were analysed by linear regression, with multiple imputation for missing time points.

RESULTS

In all, 91 women [mean age = 50.4 (standard deviation [SD] = 6.6) years, median CD4 cell count = 600 (interquartile range: 479-800) cells/µL] were randomized. Women who switched to ABC/3TC/DTG maintained viral suppression and experienced improvements in total hip BMD (mean adjusted difference = 1%, P = 0.027) and lumbar spine BMD (3%, P = 0.002), with no change in specific markers of bone turnover or renal tubular function. Although participants in the ABC/3TC/DTG arm gained more weight (1.8 kg, P = 0.046), the switch strategy was not associated with reduced insulin sensitivity or new-onset metabolic syndrome.

CONCLUSIONS

Switching from TDF/FTC/NNRTI to ABC/3TC/DTG resulted in improved BMD. Although weight gain was common in women who switched from TDF/FTC/NNRTI to ABC/3TC/DTG, we did not detect adverse effects on glucose homeostasis. Larger studies need to confirm these findings.

Pharmacotherapeutic options for kidney disease in HIV positive patients

INTRODUCTION

Since the developmentof combined antiretroviral therapy (cART), HIV-associated mortality and the incidence of HIV-associated end-stage kidney disease (ESKD) has decreased. However, in the United States, an increase in non-HIV-associated kidney diseases within the HIV-positive population is expected.

AREAS COVERED

In this review, the authors highlight the risk factors for kidney disease within an HIV-positive population and provide the current recommendations for risk stratification and for the monitoring of its progression to chronic kidney disease (CKD), as well as, treatment. The article is based on literature searches using PubMed, Medline and SCOPUS.

EXPERT OPINION

The authors recommend clinicians (1) be aware of early cART initiation to prevent and treat HIV-associated kidney diseases, (2) be aware of cART side effects and discriminate those that may become more nephrotoxic than others and require dose-adjustment in the setting of eGFR ≤ 30ml/min/1.73m², (3) follow KDIGO guidelines regarding screening and monitoring for CKD with a multidisciplinary team of health professionals, (4) manage other co-infections and comorbidities, (5) consider changing cART if drug induced toxicity is established with apparent eGFR decline of ≥ 10ml/min/1.73m² or rising creatinine (≥0.5mg/dl) during drug-drug interactions, and (6) strongly consider kidney transplant in appropriately selected individuals with end stage kidney failure.

Estimated glomerular filtration rate slopes on tenofovir alafenamide

OBJECTIVES

The aim of the study was to analyse and compare estimated glomerular filtration rate (eGFR) slopes during exposure to tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF) in individuals who initiated TAF, regardless of prior regimen, before October 2016.

METHODS

An observational cohort study was conducted at 11 clinics in the UK and Ireland. Mixed effects models with random intercept and time terms fitted were used to generate and compare eGFR slopes while participants were exposed to TDF and TAF, with adjustment for age, eGFR at TDF/TAF initiation, gender, ethnicity, and time-updated CD4 cell count and HIV RNA measurements.

RESULTS

Data were available for 357 subjects (median age 50 years; 80% male; 82% white/other ethnicity; 51% men who have sex with men; median nadir CD4 count 216 cells/µL). The median duration of exposure to TAF was 2.0 (interquartile range 1.6, 2.3) years. At TAF initiation, the median CD4 count was 557 cells/µL, the median eGFR was 80 mL/min/1.73 m², and 86% had suppressed HIV infection. The mean adjusted eGFR slope during TDF and TAF exposure was -2.08 [95% confidence interval (CI) -2.24, -1.92] and 1.18 (95% CI 0.20, 1.52) mL/min/1.73 m²/year, respectively (P < 0.001). Individuals who experienced rapid eGFR decline (> 3 or 5 mL/min/1.73 m²/year) while receiving TDF experienced significant eGFR recovery while on TAF (P < 0.001).

CONCLUSIONS

Significant improvement in eGFR slope was observed in patients who switched from TDF- to TAF-containing antiretroviral regimens. These data provide further support for the renal safety of TAF, and for switching those who experience progressive worsening of renal function from TDF to TAF.

Contemporary issues and new challenges in chronic kidney disease amongst people living with HIV

Chronic kidney disease (CKD) is a comorbidity of major clinical significance amongst people living with HIV (PLWHIV) and is associated with significant morbidity and mortality. The prevalence of CKD is rising, despite the widespread use of antiretroviral therapy (ART) and is increasingly related to prevalent non-infectious comorbidities (NICMs) and antiretroviral toxicity. There are great disparities evident, with the highest prevalence of CKD among PLWHIV seen in the African continent. The aetiology of kidney disease amongst PLWHIV includes HIV-related diseases, such as classic HIV-associated nephropathy or immune complex disease, CKD related to NICMs and CKD from antiretroviral toxicity. CKD, once established, is often relentlessly progressive and can lead to end-stage renal disease (ESRD). Identifying patients with risk factors for CKD, and appropriate screening for the early detection of CKD are vital to improve patient outcomes. Adherence to screening guidelines is variable, and often poor. The progression of CKD may be slowed with certain clinical interventions; however, data derived from studies involving PLWHIV with CKD are sparse and this represent an important area for future research. The control of blood pressure using angiotensin converting enzyme inhibitors and angiotensin receptor blockers, in particular, in the setting of proteinuria, likely slows the progression of CKD among PLWHIV. The cohort of PLWHIV is facing new challenges in regards to polypharmacy, drug-drug interactions and adverse drug reactions. The potential nephrotoxicity of ART is important, particularly as cumulative ART exposure increases as the cohort of PLWHIV ages. The number of PLWHIV with ESRD is increasing. PLWHIV should not be denied access to renal replacement therapy, either dialysis or kidney transplantation, based on their HIV status. Kidney transplantation amongst PLWHIV is successful and associated with an improved prognosis compared to remaining on dialysis. As the cohort of PLWHIV ages, comorbidity increases and CKD becomes more prevalent; models of care need to evolve to meet the new and changing chronic healthcare needs of these patients.

HIV, drugs and the kidney

Human immunodeficiency virus (HIV) affects over 36 million people worldwide. Antiretroviral therapy (ART) is expanding and improving HIV viral suppression, resulting in increasing exposure to drugs and drug interactions. Polypharmacy is a common complication as people are living longer on ART, increasing the risk of drug toxicities. Polypharmacy is related not only to ART exposure and medication for opportunistic infections, but also to treatment of chronic lifestyle diseases. Acute kidney injury (AKI) is frequent in HIV and is commonly the result of sepsis, dehydration and drug toxicities. Furthermore, HIV itself increases the risk of chronic kidney disease (CKD). Drug treatment is often complicated in people living with HIV because of a greater incidence of AKI and/or CKD compared to the HIV-negative population. Impaired renal function affects drug interactions, drug toxicities and importantly drug dosing, requiring dose adjustment. This review discusses ART and its nephrotoxic effects, including drug–drug interactions. It aims to guide the clinician on dose adjustment in the setting of renal impairment and dialysis, for the commonly used drugs in patients with HIV.

Optimizing antiretroviral regimens in chronic kidney disease

PURPOSE OF REVIEW

To identify recent data that inform the management of individuals with HIV and chronic kidney disease.

RECENT FINDINGS

Several nonnucleoside reverse transcriptase, protease, and integrase strand transfer inhibitors inhibit tubular creatinine secretion resulting in stable reductions in creatinine clearance of 5-20 ml/min in the absence of other manifestations of kidney injury. Progressive renal tubular dysfunction is observed with tenofovir disoproxil fumarate in clinical trials, and more rapid decline in estimated glomerular filtration rate in cohort studies of tenofovir disoproxil fumarate and atazanavir, with stabilization, improvement or recovery of kidney function upon discontinuation. Results from clinical trials of tenofovir alafenamide (TAF) in individuals with chronic kidney disease suggest that TAF is well tolerated in those with mild to moderate renal impairment (creatinine clearance >30 ml/min) but results in very high tenofovir exposures in those on haemodialysis.

SUMMARY

Standard antiretroviral regimens remain appropriate for individuals with normal and/or stable, mildly impaired kidney function. In those with chronic kidney disease or progressive decline in estimated glomerular filtration rate, antiretrovirals with nephrotoxic potential should be avoided or discontinued. Although TAF provides a tenofovir formulation for individuals with impaired kidney function, TAF is best avoided in those with severe or end-stage kidney disease.

Early safety of tenofovir alafenamide in patients with a history of tubulopathy on tenofovir disoproxil fumarate: a randomized controlled clinical trial

OBJECTIVES

The aim of the study was to assess the effect of tenofovir alafenamide (TAF) on kidney and bone biomarkers in patients who developed proximal renal tubulopathy (PRT) while receiving tenofovir disoproxil fumarate (TDF).

METHODS

Individuals with a history of TDF-associated PRT and currently suppressed HIV infection on a tenofovir-sparing regimen were randomized 1:1 to continue current antiretroviral therapy or initiate emtricitabine (F)/TAF with discontinuation of nucleoside reverse transcriptase inhibitors (NRTIs) as appropriate. Renal and bone biomarkers were analysed at baseline, week 4 and week 12. The primary outcome was the mean difference between study arms in urine retinol-binding protein:creatinine ratio (RBPCR) change from baseline to week 12. Data were analysed using linear regression, with robust standard errors (primary outcome), and repeated measures mixed effects models (secondary outcomes). The trial was registered under European Union Drug Regulating Authorities Clinical Trials Database 2016-003345-29.

RESULTS

We randomized 31 individuals [mean age 52.4 (standard deviation 0.3) years; 97% male; 90% white); all completed the study. At 12 weeks, there was no difference in change in RBPCR (β 19.6; 95% confidence interval -35.3, 74.5; P = 0.47), and no difference in change in estimated glomerular filtration rate (eGFR) (based on creatinine or cystatin C), albuminuria, proteinuria, renal phosphate or urea handling, (fasting) urine osmolality, parathyroid hormone and bone turnover markers in the control versus the F/TAF exposed groups. No cases of PRT were observed.

CONCLUSIONS

In people with a history of proximal renal tubulopathy while on TDF, 12-week exposure to TAF did not adversely affect renal tubular function. These data support continued evaluation of the long-term safety of TAF in this group of patients.

Chronic Kidney Disease Risk in African and Caribbean Populations With HIV

We conducted an observational cohort study of end-stage kidney disease (ESKD) in >7000 African and Caribbean people with HIV in the UK. Using Poisson regression and East Africans as the reference group, the adjusted incidence rate ratio (95% confidence interval) of ESKD was 3.14 (1.26–7.84) in Southern Africans, 6.35 (2.53–15.96) in West Africans, and 5.26 (1.91–14.43) in Caribbeans. Higher CD4 cell count and suppressed HIV replication were associated with reduced risk of ESKD. The risk of ESKD varied among HIV-positive people of African heritage, with the highest rates observed in those of West African descent.

In vitro anti-HIV-1 activity of the bioactive compound extracted and purified from two different marine macroalgae (seaweeds) (Dictyota bartayesiana J.V.Lamouroux and Turbinaria decurrens Bory)

Highly active antiretroviral therapy (HAART) is the only available remedial measure to treat HIV infected patients, as recognized by the WHO. However, it is associated with toxicity (nephrotoxicity), high cost and most preferably drug resistance in the first-line treatment. Wherefore, potential and novel natural source is the only option for the modern world to challenge this global issue. In recent years, sulfated polysaccharide from marine macroalgae shown to be biologically active as anti-inflammatory, anticoagulant, antitumor, immunomodulatory and antiviral agents. As a direct inhibitor of HIV including other retroviruses, it is considered as a "new generation antiretroviral drug". In our present study, Fucoidan, a sulfated polysaccharide has been extracted from two different macroalgae Dictyota bartayesiana (DD) and Turbinaria decurrens (TD) based on hot water extraction method and further confirmed by FT-IR and RP-HPLC methods. Both the crude and purified fucoidan samples were evaluated for anti-HIV activity after ion exchange chromatography purification. The maximum inhibitory activity of crude and purified fucoidan samples are 90.5% and 89% in the fucoidan extracts of DD. Whereas, it was 89.7% and 92% in the fucoidan extracts of TD. Simultaneously, the IC50 values were determined and recorded as 1.56 µg/ml and 57.6 ng/ml in both the crude and purified fucoidan extracts of DD respectively. Similarly, for TD, it was 3 µg/ml and 131.7 ng/ml in the fucoidan extracts of TD. Therefore, further extensive research work is the most needful to fill the gaps to develop this sulfated polysaccharide as a potential drug for the treatment of HIV patients.

Prevalence of chronic kidney disease among HIV-1-infected patients receiving a combination antiretroviral therapy

BACKGROUND

Chronic kidney disease (CKD) has become one of the most frequent non-infectious comorbidities in the aging HIV-infected population on long-standing combination antiretroviral therapy (cART).

METHODS

We conducted a retrospective, cross-sectional study including HIV-infected adult patients attending our HIV outpatient clinic during the years 2017 and 2018 to assess prevalence and associated risk factors of CKD. Estimated glomerular filtration rate (eGFR) was measured by Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation. CKD was diagnosed and classified according to the National Kidney Foundation guidelines. Logistic regression was employed to identify factors associated with CKD.

RESULTS

We enrolled 2339 HIV-infected patients (91% were Caucasian) with a mean age of 45.3 years and a mean current CD4 lymphocyte count of 531 cells/mm³. CKD was diagnosed in 311 subjects (13.3%). Overall, 294 (12.6%) patients had albuminuria, 108 (4.6%) had eGFR < 60 mL/min/1.73 m², and 78 (3.3%) had albuminuria plus eGFR < 60 mL/min/1.73 m². Stages 4-5 of CKD were documented in 23 (1%) cases. Age greater than 50 years, male gender, hypertension, diabetes mellitus, high triglycerides, nadir CD4 cell count < 200 cells/mm³, current use of tenofovir disoproxyl fumarate (TDF) and of TDF plus a ritonavir-boosted protease inhibitors were independently associated with CKD, while current use of abacavir plus one integrase inhibitor was associated with a reduced risk of CKD.

CONCLUSION

There is a significant prevalence of CKD among HIV-infected persons in association with both traditional and HIV-specific risk factors, requiring a careful periodic monitoring of renal function in these patients.

Renal safety of tenofovir alafenamide vs. tenofovir disoproxil fumarate: a pooled analysis of 26 clinical trials

Supplemental Digital Content is available in the text

Objective:

Compared with tenofovir disoproxil fumarate (TDF), tenofovir alafenamide (TAF) has been associated with improvement in markers of renal dysfunction in individual randomized trials; however, the comparative incidence of clinically significant renal events remains unclear.

Design:

We used a pooled data approach to increase the person-years of drug exposure analysed, maximizing our ability to detect differences in clinically significant outcomes.

Methods:

We pooled clinical renal safety data across 26 treatment-naive and antiretroviral switch studies to compare the incidence of proximal renal tubulopathy and discontinuation due to renal adverse events between participants taking TAF-containing regimens vs. those taking TDF-containing regimens. We performed secondary analyses from seven large randomized studies (two treatment-naive and five switch studies) to compare incidence of renal adverse events, treatment-emergent proteinuria, changes in serum creatinine, creatinine clearance, and urinary biomarkers (albumin, beta-2-microglobulin, and retinol binding protein-to-creatinine ratios).

Results:

Our integrated analysis included 9322 adults and children with HIV (n = 6360 TAF, n = 2962 TDF) with exposure of 12 519 person-years to TAF and 5947 to TDF. There were no cases of proximal renal tubulopathy in participants receiving TAF vs. 10 cases in those receiving TDF (P < 0.001), and fewer individuals on TAF (3/6360) vs. TDF (14/2962) (P < 0.001) discontinued due to a renal adverse event. Participants initiating TAF-based vs. TDF-based regimens had more favourable changes in renal biomarkers through 96 weeks of therapy.

Conclusion:

These pooled data from 26 studies, with over 12 500 person-years of follow-up in children and adults, support the comparative renal safety of TAF over TDF.

Kidney disease in Africans with HIV and tuberculosis

OBJECTIVE

To describe the spectrum of kidney disease in African patients with HIV and tuberculosis (TB).

METHODS

We used data from three cohorts: consecutive patients with HIV/TB in South London (UK, 2004-2016; n = 95), consecutive patients with HIV/TB who underwent kidney biopsy in Cape Town (South Africa, 2014-2017; n = 70), and consecutive patients found to have HIV/TB on autopsy in Abidjan (Cote d'Ivoire, 1991; n = 100). Acute kidney injury (AKI) was ascertained using the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. In the Cape Town cohort, predictors of recovery of kidney function at 6 months were assessed using Cox regression.

RESULTS

In the London cohort, the incidence of moderate/severe AKI at 12 months was 15.1 (95% CI 8.6-26.5) per 100 person-years, and the prevalence of chronic and end-stage kidney disease (ESKD) 13.7 and 5.7%, respectively. HIV-associated nephropathy (HIVAN) was diagnosed in 6% of patients in London, and in 6% of autopsy cases in Abidjan. Evidence of renal TB was present in 60% of autopsies in Abidjan and 61% of kidney biopsies in Cape Town. HIVAN and acute tubular necrosis (ATN) were also common biopsy findings in Cape Town. In Cape Town, 40 patients were dialyzed, of whom 28 (70%) were able to successfully discontinue renal replacement therapy. Antiretroviral therapy status, CD4 cell count, estimated glomerular filtration rate (eGFR) at biopsy and renal histology, other than ATN, were not predictive of eGFR recovery.

CONCLUSION

Kidney disease was common in Africans with HIV/TB. Monitoring of kidney function, and provision of acute dialysis to those with severe kidney failure, is warranted.

Continued Interest and Controversy: Vitamin D in HIV

PURPOSE OF REVIEW

Vitamin D (VitD) deficiency is highly prevalent among HIV-infected individuals. Given the overlapping risk for several chronic disease and immunomodulatory outcomes from both long-standing HIV and VitD deficiency, there is great interest in clarifying the clinical role of VitD for this population.

RECENT FINDINGS

Recent studies have expanded our knowledge regarding the epidemiology and mechanisms of VitD deficiency-associated outcomes in the setting of HIV. Clinical trials focusing on VitD supplementation have demonstrated a positive impact on bone mineral density in subgroups of HIV-infected individuals initiating ART or on suppressive ART regimens; however, significant heterogeneity exists between studies and data are less consistent with other clinical outcomes. Further research is needed to clarify uncertainly in several domains, including identifying patients at greatest risk for poor outcomes from VitD deficiency, standardizing definitions and measurement techniques, and better quantifying the benefits and risks of VitD supplementation across different demographic strata for skeletal and extra-skeletal outcomes.

Pre-exposure Prophylaxis With Tenofovir Disoproxil Fumarate/Emtricitabine and Kidney Tubular Dysfunction in HIV-Uninfected Individuals

BACKGROUND

Pre-exposure prophylaxis (PrEP) with tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) is becoming increasingly adopted for HIV prevention. Tenofovir can cause proximal tubular damage and chronic kidney disease in HIV-infected persons, but little is known regarding its nephrotoxic potential among HIV-uninfected persons. In this study, we evaluated the effects of PrEP on urine levels of the following: α1-microglobulin (α1m), a marker of impaired tubular reabsorption; albuminuria, a measure of glomerular injury; and total proteinuria.

SETTING

The Iniciativa Profilaxis Pre-Exposicion (iPrEx) study randomized HIV-seronegative men and transgender women who have sex with men to oral TDF/FTC or placebo. The iPrEx open-label extension (iPrEx-OLE) study enrolled former PrEP trial participants to receive open-label TDF/FTC.

METHODS

A cross-sectional analysis compared urine biomarker levels by study arm in iPrEx (N = 100 treatment arm, N = 100 placebo arm). Then, urine biomarker levels were compared before and after PrEP initiation in 109 participants of iPrEx-OLE.

RESULTS

In iPrEx, there were no significant differences in urine α1m, albuminuria, or proteinuria by treatment arm. In iPrEx-OLE, after 24 weeks on PrEP, urine α1m and proteinuria increased by 21% [95% confidence interval (CI): 10 to 33] and 18% (95% CI: 8 to 28), respectively. The prevalence of detectable α1m increased from 44% to 65% (P < 0.001) and estimated glomerular filtration rate declined by 4 mL/min/1.73 m (P < 0.001). There was no significant change in albuminuria (6%; 95% CI: -7% to 20%).

CONCLUSION

PrEP with TDF/FTC was associated with a statistically significant rise in urine α1m and proteinuria after 6 months, suggesting that PrEP may result in subclinical tubule dysfunction.

The Changing Face of Human Immunodeficiency Virus-Mediated Kidney Disease

In nearly 40 years since human immunodeficiency virus (HIV) first emerged, much has changed. Our understanding of the pathogenesis of HIV infection and its effect on the cells within each kidney compartment has progressed, and the natural history of the disease has been transformed. What was once an acutely fatal illness is now a chronic disease managed with oral medications. This change is largely due to the advent of antiretroviral drugs, which have dramatically altered the prognosis and progression of HIV infection. However, the success of antiretroviral therapy has brought with it new challenges for the nephrologist caring for patients with HIV/acquired immune deficiency syndrome, including antiretroviral therapy-induced nephrotoxicity, development of non-HIV chronic kidney disease, and rising incidence of immune-mediated kidney injury. In this review, we discuss the pathogenesis of HIV infection and how it causes pathologic changes in the kidney, review the nephrotoxic effects of select antiretroviral medications, and touch upon other causes of kidney injury in HIV cases, including mechanisms of acute kidney injury, HIV-related immune complex glomerular disease, and thrombotic microangiopathy.

Cellular senescence is associated with reorganization of the microtubule cytoskeleton

Senescent cells undergo structural and functional changes that affect essentially every aspect of cell physiology. To date, the impact of senescence on the cytoskeleton is poorly understood. This study evaluated the cytoskeleton in two independent cellular models of kidney epithelium senescence. Our work identified multiple senescence-related alterations that impact microtubules and filamentous actin during interphase. Both filamentous systems reorganized profoundly when cells became senescent. As such, microtubule stability increased during senescence, making these filaments more resistant to disassembly in the cold or by nocodazole. Microtubule stabilization was accompanied by enhanced α-tubulin acetylation on lysine 40 and the depletion of HDAC6, the major deacetylase for α-tubulin lysine 40. Rho-associated kinase Rock1 is an upstream regulator that modulates key properties of the cytoplasmic cytoskeleton. Our research shows that Rock1 concentrations were reduced significantly in senescent cells, and we revealed a mechanistic link between microtubule stabilization and Rock1 depletion. Thus, Rock1 overexpression partially restored the cold sensitivity of microtubules in cells undergoing senescence. Additional components relevant to microtubules were affected by senescence. Specifically, we uncovered the senescence-related loss of the microtubule nucleating protein γ-tubulin and aberrant formation of γ-tubulin foci. Concomitant with the alterations of microtubule and actin filaments, senescent cells displayed functional changes. In particular, cell migration was impaired significantly in senescent cells. Taken together, our study identified new senescence-associated deficiencies of the microtubule and actin cytoskeleton, provided insights into the underlying molecular mechanisms and demonstrated functional consequences that are important to the physiology and function of renal epithelial cells.

Changes in renal function with long-term exposure to antiretroviral therapy in HIV-infected adults in Asia

PURPOSE

Renal disease is common among people living with human immunodeficiency virus (HIV). However, there is limited information on the incidence and risk factors associated with renal dysfunction among this population in Asia.

METHODS

We used data from the TREAT Asia HIV Observational Database. Patients were included if they started antiretroviral therapy during or after 2003, had a serum creatinine measurement at antiretroviral therapy initiation (baseline), and had at least 2 follow-up creatinine measurements taken ≥3 months apart. Patients with a baseline estimated glomerular filtration rate (eGFR) ≤60 mL/min/1.73 m2 were excluded. Chronic kidney disease was defined as 2 consecutive eGFR values ≤60 mL/min/1.73 m2 taken ≥3 months apart. Generalized estimating equations were used to identify factors associated with eGFR change. Competing risk regression adjusted for study site, age and sex, and cumulative incidence plots were used to evaluate factors associated with chronic kidney disease (CKD).

RESULTS

Of 2547 patients eligible for this analysis, tenofovir was being used by 703 (27.6%) at baseline. Tenofovir use, high baseline eGFR, advanced HIV disease stage, and low nadir CD4 were associated with a decrease in eGFR during follow-up. Chronic kidney disease occurred at a rate of 3.4 per 1000 patient/years. Factors associated with CKD were tenofovir use, old age, low baseline eGFR, low nadir CD4, and protease inhibitor use.

CONCLUSIONS

There is an urgent need to enhance renal monitoring and management capacity among at-risk groups in Asia and improve access to less nephrotoxic antiretrovirals.

Renal health after long-term exposure to tenofovir disoproxil fumarate (TDF) in HIV/HBV positive adults in Ghana

OBJECTIVES

The study assessed markers of renal health in HIV/HBV co-infected patients receiving TDF-containing antiretroviral therapy in Ghana.

METHODS

Urinary protein-to-creatinine ratio (uPCR) and albumin-to-protein ratio (uAPR) were measured cross-sectionally after a median of four years of TDF. At this time, alongside extensive laboratory testing, patients underwent evaluation of liver stiffness and blood pressure. The estimated glomerular filtration rate (eGFR) was measured longitudinally before and during TDF therapy.

RESULTS

Among 101 participants (66% women, median age 44 years, median CD4 count 572 cells/mm³) 21% and 17% had detectable HIV-1 RNA and HBV DNA, respectively. Overall 35% showed hypertension, 6% diabetes, 7% liver stiffness indicative of cirrhosis, and 18% urinary excretion of Schistosoma antigen. Tubular proteinuria occurred in 16% of patients and was independently predicted by female gender and hypertension. The eGFR declined by median 1.8 ml/min/year during TDF exposure (IQR -4.4, -0.0); more pronounced declines (≥ 5 ml/min/year) occurred in 22% of patients and were associated with receiving ritonavir-boosted lopinavir rather than efavirenz. HBV DNA, HBeAg, transaminases, and liver stiffness were not predictive of renal function abnormalities.

CONCLUSIONS

The findings mandate improved diagnosis and management of hypertension and suggest targeted laboratory monitoring of patients receiving TDF alongside a booster in sub-Saharan Africa.

Prevalence and Evolution of Renal Impairment in People Living With HIV in Rural Tanzania

Background

We assessed the prevalence, incidence, and predictors of renal impairment among people living with HIV (PLWHIV) in rural Tanzania.

Methods

In a cohort of PLWHIV aged ≥15 years enrolled from January 2013 to June 2016, we assessed the association between renal impairment (estimated glomerural filtration rate < 90 mL/min/1.73 m²) at enrollment and during follow-up with demographic and clinical characteristcis using logistic regression and Cox proportional hazards models.

Results

Of 1093 PLWHIV, 172 (15.7%) had renal impairment at enrollment. Of 921 patients with normal renal function at baseline, 117 (12.7%) developed renal impairment during a median follow-up (interquartile range) of 6.2 (0.4–14.7) months. The incidence of renal impairment was 110 cases per 1000 person-years (95% confidence interval [CI], 92–132). At enrollment, logistic regression identified older age (adjusted odds ratio [aOR], 1.79; 95% CI, 1.52–2.11), hypertension (aOR, 1.84; 95% CI, 1.08–3.15), CD4 count <200 cells/mm³ (aOR, 1.80; 95% CI, 1.23–2.65), and World Health Organization (WHO) stage III/IV (aOR, 3.00; 95% CI, 1.96–4.58) as risk factors for renal impairment. Cox regression model confirmed older age (adjusted hazard ratio [aHR], 1.85; 95% CI, 1.56–2.20) and CD4 count <200 cells/mm³ (aHR, 2.05; 95% CI, 1.36–3.09) to be associated with the development of renal impairment.

Conclusions

Our study found a low prevalence of renal impairment among PLWHIV despite high usage of tenofovir and its association with age, hypertension, low CD4 count, and advanced WHO stage. These important and reassuring safety data stress the significance of noncommunicable disease surveillance in aging HIV populations in sub-Saharan Africa.

Kidney disease in the setting of HIV infection: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

HIV-positive individuals are at increased risk for kidney disease, including HIV-associated nephropathy, noncollapsing focal segmental glomerulosclerosis, immune-complex kidney disease, and comorbid kidney disease, as well as kidney injury resulting from prolonged exposure to antiretroviral therapy or from opportunistic infections. Clinical guidelines for kidney disease prevention and treatment in HIV-positive individuals are largely extrapolated from studies in the general population, and do not fully incorporate existing knowledge of the unique HIV-related pathways and genetic factors that contribute to the risk of kidney disease in this population. We convened an international panel of experts in nephrology, renal pathology, and infectious diseases to define the pathology of kidney disease in the setting of HIV infection; describe the role of genetics in the natural history, diagnosis, and treatment of kidney disease in HIV-positive individuals; characterize the renal risk-benefit of antiretroviral therapy for HIV treatment and prevention; and define best practices for the prevention and management of kidney disease in HIV-positive individuals.

Cumulative exposure of TDF is associated with kidney tubulopathy whether it is currently used or discontinued

OBJECTIVE

Tenofovir disoproxil fumarate (TDF) increases the risk of kidney tubular dysfunction (KTD). This study was conducted to elucidate whether KTD persists after discontinuation of TDF.

DESIGN

A prospective cross-sectional study which enrolled 941 HIV-1-infected patients.

METHODS

KTD was predefined as the presence of at least two abnormalities among the five tubular markers (fractional excretion of phosphate, fractional excretion of uric acid, β2 microglobulinuria, N-acetyl-β-D-glucosaminidase, nondiabetic glycosuria). Logistic regression model was used to examine the association between KTD and cumulative TDF use, as well as current status of TDF use.

RESULTS

In total, 94% of study patients were men (median age 45, estimated glomerular filtration rate 75 ml/min per 1.73 m, CD4 575 cells/μl. About 98% were on antiretroviral therapy. In total, 64% of the patients ever used TDF and 39% currently used TDF. Twenty-nine percent used TDF for more than 5 years. KTD was diagnosed in 116 (12%) patients. In multivariate model, more than 5 years of TDF exposure and current TDF use [odds ratio (OR) 4.2, 95% confidence interval (CI) 2.37-7.56], more than 5 years and past TDF use (OR 2.4, 95% CI 1.09-5.33), less than 5 years and current TDF (OR 2.4, 95% CI 1.24-4.85), and less than 5 years and past TDF (OR 2.4, 95% CI 1.22-4.64) were all significantly associated with KTD, with never TDF use as reference. The results were the same using 4 and 3 years of exposure as the cutoff. However, with 2 years exposure, both less than 2 years and current TDF (OR 2.3, 95% CI 0.84-6.20) and less than 2 years and past TDF (OR 1.9, 95% CI 0.73-4.93) were not associated with KTD, whereas both more than 2 years and current TDF and more than 2 years and past TDF were associated.

CONCLUSION

The association between cumulative TDF use and KTD was strong and robust. The results of the study suggested that TDF-related KTD might persist after discontinuation of TDF if patients used TDF for more than 2 years.

Kidney Disease in HIV: Moving beyond HIV-Associated Nephropathy

In developed countries, remarkable advances in antiretroviral therapy have transformed HIV infection into a chronic condition. As a result, HIV-associated nephropathy, the classic HIV-driven kidney lesion among individuals of African descent, has largely disappeared in these regions. However, HIV-positive blacks continue to have much higher rates of ESRD than HIV-positive whites, which could be attributed to the APOL1 renal risk variants. Additionally, HIV-positive individuals face adverse consequences beyond HIV itself, including traditional risk factors for CKD and nephrotoxic effects of antiretroviral therapy. Concerns for nephrotoxicity also extend to HIV-negative individuals using tenofovir disoproxil fumarate-based pre-exposure prophylaxis for the prevention of HIV infection. Therefore, CKD remains an important comorbid condition in the HIV-positive population and an emerging concern among HIV-negative persons receiving pre-exposure prophylaxis. With the improved longevity of HIV-positive individuals, a kidney transplant has become a viable option for many who have progressed to ESRD. Herein, we review the growing knowledge regarding the APOL1 renal risk variants in the context of HIV infection, antiretroviral therapy-related nephrotoxicity, and developments in kidney transplantation among HIV-positive individuals.

Higher Prevalence and Faster Progression of Chronic Kidney Disease in Human Immunodeficiency Virus-Infected Middle-Aged Individuals Compared With Human Immunodeficiency Virus-Uninfected Controls

Background

Human immunodeficiency virus (HIV)-infected individuals are at increased risk of chronic kidney disease (CKD). Human immunodeficiency virus infection, traditional CKD risk factors, and combination antiretroviral therapy (cART) may all contribute.

Methods

We compared prevalence of renal impairment (estimated glomerular filtration rate [eGFR] <60 mL/min/1.73m2), albuminuria (albumin/creatinine ratio ≥3 mg/mmol), and proximal renal tubular dysfunction (retinol-binding protein/creatinine ratio >2.93μg/mmol and/or fractional phosphate excretion >20% with plasma phosphate <0.8 mmol/L) in 596 HIV-infected and 544 HIV-uninfected AGEhIV Cohort Study participants. We also assessed whether being HIV-infected on cART, with follow-up censored when cART regimen was modified, was associated with greater eGFR decline or worsening albuminuria (increase ≥10%/year with change in albuminuria category).

Results

Human immunodeficiency virus infection was independently associated with renal impairment (adjusted odds ratio [aOR] = 2.1; 95% confidence interval [CI] = 1.0-4.4), albuminuria (aOR = 5.8; 95% CI = 3.7-9.0), and proximal renal tubular dysfunction (aOR = 7.0; 95% CI = 4.9-10.2]). Among 377 HIV-infected and 479 HIV-uninfected individuals (median follow-up = 3.9/4.1 years, respectively) included in longitudinal analyses, being HIV-infected and remaining on unmodified cART was independently associated with greater eGFR decline (-0.56; 95% CI = -0.87 to -0.24 mL/min/1.73m2/year) and worsening albuminuria (aOR = 2.3; 95% CI = 1.3-4.0).

Conclusions

In these middle-aged individuals, HIV infection was independently associated with renal impairment, albuminuria, and proximal renal tubular dysfunction. Human immunodeficiency virus-infected individuals on cART (predominantly containing tenofovir disoproxil fumarate) were also more likely to experience eGFR decline and worsening albuminuria compared with HIV-uninfected individuals.

Incidence of renal Fanconi syndrome in patients taking antiretroviral therapy including tenofovir disoproxil fumarate

The objective of this study was to determine the incidence and predictors of Fanconi Syndrome (FS) in a cohort of patients taking tenofovir disoproxil fumarate (TDF). Clinical records and laboratory investigations from patients receiving TDF between 2002 and 2016 were extracted. FS was defined as normoglycaemic glycosuria and proteinuria and at least one other marker of renal dysfunction. Regression analysis was performed with time to development of FS and the following covariates: ritonavir co-administration, age, gender, co-morbidities (hypertension, hyperlipidaemia, diabetes, viral hepatitis), CD4 cell count nadir and baseline eGFR. One thousand and forty-four patients received TDF without ritonavir and 398 patients with ritonavir. Thirteen cases of FS were identified with a mean duration of exposure of 55 months. The incidence of FS was 1.09/1000PY (0.54-1.63) of TDF exposure (without ritonavir) and 5.50/1000PY (3.66-7.33) of TDF-ritonavir co-administration (p=0.0057). The adjusted hazards ratio for ritonavir co-administration was 4.71 (1.37-16.14, p=0.014). Known risk factors for chronic kidney disease were not associated with development of FS. Ritonavir co-administration, but not other factors, is associated with a greater risk of FS. FS developed late. Known risk factors for chronic kidney disease and length of treatment are not useful for identifying patients most at risk of developing FS in patients taking TDF.