African origins and chronic kidney disease susceptibility in the human immunodeficiency virus era

APOL1 Modulates Renin-Angiotensin System

Patients carrying APOL1 risk alleles (G1 and G2) have a higher risk of developing Focal Segmental Glomerulosclerosis (FSGS); we hypothesized that escalated levels of miR193a contribute to kidney injury by activating renin-angiotensin system (RAS) in the APOL1 milieus. Differentiated podocytes (DPDs) stably expressing vector (V/DPD), G0 (G0/DPDs), G1 (G1/DPDs), and G2 (G2/DPDs) were evaluated for renin, Vitamin D receptor (VDR), and podocyte molecular markers (PDMMs, including WT1, Podocalyxin, Nephrin, and Cluster of Differentiation [CD]2 associated protein [AP]). G0/DPDs displayed attenuated renin but an enhanced expression of VDR and Wilms Tumor [WT]1, including other PDMMs; in contrast, G1/DPDs and G2/DPDs exhibited enhanced expression of renin but decreased expression of VDR and WT1, as well as other PDMMs (at both the protein and mRNA levels). G1/DPDs and G2/DPDs also showed increased mRNA expression for Angiotensinogen and Angiotensin II Type 1 (AT1R) and 2 (AT2R) receptors. Protein concentrations of Brain Acid-Soluble Protein [BASP]1, Enhancer of Zeste Homolog [EZH]2, Histone Deacetylase [HDAC]1, and Histone 3 Lysine27 trimethylated [H3K27me3] in WT1-IP (immunoprecipitated proteins with WT1 antibody) fractions were significantly higher in G0/DPDs vs. G1/DPD and G2/DPDs. Moreover, DPD-silenced BASP1 displayed an increased expression of renin. Notably, VDR agonist-treated DPDs showed escalated levels of VDR and a higher expression of PDMMs, but an attenuated expression of renin. Human Embryonic Kidney (HEK) cells transfected with increasing APOL1(G0) plasmid concentrations showed a corresponding reduction in renin mRNA expression. Bioinformatics studies predicted the miR193a target sites in the VDR 3'UTR (untranslated region), and the luciferase assay confirmed the predicted sites. As expected, podocytes transfected with miR193a plasmid displayed a reduced VDR and an enhanced expression of renin. Renal cortical section immunolabeling in miR193a transgenic (Tr) mice showed renin-expressing podocytes. Kidney tissue extracts from miR193aTr mice also showed reduced expression of VDR and PDMMs, but enhanced expression of Renin. Blood Ang II levels were higher in miR193aTr, APOLG1, and APOL1G1/G2 mice when compared to control mice. Based on these findings, miR193a regulates the activation of RAS and podocyte molecular markers through modulation of VDR and WT1 in the APOL1 milieu.

Chronic Kidney Disease in Brazil: Current Status and Recommended Improvements

Background

Over the last 3 decades, over 700 million individuals worldwide have been diagnosed with chronic kidney disease (CKD). In a 2017 survey in southern Brazil, 11.4% of those surveyed had CKD. Early identification and effective therapy in Brazil may reduce CKD's impact. This panel discusses the early diagnosis and treatment of CKD and the barriers and actions needed to improve the management of CKD in Brazil. A panel of Brazilian nephrologists was provided with relevant questions to address before a multiday conference. During this meeting, each narrative was discussed and edited through several rounds until agreement on the relevant topics and recommendations was achieved.

Summary

Panelists highlighted hurdles to early diagnosis and treatment of CKD. These include, but are not limited to, a lack of public and patient education, updated recommendations, multidisciplinary CKD treatment, and a national CKD database. People-centered, physician-centered, and healthcare institution-centered actions can be taken to improve outcomes. Patient empowerment is needed via multiple channels of CKD education and access to health-monitoring wearables and apps. Primary care clinicians and nonspecialists must be trained to screen and manage CKD-causing illnesses, including diabetes and hypertension. The healthcare system may implement a national health data gathering system, more screening tests, automated test result reporting, and telehealth.

Key Messages

Increasing access to early diagnosis can provide a path to improving care for patients with CKD. Concerted efforts from all stakeholders are needed to overcome the barriers.

HIV and Associated TB: A Lethal Association for Kidney Health?

Human immunodeficiency virus (HIV) and tuberculosis (TB) are the leading infectious causes of death globally. The combined brunt of these diseases is experienced mainly in low-income and lower-middle-income countries. HIV/TB have devastating effects on the kidneys, leading to accelerated decline of kidney function as well as mortality. Managing the triad of TB/HIV and kidney disease is challenging. We discuss the epidemiology of HIV/TB coinfection and the kidney and the key mechanisms of kidney disease including genetic susceptibility. The clinical presentation and pathology, as well as the challenges of diagnosing CKD in these patients, also are discussed. The strategies to prevent and manage HIV/TB-related kidney disease such as proper assessment, avoiding nephrotoxic regimens, drug dose adjustments, kidney function monitoring, avoidance of drug-drug interactions, and other interventions are explored. We also briefly discuss the complexities around HIV/TB patients on dialysis and kidney transplantation. HIV/TB coinfection presents an increased risk for kidney-related morbidity and mortality; patients with this triad need to be given special consideration for future research and management.

Leveraging genomic diversity for discovery in an electronic health record linked biobank: the UCLA ATLAS Community Health Initiative

BACKGROUND

Large medical centers in urban areas, like Los Angeles, care for a diverse patient population and offer the potential to study the interplay between genetic ancestry and social determinants of health. Here, we explore the implications of genetic ancestry within the University of California, Los Angeles (UCLA) ATLAS Community Health Initiative-an ancestrally diverse biobank of genomic data linked with de-identified electronic health records (EHRs) of UCLA Health patients (N=36,736).

METHODS

We quantify the extensive continental and subcontinental genetic diversity within the ATLAS data through principal component analysis, identity-by-descent, and genetic admixture. We assess the relationship between genetically inferred ancestry (GIA) and >1500 EHR-derived phenotypes (phecodes). Finally, we demonstrate the utility of genetic data linked with EHR to perform ancestry-specific and multi-ancestry genome and phenome-wide scans across a broad set of disease phenotypes.

RESULTS

We identify 5 continental-scale GIA clusters including European American (EA), African American (AA), Hispanic Latino American (HL), South Asian American (SAA) and East Asian American (EAA) individuals and 7 subcontinental GIA clusters within the EAA GIA corresponding to Chinese American, Vietnamese American, and Japanese American individuals. Although we broadly find that self-identified race/ethnicity (SIRE) is highly correlated with GIA, we still observe marked differences between the two, emphasizing that the populations defined by these two criteria are not analogous. We find a total of 259 significant associations between continental GIA and phecodes even after accounting for individuals' SIRE, demonstrating that for some phenotypes, GIA provides information not already captured by SIRE. GWAS identifies significant associations for liver disease in the 22q13.31 locus across the HL and EAA GIA groups (HL p-value=2.32×10-16, EAA p-value=6.73×10-11). A subsequent PheWAS at the top SNP reveals significant associations with neurologic and neoplastic phenotypes specifically within the HL GIA group.

CONCLUSIONS

Overall, our results explore the interplay between SIRE and GIA within a disease context and underscore the utility of studying the genomes of diverse individuals through biobank-scale genotyping linked with EHR-based phenotyping.

A focus on the association of Apol1 with kidney disease in children

Individuals of African origin have an increased risk of developing various progressive chronic kidney diseases (CKD). This risk has been attributed to genetic variants (G1, G2) in apolipoprotein-L1 (APOL1) gene. In the pediatric population, especially in children affected by sickle cell disease (SCD), by human immunodeficiency virus (HIV), or with various glomerular diseases, APOL1 risk variants have been associated with the development of hypertension, albuminuria, and more rapid decline of kidney function. The present review focuses on existing APOL1-related epidemiological data in children with CKD. It also includes data from studies addressing racial disparities in CKD, the APOL1-related innate immunity, and the relationship between APOL1 and CKD and pathogenic pathways mediating APOL1-related kidney injury.

COVID-19-associated collapsing glomerulopathy: a report of two cases and literature review

Nephrotic range proteinuria has been reported during the course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease (COVID-19). However, the pathological mechanisms underlying this manifestation are unknown. In this article, we present two cases of collapsing glomerulopathy (CG) associated with acute tubular necrosis during the course of COVID-19, and review the literature for similar reports. In our two cases, as in the 14 cases reported so far, the patients were of African ancestry. The 14 patients assessed had an APOL1 high-risk genotype. At the end of the reported period, two patients had died and five patients were still requiring dialysis. The 16 cases detailed in the present report strongly argue in favour of a causal link between SARS-CoV-2 infection and the occurrence of CG in patients homozygous for APOL1 high-risk genotype for which the term COVID-associated nephropathy (COVIDAN) can be put forward.

Prevalence of tubulopathy and association with renal function loss in HIV-infected patients

BACKGROUND

The incidence of chronic kidney disease (CKD) is 10 times higher in human immunodeficiency virus (HIV)-infected patients than in the general population. We explored the prevalence and determinants of proximal tubular dysfunction (PTD) in HIV-infected individuals, and assessed the impact of the tubulopathy on the estimated glomerular filtration rate (eGFR) outcome.

METHODS

A cohort study was performed on 694 outpatients followed in a French centre to analyse the prevalence of PTD, the diagnosis performance of screening tools and the associated factors. eGFR was prospectively evaluated to analyse the predictive value of the tubulopathy on eGFR decrease.

RESULTS

At inclusion, 14% of the patients presented with PTD and 5% with CKD. No individual tubular marker, including non-glomerular proteinuria, glycosuria dipstick or hypophosphataemia, registered sufficient performance to identify PTD. We found a significant interaction between tenofovir disoproxil fumarate exposure and ethnicity (P = 0.03) for tubulopathy risk. Tenofovir disoproxil fumarate exposure was associated with PTD in non-Africans [adjusted odds ratio (aOR) = 4.71, P < 10-3], but not in patients of sub-Saharan African origin (aOR = 1.17, P = 0.73). Among the 601 patients followed during a median of 4.3 years, 13% experienced an accelerated eGFR decline. Unlike microalbuminuria and glomerular proteinuria, tubulopathy was not associated with accelerated eGFR decline.

CONCLUSION

PTD is not rare in HIV-infected individuals but is less frequent in sub-Saharan African patients and is associated with tenofovir disoproxil fumarate exposure only in non-Africans. Its diagnosis requires multiple biochemical testing and it is not associated with an accelerated eGFR decline.

Senses and Meanings of Conservative Treatment in People with Chronic Kidney Disease

Objective: To unveil the senses and meanings of conservative treatment in people with chronic kidney disease (CKD). Materials and Methods: A descriptive and exploratory study with a qualitative approach. It was developed in 2017, with a sample of individuals with CKD undergoing conservative treatment. A semi-structured interview was used and the data were analyzed using simple descriptive statistics and content analysis. Results: 25 individuals participated in the study, of which 56 % were female; 52 % belonged to the 60-79-year-old age group; 48 % were white-skinned; 48 % did not complete elementary school; and only 12 % worked. Content analysis revealed two categories: food restriction: anguishes and impacts that affect the daily lives of patients with CKD and the social imaginary and fear related to renal replacement therapy. Conclusions: The results revealed that diet and fear about dialysis therapy produce uncertainty, anxiety, and insecurity, in addition to a wide and impacting change in people’s lives.

Gene of the month: APOL1

Apolipoprotein L1 (APOL1) is a protein encoded by the APOL1 gene, found only in humans and several primates. Two variants encoding two different isoforms exist for APOL1, namely G1 and G2. These variants confer increased protection against trypanosome infection, and subsequent African sleeping sickness, and also increase the likelihood of renal disease in individuals of African ancestry. APOL1 mutations are associated with increased risk of chronic kidney disease, inflammation, and exacerbation of systemic lupus erythematosus-associated renal dysfunction. This review serves to outline the structure and function of APOL1, as well as its role in several disease outcomes.

The epidemiology of chronic kidney disease (CKD) in rural East Africa: A population-based study

Background

Chronic kidney disease (CKD) may be common among individuals living in sub-Saharan Africa due to the confluence of CKD risk factors and genetic predisposition.

Methods

We ascertained the prevalence of CKD and its risk factors among a sample of 3,686 participants of a population-based HIV trial in rural Uganda and Kenya. Prevalent CKD was defined as a serum creatinine-based estimated glomerular filtration rate <60 mL/min/1.73m² or proteinuria (urine dipstick ≥1+). We used inverse-weighting to estimate the population prevalence of CKD, and multivariable log-link Poisson models to assess the associations of potential risk factors with CKD.

Results

The estimated CKD prevalence was 6.8% (95% CI 5.7–8.1%) overall and varied by region, being 12.5% (10.1–15.4%) in eastern Uganda, 3.9% (2.2–6.8%) in southwestern Uganda and 3.7% (2.7–5.1%) in western Kenya. Risk factors associated with greater CKD prevalence included age ≥60 years (adjusted prevalence ratio [aPR] 3.5 [95% CI 1.9–6.5] compared with age 18–29 years), HIV infection (aPR 1.6 [1.1–2.2]), and residence in eastern Uganda (aPR 3.9 [2.6–5.9]). However, two-thirds of individuals with CKD did not have HIV, diabetes, or hypertension as risk factors. Furthermore, we noted many individuals who did not have proteinuria had dipstick positive leukocyturia or hematuria.

Conclusion

The prevalence of CKD is appreciable in rural East Africa and there are considerable regional differences. Conventional risk factors appear to only explain a minority of cases, and leukocyturia and hematuria were common, highlighting the need for further research into understanding the nature of CKD in sub-Saharan Africa.

APOL1 Risk Genotypes Are Associated With Early Kidney Damage in Children in Sub-Saharan Africa

INTRODUCTION

Apolipoprotein-L1 (APOL1) risk variants G1 and G2 increase the risk of chronic kidney disease (CKD), including HIV-related CKD, among African Americans. However, such data from populations living in Africa, especially children, remain limited. Our research aimed to determine the prevalence of APOL1 risk variants and to assess the association between these variants and early-stage CKD in the general pediatric population and HIV-infected children.

METHODS

In a cross-sectional study, we enrolled 412 children from the general population and 401 HIV-infected children in Kinshasa, Democratic Republic of Congo (DRC). APOL1 high-risk genotype (HRG) was defined by the presence of 2 risk variants (G1/G1, G2/G2, or G1/G2), and low-risk genotype (LRG) by the presence of 0 or 1 risk variants. The main outcome was elevated albuminuria, defined as a urinary albumin/creatinine ratio ≥30 mg/g.

RESULTS

APOL1 sequence analysis revealed that in the general population, 29 of 412 participants (7.0%) carried HRG, 84 of 412 (20.4%) carried the G1/G0 genotype, and 61 of 412 (14.8%) carried the G2/G0 genotype. In HIV-infected children, 23 of 401 (5.7%) carried HRG, and the same trend as in the general population was observed in regard to the prevalence of LRG. Univariate analysis showed that in the general population, 5 of 29 participants (17.2%) carrying HRG had elevated albuminuria, compared with 35 of 383 (9.0%) with LRG (odds ratio [OR] 2.1, 95% confidence interval [CI] 0.6-6.0; P = 0.13). In HIV-infected children, participants who carried APOL1 HRG had almost 22-fold increased odds of albuminuria compared to those with LRG.

CONCLUSION

The APOL1 risk variants are prevalent in children living in DRC. HRG carriers have increased odds of early kidney disease, and infection with HIV dramatically increases this probability.

Chronic kidney disease in patients infected with human immunodeficiency virus (HIV) in an urban cohort

BACKGROUND AND OBJECTIVES

HIV-infected patients are at risk for developing chronic kidney disease (CKD), defined by estimated glomerular filtration rate (eGFR) <60 ml/min/1.73m2. Our purpose was to understand the genesis of CKD in HIV patients from a large urban clinic in Houston, Texas, USA, and to characterize progression of CKD in the cohort.

DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS

A retrospective cohort study (2012-2016) was conducted in all HIV-infected patients seen in a federally qualified community health center in Houston, Texas. CKD prevalence and its association with HIV viral load and CD4 count were determined. The association of the change in eGFR over time and comorbidities was assessed using linear mixed models.

RESULTS

Of 3714 HIV-infected patients analyzed, 153 (4.1%) had CKD. The prevalence of CKD in the different racial groups was 5.4% White, 4.0% African American, 2.8% Hispanic/Latino and 3.2% Asian. There was no difference in the rate of decline in kidney function in White vs. African American HIV infected patients with CKD. Compared with non-CKD patients, CKD patients were older, had lived longer with HIV infection, had lower CD4 cell counts, higher proportions of hypertension, hyperlipidemia, and cerebrovascular disease, and had significantly higher rates of eGFR deterioration represented by a median decrease of 26.5% from first to last follow-up eGFR (versus 0% change). Linear mixed modeling identified older age, male gender, White race, longer time with HIV infection, hypertension, history of kidney stones, cerebrovascular disease, autoimmune disease, increased potassium and total cholesterol levels, and being treated with combination ART as associated with a worsening eGFR over time.

CONCLUSION

This study demonstrates a prevalence of CKD in HIV-infected patients of 4.1% and points to an important role for HIV medications and other common comorbidities in the genesis and progression of kidney disease. Importantly, CKD was not more prevalent in African Americans than in Whites, perhaps due to a low prevalence of IV drug abuse as inferred from the lower prevalence of HCV infection in this cohort.

Serum creatinine and estimated glomerular filtration rates in HIV positive and negative adults in Ethiopia

BACKGROUND

Glomerular filtration rate estimating equations using serum creatinine are not validated in most African settings. We compared serum creatinine and estimated glomerular filtration rate (eGFR) in HIV positive and negative adults and assessed the performance of eGFR equations ((Cockcroft and Gault (CG), Modification of Diet in Renal Disease (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)) compared to 24-hour creatinine clearance in HIV positive adults.

METHODS

Data were collected on demographic, anthropometric, body composition, clinical parameters and serum creatinine in HIV positive and negative adults. 24-hour urine was collected from some of the HIV positive adults who volunteered. Bias was calculated as mean difference between 24-hr creatinine clearance and eGFR (eGFR- 24 hour creatinine clearance) and the accuracy of each eGFR equation was calculated as the percentage of estimates within 30% of creatinine clearance.

RESULTS

A total of 340 HIV positive and 100 HIV negative adults were included in this study. Creatinine clearance was determined for 46 of HIV positive adults. Serum creatinine increased with increasing age, weight, height, body surface area, fat free mass and grip strength in both HIV positive and negative adults (P<0.05). No difference was observed in eGFR between HIV positive and HIV negative adults. For all eGFR equations, the correlation between eGFR and 24-hr creatinine clearance was 0.45-0.53 and the accuracy within 30% of 24-hr creatinine clearance was 24-46%. Removing ethnic coefficient reduced the bias and improved accuracy of the CKD-EPI and the MDRD estimates.

CONCLUSION

Ethiopian HIV positive adults in the present study had good kidney function at the initiation of antiretroviral treatment. However, all eGFR equations overestimated 24-hr creatinine clearance in the study population. Creatinine based eGFR equations that accounts for low muscle mass and body surface area are needed.

Common and Founder Mutations for Monogenic Traits in Sub-Saharan African Populations

This review highlights molecular genetic studies of monogenic traits where common pathogenic mutations occur in black families from sub-Saharan Africa. Examples of founder mutations have been identified for oculocutaneous albinism, cystic fibrosis, Fanconi anemia, and Gaucher disease. Although there are few studies from Africa, some of the mutations traverse populations across the continent, and they are almost all different from the common mutations observed in non-African populations. Myotonic dystrophy is curiously absent among Africans, and nonsyndromic deafness does not arise from mutations in GJB2 and GJB7. Locus heterogeneity is present for Huntington disease, with two common triplet expansion loci in Africa, HTT and JPH3. These findings have important clinical consequences for diagnosis, treatment, and genetic counseling in affected families. We currently have just a glimpse of the molecular etiology of monogenic diseases in sub-Saharan Africa, a proverbial “ears of the hippo” situation.

APOL1 risk variants and kidney disease: what we know so far

There are striking differences in chronic kidney disease between Caucasians and African descendants. It was widely accepted that this occurred due to socioeconomic factors, but recent studies show that apolipoprotein L-1 (APOL1) gene variants are strongly associated with focal segmental glomerulosclerosis, HIV-associated nephropathy, hypertensive nephrosclerosis, and lupus nephritis in the African American population. These variants made their way to South America trough intercontinental slave traffic and conferred an evolutionary advantage to the carries by protecting against forms of trypanosomiasis, but at the expense of an increased risk of kidney disease. The effect of the variants does not seem to be related to their serum concentration, but rather to local action on the podocytes. Risk variants are also important in renal transplantation, since grafts from donors with risk variants present worse survival.

Management of drug-resistant tuberculosis in special sub-populations including those with HIV co-infection, pregnancy, diabetes, organ-specific dysfunction, and in the critically ill

Tuberculosis remains a major problem globally, and is the leading cause of death from an infectious agent. Drug-resistant tuberculosis threatens to marginalise the substantial gains that have recently been made in the fight against tuberculosis. Drug-resistant TB has significant associated morbidity and a high mortality, with only half of all multidrug-resistant TB patients achieving a successful treatment outcome. Patients with drug-resistant TB in resource-poor settings are now gaining access to newer and repurposed anti-tuberculosis drugs such as bedaquiline, delamanid and linezolid. However, with ever increasing rates of co-morbidity, there is little guidance on how to manage complex patients with drug-resistant TB. We address that knowledge gap, and outline principles underpinning the management of drug-resistant TB in special situations including HIV co-infection, pregnancy, renal disease, liver disease, diabetes, and in the critically ill.

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 correlates of chronic kidney disease (CKD) among ART-naive HIV patients in the Niger-Delta region of Nigeria

Widespread use of antiretroviral therapy (ART) in human immunodeficiency virus (HIV) patients has led to improved longevity with the attendant increase in noncommunicable disease prevalence including chronic kidney disease (CKD). This study documents the prevalence of CKD in a large HIV population in Southern Nigeria.This is a single center, 15-year analysis in ART-naïve patients. CKD was defined as the occurrence of estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m on 2 consecutive occasions 3 to 12 months apart using the chronic kidney disease epidemiology collaboration (CKD-EPI) equation. The Cochran-Armitage and Cuzick tests were employed to assess for trend across the years for CKD prevalence and CD4 count, respectively. Multivariable logistic regression models were used to identify independent associations with CKD.In all, 1317 patients (62.2% females) with mean age of 34.5 years and median CD4 count of 194 cells/μL were included. CKD prevalence was 13.4% (95%CI 11.6%-15.4%) using the CKD-EPI equation (without the race factor). Multivariable analysis identified increasing age and CD4 count <200 cells/μL as being independently associated with CKD occurrence.This study reports a high prevalence of CKD in ART-naïve HIV-infected patients. Measures to improve diagnosis of kidney disease and ensure early initiation of treatment should be integrated in HIV treatment programmes in this setting.

HIV-Associated Nephropathy in Africa: Pathology, Clinical Presentation and Strategy for Prevention

The human immunodeficiency virus (HIV) infection can lead to progressive decline in renal function known as HIV-associated nephropathy (HIVAN). Importantly, individuals of African ancestry are more at risk of developing HIVAN than their European descent counterparts. An in-depth search on Google Scholar, Medline and PubMed was conducted using the terms "HIVAN" and "pathology and clinical presentation", in addition to "prevalence and risk factors for HIVAN", with special emphasis on African countries for any articles published between 1990 and 2017. HIVAN is characterized by progressive acute renal failure, proteinuria and enlarged kidneys. A renal biopsy is necessary to establish definitive diagnosis. Risk factors are male gender, low CD4 counts, high viral load and long use of combined antiretroviral medication (cART). There is a wide geographical variation in the prevalence of HIVAN as it ranges from 4.7% to 38% worldwide and little published literature is available about its prevalence in African nations. Microalbuminuria is a common finding in African populations and is significantly associated with severity of HIV disease progression and CD4 count less than 350 cells/µL. Other clinical presentations in African populations include acute kidney injury (AKI), nephrotic syndrome and chronic kidney disease. The main HIV-associated renal pathological lesions were focal segmental glomerulosclerosis, mainly the collapsing form, acute interstitial nephritis (AIN), and immune complex-mediated glomerulonephritis (ICGN). HIV infection-induced transcriptional program in renal tubular epithelial cells as well as genetic factors is incriminated in the pathogenesis of HIVAN. This narrative review discusses the prevalence, presentation, pathogenesis and the management of HIVAN in Africa. In low resource setting countries in Africa, dealing with HIV complications like HIVAN may add more of a burden on the health system (particularly renal units) than HIV medication itself. Therefore, the obvious recommendation is early use of cART in order to decrease risk factors that lead to HIVAN.

The functionality of African-specific variants in the TGFB1 regulatory region and their potential role in HIVAN

BACKGROUND

Transcription of transforming growth factor beta-1 (TGF-β1) is regulated by a polymorphic promoter region containing African-specific single nucleotide polymorphisms (SNPs). Some of these SNPs have higher frequencies among Southern Africans compared to other African populations and their functionality has only been partially studied. Due to the high prevalence of HIV-associated nephropathy (HIVAN) in Africans we hypothesized that functional African TGFB1-promoter SNPs may contribute to HIVAN pathogenesis.

METHODS

The functionality of the TGFB1 -1347 C>T variant and African-specific variants (-1287 G>A, -1154 C>T, -387 C>T and -14 G>A) were examined by measuring reporter gene expression in kidney and fibroblast cell lines co-transfected with TGFB1-promoter constructs and an HIV-Tat expression vector. TGF-β1 immunohistochemical staining was performed on kidney biopsies with HIVAN (n = 18) and compared to control biopsies without HIVAN or tubulointerstitial disease (n = 12) using semi-quantitative and digital image analysis. HIVAN cases were genotyped for TGFB1 -1347 and -387 SNP variants.

RESULTS

TGFB1-promoter haplotypes containing the African -387 T-allele resulted in ~ five-fold repression of TGFB1-promoter activity compared to -387 C haplotypes (p ≤ 0.024). HIV-Tat upregulated TGFB1-promoter activity for haplotypes containing -1347 T and -387 T in transfected renal cells (≈ 1.6-fold; p ≤ 0.030) and fibroblasts (≈ 1.3-fold; p ≤ 0.016). The renal interstitium from HIVAN biopsies, compared to HIV-positive and -negative controls, differed in the semi-quantitative TGF-β1 staining and digital optical density analyses. The TGFB1 -1347 and -387 genotypes in HIVAN cases were similar to population controls.

CONCLUSION

African-specific haplotypes lower TGFB1-promoter activity and expression levels and HIV-Tat upregulates TGFB1 promoter activity irrespective of the haplotype.

Evolution of renal function in African patients initiating second-line antiretroviral treatment: findings from the ANRS 12169 2LADY trial

BACKGROUND

To investigate change in renal function in African patients initiating second-line antiretroviral therapy (ART) including ritonavir-boosted protease inhibitor (PI/r) with or without tenofovir disoproxil fumarate (TDF).

METHODS

HIV-1-positive adults, failing standard first-line ART were randomized to either TDF/emtricitabine (FTC)+LPV/r, abacavir + didanosine +LPV/r or TDF/FTC+ darunavir (DRV)/r and followed for 18 months. Patients with an estimated glomerular filtration rate (eGFR) ≥60 ml/min/1.73 m² at baseline were included in this analysis.

RESULTS

Data from 438 out of 454 randomized patients were analysed. Median age was 38 years and 72% were women. Initiation of PI/r-based second-line regimen induced a marked eGFR decline of -10.5 ml/min/1.73 m² at week 4 in all treatment groups with a greater decrease in TDF/FTC+LPV/r arm (-15.1 ml/min/1.73 m²). At month 18, mean eGFR in the non-TDF containing regimen recovered its baseline level and was significantly greater than eGFR 18-month levels in the TDF-containing regimens that experienced only partial recovery (difference: -10.7; CI -16.8, -4.6; P=0.001 in TDF/FTC+LPV/r and -6.4; CI -12.5, -0.3; P=0.04 in TDF/FTC+DRV/r). At 18 months, prevalence of stage 3 chronic kidney disease was low (<3%) and not associated with treatment. One treatment discontinuation and five TDF dosage reductions for renal toxicities were reported in TDF-containing arms.

CONCLUSIONS

Overall, these results suggest a reasonable renal tolerance of a regimen associating TDF/FTC+PI/r in African patients with eGFR>60 ml/ml/1.73 m² at baseline. They also support the recommendation of reassessing renal function 1 month after initiation of treatment including ritonavir to account for the ritonavir-related artefactual decrease of eGFR and determine the new reference baseline value.

Genetics of Sickle Cell-Associated Cardiovascular Disease: An Expert Review with Lessons Learned in Africa

Sickle cell disease (SCD) vastly impacts the African continent and is associated with cardiovascular diseases. Stroke, kidney disease, and pulmonary hypertension are considered as proxies of severity in SCD with several genomic loci implicated in their heritability. The present expert review examined the current data on epidemiology and genetic risk factors of stroke, pulmonary hypertension, and kidney disease associated with SCD, as indexed in PubMed® and Google Scholar®. Studies collectively show that stroke and kidney disease each affect ∼10% of SCD patients, with pulmonary hypertension displaying a higher prevalence of 30% among adults with SCD. There is some evidence that these epidemiology figures may be an underestimate in SCD patients living in Africa. A modest number of publications have identified genetic factors involved in pathways regulating inflammation, coagulation, cell adhesion, heme degradation, α-globin and γ-globin production, and others, which contribute to the development risk of targeted cardiovascular phenotypes. However, in most cases, these studies have not been validated across populations. There is therefore an urgent need for large-scale genome-wide association, whole-exome and whole-genome studies, and multiomics research on cardiovascular diseases associated with SCD, particularly in Africa, to allow for proportional investment of global research funding on diseases that greatly impact the African continent. Ultimately, this will cultivate socially responsible research investments and identification of at-risk individuals with improved preventive medicine, which should be a cornerstone of global precision medicine.