APOL1 Renal Risk Variants and Kidney Function in HIV-1–Infected People From Sub-Saharan Africa

A GWAS of angiotensin-converting enzyme inhibitor-induced angioedema in a South African population

Background

Angiotensin-converting enzyme inhibitor-induced angioedema (AE-ACEI) is a life-threatening adverse event; globally, it is the most common cause of emergency presentations with angioedema. Several genome-wide association studies (GWASs) have found genomic associations with AE-ACEI. However, despite African Americans having a 5-fold increased risk of AE-ACEI, there are no published GWASs from Africa.

Objective

The aim of this study was to conduct a GWAS of AE-ACEI in a South African population and perform a meta-analysis with an African American and European American population.

Methods

The GWAS included 202 South African adults with a history of AE-ACEI and 513 controls without angioedema following angiotensin-converting enzyme inhibitor (ACEI) treatment for at least 2 years. A meta-analysis was conducted with GWAS summary statistics from an African American and European American cohort (from the Vanderbilt-Marshfield cohort, which consisted of 174 case patients and 489 controls).

Results

No single-nucleotide polymorphisms (SNPs) attained genome-wide significance; however, 26 SNPs in the postimputation standard GWAS of the South African cohort and 73 SNPs in the meta-analysis attained suggestive thresholds (P < 5.0 × 10-06). Some of these SNPs were found to be located close to the genes PRKCQ (protein kinase C theta), RAD51B (RAD51 Paralog B), and RIMS1 (regulating synaptic membrane exocytosis 1), which were previously linked with drug-induced angioedema, and also close to the CSMD1 (CUB and sushi multiple domains 1) gene, which has been linked to ACEI cough, providing replication at the gene level but with novel lead SNPs. The study also replicated SNP rs500766 on chromosome 10, which was previously found to be associated with AE-ACEI.

Conclusions

Our results highlight the importance of African populations for detection of novel variants in replication studies. Further increased sampling across the continent and matched functional work are needed to confirm the importance of genetic variation in understanding the biology of AE-ACEI.

An Update on Viral Infection-Associated Collapsing Glomerulopathy

The COVID-19 era has been a reminder to clinicians around the world of the important role that viral infections play in promoting glomerular disease. Several viral infections including human immunodeficiency virus (HIV), severe acute respiratory syndrome coronavirus 2, Epstein-Barr virus, cytomegalovirus, and parvovirus B19 can cause podocyte injury and present with a collapsing glomerulopathy (CG) variant of focal segmental glomerulosclerosis or minimal change disease. CG associated with COVID-19 has been termed COVID-19-associated nephropathy due to its striking resemblance to HIV-associated nephropathy. Host susceptibility is a major determinant of viral infection-associated CG, and the presence of two APOL1 risk variants explains most of the racial predilection to viral-associated CG observed in individuals of African ancestry. Interactions between APOL1 risk variants, viral genes, and the systemic inflammatory response to viral infection all contribute to kidney injury. This review will summarize our current knowledge of viral infection-associated CG, focusing primarily on the clinical presentation, histological features, mechanisms, and disease course of HIV-associated nephropathy and COVID-19-associated nephropathy.

The 14th International Podocyte Conference 2023: from podocyte biology to glomerular medicine

The 14th International Podocyte Conference took place in Philadelphia, Pennsylvania, USA from May 23 to 26, 2023. It commenced with an early-career researchers' meeting on May 23, providing young scientists with a platform to present and discuss their research findings. Throughout the main conference, 29 speakers across 9 sessions shared their insights on podocyte biology, glomerular medicine, novel technologic advancements, and translational approaches. Additionally, the event featured 3 keynote lectures addressing engineered chimeric antigen receptor T cell- and mRNA-based therapies and the use of biobanks for enhanced disease comprehension. Furthermore, 4 brief oral abstract sessions allowed scientists to present their findings to a broad audience. The program also included a panel discussion addressing the challenges of conducting human research within the American Black community. Remarkably, after a 5-year hiatus from in-person conferences, the 14th International Podocyte Conference successfully convened scientists from around the globe, fostering the presentation and discussion of crucial research findings, as summarized in this review. Furthermore, to ensure continuous and sustainable education, research, translation, and trial medicine related to podocyte and glomerular diseases for the benefit of patients, the International Society of Glomerular Disease was officially launched during the conference.

Hypertension Related Co-Morbidities and Complications in Women of Sub-Saharan Africa: A Brief Review

Hypertension is the leading cause of cardiovascular disease in women, and sub-Saharan African (SSA) countries have some of the highest rates of hypertension in the world. Expanding knowledge of causes, management, and awareness of hypertension and its co-morbidities worldwide is an effective strategy to mitigate its harms, decrease morbidities and mortality, and improve individual quality of life. Hypertensive disorders of pregnancy (HDPs) are a particularly important subset of hypertension, as pregnancy is a major stress test of the cardiovascular system and can be the first instance in which cardiovascular disease is clinically apparent. In SSA, women experience a higher incidence of HDP compared with other African regions. However, the region has yet to adopt treatment and preventative strategies for HDP. This delay stems from insufficient awareness, lack of clinical screening for hypertension, and lack of prevention programs. In this brief literature review, we will address the long-term consequences of hypertension and HDP in women. We evaluate the effects of uncontrolled hypertension in SSA by including research on heart disease, stroke, kidney disease, peripheral arterial disease, and HDP. Limitations exist in the number of studies from SSA; therefore, we will use data from countries across the globe, comparing and contrasting approaches in similar and dissimilar populations. Our review highlights an urgent need to prioritize public health, clinical, and bench research to discover cost-effective preventative and treatment strategies that will improve the lives of women living with hypertension in SSA.

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.

Host factors predisposing to kidney disease in people with HIV

PURPOSE OF REVIEW

To highlight advances in understanding of host factors, in particular host genetics, in the development of chronic kidney disease (CKD) in people with HIV.

RECENT FINDINGS

In Black populations, the G1 and G2 variants of the apolipoprotein L1 (APOL1) gene predispose to HIV-associated nephropathy (HIVAN). The risk of HIVAN is mostly confined to individuals with two APOL1 variants (kidney-risk genotypes). APOL1 kidney-risk genotypes are present in approximately 80% of patients with HIVAN and account for nearly half the burden of end-stage CKD in people of African ancestry with HIV. Progress has been made in elucidating the mechanisms of kidney injury in APOL1 nephropathy, and several targeted molecular therapies are being investigated in clinical trials. Genome- and epigenome-wide association studies are identifying additional genes and pathways that may be involved in the pathogenesis of CKD in people with HIV.

SUMMARY

Genetic variants of APOL1 are strongly associated with severe CKD and contribute to the high rates of CKD in Black populations with HIV. Most individuals with APOL1 kidney-risk genotypes, however, do not develop kidney disease and further studies are required to understand the role of additional genetic and environmental factors that may affect CKD risk in this population.

Apolipoprotein L1 gene variants and kidney disease in patients with HIV: a systematic review and meta-analysis

BACKGROUND

The risk of various types of kidney disease is significantly increased in the presence of APOL1 high-risk genotype (carriage of two risk alleles), particularly HIV-associated nephropathy (HIVAN). However, there are discrepancies in the existing evidence about the level of association between APOL1 high-risk genotype and the risk of kidney diseases in people living with HIV (PLWHIV).

METHODS

This systematic review and meta-analysis was conducted to assess the relationship between the APOL1 genotypes and kidney disease in the HIV population. An a priori protocol registered on PROSPERO (ID: CRD42021253877), was followed by a systematic search of five electronic databases. Database-specific search terms were used to identify observational studies that evaluated the outcomes chosen in the review, based on a set of prespecified eligibility criteria. Using a random effect model, the odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were pooled for the meta-analysis.

RESULTS

After screening 4418 citations, 14 articles comprising 11,069 participants were included in this review. The risk of chronic kidney disease (CKD) in the HIV positive population was significantly increased in the presence of two APOL1 risk alleles (OR 4.65 [95% CI 3.51-6.15]). Also, a significant association was observed between the carriage of two risk APOL1 variants and proteinuria (OR 2.58 [95% CI 2.05-3.25]), HIVAN (OR 16.67 [95% CI 10.22-27.19]), and progression to end-stage kidney disease (ESKD) hazard ratio: 1.79 (95% CI 1.20-2.66).

CONCLUSION

This review highlights a strong association between the presence of two risk APOL1 variants and an increased risk of kidney disease in PLWHIV, and provides a more precise estimate of the effect size, with smaller 95% CIs for CKD, HIVAN, and progression to ESKD.