Do genetic variations in proximal tubule transporters influence tenofovir-induced renal dysfunction? An exploratory study in a Ghanaian population

Chronic kidney disease among people living with HIV on TDF based regimen: A systematic review and meta-analysis

INTRODUCTION

Chronic kidney disease is a major public health concern among people living with human immunodeficiency virus (PLWHIV) who are taking tenofovir disoproxil fumarate-based regimen. Despite the available evidence showing a high prevalence of CKD in this population, comprehensive pooled estimate of CKD among PLWHIV receiving TDF based regimen across the globe is lacking. Hence, the present systematic review aimed to provide a global pooled prevalence estimate of CKD.

METHOD

We conducted a systematic review of literatures published between January 2000 and May 2024. Articles and grey literature were searched from the following databases and search engine: PubMed, EMBASE, Scopus, Web of science, The Cumulative Index to Nursing and Allied Health Literature (CINHAL), and Google Scholar. We included eligible studies that report magnitude of CKD in TDF based regimen. We executed the pooled CKD, subgroup analysis, and funnel plot using random effect model. All statistical analysis including sensitivity analysis were made using Stata 17 software.

RESULTS

Sixty-nine studies with 88299 participants included in this meta-analysis. The pooled prevalence of CKD was 7% (95% CI:6-8). CD4 count less than 200 copies per milliliter, and being female were associated with CKD.

CONCLUSION

We concluded that the magnitude of CKD across the globe is high in people living with HIV who have received TDF based regimen. Early identification of CKD by considering regular renal function monitoring, and risk factors especially low CD4 count, and female gender at birth are essential.

TRIAL REGISTRATION

The protocol has been prospectively registered with PROSPERO ((CRD42020136813).

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.

ABCB1, ABCG2, ABCC1, ABCC2, and ABCC3 drug transporter polymorphisms and their impact on drug bioavailability: what is our current understanding?

INTRODUCTION

Interindividual differences in drug response are a frequent clinical challenge partly due to variation in pharmacokinetics. ATP-binding cassette (ABC) transporters are crucial determinants of drug disposition. They are subject of gene regulation and drug-interaction; however, it is still under debate to which extend genetic variants in these transporters contribute to interindividual variability of a wide range of drugs.

AREAS COVERED

This review discusses the current literature on the impact of genetic variants in ABCB1, ABCG2 as well as ABCC1, ABCC2, and ABCC3 on pharmacokinetics and drug response. The aim was to evaluate if results from recent studies would increase the evidence for potential clinically relevant pharmacogenetic effects.

EXPERT OPINION

Although enormous efforts have been made to investigate effects of ABC transporter genotypes on drug pharmacokinetics and response, the majority of studies showed only weak if any associations. Despite few unique results, studies mostly failed to confirm earlier findings or still remained inconsistent. The impact of genetic variants on drug bioavailability is only minor and other factors regulating the transporter expression and function seem to be more critical. In our opinion, the findings on the so far investigated genetic variants in ABC efflux transporters are not suitable as predictive biomarkers.

Duration of antiretroviral therapy among people living with HIV and incidence of hypertension in Ghana

Understanding the differential rates of incident hypertension among People Living with HIV (PLWH) based of duration of exposure to combination antiretroviral therapy (cART) may provide insights into the pathogenesis of hypertension in this population. Utilizing the dataset of a prospective study conducted at a Ghanaian tertiary medical center, we evaluated factors associated with incident hypertension among PLWH previously naïve to cART before study enrollment (cART newly prescribed group, n = 221) versus PLWH established on cART for at least a year (cART established group, n = 212). New-onset hypertension was diagnosed as clinic BP > 140/90 mmHg on two separate clinic visits over 12-month follow-up. Cox proportional hazards regression models were used to assess factors associated with incident hypertension. Mean age of new versus cART established was 41.1 ± 8.2 versus 45.1 ± 8.6 years (p < .001), with more women in the cART established group (68.3 vs. 82%, p = .0009). There were 105 (24.3%) episodes of incident hypertension over 328 person-years follow-up (PYFU), incidence rate of 320.1 (95% CI: 263.1-385.9)/1000 PYFU, with higher rates in new versus cART established (476.6/1000 PYFU vs. 222.8/1000 PYFU, p = 0.0002). Overall, age by increasing decile (aHR 0.76; 95% CI: 0.59-0.98), log HIV-1 viral load (aHR 1.16; 1.04-1.35), and use of tenofovir (aHR 1.66; 1.04-2.64) were associated with incident hypertension. While CD4 counts, age, BMI, pre-diabetes, and urban/peri-urban residency were independently associated with hypertension in the cART established group; no independent predictors were identified among the cART newly prescribed group. Further studies to explore the potential mechanisms underlying incidence of hypertension in PLWH are warranted.