The African Liver Tissue Biorepository Consortium: Capacitating Population-Appropriate Drug Metabolism, Pharmacokinetics, and Pharmacogenetics Research in Drug Discovery and Development.

Pharmaceutical companies subject all new molecular entities to a series of in vitro metabolic characterizations that guide the selection and/or design of compounds predicted to have favorable pharmacokinetic properties in humans. Current drug metabolism research is based on liver tissue predominantly obtained from people of European origin, with limited access to tissue from people of African origin. Given the interindividual and interpopulation genomic variability in genes encoding drug-metabolizing enzymes, efficacy and safety of some drugs are poorly predicted for African populations. To address this gap, we have established the first comprehensive liver tissue biorepository inclusive of people of African origin. The African Liver Tissue Biorepository Consortium currently includes three institutions in South Africa and one in Zimbabwe, with plans to expand to other African countries. The program has collected 67 liver samples as of July 2023. DNA from the donors was genotyped for 120 variants in 46 pharmacogenes and revealed variants that are uniquely found in African populations, including the low-activity, African-specific CYP2C9*5 and *8 variants relevant to the metabolism of diclofenac. Larger liver tissue samples were used to isolate primary human hepatocytes. Viability of the hepatocytes and microsomal fractions was demonstrated by the activity of selected cytochrome P450s. This resource will be used to ensure the safety and efficacy of existing and new drugs in African populations. This will be done by characterizing compounds for properties such as drug clearance, metabolite and enzyme identification, and drug-drug and drug-gene interactions. SIGNIFICANCE STATEMENT: Standard optimization of the drug metabolism of new molecular entities in the pharmaceutical industry uses subcellular fractions such as microsomes and isolated primary hepatocytes, being done mainly with tissue from donors of European origin. Pharmacogenetics research has shown that variants in genes coding for drug-metabolizing enzymes have interindividual and interpopulation differences. We established an African liver tissue biorepository that will be useful in ensuring drug discovery and development research takes into account drug responses in people of African origin.

Contemporary outcomes of the pediatric kidney transplant program in Johannesburg, South Africa, between 2004 and 2017: Better or not-And which way forward?

BACKGROUND: Outcomes for the pediatric kidney transplant program in Johannesburg (1984-2003) were found to be suboptimal. In this study, we compared (a) early (era 1:1984-2003) to contemporary (era 2:2004-2017) outcomes and (b) compared contemporary outcomes between the public and private sector hospitals in our program. METHODS: We conducted a retrospective record review of all pediatric (<18 years) KA transplants performed in our kidney transplant program at Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) and Wits Donald Gordon Medical Centre (WDGMC) from 2004 to 2017. We collected the following data per site: number of recipients, transplants performed, mean follow-up time, and grafts lost; per recipient: age at time of transplant, sex, self-reported population group; transplant history; donor type; etiology of ESKD; recipient and graft survival. Outcomes for era 1 were based on data published on our kidney transplant program, based at CMJAH. RESULTS: At CMJAH (public sector), there was no improvement in recipient and graft survival over time. In the contemporary analysis, 1-, 5-, and 10-year recipient survival, as % (95% CI) was 93 (84-97); 76 (64-84); 59 (44-70) for CMJAH, and 98 (90-99); 95 (86-99); 82 (54-94) for WDGMC (private sector). Similarly, 1-, 5- and 10-year graft survival was 75 (63-84); 55 (42-66); 36 (24-49) for CMJAH, and 96 (87-99); 84 (73-91); 64 (48-76) at WDGMC. CONCLUSION: Contemporary outcomes for the pediatric kidney transplant program at WDGMC are comparable to outcomes achieved in middle- and high-income settings. However, outcomes at CMJAH are suboptimal, reflecting numerous health system, infrastructural and human resource challenges.

Minding the gap-Providing quality transplant care for South African children with acute liver failure.

Pediatric ALF is rare but life-threatening and may require urgent transplantation. In low and middle-income countries, access to transplantation is limited, deceased organ donation rates are low, and data on outcomes scarce. The Wits Donald Gordon Medical Centre, in Johannesburg, is one of only two centers in South Africa that perform pediatric liver transplant. We describe the etiology, clinical presentation, and outcomes of children undergoing liver transplant for ALF at our center over the past 14 years. We performed a retrospective chart review of all children undergoing liver transplantation for ALF from November 2005 to September 2019. Recipient data included demographics, clinical and biochemical characteristics pretransplant, post-operative complications, and survival. We conducted descriptive data analysis and used the Kaplan-Meier method for survival analysis. We performed 182 primary pediatric liver transplants. Of these, 27 (15%) were for ALF, mostly from acute hepatitis A infection (11/27;41%). Just over half of the grafts were from living donors (15/27;56%), and five grafts (5/27;19%) were ABO-incompatible. The most frequent post-transplant complications were biliary leaks (9/27;33%). There were two cases of hepatic artery thrombosis (2/27;7%), one of whom required re-transplantation. Unadjusted patient and graft survival at one and 3 years were the same, at 81% (95% CI 61%-92%) and 78% (95% CI 57%-89%), respectively. At WDGMC, our outcomes for children who undergo liver transplantation for ALF are excellent. We found workable solutions that effectively addressed our pervasive organ shortages without compromising patient outcomes.

Blood stream infections in children in the first year after liver transplantation at Wits Donald Gordon Medical Centre, South Africa.

Children who undergo liver transplantation and subsequently develop BSI are at risk for adverse outcomes. Research from high-income settings contrasts the dearth of information from transplant centers in low- and middle-income countries, such as South Africa. Therefore, this study from Johannesburg aimed to describe the clinical and demographic profile of children undergoing liver transplantation, and determine the incidence and pattern of BSI and associated risk factors for BSI during the first year after liver transplant. Pediatric liver transplants performed from 2005 to 2014 were reviewed. Descriptive analyses summarized donor, recipient, and post-transplant infection characteristics. Association between BSI and sex, cause of liver failure, age, nutritional status, PELD/MELD score, graft type, biliary complications, and acute rejection was determined by Fisher's exact test; and association with length of stay by Cox proportional hazards regression analysis. Survival estimates were determined by the Kaplan-Meier method. Sixty-five children received one transplant and four had repeat transplants, totaling 69 procedures. Twenty-nine BSI occurred in 19/69 (28%) procedures, mostly due to gram-negative organisms, namely Klebsiella species. Risk for BSI was independently associated with biliary atresia (44% BSI in BA compared to 17% in non-BA transplants; P = .014) and post-operative biliary complications (55% BSI in transplants with biliary complications compared to 15% in those without; P = .0013). One-year recipient and graft survival was 78% (CI 67%-86%) and 77% (CI 65%-85%), respectively. In Johannesburg, incident BSI, mostly from gram-negative bacteria, were associated with biliary atresia and post-operative biliary complications in children undergoing liver transplantation.

Early survival on maintenance dialysis therapy in South Africa: evaluation of a pre-dialysis education programme.

BACKGROUND: Mortality in the first year of maintenance dialysis is higher than in subsequent years and, within this first year, the risk of death is highest in the first 90 days. Some studies have shown that pre-dialysis education reduces early mortality. Limited data have been published from South Africa regarding early mortality after commencement of maintenance dialysis treatment and the effect of pre-dialysis intervention programmes on these outcomes. The aim of this study was to assess the impact of a pre-dialysis intervention programme on 90- and 365-day outcomes and to determine incident mortality in a population of chronic haemo- and peritoneal dialysis patients in South Africa. METHODS: This study used a retrospective cohort of 269 patients who received a pre-dialysis intervention [Healthy Start (HS)] and a matched group of 269 patients who did not receive the intervention. Both groups subsequently commenced maintenance haemo-/peritoneal dialysis with National Renal Care (NRC). A between-group comparative analysis was conducted to determine whether there were any differences in morbidity and mortality at 90 and 365 days of chronic dialysis treatment. Survival curves for the first 365 days of treatment were calculated using the Kaplan-Meier estimation for the entire population and by age group, gender, race, diabetes, dialysis modality and presence of a central venous catheter (CVC) at start of dialysis treatment. RESULTS: There were no significant differences between the HS and non-HS groups at 90 and 365 days when comparing mortality, cause of death, hospital admission rates and length of stay. Data were then pooled and a Kaplan-Meier analysis showed 90- and 365-day survival of 96.7 and 85.6%, respectively. The peak mortality occurred at 150 days of dialysis treatment, but this was not significant. Older age and the presence of a CVC were associated with an increased risk of death in the first year of treatment. CONCLUSION: The HS Programme made no difference to mortality in the first year of chronic dialysis. Early survival for both HS and non-HS groups was excellent when compared to international data. Increasing age and the presence of a CVC at the start of chronic dialysis were the two factors that impacted significantly on 1-year survival.

Coronavirus Host Genomics Study: South Africa (COVIGen-SA).

Host genetic factors are known to modify the susceptibility, severity, and outcomes of COVID-19 and vary across populations. However, continental Africans are yet to be adequately represented in such studies despite the importance of genetic factors in understanding Africa's response to the pandemic. We describe the development of a research resource for coronavirus host genomics studies in South Africa known as COVIGen-SA-a multicollaborator strategic partnership designed to provide harmonised demographic, clinical, and genetic information specific to Black South Africans with COVID-19. Over 2,000 participants have been recruited to date. Preliminary results on 1,354 SARS-CoV-2 positive participants from four participating studies showed that 64.7% were female, 333 had severe disease, and 329 were people living with HIV. Through this resource, we aim to provide insights into host genetic factors relevant to African-ancestry populations, using both genome-wide association testing and targeted sequencing of important genomic loci. This project will promote and enhance partnerships, build skills, and develop resources needed to address the COVID-19 burden and associated risk factors in South African communities.

A new fanged frog in the Limnonectes kuhlii complex (Anura: Dicroglossidae) from northeastern Cambodia.

The Limnonectes kuhlii complex is a group of morphologically similar species of fanged frogs distributed across much of mainland and insular Southeast Asia. Many new species in this complex have been described in recent years, primarily on the basis of mitochondrial DNA divergence corroborated by differences in linear measurements and qualitative characters. Males in this species complex develop enlarged heads at sexual maturity, but the degree of head enlargement varies among mature males, even within the same population. We evaluated the utility of body length (snout-vent length minus head length) in descriptive statistics and in size-adjusting measurements for traditional morphometric analysis, as well as a landmark-based geometric morphometric analysis of male head shape, in Indochinese species of the L. kuhlii complex. The analyses supported quantitative and qualitative morphological distinction of a divergent mitochondrial lineage of the L. kuhlii complex in northeastern Cambodia, and the lineage is described as a new species. Limnonectes fastigatus sp. nov. differs from its closest relatives and from geographically proximate members of the complex by having the combination of elongated, slender odontoids; nuptial pads on the first finger; immaculate belly; significantly different body length-adjusted measurements in both sexes; and a significantly different male head shape. The new species is the only member of the L. kuhlii complex known from Cambodia.

The podocin V260E mutation predicts steroid resistant nephrotic syndrome in black South African children with focal segmental glomerulosclerosis.

In black African children with focal segmental glomerulosclerosis (FSGS) there are high rates of steroid resistance. The aim was to determine genetic associations with apolipoprotein L1 (APOL1) renal risk variants and podocin (NPHS2) variants in 30 unrelated black South African children with FSGS. Three APOL1 variants were genotyped and the exons of the NPHS2 gene sequenced in the cases and controls. APOL1 risk alleles show a modest association with steroid sensitive nephrotic syndrome (SSNS) and steroid resistant nephrotic syndrome (SRNS). The NPHS2 V260E variant was present in SRNS cases (V/V = 5; V/E = 4; E/E = 11), and was absent in SSNS cases. Haplotype analysis suggests a single mutation origin for V260E and it was associated with a decline in kidney function over a 60-month period (p = 0.026). The V260E variant is a good predictor of autosomal recessive SRNS in black South African children and could provide useful information in a clinical setting.

Living donor liver transplant from an HIV-positive mother to her HIV-negative child: opening up new therapeutic options.

OBJECTIVE: Transplant a liver from an HIV-positive mother to her HIV-negative child to save the child's life. DESIGN: A unique case of living donor liver transplantation from an HIV-positive mother to her HIV-negative child in South Africa. Two aspects of this case are ground-breaking. First, it involves living donation by someone who is HIV-positive and second it involves controlled transplant of an organ from an HIV-positive donor into an HIV-negative recipient, with the potential to prevent infection in the recipient. METHODS: Standard surgical procedure for living donor liver transplantation at our centre was followed. HIV-prophylaxis was administered preoperatively. Extensive, ultrasensitive HIV testing, over and above standard diagnostic assays, was undertaken to investigate recipient serostatus and is ongoing. RESULTS: Both mother and child are well, over 1 year posttransplantation. HIV seroconversion in our recipient was detected with serological testing at day 43 posttransplant. However, a decline in HIV antibody titres approaching undetectable levels is now being observed. No plasma, or cell-associated HIV-1 DNA has been detected in the recipient at any time-point since transplant. CONCLUSION: This case potentially opens up a new living liver donor pool which might have clinical relevance in countries where there is a high burden of HIV and a limited number of deceased donor organs or limited access to transplantation. However, our recipient's HIV status is equivocal at present and additional investigation regarding seroconversion events in this unique profile is ongoing.

Favourable outcomes for the first 10 years of kidney and pancreas transplantation at Wits Donald Gordon Medical Centre, Johannesburg, South Africa.

BACKGROUND: It is important for centres participating in transplantation in South Africa (SA) to audit their outcomes. Wits Donald Gordon Medical Centre (WDGMC), Johannesburg, SA, opened a transplant unit in 2004. The first 10 years of kidney and pancreas transplantation were reviewed to determine outcomes in respect of recipient and graft survival. METHODS: A retrospective review was conducted of all kidney-alone and simultaneous kidney-pancreas (SKP) transplants performed at WDGMC from 1 January 2004 to 31 December 2013, with follow-up to 31 December 2014 to ensure at least 1 year of survival data. Information was accessed using the transplant registers and clinical records in the transplant clinic at WDGMC. The Kaplan-Meier method was used to estimate 1-, 5- and 10-year recipient and graft survival rates for primary (first graft) kidney-alone and SKP transplants. RESULTS: The overall 10-year recipient and graft survival rates were 80.4% and 66.8%, respectively, for kidney-alone transplantation. In the kidney-alone group, children tended towards better recipient and graft survival compared with adults, but this was not statistically significant. In adults, recipient survival was significantly better for living than deceased donor type. Recipient and graft survival were significantly lower in black Africans than in the white (largest proportion in the sample) reference group. For SKP transplants, the 10-year recipient survival rate was 84.7%, while kidney and pancreas graft survival rates were 73.1% and 43.2%, respectively. CONCLUSION: Outcomes of the first 10 years of kidney and pancreas transplantation at WDGMC compare favourably with local and international survival data.

Morbidity and mortality of black HIV-positive patients with end-stage kidney disease receiving chronic haemodialysis in South Africa.

INTRODUCTION: There are few published data from South Africa (SA) on the outcomes of black HIV-positive patients receiving chronic haemodialysis. METHODS: This retrospective study compared the incidences of vascular and infectious morbidity and mortality in black HIV-positive patients with those in a group of HIV-negative patients matched for ethnicity, age and gender. All the patients were receiving chronic haemodialysis in the medically insured healthcare sector of SA. RESULTS: The incidence of tuberculosis and hospital admission rates for vascular access-related infections were significantly higher in the HIV-positive group than the HIV-negative group. The HIV-positive group had significantly lower albumin (p<0.05) and haemoglobin levels (p<0.01), but this did not impact on mortality. Survival in both groups was excellent. In the HIV-positive group, viral suppression rates were suboptimal with <50% of patients on antiretroviral therapy completely virally suppressed. CONCLUSION: This study has shown that black HIV-positive patients receiving chronic haemodialysis in a healthcare-funded environment in SA have excellent overall survival in spite of higher hospital admission rates and higher infectious morbidity compared with HIV-negative patients.

Diabetogenic effect of tacrolimus in South African patients undergoing kidney transplantation1.

BACKGROUND: Diabetes mellitus (DM) is a complication of tacrolimus therapy. This prospective study evaluated the prevalence of DM in South African black and white patients receiving tacrolimus after kidney transplantation and factors that could identify patients before transplantation who may be at risk of developing DM. METHODS: Fasting blood samples from 17 patients (11 black, 6 white) were analyzed immediately pretransplantation and at 1 and 3 months posttransplantation for glucose, HbAIC, insulin, C-peptide, free fatty acids, lipids, urea, and creatinine. Insulin resistance (IR) was calculated using the homeostasis model assessment (HOMA) and quantitative insulin sensitivity check index (QUICKI) formulas. RESULTS: Eight patients (47%) became diabetic (six black, two white), and nine patients (five black, four white) remained nondiabetic. Mean glucose concentrations in the diabetic group were significantly higher at 1 month (P=0.03) and 3 months (P=0.01). Mean insulin level was also significantly raised at 3 months (P=0.01) as was HbAIC (P=0.001). C-peptide concentrations did not change significantly in either group. Significant correlations emerged between fasting glucose concentrations at 3 months posttransplantation and initial HOMA (r=0.486; P=0.048) and initial QUICKI (r=-0.582; P=0.014). CONCLUSIONS: Occurrence of DM was high and somewhat greater in black patients. IR was the main mechanism involved, together with inadequate beta-cell compensation. IR pretransplantation predicts the subsequent development of DM.