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.

Living donor liver transplantation in South Africa: the donor experience

BACKGROUND

Living donor liver transplantation (LDLT) plays a crucial role in liver transplant programmes, particularly in regions with a scarcity of deceased donor organs and especially for paediatric recipients. LDLT is a complex and demanding procedure which places a healthy living donor in harm's way. Donor safety is therefore the overriding concern. This study aimed to report our standardised approach to the evaluation, technical aspects and outcomes of LDLT donor hepatectomy at Wits Donald Gordon Medical Centre.

METHOD

The study population consisted of all patients undergoing LDLT donor hepatectomy since the inception of the programme in March 2013 until 2018. Sixty five living donor hepatectomies were performed. Primary outcome measures included donor demographics, operative time, peak bilirubin, aspartate and alanine transaminase levels postoperatively, length of hospital stay and postoperative complications using the Clavien-Dindo classification.

RESULTS

The majority of the donors were female, most were parents with mothers being the donor almost 85% of the time. The median operative time was 374 minutes with a downward trend over time as experience was gained. The median length of hospital stay was 7 days. There was no mortality and the complication rate was 30% with the majority being minor (Grade 1).

CONCLUSION

Living donor liver transplant from adult-to-child has been successfully initiated in South Africa. Living donor hepatectomy can be safely performed with acceptable outcomes for the donor. Wait-list mortality however remains unacceptably high. Expansion of LDLT as well as real change in deceased donor policy is required to address this issue.

Primary repair of a delayed presentation thoracic oesophageal gunshot injury: A report of two cases

Thoracic oesophageal gunshot injuries are uncommon, and the morbidity and mortality rates are extremely high and depend on the elapsed time, injury severity, and concomitant organ damage. Thus, early diagnosis is paramount to avoid delays, which in turn confer poorer outcomes. Current management strategies are still controversial and depend on the patient's physiologic state. We experienced two cases of thoracic oesophageal gunshot injury, both of whom were treated by primary repair and were successfully discharged. Decision-making strategies should be based on the patient's physiologic reserve, experience of the attending surgical team, and ancillary services available at the facility.

Crossbow injury to the neck

Crossbow injuries are uncommon among penetrating trauma. The tendency for a crossbow bolt to remain in situ appears to limit catastrophic haemorrhage despite the involvement of major vessels.1 Here we report our experience with an injury to the left internal jugular vein by a crossbow bolt. The injury was successfully treated by emergency neck exploration.