The current pandemic has markedly shifted the focus of the global research and development ecosystem toward infectious agents such as SARS-CoV-2, the causative agent for COVID-19. A case in point is the chronic liver disease associated with hepatitis B virus (HBV) infection that continues to be a leading cause of severe liver disease and death globally. The burden of HBV infection is highest in the World Health Organization designated western Pacific and Africa regions. Tenofovir disoproxil fumarate (TDF) is a nucleoside analogue used in treatment of HBV infection but carries a potential for kidney toxicity. TDF is not metabolized by the cytochrome P450 enzymes and, therefore, its clearance in the proximal tubule of the renal nephron is controlled mostly by membrane transport proteins. Clinical pharmacogenomics of TDF with a focus on drug transporters, discussed in this perspective article, offers a timely example where resource-limited countries and regions of the world with high prevalence of HBV can strengthen the collective efforts to fight both COVID-19 and liver diseases impacting public health. We argue that precision/personalized medicine is invaluable to guide this line of research inquiry. In all, our experience in Ghana tells us that it is important not to forget the burden of chronic diseases while advancing research on infectious diseases such as COVID-19. For the long game with COVID-19, we need to address the public health burden of infectious agents and chronic diseases in tandem.

BACKGROUND: We report the case of a 93-year-old patient with normal left ventricular function and severe mitral annulus calcification, with mild mitral steno-insufficiency.
METHODS: She had developed creeping drugs-induced renal toxicity that is generally totally overlooked, due mainly to statins, a proton pump inhibitor, and aspirin. The Na and fluid retention, along with hypertension that ensued, although not severe, caused acute heart failure (sub-pulmonary edema) by worsening the mitral insufficiency. This occurred due to a less efficient calcific mitral annulus contraction during systole and an increasing mitral transvalvular gradient, as the transvalvular mitral gradient has an exponential relation to flow. After the suspension of the nephrotoxic drugs and starting intravenous furosemide, she rapidly improved. At 6 months follow-up, she is stable, in an NYHA 1-2 functional class, despite the only partial recovery of the renal function.
CONCLUSIONS: Progressive renal failure can functionally worsen even minimal mitral valvulopathy. Drug-induced nephrotoxicity can always be suspected in case of renal failure of unknown etiology. The suspension of the culprit drugs can improve renal function and dramatically improve the clinical symptoms even in a nonagenarian.

Aristolochic acids are naturally occurring nephrotoxins. This study aims to investigate whether physiologically based kinetic (PBK) model-based reverse dosimetry could convert in vitro concentration-response curves of aristolochic acid I (AAI) to in vivo dose response-curves for nephrotoxicity in rat, mouse and human. To achieve this extrapolation, PBK models were developed for AAI in these different species. Subsequently, concentration-response curves obtained from in vitro cytotoxicity models were translated to in vivo dose-response curves using PBK model-based reverse dosimetry. From the predicted in vivo dose-response curves, points of departure (PODs) for risk assessment could be derived. The PBK models elucidated species differences in the kinetics of AAI with the overall catalytic efficiency for metabolic conversion of AAI to aristolochic acid Ia (AAIa) being 2-fold higher for rat and 64-fold higher for mouse than human. Results show that the predicted PODs generally fall within the range of PODs derived from the available in vivo studies. This study provides proof of principle for a new method to predict a POD for in vivo nephrotoxicity by integrating in vitro toxicity testing with in silico PBK model-based reverse dosimetry.