Timely transition from first-line to second-line antiretroviral therapy (ART) is critical to prevent treatment failure and minimize resistance. The World Health Organization (WHO) recommends switching within 90 days of confirmed virologic failure (VF). This study assessed the timeliness of switching to second-line ART in three HIV care and treatment clinics in Ilala District, Dar es Salaam.

Opsoclonus myoclonus syndrome (OMS) is a rare inflammatory disease of the central nervous system characterized by ocular movements, ataxia, irritability, myoclonus, and sleep disturbances and is thought to result from variable etiologies. We report a case of OMS following severe malaria in a patient living with Human Immunodeficiency Virus (HIV). This is a 47-year-old woman, known to be HIV-positive, for the past 6 years, and on highly active antiretroviral therapy (HAART) with Tenofovir-Lamivudine-Atazanavir, to which she is strictly compliant. Her last viral load was undetectable. Two weeks after being treated for severe malaria due to Plasmodium falciparum, the patient presented with multidirectional ocular saccades associated with trunk myoclonus. This was subsequently followed by aggressive behavior sleep disturbances, and severe ataxia. The diagnosis of post-infectious opsoclonus-myoclonus was made after ruling out an HIV-related central nervous system (CNS) infection and a paraneoplastic origin. Initial management consisted of high doses of intravenous (IV) methylprednisolone which resulted in partial improvement of the symptoms. The subsequent addition of rituximab led to complete resolution of the symptoms and the restoration of functional autonomy. This case suggests a possible relationship between malaria and OMS in the context of HIV infection and highlights the potential benefit of an IV corticosteroid and rituximab combination therapy as a substitute for IV immunoglobulins in resource-limited settings.

Drug resistance to Human Immunodeficiency Virus (HIV) antiretroviral therapy (ART) is a major factor in treatment failure. Resistance monitoring is recommended before initiating ART. However, in Tunisia, the pre-treatment resistance related data are missing. This study aimed to investigate the HIV-1 pre-treatment drug resistance in Tunisia. Viral RNAs were extracted from the plasma samples of 77 ART-naïve patients and used for the sequencing of Reverse Transcriptase (RT) and Protease (PR) regions. 12.9% of variants were shown to have at least one Surveillance Drug Resistance Mutations (SDRM) in RT/PR region. K103N is the most involved SDRM-inducing resistance to NNRTIs (efavirenz, nevirapine, and rilpivirine). In the PR gene, resistance was found in four samples on 46 and 85 codons, affecting the sensitivity for Atazanavir and Lopinavir drugs. The subtying revealed the predominance of the CRF02_AG, followed by the subtype B. This study provides the first baseline information for pre-treatment drug resistance surveillance of HIV-1 variants in Tunisia, which may impede patient management.

The article presents the results of developing optimal conditions for extracting atazanavir using liquid-liquid extraction from physiological fluids (urine, saliva, and blood plasma), as well as identifying and quantifying this substance in extracts using thin-layer chromatography, UV spectrophotometry, and high-performance liquid chromatography.

A South African woman receiving tenofovir, lamivudine and dolutegravir (TLD) with good adherence, developed virological failure with the integrase mutation R263K. Viral suppression was achieved after rapid intensification to dolutegravir 50 mg twice daily combined with atazanavir with ritonavir (ATV/r), with continuation of the nucleoside backbone (dual-anchor regimen). This case highlights the need for earlier resistance testing and specialist-guided salvage therapy for subtype C in resource-limited settings.

Background/Objectives: Macrophages polarized into M1 and M2 phenotypes differentially regulate immune and drug responses. Despite their distinct functional roles, differences in UDP-glucuronosyltransferase (UGT) expression and enzymatic activity between M1 and M2 macrophages remain poorly understood. This study aimed to characterize differential UGT expression in M1 and M2 macrophages and to elucidate how UGT-mediated prostaglandin E2 (PGE2) glucuronidation modulates macrophage inflammatory responses. Methods: THP-1 cells were chemically differentiated into macrophages (M0) and subsequently polarized into M1 and M2 phenotypes. UGT expression profiles were assessed using RT-PCR, quantitative RT-PCR (qRT-PCR), and Western blot. UGT activity was compared by quantifying glucuronide metabolites derived from UGT-specific substrates using LC-MS/MS, along with measurement of free PGE2 and PGE2-glucuronide by ELISA. Pro-inflammatory cytokine expression and secretion in M1 macrophages were quantified using qRT-PCR and ELISA. Results: Expression of UGT1A1, UGT1A4, UGT1A5, UGT1A9, and UGT2B7 were markedly higher in M1 compared with M2 macrophages at both the mRNA and protein levels. Enhanced UGT activity in M1 macrophages was reflected by increased formation of estradiol-3-glucuronide and naloxone-3-glucuronide (both p < 0.01) and was attenuated in a concentration-dependent manner by diclofenac. Furthermore, PGE2 glucuronidation was more pronounced in M1 macrophages, and inhibition of UGTs with atazanavir reduced PGE2-glucuronide formation and pro-inflammatory cytokine production, including IL-1β, IL-6, and TNF-α. Conclusion: UGT-mediated PGE2 glucuronidation in M1 macrophages contributes to the regulation of pro-inflammatory cytokine production. Collectively, these findings support a role for UGTs as modulators of inflammatory signaling, with differential expression and activity between M1 and M2 macrophages.

Hyperbilirubinemia, characterized by elevated total blood bilirubin levels including both unconjugated and conjugated forms, serves as a diagnostic marker for drug-induced liver toxicity associated with a wide range of medications. This study aimed to develop a mechanistic model for assessing hyperbilirubinemia risk using genetic markers. We developed an ordinary differential equation (ODE)-based mechanistic model of human bilirubin metabolism, incorporating key processes such as unconjugated bilirubin synthesis, hepatic uptake, conjugation to form conjugated bilirubin, and elimination via hepatic and renal pathways. The model includes key transporters and enzymes like OATP1B1, MRP2, MRP3, and UGT1A1 involved in bilirubin metabolism. The model was parametrized using in vitro and published human data, validated in healthy subjects and genetic disease cases, and assessed for genetic mutations' impact on bilirubin levels. A 90% reduction in OATP1B1 enzymatic activity increased predicted unconjugated and conjugated bilirubin concentrations (1.58-fold and 2.2-fold, respectively), mimicking data from individuals with mutations in OATP1B1. Sensitivity analysis of OATP1B1, MRP2, and UGT1A1 revealed increased OATP1B1 sensitivity in the presence of low UGT1A1 activity. Model simulations linked nilotinib-induced hyperbilirubinemia to UGT1A1 mutations, and simulations were used to assess the risk of hyperbilirubinemia associated with varying doses of nelfinavir, atazanavir, and TAK-875, based on their off-target effects on transporters. Results demonstrated that uncertainty in free drug tissue concentration may be crucial in hyperbilirubinemia, especially for highly protein-bound drugs. This approach may help assess hyperbilirubinemia risk using a drug's inhibitory in vitro data coupled with patient pharmacogenetic data for OATP1B1, UGT1A1, and MRP2 mutations.

Long-term impact of antiretroviral therapy (ART) on bone health in children living with HIV (CLWH) remains uncertain. We aimed to determine associations of change in bone mineral density (BMD) among CLWH in Uganda in a 2-year prospective sub-study in the CHAPAS-4 randomized trial (ISRCTN22964075). CLWH aged 3-15 years switched to second-line ART including tenofovir alafenamide fumarate-emtricitabine (TAF/FTC) or standard-of-care (SOC) (abacavir (ABC) or zidovudine (ZDV) with dolutegravir (DTG), atazanavir/ritonavir (ATV/r), darunavir/ritonavir (DRV/r) or lopinavir/ritonavir (LPV/r). BMD was assessed by dual-energy X-ray absorptiometry (DXA) at baseline, weeks 48 and 96 and bone turnover markers measured at baseline, week 24, 48, and 96. Robust regression analysis determined associations of BMD and bone turnover markers through week 96. Of 196 participants,167 contributed BMD measurements. Median (IQR) age was 9.9(7.0,12.3) years, 47% male, median (IQR) CD4 T-cell count 797(537,1140) cells/µl and mean (SD) viral load (log10 copies/ml) 4.3(0.8). Change in Procollagen type I N-terminal propeptide (PINP), C-terminal telopeptide of type I collagen (CTX) and height-adjusted (HA) BMD were similar between TAF/FTC and SOC. Greater declines in total-body-less-head (TBLH) BMD were associated with higher baseline TBLH (HA) BMD (Coef. -0.30,95% CI: -0.46, -0.15], p < 0.001) and first-line nevirapine (NVP) exposure (-0.25,95% CI: -0.43, -0.06, p = 0.009). Smaller TBLH HA BMD declines were associated with higher baseline fat-mass (0.06, 95% CI:0.01, 0.11, p = 0.021), higher lumbar spine (LS) HA BMD (0.17, 95% CI:0.03, 0.31, p = 0.015), DRV/r (0.46, p < 0.001,95% CI:0.21,0.71), DTG (0.26, p = 0.041,95% CI:0.01,0.51) or ATV/r (0.28, p = 0.026, 95% CI: 0.03, 0.52) use compared with LPV/r. Smaller declines in TBLH BMD were associated with higher baseline fat mass, higher LS HA BMD, and use of DRV/r, DTG, or ATV/r compared with LPV/r. These findings emphasize the importance of ART selection and body composition in supporting bone health among CLWH.

Approximately one-third of clinical drugs mediate their therapeutic effects through G protein-coupled receptors (GPCRs), highlighting their immense therapeutic relevance. Novel approaches to modulate GPCR activity have the potential to yield unique pharmacological profiles. Conventionally, the G protein and β-arrestin signaling pathways downstream of GPCRs have been viewed as mutually exclusive. Using the in-house developed survival pressure selection (SPS) method, a high-throughput platform for GPCR agonist discovery, we identified an allosteric ligand that stabilizes a GPCR-G protein-β-arrestin megacomplex, thereby mediating sustained receptor signaling following internalization. Remarkably, this compound, atazanavir, exhibits pan-receptor activation across multiple family A GPCRs, including GPR119, β1AR, and β2AR, demonstrating the broad applicability of this regulatory mechanism. This discovery uncovers a distinct mechanism of GPCR regulation, opening alternative avenues for the development of therapeutics targeting GPCRs.

Protease inhibitors (PIs) target the protease (PR) enzyme to suppress viral replication. Their efficacy in human immunodeficiency virus treatment is compromised by the emergence of drug-resistant strains. Therefore, forecasting drug-resistance during viral evolution would help in the design of effective treatment strategies. To this end, we develop a framework that bridges two distinct data sets. First, we train probabilistic models to learn coevolutionary information in observed PR genotypes in different PI treatment regimens. We use these models to infer transition probabilities of point-mutations conditioned on the genotype and the treatment regimen. Second, we train another set of models to infer drug resistance of PR genotypes to different PIs using data of clinically measured drug resistance. We use these models together to simulate evolutionary trajectories and predict drug resistance. Importantly, we use these simulations to forecast the emergence of persistent drug resistant genotypes. Our analysis shows that the dual therapy of Atazanavir (ATV) and Ritonavir (RTV) is the multi-PI treatment regimen least likely to induce drug resistance. We also conduct an exhaustive ablation study of all possible mutations and predict seven point-mutations as critical for drug resistance. Interestingly, our results highlight the necessity of the amino-acid polymorphism of L63P by predicting that it is critical in developing resistance to Nelfinavir (NFV). The results validate that our framework effectively extracts and combines biological information from the distinct data sets of observed genotypes and drug resistance, while also tackling the challenge of sparsity of available sequence data compared to the large combinatorial complexity of protein evolution and changing functionality in dynamic environments.

Bilirubin is a breakdown product of erythrocytes and plays a crucial role in elimination of heme-containing proteins. After its synthesis in the reticuloendothelial system, unconjugated bilirubin is released into plasma and taken up into the liver. In hepatocytes, bilirubin is conjugated and excreted into the gastrointestinal tract via bile, where it is further converted to urobilinoids. There are various genetic factors causing abnormal bilirubin levels in plasma, such as Gilbert syndrome, Crigler-Najjar syndrome, Dubin-Johnson syndrome, and Rotor syndrome. To better understand bilirubin metabolism and its disorders, this study develops a physiologically based computational model incorporating published literature as well as real-world clinical data from the Explorys database. The model simulates bilirubin levels in both healthy individuals and patients with disorders of bilirubin metabolism. Population simulations show that Gilbert syndrome requires a substantial reduction in UDP-glucuronosyltransferase 1A1 activity, while Crigler-Najjar syndrome requires near-complete loss of its function. In contrast, Dubin-Johnson syndrome is characterized by a significant impairment of multidrug resistance-associated protein 2 activity. To also illustrate model behavior under targeted perturbations, we simulated administration of atazanavir in healthy individuals and patients with Gilbert syndrome to investigate its effect on bilirubin levels. Relative to baseline, unconjugated bilirubin maximum concentration (Cmax) increased by 34% in healthy individuals but by 67% in Gilbert syndrome. Overall, this study provides a conceptual and mechanistically informed framework for studying bilirubin homeostasis and the functional consequences of drug administration in health and disease.