Pharmacogenomics in the Nigerian population: the past, the present and the future

Lumefantrine plasma concentrations in uncontrolled conditions among patients treated with artemether-lumefantrine for uncomplicated plasmodium falciparum malaria in Mwanza, Tanzania

BACKGROUND

Therapeutic efficacy of artemether-lumefantrine is highly dependent on adequate systemic exposure to the partner drug lumefantrine particularly day 7 lumefantrine plasma concentration. There has been contradicting findings on the role of the cut-off values in predicting treatment outcomes among malaria patients in malaria endemic regions. This study assesses the day 3 and 7 lumefantrine plasma concentrations including related determinant factors and their influence on treatment outcomes among treated Tanzanian children and adults in uncontrolled conditions (real life condition).

METHODS

Data was nested from an efficacy study employing the WHO protocol, 2015 for monitoring antimalarial drug efficacy. Lumefantrine plasma concentration was measured by high performance liquid chromatography with ultraviolet (HPLC-UV).

RESULTS

Lumefantrine plasma concentrations below 175ng/ml and 200ng/ml on day 3 and 7 did not affect adequate clinical and parasitological response (ACPR) and recurrence of infection (p = 0.428 and 0.239 respectively). Age and baseline parasitemia were not associated to day 3 median lumefantrine plasma concentrations (p = 0.08 and 0.31 respectively) and day 7 lumefantrine plasma concentrations (p = 0.07 and 0.41 respectively). However, the day 3 and day 7 lumefantrine plasma concentrations were significantly higher in males compared to females (p = 0.03 and 0.042 respectively).

CONCLUSION

Lumefantrine plasma concentrations below cut-off points (175ng/ml and 200ng/ml) on day 3 and 7 did not influence treatment outcomes.

Knowledge, attitude and perception of community pharmacists towards pharmacogenomics services in northern Nigeria: a cross-sectional study

Objectives

To evaluate knowledge, attitude and perception of community pharmacists towards pharmacogenomics services.

Methods

A cross-sectional study was conducted among community pharmacists in two cities in Northern Nigeria using a self-administered, validated and pre-tested questionnaire. The data were collected from December 2021 to February 2022 and were analysed using both descriptive and inferential analyses.

Results

A total of 161 completed questionnaires were included in this study (response rate was 61.9%). Most of the respondents were males (59.0%). Only 25.5% had previous pharmacogenomics training but 90.1% indicated an interest in attending pharmacogenomics training in the future. Overall, respondents had moderate knowledge of pharmacogenomics with higher knowledge score found among those who had previous pharmacogenomics training (11.9 ± 1.7 vs 10.5 ± 2.4; p = 0.001), and those with postgraduate qualification (11.7 ± 1.9 vs 10.7 ± 2.3; p = 0.028). The mean attitude score was 6.8 ± 2.0 out of 10.0 indicating a good attitude towards pharmacogenomics services. Those with previous training (8.1 ± 1.7 vs 6.2 ± 1.9; p < 0.001) and those with postgraduate qualification (7.2 ± 2.3 vs 6.6 ± 1.9; p = 0.042) had better attitude towards pharmacogenomics services. The median perception score was 34.0 out of 45.0, indicating a positive perception towards pharmacogenomics. There was a better perception among those with previous pharmacogenomics training (40.0 [21–45] vs 34.0 [0–45]; p = 0.002) and those with postgraduate qualifications (39.0 [0–45] vs 34.0 [21–45]; p = 0.010). Barriers to the implementation of pharmacogenomics included lack of knowledge (89.4%), lack of guidelines (87.5%) and lack of reimbursement (81.4%).

Conclusion

Community pharmacists have a moderate knowledge, a good attitude and a positive perception towards pharmacogenomics services. Those with previous pharmacogenomics training and those with postgraduate qualifications had better knowledge, attitude and perception towards pharmacogenomics services. Lack of knowledge, lack of guidelines and lack of reimbursement were the major barriers to the implementation of pharmacogenomics services in community pharmacies in Nigeria. Pharmacogenomics should be included in pharmacy training curricula to prepare pharmacists for the provision of pharmacogenomics services. Development of local guidelines and a robust reimbursement plan for pharmacogenomics services is recommended.

Dechlorination and demethylation of ochratoxin A enhance blocking activity of PXR activation, suppress PXR expression and reduce cytotoxicity

The pregnane X receptor (PXR) has been established to induce chemoresistance and metabolic diseases. Ochratoxin A (OTA), a mycotoxin, decreases the expression of PXR protein in human primary hepatocytes. OTA is chlorinated and has a methylated lactone ring. Both structures are associated with OTA toxicity. The study was to test the hypothesis that structural modifications differentially impact PXR blocking activity over cytotoxicity. To test this hypothesis, OTA-M and OTA-Cl/M were synthesized. OTA-M lacked the methyl group of the lactone-ring, whereas OTA-Cl/M had neither the methyl group nor the chlorine atom. The blocking activity of PXR activation was determined in a stable cell line, harboring both PXR (coding sequence) and its luciferase element reporter. OTA-Cl/M showed the highest blocking activity, followed by OTA-M and OTA. OTA-Cl/M was 60 times as potent as the common PXR blocker ketoconazole based on calculated IC₅₀ values. OTA-Cl/M decreased by 90 % the expression of PXR protein and was the least cytotoxic among the tested compounds. Molecular docking identified that OTA and its derivatives interacted with different sets of residues in PXR, providing a molecular basis for selectivity. Excessive activation of PXR has been implicated in chemoresistance and metabolic diseases. Downregulation of PXR protein expression likely delivers an effective mechanism against structurally diverse PXR agonists.

Personalized medicine for asthma in tropical regions

PURPOSE OF REVIEW

Precision medicine could help to improve diagnosis and treatment of asthma; however, in the tropics there are special conditions to be considered for applying this strategy. In this review, we analyze recent advances of precision allergology in tropical regions, highlighting its limitations and needs in high-admixed populations living under environments with high exposure to house dust mites and helminth infections.

RECENT FINDINGS

Advances have been made regarding the genetic characterization of the great diversity of populations living in the tropics. Genes involved in shared biological pathways between immune responses to nematodes and the allergic responses suggested new mechanisms of predisposition. Genome wide association studies of asthma are progressively focusing on some highly replicated genes such as those in chromosome 17q31-13, which have been also replicated in African ancestry populations. Some diagnostic difficulties, because of the endemicity of helminth infections, are now more evident in the context of phenotype definition.

SUMMARY

The clinical impact of the advances in precision medicine for asthma in the tropics is still limited and mainly related to component resolved diagnosis. More basic and clinical research is needed to identify genetic, epigenetic, or other biologic markers that allow and accurate definition of phenotypes and endotypes of this heterogeneous disease. This will substantially improve the selection of personalized treatments.