Bioactivation and reactivity research advances - 2023 year in review.

Advances in the field of bioactivation have significantly contributed to our understanding and prediction of drug-induced liver injury (DILI). It has been established that many adverse drug reactions, including DILI, are associated with the formation and reactivity of metabolites. Modern methods allow us to detect and characterize these reactive metabolites in earlier stages of drug development, which helps anticipate and circumvent the potential for DILI. Improved in silico models and experimental techniques that better reflect in vivo environments are enhancing predictive capabilities for DILI risk. Further, studies on the mechanisms of bioactivation, including enzyme interactions and the role of individual genetic differences, have provided valuable insights for drug optimizations. Cumulatively, this progress is continually refining our approaches to drug safety evaluation and personalized medicine.

Biotransformation research advances - 2022 year in review.

This annual review is the eighth of its kind since 2016 (Baillie et al. 2016, Khojasteh et al. 2017, Khojasteh et al. 2018, Khojasteh et al. 2019, Khojasteh et al. 2020, Khojasteh et al. 2021, Khojasteh et al. 2022). Our objective is to explore and share articles which we deem influential and significant in the field of biotransformation.

Bioactivation and reactivity research advances - 2022 year in review‡.

With the 50th year mark since the launch of Drug Metabolism and Disposition journal, the field of drug metabolism and bioactivation has advanced exponentially in the past decades (Guengerich 2023).This has, in a major part, been due to the continued advances across the whole spectrum of applied technologies in hardware, software, machine learning (ML), and artificial intelligence (AI). LC-MS platforms continue to evolve to support key applications in the field, and automation is also improving the accuracy, precision, and throughput of these supporting assays. In addition, sample generation and processing is being aided by increased diversity and quality of reagents and bio-matrices so that what is being analyzed is more relevant and translatable. The application of in silico platforms (applied software, ML, and AI) is also making great strides, and in tandem with the more traditional approaches mentioned previously, is significantly advancing our understanding of bioactivation pathways and how these play a role in toxicity. All of this continues to allow the area of bioactivation to evolve in parallel with associated fields to help bring novel or improved medicines to patients with urgent or unmet needs.Shuai Wang and Cyrus Khojasteh, on behalf of the authors.

Quality of Life of People Living with HIV in Australia: The Role of Stigma, Social Disconnection and Mental Health.

HIV is a manageable chronic illness, due to advances in biomedical management. However, many people living with HIV (PLHIV) continue to experience psychosocial challenges, which have been associated with poorer quality of life (QoL). This study aimed to explore how psychosocial factors contributed to the QoL of PLHIV in Australia; specifically, the relationship between HIV-related stigma, social connectedness, mental health, and QoL. Participants were 122 PLHIV attending The Albion Centre (a tertiary HIV clinic in Sydney, Australia), who completed questionnaires which measured HIV-related stigma, social support, mental health symptomology and QoL. Results indicated that HIV-related stigma predicted poorer QoL, as did mental health symptomology. Conversely, social connectedness improved QoL. Additionally, social connectedness was found to mediate the relationship between HIV-related stigma and QoL, whereas the hypothesized moderating role of mental health symptomology on this model was not significant. These findings provide insight into the impact of psychosocial factors on QoL, offering practitioners various points of clinical intervention.

Biotransformation novel advances - 2021 year in review.

Biotransformation field is constantly evolving with new molecular structures and discoveries of metabolic pathways that impact efficacy and safety. Recent review by Kramlinger et al. (2022) nicely captures the future (and the past) of highly impactful science of biotransformation (see the first article). Based on the selected articles, this review was categorized into three sections: (1) new modalities biotransformation, (2) drug discovery biotransformation, and (3) drug development biotransformation (Table 1).

Bioactivation and reactivity research advances - 2021 year in review.

This year's review on bioactivation and reactivity began as a part of the annual review on biotransformation and bioactivation led by Cyrus Khojasteh (see references). Increased contributions from experts in the field led to the development of a stand alone edition for the first time this year focused specifically on bioactivation and reactivity. Our objective for this review is to highlight and share articles which we deem influential and significant regarding the development of covalent inhibitors, mechanisms of reactive metabolite formation, enzyme inactivation, and drug safety. Based on the selected articles, we created two sections: (1) reactivity and enzyme inactivation, and (2) bioactivation mechanisms and safety (Table 1). Several biotransformation experts have contributed to this effort from academic and industry settings.[Table: see text].

Neurotoxicity with high-dose disulfiram and vorinostat used for HIV latency reversal.

OBJECTIVE: The aim of this study was to examine whether administering both vorinostat and disulfiram to people with HIV (PWH) on antiretroviral therapy (ART) is well tolerated and can enhance HIV latency reversal. DESIGN: Vorinostat and disulfiram can increase HIV transcription in PWH on ART. Together, these agents may lead to significant HIV latency reversal. METHODS: Virologically suppressed PWH on ART received disulfiram 2000 mg daily for 28 days and vorinostat 400 mg daily on days 8-10 and 22-24. The primary endpoint was plasma HIV RNA on day 11 relative to baseline using a single copy assay. Assessments included cell-associated unspliced RNA as a marker of latency reversal, HIV DNA in CD4+ T-cells, plasma HIV RNA, and plasma concentrations of ART, vorinostat, and disulfiram. RESULTS: The first two participants (P1 and P2) experienced grade 3 neurotoxicity leading to trial suspension. After 24 days, P1 presented with confusion, lethargy, and ataxia having stopped disulfiram and ART. Symptoms resolved by day 29. After 11 days, P2 presented with paranoia, emotional lability, lethargy, ataxia, and study drugs were ceased. Symptoms resolved by day 23. CA-US RNA increased by 1.4-fold and 1.3-fold for P1 and P2 respectively. Plasma HIV RNA was detectable from day 8 to 37 (peak 81 copies ml-1) for P2 but was not increased in P1 Antiretroviral levels were therapeutic and neuronal injury markers were elevated in P1. CONCLUSION: The combination of prolonged high-dose disulfiram and vorinostat was not safe in PWH on ART and should not be pursued despite evidence of latency reversal.

Future of Biotransformation Science in the Pharmaceutical Industry.

Over the past decades, the number of scientists trained in departments dedicated to traditional medicinal chemistry, biotransformation and/or chemical toxicology have seemingly declined. Yet, there remains a strong demand for such specialized skills in the pharmaceutical industry, particularly within drug metabolism/pharmacokinetics (DMPK) departments. In this position paper, the members of the Biotransformation, Mechanisms, and Pathways Focus Group (BMPFG) steering committee reflect on the diverse roles and responsibilities of scientists trained in the biotransformation field in pharmaceutical companies and contract research organizations. The BMPFG is affiliated with the International Society for the Study of Xenobiotics (ISSX) and was specifically created to promote the exchange of ideas pertaining to topics of current and future interest involving the metabolism of xenobiotics (including drugs). The authors also delve into the relevant education and diverse training skills required to successfully nurture the future cohort of industry biotransformation scientists and guide them toward a rewarding career path. The ability of scientists with a background in biotransformation and organic chemistry to creatively solve complex drug metabolism problems encountered during research and development efforts on both small and large molecular modalities is exemplified in five relevant case studies. Finally, the authors stress the importance and continued commitment to training the next generation of biotransformation scientists who are not only experienced in the metabolism of conventional small molecule therapeutics, but are also equipped to tackle emerging challenges associated with new drug discovery modalities including peptides, protein degraders, and antibodies. SIGNIFICANCE STATEMENT: Biotransformation and mechanistic drug metabolism scientists are critical to advancing chemical entities through discovery and development, yet the number of scientists academically trained for this role is on the decline. This position paper highlights the continuing demand for biotransformation scientists and the necessity of nurturing creative ways to train them and guarantee the future growth of this field.

Novel advances in biotransformation and bioactivation research - 2020 year in review.

This annual review is the sixth of its kind since 2016 (see references). Our objective is to explore and share articles which we deem influential and significant in the field of biotransformation and bioactivation. These fields are constantly evolving with new molecular structures and discoveries of corresponding pathways for metabolism that impact relevant drug development with respect to efficacy and safety. Based on the selected articles, we created three sections: (1) drug design, (2) metabolites and drug metabolizing enzymes, and (3) bioactivation and safety (Table 1). Unlike in years past, more biotransformation experts have joined and contributed to this effort while striving to maintain a balance of authors from academic and industry settings.[Table: see text].

Spatial Distribution Profiles of Emtricitabine, Tenofovir, Efavirenz, and Rilpivirine in Murine Tissues Following In Vivo Dosing Correlate with Their Safety Profiles in Humans.

Emtricitabine (FTC), tenofovir (TFV), efavirenz (EFV), and rilpivirine (RPV) are currently used as components of HIV combination therapy. Although these drugs are widely used in antiretroviral therapy, several organ toxicities related to TFV and EFV have been observed clinically. TFV is associated with nephrotoxicity, whereas EFV-related hepatotoxicity and neurotoxicity have been reported. While the precise molecular mechanisms related to the above-mentioned clinically observed toxicities have yet to be elucidated, understanding the local tissue distribution profiles of these drugs could yield insights into their safety profiles. To date, the distributions of these drugs in tissue following in vivo exposure are poorly understood. Therefore, in this study, we employed a matrix-assisted laser desorption/ionization mass spectrometry imaging method to generate spatial distribution profiles of FTC, TFV, EFV, and RPV in mouse tissues following in vivo dosing of following drug regimens: TFV-FTC-EFV and TFV-FTC-RPV. For this study, liver, brain, kidney, spleen, and heart tissues were obtained from mice (n = 3) following separate oral administration of the above-mentioned drug regimens. Interestingly, EFV was detected in liver, brain, and heart following TFV-FTC-EFV treatment. Additionally, hydroxylated EFV, which encompasses the cytochrome P450-dependent monooxygenated metabolites of EFV, was detected in liver, brain, spleen, and heart tissue sections. Notably, the tissue distribution profiles of RPV and hydroxylated RPV following in vivo dosing of TFV-FTC-RPV were different from EFV/hydroxylated EFV despite RPV belonging to the same drug class as EFV. In conclusion, the observed spatial distribution profiles of the study drugs are in agreement with their safety profiles in humans.

Twelfth-Position Deuteration of Nevirapine Reduces 12-Hydroxy-Nevirapine Formation and Nevirapine-Induced Hepatocyte Death.

Cytochrome P450-dependent metabolism of the anti-HIV drug nevirapine (NVP) to 12-hydroxy-NVP (12-OHNVP) has been implicated in NVP toxicities. We investigated the impact of twelfth-position trideuteration (12-D3NVP) on the hepatic metabolism of and response to NVP. Formation of 12-OHNVP decreased in human (10.6-fold) and mouse (4.6-fold) hepatocytes incubated with 10 µM 12-D3NVP vs NVP. An observed kinetic isotope effect of 10.1 was measured in human liver microsomes. During mouse hepatocyte treatment (400 µM) with NVP or 12-D3NVP, cell death was reduced 30% with 12-D3NVP vs NVP, while glucuronidated and glutathione-conjugated metabolites increased with 12-D3NVP vs NVP. Using mass spectrometry proteomics, changes in hepatocyte protein expression, including an increase in stress marker insulin-like growth factor-binding protein 1 (IGFBP-1), were observed with 12-D3NVP vs NVP. These results demonstrate that while deuteration can reduce P450 metabolite formation, impacts on phase II metabolism and hepatocyte protein expression should be considered when employing deuteration to reduce P450 metabolite-related hepatotoxicity.

Explaining variation in Colorado songbird blood mercury using migratory behavior, foraging guild, and diet.

Methylmercury is a contaminant of growing global concern that has been shown to accumulate in a variety of taxa, including songbirds. Birds in the same area can accumulate mercury to strikingly different levels. While diet and trophic level clearly play an important role in mercury bioaccumulation and biomagnification, other factors including foraging guilds and migratory behavior may influence mercury levels as well. Here we examine interspecific variation in blood mercury levels in songbirds living in the Fountain Creek watershed on the Front Range of Colorado. We found that the species with the highest mercury had blood mercury concentrations over 75 times higher than the species with the lowest levels. Carnivores had the highest blood mercury levels, but ground foraging and long distance migration also were correlated with higher mercury concentrations. This information may shed light on what species are most at risk from mercury pollution and help to target conservation resources at contaminated sites.

Birth Size and Gestational Age Specific Outcomes of Inhaled Nitric Oxide Therapy in Preterm Neonates with Clinically Diagnosed Pulmonary Hypertension.

OBJECTIVE: Among neonates of 22 to 29 weeks' gestational age (GA) who required mechanical ventilation for the treatment of respiratory distress syndrome (RDS) and clinically diagnosed pulmonary hypertension (PH), we tested our hypothesis that the association between early treatment with inhaled nitric oxide (iNO) and survival would vary according to birth size and GA. STUDY DESIGN: Because iNO was not randomly prescribed to patients in this cohort, we used propensity score matching to pair a neonate who received iNO at a chronological age of ≤7 days with an unexposed neonate with similar baseline characteristics. The primary outcome was inhospital mortality, which we evaluated based on size for GA and GA strata using the Cox proportional hazards regression model. RESULTS: Among 1,531 neonates who met study criteria, we created a propensity score matched cohort of 615 pairs of neonates (iNO-exposed and unexposed). The risk of inhospital mortality for iNO-exposed neonates was observed only in the minority (<10%) who were large for GA, though this finding did not persist when matching for illness severity. CONCLUSION: Early treatment with iNO is not associated with survival in most extremely premature neonates with RDS and clinically diagnosed PH when stratified for birth size or GA.

Efavirenz and Efavirenz-like Compounds Activate Human, Murine, and Macaque Hepatic IRE1α-XBP1.

Efavirenz (EFV), a widely used antiretroviral drug, is associated with idiosyncratic hepatotoxicity and dyslipidemia. Here we demonstrate that EFV stimulates the activation in primary hepatocytes of key cell stress regulators: inositol-requiring 1α (IRE1α) and X-box binding protein 1 (XBP1). Following EFV exposure, XBP1 splicing (indicating activation) was increased 35.7-fold in primary human hepatocytes. In parallel, XBP1 splicing and IRE1α phosphorylation (p-IRE1α, active IRE1α) were elevated 36.4-fold and 4.9-fold, respectively, in primary mouse hepatocytes. Of note, with EFV treatment, 47.2% of mouse hepatocytes were apoptotic; which was decreased to 23.9% in the presence of STF 083010, an inhibitor of XBP1 splicing. Experiments performed using pregnane X receptor (PXR)-null mouse hepatocytes revealed that EFV-mediated XBP1 splicing and hepatocyte death were not dependent on PXR, which is a nuclear receptor transcription factor that plays a crucial role in the cellular response to xenobiotics. Interestingly, incubation with the primary metabolite of EFV, 8-hydroxyefavirenz (8-OHEFV), only resulted in 10.3- and 2.9-fold increased XBP1 splicing in human and mouse hepatocytes and no change in levels of p-IRE1α in mouse hepatocytes. To further probe the structure-activity relationship of IRE1α-XBP1 activation by EFV, 16 EFV analogs were employed. Of these, an analog in which the EFV alkyne is replaced with an alkene and an analog in which the oxazinone oxygen is replaced by a carbon stimulated XBP1 splicing in human, mouse, and macaque hepatocytes. These data demonstrate that EFV and compounds sharing the EFV scaffold can activate IRE1α-XBP1 across human, mouse, and macaque species.

Probing Ligand Structure-Activity Relationships in Pregnane†X Receptor (PXR): Efavirenz and 8-Hydroxyefavirenz Exhibit Divergence in Activation.

Efavirenz (EFV), an antiretroviral that interacts clinically with co-administered drugs via activation of the pregnane X receptor (PXR), is extensively metabolized by the cytochromes P450. We tested whether its primary metabolite, 8-hydroxyEFV (8-OHEFV) can activate PXR and potentially contribute to PXR-mediated drug-drug interactions attributed to EFV. Luciferase reporter assays revealed that despite only differing from EFV by an oxygen atom, 8-OHEFV does not activate PXR. Corroborating this, treatment with EFV for 72 h elevated the mRNA abundance of the PXR target gene, Cyp3a11, by approximately 28-fold in primary hepatocytes isolated from PXR-humanized mice, whereas treatment with 8-OHEFV did not result in a change in Cyp3A11 mRNA levels. FRET-based competitive binding assays and isothermal calorimetry demonstrated that even with the lack of ability to activate PXR, 8-OHEFV displays an affinity for PXR (IC50 12.1 µm; KD 7.9 µm) nearly identical to that of EFV (IC50 18.7 µm; KD 12.5 µm). The use of 16 EFV analogues suggest that other discreet changes to the EFV structure beyond the 8-position are well tolerated. Molecular docking simulations implicate an 8-OHEFV binding mode that may underlie its divergence in PXR activation from EFV.

The hormonal sensitivity hypothesis: A review and new findings.

Previous women's health practitioners and researchers have postulated that some women are particularly sensitive to hormonal changes occurring during reproductive events. We hypothesize that some women are particularly sensitive to hormonal changes occurring across their reproductive lifespan. To evaluate this hypothesis, we reviewed findings from the existing literature and findings from our own lab. Taken together, the evidence we present shows a recurring pattern of hormonal sensitivity at predictable but different times across the lifespan of some women (i.e., menarche, the premenstrual phase, hormonal contraceptive use, pregnancy, the postpartum period, and menopause). These findings provide support for the hypothesis that there is a subgroup of women who are more susceptible to physical, psychological, and sexual symptoms related to hormonal shifts or abrupt hormonal fluctuations that occur throughout the reproductive lifespan. We propose that this pattern reflects a Hormonal Sensitivity Syndrome.

Breastfeeding and Postpartum Depression: An Overview and Methodological Recommendations for Future Research.

Emerging research suggests that a relationship exists between breastfeeding and postpartum depression; however, the direction and precise nature of this relationship are not yet clear. The purpose of this paper is to provide an overview of the relationship between breastfeeding and postpartum depression as it has been examined in the empirical literature. Also, the potential mechanisms of action that have been implicated in this relationship are also explored. PubMed and PsycINFO were searched using the keywords: breastfeeding with postpartum depression, perinatal depression, postnatal depression. Results of this search showed that researchers have examined this relationship in diverse ways using diverse methodology. In particular, researchers have examined the relationships between postpartum depression and breastfeeding intention, initiation, duration, and dose. Due to a number of methodological differences among past studies we make some recommendations for future research that will better facilitate an integration of findings. Future research should (1) use standardized assessment protocols; (2) confirm diagnosis through established clinical interview when possible; (3) provide a clear operationalized definition for breastfeeding variables; (4) clearly define the postpartum period interval assessed and time frame for onset of symptoms; (5) be prospective or longitudinal in nature; and (6) take into consideration other potential risk factors identified in the empirical literature.

Breastfeeding and postpartum depression: Assessing the influence of breastfeeding intention and other risk factors.

BACKGROUND: Risk and protective factors for postpartum depression have been extensively studied, and in recent studies an association between breastfeeding and maternal mood has been reported. The present retrospective, cross-sectional study was conducted to evaluate the association between breastfeeding-related variables and postpartum depression (based on Edinburgh Postnatal Depression Scale threshold criteria) within the context of other known risk factors. METHOD: Breastfeeding information, demographic information, and scores on the Edinburgh Postnatal Depression Scale were examined from the Canadian Maternity Experience Survey. This survey contains data collected from 6421 Canadian mothers between October 2006 and January 2007, and 2848 women between five and seven months postpartum were included in the current analyses. RESULTS: In contrast to previous research, logistic regression analyses revealed that when considered within the context of other risk factors, breastfeeding attempt and duration were not associated with postpartum depression at five to seven months postpartum. Although a relationship between the prenatal intention to combination feed and postpartum depression was observed, these variables were no longer related once other potential risk factors were controlled for. Factors that were associated with postpartum depression included lower income, higher perceived stress, lower perceived social support, no history of depression, or no recent history of abuse. LIMITATIONS: A clinical diagnostic instrument was not used and variable selection was restricted to data collected as part of this survey. CONCLUSION: These findings suggest that the association between breastfeeding and postpartum depression reported by previous researchers may in fact be due to alternative risk factors.

A Systematic Review of the Association Between Psychiatric Disturbances and Endometriosis.

OBJECTIVE: An association between endometriosis and psychiatric disturbances has been identified by some researchers. The purpose of this systematic review was to consolidate existing empirical findings to clarify the association between endometriosis and psychiatric conditions. DATA SOURCES: We searched three electronic databases (Medline/PubMed, PsychInfo, and ClinicalTrials.gov) using the following search items: "endometriosis" combined with "mood," "bipolar disorder," "major depressive disorder," "anxiety," "psychiatric," "psychosocial," "antidepressants," "antianxiety," "pharmacotherapy," or "psychotherapy." STUDY SELECTION: We included all relevant articles published in English. We identified 18 original research studies examining the association between endometriosis and psychiatric symptoms, with a combined total of 999 endometriosis patients being examined. DATA EXTRACTION AND SYNTHESIS: Of the 18 studies examined, 14 reported that endometriosis was associated with at least some aspect of reduced psychological functioning or mental health quality of life. Tabulation of raw frequencies of the studies using clinical diagnostic criteria and a comparison group revealed that at least 56.4% of women (44/78) with a diagnosis of endometriosis and 43.6% of women (48/110) without such a diagnosis met the criteria for a psychiatric disorder. CONCLUSION: The limited research suggests that women presenting with endometriosis are at risk for psychosocial disturbances or psychiatric distress. Whether such disruptions are a consequence of endometriosis, the associated chronic gynaecological pain, or another factor such as inflammation remains to be delineated. In the interim, women presenting with symptoms of endometriosis should also be screened for psychosocial and psychiatric disturbances.

Objectif : Une association entre l'endométriose et des perturbations psychiatriques a été identifiée par certains chercheurs. Cette analyse systématique avait pour but de consolider les constatations empiriques existantes en vue de clarifier l'association entre l'endométriose et des troubles psychiatriques. Sources de données : Nous avons mené des recherches dans trois bases de données électroniques (Medline/PubMed, PsychInfo et ClinicalTrials.gov) au moyen des termes suivants : « endometriosis ¼ en combinaison avec « mood ¼, « bipolar disorder ¼, « major depressive disorder ¼, « anxiety ¼, « psychiatric ¼, « psychosocial ¼, « antidepressants ¼, « antianxiety ¼, « pharmacotherapy ¼ ou « psychotherapy ¼. Sélection des études : Nous avons inclus tous les articles pertinents publiés en anglais. Nous avons identifié 18 études originales s'étant penchées sur l'association entre l'endométriose et des symptômes psychiatriques (pour un total combiné de 999 cas d'endométriose soumis à une analyse). Extraction et synthèse des données : Parmi les 18 études examinées, 14 ont signalé que l'endométriose était au moins d'une certaine façon associée à une atténuation du fonctionnement psychologique ou de la qualité de vie liée à la santé mentale. La tabulation des fréquences brutes de ces études au moyen de critères diagnostiques cliniques et d'un groupe de comparaison a révélé qu'au moins 56,4 % des femmes (44/78) ayant obtenu un diagnostic d'endométriose et 43,6 % des femmes (48/110) n'ayant pas obtenu un tel diagnostic satisfaisaient aux critères permettant d'établir la présence d'un trouble psychiatrique. Conclusion : Les recherches limitées semblent indiquer que les femmes qui présentent une endométriose sont exposées à des risques de perturbations psychosociales ou de détresse psychiatrique. La question de savoir si de telles perturbations sont une conséquence de l'endométriose, de la douleur gynécologique chronique connexe ou d'autres facteurs tels que l'inflammation demeure à élucider. Entre-temps, les femmes qui présentent des symptômes d'endométriose devraient également faire l'objet d'un dépistage visant des perturbations psychosociales et psychiatriques.