Background

Control of latent tuberculosis infection (LTBI) is a priority in the World Health Organization strategy to eliminate TB. Many high-income, low TB incidence countries have prioritised LTBI screening and treatment in recent migrants. We tested whether a novel model of care, based entirely within primary care, was effective and safe compared to secondary care.

Organic anion transporting polypeptide (OATP) 1B1 and OATP1B3 are important hepatic transporters. We previously identified OATP1B3 being critically implicated in the disposition of abiraterone. We aimed to further investigate the effects of abiraterone on the activities of OATP1B1 and OATP1B3 utilizing a validated endogenous biomarker coproporphyrin I (CP-I). We used OATP1B-transfected cells to characterize the inhibitory potential of abiraterone against OATP1B-mediated uptake of CP-I. Inhibition constant (K_i) was incorporated into our physiologically based pharmacokinetic (PBPK) modeling to simulate the systemic exposures of CP-I among cancer populations receiving either our model-informed 500 mg or clinically approved 1000 mg abiraterone acetate (AA) dosage. Simulated data were compared with clinical CP-I concentrations determined among our nine metastatic prostate cancer patients receiving 500 mg AA treatment. Abiraterone inhibited OATP1B3-mediated, but not OATP1B1-mediated, uptake of CP-I in vitro, with an estimated K_i of 3.93 μM. Baseline CP-I concentrations were simulated to be 0.81 ± 0.26 ng/ml and determined to be 0.72 ± 0.16 ng/ml among metastatic prostate cancer patients, both of which were higher than those observed for healthy subjects. PBPK simulations revealed an absence of OATP1B3-mediated interaction between abiraterone and CP-I. Our clinical observations confirmed that CP-I concentrations remained comparable to baseline levels up to 12 weeks post 500 mg AA treatment. Using CP-I as an endogenous biomarker, we identified the inhibition of abiraterone on OATP1B3 but not OATP1B1 in vitro, which was predicted and observed to be clinically insignificant. We concluded that the interaction risk between AA and substrates of OATP1Bs is low.

Exogenous substances, including drugs and chemicals, can transfer into human seminal fluid and influence male fertility and reproduction. In addition, substances relevant in the context of sports drug testing programs, can be transferred into the urine of a female athlete (after unprotected sexual intercourse) and trigger a so-called adverse analytical finding. Here, the question arises as to whether it is possible to distinguish analytically between intentional doping offenses and unintentional contamination of urine by seminal fluid. To this end, 480 seminal fluids from nonathletes were analyzed to identify concentration ranges and metabolite profiles of therapeutic drugs that are also classified as doping agents. Therefore, a screening procedure was developed using liquid chromatography connected to a triple quadrupole mass spectrometer, and suspect samples (i.e., samples indicating the presence of relevant compounds) were further subjected to liquid chromatography-high-resolution accurate mass (tandem) mass spectrometry. The screening method yielded 90 findings (including aromatase inhibitors, selective estrogen receptor modulators, diuretics, stimulants, glucocorticoids, beta-blockers, antidepressants, and the nonapproved proliferator-activated receptor delta agonist GW1516) in a total of 81 samples, with 91% of these suspected cases being verified by the confirmation method. In addition to the intact drug, phase-I and -II metabolites were also occasionally observed in the seminal fluid. This study demonstrated that various drugs including those categorized as doping agents partition into seminal fluid. Monitoring substances and metabolites may contribute to a better understanding of the distribution and metabolism of exogenous substances in seminal fluid that may be responsible for the impairment of male fertility.

Solute carrier family 6 member 19 (SLC6A19) inhibitors are being studied as therapeutic agents for phenylketonuria. In this work, a potent SLC6A19 inhibitor (RA836) elevated rat kidney uremic toxin indoxyl sulfate (IDS) levels by intensity (arbitrary unit) of 13.7 ± 7.7 compared with vehicle 0.3 ± 0.1 (P = 0.01) as determined by tissue mass spectrometry imaging analysis. We hypothesized that increased plasma and kidney levels of IDS could be caused by the simultaneous inhibition of both Slc6a19 and a kidney IDS transporter responsible for excretion of IDS into urine. To test this, we first confirmed the formation of IDS through tryptophan metabolism by feeding rats a Trp-free diet. Inhibiting Slc6a19 with RA836 led to increased IDS in these rats. Next, RA836 and its key metabolites were evaluated in vitro for inhibiting kidney transporters such as organic anion transporter (OAT)1, OAT3, and breast cancer resistance protein (BCRP). RA836 inhibits BCRP with an IC₅₀ of 0.045 μM but shows no significant inhibition of OAT1 or OAT3. Finally, RA836 analogs with either potent or no inhibition of SLC6A19 and/or BCRP were synthesized and administered to rats fed a normal diet. Plasma and kidney samples were collected to quantify IDS using liquid chromatography–mass spectrometry. Neither a SLC6A19 inactive but potent BCRP inhibitor nor a SLC6A19 active but weak BCRP inhibitor raised IDS levels, whereas compounds inhibiting both transporters caused IDS accumulation in rat plasma and kidney, supporting the hypothesis that rat Bcrp contributes to the excretion of IDS. In summary, we identified that inhibiting Slc6a19 increases IDS formation, while simultaneously inhibiting Bcrp results in IDS accumulation in the kidney and plasma.

Exercise significantly alters human physiological functions, such as increasing cardiac output and muscle blood flow and decreasing glomerular filtration rate (GFR) and liver blood flow, thereby altering the absorption, distribution, metabolism, and excretion of drugs. In this study, we aimed to establish a database of human physiological parameters during exercise and to construct equations for the relationship between changes in each physiological parameter and exercise intensity, including cardiac output, organ blood flow (e.g., muscle blood flow and kidney blood flow), oxygen uptake, plasma pH and GFR, etc. The polynomial equation P = a_iHRⁱ was used for illustrating the relationship between the physiological parameters (P) and heart rate (HR), which served as an index of exercise intensity. The pharmacokinetics of midazolam, quinidine, digoxin, and lidocaine during exercise were predicted by a whole-body physiologically based pharmacokinetic (WB-PBPK) model and the developed database of physiological parameters following administration to 100 virtual subjects. The WB-PBPK model simulation results showed that most of the observed plasma drug concentrations fell within the 5^th–95^th percentiles of the simulations, and the estimated peak concentrations (C_max) and area under the curve (AUC) of drugs were also within 0.5–2.0 folds of observations. Sensitivity analysis showed that exercise intensity, exercise duration, medication time, and alterations in physiological parameters significantly affected drug pharmacokinetics and the net effect depending on drug characteristics and exercise conditions. In conclusion, the pharmacokinetics of drugs during exercise could be quantitatively predicted using the developed WB-PBPK model and database of physiological parameters.

In this study, the nonclinical pharmacokinetics of OLX702A-075-16, an RNA interference therapeutic currently in development, were investigated. OLX702A-075-16 is a novel N-acetylgalactosamine conjugated asymmetric small-interfering RNA (GalNAc-asiRNA) used for the treatment of an undisclosed liver disease. Its unique 16/21-mer asymmetric structure reduces nonspecific off-target effects without compromising efficacy. We investigated the plasma concentration, tissue distribution, metabolism, and renal excretion of OLX702A-075-16 following a subcutaneous administration in mice and rats. For bioanalysis, high-performance liquid chromatography with fluorescence detection was used. The results showed rapid clearance from plasma (0.5 to 1.5 hours of half-life) and predominant distribution to the liver and/or kidney. Less than 1% of the liver concentration of OLX702A-075-16 was detected in the other tissues. Metabolite profiling using liquid chromatography coupled with high-resolution mass spectrometry revealed that the intact duplex OLX702A-075-16 was the major compound in plasma. The GalNAc moiety was predominantly metabolized from the sense strand in the liver, with the unconjugated sense strand of OLX702A-075-16 accounting for more than 95% of the total exposure in the rat liver. Meanwhile, the antisense strand was metabolized by the sequential loss of nucleotides from the 3'-terminus by exonuclease, with the rat liver samples yielding the most diverse truncated forms of metabolites. Urinary excretion over 96 hours was less than 1% of the administered dose in rats. High plasma protein binding of OLX702A-075-16 likely inhibited its clearance through renal filtration.

Organic anion transporting polypeptides (OATP, gene symbol SLCO) are well-recognized key determinants for the absorption, distribution, and excretion of a wide spectrum of endogenous and exogenous compounds including many antineoplastic agents. It was therefore proposed as a potential drug target for cancer therapy. In our previous study, it was found that low-dose X-ray and carbon ion irradiation both upregulated the expression of OATP family member OATP1A2 and in turn, led to a more dramatic killing effect when cancer cells were cotreated with antitumor drugs such as methotrexate. In the present study, the underlying mechanism of the phenomenon was explored in breast cancer cell line MCF-7. It was found that the nonreceptor tyrosine kinase v-YES-1 Yamaguchi sarcoma viral oncogene homolog 1 (YES-1) was temporally coordinated with the change of OATP1A2 after irradiation. The overexpression of YES-1 significantly increased OATP1A2 both at the mRNA and protein level. The signal transducer and activator of transcription 3 (STAT3) pathway is likely the downstream target of YES-1 because phosphorylation and nuclear accumulation of STAT3 were both enhanced after overexpressing YES-1 in MCF-7 cells. Further investigation revealed that there are two possible binding sites of STAT3 localized at the upstream sequence of SLCO1A2, the encoding gene of OATP1A2. Electrophoretic mobility shift assay and chromatin immunoprecipitation analysis suggested that these two sites bound to STAT3 specifically and the overexpression of YES-1 significantly increased the association of the transcription factor with the putative binding sites. Finally, inhibition or knockdown of YES-1 attenuated the induction effect of radiation on the expression of OATP1A2.

Sterol 12α-hydroxylase (CYP8B1) is the unique P450 enzyme with sterol 12-oxidation activity, playing an exclusive role in 12α-hydroxylating intermediates along the bile acid (BA) synthesis pathway. Despite the long history of BA metabolism studies, it is unclear whether CYP8B1 catalyzes 12α-hydroxylation of C₂₇ BAs, the key intermediates shuttling between mitochondria and peroxisomes. This work provides robust in vitro evidence that both microsomal and recombinant CYP8B1 enzymes catalyze the 12α-hydroxylation of dihydroxycoprostanic acid (DHCA) into trihydroxycoprostanic acid (THCA). On the one hand, DHCA 12α-hydroxylation reactivity is conservatively detected in liver microsomes of both human and preclinical animals. The reactivity of human tissue fractions conforms well with the selectivity of CYP8B1 mRNA expression, while the contribution of P450 enzymes other than CYP8B1 is excluded by reaction phenotyping in commercial recombinant enzymes. On the other hand, we prepared functional recombinant human CYP8B1 proteins according to a recently published protocol. Titration of the purified CYP8B1 proteins with either C4 (7α-hydroxy-4-cholesten-3-one) or DHCA yields expected blue shifts of the heme Soret peak (type I binding). The recombinant CYP8B1 proteins efficiently catalyze 12α-hydroxylation of both DHCA and C4, with substrate concentration occupying half of the binding sites of 3.0 and 1.9 μM and k_cat of 3.2 and 2.6 minutes^–1, respectively. In summary, the confirmed role of CYP8B1 in 12α-hydroxylation of C₂₇ BAs has furnished the forgotten passageway in the BA synthesis pathway. The present finding might have opened a new window to consider the biology of CYP8B1 in glucolipid metabolism and to evaluate CYP8B1 inhibition as a therapeutic approach of crucial interest for metabolic diseases.

Early detection of drug-drug interactions (DDIs) can facilitate timely drug development decisions, prevent unnecessary restrictions on patient enrollment, resulting in clinical study populations that are not representative of the indicated study population, and allow for appropriate dose adjustments to ensure safety in clinical trials. All of these factors contribute to a streamlined drug approval process and enhanced patient safety. Here we describe a new approach for early prediction of the magnitude of change in exposure for cytochrome P450 (P450) CYP3A4-related DDIs of small-molecule anticancer drugs based on the model-based extrapolation of human-CYP3A4-transgenic mice pharmacokinetics to humans. Victim drugs brigatinib and lorlatinib were evaluated with the new approach in combination with the perpetrator drugs itraconazole and rifampicin. Predictions of the magnitude of change in exposure deviated at most 0.99- to 1.31-fold from clinical trial results for inhibition with itraconazole, whereas exposure predictions for the induction with rifampicin were less accurate, with deviations of 0.22- to 0.48-fold. Results for the early prediction of DDIs and their clinical impact appear promising for CYP3A4 inhibition, but validation with more victim and perpetrator drugs is essential to evaluate the performance of the new method.

Over the past 20 years, quantitative proteomics has contributed a wealth of protein expression data, which are currently used for a variety of systems pharmacology applications, as a complement or a surrogate for activity of the corresponding proteins. A symposium at the 25th North American International Society for the Study of Xenobiotics meeting, in Boston, in September 2023, was held to explore current and emerging applications of quantitative proteomics in translational pharmacology and strategies for improved integration into model-informed drug development based on practical experience of each of the presenters. A summary of the talks and discussions is presented in this perspective alongside future outlook that was outlined for future meetings.

ATP-binding cassette transporter subfamily G member 2 (ABCG2) is a membrane-bound transporter responsible for the efflux of various xenobiotics and endobiotics, including protoporphyrin IX (PPIX), an intermediate in the heme biosynthesis pathway. Certain genetic mutations and chemicals impair the conversion of PPIX to heme and/or increase PPIX production, leading to PPIX accumulation and toxicity. In mice, deficiency of ABCG2 protects against PPIX-mediated phototoxicity and hepatotoxicity by modulating PPIX distribution. In addition, in vitro studies revealed that ABCG2 inhibition increases the efficacy of PPIX-based photodynamic therapy by retaining PPIX inside target cells. In this review, we discuss the roles of ABCG2 in modulating the tissue distribution of PPIX, PPIX-mediated toxicity, and PPIX-based photodynamic therapy.

The regulation of drug-metabolizing enzymes and transporters by cytokines has been extensively studied in vitro and in clinic. Cytokine-mediated suppression of cytochrome P450 (CYP) or drug transporters may increase or decrease the systemic clearance of drug substrates that are primarily cleared via these pathways; neutralization of cytokines by therapeutic proteins may thereby alter systemic exposures of such drug substrates. The Food and Drug Administration recommends evaluating such clinical drug interactions during clinical development and has provided labeling recommendations for therapeutic proteins. To determine the clinical relevance of these drug interactions to dose adjustments, trends in steady-state exposures of CYP-sensitive substrates coadministered with cytokine modulators as reported in the University of Washington Drug Interaction Database were extracted and examined for each of the CYPs. Coadministration of cytochrome P450 family 3 subfamily A (CYP3A) (midazolam/simvastatin), cytochrome P450 subfamily 2C19 (omeprazole), or cytochrome P450 subfamily 1A2 (caffeine/tizanidine) substrates with anti-interleukin-6 and with anti-interleukin-23 therapeutics led to changes in systemic exposures of CYP substrates ranging from ~ –58% to ~35%; no significant trends were observed for cytochrome P450 subfamily 2D6 (dextromethorphan) and cytochrome P450 subfamily 2C9 (warfarin) substrates. Although none of these changes in systemic exposures have been reported as clinically meaningful, dose adjustment of midazolam for optimal sedation in acute care settings has been reported. Simulated concentration-time profiles of midazolam under conditions of elevated cytokine levels when coadministered with tocilizumab, suggest a ~six- to sevenfold increase in midazolam clearance, suggesting potential implications of cytokine–CYP drug interactions on dose adjustments of sensitive CYP3A substrates in acute care settings. Additionally, this article also provides a brief overview of nonclinical and clinical assessments of cytokine–CYP drug interactions in drug discovery and development.

The precision medicine initiative has driven a substantial change in the way scientists and health care practitioners think about diagnosing and treating disease. While it has long been recognized that drug response is determined by the intersection of genetic, environmental, and disease factors, improvements in technology have afforded precision medicine guided dosing of drugs to improve efficacy and reduce toxicity. Pharmacometabolomics aims to evaluate small molecule metabolites in plasma and/or urine to help evaluate mechanisms that predict and/or reflect drug efficacy and toxicity. In this mini review, we provide an overview of pharmacometabolomic approaches and methodologies. Relevant examples where metabolomic techniques have been used to better understand drug efficacy and toxicity in major depressive disorder and cancer chemotherapy are discussed. In addition, the utility of metabolomics in drug development and understanding drug metabolism, transport, and pharmacokinetics is reviewed. Pharmacometabolomic approaches can help describe factors mediating drug disposition, efficacy, and toxicity. While important advancements in this area have been made, there remain several challenges that must be overcome before this approach can be fully implemented into clinical drug therapy.

A STING (stimulator of interferon genes) agonist GSK3996915 under investigation in early discovery for hepatitis B was orally dosed to a mouse model for understanding the parent drug distribution in liver, the target organ. Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) was used to quantify the distribution of GSK3996915 in liver collected from mice administered a single oral dose at 90 mg/kg. GSK3996915 was detected with a zonal distribution localized in the portal triad and highly concentrated in the main bile ducts, indicating clearance through biliary excretion. High spatial resolution imaging showed the distribution of the parent drug localized to the cellular populations in the sinusoids, including the Kupffer cells. Additionally, a series of drug-related metabolites were observed to be localized in the central zones of the liver. These results exemplify the potential of utilizing MALDI IMS for measuring not only quantitative drug distribution and target exposure but also drug metabolism and elimination in a single suite of experiments.

Drug–drug interaction (DDI) assessment of therapeutic peptides is an evolving area. The industry generally follows DDI guidelines for small molecules, but the translation of data generated with commonly used in vitro systems to in vivo is sparse. In the current study, we investigated the ability of advanced human hepatocyte in vitro systems, namely HepatoPac, spheroids, and Liver-on-a-chip, to assess potential changes in regulation of CYP1A2, CYP2B6, CYP3A4, SLCO1B1, and ABCC2 in the presence of selected therapeutic peptides, proteins, and small molecules. The peptide NN1177, a glucagon and GLP-1 receptor co-agonist, did not suppress mRNA expression or activity of CYP1A2, CYP2B6, and CYP3A4 in HepatoPac, spheroids, or Liver-on-a-chip; these findings were in contrast to the data obtained in sandwich cultured hepatocytes. No effect of NN1177 on SLCO1B1 and ABCC2 mRNA was observed in any of the complex systems. The induction magnitude differed across the systems (e.g., rifampicin induction of CYP3A4 mRNA ranged from 2.8-fold in spheroids to 81.2-fold in Liver-on-a-chip). Small molecules, obeticholic acid and abemaciclib, showed varying responses in HepatoPac, spheroids, and Liver-on-a-chip, indicating a need for EC₅₀ determinations to fully assess translatability data. HepatoPac, the most extensively investigated in this study (3 donors), showed high potential to investigate DDIs associated with CYP regulation by therapeutic peptides. Spheroids and Liver-on-a-chip were only assessed in one hepatocyte donor and further evaluations are required to confirm their potential. This study establishes an excellent foundation toward the establishment of more clinically-relevant in vitro tools for evaluation of potential DDIs with therapeutic peptides.

Pregnane X receptor (PXR) belongs to the nuclear receptor superfamily that plays a crucial role in hepatic physiologic and pathologic conditions. Phase separation is a process in which biomacromolecules aggregate and condense into a dense phase as liquid condensates and coexist with a dilute phase, contributing to various cellular and biologic functions. Until now, whether PXR could undergo phase separation remains unclear. This study aimed to investigate whether PXR undergoes phase separation. Analysis of the intrinsically disordered regions (IDRs) using algorithm tools indicated a low propensity of PXR to undergo phase separation. Experimental assays such as hyperosmotic stress, agonist treatment, and optoDroplets assay demonstrated the absence of phase separation for PXR. OptoDroplets assay revealed the inability of the fusion protein of Cry2 with PXR to form condensates upon blue light stimulation. Moreover, phase separation of PXR did not occur even though the mRNA and protein expression levels of PXR target, cytochrome P450 3A4, changed after sorbitol treatment. In conclusion, for the first time, these findings suggested that exogenous PXR does not undergo phase separation following activation or under hyperosmotic stress in nucleus of cells.

Protein abundance data of drug-metabolizing enzymes and transporters (DMETs) are useful for scaling in vitro and animal data to humans for accurate prediction and interpretation of drug clearance and toxicity. Targeted DMET proteomics that relies on synthetic stable isotope-labeled surrogate peptides as calibrators is routinely used for the quantification of selected proteins; however, the technique is limited to the quantification of a small number of proteins. Although the global proteomics-based total protein approach (TPA) is emerging as a better alternative for large-scale protein quantification, the conventional TPA does not consider differential sequence coverage by identifying unique peptides across proteins. Here, we optimized the TPA approach by correcting protein abundance data by the sequence coverage, which was applied to quantify 54 DMETs for characterization of 1) differential tissue DMET abundance in the human liver, kidney, and intestine, and 2) interindividual variability of DMET proteins in individual intestinal samples (n = 13). Uridine diphosphate-glucuronosyltransferase 2B7 (UGT2B7), microsomal glutathione S-transferases (MGST1, MGST2, and MGST3) carboxylesterase 2 (CES2), and multidrug resistance-associated protein 2 (MRP2) were expressed in all three tissues, whereas, as expected, four cytochrome P450s (CYP3A4, CYP3A5, CYP2C9, and CYP4F2), UGT1A1, UGT2B17, CES1, flavin-containing monooxygenase 5, MRP3, and P-glycoprotein were present in the liver and intestine. The top three DMET proteins in individual tissues were: CES1>CYP2E1>UGT2B7 (liver), CES2>UGT2B17>CYP3A4 (intestine), and MGST1>UGT1A6>MGST2 (kidney). CYP3A4, CYP3A5, UGT2B17, CES2, and MGST2 showed high interindividual variability in the intestine. These data are relevant for enhancing in vitro to in vivo extrapolation of drug absorption and disposition and can be used to enhance the accuracy of physiologically based pharmacokinetic prediction of systemic and tissue concentration of drugs.

Hydrolases represent an essential class of enzymes indispensable for the metabolism of various clinically essential medications. Individuals exhibit marked differences in the expression and activation of hydrolases, resulting in significant variability in the pharmacokinetics (PK) and pharmacodynamics (PD) of drugs metabolized by these enzymes. The regulation of hydrolase expression and activity involves both genetic polymorphisms and nongenetic factors. This review examines the current understanding of genetic and nongenetic regulators of six clinically significant hydrolases, including carboxylesterase (CES)-1 CES2, arylacetamide deacetylase (AADAC), paraoxonase (PON)-1 PON3, and cathepsin A (CTSA). We explore genetic variants linked to the expression and activity of the hydrolases and their effects on the PK and PD of their substrate drugs. Regarding nongenetic regulators, we focus on the inhibitors and inducers of these enzymes. Additionally, we examine the developmental expression patterns and gender differences in the hydrolases when pertinent information was available. Many genetic and nongenetic regulators were found to be associated with the expression and activity of the hydrolases and PK and PD. However, hydrolases remain generally understudied compared with other drug-metabolizing enzymes, such as cytochrome P450s. The clinical significance of genetic and nongenetic regulators has not yet been firmly established for the majority of hydrolases. Comprehending the mechanisms that underpin the regulation of these enzymes holds the potential to refine therapeutic regimens, thereby enhancing the efficacy and safety of drugs metabolized by the hydrolases.

The antitumor effect of cardiotonic steroids (CTS) has stimulated the search for new methods to evaluate both kinetic and thermodynamic aspects of their binding to Na⁺/K⁺-ATPase (IUBMB Enzyme Nomenclature). We propose a real-time assay based on a chromogenic substrate for phosphatase activity (pNPPase activity), using only two concentrations with an inhibitory progression curve, to obtain the association rate (k_on), dissociation rate (k_off), and equilibrium (K_i) constants of CTS for the structure-kinetics relationship in drug screening. We show that changing conditions (from ATPase to pNPPase activity) resulted in an increase of K_i of the cardenolides digitoxigenin, essentially due to a reduction of k_on. In contrast, the K_i of the structurally related bufadienolide bufalin increased much less due to the reduction of its k_off partially compensating the decrease of its k_on. When evaluating the kinetics of 15 natural and semisynthetic CTS, we observed that both k_on and k_off correlated with K_i (Spearman test), suggesting that differences in potency depend on variations of both k_on and k_off. A rhamnose in C3 of the steroidal nucleus enhanced the inhibitory potency by a reduction of k_off rather than an increase of k_on. Raising the temperature did not alter the k_off of digitoxin, generating a H (k_off) of –10.4 ± 4.3 kJ/mol, suggesting a complex dissociation mechanism. Based on a simple and inexpensive methodology, we determined the values of k_on, k_off, and K_i of the CTS and provided original kinetics and thermodynamics differences between CTS that could help the design of new compounds.

ABSTRACTDespite global consensus on the importance of male involvement in family planning, disparities persist in low- and middle-income countries, where women continue to bear the responsibility for these initiatives. The Philippines, with a high fertility rate and unmet family planning needs, exemplifies this challenge. We present the experiences and lessons learned from implementing the no-scalpel vasectomy (NSV) program in Davao City, showcasing its potential for increasing male engagement in family planning decisions. Launched in 2008, the program aimed to address gender disparity by promoting NSV as a safe and effective contraceptive alternative to female-centric methods. Through the use of culturally sensitive information campaigns and couple-focused counseling, the program challenged traditional notions of masculinity and encouraged shared decision-making. Strong local government commitment and public-private partnerships played key roles in driving the program’s success. Results showed an average annual increase of 80% in NSV clients over the past 3 years compared to before the COVID-19 pandemic, underscoring its effectiveness. The program presents a compelling intervention model for similar initiatives, highlighting how overcoming cultural barriers, infrastructure limitations, and budgetary constraints through policy advocacy, strategic partnerships, and tailored approaches can significantly boost male involvement in family planning and improve reproductive health outcomes within communities.

ABSTRACTIntroduction:Since the health information system (HIS) in public health care services in Serbia was introduced in 2009, it has gradually expanded. However, it is unclear how well the HIS components have developed and the whole system’s stage of maturity.Method:In June–September 2021, a maturity assessment of the Serbian HIS was conducted for the first time using the HIS Stages of Continuous Improvement (SOCI) toolkit. The toolkit measures HIS status across 5 HIS domains: leadership and governance, management and workforce, information and communication technology (ICT), standards and interoperability, and data quality and use. The domains were further divided into 13 components and 39 subcomponents whose maturity stage was assessed on a 5-point Likert scale, indicating the level of development: (1) emerging/ad hoc; (2) repeatable; (3) defined; (4) managed; and (5) optimized. The toolkit was applied in a working group of 32 professionals and experts who were engaged in developing the new national eHealth strategy and action plan.Results:The overall maturity score of the Serbian HIS was 1.6, which indicates a low level. The highest baseline score (2) was given to the standards and interoperability domain, and the lowest (1.1) was given to ICT infrastructure. The remaining 3 domains (leadership and governance, Management and Workforce, and Data Quality and Use) were similarly rated (1.7, 1.7, and 1.6, respectively).Conclusion:A baseline assessment of the maturity level of Serbian HIS indicates that the majority of components are between the emerging/ad hoc stage and repeatable, which represent isolated, ad hoc efforts, with some basic processes in place and existing and accessible policies. This exercise provided an opportunity to address identified weaknesses in the upcoming national eHealth strategy.

ABSTRACTIntroduction:Emergency contraceptive pills (ECPs) are effective and can be used safely at any age repeatedly within the same cycle. They are often favored by youth yet are underutilized. Private facilities can increase ECP access but present barriers including cost. Identifying effective public-sector ECP distribution models can help ensure equitable access. The Malawi Ministry of Health developed a strategy to improve ECP access in 2020. We documented ECP provision through select public, youth-serving channels recommended by the strategy: general and youth-specific outreach, paid and unpaid community health workers (CHWs), and youth clubs.Methods:We conducted this mixed methods study from November 2022–March 2023 in 2 rural districts (Mchinji and Phalombe) implementing the strategy. We conducted qualitative interviews with 10 national stakeholders, 46 providers, and 24 clients aged 15–24 years about ECP service delivery. Additionally, 25 providers collected quantitative tally data about clients seeking ECPs. We analyzed qualitative data using grounded theory and quantitative data descriptively.Results:Stakeholders and providers reported ECP uptake increased in geographies where the strategy was implemented, especially among youth. Providers documented 3,988 client visits for ECPs over 3 months. Of these visits, 26% were from male clients, 36% were from clients aged younger than 20 years, and 64% received ECPs for the first time. Across channels, youth club leaders and unpaid CHWs reported the most client visits per provider and served the youngest clients. However, no ECPs were dispensed during 29% of visits due to stock-outs. While many providers were supportive of youth accessing ECPs, most held unfavorable attitudes toward repeat use.Conclusion:ECP access should be expanded through provision in the studied channels, especially youth clubs and CHWs. However, to meet demand, the supply chain must be strengthened. We recommend addressing providers’ attitudes about repeat use to ensure informed method choice.

ABSTRACTIntroduction:Health risks associated with short interpregnancy intervals, coupled with women’s desires to avoid pregnancy following childbirth, underscore the need for effective postpartum family planning programs. The antenatal period provides an opportunity to intervene; however, evidence is limited on the effectiveness of interventions aimed at reaching women in the antenatal period to increase voluntary postpartum family planning in low- and middle-income countries (LMICs). This systematic review aimed to identify and describe interventions in LMICs that attempted to increase postpartum contraceptive use via contacts with pregnant women in the antenatal period.Methods:Studies published from January 2012 to July 2022 were considered if they were conducted in LMICs, evaluated an intervention delivered during the antenatal period, were designed to affect postpartum contraceptive use, were experimental or quasi-experimental, and were published in French or English. The main outcome of interest was postpartum contraceptive use within 1 year after birth, defined as the use of any method of contraception at the time of data collection. We searched EMBASE, Global Health, and Medline and manually searched the reference lists from studies included in the full-text screening.Results:We double-screened 771 records and included 34 reports on 31 unique interventions in the review. Twenty-three studies were published from 2018 on, with 21 studies conducted in sub-Saharan Africa. Approximately half of the study designs (n=16) were randomized controlled trials, and half (n=15) were quasi-experimental. Interventions were heterogeneous. Among the 24 studies that reported on the main outcome of interest, 18 reported a positive intervention effect, with intervention recipients having greater contraceptive use in the first year postpartum.Conclusion:While the studies in this systematic review were heterogeneous, the findings suggest that interventions that included a multifaceted package of initiatives appeared to be most likely to have a positive effect.

ABSTRACTTraining health workers is one of the biggest challenges and cost drivers when introducing a new contraceptive method or service delivery innovation. PATH developed a digital training curriculum for family planning providers who are learning to offer subcutaneous DMPA (DMPA-SC), including through self-injection, as an option among a range of contraceptive methods. The DMPA-SC eLearning course for health workers includes 10 lessons with an emphasis on informed choice counseling and training clients to self-inject. In partnership with Ministries of Health in Senegal and Uganda, the course was rolled out in select areas in 2019–2020, including during the COVID-19 pandemic when physical distancing requirements restricted in-person training. We conducted evaluations in both countries to assess the practical application of this digital training approach for contraceptive introduction. The evaluation consisted of a post-training survey, an observational assessment conducted during post-training supportive supervision, and an estimation of training costs.In both countries, a majority (88.6% in Uganda and 64.3% in Senegal) scored above 80% on a DMPA-SC knowledge test following the training. In Senegal, where there was a comparison group of providers trained in person, those providers scored similar on the post-test to eLearners. Providers in both groups and in both countries felt more prepared to administer DMPA-SC or offer self-injection to clients after receiving a supervision visit (93%–98% of eLearners felt very prepared after supervision as compared to 45%–72% prior). The evaluation results suggest that digital approaches offer a number of benefits, can be cost-effective, and are most optimal when blended with in-person training and/or supportive supervision.

ABSTRACTIntroduction: Nigeria has the highest number of children who have not received any vaccines in Africa. The training-of-trainers (TOT) model used to train program managers (PMs) and health care workers (HCWs) is ineffective for adult learning and limits immunization programs’ success. We incorporated adult learning principles (ALPs) in designing and delivering TOT for immunization PMs and HCWs to use data to engage communities for tailored immunization strategies.Methods: Our study was implemented in 3 local government areas (LGAs) of the Federal Capital Territory, Nigeria. A training curriculum was developed, integrating ALPs and technical and operational content based on best practices in delivering immunization training and the training needs assessment findings. State PMs (n=10), LGA PMs (n=30), and HCWs (n=42) were trained on the human-centered design for tailoring immunization programs (HCD-TIP) approaches using ALPs. We used interviews and surveys with purposively and conveniently sampled PMs and HCWs, respectively, and observations to assess participants’ satisfaction, knowledge and competence, behavior changes, and results. The interviews were analyzed thematically, and surveys were statistically.Results: There was a high level of satisfaction with the training among LGA PMs (100%), state PMs (91%), and HCWs (85%), with significant knowledge and competence improvements post-training (P<.001). The trained participants conducted 2 HCD sessions with 24 undervaccinated communities and co-designed 24 prototype solutions for testing. Results showed increased coverage of the pentavalent vaccine first dose (54%) and third dose (188%) across 12 participating communities. Improved community colaboration, communication skills, and data-driven approaches were the most cited behavior changes in practice.Conclusion: The application of ALPs in training, use of HCD-TIP approaches and tools, and supportive supervision enhanced PMs’ and HCWs’ capacity for tailored interventions. Countries should consider adopting a holistic approach that focuses on using these approaches in immunization programs to strengthen the health system for equitable vaccine coverage.

ABSTRACTWe describe the development, implementation, and evaluation of a novel twinning approach: the Twinning Partnership Network (TPN). Twinning is a well-known approach to peer learning that has been used in a variety of settings to build organizational capacity. Although twinning takes many forms, the heart of the approach is that institutions with shared characteristics collaborate via sharing information and experiences to achieve a specific goal. We adapted a twinning partnership strategy developed by the World Health Organization to create a network of like-minded health institutions. The key innovation of the TPN is the network, which ensures that an institution always has a high-performing peer with whom to partner on a specific topic area of interest. We identified 10 hospitals and 30 districts in Rwanda to participate in the TPN. These districts and hospitals participated in a kickoff workshop in which they identified capacity gaps, clarified goals, and selected twinning partners. After the workshop, districts and hospitals participated in exchange visits, coaching visits, and virtual and in-person learning events. We found that districts and hospitals that selected specific areas and worked on them throughout the duration of the TPN with their peers improved their performance significantly when compared with those that selected and worked on other areas. Accreditation scores improved by 5.6% more in hospitals selecting accreditation than those that did not. Districts that selected improving community-based health insurance coverage improved by 4.8% more than districts that did not select this topic area. We hypothesize that these results are due to senior management’s interest and motivation to improve in these specific areas, the motivation gained by learning from high-performing peers with similar resources, and context-specific knowledge sharing from peer hospitals and districts.

ABSTRACTPolitics is one of the critical factors that influence health policy agendas. However, scholarly efforts, especially in low- and middle-income countries, rarely focus on how politics influence health policy agenda-setting. We conducted a qualitative document review to examine the factors that led to developing the free primary health care policy for maternal health in Papua New Guinea. We also discuss mechanisms through which national politics, as an overriding factor, influenced the development of the policy. The review draws on Kingdon’s multiple-stream model for agenda-setting and incorporates theoretical insights from Fox and Reich’s framework for analyzing the politics of health reform for universal health coverage in low- and middle-income countries.

Mitochondrial dysfunction is a hallmark of many genetic neurodegenerative diseases, but therapeutic options to reverse mitochondrial dysfunction are limited. While recent studies support the possibility of improving mitochondrial fusion/fission dynamics and motility to correct mitochondrial dysfunction and resulting neurodegeneration in Charcot-Marie-Tooth disease (CMT) and other neuropathies, the clinical utility of reported compounds and relevance of preclinical models are uncertain. Here, we describe motor and sensory neuron dysfunction characteristic of clinical CMT type 2 A in a CRISPR/Casp-engineered Mfn2 Thr105Met (T105M) mutant knock-in mouse. We further demonstrate that daily oral treatment with a novel mitofusin activator derived from the natural product piperine can reverse these neurologic phenotypes. Piperine derivative 8015 promoted mitochondrial fusion and motility in Mfn2-deficient cells in a mitofusin-dependent manner and reversed mitochondrial dysfunction in cultured fibroblasts and reprogrammed motor neurons from a human CMT2A patient carrying the MFN2 T105M mutation. Like previous mitofusin activators, 8015 exhibited stereospecific functionality, but the more active stereoisomer, 8015-P2, is unique in that it has subnanomolar potency and undergoes entero-hepatic recirculation which extends its in vivo half-life. Daily administration of 8015-P2 to Mfn2 T105M knock-in mice for 6 weeks normalized neuromuscular and sensory dysfunction and corrected histological/ultrastructural neurodegeneration and neurogenic myoatrophy. These studies describe a more clinically relevant mouse model of CMT2A and an improved mitofusin activator derived from piperine. We posit that 8015-P2 and other piperine derivatives may benefit CMT2A or other neurodegenerative conditions wherein mitochondrial dysdynamism plays a contributory role.

Glioblastoma (GBM) is a disease of the whole brain, with infiltrative tumor cells protected by an intact blood-brain barrier (BBB). GBM has a poor prognosis despite aggressive treatment, in part due to the lack of adequate drug permeability at the BBB. Standard of care GBM therapies include radiation and cytotoxic chemotherapy that lead to DNA damage. Subsequent activation of DNA damage response (DDR) pathways can induce resistance. Various DDR inhibitors, targeting the key regulators of these pathways such as ataxia telangiectasia mutated and Rad3-related (ATR), are being explored as radio- and chemosensitizers. Elimusertib, a novel ATR kinase inhibitor, can prevent repair of damaged DNA, increasing efficacy of DNA-damaging cytotoxic therapies. Robust synergy was observed in vitro when elimusertib was combined with the DNA-damaging agent temozolomide; however, we did not observe improvement with this combination in in vivo efficacy studies in GBM orthotopic tumor-bearing mice. This in vitro–in vivo disconnect was explored to understand factors influencing central nervous system (CNS) distribution of elimusertib and reasons for lack of efficacy. We observed that elimusertib is rapidly cleared from systemic circulation in mice and would not maintain adequate exposure in the CNS for efficacious combination therapy with temozolomide. CNS distribution of elimusertib is partially limited by P-glycoprotein efflux at the BBB, and high binding to CNS tissues leads to low levels of pharmacologically active (unbound) drug in the brain. Acknowledging the potential for interspecies differences in pharmacokinetics, these data suggest that clinical translation of elimusertib in combination with temozolomide for treatment of GBM may be limited.

Previous studies demonstrated that sigma receptor (R) antagonists alone fail to alter cocaine self-administration despite blocking various other effects of cocaine. However, R antagonists when combined with dopamine transporter (DAT) inhibitors substantially decrease cocaine self-administration. To better understand the effects of this combination, the present study examined the effects of R antagonist and DAT inhibitor combinations in male rats discriminating cocaine (10 mg/kg, i.p.) from saline injections. The DAT inhibitors alone [(–)-2-β-carbomethoxy-3-β-(4-fluorophenyl)tropane 1,5-naphthalenedisulfonate monohydrate (WIN 35,428) and methylphenidate] at low (0.1-mg/kg) doses that were minimally active failed to shift the dose-effect function for discriminative-stimulus effects of cocaine to the left more than 2-fold. At 0.32 mg/kg the DAT inhibitors alone shifted the cocaine dose-effect function leftward 24- or 6.6-fold, respectively. The R antagonists (BD1008, BD1047, and BD1063) failed to fully substitute for cocaine, although BD1008 and BD1047 substituted partially. At 10 mg/kg, BD1008, BD1047, or BD1063 alone shifted the cocaine dose-effect function leftward less than 6.0-fold. In combination with 0.1 mg/kg WIN 35,428, the 10 mg/kg doses of R antagonists shifted the cocaine dose-effect function from 12.3- to 36.7-fold leftward, and with 0.32 mg/kg WIN 35,428 from 14.3- to 440-fold leftward. In combination with 0.1 mg/kg methylphenidate, those R antagonist doses shifted the cocaine dose-effect function from 5.5- to 55.0-fold leftward, and with 0.32 mg/kg methylphenidate from 10.5- to 48.1-fold leftward. The present results suggest that dual DAT/R inhibition produces agonist-like subjective effects that may promote decreases in self-administration obtained in previous studies.

Although acute inflammation serves essential functions in maintaining tissue homeostasis, chronic inflammation is causally linked to many diseases. Macrophages are a major cell type that orchestrates inflammatory processes. During inflammation, macrophages undergo polarization and activation, thereby mobilizing pro-inflammatory and anti-inflammatory transcriptional programs that regulate ensuing macrophage functions. Fatty acid binding protein 5 (FABP5) is a lipid chaperone highly expressed in macrophages. FABP5 deletion is implicated in driving macrophages toward an anti-inflammatory phenotype, yet signaling pathways regulated by macrophage-FABP5 have not been systematically profiled. We leveraged proteomic and phosphoproteomic approaches to characterize pathways modulated by FABP5 in M1 and M2 polarized bone marrow-derived macrophages (BMDMs). Stable isotope labeling by amino acids-based analysis of M1 and M2 polarized wild-type and FABP5 knockout BMDMs revealed numerous differentially regulated proteins and phosphoproteins. FABP5 deletion impacted downstream pathways associated with inflammation, cytokine production, oxidative stress, and kinase activity. Toll-like receptor 2 (TLR2) emerged as a novel target of FABP5 and pharmacological FABP5 inhibition blunted TLR2-mediated activation of downstream pathways, ascribing a novel role for FABP5 in TLR2 signaling. This study represents a comprehensive characterization of the impact of FABP5 deletion on the proteomic and phosphoproteomic landscape of M1 and M2 polarized BMDMs. Loss of FABP5 altered pathways implicated in inflammatory responses, macrophage function, and TLR2 signaling. This work provides a foundation for future studies seeking to investigate the therapeutic potential of FABP5 inhibition in pathophysiological states resulting from dysregulated inflammatory signaling.

Cannabinoid and opioid receptor activities can be modulated by a variety of post-translational mechanisms including the formation of interacting complexes. This study examines the involvement of endogenous and exogenous chaperones in modulating the abundance and activity of cannabinoid CB₁ receptor (CB₁R), opioid receptor (DOR), and CB₁R-DOR interacting complexes. Focusing on endogenous protein chaperones, namely receptor transporter proteins (RTPs), we examined relative mRNA expression in the mouse spinal cord and found RTP4 to be expressed at higher levels compared with other RTPs. Next, we assessed the effect of RTP4 on receptor abundance by manipulating RTP4 expression in cell lines. Overexpression of RTP4 causes an increase and knock-down causes a decrease in the levels of CB₁R, DOR, and CB₁R-DOR interacting complexes; this is accompanied by parallel changes in signaling. The ability of small molecule lipophilic ligands to function as exogenous chaperones was examined using receptor-selective antagonists. Long-term treatment leads to increases in receptor abundance and activity with no changes in mRNA supporting a role as pharmacological chaperones. Finally, the effect of cannabidiol (CBD), a small molecule ligand and a major active component of cannabis, on receptor abundance and activity in mice was examined. We find that CBD administration leads to increases in receptor abundance and activity in mouse spinal cord. Together, these results highlight a role for chaperones (proteins and small molecules) in modulating levels and activity of CB₁R, DOR, and their interacting complexes potentially through mechanisms including receptor maturation and trafficking.

Endocannabinoids, which are present throughout the central nervous system (CNS), can activate cannabinoid receptors 1 and 2 (CB1 and CB2). CB1 and CB2 agonists exhibit broad anti-inflammatory properties, suggesting their potential to treat inflammatory diseases. However, careful evaluation of abuse potential is necessary. This study evaluated the abuse potential of lenabasum, a selective CB2 receptor agonist in participants (n = 56) endorsing recreational cannabis use. Three doses of lenabasum (20, 60, and 120 mg) were compared with placebo and nabilone (3 and 6 mg). The primary endpoint was the peak effect (E_max) on a bipolar Drug Liking visual analog scale (VAS). Secondary VAS and pharmacokinetic (PK) endpoints and adverse events were assessed. Lenabasum was safe and well tolerated. Compared with placebo, a 20-mg dose of lenabasum did not increase ratings of Drug Liking and had no distinguishable effect on other VAS endpoints. Dose-dependent increases in ratings of Drug Liking were observed with 60 and 120 mg lenabasum. Drug Liking and all other VAS outcomes were greatest for nabilone 3 mg and 6 mg, a medication currently approved by the US Food and Drug Administration (FDA). At a target therapeutic dose (20 mg), lenabasum did not elicit subjective ratings of Drug Liking. However, supratherapeutic doses of lenabasum (60 and 120 mg) did elicit subjective ratings of Drug Liking compared with placebo. Although both doses of lenabasum were associated with lower ratings of Drug Liking compared with 3 mg and 6 mg nabilone, lenabasum does have abuse potential and should be used cautiously in clinical settings.

Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of chemotherapy treatment, routinely manifesting as increased pain sensitivity (allodynia) in distal extremities. Despite its prevalence, effective treatment options are limited. Cannabinoids are increasingly being evaluated for their ability to treat chronic pain conditions, including CIPN. While previous studies have revealed sex differences in cannabinoid-mediated antinociception in acute and chronic pain models, there is a paucity of studies addressing potential sex differences in the response of CIPN to cannabinoid treatment. Therefore, we evaluated the long-term antiallodynic efficacy of cannabinoid receptor type 1 (CB₁)-selective, cannabinoid receptor type 2 (CB₂)-selective, and CB₁/CB₂ mixed agonists in the cisplatin CIPN model, using both male and female mice. CB₁ selective agonism was observed to have sex differences in the development of tolerance to antiallodynic effects, with females developing tolerance more rapidly than males, while the antiallodynic effects of selective CB₂ agonism lacked tolerance development. Compound-specific changes to the female estrous cycle and female plasma estradiol levels were noted, with CB₁ selective agonism decreasing plasma estradiol while CB₂ selective agonism increased plasma estradiol. Chronic administration of a mixed CB₁/CB₂ agonist resulted in increased mRNA expression of proinflammatory cytokines and endocannabinoid regulatory enzymes in female spinal cord tissue. Ovarian tissue was noted to have proinflammatory cytokine mRNA expression following administration of a CB₂ acting compound while selective CB₁ agonism resulted in decreased proinflammatory cytokines and endocannabinoid regulatory enzymes in testes. These results support the need for further investigation into the role of sex and sex hormones signaling in pain and cannabinoid-mediated antinociceptive effects.

Oxidative stress, fibrosis, and inflammasome activation from advanced glycation end product (AGE)–receptor of advanced glycation end product (RAGE) interaction contribute to diabetic cardiomyopathy (DCM) formation and progression. Our study revealed the impact of β-caryophyllene (BCP) on activating cannabinoid type 2 receptors (CB2Rs) against diabetic complication, mainly cardiomyopathy and investigated the underlying cell signaling pathways in mice. The murine model of DCM was developed by feeding a high-fat diet with streptozotocin injections. After the development of diabetes, the animals received a 12-week oral BCP treatment at a dose of 50 mg/kg/body weight. BCP treatment showed significant improvement in glucose tolerance and insulin resistance and enhanced serum insulin levels in diabetic animals. BCP treatment effectively reversed the heart remodeling and restored the phosphorylated troponin I and sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a expression. Ultrastructural examination showed reduced myocardial cell injury in DCM mice treated with BCP. The preserved myocytes were found to be associated with reduced expression of AGE/RAGE in DCM mice hearts. BCP treatment mitigated oxidative stress by inhibiting expression of NADPH oxidase 4 and activating phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/nuclear factor erythroid 2–related factor 2 (Nrf2) signaling. Also, BCP suppressed cardiac fibrosis and endothelial-to-mesenchymal transition in DCM mice by inhibiting transforming growth factor β (TGF-β)/suppressor of mothers against decapentaplegic (Smad) signaling. Further, BCP treatment suppressed nucleotide-binding domain, leucine-rich–containing family, pyrin domain–containing-3 (NLRP3) inflammasome activation in DCM mice and alleviated cellular injury to the pancreatic tissues evidenced by significant elevation of the number of insulin-positive cells. To demonstrate a CB2R-dependent mechanism of BCP, another group of DCM mice were pretreated with AM630, a CB2R antagonist. AM630 was observed to abrogate the beneficial effects of BCP in DCM mice. Taken together, BCP demonstrated the potential to protect the myocardium and pancreas of DCM mice mediating CB2R-dependent mechanisms.

Neuropathic pain is a form of chronic pain that develops because of damage to the nervous system. Treatment of neuropathic pain is often incompletely effective, and most available therapeutics have only moderate efficacy and present side effects that limit their use. Opioids are commonly prescribed for the management of neuropathic pain despite equivocal results in clinical studies and significant abuse potential. Thus, neuropathic pain represents an area of critical unmet medical need, and novel classes of therapeutics with improved efficacy and safety profiles are urgently needed. The cannabidiol structural analog and novel antagonist of GPR55, KLS-13019, was screened in rat models of neuropathic pain. Tactile sensitivity associated with chemotherapy exposure was induced in rats with once-daily 1-mg/kg paclitaxel injections for 4 days or 5 mg/kg oxaliplatin every third day for 1 week. Rats were then administered KLS-13019 or comparator drugs on day 7 in an acute dosing paradigm or days 7–10 in a chronic dosing paradigm, and mechanical or cold allodynia was assessed. Allodynia was reversed in a dose-dependent manner in the rats treated with KLS-13019, with the highest dose reverting the response to prepaclitaxel injection baseline levels with both intraperitoneal and oral administration after acute dosing. In the chronic dosing paradigm, four consecutive doses of KLS-13019 completely reversed allodynia for the duration of the phenotype in control animals. Additionally, coadministration of KLS-13019 with paclitaxel prevented the allodynic phenotype from developing. Together, these data suggest that KLS-13019 represents a potential new drug for the treatment of neuropathic pain.

Patients with arthritis report using cannabis for pain management, and the major cannabinoid delta-9-tetrahydrocannabinol (⁹-THC) has anti-inflammatory properties, yet the effects of minor cannabinoids on arthritis are largely unknown. The goal of the present study was to determine the antiarthritic potential of the minor cannabinoid delta-8-tetrahydrocannabinol (⁸-THC) using the collagen-induced arthritis (CIA) mouse model. Adult male DBA/1J mice were immunized and boosted 21 days later with an emulsion of collagen and complete Freund’s adjuvant. Beginning on the day of the booster, mice were administered twice-daily injections of ⁸-THC (3 or 30 mg/kg), the steroid dexamethasone (2 mg/kg), or vehicle for two weeks. Dorsal-ventral paw thickness and qualitative measures of arthritis were recorded daily, and latency to fall from an inverted grid was measured on alternating days, to determine arthritis severity and functional impairment. On the final day of testing, spontaneous wire-climbing behavior and temperature preference in a thermal gradient ring were measured to assess CIA-depressed behavior. The ⁸-THC treatment (30 mg/kg) reduced paw swelling and qualitative signs of arthritis. ⁸-THC also blocked CIA-depressed climbing and CIA-induced preference for a heated floor without producing locomotor effects but did not affect latency to fall from a wire grid. In alignment with the morphologic and behavioral assessments in vivo, histology revealed that ⁸-THC reduced synovial inflammation, proteoglycan loss and cartilage and bone erosion in the foot joints in a dose-dependent manner. Together, these findings suggest that ⁸-THC not only blocked morphologic changes but also prevented functional loss caused by collagen-induced arthritis.

Chronic pain conditions affect nearly 20% of the population in the United States. Current medical interventions, such as opioid drugs, are effective at relieving pain but are accompanied by many undesirable side effects. This is one reason increased numbers of chronic pain patients have been turning to Cannabis for pain management. Cannabis contains many bioactive chemical compounds; however, current research looking into lesser-studied minor cannabinoids in Cannabis lacks uniformity between experimental groups and/or excludes female mice from investigation. This makes it challenging to draw conclusions between experiments done with different minor cannabinoid compounds between laboratories or parse out potential sex differences that could be present. We chose five minor cannabinoids found in lower quantities within Cannabis: cannabinol (CBN), cannabidivarin (CBDV), cannabigerol (CBG), 8-tetrahydrocannabinol (8-THC), and 9-tetrahydrocannabivarin (THCV). These compounds were then tested for their cannabimimetic and pain-relieving behaviors in a cannabinoid tetrad assay and a chemotherapy-induced peripheral neuropathy (CIPN) pain model in male and female CD-1 mice. We found that the minor cannabinoids we tested differed in the cannabimimetic behaviors evoked, as well as the extent. We found that CBN, CBG, and high-dose 8-THC evoked some tetrad behaviors in both sexes, while THCV and low-dose 8-THC exhibited cannabimimetic tetrad behaviors only in females. Only CBN efficaciously relieved CIPN pain, which contrasts with reports from other researchers. Together these findings provide further clarity to the pharmacology of minor cannabinoids and suggest further investigation into their mechanism and therapeutic potential.

There is a growing interest in the use of medicinal plants to treat a variety of diseases, and one of the most commonly used medicinal plants globally is Cannabis sativa. The two most abundant cannabinoids (⁹-tetrahydrocannabinol and cannabidiol) have been governmentally approved to treat selected medical conditions; however, the plant produces over 100 cannabinoids, including cannabichromene (CBC). Although the cannabinoids share a common precursor molecule, cannabigerol, they are structurally and pharmacologically unique. These differences may engender differing therapeutic potentials. In this review, we will examine what is currently known about CBC with regards to pharmacodynamics, pharmacokinetics, and receptor profile. We will also discuss the therapeutic areas that have been examined for this cannabinoid, notably antinociceptive, antibacterial, and anti-seizure activities. Finally, we will discuss areas where new research is needed and potential novel medicinal applications for CBC.

⁹-Tetrahydrocannabinol (THC) is a psychoactive phytocannabinoid found in the Cannabis sativa plant. THC is primarily metabolized into 11-hydroxy-⁹-tetrahydrocannabinol (11-OH-THC) and 11-nor-9-carboxy-⁹-tetrahydrocannabinol (COOH-THC), which may themselves be psychoactive. There is very little research-based evidence concerning the pharmacokinetics and pharmacodynamics of 11-OH-THC as an individual compound. Male C57BL/6 mice were treated with THC or 11-OH-THC via intraperitoneal injection, tail vein intravenous injection, or oral gavage, and whole-blood compound levels were measured to determine pharmacokinetic parameters [C_max, time to C_max (T_max), elimination half-life, area under the curve, apparent volume of distribution, systemic clearance, terminal rate constant, and absolute bioavailability] while also monitoring changes in catalepsy, body temperature, and nociception. 11-OH-THC achieved a T_max at 30 minutes for all routes of administration. The maximum concentration at 30 minutes was not different between intravenous and intraperitoneal routes, but the oral gavage C_max was significantly lower. THC had a 10-minute time to the maximum concentration, which was the first blood collection time point, for intravenous and intraperitoneal and 60 minutes for oral gavage, with a lower C_max for intraperitoneal and oral gavage compared with intravenous. When accounting for circulating compound levels and ED₅₀ responses, these data suggest that 11-OH-THC was 153% as active as THC in the tail-flick test of nociception and 78% as active as THC for catalepsy. Therefore, 11-OH-THC displayed equal or greater activity than the parent compound THC, even when accounting for pharmacokinetic differences. Thus, the THC metabolite 11-OH-THC likely plays a critical role in the bioactivity of cannabis; understanding its activity when administered directly will aid in the interpretation of future animal and human studies.

The consumption of ⁹-tetrahydrocannabinol (THC)- or cannabis-containing edibles has increased in recent years; however, the behavioral and neural circuit effects of such consumption remain unknown, especially in the context of ingestion of higher doses resulting in cannabis intoxication. We examined the neural and behavioral effects of acute high-dose edible cannabis consumption (AHDECC). Sprague-Dawley rats (six males, seven females) were implanted with electrodes in the prefrontal cortex (PFC), dorsal hippocampus (dHipp), cingulate cortex (Cg), and nucleus accumbens (NAc). Rats were provided access to a mixture of Nutella (6 g/kg) and THC-containing cannabis oil (20 mg/kg) for 10 minutes, during which they voluntarily consumed all of the provided Nutella and THC mixture. Cannabis tetrad and neural oscillations were examined 2, 4, 8, and 24 hours after exposure. In another cohort (16 males, 15 females), we examined the effects of AHDECC on learning and prepulse inhibition and serum and brain THC and 11-hydroxy-THC concentrations. AHDECC resulted in higher brain and serum THC and 11-hydroxy-THC levels in female rats over 24 hours. AHDECC also produced: 1) Cg, dHipp, and NAc gamma power suppression, with the suppression being greater in female rats, in a time-dependent manner; 2) hypolocomotion, hypothermia, and antinociception in a time-dependent manner; and 3) learning and prepulse inhibition impairments. Additionally, most neural activity and behavior changes appear 2 hours after ingestion, suggesting that interventions around this time might be effective in reversing/reducing the effects of AHDECC.

People with sickle cell disease (SCD) often experience chronic pain as well as unpredictable episodes of acute pain, which significantly affects their quality of life and life expectancy. Current treatment strategies for SCD-associated pain primarily rely on opioid analgesics, which have limited efficacy and cause serious adverse effects. Cannabis has emerged as a potential alternative, yet its efficacy remains uncertain. In this study, we investigated the antinociceptive effects of ⁹-tetrahydrocannabinol (THC), cannabis’ intoxicating constituent, in male HbSS mice, which express >99% human sickle hemoglobin, and male HbAA mice, which express normal human hemoglobin A, as a control. Acute THC administration (0.1–3 mg/kg^–1, i.p.) dose-dependently reduced mechanical and cold hypersensitivity in human sickle hemoglobin (HbSS) but not human normal hemoglobin A (HbAA) mice. In the tail-flick assay, THC (1 and 3 mg/kg^–1, i.p.) produced substantial antinociceptive effects in HbSS mice. By contrast, THC (1 mg/kg^–1, i.p.) did not alter anxiety-like behavior (elevated plus maze) or long-term memory (24-hour novel object recognition). Subchronic THC treatment (1 and 3 mg/kg^–1, i.p.) provided sustained relief of mechanical hypersensitivity but led to tolerance in cold hypersensitivity in HbSS mice. Together, the findings identify THC as a possible therapeutic option for the management of chronic pain in SCD. Further research is warranted to elucidate its mechanism of action and possible interaction with other cannabis constituents.

Targeting the endocannabinoid (eCB) signaling system for pain relief is an important treatment option that is only now beginning to be mechanistically explored. In this review, we focus on two recently appreciated cannabinoid-based targeting strategies, treatments with cannabidiol (CBD) and α/β-hydrolase domain containing 6 (ABHD6) inhibitors, which have the exciting potential to produce pain relief through distinct mechanisms of action and without intoxication. We review evidence on plant-derived cannabinoids for pain, with an emphasis on CBD and its multiple molecular targets expressed in pain pathways. We also discuss the function of eCB signaling in regulating pain responses and the therapeutic promises of inhibitors targeting ABHD6, a 2-arachidonoylglycerol (2-AG)-hydrolyzing enzyme. Finally, we discuss how the novel cannabinoid biosensor GRAB_eCB2.0 may be leveraged to enable the discovery of targets modulated by cannabinoids at a circuit-specific level.

The National Center for Complementary and Integrative Health (NCCIH), which is part of the US National Institutes of Health (NIH), has a broad interest in studying the biologic activities of natural products, especially those for which compelling evidence from preclinical research suggests biologic activities that may be beneficial to health or have a potential role in disease treatment, as well as products used extensively by the American public. As of 2023, use of cannabis for medical purposes is legal in 38 states and Washington, D.C. Such use continues to climb generally without sufficient knowledge regarding risks and benefits. In keeping with NCCIH’s natural product research priorities and recognizing this gap in knowledge, NCCIH formally launched a research program in 2019 to expand research on the possible benefits for pain management of certain substances found in cannabis: minor cannabinoids and terpenes. This Viewpoint provides additional details and the rationale for this research priority at NCCIH. In addition, NCCIH’s efforts and initiatives to facilitate and coordinate an NIH research agenda focused on cannabis and cannabinoid research are described.

Cannabis and its products have been used for centuries for both medicinal and recreational purposes. The recent widespread legalization of cannabis has vastly expanded its use in the United States across all demographics except for adolescents. Meanwhile, decades of research have advanced our knowledge of cannabis pharmacology and particularly of the endocannabinoid system with which the components of cannabis interact. This research has revealed multiple targets and approaches for manipulating the system for therapeutic use and to ameliorate cannabis toxicity or cannabis use disorder. Research has also led to new questions that underscore the potential risks of its widespread use, particularly the enduring consequences of exposure during critical windows of brain development or for consumption of large daily doses of cannabis with high content ⁹-tetrahydrocannabinol. This article highlights current neuroscience research on cannabis that has shed light on therapeutic opportunities and potential adverse consequences of misuse and points to gaps in knowledge that can guide future research.

Low-efficacy mu opioid receptor (MOR) agonists may serve as novel candidate analgesics with improved safety relative to high-efficacy opioids. This study used a recently validated assay of pain-depressed behavior in mice to evaluate a novel series of MOR-selective C9-substituted phenylmorphan opioids with graded MOR efficacies. Intraperitoneal injection of dilute lactic acid (IP acid) served as a noxious stimulus to depress locomotor activity by mice in an activity chamber composed of two compartments connected by an obstructed door. Behavioral measures included (1) crosses between compartments (vertical activity over the obstruction) and (2) movement counts quantified as photobeam breaks summed across compartments (horizontal activity). Each drug was tested alone and as a pretreatment to IP acid. A charcoal-meal test and whole-body-plethysmography assessment of breathing in 5% CO₂ were also used to assess gastrointestinal (GI) inhibition and respiratory depression, respectively. IP acid produced a concentration-dependent depression in crosses and movement that was optimally alleviated by intermediate- to low-efficacy phenylmorphans with sufficient efficacy to produce analgesia with minimal locomotor disruption. Follow-up studies with two low-efficacy phenylmorphans (JL-2-39 and DC-1-76.1) indicated that both drugs produced naltrexone-reversible antinociception with a rapid onset and a duration of ~1 h. Potency of both drugs increased when behavior was depressed by a lower IP-acid concentration, and neither drug alleviated behavioral depression by a non-pain stimulus (IP lithium chloride). Both drugs produced weaker GI inhibition and respiratory depression than fentanyl and attenuated fentanyl-induced GI inhibition and respiratory depression. Results support further consideration of selective, low-efficacy MOR agonists as candidate analgesics.