Interrelated involvement of the endocannabinoid/endovanilloid (TRPV1) systems and epigenetic processes in anxiety- and working memory impairment-related behavioural effects of nicotine as a stressor.

The addictive use of nicotine contained in tobacco is associated with stressor-like emotional and cognitive effects such as anxiety and working memory impairment, and the involvement of epigenetic mechanisms such as histone acetylation has recently been reported. Although the precise nature of behavioural plasticity remains unclear, both anxiogenic- and working memory impairment-like effects were observed in the present experimental model of mice treated with repeated subcutaneous nicotine and/or immobilization stress, and these effects were commonly attenuated by the histone deacetylase (HDAC) inhibitors that induce histone acetylation. Such HDAC inhibitor-induced resilience was mimicked by ligands for the endocannabinoid (ECB) system, a neurotransmitter system that is closely associated with nicotine-induced addiction-related behaviours: the anxiogenic-like effects were mitigated by the cannabinoid type 1 (CB1) agonist arachidonylcyclopropylamide (ACPA), whereas the working memory impairment-like effects were mitigated by the CB1 antagonist SR 141716A. Moreover, the effects of the HDAC inhibitors were also mimicked by ligands for the endovanilloid (transient receptor potential vanilloid 1 [TRPV1]) system, a system that shares common characteristics with the ECB system: the anxiogenic-like effects were mitigated by the TRPV1 antagonist capsazepine, whereas the working memory impairment-like effects were mitigated by the TRPV1 agonist olvanil. Notably, the HDAC inhibitor-induced anxiolytic-like effects were attenuated by SR 141716A, which were further counteracted by capsazepine, whereas the working memory improvement-like effects were attenuated by capsazepine, which were further counteracted by SR 141716A. These results suggest the contribution of interrelated control of the ECB/TRPV1 systems and epigenetic processes such as histone acetylation to novel therapeutic approaches.

Comparison of the effects of axillary brachial plexus block, inhalation anesthesia, and total intravenous anesthesia on tourniquet-induced ischemia-reperfusion injury in upper extremity surgery.

BACKGROUND: Post-ischemia reperfusion can lead to oxidative stress and an increase in oxidative markers. Employing preventive strategies and antioxidant agents may help mitigate ischemia-reperfusion injury (IRI). The use of a tourniquet in extremity surgery has been associated with IRI. This study aims to investigate the impact of three different approaches- brachial plexus block, total intravenous anesthesia (TIVA), and inhalation anesthesia-on IRI during upper extremity surgery using a tourniquet. METHODS: Patients aged 18 to 45 with American Society of Anesthesiologists (ASA) I-II scores were randomly assigned to one of three groups: Group A received an axillary block with bupivacaine; Group I underwent inhalation anesthesia with sevoflurane; and Group T received TIVA with propofol and remifentanil infusion. Blood samples were collected to measure glucose, lactate, total anti-oxidant status (TAS), total oxidant status (TOS), and ischemia-modified albumin (IMA) levels at various time points: before anesthesia (t1), 1 minute before tourniquet release (t2), 20 minutes after tourniquet release (t3), and 4 hours after tourniquet release (t4). RESULTS: In Group I, lactate levels at t3, and glucose levels at t2 and t3, were higher compared to the other groups. Group A exhibited lower IMA levels at t2, t3, and t4 than the other groups. Additionally, Group I had lower IMA levels at t2, t3, and t4 compared to Group T. TAS levels were higher in Group I at t2, t3, and t4 compared to the other groups. TOS levels at t2 and t3 were lower in Group A than in Group I. CONCLUSION: Axillary anesthesia results in a sympathetic block, promoting better perfusion of the upper extremity. This study demonstrated lower levels of oxidative stress markers with axillary plexus block. Therefore, these results suggest that the axillary block has the potential to mitigate IRI.

Comparison of efficacy and safety of tofacitinib and azathioprine in patients with alopecia areata and variants: a double-blind, randomized controlled trial.

BACKGROUND: Alopecia areata (AA) is an autoimmune pathology manifested by loss of hair. OBJECTIVE: To evaluate and compare the efficacy and safety of tofacitinib and azathioprine in patients with AA and variants. METHODS: In this double-blind randomized controlled trail (RCT) carried out at the Department of Dermatology, Medical Teaching Institute-Lady Reading Hospital (MTI-LRH), Peshawar, Pakistan, patients aged ≥ 12 years diagnosed with AA, alopecia totalis (AT) or alopecia universalis (AU) with minimum 50% scalp hair loss for a period ≥ 06 years were included. Patients were randomly assigned to receive oral tofacitinib 5 mg twice daily (Group I) or oral azathioprine 2 mg/kg body weight once daily (Group II). The primary endpoint was Severity of Alopecia Tool (SALT) score, evaluated at baseline and 06 months follow-up. Safety was consistently assessed during the study. RESULTS: A total of 104 patients underwent random allocation into either the tofacitinib group (n = 52) or the azathioprine group (n = 52). The mean (SD) age of patients was 20.23 (7.14) years and 22.26 (8.07) years, while the mean (SD) disease duration was 6.59 (4.01) years and 7.98 (4.40) years in in Group I and II, respectively. Overall, 40 (38.5%) patients were adolescents while 70 (67.3%) were male. 52 (50%) had AA, 37 (35.5%) had AT and 15 (14.5%) had AU. Mean baseline SALT score in tofacitinib group was 91.02 ± 10.21 and azathioprine group was 91.02 ± 10.63, which at 06 months follow-up improved to 14.1 ± 24.6 and 63.9 ± 33.9, respectively (difference, 11.5 points; 95% confidence interval, 38.3-61.3, p < 0.0001). Overall, no major adverse effects and no difference among the minor adverse effects in the two groups (04 adverse events for tofacitinib group and 08 for azathioprine group: p = 0.23) was observed. CONCLUSIONS: Efficacy of tofacitinib was significantly higher than azathioprine, whilst both drugs were well-tolerated in patients with AA and variants.

Nanosuspension-Based Repaglinide Fast-Dissolving Buccal Film for Dissolution Enhancement.

Drug solubility and dissolution remain a significant challenge in pharmaceutical formulations. This study aimed to formulate and evaluate repanglinide (RPG) nanosuspension-based buccal fast-dissolving films (BDFs) for dissolution enhancement. RPG nanosuspension was prepared by the antisolvent-precipitation method using multiple hydrophilic polymers, including soluplus®, polyvinyl alcohol, polyvinyl pyrrolidine, poloxamers, and hydroxyl propyl methyl cellulose. The nanosuspension was then directly loaded into BDFs using the solvent casting technique. Twelve formulas were prepared with a particle size range of 81.6-1389 nm and PDI 0.002-1 for the different polymers. Nanosuspensions prepared with soluplus showed a favored mean particle size of 82.6 ± 3.2 nm. The particles were spherical and non-aggregating, as demonstrated by SEM imaging. FTIR showed no interaction between soluplus and RPG. Faster dissolution occurred for the nanosuspension in comparison with pure RPG (complete release vs 60% within 30 min). The nanosuspension was successfully incorporated into BDFs. The optimum film formula showed 28 s disintegration time, and 97.3% RPG released within 10 min. Ex-vivo permeation profiles revealed improved RPG nanosuspension permeation with the cumulative amount of RPG permeated is103.4% ± 10.1 and a flux of 0.00275 mg/cm2/min compared to 39.3% ± 9.57 and a flux of 0.001058 mg/cm2/min for pure RPG. RPG was successfully formulated into nanosuspension that boosted drug dissolution and permeation. The selection of the ultimate NP formula was driven by optimal particle size, distribution, and drug content. Soluplus NPs were shown to be the successful formulations, which were further incorporated into a buccal film. The film was evaluated for ex-vivo permeation, confirming successful RPG formulation with improved performance compared to pure drugs.

ALINA: Another stepping stone toward a future of LDCT lung cancer screening in never-smokers?

The ALINA trial1 demonstrated that 2 years of adjuvant alectinib achieved statistically significantly improved 2-year overall and central nervous system (CNS) disease-free survival over platinum-doublet chemotherapy in resected early-stage (IB ≥ 4 cm to IIIA) ALK+ non-small cell lung cancer (NSCLC). Identifying early-stage ALK+ NSCLC patients (60% were never-smokers in the ALINA trial) may require low-dose computed tomography (LDCT) lung cancer screening in never-smokers.

Tofacitinib Regulates Endostatin via Effects on CD147 and Cathepsin S.

Angiogenesis is critical for rheumatoid arthritis (RA) progression. The effects of tofacitinib, a JAK-STAT inhibitor used for RA treatment, on angiogenesis in RA are unclear. We, therefore, evaluated the levels of angiogenic factors in two systems of a human co-culture of fibroblast (HT1080) and monocytic (U937) cell lines treated with tofacitinib and in serum samples from RA patients before and after six months of tofacitinib treatment. Tofacitinib reduced CD147 levels, matrix metalloproteinase-9 (MMP-9) activity, and angiogenic potential but increased endostatin levels and secreted proteasome 20S activity. In vitro, tofacitinib did not change CD147 mRNA but increased miR-146a-5p expression and reduced STAT3 phosphorylation. We recently showed that CD147 regulates the ability of MMP-9 and secreted proteasome 20S to cleave collagen XVIIIA into endostatin. We show here that tofacitinib-enhanced endostatin levels are mediated by CD147, as CD147-siRNA or an anti-CD147 antibody blocked proteasome 20S activity. The correlation between CD147 and different disease severity scores supported this role. Lastly, tofacitinib reduced endostatin' s degradation by inhibiting cathepsin S activity and recombinant cathepsin S reversed this in both systems. Thus, tofacitinib inhibits angiogenesis by reducing pro-angiogenic factors and enhancing the anti-angiogenic factor endostatin in a dual effect mediated partly through CD147 and partly through cathepsin S.

Tofacitinib Treatment Suppresses CD4+ T-Cell Activation and Th1 Response, Contributing to Protection against Staphylococcal Toxic Shock.

Staphylococcal toxic shock syndrome (STSS) is a rare, yet potentially fatal disease caused by Staphylococcus aureus (S. aureus) enterotoxins, known as superantigens, which trigger an intense immune response. Our previous study demonstrated the protective effect of tofacitinib against murine toxin-induced shock and a beneficial effect against S. aureus sepsis. In the current study, we examined the effects of tofacitinib on T-cell response in peripheral blood using a mouse model of enterotoxin-induced shock. Our data revealed that tofacitinib suppresses the activation of both CD4+ and CD8+ T cells in peripheral blood. Furthermore, both gene and protein levels of Th1 cytokines were downregulated by tofacitinib treatment in mice with enterotoxin-induced shock. Importantly, we demonstrated that CD4+ cells, but not CD8+ cells, are pathogenic in mice with enterotoxin-induced shock. In conclusion, our findings suggest that tofacitinib treatment suppresses CD4+ T-cell activation and Th1 response, thereby aiding in protection against staphylococcal toxic shock in mice. This insight may guide the future development of novel therapies for STSS.

Inhibition of M. tuberculosis and human ATP synthase by BDQ and TBAJ-587.

Bedaquiline (BDQ), a first-in-class diarylquinoline anti-tuberculosis drug, and its analogue, TBAJ-587, prevent the growth and proliferation of Mycobacterium tuberculosis by inhibiting ATP synthase1,2. However, BDQ also inhibits human ATP synthase3. At present, how these compounds interact with either M. tuberculosis ATP synthase or human ATP synthase is unclear. Here we present cryogenic electron microscopy structures of M. tuberculosis ATP synthase with and without BDQ and TBAJ-587 bound, and human ATP synthase bound to BDQ. The two inhibitors interact with subunit a and the c-ring at the leading site, c-only sites and lagging site in M. tuberculosis ATP synthase, showing that BDQ and TBAJ-587 have similar modes of action. The quinolinyl and dimethylamino units of the compounds make extensive contacts with the protein. The structure of human ATP synthase in complex with BDQ reveals that the BDQ-binding site is similar to that observed for the leading site in M. tuberculosis ATP synthase, and that the quinolinyl unit also interacts extensively with the human enzyme. This study will improve researchers' understanding of the similarities and differences between human ATP synthase and M. tuberculosis ATP synthase in terms of the mode of BDQ binding, and will allow the rational design of novel diarylquinolines as anti-tuberculosis drugs.

Morpholine, Piperazine, and Piperidine Derivatives as Antidiabetic Agents.

Diabetes mellitus is a severe endocrine disease that affects more and more people every year. Modern medical chemistry sets itself the task of finding effective and safe drugs against diabetes. This review provides an overview of potential antidiabetic drugs based on three heterocyclic compounds, namely morpholine, piperazine, and piperidine. Studies have shown that compounds containing their moieties can be quite effective in vitro and in vivo for the treatment of diabetes and its consequences.

Inhibition of Monoamine Oxidases by Pyridazinobenzylpiperidine Derivatives.

Monoamine oxidase inhibitors (MAOIs) have been crucial in the search for anti-neurodegenerative medications and continued to be a vital source of molecular and mechanistic diversity. Therefore, the search for selective MAOIs is one of the main areas of current drug development. To increase the effectiveness and safety of treating Parkinson's disease, new scaffolds for reversible MAO-B inhibitors are being developed. A total of 24 pyridazinobenzylpiperidine derivatives were synthesized and evaluated for MAO. Most of the compounds showed a higher inhibition of MAO-B than of MAO-A. Compound S5 most potently inhibited MAO-B with an IC50 value of 0.203 µM, followed by S16 (IC50 = 0.979 µM). In contrast, all compounds showed weak MAO-A inhibition. Among them, S15 most potently inhibited MAO-A with an IC50 value of 3.691 µM, followed by S5 (IC50 = 3.857 µM). Compound S5 had the highest selectivity index (SI) value of 19.04 for MAO-B compared with MAO-A. Compound S5 (3-Cl) showed greater MAO-B inhibition than the other derivatives with substituents of -Cl > -OCH3 > -F > -CN > -CH3 > -Br at the 3-position. However, the 2- and 4-position showed low MAO-B inhibition, except S16 (2-CN). In addition, compounds containing two or more substituents exhibited low MAO-B inhibition. In the kinetic study, the Ki values of S5 and S16 for MAO-B were 0.155 ± 0.050 and 0.721 ± 0.074 µM, respectively, with competitive reversible-type inhibition. Additionally, in the PAMPA, both lead compounds demonstrated blood-brain barrier penetration. Furthermore, stability was demonstrated by the 2V5Z-S5 complex by pi-pi stacking with Tyr398 and Tyr326. These results suggest that S5 and S16 are potent, reversible, selective MAO-B inhibitors that can be used as potential agents for the treatment of neurological disorders.

Prior herpes zoster occurrence and high-dose corticosteroids increase herpes zoster risk in rheumatoid arthritis patients receiving janus kinase inhibitors in a retrospective and observational study.

Herpes zoster (HZ) risk is increased in rheumatoid arthritis (RA) patients receiving Janus kinase inhibitors (JAKi) therapy. Identifying and evaluating the risk factors of HZ development in patients receiving JAKi therapy would be clinically helpful. We investigated HZ's incidence rates (IR), identified the risk factors, and further assessed their influence on HZ development in RA patients undergoing JAKi therapy. We retrospectively evaluated 249 RA patients who received JAKi therapy between 2015 and 2023. Data regarding clinical characteristics, HZ reactivation, HZ vaccination status, and concomitant medication use were collected. Among 249 JAKi-treated patients, 44 developed new-onset HZ (tofacitinib, 28/142; baricitinib, 6/35; upadacitinib,10/72), with an IR of 5.11/100patient-years. Multivariate analysis revealed significant predictors of HZ development: a long JAKi exposure period, prior HZ or COVID-19 history, and concomitant high-dose corticosteroids use. The interval between JAKi initiation and HZ development was significantly shorter in patients with prior HZ history than in those without (median, 6.5 months versus 33.5 months, p < 0.001), suggesting "biphasic" emergence of HZ. Only one patient who had experienced an HZ episode while receiving JAKi developed recurrent HZ. None of the seventeen patients immunized with the non-live recombinant zoster vaccine developed HZ. Our JAKi-treated patients had elevated HZ risks, a class effect across different JAKi. A long exposure period, prior history of HZ or COVID-19, and concomitant high-dose corticosteroid treatment may further increase the risk. The emergence of HZ shows a biphasic pattern: early HZ development in patients with prior HZ and late development in those without. Key Points • An increased risk of HZ was observed in Taiwanese RA patients treated with JAKi, presenting as a class effect. • Patients with a long JAKi exposure period, prior history of HZ or COVID-19, and concomitant use of high-dose corticosteroids were at high risk of HZ while receiving JAKi therapy. • The interval between JAKi initiation and HZ occurrence was shorter in patients with prior HZ than in those without, showing "biphasic" emergence.

Feasibility of Indirect Treatment Comparisons Between Niraparib Plus Abiraterone Acetate and Other First-Line Poly ADP-Ribose Polymerase Inhibitor Treatment Regimens for Patients with BRCA1/2 Mutation-Positive Metastatic Castration-Resistant Prostate Cancer.

INTRODUCTION: Poly(ADP-ribose) polymerase inhibitors (PARPi) are a novel option to treat patients with metastatic castration-resistant prostate cancer (mCRPC). Niraparib plus abiraterone acetate and prednisone (AAP) is indicated for BRCA1/2 mutation-positive mCRPC. Niraparib plus AAP demonstrated safety and efficacy in the phase 3 MAGNITUDE trial (NCT03748641). In the absence of head-to-head studies comparing PARPi regimens, the feasibility of conducting indirect treatment comparisons (ITC) to inform decisions for patients with first-line BRCA1/2 mutation-positive mCRPC has been explored. METHODS: A systematic literature review was conducted to identify evidence from randomized controlled trials on relevant comparators to inform the feasibility of conducting ITCs via network meta-analysis (NMA) or population-adjusted indirect comparisons (PAIC). Feasibility was assessed based on network connectivity, data availability in the BRCA1/2 mutation-positive population, and degree of within- and between-study heterogeneity or bias. RESULTS: NMAs between niraparib plus AAP and other PARPi regimens (olaparib monotherapy, olaparib plus AAP, and talazoparib plus enzalutamide) were inappropriate due to the disconnected network, differences in trial populations related to effect modifiers, or imbalances within BRCA1/2 mutation-positive subgroups. The latter issue, coupled with the lack of a common comparator (except for olaparib plus AAP), also rendered anchored PAICs infeasible. Unanchored PAICs were either inappropriate due to lack of population overlap (vs. olaparib monotherapy) or were restricted by unmeasured confounders and small sample size (vs. olaparib plus AAP). PAIC versus talazoparib plus enzalutamide was not possible due to lack of published arm-level baseline characteristics and sufficient efficacy outcome data in the relevant population. CONCLUSION: The current randomized controlled trial evidence network does not permit robust comparisons between niraparib plus AAP and other PARPi regimens for patients with 1L BRCA-positive mCRPC. Decision-makers should scrutinize any ITC results in light of their limitations. Real-world evidence combined with clinical experience should inform treatment recommendations in this indication.

Characterization and Dissolution Mechanism of Low-Molecular-Weight Organic Acids or Inorganic Mesoporous Particle-Based Piperine Amorphous Solid Dispersions.

The objective of the current study is to prepare amorphous solid dispersions (ASDs) containing piperine (PIP) by utilizing organic acid glycyrrhizic acid (GA) and inorganic disordered mesoporous silica 244FP (MSN/244FP) as carriers and to investigate their dissolution mechanism. The physicochemical properties of ASDs were characterized with scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), and differential scanning calorimetry (DSC). Fourier transform infrared spectroscopy (FTIR) and one-dimensional proton nuclear magnetic resonance (1H NMR) studies collectively proved that strong hydrogen-bonding interactions formed between PIP and the carriers in ASDs. Additionally, molecular dynamic (MD) simulation was conducted to simulate and predict the physical stability and dissolution mechanisms of the ASDs. Interestingly, it revealed a significant increase in the dissolution of amorphous PIP in ASDs in in vitro dissolution studies. Rapid dissolution of GA in pH 6.8 medium resulted in the immediate release of PIP drugs into a supersaturated state, acting as a dissolution-control mechanism. This exhibited a high degree of fitting with the pseudo-second-order dynamic model, with an R2 value of 0.9996. Conversely, the silanol groups on the outer surface of the MSN and its porous nanostructures enabled PIP to display a unique two-step drug release curve, indicating a diffusion-controlled mechanism. This curve conformed to the Ritger-Peppas model, with an R2 > 0.9. The results obtained provide a clear evidence of the proposed transition of dissolution mechanism within the same ASD system, induced by changes in the properties of carriers in a solution medium of varying pH levels.

[The efficacy and safety of anlotinib combined with niraparib in treating patients with platinum-resistant recurrent ovarian cancer].

Objectives: To investigate the efficacy and safety of anlotinib combined with niraparib in treating patients with platinum-resistant ovarian cancer. Methods: Thirty-five patients with pathological confirmed platinum-resistant ovarian cancer who experienced progression after receiving at least two lines of standard treatment were eligible. All of them were treated with anlotinib combined with niraparib between September 2019 and October 2021. The primary endpoint was progression-free survival (PFS). The second endpoints included overall survival, objective response rate (ORR), disease control rate (DCR) and safety. Survival analysis was performed using the Kaplan-Meier method and Log-rank test, and influence factor analysis was performed using Cox proportional risk regression models. Results: The best overall response showed that partial response was observed in 14 patients, stable disease was noted within 13 patients, and progressive disease was found in 8 patients. Therefore, the ORR and DCR of these 35 patients were 40.0% (95% CI:22.9%-57.1%) and 77.1% (95% CI:62.9%-91.4%), respectively. The median follow-up duration was 18.9 months (6.9-32.2). The median PFS was 6.5 months (95% CI:5.35-7.66). Multivariate Cox regression analysis for PFS indicated that age, Eastern Cooperative Oncology Group performance status (ECOG PS) score, International Federation of Gynecology and Obstetrics (FIGO) stage, and BRCA mutation status were independent factors influencing PFS (P＜0.05). Additionally, the PFS in patients with BRCA mutation who have never received PARP inhibitor treatment was significantly longer than that in patients without BRCA mutation who have been exposed to prior PARPi treatment (15.0 vs 6.0 month, P=0.029). The most common treatment-related adverse reactions were fatigue (85.7%), hematologic toxic (85.7%) and hypertension (74.3%). There were no treatment-related deaths. Conclusion: Anlotinib combined with niraparib shows a promising efficacy and tolerable safety in platinum-resistant ROC patients.

Direct Multi-Deuterium Labelling of Pirtobrutinib.

Herein, we demonstrate an efficient method for multi-deuterium labelling of pirtobrutinib-a Bruton's tyrosine kinase inhibitor recently approved by the FDA-using a straightforward hydrogen isotope exchange (HIE) reaction. A remarkably high level of deuterium incorporation was achieved using an excess of a Kerr-type iridium catalyst. The key factor in the significant deuterium labelling was the decision to employ a deuterium uniformly labelled solvent, chlorobenzene-d5, at an elevated temperature. Virtually, no d0-d3 species were detected, with only traces of d4-d5 isotopomers (< 5%) observable in the mass spectrum of pirtobrutinib-d8, fulfilling requirements for stable isotope-labelled internal standard. The labelled compound-mainly consisting of isotopomers d6-d9 at 82.4% of the total abundance-was isolated in a high yield (73%) and purity (99%). Noteworthy, fluorine group acting as a directing group was observed for the first time. Significant incorporation of deuterium in ortho-positions, exceeding 87%, was observed. Interestingly, chlorinated solvent used in the HIE reactions was non-specifically deuterated yielding up to 0.42 deuterium per chlorobenzene molecule even at an exceptionally low iridium catalyst loading of 4.17 × 10-2 mol%.

A novel approach with tofacitinib for the management of keratoderma blennorrhagicum in reactive arthritis: a case report.

Reactive arthritis(ReA), a form of arthritis occurring post-infection, manifests with antecedent infection symptoms, arthritis, and extra-articular manifestations, categorizing it as spondyloarthritis. "Keratoderma blennorrhagicum" (characterized by pustular hyperkeratosis on palms and soles, resembling pustular psoriasis) represents the most typical skin manifestation of ReA, occurring in acute or chronic phases. Severe lesions necessitate systemic disease modifying anti-rheumatic drugs (DMARDs) or biologic therapies. This article reports a case of ReA with sacroiliitis and widespread pustular eruptions following a urinary tract infection. Treatment with sulfasalazine and thalidomide significantly improved sacroiliitis, but the skin rash remained persistent and recurring. Subsequent use of adalimumab and secukinumab resulted in worsening skin rash, prompting a switch to tofacitinib, leading to a remarkable improvement in pustular eruptions after 20 days of treatment. This case demonstrates successful application of tofacitinib in treating severe keratoderma blennorrhagicum refractory to conventional DMARDs and biologics, offering insights into JAK inhibition for challenging rheumatic diseases with skin involvement.

Inhibition of 2-AG hydrolysis alleviates posttraumatic headache attributed to mild traumatic brain injury.

BACKGROUND: Posttraumatic headache (PTH) is a common and debilitating symptom following repetitive mild traumatic brain injury (rmTBI), and it mainly resembles a migraine-like phenotype. While modulation of the endocannabinoid system (ECS) is effective in treating TBI and various types of pain including migraine, the role of augmentation of endocannabinoids in treating PTH has not been investigated. METHODS: Repetitive mild TBI was induced in male C57BL/6J mice using the non-invasive close-head impact model of engineered rotational acceleration (CHIMERA). Periorbital allodynia was assessed using von Frey filaments and determined by the "Up-Down" method. Immunofluorescence staining was employed to investigate glial cell activation and calcitonin gene-related peptide (CGRP) expression in the trigeminal ganglion (TG) and trigeminal nucleus caudalis (TNC) of the rmTBI mice. Levels of 2-arachidonoyl glycerol (2-AG), anandamide (AEA), and arachidonic acid (AA) in the TG, medulla (including TNC), and periaqueductal gray (PAG) were measured by mass spectrometry. The therapeutic effect of endocannabinoid modulation on PTH was also assessed. RESULTS: The rmTBI mice exhibited significantly increased cephalic pain hypersensitivity compared to the sham controls. MJN110, a potent and selective inhibitor of the 2-AG hydrolytic enzyme monoacylglycerol lipase (MAGL), dose-dependently attenuated periorbital allodynia in the rmTBI animals. Administration of CGRP at 0.01 mg/kg reinstated periorbital allodynia in the rmTBI animals on days 33 and 45 post-injury but had no effect in the sham and MJN110 treatment groups. Activation of glial cells along with increased production of CGRP in the TG and TNC at 7 and 14 days post-rmTBI were attenuated by MJN110 treatment. The anti-inflammatory and anti-nociceptive effects of MJN110 were partially mediated by cannabinoid receptor activation, and the pain-suppressive effect of MJN110 was completely blocked by co-administration of DO34, an inhibitor of 2-AG synthase. The levels of 2-AG in TG, TNC and PAG were decreased in TBI animals, significantly elevated and further reduced by the selective inhibitors of 2-AG hydrolytic and synthetic enzymes, respectively. CONCLUSION: Enhancing endogenous levels of 2-AG appears to be an effective strategy for the treatment of PTH by attenuating pain initiation and transmission in the trigeminal pathway and facilitating descending pain inhibitory modulation.