The Non-enzymatic Reactivity of the Acyl-linked Metabolites of Mefenamic Acid Towards Amino and Thiol Functional Group Biomolecules
- Drug metabolism and disposition: the biological fate of chemicals
- Published almost 5 years ago
Mefenamic acid, (MFA), a carboxylic acid-containing nonsteroidal anti-inflammatory drug (NSAID) is metabolized into the chemically-reactive, MFA-1-O-acyl-glucuronide (MFA-1-O-G), MFA-acyl-adenylate (MFA-AMP), and the MFA-S-acyl-CoA (MFA-CoA), all of which are electrophilic and capable of acylating nucleophilic sites on biomolecules. In this study, we investigate the non-enzymatic ability of each MFA acyl-linked metabolite to transacylate amino and thiol functional groups on the acceptor biomolecules glycine (Gly), taurine (Tau), glutathione (GSH), and N-acetylcysteine (NAC). In vitro incubations with each of the MFA acyl-linked metabolites (1 μM) in buffer under physiological conditions with Gly, Tau, GSH, or NAC (10 mM) revealed that MFA-CoA was 11.5- and 19.5-fold more reactive than MFA-AMP towards the acylation of cysteine-sulfhydryl groups of GSH and NAC, respectively. However, MFA-AMP was more reactive towards both Gly and Tau, 17.5-fold more reactive towards the N-acyl-amidation of taurine than its corresponding CoA thioester, while MFA-CoA displayed little reactivity towards glycine. Additionally, MFA-GSH was 5.6- and 108-fold more reactive towards NAC than MFA-CoA and MFA-AMP, respectively. In comparison to MFA-AMP and MFA-CoA, MFA-1-O-G was not significantly reactive towards all four bionucleophiles. MFA-AMP, MFA-CoA, MFA-1-O-G, MFA-GSH, and MFA-Tau were also detected in rat in vitro hepatocyte MFA (100 μM) incubations while MFA-Gly was not. These results demonstrate that MFA-AMP selectively reacts nonenzymatically with the amino functional groups of glycine and lysine, MFA-CoA selectively reacts nonenzymatically with the thiol functional groups of GSH and NAC, and MFA-GSH reacts nonenzymatically with the thiol functional group of GSH, all of which may potentially elicit an idiosyncratic toxicity in vivo.
Background Studies have suggested an association between frequent acetaminophen use and asthma-related complications among children, leading some physicians to recommend that acetaminophen be avoided in children with asthma; however, appropriately designed trials evaluating this association in children are lacking. Methods In a multicenter, prospective, randomized, double-blind, parallel-group trial, we enrolled 300 children (age range, 12 to 59 months) with mild persistent asthma and assigned them to receive either acetaminophen or ibuprofen when needed for the alleviation of fever or pain over the course of 48 weeks. The primary outcome was the number of asthma exacerbations that led to treatment with systemic glucocorticoids. Children in both groups received standardized asthma-controller therapies that were used in a simultaneous, factorially linked trial. Results Participants received a median of 5.5 doses (interquartile range, 1.0 to 15.0) of trial medication; there was no significant between-group difference in the median number of doses received (P=0.47). The number of asthma exacerbations did not differ significantly between the two groups, with a mean of 0.81 per participant with acetaminophen and 0.87 per participant with ibuprofen over 46 weeks of follow-up (relative rate of asthma exacerbations in the acetaminophen group vs. the ibuprofen group, 0.94; 95% confidence interval, 0.69 to 1.28; P=0.67). In the acetaminophen group, 49% of participants had at least one asthma exacerbation and 21% had at least two, as compared with 47% and 24%, respectively, in the ibuprofen group. Similarly, no significant differences were detected between acetaminophen and ibuprofen with respect to the percentage of asthma-control days (85.8% and 86.8%, respectively; P=0.50), use of an albuterol rescue inhaler (2.8 and 3.0 inhalations per week, respectively; P=0.69), unscheduled health care utilization for asthma (0.75 and 0.76 episodes per participant, respectively; P=0.94), or adverse events. Conclusions Among young children with mild persistent asthma, as-needed use of acetaminophen was not shown to be associated with a higher incidence of asthma exacerbations or worse asthma control than was as-needed use of ibuprofen. (Funded by the National Institutes of Health; AVICA ClinicalTrials.gov number, NCT01606319 .).
To prevent pain inhibiting their performance, many athletes ingest over-the-counter (OTC) analgesics before competing. We aimed at defining the use of analgesics and the relation between OTC analgesic use/dose and adverse events (AEs) during and after the race, a relation that has not been investigated to date.
Among pregnant women ibuprofen is one of the most frequently used pharmaceutical compounds with up to 28% reporting use. Regardless of this, it remains unknown whether ibuprofen could act as an endocrine disruptor as reported for fellow analgesics paracetamol and aspirin. To investigate this, we exposed human fetal testes (7-17 gestational weeks (GW)) to ibuprofen using ex vivo culture and xenograft systems. Ibuprofen suppressed testosterone and Leydig cell hormone INSL3 during culture of 8-9 GW fetal testes with concomitant reduction in expression of the steroidogenic enzymes CYP11A1, CYP17A1 and HSD17B3, and of INSL3. Testosterone was not suppressed in testes from fetuses younger than 8 GW, older than 10-12 GW, or in second trimester xenografted testes (14-17 GW). Ex vivo, ibuprofen also affected Sertoli cell by suppressing AMH production and mRNA expression of AMH, SOX9, DHH, and COL2A1. While PGE2 production was suppressed by ibuprofen, PGD2 production was not. Germ cell transcripts POU5F1, TFAP2C, LIN28A, ALPP and KIT were also reduced by ibuprofen. We conclude that, at concentrations relevant to human exposure and within a particular narrow ‘early window’ of sensitivity within first trimester, ibuprofen causes direct endocrine disturbances in the human fetal testis and alteration of the germ cell biology.
Fragranced consumer products-such as air fresheners, cleaning supplies, and personal care products- pervade society. This study investigated the occurrence and types of adverse effects associated with exposure to fragranced products in Australia, and opportunities for prevention. Data were collected in June 2016 using an on-line survey with a representative national sample (n = 1098). Overall, 33% of Australians report health problems, such as migraine headaches and asthma attacks, when exposed to fragranced products. Of these health effects, more than half (17.1%) could be considered disabling under the Australian Disability Discrimination Act. Additionally, 7.7% of Australians have lost workdays or a job due to illness from fragranced product exposure in the workplace, 16.4% reported health problems when exposed to air fresheners or deodorizers, 15.3% from being in a room after it was cleaned with scented products, and 16.7% would enter but then leave a business as quickly as possible due to fragranced products. About twice as many respondents would prefer that workplaces, health care facilities and professionals, hotels, and airplanes were fragrance-free rather than fragranced. While 73.7% were not aware that fragranced products, even ones called green and organic, emitted hazardous air pollutants, 56.3% would not continue to use a product if they knew it did. This is the first study in Australia to assess the extent of adverse effects associated with exposure to common fragranced products. It provides compelling evidence for the importance and value of reducing fragranced product exposure in order to reduce and prevent adverse health effects and costs.
Paracetamol overdose is common but patient stratification is suboptimal. We investigated the usefulness of new biomarkers that have either enhanced liver specificity (microRNA-122 [miR-122]) or provide mechanistic insights (keratin-18 [K18], high mobility group box-1 [HMGB1], and glutamate dehydrogenase [GLDH]). The use of these biomarkers could help stratify patients for their risk of liver injury at hospital presentation.
Background Colchicine is effective for the treatment of recurrent pericarditis. However, conclusive data are lacking regarding the use of colchicine during a first attack of acute pericarditis and in the prevention of recurrent symptoms. Methods In a multicenter, double-blind trial, eligible adults with acute pericarditis were randomly assigned to receive either colchicine (at a dose of 0.5 mg twice daily for 3 months for patients weighing >70 kg or 0.5 mg once daily for patients weighing ≤70 kg) or placebo in addition to conventional antiinflammatory therapy with aspirin or ibuprofen. The primary study outcome was incessant or recurrent pericarditis. Results A total of 240 patients were enrolled, and 120 were randomly assigned to each of the two study groups. The primary outcome occurred in 20 patients (16.7%) in the colchicine group and 45 patients (37.5%) in the placebo group (relative risk reduction in the colchicine group, 0.56; 95% confidence interval, 0.30 to 0.72; number needed to treat, 4; P<0.001). Colchicine reduced the rate of symptom persistence at 72 hours (19.2% vs. 40.0%, P=0.001), the number of recurrences per patient (0.21 vs. 0.52, P=0.001), and the hospitalization rate (5.0% vs. 14.2%, P=0.02). Colchicine also improved the remission rate at 1 week (85.0% vs. 58.3%, P<0.001). Overall adverse effects and rates of study-drug discontinuation were similar in the two study groups. No serious adverse events were observed. Conclusions In patients with acute pericarditis, colchicine, when added to conventional antiinflammatory therapy, significantly reduced the rate of incessant or recurrent pericarditis. (Funded by former Azienda Sanitaria Locale 3 of Turin [now Azienda Sanitaria Locale 2] and Acarpia; ICAP ClinicalTrials.gov number, NCT00128453 .).
Codeine has been prescribed to pediatric patients for many decades as both an analgesic and an antitussive agent. Codeine is a prodrug with little inherent pharmacologic activity and must be metabolized in the liver into morphine, which is responsible for codeine’s analgesic effects. However, there is substantial genetic variability in the activity of the responsible hepatic enzyme, CYP2D6, and, as a consequence, individual patient response to codeine varies from no effect to high sensitivity. Drug surveillance has documented the occurrence of unanticipated respiratory depression and death after receiving codeine in children, many of whom have been shown to be ultrarapid metabolizers. Patients with documented or suspected obstructive sleep apnea appear to be at particular risk because of opioid sensitivity, compounding the danger among rapid metabolizers in this group. Recently, various organizations and regulatory bodies, including the World Health Organization, the US Food and Drug Administration, and the European Medicines Agency, have promulgated stern warnings regarding the occurrence of adverse effects of codeine in children. These and other groups have or are considering a declaration of a contraindication for the use of codeine for children as either an analgesic or an antitussive. Additional clinical research must extend the understanding of the risks and benefits of both opioid and nonopioid alternatives for orally administered, effective agents for acute and chronic pain.
Primary dysmenorrhea is common among women of reproductive age. Non-steroidal anti-inflammatory drugs and oral contraceptives are effective treatments, although the failure rate is around 20-25%. Therefore additional evidence-based treatments are needed. In recent years, the use of smartphone applications (apps) has increased rapidly and may support individuals in self-management strategies.
Prostaglandin E2 is essential for efficacious skeletal muscle stem-cell function, augmenting regeneration and strength
- Proceedings of the National Academy of Sciences of the United States of America
- Published about 1 year ago
Skeletal muscles harbor quiescent muscle-specific stem cells (MuSCs) capable of tissue regeneration throughout life. Muscle injury precipitates a complex inflammatory response in which a multiplicity of cell types, cytokines, and growth factors participate. Here we show that Prostaglandin E2 (PGE2) is an inflammatory cytokine that directly targets MuSCs via the EP4 receptor, leading to MuSC expansion. An acute treatment with PGE2 suffices to robustly augment muscle regeneration by either endogenous or transplanted MuSCs. Loss of PGE2 signaling by specific genetic ablation of the EP4 receptor in MuSCs impairs regeneration, leading to decreased muscle force. Inhibition of PGE2 production through nonsteroidal anti-inflammatory drug (NSAID) administration just after injury similarly hinders regeneration and compromises muscle strength. Mechanistically, the PGE2 EP4 interaction causes MuSC expansion by triggering a cAMP/phosphoCREB pathway that activates the proliferation-inducing transcription factor, Nurr1 Our findings reveal that loss of PGE2 signaling to MuSCs during recovery from injury impedes muscle repair and strength. Through such gain- or loss-of-function experiments, we found that PGE2 signaling acts as a rheostat for muscle stem-cell function. Decreased PGE2 signaling due to NSAIDs or increased PGE2 due to exogenous delivery dictates MuSC function, which determines the outcome of regeneration. The markedly enhanced and accelerated repair of damaged muscles following intramuscular delivery of PGE2 suggests a previously unrecognized indication for this therapeutic agent.