SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Paracetamol

486

289

 To investigate the cardiovascular safety of non-steroidal anti-inflammatory drugs (NSAIDs) and estimate the risk of hospital admission for heart failure with use of individual NSAIDs.

Concepts: Hypertension, Glucocorticoid, Non-steroidal anti-inflammatory drug, Anti-inflammatory, Paracetamol, ACE inhibitor

268

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used and have been associated with increased cardiovascular risk. Nonetheless, it remains unknown whether use of NSAIDs is associated with out-of-hospital cardiac arrest (OHCA).

Concepts: Non-steroidal anti-inflammatory drug, Anti-inflammatory, Paracetamol

247

The common non-steroidal anti-inflammatory drug ibuprofen has been associated with a reduced risk of some age-related pathologies. However, a general pro-longevity role for ibuprofen and its mechanistic basis remains unclear. Here we show that ibuprofen increased the lifespan of Saccharomyces cerevisiae, Caenorhabditis elegans and Drosophila melanogaster, indicative of conserved eukaryotic longevity effects. Studies in yeast indicate that ibuprofen destabilizes the Tat2p permease and inhibits tryptophan uptake. Loss of Tat2p increased replicative lifespan (RLS), but ibuprofen did not increase RLS when Tat2p was stabilized or in an already long-lived strain background impaired for aromatic amino acid uptake. Concomitant with lifespan extension, ibuprofen moderately reduced cell size at birth, leading to a delay in the G1 phase of the cell cycle. Similar changes in cell cycle progression were evident in a large dataset of replicatively long-lived yeast deletion strains. These results point to fundamental cell cycle signatures linked with longevity, implicate aromatic amino acid import in aging and identify a largely safe drug that extends lifespan across different kingdoms of life.

Concepts: Genome, Chromosome, Fungus, Model organism, Cell cycle, Saccharomyces cerevisiae, Non-steroidal anti-inflammatory drug, Paracetamol

205

Dysfunction of cell-cell tight junction (TJ) adhesions is a major feature in the pathogenesis of various diseases. Liver TJs preserve cellular polarity by delimiting functional bile-canalicular structures, forming the blood-biliary barrier. In acetaminophen-hepatotoxicity, the mechanism by which tissue cohesion and polarity are affected remains unclear. Here, we demonstrate that acetaminophen, even at low-dose, disrupts the integrity of TJ and cell-matrix adhesions, with indicators of cellular stress with liver injury in the human hepatic HepaRG cell line, and primary hepatocytes. In mouse liver, at human-equivalence (therapeutic) doses, dose-dependent loss of intercellular hepatic TJ-associated ZO-1 protein expression was evident with progressive clinical signs of liver injury. Temporal, dose-dependent and specific disruption of the TJ-associated ZO-1 and cytoskeletal-F-actin proteins, correlated with modulation of hepatic ultrastructure. Real-time impedance biosensing verified in vitro early, dose-dependent quantitative decreases in TJ and cell-substrate adhesions. Whereas treatment with NAPQI, the reactive metabolite of acetaminophen, or the PKCα-activator and TJ-disruptor phorbol-12-myristate-13-acetate, similarly reduced TJ integrity, which may implicate oxidative stress and the PKC pathway in TJ destabilization. These findings are relevant to the clinical presentation of acetaminophen-hepatotoxicity and may inform future mechanistic studies to identify specific molecular targets and pathways that may be altered in acetaminophen-induced hepatic depolarization.

Concepts: Liver, Paracetamol, Hepatocyte, Tight junction protein 1

183

There is compelling evidence to support an aetiological role for inflammation, oxidative and nitrosative stress (O&NS), and mitochondrial dysfunction in the pathophysiology of major neuropsychiatric disorders, including depression, schizophrenia, bipolar disorder, and Alzheimer’s disease (AD). These may represent new pathways for therapy. Aspirin is a non-steroidal anti-inflammatory drug that is an irreversible inhibitor of both cyclooxygenase (COX)-1 and COX-2, It stimulates endogenous production of anti-inflammatory regulatory ‘braking signals’, including lipoxins, which dampen the inflammatory response and reduce levels of inflammatory biomarkers, including C-reactive protein, tumor necrosis factor- and interleukin (IL)–6 , but not negative immunoregulatory cytokines, such as IL-4 and IL-10. Aspirin can reduce oxidative stress and protect against oxidative damage. Early evidence suggests there are beneficial effects of aspirin in preclinical and clinical studies in mood disorders and schizophrenia, and epidemiological data suggests that high-dose aspirin is associated with a reduced risk of AD. Aspirin, one of the oldest agents in medicine, is a potential new therapy for a range of neuropsychiatric disorders, and may provide proof-of-principle support for the role of inflammation and O&NS in the pathophysiology of this diverse group of disorders.

Concepts: Inflammation, Cyclooxygenase, Anti-inflammatory, Paracetamol, Mental disorder, Schizophrenia, Bipolar disorder, Tumor necrosis factor-alpha

166

We have previously described the development of genetic models to study the in vivo functions of the hepatic cytochrome P450 system, through the hepatic deletion of either cytochrome P450 oxidoreductase (POR; HRN line) or cytochrome b5 (Cyb5; HBN line). However, HRN mice still exhibit low levels of mono-oxygenase activity, in spite of the absence of detectable reductase protein. To investigate whether this is because cytochrome b5 and cytochrome b5 reductase can act as sole electron donors to the P450 system, we have crossed HRN with HBN mice to generate a line lacking hepatic expression of both electron donors (HBRN). HBRN mice exhibited exacerbation of the phenotypic characteristics of the HRN line - liver enlargement, hepatosteatosis and increased expression of certain cytochrome P450s. Also, drug metabolising activities in vitro were further reduced relative to the HRN model, in some cases to undetectable levels. Pharmacokinetic studies in vivo demonstrated that midazolam half-life, Cmax and area under the concentration-time curve (AUC) were increased, and clearance was decreased, to a greater extent in the HBRN line than in either the HBN or HRN model. Microsomal incubations using NADPH concentrations below the apparent Km of cytochrome b5 reductase, but well above that for POR, led to the virtual elimination of 7-benzyloxyquinoline turnover in HRN samples. These data provide strong evidence that cytochrome b5/cytochrome b5 reductase can act as a sole electron donors to the cytochrome P450 system in vitro and in vivo.

Concepts: Cytochrome P450, Paracetamol, CYP3A4, P450-containing systems, Cytochrome P450 reductase

166

Cycloxygenase-2 (COX-2) is an attractive target for molecular imaging because it is an inducible enzyme that is expressed in response to inflammatory and proliferative stimuli. Recently, we reported that conjugation of indomethacin with carboxy-X-rhodamine dyes results in the formation of effective, targeted, optical imaging agents able to detect COX-2 in inflammatory tissues and pre-malignant and malignant tumors (Uddin et al. Cancer Res. 2010, 70, 3618-3627). The present paper summarizes the details of the structure-activity relationship (SAR) studies performed for lead optimization of these dyes. A wide range of fluorescent conjugates were designed and synthesized, and each of them was tested for their ability to selectively inhibit COX-2 as the purified protein and in human cancer cells. The SAR study revealed that indomethacin conjugates are the best COX-2-targeted agents compared to the other carboxylic acid-containing non-steroidal anti-inflammatory drugs (NSAIDs) or COX-2-selective inhibitors (COXIBs). An n-butyldiamide linker is optimal for tethering bulky fluorescent functionalities onto the NSAID or COXIB cores. The activity of conjugates also depends on the size, shape, and electronic properties of the organic fluorophores. These reagents are taken up by COX-2-expressing cells in culture, and the uptake is blocked by pretreatment with a COX inhibitor. In in vivo settings, these reagents become highly enriched in COX-2-expressing tumors compared to surrounding normal tissue, and they accumulate selectively in COX-2-expressing tumors as compared with COX-2-negative tumors implanted in the same mice. Thus, COX-2-targeted fluorescent inhibitors are useful for preclinical and clinical detection of lesions containing elevated levels of COX-2.

Concepts: Cancer, Cyclooxygenase, Non-steroidal anti-inflammatory drug, Anti-inflammatory, Paracetamol, Ibuprofen, Diclofenac, Celecoxib

165

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.

Concepts: Amino acid, Amine, Functional group, Disulfide bond, Non-steroidal anti-inflammatory drug, Paracetamol, Ibuprofen, Carboxylic acid

99

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 .).

Concepts: Asthma, Median, Interquartile range, Paracetamol, Aspirin, Normal distribution, Inhaler, Nebulizer