NSAIDs: eNdocannabinoid stimulating anti-inflammatory drugs?

Interaction of endocannabinoid system and cyclooxygenase metabolites with fatty acid amide hydrolase and cyclooxygenase enzyme activities on contractile responses in rat vas deferens tissue

The endocannabinoid system and prostaglandins are important modulators in the genitourinary system. This study aimed to investigate the possible interactions between the endocannabinoid system and the cyclooxygenase (COX) pathway on rat vas deferens. For this purpose, the concentration responses of the endocannabinoid anandamide, prostaglandin F2α analog latanoprost, and prostaglandin E1 analog misoprostol on the electrical field stimulation (EFS)-induced contractile responses were obtained. The concentration responses to anandamide were obtained again in the presence of nonselective COX inhibitor flurbiprofen and prostaglandin analogs, while the concentration responses of latanoprost and misoprostol were obtained in the presence of cannabinoid receptor antagonists and fatty acid amide hydrolase (FAAH) enzyme inhibitor URB597. FAAH, COX-1, and COX-2 enzyme levels in vas deferens tissue samples were also determined. The cumulative addition of anandamide was not different from the vehicle; however, the EFS-induced contractile responses were significantly increased with the incubation of latanoprost or flurbiprofen in the prostatic portion. Flurbiprofen and misoprostol decreased FAAH enzyme levels in both portions of the vas deferens, while latanoprost induced the inhibition in the prostatic portion. The cumulative administration of latanoprost and misoprostol significantly enhanced the contractile responses in the prostatic portion. This effect of latanoprost was significantly antagonized by URB597 and AM251. The enhancing effect of misoprostol was antagonized by anandamide, URB597, AM251, and AM630. Anandamide, AM251, AM630, and URB597 decreased enzyme levels of COX-1 and COX-2 in both portions of the vas deferens. These results demonstrate an intricate crosstalk between endocannabinoids and prostaglandins in modulation of the vas deferens contractility.

Traditional Uses, Phytochemistry, and Pharmacological Activities of Coleus amboinicus: A Comprehensive Review

Coleus amboinicus Benth., also known as Plectranthus amboinicus (Lour.) Spreng., is a perennial plant from the Lamiaceae family commonly found in tropical and warm regions of Africa, Asia, and Australia. Folk medicine commonly employs this remedy to address various ailments, including but not limited to asthma, headaches, skin disorders, coughs, constipation, colds, and fevers. Several phytoconstituents from various phytochemical classes, such as phenolics, terpenoids, phenolic acids, flavonoids, flavones, and tannins, have been identified in Coleus amboinicus up to the present time. Numerous pharmacological properties of Coleus amboinicus crude extracts have been documented through both in vitro and in vivo studies, including but not limited to antitumor, antibacterial, antifungal, antiprotozoal, anti-inflammatory, antioxidant, antidiabetic, wound healing, analgesic, antirheumatic, and various other therapeutic effects. Due to its extensive history of traditional usage, the diverse array of bioactive phytochemicals, and numerous established pharmacological activities, Coleus amboinicus is widely regarded as having significant potential for clinical applications and warrants further exploration, development, and exploitation through research. With this context, the present study gathers information on the occurrence, biological description, cultivation, and nutritional values of Coleus amboinicus. Furthermore, it thoroughly discusses various phytoconstituents, along with their classes, present in Coleus amboinicus, followed by detailed descriptions of their pharmacological activities based on recent literature.

Changing paradigms in the treatment of tuberculosis

Tuberculosis, caused by Mycobacterium tuberculosis, is a disease long dealt with, but still remains the second leading cause of death world-wide. The current anti-tubercular chemotherapy primarily targets the microbial pathogenesis, which however, is failing due to the development of drug resistance. Moreover, with fewer new drugs reaching the market, there is a need to focus on alternate treatment approaches that could be used as stand-alone or adjunct therapy and the existing drugs, referred to as Track II chemotherapy. This article is an attempt to review the changing global patterns of tuberculosis and its treatment. Further, newer drug delivery approaches like multi-particulate drug carriers which increase the therapeutic efficacy and bring down the systemic toxicity associated with drugs have also been discussed. There is also a need to use interventions which can be used as Track II therapy. Host-directed therapeutics (HDT) is an emerging area concept in which host cell functions and hence the response to pathogens can be modulated, which can help manage TB. HDT decreases damage induced due to inflammation and necrosis in the lungs and other parts of the body due to the disease. Various immuno-modulatory pathways have been discussed in this review which could be explored further to treat TB. An in-depth understanding of multi-particulate drug carriers and HDT could help in dealing with tuberculosis; however, there is still a long way to go.

Acetaminophen, Nonsteroidal Anti-Inflammatory Drugs, and Hypertension

Acetaminophen is widely regarded as a safe therapy for pain and fever in patients with cardiovascular disease and those taking anticoagulants. However, recent studies report that acetaminophen, like most other nonsteroidal anti-inflammatory drugs, increases blood pressure, and a formulation containing sodium increases cardiovascular risk. Those findings call into question guidelines recommending acetaminophen for patients with cardiovascular disease and pain, and those taking anticoagulants. We review evidence that acetaminophen has effects in common with nonsteroidal anti-inflammatory drugs, and its influence on coagulation via effects on vitamin K metabolism. Possible alternatives to acetaminophen for patients with pain are discussed.

Effects of non-steroidal anti-inflammatory drugs and other eicosanoid pathway modifiers on antiviral and allergic responses: EAACI task force on eicosanoids consensus report in times of COVID-19

Non‐steroidal anti‐inflammatory drugs (NSAIDs) and other eicosanoid pathway modifiers are among the most ubiquitously used medications in the general population. Their broad anti‐inflammatory, antipyretic, and analgesic effects are applied against symptoms of respiratory infections, including SARS‐CoV‐2, as well as in other acute and chronic inflammatory diseases that often coexist with allergy and asthma. However, the current pandemic of COVID‐19 also revealed the gaps in our understanding of their mechanism of action, selectivity, and interactions not only during viral infections and inflammation, but also in asthma exacerbations, uncontrolled allergic inflammation, and NSAIDs‐exacerbated respiratory disease (NERD). In this context, the consensus report summarizes currently available knowledge, novel discoveries, and controversies regarding the use of NSAIDs in COVID‐19, and the role of NSAIDs in asthma and viral asthma exacerbations. We also describe here novel mechanisms of action of leukotriene receptor antagonists (LTRAs), outline how to predict responses to LTRA therapy and discuss a potential role of LTRA therapy in COVID‐19 treatment. Moreover, we discuss interactions of novel T2 biologicals and other eicosanoid pathway modifiers on the horizon, such as prostaglandin D2 antagonists and cannabinoids, with eicosanoid pathways, in context of viral infections and exacerbations of asthma and allergic diseases. Finally, we identify and summarize the major knowledge gaps and unmet needs in current eicosanoid research.

Comprehensive review on mechanism of action, resistance and evolution of antimycobacterial drugs

Tuberculosis is one of the deadliest infectious diseases existing in the world since ancient times and still possesses serious threat across the globe. Each year the number of cases increases due to high drug resistance shown by Mycobacterium tuberculosis (Mtb). Available antimycobacterial drugs have been classified as First line, Second line and Third line antibiotics depending on the time of their discoveries and their effectiveness in the treatment. These antibiotics have a broad range of targets ranging from cell wall to metabolic processes and their non-judicious and uncontrolled usage in the treatment for years has created a significant problem called multi-drug resistant (MDR) tuberculosis. In this review, we have summarized the mechanism of action of all the classified antibiotics currently in use along with the resistance mechanisms acquired by Mtb. We have focused on the new drug candidates/repurposed drugs, and drug in combinations, which are in clinical trials for either treating the MDR tuberculosis more effectively or involved in reducing the time required for the chemotherapy of drug sensitive TB. This information is not discussed very adequately on a single platform. Additionally, we have discussed the recent technologies that are being used to discover novel resistance mechanisms acquired by Mtb and for exploring novel drugs. The story of intrinsic resistance mechanisms and evolution in Mtb is far from complete. Therefore, we have also discussed intrinsic resistance mechanisms of Mtb and their evolution with time, emphasizing the hope for the development of novel antimycobacterial drugs for effective therapy of tuberculosis.

Endocannabinoid system alterations in Alzheimer's disease: A systematic review of human studies

Studies investigating alterations of the endocannabinoid system (ECS) in Alzheimer's disease (AD) in humans have reported inconsistent findings so far. We performed a systematic review of studies examining alterations of the ECS specifically within humans with AD or mild cognitive impairment (MCI), including neuroimaging studies, studies of serum and cerebrospinal fluid biomarkers, and post-mortem studies. We attempted to identify reported changes in the expression and activity of: cannabinoid receptors 1 and 2; anandamide (AEA); 2-arachidonoylglycerol (2-AG); monoacylglycerol lipase (MAGL); fatty acid amide hydrolase (FAAH); and transient receptor potential cation channel V1 (TRPV1). Twenty-two studies were identified for inclusion. Mixed findings were reported for most aspects of the ECS in AD, making it difficult to identify a particular profile of ECS alterations characterising AD. The included studies tended to be small, methodologically heterogeneous, and frequently did not control for important potential confounders, such as pathological progression of AD. Eight studies correlated ECS alterations with neuropsychometric performance measures, though studies infrequently examined behavioural and neuropsychiatric correlates. PROSPERO database identifier: CRD42018096249.

Non-opioid Analgesics and the Endocannabinoid System

Non-steroidal anti-inflammatory drugs produce antinociceptive effects mainly through peripheral cyclooxygenase inhibition. In opposition to the classical non-steroidal anti-inflammatory drugs, paracetamol and dipyrone exert weak anti-inflammatory activity, their antinociceptive effects appearing to be mostly due to mechanisms other than peripheral cyclooxygenase inhibition. In this review, we classify classical non-steroidal anti-inflammatory drugs, paracetamol and dipyrone as “non-opioid analgesics” and discuss the mechanisms mediating participation of the endocannabinoid system in their antinociceptive effects. Non-opioid analgesics and their metabolites may activate cannabinoid receptors, as well as elevate endocannabinoid levels through different mechanisms: reduction of endocannabinoid degradation via fatty acid amide hydrolase and/or cyclooxygenase-2 inhibition, mobilization of arachidonic acid for the biosynthesis of endocannabinoids due to cyclooxygenase inhibition, inhibition of endocannabinoid cellular uptake directly or through the inhibition of nitric oxide synthase production, and induction of endocannabinoid release.

Inhibition of Fast Nerve Conduction Produced by Analgesics and Analgesic Adjuvants-Possible Involvement in Pain Alleviation

Nociceptive information is transmitted from the periphery to the cerebral cortex mainly by action potential (AP) conduction in nerve fibers and chemical transmission at synapses. Although this nociceptive transmission is largely inhibited at synapses by analgesics and their adjuvants, it is possible that the antinociceptive drugs inhibit nerve AP conduction, contributing to their antinociceptive effects. Many of the drugs are reported to inhibit the nerve conduction of AP and voltage-gated Na⁺ and K⁺ channels involved in its production. Compound action potential (CAP) is a useful measure to know whether drugs act on nerve AP conduction. Clinically-used analgesics and analgesic adjuvants (opioids, non-steroidal anti-inflammatory drugs, ₂-adrenoceptor agonists, antiepileptics, antidepressants and local anesthetics) were found to inhibit fast-conducting CAPs recorded from the frog sciatic nerve by using the air-gap method. Similar actions were produced by antinociceptive plant-derived chemicals. Their inhibitory actions depended on the concentrations and chemical structures of the drugs. This review article will mention the inhibitory actions of the antinociceptive compounds on CAPs in frog and mammalian peripheral (particularly, sciatic) nerves and on voltage-gated Na⁺ and K⁺ channels involved in AP production. Nerve AP conduction inhibition produced by analgesics and analgesic adjuvants is suggested to contribute to at least a part of their antinociceptive effects.

Endocannabinoid and N-acylethanolamide levels in rat brain and spinal cord following systemic dipyrone and paracetamol administration

The cannabinoid system has been suspected to play a role in the mechanisms of action of dipyrone and paracetamol. Our purpose was to measure the local endocannabinoid and N-acylethanolamide levels in the brain and spinal cord of rats following dipyrone and paracetamol administration. Nociception was assessed 1, 5, and 12 h following drug injections in Wistar rats, using tail-flick and hot-plate tests. The antinociceptive effects of dipyrone (150, 300, and 600 mg/kg, i.p.) and paracetamol (30, 100, and 300 mg/kg, i.p.) were observed. After administration of the highest doses of dipyrone and paracetamol, endocannabinoid (N-arachidonoylethanolamide (AEA), 2-arachidonoylglycerol (2-AG)) and N-acylethanolamide (palmitoylethanolamide (PEA), oleoylethanolamide (OEA)) levels were measured in the periaqueductal gray (PAG), rostral ventromedial medulla (RVM), and spinal cords of rats using tandem mass spectrometry with liquid chromatography. Increased 2-AG levels were observed in the PAG and the RVM 12 h after paracetamol injection; dipyrone exerted no action on 2-AG levels. Analgesic administrations led to a reduction in AEA levels in the RVM and spinal cord; similar decreases in PEA and OEA levels were observed in the RVM and the spinal cord. Dipyrone and paracetamol administrations appear to exert complicated effects on endocannabinoid and N-acylethanolamide levels in rats.

Inhibition by non-steroidal anti-inflammatory drugs of compound action potentials in frog sciatic nerve fibers

AIMS

Although antinociception produced by non-steroidal anti-inflammatory drugs (NSAIDs) is partly attributed to nerve conduction inhibition, this has not been thoroughly examined yet. The aim of the present study was to reveal quantitatively how various types of NSAIDs affect compound action potentials (CAPs), a measure of nerve conduction.

MAIN METHODS

CAPs were recorded from the frog sciatic nerve by using the air-gap method.

KEY FINDINGS

Soaking the sciatic nerve with acetic acid-based NSAIDs (diclofenac and aceclofenac) reduced the peak amplitude of CAP in a concentration-dependent manner; their IC₅₀ values were 0.94 and 0.47 mM, respectively. Other acetic acid-based NSAIDs (indomethacin, acemetacin and etodolac) also inhibited CAPs [the extent of inhibition: some 40% (1 mM), 40% (0.5 mM) and 15% (1 mM), respectively], except for sulindac and felbinac at 1 mM that had no effects on CAP peak amplitudes. A similar inhibition was produced by fenamic acid-based NSAIDs [tolfenamic acid (IC₅₀ = 0.29 mM), meclofenamic acid (0.19 mM), flufenamic acid (0.22 mM) and mefenamic acid] which are similar in chemical structure to diclofenac and aceclofenac; their derivatives (2,6-dichlorodiphenylamine and N-phenylanthranilic acid) also inhibited. On the other hand, salicylic acid-based (aspirin), propionic acid-based (ketoprofen, naproxen, ibuprofen, loxoprofen and flurbiprofen) and enolic acid-based (meloxicam and piroxicam) NSAIDs had no effects on CAP peak amplitudes.

SIGNIFICANCE

At least a part of antinociception produced by NSAIDs used as a dermatological drug to alleviate pain may be attributed to their inhibitory effects on nerve conduction, which depend on the chemical structures of NSAIDs.

Maintenance of the Innate Seizure Threshold by Cyclooxygenase-2 is Not Influenced by the Translational Silencer, T-cell Intracellular Antigen-1

Activity of neuronal cyclooxygenase-2 (COX-2), a primary source of PG synthesis in the normal brain, is enhanced by excitatory neurotransmission and this is thought to be involved in seizure suppression. Results herein showing that the incidence of pentylenetetrazole (PTZ)-induced convulsions is suppressed in transgenic mice overexpressing COX-2 in neurons support this notion. T-cell intracellular antigen-1 (TIA-1) is an mRNA binding protein that is known to bind to COX-2 mRNA and repress its translation in non-neuronal cell types. An examination of the expression profile of TIA-1 protein in the normal brain indicated that it is expressed broadly by neurons, including those that express COX-2. However, whether TIA-1 regulates COX-2 protein levels in neurons is not known. The purpose of this study was to test the possibility that deletion of TIA-1 increases basal COX-2 expression in neurons and consequently raises the seizure threshold. Results demonstrate that neither the basal nor seizure-induced expression profiles of COX-2 were altered in mice lacking a functional TIA-1 gene suggesting that TIA-1 does not contribute to regulation of COX-2 protein expression in neurons. The acute PTZ-induced seizure threshold was also unchanged in mice lacking TIA-1 protein, indicating that this RNA binding protein does not influence the innate seizure threshold. Nevertheless, the results raise the possibility that the level of neuronal COX-2 expression may be a determinant of the innate seizure threshold and suggest that a better understanding of the regulation of COX-2 expression in the brain could provide new insight into the molecular mechanisms that suppress seizure induction.

Host-Directed Therapeutic Strategies for Tuberculosis

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a leading cause of morbidity and mortality in humans worldwide. Currently, the standard treatment for TB involves multiple antibiotics administered for at least 6 months. Although multiple antibiotics therapy is necessary to prevent the development of drug resistance, the prolonged duration of treatment, combined with toxicity of drugs, contributes to patient non-compliance that can leads to the development of drug-resistant Mtb (MDR and XDR) strains. The existence of comorbid conditions, including HIV infection, not only complicates TB treatment but also elevates the mortality rate of patients. These facts underscore the need for the development of new and/or improved TB treatment strategies. Host-directed therapy (HDT) is a new and emerging concept in the treatment of TB, where host response is modulated by treatment with small molecules, with or without adjunct antibiotics, to achieve better control of TB. Unlike antibiotics, HDT drugs act by directly modulating host cell functions; therefore, development of drug resistance by infecting Mtb is avoided. Thus, HDT is a promising treatment strategy for the management of MDR- and XDR-TB cases as well as for patients with existing chronic, comorbid conditions such as HIV infection or diabetes. Functionally, HDT drugs fine-tune the antimicrobial activities of host immune cells and limit inflammation and tissue damage associated with TB. However, current knowledge and clinical evidence is insufficient to implement HDT molecules as a stand-alone, without adjunct antibiotics, therapeutic modality to treat any form of TB in humans. In this review, we discuss the recent findings on small molecule HDT agents that target autophagy, vitamin D pathway, and anti-inflammatory response as adjunctive agents along with standard antibiotics for TB therapy. Data from recent publications show that this approach has the potential to improve clinical outcome and can help to reduce treatment duration. Thus, HDT can contribute to global TB control programs by potentially increasing the efficiency of anti-TB treatment.

Adolescent social rejection alters pain processing in a CB1 receptor dependent manner

Experiences of social rejection represent a major source of distress and in particular peer rejection during adolescence has been implicated in various psychiatric disorders. Moreover, experimentally induced acute social rejection alters pain perception in humans, implicating overlapping neurocircuits for social and physical pains. We recently demonstrated that rearing of adolescent Wistar rats with inadequate, less playful play partners (Fischer 344) persistently decreases pain sensitivity, although the detailed mechanisms mediating the aversiveness during the social encounter remained unsettled. With the present study we examined the behavioral performance during acute interaction of female adolescent Wistar rats with either age-matched same-strain partners or rats from the Fischer 344 strain. We here identify the low responsiveness upon playful attacks, which appears to be characteristic for social play in the Fischer 344 strain, as one of the main aversive components for adolescent Wistar animals during cross-strain encounters, which subsequently diminishes thermal pain reactivity. A detailed behavioral analysis further revealed increased ultrasonic vocalization at 50kHz and an increased frequency of playful attacks for adolescent Wistar animals paired with a Fischer 344 rat compared to same-strain control pairs. Finally, an acute injection of a subthreshold dose of the cannabinoid type 1 receptor inverse agonist/antagonist SR141716 before the social encounter abolished enhanced play-soliciting behavior in Wistar/Fischer 344 pairs as well as the behavioral consequences of the rejection experience in adolescent Wistar rats, further emphasizing an important modulatory role of the endocannabinoid system in mediating the effects of social behavior and social pain.

Characterisation of (R)-2-(2-Fluorobiphenyl-4-yl)-N-(3-Methylpyridin-2-yl)Propanamide as a Dual Fatty Acid Amide Hydrolase: Cyclooxygenase Inhibitor

Background

Increased endocannabinoid tonus by dual-action fatty acid amide hydrolase (FAAH) and substrate selective cyclooxygenase (COX-2) inhibitors is a promising approach for pain-relief. One such compound with this profile is 2-(2-fluorobiphenyl-4-yl)-N-(3-methylpyridin-2-yl)propanamide (Flu-AM1). These activities are shown by Flu-AM1 racemate, but it is not known whether its two single enantiomers behave differently, as is the case towards COX-2 for the parent flurbiprofen enantiomers. Further, the effects of the compound upon COX-2-derived lipids in intact cells are not known.

Methodology/Principal Findings

COX inhibition was determined using an oxygraphic method with arachidonic acid and 2-arachidonoylglycerol (2-AG) as substrates. FAAH was assayed in mouse brain homogenates using anandamide (AEA) as substrate. Lipidomic analysis was conducted in unstimulated and lipopolysaccharide + interferon γ- stimulated RAW 264.7 macrophage cells. Both enantiomers inhibited COX-2 in a substrate-selective and time-dependent manner, with IC₅₀ values in the absence of a preincubation phase of: (R)-Flu-AM1, COX-1 (arachidonic acid) 6 μM; COX-2 (arachidonic acid) 20 μM; COX-2 (2-AG) 1 μM; (S)-Flu-AM1, COX-1 (arachidonic acid) 3 μM; COX-2 (arachidonic acid) 10 μM; COX-2 (2-AG) 0.7 μM. The compounds showed no enantiomeric selectivity in their FAAH inhibitory properties. (R)-Flu-AM1 (10 μM) greatly inhibited the production of prostaglandin D₂ and E₂ in both unstimulated and lipopolysaccharide + interferon γ- stimulated RAW 264.7 macrophage cells. Levels of 2-AG were not affected either by (R)-Flu-AM1 or by 10 μM flurbiprofen, either alone or in combination with the FAAH inhibitor URB597 (1 μM).

Conclusions/Significance

Both enantiomers of Flu-AM1 are more potent inhibitors of 2-AG compared to arachidonic acid oxygenation by COX-2. Inhibition of COX in lipopolysaccharide + interferon γ- stimulated RAW 264.7 cells is insufficient to affect 2-AG levels despite the large induction of COX-2 produced by this treatment.

Profiling the Oxylipin and Endocannabinoid Metabolome by UPLC-ESI-MS/MS in Human Plasma to Monitor Postprandial Inflammation

Bioactive lipids, including oxylipins, endocannabinoids, and related compounds may function as specific biochemical markers of certain aspects of inflammation. However, the postprandial responsiveness of these compounds is largely unknown; therefore, changes in the circulating oxylipin and endocannabinoid metabolome in response to a challenge meal were investigated at six occasions in a subject who freely modified her usual diet. The dietary change, and especially the challenge meal itself, represented a modification of precursor fatty acid status, with expectedly subtle effects on bioactive lipid levels. To detect even the slightest alteration, highly sensitive ultra-performance liquid chromatography (UPLC) coupled to electrospray ionization (ESI) tandem mass spectrometry (MS/MS) methods for bioactive lipid profiling was employed. A previously validated UPLC-ESI-MS/MS method for profiling the endocannabinoid metabolome was used, while validation of an UPLC-ESI-MS/MS method for oxylipin analysis was performed with acceptable outcomes for a majority of the parameters according to the US Food and Drug Administration guidelines for linearity (0.9938 < R2 < 0.9996), limit of detection (0.0005-2.1 pg on column), limit of quantification (0.0005-4.2 pg on column), inter- and intraday accuracy (85-115%) and precision (< 5%), recovery (40-109%) and stability (40-105%). Forty-seven of fifty-two bioactive lipids were detected in plasma samples at fasting and in the postprandial state (0.5, 1, and 3 hours after the meal). Multivariate analysis showed a significant shift of bioactive lipid profiles in the postprandial state due to inclusion of dairy products in the diet, which was in line with univariate analysis revealing seven compounds (NAGly, 9-HODE, 13-oxo-ODE, 9(10)-EpOME, 12(13)-EpOME, 20-HETE, and 11,12-DHET) that were significantly different between background diets in the postprandial state (but not at fasting). The only change in baseline levels at fasting was displayed by TXB2. Furthermore, postprandial responsiveness was detected for seven compounds (POEA, SEA, 9(10)-DiHOME, 12(13)-DiHOME, 13-oxo-ODE, 9-HODE, and 13-HODE). Hence, the data confirm that the UPLC-ESI-MS/MS method performance was sufficient to detect i) a shift, in the current case most notably in the postprandial bioactive lipid metabolome, caused by changes in diet and ii) responsiveness to a challenge meal for a subset of the oxylipin and endocannabinoid metabolome. To summarize, we have shown proof-of-concept of our UPLC-ESI-MS/MS bioactive lipid protocols for the purpose of monitoring subtle shifts, and thereby useful to address lipid-mediated postprandial inflammation.

Identification of prostamides, fatty acyl ethanolamines, and their biosynthetic precursors in rabbit cornea

Arachidonoyl ethanolamine (anandamide) and pros-taglandin ethanolamines (prostamides) are biologically active derivatives of arachidonic acid. Although available through different precursor phospholipids, there is considerable overlap between the biosynthetic pathways of arachidonic acid-derived eicosanoids and anandamide-derived prostamides. Prostamides exhibit physiological actions and are involved in ocular hypotension, smooth muscle contraction, and inflammatory pain. Although topical application of bimatoprost, a structural analog of prostaglandin F2α ethanolamide (PGF2α-EA), is currently a first-line treatment for ocular hypertension, the endogenous production of prostamides and their biochemical precursors in corneal tissue has not yet been reported. In this study, we report the presence of anandamide, palmitoyl-, stearoyl-, α-linolenoyl docosahexaenoyl-, linoleoyl-, and oleoyl-ethanolamines in rabbit cornea, and following treatment with anandamide, the formation of PGF2α-EA, PGE2-EA, PGD2-EA by corneal extracts (all analyzed by LC/ESI-MS/MS). A number of N-acyl phosphatidylethanolamines, precursors of anandamide and other fatty acyl ethanolamines, were also identified in corneal lipid extracts using ESI-MS/MS. These findings suggest that the prostamide and fatty acid ethanolamine pathways are operational in the cornea and may provide valuable insight into corneal physiology and their potential influence on adjacent tissues and the aqueous humor.

Cannabinoid Receptor-2 Regulates Embryonic Hematopoietic Stem Cell Development via Prostaglandin E2 and P-Selectin Activity

Cannabinoids (CB) modulate adult hematopoietic stem and progenitor cell (HSPCs) function, however, impact on the production, expansion, or migration of embryonic HSCs is currently uncharacterized. Here, using chemical and genetic approaches targeting CB-signaling in zebrafish, we show that CB receptor (CNR) 2, but not CNR1, regulates embryonic HSC development. During HSC specification in the aorta-gonad-mesonephros (AGM) region, CNR2 stimulation by AM1241 increased runx1;cmyb(+) HSPCs, through heightened proliferation, whereas CNR2 antagonism decreased HSPC number; FACS analysis and absolute HSC counts confirmed and quantified these effects. Epistatic investigations showed AM1241 significantly upregulated PGE2 synthesis in a Ptgs2-dependent manner to increase AGM HSCs. During the phases of HSC production and colonization of secondary niches, AM1241 accelerated migration to the caudal hematopoietic tissue (CHT), the site of embryonic HSC expansion, and the thymus; however these effects occurred independently of PGE2. Using a candidate approach for HSC migration and retention factors, P-selectin was identified as the functional target of CNR2 regulation. Epistatic analyses confirmed migration of HSCs into the CHT and thymus was dependent on CNR2-regulated P-selectin activity. Together, these data suggest CNR2-signaling optimizes the production, expansion, and migration of embryonic HSCs by modulating multiple downstream signaling pathways.

The Potential of Inhibitors of Endocannabinoid Metabolism for Drug Development: A Critical Review

The endocannabinoids anandamide and 2-arachidonoylglycerol are metabolised by both hydrolytic enzymes (primarily fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MGL)) and oxygenating enzymes (e.g. cyclooxygenase-2, COX-2). In the present article, the in vivo data for compounds inhibiting endocannabinoid metabolism have been reviewed, focussing on inflammation and pain. Potential reasons for the failure of an FAAH inhibitor in a clinical trial in patients with osteoarthritic pain are discussed. It is concluded that there is a continued potential for compounds inhibiting endocannabinoid metabolism in terms of drug development, but that it is wise not to be unrealistic in terms of expectations of success.

Inhibition of endocannabinoid metabolism by the metabolites of ibuprofen and flurbiprofen

Background

In addition to their effects upon prostaglandin synthesis, the non-steroidal anti-inflammatory drugs ibuprofen and flurbiprofen inhibit the metabolism of the endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide (AEA) by cyclooxygenase-2 (COX-2) and fatty acid amide hydrolase (FAAH), respectively. Here, we investigated whether these effects upon endocannabinoid metabolism are shared by the main metabolites of ibuprofen and flurbiprofen.

Methodology/Principal Findings

COX activities were measured via changes in oxygen consumption due to oxygenation of arachidonic acid (for COX-1) and arachidonic acid and 2-AG (for COX-2). FAAH activity was quantified by measuring hydrolysis of tritium labelled AEA in rat brain homogenates. The ability of ibuprofen and flurbiprofen to inhibit COX-2-catalysed oxygenation of 2-AG at lower concentrations than the oxygenation of arachidonic acid was seen with 4′-hydroxyflurbiprofen and possibly also 3′-hydroxyibuprofen, albeit at lower potencies than the parent compounds. All ibuprofen and flurbiprofen metabolites retained the ability to inhibit FAAH in a pH-dependent manner, although the potency was lower than seen with the parent compounds.

Conclusions/Significance

It is concluded that the primary metabolites of ibuprofen and flurbiprofen retain some of the properties of the parent compound with respect to inhibition of endocannabinoid metabolism. However, these effects are unlikely to contribute to the actions of the parent compounds in vivo.

COX-2-derived endocannabinoid metabolites as novel inflammatory mediators

Cyclooxygenase-2 (COX-2) is an enzyme that plays a key role in inflammatory processes. Classically, this enzyme is upregulated in inflammatory situations and is responsible for the generation of prostaglandins (PGs) from arachidonic acid (AA). One lesser-known property of COX-2 is its ability to metabolize the endocannabinoids, N-arachidonoylethanolamine (AEA) and 2-arachidonoylglycerol (2-AG). Endocannabinoid metabolism by COX-2 is not merely a means to terminate their actions. On the contrary, it generates PG analogs, namely PG-glycerol esters (PG-G) for 2-AG and PG-ethanolamides (PG-EA or prostamides) for AEA. Although the formation of these COX-2-derived metabolites of the endocannabinoids has been known for a while, their biological effects remain to be fully elucidated. Recently, several studies have focused on the role of these PG-G or PG-EA in vivo. In this review we take a closer look at the literature concerning these novel bioactive lipids and their role in inflammation.

Development and validation of a sensitive UPLC-ESI-MS/MS method for the simultaneous quantification of 15 endocannabinoids and related compounds in milk and other biofluids

The endocannabinoid (eCB) system has gained an increasing interest over the past decades since the discovery of anandamide and 2-arachidonoyl glycerol (2-AG). These, and structurally related compounds, are associated with a wide variety of physiological processes. For instance, eCB levels in milk have been associated with infants' feeding and sleeping behavior. A method based on ultraperformance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) was developed and validated for the simultaneous quantification of 15 eCBs and related compounds, including both fatty acid amides and glycerols. Linearity (0.9845 < R(2) < 1), limit of detection and quantification (0.52-293 pg on column), inter- and intraday accuracy (>70%) and precision (CV < 15%), stability, and recovery (in milk and plasma) were established in accordance to the U.S. Food and Drug Administration guidelines. The method was successfully applied to bovine and elk milk revealing species-specific eCB profiles, with significant different levels of 2-AG, 2-linoleoyl glycerol, docosahexaenoyl ethanolamide, palmitoyl ethanolamide, and oleoyl ethanolamide. Furthermore, stearoyl ethanolamide and docosatetraenoyl ethanolamide were only detected in elk milk. In summary, our UPLC-ESI-MS/MS method may be used for quantification of eCBs and related compounds in different biofluids and applied to investigations of the role of these emerging compounds in various physiological processes.

Osteoarthritis of the hand II: chemistry, pharmacokinetics and pharmacodynamics of naproxen, and clinical outcome studies

Objective

This article aims to review osteoarthritis of the hand and the role of the non-steroidal anti-inflammatory drug (NSAID) naproxen on its management. We discuss the chemical and pharmacological properties of naproxen and the NSAID class, with an emphasis on its mechanism and adverse reactions. In the context of part I of this paper in characterizing hand osteoarthritis (OA), we review clinical trials that have been conducted involving hand OA and naproxen.

Key findings

The therapeutic effect of NSAIDs stems from its role on inhibiting cyclo-oxygenase (COX)-1 or COX-2 enzyme activity in the body. These enzymes play a major role in maintaining several functions in the body and due NSAIDs' inhibitory effects; many principle adverse reactions occur with the use of NSAIDs such as: gastrointestinal tract issues, cardiovascular risks, renal, hepatic, central nervous system and cutaneous. Review of clinical trials involving naproxen and hand OA show that it is significantly more efficacious when compared with placebo.

Summary

These studies, along with the finding that naproxen is of least cardiovascular risk in the NSAID class, may show that it can be part of one of the approaches in managing the condition. It is important to note that the optimal NSAID to use varies for each individual. The finding that the use of naproxen leads to the smallest increase in cardiovascular risk appeals to those at-risk individuals who suffer from OA and require pharmacological treatment for relief.

Chiral 1,3,4-oxadiazol-2-ones as highly selective FAAH inhibitors

In the present study, identification of chiral 1,3,4-oxadiazol-2-ones as potent and selective FAAH inhibitors has been described. The separated enantiomers showed clear differences in the potency and selectivity toward both FAAH and MAGL. Additionally, the importance of the chirality on the inhibitory activity and selectivity was proven by the simplification approach by removing a methyl group at the 3-position of the 1,3,4-oxadiazol-2-one ring. The most potent compound of the series, the S-enantiomer of 3-(1-(4-isobutylphenyl)ethyl)-5-methoxy-1,3,4-oxadiazol-2(3H)-one (JZP-327A, 51), inhibited human recombinant FAAH (hrFAAH) in the low nanomolar range (IC50 = 11 nM), whereas its corresponding R-enantiomer 52 showed only moderate inhibition toward hrFAAH (IC50 = 0.24 μM). In contrast to hrFAAH, R-enantiomer 52 was more potent in inhibiting the activity of hrMAGL compared to S-enantiomer 51 (IC50 = 4.0 μM and 16% inhibition at 10 μM, respectively). The FAAH selectivity of the compound 51 over the supposed main off-targets, MAGL and COX, was found to be >900-fold. In addition, activity-based protein profiling (ABPP) indicated high selectivity over other serine hydrolases. Finally, the selected S-enantiomers 51, 53, and 55 were shown to be tight binding, slowly reversible inhibitors of the hrFAAH.

Elevating endocannabinoid levels: pharmacological strategies and potential therapeutic applications

The endocannabinoid system consists of cannabinoid CB1 and CB2 receptors, of endogenous agonists for these receptors known as ‘endocannabinoids’, and of processes responsible for endocannabinoid biosynthesis, cellular uptake and metabolism. There is strong evidence first, that this system up-regulates in certain disorders as indicated by an increased release of endocannabinoids onto their receptors and/or by increases in the expression levels or coupling efficiency of these receptors, and second, that this up-regulation often appears to reduce or abolish unwanted effects of these disorders or to slow their progression. This discovery has raised the possibility of developing a medicine that enhances up-regulation of the endocannabinoid system associated with these disorders by inhibiting the cellular uptake or intracellular metabolism of an endocannabinoid following its ‘autoprotective’ endogenous release. For inhibition of endocannabinoid metabolism, research has focused particularly on two highly investigated endocannabinoids, anandamide and 2-arachidonoyl glycerol, and hence on inhibitors of the main anandamide-metabolising enzyme, fatty acid amide hydrolase (FAAH), and of the main 2-arachidonoyl glycerol-metabolising enzyme, monoacylglycerol (MAG) lipase. The resulting data have provided strong preclinical evidence that selective FAAH and MAG lipase inhibitors would ameliorate the unwanted effects of several disorders, when administered alone or with a cyclooxygenase inhibitor, and that the benefit-to-risk ratio of a FAAH inhibitor would exceed that of a MAG lipase inhibitor or dual inhibitor of FAAH and MAG lipase. Promising preclinical data have also been obtained with inhibitors of endocannabinoid cellular uptake. There is now an urgent need for clinical research with these enzyme and uptake inhibitors.

Identification and characterization of carprofen as a multitarget fatty acid amide hydrolase/cyclooxygenase inhibitor

Pain and inflammation are major therapeutic areas for drug discovery. Current drugs for these pathologies have limited efficacy, however, and often cause a number of unwanted side effects. In the present study, we identify the nonsteroidal anti-inflammatory drug carprofen as a multitarget-directed ligand that simultaneously inhibits cyclooxygenase-1 (COX-1), COX-2, and fatty acid amide hydrolase (FAAH). Additionally, we synthesized and tested several derivatives of carprofen, sharing this multitarget activity. This may result in improved analgesic efficacy and reduced side effects (Naidu et al. J. Pharmacol. Exp. Ther.2009, 329, 48-56; Fowler, C. J.; et al. J. Enzyme Inhib. Med. Chem.2012, in press; Sasso et al. Pharmacol. Res.2012, 65, 553). The new compounds are among the most potent multitarget FAAH/COX inhibitors reported so far in the literature and thus may represent promising starting points for the discovery of new analgesic and anti-inflammatory drugs.