Pharmacological investigation of trimetazidine in models of inflammation, pain and gastric injury in rodents

Deciphering the therapeutic potential of trimetazidine in rheumatoid arthritis via targeting mi-RNA128a, TLR4 signaling pathway, and adenosine-induced FADD-microvesicular shedding: In vivo and in silico study

Rheumatoid arthritis (RA) is a debilitating autoimmune condition characterized by chronic synovitis, joint damage, and inflammation, leading to impaired joint functionality. Existing RA treatments, although effective to some extent, are not without side effects, prompting a search for more potent therapies. Recent research has revealed the critical role of FAS-associated death domain protein (FADD) microvesicular shedding in RA pathogenesis, expanding its scope beyond apoptosis to include inflammatory and immune pathways. This study aimed to investigate the intricate relationship between mi-RNA 128a, autoimmune and inflammatory pathways, and adenosine levels in modulating FADD expression and microvesicular shedding in a Freund's complete adjuvant (FCA) induced RA rat model and further explore the antirheumatoid potency of trimetazidine (TMZ). The FCA treated model exhibited significantly elevated levels of serum fibrogenic, inflammatory, immunological and rheumatological diagnostic markers, confirming successful RA induction. Our results revealed that the FCA-induced RA model showed a significant reduction in the expression of FADD in paw tissue and increased microvesicular FADD shedding in synovial fluid, which was attributed to the significant increase in the expression of the epigenetic miRNA 128a gene in addition to the downregulation of adenosine levels. These findings were further supported by the significant activation of the TLR4/MYD88 pathway and its downstream inflammatory IkB/NFB markers. Interestingly, TMZ administration significantly improved, with a potency similar to methotrexate (MTX), the deterioration effect of FCA treatment, as evidenced by a significant attenuation of fibrogenic, inflammatory, immunological, and rheumatological markers. Our investigations indicated that TMZ uniquely acted by targeting epigenetic miRNA128a expression and elevating adenosine levels in paw tissue, leading to increased expression of FADD of paw tissue and mitigated FADD microvesicular shedding in synovial fluid. Furthermore, the group treated with TMZ showed significant downregulation of TLR4/MYD88 and their downstream TRAF6, IRAK and NF-kB. Together, our study unveils the significant potential of TMZ as an antirheumatoid candidate, offering anti-inflammatory effects through various mechanisms, including modulation of the FADD-epigenetic regulator mi-RNA 128a, adenosine levels, and the TLR4 signaling pathway in joint tissue, but also attenuation of FADD microvesicular shedding in synovial fluid. These findings further highlight the synergistic administration of TMZ and MTX as a potential approach to reduce adverse effects of MTX while improving therapeutic efficacy.

Enhanced healing efficacy of an optimized gabapentin-melittin nanoconjugate gel-loaded formulation in excised wounds of diabetic rats

The present study aimed to design and optimize, a nanoconjugate of gabapentin (GPN)-melittin (MLT) and to evaluate its healing activity in rat diabetic wounds. To explore the wound healing potency of GPN-MLT nanoconjugate, an in vivo study was carried out. Diabetic rats were subjected to excision wounds and received daily topical treatment with conventional formulations of GPN, MLT, GPN-MLT nanoconjugate and a marketed formula. The outcome of the in vivo study showed an expedited wound contraction in GPN-MLT-treated animals. This was confirmed histologically. The nanoconjugate formula exhibited antioxidant activities as evidenced by preventing malondialdehyde (MDA) accumulation and superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymatic exhaustion. Further, the nanoconjugate showed superior anti-inflammatory activity as it inhibited the expression of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). This is in addition to enhancement of proliferation as indicated by increased expression of transforming growth factor-β (TGF- β), vascular endothelial growth factor-A (VEGF-A) and platelet-derived growth factor receptor-β (PDGFRB). Also, nanoconjugate enhanced hydroxyproline concentration and mRNA expression of collagen type 1 alpha 1 (Col 1A1). In conclusion, a GPN-MLT nanoconjugate was optimized with respect to particle size. Analysis of pharmacokinetic attributes showed the mean particle size of optimized nanoconjugate as 156.9 nm. The nanoconjugate exhibited potent wound healing activities in diabetic rats. This, at least partly, involve enhanced antioxidant, anti-inflammatory, proliferative and pro-collagen activities. This may help to develop novel formulae that could accelerate wound healing in diabetes.

Trimetazidine, an Anti-Ischemic Drug, Reduces the Antielectroshock Effects of Certain First-Generation Antiepileptic Drugs

Trimetazidine (TMZ), an anti-ischemic drug for improving cellular metabolism, is mostly administered to patients with poorly controlled ischemic heart disease (IHD). Since IHD is considered the most frequent causative factor of cardiac arrhythmias, and these often coexist with seizure disorders, we decided to investigate the effect of TMZ in the electroconvulsive threshold test (ECT) and its influence on the action of four first-generation antiepileptic drugs in the maximal electroshock test (MES) in mice. The TMZ (up to 120 mg/kg) did not affect the ECT, but applied at doses of 20–120 mg/kg it decreased the antielectroshock action of phenobarbital. The TMZ (50–120 mg/kg) reduced the effect of phenytoin, and, when administered at a dose of 120 mg/kg, it diminished the action of carbamazepine. All of these revealed interactions seem to be pharmacodynamic, since the TMZ did not affect the brain levels of antiepileptic drugs. Furthermore, the combination of TMZ with valproate (but not with other antiepileptic drugs) significantly impaired motor coordination, evaluated using the chimney test. Long-term memory, assessed with a passive-avoidance task, was not affected by either the TMZ or its combinations with antiepileptic drugs. The obtained results suggest that TMZ may not be beneficial as an add-on therapy in patients with IHD and epilepsy.

Trimetazidine attenuates cyclophosphamide-induced cystitis by inhibiting TLR4-mediated NFκB signaling in mice

AIM

Cyclophosphamide (CP)-induced cystitis is a challenging clinical problem involving inflammation and dysfunction of bladder. Trimetazidine (TMZ) is an anti-anginal drug with anti-oxidant and anti-inflammatory properties. We aimed to investigate the protective effects of TMZ in CP-induced cystitis via inhibiting TLR4/NFκB signaling.

MAIN METHODS

Balb/c mice were administrated TMZ (10 or 20 mg/kg/day) intraperitoneally (i.p.) for 5 consecutive days before CP. On day 6, cystitis was induced by a single dose of CP (300 mg/kg, i.p.). Mesna (2-mercaptoethane sulfonate sodium; 30 mg/kg, i.p.) was administered 20 min before and at 4 and 8 h after the CP injection. After 24 h of cystitis induction, the bladders were removed for histopathological evaluation, contractility studies, biochemical analysis and western blotting. MTT assay was performed in a cancer cell line (MDA-MB-231) to evaluate the effect of TMZ on the cytotoxicity of CP.

KEY FINDINGS

CP-induced severe cystitis was confirmed by histological disturbances and the decrease in carbachol-evoked contractions of detrusor strips, which was partially improved by TMZ (20 mg/kg/day). SOD activity and GSH content were decreased whereas TNF-α and IL-1β levels were increased in the bladders of CP-treated mice, which were restored by TMZ or mesna. TMZ reduced the CP-induced increase in the protein expressions of caspase-3, TLR4 and phosphorylated-NFκB in bladder tissues. TMZ alone decreased the cell viability and TMZ also enhanced the cytotoxicity of CP.

SIGNIFICANCE

Our study provides the first preclinical evidence that TMZ attenuates CP-induced urotoxicity by enhancing anti-oxidant capacity and suppressing inflammation possibly via downregulating TLR4-mediated NFκB signaling while augmenting the cytotoxicity of CP.

Enhancement of the Anti-Inflammatory Activity of NSAIDs by Their Conjugation with 3,4,5-Trimethoxybenzyl Alcohol

The synthesis of derivatives of three nonspecific COX-1 and COX-2 inhibitors, ibuprofen, ketoprofen, naproxen is presented. These acids were connected via an amide bond with an amino acid (L-proline, L-tyrosine, and beta-alanine) used as a linker. The amino acid carboxylic group was esterified with 3,4,5 trimethoxybenzyl alcohol. The activity of the novel derivatives was examined in vivo on carrageenan-induced inflammation, and in vitro, as cyclooxygenase and lipoxygenase inhibitors. It was found that the new compounds were more potent anti-inflammatory agents than the parent drugs. Thus, the ibuprofen (21) and ketoprofen (16) derivatives reduced rat paw edema by 67 and 91% (the reduction by the relevant NSAIDs was 36 and 47%, respectively). They inhibited COX-2 more than the starting drugs (21 by 67%, ibuprofen 46%, 19 by 94%, ketoprofen 49%). Docking of compounds on the active sites of COX-1 and COX-2 reflects their in vitro activity. Thus, 19 adopts an unfavorable orientation for COX-1 inhibition, but it binds effectively in the binding pocket of COX-2, in agreement with the absence of activity for COX-1 and the high inhibition of COX-2. In conclusion, the performed structural modifications result in the enhancement of the anti-inflammatory activity, compared with the parent NSAIDs.

Synthesis and Antinociceptive Effect of Some Thiazole-Piperazine Derivatives: Involvement of Opioidergic System in the Activity

In this study, we aimed to design and synthesize novel molecules carrying both the thiazole and piperazine rings in their structures and to investigate their antinociceptive activity. Targeted compounds were obtained by reacting thiosemicarbazide derivative and appropriate 2-bromoacetophenone in ethanol. The structures of the obtained compounds were determined using data from various spectroscopic methods (IR, ¹H-NMR, ¹³C-NMR, and LCMSMS). Experimental data from in vivo tests showed that test compounds 3a–3c, 3f, and 3g (50 mg/kg) significantly prolonged reaction times of animals in tail-clip and hot-plate tests compared to the controls, indicating that these compounds possess centrally mediated antinociceptive activities. Furthermore, these compounds reduced the number of writhing behaviors in the acetic acid-induced writhing tests, showing that the compounds also possess peripheral antinociceptive activity. In the mechanistic studies, naloxone pre-treatments abolished the antinociceptive activities of compounds 3a–3c, 3f, and 3g, indicating that opioidergic mechanisms were involved in their antinociceptive effects. Molecular docking studies demonstrating significant interactions between the active compounds and µ- and δ-opioid receptor proteins supported the pharmacological findings. This study is the first showing that molecules designed to bear thiazole and piperazine moieties together on their structure exert centrally and peripherally mediated antinociceptive effects by activating the opioid system.

5-HT1A Serotonergic, α-Adrenergic and Opioidergic Receptors Mediate the Analgesic Efficacy of Vortioxetine in Mice

Vortioxetine is a multimodal antidepressant drug that affects several brain neurochemicals and has the potential to induce various pharmacological effects on the central nervous system. Therefore, we investigated the centrally mediated analgesic efficacy of this drug and the mechanisms underlying this effect. Analgesic activity of vortioxetine (5, 10 and 20 mg/kg, p.o.) was examined by tail-clip, tail-immersion and hot-plate tests. Motor performance of animals was evaluated using Rota-rod device. Time course measurements (30-180 min) showed that vortioxetine (10 and 20 mg/kg) administrations significantly increased the response latency, percent maximum possible effect and area under the curve values in all of the nociceptive tests. These data pointed out the analgesic effect of vortioxetine on central pathways carrying acute thermal and mechanical nociceptive stimuli. Vortioxetine did not alter the motor coordination of mice indicating that the analgesic activity of this drug was specific. In mechanistic studies, pre-treatments with p-chlorophenylalanine (serotonin-synthesis inhibitor), NAN-190 (serotonin 5-HT_1A receptor antagonist), α-methyl-para-tyrosine (catecholamine-synthesis inhibitor), phentolamine (non-selective α-adrenoceptor blocker), and naloxone (non-selective opioid receptor blocker) antagonised the vortioxetine-induced analgesia. Obtained findings indicated that vortioxetine-induced analgesia is mediated by 5-HT_1A serotonergic, α-adrenergic and opioidergic receptors, and contributions of central serotonergic and catecholaminergic neurotransmissions are critical for this effect.

Experimental Evaluation of Anxiolytic and Analgesic Properties of a New Linear Methoxyphenyltriazaalkane Derivative with Cardiotropic Activity

The anxiolytic and analgesic properties of compound ALM-802, a cardiotropic linear methoxyphenyltriazaalkane derivative, combining pharmacophore elements of p-FOX inhibitors trimetazidine and ranolazine were studied in vivo. In the elevated plus-maze test, ALM-802 after acute intraperitoneal administration in doses of 1-8 mg/kg dose-dependently prevented the development of anxiety in BALB/c mice. Chronic intraperitoneal administration of ALM-802 in a dose of 2 mg/kg to alcohol-preferring rats attenuated anxiogenesis induced by ethanol withdrawal. ALM-802 demonstrated antinociceptive activity in C57BL/6 mice during thermal stimulation of nociceptors in the hot plate test and during modeling of visceral pain in the acetic acid writhing test. Thus, ALM-802 exhibits anxiolytic and analgesic properties in the dose range corresponding to its anti-ischemic and antiarrhythmic effects.

Antinociceptive effect of ranolazine and trimetazidine

Background:Ranolazine and trimetazidine are piperazine derivatives used in antianginal therapy. There are data on the use of these drugs in the treatment of neuropathic pain. In this study, it was aimed to evaluate the antinociceptive effects of ranolazine and trimetazidine.Methods: Sixty patients who were started on trimetazidine or ranolazine treatment were included in the study. The patients were evaluated with Seattle Angina Questionnaire (SAQ), Visual Analog Scale (VAS) and State-Trait Anxiety Inventory (STAI) on the first day of treatment and at the first month follow-up.Results: The SAQ scores of the patients given ranolazine were statistically significantly higher than the patients given trimetazidine. The most significant increase was observed in terms of treatment satisfaction (53.03 ± 8.11 vs. 72.88 ± 5.29, p < 0.001) and quality of life (49.79 ± 8.62 vs. 68.01 ± 0.65, p = 0.016). The decrease in VAS (p = 0.001) and the decrease in STAI scores (p = 0.002) after treatment in the ranolazine group were significantly higher than in the trimetazidine group.Conclusions: Ranolazine and trimetazidine are two effective drugs in antianginal treatment. While both drugs are effective on general systemic musculoskeletal pain and anxiety, the efficacy of ranolazine is more pronounced.

The Use of Pistacia Lentiscus Chia Resin Versus Omeprazole in Protecting Male Rats Peptic Mucosa Against Cold Restraint Stress

Introduction

Peptic mucosal damage induced by acute stress is a serious cause of morbidity and mortality in critically ill patients. The study aimed to investigate the protective, antioxidant and anti-inflammatory effects of pretreatment with Chios mastic gum (CMG), a traditionally consumed herbal resin naturally deriving from the trunk of Pistacia Lentiscus var. Chia compared to Omeprazole, a standard medication used in the prevention and treatment of gastritis, against the effects of cold restraint stress (CRS) in rat gastric and colonic mucosa.

Methods

Twenty-one male Wistar rats were randomly assigned to three groups: Control (C), Omeprazole (O), and CMG (M), according to the pre-treatment regime, and were subjected to CRS at 4⁰C for 3 hours. The gastric and colonic mucosal lesions were histologically assessed. ELISA measured blood concentrations of TNF-α, IL-1β, peroxidase, superoxide dismutase (SOD) and total antioxidant capacity (TEAC).

Results

In both groups, O and M, gastric mucosal hyperemia, haemorrhagic infiltration and mucosal oedema, as well as colonic mucosal hyperaemia and haemorrhagic infiltration were significantly reduced compared to the controls (p<0.05). No significant differences were observed between Groups O and M. TNF-α levels were significantly lower in group M compared to Group O (p=0.013). IL-1β levels were significantly depressed in groups M and O compared to control (p≤ 0.001). The activity of both peroxidase and SOD enzymes decreased in group M compared to group O (p= 0.043 and p=0.047 respectively) and the control (p=0.018 and p< 0.001 respectively).

Conclusions

The natural Chios mastic gum is a promising nutritional supplement with protective properties to the peptic mucosa against CRS, exerting anti-inflammatory and antioxidant effects.

An in vivo and in vitro assessment of the anti-inflammatory, antinociceptive, and immunomodulatory activities of Clematis terniflora DC. extract, participation of aurantiamide acetate

AIM

Clematis terniflora DC. has been widely used as a traditional Chinese medicine for the treatment of tonsillitis, rheumatoid arthritis, and prostatitis. Despite its widespread use in China, there are currently no studies systematically examined its therapeutic effects and mechanism of action. As such, the present study was conducted to evaluate the anti-inflammatory, antinociceptive, and immunomodulatory effects of C. terniflora DC. using rodent and cellular models.

METHODS

The anti-inflammatory properties of the 70% ethanol eluted fraction of the 70% ethanol extract of C. terniflora DC. (EECTD) were evaluated using the xylene-induced ear swelling test, the carrageenan-induced edema model, and the cotton pellet granuloma method. Its antinociceptive activities were determined using both the acetic acid-induced writhing test and the hot plate assay. In parallel, we conducted an in vitro assay in LPS-induced RAW264.7 cells to examine the anti-inflammatory effects of EECTD and its purified form, aurantiamide acetate (AA) on inhibition of nitric oxide (NO) and prostaglandin E2 (PGE2) release.

RESULTS

EECTD (300mg/kg) significantly reduced the number of writhing, extended the pain response latency, and suppressed xylene-induced ear swelling. Each EECTD treatment group also had significant inhibition of cotton granulation formation in addition to reduced carrageenan-induced paw edema. EECTD was also shown to alleviate signs of inflammation in histopathological paw sections. However, it had a less noticeable effect on mouse ear swelling in the delayed type hypersensitivity test. A purified compound was isolated from EECTD and its structure was identified as AA. In vitro experimental results showed that both EECTD and AA were able to significantly inhibit the release of pro-inflammatory cytokines NO and PGE2 on LPS-induced RAW264.7 cells.

CONCLUSION

These results suggest that EECTD has significant anti-inflammatory and antinociceptive activities, partially related to one of the active substances identified as AA. We hypothesize that these effects are related to its ability to inhibit the production of cytokines NO and PGE2. However, further work will be needed to determine its exact mechanism of action.

Endogenous opiates and behavior: 2005

This paper is the 28th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2005 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity, neurophysiology and transmitter release (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); immunological responses (Section 17).

Synthesis, Acute Toxicity, and Analgesic Activity of New Derivatives of Pyrrole

Ten pyrrole derivatives (including six new compounds) were synthesized and evaluated as potential platform for analgesic agents' development. Acute intraperitoneal toxicity and analgesic activity studies (acetic acid writhing test) were performed on mice with acetylsalicylic acid used as a reference substance. Products 3c, 3d, 3e, and 3h exhibited a dose-dependent activity demonstrating 1.5 to 2.5-fold better protections than the reference. The most prospective compounds comprised salicylic acid moieties, whose 4-substituted derivatives were related to lower acute toxicity and considerable activity. 4-[3-(Ethoxycarbonyl)-2-methyl-5-(3,4-dimethoxy-phenyl)-1H-pyrrol-1-yl]-2-hydroxy-benzoic acid 3c was pointed out as the most prospective substance due to its lower acute toxicity (378 mg/kg body weight, intraperitoneally) and highest analgesic activity (up to 89.3% protection) in a dose range of 1/10 to 1/40 parts of LD(50).