Pregabalin inhibits in vivo and in vitro cytokine secretion and attenuates spleen inflammation in Lipopolysaccharide/Concanavalin A -induced murine models of inflammation

New Pharmacological Insight into Etanercept and Pregabalin in Allodynia and Nociception: Behavioral Studies in a Murine Neuropathic Pain Model

Background/Objectives: Neuropathic pain is challenging to treat, often resistant to current therapies, and associated with significant side effects. Pregabalin, an anticonvulsant that modulates calcium channels, is effective but can impair mental and motor functions, especially in older patients. To improve patient outcomes, reducing the doses of pregabalin and combining it with other drugs targeting different neuropathic pain mechanisms may be beneficial. TNF-α blockers such as etanercept have shown potential in addressing neuropathic pain by affecting sodium channels, synaptic transmission, and neuroinflammation. This study evaluates the efficacy and safety of combining low doses of etanercept and pregabalin in allodynia and nociceptive tests. Materials and Methods: Male C57/BL6 mice underwent chronic constriction injury (CCI) of the sciatic nerve to induce neuropathic pain. They were divided into seven groups: sham control, CCI control, low and high doses of pregabalin, low and high doses of etanercept, and a combination of low doses of both drugs. Behavioral tests, including von Frey, hot-plate, and rotarod tests, were used to assess pain responses and motor activity. Results: The results indicated that a high dose of pregabalin significantly reduced mechanical allodynia and thermal hyperalgesia but impaired motor function. Conversely, low doses of etanercept alone had no significant effect. However, the combination of low doses of etanercept (20 mg/kg) and pregabalin (5 mg/kg) effectively alleviated pain without compromising locomotor activity. Conclusions: These results suggest a novel therapeutic strategy for neuropathic pain, enhancing analgesic efficacy while minimizing adverse effects.

Characterization and Evaluation of the Cytotoxicity of Pregabalin Gels for Oral Application

The efficacy of pregabalin in pain treatment has led to the search for new formulations for its use through different routes of administration. This study aimed to prepare, characterize, and evaluate the cytotoxicity of pregabalin (PG) gels for topical application in the oral cavity. Solutions with three different concentrations of PG were prepared and added to a 1.0% carbopol gel base. Thermal analyses (TG and DSC) and FTIR were performed on the gel and pure pregabalin. Stability (preliminary and accelerated) and rheology studies were also conducted on the gels. Cytotoxicity was evaluated in human gingival fibroblasts in the following groups: WG (1.0% carbopol gel base), PG2G (2.0% pregabalin gel), PG5G (5.0% pregabalin gel), and PG10G (10% pregabalin gel). A transparent and homogeneous gel with a pH of 6 was obtained. The formulations showed stability, and the different drug concentrations did not influence the product's characteristics. None of the tested groups showed cytotoxicity for the analyzed cells. The pregabalin gels exhibited favorable and non-toxic characteristics for human gingival fibroblasts in vitro. Therefore, this product may be a promising therapeutic alternative for topical application in the oral mucosa.

Ameliorative effect of nano-pregabalin in gastrocnemius muscle of gamma irradiated rats with an experimental model of fibromyalgia: Crosstalk of Sirt3, IL-1β and PARP1 pathways

BACKGROUND

Fibromyalgia (FM) is a complex syndrome with somatic symptoms connected to the operational state of muscles. Although radiotherapy is a cornerstone in cancer treatment, it is implicated in the aggravation of FM. Lately, formulation of medicines in nano-forms become of great prominence due to their prospective applications in medicine. So, this study aimed to assess possible therapeutic benefits of formulating pregabalin in a nono-form (N-PG) for managing FM during exposure to gamma radiation.

METHODS

Gamma rays administered in fractionated doses (2 Gy/day) to male rats after one hour of s.c. injection of reserpine (1 mL/kg per day) to induce FM, then treated with single daily dose of (30 mg/kg, p.o.) PG or N-PG for ten successive days. Rats were subjected to behavioral tests, then sacrificed to obtain serum and gastrocnemius muscles.

RESULTS

N-PG significantly antagonized reserpine-induced FM as proved by; the immobility and performance times in forced swim and rotarod performance tests, respectively were restored near to the normal time, serum IL-8 and MCP-1 chemokines were nearby the normal levels, mitigated oxidative stress through increasing total thiol, Sirt3, CAT enzyme and decreasing COX-1, inhibition of inflammation via IL-1β and MIF significant reduction, it possessed anti-apoptotic effect verified by decreasing PARP-1 and increasing Bcl-XL, gastrocnemius muscles had minimal fibrosis levels as seen after Masson trichrome staining. Histopathological results were coincidence with biochemical inspection.

CONCLUSION

This study identifies N-PG as a novel drug that could be of a value in the management of FM particularly in cancer patients undergoing radiotherapy.

Low Dose Pregabalin Improves Gastrointestinal Symptoms of Crohn's Disease

Inflammatory bowel diseases (IBD), including Crohn's disease and ulcerative colitis, are lifelong conditions with no definite cure. Several studies demonstrated that patients with IBD more frequently experience symptoms of common mental disorders, such as anxiety and depression, because of bidirectional communication through the gut-brain axis and the chronicity of symptoms, as well as because of impaired quality of life and reduced social functioning. However, psychological conditions of affected patients are often underestimated and not fully considered. Herein, we present the case of a 37-year-old woman with Crohn's disease and a mild depressive condition, characterized by anxious distress, tachycardia, tachypnea, tremors, sweating, avoidant behaviors, and intestinal somatizations (diarrhea), who was treated with Pregabalin upon indication of the referring psychiatrist. Following the beginning of the treatment, the patient rapidly reported an improvement in the overall clinical symptoms as well as a better management of psychic and physical anxiety with a marked reduction in diarrheal discharges under stress at work. After 6 months of Pregabalin therapy, we additionally observed an improvement in Crohn's disease activity, both clinically, in the laboratory, and endoscopically. Our case showed that patients with Crohn's disease and anxiety problems may benefit from low-dose Pregabalin medication to improve both their mental and physical condition.

Antibody-Conjugated Magnetic Nanoparticle Therapy for Inhibiting T-Cell Mediated Inflammation

Tolerance induction is critical for mitigating T cell-mediated inflammation. Treatments based on anti-CD3 monoclonal antibody (mAb) play a pivotal role in inducing such tolerance. Anti-CD3 mAb conjugated with dextran-coated magnetic nanoparticles (MNPs) may induce inflammatory tolerance is posited. MNPs conjugated with anti-CD3 mAb (Ab-MNPs) are characterized using transmission and scanning electron microscopy, and their distribution is assessed using a nanoparticle tracking analyzer. Compared to MNPs, 90% of Ab-MNPs increased in size from 54.7 ± 0.5 to 71.7 ± 2.7 nm. The in vitro and in vivo studies confirmed the therapeutic material as nontoxic and biocompatible. Mice are administered various dosages of Ab-MNPs before receiving concanavalin-A (ConA), an inflammation inducer. Preadministration of Ab-MNPs, as opposed to MNPs or anti-CD3 mAb alone, significantly reduced the serum levels of interferon-γ and interleukin-6 in ConA-treated mice. Additionally, the transdermal stamp patch as an effective delivery system for Ab-MNPs is validated. This study demonstrates the utility of the Ab-MNP complex in pathologies associated with T cell-mediated hyperinflammation, such as organ transplantation and COVID-19.

Protective effect of pregabalin on renal and renal endothelial damage in sepsis induced by lipopolysaccharide

OBJECTIVE

We investigated the protective effects of pregabalin (PRG) on kidney and renal endothelial damage in sepsis induced by Lipopolysaccharide (LPS).

MATERIALS AND METHODS

Rats were randomly divided into three groups as control, LPS and LPS+PRG. Saline solution was administered 30 mg/kg orally and 5 mg/kg intraperitoneally (i.p.) to the control group. LPS was applied as 5 mg/kg, i.p. to the LPS group. In the LPS+PRG group, PRG at 30 mg/kg orally and one hour before LPS administration, one hour later 5 mg/kg i.p. LPS was applied. Rats were sacrificed 6 hours after LPS administration.

RESULTS

White Blood Cell (WBC), granulocyte, Blood Urea Nitrogen (BUN), creatinine, uric asid, Total Oxidant Status (TOS) and Oxidative Stress Index (OSI) significantly increased (p<0.05); platelets (PLT), activated partial thromboplastin time (aPTT) and Total Antioxidant Status (TAS) significantly decreased in the LPS group compared to the control group (p<0.05). In the LPS+PRG group WBC, granulocyte, BUN, creatinine, uric asid, TOS and OSI significantly decreased (p<0.05); PLT, aPTT and TAS significantly increased compared to the LPS group(p<0.05). Histopathological examinations showed that kidney and renal endothelial damage in the LPS group decreased in the LPS+PRG group. Immunohistochemically IL1-β, IL-6, IL-10, TNF-α expressions in kidney tissue and Toll-Like Receptors-4 (TLR-4) and NF-κB expressions in the renal endothelial tissue significantly increased in the LPS group compared to the control group and significantly decreased in the LPS+PRG group compared to the LPS group (p<0.001).

CONCLUSIONS

Sepsis causes kidney and renal endothelial damage and PRG reduces this damage. Therefore PRG can be used in prophylactic treatment in sepsis, supported by more studies.

Mirogabalin improves cancer-associated pain but increases the risk of malignancy in mice with pancreatic cancer

ABSTRACT

Mirogabalin, a selective voltage-gated calcium channel α2δ ligand, improves peripheral neuropathic pain; however, its effects on patients with cancers including pancreatic ductal adenocarcinoma (PDAC) remain unknown. We analyzed the effects of mirogabalin on a KPPC ( LSL-KrasG12D/+; Trp53flox/flox; Pdx-1cre/+ ) mouse model of PDAC. Six-week-old KPPC mice received oral mirogabalin (10 mg/kg/day) (n = 10) or vehicle water (n = 14) until the humane end point. Cancer-associated pain was evaluated using the scores of hunching and mouse grimace scale (MGS). Tumor status and plasma cytokine levels were determined using histopathological analysis and cytokine array, respectively. The effects of mirogabalin on the proliferative ability of PDAC cell lines were determined. The scores of the hunching and MGS improved after mirogabalin administration with a decrease in the plasma levels of inflammatory cytokines, such as tumor necrosis factor-α, interleukin-6, and interferon-γ. Although no significant difference in the survival rate was observed, mirogabalin significantly increased pancreatic tumor size and proliferative index of Ki-67 and cyclins. Local arginase-1 + M2-like tumor-associated macrophages and CD31 + tumor blood vessels increased after mirogabalin administration. By contrast, the number of α-smooth muscle actin + cancer-associated fibroblasts, desmoplastic stroma, and CD8 + T cells decreased. Local myeloperoxidase + tumor-associated neutrophils and CD45R + B cells were unaltered. Mirogabalin enhanced the proliferative ability of PDAC cell lines with the upregulation of cyclins and cyclin-dependent kinases; however, it inhibited the potential of pancreatic stellate cells in vitro. Therefore, our results suggest that mirogabalin improves cancer-associated pain but enhances the proliferative potential of PDAC in vitro and in vivo.

Pregabalin inhibits proinflammatory cytokine release in patients with fibromyalgia syndrome

Objectives

The main goal of the study was to investigate how pregabalin (PGB) affects proinflammatory cytokine release in patients with fibromyalgia syndrome (FMS).

Patients and methods

This experimental research study was conducted with 85 female participants (mean age: 49.6±10.1 years; range, 30 to 73 years) between April 2020 and November 2020. Of the participants, 30 were FMS patients using PGB 150 mg/day for at least three months, 30 were FMS patients not using PGB, and 25 were healthy individuals. The detection of FMS was carried out according to the 2010 American College of Rheumatology diagnostic criteria. Levels of proinflammatory cytokines (interleukin [IL]-2, IL-6, IL-12, IL-17, interferon-gamma, and tumor necrosis factor-alpha) were measured by enzyme-linked immunosorbent assay.

Results

Serum concentrations of proinflammatory cytokines were remarkably decreased in FMS patients using PGB (p<0.001) and were higher in patients with FMS not using PGB than in healthy subjects (p<0.001). The highest values of proinflammatory cytokines were found in the group of FMS patients not using PGB (p<0.001).

Conclusion

These results indicate that PGB inhibits the release of proinflammatory cytokines, suggesting that it can be used as an anti-inflammatory agent in inflammatory cases.

Structural characterization of a sulfated polysaccharide from Ishige okamurae and its effect on recovery from immunosuppression

A sulfated polysaccharide from the brown alga Ishige okamurae Yendo, designated IOY, was successfully isolated by anion-exchange and size-exclusion chromatography. Chemical and spectroscopic analyses demonstrated that IOY was a fucoidan, that consisted of →3)-α-l-Fucp-(1→, →4)-α-l-Fucp-(1→, →6)-β-d-Galp-(1 → and →3)-β-d-Galp-(1 → residues with sulfate groups at C-2/C-4 the of (1 → 3)-α-l-Fucp and C-6 the of (1 → 3)-β-d-Galp residues. IOY possessed a potent immunomodulatory effect in vitro as measured by lymphocyte proliferation assay. The immunomodulatory effect of IOY was further investigated in vivo using immunosuppressed mice induced by cyclophosphamide (CTX). The results showed that IOY significantly increased the spleen and thymus indexes and alleviated CTX-induced spleen and thymus damage. Furthermore, IOY had a significant effect on hematopoietic function recovery and promoted the secretion of interleukin-2 (IL-2) and tumor necrosis factor (TNF-α). Notably, IOY reversed CD4+ and CD8+ T cell reduction and improved immune response. These data indicated that IOY had vital in immunomodulatory function and could be used as drug or functional food to lessen chemotherapy-induced immunosuppression.

Response profile in a rat model of exercise-induced hypoalgesia is associated with duloxetine, pregabalin and diclofenac effect on constriction-induced neuropathy

BACKGROUND

Exercise is a known trigger of the inhibitory pain modulation system and its analgesic effect is termed exercise-induced hypoalgesia (EIH). Previous studies have demonstrated that rats with deficient analgesic response following exercise develop more significant hypersensitivity following nerve injury compared to rats with substantial analgesic response following exercise.

OBJECTIVES

A rat model of EIH as an indicator of the pain inhibitory system's efficiency was used to explore the association between EIH profiles and the effect of pharmacotherapy on rat's neuropathic pain.

METHODS

EIH profiles were assessed by evaluating paw responses to mechanical stimuli before and after exercise on a rotating rod. Rats with a reduction of ≤33% in responses were classified as low EIH and those with ≥67% as high EIH. Low and high EIH rats underwent sciatic nerve chronic constriction injury (CCI). Paw responses to mechanical stimuli were measured at baseline, following CCI, and after treatment with diclofenac, duloxetine or pregabalin. In a different group of low and high EIH rats, EIH was measured before and following treatment with the same medications.

RESULTS

Low EIH rats developed more significant hypersensitivity following CCI. Duloxetine and pregabalin successfully reduced hypersensitivity, although significantly more so in low EIH rats. Diclofenac had limited effects, and only on low EIH rats. Four days of duloxetine administration transformed low EIH rats' profiles to high EIH.

CONCLUSIONS

The findings of this study suggest that EIH profiles in rats can not only predict the development of hypersensitivity following injury but may also support targeted pharmacological treatment.

SIGNIFICANCE

Exercise is a known trigger of the inhibitory pain modulation. Rats with deficient analgesic response following exercise develop more significant hypersensitivity following nerve injury. Pain modulation profiles in rats can also support targeted pharmacological treatment; rats with deficient analgesic response following exercise benefit more from treatment with duloxetine and gabapentin. Treatment with duloxetine can improve pain modulation profile.

American ginseng with different processing methods ameliorate immunosuppression induced by cyclophosphamide in mice via the MAPK signaling pathways

This study aimed to clarify the effects of two processed forms of American ginseng (Panax quinquefolius L.) on immunosuppression caused by cyclophosphamide (CTX) in mice. In the CTX-induced immunosuppressive model, mice were given either steamed American ginseng (American ginseng red, AGR) or raw American ginseng (American ginseng soft branch, AGS) by intragastric administration. Serum and spleen tissues were collected, and the pathological changes in mice spleens were observed by conventional HE staining. The expression levels of cytokines were detected by ELISA, and the apoptosis of splenic cells was determined by western blotting. The results showed that AGR and AGS could relieve CTX-induced immunosuppression through the enhanced immune organ index, improved cell-mediated immune response, increased serum levels of cytokines (TNF-α, IFN-γ, and IL-2) and immunoglobulins (IgG, IgA, and IgM), as well as macrophage activities including carbon clearance and phagocytic index. AGR and AGS downregulated the expression of BAX and elevated the expression of Bcl-2, p-P38, p-JNK, and p-ERK in the spleens of CTX-injected animals. Compared to AGS, AGR significantly improved the number of CD4⁺CD8^-T lymphocytes, the spleen index, and serum levels of IgA, IgG, TNF-α, and IFN-γ. The expression of the ERK/MAPK pathway was markedly increased. These findings support the hypothesis that AGR and AGS are effective immunomodulatory agents capable of preventing immune system hypofunction. Future research may investigate the exact mechanism to rule out any unforeseen effects of AGR and AGS.

Association between anti-seizure medication and the risk of lower urinary tract infection in patients with epilepsy

PURPOSE

The aim of this retrospective study was to analyze the incidence of lower urinary tract infections (LUTI) and antibiotic prescriptions within 12 months after initial prescription of anti-seizure medication (ASM) between January and December 2020 (index date) and to investigate the association between a broad spectrum of ASMs and the risk of LUTI in patients with epilepsy.

METHODS

This retrospective cohort study included a total of 9186 adult patients (≥18 years) with an initial diagnosis of epilepsy and a prescription of an ASM treated in 1284 general practices in Germany between January 2010 and December 2020 (index date). Six frequently prescribed ASMs with at least 1000 available patients were analyzed. Patients treated with one of six ASMs were matched to each other by propensity scores based on sex, age, and secondary diagnoses. Cox regression models were used to analyze the association between the use of ASM and LUTI risk.

RESULTS

The cumulative LUTI incidence 12 months after the start of therapy was highest in patients treated with pregabalin (16.7%), followed by valproate (11.6%) and gabapentin (10.2%). A similar trend was observed for LUTI with antibiotic prescription (9.2% pregabalin, 6.8% valproate, 6.8% gabapentin). Conditional regression analyses revealed that pregabalin therapy was significantly positively associated with LUTI (HR: 1.76; 95% CI 1.29-2.39) and LUTI-based antibiotic prescription (HR: 2.16; 95% CI 1.43-3.27). Carbamazepine was associated with a significantly lower incidence of LUTI in women (HR: 0.47; 95% CI: 0.30-0.75), but not in men. No significant associations were observed for other ASMs.

CONCLUSION

The present study identifies a significant positive association between ASM and LUTI incidence and antibiotic prescriptions in patients with epilepsy treated with pregabalin, whereas a protective effect was found for carbamazepine in women only. No significant associations were observed for the four remaining ASMs.

Pregabalin mitigates microglial activation and neuronal injury by inhibiting HMGB1 signaling pathway in radiation-induced brain injury

Background

Radiation-induced brain injury (RIBI) is the most serious complication of radiotherapy in patients with head and neck tumors, which seriously affects the quality of life. Currently, there is no effective treatment for patients with RIBI, and identifying new treatment that targets the pathological mechanisms of RIBI is urgently needed.

Methods

Immunofluorescence staining, western blotting, quantitative real-time polymerase chain reaction (Q-PCR), co-culture of primary neurons and microglia, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay, enzyme-linked immunosorbent assay (ELISA), and CRISPR–Cas9-mediated gene editing techniques were employed to investigate the protective effects and underlying mechanisms of pregabalin that ameliorate microglial activation and neuronal injury in the RIBI mouse model.

Results

Our findings showed that pregabalin effectively repressed microglial activation, thereby reducing neuronal damage in the RIBI mouse model. Pregabalin mitigated inflammatory responses by directly inhibiting cytoplasmic translocation of high-mobility group box 1 (HMGB1), a pivotal protein released by irradiated neurons which induced subsequent activation of microglia and inflammatory cytokine expression. Knocking out neuronal HMGB1 or microglial TLR2/TLR4/RAGE by CRISPR/Cas9 technique significantly inhibited radiation-induced NF-κB activation and pro-inflammatory transition of microglia.

Conclusions

Our findings indicate the protective mechanism of pregabalin in mitigating microglial activation and neuronal injury in RIBI. It also provides a therapeutic strategy by targeting HMGB1-TLR2/TLR4/RAGE signaling pathway in the microglia for the treatment of RIBI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02596-7.

Synergistic Antinociceptive Effects of Indomethacin-Pregabalin and Meloxicam-Pregabalin in Paclitaxel-Induced Neuropathic Pain

Neuropathic pain is often closely associated with nerve injury or inflammation, and the role of traditional nonsteroidal anti-inflammatory drugs as adjuvants for treating chemotherapy-induced peripheral neuropathic pain remains unclear. In this study, the potential synergistic antinociceptive effects of indomethacin–pregabalin and meloxicam–pregabalin were evaluated in paclitaxel-induced neuropathic pain and carrageenan-induced inflammatory pain in rodents. Although indomethacin and meloxicam alone only slightly relieved mechanical allodynia in the above two models, isobolographic analysis showed that the combination of indomethacin or meloxicam with pregabalin produced significant synergistic antinociceptive effects for paclitaxel-induced neuropathic pain (IN-PGB, experimental ED₂₅ = [4.41 (3.13–5.82)] mg/kg, theoretical ED₂₅ = [8.50 (6.62–10.32)] mg/kg; MEL-PGB, experimental ED₂₅ = [3.96 (2.62–5.46)] mg/kg, theoretical ED₂₅ = [7.52 (5.73–9.39)] mg/kg). In addition, MEL-PGB dosed via intraplantar injection into the left paw, intragastric injection, or intraperitoneal injection reversed paclitaxel-induced allodynia, indicating that they may act at multiple sites in the neuroaxis and periphery. However, indomethacin–pregabalin and meloxicam–pregabalin exerted antagonistic antiallodynic interactions in carrageenan-induced inflammatory pain in rats. Taken together, coadministration of indomethacin or meloxicam with pregabalin may possess potential therapeutic advantages for treating chemotherapy-induced neuropathic pain.

Old and New Biomarkers for Infection, Inflammation, and Autoimmunity in Treatment-Resistant Affective and Schizophrenic Spectrum Disorders

Affective (AF) and Schizophrenic (SZ) Spectrum disorders manifest with risk factors, involving inflammatory processes linked to infections and autoimmunity. This study searched for novel biomarkers in cerebrospinal fluid (CSF) and peripheral blood. A total of 29 AF and 39 SZ patients with treatment-resistant disease were included. In CSF, the chemokine IL-8 was significantly elevated in AF and SZ patients. IL-8 promotes chemotaxis by neutrophils and may originate from different tissues. S100B, a glia-derived brain damage marker, was higher in CSF from AF than SZ patients. Among the plasma-derived biomarkers, ferritin was elevated in AF and SZ. Soluble CD25, indicating Treg dysfunction, was higher in SZ than in AF patients. Interferon-γ, implying virus-specific immune activation, was positive in selective AF patients, only. Both groups showed elevated expression of immunosuppressive CD33 on monocytes, but higher amounts of CD123+ plasmacytoid dendritic cells were restricted to SZ. In conclusion, chemotactic IL-8 indicates neuronal stress and inflammation in the CSF of both groups. Novel plasma-derived biomarkers such as sCD25 and monocytic CD33 distinguish SZ from AF with an autoimmune phenotype.

Effects of real-ambient PM2.5 exposure plus lipopolysaccharide on multiple organ damage in mice

Background: The toxicological effects of fine particulate matter (PM_2.5) on the cardiopulmonary and nervous systems have been studied widely, whereas the study of PM_2.5 on systemic toxicity is not in-depth enough. Lipopolysaccharide (LPS) can cause multiple organ damage. The combined effects of co-exposure of PM_2.5 plus LPS on the stomach, spleen, intestine, and kidney are still unclear. Purpose: This study was aimed to explore the toxicological effects of co-exposure of PM_2.5 and LPS on the different organs of mice. Research Design and Study Sample Using a real-ambient PM_2.5 exposure system and an intraperitoneal LPS injection mouse model, we investigated multiple organ damage effects on male BALB/c mice after co-exposure of PM_2.5 plus LPS for 23 weeks in Linfen, a city with a high PM_2.5 concentration in China. Data Collection: Eosin-hematoxylin staining, ELISA and the biochemical assay analysed the toxicological effects. Results: The pathological tissue injury on the four organs above appeared in mice co-exposed to PM_2.5 plus LPS, accompanied by the body weight and stomach organ coefficient abnormality, and significant elevation of pro-inflammatory cytokines levels, oxidative stress in the spleen and kidney, and levels of kidney injury molecule (KIM-1) increase in the kidney. There were tissue differences in the pathological damage and toxicological effects on mice after co-exposure, in which the spleen and kidney were more sensitive to pollutants. In the PM_2.5 + LPS group, the superoxide dismutase inhibition and catalase (CAT) activity promotion in the kidney or spleen of mice were significant relative to the PM_2.5 group; the CAT and interleukin-6 (IL-6) levels in the spleen were raised considerably compared with the LPS group. Conclusions: These findings suggested the severity and sensitivity of multiple organ injuries in mice in response to PM_2.5 plus LPS.

Effects of rumen-protected creatine pyruvate on blood biochemical parameters and rumen fluid characteristics in transported beef cattle

Background

The fasting and stress associated with road transportation contributes to a lack of energy and a decline in the immune system of beef cattle. Therefore, it is essential for beef cattle to enhance energy reserves before transportation. Creatine pyruvate (CrPyr) is a new multifunctional nutrient that can provide both pyruvate and creatine, which are two intermediate products of energy metabolism. To investigate the effects of transport and rumen-protected (RP)-CrPyr on the blood biochemical parameters and rumen fluid characteristics of beef cattle, twenty male Simmental crossbred cattle (659 ± 16 kg) aged 18 months were randomly allocated to four groups (n = 5) using a 2 × 2 factorial arrangement with two RP-CrPyr supplemental levels (0 or 140 g/d) and two transport treatments (5 min or 12 h): T_CrPyr140, T_CrPyr0, NT_CrPyr140, and NT_CrPyr0. After feeding for 30 days, three cattle per treatment were slaughtered.

Results

Compared with nontransport, transport decreased the total antioxidant capacity, catalase activity, contents of IgA, interferon γ, interleukin-1β (IL-1β), and IL-6 in serum, and the amounts of total volatile fatty acids (TVFA), acetate, and butyrate in rumen (P < 0.05); increased the serum lipopolysaccharide (LPS) level, contents of rumen LPS and ammonia nitrogen (P < 0.05). RP-CrPyr supplementation decreased the levels of cortisol and LPS in serum and the butyrate concentration in the rumen of beef cattle compared with those in the unsupplemented groups (P < 0.05). RP-CrPyr and transport interaction had a significant effect on the contents of serum tumour necrosis factor-α, IL-6, LPS, ruminal pH, acetate content, and acetate/propionate (P < 0.05). In terms of ruminal bacterial composition, group T_CrPyr0 increased the Prevotella genus abundance compared with group NT_CrPyr0 (P < 0.05), while group T_CrPyr140 increased Firmicutes phylum abundance and decreased Bacteroidetes phylum and genus Prevotella abundance compared with group T_CrPyr0 (P < 0.05). Moreover, Bacteroidetes was positively correlated with serum LPS.

Conclusions

These results indicated that dietary supplementation with RP-CrPyr might be beneficial to alleviate transport stress by decreasing serum cortisol and LPS levels and promoting the restoration of the rumen natural flora.

Anti-inflammatory effect of pregabalin on acetic acid-induced colitis in the rats

Background and purpose:

Inflammatory bowel disease (IBD) is a chronic gastrointestinal disease characterized by the inflammation of the intestine. The available medicinal treatments for IBD are not efficacious enough since they exert various adverse effects. Therefore, the search for new therapeutic agents should be continued. The present study aimed to assess the anti-inflammatory effects of pregabalin on acetic acid-induced colitis in rats.

Experimental approach:

Using 2 mL of 3% acetic acid solution, colitis was intra-rectally induced in rats. Animals were randomly divided into 6 groups including the normal group, colitis control group, pregabalin treatment groups (30, 50, and 100 mg/kg; i.p., respectively), and dexamethasone treatment group (1 mg/kg; i.p.). Macroscopic, microscopic, and biochemical (myeloperoxidase, tumor necrosis factor-alpha, interleukin-6, and interleukin-1 beta) examinations were used to evaluate the efficacy of pregabalin in the inflamed colon.

Findings/Results:

All the applied doses of pregabalin significantly decreased the severity of macroscopic and microscopic colonic damages including ulcer severity, ulcer area, percentage of necrosis, and total colitis index compared to the colitis control group. These results were confirmed by the reduced colonic concentration of tumor necrosis factor-alpha, interleukin-6, interleukin-1 beta, and myeloperoxidase activity.

Conclusion and implications:

Results of this study indicated that pregabalin administration has beneficial effects upon the treatment of experimental colitis, which might be partly due to its anti-inflammatory properties.

Association between chronic pain medications and the severity and mortality of COVID-19: Study protocol for a case-population study

In patients with coronavirus disease 2019 (COVID-19) infection, common drugs may exacerbate symptoms and negatively impact outcomes. However, the role of chronic medications on COVID-19 effects remains poorly understood. We hypothesized that certain chronic pain medications would influence outcomes in patients with COVID-19. The main aim is to assess the effect of these medications on the course of the disease in COVID-19 patients. Secondary aims are to compare disease severity and outcomes in patients with COVID-19 receiving chronic treatment with analgesics or other medications versus untreated patients and to determine prevalence of chronic pain medications in specific subgroups of hospitalized patients for COVID-19. Multicenter case-population study in 15 care centers for patients ≥18 years of age diagnosed and hospitalized with COVID-19. Controls will include patients treated at participating centers for chronic pain during the six-month period prior to March 15th, 2020. Each case will be age- and sex-matched to 10 controls. Patients will be grouped according to disease severity criteria. The primary outcome measures in patients admitted for COVID-19 will be: 1. statistical association between chronic pain medication and disease severity; 2. association between chronic pain treatment and survival. Secondary outcome measures include: 1. prevalence of chronic pain medications in patients with COVID-19 by age and sex; 2. prevalence of chronic pain medications in patients with COVID-19 vs controls. Patients and controls will be paired by age, sex, and geographic residence. Odds ratios with 95% confidence intervals will be calculated to determine the association between each drug and clinical status. Univariate and multivariate analyses will be performed. This is a study protocol. Data is actually being gathered and results are yet not achieved. There is no numerical data presented, so the conclusions cannot be considered solid at this point. Pain medications are likely to influence severity of COVID-19 and patient survival. Identifying those medications that are most closely associated with severe COVID-19 will provide clinicians with valuable data to guide treatment and reduce mortality rates and the long-term sequelae of the disease.

Pilot Analyses of Interferon Subtype Expression Profiles in Patients with Herpes Zoster or Postherpetic Neuralgia

Postherpetic neuralgia (PHN) is a painful neuropathic complication resulting from herpes zoster (HZ). The pain manifests in peripheral nerves infected by herpesviruses, mostly from reactivation of latent varicella zoster virus. Mechanistic descriptions suggest that PHN develops because of disrupted immune system signaling and inflammation or peripheral nerve damage; however, the pathophysiology is not clear. It is difficult to predict/prevent PHN manifestations of HZ patients due to the lack of accurate diagnostics. In this study, sera from healthy controls, HZ patients, and PHN patients were subjected to an interferon (IFN) expression profile (IEP) study. The corresponding cDNAs were analyzed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) using primer pairs against a panel of 21 different IFN subtypes. The results showed that distinct IEPs were observed among HZ and PHN cohorts in comparison to the healthy controls. Together, this pilot study suggested that the IEP study may be used as a molecular tool for diagnosis of PHN and assist in designing new PHN therapeutic protocols.

α-Phellandrene exhibits antinociceptive and tumor-reducing effects in a mouse model of oncologic pain

Medical reports indicate a prevalence of pain in 50% of patients with cancer. In this context, this article investigated the antinociceptive activity of α-PHE using in vivo Sarcoma-180-induced hypernociception in mice to detail its mechanism(s) of antinociception under different conditions of treatment and tumor progression. Firsty, in vitro cytotoxic action was assessed using melanoma B-16/F-10 and S-180 murine cells and colorimetric MTT assays. For in vivo studies, acute treatment with α-PHE (6.25, 12.5, 25 and 50 mg/kg orally by gavage) was performed on the 1st day after S-180 inoculation. Subacute treatments were performed for 8 days starting on the next day (early protocol) or on day 8 after S-180 inoculation (late protocol). For all procedures, mechanical nociceptive evaluations were carried out by von Frey's technique in the subaxillary region peritumoral tissue (direct nociception) and in right legs of S-180-bearing mice (indirect nociception). α-PHE showed in vitro cytotoxic action on B-16/F-10 and S-180 (CI₅₀ values of 436.0 and 217.9 μg/mL), inhibition of in vivo tumor growth (ranging from 47.3 to 82.7%) and decreased direct (peritumoral tissue in subaxillary region) and indirect (right leg) mechanical nociception in Sarcoma 180-bearing mice with early and advanced tumors under acute or subacute conditions of treatment especially at doses of 25 and 50 mg/kg. It improved serum levels of GSH as well as diminished systemic lipid peroxidation, blood cytokines (interleukin-1β, -4, -6, and tumor necrosis factor-α). Such outcomes highlight α-PHE as a promising lead compound that combines antinociceptive and antineoplasic properties. Its structural simplicity make it a cost-effective alternative, justifying further mechanistic investigations and the development of pharmaceutical formulations. Moreover, the protocols developed and standardized here make it possible to use Sarcoma-180 hypernociception model to evaluate the capacity of new antinociceptive molecules under conditions of cancer-related allodynia.

Influence of anti-osteoporosis treatments on the incidence of COVID-19 in patients with non-inflammatory rheumatic conditions

Coronavirus disease 19 (COVID-19) is currently a global pandemic that affects patients with other pathologies. Here, we investigated the influence of treatments for osteoporosis and other non-inflammatory rheumatic conditions, such as osteoarthritis and fibromyalgia, on COVID-19 incidence. To this end, we conducted a cross-sectional study of 2,102 patients being treated at the Rheumatology Service of Hospital del Mar (Barcelona, Spain). In our cohort, COVID-19 cumulative incidence from March 1 to May 3, 2020 was compared to population estimates for the same city. We used Poisson regression models to determine the adjusted relative risk ratios for COVID-19 associated with different treatments and comorbidities. Denosumab, zoledronate and calcium were negatively associated with COVID-19 incidence. Some analgesics, particularly pregabalin and most of the studied antidepressants, were positively associated with COVID-19 incidence, whereas duloxetine presented a negative association. Oral bisphosphonates, vitamin D, thiazide diuretics, anti-hypertensive drugs and chronic non-steroidal anti-inflammatory drugs had no effect on COVID-19 incidence in the studied population. Our results provide novel evidence to support the maintenance of the main anti-osteoporosis treatments in COVID-19 patients, which may be of particular relevance to elderly patients affected by the SARS-CoV-2 pandemic.

Mechanisms Involved in Superiority of Angiotensin Receptor Blockade over ACE Inhibition in Attenuating Neuropathic Pain Induced in Rats

Although previous reports described the beneficial role of angiotensin-converting enzyme inhibitors (ACE-Is) or AT1 receptor blockers (ARBs) in attenuating neuropathic pain (NP), no study has yet explored the exact underlying mechanisms, as well as the superiority of using centrally versus peripherally acting renin-angiotensin-aldosterone system (RAAS) drugs in NP. We investigated the effects of 14 days of treatment with centrally (telmisartan and ramipril) or peripherally (losartan and enalapril) acting ARBs and ACE-Is, respectively, in attenuating peripheral NP induced by sciatic nerve chronic constriction injury (CCI) in rats. We also compared these with the effects of pregabalin, the standard treatment for NP. Behavioral changes, inflammatory markers (NFкB, TNF-α, COX-2, PGE2, and bradykinin), oxidative stress markers (NADPH oxidase and catalase), STAT3 activation, levels of phosphorylated P38-MAPK, ACE, AT1 receptor (AT1R), and AT2 receptor (AT2R), as well as histopathological features, were assessed in the brainstem and sciatic nerve. CCI resulted in clear pain-related behavior along with increased levels of inflammatory and oxidative stress markers, and STAT3 activity, as well as increased levels of phosphorylated P38-MAPK, ACE, AT1R, and AT2R, along with worsened histopathological findings in both the brainstem and sciatic nerve. ARBs improved both animal behavior and all measured parameters in CCI rats and were more effective than ACE-Is. At the tested doses, centrally acting ARBs or ACE-Is were not superior to the peripherally acting drugs of the same category. These findings suggest that ARBs (centrally or peripherally acting) are an effective treatment modality for NP.