Pharmacology/Drug Development

Growing evidence points to the histamine system as a promising target for the management of neuropathic pain. Preclinical studies reported the efficacy of HR antagonists in reducing pain hypersensitivity in models of neuropathic pain through an increase of histamine release within the CNS. Recently, a promising efficacy of HR agonists as anti-neuropathic agents has been postulated. Since HR and HR are both localized in neuronal areas devoted to pain processing, the aim of the study is to investigate the role of HR in the mechanism of anti-hyperalgesic action of the HR antagonist GSK189254 in the spared nerve injury (SNI) model in mice. Oral (6 mg/kg), intrathecal (6 µg/mouse), or intra locus coeruleus (LC) (10 µg/µL) administration of GSK189254 reversed mechanical and thermal allodynia in the ipsilateral side of SNI mice. This effect was completely prevented by pretreatment with the HR antagonist JNJ 10191584 (6 µg/mouse i.t.; (10 µg/µL intraLC). Furthermore, GSK189254 was devoid of any anti-hyperalgesic effect in HR deficient mice, compared with wild type mice. Conversely, pretreatment with JNJ 10191584 was not able to prevent the hypophagic activity of GSK189254. In conclusion, we demonstrated the selective contribution of HR to the HR antagonist-induced attenuation of hypernociceptive behavior in SNI mice. These results might help identify innovative therapeutic interventions for neuropathic pain.

Zonulin is a physiologic epithelial and endothelial permeability modulator. Zonulin increases antigen trafficking from the gut lumen into the bloodstream and in between body compartments, a mechanism linked to many chronic inflammatory diseases. Upon its initial discovery, it was noted that zonulin was not a single protein, but rather a family of structurally and functionally related proteins referred to as the zonulin family proteins (ZFPs). ZFPs are members of the mannose associated serine proteases (MASP) family and are the result of high mutation rates leading to many zonulin polymorphisms. Pre-haptoglobin 2, the precursor of haptoglobin 2, was identified as the first eukaryotic member of the ZFPs, and properdin, a key positive regulator of the alternative pathway, as a second member. In this study, we report two additional proteins that are likely ZFPs. Human coagulation factor X (FX) and CD5 antigen-like (CD5L). Both FX and CD5L recombinant proteins were detected by anti-zonulin antibody in Western immunoblot analysis, and both proteins decreased epithelial barrier competency of Caco-2 cell monolayers as established by the Trans Epithelial Electrical Resistance (TEER) assay. These results indicate that FX and CD5L have structural and functional similarities with previously identified ZFPs and, therefore, can be considered new members of this family of proteins.

Neuropathic pain is a pathological pain state with a broad symptom scope that affects patients after nerve injuries, but it can also arise after infections or exposure to toxic substances. Current treatment possibilities are still limited because of the low efficacy and severe adverse effects of available therapeutics, highlighting an emerging need for novel analgesics and for a detailed understanding of the pathophysiological alterations in the onset and maintenance of neuropathic pain. Here, we show that the novel and highly specific FKBP51 inhibitor SAFit2 restores lipid signaling and metabolism in nervous tissue after nerve injury. More specifically, we identify that SAFit2 restores the levels of the C16 dihydroceramide, which significantly reduces the sensitization of the pain-mediating TRPV1 channel and subsequently the secretion of the pro-inflammatory neuropeptide CGRP in primary sensory neurons. Furthermore, we show that the C16 dihydroceramide is capable of reducing acute thermal hypersensitivity in a capsaicin mouse model. In conclusion, we report for the first time the C16 dihydroceramide as a novel and crucial lipid mediator in the context of neuropathic pain as it has analgesic properties, contributing to the pain-relieving properties of SAFit2.

This study observed the cutaneous analgesic effect of adrenergic agonists when combined with lidocaine. We aimed at the usefulness of 4 adrenergic agonists and epinephrine as analgesics or as tools to prolong the effect of local anesthetics using a model of cutaneous trunci muscle reflex (pinprick pain) in rats. We showed that subcutaneous 4 adrenergic agonists and epinephrine, as well as the local anesthetic bupivacaine and lidocaine, developed a concentration-dependent cutaneous analgesia. The rank order of the efficacy of different compounds (ED ; median effective dose) was epinephrine [0.013 (0.012 – 0.014) μmol] > oxymetazoline [0.25 (0.22 – 0.28) μmol] > naphazoline [0.42 (0.34 – 0.53) μmol] = bupivacaine [0.43 (0.37 – 0.50) μmol] > xylometazoline [1.34 (1.25 – 1.45) μmol] > lidocaine [5.86 (5.11 – 6.72) μmol] > tetrahydrozoline [6.76 (6.21 – 7.36) μmol]. The duration of full recovery caused by tetrahydrozoline, oxymetazoline, or xylometazoline was greater (P<0.01) than that induced via epinephrine, bupivacaine, lidocaine, or naphazoline at equianesthetic doses (ED , ED , and ED ). Co-administration of lidocaine (ED ) with 4 adrenergic agonists or epinephrine enhanced the cutaneous analgesic effect. We observed that 4 adrenergic agonists and epinephrine induce analgesia by themselves, and such an effect has a longer duration than local anesthetics. Co-administration of lidocaine with the adrenergic agonist enhances the analgesic effect, and the cutaneous analgesic effect of lidocaine plus naphazoline (or oxymetazoline) is greater than that of lidocaine plus epinephrine.

A novel peptide AnmTX Sco 9a-1 with the β-hairpin fold was isolated from the swimming sea anemone (Actinostolidae family). The peptide consists of 28 amino acid residues, including modified hydroxyproline residue, and its measured molecular mass is 2960 Da. The peptide was not toxic on mice; however, it stimulated their exploratory motivation and active search behavior, and demonstrated an anti-anxiety effect. AnmTX Sco 9a-1 at doses of 0.1 and 1 mg/kg reduced the volume of edema during 24 h better than the nonsteroidal anti-inflammatory drug, Diclofenac, at dose of 1 mg/kg in a model of acute local λ-carrageenan-induced inflammation. ELISA analysis of the animal's blood showed that peptide at a dose of 1 mg/kg reduced the content of tumor necrosis factor-α (TNF-α), a pro-inflammatory mediator responsible in the edema development, up to the level of TNF-α in the intact group. Besides, AnmTX Sco 9a-1 demonstrated a significant analgesic effect on acute pain sensitivity in the carrageenan-induced thermal hyperalgesia model at doses of 0.1 and 1 mg/kg. Activity of AnmTX Sco 9a-1 was shown not to be associated with modulation of nociceptive ASIC channels.

Pitavastatin is a competitive HMG-CoA reductase inhibitor for lowering of cholesterol level and low density lipoprotein cholesterol. This study was designed to evaluate the effect of pitavastatin in neuropathic pain induced by partial sciatic nerve ligation along with neuronal changes in Wister rats.

Transient receptor potential vanillic acid 1 (TRPV1) is an ion channel activated by heat and inflammatory factors involved in the development of various types of pain. The P2X7 receptor is in the P2X family and is associated with pain mediated by satellite glial cells. There might be some connection between the P2X7 receptor and TRPV1 in neuropathic pain in diabetic rats. A type 2 diabetic neuropathic pain rat model was induced using high glucose and high-fat diet for 4 weeks and low-dose streptozocin (35 mg/kg) intraperitoneal injection to destroy islet B cells. Male Sprague Dawley rats were administrated by intrathecal injection of P2X7 shRNA and p38 inhibitor, and we recorded abnormal mechanical and thermal pain and nociceptive hyperalgesia. One week later, the dorsal root ganglia from the L4-L6 segment of the spinal cord were harvested for subsequent experiments. We measured pro-inflammatory cytokines, examined the relationship between TRPV1 on neurons and P2X7 receptor on satellite glial cells by measuring protein and transcription levels of P2X7 receptor and TRPV1, and measured protein expression in the PKCε/P38 MAPK/NF-κB signaling pathway after intrathecal injection. P2X7 shRNA and p38 inhibitor relieved hyperalgesia in diabetic neuropathic pain rats and modulated inflammatory factors in vivo. P2X7 shRNA and P38 inhibitors significantly reduced TRPV1 expression by downregulating the PKCε/P38 MAPK/NF-κB signaling pathway and inflammatory factors in dorsal root ganglia. Intrathecal injection of P2X7 shRNA alleviates nociceptive reactions in rats with diabetic neuropathic pain involving TRPV1 via PKCε/P38 MAPK/NF-κB signaling pathway.

Morphine and other opioids are used to manage cancer-related pain; however, the role of these drugs in cancer progression remains controversial. Emerging evidence indicates that morphine can activate Toll-like receptor 4 (TLR4) and its signaling pathways, by the way the activation and expression of TLR4 can promote melanoma. In this study, we investigated the effects of morphine on the expression of TLR4 and promotion of melanoma in mice.

Recent data indicated a high incidence of inappropriate management of neuromuscular block, with a high rate of residual paralysis and relaxant-associated postoperative complications. These data are alarming in that the available neuromuscular monitoring, as well as myorelaxants and their antagonists basically allow well tolerated management of neuromuscular blockade. In this first European Society of Anaesthesiology and Intensive Care (ESAIC) guideline on peri-operative management of neuromuscular block, we aim to present aggregated and evidence-based recommendations to assist clinicians provide best medical care and ensure patient safety. We identified three main clinical questions: Are myorelaxants necessary to facilitate tracheal intubation in adults? Does the intensity of neuromuscular blockade influence a patient's outcome in abdominal surgery? What are the strategies for the diagnosis and treatment of residual paralysis? On the basis of this, PICO (patient, intervention, comparator, outcome) questions were derived that guided a structured literature search. A stepwise approach was used to reduce the number of trials of the initial research (n = 24 000) to the finally relevant clinical studies (n = 88). GRADE methodology (Grading of Recommendations, Assessment, Development and Evaluation) was used for formulating the recommendations based on the findings of the included studies in conjunction with their methodological quality. A two-step Delphi process was used to determine the agreement of the panel members with the recommendations: R1 We recommend using a muscle relaxant to facilitate tracheal intubation (1A). R2 We recommend the use of muscle relaxants to reduce pharyngeal and/or laryngeal injury following endotracheal intubation (1C). R3 We recommend the use of a fast-acting muscle relaxant for rapid sequence induction intubation (RSII) such as succinylcholine 1 mg kg-1 or rocuronium 0.9 to 1.2 mg kg-1 (1B). R4 We recommend deepening neuromuscular blockade if surgical conditions need to be improved (1B). R5 There is insufficient evidence to recommend deep neuromuscular blockade in general to reduce postoperative pain or decrease the incidence of peri-operative complications. (2C). R6 We recommend the use of ulnar nerve stimulation and quantitative neuromuscular monitoring at the adductor pollicis muscle to exclude residual paralysis (1B). R7 We recommend using sugammadex to antagonise deep, moderate and shallow neuromuscular blockade induced by aminosteroidal agents (rocuronium, vecuronium) (1A). R8 We recommend advanced spontaneous recovery (i.e. TOF ratio >0.2) before starting neostigmine-based reversal and to continue quantitative monitoring of neuromuscular blockade until a TOF ratio of more than 0.9 has been attained. (1C).