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Postcraniotomy pain protocols use opioids, which are considered suboptimal analgesia following this procedure. Multimodal analgesia components are sparse. Our null hypothesis states that sumatriptan is not different to placebo in addition to usual intravenous opioids, for the treatment of acute postcraniotomy pain.
Learn More >Critical for diverse biological processes, proteases represent one of the largest families of pharmaceutical targets. To inhibit pathogenic proteases with desired selectivity, monoclonal antibodies (mAbs) hold great promise as research tools and therapeutic agents. However, identification of mAbs with inhibitory functions is challenging because current antibody discovery methods rely on binding rather than inhibition. This study developed a highly efficient selection method for protease inhibitory mAbs by coexpressing 3 recombinant proteins in the periplasmic space of -an antibody clone, a protease of interest, and a β-lactamase modified by insertion of a protease cleavable peptide sequence. During functional selection, inhibitory antibodies prevent the protease from cleaving the modified β-lactamase, thereby allowing the cell to survive in the presence of ampicillin. Using this method to select from synthetic human antibody libraries, we isolated panels of mAbs inhibiting 5 targets of 4 main protease classes: matrix metalloproteinases (MMP-14, a predominant target in metastasis; MMP-9, in neuropathic pain), β-secretase 1 (BACE-1, an aspartic protease in Alzheimer's disease), cathepsin B (a cysteine protease in cancer), and Alp2 (a serine protease in aspergillosis). Notably, 37 of 41 identified binders were inhibitory. Isolated mAb inhibitors exhibited nanomolar potency, exclusive selectivity, excellent proteolytic stability, and desired biological functions. Particularly, anti-Alp2 Fab A4A1 had a binding affinity of 11 nM and inhibition potency of 14 nM, anti-BACE1 IgG B2B2 reduced amyloid beta (Aβ) production by 80% in cellular assays, and IgG L13 inhibited MMP-9 but not MMP-2/-12/-14 and significantly relieved neuropathic pain development in mice.
Learn More >Chemotherapy-induced peripheral neuropathy (CIPN) is a common dose-limiting side effect of several anti-neoplastics and a main cause of sensory disturbances in cancer survivors, negatively impacting patients' quality of life. Peripheral nerve degeneration or small fibre neuropathy is generally accepted as the underlying mechanism in the development of CIPN. Recent evidence has contributed to clarify the determinant role of cytokines and chemokines in the process leading to neuronal hyperexcitability. Exposure to oxaliplatin triggers alterations in peripheral neuropathic pathways previously linked to IL-8 pathway. We investigated a novel selective inhibitor of IL-8 receptors, DF2726A, and showed its effects in counteracting CINP pathways, extending the relevance of the activation of IL-8 pathway to the class of platinum chemotherapeutics. Based on our results, we suggest that DF2726A might be a promising candidate for clinical treatment of CIPN conditions due to its efficacy and optimized pharmacokinetic/pharmacodynamic profile.
Learn More >We studied the efficacy and safety of a second dose of lasmiditan for acute treatment of migraine.
Learn More >Cannabinoid 1 (CBR) and delta opioid receptors (DOR) associate to form heteromers that exhibit distinct pharmacological properties. Not much is known about CBR-DOR heteromer location or signaling along the pain circuit in either animal models or patients with chemotherapy-induced peripheral neuropathy (CIPN). Here, we use paclitaxel to induce CIPN in mice and confirm the development of mechanical allodynia. Under these conditions, we find significant increases in CBR-DOR heteromers in the dorsal spinal cord of mice with CIPN as well as in postmortem spinal cords from human subjects with CIPN compared to controls. Next, we investigated receptor signaling in spinal cords of mice with CIPN and found that treatment with a combination of low signaling doses of CBR and DOR ligands leads to significant enhancement in G-protein activity that could be selectively blocked by the CBR-DOR antibody. Consistent with this, administration of subthreshold doses of a combination of ligands (CBR agonist, Hu-210, and DOR agonist, SNC80) leads to significant attenuation of allodynia in mice with CIPN that is not seen with the administration of individual ligands, and this could be blocked by the CBR-DOR antibody. Together, these results imply that CBR-DOR heteromers upregulated during CIPN-associated mechanical allodynia could serve as a potential target for treatment of neuropathic pain including CIPN.
Learn More >The CDC Guideline for Prescribing Opioids for Chronic Pain recommends considering prescribing naloxone when factors that increase risk for overdose are present (e.g., history of overdose or substance use disorder, opioid dosages ≥50 morphine milligram equivalents per day [high-dose], and concurrent use of benzodiazepines). In light of the high numbers of drug overdose deaths involving opioids, 36% of which in 2017 involved prescription opioids, improving access to naloxone is a public health priority. CDC examined trends and characteristics of naloxone dispensing from retail pharmacies at the national and county levels in the United States.
Learn More >Deaths associated to tramadol, a synthetic opioid, are rising globally. Herein, we characterize prescription patterns of tramadol relative to other opioids in the USA from 2012 to 2015, by geographic region and physician specialty.
Learn More >Painful diabetic neuropathy (PDN) is a serious symptom that compromises quality of life and remains without effective pharmacological treatment. The transient receptor vanilloid 4 (TRPV4) is a cation-permeable channel implicated in sensory transduction and pain signalling. Therefore, drugs that act on TRPV4 may have therapeutic applications to treat PDN. In the present work, we assessed the effect of the selective TRPV4 channel antagonist HC-067047 on painful neuropathy associated with streptozotocin (STZ)-induced diabetes in mice. STZ-treated animals presented both mechanical and cold allodynia at 6 weeks after diabetes induction. Notably, HC-067047 (1 mg/kg, s.c.) given daily between 2 and 6 weeks after diabetes induction significantly prevented the development of mechanical allodynia. Additionally, both single and repeated treatments with HC-067047 (10 mg/kg, s.c.) significantly reverted established mechanical allodynia induced by STZ. However, HC-067047 was not capable of affecting either thermal cold allodynia or hyperglycemia. Similarly, HC-067047 treatments showed no effect on body weight, temperature, locomotor activity or motor coordination of control mice. Immunohistochemistry assay showed that TRPV4 expression was not different in sciatic nerve, dorsal root ganglia (DRG) or hind paw plantar skin from diabetic and non-diabetic mice, suggesting that HC-067047 acts on constitutive receptors to inhibit mechanical allodynia. Taken together, the data generated in the present study show the potential relevance of using TRPV4 antagonists to treat painful neuropathy associated with diabetes.
Learn More >The gasotransmitter hydrogen sulfide (HS) is known to regulate many pathophysiological processes. Preclinical assays have demonstrated that HS donors exhibit anti-inflammatory and antinociceptive activities, characterized by reduction of inflammatory mediators production, leukocytes recruitment, edema and mechanical allodynia. In the present study, the effects induced by 4-methylbenzenecarbothioamide (4-MBC) in models of pain and inflammation in mice, the mechanisms mediating such effects and the HS-releasing property of this compound were evaluated. 4-MBC spontaneously released HS in vitro in the absence of organic thiols. Intraperitoneal (i.p.) administration of 4-MBC (100 or 150 mg/kg) reduced the second phase of the nociceptive response induced by formaldehyde and induced a long lasting inhibitory effect on carrageenan mechanical allodynia. 4-MBC antiallodynic effect was not affected by previous administration of naltrexone or glibenclamide. 4-MBC (50, 100 or 150 mg/kg, i.p.) induced a long lasting inhibitory effect on paw edema induced by carrageenan. The highest dose (150 mg/kg, i.p.) of 4-MBC inhibited tumor necrosis factor-α and CXCL1 production and myeloperoxidase activity induced by carrageenan. Mechanical allodynia and paw edema induced by carrageenan were not inhibited by the 4-MBC oxo analogue (p-toluamide). In summary, 4-MBC, an HS releasing thiobenzamide, exhibits antinociceptive and anti-inflammatory activities. These activities may be due to reduced cytokine and chemokine production and neutrophil recruitment. The HS releasing property is likely essential for 4-MBC activity. Our results indicate that 4-MBC may represent a useful pharmacological tool to investigate the biological roles of HS.
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