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Over the last two decades, affirmative diagnoses of osteoarthritis in the United States have tripled due to increasing rates of obesity and an aging population. Hemp-derived cannabidiol (CBD) is the major non-THC component of cannabis and has been promoted as a potential treatment for a wide variety of disparate inflammatory conditions. Here we evaluated CBD for its ability to modulate the production of pro-inflammatory cytokines in vitro and in murine models of induced inflammation and further validated the ability of a liposomal formulation to increase bioavailability in mice and in humans. Subsequently, the therapeutic potential of both naked and liposomally-encapsulated CBD was explored in a 4-week, randomized placebo-controlled, double-blinded study in a spontaneous canine model of osteoarthritis. In vitro and in mouse models, CBD significantly attenuated the production of pro-inflammatory cytokines IL-6 and TNF-α while elevating levels of anti-inflammatory IL-10. In the veterinary study, CBD significantly decreased pain and increased mobility in a dose-dependent fashion among animals with an affirmative diagnosis of osteoarthritis. Liposomal CBD (20 mg/day) was as effective as the highest dose of non-liposomal CBD (50 mg/day) in improving clinical outcomes. Hematocrit, comprehensive metabolic profile, and clinical chemistry indicated no significant detrimental impact of CBD administration over the four-week analysis period. This study supports the safety and therapeutic potential of hemp-derived CBD for relieving arthritic pain and suggests follow-up investigations in humans is warranted.
Learn More >The objective was to perform a systematic review and meta-analysis of the literature on the effects of buprenorphine on chronic pain outcomes (i.e., patient-reported pain intensity) in patients with and without opioid use disorder (OUD).
Learn More >The analgesic potency of morphine-6-glucuronide (M6G) has been shown to be 50-fold higher than morphine after intracerebral injection. However, the brain penetration of M6G is significantly lower than morphine, thus limiting its usefulness in pain management. Here, we created new entities by the conjugation of the Angiopep-2 peptide (An2) that crosses the blood-brain-barrier (BBB) by LRP1 receptor-mediated transcytosis, with either morphine or M6G. We demonstrated improvement of BBB permeability of these new entities compared with that of unconjugated M6G and morphine. Intravenous or subcutaneous administration of the An2-M6G conjugate exerted greater and more sustained analgesic activity than equivalent doses of either morphine or M6G. Likewise, subcutaneous An2-morphine induced a delayed but prolonged antinociceptive effect. The effects of these conjugates on the gastrointestinal tract motility were also evaluated. An2-morphine significantly reduced the intestinal transit time while An2-M6G exhibited a reduced constipation profile, as compared to morphine. In summary, we have developed new brain-penetrant opioid conjugates exhibiting improved analgesia to side-effect ratios. These results thus support the use of An2 carrier peptides as an innovative BBB targeting technology to deliver effective drugs such as M6G for the pain management. SIGNIFICANCE STATEMENT: The metabolite M6G does not cross efficiently the blood-brain barrier. The LRP1 peptide ligand Angiopep-2 may serve as an effective drug delivery system to the brain. Here, we demonstrated that the coupling of M6G to An2 improves its brain penetration and significantly increases its analgesic potency. The An2-M6G conjugate has a favorable side-effect profile that includes reduction of developing constipation. An2-M6G exhibits a unique pharmacodynamic profile with a better therapeutic window than morphine.
Learn More >Muscarinic antagonists promote sensory neurite outgrowth in vitro and prevent and/or reverse multiple indices of peripheral neuropathy in rodent models of diabetes, chemotherapy-induced peripheral neuropathy and HIV protein-induced neuropathy when delivered systemically. We measured plasma concentrations of the M1 receptor selective muscarinic antagonist pirenzepine when delivered by sub-cutaneous injection, oral gavage or topical application to the skin and investigated efficacy of topically delivered pirenzepine against indices of peripheral neuropathy in diabetic mice. Topical application of 2% pirenzepine to the paw resulted in plasma concentrations 6hr post-delivery that approximated those previously shown to promote neurite outgrowth in vitro. Topical delivery of pirenzepine to the paw of streptozotocin-diabetic mice dose-dependently (0.1-10.0%) prevented tactile allodynia, thermal hypoalgesia and loss of epidermal nerve fibers in the treated paw and attenuated large fiber motor nerve conduction slowing in the ipsilateral limb. Efficacy against some indices of neuropathy was also noted in the contralateral limb, indicating systemic effects following local treatment. Topical pirenzepine also reversed established paw heat hypoalgesia while withdrawal of treatment resulted in a gradual decline in efficacy over 2-4 weeks. Efficacy of topical pirenzepine was muted when treatment was reduced from 5 to 3 or 1 days per week. Similar local effects were noted with the non-selective muscarinic receptor antagonist atropine when applied either to the paw or to the eye. Topical delivery of muscarinic antagonists may serve as a practical therapeutic approach to treating diabetic and other peripheral neuropathies. SIGNIFICANCE STATEMENT: Muscarinic antagonist pirenzepine alleviates diabetic peripheral neuropathy when applied topically in mice.
Learn More >The long-term treatment of chronic pain by opioids is limited by tolerance and risk of addiction/dependence. Previously, we have shown that combination treatment of morphine with a dopamine D or D receptor modulator restored morphine analgesia in morphine-resistant neuropathic pain and decreased morphine's reward potential in an acute setting. Here, we investigated whether such adjunct therapy with a dopamine D receptor preferring antagonist (SCH 39166) or a dopamine D receptor preferring agonist (pramipexole) could prevent morphine tolerance and reduce withdrawal symptoms. Initially, tolerance to the combination of morphine + pramipexole was assessed in mice. Mice receiving intraperitoneal injections of morphine showed reduced thermal thresholds on Day 7 whereas those receiving morphine + pramipexole maintained analgesia at Day 7. Next, tolerance and withdrawal to both combinations were tested over 14 days in rats. Rats were assigned one of four drug conditions, (1) saline, 2) morphine, 3) morphine + SCH 39166, 4) morphine + pramipexole), for chronic administration via osmotic pumps. Chronic administration of morphine over 14 days resulted in a significant reduction of morphine analgesia. However, analgesia was maintained when morphine was administered with either the dopamine D receptor preferring antagonist or the D receptor preferring agonist. Withdrawal symptoms peaked at 48 h and were decreased in rats receiving either combination compared to morphine alone. The data suggests that adjunct therapy with dopamine D or D receptor preferring modulators prevents morphine tolerance and reduces the duration of morphine withdrawal symptoms, and thus this combination has potential for long-term pain management therapy.
Learn More >The gabapentinoid drugs gabapentin and pregabalin (Neurontin® and Lyrica®) are mainstay treatments for neuropathic pain and for preventing focal seizures. Both drugs have similar effects to each other in animal models and clinically. Studies have shown that a protein first identified as an auxiliary subunit of voltage-gated calcium channels (the alpha2-delta subunit, α2δ-1 or Cava2d1) is the high-affinity binding site for gabapentin and pregabalin, and is required for the efficacy of these drugs. The α2δ-1 protein is required for the ability of gabapentin and pregabalin to reduce neurotransmitter release in neuronal tissue, consistent with a therapeutic mechanism of action via voltage-gated calcium channels. However, recent studies have revealed that α2δ-1 interacts with several proteins in addition to voltage-gated calcium channels, and these additional proteins could be involved in gabapentinoid pharmacology. Furthermore, gabapentin and pregabalin have been shown to modify the action of a subset of NMDA-sensitive glutamate receptors, neurexin-1, and thrombospondin proteins by binding to α2δ-1. Thus, these effects may contribute substantially to gabapentinoid therapeutic mechanism of action. SIGNIFICANCE STATEMENT: It is widely believed that gabapentin and pregabalin act by modestly reducing the membrane localization and activation of voltage-gated calcium channels at synaptic endings in spinal cord and neocortex via binding to the α2δ-1 protein. However, recent findings show that the α2δ-1 protein also interacts with NMDA-sensitive glutamate receptors, neurexin-1α, thrombospondins (adhesion molecules), and other presynaptic proteins. These newly discovered interactions, in addition to actions at calcium channels, may be important mediators of gabapentin and pregabalin therapeutic effects.
Learn More >Migraine is a debilitating neurologic disease. People who experience migraine can have substantial disability, impaired functioning and a decreased quality of life (QoL). Expert recommendations suggest that people with frequent migraine attacks or severe impairment related to attacks may benefit from preventive treatment. Despite these recommendations and the existence of evidence-based guidelines for the use of preventive medication, many people who are candidates for preventive therapies do not receive them. Thus, there is still a substantial unmet need for preventive migraine treatment. Calcitonin gene-related peptide (CGRP) has a demonstrated role in the pathophysiology of migraine. Galcanezumab-gnlm (galcanezumab) is a humanized monoclonal antibody that binds to the CGRP ligand and prevents binding to its receptor. It is administered as a once-monthly subcutaneous injection. The aim of this review is to present a comprehensive overview of the existing short- and long-term efficacy and safety data for galcanezumab in patients with migraine. Data from the phase 3, randomized, double-blind, placebo-controlled EVOLVE-1, EVOLVE-2 and REGAIN studies show that galcanezumab treatment for 3 or 6 months results in overall reduction in mean monthly migraine headache days in patients with episodic (EVOLVE-1 and EVOLVE-2) and chronic (REGAIN) migraine. Greater proportions of patients with episodic migraine receiving galcanezumab versus placebo demonstrated a ≥ 50%, ≥ 75% and 100% response to therapy and reported a lower level of disability and an improvement in functioning and QoL. Similarly, when compared with placebo, greater proportions of patients with chronic migraine treated with galcanezumab demonstrated a ≥ 50% and ≥ 75% response and reported improved functioning. A 12-month open-label study demonstrated the continued efficacy of galcanezumab for up to 12 months. In all studies galcanezumab was well tolerated. In conclusion, data from pivotal studies show that galcanezumab may fulfill an unmet need in the treatment of patients with migraine who require preventive therapy.
Learn More >Oxaliplatin is a platinum-based antineoplastic drug commonly used for treating colorectal, gastric, and pancreatic cancer. However, it frequently causes peripheral neuropathy as dose-limiting toxicity and is lacking a strategy for prevention. Alogliptin, a dipeptidyl peptidase 4 (DPP-4) inhibitor, is an oral antidiabetic drug. Previous studies have shown that DPP-4 inhibitors have pleiotropic effects, including neuroprotection. In this study, we investigated the effects of alogliptin on oxaliplatin-induced peripheral neuropathy using in vitro and in vivo models. In PC12 cells, alogliptin attenuated neurite disorders induced by oxaliplatin and cisplatin. The repeated injection of oxaliplatin caused mechanical allodynia and axonal degeneration of the sciatic nerve in rats. These neuropathies were ameliorated by co-administration of alogliptin. Moreover, alogliptin did not attenuate tumor cytotoxicity of oxaliplatin in the cultured colon, gastric, or pancreatic cancer cell lines and tumor-bearing mice. These findings suggest that alogliptin may be beneficial for preventing oxaliplatin-induced peripheral neuropathy.
Learn More >Omiganan is an indolicidin analogue with antimicrobial properties that could be beneficial for patients with atopic dermatitis. This randomized, double-blind, placebo-controlled phase II trial explored efficacy, pharmacodynamics and safety of topical omiganan once daily in 36 patients with mild to moderate AD. Patients were randomized to apply topical omiganan 1%, omiganan 2.5% or vehicle gel to one target lesion once daily for 28 consecutive days. Small but significant improvements of the local oSCORAD index and morning itch were observed in the omiganan 2.5% group compared to the vehicle gel group (-18.5%; 95%CI=-32.9,-1.0; p=0.04 and -8.2; 95%CI=-16.3,-0.2; p=0.05 respectively). A shift from lesional to non-lesional skin microbiota was observed in both omiganan treatment groups, in contrast to the vehicle group. In conclusion, treatment with topical omiganan improved dysbiosis in patients with mild to moderate atopic dermatitis and small but statistically significant improvement of clinical scores were detected. Our findings warrant further exploration in future clinical trials.
Learn More >Therapies to treat chronic neuropathic pain and its associated comorbidities are limited. Recent studies demonstrated that the administration of slow-releasing hydrogen sulfide (HS) donors inhibited chemotherapy-induced neuropathic pain. However, the antidepressant or anxiolytic effects of these compounds and their mechanisms of action during chronic neuropathic pain have not been evaluated.
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