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The Journal of Pharmacology and... Jun 2024Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of chemotherapy treatment, routinely manifesting as increased pain sensitivity (allodynia) in...
Chronic administration of cannabinoid agonists ACEA (CB1), AM1241 (CB2), and CP55,940 (mixed CB1/CB2) induce sex-specific differences in tolerance and sex hormone changes in a chemotherapy-induced peripheral neuropathy.
Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of chemotherapy treatment, routinely manifesting as increased pain sensitivity (allodynia) in distal extremities. Despite its prevalence, effective treatment options are limited. Cannabinoids are increasingly being evaluated for their ability to treat chronic pain conditions, including CIPN. While previous studies have revealed sex differences in cannabinoid-mediated antinociception in acute and chronic pain models, there is a paucity of studies addressing potential sex differences in the response of CIPN to cannabinoid treatment. Therefore, we evaluated the long-term anti-allodynic efficacy of CB-selective (ACEA), CB-selective (AM1241), and CB/CB mixed (CP55,940) agonists in the cisplatin CIPN model, using both male and female mice. CB selective agonism was observed to have sex differences in the development of tolerance to anti-allodynic effects, with females developing tolerance more rapidly than males, while the anti-allodynic effects of selective CB agonism lacked tolerance development. Compound-specific changes to the female estrous cycle and female plasma estradiol levels were noted, with CB selective agonism decreasing plasma estradiol while CB selective agonism increased plasma estradiol. Chronic administration of a mixed CB/CB agonist resulted in increased mRNA expression of proinflammatory cytokines and endocannabinoid regulatory enzymes in female spinal cord tissue. Ovarian tissue was noted to have proinflammatory cytokine mRNA expression following administration of a CB acting compound while selective CB agonism resulted in decreased proinflammatory cytokines and endocannabinoid regulatory enzymes in testes. These results support the need for further investigation into the role of sex and sex hormones signaling in pain and cannabinoid-mediated antinociceptive effects. CIPN is a common side effect of chemotherapy. We have found that both CB1 and CB2 receptor agonism produce antinociceptive effects in a cisplatin CIPN model. We observed that tolerance to CB1-mediated antinociception developed faster in females and did not develop for CB¬2-mediated antinociception. Additionally, we found contrasting roles for CB1/CB¬2 receptors in the regulation of plasma estradiol in females, with CB1 agonism attenuating estradiol and CB¬2 agonism enhancing estradiol. These findings support the exploration of cannabinoid agonists for CIPN.
PubMed: 38936979
DOI: 10.1124/jpet.124.002165 -
Brazilian Journal of Physical Therapy Jun 2024Migraine may be accompanied by several cervical musculoskeletal dysfunctions, for example an altered performance on the Craniocervical Flexion Test (CCFT). However, CCFT...
BACKGROUND
Migraine may be accompanied by several cervical musculoskeletal dysfunctions, for example an altered performance on the Craniocervical Flexion Test (CCFT). However, CCFT measurement properties are still unclear in patients with migraine.
OBJECTIVES
To determine intra- and inter-examiner reliability, construct validity, standard measurement error (SEM), and minimal detectable change (MDC) of the CCFT in patients with migraine.
METHODS
Women diagnosed with migraine were considered eligible for this study. Participants were assessed by two examiners for the inter-examiner reliability, and with 7-10 days interval for the intra-examiner reliability. Construct validity was assessed considering headache and neck pain frequency and intensity, and self-reported questionnaires, including the Headache Impact Test - 6 items (HIT-6), the 12-item Allodynia Symptom Checklist/Brazil (ASC-12), and the Neck Disability Index (NDI). In addition, participants performed cervical endurance and maximal voluntary isometric contraction of the cervical flexors.
RESULTS
A total of 103 women with migraine were recruited. The intra-examiner reliability was rated as good (ICC= 0.81, 95% CI: 0.73, 0.87), while the inter-examiner reliability was rated as moderate (ICC= 0.55, 95% CI: 0.40, 0.67). The intra and inter-examiner SEM were 1.31 and 1.36 mmHg respectively, and MDC were 3.63 and 3.77 mmHg. The HIT-6 and the cervical endurance flexion test were associated with the CCFT in a multiple linear regression model (p = 0.004, R = 0.35).
CONCLUSION
The CCFT presents adequate intra- and inter-examiner reliability. Better performance on the CCFT test was associated with better HIT-6 scores and greater cervical endurance time, which was not influenced by the presence of neck pain.
PubMed: 38936314
DOI: 10.1016/j.bjpt.2024.101085 -
Naunyn-Schmiedeberg's Archives of... Jun 2024Pain management is a primary goal after oral surgeries, but little is known about sex differences in the sensitivity to analgesics. This study aimed to compare the...
Pain management is a primary goal after oral surgeries, but little is known about sex differences in the sensitivity to analgesics. This study aimed to compare the efficacy of three drugs with analgesic potential on heat and mechanical hyperalgesia, spontaneous pain and locomotion on male and female rats subjected to a model of orofacial postoperative pain. Male and female Wistar rats were submitted to intraoral incision or sham surgery, and on postoperative day 3, the effect of the ibuprofen (30 and 100 mg/kg), acetaminophen (100 and 300 mg/kg) and codeine (3 and 10 mg/kg) was assessed on responses to heat and mechanical facial stimulation, facial grooming, and locomotion. Ibuprofen reduced heat and mechanical hyperalgesia and grooming behavior in male and female rats in a non-sedative dose; acetaminophen dose-dependently reduced the mechanical hyperalgesia and abolished the heat hyperalgesia and the grooming behavior but caused sedation in both sexes; codeine dose-dependently reduced the mechanical hyperalgesia in male and female rats, and reduced the heat hyperalgesia, but females were less sensitive than males. It reduced spontaneous facial grooming in both sexes, but induced hyperlocomotion in females. Ibuprofen presented the most favorable profile, since it reduced over 50% heat and mechanical hyperalgesia in male and female rats, and significantly reduced spontaneous pain, without causing sedation or affecting locomotion. The identification of sex differences in the sensitivity and safety profile of frequently used analgesics can help guide the choice of more effective individualized therapies for pain control.
PubMed: 38935129
DOI: 10.1007/s00210-024-03254-w -
Pharmaceutics Jun 2024Following a mild traumatic brain injury (mTBI), the most prevalent and profoundly debilitating occurrence is the emergence of an acute and persistent post-traumatic...
OBJECTIVE
Following a mild traumatic brain injury (mTBI), the most prevalent and profoundly debilitating occurrence is the emergence of an acute and persistent post-traumatic headache (PTH), for which there are presently no approved treatments. A crucial gap in knowledge exists regarding the consequences of an mTBI, which could serve as a foundation for the development of therapeutic approaches. The activation of trigeminal sensory nerve terminals that innervate the calvarial periosteum (CP)-a densely innervated tissue layer covering the calvarial skull-has been implicated in both migraines and PTHs. We have previously shown that trigeminal oxytocin receptors (OTRs) may provide a therapeutic target for PTHs. This study examined the expression of oxytocin receptors on trigeminal nerves innervating the periosteum and whether these receptors might serve as a therapeutic target for PTHs using a direct application of oxytocin to the periosteum in a rodent model of PTH.
METHODS
We used retrograde tracing and immunohistochemistry to determine if trigeminal ganglion (TG) neurons innervating the periosteum expressed OTRs and/or CGRPs. To model the impact of local inflammation that occurs following an mTBI, we applied chemical inflammatory mediators directly to the CP and assessed for changes in immediate-early gene expression as an indication of neuronal activation. We also determined whether mTBI would lead to expression changes to OTR levels. To determine whether these OTRs could be a viable therapeutic target, we assessed the impact of oxytocin injections into the CP in a mouse model of PTH-induced periorbital allodynia.
RESULTS
The results of these experiments demonstrate the following: (1) the cell bodies of CP afferents reside in the TG and express both OTRs and CGRPs; (2) inflammatory chemical stimulation of the periosteum leads to rapid activation of TG neurons (phospho-ERK (p-ERK) expression), (3) mTBI-induced inflammation increased OTR expression compared to the sham group; and (4) administration of oxytocin into the periosteum on day 2 and day 40 blocked cutaneous allodynia for up to one hour post-administration for both acute and persistence phases in the PTH model-an effect that was preventable by the administration of an OTR antagonist.
CONCLUSION
Taken together, our observations suggest that periosteal trigeminal afferents contribute to post-TBI craniofacial pain, and that periosteum tissue can be used as a potential local target for therapeutics such as oxytocin.
PubMed: 38931882
DOI: 10.3390/pharmaceutics16060760 -
Medicina (Kaunas, Lithuania) Jun 2024: This study aimed to investigate the relationship between neuropathic pain and CREB-binding protein (CBP) and methyl-CpG-binding protein 2 (MeCP2) expression levels in...
: This study aimed to investigate the relationship between neuropathic pain and CREB-binding protein (CBP) and methyl-CpG-binding protein 2 (MeCP2) expression levels in a rat model with spared nerve injury (SNI). : Rat (male Sprague-Dawley white rats) models with surgical SNI (n = 6) were prepared, and naive rats (n = 5) were used as controls. The expression levels of CBP and MeCP2 in the spinal cord and dorsal root ganglion (DRG) were compared through immunohistochemistry at 7 and 14 days after surgery. The relationship between neuropathic pain and CBP/MeCP2 was also analyzed through intrathecal siRNA administration. : SNI induced a significant increase in the number of CBPs in L4 compared with contralateral DRG as well as with naive rats. The number of MeCP2 cells in the dorsal horn on the ipsilateral side decreased significantly compared with the contralateral dorsal horn and the control group. SNI induced a significant decrease in the number of MeCP2 neurons in the L4 ipsilateral DRG compared with the contralateral DRG and naive rats. The intrathecal injection of CBP siRNA significantly inhibited mechanical allodynia induced by SNI compared with non-targeting siRNA treatment. MeCP2 siRNA injection showed no significant effect on mechanical allodynia. : The results suggest that CBP and MeCP2 may play an important role in the generation of neuropathic pain following peripheral nerve injury.
Topics: Animals; Rats, Sprague-Dawley; Methyl-CpG-Binding Protein 2; Neuralgia; Male; Rats; Disease Models, Animal; CREB-Binding Protein; Ganglia, Spinal; RNA, Small Interfering; Peripheral Nerve Injuries; Spinal Cord; Immunohistochemistry
PubMed: 38929606
DOI: 10.3390/medicina60060989 -
Antioxidants (Basel, Switzerland) Jun 2024Chronic migraine is a disabling disorder without effective therapeutic medicine. AMPA receptors have been proven to be essential to pathological pain and headaches, but...
Chronic migraine is a disabling disorder without effective therapeutic medicine. AMPA receptors have been proven to be essential to pathological pain and headaches, but the related regulatory mechanisms in chronic migraine have not yet been explored. In this study, we found that the level of surface GluA2 was reduced in chronic migraine rats. Tat-GluR23Y (a GluA2 endocytosis inhibitor) reduced calcium inward flow and weakened synaptic structures, thus alleviating migraine-like pain sensitization. In addition, the inhibition of GluA2 endocytosis reduced the calcium influx and alleviated mitochondrial calcium overload and ROS generation in primary neurons. Furthermore, our results showed that ROS can induce allodynia and GluA2 endocytosis in rats, thus promoting migraine-like pain sensitization. In our previous study, the dopamine D2 receptor was identified as a potential target in the treatment of chronic migraine, and here we found that dopamine D2 receptor activation suppressed chronic-migraine-related pain sensitization through blocking the GluA2/ROS positive feedback loop in vivo and in vitro. Additionally, ligustrazine, a core component of , was shown to target the dopamine D2 receptor, thereby alleviating ROS production and abnormal nociception in CM rats. This study provides valuable insight into the treatment of chronic migraine.
PubMed: 38929165
DOI: 10.3390/antiox13060725 -
Biomedicines Jun 2024A complication of diabetes is neuropathic pain, which is difficult to control with medication. We have confirmed that neuropathic pain due to mechanical allodynia in...
A complication of diabetes is neuropathic pain, which is difficult to control with medication. We have confirmed that neuropathic pain due to mechanical allodynia in diabetic mice is mediated by a characteristic neuropeptide in the spinal cord. We evaluated the strength of mechanical allodynia in mice using von Frey filaments. When mice were intravenously injected with streptozotocin, mechanical allodynia appeared 3 days later. Antibodies of representative neuropeptides were intrathecally (i.t.) administered to allodynia-induced mice 7 days after the intravenous administration of streptozotocin, and allodynia was reduced by anti-cholecystokinin octapeptide antibodies, anti-nociceptin/orphanin FQ antibodies, and anti-hemokinin-1 antibodies. In contrast, i.t.-administered anti-substance P antibodies, anti-somatostatin antibodies, and anti-angiotensin II antibodies did not affect streptozotocin-induced diabetic allodynia mice. Mechanical allodynia was attenuated by the i.t. administration of CCK-B receptor antagonists and ORL-1 receptor antagonists. The mRNA level of CCK-B receptors in streptozotocin-induced diabetic allodynia mice increased in the spinal cord, but not in the dorsal root ganglion. These results indicate that diabetic allodynia is caused by cholecystokinin octapeptide, nociceptin/orphanin FQ, and hemokinin-1 released from primary afferent neurons in the spinal cord that transmit pain to the brain via the spinal dorsal horn.
PubMed: 38927539
DOI: 10.3390/biomedicines12061332 -
Brain, Behavior, and Immunity Jun 2024Activity-induced muscle pain increases interleukin-1β (IL-1β) release from muscle macrophages and the development of hyperalgesia is prevented by blockade of IL-1β in...
Activity-induced muscle pain increases interleukin-1β (IL-1β) release from muscle macrophages and the development of hyperalgesia is prevented by blockade of IL-1β in muscle. Brain derived neurotrophic factor (BDNF) is released from sensory neurons in response to IL-1β and mediates both inflammatory and neuropathic pain. Thus, we hypothesize that in activity-induced pain, fatigue metabolites combined with IL-1β activate sensory neurons to increase BDNF release, peripherally in muscle and centrally in the spinal dorsal horn, to produce hyperalgesia. We tested the effect of intrathecal or intramuscular injection of BDNF-Tropomyosin receptor kinase B (TrkB) inhibitors, ANA-12 or TrkB-Fc, on development of activity-induced pain. Both inhibitors prevented the hyperalgesia when given before or 24hr after induction of the model in male but not female mice. BDNF messenger ribonucleic acid (mRNA) and protein were significantly increased in dorsal root ganglion (DRG) 24hr after induction of the model in both male and female mice. Blockade of IL-1β in muscle had no effect on the increased BNDF mRNA observed in the activity-induced pain model, while IL-1β applied to cultured DRG significantly induced BDNF expression, suggesting IL-1β is sufficient but not necessary to induce BNDF. Thus, fatigue metabolites, combined with IL-1β, upregulate BDNF in primary DRG neurons in both male and female mice, but contribute to activity-induced pain only in males.
PubMed: 38925417
DOI: 10.1016/j.bbi.2024.06.019 -
British Journal of Pharmacology Jun 2024Mitochondrial dysfunction contributes to the pathogenesis and maintenance of chemotherapy-induced peripheral neuropathy (CIPN), a significant limitation of cancer...
BACKGROUND AND PURPOSE
Mitochondrial dysfunction contributes to the pathogenesis and maintenance of chemotherapy-induced peripheral neuropathy (CIPN), a significant limitation of cancer chemotherapy. Recently, the stimulation of mitophagy, a pivotal process for mitochondrial homeostasis, has emerged as a promising treatment strategy for neurodegenerative diseases, but its therapeutic effect on CIPN has not been explored. Here, we assessed the mitophagy-inducing activity of 3,5-dibromo-2-(2',4'-dibromophenoxy)-phenol (PDE701), a diphenyl ether derivative isolated from the marine sponge Dysidea sp., and investigated its therapeutic effect on a CIPN model.
EXPERIMENTAL APPROACH
Mitophagy activity was determined by a previously established mitophagy assay using mitochondrial Keima (mt-Keima). Mitophagy induction was further verified by western blotting, immunofluorescence, and electron microscopy. Mitochondrial dysfunction was analysed by measuring mitochondrial superoxide levels in SH-SY5Y cells and Drosophila larvae. A thermal nociception assay was used to evaluate the therapeutic effect of PDE701 on the paclitaxel-induced thermal hyperalgesia phenotype in Drosophila larvae.
KEY RESULTS
PDE701 specifically induced mitophagy but was not toxic to mitochondria. PDE701 ameliorated paclitaxel-induced mitochondrial dysfunction in both SH-SY5Y cells and Drosophila larvae. Importantly, PDE701 also significantly ameliorated paclitaxel-induced thermal hyperalgesia in Drosophila larvae. Knockdown of ATG5 or ATG7 abolished the effect of PDE701 on thermal hyperalgesia, suggesting that PDE701 exerts its therapeutic effect through mitophagy induction.
CONCLUSION AND IMPLICATIONS
This study identified PDE701 as a novel mitophagy inducer and a potential therapeutic compound for CIPN. Our results suggest that mitophagy stimulation is a promising strategy for the treatment of CIPN and that marine organisms are a potential source of mitophagy-inducing compounds.
PubMed: 38925168
DOI: 10.1111/bph.16476 -
European Journal of Pain (London,... Jun 2024Migraine is a genetically determined disorder that predisposes to recurrent episodes of headache. Interleukin (IL)-18 is a pro-inflammatory cytokine that seems to play a...
BACKGROUND
Migraine is a genetically determined disorder that predisposes to recurrent episodes of headache. Interleukin (IL)-18 is a pro-inflammatory cytokine that seems to play a role in migraine pathophysiology, and its genetic variants could potentially impact susceptibility to migraine.
OBJECTIVE
To investigate the association between IL18 rs360717 and rs187238 genetic variants with migraine diagnosis and its clinical characteristics.
METHODS
A case-control study was conducted with 152 people with migraine and 155 healthy controls, matched by sex, age, ethnicity, and body mass index. Clinical characteristics of migraine, as well as validated questionnaires regarding disability and impact of migraine, presence of allodynia, anxiety, depression, and hyperacusis were collected. Genotyping for IL18 rs360717 and rs187238 variants was performed using real-time polymerase chain reaction (qPCR) and TaqMan™ method.
RESULTS
The IL18 rs360717A and rs187238G alleles were associated with increased chance of being diagnosed with migraine (OR = 1.53, 95%CI 1.05-2.24, p = 0.028 and OR = 1.46, 95%CI 1.00-2.14, p = 0.049, respectively). In the dominant model, the rs360717GA + AA genotypes were also associated with a higher chance of migraine than the GG genotype (OR = 1.69, 95%CI 1.05-2.73, p = 0.030). In women, in addition to the previous associations, there was also an effect of the variants on the chance of migraine in the codominant models and dominant models. Furthermore, among women, there was an influence on the prevalence of postdrome perception with rs360717GA + AA (OR = 3.04, 95%CI 1.10-8.42, p = 0.032) and rs187238CG + GG (OR = 2.97, 95%CI 1.08-8.21, p = 0.035).
CONCLUSION
IL18 rs360717 and rs187238 variants were associated with migraine diagnosis and postdrome symptoms, especially in women.
SIGNIFICANCE
This study has demonstrated that IL18 rs360717 and rs187238 variants play a role in migraine, influencing the chance of being diagnosed with migraine, particularly among women. There are prospects that IL18 variants could be considered potential genetic biomarkers for migraine.
PubMed: 38922725
DOI: 10.1002/ejp.2302