Search Results (208)

Pain following orthodontic treatment is the chief complaint of patients undergoing this form of treatment. Although the use of diode lasers has been suggested for pain reduction, the mechanism of laser-induced analgesic effects remains unclear. Neuropeptides, such as substance P (SP) and calcitonin gene-related peptide (CGRP), contribute to the transmission and maintenance of inflammatory pain. Heat shock protein (HSP) 70 plays a protective role against various stresses, including orthodontic forces. This study aimed to examine the effects of diode laser irradiation on neuropeptides and HSP 70 expression in periodontal tissues induced by experimental tooth movement (ETM). For inducing ETM for 24 h, 50 g of orthodontic force was applied using a nickel–titanium closed-coil spring to the upper left first molar and the incisors of 20 male Sprague Dawley rats (7 weeks old). The right side without ETM treatment was considered the untreated control group. In 10 rats, diode laser irradiation was performed on the buccal and palatal sides of the first molar for 90 s with a total energy of 100.8 J/cm². A near-infrared (NIR) laser with a 808 nm wavelength, 7 W peak power, 560 W average power, and 20 ms pulse width was used for the experiment. We measured the number of facial groomings and vacuous chewing movements (VCMs) in the ETM and ETM + laser groups. Immunohistochemical staining of the periodontal tissue with SP, CGRP, and HSP 70 was performed. The number of facial grooming and VCM periods significantly decreased in the ETM + laser group compared to the ETM group. Moreover, the ETM + laser group demonstrated significant suppression of SP, CGRP, and HSP 70 expression. These results suggest that the diode laser demonstrated analgesic effects on ETM-induced pain by inhibiting SP and CGRP expression, and decreased HSP 70 expression shows alleviation of cell damage. Thus, although further validation is warranted for human applications, an NIR diode laser can be used for reducing pain and neuropeptide markers during orthodontic tooth movement. Full article

Current research reported that the number of clinical studies found for botulinum toxin (BoNT) key effects on biochemical biomarkers in head and neck chronic conditions linked to inflammation was very low. There are no systematic reviews of animal studies on this topic, and hence our review aimed to evaluate the quality of the preclinical evidence. We searched PubMed, Scopus, and Web of Science databases, and registries up to 29 January 2024. There were 22 eligible records, and data were available for 11 randomised controlled trials. There were concerns about the risk of bias and great variations of data obtained regarding chronic conditions, which included mostly trigeminal neuralgia. The leading biomarkers were proinflammatory cytokines (IL-1β, TNF-α) and synaptosomal-associated protein-25 (SNAP25), followed by neuron activation marker c-Fos and calcitonin gene-related peptide (CGRP). Overall, data found that BoNT significantly altered the under/over-expression of biomarkers evoked by the investigated disease models and had no effect when the levels of these biomarkers were not changed by the induced chronic conditions in animals. However, there were some mixed results and exceptions, and the certainty evidence found was very low to low. Although the sample sizes detected significant effect size (p < 0.05), most studies are based on male inferior animals, which may limit the recommendations for clinical trials. This study is registered on PROSPERO (CRD42023432411). Full article

Migraine is a neurovascular paroxysmal disorder characterized by neurogenic inflammation and has a remarkable impact on the quality of life. The Food and Drug Administration (FDA) approved onabotulinumtoxin A in 2010 for the prophylactic treatment of chronic migraine. Today, in its 4th decade, it is approved in 100 countries for 15 main indications. Its mechanism of action, based on the inhibition of neurotransmitter release from primary sensory neurons, is very complex: it affords antinociception, but it also has an analgesic effect on neuropathic pain conditions and reduces the need for rescue medications. Genetic variants have been investigated for their potential role in the pathogenesis and clinical expression of migraine and of the response to treatments. These studies primarily involved genes associated with vascular regulation and cardiovascular pathology, including those encoding angiotensin-converting enzyme (ACE) and methylenetetrahydrofolate reductase (MTHFR). However, epigenetics and, particularly, genetic and epigenetic modifications are still poorly studied in terms of understanding the mechanisms implicated in susceptibility to migraine, aura, chronification and response to symptomatic and preventive treatments. In particular, the aim of the present study is to gather evidence on the genetic variants and epigenetic modifications affecting the pathway of the calcitonin gene-related peptide (CGRP), the target of onabotulinumtoxin A and of all the novel monoclonal antibodies. Full article

The presence and function of the opioidergic system in sensory dorsal root ganglia (DRG) was demonstrated in various animal models of pain. To endorse recent functional and transcriptional evidence of opioid receptors in human DRG, this study compared morphological and transcriptional evidence in human and rat DRG using immunofluorescence confocal microscopy and mRNA transcript analysis. Specifically, it examined the neuronal expression of mu (MOR), delta (DOR), and kappa (KOR) opioid receptors, opioid peptide precursors (POMC, PENK, and PDYN), and key pain-signaling molecules. The results demonstrate abundant immunoreactivity in human DRG for key pain transduction receptors, including the thermosensitive ion channels TRPV1, TRPV4 and TRPA1, mechanosensitive PIEZO1 and PIEZO2, and the nociceptive-specific Nav1.8. They colocalized with calcitonin gene-related peptide (CGRP), a marker for peptidergic sensory neurons. Within this same subpopulation, we identified MOR, DOR, and KOR, while their ligand precursors were less abundant. Notably, the mRNA transcripts of MOR and PENK in human DRG were highest among the opioid-related genes; however, they were considerably lower than those of key pain-signaling molecules. These findings were corroborated by functional evidence in demonstrating the fentanyl-induced inhibition of voltage-gated calcium currents in rat DRG, which was antagonized by naloxone. The immunohistochemical and transcriptional demonstration of opioid receptors and their endogenous ligands in both human and rat DRG support recent electrophysiologic and in situ hybridization evidence in human DRG and confirms their potential as analgesic targets. This peripherally targeted approach has the advantage of mitigating central opioid-related side effects, endorsing the potential of future translational pain research from rodent models to humans. Full article

Background: Migraine is associated with structural brain abnormalities, including cortical thickness changes. Anti-calcitonin gene-related peptide monoclonal antibodies (anti-CGRP mAbs) are a novel therapy for migraine prevention, but their effects on cortical structures are poorly understood. Methods: In this prospective age- and sex-matched controlled study, 30 migraine patients receiving either anti-CGRP mAbs (fremanezumab) (n = 15) or oral preventive medications (n = 15) underwent 3T MRI scans before and after treatment. Treatment response was defined as a ≥50% reduction in monthly headache days after 3 months. Cortical thickness was analyzed across 46 cortical regions, comparing patients treated with anti-CGRP mAbs to those receiving oral preventive treatment, as well as responders to non-responders within the anti-CGRP group. Results: Cortical thickness changes did not differ significantly between the anti-CGRP and oral treatment groups. However, among patients receiving anti-CGRP mAbs, responders showed significant decreases in cortical thickness compared to non-responders, particularly in the right caudal anterior cingulate (p = 0.026) and left rostral middle frontal cortex (p = 0.007). These cortical changes correlated with treatment response to anti-CGRP mAbs (β = −0.429, 95% CI [−0.777, −0.081], p = 0.016 in the right caudal anterior cingulate; β = −0.224, 95% CI [−0.390, −0.057], p = 0.008 in the left rostral middle frontal cortex). Conclusions: This exploratory study, based on a small sample size, suggests that cortical thickness changes may be associated with treatment response to anti-CGRP mAbs rather than with CGRP mAb treatment itself. Further studies with larger cohorts are needed to confirm these findings. Full article

Background/Objectives: Pediatric chronic migraine (CM) is a debilitating condition with challenging management due to diagnostic complexities and a lack of evidence-based treatment. Calcitonin gene-related peptide (CGRP)-targeted therapies have transformed adult CM management, but their use in pediatric populations is underexplored. This study evaluated the safety and efficacy of CGRP-targeted therapies combined with structured lifestyle modifications in Korean pediatric patients with CM. Methods: This retrospective study examined 10 pediatric CM patients treated at Gangnam Severance Hospital from 2021 to 2024. Inclusion criteria were as follows: (1) Pediatric Migraine Disability Assessment Scale (PedMIDAS) score ≥ 30, (2) >2 failed preventive therapies, and (3) ≥8 migraine days per month. Patients received CGRP monoclonal antibodies or antagonists, alongside sleep, dietary, and exercise interventions. Changes in migraine burden, neuropsychological outcomes, and adherence to lifestyle interventions were assessed over 12 months. Results: Migraine frequency significantly decreased from a median of 26.5 to 14 days per month (p < 0.001); PedMIDAS scores declined from 58.5 to 48.0 (p = 0.037); and acute analgesic use was reduced from 14 to 5 days per month (p < 0.001). Adherence to lifestyle interventions improved significantly (p < 0.001). No serious adverse events were reported, and minor side effects, such as injection site pain and dizziness, were self-limiting. Conclusions: CGRP-targeted therapies, combined with structured lifestyle modifications, safely and effectively reduce migraine burden in pediatric CM patients. These therapies have facilitated sustainable improvements in management and support their integration into comprehensive pediatric CM care. This study highlights the importance of integrating pharmacologic and lifestyle-based approaches for holistic pediatric migraine management. Full article

Background/Objectives: Complex regional pain syndrome (CRPS) is a primary pain condition that can develop in a limb after a trauma. Although the condition is rare, it may cause lifelong pain and disability. Evidence-based treatments are limited. Neurogenic inflammation induced by the release of neuropeptides, such as calcitonin gene-related peptide (CGRP), is thought to play an important role in the pathophysiology of CRPS. Recently, drugs targeting CGRP have proven to be effective and well tolerated in the treatment of migraine, but their efficacy in other pain conditions, including CRPS, is unclear. The aim of this study is to assess the efficacy of the anti-CGRP antibody fremanezumab on pain in CRPS. Methods: In this randomized, double-blind, placebo-controlled, proof-of-concept study, 60 adult patients with CRPS with a disease duration of 3–36 months are randomized to treatment for eight weeks with fremanezumab 225 mg or placebo administered subcutaneously at a 1:1 rate. The primary objective is to compare the change in pain intensity from baseline to the last week of treatment between fremanezumab and the placebo. Other objectives are to assess pain relief and differences in clinical signs between the groups and to examine if the effect can be predicted by CGRP biomarkers. Adverse events and blinding will also be assessed. Conclusions: If found effective, fremanezumab and other anti-CGRP antibodies may emerge as a mechanism-based treatment option for patients with CRPS, which could hopefully improve the overall care of patients with this devastating disease. Full article

Background/Objectives: Lasmiditan is a newly developed drug for the acute treatment of migraine attacks, but factors associated with its efficacy remain unclear. This study aimed to confirm the efficacy of lasmiditan started at 50 mg under various dosing conditions and identify factors associated with its efficacy. Methods: There are four reasons for prescribing lasmiditan: as an add-on to triptan, if triptan is ineffective, if triptan produces side effects, and when triptan is contraindicated. Lasmiditan was administered at a dose of 50 mg. The efficacy of lasmiditan was defined as the disappearance of headache or a 50% or greater reduction in headache intensity within two hours after dosing. This study included 108 patients with migraines who took lasmiditan. Results: The results for efficacy and the side effects of lasmiditan were as follows: effective without side effects (22), effective with mild side effects (32), ineffective (14), and severe side effects (40). The efficacy rate of lasmiditan 50 mg was 50.0% (54/108). The following factors were found to be associated with lasmiditan’s efficacy: sex, migraine classification, calcium channel blockers, and anti-calcitonin gene-related peptide monoclonal antibody (CGRP-mAb) treatment. The overall incidence of side effects was 66.7%, and the dropout rate was 37.0%. Somnolence was more prevalent in the effective group, and other side effects were more prevalent in patients who dropped out due to the side effects of lasmiditan. Conclusions: Lasmiditan is likely to be effective in males with severe migraine classification and receiving CGRP-mAb treatment. If mild somnolence is a side effect, the drug can be continued and may be effective. Full article

The present study was designed to establish the distribution pattern and immunohistochemical characteristics of phoenixin-immunoreactive (PNX-IR) urinary bladder afferent neurons (UB-ANs) of dorsal root ganglia (DRG) in female pigs. The sensory neurons investigated were visualized with a retrograde tracing method using Fast Blue (FB), while their chemical profile(s) were identified using double-labelling immunohistochemistry with antibodies against PNX, calcitonin gene-related peptide (CGRP), calretinin (CRT), galanin (GAL), neuronal nitric oxide synthase (nNOS), pituitary adenylate cyclase-activating polypeptide (PACAP), somatostatin (SOM) and substance P (SP). Nearly half of UB-ANs contained PNX (45%), and the majority of such encoded sensory neurons were small in size (66%). The most numerous subpopulation of FB/PNX-positive neurons were those containing SP (71%). CGRP, GAL or PACAP were observed in a smaller number of PNX-containing UB-ANs (50%, 30% or 25%, respectively), while PNX-positive sensory neurons simultaneously immunostained with nNOS, CRT or SOM constituted a small fraction of all retrogradely-traced DRG neurons (DRGs; 15%, 6.5% or 1.6%, respectively). Furthermore, the numerical analysis of neurons expressing individual antigens, performed on 10 μm-thick consecutive sections, allows us to state that studied sensory neurons can be classified as neurons “coded” either by the simultaneous presence of SP/CGRP/PACAP/GAL, SP/CGRP/PACAP/NOS, SP/CGRP/PACAP/NOS/CRT and/or SP/CGRP/GAL/PACAP, or, as a separate population, those capable of SOM synthesis (SP/CGRP/SOM/PACAP/GAL-positive neurons). The present study reveals the extensive expression of PNX in the DRGs supplying to the urinary bladder, indicating an important regulatory role of this neuropeptide in the control of physiological function(s) of this organ. Full article

Migraine headache (MH) and cluster headache (CH) are debilitating primary headache disorders that impose a significant global burden. While they share certain clinical features, such as unilateral pain and autonomic dysfunction, their underlying pathophysiological mechanisms remain distinct. Advances in the understanding of neurophysiological features, such as neuroimaging and biomarker research, have provided critical insights into both their overlapping and divergent characteristics. Neurophysiological research has revealed differences in nociceptive processing, cortical excitability, and sensory integration, underscoring the complexity of these conditions. Neuroimaging studies reveal common activation patterns within pain-processing networks, including the trigeminal system and hypothalamus, while highlighting key differences, such as hypothalamic hyperactivity in CH and cortical alterations in MH. Additionally, biomarker research has identified shared elements, including elevated calcitonin gene-related peptide (CGRP), yet distinct variations in its regulation and genetic predispositions. Genome-wide association studies have further elucidated the genetic architecture of these disorders, uncovering susceptibility loci that reinforces their unique yet occasionally intersecting genetic foundations. These multifield advancements not only enhance the understanding of MH and CH pathophysiology but also pave the way for improved diagnostic precision, personalized therapeutic strategies, and future research. Full article

Background: Chronic migraine (CM) is a common complex nervous system disease, often accompanied by symptoms of the digestive tract that interact with each other, leading to prolonged and difficult-to-cure migraines. These symptoms are associated with abnormalities in 5-HT and its receptors. Wuzhuyu decoction (WZYD) is a traditional Chinese medicine prescription commonly used in clinics to treat CM; it relieves gastrointestinal symptoms, such as nausea and vomiting; however, its mechanism is still unclear. Investigating the differences in the role of WZYD compared to existing drugs targeting 5-HT receptors in the treatment of CM not only helps elucidate its pathogenesis but also provides possibilities for the development of new therapeutic approaches. Methods: An inflammation soup (IS)-induced CM male rat model was established. Based on a preliminary experiment, the target of WZYD in treating CM was determined by network pharmacology, and verified by molecular docking. ELISA, immunofluorescence, western blot, and real-time quantitative polymerase chain reaction (RT-qPCR) were used to evaluate the expression levels of CM-related indicators (5-HT, calcitonin gene-related peptide (CGRP), and c-Fos) to ensure the successful establishment of the CM model and the effectiveness of the drug. On this basis, the protein expression levels of 5-HT1A/3A receptors and their cAMP-response element binding protein (CREB) signaling pathway were detected by western blot and immunohistochemistry. The role of 5-HT1A/3A receptors in the treatment of CM by WZYD was validated using a 5-HT1A receptor antagonist (WAY 100635) and a 5-HT3A receptor agonist (SR 57227). Results: The results showed that WZYD increased the expression of 5-HT in the brain, decreased the expression of CGRP, c-Fos, ionized calcium-binding adapter molecule 1 (Iba1), and relieved CM. At the same time, WZYD also increased the expression of the 5-HT1A receptor and decreased the expression of the 5-HT3A receptor in the brain and colon of CM rats. Subsequently, WZYD further exerted its brain-gut integrated therapeutic effects by regulating the CREB signaling pathway mediated by 5-HT1A/3A receptors in the brain and colon of CM rats. Conclusions: WZYD not only regulates neurotransmitters in the brain and colon at the same time, but also specifically regulates 5-HT1A/3A receptors in the brain and colon, which explains the characteristics and advantages of WZYD from a new perspective. While effectively relieving headache symptoms, it also improves related gastrointestinal symptoms, which is more conducive to the treatment of CM. Full article

Elevated levels of homocysteine in the blood plasma (hyperhomocysteinemia, HHCY) positively correlate with migraine symptoms in patients. Experimental studies show a higher sensitivity of rats with prenatal HHCY (pHHCY) to migraine symptoms like allodynia, photophobia, anxiety, and a higher excitability of meningeal trigeminal afferents. In the present study, the roles of purinergic mechanisms in the homocysteine-induced hyperexcitability of the trigeminal ganglion (TG) system using electrophysiological recordings from the trigeminal nerve, Ca²⁺ imaging of cells isolated from TG, and mast cell staining in meninges were investigated. Experiments were performed using rats with pHHCY born from females fed with a high-methionine-containing diet before and during pregnancy. Firstly, we found that lower concentrations of 4-aminopyridine, a K⁺-channel blocker, were able to induce an increase in the nociceptive activity of trigeminal afferents, supporting the hypothesis of the higher excitability of the trigeminal nerve of rats with pHHCY. Trigeminal afferents of rats with pHHCY were more sensitive to the exogenous application of the nonspecific agonist of purinergic ATP receptors. In neurons and satellite glial cells of TG of rats with pHHCY ATP, ADP (an agonist of metabotropic P2Y receptors) and BzATP (an agonist of ionotropic P2X with especially high potency for the P2X7 receptor) induced larger Ca²⁺ transients. The incubation of TG neurons in homocysteine for 24 h increased the ratio of neurons responding simultaneously to ATP and capsaicin. Moreover, rats with pHHCY exhibit a higher rate of degranulation of mast cells and increased response to the agonist of the P2X7 receptor BzATP application. In addition, higher levels of calcitonin gene-related peptide (CGRP) were found in rats with pHHCY. Our results suggest that chronic elevated levels of homocysteine induce the upregulation of ionotropic or metabotropic ATP receptors in neurons, satellite glial cells, and mast cells, which further provide inflammatory conditions and the sensitization of peripheral afferents underlying pain. Full article

Peptidylglycine alpha-amidating monooxygenase (PAM) is the only enzyme known to catalyze C-terminal amidation, a final post-translational modification step essential for the biological activity of over 70 bioactive peptides, including adrenomedullin (ADM), calcitonin gene-related peptide (CGRP), amylin, neuropeptide Y (NPY), and others. Bioactive (amidated) peptide hormones play crucial roles in various physiological processes and have been extensively explored as therapeutic compounds in clinical and preclinical research. However, their therapeutic viability is limited due to their short half-life and, in most cases, the need for prolonged infusion to maintain effective concentrations. PAM itself has also been considered as a therapeutic compound aiming to increase the level of amidated peptide hormones; however, similarly to peptide hormones, PAM’s rapid degradation limits its utility. Here, we present a strategy to enhance PAM stability and bioavailability through PEGylation, significantly extending the enzyme’s half-life in circulation assessed in healthy rats. Furthermore, single subcutaneous (s.c.), intramuscular (i.m.), or intraperitoneal (i.p.) administration of PEGylated PAM resulted in a sustained increase in circulating amidating activity, with peak activity observed at 12–24 h post-bolus administration. Notably, amidating activity remained significantly elevated above baseline levels for up to seven days post-administration, with no observable adverse effects. These findings highlight PEGylated PAM’s potential as a viable therapeutic compound. Full article

The interaction between the neuroendocrine system and the immune system plays a key role in the onset and progression of various diseases. Neuropeptides, recognized as common biochemical mediators of communication between these systems, are receiving increasing attention because of their potential therapeutic applications in immune-related disorders. Additionally, many neuropeptides share significant similarities with antimicrobial peptides (AMPs), and evidence shows that these antimicrobial neuropeptides are directly involved in innate immunity. This review examines 10 antimicrobial neuropeptides, including pituitary adenylate cyclase-activating polypeptide (PACAP), vasoactive intestinal peptide (VIP), α-melanocyte stimulating hormone (α-MSH), ghrelin, adrenomedullin (AM), neuropeptide Y (NPY), urocortin II (UCN II), calcitonin gene-related peptide (CGRP), substance P (SP), and catestatin (CST). Their expression characteristics and the immunomodulatory mechanisms mediated by their specific receptors are summarized, along with potential drugs targeting these receptors. Future studies should focus on further investigating antimicrobial neuropeptides and advancing the development of related drugs in preclinical and/or clinical studies to improve the treatment of immune-related diseases. Full article

Background: Calcitonin gene-related peptide monoclonal antibodies (CGRP mAbs) are a breakthrough migraine treatment, but long-term compliance under limited public insurance coverage has not been well known. This study explores one-year treatment patterns and outcomes of CGRP mAbs using real-world data. Methods: This multicenter retrospective study included migraine patients treated with CGRP monoclonal antibodies (CGRP mAbs) from July 2022 to June 2023. Treatment discontinuation was defined as a gap of over 60 days between injections. Among patients with 12 months of follow-up, adherence was measured using the Proportion of Days Covered (PDC), calculated as the ratio of days covered to the follow-up duration, with PDC ≥ 80% indicating good adherence. Efficacy was also assessed, defined as a ≥50% reduction in monthly headache days and acute medication use. Results: The study included 140 patients (mean age 44.6 ± 12.1 years; 82.9% female). Migraine without aura was predominant (93.6%), and 65.0% had chronic migraine. CGRP mAbs discontinuation occurred in 71.4% of patients, primarily due to headache improvement (22.9%) or lack of efficacy (15.0%). Among 81 patients with 12 months of follow-up, good adherence was observed in 40.7% of patients. Among these patients, 60.6% achieved a ≥50% reduction in monthly headache days, and 51.9% showed a ≥50% reduction in monthly acute medication use. Conclusions: More than two-thirds of patients discontinued the CGRP mAb within 1 year, so these findings emphasize the need for strategies to improve adherence and optimize follow-up plans to enhance patient support. Full article