Botulinum Toxin in the Treatment of Headache

Poor Adherence to the Mediterranean Diet and Sleep Disturbances Are Associated with Migraine Chronification and Disability among an Adult Population in the Lazio Region, Italy

Lifestyle factors, such as diet and sleep quality, are receiving increasing interest as accessible therapeutic approaches to migraine. The Mediterranean diet (MD) has shown clear benefits in cardiovascular and metabolic diseases, as well as in sleep patterns. Here, our objective was to identify the impact of adherence to the MD and other lifestyle factors on the clinical burden of migraine. For this purpose, we enrolled 170 migraine patients and 100 controls, assessing the clinical disability of headache using standardized clinical scales (HIT-6 and MIDAS) in the migraineur cohort and lifestyle patterns in both groups through the PREDIMED score for MD adherence, the IPAQ scale for physical activity, and BMI. Subjects were also screened for sleep-wake disturbances based on the Pittsburgh Sleep Quality Index (PSQI). We found that migraine patients had lower adherence to the MD compared to the controls and that the HIT-6 scale had a significant negative relationship with MD adherence in patients with high-frequency episodic and chronic migraine. Additionally, in the same migraine patients, the presence of sleep-wake disturbances was correlated with greater migraine disability as assessed by the MIDAS score. In conclusion, this study found that among different lifestyle factors, poor adherence to the MD and the presence of sleep-wake disturbances were closely associated with migraine disability and chronification.

Early effect of onabotulinumtoxinA on EEG-based functional connectivity in patients with chronic migraine: A pilot study

OBJECTIVE

In this pilot prospective cohort study, we aimed to evaluate, using high-density electroencephalography (HD-EEG), the longitudinal changes in functional connectivity (FC) in patients with chronic migraine (CM) treated with onabotulinumtoxinA (OBTA).

BACKGROUND

OBTA is a treatment for CM. Several studies have shown the modulatory action of OBTA on the central nervous system; however, research on migraine is limited.

METHODS

This study was conducted at the Neurology Unit of "Policlinico Tor Vergata," Rome, Italy, and included 12 adult patients with CM treated with OBTA and 15 healthy controls (HC). Patients underwent clinical scales at enrollment (T0) and 3 months (T1) from the start of treatment. HD-EEG was recorded using a 64-channel system in patients with CM at T0 and T1. A source reconstruction method was used to identify brain activity. FC in δ-θ-α-β-low-γ bands was analyzed using the weighted phase-lag index. FC changes between HCs and CM at T0 and T1 were assessed using cross-validation methods to estimate the results' reliability.

RESULTS

Compared to HCs at T0, patients with CM showed hyperconnected networks in δ (p = 0.046, area under the receiver operating characteristic curve [AUC: 0.76-0.98], Cohen's κ [0.65-0.93]) and β (p = 0.031, AUC [0.68-0.95], Cohen's κ [0.51-0.84]), mainly involving orbitofrontal, occipital, temporal pole and orbitofrontal, superior temporal, occipital, cingulate areas, and hypoconnected networks in α band (p = 0.029, AUC [0.80-0.99], Cohen's κ [0.42-0.77]), predominantly involving cingulate, temporal pole, and precuneus. Patients with CM at T1, compared to T0, showed hypoconnected networks in δ band (p = 0.032, AUC [0.73-0.99], Cohen's κ [0.53-0.90]) and hyperconnected networks in α band (p = 0.048, AUC [0.58-0.93], Cohen's κ [0.37-0.78]), involving the sensorimotor, orbitofrontal, cingulate, and temporal cortex.

CONCLUSION

These preliminary results showed that patients with CM presented disrupted EEG-FC compared to controls restored by a single session of OBTA treatment, suggesting a primary central modulatory action of OBTA.

The Positive and Negative Predictive Value of Targeted Diagnostic Botox Injection in Nerve Decompression Migraine Surgery

BACKGROUND

Nerve decompression surgery is an effective treatment modality for patients who experience migraines. Botulinum toxin type A (Botox) injections have been traditionally used as a method to identify trigger sites; however, there is a paucity in data regarding its diagnostic efficacy. The goal of this study was to assess the diagnostic capacity of Botox in successfully identifying migraine trigger sites and predicting surgical success.

METHODS

A sensitivity analysis was performed on all patients receiving Botox for migraine trigger site localization followed by a surgical decompression of affected peripheral nerves. Positive and negative predictive values were calculated.

RESULTS

A total of 40 patients met our inclusion criteria and underwent targeted diagnostic Botox injection followed by a peripheral nerve deactivation surgery with at least 3 months' follow-up. Patients with successful Botox injections (defined as at least 50% improvement in Migraine Headache Index scores after injection) had significantly higher average reduction in migraine intensity (56.7% versus 25.8%; P = 0.020), frequency (78.1% versus 46.8%; P = 0.018), and Migraine Headache Index (89.7% versus 49.2%; P = 0.016) postsurgical deactivation. Sensitivity analysis shows that the use of Botox injection as a diagnostic modality for migraine headaches has a sensitivity of 56.7% and a specificity of 80.0%. The positive predictive value is 89.5% and the negative predictive value is 38.1%.

CONCLUSIONS

Diagnostic targeted Botox injections have a very high positive predictive value. It is therefore a useful diagnostic modality that can help identify migraine trigger sites and improve preoperative patient selection.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Diagnostic, II.

Treatment Options for Posttraumatic Headache: A Current Review of the Literature

PURPOSE OF REVIEW

We evaluate evidence-based treatments for posttraumatic headache (PTH), a secondary headache disorder resulting from traumatic brain injury (TBI), comprising nearly 4% of all symptomatic headache disorders. Utilizing recent publications, we aim to inform clinicians of current treatment methods.

RECENT FINDINGS

There is limited research on PTH treatment. A randomized controlled trial (RCT) of metoclopramide with diphenhydramine for acute PTH found that the treatment group (N = 81) experienced more significant pain improvement than placebo by 1.4 points. For persistent PTH, an open-label study of erenumab (N = 89) found that 28% of participants reported ≥ 50% reduction in moderate-to-severe headache days, but an RCT of fremanezumab showed a non-significant reduction in moderate-to-severe headache days. A randomized crossover study of 40 patients with persistent PTH found that onabotulinum toxin-A decreased cumulative number of headaches/week by 43.3% in the treatment group and increased by 35.1% among placebos. In a study of military veterans with severe posttraumatic stress disorder and persistent/delayed onset PTH (N = 193), patients who received Cognitive Behavioral Therapy reported significant improvements in headache-related disability compared to usual care (aggregate mean HIT-6, -3.4). A transcranial magnetic stimulation (N = 24) study found that 58% of participants with mild TBI-related headache experienced a 50% reduction in headache frequency. New studies indicate promise in improving clinically important outcomes of PTH. However, more research is necessary to determine the optimal treatment and whether combining pharmacologic and nonpharmacologic treatment versus a single modality is more effective.

Neuromodulation Techniques for Headache Management

This narrative review aims to summarize evidence regarding the current utilization and future applications of neuromodulation in patients with headaches, with special attention paid to migraine and chronic cluster headache. A search was conducted in PubMed in August of 2023 to survey the current literature on neuromodulation for the treatment of headache. In total, the search yielded 1989 results, which were further filtered to include only systematic reviews published between 2022 to 2023 to capture the most up-to-date and comprehensive research on this topic. The citation lists of these articles were reviewed to find additional research on neuromodulation and supplement the results presented in this paper with primary literature. Research on the use of neuromodulation for the treatment of headache has predominantly focused on four neuromodulation techniques: peripheral nerve stimulation (PNS), transcranial magnetic stimulation (TMS), deep brain stimulation (DBS), and spinal cord stimulation (SCS). Outcome measures reported in this article include impact on migraine and headache frequency and/or pain intensity, adverse effects of the neuromodulation technique, and associated costs, when available. We found that neuromodulation has developed utility as an alternative treatment for both chronic cluster headaches and migraines, with a reduction in frequency and intensity of headache most elucidated from the articles mentioned in this review.

Relative Pain Reduction and Duration of Nerve Block Response Predict Outcomes in Headache Surgery: A Prospective Cohort Study

BACKGROUND

Experts agree that nerve block (NB) response is an important tool in headache surgery screening. However, the predictive value of NBs remains to be proven in a prospective fashion.

METHODS

Pre-NB and post-NB visual analogue pain scores (0 to 10) and duration of NB response were recorded prospectively. Surgical outcomes were recorded prospectively by calculating the Migraine Headache Index (MHI) preoperatively and postoperatively at 3 months, 12 months, and every year thereafter.

RESULTS

The study population included 115 patients. The chance of achieving MHI percentage improvement of 80% or higher was significantly higher in subjects who reported relative pain reduction of greater than 60% following NB versus less than or equal to 60% [63 of 92 (68.5%) versus 10 of 23 (43.5%); P = 0.03]. Patients were more likely to improve their MHI 50% or more with relative pain reduction of greater than 40% versus 40% or less [82 of 104 (78.8%) versus five of 11 (45.5%); P = 0.01]. In subjects with NB response of greater than 15 days, 10 of 13 patients (77.0%) experienced MHI improvement of 80% or greater. Notably, all of these patients (100%) reported MHI improvement of 50% or greater, with mean MHI improvement of 88%. Subjects with a NB response of 24 hours or more achieved significantly better outcomes than patients with a shorter response (72.7% ± 37.0% versus 46.1% ± 39.7%; P = 0.02). However, of 14 patients reporting NB response of less than 24 hours, four patients had MHI improvement of 80% or greater, and seven, of 50% or greater.

CONCLUSIONS

Relative pain reduction and duration of NB response are predictors of MHI improvement after headache surgery. NBs are a valuable tool to identify patients who will benefit from surgery.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Neurovascular Compression-Induced Intracranial Allodynia May Be the True Nature of Migraine Headache: an Interpretative Review

PURPOSE OF REVIEW

Surgical deactivation of migraine trigger sites by extracranial neurovascular decompression has produced encouraging results and challenged previous understanding of primary headaches. However, there is a lack of in-depth discussions on the pathophysiological basis of migraine surgery. This narrative review provides interpretation of relevant literature from the perspective of compressive neuropathic etiology, pathogenesis, and pathophysiology of migraine.

RECENT FINDINGS

Vasodilation, which can be asymptomatic in healthy subjects, may produce compression of cranial nerves in migraineurs at both extracranial and intracranial entrapment-prone sites. This may be predetermined by inherited and acquired anatomical factors and may include double crush-type lesions. Neurovascular compression can lead to sensitization of the trigeminal pathways and resultant cephalic hypersensitivity. While descending (central) trigeminal activation is possible, symptomatic intracranial sensitization can probably only occur in subjects who develop neurovascular entrapment of cranial nerves, which can explain why migraine does not invariably afflict everyone. Nerve compression-induced focal neuroinflammation and sensitization of any cranial nerve may neurogenically spread to other cranial nerves, which can explain the clinical complexity of migraine. Trigger dose-dependent alternating intensity of sensitization and its synchrony with cyclic central neural activities, including asymmetric nasal vasomotor oscillations, may explain the laterality and phasic nature of migraine pain. Intracranial allodynia, i.e., pain sensation upon non-painful stimulation, may better explain migraine pain than merely nociceptive mechanisms, because migraine cannot be associated with considerable intracranial structural changes and consequent painful stimuli. Understanding migraine as an intracranial allodynia could stimulate research aimed at elucidating the possible neuropathic compressive etiology of migraine and other primary headaches.

Mechanism and clinical use of botulinum neurotoxin in head and facial region

PURPOSE

Botulinum neurotoxin (BoNT) is a biological toxin produced by Clostridium botulinum. BoNT is a potent toxin extensively used in therapeutic interventions. This review provides an updated overview of the mechanisms of action and clinical applications of BoNT in head and facial region.

STUDY SELECTION

MEDLINE/PubMed searches were conducted using the terms "botulinum neurotoxin" and "dentistry" along with a combination of other related terms. In addition, studies were manually selected from reference lists of the selected articles.

RESULTS

The Food and Drug Administration in the United States initially approved BoNT to treat strabismus, blepharospasm, and hemifacial spasms. The use of BoNT in dermatology and cosmetics has been widely established and has created a revolution in these fields. Over the years, its applications in various medical specialties have expanded widely. Owing to its safety, efficacy, and long duration of action, it is well-accepted by patients. BoNT/A and BoNT/B are widely used in clinical practice. Several off-label uses of BoNT in the dental fraternity have yielded promising results. We have elaborated on the speculated mechanism of action, dosage, effective sites of injection, and adverse effects of each therapeutic application. The various clinical indications for BoNT include bruxism, myofascial pain, temporomandibular joint dislocation, hemifacial pain, orofacial dystonia, facial paralysis, chronic migraine, and trigeminal neuralgia.

CONCLUSIONS

BoNT is a safe treatment that can be used effectively, provided that the clinician has adequate knowledge regarding the mechanism, injection techniques, and local and systemic side effects and that it is administered cautiously and purposefully.

Headache frequency and neck pain are associated with trapezius muscle T2 in tension-type headache among young adults

BACKGROUND

Tension-type headache (TTH) is the most prevalent primary headache disorder. Neck pain is commonly associated with primary headaches and the trigemino-cervical complex (TCC) refers to the convergence of trigeminal and cervical afferents onto neurons of the brainstem, thus conceptualizes the emergence of headache in relation to neck pain. However, no objective biomarkers exist for the myofascial involvement in primary headaches. This study aimed to investigate the involvement of the trapezius muscles in primary headache disorders by quantitative magnetic resonance imaging (MRI), and to explore associations between muscle T2 values and headache frequency and neck pain.

METHODS

This cohort study prospectively enrolled fifty participants (41 females, age range 20-31 years): 16 subjects with TTH only (TTH-), 12 with mixed-type TTH plus migraine (TTH+), and 22 healthy controls (HC). The participants completed fat-suppressed T2-prepared three-dimensional turbo spin-echo MRI, a headache diary (over 30 days prior to MRI), manual palpation (two weeks before MRI), and evaluation of neck pain (on the day of MRI). The bilateral trapezius muscles were manually segmented, followed by muscle T2 extraction. Associations between muscle T2 and the presence of neck pain as well as the number of days with headache (considering the 30 days prior to imaging using the headache calendar) were analyzed using regression models (adjusting for age, sex, and body mass index).

RESULTS

The TTH+ group demonstrated the highest muscle T2 values (right side: 31.4 ± 1.2 ms, left side: 31.4 ± 0.8 ms) as compared to the TTH- group or HC group (p < 0.001). Muscle T2 was significantly associated with the number of headache days (β-coefficient: 2.04, p = 0.04) and the presence of neck pain (odds ratio: 2.26, p = 0.04). With muscle T2 as the predictor, the area under the curve for differentiating between HC and the TTH+ group was 0.82.

CONCLUSIONS

Increased T2 of trapezius muscles may represent an objective imaging biomarker for myofascial involvement in primary headache disorders, which could help to improve patient phenotyping and therapy evaluation. Pathophysiologically, the increased muscle T2 values could be interpreted as a surrogate of neurogenic inflammation and peripheral sensitization within myofascial tissues.

The Surgical Management of Migraines and Chronic Headaches: A Cross-sectional Review of American Insurance Coverage

BACKGROUND

Migraine headache can be an extremely debilitating condition, with pharmacotherapy for prophylaxis or treatment of acute symptoms being unsuccessful in a large proportion of patients. Surgical management of migraine has recently gained popularity as an alternative to pharmacotherapy for severe disease. However, the novel nature of these procedures may lead to variable insurance coverage, limiting access to care.

METHODS

A cross-sectional analysis of 101 US insurance companies was conducted. Companies were chosen based on greatest market share and enrollment per state. A Web-based search or phone call identified whether each company had a publicly available policy on nonsurgical or surgical management of migraine or headache. For companies with an available policy, coverage was categorized into covered, covered on a case-by-case basis, or never covered, with criteria required for coverage collected and categorized.

RESULTS

Of the 101 evaluated insurers, significantly fewer companies had a policy on surgical treatment for migraine or headache (n = 52 [52%]) compared with nonsurgical treatment (n = 78 [78%]) (P < 0.001). For companies with a policy, the most frequently covered nonsurgical treatments were biofeedback (n = 23 [92%]) and botulism toxin injections (n = 61 [88%]). Headaches were an approved indication for occipital nerve stimulation in 4% (n = 2) of company policies and nerve decompression in 2% (n = 1) of policies. Migraines were never offered preauthorized coverage for surgical procedures.

CONCLUSION

Approximately half of US insurance companies have a publicly available policy on surgical management of migraine or headache. Surgical treatment was seldom covered for the indication of headache and would never receive preauthorized coverage for migraine. Lack of coverage may create challenges in accessing surgical treatment. Additional prospective, controlled studies are necessary to further support the efficacy of surgical treatment.

Regional Targeted Subcutaneous Injection of Botulinum Neurotoxin Type A in Refractory Chronic Migraine: A Randomized, Double-Blind, Placebo-Controlled Study

In this randomized, double-blind, placebo-controlled study, we evaluated the efficacy of an individualized technique of subcutaneous injection of botulinum toxin type A (BoNT-A) targeted (SjBoT) to the occipital or trigeminal skin area in non-responder patients with chronic migraine (CM). Patients who had not previously responded to at least two treatments of intramuscular injections of BoNT-A were randomly assigned (2:1) to receive two subcutaneous administrations of BoNT-A (up to 200 units) with the SjBoT injection paradigm or placebo. Following the skin area where the maximum pain began, treatment was given in the trigeminal or occipital region bilaterally. The primary endpoint changed in monthly headache days from baseline to the last 4 weeks. Among 139 randomized patients, 90 received BoNT-A and 49 received placebo, and 128 completed the double-blind phase. BoNT-A significantly reduced monthly headache days versus placebo (-13.2 versus -1.2; p < 0.0001) in the majority of patients who had cutaneous allodynia. Other secondary endpoints, including measures for disability (Migraine Disability Assessment questionnaire from baseline 21.96 to 7.59 after treatment, p = 0.028), also differed. Thus, in non-responder patients with CM, BoNT-A significantly reduced migraine days when administered according to the "follow the origin of maximum pain" approach using SjBoT injection paradigm.

Novel Treatments for Chronic Ocular Surface Pain

ABSTRACT

Several etiologies can contribute to ocular surface pain including nociceptive, peripheral neuropathic, and central neuropathic mechanisms. Clinical clues can help identify contributors to ocular surface pain in a patient. In individuals whose pain persists despite targeting nociceptive contributors, neuropathic mechanisms should be considered and addressed using oral, topical, and/or adjuvant agents.

Effects of Botulinum Toxin Type A on the Nociceptive and Lemniscal Somatosensory Systems in Chronic Migraine: An Electrophysiological Study

(1) Background: OnabotulinumtoxinA (BoNT-A) is a commonly used prophylactic treatment for chronic migraine (CM). Although randomized placebo studies have shown its clinical efficacy, the mechanisms by which it exerts its therapeutic effect are still incompletely understood and debated. (2) Methods: We studied in 15 CM patients the cephalic and extracephalic nociceptive and lemniscal sensory systems using electrophysiological techniques before and 1 and 3 months after one session of pericranial BoNT-A injections according to the PREEMPT protocol. We recorded the nociceptive blink reflex (nBR), the trigemino-cervical reflex (nTCR), the pain-related cortical evoked potential (PREP), and the upper limb somatosensory evoked potential (SSEP). (3) Results: Three months after a single session of prophylactic therapy with BoNT-A in CM patients, we found (a) an increase in the homolateral and contralateral nBR AUC, (b) an enhancement of the contralateral nBR AUC habituation slope and the nTCR habituation slope, (c) a decrease in PREP N-P 1st and 2nd amplitude block, and (d) no effect on SSEPs. (4) Conclusions: Our study provides electrophysiological evidence for the ability of a single session of BoNT-A injections to exert a neuromodulatory effect at the level of trigeminal system through a reduction in input from meningeal and other trigeminovascular nociceptors. Moreover, by reducing activity in cortical pain processing areas, BoNT-A restores normal functioning of the descending pain modulation systems.

Bipartite Activation of Sensory Neurons by a TRPA1 Agonist Allyl Isothiocyanate Is Reflected by Complex Ca2+ Influx and CGRP Release Patterns: Enhancement by NGF and Inhibition with VAMP and SNAP-25 Cleaving Botulinum Neurotoxins

The trafficking of transient receptor potential (TRP) channels to the plasma membrane and the release of calcitonin gene-related peptide (CGRP) from trigeminal ganglion neurons (TGNs) are implicated in some aspects of chronic migraines. These exocytotic processes are inhibited by cleavage of SNAREs with botulinum neurotoxins (BoNTs); moreover, type A toxin (/A) clinically reduces the frequency and severity of migraine attacks but not in all patients for unknown reasons. Herein, neonatal rat TGNs were stimulated with allyl isothiocyanate (AITC), a TRPA1 agonist, and dose relationships were established to link the resultant exocytosis of CGRP with Ca2+ influx. The CGRP release, quantified by ELISA, was best fit by a two-site model (EC50 of 6 and 93 µM) that correlates with elevations in intracellular Ca2+ [Ca2+]i revealed by time-lapse confocal microscopy of fluo-4-acetoxymethyl ester (Fluo-4 AM) loaded cells. These signals were all blocked by two TRPA1 antagonists, HC-030031 and A967079. At low [AITC], [Ca2+]i was limited because of desensitisation to the agonist but rose for concentrations > 0.1 mM due to a deduced non-desensitising second phase of Ca2+ influx. A recombinant BoNT chimera (/DA), which cleaves VAMP1/2/3, inhibited AITC-elicited CGRP release to a greater extent than SNAP-25-cleaving BoNT/A. /DA also proved more efficacious against CGRP efflux evoked by a TRPV1 agonist, capsaicin. Nerve growth factor (NGF), a pain-inducing sensitiser of TGNs, enhanced the CGRP exocytosis induced by low [AITC] only. Both toxins blocked NGF-induced neuropeptide secretion and its enhancement of the response to AITC. In conclusion, NGF sensitisation of sensory neurons involves TRPA1, elevated Ca2+ influx, and CGRP exocytosis, mediated by VAMP1/2/3 and SNAP-25 which can be attenuated by the BoNTs.

[Botulinum toxin type A (Relatox) in the treatment of chronic migraine in adults: results of phase IIIb, randomized, one-blind, multicenter, active-controlled, parallel-group trial]

OBJECTIVE

To access the efficacy and safety of the first Russian botulinum toxin type A (Relatox) as a headache prophylaxis in adult with chronic migraine (CM).

MATERIAL AND METHODS

The randomized, one-blind, multicenter, active-controlled, parallel-group trial study involved 209 patients with CM aged from 19 to 65 years. The patients were randomized to injections of the Russian botulinum toxin type A - Relatox (n=101) or onabotulinumtoxinA injections - Botox (n=108). The duration of the study was 16 weeks, which included five visits of patients every 4 weeks. Relatox and Botox were injected once into seven muscle groups of the head and neck at a dose of 155-195 units. Primary efficacy variable was mean change from baseline in frequency of headache days after 12 weeks. Secondary efficacy variables were mean changes from the baseline to week 12 in frequency of migraine days, acute headache pain medication intakes days; headache intensity; proportion of patients achieving ≥50% reduction from baseline in headache days, the proportion of the patients with medication overuse, the proportion of the patients with severe (≥60) Headache Impact Test-6 score and with a severe (≥21) MIDAS score.

RESULTS

Analyses demonstrated a large mean decrease from baseline in frequency of headache days, without statistically significant between-group differences Relatox vs Botox at week 12 (-10.89 vs -10.06; p=0.365) and at other time points. Significant differences from baseline were also observed for all secondary efficacy variables at all time points without differences between the groups. The proportion of patients achieving ≥50% reduction from baseline in headache days was 75.0% and 70% in the Relatox and Botox groups, respectively (OR, CI 95% 1.58 [0.84; 3.02], p=0.155). Adverse events (AE) occurred in 15.8% of Relatox patients and 15.7% of Botox patients (p=1.000). No unexpected AE were identified.

CONCLUSION

The results demonstrate that the first Russian botulinum toxin type A (Relatox) is an effective prophylactic treatment for CM in adult patients. Relatox led to significant improvements from baseline in multiple measures of headache symptoms, headache-related disability and quality of life. For the first time, a comparative analysis of two botulinum toxin type A products in parallel groups showed no less (not inferior) efficacy and safety of Relatox relative to Botox in the treatment of CM in adults.

Review of Tolerability of Fremanezumab for Episodic and Chronic Migraine

Calcitonin gene-related peptide (CGRP) monoclonal antibodies (mAbs) were the first class of medication specifically developed for the prevention of migraine. Fremanezumab is one of four CGRP mAbs currently available and is approved by the US Food and Drug Administration (FDA) for the preventative treatment of episodic and chronic migraines. This narrative review summarizes the history of fremanezumab development, the trials that led to its approval, and the later studies published evaluating its tolerability and efficacy. Evidence of fremanezumab for clinically significant efficacy and tolerability in patients with chronic migraine is especially important when considering the high level of disability, lower quality of life scores, and higher levels of health-care utilization associated with this condition. Multiple clinical trials demonstrated superiority of fremanezumab over placebo in terms of efficacy while demonstrating good tolerability. Treatment-related adverse reactions did not differ significantly compared to placebo and dropout rates were minimal. The most commonly observed treatment-related adverse reaction was mild-to-moderate injection site reaction, described as erythema, pain, induration, or swelling at the injection site.

OnabotulinumtoxinA Modulates Visual Cortical Excitability in Chronic Migraine: Effects of 12-Week Treatment

Chronic migraine is a burdensome disease presenting with episodic pain and several symptoms that may persist even among headache attacks. Multisensory integration is modified in migraine, as assessed by the level of the perception of sound-induced flash illusions, a simple paradigm reflecting changes in cortical excitability which reveals to be altered in migraineurs. OnabotulinumtoxinA is an effective preventive therapy for chronic migraineurs, reducing peripheral and central sensitization, and may influence cortical excitability. Patients affected by chronic migraine who started onabotulinumtoxinA preventive therapy were included. Clinical effects (headache diaries and migraine related questionnaires) were assessed at the beginning of the therapy and after 12 weeks. Contextually, patients underwent the evaluation of multisensory perception by means of the sound-induced flash illusions. OnabotulinumtoxinA showed effectiveness both in migraine prevention and in reducing headache burden. Even one session of therapy was able to restore, at least partially, multisensory processing, as shown by patients' susceptibility to the sound-induced flash illusion. OnabotulinumtoxinA could influence migraineurs cortical excitability concurrently to the beneficial effects in headache prevention.

The Development of Psychiatric Illness and Chemoprophylaxis of Botulinum Toxin in Migraine: A Narrative Review

A migraine is not just a headache. It is an extremely prevalent neurological condition marked by periodic episodes of unilateral headache, with more than 10 million cases yearly. Migraine often begins at the age of puberty. It substantially impacts the brain and, consequently, psychiatric behavior linked with frequent migraine attacks that may be moderate to severe in intensity. A crucial aspect of migraine variability is comorbidity with other neurological diseases, vascular diseases, and mental illnesses. Psychiatric disorders related to migraine include anxiety disorders, panic disorder, bipolar disorder, depression, etc. It is also estimated that people suffering from migraine are about five times more likely to develop depression than others without migraine. The stimulus for migraine is stress, lack of sleep, skipped meal or fasting, visual stimulation due to high intensity of light, auditory stimulus due to noise, and olfactory stimulus due to a pungent smell. A majority of patients suffer from migraine attacks triggered by noise, some due to visual stimulation, and a few due to perfumes or other odors that trigger their migraine. Diagnosis of this is primarily dependent on history taking and clinical evaluation. Migraine can be classified depending on whether an aura is present or absent. It can further be divided based on the frequency of headaches into episodic migraine or chronic migraine, which may be determined by the duration of the headache. The development of migraine is influenced by both genetics and the environment. It has a detrimental effect on children's quality of life. A comprehensive analysis of psychiatric illnesses in migraine contributes to early diagnosis and proper treatment of the disease. Also, having a healthy lifestyle (including exercise, a balanced diet, and enough sleep) seems to prevent and improve the condition. Headache in migraine is resistant to medical treatment but responds well to botulinum toxin. This review primarily focuses on the psychiatric issues like depression and anxiety that often accompany migraine. The article also highlights the effects of botulinum toxin on migraine.

Glutamatergic systems in neuropathic pain and emerging non-opioid therapies

Neuropathic pain, a disease of the somatosensory nervous system, afflicts many individuals and adequate management with current pharmacotherapies remains elusive. The glutamatergic system of neurons, receptors and transporters are intimately involved in pain but, to date, there have been few drugs developed that therapeutically modulate this system. Glutamate transporters, or excitatory amino acid transporters (EAATs), remove excess glutamate around pain transmitting neurons to decrease nociception suggesting that the modulation of glutamate transporters may represent a novel approach to the treatment of pain. This review highlights and summarizes (1) the physiology of the glutamatergic system in neuropathic pain, (2) the preclinical evidence for dysregulation of glutamate transport in animal pain models, and (3) emerging novel therapies that modulate glutamate transporters. Successful drug discovery requires continuous focus on basic and translational methods to fully elucidate the etiologies of this disease to enable the development of targeted therapies. Increasing the efficacy of astrocytic EAATs may serve as a new way to successfully treat those suffering from this devastating disease.

Botulinum Toxin—A Current Place in the Treatment of Chronic Migraine and Other Primary Headaches

Headaches are a very common condition that most people will experience many times during their lives. This article presents the primary headaches, which are a large group of diseases where the headache is not a symptom of another known disease. Tension-type headache affects approximately 80% of the general population, and the prevalence of migraine is estimated at 10–12%. Clinical data and experience to date have demonstrated that botulinum toxin may be an effective prophylactic treatment for chronic headache types. It has been used in neurology for the treatment of dystonia and blepharospasm. Now it has been approved to treat chronic migraine and has been shown to confer significant benefit in refractory cases. Based on clinical experience botulinum toxin has also been tried in other headache disorders. While it is intuitively attractive to think that due to its effect on pain by sensory modulation, there may also be efficacy in its use in chronic tension-type headache and cluster headache, so far, there is little evidence to support this. Botulinum toxin is effective in pain control through its interaction with the SNARE complex, which inhibits the release of neurotransmitters, such as glutamate, substance P and calcitonin gene-related peptide. OnabotulinumtoxinA is effective not only in headache frequency and pain intensity but in other parameters, including quality of life.

Recently approved and emerging drug options for migraine prophylaxis

INTRODUCTION

: Migraine occupies the first position regarding to the disability caused in female working population (15-49 years). Research in the field of prophylaxis of this pathology has made enormous strides in recent years.

AREAS COVERED

In this narrative review we retrace the most important scientific evidence regarding recently approved and emerging drug for prophylactic treatment of migraine. The purpose of this article is in fact to evaluate currently approved or emerging pharmacological agents for migraine prophylaxis. This review is based on literature published in peer review journal obtained through PubMed, Cochrane library, Clinicaltrials.gov and US FDA.

EXPERT OPINION

: Monoclonal antibodies (mAbs) that target the calcitonin gene-related peptide signalling pathway (CGRP) have marked an innovation in prophylactic migraine therapy. The combination of Onabotulinumtoxin-A (OBTA) and mAbs appears to be an effective, but costly, therapeutic option for resistant cases. New classes of molecules like gepants and ditans seem to give exceptional results. In addition, new prophylactic drugs are emerging with several targets: the pituitary adenylate cyclase-activating polypeptide (PACAP), ion channels, several receptors coupled to G proteins, orexin, and glutamate. All these therapies will implement and improve migraine management, as well as personalized medicine for each patient.

Effects of onabotulinumtoxin A in patients concurrently diagnosed with chronic migraine encephalalgia and temporomandibular disorders: A retrospective case series

OBJECTIVE

Chronic migraine encephalalgia (CME) with concomitant temporomandibular disorder (TMD) is a serious illness with limited effective treatment options. This study explores the effectiveness of onabotulinumtoxinA (BtxA) as an adjunct therapeutic to TMJ arthroscopy in the relief of CME.

METHODS

A retrospective cohort study of patients receiving TMJ arthroscopy, with or without BtxA injections for CME, was conducted. Variables assessed include pain using a visual analog scale (VAS), maximal incisal opening (MIO), muscle soreness, and headache frequency and duration.

RESULTS

Sixty patients (44 BtxA, 16 Control), consisting of 56 (93.3%) females, met inclusion criteria. A significant reduction in pain is reported with patients receiving BtxA (p < 0.0001) on VAS as compared to Control group. BtxA treatment also significantly reduced headache frequency and duration (p < 0.05).

CONCLUSION

These results support the use of adjunctive BtxA treatment with arthroscopy for the treatment of CME in the context of TMD.

NGF Enhances CGRP Release Evoked by Capsaicin from Rat Trigeminal Neurons: Differential Inhibition by SNAP-25-Cleaving Proteases

Nerve growth factor (NGF) is known to intensify pain in various ways, so perturbing pertinent effects without negating its essential influences on neuronal functions could help the search for much-needed analgesics. Towards this goal, cultured neurons from neonatal rat trigeminal ganglia—a locus for craniofacial sensory nerves—were used to examine how NGF affects the Ca²⁺-dependent release of a pain mediator, calcitonin gene-related peptide (CGRP), that is triggered by activating a key signal transducer, transient receptor potential vanilloid 1 (TRPV1) with capsaicin (CAP). Measurements utilised neurons fed with or deprived of NGF for 2 days. Acute re-introduction of NGF induced Ca²⁺-dependent CGRP exocytosis that was inhibited by botulinum neurotoxin type A (BoNT/A) or a chimera of/E and/A (/EA), which truncated SNAP-25 (synaptosomal-associated protein with Mr = 25 k) at distinct sites. NGF additionally caused a Ca²⁺-independent enhancement of the neuropeptide release evoked by low concentrations (<100 nM) of CAP, but only marginally increased the peak response to ≥100 nM. Notably, BoNT/A inhibited CGRP exocytosis evoked by low but not high CAP concentrations, whereas/EA effectively reduced responses up to 1 µM CAP and inhibited to a greater extent its enhancement by NGF. In addition to establishing that sensitisation of sensory neurons to CAP by NGF is dependent on SNARE-mediated membrane fusion, insights were gleaned into the differential ability of two regions in the C-terminus of SNAP-25 (181–197 and 198–206) to support CAP-evoked Ca²⁺-dependent exocytosis at different intensities of stimulation.

Editorial on the Special Issue "Botulinum Toxin for the Treatment of Neurological Disorders: Where We Are and Where We Need to Go"

Over the past 30 years, botulinum toxin (BoNT) has seen an ever-expanding use in disorders afflicting the nervous system [...].

Selective Expression of a SNARE-Cleaving Protease in Peripheral Sensory Neurons Attenuates Pain-Related Gene Transcription and Neuropeptide Release

Chronic pain is a leading health and socioeconomic problem and an unmet need exists for long-lasting analgesics. SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) are required for neuropeptide release and noxious signal transducer surface trafficking, thus, selective expression of the SNARE-cleaving light-chain protease of botulinum neurotoxin A (LCA) in peripheral sensory neurons could alleviate chronic pain. However, a safety concern to this approach is the lack of a sensory neuronal promoter to prevent the expression of LCA in the central nervous system. Towards this, we exploit the unique characteristics of Pirt (phosphoinositide-interacting regulator of TRP), which is expressed in peripheral nociceptive neurons. For the first time, we identified a Pirt promoter element and cloned it into a lentiviral vector driving transgene expression selectively in peripheral sensory neurons. Pirt promoter driven-LCA expression yielded rapid and concentration-dependent cleavage of SNAP-25 in cultured sensory neurons. Moreover, the transcripts of pain-related genes (TAC1, tachykinin precursor 1; CALCB, calcitonin gene-related peptide 2; HTR3A, 5-hydroxytryptamine receptor 3A; NPY2R, neuropeptide Y receptor Y2; GPR52, G protein-coupled receptor 52; SCN9A, sodium voltage-gated channel alpha subunit 9; TRPV1 and TRPA1, transient receptor potential cation channel subfamily V member 1 and subfamily A member 1) in pro-inflammatory cytokines stimulated sensory neurons were downregulated by viral mediated expression of LCA. Furthermore, viral expression of LCA yielded long-lasting inhibition of pain mediator release. Thus, we show that the engineered Pirt-LCA virus may provide a novel means for long lasting pain relief.