Spreading depression (SD) is a slowly propagating wave of near-complete depolarization of neurons and glial cells across the cortex. SD is thought to contribute to the underlying pathophysiology of ...migraine aura, and possibly also an intrinsic brain activity causing migraine headache. Experimental models of SD have recapitulated multiple migraine-related phenomena and are considered highly translational. In this review, we summarize conventional and novel methods to trigger SD, with specific focus on optogenetic methods. We outline physiological triggers that might affect SD susceptibility, review a multitude of physiological, biochemical, and behavioral consequences of SD, and elaborate their relevance to migraine pathophysiology. The possibility of constructing a recurrent episodic or chronic migraine model using SD is also discussed.
Cortical spreading depolarisation (CSD), the neural mechanism underlying migraine aura, may cause headache by sensitising the trigeminal system. Photophobia, the most bothersome accompanying symptom ...during migraine attacks, is more prevalent in migraine with aura than in migraine without aura. Whether CSD plays a role in developing photophobia remains unknown. Moreover, migraine-induced physical hypoactivity contributes to loss of productivity. We aimed to investigate the development of trigeminal sensitisation, photophobia and locomotive abnormality after KCl-induced CSD using 86 male C57BL/6 mice. Sham-operated mice were used as controls. We confirmed the presence of trigeminal sensitisation and photophobia at 24 h after CSD. CSD-subjected mice also exhibited significantly reduced locomotive activity in both light and dark zones. Hence, the CSD-induced hypomobility was likely to be independent of photophobia. The 5-HT
agonist, sumatriptan, corrected all these CSD-induced abnormalities. Moreover, dose dependency was demonstrated in the ameliorating effect of the calcitonin gene-related peptide (CGRP) receptor antagonist, olcegepant, on these abnormalities. Sumatriptan and olcegepant improved mouse locomotion with therapeutic lags ranging from 20 to 30 min. Collectively, CSD caused trigeminal sensitisation, photophobia and hypomobility that persisted for at least 24 h by a mechanism involving the 5-HT
and CGRP activity.
Objective
Headache disorders like migraine show geographic and ethnic differences between Asian and European/North American countries. In cluster headache, these differences are rarely mentioned and ...discussed. This article aimed to review the characteristics of cluster headache in Asian countries and compare the clinical features to those in European and North American populations.
Methods
We conducted a narrative literature review on the demographics, clinical presentations, and treatments of cluster headache in Asian countries.
Results
Patients with cluster headache in Asian populations showed a stronger male predominance compared to European and North American populations. Chronic cluster headache was rare in Asian countries. The clinical presentation of restlessness was not as common in Asian as it was in European and North American countries, and Asian patients with aura were extremely rare. Patients in Asian countries may have a lower circadian rhythmicity of cluster headache and a lower headache load, as demonstrated by lower attack frequencies per day, bout frequencies, and bout durations.
Conclusions
Regional differences in the presentation of cluster headache exist. Greater awareness for cluster headache should be raised in Asian regions, and further studies are warranted to elucidate the mechanisms behind observed differences.
Objective
Cortical spreading depression (SD) is an intense depolarization underlying migraine aura. Despite the weight of evidence linking SD to the pain phase of migraine, controversy remains over a ...causal role of SD in cephalgia because of the invasive nature of previous SD induction methods. To overcome this problem, we used a novel minimally invasive optogenetic SD induction method and examined the effect of SD on behavior.
Methods
Optogenetic SD was induced as a single event or repeatedly every other day for 2 weeks. End points, including periorbital and hindpaw mechanical allodynia, mouse grimace, anxiety, and working memory, were examined in male and female mice.
Results
A single SD produced bilateral periorbital mechanical allodynia that developed within 1 hour and resolved within 2 days. Sumatriptan prevented periorbital allodynia when administered immediately after SD. Repeated SDs also produced bilateral periorbital allodynia that lasted 4 days and resolved within 2 weeks after the last SD. In contrast, the hindpaw withdrawal thresholds did not change after repeated SDs suggesting that SD‐induced allodynia was limited to the trigeminal region. Moreover, repeated SDs increased mouse grimace scores 2 days after the last SD, whereas a single SD did not. Repeated SDs also increased thigmotaxis scores as a measure of anxiety. In contrast, neither single nor repeated SDs affected visuospatial working memory. We did not detect sexual dimorphism in any end point.
Interpretation
Altogether, these data show a clinically congruent causal relationship among SD, trigeminal pain, and anxiety behavior, possibly reflecting SD modulation of hypothalamic, thalamic, and limbic mechanisms. ANN NEUROL 2021;89:99–110
Objective
Cortical spreading depolarizations (CSDs) are intense and ubiquitous depolarization waves relevant for the pathophysiology of migraine and brain injury. CSDs disrupt the blood–brain barrier ...(BBB), but the mechanisms are unknown.
Methods
A total of six CSDs were evoked over 1 hour by topical application of 300 mM of KCl or optogenetically with 470 nm (blue) LED over the right hemisphere in anesthetized mice (C57BL/6 J wild type, Thy1‐ChR2‐YFP line 18, and cav‐1–/–). BBB disruption was assessed by Evans blue (2% EB, 3 ml/kg, intra‐arterial) or dextran (200 mg/kg, fluorescein, 70,000 MW, intra‐arterial) extravasation in parietotemporal cortex at 3 to 24 hours after CSD. Endothelial cell ultrastructure was examined using transmission electron microscopy 0 to 24 hours after the same CSD protocol in order to assess vesicular trafficking, endothelial tight junctions, and pericyte integrity. Mice were treated with vehicle, isoform nonselective rho‐associated kinase (ROCK) inhibitor fasudil (10 mg/kg, intraperitoneally 30 minutes before CSD), or ROCK‐2 selective inhibitor KD025 (200 mg/kg, per oral twice‐daily for 5 doses before CSD).
Results
We show that CSD‐induced BBB opening to water and large molecules is mediated by increased endothelial transcytosis starting between 3 and 6 hours and lasting approximately 24 hours. Endothelial tight junctions, pericytes, and basement membrane remain preserved after CSDs. Moreover, we show that CSD‐induced BBB disruption is exclusively caveolin‐1–dependent and requires rho‐kinase 2 activity. Importantly, hyperoxia failed to prevent CSD‐induced BBB breakdown, suggesting that the latter is independent of tissue hypoxia.
Interpretation
Our data elucidate the mechanisms by which CSDs lead to transient BBB disruption, with diagnostic and therapeutic implications for migraine and brain injury.
Background
Long-term data helps assess the consistency of efficacy, tolerability, and safety of acute treatment over repeated use for different attacks. Real-world studies help assess tolerability, ...safety, and efficacy in patients with possibly refractory chronic migraine, more comorbidities, other diseases such as cardiovascular diseases, and polypharmacy.
Methods
This is a narrative review of the long-term open-label and real-world studies of lasmiditan, ubrogepant, and rimegepant for the acute treatment of migraine. Both manuscripts and abstracts were reviewed.
Results
The efficacy and tolerability of lasmiditan, ubrogepant, and rimegepant are maintained over time. No significant cardiovascular adverse events were thought to be related to any of these medications. The rare instances of palpitations and/or tachycardia occurred within 48 hours of lasmiditan. One participant with a history of supraventricular tachycardia had sinus tachycardia thought to be related to ubrogepant which did not recur despite continued use. One case of thrombocytopenia and two cases of increased aspartate aminotransferase and alanine transaminase were thought to be possibly related, but the alanine transaminase and aspartate aminotransferase levels normalized despite continued use of ubrogepant. A case of first-degree atrioventricular block was considered possibly related to rimegepant. Acute use of rimegepant was associated with a decrease in monthly migraine days over time. The three medications were associated with improvement in function and/or productivity.
Conclusion
Long-term and real-world data of tolerability, safety and efficacy of lasmiditan, ubrogepant, and rimegepant is thus far consistent with prior studies, but more longitudinal data that clarifies long-term safety as well as consistency and predictors of response is needed.
Myasthenia gravis (MG) is the most common autoimmune neuromuscular disorder, and is more common in women than in men. Anemia is also more common in women. The purpose of this study was to investigate ...factors associated with anemia and the negative impact of anemia in female MG patients. We investigated factors related to MG and anemia in 215 female patients with MG, who were attending the MG clinic of Keio Hospital between January and December 2021. We statistically evaluated clinical factors related to anemia in patients with and without anemia. Eighty-five patients (40%) had anemia in the past, and 130 patients did not have anemia in the past. There were no significant differences in age at study, age at MG onset, body mass index, or frequency of autoantibodies between the anemia and non-anemia groups. MG severity evaluated by the MG Foundation of America classification was greater in the anemia group than in the non-anemia group. History of anemia was associated with immunosuppressive treatment, such as prednisolone and calcineurin inhibitor treatment. There was a correlation between hemoglobin levels and the MG-quality of life score. Long term immunosuppressive therapy can cause anemia in female MG patients. Anemia may negatively affect the quality of life of female MG patients.
Goreisan, a traditional Japanese Kampo medicine, is often used to treat headaches, including migraines; however, the underlying mechanisms remain unknown. Therefore, we investigated whether chronic ...treatment with Goreisan affects cortical spreading depolarization (CSD) in migraines. CSD susceptibility was assessed in male and female C57BL/6 mice by comparing CSD threshold, propagation velocity, and CSD frequency between animals treated with Goreisan for approximately 3 weeks and the corresponding controls with a potassium-induced CSD model. No significant differences were observed in CSD susceptibility between mice that were chronically treated with Goreisan and the control mice. Additionally, no significant differences were observed in other physiological parameters, including body weight, blood gases, and blood pressure. CSD susceptibility was not affected by chronic treatment with Goreisan, which suggests that the drug treats headaches via mechanisms that do not involve CSD modulation.
Background
Clinical characteristics and treatment practice of patients with migraine in Japan in real-world setting have not been fully investigated. We conducted a retrospective cohort study using ...claims database to understand the clinical practice of migraine in recent years and to characterize patients potentially not managed well by current treatment options.
Methods
Our study used data from the large claims database maintained by JMDC Inc. Patients with diagnosis of headache or migraine between January 1, 2018, and July 31, 2022, were defined as the headache cohort, and those with migraine diagnosis and prescription of migraine treatments among the headache cohort were included in the migraine cohort. In the headache cohort, characteristics of medical facilities and status of imaging tests to distinguish secondary headache were examined. Treatment patterns and characteristics of patients potentially not managed well by acute/preventive treatment were described in migraine cohort.
Results
In the headache cohort, 989,514 patients were included with 57.0% females and mean age of 40.3 years; 77.0% patients visited clinics (with ≤ 19 bed capacities) for their primary diagnosis, and 30.3% patients underwent imaging tests (computed tomography and/or magnetic resonance imaging). In the migraine cohort, 165,339 patients were included with 65.0% females and mean age of 38.8 years. In the migraine cohort, 95.6% received acute treatment while 20.8% received preventive treatment. Acetaminophen/non-steroidal anti-inflammatory drugs were most common (54.8%) as the initial prescription for migraine treatment followed by triptan (51.4%). First treatment prescription included preventive treatment in 15.6%, while the proportion increased to 82.2% in the fourth treatment prescription. Among patients with more than 12 months of follow-up, 3.7% had prescription patterns suggestive of risk of medication-overuse headache, and these patients were characterized by a higher percentage of females and a higher prevalence of comorbidities.
Conclusions
This study revealed that approximately one-fifth of the patients with migraine visiting medical facilities use preventive drugs. The presence of potential patients at risk of medication-overuse headache and the role of clinics in migraine treatment were also described.
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