Spreading depression as a preclinical model of migraine

Non-invasive vagus nerve stimulation for primary headache: A clinical update

Background

Non-invasive vagus nerve stimulation (nVNS) is a proven treatment for cluster headache and migraine. Several possible mechanisms of action by which nVNS mitigates headache have been identified.

Methods

We conducted a narrative review of recent scientific and clinical research into nVNS for headache, including findings from mechanistic studies and their possible relationships to the clinical effects of nVNS.

Results

Findings from animal and human studies have provided possible mechanistic explanations for nVNS efficacy in headache involving four core areas: Autonomic nervous system functions; cortical spreading depression inhibition; neurotransmitter regulation; and nociceptive modulation. We discuss how overlap and interplay among these areas may underlie the utility of nVNS in the context of clinical evidence supporting its safety and efficacy as acute and preventive therapy for both cluster headache and migraine. Possible future nVNS applications are also discussed.

Conclusion

Significant progress over the past several years has yielded valuable mechanistic and clinical evidence that, combined with the excellent safety and tolerability profile of nVNS, suggests that it should be considered a first-line treatment for both acute and preventive treatment of cluster headache, an effective option for acute treatment of migraine, and a highly relevant, practical option for migraine prevention.

Therapeutic implications of cortical spreading depression models in migraine

Migraine is among the most common and disabling neurological diseases in the world. Cortical spreading depression (CSD) is a wave of near-complete depolarization of neurons and glial cells that slowly propagates along the cortex creating the perception of aura. Evidence suggests that CSD can trigger migraine headache. Experimental models of CSD have been considered highly translational as they recapitulate migraine-related phenomena and have been validated for screening migraine therapeutics. Here we outline the essential components of validated experimental models of CSD and provide a comprehensive review of potential modulators and targets against CSD. We further focus on novel interventions that have been recently shown to suppress CSD susceptibility that may lead to therapeutic targets in migraine.

Migraine and Ischemic Stroke: Deciphering the Bidirectional Pathway

Migraine and stroke are common, disabling neurological conditions with several theories being proposed to explain this bidirectional relationship. Migraine is considered as a benign neurological disorder, but research has revealed a connection between migraine and stroke, predominantly those having migraine with aura (MA). Among migraineurs, females with MA are more susceptible to ischemic stroke and may have a migrainous infarction. Migrainous infarction mostly occurs in the posterior circulation of young women. Although there are several theories about the potential relationship between MA and stroke, the precise pathological process of migrainous infarction is not clear. It is assumed that cortical spreading depression (CSD) might be one of the essential factors for migrainous infarction. Other factors that may contribute to migrainous infarction may be genetic, hormonal fluctuation, hypercoagulation, and right to left cardiac shunts. Antimigraine drugs, such as ergot alkaloids and triptans, are widely used in migraine care. Still, they have been found to cause severe vasoconstriction, which may result in the development of ischemia. It is reported that patients with stroke develop migraines during the recovery phase. Both experimental and clinical data suggest that cerebral microembolism can act as a potential trigger for MA. Further studies are warranted for the treatment of migraine, which may lead to a decline in migraine-related stroke. In this present article, we have outlined various potential pathways that link migraine and stroke.

Proposal for a new diagnosis for U.S. diplomats in Havana, Cuba, experiencing vestibular and neurological symptoms

Between 2016 and 2017, several U.S. Diplomats in Havana, Cuba, experienced perplexing vestibular and neurological symptoms attributed to an unknown source. They presented with significant vestibular and headache symptoms similar to individuals who experience vestibular migraine (VM). As such, we hypothesize that VM may be a possible explanation for the Havana cohort's presenting symptoms. To evaluate this hypothesis, we compared symptoms reported by the affected individuals in Havana, Cuba, to symptoms reported by corresponding patients from a tertiary academic neurotology clinic with a chief complaint of vertigo or disequilibrium, who met the International Classification of Headache Disorders criteria for VM. The prevalence of the Havana subjects experiencing various symptomatic domains was compared with the VM cohort, leading to 26 unique domains and statistical comparisons between the cohorts. Of the 26 domains compared between the two cohorts, 18 were not significantly different. This included the two most important components of meeting criteria for VM, namely the co-existence of headache and vestibular symptoms. On regression analysis, the only feature which kept its significant difference between the two cohorts was acute intense head pressure (P = 0.007). The domains with similar occurrence ratios included dizziness, headache, light sensitivity, hearing reduction, and tinnitus. In other words, multiple headache and vestibular symptoms, consistent with VM criteria, were similar between the two cohorts. The considerable similarities across various domains between VM patients and Havana subjects could be due to migraine as a possible common etiology for both groups. We propose VM as a potential etiology for the symptomatology in the U.S. diplomats in Cuba.

Efficacy of electrical stimulation for treatment of migraine

BACKGROUND

The objective of this study is to assess the efficacy of electrical stimulation (ES) for the treatment of patients with migraine.

METHODS

MEDLINE, EMBASE, Cochrane Library, CINAHL, PsycINFO, Scopus, Web of Science, Allied and Complementary Medicine Database, ProQuest Nursing and Allied Health, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure will be searched for eligible studies. All electronic databases will be searched from inception to the present with no language restriction. Two authors will independently carry out study selection, data collection, and study quality assessment, respectively. RevMan 5. 3 software will be used for statistical analysis.

RESULTS

This study will summarize high quality evidence on the efficacy and safety of ES for the treatment of migraine.

CONCLUSION

This study will establish the accurate results of ES for migraine to facilitate the clinical practice and guideline development.

PROSPERO REGISTRATION NUMBER

PROSPERO CRD42019147480.

A hypothetical proposal for association between migraine and Meniere's disease

Meniere's disease (MD) is a chronic condition affecting the inner ear whose precise etiology is currently unknown. We propose the hypothesis that MD is a migraine-related phenomenon which may have implications for future treatment options for both diseases. The association between MD and migraine is both an epidemiological and a mechanistic one, with up to 51% of individuals with MD experiencing migraine compared to 12% in the general population. The presence of endolymphatic hydrops in those with MD may be the factor that unites the two conditions, as hydropic inner ears have an impaired ability to maintain homeostasis. Migraine headaches are theorized to cause aura and symptoms via spreading cortical depression that ultimately results in substance P release, alterations in blood flow, and neurogenic inflammation. Chronically hydropic inner ears are less able to auto-regulate against the changes induced by active migraine attacks and may ultimately manifest as MD. This same vulnerability to derangements in homeostasis may also explain the common triggering factors of both MD attacks and migraine headaches, including stress, weather, and diet. Similarly, it may explain the efficacy of common treatments for both diseases: current migraine treatments such as anti-hypertensives and anti-convulsants have shown promise in managing MD. Though the etiology of both MD and migraine is likely multifactorial, further exploration of the association between the two conditions may illuminate how to best manage them in the future. MD is likely a manifestation of cochleovestibular migraine, which occurs as a result of migraine related changes in both the cochlea and vestibule.

Curcumin Protects Human Umbilical Vein Endothelial Cells against H2O2-Induced Cell Injury

Migraine is a prevalent neurological disorder which causes a huge economic burden on society. It is thought to be a neurovascular disease with oxidative stress might be involved. Curcumin, one of the major ingredients of turmeric, has potent antioxidative and anti-inflammatory properties, but whether it could be used as a potential treatment for migraine remains to be explored. In the present study, human umbilical vein endothelial cells (HUVECs) were pretreated with various concentrations of curcumin (0 μM, 10 μM, 20 μM, 30 μM, 40 μM, and 50 μM) for 12 h, thereby exposed to H₂O₂ (100 μM) for another 12 h. The viability of HUVECs was tested by the CCK-8 assay, and the activities of antioxidant enzymes including superoxide dismutase (SOD) and glutathione (GSH) were also examined. Intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) were assayed to determine H₂O₂-induced oxidative stress. In addition, several cell death-related genes (p53, p21, Bax, and Bcl-2) were detected by PCR, and an apoptosis-related protein (caspase3) was evaluated by western blotting. Our results showed that curcumin improved the H₂O₂-induced decrease of cell viability and antioxidative enzyme activities and decreased the level of oxidative stress. As a conclusion, curcumin could mitigate H₂O₂-induced oxidative stress and cell death in HUVECs and may be a potential therapeutic drug for migraine.