Assessing risk factors for migraine: differences in gender transmission

The TRPA1 Ion Channel Mediates Oxidative Stress-Related Migraine Pathogenesis

Although the introduction of drugs targeting calcitonin gene-related peptide (CGRP) revolutionized migraine treatment, still a substantial proportion of migraine patients do not respond satisfactorily to such a treatment, and new therapeutic targets are needed. Therefore, molecular studies on migraine pathogenesis are justified. Oxidative stress is implicated in migraine pathogenesis, as many migraine triggers are related to the production of reactive oxygen and nitrogen species (RONS). Migraine has been proposed as a superior mechanism of the brain to face oxidative stress resulting from energetic imbalance. However, the precise mechanism behind the link between migraine and oxidative stress is not known. Nociceptive primary afferent nerve fiber endings express ion channel receptors that change harmful stimuli into electric pain signals. Transient receptor potential cation channel subfamily A member 1 (TRPA1) is an ion channel that can be activated by oxidative stress products and stimulate the release of CGRP from nerve endings. It is a transmembrane protein with ankyrin repeats and conserved cysteines in its N-terminus embedded in the cytosol. TRPA1 may be a central element of the signaling pathway from oxidative stress and NO production to CGRP release, which may play a critical role in headache induction. In this narrative review, we present information on the role of oxidative stress in migraine pathogenesis and provide arguments that TRPA1 may be "a missing link" between oxidative stress and migraine and therefore a druggable target in this disease.

Risk of major mental disorders in the offspring of parents with migraine

BACKGROUND

Migraine has been associated with mental disorders, however whether parental migraine is associated with an increased risk of major mental disorders (MMDs) in offspring has not been investigated. We aimed to examine the risk of the development of MMDs in the offspring of parents with migraine compared with those of parents without migraine.

METHODS

This study used data derived from the Taiwan National Health Insurance Research Database. Offspring of parents with migraine and a control group consisting of offspring of parents without migraine matched for demographic and parental mental disorders were included. Cox regression was used to estimate the risk of MMDs, including schizophrenia, depressive disorder, bipolar disorder, autistic spectrum disorder (ASD), and attention deficit/hyperactivity disorder (ADHD). Sub-analyses stratified by the fathers and mothers were further performed to separately clarify the risks of MMDs among the offspring.

RESULTS

We included 22,747 offspring of parents with migraine and 227,470 offspring of parents without migraine as the controls. Parental migraine was significantly associated with an increased risk of ADHD (reported as hazard ratios with 95% confidence intervals: 1.37, 1.25-1.50), bipolar disorder (1.35, 1.06-1.71), and depressive disorder (1.33, 1.21-1.47) compared to the offspring of parents without migraine. Importantly, sub-analyses showed that only maternal migraine was significantly associated with these risks.

CONCLUSIONS

Due to the heavy burden of MMDs, healthcare workers should be aware of the risk of MMDs in the offspring of parents with migraine, particular in mothers.

CURRENT PERSPECTIVES ON MITOCHONDRIAL DYSFUNCTION IN MIGRAINE

Mitochondria is an autonomous organelle that plays a crucial role in the metabolic aspects of a cell. Cortical Spreading Depression (CSD) and fluctuations in the cerebral blood flow have for long been mechanisms underlying migraine. It is a neurovascular disorder with a unilateral manifestation of disturbing, throbbing and pulsating head pain. Migraine affects 2.6 and 21.7% of the general population and is the major cause of partial disability in the age group 15-49. Higher mutation rates, imbalance in concentration of physiologically relevant molecules, oxidative stress biomarkers have been the main themes of discussion in determining the role of mitochondrial disability in migraine. The correlation of migraine with other disorders like hemiplegic migraine, MELAS, TTH, CVS, ischemic stroke and hypertension has helped in the assessment of the physiological and morphogenetic basis of migraine. Here, we have reviewed the different nuances of mitochondrial dysfunction and migraine. The different mtDNA polymorphisms that can affect the generation and transmission of nerve impulse has been highlighted and supported with research findings. In addition to this, the genetic basis of migraine pathogenesis as a consequence of mutations in nuclear DNA that can in turn affect the synthesis of defective mitochondrial proteins is discussed along with a brief overview of epigenetic profile. This review gives an overview of the pathophysiology of migraine and explores mitochondrial dysfunction as a potential underlying mechanism. Also, therapeutic supplements for managing migraine have been discussed at different junctures in this paper.

The relevance of migraine in the clinical spectrum of mitochondrial disorders

Recent scientific evidence suggests a link between migraine and brain energy metabolism. In fact, migraine is frequently observed in mitochondrial disorders. We studied 46 patients affected by mitochondrial disorders, through a headache-focused semi-structured interview, to evaluate the prevalence of migraine among patients affected by mitochondrial disorders, the possible correlations between migraine and neuromuscular genotype or phenotype, comorbidities, lactate acid levels and brain magnetic resonance spectroscopy. We explored migraine-related disability, analgesic and prophylactic treatments. Diagnoses were achieved according to International Classification of Headache Disorders, 3rd edition. Lifetime prevalence of migraine was 61% (28/46), with high values in both sexes (68% in females, 52% in males) and higher than the values found in both the general population and previous literature. A maternal inheritance pattern was reported in 57% of cases. MIDAS and HIT6 scores revealed a mild migraine-related disability. The high prevalence of migraine across different neuromuscular phenotypes and genotypes suggests that migraine itself may be a common clinical manifestation of brain energy dysfunction. Our results provide new relevant indications in favour of migraine as the result of brain energy unbalance.

Migraine and neuroinflammation: the inflammasome perspective

BACKGROUND

Neuroinflammation has an important role in the pathophysiology of migraine, which is a complex neuro-glio-vascular disorder. The main aim of this review is to highlight findings of cortical spreading depolarization (CSD)-induced neuroinflammatory signaling in brain parenchyma from the inflammasome perspective. In addition, we discuss the limited data of the contribution of inflammasomes to other aspects of migraine pathophysiology, foremost the activation of the trigeminovascular system and thereby the generation of migraine pain.

MAIN BODY

Inflammasomes are signaling multiprotein complexes and key components of the innate immune system. Their activation causes the production of inflammatory cytokines that can stimulate trigeminal neurons and are thus relevant to the generation of migraine pain. The contribution of inflammasome activation to pain signaling has attracted considerable attention in recent years. Nucleotide-binding domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) is the best characterized inflammasome and there is emerging evidence of its role in a variety of inflammatory pain conditions, including migraine. In this review, we discuss, from an inflammasome point of view, cortical spreading depolarization (CSD)-induced neuroinflammatory signaling in brain parenchyma, the connection with genetic factors that make the brain vulnerable to CSD, and the relation of the inflammasome with diseases that are co-morbid with migraine, including stroke, epilepsy, and the possible links with COVID-19 infection.

CONCLUSION

Neuroinflammatory pathways, specifically those involving inflammasome proteins, seem promising candidates as treatment targets, and perhaps even biomarkers, in migraine.

Dietary magnesium and migraine in adults: A cross-sectional analysis of the National Health and Nutrition Examination Survey 2001-2004

BACKGROUND

Clinical trials have demonstrated magnesium supplements to be effective for prophylactic treatment of migraine. Dietary magnesium intake of many Americans is known to be below nutritional recommendations, but typical magnesium intake from dietary sources in adults with migraine has not previously been evaluated.

OBJECTIVE

This study aimed to quantify dietary and total (diet + supplement) magnesium consumption of adults with migraine or severe headache in the United States, and to investigate the relationship between magnesium consumption levels and prevalence of migraine or severe headache.

METHODS

This analysis included cross-sectional data from 3626 participants, 20- to 50-years old in the National Health and Nutrition Examination Survey between 2001 and 2004. Presence of migraine or severe headache in the past 3 months was determined by questionnaire. Individuals responding affirmatively were classified as having migraine, and individuals reporting not experiencing migraine or severe headache were classified as controls. Dietary magnesium intake was determined from a 24-hour recall interview, supplemental magnesium intake was determined from the dietary supplements interview, and total magnesium intake was the sum of dietary and supplement intake.

RESULTS

Mean dietary consumption of magnesium was below the recommended dietary allowance (RDA) for both migraine (n = 905) and control groups (n = 2721). Attainment of the RDA through a combination of diet and supplements was associated with lower adjusted odds of migraine (odds ratio [OR] = 0.83, 95% confidence intervals [CIs] = 0.70, 0.99, p = 0.035). Magnesium consumption in the highest quartile (Q) was associated with lower odds of migraine than in the lowest Q for both dietary (OR = 0.76, 95% CI = 0.63, 0.92, p = 0.006) and total (OR = 0.78, 95% CI = 0.62, 0.99, p = 0.042) magnesium intake in adjusted models.

CONCLUSION

These results suggest inadequate consumption of magnesium intake is associated with migraine in U.S. adults ages 20-50. Further prospective investigations are warranted to evaluate the role of dietary magnesium intake on migraine.

Going Deep into Synaptic Vesicle Machinery Genes and Migraine Susceptibility - A Case-Control Association Study

OBJECTIVE

A number of observations, including among our study population, have implicated variants in the syntaxin-1A, a component of the synaptic vesicles, in migraine susceptibility. Therefore, we hypothesize that variants in other components of the vesicle machinery are involved in migraine.

BACKGROUND

Migraine is a common and complex neurologic disorder that affects approximately 15-18% of the general population. The exact cause of migraine is unknown; however, genetic studies have made possible substantial progress toward the identification of underlying molecular pathways. Neurotransmitters have been for long considered to have a key role in migraine pathophysiology; so we investigated common variants in genes involved in the synaptic vesicle machinery and their impact in migraine susceptibility.

METHODS

We performed a case-control study comprising 188 unrelated patients with headache and 286 healthy controls in a population from the north of Portugal. Benefiting from the presence of linkage disequilibrium, we selected and genotyped 119 tagging single-nucleotide polymorphisms in 18 genes.

RESULTS

We found significant associations between single-nucleotide variants and migraine in 7 genes, SYN1, SYN2, SNAP25, VAMP2, STXBP1, STXBP5, and UNC13A, either conferring an increased risk or protection of migraine. Due to SYN1 X-chromosomal location, we performed the statistical analysis separated by gender and, in the female group, the C allele of rs5906435 increased the risk for migraine susceptibility (P = .021; OR = 1.69; 95% CI: 1.21-2.34). In contrast, the TT genotype of the same variant emerged as a potential protective factor (P = .003; OR = 0.45; 95% CI: 0.27-0.74). The SYN2 analysis supported the rs3773364's G allele (P = .014) as a risk factor for migraine, and although not statistically significant after correction, the AG genotype (P = .006; OR = 1.86; 95% CI: 1.20-2.90) reinforced the allelic findings. Additionally, we found the SNAP25-rs363039's CT genotype (P = .001; OR = 2.14; 95% CI: 1.36-3.34), the STXBP5-rs1765028's T allele (P = .041; OR = 1.46; 95% CI: 1.13-1.90), and the UNC13B-rs7851161's TT genotype (P = .001; OR = 2.14; 95% CI: 1.36-3.34) as statistically significant risk factors for migraine liability. VAMP2-rs1150's G allele revealed a risk association to migraine, not statistically significant after correction (P = .068). Additionally, we found haplotypes in SYN1, SYN2, STXBP1, and UNC13B to be associated with migraine.

CONCLUSIONS

Overall, this study provides a new insight into migraine liability, identifying possible starting points for functional studies.

Potential Protective Mechanisms of Ketone Bodies in Migraine Prevention

An increasing amount of evidence suggests that migraines are a response to a cerebral energy deficiency or oxidative stress levels that exceed antioxidant capacity. The ketogenic diet (KD), a diet mimicking fasting that leads to the elevation of ketone bodies (KBs), is a therapeutic intervention targeting cerebral metabolism that has recently shown great promise in the prevention of migraines. KBs are an alternative fuel source for the brain, and are thus likely able to circumvent some of the abnormalities in glucose metabolism and transport found in migraines. Recent research has shown that KBs-D-β-hydroxybutyrate in particular-are more than metabolites. As signalling molecules, they have the potential to positively influence other pathways commonly believed to be part of migraine pathophysiology, namely: mitochondrial functioning, oxidative stress, cerebral excitability, inflammation and the gut microbiome. This review will describe the mechanisms by which the presence of KBs, D-BHB in particular, could influence those migraine pathophysiological mechanisms. To this end, common abnormalities in migraines are summarised with a particular focus on clinical data, including phenotypic, biochemical, genetic and therapeutic studies. Experimental animal data will be discussed to elaborate on the potential therapeutic mechanisms of elevated KBs in migraine pathophysiology, with a particular focus on the actions of D-BHB. In complex diseases such as migraines, a therapy that can target multiple possible pathogenic pathways seems advantageous. Further research is needed to establish whether the absence/restriction of dietary carbohydrates, the presence of KBs, or both, are of primary importance for the migraine protective effects of the KD.

Parental migraine in relation to migraine in offspring: Family linkage analyses from the HUNT Study

Background

Migraine is known to run in families. While some clinical studies have indicated that migraine is disproportionally transmitted through the maternal line, this has not been examined in a population-based setting.

Methods

We utilized a large, population-based cohort study from Norway, the HUNT Study. Using a cross-sectional design, our sample consisted of 13,731 parents and 8970 offspring. Logistic regression was used to calculate odds ratios with 95% confidence intervals for active migraine and non-migrainous headache in offspring, given active maternal or paternal headache.

Results

There was a significant association between maternal migraine and offspring migraine (odds ratio 2.76, 95% confidence interval 2.18–3.51). A weaker association ( p = 0.004 for comparison with maternal migraine) was found between paternal migraine and offspring migraine (odds ratio 1.67, 95% confidence interval 1.33–2.28). For non-migrainous headache, there was a significant association between mothers and offspring (odds ratio 1.25, 95% confidence interval 1.10–1.43), but not between fathers and offspring.

Conclusions

Parental migraine is associated with offspring migraine, with a stronger association for maternal migraine. This may indicate maternal-specific transmission.

Sex differences in the epidemiology, clinical features, and pathophysiology of migraine

Migraine is two to three times more prevalent in women than men, and women report a longer attack duration, increased risk of headache recurrence, greater disability, and a longer period of time required to recover. Conditions recognised to be comorbid with migraine include asthma, anxiety, depression, and other chronic pain conditions, and these comorbidities add to the amount of disability in both sexes. Migraine-specifically migraine with aura-has been identified as a risk factor for vascular disorders, particularly in women, but because of the scarcity of data, the comparative risk in men has yet to be established. There is evidence implicating the role of female sex hormones as a major factor in determining migraine risk and characteristics, which accounts for sex differences, but there is also evidence to support underlying genetic variance. Although migraine is often recognised in women, it is underdiagnosed in men, resulting in suboptimal management and less participation of men in clinical trials.

Migraine genetics: current findings and future lines of research

In the last two decades, migraine research has greatly advanced our current knowledge of the genetic contributions and the pathophysiology of this common and debilitating disorder. Nonetheless, this knowledge still needs to grow further and to translate into more effective treatments. To date, several genes involved in syndromic and monogenic forms of migraine have been identified, allowing the generation of animal models which have significantly contributed to current knowledge of the mechanisms underlying these rare forms of migraine. Common forms of migraine are instead posing a greater challenge, as they may most often stem from complex interactions between multiple common genetic variants, with environmental triggers. This paper reviews our current understanding of migraine genetics, moving from syndromic and monogenic forms to oligogenic/polygenic migraines most recently addressed with some success through genome-wide association studies. Methodological issues in study design and future perspectives opened by biomarker research will also be briefly addressed.

Interaction between γ-aminobutyric acid A receptor genes: new evidence in migraine susceptibility

Migraine is a common neurological episodic disorder with a female-to-male prevalence 3- to 4-fold higher, suggesting a possible X-linked genetic component. Our aims were to assess the role of common variants of gamma-aminobutyric acid A receptor (GABA_AR) genes, located in the X-chromosome, in migraine susceptibility and the possible interaction between them. An association study with 188 unrelated cases and 286 migraine-free controls age- and ethnic matched was performed. Twenty-three tagging SNPs were selected in three genes (GABRE, GABRA3 and GABRQ). Allelic, genotypic and haplotypic frequencies were compared between cases and controls. We also focused on gene-gene interactions. The AT genotype of rs3810651 of GABRQ gene was associated with an increased risk for migraine (OR: 4.07; 95% CI: 1.71-9.73, p=0.002), while the CT genotype of rs3902802 (OR: 0.41; 95% CI: 0.21-0.78, p=0.006) and GA genotype of rs2131190 of GABRA3 gene (OR: 0.53; 95% CI: 0.32-0.88, p=0.013) seem to be protective factors. All associations were found in the female group and maintained significance after Bonferroni correction. We also found three nominal associations in the allelic analyses although there were no significant results in the haplotypic analyses. Strikingly, we found strong interactions between six SNPs encoding for different subunits of GABA_AR, all significant after permutation correction. To our knowledge, we show for the first time, the putative involvement of polymorphisms in GABA_AR genes in migraine susceptibility and more importantly we unraveled a role for novel gene-gene interactions opening new perspectives for the development of more effective treatments.

Mitochondrial dysfunction in migraine

Migraine is the most frequent type of headache in children. In the 1980s, scientists first hypothesized a connection between migraine and mitochondrial (mt) disorders. More recent studies have suggested that at least some subtypes of migraine may be related to a mt defect. Different types of evidence support a relationship between mitochondria (mt) and migraine: (1) Biochemical evidence: Abnormal mt function translates into high intracellular penetration of Ca(2+), excessive production of free radicals, and deficient oxidative phosphorylation, which ultimately causes energy failure in neurons and astrocytes, thus triggering migraine mechanisms, including spreading depression. The mt markers of these events are low activity of superoxide dismutase, activation of cytochrome-c oxidase and nitric oxide, high levels of lactate and pyruvate, and low ratios of phosphocreatine-inorganic phosphate and N-acetylaspartate-choline. (2) Morphologic evidence: mt abnormalities have been shown in migraine sufferers, the most characteristic ones being direct observation in muscle biopsy of ragged red and cytochrome-c oxidase-negative fibers, accumulation of subsarcolemmal mt, and demonstration of giant mt with paracrystalline inclusions. (3) Genetic evidence: Recent studies have identified specific mutations responsible for migraine susceptibility. However, the investigation of the mtDNA mutations found in classic mt disorders (mt encephalomyopathy with lactic acidosis and stroke-like episodes, myoclonus epilepsy with ragged red fibers, Kearns-Sayre syndrome, and Leber hereditary optic neuropathy) has not demonstrated any association. Recently, 2 common mtDNA polymorphisms (16519C→T and 3010G→A) have been associated with pediatric cyclic vomiting syndrome and migraine. Also, POLG mutations (eg, p.T851 A, p.N468D, p.Y831C, p.G517V, and p.P163S) can cause disease through impaired replication of mtDNA, including migraine. Further studies to investigate the relationship between mtDNA and migraine will require very large sample sizes to obtain statistically significant results. (4) Therapeutic evidence: Several agents that have a positive effect on mt metabolism have shown to be effective in the treatment of migraines. The agents include riboflavin (B2), coenzyme Q10, magnesium, niacin, carnitine, topiramate, and lipoic acid. Further study is warranted to learn how mt interact with other factors to cause migraines. This will facilitate the development of new and more specific treatments that will reduce the frequency or severity or both of this disease.