The relevance of migraine in the clinical spectrum of mitochondrial disorders

Energy metabolism disorders in migraine: triggers, pathways, and therapeutic repurposing

Many migraine triggers, such as stress, sleep deprivation, fatigue, strenuous exercise, and fasting, are potentially linked to disturbances in brain energy metabolism, mitochondrial function, and oxidative stress. Alongside efforts to avoid modifiable factors, prophylactic migraine treatments that target brain energy metabolism have garnered increasing attention. However, the current evidence supporting the use of energy-modulating drugs in migraine treatment guidelines remains weak. This narrative review explores the relationship between energy metabolism and cortical spreading depression susceptibility, metabolic alterations in migraine (including glucose and insulin metabolism, insulin resistance, lipid metabolism, and energy metabolism imaging markers), oxidative stress and antioxidant defenses, mitochondrial dysfunction, and the role of energy metabolism-targeted medications in migraine management. Nutrients may help improve mitochondrial function, thereby alleviating brain energy metabolism deficits and oxidative stress in migraine.

Sexual Dimorphism in Migraine. Focus on Mitochondria

PURPOSE OF REVIEW

Migraine prevalence in females is up to 3 times higher than in males and females show higher frequency, longer duration, and increased severity of headache attacks, but the reason for that difference is not known. This narrative review presents the main aspects of sex dimorphism in migraine prevalence and discusses the role of sex-related differences in mitochondrial homeostasis in that dimorphism. The gender dimension is also shortly addressed.

RECENT FINDINGS

The imbalance between energy production and demand in the brain susceptible to migraine is an important element of migraine pathogenesis. Mitochondria are the main energy source in the brain and mitochondrial impairment is reported in both migraine patients and animal models of human migraine. However, it is not known whether the observed changes are consequences of primary disturbance of mitochondrial homeostasis or are secondary to the migraine-affected hyperexcitable brain. Sex hormones regulate mitochondrial homeostasis, and several reports suggest that the female hormones may act protectively against mitochondrial impairment, contributing to more effective energy production in females, which may be utilized in the mechanisms responsible for migraine progression. Migraine is characterized by several comorbidities that are characterized by sex dimorphism in their prevalence and impairments in mitochondrial functions. Mitochondria may play a major role in sexual dimorphism in migraine through the involvement in energy production, the dependence on sex hormones, and the involvement in sex-dependent comorbidities. Studies on the role of mitochondria in sex dimorphism in migraine may contribute to precise personal therapeutic strategies.

1H-MRS reveals abnormal energy metabolism and excitatory-inhibitory imbalance in a chronic migraine-like state induced by nitroglycerin in mice

BACKGROUND

Chronic migraine is closely related to the dysregulation of neurochemical substances in the brain, with metabolic imbalance being one of the proposed causes of chronic migraine. This study aims to evaluate the metabolic changes between energy metabolism and excitatory and inhibitory neurotransmitters in key brain regions of mice with chronic migraine-like state and to uncover the dysfunctional pathways of migraine.

METHODS

A chronic migraine-like state mouse model was established by repeated administration of nitroglycerin (NTG). We used von Frey filaments to assess the mechanical thresholds of the hind paw and periorbital in wild-type and familial hemiplegic migraine type 2 mice. After the experiments, tissue was collected from five brain regions: the somatosensory cortex (SSP), hippocampus, thalamus (TH), hypothalamus, and the spinal trigeminal nucleus caudalis (TNC). Proton magnetic resonance spectroscopy (1H-MRS) was employed to study the changes in brain metabolites associated with migraine, aiming to explore the mechanisms underlying metabolic imbalance in chronic migraine-like state.

RESULTS

In NTG-induced chronic migraine-like state model, we observed a significant reduction in energy metabolism during central sensitization, an increase in excitatory neurotransmitters such as glutamate, and a tendency for inhibitory neurotransmitters like GABA to decrease. The TNC and thalamus were the most affected regions. Furthermore, the consistency of N-acetylaspartate levels highlighted the importance of the TNC-TH-SSP pathway in the ascending nociceptive transmission of migraine.

CONCLUSION

Abnormal energy metabolism and neurotransmitter imbalance in the brain region of NTG-induced chronic migraine-like state model are crucial mechanisms contributing to the chronicity of migraine.

Evidence for sodium valproate toxicity in mitochondrial diseases: a systematic analysis

Background

We aimed to determine whether sodium valproate (VPA) should be contraindicated in all mitochondrial diseases, due to known VPA-induced severe hepatotoxicity in some mitochondrial diseases.

Methods

We systematically reviewed the published literature for mitochondrial DNA (mtDNA) and common nuclear genotypes of mitochondrial diseases using PubMed, Ovid Embase, Ovid Medline and MitoPhen databases. We extracted patient-level data from peer-reviewed articles, published until July 2022, using the Human Phenotype Ontology to manually code clinical presentations for 156 patients with genetic diagnoses from 90 publications.

Results

There were no fatal adverse drug reactions (ADRs) in the mtDNA disease group (35 patients), and only 1 out of 54 patients with a non-POLG mitochondrial disease developed acute liver failure. There were fatal outcomes in 53/102 (52%) POLG VPA-exposed patients who all harboured recessive mutations.

Conclusions

Our findings confirm the high risk of severe ADRs in any patient with recessive POLG variants irrespective of the phenotype, and therefore recommend that VPA is contraindicated in this group. However, there was limited evidence of toxicity to support a similar recommendation in other genotypes of mitochondrial diseases.

[Migraine and mitochondrial diseases : Energy deficit in the brain]

Mitochondrial diseases are complex metabolic disorders caused by genetic mutations and lead to impaired energy production in the mitochondria of cells. The clinical spectrum ranges from severe multiorgan involvement in early childhood to mild monosymptomatic courses in adulthood. The brain, heart, and skeletal muscles are particularly affected due to their high energy demands. Headaches in general and migraine in particular, occur disproportionately more frequently in patients with mitochondrial diseases. In recent years similarities in the pathomechanism of mitochondrial diseases and migraine have been investigated in numerous biochemical, genetic, and therapeutic studies. The results suggest a dysfunctional energy metabolism with demonstrable mitochondrial damage as a central aspect in the pathogenesis of migraine. These findings are valuable for a better understanding of primary headache disorders and mitochondrial diseases as well as for the optimization of diagnostic and treatment procedures and should be applied in the clinical practice.

[Migraine and mitochondrial diseases : Energy deficit in the brain]

Mitochondrial diseases are complex metabolic disorders caused by genetic mutations and lead to impaired energy production in the mitochondria of cells. The clinical spectrum ranges from severe multiorgan involvement in early childhood to mild monosymptomatic courses in adulthood. The brain, heart, and skeletal muscles are particularly affected due to their high energy demands. Headaches in general and migraine in particular, occur disproportionately more frequently in patients with mitochondrial diseases. In recent years similarities in the pathomechanism of mitochondrial diseases and migraine have been investigated in numerous biochemical, genetic, and therapeutic studies. The results suggest a dysfunctional energy metabolism with demonstrable mitochondrial damage as a central aspect in the pathogenesis of migraine. These findings are valuable for a better understanding of primary headache disorders and mitochondrial diseases as well as for the optimization of diagnostic and treatment procedures and should be applied in the clinical practice.

Genetics of migraine: where are we now?

Migraine is a complex brain disorder explained by the interaction of genetic and environmental factors. In monogenic migraines, including familial hemiplegic migraine and migraine with aura associated with hereditary small-vessel disorders, the identified genes code for proteins expressed in neurons, glial cells, or vessels, all of which increase susceptibility to cortical spreading depression. The study of monogenic migraines has shown that the neurovascular unit plays a prominent role in migraine. Genome-wide association studies have identified numerous susceptibility variants that each result in only a small increase in overall migraine risk. The more than 180 known variants belong to several complex networks of "pro-migraine" molecular abnormalities, which are mainly neuronal or vascular. Genetics has also highlighted the importance of shared genetic factors between migraine and its major co-morbidities, including depression and high blood pressure. Further studies are still needed to map all of the susceptibility loci for migraine and then to understand how these genomic variants lead to migraine cell phenotypes.

Meta-analytical evidence of functional and structural abnormalities associated with pain processing in migraine patients: An activation likelihood estimation

BACKGROUND

Migraine is a primary headache disorder that causes debilitating throbbing pain. Several functional MRI (fMRI) and voxel-based morphometry (VBM) studies have been used to investigate the structural and functional alteration in migraine. Here, we aim to study the converged brain regions of functional and structural abnormalities in gray matter volume (GMV) associated with pain processing and management in migraineurs and healthy controls (HC).

METHODS

A systematic search through PubMed and Sleuth was carried out for peer-reviewed functional and structural neuroimaging studies on migraine patients and HC yielded a total of 1136 studies. We performed an activation likelihood estimation (ALE) meta-analysis on VBM and pain stimulation task-based fMRI studies to investigate the converged areas of GMV and functional abnormalities between migraineurs and HC. We performed two subgroup analyses between migraine with aura (MwA) and migraine without aura (MwoA) relative to HC, and between chronic migraine (CM) and episodic migraine (EM) compared to HC.

RESULTS

The total sample included 16 fMRI and 22 VBM studies, consisting of 1295 migraine patients, compared to 995 HC. In fMRI analysis, ALE maps for pain stimulation tasks revealed hyperactivation in migraineurs in the substantia nigra compared to HC, whereas hypoactivation was seen in the cerebellum. For the VBM analysis, ALE clusters of increased GMV in migraineurs were observed in the parahippocampus and putamen nucleus. Whereas clusters of reduced GMV in migraineurs were seen in the frontal gyri. Compared to HC, MwoA patients showed a GMV reduction in the insula, and anterior cingulate, whereas MwA patients showed GMV reduction in the cerebellum, cingulate gyrus, and insula. CM patients showed decreased GMV in the precentral gyrus, whereas EM patients showed decreased GMV in the parahippocampus, and inferior frontal gyrus when compared to HC.

CONCLUSIONS

Our findings represent a potential biomarker for the diagnosis and management of migraine, by showing clustered brain regions of abnormal patterns of activation and GMV changes between migraineurs and HC which might be associated with hyposensitivity to pain in migraineurs. Further studies are required to determine disease progression or therapeutic interventions' effect on migraine.

Alterations in metabolic flux in migraine and the translational relevance

BACKGROUND

Migraine is a highly prevalent disorder with significant economical and personal burden. Despite the development of effective therapeutics, the causes which precipitate migraine attacks remain elusive. Clinical studies have highlighted altered metabolic flux and mitochondrial function in patients. In vivo animal experiments can allude to the metabolic mechanisms which may underlie migraine susceptibility. Understanding the translational relevance of these studies are important to identifying triggers, biomarkers and therapeutic targets in migraine.

MAIN BODY

Functional imaging studies have suggested that migraineurs feature metabolic syndrome, exhibiting hallmark features including upregulated oxidative phosphorylation yet depleted available free energy. Glucose hypometabolism is also evident in migraine patients and can lead to altered neuronal hyperexcitability such as the incidence of cortical spreading depression (CSD). The association between obesity and increased risk, frequency and worse prognosis of migraine also highlights lipid dysregulation in migraine pathology. Calcitonin gene related peptide (CGRP) has demonstrated an important role in sensitisation and nociception in headache, however its role in metabolic regulation in connection with migraine has not been thoroughly explored. Whether impaired metabolic function leads to increased release of peptides such as CGRP or excessive nociception leads to altered flux is yet unknown.

CONCLUSION

Migraine susceptibility may be underpinned by impaired metabolism resulting in depleted energy stores and altered neuronal function. This review discusses both clinical and in vivo studies which provide evidence of altered metabolic flux which contribute toward pathophysiology. It also reviews the translational relevance of animal studies in identifying targets of biomarker or therapeutic development.

Magnetic resonance spectroscopy studies in migraine

This review summarizes major findings and recent advances in magnetic resonance spectroscopy (MRS) of migraine. A multi database search of PubMed, EMBASE, and Web of Science was performed with variations of magnetic resonance spectroscopy and headache until 20th September 2021. The search generated 2897 studies, 676 which were duplicates and 1836 were not related to headache. Of the remaining 385 studies examined, further exclusions for not migraine (n = 114), and not MRS of human brain (n = 128), and non-original contributions (n = 51) or conferences (n = 24) or case studies (n = 11) or non-English (n = 3), were applied. The manuscripts of all resulting reports were reviewed for their possible inclusion in this manuscript (n = 54). The reference lists of all included reports were carefully reviewed and articles relevant to this review were added (n = 2).Included are 56 studies of migraine with and without aura that involve magnetic resonance spectroscopy of the human brain. The topics are presented in the form of a narrative review. This review aims to provide a summary of the metabolic changes measured by MRS in patients with migraine. Despite the variability reported between studies, common findings focused on regions functionally relevant to migraine such as occipital cortices, thalamic nuclei, cerebellum and cingulate. The most reproducible results were decreased N-acetyl-aspartate (NAA) in cerebellum in patients with hemiplegic migraine and in the thalamus of chronic migraine patients. Increased lactate (Lac) in the occipital cortex was found for migraine with aura but not in subjects without aura. MRS studies support the hypothesis of impaired energetics and mitochondrial dysfunction in migraine. Although results regarding GABA and Glu were less consistent, studies suggest there might be an imbalance of these important inhibitory and excitatory neurotransmitters in the migraine brain. Multinuclear imaging studies in migraine with and without aura, predominantly investigating phosphorous, report alterations of PCr in occipital, parietal, and posterior brain regions. There have been too few studies to assess the diagnostic relevance of sodium imaging in migraine.