Cortical metabolic and structural differences in patients with chronic migraine. An exploratory 18FDG-PET and MRI study

Mediterranean ketogenic diet accounts for reduced pain frequency and intensity in patients with chronic migraine: A pilot study

BACKGROUND

An increasing amount of evidence suggests that migraine is a response to cerebral energy deficiencies or oxidative stress levels that exceed antioxidant capacity. Current pharmacological options are inadequate in treating patients with chronic migraine, and a growing interest focuses on nutritional approaches as non-pharmacological treatments. The ketogenic diet, mimicking fasting that leads to an elevation of ketone bodies, is a therapeutic intervention targeting cerebral metabolism that has recently shown great promise in the prevention of migraines. Moreover, Mediterranean elements like vegetables, nuts, herbs, spices, and olive oil that are sources of anti-inflammatory elements (omega-3 fatty acids, polyphenols, vitamins, essential minerals, and probiotics) may create a positive brain environment by reducing imbalance in the gut microbiome.

METHODS

On the basis of these indications, a combined Mediterranean-ketogenic diet was administered to chronic migraine patients for 4 (T1) and 8 weeks (T2), and anthropometric estimations were collected at T1 and T2 while biochemical parameters at only T2.

RESULTS

A significant reduction (p < 0.01) in migraine frequency and intensity was detected as early as 4 weeks of dietary intervention, which was associated with a reduced fat mass (p < 0.001) as well as Homa index (p < 0.05) and insulin levels (p < 0.01) after 8 weeks.

CONCLUSION

Overall, Mediterranean-ketogenic diet may be considered an effective non-pharmacological intervention for migraine, with positive outcomes on body composition.

Mind the Metabolic Gap: Bridging Migraine and Alzheimer's disease through Brain Insulin Resistance

Brain insulin resistance has recently been described as a metabolic abnormality of brain glucose homeostasis that has been proven to downregulate insulin receptors, both in astrocytes and neurons, triggering a reduction in glucose uptake and glycogen synthesis. This condition may generate a mismatch between brain's energy reserve and expenditure, ??mainly during high metabolic demand, which could be involved in the chronification of migraine and, in the long run, at least in certain subsets of patients, in the prodromic phase of Alzheimer's disease, along a putative metabolic physiopathological continuum. Indeed, the persistent disruption of glucose homeostasis and energy supply to neurons may eventually impair protein folding, an energy-requiring process, promoting pathological changes in Alzheimer's disease, such as amyloid-β deposition and tau hyperphosphorylation. Hopefully, the "neuroenergetic hypothesis" presented herein will provide further insight on there being a conceivable metabolic bridge between chronic migraine and Alzheimer's disease, elucidating novel potential targets for the prophylactic treatment of both diseases.

Influences of Genetic and Environmental Factors on Chronic Migraine: A Narrative Review

PURPOSE OF REVIEW

In this narrative review, we aim to summarize recent insights into the complex interplay between environmental and genetic factors affecting the etiology, development, and progression of chronic migraine (CM).

RECENT FINDINGS

Environmental factors such as stress, sleep dysfunction, fasting, hormonal changes, weather patterns, dietary compounds, and sensory stimuli are critical triggers that can contribute to the evolution of episodic migraine into CM. These triggers are particularly influential in genetically predisposed individuals. Concurrently, genome-wide association studies (GWAS) have revealed over 100 genetic loci linked to migraine, emphasizing a significant genetic basis for migraine susceptibility. In CM, environmental and genetic factors are of equal importance and contribute to the pathophysiology of the condition. Understanding the bidirectional interactions between these elements is crucial for advancing therapeutic approaches and preventive strategies. This balanced perspective encourages continued research into the complex gene-environment nexus to improve our understanding and management of CM.

Brain connectome-based imaging markers for identifiable signature of migraine with and without aura

Background

Cortical spreading depression (CSD) has been considered the prominent theory for migraine with aura (MwA). However, it is also argued that CSD can exist in patients in a silent state, and not manifest as aura. Thus, the MwA classification based on aura may be questionable. This study aimed to capture whole-brain connectome-based imaging markers with identifiable signatures for MwA and migraine without aura (MwoA).

Methods

A total of 88 migraine patients (32 MwA) and 49 healthy controls (HC) underwent a diffusion tensor imaging and resting-state functional magnetic resonance imaging scan. The whole-brain structural connectivity (SC) and functional connectivity (FC) analysis was employed to extract imaging features. The extracted features were subjected to an all-relevant feature selection process within cross-validation loops to pinpoint attributes demonstrating substantial efficacy for patient categorization. Based on the identified features, the predictive ability of the random forest classifiers constructed with the 88 migraine patients' sample was tested using an independent sample of 32 migraine patients (eight MwA).

Results

Compared to MwoA and HC, MwA showed two reduced SC and six FC (five increased and one reduced) features [all P<0.01, after false discovery rate (FDR) correction], involving frontal areas, temporal areas, visual areas, amygdala, and thalamus. A total of four imaging features were significantly correlated with clinical rating scales in all patients (r=-0.38 to 0.47, P<0.01, after FDR correction). The predictive ability of the random forest classifiers achieved an accuracy of 78.1% in the external sample to identify MwA.

Conclusions

The whole-brain connectivity features in our results may serve as connectome-based imaging markers for MwA identification. The alterations of SC and FC strength provide possible evidence in further understanding the heterogeneity and mechanism of MwA which may help for patient-specific decision-making.

Radiotracers in the Diagnosis of Pain: A Mini Review

The diagnosis and understanding of pain is challenging in clinical practice. Assessing pain relies heavily on self-reporting by patients, rendering it inherently subjective. Traditional clinical imaging methods such as computed tomography and magnetic resonance imaging can only detect anatomical abnormalities, offering limited sensitivity and specificity in identifying pain-causing conditions. Radiotracers play a vital role in molecular imaging that aims to identify abnormal biological processes at the cellular level, even in apparently normal anatomical structures. Therefore, molecular imaging is an important area of research as a prospective diagnostic modality for pain-causing pathophysiology. We present a mini review of the current knowledge base regarding radiotracers for identification of pain in vivo. We also describe radiocaine, a novel positron emission tomography imaging agent for sodium channels that has shown great potential for identifying/labeling pain-producing nerves and producing an objectively measurable pain intensity signal.

Peripherally acting anti-CGRP monoclonal antibodies alter cortical gray matter thickness in migraine patients: A prospective cohort study

Migraine is underpinned by central nervous system neuroplastic alterations thought to be caused by the repetitive peripheral afferent barrage the brain receives during the headache phase (cortical hyperexcitability). Calcitonin gene-related peptide monoclonal antibodies (anti-CGRP-mAbs) are highly effective migraine preventative treatments. Their ability to alter brain morphometry in treatment-responders vs. non-responders is not well understood. Our aim was to determine the effects of the anti-CGRP-mAb galcanezumab on cortical thickness after 3-month treatment of patients with high-frequency episodic or chronic migraine. High-resolution magnetic resonance imaging was performed pre- and post-treatment in 36 migraine patients. In this group, 19 patients were classified responders (≥50 % reduction in monthly migraine days) and 17 were considered non-responders (<50 % reduction in monthly migraine days). Following cross-sectional processing to analyze the baseline differences in cortical thickness, two-stage longitudinal processing and symmetrized percent change were conducted to investigate treatment-related brain changes. At baseline, no significant differences were found between the responders and non-responders. After 3-month treatment, decreased cortical thickness (compared to baseline) was observed in the responders in regions of the somatosensory cortex, anterior cingulate cortex, medial frontal cortex, superior frontal gyrus, and supramarginal gyrus. Non-responders demonstrated decreased cortical thickness in the left dorsomedial cortex and superior frontal gyrus. We interpret the cortical thinning seen in the responder group as suggesting that reduction in head pain could lead to changes in neural swelling and dendritic complexity and that such changes reflect the recovery process from maladaptive neural activity. This conclusion is further supported by our recent study showing that 3 months after treatment initiation, the incidence of premonitory symptoms and prodromes that are followed by headache decreases but not the incidence of the premonitory symptoms or prodromes themselves (that is, cortical thinning relates to reductions in the nociceptive signals in the responders). We speculate that a much longer recovery period is required to allow the brain to return to a more 'normal' functioning state whereby prodromes and premonitory symptoms no longer occur.

Imaging Correlates between Headache and Breast Cancer: An [18F]FDG PET Study

This study aimed to examine brain metabolic patterns on [18F]Fluorodeoxyglucose ([18F]FDG) positron emission tomography (PET) in breast cancer (BC), comparing patients with tension-type headache (TTH), migraine (MiG), and those without headache. Further association with BC response to neoadjuvant chemotherapy (NAC) was explored. In this prospective study, BC patients eligible for NAC performed total-body [18F]FDG PET/CT with a dedicated brain scan. A voxel-wise analysis (two-sample t-test) and a multiple regression model were used to compare brain metabolic patterns among TTH, MiG, and no-headache patients and to correlate them with clinical covariates. A single-subject analysis compared each patient's brain uptake before and after NAC with a healthy control group. Primary headache was diagnosed in 39/46 of BC patients (39% TTH and 46% MiG). TTH patients exhibited hypometabolism in specific brain regions before NAC. TTH patients with a pathological complete response (pCR) to NAC showed hypermetabolic brain regions in the anterior medial frontal cortex. The correlation between tumor uptake and brain metabolism varied before and after NAC, suggesting an inverse relationship. Additionally, the single-subject analysis revealed that hypometabolic brain regions were not present after NAC. Primary headache, especially MiG, was associated with a better response to NAC. These findings suggest complex interactions between BC, headache, and hormonal status, warranting further investigation in larger prospective cohorts.

Modifiable factors for migraine prophylaxis: A mendelian randomization analysis

Objective: To examine the causal effect of potentially modifiable risk factors contributing to migraine pathogenesis. Methods: We performed Mendelian randomization analyses and acquired data from United Kingdom Biobank, FinnGen Biobank, and the MRC IEU OpenGWAS data infrastructure. An inverse-variance weighted (IVW) model was used to examine the relationship between 51 potentially modifiable risk factors and migraine in 3215 participants with migraine without aura (MwoA), 3541 participants with migraine with aura (MwA), and 176,107 controls. We adopted a Bonferroni-corrected threshold of p = 9.8 × 10-4 (.05 divided by 51 exposures) as a sign of significant effect, and a p < .05 was considered as the sign of a suggestive association. Results: More years of schooling significantly correlated with lower odds of MwoA pathogenesis (OR .57 [95%CI .44 to .75], p < .0001). More vitamin B12 intake (OR .49 [95%CI .24 to .99], p = .046) and lower level of stress [OR 8.17 (95%CI 1.5 to 44.36), p = .015] or anxiety disorder (OR 1.92 × 109 [95%CI 8.76 to 4.23*1017], p = .029) were suggestive to be correlated lower odds of MwoA pathogenesis. More coffee intake (OR .39 [95%CI .22 to .7], p = .001), lower level of eicosapentaenoic acid status (OR 2.54 [95%CI 1.03 to 6.26], p = .043), and more light physical activity (OR .09 [95%CI .01 to .94], p = .046) were suggestive to be associated with lower odds of MwA. Conclusion: The years of schooling, light physical activity, vitamin B12 intake, and coffee intake were the protective factors for migraine; stress, anxiety, and eicosapentaenoic acid status were harmful factors. Interventions could be developed based on modifying these factors for migraine prophylaxis.

Association between brain structures and migraine: A bidirectional Mendelian randomization study

Background

Accumulating evidence of clinical and neuroimaging studies indicated that migraine is related to brain structural alterations. However, it is still not clear whether the associations of brain structural alterations with migraine are likely to be causal, or could be explained by reverse causality confounding.

Methods

We carried on a bidirectional Mendelian randomization analysis in order to identify the causal relationship between brain structures and migraine risk. Summary-level data and independent variants used as instruments came from large genome-wide association studies of total surface area and average thickness of cortex (33,992 participants), gray matter volume (8,428 participants), white matter hyperintensities (50,970 participants), hippocampal volume (33,536 participants), and migraine (102,084 cases and 771,257 controls).

Results

We identified suggestive associations of the decreased surface area (OR = 0.85; 95% CI, 0.75-0.96; P = 0.007), and decreased hippocampal volume (OR = 0.74; 95% CI, 0.55-1.00; P = 0.047) with higher migraine risk. We did not find any significant association of gray matter volume, cortical thickness, or white matter hyperintensities with migraine. No evidence supporting the significant association was found in the reverse MR analysis.

Conclusion

We provided suggestive evidence that surface area and hippocampal volume are causally associated with migraine risk.

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.

Behavioral and psychological factors in individuals with migraine without psychiatric comorbidities

BACKGROUND

It is well known that the course of migraine is influenced by comorbidities and that individual psychological characteristics may impact on the disease. Proper identification of psychological factors that are relevant to migraine is important to improve non-pharmacological management. This study aimed at investigating the relationship between psychological factors and migraine in subjects free of psychiatric comorbidities.

METHODS

A sample of women with episodic (EM) and chronic migraine (CM) without history of psychiatric comorbidities were included in this cross-sectional study. The study also included female healthy controls (HC) without migraine or other primary headaches. We evaluated sleep, anxiety, depression, intolerance of uncertainty, decision making style and tendence to pain catastrophizing by validated self-report questionnaires or scales. Comparisons among groups were performed using ANOVA and Bonferroni post-hoc tests. Statistical significance was set at p < 0.05.

RESULTS

A total of 65 women with EM (mean age ± SD, 43.9 ± 7.2), 65 women with CM (47.7 ± 8.5), and 65 HC (43.5 ± 9.0) were evaluated. In sleep domains, CM patients reported poorer overall sleep quality, more severe sleep disturbances, greater sleep medication use, higher daytime dysfunction, and more severe insomnia symptoms than HC. EM group showed better sleep quality, lower sleep disturbances and sleep medication use than CM. On the other hand, the analysis highlighted more severe daytime dysfunction and insomnia symptoms in EM patients compared to HC. In anxiety and mood domains, CM showed greater trait anxiety and a higher level of general anxiety sensitivity than HC. Specifically, CM participants were more afraid of somatic and cognitive anxiety symptoms than HC. No difference in depression severity emerged. Finally, CM reported a higher pain catastrophizing tendency, more severe feeling of helplessness, and more substantial ruminative thinking than EM and HC, whilst EM participants reported higher scores in the three above-mentioned dimensions than HC. The three groups showed similar decision-making styles, intolerance of uncertainty, and strategies for coping with uncertainty.

CONCLUSIONS

Even in individuals without psychiatric comorbidities, specific behavioral and psychological factors are associated with migraine, especially in its chronic form. Proper identification of those factors is important to improve management of migraine through non-pharmacological strategies.

Headache-related circuits and high frequencies evaluated by EEG, MRI, PET as potential biomarkers to differentiate chronic and episodic migraine: Evidence from a systematic review

Background

The diagnosis of migraine is mainly clinical and self-reported, which makes additional examinations unnecessary in most cases. Migraine can be subtyped into chronic (CM) and episodic (EM). Despite the very high prevalence of migraine, there are no evidence-based guidelines for differentiating between these subtypes other than the number of days of migraine headache per month. Thus, we consider it timely to perform a systematic review to search for physiological evidence from functional activity (as opposed to anatomical structure) for the differentiation between CM and EM, as well as potential functional biomarkers. For this purpose, Web of Science (WoS), Scopus, and PubMed databases were screened.

Findings

Among the 24 studies included in this review, most of them (22) reported statistically significant differences between the groups of CM and EM. This finding is consistent regardless of brain activity acquisition modality, ictal stage, and recording condition for a wide variety of analyses. That speaks for a supramodal and domain-general differences between CM and EM that goes beyond a differentiation based on the days of migraine per month. Together, the reviewed studies demonstrates that electro- and magneto-physiological brain activity (M/EEG), as well as neurovascular and metabolic recordings from functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), show characteristic patterns that allow to differentiate between CM and EM groups.

Conclusions

Although a clear brain activity-based biomarker has not yet been identified to distinguish these subtypes of migraine, research is approaching headache specialists to a migraine diagnosis based not only on symptoms and signs reported by patients. Future studies based on M/EEG should pay special attention to the brain activity in medium and fast frequency bands, mainly the beta band. On the other hand, fMRI and PET studies should focus on neural circuits and regions related to pain and emotional processing.

A preliminary trial of botulinum toxin type A in patients with vestibular migraine: A longitudinal fMRI study

Objective

This study aims to investigate the efficacy of botulinum toxin type A (BTX-A) in the prophylactic management of vestibular migraine (VM) and to determine whether this treatment modulates intrinsic functional brain network.

Methods

Vestibular migraine patients (n = 20, mean age 45.4 years) who were resistant to conventional prophylactic therapies had BTX-A injection and rs-fMRI before and 2 months after the injection. We also measured the changes in the frequency of vertigo and migraine attacks, symptomatic functional disability scores, and neuropsychiatric inventories.

Results

After BTX-A injection, the mean monthly frequencies of migraine and vertigo episodes decreased significantly compared with the baseline (p < 0.01, paired t-test). The Headache Impact Test-6 score and the Migraine Disability Assessment, and the vertigo parameters, measured by the Dizziness Handicap Inventory and the Vertigo Symptom Scale, showed an improvement, as did the anxiety and depression scores 2 months after BTX-A treatment. The low-frequency fluctuation analysis of the rs-fMRI data found significant changes in the functional connectivity of the right superior temporal gyrus. Adoption of this cluster as the seed region increased the functional connectivity with the left post-central gyrus, right supramarginal gyrus, and right middle temporal gyrus after BTX-A treatment.

Conclusion

This prospective study suggests that BTX-A treatment is effective at ameliorating migraine and vertigo symptoms in VM patients who were resistant to conventional therapies. Along with symptomatic improvements, changes in the functional connectivity within the multisensory vestibular and pain networks suggest a dysmodulation of multimodal sensory integration and abnormal cortical processing of the vestibular and pain signals in VM patients.