Tracking tDCS induced grey matter changes in episodic migraine: a randomized controlled trial

Background Occipital transcranial direct current stimulation (tDCS) is an effective and safe treatment for migraine attack prevention. Structural brain alterations have been found in migraineurs in regions related to pain modulation and perception, including occipital areas. However, whether these structural alterations can be dynamically modulated through tDCS treatment is understudied. Objective To track longitudinally grey matter volume changes in occipital areas in episodic migraineurs during and up to five months after occipital tDCS treatment in a single-blind, and sham-controlled study. Methods 24 episodic migraineurs were randomized to either receive verum or sham occipital tDCS treatment for 28 days. To investigate dynamic grey matter volume changes patients underwent structural MRI at baseline (prior to treatment), 1.5 months and 5.5 months (after completion of treatment). 31 healthy controls were scanned with the same MRI protocol. Morphometry measures assessed rate of changes over time and between groups by means of tensor-based morphometry. Results Before treatment, migraineurs reported 5.6 monthly migraine days on average. A cross-sectional analysis revealed grey matter volume increases in the left lingual gyrus in migraineurs compared to controls. Four weeks of tDCS application led to a reduction of 1.9 migraine days/month and was paralleled by grey matter volume decreases in the left lingual gyrus in the treatment group; its extent overlapping with that seen at baseline. Conclusion This study shows that migraineurs have increased grey matter volume in the lingual gyrus, which can be modified by tDCS. Tracking structural plasticity in migraineurs provides a potential neuroimaging biomarker for treatment monitoring. Trial registration ClinicalTrials.gov, NCT03237754. Registered 03 August 2017 – retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03237754.

Efficacy and safety of exogenous beta-hydroxybutyrate for preventive treatment in episodic migraine: A single-centred, randomised, placebo-controlled, double-blind crossover trial

Background Several studies propose that brain energy deficit might be partially involved in the pathophysiology of migraine. Previously, studies demonstrated that ketogenic diet causes a substantial reduction in migraine frequency. Since the ketogenic diet is restricting and its adherence is difficult, we proposed to supplement ketone bodies exogenously to provide a prophylactic effect in migraineurs. Aim To evaluate the prophylactic effect of exogenous DL-beta-hydroxybutyrate supplementation in episodic migraineurs. Methods A double-blind, placebo-controlled, randomised crossover trial was conducted, involving 41 patients with episodic migraine. Patients were randomised 1:1 into placebo or beta-hydroxybutyrate group before entering the first treatment period. Each treatment period was 12 weeks long, followed by four weeks of washout phase and four weeks of run-in phase before entering into the corresponding second treatment period. The primary endpoint was the number of migraine days in the last four weeks of treatment, adjusted for baseline. Results We observed no clinically significant amelioration of migraine frequency or intensity under DL-beta-hydroxybutyrate treatment as compared to placebo regarding number of migraine days (mean difference [95% CI]: −1.1[−5.07, 2.85]), migraine intensity (0–10 VAS: 1.5[−0.8, 3.7]). Conclusion The selected dose of supplemented exogenous DL-beta-hydroxybutyrate did not demonstrate efficacy in episodic migraineurs. ClinicalTrials.gov Identifier: NCT03132233

Cerebral Iron Concentration in Episodic Migraineurs

Objective: To investigate cerebral iron concentrations in patients with episodic migraine and investigate correlations with clinical parameters, such as monthly migraine days or disease duration.Methods: We included episodic migraineurs and healthy controls from 18 to 80 years; headache diaries were kept during a four-week baseline period. All participants underwent MRI scans, including a multi-echo 3D gradient recalled echo sequence that allowed calculating quantitative susceptibility maps.We performed whole-brain analyses comparing the iron level of healthy controls and migraineurs and searched for regions in which migraineurs’ iron concentrations correlated with their migraine frequency or disease duration. The significance level was set at 0.001 (uncorrected), the extent threshold at ten voxels.Results: We included 15 patients and 18 controls. There were several brain regions such as the anterior cingulate cortex and the middle frontal gyrus, in which migraineurs stored more iron, but none in which controls had higher iron levels. Iron correlated positively with migraine frequency or disease duration in multiple brain regions. There was one region in which iron load correlated negatively with disease duration.Conclusions: Migraine predisposes to increased iron levels. Not every brain area with an altered iron concentration is active during migraine attacks, so perhaps the increased iron might not solely be due to migraine but to a common cause, such as a metabolic or information processing disorder.

The effects of vitamin D3 supplementation on TGF-β and IL-17 serum levels in migraineurs: post hoc analysis of a randomized clinical trial

Background Although the exact mechanism involved in migraine pathogenesis remained uncertain, and different researches have been developed to address the role of neuroinflammation and immune dysfunction. Therefore, considering the immune protective functions of vitamin D3, we aimed to investigate the effects of daily administration of 2000 IU D3 supplements on serum status of immune markers in migraine patients. Methods and materials Eighty episodic migraineurs who randomly assigned into two equal groups to receive either vitamin D3 2000 IU/d or placebo for 12-week were enrolled in this placebo-controlled double-blind trial included. Serum concentrations of transforming growth factor-beta (TGF-β) and interleukin (IL)-17 were evaluated at baseline and after the trial via the ELISA method. Results Applying ANCOVA adjusted for baseline levels and confounding variables, it was found that the serum level of TGF-β was significantly higher in vitamin D group (adjusted mean:1665.50 ng/L) than the placebo group (1361.90 ng/L) after the experiment (P-value = 0.012); on the other hand, vitamin D prevented the increment in IL-17 serum level in the intervention group after the trial (adjusted mean:37.84 ng/L) comparing to the controls (adjusted mean:70.09 ng/L; P-value = 0.039). The Pearson correlation analysis revealed a significant positive correlation between changes in serum 25-hydroxy-vitamin D (25(OH)D) and TGF-β (r = − 0.306, P-value = 0.008). In contrast, no significant correlations were noted between serum 25(OH) D and IL-17 changes throughout the study. Conclusion Based on the results of this study, it was revealed that 12-week vitamin D3 supplementation (2000 IU/day) could enhance the Th17/Treg related cytokines balance in episodic migraineurs. Although these findings are promising, it is needed to be extended. Trial registration The trial is registered in the Iranian registry of clinical trials (IRCT) at 11 July 2018, with IRCT code: IRCT20151128025267N6 (https://www.irct.ir/trial/31246).

The Instant Effects of Continuous Transcutaneous Auricular Vagus Nerve Stimulation at Acupoints on the Functional Connectivity of Amygdala in Migraine without Aura: A Preliminary Study

Background. A growing body of evidence suggests that both auricular acupuncture and transcutaneous auricular vagus nerve stimulation (taVNS) can induce antinociception and relieve symptoms of migraine. However, their instant effects and central treatment mechanism remain unclear. Many studies proved that the amygdalae play a vital role not only in emotion modulation but also in pain processing. In this study, we investigated the modulation effects of continuous taVNS at acupoints on the FC of the bilateral amygdalae in MwoA. Methods. Thirty episodic migraineurs were recruited for the single-blind, crossover functional magnetic resonance imaging (fMRI) study. Each participant attended two kinds of eight-minute stimulations, taVNS and sham-taVNS (staVNS), separated by seven days in random order. Finally, 27 of them were included in the analysis of seed-to-voxel FC with the left/right amygdala as seeds. Results. Compared with staVNS, the FC decreased during taVNS between the left amygdala and left middle frontal gyrus (MFG), left dorsolateral superior frontal gyrus, right supplementary motor area (SMA), bilateral paracentral lobules, bilateral postcingulum gyrus, and right frontal superior medial gyrus, so did the FC of the right amygdala and left MFG. A significant positive correlation was observed between the FC of the left amygdala and right SMA and the frequency/total time of migraine attacks during the preceding four weeks. Conclusion. Continuous taVNS at acupoints can modulate the FC between the bilateral amygdalae and pain-related brain regions in MwoA, involving the limbic system, default mode network, and pain matrix, with obvious differences between the left amygdala and the right amygdala. The taVNS may produce treatment effects by modulating the abnormal FC of the amygdala and pain networks, possibly having the same central mechanism as auricular acupuncture.

An underrepresented majority: A systematic review utilizing allodynic criteria to examine the present scarcity of discrete animal models for episodic migraine

Background Despite increasing evidence differentiating episodic and chronic migraine, little work has determined how currently utilized animal models of migraine best represent each distinct disease state. Aim In this review, we seek to characterize accepted preclinical models of migraine-like headache by their ability to recapitulate the clinical allodynic features of either episodic or chronic migraine. Methods From a search of the Pu bMed database for “animal models of migraine”, “headache models” and “preclinical migraine”, we identified approximately 80 recent (within the past 20 years) publications that utilized one of 10 different models for migraine research. Models reviewed fit into one of the following categories: Dural KCl application, direct electrical stimulation, nitroglycerin administration, inflammatory soup injection, CGRP injection, medication overuse, monogenic animals, post-traumatic headache, specific channel activation, and hormone manipulation. Recapitulation of clinical features including cephalic and extracephalic hypersensitivity were evaluated for each and compared. Discussion Episodic migraineurs comprise over half of the migraine population, yet the vast majority of current animal models of migraine appear to best represent chronic migraine states. While some of these models can be modified to reflect episodic migraine, there remains a need for non-invasive, validated models of episodic migraine to enhance the clinical translation of migraine research.

Evaluation of Inflammatory State in Migraineurs: A Case-control Study

Due to inconclusive findings of previous researches, we aimed to evaluate inflammatory state biomarkers in episodic and chronic migraineurs (EM and CM patients) compared to headache-free controls in the current study. Seventy-one migraine patients and 19 age-sex-matched controls were recruited. After obtaining demographic data and recording headache characteristics, blood samples were gathered and analyzed to evaluate the serum levels of C-reactive protein(CRP), tumor necrosis factor (TNF)-α and interleukin (IL)-6. Serum levels of IL-6, CRP and TNF-α were significantly higher among subjects with CM than the EM and controls. Further, positive correlations were noted for number of headache days/month and serum IL-6 (r=0.53, p<0.001), CRP (r=0.62, p<0.001), and TNF-α (r=0.58, p<0.001). In sum, according to current findings, a pro-inflammatory state was detected among chronic and episodic migraineurs compared to healthy control, as revealed by augmented concentrations of pro-inflammatory cytokines (e.g. IL6, CRP, and TNF-α). It was also underlined that with increasing levels of inflammatory factors, headaches tended to be more chronic. However, in order to confirm the hypothesis that neuroinflammation plays a role in migraine pain genesis, long-term cohort studies and well-designed experimental and randomized controlled trials are required.

Functional magnetic resonance imaging of regional impaired cerebrovascular reactivity for migraineurs in the interictal state

ABSTRACTThere is still an unmet need of mapping the potential impairment of cerebrovascular reactivity (CVR) in episodic migraineurs in the interictal state. We mapped CVR of 6 episodic migraineurs and 5 headache-free controls (HC) with blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) under carbon dioxide (CO2) challenge of 30-second epochs with elevated end-tidal partial pressure of CO2 (PETCO2) by 4-8mmHg. Three migraineurs have migraine without aura (MOA) and the other three have migraine with aura (MA). We found that only MOA subjects showed a reduced or negative BOLD response to CO2 at the red nucleus. All 3 MOA subjects were characterized by bilateral posterior communicating artery hypoplasia (bPCAH) identified by MR angiography (MRA). MOA and HC subjects did not show any significant difference in BOLD responses to CO2 challenge in cortical and white matter while MA subjects showed poor positive association between BOLD responses and PETCO2 in large territories of the cortex and white matter tracts. The combined use of fMRI under CO2 challenge and MRA presented a unique approach to investigate the mechanisms of episodic migraine in the interictal state demonstrating for the first time negative CVR at the red nucleus of the midbrain in patients with MOA. CVR maps obtained from both the midbrain and cortical regions provided various signatures to explore the differences between migraineurs and HC and between MOA and MA.

Self-perceived attention difficulties are associated with sensory hypersensitivity in migraine

Objectives: The aim of the study was to investigate potential interactions between sensory hypersensitivity and attentional difficulties in migraineurs. Methods: Forty-six episodic migraineurs without aura and 46 healthy controls filled out questionnaires on self-perceived attention difficulties and self-reported sensitivity to visual, auditory and olfactory stimulations.Results: Compared to controls, migraineurs reported significantly higher levels of attention difficulty and sensory sensitivity. Sensory hypersensitivity correlated significantly with attentional difficulties in migraineurs (p=0.002), but not with migraine disability or levels of anxiety or depression. Ictal and interictal sensory sensitivity were significantly correlated in migraineurs within visual (p&lt;.001), auditory (p&lt;.001) and olfactory (p=.001) modalities. Conclusion: Self-reported attentional difficulties, multimodal sensory hypersensitivity and the association between both may reflect the fact that external stimuli engage attention in an exacerbated manner in migraineurs, yielding distraction.

The effects of a multispecies probiotic supplement on inflammatory markers and episodic and chronic migraine characteristics: A randomized double-blind controlled trial

Background The current study was designed to assess the effect of supplementation with a 14-strain probiotic mixture on episodic and chronic migraine characteristics. Methods Forty episodic and 39 chronic migraine patients who completed this randomized double-blind controlled trial received two capsules of multispecies probiotic or placebo. The migraine severity was assessed by visual analog scale (VAS). The number of abortive drugs consumed, migraine days, frequency and duration of attacks were recorded on paper-based headache diaries. Serum tumor necrosis factor alpha (TNF-α) and C- reactive protein (CRP) levels were measured at baseline and the end of the intervention. Results After a 10-week intervention, among episodic migraineurs the mean frequency of migraine attacks significantly reduced in the probiotic group compare to the placebo group (mean change: −2.64 vs. 0.06; respectively, p < 0.001). A significant reduction was also evident in the migraine severity (mean decrease: −2.14 in the probiotic group and 0.11 in the placebo group; p < 0.001). Episodic migraineurs who received the probiotic also showed significant reduction in abortive drug usage per week (mean change: −0.72; p < 0.001) compare to baseline, while there was no significant changes within the placebo group. In chronic migraine patients, after an 8-week intervention, the mean frequency of migraine attacks significantly reduced in the probiotic compared to the placebo group (mean change: −9.67 vs. −0.22; p ≤ 0.001). In contrast to the placebo, probiotic supplementation significantly decreased the severity (mean changes: −2.69; p ≤ 0.001), duration (mean changes: −0.59; p ≤ 0.034) of attacks and the number of abortive drugs taken per day (mean changes: −1.02; p < 0.001), in chronic migraine patients. We failed to detect any significant differences in the serum levels of inflammatory markers at the end of the study either in chronic or in episodic migraineurs. Discussion The results of this study showed that the 14-strain probiotic mixture could be an effective and beneficial supplement to improve migraine headache in both chronic and episodic migraineurs. Further research is required to confirm our observations.