Iron deposition in periaqueductal gray matter as a potential biomarker for chronic migraine

Insights from 25 years of onabotulinumtoxinA in migraine - mechanisms and management

OnabotulinumtoxinA (BTX-A) was first linked to beneficial effects in migraine 25 years ago and was approved by the FDA for preventive treatment of chronic migraine in 2010. The treatment has since had a major impact on the well-being of people with chronic migraine. The clinical development programme for BTX-A and research since its approval have provided insights into the neuromodulatory sensory effect of BTX-A, how it can control chronic migraine despite its peripheral action, and the underlying biology of migraine as a disease. In this Review, we consider the impact that BTX-A has had on the management of chronic migraine and on the research field. We discuss the insights provided by clinical research, encompassing the clinical trials and subsequent real-world evidence, and the mechanistic insights provided by preclinical and translational research. We also provide an overview of future directions of research in the field BTX-A in migraine and the clinical translation of this research.

Gamma-aminobutyric acid and glutamate/glutamine levels in the dentate nucleus and periaqueductal gray in new daily persistent headache: a magnetic resonance spectroscopy study

BACKGROUND

Magnetic resonance spectroscopy (MRS) studies have indicated that the imbalance between gamma-aminobutyric acid (GABA) and glutamate/glutamine (Glx) levels was the potential cause of migraine development. However, the changes in the GABA and Glx levels in patients with New daily persistent headache (NDPH) remain unclear. This study aimed to investigate the changes in GABA and Glx levels in the periaqueductal gray (PAG) and dentate nucleus (DN) in patients with NDPH using the MEGA-PRESS sequence.

METHODS

Twenty-one NDPH patients and 22 age- and sex-matched healthy controls (HCs) were included and underwent a 3.0T MRI examination, using the MEGA-PRESS sequence to analyze GABA and Glx levels of PAG and DN. The correlations between these neurotransmitter levels and clinical characteristics were also analyzed.

RESULTS

There were no significant differences in the GABA+/Water, GABA+/Cr, Glx/Water, and Glx/Cr levels in both PAG and DN between the two groups (all p > 0.05). Moderate-severe NDPH patients had lower levels of Glx/Water (p = 0.034) and Glx/Cr (p = 0.012) in DN than minimal-mild NDPH patients. In patients with NDPH, higher Glx/Water levels in the PAG (r=-0.471, p = 0.031, n = 21) and DN (r=-0.501, p = 0.021, n = 21) and higher Glx/Cr levels in DN (r=-0.483, p = 0.026, n = 21) were found to be correlated with lower Visual Analogue Scale scores. Additionally, a positive correlation was observed between the GABA+/Cr levels in the DN and the Generalized Anxiety Disorder-7 scores (r = 0.519, p = 0.039, n = 16).

CONCLUSIONS

The results of this study indicated that the GABA and Glx levels in the PAG and DN may not be the primary contributor to the development of NDPH. The correlations between certain clinical scales and the neurotransmitter levels may be derived from the NDPH related symptoms.

Potential of ferroptosis and ferritinophagy in migraine pathogenesis

Objective

To assess the potential of ferroptosis and ferritinophagy in migraine pathogenesis.

Background

Ferroptosis and ferritinophagy are related to increased cellular iron concentration and have been associated with the pathogenesis of several neurological disorders, but their potential in migraine pathogenesis has not been explored. Increased iron deposits in some deep brain areas, mainly periaqueductal gray (PAG), are reported in migraine and they have been associated with the disease severity and chronification as well as poor response to antimigraine drugs.

Results

Iron deposits may interfere with antinociceptive signaling in the neuronal network in the brain areas affected by migraine, but their mechanistic role is unclear. Independently of the location, increased iron concentration may be related to ferroptosis and ferritinophagy in the cell. Therefore, both phenomena may be related to increased iron deposits in migraine. It is unclear whether these deposits are the reason, consequence, or just a correlate of migraine. Still, due to migraine-related elevated levels of iron, which is a prerequisite of ferroptosis and ferritinophagy, the potential of both phenomena in migraine should be explored. If the iron deposits matter in migraine pathogenesis, they should be mechanically linked with the clinical picture of the disease. As iron is an exogenous essential trace element, it is provided to the human body solely with diet or supplements. Therefore, exploring the role of iron in migraine pathogenesis may help to determine the potential role of iron-rich/poor dietary products as migraine triggers or relievers.

Conclusion

Ferroptosis and ferritinophagy may be related to migraine pathogenesis through iron deposits in the deep areas of the brain.

Prevalence of primary headaches in multiple sclerosis patients

BACKGROUND

Multiple sclerosis (MS) is the most common immune-mediated inflammatory disease of the central nervous system. It is characterized by symptoms such as visual disturbances, paresis with spasticity, paresthesia, numbness, and fatigue. However, several studies have shown a high prevalence of headaches in individuals with MS. Migraine and tension-type headaches are the most frequent types of headaches experienced by those with MS. Additionally, the role of MS disease-modifying agents must be considered. These agents have different modes of action and side effect profiles, and their use may sometimes trigger headaches in patients with MS.

OBJECTIVES

This study aimed to explore the prevalence and clinical characteristics of primary headaches in MS patients. The relationship between headache and clinical features of MS (Course of MS, duration, EDSS, brain imaging and DMD) are also investigated.

SUBJECTS AND METHODS

Two hundred and eighty-one MS patients diagnosed according to according to the 2017 revisions to the McDonald Criteria were included in the study. Data was collected from the MS unit medical records and from the interview with the patients. Patients with reported headaches are asked to recall their headache characteristics and patterns using an interviewer administered Arabic language-structured validated questionnaire.

RESULTS

The median age of patients was 33 years old, with a range of 22-55. Tension-type headache (TTH) was more common in males, patients with more severe disability (EDSS ≥ 3), and those with SPMS and PPMS phenotypes. Additionally, patients on rituximab or cyclophosphamide therapy were more likely to have TTH. On the other hand, females, patients with milder disability (EDSS < 3), and those with RRMS phenotype were more likely to have migraine. This was also true for patients with MRI lesions involving the periaqueductal gray, and those receiving INF or fingolimod (P < 0.05). Periaqueductal gray matter lesions were found in the MRI of 48 patients (40 %) who experienced headaches on more than 10 days per month. Sensorimotor lesions in the brain were found in 55 patients (53.4 %) with severe headaches (p-value < 0.001). Interferons were associated with an increased risk of worsening preexisting headaches and the appearance of de novo headaches related to its intake (odds ratio: 2.84, 3.72; relative risk: 1.63, 2.04; p-value = 0.03, < 0.001, respectively). On the other hand, rituximab was associated with a decreased risk of worsening preexisting headaches and the appearance of de novo headaches related to its intake (odds ratio: 0.04, 0.09; relative risk: 0.11, 0.18; p-value = < 0.001, < 0.001, respectively).

CONCLUSION

Primary headaches are a common occurrence in patients with MS. Migraines and tension-type headaches (TTH) are among the most prevalent types. It has been observed that interferon can exacerbate preexisting headaches and even cause new ones. Additionally, the location of MS plaques may play a role in the frequency and severity of headaches.

Medication "underuse" headache

BACKGROUND

Many risk factors have been associated with migraine progression, including insufficient and ineffective utilization of migraine medications; however, they have been inadequately explored. This has resulted in suboptimal usage of medications without effective altering of prescribing recommendations for patients, posing a risk for migraine chronification.

METHODS

Our aim is to conduct a comprehensive review of the available evidence regarding the underuse of migraine medications, both acute and preventive. The term "underuse" includes, but is not limited to: (1) ineffective use of appropriate and inappropriate medication; (2) underutilization; (3) inappropriate timing of usage; and (4) patient dissatisfaction with medication.

RESULTS

The underuse of both acute and preventive medications has been shown to contribute to the progression of migraine. In terms of acute medication, chronification occurs as a result of insufficient drug use, including failure of the prescriber to select the appropriate type based on pain intensity and disability, patients taking medication too late (more than 60 minutes after the onset or after central sensitization has occurred as evidenced by allodynia), and discontinuation because of lack of effect or intolerable side effects. The underlying cause of inadequate effectiveness of acute medication lies in its inability to halt the propagation of peripheral activation to central sensitization in a timely manner. For oral and injectable preventive migraine medications, insufficient efficacy and intolerable side effects have led to poor adherence and discontinuation with subsequent progression of migraine. The underlying pathophysiology here is rooted in the repetitive stimulation of afferent sensory pain fibers, followed by ascending brainstem pain pathways plus dysfunction of the endogenous descending brainstem pain inhibitory pathway. Although anti-calcitonin gene-related peptide (CGRP) medications partially address pain caused by the above factors, including decreased efficacy and tolerability from conventional therapy, some patients do not respond well to this treatment. Research suggests that initiating preventive anti-CGRP treatment at an early stage (during low frequency episodic migraine attacks) is more beneficial than commencing it during high frequency episodic attacks or when chronic migraine has begun.

CONCLUSIONS

The term "medication underuse" is underrecognized, but it holds significant importance. Optimal usage of acute care and preventive migraine medications could potentially prevent migraine chronification and improve the treatment of migraine attacks.

Retinal and peripapillary vascular density in episodic and chronic migraine cases without aura

BACKGROUND

Migraine is a neurovascular disease that can cause ocular and systemic ischemic damage. Despite from aura, a limited number of studies have considered the effect of the chronic migraine in cases without aura. Our aim was to evaluate the differences in the retinal and optic disk microvasculature among episodic and chronic migraine cases without aura using optical coherence tomography angiography (OCTA) imaging.

METHODS

45 cases with migraine, and 25 control subjects were included in this prospective, cross-sectional study. OCTA was performed at 3 × 3 mm and 6 × 6 mm of the macula and at 4.5 × 4.5 mm of the optic disk. Retinal nerve fiber layer (RNFL) thickness, ganglion cell complex thickness, and vessel densities of the optic nerve and macula were compared among the three groups: a control group, an episodic migraine without aura (EMWOA) group, and a chronic migraine without aura (CMWOA) group.

RESULTS

In EMWOA group, circumpapillary vascular density (cpVD) was not decreased significantly in any quadrants (all, p>0.05). Compared to the control group, CMWOA group had significantly lower RNFL thickness in superior-temporal quadrants (p = 0.002 and 0.006, respectively), while cpVD differed only in the temporal quadrant and temporal inferior sector (p = 0.002 and p = 0.009, respectively).

CONCLUSIONS

Temporal peripapillary perfusion is valuable in the follow-up of chronic migraine cases. Longitudinal studies are needed to determine the place of OCTA in the follow-up of migraine.

New management strategies for primary headache disorders: Insights from P4 medicine

Primary headache disorder is the main cause of headache attacks, leading to significant disability and impaired quality of life. This disorder is increasingly recognized as a heterogeneous condition with a complex network of genetic, environmental, and lifestyle factors. However, the timely diagnosis and effective treatment of these headaches remain challenging. Precision medicine is a potential strategy based on P4 (predictive, preventive, personalized, and participatory) medicine that may bring new insights for headache care. Recent machine learning advances and widely available molecular biology and imaging data have increased the usefulness of this medical strategy. Precision medicine emphasizes classifying headaches according to their risk factors, clinical presentation, and therapy responsiveness to provide individualized headache management. Furthermore, early preventive strategies, mainly utilizing predictive tools, are critical in reducing headache attacks and improving the quality of life of individuals with headaches. The current review comprehensively discusses the potential application value of P4 medicine in headache management.

Breaking the cycle: unraveling the diagnostic, pathophysiological and treatment challenges of refractory migraine

Background

Refractory migraine is a poorly described complication of migraine in which migraine has chronified and become resistant to standard treatments. The true prevalence is unknown, but medication resistance is common in headache clinic patient populations. Given the lack of response to treatment, this patient population is extremely difficult to treat with limited guidance in the literature.

Objective

To review the diagnostic, pathophysiological, and management challenges in the refractory migraine population.

Discussion

There are no accepted, or even ICHD-3 appendix, diagnostic criteria for refractory migraine though several proposed criteria exist. Current proposed criteria often have low bars for refractoriness while also not meeting the needs of pediatrics, lower socioeconomic status, and developing nations. Pathophysiology is unknown but can be hypothesized as a persistent "on" state as a progression from chronic migraine with increasing central sensitization, but there may be heterogeneity in the underlying pathophysiology. No guidelines exist for treatment of refractory migraine; once all guideline-based treatments are tried, treatment consists of n-of-1 treatment trials paired with non-pharmacologic management.

Conclusion

Refractory migraine is poorly described diagnostically, its pathophysiology can only be guessed at by extension of chronic migraine, and treatment is more the art than science of medicine. Navigating care of this refractory population will require multidisciplinary care models and an emphasis on future research to answer these unknowns.

Imaging the brain and vascular reactions to headache treatments: a systematic review

BACKGROUND

Neuroimaging studies have made an important contribution to our understanding of headache pathophysiology. This systematic review aims to provide a comprehensive overview and critical appraisal of mechanisms of actions of headache treatments and potential biomarkers of treatment response disclosed by imaging studies.

MAIN BODY

We performed a systematic literature search on PubMed and Embase databases for imaging studies investigating central and vascular effects of pharmacological and non-pharmacological treatments used to abort and prevent headache attacks. Sixty-three studies were included in the final qualitative analysis. Of these, 54 investigated migraine patients, 4 cluster headache patients and 5 patients with medication overuse headache. Most studies used functional magnetic resonance imaging (MRI) (n = 33) or molecular imaging (n = 14). Eleven studies employed structural MRI and a few used arterial spin labeling (n = 3), magnetic resonance spectroscopy (n = 3) or magnetic resonance angiography (n = 2). Different imaging modalities were combined in eight studies. Despite of the variety of imaging approaches and results, some findings were consistent. This systematic review suggests that triptans may cross the blood-brain barrier to some extent, though perhaps not sufficiently to alter the intracranial cerebral blood flow. Acupuncture in migraine, neuromodulation in migraine and cluster headache patients, and medication withdrawal in patients with medication overuse headache could promote headache improvement by reverting headache-affected pain processing brain areas. Yet, there is currently no clear evidence for where each treatment acts, and no firm imaging predictors of efficacy. This is mainly due to a scarcity of studies and heterogeneous treatment schemes, study designs, subjects, and imaging techniques. In addition, most studies used small sample sizes and inadequate statistical approaches, which precludes generalizable conclusions.

CONCLUSION

Several aspects of headache treatments remain to be elucidated using imaging approaches, such as how pharmacological preventive therapies work, whether treatment-related brain changes may influence therapy effectiveness, and imaging biomarkers of clinical response. In the future, well-designed studies with homogeneous study populations, adequate sample sizes and statistical approaches are needed.

Periaqueductal gray matter echogenicity as a marker of migraine chronification: a case control study

BACKGROUND

Migraine is one of the most prevalent and disabling medical diseases in the world. The periaqueductal gray matter and the red nucleus play an important role in its pathogenesis. Our aim was to evaluate the echogenicity of the periaqueductal gray matter and the red nucleus in patients with migraine, by means of transcranial ultrasound.

METHODS

In this cross-sectional study, a group of patients with migraine (according to the International Classification of Headache Disorders) and a group of control subjects with comparable age-and-sex distribution were prospectively included. We evaluated the area and echogenicity of the periaqueductal gray matter and the red nucleus by means of transcranial ultrasound, both bedside and posteriorly analyzed with the medical image viewer Horos.

RESULTS

We included 115 subjects: 65 patients with migraine (39 of them with chronic migraine and 26 with episodic migraine), and 50 controls. Median disease duration in patients with chronic migraine was 29 (IQR: 19; 40) years, with a median of 18 (IQR: 14; 27) days of migraine per month. The area of the periaqueductal gray matter was larger in patients with chronic migraine compared to episodic migraine and controls (0.15[95%CI 0.12;0.22]cm²; 0.11[95%CI 0.10;0.14]cm² and 0.12[95%CI 0.09;0.15]cm², respectively; p = 0.043). Chronic migraine patients showed an intensity of the periaqueductal gray matter echogenicity lower than controls (90.57[95%CI 70.87;117.26] vs 109.56[95%CI 83.30;122.64]; p = 0.035). The coefficient of variation of periaqueductal gray matter echogenicity was the highest in chronic migraine patients (p = 0.009). No differences were observed regarding the area or intensity of red nucleus echogenicity among groups.

CONCLUSION

Patients with chronic migraine showed a larger area of echogenicity of periaqueductal gray matter, a lower intensity of its echogenicity and a higher heterogenicity within this brainstem structure compared to patients with episodic migraine and controls. The echogenicity of the periaqueductal gray matter should be further investigated as a biomarker of migraine chronification.

Increased iron deposition in nucleus accumbens associated with disease progression and chronicity in migraine

BACKGROUND

Migraine is one of the world's most prevalent and disabling diseases. Despite huge advances in neuroimaging research, more valuable neuroimaging markers are still urgently needed to provide important insights into the brain mechanisms that underlie migraine symptoms. We therefore aim to investigate the regional iron deposition in subcortical nuclei of migraineurs as compared to controls and its association with migraine-related pathophysiological assessments.

METHODS

A total of 200 migraineurs (56 chronic migraine [CM], 144 episodic migraine [EM]) and 41 matched controls were recruited. All subjects underwent MRI and clinical variables including frequency/duration of migraine, intensity of migraine, 6-item Headache Impact Test (HIT-6), Migraine Disability Assessment (MIDAS), and Pittsburgh Sleep Quality Index (PSQI) were recorded. Quantitative susceptibility mapping was employed to quantify the regional iron content in subcortical regions. Associations between clinical variables and regional iron deposition were studied as well.

RESULTS

Increased iron deposition in the putamen, caudate, and nucleus accumbens (NAC) was observed in migraineurs more than controls. Meanwhile, patients with CM had a significantly higher volume of iron deposits compared to EM in multiple subcortical nuclei, especially in NAC. Volume of iron in NAC can be used to distinguish patients with CM from EM with a sensitivity of 85.45% and specificity of 71.53%. As the most valuable neuroimaging markers in all of the subcortical nuclei, higher iron deposition in NAC was significantly associated with disease progression, and higher HIT-6, MIDAS, and PSQI.

CONCLUSIONS

These findings provide evidence that iron deposition in NAC may be a biomarker for migraine chronicity and migraine-related dysfunctions, thus may help to understand the underlying vascular and neural mechanisms of migraine.

TRIAL REGISTRATION

ClinicalTrials.gov, number NCT04939922.

Biomarkers of Migraine: An Integrated Evaluation of Preclinical and Clinical Findings

In recent years, numerous efforts have been made to identify reliable biomarkers useful in migraine diagnosis and progression or associated with the response to a specific treatment. The purpose of this review is to summarize the alleged diagnostic and therapeutic migraine biomarkers found in biofluids and to discuss their role in the pathogenesis of the disease. We included the most informative data from clinical or preclinical studies, with a particular emphasis on calcitonin gene-related peptide (CGRP), cytokines, endocannabinoids, and other biomolecules, the majority of which are related to the inflammatory aspects and mechanisms of migraine, as well as other actors that play a role in the disease. The potential issues affecting biomarker analysis are also discussed, such as how to deal with bias and confounding data. CGRP and other biological factors associated with the trigeminovascular system may offer intriguing and novel precision medicine opportunities, although the biological stability of the samples used, as well as the effects of the confounding role of age, gender, diet, and metabolic factors should be considered.

Structural MRI in Migraine: A Review of Migraine Vascular and Structural Changes in Brain Parenchyma

Migraine is a complex and common disorder that affects patients around the world. Despite recent advances in this field, the exact pathophysiology of migraine is still not completely understood. Structural MRI sequences have revealed a variety of changes to brain parenchyma associated with migraine, including white matter lesions, volume changes, and iron deposition. This Review highlights different structural imaging findings in various types of migraine and their relationship to migraine characteristics and subtypes in order to improve our understanding of migraine, its pathophysiologic mechanisms, and how to better diagnose and treat it.

Longitudinal changes in functional connectivity and pain-induced brain activations in patients with migraine: a functional MRI study pre- and post- treatment with Erenumab

Abstract

Background

Migraine involves central and peripheral nervous system mechanisms. Erenumab, an anti-calcitonin gene-related peptide (CGRP) receptor monoclonal antibody with little central nervous system penetrance, is effective for migraine prevention. The objective of this study was to determine if response to erenumab is associated with alterations in brain functional connectivity and pain-induced brain activations.

Methods

Adults with 6–25 migraine days per month during a 4-week headache diary run-in phase underwent pre-treatment brain functional MRI (fMRI) that included resting-state functional connectivity and BOLD measurements in response to moderately painful heat stimulation to the forearm. This was followed by two treatments with 140 mg erenumab, at baseline and 4 weeks later. Post-treatment fMRI was performed 2 weeks and 8 weeks following the first erenumab treatment. A longitudinal Sandwich estimator analysis was used to identify pre- to post-treatment changes in resting-state functional connectivity and brain activations in response to thermal pain. fMRI findings were compared between erenumab treatment-responders vs. erenumab non-responders.

Results

Pre- and post-treatment longitudinal imaging data were available from 32 participants. Average age was 40.3 (+/− 13) years and 29 were female. Pre-treatment average migraine day frequency was 13.8 (+/− 4.7) / 28 days and average headache day frequency was 15.8 (+/− 4.4) / 28 days. Eighteen of 32 (56%) were erenumab responders. Compared to erenumab non-responders, erenumab responders had post-treatment differences in 1) network functional connectivity amongst pain-processing regions, including higher global efficiency, clustering coefficient, node degree, regional efficiency, and modularity, 2) region-to-region functional connectivity between several regions including temporal pole, supramarginal gyrus, and hypothalamus, and 3) pain-induced activations in the middle cingulate, posterior cingulate, and periaqueductal gray matter.

Conclusions

Reductions in migraine day frequency accompanying erenumab treatment are associated with changes in resting state functional connectivity and central processing of extracranial painful stimuli that differ from erenumab non-responders.

Trial registration

clinicaltrials.gov (NCT03773562).

A c-Fos activation map in nitroglycerin/levcromakalim-induced models of migraine

Background

Chronic migraine is a common and highly disabling disorder. Functional MRI has indicated that abnormal brain region activation is linked with chronic migraine. Drugs targeting the calcitonin gene-related peptide (CGRP) or its receptor have been reported to be efficient for treating chronic migraine. The CGRP signaling was also shared in two types of chronic migraine models (CMMs). However, it remains unclear whether the activation of specific brain regions could contribute to persistent behavioral sensitization, and CGRP receptor antagonists relieve migraine-like pain in CMMs by altering specific brain region activation. Therefore, it’s of great interest to investigate brain activation pattern and the effect of olcegepant (a CGRP receptor-specific antagonist) treatment on alleviating hyperalgesia by altering brain activation in two CMMs, and provide a reference for future research on neural circuits.

Methods

Repeated administration of nitroglycerin (NTG) or levcromakalim (LEV) was conducted to stimulate human migraine-like pain and establish two types of CMMs in mice. Mechanical hypersensitivity was evaluated by using the von Frey filament test. Then, we evaluated the activation of different brain regions with c-Fos and NeuN staining. Olcegepant was administered to explore its effect on mechanical hyperalgesia and brain region activation.

Results

In two CMMs, acute and basal mechanical hyperalgesia was observed, and olcegepant alleviated mechanical hyperalgesia. In the NTG-induced CMM, the medial prefrontal cortex (mPFC), anterior cingulate cortex (ACC), and the caudal part of the spinal trigeminal nucleus (Sp5c) showed a significant increase of c-Fos expression in the NTG group (p < 0.05), while pre-treatment with olcegepant reduced c-Fos expression compared with NTG group (p < 0.05). No significant difference of c-Fos expression was found in the paraventricular thalamic nucleus (PVT) and ventrolateral periaqueductal gray (vlPAG) between the vehicle control and NTG group (p > 0.05). In the LEV-induced CMM, mPFC, PVT, and Sp5c showed a significant increase of c-Fos expression between vehicle control and LEV group, and olcegepant reduced c-Fos expression (p < 0.05). No significant difference in c-Fos expression was found in vlPAG and ACC (p > 0.05).

Conclusions

Our study demonstrated the activation of mPFC and Sp5c in two CMMs. Olcegepant may alleviate hyperalgesia of the hind paw and periorbital area by attenuating brain activation in CMMs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-022-01496-8.

Association of a Cyclical Migraine Phenotype With Disease Progression: A One-Year Time Series Analysis

OBJECTIVE

Longitudinal studies assessing cyclic fluctuations of migraine attacks using time-series analysis are scarce. Here we analyze headache frequency fluctuations over a year in a cohort of migraine patients and we then evaluate how this behaviour has an impact on clinical evolution.

METHODS

Monthly headache frequency was prospectively collected using an eDiary. Prognosis after one year was calculated as the headache frequency change rate after 12 months (HCR-M12) as a dependent variable. Monthly headache time series was decomposed into all the possible sum of sinusoids through a Fast Fourier Transform algorithm (FFT) and the frequencies with the highest power were used to define the patient's cyclic phenotype during one year (patient's number of cycles per year, c/y). Patients with a cyclic phenotype were those with >2 cycles/year. Finally, we studied how this cyclic phenotype was associated to HCR-M12 using Generalized Linear Models (GLM).

RESULTS

142 patients were included (85.2% female; mean age 48.0±9.7 years), 50.0% fulfilled IHCD-3 criteria for chronic migraine (CM). After one year, a 50.7% (72/142) of patients changed their initial diagnosis and progression (frequency worsening) was observed in 14.1% (10/71) of episodic migraine (EM) patients. After applying a FFT, 45.1% (64/142) of patients fitted into a cyclic phenotype. In GLM, statistically significant main effects associated to HCR-M12 were the use of preventive therapy (Beta [SE]: 74.1 [34.6]; p=0.034) and cyclic phenotype (Beta [SE]: 158.33 [55.1]; p=0.005). A post-hoc analysis found that EM patients with cyclic phenotype without adequate preventive therapy were statistically significantly associated to progression.

CONCLUSIONS

Monthly headache frequency data can be fitted by sinusoidal models. Having a cyclic phenotype has an impact on clinical evolution and has been statistically significantly associated to migraine progression after one year. Particularly, EM patients with cyclic phenotype tend to increase their headache frequency over time. Preventive treatment seems to play a fundamental role in modulating this cyclic behaviour, especially in low-frequency EM patients.

Neurobiology of migraine progression

Chronic migraine is one of the most devastating headache disorders. The estimated prevalence is 1.4-2.2% in the population. The factors which may predispose to the process of migraine progression include high frequency of migraine attacks, medication overuse, comorbid pain syndromes, and obesity. Several studies showed that chronic migraine results in the substantial anatomical and physiological changes in the brain. Despite no clear explanation regarding the pathophysiologic process leading to the progression, certain features such as increased sensory sensitivity, cutaneous allodynia, impaired habituation, identify the neuronal hyperexcitability as the plausible mechanism. In this review, we describe two main mechanisms which can lead to this hyperexcitability. The first is persistent sensitization caused by repetitive and prolonged trigeminal nociceptive activation. This process results in changes in several brain networks related to both pain and non-pain behaviours. The second mechanism is the decrease in endogenous brainstem inhibitory control, hence increasing the excitability of neurons in the trigeminal noceptive system and cerebral cortex. The combination of increased pain matrix connectivity, including hypothalamic hyperactivity and a weak serotonergic system, may contribute to migraine chronification.

Gamma-aminobutyric acid and glutamate/glutamine levels in the dentate nucleus and periaqueductal gray with episodic and chronic migraine: a proton magnetic resonance spectroscopy study

Background

The pathogenesis of migraine chronification remains unclear. Functional and structural magnetic resonance imaging studies have shown impaired functional and structural alterations in the brains of patients with chronic migraine. The cerebellum and periaqueductal gray (PAG) play pivotal roles in the neural circuits of pain conduction and analgesia in migraine. However, few neurotransmitter metabolism studies of these migraine-associated regions have been performed. To explore the pathogenesis of migraine chronification, we measured gamma-aminobutyric acid (GABA) and glutamate/glutamine (Glx) levels in the dentate nucleus (DN) and PAG of patients with episodic and chronic migraine and healthy subjects.

Methods

Using the MEGA-PRESS sequence and a 3-Tesla magnetic resonance scanner (Signa Premier; GE Healthcare, Chicago, IL, USA), we obtained DN and PAG metabolite concentrations from patients with episodic migraine (n = 25), those with chronic migraine (n = 24), and age-matched and sex-matched healthy subjects (n = 16). Patients with chronic migraine were further divided into those with (n = 12) and without (n = 12) medication overuse headache. All scans were performed at the Beijing Tiantan Hospital, Capital Medical University.

Results

We found that patients with chronic migraine had significantly lower levels of GABA/water (p = 0.011) and GABA/creatine (Cr) (p = 0.026) in the DN and higher levels of Glx/water (p = 0.049) in the PAG than healthy controls. In all patients with migraine, higher GABA levels in the PAG were significantly associated with poorer sleep quality (GABA/water: r = 0.515, p = 0.017, n = 21; GABA/Cr: r = 0.522, p = 0.015, n = 21). Additionally, a lower Glx/Cr ratio in the DN may be associated with more severe migraine disability (r = -0.425, p = 0.055, n = 20), and lower GABA/water (r = -0.424, p = 0.062, n = 20) and Glx/Water (r = -0.452, p = 0.045, n = 20) may be associated with poorer sleep quality.

Conclusions

Neurochemical levels in the DN and PAG may provide evidence of the pathological mechanisms of migraine chronification. Correlations between migraine characteristics and neurochemical levels revealed the pathological mechanisms of the relevant characteristics.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-022-01452-6.

TOP-PRO study: A randomized double-blind controlled trial of topiramate versus propranolol for prevention of chronic migraine

OBJECTIVE

The aim of the TOP-PRO-study, a double-blind randomized controlled trial, was to assess the efficacy (non-inferiority) and tolerability of propranolol compared to topiramate for the prevention of chronic migraine.

BACKGROUND

Except for topiramate, oral preventive treatment for chronic migraine lacks credible evidence.

METHODS

Chronic migraine patients aged above 18 years and less than 65 years of age, not on any preventive treatment were randomly allocated to receive topiramate (100 mg/day) or propranolol (160 mg/day). The primary efficacy outcome was the mean change in migraine days per 28 days at the end of 24 weeks from baseline. A mean difference of 1.5 days per four weeks was chosen as the cut-off delta value. Multiple secondary efficacy outcomes and treatment emergent adverse events were also assessed.

RESULTS

As against the planned sample size of 244, only 175 patients could be enrolled before the spread of the corona virus disease-2019 pandemic and enforcement of lockdown in India. Of the 175 randomized patients, 95 (topiramate 46 and propranolol 49) completed the trial. The mean change in migraine days was -5.3 ± 1.2 vs -7.3 ± 1.1 days (p = 0.226) for topiramate and propranolol groups respectively. Propranolol was found to be non-inferior and not superior to topiramate (point estimate of -1.99 with a 95% confidence interval of -5.23 to 1.25 days). Multiple secondary outcomes also did not differ between the two groups. Intention to treat analysis of 175 patients and per-protocol analysis of 95 patients yielded concordant results. There was no significant difference in the incidence of adverse events between the two groups.

CONCLUSION

Propranolol (160mg/day) was non-inferior, non-superior to topiramate (100mg/day) for the preventive treatment of chronic migraine and had a comparable tolerability profile.Trial Registration: Clinical Trials Registry-India CTRI/2019/05/018997).

Breathing Abnormalities During Sleep and Wakefulness in Rett Syndrome: Clinical Relevance and Paradoxical Relationship With Circulating Pro-oxidant Markers

Background

Breathing abnormalities are common in Rett syndrome (RTT), a pervasive neurodevelopmental disorder almost exclusively affecting females. RTT is linked to mutations in the methyl-CpG-binding protein 2 (MeCP2) gene. Our aim was to assess the clinical relevance of apneas during sleep-wakefulness cycle in a population with RTT and the possible impact of apneas on circulating oxidative stress markers.

Methods

Female patients with a clinical diagnosis of typical RTT (n = 66), MECP2 gene mutation, and apneas were enrolled (mean age: 12.5 years). Baseline clinical severity, arterial blood gas analysis, and red blood cell count were assessed. Breathing was monitored during the wakefulness and sleep states (average recording time: 13 ± 0.5 h) with a portable polygraphic screening device. According to prevalence of breath holdings, the population was categorized into the wakefulness apnea (WA) and sleep apnea (SA) groups, and apnea-hypopnea index (AHI) was calculated. The impact of respiratory events on oxidative stress was assessed by plasma and intra-erythrocyte non-protein-bound iron (P-NPBI and IE-NPBI, respectively), and plasma F2-isoprostane (F2-IsoP) assays.

Results

Significant prevalence of obstructive apneas with values of AHI &gt; 15 was present in 69.7% of the population with RTT. The group with SA showed significantly increased AHI values &gt; 15 (p = 0.0032), total breath holding episodes (p = 0.007), and average SpO2 (p = 0.0001) as well as lower nadir SpO2 (p = 0.0004) compared with the patients with WAs. The subgroups of patients with WA and SA showed no significant differences in arterial blood gas analysis variables (p &gt; 0.089). Decreased mean cell hemoglobin (MCH) (p = 0.038) was observed in the group with WAs. P-NPBI levels were significantly higher in the group with WA than in that with SAs (p = 0.0001). Stepwise multiple linear regression models showed WA being related to nadir SpO2, average SpO2, and P-NPBI (adjusted R2 = 0.613, multiple correlation coefficient = 0.795 p &lt; 0.0001), and P-NPBI being related to average SpO2, blood PaCO2, red blood cell mean corpuscular volume (MCV), age, and topiramate treatment (adjusted R2 = 0.551, multiple correlation coefficient = 0.765, p &lt; 0.0001).

Conclusion

Our findings indicate that the impact of apneas in RTT is uneven according to the sleep-wakefulness cycle, and that plasma redox active iron represents a potential novel therapeutic target.

The increased iron deposition of the gray matter over the whole brain in chronic migraine: an exploratory quantitative susceptibility mapping study

Background

Prior studies identified iron deposition in deep brain nuclei and the periaqueductal gray matter region in chronic migraine, and less is known about the cerebral iron deposition over the whole cerebral gray matter in CM. The aim of this case–control study is to investigate the cerebral iron deposition of gray matter in CM using an advanced quantitative susceptibility mapping.

Methods

A multi-echo gradient echo MR sequence was used to obtain raw quantitative susceptibility mapping data from 12 CM patients and 18 normal controls and the quantitative susceptibility mapping were reconstructed. Three dimensional T1 images were segmented and the gray matter mask was generated to extract the susceptibility value of gray matter over the whole brain. The independent t test and receiver operating characteristic curve Receiver operating characteristics was used to investigate the iron deposition changes in CM patients.

Results

CM presented a higher susceptibility value (1.44 × 10⁻³ ppm) compared with NC group (0.47 × 10⁻³ ppm) (p < 0.0001) over the whole cerebral gray matter. There was no correlation between susceptibility value and the clinical variables including disease duration, Visual Analog Scale (VAS), Migraine Disability Assessment Scale (MIDAS), Hamilton Anxiety Scale (HAMA), Hamilton Depression Scale (HAMD), and Montreal Cognitive Assessment (MoCA) scores (p > 0.05). ROC analysis demonstrated the susceptibility had a high diagnostic efficacy (AUC 0.949, sensitivity 77.78% and specificity 100%) in distinguishing CM from NC.

Conclusion

CM patients had increased iron deposition in total cerebral gray matter which could be considered as a potential diagnostic and evaluated imaging biomarker in CM.

Evidence That HFE H63D Variant Is a Potential Disease Modifier in Cluster Headache

Cluster headache (CH) is a primary headache disorder with a complex genetic background. Several studies indicate a potential link between iron homeostasis and the pathophysiology of primary headaches. The HFE gene encodes for a protein involved in iron metabolism, while genetic variants in HFE have been associated with hereditary hemochromatosis (HH), an iron overload disorder. The objective of the current study was to examine the association of the more common HFE H63D variant, with the susceptibility to develop CH and diverse clinical phenotypes in a population of Southeastern European Caucasian (SEC) origin. Genomic DNA samples from 128 CH patients and 294 neurologically healthy controls were genotyped for the HFE rs1799945 (H63D) variant. H63D genotypic and allelic frequency distribution did not differ significantly between patients and controls (p > 0.05). Subgroup analysis revealed a significantly more frequent occurrence of the variant G allele in chronic compared to episodic CH patients, indicative for a possible correlation of the HFE gene with the susceptibility for disease chronification. Although homozygosity for the less prevalent H63D variant G allele was minimal in the CH cohort, the results of the present study are in accordance with previous studies in CH and migraine patients, suggesting that HFE H63D variant modifies the disease clinical characteristics. Hence, despite the absence of a per se association with CH susceptibility in the current SEC cohort, variability in HFE gene may be potentially regarded as a disease modifier genetic factor in CH.

A volumetric magnetic resonance imaging study in migraine

Background

Although migraine phenotype has been widely described, the explanation of migraine pathophysiology still has a gap that might be partly bridged by neuroimaging investigations. The aim of the study is to assess volumetric brain changes in migraineurs compared with controls, and in episodic migraine in comparison to chronic type. Structural brain changes in migraineurs (with and without aura) were assessed by an automated segmentation method (Free Surfer). T1-weighted MRIs of 25 migraineurs (14 diagnosed as episodic type and 11 diagnosed as chronic migraine) and 25 headache-free controls were evaluated and processed.

Results

Migraine patients had significant reduction of the volume of total brain, grey matter, brain stem, cerebellum, basal ganglia, thalamus, hippocampus and amygdala in comparison to control subjects. Patients with chronic migraine had significant reduction in volume of total brain, grey matter, cerebellum and frontal lobe thickness in comparison to those with episodic migraine.

Conclusion

Migraineurs showed volumetric brain changes mainly in areas related to central processing of pain and in areas specific for migraine (such as brain stem) when compared to healthy controls. Chronic migraineurs showed significant reduction in grey matter, in areas involved in processing of pain, cognition and multisensory integration versus patients with episodic migraine, which adds insight into the pathophysiology of migraine as a progressive disorder that may have long-term impacts on the brain as regards structure and function.

Chronic Migraine Pathophysiology and Treatment: A Review of Current Perspectives

Chronic migraine is a disabling neurological disorder that imposes a considerable burden on individual and socioeconomic outcomes. Chronic migraine is defined as headaches occurring on at least 15 days per month with at least eight of these fulfilling the criteria for migraine. Chronic migraine typically evolves from episodic migraine as a result of increasing attack frequency and/or several other risk factors that have been implicated with migraine chronification. Despite this evolution, chronic migraine likely develops into its own distinct clinical entity, with unique features and pathophysiology separating it from episodic migraine. Furthermore, chronic migraine is characterized with higher disability and incidence of comorbidities in comparison to episodic migraine. While existing migraine studies primarily focus on episodic migraine, less is known about chronic migraine pathophysiology. Mounting evidence on aberrant alterations suggest that pronounced functional and structural brain changes, central sensitization and neuroinflammation may underlie chronic migraine mechanisms. Current treatment options for chronic migraine include risk factor modification, acute and prophylactic therapies, evidence-based treatments such as onabotulinumtoxinA, topiramate and newly approved calcitonin gene-related peptide or receptor targeted monoclonal antibodies. Unfortunately, treatments are still predominantly ineffective in aborting migraine attacks and decreasing intensity and frequency, and poor adherence and compliance with preventative medications remains a significant challenge. Novel emerging chronic migraine treatments such as neuromodulation offer promising therapeutic approaches that warrant further investigation. The aim of this narrative review is to provide an update of current knowledge and perspectives regarding chronic migraine background, pathophysiology, current and emerging treatment options with the intention of facilitating future research into this debilitating and largely indeterminant disorder.

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

Background

To describe interictal brain structural and metabolic differences between patients with episodic migraine (EM), chronic migraine (CM) and healthy controls (HC).

Methods

This is an exploratory study including right-handed age-matched women with EM, CM and HC. On the same day, a sequential interictal scan was performed with ¹⁸FDG-PET and MRI. 3D T1-weighted images were segmented with FreeSurfer, normalized to a reference atlas and the mean values of metabolism, cortical thickness (CTh) and local gyrification index (IGI) were determined. Groups were compared using age-adjusted linear models, corrected for multiple comparisons. ¹⁸FDG-PET measurements between groups were also analysed adjusting by patient’s age, CTh and lGI. The variables independently associated with diagnosis were obtained using a logistic regression analysis.

Results

Fifteen patients (8 EM, 7 CM) and 11 HC were included. Morphometric data showed an increased CTh in 6 frontal areas (L/R-Caudal Middle Frontal, L/R-Rostral Middle Frontal, L-Medial Orbitofrontal and L-Superior Frontal) in CM patients compared to HC without differences for IGI. The structural adjusted analysis in CM showed a statistically significantly hypometabolism in 9 frontal areas (L-Lateral Orbitofrontal, L/R-Medial Orbitofrontal, L-Frontal Superior, R-Frontal pole, R-Parts Triangularis, L/R-Paracentral and R-Precentral) and 7 temporal areas (L/R-Insula, L/R-Inferior temporal, L/R-Temporal pole and R-Banks superior temporal sulcus) compared to HC. EM patients presented intermediate metabolic values ​​between EM and HC (non-significant).

Conclusions

CM patients showed frontotemporal hypometabolism and increased frontal cortical thickness when compared to HC that may explain some cognitive and behavioural pain-processing and sensory integration alterations in CM patients. Combined information from sequential or simultaneous PET and MRI could optimize the study of complex functional neurological disorders such as migraine.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-021-01289-5.

Association Between Dietary Iron Intake and Serum Ferritin and Severe Headache or Migraine

Background: Dietary iron intake and serum ferritin in relation to severe headache or migraine remain largely unknown. Therefore, we investigated the associations between dietary iron intake and serum ferritin with severe headache or migraine among American adults. Methods: This cross-sectional study included 7,880 adults (≥20 years) from the National Health and Nutrition Examination Surveys (NHANES) of America from 1999 to 2004. We performed multivariable logistic regression and restricted cubic spline (RCS) regression to assess the association of dietary iron and serum ferritin with severe headache or migraine. Results: Most women aged 20-50 years consumed less dietary iron than their recommended dietary allowances. Dietary iron intake was inversely associated with severe headache or migraine in women aged 20-50 years. For women over 50 years, serum ferritin was negatively associated with severe headache or migraine. For men, there was no significant relationship between dietary iron and serum ferritin, and severe headache or migraine. Conclusions: Dietary iron intake has different effects on migraine in women of different ages, and this different effect may be due to age-related menstrual changes. Women aged 20-50 years should have a higher awareness of RDA and increase their dietary iron intake if needed, which may play an important role in preventing severe headache or migraine. Higher serum ferritin levels in women aged 50 and above may have a protective effect against migraine.

OnabotulinumtoxinA in Migraine: A Review of the Literature and Factors Associated with Efficacy

The efficacy of onabotulinumtoxinA (OnaB-A) as a preventative treatment for chronic migraine, emerging fortuitously from clinical observation is now supported by class one evidence and over two decades of real-world clinical data. There is still limited ability to predict a clinically meaningful response to OnaB-A for individual patients, however. This review summarises briefly the proposed mechanism of OnaB-A in chronic migraine, the literature of predictors of clinical response, and recent developments in the field.

Biomarkers in Migraine

Background

Disability from migraine has a profound impact on the world's economy. Research has been ongoing to identify biomarkers to aid in diagnosis and treatment.

Objective

The aim of this study was to highlight the purported diagnostic and therapeutic migraine biomarkers and their role in precision medicine.

Methods

A comprehensive literature search was conducted using PubMed, Google Scholar, and clinicaltrials.gov using keywords: "migraine" OR "headache" combined with "biomarkers" OR "marker." Other keywords included "serum," "cerebral spinal fluid," "inflammatory," and "neuroimaging."

Results

After a review of 88 papers, we find the literature supports numerous biomarkers in the diagnosis of migraine. Therapeutic biomarkers, while not as extensively published, highlight calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase-activating peptide-38 (PACAP-38) as biomarkers with the most substantiated clinical relevance. Genetic markers mainly focusing on gene mutations with resultant biochemical alterations continue to be studied and show promise.

Conclusion

Although there are several proposed biomarkers for migraine, continued research is needed to substantiate their role in clinical practice.

Association and genetic overlap between clinical chemistry tests and migraine

INTRODUCTION

In this paper, we studied several serum clinical chemistry tests of cardiovascular disease (CVD), iron deficiency anemia, liver and kidney disorders in migraine.

METHODS

We first explored the association of 22 clinical chemistry tests with migraine risk in 697 migraine patients and 2722 controls. To validate and interpret association findings, cross-trait genetic analyses were conducted utilising genome-wide association study (GWAS) data comprising 23,986 to 452,264 individuals.

RESULTS

Significant associations with migraine risk were identified for biomarkers of CVD risk, iron deficiency and liver dysfunction (odds ratios = 0.86-1.21; 1 × 10^-4 < p < 3 × 10^-2). Results from cross-trait genetic analyses corroborate the significant biomarker associations and indicate their relationship with migraine is more consistent with biological pleiotropy than causality. For example, association and genetic overlap between a lower level of HDL-C and increased migraine risk are due to shared biology rather than a causal relationship. Furthermore, additional genetic analyses revealed shared genetics among migraine, the clinical chemistry tests, and heart problems and iron deficiency anemia, but not liver disease.

CONCLUSIONS

These findings highlight common biological mechanisms underlying migraine, heart problems and iron deficiency anemia and provide support for their investigation in the development of novel therapeutic and dietary interventions.

Voxel-based quantitative susceptibility mapping revealed increased cerebral iron over the whole brain in chronic migraine

Background

The previous documents demonstrated that iron deposition was identified in brain deep nuclei and periaqueductal gray matter region in chronic migraine (CM), and less is known about the cerebral iron deposition in CM. The aim of this study is to investigate the cerebral iron deposition in CM using an advanced voxel-based quantitative susceptibility mapping.

Methods

A multi-echo gradient echo MR sequence was obtained from 14 CM patients and 28 normal controls (NC), and quantitative susceptibility mapping images were reconstructed and voxel-based analysis was performed over the whole cerebrum. The susceptibility value of all the positive brain regions was extracted and correlation was calculated between the susceptibility value and the clinical variables.

Results

The brain regions with increased susceptibility value in CM patients located in right precuneus, insula, supramarginal gyrus, dorsolateral superior frontal gyrus, postcentral gyrus, cuneus and left postcentral gyrus compared with NC. The correlation analysis demonstrated that a positive correlation was identified between susceptibility value of all the positive brain regions and VAS score.

Conclusion

The current study demonstrated increased cerebral iron deposition presented in chronic patients, which suggested that increased cerebral iron deposition might play a role in the migraine chronicization.

Hypoechogenicity of the midbrain raphe detected by transcranial sonography: an imaging biomarker for depression in migraine patients

Background

The high comorbidity of migraine and depression is suggestive of shared risk factors or common mechanisms between the two diseases. In individuals with a depressive disorder, there is a high prevalence of altered midbrain raphe (MBR) echogenicity, detectable via transcranial sonography (TCS), that is suggested to be linked with a dysfunction of the serotoninergic system. In patients with migraine, this alteration has seldom been explored in earlier studies, and conclusions are often lacking. Our study aimed to elucidate whether this alteration is specific to migraine and to determine whether it is related with depression.

Methods

This study enrolled patients with migraine (n = 100, 72% female) and patients with tension-type headache disorders (TTH) (n = 62, 78.5% female) from a headache clinic. In addition, 79 healthy subjects (79.7% female) were recruited as controls. All participants underwent a standard interview to evaluate headache information and an interview with psychiatrists for depression evaluation. TCS examinations were performed on all participants.

Results

Patients with migraine had a higher rate of MBR hypoechogenicity (28%) compared with that of healthy controls (15.2%) and that of patients with TTH (12.9%). In patients with migraine, reduced MBR echogenicity was associated with depressive symptoms assessed using the Hamilton Depression Rating Scale (HAM-D). No association between migraine self-medication and MBR echogenicity was found.

Conclusion

Reduced-echoic MBR detected by TCS is prevalent in migraine patients and is associated with depressive symptoms. TCS-detected hypoechogenic MBR abnormality could be an imaging biomarker of depressive symptoms in patients with migraine.

The Role of Endothelial Dysfunction in the Pathophysiology and Cerebrovascular Effects of Migraine: A Narrative Review

Background and Purpose

Migraine is a complex neurovascular disorder whose triggers are not entirely understood. Endothelial dysfunction might play a role in migraine, and there have been numerous reports on endothelium dysfunction and migraine pathophysiology, but their reciprocal cause–effect relationship remains unclear. This review reports the current evidence on endothelium dysfunction, its link with migraine, and its possible consequences for cerebral hemodynamics.

Methods

We performed a systematic literature search of PubMed up to March 2020. We included 115 articles in a narrative review.

Results

Several studies have demonstrated that endothelium dysfunction may play an important role in migraine. Despite the lack of specific biomarkers, there is evidence of oxidative stress and inflammation—two of the primary causes of endothelial damage—in migraine. The main consequences of endothelial dysfunction are increased vascular tone, thrombosis, inflammation, and increased vascular permeability. As a consequence of oxidative stress, the activity of endothelin-1 is not counterbalanced by nitric oxide (NO), whose levels decrease to lead to vasoconstriction and a possible contribution to cortical spreading depression. NO is involved in pain perception via the cyclic guanosine monophosphate (cGMP) pathway and the induction of calcitonin gene-related peptide. Oxidative stress may induce a hypercoagulable state that mainly affects platelet function through different mechanisms. Endothelial dysfunction seems to be particularly pronounced in migraine with aura (MA). Endothelial dysfunction in migraine particularly involves intracranial vessels, since flow-mediated dilation cannot detect overt peripheral vascular dysfunction.

Conclusions

Endothelial dysfunction is a vascular risk marker. How it impacts migraine, and particularly MA, needs to be understood better by defining its possible role in increasing the stroke risk in migraine patients.

How does the brain change in chronic migraine? Developing disease biomarkers

BACKGROUND

Validated chronic migraine biomarkers could improve diagnostic, prognostic, and predictive abilities for clinicians and researchers, as well as increase knowledge on migraine pathophysiology.

OBJECTIVE

The objective of this narrative review is to summarise and interpret the published literature regarding the current state of development of chronic migraine biomarkers.

FINDINGS

Data from functional and structural imaging, neurophysiological, and biochemical studies have been utilised towards the development of chronic migraine biomarkers. These biomarkers could contribute to chronic migraine classification/diagnosis, prognosticating patient outcomes, predicting response to treatment, and measuring treatment responses early after initiation. Results show promise for using measures of brain structure and function, evoked potentials, and sensory neuropeptide concentrations for the development of chronic migraine biomarkers, yet further optimisation and validation are still required.

CONCLUSIONS

Imaging, neurophysiological, and biochemical changes that occur with the progression from episodic to chronic migraine could be utilised for developing chronic migraine biomarkers that might assist with diagnosis, prognosticating individual patient outcomes, and predicting responses to migraine therapies. Ultimately, validated biomarkers could move us closer to being able to practice precision medicine in the field and thus improve patient care.

Red nucleus structure and function: from anatomy to clinical neurosciences

The red nucleus (RN) is a large subcortical structure located in the ventral midbrain. Although it originated as a primitive relay between the cerebellum and the spinal cord, during its phylogenesis the RN shows a progressive segregation between a magnocellular part, involved in the rubrospinal system, and a parvocellular part, involved in the olivocerebellar system. Despite exhibiting distinct evolutionary trajectories, these two regions are strictly tied together and play a prominent role in motor and non-motor behavior in different animal species. However, little is known about their function in the human brain. This lack of knowledge may have been conditioned both by the notable differences between human and non-human RN and by inherent difficulties in studying this structure directly in the human brain, leading to a general decrease of interest in the last decades. In the present review, we identify the crucial issues in the current knowledge and summarize the results of several decades of research about the RN, ranging from animal models to human diseases. Connecting the dots between morphology, experimental physiology and neuroimaging, we try to draw a comprehensive overview on RN functional anatomy and bridge the gap between basic and translational research.

Migraine and Sleep in Children: A Bidirectional Relationship

Migraine and sleep disorders in children exhibit a bidirectional relationship. This relationship is based on shared pathophysiology. Migraine involves activation of the trigeminal vascular system. Nociceptive neurons that innervate the dura release various vasoactive peptides. Calcitonin gene-related peptide is the most active of these peptides. Neural pathways that are involved in sleep generation are divided into those responsible for circadian rhythm, wake promotion, non-rapid eye movement, and rapid eye movement sleep activation. Sleep state switches are a critical component of these systems. The cerebral structures, networks, and neurochemical systems that are involved in migraine align closely with those responsible for the regulation of sleep. Neurochemical systems that are involved with both the pathogenesis of migraine and regulation of sleep include adenosine, melatonin, orexin, and calcitonin gene-related peptide. Sleep disorders represent the most common comorbidity with migraine in childhood. The prevalence of parasomnias, obstructive sleep apnea, and sleep-related movement disorders is significantly greater in children migraineurs. Infantile colic is a precursor of childhood migraine. Treatment of comorbid sleep disorders is important for the appropriate management of children with migraine. Sleep-based behavioral interventions can be of substantial benefit. These interventions are particularly important in children due to limited evidence for effective migraine pharmacotherapy.

Iron Deposits in Periaqueductal Gray Matter Are Associated with Poor Response to OnabotulinumtoxinA in Chronic Migraine

Previous studies have reported increased brain deposits of iron in patients with chronic migraine (CM). This study aims to determine the relation between iron deposits and outcome after treatment with OnabotulinumtoxinA (OnabotA). Demographic and clinical data were collected for this study through a prospective cohort study including 62 CM patients treated with OnabotA in the Hospital Clínico Universitario de Santiago de Compostela (Spain). Demographic and clinical variables were registered. Selected biomarkers in plasma during interictal periods (calcitonin gene-related peptide (CGRP) and pentraxin-3 (PTX3)) and neuroimaging changes (iron deposits in the red nucleus (RN), substantia nigra (SN), globus pallidus (GP), and periaqueductal gray matter (PAG), and white matter lesions (WML)) were determined. Subjects were classified in responders (≥50% reduction in headache days) or non-responders (<50%). Responders to treatment were younger (mean age difference = 12.2; 95% confidence interval (CI): 5.4–18.9, p = 0.001), showed higher serum levels of CGRP (≥50 ng/mL) and PTX3 (≥1000 pg/mL) and smaller iron deposits in the GP and PAG (mean difference = 805.0; 95% CI: 37.9–1572.1 μL, p = 0.040 and mean difference = 69.8; 95% CI: 31.0–108.6 μL, p = 0.008; respectively). Differences in PAG iron deposits remained significant after adjusting for age (mean difference = 65.7; 95% CI: 22.8–108.6 μL, p = 0.003) and were associated with poor response to OnabotA after adjustment for clinical and biochemical variables (odds ratio (OR) = 0.963; 95% CI: 0.927–0.997, p = 0.041). We conclude that larger PAG iron deposits are associated with poor response to OnabotA in CM.

An Update: Pathophysiology of Migraine

Migraine is the most common disabling primary headache globally. Attacks typically present with unilateral throbbing headache and associated symptoms including, nausea, multisensory hypersensitivity, and marked fatigue. In this article, the authors address the underlying neuroanatomical basis for migraine-related headache, associated symptomatology, and discuss key clinical and preclinical findings that indicate that migraine likely results from dysfunctional homeostatic mechanisms. Whereby, abnormal central nervous system responses to extrinsic and intrinsic cues may lead to increased attack susceptibility.

From transformation to chronification of migraine: pathophysiological and clinical aspects

Chronic migraine is a neurological disorder characterized by 15 or more headache days per month of which at least 8 days show typical migraine features. The process that describes the development from episodic migraine into chronic migraine is commonly referred to as migraine transformation or chronification. Ample studies have attempted to identify factors associated with migraine transformation from different perspectives. Understanding CM as a pathological brain state with trigeminovascular participation where biological changes occur, we have completed a comprehensive review on the clinical, epidemiological, genetic, molecular, structural, functional, physiological and preclinical evidence available.

Tibetan medicine Ru-yi-Zhen-bao Pills exhibits anti-migraine effect through mediating PAG anti-nociceptive channel

ETHNOPHARMACOLOGICAL RELEVANCE

Migraine is a disabling neurovascular disorder, which increases risk of cardiovascular events and is a social burden worldwide. The present first-line anti-migraine medications can cause overwhelming side-effects, of which one includes the onset of cardiovascular disease. As one of the marketed Tibetan drugs, Ru-yi-Zhen-bao Pills (RYZBP) have been clinically used to treat cardiovascular disorders and as anti-migraine medication. However, there is currently no research exploring the anti-migraine actions of RYZBP.

AIM OF THE STUDY

The current research was designed to assess the anti-migraine roles of RYZBP and explore the underlying mechanisms in a nitroglycerin (NTG)-induced migraine rat model trial.

MATERIALS AND METHODS

120 rats were randomly divided into the following six groups of 20 rats each: normal control group, model control group, positive control group, and RYZBP high/medium/low-dose groups (Ru-yi-Zhen-bao Pills; TH 1.00 g/kg, TM 0.50 g/kg and TL 0.25 g/kg). All rats were administered intragastrically for 7 consecutive days, which were subcutaneously injected with the NTG (10 mg/kg) after the last gavage (except in the normal control group). 3min after NTG treatment, 30 rats (5 rats from each group) were anesthetized and devoted to electroencephalogram(EEG) testing, which was used to evaluate the analgesic effect of RYZBP. One hour after NTG treatment, the rest of the 90 rats (15 rats from each group) were anesthetized and midbrain tissue sample was dissected. The dissection was then washed with physiological saline and collected. The histopathological changes in the periaqueductal gray(PAG) of 5 tissue samples were determined by aematoxylin-eosin (H&E) staining, as well as an estimation of substance P (SP) and neurokinin 1 receptor (NK1R) expression through immunohistochemically staining(IHC). Another 5 midbrain preparations were carried out to evaluate calcitonin gene-related peptide (CGRP), proenkephalin (PENK), SP, and cholecystokinin (CCK) expressions by real-time quantitative polymerase chain reaction (RT-qPCR). The rest of the 5 brainstem tissues were then used to measure CCK, CGRP, and opioid peptide receptor (DORR) levels by western blotting(WB).

RESULTS

In the EEG test, RYZBP (TM 0.50 g / kg) treatment transformed the EEG pain-wave of the NTG-induced migraine model rats in different time period. In the mechanism assay, compared with the model control group, RYZBP pretreatment reduced inflammatory cell infiltration, fibrosis and vacuolation of neuronal cells of PAG tissue seen by HE staining. IHC experiments further showed that RYZBPTM up-regulated SP expression levels and enhanced NK1R levels in the NTG-induced migraine rats (P < 0.05). Therapeutic administration of RYZBP also increased PENK mRNA expression and DORR protein level. Both RT-qPCR and western blotting trials indicated that RYZBP treatment significantly decreased CCK and CGRP expression levels (P < 0.01 or P < 0.05) in the NTG-induced migraine rats.

CONCLUSIONS

RYZBP has the potential to be an effective anti-migraine treatment through suppressing the EEG pain-wave, increasing the levels of SP, PENK, DORR and reducing expression of CCK and CGRP. Mediating the PAG anti-nociceptive channel and inhibiting central sensitization were the two potential mechanisms, which offers further evidence for clinical therapy.

The Chronic Migraine Brain: What Have We Learned From Neuroimaging?

Chronic migraine is a highly disabling disease with a great impact on socioeconomic functioning and quality of life of migraine patients. Chronic migraine usually evolves from episodic migraine that gradually increases in attack frequency, supporting the view of migraine as a spectrum disorder. Pathophysiological mechanisms responsible for migraine chronification are not fully understood. Likewise episodic migraine, chronic migraine patients show widespread functional and structural alterations of cortical and subcortical pain-related brain areas. However, chronic migraine patients experience a more pronounced dysfunction of the pain inhibitory network and an increased sensitization of the central pain pathways, which might explain the higher susceptibility to migraine attacks. Imaging studies have highlighted that brain regions with a key role in migraine attack generation, like the pons and hypothalamus, might also be involved in migraine chronification. Whether brain alterations are biomarkers that predispose migraine patients to chronification or reflect adaptive or maladaptive responses to the increasing headache frequency is still a matter of debate. The central mechanisms of action of chronic migraine preventive treatments and imaging biomarkers that could predict patients' treatment response have also been explored. In this new era of migraine treatments, a better understanding of chronic migraine pathophysiology will pave the way for the development of new improved treatments specifically designed for chronic migraine patients.

Regional volume changes of the brain in migraine chronification

The pathophysiology of migraine is complex. Neuroimaging studies reveal functional and structural changes in the brains of migraine patients. We sought to explore regional volume differences in intracranial structures in patients with episodic and chronic migraine. Sixteen episodic migraine patients, 16 chronic migraine patients, and 24 normal controls were recruited and underwent 3.0 T MRI scanning. The volumes of 142 brain regions were calculated by an automatic volumetric algorithm and compared with clinical variables. Results demonstrated that the volumes of specific regions in the frontal and occipital lobes, and the right putamen, were increased and the volume of the fourth ventricle was decreased in the episodic migraine patients compared with controls. The volumes of the left basal forebrain, optic chiasm, and, the fourth ventricle were decreased in the chronic migraine patients, while the occipital cortex and the right putamen were larger. Compared to episodic migraine patiants, chronic migraine patients displayed larger left thalamus and smaller frontal regions. Correlation analysis showed that headache frequency was negatively correlated with the volume of the right frontal pole, right lateral orbital gyrus, and medial frontal lobes and positively correlated with the volume of the left thalamus. The sleep disturbance score was negatively correlated with the volume of the left basal forebrain. This suggests that migraine patients have structural changes in regions associated with pain processing and modulation, affective and cognitive processing, and visual perception. The remodeling of selective intracranial structures may be involved in migraine attacks. This study was approved by the Ethics Committee of Chinese PLA General Hospital (approval No. S2018-027-02) on May 31, 2018.

Hsa-miR-34a-5p and hsa-miR-375 as Biomarkers for Monitoring the Effects of Drug Treatment for Migraine Pain in Children and Adolescents: A Pilot Study

MicroRNAs (miRs) have emerged as biomarkers of migraine disease in both adults and children. In this study we evaluated the expression of hsa-miR-34a-5p and hsa-miR-375 in serum and saliva of young subjects (age 11 ± 3.467 years) with migraine without aura (MWA), while some underwent pharmacological treatment, and healthy young subjects were used as controls. miRs were determined using the qRT-PCR method, and gene targets of hsa-miR-34a-5p and hsa-miR-375 linked to pain-migraine were found by in silico analysis. qRT-PCR revealed comparable levels of hsa-miRs in both blood and saliva. Higher expression of hsa-miR-34a-5p and hsa-miR-375 was detected in saliva of untreated MWAs compared to healthy subjects (hsa-miR-34a-5p: p < 0.05; hsa-miR-375 p < 0.01). Furthermore, in MWA treated subjects, a significant decrease of hsa-miR-34a-5p and of hsa-miR-375 was documented in saliva and blood compared to MWA untreated ones. Altogether, these findings suggested thathsa-miR-34a-5p and hsa-miR-375 are expressed equally in blood and saliva and that they could be a useful biomarker of disease and of drug efficacy in patients with MWA.