The role of cytokines in migraine: A systematic review

Does physical activity and inflammation mediate the job stress-headache relationship? A sequential mediation analysis in the ELSA-Brasil study

BACKGROUND

Evidence indicates that physical activity reduces stress and promote a myriad of health-enhancing effects through anti-inflammatory mechanisms. However, it is unknown whether these mechanisms interfere in the association between psychosocial job stress and headache disorders.

OBJECTIVE

To test whether physical activity and its interplay with the systemic inflammation biomarkers high-sensitivity C-reactive protein (hs-CRP) and acute phase glycoproteins (GlycA) would mediate the associations between job stress and headache disorders.

METHODS

We cross-sectionally evaluated the baseline data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) regarding job stress (higher demand and lower control and support subscales), migraine and tension-type headache (ICHD-2 criteria), self-reported leisure-time physical activity, and plasma hs-CRP and GlycA levels. Conditional process analyses with a sequential mediation approach were employed to compute path coefficients and 95 % confidence intervals (CI) around the indirect effects of physical activity and biomarkers on the job stress-headache relationship. Separate models were adjusted for sex, age, and depression and anxiety. Further adjustments added BMI smoking status, and socioeconomic factors.

RESULTS

In total, 7,644 people were included in the study. The 1-year prevalence of migraine and tension-type headache were 13.1 % and 49.4 %, respectively. In models adjusted for sex, age, anxiety, and depression, the association between job stress (lower job control) and migraine was mediated by physical activity [effect = -0.039 (95 %CI: -0.074, -0.010)] but not hs-CRP or GlycA. TTH was associated with higher job control and lower job demand, which was mediated by the inverse associations between physical activity and GlycA [Job Control: effect = 0.0005 (95 %CI: 0.0001, 0.0010); Job Demand: effect = 0.0003 (95 %CI: 0.0001, 0.0007]. Only the mediating effect of physical activity in the job stress-migraine link remained after further adjustments including socioeconomic factors, BMI, smoking, and the exclusion of major chronic diseases.

CONCLUSION

In the ELSA-Brasil study, physical activity reversed the link between job stress and migraine independently of systemic inflammation, while the LTPA-mediated downregulation of GlycA was associated with lower job stress-related TTH.

IL18 rs360717 and rs187238 genetic variants are associated with migraine diagnosis

BACKGROUND

Migraine is a genetically determined disorder that predisposes to recurrent episodes of headache. Interleukin (IL)-18 is a pro-inflammatory cytokine that seems to play a role in migraine pathophysiology, and its genetic variants could potentially impact susceptibility to migraine.

OBJECTIVE

To investigate the association between IL18 rs360717 and rs187238 genetic variants with migraine diagnosis and its clinical characteristics.

METHODS

A case-control study was conducted with 152 people with migraine and 155 healthy controls, matched by sex, age, ethnicity, and body mass index. Clinical characteristics of migraine, as well as validated questionnaires regarding disability and impact of migraine, presence of allodynia, anxiety, depression, and hyperacusis were collected. Genotyping for IL18 rs360717 and rs187238 variants was performed using real-time polymerase chain reaction (qPCR) and TaqMan™ method.

RESULTS

The IL18 rs360717A and rs187238G alleles were associated with increased chance of being diagnosed with migraine (OR = 1.53, 95%CI 1.05-2.24, p = 0.028 and OR = 1.46, 95%CI 1.00-2.14, p = 0.049, respectively). In the dominant model, the rs360717GA + AA genotypes were also associated with a higher chance of migraine than the GG genotype (OR = 1.69, 95%CI 1.05-2.73, p = 0.030). In women, in addition to the previous associations, there was also an effect of the variants on the chance of migraine in the codominant models and dominant models. Furthermore, among women, there was an influence on the prevalence of postdrome perception with rs360717GA + AA (OR = 3.04, 95%CI 1.10-8.42, p = 0.032) and rs187238CG + GG (OR = 2.97, 95%CI 1.08-8.21, p = 0.035).

CONCLUSION

IL18 rs360717 and rs187238 variants were associated with migraine diagnosis and postdrome symptoms, especially in women.

SIGNIFICANCE

This study has demonstrated that IL18 rs360717 and rs187238 variants play a role in migraine, influencing the chance of being diagnosed with migraine, particularly among women. There are prospects that IL18 variants could be considered potential genetic biomarkers for migraine.

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

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

The impact of genetic factors on the response to migraine therapy

Migraine is a multidimensional disease affecting a large portion of the human population presenting with a variety of symptoms. In the era of personalized medicine, successful migraine treatment presents a challenge, as several studies have shown the impact of a patient's genetic profile on therapy response. However, with the emergence of contemporary treatment options, there is promise for improved outcomes. A literature search was conducted in PubMed and Scopus, in order to obtain studies investigating the impact of genetic factors on migraine therapy outcome. Overall, 23 studies were included in the current review, exhibiting diversity in the treatments used and the genetic variants investigated. Divergent genes were assessed for each category of migraine treatment. Several genetic factors were identified to contribute to the heterogeneous response to treatment. SNPs related to pharmacodynamic receptors, pharmacogenetics and migraine susceptibility loci were the most investigated variants, revealing some interesting significant results. To date, various associations have been recorded correlating the impact of genetic factors on migraine treatment responses. More extensive research needs to take place with the aim of shedding light on the labyrinthine effects of genetic variations on migraine treatment, and, consequently, these findings can promptly affect migraine treatment and improve migraine patients' life quality in the vision of precise medicine.

Approach to the Diagnosis and Treatment of Headache

Headache is consistently one of the most common complaints reported by patients in the medical setting worldwide. Headache can be a symptom of another condition or illness, secondary to the disruption of homeostasis, or can be a primary disorder with inherent variability and patterns. Headache disorders, whether primary or secondary, can cause significant disability and loss of quality of life for those affected. As such, it is important for primary care providers to feel confident evaluating and treating patients with headache, especially given the limited access to Headache Medicine subspecialists.

Identifying novel proteins for migraine by integrating proteomes from blood and CSF with genome-wide association data

BACKGROUND

Proteome-wide Mendelian randomization studies have been increasingly utilized to identify potential drug targets for diseases. We aimed to identify potential therapeutic targets for migraine and its subtypes through the application of Mendelian randomization and co-localization analysis methods.

METHODS

We utilized cis-protein quantitative trait loci data for 1378 plasma proteins available from two studies with 7213 individuals and 35,559 individuals, respectively. Summary data for migraine and its subtypes were obtained from a genetic study involving up to 1,339,303 individuals. Proteins that passed both the discovery and validation Mendelian randomization analysis, sensitivity analysis, heterogeneity test, and pleiotropy test, were associated with ≥2 outcomes, and received strong support from co-localization analysis (PP.H4.abf ≥0.80) and were classified as tier 1 proteins.

RESULTS

We identified three tier 1 proteins (LRP11, ITIH1, and ADGRF5), whose genes have not been previously identified as causal genes for migraine in genetic studies. LRP11 was significantly associated with the risk of any migraine (OR [odds ratio] = 0.968, 95% CI [confidence interval] = 0.955-0.981, p = 1.27 × 10-6) and significantly/suggestively associated with three migraine subtypes. ITIH1 was significantly associated with the risk of any migraine (OR = 1.044, 95% CI = 1.024-1.065, p = 1.08 × 10-5) and migraine with visual disturbances. ADGRF5 was significantly associated with the risk of any migraine (OR = 0.964, 95% CI = 0.946-0.982, p = 8.74 × 10-5) and suggestively associated with migraine with aura. The effects of LRP11 and ADGRF5 were further replicated using cerebrospinal fluid protein data. Apart from ADGRF5, there was no evidence of potential adverse consequences when modulating the plasma levels. We also identified another four proteins (PLCG1, ARHGAP25, CHGA, and MANBA) with no potential adverse consequences when modulating the plasma levels, and their genes were not reported by previous genetic studies.

CONCLUSIONS

We found compelling evidence for two proteins and suggestive evidence for four proteins that could be promising targets for migraine treatment without significant adverse consequences. The corresponding genes were not reported in previous genetic studies. Future studies are needed to confirm the causal role of these proteins and explore the underlying mechanisms.

Astrocyte-Microglia Crosstalk: A Novel Target for the Treatment of Migraine

Migraine is a pervasive neurologic disease closely related to neurogenic inflammation. The astrocytes and microglia in the central nervous system are vital in inducing neurogenic inflammation in migraine. Recently, it has been found that there may be a crosstalk phenomenon between microglia and astrocytes, which plays a crucial part in the pathology and treatment of Alzheimer's disease and other central nervous system diseases closely related to inflammation, thus becoming a novel hotspot in neuroimmune research. However, the role of the crosstalk between microglia and astrocytes in the pathogenesis and treatment of migraine is yet to be discussed. Based on the preliminary literature reports, we have reviewed relevant evidence of the crosstalk between microglia and astrocytes in the pathogenesis of migraine and summarized the crosstalk pathways, thereby hoping to provide novel ideas for future research and treatment.

Association between the dietary inflammatory index and pain in US adults from NHANES

OBJECTIVES

The growing global burden of pain is gradually expanding from the medical field to public health. Dietary inflammatory potential correlates with inflammatory markers, and inflammation is one of the main mechanisms of pain.

METHODS

This study explored the association between dietary inflammatory index (DII) and pain from the NHANES database on DII and pain (neck pain, low back pain, joint pain, and headache or migraine) using logistic regression and stratified analysis.

RESULTS

The results show a stronger association between DII and joint pain (Q4 of DII adjusted-OR = 1.23, 95% CI = 1.08-1.40, P = 0.003) and headache or migraine (Q4 of DII adjusted-OR = 1.31, 95% CI = 1.15-1.48, P < 0.001), but no association is found in neck pain (Q4 of DII adjusted-OR = 1.03, 95% CI = 0.89-1.20, P = 0.65) and low back pain (Q4 of DII adjusted-OR = 1.04, 95% CI = 0.92-1.17, P = 0.54). After stratifying the data according to demographics, differences in the relationship between DII and pain are found at different levels of the population.

DISCUSSION

This study identifies high DII as a risk factor for joint pain and headache or migraine.

Oxidative Stress and Migraine

The pathogenesis of migraine is not completely understood, but inflammation and oxidative stress seem to be involved, according to data from an experimental model of the disease. This narrative review summarizes data from studies on oxidative stress markers in migraine patients, case-control association studies on the possible association of candidate genes related to oxidative stress with the risk for migraine, studies showing the presence of oxidative stress in experimental models of migraine, and studies on the efficacy of antioxidant drugs in migraine therapy. Many studies have addressed the value of concentrations of prooxidant and antioxidant substances or the activity of antioxidant enzymes in different tissues (mainly in serum/plasma or in blood cells) as possible biomarkers for migraine, being thiobarbituric acid (TBA) reactive substances (TBARS) such as malonyl dialdehyde acid (MDA) and 4-hydroxynonenal, and nitric oxide (this at least during migraine attacks in patients with migraine with aura (MWA) the most reliable. In addition, the possible usefulness of antioxidant treatment is not well established, although preliminary short-term studies suggest a beneficial action of some of them such as Coenzyme Q10 and riboflavin. Both topics require further prospective, multicenter studies with a long-term follow-up period involving a large number of migraine patients and controls.

The glymphatic system in migraine and other headaches

Glymphatic system is an emerging pathway of removing metabolic waste products and toxic solutes from the brain tissue. It is made of a network of perivascular spaces, filled in cerebrospinal and interstitial fluid, encompassing penetrating and pial vessels and communicating with the subarachnoid space. It is separated from vessels by the blood brain barrier and from brain tissue by the endfeet of the astrocytes rich in aquaporin 4, a membrane protein which controls the water flow along the perivascular space. Animal models and magnetic resonance (MR) studies allowed to characterize the glymphatic system function and determine how its impairment could lead to numerous neurological disorders (e.g. Alzheimer's disease, stroke, sleep disturbances, migraine, idiopathic normal pressure hydrocephalus). This review aims to summarize the role of the glymphatic system in the pathophysiology of migraine in order to provide new ways of approaching to this disease and to its therapy.

AMPK activation attenuates central sensitization in a recurrent nitroglycerin-induced chronic migraine mouse model by promoting microglial M2-type polarization

BACKGROUND

Energy metabolism disorders and neurogenic inflammation play important roles in the central sensitization to chronic migraine (CM). AMP-activated protein kinase (AMPK) is an intracellular energy sensor, and its activation regulates inflammation and reduces neuropathic pain. However, studies on the involvement of AMPK in the regulation of CM are currently lacking. Therefore, this study aimed to explore the mechanism underlying the involvement of AMPK in the central sensitization to CM.

METHODS

Mice with recurrent nitroglycerin (NTG)-induced CM were used to detect the expression of AMPK protein in the trigeminal nucleus caudalis (TNC). Following intraperitoneal injection of the AMPK activator 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR) and inhibitor compound C, the mechanical pain threshold, activity level, and pain-like behaviors in the mice were measured. The expression of calcitonin gene-related peptide (CGRP) and cytokines, M1/M2 microglia, and NF-κB pathway activation were detected after the intervention.

RESULTS

Repeated NTG injections resulted in a gradual decrease in AMPK protein expression, and the negative regulation of AMPK by increased ubiquitin-like plant homeodomain and RING finger domain 1 (UHRF1) expression may counteract AMPK activation by increasing ADP/ATP. AICAR can reduce the hyperalgesia and pain-like behaviors of CM mice, improve the activity of mice, reduce the expression of CGRP, IL-1β, IL-6, and TNF-α in the TNC region, and increase the expression of IL-4 and IL-10. Moreover, AMPK in TNC was mainly located in microglia. AICAR could reduce the expression of inducible NO synthase (iNOS) in M1 microglia and increase the expression of Arginase 1 (Arg1) in M2 microglia by inhibiting the activation of NF-κB pathway.

CONCLUSIONS

AMPK was involved in the central sensitization of CM, and the activation of AMPK reduced neuroinflammation in NTG-induced CM mice. AMPK may provide new insights into interventions for energy metabolism disorders and neurogenic inflammation in migraine.

Migraine Duration as a Potential Amplifier of Obesity

Purpose

Migraine is a complex neurovascular disorder with obesity as a notable risk factor. This study aimed to investigate an under-researched area of the association between migraine duration and body composition.

Patients and Methods

Patients with migraine from a neurology outpatient department were enrolled and were categorized into four groups based on illness duration: 1 year, 1-5 years, 5-10 years, and >10 years. Patient demographics, blood biochemistry, and body composition data were collected and analyzed statistically.

Results

Patients with migraine were predominantly female, with lower education levels, significant work stress, poor sleep, and limited exercise. Longer migraine duration corresponded to increased obesity metrics. Notably, those patients with under 1 year of illness showed elevated blood lipid and liver function levels, whereas those with >10 years showed increased weight, waist circumference, body mass index, and fat content, despite higher physical activity. Significant positive correlation between obesity metrics and migraine duration was seen in patients who had migraine for >1 year.

Conclusion

Our findings indicate that protracted episodes of migraine could amplify obesity tendencies, underscoring the imperative of weight regulation in migraine intervention to diminish ensuing adiposity-associated hazards.

Lipopolysaccharide, VE-cadherin, HMGB1, and HIF-1α levels are elevated in the systemic circulation in chronic migraine patients with medication overuse headache: evidence of leaky gut and inflammation

OBJECTIVE

Medication overuse headache (MOH) was recently shown to be associated with leaky gut in rodents. We aimed to investigate whether chronic migraine (CM) patients with MOH have elevated lipopolysaccharide levels and inflammatory molecules in blood circulation.

MATERIALS AND METHODS

The study included women participants (40 CM patients with NSAID overuse headache, 35 episodic migraine (EM) patients, and 20 healthy non-headache sufferers). Migraine duration, monthly migraine headache days, MigSCog, HADS-D, HADS-A, and HIT-6 scores were recorded. Serum samples were collected to measure circulating LPS, LPS binding protein (LBP), tight junction protein occludin, adherens junction protein vascular endothelial cadherin (VE-cadherin), CGRP, HMGB1, HIF-1α, IL-6, and IL-17 levels.

RESULTS

Serum LPS, VE-Cadherin, CGRP, HIF-1α, and IL-6 levels were significantly higher in the CM + MOH group compared to the EM group and healthy controls while serum LBP and HMGB1 were higher in the CM + MOH group compared to healthy controls. IL-17 and occludin levels were comparable between the three groups. Serum HMGB1 levels in EM patients were higher compared to the control group. Mig-SCog and HIT-6 scores were higher in the CM + MOH group compared to EM patients. HADS-A and HADS-D scores were significantly higher in the CM + MOH group compared to EM patients and healthy controls, and they were also higher in EM patients compared to healthy subjects. LPS levels were correlated with VE-cadherin and occludin levels. The number of monthly migraine headache days was positively correlated with serum LPS, HIF-1α, VE-cadherin, and IL-6 levels, HADS-A, HADS-D, HIT-6, and MigSCog scores.

CONCLUSION

We have evidence for the first time that CM + MOH is associated with elevated serum LPS and LBP levels suggestive of LPS leak into the systemic circulation. Higher levels of nociceptive and/or pro-inflammatory molecules such as HMGB1, HIF-1α, IL-6, and CGRP may play a role in trigeminal sensitization and neurobiology of MOH. Intestinal hyperpermeability and consequent inflammatory response should be considered as a potential contributory factor in patients with MOH.

Increased Prevalence of Headaches and Migraine in Patients with Psoriatic Arthritis and Axial Spondyloarthritis: Insights from an Italian Cohort Study

BACKGROUND

Psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA) are inflammatory diseases with shared genetic backgrounds and clinical comorbidities. Headache, a common global health issue, affects over 50% of adults and encompasses various types, including migraine, tension-type, and cluster headaches. Migraine, the most prevalent, recurrent, and disabling type, is often associated with other medical conditions such as depression, epilepsy, and psoriasis, but little is known about the relationship between autoimmune disease and the risk of migraine.

METHODS

A cross-sectional study was conducted from July to November 2022, enrolling 286 participants, including 216 with PsA, 70 with axSpA, and 87 healthy controls.

RESULTS

Headache prevalence was significantly higher in the PsA (39.81%) and axSpA (45.71%) patients compared to the healthy controls. The prevalence of migraine without aura was also significantly higher in both the PsA (18.52%) and axSpA (28.57%) groups compared to the healthy controls.

CONCLUSIONS

These findings underscore the high burden of headache and migraine in PsA and axSpA participants, highlighting the need for improved management and treatment strategies for these patients.

Association Between Copper Intake and Migraine: a National Cross-sectional Study

Migraine is a common clinical neurological disorder that adversely affects humans and society. The relationship between copper intake and migraine has been less studied and controversial. The purpose of this study was to determine the relationship between copper intake and migraine and to guide dietary interventions. The data for this study were obtained from the National Health and Nutrition Examination Survey (NHANES) database from 1999 to 2004, involving a total of 12,724 participants. The relationship between copper intake and migraine was examined using weighted multivariate logistic regression models, and smooth-fit curves were plotted to explore the relationship. After non-linear relationships were found, recursive algorithms and two-stage linear regression models were used to calculate inflection points. Stratified analyses were also performed to explore population differences. In the model corrected for all covariates, the OR (95% CI) of copper intake with migraine was 1.19 (0.97, 1.46), which was not statistically significant. However, the results of the linear trend test suggested that their relationship might be non-linear. Smooth-fit curves confirmed the non-linear relationship between copper intake and migraine, and an inflection point (0.98 mg/day) was identified. There was no statistical significance before the inflection point, but after the inflection point, copper intake was positively associated with migraine attacks. Stratified analyses showed that this non-linear relationship persisted in females, people under 45 years old, and people with BMI less than 30. In this large cross-sectional study, we found a non-linear correlation between copper intake and migraine.

Serological Biomarkers of Chronic Migraine

PURPOSE OF REVIEW

Chronic migraine (CM) is a chronic form of migraine that differs from episodic migraine (EM) in terms of prevalence, comorbidities, response to treatment, and biomarkers. The aim of this review was to summarize the recent findings on serological biomarkers of CM.

RECENT FINDINGS

Neuronal, inflammatory, and vascular markers have been investigated to assess their diagnostic and prognostic ability and treatment effectiveness. Several markers showed significant alterations according to disease status and treatment response in CM. Calcitonin gene-related peptide (CGRP), glutamate, and adiponectin appear to be the most promising blood biomarkers for CM. Most studies have shown altered ictal and interictal levels of these markers in CM compared with those in EM and controls. Additionally, they showed a significant association with treatment outcomes. Total adiponectin and high-molecular-weight adiponectin levels were less studied as biomarkers of CM than CGRP and glutamate levels but showed promising results. The development of suitable biomarkers could revolutionize the diagnosis and treatment of CM and ultimately decrease the disability and societal costs of the disease.

Glymphatic Dysfunction in Migraine Mice Model

The glymphatic system is important for waste removal in the central nervous system. It removes soluble proteins and metabolic waste under the action of aquaporin-4 (AQP4) at the end of astrocytes. The glymphatic system plays a role in numerous neurological diseases; however, the relationship between migraine and the glymphatic system remains unclear. In this study, we explored the relationship between the glymphatic system and migraine using the nitroglycerin migraine model in C57/BL6mice. The glymphatic influx of cerebrospinal fluid tracer was reduced in mice in the migraine model, accompanied by decreased expression and impaired polarization of AQP4, thereby suggesting glymphatic dysfunction in migraine mice model. Then, further suppression of glymphatic function by TGN-020 (an AQP4 blocker) aggravated the migraine pathological changes in mice. The results indicated that glymphatic dysfunction may aggravate migraine pathology. Therefore, our findings revealed the potential role of the glymphatic system in migraine, providing possible targets for migraine prevention and treatment.

Lipids, lipid-modifying drug target genes and migraine: a Mendelian randomization study

INTRODUCTION

Migraine, a prevalent headache disorder with unclear mechanisms and limited treatments, may be influenced by dyslipidemia and genetic factors. Statins and emerging lipid-modifying agents show potential but lack evidence for migraine management. Mendelian Randomization analysis offers insights into causal relationships and therapeutic targets. This study aims to explore genetically predicted lipid traits, drug targets, and their association with migraine risk.

METHOD

We conducted Mendelian randomization (MR) analyses utilizing genetic variants associated with lipid traits and variants in genes encoding the protein targets of various classes of lipid-lowering drugs. The specific drug classes investigated included HMGCR, PCSK9, NPC1L1, ABCG5/ABCG8, LDLR, LPL, ANGPTL3, APOB, CETP, and APOC3. To determine the effects on migraine risk, we meta-analyzed MR estimates for regional variants using data from two large sample sets. The genetic variants were weighted based on their associations with specific lipid traits, such as low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), Apolipoprotein A1, and Apolipoprotein B. To obtain association weights, we utilized data from lipid genetics consortia. For lipid-modifying drug targets that exhibited suggestive significance, we further employed expression quantitative trait locus (eQTL) data. Additionally, we performed colocalization analysis to assess genetic confounding.

RESULT

The use of genetic proxies for HMGCR inhibition demonstrated a significant association with a decreased risk of migraine in the FinnGen dataset (OR = 0.64, 95% CI: 0.46-0.88, p = 0.0006) and a nearly significant association in the Choquet dataset (OR = 0.78, 95% CI: 0.60-1.01, p = 0.06). When pooling the estimates, the overall effect size showed a reduced risk of migraine (OR = 0.73, 95% CI: 0.60-0.89, p = 0.0016). Similarly, genetic mimicry of LPL enhancement was associated with a lower risk of migraine in the FinnGen dataset (OR = 0.82, 95% CI: 0.69-0.96, p = 0.01) and the Choquet dataset (OR = 0.91, 95% CI: 0.83-0.99, p = 0.03). Pooling the estimates showed a consistent effect size (OR = 0.89, 95% CI: 0.83-0.96, p = 0.002). Sensitivity analyses yielded no statistically significant evidence of bias arising from pleiotropy or genetic confounding.

CONCLUSION

In the study, it was observed that among the 10 lipid-lowering drug targets investigated, LPL and HMGCR showed significant associations with migraine risk. These findings indicate that LPL and HMGCR have the potential to serve as candidate drug targets for the treatment or prevention of migraines.

The status of knowledge on migraines: The role of microglia

Migraines are a considerable social problem and economic burden worldwide. Current acute treatments are based on inhibiting meningeal neurogenic inflammation which has poor results in some patients, whereas the site of action of prophylactic medicines are unknown; therefore, exploring new treatment mechanisms and methods is increasingly needed. Recent evidence suggests that microglia and microglia-mediated neuroinflammation are important in migraine pathogenesis. In the cortical spreading depression (CSD) migraine model, microglia were activated after multiple CSD stimulations, suggesting that microglial activation may be associated with recurrent attacks of migraine with aura. In the nitroglycerin-induced chronic migraine model, the microglial response to extracellular stimuli leads to the activation of surface purine receptors P2X4、P2X7、P2Y12, which mediate signal transduction through intracellular signalling cascades, such as the BDNF/TrkB, NLRP3/IL-1β and RhoA/ROCK signalling pathways, and release inflammatory mediators and cytokines that enhance pain by increasing the excitability of nearby neurons. Inhibition of the expression or function of these microglial receptors and pathways inhibits the abnormal excitability of TNC (trigeminal nucleus caudalis) neurons and intracranial as well as extracranial hyperalgesia in migraine animal models. These findings suggest that microglia may be central in migraine recurrent attacks and a potential target for the treatment of chronic headaches.

History of maternal migraine and its association with preeclampsia: A case-control study in a low-resource setting in Sudan, Africa

BACKGROUND

Previous studies have reported various levels of association between migraine and preeclampsia. However, there are no published data on migraine and its association with preeclampsia in African countries, including Sudan.

METHODS

A case-control study was conducted at Rabak Maternity Hospital in White Nile State, Central Sudan. The cases were pregnant women with preeclampsia, while the controls were healthy pregnant women. All participants were interviewed using questionnaire. The adjusted odds ratio (AOR) and a 95% confidence interval (CI) were calculated in a multivariate regression analysis.

RESULTS

Of 148 pregnant women with preeclampsia, 96 (64.9%) women had mild preeclampsia and 52 (35.1%) women had severe preeclampsia. Of the 148 study participants with preeclampsia, 57 (38.5%) had a history of migraine and 19/296 (6.4%) women in control group had a history of migraine (p < 0.001). Pregnant women with a history of migraine have higher odds of preeclampsia than pregnant women without a history of migraine (AOR = 9.01, 95% CI = 4.81-16.86). A history of preeclampsia, being overweight and obesity were associated with preeclampsia.

CONCLUSION

Our findings are consistent with the findings of previous studies on the association between migraine and preeclampsia. More studies are needed on this topic.

Debate: differences and similarities between tension-type headache and migraine

Tension-type headache (TTH) and migraine are two common primary headaches distinguished by clinical characteristics according to the 3^rd edition of the International Classification of Headache Disorders. Migraine is identified by specific features such as being more prevalent in females, being aggravated by physical activity, certain genetic factors, having photophobia, phonophobia, nausea, vomiting, or aura, and responding to specific drugs. Nonetheless, TTH and migraine share some common characteristics, such as onset occurring in the 20 s, and being triggered by psychological factors like stress, moderate pain severity, and mild nausea in chronic TTH. Both conditions involve the trigeminovascular system in their pathophysiology. However, distinguishing between TTH and migraine in clinical practice, research, and epidemiological studies can be challenging, as there is a lack of specific diagnostic tests and biomarkers. Moreover, both conditions may coexist, further complicating the diagnostic process. This review aims to explore the similarities and differences in the pathophysiology, epidemiology, burden and disability, comorbidities, and responses to pharmacological and non-pharmacological treatments of TTH and migraine. The review also discusses future research directions to address the diagnostic challenges and improve the understanding and management of these conditions.

The Registry for Migraine (REFORM) study: methodology, demographics, and baseline clinical characteristics

BACKGROUND

Erenumab has demonstrated effectiveness for prevention of migraine attacks, but the treatment is costly, and a considerable proportion of patients do not respond to it. The Registry for Migraine study (REFORM) was initiated to discover biomarkers that can predict response to erenumab in patients with migraine. The specific objective was to investigate differences in erenumab efficacy based on clinical information, blood-based biomarkers, structural and functional magnetic resonance imaging (MRI), and response to intravenous infusion of calcitonin gene-related peptide (CGRP). In this first report of the REFORM study, we provide a comprehensive description of the study methodology, and present the baseline characteristics of the study population.

METHODS

The REFORM study was a single-center, prospective, longitudinal cohort study in adults with migraine who were scheduled to receive preventive treatment with erenumab as part of a separate, open-label, single-arm phase IV trial. The study included four periods: a 2-week screening period (Weeks -6 to -5), 4-week baseline period (Week -4 to Day 1), 24-week treatment period (Day 1 to Week 24), and a 24-week follow-up period without treatment (Week 25 to Week 48). Demographic and clinical characteristics were recorded using a semi-structured interview, whilst outcome data were obtained using a headache diary, patient-reported outcomes, blood sampling, brain MRI, and responsiveness to intravenous infusion of CGRP.

RESULTS

The study enrolled 751 participants, with a mean age ± SD of 43.8 ± 12.2 years, of which 88.8% (n = 667) were female. At enrollment, 64.7% (n = 486) were diagnosed with chronic migraine, and 30.2% (n = 227) had history of aura. The mean monthly migraine days (MMDs) was 14.5 ± 7.0. Concomitant preventive medications were used by 48.5% (n = 364) of the participants, and 39.9% (n = 300) had failed ≥ 4 preventive medications.

CONCLUSION

The REFORM study enrolled a population with a high migraine burden and frequent use of concomitant medications. The baseline characteristics were representative of patients with migraine in specialized headache clinics. Future publications will report the results of the investigations presented in this article.

TRIAL REGISTRATION

The study and sub-studies were registered on ClinicalTrials.gov (NCT04592952; NCT04603976; and NCT04674020).

The Association Between Periodontal Disease and Chronic Migraine: A Systematic Review

Migraine is a neurologic illness that produces intense throbbing pain on one side of the head and affects roughly 1 billion people worldwide. Recent research indicates a relationship between periodontitis and chronic migraines. This study aimed to review the association between chronic migraines and periodontitis through a systematic literature review. Four research databases (Google Scholar, PubMed, ProQuest, and SpringerLink) were searched according to PRISMA guidelines to retrieve the studies included in this review. A search strategy was developed to answer the study question with appropriate inclusion and exclusion criteria. Out of 34 published studies, 8 studies were included in this review. Three of the studies were cross-sectional, 3 were case-control, and 2 were clinical report and medical hypothesis papers. Seven of the 8 included studies showed that there is an association between periodontal disease and chronic migraine. The elevated blood levels of some biomarkers such as leptins, ProCalcitonin (proCT), calcitonin gene-related peptides (CGRPs), Pentraxin 3 (PTX3), and Soluble Tumor Necrosis Factor-like Weak Inducer Of Apoptosis (sTWEAK) play a significant role in this association. The limitations include a small sample size, the influence of anti-inflammatory drugs, and a self-reported headache measure that is subject to misclassification bias. This systematic review reveals a supposed correlation between periodontal disease and chronic migraine, as evidenced by various biomarkers and inflammatory mediators. This suggests that periodontal disease could potentially contribute to the development of chronic migraine. However, to further assess the potential benefits of periodontal treatment in patients with chronic migraine, additional longitudinal studies with larger sample sizes and interventional studies are needed.

Experimental and Clinical Investigation of Cytokines in Migraine: A Narrative Review

The role of neuroinflammation in the pathophysiology of migraines is increasingly being recognized, and cytokines, which are important endogenous substances involved in immune and inflammatory responses, have also received attention. This review examines the current literature on neuroinflammation in the pathogenesis of migraine. Elevated TNF-α, IL-1β, and IL-6 levels have been identified in non-invasive mouse models with cortical spreading depolarization (CSD). Various mouse models to induce migraine attack-like symptoms also demonstrated elevated inflammatory cytokines and findings suggesting differences between episodic and chronic migraines and between males and females. While studies on human blood during migraine attacks have reported no change in TNF-α levels and often inconsistent results for IL-1β and IL-6 levels, serial analysis of cytokines in jugular venous blood during migraine attacks revealed consistently increased IL-1β, IL-6, and TNF-α. In a study on the interictal period, researchers reported higher levels of TNF-α and IL-6 compared to controls and no change regarding IL-1β levels. Saliva-based tests suggest that IL-1β might be useful in discriminating against migraine. Patients with migraine may benefit from a cytokine perspective on the pathogenesis of migraine, as there have been several encouraging reports suggesting new therapeutic avenues.

Cytokines in primary headache disorders: a systematic review and meta-analysis

BACKGROUND

The role of inflammation and cytokines in the pathophysiology of primary headache disorders is uncertain. We performed a systematic review and meta-analysis to synthesise the results of studies comparing peripheral blood cytokine levels between patients with migraine, tension-type headache, cluster headache, or new daily persistent headache (NDPH), and healthy controls; and in migraine between the ictal and interictal stages.

METHODS

We searched PubMed/Medline and Embase from inception until July 2022. We included original research studies which measured unstimulated levels of any cytokines in peripheral blood using enzyme-linked immunosorbent assay or similar assay. We assessed risk of bias using the Newcastle-Ottawa Quality Assessment Scale. We used random effects meta-analysis with inverse variance weighted average to calculate standardised mean difference (SMD), 95% confidence intervals, and heterogeneity for each comparison. This study is registered with PROSPERO (registration number CRD42023393363). No funding was received for this study.

RESULTS

Thirty-eight studies, including 1335 patients with migraine (32 studies), 302 with tension-type headache (nine studies), 42 with cluster headache (two studies), and 1225 healthy controls met inclusion criteria. Meta-analysis showed significantly higher interleukin (IL)-6 (SMD 1.07, 95% CI 0.40-1.73, p = 0.002), tumour necrosis factor (TNF)-α (SMD 0.61, 95% CI 0.14-1.09, p = 0.01), and IL-8 (SMD 1.56, 95% CI 0.03-3.09, p = 0.04), in patients with migraine compared to healthy controls, and significantly higher interleukin-1β (IL-1β) (SMD 0.34, 95% CI 0.06-0.62, p = 0.02) during the ictal phase of migraine compared to the interictal phase. Transforming growth factor (TGF)-β (SMD 0.52, 95% CI 0.18-0.86, p = 0.003) and TNF-α (SMD 0.64, 95% CI 0.33-0.96, p = 0.0001) were both higher in patients with tension-type headache than controls.

CONCLUSIONS

The higher levels of the proinflammatory cytokines IL-6, IL-8 and TNF-α in migraine compared to controls, and IL-1β during the ictal stage, suggest a role for inflammation in the pathophysiology of migraine, however prospective studies are required to confirm causality and investigate the mechanisms for the increase in cytokine levels identified. Cytokines may also have a role in tension-type headache. Due a lack of data, no conclusions can be made regarding cluster headache or NDPH.

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.

Lack of Association between Common LAG3/CD4 Variants and Risk of Migraine

Several papers have been published suggesting a probable role of inflammatory factors in the etiopathogenesis of migraine. In this study, we investigated the possible association between common variants in the LAG3/CD4 genes (both genes, which are closely related, encode proteins involved in inflammatory and autoimmune responses) in the risk of migraine in a cohort of Caucasian Spanish participants. For this purpose, the frequencies of CD4 rs1922452, CD4 rs951818, and LAG3 rs870849 genotypes and allelic variants, using a specific TaqMan-based qPCR assay, were assessed in 290 patients diagnosed with migraine and in 300 healthy controls. The relationship of these variables with several clinical features of migraine was also analyzed. The frequencies of the analyzed LAG3/CD4 genotypes did not differ significantly between the two study groups and were not related to the sex, age at onset of migraine, family history of migraine, presence or absence of aura, or the triggering effect of ethanol on migraine episodes. These results suggest a lack of association between common variants in the LAG3/CD4 genes and the risk of developing migraine in the Caucasian Spanish population.

Polymorphisms of the Proinflammatory Cytokine Genes Modulate the Response to NSAIDs but Not to Triptans in Migraine Attacks

Migraine is a common neurovascular disorder characterized by recurrent episodes of headache and associated neurological symptoms. At present, a significant portion of patients do not obtain a satisfactory response to acute pain-relieving therapies, including NSAIDs and triptans. In this context, pharmacogenetics plays a key role in the understanding of such a diverse response. In order to investigate whether functional polymorphisms in proinflammatory cytokine genes (IL-1α, IL-1β, IL-1RN; IL-6 and TNF-α) may influence the response to acute treatment, 313 consecutive patients with episodic migraine without aura were enrolled. Pain relief by administration of NSAIDs or triptans for three consecutive migraine attacks was evaluated. We found a significant association between A allele of the TNF-α promoter (−308 A/G) and a lack of efficacy after NSAID administration (p < 0.01, OR 2.51, 95% CI: 1.33 < OR < 4.75 compared to the G allele). Remaining polymorphisms had no significant effect on pain relief. Our study showed that a functional polymorphism in the TNF-α gene significantly modulates the clinical response to NSAID administration in acute attacks. Patients with higher production of the active cytokine during stress showed a significantly lower anti-migraine effect. Our results further support a role for TNF-α in the pathophysiological mechanisms of migraine attack.