Unbalanced plasma TNF-α and IL-12/IL-10 profile in women with migraine is associated with psychological and physiological outcomes

Neuron-glia crosstalk and inflammatory mediators in migraine pathophysiology

Migraine is a complex neurological disorder with neuroinflammation playing a crucial role in its pathogenesis. This review provides an overview of the neuroinflammation mechanisms in migraine, focusing on both cellular and molecular aspects. At the cellular level, we examine the role of glial cells, including astrocytes, microglia, oligodendrocytes in the central nervous system, and Schwann cells and satellite glial cells in the peripheral nervous system. On the molecular level, we explore the signaling pathways, including IL-1β, TNF-α, IL-6, and non-coding RNAs, that mediate cell interactions or independent actions. Some of the molecular signaling pathways mentioned, such as TNF-α and IL-1β, have been investigated as druggable targets. Recent advancements, such as [11C] PBR28-targeted imaging for visualizing astrocyte activation and single-cell sequencing for exploring cellular heterogeneity, represent breakthroughs in understanding the mechanisms of neuroinflammation in migraine. By considering factors for personalized treatments, estrogen and TRPM8 emerge as promising therapeutic targets regarding sexual dimorphism. These advancements may help bridge the gap between preclinical findings and clinical applications, ultimately leading to more precise and personalized options for migraine patients.

Neuroimmune interactions in the development and chronification of migraine headache

Migraine is highly prevalent and debilitating. The persistent headaches in this condition are thought to arise from the activation and sensitization of the trigeminovascular pathway. Both clinical and animal model studies have suggested that neuroimmune interactions contribute to the pathophysiology of migraine headache. In this review, we first summarize the findings from human studies implicating the dysregulation of the immune system in migraine, including genetic analyses, measurement of circulatory factors, and neuroimaging data. We next discuss recent advances from rodent studies aimed at elucidating the neuroimmune interactions that manifest at various levels of the trigeminovascular pathway and lead to the recruitment of innate and adaptive immune cells as well as immunocompetent glial cells. These cells reciprocally modulate neuronal activity via multiple pro- and anti-inflammatory mediators, thereby regulating peripheral and central sensitization. Throughout the discussions, we highlight the potential clinical and translational implications of the findings.

Study on the involvement of microglial S100A8 in neuroinflammation and microglia activation during migraine attacks

BACKGROUND

Microglia is the primary source of inflammatory factors during migraine attacks. This study aims to investigate the role of microglia related genes (MRGs) in migraine attacks.

METHODS

The RNA sequencing results of migraineurs and the panglaodb database were used to obtain differentially expressed genes (DEGs) in migraine related to microglia. A migraine rat model was established for validating and localizing of the MRGs, and subsequent screening for target genes was conducted. A shRNA was designed to interference the expression of target genes and administered into the trigeminal ganglion (TG) of rats. Pain sensitivity in rats was evaluated via the hot water tail-flick (HWTF) and formalin-induced pain (FIP) experiments. ELISA was used to quantify the levels of inflammatory cytokines and CGRP. WB and immunofluorescence assays were applied to detect the activation of microglia.

RESULTS

A total of five DEGs in migraine related to microglia were obtained from RNA sequencing and panglaodb database. Animal experiments showed that these genes expression were heightened in the TG and medulla oblongata (MO) of migraine rats. The gene S100A8 co-localized with microglia in both TG and MO. The HWTF and FIP experiments demonstrated that interference with S100A8 alleviated the sense of pain in migraine rats. Moreover, the levels of TNFα, IL-1β, IL-6, and CGRP in the TG and MO of rats in the model rats were increased, and the expression of microglia markers IBA-1, M1 polarization markers CD86 and iNOS was upregulated. Significantly, interference with S100A8 reversed these indicators.

CONCLUSION

Interference with S100A8 in microglia increased the pain threshold during migraine attacks, and inhibited neuroinflammation and microglia activation.

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.

Causality between multiple autoimmune disorders and migraine and its subtypes: a two-sample Mendelian randomization study

Introduction

Several studies have reported associations between various autoimmune diseases and migraine. Using Mendelian randomization (MR), this study aimed to evaluate the interplay between autoimmune diseases and migraine.

Methods

Here, instrumental variables, exposure factors, and outcome factors for 10 common autoimmune diseases and migraine and its subtypes were screened. This screening utilized comprehensive statistics from Europe's largest genome-wide association study and performed reverse MR analysis on positive results. The causality between autoimmune diseases and migraine was comprehensively assessed using multiple analytical methods. Additionally, sensitivity analyses, such as the horizontal diversity heterogeneity and leave-one-out method, were performed.

Results

Random-effects inverse variance weighting analysis revealed a causal correlation between autoimmune hyperthyroidism and migraine (p = 0.0002), and this association was consistent across both migraine with aura (MA; p = 0.006) and migraine without aura (MO; p = 0.017). In addition, there was a positive causal association between systemic lupus erythematosus (SLE) and MA (p = 0.001) and between hypothyroidism and MO (p = 0.038). There is insufficient evidence to substantiate a causal link between outcomes and other autoimmune-related disorders, and reverse MR results did not reveal a causal relationship between migraines and these autoimmune disorders. The validity of the results was demonstrated by a sensitivity analysis; horizontal pleiotropy and heterogeneity were not observed.

Discussion

This study observed a positive genetic association between autoimmune hyperthyroidism and migraines. In addition, SLE positively affects MA, and hypothyroidism contributes to the incidence of MO. These results have great significance for future research and prevention of 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.

Altered immunity in migraine: a comprehensive scoping review

BACKGROUND

The pathogenesis of migraine remains unclear; however, a large body of evidence supports the hypothesis that immunological mechanisms play a key role. Therefore, we aimed to review current studies on altered immunity in individuals with migraine during and outside attacks.

METHODS

We searched the PubMed database to investigate immunological changes in patients with migraine. We then added other relevant articles on altered immunity in migraine to our search.

RESULTS

Database screening identified 1,102 articles, of which 41 were selected. We added another 104 relevant articles. We found studies reporting elevated interictal levels of some proinflammatory cytokines, including IL-6 and TNF-α. Anti-inflammatory cytokines showed various findings, such as increased TGF-β and decreased IL-10. Other changes in humoral immunity included increased levels of chemokines, adhesion molecules, and matrix metalloproteinases; activation of the complement system; and increased IgM and IgA. Changes in cellular immunity included an increase in T helper cells, decreased cytotoxic T cells, decreased regulatory T cells, and an increase in a subset of natural killer cells. A significant comorbidity of autoimmune and allergic diseases with migraine was observed.

CONCLUSIONS

Our review summarizes the findings regarding altered humoral and cellular immunological findings in human migraine. We highlight the possible involvement of immunological mechanisms in the pathogenesis of migraine. However, further studies are needed to expand our knowledge of the exact role of immunological mechanisms in migraine pathogenesis.

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.

Study on the correlation between IL-12p70, IL-17A and migraine in children

Objective

To compare the serum levels of 12 cytokines in migraine group, encephalitis with headache symptoms group, pneumonia without headache symptoms group and migraine subgroups to explore the cytokines associated with migraine in children and their levels.

Methods

A total of 44 children with migraine, 27 children in the encephalitis group with headache symptoms and 44 children in the pneumonia group without headache symptoms were selected from January 2022 to August 2023 in Hebei Children's Hospital. They were all tested for serum cytokines by immunofluorescence assay. The migraine group was further divided into subgroups according to different age, gender, course of disease, and presence of coinfection. The differences of serum cytokine levels among the above groups were compared, and the correlation analysis was carried out.

Results

Except IL-5, there were no significant differences in the expression levels of other 11 inflammatory cytokines between migraine subgroups. Compared with encephalitis with headache symptoms group and pneumonia without headache symptoms group the serum levels of IL-4, TNF-α, IL-17A, and IL-12p70 were higher in migraine group than in pneumonia group, and the levels of IL-12p70 were higher than those in encephalitis group (p < 0.05). An increase in serum IL-12p70 (OR = 1.267, 95%CI 1.054-1.523, p = 0.012) and IL-17A (OR = 1.066, 95%CI 1.016-1.119, p = 0.010) levels had a significant effect on migraine.

Conclusion

Elevated serum levels of IL-12p70 and IL-17A may increase the risk of migraine in children, which has certain diagnostic and predictive value.

Role of TNF-α in the Pathogenesis of Migraine

Background

Neurogenic neuroinflammation has a wide role in migraine pathogenesis including the transition from episodic migraine to chronic one. The seed molecule of neurogenic neuroinflammation, i.e., the TNF-α proinflammatory molecule, has gathered a lot of attention. This pleiotropic cytokine is a classical component of inflammatory soup, secreted by the microglial cell, and promotes a wide range of inflammatory reactions.

Aim

In this review, we aimed to provide a culminating and comprehending glimpse into the TNF-α in association with the migraine.

Method

A systematic literature survey method with a mixture of keywords was utilized to grasp the different elements that represent the association between TNF-α and migraine. Discussion. Highlighted the probable involvement of the TNF-α with migraine, the complexity of the matter such as activation of NF-KB signaling cascade, autoactivation, sensitization, and increased likelihood of transition cannot be neglected. Being TNF-α as a core node, it becomes the factor for linking diseases such as chronic inflammatory disorders, including COVID-19, and also interaction with other genes to develop severe conditions.

Conclusion

To this end, TNF-α plays a critical role in chronification, and inhibiting its signaling would likely be a crucial strategy for migraine therapy.

Aryl hydrocarbon receptors improve migraine-like pain behaviors in rats through the regulation of regulatory T cell/T-helper 17 cell-related homeostasis

OBJECTIVE

To investigate the effect of the aryl hydrocarbon receptor (AHR)/regulatory T cell (Treg)/T-helper 17 (Th17) cell pathway on the pathogenesis of migraine.

BACKGROUND

Migraine is a disabling neurovascular disease that imposes an enormous burden on both individuals and society. The pathophysiological mechanisms of migraine remain controversial. Recent studies have suggested that immune dysfunction may be involved in the pathogenesis of migraine. The AHR, a receptor expressed on most immune cells, has been implicated in the occurrence of many autoimmune diseases; however, whether it is involved in the pathogenesis of migraine is unclear.

METHODS

A chronic migraine rat model was established through repeated intraperitoneal injection of nitroglycerin (NTG). The mechanical and thermal pain thresholds were assessed using von Frey filaments and radiant heat. Next, the protein expression levels of AHR in the trigeminal nucleus caudalis (TNC) region of chronic migraine (CM)-like rats were quantified and the changes in Treg/Th17-related transcription factors and inflammatory factors in the TNC were explored. To determine the role of AHR in CM, we examined the effects of the AHR agonist 2-(1'-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE), and AHR antagonist CH-223191 on pain behavior, c-Fos, calcitonin gene-related peptide (CGRP), AHR, and Treg/Th17-related factor expression in CM-like rats.

RESULTS

Repeated administration of NTG significantly enhanced nociceptive hypersensitivity and increased expression of c-Fos and CGRP in rats, while AHR was significantly decreased in the TNC. In addition, the expression of the transcription factor forkhead box protein P3 and the signal transducer and activator of transcription 5 decreased significantly. In contrast, the expression of the transcription factor retinoic acid receptor-related orphan receptor γ t and signal transducer and activator of transcription 3 were significantly increased. Moreover, the mRNA level of transforming growth factor beta-1 was decreased, while that of interleukin (IL)-10 and IL-22 was increased in the TNC. The AHR agonist ITE alleviated migraine-like pain behaviors in rats, activated the AHR signaling pathway, and improved the imbalance of Treg/Th17-related transcription factors and inflammatory factors. Conversely, the AHR antagonist CH-223191 did not alleviate migraine-like pain behaviors in rats; and even exacerbated them.

CONCLUSIONS

The AHR participates in the development of CM by regulating Treg/Th17-related homeostasis. Therefore, treatments targeting the AHR/Treg/Th17 signaling pathway could be new effective interventions for CM treatment.

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.

Microglia polarization in nociplastic pain: mechanisms and perspectives

Nociplastic pain is the third classification of pain as described by the International Association for the Study of Pain (IASP), in addition to the neuropathic and nociceptive pain classes. The main pathophysiological mechanism for developing nociplastic pain is central sensitization (CS) in which pain amplification and hypersensitivity occur. Fibromyalgia is the prototypical nociplastic pain disorder, characterized by allodynia and hyperalgesia. Much scientific data suggest that classical activation of microglia in the spinal cord mediates neuroinflammation which plays an essential role in developing CS. In this review article, we discuss the impact of microglia activation and M1/M2 polarization on developing neuroinflammation and nociplastic pain, besides the molecular mechanisms engaged in this process. In addition, we mention the impact of microglial modulators on M1/M2 microglial polarization that offers a novel therapeutic alternative for the management of nociplastic pain disorders. Illustrating the mechanisms underlying microglia activation in central sensitization and nociplastic pain. LPS lipopolysaccharide, TNF-α tumor necrosis factor-α, INF-γ Interferon gamma, ATP adenosine triphosphate, 49 P2Y12/13R purinergic P2Y 12/13 receptor, P2X4/7R purinergic P2X 4/7 receptor, SP Substance P, NK-1R Neurokinin 1 receptor, CCL2 CC motif ligand 2, CCR2 CC motif ligand 2 receptor, CSF-1 colony-stimulating factor 1, CSF-1R colony-stimulating factor 1 receptor, CX3CL1 CX3C motif ligand 1, CX3XR1 CX3C motif ligand 1 receptor, TLR toll-like receptor, MAPK mitogen-activated protein kinases, JNK jun N-terminal kinase, ERK extracellular signal-regulated kinase, iNOS Inducible nitric oxide synthase, IL-1β interleukin-1β, IL-6 interleukin-6, BDNF brain-derived neurotrophic factor, GABA γ-Aminobutyric acid, GABAR γ-Aminobutyric acid receptor, NMDAR N-methyl-D-aspartate receptor, AMPAR α-amino-3-hydroxy-5-methyl-4-isoxazolepropi-onic acid receptor, IL-4 interleukin-4, IL-13 interleukin-13, IL-10 interleukin-10, Arg-1 Arginase 1, FGF fibroblast growth factor, GDNF glial cell-derived neurotrophic factor, IGF-1 insulin-like growth factor-1, NGF nerve growth factor, CD Cluster of differentiation.

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.

Electroacupuncture at Fengchi(GB20) and Yanglingquan(GB34) Ameliorates Paralgesia through Microglia-Mediated Neuroinflammation in a Rat Model of Migraine

Background: Multiple studies have suggested that paralgesia (hyperalgesia and cutaneous allodynia) in migraine reflects the activation and sensitisation of the trigeminovascular system (TGVS). In particular, it reflects the second-order and higher nerve centre sensitisation, which is caused and maintained by neuroinflammation. Microglia activation leads to the release of proinflammatory cytokines involved in inflammatory responses. Accumulating evidence indicates that electroacupuncture (EA) is effective in ameliorating paralgesia, but the underlying mechanisms of EA in migraine attacks caused by microglia and microglia-mediated inflammatory responses are still unclear. The purpose of this study was to explore whether EA could ameliorate the dysregulation of pain sensation by suppressing microglial activation and the resulting neuroinflammatory response, and to evaluate whether this response was regulated by Toll-like receptor 4 (TLR4)/nuclear factor-kappa B(NF-κB) in the trigeminal nucleus caudalis (TNC) in a rat model of migraine. Methods: Repeated Inflammatory Soup (IS) was infused into the dura for seven sessions to establish a recurrent migraine-like rat model, and EA treatment was administered at Fengchi (GB20) and Yanglingquan (GB34) after daily IS infusion. Facial mechanical withdrawal thresholds were measured to evaluate the change in pain perception, and plasma samples and the TNC tissues of rats were collected to examine the changes in calcitonin gene-related peptide (CGRP), the Ibal-1-labelled microglial activation, and the resulting inflammatory response, including interleukin-1β (IL-1β), tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6), and their regulatory molecules TLR4/NF-κB, via enzyme-linked immunosorbent assay (ELISA), real-time polymerase chain reaction (RT-PCR), immunohistochemistry (IHC) and Western blot analysis. Results: Repeated IS injections into the dura induced facial mechanical paralgesia, which is the manifestation of migraine attacks, and increased the expression of CGRP, Ibal-1, microglial mediated inflammatory cytokines (IL-1β, TNF-α, IL-6), and regulatory molecules TLR4/NF-κB. EA at GB20/34 significantly attenuated repetitive IS-induced pain hypersensitivity. This effect was consistent with decreased levels of CGRP and inflammatory cytokines in the plasma and the TNC via the inhibition of microglia activation, and this response may be regulated by TLR4/NF-κB. Conclusions: EA ameliorated paralgesia in repetitive IS-induced migraine-like rats, which was mainly mediated by a reduction in microglial activation and microglial-mediated inflammatory responses that could be regulated by TLR4/NF-κB.

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.

Migraine as an inflammatory disorder with microglial activation as a prime candidate

BACKGROUND

The lower threshold of neuronal hyperexcitability has been correlated with migraines for decades but as technology has progressed, it has now become conceivable to learn more about the migraine disease. Apart from the "cortical spreading depression" and "activation of the trigeminovascular system", inflammation has been increasingly recognized as a possible pathogenic process that may have the possibility to regulate the disease severity. Microglial cells, the prime candidate of the innate immune cells of central nervous tissue, has been associated with numerous diseases; including cancer, neurodegenerative disorders, and inflammatory disorders.

AIM

In this review, we have attempted to link the dot of various microglial activation signaling pathways to enlighten the correlation between microglial involvement and the progression of migraine conditions.

METHOD

A structured survey of research articles and review of the literature was done in the electronic databases of Google Scholar, PubMed, Springer, and Elsevier until 31 December 2021.

RESULT & CONCLUSION

Of 1136 articles found initially and screening of 1047 records, 47 studies were included for the final review. This review concluded that inflammation and microglial overexpression as the prime candidate, plays an important role in the modulation of migraine and are responsible for the progression toward chronification. Therefore, this increases the possibility of preventing migraine development and chronification by blocking microglia overexpression.

Examining the correlation between salivary cytokine concentrations and CRP in people experiencing social-cognitive stress

OBJECTIVES

The study aims to determine the relationship of migraine and chronic tension-type headache (TTHs) with alterations in the salivary markers of inflammation .

METHODS

The prospective study involved 75 patients . The concentrations of inflammatory markers (CRP, IL-1 β, and IL-6) in migraine and chronic TTH patients were determined in distinct time points: headache-free period (interictal period), during headache (ictal period), day after headache attack. The STAI-Y (State Trait Anxiety Inventory - Y) and BDI (Beck Depression Inventory) questionnaires were used to measure the level of anxiety and depression in the interictal and ictal periods.

RESULTS

The interictal levels of CRP, IL1-β, and IL-6 were significantly higher in headache groups compared to healthy controls (p < 0.001). Differences in the ictal concentrations were even stronger. Twenty-four hours after headache attack, patients with migraine and chronic TTH experienced a decrease in CRP, IL1-β, and IL-6 levels; yet, those levels were still higher compared with the interictal ones. The repeated analysis of variance revealed no significant statistical differences in CRP, IL-β, and IL-6 levels between the migraine and TTH groups over time (p > 0.05). Statistically higher levels of anxiety and depression were seen in unhealthy groups (p < 0.01).

CONCLUSIONS

The relationship of CRP, IL1-β, and IL-6 concentrations with migraine and chronic TTH has been established. No statistically significant differences were found in the dynamics between migraine and chronic TTH groups. There was a direct correlation of migraine and chronic TTH with anxiety and depression.

What is the efficacy of aerobic exercise versus strength training in the treatment of migraine? A systematic review and network meta-analysis of clinical trials

Background

Multiple clinical trials with different exercise protocols have demonstrated efficacy in the management of migraine. However, there is no head-to-head comparison of efficacy between the different exercise interventions.

Methods

A systematic review and network meta-analysis was performed involving all clinical trials which determined the efficacy of exercise interventions in reducing the frequency of monthly migraine. Medical journal search engines included Web of Science, PubMed, and Scopus spanning all previous years up to July 30, 2022. Both aerobic and strength/resistance training protocols were included. The mean difference (MD, 95% confidence interval) in monthly migraine frequency from baseline to end-of-intervention between the active and control arms was used as an outcome measure. Efficacy evidence from direct and indirect comparisons was combined by conducting a random effects model network meta-analysis. The efficacy of the three exercise protocols was compared, i.e., moderate-intensity aerobic exercise, high-intensity aerobic exercise, and strength/resistance training. Studies that compared the efficacy of migraine medications (topiramate, amitriptyline) to exercise were included. Additionally, the risk of bias in all included studies was assessed by using the Cochrane Risk of Bias version 2 (RoB2).

Results

There were 21 published clinical trials that involved a total of 1195 migraine patients with a mean age of 35 years and a female-to-male ratio of 6.7. There were 27 pairwise comparisons and 8 indirect comparisons. The rank of the interventions was as follows: strength training (MD = -3.55 [− 6.15, − 0.95]), high-intensity aerobic exercise (-3.13 [-5.28, -0.97]), moderate-intensity aerobic exercise (-2.18 [-3.25, -1.11]), topiramate (-0.98 [-4.16, 2.20]), placebo, amitriptyline (3.82 [− 1.03, 8.68]). The RoB2 assessment showed that 85% of the included studies demonstrated low risk of bias, while 15% indicated high risk of bias for intention-to-treat analysis. Sources of high risk of bias include randomization process and handling of missing outcome data.

Conclusion

Strength training exercise regimens demonstrated the highest efficacy in reducing migraine burden, followed by high-intensity aerobic exercise.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-022-01503-y.

Normalization of Neuroinflammation: A New Strategy for Treatment of Persistent Pain and Memory/Emotional Deficits in Chronic Pain

Chronic pain, which affects around 1/3 of the world population and is often comorbid with memory deficit and mood depression, is a leading source of suffering and disability. Studies in past decades have shown that hyperexcitability of primary sensory neurons resulting from abnormal expression of ion channels and central sensitization mediated pathological synaptic plasticity, such as long-term potentiation in spinal dorsal horn, underlie the persistent pain. The memory/emotional deficits are associated with impaired synaptic connectivity in hippocampus. Dysregulation of numerous endogenous proteins including receptors and intracellular signaling molecules is involved in the pathological processes. However, increasing knowledge contributes little to clinical treatment. Emerging evidence has demonstrated that the neuroinflammation, characterized by overproduction of pro-inflammatory cytokines and glial activation, is reliably detected in humans and animals with chronic pain, and is sufficient to induce persistent pain and memory/emotional deficits. The abnormal expression of ion channels and pathological synaptic plasticity in spinal dorsal horn and in hippocampus are resulting from neuroinflammation. The neuroinflammation is initiated and maintained by the interactions of circulating monocytes, glial cells and neurons. Obviously, unlike infectious diseases and cancer, which are caused by pathogens or malignant cells, chronic pain is resulting from alterations of cells and molecules which have numerous physiological functions. Therefore, normalization (counterbalance) but not simple inhibition of the neuroinflammation is the right strategy for treating neuronal disorders. Currently, no such agent is available in clinic. While experimental studies have demonstrated that intracellular Mg²⁺ deficiency is a common feature of chronic pain in animal models and supplement Mg²⁺ are capable of normalizing the neuroinflammation, activation of upregulated proteins that promote recovery, such as translocator protein (18k Da) or liver X receptors, has a similar effect. In this article, relevant experimental and clinical evidence is reviewed and discussed.

Network Pharmacology-Based Investigation on Therapeutic Mechanisms of the Angelica dahurica Radix and Ligusticum chuanxiong Rhizoma Herb Pair for Anti-Migraine Effect

Migraines are a common neurological disorder characterized by desperate throbbing unilateral headaches and are related to phonophobia, photophobia, nausea, and vomiting. The Angelica dahurica Radix and Ligusticum chuanxiong Rhizoma herb pair (ALHP) has been used to treat migraines for centuries in traditional Chinese medicine (TCM). However, the physiological mechanisms of migraine treatment have not yet been elucidated. In this study, a total of 50 hub targets related to the effect of 28 bioactive compounds in ALHP on anti-migraine were obtained through network pharmacology analysis. GO and KEGG analyses of the hub targets demonstrated that ALHP treatment of migraines significantly involved the G-protein-coupled receptor signaling pathway, chemical synaptic transmission, inflammatory response, and other biological processes. According to the degree of gene targets in the network, ACE, SLC3A6, NR3CI, MAPK1, PTGS2, PIK3CA, RELA, GRIN1, GRM5, IL1B, and DRD2 were found to be the core gene targets. The docking results showed a high affinity for docked conformations between compounds and predicted targets. The results of this study suggest that ALHP could treat migraines by regulating immunological functions, diminishing inflammation, and improving immunity through different physiological pathways, which contributes to the scientific base for more in-depth research as well as for a more widespread clinical application of ALHP.

The role of cytokines in migraine: A systematic review

BACKGROUND

Cytokines are important endogenous substances that are involved in immune and inflammatory responses. Neurogenic inflammation has been proposed to play a role in migraine involving altered cytokine levels. Therefore, we aimed to provide a systematic review on the current knowledge on cytokine levels in migraine patients during and outside attacks.

METHODS

Databases of PubMed and Embase were systematically searched for studies investigating cytokine levels in migraine patients during and outside attacks.

RESULTS

Screening yielded identification of 45 articles investigating 18 cytokines in total. We found that the interictal level of the anti-inflammatory cytokine, interleukin 10, was decreased, while the level of transforming growth factor beta 1 was increased in migraine patients compared to controls. Levels of pro-inflammatory cytokines, tumor necrosis factor α and interleukin 6, were increased outside attacks compared to controls. Ictal levels of cytokines were unchanged or varying compared to the interictal state in migraine patients. Three studies reported dynamic cytokines levels during the course of an attack.

CONCLUSION

The findings of the current review underline a possible involvement of cytokines in the proposed inflammatory mechanisms of migraine. However, future studies are needed to expand our knowledge of the exact role of cytokines in the migraine pathophysiology with focus on cytokines TNF-α, IL-1ß, IL-6 and IL-10 while applying refined methodology.

Unpredictable Sound Stress Model Causes Migraine-Like Behaviors in Mice With Sexual Dimorphism

Migraine represents one of the major causes of disability worldwide and is more prevalent in women; it is also related to anxiety symptoms. Stress, such as sound stress, is a frequently reported trigger in migraine patients, but the underlying mechanisms are not fully understood. However, it is known that patients with migraine have higher levels of plasma inflammatory cytokines and calcitonin gene-related peptide (CGRP). Stress mediated by unpredictable sound is already used as a model of painful sensitization, but migraine-like behaviors and sexual dimorphism have not yet been evaluated. This study characterized nociception and anxiety-related symptoms after the induction of sound stress in mice. C57BL/6 mice (20-30 g) were exposed to unpredictable sound stress for 3 days, nonconsecutive days. We observed enhanced plasma corticosterone levels on day 1 after stress induction. First, 7 days after the last stress session, mice developed hind paw and periorbital mechanical allodynia, grimacing pain behavior, anxiety-like symptoms, and reduced exploratory behavior. The nociceptive and behavioral alterations detected in this model were mostly shown in female stressed mice at day 7 post-stress. In addition, on day 7 post-stress nociception, these behaviors were consistently abolished by the CGRP receptor antagonist olcegepant (BIBN4096BS, 100 mg/kg by intraperitoneal route) in female and male stressed mice. We also demonstrated an increase in interleukine-6 (IL-6), tumor necrosis factor (TNF-α), and CGRP levels in stressed mice plasma, with female mice showing higher levels compared to male mice. This stress paradigm allows further preclinical investigation of mechanisms contributing to migraine-inducing pain.

The role of the meningeal lymphatic system in local meningeal inflammation and trigeminal nociception

A system of lymphatic vessels has been recently characterized in the meninges, with a postulated role in ‘cleaning’ the brain via cerebral fluid drainage. As meninges are the origin site of migraine pain, we hypothesized that malfunctioning of the lymphatic system should affect the local trigeminal nociception. To test this hypothesis, we studied nociceptive and inflammatory mechanisms in the hemiskull preparations (containing the meninges) of K14-VEGFR3-Ig (K14) mice lacking the meningeal lymphatic system. We recorded the spiking activity of meningeal afferents and estimated the local mast cells population, calcitonin gene-related peptide (CGRP) and cytokine levels as well as the dural trigeminal innervation in freshly-isolated hemiskull preparations from K14-VEGFR3-Ig (K14) or wild type C57BL/6 mice (WT). Spiking activity data have been confirmed in an acquired model of meningeal lymphatic dysfunction (AAV-mVEGFR3(1–4)Ig induced lymphatic ablation). We found that levels of the pro-inflammatory cytokine IL12-p70 and CGRP, implicated in migraine, were reduced in the meninges of K14 mice, while the levels of the mast cell activator MCP-1 were increased. The other migraine-related pro-inflammatory cytokines (basal and stimulated), did not differ between the two genotypes. The patterns of trigeminal innervation in meninges remained unchanged and we did not observe alterations in basal or ATP-induced nociceptive firing in the meningeal afferents associated with meningeal lymphatic dysfunction. In summary, the lack of meningeal lymphatic system is associated with a new balance between pro- and anti-migraine mediators but does not directly trigger meningeal nociceptive state.

Genetic analyses identify pleiotropy and causality for blood proteins and highlight Wnt/β-catenin signalling in migraine

Migraine is a common complex disorder with a significant polygenic SNP heritability (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${h}_{{SNP}}^{2}$$\end{document}hSNP2). Here we utilise genome-wide association study (GWAS) summary statistics to study pleiotropy between blood proteins and migraine under the polygenic model. We estimate \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${h}_{{SNP}}^{2}$$\end{document}hSNP2 for 4625 blood protein GWASs and identify 325 unique proteins with a significant \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${h}_{{SNP}}^{2}$$\end{document}hSNP2 for use in subsequent genetic analyses. Pleiotropy analyses link 58 blood proteins to migraine risk at genome-wide, gene and/or single-nucleotide polymorphism levels—suggesting shared genetic influences or causal relationships. Notably, the identified proteins are largely distinct from migraine GWAS loci. We show that higher levels of DKK1 and PDGFB, and lower levels of FARS2, GSTA4 and CHIC2 proteins have a significant causal effect on migraine. The risk-increasing effect of DKK1 is particularly interesting—indicating a role for downregulation of β-catenin-dependent Wnt signalling in migraine risk, suggesting Wnt activators that restore Wnt/β-catenin signalling in brain could represent therapeutic tools against migraine.

Understanding of the causes and treatment of migraine is incomplete. Here, the authors detect pleiotropic genetic effects and causal relationships between migraine and 58 proteins that are largely distinct from migraine-associated loci identified by GWAS.

Wen Dan Tang: A Potential Jing Fang Decoction for Headache Disorders?

BACKGROUND

Chinese herbal medicine is considered relatively safe, inexpensive, and easily accessible. Wen Dan Tang (WDT), a Jing Fang ancient classical Chinese herbal formula with a broad indication profile has been used for several centuries in China to treat various illnesses.

QUESTION

Are there evidence-based clinical trials that show that WDT has a significant impact on the treatment of various diseases, especially in patients with migraine and tension-type headaches (TTH)?

METHODS

This study is based on an online database search using PubMed, Medline, Cochrane Library, AcuTrials, Embase, Semantic Scholar, Jstor, internet research, and review of ancient and modern Chinese medical textbooks regarding WDT and its compounds.

RESULTS

There were no studies on WDT in migraine and TTH; therefore, this work gathers and describes data for every single compound in the formula.

CONCLUSION

This study suggests that the bioactive compounds found in WDT composition show potential in treating patients with neurological, psychiatric disorders, cardiovascular diseases, metabolic syndrome, and digestive disorders. Some coherence between WDT in headache reduction and improvements in the quality of life in patients with migraines and TTH could be evaluated, showing positive results of WDT in these patients.

C4BPA: A Novel Co-Regulator of Immunity and Fat Metabolism in the Bovine Mammary Epithelial Cells

The C4b binding protein alpha (C4BPA) chain primarily engages in critical inflammatory and coagulation processes. The previous transcriptomic analysis showed that C4BPA is a differentially expressed gene in lower and higher fat content mammary gland cell lines from Chinese Holstein. This study aimed to investigate the effects of C4BPA on the inflammation and milk fat synthesis in bMECs by C4BPA knockdown and overexpression. The results highlighted that knockdown of C4BPA in bMECs could suppress the mRNA and protein expression of IL-6, IL-8, IL-12, and the TLR-4/NF-κB pathway-related genes and promote the expression of complement and coagulation cascade pathways related genes as well as TNF-α. Moreover, knockdown of C4BPA expression in bMECs reduced the content of triglyceride (TG) and cholesterol (CHOL) in bMECs, increased NEFA content, reduced mRNA and protein expression of ACSL1 and PPARA, and increased the mRNA and protein expression of ELOVL6, FADS1, and LPL. The bMECs, with the overexpression of C4BPA, showed the enhanced expression of TLR-4/NF-κB linked genes, IL-6, IL-8, IL-12, and mRNA and protein level while reduced mRNA expression of TNF-α, compliment, and coagulation cascade related genes was observed. In bMECs, overexpression of C4BPA enhanced the content of TG and CHOL while reducing NEFA and stimulated the mRNA and protein expression of ACSL1, PPARA, and PPARG genes while inhibiting the mRNA and protein expression of FADS1 and LPL genes. Our results show that C4BPA not only regulates the lipid metabolism through the PPAR signaling pathway in bMECs but also contributes to the inflammatory response through TLR-4/NF-κB and the complement and coagulation cascade pathways. This study, for the first time, provides the primary basis for understanding the role of C4BPA in immunity and fat metabolism, which enables the researchers for innovative direction to investigate genes associated with fat metabolism and immunity. This study also advocates that the breeders must pay attention to such type of genes with multiple functions during animal breeding.

Immunological findings in patients with migraine and other primary headaches: a narrative review

Experimental findings suggest an involvement of neuroinflammatory mechanisms in the pathophysiology of migraine. Specifically, preclinical models of migraine have emphasized the role of neuroinflammation following the activation of the trigeminal pathway at several peripheral and central sites including dural vessels, the trigeminal ganglion, and the trigeminal nucleus caudalis. The evidence of an induction of inflammatory events in migraine pathophysiological mechanisms has prompted researchers to investigate the human leukocyte antigen (HLA) phenotypes as well as cytokine genetic polymorphisms in order to verify their potential relationship with migraine risk and severity. Furthermore, the role of neuroinflammation in migraine seems to be supported by evidence of an increase in pro-inflammatory cytokines, both ictally and interictally, together with the prevalence of Th1 lymphocytes and a reduction in regulatory lymphocyte subsets in peripheral blood of migraineurs. Cytokine profiles of cluster headache (CH) patients and those of tension-type headache patients further suggest an immunological dysregulation in the pathophysiology of these primary headaches, although evidence is weaker than for migraine. The present review summarizes available findings to date from genetic and biomarker studies that have explored the role of inflammation in primary headaches.

Headache and immunological/autoimmune disorders: a comprehensive review of available epidemiological evidence with insights on potential underlying mechanisms

Several lines of evidence support a role of the immune system in headache pathogenesis, with particular regard to migraine. Firstly, alterations in cytokine profile and in lymphocyte subsets have been reported in headache patients. Secondly, several genetic and environmental pathogenic factors seem to be frequently shared by headache and immunological/autoimmune diseases. Accordingly, immunological alterations in primary headaches, in particular in migraine, have been suggested to predispose some patients to the development of immunological and autoimmune diseases. On the other hand, pathogenic mechanisms underlying autoimmune disorders, in some cases, seem to favour the onset of headache. Therefore, an association between headache and immunological/autoimmune disorders has been thoroughly investigated in the last years. The knowledge of this possible association may have relevant implications in the clinical practice when deciding diagnostic and therapeutic approaches. The present review summarizes findings to date regarding the plausible relationship between headache and immunological/autoimmune disorders, starting from a description of immunological alteration of primary headaches, and moving onward to the evidence supporting a potential link between headache and each specific autoimmune/immunological disease.

Clinical and Cytokine Profile in Patients with Early and Late Onset Meniere Disease

BACKGROUND

Meniere disease (MD) is an inner ear disorder associated with comorbidities such as autoimmune diseases or migraine. This study describes clinical and cytokine profiles in MD according to the age of onset of the condition.

METHODS

A cross-sectional study including 83 MD patients: 44 with early-onset MD (EOMD, <35 years old), and 39 with late-onset MD (LOMD, >50 years old), 64 patients with migraine and 55 controls was carried out. Clinical variables and cytokines levels of CCL3, CCL4, CCL18, CCL22, CXCL,1 and IL-1β were compared among the different groups.

RESULTS

CCL18 levels were higher in patients with migraine or MD than in controls. Elevated levels of IL-1β were observed in 11.4% EOMD and in 10.3% LOMD patients and these levels were not dependent on the age of individuals. EOMD had a longer duration of the disease (p = 0.004) and a higher prevalence of migraine than LOMD (p = 0.045).

CONCLUSIONS

Patients with EOMD have a higher prevalence of migraine than LOMD, but migraine is not associated with any cytokine profile in patients with MD. The levels of CCL18, CCL3, and CXCL4 were different between patients with MD or migraine and controls.

Role of Neuroinflammation and Blood-Brain Barrier Permutability on Migraine

Currently, migraine is treated mainly by targeting calcitonin gene-related peptides, although the efficacy of this method is limited and new treatment strategies are desired. Neuroinflammation has been implicated in the pathogenesis of migraine. In patients with migraine, peripheral levels of pro-inflammatory cytokines, such as interleukin-1β (IL-1β) and tumor necrosis factor-α, are known to be increased. Additionally, animal models of headache have demonstrated that immunological responses associated with cytokines are involved in the pathogenesis of migraine. Furthermore, these inflammatory mediators might alter the function of tight junctions in brain vascular endothelial cells in animal models, but not in human patients. Based on clinical findings showing elevated IL-1β, and experimental findings involving IL-1β and both the peripheral trigeminal ganglion and central trigeminal vascular pathways, regulation of the Il-1β/IL-1 receptor type 1 axis might lead to new treatments for migraine. However, the integrity of the blood-brain barrier is not expected to be affected during attacks in patients with migraine.

Association of Migraine with Its Comorbidities and Food Specific Immunoglobulin G Antibodies and Inflammatory Cytokines: Cross-Sectional Clinical Research

Purpose

The relationship between food allergy caused by food specific IgG antibodies and migraine has received increased attention in recent years. Here, we aimed to evaluate the effects of food specific IgG antibodies on headache, gastrointestinal symptoms, anxiety, depression, sleep disorders, dermatosis, and serum inflammatory cytokines in migraine patients, and to quantitatively assess the effect of IgG levels on the severity of headache and its comorbidities.

Methods

Of 89 migraine patients, those who had one or more food specific IgG antibodies ≥50 U/mL were classified into the IgG positive group, which was then further divided into subgroups based on differing numbers of food allergens. All other subjects were classified into the IgG negative group. We compared the frequency and severity of migraine, anxiety, depression, sleep disorders, dermatosis, and inflammatory cytokines between groups. A regression model was performed to further assess the effect of overall positive IgG concentration and the mediation effect of inflammatory cytokines.

Results

Participants in the positive IgG group (n = 67) were more likely to have longer time elapsed since diagnosis, more frequent and severe migraine, a higher risk of developing anxiety and gastrointestinal symptoms, along with higher IL-6 and TNF-α. Subgroups with more food allergens generally had worse conditions as well. After adjusting for the inflammatory cytokines, the effect of IgG was reduced.

Conclusion

Migraine patients with positive food specific IgG antibodies had worse migraine, anxiety, and gastrointestinal symptoms. Inflammatory cytokines partially mediate the causal pathway between food specific IgG antibodies, migraine, and migraine comorbidities.

Migraine and neuroinflammation: the inflammasome perspective

BACKGROUND

Neuroinflammation has an important role in the pathophysiology of migraine, which is a complex neuro-glio-vascular disorder. The main aim of this review is to highlight findings of cortical spreading depolarization (CSD)-induced neuroinflammatory signaling in brain parenchyma from the inflammasome perspective. In addition, we discuss the limited data of the contribution of inflammasomes to other aspects of migraine pathophysiology, foremost the activation of the trigeminovascular system and thereby the generation of migraine pain.

MAIN BODY

Inflammasomes are signaling multiprotein complexes and key components of the innate immune system. Their activation causes the production of inflammatory cytokines that can stimulate trigeminal neurons and are thus relevant to the generation of migraine pain. The contribution of inflammasome activation to pain signaling has attracted considerable attention in recent years. Nucleotide-binding domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) is the best characterized inflammasome and there is emerging evidence of its role in a variety of inflammatory pain conditions, including migraine. In this review, we discuss, from an inflammasome point of view, cortical spreading depolarization (CSD)-induced neuroinflammatory signaling in brain parenchyma, the connection with genetic factors that make the brain vulnerable to CSD, and the relation of the inflammasome with diseases that are co-morbid with migraine, including stroke, epilepsy, and the possible links with COVID-19 infection.

CONCLUSION

Neuroinflammatory pathways, specifically those involving inflammasome proteins, seem promising candidates as treatment targets, and perhaps even biomarkers, in migraine.

Over-expression of IL-6 coding gene in the peripheral blood of migraine with aura patients

Migraine is a common disorder which is placed among the top ten reasons of years lived with disability. Cytokines are among the molecules that contribute in the pathophysiology of migraine. In the current study, we evaluated expression levels of IL-6 coding gene in the peripheral blood of 120 migraine patients (54 migraine without aura and 66 migraine with aura patients) and 40 healthy subjects. No significant difference was detected in expression of IL-6 between total migraine patients and healthy controls (Posterior beta = 0.253, P value = 0.199). The interaction effect between gender and group was significant (Posterior beta =-1.274, P value = 0.011), therefore, we conducted subgroup analysis within gender group. Such analysis revealed that while expression of this gene is not different between male patients and male controls (Posterior beta =-0.371, P value > 0.999), it was significantly over-expressed in female patients compared with female controls (Posterior beta = 0.86, P= 0.002). Expression of IL-6 was significantly higher in patients with aura compared with controls (Posterior beta = 0.63, adjusted P value = 0.019). However, expression of this cytokine coding gene was not different between patients without aura and healthy subjects (Posterior beta = 0.193, adjusted P value = 0.281). Therefore, IL-6 might be involved in the pathophysiology of migraine among females and migraine with aura among both sexes.

Network Pharmacology and Metabolomics Studies on Antimigraine Mechanisms of Da Chuan Xiong Fang (DCXF)

Background

Da Chuan Xiong Fang (DCXF) is a traditional Chinese medicine (TCM) formula used to treat migraines. Previously, we uncovered partial mechanisms involved in the therapeutic actions of DCXF on migraines.

Methods

In this study, we further elucidated its antimigraine mechanisms in vivo by using an integrated strategy coupling with network pharmacology and metabolomics techniques.

Results

Network pharmacology identified 33 genes linked with both migraine and DCXF, most of which were 5-hydroxytryptamine receptors, dopamine, and peptide receptors. The results of GO and KEGG enrichment analysis showed that DCXF significantly regulated tyrosine metabolism, tryptophan metabolism, dopamine metabolic process, glucose transmembrane transport, lipid metabolism, and fatty acid transport. The results of metabolomics analysis found that the metabolism of tryptophan and tyrosine in the brain tissue and energy and lipid metabolism of rats tended towards normal and reached normal levels after administering DCXF. The metabolomics and network pharmacology approaches demonstrated similar antimigraine effects of DCXF on endogenous neurotransmitters and overall trends in serum and brain tissue. Using both approaches, 62 hub genes were identified from the protein-protein interaction (PPI) network of DCXF and gene-metabolite interaction network, with hub genes and different metabolites in serum and brain tissue. The hub genes of DCXF, which were mostly linked with inflammation, might affect mainly neurotransmitters in serum and brain tissue metabolisms.

Conclusion

Network pharmacology and metabolomics study may help identify hub genes, metabolites, and possible pathways of disease and treatment. Additionally, two parts of the results were integrated to confirm each other. Their combination may help elucidate the relationship between hub genes and metabolites and provide the further understanding of TCM mechanisms.

A systematic review and meta-analysis of recent studies reporting hormone levels related to thyroid gland function in migraineurs, until April 2020

PURPOSE

The purpose of the current study was to evaluate thyroid function in terms of serum thyroid-stimulating hormone (TSH, also known as thyrotropin), 3,5,3'-triiodo-L-thyronine (T3), and 3,5,3',5'-tetraiodo-L-thyronine (T4, also known as thyroxine) levels in migraineurs in comparison with non-migraineurs using a systematic review of literature and a meta-analysis.

METHODS

This is a systematic review of case-control studies on serum TSH, T3, and T4 concentrations of migraineurs in comparison with non-migraineurs. After extracting the data from the finally included studies, the weighted overall standardized mean difference (SMD) was calculated.

RESULTS

The weighted overall SMD for the impact of TSH, T3, and T4 blood levels for migraineurs in comparison with non-migraineurs was as follows: 0.804 (95% CI, 0.045-1.564), - 0.267 (95% CI, - 0.660-0.125), 0.093 (95% CI, - 0.077-0.263), respectively. It is noteworthy that only the p value for the significance of the overall SMD for serum TSH level was statistically significant (p = 0.038), as examined by the z-test.

CONCLUSIONS

The results of the current study point to an association between migraine pathogenesis and changing TSH levels in comparison with those of controls.

The Efficacy of Vitamin D Supplementation for Migraine: A Meta-Analysis of Randomized Controlled Studies

INTRODUCTION

The efficacy of vitamin D for migraine remains controversial. We conduct a systematic review and meta-analysis to explore the influence of vitamin D versus placebo on treatment in migraine patients.

METHODS

We search PubMed, EMbase, Web of Science, EBSCO, and Cochrane library databases through April 2020 for randomized controlled trials assessing the effect of vitamin D versus placebo on treatment efficacy in migraine patients. This meta-analysis is performed using the random-effect model.

RESULTS

Five randomized controlled trials are included in the meta-analysis. Overall, compared with control group in migraine patients, vitamin D treatment is associated with substantially reduced number of headache days (standard mean difference [SMD], -0.53; 95% confidence interval [CI], -0.83 to -0.23; P = 0.0006), frequency of headache attacks (SMD, -1.09; 95% CI, -1.86 to -0.32; P = 0.006), headache severity (SMD, -0.55; 95% CI, -0.91 to -0.19; P = 0.0003), and Migraine Disability Assessment score (SMD, -0.76; 95% CI, -1.11 to -0.40; P < 0.0001).

CONCLUSIONS

Vitamin D treatment is effective to alleviate migraine.

Differential Expression of Cytokine-Coding Genes among Migraine Patients with and without Aura and Normal Subjects

Migraine is a prevalent disorder in humans and represents one of the top 10 causes of years lived with disability. Several genetic and environmental factors are involved in the pathobiology of migraine. A number of studies have underscored the role of dysregulated immune reactions. We compared the expression levels IL-2, IL-4, CXCL8, IL-17, IFN-γ, TGF-β and TNF-α cytokines in blood specimens of patients with migraine and those of healthy persons to identify any possible dysregulation in their expression and to propose mechanisms for this disorder. Expression of INF-γ was suggestively higher in migraine cases than in healthy individuals (posterior beta = 0.35, adjusted P value = 0.017). In addition, expression of this cytokine was lower in female subjects than in male subjects (posterior beta = -0.712, adjusted P value = 0.012). Expression of IL-4, TGF-β and TNF-α was also higher in cases compared with controls (posterior beta = 1.34, adjusted P value = 0.04; posterior beta = 0.849, adjusted P value = 0.036; posterior beta = 0.451, adjusted P value = 0.042, respectively). On the other hand, CXCL8 expression was lower in migraine cases than in controls (posterior beta = -0.78, adjusted P value = 0.039). Expression levels of IL-1B, IL-17 and IL-2 were not meaningfully different between cases and controls. The current study highlights the dysregulation of cytokine-coding genes in the blood of patients with migraine.

RAR-related orphan receptor A: One gene with multiple functions related to migraine

Aims

RAR‐related orphan receptor (RORA) involves in regulation of several biological processes including inflammation and circadian rhythm that probably are involved in migraine pathophysiology. In the current study, the association between RORA rs11639084 and rs4774388 variants and susceptibility to migraine were investigated in a sample of Iranian migraine patients for the first time.

Methods

In a case‐control study including 400 participants, 200 migraineurs and 200 healthy controls, genotyping of RORA rs4774388 and rs11639084 polymorphisms was performed using tetra‐primer amplification refractory mutation system–polymerase chain reaction (TP‐ARMS‐PCR).

Results

The distribution of rs4774388 C/T and T/T genotypes differed significantly between the studied groups. Moreover, an association was observed between rs4774388 and migraine under the recessive mode of inheritance (P = 0.002; OR = 1.89.; CI = 1.25‐2.87). The distribution of rs11639084 alleles and genotypes was not significantly different between migraineurs and healthy controls.

Conclusion

Current results suggest RORA, as a molecular link, may explain inflammation and circadian rhythm dysfunction in migraine. Further studies in different ethnicities are required to confirm the function of RORA in migraine development.

Therapeutic implications of cortical spreading depression models in migraine

Migraine is among the most common and disabling neurological diseases in the world. Cortical spreading depression (CSD) is a wave of near-complete depolarization of neurons and glial cells that slowly propagates along the cortex creating the perception of aura. Evidence suggests that CSD can trigger migraine headache. Experimental models of CSD have been considered highly translational as they recapitulate migraine-related phenomena and have been validated for screening migraine therapeutics. Here we outline the essential components of validated experimental models of CSD and provide a comprehensive review of potential modulators and targets against CSD. We further focus on novel interventions that have been recently shown to suppress CSD susceptibility that may lead to therapeutic targets in migraine.

Anandamide Is Related to Clinical and Cardiorespiratory Benefits of Aerobic Exercise Training in Migraine Patients: A Randomized Controlled Clinical Trial

Introduction: Since endocannabinoids have been implicated in migraine pathophysiology, we conducted a randomized, controlled clinical trial to test the effects of a 12-week aerobic exercise intervention on plasma anandamide (AEA) and its relation with clinical, psychological, and cardiorespiratory outcomes. Materials and Methods: Episodic migraine patients taking no preventive drugs and nonheadache individuals were recruited from Hospital São Paulo and a tertiary headache clinic between March 2012 and March 2015. Participants were randomly assigned to receive aerobic exercise or enter the waitlist. Primary outcome was changes in plasma AEA; secondary outcome was number of days with migraine/month; and other clinical variables, mood scores, and cardiorespiratory fitness were chosen as tertiary outcomes. Measurements were taken on headache-free days. Data were analyzed by generalized linear models. Discussion: Fifty participants concluded the study (mean±SD age=36.2±10.9, and BMI=26.5±4.5). The plasma AEA reduced in migraine exercise (p<0.05) and control exercise groups (p<0.01). The number of days with migraine (p<0.01), migraine attacks (p<0.05), and abortive medication used (p<0.05) reduced in the migraine exercise group, whereas cardiorespiratory fitness increased in migraine exercise and control exercise groups (both p<0.05). Anxiety, depression, anger, and fatigue scores improved in the migraine exercise group (p<0.05 for all). Significant correlations between reduction in abortive medication used and cardiorespiratory fitness (r=-0.81 p<0.001), and reduced AEA (r=0.68 p<0.05) were found. Conclusions: This study suggests that peripheral AEA metabolism may be partly linked to the clinical and cardiorespiratory benefits of regular aerobic exercise in migraine patients. Trials registration: #NCT01972607.

Upregulation of IL-1 Receptor Antagonist in a Mouse Model of Migraine

Migraine is a disorder characterized by attacks of monolateral headaches, often accompanied by nausea, vomiting, and photophobia. Around 30% of patients also report aura symptoms. The cause of the aura is believed to be related to the cortical spreading depression (CSD), a wave of neuronal and glial depolarization originating in the occipital cortex, followed by temporary neuronal silencing. During a migraine attack, increased expression of inflammatory mediators, along with a decrease in the expression of anti-inflammatory genes, have been observed. The aim of this study was to evaluate the expression of inflammatory genes, in particular that of IL-1 receptor antagonist (IL-1RN), following CSD in a mouse model of familial hemiplegic migraine type 1 (FHM-1). We show here that the expression of IL-1RN was upregulated after the CSD, suggesting a possible attempt to modulate the inflammatory response. This study allows researchers to better understand the development of the disease and aids in the search for new therapeutic strategies in migraine.

Latent toxoplasmosis aggravates anxiety- and depressive-like behaviour and suggest a role of gene-environment interactions in the behavioural response to the parasite

Toxoplasma gondii (TOX) is an intracellular parasite which infects warm-blooded animals including humans. An increasing number of clinical studies now hypothesize that latent toxoplasmosis may be a risk factor for the development of psychiatric disease. For depression, the results have been varied and we speculate that genetic background is important for the response to latent toxoplasmosis. The main objective of this study was to elucidate gene - environment interactions in the behavioural response to TOX infection by use of genetically vulnerable animals (Flinders sensitive line, FSL) compared to control animals (Flinders resistant line, FRL). Our results show that all infected animals displayed increased anxiety-like behaviour whereas only genetically vulnerable animals (FSL rats) showed depressive-like behaviour as a consequence of the TOX infection. Furthermore, peripheral cytokine expression was increased following the infection, primarily independent of strain. In the given study 14 cytokines, chemokines, metabolic hormones, and growth factors were quantified with the bead-based Luminex200 system, however, only IL-1α expression was affected differently in FSL animals compared to FRL rats. These results suggest that latent TOX infection can induce anxiety-like behaviour independent of genetic background. Intriguingly, we also report that for depressive-like behaviour only the vulnerable rat strain is affected. This could explain the discrepancy in the literature as to whether TOX infection is a risk factor for depressive symptomatology. We propose that the low grade inflammation caused by the chronic infection is related to the development of behavioural symptoms.

Weight loss and improved mood after aerobic exercise training are linked to lower plasma anandamide in healthy people

Anandamide, a major endocannabinoid, participates in energy metabolism homeostasis and neurobehavioral processes. In a secondary analysis of an open-label, randomized controlled trial, we investigated the long-term effect of aerobic exercise on resting plasma anandamide, and explored its relationship with changes in body weight, cardiorespiratory fitness, and mood status in healthy, physically inactive individuals. Participants recruited between March 2013 to August 2015 at the UNIFESP's Neurology/Psychobiology Department were randomly allocated into a 12-weeks supervised moderate exercise program, or into waitlist, control condition. Thirty-four participants (age = 38 ± 11.5, BMI = 26.6 ± 3.6) were intention to treat-analysed (Exercise: n = 17; Control: n = 17). After intervention, there were significant decreases in plasma anandamide (p < .01), anger, anxiety, and body weight (all p < .05), whereas cardiorespiratory fitness increased (p < .05) in the exercise group. There were no significant changes in any variable for the control group. In the whole cohort, adjusted R² of multiple linear regressions showed that 12.2% of change body weight was explained by changes in anandamide (β = 0.391, p = .033), while 27% of change in mood disturbance (β = 0.546, p = .003), and 13.1% of change in anger (β = 0.404, p = .03) was explained by changes in anandamide. Our data suggest that the weight loss and mood improvement through regular moderate exercise may involve changes in anandamide metabolism/signaling. Trials registration: #NCT01972607.

The serum level of inflammatory markers in chronic and episodic migraine: a case-control study

The exact mechanism of the migraine pathophysiology remained unclear. Although there are some reports showing low-grade inflammation in migraineurs, further studies are needed in this field. Thus, we designed a study to evaluate the serum levels of two main proinflammatory markers in migraine patients. In this case-control research, 43 migraine patients (23 chronic and 20 episodic migraineurs) and 40 age-sex-matched headache-free controls were studied. Demographic, dietary, and anthropometric data, headache characteristics, and serum C-reactive proteins (CRP) and tumor necrosis factor-alpha (TNF-α) assessments were collected. The mean ± SD age of the case and control groups were 36.98 ± 9.91 and 34.84 ± 9.75 years respectively. Compared to control subjects, both episodic and chronic migraineurs had significantly higher median levels of TNF-α (0.24, 0.95, and 1.90 pg/ml, respectively; P value < 0.001). Also, we observed a positive association between the TNF-α levels and the odds of having migraine after considering gender, age, body mass index, and dietary intakes of energy, carbohydrate, protein, fat, and mono and poly unsaturated fatty acids in the multivariable regression models (OR = 2.15; 95% CI 1.31-3.52; P value < 0.001). However, no significant association was demonstrated between migraine and serum CRP (OR = 2.91; 95% CI 0.87-9.78; P value = 0.08). These findings supported that inflammatory state could be related to the pathogenesis of migraine and it can thus be suggested that this effect might be beyond migraine progression. Further detailed studies are needed to investigate the importance of these findings in the pathogenesis of migraine headache.