Increased serum levels of brain-derived neurotropic factor during migraine attacks: a pilot study

Relationship between plasma brain-derived neurotrophic factor levels and neurological disorders: An investigation using Mendelian randomisation

Background

Altered brain-derived neurotrophic factor (BDNF) concentrations have been detected in the central nervous system tissues and peripheral blood. These alterations are associated with a series of neurological disorders.

Objective

To investigate the potential causal relationships between genetically determined plasma BDNF levels and various neurological diseases using a two-sample Mendelian randomisation study.

Methods

We selected single nucleotide polymorphisms strongly related to plasma BDNF levels as instrumental variables. Within the Mendelian randomisation framework, we used summary-level statistics for exposure (plasma BDNF levels) and outcomes (neurological disorders).

Results

We observed suggestive evidence of a relation between higher plasma BDNF levels and less risk of nontraumatic intracranial haemorrhage (nITH) (odds ratio [OR] = 0.861, 95 % confidence interval [CI]: 0.774-0.958, P = 0.006, PFDR = 0.078), epilepsy (OR = 0.927, 95 % CI: 0.880-0.976, P = 0.004, PFDR = 0.078), focal epilepsy (OR = 0.928, 95 % CI: 0.874-0.986, P = 0.016, PFDR = 0.139), and non-lesional focal epilepsy (OR = 0.981, 95 % CI: 0.964-0.999, P = 0.041, PFDR = 0.267). Combined with the UK Biobank dataset, the association of plasma BDNF levels with nITH remained significant (OR = 0.88, 95 % CI: 0.81-0.96, P < 0.01). The combined analysis of three consortium datasets demonstrated a considerable impact of plasma BDNF on epilepsy (OR = 0.94, 95 % CI: 0.90-0.98, P < 0.01) and a suggestive impact on focal epilepsy (OR = 0.94, 95 % CI: 0.89-0.99, P = 0.02). However, there was no apparent correlation between plasma BDNF levels and other neurological disorders or related subtypes.

Conclusions

Our study supports a possible causal relationship between elevated plasma BDNF levels and a reduced risk of nITH, epilepsy, and focal epilepsy.

Vagus nerve stimulation inhibits cortical spreading depression via glutamate-dependent TrkB activation mechanism in the nucleus tractus solitarius

BACKGROUND

Vagus nerve stimulation (VNS) was recently found to inhibit cortical spreading depression (CSD), the underlying mechanism of migraine aura, through activation of the nucleus tractus solitarius (NTS), locus coeruleus (LC) and dorsal raphe nucleus (DRN). The molecular mechanisms underlying the effect of VNS on CSD in these nuclei remain to be explored. We hypothesized that VNS may activate glutamate receptor-mediated tropomyosin kinase B (TrkB) signaling in the NTS, thereby facilitating the noradrenergic and serotonergic neurotransmission to inhibit CSD.

METHODS

To investigate the role of TrkB and glutamate receptors in non-invasive VNS efficacy on CSD, a validated KCl-evoked CSD rat model coupled with intra-NTS microinjection of selective antagonists, immunoblot and immunohistochemistry was employed.

RESULTS

VNS increased TrkB phosphorylation in the NTS. Inhibition of intra-NTS TrkB abrogated the suppressive effect of VNS on CSD and CSD-induced cortical neuroinflammation. TrkB was found colocalized with glutamate receptors in NTS neurons. Inhibition of glutamate receptors in the NTS abrogated VNS-induced TrkB activation. Moreover, the blockade of TrkB in the NTS attenuated VNS-induced activation of the LC and DRN.

CONCLUSIONS

VNS induces the activation of glutamate receptor-mediated TrkB signaling in the NTS, which might modulate serotonergic and norepinephrinergic innervation to the cerebral cortex to inhibit CSD and cortical inflammation.

Understanding the Biological Relationship between Migraine and Depression

Migraine is a highly prevalent neurological disorder. Among the risk factors identified, psychiatric comorbidities, such as depression, seem to play an important role in its onset and clinical course. Patients with migraine are 2.5 times more likely to develop a depressive disorder; this risk becomes even higher in patients suffering from chronic migraine or migraine with aura. This relationship is bidirectional, since depression also predicts an earlier/worse onset of migraine, increasing the risk of migraine chronicity and, consequently, requiring a higher healthcare expenditure compared to migraine alone. All these data suggest that migraine and depression may share overlapping biological mechanisms. Herein, this review explores this topic in further detail: firstly, by introducing the common epidemiological and risk factors for this comorbidity; secondly, by focusing on providing the cumulative evidence of common biological aspects, with a particular emphasis on the serotoninergic system, neuropeptides such as calcitonin-gene-related peptide (CGRP), pituitary adenylate cyclase-activating polypeptide (PACAP), substance P, neuropeptide Y and orexins, sexual hormones, and the immune system; lastly, by remarking on the future challenges required to elucidate the etiopathological mechanisms of migraine and depression and providing updated information regarding new key targets for the pharmacological treatment of these clinical entities.

Current Update on Categorization of Migraine Subtypes on the Basis of Genetic Variation: a Systematic Review

Migraine is a complex neurovascular disorder that is characterized by severe behavioral, sensory, visual, and/or auditory symptoms. It has been labeled as one of the ten most disabling medical illnesses in the world by the World Health Organization (Aagaard et al Sci Transl Med 6(237):237ra65, 2014). According to a recent report by the American Migraine Foundation (Shoulson et al Ann Neurol 25(3):252-9, 1989), around 148 million people in the world currently suffer from migraine. On the basis of presence of aura, migraine is classified into two major subtypes: migraine with aura (Aagaard et al Sci Transl Med 6(237):237ra65, 2014) and migraine without aura. (Aagaard K et al Sci Transl Med 6(237):237ra65, 2014) Many complex genetic mechanisms have been proposed in the pathophysiology of migraine but specific pathways associated with the different subtypes of migraine have not yet been explored. Various approaches including candidate gene association studies (CGAS) and genome-wide association studies (Fan et al Headache: J Head Face Pain 54(4):709-715, 2014). have identified the genetic markers associated with migraine and its subtypes. Several single nucleotide polymorphisms (Kaur et al Egyp J Neurol, Psychiatry Neurosurg 55(1):1-7, 2019) within genes involved in ion homeostasis, solute transport, synaptic transmission, cortical excitability, and vascular function have been associated with the disorder. Currently, the diagnosis of migraine is majorly behavioral with no focus on the genetic markers and thereby the therapeutic intervention specific to subtypes. Therefore, there is a need to explore genetic variants significantly associated with MA and MO as susceptibility markers in the diagnosis and targets for therapeutic interventions in the specific subtypes of migraine. Although the proper characterization of pathways based on different subtypes is yet to be studied, this review aims to make a first attempt to compile the information available on various genetic variants and the molecular mechanisms involved with the development of MA and MO. An attempt has also been made to suggest novel candidate genes based on their function to be explored by future research.

Autophagy may protect the brain against prolonged consequences of headache attacks: A narrative/hypothesis review

OBJECTIVE

To assess the potential of autophagy in migraine pathogenesis.

BACKGROUND

The interplay between neurons and microglial cells is important in migraine pathogenesis. Migraine-related effects, such as cortical spreading depolarization and release of calcitonin gene-related peptide, may initiate adenosine triphosphate (ATP)-mediating pro-nociceptive signaling in the meninges causing headaches. Such signaling may be induced by the interaction of ATP with purinergic receptor P2X 7 (P2X7R) on microglial cells leading to a Ca2+ -mediated pH increase in lysosomes and release of autolysosome-like vehicles from microglial cells indicating autophagy impairment.

METHODS

A search in PubMed was conducted with the use of the terms "migraine," "autophagy," "microglia," and "degradation" in different combinations.

RESULTS

Impaired autophagy in microglia may activate secretory autophagy and release of specific proteins, including brain-derived neurotrophic factor (BDNF), which can be also released through the pores induced by P2X7R activation in microglial cells. BDNF may be likewise released from microglial cells upon ATP- and Ca2+ -mediated activation of another purinergic receptor, P2X4R. BDNF released from microglia might induce autophagy in neurons to clear cellular debris produced by oxidative stress, which is induced in the brain as the response to migraine-related energy deficit. Therefore, migraine-related signaling may impair degradative autophagy, stimulate secretory autophagy in microglia, and degradative autophagy in neurons. These effects are mediated by purinergic receptors P2X4R and P2X7R, BDNF, ATP, and Ca2+ .

CONCLUSION

Different effects of migraine-related events on degradative autophagy in microglia and neurons may prevent prolonged changes in the brain related to headache attacks.

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.

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.

Exploring Novel Therapeutic Targets in the Common Pathogenic Factors in Migraine and Neuropathic Pain

Migraine and neuropathic pain (NP) are both painful, disabling, chronic conditions which exhibit some symptom similarities and are thus considered to share a common etiology. The calcitonin gene-related peptide (CGRP) has gained credit as a target for migraine management; nevertheless, the efficacy and the applicability of CGRP modifiers warrant the search for more effective therapeutic targets for pain management. This scoping review focuses on human studies of common pathogenic factors in migraine and NP, with reference to available preclinical evidence to explore potential novel therapeutic targets. CGRP inhibitors and monoclonal antibodies alleviate inflammation in the meninges; targeting transient receptor potential (TRP) ion channels may help prevent the release of nociceptive substances, and modifying the endocannabinoid system may open a path toward discovery of novel analgesics. There may exist a potential target in the tryptophan-kynurenine (KYN) metabolic system, which is closely linked to glutamate-induced hyperexcitability; alleviating neuroinflammation may complement a pain-relieving armamentarium, and modifying microglial excitation, which is observed in both conditions, may be a possible approach. Those are several potential analgesic targets which deserve to be explored in search of novel analgesics; however, much evidence remains missing. This review highlights the need for more studies on CGRP modifiers for subtypes, the discovery of TRP and endocannabinoid modulators, knowledge of the status of KYN metabolites, the consensus on cytokines and sampling, and biomarkers for microglial function, in search of innovative pain management methods for migraine and NP.

Plasma Brain-Derived Neurotrophic Factor and Opioid Therapy: Results of Pilot Cross-Sectional Study

Objective: The neurotoxic effect of opioid has not been thoroughly described. No studies have been conducted to explain the effect of opioids in chronic non-cancer pain therapy on the neurotrophic factors level. Due to the ability to cross the blood-brain barrier, it seems the determination of serum Brain-derived neurotrophic factor (BDNF) concentration is a reliable presentation of the concentration in the central nervous system. The aim of the study was to explore the changes of plasma BDNF concentration during long-term opioid therapy.Methods: The study group included 28 patients with chronic low back pain treated with opioid therapy buprenorphine (n=10), tramadol (n=8), oxycodone (n=6), morphine (n=3), fentanyl (n=1). The control group included 11 patients. Measurements of plasma BDNF concentrations were performed, and information about opioid therapy were recorded (age, sex, opioid substance type, daily dose and the duration of opioid therapy). Data were analyzed using nonparametric tests.Results: The median BDNF level in the study group was significantly lower (2.73 ng/mL) than that in the control group (5.04 ng/mL, P<0.05). BDNF levels did not differ among groups based on the type of opioid substance used, but the lowest median value was observed for tramadol (2.62 ng/mL), and the highest median value was observed for buprenorphine (2.73 ng/mL). The widest minimum-maximum ranges of BDNF for oxycodone were noted, minimum 1.23 ng/mL and maximum 4.57 ng/mL, respectively. BDNF concentrations were correlated with age in the tramadol group and with the duration of opioid therapy in the buprenorphine group.Conclusion: Chronic opioid therapy for noncancer pain induces specific changes in the BDNF concentration. Tramadol and buprenorphine exerted an important effect on BDNF levels in the examined patients. The BDNF level depends on duration of opioid therapy with buprenorphine, and age in tramadol therapy.

Selected Factors of Vascular Changes: The Potential Pathological Processes Underlying Primary Headaches in Children

Background: The prevalence, social consequences and complicated pathogenesis make headaches in children a significant clinical issue. Studies in adults suggest that primary headaches could be the first sign of atherosclerosis and platelet aggregation. Aim: To analyze the blood levels of selected biomarkers of vascular changes potentially associated with a higher risk of atherosclerosis in children with primary headaches. Methods: The medical family history, brain-derived neurotrophic factor (BDNF), soluble CD40 ligands (sCD40L), endothelial plasminogen activator inhibitor (PAI I), vascular endothelial growth factor (VEGF) and intima-media thickness (IMT) measurements were performed in the 83 children (52 with primary headaches, 31 controls). Selected factors were compared with basic laboratory parameters that are potentially related to atherosclerosis: C-reactive protein (CRP) and lipid concentration. Results: There were no significant differences in biomarkers of vascular changes in the study group and controls in general. In the study group, boys had a higher BDNF level than girls (p = 0.046). Normal-weight migraine patients had significantly higher PAI-I levels than controls (p = 0.034). A positive correlation between PAI-1 and triglycerides (TG) was observed. IMT did not differ between children with primary headaches and controls; however, IMT showed a positive correlation with BMI z-score and TG. Children with headaches had, more often, a positive family history of cardiovascular disease (p = 0.049). Conclusions: There were no clear clinical changes indicative of atherosclerosis in the study population. However, some trends are visible. Primary headaches are more often related to a family history of cardiovascular diseases. IMT is associated with TG levels and BMI z-score. The measured biomarkers of vascular changes show mutual relations.

Immunologic aspects of migraine: A review of literature

Migraine headaches are highly prevalent, affecting 15% of the population. However, despite many studies to determine this disease's mechanism and efficient management, its pathophysiology has not been fully elucidated. There are suggested hypotheses about the possible mediating role of mast cells, immunoglobulin E, histamine, and cytokines in this disease. A higher incidence of this disease in allergic and asthma patients, reported by several studies, indicates the possible role of brain mast cells located around the brain vessels in this disease. The mast cells are more specifically within the dura and can affect the trigeminal nerve and cervical or sphenopalatine ganglion, triggering the secretion of substances that cause migraine. Neuropeptides such as calcitonin gene-related peptide (CGRP), neurokinin-A, neurotensin (NT), pituitary adenylate-cyclase-activating peptide (PACAP), and substance P (SP) trigger mast cells, and in response, they secrete pro-inflammatory and vasodilatory molecules such as interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) as a selective result of corticotropin-releasing hormone (CRH) secretion. This stress hormone contributes to migraine or intensifies it. Blocking these pathways using immunologic agents such as CGRP antibody, anti-CGRP receptor antibody, and interleukin-1 beta (IL-1β)/interleukin 1 receptor type 1 (IL-1R1) axis-related agents may be promising as potential prophylactic migraine treatments. This review is going to summarize the immunological aspects of migraine.

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.

Could Experimental Inflammation Provide Better Understanding of Migraines?

Migraines constitute a common neurological and headache disorder affecting around 15% of the world’s population. In addition to other mechanisms, neurogenic neuroinflammation has been proposed to play a part in migraine chronification, which includes peripheral and central sensitization. There is therefore considerable evidence suggesting that inflammation in the intracranial meninges could be a key element in addition to calcitonin gene-related peptide (CGRP), leading to sensitization of trigeminal meningeal nociceptors in migraines. There are several studies that have utilized this approach, with a strong focus on using inflammatory animal models. Data from these studies show that the inflammatory process involves sensitization of trigeminovascular afferent nerve terminals. Further, by applying a wide range of different pharmacological interventions, insight has been gained on the pathways involved. Importantly, we discuss how animal models should be used with care and that it is important to evaluate outcomes in the light of migraine pathology.

DNA Damage and Repair in Migraine: Oxidative Stress and Beyond

Energy generation in the brain to ameliorate energy deficit in migraine leads to oxidative stress as it is associated with reactive oxygen species (ROS) that may damage DNA and show a pronociceptive action in meninges mediated by transient receptor potential cation channel subfamily A member 1 (TRPA1). Recent studies show high levels of single-strand breaks (SSBs) at specific sites in the genome of postmitotic neurons and point at SSB repair (SSBR) as an important element of homeostasis of the central nervous system. DNA topoisomerase 1 (TOP1) is stabilized in the DNA damage-inducing state by neuronal stimulation, including cortical spreading depression. Impairment in poly (ADP-ribose) polymerase 1 (PARP-1) and X-ray repair cross complementing 1 (XRCC1), key SSBR proteins, may be linked with migraine by transient receptor potential melastatin 2 (TRPM2). TRPM2 may also mediate the involvement of migraine-related neuroinflammation with PARP-1 activated by oxidative stress-related SSBs. In conclusion, aberrant activity of SSBR evoked by compromised PARP-1 and XRCC1 may contribute to pathological phenomena in the migraine brain. Such aberrant SSBR results in the lack of repair or misrepair of SSBs induced by ROS or resulting from impaired TOP1. Therefore, components of SSBR may be considered a prospective druggable target in migraine.

Assessment of peripheral biomarkers potentially involved in episodic and chronic migraine: a case-control study with a focus on NGF, BDNF, VEGF, and PGE2

Background

Several inflammatory and vascular molecules, and neurotrophins have been suggested to have a possible role in the development of migraine. However, pathophysiological events leading to migraine onset and transformation of episodic migraine (EM) to chronic migraine (CM) are not fully understood. Thus, we aimed to assess peripheral levels of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), and prostaglandin E2 (PGE2) in EM and CM patients, and controls.

Methods

From September 2017 to June 2020, 89 subjects were enrolled in a case-control study; 23 and 36 EM and CM patients, respectively, and 30 age and sex-matched controls. Demographic data and medical history were obtained from all patients. Headache characteristics were recorded at baseline visit and ensuing 30 days for persons with migraine disease. Serum levels of NGF, BDNF, VEGF, and PGE2 were measured once for controls and EM and CM patients, and adjusted for age, sex, and body mass index.

Results

Serum levels of NGF were significantly lower in EM patients compared to controls and CM patients (P-value=0.003 and 0.042, respectively). Serum levels of BDNF were significantly lower in EM and CM patients as opposed to controls (P-value<0.001), but comparable between EM and CM patients (P-value=0.715). Peripheral blood levels of VEGF were significantly higher in EM and CM patients as opposed to controls (P-value<0.001), but not different between EM and CM patients (P-value=0.859). Serum levels of PGE2 were significantly lower in EM patients compared to controls (P-value=0.011), however similar between EM and CM patients (P-value=0.086). In migraine patients, serum levels of NGF and PGE2 positively correlated with headache frequency (NGF: ρ = 0.476 and P-value<0.001; PGE2: ρ = 0.286 and P-value=0.028), while corresponding levels of BDNF and VEGF did not correlate with headache frequency (BDNF: ρ = 0.037 and P-value=0.778; VEGF: ρ= -0.025 and P-value=0.850).

Conclusions

Our findings suggest that NGF, BDNF, PGE2, and VEGF may play a significant role in migraine pathogenesis and/or chronification, and therefore might bear potential value for novel targeted abortive and prophylactic migraine therapy. Further prospective cohort studies with larger sample sizes can more robustly evaluate the implications of these findings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-021-01377-6.

Polymorphisms of Nav1.6 sodium channel, Brain-derived Neurotrophic Factor, Catechol-O-methyltransferase and Guanosine Triphosphate Cyclohydrolase 1 genes in trigeminal neuralgia

SUBJECTS

Trigeminal neuralgia is a neuropathic pain characterized by episodes of severe shock-like pain within the distribution of one or more divisions of the trigeminal nerve. Pain can be influenced by ethnicity, environment, gender, psychological traits, and genetics. Molecules Nav1.6 sodium channel, Brain-derived Neurotrophic Factor, Catechol-O-methyltransferase and Guanosine Triphosphate Cyclohydrolase 1 have been involved in mechanisms that underlie pain and neurological conditions.

OBJECTIVE

The aim of this case-control study was to investigate the occurrence of genetic polymorphisms in Nav1.6 sodium channel (SCN8A/rs303810), Brain-derived Neurotrophic Factor (BDNF/rs6265/Val66Met), Catechol-O-methyltransferase (COMT/rs4680/Val158Met), and Guanosine Triphosphate Cyclohydrolase 1 (GCH1/rs8007267) genes in trigeminal neuralgia patients.

METHODS

Ninety-six subjects were divided into two groups: 48 with trigeminal neuralgia diagnosis and 48 controls. Pain was evaluated by visual analog scale and genomic DNA was obtained from oral swabs and analyzed by real-time polymerase chain reaction.

RESULTS

No association was observed among SCN8A, BDNF, COMT or GCH1 polymorphisms and the presence of trigeminal neuralgia. Genotype distribution and allele frequencies did not correlate to pain severity.

CONCLUSIONS

Although no association of evaluated polymorphisms and trigeminal neuralgia or pain was observed, our data contributes to the knowledge of genetic susceptibility to trigeminal neuralgia, which is very scarce. Further studies may focus on other polymorphisms and mutations, as well as on epigenetics and transcriptional regulation of these genes, in order to clarify or definitively exclude the role of Nav1.6, BDNF, COMT or GCH1 in trigeminal neuralgia susceptibility and pathophysiology.

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.

Val66Met polymorphism is associated with decreased likelihood for pediatric headache and migraine

Background: Migraine is a complex multifactorial disorder and its pathogenesis still remains unclear. Evidence suggests the involvement of the activated trigeminovascular pathway, in which BDNF seems to play an important role. Therefore, BDNF polymorphisms are promising candidate susceptibility factors.Aim: BDNF rs6265 functional polymorphism was analyzed in order to determine its possible association with pediatric headache and migraine risk.Methods: The research included 120 consecutive pediatric patients who were diagnosed with headache and 120 healthy controls. The diagnosis was in compliance with the International Classification of Headache Disorders. Blood samples were collected from all participants and genotyped for rs6265.Results: BDNF rs6265 was significantly associated with decreased headache risk, particularly in the dominant model [Odds Ratio, OR (95% confidence interval, C.I.): 0.47 (0.26-0.85), p = 0.011] and the log-additive model [OR (95% C.I.): 0.48 (0.28-0.82), p = 0.0053]. During the sensitivity analysis, the associations were also maintained among patients with migraine.Conclusions: This is the first study to reveal a significant association of this BDNF variant with headache risk. Additionally, Val66Met was also for the first time related to decreased childhood migraine risk.

Exercise in Treatment of Migraine Including Chronic Migraine

PURPOSE OF REVIEW

With this review, we aimed to investigate the effect of exercise on migraine and explored the possibility of exercise as a treatment option for migraine.

RECENT FINDINGS

A close association of physical activity and exercise with migraine has been reported in clinical and population-based studies. Recent randomized controlled trials investigating the effect of aerobic exercise as a migraine-preventive treatment have revealed a notable improvement in migraine symptoms. Data on the effect of anaerobic exercise and exercise for flexibility, coordination, and relaxation on migraine are currently insufficient to make any recommendations. Possible pathways for the attenuation of migraine by exercise include the endogenous opioid and cannabinoid systems, brain-derived neurotrophic factor, inflammation, and behavioral/psychological factors. Regarding efficacy, side effects, and health benefits, aerobic exercise is a potentially beneficial strategy in the preventive treatment of migraine. Further studies are needed to delineate an evidence-based exercise program for migraine treatment.

Anti-Neuroinflammatory Properties of n-3 Fatty Acids and Nano- Curcumin on Migraine Patients from Cellular to Clinical Insight: A Randomized, Double-Blind and Placebo-Controlled Trial

BACKGROUND AND OBJECTIVES

Migraine is an exhausting neuro-inflammatory disorder recognized as recurrent headache attacks. Evidence has shown that Interleukin (IL)-1β plays a substantial role in the neuro-immunity pathogenicity of migraine. n-3 fatty acids and curcumin revealed neuromodulatory and anti-inflammatory effects through several pathways, of which the suppression of IL-1β gene expression is an important inflammatory pathway. The aim of this study was the investigation of synergistic relation of n -3 fatty acids and nano-curcumin on IL-1β gene expression and serum levels in migraine patients.

METHODS

This study was performed as a randomized, double-blind, placebo-controlled trial in a period of two months. A total of 80 episodic migraines were assigned into 4 groups of 1) n-3 fatty acids and curcumin combination; 2) n -3 fatty acids; 3) nano-curcumin; and 4) n-3 fatty acids and curcumin placebo. The gene expression and serum level of IL-1β were measured by real-time PCR and ELISA methods respectively, at the beginning and the end of the interventions.

RESULTS

Results showed the n-3 fatty acids and nano-curcumin combination significantly reduced the attack frequency in a synergistic status (P < 0.001). A significantly greater reduction in the serum level of IL-1β was observed in the combination group, and the differences in the other groups were not statistically significant. The IL-1β gene expression in the combination group showed a significant reduction for other treatment groups (P < 0.05), but these significant differences were absent after multiple testing Bonferroni corrections.

CONCLUSION

Present findings revealed that n -3 fatty acids and curcumin co-supplementation can be suggested as a promising new approach in migraine headache management, but further studies are needed to confirm these findings.

De novo protein synthesis is necessary for priming in preclinical models of migraine

BACKGROUND

Migraine attacks are often triggered by normally innocuous stimuli, suggesting that sensitization within the nervous system is present. One mechanism that may contribute to neuronal sensitization in this context is translation regulation of new protein synthesis. The goal of this study was to determine whether protein synthesis contributes to behavioral responses and priming in preclinical models of migraine.

METHODS

Mice received a dural injection of interleukin-6 in the absence or presence of the protein synthesis inhibitor anisomycin or the translation initiation inhibitor 4EGI-1 and were tested for facial hypersensitivity. Upon returning to baseline, mice were given a second, non-noxious dural injection of pH 7.0 to test for priming. Additionally, eIF4E^S209Amice lacking phosphorylation of mRNA cap-binding protein eIF4E received dural interleukin-6 or were subjected to repeated restraint stress and then tested for facial hypersensitivity. After returning to baseline, mice were given either dural pH 7.0 or a systemic sub-threshold dose of the nitric oxide donor sodium nitroprusside and tested for priming.

RESULTS

Dural injection of interleukin-6 in the presence of anisomycin or 4EGI-1 or in eIF4E^S209Amice resulted in the partial attenuation of acute facial hypersensitivity and complete block of hyperalgesic priming. Additionally, hyperalgesic priming following repeated restraint stress was blocked in eIF4E^S209Amice.

CONCLUSIONS

These studies show that de novo protein synthesis regulated by activity-dependent translation is critical to the development of priming in two preclinical models of migraine. This suggests that targeting the regulation of protein synthesis may be a novel approach for new migraine treatment strategies.

Headache in Children: Selected Factors of Vascular Changes Involved in Underlying Processes of Idiopathic Headaches

Headaches are common complaints in children. The International Classification of Headache Disorders, 3^rd edition (beta version), defines more than 280 types of headaches. Primary headaches refer to independent conditions that cause pain and include migraine, tension-type headaches (TTH), and trigeminal autonomic cephalalgias (TACs). Several agents are involved in the pathogenesis of headaches. The factors associated with predisposition to atherosclerosis seem to be particularly important from the clinical point of view. The influence of obesity on the incidence of headaches has been well established. Moreover, idiopathic headaches, especially migraine, are thought to be one of the first signs of disorders in lipid metabolism and atherosclerosis. The risk of migraine increases with increasing obesity in children. Another factor that seems to be involved in both obesity and headaches is the adiponectin level. Recent data also suggest new potential risk factors for atherosclerosis and platelet aggregation such as brain-derived neurotrophic factor (BDNF), sCD40L (soluble CD40 ligand), serpin E1/PAI I (endothelial plasminogen activator inhibitor), and vascular endothelial growth factor (VEGF). However, their role is controversial because the results of clinical studies are often inconsistent. This review presents the current knowledge on the potential markers of atherosclerosis and platelet aggregation, which may be associated with primary headaches.

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.

Assessment of cardiac mechanics and biomarkers during headache attack in migraine patients with aura: a prospective study

Migraine with aura (MA) was found to be associated with increased cardiovascular events (CVE), whereas left ventricular (LV) mechanics were not previously studied in migraineurs. In this study, we aimed to assess LV functions with the utility of two-dimensional speckle tracking echocardiography (2D-STE) and cardiac biomarkers with respect to the headache-free and attack periods and frequency of migraine attacks. Sixty-eight patients with MA were enrolled. During headache-free and attack periods, all patients underwent echocardiographic examination including 2D-STE, and cardiac biomarkers, B-type natriuretic peptide (BNP) and high sensitive cTnT (hs-cTnT) were studied. The impact of headache periods and frequency of attacks on cardiac mechanics and biomarkers were investigated. The mean age of study population was 38.1 ± 7.7 years (56 female) and thirty-one patients (44.6%) had high-frequency migraine attacks. Patients who suffered headache-attack periods had higher frequency of detectable hs-cTnT levels and increased NT-proBNP values which did not differ between low- and high-frequency migraine groups in both periods. Headache attack periods had decreased global longitudinal strain (GLS), increased LV end-systolic volume (LVESV), E/Em ratio and LV torsion (LV-tor) during headache-attack periods. In multivariate analysis; LVESV, LV-tor and high frequency of migraine attacks were associated with decreased GLS (≤ - 20.8), (p 0.038, p 0.026 and p 0.013, respectively). Consequently, 2D-STE findings revealed that migraine attacks, especially with increasing frequencies, could have negative impact on LV mechanics, which adds a new perspective about increased CVE in subjects with MA.

Introducing Genes With Significant Role in Migraine: An Interactomic Approach

Introduction

Migraine is a severe kind of headache with the chance hereditary of 50%. Molecular studies can promote understanding of migraine pathophysiology. One of which is bioinformatics approach that could provide additional information related to the identified biomarkers.

Methods

In this research, migraine genes are studies in terms of interaction pattern to introduce important individuals. Through STRING database Plug-in in Cytoscape, candidate genes for migraine were retrieved and analyzed by related applications. Based on centrality and action types (expression, activation, and inhibition) genes were screened.

Results

Numbers of 33 central genes including seven hub-bottlenecks were identified which 70% of central genes were involved in expression action with each other. Activation was dominate action relative to inhibition between the central genes.

Conclusion

The finding indicates that insulin is the most important gene relative to migraine. It seems regulation of metabolism play critical role in control of migraine.

Electroacupuncture Inhibits Hyperalgesia by Alleviating Inflammatory Factors in a Rat Model of Migraine

Objective

Acupuncture has a therapeutic effect similar to that of prophylactic drugs and can be considered a treatment option for migraineurs. However, the mechanism of acupuncture treatment's effect on migraine is uncertain. An approach based on anti-inflammatory effects is an important treatment strategy for migraine because non-steroidal anti-inflammatory drugs (NSAIDs) are usually used during migraine attacks. Meningeal inflammation is thought to be responsible for the activation of the trigeminovascular system. Our previous study found that electroacupuncture (EA) decreased neurogenic inflammation mediator expression in the trigeminal ganglion (TG) and alleviated hyperalgesia. The present study examined whether EA would inhibit hyperalgesia by alleviating neurogenic inflammatory factors.

Methods

A rat model of migraine was established using dural electrical stimulation (DES). Five groups were analyzed in this study. The Model group received DES three times to mimic migraine attacks, a Control group had sham DES, and three groups received electroacupuncture after DES: a Non-Acu group at a non-acupuncture point, a GB20 group at GB20, and a GB20/34 group at GB20 and GB34 acupuncture points. We evaluated mechanical hyperalgesia using an electronic von Frey esthesiometer in the awake state. After sacrifice, the dura mater was analyzed using immunofluorescence. Serum calcitonin gene-related peptide, cyclooxygenase-2, brain-derived neurotrophic factor, IL-1β, IL-6, and TNF levels were determined using enzyme-linked immunosorbent assays to evaluate the anti-inflammatory effect of acupuncture.

Results

After repeated DES, we observed facial and hind paw mechanical hyperalgesia, which was inhibited by electroacupuncture. Electrical stimulation increased the number of mast cells and macrophages and serum levels of inflammatory factors. GB20 and GB20/34 electroacupuncture significantly decreased the number of mast cells and macrophages and serum levels of inflammatory factors. Moreover, electroacupuncture at GB20/34 was superior to that at GB20 alone in inhibiting hyperalgesia and alleviating inflammatory factors.

Conclusion

Electroacupuncture inhibits DES-induced hyperalgesia by alleviating inflammatory factors. Inhibition of dural mast cells, macrophages, and serum inflammatory factors may be one of the mechanisms involved in acupuncture treatment's effect on migraine.

Effects of Deoxyschisandrin on Visceral Sensitivity of Mice with Inflammatory Bowel Disease

The aims of this study were to build an IBD mouse model and further to observe the effects of deoxyschisandrin on IBD and visceral sensitivity and to evaluate the relevance of brain-derived neurotrophic factor (BDNF) to intestinal hypersensitivity of IBD mice. The results showed that deoxyschisandrin could depress the contraction of isolated smooth muscle, modulate gastrointestinal function, and efficiently decrease the disease activity index (DAI) of IBD mice, which proved that deoxyschisandrin had antidiarrheal effects on the animals. In the colorectal distention (CRD) experiment, visceral sensibility was increased in the model group. However, abdominal withdrawal reflex (AWR) scores were decreased after deoxyschisandrin intervention, indicating that deoxyschisandrin could reduce the visceral hypersensitivity of IBD mice. Both IHC observation and western blotting analysis showed that BDNF protein expression increased evidently in colon of IBD mice. After the intervention of deoxyschisandrin, colon mucosa BDNF protein expression in IBD mice decreased, indicating that deoxyschisandrin could decrease mouse intestinal sensitivity by reducing colon mucosa BDNF expression. In conclusion, deoxyschisandrin possessed antidiarrheal effects and visceral hypersensitivity inhibitory effects in the mice with IBD induced by TNBS, which was related to the reduction in BDNF expression in the colon.

Mechanisms of migraine as a chronic evolutive condition

Understanding the mechanisms of migraine remains challenging as migraine is not a static disorder, and even in its episodic form migraine remains an "evolutive" chronic condition. Considerable progress has been made in elucidating the pathophysiological mechanisms of migraine, associated genetic factors that may influence susceptibility to the disease, and functional and anatomical changes during the progression of a migraine attack or the transformation of episodic to chronic migraine. Migraine is a life span neurological disorder that follows an evolutive age-dependent change in its prevalence and even clinical presentations. As a disorder, migraine involves recurrent intense head pain and associated unpleasant symptoms. Migraine attacks evolve over different phases with specific neural mechanisms and symptoms being involved during each phase. In some patients, migraine can be transformed into a chronic form with daily or almost daily headaches. The mechanisms behind this evolutive process remain unknown, but genetic and epigenetic factors, inflammatory processes and central sensitization may play an important role.

Correlation Between Thalamus-Related Functional Connectivity and Serum BDNF Levels During the Periovulatory Phase of Primary Dysmenorrhea

The thalamus is a key region for the transmission of nociceptive information in the central modulation of pain and has been studied in the setting of numerous chronic pain conditions. Brain-derived neurotrophic factor (BDNF) is considered an important modulator for mediating nociceptive pathways in chronic pain. The present study aimed to investigate whether there was thalamus-related abnormal functional connectivity or relevant serum BDNF level alterations during periovulation in long-term primary dysmenorrhea (PDM). Thalamic subregions were defined according to the Human Brainnetome Atlas. Functional connectivity analyses were performed in 36 patients in the periovulatory phase and 29 age-, education-, and gender-matched healthy controls. Serum BDNF levels were evaluated by enzyme-linked immunosorbent assay and a significantly higher BDNF level was detected in PDM patients. Compared with HCs, PDM patients had abnormal functional connectivity of thalamic-subregions, mainly involving with prefrontal cortex, sensorimotor cortex, and temporal cortex. In addition, the functional connectivity of thalamic-subregions showed significant interactive effect correlated with serum BDNF level between PDM and HCs. It has been suggested that there were maladaptive or adoptive alteration associated with chronic menstrual pain even without the ongoing menstrual pain. BDNF might play a role in the development and chronicity of central nervous system dysfunction. These findings provided more accurate information about the involvement of the thalamus in the pathophysiology of PDM.

P2X4-receptor participates in EAAT3 regulation via BDNF-TrkB signaling in a model of trigeminal allodynia

Objective

Previous studies of neuropathic pain have suggested that the P2X4 purinoceptor (P2X4R) in spinal microglia is essential for maintaining allodynia following nerve injury. However, little is known about its role in inflammatory soup-induced trigeminal allodynia, which closely mimics chronic migraine status. Here, we determined the contributions of P2X4R and related signaling pathways in an inflammatory soup-induced trigeminal allodynia model.

Methods

P2X4R gene and protein levels in the trigeminal nucleus caudalis were analyzed following repeated dural inflammatory soup infusions. p38, brain-derived neurotrophic factor, excitatory amino acid transporter 3, c-Fos, and calcitonin gene-related peptide protein levels in the trigeminal nucleus caudalis, as well as trigeminal sensitivity, were assessed among the different groups. Immunofluorescence staining was used to detect protein localization and expression in the trigeminal nucleus caudalis.

Results

Repeated inflammatory dural stimulation induced trigeminal hyperalgesia and the upregulation of P2X4R. Immunofluorescence revealed that P2X4R was expressed in trigeminal nucleus caudalis microglial cells. Blockage of P2X4R produced an anti-nociceptive effect, which was associated with an inhibition of inflammatory soup-induced increases in p38, brain-derived neurotrophic factor, excitatory amino acid transporter 3, c-Fos, and calcitonin gene-related peptide protein levels. The tyrosine receptor kinase B antagonist ANA-12 reversed trigeminal allodynia and the upregulation of excitatory amino acid transporter 3, c-Fos, and calcitonin gene-related peptide, whereas the agonist 7,8-dihydroxyflavone exacerbated these effects. Double immunostaining indicated that p38 and brain-derived neurotrophic factor were mainly expressed in microglial cells, whereas excitatory amino acid transporter 3 was primarily expressed in trigeminal nucleus caudalis neurons.

Conclusions

These data indicate that microglial P2X4R is involved in the regulation of excitatory amino acid transporter 3 via brain-derived neurotrophic factor-tyrosine receptor kinase B signaling following repeated inflammatory dural stimulation. Microglial P2X4R activation and microglia–neuron interactions in the trigeminal nucleus caudalis may play a role in the pathogenesis of migraine chronicity, and the modulation of P2X4R activation might be a potential therapeutic strategy.

The association between migraine and physical exercise

BACKGROUND

There is an unmet need of pharmacological and non-pharmacological treatment options for migraine patients. Exercise can be used in the treatment of several pain conditions, including. However, what exact role exercise plays in migraine prevention is unclear. Here, we review the associations between physical exercise and migraine from an epidemiological, therapeutical and pathophysiological perspective.

METHODS

The review was based on a primary literature search on the PubMed using the search terms "migraine and exercise".

RESULTS

Low levels of physical exercise and high frequency of migraine has been reported in several large population-based studies. In experimental studies exercise has been reported as a trigger factor for migraine as well as migraine prophylaxis. Possible mechanisms for how exercise may trigger migraine attacks, include acute release of neuropeptides such as calcitonin gene-related peptide or alternation of hypocretin or lactate metabolism. Mechanisms for migraine prevention by exercise may include increased beta-endorphin, endocannabinoid and brain-derived neurotrophic factor levers in plasma after exercise.

CONCLUSION

In conclusion, it seems that although exercise can trigger migraine attacks, regular exercise may have prophylactic effect on migraine frequency. This is most likely due to an altered migraine triggering threshold in persons who exercise regularly. However, the frequency and intensity of exercise that is required is still an open question, which should be addressed in future studies to delineate an evidence-based exercise program to prevent migraine in sufferers.

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.

Dural stimulation in rats causes brain-derived neurotrophic factor-dependent priming to subthreshold stimuli including a migraine trigger

Migraine is one of the most common and most disabling disorders. Between attacks, migraine patients are otherwise normal but are sensitized to nonnoxious events known as triggers. The purpose of these studies was to investigate whether a headache-like event causes sensitization, or priming, to subsequent subthreshold events. Interleukin-6 (IL-6) was applied to the rat cranial dura mater which produced cutaneous facial and hind paw allodynia that lasted 24 hours. At 72 hours, IL-6-treated rats developed allodynia in response to dural stimulation with either a pH 6.8 or pH 7.0 solution and to a systemic nitric oxide (NO) donor, a well-known migraine trigger. Vehicle-treated rats did not respond to either pH stimulus or to the NO donor, demonstrating that IL-6 exposure primes rats to subthreshold stimuli. Inhibitors of brain-derived neurotrophic factor (BDNF) signaling given either systemically or intracisternally 24 hours after IL-6 eliminated responses to dural pH stimulation at 72 hours. Additionally, intracisternal administration of BDNF without previous dural stimulation produced allodynia and once resolved, animals were primed to dural pH 6.8/pH 7.0 and a systemic NO donor. Finally, hind paw IL-6 produced paw allodynia but not priming to paw injection of pH 7.0 at 72 hours demonstrating differences in priming depending on location. These data indicate that afferent input from the meninges produces BDNF-dependent priming of the dural nociceptive system. This primed state mimics the interictal period of migraine where attacks can be triggered by normally nonnoxious events and suggests that BDNF-dependent plasticity may contribute to migraine.

Serum levels of adiponectin, CCL3/MIP-1α, and CCL5/RANTES discriminate migraine from tension-type headache patients

OBJECTIVES

Inflammatory molecules and neurotrophic factors are implicated in pain modulation; however, their role in primary headaches is not yet clear. The aim of this study was to compare the levels of serum biomarkers in migraine and tension-type headache.

METHODS

This was a cross-sectional study. We measured serum levels of adiponectin, chemokines, and neurotrophic factors in patients with migraine and tension-type headache. Depression and anxiety symptoms, headache impact and frequency, and allodynia were recorded.

RESULTS

We included sixty-eight patients with migraine and forty-eight with tension-type headache. Cutaneous allodynia (p = 0.035), CCL3/MIP-1α (p = 0.041), CCL5/RANTES (p = 0.013), and ADP (p = 0.017) were significantly higher in migraine than in tension-type headache. The differences occurred independently of anxiety and depressive symptoms, frequency and impact of headache, and the presence of pain.

CONCLUSIONS

This study showed higher CCL3/MIP-1α, CCL5/RANTES, and ADP levels in migraine in comparison with tension-type headache. Our findings suggest distinctive roles of these molecules in the pathophysiology of these primary headaches.

Brain-Derived Neurotrophic Factor Val66Met Gene Polymorphism Impacts on Migraine Susceptibility: A Meta-analysis of Case-Control Studies

Inconclusive results have been reported in studies investigating the association between the brain-derived neurotrophic factor (BDNF) rs6265 polymorphism and migraine. In the present study, we conducted a systematic review and meta-analysis on the published data in order to quantitatively estimate the relationship between rs6265 and migraine susceptibility. A comprehensive search was performed through PubMed, Web of Knowledge, and Cochrane databases up to October 2016. The pooled odds ratio (OR) with the corresponding 95% confidence interval (CI) was calculated to estimate the strength of the association with rs6265 under an additive, dominant, or recessive model of inheritance. A total of five studies including 1,442 cases and 1,880 controls were identified for the meta-analysis. The pooled data showed an increased risk of migraine for the allelic (OR: 1.17, 95% CI: 1.03–1.34, p = 0.014) or the dominant model of rs6265 (OR: 1.22, 95% CI: 1.05–1.41, p = 0.011). Statistical significance of rs6265 was lost when one single study was excluded from the analysis (dominant OR: 1.17, 95% CI: 1.00–1.38, p = 0.054; allelic OR: 1.14, 95% CI: 0.99–1.31, p = 0.067), suggesting lack of robustness of pooled estimates. When stratified by migraine type, a similar trend of association was detected with both MA and MO, but a statistically significant association of rs6265 was reached only with the MA subtype in the dominant model (OR: 1.22, 95% CI: 1.00–1.47, p = 0.047). The present meta-analysis supports that BDNF rs6265 may act as a genetic susceptibility factor for migraine. Nevertheless, large-scale studies are required to confirm our findings and to assess potential modifiers of the relationship between rs6265 and migraine.

Tumour Necrosis Factor-Α, Interleukin-1 and Interleukin-6 Serum Levels and Its Correlation with Pain Severity in Chronic Tension-Type Headache Patients: Analysing Effect of Dexketoprofen Administration

AIM:

The purpose of this study is to see the effect of Dexketoprofen on TNF-α, IL-1, and IL-6 serum levels in Chronic Tension-Type Headache (CTTH) patients and its correlation with pain severity.

METHOD:

The study subjects were recruited consecutively from the study population. Venous blood was taken at baseline to measure serum levels of TNF-α, IL-1, and IL-6 and after ten consecutive days of Dexketoprofen 25 mg once daily.

RESULTS:

Twenty three subjects participated in this study, 3 male (13.0%) and 20 female (87%). A significant difference between NRS score at baseline and after treatment (4.86 ± 1.82 vs. 1.96 ± 1.40, p = 0.001) was found. No significant difference found between baseline and after treatment TNF-α (1.48 ± 0.65 pg/dl vs. 1.48 ± 0.63 pg/dl, p = 0.963), IL-1 (0.16 ± 0.80 pg/dl vs. 0.26 ± 0.31 pg/dl, p = 0.168) nor IL-6 serum levels (1.06 ± 0.83 pg/dl vs. 1.04 ± 0.81 pg/dl, p = 0.915). A weak negative (R = -0.266) non significant correlation (p = 0.219) was found between NRS score and TNF-α. A positive weak negative (R = 0.221) non significant correlation (p = 0.311) between NRS score and IL-1. NRS score and IL-6 had a negative very weak (R = -0.019) non significant negative correlation (p = 0.931).

CONCLUSIONS:

Dexketoprofen decreased pain intensity significantly (p = 0.001), but had no effect on TNF-α IL-1 nor IL-6 serum levels. NRS score had a weak and non significant negative correlation with TNF-α, a weak and non significant positive correlation with IL-1, and a very weak and non significant negative correlation with IL-6 serum levels.

The association between brain-derived neurotrophic factor gene polymorphism and migraine: a meta-analysis

Background

Migraine is a recurrent headache disease related to genetic variants. The brain-derived neurotrophic factor (BDNF) gene rs6265 (Val66Met) and rs2049046 polymorphism has been found to be associated with migraine. However, their roles in this disorder are not well established. Then we conduct this meta-analysis to address this issue.

Methods

PubMed, Web of Science and Cochrane databases were systematically searched to identify all relevant studies. Odds ratio (OR) with corresponding 95% confidence interval (CI) was used to estimate the strength of association between BDNF gene rs6265 and rs2049046 polymorphism and migraine.

Results

Four studies with 1598 cases and 1585 controls, fulfilling the inclusion criteria were included in our meta-analysis. Overall data showed significant association between rs6265 polymorphism and migraine in allele model (OR = 0.86, 95%CI: 0.76–0.99, p = 0.03), recessive model (OR = 0.84, 95%CI: 0.72–0.98, p = 0.03) and additive model (GG vs GA: OR = 0.85, 95%CI: 0.72–1.00, p = 0.04), respectively. We also found significant association between rs2049046(A/T) polymorphism and migraine in allele model (OR = 0.88, 95%CI: 0.79–0.98, p = 0.02), recessive model (OR = 0.80, 95%CI: 0.67–0.96, p = 0.02) and additive model (AA vs TT: OR = 0.72, 95%CI: 0.57–0.92, p = 0.008; AA vs AT: OR = 0.81, 95%CI: 0.67–0.99, p = 0.03), respectively.

Conclusion

Our meta-analysis suggested that BDNF rs6265 and rs2049046 polymorphism were associated with common migraine in Caucasian population. Further studies are awaited to update this finding in Asian population and other types of migraine.

Involvement of BDNF/TrkB and ERK/CREB axes in nitroglycerin-induced rat migraine and effects of estrogen on these signals in the migraine

Migraine is a highly prevalent headache disorder, especially in women. Brain-derived neurotrophic factor (BDNF) and its receptor tropomyosin receptor kinases (TrkB), as well as extracellular signal-regulated kinase (ERK) and its downstream target c-AMP-responsive element binding protein (CREB) are strongly associated with the transmission of nociceptive information. However, the involvement of these substances in migraine has rarely been examined. In the present study, intraperitoneal injection of nitroglycerin (NTC) successfully induced rat migraine attack, as evidenced by behavioral testing. The location and abundance of these substances in the migraine model were determined by immunohistochemistry, real-time polymerase chain reaction (RT-PCR), western blot and enzyme-linked immunosorbant assays (ELISA). Results showed that BDNF, TrkB, phosphor(p)-ERK and p-CREB were up-regulated in the brain neurons of both male and female rats with NTG-induced migraine compared to non-migraine control, whereas their expression levels were decreased in headache-free intervals of the migraine compared to migraine attacks. Estrogen is an important contributor to migraine. Female ovariectomized rats showed significant reduction in the expression of BDNF, TrkB, p-CREB and p-ERK in both attacks and intervals of NTG-induced migraine, relative to rats that have their ovaries. But, intraperitoneal administration of exogenous estrogen recovered their expression in ovariectomized rats. Collectively, this study unveiled a positive correlation of BDNF/TrkB and ERK/CREB axes in NTG-induced migraine and promoting effects of estrogen on their signals in the migraine. These findings contribute to further understanding the pathogenesis of migraine in the molecular basis.

Summary: This study unveiled a positive correlation of BDNF/TrkB and CREB/ERK axes in NTG-induced migraine and the promoting effects of estrogen on their signals in the migraine.

Effect of Deep Intramuscular Stimulation and Transcranial Magnetic Stimulation on Neurophysiological Biomarkers in Chronic Myofascial Pain Syndrome

OBJECTIVE

The aim was to assess the neuromodulation techniques effects (repetitive transcranial magnetic stimulation [rTMS] and deep intramuscular stimulation therapy [DIMST]) on pain intensity, peripheral, and neurophysiological biomarkers chronic myofascial pain syndrome (MPS) patients.

DESIGN

Randomized, double blind, factorial design, and controlled placebo-sham clinical trial.

SETTING

Clinical trial in the Laboratory of Pain and Neuromodulation at Hospital de Clínicas de Porto Alegre (NCT02381171).

SUBJECTS

We recruited women aged between 19- and 75-year old, with MPS diagnosis.

METHODS

Patients were randomized into four groups: rTMS + DIMST, rTMS + sham-DIMST, sham-rTMS + DIMST, sham-rTMS + sham-DIMST; and received 10 sessions for 20 minutes each one (rTMS and DIMST). Pain was assessed by visual analogue scale (VAS); neurophysiological parameters were assessed by transcranial magnetic stimulation; biochemical parameters were: BDNF, S100β, lactate dehydrogenase, inflammatory (TNF-α, IL6, and IL10), and oxidative stress parameters.

RESULTS

We observed the pain relief assessed by VAS immediately assessed before and after the intervention (P < 0.05, F(1,3)= 3.494 and F(1,3)= 4.656, respectively); in the sham-rTMS + DIMST group and both three active groups in relation to sham-rTMS + sham-DIMST group, respectively. There was an increase in the MEP after rTMS + sham-DIMST (P < 0.05). However, there was no change in all-peripheral parameters analyzed across the treatment (P > 0.05).

CONCLUSION

Our findings add additional evidence about rTMS and DIMST in relieving pain in MPS patients without synergistic effect. No peripheral biomarkers reflected the analgesic effect of both techniques; including those related to cellular damage. Additionally, one neurophysiological parameter (increased MEP amplitude) needs to be investigated.

Neurotrophins and Migraine

Neurotrophins (NTs) have been implicated in generation and modulation of nociceptive pathways. Change in NTs levels is associated with painful conditions and neurological diseases such as migraine. Currently, it is generally recognized that migraine headaches result from the activation and sensitization of trigeminal sensory afferent fibers leading to neuropeptides release such as calcitonin gene-related peptide (CGRP) and substance P (SP). This triggers an inflammatory cascade causing a neurogenic inflammation. The agents responsible for trigeminal activation and release of neuropeptides are still unclear. It is known that the transient receptor potential vanilloid receptor-1 (TRPV1) is an important mediator of CGRP and SP release. TRPV1 is closely associated with tyrosine receptors kinases (Trk), which are NTs receptors. NTs can act on TRPV1 increasing its sensitivity to painful stimuli, therefore predisposing to hyperalgesia. Upregulation of ion channels and pain receptors in dorsal root ganglion neurons may be alternative mechanisms by which NTs contribute to pain development. Only a few studies have been performed to investigate the role of NTs in migraine. These studies have reported changes in NTs levels in migraine patients either during the migraine attack or in free-headache periods.

Neurotrophic factors in tension-type headache

Neurotrophic factors (NF) are involved in pain regulation and a few studies have suggested that they may play a pathophysiological role in primary headaches. The aim of this study was to investigate NF levels in patients with tension type headache (TTH). We carried out a cross sectional study including 48 TTH patients and 48 age and gender matched controls. Beck Depression and Anxiety Inventories, and Headache Impact Test were recorded. Serum levels of NF were determined by ELISA. There were not significant differences between NF levels between TTH patients and controls. Patients with chronic and episodic TTH had not significant differences in NF levels. The presence of headache at the time of evaluation did not significantly alter the levels of NF. Depression and anxiety scores as well as headache impact did not correlate with NF levels. Our study suggest that the serum levels of NF are not altered in TTH.

Meningeal afferent signaling and the pathophysiology of migraine

Migraine is the most common neurological disorder. Attacks are complex and consist of multiple phases but are most commonly characterized by intense, unilateral, throbbing headache. The pathophysiology contributing to migraine is poorly understood and the disorder is not well managed with currently available therapeutics, often rendering patients disabled during attacks. The mechanisms most likely to contribute to the pain phase of migraine require activation of trigeminal afferent signaling from the cranial meninges and subsequent relay of nociceptive information into the central nervous system in a region of the dorsal brainstem known as the trigeminal nucleus caudalis. Events leading to activation of meningeal afferents are unclear, but nerve endings within this tissue are mechanosensitive and also express a variety of ion channels including acid-sensing ion channels and transient receptor-potential channels. These properties may provide clues into the pathophysiology of migraine by suggesting that decreased extracellular pH and environmental irritant exposure in the meninges contributes to headache. Neuroplasticity is also likely to play a role in migraine given that attacks are triggered by routine events that are typically nonnoxious in healthy patients and clear evidence of sensitization occurs during an attack. Where and how plasticity develops is also not clear but may include events directly on the afferents and/or within the TNC. Among the mediators potentially contributing to plasticity, calcitonin gene-related peptide has received the most attention within the migraine field but other mechanisms may also contribute. Ultimately, greater understanding of the molecules and mechanisms contributing to migraine will undoubtedly lead to better therapeutics and relief for the large number of patients across the globe who suffer from this highly disabling neurological disorder.

Migraine is associated with altered levels of neurotrophins

Neurotrophic factors have been implicated in hyperalgesia and peripheral levels of these molecules were altered in behavioral and neurological disorders. The objectives of this study were to assess neurotrophic factors levels in migraine patients in comparison with controls, and to investigate whether there was any association between them and clinical parameters. This was a cross-sectional study. We measured serum levels of neurotrophin family members - nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin 3 and 4/5 (NT3 and NT4/5) - and glial cell line-derived factor (GDNF) in patients suffering from migraine and matched controls. One hundred forty-one people were enrolled in this study, seventy-one were migraine patients and seventy were controls. Migraine patients showed more depressive and anxiety symptoms than control individuals as assessed, respectively, by the Beck Depression Inventory (BDI) and the Beck Anxiety Inventory. Chronic and episodic migraine patients showed higher NT4/5 levels than control individuals (P=0.001). Patients with chronic migraine had lower levels of BDNF that were not influenced by the presence of depressive symptoms (P=0.02). This is the first report to evaluate NT3 and NT-4/5 levels in migraine patients. Our findings suggest a possible role of neurotrophic factors in migraine pathophysiology.

Increased serum levels of interleukin-8 in patients with tension-type headache

Background and objectives

The pathophysiology of tension-type headache is not well understood. Increased peripheral levels of pro-inflammatory cytokines may act as mediators of several chronic pain disorders. The aim of the present study was to investigate the peripheral levels of chemokines in patients with tension-type headache.

Methods

This was a cross sectional study evaluating serum levels of chemokines in age and sex-matched tension-type headache patients, ictally and interictally, and control participants. Beck Depression and Anxiety Inventories were recorded. Serum levels of monocyte chemoattractant protein-1, macrophage inflammatory protein 1α, regulated on activation, normal T cell expressed and secreted, eotaxin, eotaxin-2, interleukin-8, interferon gamma induced protein-10 were measured by enzyme-linked immunosorbent assay.

Results

A total of 96 participants (48 tension-type headache, 48 controls) were included. Interleukin-8 levels were significantly increased in patients with tension-type headache when compared to controls (413.8 (123.4–1756.3) and 329 (107.8–955.6), respectively, P = 0.025). Anxiety and depression scores were higher in patients with tension-type headache but interleukin-8 increase in tension-type headache patients persisted after controlling for anxiety and depression symptoms. Patients with headache at the time of assessment had increased monocyte chemoattractant protein-1 levels when compared with patients without headache (2809.3 (1101–6122.2) and 1630.2 (669.3–31056.8), respectively P = 0.026). Patients with episodic and chronic tension-type headache had no significant differences in serum chemokines levels.

Conclusion

Interleukin-8 was increased in tension-type headache and monocyte chemoattractant protein-1 was higher in tension-type headache patients with headache, suggesting that pro-inflammatory mechanisms may participate in tension-type headache pathophysiology.