Association between Helicobacter pylori infection and migraine: A meta-analysis

A Narrative Review of Intestinal Microbiota's Impact on Migraine with Psychopathologies

Migraine is a common and debilitating neurological disorder characterized by the recurrent attack of pulsating headaches typically localized on one side of the head associated with other disabling symptoms, such as nausea, increased sensitivity to light, sound and smell and mood changes. Various clinical factors, including the excessive use of migraine medication, inadequate acute treatment and stressful events, can contribute to the worsening of the condition, which may evolve to chronic migraine, that is, a headache present on >15 days/month for at least 3 months. Chronic migraine is frequently associated with various comorbidities, including anxiety and mood disorders, particularly depression, which complicate the prognosis, response to treatment and overall clinical outcomes. Emerging research indicates a connection between alterations in the composition of the gut microbiota and mental health conditions, particularly anxiety and depression, which are considered disorders of the gut-brain axis. This underscores the potential of modulating the gut microbiota as a new avenue for managing these conditions. In this context, it is interesting to investigate whether migraine, particularly in its chronic form, exhibits a dysbiosis profile similar to that observed in individuals with anxiety and depression. This could pave the way for interventions aimed at modulating the gut microbiota for treating difficult-to-manage migraines.

Exploring the Potential Consortium of Migraine and Periodontitis

Objectives

Various researches have shown periodontitis to share common pathophysiological pathways with systemic diseases such as diabetes, cardiovascular diseases, and osteoporosis and recently neurological disorders. This article provides a narrative review summarizing the various linking mechanisms and the nature of association between two multifactorial diseases-periodontitis and migraine.

Materials and Methods

A literature search was performed for articles related to periodontitis and migraine up till the year 2023 which yielded totally 14 articles. There were only three randomized controlled clinical trials; therefore, we were unable to conduct a systematic review and focused on a narrative review. The keywords searched were "migraine", "periodontitis" and "biomarkers" in PubMed/Medline, Web of Science, and Embase databases. Any article related to the association of periodontitis and migraine and the dental management of subjects with headache disorders were included and studies with migraine and other dental diseases were excluded.

Results

It is found that the occurrence of periodontitis and migraine are associated with each other. There is reasonable evidence to believe that periodontitis and migraine are linked by direct and indirect mechanisms which can eventually lead to chronic inflammatory conditions like periodontitis worsening neurovascular conditions such as migraine. However, upon detailed analysis it was found that the strength of association is weak owing to the presences of various common confounding and risk factors.

Conclusions

The association between periodontitis and migraine cannot be denied, however, not all the criteria are fulfilled while examining the nature of association and future long-term studies are required to prove the same. Clinical Relevance. Various studies have reported poor periodontal health in patients with migraine. The risk of exacerbation of migraine also increases in subject undergoing dental therapy if the triggering factors are manipulated. Hence, knowing the precise pathophysiologic mechanisms linking both the diseases would be favorable in planning treatment protocols for subjects with migraine.

Migraine and the microbiota. Can probiotics be beneficial in its prevention? - a narrative review

Migraine is a recurrent disease of the central nervous system that affects an increasing number of people worldwide causing a continuous increase in the costs of treatment. The mechanisms underlying migraine are still unclear but recent reports show that people with migraine may have an altered composition of the intestinal microbiota. It is well established that the gut-brain axis is involved in many neurological diseases, and probiotic supplementation may be an interesting treatment option for these conditions. This review collects data on the gastrointestinal and oral microbiota in people suffering from migraine and the use of probiotics as a novel therapeutic approach in its treatment.

Helicobacter pylori infection in migraine headache: a true association or an innocent bystander?

Much concern was directed towards the relationship between migraine and Helicobacter pylori (H. pylori) infection. Some researchers reported a strong association. Meanwhile, others have indicated totally negative results. The aim of this work was to clarify the association between migraine headaches and both H. pylori infection and Gastrointestinal (GIT) symptoms and to study their impact on the frequency and severity of migraine headache attacks.

This is a case control study conducted on 77 migraine patients and 77 healthy controls. History was taken from the included patients regarding the frequency of migraine headache attacks/month and GIT symptoms including dyspepsia, flatulence, weight loss, and epigastric pain. Migraine Disability Assessment Test (MIDAS) and Visual Analogue Scale (VAS) were used for assessment of migraine severity. Helicobacter pylori was detected in the stool of the included patients and controls.

There was a significantly higher prevalence of infection with H. pylori in migraine patients [77.9% (n = 60)] than control group [50.6% (n = 39)] (P-value˂ 0.001, Odds ratio= 3.439, 95% CI =1.708 - 6.923). The prevalence of dyspepsia, flatulence, and epigastric pain. was significantly higher in migraine patients in comparison to control group (P-value= 0.003, 0.017, 0.006 respectively). There was no effect of infection with H. pylori or presence of GIT symptoms on frequency of migraine attacks, MIDAS or VAS scores.

GIT symptoms and H. pylori infection are more prevalent in patients with migraine compared to controls, however, they might not have an impact on the frequency or severity of migraine headache attacks.

Association Between Migraine and Gastrointestinal Disease in Pediatric Patients: A Propensity Score Weighting Approach

Purpose

Migraine is a neurological disorder affecting pediatric patients of all age groups, with a prevalence ranging from approximately 5% to 15%. It significantly impacts the quality of life in children and adolescents, potentially hampering their learning abilities, school performance, and daily activities. This study investigated the association between migraine and several prevalent gastrointestinal (GI) diseases in pediatric patients.

Patients and Methods

We analyzed the Health Insurance Review and Assessment Service Pediatric Patient Sample (HIRA-PPS) dataset from South Korea. Propensity scores based on patient characteristics (age, sex, and insurance type) were employed through the inverse probability of treatment weighting (IPTW) in binary logistic regression. We included gastroesophageal disease (GERD), peptic ulcer disease (PUD), gastritis, dyspepsia, irritable bowel syndrome (IBS), and inflammatory bowel disease (IBD) as GI diseases.

Results

A total of 683,347 patients from the HIRA dataset were included in the study. After IPTW adjustment, the prevalence of GI diseases among pediatric patients with migraine remained significantly increased (OR 4.15; 95% CI 4.12-4.18). Migraine patients showed higher prevalence rates for all six individual GI diseases, with GERD (OR 4.11; 95% CI 4.05-4.16) and IBS (OR 3.79; 95% CI 3.74-3.84) showing the highest associations. We also confirmed a progressively increasing association between the presence of diagnosed migraine and GI diseases.

Conclusion

This study highlights a strong association between pediatric migraine and GI diseases, even after adjusting for patient characteristics. The elevated prevalence of various GI diseases in migraine patients suggests the need for comprehensive approaches to their prevention and treatment.

The Gut-brain Connection and Episodic Migraine: an Update

PURPOSE OF REVIEW

Historical evidence suggests a shared underlying etiology for migraine and gastrointestinal (GI) disorders that involves the gut-brain axis. Here we provide narrative review of recent literature on the gut-brain connection and migraine to emphasize the importance of tailoring treatment plans for patients with episodic migraine who experience GI comorbidities and symptoms.

RECENT FINDINGS

Recent population-based studies report the prevalence of migraine and GI disorders as comorbidities as well as overlapping symptomology. American Headache Society (AHS) guidelines have integrated GI symptoms as part of migraine diagnostic criteria and recommend nonoral therapies for patients with GI symptoms or conditions. Nasal delivery is a recommended nonoral alternative; however, it is important to understand potential adverse events that may cause or worsen GI symptoms in some patients due to the site of drug deposition within the nasal cavity with some nasal therapies. Lastly, clinical perspectives emphasize the importance of identifying GI symptoms and comorbidities in patients with episodic migraine to best individualize migraine management. Support for an association between the gut-brain axis and migraine continues to prevail in recent literature; however, the relationship remains complex and not well elucidated. The presence of GI comorbidities and symptoms must be carefully considered when making treatment decisions for patients with episodic migraine.

Association of Helicobacter pylori with migraine headaches and the effects of this infection and its eradication on the migraine characteristics in adults: A comprehensive systematic review and meta-analysis

BACKGROUND

Migraine is one of the most common neurological disorders that can severely overshadow people's quality of life, and Helicobacter pylori infection is a health problem in different societies. During the last two decades, many original studies have been conducted on the various aspects of the relationship between these two disorders; however, they have reported different and sometimes contradictory results.

METHODS

This study was conducted based on the PRISMA protocol. We performed a comprehensive literature search in the online databases up to May 2023, and 22 studies that contained original data on the relationship between H. pylori infection and migraine headaches in adults were included. For performing the meta-analysis, we calculated the odds ratios (OR) and 95% confidence intervals (CI), using a random-effects model, and to determine the possible causes of heterogeneity, we conducted a subgroup meta-analysis.

RESULTS

The overall OR for the association of H. pylori infection and migraine headaches through 493,794 evaluated individuals was 2.80 [95% CI = 1.75-4.48; I2  = 89.20, p < 0.01], which reveals a statistically significant association between these disorders. It was found that the studies that were conducted in Asian regions and the recently published ones have clearly shown a higher association between migraine and H. pylori infection. On the other hand, migraine patients who are infected with H. pylori have similar signs and symptoms as H. pylori-negative migraineurs; meanwhile, the clinical trials conducted in this field strongly emphasize the benefits of eradicating H. pylori infection in migraine patients and have estimated its effectiveness in improving migraine headaches equivalent to current common migraine treatments. Furthermore, it was reported that white matter lesions were 2.5-fold higher on brain MRI in patients with H. pylori-positive migraine compared with H. pylori-negative migraineurs; however, the evidence does not support the role of oxidative stress in patients suffering from H. pylori infection and migraine and refuses the role of Cag-A-positive strains of H. pylori in migraine headaches.

CONCLUSION

According to the currently available data, it seem reasonable that patients with a definite diagnosis of migraine who also suffer from gastrointestinal problems, undergo the H. pylori detection tests and if the evaluations are positive, H. pylori eradication treatment can be considered even before any migraine treatment.

Migraine as a Disease Associated with Dysbiosis and Possible Therapy with Fecal Microbiota Transplantation

Migraine is a painful neurological condition characterized by severe pain on one or both sides of the head. It may be linked to changes in the gut microbiota, which are influenced by antibiotic use and other factors. Dysbiosis, which develops and persists as a result of earlier antibiotic therapy, changes the composition of the intestinal flora, and can lead to the development of various diseases such as metabolic disorders, obesity, hematological malignancies, neurological or behavioral disorders, and migraine. Metabolites produced by the gut microbiome have been shown to influence the gut-brain axis. The use of probiotics as a dietary supplement may reduce the number and severity of migraine episodes. Dietary strategies can affect the course of migraines and are a valuable tool for improving migraine management. With fecal microbiota transplantation, gut microbial restoration is more effective and more durable. Changes after fecal microbiota transplantation were studied in detail, and many data help us to interpret the successful interventions. The microbiological alteration of the gut microflora can lead to normalization of the inflammatory mediators, the serotonin pathway, and influence the frequency and intensity of migraine pain.

A causal effects of gut microbiota in the development of migraine

BACKGROUND

The causal association between the gut microbiome and the development of migraine and its subtypes remains unclear.

METHODS

The single nucleotide polymorphisms concerning gut microbiome were retrieved from the gene-wide association study (GWAS) of the MiBioGen consortium. The summary statistics datasets of migraine, migraine with aura (MA), and migraine without aura (MO) were obtained from the GWAS meta-analysis of the International Headache Genetics Consortium (IHGC) and FinnGen consortium. Inverse variance weighting (IVW) was used as the primary method, complemented by sensitivity analyses for pleiotropy and increasing robustness.

RESULTS

In IHGC datasets, ten, five, and nine bacterial taxa were found to have a causal association with migraine, MA, and MO, respectively, (IVW, all P < 0.05). Genus.Coprococcus3 and genus.Anaerotruncus were validated in FinnGen datasets. Nine, twelve, and seven bacterial entities were identified for migraine, MA, and MO, respectively. The causal association still exists in family.Bifidobacteriaceae and order.Bifidobacteriales for migraine and MO after FDR correction. The heterogeneity and pleiotropy analyses confirmed the robustness of IVW results.

CONCLUSION

Our study demonstrates that gut microbiomes may exert causal effects on migraine, MA, and MO. We provide novel evidence for the dysfunction of the gut-brain axis on migraine. Future study is required to verify the relationship between gut microbiome and the risk of migraine and its subtypes and illustrate the underlying mechanism between them.

Association Between Helicobacter pylori Infection and Migraine: A Systematic Review

Migraine is a highly debilitating disease affecting humans worldwide. Despite having known this disease for a long time, not many studies have been done to search for a chronic infectious cause of migraine. The goal of this study was to look for an association between migraine and Helicobacter pylori infection. Following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) standards, we conducted the analysis and literature search using PubMed, Google Scholar and Cochrane databases. After applying the inclusion and exclusion criteria, the search technique produced a total of 10 articles including one cross-sectional study, two randomized controlled trials (RCTs), one cohort study, five case-control studies and one meta-analysis. Analysis of these studies revealed that there could be an association between Helicobacter pylori infection and migraine, especially in the Asian population. However, the mechanism by which the infection could possibly cause this extra-gastric disorder needs further research and analysis.

Systematic review and meta-analysis of calculating degree of comorbidity of irritable bowel syndrome with migraine

BACKGROUND

Irritable bowel syndrome (IBS) and migraines are often comorbid each other. These disorders are likely to be bidirectionally linked through the gut-brain axis and share several underlying mechanisms including central nervous system sensitization. However, quantitative analysis of comorbidity was not reported enough. The aim of this systematic review and meta-analysis was to calculate the present degree of comorbidity of these two disorders.

METHODS

A literature search was performed searching for articles describing IBS or migraine patients with the same inverse comorbidity. Pooled odds ratios (ORs) or hazard ratios (HRs) with 95% confidence intervals (CIs) were then extracted. The total effect estimates were determined and presented by random effect forest plots for the group of articles with IBS patients with migraine and the group of articles on migraine sufferers with comorbid IBS separately. The average results of these plots were compared.

RESULTS

The literature search resulted in initial 358 articles and final 22 articles for the meta-analysis. The total OR values obtained were 2.09 [1.79 - 2.43] in IBS with comorbid migraine or headache, 2.51 [1.76 - 3.58] for migraineurs with comorbid IBS and an overall HR of 1 .62 [1.29 - 2.03] was found for cohort studies of migraine sufferers with comorbid IBS. A similar expression of a selection of other comorbidities was found in IBS and migraine patients, especially for depression and fibromyalgia a strong similarity was found in their expression rate.

CONCLUSIONS

This systematic review with meta-analysis was the first to combine data on IBS patients with comorbid migraine and migraineurs with comorbid IBS. The fact that closely related existential rates were observed between these two groups should be used as motivation for future research to further investigate these disorders for why this similarity occurs. Mechanisms involved in central hypersensitivity such as genetic risk factors, mitochondrial dysfunction and microbiota are particularly good candidates. Experimental designs in which therapeutic methods for these conditions can be exchanged or combined may also lead to the discovery of more efficient treatment methods.

Helicobacter pylori Infection in Children: A Possible Reason for Headache?

(1) Background: The correlation between infection with Helicobacter pylori (H. pylori) and headache has been argued and explored for a long time, but a clear association between the simultaneous presence of the two in children has not been established yet. In this study, we aimed to explore this relationship in children from the Northeast region of Romania. (2) Methods: A retrospective study exploring the correlation between children having H. pylori infection and headache or migraine was conducted on a batch of 1757 children, hospitalized over 3 years in a pediatric gastroenterology department in Northeast Romania. (3) Results: A total of 130 children of both sexes had headache. From 130 children, 54 children (41.5%) also presented H. pylori infection. A significant association between headache and H. pylori infection (χ2; p < 0.01) was noticed. (4) Conclusions: More studies are needed on this relationship, and we emphasize the importance of further analyses, as they present great clinical importance for both prompt diagnosis and treatment.

[The state of the oropharyngeal microbiome in patients with migraine]

OBJECTIVE

To determine a role of changes in the oropharyngeal microbiome in the development and clinical manifestations of migraine.

MATERIAL AND METHODS

Seventy patients with migraine, aged 21-56 years, and 15 healthy subjects matched for age and sex were examined using headache diary, MIDAS and VAS, the Gastrointestinal Symptom Rating Scale (GSRS), microbiological smear examination from the mucous membrane of the posterior wall of the oropharynx with evaluation by the method of mass spectrometry of microbial markers (MSMM) with determination of 57 microorganisms.

RESULTS

The following changes in the oropharynx of individuals with migraine compared with the group of healthy individuals (control group) were found: a) a significant increase in the content of markers of resident (conditionally pathogenic) microorganisms characteristic of chronic diseases of the upper respiratory tract (strepto- and staphylococci); b) the appearance of markers of transient microorganisms normally absent, characteristic of the intestinal microflora (clostridia, gram-negative rods, enterobacteria, anaerobes); c) the appearance of viral markers of cytomegaloviruses, Herpes group, Epstein-Barr; d) a significant decrease in the content of bifidobacteria and lactobacilli). All people with migraine had a history or were found on examination to have chronic diseases of the upper respiratory tract (sinusitis in 48%, pharyngitis in 43%, tonsillitis in 25% of people), and gastrointestinal diseases. Dyspepsia was the most frequent and pronounced of the gastrointestinal syndromes on the GSRS in people with migraine (87%). This corresponds to the data on the extremely frequent occurrence of IBS (70% of patients) and other gastrointestinal pathology obtained from the patient history.

CONCLUSION

In our work, the microbiota of the oropharynx in patients with migraine was studied for the first time using a new MSMM method. Disturbance of the oropharyngeal microbiome compared to the norm was detected in 100% of people with migraine. The changes characteristic of most patients included a significant decrease in the content of normal flora, an increase in the concentration of conditionally pathogenic microorganisms and the appearance of pathogenic microflora characteristic of chronic diseases of the upper respiratory tract and gastrointestinal tract, which may indicate their role in the pathogenesis of migraine.

Associations between the Gut Microbiome and Migraines in Children Aged 7-18 Years: An Analysis of the American Gut Project Cohort

BACKGROUND

The gut microbiome seems to play a role in migraines through increasing intestinal epithelial permeability and pro-inflammatory processes. The associations between the gut microbiome and migraines are uncertain in children.

AIM

The purpose of this quantitative study was to examine the associations between the gut microbiome and migraines in children aged 7-18 years from the American Gut Project (AGP).

METHOD

A cohort of children aged 7-18 years from the AGP was analyzed. 16S rRNA V4 gene sequences for the gut microbiome, migraines, and demographics were obtained from the AGP Public Repository. After quality control of 16S rRNA gene sequences, α-diversity (Shannon, Faith's_PD, and evenness) and β-diversity metrics (Bray-Curtis and weighted-UniFrac distances), taxonomy, and abundance analyses were implemented using QIIME 2.

RESULTS

In total, 381 children (341 without migraines; 40 with professional or self-diagnosed migraines) were analyzed with a mean age of 11.5 years. Compared with those without migraines, children with migraines showed lower estimates in Shannon and Faith's_PD (p < .01). Both Bray-Curtis and weighted-UniFrac distances displayed the gut microbial dissimilarities between these two groups (p = .001). Children with migraines had higher abundances in genus of phylum Bacteroidetes (Bacteroides, Parabacteroides, Odoribacter), Actinobacteria (Eggerthella, Varibaculum), Firmicutes (SMB53, Lachnospira, Dorea, Veillonella, Anaerotruncus, Butyricicoccus, Coprobacillus, Eubacterium), and Proteobacteria (Sutterella) than children without migraines.

CONCLUSIONS

Associations of the gut microbiome diversity and abundances with migraines in children indicated potential biological mechanisms of migraines. Future work needs to confirm our findings in children.

Comorbidities in patients with migraine in Japan: a cross-sectional study using data from National Health and Wellness Survey

OBJECTIVES

This study aims to examine the association between migraine and various psychiatric and somatic comorbidities in Japan.

DESIGN

Cross-sectional study using existing data of the 2017 Japan National Health and Wellness Survey (NHWS).

SETTING

Nationally representative sample of persons (in terms of age and gender) living in the general community aged 18 years or older in Japan.

PARTICIPANTS

Out of a sample of 30 001 NHWS respondents, 378 respondents were identified as migraine patients and 25 209 were identified as non-migraine patients. After propensity score (PS) matching (1:4), 1512 matched non-migraine respondents were identified.

PRIMARY AND SECONDARY OUTCOME MEASURES

Prevalence and PS-matched prevalence ORs (PORs) were assessed for each psychiatric and somatic comorbidity among migraine patients and matched non-migraine respondents (including migraine patients with less than 15 monthly headache days (MHDs) and migraine patients with more than 15 MHDs).

RESULTS

Migraine patients were predominately female and had significantly higher prevalence than matched non-migraine respondents to have psychiatric and somatic comorbidities. Psychiatric comorbidities with >5% prevalence among migraine patients included depression, post-traumatic stress disorder and anxiety disorders, while gastrointestinal disorders were the most prevalent somatic comorbidity category. Other somatic comorbidities included allergies, insomnia, premenstrual syndrome and anaemia. Migraine patients with more than 15 MHDs tended to have higher point estimates for POR.

CONCLUSION

Psychiatric and somatic conditions were more prevalent in migraine patients than matched non-migraine respondents, some being novel associations not previously reported in Japan. This study provided insights on comorbidities, which could complicate care, clinical practice and outcomes among migraine patients.

On the Association between Gastrointestinal Symptoms and Extragastric Manifestations

The aim of this study was to investigate the relationship between gastrointestinal (GI) symptoms and extragastric manifestations such as headache, fatigue, and dizziness. A prospective cohort study was conducted in a tertiary hospital in Athens, where patients with GI problems and extragastric symptoms were treated only for their GI problems, and improvement in extragastric manifestations was recorded. Inclusion criteria were an age older than 18 years, the presence of at least one of the three extragastric symptoms investigated in this study (headache, dizziness, and fatigue), and the concomitant presence of at least one gastrointestinal symptom (e.g., nausea, belching, abdominal tenderness, epigastric pain, halitosis, flatulence, diarrhea, bad odor of flatulence, flatulence, and constipation). A standardized questionnaire was used to collect demographic data (such as age, weight, and height), patients' symptoms, laboratory findings (gastric biopsy, gastroscopy, and colonoscopy), and intensity/frequency of GI and extragastric symptoms. Statistically significant associations were found between GI symptoms (nausea, constipation, halitosis, and belching) and dizziness, fatigue, and headache (frequency, intensity, and duration). Treatment of GI problems resulted in a significant improvement in extragastric symptoms within one month of treatment initiation. It should be emphasized that the actual reason for the improvement in extragastric symptoms was solely the resolution of the GI problems, as patients did not receive specific treatments for headache, dizziness or fatigue, or other changes in daily life. This study demonstrates the association between extragastric manifestations and GI disorders.

Relationship between Helicobacter pylori infection and white matter lesions in patients with migraine

Background/aim

White matter lesions (WML) are more frequently observed in migraine patients than in the average population. Associations between Helicobacter pylori (H. pylori) infection and different extraintestinal pathologies have been identified. Here, we aimed to investigate the association between H. pylori infection and WML in patients diagnosed with episodic migraine.

Materials and methods

A retrospective study was conducted with 526 subjects with a diagnosis of episodic migraine. Hyperintensity of WML had been previously evaluated in these patients with brain magnetic resonance imaging (MRI) examinations. Previous endoscopic gastric biopsy histopathological examination of the same patients and reports on H. pylori findings were recorded. The demographic characteristics of the patients, such as age, gender and chronic systemic diseases such as hypertension and diabetes mellitus (DM) were recorded. Statistical evaluation was made.

Results

Evaluation was made among 526 migraine patients who met the inclusion criteria, comprising 397 (75.5%) females and 129 (24.5%) males with a mean age of 45.57 ± 13.46 years (range, 18–69 years). WML was detected on brain MRI in 178 (33.8%) patients who were also positive for H. pylori (p <  0.05). Subjects who are H. pylori-positive with migraine, WML were observed at a 2.5-fold higher incidence on brain MRI (odds ratio: 2.562, 95% CI 1.784–3.680). WML was found to be more significant in patients with hypertension and migraine than those without (p <  0.001). Older age was also found to be associated with WML (OR = 1.07, 95% CI: 0.01–0.04, p <  0.001). The age (p <  0.001), H. pylori (p <  0.001), hypertension (p <  0.001), and hypertension + DM (p <  0.05), had significant associations in predicting WML according to the multivariate logistic regression analysis. The presence of hypertension had a higher odds ratio value than the other variables.

Conclusion

It was concluded that H. pylori infection, as a chronic infection, can be considered a risk factor in developing WML in subjects with migraine.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02715-0.

Migraine: A Review on Its History, Global Epidemiology, Risk Factors, and Comorbidities

Migraine affects more than one billion individuals each year across the world, and is one of the most common neurologic disorders, with a high prevalence and morbidity, especially among young adults and females. Migraine is associated with a wide range of comorbidities, which range from stress and sleep disturbances to suicide. The complex and largely unclear mechanisms of migraine development have resulted in the proposal of various social and biological risk factors, such as hormonal imbalances, genetic and epigenetic influences, as well as cardiovascular, neurological, and autoimmune diseases. This review presents a comprehensive review of the most up-to-date literature on the epidemiology, and risk factors, as well as highlighting the gaps in our knowledge.

Kynurenine Pathway of Tryptophan Metabolism in Migraine and Functional Gastrointestinal Disorders

Migraine, the leading cause of disability in the population aged below 50, is associated with functional gastrointestinal (GI) disorders (FGIDs) such as functional nausea, cyclic vomiting syndrome, and irritable bowel syndrome (IBS). Conversely, changes in intestinal GI transit may cause diarrhea or constipation and are a component of the autonomic symptoms associated with pre- and post-dorsal phases of migraine attack. These mutual relationships provoke a question on a common trigger in migraine and FGIDs. The kynurenine (l-kyn) pathway (KP) is the major route for l-tryptophan (l-Trp) metabolism and transforms l-Trp into several neuroactive compounds. Changes in KP were reported in both migraine and FGIDs. Migraine was largely untreatable, but several drugs approved lately by the FDA, including monoclonal antibodies for calcitonin gene-related peptide (CGRP) and its receptor, create a hope for a breakthrough in migraine treatment. Derivatives of l-kyn were efficient in pain relief with a mechanism including CGRP inhibition. KP products are important ligands to the aryl hydrocarbon receptor (AhR), whose activation is implicated in the pathogenesis of GI and migraine. Toll-like receptors (TLRs) may play a role in migraine and IBS pathogeneses, and KP metabolites detected downstream of TLR activation may be an IBS marker. The TLR4 signaling was observed in initiating and maintaining migraine-like behavior through myeloid differentiation primary response gene 88 (MyD88) in the mouse. The aim of this review is to justify the view that KP modulation may provide common triggers for migraine and FGIDs with the involvement of TLR, AhR, and MyD88 activation.

The role of microbiota-gut-brain axis in neuropsychiatric and neurological disorders

Emerging evidence indicates that the gut microbiota play a crucial role in the bidirectional communication between the gut and the brain suggesting that the gut microbes may shape neural development, modulate neurotransmission and affect behavior, and thereby contribute to the pathogenesis and/or progression of many neurodevelopmental, neuropsychiatric, and neurological conditions. This review summarizes recent data on the role of microbiota-gut-brain axis in the pathophysiology of neuropsychiatric and neurological disorders including depression, anxiety, schizophrenia, autism spectrum disorders, Parkinson's disease, migraine, and epilepsy. Also, the involvement of microbiota in gut disorders co-existing with neuropsychiatric conditions is highlighted. We discuss data from both in vivo preclinical experiments and clinical reports including: (1) studies in germ-free animals, (2) studies exploring the gut microbiota composition in animal models of diseases or in humans, (3) studies evaluating the effects of probiotic, prebiotic or antibiotic treatment as well as (4) the effects of fecal microbiota transplantation.

STOP 301: A Phase 3, open-label study of safety, tolerability, and exploratory efficacy of INP104, Precision Olfactory Delivery (POD® ) of dihydroergotamine mesylate, over 24/52 weeks in acute treatment of migraine attacks in adult patients

Objective

To report the safety, tolerability, exploratory efficacy, and patient acceptability of INP104 for the acute treatment of migraine from the Phase 3 STOP 301 trial.

Background

Dihydroergotamine (DHE) has long been used to treat migraine, but intravenous administration is invasive, frequently associated with adverse events (AEs), and not suitable for at‐home administration. INP104 is an investigational drug device that delivers DHE mesylate to the upper nasal space using a Precision Olfactory Delivery technology and was developed to overcome the shortcomings of available DHE products.

Methods

STOP 301 was an open‐label, 24‐week safety study, with a 28‐week extension period. After a 28‐day screening period where patients used their “best usual care” to treat migraine attacks, patients were given INP104 (1.45 mg) to self‐administer nasally with self‐recognized attacks. The primary objective of this study was to assess safety and tolerability, with a specific focus on nasal mucosa and olfactory function. Exploratory objectives included efficacy assessments of migraine measures and a patient acceptability questionnaire.

Results

A total of 360 patients entered the 24‐week treatment period, with 354 patients dosing at least once. INP104‐related treatment‐emergent AEs were reported by 36.7% (130/354) of patients, and 6.8% (24/354) discontinued treatment due to AEs over 24 weeks. No new safety signals were observed following delivery to the upper nasal space. Pain freedom, the most bothersome symptom freedom, and pain relief at 2 h post‐INP104 were self‐reported by 38.0% (126/332), 52.1% (173/332), and 66.3% (167/252) of patients, respectively. A low recurrence rate at 24 and 48 h was observed (7.1% [9/126] and 14.3% [18/126], respectively). Most patients found INP104 easy to use and preferred it over their current therapy.

Conclusions

INP104 has the potential to deliver rapid symptom relief, without injection, that is well tolerated and suitable for outpatient use. Results suggest INP104 may be a promising treatment for patients with migraine.

Pathophysiological Bases of Comorbidity in Migraine

Despite that it is commonly accepted that migraine is a disorder of the nervous system with a prominent genetic basis, it is comorbid with a plethora of medical conditions. Several studies have found bidirectional comorbidity between migraine and different disorders including neurological, psychiatric, cardio- and cerebrovascular, gastrointestinal, metaboloendocrine, and immunological conditions. Each of these has its own genetic load and shares some common characteristics with migraine. The bidirectional mechanisms that are likely to underlie this extensive comorbidity between migraine and other diseases are manifold. Comorbid pathologies can induce and promote thalamocortical network dysexcitability, multi-organ transient or persistent pro-inflammatory state, and disproportionate energetic needs in a variable combination, which in turn may be causative mechanisms of the activation of an ample defensive system with includes the trigeminovascular system in conjunction with the neuroendocrine hypothalamic system. This strategy is designed to maintain brain homeostasis by regulating homeostatic needs, such as normal subcortico-cortical excitability, energy balance, osmoregulation, and emotional response. In this light, the treatment of migraine should always involves a multidisciplinary approach, aimed at identifying and, if necessary, eliminating possible risk and comorbidity factors.

A link between gastrointestinal disorders and migraine: Insights into the gut-brain connection

Background

Migraine is a complex, multifaceted, and disabling headache disease that is often complicated by gastrointestinal (GI) conditions, such as gastroparesis, functional dyspepsia, and cyclic vomiting syndrome (CVS). Functional dyspepsia and CVS are part of a spectrum of disorders newly classified as disorders of gut–brain interaction (DGBI). Gastroparesis and functional dyspepsia are both associated with delayed gastric emptying, while nausea and vomiting are prominent in CVS, which are also symptoms that commonly occur with migraine attacks. Furthermore, these gastric disorders are comorbidities frequently reported by patients with migraine. While very few studies assessing GI disorders in patients with migraine have been performed, they do demonstrate a physiological link between these conditions.

Objective

To summarize the available studies supporting a link between GI comorbidities and migraine, including historical and current scientific evidence, as well as provide evidence that symptoms of GI disorders are also observed outside of migraine attacks during the interictal period. Additionally, the importance of route of administration and formulation of migraine therapies for patients with GI symptoms will be discussed.

Methods

A literature search of PubMed for articles relating to the relationship between the gut and the brain with no restriction on the publication year was performed. Studies providing scientific support for associations of gastroparesis, functional dyspepsia, and CVS with migraine and the impact these associations may have on migraine treatment were the primary focus. This is a narrative review of identified studies.

Results

Although the association between migraine and GI disorders has received very little attention in the literature, the existing evidence suggests that they may share a common etiology. In particular, the relationship between migraine, gastric motility, and vomiting has important clinical implications in the treatment of migraine, as delayed gastric emptying and vomiting may affect oral dosing compliance, and thus, the absorption and efficacy of oral migraine treatments.

Conclusions

There is evidence of a link between migraine and GI comorbidities, including those under the DGBI classification. Many patients do not find adequate relief with oral migraine therapies, which further necessitates increased recognition of GI disorders in patients with migraine by the headache community.

Increased Risk of Migraine in Patients with Chronic Periodontitis: A Population-Based Cohort Study

Migraine is considered to be a neurovascular disease that manifests as a throbbing headache, possibly caused by the activation of the trigeminovascular system. Several studies have supported the role of inflammation in the pathogenesis of migraine. Chronic periodontitis (CP) is an infectious inflammatory disease triggered by bacterial products evoking an immune response which could result in the destruction of the periodontium. However, little is known about the longitudinal association between CP and migraine. In this study, we designed a nationwide population-based cohort study to investigate the risk of migraine and CP exposure in Taiwan. In total, 68,282 patients with CP were identified from the National Health Insurance Research Database (NHIRD), and 68,282 comparisons were randomly captured and matched by age, sex, monthly income, urbanization and comorbidities. The association between CP exposure and migraine risk was evaluated by Cox proportional hazards regression models. In this study, 785 migraine patients were identified in the CP cohort, and 641 migraine cases were found in the non-CP cohort. The incidence rate of migraine was significantly higher in the CP cohort than the non-CP cohort (adjusted HR: 1.21, 95% CI: 1.09–1.34, p < 0.001) during the 13-year follow-up period. Females had a 2.69-fold higher risk for migraine than males (95% CI: 2.38–3.04, p < 0.001). In summary, CP is associated with an increased risk of subsequent migraine in Taiwan.

The trimebutine effect on Helicobacter pylori-related gastrointestinal tract and brain disorders: A hypothesis

The localization of bacterial components and/or metabolites in the central nervous system may elicit neuroinflammation and/or neurodegeneration. Helicobacter pylori (a non-commensal symbiotic gastrointestinal pathogen) infection and its related metabolic syndrome have been implicated in the pathogenesis of gastrointestinal tract and central nervous system disorders, thus medications affecting the nervous system - gastrointestinal tract may shape the potential of Helicobacter pylori infection to trigger these pathologies. Helicobacter pylori associated metabolic syndrome, by impairing gut motility and promoting bacterial overgrowth and translocation, might lead to brain pathologies. Trimebutine maleate is a prokinetic drug that hastens gastric emptying, by inducing the release of gastrointestinal agents such as motilin and gastrin. Likewise, it appears to protect against inflammatory signal pathways, involved in inflammatory disorders including brain pathologies. Trimebutine maleate also acts as an antimicrobial agent and exerts opioid agonist effect. This study aimed to investigate a hypothesis regarding the recent advances in exploring the potential role of gastrointestinal tract microbiota dysbiosis-related metabolic syndrome and Helicobacter pylori in the pathogenesis of gastrointestinal tract and brain diseases. We hereby proposed a possible neuroprotective role for trimebutine maleate by altering the dynamics of the gut-brain axis interaction, thus suggesting an additional effect of trimebutine maleate on Helicobacter pylori eradication regimens against these pathologies.

Helicobacter pylori infection and eradication: Exploring their impacts on the gastrointestinal microbiota

The rapid development of microbiota research has remolded our view of human physiological and pathological processes. Among all the gastrointestinal microorganisms, Helicobacter pylori (H pylori) is probably the most notorious constituent. Although half of the adults worldwide are infected with H pylori, their clinical manifestations vary widely, suggesting other microorganisms beyond H pylori may play a role in determining clinical outcomes. Recently, many studies have put effort into elucidating the crosstalk within the human microbiota, some of which specifically explored the interplay between H pylori and other gastrointestinal microbial members. In this work, we reviewed these potential interactions. Meanwhile, the impacts of H pylori eradication therapy on gastrointestinal microbial homeostasis were summarized in terms of diversity, composition, functional capacity, and antibiotic resistance.

Gut-brain Axis and migraine headache: a comprehensive review

The terminology "gut-brain axis "points out a bidirectional relationship between the GI system and the central nervous system (CNS). To date, several researches have shown that migraine is associated with some gastrointestinal (GI) disorders such as Helicobacter pylori (HP) infection, irritable bowel syndrome (IBS), and celiac disease (CD). The present review article aims to discuss the direct and indirect evidence suggesting relationships between migraine and the gut-brain axis. However, the mechanisms explaining how the gut and the brain may interact in patients with migraine are not entirely clear. Studies suggest that this interaction seems to be influenced by multiple factors such as inflammatory mediators (IL-1β, IL-6, IL-8, and TNF-α), gut microbiota profile, neuropeptides and serotonin pathway, stress hormones and nutritional substances. Neuropeptides including CGRP, SP, VIP, NPY are thought to have antimicrobial impact on a variety of the gut bacterial strains and thus speculated to be involved in the bidirectional relationship between the gut and the brain. According to the current knowledge, migraine headache in patients harboring HP might be improved following the bacteria eradication. Migraineurs with long headache history and high headache frequency have a higher chance of being diagnosed with IBS. IBS and migraine share some similarities and can alter gut microflora composition and thereby may affect the gut-brain axis and inflammatory status. Migraine has been also associated with CD and the condition should be searched particularly in patients with migraine with occipital and parieto-occipital calcification at brain neuroimaging. In those patients, gluten-free diet can also be effective in reducing migraine frequency. It has also been proposed that migraine may be improved by dietary approaches with beneficial effects on gut microbiota and gut-brain axis including appropriate consumption of fiber per day, adhering to a low glycemic index diet, supplementation with vitamin D, omega-3 and probiotics as well as weight loss dietary plans for overweight and obese patients.

The progress of gut microbiome research related to brain disorders

There is increasing evidence showing that the dynamic changes in the gut microbiota can alter brain physiology and behavior. Cognition was originally thought to be regulated only by the central nervous system. However, it is now becoming clear that many non-nervous system factors, including the gut-resident bacteria of the gastrointestinal tract, regulate and influence cognitive dysfunction as well as the process of neurodegeneration and cerebrovascular diseases. Extrinsic and intrinsic factors including dietary habits can regulate the composition of the microbiota. Microbes release metabolites and microbiota-derived molecules to further trigger host-derived cytokines and inflammation in the central nervous system, which contribute greatly to the pathogenesis of host brain disorders such as pain, depression, anxiety, autism, Alzheimer’s diseases, Parkinson’s disease, and stroke. Change of blood–brain barrier permeability, brain vascular physiology, and brain structure are among the most critical causes of the development of downstream neurological dysfunction. In this review, we will discuss the following parts:

Overview of technical approaches used in gut microbiome studies

Microbiota and immunity

Gut microbiota and metabolites

Microbiota-induced blood–brain barrier dysfunction

Neuropsychiatric diseases

■ Stress and depression

■ Pain and migraine

■ Autism spectrum disorders

Neurodegenerative diseases

■ Parkinson’s disease

■ Alzheimer’s disease

■ Amyotrophic lateral sclerosis

■ Multiple sclerosis

Cerebrovascular disease

■ Atherosclerosis

■ Stroke

■ Arteriovenous malformation

Conclusions and perspectives

Association between H. pylori infection and health Outcomes: an umbrella review of systematic reviews and meta-analyses

OBJECTIVE

Systematic reviews and meta-analyses have revealed the associations between H. pylori infection and various health outcomes. We aimed to evaluate the strength and breadth of evidence on the associations.

DESIGN

Umbrella review of systematic reviews and meta-analyses.

SETTING

No settings.

PARTICIPANTS

No patients involved.

DATA SOURCES

Embase, PubMed, Web of Science, Cochrane Library Databases, CNKI, VIP database and Wangfang database from inception to February 1, 2019.

OUTCOMES MEASURES

Diverse diseases (such as cancer and ischaemic heart disease).

RESULTS

Sixty articles reporting 88 unique outcomes met the eligible criteria. 74 unique outcomes had nominal significance (p<0.05). Of the outcomes with significance, 61 had harmful associations and 13 had beneficial associations. Furthermore, 73% (64) of the outcomes exhibited significant heterogeneity . Of the these meta-analyses, 32 had moderate to high heterogeneity (I²=50%-75%) and 24 had high heterogeneity (I²>75%). Moreover, 20% exhibited publication bias (p<0.1). In addition, 97% of the methodological qualities were rated 'critically low'. 36% of the evidence qualities of outcomes were rated 'low', 56% of the evidence qualities were rated 'very low' and 8% of the evidence qualities were rated 'moderate'. H. pylori infection may be associated with an increased risk of five diseases and a decreased risk of irritable bowel syndrome.

CONCLUSION

Although 60 meta-analyses explored 88 unique outcomes, moderate quality evidence only existed for six outcomes with statistical significance. H. pylori infection may be associated with a decreased risk of irritable bowel syndrome and an increased risk of hypertriglyceridemia, chronic cholecystitis and cholelithiasis, gestational diabetes mellitus, gastric cancer and systemic sclerosis.

TRIAL REGISTRATION

CRD42019124680.

Migraine and gastric disorders: Are they associated?

Background:

Migraine is a common disorder which affects quality of life. There has been an increasing interest for discovering the association of gastrointestinal (GI) disorders with migraine during past years. This study aims to evaluate the association of Helicobacter pylori contamination, gastroesophageal reflux disease (GERD), gastric ulcer (GU), and duodenal ulcer (DU) with migraine in patients who underwent upper GI endoscopy due to refractory dyspepsia.

Materials and Methods:

In this observational cross-sectional study, 341 dyspeptic patients who underwent upper GI endoscopy in Shahid Beheshti Hospital, Qom, Iran, included during 2016–2018. A checklist was used for collecting demographics, symptoms, and results from endoscopy and H. pylori testing. Diagnosis of migraine was made according to the International Headache Society criteria in patients who had headache. Data were analyzed using Chi-square and independent samples t-tests in SPSS 16 (SPSS Inc., Chicago, IL, USA) with P < 0.05 as significance level.

Results:

Among 341 patients, 141 (% 41.3) were male and 200 (58.7%) were female. 149 (43.7%) patients were diagnosed with migraine, from which 48 (32.2%) were male and 101 (67.8%) were female. The observed difference in migraine prevalence among male and female was statistically significant (P = 0.003). 198 (58.06%) patients were H. pylori contaminated, among these 138 (69.7%) suffered from migraine. Among 143 H. pylori-negative patients, there were 11 (7.7%) migraineurs. The difference in the prevalence of migraine among H. pylori positive and negative patients was significant. H. pylori and GERD were associated with migraine with P < 0.001. Patients with DU were more commonly suffering from migraine (P = 0.001). The association in patients with GU was not statistically significant (P = 0.863).

Conclusion:

Migraine might be associated with GERD, H. pylori infection, and DU, and the treatment of the underlying GI disorder may control headaches.

Migraine, dyspepsia, and Helicobacter pylori: Zeroing in on the culprit

Background: Numerous studies have evaluated the impact of Helicobacter pylori (H. pylori) eradication on the number, severity, and recurrence of migraine attacks. But the association of migraine, H. pylori, and gastrointestinal (GI) presentation is challenging. The aim of the current study was to investigate the correlation between migraine, H. pylori, and peptic ulcers among patients with dyspepsia undergoing upper GI endoscopy. Methods: 305 patients with dyspepsia referring to our endoscopy ward, Shahid Beheshti Hospital affiliated to Qom University of Medical Sciences, Qom, Iran, for upper GI endoscopy filled out the study questionnaire. If a patient was experiencing headaches and the migraine was confirmed by neurologists, he/she was asked to answer the questions related to migraine, which were prepared exactly from Migraine Disability Assessment (MIDAS) questionnaire. The relation between migraine and confirmed H. pylori contamination was investigated using statistical models. Results: Of all the 305 patients, 133 (43.6%) had confirmed episodic migraine headaches (MHs) and 177 patients (58.04%) had positive RUT for confirming H. pylori contamination, of which 123 (69.5%) had confirmed migraine. 52 (17.0%) had duodenal peptic ulcer(s), of which, 49 (94.2%) had a positive rapid urease test (RUT) (P < 0.001). 20 (6.5%) of all patients had the gastric peptic ulcer(s) which did not have a significant relation with H. pylori contamination. There was a significant relationship between the peptic ulcer site and migraine. In total, 177 patients (58.0%) had a positive RUT. History of migraine was significantly positive in those with positive H. Pylori contamination. Notably, multivariable analysis demonstrated a significant relation of H. pylori and migraine at younger ages. Conclusion: The prevalence of H. pylori and migraine in patients with dyspepsia seems to be high. Moreover, there is a meaningful association between migraine, duodenal peptic ulcers, and H. pylori infection, too.

Migraine, Cyclic Vomiting Syndrome, and Other Gastrointestinal Disorders

PURPOSE OF REVIEW

Cyclic vomiting syndrome (CVS) is a chronic functional gastrointestinal disorder characterized by episodic nausea and vomiting and is diagnosed using Rome IV criteria. CVS is being recognized more frequently in adults with a prevalence of 2%. It is associated with several functional disorders like autonomic dysfunction, anxiety, and depression, but the strongest association is with migraine. We will elucidate the close relationship between migraine and CVS and briefly discuss its association with other gastrointestinal disorders.

RECENT FINDINGS

We highlight similarities in pathophysiology, clinical presentation, and response to medications between CVS and migraine (tricyclic antidepressants, triptans, antiepileptics). We also discuss novel therapies like CGRP inhibitors which are effective in migraine and have potential for adaptation in patients with CVS. Using migraine as a template should enable investigators to elucidate the mechanisms underlying this disorder, develop novel therapies, and direct future research in CVS.

Evidence-based update on rosacea comorbidities and their common physiologic pathways

Rosacea is a common chronic inflammatory disease affecting the facial skin whose etiology and pathophysiology are the subject of much investigation. Risk factors include genetic and environmental elements that may predispose individuals to localized inflammation and abnormal neurovascular responses to stimuli. Recent studies have introduced an array of systemic rosacea comorbidities, such as inflammatory bowel disease and neurologic conditions, that can be challenging to synthesize. We critically review the current data behind reported rosacea comorbidities and identify and highlight underrecognized physiologic mediators shared among rosacea and associated comorbidities. This information may be helpful in addressing patient questions about potential systemic implications of rosacea and can serve as a candidate platform for future research to understand rosacea and improve treatments.

Clinical Implications of Associations between Headache and Gastrointestinal Disorders: A Study Using the Hallym Smart Clinical Data Warehouse

Background

The brain and gastrointestinal (GI) tract are strongly connected via neural, endocrine, and immune pathways. Previous studies suggest that headaches, especially migraines, may be associated with various GI disorders. However, upper GI endoscopy in migraineurs has shown a low prevalence of abnormal findings. Also, the majority of studies have not demonstrated an association between Helicobacter pylori (HP) infection and migraine, although a pathogenic role for HP infection in migraines has been suggested. Further knowledge concerning the relation between headaches and GI disorders is important as it may have therapeutic consequences. Thus, we sought to investigate possible associations between GI disorders and common primary headaches, such as migraines and tension-type headaches (TTH), using the Smart Clinical Data Warehouse (CDW) over a period of 10 years.

Methods

We retrospectively investigated clinical data using a clinical data analytic solution called the Smart CDW from 2006 to 2016. In patients with migraines and TTH who visited a gastroenterology center, GI disorder diagnosis, upper GI endoscopy findings, and results of HP infection were collected and compared to clinical data from controls, who had health checkups without headache. The time interval between headache diagnosis and an examination at a gastroenterology center did not exceed 1 year.

Results

Patients were age- and sex-matched and eligible cases were included in the migraine (n = 168), the TTH (n = 168), and the control group (n = 336). Among the GI disorders diagnosed by gastroenterologists, gastroesophageal reflux disorder was more prevalent in the migraine group, whereas gastric ulcers were more common in the migraine and TTH groups compared with controls (p < 0.0001). With regard to endoscopic findings, there were high numbers of erosive gastritis and chronic superficial gastritis cases in the migraine and TTH groups, respectively, and the severity of gastritis was significantly higher in patients with TTH compared with controls (p < 0.001). However, no differences were observed in the prevalence of HP infection between the groups.

Conclusion

The observed association in this study may suggest that primary headache sufferers who experience migraines or TTH are more prone to GI disorders, which may have various clinical implications. Further research concerning the etiology of the association between headaches and GI disorders is warranted.

Gastrointestinal disorders associated with migraine: A comprehensive review

Migraine is a recurrent and commonly disabling primary headache disorder that affects over 17% of women and 5%-8% of men. Migraine susceptibility is multifactorial with genetic, hormonal and environmental factors all playing an important role. The physiopathology of migraine is complex and still not fully understood. Many different neuropeptides, neurotransmitters and brain pathways have been implicated. In connection with the myriad mechanisms and pathways implicated in migraine, a variety of multisystemic comorbidities (e.g., cardiovascular, psychiatric and other neurological conditions) have been found to be closely associated with migraine. Recent reports demonstrate an increased frequency of gastrointestinal (GI) disorders in patients with migraine compared with the general population. Helicobacter pylori infection, irritable bowel syndrome, gastroparesis, hepatobiliary disorders, celiac disease and alterations in the microbiota have been linked to the occurrence of migraine. Several mechanisms involving the gut-brain axis, such as a chronic inflammatory response with inflammatory and vasoactive mediators passing to the circulatory system, intestinal microbiota modulation of the enteric immunological milieu and dysfunction of the autonomic and enteric nervous system, have been postulated to explain these associations. However, the precise mechanisms and pathways related to the gut-brain axis in migraine need to be fully elucidated. In this review, we survey the available literature linking migraine with GI disorders. We discuss the possible physiopathological mechanisms, and clinical implications as well as several future areas of interest for research.

Biodiversity, the Human Microbiome and Mental Health: Moving toward a New Clinical Ecology for the 21st Century?

Advances in research concerning the brain-related influences of the microbiome have been paradigm shifting, although at an early stage, clinical research involving beneficial microbes lends credence to the notion that the microbiome may be an important target in supporting mental health (defined here along the continuum between quality of life and the criteria for specific disorders). Through metagenomics, proteomics, metabolomics, and systems biology, a new emphasis to personalized medicine is on the horizon. Humans can now be viewed as multispecies organisms operating within an ecological theatre; it is important that clinicians increasingly see their patients in this context. Historically marginalized ecological aspects of health are destined to become an important consideration in the new frontiers of practicing medicine with the microbiome in mind. Emerging evidence indicates that macrobiodiversity in the external environment can influence mental well-being. Local biodiversity may also drive differences in human-associated microbiota; microbial diversity as a product of external biodiversity may have far-reaching effects on immune function and mood. With a focus on the microbiome as it pertains to mental health, we define environmental “grey space” and emphasize a new frontier involving bio-eco-psychological medicine. Within this concept the ecological terrain can link dysbiotic lifestyles and biodiversity on the grand scale to the local human-associated microbial ecosystems that might otherwise seem far removed from one another.

Meta-analysis of association between Helicobacter pylori infection and multiple sclerosis

Despite recent research focus on the association between Helicobacter pylori (H. pylori) infection and multiple sclerosis (MS) there is no consensus about the findings. To obtain a more comprehensive estimate of the association we conducted a meta-analysis to determine the prevalence of H. pylori infection in MS patients and healthy controls. Pubmed and EMBASE were searched to identify eligible studies. Nine studies were selected for inclusion, involving 2806 cases (1553 patients with MS and 1253 controls). Overall, the prevalence of H. pylori infection in MS patients was lower than that in control groups (24.66% vs. 31.84%, OR=0.69, 95% CI: 0.57-0.83, P<0.0001). Subgroup analysis revealed that the levels of H.pylori infection among MS patients were lower than for control subjects in Western countries (11.90% vs. 16.08%, OR=0.63, 95% CI: 0.43-0.91, P=0.01), but were not statistically significant in Eastern countries (39.39% vs. 43.82%, OR=0.79, 95% CI: 0.55-1.14, P=0.20). Our data show that H. pylori infection and MS is negatively correlated, especially in Western countries. Whether H. pylori infection is a protective factor against MS risk should thus be addressed in large-scale and prospective studies.

Extragastric Diseases and Helicobacter pylori

The extragastric manifestations of Helicobacter pylori infection still remain a very strong topic throughout the H. pylori world. Indeed, H. pylori may interfere with many biological processes, both inside and outside of the stomach, possibly influencing or determining the occurrence of many diseases outside of the stomach. While its role in idiopathic thrombocytopenic purpura and sideropenic anemia has already been recognized, emerging evidence suggests that H. pylori may increase the risk of acute coronary syndrome, contribute to insulin resistance and be associated with neurodegenerative, respiratory, and other miscellaneous disorders previously associated with other conditions. Different pathogenic mechanisms have been hypothesized, including the induction of a low-grade inflammatory state and the occurrence of molecular mimicry mechanisms. This review summarizes the results of the most relevant studies published on this topic in the last year.

Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology

For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.

Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology

For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.