Association of 5-HTT gene polymorphisms with migraine: a systematic review and meta-analysis

Serotonin Transporter (5-Hydroxytryptamine Transporter, SERT, SLC6A4) and Sodium-dependent Reuptake Inhibitors as Modulators of Pain Behaviors and Analgesic Responses

The serotonin transporter (5-hydroxytryptamine transporter [5-HTT], Serotonin Transporter (SERT), SLC6A4) modulates the activity of serotonin via sodium-dependent reuptake. Given the established importance of serotonin in the control of pain, 5-HTT has received much interest in studies of pain states and as a pharmacological target for serotonin reuptake inhibitors (SRIs). Animal models expressing varying levels of 5-HTT activity show marked differences in pain behaviors and analgesic responses, as well as many serotonin-related physiological effects. In humans, functional nucleotide variations in the SLC6A4 gene, which encodes the serotonin transporter 5-HTT, are associated with certain pathologic pain conditions and differences in responses to pharmacological therapy. These findings collectively reflect the importance of 5-HTT in the intricate physiology and management of pain, as well as the scientific and clinical challenges that need to be considered for the optimization of 5-HTT-related analgesic therapies. PERSPECTIVE: The serotonin transporter 5-HTT/SCL6A4 is sensitive to pharmacological SRIs. Experimental studies on the physiological functions of serotonin, as well as genetic mouse models and clinical phenotype/genotype correlations of nucleotide variation in the human 5-HTT/SCL6A4 gene, provide new insights for the use of SRIs in chronic pain management.

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.

Interplay between Serotonin, Immune Response, and Intestinal Dysbiosis in Inflammatory Bowel Disease

Inflammatory Bowel Disease (IBD) is a chronic gastrointestinal disorder characterized by periods of activity and remission. IBD includes Crohn's disease (CD) and ulcerative colitis (UC), and even though IBD has not been considered as a heritable disease, there are genetic variants associated with increased risk for the disease. 5-Hydroxytriptamine (5-HT), or serotonin, exerts a wide range of gastrointestinal effects under both normal and pathological conditions. Furthermore, Serotonin Transporter (SERT) coded by Solute Carrier Family 6 Member 4 (SLC6A4) gene (located in the 17q11.1-q12 chromosome), possesses genetic variants, such as Serotonin Transporter Gene Variable Number Tandem Repeat in Intron 2 (STin2-VNTR) and Serotonin-Transporter-linked promoter region (5-HTTLPR), which have an influence over the functionality of SERT in the re-uptake and bioavailability of serotonin. The intestinal microbiota is a crucial actor in normal human gut physiology, exerting effects on serotonin, SERT function, and inflammatory processes. As a consequence of abnormal serotonin signaling and SERT function under these inflammatory processes, the use of selective serotonin re-uptake inhibitors (SSRIs) has been seen to improve disease activity and extraintestinal manifestations, such as depression and anxiety. The aim of this study is to integrate scientific data linking the intestinal microbiota as a regulator of gut serotonin signaling and re-uptake, as well as its role in the pathogenesis of IBD. We performed a narrative review, including a literature search in the PubMed database of both review and original articles (no date restriction), as well as information about the SLC6A4 gene and its genetic variants obtained from the Ensembl website. Scientific evidence from in vitro, in vivo, and clinical trials regarding the use of selective serotonin reuptake inhibitors as an adjuvant therapy in patients with IBD is also discussed. A total of 194 articles were used between reviews, in vivo, in vitro studies, and clinical trials.

Biomarkers in Migraine

Background

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

Objective

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

Methods

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

Results

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

Conclusion

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

Genetic variants in migraine: a field synopsis and systematic re-analysis of meta-analyses

Objective

Numerous genetic variants from meta-analyses of observational studies and GWAS were reported to be associated with migraine susceptibility. However, due to the random errors in meta-analyses, the noteworthiness of the results showing statistically significant remains doubtful. Thus, we performed this field synopsis and re-analysis study to evaluate the noteworthiness using a Bayesian approach in hope of finding true associations.

Methods

Relevant meta-analyses from observational studies and GWAS examining correlation between all genetic variants and migraine risk were included in our study by a PubMed search. Identification of noteworthy associations were analyzed by false-positive rate probability (FPRP) and Bayesian false discovery probability (BFDP). Using noteworthy variants, GO enrichment analysis were conducted through DAVID online tool. Then, the PPI network and hub genes were performed using STRING database and CytoHubba software.

Results

As for 8 significant genetic variants from observational studies, none of which showed noteworthy at prior probability of 0.001. Out of 47 significant genetic variants in GWAS, 36 were noteworthy at prior probability of 0.000001 via FPRP or BFDP. We further found the pathways “positive regulation of cytosolic calcium ion concentration” and “inositol phosphate-mediated signaling” and hub genes including MEF2D, TSPAN2, PHACTR1, TRPM8 and PRDM16 related to migraine susceptibility.

Conclusion

Herein, we have identified several noteworthy variants for migraine susceptibility in this field synopsis. We hope these data would help identify novel genetic biomarkers and potential therapeutic target for migraine.

Associations Between Catecholaminergic and Serotonergic Genes and Persistent Arm Pain Severity Following Breast Cancer Surgery

Persistent arm pain is a common problem after breast cancer surgery. Little is known about genetic factors that contribute to this type of postsurgical pain. Study purpose was to explore associations between persistent arm pain phenotypes and genetic polymorphisms among 15 genes involved in catecholaminergic and serotonergic neurotransmission. Women (n = 398) rated the presence and intensity of arm pain monthly for 6 months after breast cancer surgery. Three distinct latent classes of patients were identified (ie, no arm pain [41.6%], mild arm pain (23.6%), and moderate arm pain (34.8%). Logistic regression analyses were used to evaluate for differences between genotype or haplotype frequencies and the persistent arm pain classes. Compared with the no arm pain class, 3 single nucleotide polymorphisms and 1 haplotype, in 4 genes, were associated with membership in the mild arm pain class: COMT rs4633, HTR2A haplotype B02 (composed of rs1923886 and rs7330636), HTR3A rs1985242, and TH rs2070762. Compared with the no arm pain class, 4 single nucleotide polymorphisms in 3 genes were associated with membership in the moderate arm pain class: COMT rs165656, HTR2A rs2770298 and rs9534511, and HTR3A rs1985242. Findings suggest that variations in catecholaminergic and serotonergic genes play a role in the development of persistent arm pain. PERSPECTIVE: Limited information is available on genetic factors that contribute to persistent arm pain after breast cancer surgery. Genetic polymorphisms in genes involved in catecholaminergic and serotonergic neurotransmission were associated with 2 persistent arm pain phenotypes. Findings may be used to identify patients are higher risk for this common pain condition.

The New *G29A and G1222A of HCRTR1, 5-HTTLPR of SLC6A4 Polymorphisms and Hypocretin-1, Serotonin Concentrations in Migraine Patients

Migraine is one of the most common primary headache disorders that affects 11% of the adult population. The disease is divided into two main clinical subtypes: migraine with aura (MA) and migraine without aura (MO). Both serotonergic and hypocretinergic systems are involved in the migraine pathomechanism. Polymorphisms in the serotonin transporter gene (SLC6A4) and the hypocretin receptor 1 gene (HCRTR1) may be risk factors for migraine development due to their ability to affect serotonin and hypocretin-1 (HCRT-1) concentrations. The aim of the study was to analyze, for the first time in the Polish population, the 5-HT transporter linked polymorphic region (5-HTTLPR) in SLC6A4, G1222A (rs2271933) and the never before studied *G29A (rs41263963) polymorphisms in the HCRTR1 gene, as well as the 5-HT and hypocretin-1 plasma concentrations in migraine patients (MA, MO) and control subjects. The study included 123 patients that were diagnosed with migraine and 123 control subjects. Methods such as PCR, HRMA and sequencing were used for genotyping, while 5-HT was determined by HPLC/EC and hypocretin-1 by ELISA. No significant differences were observed in 5-HTTLPR frequencies. The A allele of HCRTR1 G1222A occurred more often in MO, while the GA genotype of HCRTR1 *G29A was more frequent among MA when compared to control group (p < 0.05). The mean age of migraine onset in individuals with HCRTR1 *G29A was 18 years old for patients with MA and 26 years old for MO patients. The localization and type of HCRTR1 polymorphisms (G1222A-missense variant in exon 7, *G29A-3'UTR variant) may predispose patients to the clinical subtype of migraine: MO or MA, respectively. In control subjects, the short allele of 5-HTTLPR tended to decrease the 5-HT concentration, while the A allele of HCRTR1 G1222A decreased both 5-HT and hypocretin-1 levels. Serotonin concentrations differed in terms of clinical features of migraine. The relation between genotypes of 5-HTTLPR, HCRTR1 G1222A, and 5-HT concentrations may bedisturbed in migraine. It seems that HCRTR1 *G29A is more strongly associated with regulating the 5-HT in patients with MA than MO, and therefore may contribute to the early age of onset for migraine.

Genetic and biochemical changes of the serotonergic system in migraine pathobiology

Migraine is a brain disorder characterized by a piercing headache which affects one side of the head, located mainly at the temples and in the area around the eye. Migraine imparts substantial suffering to the family in addition to the sufferer, particularly as it affects three times more women than men and is most prevalent between the ages of 25 and 45, the years of child rearing. Migraine typically occurs in individuals with a genetic predisposition and is aggravated by specific environmental triggers. Attempts to study the biochemistry of migraine began as early as the 1960s and were primarily directed at serotonin metabolism after an increase of 5-hydroxyindoleacetic acid (5-HIAA), the main metabolite of serotonin was observed in urine of migraineurs. Genetic and biochemical studies have primarily focused on the neurotransmitter serotonin, considering receptor binding, transport and synthesis of serotonin and have investigated serotonergic mediators including enzymes, receptors as well as intermediary metabolites. These studies have been mainly assayed in blood, CSF and urine as the most accessible fluids. More recently PET imaging technology integrated with a metabolomics and a systems biology platform are being applied to study serotonergic biology. The general trend observed is that migraine patients have alterations of neurotransmitter metabolism detected in biological fluids with different biochemistry from controls, however the interpretation of the biological significance of these peripheral changes is unresolved. In this review we present the biology of the serotonergic system and metabolic routes for serotonin and discuss results of biochemical studies with regard to alterations in serotonin in brain, cerebrospinal fluid, saliva, platelets, plasma and urine of migraine patients.

Power-up: A Reanalysis of 'Power Failure' in Neuroscience Using Mixture Modeling

Recently, evidence for endemically low statistical power has cast neuroscience findings into doubt. If low statistical power plagues neuroscience, then this reduces confidence in the reported effects. However, if statistical power is not uniformly low, then such blanket mistrust might not be warranted. Here, we provide a different perspective on this issue, analyzing data from an influential study reporting a median power of 21% across 49 meta-analyses (Button et al., 2013). We demonstrate, using Gaussian mixture modeling, that the sample of 730 studies included in that analysis comprises several subcomponents so the use of a single summary statistic is insufficient to characterize the nature of the distribution. We find that statistical power is extremely low for studies included in meta-analyses that reported a null result and that it varies substantially across subfields of neuroscience, with particularly low power in candidate gene association studies. Therefore, whereas power in neuroscience remains a critical issue, the notion that studies are systematically underpowered is not the full story: low power is far from a universal problem.SIGNIFICANCE STATEMENT Recently, researchers across the biomedical and psychological sciences have become concerned with the reliability of results. One marker for reliability is statistical power: the probability of finding a statistically significant result given that the effect exists. Previous evidence suggests that statistical power is low across the field of neuroscience. Our results present a more comprehensive picture of statistical power in neuroscience: on average, studies are indeed underpowered-some very seriously so-but many studies show acceptable or even exemplary statistical power. We show that this heterogeneity in statistical power is common across most subfields in neuroscience. This new, more nuanced picture of statistical power in neuroscience could affect not only scientific understanding, but potentially policy and funding decisions for neuroscience research.

Molecular factors in migraine

Migraine is a common neurological disorder that affects 11% of adults worldwide. This disease most likely has a neurovascular origin. Migraine with aura (MA) and more common form - migraine without aura (MO) - are the two main clinical subtypes of disease. The exact pathomechanism of migraine is still unknown, but it is thought that both genetic and environmental factors are involved in this pathological process. The first genetic studies of migraine were focused on the rare subtype of MA: familial hemiplegic migraine (FHM). The genes analysed in familial and sporadic migraine are: MTHFR, KCNK18, HCRTR1, SLC6A4, STX1A, GRIA1 and GRIA3. It is possible that migraine is a multifactorial disease with polygenic influence.Recent studies have shown that the pathomechanisms of migraine involves both factors responsible for immune response and oxidative stress such as: cytokines, tyrosine metabolism, homocysteine; and factors associated with pain transmission and emotions e.g.: serotonin, hypocretin-1, calcitonin gene-related peptide, glutamate. The correlations between genetic variants of the HCRTR1 gene, the polymorphism 5-HTTLPR and hypocretin-1, and serotonin were observed. It is known that serotonin inhibits the activity of hypocretin neurons and may affect the appearance of the aura during migraine attack.The understanding of the molecular mechanisms of migraine, including genotype-phenotype correlations, may contribute to finding markers important for the diagnosis and treatment of this disease.

Childhood Maltreatment in the Migraine Patient

OPINION STATEMENT

Maltreatment during childhood increases vulnerability to a host of health disorders, including migraine. Putative mechanisms linking maltreatment and migraine include stress-induced dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, as well as disruption of other stress-mediating homeostatic systems, including those involving endocannabinoids, monoamine neurotransmitters, oxytocin, and inflammation. Prolonged elevation of glucocorticoids alters the neural architecture of the limbic system, resulting in the structural as well as functional changes described in both maltreatment and in migraine. Although treatment trials for migraine have not stratified participants by abuse history, strategies, such as cognitive behavioral therapy, which alter stress responsivity, may be particularly effective in this subgroup. Some therapies involving the endocannabinoid, serotonergic, oxytonergic, and inflammatory systems are under investigation for migraine. Anti-epileptic drugs such as valproate and topiramate, which are FDA approved for migraine treatment, are also known to interfere with epigenetic changes induced by stress. Discerning the role for this mechanism in treatment of maltreated migraineurs may introduce another therapeutic avenue.

Association of serotonin transporter gene (5HTT) polymorphism and juvenile myoclonic epilepsy: a case-control study

Serotonin levels might alter susceptibility to seizures. Serotonin transporter (5HTT) gene polymorphisms were found to be associated with some forms of epilepsy. Here, we attempted to examine an association between 5HTT VNTR allele variants in a serotonin transporter gene and epileptogenesis in juvenile myoclonic epilepsy (JME) cases. We conducted a case-control candidate gene study evaluating the frequencies of 5HTT VNTR allele variants using SYBR green real-time PCR with melting curve analysis in JME patients and healthy subjects. Forty patients with JME were selected from the Epilepsy Outpatient Clinic of Kasr Al Ainy Hospital, Cairo University, who had been classified according to the electroclinical classification of the ILAE. The control group consisted of 40 healthy Egyptian subjects. The less efficient transcriptional genotypes for 5-HTT polymorphisms were more frequent in JME patients (OR 9.33, CI 2.85-30.60; p value < 0.001). In our study we detected an association between the presence of 5-HTTVNTR with less transcriptional efficient genotypes and JME, which suggests that modulation of the serotoninergic system might be indicated in epileptogenesis in JME.

Serotonin, 5HT1 agonists, and migraine: new data, but old questions still not answered

PURPOSE OF REVIEW

The serotonergic system has long been linked to migraine but recent studies highlight how much is still unclear about this link. And recent data add to the uncertainty of where/how triptans act and why they are headache specific.

RECENT FINDINGS

Markers of 5HT levels in the brains of migraine patients show no changes between attacks. Several recent meta-analyses show the most convincing data on genetic differences in the serotonergic system for 5HT transporters. Findings of additional triptan actions on peripheral trigeminovascular neurons and in the hypothalamus add more fuel to the debate on where these drugs act. A growing list of studies show efficacy of multiple triptans and other 5HT1b/1d agonists in preclinical models of nonheadache pain arguing for reevaluation of whether these drugs have efficacy in other pain states. Despite these issues, serotonergic drugs continue to be the gold standard for abortive agents with new members on the horizon (5HT1f agonists).

SUMMARY

Given the clear efficacy of serotonergic drugs for migraine, continued study on the role of the endogenous 5HT system may lead to more novel therapies. And with the list of studies demonstrating efficacy triptans in models of nonheadache, clinical studies should address whether these drugs work for other types of pain.

Decreased mean platelet volume in panic disorder

AIM

The relationship between psychological stress and platelet activation has been widely studied. It is well known that platelets may reflect certain biochemical changes that occur in the brain when different mental conditions occur. Platelet 5-hydroxytryptamine (5-HT) is also extensively studied in psychiatry. The mean platelet volume (MPV), the accurate measure of platelet size, has been considered a marker and determinant of platelet function. The aim of the present study was to search for any probable difference in the MPV of subjects with panic disorder (PD).

METHODS

A total of 37 drug-free subjects, aged 18 to 65 years, diagnosed with PD, with or without agoraphobia, according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth edition (DSM-IV) criteria and 45 healthy control subjects were included in the study. Platelet count and MPV were measured and recorded for each subject.

RESULTS

There were no statistically significant differences between groups in terms of female/male ratio, age, or body mass index between the PD group and control group (P=0.91, P=0.82, and P=0.93, respectively). The MPV was found to be significantly lower in the PD group compared with the control group (8.8±0.9 fL vs 9.2±0.8 fL; P=0.02). All the participants had MPV values in the standard range of 6.9-10.8 fL.

CONCLUSION

We concluded that abnormalities of the 5-HT1A receptor function in the central nervous system of subjects with a diagnosis of PD are also mirrored in as an alteration in platelet activity. Measurements of platelet activity may be used as a tool for neuropsychiatric and psychopharmacological research and for studying how certain mental diseases and medications affect the central nervous system.

Studies on the pathophysiology and genetic basis of migraine

Migraine is a neurological disorder that affects the central nervous system causing painful attacks of headache. A genetic vulnerability and exposure to environmental triggers can influence the migraine phenotype. Migraine interferes in many facets of people's daily life including employment commitments and their ability to look after their families resulting in a reduced quality of life. Identification of the biological processes that underlie this relatively common affliction has been difficult because migraine does not have any clearly identifiable pathology or structural lesion detectable by current medical technology. Theories to explain the symptoms of migraine have focused on the physiological mechanisms involved in the various phases of headache and include the vascular and neurogenic theories. In relation to migraine pathophysiology the trigeminovascular system and cortical spreading depression have also been implicated with supporting evidence from imaging studies and animal models. The objective of current research is to better understand the pathways and mechanisms involved in causing pain and headache to be able to target interventions. The genetic component of migraine has been teased apart using linkage studies and both candidate gene and genome-wide association studies, in family and case-control cohorts. Genomic regions that increase individual risk to migraine have been identified in neurological, vascular and hormonal pathways. This review discusses knowledge of the pathophysiology and genetic basis of migraine with the latest scientific evidence from genetic studies.

Associations between serotonin transporter gene polymorphisms and heat pain perception in adults with chronic pain

BACKGROUND

The triallelic serotonin transporter gene linked polymorphic region (5-HTTLPR) has been associated with alterations in thermal pain perception. The primary aim of this study was to investigate the associations between heat pain (HP) perception and the triallelic 5-HTTLPR in a large cohort of adults with chronic pain.

METHODS

The cohort included 277 adults with chronic pain who met inclusion criteria, and were consecutively admitted to an outpatient pain rehabilitation program from March 2009 through March 2010. Individuals were genotyped for the triallelic 5-HTTLPR (including rs25531) and categorized as high, intermediate, or low expressors of the serotonin transporter. Standardized measures of HP perception were obtained using a validated quantitative sensory test method of levels.

RESULTS

The distribution of the high, intermediate, and low expressing genotypes was 61 (22%), 149 (54%) and 67 (24%), respectively. The Hardy-Weinberg P-value was 0.204 which indicated no departure from equilibrium. A significant effect of genotype was observed for values of HP threshold (P = 0.029). Individual group comparisons showed that values of HP threshold were significantly greater in the intermediate compared to the high expressing group (P = 0.009) but not the low expressing group (P > 0.1). In a multiple variable linear regression model, the intermediate group (P = 0.034) and male sex (P = 0.021) were associated with significantly greater values of HP 0.5, but no significant genotype-by-sex interaction effect was observed.

CONCLUSIONS

In this study that involved adults with chronic pain, the intermediate triallelic 5-HTTLPR expressing group, but not the low expressing group, was associated with greater HP thresholds compared to the high expressing group.

Power failure: why small sample size undermines the reliability of neuroscience

A study with low statistical power has a reduced chance of detecting a true effect, but it is less well appreciated that low power also reduces the likelihood that a statistically significant result reflects a true effect. Here, we show that the average statistical power of studies in the neurosciences is very low. The consequences of this include overestimates of effect size and low reproducibility of results. There are also ethical dimensions to this problem, as unreliable research is inefficient and wasteful. Improving reproducibility in neuroscience is a key priority and requires attention to well-established but often ignored methodological principles.

Emerging genomic biomarkers in migraine

Migraine is a debilitating neurovascular condition classified as either migraine with aura or migraine without aura. A significant genetic basis has been implicated in migraine and has probed the role of neurotransmitters, hormones and vascular genes in this disorder. The aim of this review is to highlight the recent genetic discoveries contributing to our understanding of the complex pathogenesis of migraine. The current review will discuss the role of neurotransmitter-related genes in migraine, including the recently identified TRESK and variants of the KCNN3 gene, as well as outlining studies investigating hormone receptor genes, such as ESR1 and PGR, and vascular-related genes, including the MTHFR and NOTCH 3 genes.

Attachment styles in children affected by migraine without aura

BACKGROUND

In recent years, great attention has been given to the presence of psychological problems and psychiatric comorbidity that are also present in children affected by primary headaches. The relationship between pain and attachment has been identified, and it may be that pain perception may change in relation with specific attachment styles. The aim of the present study was to assess the prevalent attachment style and verify its putative relationship and correlation with the main characteristics of migraine attacks, in school-aged children affected by migraine without aura (MoA).

MATERIALS AND METHODS

The study population consisted of 219 children (103 males, 116 females) aged between 6 and 11 years (mean 8.96 ± 2.14 years), consecutively referred for MoA compared with 381 healthy controls (174 males, 207 females; mean age 9.01 ± 1.75 years) randomly selected from schools. All the children were classified according to the attachment typologies of the Italian modified version of the Separation Anxiety Test; monthly headache frequency and mean headache duration were assessed from daily headache diaries kept by all the children. Headache intensity was assessed on a visual analog scale. The chi-square test and t-test, where appropriate, were applied, and the Spearman rank correlation test was applied to explore the relationship between the types of attachment style and clinical aspects of MoA.

RESULTS

The MoA group showed a significantly higher prevalence of type A (avoidant) attachment (P<0.001) and a significantly lower prevalence of type B (secure) attachment (P<0.001) compared with the control group. Moreover, the Spearman rank correlation analysis showed a significant relationship between MoA characteristics and the attachment style of MoA children.

CONCLUSION

The main findings of the present study were the higher prevalence among MoA children of the avoidant attachment style (type A) and the significantly lower prevalence of the secure style attachment (type B) compared with the normal controls, suggesting that the study of psychiatric comorbidity in pediatric headache may be enriched by this new aspect of analysis.

Association of 231G>A polymorphism of endothelin type A receptor gene with migraine: a meta-analysis

BACKGROUND/AIMS

Vascular dysfunction is implied in migraine. Endothelin type A receptor (EDNRA) is a receptor for endothelin-1, a potent vasoconstrictor. Several studies have investigated the association between EDNRA -231G>A SNP and migraine, but showed conflicting results. This study aimed to evaluate the association between EDNRA -231A allele and migraine by meta-analysis.

METHODS

Relevant databases were searched to identify eligible studies published in English from 2000 to 2012. Data were extracted using standardized forms. The association was assessed by relative risk (RR) with 95% confidence intervals (CIs) using a fixed or random effects model to determine the strength of the genetic association.

RESULTS

Three studies comprising 440 migraineurs, 222 subjects with tension-type headaches (TTHs) and 1323 controls were included in the meta-analysis. A significant difference was found between migraineurs and controls with AA genotype vs. AG+GG, and pooled RR with fixed effect was 4.04 (95% CI 1.173, 1.585; p=0.000, I(2)=15.1%). However, there was no statistically significant difference between TTH and controls (p=0.774).

CONCLUSIONS

This meta-analysis provides evidence suggesting a significant association between EDNRA -231G>A polymorphism and migraine.

Nutraceutical preparations in childhood migraine prophylaxis: effects on headache outcomes including disability and behaviour

Migraine is common in children, but few specific drugs are available. We performed an open-label comparison of effects of two nutraceutical preparations (ginkgolide B vs. Griffonia simplicifolia extract) on outcomes in 374 school-age children (mean 10.7 years) with migraine without aura. Half of them received ginkgolide B; and half, Griffonia simplicifolia. Both preparations were given orally twice a day for 6 months. Patients kept a headache diary. Outcomes at the beginning and end of treatment were compared. Both preparations reduced all outcome measures after 6 months of treatment. However, reductions in headache frequency, duration and intensity, PedMIDAS score and behavioural reactions to headache were significantly greater in the ginkgolide B group. Both nutraceutical treatments appear promising in paediatric migraine without aura, particularly because of their lack of side effects. However, the ginkgolide B preparation was significantly more effective in the medium-term (6 months).

Negative affectivity moderated by BDNF and stress response

BACKGROUND

Gene×environment (G×E) interactions are known to predict susceptibility to disorders such as depression and anxiety. Adverse experiences in childhood and number of stressful life events (SLEs) have been widely studied as environmental risk factors; however, SLE response has not yet been studied. Here we present a first attempt at the analysis of the interaction between the response to personal and academic stressful events during different life stages and the gene polymorphisms 5-HTTLPR, 5-HTTVNTR (STin2), HTR1A C(-1019)G, and BDNF Val66Met in the prediction of negative affectivity (NA).

METHODS

Standardized questionnaires (ST-DEP and STAI) were used to measure negative affectivity derived from depression and anxiety in a sample of 303 undergraduate students. Response to stressful events during childhood, high school and college years was evaluated together with a self-report personal history form. Multiple logistic regression analysis was used to perform association and G×E analysis.

RESULTS

Negative affectivity is strongly associated with childhood maltreatment and stress response. Gene associations were observed between 5-HTTVNTR allele 12 and the S_12 haplotype with NA derived from high scores in both depression and anxiety. The BDNF gene variant was not associated with NA derived from depression or anxiety alone, but it was associated with the comorbid presentation. A significant G×E interaction was observed between the BDNF Val66Met and stress response during childhood and college years although the risk for negative affectivity conferred by stress response during childhood was only significant among the Met allele carriers, while stress response during college years was a significant risk factor regardless of the BDNF Val66Met genotype. A significant G×E interaction was also found between the HTR1A C(-1019)G variant and childhood maltreatment.

LIMITATIONS

The study has two main limitations, sample size is low and retrospective recognition of SLEs is a concern.

CONCLUSION

Altogether, our results demonstrate that the BDNF Val66Met variant moderates the effect of stress during both childhood and college years; although this effect seems to be more critical during childhood given that the risk conferred by childhood stress was restricted to the Met allele carriers. We also found that the HTR1A C(-1019)G variant moderates the effect of childhood maltreatment in our study population.