[Pathophysiology of Headaches]

Effectiveness of intraoral splints in the treatment of migraine and tension-type headache: A systematic review

OBJECTIVES

The main objective of this systematic review was to assess the effectiveness of intraoral splints in treating migraine and tension-type headaches.

MATERIAL AND METHODS

The article search was conducted within seven electronic databases (Medline, PubMed, Embase, CINAHL PLUS with full text, Cochrane Library Trials, Web of Science, and Scopus) with no date limits or language restrictions up to June 12, 2022. Strict inclusion and exclusion criteria were set for article selection. At the same time as data extraction, each study's risk of bias (RoB) was evaluated using the Cochrane tool to assess their RoB. Subsequently, the Cochrane Grading of Recommendations Assessment Development and Evaluation was used to evaluate the certainty of the evidence.

RESULTS

Four controlled clinical trials were included. These trials were heterogeneous in terms of (1) diagnosis, (2) design of the intraoral splints, and (3) tools for reporting the results, which made it difficult to compile the data as well as evaluate its quality. Trials reported a reduction in the frequency of headache and pain intensity when using intraoral splints; however, this therapy was not superior to medications.

CONCLUSIONS

The evidence is very low for the use of oral splints as a therapeutic alternative to medication in the treatment of migraine and/or tension-type headache.

Roxadustat alleviates nitroglycerin-induced migraine in mice by regulating HIF-1α/NF-κB/inflammation pathway

Sensitization of central pain and inflammatory pathways play essential roles in migraine, a primary neurobiological headache disorder. Since hypoxia-inducible factor-1α (HIF-1α) is implicated in neuroprotection and inflammation inhibition, herein we investigated the role of HIF-1α in migraine. A chronic migraine model was established in mice by repeated injection of nitroglycerin (10 mg/kg, i.p.) every other day for 5 total injections. In the prevention and acute experiments, roxadustat, a HIF-1α stabilizer, was orally administered starting before or after nitroglycerin injection, respectively. Pressure application measurement, and tail flick and light-aversive behaviour tests were performed to determine the pressure pain threshold, thermal nociceptive sensitivity and migraine-related light sensitivity. At the end of experiments, mouse serum samples and brain tissues were collected for analyses. We showed that roxadustat administration significantly attenuated nitroglycerin-induced basal hypersensitivity and acute hyperalgesia by improving central sensitization. Roxadustat administration also decreased inflammatory cytokine levels in serum and trigeminal nucleus caudalis (TNC) through NF-κB pathway. Consistent with the in vivo results showing that roxadustat inhibited microglia activation, roxadustat (2, 10, and 20 μM) dose-dependently reduced ROS generation and inflammation in LPS-stimulated BV-2 cells, a mouse microglia cell line, by inhibiting HIF-1α/NF-κB pathway. Taken together, this study demonstrates that roxadustat administration ameliorates migraine-like behaviours and inhibits central pain sensitization in nitroglycerin-injected mice, which is mainly mediated by HIF-1α/NF-κB/inflammation pathway, suggesting the potential of HIF-1α activators as therapeutics for migraine.

Severity and Its Contributing Factors in Patients With Vestibular Migraine: A Cohort Study

Objective: As a recently defined disease entity, vestibular migraine (VM) is a variant of migraine with broad spectrum of manifestations. We evaluated a prospective cohort of patients with VM in two centers to assess severity of VM attacks and investigate its contributing factors in patients with VM. Methods: Adult participants with the diagnosis of VM or probable VM were enrolled according to the 2012 International Headache Society-Bárány Society Criteria. Every outpatient was followed up for 6 months to record the occurrence of VM attacks. Clinical data such as age, sex, number of VM attacks, severity on the visual analog scale, and lipid intake were collected and analyzed. Generalized Anxiety Disorder-7, Patient Health Questionnaire-9, Horne and Ostberg Morningness-Eveningness Questionnaires, and Pittsburgh Sleep Quality Index were also administered to find contributing factors. Results: During a 6-month clinical follow-up, 313 VM attack were reported. According to the Visual Analog Scale, the patients were divided into two groups. Then univariate and multivariable analyses were conducted. Among the risk factors, duration of illness (adjusted OR, 1.041; 95% CI, 1.010-1.073; P = 0.009), time of onset: 00:00:00-12:00:00 (adjusted OR, 3.961; 95% CI, 1.966-7.979; P < 0.001) and PSQI scores (adjusted OR, 1.086; 95% CI, 1.002-1.178; P = 0.046) were significantly associated with the severity of VM attack assessed by VAS. Conclusion: The data suggest that patients tended to experienced more severe VM attacks in early hours of a day, especially for those sufferers with longer duration of illness or poor sleep quality. Targeted management of such factors is required to reduce the severity of attacks.

An Investigation of the Prevalence of Subclinical Brain Lesions in MRI Images of Migraine Patients

BACKGROUND

The use of the MRI method has opened up a new perspective on pathogenesis, diagnosis and treatment of brain lesions.

AIM

Therefore, this study aimed to evaluate the prevalence of brain subclinical lesions in MRI images of migraine patients.

METHODS

This cross-sectional study was conducted on 300 patients with a migraine referred to Baqiyatallah and Amir Al-Momenin Hospitals from 2005 to 2006. We measured the relationship between the results of MRI and the type of brain subclinical lesion by indices such as age, gender, type of a migraine, the number of migraine attacks, blood pressure and heart diseases, cholesterol, diabetes and thyroid diseases. Finally, data were analysed by IBM SPSS statistics software version 23. The significance level in this study was considered as P > 0.05.

RESULTS

From among 300 patients, 87.7% were women in the age range of 13-72 years. Moreover, the results indicated that with increasing age, blood pressure and some migraine attacks, the frequency of abnormal MRI also is increased significantly as well as the ratio of a migraine with aura was significantly higher than a migraine without aura in individuals with abnormal MRI. Also, the ratio of white matter lesions (WML) is higher in a classical migraine (a Migraine with aura). Statistical analyses did not reveal any significant relationship between MRI results on age, diabetes, cholesterol, heart and thyroid diseases.

CONCLUSION

The prevalence of abnormal MRI in older people and those with high blood pressure and migraine with aura is higher, and the ratio of subclinical lesions in the population of a migraine with aura is more common than a migraine without aura.