Biomarkers in Migraine

Biomarkers in headaches as a potential solution to simplify differential diagnosis of primary headache disorders: a systematic review

BACKGROUND

According to the International Classification of Headache Disorders, 3rd edition (ICHD-3), headache disorders can be divided into two main groups: primary, which are not caused by any other disease, and secondary, which are symptomatic of underlying disease. Differentiating between both groups is crucial for the patient's prognosis. The diagnosis of primary headache disorders relies solely on official clinical criteria, with no additional diagnostic tools available. Therefore, they usually remain underdiagnosed, decreasing the patient's quality of life.

METHODS

This systematic review aimed to analyse the available literature on the topic of biomarkers in the differentiation between different types of headaches. To be included, a primary study had to cover the abovementioned topic. Studies comparing one type of headache to healthy controls were excluded since the review focused on differential diagnosis. Articles to be considered had to describe original research and be written in English or Polish. No publication year limits were applied. A selection process was performed between October 19th, 2024, and January 1st, 2025, through six databases (PubMed, Embase, Scopus, Cochrane, Web of Science, Medline Ultimate), according to the PRISMA 2020. The risk of bias was assessed accordingly using the Prediction Model Risk of Bias Assessment Tool (PROBAST), and data synthesis was performed narratively. The review was registered in PROSPERO.

FINDINGS

The findings from 21 included studies (with a wide range of publication years between 1990 and 2023) demonstrated several biomarkers, mainly comparing migraine to other primary headaches, tension-type headaches and cluster headaches, and some secondary headaches: medication-overuse headaches and post-traumatic headaches. The main types of biomarkers were blood biomarkers and imaging biomarkers. Among the former, molecules such as magnesium and calcitonin gene-related peptide (CGRP) or inflammatory markers could be found. The latter group focused mainly on assessing volumes or functional connections in brain magnetic resonance imaging and seem to have a significant impact in the nearest future. Saliva analyses were covered only by two research groups, showing the putative role of magnesium and CGRP. Similarly, two research groups described evoked potentials' value only in the paediatric population.

CONCLUSIONS

There is a clear gap in the literature regarding biomarkers for the differential diagnosis of headaches. However, an analysis of the most recent studies suggests that imaging biomarkers are the most promising group since they have gained the most attention in the past few years. Finding high-value biomarkers can simplify differential diagnosis of headaches, especially when clinical presentation is atypical. Nevertheless, more research on biomarkers of all types is highly needed.

PROSPERO

Registration ID: CRD42024603632.

Oxidative Stress and Migraine

The pathogenesis of migraine is not completely understood, but inflammation and oxidative stress seem to be involved, according to data from an experimental model of the disease. This narrative review summarizes data from studies on oxidative stress markers in migraine patients, case-control association studies on the possible association of candidate genes related to oxidative stress with the risk for migraine, studies showing the presence of oxidative stress in experimental models of migraine, and studies on the efficacy of antioxidant drugs in migraine therapy. Many studies have addressed the value of concentrations of prooxidant and antioxidant substances or the activity of antioxidant enzymes in different tissues (mainly in serum/plasma or in blood cells) as possible biomarkers for migraine, being thiobarbituric acid (TBA) reactive substances (TBARS) such as malonyl dialdehyde acid (MDA) and 4-hydroxynonenal, and nitric oxide (this at least during migraine attacks in patients with migraine with aura (MWA) the most reliable. In addition, the possible usefulness of antioxidant treatment is not well established, although preliminary short-term studies suggest a beneficial action of some of them such as Coenzyme Q10 and riboflavin. Both topics require further prospective, multicenter studies with a long-term follow-up period involving a large number of migraine patients and controls.

[A comparative assessment of microbiocenosis of saliva and oropharynx in patients with migraine]

OBJECTIVE

To identify changes in the microbiome of saliva and to compare it with the microbiome of the oropharynx of patients with migraine.

MATERIAL AND METHODS

Sixty patients with migraine (21-56 years old), were examined using a headache diary, MIDAS and VAS. A microbiological examination of saliva and smear from the mucosa of the posterior wall of the oropharynx with evaluation by the method of mass spectrometry of microbial markers (MSMM) with the determination of 57 microorganisms was performed. All patients had comorbid chronic diseases of the gastrointestinal tract and upper respiratory tract (URT), according to anamnestic data and examination by specialists.

RESULTS

A significant increase in the content of markers of resident (conditionally pathogenic) microorganisms characteristic of chronic diseases of URT (strepto- and staphylococci); markers of transient microorganisms characteristic of intestinal microflora (clostridia, gram-negative rods, anaerobes) that are normally absent; viral markers of cytomegaloviruses and herpes groups; a decrease in the content of fungi were identified in saliva. A comparative analysis of the microbiome of saliva and oropharynx showed: 1) a significant decrease in the concentration of coccal flora Enterococcus spp., Streptococcus mutans, Staphylococcus aureus, anaerobic bacteria Clostridium difficile and Clostridium perfringens in saliva; enterobacteria Helicobacter pylori; gram-negative rods Kingella spp., fungi and Epstein-Barr virus; 2) an increase in salivary concentrations of Staphylococcus epidermidis, anaerobic Clostridium ramosum and Fusobacterium spp./Haemophilus spp. and gram-negative bacilli Porphyromonas spp.

CONCLUSION

A comparative assessment of the microbiota of a smear from the posterior wall of the oropharynx and saliva using MMSM showed the presence of dysbiosis both in the oropharynx and in the saliva of patients with migraine. However, there were fewer deviations from the norm in saliva, therefore, for diagnostic purposes, a smear from the posterior wall of the oropharynx is more significant as a biomarker for patients with migraine.

Plasma calcitonin gene-related peptide and nerve growth factor as headache and pain biomarkers in recently deployed soldiers with and without a recent concussion

OBJECTIVE

The objective of this study was to characterize the utility of calcitonin gene-related peptide (CGRP) and nerve growth factor (NGF) as potential biomarkers for headache and pain disorders in the post-military deployment setting.

BACKGROUND

The need to improve recognition, assessment, and prognoses of individuals with posttraumatic headache or other pain has increased interest in the potential of CGRP and NGF as biomarkers.

METHODS

The Warrior Strong Study (NCT01847040) is an observational longitudinal study of United States-based soldiers who had recently returned from deployment to Afghanistan or Iraq from 2009 to 2014. The present nested cross-sectional analysis uses baseline data collected from soldiers returning to Fort Bragg, North Carolina.

RESULTS

In total, 264 soldiers (mean (standard deviation [SD] age 28.1 [6.4] years, 230/264 [87.1%] men, 171/263 [65.0%] White) were analyzed. Mean (SD) plasma levels of CGRP were 1.3 (1.1) pg/mL and mean levels of NGF were 1.4 (0.4) pg/mL. Age was negatively correlated with NGF (-0.01 pg/mL per year, p = 0.007) but was not associated with CGRP. Men had higher mean (SD) CGRP plasma levels than women (1.4 95% confidence interval [CI; 1.2] vs. 0.9 95% CI [0.5] pg/mL, p < 0.002, Kruskal-Wallis test). CGRP levels were lower in participants who had a headache at the time of the blood draw (1.0 [0.6] pg/mL vs. 1.4 [1.2] pg/mL, p = 0.024). NGF was lower in participants with continuous pain (all types; 1.2 [0.4] vs. 1.4 [0.4] pg/mL, p = 0.027) and was lower in participants with traumatic brain injury (TBI) + posttraumatic headache (PTH) versus TBI without PTH (1.3 [0.3] vs. 1.4 [0.4] pg/mL, p = 0.021). Otherwise, CGRP and NGF were not associated with migraine-like headache, TBI status, or headache burden as measured by the number of medical encounters in crude or adjusted models.

CONCLUSION

In this exploratory study, plasma levels of NGF and CGRP showed promise as biomarkers for headache and other types of pain. These findings need to be replicated in other cohorts.

Biomarkers of Migraine: An Integrated Evaluation of Preclinical and Clinical Findings

In recent years, numerous efforts have been made to identify reliable biomarkers useful in migraine diagnosis and progression or associated with the response to a specific treatment. The purpose of this review is to summarize the alleged diagnostic and therapeutic migraine biomarkers found in biofluids and to discuss their role in the pathogenesis of the disease. We included the most informative data from clinical or preclinical studies, with a particular emphasis on calcitonin gene-related peptide (CGRP), cytokines, endocannabinoids, and other biomolecules, the majority of which are related to the inflammatory aspects and mechanisms of migraine, as well as other actors that play a role in the disease. The potential issues affecting biomarker analysis are also discussed, such as how to deal with bias and confounding data. CGRP and other biological factors associated with the trigeminovascular system may offer intriguing and novel precision medicine opportunities, although the biological stability of the samples used, as well as the effects of the confounding role of age, gender, diet, and metabolic factors should be considered.

Lack of Association between Common LAG3/CD4 Variants and Risk of Migraine

Several papers have been published suggesting a probable role of inflammatory factors in the etiopathogenesis of migraine. In this study, we investigated the possible association between common variants in the LAG3/CD4 genes (both genes, which are closely related, encode proteins involved in inflammatory and autoimmune responses) in the risk of migraine in a cohort of Caucasian Spanish participants. For this purpose, the frequencies of CD4 rs1922452, CD4 rs951818, and LAG3 rs870849 genotypes and allelic variants, using a specific TaqMan-based qPCR assay, were assessed in 290 patients diagnosed with migraine and in 300 healthy controls. The relationship of these variables with several clinical features of migraine was also analyzed. The frequencies of the analyzed LAG3/CD4 genotypes did not differ significantly between the two study groups and were not related to the sex, age at onset of migraine, family history of migraine, presence or absence of aura, or the triggering effect of ethanol on migraine episodes. These results suggest a lack of association between common variants in the LAG3/CD4 genes and the risk of developing migraine in the Caucasian Spanish population.

Distribution of PACAP and PAC1 Receptor in the Human Eye

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide with widespread distribution and diverse biological functions. Several studies show that PACAP has strong cytoprotective effects mediated mostly through its specific PAC1 receptor (PAC1-R) and it plays important roles in several pathological conditions. Its distribution and altered expression are known in various human tissues, but there is no descriptive data about PACAP and its receptors in the human eyebulb. Since PACAP38 is the dominant form of the naturally occurring PACAP, our aim was to investigate the distribution of PACAP38-like immunoreactivity in the human eye and to describe the presence of PAC1-R. Semiquantitative evaluation was performed after routine histology and immunohistochemical labeling on human eye sections. Our results showed high level of immunopositivity in the corneal epithelium and endothelium. Within the vascular layer, the iris and the ciliary body had strong immunopositivity for both PACAP and PAC1-R. Several layers of the retina showed immunoreactivity for PACAP and PAC1-R, but the ganglion cell layer had a special pattern in the immunolabeling. Labeling was observed in the neuropil within the optic nerve in both cases and glial cells displayed immunoreactivity for PAC1-R. In summary, our study indicates the widespread occurrence of PACAP and its specific receptor in the human eye, implying that the results from in vitro and animal studies have translational value and most probably are also present in the human eye.