Leukocyte inflammatory phenotype and function in migraine patients compared with matched non-migraine volunteers: a pilot study

Revisiting Migraine Pathophysiology: from Neurons To Immune Cells Through Lens of Immune Regulatory Pathways

Migraine is a prevalent neurological disorder characterized by severe, recurrent headaches accompanied by symptoms, such as nausea, photophobia, and phonophobia, significantly affecting the quality of life of millions of people worldwide. Although the neurovascular pathway, involving blood vessel dilation and neurogenic inflammation, has been a cornerstone in understanding migraine pathophysiology. Emerging evidence suggests that immune dysregulation plays a pivotal role in the onset and progression of migraine. This review uniquely synthesizes recent advances linking immune regulatory pathways to migraine, an area that has not been widely explored in the literature. Specifically, we highlighted the involvement of CD4 + CD25 + regulatory T (Treg) cells, interleukins, and pro-inflammatory and anti-inflammatory cytokines, which have been implicated in pain signaling and immune imbalance in patients with migraine. Furthermore, genetic studies have provided compelling evidence by identifying associations between migraine susceptibility and immune-related polymorphisms, particularly in forkhead box P3 (FOXP3) and nuclear factor of activated T cells (NFAT). Moreover, the higher prevalence of migraine in individuals with comorbid autoimmune diseases further supports the hypothesis of a shared pathophysiological mechanism. Despite the growing recognition of immune involvement in migraine, its precise mechanisms remain unclear. By integrating key immune biomarkers and genetic insights, this review proposes a novel framework for understanding the immune-mediated pathways in migraine progression. Future research should focus on elucidating the specific immunological mechanisms underlying migraine, which could open new avenues for innovative, targeted therapeutic strategies.

A study of changes in hematologic parameters in patients with migraine

INTRODUCTION

To evaluate the characteristics of hematological parameters and peripheral inflammatory markers (PIMs) in migraine, including chronic migraine (CM) and episodic migraine (EM), and to explore their underlying mechanisms.

METHOD

A total of 88 subjects were enrolled, 58 with migraine (28 with CM and 30 with EM) and 30 healthy controls. All subjects were matched for age, gender, and body mass index, and peripheral blood was collected. Hematological parameters and PIMs were compared between migraineurs and healthy controls. The patients underwent hematological laboratory testing and calculated the PIMs. PIMs included neutrophil/lymphocyte ratio, lymphocyte/monocyte ratio (LMR), neutrophil/monocyte ratio, platelet/lymphocyte ratio, and platelet/monocyte ratio (PMR) ratio.

RESULT

Monocyte counts in migraine patients were significantly lower compared with healthy controls, while LMR and PMR were significantly higher. Statistically significant differences were observed in monocyte counts, LMR, and PMR among the three groups of CM, EM, and HC patients. Post hoc Bonferroni t-test showed that monocyte counts were significantly lower in the EM group compared with the HC group, while LMR and PMR were significantly higher. Comparison between the EM and CM groups showed that LMR was significantly higher in the EM group. Differences in monocyte counts, LMR, and PMR between the CM and HC groups were not statistically significant. Receiver operating characteristic curve analysis indicated that the area under the curve (AUC) for the diagnosing migraine using the combination of Mon, LMR, and PMR was 0.707, and the AUC for the diagnosis of EM was 0.758. The AUC value of PMR for diagnosing CM was 0.669, while the AUC for the combination of LMR and platelet/lymphocyte ratio in distinguishing CM and EM was 0.705.

CONCLUSION

Our findings indicate that migraine and its subtypes exhibit abnormalities in monocyte counts and PIMs, which possess diagnostic predictive value for differentiating migraine and its subtypes. This suggests that systemic inflammation may play a role in the pathogenesis of migraine.

Neuroimmune interactions in the development and chronification of migraine headache

Migraine is highly prevalent and debilitating. The persistent headaches in this condition are thought to arise from the activation and sensitization of the trigeminovascular pathway. Both clinical and animal model studies have suggested that neuroimmune interactions contribute to the pathophysiology of migraine headache. In this review, we first summarize the findings from human studies implicating the dysregulation of the immune system in migraine, including genetic analyses, measurement of circulatory factors, and neuroimaging data. We next discuss recent advances from rodent studies aimed at elucidating the neuroimmune interactions that manifest at various levels of the trigeminovascular pathway and lead to the recruitment of innate and adaptive immune cells as well as immunocompetent glial cells. These cells reciprocally modulate neuronal activity via multiple pro- and anti-inflammatory mediators, thereby regulating peripheral and central sensitization. Throughout the discussions, we highlight the potential clinical and translational implications of the findings.

Fundamentals of Nonparametric Statistical Tests for Dental Clinical Research

This article provides the foundation for employing nonparametric testing in dental clinical research. To make wise judgments in their research, investigators should learn more about the main nonparametric tests and their particular uses. Biostatistical analysis is essential in dental research; dental research frequently deviates from the assumptions that underpin traditional parametric statistics. Nonparametric statistics are useful for studies with small sample sizes, nominal- or ordinal-level data, and non-normally distributed variables. These statistical tests make no assumptions about the sampled population. Nonparametric tests are statistical methods based on signs and ranks. For dental research to be conducted effectively and accurately, statistical approaches must be applied correctly. Therefore, dental researchers must understand the many statistical methods at their disposal and know when to use them.

Expression of miR-155 in monocytes of people with migraine: association with phenotype, disease severity and inflammatory profile

BACKGROUND

miR-155 is involved in the generation and maintenance of inflammation and pain, endothelial function and immune system homeostasis, all functions that are relevant for migraine. The present study aims to assess the levels of miR-155 in migraine subtypes (episodic and chronic) in comparison to age- and sex-matched healthy controls.

METHODS

This is a cross-sectional, controlled, study involving three study groups: I) episodic migraine (n = 52, EM), II) chronic migraine with medication overuse (n = 44, CM-MO), and III) healthy controls (n = 32, HCs). We assessed the interictal gene expression levels of miR-155, IL-1β, TNF-α, and IL-10 in peripheral blood monocytes using rtPCR. The monocytic differentiation toward the M1 (pro-inflammatory) or M2 (anti-inflammatory) phenotypes was assessed in circulating monocytes with flow cytometry analysis and cell sorting.

RESULTS

miR-155 gene expression was higher in CM-MO group (2.68 ± 2.47 Relative Quantification - RQ) when compared to EM group (1.46 ± 0.85 RQ, p = 0.006) and HCs (0.44 ± 0.18 RQ, p = 0.001). In addition, miR-155 gene expression was higher in EM group when compared to HCs (p = 0.001). A multivariate analysis confirmed the difference between EM and CM-MO groups after correction for age, sex, smoking habit, preventive treatment, aura, presence of psychiatric or other pain conditions. We found higher gene expression of IL-1β, TNF-α, and lower gene expression of IL-10 in migraine participants when compared to HCs (p = 0.001 for all comparisons). TNF-α and IL-10 genes alterations were more prominent in CM-MO when compared to EM participants (p = 0.001). miR-155 positively correlated with IL-1β (p = 0.001) and TNF-α (p = 0.001) expression levels. Finally, in people with CM-MO, we described an up-regulated percentage of events in both M1 and M2 monocytic profiles.

CONCLUSIONS

Our study shows for the first time a specific profile of activation of miR-155 gene expression levels in monocytes of selected migraine subpopulations, more pronounced in subjects with CM-MO. Interestingly, mir-155 expression correlated with markers of activation of the inflammatory and immune systems. The CM-MO subpopulation showed a peculiar increase of both pro-inflammatory and anti-inflammatory monocytes which worths further investigation.

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Altered immunity in migraine: a comprehensive scoping review

BACKGROUND

The pathogenesis of migraine remains unclear; however, a large body of evidence supports the hypothesis that immunological mechanisms play a key role. Therefore, we aimed to review current studies on altered immunity in individuals with migraine during and outside attacks.

METHODS

We searched the PubMed database to investigate immunological changes in patients with migraine. We then added other relevant articles on altered immunity in migraine to our search.

RESULTS

Database screening identified 1,102 articles, of which 41 were selected. We added another 104 relevant articles. We found studies reporting elevated interictal levels of some proinflammatory cytokines, including IL-6 and TNF-α. Anti-inflammatory cytokines showed various findings, such as increased TGF-β and decreased IL-10. Other changes in humoral immunity included increased levels of chemokines, adhesion molecules, and matrix metalloproteinases; activation of the complement system; and increased IgM and IgA. Changes in cellular immunity included an increase in T helper cells, decreased cytotoxic T cells, decreased regulatory T cells, and an increase in a subset of natural killer cells. A significant comorbidity of autoimmune and allergic diseases with migraine was observed.

CONCLUSIONS

Our review summarizes the findings regarding altered humoral and cellular immunological findings in human migraine. We highlight the possible involvement of immunological mechanisms in the pathogenesis of migraine. However, further studies are needed to expand our knowledge of the exact role of immunological mechanisms in migraine pathogenesis.

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.

Immediate-release niacin and a monounsaturated fatty acid-rich meal on postprandial inflammation and monocyte characteristics in men with metabolic syndrome

BACKGROUND & AIM

When considered separately, long-term immediate-release niacin and fatty meals enriched in monounsaturated fatty acids (MUFA) decrease postprandial triglycerides, but their effects on postprandial inflammation, which is common in individuals with metabolic syndrome, are less known. Moreover, successful combination is lacking and its impact on acute disorders of the innate immune cells in the metabolic syndrome remains unclear. Here, we aimed to establish the effects from combination with niacin of different fats [butter, enriched in saturated fatty acids (SFA), olive oil, enriched in MUFA, and olive oil supplemented with eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids] on plasma inflammatory markers and circulating monocyte subsets, activation and priming at the postprandial period in individuals with metabolic syndrome.

METHODS

A random-order within-subject crossover experiment was performed, in which 16 individuals with metabolic syndrome and 16 age-matched healthy volunteers took 2 g immediate-release niacin together with the corresponding fatty meal or a meal with no fat as control. In total, 128 postprandial curves were analysed. We sampled hourly over 6 h for plasma concentrations of soluble inflammatory markers and triglycerides. Circulating monocyte subsets (CD14/CD16 balance), activation (CCL2/CCR2 axis) and priming (M1/M2-like phenotype) at the time of postprandial hypertriglyceridemic peak were also addressed.

RESULTS

Dietary SFA (combined with niacin) promote postprandial excursions of circulating IL-6, IL-1β, TNF-α and CD14/CCR2-rich monocytes with a pro-inflammatory M1-like phenotype, particularly in individuals with metabolic syndrome. In contrast, dietary MUFA (combined with niacin) postprandially increased circulating CD16-rich monocytes with an anti-inflammatory M2-like phenotype. Omega-3 PUFA did not add to the effects of MUFA.

CONCLUSION

The co-administration of a single-dose of immediate-release niacin with a fatty meal rich in MUFA, in contrast to SFA, suppresses postprandial inflammation at the levels of both secretory profile and monocyte response in individuals with metabolic syndrome. These findings highlight a potential role of combining niacin and dietary MUFA for the homeostatic control of inflammation and the innate immune system, identifying a new search direction for the management of disorders associated with the metabolic syndrome.

Migraine and risk of rheumatoid arthritis: A systematic review and meta-analysis of observational studies

Background

Exposure to Migraine may be one of the risk factors for the onset of rheumatoid arthritis (RA), while the relationship between the two is debatable. In this study, the connection between migraine and the risk of RA was investigated using a systematic review and meta-analysis of the pertinent literature.

Methods

Up to July 2022, the PubMed, EMBASE, Web of Science (WOS), and scopus databases were employed to search for observational studies on the risk of RA in migraineurs. The effect sizes were pooled using a random-effects model or a fixed-effects model.

Results

Out of 2345 records, 5 studies (3 case and control studies and 2 cohort studies) were identified and included in the meta-analysis. According to a pooled analysis, migraine sufferers had a higher chance of developing RA (pooled adjusted effect estimate: 1.94, 95% confidence interval: 1.74-2.17; p < 0.01).

Conclusions

Migraine can be legitimately regarded as a risk factor for RA since this study demonstrated a relationship between migraine and RA. This conclusion should be treated with caution due to low power and precision. Rigorous design and larger sample sizes of studies are needed to verify the findings.