Hyperleptinemia increases the susceptibility of the cortex to generate cortical spreading depression

Molecular and Cellular Neurobiology of Spreading Depolarization/Depression and Migraine: A Narrative Review

Migraine is a prevalent neurological disorder, particularly among individuals aged 20-50 years, with significant social and economic impacts. Despite its high prevalence, the pathogenesis of migraine remains unclear. In this review, we provide a comprehensive overview of cortical spreading depolarization/depression (CSD) and its close association with migraine aura, focusing on its role in understanding migraine pathogenesis and therapeutic interventions. We discuss historical studies that have demonstrated the role of CSD in the visual phenomenon of migraine aura, along with modern imaging techniques confirming its propagation across the occipital cortex. Animal studies are examined to indicate that CSD is not exclusive to migraines; it also occurs in other neurological conditions. At the cellular level, we review how CSD is characterized by ionic changes and excitotoxicity, leading to neuronal and glial responses. We explore how CSD activates the trigeminal nervous system and upregulates the expression of calcitonin gene-related peptides (CGRP), thereby contributing to migraine pain. Factors such as genetics, obesity, and environmental conditions that influence the CSD threshold are discussed, suggesting potential therapeutic targets. Current treatments for migraine, including prophylactic agents and CGRP-targeting drugs, are evaluated in the context of their expected effects on suppressing CSD activity. Additionally, we highlight emerging therapies such as intranasal insulin-like growth factor 1 and vagus nerve stimulation, which have shown promise in reducing CSD susceptibility and frequency. By elucidating the molecular and cellular mechanisms of CSD, this review aims to enhance the understanding of migraine pathogenesis and support the development of targeted therapeutic strategies.

Metabolic Pathophysiology of Cortical Spreading Depression: A Review

Cortical spreading depression (CSD) is an electrophysiologic pathological state in which a wave of depolarization in the cerebral cortex is followed by the suppression of spontaneous neuronal activity. This transient spread of neuronal depolarization on the surface of the cortex is the hallmark of CSD. Numerous investigations have demonstrated that transmembrane ion transport, astrocytic ion clearing and fatigue, glucose metabolism, the presence of certain genetic markers, point mutations, and the expression of the enzyme responsible for the production of various arachidonic acid derivatives that participate in the inflammatory response, namely, cyclooxygenase (COX), all influence CSD. Here, we explore the associations between CSD occurrence in the cortex and various factors, including how CSD is related to migraines, how the glucose state affects CSD, the effect of TBI and its relationship with CSD and glucose metabolism, how different markers can be measured to determine the severity of CSD, and possible connections to oligemia, orexin, and leptin.

Elevation in body temperature may increase susceptibility to cortical spreading depression in a rat model

One characteristic of migraine is recurrent headache attacks, which are known to be induced by changes in climatic variables such as atmospheric pressure, humidity, and outside temperature. However, the relationship between temperature changes and migraine remains unclear. Therefore, we investigated the relationship between body temperature changes and cortical spreading depression (CSD) using KCl-induced rat models of CSD. We initially induced CSD under controlled conditions at a room temperature of 28°C on an operating table maintained at 37°C. Subsequently, we controlled the operating table temperature to induce a second round of CSD under conditions of either a 10 ± 1% increase or decrease in body temperature. We ensured 1 h rest period between the first and second inductions of CSD. The results indicated that the number of CSDs significantly increased after body temperature elevation (before, 8.8 ± 1.2 times vs. after, 13.4 ± 1.3 times; p = 0.0003). The mean percentage change in cerebral blood flow decreased after body temperature increased (before, 33.1 ± 2.4% vs. after, 18.2 ± 1.4%; p = 0.006). There were no significant changes in CSD after body temperature decreased. The susceptibility of the cortex to CSD may increase under conditions of elevated body temperature.

Migraine Duration as a Potential Amplifier of Obesity

Purpose

Migraine is a complex neurovascular disorder with obesity as a notable risk factor. This study aimed to investigate an under-researched area of the association between migraine duration and body composition.

Patients and Methods

Patients with migraine from a neurology outpatient department were enrolled and were categorized into four groups based on illness duration: 1 year, 1-5 years, 5-10 years, and >10 years. Patient demographics, blood biochemistry, and body composition data were collected and analyzed statistically.

Results

Patients with migraine were predominantly female, with lower education levels, significant work stress, poor sleep, and limited exercise. Longer migraine duration corresponded to increased obesity metrics. Notably, those patients with under 1 year of illness showed elevated blood lipid and liver function levels, whereas those with >10 years showed increased weight, waist circumference, body mass index, and fat content, despite higher physical activity. Significant positive correlation between obesity metrics and migraine duration was seen in patients who had migraine for >1 year.

Conclusion

Our findings indicate that protracted episodes of migraine could amplify obesity tendencies, underscoring the imperative of weight regulation in migraine intervention to diminish ensuing adiposity-associated hazards.

Association of obesity with headache among US children and adolescents: Evidence from NHANES 1999-2004

Background

Children and adolescents increasingly commonly suffer from obesity and headache. It has been confirmed that there is an association between obesity and headache in adults; however, evidence of such an association in paediatric populations is still controversial. Therefore, this study examined the relationship between obesity and headache among children and adolescents in the US.

Methods

The cross-sectional data of 3948 participants were obtained from the National Health and Nutrition Examination Survey 1999-2004. Weighted logistic regression models were applied to investigate the association between obesity and headache. Subgroup analysis stratified by sex and age was performed to explore the potential difference in the association of paediatric obesity with headache. The performance of paediatric obesity on headache was assessed by receiver operating characteristic (ROC) curve.

Results

The present study involved 3948 participants, of whom 713 (18.1%) had headache. Compared to those without headache, participants with headache tended to be girls and adolescents, have less calcium intake, and have higher levels of body mass index (BMI), C-reactive protein (CRP), serum ferritin and triglycerides (TGs) (all P < 0.05). After fully adjusting for potential confounders, the ORs with 95% CIs for headache were 1.03 (0.58-1.54) and 1.25 (0.68-2.30) for overweight and obese participants in comparison with normal-weight controls, respectively, implying no association of paediatric obesity with headache independent of other potential confounding factors. In addition, although higher odds of headache were noted in girls and adolescents (aged 10-17 years), no statistically significant difference was found across any subgroups. The area under the ROC (AUC) of paediatric obesity on headache was 0.634.

Conclusions

In summary, our study indicated that obesity is not associated with headache among US children and adolescents. Further prospective studies with larger sample size are needed to validate our findings.

Understanding the link between obesity and headache- with focus on migraine and idiopathic intracranial hypertension

BACKGROUND

Obesity confers adverse effects to every system in the body including the central nervous system. Obesity is associated with both migraine and idiopathic intracranial hypertension (IIH). The mechanisms underlying the association between obesity and these headache diseases remain unclear.

METHODS

We conducted a narrative review of the evidence in both humans and rodents, for the putative mechanisms underlying the link between obesity, migraine and IIH.

RESULTS

Truncal adiposity, a key feature of obesity, is associated with increased migraine morbidity and disability through increased headache severity, frequency and more severe cutaneous allodynia. Obesity may also increase intracranial pressure and could contribute to headache morbidity in migraine and be causative in IIH headache. Weight loss can improve both migraine and IIH headache. Preclinical research highlights that obesity increases the sensitivity of the trigeminovascular system to noxious stimuli including inflammatory stimuli, but the underlying molecular mechanisms remain unelucidated.

CONCLUSIONS

This review highlights that at the epidemiological and clinical level, obesity increases morbidity in migraine and IIH headache, where weight loss can improve headache morbidity. However, further research is required to understand the molecular underpinnings of obesity related headache in order to generate novel treatments.

The association between obesity and migraine and possible mechanisms of action: an integrative literature review

IntroductionObesity is a multifactorial disease and is defined by the excessive accumulation of adipose tissue that can cause harm to human health. The presence of obesity is an important risk factor for migraine chronification. However, not much is known about the link between the two diseases. MethodsIn this study, an integrative literature review was conducted to better understand the mechanisms of interaction between migraine and obesity. Therefore, a search of PubMed and the Virtual Health Library (VHL) was performed with the following keywords: enxaqueca e obesidade; enxaqueca e obesidade e inflamação; enxaqueca e obesidade e neuropeptídeos; migraine and obesity; migraine and obesity and inflammation; migraine and obesity and neuropeptides. ResultsThe search identified 22 articles. After reading and analyzing the articles, three thematic categories emerged: 1) Obesity as an Aggravating Factor for Migraine 2) Mechanisms Studied between Obesity and Migraine 3) The Effect of Weight Loss on Migraine Symptoms. ConclusionsThe chronic low-grade inflammation associated with obesity can cause a predisposition to migraine chronification. The abnormal secretion of adipokines, dysregulation of the sympathetic nervous system, and hypothalamic dysfunction have been suggested to be the main shared mechanisms between both diseases.

Metabolic Aspects of Migraine: Association With Obesity and Diabetes Mellitus

Migraine is a disabling neurovascular disorder, characterized by moderate to severe unilateral headaches, nausea, photophobia, and/or phonophobia, with a higher prevalence in women than in men, which can drastically affect the quality of life of migraine patients. In addition, this chronic disorder is related with metabolic comorbidities associated with the patient's lifestyle, including obesity and diabetes mellitus (DM). Beyond the personal and socioeconomic impact caused by migraine, obesity and DM, it has been suggested that these metabolic disorders seem to be related to migraine since: (i) they are a risk factor for developing cardiovascular disorders or chronic diseases; (ii) they can be influenced by genetic and environmental risk factors; and (iii) while clinical and epidemiological studies suggest that obesity is a risk factor for migraine, DM (i.e., type 1 and type 2 DM) have been reported to be either a protective or a risk factor in migraine. On this basis, and given the high worldwide prevalence of migraine, obesity, and DM, this article provides a narrative review of the current literature related to the association between the etiology and pathophysiology of migraine and these metabolic disorders, considering lifestyle aspects, as well as the possible involvement of neurotransmitters, neuropeptides, and/or sex hormones. While a link between migraine and metabolic disorders has been suggested, many studies are contradictory and the mechanisms involved in this association are not yet sufficiently established. Therefore, further research should be focused on understanding the possible mechanisms involved.

Trigeminal Pain Responses in Obese ob/ob Mice Are Modality-Specific

How obesity exacerbates migraine and other pain disorders remains unknown. Trigeminal nociceptive processing, crucial in migraine pathophysiology, is abnormal in mice with diet induced obesity. However, it is not known if this is also true in genetic models of obesity. We hypothesized that obese mice, regardless of the model, have trigeminal hyperalgesia. To test this, we first evaluated trigeminal thermal nociception in leptin deficient (ob/ob) and control mice using an operant thermal assay. Unexpectedly, we found significant hypoalgesia in ob/ob mice. Because thermal hypoalgesia also occurs in mice lacking the transient receptor potential vanilloid 1 channel (TRPV1), we tested capsaicin-evoked trigeminal nociception. Ob/ob and control mice had similar capsaicin-evoked nocifensive behaviors, but ob/ob mice were significantly less active after a facial injection of capsaicin than were diet-induced obese mice or lean controls. Conditioned place aversion in response to trigeminal stimulation with capsaicin was similar in both genotypes, indicating normal negative affect and pain avoidance. Supporting this, we found no difference in TRPV1 expression in the trigeminal ganglia of ob/ob and control mice. Finally, we assessed the possible contribution of hyperphagia, a hallmark of leptin deficiency, to the behavior observed in the operant assay. Ob/ob and lean control mice had similar reduction of intake when quinine or capsaicin was added to the sweetened milk, excluding a significant contribution of hyperphagia. In summary, ob/ob mice, unlike mice with diet-induced obesity, have trigeminal thermal hypoalgesia but normal responses to capsaicin, suggesting specificity in the mechanisms by which leptin acts in pain processing.

Obesity and Migraine in Childhood

PURPOSE OF REVIEW

The purpose of this work was to review the current literature on the epidemiology and pathophysiology of pediatric obesity and migraine, underlying pathogenic mechanisms that may explain the association between the two disorders, and the effects of treatment.

RECENT FINDINGS

In children and adolescents, the bulk of the available data support an association between obesity and headache disorders in general, though a small number of studies contradict these findings. Relative to the adult population, however, few studies have focused specifically on migraine, and no wide-ranging meta-analyses have been conducted to date. It seems that the pathophysiology of obesity and migraine in adults holds true for the pediatric population as well. The association between obesity and migraine in the pediatric population is likely to be multifactorial and to involve both central and peripheral mechanisms. More attention is currently being addressed to the role of the hypothalamus and the bioactive neurotransmitters and neuropeptides that modulate energy homeostasis, namely serotonin, orexin, and the adiponectins, in migraine. A few innovative studies have demonstrated some benefit for migraine from weight reduction treatments such as exercise and lifestyle management. Many open questions remain regarding the modifiable nature of the obesity-migraine relationship and its implications in clinical practice. Further studies of these issues are needed.

The role of leptin as a biomarker in the relationship between periodontitis and chronic migraine

AIM

To evaluate the prevalence of periodontitis (CP) and its contribution to serum leptin levels in chronic migraine (CM).

MATERIAL AND METHODS

In this case-control study, we included 150 subjects divided into healthy controls (n = 58) and CM patients (n = 92). Demographic, neurological, clinical data as well as full-mouth periodontal records were obtained. Serum leptin levels were measured by ELISA technique.

RESULTS

Both the prevalence of CP and mean serum leptin levels were significantly higher in patients with CM in comparison with controls (57.6% versus 36.2%, p = .01 and 16.4 versus 7.2 ng/ml, p < .0001, respectively). Patients from the CM group who had CP showed significantly higher leptin concentrations than CM patients without CP (19.8 versus 11.8 ng/ml, p < .0001). Multivariable linear regression analysis showed that CP was an independent contributor to raised leptin levels in CM patients (R²  = 0.270, p = 0.013).

CONCLUSIONS

CP is prevalent in CM patients and when present it contributes to elevated serum leptin levels, independently of other confounding factors. Therefore, it seems that CP via leptin could be involved in the process of migraine chronification.

Chronic migraine: risk factors, mechanisms and treatment

Chronic migraine has a great detrimental influence on a patient's life, with a severe impact on socioeconomic functioning and quality of life. Chronic migraine affects 1-2% of the general population, and about 8% of patients with migraine; it usually develops from episodic migraine at an annual conversion rate of about 3%. The chronification is reversible: about 26% of patients with chronic migraine go into remission within 2 years of chronification. The most important modifiable risk factors for chronic migraine include overuse of acute migraine medication, ineffective acute treatment, obesity, depression and stressful life events. Moreover, age, female sex and low educational status increase the risk of chronic migraine. The pathophysiology of migraine chronification can be understood as a threshold problem: certain predisposing factors, combined with frequent headache pain, lower the threshold of migraine attacks, thereby increasing the risk of chronic migraine. Treatment options include oral medications, nerve blockade with local anaesthetics or corticoids, and neuromodulation. Well-defined diagnostic criteria are crucial for the identification of chronic migraine. The International Headache Society classification of chronic migraine was recently updated, and now allows co-diagnosis of chronic migraine and medication overuse headache. This Review provides an up-to-date overview of the classification of chronic migraine, basic mechanisms and risk factors of migraine chronification, and the currently established treatment options.

High leptin levels are associated with migraine with aura

Background Migraine is a prevalent disorder characterised by recurrent headache attacks preceded or accompanied by aura in a subgroup of patients. Migraine often occurs together with major depressive disorder (MDD). Alterations of adipokine levels have been reported both in migraine and in MDD. In this cross-sectional study, we aimed to assess the associations between serum leptin and adiponectin levels and migraine or migraine subtypes. Analyses were adjusted for a lifetime history of MDD in order to investigate the association between adipokines and migraine under consideration of depression status. Methods We included 3025 participants from the CoLaus/PsyCoLaus study. The impact of leptin and adiponectin levels on a diagnosis of migraine was analysed by binary regression analyses, adjusting for variables known to influence adipokine levels. Subgroup analyses were conducted based on the presence of aura. Results Crude leptin levels were significantly higher in subjects with migraine than controls (Mann-Whitney U = 515,102, p = 6 × 10^-7). When performing adjusted analyses, leptin levels were found to be significantly higher in subjects with migraine (odds ratio = 1.22, p = 0.024) and migraine with aura (odds ratio = 1.34, p = 0.004). Conclusion High leptin levels might play a role in the pathogenesis of migraine and migraine with aura.

Adipokines and Migraine: A Systematic Review

BACKGROUND

Migraine is comorbid with obesity. Recent research suggests an association between migraine and adipocytokines, proteins that are predominantly secreted from adipose tissue and which participate in energy homeostasis and inflammatory processes.

OBJECTIVES

In this review, we first briefly discuss the association between migraine and obesity and the importance of adipose tissue as a neuroendocrine organ. We then present a systematic review of the extant literature evaluating circulating levels of adiponectin and leptin in those with migraine.

METHODS

A search of the PubMed database was conducted using the keywords "migraine," "adiponectin," and "leptin." In addition reference lists of relevant articles were reviewed for possible inclusion. English language studies published between 2005 and 2015 evaluating circulating blood concentration of adiponectin or leptin in those with migraine were included.

CONCLUSIONS

While the existing data are suggestive that adipokines may be associated with migraine, substantial study design differences and conflicting results limit definitive conclusions. Future research utilizing carefully considered designs and methodology is warranted. In particular careful and systematic characterization of pain states at the time of samples, as well as systematic consideration of demographic (e.g., age, sex) and other vital covariates (e.g., obesity status, lipids) are needed to determine if adipokines play a role in migraine pathophysiology and if any adipokine represents a viable, novel migraine biomarker, or drug target.