Leptin as a metabolic link to multiple sclerosis

Randomised controlled trial of intermittent calorie restriction in people with multiple sclerosis

BACKGROUND

Calorie restriction (CR) ameliorates preclinical models of multiple sclerosis (MS) via multiple mechanisms. These include decreased leptin, a proinflammatory adipokine, but mechanistic studies in humans are lacking. Tests of daily and intermittent CR (iCR) in people with MS (pwMS) showed improvements in fatigue and well-being measures. This trial studied the effects of 12-week iCR on metabolic, immunological, and clinical outcomes in pwMS.

METHOD

Relapsing-remitting MS participants were randomised to iCR or a control group. Study visits were conducted at baseline, 6 and 12 weeks. The primary outcome was reduction in serum leptin levels at 12 weeks. Feasibility and safety were assessed by diet adherence and adverse events (AEs). Secondary outcomes included changes in anthropometric and body composition measures, metabolic and immunologic profiling, and clinical measures. Mixed effects linear regression models were used to evaluate outcome differences between and within groups over time.

RESULTS

Forty-two pwMS were randomised, 34 completed the study (17/group). Leptin serum levels at 12 weeks were significantly lower in the iCR versus the control group (mean decrease -6.98 µg/dL, 95% CI: -28.02 to 14.06; p=0.03). Adherence to iCR was 99.5% and 97.2% at 6 and 12 weeks, respectively, and no serious AEs were reported. An increase in blood CD45RO+ regulatory T-cell numbers was seen after 6 weeks of iCR. Exploratory cognitive testing demonstrated a significant improvement in the Symbol Digit Modality Test Score in the iCR group at 12 weeks.

CONCLUSIONS

iCR has the potential to benefit metabolic and immunologic profiles and is safe and feasible in pwMS.

TRIAL REGISTRATION NUMBER

NCT03539094 .

The complex relationship between obesity and neurodegenerative diseases: an updated review

Obesity is a global epidemic, affecting roughly 30% of the world's population and predicted to rise. This disease results from genetic, behavioral, societal, and environmental factors, leading to excessive fat accumulation, due to insufficient energy expenditure. The adipose tissue, once seen as a simple storage depot, is now recognized as a complex organ with various functions, including hormone regulation and modulation of metabolism, inflammation, and homeostasis. Obesity is associated with a low-grade inflammatory state and has been linked to neurodegenerative diseases like multiple sclerosis (MS), Alzheimer's (AD), and Parkinson's (PD). Mechanistically, reduced adipose expandability leads to hypertrophic adipocytes, triggering inflammation, insulin and leptin resistance, blood-brain barrier disruption, altered brain metabolism, neuronal inflammation, brain atrophy, and cognitive decline. Obesity impacts neurodegenerative disorders through shared underlying mechanisms, underscoring its potential as a modifiable risk factor for these diseases. Nevertheless, further research is needed to fully grasp the intricate connections between obesity and neurodegeneration. Collaborative efforts in this field hold promise for innovative strategies to address this complex relationship and develop effective prevention and treatment methods, which also includes specific diets and physical activities, ultimately improving quality of life and health.

Musical therapy attenuates neuroma pain by modifying leptin expression

BACKGROUND

Accumulating evidence reveals that music therapy appears to help patients with pain. However, there is a limited understanding of the underlying mechanisms. Several studies indicate that leptin level has a crucial relationship with acute and chronic pain. Herein, we evaluated the effects of music stimulation and the potential roles of adipokines (leptin) in pain behaviors.

METHODS

We used a tibial neuroma transposition (TNT) rat model to mimic neuroma pain. Adult male Sprague-Dawley rats were randomly assigned to one of the three groups (n = 6):group 1 (GC), TNT with white noise; group 2(GM), TNT with music; and group 3(GH), TNT. White noise and music stimulation was given once a day following surgery until the end of the study (42^nd day). Pain behavioral tests were carried out before surgery and on the 3^rd, 10^th, 14^th, 21^st, 28^th, 35^th, and 42^nd days after surgery. At the end of the observation period, we analyzed the histological samples of blood, spinal cord, and prefrontal cortex to investigate the role of leptin in pain behaviors modulated by white noise and sound stimulation.

RESULT

Music therapy might improve the pain of TNT rats. Music stimulation ameliorated paw withdrawal thermal latency (PWTL) from the 3^rd day after the surgery while the mechanical pain was improved 21 days after the operation.Music stimulation also increased leptin expression in the spinal cord, prefrontal cortex.White noise had no obvious effect.

CONCLUSION

Music therapy might improve the pain of TNT rats. Besides, music stimulation ameliorated TNT-induced pain behaviors and affected leptin expression.

The impact of bariatric surgery on disease activity and progression of multiple sclerosis: A nationwide matched cohort study

BACKGROUND

Surgical outcomes in patients with multiple sclerosis (MS) following metabolic surgery appear to be similar compared to those of the general bariatric population.

OBJECTIVE

To study the impact of metabolic surgery on the clinical course of MS.

METHODS

Using data from the Scandinavian Obesity Surgery Registry and the Swedish Multiple Sclerosis register, we compared disease outcomes in 122 cases of MS who had undergone metabolic surgery with those of 122 cases of MS without surgery, matched by a two-staged Propensity score match, including age at disease onset, sex, MS phenotype, body mass index, and preoperative severity of MS as measured by the Expanded Disability Status Scale.

RESULTS

The time to 6-month confirmed disability progression during the first five years postbaseline was shorter among the surgical patients (hazard ratio (HR) = 2.31, 95% confidence interval (CI) = 1.09-4.90; p = 0.03). No differences were observed regarding postoperative annual relapse rate (p = 0.24) or time to first postoperative relapse (p = 0.52).

CONCLUSION

Although metabolic surgery appears to be a safe and efficient treatment of obesity in patients with MS, the clinical course of the disease might be negatively affected. Long-term nutritional follow-up after surgery and supplementation maintenance are crucial, particularly among those with preoperative deficits.

Whole Exome Sequencing in Multi-Incident Families Identifies Novel Candidate Genes for Multiple Sclerosis

Multiple sclerosis (MS) is a degenerative disease of the central nervous system in which auto-immunity-induced demyelination occurs. MS is thought to be caused by a complex interplay of environmental and genetic risk factors. While most genetic studies have focused on identifying common genetic variants for MS through genome-wide association studies, the objective of the present study was to identify rare genetic variants contributing to MS susceptibility. We used whole exome sequencing (WES) followed by co-segregation analyses in nine multi-incident families with two to four affected individuals. WES was performed in 31 family members with and without MS. After applying a suite of selection criteria, co-segregation analyses for a number of rare variants selected from the WES results were performed, adding 24 family members. This approach resulted in 12 exonic rare variants that showed acceptable co-segregation with MS within the nine families, implicating the genes MBP, PLK1, MECP2, MTMR7, TOX3, CPT1A, SORCS1, TRIM66, ITPR3, TTC28, CACNA1F, and PRAM1. Of these, three genes (MBP, MECP2, and CPT1A) have been previously reported as carrying MS-related rare variants. Six additional genes (MTMR7, TOX3, SORCS1, ITPR3, TTC28, and PRAM1) have also been implicated in MS through common genetic variants. The proteins encoded by all twelve genes containing rare variants interact in a molecular framework that points to biological processes involved in (de-/re-)myelination and auto-immunity. Our approach provides clues to possible molecular mechanisms underlying MS that should be studied further in cellular and/or animal models.

Leptin signaling and leptin resistance

With the prevalence of obesity and associated comorbidities, studies aimed at revealing mechanisms that regulate energy homeostasis have gained increasing interest. In 1994, the cloning of leptin was a milestone in metabolic research. As an adipocytokine, leptin governs food intake and energy homeostasis through leptin receptors (LepR) in the brain. The failure of increased leptin levels to suppress feeding and elevate energy expenditure is referred to as leptin resistance, which encompasses complex pathophysiological processes. Within the brain, LepR-expressing neurons are distributed in hypothalamus and other brain areas, and each population of the LepR-expressing neurons may mediate particular aspects of leptin effects. In LepR-expressing neurons, the binding of leptin to LepR initiates multiple signaling cascades including janus kinase (JAK)-signal transducers and activators of transcription (STAT) phosphatidylinositol 3-kinase (PI3K)-protein kinase B (AKT), extracellular regulated protein kinase (ERK), and AMP-activated protein kinase (AMPK) signaling, etc., mediating leptin actions. These findings place leptin at the intersection of metabolic and neuroendocrine regulations, and render leptin a key target for treating obesity and associated comorbidities. This review highlights the main discoveries that shaped the field of leptin for better understanding of the mechanism governing metabolic homeostasis, and guides the development of safe and effective interventions to treat obesity and associated diseases.

The Role of Diet and Interventions on Multiple Sclerosis: A Review

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS) characterized by inflammation and neurodegeneration. The most prominent clinical features include visual loss and sensorimotor symptoms and mainly affects those of young age. Some of the factors affecting its pathogenesis are genetic and/or environmental including viruses, smoking, obesity, and nutrition. Current research provides evidence that diet may influence MS onset, course, and quality of life of the patients. In this review, we address the role of nutrition on MS pathogenesis as well as dietary interventions that show promising beneficial results with respect to MS activity and progression. Investigation with large prospective clinical studies is required in order to thoroughly evaluate the role of diet in MS.

Modifying Diet and Exercise in MS (MoDEMS): Study design and protocol for a telehealth weight loss intervention for adults with obesity & Multiple Sclerosis

Weight loss improves overall health, and reduces inflammation, risk of stroke, heart attack, diabetes, certain cancers, and death among individuals with obesity. Weight loss also improves mobility, increases stamina, and elevates mood. Between 25 and 33% of people with Multiple Sclerosis (pwMS) have obesity. Multiple Sclerosis (MS) and obesity are independently associated with reduced mobility, increased fatigue, and depression. Most behavioral weight loss trials exclude individuals with neurologic disease. Consequently, few studies have examined the effects of weight loss on symptom presentation and health outcomes among pwMS and obesity. This is the first study examining the efficacy of a comprehensive behavioral weight loss intervention designed specifically for pwMS. The purpose of this study is to develop and assess the efficacy of a telehealth administered weight loss intervention tailored for pwMS. Additionally, we aim to determine if weight loss reduces physical and emotional symptoms in individuals with obesity and MS. We will enroll 70 pwMS in a wait-list crossover trial to examine the efficacy of our intervention. If successful, findings will help determine whether we can help participants lose clinically significant weight - and whether weight loss among pwMS and overweight/obesity reduces fatigue, and improves mobility, mood, and quality of life.

Obesity and Multiple Sclerosis-A Multifaceted Association

BACKGROUND

Given the common elements in the pathophysiological theories that try to explain the appearance and evolution of obesity and multiple sclerosis, the association between the two pathologies has become an increasingly researched topic in recent years. On the one hand, there is the chronic demyelinating inflammation caused by the autoimmune cascade of multiple sclerosis, while on the other hand, according to the latest research, it has been shown that obesity shares an inflammatory component with most chronic diseases.

METHODS

The authors performed independent research of the available literature in the most important electronic databases (PubMed, Google Scholar, Embase, and Science Direct) in February 2021. After applying the exclusion criteria, the reviewers focused on the most relevant articles published during the last 10 years with respect to epidemiology and pathophysiology.

RESULTS

The data presented are a step forward in trying to elucidate the intricate relationship between obesity and MS, especially the causal relationship between childhood and adolescent obesity and MS, focusing on the epidemiological associations observed in the most relevant observational studies conducted in recent years. In the second part, the authors comment on the latest findings related to the pathophysiological mechanisms that may explain the correlations between obesity and multiple sclerosis, focusing also on the role of adipokines.

CONCLUSIONS

Based on available epidemiological data, obesity in early life appears to be strongly associated with a higher risk of MS development, independent of other risk factors. Although much research has been done on the pathophysiology of obesity, MS, their possible common mechanism, and the role of adipokines, further studies are needed in order to explain what remains unknown. No relevant data were found regarding the association between obesity, disability (high EDSS score), and mortality risk in MS patients. Thus, we consider that this topic should be elucidated in future research.

Association study of rs7799039, rs1137101 and rs8192678 gene variants with disease susceptibility/severity and corresponding LEP, LEPR and PGC1A gene expression in multiple sclerosis

BACKGROUND

Leptin (LEP), leptin receptor (LEPR) and peroxisome proliferator-activated receptor gamma co-activator 1-alpha (PGC1A) are involved in the pathogenesis of multiple sclerosis (MS) by affecting the inflammatory response and reactive oxygen species production. LEP rs7799039 and LEPR rs1137101 genetic variants modify the serum LEP levels and PGC1A rs8192678 alters the PGC1A activity. The study objective was to explore the associations of these variants with susceptibility to MS, disease course/clinical parameters and also with peripheral blood mononuclear cell expression of the target genes and plasma LEP concentrations, in the study subjects.

METHODS

The study groups included 528 patients with MS and 429 controls. TaqMan® assays were used for genotyping and gene expression quantification. The Chi-square, parametric and nonparametric tests and simple/multiple logistic regression were performed for the statistical analysis of data.

RESULTS

A multiple logistic regression model including all three investigated variants, applied to patients (RRMS + SPMS) and controls, showed that PGC1A rs8192678 minor allele had an increased risk for the occurrence of disease, with OR (95%CI) = 1,32 (1,01-1,73), P = 0,04. Between-effect of gender and LEPR variant on the multiple sclerosis severity score (MSSS) was identified (P = 0,005). In male patients (relapsing-remitting and secondary progressive), LEPR minor allele carriers had increased MSSS (GG + AG vs AA, median (minimum-maximum) = 5,38 (0,64-9,88) vs 4,27 (0,78-9,63); P = 0,01, P_adj = 0,03). In relapsing-remitting patients LEP rs7799039 affected the LEP gene expression (P = 0,006; P_adj = 0,04).

CONCLUSION

The current findings implicate an impact of investigated genetic variants on the pathogenesis of MS.

Bariatric Surgery-Associated Myelopathy

Bariatric surgery is gaining acceptance as an efficient treatment modality for adults and adolescents with morbid obesity. The early postbariatric period has the potential to induce an immunomodulatory imbalance due to the development or worsening of nutritional deficiencies, changes in hormonal balance (specifically after sleeve gastrectomy), and a shift in the proinflammatory cytokine profile along with a major change in the gut microbiome and permeability. These changes may induce encephalomyelitic T cell activity, change neural barrier permeability, and induce gut dysbioisis, favoring a proinflammatory metabolic profile. Such changes, in genetically prone individuals or those with additional risk factors, may lead to the development of myelopathy, particularly MS. Key Message: Postbariatric myelopathy is rare but should be considered in bariatric patients with relevant complaints in the postoperative period.

Obesity and the risk of Multiple Sclerosis. The role of Leptin

OBJECTIVE

To investigate the effects of leptin on different T-cell populations, in order to gain more insight into the link between leptin and obesity.

METHODS

Three hundred and nine RRMS patients and 322 controls participated in a cross-sectional survey, to confirm whether excess weight/obesity in adolescence or early adulthood increased the risk of MS. Serum leptin levels were determined by ELISA. MBP_83-102 , and MOG_63-87 peptide-specific T cells lines were expanded from peripheral blood mononuclear cells. Leptin receptor expression was measured by RT-PCR and flow cytometry. Bcl-2, p-STAT3, pERK1/2, and p27^kip1 expression were assayed using ELISA, and apoptosis induction was determined by Annexin V detection. Cytokines were assessed by ELISPOT and ELISA, and regulatory T cells (Tregs) by flow cytometry.

RESULTS

Logistic regression analysis, showed excess weight at age 15, and obesity at 20 years of age increased MS risk (OR = 2.16, P = 0.01 and OR = 3.9, P = 0.01). Leptin levels correlated with BMI in both groups. The addition of Leptin increased autoreactive T-cell proliferation, reduced apoptosis induction, and promoted proinflammatory cytokine secretion. Obese patients produced more proinflammatory cytokines compared to overweight/normal/underweight subjects. Inverse correlation was found between leptin levels and circulating Treg cells (r = -0.97, P < 0.0001). Leptin inhibited Treg proliferation. Effects of leptin on CD4⁺ CD25^- effector T cells were mediated by increased STAT3 and ERK1/2 phosphorylation, and down modulation of the cell cycle inhibitor P27^kip1 . In contrast, leptin effects on Tregs resulted from decreased phosphorylation of ERK1/2 and upregulation of p27^kip1 .

INTERPRETATION

Leptin promotes autoreactive T-cell proliferation and proinflammatory cytokine secretion, but inhibits Treg-cell proliferation.

JAK2 Mediates the Regulation of Pept1 Expression by Leptin in the Grass Carp (Ctenopharyngodon idella) Intestine

Oligopeptide transporter 1 (Pept1) is located on the brush border membrane of the intestinal epithelium and plays an important role in dipeptide and tripeptide absorption from protein digestion. In this study, we cloned and characterized the cDNA sequence of Janus kinase 2 (JAK2) from Ctenopharyngodon idella. The expression patterns of JAK2 in various tissues and developmental stages were characterized by quantitative real-time PCR (qRT-PCR). The mRNA expression levels of JAK2 and Pept1 regulated by leptin in the intestine were also analyzed in vitro and in vivo. The cDNA sequence of JAK2 is 3378 bp in length, and the mRNA of JAK2 was broadly expressed in all tissues and embryonic stages of C. idella analyzed. In addition, we found that leptin regulated expression of JAK2 and Pept1 in the intestine; Pept1 expression was down-regulated by the JAK2 inhibitor AG490 in vivo and in vitro. Furthermore, luciferase experiments showed that overexpression of the JAK2 gene significantly upregulated the activity of the Pept1 5′ regulatory sequence in C. idella. In conclusion, these results may help in elucidating the regulatory effect of the leptin-mediated JAK2 pathway on intestinal Pept1 expression in C. idella and the molecular mechanism of peptide transport by the intestinal transporter Pept1 in fishes.

Leptin: an unappreciated key player in SLE

Leptin is the forerunner of the adipokine superfamily and plays a key role in regulating energy expenditure and neuroendocrine function. Researches into leptin put emphasize not only on the metabolic role but also its immunoregulatory effect on immune response through immunocyte activation and cytokine secretion. Leptin acts on receptors that are widespread throughout the body and that are expressed across many tissue types. As a consequence, the abnormal expression of leptin has been found to correlate with a number of diseases, including cancers, autoimmune diseases, and cardiovascular diseases. The significance of leptin in the development of autoimmune diseases is becoming increasingly prominent. Systemic lupus erythematosus (SLE) is a severe atypical autoimmune disease that causes damage to multiple organ systems. It is characterised by the following: impaired clearance of apoptotic cells, loss of tolerance to self-antigens, aberrant activation of T cells and B cells, and chronic inflammation. The heightened immunocyte response in SLE means that these physiological systems are particularly vulnerable to regulation by leptin in addition to being of great significance to the research field. Our current review provides insight into the regulatory roles that leptin plays on immune effector cells in SLE.

Lifestyle-based modifiable risk factors in multiple sclerosis: review of experimental and clinical findings

Multiple sclerosis (MS) is a lifelong inflammatory and neurodegenerative disease influenced by multiple lifestyle-based factors. We provide a narrative review of the effects of modifiable risk factors that are identified as being associated with risk to develop MS and/or influencing the future clinical disease outcomes. The emerging data regarding the beneficial effects of diet modifications and exercise are further reviewed. In contrast, obesity and comorbid cardiovascular diseases are associated with increased MS susceptibility and worse disease progression. In addition, the potential influence of smoking, coffee and alcohol consumption on MS onset and disability development are discussed. Successful management of the modifiable risk factors may lead to better long-term outcomes and improve patients' quality of life. MS specialists should participate in educating and facilitating lifestyle-based modifications as part of their neurological consults.

Lifestyle and Environmental Factors in Multiple Sclerosis

Lifestyle and environmental factors potently influence the risk of multiple sclerosis (MS), because genetic predisposition only explains a fraction of the risk increase. There is strong evidence for associations of Epstein-Barr virus (EBV) infection, smoking, sun exposure/vitamin D, and adolescent obesity to risk of MS. There is also circumstantial evidence on organic solvents and shift work, all associate with greater risk, although certain factors like nicotine, alcohol, and a high coffee consumption associate with a reduced risk. Certain factors, smoking, EBV infection, and obesity interact with human leukocyte antigen (HLA) risk genes, arguing for a pathogenic pathway involving adaptive immunity. There is a potential for prevention, in particular for people at greater risk such as relatives of individuals with MS. All of the described factors for MS may influence adaptive and/or innate immunity, as has been argued for MS risk gene variants.

Impact of sex hormones on immune function and multiple sclerosis development

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) affecting young people and leading to demyelination and neurodegeneration. The disease is clearly more common in women, in whom incidence has been rising. Gender differences include: earlier disease onset and more frequent relapses in women; and faster progression and worse outcomes in men. Hormone-related physiological conditions in women such as puberty, pregnancy, puerperium, and menopause also exert significant influence both on disease prevalence as well as on outcomes. Hormonal and/or genetic factors are therefore believed to be involved in regulating the course of disease. In this review, we discuss clinical evidence for the impact of sex hormones (estrogens, progesterone, prolactin, and testosterone) on MS and attempt to elucidate the hormonal and immunological mechanisms potentially underlying these changes. We also review current knowledge on the relationship between sex hormones and resident CNS cells and provide new insights in the context of MS. Understanding these molecular mechanisms may contribute to the development of new and safer treatments for both men and women.

Serum levels of leptin and adiponectin are not associated with disease activity or treatment response in multiple sclerosis

Adipokines secreted by fatty tissue have inflammatory properties and are suggested biomarkers of MS disease activity. To assess this, 88 MS patients were followed with nine repeated measurements of leptin and adiponectin and 12 magnetic resonance imaging (MRI) scans for two years; six months without any immunomodulatory treatment followed by 18 months during interferon-beta (IFNB) treatment. Serum levels of leptin dropped and adiponectin increased upon initiation of IFNB-therapy, but were not associated with clinical or MRI disease activity or with treatment response. Our findings indicate that leptin and adiponectin are not useful as biomarkers of MS disease activity.

Insights into the Mechanisms That May Clarify Obesity as a Risk Factor for Multiple Sclerosis

PURPOSE OF REVIEW

The proportion to which genetic and environmental factors contribute to the etiology of multiple sclerosis (MS) is still incompletely understood. An interesting association between MS etiology and obesity has recently been shown although the mechanisms underlying this association are still unknown. We propose deregulated gut microbiota and increased leptin levels as possible mechanisms underlying MS etiology in obese individuals.

RECENT FINDINGS

Alterations in the human gut microbiota and leptin levels have recently been established as immune modulators in both MS patients and obese individuals. A resemblance between pro-inflammatory bacterial profiles in MS and obese individuals was observed. Furthermore, elevated leptin levels push the immune system towards a more pro-inflammatory state and inhibit the regulatory immune response. Deregulated gut microbiota and elevated leptin levels may explain the increased risk of developing MS in obese individuals. Further research to confirm causality is warranted.

Gender-Specific Association of Leptin and Adiponectin Genes With Multiple Sclerosis

BACKGROUND

Adipocytokines such as leptin (LEP) and adiponectin (ADIPOQ) represent a link between metabolism, nutritional status and immune responses. The present study aimed to determine the possible association between single nucleotide polymorphisms of LEP and ADIPOQ genes with multiple sclerosis (MS).

MATERIALS AND METHODS

Single nucleotide polymorphisms in LEP (rs2167270 or 19G > A and rs7799039 or -2,548G > A) and ADIPOQ (rs1501299 or +276G > T and rs266729 or -11,377C > G) were genotyped in 305 patients and 255 healthy individuals using polymerase chain reaction-restriction fragment length polymorphism. Sera levels of leptin and adiponectin were measured using enzyme-linked immunosorbent assay.

RESULTS

The frequencies of low leptin producer rs2167270GG genotype and rs2167270G allele were significantly lower in patients with MS compared to those of controls (for GG genotype: 39.7% and 49.8%, respectively; P = 0.01; for G allele: 63.3% and 68.8%, respectively; P = 0.05). Both polymorphisms in ADIPOQ did not show any significant association with disease susceptibility, though after gender categorization the frequency of high adiponectin producer rs1501299TT genotype and rs1501299T allele were significantly higher in male controls compared to male patients (TT genotype: P = 0.006; T allele: P = 0.006). Additionally, rs1501299TT genotype in ADIPOQ was associated with susceptibility to primary progressive multiple sclerosis (PP-MS) (P = 0.02). Moreover, while the sera levels of leptin were only different between male patients and controls (P = 0.05), adiponectin levels were significantly higher in total and female healthy controls (P < 0.001, P = 0.002, respectively).

CONCLUSIONS

Our findings provide evidence to support the hypothesis that functional ADIPOQ and LEP gene polymorphisms are associated with susceptibility to MS and its clinical forms.

A systems medicine approach reveals disordered immune system and lipid metabolism in multiple sclerosis patients

Identification of autoimmune processes and introduction of new autoantigens involved in the pathogenesis of multiple sclerosis (MS) can be helpful in the design of new drugs to prevent unresponsiveness and side effects in patients. To find significant changes, we evaluated the autoantibody repertoires in newly diagnosed relapsing-remitting MS patients (NDP) and those receiving disease-modifying therapy (RP). Through a random peptide phage library, a panel of NDP- and RP-specific peptides was identified, producing two protein data sets visualized using Gephi, based on protein--protein interactions in the STRING database. The top modules of NDP and RP networks were assessed using Enrichr. Based on the findings, a set of proteins, including ATP binding cassette subfamily C member 1 (ABCC1), neurogenic locus notch homologue protein 1 (NOTCH1), hepatocyte growth factor receptor (MET), RAF proto-oncogene serine/threonine-protein kinase (RAF1) and proto-oncogene vav (VAV1) was found in NDP and was involved in over-represented terms correlated with cell-mediated immunity and cancer. In contrast, transcription factor RelB (RELB), histone acetyltransferase p300 (EP300), acetyl-CoA carboxylase 2 (ACACB), adiponectin (ADIPOQ) and phosphoenolpyruvate carboxykinase 2 mitochondrial (PCK2) had major contributions to viral infections and lipid metabolism as significant events in RP. According to these findings, further research is required to demonstrate the pathogenic roles of such proteins and autoantibodies targeting them in MS and to develop therapeutic agents which can ameliorate disease severity.

Why monkeys do not get multiple sclerosis (spontaneously): An evolutionary approach

The goal of this review is to apply an evolutionary lens to understanding the origins of multiple sclerosis (MS), integrating three broad observations. First, only humans are known to develop MS spontaneously. Second, humans have evolved large brains, with characteristically large amounts of metabolically costly myelin. This myelin is generated over long periods of neurologic development—and peak MS onset coincides with the end of myelination. Third, over the past century there has been a disproportionate increase in the rate of MS in young women of childbearing age, paralleling increasing westernization and urbanization, indicating sexually specific susceptibility in response to changing exposures. From these three observations about MS, a life history approach leads us to hypothesize that MS arises in humans from disruption of the normal homeostatic mechanisms of myelin production and maintenance, during our uniquely long myelination period. This review will highlight under-explored areas of homeostasis in brain development, that are likely to shed new light on the origins of MS and to raise further questions about the interactions between our ancestral genes and modern environments.

Fatty acid binding protein-4 is associated with disability in multiple sclerosis patients

BACKGROUND

Increased adiposity is a risk factor for multiple sclerosis (MS) and is associated with increased disability scores. Adipokines may mediate the effects of adiposity on MS disease course.

OBJECTIVE

The objective of this study is to examine the association between the adipokines (leptin and fatty acid binding protein-4, FABP4) and clinical course in individuals with MS.

METHODS

Subjects (18-65 years) with relapsing-remitting MS or clinically isolated syndrome and <10 year disease duration were selected from a longitudinal clinical study. Cross-sectional and longitudinal models assessed the relationship between two adipokines (leptin and FABP4) and disease severity in women and men, adjusting for age, disease duration and disease type, Vitamin D level, testosterone level, and as well by body mass index (BMI).

RESULTS

Mean age of subjects ( N = 163, 56% women) was 39.3 years. Higher FABP4 levels were associated with higher Expanded Disability Status Scale (EDSS) scores in women in both univariate and multivariate analyses (odds ratio: 1.30; p = 0.005). In men, higher FABP4 level was significantly associated with change in EDSS over time (estimate: 0.0062; p = 0.035). We found no association of FABP4 levels with time to next relapse or a measure of processing speed.

CONCLUSION

FABP4 levels may be associated with increased disability in both men and women with MS independent of effects of BMI and other hormones. Future studies should expand these analyses and further explore downstream mechanisms of adiposity-related effects in MS.

The Leptin Resistance

Leptin is an adipocyte-derived hormone, which contributes to the homeostatic regulation of energy balance and metabolism through humoral and neural pathways. Leptin acts on the neurons in certain brain areas such as the hypothalamus, hippocampus, and brain stem to regulate food intake, thermogenesis, energy expenditure, and homeostasis of glucose/lipid metabolism. The pathologically increased circulating leptin is a biomarker of leptin resistance, which is common in obese individuals. Leptin resistance is defined by a reduced sensitivity or a failure in response of the brain to leptin, showing a decrease in the ability of leptin to suppress appetite or enhance energy expenditure, which causes an increased food intake and finally leads to overweight, obesity, cardiovascular diseases, and other metabolic disorders. Leptin resistance is a challenge for clinical treatment or drug discovery of obesity. Until recently, emerging evidence has been showing novel mechanisms of the leptin resistance. Here, we summarized the advances and controversy of leptin resistance and associated diseases, for better understanding the physiology and pathophysiology of leptin as well as the new strategies for treating obesity and metabolic disorders.

Dietary Interventions and Multiple Sclerosis

Multiple Sclerosis (MS) is a chronic, disabling neurologic disease that has its onset in young adulthood. While the knowledge about underlying pathogenesis of MS has improved significantly over the last few decades, the exact cause still eludes us. Despite the availability of several United States Food and Drug Administration-approved disease-modifying therapies (DMT) for MS in the last two decades, the disease remains disabling for many. DMT use is limited by its partial effectiveness, significant side effects in many cases, and high cost that leads people with MS (PwMS) to look for alternative management options. Dietary intervention as a possible mode to help MS seems very appealing to PwMS; however, scientific data supporting this notion remains sparse. New information on the role of various non-MS health factors, especially vascular disease risk factors such as hypertension, hyperlipidemia, salt intake, and obesity, that may play a role in MS pathogenesis appears very intriguing as it may partly explain the heterogeneity seen in MS activity and disability. This review will highlight the emerging information on various dietary approaches that may affect MS and their possible underlying mechanism.

Leptin sustains spontaneous remyelination in the adult central nervous system

Demyelination is a common feature of many central nervous system (CNS) diseases and is associated with neurological impairment. Demyelinated axons are spontaneously remyelinated depending on oligodendrocyte development, which mainly involves molecules expressed in the CNS environment. In this study, we found that leptin, a peripheral hormone secreted from adipocytes, promoted the proliferation of oligodendrocyte precursor cells (OPCs). Leptin increased the OPC proliferation via in vitro phosphorylation of extracellular signal regulated kinase (ERK); whereas leptin neutralization inhibited OPC proliferation and remyelination in a mouse model of toxin-induced demyelination. The OPC-specific leptin receptor long isoform (LepRb) deletion in mice inhibited both OPC proliferation and remyelination in the response to demyelination. Intrathecal leptin administration increased OPC proliferation. These results demonstrated a novel molecular mechanism by which leptin sustained OPC proliferation and remyelination in a pathological CNS.

Interactions between genetic, lifestyle and environmental risk factors for multiple sclerosis

Genetic predisposition to multiple sclerosis (MS) only explains a fraction of the disease risk; lifestyle and environmental factors are key contributors to the risk of MS. Importantly, these nongenetic factors can influence pathogenetic pathways, and some of them can be modified. Besides established MS-associated risk factors - high latitude, female sex, smoking, low vitamin D levels caused by insufficient sun exposure and/or dietary intake, and Epstein-Barr virus (EBV) infection - strong evidence now supports obesity during adolescence as a factor increasing MS risk. Organic solvents and shift work have also been reported to confer increased risk of the disease, whereas factors such as use of nicotine or alcohol, cytomegalovirus infection and a high coffee consumption are associated with a reduced risk. Certain factors - smoking, EBV infection and obesity - interact with HLA risk genes, pointing at a pathogenetic pathway involving adaptive immunity. All of the described risk factors for MS can influence adaptive and/or innate immunity, which is thought to be the main pathway modulated by MS risk alleles. Unlike genetic risk factors, many environmental and lifestyle factors can be modified, with potential for prevention, particularly for people at the greatest risk, such as relatives of individuals with MS. Here, we review recent data on environmental and lifestyle factors, with a focus on gene-environment interactions.

Glucagon-Like Peptide-1 Analog, Liraglutide, Delays Onset of Experimental Autoimmune Encephalitis in Lewis Rats

Introduction: Recent findings indicate that metabolic disturbances are involved in multiple sclerosis (MS) pathology and influence the susceptibility to treatment, directing attention toward anti-diabetic drugs such as metformin and pioglitazone. Liraglutide, a drug of the glucagon-like peptide-1 (GLP-1) family, is also anti-diabetic and weight-reducing and is, moreover, directly neuroprotective and anti-inflammatory in a broad spectrum of experimental models of brain disease. In this study we investigate the potential for this FDA-approved drug, liraglutide, as a treatment for MS by utilizing the experimental model, experimental autoimmune encephalitis (EAE). Methods: EAE was induced in 30 female Lewis rats that subsequently received twice-daily liraglutide (200 μg/kg s.c.) or saline. Healthy controls were included (saline, n = 6, liraglutide, n = 7). Clinical score and weight were assessed daily by blinded observers. Animals were killed at peak disease severity (day 11) or if exceeding humane endpoint (clinical score ≥4). Protein levels of manganese superoxide dismutase (MnSOD), amyloid precursor protein (APP), and glial fibrillary acidic protein (GFAP) were determined. Results: Liraglutide treatment delayed disease onset (group clinical score significantly >0) by 2 days and markedly reduced disease severity (median clinical score 2 vs. 5; p = 0.0003). Fourteen of 15 (93%) of vehicle-treated rats reached the humane endpoint (clinical score ≥4) by day 11 compared to 5 of 15 (33%) of liraglutide-treated rats (p = 0.0004). Liraglutide substantially increased the mitochondrial antioxidant MnSOD (p < 0.01) and reduced the neurodegenerative marker APP (p = 0.036) in the brain. GFAP levels were not significantly changed with drug treatment (p = 0.09). Conclusion: We demonstrate, for the first time, that liraglutide treatment delays onset of EAE in Lewis rats and is associated with improved protective capacity against oxidative stress. These data suggest GLP-1 receptor agonists should be investigated further as a potential therapy for MS.

Multiple Sclerosis and Obesity: Possible Roles of Adipokines

Multiple Sclerosis (MS) is an autoimmune disorder of the Central Nervous System that has been associated with several environmental factors, such as diet and obesity. The possible link between MS and obesity has become more interesting in recent years since the discovery of the remarkable properties of adipose tissue. Once MS is initiated, obesity can contribute to increased disease severity by negatively influencing disease progress and treatment response, but, also, obesity in early life is highly relevant as a susceptibility factor and causally related risk for late MS development. The aim of this review was to discuss recent evidence about the link between obesity, as a chronic inflammatory state, and the pathogenesis of MS as a chronic autoimmune and inflammatory disease. First, we describe the main cells involved in MS pathogenesis, both from neural tissue and from the immune system, and including a new participant, the adipocyte, focusing on their roles in MS. Second, we concentrate on the role of several adipokines that are able to participate in the mediation of the immune response in MS and on the possible cross talk between the latter. Finally, we explore recent therapy that involves the transplantation of adipocyte precursor cells for the treatment of MS.

Complex relation of HLA-DRB1*1501, age at menarche, and age at multiple sclerosis onset

OBJECTIVE

To examine the relationship between 2 markers of early multiple sclerosis (MS) onset, 1 genetic (HLA-DRB1*1501) and 1 experiential (early menarche), in 2 cohorts.

METHODS

We included 540 white women with MS or clinically isolated syndrome (N = 156 with genetic data available) and 1,390 white women without MS but with a first-degree relative with MS (Genes and Environment in Multiple Sclerosis [GEMS]). Age at menarche, HLA-DRB1*1501 status, and age at MS onset were analyzed.

RESULTS

In both cohorts, participants with at least 1 HLA-DRB1*1501 allele had a later age at menarche than did participants with no risk alleles (MS: mean difference = 0.49, 95% confidence interval [CI] = [0.03-0.95], p = 0.036; GEMS: mean difference = 0.159, 95% CI = [0.012-0.305], p = 0.034). This association remained after we adjusted for body mass index at age 18 (available in GEMS) and for other MS risk alleles, as well as a single nucleotide polymorphism near the HLA-A region previously associated with age of menarche (available in MS cohort). Confirming previously reported associations, in our MS cohort, every year decrease in age at menarche was associated with a 0.65-year earlier MS onset (95% CI = [0.07-1.22], p = 0.027, N = 540). Earlier MS onset was also found in individuals with at least 1 HLA-DRB1*1501 risk allele (mean difference = -3.40 years, 95% CI = [-6.42 to -0.37], p = 0.028, N = 156).

CONCLUSIONS

In 2 cohorts, a genetic marker for earlier MS onset (HLA-DRB1*1501) was inversely related to earlier menarche, an experiential marker for earlier symptom onset. This finding warrants broader investigations into the association between the HLA region and hormonal regulation in determining the onset of autoimmune disease.

Obesity and brain inflammation: a focus on multiple sclerosis

The increase in prevalence of obesity in industrialized societies is an indisputable fact. However, the apparent passive role played by adipocytes, in pathophysiological terms, has been gradually substituted by a metabolically active performance, relevant to many biochemical mechanisms that may contribute to a chronic low-grade inflammatory status, which increasingly imposes itself as a key feature of obesity. This chronic inflammatory status will have to be integrated into the complex equation of many diseases in which inflammation plays a crucial role. Multiple sclerosis (MS) is a chronic inflammatory condition typically confined to the central nervous system, and many work has been produced to find possible points of contact between the biology of this immune-mediated disease and obesity. So far, clinical data are not conclusive, but many biochemical features have been recently disclosed. Brain inflammation has been implicated in some of the mechanisms that lead to obesity, which has also been recognized as an important player in inducing some degree of immune dysfunction. In this review, we collected evidence that allows establishing bridges between obesity and MS. After considering epidemiological controversies, we will focus on possible shared mechanisms, as well as on the potential contributions that disease-modifying drugs may have on this apparent relationship of mutual interference.

The role of cannabinoids and leptin in neurological diseases

Cannabinoids exert a neuroprotective influence on some neurological diseases, including Alzheimer's, Parkinson's, Huntington's, multiple sclerosis and epilepsy. Synthetic cannabinoid receptor agonists/antagonists or compounds can provide symptom relief or control the progression of neurological diseases. However, the molecular mechanism and the effectiveness of these agents in controlling the progression of most of these diseases remain unclear. Cannabinoids may exert effects via a number of mechanisms and interactions with neurotransmitters, neurotropic factors and neuropeptides. Leptin is a peptide hormone involved in the regulation of food intake and energy balance via its actions on specific hypothalamic nuclei. Leptin receptors are widely expressed throughout the brain, especially in the hippocampus, basal ganglia, cortex and cerebellum. Leptin has also shown neuroprotective properties in a number of neurological disorders, such as Parkinson's and Alzheimer's. Therefore, cannabinoid and leptin hold therapeutic potential for neurological diseases. Further elucidation of the molecular mechanisms underlying the effects on these agents may lead to the development of new therapeutic strategies for the treatment of neurological disorders.

Adipokines influence the inflammatory balance in autoimmunity

Over the past few decades, our understanding of the role of adipose tissue has changed dramatically. Far from simply being a site of energy storage or a modulator of the endocrine system, adipose tissue has emerged as an important regulator of multiple important processes including inflammation. Adipokines are a diverse family of soluble mediators with a range of specific actions on the immune response. Autoimmune diseases are perpetuated by chronic inflammatory responses but the exact etiology of these diseases remains elusive. While researchers continue to investigate these causes, millions of people continue to suffer from chronic diseases. To this end, an increased interest has developed in the connection between adipose tissue-secreted proteins that influence inflammation and the onset and perpetuation of autoimmunity. This review will focus on recent advances in adipokine research with specific attention on a subset of adipokines that have been associated with autoimmune diseases.

Negative Regulation of Leptin-induced Reactive Oxygen Species (ROS) Formation by Cannabinoid CB1 Receptor Activation in Hypothalamic Neurons

The adipocyte-derived, anorectic hormone leptin was recently shown to owe part of its regulatory effects on appetite-regulating hypothalamic neuropeptides to the elevation of reactive oxygen species (ROS) levels in arcuate nucleus (ARC) neurons. Leptin is also known to exert a negative regulation on hypothalamic endocannabinoid levels and hence on cannabinoid CB1 receptor activity. Here we investigated the possibility of a negative regulation by CB1 receptors of leptin-mediated ROS formation in the ARC. Through pharmacological and molecular biology experiments we report data showing that leptin-induced ROS accumulation is 1) blunted by arachidonyl-2'-chloroethylamide (ACEA) in a CB1-dependent manner in both the mouse hypothalamic cell line mHypoE-N41 and ARC neuron primary cultures, 2) likewise blocked by a peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist, troglitazone, in a manner inhibited by T0070907, a PPAR-γ antagonist that also inhibited the ACEA effect on leptin, 3) blunted under conditions of increased endocannabinoid tone due to either pharmacological or genetic inhibition of endocannabinoid degradation in mHypoE-N41 and primary ARC neuronal cultures from MAGL(-/-) mice, respectively, and 4) associated with reduction of both PPAR-γ and catalase activity, which are reversed by both ACEA and troglitazone. We conclude that CB1 activation reverses leptin-induced ROS formation and hence possibly some of the ROS-mediated effects of the hormone by preventing PPAR-γ inhibition by leptin, with subsequent increase of catalase activity. This mechanism might underlie in part CB1 orexigenic actions under physiopathological conditions accompanied by elevated hypothalamic endocannabinoid levels.

Endocannabinoid signalling and the deteriorating brain

Ageing is characterized by the progressive impairment of physiological functions and increased risk of developing debilitating disorders, including chronic inflammation and neurodegenerative diseases. These disorders have common molecular mechanisms that can be targeted therapeutically. In the wake of the approval of the first cannabinoid-based drug for the symptomatic treatment of multiple sclerosis, we examine how endocannabinoid (eCB) signalling controls--and is affected by--normal ageing and neuroinflammatory and neurodegenerative disorders. We propose a conceptual framework linking eCB signalling to the control of the cellular and molecular hallmarks of these processes, and categorize the key components of endocannabinoid signalling that may serve as targets for novel therapeutics.

Regulatory T Cells in Obesity

The current concept of the pathogenesis of obesity relates to the inflammation caused by excess of adipose tissue. Regulatory T cells accumulated in visceral adipose tissue (VAT-resident Tregs) are also involved in this pathogenesis. In the present paper the mechanisms responsible for alterations in the number and function of VAT-resident Tregs T in obesity are described. The role of Tregs in inflammation, insulin resistance, atherogenesis, and also the influence on VAT-resident Tregs of adipocytokines and insulin are reviewed.

Higher weight in adolescence and young adulthood is associated with an earlier age at multiple sclerosis onset

BACKGROUND

Growing evidence suggests an association between adolescent obesity and increased risk of multiple sclerosis (MS).

OBJECTIVE

The objective of this paper is to investigate whether weight or body mass index (BMI) in adolescence and young adulthood was associated with age at MS symptom onset.

METHODS

Our cohort is comprised of a sub-group of 184 women enrolled in the New York State MS Consortium registry. Individuals were asked to recall their weight at the time of first menstruation and at age 25. BMI was calculated accordingly for age 25. Regression analyses were carried out to investigate the association between weight or BMI and age at onset.

RESULTS

Weight at menarche was significantly related to younger age at symptom onset (β = -0.073, p = 0.001). These results were also found at age 25 for weight (β = -0.080, p < 0.001) and BMI (β = -0.448, p = 0.001). Significantly earlier disease onset (26.9 years ±9.9) was observed in individuals who were overweight at 25 compared to those who were not overweight (32.1 years ±9.2, p = 0.006).

CONCLUSIONS

Women who reported higher weight in adolescence and BMI in early adulthood were younger at MS onset. Future research should investigate whether there is a causal link between body weight and MS, as prevention lifestyle and dietary interventions could be implemented.

Emerging role of leptin in rheumatoid arthritis

Numerous studies have suggested the importance of leptin against autoimmune diseases such as systemic lupus erythematosus (SLE), multiple sclerosis (MS) and psoriasis. To summarize our current understanding of the role of leptin in inflammatory responses and rheumatoid arthritis (RA), a systematic review was conducted to assess the discrepancy of leptin in RA and its effect on immunity according to different studies. Recently, emerging data have indicated that leptin is involved in the pathological function of RA, which is common in autoimmune disorders. This review discusses the possible consequences of leptin levels in RA. Blocking the key signal pathways of leptin and inhibiting the leptin activity-like leptin antagonist may be a promising way for potential therapeutic treatment of RA at risk of detrimental effects. However, leptin was increased in patients with RA and may also regulate joint damage. Thus, more understanding of the mechanism of leptin in RA would be advantageous in the future.