Blood levels of brain-derived neurotrophic factor (BDNF) in people with multiple sclerosis (MS): A systematic review and meta-analysis

Immediate and short-term effect of physical exercise on BDNF in multiple sclerosis patients: a systematic review and meta-analysis

Low brain-derived neurotrophic factor (BDNF) concentrations have been found in individuals with multiple sclerosis (MS). Physical exercise is an effective strategy for acutely increasing the levels of this neurotrophin in various populations; nevertheless, definitive results are still required for individuals with MS. Thus, this systematic review with meta-analysis aimed to analyze the acute and short-term effects of physical exercise on BDNF concentrations in MS patients. In this pre-registered systematic review (PROSPERO; ID: CRD42024505920), six electronic databases (PubMed-Medline, Scopus, Web of Science, SportDiscus, EbscoHost, and Cochrane) were searched by two independent researchers to identify eligible studies investigating the acute or short-term effects (≤ 3 weeks) of physical exercise sessions on blood concentration of BDNF in MS. Studies that used a sample population with other pathologies or did not provide or specify numerical data on the specified variables were excluded. After applying the inclusion and exclusion criteria, nine studies were included. A total sample of 259 people with MS were analyzed. Effect sizes of outcomes were presented as standardized mean difference (SMD) and 95% confidence intervals (95%CI). The effect estimation was computed using the inverse variance random effects method. Immediately after a session, a significant increase in BDNF was observed (large standardized mean difference (SMD) = 1.52, p = 0.001, I2 = 95). A significant effect (SMD = 0.27, p = 0.05; I2=0%) was found after three weeks of physical training on the BDNF. Our study indicates that physical exercise is an appropriate stimulus to increase BDNF release in MS patients. The acute and short-term increases in this neurotrophin reflect physical exercise's potential and interesting neuroprotective character in populations with neurodegenerative diseases.Trial registration: This study was preregistered in the International Prospective Register of Systematic Review (PROSPERO) with the following registration number: CRD42024505920.

Impact of cognitive-aerobic exercise training on brain-derived neurotrophic factor, dual-tasking abilities, and mood state in individuals with multiple sclerosis

OBJECTIVES

Multiple sclerosis (MS) is a chronic neurological disorder characterized by demyelination and neurodegeneration, leading to various physical, cognitive, and emotional challenges. Dual-task (DT) training, involving performing mental and physical tasks simultaneously, addresses the complex interaction between motor and cognitive functions.

PURPOSE

Given the extensive physical, cognitive, and mood-related issues in this population, this study aimed to examine the effects of combined aerobic-cognitive training (Brythonic) and aerobic training on brain-derived neurotrophic factor (BDNF), DT performance, and mood state in MS patients.

METHODS

Thirty patients (22 women and 8 men) with relapsing-remitting multiple sclerosis (RRMS) and an expanded disability status scale (EDSS) score below four were randomly assigned to three groups: aerobic-cognitive training (Brythonic), aerobic training, and control. The training groups participated in 10 weeks of home-based online training, with two sessions per week. Each session included a 10-minute warmup, 15 to 35 min of exercise, and a 5-minute cool-down. The Brythonic group performed aerobic movements while reciting motivational words, forming a complete positive sentence over ten weeks. The aerobic group performed the same movements without cognitive tasks. Serum BDNF levels, DT performance, and profile of mood states (POMS) were measured before and after the 10-week training period. A two-way ANOVA with repeated measures was used to analyze differences between and within groups, with a significance level of P ≤ 0.05.

RESULTS

BDNF levels significantly increased in the Brythonic group (P = 0.048) and significantly decreased in the control group compared to baseline. In the DT test, the Brythonic group showed significant improvements in the number of correct answers and DT values compared to the aerobic and control groups. The Brythonic group also had a significantly reduced response time compared to the control group. Additionally, selective speed significantly increased in both training groups. In the POMS test, the Brythonic group showed significant improvements in all items except depression compared to the control group. Within the Brythonic group, all items significantly improved from baseline.

CONCLUSION

This study demonstrated that combining motivational words with aerobic movements significantly impacts BDNF levels, DT performance, and mood states. Adding mental exertion to physical activity appears beneficial for patients with MS. Future studies should re-examine these findings with a larger patient cohort.

Brain-Derived Neurotrophic Factor (BDNF) as a Marker of Physical Exercise or Activity Effectiveness in Fatigue, Pain, Depression, and Sleep Disturbances: A Scoping Review

Background/Objectives: Brain-derived neurotrophic factor (BDNF) has been investigated as a potential mechanistic marker or therapeutic target to manage symptoms such as fatigue, pain, depression, and sleep disturbances. However, the variability in BDNF response to exercise or physical activity (exercise/PA) and its clinical relevance in symptom management remains unclear. This scoping review assesses existing studies exploring the relationships between exercise/PA, symptoms, and BDNF levels, specifically focusing on fatigue, pain, depression, and sleep disturbances in adults. Methods: Relevant studies indexed in PubMed and CINAHL were identified. Using systematic review software, two reviewers independently screened and evaluated full texts, based on the following criteria: human studies reporting BDNF levels in adults, using exercise/PA interventions, assessing symptoms (pain, fatigue, depression, and/or sleep disturbance) as outcomes, and published in English. Results: Of 950 records, 35 records met the inclusion criteria. While exercise/PA is broadly supported for managing symptoms, 74.3% (n = 26) of studies reported increased BDNF levels, and only 40% (n = 14) showed significant increases following exercise/PA. Only 14% (n = 5) of studies demonstrated a significant relationship between changes in BDNF and symptoms. No significant differences in BDNF levels and symptoms were observed between different types of exercise (e.g., aerobic vs. strength vs. flexibility/stretching) and PA. Conclusions: The current literature provides insufficient evidence to confirm BDNF as a marker for exercise/PA effectiveness on symptoms. Further clinical investigations are needed to validate its potential as a therapeutic target.

A scoping review of protein biomarkers for schizophrenia: State of progress, underlying biology, and methodological considerations

Schizophrenia is characterized by symptoms such as delusions, hallucinations, and avolition. The diagnosis is clinical, based on interviews and the main treatment involves antipsychotics. Currently, given the lack of clinically applicable biomarkers for schizophrenia, there is no molecular test based on its biological mechanisms to assist psychiatrists either in the prediction or diagnosis of the disorder, nor to measure medication efficacy. This scoping review assessed original articles in English about protein biomarkers for schizophrenia with samples that could be used in a clinical context, classifying them into diagnosis, prognosis, therapeutics, risk for psychosis, and side-effects. The search was conducted on PubMed and key findings were inserted on a summary table. We discussed the methodologies used in these papers, suggested protein panels for validation in longitudinal research, and proposed a hypothesis to explain the observed variability in results. This heterogeneity is explored in light of the debated validity of this construct, applying recent discussions and the disorder's history. Our data suggest that there is insufficient evidence to integrate protein biomarkers into clinical psychiatry for schizophrenia, not due to study quality, but possibly due to flaws in the current diagnostic system. We propose exploring alternative categorization systems.

The Compelling Role of Brain-Derived Neurotrophic Factor Signaling in Multiple Sclerosis: Role of BDNF Activators

Brain-derived neurotrophic factor (BDNF) is a neurotrophin, acting as a neurotrophic signal and neuromodulator in the central nervous system (CNS). BDNF is synthesized from its precursor proBDNF within the CNS and peripheral tissues. Through activation of NTRK2/TRKB (neurotrophic receptor tyrosine kinase 2), BDNF promotes neuronal survival, synaptic plasticity, and neuronal growth, whereas it inhibits microglial activation and the release of pro-inflammatory cytokines. BDNF is dysregulated in different neurodegenerative diseases and depressions. However, there is a major controversy concerning BDNF levels in the different stages of multiple sclerosis (MS). Therefore, this review discusses the potential role of BDNF signaling in stages of MS, and how BDNF modulators affect the pathogenesis and outcomes of this disease.

The link between BDNF and platelets in neurological disorders

Platelets are considered one of the most important reservoirs not only of growth factors, but also of neurotrophic factors that could contribute to the repair of vascular lesions and the prevention of neurological deterioration. Among these factors, Brain-Derived Neurotrophic Factor (BDNF) - a protein belonging to the neurotrophin family - is widely expressed both in the hippocampus and in platelets. Platelets constitute an important reservoir of BDNF; however, little is known about the factors modulating its release into the circulation and whether anti-platelet drugs affect this secretion. In this review, we have discussed the link between BDNF and platelets and their role in neurological disorders.

Serum miR-34a-5p, miR-103a-3p, and miR-376a-3p as possible biomarkers of conversion from relapsing-remitting to secondary progressive multiple sclerosis

Relapsing-remitting (RR) Multiple Sclerosis (MS) is the most common form of the disease; RRMS patients can maintain their clinical phenotype throughout life or can develop a secondary progressive (SP) course over time. We investigated whether circulating miRNAs can predict RR-to-SPMS conversion. A serum miRNAs profile was initially analyzed in a cross-sectional study by qPCR in 16 patients (8 RRMS and 8 SPMS) (Discovery cohort). Three miRNAs, i.e. miR-34a-5p, miR-103a-3p and miR-376a-3p, were significantly up-regulated in SPMS compared to RRMS patients (p < 0.0 5). Serum concentration of the same miRNAs was subsequently analyzed in a retrospective study by ddPCR at baseline in 69 RRMS patients who did (N = 36 cSPMS) or did not (N = 33) convert into SPMS over a 10-year observation period (Study cohort). The results showed that these miRNAs were significantly increased at baseline only in those RRMS patients who converted to SPMS over time. miR-34a-5p and miR-376a-3p alone were significantly increased in cSPMS sera at the end of the 10-years period too. Serum concentration of miR-34a-5p, miR-103a-3p and miR-376a-3p is increased in RRMS patients several years before their conversion to SPMS. These miRNAs might be useful biomarkers to predict the conversion from RRMS to SPMS.

MIND Diet Impact on Multiple Sclerosis Patients: Biochemical Changes after Nutritional Intervention

There is substantial evidence supporting the neuroprotective effects of the MIND diet in neurodegenerative diseases like Parkinson's and Alzheimer's. Our aim was to evaluate the impact of a nutritional intervention (NI) with this diet on multiple sclerosis (MS) patients. The study was conducted in two stages. In the first stage, two groups were included: MS patients before the NI (group A) and healthy control subjects (group B). In this stage, groups (A) and (B) were compared (case-control study). In the second stage, group (A) was assessed after the NI, with comparisons made between baseline and final measurements (before-and-after study). In the case-control stage (baseline evaluation), we found significant differences in fatigue scores (p < 0.001), adherence to the MIND diet (p < 0.001), the serum levels of brain-derived neurotrophic factor (BDNF) (p < 0.001), and higher oxidative status in the MS group, with lower levels of reduced glutathione (p < 0.001), reduced/oxidised glutathione ratio (p < 0.001), and elevated levels of lipoperoxidation (p < 0.002) and 8-hydroxy-2'-deoxyguanosine (p < 0.025). The before-and-after intervention stage showed improvements in fatigue scores (p < 0.001) and physical quality-of-life scores (MSQOL-54) (p < 0.022), along with decreases in the serum levels of glial-derived neurotrophic factor (GDNF) (p < 0.041), lipoperoxidation (p < 0.046), and 8-hydroxy-2'-deoxyguanosine (p < 0.05). Consumption of the MIND diet is linked to clinical and biochemical improvement in MS patients.

The Use of Neurotrophic Factors as a Promising Strategy for the Treatment of Neurodegenerative Diseases (Review)

The review considers the use of exogenous neurotrophic factors in the treatment of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, and others. This group of diseases is associated with the death of neurons and dysfunction of the nervous tissue. Currently, there is no effective therapy for neurodegenerative diseases, and their treatment remains a serious problem of modern medicine. A promising strategy is the use of exogenous neurotrophic factors. Targeted delivery of these factors to the nervous tissue can improve survival of neurons during the development of neurodegenerative processes and ensure neuroplasticity. There are methods of direct injection of neurotrophic factors into the nervous tissue, delivery using viral vectors, as well as the use of gene cell products. The effectiveness of these approaches has been studied in numerous experimental works and in a number of clinical trials. Further research in this area could provide the basis for the creation of an alternative treatment for neurodegenerative diseases.

Plasmodium knowlesi infection is associated with elevated circulating biomarkers of brain injury and endothelial activation

Introduction

Malaria remains a major public health concern with substantial morbidity and mortality worldwide. In Malaysia, the emergence of Plasmodium knowlesi has led to a surge in zoonotic malaria cases and deaths in recent years. Signs of cerebral involvement have been observed in a non-comatose, fatal case of severe knowlesi infection, but the potential impact of this malaria species on the brain remains underexplored. To address this gap, we investigated circulating levels of brain injury, inflammation, and vascular biomarkers in a cohort of knowlesi-infected patients and controls.

Methods

Archived plasma samples from 19 patients with confirmed symptomatic knowlesi infection and 19 healthy, age-matched controls from Peninsular Malaysia were analysed. A total of 52 plasma biomarkers of brain injury, inflammation, and vascular activation were measured using Luminex and SIMOA assays. Wilcoxon tests were used to examine group differences, and biomarker profiles were explored through hierarchical clustering heatmap analysis.

Results

Bonferroni-corrected analyses revealed significantly elevated brain injury biomarker levels in knowlesi-infected patients, including S100B (p<0.0001), Tau (p=0.0007), UCH-L1 (p<0.0001), αSyn (p<0.0001), Park7 (p=0.0006), NRGN (p=0.0022), and TDP-43 (p=0.005). Compared to controls, levels were lower in the infected group for BDNF (p<0.0001), CaBD (p<0.0001), CNTN1 (p<0.0001), NCAM-1 (p<0.0001), GFAP (p=0.0013), and KLK6 (p=0.0126). Hierarchical clustering revealed distinct group profiles for circulating levels of brain injury and vascular activation biomarkers.

Conclusions

Our findings highlight for the first time the impact of Plasmodium knowlesi infection on the brain, with distinct alterations in cerebral injury and endothelial activation biomarker profiles compared to healthy controls. Further studies are warranted to investigate the pathophysiology and clinical significance of these altered surrogate markers, through both neuroimaging and long-term neurocognitive assessments.

Identification and management of subclinical disease activity in early multiple sclerosis: a review

IMPORTANCE

Early treatment initiation in multiple sclerosis (MS) is crucial in preventing irreversible neurological damage and disability progression. The current assessment of disease activity relies on relapse rates and magnetic resonance imaging (MRI) lesion activity, but inclusion of other early, often "hidden," indicators of disease activity may describe a more comprehensive picture of MS.

OBSERVATIONS

Early indicators of MS disease activity other than relapses and MRI activity, such as cognitive impairment, brain atrophy, and fatigue, are not typically captured by routine disease monitoring. Furthermore, silent progression (neurological decline not clearly captured by standard methods) may occur undetected by relapse and MRI lesion activity monitoring. Consequently, patients considered to have no disease activity actually may have worsening disease, suggesting a need to revise MS management strategies with respect to timely initiation and escalation of disease-modifying therapy (DMT). Traditionally, first-line MS treatment starts with low- or moderate-efficacy therapies, before escalating to high-efficacy therapies (HETs) after evidence of breakthrough disease activity. However, multiple observational studies have shown that early initiation of HETs can prevent or reduce disability progression. Ongoing randomized clinical trials are comparing escalation and early HET approaches.

CONCLUSIONS AND RELEVANCE

There is an urgent need to reassess how MS disease activity and worsening are measured. A greater awareness of "hidden" indicators, potentially combined with biomarkers to reveal silent disease activity and neurodegeneration underlying MS, would provide a more complete picture of MS and allow for timely therapeutic intervention with HET or switching DMTs to address suboptimal treatment responses.

Blood and CSF levels of brain-derived neurotrophic factor in patients with encephalopathy/encephalitis: a systematic review and meta-analysis

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is critical for enhancing the survival and growth of neurons and modulating the synaptic plasticity. BDNF levels have been demonstrated to be changed in plasma and cerebrospinal fluid (CSF) following brain insults such as inflammation or ischemia or infection in several studies. Currently, there is no systematic review regarding BDNF levels in encephalitis or encephalopathy patients. Considering inconsistency between studies, we aimed to pool the data from existing studies to determine whether blood or CSF levels of BDNF are different in patients with encephalopathy/encephalitis.

METHODS

We comprehensively searched Web of Science, PubMed, Scopus, and Embase databases to identify eligible studies. The last search occurred in December 2022.

RESULTS

12 studies met our inclusion criteria and ten studies including 283 patients and 323 healthy controls were enrolled in this meta-analysis. In comparison to controls, patients with encephalitis/encephalopathy had higher levels of BDNF in their CSF [standardized mean difference (SMD) = 1.48, 95% CI 0.18-2.77; P = 0.03)], while their blood levels of BDNF did not differ significantly [standardized mean difference (SMD) = 0.27, 95% CI = - 0.71 to 1.25; P = 0.58)]. Moreover, regarding the heterogeneity among studies reporting BDNF blood levels, we performed two subgroup analyses based on the disease etiology and the specimen (plasma and serum); none of them indicated statistically significant difference in BDNF levels between the subgroups (P = 0.41 and 0.20, respectively).

CONCLUSION

Meta-analysis provides evidence that patients with encephalopathy/encephalitis have higher CSF levels of BDNF compared to controls.

Risk of MS relapse and deterioration after COVID-19: A systematic review and meta-analysis

BACKGROUND

Upper respiratory viral infections have long been considered triggers for multiple sclerosis (MS) relapse and exacerbation. The possible effects of SARS-CoV-2 infection on MS relapse and deterioration remain controversial.

METHODS

We systematically searched PubMed, Scopus, Embase, Cochrane, and Web of Science databases to find relevant studies assessing changes in relapse rates or Expanded Disability Status Scale (EDSS) following COVID-19 in people with MS. Meta-analyses were performed, and to investigate sources of heterogeneity, subgroup analysis, meta-regression, and sensitivity analysis were conducted.

RESULTS

We included 14 studies in our systematic review and meta-analysis. The meta-analysis demonstrated that COVID-19 was not associated with a rise in relapse rate (risk ratio (RR): 0.97, 95 % confidence interval (CI): 0.67, 1.41, p-value: 0.87) or a rise in EDSS (standardized mean difference (SMD): -0.09, 95 % CI: -0.22, 0.03, p-value: 0.13). The analysis of EDSS changes indicated a significant heterogeneity (I2: 55 %, p-value: 0.01). Other analyses were not statistically significant.

CONCLUSIONS

COVID-19 infection was not associated with an increased risk of relapse and clinical deterioration in people with MS.

Role of fenofibrate in multiple sclerosis

Multiple sclerosis (MS) is the most frequent inflammatory and demyelinating disease of the central nervous system (CNS). The underlying pathophysiology of MS is the destruction of myelin sheath by immune cells. The formation of myelin plaques, inflammation, and injury of neuronal myelin sheath characterizes its neuropathology. MS plaques are multiple focal regions of demyelination disseminated in the brain's white matter, spinal cords, deep grey matter, and cerebral cortex. Fenofibrate is a peroxisome proliferative activated receptor alpha (PPAR-α) that attenuates the inflammatory reactions in MS. Fenofibrate inhibits differentiation of Th17 by inhibiting the expression of pro-inflammatory signaling. According to these findings, this review intended to illuminate the mechanistic immunoinflammatory role of fenofibrate in mitigating MS neuropathology. In conclusion, fenofibrate can attenuate MS neuropathology by modulating different pathways, including oxidative stress, autophagy, mitochondrial dysfunction, inflammatory-signaling pathways, and neuroinflammation.

Effectiveness of high-intensity interval training on peripheral brain-derived neurotrophic factor in adults: A systematic review and network meta-analysis

BACKGROUND

High-intensity interval training (HIIT) has emerged as an alternative training method to increase brain-derived neurotrophic factor (BDNF) levels, a crucial molecule involved in plastic brain changes. Its effect compared to moderate-intensity continuous training (MICT) is controversial. We aimed to estimate, and to comparatively evaluate, the acute and chronic effects on peripheral BDNF levels after a HIIT, MICT intervention or a control condition in adults.

METHODS

The CINAHL, Cochrane, PubMed, PEDro, Scopus, SPORTDiscus, and Web of Science databases were searched for randomized controlled trials (RCTs) from inception to June 30, 2023. A network meta-analysis was performed to assess the acute and chronic effects of HIIT versus control condition, HIIT versus MICT and MICT versus control condition on BDNF levels. Pooled standardized mean differences (SMDs) and their 95% confidence intervals (95% CIs) were calculated for RCTs using a random-effects model.

RESULTS

A total of 22 RCTs were selected for the systematic review, with 656 participants (aged 20.4-79 years, 34.0% females) and 20 were selected for the network meta-analysis. Network SMD estimates were significant for HIIT versus control condition (1.49, 95% CI: 0.61, 2.38) and MICT versus control condition (1.08, 95% CI: 0.04, 2.12) for acutely BDNF increase. However, pairwise comparisons only resulted in a significant effect for HIIT versus control condition.

CONCLUSIONS

HIIT is the best training modality for acutely increasing peripheral BDNF levels in adults. HIIT may effectively increase BDNF levels in the long term.

Exploring the mRNA and Plasma Protein Levels of BDNF, NT4, SIRT1, HSP27, and HSP70 in Multiple Sclerosis Patients and Healthy Controls

Multiple sclerosis (MS) is a chronic, autoimmune neurodegenerative disease affecting the central nervous system. It is a major cause of non-traumatic neurological disability among young adults in North America and Europe. This study focuses on neuroprotective genes (BDNF, NT4/5, SIRT1, HSP70, and HSP27). Gene expression and protein levels of these markers were compared between MS patients and healthy controls. Blood samples were collected from 42 patients with multiple sclerosis (MS) and 48 control subjects without MS. Quantitative real-time PCR was performed to measure the expression of specific genes. The samples were analyzed in duplicate, and the abundance of mRNA was quantified using the 2-ΔCt method. ELISA assay was used to measure the concentration of specific proteins in the plasma samples. The results show that a 3.5-fold decrease in the gene expression of BDNF corresponds to a 1.5-fold downregulation in the associated plasma protein concentration (p < 0.001). Similar trends were observed with NT-4 (five-fold decrease, slight elevation in protein), SIRT1 (two-fold decrease, two-fold protein decrease), HSP70 (four-fold increase, nearly two-fold protein increase), and HSP27 (four-fold increase, two-fold protein increase) (p < 0.001). This study reveals strong correlations between gene expression and protein concentration in MS patients, emphasizing the relevance of these neuroprotective markers in the disease.

Efficacy of remote exercise and physiotherapy programs on depressive symptoms in people with multiple sclerosis - A systematic review and meta-analysis

BACKGROUND

The prevalence of depression in Multiple Sclerosis (MS) is common and negatively affects the quality of life of patients. The studies of the effect of remote forms of treatment conclude that it is a fairly easy process to carry out and with very good results for patients. Thus, the purpose of this systematic review and meta-analysis is to investigate randomized controlled trials on the effectiveness of remote forms of exercise and physiotherapy on the depressive symptoms of people with MS.

METHODS

A literature search was conducted in PubMed, Scopus, PsychInfo, SportDiscus, Web of Science and ResearchGate databases. The keywords for the search were: telerehabilitation, telecounseling, tele, telephone, physiotherapy, physical therapy, rehabilitation, therapeutic exercise, exercise, depression, depressive disorders, multiple sclerosis and MS. In addition, some inclusion and exclusion criteria were defined for the selection of the final studies, which were also evaluated with the PEDro scale for their quality.

RESULTS

Among the initial 176 studies found, 6 were included in the systematic review. The development of a remote individualized exercise program based on assessment, personal goals and daily life of the patient, as well as a program based on motor imagery training, showed beneficial effects on depression in people with MS, which are considered possibly equivalent to those of in-person intervention. Μeta-analysis revealed that remote exercise and physiotherapy programs are significantly more effective than control group interventions for the management of depression in people with MS (random effects model, Hedges' g = -0.41, 95%CI = -0.74,-0.09, SE = 0.17, p = 0.01). The sub-group analysis showed that studies that had chosen not to have their control group carry out any form of intervention had more significant outcomes than the others.

CONCLUSION

Through telephone communication or other electronic monitoring systems, can be achieved an effective treatment of people with depression and MS, based on exercise and physiotherapy. However, more studies are deemed necessary to find the most appropriately designed and therapeutic forms of remote intervention.

Pathogenic Role of Fibrinogen in the Neuropathology of Multiple Sclerosis: A Tale of Sorrows and Fears

Multiple sclerosis (MS) is an autoimmune demyelinating neurodegenerative disease of the central nervous system (CNS) due to injury of the myelin sheath by immune cells. The clotting factor fibrinogen is involved in the pathogenesis of MS by triggering microglia and the progress of neuroinflammation. Fibrinogen level is correlated with MS severity; consequently, inhibition of the fibrinogen cascade may reduce MS neuropathology. Thus, this review aimed to clarify the potential role of fibrinogen in the pathogenesis of MS and how targeting of fibrinogen affects MS neuropathology. Accumulation of fibrinogen in the CNS may occur independently or due to disruption of blood-brain barrier (BBB) integrity in MS. Fibrinogen acts as transduction and increases microglia activation which induces the progression of inflammation, oxidative stress, and neuronal injury. Besides, brain fibrinogen impairs the remyelination process by inhibiting the differentiation of oligodendrocyte precursor cells. These findings proposed that fibrinogen is associated with MS neuropathology through interruption of BBB integrity, induction of neuroinflammation, and demyelination with inhibition of the remyelination process by suppressing oligodendrocytes. Therefore, targeting of fibrinogen and/or CD11b/CD18 receptors by metformin and statins might decrease MS neuropathology. In conclusion, inhibiting the expression of CD11b/CD18 receptors by metformin and statins may decrease the pro-inflammatory effect of fibrinogen on microglia which is involved in the progression of MS.

The potential therapeutic effect of statins in multiple sclerosis: beneficial or detrimental effects

Multiple sclerosis (MS) is a chronic progressive disabling disease of the central nervous system (CNS) characterized by demyelination and neuronal injury. Dyslipidemia is observed as one of the imperative risk factors involved in MS neuropathology. Also, chronic inflammation in MS predisposes to the progress of dyslipidemia. Therefore, treatment of dyslipidemia in MS by statins may attenuate dyslipidemia-induced MS and avert MS-induced metabolic changes. Therefore, the present review aimed to elucidate the possible effects of statins on the pathogenesis and outcomes of MS. Statins adversely affect the cognitive function in MS by decreasing brain cholesterol CoQ10, which is necessary for the regulation of neuronal mitochondrial function. However, statins could be beneficial in MS by shifting the immune response from pro-inflammatory Th17 to an anti-inflammatory regulatory T cell (Treg). The protective effect of statins against MS is related to anti-inflammatory and immunomodulatory effects with modulation of fibrinogen and growth factors. In conclusion, the effects of statins on MS neuropathology seem to be conflicting, as statins seem to be protective in the acute phase of MS through anti-inflammatory and antioxidant effects. However, statins lead to detrimental effects in the chronic phase of MS by reducing brain cholesterol and inhibiting the remyelination process.

Emerging imaging and liquid biomarkers in multiple sclerosis

The advent of highly effective disease modifying therapy has transformed the landscape of multiple sclerosis (MS) care over the last two decades. However, there remains a critical, unmet need for sensitive and specific biomarkers to aid in diagnosis, prognosis, treatment monitoring, and the development of new interventions, particularly for people with progressive disease. This review evaluates the current data for several emerging imaging and liquid biomarkers in people with MS. MRI findings such as the central vein sign and paramagnetic rim lesions may improve MS diagnostic accuracy and evaluation of therapy efficacy in progressive disease. Serum and cerebrospinal fluid levels of several neuroglial proteins, such as neurofilament light chain and glial fibrillary acidic protein, show potential to be sensitive biomarkers of pathologic processes such as neuro-axonal injury or glial-inflammation. Additional promising biomarkers, including optical coherence tomography, cytokines and chemokines, microRNAs, and extracellular vesicles/exosomes, are also reviewed, among others. Beyond their potential integration into MS clinical care and interventional trials, several of these biomarkers may be informative of MS pathogenesis and help elucidate novel targets for treatment strategies.

Blood levels of brain-derived neurotrophic factor (BDNF) in systemic lupus erythematous (SLE): a systematic review and meta-analysis

OBJECTIVES

BDNF has been implicated in the pathophysiology of systemic lupus erythematosus (SLE), especially its neuropsychiatric symptoms. The purpose of this study was to investigate the profile of blood BDNF levels in patients with SLE.

METHODS

We searched PubMed, EMBASE, and the Cochrane Library for papers that compared BDNF levels in SLE patients and healthy controls (HCs). The Newcastle-Ottawa scale was used to assess the quality of the included publications, and statistical analyses were carried out using R 4.0.4.

RESULTS

The final analysis included eight studies totaling 323 healthy controls and 658 SLE patients. Meta-analysis did not show statistically significant differences in blood BDNF concentrations in SLE patients compared to HCs (SMD 0.08, 95% CI [ - 1.15; 1.32], P value = 0.89). After removing outliers, there was no significant change in the results: SMD -0.3868 (95% CI [ - 1.17; 0.39], P value = 0.33. Univariate meta-regression analysis revealed that sample size, number of males, NOS score, and mean age of the SLE participants accounted for the heterogeneity of the studies (R2 were 26.89%, 16.53%, 18.8%, and 49.96%, respectively).

CONCLUSION

In conclusion, our meta-analysis found no significant association between blood BDNF levels and SLE. The potential role and relevance of BDNF in SLE need to be further examined in higher quality studies.

Recent advances on the molecular mechanisms of exercise-induced improvements of cognitive dysfunction

Physical exercise is of great significance for maintaining human health. Exercise can provide varying degrees of benefits to cognitive function at all stages of life cycle. Currently, with the aging of the world's population and increase of life expectancy, cognitive dysfunction has gradually become a disease of high incidence, which is accompanied by neurodegenerative diseases in elderly individuals. Patients often exhibit memory loss, aphasia and weakening of orientation once diagnosed, and are unable to have a normal life. Cognitive dysfunction largely affects the physical and mental health, reduces the quality of life, and causes a great economic burden to the society. At present, most of the interventions are aimed to maintain the current cognitive level and delay deterioration of cognition. In contrast, exercise as a nonpharmacological therapy has great advantages in its nontoxicity, low cost and universal application. The molecular mechanisms underlying the effect of exercise on cognition are complex, and studies have been extensively centered on neural plasticity, the direct target of exercise in the brain. In addition, mitochondrial stability and energy metabolism are essential for brain status. Meanwhile, the organ-brain axis responds to exercise and induces release of cytokines related to cognition. In this review, we summarize the latest evidence on the molecular mechanisms underlying the effects of exercise on cognition, and point out directions for future research.

Neurotrophic Factors as Regenerative Therapy for Neurodegenerative Diseases: Current Status, Challenges and Future Perspectives

Neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), multiple sclerosis (MS), spinal cord injury (SCI), and amyotrophic lateral sclerosis (ALS), are characterized by acute or chronic progressive loss of one or several neuronal subtypes. However, despite their increasing prevalence, little progress has been made in successfully treating these diseases. Research has recently focused on neurotrophic factors (NTFs) as potential regenerative therapy for neurodegenerative diseases. Here, we discuss the current state of knowledge, challenges, and future perspectives of NTFs with a direct regenerative effect in chronic inflammatory and degenerative disorders. Various systems for delivery of NTFs, such as stem and immune cells, viral vectors, and biomaterials, have been applied to deliver exogenous NTFs to the central nervous system, with promising results. The challenges that currently need to be overcome include the amount of NTFs delivered, the invasiveness of the delivery route, the blood-brain barrier permeability, and the occurrence of side effects. Nevertheless, it is important to continue research and develop standards for clinical applications. In addition to the use of single NTFs, the complexity of chronic inflammatory and degenerative diseases may require combination therapies targeting multiple pathways or other possibilities using smaller molecules, such as NTF mimetics, for effective treatment.

Serum and cerebrospinal fluid BDNF concentrations are associated with neurological and cognitive improvement in multiple sclerosis: A pilot study

BACKGROUND

Biomarkers of disease activity have been intensively studied in multiple sclerosis (MS) but knowledge on predictors of disability improvement is limited. The aim of this pilot study was to explore whether increased brain-derived neurotrophic factor concentrations in serum and CSF (sBDNF/cBDNF) precede neurological and cognitive improvement in MS.

METHODS

In this pilot, monocentric prospective cohort study we collected serum/CSF samples at baseline together with EDSS (n = 36) and cognitive testing (n = 34) in patients with relapsing-remitting/primary progressive MS or clinically isolated syndrome. BDNF was assessed in serum and CSF with a single molecule array (SIMOA) HD-1 analyser (Quanterix). Twelve months later EDSS and cognitive testing were repeated. BDNF concentrations of patients with vs. without disability or cognitive improvement (disability improvement: decrease in EDSS ≥ 0.5; cognitive improvement: average z-score increase in neuropsychological performance ≥ 0.5) were compared using univariate ANOVAs adjusting for covariates.

RESULTS

Compared to subjects without, patients with disability improvement had higher sBDNF at baseline (q = 0.04). Subjects with cognitive improvement had higher cBDNF at baseline than those without cognitive improvement (q = 0.004). Secondary analysis demonstrated significant correlations between sBDNF and EDSS change (q = 0.036), cBDNF and average z-score change (q = 0.04) and cBDNF and number of cognitive tests with improvement (q = 0.04), while controlling for covariates.

CONCLUSIONS

Our findings suggest a possible role for BDNF in neurological and cognitive improvement in MS. These findings have to be confirmed in a larger sample but they already highlight the potential of BDNF as a biomarker for disability improvement and neuroplasticity in MS.

The Role of Brain-Derived Neurotrophic Factor in Immune-Related Diseases: A Narrative Review

Brain-derived neurotrophic factor (BDNF) is a neurotrophin regulating synaptic plasticity, neuronal excitability, and nociception. It seems to be one of the key molecules in interactions between the central nervous system and immune-related diseases, i.e., diseases with an inflammatory background of unknown etiology, such as inflammatory bowel diseases or rheumatoid arthritis. Studies show that BDNF levels might change in the tissues and serum of patients during the course of these conditions, e.g., affecting cell survival and modulating pain severity and signaling pathways involving different neurotransmitters. Immune-related conditions often feature psychiatric comorbidities, such as sleep disorders (e.g., insomnia) and symptoms of depression/anxiety; BDNF may be related as well to them as it seems to exert an influence on sleep structure; studies also show that patients with psychiatric disorders have decreased BDNF levels, which increase after treatment. BDNF also has a vital role in nociception, particularly in chronic pain, hyperalgesia, and allodynia, participating in the formation of central hypersensitization. In this review, we summarize the current knowledge on BDNF's function in immune-related diseases, sleep, and pain. We also discuss how BDNF is affected by treatment and what consequences these changes might have beyond the nervous system.