Preventive exercise attenuates IL-2-driven mood disorders in multiple sclerosis

Physical exercise and synaptic protection in human and pre-clinical models of multiple sclerosis

In multiple sclerosis, only immunomodulatory and immunosuppressive drugs are recognized as disease-modifying therapies. However, in recent years, several data from pre-clinical and clinical studies suggested a possible role of physical exercise as disease-modifying therapy in multiple sclerosis. Current evidence is sparse and often conflicting, and the mechanisms underlying the neuroprotective and antinflammatory role of exercise in multiple sclerosis have not been fully elucidated. Data, mainly derived from pre-clinical studies, suggest that exercise could enhance long-term potentiation and thus neuroplasticity, could reduce neuroinflammation and synaptopathy, and dampen astrogliosis and microgliosis. In humans, most trials focused on direct clinical and MRI outcomes, as investigating synaptic, neuroinflammatory, and pathological changes is not straightforward compared to animal models. The present review analyzed current evidence and limitations in research concerning the potential disease-modifying therapy effects of exercise in multiple sclerosis in animal models and human studies.

Inflammation and Connexin 43 profiles in the prefrontal cortex are relevant to stress susceptibility and resilience in mice

Depression is a major chronic mental illness worldwide, characterized by anhedonia and pessimism. Exposed to the same stressful stimuli, some people behave normally, while others exhibit negative behaviors and psychology. The exact molecular mechanisms linking stress-induced depressive susceptibility and resilience remain unclear. Connexin 43 (Cx43) forms gap junction channels between the astrocytes, acting as a crucial role in the pathogenesis of depression. Cx43 dysfunction could lead to depressive behaviors, and depression down-regulates the expression of Cx43 in the prefrontal cortex (PFC). Besides, accumulating evidence indicates that inflammation is one of the most common pathological features of the central nervous system dysfunction. However, the roles of Cx43 and peripheral inflammation in stress-susceptible and stress-resilient individuals have rarely been investigated. Thus, animals were classified into the chronic unpredictable stress (CUS)-susceptible group and the CUS-resilient group based on the performance of behavioral tests following the CUS protocol in this study. The protein expression of Cx43 in the PFC, the Cx43 functional changes in the PFC, and the expression levels including interleukin (IL)-1β, tumor necrosis factor-α, IL-6, IL-2, IL-10, and IL-18 in the peripheral serum were detected. Here, we found that stress exposure triggered a significant reduction in Cx43 protein expression in the CUS-susceptible mice but not in the CUS-resilient mice accompanied by various Cx43 phosphorylation expression and the changes of inflammatory signals. Stress resilience is associated with Cx43 in the PFC and fluctuation in inflammatory signaling, showing that therapeutic targeting of these pathways might promote stress resilience.

Association between peripheral plasma cytokine levels and suicidal ideation in first-episode, drug-naïve major depressive disorder

BACKGROUND

Inflammatory processes could potentially impact both mood and suicide risk, however, the relationship between cytokines and suicidal ideation remains unclear. This study aimed to investigate the association between plasma levels of cytokines and suicidal ideation in population with major depressive disorders (MDD).

METHODS

A cross-sectional study was performed to assess the peripheral plasma levels of interleukin-1β (IL-1β), IL-2, IL-6, IL-8, IL-10 and tumor necrosis factor-α (TNF-α) in 88 Chinese Han first-episode drug-naïve MDD patients. Suicidal ideation in the past week were identified using the Beck Scale for Suicide Ideation-Chinese Version (BSI-CV). The Hamilton Depression Rating Scale-17 (HAMD-17), the Hamilton Anxiety Rating Scale-14 (HAMA-14) and the Childhood Trauma Questionnaire (CTQ) was used to assess depression, anxiety and childhood trauma. Multivariable logistic regression models were used to estimate the association between cytokines and suicidal ideation. Interaction and stratified analyses were conducted according to age, sex, marital status, education, smoking status, BMI and physical activity.

RESULTS

Among the 88 participants, 42 individuals (47.7%) reported suicidal ideation within the past week. In the fully adjusted model, a statistically significant trend was observed in the association between IL-2 level and suicidal ideation (OR: 1.40, 95% CI: 1.00-1.97). The stratified analysis showed a statistically significant association between IL-6 level and suicidal ideation among younger people (OR: 1.17, 95% CI: 1.01-1.36) and a significant positive association between IL-8 (OR: 1.59, 95% CI: 1.03-2.44) and IL-10 (OR: 2.51, 95% CI: 1.27-4.96) levels and suicide ideation among higher educated populations.

LIMITATIONS

The cross-sectional design, residual confounding effects and small sample size CONCLUSION: Our findings indicate a significant positive association between plasma IL-2 level and suicidal ideation in MDD patients. IL-2 has the potential to be a biomarker of suicidal ideation in patients with depression.

Roflumilast: Modulating neuroinflammation and improving motor function and depressive symptoms in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is an autoimmune disease causing central nervous system demyelination, often associated with depression. Current treatments for MS do not effectively address both physical disability and depression. Roflumilast, a phosphodiesterase-4 inhibitor with anti-inflammatory properties, has shown promise for autoimmune diseases.

METHODS

We used an experimental autoimmune encephalomyelitis (EAE) rat model to study roflumilast's effects. Motor dysfunction and depression symptoms were assessed, and histopathological analysis evaluated its anti-inflammatory properties. Flow cytometry examined the drug's impact on brain microglia. TNF-α, IL-1β, and IL-6 levels in hippocampal tissue were assessed using ELISA kits.

RESULTS

Roflumilast improved motor dysfunction and depression symptoms in EAE rats. Histopathological analysis revealed reduced inflammation, demyelination, and axonal loss in the spinal cord. Roflumilast suppressed microglial cell activation and conversion to pro-inflammatory M1-type cells. Flow cytometry showed roflumilast inhibited inflammatory marker expression in microglia and their activation in the hippocampus. IL-6 was identified as a roflumilast target for suppressing hippocampal inflammation.

LIMITATIONS

This study used an animal model and did not assess long-term or potential side effects of roflumilast treatment.

CONCLUSIONS

Roflumilast holds promise as a treatment for depression and motor impairment in MS. Its anti-inflammatory properties, reducing inflammation and inhibiting microglial activation, suggest its potential for MS therapy. However, further research is needed to evaluate long-term effects and safety in MS patients.

Preventive exercise and physical rehabilitation promote long-term potentiation-like plasticity expression in patients with multiple sclerosis

BACKGROUND AND PURPOSE

Loss of long-term potentiation (LTP) expression has been associated with a worse disease course in relapsing-remitting multiple sclerosis (RR-MS) and represents a pathophysiological hallmark of progressive multiple sclerosis (PMS). Exercise and physical rehabilitation are the most prominent therapeutic approaches to promote synaptic plasticity. We aimed to explore whether physical exercise is able to improve the expression of LTP-like plasticity in patients with multiple sclerosis (MS).

METHODS

In 46 newly diagnosed RR-MS patients, we explored the impact of preventive exercise on LTP-like plasticity as assessed by intermittent theta-burst stimulation. Patients were divided into sedentary or active, based on physical activity performed during the 6 months prior to diagnosis. Furthermore, in 18 patients with PMS, we evaluated the impact of an 8-week inpatient neurorehabilitation program on clinical scores and LTP-like plasticity explored using paired associative stimulation (PAS). Synaptic plasticity expression was compared in patients and healthy subjects.

RESULTS

Reduced LTP expression was found in RR-MS patients compared with controls. Exercising RR-MS patients showed a greater amount of LTP expression compared with sedentary patients. In PMS patients, LTP expression was reduced compared with controls and increased after 8 weeks of rehabilitation. In this group of patients, LTP magnitude at baseline predicted the improvement in hand dexterity.

CONCLUSIONS

Both preventive exercise and physical rehabilitation may enhance the expression of LTP-like synaptic plasticity in MS, with potential beneficial effects on disability accumulation.

The Role of Selected Interleukins in the Development and Progression of Multiple Sclerosis-A Systematic Review

Multiple sclerosis is a disabling inflammatory disorder of the central nervous system characterized by demyelination and neurodegeneration. Given that multiple sclerosis remains an incurable disease, the management of MS predominantly focuses on reducing relapses and decelerating the progression of both physical and cognitive decline. The continuous autoimmune process modulated by cytokines seems to be a vital contributing factor to the development and relapse of multiple sclerosis. This review sought to summarize the role of selected interleukins in the pathogenesis and advancement of MS. Patients with MS in the active disease phase seem to exhibit an increased serum level of IL-2, IL-4, IL-6, IL-13, IL-17, IL-21, IL-22 and IL-33 compared to healthy controls and patients in remission, while IL-10 appears to have a beneficial impact in preventing the progression of the disease. Despite being usually associated with proinflammatory activity, several studies have additionally recognized a neuroprotective role of IL-13, IL-22 and IL-33. Moreover, selected gene polymorphisms of IL-2R, IL-4, IL-6, IL-13 and IL-22 were identified as a possible risk factor related to MS development. Treatment strategies of multiple sclerosis that either target or utilize these cytokines seem rather promising, but more comprehensive research is necessary to gain a clearer understanding of how these cytokines precisely affect MS development and progression.

Understanding the spectrum of non-motor symptoms in multiple sclerosis: insights from animal models

Multiple sclerosis is a chronic autoimmune disease of the central nervous system and is generally considered to be a non-traumatic, physically debilitating neurological disorder. In addition to experiencing motor disability, patients with multiple sclerosis also experience a variety of non-motor symptoms, including cognitive deficits, anxiety, depression, sensory impairments, and pain. However, the pathogenesis and treatment of such non-motor symptoms in multiple sclerosis are still under research. Preclinical studies for multiple sclerosis benefit from the use of disease-appropriate animal models, including experimental autoimmune encephalomyelitis. Prior to understanding the pathophysiology and developing treatments for non-motor symptoms, it is critical to characterize the animal model in terms of its ability to replicate certain non-motor features of multiple sclerosis. As such, no single animal model can mimic the entire spectrum of symptoms. This review focuses on the non-motor symptoms that have been investigated in animal models of multiple sclerosis as well as possible underlying mechanisms. Further, we highlighted gaps in the literature to explain the non-motor aspects of multiple sclerosis in experimental animal models, which will serve as the basis for future studies.

Multiple sclerosis and exercise-A disease-modifying intervention of mice or men?

Research suggests that physical exercise can promote an anti-inflammatory and neuroprotective state. If so, increasing or optimizing exercise could be considered a 'disease-modifying intervention' in neuroinflammatory diseases, such as multiple sclerosis (MS). Exercise intervention studies conducted in animal models of MS are promising. Various aerobic and strength training regimes have been shown to delay disease onset and to reduce both the clinical and pathological disease severity in mice. However, fundamental differences between the physiology of animals and humans, the disease states studied, and the timing of exercise intervention are significant. In animal models of MS, most exercise interventions begin before disease initiation and before any clinical sign of disease. In contrast, studies in humans recruit participants on average nearly a decade after diagnosis and often once disability is established. If, as is thought to be the case for disease-modifying treatments, the immunomodulatory effect of exercise decreases with advancing disease duration, current studies may therefore fail to detect the true disease-modifying potential. Clinical studies in early disease cohorts are needed to determine the role of exercise as a disease-modifying intervention for people with MS.

Mechanisms underlying the beneficial effects of physical exercise on multiple sclerosis: focus on immune cells

Multiple sclerosis (MS) is a prevalent neuroimmunological illness that leads to neurological disability in young adults. Although the etiology of MS is heterogeneous, it is well established that aberrant activity of adaptive and innate immune cells plays a crucial role in its pathogenesis. Several immune cell abnormalities have been described in MS and its animal models, including T lymphocytes, B lymphocytes, dendritic cells, neutrophils, microglia/macrophages, and astrocytes, among others. Physical exercise offers a valuable alternative or adjunctive disease-modifying therapy for MS. A growing body of evidence indicates that exercise may reduce the autoimmune responses triggered by immune cells in MS. This is partially accomplished by restricting the infiltration of peripheral immune cells into the central nervous system (CNS) parenchyma, curbing hyperactivation of immune cells, and facilitating a transition in the balance of immune cells from a pro-inflammatory to an anti-inflammatory state. This review provides a succinct overview of the correlation between physical exercise, immune cells, and MS pathology, and highlights the potential benefits of exercise as a strategy for the prevention and treatment of MS.

Current Perspectives on Pharmacological and Non-Pharmacological Interventions for the Inflammatory Mechanism of Unipolar Depression

Since depression remains a major public health issue there is a constant need for new and more efficient therapeutic strategies based on the mechanisms involved in the aetiology of depression. Thus, the pathogenic link between depression and inflammation is considered to play a potential key role in the development of such therapies. This review summarizes the results of various pharmacological (non-steroidal anti-inflammatory drugs, aspirin, cyclooxygenase inhibitors, cytokine inhibitors, corticosteroids, statins, minocycline, N-acetyl cysteine, omega-3 fatty acids and probiotics) and non-pharmacological interventions (electroconvulsive therapy, physical exercise and psychological therapy) and outlines their efficacy and discusses potential challenges. Both conventional and non-conventional anti-inflammatory drugs showed promising results according to the specific group of patients. The pre-existing pro-inflammatory status was, in most cases, a predictor for clinical efficacy and, in some cases, a correlation between clinical improvement and changes in various biomarkers was found. Some of the non-pharmacological interventions (physical exercise and electroconvulsive therapy) have also showed beneficial effects for depressive patients with elevated inflammatory markers. Treatments with anti-inflammatory action may improve clinical outcomes in depression, at least for some categories of patients, thus opening the way for a future personalised approach to patients with unipolar depression regarding the inflammation-related mechanism.