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Proinflammatory cytokines are implicated in promoting neurodegeneration in multiple sclerosis (MS) by affecting excitatory and inhibitory transmission at central synapses. Conversely, the synaptic effects of anti-inflammatory molecules remain underexplored, despite their potential neuroprotective properties and their presence in the cerebrospinal fluid (CSF) of patients. In a study involving 184 newly diagnosed relapsing-remitting (RR)-MS patients, we investigated whether CSF levels of the anti-inflammatory interleukin (IL)-10 were linked to disease severity and neurodegeneration measures. Additionally, we examined IL-10 impact on synaptic transmission in striatal medium spiny neurons and its role in counteracting inflammatory synaptopathy induced by IL-1β in female C57BL/6 mice with experimental autoimmune encephalomyelitis (EAE). Our findings revealed a significant positive correlation between IL-10 CSF levels and changes in EDSS (Expanded Disability Status Scale) scores one year after MS diagnosis. Moreover, IL-10 levels in the CSF were positively correlated with volumes of specific subcortical brain structures, such as the nucleus caudate. In both MS patients' CSF and EAE mice striatum, IL-10 and IL-1β expressions were upregulated, suggesting possible antagonistic effects of these cytokines. Notably, IL-10 exhibited the ability to decrease glutamate transmission, increase GABA transmission in the striatum, and reverse IL-1β-induced abnormal synaptic transmission in EAE. In conclusion, our data suggest that IL-10 exerts direct neuroprotective effects in MS patients by modulating both excitatory and inhibitory transmission and attenuating IL-1β-induced inflammatory synaptopathy. These findings underscore the potential therapeutic significance of IL-10 in mitigating neurodegeneration in MS. [ABSTRACT FROM AUTHOR]

(1) Multiple sclerosis (MS) is identified by a complex interaction between central inflammation and neurodegeneration. Genetic individual variability could play a significative role in clinical presentation. The interleukin-5 (IL-5) rs2069812 single-nucleotide polymorphism (SNP) seems to define the clinical course of Th2 autoimmune diseases, while its role in MS has never been investigated. (2) In a group of 230 patients diagnosed with relapsing–remitting MS (RR-MS) or progressive MS (P-MS) and controls (IC), rs2069812 polymorphism, cerebrospinal fluid (CSF) levels of inflammatory mediators, and clinical and demographic characteristics were determined. In RR-MS patients, No Evidence of Disease Activity (NEDA-3) at three years of follow-up was detected. (3) We identified higher levels of proinflammatory cytokines, particularly IL-2 (median [IQR], RR-MS = 0.2 [0–0.7]; P-MS = 0.1 [0–1.6]; IC = 0.1 [0.0–0.1]; p < 0.005), IL-6 (RR-MS = 0.9 [0.3–2.3]; P-MS = 0.8 [0.1–2.7]; IC = 0.1 [0.0–0.5]; p < 0.005), IL-12 (RR-MS = 0.5 [0–1.1]; P-MS = 0.5 [0–1.1]; IC = 0.0 [0.0–0.3]; p < 0.005), and GM-CSF (RR-MS = 15.6 [4.8–26.4]; P-MS = 14 [3.3–29.7]; IC = 8.9 [4.7–11.7]; p < 0.005) in MS patients compared with IC. Conversely, anti-inflammatory cytokines, specifically IL-5 (RR-MS = 0.65 [0–2.4]; P-MS = 0.1 [0–0.8]; IC = 1.7 [0.6–2.8]; p < 0.005) and IL-1ra (RR-MS = 14.7 [4.9–26.4]; P-MS = 13.1 [4.7–22.2]; IC = 27.8 [17.7–37.6]; p < 0.005) were higher in controls. According to rs2069812, in MS patients, the T-allele was associated with higher concentrations of proinflammatory mediators (IL-2, CT/TT = 0.2 [0.0–2.0]; CC = 0.1 [0.0–0.4], p = 0.015; IL-6, CT/TT = 1.2 [0.4–3.2] vs. CC = 0.7 [0.1–1.7], p = 0.007; IL-15, CT/TT = 0.1 [0.0–9.5] vs. CC = 0.0 [0.0–0.1], p = 0.019; and GM-CSF, CT/TT = 0.1 [0.0–0.6] vs. CC = 0.05 [0.0–0.1], p < 0.001), and CC was associated with anti-inflammatory mediators (IL-5, CT/TT = 0.03 [0.0–1.9] vs. CC = 1.28 [0.0–2.7], p = 0.001; IL-1ra, CT/TT = 12.1 [4.1–25.9] vs. CC = 18.1 [12.1–26.9], p = 0.006). We found the same differences in RR-MS patients (IL-2, T-allele median [IQR] = 0.3 [0.0–2.0] vs. C-allele, median [IQR] = 0.04 [0.0–0.3]; p = 0.005; IL-6, T-allele, median [IQR] = 1.3 [0.4–3.3] vs. C-allele, median [IQR] = 0.6 [0.03–1.5]; p = 0.001; IL-15, T-allele, median [IQR] = 0.1 [0.0–9.5] vs. C-allele, median [IQR] = 0.0 [0.0–0.1]; p = 0.008; GM-CSF, T-allele, median [IQR] = 0.1 [0.0–97.9] vs. C-allele, median [IQR] = 0.0 [0.0–0.001]; p < 0.001; IL-5, T-allele, median [IQR] = 0.02 [0.0–2.2] vs. C-allele, median [IQR] = 1.5 [0.0–2.9]; p = 0.016; and IL-1ra, T-allele, median [IQR] = 12.1 [4.3–26.4] vs. C-allele, median [IQR] = 18.5 [12.7–28.3]; p = 0.006) but not in P-MS, except for IL-5 (T-allele, median [IQR] = 0.1 [0–0.23] vs. C-allele, median [IQR] = 0.6 [0.0–2.5]; p = 0.022). Finally, we identified an association between CC in RR-MS patients and NEDA-3 after three years of follow-up (p = 0.007). (4) We describe, for the first time, the role of an SNP of the IL-5 gene in regulating central neuroinflammation and influencing clinical course in MS patients. [ABSTRACT FROM AUTHOR]

Introduction: The visual system is a prominent site of damage in MS since the earliest phases of the disease. Altered low-contrast visual acuity (LCVA) test has been associated with visual impairment and retinal degeneration, predicting medium- and long-term disability. However, it is unclear whether LCVA may also represent a reliable measure of neuroinflammation and a predictor of disease evolution in the very early stages of MS. Methods: We explored in a group of 76 consecutive newly diagnosed relapsing-- remitting MS (RR-MS) patients without visual impairment or altered visual evoked potentials, the association between LCVA scores at 2.5% and 1.25% and clinical characteristics, including prospective disability evaluated after 1- and 2 years of follow-up. Associations between LCVA and the CSF levels of IL-10 at diagnosis were also analyzed. Results: A negative correlation was found between LCVA at 2.5% and Expanded Disability Status Scale (EDSS) evaluated at first (Spearman's Rho= -0.349, p =0.005, n =62) and second year (Spearman's Rho= -0.418, p <0.001, n =62) of follow-up, and negative correlations were found with Multiple Sclerosis Severity Score (MSSS) at first (Spearman's Rho= -0.359, p =0.004, n =62) and second year (Spearman's Rho= -0.472, p <0.001, n=62). All the data were confirmed by a mixed effect model, considering other clinical variables. A positive correlation was found between the CSF concentrations of IL-10 and LCVA at 2.5% (Spearman's Rho=0.272, p =0.020, n =76), and 1.25% (Spearman's Rho, = 0.276, p =0.018, n=76), also evidenced in a linear regression. Discussion: In MS patients at diagnosis, altered LCVA may be associated with CSF inflammation and represent a useful parameter to identify patients with worse disease course. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Aim: We recently proposed miR‐142‐3p as a molecular player in inflammatory synaptopathy, a new pathogenic hallmark of multiple sclerosis (MS) and of its mouse model experimental autoimmune encephalomyelitis (EAE), that leads to neuronal loss independently of demyelination. MiR‐142‐3p seems to be unique among potential biomarker candidates in MS, since it is an inflammatory miRNA playing a dual role in the immune and central nervous systems. Here, we aimed to verify the impact of miR‐142‐3p circulating in the cerebrospinal fluid (CSF) of MS patients on clinical parameters, neuronal excitability and its potential interaction with disease modifying therapies (DMTs). Methods and Results: In a cohort of 151 MS patients, we found positive correlations between CSF miR‐142‐3p levels and clinical progression, IL‐1β signalling as well as synaptic excitability measured by transcranial magnetic stimulation. Furthermore, therapy response of patients with 'low miR‐142‐3p' to dimethyl fumarate (DMF), an established disease‐modifying treatment (DMT), was superior to that of patients with 'high miR‐142‐3p' levels. Accordingly, the EAE clinical course of heterozygous miR‐142 mice was ameliorated by peripheral DMF treatment with a greater impact relative to their wild type littermates. In addition, a central protective effect of this drug was observed following intracerebroventricular and ex vivo acute treatments of EAE wild type mice, showing a rescue of miR‐142‐3p‐dependent glutamatergic alterations. By means of electrophysiology, molecular and biochemical analysis, we suggest miR‐142‐3p as a molecular target of DMF. Conclusion: MiR‐142‐3p is a novel and potential negative prognostic CSF marker of MS and a promising tool for identifying personalised therapies. [ABSTRACT FROM AUTHOR]