Chronic fatigue and depression due to multiple sclerosis: Immune-inflammatory pathways, tryptophan catabolites and the gut-brain axis as possible shared pathways

Role of the gut microbiome in psychological symptoms associated with inflammatory bowel diseases

The brain-gut axis constitutes the basis for the bidirectional communication between the central nervous system and the gastrointestinal tract driven by neural, hormonal, metabolic, immunological, and microbial signals. Alterations in the gut microbiome composition as observed in inflammatory bowel diseases can modulate brain function and emerging empirical evidence has indicated that interactions among the brain-gut microbiome-axis seem to play a significant role in the pathogenesis of both inflammatory bowel diseases and psychiatric disorders and their comorbidity. Yet, the immunological and molecular mechanisms underlying the co-occurrence of inflammatory bowel diseases and psychological symptoms are still poorly understood. The aim of this narrative review is to highlight contemporary empirical findings supporting a pivotal role of the gut microbiome in the pathophysiology of highly prevalent neuropsychiatric symptoms in inflammatory bowel diseases such as fatigue, depression, and anxiety. Finally, we focus on microbiome modulation as potential treatment option for comorbid neuropsychiatric symptoms in immune-mediated diseases and especially in inflammatory bowel diseases. High-quality clinical trials are required to clarify how microbiome modulation through dietary interventions or probiotic, prebiotic or synbiotic treatment can be used clinically to improve mental health and thus quality of life of patients with inflammatory bowel diseases.

The tryptophan catabolite or kynurenine pathway in long COVID disease: A systematic review and meta-analysis

BACKGROUND

Recent studies confirm the involvement of activated immune-inflammatory responses and increased oxidative and nitrosative stress in Long COVID (LC) disease. However, the influence of these pathways on the metabolism of tryptophan (TRP) through the TRP catabolite (TRYCAT) pathway and their mediating effects on LC pathophysiology, has not been fully explored.

OBJECTIVE

This meta-analysis investigates peripheral TRP and TRYCAT levels and the TRYCAT pathway in patients with LC disease.

METHOD

This review utilized systematic searches of PubMed, Google Scholar, SCOPUS and SciFinder, including 14 full-text articles and 1,167 participants, consisting of 480 patients with LC and 687 normal controls.

RESULTS

The results indicated a significant increase in the kynurenine (KYN)/TRP ratio, with a large effect size (standardized mean difference, SMD = 0.755; confidence intervals, CI: 0.119;1.392), in LC patients compared to normal controls. Additionally, LC patients exhibited a significant decrease in TRP levels (SMD = -0.520, CI: -0.793; -0.246) and an increase in KYN levels after imputing missing studies (SMD = 1.176, CI: 0.474; 1.877), suggesting activation of the indoleamine 2,3-dioxygenase (IDO) enzyme and upregulation of the TRYCAT pathway. No significant elevation in TRYCAT-related neurotoxicity, kynurenic acid (KA)/KYN and 3-hydroxykynurenine (3-HK)/KYN ratios were observed in LC patients compared to normal controls.

CONCLUSION

The current findings suggest that an activated TRYCAT pathway, characterized by decreased TRP levels and maybe elevated KYN levels, plays a significant role in the pathophysiology of LC.

Detecting fatigue in multiple sclerosis through automatic speech analysis

Multiple sclerosis (MS) is a chronic neuroinflammatory disease characterized by central nervous system demyelination and axonal degeneration. Fatigue affects a major portion of MS patients, significantly impairing their daily activities and quality of life. Despite its prevalence, the mechanisms underlying fatigue in MS are poorly understood, and measuring fatigue remains a challenging task. This study evaluates the efficacy of automated speech analysis in detecting fatigue in MS patients. MS patients underwent a detailed clinical assessment and performed a comprehensive speech protocol. Using features from three different free speech tasks and a proprietary cognition score, our support vector machine model achieved an AUC on the ROC of 0.74 in detecting fatigue. Using only free speech features evoked from a picture description task we obtained an AUC of 0.68. This indicates that specific free speech patterns can be useful in detecting fatigue. Moreover, cognitive fatigue was significantly associated with lower speech ratio in free speech (ρ = -0.283, p = 0.001), suggesting that it may represent a specific marker of fatigue in MS patients. Together, our results show that automated speech analysis, of a single narrative free speech task, offers an objective, ecologically valid and low-burden method for fatigue assessment. Speech analysis tools offer promising potential applications in clinical practice for improving disease monitoring and management.

Attachment and negative affect on mental health and pain experience patients with Multiple Sclerosis: Mediated by coping strategies and loneliness

BACKGROUND

Multiple sclerosis and its related stressors significantly affect the mental health of people with MS. Considering the progressive and relapsing-remitting nature of the disease and somatic complaint, the Pain experience for MS patients is challenging. We examined the direct effects of Attachment and the negative affect on mental health and pain experience and the indirect effects of Attachment, negative affect, loneliness, and coping strategies on the mental health and pain experience of people with multiple sclerosis.

METHODS

Three hundred forty-five patients with MS were selected through the Iranian MS Association. Measures included the negative affect (PANAS), Adult Attachment Inventory (AAI), General Health Questionnaire (GHQ28), short-form McGill pain questionnaire (SF-mpq-2), Social and emotional loneliness scale for adults (SELSA-S), Coping Inventory for Stressful Situations(CISS-21). The present study has employed the Structural Equation Model (SEM) to investigate the direct and indirect effects of coping strategies, attachment, loneliness, and negative affect on mental health and pain experienced by individuals with MS. The fit of the model to the data was examined using the Discrepancy Function Divided by Degrees of Freedom (CMIN/DF), Normed Fit Index (NFI), TuckerLewis Index (TLI), Comparative Fit Index (CFI), and Root Mean Square Error of Approximation (RMSEA).

RESULTS

The fit indices results showed that the model's fit was good. Furthermore, findings indicate that 13 % (R2=13) of the pain experience Changes and 47 % (R2=47) of the mental health Changes are explained via study predictors. Negative affect directly affects mental health and pain experience, and Attachment directly affects mental health. Negative affect indirectly affects coping strategies. Attachment and Negative affect indirectly affect loneliness. Loneliness and coping strategies indirectly affect mental health and pain experience.

CONCLUSION

Study findings contribute to our understanding of the crucial structures that play a role in the mental health and pain experience of individuals with MS. Loneliness and coping strategies as mediating variables play essential roles in these people's mental health and pain experience. In the times ahead, it would be beneficial to prioritize addressing negative affect, attachment, coping strategies, and loneliness in the patients with MS' medical and psychological intervention.

Kynurenines as a Novel Target for the Treatment of Inflammatory Disorders

This review discusses the potential of targeting the kynurenine pathway (KP) in the treatment of inflammatory diseases. The KP, responsible for the catabolism of the amino acid tryptophan (TRP), produces metabolites that regulate various physiological processes, including inflammation, cell cycle, and neurotransmission. These metabolites, although necessary to maintain immune balance, may accumulate excessively during inflammation, leading to systemic disorders. Key KP enzymes such as indoleamine 2,3-dioxygenase 1 (IDO1), indoleamine 2,3-dioxygenase 2 (IDO2), tryptophan 2,3-dioxygenase (TDO), and kynurenine 3-monooxygenase (KMO) have been considered promising therapeutic targets. It was highlighted that both inhibition and activation of these enzymes may be beneficial, depending on the specific inflammatory disorder. Several inflammatory conditions, including autoimmune diseases, for which modulation of KP activity holds therapeutic promise, have been described in detail. Preclinical studies suggest that this modulation may be an effective treatment strategy for diseases for which treatment options are currently limited. Taken together, this review highlights the importance of further research on the clinical application of KP enzyme modulation in the development of new therapeutic strategies for inflammatory diseases.

Kynurenines and Inflammation: A Remarkable Axis for Multiple Sclerosis Treatment

Multiple sclerosis (MS) is a chronic inflammatory autoimmune neurological disease characterized by the recurrent appearance of demyelinating lesions and progressive disability. Currently, there are multiple disease-modifying treatments, however, there is a significant need to develop new therapeutic targets, especially for the progressive forms of the disease. This review article provides an overview of the most recent studies aimed at understanding the inflammatory processes that are activated in response to the accumulation of kynurenine pathway (KP) metabolites, which exacerbate an imbalance between immune system cells (e.g., Th1, Th2, and T reg) and promote the release of pro-inflammatory interleukins that modulate different mechanisms: membrane-receptors function; nuclear factors expression; and cellular signals. Together, these alterations trigger cell death mechanisms in brain cells and promote neuron loss and axon demyelination. This hypothesis could represent a remarkable approach for disease-modifying therapies for MS. Here, we also provide a perspective on the repositioning of some already approved drugs involved in other signaling pathways, which could represent new therapeutic strategies for MS treatment.

Changes in tryptophan breakdown associated with response to multimodal treatment in depression

Background

Research on depression showed that dysregulations in tryptophan (TRP), kynurenine (KYN), and its KYN pathway metabolites are key aspects in the development and maintenance of depressive symptoms. In our previous reports, we described sex-specific changes in TRP breakdown as well as changes in KYN and KYN/TRP in association with treatment response and inflammatory and metabolic parameters. However, results of treatment effects on KYN pathway metabolites as well as how pathway changes are related to treatment response remain sparse.

Objective

We investigated potential changes of KYN and KYN pathway metabolites in association with therapeutic response of individuals with depression during a six-week multimodal psychiatric rehabilitation program.

Methods

87 participants were divided into treatment responders and non-responders (48 responders, 39 non-responders; 38 male, 49 female; M age = 51.09; SD age = 7.70) using scores of psychological questionnaires. KYN pathway metabolites serum concentrations as well as their ratios were collected using high performance liquid chromatography. Changes over time (time of admission (t1) vs. time of discharge (t2)) were calculated using repeated measure analyses of (co)variance.

Results

Non-responders exhibited higher levels of 3-Hydroxyanthralinic acid (3-HAA), nicotinic acid (NA), and 3-HAA/KYN, independently of measurement time. NA levels decreased, while 3-HAA levels increased over time in both groups, independently of treatment response. 3-HK/KYN levels decreased, while KYN levels increased in non-responders, but not in responders over time.

Discussion

The results indicate that some compounds of the KYN pathway metabolites can be altered through multimodal long-term interventions in association with treatment response. Especially the pathway degrading KYN further down to 3-HAA and 3-HK/KYN might be decisive for treatment response in depression.

Prevalence and risk factors of depression among patients with perianal fistulizing Crohn's disease

BACKGROUND

Psychological distress, especially depression, associated with perianal fistulizing Crohn's disease (PFCD) is widespread and refractory. However, there is a surprising paucity of studies to date that have sought to identify the prevalence and risk factors of depression associated with PFCD.

AIM

To estimate the prevalence of depressive symptoms and investigate the depression-related risk factors in patients with PFCD.

METHODS

The study was conducted in the form of survey and clinical data collection via questionnaire and specialized medical staff. Depressive symptoms, life quality, and fatigue severity of patients with PFCD were assessed by Patient Health Questionnaire-9, Inflammatory Bowel Disease Patient Quality of Life Questionnaire (IBDQ), and Inflammatory Bowel Disease (IBD) Fatigue Patient Self-assessment Scale. The basic demographic information, overall disease features, perianal clinical information, and laboratory inflammation indicators were also gathered. Multivariate regression analysis was ultimately used to ascertain the risk factors of depression associated with PFCD.

RESULTS

A total of 123 patients with PFCD were involved, and 56.91% were suffering from depression. According to multivariate logistic regression analysis, Perianal Disease Activity Index (PDAI) score [odds ratio (OR) = 0.69, 95% confidence interval (CI): 0.50 to 0.95], IBDQ score (OR = 0.93, 95%CI: 0.88 to 0.97), modified Van Assche index (OR = 1.24, 95%CI: 1.01 to 1.53), and IBD Fatigue score (OR = 1.72, 95%CI: 1.23 to 2.42) were independent risk factors of depression-related prevalence among patients with PFCD (P < 0.05). Multiple linear regression analysis revealed that the increasing perianal modified Van Assche index (β value = 0.166, 95%CI: 0.02 to 0.31) and decreasing IBDQ score (β value = -0.116, 95%CI: -0.14 to -0.09) were independently associated with the severity of depression (P < 0.05).

CONCLUSION

Depressive symptoms in PFCD patients have significantly high prevalence. PDAI score, modified Van Assche index, quality of life, and fatigue severity were the main independent risk factors.

Risk of depression and anxiety in multiple sclerosis and neuromyelitis optica spectrum disorder: A nationwide cohort study in South Korea

BACKGROUND

We investigated the risks of depression/anxiety in patients with multiple sclerosis (pwMS) or patients with neuromyelitis optica spectrum disorder (pwNMOSD).

OBJECTIVES

MS/NMOSD cohorts were collected from Korean National Health Insurance Service, using the International Classification of Diseases-10th and information on Rare Intractable Disease program. Patients who were younger than 20 years, had a previous depression/anxiety, or died in the index year were excluded.

METHODS

Hazard ratios (HRs) of depression/anxiety in pwMS and pwNMOSD from controls matched 1:5 for age, sex, hypertension, diabetes, and dyslipidemia were calculated using Cox regressions with a 1-year lag period and estimated over time.

RESULTS

During a mean follow-up of 4.1 years, adjusted hazard ratios (aHR) for depression were 3.25 (95% confidence interval (CI) = 2.59-4.07) in MS and 2.17 (1.70-2.76) in NMOSD, and aHRs for anxiety were 1.83 (1.49-2.23) in MS and 1.56 (1.26-1.91) in NMOSD. The risks of anxiety/depression did not differ between MS and NMOSD and were highest in the second year after diagnosis of MS/NMOSD. The relative risk of depression was higher in younger pwMS/pwNMOSD, and the relative risk of anxiety was higher in pwMS who was male, had low income, or lived in a non-urban area.

CONCLUSION

The risk of depression and anxiety was increased in pwMS/pwNMOSD.

Why does malaise/fatigue occur? Underlying mechanisms and potential relevance to treatments in rheumatoid arthritis

INTRODUCTION

Fatigue and malaise are commonly associated with a wide range of medical conditions, including rheumatoid arthritis (RA). Evidence suggests that fatigue and malaise can be overwhelming for patients, yet these symptoms remain inadequately-managed, largely due to an incomplete elucidation of the underlying causes.

AREAS COVERED

In this assessment of the published literature relating to the pathogenesis of fatigue or malaise in chronic conditions, four key mechanistic themes were identified. Each theme (inflammation, hypothalamic-pituitary-adrenal axis, dysautonomia, and monoamines) is discussed, as well as the complex network of interconnections between themes which suggests a key role for inflammatory cytokines in the development and persistence of fatigue.

EXPERT OPINION

Fatigue is multifaceted, poorly defined, and imperfectly comprehended. Moreover, the cause and severity of fatigue may change over time, as a consequence of the natural disease course or pharmacologic treatment. This detailed synthesis of available evidence permits us to identify avenues for current treatment optimization and future research, to improve the management of fatigue and malaise in RA. Within the development pipeline, several new anti-inflammatory therapies are currently under investigation, and we anticipate that the next five years will herald much-needed progress to reduce the debilitating nature of fatigue in patients with RA.

Sleep Disturbance and Related Factors in the Patients with Relapsing-Remitting Multiple Sclerosis

Background. Sleep disturbances are commonly reported, although underestimated complaints from people with multiple sclerosis (MS). The aim of the study was to analyze the frequency and type of sleep disturbances in MS patients and to evaluate their relationships with demographics and clinical data. Methods. The study group consisted of 178 patients with relapsing-remitting MS: 130 females and 48 males. Clinical measures (disease duration, disability level in Expanded Disability Status Scale (EDSS), and treatment) were acquired from medical records. The questionnaire was applied, containing questions about sleep disturbances, somatic complaints, perception of fatigue, depression, anxiety, and problems at work and in social/family life. Athens Insomnia Scale (AIS) and Karolinska Sleepiness Scale (KSS) were performed to quantify sleep problems and Hamilton Depression Rating Scale (HDRS) and Addenbrooke’s Cognitive Examination (Mini-ACE) to assess level of depression and cognitive performance. Electroencephalography was recorded to identify electrophysiological indices of sleep. Results. 109 patients (61%) reported sleep disturbances, most frequently insomnia, snoring, and parasomnias. This subgroup had significantly higher scores in AIS ($p<0.0001$) and KSS ($p=0.010$) and slightly higher EDSS score ($p=0.048$) and more often complained of fatigue (71% vs. 53%, $p=0.0148$), involuntary limb movement (42% vs. 25, $p=0.0170$), and breathing disturbances (10% vs. 0%). There was a significant correlation between the results of AIS and HDRS ($\text{Rs}=0.715$, $p<0.05$). Conclusion. Sleep disturbances, predominantly insomnia, are reported by more than a half of the patients with relapsing-remitting MS. Significant associations were found between sleep problems and MS-related clinical symptoms and psychosocial issues.

Analysis of tryptophan metabolites and related compounds in human and murine tissue: development and validation of a quantitative and semi-quantitative method using high resolution mass spectrometry

This study explores the metabolic differences between human and murine plasma in addition to differences between murine subcutaneous and visceral white adipose tissue. A quantitative and semi-quantitative targeted method was developed and validated for this purpose. The quantitative method includes tryptophan and its metabolites in addition to tyrosine, phenylalanine, taurine, B vitamins, neopterin, cystathionine and hypoxanthine. While the semi-quantitative method includes; 3-indoleacetic acid, 5-hydroxyindoleacetic acid, acetylcholine, asymmetric dimethylarginine, citrulline and methionine. Sample preparation was based on protein precipitation, while quantification was conducted using ultrahigh-performance liquid chromatography coupled to a quadrupole Orbitrap tandem mass spectrometer with electrospray ionization in the parallel reaction monitoring (PRM) mode. The low limit of quantification for all metabolites ranged from 1 to 200 ng mL-1. Matrix effects and recoveries for stable isotope labelled internal standards were evaluated, with most having a coefficient of variation (CV) of less than 15%. Results showed that a majority of the analytes passed both the intra- and interday precision and accuracy criteria. The comparative analysis of human and murine plasma metabolites reveals species-specific variations within the tryptophan metabolic pathway. Notably, murine plasma generally exhibits elevated concentrations of most compounds in this pathway, with the exceptions of kynurenine and quinolinic acid. Moreover, the investigation uncovers noteworthy metabolic disparities between murine visceral and subcutaneous white adipose tissues, with the subcutaneous tissue demonstrating significantly higher concentrations of tryptophan, phenylalanine, tyrosine, and serotonin. The findings also show that even a semi-quantitative method can provide comparable results to quantitative methods from other studies and be effective for assessing metabolites in a complex sample. Overall, this study provides a robust platform to compare human and murine metabolism, providing a valuable insight to future investigations.

A randomized open-label clinical trial on the effect of Amantadine on post Covid 19 fatigue

Many COVID-19 survivors experience lingering post-COVID-19 symptoms, notably chronic fatigue persisting for months after the acute phase. Despite its prevalence, limited research has explored effective treatments for post-COVID-19 fatigue. This randomized controlled clinical trial assessed the impact of Amantadine on patients with post-COVID-19 fatigue. The intervention group received Amantadine for two weeks, while the control group received no treatment. Fatigue levels were assessed using the Visual Analog Fatigue Scale (VAFS) and Fatigue Severity Scale (FSS) questionnaires before and after the trial. At the study's onset, VAFS mean scores were 7.90 ± 0.60 in the intervention group and 7.34 ± 0.58 in the control group (P-value = 0.087). After two weeks, intervention group scores dropped to 3.37 ± 0.44, significantly lower than the control group's 5.97 ± 0.29 (P-value < 0.001). Similarly, FSS mean scores at the trial's commencement were 53.10 ± 5.96 in the intervention group and 50.38 ± 4.88 in the control group (P-value = 0.053). At the trial's end, intervention group scores decreased to 28.40 ± 2.42, markedly lower than the control group's 42.59 ± 1.50 (P-value < 0.001). In this study, we report the safety, tolerability, and substantial fatigue-relieving effects of Amantadine in post-COVID-19 fatigue. The intervention demonstrates a statistically significant reduction in fatigue levels, suggesting Amantadine's potential as an effective treatment for this persistent condition.

"No association between disease modifying treatment and fatigue in multiple sclerosis"

BACKGROUND

Fatigue affects 60-90% of people with multiple sclerosis (MS). It reduces quality of life and the ability to work. The cause of fatigue in MS remains unknown. Several disease-modifying treatments (DMTs) slow the disease process in relapsing MS by suppressing neuroinflammation. We aimed to investigate if treatment with a DMT is associated with lower rates of fatigue.

METHODS

In this cross-sectional study of the MS population in three counties in Norway, we used the Fatigue Scale for Motor and Cognitive Functions (FSMC) and the Hospital Anxiety and Depression Scale (HADS) to assess patient-reported fatigue, anxiety and depression. Clinical data were retrieved from the electronic patient record system. We categorized DMTs as high-efficacy therapy or moderate-efficacy therapy. High-efficacy drugs included fingolimod, natalizumab, ocrelizumab, rituximab, alemtuzumab, daclizumab, and autologous hematopoietic stem cell transplantation. Moderate-efficacy drugs included interferons, glatiramer acetate, dimethyl fumarate, and teriflunomide. We included persons with relapsing MS only.

RESULTS

Of 1142 patients, 80% had fatigue. Fifty-six percent of the patients were on DMTs (25% on moderate-efficacy treatment and 30% on high-efficacy treatment), 18% had discontinued treatment and 26% had never received any DMT. Sex, level of disability as measured by the Multiple Sclerosis Severity Score, anxiety and depression were independently associated with fatigue. Moderate-efficacy treatment was associated with less fatigue, but not after adjustment for other variables. There was no association between high-efficacy treatment and fatigue.

CONCLUSION

We found no independent relationship between the use of disease-modifying treatment and fatigue in MS.

Emotional competencies in multiple sclerosis

BACKGROUND

Emotional competencies (i.e., understanding emotions in self and others) are crucial for psychological well-being and successful social interaction. However, despite the deficits in psychological well-being and social interaction among individuals with multiple sclerosis (MS), emotional competencies have not been broadly investigated in MS. The present study: (1) compared emotional competencies between persons with MS and (a) previously published norms for the general population and (b) persons with major depressive disorder; and (2) investigated the association between emotional competencies and symptoms of insomnia, depression, fatigue, and paresthesia in persons with MS.

METHODS

The sample of 1135 persons with MS (mean age: 34.6 years; 81.1% female; median EDSS: 2; range: 0 - 5) self-rated emotional competencies and symptoms of insomnia, symptoms of depression, fatigue, and paresthesia. Data on emotional competencies of historical samples (general population: N = 622; mean age: 22.0 years; 61% females; outpatients with major depressive disorders (MDD); N = 50; mean age: 42.46 years; 68% females) were used for comparison.

RESULTS

Persons with MS reported lower levels of emotional competencies than both the general population (t (1, 1756) = 55.18, p < 0.001, d = 1.66; large effect size) and outpatients with MDD (t (1, 1183) = 3.48, p <0.001, d = 0.50; medium effect size). Among persons with MS, lower levels of emotional competencies were associated with higher MS-related symptoms of insomnia(r = - 0.24; p < 0.001), depression (r = - 0.42; p < 0.001), fatigue (r = - 0.31; p < 0.001), and paresthesia (r = - 0.18; p < 0.001).

CONCLUSIONS

Persons with MS reported significantly lower scores for emotional competencies when compared with the general population and outpatients with MDD. Further, lower scores for emotional competencies were associated with typical MS-related symptoms of insomnia, depression, fatigue and paresthesia. These findings suggest that emotional competencies may be an important target for intervention in persons with MS.

Neuropsychiatric and Neurological Diseases in Relation to the Microbiota-Gut-Brain Axis: From Research to Clinical Care

Neurological disease is on the upswing, the second leading cause of mortality and a significant cause of disability. The term gut-brain axis emphasizes a dynamic two-way communication between the central nervous system and the gastrointestinal system. The microbiome is being linked to more and more clinical and preclinical studies as a major risk factor for neurological diseases. Overall, 288 studies were identified initially. After screening, data extraction, and applying the inclusion and exclusion criteria, 37 articles were included in the study. Changes in the gut microbial population composition have been correlated to many neurological and neurodevelopmental diseases.

Mood Symptoms and Chronic Fatigue Syndrome Due to Relapsing-Remitting Multiple Sclerosis Are Associated with Immune Activation and Aberrations in the Erythron

BACKGROUND

Multiple sclerosis (MS) is a chronic autoimmune and neuroinflammatory disease of the central nervous system characterized by peripheral activation of immune-inflammatory pathways which culminate in neurotoxicity causing demyelination of central neurons. Nonetheless, the pathophysiology of relapsing-remitting MS (RRMS)-related chronic fatigue, depression, anxiety, cognitive impairments, and autonomic disturbances is not well understood.

OBJECTIVES

The current study aims to delineate whether the remitted phase of RRMS is accompanied by activated immune-inflammatory pathways and if the latter, coupled with erythron variables, explain the chronic fatigue and mood symptoms due to RRMS.

MATERIAL AND METHODS

We recruited 63 MS patients, 55 in the remitted phase of RRMS and 8 with secondary progressive MS, and 30 healthy controls and assessed erythron variables, and used a bio-plex assay to measure 27 serum cytokines.

RESULTS

A significant proportion of the MS patients (46%) displayed activation of the immune-inflammatory response (IRS) and compensatory immune response (CIRS) systems, and T helper (Th)1 and Th17 cytokine profiles. Remitted RRMS patients showed increased chronic fatigue, depression, anxiety, physiosomatic, autonomic, and insomnia scores, which could partly be explained by M1 macrophage, Th1, Th-17, growth factor, and CIRS activation, as well as aberrations in the erythron including lowered hematocrit and hemoglobin levels.

CONCLUSIONS

Around 50% of remitted RRMS patients show activation of immune-inflammatory pathways in association with mood and chronic-fatigue-like symptoms. IRS and CIRS activation as well as the aberrations in the erythron are new drug targets to treat chronic fatigue and affective symptoms due to MS.

Tryptophan catabolites, inflammation, and insulin resistance as determinants of chronic fatigue syndrome and affective symptoms in long COVID

Critical COVID-19 disease is accompanied by depletion of plasma tryptophan (TRY) and increases in indoleamine-dioxygenase (IDO)-stimulated production of neuroactive tryptophan catabolites (TRYCATs), including kynurenine (KYN). The TRYCAT pathway has not been studied extensively in association with the physiosomatic and affective symptoms of Long COVID. In the present study, we measured serum TRY, TRYCATs, insulin resistance (using the Homeostatic Model Assessment Index 2-insulin resistance, HOMA2-IR), C-reactive protein (CRP), physiosomatic, depression, and anxiety symptoms in 90 Long COVID patients, 3-10 months after remission of acute infection. We were able to construct an endophenotypic class of severe Long COVID (22% of the patients) with very low TRY and oxygen saturation (SpO2, during acute infection), increased kynurenine, KYN/TRY ratio, CRP, and very high ratings on all symptom domains. One factor could be extracted from physiosomatic symptoms (including chronic fatigue-fibromyalgia), depression, and anxiety symptoms, indicating that all domains are manifestations of the common physio-affective phenome. Three Long COVID biomarkers (CRP, KYN/TRY, and IR) explained around 40% of the variance in the physio-affective phenome. The latter and the KYN/TRY ratio were significantly predicted by peak body temperature (PBT) and lowered SpO2 during acute infection. One validated latent vector could be extracted from the three symptom domains and a composite based on CRP, KYN/TRY, and IR (Long COVID), and PBT and SpO2 (acute COVID-19). In conclusion, the physio-affective phenome of Long COVID is a manifestation of inflammatory responses during acute and Long COVID, and lowered plasma tryptophan and increased kynurenine may contribute to these effects.

Stress, Asthenia, and Cognitive Disorders

Asthenia is a clinical syndrome that can be manifest in almost all somatic, infectious, and neurological diseases. Initially a protective mechanism indicating depletion of energy resources, asthenia can become a pathological and extremely disabling condition, and can even progress to an independent immune-mediated disease - chronic fatigue syndrome. Asthenia is often combined with affective and cognitive disorders, producing diagnostic difficulties. The article addresses the complex interweaving of asthenia, chronic fatigue syndrome, and cognitive and affective disorders.

The borderland of multiple sclerosis and functional neurological disorder: A call for clinical research and vigilance

BACKGROUND AND PURPOSE

Functional neurological disorders (FNDs) have attracted much attention from the neurological medical community over the last decades as new developments in neurosciences have reduced stigma around these by showing brain network dysfunctions. An overlap with other neurological conditions such as multiple sclerosis (MS) is well known by clinicians but there is a lack of clinical and fundamental research in this field to better define diagnosis and therapeutic decisions, as well as a lack of deep understanding of the underlying pathophysiology.

AIM

We aimed to provide a critical commentary on the state of knowledge about the borderland between FNDs and MS.

METHODS

We based our commentary on a joint point of view between an FND specialist and an MS expert.

RESULTS

A brief review of the previous literature and relevant new studies covering the overlap between FNDs and MS is presented, along with suggestions for future research directions.

CONCLUSION

There are clear diagnostic criteria for both FNDs and MS and a strict application of these will help better diagnosis and prevent unnecessary treatment escalation in MS or absence of referral to multimodal therapy in FND. Better teaching of younger neurologists is needed as well as prospective research focusing on pathophysiology.

Possible role of the NLRP3 inflammasome and the gut-brain axis in multiple sclerosis-related depression

Multiple sclerosis (MS) is an autoimmune and demyelinating disease of the central nervous system that results from complex interactions between genetic and environmental determinants. Patients with MS exhibit a high risk of depression, however, the exact pathomechanisms remain largely unknown. It is becoming widely accepted that the gut-brain axis (GBA) disorders may exert an influence on neuroinflammation and psychiatric symptoms, including so-called MS-related depression. The element suggested as a bridge between intestinal disorders, depression, and MS is an inflammatory response with the central role of the NLR family pyrin domain containing 3 (NLRP3) inflammasome. The pro-inflammatory activity of effector cytokines of the NLRP3 inflammasome forms the hypothesis that it is actively involved in the development of inflammatory and autoimmune diseases. Despite extensive reviews considering the possible origins of MS-related depression, its complex pathophysiology prevents any easy determination of its underlying mechanisms. This paper aims to discuss molecular mechanisms related to the GBA axis that can mediate dysbiosis, intestinal barrier dysfunction, disruption of blood-brain barrier integrity, neuroinflammation, and subsequent manifestation of MS-related major depressive disorder.

A systematic review with meta-analysis on balance, fatigue, and motor function following aquatic therapy in patients with multiple sclerosis

OBJECTIVE

In this systematic review and meta-analysis, we aimed to evaluate the impact of long-term aquatic exercise training on balance, fatigue, and motor function.

METHODS

Scopus, PubMed, Web of Science, Cochrane Central Register of Controlled Trials, Ovid Medline, EBSCO Cumulative Index to Nursing, and Allied Health Literature were searched on April 19, 2021. The search included randomized and non-randomized controlled trials, case-control studies, case series, and case reports. Two independent reviewers reviewed titles and abstracts to determine which studies satisfied the eligibility criteria. Two reviewers independently surveyed the full texts and conducted the study selection, data extraction, and quality assessment. Data synthesis was applied to summarize information from included studies. Meta-analysis was performed using RevMan 5.

RESULTS

From 170 studies that were identified in the initial search, 16 trials (794 participants) satisfied the eligibility criteria. Aquatic therapy had a positive effect on fatigue compared to control group based on Modified Fatigue Impact Scale (MFIS) in physical (SMD, -1.29; 95% CI, [(-1.65) - (-0.93)]; I²=88%) cognitive (SMD, -0.75; 95% CI, [(-1.08)-(- 0.43)]; I²=78%), and psychological (SMD, -1.25; 95% CI, [(-1.59) - (-0.90)]; I²=79%) domains, and Fatigue Severity Scale (FSS) (SMD, -0.53; 95% CI, [(-0.86) - (-0.20)]; I²=57%). In addition, aquatic therapy improved balance based on the Berg Balance Scale (BBS) compared to the control group (SMD, 1.19; 95% CI, [(0.62)-(1.76)]; I²=11%) CONCLUSIONS: Aquatic therapy has positive effects on fatigue and balance. Further research is needed to confirm the clinical utility of aquatic therapy for multiple sclerosis patients in the long term.

Thermoregulatory dynamics reveal sex-specific inflammatory responses to experimental autoimmune encephalomyelitis in mice: Implications for multiple sclerosis-induced fatigue in females

The course of multiple sclerosis (MS) is characterized by striking sex differences in symptoms such as fatigue and impaired thermal regulation, which are associated with aggravated systemic pro-inflammatory processes. The purpose of this study was to replicate these symptoms in experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice in the quest to advance the preclinical study of non-motor symptoms of MS. Male and female C57BL/6 mice exposed to a mild form of EAE were evaluated for the progression of clinical, behavioural, thermal, and inflammatory processes. We show higher susceptibility in females to EAE than males based on greater clinical score and cumulative disease index (CDI), fatigue-like and anxiety-like behaviours. Accordingly, infrared (IR) thermography indicated higher cutaneous temperatures in females from post-induction days 12-23. Females also responded to EAE with greater splenic and adrenal gland weights than males as well as sex-specific changes in pro- and anti-inflammatory cytokines. These findings provide the first evidence of a sex-specific thermal response to immune-mediated demyelination, thus proposing a non-invasive assessment approach of the psychophysiological dynamics in EAE mice. The results are discussed in relation to the thermoregulatory correlates of fatigue and how endogenously elevated body temperature without direct heat exposure may be linked to psychomotor inhibition in patients with MS.

Fluvoxamine and Amantadine: Central Nervous System Acting Drugs Repositioned for COVID-19 as Early Intervention

BACKGROUND

As the World faces unprecedented pandemic caused by SARS-CoV-2 virus, repositioning of existing drugs to treatment of COVID-19 disease is urgently awaited, provided that high quality scientific evidence supporting safety and efficacy in this new indication is gathered. Efforts concerning drugs repositioning to COVID-19 were mostly focused on antiviral drugs, or drugs targeting the late phase of the disease.

METHODS

Based on published research, the pharmacological activities of fluvoxamine and amantadine, two well-known drugs widely used in clinical practice for psychiatric and neurological diseases, respectively, have been reviewed, with a focus on their potential therapeutic importance in the treatment of COVID-19.

RESULTS

Several preclinical and clinical reports were identified suggesting that these two drugs might exert protective effects in the early phases of COVID-19.

CONCLUSION

Preclinical and early clinical evidence are presented indicating that these drugs hold promise to prevent COVID-19 progression when administered early during the course of infection.

Validation of the fatigue severity scale in Croatian population of patients with multiple sclerosis disease: Factor structure, internal consistency, and correlates

BACKGROUND

Fatigue is a common symptom in people with multiple sclerosis (MS) and is evaluated and monitored with self-report questionnaires. The objective of this study was to determine the psychometric properties of the Croatian version of the Fatigue Severity Scale (FSS) in people with MS.

MATERIAL AND METHODS

This is a retrospective cohort study conducted as an online survey from December 16, 2020, until January 13, 2021. A total of 179 people with MS and 999 control subjects completed FSS and self-administered questionnaires capturing information of demographic, education level, disease-related variables (duration of the disease, MS type, the expanded disability status scale (EDSS), and Multiple Sclerosis Impact Scale-29 (MSIS-29). Psychometric properties were examined by estimating the validity, reliability, and factor structure of the FSS scale in people with MS.

RESULTS

The Croatian version of the FSS had excellent internal consistency (Cronbach's α value 0.93). Factor analysis demonstrated a unidimensional structure. The concurrent validity of the FSS appeared to be satisfactory due to the significant differences between people with MS and control subjects (p < .05). The correlations between FSS and MSIS-29 physical (r = 0.60) and psychological (r = 0.50) subscale results confirmed the convergent validity of the FSS scale. Results also indicated that the best cut-off score is between 4 and 5 with a relatively high sensitivity and specificity.

CONCLUSIONS

The Croatian version of FSS was shown to have excellent psychometric properties in people with MS and can be used in the research and clinical settings evaluating fatigue in people with MS in Croatia.

Shared Molecular Mechanisms of Hypertrophic Cardiomyopathy and Its Clinical Presentations: Automated Molecular Mechanisms Extraction Approach

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiovascular disease with a prevalence of 1 in 500 people and varying clinical presentations. Although there is much research on HCM, underlying molecular mechanisms are poorly understood, and research on the molecular mechanisms of its specific clinical presentations is scarce. Our aim was to explore the molecular mechanisms shared by HCM and its clinical presentations through the automated extraction of molecular mechanisms. Molecular mechanisms were congregated by a query of the INDRA database, which aggregates knowledge from pathway databases and combines it with molecular mechanisms extracted from abstracts and open-access full articles by multiple machine-reading systems. The molecular mechanisms were extracted from 230,072 articles on HCM and 19 HCM clinical presentations, and their intersections were found. Shared molecular mechanisms of HCM and its clinical presentations were represented as networks; the most important elements in the intersections’ networks were found, centrality scores for each element of each network calculated, networks with reduced level of noise generated, and cooperatively working elements detected in each intersection network. The identified shared molecular mechanisms represent possible mechanisms underlying different HCM clinical presentations. Applied methodology produced results consistent with the information in the scientific literature.

Fatigue in patients with inflammatory bowel disease in Eastern China

BACKGROUND

Fatigue is a very common but relatively neglected problem in patients with inflammatory bowel disease (IBD). The prevalence rate of IBD in China is the highest in Asia, but there is little research on fatigue in patients with IBD. Neither the relationship between fatigue and quality of life (QoL) nor the relationship between fatigue and work productivity (WP) in Chinese IBD patients has been reported.

AIM

To investigate the prevalence of fatigue related to IBD in Eastern China, to identify the risk factors associated with fatigue, to assess the impact of fatigue on QoL, and to evaluate the relationship between fatigue and WP.

METHODS

A cross-sectional study was conducted in a Regional Tertiary IBD Diagnostic and Treatment Center in Eastern China. Clinical data of patients were collected, and disease activity was evaluated. Blood samples were analyzed to assess anemia, albumin, and inflammation. Fatigue was assessed using the multidimensional fatigue inventory. QoL and WP were measured using the short inflammatory bowel disease questionnaire and the work productivity and activity impairment general health questionnaire, respectively. The patients also completed assessments of depression (Patient Health Questionnaire-9) and anxiety (Generalized Anxiety Disorder 7-item Scale).

RESULTS

A total of 311 IBD patients, comprising 168 Crohn's disease patients and 143 ulcerative colitis patients, were enrolled. The prevalence of fatigue in patients with IBD was 60.77%. In a univariate logistic regression analysis, factors such as disease activity, depression, anxiety, anemia, and IBD-related surgery were individually related to a significantly increased risk of fatigue in IBD patients. Multivariate logistic regression analysis indicated that depression [odds ratio (OR) = 8.078, 95% confidence interval (CI): 4.113-15.865], anxiety (OR = 2.373, 95%CI: 1.100-5.119), anemia (OR = 2.498, 95%CI: 1.290-4.834), and IBD-related surgery (OR = 2.035, 95%CI: 1.084-3.819) were related to fatigue in IBD patients. There was a negative correlation between fatigue and QoL (r = -0.831; P < 0.0001) but a positive correlation between fatigue and WP loss.

CONCLUSION

The prevalence of fatigue in IBD patients in Eastern China is remarkably high even in clinical remission. Factors such as depression, anxiety, anemia, and IBD-related surgery are major risk factors for fatigue in IBD patients. In addition, fatigue has a negative impact on QoL and is positively correlated with WP loss.