A Role of Cytokine Gene Polymorphisms in Cognitive Functioning.

The changes in cognitive functions that occur with aging and in various pathological conditions are a subject of growing interest. Experimental and clinical data justify the hypothesis about the influence the immune system exerts on cognitive processes. The balance between pro-inflammatory and anti-inflammatory cytokines has been established as a necessary factor for normal cognitive functioning. Cytokine production is under strong genetic control and various single nucleotide polymorphisms (SNPs) in cytokine genes have been described. As cytokine SNPs have been demonstrated to affect the gene expression or the functional activity of the immune protein this logically led to the suggestion about the role of these polymorphisms in cognitive functioning. Studies exploring the association between different genetic variants of cytokine gene polymorphisms and cognitive abilities in healthy subjects and in demented patients show divergent results. The review of relevant literature suggests that SNPs implement their effect on cognition in large interactions with each other, as well as with many other factors, some of which still remain to be identified. This article summarizes the contemporary knowledge about the correlations between SNPs in cytokine genes and cognitive status in humans. Further research is needed to determine the precise role and the molecular mechanisms of action of the SNPs in cognitive processes.

Cognitive Impairment in Multiple Sclerosis.

Multiple sclerosis (MS) is a socially significant immune-mediated disease, characterized by demyelination, axonal transection and oligodendropathy in the central nervous system. Inflammatory demyelination and neurodegeneration lead to brain atrophy and cognitive deficit in up to 75% of the patients. Cognitive dysfunctions impact significantly patients' quality of life, independently from the course and phase of the disease. The relationship between pathological brain findings and cognitive impairment is a subject of intensive research. Summarizing recent data about prevalence, clinical specificity and treatment of cognitive disorders in MS, this review aims to motivate the necessity of early diagnosis and complex therapeutic approach to these disturbances in order to reduce the social burden of the disease.

Vitamin D immunomodulatory potential in multiple sclerosis.

Multiple sclerosis (MS) is an autoimmune disease of unknown etiology whose treatment is of limited efficiency and therefore has a high social burden. As it has been suggested that myelin destruction model, the clinical manifestation and the potential of therapeutic response in MS are correlated, it is quite justifiable that we study various factors (genetic, hormonal, environmental) that take part in the autoimmune process in order to improve the control over the disrupted immune regulation. Results from epidemiological and clinical studies clearly suggest that changes in vitamin D serum concentrations are correlated with the magnitude of the risk of developing MS, the phases of relapse and remittance and with gender differences in vitamin D metabolism. Experimental and clinical studies also have established that 25-hydroxy vitamin D (25(OH)D) and 1,25-dihydroxy vitamin D (1,25(OH)2D) exert an immunomodulatory effect in the central nervous system and peripheral organs of the immune system. The standard reference range of vitamin D concentration in serum is 50-80 nmol/l--it provides normal calcium metabolism. Issues that are discussed include the vitamin D serum concentration needed to suppress the aberrant immune response in MS patients; a subgroup of MS patients suitable for vitamin D treatment, the vitamin D being applied in optimally effective and safe dosage. MS prevalence rate in Bulgaria has increased two-fold in 17 years but this is a rather short interval to be able to assume that the gene pool of the population changes. Thus further studies on possible interactions between different environmental factors and these factors' role in the disease pathogenesis are justified and necessary.

Clinical and laboratory study of pro-inflammatory and antiinflammatory cytokines in women with multiple sclerosis.

UNLABELLED: Multiple sclerosis (MS) is an autoimmune demyelinating disorder of the central nervous system characterised with a complex system of interactions between proinflammatory and anti-inflammatory cytokines in its course. AIM: The aim of the present study was to investigate the serum levels of cytokines TNF-a, IFN-gamma, IL-4 and IL-10 in female patients with MS and healthy individuals, the changes occurring in the relapse and remission phases of the disease and their correlation with the severity of the neurological deficit. PATIENTS AND METHODS: Thirty-five women with relapsing-remitting MS were examined. The patients' age ranged between 18 and 50 years and MS was verified clinically and by magnetic resonance imaging according to the McDonald criteria. Thirteen of the patients were treated with interferon-beta-1b. The serum concentrations of TNF-a, IFN-y, IL-4 and IL-10 were determined twice - in relapse and in remission - using an enzyme-linked immunosorbent assay (ELISA). The control group consisted of 35 age-matched healthy females. RESULTS: The comparison of cytokine serum concentrations during the two phases of the disease showed significant elevation of the TNF-alpha serum levels in the relapse phase and of IL-4 - in the remission phase. The comparison between the patients and the healthy control subjects demonstrated statistically significant lower concentrations of TNF-a in remission patients and higher concentrations of IL-10 in relapse patients. The patients with interferon-beta-lb treatment showed different profile of cytokine secretion from the patients without interferon-beta-1b treatment. Interferon-beta-1b-treated patients showed significantly lower serum levels of TNF-a and IFN-gamma during the relapse phase and higher TNF-a and IL-10 serum levels during the remission phase compared with the untreated patients. CONCLUSIONS: Serum levels of TNF-a and IL-4 objectively reflect the immune response during relapse and remission of the disease. The severity of neurological deficit as estimated with the expanded disability status scale (EDSS) does not depend on the serum levels of TNF-a, IL-10 and IFN-gamma in the two phases of MS.

Association of polymorphism -308G/A in tumor necrosis factor-alpha gene (TNF-α) and TNF-α serum levels in patients with relapsing-remitting multiple sclerosis.

TNF-α is an important cytokine of the inflammatory response involved in the pathogenesis of relapsing-remitting multiple sclerosis (RRMS). The aim of this study is to explore the association between the promoter polymorphism -308G/A in the TNF-α gene (rs1800629) with genetic susceptibility to RRMS.Methods: A group of 183 RRMS patients and 169 age and gender-matched healthy controls were enrolled in the study. Genotyping of the polymorphism was performed by PCR-restriction fragment length polymorphism and quantification of TNF-α serum levels was conducted by ELISA.Results: The genotype distribution in female patients showed a significantly elevated frequency of heterozygotes (AG) (23.5% vs. 12.8%, OR = 2.072, p = 0.029) in comparison with the healthy women. Substantially higher TNF-α serum levels were observed in females compared to males, in both patients and healthy controls (p < 0.05). According to the genotype, TNF-α levels in the RRMS group were calculated in the following order: for GA/AA genotypes (5.67pg/ml vs. 3.48pg/ml, p = 0.0031) and for GG genotypes (4.58pg/ml vs. 3.52pg/ml, p = 0.00043). Moreover, the carriers of at least one A-allele of -308G/A TNF-α polymorphism (GA+AA) are significantly associated with two fold increased risk for RRMS development (OR = 1.950; p = 0.042) in women in contrast to men as well as associated with early onset of the disease (OR = 2.400; p = 0.021).Conclusion: Our study showed that the level of TNF-α in the serum of patients with RRMS showed a significant association with the -308G/A TNF-α polymorphism and gender dependency.

Translational validity of PASAT and the effect of fatigue and mood in patients with relapsing remitting MS: A functional MRI study.

RATIONALE, AIMS, AND OBJECTIVES: Paced Auditory Serial Addition Test (PASAT) is used for assessment of information processing speed, attention, and working memory, which are the most frequently affected cognitive domains in multiple sclerosis (MS) patients, and may be significantly affected by fatigue. However, the effect of fatigue and mood on the PASAT performance in MS patients translationally validated by fMRI has not been studied yet. The aim of this study is to investigate the translational validity of the PASAT, using fMRI during a paced visual serial addition test (PVSAT) paradigm in patients with relapsing remitting MS (RRMS) and to assess the impact of fatigue and mood on test performance. METHODS: Fourteen patients with RRMS in remission and 14 healthy controls, matched by sex, age, and educational status, were enrolled in the study. The subjects underwent a standard neurological examination, neuropsychological evaluation with the PASAT 3', fMRI scanning with a PVSAT paradigm, and Beck Depression Inventory. All patients were assessed by the Modified Fatigue Impact Scale. RESULTS: Paced Auditory Serial Addition Test score was lower in patients (41.4 ± 15.5 vs 51.6 ± 7.5, P = .035). A moderate negative correlation (P = -0.563, P = 0.036) was found between PASAT and MIFS scores. The fMRI scanning showed significant activations in several clusters that differed between patients and controls. The patient group presented wider cluster activation; Brodmann area (BA) 6-bilaterally; left BA7, 8, and 9; and right BA40, while controls presented with activations in left BA6 and BA44. Significant negative correlations between PASAT score and cortical activations in left BA23, right BA32, and left BA7 were observed in patients only. CONCLUSION: Our results show that poorer performance on the PASAT is associated with higher activation in areas connected with working memory, attention, and emotional processes during the fMRI assessment with PVSAT paradigm, which provides evidence for the translational validity of the PASAT in patients with RRMS.

Circulating levels of interleukin-17A, tumor necrosis factor-alpha, interleukin-18, interleukin-10, and cognitive performance of patients with relapsing-remitting multiple sclerosis.

Multiple sclerosis (MS) is associated with cytokine imbalance and high rate (40-70%) of cognitive impairment. The objective of this study is to investigate the relationship between serum concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-17A, IL-18, IL-10, and cognitive performance in patients with relapsing-remitting MS (RRMS). Methods The study comprised 159 patients with RRMS (mean age 40.08 ± 8.48 years) in remission phase and 86 age-, gender-, and education-matched healthy controls. Paced Auditory Serial Addition Test (PASAT), Symbol Digit Modalities test (SDMT), and Isaacs test were used for assessment of working memory, attention, visuo-perceptual abilities, information processing speed, and executive functions. Serum cytokine concentrations were measured by enzyme-linked immunosorbent assay (ELISA). Results Patients had significantly increased serum concentrations of TNF-alpha and IL-17A and decreased levels of IL-10 compared to the controls (p < 0.05). Negative correlation was found between serum TNF-alpha and SDMT score in patients with disease evolution longer than 10 years (rxy = -0.258 p = 0.033); PASAT and SDMT scores were in negative correlation with concentration of IL-17A (rxy = -0.229 p = 0.004; rxy = -0.166 p = 0.041). Cognitive impairment was established in 46.5% (n = 74) of the patients. Cognitively impaired patients had significantly higher serum IL-17A than cognitively preserved individuals (p = 0.007). Multiple linear regression analysis revealed IL-17A as a significant predictor of cognitive performance in RRMS patients. Conclusion The results from this study suggest that pro-inflammatory cytokines IL-17A and TNF-alpha simultaneously with decreased IL-10 are involved in cognitive deterioration in RRMS.

Cytokines and disability in interferon-ß-1b treated and untreated women with multiple sclerosis.

BACKGROUND AND AIMS: T-helper (Th) cells involved in the pathogenesis of multiple sclerosis (MS) represent a functionally heterogeneous population defined by their cytokine secretion profile. The effects of immunotherapeutic drugs on the cytokine network are still not fully clarified. This study aimed to investigate serum levels of IFN-γ, TNF-α, IL-4, IL-10 in interferon-ß-1b-treated and untreated women with relapsing-remitting MS (RRMS) in comparison with healthy controls and the relationship between cytokine concentrations and the degree of disability. METHODS: The study included 35 women with RRMS and 35 age-matched healthy controls. The patients were divided in two groups: Group A-without disease modifying treatment; Group B-treated with interferon-ß-1b. Degree of disability was assessed by the Expanded Disability Status Scale (EDSS). Serum cytokine concentrations were measured by ELISA during relapse and remission. RESULTS: Group A showed higher IFN-γ in remission (p = 0.0239) than the controls; Group B had lower IFN-γ during relapse (p = 0.0226) than controls. EDSS in relapse correlated with the levels of IL-10 for Group A (p = 0.015) and with the concentration of IFN-γ for Group B (p = 0.039). Nontreated patients showed higher EDSS in relapse compared to the interferon-ß-1b-treated group (p = 0.005). CONCLUSIONS: We found an imbalance in the patients' cytokine profile, which may be seen as supportive of the hypothesis that demyelination in the central nervous system is mediated by Th1 lymphocytes. IFN-γ is probably one of the important indicators for intensity of the immune reaction and shows promise as a potential biomarker for the therapeutic effect of interferon-ß-1b. The role of IL-10 in the autoimmune process needs further investigation.

Female sex hormones and cytokine secretion in women with multiple sclerosis.

UNLABELLED: Data from experimental and clinical research suggest that sex hormones may influence the autoimmune process in multiple sclerosis (MS). Studies on the hormonal profile of patients with MS and its relation to the disease activity provide heterogeneous results. OBJECTIVES: The aim of this study is to investigate the changes in serum levels of estradiol and progesterone and their correlations with the cytokine profile and the degree of disability in women with relapsing-remitting MS (RRMS). METHODS: The serum concentrations of estradiol, progesterone, tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), interleukine-4 (IL-4) and interleukine-10 (IL-10) were measured and the degree of disability was determined in 35 women with RRMS, during relapse and remission. Serum levels of hormones were measured by micro-particle enzyme immunoassay and ELISA was used for the cytokines concentrations. The degree of disability was assessed by the Expanded Disability Status Scale and the Scripps Neurological Rating Scale. RESULTS: Sixty per cent of patients had serum concentrations of estradiol and/or progesterone below the lower limit of normal in one or both phases of MS. Hormonal levels increased significantly during remission in these patients. Women with and without hormonal abnormalities differed in terms of cytokine profile during relapse and remission. Significantly higher TNF-alpha in both phases and IFN-gamma in remission was found for the patients with hormonal disturbances compared to these with normal hormonal status. CONCLUSIONS: Our study finds high frequency of hormonal disturbances among female patients with RRMS. Abnormally low concentrations of sex hormones are associated with higher serum levels of TNF-alpha and IFN-gamma, which could suggest suppressive effect of estradiol and progesterone on pro-inflammatory cytokine secretion.