Sleep disorders in patients with multiple sclerosis.

OBJECTIVE: Poor sleep is a frequent symptom in patients with multiple sclerosis (MS). The objective of the study was to assess the relationship between nocturnal polysomnographic (PSG) findings and quality of sleep, fatigue, and increased daytime sleepiness among patients with MS. METHODS: Clinical characteristics were collected. Pittsburgh Sleep Quality Index (PSQI), Fatigue Severity Scale (FSS), Epworth Sleepiness Scale (ESS), and International Restless Legs Syndrome Rating Scale were used to assess quality of sleep, fatigue, excessive daytime sleepiness, and the presence of restless legs syndrome (RLS). All patients underwent nocturnal diagnostic PSG examination. RESULTS: Fifty patients with MS were enrolled into the study. Age was the only independent variable significantly determining apnea-hypopnea index and desaturation index (DI) (beta = 0.369, p = 0.010, beta 0.301, p = 0.040). PSQI and ESS score were significantly higher in a population with RLS (p = 0.004, p = 0.011). FSS significantly correlated with DI (r = 0.400, p = 0.048). Presence of RLS was the only independent variable significantly determining PSQI and ESS (p = 0.005, p = 0.025). DI and presence of RLS were independent variables determining FSS (p = 0.015, p = 0.024). CONCLUSION: Presence of RLS seems to be the main factor determining poor sleep, fatigue, and daytime somnolence. Sleep disordered breathing and its severity influences only fatigue in patients with MS.

Markers of oxidative stress in plasma and saliva in patients with multiple sclerosis.

BACKROUND: Oxidative stress plays a role in multiple sclerosis. Saliva can be potentially used to study the disease progression or treatment, because of its non-invasiveness and easy collection. But studies on saliva and multiple sclerosis are missing. The aim of this study was to compare the concentrations of salivary oxidative stress markers in patients and healthy controls. OBJECTIVE: Whole saliva and blood samples were collected from 29 patients and 29 healthy controls. Samples were collected during relapse, after corticosteroid therapy, and after three months. Markers of oxidative, carbonyl stress and antioxidant status were measured. RESULTS: In plasma, thiobarbituric acid reacting substances, advanced oxidation protein products and fructosamine were significantly higher in patients compared to controls (by 271%, 46% and 24%, respectively; p<0.01). Total antioxidant capacity in plasma was lower by 20% (p<0.01) in patients versus controls. In saliva, higher levels of thiobarbituric acid reacting substances and advanced glycation end-products were observed in patients when compared to controls (by 51% and 49% respectively; p<0.01). Ferric reducing ability was reduced by 38% (p<0.05) in patients with multiple sclerosis. CONCLUSION: According to our knowledge, this is the first report showing higher markers of oxidative stress and lower antioxidant status in patients with multiple sclerosis in saliva.

Predictors of impaired endothelial function in obstructive sleep apnea syndrome.

OBJECTIVES: Obstructive sleep apnea syndrome (OSA) is associated with increased cardiovascular morbidity and mortality. Endothelial dysfunction (ED), accelerated atherosclerosis and autonomic dysfunction might be the key players responsible for development of vascular diseases in patients with OSA. In a population with suspected OSA and low burden of cardiovascular risk factors, we therefore aimed to investigate the association between potential cardiovascular risk factors including OSA-specific indices, ED and autonomic activity. METHODS: ED was investigated using reperfusion hyperaemia index (RHI). OSA was assessed using standard polysomnography, autonomic activity was assessed using baroreflex sensitivity (BRS). RESULTS: We enrolled 31 patients (42.1±11.7 years) with OSA. Significant inverse correlation was found between RHI and apnea-hypopnea index (AHI) (r=-0.550, p=0.001) and between RHI desaturation index (r=-0.533, p=0.002). Positive correlation was found between RHI and minimal nocturnal oxygen saturation (r=0.394, p=0.028). In a multiple regression model AHI was the only significant variable to predict RHI (ß=-0.522, p=0.003). We found no correlation between RHI and BRS. RHI in the population with severe OSA (AHI above 30) was significantly lower than RHI in the rest of the population (p=0.012). CONCLUSION: AHI was the only significant independent predictor of impaired endothelial function as expressed by RHI. RHI showed no association with BRS in patients with OSA.

Genetic aspects of vitamin D receptor and metabolism in relation to the risk of multiple sclerosis.

Recent findings suggest that polymorphisms in vitamin D pathway genes are candidates for association with multiple sclerosis susceptibility. It has been now well demonstrated that vitamin D has immunomodulatory functions that may be favorable for reduction of multiple sclerosis risk. Current research has been focused on identification of new variants of genes involved in vitamin D pathway, namely in vitamin D receptor and enzymes of vitamin D metabolism. These variants have been intensively studied as possible genetic predictors of both vitamin D levels and the risk of multiple sclerosis. Considering the findings available up-to-date, we may recognize two groups of genetic variants. The first group of genes was found to predict vitamin D levels but not the risk of multiple sclerosis. The second group of genetic variants is represented by promising genes predicting vitamin D levels as well as the risk of multiple sclerosis. A strong association with increased risk of the disease has been observed for a rare variant in the CYP27B1 gene encoding a vitamin D-activating enzyme. Observed interaction between genetic and epidemiological findings brings the rationale for supplementation trials of vitamin D. Although promising effects of vitamin D supplementation have emerged, the results obtained so far are inconclusive and the real therapeutic significance of vitamin D supplementation remains to be elucidated.

Vasovagal (neurocardiogenic) syncope in the clinical practice.

OBJECTIVES: Vasovagal syncope (VVS) is the most common type of syncope with the incidence of 21-43%. The aim of this study was to explain difficulties of correct diagnosis of VVS. DESIGN AND METHODS: Our group comprises 70 patients (24 men, 46 women) at the age of 15-71 years, in whom VVS was verified by the head-up tilt test (HUT-test). We evaluated the type of VVS, admission diagnoses present in the patients, interictal EEG findings and the presence of convulsions during the syncopal states. For statistical processing of the results we used binomial tests for two independent proportions, Fisher-Freeman-Haltons exact test and Cramér's V index. RESULTS: Out of 70 VVS 35 were vasodepressoric, 19 cardioinhibitive and 16 intermediate. Admission diagnoses present in the patients were: disorders of consciousness of an unknown etiology - 42.9% cases; supposable epilepsy and epilepsy - 30% cases and syncope - 27.1% cases. Interictal EEG was normal in 51.4% cases, nonepileptiform abnormality was present in 48.6% cases. Statistical comparison among particular types of VVS revealed a significant difference in distribution and medial strong association between the type of VVS and the EEG finding (Cramér V=0.35) and also between the type of VVS and the occurrence of convulsions (Cramér V= 0.40). CONCLUSION: The results of our study evidently suggest that interdisciplinary cooperation in accurate diagnostics in this field of medicine is needed and that HUT-test has to be in standard diagnostic algorithm in patients with failures of consciousness of an unknown cause.