Investigation of anti-neuronal antibodies and disparity in central hypersomnias.

STUDY OBJECTIVES: Microbial antigens can elicit an immune response leading to the production of autoantibodies cross-reacting with autoantigens. Still, their clinical significance in human sera in the context of brain diseases is unclear. Therefore, assessment of natural autoantibodies reacting with their neuropeptides may elucidate the autoimmune etiology of central hypersomnias. The study aims to determine whether serum autoantibody levels differ in patients with different types of central hypersomnias (narcolepsy type 1 and 2, NT1 and NT2; idiopathic hypersomnia, IH) and healthy controls and if the differences could suggest the participation of autoantibodies in disease pathogenesis. METHODS: Sera from 91 patients with NT1, 27 with NT2, 46 with IH, and 50 healthy controls were examined for autoantibodies against assorted neuropeptides. Participants were screened using questionnaires related to sleep disorders, quality of life, and mental health conditions. In addition, serum biochemical parameters and biomarkers of microbial penetration through the intestinal wall were determined. RESULTS: A higher prevalence of autoantibodies against neuropeptides was observed only for alpha-melanocytes-stimulating hormone (α-MSH) and neuropeptide glutamic acid-isoleucine (NEI), which differed slightly among diagnoses. Patients with both types of narcolepsy exhibited signs of microbial translocation through the gut barrier. According to the questionnaires, patients diagnosed with NT2 or IH had subjectively worse life quality than patients with NT1. Patients displayed significantly lower levels of bilirubin and creatinine and slightly higher alkaline phosphatase values than healthy controls. CONCLUSIONS: Overall, serum anti-neuronal antibodies prevalence is rare, suggesting that their participation in the pathophysiology of concerned sleep disorders is insignificant. Moreover, their levels vary slightly between diagnoses indicating no major diagnostic significance.

Guardians of Rest? Investigating the gut microbiota in central hypersomnolence disorders.

In recent years, there has been an increased interest in elucidating the influence of the gut microbiota on sleep physiology. The gut microbiota affects the central nervous system by modulating neuronal pathways through the neuroendocrine and immune system, the hypothalamus-pituitary-adrenal axis, and various metabolic pathways. The gut microbiota can also influence circadian rhythms. In this study, we observed the gut microbiota composition of patients suffering from narcolepsy type 1, narcolepsy type 2, and idiopathic hypersomnia. We did not observe any changes in the alpha diversity of the gut microbiota among patient groups and healthy controls. We observed changes in beta diversity in accordance with Jaccard dissimilarities between the control group and groups of patients suffering from narcolepsy type 1 and idiopathic hypersomnia. Our results indicate that both these patient groups differ from controls relative to the presence of rare bacterial taxa. However, after adjustment for various confounding factors such as BMI, age, and gender, there were no statistical differences among the groups. This indicates that the divergence in beta diversity in the narcolepsy type 1 and idiopathic hypersomnia groups did not arise due to sleep disturbances. This study implies that using metabolomics and proteomics approaches to study the role of microbiota in sleep disorders might prove beneficial.

Sleep disorders after COVID-19 in Czech population: Post-lockdown national online survey.

Objective: This study aimed to determine the frequency, type, and correlates of a broad spectrum of sleep disorders in adults with COVID-19 up to 32 months after infection. Methods: We conducted a national online survey (Jun 2021-Dec 2022), gathering information on COVID-19 diagnosis, acute disease course, and the subsequent development of sleep disorders from 1507 respondents (mean age 44.5 ± 13.1 years, 64.1% women). Results: 81.3% (1223) reported at least one sleep difficulty that either worsened or first appeared with COVID-19. Females reported a higher number of symptoms (2.03 ± 1.44 versus 1.72 ± 1.43 in men, p < 0.0001). Most common were insomnia symptoms (59.4%), followed by night sweats (38.4%), hypersomnolence (33.3%), vivid dreams or nightmares (26.4%), restless leg syndrome (RLS) (22.8%), and sleep-related breathing disorders (11.1%). All symptoms were associated with a more severe acute disease. A mild decreasing trend in the persistence of sleep symptoms with a longer latency since infection was observed, with 66.7% reporting at least half of their symptoms present at 3-5 months after acute infection, compared to 64.9% at 6-8 months, and 62.4% at 9-11 months (p = 0.0427). However, among those after 12 or more months, over half of the symptoms persisted in 69.5%. The frequency of vivid dreams and nightmares increased in association with COVID-19 in 32.9% (p < 0.001). 9.4% (141) reported new-onset or increased parasomnic manifestations after the infection. Conclusions: Our research shows that sleep disturbances are a common and persistent manifestation of COVID-19 that affects a large proportion of the population and deserves careful monitoring.