Gut Microbiota in Patients with Type 1 Narcolepsy

Alternations in the human skin, gut and vaginal microbiomes in perimenopausal or postmenopausal Vulvar lichen sclerosus

Vulvar lichen sclerosus (VLS) is a chronic and progressive dermatologic condition that can cause physical dysfunction, disfigurement, and impaired quality of life. However, the etiology of VLS remains unknown. The vulvar skin, intestinal and vaginal microbiomes have been postulated to play important roles in the pathogenesis of this disease. The aim of this study was to compare the compositional characteristics of the vulvar skin, vagina, and gut microbiota between perimenopausal or postmenopausal VLS patients and healthy controls. The study involved six perimenopausal or postmenopausal VLS patients which were based on characteristic clinical manifestations and histologic confirmation and five healthy controls. The pruritus severity of each patient was evaluated using the NRS scale, and the dermatology-specific health-related quality of life was assessed using the Skindex-16. Metagenomic sequencing was performed, and the results were analyzed for alpha and beta diversity. LEfSe analysis were used to investigate the microbial alterations in vulvar skin, gut and vagina. KEGG databases were used to analyze differences in functional abundance. The study found significant differences in alpha diversity between the two groups in stool and vaginal samples (P < 0.05). Patients with VLS had a higher abundance of Enterobacter cloacae, Flavobacterium_branchiophilum, Mediterranea_sp._An20, Parabacteroides_johnsoniiand Streptococcus_bovimastitidis on the vulvar skin, while Corynebacterium_sp._zg-913 was less abundant compared to the control group. The relative abundance of Sphingomonas_sp._SCN_67_18, Sphingobium_sp._Ant17, and Pontibacter_sp_BT213 was significantly higher in the gut samples of patients with VLS.Paenibacillus_popilliae,Gemella_asaccharolytica, and Coriobacteriales_bacterium_DNF00809 compared to the control group. Additionally, the vaginal samples of patients with VLS exhibited a significantly lower relative abundance of Bacteroidales_bacterium_43_8, Bacteroides_sp._CAG:20, Blautia_sp._AM28-10, Fibrobacter_sp._UWB16, Lachnospiraceae_bacterium_AM25-39, Holdemania_filiformis, Lachnospiraceae_bacterium_GAM79, and Tolumonas_sp. Additionally, the butyrate-producing bacterium SS3/4 showed a significant difference compared to the controls. The study found a negative relationship between Sphingobium_sp._Ant17 in stool and Skindex-16 (P < 0.05), while Mediterranea_sp._An20 had a positive correlation with Skindex-16 (P < 0.05) in the skin. Additionally, our functional analysis revealed alterations in Aminoacyl_tRNA_biosynthesis, Glutathione_metabolism, the pentose phosphate pathway, and Alanine__aspartate_and_glutamate_metabolism in the VLS patient group. The study suggests that perimenopausal or postmenopausal patients with VLS have a modified microbiome in the vulvar skin, gut, and vagina. This modification is linked to abnormal energy metabolism, increased oxidative stress, and abnormal amino acid metabolism.

Identification of bidirectional causal links between gut microbiota and narcolepsy type 1 using Mendelian randomization

STUDY OBJECTIVES

Narcolepsy type 1 (NT1), characterized by cataplexy and orexin deficiency, is a rare and frequently debilitating neurological disorder. It has been noted to have connections with the gut microbiota, yet the exact causal relationships remain unclear.

METHODS

We conducted a comprehensive bidirectional Mendelian randomization (MR) study to rigorously investigate the causal links between the gut microbiota and NT1, utilizing genetic datasets from the MiBioGen consortium and FinnGen consortium, respectively. The inverse-variance weighted (IVW) method was employed to obtain the primary MR estimates, supplemented by several alternative methods as well as sensitivity analyses including Cochran's Q, MR-Egger, MR pleiotropy residual sum and outlier, leave-one-out, and genetic colocalization.

RESULTS

Our findings indicated that an increased relative abundance of five genera including Blautia (p = 4.47E-5), Collinsella (p = 0.036), Gordonibacter (p = 0.047), Hungatella (p = 0.015), and Lachnospiraceae UCG010 (p = 0.027) may be associated with a decreased risk of NT1. Conversely, an increased relative abundance of class Betaproteobacteria (p = 0.032), genus Alloprevotella (p = 0.009), and genus Ruminiclostridium6 (p = 0.029) may potentially heighten the risk of NT1. The onset of NT1 may lead to a decrease in the relative abundance of genus Eubacterium eligens group (p = 0.022), while a increase in the family Family XI (p = 0.009), genus Hungatella (p = 0.005), genus Prevotella (p = 0.013), and unknown genus id.2001 (p = 0.019). These findings remained robust under all sensitivity analyses.

CONCLUSIONS

Our results offer robust evidence for the bidirectional causal links between particular gut microbial taxa and NT1, underscoring the significance of the microbiota-gut-brain axis in the pathological process of NT1.

Association between sleep-related phenotypes and gut microbiota: a two-sample bidirectional Mendelian randomization study

Background

An increasing body of evidence suggests a profound interrelation between the microbiome and sleep-related concerns. Nevertheless, current observational studies can merely establish their correlation, leaving causality unexplored.

Study objectives

To ascertain whether specific gut microbiota are causally linked to seven sleep-related characteristics and propose potential strategies for insomnia prevention.

Methods

The study employed an extensive dataset of gut microbiota genetic variations from the MiBioGen alliance, encompassing 18,340 individuals. Taxonomic classification was conducted, identifying 131 genera and 196 bacterial taxa for analysis. Sleep-related phenotype (SRP) data were sourced from the IEU OpenGWAS project, covering traits such as insomnia, chronotype, and snoring. Instrumental variables (IVs) were selected based on specific criteria, including locus-wide significance, linkage disequilibrium calculations, and allele frequency thresholds. Statistical methods were employed to explore causal relationships, including inverse variance weighted (IVW), MR-Egger, weighted median, and weighted Mode. Sensitivity analyses, pleiotropy assessments, and Bonferroni corrections ensured result validity. Reverse causality analysis and adherence to STROBE-MR guidelines were conducted to bolster the study's rigor.

Results

Bidirectional Mendelian randomization (MR) analysis reveals a causative interplay between selected gut microbiota and sleep-related phenotypes. Notably, outcomes from the rigorously Bonferroni-corrected examination illuminate profound correlations amid precise compositions of the intestinal microbiome and slumber-associated parameters. Elevated abundance within the taxonomic ranks of class Negativicutes and order Selenomonadales was markedly associated with heightened susceptibility to severe insomnia (OR = 1.03, 95% CI: 1.02-1.05, p = 0.0001). Conversely, the augmented representation of the phylum Lentisphaerae stands in concord with protracted sleep duration (OR = 1.02, 95% CI: 1.01-1.04, p = 0.0005). Furthermore, heightened exposure to the genus Senegalimassilia exhibits the potential to ameliorate the manifestation of snoring symptoms (OR = 0.98, 95% CI: 0.96-0.99, p = 0.0001).

Conclusion

This study has unveiled the causal relationship between gut microbiota and SRPs, bestowing significant latent value upon future endeavors in both foundational research and clinical therapy.

Connecting the dots: An updated review of the role of autoimmunity in narcolepsy and emerging immunotherapeutic approaches

BACKGROUND

Narcolepsy type 1 (NT1) is a chronic disorder characterized by pathological daytime sleepiness and cataplexy due to the disappearance of orexin immunoreactive neurons in the hypothalamus. Genetic and environmental factors point towards a potential role for inflammation and autoimmunity in the pathogenesis of the disease. This study aims to comprehensively review the latest evidence on the autoinflammatory mechanisms and immunomodulatory treatments aimed at suspected autoimmune pathways in NT1.

METHODS

Recent relevant literature in the field of narcolepsy, its autoimmune hypothesis, and purposed immunomodulatory treatments were reviewed.

RESULTS

Narcolepsy is strongly linked to specific HLA alleles and T-cell receptor polymorphisms. Furthermore, animal studies and autopsies have found infiltration of T cells in the hypothalamus, supporting T cell-mediated immunity. However, the role of autoantibodies has yet to be definitively established. Increased risk of NT1 after H1N1 infection and vaccination supports the autoimmune hypothesis, and the potential role of coronavirus disease 2019 and vaccination in triggering autoimmune neurodegeneration is a recent finding. Alterations in cytokine levels, gut microbiota, and microglial activation indicate a potential role for inflammation in the disease's development. Reports of using immunotherapies in NT1 patients are limited and inconsistent. Early treatment with IVIg, corticosteroids, plasmapheresis, and monoclonal antibodies has seldomly shown some potential benefits in some studies.

CONCLUSION

The current body of literature supports that narcolepsy is an autoimmune disorder most likely caused by T-cell involvement. However, the potential for immunomodulatory treatments to reverse the autoinflammatory process remains understudied. Further clinical controlled trials may provide valuable insights into this area.

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.

Microbiota Composition and Probiotics Supplementations on Sleep Quality-A Systematic Review and Meta-Analysis

The gut microbiota (GM) plays a crucial role in human health. The bidirectional interaction between GM and the central nervous system may occur via the microbiota-gut-brain axis, possibly regulating the sleep/wake cycle. Recent reports highlight associations between intestinal dysbiosis and sleep disorders, suggesting that probiotics could ameliorate this condition. However, data are poor and inconsistent. The aim of this quantitative metanalytic study is to assess the GM composition in sleep disturbances and evaluate probiotics' effectiveness for managing sleep disorders. A systematic review was carried out until July 2022 in online databases, limiting the literature research to human studies and English language articles. No significant GM diversity between patients with sleep disturbances versus healthy controls was found, revealed by α-diversity, while β-diversity is missing due to lack of proper reporting. However, probiotics supplementation significantly reduced the self-assessed parameter of sleep quality and disturbances Pittsburgh Sleep Quality Index (PSQI) score compared with the placebo. No difference in the Epworth Sleepiness Scale (ESS) score was found. While available data suggest that GM diversity is not related to sleep disturbances, probiotics administration strongly improves sleep quality as a subjective perception. However, heterogeneity of data reporting in the scientific literature should be considered as a limitation.

Association of ADRB2 gene polymorphisms and intestinal microbiota in Chinese Han adolescents

Gut microbiota are closely related to health, and the β2-adrenergic receptor (ADRB2) gene is associated with gastrointestinal diseases. However, little is known about the relationship between ADRB2 gene polymorphisms and intestinal microbiota. In the present study, we aimed to explore the relationship between ADRB2 gene polymorphisms and gut microbiota in Chinese Han adolescents. Data analysis showed that the relative abundance, PICRUSt function prediction, and Chao1 and ACE indices of gut microbiota were significantly different between males and females (P < 0.05). The rs1042711 was positively associated with the relative abundance of Actinobacteria, Coriobacteriia, Bifidobacteriales, Erysipelotrichi, and Erysipelotrichales. The rs12654778 was negatively associated with Bacilli, Lactobacillales, Bacteroidaceae, and Bacteroides. rs1042713 was positively associated with Lactobacillales and Bifidobacteriales. The rs1042717 was positively associated with Bifidobacteriales and negatively associated with Veillonellaceae. The rs1042719 was negatively associated with Erysipelotrichi and Erysipelotrichales and positively associated with Erysipelotrichi, Erysipelotrichales, Bifidobacteriales, and Ruminococcaceae in females. The rs1801704 was positively associated with Erysipelotrichi, Erysipelotrichales, Bifidobacteriales, Actinobacteria, Coriobacteriia, and Bifidobacteriales. The rs2053044 was positively associated with Ruminococcaceae, Dialister, Firmicutes, Clostridia, Clostridiales, Bifidobacteriales, and Faecalibacterium and negatively associated with Bacilli, Lactobacillales, Lachnospiraceae, and Porphyromonadaceae (P < 0.05). These results suggested that the relative abundance, diversity, and PICRUSt function predictions of male and female gut microbiomes differ significantly and that ADRB2 gene polymorphisms were associated with gut microbiome abundance in Chinese Han adolescents.

The role of gut microbiota in diabetic peripheral neuropathy rats with cognitive dysfunction

Introduction

Owing to advancements in non-invasive magnetic resonance imaging, many studies have repeatedly showed that diabetes affects the central nervous system in the presence of peripheral neuropathy, suggesting a common or interacting pathological mechanism for both complications.

Methods

We aimed to investigate the role of abnormal gut microbiota in rats with diabetic peripheral neuropathy (DPN) combined with cognitive dysfunction. Glucose-compliant rats with nerve conduction deficits were screened as a successful group of DPN rats. The DPN group was then divided into rats with combined cognitive impairment (CD) and rats with normal cognitive function (NCD) based on the results of the Novel object recognition test. Rat feces were then collected for 16S rRNA gene sequencing of the intestinal flora.

Results and Discussion

The results revealed that abnormalities in Firmicutes, Ruminococcaceae, Bacteroidia, and Actinobacteria-like microorganisms may induce DPN complicated by cognitive dysfunction.

New Perspectives on Sleep Regulation by Tea: Harmonizing Pathological Sleep and Energy Balance under Stress

Sleep, a conservative evolutionary behavior of organisms to adapt to changes in the external environment, is divided into natural sleep, in a healthy state, and sickness sleep, which occurs in stressful environments or during illness. Sickness sleep plays an important role in maintaining energy homeostasis under an injury and promoting physical recovery. Tea, a popular phytochemical-rich beverage, has multiple health benefits, including lowering stress and regulating energy metabolism and natural sleep. However, the role of tea in regulating sickness sleep has received little attention. The mechanism underlying tea regulation of sickness sleep and its association with the maintenance of energy homeostasis in injured organisms remains to be elucidated. This review examines the current research on the effect of tea on sleep regulation, focusing on the function of tea in modulating energy homeostasis through sickness sleep, energy metabolism, and damage repair in model organisms. The potential mechanisms underlying tea in regulating sickness sleep are further suggested. Based on the biohomology of sleep regulation, this review provides novel insights into the role of tea in sleep regulation and a new perspective on the potential role of tea in restoring homeostasis from diseases.

Examining Relationships between Sleep Physiology and the Gut Microbiome in Pre-Clinical and Translational Research: A Scoping Review Protocol (Preprint)

Background

Objective

Methods

Results

Conclusions

Trial Registration

International Registered Report Identifier (IRRID)