Gut Dysbiosis and Enterotypes Distribution in Different Degrees of Patients with Obstructive Sleep Apnea-Hypopnea Syndrome

Abstract

Background: Mimicking obstructive sleep apnoea-hypopnea syndrome (OSAHS), gut microbiota alterations manifest in intermittent hypoxia and fragmented sleep. However, no direct survey of gut microbial dysbiosis over a range of apnoea-hypopnea index (AHI) of OSAHS cases existed, thus that is our aims in this work. Methods: We obtained faecal samples of 93 OSAHS patients [5≺AHI≤15 (n=40), 15≺AHI≤30 (n=23) and AHI≥30 (n=30)] and 20 controls (AHI≤5) and determined the microbiome composition by variable regions 3-4 of the 16S rRNA pyrosequencing and bioinformatic analyses. We examined the fasting levels of homocysteine (HCY), interleukin-6 and tumor necrosis factor alpha of all subjects. Findings: We identified the gut microbial dysbiosis of differing severities in several OSAHS patients, reliably separating the OSAHS from the control with a ROC-AUC of 0.789. A functional analysis alteration in microbiomes of patients identified, in particular, decreases in shortchain fatty acid (SCFA)-producing bacteria, accompanying with interleukin-6 elevation. Lactobacillus was correlated with HCY level. Additionally, stratification analysis revealed the Ruminococcus enterotype as posing the highest risk for OSAHS. Interpretation: Our results provided that the presence of an altered microbiome among different degrees of OSAHS patients is associated with HCY. The speculated changes in SCFA generating reduction and pathogens elevation apparently have a pathophysiological role in OSAHS and its related metabolic comorbidities. Funding: None. Declaration of Interest: The authors declare that they have no financial and personal relationships with others that may inappropriately influence the results and interpretation in this manuscript. Ethical Approval: The Institutional Review Board of the Second Affiliated Hospital of Fujian Medical University approved this study (IRB No. 2017-78).