[Preliminary analysis of intestinal microflora in patients with different severity of OSAHS]

Objective: To analyze the diversity, abundance and structural composition of intestinal microflora in patients with different severity of OSAHS, and to explore their potential role in the occurrence and development of OSAHS. Methods: A total of 27 healthy volunteers(N) [male 19, female 8, age 22-78(44.4±2.7)years old] of Health Examination Center of the Second Hospital of Shanxi Medical University and 100 patients with OSAHS [male 86, female 14, age 19-78(49.1±1.3) years old] of Sleep Medicine Center of the Second Hospital of Shanxi Medical University were enrolled from December 2018 to September 2019, and patient-related sleep monitoring data and medical history data were collected.According to the AHI classification and whether there were complications, OSAHS patients were divided into mild group (L), moderate group (M), severe group (S) and severe complication group (SC).Using 16S rRNA high-throughput sequencing technology to analyze the intestinal flora of all people, bioinformatics related statistics were analyzed by QIIME2 software, and clinical data were analyzed by SPSS 25.0 software. Results: There was no significant difference in intestinal flora Alpha and Beta diversity among all groups (P>0.05). At phylum level, the relative abundance of Bacteroides in OSAHS group was lower than that in normal group (N group: 24.96%, L group: 18.31%, M group: 12.95%, S group: 15.78%, Sc group: 16.48%). At genus level, the relative abundance of Bacteroides (N group:16.03%, L group: 10.82%, M group: 9.79%, S group: 9.29%, Sc group: 8.25%) and Faecalibacterium (N group: 11.21%, L group: 10.42%, M group: 10.21%, S group: 8.54%, Sc group: 6.27%) were negatively correlated with the severity of OSAHS (the values of r respectively were -0.887, -0.945) while the relative abundance of Bifidobacterium (N group: 3.20%, L group: 2.47%, M group: 4.10%, S group: 4.93%, Sc group: 6.27%) and Blautia (N group: 2.52%, L group: 3.59%, M group: 3.81%, S group: 4.11%, Sc group: 5.86%) were positively correlated with the severity of OSAHS (the values of r respectively were 0.916, 0.940) Compared with the S group, the relative abundance of Roseburia (S group: 10.22%, Sc group: 6.65%) in the Sc is lower and the relative abundance of Shigella(S group: 4.64%, Sc group: 10.01%) is higher. Redundancy analysis (RDA) showed that Apnea hypopnea index (AHI), The lowest oxygen saturation (SpO₂min), The average saturation of blood oxygen (SpO₂mean) and The longest time of apnea (Tmax) were not significantly correlated with the overall abundance of intestinal flora (P>0.05), However, there was a significant correlation between the abundance of different flora and sleep monitoring indicators. Conclusion: There is an intestinal microecological imbalance in patients with OSAHS, mainly due to the reduction of the relative abundance of probiotics producing short-chain fatty acids and the increase of pathogenic bacteria, suggesting that the disturbance of intestinal flora may be related to the occurrence and development of OSAHS.