Fecal microbiota transplantation from mice exposed to chronic intermittent hypoxia elicits sleep disturbances in naïve mice

Abstract

Obstructive sleep apnea (OSA) is a chronic prevalent condition characterized by intermittent hypoxia (IH) and sleep fragmentation (SF). Evidence suggests that OSA can alter the gut microbiome (GM) diversity and composition that may then promote the occurrence of some of the OSA-associated morbidities. However, it is unclear whether perturbations in the GM caused by IH can elicit sleep disturbances that underlie the increased sleep propensity that occurs in IH-exposed mice. To evaluate this issue, we exposed C57Bl/6 J mice to IH or room air (RA) for 6 weeks, and fecal matter was collected and frozen. C57Bl/6 J naïve mice were then randomly assigned to a fecal microbiota transfer (FMT) protocol for 3 weeks with either IH or RA fecal slur, and their GM was then analyzed using 16 s rRNA sequencing. In addition, FMT recipients underwent sleep recordings using piezoelectric approaches for 3 consecutive days. As anticipated, FMT-IH and FMT-RA mice showed different taxonomic profiles that corresponded to previous effects of IH on GM. Furthermore, FMT-IH mice exhibited increased sleep duration and the frequency of longer sleep bouts during the dark cycle, suggesting increased sleepiness (p < 0.0001 vs. FMT-RA mice). Thus, alterations of GM diversity induced by IH exposures can elicit sleep disturbances in the absence of concurrent IH, suggesting that sleep disturbances can be mediated, at least in part, by IH-induced alterations in GM.

Keywords: Fecal matter transfer; Gut microbiome; Intermittent hypoxia; Sleep; Sleep apnea.

Figure 1:

Alterations in fecal bacterial composition between FMT-IH and FMT-IA. A) principal coordinate analysis plot ordinated using Jaccard similarities. B) Stacked bar chart showing the mean relative abundance of bacterial taxa, C) Volcano plot showing fold difference (FD, x-axis) and p-value (Y-axis) associated with taxa detected at significantly greater relative abundance in FMT-IH (left) and FMT-RA (right), D) Hierarchical cluster analysis of the 50 consistently detected OTUs in the gut microbiota. FMT: fecal microbiota transplantation, IH: intermittent hypoxia, RA: room air, OUT: operational taxonomic unit

Figure 2:

Changes in sleep patterns between FMT-IH and FMT-RA. A) Representative sleep-wake profiles of FMT-IH and FMT-IA groups over 3 days. B) Quantification of total, light-phase and dark-phase average wake percentages. Groups were compared using Student’s t test (n=7–8). *p < 0.05, ** p < 0.01, ***p < 0.001, ****p < 0.0001.

Figure 3:

Changes is sleep bout lengths and numbers in FMT-IH and FMT-IA. A) Quantification of total, light-phase and dark-phase average sleep bouts. Groups were compared using Student’s t test (n=7–8). (B-C) sleep percent of average sleep bout lengths during the light-phase (B) and dark-phase (C). (D-F) number of sleep bouts lengths across in total (D), light-phase (E) and dark-phase (F). Groups were compared using Two-way ANOVA with repeated measurement with Sidak post hoc test (n=7–8). *p < 0.05, ** p < 0.01, ***p < 0.001, ****p < 0.0001.