Cardioprotective Microbes And Restorative Sleep Are Reduced And Blood Pressure During Sleep Is Increased When Rats Have Fragmented Sleep

Introduction: Sleep that is restless and fragmented impairs cardiovascular (CV) health. Using a rat model, we measured sleep characteristics and assessed bacterial communities in the gut microbiome. We hypothesized poor quality sleep to be associated with a reduction in cardioprotective microbiomes and adverse CV outcomes. Methods: Wistar Kyoto rats had normal sleep (n= 7, controls) or 8-hrs of fragmented sleep (n = 8) for 28 days. Implanted telemetry transmitters recorded blood pressure (BP), heart rate (HR), and cortical electroencephalogram (EEG) signals continuously. Fecal samples were collected daily; microbial composition was determined by 16S rRNA amplicon sequencing. Results: The sleep fragmented (SF) rats could not achieve deep slow-wave sleep (SWS) for 8-hrs each day—compared with controls, relative EEG delta power (a marker of the depth of sleep) was significantly lower (29±3% versus 39±3%, P = 0.04). In addition, SF was associated with a rise in BP and HR. The relative abundance of Parabacteroides (classified to genus level) and Tannerellaceae (classified to family level), both gram-negative anaerobic bacteria from the phylum Bacteroidetes, were decreased in SF rats during late-SF (intervention days 20 & 27), relative to controls. Elevated Parabacteroides levels (%) were significantly and inversely correlated with systolic (R= -0.002, P <0.001) and diastolic (R= -0.003, P <0.001) BP levels recorded during sleep in both groups of rats. Conclusions: Parabacteroides levels in the gut microbiome may contribute to changes in BP. Undesirable changes in sleep from SF are associated with reduced levels of Parabacteroides during the late-SF period in the gut microbiome, compared with controls. The Parabacteroides -BP associations and reactivity of this bacterium to disrupted sleep support Parabacteroides as an exciting cardioprotective biomarker to stratify and prevent negative CV outcomes provoked by SF.