Disturbed sleep and atherosclerosis

Summary Atherosclerosis is the major etiological process responsible for 25% of global deaths. Numerous reports indicate both the adaptive and innate immune systems are involved in atherogenesis. In addition to well- established risk factors such as age, hypertension, high circulating levels of low-density lipoprotein cholesterol,

and type 2 diabetes, the quality and quantity of sleep are now recognized as important factors for atherogenesis. Sleep is vital for life. In the USA, ~70 million people report insufficient sleep and/or fragmented sleep due to work responsibilities, sleep apnea, caregiving, and lifestyle choices. Changes in sleep are a part

of the normal aging process, leading to increased sleep fragmentation (SF), nighttime awakenings, and a greater tendency for daytime sleep. Dysregulation of normal sleep negatively affects homeostatic functions and is associated with an increased risk of chronic diseases, including atherosclerosis. Long-term SF may lead to

endothelial dysfunction, oxidative stress, and altered vessel wall structure. SF has a negative impact on atherogenesis through the regulation of myelopoiesis, highlighting the complex relationship between sleep, the vascular system, and the immune system. One of the remaining outstanding questions in the field is the extent

to which SF affects the vulnerability of plaques. Another important question that remains to be investigated is whether the restoration of sleep quality might reduce atherosclerosis development and improve the phenotype of the plaques. Our results indicate that SF supports neutrophil functions such as ROS and NET production. We detect

increased circulating levels of LPS that might serve as a neutrophil activator during SF. Competitive homing experiments clearly demonstrated that SF directs neutrophil recruitment into the aorta. Importantly, neutrophil depletion improves plaque phenotype of SF mice. One of the strongest phenotypes observed in the circulation

and the gut was a significant degree of oxidative stress, cell death, and neutrophil activation. Gut inflammation was also supported by alterations in the intestinal immune composition. In this application, we propose the hypothesis that disturbed sleep negatively influences gut-associated inflammation, triggering LPS-induced

oxidative stress, and activating neutrophils, which, in turn, plays a key role in the formation of accelerated vulnerable plaques. Here, we propose to investigate the role of NADPH-dependent oxidative stress in vulnerable atherosclerotic plaque formation in response to SF in HFD-fed via neutrophil or intestinal epithelial

cell-specific NADPH-deficient Apoe-/- mice (Aim 1). In Aim 2, we will test to what extent restoring sleep quality would improve the phenotype of atherosclerotic plaques and reduce atherogenesis. The findings from this proposal could lead to the development of new treatments aimed at preventing gut-associated and neutrophil-

induced oxidative stress and suppressing accelerated atherogenesis induced by SF.