Intermittent hypoxia due to obstructive sleep apnea has been linked to a higher likelihood of mice developing abdominal aortic aneurysms, as outlined in a recent study.
Researchers at the University of Missouri School of Medicine and NextGen Precision Health suggest that obstructive sleep apnea may contribute to the risk of developing abdominal aortic aneurysms.
Abdominal aortic aneurysms occur when the main blood vessel, the aorta, expands and runs the risk of rupturing, which can lead to dangerous internal bleeding. Obstructive sleep apnea is a long-term condition where individuals experience repeated interruptions in their breathing during sleep, and it can elevate the chances of heart-related issues. Previous studies noted a higher occurrence of abdominal aortic aneurysms in patients with obstructive sleep apnea, prompting researchers from MU to investigate the connection using mouse models.
The research revealed that intermittent hypoxia—when the body is deprived of oxygen for certain intervals—triggered by obstructive sleep apnea heightens the vulnerability of mice to developing abdominal aortic aneurysms.
“Chronic intermittent hypoxia alone won’t directly cause abdominal aortic aneurysms, but for people with obstructive sleep apnea combined with other metabolic issues like obesity, our research implies that it may weaken aortic structures and promote the formation of aneurysms,” explained Luis Martinez-Lemus, a study author and professor of medical pharmacology and physiology.
Intermittent hypoxia occurs during obstructive sleep apnea when muscles in the throat relax and impede airflow into the lungs. The study indicates that this oxygen deficiency activates certain enzymes known as MMPs, which increase in activity and can weaken the extracellular matrix—a supportive structure around cells—thus making the aorta more vulnerable.
“Patients with abdominal aortic aneurysms often don’t exhibit noticeable symptoms, apart from some back and abdominal discomfort, until the aneurysm ruptures. Once that occurs, prompt surgical intervention is vital to repair the aorta,” stated Neekun Sharma, the lead author of the study. “Understanding how these aneurysms form can aid in developing strategies to monitor or slow their progression, particularly for those suffering from obstructive sleep apnea.”
Luis Martinez-Lemus is a professor of medical pharmacology and physiology, holds the James O. Davis Distinguished Professorship in Cardiovascular Research, and is a NextGen Precision Health investigator. He obtained his PhD from Texas A&M University, and he also has a Doctor of Veterinary Medicine degree. Neekun Sharma is an assistant research professor within the Division of Endocrinology and Metabolism in the Department of Medicine.
The study titled “Chronic Intermittent Hypoxia Facilitates the Development of Angiotensin II-Induced Abdominal Aortic Aneurysm in Male Mice” has been published in the Journal of Applied Physiology. The study team includes Martinez-Lemus and Sharma, along with Abdelnaby Khalyfa, associate research professor in Pediatrics; Dunpeng Cai, assistant surgery professor; Mariana Morales-Quinones, senior research specialist; Shi-You Chen, Division Chief of Surgical Research; Jaume Padilla, associate professor of Nutrition and Exercise Physiology; Camila Manrique-Acevedo, endocrinologist at MU Health Care; and Bysani Chandrasekar, a professor in the Department of Cardiology. Contributions were also made by Rogerio Soares, Yusuke Higashi, and David Gozal.
