Obstructive sleep apnoea may be a risk factor for developing abdominal aortic aneurysms, according to researchers from the University of Missouri School of Medicine and NextGen Precision Health.
Abdominal aortic aneurysms occur when the aorta swells and potentially ruptures, causing life-threatening internal bleeding. Obstructive sleep apnoea is characterised by episodes of a complete or partial airway collapse with an associated drop in oxygen saturation or arousal from sleep. It can increase the risk of developing cardiovascular problems. Citing studies that indicate a higher prevalence of abdominal aortic aneurysms in patients with obstructive sleep apnoea, MU researchers examined the link between the two using mouse models.
The research team found that intermittent hypoxia caused by obstructive sleep apnoea increased the susceptibility of mice to develop abdominal aortic aneurysms.
“Chronic intermittent hypoxia by itself is not enough to cause abdominal aortic aneurysms, but for a patient with obstructive sleep apnoea who also has additional metabolic problems like obesity, our findings suggest it may help degrade aortic structures and promote aneurysm development,” said Luis Martinez-Lemus, study author and a professor of medical pharmacology and physiology.
Intermittent hypoxia happens during obstructive sleep apnoea when throat muscles relax and block the flow of air into the lungs. According to the research, the loss of oxygen triggers certain enzymes called MMPs. The increased enzyme activity can degrade the extracellular matrix, which acts like a cell scaffolding network, weakening the aorta.
“Patients with abdominal aortic aneurysms usually don’t notice any symptoms, except for some back and belly pain, until the aneurysm bursts. Once that happens, it’s crucial to get the patient to surgery quickly so doctors can repair the aorta,” said Neekun Sharma, the lead author of the study. “Learning how these aneurysms develop can help us find ways to monitor or slow down their progression, especially for patients who have obstructive sleep apnoea.”
Source: University of Missouri-Columbia
