A new study published in the Jan. 6, 2016 online edition of Science Translational Medicine revealed some of the reasons why people with sleep apnea have an increased risk of heart disease. The study also showed how cholesterol-lowering statin medications may help address these reasons and thereby lower the risk of heart disease.
According to statistics, obstructive sleep apnea is seen in more than 18 million adults. It is a condition in which relaxation of muscles in the throat during sleep causes a repeated stop and start pattern of breathing. Not surprisingly, the condition disrupts sleep and causes fluctuations in oxygen levels. This can lead to increased daytime sleepiness and also severe lapses in concentration. Sleep apnea has also been shown to triple the risk for developing hypertension, ischemic stroke, and other forms of heart disease.
The study which was conducted at Columbia University Medical Center (CUMC) included 128 people who underwent sleep studies at CUMC’s Sleep Disorders Center. These included 76 people who met the criteria to me diagnosed as obstructive sleep apnea patients and 52 people who did not meet the criteria.
According to Sanja Jelic, MD, associate professor of medicine at CUMC, the purpose of the study was to understand how sleep apnea leads to hear disease. Prior to the study, the research team knew that sleep apnea is a powerful and independent risk factor for heart disease, but mechanisms by which sleep apnea led to heart disease was unclear.
As part of the study, the researchers took blood from the participants’ arm veins and analyzed cells that line blood vessel walls. They were looking for differences that may bring to light the reason behind the increased risk for heart disease in people with sleep apnea.
The team discovered that there was a higher level of a certain protein (CD59) in the cells of the people with sleep apnea. CD59 is a protein normally found ON the cell surface where it is better positioned to do its job of inhibiting the buildup of inflammatory proteins on cell surfaces.
The researchers found that in the people with sleep apnea the CD59 was found within the and not on the cell surface. This unexpected finding suggests that the stop-start pattern of breathing interferes with the oxygen flow during sleep, which in turn draws CD59 away from the cell surface. Because of this anomaly there were larger deposits of inflammatory proteins on the cells of the sleep apnea group.
As a next step the researchers, gave statin drugs to the people with sleep apnea. They noticed that statins helped preserve the CD59 on the cell surface.
This positive result provides supports the theory that statins may be considered as a primary prevention strategy for reducing heart disease risk in people with sleep apnea.
Dr. Jelic and the team believe the results of the study will help reduce the risk of heart disease in people with sleep apnea. The hope their study will pave the way for future trials which will confirm and back their findings.