Early and mid-term effects of obstructive apneas in myocardial injury and inflammation

Abstract

Background: Obstructive sleep apnea (OSA) is associated with cardiovascular disorders, but the different comorbidities in OSA patients make it difficult to know their specific effects on the development of cardiovascular injury. The aim of the present study was to investigate whether recurrent obstructive apneas could lead to myocardial injury.

Methods: Thirty-six male Sprague-Dawley rats (300-350 g) were either acutely (3 h) or sustainably (5 h/day, for 10 days) subjected to obstructive apneas with a pattern of 15 s each, 60 apneas/h. Corresponding control groups were formed for the acute and sustained models. To assess the induction of systemic inflammation, IL1-β was measured in plasma. Ventricular tissue injury was evaluated by histological techniques (presence of inflammatory cell infiltration, eosin autofluorescence, and detection of apoptosis).

Results: After 3h of obstructive apneas, a significant increase in IL1-β (64.9±29.6 ng/μl) were observed with respect to the controls (7.3±1.0 ng/μl), but no myocardial injury was present. Conversely to the acute model, the systemic inflammation triggered by obstructive apneas for 10 days was reduced. However, the percentage of area with enhanced eosin autofluorescence and of apoptotic cells (1.83±0.35% and 24.4±1.5%, respectively) was increased when compared to the control group (0.72±0.20% and 5.0±2.8%, respectively).

Conclusions: This study suggests that obstructive apneas are a potential source of early systemic and ventricular inflammation and myocardial cell injury after sustained apneas application, which could represent an initial phase in the progression of heart disease associated with OSA.