Tissue oxygenation in brain, muscle and fat in a rat model of sleep apnea: differential effect of obstructive apneas and intermittent hypoxia.

Study Objectives: To test the hypotheses that the dynamic changes in brain oxygen partial pressure (PtO 2) in response to obstructive apneas or to intermittent hypoxia differ from those in other organs and that the changes in brain PtO 2 in response to obstructive apneas is a source of oxidative stress. Design: Prospective controlled animal study. Setting: University laboratory. Participants: 98 Sprague-Dawley rats. Interventions: Cerebral cortex, skeletal muscle, or visceral fat tissues were exposed in anesthetized animals subjected to either obstructive apneas or intermittent hypoxia (apneic and hypoxic events of 15 s each and 60 events/h) for 1 h. Measurements and Results: Arterial oxyge…

Pre-treatment with mesenchymal stem cells reduces ventilator-induced lung injury

ckground information: Bone marrow-derived mesenchymal stem cells (MSCs) reduce acute lung injury in animals challenged by bleomycin or bacterial lipopolysaccaride. It is not known, however, whether MSCs protect from ventilator- induced lung injury (VILI). Question of the study: Whether MSCs have a potential role in preventing or modulating VILI in healthy rats subjected to high-volume ventilation. Materials and methods: 24 Sprague-Dawley rats (250-300 g) were subjected to high- volume mechanical ventilation (25 ml/kg). MSCs (5x106) were intravenously or intratracheally administered (N=8 each) 30 min before starting over-ventilation and 8 rats were MSC-untreated. Spontaneously breathing anes…

Obesity and intermittent hypoxia increase tumor growth in a mouse model of sleep apnea.

Background: Intermittent hypoxia and obesity which are two pathological conditions commonly found in patients with obstructive sleep apnea (OSA), potentially enhance cancer progression. Objective: To investigate whether obesity and/or intermittent hypoxia (IH) mimicking OSA affect tumor growth. Methods: A subcutaneous melanoma was induced in 40 mice [22 obese (40–45 g) and 18 lean (20–25 g)] by injecting 106 B16F10 cells in the flank. Nineteen mice (10 obese/9 lean) were subjected to IH (6 h/day for 17 days). A group of 21 mice (12 obese/9 lean) were kept under normoxia. At day 17, tumors were excised, weighed and processed to quantify necrosis and endothelial expression of vascular endothe…

Cellular basis of abnormal tissue hardening in lung fibrosis examined with atomic force microscopy

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 p…