Increased Adhesion Molecules Expression and Production of Reactive Oxygen Species in Leukocytes of Sleep Apnea Patients (original) (raw)
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Increased Adhesion Molecules Expression and.pdf
Obstructive sleep apnea (OSA) is associated with increased cardio-vascular morbidity and mortality. Free radicals and adhesion molecules were implicated in the pathogenesis of atherosclerosis leading to cardiovascular disorders. Therefore, we investigated the link between CD15, CD11c, CD11b, and CD64 expression on leukocytes and their ability to generate reactive oxygen species (ROS) in patients with OSA and control volunteers. We also studied the effects of hypoxia in vitro on monocytes from control subjects and the ability of monocytes from both groups to adhere to human endothelial cells in culture. The effect of nasal continuous positive airway pressure (nCPAP) treatment was studied as well. We found that OSA was associated with increased expression of adhesion molecules CD15 and CD11c on monocytes, increased adherence of monocytes in culture to human endothelial cells, increased intra-cellular ROS production in some monocyte and granulocyte sub-populations, and upregulation of CD15 expression due to hypoxia in vitro in monocytes of control subjects. Furthermore, nCPAP treatment was associated with downregulation of CD15 and CD11c monocyte expression and decreased basal ROS production in CD11c monocytes. Monocyte adherence to endothelial cells decreased as well. Our findings provide one of the possible mechanisms for explaining the high rate of cardiovascular morbidity in patients with sleep apnea.
Delayed Neutrophil Apoptosis in Patients with Sleep Apnea
American Journal of Respiratory and Critical Care Medicine, 2008
Rationale: Obstructive sleep apnea (OSA), characterized by intermittent hypoxia/reoxygenation (IHR), is associated with atherosclerosis. Polymorphonuclear leukocytes (PMNs) are implicated in atherogenesis by producing oxidizing radicals and proteolytic enzymes during PMN-endothelium interactions. PMN apoptosis is a fundamental, injury-limiting mechanism, which prevents their destructive potential. Objectives: To determine whether PMN apoptosis and expression of adhesion molecules are affected by OSA and IHR in vitro. Methods: Apoptosis and expression of adhesion molecules were assessed in whole blood PMNs by flow cytometry, verified by various culture conditions, and morphology. These were complemented by exposing whole blood and purified PMNs to IHR and to sustained hypoxia in vitro. Measurements and Main Results: This study demonstrates for the first time that, in patients with moderate to severe OSA, PMN apoptosis is delayed. Apoptosis was attenuated in patients with an apneahypopnea index (AHI) of more than 15, determined by decreased expression of low-CD16/annexin-V-positive PMNs, by lowered caspase-3 activity and nuclear condensation. Concomitantly, selectin-CD15 expression was increased in a severity-dependent manner in patients with moderate to severe OSA having an AHI greater than 15. The percentage of apoptotic PMNs was negatively correlated with OSA severity, determined by AHI, and positively with CD15 expression. In nasal continuous positive airway pressure-treated patients, CD15 expression was attenuated and low CD16 was increased, whereas omitting nasal continuous positive airway pressure for a single night increased CD15 expression and decreased the percentage of low CD16. IHR in vitro delayed PMN apoptosis as well. Conclusions: Decreased apoptosis and increased expression of adhesion molecules were noted in OSA PMNs. Although adhesion molecules may facilitate increased PMN-endothelium interactions, decreased apoptosis may further augment these interactions and facilitate free radical and proteolytic enzyme release.
Circulation, 2008
Background-Indirect evidence implicates endothelial dysfunction in the pathogenesis of vascular diseases associated with obstructive sleep apnea (OSA). We investigated directly whether dysfunction and inflammation occur in vivo in the vascular endothelium of patients with OSA. The effects of continuous positive airway pressure (CPAP) therapy on endothelial function and repair capacity were assessed. Methods and Results-Thirty-two patients with newly diagnosed OSA and 15 control subjects were studied. Proteins that regulate basal endothelial nitric oxide (NO) production (endothelial NO synthase [eNOS] and phosphorylated eNOS) and inflammation (cyclooxygenase-2 and inducible NOS) and markers of oxidative stress (nitrotyrosine) were quantified by immunofluorescence in freshly harvested venous endothelial cells before and after 4 weeks of CPAP therapy. Vascular reactivity was measured by flow-mediated dilation. Circulating endothelial progenitor cell levels were quantified to assess endothelial repair capacity. Baseline endothelial expression of eNOS and phosphorylated eNOS was reduced by 59% and 94%, respectively, in patients with OSA compared with control subjects. Expression of both nitrotyrosine and cyclooxygenase-2 was 5-fold greater in patients with OSA than in control subjects, whereas inducible NOS expression was 56% greater. Expression of eNOS and phosphorylated eNOS significantly increased, whereas expression of nitrotyrosine, cyclooxygenase-2, and inducible NOS significantly decreased in patients who adhered to CPAP Ն4 hours daily. Baseline flow-mediated dilation and endothelial progenitor cell levels were lower in patients than in control subjects, and both significantly increased in patients who adhered to CPAP Ն4 hours daily. Conclusions-OSA directly affects the vascular endothelium by promoting inflammation and oxidative stress while decreasing NO availability and repair capacity. Effective CPAP therapy is associated with the reversal of these alterations. The online-only Data Supplement, which contains Methods and tables, can be found with this article at http://circ.ahajournals.org/cgi/content/ full/CIRCULATIONAHA.107.741512/DC1.
Oxidative stress inflammation and endothelial dysfunction in obstructive sleep apnea
Frontiers in bioscience (Elite edition), 2012
Obstructive sleep apnea syndrome (OSA) is a breathing disorder in sleep. In recent years, this entity has emerged as a major public health problem due to its high prevalence and the profound impact on patients' health and quality of life. A large body of evidence identified OSA as an independent risk factor for cardiovascular morbidity and mortality. Also an association was demonstrated with additional cardiovascular risk factors. This has led to intensive research on the mechanisms involved. The main characteristics of OSA are the recurrent pauses in respiration which result in intermittent hypoxia (IH) and hypercapnia, accompanied by decreased blood oxygen saturation and arousals during sleep. The associations of OSA with cardiovascular morbidities rely on the cyclic nature of the IH, and implicate the apnea related multiple cycles of hypoxia/reoxygenation with increased production of reactive oxygen species (ROS), thereby initiating inflammation. This review summarizes the ma...
Phenotypic and Functional Characterization of Blood gammadelta T cells in sleep apnea.pdf
Hypoxia-induced lymphocyte dysfunction may be implicated in endothelial cell damage in obstructive sleep apnea (OSA) syndrome. ␥␦ T cells' unique migration, cytotoxic features, and accumulation in atherosclerotic plaques are considered critical in cardiovascular disorders. We characterized the phenotype, cytokine profile, adhesion properties, and cytotoxicity of ␥␦ T cells in patients with OSA and control subjects. The following is a summary of our major findings regarding OSA ␥␦ T cells: (1 ) a significant increase in the expression of the inhibitory natural killer B1 receptors was found; (2 ) the intracellular content of proinflammatory cytokines tumor necrosis factor (TNF)-␣ and interleukin-8 was increased, and the content of the antiinflammatory cytokine interleukin-10 was decreased; (3 ) ␥␦ T cells of patients with OSA adhered significantly more avidly to nonactivated endothelial cells in culture than those of control subjects; (4 )
PLoS ONE, 2014
Background: Obstructive sleep apnea (OSA) is known to be a risk factor of coronary artery disease. The chemotaxis and adhesion of monocytes to the endothelium in the early atherosclerosis is important. This study aimed to investigate the effect of intermittent hypoxia, the hallmark of OSA, on the chemotaxis and adhesion of monocytes. Methods: Peripheral blood was sampled from 54 adults enrolled for suspected OSA. RNA was prepared from the isolated monocytes for the analysis of CC chemokine receptor 2 (CCR2). The effect of intermittent hypoxia on the regulation and function of CCR2 was investigated on THP-1 monocytic cells and monocytes. The mRNA and protein expression levels were investigated by RT/real-time PCR and western blot analysis, respectively. Transwell filter migration assay and cell adhesion assay were performed to study the chemotaxis and adhesion of monocytes. Results: Monocytic CCR2 gene expression was found to be increased in severe OSA patients and higher levels were detected after sleep. Intermittent hypoxia increased the CCR2 expression in THP-1 monocytic cells even in the presence of TNF-a and CRP. Intermittent hypoxia also promoted the MCP-1-mediated chemotaxis and adhesion of monocytes to endothelial cells. Furthermore, inhibitor for p42/44 MAPK or p38 MAPK suppressed the activation of monocytic CCR2 expression by intermittent hypoxia. Conclusions: This is the first study to demonstrate the increase of CCR2 gene expression in monocytes of severe OSA patients. Monocytic CCR2 gene expression can be induced under intermittent hypoxia which contributes to the chemotaxis and adhesion of monocytes.
Oxidative Stress and Inflammation Biomarker Expression in Obstructive Sleep Apnea Patients
Journal of Clinical Medicine
Obstructive Sleep Apnea Syndrome (OSAS) is a respiratory sleep disorder characterised by repeated episodes of partial or complete obstruction of the upper airway during the night. This obstruction usually occurs with a reduction (hypopnea) or complete cessation (apnea) of the airflow in the upper airways with the persistence of thoracic-diaphragmatic respiratory movements. During the hypopnea/apnea events, poor alveolar ventilation reduces the oxygen saturation in the arterial blood (SaO2) and a gradual increase in the partial arterial pressure of carbon dioxide (PaCO2). The direct consequence of the intermittent hypoxia is an oxidative imbalance, with reactive oxygen species production and the inflammatory cascade’s activation with pro and anti-inflammatory cytokines growth. Tumour necrosis factors, inflammatory cytokines (IL2, IL4, IL6), lipid peroxidation, and cell-free DNA have been found to increase in OSAS patients. However, even though different risk-related markers have been...