Nocturnal hypoxic stress activates invasive ability of monocytes in patients with obstructive sleep apnoea syndrome.

BACKGROUND AND OBJECTIVE: Obstructive sleep apnoea syndrome (OSAS) is known to be a risk factor for cardiovascular events. However, the precise mechanism has not been fully elucidated. OSAS-induced hypoxic stress may promote the production of inflammatory cytokines and chemokines by monocytes, which has a crucial role in the development of atherosclerosis. In addition, adhesion to the vascular endothelium and transendothelial migration of monocytes are considered to induce atherosclerosis. The aim of this study was to investigate the effects of hypoxic stress on the invasive ability of monocytes in OSAS. METHODS: Twenty-one male patients with OSAS and 17 healthy male control subjects, who were matched for age and BMI, were enrolled. Venous blood samples were collected before and after sleep, and also after CPAP titration, for the purpose of monocyte isolation. The invasive ability of monocytes was evaluated by counting the number of invading cells using a BD BioCoat Matrigel Invasion Chamber. RESULTS: The number of cells, which represents the invasive ability of monocytes, was significantly higher in patients with OSAS compared with control subjects, in the early morning (P < 0.001). In patients with OSAS, invasive ability in the early morning after sleep was significantly elevated as compared with that before sleep (P < 0.001), and was positively correlated with the oxygen desaturation index (P < 0.05). CPAP titration led to a decrease in the invasive ability (P < 0.001). CONCLUSIONS: These results indicate that OSAS-induced hypoxic stress activates the invasive ability of monocytes, and that the occurrence of this phenomenon during sleep may contribute to the development of atherosclerosis in OSAS.

Effect of serum leptin levels on hypercapnic ventilatory response in obstructive sleep apnea.

BACKGROUND: Leptin levels have been reported to be higher in patients with obstructive sleep apnea (OSA) than in control subjects with matching age and body mass index (BMI). Although animal studies have shown that leptin augments hypercapnic ventilatory response (HCVR), the effect of leptin on HCVR has not been clarified in OSA. OBJECTIVES: To investigate whether leptin could augment HCVR during wakefulness in patients with OSA. METHODS: Of 134 consecutive patients with OSA, 13 eucapnic and 16 hypercapnic patients with OSA, and 12 control subjects matched for sex, age, and BMI were selected. Fasting serum leptin levels were collected, and HCVR during wakefulness assessed by the slope between minute ventilation and end-tidal PCO(2). RESULTS: There was a significant positive relationship between serum leptin levels and HCVR in the group including control subjects and eucapnic patients with OSA (r = 0.42, p < 0.05). Subgroup analyses suggest that serum leptin levels and HCVR were significantly higher in eucapnic patients with OSA than in control subjects. On the other hand, hypercapnic patients had lower HCVR than eucapnic patients (p < 0.05), whereas serum leptin levels were similar between the two OSA subgroups. CONCLUSION: Leptin levels and HCVR are correlated as long as the eucapnic condition is maintained. We speculate that a stimulating effect of leptin on HCVR may be masked by the hypoventilation state.

[A familial case of summer-type hypersensitivity pneumonitis possibly associated with bird breeder's lung diagnosed by bronchoalveolar lavage fluid].

Case 1: A 32-year-old woman had cough and exertional dyspnea in August 2002, and chest computed tomographic scan revealed diffuse centrilobular nodules. Bronchoalveolar lavage fluid (BALF) showed a high proportion of lymphocytes with a decreased CD 4/CD 8 ratio. Transbronchial lung biopsy (TBLB) specimens showed alveolitis. Summer-type hypersensitivity pneumonitis was diagnosed on the basis of positive findings of anti-Trichosporon antibodies in the serum. Case 2: A 64-year-old man, the father of Case 1, also had cough and exertional dyspnea in August 2003. He had been in close contact with pigeons. Chest computed tomographic scan revealed bilateral map-like ground-glass opacities predominantly in the upper lobes. BALF showed a high proportion of lymphocytes with a decreased CD 4/CD 8 ratio. TBLB specimens showed alveolitis, granuloma and Masson body in the air spaces. Specific IgG and IgA antibodies against Trichosporon asahii, IgA antibodies against Trichosporon mucoides, and IgA antibodies against pigeon dropping extracts were found only in the BALF but not in the serum. Although a positive finding of returning-home provocation test was definitive in diagnosing summer-type hypersensitivity pneumonitis, he was also suspected of having bird fancier's lung.

Production of inflammatory mediators by monocytes in patients with obstructive sleep apnea syndrome.

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is known to be a risk factor of cardiovascular events. However, the precise mechanism linking the two has not been fully elucidated. OBJECTIVE: The aim of this study was to investigate the effect of hypoxic stress on the production of tumor necrosis factor (TNF)-alpha, monocyte chemoattractant protein-1 (MCP-1), and matrix metalloproteinase-9 (MMP-9) by monocytes. METHODS: Thirty-three OSAS patients and 13 healthy control subjects were enrolled. The OSAS patients were classified as mild-to-moderate (13) and severe (20). Venous blood samples were collected before and after sleep as well as after long-term nasal continuous positive airway pressure (CPAP) treatment for the purpose of isolation of monocytes. Peripheral blood monocytes were isolated using standard methods. Monocytes were cultured under lipopolysaccharide stimulation for 24 hours, and TNF-alpha, MCP-1, and MMP-9 in the culture supernatants were determined by ELISA. RESULTS: In severe patients, the TNF-alpha production by monocytes was significantly elevated as compared to that before sleep (p<0.01). In all OSAS patients, the TNF-alpha production after sleep was significantly correlated with AHI (p<0.01), ODI (p<0.01) and % time in SpO(2)<90% (p<0.05), and inversely correlated with the lowest SpO(2) (p<0.01). The production of MCP-1 and MMP-9 by monocytes was significantly elevated compared to that before sleep in severe patients (p<0.05). The production of these mediators by monocytes was significantly decreased after long-term nasal CPAP treatment (p<0.05). CONCLUSION: These results indicate that OSAS-induced hypoxic stress activates the production of inflammatory mediators by monocytes.

Acute pulmonary thromboembolism associated with interstitial pneumonia.

A 68-year-old woman, who had been diagnosed as idiopathic interstitial pneumonia, complained of progressive dyspnea on exertion for a week. Although her chest radiograph did not worsen, arterial blood gas findings were markedly worsened. Contrast-enhanced chest computed tomography showed filling defects of the right upper and middle lobe branches of the pulmonary artery. She was diagnosed as having acute pulmonary thromboembolism (APTE). Clinical symptoms and contrast-enhanced chest computed tomography findings were remarkably improved after the treatment with heparin and urokinase. APTE should be considered as a differential diagnosis in patients with interstitial pneumonia who have worsening of respiratory symptoms with unchanged chest radiograph.

Evidence for activation of nuclear factor kappaB in obstructive sleep apnea.

Obstructive sleep apnea (OSA) is a risk factor for atherosclerosis, and atherosclerosis evolves from activation of the inflammatory cascade. We propose that activation of the nuclear factor kappaB (NF-kappaB), a key transcription factor in the inflammatory cascade, occurs in OSA. Nine age-matched, nonsmoking, and non-hypertensive men with OSA symptoms and seven similar healthy subjects were recruited for standard polysomnography followed by the collection of blood samples for monocyte nuclear p65 concentrations (OSA and healthy groups). In the OSA group, p65 and of monocyte production of tumor necrosis factor alpha (TNF-alpha) were measured at the same time and after the next night of continuous positive airway pressure (CPAP). p65 Concentrations in the OSA group were significantly higher than in the control group [median, 0.037 ng/microl (interquartile range, 0.034 to 0.051) vs 0.019 ng/microl (interquartile range, 0.013 to 0.032); p = 0.008], and in the OSA group were significantly correlated with apnea-hypopnea index and time spent below an oxygen saturation of 90% (r = 0.77 and 0.88, respectively) after adjustment for age and BMI. One night of CPAP resulted in a reduction in p65 [to 0.020 ng/mul (interquartile range, 0.010 to 0.036), p = 0.04] and levels of TNF-alpha production in cultured monocytes [16.26 (interquartile range, 7.75 to 24.85) to 7.59 ng/ml (interquartile range, 5.19 to 12.95), p = 0.01]. NF-kappaB activation occurs with sleep-disordered breathing. Such activation of NF-kappaB may contribute to the pathogenesis of atherosclerosis in OSA patients.