Interleukin-6 and Tumor Necrosis Factor-α in Patients with Obstructive Sleep Apnea-Hypopnea Syndrome

Circulating ICAM-1 and VCAM-1 levels in patients with obstructive sleep apnea syndrome

BACKGROUND

Obstructive sleep apnea syndrome (OSAS)-induced hypoxic stress modulates circulating inflammatory mediators causing accelerated atherogenesis.

OBJECTIVES

We hypothesized that OSAS-induced hypoxia might result in cardiovascular disease due to increased expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) on the endothelial surface.

METHODS

Thirty-nine subjects with moderate-to-severe OSAS and 34 non-apneic controls matched for age, gender, body mass index (BMI), smoking history, and cardiovascular disease were included in this prospective study. Overnight polysomnography was performed. Circulating ICAM-1 and VCAM-1 levels in the serum were measured by enzyme-linked immunosorbent assay.

RESULTS

Circulating levels of both ICAM-1 (480.1 +/- 216.7 vs. 303.4 +/- 98.6 ng/ml, p < 0.0001) and VCAM-1 (1,156.6 +/- 79.8 vs. 878.8 +/- 71.1 ng/ml, p = 0.002) were significantly increased in the OSAS group compared to the control group. For an ICAM-1 cutoff level of 375 ng/ml, predictive sensitivity and specificity for OSAS were 69.2% (95% confidence interval, CI: 52.4-83.0%) and 82.4% (95% CI: 65.5-93.2%), respectively. For a VCAM-1 cutoff level of 859 ng/ml, predictive sensitivity and specificity for OSAS were 74.4% (95% CI: 57.9-86.9%) and 64.7% (95% CI: 46.5-80.2%), respectively. There was a significant positive correlation between circulating levels of ICAM-1 and ln of AHI (r = 0.276, p = 0.018). Multiple logistic regression analyses showed that OSAS was associated with high ICAM-1 and high VCAM-1 levels independent of age, gender, BMI, smoking status and cardiovascular disease.

CONCLUSION

We conclude that OSAS can independently increase circulating levels of adhesion molecules

Association of Elevated Levels of Vascular Endothelial Growth Factor in Obstructive Sleep Apnea Syndrome with Patient Age rather than with Obstructive Sleep Apnea Syndrome Severity

BACKGROUND

Although certain studies report high levels of vascular endothelial growth factor (VEGF) in obstructive sleep apnea syndrome (OSAS), the effect of systemic hypoxia on circulating VEGF remains controversial.

OBJECTIVES

To study the association of serum VEGF and OSAS in a large group of patients.

METHODS

One hundred patients with OSAS (mean age 58.1+/-12.4 years, mean body mass index 30.6+/-5.4 kg/m2) were tested for serum VEGF levels, and the findings were correlated with the severity of OSAS, as determined by the apnea-hypopnea index (AHI) on the basis of polysomnography and background data.

RESULTS

The mean AHI was 40.0+/-21.2 (range 10-106). Mean minimal oxygen saturation was 80.6+/-11.7% (range 43-98%) and mean time of oxygen saturation under 90% was 50.0+/-75.0 min (range 0-300 min). The mean VEGF level was 445.2+/-289.8 pg/ml in the study group (vs. 280 pg/ml reported in normal controls). The mean platelet count was 233.8+/-64.4 10(3)/ml and the mean VEGF/platelet ratio was 1.95+/-1.40 pg/10(6). There was no association of VEGF or VEGF/platelets with the severity of OSAS. However, both factors showed a significant correlation with patient age (r=0.224, p=0.01 and r=0.425, p=0.01, respectively). Age was the only parameter to significantly predict VEGF and VEGF/platelets on multivariate analysis (R2=0.713, p=0.001 and R2=0.844, p=0.001, respectively).

CONCLUSION

The elevation of serum VEGF in OSAS is not associated with the severity of the disease, but it is associated with patient age. VEGF might be involved in the long-term adaptive mechanism in OSAS, and its age-dependent increase might partly explain the reduced mortality in elderly OSAS patients.

Relationship between adhesion molecules with hs-CRP and changes therein after ARB (Valsartan) administration in patients with obstructive sleep apnea syndrome

It has been reported that a relationship exists between obstructive sleep apnea syndrome (OSAS) and cardiovascular and cerebrovascular diseases. To address this issue, we evaluated whether OSAS is associated with adhesion molecules and inflammatory signs, important indicators of atherosclerosis. Levels of high-sensitivity CRP (hs-CRP) and intercellular adhesion molecule-1 (ICAM-1) were measured in 30 patients with ischemic heart disease, confirmed by coronary arteriography (IHD group). Twenty healthy volunteers without sleep apnea were used as controls (Group N). Sleeping respiratory information was collected using a portable sleep polygraph, together on information about oronasal flow, tracheal sound, chest respiration, and percutaneous oxygen saturation (SpO2) to obtain the apnea-hypopnea index (AHI). In the IHD group, 9 (30%) of the 30 patients showed evidence of OSAS [IHD(AHI> or = 40) group] and 21 did not [IHD(AHI<40) group]. The levels of hs-CRP and ICAM-1 were significantly higher in the IHD group than in the N group (p<0.01). Moreover, the levels of hs-CRP and ICAM-1 were significantly higher in the IHD(AHI > or = 40) group than in the IHD(AHI<40) group (p<0.01). However, after the administration of valsartan, angiotensin II receptor antagonists (ARB) to both IHD groups, the levels of hs-CRP and ICAM-1 decreased significantly in both groups. Moreover, a multivariate analysis revealed that the levels of hs-CRP and ICAM-1 were associated with the severity of sleep apnea. These findings suggest that, in OSAS the levels of hs-CRP and ICAM-1 are decreased and that the administration of ARB decreases the risk of atherosclerosis.

Oxidant stress and inflammation in the snoring child: confluent pathways to upper airway pathogenesis and end-organ morbidity

Snoring in children is increasingly being recognized as a highly prevalent condition, and indicates the presence of heightened upper airway resistance during sleep. In this paper, we present evidence to support the hypothesis that local inflammatory processes within the upper airway contribute to the pathophysiology of adenotonsillar hypertrophy and altered reflexes potentially leading to increased propensity for upper airway obstruction during sleep. Furthermore, the cumulative evidence supporting multiorgan morbidity for sleep-disordered breathing (SDB) is reviewed, and a unified hypothesis of a triple risk model proposing oxidative-inflammatory mechanisms as mediating the morbid consequences of SDB is presented. This hypothetical working model incorporates both dose-dependent disease severity components, as well as environmental and genetic elements of susceptibility.

Sleep deprivation suppresses neurogenesis in the adult hippocampus of rats

We reported previously that 96 h of sleep deprivation (SD) reduced cell proliferation in the dentate gyrus (DG) of the hippocampus in adult rats. We now report that SD reduces the number of new cells expressing a mature neuronal marker, neuronal nuclear antigen (NeuN). Rats were sleep-deprived for 96 h, using an intermittent treadmill system. Total sleep time was reduced to 6.9% by this method in SD animals, but total treadmill movement was equated in SD and treadmill control (CT) groups. Rats were allowed to survive for 3 weeks after 5-bromo-2-deoxyuridine (BrdU) injection. The phenotype of BrdU-positive cells in the DG was assessed by immunofluorescence and confocal microscopy. After 3 weeks the number of BrdU-positive cells was reduced by 39.6% in the SD group compared with the CT. The percentage of cells that co-localized BrdU and NeuN was also lower in the SD group (SD: 46.6 +/- 1.8% vs. CT: 71.9 +/- 2.1, P < 0.001). The percentages of BrdU-labeled cells co-expressing markers of immature neuronal (DCX) or glial (S100-beta) cells were not different in SD and CT groups. Thus, SD reduces neurogenesis in the DG by affecting both total proliferation and the percentage of cells expressing a mature neuronal phenotype. We hypothesize that sleep provides anabolic or signaling support for proliferation and cell fate determination.

Leptin and ghrelin levels in patients with obstructive sleep apnea syndrome

BACKGROUND

Leptin is a hormone with well-investigated functions concerning body composition, energy homeostasis and feeding behavior in humans. The obstructive sleep apnea syndrome (OSAS) is strongly associated with obesity, which is known to be closely associated with hyperleptinemia. More recently, ghrelin, a hormone that also influences appetite and energy homeostasis, has been discovered.

OBJECTIVES

The aim of this study was to investigate serum leptin and ghrelin levels in obese patients with OSAS in comparison with equally obese controls without OSAS.

METHODS

Thirty untreated obese patients with moderate-severe OSAS (apnea-hypopnea index: AHI > or =15) and 22 obese controls (AHI <5) were studied. To confirm the diagnosis, all patients underwent standard polysomnography in our sleep disorders center. Serum samples were taken at 08:00 h in the morning after overnight fasting.

RESULTS

Significantly higher serum leptin levels were found in OSAS patients compared to controls (p = 0.012), but there was no significant difference in serum ghrelin levels between OSAS patients and controls. Serum leptin levels were significantly correlated with body mass index in both OSAS patients (r = 0.55, p = 0.002) and controls (r = 0.46, p = 0.028), but only in OSAS patients was the leptin level significantly correlated with AHI (r = 0.38, p = 0.036).

CONCLUSION

These data support findings suggesting that leptin is a hormonal factor affected by OSAS and not determined by obesity alone. Further studies are needed to investigate the relationship between serum ghrelin and OSAS.

Heart failure and sleep apnoea: to sleep perchance to dream

Heart failure and sleep apnoea are major health problems with an increasingly recognized association; evidence suggests that sleep apnoea may play a role in the progression of heart failure. However, confounding factors such as obesity, hypertension and coronary heart disease make this relationship uncertain and an independent correlation remains unproven. Diagnosis of sleep apnoea is suboptimal, as it is often asymptomatic and polysomnography is expensive and time-consuming. A simple and reliable screening protocol is required. All heart failure patients should be considered to be at high risk of sleep apnoea, as this association might be linked to adverse outcome. Continuous positive airway pressure has shown some beneficial effects, but long-term outcome and improvement in survival remains to be demonstrated. Despite recent advances in the understanding of the complex relationship between heart failure and sleep apnoea, there are a number of areas requiring further investigation, which may have important implications for the management and prognosis of a significant number of patients.

Adiponectin in patients with obstructive sleep apnea syndrome: course and physiological relevance

BACKGROUND

Adiponectin is an adipocyte-derived hormone with anti-inflammatory and insulin-sensitizing properties. Insulin resistance is a typical feature of the obstructive sleep apnea syndrome (OSAS).

OBJECTIVES

Since nasal continuous positive airway pressure (nCPAP) treatment improves insulin sensitivity in patients with OSAS, we investigated serum adiponectin levels before and during nCPAP treatment to clarify possible interactions between the adiponectin levels and insulin sensitivity in patients with OSAS.

METHODS

Thirty nondiabetic, obese patients with OSAS (mean age 56.4 +/- 11.1 years; apnoea-hypopnoea index (AHI) 46.03 +/- 19.57) underwent CPAP treatment. Adiponectin levels and the levels of proinflammatory cytokines and proteins reflecting platelet activation [regulated on activation normally T cell expressed and secreted (RANTES) and soluble P-selectin (sCD62p)], as well as the insulin sensitivity index were measured before, and after 2 days and 3 months of CPAP treatment.

RESULTS

Insulin sensitivity increased significantly under nCPAP treatment, whereas adiponectin levels decreased after 2 days of nCPAP treatment, but returned to baseline levels after 3 months of nCPAP treatment. The increase in insulin sensitivity was more pronounced in patients with the highest adiponectin levels at baseline (p = 0.021) after adjustment for body fat (p = 0.003). During treatment, changes in adiponectin levels were highly predictable by the insulin sensitivity index.

CONCLUSIONS

We found a significant relation between adiponectin and the insulin sensitivity index in overweight patients with OSAS. The lack of a long-lasting change in adiponectin may be explained by the overwhelming influence of the body mass index on adiponectin secretion, which was unchanged during nCPAP treatment.