Plasma cytokine levels in patients with obstructive sleep apnea syndrome: a preliminary study

Inflammatory cytokines in pediatric obstructive sleep apnea

Pediatric obstructive sleep apnea (OSA) is associated with chronic systemic inflammation and with cognitive impairments. This study aimed to investigate the status of proinflammatory cytokines, particularly interleukin 17 (IL-17) and interleukin 23 (IL-23) and cognition in pediatric OSA.Controls and OSA children participated in the study. Exclusion criteria were adenotonsillectomy, heart, neurological and severe psychiatric diseases, craniofacial syndromes, and obesity. Polysomnogram was followed by serum testing for inflammatory markers and neurocognitive tests such as continuous performance task (CPT) and Wisconsin card sorting test, questionnaires, analyses of plasma high-sensitivity C-reactive protein (HS-CRP), tumor necrosis factor alpha (TNF-α), interleukin 1 (IL-1), interleukin 6 (IL-6), IL-17, and IL-23.Seventy-nine, 4 to 12-year-old subjects in 2 groups ended the study: 47 nonobese OSA children (mean age = 7.84 ± 0.56 years, body mass index [BMI] = 16.95 ± 0.47 kg/m, BMI z-score = 0.15 ± 0.21, and mean apnea-hypopnea index [AHI] = 9.13 ± 1.67 events/h) and 32 healthy control children (mean age = 7.02 ± 0.65 years, with BMI = 16.55 ± 0.58 kg/m, BMI z-score = -0.12 ± 0.27, and mean AHI = 0.41 ± 0.07 event/h) were enrolled. Serum cytokine analyses showed significantly higher levels of HS-CRP, IL-17, and IL-23 in OSA children (P = 0.002, P = 0.024, and P = 0.047). Regression test showed significant influence of HS-CRP, TNF-α, IL-6, IL-17, and specifically IL-23, with the continuous performance test and Wisconsin card sorting test.OSA children have abnormal levels of IL-17, an interleukin related to T helper 17 cells, a T helper cell involved in development of autoimmunity and inflammation. This high expression level may contribute to the complications of pediatric OSA; we also found a significant influence of inflammatory cytokines, particularly IL-23, on abnormal neurocognitive testing.

Management and Risk Reduction of Rheumatoid Arthritis in Individuals with Obstructive Sleep Apnea: A Nationwide Population-Based Study in Taiwan

STUDY OBJECTIVES

To explore associations between obstructive sleep apnea (OSA) and autoimmune diseases and evaluate whether OSA management reduces the incidence of autoimmune diseases.

METHODS

This was a retrospective cohort study using nationwide database research. The data was from 105,846 adult patients in whom OSA was diagnosed and recorded in the Taiwan National Health Insurance Research Database between 2002 and 2011 were the patients were analyzed retrospectively. Patients with antecedent autoimmune diseases were excluded. A comparison cohort of 423,384 participants without OSA served as age- and sex-matched controls. Multivariable Cox regression analysis was performed on both cohorts to compute risk of autoimmune diseases during follow-up. Time-dependent OSA treatment effect was analyzed among patients with OSA. There were no interventions.

RESULTS

Among patients with OSA, overall risk for incident autoimmune diseases was significantly higher than that in controls (adjusted hazard ratio [HR] = 1.95, 95% confidence interval [CI] = 1.66-2.27). Risk for individual autoimmune diseases, including rheumatoid arthritis (RA), Sjögren syndrome (SS), and Behçet disease, was significantly higher in patients with OSA than in controls (HRs [95% CI]: RA 1.33 [1.03-1.72, SS 3.45 [2.67-4.45] and Behçet disease 5.33 [2.45-12.66]). Increased risk for systemic lupus erythematosus (HR 1.00 [0.54-1.84]) and systemic sclerosis (HR 1.43 [0.51-3.96]) did not reach statistical significance. Patients with OSA receiving treatment had an overall reduced risk of RA and other autoimmune diseases (time-dependent HRs [95% CI]: 0.22 [0.05-0.94] and 0.51 [0.28-0.92], respectively).

CONCLUSIONS

Patients with OSA are associated with higher risk for developing RA, SS, and Behçet disease. OSA management is associated with reduced risk of RA.

The Interaction between Obstructive Sleep Apnea and Parkinson's Disease: Possible Mechanisms and Implications for Cognitive Function

Parkinson's disease (PD) is a relentlessly progressive neurodegenerative disorder associated with hallmark motor and nonmotor symptoms (NMS) such as sleep disturbances and cognitive dysfunction. While dopaminergic treatments have improved the motor aspects of PD, progression remains inevitable. Research has recently increasingly focused on strategies to modify disease progression and on nonmotor manifestations of PD, given their impact on patients' quality of life. Obstructive sleep apnea (OSA) is a treatable sleep disorder, common in the general population, associated with excessive daytime sleepiness and neurocognitive deficits. Neuroimaging has demonstrated structural and functional changes in OSA patients; in animal models, OSA causes brain inflammation and oxidative injury, including in key areas involved in PD pathophysiology such as locus coeruleus. The prevalence of OSA in PD has been variable in studies to date, and potential consequences and interrelationship between the two disorders have not been well studied. There is however emerging evidence that OSA is associated with increased NMS in PD, particularly cognitive dysfunction. This review focuses on the possible interrelationship between OSA and PD. Mechanisms promoting OSA in PD will be reviewed, as well as mechanisms whereby OSA can affect the neurodegenerative process in PD.

Inflammation induced by increased frequency of intermittent hypoxia is attenuated by tempol administration

The levels of serum inflammatory cytokines and the activation of nuclear factor kappa B (NF-κB) and hypoxia inducible factor-1α (HIF-1α) in heart tissues in response to different frequencies of intermittent hypoxia (IH) and the antioxidant tempol were evaluated. Wistar rats (64 males, 200-220 g) were randomly divided into 6 experimental groups and 2 control groups. Four groups were exposed to IH 10, 20, 30, or 40 times/h. The other 2 experimental groups were challenged with IH (30 times/h) plus tempol, either beginning on day 0 (IH30T0) or on day 29 (IH30T29). After 6 weeks of challenge, serum levels of tumor necrosis factor (TNF)-α, intracellular adhesion molecule (ICAM)-1, and interleukin-10 were measured, and western blot analysis was used to detect NF-κB p65 and HIF-1α in myocardial tissues. Serum levels of TNF-α and ICAM-1 and myocardial expression of NF-κB p65 and HIF-1α were all significantly higher in IH rats than in controls (P<0.001). Increased IH frequency resulted in more significant changes. Administration of tempol in IH rats significantly reduced levels of TNF-α, ICAM-1, NF-κB and HIF-1α compared with the non-tempol-treated group (F=16.936, P<0.001). IH induced an inflammatory response in a frequency-dependent manner. Additionally, HIF-1α and NF-κB were increased following IH administration. Importantly, tempol treatment attenuated this effect.

Th17/Treg balance in children with obstructive sleep apnea syndrome and the relationship with allergic rhinitis

OBJECTIVE

This study aims to explore the role of the Th17 to Treg cell ratio in children with OSA and its relationship with allergic rhinitis.

METHODS

The study included 127 children diagnosed with OSA by polysomnography (PSG) testing and 29 children without OSA. The 127 children with OSA were divided into the following groups: OSA with moderate adenoidal hypertrophy (n=47), OSA with severe adenoidal hypertrophy (n=49), and OSA complicated by allergic rhinitis (AR) (n=31). The adenoids of the 29 children without OSA were mildly hypertrophic. We measured the number of Th17 and Treg cells, the levels of related serum cytokines in cellular secretions, and the expression of key transcription factors in both the peripheral blood and adenoid tissue. The Th17/Treg ratio was calculated and analyzed between groups. The numbers of Th17 and Treg cells were measured by flow cytometry; the secreted IL-17, IL-10, and TGF-β were measured by ELISA; and the expression levels of RORγt and Foxp3 were measured by RT-PCR.

RESULTS

Compared with the control group, OSA children exhibited a significant increase in the number of peripheral Th17 cells, Th17-related cytokine secretion (IL-17), and RORγt mRNA levels, whereas they exhibited a decrease in the number of Treg cells, Treg-related cytokine secretions (IL-10, TGF-β) and Foxp3 mRNA levels. The Th17/Treg ratio was higher (p<0.05) in the OSA groups than in the control group. The Th17/Treg ratio was correlated with the size of the adenoids. We also found that the Th17/Treg balance in OSA patients was complicated by allergic rhinitis; the increase was significantly larger in the AR group (p<0.05, p=0.021) than in OSA groups without AR. These results were observed in both the peripheral blood and local adenoid tissue.

CONCLUSION

The Th17/Treg imbalance may increase the risk of developing OSA, and AR may promote the development of the disease. These results provide an alternative explanation for OSA pathogenesis that warrants additional research and presents new directions for the prevention and treatment of OSA in children.

Obstructive Sleep Apnoea and Vascular Disease in Patients with Type 2 Diabetes

Obstructive sleep apnoea (OSA) is common and is associated with many vascular risk factors, such as hypertension, insulin resistance, albuminuria, dyslipidaemia, increased inflammation and endothelial dysfunction. Epidemiological studies have shown that OSA is associated with increased cardiovascular disease (CVD) and that continuous positive airway pressure (CPAP) might reduce CVD events in patients with OSA. In addition, OSA has also been shown to be associated with albuminuria, chronic kidney disease, a wide range of ocular diseases and peripheral neuropathy. Considering that CVD and microvascular complications are major contributors to the morbidity, mortality and the economic burden of diabetes and that OSA is common in patients with type 2 diabetes (T2D), it is important to understand the role of OSA in the development and/or progression of vascular disease in patients with T2D and to explore the impact of CPAP on diabetes-related vascular outcomes. The purpose of this article is to review the evidence for the relationship and impact of OSA on vascular disease and vascular risk factors particularly in patients with T2D.

Association of Interleukin-10 gene promoter polymorphisms with obstructive sleep apnea

BACKGROUND

Interleukin-10 (IL) is an anti-inflammatory cytokine that regulates normal sleep patterns, and recent studies have reported that it is a potential useful biomarker to identify presence and severity of sleep apnea syndrome (OSAS). Promoter polymorphisms of IL-10 gene have been associated with altered expression levels, which contributes to OSAS.

OBJECTIVE

The aim of this study was to determine the prevalence of -1082 G/A, -819 C/T, and -592 C/A promoter polymorphisms of IL-10 gene in individuals with OSAS and controls.

SUBJECTS AND METHODS

An open-label study was performed in the Otorhinolaryngology and Sleep Disorders Outpatient Clinics. One hundred four cases with OSAS were included as the study group, and 78 individuals without OSAS were included as the controls. DNAs were extracted from peripheral blood leukocytes, and the sites that encompassed those polymorphisms were identified by DNA sequencing analyses. Data were analyzed with SNPStats and multifactor dimensionality reduction (MDR) software.

RESULTS

The prevalence of OSAS was higher in males in the study group when compared to controls (P = 0.0003). The IL-10-1082 G/A, -819 C/T, and -592 C/A SNPs, and their minor alleles were associated with a significantly increased risk for OSAS compared to the controls (P ˂ 0.05 for all). Furthermore, ATA haplotype frequency was significantly higher in the study group compared to the control group, but the GCC haplotype frequency was lower (P = 0.0001 and P = 0.0001). As indicated in MDR analysis, combinations of IL-10 gene were associated with OSAS in single-, double-, and triple-locus analyses.

CONCLUSION

The prevalences of the IL-10 gene promoter polymorphisms were different in OSAS patients and the controls in Turkish population. IL-10 gene polymorphisms may lead to altered inflammatory cascade, which might contribute to OSAS. Further studies on larger cohorts are needed to validate our findings.

Reduced systemic levels of IL-10 are associated with the severity of obstructive sleep apnea and insulin resistance in morbidly obese humans

Obstructive sleep apnea (OSA) has been related to elevation of inflammatory cytokines and development of insulin resistance in morbidly obese (MO) subjects. However, it is still unclear whether the systemic concentration of anti-inflammatory mediators is also affected in MO subjects directly related to the severity of OSA and level of insulin resistance. Normal weight and MO subjects were subjected to overnight polysomnography in order to establish the severity of OSA, according to the apnea-hypopnea index (AHI). Blood samples were obtained for estimation of total cholesterol and triglycerides, insulin, glucose, insulin resistance, tumor necrosis factor alpha (TNF-α), interleukin 12 (IL12), and interleukin 10 (IL-10). Serum levels of IL-10 were significantly lower in MO subjects with OSA than in MO and control individuals without OSA. Besides being inversely associated with serum TNF-α and IL-12, decreased IL-10 levels were significantly related to increased AHI, hyperinsulinemia, and insulin resistance. Serum IL-10 is significantly reduced in morbidly obese subjects with severe OSA while also showing a clear relationship with a state of hyperinsulinemia and insulin resistance probably regardless of obesity in the present sample. It may be of potential clinical interest to identify the stimulatory mechanisms of IL-10 in obese individuals with OSA.

Serum inflammatory markers in obstructive sleep apnea: a meta-analysis

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) has been linked to and is associated with increased cardiovascular and cerebrovascular morbidity. Ongoing inflammatory responses play an important role in this association. Multiple small size studies addressing the profile of the inflammatory markers in OSA are available therefore we performed a meta-analysis.

METHODS

Systematic review of medical literature was conducted using PubMed, Cochrane, and EMBASE databases from 1968 to 2011 by utilizing the key words obstructive sleep apnea, C-Reactive protein, tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), interleukin 8 (IL-8), intercellular adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM) and Selectins. Inclusion criteria were: full text English articles; studies with adult population; reported values for at least one of the markers of interest; with at least two separate groups (subjects with OSA and control group); OSA was defined as AHI of ≥ 5/h.

RESULTS

Five hundred and twelve studies were reviewed for inclusion with 51 studies pooled for analysis (30 studies for CRP, 19 studies for TNF-α, 8 studies for ICAM, 18 studies for IL-6, six studies for VCAM and 5 studies for Selectins). The levels of inflammatory markers were higher in patients with OSA compared to control group. Standardized pooled Mean differences were calculated to be 1.77 for CRP, 1.03 for TNF-α, 2.16 for IL-6, 4.22 for IL-8, 2.93 for ICAM, 1.45 for Selectins and 2.08 for VCAM.

CONCLUSIONS

In this meta-analysis, the levels of systemic inflammatory markers were found to be higher in OSA patients compared to control subjects.

Leptin: a biomarker for sleep disorders?

Leptin, a pleiotropic protein hormone produced mainly by fat cells, regulates metabolic activity and many other physiological functions. The intrinsic circadian rhythm of blood leptin is modulated by gender, development, feeding, fasting, sleep, obesity, and endocrine disorders. Hyperleptinemia is implicated in leptin resistance. To determine the specificity and sensitivity of leptin concentrations in sleep disorders, we summarize here the alterations of leptin in four conditions in animal and human studies: short duration of sleep, sleep fragmentation, obstructive sleep apnea (OSA), and after use of continuous positive airway pressure (CPAP) to treat OSA. The presence and causes of contradictory findings are discussed. Though sustained insufficient sleep lowers fasting blood leptin and therefore probably contributes to increased appetite, obesity and OSA independently result in hyperleptinemia. Successful treatment of OSA by CPAP is predicted to decrease hyperleptinemia, making leptin an ancillary biomarker for treatment efficacy. Current controversies also call for translational studies to determine how sleep disorders regulate leptin homeostasis and how the information can be used to improve sleep treatment.

Circulating adhesion molecules in obstructive sleep apnea and cardiovascular disease

Over 20 years of evidence indicates a strong association between obstructive sleep apnea (OSA) and cardiovascular disease. Although inflammatory processes have been heavily implicated as an important link between the two, the mechanism for this has not been conclusively established. Atherosclerosis may be one of the mechanisms linking OSA to cardiovascular morbidity. This review addresses the role of circulating adhesion molecules in patients with OSA, and how these may be part of the link between cardiovascular disease and OSA. There is evidence for the role of adhesion molecules in cardiovascular disease risk. Some studies, albeit with small sample sizes, also show higher levels of adhesion molecules in patients with OSA compared to controls. There are also studies that show that levels of adhesion molecules diminish with continuous positive airway pressure therapy. Limitations of these studies include small sample sizes, cross-sectional sampling, and inconsistent control for confounding variables known to influence adhesion molecule levels. There are potential novel therapies to reduce circulating adhesion molecules in patients with OSA to diminish cardiovascular disease. Understanding the role of cell adhesion molecules generated in OSA will help elucidate one mechanistic link to cardiovascular disease in patients with OSA.

The treg/th17 imbalance in patients with obstructive sleep apnoea syndrome

Obstructive sleep apnoea syndrome (OSAS) is a chronic inflammatory disease regulated by T lymphocytes. Our purpose is to assess the pattern of Th17 cells and CD4⁺CD25⁺Foxp3⁺ regulatory T (Treg) cells in peripheral blood of patients with OSAS. Fourty-four OSAS men and 20 healthy volunteers were enrolled. Twenty-three patients were classified into mild to moderate group and 21 cases were classified into severe group according to the severity of OSAS. We detected the frequencies of Th17 and Treg and related serum cytokines secretion and expressions of key transcription factors. OSAS patients revealed significant increase in peripheral Th17 number, Th17-related cytokines (IL-17 and IL-6), and RORγt mRNA levels. They also presented a significant decrease in Treg number, Treg-related cytokines (TGF-β₁), and Foxp3 mRNA levels as compared with normal persons. As a result, the Th17/Treg ratios were markedly more upregulated in OSAS patients than those in control group. Furthermore, the Th17/Treg ratio was positively related to the severity of OSAS and serum levels of C-reactive protein. The development of OSAS may be associated with peripheral Th17/Treg imbalance and characterized by a proinflammatory cytokine microenvironment. These results opened an alternative explanation for the substantial activation of immune cells in OSAS and the development of related complications.

One's sex, sleep, and posttraumatic stress disorder

Women are approximately twice as likely as men to develop posttraumatic stress disorder (PTSD) after trauma exposure. Mechanisms underlying this difference are not well understood. Although sleep is recognized to have a critical role in PTSD and physical and psychological health more generally, research into the role of sleep in PTSD sex differences has been only recent. In this article, we review both animal and human studies relevant to sex differences in sleep and PTSD with an emphasis on the roles of sex hormones. Sleep impairment including insomnia, trauma-related nightmares, and rapid-eye-movement (REM) sleep fragmentation has been observed in individuals with chronic and developing PTSD, suggesting that sleep impairment is a characteristic of PTSD and a risk factor for its development. Preliminary findings suggested sex specific patterns of sleep alterations in developing and established PTSD. Sleep maintenance impairment in the aftermath of trauma was observed in women who subsequently developed PTSD, and greater REM sleep fragmentation soon after trauma was associated with developing PTSD in both sexes. In chronic PTSD, reduced deep sleep has been found only in men, and impaired sleep initiation and maintenance with PTSD have been found in both sexes. A limited number of studies with small samples have shown that sex hormones and their fluctuations over the menstrual cycle influenced sleep as well as fear extinction, a process hypothesized to be critical to the pathogenesis of PTSD. To further elucidate the possible relationship between the sex specific patterns of PTSD-related sleep alterations and the sexually dimorphic risk for PTSD, future studies with larger samples should comprehensively examine effects of sex hormones and the menstrual cycle on sleep responses to trauma and the risk/resilience for PTSD utilizing various methodologies including fear conditioning and extinction paradigms and animal models.

Influence of CPAP treatment on airway and systemic inflammation in OSAS patients

AIM

Obstructive sleep apnea syndrome (OSAS) is characterized by recurrent respiratory disorders in the upper airways during sleep. Although continuous positive airway pressure (CPAP) has been accepted to be the most effective treatment for OSAS, its role on inflammation remains debatable. In this study, our aim was to examine the influence of 3 months of CPAP treatment on tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), 8-isoprostane, and peroxynitrite levels in exhaled breathing condensates (EBC) and serum.

METHODS

Thirty-five patients who were newly diagnosed as moderate or severe OSAS with full night polysomnography and used CPAP therapy regularly for 3 months were included in the study. Polysomnography, spirometric tests, fasting blood samples, and EBC were ascertained on entry into the study and after 3 months of treatment. All patients were assessed monthly for treatment adherence and side effects.

RESULTS

We found that all polysomnographic parameters were normalized after CPAP therapy in the control polysomnogram. Also, all markers in EBC and nitrotyrosine and 8-isoprostane levels in serum were decreased significantly with CPAP treatment. Sedimentation rate, C-reactive protein, IL-6, and TNF-α remained unchanged in serum after treatment. We found that baseline nitrotyrosine levels were significantly correlated with apnea-hypopnea index, oxygen desaturation index, and percent time in SpO2 < 90 % (p < 0.01).

CONCLUSIONS

CPAP therapy has primarily a relevant impact on airways, and nitrotyrosine levels correlated well with severity of OSAS. This treatment decreases both inflammation and oxidative stress levels in airways in OSAS patients. Also, this treatment helps to decrease systemic oxidative stress levels in serum.

Sleep-disordered breathing in multiple sclerosis

BACKGROUND

The objectives of this cross-sectional study were to assess the prevalence and severity of sleep apnea in patients with multiple sclerosis (MS) referred for overnight polysomnography (PSG) and to explore the radiographic and clinical features that might signal risk for undiagnosed sleep apnea.

METHODS

Apnea-hypopnea (AHI) and central apnea indices (CAI) from laboratory-based PSG among 48 patients with MS were compared with those of group A, 84 sleep laboratory-referred patients without MS matched for age, gender, and body mass index; and group B, a separate group of 48 randomly selected, referred patients.

RESULTS

Mean AHI was higher among patients with MS than among control groups A or B (2-way analysis of variance and multiple linear regression, p = 0.0011 and 0.0118, respectively). Median and mean CAI were also increased among patients with MS in comparison to control groups (Wilcoxon signed rank and multiple linear regression, p = 0.0064 and 0.0027, respectively). Among MS patients with available data, those with evidence of brainstem involvement, compared with groups A and B, showed particularly robust differences in AHI (p = 0.0060 and 0.0016) and CAI (p = 0.0215 and <0.0001). In contrast, MS patients without brainstem involvement, compared with groups A and B, showed diminished differences in AHI, and CAI did not significantly differ among groups.

CONCLUSIONS

These data suggest a predisposition for obstructive sleep apnea and accompanying central apneas among patients with MS, particularly among those with brainstem involvement.

Dietary conjugated nonadecadienoic acid prevents adult-onset obesity in nescient basic helix-loop-helix 2 knockout mice

Conjugated linoleic acid (CLA) has been extensively studied during the last two decades with regard to its effects on controlling body composition. As a cognate to CLA, conjugated nonadecadienoic acid (CNA) has been previously reported to reduce body fat more effectively than CLA. However, it is not known whether CNA supplementation can influence adult-onset obesity. Thus, the purpose of this study was to evaluate the effects of dietary CNA on the prevention of adult-onset inactivity-induced obesity using nescient basic helix-loop-helix 2 knockout (N2KO) mice. CNA supplementation at 0.1 w/w% level starting in the preobese state significantly prevented the reduction of voluntary movement and the increase in weight gain in N2KO mice during the experimental period compared to wild-type animals. In both wild-type and N2KO mice, respiratory exchange ratio was significantly reduced by CNA treatment during light and dark cycles, and dietary CNA significantly increased energy expenditure in N2KO mice. Selected gene expression profiles in white adipose tissue, muscle or liver showed a beneficial action of CNA on lipid metabolism and energy expenditure. These findings suggest that CNA could prevent adult-onset obesity by enhancing voluntary activity and energy expenditure in N2KO mice.

The association between severity of obstructive sleep apnea and prevalence of Hashimoto's thyroiditis

Obstructive sleep apnea (OSA) has long been suggested to increase the risk of development of autoimmune diseases. We investigated the prevalence of Hashimoto's thyroiditis (HT) in 245 euthyroid individuals, who were suspected of having OSA. After polysomnography, subjects were grouped according to apnea-hypopnea index (AHI) consecutively as controls (n=27F/32M, AHI<5), mild-OSA (n=22F/37M, 5≤AHI<15), moderate-OSA (n=23F/38M, 15≤AHI<30) and severe-OSA (n=30F/36M, AHI≥30). Diagnosis of HT based on thyroid ultrasound and positivity of serum anti-thyroglobulin (anti-TG) and anti-thyroid peroxidase (anti-TPO) antibodies. Hashimoto's thyroiditis was diagnosed in 32.2% of controls and in 46.8% of all OSA patients (p=0.03). Severe-OSA patients had the highest HT frequency (51.5%) compared to controls (p=0.02), mild-OSA (42.3%, p=0.03) and moderate-OSA (45.9%, p=0.05) groups. Forty-two of control subjects (71.2%) were negative for both of the anti-TPO and anti-TG, whereas 99 (53.2%) of OSA subjects were positive at least for one of them (p=0.01). HT was detected in 62% of females, 29% of males (p<0.001). Severe female OSA patients had the highest HT prevalence (73.3%), while male control subjects had the lowest (18.7%) among all groups (p<0.001). There was no significant correlation between thyroid volume and severity of OSA but isthmus thickness was significantly correlated to AHI (p<0.01, r=0.22). In conclusion, OSA patients presented higher HT prevalence parallel to severity of OSA, especially among women. These results may lead to further investigations about relation between OSA and auto-immune thyroiditis and to development of screening schemas for severe-OSA patients for early diagnosis of HT before development of hypothyroidism.

Markers of Sleep Disordered Breathing and Diabetes Mellitus in a Multiethnic Sample of US Adults: Results from the National Health and Nutrition Examination Survey (2005-2008)

We examined gender and ethnic differences in the association between sleep disordered breathing (SDB) and diabetes among 6,522 participants aged ≥20 years from the National Health and Nutrition Examination Survey 2005-08. SDB severity was defined based on an additive summary score including sleep duration, snoring, snorting, and daytime sleepiness. We found that the summary SDB score was significantly associated with diabetes after adjusting for potential confounders in the whole population. Compared to those without any sleep disturbance, the multivariable odds ratio (OR) (95% confidence interval (CI)) of diabetes among those with ≥3 sleep disturbances was 2.04 (1.46-2.87). In sex-specific analyses, this association was significant only in women (OR (95% CI) = 3.68 (2.01-6.72)) but not in men (1.10 (0.59-2.04)), P-interaction = 0.01. However, there were no ethnic differences in this association, P-interaction = 0.7. In a nationally representative sample of US adults, SDB was independently associated with diabetes only in women, but not in men.

Night work and inflammatory markers

BACKGROUND

Various adverse health effects associated with shift work have been documented in the medical literature. These include increased risk of cardiovascular disorders, cerebrovascular disorders, and mortality. Sleep deprivation has been shown to be associated with an elevation in inflammatory makers such as interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP). It is hypothesized that the increased risk of many disorders associated with shift work may be due to inflammatory processes resulting from sleep deprivation. The purpose of this study was to investigate the relationship between night work and inflammatory markers.

MATERIALS AND METHODS

Fifty workers were selected according to the specified inclusion and exclusion criteria and randomly assigned to one of two groups in a cross over study. The 25 workers in group 1 were scheduled to work the following consecutive shifts: three day shifts, one day off, and three night shifts. Group 2 were scheduled to work the following consecutive shifts: three night shifts, one day off, and three day shifts. Blood samples were obtained between 7:A.M. and 8:A.M. after the periods of day work and night work and tested for inflammatory markers.

STATISTICAL ANALYSES

SPSS 11.5 and S-data were used to analyze data using the Student's t-test and paired t-test.

RESULTS

There was a statistically significant increase in IL-6, CRP, white blood cells, neutrophils, lymphocytes, and platelets following night work compared with day work. TNF-α was increased but it was not statistically significant, and also the change in monocyte counts was not significant.

CONCLUSION

This study demonstrated an increase in inflammatory markers following night work, as reported in several pervious studies on sleep deprivation. No significant changes in monocyte count can be justified by the results of a study which showed that the elevation in blood levels of inflammatory markers is due to increase in gene expression, not in monocyte counts.

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

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.

Association of osteopontin and tumor necrosis factor-α levels with insulin resistance in obese patients with obstructive sleep apnea syndrome

OBJECTIVE

The aims of this study were to compare the tumor necrosis factor (TNF)-α and osteopontin levels, to identify the relationship between insulin resistance (IR) and osteopontin levels in obese patients with and without obstructive sleep apnea syndrome (OSAS).

METHOD

The study population included 62 obese patients (35 males, 27 females) with OSAS and was compared with 26 obese patients (16 males, 10 females) without OSAS as a control group. Polysomnographic evaluation, spirometric tests and arterial blood gas sampling were performed on the obese patients with OSAS. Plasma levels of TNF-α and osteopontin were measured by enzyme-linked immunosorbent assays during the process. IR was estimated using the homeostasis model assessment (HOMA).

RESULTS

Mean plasma levels of fasting glucose, insulin, HOMA, liver function test, hematocrit, leukocyte, TSH, free T4, fibrinogen, TNF-α, and osteopontin were similar in the 2 groups. In patients with OSAS, mean osteopontin levels were positively correlated with mean fasting insulin levels (r=0.306, p=0.01), HOMA (r=0.299, p=0.01), apnea-hypopnea index (r=0.377, p=0.03) and Epworth Sleepiness Scale (r=0.299, p=0.01). However, mean TNF-α levels were negatively correlated with Epworth Sleepiness Scale (r=-0.298, p=0.01) in the patients with OSAS.

CONCLUSIONS

It was observed that TNF-α and osteopontin levels showed no difference between obese patients with and without OSAS. However, osteopontin levels increased with fasting insulin, IR, OSAS severity, and daytime sleepiness.

Diabetes and sleep: a complex cause-and-effect relationship

Strong associations of diabetes with sleep impairment have been frequently reported. In the present review, we discuss current evidence and hypotheses for how type 1 and type 2 diabetes mellitus are associated with sleep impairment. This association may be described as a vicious circle, where sleep disorders favor the development of type 2 diabetes or exacerbate the metabolic control of both types of diabetes, whereas diabetes itself, especially when associated with poor metabolic control, is often followed by sleep disorders. In this review, novel findings concerning the neuro-endocrine-metabolic mediation of the mentioned circle are highlighted. Understanding how this association occurs, the impact of sleep impairment on diabetes, and the impact of diabetes on the development or exacerbation of sleep disorders should lead to potential new therapeutic strategies for treating both conditions.

Sleep measures and morning plasma TNF-alpha levels in children with sleep-disordered breathing

BACKGROUND

Sleep disordered breathing in children is associated with severity-dependent increases in excessive daytime sleepiness (EDS). TNF-alpha is an inflammatory cytokine that has been implicated in EDS. Since, at any given level of apnea-hypopnea index, there is significant variability in EDS, we hypothesized that morning tumor necrosis factor (TNF)-alpha plasma levels may provide a biologic correlate of EDS.

METHODS

Children being evaluated for sleep disordered breathing underwent a blood draw after nocturnal polysomnography, and TNF-alpha plasma concentrations were assayed using ELISA. In a subset of 15 children with sleep disordered breathing and in 15 matched control subjects, whole blood cultures in the presence of lipopolysaccharide and Multiple Sleep Latency Test were conducted. Furthermore, 22 children with obstructive sleep apnea had TNF-alpha levels assayed and underwent nocturnal polysomnography and Multiple Sleep Latency Test before and after adenotonsillectomy.

RESULTS

In 298 children, morning TNF-alpha levels were globally increased in the presence of obstructive sleep apnea, particularly in more severe cases, and correlated with obstructive apnea-hypopnea index and sleep pressure score, a measure of respiratory-induced sleep fragmentation, but not with nadir Sa02. A stepwise logistic regression analysis revealed that sleep pressure score and body mass index accounted for 36.2% of the adjusted variance in TNF-alpha levels (P < 0.0001). Furthermore, multiple sleep latencies were correlated with whole blood culture-derived TNF-alpha levels (n = 15), and morning TNF-alpha levels decreased after adenotonsillectomy in 22 children.

CONCLUSIONS

TNF-alpha levels are increased in pediatric obstructive sleep apnea, are primarily driven by sleep fragmentation and body mass index, and are closely associated with the degree of sleepiness, as measured by Multiple Sleep Latency Test. Furthermore, surgical treatment of obstructive sleep apnea results in significant reductions in TNF-alpha levels with reciprocal prolongations in sleep latency.

The activation of the inflammatory cytokines in overweight patients with mild obstructive sleep apnoea

It is widely accepted that obstructive sleep apnoea (OSA) is linked with cardiovascular diseases. The relationship is complex and remains still poorly understood. The presence of chronic systemic inflammation has been connected with pathogenesis of both OSA and cardiovascular diseases. While atherogenesis is believed to be a process of many years, little is known about the potential impact of the largest OSA subgroup, mild OSA, on the development of cardiovascular diseases. The aim of the present study was to assess whether untreated mild OSA is associated with an activation of inflammatory cytokine system. The adult study population consisted of two groups: 84 patients with mild OSA [apnoea-hypopnoea index (AHI) 5-15 h(-1)] and 40 controls (AHI <5 h(-1)). Serum concentrations of pro- and anti-inflammatory cytokines were measured before any interventions. After adjustments for age, sex, body mass index, fat percentage, most important cardiometabolic and inflammatory diseases, and non-steroidal anti-inflammatory medication, the mean level of tumour necrosis factor-alpha was significantly elevated (1.54 versus 1.17 pg mL(-1), P = 0.004), whereas the level of interleukin-1 beta (IL-1 beta) was reduced (0.19 versus 0.23 pg mL(-1), P = 0.004) in patients with mild OSA compared with controls. The concentrations of the protective anti-inflammatory cytokines, interleukin-10 (1.28 versus 0.70 pg mL(-1), P < 0.001) and interleukin-1 receptor antagonist (478 versus 330 pg mL(-1), P = 0.003) were elevated in the OSA group. The concentrations of C-reactive protein increased, but IL-1 beta decreased along with the increase of AHI. Mild OSA was found to be associated not only with the activation of the pro-inflammatory, but also with the anti-inflammatory systems.

Cytokine production from peripheral blood mononuclear cells and polymorphonuclear leukocytes in patients studied for suspected obstructive sleep apnea

PURPOSE

The relationship between obstructive sleep apnea (OSA) and atherosclerosis-related inflammation has been poorly investigated, particularly focusing on functional responses of immune cells playing a key role in atherogenesis and in comparison with control groups with similar cardiovascular risk factors which are known to be themselves associated with inflammation. We sought to determine cellular tumor necrosis factor-alpha (TNF-α) production from peripheral blood mononuclear cells (PBMCs) and interleukin (IL)-8 release from neutrophils (PMNs) in patients studied for suspected OSA.

METHODS

Thirty-six consecutive patients who underwent a nocturnal complete cardiorespiratory evaluation for suspected OSA were initially evaluated. Serum, PBMCs, and PMNs were isolated (at baseline and after 12 weeks) from patients with apnea-ipopnea index (AHI) >20 (OSA group, n = 16) and from control patients with AHI <5 (nonOSA group, n = 11). All patients continued the same pharmacological therapy for 12 weeks; the OSA group was additionally treated with nocturnal continuous positive-airway-pressure ventilation (cPAP).

RESULTS

The two groups had similar clinical characteristics (prevalence of hypertension, dyslipidemia, diabetes, and cardio-metabolic therapies) except for obesity. Resting and stimulated TNF-α production from PBMCs and IL-8 release from PMNs were similar in the two groups. Serum cytokines resulted within the normal range. In the OSA group, cPAP was not associated with changes in cellular responses.

CONCLUSIONS

In patients showing similar prevalence of major cardiovascular risk factors and cardio-metabolic therapies, differing for the presence or absence of OSA, cytokine productions from PBMC and PMN were similar and were not modified during cPAP therapy. Studies designed to investigate OSA-associated inflammation should carefully match the control group subjects.

Obesity and upper airway control during sleep

Mechanisms linking obesity with upper airway dysfunction in obstructive sleep apnea are reviewed. Obstructive sleep apnea is due to alterations in upper airway anatomy and neuromuscular control. Upper airway structural alterations in obesity are related to adipose deposition around the pharynx, which can increase its collapsibility or critical pressure (P(crit)). In addition, obesity and, particularly, central adiposity lead to reductions in resting lung volume, resulting in loss of caudal traction on upper airway structures and parallel increases in pharyngeal collapsibility. Metabolic and humoral factors that promote central adiposity may contribute to these alterations in upper airway mechanical function and increase sleep apnea susceptibility. In contrast, neural responses to upper airway obstruction can mitigate these mechanical loads and restore pharyngeal patency during sleep. Current evidence suggests that these responses can improve with weight loss. Improvements in these neural responses with weight loss may be related to a decline in systemic and local pharyngeal concentrations of specific inflammatory mediators with somnogenic effects.

Mechanisms of intermittent hypoxia induced hypertension

Exposing rodents to brief episodes of hypoxia mimics the hypoxemia and the cardiovascular and metabolic effects observed in patients with obstructive sleep apnoea (OSA), a condition that affects between 5% and 20% of the population. Apart from daytime sleepiness, OSA is associated with a high incidence of systemic and pulmonary hypertension, peripheral vascular disease, stroke and sudden cardiac death. The development of animal models to study sleep apnoea has provided convincing evidence that recurrent exposure to intermittent hypoxia (IH) has significant vascular and haemodynamic impact that explain much of the cardiovascular morbidity and mortality observed in patients with sleep apnoea. However, the molecular and cellular mechanisms of how IH causes these changes is unclear and under investigation. This review focuses on the most recent findings addressing these mechanisms. It includes a discussion of the contribution of the nervous system, circulating and vascular factors, inflammatory mediators and transcription factors to IH-induced cardiovascular disease. It also highlights the importance of reactive oxygen species as a primary mediator of the systemic and pulmonary hypertension that develops in response to exposure to IH.

Effect of continuous positive airway pressure therapy on aortic stiffness in patients with obstructive sleep apnea syndrome

OBJECTIVE

The most significant complications seen in patients with obstructive sleep apnea syndrome (OSAS) are associated with the cardiovascular system. The present study assessed aortic stiffness in patients with OSAS and evaluated the effect of continuous positive airway pressure (CPAP) therapy on aortic stiffness.

METHOD

Twenty-four patients with newly diagnosed, previously untreated, moderate or severe OSAS (apnea-hypopnea index > 15) and a control group of 17 healthy patients were included in the study. M-mode recordings of the ascending aorta were taken from the parasternal long axis by echocardiograhy, and systolic and diastolic diameters of the aorta were measured. Aortic elastic parameters, aortic strain, and distensibility were calculated. Measurements were repeated after 6 months of CPAP therapy in patients with OSAS and were compared with baseline values.

RESULTS

In patients with OSAS, compared with the control group, aortic strain (6.7%+/- 2.1% vs. 12.4%+/- 3.1%; P < 0.001) and aortic distensibility (2.8 +/- 0.9 x 10(-6) cm(2) dyn(-1) vs. 5.5 +/- 1.7 x 10(-6) cm(2) dyn(-1); P < 0.001) were evidently lower, and there was a significant correlation between aortic elastic parameters and AHI. After a 6-month course of CPAP therapy, significant increases were observed in aortic strain (6.1%+/- 1.5% vs. 7.3%+/- 1.7%; P < 0.001) and aortic distensibility (2.5 +/- 0.7 x 10(-6) cm(2) dyn(-1) vs. 3.1 +/- 0.9 x 10(-6) cm(2) dyn(-1); P < 0.001) in patients with OSAS.

CONCLUSION

Aortic strain and distensibility were lower in patients with OSAS than in control patients, and CPAP treatment provided improvement in aortic elastic parameters.

Long-term effect of continuous positive airway pressure therapy on inflammation markers of patients with obstructive sleep apnea syndrome

STUDY OBJECTIVES

Several lines of evidence suggest immune system derangement in obstructive sleep apnea syndrome (OSAS) patients. However, no data exist on the long-term effect of continuous positive airway pressure (CPAP) treatment on systemic immunity. Hence, we sought to evaluate this effect on various immunological parameters in OSAS patients.

DESIGN

Prospective case series.

SETTING

Sleep unit of a general hospital.

PATIENTS

Newly-diagnosed, nonsmoking, otherwise healthy OSAS male patients (n = 52) were evaluated on diagnosis and 6 months after CPAP treatment. According to compliance to CPAP use at 6-month follow-up, they were divided into 2 groups: group A (n = 32): good compliance (mean CPAP use > or = 4 h/night); and group B (n = 20): poor compliance (mean CPAP use < 4 h/night).

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Blood samples were obtained at baseline and at the 6-month follow-up. Percentage and absolute count of lymphocyte subsets (by flow cytometry), serum TNF-alpha, IL-6, and uric acid levels were measured. No differences were recorded regarding the baseline anthropometric or sleep characteristics of the 2 groups. In group A, a significant decrease in the absolute count of total lymphocytes (P = 0.003), and of CD4+ cells (P = 0.001), and a decrease in TNF-alpha levels (P = 0.001) and uric acid levels (P < 0.001) was observed after CPAP application. On the contrary, no alterations occurred in any of the tested parameters in group B patients.

CONCLUSIONS

The selective reduction of soluble and cellular immune response factors only in those OSAS patients who exhibited good compliance to CPAP therapy provides further evidence for an ongoing systemic immune process in OSAS.

Cerebrovascular Diseases and Sleep-Disordered Breathing

Sleep-disordered breathing (SDB) is more probably the cause rather than the consequence of stroke because: apneas are essentially obstructive rather than central, the frequency of SDB is not different between transient ischemic attack and cerebral infarction; and previous excessive daytime sleepiness is significantly more frequent among stroke patients with SDB than those without. The presence of SDB in stroke patients could lead to a poor outcome. Pathophysiological relationships between strokes and SDB are multiple. Experimental and clinical studies have shown that both short- and long-term factors may play a role in increasing the susceptibility to stroke in patients with obstructive sleep apnea syndrome. The former include changes in cerebral hemodynamics, hematologic alterations, and cardiocirculatory dysfunctions that typically and repeatedly occur during apnea episodes and also may persist during wakefulness. Regarding long-term factors, some changes in the anatomical characteristics of carotid arteries wall have been recognized in SDB patients. This finding seems to suggest that the link between SDB and cerebrovascular disease might be explained, at least in part, by an increase in the progression of the atherosclerosis process involving cerebral vessels. There are several practical implications from the demonstrated significant role of sleep apnea in increasing the predisposition to developing stroke. Specific investigation is fundamental in the presence of a clinical suspect of SDB, especially in patients with history of transient ischemic attacks and stroke. Specific treatment of SDB may reduce the possibility of further cerebrovascular disturbances.

Obstructive sleep breathing disorders

Obstructive sleep apnea (OSA) is increasingly recognized in children. There is accumulating robust evidence to support early diagnosis and treatment of this condition. The purpose of this review is to provide an update on the epidemiology, clinical features, complications, and treatment of childhood OSA. The authors have also proposed an easy-to-follow flowchart on the management of children with snoring or sleep disturbance for clinical use by busy pediatricians.

The roles of TNF-alpha and the soluble TNF receptor I on sleep architecture in OSA

Objective

Patients with obstructive sleep apnea (OSA) have been described to have increased levels of inflammatory cytokines (particularly TNF-α) and have severely disturbed sleep architecture. Serum inflammatory markers, even in normal individuals, have been associated with abnormal sleep architecture. Not much is known about the role the TNF receptor plays in the inflammation of OSA nor if it is associated with changes in sleep architecture or arousals during the night. We hypothesized that the TNF receptor might play an important role in the inflammation as well as sleep architecture changes in patients with OSA.

Design

Thirty-six patients with diagnosed (AHI > 15) but untreated OSA were enrolled in this study. Baseline polysomnograms as well as TNF-α and soluble TNF receptor I (sTNF-RI) serum levels were obtained on all patients. We evaluated the association between serum levels of TNF-α and sTNF-RI with various polysomongraphic characteristics, including sleep stages and EEG arousals.

Results

sTNF-RI levels were significantly correlated with snore arousals (r value 0.449, p value 0.009), spontaneous movement arousals (r value 0.378, p value 0.025), and periodic limb movement arousals (r value 0.460, p value 0.008). No statistically significant correlations were observed with TNF-α to any polysomnographic variables. To control for statistical significance with multiple comparisons, a MANOVA was performed with TNF-α and sTNF-RI as dependent variables and sleep architecture measures and arousals as independent variables. The model for sTNF-RI was statistically significant (F value 2.604, p value 0.03), whereas the model for TNF-α was not, suggesting sleep quality significantly affects sTNF-RI. Hierarchal linear regression analysis demonstrated that sTNF-RI was independently associated with spontaneous movement arousal index scores after controlling for age, body mass index, and sleep apnea severity.

Conclusions

These findings suggest that sTNF-RI is associated with arousals during sleep, but not with other measures in patients with OSA.

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.

Effects of continuous positive airway pressure therapy on right ventricular function assessment by tissue Doppler imaging in patients with obstructive sleep apnea syndrome

OBJECTIVES

The effects of continuous positive airway pressure (CPAP) therapy on right ventricular (RV) function in patients with obstructive sleep apnea syndrome (OSAS) has not been previously studied by tissue Doppler imaging (TDI). The aim of this study was to assess RV function using TDI in patients with OSAS before and after CPAP therapy.

METHODS

Twenty-eight patients with newly diagnosed OSAS in the absence of any confounding factors and 18 controls were included in this study. The peak systolic velocity (S'm), early (E'm) and late (A'm) diastolic myocardial peak velocities at tricuspid lateral annulus, isovolumic acceleration (IVA), myocardial precontraction time (PCT'm), myocardial contraction time (CT'm), and myocardial relaxation time (RT'm) were measured. All echocardiographic parameters were calculated 6 months after CPAP therapy.

RESULTS

The RV diastolic parameters such as E'm velocity and E'm-to-A'm ratio were significantly lower, RT'm was significantly prolonged, A'm velocity was similar in patients with OSAS compared to controls; and the RV systolic parameters such as IVA and CT'm were significantly lower and S'm was similar in patients with OSAS compared to controls. At the end of the treatment, 20 of 28 patients were compliant with CPAP therapy. E'm velocity, E'm-to-A'm ratio, IVA, and CT'm increased, PCT'm, PCT'm-to-CT'm ratio, and RT'm decreased significantly after therapy, whereas S'm velocity and A'm velocity did not change after CPAP treatment in the compliant patients.

CONCLUSION

OSAS is associated with RV systolic and diastolic dysfunction, and 6 months of CPAP therapy improves the RV systolic and diastolic dysfunction.

Inflammatory Cytokines and Childhood Obstructive Sleep Apnoea

Objective: To evaluate serum cytokine concentrations in children with and without obstructive sleep apnoea (OSA) and to investigate the effects of OSA treatment on cytokines. Materials and Methods: Consecutive children with habitual snoring and symptoms suggestive of OSA were recruited. They completed a sleep apnoea symptom questionnaire, underwent physical examination and overnight polysomnography (PSG). OSA was diagnosed if obstructive apnoea index (OAI) >1. A blood sample was collected for analysis of IL-6, IL-8, and TNF-α after PSG. Results: One hundred forty-two children (97 males) with a median (IQR) age of 11.1 years (9.0-12.8) were recruited. The commonest presenting symptoms were nocturnal mouth breathing, prone sleeping position and poor attention at school. Forty-seven children were found to have OSA and they had higher serum IL-6 [0.1 (0.1-0.4) vs 0.1 (0.1-0.1) pg/mL, P = 0.001] and IL-8 [1.7 (1.0-2.3) vs 1.3 (0.9-1.7) pg/mL, P = 0.029] concentrations compared to their non-OSA counterparts. Multiple regression analysis indicated that OAI was significantly associated with both IL-6 (r = 0.351, P <0.001) and IL-8 (r = 0.266, P = 0.002). Sixteen children underwent treatment and there was significant reduction in mean (SD) serum IL-8 after intervention [pre vs post levels of 1.9 (1.0) vs 1.1 (0.6) pg/mL, P = 0.001] independent of weight loss. Conclusion: Children with OSA had elevated levels of pro-inflammatory cytokines that normalised following treatment suggesting that the inflammatory response is potentially reversible. Early detection and intervention may be beneficial. Key words: Interleukin 6, Interleukin 8, Polysomnography, Tumour necrosis factor

Sleep-disordered breathing and type 2 diabetes: a report from the International Diabetes Federation Taskforce on Epidemiology and Prevention

Sleep-disordered breathing (SDB) has been associated with insulin resistance and glucose intolerance, and is frequently found in people with type 2 diabetes. SDB not only causes poor sleep quality and daytime sleepiness, but has clinical consequences, including hypertension and increased risk of cardiovascular disease. In addition to supporting the need for further research into the links between SDB and diabetes, the International Diabetes Federation Taskforce on Epidemiology and Prevention strongly recommends that health professionals working in both type 2 diabetes and SDB adopt clinical practices to ensure that a patient presenting with one condition is considered for the other.

Cytokine mRNA induction by interleukin-1beta or tumor necrosis factor alpha in vitro and in vivo

Hypothalamic and cortical mRNA levels for cytokines such as interleukin-1beta (IL1beta), tumor necrosis factor alpha (TNFalpha), nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) are impacted by systemic treatments of IL1beta and TNFalpha. To investigate the time course of the effects of IL1beta and TNFalpha on hypothalamic and cortical cytokine gene expression, we measured mRNA levels for IL1beta, TNFalpha, interleukin-6 (IL-6), interleukin-10 (IL-10), IL1 receptor 1, BDNF, NGF, and glutamate decarboxylase-67 in vitro using hypothalamic and cortical primary cultures. IL1beta and TNFalpha mRNA levels increased significantly in a dose-dependent fashion after exposure to either IL1beta or TNFalpha. IL1beta increased IL1beta mRNA in both the hypothalamic and cortical cultures after 2-6 h while TNFalpha mRNA increased significantly within 30 min and continued to rise up to 2-6 h. Most of the other mRNAs showed significant changes independent of dose in vitro. In vivo, intracerebroventricular (icv) injection of IL1beta or TNFalpha also significantly increased IL1beta, TNFalpha and IL6 mRNA levels in the hypothalamus and cortex. IL1beta icv, but not TNFalpha, increased NGF mRNA levels in both these areas. Results support the hypothesis that centrally active doses of IL1beta and TNFalpha enhance their own mRNA levels as well as affect mRNA levels for other neuronal growth factors.

Structural equation modeling of sleep apnea, inflammation, and metabolic dysfunction in children

Obstructive sleep apnea (OSA), often concomitant with obesity, increases the risk for the metabolic syndrome. One mechanism that may participate in this association is upregulation of inflammatory pathways. We used structural equation modeling to assess the interrelations between childhood obesity, OSA, inflammation, and metabolic dysfunction. One hundred and eighty-four children (127 boys, mean age: 8.5 +/- 4.1 years) had height and weight measured, underwent overnight polysomnography and had fasting blood taken. The blood was analyzed for insulin, glucose, lipids, leptin, and cytokines [interferon (IFN)-gamma, granulocyte macrophage-colony stimulating factor, interleukin (IL)-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, tumor necrosis factor-alpha]. Structural equation modeling (SEM) was used to evaluate associations between the outcomes of interest including hypoxia, arousal (related to respiratory and spontaneous), obesity, metabolic dysfunction, and inflammatory markers. Two cytokine factors and one metabolic factor were derived for the SEM. These factors provided good fit in the structural equation model (chi(2)/df = 2.855; comparative fit index = 0.90, root mean squared error of approximation = 0.10) and all factor loadings were significantly different from zero (P < or = 0.01). Overall, our results indicate that while obesity (as measured by body mass index z-score) has a major influence on the metabolic dysfunction associated with OSA, arousal indices, and cytokine markers may also influence this association. Our results support the hypothesis that OSA is a contributor to the mechanisms that link sleep, systemic inflammation and insulin resistance, and show that the interrelations may begin in childhood.