PSGL-1: a novel immune checkpoint driving T-cell dysfunction in obstructive sleep apnea

Introduction

Although higher incidence of cancer represents a major burden for obstructive sleep apnea (OSA) patients, the molecular pathways driving this association are not completely understood. Recently, the adhesion receptor P-selectin glycoprotein-1 (PSGL 1) has been identified as a novel immune checkpoint, which are recognized major hallmarks in several types of cancer and have revolutionized cancer therapy.

Methods

The expression of PSGL-1 and its ligands VISTA and SIGLEC-5 was assessed in the leucocytes of OSA patients and control subjects exploring the role of intermittent hypoxia (IH) using in vitro models. In addition, PSGL-1 impact on T-cells function was evaluated by ex vivo models.

Results

Data showed PSGL-1 expression is upregulated in the T-lymphocytes from patients with severe OSA, indicating a relevant role of hypoxemia mediated by intermittent hypoxia. Besides, results suggest an inhibitory role of PSGL-1 on T-cell proliferation capacity. Finally, the expression of SIGLEC-5 but not VISTA was increased in monocytes from OSA patients, suggesting a regulatory role of intermittent hypoxia.

Discussion

In conclusion, PSGL-1 might constitute an additional immune checkpoint leading to T-cell dysfunction in OSA patients, contributing to the disruption of immune surveillance, which might provide biological plausibility to the higher incidence and aggressiveness of several tumors in these patients.

Identification of key genes and immune infiltration modulated by CPAP in obstructive sleep apnea by integrated bioinformatics analysis

Patients with obstructive sleep apnea (OSA) experience partial or complete upper airway collapses during sleep resulting in nocturnal hypoxia-normoxia cycling, and continuous positive airway pressure (CPAP) is the golden treatment for OSA. Nevertheless, the exact mechanisms of action, especially the transcriptome effect of CPAP on OSA patients, remain elusive. The goal of this study was to evaluate the longitudinal alterations in peripheral blood mononuclear cells transcriptome profiles of OSA patients in order to identify the hub gene and immune response. GSE133601 was downloaded from Gene Expression Omnibus (GEO). We identified black module via weighted gene co-expression network analysis (WGCNA), the genes in which were correlated significantly with the clinical trait of CPAP treatment. Finally, eleven hub genes (TRAV10, SNORA36A, RPL10, OBP2B, IGLV1-40, H2BC8, ESAM, DNASE1L3, CD22, ANK3, ACP3) were traced and used to construct a random forest model to predict therapeutic efficacy of CPAP in OSA with a good performance with AUC of 0.92. We further studied the immune cells infiltration in OSA patients with CIBERSORT, and monocytes were found to be related with the remission of OSA and partially correlated with the hub genes identified. In conclusion, these key genes and immune infiltration may be of great importance in the remission of OSA and related research of these genes may provide a new therapeutic target for OSA in the future.

The role of PD-L1 in the immune dysfunction that mediates hypoxia-induced multiple organ injury

Hypoxia is a pathological condition common to many diseases, although multiple organ injuries induced by hypoxia are often overlooked. There is increasing evidence to suggest that the hypoxic environment may activate innate immune cells and suppress adaptive immunity, further stimulating inflammation and inhibiting immunosurveillance. We found that dysfunctional immune regulation may aggravate hypoxia-induced tissue damage and contribute to secondary injury. Among the diverse mechanisms of hypoxia-induced immune dysfunction identified to date, the role of programmed death-ligand 1 (PD-L1) has recently attracted much attention. Besides leading to tumour immune evasion, PD-L1 has also been found to participate in the progression of the immune dysfunction which mediates hypoxia-induced multiple organ injury. In this review, we aimed to summarise the role of immune dysfunction in hypoxia-induced multiple organ injury, the effects of hypoxia on the cellular expression of PD-L1, and the effects of upregulated PD-L1 expression on immune regulation. Furthermore, we summarise the latest information pertaining to the involvement, diagnostic value, and therapeutic potential of immunosuppression induced by PD-L1 in various types of hypoxia-related diseases, including cancers, ischemic stroke, acute kidney injury, and obstructive sleep apnoea. Video Abstract.

Airways therapy of obstructive sleep apnea dramatically improves aberrant levels of soluble cytokines involved in autoimmune disease

Obstructive Sleep Apnea (OSA) damages the health of 35% of adult Americans. Disordered sleep results in increased risk of several autoimmune disorders, but the molecular links to autoimmunity are poorly understood. Herein, we identified four cytokines associated with autoimmune disease, whose median serum levels were significantly different for OSA patients receiving airways therapy, from the levels in untreated OSA patients, APRIL (5.2-fold lower, p = 3.5 × 10^-11), CD30 (1.6-fold higher, p = 7.7 × 10^-5), IFN-Alpha-2 (2.9-fold higher, p = 9.6 × 10^-14) and IL-2 (1.9-fold higher, p = 0.0003). Cytokine levels in airways treated patients were similar to the levels in control subjects. t-SNE and UMAP analysis of these high dimensional patient cytokine data identified only two groups, suggesting a similar global response for all four cytokines to airways therapy. Our findings suggest the levels of these four cytokines may be altered by disordered sleep and perhaps by chronic hypoxia. Therapeutic options are discussed.

Astragaloside IV ameliorates intermittent hypoxia-induced inflammatory dysfunction by suppressing MAPK/NF-κB signalling pathways in Beas-2B cells

PURPOSE

Intermittent hypoxia is a characteristic pathological change in obstructive sleep apnoea (OSA) that can initiate oxidative stress reaction and pro-inflammatory cytokine release. The purpose of this study was to assess the effect and protective mechanism of Astragaloside IV (AS-IV) in intermittent hypoxia-induced human lung epithelial Beas-2B cells.

METHODS

Human lung epithelial Beas-2B cells were exposed to intermittent hypoxia or normoxia in the absence or presence of AS-IV. MTT assay was performed to determine the cell viability. The levels of reactive oxygen species (ROS), lactate dehydrogenase (LDH), malonaldehyde (MDA), and superoxide dismutase (SOD) were measured to evaluate oxidative stress. The levels of cytokines interleukin (IL)-8, IL-1β, and IL-6 were evaluated by enzyme-linked immunosorbent assay and real-time PCR. The expression of Toll-like receptor 4 (TLR4), mitogen-activated protein kinase (MAPK), and nuclear transcription factor-kappa B (NF-κB) signalling pathways was analysed by western blot.

RESULTS

The results showed that AS-IV significantly reduced the levels of ROS, LDH, MDA, IL-8, IL-1β, and IL-6, and increased the level of SOD in intermittent hypoxia-induced Beas-2B cells. It also suppressed the phosphorylation of MAPKs, including P38, c-Jun N-terminal kinase and extracellular signal-regulated kinase, and inhibited the activation of the NF-κB signalling pathway by reducing the phosphorylation of IκBα and p65.

CONCLUSIONS

AS-IV attenuates inflammation and oxidative stress by inhibiting TLR4-mediated MAPK/NF-κB signalling pathways in intermittent hypoxia-induced Beas-2B cells.

Toll-Like Receptor-4-Mediated Inflammation is Involved in Intermittent Hypoxia-Induced Lung Injury

PURPOSE

Intermittent hypoxia (IH) is a recognized risk factor for multiple organs damage, resulting in lung injury. Its pathophysiology is still poorly understood. Toll-like receptor 4 (TLR4) signaling plays a critical role in host immune response to invading pathogen and non-infectious tissue injury. The role of TLR4-mediated inflammation in IH-induced lung injury was investigated in this study.

METHODS

Lean adult male TLR4-deficient (TLR4^-/-) mice and their controls (C57BL/6 mice) were exposed to either IH (FiO₂ 6-8% for 25 s, 150 s/cycle, 8 h/day) or air (normoxic mice) for 6 weeks. Animals were sacrificed after 6-week exposure, and the lung tissues were harvested for morphological and inflammatory analyses. The expression of TLR4 and nuclear factor kappa-B (NF-κB) P65 were examined by real-time quantitative polymerase chain reaction and immunohistochemical method. Serum cytokine levels of interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α) were analyzed by enzyme-linked immunosorbent assay.

RESULTS

IH induced morphological and inflammation changes in the lung. IH for 6 weeks induced higher expression of TLR4 (C57BL/6-N vs C57BL/6-IH, P < 0.05) and resulted in higher release of TNF-α, IL-6 (P < 0.05), and NF-κB P65 (P < 0.05). These alterations were remitted by TLR4 deletion.

CONCLUSIONS

TLR4-mediated inflammation plays an important role in the development of IH-induced lung injury in mice, possibly through mechanisms involving nuclear factor-κB. Targeting TLR4/NF-κB pathway could represent a further therapeutic option for sleep apnea patients.

TLR2 deficiency attenuated chronic intermittent hypoxia-induced neurocognitive deficits

Chronic intermittent hypoxia (CIH) is the main symptom of obstructive sleep apnea syndrome (OSAS) and causes neural damage and cognitive deficits via neuroinflammation. Toll-like receptors (TLRs), especially TLR2, play an important role in neuroinflammation. However, the mechanisms by which TLR2 participates in CIH-induced cognitive deficits remain unclear. In this study, wild-type (WT) and TLR2 knock out (KO) mice were exposed to CIH for 8 weeks, and their social novelty discrimination, spatial learning and memory were severely compromised. Additionally, seriously damaged neurons and abnormally activated glia were observed in the CA1 and dentate gyrus (DG) areas of the hippocampus. Mechanistically, knocking out the TLR2 gene significantly alleviated these pathological changes and improved the behavioral performance. Together, these findings demonstrate that the TLR2-MyD88 signaling pathway might play an important role in CIH-induced cognitive deficits.

Exosome and Macrophage Crosstalk in Sleep-Disordered Breathing-Induced Metabolic Dysfunction

Obstructive sleep apnea (OSA) is a highly prevalent worldwide public health problem that is characterized by repetitive upper airway collapse leading to intermittent hypoxia, pronounced negative intrathoracic pressures, and recurrent arousals resulting in sleep fragmentation. Obesity is a major risk factor of OSA and both of these two closely intertwined conditions result in increased sympathetic activity, oxidative stress, and chronic low-grade inflammation, which ultimately contribute, among other morbidities, to metabolic dysfunction, as reflected by visceral white adipose tissue (VWAT) insulin resistance (IR). Circulating extracellular vesicles (EVs), including exosomes, are released by most cell types and their cargos vary greatly and reflect underlying changes in cellular homeostasis. Thus, exosomes can provide insights into how cells and systems cope with physiological perturbations by virtue of the identity and abundance of miRNAs, mRNAs, proteins, and lipids that are packaged in the EVs cargo, and are secreted from the cells into bodily fluids under normal as well as diseased states. Accordingly, exosomes represent a novel pathway via which a cohort of biomolecules can travel long distances and result in the modulation of gene expression in selected and targeted recipient cells. For example, exosomes secreted from macrophages play a critical role in innate immunity and also initiate the adaptive immune response within specific metabolic tissues such as VWAT. Under normal conditions, phagocyte-derived exosomes represent a large portion of circulating EVs in blood, and carry a protective signature against IR that is altered when secreting cells are exposed to altered physiological conditions such as those elicited by OSA, leading to emergence of IR within VWAT compartment. Consequently, increased understanding of exosome biogenesis and biology should lead to development of new diagnostic biomarker assays and personalized therapeutic approaches. Here, the evidence on the major biological functions of macrophages and exosomes as pathophysiological effectors of OSA-induced metabolic dysfunction is discussed.

Circulating autoantibodies against neuroblastoma suppressor of tumorigenicity 1 (NBL1): A potential biomarker for coronary artery disease in patients with obstructive sleep apnea

Objective

Although severe obstructive sleep apnea (OSA) is an important risk factor for atherosclerosis-related diseases including coronary artery disease (CAD), there is no reliable biomarker of CAD risks in patients with OSA. This study aimed to test our hypothesis that circulating autoantibodies against neuroblastoma suppressor of tumorigenicity 1 (NBL1-Abs) are associated with the prevalence of CAD in patients with OSA.

Methods

Eighty-two adults diagnosed with OSA by polysomnography, 96 patients with a diagnosis of acute coronary syndrome (ACS) and 64 healthy volunteers (HVs) were consecutively enrolled. Serum samples were collected from patients with OSA at diagnostic polysomnography and from patients with ACS at disease onset. Serum NBL1-Ab level was measured by amplified luminescence proximity homogeneous assay and its association with clinical variables related to atherosclerosis was evaluated.

Results

NBL1-Ab level was significantly elevated in patients with both OSA and ACS compared with HVs. Subgroup analyses showed that NBL1-Ab level was markedly higher in patients with severe OSA and OSA patients with a history of CAD. Weak associations were observed between NBL1-Ab level and apnea-hypopnea index, age, mean SpO₂ and arousal index, whereas significantly higher NBL1-Ab levels were observed in OSA patients with a history of CAD than in those without a history of CAD. Sensitivity analysis using a logistic regression model also demonstrated that increased NBL1-Ab levels were associated with the previous history of CAD in patients with OSA.

Conclusions

Elevated NBL1-Ab levels may be associated with the prevalence of CAD in patients with OSA, which needs to be confirmed further.

Could omega-3 fatty acids a therapeutic treatment of the immune-metabolic consequence of intermittent hypoxia in obstructive sleep apnea?

Obesity and Obstructive sleep Apnea (OSA) seems to bi-directional; obesity itself increases the risk of OSA, but on the other hand, OSA may also predispose the individuals to weight gain, both obesity and OSA share a common immune-metabolic link state which have a synergistic effect on the activation of inflammation, insulin resistance and dyslipidemia, and cardiovascular disease. The Immune-metabolic role of omega-3 fatty acids Docosahexaenoic acid (DHA) and Eicosapentaenoic acid (EPA), which capable of modulating both metabolic and immune process, which may decrease pro-inflammatory cytokines, insulin resistance, and dyslipidemia. To date, no study in humans suffering from OSA and omega-3 fatty acids has been performed. Hence, the objective of this review aimed to discussing the link between immune-metabolic consequences related to intermittent hypoxia and does Omega-3 fatty acids a therapeutic treatment for co-morbidity associated with obstructive sleep apnea.

Inflammation mediates the association between visceral adiposity and obstructive sleep apnea in adolescents

Only a handful of studies, primarily in clinical samples, have reported an association between obesity, inflammation, and obstructive sleep apnea (OSA) in children and adolescents. No studies, however, have examined the pathogenetic link between visceral adiposity, systemic inflammation, and incident OSA in a large general population sample using objective measures of sleep and body fat. Adolescents (n = 392; mean age 17.0 ± 2.2 yr, 54.0% male) from the Penn State Child Cohort (PSCC) underwent 9-h overnight polysomnography; a DXA scan to assess body fat distribution; and a single fasting blood draw for the assessment of plasma interleukin-6 (IL-6), IL-6 soluble receptor (IL-6 sR), tumor necrosis factor alpha (TNFα), tumor necrosis factor receptor 1A (TNFR1), C-reactive protein (CRP), leptin, and adiponectin levels via ELISA. Visceral fat area was significantly elevated in moderate OSA (AHI ≥ 5), especially in boys. IL-6, CRP, and leptin were highest in adolescents with moderate OSA, even after adjusting for BMI percentile. Mediation analysis revealed that 42% of the association between visceral fat and OSA in adolescents was mediated by IL-6 (p = 0.03), while 82% of the association was mediated by CRP (p = 0.01). These data are consistent with the model of a feed-forward, vicious cycle, in which the release of proinflammatory cytokines by visceral adipocytes largely explains the association between central obesity and OSA; in turn, inflammation is also elevated in OSA independent of BMI. These findings, in a large, representative, non-clinical sample of young people, add to our understanding of the developmental pathogenesis of sleep apnea.

Chronic intermittent hypoxia exposure-induced atherosclerosis: a brief review

Obstructive sleep apnea (OSA) is highly prevalent in the USA and is recognized as an independent risk factor for atherosclerotic cardiovascular disease. Identification of atherosclerosis risk factor attributable to OSA may provide opportunity to develop preventive measures for cardiovascular risk reduction. Chronic intermittent hypoxia (CIH) is a prominent feature of OSA pathophysiology and may be a major mechanism linking OSA to arteriosclerosis. Animal studies demonstrated that CIH exposure facilitated high-cholesterol diet (HCD)-induced atherosclerosis, accelerated the progression of existing atherosclerosis, and induced atherosclerotic lesions in the absence of other atherosclerosis risk factors, demonstrating that CIH is an independent causal factor of atherosclerosis. Comparative studies revealed major differences between CIH-induced and the classic HCD-induced atherosclerosis. Systemically, CIH was a much weaker inducer of atherosclerosis. CIH and HCD differentially activated inflammatory pathways. Histologically, CIH-induced atherosclerotic plaques had no clear necrotic core, contained a large number of CD31+ endothelial cells, and had mainly elastin deposition, whereas HCD-induced plaques had typical necrotic cores and fibrous caps, contained few endothelial cells, and had mainly collagen deposition. Metabolically, CIH caused mild, but HCD caused more severe dyslipidemia. Mechanistically, CIH did not, but HCD did, cause macrophage foam cell formation. NF-κB p50 gene deletion augmented CIH-induced, but not HCD-induced atherosclerosis. These differences reflect the intrinsic differences between the two types of atherosclerosis in terms of pathological nature and underlying mechanisms and support the notion that CIH-induced atherosclerosis is a new paradigm that differs from the classic HCD-induced atherosclerosis.

[Effects of different surgical procedures on immunity of children with obstructive sleep apnea hypopnea syndrome]

OBJECTIVE

To explore the effects of pure adenoidectomy,adenoidectomy with partial tonsillectomy,and adenoidectomy with total tonsillectomy on humoral and cellular immunity of children with OSAHS.

METHOD

The children with OSAHS diagnosed by polysomnography were divided into pure adenoidectomy group(group A),adenoidectomy with partial tonsillectomy group(group B), and adenoidectomy with total tonsillectomy(group C), and there were 50 cases in each group. The serum IgG, IgA, IgM level and peripheral blood T cell subgroup per-centage were detected at 6 months preoperatively and postoperatively. Tonsil grading and polysomnography wereconducted, recording symptoms improvement situation at postoperative 6 months.

RESULT

There was no statisticallysignificant difference compared with preoperative(P>0. 05) in humoral immunity and cellular immunity index ofpostoperative 6 months. There was no significani difference(P>C. 05) in curative effect among three groups in the 6th month post-operatively.

CONCLUSION

All of these three surgical procedures had no obvious effect on humoral orcellular immune function in children, and could effectively treat children OSAHS.

Polyclonal, newly derived T cells with low expression of inhibitory molecule PD-1 in tonsils define the phenotype of lymphocytes in children with Periodic Fever, Aphtous Stomatitis, Pharyngitis and Adenitis (PFAPA) syndrome

PURPOSE

PFAPA syndrome is a benign, recurrent inflammatory disease of childhood. Tonsillectomy is one of the therapeutic options with a yet unexplained biological mechanism. We tested whether specific lymphocyte subsets recruited from blood to human tonsils participate in PFAPA pathogenesis.

METHODS

Paired tonsils/peripheral blood (PB) samples were investigated (a) from children with PFAPA that successfully resolved after tonsillectomy (n=10) (b) from children with obstructive sleep apnoea syndrome as controls (n=10). The lymphocyte profiles were analysed using 8-colour flow cytometry, immunoglobulin (IGH) and T-cell receptor (TCR) gene rearrangements via PCR and next generation sequencing; a TREC/KREC analysis was performed using qPCR.

RESULTS

The PFAPA tonsils in the asymptomatic phase had a lower percentage of B-lymphocytes than controls; T-lymphocyte counts were significantly higher in PB. The percentages of cytotoxic CD8pos T-lymphocytes were approximately 2-fold higher in PFAPA tonsils; the transitional B cells and naïve stages of both the CD4pos and CD8pos T-lymphocytes with a low expression of PD-1 molecule and high numbers of TREC were also increased. With the exception of elevated plasmablasts, no other differences were significant in PB. The expression levels of CXCL10, CXCL9 and CCL19 genes were significantly higher in PFAPA tonsils. The IGH/TCR pattern showed no clonal/oligoclonal expansion. DNA from the Epstein-Barr virus, Human Herpervirus-6 or adenovirus was detected in 7 of 10 PFAPA tonsils but also in 7 of 9 controls.

CONCLUSIONS

Our findings suggest that the uninhibited, polyclonal response of newly derived lymphocytes participate in the pathogenesis of PFAPA. Because most of the observed changes were restricted to tonsils and were not present in PB, they partly explain the therapeutic success of tonsillectomy in PFAPA syndrome.

Chapter 8 Military Personnel With Traumatic Brain Injuries and Insomnia Have Reductions in PTSD and Improved Perceived Health Following Sleep Restoration: A Relationship Moderated by Inflammation

BACKGROUND

Up to one-third of deployed military personnel sustain a traumatic brain injury (TBI). TBIs and the stress of deployment contribute to the vulnerability for chronic sleep disturbance, resulting in high rates of insomnia diagnoses as well as symptoms of posttraumatic stress disorder (PTSD), depression, and declines in health-related quality of life (HRQOL). Inflammation is associated with insomnia; however, the impact of sleep changes on comorbid symptoms and inflammation in this population is unknown.

METHODS

In this study, we examined the relationship between reported sleep changes and the provision of the standard of care, which could include one or more of the following: cognitive behavioral therapy (CBT), medications, and continuous positive airway pressure (CPAP). We compared the following: (a) the group with a decrease in the Pittsburgh Sleep Quality Index (PSQI; restorative sleep) and (b) the group with no change or increase in PSQI (no change). Independent t tests and chi-square tests were used to compare the groups on demographic and clinical characteristics, and mixed between-within subjects analysis of variance tests were used to determine the effect of group differences on changes in comorbid symptoms. Linear regression models were used to examine the role of inflammation in changes in symptoms and HRQOL.

RESULTS

The sample included 70 recently deployed military personnel with TBI, seeking care for sleep disturbances. Thirty-seven participants reported restorative sleep and 33 reported no sleep changes or worse sleep. The two groups did not differ in demographic characteristics or clinical symptoms at baseline. The TBI+restored sleep group had significant reductions in PTSD and depression over the 3-month period, whereas the TBI+no change group had a slight increase in both PTSD and depression. The TBI+restored sleep group also had significant changes in HRQOL, including the following HRQOL subcomponents: physical functioning, role limitations in physical health, social functioning, emotional well-being, energy/fatigue, and general health perceptions. In a linear regression model using a forced entry method, the dependent variable of change in C-reactive protein (CRP) concentrations was significantly related to changes in PTSD symptoms and HRQOL in the TBI+restored sleep group, with R2=0.43, F33,3=8.31, p<.01.

CONCLUSIONS

Military personnel with TBIs who have a reduction in insomnia symptoms following a standard-of-care treatment report less severe symptoms of depression and PTSD and improved HRQOL, which relate to decreased plasma concentrations of CRP. These findings suggest that treatment for sleep disturbances in this TBI+military population is associated with improvements in health and decreases in inflammation. The contributions of inflammation-induced changes in PTSD and depression in sleep disturbances in TBI + military personnel require further study.

The linkage of allergic rhinitis and obstructive sleep apnea

Rhinitis can be divided into allergic and non-allergic rhinitis. Rhinitis, particularly allergic rhinitis, has been shown to be associated with obstructive sleep apnea; a condition characterized by repetitive upper airway obstruction during sleep. Allergic rhinitis increases the risk of developing obstructive sleep apnea by two major mechanisms: 1) increase in airway resistance due to higher nasal resistance and 2) reduction in pharyngeal diameter from mouth breathing that moves the mandible inferiorly. Other inflammatory mediators including histamine, CysLTs, IL 1β and IL-4 found in high levels in allergic rhinitis, have also been shown to worsen sleep quality in obstructive sleep apnea. Prior studies have shown that treatment of allergic rhinitis, particularly when intranasal steroid are used, improved obstructive sleep apnea. Leukotriene receptor antagonists were also associated with positive results on obstructive sleep apnea in adult patients with concomitant allergic rhinitis but current data are limited in the case of children.

Impairment of high-density lipoprotein resistance to lipid peroxidation and adipose tissue inflammation in obesity complicated by obstructive sleep apnea

CONTEXT

Obstructive sleep apnea (OSA) complicates morbid obesity and is associated with increased cardiovascular disease incidence. An increase in the circulating markers of chronic inflammation and dysfunctional high-density lipoprotein (HDL) occur in severe obesity.

OBJECTIVE

The objective of the study was to establish whether the effects of obesity on inflammation and HDL dysfunction are more marked when complicated by OSA.

DESIGN AND PATIENTS

Morbidly obese patients (n = 41) were divided into those whose apnea-hypoapnea index (AHI) was more or less than the median value and on the presence of OSA [OSA and no OSA (nOSA) groups]. We studied the antioxidant function of HDL and measured serum paraoxonase 1 (PON1) activity, TNFα, and intercellular adhesion molecule 1 (ICAM-1) levels in these patients. In a subset of 19 patients, we immunostained gluteal sc adipose tissue (SAT) for TNFα, macrophages, and measured adipocyte size.

RESULTS

HDL lipid peroxide levels were higher and serum PON1 activity was lower in the high AHI group vs the low AHI group (P < .05 and P < .0001, respectively) and in the OSA group vs the nOSA group (P = .005 and P < .05, respectively). Serum TNFα and ICAM-1 levels and TNFα immunostaining in SAT increased with the severity of OSA. Serum PON1 activity was inversely correlated with AHI (r = -0.41, P < .03) in the OSA group. TNFα expression in SAT directly correlated with AHI (r = 0.53, P < .03) in the subset of 19 patients from whom a biopsy was obtained.

CONCLUSION

Increased serum TNFα, ICAM-1, and TNFα expression in SAT provide a mechanistic basis for enhanced inflammation in patients with OSA. Decreased serum PON1 activity, impaired HDL antioxidant function, and increased adipose tissue inflammation in these patients could be a mechanism for HDL and endothelial dysfunction.

What non-alcoholic fatty liver disease has got to do with obstructive sleep apnoea syndrome and viceversa?

Non-alcoholic fatty liver disease (NAFLD) and obstructive sleep apnoea syndrome (OSAS) are common conditions, frequently encountered in patients with obesity and/or metabolic syndrome. NAFLD and OSAS are complex diseases that involve an interaction of several intertwined factors. Several lines of evidence lend credence to an immune system derangement in these patients, i.e. the low grade chronic inflammation status, reckoned to be the most important factor in causing and maintaining these two illnesses. Furthermore, it is emphasized the main role of spleen involvement, as a novel mechanism. In this review the contribution of the visceral adiposity in both NAFLD and OSAS is stressed as well as the role of intermittent hypoxia. Finally, a post on the prevention of systemic inflammation is made.

What non-alcoholic fatty liver disease has got to do with obstructive sleep apnoea syndrome and viceversa?

Non-alcoholic fatty liver disease (NAFLD) and obstructive sleep apnoea syndrome (OSAS) are common conditions, frequently encountered in patients with obesity and/or metabolic syndrome. NAFLD and OSAS are complex diseases that involve an interaction of several intertwined factors. Several lines of evidence lend credence to an immune system derangement in these patients, i.e. the low grade chronic inflammation status, reckoned to be the most important factor in causing and maintaining these two illnesses. Furthermore, it is emphasized the main role of spleen involvement, as a novel mechanism. In this review the contribution of the visceral adiposity in both NAFLD and OSAS is stressed as well as the role of intermittent hypoxia. Finally, a post on the prevention of systemic inflammation is made.

A novel non-rapid-eye movement and rapid-eye-movement parasomnia with sleep breathing disorder associated with antibodies to IgLON5: a case series, characterisation of the antigen, and post-mortem study

BACKGROUND

Autoimmunity might be associated with or implicated in sleep and neurodegenerative disorders. We aimed to describe the features of a novel neurological syndrome associated with prominent sleep dysfunction and antibodies to a neuronal antigen.

METHODS

In this observational study, we used clinical and video polysomnography to identify a novel sleep disorder in three patients referred to the Sleep Unit of Hospital Clinic, University of Barcelona, Spain, for abnormal sleep behaviours and obstructive sleep apnoea. These patients had antibodies against a neuronal surface antigen, which were also present in five additional patients referred to our laboratory for antibody studies. These five patients had been assessed with polysomnography, which was done in our sleep unit in one patient and the recording reviewed in a second patient. Two patients underwent post-mortem brain examination. Immunoprecipitation and mass spectrometry were used to characterise the antigen and develop an assay for antibody testing. Serum or CSF from 298 patients with neurodegenerative, sleep, or autoimmune disorders served as control samples.

FINDINGS

All eight patients (five women; median age at disease onset 59 years [range 52-76]) had abnormal sleep movements and behaviours and obstructive sleep apnoea, as confirmed by polysomnography. Six patients had chronic progression with a median duration from symptom onset to death or last visit of 5 years (range 2-12); in four the sleep disorder was the initial and most prominent feature, and in two it was preceded by gait instability followed by dysarthria, dysphagia, ataxia, or chorea. Two patients had a rapid progression with disequilibrium, dysarthria, dysphagia, and central hypoventilation, and died 2 months and 6 months, respectively, after symptom onset. In five of five patients, video polysomnography showed features of obstructive sleep apnoea, stridor, and abnormal sleep architecture (undifferentiated non-rapid-eye-movement [non-REM] sleep or poorly structured stage N2, simple movements and finalistic behaviours, normalisation of non-REM sleep by the end of the night, and, in the four patients with REM sleep recorded, REM sleep behaviour disorder). Four of four patients had HLA-DRB1*1001 and HLA-DQB1*0501 alleles. All patients had antibodies (mainly IgG4) against IgLON5, a neuronal cell adhesion molecule. Only one of the 298 controls, who had progressive supranuclear palsy, had IgLON5 antibodies. Neuropathology showed neuronal loss and extensive deposits of hyperphosphorylated tau mainly involving the tegmentum of the brainstem and hypothalamus in the two patients studied.

INTERPRETATION

IgLON5 antibodies identify a unique non-REM and REM parasomnia with sleep breathing dysfunction and pathological features suggesting a tauopathy.

FUNDING

Fondo de Investigaciones Sanitarias, Centros de Investigación Biomédica en Red de enfermedades neurodegenerativas (CIBERNED) and Respiratorias (CIBERES), Ministerio de Economía y Competitividad, Fundació la Marató TV3, and the National Institutes of Health.

Intermittent hypoxia-induced changes in tumor-associated macrophages and tumor malignancy in a mouse model of sleep apnea

RATIONALE

An increased cancer aggressiveness and mortality have been recently reported among patients with obstructive sleep apnea (OSA). Intermittent hypoxia (IH), a hallmark of OSA, enhances melanoma growth and metastasis in mice.

OBJECTIVES

To assess whether OSA-related adverse cancer outcomes occur via IH-induced changes in host immune responses, namely tumor-associated macrophages (TAMs).

MEASUREMENTS AND MAIN RESULTS

Lung epithelial TC1 cell tumors were 84% greater in mice subjected to IH for 28 days compared with room air (RA). In addition, TAMs in IH-exposed tumors exhibited reductions in M1 polarity with a shift toward M2 protumoral phenotype. Although TAMs from tumors harvested from RA-exposed mice increased TC1 migration and extravasation, TAMs from IH-exposed mice markedly enhanced such effects and also promoted proliferative rates and invasiveness of TC1 cells. Proliferative rates of melanoma (B16F10) and TC1 cells exposed to IH either in single culture or in coculture with macrophages (RAW 264.7) increased only when RAW 264.7 macrophages were concurrently present.

CONCLUSIONS

Our findings support the notion that IH-induced alterations in TAMs participate in the adverse cancer outcomes reported in OSA.

[Tonsillectomy and adenoidectomy in children with obstructive sleep apnea hypopnea syndrome postoperative immune function influence]

Sleep apnea hypopnea syndrome is a common respiratory tract obstructive disease in children, which often affects children's mental and physical development. For repeated tonsil inflammation and nocturnal sleep apnea in children with OSAHS, tonsillectomy and adenoidectomy is the most effective treatment. But children's postoperative immune function remain in dispute, this review focuses on immunologic function change and influence in the OSAHS children after tonsillectomy and adenoidectomy, according to the existing research results can be confirmed. The immune parameters in OSAHS children who had tonsillectomy and adenoidectomy will vary differently after a short period of several, considering these manifestations are the stress response after operation, and its long-term immune parameters can recover to the normal level. Thus, the postoperative immune function of OSAHS with tonsillitis in children after the adenoid and tonsil resection has no negative effects, providing theory basis for clinician's treatment for clinicians to parents of children with answers to questions provide the theory basis.

[Postoperative changes of immunity in children undergoing adenoidectomy with tonsil ablation or with partial tonsillectomy]

OBJECTIVE

To investigate the changes of humoral and cellular immune responses in children with OSAHS after adenoidectomy with tonsil ablation or partial tonsillectomy by a plasma-mediated radiofrequency-based device.

METHOD

Seventy children with OSAHS were enrolled in the study. According to the size of tonsils, they were divided into two groups: the adenoidectomy with tonsil ablation group and the adenoidectomy with partial tonsillectomy group. 4 ml of peripheral venous blood was drawn before and 1 month, 3 months after operation. Serum IgG, IgA, IgM levels and peripheral blood T lymphocyte subsets were measured.

RESULT

In the adenoidectomy with tonsil ablation group, the level of CD3+ and CD4+ /CD8+ ration were slightly increased, while the levels of CD4+ and CD8+ were slightly reduced at 1 month after operation as compared to preoperative period. However, in the adenoidectomy with partial tonsillectomy group, the levels of CD8+ at 1 month after operation were slightly increased compared with that in preoperative examination, while the CD3+, CD4+ level and the CD4+/CD8+ ratio were slightly reduced during the same period. In addition, the levels of serum immunoglobulins showed no significant difference between the two groups, and returned to the preoperative levels at 3 months after operation in both groups (P > 0.05).

CONCLUSION

The results of the present study indicate that the humoral and cellular immunity is not affected in children with OSAHS who undergo adenoidectomy with tonsil ablation or partial tonsillectomy using plasma-mediated radiofrequency ablation. The patients' immune functions can return to normal levels at 3 months after the surgery.

Anti-inflammatory therapy for obstructive sleep apnea in children

QUESTION

A 4-year-old child was diagnosed by polysomnography as experiencing mild obstructive sleep apnea (OSA). Despite the child being inattentive and distracted during the day at school, his parents prefer to avoid surgical treatment (adenotonsillectomy). Are there any non-surgical treatments for mild OSA in young children?

ANSWER

Obstructive sleep apnea in children is caused mainly by adenotonsillar hypertrophy and can lead to considerable morbidities, including neurocognitive and behavioural disturbances. Surgical removal of the tonsils and adenoids is the treatment of choice. In recent years, however, a new understanding of the inflammatory components of OSA has led to the assumption that anti-inflammatory treatment can reduce adenotonsillar size and improve OSA symptoms. Evidence from a few studies suggests that intranasal steroids and oral leukotriene receptor antagonists have beneficial effects, but data from randomized controlled trials are still lacking.

[Immune function changes in patients with obstructive sleep apnea hypopnea syndrome]

OBJECTIVE

To explore the potential changes in the immune function of patients with obstructive sleep apnea hypopnea syndrome (OSAHS).

METHODS

We carried out a retrospective cross-sectional study of 187 patients with established OSAHS and 20 healthy subjects (control). For all the patients, the medical history was carefully examined, and overnight sleep monitoring was carried out with detection of the humoral and cellular immunity.

RESULTS

We found a significant increase in the levels of C3 and a decrease in both the IgM level and NK cell percentage in OSAHS patients as compared to the control group (P<0.01). Correlation analysis indicated that C3 was positive correlated to AHI but inversely to the lowest pulse oxygen saturation (LSpO(2)); IgM showed a mild positively correlation to LSpO(2), and NK cells had a mild inverse correlation to AHI. The other immunological indices were not found to undergo noticeable changes or show correlations in OSAHS.

CONCLUSION

Immune function changes occur in patients with OSAHS, characterized primarily by deteriorations in the humoral and cellular immunity.

Increased cellular proliferation and inflammatory cytokines in tonsils derived from children with obstructive sleep apnea

Adenotonsillar hypertrophy is the major pathophysiological mechanism underlying obstructive sleep apnea (OSA) and recurrent tonsillitis (RI) in children. The increased expression of various mediators of the inflammatory response in tonsils of patients with OSA prompted our hypothesis that the enhanced local and systemic inflammation in children with OSA would promote tonsillar proliferation. Mixed cell cultures from tonsils recovered during adenotonsillectomy in children with OSA and RI were established, and proliferative rates were assessed. Cells were also cultured to determine the levels of proinflammatory cytokines and antioxidant protein levels and mRNA expression. Global cell proliferative rates from OSA tonsils were significantly higher than RI (p < 0.01), with CD3, CD4, and CD8 cell proliferation being higher in OSA (p < 0.05). Moreover, proinflammatory cytokines, such as TNF-alpha, IL-6, and IL-1alpha, were highly expressed in OSA-derived tonsils. Furthermore, thioredoxin (TRX), an antioxidant protein, was also highly expressed in OSA tonsils at the mRNA and protein levels (p < 0.01). Thus, T cells are in a highly proliferative state in the tonsils of children with OSA and are associated with increased production of proinflammatory cytokines and TRX, when compared with children with RI.

Sleep duration and biomarkers of inflammation

INTRODUCTION

Extremes of sleep duration have been associated with adverse health outcomes. The mechanism is unclear but may be related to increased inflammation. We sought to assess the association between sleep duration and inflammatory biomarkers.

METHODS

A total of 614 individuals from the Cleveland Family Study completed questionnaires about sleep habits and underwent polysomnography. A morning fasting blood sample was assayed for 5 inflammatory cytokines.

RESULTS

In this cohort, mean (SD) habitual sleep duration based on self-report was 7.6 (1.6) h and mean sleep duration by polysomnography (PSG) on the night prior to blood sampling was 6.2 (1.3) h. After adjusting for obesity and apnea severity, each additional hour of habitual sleep duration was associated with an 8% increase in C-reactive protein (CRP) levels (P=0.004) and 7% increase in interleukin-6 (IL-6) levels (P=0.0003). These associations were independent of self-reported sleepiness. In contrast, PSG sleep duration was inversely associated with tumor necrosis factor alpha (TNFa) levels. For each hour reduction in sleep, TNFalpha levels increased by 8% on average (P=0.02). Sleep duration was not associated with IL-1 or IL-10.

CONCLUSIONS

Increases in habitual sleep durations are associated with elevations in CRP and IL-6 while reduced PSG sleep duration is associated with elevated TNFa levels. Activation of pro-inflammatory pathways may represent a mechanism by which extreme sleep habits affect health.

[Alteration of the immune function in children with obstruction sleep apnea hypopnea syndrome]

OBJECTIVE

To study the alteration of the immune function in children with obstructive sleep apnea hypopnea syndrome.

METHOD

The changes of the IgG, IgA, IgM, CD3, CD4 and CD8 levels in serum were observed and analyzed pre and post adenoidectomy and tonsillectomy.

RESULT

Post-operatively, the level of IgG, IgA, IgM, and the CD3, CD4 and CD8 in serum showed no evident alteration.

CONCLUSION

Adenoidectomy and tonsillectomy have no injury on the immune function of children with OSAHS.

[Peri-uvulopalatopharyngoplasty erythrocyte immune function analysis in patients with obstructive sleep apnea hypopnea syndrome]

OBJECTIVE

To investigate the effect of ECR I, RBC-C3bRR, RBC-ICR on obstructive sleep apnea-hypopnea syndrome (OSAHS).

METHOD

Fifty-four inpatients with OSAHS and 20 healthy controls at the same age were enrolled. 1 ml fresh whole blood with stomach empty in early morning were collected before and after the surgery to detect ECR I , RBC-C3bRR and RBC-ICR.

RESULT

The erythrocyte immune function of the OSAHS group was lower than that of the control group.

CONCLUSION

Erythrocyte immune functional disorder plays an important role in OSAHS and surgical procedures is effective in correcting the changes.

Systemic inflammation in non-obese children with obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) has been associated with increased systemic inflammatory responses that may contribute to an increased risk for end-organ morbidity. The changes in levels of pro-inflammatory cytokine IL-6 , and the anti-inflammatory cytokine IL-10, both of which play a major role in atherogenesis, a major consequence of OSA, have not specifically been assessed in pediatric patients.

METHODS

Consecutive non-obese children (aged 4-9years) who were polysomnographically diagnosed with OSA, and age-, gender-, ethnicity-, and BMI-matched control children underwent a blood draw the next morning after a sleep study and plasma samples were assayed for interleukins 6 (IL-6) and 10 (IL-10). These tests were repeated 4-6months after tonsillectomy and adenoidectomy (T&A) in children with OSA.

RESULTS

IL-6 levels were higher and IL-10 plasma levels were lower in children with OSA and returned to control levels after T&A.

CONCLUSIONS

Systemic inflammation is a constitutive component and consequence of OSA in many children, even in the absence of obesity, and is reversible upon treatment in most patients.

Inflammatory proteins in patients with obstructive sleep apnea with and without daytime sleepiness

Excessive daytime sleepiness (EDS) is one of the most frequent symptoms in patients with obstructive sleep apnea syndrome (OSAS). However, not all patients with OSAS manifest EDS. The aim of this study was to assess whether differential circulatory levels of inflammatory mediators would account for differences in somnolence among patients with OSAS. Patients were prospectively recruited from referral patient cohort to the university hospital sleep center. A total of 50 consecutive patients with OSAS undergoing overnight polysomnography with or without EDS and 20 controls were evaluated. EDS was assessed using the Epworth sleepiness scale (ESS) and the multiple sleep latency test after overnight polysomnography. EDS was defined when the ESS was >10 and the mean sleep latency <10 min. Fasting blood was drawn in the morning after polysomnography. Circulating levels of tumor necrosis factor alpha (TNFalpha), interleukin-6 (IL-6), intercellular adhesion molecule 1 (ICAM-1), 8-isoprostaglandin F2alpha (8-iso-PGF2alpha), and P-selectin were measured with commercially available high sensitivity kits. Although patients with OSAS have elevated levels of ICAM-1, IL-6, and TNFalpha, there were no statistically significant differences in any of the inflammatory mediators between patients with EDS and without EDS. Emergence of EDS in the context of OSA does not appear to result from the selective increase of any particular somnogenic substance, i.e., TNFalpha, IL-6, ICAM-1, 8-iso-PGF2alpha, and P-selectin in the context of sleep-disordered breathing.

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.

C-reactive protein is associated with sleep disordered breathing independent of adiposity

STUDY OBJECTIVES

It is well established that medical conditions such as obesity and cardiovascular disease are associated with increased levels of inflammatory biomarkers such as C-reactive protein (CRP). Prior studies have produced inconsistent results regarding the association between sleep disordered breathing (SDB) and CRP, possibly due to the confounding effects of obesity or medical comorbidity. The present study examined the association between degree of SDB and level of CRP independent of prevalent medical conditions and obesity.

DESIGN

Cross-sectional study.

SUBJECTS AND SETTING

University-based clinical sample referred for diagnostic polysomnography.

MEASUREMENTS AND RESULTS

The study sample consisted of 69 men (mean age 40 years; mean BMI of 31.2 kg/m2) free of prevalent medical conditions including hypertension, diabetes mellitus, and cardiovascular disease. Measurements of morning and evening CRP levels were performed along with full-montage polysomnography. Confounding due to obesity was assessed by adjustments for body mass index, waist circumference, and percent body fat. A strong association was found between degree of SDB and serum levels of CRP, with or without adjustment for age and several measures of adiposity. Between the lowest and highest quartiles of apnea-hypopnea index (AHI) the mean difference in adjusted level of CRP was 3.88 microg/ml (P < 0.001). Moreover, an independent association between serum CRP levels and nocturnal hypoxia was also observed, whereas no association was noted with parameters of sleep architecture.

CONCLUSIONS

While more research is needed to elucidate causal pathways involving the effects of sleep-related hypoxia on low-grade systemic inflammation, the results of this study suggest that mechanisms other than adiposity per se could contribute to the inflammatory state seen in adults with SDB.

Hypoxemia and obesity modulate plasma C-reactive protein and interleukin-6 levels in sleep-disordered breathing

C-reactive protein (CRP) and interleukin-6 (IL-6) are pro-inflammatory proteins and important risk factors for atherosclerosis. Plasma CRP levels in snoring children may or may not be elevated. Since obesity is prevalent among snoring children and is associated with elevated CRP levels, we aimed to investigate the relative contributions of sleep-disordered breathing (SDB) and obesity to the inflammatory processes in snoring children in this prospective study. Two hundred forty-four children (mean age 8.9 +/- 3.4 years) underwent polysomnographic evaluation. CRP was measured the following morning, and plasma IL-6 levels from 111 randomly selected children were also examined. Plasma CRP and IL-6 levels were elevated in children with SDB. Log plasma CRP levels were higher in the moderate-severe SDB group (apnea/hypopnea index, AHI > or = 5) compared to the mild SDB group (AHI > or = 1 and <5; p < 0.0001) or the control group (AHI < 1; p = 0.0001). Log plasma CRP levels correlated with AHI, arousal index, relative BMI, and SpO(2) nadir (r = 0.30, p < 0.0001; r = 0.21, p = 0.002; r = 0.39, p < 0.0001, r = -0.36, p < 0.0001, respectively). Log plasma CRP levels were lower in children with SpO(2) nadir > or =90 (p < 0.0001). Sub-analysis of the 116 non-obese children in the cohort revealed similar findings. Log plasma IL-6 levels were increased in children with moderate-severe SDB compared to controls (p = 0.03) and correlated with AHI (r = 0.28, p = 0.003) and SpO(2) nadir (r = -0.24, p = 0.02). Children with SDB display significant severity-dependent increases in plasma CRP and IL-6 levels independent of obesity.

Lymphocyte activation as a possible measure of atherosclerotic risk in patients with sleep apnea

Obstructive sleep apnea (OSA), a breathing disorder in sleep characterized by intermittent hypoxia and sleep fragmentation, constitutes an independent risk factor for cardiovascular morbidity. Investigating how this breathing disorder modulates immune responses may facilitate understanding one of the risk factors for atherosclerosis. T cells play a significant role in atherogenesis and plaque development via cytokine production and by directly contributing to vascular injury. Using flow cytometry and chromium release assays, we found that CD4 and CD8 T cells of OSA patients undergo phenotypic and functional changes and acquire cytotoxic capabilities. Thus, a shift in CD4 and CD8 T cells toward type 2 cytokine dominance with increased IL-4 expression was noted. IL-10 expression in T cells was negatively correlated with the severity of OSA, as determined by the apnea-hypopnea index (AHI), whereas TNF-alpha was positively correlated. CD8 T cells of OSA patients expressed a fourfold increase in TNF-alpha and CD40 ligand (CD40L), and exhibited an increased OSA severity-dependent cytotoxicity against endothelial cells. The percentage of CD4(+)CD28(null) and cytotoxicity of CD4 T lymphocytes were also significantly higher in OSA patients than in controls. Nasal continuous positive airway pressure (nCPAP) treatment, which ameliorated the severity of OSA, significantly lowered TNF-alpha and CD40L expression, and decreased cytotoxicity in CD8 T cells. In conclusion, increased cytotoxicity and cytokine imbalance in CD4 and CD8 T cells may be involved in atherogenesis in OSA. Nasal CPAP treatment ameliorates some lymphocyte dysfunctions and thus may moderate some atherogenic pathways.

Increased carotid intima-media thickness and serum inflammatory markers in obstructive sleep apnea

Increased carotid intima-media thickness (IMT) and increased serum levels of inflammatory markers, such as C-reactive protein (CRP), interleukin (IL)-6, and IL-18, are associated with an increased risk of cardiovascular and cerebrovascular diseases. The aim of this study was to evaluate whether carotid IMT, a useful marker for early atherosclerosis, is associated with these inflammatory markers in patients with obstructive sleep apnea (OSA). Carotid IMT was investigated with ultrasonography in 36 patients with OSA and 16 obese control subjects. Serum levels of CRP, IL-6, and IL-18 were measured at 5:00 A.M. Carotid IMT (p < 0.001) and serum levels of CRP (p < 0.003), IL-6 (p < 0.005), and IL-18 (p < 0.03) of patients with OSA were significantly higher than those of obese control subjects. Carotid IMT was significantly correlated with serum levels of CRP (r = 0.61, p = 0.0001), IL-6 (r = 0.41, p = 0.01), and IL-18 (r = 0.45, p = 0.005), duration of OSA-related hypoxia (r = 0.60, p = 0.0001), and severity of OSA (r = 0.50, p = 0.002). In addition, the primary factor influencing carotid IMT was duration of hypoxia during total sleep time (p = 0.036). These results suggest that OSA-related hypoxia and systemic inflammation might be associated with the progression of atherosclerosis and thus might increase the risks of cardiovascular and cerebrovascular morbidity in patients with OSA.

The relationship between serum cytokine levels with obesity and obstructive sleep apnea syndrome

Inflammatory cytokines such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) may have a direct effect on glucose and lipid metabolism. On the other hand, it is known that IL-6 and TNF-alpha are important pro-inflammatory cytokines in the pathogenesis of atherosclerosis. The goal of present study was to test whether sleep apnea contributes to the previously reported increases of IL-6 and TNF-alpha independent of obesity. Forty-three obese (body mass index, BMI>27 kg/m2) men with newly diagnosed obstructive sleep apnea syndrome (OSAS) (apnea-hypopnea index, AHI> or =5) and age- and BMI-matched 22 obese nonapneic male controls (AHI<5) were enrolled in this study. To confirm the diagnosis, all patients underwent standard polysomnography in the sleep disorders center. Serum samples were taken at 08:00 h in the morning after overnight fasting. Serum IL-6 and TNF-alpha levels were found significantly higher in OSAS patients than in controls (p=0.002, p=0.03). Serum IL-6 and TNF-alpha levels were significantly correlated with AHI in OSAS patients (r=0.03, p=0.046 and r=0.36, p=0.016). There was no significant correlation between serum IL-6, TNF-alpha levels and AHI in controls. Serum IL-6 and TNF-alpha levels were not correlated with BMI both in OSAS patients and controls. In conclusion, circulating IL-6 and TNF-alpha levels in patients with OSAS, as independent of BMI are significantly higher than levels in controls and there is a positive relationship between previously mentioned cytokines' levels and the severity of OSAS. According to these results, the link between cardiovascular morbidity and OSAS may be explained by the coexistence of other cardiovascular risk factors such as circulating IL-6 and TNF-alpha levels.

Nasal cytology: a marker of clinically silent inflammation in patients with obstructive sleep apnea and a predictor of noncompliance with nasal CPAP therapy

STUDY OBJECTIVES

Patients with obstructive sleep apnea treated with nasal continuous positive airway pressure (CPAP) often complain of nasal side effects. We studied patients before and after initiation of nasal CPAP to see how treatment affected nasal function and markers of nasal inflammation. We searched for pretreatment findings that might help to predict noncompliance.

METHODS

Nasal symptom scores, nasal flow by anterior rhinomanometry, mediator levels (intercellular adhesion molecule-1, interleukin-6, interleukin-8 and interleukin-13), and nasal scrapes for cytology were obtained at baseline and monthly for up to 3 months of nasal CPAP therapy. Compliance was assessed from the patient's report and by recording hours of usage for up to 19 months of follow-up.

RESULTS

Thirty-eight patients with newly diagnosed obstructive sleep apnea were classified as having no rhinitis (42%), allergic rhinitis (37%), or nonallergic rhinitis (21%). There was no significant difference in compliance in patients with and without rhinitis. Compliant and noncompliant patients showed no significant differences in their baseline nasal symptom scores, nasal flow, and mediator levels. Nasal neutrophil counts before treatment were greater in noncompliant than in compliant patients (p = .004) and greater in those discontinuing because of nasal symptoms than in patients who quit for other reasons (p = .05). There was a positive correlation between neutrophil counts and nasal bacterial scores, both before and after treatment with nasal CPAP.

CONCLUSIONS

Patients with increased neutrophil counts in the nasal scrape before beginning nasal CPAP are at increased risk of discontinuing therapy. They appear to have subclinical nasal inflammation that cannot be identified from clinical assessment, nasal symptom scores or rhinomanometry.

Activated CD8+ T-lymphocytes in obstructive sleep apnoea

T-lymphocytes are implicated in the development of atherosclerosis. The aim of this study was to assess whether the CD8+ T-lymphocytes of obstructive sleep apnoea (OSA) patients undergo phenotypic and functional changes that may exaggerate atherogenic sequelae in OSA. A total of 36 OSA patients, 17 controls and 15 single-night-treated OSA patients were studied. Phenotype and cytotoxicity against K562 target cells were analysed by flow cytometry. Cytotoxicity against human umbilical vein endothelial cells (HUVECs) was assessed by 51Cr release assay. The cytotoxicity of the CD8+ T-lymphocytes of OSA patients against K562 and HUVECs was significantly greater than controls. This increased cytotoxicity directly depended on the presence of perforin and natural killer receptors (CD56, CD16), which were significantly increased in OSA CD8+ T-lymphocytes. Also the percentage of the CD56bright subset, which mediates initial interactions with vascular endothelium, significantly increased in OSA. Nasal continuous positive airway pressure treatment significantly decreased CD8+ T-cell cytotoxicity and CD56 expression, and was positively correlated with natural killer inhibitory NKB1 receptor expression either after a single-night treatment or after a prolonged treatment. In conclusion, the CD8+ T-lymphocytes of obstructive sleep apnoea patients undergo phenotypic and functional changes, rendering them cytotoxic to target cells via increased CD56+/perforin+ expression, which can be ameliorated by nasal continuous positive airway pressure treatment. These results are compatible with the current authors' hypothesis of atherogenic sequelae in obstructive sleep apnoea.

Resistin levels in patients with obstructive sleep apnoea syndrome--the link to subclinical inflammation?

BACKGROUND

The role of resistin, a "new" white adipose tissue hormone, still needs to be established. Its linkage to insulin sensitivity and body mass was controversial in previous studies.

MATERIAL/METHODS

Twenty obese patients (BMI: 32.1+/-6.9 kg/m2 ) with obstructive sleep apnoea syndrome (OSAS) (Apnoea-Hypopnoea Index: 48.6+/-19.1, underwent measurements of resistin, interleukin-6 (IL-6), intracellular adhesion molecule-1 (ICAM-1), CRP and the insulin sensitivity index (ISI) by hyperinsulinaemic euglycaemic clamp before, 2 days and 2 months after onset of CPAP treatment.

RESULTS

Resistin remained unchanged during CPAP-therapy and was negatively correlated to ISI (r=-0.359; p=0.006), the latter was significantly improved by CPAP (p<0.001). In a correlation matrix, IL-6 and ICAM-1 were significantly (p=0.001) correlated to resistin (p=0.614 and 0.427). Changes of inflammatory markers under CPAP treatment were related to AHI, as well as resistin changes.

CONCLUSIONS

In agreement with previous investigations, we could only demonstrate a weak linkage between ISI and resistin. However, at least in obese patients with OSAS, there is a close relation to subclinical inflammation (IL-6) and endothelial activation (ICAM-1).

[T cell immunity analysis in children with obstructive sleep apnea syndrome]

OBJECTIVE

To probe into the possible impact on T cell immunity in children with obstructive sleep apnea syndrome (OSAS).

METHOD

Lymphocytes in peripheral blood vessel of children with OSAS vs normal controls were checked by APAAP method and analyzed statistically.

RESULT

The comparison with the controls showed that CD3+ had no significant difference (P>0.05), CD4+, CD4+/CD8+ were significantly lower, CD8+ was significantly higher in children with OSAS (P<0.01), and the analysis of the LSaO2 and period of history showed that the lower the LSaO2, and the longer the period of history, the more effect to CD4+, CD8+, CD3+/CD8+ (P<0.05).

CONCLUSION

T cell immunity are impaired in children with OSAS.

Differential gene expression in the T-helper lymphocytes of obstructive sleep apnea patients treated with nasal continuous positive airway pressure (nCPAP)

Obstructive sleep apnea (OSA) is a disease with significant morbidity, increased risk of accidents attributed to daytime somnolence, and has been associated with cardiovascular complications. The treatment of choice for OSA is nasal continuous positive airway pressure (nCPAP). Some OSA patients, however, are unable to benefit from this therapy as they find nCPAP intolerable due to the related nasal inflammation. It is hypothesized that nCPAP may cause nasal inflammation in these patients by inducing changes in the expression of genes that encode interleukins (IL-3, IL-4, IL-6, IL-8, IL-13) or adhesion molecules (i.e., ICAM-1) in T-helper lymphocytes. An understanding of the underlying inflammatory mechanism could lead to specific interventions that render nCPAP therapy tolerable for these individuals.

Sleep apnea: a model for studying cytokines, sleep, and sleep disruption

Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder, characterized by repeated disruptions of breathing during sleep. The sleep fragmentation and accompanying hypoxemia lead to many negative consequences including cardiac arrhythmias, nocturnal hypertension, confusion, cognitive impairment, daytime sleepiness, as well as depressive symptoms. From the perspective of psychoneuroimmunology (PNI), OSA holds promise as a model for studying sleep and cytokines because of its many relevant characteristics, including neuroimmune interactions, mood changes, and behaviors that directly affect the course of the disorder. In this minireview we briefly summarize the existing literature on cytokines and sleep and then discuss work on cytokines and OSA. We believe that the study of OSA presents researchers with an excellent opportunity to tease apart the many complex and interwoven components of sleep that are relevant to PNI.

Inflammation and obstructive sleep apnea syndrome pathogenesis: a working hypothesis

Obstructive sleep apnea syndrome (OSAS) afflicts about 5% of adults in Western countries and is thought to play an important role in the pathogenesis of cardiovascular disorders and diabetes mellitus. Although the etiology of OSAS is uncertain, intense local and systemic inflammation are present in these patients. In the upper airway, this process may promote oropharyngeal inspiratory muscle dysfunction and amplify upper airway narrowing and collapsibility thereby worsening the frequency and duration of apneas during sleep. The presence of systemic inflammation, characterized by elevated levels of certain potent pro-inflammatory mediators, such as C-reactive protein, leptin, TNF-alpha, IL-1beta, IL-6, reactive oxygen species and adhesion molecules, may predispose to the development of cardiovascular complications observed in patients with OSAS. Treatment with nasal CPAP abrogates, in part, local and systemic inflammation in these patients. Whether therapeutic interventions aimed at abating inflammation could be a useful adjunct in the treatment of OSAS merits further investigation.

The Effect of Surgical Treatment of Obstructive Sleep Apnea Syndrome on the Plasma TNF-.ALPHA. Levels

Obstructive sleep apnea syndrome (OSAS) is defined as intermittent complete or partial upper airway obstruction during sleep, causing mental and physical effects. Both the local and systemic inflammation observed in OSAS induce certain potent pro-inflammatory mediators, which may contribute to the development of cardiovascular consequences. The present study was designed to evaluate the plasma levels of TNF-alpha, which is one of the known pro-inflammatory cytokines, in patients with OSAS and to assess the effect of surgical treatment on the levels of TNF-alpha levels. Twenty seven patients diagnosed to have OSAS, 7 non-apneic patients with chronic tonsillitis (non-OSAS patients), and 4 healthy subjects were enrolled in this study. Blood samples were collected one week preoperatively and postoperatively, and the plasma TNF-alpha levels were measured using high-sensitivity ELISA. The plasma TNF-alpha levels in patients with OSAS were significantly elevated in comparison to normal healthy subjects. In contrast, there was no difference between the patients with non-OSAS and healthy subjects. Moreover, the surgical treatment to enlarge the upper airway in patients with OSAS significantly decreased the levels of TNF-alpha levels. Surgical treatment of patients with OSAS reduces the plasma TNF-alpha levels, thereby ameliorating the systemic inflammation and preventing the development of cardiovascular consequences.

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

The levels of some pro- and anti-inflammatory cytokines [interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha, IL-6, IL-10, and transforming growth factor (TGF)-beta], were measured by enzyme-linked immunosorbent assay (ELISA) method in the plasma of patients affected by obstructive sleep apnea syndrome (OSAS) at 22:00 hours before polysomnographic recording and immediately after the first obstructive apnea causing an SaO2 below 85%. Significantly higher levels of TNF-alpha were found in OSAS patients assessed before polysomnography compared with the control group (P < 0.01). A slight but significant increase in the plasma levels of IL-6 was also present (P < 0.05). Conversely, a significant decrease in the plasma levels of IL-10 was evident at baseline in OSAS patients (P < 0.04). No significant difference emerged between the mean values of IL-1alpha and TGF-beta between OSAS patients and controls. The present data support a prevailing activation of the Th1-type cytokine pattern in OSAS patients, which is not associated with the severity and duration of OSAS. This can have important consequences for the outcome of OSAS patients, especially with regard to the increased risk for developing atherosclerosis and cardiovascular and cerebrovascular diseases. Immediately after the first obstructive apnea causing an SaO2 <85%, a significant variation was observed in the plasma levels of TNF-alpha in OSAS patients compared with those measured before the beginning of polysomnographic recording (P < 0.001). The role played by this further increase in TNF-alpha levels after the obstructive apnea in OSAS patients remains to be established in the light of the pathogenic mechanisms of this sleep disorder.

Phenotypic and functional characterization of blood gammadelta T cells in sleep apnea

Hypoxia-induced lymphocyte dysfunction may be implicated in endothelial cell damage in obstructive sleep apnea (OSA) syndrome. gammadelta 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 gammadelta T cells in patients with OSA and control subjects. The following is a summary of our major findings regarding OSA gammadelta 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)-alpha and interleukin-8 was increased, and the content of the antiinflammatory cytokine interleukin-10 was decreased; (3) gammadelta T cells of patients with OSA adhered significantly more avidly to nonactivated endothelial cells in culture than those of control subjects; (4) L-selectin expression was higher; (5) anti-E/P-selectin antibodies and anti-TNF-alpha antibodies decreased the adhesion index of OSA gammadelta T lymphocytes/endothelial cells but not of control subjects; and (6) cytotoxicity of OSA gammadelta T lymphocytes against endothelial cells in culture was 2.5-fold higher than that of control subjects and could be prevented by pretreatment with anti-TNF-alpha. Collectively these data implicate gammadelta T lymphocyte function in atherogenic sequelae in OSA.

Elevated levels of C-reactive protein and interleukin-6 in patients with obstructive sleep apnea syndrome are decreased by nasal continuous positive airway pressure

BACKGROUND

C-reactive protein (CRP) and interleukin (IL)-6 are important risk factors for atherosclerosis and coronary heart disease. In the present study, we examined serum levels of CRP and IL-6, IL-6 production by monocytes, and the effect of nasal continuous positive airway pressure (nCPAP) in patients with obstructive sleep apnea syndrome (OSAS).

METHODS AND RESULTS

After polysomnography, venous blood was collected at 5 AM from 30 patients with OSAS and 14 obese control subjects. Serum levels of CRP and IL-6 and spontaneous production of IL-6 by monocytes were investigated. In addition, the effects of 1 month of nCPAP were studied in patients with moderate to severe OSAS. Levels of CRP and IL-6 were significantly higher in patients with OSAS than in obese control subjects (CRP P<0.001, IL-6 P<0.05). IL-6 production by monocytes was also higher in patients with OSAS than in obese control subjects (P<0.01). In patients with OSAS, the primary factors influencing levels of CRP were severity of OSAS and body mass index and those influencing levels of IL-6 were body mass index and nocturnal hypoxia. nCPAP significantly decreased levels of both CRP (P<0.0001) and IL-6 (P<0.001) and spontaneous IL-6 production by monocytes (P<0.01).

CONCLUSIONS

Levels of CRP and IL-6 and spontaneous production of IL-6 by monocytes are elevated in patients with OSAS but are decreased by nCPAP. Therefore, OSAS is associated with increased risks for cardiovascular morbidity and mortality, and nCPAP may be useful for decreasing these risks.

Resolution of dyshidrotic dermatitis of the hand after treatment with continuous positive airway pressure for obstructive sleep apnea

Eczema of the palm and obstructive sleep apnea (OSA) are common disorders. Proinflammatory cytokines and cell adhesion molecules are elevated in both of these disorders. We describe an unusual patient with OSA who had recurrent free remission of dermatitis after treatment with continuous positive airway pressure. We speculate that the resolution of the patient's skin condition may reflect the effects of increased tissue oxygenation during sleep, reduced sleep fragmentation, and/or a reduction in sympathetic tone associated with successful sleep apnea treatment.