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

Associations Between Obstructive Sleep Apnea Syndrome, Dry Eye Disease, and CPAP Usage Among Taiwanese Patients: A Retrospective Analysis

Study Objectives

To evaluate the association between obstructive sleep apnea (OSA) and dry eye disease (DED) and analyze the impact of Continuous Positive Airway Pressure (CPAP) on DED.

Methods

This is a retrospective population-based case-control study. Patients who underwent polysomnography in Taiwan from March 1, 2009, to March 1, 2020, were identified from the database of a sleep center. Patients who were diagnosed with keratoconjunctivitis sicca or tear film insufficiency were included. Patients without data from Schirmer's test, lacking tear break-up time values, or with a history of refractive surgery, Sjögren's syndrome, ocular injuries, or a disability in eyelid closure were excluded. All patients with DED enrolled had DED in both eyes. OSA severity between patients with and without DED was compared.

Results

In total, 86 patients with DED and 86 age-matched patients without DED were enrolled. Significant differences in apnea-hypopnea index values (patients with DED: 29.1 ± 23.4, patients without DED: 17.9 ± 20.2, P < 0.001), OSA severity (P < 0.001), and lowest oxygen saturation (P = 0.040) between patients with and without DED were observed. A multivariate logistic regression model indicated that the use of CPAP was independently associated with DED after adjustments for OSA severity. Patients undergoing CPAP were at greater risk of developing DED than those not undergoing CPAP (Odds ratio: 3.93, 95% confidence interval: 1.47-10.49, P = 0.006).

Conclusion

OSA severity is associated with DED and might be attributed to the use of CPAP.

Evaluation of Serum/Plasma Levels of Interleukins (IL-6, IL-12, IL-17, IL-18, and IL-23) in Adults and Children with Obstructive Sleep Apnea: A Systematic Review, Meta-Analysis, and Trial Sequential Analysis

Obstructive sleep apnea (OSA) is a chronic inflammatory disease characterized by partial or complete upper airway obstruction during sleep. We aimed to evaluate serum/plasma levels of several cytokines (interleukin [IL]-6, IL-12, IL-17, IL-18, and IL-23) in a systematic review meta-analysis in both adults and children with OSA compared with controls. We conducted a comprehensive search of 4 digital databases (PubMed, Web of Science, Scopus, and Cochrane Library) up until October 19, 2023, without any limitations. For our meta-analysis, we used Review Manager, version 5.3, and displayed the data as the standardized mean difference (SMD) and 95% confidence interval (CI) to assess the correlation between cytokine levels and OSA. We utilized Comprehensive Meta-Analysis version 3.0 software to conduct bias analyses, meta-regression, and sensitivity analyses. From 1881 records, 84 articles were included in the systematic review and meta-analysis. In adults, the pooled SMDs for IL-6 level were 0.79 (P value < 0.00001), for IL-17 level were 0.74 (P value = 0.14), and for IL-18 level were 0.43 (P value = 0.00002). In children, the pooled SMD for IL-6 was 1.10 (P value < 0.00001), for IL-12 was 0.47 (P value = 0.10), for IL-17 was 2.21 (a P value = 0.24), for IL-18 was 0.19 (P value = 0.07), and for IL-23 was 2.46 (P value < 0.0001). The subgroup analysis showed that the ethnicity, mean body mass index, and mean apnea-hypopnea index for IL-6 levels in adults and the ethnicity for IL-6 levels in children were effective factors in the pooled SMD. The findings of the trial sequential analysis revealed that adequate evidence has been obtained. The analysis of IL levels in adults and children with OSA compared with those without OSA revealed significant differences. In adults, IL-6 and IL-18 levels were significantly higher in the OSA group, while in children, only IL-6 and IL-23 levels were significantly elevated.

Obstructive sleep apnea and bladder pain syndrome/interstitial cystitis in women

PURPOSE

The relationship between obstructive sleep apnea (OSA) and bladder pain syndrome/interstitial cystitis (BPS/IC) remains uncertain. Therefore, this study aimed to compare the frequency of BPS/IC seen in women diagnosed with OSA and in women without OSA.

MATERIAL AND METHODS

The study included a patient group of women with OSA and a control group of women without OSA. All the study participants were administered the Berlin Questionnaire, Epworth Sleepiness Scale, Interstitial Cystitis Symptom Index (ICSI), and the Interstitial Cystitis Problem Index (ICPI). Differences between the women with OSA and the control group were examined.

RESULTS

The study sample consisted of 46 women with OSA and 46 controls. No significant difference was determined between the OSA and control groups concerning age and body mass index (p = 0.810, p = 0.060, respectively). The ESS was greater in the OSA group than in the control group (p = 0.007). The median (IQR) ICSI was 8 (4-11.25) in women with OSA and 5 (1.75-7.15) in controls (p < 0.001). The median (IQR) ICPI was 7 (6.00-10.25) in women with OSA and 6 (1.75-8.00) in controls (p < 0.001).  CONCLUSIONS: The ICSI symptoms and subsequent problems in daily life caused by the symptoms (ICPI) were experienced at a higher rate in patients with OSA than in the control group. There is an association between BPS/IC and OSA.

Association of Tumor Necrosis Factor-Alpha, Interleukin-1β, Interleukin-8, and Interferon-γ with Obstructive Sleep Apnea in Both Children and Adults: A Meta-Analysis of 102 Articles

Background: Cytokines may have a significant impact on sleep regulation. In this meta-analysis, we present the serum/plasma levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-8, IL-1β, and interferon-gamma (IFN-γ) in both children and adults with obstructive sleep apnea (OSA) in comparison to controls. Methods: Four electronic databases were systematically searched (PubMed, Web of Science, Scopus, and Cochrane Library) through 19 October 2023, without any restrictions on language, date, age, and sex. We used Review Manager version 5.3 to perform meta-analysis and presented the data as standardized mean difference (SMD) and 95% confidence interval (CI) values to evaluate the relationships between the levels of cytokines and OSA. Results: A total of 102 articles (150 independent studies) were included in the meta-analysis. The pooled SMDs in adults were 1.42 (95%CI: 1.11, 1.73; p < 0.00001), 0.85 (95%CI: 0.40, 1.31; p = 0.0002), 0.69 (95%CI: 0.22, 1.16; p = 0.004), and 0.39 (95%CI: -0.37, 1.16; p = 0.31) for TNF-α, IL-8, IL-1β, and IFN-γ, respectively. The pooled SMDs in children were 0.84 (95%CI: 0.35, 1.33; p = 0.0008), 0.60 (95%CI: 0.46, 0.74; p < 0.00001), 0.25 (95%CI: -0.44, 0.93; p = 0.49), and 3.70 (95%CI: 0.75, 6.65; p = 0.01) for TNF-α, IL-8, IL-1β, and IFN-γ, respectively. Conclusions: The levels of proinflammatory cytokines of TNF-α, IL-8, and IL-1β in adults, and TNF-α, IL-8, and IFN-γ in children with OSA, are significantly higher than those in controls.

Obstructive sleep apnea: Beyond the dogma of obesity!

Obstructive sleep apnea (OSA) has long been studied in patients with obesity and type 2 diabetes mellitus (T2DM), due to the fact that both disorders are commonly associated with an increased body mass index (BMI). However, a link between OSA and non-obese diabetic patients is still not very elaborated, nor heavily explored. In this review, we elucidate some proposed mechanisms for the link between OSA and diabetic patients both with and beyond obesity, shedding the light on the latter case. One such mechanism is oxidative stress, a phenomenon of reactive oxygen species (ROS) imbalance seen in both of the previously mentioned disorders. A plausible explanation for the OSA-induced ROS production is the repeating episodes of hypoxia and reperfusion and their effect on the mitochondrial electron transport chain. This paper explores the literature regarding ROS imbalance as the possible missing link between OSA and Diabetes Mellitus beyond obesity, while still mentioning other possible proposed mechanisms such as a dysregulated autonomic nervous system (ANS), as well as mechanical and craniofacial abnormalities. This paper also suggests a link between OSA and diabetic complications, while exploring the clinical progress made in treating the former disorder with anti-oxidant and hypo-glycemic drugs. If further investigated, these findings could help identify novel therapeutic interventions for the treatment of OSA and Diabetic patients.

Increased Levels of VCAM-1 in Patients with High Cardiovascular Risk and Obstructive Sleep Apnea Syndrome

(1) Background: Although obstructive sleep apnea (OSA) is associated with increased cardiovascular morbidity, the link between OSA and cardiovascular disease (CVD) is not completely elucidated. Thus, we aim to assess cardiovascular risk (CVR) using SCORE 2 and SCORE 2 for older persons (SCORE 2OP), and to evaluate the association between the endothelial biomarkers VCAM-1, ICAM-1, epicardial fat, and sleep study parameters in order to improve current clinical practices and better understand the short-and long-term CVRs in OSA patients. (2) Methods: 80 OSA patients and 37 healthy volunteers were enrolled in the study. SCORE2 and SCORE 2 OP regional risk charts (validated algorithms to predict the 10-year risk of first-onset CVD) were used for the analysis of CVR. Two-dimensional echocardiography was performed on all patients and epicardial fat thickness was measured. VCAM-1 and ICAM-1 serum levels were assessed in all patients. (3) Results: OSA patients were classified as being at high CVR, regardless of the type of score achieved. Increased EFT was observed in the OSA group. VCAM-1 was associated with a high CVR in OSA patients, but no significant correlation was observed between adhesion molecules and epicardial fat thickness. (4) Conclusions: OSA patients have a high CVR according to the SCORE 2 and SCORE 2OP risk scores. VCAM-1 may be associated with a high CVR in OSA patients. Extending conventional risk stratification scores by adding other potential biomarkers improves the risk stratification and guide treatment eligibility for CVD prevention in the OSA population.

Genetic association between coffee/caffeine consumption and the risk of obstructive sleep apnea in the European population: a two-sample Mendelian randomization study

BACKGROUND

The association between coffee/caffeine consumption and obstructive sleep apnea (OSA) risk remains unclear.

PURPOSE

To determine the relationship between coffee/caffeine consumption and the risk of OSA, using the Mendelian randomization (MR) method in the European population.

METHODS

Two sets of coffee consumption-associated genetic variants were, respectively, extracted from the recent genome-wide meta-analysis (GWMA) and genome-wide association study (GWAS) of coffee consumption. Taking other caffeine sources into account, genetic variants associated with caffeine consumption from tea and plasma caffeine (reflecting total caffeine intake) were also obtained. The inverse variance weighted (IVW) technique was utilized as the primary analysis, supplemented by the MR-Egger, weighted-median, and MR-Pleiotropy RESidual Sum and Outlier (PRESSO) techniques. Leave-one-out (LOO) analysis was performed to assess whether the overall casual estimates were driven by a single SNP. Additional sensitivity analyses were performed using similar methods, while the genetic variants associated with confounders, e.g., body mass index and hypertension, were excluded.

RESULTS

The IVW method demonstrated that coffee consumption GWMA (OR: 1.065, 95% CI 0.927-1.224, p = 0.376), coffee consumption GWAS (OR: 1.665, 95% CI 0.932-2.977, p = 0.086), caffeine from tea (OR: 1.198, 95% CI 0.936-1.534, p = 0.151), and blood caffeine levels (OR: 1.054, 95% CI 0.902-1.231, p = 0.508) were unlikely to be associated with the risk of OSA. The other three methods presented similar results, where no significant associations were found. No single genetic variant was driving the overall estimates by the LOO analysis. These findings were also supported by the sensitivity analyses with no confounding genetic variants.

CONCLUSION

Our study found no association between coffee/caffeine consumption and the risk of OSA.

Multi-Omics Analysis of Circulating Exosomes in Adherent Long-Term Treated OSA Patients

Obstructive sleep apnea (OSA) is a highly prevalent chronic disease affecting nearly a billion people globally and increasing the risk of multi-organ morbidity and overall mortality. However, the mechanisms underlying such adverse outcomes remain incompletely delineated. Extracellular vesicles (exosomes) are secreted by most cells, are involved in both proximal and long-distance intercellular communication, and contribute toward homeostasis under physiological conditions. A multi-omics integrative assessment of plasma-derived exosomes from adult OSA patients prior to and after 1-year adherent CPAP treatment is lacking. We conducted multi-omic integrative assessments of plasma-derived exosomes from adult OSA patients prior to and following 1-year adherent CPAP treatment to identify potential specific disease candidates. Fasting morning plasma exosomes isolated from 12 adult patients with polysomnographically-diagnosed OSA were analyzed before and after 12 months of adherent CPAP therapy (mean ≥ 6 h/night) (OSAT). Exosomes were characterized by flow cytometry, transmission electron microscopy, and nanoparticle tracking analysis. Endothelial cell barrier integrity, wound healing, and tube formation were also performed. Multi-omics analysis for exosome cargos was integrated. Exosomes derived from OSAT improved endothelial permeability and dysfunction as well as significant improvement in tube formation compared with OSA. Multi-omic approaches for OSA circulating exosomes included lipidomic, proteomic, and small RNA (miRNAs) assessments. We found 30 differentially expressed proteins (DEPs), 72 lipids (DELs), and 13 miRNAs (DEMs). We found that the cholesterol metabolism (has04979) pathway is associated with lipid classes in OSA patients. Among the 12 subjects of OSA and OSAT, seven subjects had complete comprehensive exosome cargo information including lipids, proteins, and miRNAs. Multi-omic approaches identify potential signature biomarkers in plasma exosomes that are responsive to adherent OSA treatment. These differentially expressed molecules may also play a mechanistic role in OSA-induced morbidities and their reversibility. Our data suggest that a multi-omic integrative approach might be useful in understanding how exosomes function, their origin, and their potential clinical relevance, all of which merit future exploration in the context of relevant phenotypic variance. Developing an integrated molecular classification should lead to improved diagnostic classification, risk stratification, and patient management of OSA by assigning molecular disease-specific therapies.

Obstructive sleep apnea in Parkinson's disease: A prevalent, clinically relevant and treatable feature

Parkinson's disease (PD) is a chronic neurodegenerative disease characterized by motor and non-motor symptoms, including obstructive sleep apnea (OSA), a common comorbid sleep disorder. The prevalence of OSA in PD is high, and its impact on quality of life, accident risk, and limited treatment options underscores the need for vigilant monitoring and effective interventions. OSA is observed in 20-70% of PD patients, whereas the general population exhibits a lower prevalence ranging from 2 to 14%. These discrepancies in prevalence may be attributed to differences in demographic characteristics, sample sizes with selection bias, and variations in scoring systems for apnea and hypopnea events used across different studies. This review highlights the potential pathogenesis of comorbid OSA in PD and provides an overview of ongoing clinical trials investigating interventions for this condition. Several mechanisms have been implicated in the development of OSA in PD, including intermittent hypoxemia, sleep fragmentation, alterations in the glymphatic system homeostasis, upper airway obstruction, and inflammation. Given the adverse effects of PD comorbid OSA, early intervention measures are crucial. It is imperative to conduct longitudinal studies and clinical trials to elucidate the pathogenesis and develop novel and effective interventions for OSA in PD patients. These efforts aim to delay the progression of PD, enhance patients' quality of life, and alleviate the burden on society and families.

The effects of intermittent hypoxia on hepatic expression of fatty acid translocase CD36 in lean and diet-induced obese mice

BACKGROUND

Both obstructive sleep apnea (OSA) and non-alcoholic fatty liver disease (NAFLD) are prevalent within obese individuals. We aimed to investigate the effects of intermittent hypoxia (IH), a clinical feature of OSA, on hepatic expression of fatty acid translocase (CD36) in relation to liver injury in lean and diet-induced obese mice.

METHODS

Four-week-old male C57BL/6J mice were randomized to standard diet (SD) or high fat (HF) diet groups. At 13-week-old, all mice were exposed to either air or IH (IH30; thirty hypoxic episodes per hour) for four weeks. We assessed liver injury through lipid profile, oxidative and inflammatory stress, histological scoring and hepatic CD36 expression.

RESULTS

In lean mice, IH elevated serum and hepatic triglyceride and free fatty acid (FFA) levels, in line with upregulation of hepatic CD36 expression and myeloperoxidase (MPO)-positive cells in support of inflammatory infiltrates along with increase in serum malondialdehyde (MDA), C-X-C motif chemokine ligand 1(CXCL-1) and monocyte chemoattractant protein-1 (MCP-1). In diet-induced obese mice, an increase in hepatic alanine transaminase (ALT) activity, serum and hepatic levels of lipid parameters and inflammatory markers, serum MDA level, hepatic expressions of CD36 and α-smooth muscle actin (α-SMA), and MPO-positive cells was observed. IH potentiated hepatic ALT activity, serum CXCL-1 and hepatic interleukin-6 (IL-6), in line with inflammatory infiltrates, but paradoxically, reduced hepatic FFA level and hepatic CD36 expression, compared to obese mice without IH exposure. However, IH further augmented diet-induced liver steatosis and fibrosis as shown by histological scores.

CONCLUSION

This study contributes to support that IH featuring OSA may lead to liver injury via differential regulation of hepatic CD36 expression in lean and diet-induced obese mice.

Relationship between severity of obstructive sleep apnea and benign prostatic hyperplasia

PURPOSE

The cause of benign prostatic hyperplasia (BPH) is controversial, local hypoxia and inflammation being the main two possibilities proposed. The aim of this study was to evaluate the relationship between obstructive sleep apnea (OSA) and BPH.

METHODS

The study cohort comprised men from January 2016 to December 2020 in our Sleep Center. These patients were classified into four groups (no, mild, moderate, severe OSA) by apnea-hypopnea indexes (AHI). Logistic regression was used to identify independent risk factors for BPH, after which participants were stratified into younger (age ≤ 40 years) and older groups (age > 40 years) for further analysis.

RESULTS

The study cohort comprised 467 patients including 135 younger subjects and 332 older subjects. The prevalence of BPH in the above listed AHI categories was 37.5%, 55.0%, 62.9%, and 52.3%, respectively (p = 0.075). Logistic regression analysis of all patients identified age as a risk factor for BPH (p < 0.001). Stratified analysis according to AHI category found a prevalence of BPH of 0.0%, 13.0%, 33.3%, and 43.9%, respectively, in younger group (p = 0.006), and 52.2%, 71.9%, 71.1%, and 56.3%, respectively, in older group (p = 0.038). Logistic regression analysis found age and AHI were independent risk factors for BPH in younger group (both p < 0.05), whereas only age was identified as a risk factor for BPH in older group (p < 0.001).

CONCLUSIONS

Age is an independent risk factor for BPH in men with OSA. AHI is also an independent risk factor for BPH in younger men, suggesting that OSA may affect development of BPH in younger men.

Potential Diagnostic and Monitoring Biomarkers of Obstructive Sleep Apnea-Umbrella Review of Meta-Analyses

Obstructive sleep apnea (OSA) is a prevalent, underdiagnosed disease that imposes a significant impact on the health and wellbeing of patients and a financial burden on individuals, their families, and society. Development of new methods of testing other than an overnight sleep study, such as measurement of serum or plasma biomarkers, may provide an easier diagnostic process to identify patients with OSA and allow earlier initiation of treatment, which might prevent serious comorbidities. We conducted a systematic review and quality assessment of available meta-analyses regarding potential diagnostic and monitoring biomarkers of obstructive sleep apnea. A total of 14 sets of candidate biomarkers displayed differences in levels or concentrations in OSA patients compared to non-OSA controls, and decreased after OSA treatment: CRP, IL-6, TNF-α, Il-8, HCY, ICAM-1, VCAM-1, VEGF, TC, LDLc, HDLc, TG, leptin, MDA, ALT, AST, IGF-1, adiponectin, and cortisol. This review summarizes the evidence for OSA-associated potential biomarkers and demonstrates that the quality of available studies, as measured by AMSTAR2, is often low and associated with a high risk of bias.

A Case-Control Study on the Changes in High-Sensitivity C-Reactive Protein and Tumor Necrosis Factor-Alpha Levels with Surgical Treatment of OSAS

Obstructive sleep apnea syndrome (OSAS) is a common but underdiagnosed condition with significant health and economic implications for society. Inflammatory mediators are proposed to be associated with the presence and severity of OSAS and contribute to morbidity and mortality. This paper details a prospective non-randomized case control study of a cohort of subjects, who underwent surgical treatment of OSAS and were enrolled to assess the sleep parameters and blood levels of selected inflammatory markers at pre-operative and post-operative time points, also comparing them to the levels in a control group. A total of 25 study subjects and 18 control subjects were enrolled. Median values and interquartile range (IQR) of the apnea-hypopnea index (AHI) in the study group pre-operatively and post-operatively were 34 (18.5-45.5) and 13.3 (7.5-27.3), while in the control group 1.4 (1.0-2.1) per hour. The mean (IQR) hs-CRP levels (mg/L) were 1.782 (0.941-5.594) and 1.980 (0.990-5.445) in the study group, pre-operatively and post-operatively, respectively, while 0.891 (0.767-1.436) in the control group. The mean (IQR) TNF-α levels (pg/mL) were 7.999 (6.137-9.216) and 6.614 (5.534-7.460) pre-and post-operatively, respectively, and were 6.000 (5.026-6.823) in the control group. Results demonstrated that both inflammatory markers, hs-CRP and TNF-α, are higher in subjects with OSAS compared to the controls, and their levels decrease, but are still higher than the controls, after successful surgical treatment. Further analysis including the body mass index and age demonstrated that these changes were significant for TNF-α, but not hs-CRP.

Later sleep timing and social jetlag are related to increased inflammation in a population with a high proportion of OSA: findings from the Cleveland Family Study

STUDY OBJECTIVES

To examine the association between sleep midpoint and inflammation in a population with a large proportion of individuals diagnosed with obstructive sleep apnea syndrome (OSAS), a group that is already prone to increased inflammation.

METHODS

Subjects from the Cleveland Family Study underwent overnight polysomnography and completed surveys on sleep habits. Morning and evening blood samples were collected and assayed for proinflammatory biomarkers interleukin (IL)-1, IL-6, and tumor necrosis factor α (TNF-α). Linear regression models were used, adjusting for potential confounders and sleep duration.

RESULTS

The study population included 587 adults (52.3% with OSAS). Mean ± standard deviation weekday sleep midpoint was 3.52 ± 2.09 (3:31 am) and weekend sleep midpoint was 4.46 ± 1.69 (4:28 am). The Mean difference between weekday and weekend sleep midpoint (social jetlag) was 0.94 ± 2.08 hours. After adjusting for OSA severity, greater social jetlag was associated with higher levels of the inflammatory cytokine IL-1 (beta: 0.435 pg/mL, 95% confidence interval [CI]: 0.091 to 0.779). Additionally, later timing of sleep during both the weekdays and the weekends was associated with increased levels of IL-6 (weekday beta: 0.182 pg/mL; 95% CI: 0.013 to 0.350; and weekend beta: 0.188 pg/mL; 95% CI: 0.004 to 0.373). No trends were observed with TNF-α and any sleep exposure.

CONCLUSIONS

Later sleep timing was associated with elevated levels of IL-6 while increased social jetlag was associated with elevated levels of IL-1. Our results indicate that later sleep schedules and increased social jetlag may lead to higher inflammation, even after controlling for OSA severity.

CITATION

Girtman KL, Baylin A, O'Brien LM, Jansen EC. Later sleep timing and social jetlag are related to increased inflammation in a population with a high proportion of OSA: findings from the Cleveland Family Study. J Clin Sleep Med. 2022;18(9):2179-2187.

Effects of oral appliances on serum cytokines in adults with obstructive sleep apnea: a systematic review

PURPOSE

This review aimed to evaluate the effects of oral appliance (OA) therapy on serum inflammatory cytokines in adults diagnosed with obstructive sleep apnea (OSA).

METHODS

Seven electronic databases and partial gray literature were searched without restrictions through March 2021. Articles evaluating the levels of serum inflammatory cytokines in patients with OSA after OA treatment were included. The risk of bias (RoB) was assessed using the before-and-after tool or RoB 2.0. The level of certainty was assessed using the GRADE tool.

RESULTS

Five studies met the eligibility criteria. One was a randomized clinical trial (RCT), while four were non-randomized clinical trials (NRCTs). Among the studies, C-reactive protein (CRP), IL-6, IL-10, IL-1β, and tumor necrosis factor α (TNF-α) were investigated. The RCT reported no significant differences in marker levels after 2 months of OA therapy, while the NRCTs showed improvement on CRP, TNF-α, and IL-1β levels after longer follow-up periods. The RoB was evaluated as showing some concern in the RCT. Three NRCTs presented good RoB, and one showed a fair RoB. The level of certainty was graded as moderate quality for inflammatory marker levels assessed in the RCT The levels of certainty evaluated in NRCTs were classified as very low.

CONCLUSIONS

Although limited, existing scientific evidence showed that OA therapy may improve serum cytokine levels in adults with OSA. However, short treatment periods are not effective in reducing markers of systemic inflammation which may require extended time and a decrease of in apneic events to improve.

Improved Inflammatory and Cardiometabolic Profile After Soft-Tissue Sleep Surgery for Obstructive Sleep Apnea: A Systematic Review and Meta-analysis

Importance

Obstructive sleep apnea (OSA) is associated with a rise in serum inflammatory markers, which may be attenuated by sleep surgery.

Objective

To evaluate whether sleep surgery was associated with improved levels of proinflammatory markers in adults with OSA.

Data Sources

Two authors independently searched Cochrane, Embase, and PubMed databases from inception through June 14, 2022.

Study Selection

Two authors searched the Cochrane, Embase, and PubMed databases for studies comparing preoperative and postoperative levels of serum biomarkers in patients undergoing sleep surgery.

Data Extraction and Synthesis

Data were extracted from included articles into a structured proforma. Meta-analyses of the standardized mean difference (SMD) were conducted in random-effects models. To ensure relevance to clinicians and patients, the probability of benefit and number needed to treat were calculated for outcomes that demonstrated a statistically significant effect after sleep surgery.

Main Outcomes and Measures

The primary outcome was the preoperative and postoperative levels of serum biomarkers in patients undergoing sleep surgery, including C-reactive protein (CRP), glucose, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and interleukin-6 (IL-6). Data analysis was performed from April to May 2022.

Results

Of the 3218 studies screened, 26 studies with 1187 patients (mean [SD] age, 42.8 [11.1] years; 932 [78.5%] men and 255 [21.5%] women) were included. Soft-tissue sleep surgery was associated with a large decrease in CRP (SMD, -0.377; 95% CI, -0.617 to -0.137), total cholesterol (SMD, -0.267; 95% CI, -0.417 to -0.116), LDL (SMD, -0.201; 95% CI, -0.344 to -0.058), IL-6 (SMD, -1.086; 95% CI, -1.952 to -0.221), tumor necrosis factor-α (SMD, -0.822; 95% CI, -1.617 to -0.027), triglyceride (SMD, -0.186; 95% CI, -0.301 to -0.071), and leptin (SMD, -0.519; 95% CI, -0.954 to -0.083) in patients with OSA. Meta-regression highlighted that increased age, higher preoperative score for cumulative sleep time percentage with oxyhemoglobin saturation less than 90% (CT90), and greater change in CT90 postoperatively were associated with a greater decrease in serum CRP levels after soft-tissue sleep surgery. A greater reduction in apnea hypopnea index (AHI) was strongly associated with a greater reduction in total cholesterol and LDL. A greater reduction in body mass index and AHI were also associated with a greater increase in HDL.

Conclusions and Relevance

The findings of this systematic review and meta-analysis of 26 studies suggest that sleep surgery is associated with decreased levels of CRP, total cholesterol, LDL, triglyceride, IL-6, leptin, and TNF-α, which may improve the inflammatory and cardiometabolic profile of patients who undergo sleep surgery.

Causal analysis between altered levels of interleukins and obstructive sleep apnea

Background

Inflammation proteins including interleukins (ILs) have been reported to be related to obstructive sleep apnea (OSA). The aims of this study were to estimate the levels for several key interleukins in OSA and the causal effects between them.

Method

Weighted mean difference (WMD) was used to compare the expression differences of interleukins between OSA and control, and the changed levels during OSA treatments in the meta-analysis section. A two-sample Mendelian randomization (MR) was used to estimate the causal directions and effect sizes between OSA risks and interleukins. The inverse-variance weighting (IVW) was used as the primary method followed by several other MR methods including MR Egger, Weighted median, and MR-Robust Adjusted Profile Score as sensitivity analysis.

Results

Nine different interleukins—IL-1β, IL-2, IL-4, IL-6, IL-8, IL-12, IL-17, IL-18, and IL-23—were elevated in OSA compared with control to varying degrees, ranging from 0.82 to 100.14 pg/ml, and one interleukin, IL-10, was decreased by 0.77 pg/ml. Increased IL-1β, IL-6, and IL-8 rather than IL-10 can be reduced in OSA by effective treatments. Further, the MR analysis of the IVW method showed that there was no significant evidence to support the causal relationships between OSA and the nine interleukins—IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-17, and IL-18. Among them, the causal effect of OSA on IL-5 was almost significant [estimate: 0.267 (−0.030, 0.564), p = 0.078]. These results were consistent in the sensitivity analysis.

Conclusions

Although IL-1β, IL-2, IL-4, IL-6, IL-8, IL-12, IL-17, IL-18, and IL-23 were increasing and IL-10 was reducing in OSA, no significant causal relationships were observed between them by MR analysis. Further research is needed to test the causality of OSA risk on elevated IL-5 level.

Obstruktive Schlafapnoe und arterielle Hypertonie

Hintergrund

In Deutschland leiden rund 19 Mio. Patienten an einer diagnostizierten arteriellen Hypertonie (aHT). Die Schnittmenge zwischen Menschen mit aHT und obstruktiver Schlafapnoe (OSA) ist groß. Aufwachreaktionen und Hypoxämie im Rahmen einer OSA können zu einem gesteigerten Sympathikotonus und endothelialer Dysfunktion und somit zu aHT führen.

Fragestellung

Der vorliegende Übersichtsartikel soll die Zusammenhänge zwischen OSA und aHT sowie Behandlungsmöglichkeiten darstellen.

Materialien und Methoden

Es erfolgte eine Literaturrecherche von Original- und Übersichtsartikeln, die bis 2021 in der PubMed-Datenbank veröffentlicht wurden.

Ergebnisse

Obstruktive Schlafapnoe kann sowohl die Entstehung als auch die Verschlechterung einer aHT verursachen. Betroffene profitieren von einer CPAP-Behandlung mit einer durchschnittlichen Senkung des systolischen Blutdrucks um −4,4 mm Hg sowie des diastolischen Blutdrucks um −2,9 mm Hg. Prädiktoren für eine Reduktion des Blutdrucks unter kontinuierlicher Positivdrucktherapie (CPAP) sind junges Alter, therapieresistente aHT, schwere OSA-bedingte Sauerstoffentsättigungen und ein „Non-Dipping-Blutdruckmuster“.

Schlussfolgerung

Die adäquate Behandlung einer aHT fordert häufig einen multimodalen Ansatz. Neben einer medikamentösen antihypertensiven Therapie und einer Modifikation des Lebensstils sollte auch die Diagnose und gegebenenfalls die Behandlung einer OSA berücksichtigt werden.

Putative associations between inflammatory biomarkers, obesity, and obstructive sleep apnea

BACKGROUND:

Previous studies have reported increased levels of inflammatory mediators in patients with obstructive sleep apnea (OSA), but their relation with the severity of OSA is controversial.

OBJECTIVE:

To address potential relationships between OSA-related inflammatory markers, namely, C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and fibrinogen, with different oxygenation parameters and with BMI.

METHODS:

All eligible patients with suspected OSA newly referred to the Sleep Medicine Research Center at King Abdulaziz University Hospital, Jeddah, were evaluated demographically and anthropometrically, and underwent overnight polysomnography. Fasting morning blood samples were collected to measure serum levels of CRP, fibrinogen, TNF-α, and IL-6. Potential correlations between these inflammatory mediators and severity measures of OSA and body mass index (BMI) were explored.

RESULTS:

Sixty-four patients completed the study (40 with OSA and 24 without OSA). Significantly increased levels of CRP, fibrinogen, IL-6, and TNF-α emerged in patients with OSA compared to non-OSA. Significant associations between log CRP and log fibrinogen levels emerged with increasing BMI. However, there was no significant association between any of the inflammatory markers and the severity of OSA based on the apnea/hypopnea index or oxyhemoglobin saturation-derived parameters.

CONCLUSIONS:

OSA patients exhibit increased levels of inflammatory mediators that do not appear to be associated with polysomnographic measures, but exhibit positive correlation with the degree of adiposity.

Circulating C-reactive protein levels in patients with suspected obstructive sleep apnea

STUDY OBJECTIVES

To assess determinants of CRP in a cohort of patients referred for investigation of OSA and to determine whether overlap of OSA and COPD (overlap syndrome, OVS) is associated with higher levels of CRP.

METHODS

This was a cross-sectional study that included 2352 patients seen at the West Australian Sleep Disorders Research Institute between 2006 and 2010. All patients had circulating CRP levels, and spirometry performed. OSA was defined apnea-hypopnea index (AHI) ≥ 5 events per hour and COPD defined as FEV1/FVC ratio <0.70 and age > 40 years. Univariate and multivariate regression analysis were used to identify CRP determinants.

RESULTS

Mean age was 51 years (60% male), median (AHI) was 27 events/h, median 3% oxygen desaturation index (ODI3%) was 24 events/h, mean FEV₁ was 88% predicted, and median CRP was 3.0 mg/L. In multivariate analyses: age, body mass index, female sex, neck circumference, AHI, and desaturation markers (nadir and mean oxygen saturation) were independently associated with higher CRP. Spirometric variables were not predictors. There was no significant difference in CRP among OSA patients with or without co-existing COPD.

CONCLUSIONS

Markers of OSA severity (AHI and oxygenation), age, BMI, neck circumference and female sex were independent predictors of circulating CRP levels. OSA overlapping with COPD was not associated with increased CRP compared to either condition alone, suggesting other mechanisms for the increased CVD risk in OVS. Identification of factors that predict CRP will help identify patients at higher risk of CVD and aid risk stratification.

Alzheimer's Disease, Sleep Disordered Breathing, and Microglia: Puzzling out a Common Link

Sleep Disordered Breathing (SDB) and Alzheimer's Disease (AD) are strongly associated clinically, but it is unknown if they are mechanistically associated. Here, we review data covering both the cellular and molecular responses in SDB and AD with an emphasis on the overlapping neuroimmune responses in both diseases. We extensively discuss the use of animal models of both diseases and their relative utilities in modeling human disease. Data presented here from mice exposed to intermittent hypoxia indicate that microglia become more activated following exposure to hypoxia. This also supports the idea that intermittent hypoxia can activate the neuroimmune system in a manner like that seen in AD. Finally, we highlight similarities in the cellular and neuroimmune responses between SDB and AD and propose that these similarities may lead to a pathological synergy between SDB and AD.

Association between nocturnal hypoxemic burden and glucose metabolism

PURPOSE

To evaluate the association between a novel integrated event-based and hypoxemia-based parameter of polysomnography (PSG), hypoxemic load or HL100, and fasting blood glucose (FBG) and hemoglobin A1c (HbA1c) levels.

METHODS

Adult patients, who underwent an in-lab PSG at the University of Iowa Hospitals and Clinics with FBG or HbA1c levels, were included. Event-based parameter and hypoxemia-based parameter data were derived. HL100, defined as the integrated area of desaturation between the 100% oxygen saturation and the measured saturation levels during sleep divided by the total sleep time, was calculated by Python software. Demographic data and glycemic parameters within 1 year prior to PSG (FBG and HbA1c) were retrieved from chart review. Spearman correlation analysis and stepwise backward regression analysis were performed to determine independent predictors of FBG and HbA1c levels.

RESULTS

Of the 467 patients who underwent an in-lab PSG, 218 had FBG levels, 84 had HbA1c levels, and 118 had both values. All event-based and hypoxemia-based parameters, including HL100, were significantly correlated to FBG and HbA1c levels. Stepwise backward regression analyses, adjusted for age, sex, body mass index, and diabetes status, revealed that log HL100 was significantly related to FBG (B = 23.9, p = 0.010), but none of log event-based or hypoxemia-based parameters were found to be significantly related HbA1c levels.

CONCLUSIONS

HL100 was shown to be an independent predictor of FBG in this cohort, implying that any degree of desaturation below 100% could adversely affect glucose metabolism. HL100 may be useful for interpretation of sleep studies, risk stratification, and patient management purposes in the future.

Obstructive sleep apnea and severity of nonalcoholic fatty liver disease

BACKGROUND

Mechanisms involving obstructive sleep apnea (OSA) and nonalcoholic fatty liver disease (NAFLD) are under increasing assessment. This study evaluated the correlation of OSA with the severity of NAFLD.

MATERIALS AND METHODS

Prospective study in which patients with at least one of metabolic syndrome (MS) criteria were initially assessed by the NAFLD fibrosis score and according to the outcome (intermediate or high risk of advanced fibrosis) underwent liver biopsy (exception of patients with clinical, ultrasound or endoscopic diagnosis of cirrhosis). All patients performed polysomnography. For statistical analysis, the patients were assembled into two groups: (1) without apnea or mild apnea and (2) moderate or severe apnea. In the correlation of OSA with the severity of NAFLD, the risk factors evaluated were: degree of steatosis, presence and severity of nonalcoholic steatohepatitis (NASH) and fibrosis.

RESULTS

Fifty-one patients were evaluated, 80.4% had systemic arterial hypertension (SAH), 68.6% type 2 diabetes mellitus, 62.7% dyslipidemia and 96.1% MS. Regarding the histological evaluation (n = 48), all had steatosis, 95.8% steatohepatitis and 83.3% fibrosis. In polysomnography, 80.4% were group 1 and 19.6% group 2. In univariate analysis, no correlation was found between steatosis severity, NASH and presence or severity of fibrosis with OSA. A multivariate analysis adjusted for obesity level, found that patients with moderate to severe OSA had an increased risk of hepatic fibrosis (odds ratio 1.22, 95% confidence interval: 1.02-1.45, P = 0.027).

CONCLUSION

The present study demonstrated an association between fibrosis and moderate to severe OSA, regardless of obesity.

Ocular Complications of Obstructive Sleep Apnea

Obstructive sleep apnea (OSA), the most common form of sleep-disordered breathing, is characterized by repetitive episodes of paused breathing during sleep, which in turn induces transient nocturnal hypoxia and hypercapnia. The high prevalence of OSA and its associated health consequences place a heavy burden on the healthcare system. In particular, the consequent episodic oxygenic desaturation/reoxygenation series and arousals from sleep in patients with OSA have the potential to trigger oxidative stress, elevated systemic inflammatory responses, and autonomic dysfunction with sympathetic activation. Given these adverse side-effects, OSA is highly correlated to many eye diseases that are common in everyday ophthalmic practices. Some of these ocular consequences are reversible, but they may permanently threaten a patient’s vision if not treated appropriately. Here, this article seeks to review the ocular consequences and potential pathophysiologic associations in patients with OSA. Understanding these OSA-related eye diseases may help clinicians provide comprehensive care to their patients.

The Role of Obesity in the Immunopathogenesis of COVID-19 Respiratory Disease and Critical Illness

Coronavirus disease (COVID-19), the clinical syndrome caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is currently a global health pandemic with substantial morbidity and mortality. COVID-19 has cast a shadow on nearly every aspect of society, straining health systems and economies across the world. Although it is widely accepted that a close relationship exists between obesity, cardiovascular disease, and metabolic disorders on infection, we are only beginning to understand ways in which the immunological sequelae of obesity functions as a predisposing factor related to poor clinical outcomes in COVID-19. As both the innate and adaptive immune systems are each primed by obesity, the alteration of key pathways results in both an immunosuppressed and hyperinflammatory state. The present review will discuss the cellular and molecular immunology of obesity in the context of its role as a risk factor for severe COVID-19, discuss the role of cytokine storm, and draw parallels to prior viral epidemics such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and 2009 H1N1.

The effect of chronic intermittent hypoxia in cardiovascular gene expression is modulated by age in a mice model of sleep apnea

STUDY OBJECTIVES

Chronic intermittent hypoxia (CIH) is a major determinant in obstructive sleep apnea cardiovascular morbidity and this effect is influenced by age. The objective of the present study was to assess the differential molecular mechanisms at gene-level expression involved in the cardiovascular remodeling induced by CIH according to chronological age.

METHODS

Two- and 18-month-old mice (N = 8 each) were subjected to CIH or normoxia for 8 weeks. Total messenger RNA (mRNA) was extracted from left ventricle myocardium and aortic arch, and gene expression of 46 intermediaries of aging, oxidative stress, and inflammation was measured by quantitative real-time polymerase chain reaction.

RESULTS

Cardiac gene expression of Nrf2 (2.05-fold increase, p < 0.001), Sod2 (1.9-fold increase, p = 0.035), Igf1r (1.4-fold increase, p = 0.028), Mtor (1.8-fold increase, p = 0.06), Foxo3 (1.5-fold increase, p = 0.020), Sirt4, Sirt6, and Sirt7 (1.3-fold increase, p = 0.012; 1.1-fold change, p = 0.031; 1.3-fold change, p = 0.029) was increased after CIH in young mice, but not in old mice. In aortic tissue, endothelial isoform of nitric oxide synthase was reduced in young mice (p < 0.001), Nrf2 was reduced in 80% (p < 0.001) in young mice and 45% (p = 0.07) in old mice, as its downstream antioxidant target Sod2 (82% reduced, p < 0.001). IL33.

CONCLUSIONS

CIH effect in gene expression is organ-dependent, and is modulated by age. CIH increased transcriptional expression of genes involved in cardioprotection and cell survival in young, but not in old mice. In aortic tissue, CIH reduced gene expression related to an antioxidant response in both young and old mice, suggesting vascular oxidative stress and a proaging process.

Does continuous positive airways pressure treatment improve clinical depression in obstructive sleep apnea? A randomized wait-list controlled study

BACKGROUND

Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder that is associated with a range of adverse daytime sequelae, including significantly higher rates of clinical depression than is seen in the general community. Improvements in depressive symptoms occur after treatment of the primary sleep disorder, suggesting that comorbid depression might be an intrinsic feature of OSA. However, there are limited data on whether treatment for OSA in patients diagnosed with clinical depression improves mood symptoms meaningfully enough to lead to the remission of the psychiatric diagnosis.

METHODS

N = 121 untreated OSA patients were randomized to either continuous positive airway pressure (CPAP) treatment or waitlist control, and depressive symptoms, sleepiness and clinical depression (using a structured clinical interview) were assessed at baseline and 4 months. Linear and logistic regression analyses were conducted, controlling for baseline scores, stratification factors and antidepressant use.

RESULTS

Depressive symptoms (odds ratio [OR] = -4.19; 95% confidence interval [CI] = -7.25, -1.13; p = .008) and sleepiness (OR = -4.71; 95% CI = -6.26, -3.17; p < .001) were significantly lower at 4 months in the CPAP group compared to waitlist. At 4 months, there was a significant reduction in the proportion of participants in the CPAP group meeting criteria for clinical depression, compared to the waitlist controls (OR = 0.06, 95% CI = 0.01, 0.37; p = .002).

CONCLUSION

Treatment of OSA may be a novel approach for the management and treatment of clinical depression in those with comorbid sleep disordered breathing. Larger trials of individuals with clinical depression and comorbid OSA are needed.

The effect of apnea management on novel coronavirus infection: A study on patients with obstructive sleep apnea

OBJECTIVE

To assess the frequency of coronavirus disease-2019 (COVID-19) and the effect of obstructive sleep apnea (OSA) management on COVID-19 among patients with confirmed OSA.

DESIGN

Cross-sectional telephone interview survey.

SETTING

Academic sleep labs.

PARTICIPANTS

Iranian adults ≥ 18 years old with confirmed OSA.

RESULTS

Among 275 participants with OSA, 20% (n = 55) were suspected to have history of COVID-19 but had no positive test, and 18% (n = 51) were in the definite COVID-19 group according to their reported symptoms or confirmed positive test. Having severe OSA (apnea hypopnea index ≥ 30) was associated with an increased risk of definite COVID-19, with an odds ratio (OR) with 95% confidence interval (95% CI) of 2.31 (0.87-5.55) compared to having mild OSA in definite COVID-19 group. Those not undergoing treatment for OSA had an OR (95% CI) of 2.43 (1.26-4.67) for definite COVID-19 compared to those accepting treatment in definite COVID-19 group. Total sleep times (TSTs) were 354, 340, and 320 minutes in healthy, suspected, and COVID-19 groups, respectively; TST was associated with COVID-19 (P-value = .04). Similarly, sleep efficiency (SE) scores were 75.7, 74.2, and 67.9% for the healthy, suspected, and COVID-19 groups, respectively (P-value = .005); Beck Depression scores were 13.8, 13.0, and 17.7, respectively (P-value = .056).

CONCLUSIONS

OSA as a proinflammatory condition with multiple comorbidities may be a contributing factor to developing COVID-19. Greater OSA severity, no treatment for OSA, and lower TST and SE were associated with increased COVID-19 prevalence among patients with OSA.

The effects of intermittent hypoxia on human nasal mucosa

Purpose

Intermittent hypoxia (IH) is characterized by hypoxia-reoxygenation, reported to be a critical risk factor for obstructive sleep apnea (OSA). This experiment aimed to evaluate the direct effects of IH on the human nasal mucosa.

Methods

The direct effects of IH on the human nasal mucosa was evaluated by measuring the ciliary beat frequency (CBF) and expression levels of inflammatory cytokines (granulocyte-macrophage colony-stimulating factor, transforming growth factor-β, interleukin-6, and tumor necrosis factor-α). The normoxia group was exposed to a normoxic condition for 72 h. The IH group was exposed to 288 cycles of IH (1 cycle: hypoxia, 5 min; subsequent normoxia, 10 min) for 72 h. CBF was measured using an automated computer-based video image processing technique. Changes in the expression of cytokines were assessed by real-time reverse transcription-polymerase chain reaction (RT-PCR).

Results

The normoxia group revealed a persistent CBF pattern and a physiological range of inflammatory cytokines. However, the IH group showed a cyclic decrease in CBF and increased expression of inflammatory cytokines. Cytotoxicity assay indicated no difference in the survival rates between the two groups.

Conclusions

IH results in increased expression of inflammatory cytokines that adversely affects the mucociliary transport in the upper airway and, consequently, may result in airway inflammation.

The relationship between NLRP3 rs10159239 and Vaspin rs2236242 gene variants and obstructive sleep apnea

BACKGROUND

In obstructive sleep apnea (OSA), recurrent upper airway obstruction and apnea/hypopnea episodes result in endothelial dysfunction, which leads to the release of many proinflammatory cytokines and reactive oxygen species (ROS). ROS induces NLRP3, a protein involved in the synthesis of interleukin (IL)-1 and IL-18; vaspin is a serine protease inhibitor that has an important role in suppressing the activation of NLRP3 inflammasome. In this study, we aimed to investigate the effect of NLRP3 rs10159239 (rs9239) and vaspin rs2236242 (rs6242) single nucleotide polymorphisms (SNPs) on OSA development.

METHODS

This study included 220 individuals who underwent polysomnography (118 patients with OSA and 102 healthy controls). NLRP3 rs9239 and vaspin rs6242 mutation frequencies were analyzed.

RESULTS

The NLRP3 rs9239 SNP genotype analysis revealed no statistically significant differences between the OSA and control groups. In the vaspin gene analysis, the rs6242 AA genotype was significantly more frequent in the OSA group compared with the control group, while the AT genotype was more frequent in controls (P = 0.004, P = 0.02). Comparison of rs6242 allele levels showed that the A allele was significantly more frequent in OSA patients than in controls (P = 0.03). The AA genotype was significantly more frequent in patients with severe OSA than in patients with mild or moderate OSA and the control group (P = 0.001 for all). Serum vaspin levels were significantly lower in carriers of the AA genotype than those with AT and TT genotypes (P = 0.001).

CONCLUSION

The vaspin rs6242 SNP AA genotype increased susceptibility to OSA, while the AT genotype appeared to be protective. The lower plasma vaspin levels in OSA compared with the control group and in patients with the AA genotype suggest that vaspin may be a protective biomarker for OSA.

Tim-3 is a potential regulator that inhibits monocyte inflammation in response to intermittent hypoxia in children with obstructive sleep apnea syndrome

The mechanism of the characteristic intermittent hypoxia (IH) of obstructive sleep apnea syndrome (OSAS) on monocyte remain unclear. Our study found that OSAS children had a significantly upregulated expression in circulating proinflammatory cytokines IL-6 and IL-12, and endothelial injury markers VEGF and ICAM1. Association analysis revealed that the plasma TNFα, IL-1β, IL-6, IL-10 and IL-12 concentration were negatively associated with the minimal SpO₂, a negative index for disease severity. OSAS monocytes presented an inflammatory phenotype with higher mRNA levels of inflammatory cytokines. Importantly, we noted a significant decrease in T-cell immunoglobulin and mucin domain (Tim)-3 expression in OSAS monocytes with the increase of the plasma proinflammatory cytokines. In vitro assay demonstrated that IH induced THP-1 cell overactivation via NF-κB dependent pathway was inhibited by the Tim-3 signal. Our results indicated that activation of monocyte inflammatory responses is closely related to OSAS-induced IH, and negatively mediated by a Tim-3 signaling pathway.

Cognitive profiles in obstructive sleep apnea: a cluster analysis in sleep clinic and community samples

STUDY OBJECTIVES

Although cognitive dysfunction is a recognized consequence of untreated obstructive sleep apnea (OSA), the deficit pattern is heterogeneous. Understanding this heterogeneity may identify those at risk of cognitive deficits and guide intervention strategies. To facilitate understanding, we examined whether distinct profiles of neuropsychological performance were present in OSA and, if so, how they are related to other OSA features.

METHODS

We studied sleep clinic (n = 121) and community (n = 398) samples with moderate-severe OSA (apnea-hypopnea index ≥ 15 events/h). Attention and memory were assessed using the Cognitive Drug Research system. Sleep was assessed using polysomnography in the clinic sample and dual channel (flow, oximetry) portable monitoring in the community sample. Latent profile analysis was used to determine structure of cognitive clusters. Discriminant function analysis was used to examine associations between nocturnal and diurnal features of OSA and profile membership.

RESULTS

Both samples were best characterized by a 3-profile solution: (1) strong thinkers (performed well across most domains and showed greater cognitive reserve); (2) inattentive fast thinkers (strong processing speed but poor ability to maintain attention); and (3) accurate slow thinkers (strengths in maintaining attention but poor processing speed). Profile membership was associated with mean overnight oxygen saturation and cognitive reserve in the clinic sample and the presence of cardiovascular disease and/or diabetes in the community sample.

CONCLUSIONS

These findings help explain the diversity of outcomes in previous studies of cognitive dysfunction in OSA by demonstrating that individual differences in cognitive reserve, nocturnal oxygen saturation, and comorbidities affect how cognition is impacted by OSA.

Effect of Sleep Disorders on Blood Pressure and Hypertension in Children

PURPOSE OF REVIEW

In this review, we aim to discuss the pathophysiologic basis of hypertension in sleep disorders and the current evidence in the medical literature linking sleep disorders and hypertension in children.

RECENT FINDINGS

The medical literature in adults is clear about the contribution of sleep disorders, poor sleep quality, and sleep deprivation to hypertension and increased cardiovascular risk. The literature on cardiovascular consequences of sleep disorders in children is not as robust, but there is some evidence of early cardiovascular changes in children with sleep deprivation and obstructive sleep apnea. Children with obstructive sleep apnea have increased sympathetic activation during sleep, blunted dipping, or elevated systolic or diastolic pressures. Although the literature on other sleep disorders such as narcolepsy and restless legs syndrome is scarce, there is evidence in adults and some recent supportive data in children.

Association between tumor necrosis factor alpha and obstructive sleep apnea in adults: a meta-analysis update

BACKGROUND

Tumor necrosis factor-α (TNF-α) has been reported to play a part in the development of obstructive sleep apnea (OSA) and its complications. However, the relationship between TNF-α and OSA still remains inconclusive. We aimed to systematically review and synthesize studies published to date on association between the two in adults.

METHODS

We searched for English-language articles containing original human data from case-control study studies in adults≥18 years of age. The selection criteria were set according to the PICOS framework. Articles were independently reviewed by three investigators. Data regarding demographics, clinical characteristics, and TNF-α levels were obtained. A random-effects model was applied to evaluate the overall effect sizes by calculating standard mean difference (SMD) and its 95% confidence intervals (CIs).

RESULTS

Of 393 identified abstracts, 50 articles (3503 OSA patients and 3379 health controls) were ultimately included in this meta-analysis. The results indicated that the TNF-α level in patients with OSA was 1.77 (95%CI, 1.37 to 2.17, I² = 97.8%, P < 0.0001) times higher than in the control group. Subgroup analyses showed a positive correlation between the level of TNF-α and OSA severity. According to meta-regression, we noted that aging significantly predicted an increased effect size of TNF-α level in OSA patients (P < 0.007).

CONCLUSION

This study identified a significant association between OSA and elevated TNF-α level in adults. Meanwhile, TNF-α levels were consistently correlated with severity of OSA, which indicated it might be a promising biomarker for the development of OSA. However, well-designed, large-scale, case-control cohorts are needed to better understand the relationship of TNF-α in the context of adult OSA.

Evaluation of preoperative and postoperative serum interleukin-6, interleukin-8, tumor necrosis factor α and raftlin levels in patients with obstructive sleep apnea

BACKGROUND

Raftlin is a large, major lipid raft protein of cell membranes. Raftlin levels have not been previously examined in patients with obstructive sleep apnea (OSA). Our study aimed to evaluate the changes in raftlin, interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor alpha (TNFα) values from the preoperative state to the third month postoperatively in patients undergoing expansion sphincter pharyngoplasty for OSA.

METHODS

Of 60 patients, 10 patients had mild OSA (AHI 5-14), 10 moderate (AHI 15-29), 10 severe (AHI ≥ 30), and 30 with AHI < 5 formed a control group. Preoperatively and at 3 months post-operatively, IL-6, IL-8, TNFα, and raftlin values were measured.

RESULTS

Preoperatively, mean raftlin levels were 914.4 ± 62.7 pg/mL for controls, 910.0 ± 42.5 pg/mL in mild, 1000.5 ± 63.3 pg/mL in moderate, and 1386.3 ± 101.4 pg/mL in severe groups, with moderate and severe groups significantly elevated compared to controls (p < 0.001). Preoperatively to 3 months post-operatively, raftlin levels decreased significantly in each OSA group (p < 0.05). Levels of IL-6, IL-8 and TNFα followed similar patterns at baseline and after surgical intervention.

CONCLUSIONS

Raftlin levels at the third postoperative month decreased significantly compared with preoperative levels in parallel with other markers of inflammation.

Evaluation of Serum and Plasma Interleukin-6 Levels in Obstructive Sleep Apnea Syndrome: A Meta-Analysis and Meta-Regression

Obstructive sleep apnea syndrome (OSAS) is considered a low-grade chronic inflammatory disease. Interleukin-6 (IL-6) is one of the most significant inflammatory markers and an excellent proxy for the inflammatory/immune system. The present meta-analysis and meta-regression aimed at comparing plasma and serum levels of IL-6 between individuals (children and adults) with OSAS and healthy controls. Four databases, PubMed/Medline, Scopus, Cochrane Library, and Web of Science, were comprehensively searched to retrieve articles published up to December, 2019, with no further restrictions. RevMan 5.3 software was used to calculate the crude mean difference (MD) and 95% confidence interval (CI). The results of funnel plots and meta-regression were analyzed by the CMA 2.0 software. Sixty-three studies (57 with adults; six with children) were included in the present meta-analysis. For adults, 37 studies reported significantly higher serum IL-6 levels and 20 reported significantly higher plasma IL-6 levels for those with OSAS than for healthy controls [pooled MD of 2.89 pg/ml (P < 0.00001) and pooled MD of 2.89 pg/ml (P < 0.00001), respectively]. The pooled analysis of serum and plasma IL-6 levels in children with OSAS compared with controls revealed that only the MD of plasma IL-6 levels was significant (MD = 0.84 pg/ml, P = 0.004). Results of the meta-regression showed that greater age was associated with higher serum IL-6 levels. Egger's test revealed a publication bias across the studies for serum and plasma IL-6 levels (P = 0.00044 and P = 0.01445, respectively). In summary, the meta-analysis and meta-regression confirmed that, compared to healthy controls, individuals with OSAS (children and adults) had higher serum/plasma IL-6 levels.

Serum and Plasma Tumor Necrosis Factor Alpha Levels in Individuals with Obstructive Sleep Apnea Syndrome: A Meta-Analysis and Meta-Regression

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) is associated with a variety of inflammatory factors. Specifically, proinflammatory cytokines appear to be associated with the pathogenesis of OSAS.

METHODS

For the present meta-analysis and meta-regression on serum and plasma tumor necrosis factor alpha (TNF-α) levels in individuals with and without OSAS, we performed a systematic search without any restrictions of the PubMed/Medline, Scopus, Cochrane Library, and Web of Science databases to find relevant articles published up to February 1, 2020.

RESULTS

Fifty-five (adults: 29 studies on serum and 17 studies on plasma; children: 4 studies on serum and 5 studies on plasma) were included and analyzed. Always compared to age-matched healthy controls, the pooled MDs were as follows: adults, serum: 10.22 pg/mL (95% CI = 8.86, 11.58; p < 0.00001); adults, plasma: 5.90 pg/mL (95% CI = 4.00, 7.80; p < 0.00001); children, serum: 0.21 pg/mL (95% CI = 0.05, 0.37; p = 0.01); children, plasma: 5.90 pg/mL (95% CI = 4.00, 7.80; p < 0.00001).

CONCLUSIONS

Compared to healthy and age-matched controls, adult individuals with OSAS had significantly higher serum/plasma TNF-α levels. For children with OSAS, significantly higher levels were observed for TNF-α in serum but not in plasma.

The relationship between diurnal variation of cytokines and symptom expression in mild obstructive sleep apnea

OBJECTIVES

To identify the relationship between (1) cytokines and everyday symptoms and (2) cytokine diurnal variation and everyday symptoms in mild obstructive sleep apnea (OSA).

METHODS

An observational, single-night study of 20 adults with mild to moderate OSA undergoing diagnostic polysomnography. Everyday symptoms included sleepiness measured by Stanford Sleepiness Scale, fatigue and energy levels measured by Lee Fatigue Scale, and cytokine plasma concentrations including interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor-α (TNF-α) measured concurrent with symptoms at presleep (8 pm to 10 pm; time 1) and postsleep (5 am to 6 am; time. 2) Cytokine diurnal variation was calculated as [time 2 - time 1]. Wilcoxon signed-rank tests and Spearman partial rank correlations adjusted for age, body mass index, cardiovascular disease, and type 2 diabetes were used.

RESULTS

Twenty patients (50% male, obese, median age = 51.0 years) with mild OSA (apnea-hypopnea index, AHI; median 9.5 events/h) were evaluated. Evening IL-6 was associated with evening symptoms, including sleepiness (r = .69, P = .002) and energy level (r = -0.68, P = .003); morning IL-8 (r = .73, P = .001), and TNF-α (r = .59, P = .015) were associated with morning fatigue. Only morning IL-8 (r = -0.57, P = .022) and diurnal variations in IL-8 (r = -0.60, P = .014) were associated with morning energy level.

CONCLUSION

There is scant evidence addressing the diurnal variation of inflammatory biomarkers and the relationship with symptom expression in mild OSA. The present findings provide preliminary mechanistic findings for symptom expression in OSA and contribute insight to mild OSA symptom phenotypes.

Alterations in Serum Adropin, Adiponectin, and Proinflammatory Cytokine Levels in OSAS

Objective

The present study was planned to examine the relationships between obstructive sleep apnea syndrome (OSAS) and the newly revealed adipokines adropin and adiponectin concentrations that display significant metabolic and cardiovascular functions and the levels of proinflammatory cytokine levels.

Method

A total of 166 overweight and obese male patients with a body mass index (BMI) >27 kg/m² were included in the study. Among study participants, 84 were recently diagnosed with OSAS by polysomnography with an apnea-hypopnea index (AHI) ≥5, and 82 were nonapneic with normal polysomnography (AHI<5) findings. The serum adropin and adiponectin levels of all cases were analyzed via the enzyme-linked immunosorbent assay method. Serum interleukin-1 (IL-1) beta and tumor necrotizing factor-alpha (TNF-alpha) levels were determined using Luminex cytokine multiplex analyses.

Results

The mean age of the OSAS patients was 50.9 ± 5.7 years and BMI was 32.4 ± 6.0 kg/m², and there was no statistically significant difference determined with the control group (49.3 ± 5.8 years and 30.6 ± 5, 6 kg/m²) (p > 0.05). There were no statistically significant differences between the OSAS and control groups concerning total cholesterol, triglyceride, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and glucose levels. Adiponectin was lower in the OSAS group at a statistically significant level in comparison with the control group and was related at a statistically significant level to OSAS intensity. Adropin concentration was determined to be higher in the OSAS group at a statistically significant level in comparison with the control group.

Conclusion

The results of our study suggest that increased adropin concentration may be an indicator of endothelium dysfunction in OSAS patients. Serum adropin and adiponectin levels may be new bioindicators used for diagnosis and risk assessment in OSAS patients.

Does ischemia-modified albumin level predict severity of obstructive sleep apnea?

OBJECTIVE AND AIM

Ischemia-modified albumin (IMA) is a newly recognized marker of chronic inflammation used to evaluate oxidative stress status in patients with various diseases. We explored the possible relationship between IMA levels and obstructive sleep apnea (OSA).

METHODS

In this retrospective study, 169 of 216 sequential patients being evaluated for suspicion of OSAS met inclusion criteria. Polysomnography confirmed OSA in 86 patients (51%) while 81 patients (49%) without OSA were categorized as control subjects. All study participants were tested for blood IMA level, neutrophil/lymphocyte ratio (NLR), C-reactive protein (CRP) level, and red blood cell distribution width (RDW).

RESULTS

The serum IMA level was significantly higher in patients with OSAS than controls (p = 0.008). The serum IMA level increased significantly as OSAS severity increased (r = 0.50, p < 0.001) and was positively correlated with the AHI (r = 0.41, p < 0.001), CRP level (r = 0.31, p = 0.004), body mass index (r = 0.24, p = 0.022), RDW (r = 0.31, p = 0.03), oxygen desaturation index (ODI) (r = 0.22, p = 0.02), and negatively correlated with the hemoglobin concentration (r = - 0.28, p = 0.04) and minimum hemoglobin oxygen saturation (SpO2) (r = - 0.25, p = 0.02). Receiver operator curve (ROC) analysis showed that the optimal serum IMA, CRP, RDW, and NLR values were not different for predicting OSAS diagnosis (areas under the curves (AUC) = 0.62, 0.59, 0.60, and 0.43, respectively). However, the serum IMA level was superior in reflecting OSAS severity (AUC = 0.78) compared to CRP, RDW, and NLR values (AUC = 0.61, 0.53, and 0.51, respectively) (all p < 0.001).

CONCLUSION

Like other markers of inflammation, blood IMA levels were significantly elevated in patients with OSA. However, blood IMA level was a better predictor of disease severity than the other markers.

Magnitude of Nonalcoholic Fatty Liver Disease: Western Perspective

The incidence of nonalcoholic fatty liver disease (NAFLD) is continuing to rise worldwide, and it is estimated that this disquieting trend will continue for another 10-15 years before prevalence begins to decrease. NAFLD is the hepatic manifestation of metabolic syndrome. As obesity, diabetes, and other lifestyle-related diseases continue to rise, the spectrum of NAFLD, e.g., nonalcoholic steatohepatitis, liver fibrosis, liver cirrhosis, liver-related morbidity, and mortality, will increase in parallel. Its widespread prevalence and associated economic burden have drawn significant attention, and a multitude of pharmaceutical companies are participating in active research trying to find a "cure". Unfortunately, as of now, no targeted treatment exists to treat this condition, and therefore, emphasis has been on its prevention. The current review focuses on the epidemiology, clinical characteristics, risk factors, and clinical outcomes of NAFLD in Western countries. It is important to understand the magnitude of NAFLD and its risk factors in Western countries where the prevalence of NAFLD has now reached epidemic proportions to identify the best strategy to prevent and possibly control this epidemic.

Intermittent Hypoxia Up-Regulates CCL2, RETN, and TNFα mRNAs in Adipocytes via Down-regulation of miR-452

Sleep apnea syndrome (SAS), characterized by recurrent episodes of oxygen desaturation and reoxygenation (intermittent hypoxia [IH]), is a risk factor for insulin resistance. Recently, IH is considered to independently cause adipose tissue inflammation/dysfunction, leading to worsening insulin resistance; however, the detailed mechanism remains unknown. We exposed mouse 3T3-L1 and human SW872 adipocytes to experimental IH or normoxia for 24 h, and analyzed mRNA expression of several adipokines. We found that the mRNA levels of RETN, TNFα, and CCL2 in SW872 and 3T3-L1 adipocytes were significantly increased by IH, whereas the promoter activities of these genes were not increased. A target mRNA search of microRNA (miR)s revealed that all human mRNAs have a potential target sequence for miR-452. The miR-452 level of IH-treated cells was significantly decreased compared to normoxia-treated cells. MiR-452 mimic and non-specific control RNA (miR-452 mimic NC) were introduced into SW872 cells, and the IH-induced up-regulation of the genes was abolished by introduction of the miR-452 mimic but not by the miR-452 mimic NC. These results indicate that IH stress down-regulates the miR-452 in adipocytes, resulting in increased levels of RETN, TNFα, and CCL2 mRNAs, leading to insulin resistance in SAS patients.

Adiponectin Relieves Human Adult Cardiac Myocytes Injury Induced by Intermittent Hypoxia

Background

Obstructive sleep apnea (OSA) is associated with many cardiovascular disorders. Intermittent hypoxia (IH) is a key pathological hallmark of OSA. This study was conducted to evaluate the potential therapeutic effects and the associated mechanisms of adiponectin (APN) on IH induced human adult cardiac myocytes (HACMs) injury.

Material/Methods

HACMs were exposed to normoxia or IH (1% to 21% O₂) using a novel cell culture bio-reactor with gas-permeable membranes. Cell viability was detected by Cell Counting Kit-8 assay. Cell membrane integrity was assessed by the detection of lactate dehydrogenase (LDH) release. Cell apoptosis was analyzed by flow cytometry. Malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) levels were determined using specific assay kits. P-AMPK (AMP-activated protein kinase), p-LKB1, and p-p65 protein levels were measured by western blotting. Pro-inflammatory factors including interleukin (IL)-1β, IL-6, IL-8 expressions were detected by enzyme-linked immunosorbent assay and quantitative real-time polymerase chain reaction.

Results

The results showed that APN had no cytotoxic to HACMs. Compared with the control group, HACMs cell viability significantly decreased, LDH release increased and cell apoptosis increased in the IH group. The levels of IL-1β, IL-6, IL-8, MDA, and p-p65 were higher, while the levels of SOD, GSH-Px, p-AMPK, and p-LKB1 were lower in HACMs cells in the IH group than that in the control group. However, APN treatment significantly rescued these effects compared with the IH group in a dose-dependent manner.

Conclusions

In conclusion, these results indicated that APN protected against IH induced HACMs injury possibly mediated by AMPK and NF-κB pathway.

Obstructive Sleep Apnea and Inflammation: Proof of Concept Based on Two Illustrative Cytokines

Obstructive sleep apnea syndrome (OSAS) is a markedly prevalent condition across the lifespan, particularly in overweight and obese individuals, which has been associated with an independent risk for neurocognitive, behavioral, and mood problems as well as cardiovascular and metabolic morbidities, ultimately fostering increases in overall mortality rates. In adult patients, excessive daytime sleepiness (EDS) is the most frequent symptom leading to clinical referral for evaluation and treatment, but classic EDS features are less likely to be reported in children, particularly among those with normal body-mass index. The cumulative evidence collected over the last two decades supports a conceptual framework, whereby sleep-disordered breathing in general and more particularly OSAS should be viewed as low-grade chronic inflammatory diseases. Accordingly, it is assumed that a proportion of the morbid phenotypic signature in OSAS is causally explained by underlying inflammatory processes inducing end-organ dysfunction. Here, the published links between OSAS and systemic inflammation will be critically reviewed, with special focus on the pro-inflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6), since these constitute classical prototypes of the large spectrum of inflammatory molecules that have been explored in OSAS patients.

[Transvenous neurostimulation in central sleep apnea associated with heart failure]

Sleep-related breathing disorders can be classified as either obstructive (OSA) or central sleep apnea (CSA). Whereas there is substantial knowledge about the pathophysiology and sound recommendations for the diagnosis and treatment of OSA, the origin of CSA is still incompletely understood, patient identification is difficult and the necessity for specific treatment is under debate. CSA often accompanies heart failure and is associated with an adverse prognosis. Optimized heart failure treatment reduces CSA and is thus the cornerstone of CSA treatment. In contrast to OSA, noninvasive ventilation does not lead to prognostic improvement in CSA and ASV ventilation may even lead to an increase in mortality. Transvenous neurostimuation of the phrenic nerve is currently under clinical investigation as a new therapeutic modality for CSA. Early results demonstrate positive effects on sleep parameters and quality of life without any evidence for a negative impact on mortality. However, these results await confirmation in larger studies before this new approach can be advocated for routine clinical use.

Confounders of severe asthma: diagnoses to consider when asthma symptoms persist despite optimal therapy

Asthma can often be challenging to diagnose especially when patients present with atypical symptoms. Therefore, it is important to have a broad differential diagnosis for asthma to ensure that other conditions are not missed. Clinicians must maintain a high index of suspicion for asthma mimickers, especially when patients fail to respond to conventional therapy. The purpose of this review is to briefly review some of the more common causes of asthma mimickers that clinicians should consider when the diagnosis of asthma is unclear.

Clinical and experimental aspects of breathing modulation by inflammation

Neuroinflammation is produced by local or systemic alterations and mediated mainly by glia, affecting the activity of various neural circuits including those involved in breathing rhythm generation and control. Several pathological conditions, such as sudden infant death syndrome, obstructive sleep apnea and asthma exert an inflammatory influence on breathing-related circuits. Consequently breathing (both resting and ventilatory responses to physiological challenges), is affected; e.g., responses to hypoxia and hypercapnia are compromised. Moreover, inflammation can induce long-lasting changes in breathing and affect adaptive plasticity; e.g., hypoxic acclimatization or long-term facilitation. Mediators of the influences of inflammation on breathing are most likely proinflammatory molecules such as cytokines and prostaglandins. The focus of this review is to summarize the available information concerning the modulation of the breathing function by inflammation and the cellular and molecular aspects of this process. I will consider: 1) some clinical and experimental conditions in which inflammation influences breathing; 2) the variety of experimental approaches used to understand this inflammatory modulation; 3) the likely cellular and molecular mechanisms.

The effectiveness of dapagliflozin for sleep-disordered breathing among Japanese patients with obesity and type 2 diabetes mellitus

Weight reduction is important in patients with sleep-disordered breathing (SDB). In Japanese patients, slight weight reduction is effective for improving the severity of SDB. However, the effect of weight reduction after administration of sodium glucose co-transporter 2 (SGLT2) inhibitor for SDB remains unclear. The aim of this study was to evaluate the improvement of SDB from baseline after administration of dapagliflozin (5 mg) once daily for 24 weeks among Japanese patients with obesity and type 2 diabetes mellitus. Thirty Japanese patients with type 2 diabetes mellitus and SDB were enrolled in a 24-week, prospective, open-label, single-arm, multicentre trial. SDB was defined as at least five 3% oxygen desaturation index (ODI) events per hour, and moderate to severe SDB was defined as at least 15 ODI events per hour. The primary endpoint was the change in 3% ODI between before dapagliflozin administration and at 24 weeks. The prevalence of moderate to severe SDB was 20% in the present study. After administration of dapagliflozin, fasting glucose, HbA1c, aspartate aminotransferase, total cholesterol, low-density lipoprotein cholesterol, and estimated globular filtration rate decreased significantly. The improvement of 3% ODI was observed in patients with moderate to severe SDB but not mild SDB (from 25.0 ± 3.8 at baseline to 18.5 ± 6.1 at 24 weeks, p = 0.017). In conclusion, dapagliflozin might improve moderate to severe SDB but not mild SDB in Japanese patients with obesity and type 2 diabetes mellitus.