Biological plausibility linking sleep apnoea and metabolic dysfunction

State of the art: Alternative overlap syndrome-asthma and obstructive sleep apnea

In the general population, Bronchial Asthma (BA) and Obstructive Sleep Apnea (OSA) are among the most prevalent chronic respiratory disorders. Significant epidemiologic connections and complex pathogenetic pathways link these disorders via complex interactions at genetic, epigenetic, and environmental levels. The coexistence of BA and OSA in an individual likely represents a distinct syndrome, that is, a collection of clinical manifestations attributable to several mechanisms and pathobiological signatures. To avoid terminological confusion, this association has been named alternative overlap syndrome (vs overlap syndrome represented by the chronic obstructive pulmonary disease-OSA association). This comprehensive review summarizes the complex, often bidirectional links between the constituents of the alternative overlap syndrome. Cross-sectional, population, or clinic-based studies are unlikely to elucidate causality or directionality in these relationships. Even longitudinal epidemiological evaluations in BA cohorts developing over time OSA, or OSA cohorts developing BA during follow-up cannot exclude time factors or causal influence of other known or unknown mediators. As such, a lot of pathophysiological interactions described here have suggestive evidence, biological plausibility, potential or actual directionality. By showcasing existing evidence and current knowledge gaps, the hope is that deliberate, focused, and collaborative efforts in the near-future will be geared toward opportunities to shine light on the unknowns and accelerate discovery in this field of health, clinical care, education, research, and scholarly endeavors.

Therapeutic Potential of Glucagon-like Peptide-1 Receptor Agonists in Obstructive Sleep Apnea Syndrome Management: A Narrative Review

Background: Obstructive Sleep Apnea (OSA) is a prevalent disorder characterized by repetitive upper airway obstructions during sleep, leading to intermittent hypoxia and sleep fragmentation. Current treatments, particularly Continuous Positive Airway Pressure (CPAP), face adherence challenges, necessitating novel therapeutic approaches. Methods: This review explores the potential of Glucagon-like Peptide-1 receptor agonists (GLP-1RA), commonly used for type 2 diabetes and obesity, in managing OSA. GLP-1RA promotes weight loss, enhances insulin sensitivity, and exhibits anti-inflammatory and neuroprotective properties, potentially addressing key pathophysiological aspects of OSA. Results: Emerging evidence suggests that these agents may reduce OSA severity by decreasing upper airway fat deposition and improving respiratory control. Clinical trials have demonstrated significant reductions in the Apnea-Hypopnea Index (AHI) and improvements in sleep quality with GLP-1 therapy. Conclusions: Future research should focus on elucidating the mechanisms underlying GLP-1 effects on OSAS, optimizing combination therapies, and identifying patient subgroups that may benefit the most. Integrating GLP-1RA into OSAS management could revolutionize treatment by addressing both the metabolic and respiratory components of the disorder, ultimately enhancing patient outcomes.

Causal associations of obstructive sleep apnea with Chronic Respiratory Diseases: a Mendelian Randomization study

PURPOSE

This study aimed to elucidate the causal relationship between Obstructive Sleep Apnea (OSA) and Chronic Respiratory Diseases (CRDs), employing Mendelian Randomization (MR) to overcome limitations inherent in observational studies.

METHODS

Utilizing a two-sample MR approach, this study analyzed genetic variants as instrumental variables to investigate the causal link between OSA and various CRDs, including chronic obstructive pulmonary disease (COPD), asthma, bronchiectasis, and idiopathic pulmonary fibrosis (IPF). Data were sourced from the FinnGen Consortium (OSA, n = 375,657) and UK Biobank, focusing on genome-wide associations between single-nucleotide polymorphisms (SNPs) and the diseases. Instrumental variables were selected based on strict criteria, and analyses included a random-effects inverse-variance weighted method supplemented by several sensitivity analyses.

RESULTS

The study suggests a protective effect of OSA against COPD (OR = 0.819, 95% CI 0.722-0.929, P-value = 0.002), which becomes non-significant after adjusting for BMI, indicating a potential mediating role of BMI in the OSA-COPD nexus. No significant causal links were found between OSA and other CRDs (asthma, IPF, bronchiectasis) or between COPD, asthma, and OSA.

CONCLUSIONS

Our findings reveal a BMI-mediated protective effect of OSA on COPD, with no causal connections identified between OSA and other CRDs. These results emphasize the complex relationship between OSA, BMI, and COPD, guiding future clinical strategies and research directions, particularly in light of the study's genetic analysis limitations.

Assessment of the gut microbiota of children with obstructive sleep apnea syndrome: A systematic review

Sleep-disordered breathing promotes not only unfavorable craniofacial changes in untreated pediatric patients but also neurocognitive, metabolic, cardiovascular, and even long-term social alterations. This systematic review evaluated whether children diagnosed with obstructive sleep apnea syndrome (OSAS) have different intestinal microbiota constitutions from healthy children and was based on the PRISMA guidelines (PROSPERO: CRD42022360074). A total of 1562 clinical studies published between 2019 and 2023 were selected from the PubMed/MEDLINE, Embase, Web of Science, Scopus, and Cochrane Library databases, of which five were included in the qualitative analysis, three being randomized and two prospective. The methodological quality was assessed (RoB 2.0 and ROBINS-I) and all studies showed a negative effect of intervention. Sleep deprivation and intermittent hypoxia in children with OSAS seem to trigger a cascade of inflammatory pathways that exacerbate the tissue response to the release of reactive oxygen species and the generation of oxidative stress, leading to a reduction in oxygen supply to the intestinal mucosa and the integral destruction of the intestinal barrier. More evidence-based investigations are needed to optimize the identification of possible alterations in the gut microbiota of pediatric patients, given that its composition may be influenced by the patient's sleep quality and, consequently, by OSAS, showing quantitative and qualitative alterations compared to that found in healthy individuals.

Association of Obstructive Sleep Apnea with Nonalcoholic Fatty Liver Disease: Evidence, Mechanism, and Treatment

Obstructive sleep apnea (OSA), a common sleep-disordered breathing condition, is characterized by intermittent hypoxia (IH) and sleep fragmentation and has been implicated in the pathogenesis and severity of nonalcoholic fatty liver disease (NAFLD). Abnormal molecular changes mediated by IH, such as high expression of hypoxia-inducible factors, are reportedly involved in abnormal pathophysiological states, including insulin resistance, abnormal lipid metabolism, cell death, and inflammation, which mediate the development of NAFLD. However, the relationship between IH and NAFLD remains to be fully elucidated. In this review, we discuss the clinical correlation between OSA and NAFLD, focusing on the molecular mechanisms of IH in NAFLD progression. We meticulously summarize clinical studies evaluating the therapeutic efficacy of continuous positive airway pressure treatment for NAFLD in OSA. Additionally, we compile potential molecular biomarkers for the co-occurrence of OSA and NAFLD. Finally, we discuss the current research progress and challenges in the field of OSA and NAFLD and propose future directions and prospects.

Assessing causality between obstructive sleep apnea with the dyslipidemia and osteoporosis: a Mendelian randomization study

Purpose

This study aims to assess the causal relationship between Obstructive Sleep Apnea (OSA), dyslipidemia, and osteoporosis using Mendelian Randomization (MR) techniques.

Methods

Utilizing a two-sample MR approach, the study examines the causal relationship between dyslipidemia and osteoporosis. Multivariable MR analyses were used to test the independence of the causal association of dyslipidemia with OSA. Single nucleotide polymorphisms (SNPs) were selected as instrumental variables based on genome-wide significance, independence, and linkage disequilibrium criteria. The data were sourced from publicly available Genome-Wide Association Studies (GWAS) of OSA (n = 375,657) from the FinnGen Consortium, the Global Lipids Genetics Consortium of dyslipidemia (n = 188,577) and the UK Biobank for osteoporosis (n = 456,348).

Results

The MR analysis identified a significant positive association between genetically predicted OSA and triglyceride levels (OR: 1.15, 95% CI: 1.04-1.26, p = 0.006) and a negative correlation with high-density lipoprotein cholesterol (HDL-C) (OR: 0.84, 95% CI: 0.77-0.93, p = 0.0003). Conversely, no causal relationship was found between dyslipidemia (total cholesterol, triglycerides, HDL-C, and low-density lipoprotein cholesterol) and OSA or the relationship between OSA and osteoporosis.

Conclusion

The study provides evidence of a causal relationship between OSA and dyslipidemia, highlighting the need for targeted prevention and management strategies for OSA to address lipid abnormalities. The absence of a causal link with osteoporosis and in the reverse direction emphasizes the need for further research in this area.

Contribution of Obstructive Sleep Apnea to Asthmatic Airway Inflammation and Impact of Its Treatment on the Course of Asthma

Asthma and obstructive sleep apnea (OSA) are very common respiratory disorders in the general population. Beyond their high prevalence, shared risk factors, and genetic linkages, bidirectional relationships between asthma and OSA exist, each disorder affecting the other's presence and severity. The author reviews here some of the salient links between constituents of the alternative overlap syndrome, that is, OSA comorbid with asthma, with an emphasis on the effects of OSA or its treatment on inflammation in asthma. In the directional relationship from OSA toward asthma, beyond direct influences, multiple factors and comorbidities seem to contribute.

Melatonin Improves Glucose Homeostasis and Insulin Sensitivity by Mitigating Inflammation and Activating AMPK Signaling in a Mouse Model of Sleep Fragmentation

Sleep fragmentation (SF) can increase inflammation and production of reactive oxygen species (ROS), leading to metabolic dysfunction. SF is associated with inflammation of adipose tissue and insulin resistance. Several studies have suggested that melatonin may have beneficial metabolic effects due to activating AMP-activated protein kinase (AMPK). However, it is unclear whether melatonin affects the AMPK signaling pathway in SF-induced metabolic dysfunction. Therefore, we hypothesize that SF induces metabolic impairment and inflammation in white adipose tissue (WAT), as well as altered intracellular homeostasis. We further hypothesize that these conditions could be improved by melatonin treatment. We conducted an experiment using adult male C57BL/6 mice, which were divided into three groups: control, SF, and SF with melatonin treatment (SF+Mel). The SF mice were housed in SF chambers, while the SF+Mel mice received daily oral melatonin. After 12 weeks, glucose tolerance tests, insulin tolerance tests, adipose tissue inflammation tests, and AMPK assessments were performed. The SF mice showed increased weight gain, impaired glucose regulation, inflammation, and decreased AMPK in WAT compared to the controls. Melatonin significantly improved these outcomes by mitigating SF-induced metabolic dysfunction, inflammation, and AMPK downregulation in adipose tissue. The therapeutic efficacy of melatonin against cardiometabolic impairments in SF may be due to its ability to restore adipose tissue homeostatic pathways.

Comparing Sleep Patterns and Clinical Features between Preschool and School-Age Children with OSA

OBJECTIVE

This study aimed to evaluate sleep patterns and investigate differences in clinical features among young individuals with snoring and obstructive sleep apnea (OSA).

METHODS

Data from 213 children and adolescents who underwent polysomnography (PSG) for primary snoring or OSA were collected between July 2017 and December 2021. To analyze differences in sleep architecture, hypoxia levels, and other clinical features, the participants were divided into two age groups: a preschool group and a school-age group.

RESULTS

The school-age group had significantly higher apnea-hypopnea index, obstructive apnea index, oxygen desaturation index, and body mass index than the preschool group. Both the lowest and average oxygen saturation levels were lower in the school-age group. Adenoid hypertrophy was more prevalent in the preschool group. The rate of overweight or obesity was 35.6% in the preschool group and even 94.2% in the school-age group. There were higher percentages of N1 and N2 sleep stages, and lower percentages of N3 and REM sleep stages in the school-age group. The groups exhibiting moderate to severe OSA demonstrated significant alterations in the difference between sleeping and waking diastolic blood pressure.

CONCLUSION

There is a higher frequency of respiratory events among school-age children compared with their preschool peers. Moreover, alterations in sleep structure are more prominent in the school-age group. Adenoid hypertrophy may serve as the primary instigator of OSA in preschool children, whereas the predominant causes in school-age children may be obesity or excessive weight.

LEVEL OF EVIDENCE

Retrospective chart review, 3 Laryngoscope, 134:1472-1478, 2024.

Smart Home Sleep Respiratory Monitoring System Based on a Breath-Responsive Covalent Organic Framework

A smart home sleep respiratory monitoring system based on a breath-responsive covalent organic framework (COF) was developed and utilized to monitor the sleep respiratory behavior of real sleep apnea patients in this work. The capacitance of the interdigital electrode chip coated with COFTPDA-TFPy exhibits thousands-level reversible responses to breath humidity gases, with subsecond response time and robustness against environmental humidity. A miniaturized printed circuit board, an open-face-mask-based respiratory sensor, and a smartphone app were constructed for the wearable wireless smart home sleep respiratory monitoring system. Leveraging the sensitive and rapid reversible response of COFs, the COF-based respiratory monitoring system can effectively record normal breath, rapid breath, and breath apnea, enabling over a thousand cycles of hour-level continuous monitoring during daily wear. Next, we took the groundbreaking step of advancing the humidity sensor to the clinical trial stage. In clinical experiments on real sleep apnea patients, the COF-based respiratory monitoring system successfully recorded hour-level sleep respiratory data and differentiated the breathing behavior characteristics and severity of sleep apnea patients and subjects with normal sleep function and primary snoring patients. This work successfully advanced humidity sensors into clinical research for real patients and demonstrated the enormous application potential of COF materials in clinical diagnosis.

The role of lncRNAs in intermittent hypoxia and sleep Apnea: A review of experimental and clinical evidence

In this narrative review, we present a comprehensive assessment on the putative roles of long non-coding RNAs (lncRNAs) in intermittent hypoxia (IH) and sleep apnea. Collectively, the evidence from cell culture, animal, and clinical research studies points to the functional involvement of lncRNAs in the pathogenesis, diagnosis, and potential treatment strategies for this highly prevalent disorder. Further research is clearly warranted to uncover the mechanistic pathways and to exploit the therapeutic potential of lncRNAs, thereby improving the management and outcomes of patients suffering from sleep apnea.

Snoring might be a warning sign for metabolic syndrome in nonobese Korean women

Metabolic syndrome (MetS) is an underlying cause of various diseases and is strongly associated with mortality. In particular, it has been steadily increasing along with changes in diet and lifestyle habits. The close relationship between sleep apnea and MetS is well established. In addition, these two diseases share a common factor of obesity and have a high prevalence among obese individuals. Nevertheless, the association can vary depending on factors, such as race and sex, and research on the relatively low obesity rates among East Asians is lacking. This study aimed to investigate the association between snoring and MetS in nonobese Koreans. A total of 2478 participants (827 men and 1651 women) were enrolled in the Korean National Health and Nutrition Examination Survey from 2019 to 2020. We used the National Cholesterol Education Program Adult Treatment Panel III criteria for MetS and a snoring questionnaire. Logistic regression analysis was used to measure the association between MetS and various confounding factors according to age and sex in participants with body mass index (BMI) < 23 kg/m2. MetS was significantly higher in participants with snoring than in those without snoring (26.9% vs. 19.6%; p = 0.007). In multivariate logistic regression analysis, age (odds ratio [OR] 1.070, 95% confidence interval [CI] 1.059-1.082, p < .001), sex (OR 1.531, 95% CI 1.139-2.058, p = 0.005), and snoring (OR 1.442, 95% CI 1.050-1.979, p = 0.024) were significantly associated with MetS in patients with a BMI < 23 kg/m2. Finally, regression analysis showed that snoring was significantly associated with MetS in women with a BMI of less than 23 kg/m2, especially with younger ages (40-49 years, OR 4.449, 95% CI 1.088 to 18.197, p = 0.038). Snoring was closely associated with MetS in women aged 40-50 years with a BMI of less than 23 kg/m2 compared to other participants. However, the association was not found in women aged 60 and over. Therefore, sufficient consideration should be given to the possibility of MetS when snoring is present in nonobese middle-aged Asian women.

Inflammation biomarkers in OSA, chronic obstructive pulmonary disease, and chronic obstructive pulmonary disease/OSA overlap syndrome

STUDY OBJECTIVES

The coexistence of obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) in a single individual, also known as overlap syndrome (OVS), is associated with higher cardiovascular risk and mortality than either OSA or COPD alone. However, the underlying mechanisms remain unclear. We hypothesized that patients with OVS have elevated systemic inflammatory biomarkers relative to patients with either disease alone, which could explain greater cardiovascular risk observed in OVS.

METHODS

We included 255 participants in the study, 55 with COPD alone, 100 with OSA alone, 50 with OVS, and 50 healthy controls. All participants underwent a home sleep study, spirometry, and a blood draw for high-sensitivity C-reactive protein and total blood count analysis. In a randomly selected subset of 186 participants, inflammatory protein profiling was performed using Bio-Rad Bio-Plex Pro Human Cytokine 27-Plex Assays. Biomarker level differences across groups were identified using a mixed linear model.

RESULTS

Levels of interleukin 6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), and granulocyte colony stimulating factor (G-CSF) were higher in participants with OVS and COPD compared with healthy controls and participants with OSA. Furthermore, participants with OVS had higher circulating levels of leukocytes and neutrophils than those with COPD, OSA, and controls.

CONCLUSIONS

COPD and OVS are associated with higher systemic inflammation relative to OSA and healthy controls. This work proposes the potential utilization of interleukin 6, granulocyte colony stimulating factor, and high-sensitivity C-reactive protein as screening biomarkers for COPD in patients with OSA. Inflammatory pathways may not fully explain the higher cardiovascular risk observed in OVS, indicating the need for further investigation.

CITATION

Sanchez-Azofra A, Gu W, Masso-Silva JA, et al. Inflammation biomarkers in OSA, chronic obstructive pulmonary disease, and chronic obstructive pulmonary disease/OSA overlap syndrome. J Clin Sleep Med. 2023;19(8):1447-1456.

Solriamfetol enhances wakefulness and improves cognition and anxiety in a murine model of OSA

BACKGROUND

Obstructive sleep apnea (OSA) is a chronic condition characterized by intermittent hypoxia (IH). Excessive daytime sleepiness (EDS) is a common consequence of OSA and is associated with cognitive deficits and anxiety. Modafinil (MOD) and Solriamfetol (SOL) are potent wake-promoting agents clinically used to improve wakefulness in OSA patients with EDS.

METHODS

Male C57Bl/6J mice were exposed to either IH or room air (RA) controls during the light phase for 16 weeks. Both groups were then randomly assigned to receive once-daily intraperitoneal injections of SOL (200 mg/kg), MOD (200 mg/kg) or vehicle (VEH) for 9 days while continuing IH exposures. Sleep/wake activity was assessed during the dark (active) phase. Novel object recognition (NOR), elevated-plus maze test (EPMT), and forced swim test (FST) were performed before and after drug treatment.

RESULTS

IH exposure increased dark phase sleep percentage and reduced wake bouts lengths and induced cognitive deficits and anxiogenic effects. Both SOL and MOD treatments decreased sleep propensity under IH conditions, but only SOL promoted improvements in NOR performance (explicit memory) and reduced anxiety-like behaviors.

CONCLUSION

Chronic IH, a hallmark feature of OSA, induces EDS in young adult mice that is ameliorated by both SOL and MOD. SOL, but not MOD, significantly improves IH-induced cognitive deficits and promotes anxiolytic effects. Thus, SOL could potentially benefit OSA patients beyond EDS management.

Cognitive Impairments, Neuroinflammation and Blood-Brain Barrier Permeability in Mice Exposed to Chronic Sleep Fragmentation during the Daylight Period

Obstructive sleep apnea (OSA) is a chronic condition characterized by intermittent hypoxia (IH) and sleep fragmentation (SF). In murine models, chronic SF can impair endothelial function and induce cognitive declines. These deficits are likely mediated, at least in part, by alterations in Blood-brain barrier (BBB) integrity. Male C57Bl/6J mice were randomly assigned to SF or sleep control (SC) conditions for 4 or 9 weeks and in a subset 2 or 6 weeks of normal sleep recovery. The presence of inflammation and microglia activation were evaluated. Explicit memory function was assessed with the novel object recognition (NOR) test, while BBB permeability was determined by systemic dextran-4kDA-FITC injection and Claudin 5 expression. SF exposures resulted in decreased NOR performance and in increased inflammatory markers and microglial activation, as well as enhanced BBB permeability. Explicit memory and BBB permeability were significantly associated. BBB permeability remained elevated after 2 weeks of sleep recovery (p < 0.01) and returned to baseline values only after 6 weeks. Chronic SF exposures mimicking the fragmentation of sleep that characterizes patients with OSA elicits evidence of inflammation in brain regions and explicit memory impairments in mice. Similarly, SF is also associated with increased BBB permeability, the magnitude of which is closely associated with cognitive functional losses. Despite the normalization of sleep patterns, BBB functional recovery is a protracted process that merits further investigation.

Solriamfetol improves chronic sleep fragmentation-induced increases in sleep propensity and ameliorates explicit memory in male mice

Obstructive sleep apnea (OSA) is a highly prevalent condition characterized by episodes of partial or complete breath cessation during sleep that induces sleep fragmentation (SF). One of the frequent manifestations of OSA is the presence of excessive daytime sleepiness (EDS) associated with cognitive deficits. Solriamfetol (SOL) and modafinil (MOD) are wake-promoting agents commonly prescribed to improve wakefulness in OSA patients with EDS. This study aimed to assess the effects of SOL and MOD in a murine model of OSA characterized by periodic SF. Male C57Bl/6J mice were exposed to either control sleep (SC) or SF (mimicking OSA) during the light period (06:00 h to 18:00 h) for 4 weeks, which consistently induces sustained excessive sleepiness during the dark phase. Both groups were then randomly assigned to receive once-daily intraperitoneal injections of SOL (200 mg/kg), MOD (200 mg/kg), or vehicle for 1 week while continuing exposures to SF or SC. Sleep/wake activity and sleep propensity were assessed during the dark phase. Novel Object Recognition test, Elevated-Plus Maze Test, and Forced Swim Test were performed before and after treatment. SOL or MOD decreased sleep propensity in SF, but only SOL induced improvements in explicit memory, while MOD exhibited increased anxiety behaviors. Chronic SF, a major hallmark of OSA, induces EDS in young adult mice that is mitigated by both SOL and MOD. SOL, but not MOD, significantly improves SF-induced cognitive deficits. Increased anxiety behaviors are apparent in MOD-treated mice. Further studies aiming to elucidate the beneficial cognitive effects of SOL are warranted.

Dyslipidemia prevalence in nonobese, nondiabetic patients with obstructive sleep apnea: does sex matter?

STUDY OBJECTIVES

Dyslipidemia in obstructive sleep apnea (OSA) has been attributed to confounding obesity and/or diabetes. This study aimed to examine lipid profiles in nondiabetic, nonobese patients with OSA and identify the possible effects of age and sex.

METHODS

We retrospectively evaluated the lipid parameters of 3,050 adults who underwent polysomnography. A total of 2,168 patients were excluded due to obesity (body mass index ≥ 30 kg/m2), diabetes, alcoholism, untreated hypothyroidism, lipid-lowering drug use, missing sleep data, or treatment for suspected OSA.

RESULTS

Of 882 patients (75% males, aged 46.8 ± 12.2 years) included in the study, 88.4% had OSA. Levels of total cholesterol (P = .003), low-density-lipoprotein (LDL) cholesterol (P = .005), non-high-density-lipoprotein (non-HDL) cholesterol (P = .001), and triglycerides (P = .007) were significantly higher in patients with OSA than in those without, whereas HDL-cholesterol levels did not differ. The proportion of patients with hypercholesterolemia and/or elevated non-HDL cholesterol (>  160 mg/dL) was significantly higher in OSA than in non-OSA. Correlation analyses by sex revealed stronger and more significant relationships between lipid parameters and apnea-hypopnea index in women than in men (r = .135, P < .001, vs r = .080, P = .043 for total cholesterol; r = .111, P < .001, vs r = .080, P = .046 for non-HDL cholesterol; r = .122, P < .001, vs r = .061, P = .107 for LDL cholesterol, respectively). In regression analysis, the rate of hypercholesterolemia increased with age (P < .001 for women and P = .031 for men); non-HDL- and LDL-cholesterol levels significantly increased with OSA severity (P = .035 and P = .023, respectively) and age (P = .004 and P = .001, respectively) in women.

CONCLUSIONS

After excluding confounding obesity and diabetes, patients with OSA have an impaired lipid profile including total cholesterol, LDL cholesterol, non-HDL cholesterol, and triglycerides. A significant association between dyslipidemia and OSA severity was observed in women but not in men.

CITATION

Basoglu OK, Tasbakan MS, Kayikcioglu M. Dyslipidemia prevalence in nonobese, nondiabetic patients with obstructive sleep apnea: does sex matter? J Clin Sleep Med. 2023;19(5):889-898.

SMAD4 Expression in Monocytes as a Potential Biomarker for Atherosclerosis Risk in Patients with Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) patients are at special risk of suffering atherosclerosis, leading to major cardiovascular diseases. Notably, the transforming growth factor (TGF-β) plays a crucial role in the development and progression of atherosclerosis. In this context, the central regulator of TGF-β pathway, SMAD4 (small mother against decapentaplegic homolog 4), has been previously reported to be augmented in OSA patients, which levels were even higher in patients with concomitant cardiometabolic diseases. Here, we analyzed soluble and intracellular SMAD4 levels in plasma and monocytes from OSA patients and non-apneic subjects, with or without early subclinical atherosclerosis (eSA). In addition, we used in vitro and ex vivo models to explore the mechanisms underlying SMAD4 upregulation and release. Our study confirmed elevated sSMAD4 levels in OSA patients and identified that its levels were even higher in those OSA patients with eSA. Moreover, we demonstrated that SMAD4 is overexpressed in OSA monocytes and that intermittent hypoxia contributes to SMAD4 upregulation and release in a process mediated by NLRP3. In conclusion, this study highlights the potential role of sSMAD4 as a biomarker for atherosclerosis risk in OSA patients and provides new insights into the mechanisms underlying its upregulation and release to the extracellular space.

Association between glycolipids and risk of obstructive sleep apnea: A population-based study

Background

This study aimed to investigate the associations between multiple glycolipid biomarkers and the risk of obstructive sleep apnea (OSA).

Methods

Participants (10,286) aged from 35 to 74 years old were included in this cross-sectional study from the baseline survey of the Guangzhou Heart Study. OSA was ascertained using both Berlin Questionnaire and STOP-BANG Questionnaire. Fasting blood samples were collected from each participant; fasting blood glucose (FBG) and serum concentrations of high-density lipoprotein cholesterol (HDL-CH), low-density lipoprotein cholesterol (LDL-CH), total cholesterol (TC), and triglyceride (TG) were determined. Odds ratio (OR) with 95% confidence interval (CI) was calculated using the multivariate logistic regression model after adjustment for covariates.

Results

Of the participants included, 15.56% were categorized into the pre-OSA group, and 8.22% into the OSA group. When comparing the highest with the lowest quartiles, HDL-HC was associated with a 22% (OR: 0.78, 95% CI: 0.65–0.94) and 41% (OR: 0.59, 95% CI: 0.45–0.78) reduced risk of pre-OSA and OSA, triglyceride was associated with a 32% (OR 1.32, 95% CI 1.08–1.60) and a 56% (OR 1.56, 95% CI 1.18–2.07) increased risk of pre-OSA and OSA, and FBG was associated with a 1.37-fold (95% CI 1.13–1.67) risk of pre-OSA and 1.38-fold (95% CI 1.03–1.85) risk of OSA. A significant exposure-response trend was observed for HDL-HC, TG, and FBG with both OSA and Pre-OSA (all p &lt; 0.05). No significant association of LDL-CH and TC with the risk of both pre-OSA and OSA was observed.

Conclusion

The findings suggest that serum HDL-CH was inversely associated with OSA risk, while elevated serum TG and FBG could increase the risk of OSA. Healthy glycolipid metabolism warrants more attention in the field of OSA prevention.

Effects of heated humidification on positive airway pressure side effects in patients with obstructive sleep apnoea: a meta-analysis

PURPOSE

An earlier study found that heated humidification reduced the side effects of positive airway pressure (PAP) in patients with obstructive sleep apnoea (OSA). However, other studies disagreed with this finding. Therefore, we evaluated the relationship between heated humidification and the side effects of PAP in patients with OSA.

METHODS

According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, six databases were searched for relevant randomised controlled trials (RCTs) performed from January 1999 to June 2021.

RESULTS

From 1012 retrieved articles, we identified 9 eligible RCTs. Compared to the control group, the heated humidification group reported improvements in dry nose (pooled standardised mean difference [SMD] =  - 0.70, 95% confidence interval [CI] =  - 0.96 to - 0.45, I² = 0%, p < 0.00001), blocked nose (SMD =  - 0.47, 95%CI - 0.69 to - 0.25, I² = 36%, p < 0.0001), runny nose (SMD =  - 0.22, 95%CI - 0.44 to 0, I² = 0%, p = 0.05), dry mouth (SMD =  - 0.62, 95%CI - 0.87 to - 0.37, I² = 0%, p < 0.00001), and dry throat (SMD =  - 0.61, 95%CI - 0.90 to - 0.33, I² = 41%, p < 0.0001), but did not enhance positive airway pressure adherence (pooled mean difference [MD] = 0.24, 95% CI - 0.10 to 0.58, I² = 0%, p = 0.17).

CONCLUSIONS

Heated humidification improved some PAP side effects in patients with OSA but did not increase PAP adherence. Additional large-scale multi-centre RCTs are needed to verify the long-term effects.

Can biomarkers predict the risk of cardiovascular disease in patients with obstructive sleep apnea syndrome?

Background/Aim: Obstructive sleep apnea syndrome (OSAS) is a clinical syndrome characterized by recurrent partial or total obstruction of the upper airway. Cardiovascular disease (CVD) is more common in OSAS patients. Biomarkers can predict the progression of OSAS disease and the occurrence of CVD. Here we investigate the effects of age, gender, body mass index (BMI), comorbidities, neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), platelet-to-lymphocyte ratio (PLR), systemic inflammatory index (SII), atherogenic index of plasma (AIP), C-reactive protein-to-albumin ratio (CAR) and monocyte to HDL cholesterol (MHR) on the severity of OSAS and the occurrence of CVD in OSAS patients. Method: This cross-sectional study included 172 OSAS patients presenting to Erzincan Binali Yildirim University Mengucek Gazi Training and Research Hospital, Sleep Service between 01.01.2021 and 31.08.2022. Polysomnography (PSG) was applied to patients participating in the study, and routine complete blood and biochemistry tests were performed. Comorbidities and demographic data of the participants were recorded. Results: The frequency of CVD, chronic pulmonary disease (CPD) and hyperlipidemia increased as the severity of OSAS increased (P=0.005, P<0.001, P=0.016, respectively). As the severity of OSAS disease increased, only the MHR indices increased (P=0.009). When OSAS groups with and without CVD were examined, OSAS patients with CVD were older and had higher BMI (P<0.001, P=0.001, respectively). In addition, tended to be females with hyperlipidemia, diabetes mellitus (DM) and high Charlson Comorbidity Index (CCI) scores (all P<0.001). When the polysomnography of OSAS patients with CVD was evaluated, apnea-hypopnea index (AHI), non-rapid eye movement (NREM)-AHI (NREM-AHI), respiratory disorder index (RDI) and oxygen desaturation index (ODI) values were higher and sleep efficiency (SE) values were lower than patients with OSAS without CVD (P=0.002, P=0.002, P=0.003, P<0.001, P<0.001, respectively). Conclusion: CVD is common in OSAS patients. As the severity of OSAS increases, the risk of developing CVD increases. Elderly female OSAS patients with hyperlipidemic, DM, high BMI, and Charlson Comorbidity Index (CCI) constitute a relatively risky group for CVD. OSAS patients with high AHI, NREM-AHI, RDI, ODI, and low SE values should be monitored more closely for CVD.

Nighttime sleep duration and variability in children with obstructive sleep apnea syndrome: Sociodemographic disparities and neurobehavioral outcomes

OBJECTIVES

This study examined differences in sleep patterns by race, ethnicity, and socioeconomic status (SES) among children with Obstructive Sleep Apnea Syndrome (OSAS), and linkages between sleep patterns and neurobehavioral functioning.

METHOD

We used baseline data from the Childhood Adenotonsillectomy Study (CHAT), a multicenter, single-blind, randomized controlled trial designed to evaluate the efficacy of early adenotonsillectomy versus watchful waiting with supportive care for children with OSAS. Participants included children with OSAS (ages 5.0-9.9 years). SES indicators were obtained via questionnaire and geocoding (ArcGIS version 10.1). Caregivers and teachers reported on child inattention/impulsivity and executive functioning. Nighttime sleep duration and variability were measured using five-night sleep diaries.

RESULTS

Black children experienced shorter nighttime sleep duration than White children, by about 25 min, as well as greater sleep duration variability, while sleep duration was more variable in children of "other" racial and ethnic backgrounds versus White children. Of the socioeconomic correlates, only lower family income was associated with sleep duration variability. A short and more variable nighttime sleep duration were each associated with caregiver-rated child inattention and impulsivity. Greater sleep duration variability was linked to greater teacher-rated, but not caregiver-rated, executive functioning impairments.

CONCLUSIONS

Compared to White children with OSAS, Black children with OSAS experience a shorter and more variable nighttime sleep duration. Having a short and/or variable sleep duration may increase risk for neurobehavioral impairments in youth with OSAS, underscoring the potential benefits of sleep health promotion in the context of OSAS care.

Fast cycling of intermittent hypoxia in a physiomimetic 3D environment: A novel tool for the study of the parenchymal effects of sleep apnea

Background: Patients with obstructive sleep apnea (OSA) experience recurrent hypoxemic events with a frequency sometimes exceeding 60 events/h. These episodic events induce downstream transient hypoxia in the parenchymal tissue of all organs, thereby eliciting the pathological consequences of OSA. Whereas experimental models currently apply intermittent hypoxia to cells conventionally cultured in 2D plates, there is no well-characterized setting that will subject cells to well-controlled intermittent hypoxia in a 3D environment and enable the study of the effects of OSA on the cells of interest while preserving the underlying tissue environment. Aim: To design and characterize an experimental approach that exposes cells to high-frequency intermittent hypoxia mimicking OSA in 3D (hydrogels or tissue slices). Methods: Hydrogels made from lung extracellular matrix (L-ECM) or brain tissue slices (300-800-μm thickness) were placed on a well whose bottom consisted of a permeable silicone membrane. The chamber beneath the membrane was subjected to a square wave of hypoxic/normoxic air. The oxygen concentration at different depths within the hydrogel/tissue slice was measured with an oxygen microsensor. Results: 3D-seeded cells could be subjected to well-controlled and realistic intermittent hypoxia patterns mimicking 60 apneas/h when cultured in L-ECM hydrogels ≈500 μm-thick or ex-vivo in brain slices 300-500 μm-thick. Conclusion: This novel approach will facilitate the investigation of the effects of intermittent hypoxia simulating OSA in 3D-residing cells within the parenchyma of different tissues/organs.

The Role of Gut Bacteriome in Asthma, Chronic Obstructive Pulmonary Disease and Obstructive Sleep Apnoea

The human body contains a very complex and dynamic ecosystem of bacteria. The bacteriome interacts with the host bi-directionally, and changes in either factor impact the entire system. It has long been known that chronic airway diseases are associated with disturbances in the lung bacteriome. However, less is known about the role of gut bacteriome in the most common respiratory diseases. Here, we aim to summarise the evidence concerning the role of the intestinal bacteriome in the pathogenesis and disease course of bronchial asthma, chronic obstructive pulmonary disease, and obstructive sleep apnea. Furthermore, we discuss the consequences of an altered gut bacteriome on the most common comorbidities of these lung diseases. Lastly, we also reflect on the therapeutic potential of influencing the gut microbiome to improve disease outcomes.

Chronic Intermittent Hypoxia during Sleep Causes Browning of Interscapular Adipose Tissue Accompanied by Local Insulin Resistance in Mice

Obstructive sleep apnea (OSA) is a highly prevalent condition, characterized by intermittent hypoxia (IH), sleep disruption, and altered autonomic nervous system function. OSA has been independently associated with dyslipidemia, insulin resistance, and metabolic syndrome. Brown adipose tissue (BAT) has been suggested as a modulator of systemic glucose tolerance through adaptive thermogenesis. Reductions in BAT mass have been associated with obesity and metabolic syndrome. No studies have systematically characterized the effects of chronic IH on BAT. Thus, we aimed to delineate IH effects on BAT and concomitant metabolic changes. C57BL/6J 8-week-old male mice were randomly assigned to IH during sleep (alternating 90 s cycles of 6.5% F_IO₂ followed by 21% F_IO₂) or normoxia (room air, RA) for 10 weeks. Mice were subjected to glucose tolerance testing and ¹⁸F-FDG PET-MRI towards the end of the exposures followed by BAT tissues analyses for morphological and global transcriptomic changes. Animals exposed to IH were glucose intolerant despite lower total body weight and adiposity. BAT tissues in IH-exposed mice demonstrated characteristic changes associated with "browning"-smaller lipids, increased vascularity, and a trend towards higher protein levels of UCP1. Conversely, mitochondrial DNA content and protein levels of respiratory chain complex III were reduced. Pro-inflammatory macrophages were more abundant in IH-exposed BAT. Transcriptomic analysis revealed increases in fatty acid oxidation and oxidative stress pathways in IH-exposed BAT, along with a reduction in pathways related to myogenesis, hypoxia, and IL-4 anti-inflammatory response. Functionally, IH-exposed BAT demonstrated reduced absorption of glucose on PET scans and reduced phosphorylation of AKT in response to insulin. Current studies provide initial evidence for the presence of a maladaptive response of interscapular BAT in response to chronic IH mimicking OSA, resulting in a paradoxical divergence, namely, BAT browning but tissue-specific and systemic insulin resistance. We postulate that oxidative stress, mitochondrial dysfunction, and inflammation may underlie these dichotomous outcomes in BAT.

Sleep-disordered breathing, sleep apnea, and other obesity-related sleep disorders: An Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) 2022

Background

This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) provides clinicians an overview of sleep-disordered breathing, (e.g., sleep-related hypopnea, apnea), and other obesity-related sleep disorders.

Methods

The scientific support for this CPS is based upon published citations, clinical perspectives of OMA authors, and peer review by the Obesity Medicine Association leadership.

Results

Obesity contributes to sleep-disordered breathing, with the most prevalent manifestation being obstructive sleep apnea. Obesity is also associated with other sleep disorders such as insomnia, primary snoring, and restless legs syndrome. This CPS outlines the evaluation, diagnosis, and treatment of sleep apnea and other sleep disorders, as well as the clinical implications of altered circadian system.

Conclusions

This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) on "Sleep-Disordered Breathing, Sleep Apnea, and Other Obesity-Related Sleep Disorders" is one of a series of OMA CPSs designed to assist clinicians in the care of patients with the disease of obesity.

Explicit memory, anxiety and depressive like behavior in mice exposed to chronic intermittent hypoxia, sleep fragmentation, or both during the daylight period

Obstructive sleep apnea (OSA) is a chronic and highly prevalent condition characterized by chronic intermittent hypoxia (IH) and sleep fragmentation (SF), and can lead to a vast array of end-organ morbidities, particularly affecting cardiovascular, metabolic and neurobehavioral functioning. OSA can induce cognitive and behavioral and mood deficits.

Male C57Bl/6J 8-week-old mice were housed in custom-designed cages with a silent motorized mechanical sweeper traversing the cage floor at 2-min intervals (SF) during daylight for four weeks. Sleep control (SC) consisted of keeping sweeper immobile. IH consisted of cycling FiO₂ 21% 90 seconds-6.3% 90s or room air (RA; FiO₂ 21%) for sixteen weeks and combined SF-IH was conducted for nine weeks. Open field novel object recognition (NOR) testing, elevated-plus maze test (EPMT), and forced swimming test (FST) were performed.

SF induced cognitive NOR performance impairments in mice along with reduced anxiety behaviors while IH induced deficits in NOR performance, but increased anxiety behaviors. SF-IH induced impaired performance in NOR test of similar magnitude to IH or SF alone. Combined SF-IH exposures did not affect anxiety behaviors.

Thus, both SF an IH altered cognitive function while imposing opposite effects on anxiety behaviors. SF-IH did not magnify the detrimental effects of isolated SF or IH and canceled out the effects on anxiety. Based on these findings, the underlying pathophysiologic processes underlying IH and SF adverse effects on cognitive function appear to differ, while those affecting anxiety counteract each other.

Obstructive Sleep Apnoea and Lipid Metabolism: The Summary of Evidence and Future Perspectives in the Pathophysiology of OSA-Associated Dyslipidaemia

Obstructive sleep apnoea (OSA) is associated with cardiovascular and metabolic comorbidities, including hypertension, dyslipidaemia, insulin resistance and atherosclerosis. Strong evidence suggests that OSA is associated with an altered lipid profile including elevated levels of triglyceride-rich lipoproteins and decreased levels of high-density lipoprotein (HDL). Intermittent hypoxia; sleep fragmentation; and consequential surges in the sympathetic activity, enhanced oxidative stress and systemic inflammation are the postulated mechanisms leading to metabolic alterations in OSA. Although the exact mechanisms of OSA-associated dyslipidaemia have not been fully elucidated, three main points have been found to be impaired: activated lipolysis in the adipose tissue, decreased lipid clearance from the circulation and accelerated de novo lipid synthesis. This is further complicated by the oxidisation of atherogenic lipoproteins, adipose tissue dysfunction, hormonal changes, and the reduced function of HDL particles in OSA. In this comprehensive review, we summarise and critically evaluate the current evidence about the possible mechanisms involved in OSA-associated dyslipidaemia.

Potential regulatory role of miRNA and mRNA link to metabolism affected by chronic intermittent hypoxia

Aim: Intermittent hypoxia (IH) is the prominent feature of obstructive sleep apnea (OSA) pathophysiology, which is an in dependent risk factor of cardiovascular complications. The effects of IH on adipocyte metabolism were explored by high-throughput sequencing technology.

Methods: Plasma was collected from OSA patients and control group to perform mRNA sequencing. 3T3-L1 cells were differentiated into adipocytes then subjected to a 5%–21% O₂ hypoxic environment (IH) for 24 h. High-throughput sequencing method was used to determine differential mRNA and miRNA patterns in fat cells exposed to IH. We then performed Gene Ontology (GO) analysis, identified relevant KEGG pathways and miRNA-target-pathways.

Results: Sequencing data showed that OSA affected the expression of 343 mRNAs in the plasma. At the same time, we found that IH affected the expression of 3034 mRNAs in the adipocytes. In addition, 68 differentially expressed mRNAs were overlapped in plasma from OSA patient and IH-induced adipocyte model. We observe that 68 differential genes could be connected to 49 reciprocally expressed miRNAs. We showed that IH significantly reduced the expression of miR-182-5p and miR-30c-2-3p. KEGG predicted that the function of expressed miR-182-5p and miR-30c-2-3p was enriched to AKT signaling pathway. Notably, IH activated PI3K/AKT pathway in fat cells.

Conclusion: Our results demonstrated that IH might induce adipocyte metabolism by regulating miR-182-5p and miR-30c-2-3p.

Metabolic, behavioral health, and disordered eating comorbidities associated with obesity in pediatric patients: An Obesity Medical Association (OMA) Clinical Practice Statement 2022

Background

This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) details metabolic, behavioral health, and disordered eating comorbidities associated with obesity in children. This CPS will be followed by a companion CPS covering further comorbidities, including genetics and social consequences related to overweight and obesity. These CPSs are intended to provide clinicians with an overview of clinical practices applicable to children and adolescents with body mass indices greater than or equal to the 95th percentile for their ages, particularly those with adverse consequences resulting from increased body mass. The information in this CPS is based on scientific evidence, supported by the medical literature, and derived from the clinical experiences of members of the OMA.

Methods

The scientific information and clinical guidance in this CPS is based upon referenced evidence and derived from the clinical perspectives of the authors.

Results

This OMA statement details metabolic, behavioral health, and disordered eating comorbidities associated with obesity in children. It provides clinical information regarding identifying and treating metabolic, behavioral health, and disordered eating comorbidities associated with obesity in children over the 95th percentile of weight/height for age.

Conclusions

This OMA clinical practice statement details metabolic, behavioral health, and disordered eating comorbidities associated with obesity in children and provides an overview of current recommendations. These recommendations lay out a roadmap to the improvement of the health of children and adolescents with obesity, especially those with metabolic, physiological, and psychological complications.

Intermittent hypoxia-induced METTL3 downregulation facilitates MGLL-mediated lipolysis of adipocytes in OSAS

Intermittent hypoxia (IH) is the core pathological feature of obstructive sleep apnea syndrome (OSAS), and insulin resistance (IR) is the most common metabolic complication of OSAS. Studies have shown that the levels of free fatty acids (FFAs), which are mainly released from adipocytes by lipolysis, are elevated in OSAS and play an important role in the development of IR. However, whether and how IH regulates adipocyte lipolysis in OSAS is not clear. Here, we revealed that the apnea hypopnea index was positively correlated with the serum levels of FFAs and FFA release from adipocytes in OSAS. In addition, IH facilitated lipolysis and FFA release from adipocytes by downregulating the level of METTL3. METTL3 downregulation impaired N6-methyladenosine (m6A) levels in MGLL mRNA and reduced MGLL expression, thereby promoting lipolysis. In addition, we identified YTHDF2 as the m6A reader that interacts with MGLL mRNA, accelerating its degradation. Furthermore, our data showed reduced levels of METTL3 and elevated levels of MGLL in the adipose tissues of OSAS patients and indicated an effect of METTL3 on lowering FFA levels and improving IR in rats with chronic IH. In conclusion, our study provides new insights into the development and treatment of IR in OSAS.

Inflammasome Activation: A Keystone of Proinflammatory Response in Obstructive Sleep Apnea

RATIONALE

As the mechanism that links obstructive sleep apnea (OSA) with the regulation of inflammatory response is not well known, it is important to understand the inflammasome activation, mainly of nucleotide-binding oligomerization domain-like receptor 3 (NLRP3).

OBJECTIVES

To assess the NLRP3 activity in severe OSA patients and to identify its role in the systemic inflammatory response of OSA patients.

METHODS

We analyzed the NLRP3 activity as well as key components of the inflammasome cascade, such as adaptor molecule apoptosis-associated speck-like protein (ASC), caspase-1, Gasdermin D (GSDMD), interleukin (IL)-1β, IL-18 and tissue factor (TF), in monocytes and plasma from patients with severe OSA and non-apneic healthy subjects. We explored the association of the different key markers with inflammatory comorbidities.

MAIN RESULTS

Monocytes from patients with severe OSA presented higher NLRP3 activity than those from non-apneic control subjects, which directly correlated with the apnea-hypopnea index and hypoxemic indices. NLRP3 over-activity triggered inflammatory cytokines (Il-1β and IL-18) via caspase-1 and increased Gasdermin D, allowing for tissue factor to be released. In vitro models confirmed that monocytes increase NLRP3 signaling under intermittent hypoxia (IH) in an HIF-1α-dependent manner, and/or in combination with plasma from OSA patients. Plasma levels of TF were higher in OSA patients with systemic inflammatory comorbidities than in those without them.

CONCLUSIONS

In severe OSA patients, NLRP3 activation might be a linking mechanism between intermittent hypoxia and other OSA-induced immediate changes with the development of systemic inflammatory response.

Obesity definition, diagnosis, bias, standard operating procedures (SOPs), and telehealth: An Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) 2022

Background

The Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) regarding definition, diagnosis, bias, standard operating procedures (SOPs) and telehealth is intended to provide clinicians an overview of obesity medicine and provide basic organizational tools towards establishing, directing, managing, and maintaining an obesity medical practice.

Methods

This CPS is based upon published scientific citations, clinical perspectives of OMA authors, and peer review by Obesity Medicine Association leadership.

Results

OMA has defined obesity as: "A chronic, progressive, relapsing, and treatable multi-factorial, neurobehavioral disease, wherein an increase in body fat promotes adipose tissue dysfunction and abnormal fat mass physical forces, resulting in adverse metabolic, biomechanical, and psychosocial health consequences." While body mass index may be sufficiently diagnostic for populations and many patients, accurate diagnosis of adiposity in an individual may require anthropometric assessments beyond body weight alone (e.g., waist circumference, percent body fat, and android/visceral fat). Obesity complications can be categorized as "sick fat disease" (adiposopathy) and/or "fat mass disease." Obesity complications predominantly of fat mass origins include sleep apnea and orthopedic conditions. Obesity complications due to adiposopathic endocrinopathies and/or immunopathies include cardiovascular disease, cancer, elevated blood sugar, elevated blood pressure, dyslipidemia, fatty liver, and alterations in sex hormones in both males (i.e., hypogonadism) and females (i.e., polycystic ovary syndrome). Obesity treatment begins with proactive steps to avoid weight bias, including patient-appropriate language, office equipment, and supplies. To help manage obesity and its complications, this CPS provides a practical template for an obesity medicine practice, creation of standard operating procedures, and incorporation of the OMA "ADAPT" method in telehealth (Assessment, Diagnosis, Advice, Prognosis, and Treatment).

Conclusions

The OMA CPS regarding "Obesity Definition, Diagnosis, Bias, Standard Operating Procedures (SOPs), and Telehealth" is one in a series of OMA CPSs designed to assist clinicians care for patients with the disease of obesity.

Gut Microbiome in Patients with Obstructive Sleep Apnoea

Background: Obstructive sleep apnoea (OSA) is a risk factor for cardiovascular disease. Alterations in the gut microbiome have been implicated in the development of cardiovascular disease and may potentially link OSA to its cardiovascular consequences. However, only one study to date has investigated gut microbiomes in adult patients with OSA. Methods: 19 patients with OSA and 20 non-OSA controls participated in the study. Following a diagnostic sleep study, blood was collected for metabolic profiling, and the subjects provided a stool sample for microbiome analysis. The gut microbiome was investigated using the 16S ribosomal RNA method. Results: Patients with OSA had a higher relative abundance of the Proteobacteria phylum (p = 0.03), Gammaproteobacteria class (p = 0.01), Lactobacillae family (p = 0.02), Lactobacillus (p = 0.03), and Roseburia genus (p = 0.03), and a lower abundance of the Actinobacteria phylum (p = 0.03). The abundance of Proteobacteria, Gammaproteobacteria, Lactobacillae, and Lactobacillus were related to disease severity and dyslipidaemia (all p < 0.05), whilst the abundance of Proteobacteria and Gammaproteobacteria was also related to hypertension and cardiovascular disease (all p < 0.05). However, following adjustment for relevant confounders only the association between OSA and Actinobacteria remained significant (p = 0.04). Conclusions: Obstructive sleep apnoea is associated with only subtle changes in gut microbiome. Further studies should investigate gut dysbiosis in OSA.

Leptin: A Potential Link Between Obstructive Sleep Apnea and Obesity

Chronic intermittent hypoxia (CIH), a pathophysiological manifestation of obstructive sleep apnea (OSA), is strongly correlated with obesity, as patients with the disease experience weight gain while exhibiting elevated plasma levels of leptin. This study was done to determine whether a relationship may exist between CIH and obesity, and body energy balance and leptin signaling during CIH. Sprague-Dawley rats were exposed to 96 days of CIH or normoxic control conditions, and were assessed for measures of body weight, food and water intake, and food conversion efficiency. At the completion of the study leptin sensitivity, locomotor activity, fat pad mass and plasma leptin levels were determined within each group. Additionally, the hypothalamic arcuate nucleus (ARC) was isolated and assessed for changes in the expression of proteins associated with leptin receptor signaling. CIH animals were found to have reduced locomotor activity and food conversion efficiency. Additionally, the CIH group had increased food and water intake over the study period and had a higher body weight compared to normoxic controls at the end of the study. Basal plasma concentrations of leptin were significantly elevated in CIH exposed animals. To test whether a resistance to leptin may have occurred in the CIH animals due to the elevated plasma levels of leptin, an acute exogenous (ip) leptin (0.04 mg/kg carrier-free recombinant rat leptin) injection was administered to the normoxic and CIH exposed animals. Leptin injections into the normoxic controls reduced their food intake, whereas CIH animals did not alter their food intake compared to vehicle injected CIH animals. Within ARC, CIH animals had reduced protein expression of the short form of the obese (leptin) receptor (isoform OBR₁₀₀) and showed a trend toward an elevated protein expression of the long form of obese (leptin) receptor (OBRb). In addition, pro-opiomelanocortin (POMC) protein expression was reduced, but increased expression of the phosphorylated extracellular-signal-regulated kinase 1/2 (pERK1/2) and of the suppressor of cytokine signaling 3 (SOCS3) proteins was observed in the CIH group, with little change in phosphorylated signal transducer and activator of transcription 3 (pSTAT3). Taken together, these data suggest that long-term exposure to CIH, as seen in obstructive sleep apnea, may contribute to a state of leptin resistance promoting an increase in body weight.

Could non-HDL-cholesterol be a better marker of atherogenic dyslipidemia in obstructive sleep apnea?

BACKGROUND/OBJECTIVE

Obstructive sleep apnea (OSA) is independently associated with dyslipidemia, a surrogate marker of atherosclerosis. Low-density lipoprotein (LDL)-cholesterol is accepted as a major independent risk factor for cardiovascular disease. However, non-high-density lipoprotein (HDL)-cholesterol is a better marker of atherogenic dyslipidemia and recommended as a target of lipid lowering therapy. We aimed to assess the prevalence of atherogenic dyslipidemia, and relationship between OSA severity and serum LDL-cholesterol and non-HDL cholesterol levels in OSA patients.

METHODS

We retrospectively evaluated treatment naïve 2361 subjects admitted to the sleep laboratory of a university hospital for polysomnography. All subjects' lipid profile including total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, and non-HDL-cholesterol were measured.

RESULTS

Out of 2361 patients (mean age 49.6 ± 11.9 years; 68.9% male, apnea-hypopnea index 36.6 ± 28.4/h), 185 (7.8%) had no OSA and 2176 (92.2%) had OSA. Atherogenic dyslipidemia prevalence was high (57-66%) in OSA patients, and especially increased in severe OSA compared to other groups (p < 0.05). Though total and LDL-cholesterol did not differ between those with and without OSA, non-HDL-cholesterol (p = 0.020), and triglycerides (p = 0.001) were higher and HDL-cholesterol levels (p = 0.018) were lower in OSA patients than non-OSA. Non-HDL-cholesterol was significantly correlated with OSA severity (p < 0.001) and hypoxia parameters (p < 0.01), whereas LDL-cholesterol showed no correlation.

CONCLUSIONS

Atherogenic dyslipidemia is highly prevalent and non-HDL-cholesterol levels are significantly increased, predominantly in severe OSA patients. Non-HDL-cholesterol but not LDL-cholesterol, is significantly correlated with OSA severity and hypoxia parameters. Therefore, it could be better to use non-HDL-cholesterol, which is a guideline recommended target of lipid therapy, as a marker of atherosclerotic cardiovascular risk in OSA patients.

Sleep duration, brain structure, and psychiatric and cognitive problems in children

Low sleep duration in adults is correlated with psychiatric and cognitive problems. We performed for the first time a large-scale analysis of sleep duration in children, and how this relates to psychiatric problems including depression, to cognition, and to brain structure. Structural MRI was analyzed in relation to sleep duration, and psychiatric and cognitive measures in 11,067 9-11-year-old children from the Adolescent Brain Cognitive Development (ABCD) Study, using a linear mixed model, mediation analysis, and structural equation methods in a longitudinal analysis. Dimensional psychopathology (including depression, anxiety, impulsive behavior) in the children was negatively correlated with sleep duration. Dimensional psychopathology in the parents was also correlated with short sleep duration in their children. The brain areas in which higher volume was correlated with longer sleep duration included the orbitofrontal cortex, prefrontal and temporal cortex, precuneus, and supramarginal gyrus. Longitudinal data analysis showed that the psychiatric problems, especially the depressive problems, were significantly associated with short sleep duration 1 year later. Further, mediation analysis showed that depressive problems significantly mediate the effect of these brain regions on sleep. Higher cognitive scores were associated with higher volume of the prefrontal cortex, temporal cortex, and medial orbitofrontal cortex. Public health implications are that psychopathology in the parents should be considered in relation to sleep problems in children. Moreover, we show that brain structure is associated with sleep problems in children, and that this is related to whether or not the child has depressive problems.

Physiological sleep measures predict time to 15-year mortality in community adults: Application of a novel machine learning framework

Clarifying whether physiological sleep measures predict mortality could inform risk screening; however, such investigations should account for complex and potentially non-linear relationships among health risk factors. We aimed to establish the predictive utility of polysomnography (PSG)-assessed sleep measures for mortality using a novel permutation random forest (PRF) machine learning framework. Data collected from the years 1995 to present are from the Sleep Heart Health Study (SHHS; n = 5,734) and the Wisconsin Sleep Cohort Study (WSCS; n = 1,015), and include initial assessments of sleep and health, and up to 15 years of follow-up for all-cause mortality. We applied PRF models to quantify the predictive abilities of 24 measures grouped into five domains: PSG-assessed sleep (four measures), self-reported sleep (three), health (eight), health behaviours (four), and sociodemographic factors (five). A 10-fold repeated internal validation (WSCS and SHHS combined) and external validation (training in SHHS; testing in WSCS) were used to compute unbiased variable importance metrics and associated p values. We observed that health, sociodemographic factors, and PSG-assessed sleep domains predicted mortality using both external validation and repeated internal validation. The PSG-assessed sleep efficiency and the percentage of sleep time with oxygen saturation <90% were among the most predictive individual measures. Multivariable Cox regression also revealed the PSG-assessed sleep domain to be predictive, with very low sleep efficiency and high hypoxaemia conferring the highest risk. These findings, coupled with the emergence of new low-burden technologies for objectively assessing sleep and overnight oxygen saturation, suggest that consideration of physiological sleep measures may improve risk screening.

The relationship between metabolic syndrome and obstructive sleep apnea syndrome: a nationwide population-based study

There has been a need for research on the association between metabolic syndrome (MetS) and obstructive sleep apnea syndrome (OSAS) using large data such as nationwide population-based data that adjusts important confounding factors. Therefore, we investigated the relationship between MetS and OSAS. The data source we used was the National Health Insurance Service claims database managed by the Republic of Korea government, in which 10,113,560 individuals were enrolled in 2009 and followed up until 2018. The independent association of MetS with the risk of OSAS was determined using a Cox proportional hazards model with adjustment for age, sex, smoking status, alcohol consumption, regular physical exercise, and body mass index. Our results showed that MetS were strongly associated to OSAS which was adjusted for several confounding factors. Also, we found men, increased waist circumference and increased triglyceride are important risk factors for OSAS.

The Role of Soluble Low-Density Lipoprotein Receptor-Related Protein-1 in Obstructive Sleep Apnoea

Intermittent hypoxia in obstructive sleep apnoea (OSA) is related to inflammation and metabolic abnormalities. Soluble low-density lipoprotein receptor-related protein-1 (sLRP-1) is involved in anti-inflammatory and metabolic processes. However, its ligand, calreticulin (CALR) promotes pro-inflammatory responses and apoptosis. Our aim was to analyse the levels of these biomarkers in OSA. We recruited 46 patients with OSA and 30 control subjects. Inpatient sleep study was performed and fasting plasma samples were collected. Triglyceride glucose index (TyG) and atherogenic index of plasma (AIP) were calculated. Plasma sLRP-1 levels were significantly lower in the OSA group compared to the controls (1.67 (0.90–2.11) mg/L vs. 1.99 (1.53–3.51) mg/L; p = 0.04) after adjustment for age, gender, BMI and lipid profile. Plasma sLRP-1 concentrations were inversely related to age (r = −0.29), BMI (r = −0.35), cigarette pack years (r = −0.31), LDL-C (r = −0.34) and triglyceride levels (r = −0.27), TyG (r = −0.37) and AIP (r = −0.27) as well as to the oxygen desaturation index (ODI, r = −0.24; all p < 0.05). BMI (p = 0.01) and ODI (p = 0.04) were independent predictors for low sLRP-1 levels. CALR did not differ significantly between the two groups (0.23 (0.17–0.34) ng/mL vs. 0.24 (0.20–0.36) ng/mL p = 0.76). We detected lower sLRP-1 levels in subjects with OSA which could contribute to metabolic abnormalities associated with this disease.

Obstructive Sleep Apnea-hypopnea Syndrome as a Novel Potential Risk for Aging

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a common sleep disorder, negatively influencing individuals' quality of life and socioeconomic burden. In recent years, OSAHS has been reported in not only constituting an aging-associated disease, but also in accelerating and/or potentiating aging mechanisms. However, the negative impacts of OSAHS on aging are underestimated because of low level of public awareness about this disease and high rates of undiagnosed cases, which are more critical in developing countries or economically disadvantaged regions. Hence, reviewing previously reported observations may assist scholars to better indicate that OSAHS is likely a novel potential risk for aging. Further understanding of the pathophysiological mechanism of OSAHS and its role in procession of aging may markedly highlight the importance of this common sleep disorder.

Childhood Obesity and Respiratory Diseases: Which Link?

Prevalence of childhood obesity is progressively increasing, reaching worldwide levels of 5.6% in girls and of 7.8% in boys. Several evidences showed that obesity is a major preventable risk factor and disease modifier of some respiratory conditions such as asthma and Obstructive Sleep Apnea Syndrome (OSAS). Co-occurrence of asthma and obesity may be due to common pathogenetic factors including exposure to air pollutants and tobacco smoking, Western diet, and low Vitamin D levels. Lung growth and dysanapsis phenomenon in asthmatic obese children play a role in impaired respiratory function which appears to be different than in adults. Genes involved in both asthma and obesity have been identified, though a gene-by-environment interaction has not been properly investigated yet. The identification of modifiable environmental factors influencing gene expression through epigenetic mechanisms may change the natural history of both diseases. Another important pediatric respiratory condition associated with obesity is Sleep-Disordered Breathing (SDB), especially Obstructive Sleep Apnea Syndrome (OSAS). OSAS and obesity are linked by a bidirectional causality, where the effects of one affect the other. The factors most involved in the association between OSAS and obesity are oxidative stress, systemic inflammation, and gut microbiota. In OSAS pathogenesis, obesity's role appears to be mainly due to mechanical factors leading to an increase of respiratory work at night-time. However, a causal link between obesity-related inflammatory state and OSAS pathogenesis still needs to be properly confirmed. To prevent obesity and its complications, family education and precocious lifestyle changes are critical. A healthy diet may lead to an improved quality of life in obese children suffering from respiratory diseases. The present review aimed to investigate the links between obesity, asthma and OSAS, focusing on the available evidence and looking for future research fields.

Atherogenic Index of Plasma in Obstructive Sleep Apnoea

Background: Dyslipidaemia is well recognised in obstructive sleep apnoea (OSA) and could contribute to the development of cardiovascular disease (CVD). Atherogenic index of plasma (AIP) predicts cardiovascular morbidity and mortality better than the individual lipid levels. The aim of this study was to investigate the AIP in patients with OSA in relation with disease severity. Methods: Four hundred sixty-one patients with OSA and 99 controls participated in this study. AIP was assessed in the morning following a diagnostic sleep study. The association between lipid values and OSA were adjusted for age, gender, and body mass index. Results: Patients with OSA had higher AIP and triglyceride, and lower high-density lipoprotein cholesterol (HDL-C) levels (all p < 0.05). AIP significantly correlated with the Epworth Sleepiness Scale score (ρ = 0.19), the apnoea-hypopnoea index (ρ = 0.40) and oxygen desaturation index (ρ = 0.43, all p < 0.05). However, there was no relationship between the AIP and markers of sleep quality such as total sleep time, sleep period time, sleep efficiency, arousal index or percentage of REM sleep (all p > 0.05). AIP was not a better predictor for self-reported cardiovascular disease or diabetes than HDL-C. Conclusions: AIP is elevated in OSA and is related to disease severity. However, it does not seem to have an additional clinical value compared to HDL-C.

Circulating exosomes and gut microbiome induced insulin resistance in mice exposed to intermittent hypoxia: Effects of physical activity

Background

Gut microbiota (GM) contribute to obesity and insulin resistance (IR). Obstructive sleep apnea (OSA), characterized by intermittent hypoxia (IH), promotes IR and alters GM. Since circulating exosomes are implicated in IR, we examined the effects of IH and physical activity (PA) in mice on GM, colonic epithelium permeability, systemic IR, and plasma exosome cargo, and exosome effects on visceral white adipose tissues (vWAT) IR.

Methods

C57BL/6 mice were exposed to IH or room air (RA) for 6 weeks with and without PA (n = 12/group), and GM and systemic IR changes were assessed, as well as the effects of plasma exosomes on naïve adipocyte insulin sensitivity. Fecal microbiota transfers (FMT) were performed in naïve mice (n = 5/group), followed by fecal 16S rRNA sequencing, and systemic IR and exosome-induced effects on adipocyte insulin sensitivity were evaluated.

Findings

Principal coordinate analysis (PCoA) ordinates revealed B-diversity among IH and FMT recipients that accounted for 64% principal component 1 (PC1) and 12.5% (PC2) of total variance. Dominant microbiota families and genera in IH-exposed and FMT-treated were preserved, and IH-exposed GM and IH-FMT induced increased gut permeability. Plasma exosomes from IH-exposed and IH-FMT mice decreased pAKT/AKT responses to exogenous insulin in adipocytes vs. IH+PA or RA FMT-treated mice (p = 0.001).

Interpretation

IH exposures mimicking OSA induce changes in GM, increase gut permeability, and alter plasma exosome cargo, the latter inducing adipocyte dysfunction (increased IR). Furthermore, these alterations improved with PA. Thus, IH leads to perturbations of a singular GM-circulating exosome pathway that disrupts adipocyte homeostasis resulting in metabolic dysfunction, as reflected by IR.

Funding

This study was supported by grants from the National Institutes of Health grants HL130984 and HL140548 and University of Missouri Tier 2 grant. The study has not received any funding or grants from pharmaceutical or other industrial corporations.

Transcriptomic Changes of Murine Visceral Fat Exposed to Intermittent Hypoxia at Single Cell Resolution

Intermittent hypoxia (IH) is a hallmark of obstructive sleep apnea (OSA) and induces metabolic dysfunction manifesting as inflammation, increased lipolysis and insulin resistance in visceral white adipose tissues (vWAT). However, the cell types and their corresponding transcriptional pathways underlying these functional perturbations are unknown. Here, we applied single nucleus RNA sequencing (snRNA-seq) coupled with aggregate RNA-seq methods to evaluate the cellular heterogeneity in vWAT following IH exposures mimicking OSA. C57BL/6 male mice were exposed to IH and room air (RA) for 6 weeks, and nuclei from vWAT were isolated and processed for snRNA-seq followed by differential expressed gene (DEGs) analyses by cell type, along with gene ontology and canonical pathways enrichment tests of significance. IH induced significant transcriptional changes compared to RA across 14 different cell types identified in vWAT. We identified cell-specific signature markers, transcriptional networks, metabolic signaling pathways, and cellular subpopulation enrichment in vWAT. Globally, we also identify 298 common regulated genes across multiple cellular types that are associated with metabolic pathways. Deconvolution of cell types in vWAT using global RNA-seq revealed that distinct adipocytes appear to be differentially implicated in key aspects of metabolic dysfunction. Thus, the heterogeneity of vWAT and its response to IH at the cellular level provides important insights into the metabolic morbidity of OSA and may possibly translate into therapeutic targets.

Common risk factors and therapeutic targets in obstructive sleep apnea and osteoarthritis: An unexpectable link?

Osteoarthritis (OA) and Obstructive Sleep Apnea (OSA) are two highly prevalent chronic diseases for which effective therapies are urgently needed. Recent epidemiologic studies, although scarce, suggest that the concomitant occurrence of OA and OSA is associated with more severe manifestations of both diseases. Moreover, OA and OSA share risk factors, such as aging and metabolic disturbances, and co-morbidities, including cardiovascular and metabolic diseases, sleep deprivation and depression. Whether this coincidental occurrence is fortuitous or involves cause-effect relationships is unknown. This review aims at collating and integrating present knowledge on both diseases by providing a brief overview of their epidemiology and pathophysiology, analyzing current evidences relating OA and OSA and discussing potential common mechanisms by which they can aggravate each other. Such mechanisms constitute potential therapeutic targets whose pharmacological modulation may provide more efficient ways of reducing the consequences of OA and OSA and, thus, lessen the huge individual and social burden that they impose.

The Co-occurrence of Pediatric Obesity and ADHD: an Understanding of Shared Pathophysiology and Implications for Collaborative Management

PURPOSE OF REVIEW

To describe what is known about the association between obesity and attention-deficit hyperactivity disorder (ADHD) in children along with the co-occurring conditions of sleep dysfunction, loss of control/binge eating disorder (LOC-ED/BED), and anxiety.

RECENT FINDINGS

Obesity and ADHD share common brain pathways (hypothalamic, executive, and reward centers) with pathophysiology in these areas manifesting in partial or complete expression of these diseases. Sleep dysfunction, LOC-ED/BED, and anxiety share similar pathways and are associated with this disease dyad. The association of obesity and ADHD with sleep dysfunction, LOC-ED/BED, and anxiety is discussed. An algorithm outlining decision pathways for patients with obesity and with and without ADHD is presented. Future research exploring the complex pathophysiology of both obesity and ADHD as well as co-occurring conditions is needed to develop clinical guidelines and ultimately assist in providing the best evidence-based care.

The Burden of Associated Comorbidities in Patients with Obstructive Sleep Apnea-Regional Differences in Two Central-Eastern European Sleep Centers

Background: Obstructive sleep apnea (OSA) is usually associated with cardiovascular and cerebrovascular disease, metabolic syndrome and depression. Data on relevant OSA-associated comorbidities in Central–European populations are scarce. The aim of this study was to compare the prevalence of comorbidities in two OSA cohorts from Hungary and Romania. Methods: Data from 588 (282 from Hungary, 306 from Romania) untreated patients with OSA were retrospectively analyzed. The prevalence rates of hypertension, diabetes, dyslipidemia, allergic rhinitis, asthma, chronic obstructive pulmonary disease (COPD), osteoporosis, cerebrovascular and cardiovascular disease, arrhythmia and depression were compared between the two populations following adjustment for demographics, body mass index, smoking history, comorbidities and sleep parameters. Results: The prevalence rates of hypertension, arrhythmia, cerebrovascular and cardiovascular disease, diabetes and COPD in the whole study population were directly related to the severity of OSA. We found an inverse correlation between the prevalence of osteoporosis and OSA severity (all p < 0.05). Following adjustment, the prevalence of dyslipidemia was higher in the Hungarian cohort, whilst the prevalence of asthma, cardiovascular and cerebrovascular diseases was higher in the Romanian cohort (all p < 0.05). Conclusions: There was no difference in the prevalence rate of most comorbidities in patients with OSA from the two cohorts, except for dyslipidemia, asthma, cardiovascular and cerebrovascular disease.

Gut microbiota composition in children with obstructive sleep apnoea syndrome: a pilot study

BACKGROUND

Obstructive Sleep Apnoea syndrome (OSAS) is considered a systemic inflammatory disease and is characterized by intermittent hypoxia that can damage the integrity of intestinal barrier and alter gut microbiota composition in adults and animal models. To date there is only one study on snoring children and microbiota but no studies are present on paediatric OSAS related dysbiosis.

STUDY OBJECTIVES

To evaluate gut microbiota composition in OSAS children in respect to healthy subjects and investigate the role of sleep parameters in changing gut microbiome.

METHODS

Sixteen children divided in OSAS and healthy groups. Stool samples were collected from both the two groups to assess gut microbiota composition using 16S rRNA sequencing and a nocturnal pulsossimetry and polysomnography were performed in OSAS children.

RESULTS

OSAS children showed a decreased microbial diversity in respect to healthy subjects in terms of number of observed species and Chao1 index (p = 0,01). Firmicutes/Bacteroidetes ratio was directly correlated to Sleep Clinical Record (p = 0,03). The abundance of several inflammation-related strains (Proteobacteria, Clostridiaceae, Oscillospiraceae, Klebsiella) were found significantly modified in relation to sleep parameters. Bacteria implied in the gut barrier integrity (Desulfovibrionaceae, Bacteroides fragilis and Faecalibacterium prausnitzii) were found significantly different in the two study groups and correlated with sleep parameters.

CONCLUSIONS

OSAS children showed a lower microbiota diversity in respect to heathy subjects and an increase of inflammation and gut barrier disruptors-related strains probably induced by intermittent hypoxia. Further studies should be conducted to understand the role of gut microbiota in OSAS physiopathology and comorbidities in children.