Pediatric OSA Syndrome Morbidity Biomarkers: The Hunt Is Finally On!

Characteristics and clinical value of intestinal metabolites in 4 to 6-year-old children with OSAHS

OBJECTIVE

This study aims to explore the characteristics and functional changes of intestinal metabolites in children with obstructive sleep apnea hypopnea syndrome (OSAHS) aged 4-6 years old through metabolomic approaches, screen potential biomarkers and analyze their correlation with clinical indicators and preliminary discuss the roles of intestinal metabolites in the occurrence and development of OSAHS.

METHODS

We collected fecal samples from 40 OSAHS children and 40 healthy controls aged 4-6 years and recorded some OSAHS-related clinical indicators. Fecal specimens were used to detect all metabolites through untargeted metabolomics.

RESULTS

This study identified a total of 1164 intestinal metabolites and screened out 254 differential metabolites. In the OSAHS group, the relative content of 96 metabolites were higher than the control group, while the relative content of 158 metabolites were lower. The receiver operating characteristic curve analysis results showed that the area under the curve of 14 differential metabolites was greater than 0.8. The area under the curve of Formononetin is the highest, at 0.9100, with sensitivity and specificity of 82.5% and 90.0%, respectively, and is positively correlated with OAHI. The differential metabolite functions mainly include the metabolism of fatty acids and other lipid substances, cellular signaling, protein and amino acid related metabolism, disease-related functions, glucose metabolism, and vitamin metabolism.

CONCLUSION

The intestinal metabolites and metabolic function of 4-to-6-year-old children with OSAHS altered. There was a correlation between differential metabolites and clinical indicators such as uric acid, hemoglobin, and blood sugar, which has potential diagnostic value for OSAHS screening.

The Past and Future of Sleep Medicine

The past of sleep medicine is rich with seminal discoveries, from the recognition of clinical syndromes to measurement of sleep itself to classic and novel therapeutics. Advances in neurobiology have mapped a number of sleep circuits, described the central and peripheral circadian system, and identified the cause of narcolepsy with cataplexy. Sleep apnea endotypes and phenotypes now have established clinical relevance, though treatment implications are a work in progress. Artificial intelligence will continue to change sleep medicine in a number of domains from aiding scoring to health outcome predictions. There is a large gap between the known science and clinical translational.

Quantitative Proteomics Analysis of Serum and Urine With DIA Mass Spectrometry Reveals Biomarkers for Pediatric Obstructive Sleep Apnea

OBJECTIVES

Identification of suitable biomarkers that facilitate the screening and evaluation of pediatric obstructive sleep apnea (OSA) and its severity was explored.

METHODS

Data-independent acquisition quantitative proteomic analysis was employed to identify serum and urine proteins with differential expression patterns between children with OSA and controls. Differentially expressed proteins that gradually increased or decreased with the severity of OSA were retained as potential biomarkers and underwent ELISA validation.

RESULTS

We found that with increasing severity of OSA, there was a gradual upregulation of 34 proteins in the serum and 124 proteins in the urine, along with a respective downregulation of 10 serum proteins and 64 urinary proteins in the initial cohort of 40 children. These proteins primarily participate in immune activation, the complement pathway, oxygen transport, and reactive oxygen metabolism. Notably, cathepsin Z exhibited a positive correlation with the obstructive apnea hypopnea index, whereas sex hormone-binding globulin (SHBG) was negatively correlated. These proteins were then validated by ELISA in an independent cohort (n=21). Circulating cathepsin Z and SHBG levels displayed acceptable diagnostic performance of OSA with AUC values of 0.863 and 0.738, respectively.

CONCLUSIONS

We identified two promising circulating proteins as novel biomarkers for clinical diagnosis and assessment of pediatric OSA severity. Furthermore, the comprehensive proteomic profile in pediatric OSA should aid in exploring the underlying pathophysiological mechanisms associated with this prevalent condition.

A narrative review on obstructive sleep apnoea syndrome in paediatric population

Obstructive sleep apnoea syndrome is a respiratory sleep disorder that affects 1-5% of children. It occurs equally in males and females, with higher incidence in school age and adolescence. OSAS may be caused by several factors, but in children, adenotonsillar hypertrophy, obesity, and maxillo-mandibular deficits are the most common. In general, there is a reduction in the diameter of the airway with reduced airflow. This condition worsens during sleep due to the muscular hypotonia, resulting in apnoeas or hypoventilation. While snoring is the primary symptom, OSAS-related manifestations have a wide spectrum. Some of these symptoms relate to the nocturnal phase, including disturbed sleep, frequent changes of position, apnoeas and oral respiration. Other symptoms concern the daytime hours, such as drowsiness, irritability, inattention, difficulties with learning and memorisation, and poor school performance, especially in patient suffering from overlapping syndromes (e.g., Down syndrome). In some cases, the child's general growth may also be affected. Early diagnosis of this condition is crucial in limiting associated symptoms that can significantly impact a paediatric patient's quality of life, with the potential for the condition to persist into adulthood. Diagnosis involves evaluating several aspects, beginning with a comprehensive anamnesis that includes specific questionnaires, followed by an objective examination. This is followed by instrumental diagnosis, for which polysomnography is considered the gold standard, assessing several parameters, including the apnoea-hypopnoea index (AHI) and oxygen saturation. However, it is not the sole tool for assessing the characteristics of this condition. Other possibilities, such as night-time video recording, nocturnal oximetry, can be chosen when polysomnography is not available and even tested at home, even though with a lower diagnostic accuracy. The treatment of OSAS varies depending on the cause. In children, the most frequent therapies are adenotonsillectomy or orthodontic therapies, specifically maxillary expansion.

Inhibiting the CB1 receptor in CIH-induced animal model alleviates colon injury

Obstructive sleep apnea (OSA) can lead to intestinal injury, endotoxemia, and disturbance of intestinal flora. Additionally, as a crucial component of the endocannabinoid system, some studies have demonstrated that cannabinoid 1 (CB1) receptors are closely linked to the multiple organ dysfunction triggered by OSA. However, the role of the CB1 receptor in alleviating OSA-induced colon injury remains unclear. Here, through the construction of the OSA classic model, we found that the colon tissue of chronic intermittent hypoxia (CIH)-induced mice exhibited an overexpression of the CB1 receptor. The results of hematoxylin-eosin staining and transmission electron microscopy revealed that inhibition of the CB1 receptor could decrease the gap between the mucosa and muscularis mucosae, alleviate mitochondrial swelling, reduce microvilli shedding, and promote the recovery of tight junctions of CIH-induced mice. Furthermore, CB1 receptor inhibition reduced the levels of metabolic endotoxemia and inflammatory responses, exhibiting significant protective effects on the colon injury caused by CIH. At the molecular level, through western blotting and real-time polymerase chain reaction techniques, we found that inhibiting the CB1 receptor can significantly increase the expression of ZO-1 and Occludin proteins, which are closely related to the maintenance of intestinal mucosal barrier function. Through 16S rRNA high-throughput sequencing and short-chain fatty acid (SCFA) determination, we found that inhibition of the CB1 receptor increased the diversity of the microbial flora and controlled the makeup of intestinal flora. Moreover, butyric acid concentration and the amount of SCFA-producing bacteria, such as Ruminococcaceae and Lachnospiraceae, were both markedly elevated by CB1 receptor inhibition. The results of the spearman correlation study indicated that Lachnospiraceae showed a positive association with both ZO-1 and Occludin but was negatively correlated with the colon CB1 receptor, IL-1β, and TNF-α. According to this study, we found that inhibiting CB1 receptor can improve CIH-induced colon injury by regulating gut microbiota, reducing mucosal damage and promoting tight junction recovery. KEY POINTS: •CIH leads to overexpression of CB1 receptor in colon tissue. •CIH causes intestinal flora disorder, intestinal mucosal damage, and disruption of tight junctions. •Inhibition of CB1 receptor can alleviate the colon injury caused by CIH through regulating the gut microbiota, reducing mucosal injury, and promoting tight junction recovery.

Recent progresses in gut microbiome mediates obstructive sleep apnea-induced cardiovascular diseases

Obstructive sleep apnea (OSA) is a multifactorial sleep disorder with a high prevalence in the general population. OSA is associated with an increased risk of developing cardiovascular diseases (CVDs), particularly hypertension, and is linked to worse outcomes. Although the correlation between OSA and CVDs is firmly established, the mechanisms are poorly understood. Continuous positive airway pressure is primary treatment for OSA reducing cardiovascular risk effectively, while is limited by inadequate compliance. Moreover, alternative treatments for cardiovascular complications in OSA are currently not available. Recently, there has been considerable attention on the significant correlation between gut microbiome and pathophysiological changes in OSA. Furthermore, gut microbiome has a significant impact on the cardiovascular complications that arise from OSA. Nevertheless, a detailed understanding of this association is lacking. This review examines recent advancements to clarify the link between the gut microbiome, OSA, and OSA-related CVDs, with a specific focus on hypertension, and also explores potential health advantages of adjuvant therapy that targets the gut microbiome in OSA.

Analysis of the Clinical Course of Children With Initial Negative Polysomnography

OBJECTIVES

To determine the clinical course of children with initial negative polysomnography (PSG) tests.

METHODS

A retrospective chart review was performed on pediatric patients seen by an otolaryngologist who underwent a PSG between October 2012 and March 2019 for obstructive sleep apnea at a single, academic, tertiary-care center. Data including demographics, follow-up PSG tests, and surgeries were collected.

RESULTS

A total of 2018 pediatric patients underwent PSG during the timeframe. About 535/2018 (26.5%) patients were negative for obstructive sleep apnea by PSG and had no prior adenotonsillectomy. About 408/535 (76.3%) did not obtain follow-up testing or surgeries; 69/535 (12.9%) underwent subsequent adenotonsillectomy for worsening symptoms without repeat PSG; and 58/535 (10.8%) obtained 1 or multiple follow-up PSG tests. Of the 58 who obtained repeat PSG, 25 (43.1%) were subsequently positive, with 17 of those 25 (29.3% of 58) undergoing adenotonsillectomy. Taken together, 94/535 (17.6%) of patients with initial negative PSG had worsening sleep disordered breathing.

CONCLUSION

A significant minority of children who initially tested negative for pediatric obstructive sleep apnea met criteria for diagnosis on follow up PSG. Additionally, other children with initial negative PSG underwent adenotonsillectomy for worsening symptoms in lieu of repeat testing. Patients should be educated that snoring in children could persist or worsen over time, even in the setting of a initial negative PSG.

Outcomes after metabolic and bariatric surgery in preteens versus teens using the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program database and center-specific data

OBJECTIVE

The American Academy of Pediatrics (AAP) recently released clinical guidelines for the treatment of childhood obesity, including surgery being appropriate for children 13 years of age and older. The use of this age cut-off was due to a lack of data for children younger than 13. To address this knowledge gap, the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database was queried to compare outcomes in preteens to teens after bariatric surgery hypothesizing that there would be no difference in outcomes between the two groups.

METHODS

Patients from the MSAQIP database (2016-2021) were identified and divided into groups <13 years and 13-18 years and were matched using propensity scores based on race, sex, and preoperative BMI. Outcomes were compared including change in BMI, complication rates, 30-day readmission or reoperation, and mortality. Additionally, the centers responsible for the bulk of the preteen patient entries queried their center-specific databases to evaluate weight loss over time.

RESULTS

A total of 4755 patients were identified, 47 of whom were <13 years of age. Preteens had similar sex distribution (66% vs. 75% female), were more likely to be Black (27.7% vs. 18.3%) or Hispanic (21.3% vs. 7.6%) race, and weighed less (274 ± 58 vs. 293 ± 85 lb, p = 0.01), but they had similar BMI (46.9 ± 7 vs. 47 ± 13 kg/m2 ) as their teen counterparts. Preteens were more likely to suffer from sleep apnea (34% vs. 19%, p < 0.01) and insulin-dependent type 2 diabetes (10.6% vs. 1.8%, p < 0.01). There were no complications in the preteens compared to teens (0% vs. 0.5%), and they did not undergo any unplanned readmissions (0% vs. 2.9%) or reoperations (0% vs. 0.8%) within 30 days of surgery. There were also no mortalities reported in preteens (0% vs. 0.1%). The risk-adjusted decrease in BMI between preteens and teens was also comparable at 30 days (4.2 [95% CI: 3.0-5.4] vs. 4.6 [95% CI: 4.4-4.7], p = 0.6). Decrease in BMI in preteens was 7 ± 3 kg/m2 at 3 months and 9 ± 4 kg/m2 at 12 months after surgery, which represented a percentage BMI change of 16 ± 7 and 20 ± 8, respectively.

CONCLUSIONS

This study demonstrates that bariatric surgery in preteens is safe and efficacious when performed at specialized centers, and that age criteria may not be required. The AAP and others are encouraged to include age cut-offs in their guidelines for children with obesity and bariatric surgery only when data are available to support their inclusion.

Evaluation and diagnosis of pediatric obstructive sleep apnea—An update

Purpose

Formal overnight polysomnography (PSG) is required to diagnose obstructive sleep apnea (OSA) in children with sleep disordered breathing (SDB). Most clinical guidelines do not recommend home-based tests for pediatric OSA. However, PSG is limited by feasibility, cost, availability, patient discomfort, and resource utilization. Additionally, the role of PSG in evaluating disease impact may need to be revised. There is a strong need for alternative testing that can stratify the need for PSG and improve the time to diagnosis of OSA. This narrative review aims to evaluate and discuss innovative approaches to pediatric SDB diagnosis.

Findings

Methods to evaluate pediatric SDB outside of PSG include validated questionnaires, single-channel recordings, incorporation of telehealth, home sleep apnea testing (HSAT), and predictive biomarkers. Despite the promise, no individual metric has been found suitable to replace standard PSG. In addition, their use in combination to diagnose OSA diagnosis still needs to be defined.

Summary

When combined with adjunct assessments, HSAT advancements may accurately evaluate SDB in children and thus minimize the need for overnight in-laboratory PSG. Further studies are required to confirm diagnostic validity vis-à-vis PSG as a reference standard.

Sleep-Disordered Breathing among Saudi Primary School Children: Incidence and Risk Factors

This study aimed to identify the incidence and risk factors of sleep-disordered breathing (SDB) using an Arabic version of the pediatric sleep questionnaire (PSQ). A total of 2000 PSQs were circulated to children aged 6-12 years who were randomly selected from 20 schools in Al-Kharj city, Saudi Arabia. The questionnaires were filled out by the parents of participating children. The participants were further divided into two groups (younger group: 6-9 years and older group: 10-12 years). Out of 2000 questionnaires, 1866 were completed and analyzed (93.3% response rate), of which 44.2% were from the younger group and 55.8% were from the older group. Among all the participants, a total of 1027 participants were female (55%) and 839 were male (45%) with a mean age of 9.67 ± 1.78 years. It showed that 13% of children were suffering from a high risk of SDB. Chi-square test and logistic regression analyses within this study cohort showed a significant association between SDB symptoms (habitual snoring; witnessed apnea; mouth breathing; being overweight; and bedwetting) and risk of developing SDB. In conclusion: habitual snoring; witnessed apnea; mouth breathing; being overweight; and bedwetting strongly contribute the to development of SDB.

Single-cell RNA-seq uncovers cellular heterogeneity and provides a signature for paediatric sleep apnoea

BACKGROUND

Obstructive sleep apnoea (OSA) is a highly prevalent disease and a major cause of systemic inflammation leading to neurocognitive, behavioural, metabolic and cardiovascular dysfunction in children and adults. However, the impact of OSA on the heterogeneity of circulating immune cells remains to be determined.

METHODS

We applied single-cell transcriptomics analysis (scRNA-seq) to identify OSA-induced changes in transcriptional landscape in peripheral blood mononuclear cell (PBMC) composition, which uncovered severity-dependent differences in several cell lineages. Furthermore, a machine-learning approach was used to combine scRNAs-seq cell-specific markers with those differentially expressed in OSA.

RESULTS

scRNA-seq demonstrated OSA-induced heterogeneity in cellular composition and enabled the identification of previously undescribed cell types in PBMCs. We identified a molecular signature consisting of 32 genes, which distinguished OSA patients from various controls with high precision (area under the curve 0.96) and accuracy (93% positive predictive value and 95% negative predictive value) in an independent PBMC bulk RNA expression dataset.

CONCLUSION

OSA deregulates systemic immune function and displays a molecular signature that can be assessed in standard cellular RNA without the need for pre-analytical cell separation, thereby making the assay amenable to application in a molecular diagnostic setting.

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.

Alterations in Inflammatory Markers and Cognitive Ability after Treatment of Pediatric Obstructive Sleep Apnea

Background and Objectives: Determination of the impact of obstructive sleep apnea (OSA) on the cognitive function (CF), and serum tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and 1β levels and the effect of OSA management on these variables in children. Materials and Methods: A total of 224 patients were evaluated using the Pediatric Sleep Questionnaire, the NEPSY score for CF, and polysomnography (PSG) to grade OSA severity according to the apnea/hypopnea index (AHI). Adentonsillectomy (AT) was performed for patients with adenotonsillar hypertrophy grade > 2. Patients with overweight or obesity with mild or moderate OSAS underwent a 6-month protocol of lifestyle intervention (LSI). Blood samples were obtained for an enzyme-linked immunosorbent assay (ELISA) estimation of cytokine levels. All variables were re-evaluated at the end of the 6-month follow-up period. Results: A total of 181 patients had surgical interference and 43 patients underwent a LSI trial; 15 patients failed to respond and underwent surgery. At the end of the follow-up, 33 patients had residual OSAS with a significantly higher incidence among patients with severe OSAS, the mean score of the pediatric sleep questionnaire was significantly decreased in all patients, 181 patients showed an improved NESPY score, and cytokine levels were decreased. The baseline NESPY score, AHI index and sleep questionnaire score were negatively correlated. The percentage of change in the NESPY score and serum cytokine levels showed a positive correlation. Conclusions: OSAS is associated with cognitive dysfunction that significantly improves after adenotonsillectomy. LSI as a therapeutic line is satisfactory for children with mild OSAS and minimal cognitive dysfunction and is of value preoperatively to improve the surgical outcomes of AT.

Demonstration of Accuracy and Feasibility of Remotely Delivered Oximetry: A Blinded, Controlled, Real-World Study of Regional/Rural Children with Obstructive Sleep Apnoea

Objectives: Evaluate diagnostic accuracy and feasibility of a mail-out home oximetry kit. Design: Patients were referred for both the tertiary/quaternary-centre hospital-delivered oximetry (HDO) and for the mail-out remotely-delivered oximetry (RDO). Quantitative and qualitative data were collected. The COVID-19 pandemic began during this study; therefore, necessary methodological adjustments were implemented. Setting: Patients were first evaluated in Swan Hill, Victoria. RDO kits were sent to home addresses. For the HDO, patients travelled to the Melbourne city area, received the kit, stayed overnight, and returned the kit the following morning. Participants: All consecutive paediatric patients (aged 2−18), diagnosed by a specialist in Swan Hill with obstructive sleep apnoea (OSA) on history/examination, and booked for tonsillectomy +/− adenoidectomy, were recruited. Main outcome measures: Diagnostic accuracy (i.e., comparison of RDO to HDO results) and test delivery time (i.e., days from consent signature to oximetry delivery) were recorded. Patient travel distances for HDO collection were calculated using home/delivery address postcodes and Google® Maps data. Qualitative data were collected with two digital follow-up surveys. Results: All 32 patients that had both the HDO and RDO had identical oximetry results. The HDO mean delivery time was 87.7 days, while the RDO mean delivery time was 23.6 days (p value: <0.001). Qualitatively, 3/28 preferred the HDO, while 25/28 preferred the RDO (n = 28). Conclusions: The remote option is as accurate as the hospital option, strongly preferred by patients, more rapidly completed, and also an ideal investigation delivery method during certain emergencies, such as the COVID-19 pandemic.

Neurocognitive Consequences in Children with Sleep Disordered Breathing: Who Is at Risk?

Sleep-disordered breathing (SDB) is a prevalent disease in children characterized by snoring and narrowing of the upper airway leading to gas exchange abnormalities during sleep as well as sleep fragmentation. SDB has been consistently associated with problematic behaviors and adverse neurocognitive consequences in children but causality and determinants of susceptibility remain incompletely defined. Since the 1990s several studies have enlightened these associations and consistently reported poorer academic performance, lower scores on neurocognitive tests, and behavioral abnormalities in children suffering from SDB. However, not all children with SDB develop such consequences, and severity of SDB based on standard diagnostic indices has often failed to discriminate among those children with or without neurocognitive risk. Accordingly, a search for discovery of markers and clinically useful tools that can detect those children at risk for developing cognitive and behavioral deficits has been ongoing. Here, we review the advances in this field and the search for possible detection approaches and unique phenotypes of children with SDB who are at greater risk of developing neurocognitive consequences.

Cardiometabolic risk profile in non-obese children with obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) in childhood is a complex disease primarily due both to adenotonsillar hypertrophy and pediatric obesity. Notably, inflammation has been recognized as one of the most important shared pathogenic factor between obesity and OSAS resulting in an increased cardiometabolic risk for these patients. To date, evidence is still limited in non-obese population with OSAS. We aimed to evaluate the cardiometabolic risk profile of a pediatric population of non-obese subjects affected by OSAS. A total of 128 school-aged children (mean age 9.70 ± 3.43) diagnosed with OSAS and 213 non-OSAS children (mean age 9.52 ± 3.35) as control group were enrolled. All subjects underwent a complete clinical and biochemical assessment (including white blood cell count (WBC), platelet count (PLT), mean platelet volume (MPV), % of neutrophils (NEU%), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), serum glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transpeptidase (GGT), uric acid, fasting insulin, iron, ferritin, and transferrin levels). A significant association between inflammation markers (including WBC, PLT, MPV, NEU%, ferritin, CPR, and ESR) and OSAS was found (all p < 0.001). Children with OSAS also showed increased transaminase, glucose, uric acid, and insulin levels (all p < 0.001) compared to healthy controls.

CONCLUSION

Taken together, these findings suggested a worse cardiometabolic profile in non-obese children with OSAS. Given the pivotal pathogenic role of inflammation both for hypoxiemia and metabolic derangements, therapeutic strategies for OSAS might also counteract the increased cardiometabolic risk of these patients, by improving their long-term quality of life.

WHAT IS KNOWN

• Pediatric OSAS has shown a close relationship with obesity and its cardiometabolic comorbidities. • Inflammation represents the hallmark of both obesity and OSAS.

WHAT IS NEW

• Non obese children with OSAS presented with a worse cardiometabolic risk profile. • OSAS treatment might serve as an effective approach also for the increased cardiometabolic risk of these children.

You Cannot Hit Snooze on OSA: Sequelae of Pediatric Obstructive Sleep Apnea

Pediatric obstructive sleep apnea (OSA) has been shown to not only affect the quality of sleep, but also overall health in general. Untreated or inadequately treated OSA can lead to long-term sequelae involving cardiovascular, endothelial, metabolic, endocrine, neurocognitive, and psychological consequences. The physiological effects of pediatric OSA eventually become pathological. As the complex effects of pediatric OSA are discovered, they must be identified early so that healthcare providers can be better equipped to treat and even prevent them. Ultimately, adequate management of OSA improves overall quality of life.

Erythropoietin levels in children with obstructive sleep apnea

OBJECTIVE

High serum erythropoietin (EPO) levels have been reported in adult patients with obstructive sleep apnea (OSA), however there is a lack of related literature in children with OSA. The main objective of this study was to explore the potential use of EPO as a pediatric OSA biomarker by exploring the relationship between serum EPO levels and the presence of pediatric OSA.

METHODS AND MATERIALS

A prospective study was conducted on children (4-12 years old) referred for overnight PSG. Thirty (30) consecutive children with mild. 30 consecutives with moderate, and 30 consecutives with severe OSA (OSA group), as well as 30 consecutive children with AHI≤1 (non-OSA group) were recruited. Morning blood specimens after PSG studies were obtained in order to compare EPO levels.

RESULTS

Finally, 115 children included for analysis. Non-OSA group consisted of 29 children (mean age: 6.93 ± 2.10) and OSA-group of 86 children (mean age: 6.78 ± 2.53). Mean EPO values for the non-OSA and OSA groups were 5.46 ± 2.29 mIU/ml and 8.33 ± 4.10 mIU/ml respectively. OSA-group had significant higher EPO levels than non-OSA (P: 0.01) while EPO levels were significantly correlated with AHI (p < 0.001).

CONCLUSION

Our study showed that serum EPO levels of children with OSA are significantly higher than those without OSA and correlate significantly with AHI. These results suggest that EPO may be considered as a biomarker candidate for pediatric OSA. Since this may be the first study on the topic further research is needed.

Much Ado about Sleep: Current Concepts on Mechanisms and Predisposition to Pediatric Obstructive Sleep Apnea

Obstructive Sleep Apnea (OSA) is a form of sleep-disordered breathing characterized by upper airway collapse during sleep resulting in recurring arousals and desaturations. However, many aspects of this syndrome in children remain unclear. Understanding underlying pathogenic mechanisms of OSA is critical for the development of therapeutic strategies. In this article, we review current concepts surrounding the mechanism, pathogenesis, and predisposing factors of pediatric OSA. Specifically, we discuss the biomechanical properties of the upper airway that contribute to its primary role in OSA pathogenesis and examine the anatomical and neuromuscular factors that predispose to upper airway narrowing and collapsibility.

Sleep Measurement in Children-Are We on the Right Track?

Sleep plays a critical role in the development of healthy children. Detecting sleep and sleep disorders and the effectiveness of interventions for improving sleep in children require valid sleep measures. Assessment of sleep in children, in particular infants and young children, can be a quite challenging task. Many subjective and objective methods are available to evaluate various aspects of sleep in childhood, each with their strengths and limitations. None can, however, replace the importance of thorough clinical interview with detailed history and clinical examination by a sleep specialist.

Artificial Neural Networks Analysis of polysomnographic and clinical features in Pediatric Acute-Onset Neuropsychiatric Syndrome (PANS): from sleep alteration to "Brain Fog"

STUDY OBJECTIVES

PANS (pediatric acute onset neuropsychiatric syndrome) is thought to be the result of several mechanisms and multiple etiologies, ranging from endocrine/metabolic causes to postinfectious autoimmune and neuroinflammatory disorders. Sleep disorders represent one of the most frequent manifestations of PANS, involving around 80% of patients. The present study describes the clinical and polysomnographic features in a group of PANS children identifying the relationships between sleep disorders and other PANS symptoms.

METHODS

All participants underwent a clinical evaluation including comprehensive sleep history, polysomnography, cognitive assessment and blood chemistry examination. A data mining approach with fourth-generation artificial neural networks has been used in order to discover subtle trends and associations among variables.

RESULTS

Polysomnography showed abnormality in 17 out of 23 recruited subjects (73.9%). In particular, 8/17 children (47%) had ineffective sleep, 10/17 (58.8%) fragmented sleep, 8/17 (47.1%) periodic limb movement disorder (PLMD) and 11/17 (64.7%) REM-sleep without atonia (RSWA). Most subjects presented more than one sleep disturbances. Notably, among the 19/23 patients diagnosed with Tic/Tourette disorder, 8/19 (42.1%) show PLMD and 10/19 (52.6%) RSWA. Artificial neural network methodology and the auto-contractive map exploited the links among the full spectrum of variables revealing the simultaneous connections among them, facing the complexity of PANS phenotype.

CONCLUSION

Disordered sleep represents, for prevalence and impact on quality of life, a cardinal symptom in patients with PANS. Thus, considering the weight of sleep disturbances on diagnosis and prognosis of PANS, we could consider the possibility of including them among the major diagnostic criteria.

Paediatrics: how to manage obstructive sleep apnoea syndrome

Obstructive sleep apnoea syndrome (OSAS) is defined as the intermittent reduction or cessation of airflow due to partial or complete obstruction of the upper airway during sleep. Paediatric OSAS has specific contributing factors, presenting symptoms and management strategies in various age groups. Untreated OSAS can lead to detrimental effects on neurocognitive development and cardiovascular and metabolic functions of a growing child. In the past decade, practice guidelines have been developed to guide the evaluation and management of OSAS. This article provides a narrative review on the current diagnostic and treatment options for paediatric OSAS. Alternative diagnostic tools other than the standard polysomnography are discussed. Adenotonsillectomy is considered the first-line therapy yet it is not suitable for treatment of all OSAS cases. Nocturnal non-invasive positive airway pressure ventilation is effective and could be the priority treatment for patients with complex comorbidities, residual OSAS post-adenotonsillectomy or obesity. However, intolerance and non-adherence are major challenges of positive airway pressure therapy especially in young children. There is increasing evidence for watchful waiting and other gentler alternative treatment options in mild OSAS. The role of anti-inflammatory drugs as the primary or adjunctive treatment is discussed. Other treatment options, including weight reduction, orthodontic procedures and myofunctional therapy, are indicated for selected patients. Nevertheless, the successful management of paediatric OSAS often requires a multidisciplinary team approach.

Research routes on improved sleep bruxism metrics: Toward a standardised approach

A recent report from the European Sleep Research Society's task force "Beyond AHI" discussed an issue that has been a long-term subject of debate - what are the best metrics for obstructive sleep apnoea (OSA) diagnosis and treatment outcome assessments? In a similar way, sleep bruxism (SB) metrics have also been a recurrent issue for >30 years and there is still uncertainty in dentistry regarding their optimisation and clinical relevance. SB can occur alone or with comorbidities such as OSA, gastroesophageal reflux disorder, insomnia, headache, orofacial pain, periodic limb movement, rapid eye movement behaviour disorder, and sleep epilepsy. Classically, the diagnosis of SB is based on the patient's dental and medical history and clinical manifestations; electromyography is used in research and for complex cases. The emergence of new technologies, such as sensors and artificial intelligence, has opened new opportunities. The main objective of the present review is to stimulate the creation of a collaborative taskforce on SB metrics. Several examples are available in sleep medicine. The development of more homogenised metrics could improve the accuracy and refinement of SB assessment, while moving forward toward a personalised approach. It is time to develop SB metrics that are relevant to clinical outcomes and benefit patients who suffer from one or more possible negative consequences of SB.

Effectiveness of Adenotonsillectomy vs Watchful Waiting in Young Children With Mild to Moderate Obstructive Sleep Apnea: A Randomized Clinical Trial

Importance

Adenotonsillectomy (ATE) is one of the most common surgical procedures to treat children with obstructive sleep apnea (OSA), but to our knowledge there are no randomized clinical trials confirming the benefit of surgery compared with watchful waiting in children between 2 and 4 years of age.

Objective

To determine whether ATE is more effective than watchful waiting for treating otherwise healthy children with mild to moderate OSA.

Design, Setting, and Participants

This randomized clinical trial was conducted from December 2014 to December 2017 at the Otorhinolaryngology Department of the Karolinska University Hospital, Stockholm, Sweden. A total of 60 children, 2 to 4 years of age, with an obstructive apnea-hypopnea index (OAHI) score of 2 or greater and less than 10, were randomized to ATE (n = 29) or watchful waiting (n = 31). A total of 53 participants (88%; ATE, n = 25; watchful waiting, n = 28) completed the study. Data were analyzed from August 2018 to December 2018.

Interventions

Adenotonsillectomy.

Main Outcomes and Measures

The primary outcome was the difference between the groups in mean OAHI score change. Secondary outcomes were other polysomnography parameters, score on the Obstructive Sleep Apnea-18 (OSA-18) questionnaire, and subgroup analyses. Polysomnography and the OSA-18 questionnaire were completed at baseline and after 6 months.

Results

Of the 60 included children, 34 (57%) were boys and the mean (SD) age at first polysomnography was 38 (9) months. Both groups had a decrease in mean OAHI score, and the difference in mean OAHI score change between the groups was small (-1.0; 95% CI, -2.4 to 0.5), in favor of ATE. However, there were large differences between the groups in favor of ATE regarding the OSA-18 questionnaire (eg, total OSA-18 score: -17; 95% CI, -24 to -10). Also, a subgroup analysis of 24 children with moderate OSA (OAHI ≥5 and <10) showed a meaningful difference in mean OAHI score change between the groups in favor of ATE (-3.1; 95% CI, -5.7 to -0.5). Of 28 children, 10 (36%) in the watchful waiting group received ATE after the follow-up, and 7 of these had moderate OSA at baseline.

Conclusions and Relevance

This randomized clinical trial found only small differences between the groups regarding changes in OAHI, but further studies are needed. However, there were large improvements in quality of life after ATE. These results suggest that otherwise healthy children with mild OSA and mild effect on quality of life may benefit from watchful waiting, while children with moderate OSA should be considered for ATE.

Trial Registration

ClinicalTrials.gov Identifier: NCT02315911.

Disease characteristics and neuropathological changes associated with cognitive dysfunction in obstructive sleep apnea

Obstructive sleep apnea (OSA) is a common sleep-disordered breathing disease that often leads to many comorbidities (e.g., cognitive dysfunction), which adversely affect the quality of life for patients with OSA. Thus far, the underlying mechanisms of this dysfunction remain unclear. Many studies have focused on OSA-related characteristics, including intermittent hypoxemia and sleep fragmentation. There is increasing emphasis on neuroimaging studies to explore underlying relationships between neuropathological changes and cognitive dysfunction. This article reviews recent research progress concerning cognitive dysfunction associated with OSA to reveal potential mechanisms that contribute to this dysfunction.

Validity and Cost-Effectiveness of Pediatric Home Respiratory Polygraphy for the Diagnosis of Obstructive Sleep Apnea in Children: Rationale, Study Design, and Methodology

Obstructive sleep apnea (OSA) in children is a prevalent, albeit largely undiagnosed disease associated with a large spectrum of morbidities. Overnight in-lab polysomnography remains the gold standard diagnostic approach, but is time-consuming, inconvenient, and expensive, and not readily available in many places. Simplified Home Respiratory Polygraphy (HRP) approaches have been proposed to reduce costs and facilitate the diagnostic process. However, evidence supporting the validity of HRP is still scarce, hampering its implementation in routine clinical use. The objectives were: Primary; to establish the diagnostic and therapeutic decision validity of a simplified HRP approach compared to PSG among children at risk of OSA. Secondary: (a) Analyze the cost-effectiveness of the HRP versus in-lab PSG in evaluation and treatment of pediatric OSA; (b) Evaluate the impact of therapeutic interventions based on HRP versus PSG findings six months after treatment using sleep and health parameters and quality of life instruments; (c) Discovery and validity of the urine biomarkers to establish the diagnosis of OSA and changes after treatment.

Metabolomics Analysis on Obesity-Related Obstructive Sleep Apnea After Weight Loss Management: A Preliminary Study

OBJECTIVE

Roux-en-Y gastric bypass (RYGB) surgery is an effective type of weight loss management and may improve obesity-related obstructive sleep apnea (OSA). Obese subjects who meet the criteria for surgery with OSA were enrolled. We investigated the metabolomic effects of RYGB on OSA.

METHODS

Clinical data, serum measurements including indices of glycolipid metabolism, and polysomnography (PSG) measurements were collected at baseline and 6 months after RYGB surgery. Metabolomic analysis was performed using ultra-performance liquid chromatography-mass spectrometry.

RESULTS

A group of 37 patients with obesity, type 2 diabetes (T2DM) and suspected OSA were enrolled of which 27 were OSA subjects. After RYGB surgery, metabolic outcomes and sleep parameters were all significantly improved. The OSA remission group had lower valine, isoleucine, and C24:1(cis-15) levels, and higher trimethylamine N-oxide, hippurate, and indole-3-propionic acid levels after RYGB surgery. A combination of preoperative indices (age, apnea-hypopnea index (AHI), fasting C-peptide level, and hippurate level) predicted the RYGB effect size in obese patients with T2DM and OSA, with an area under receiver operating characteristic curve of 0.947, specificity of 82.4%, and sensitivity of 100%.

CONCLUSIONS

RYGB surgery may significantly improve the metabolic status of patients with obesity, T2DM and OSA. A combination of preoperative indices (age, AHI, fasting C peptide level, and hippurate level) may be useful for predicting the effect size of RYGB in obese patients with T2DM and OSA. The mechanisms underlying OSA remission need to be explored.

The efficacy and safety of montelukast in children with obstructive sleep apnea: a systematic review and meta-analysis

OBJECTIVE

The efficacy and safety of montelukast in children with obstructive sleep apnea (OSA) remain controversial. Therefore, the aims of this systemic review and meta-analysis are to verify this issue and further provide reference for clinical practice.

METHODS

Seven databases were searched for randomized controlled trials (RCTs) up to September 30, 2019. The literature screening and data extraction were performed by two independent researchers. Adverse reactions from trials were also recorded. Meta-analysis was performed and analyzed heterogeneity. Methodological and evidence quality were followed by to evaluate according to Cochrane handbook.

RESULTS

A total of 4 RCTs including 305 children with mild to moderate OSA were involved. Compared with placebo, we found that oral montelukast (OM) significantly improved polysomnography (PSG) monitoring parameters, typical and relevant symptoms including snoring and mouth breathing, and adenoid morphology in children with OSA. When compared with routine drugs, not only PSG monitoring parameters and adenoid morphology, but also sleep-disordered breathing (SDB)-related questionnaire scores were improved in patients with OSA treated by combination of OM and routine drugs. In addition, compared with single nasal spray of mometasone furoate, the present study also showed that OM combined with nasal spray of mometasone furoate significantly improved PSG monitoring parameters, symptoms of snoring and mouth breathing and reduced tonsil morphology in pediatric OSA. In terms of treatment safety, one study reported adverse reactions of OM such as headache, nausea and vomiting, while no adverse events were reported after OM treatment in another study.

CONCLUSION

As a classic leukotriene receptor antagonist, montelukast can be used to treat children with mild to moderate OSA in the short term and improve clinical characteristics. The promotion and application of OM in clinic is considered to be a noninvasive option to avoid surgical treatment.

Journey towards a personalised medicine approach for OSA: Can a similar approach to adult OSA be applied to paediatric OSA?

The concept of personalised medicine is likely to revolutionise the treatment of adult obstructive sleep apnoea as a result of recent advances in the understanding of disease heterogeneity by identifying clinical phenotypes, pathophysiological endotypes, biomarkers and treatable traits. Children with the condition show a similar level of heterogeneity and paediatric obstructive sleep apnoea would also benefit from a more targeted approach to diagnosis and management. This review aims to summarise the adult literature on the phenotypes and endotypes of obstructive sleep apnoea and assess whether a similar approach may also be suitable to guide the development of new diagnostic and management approaches for paediatric obstructive sleep apnoea.

Advances and challenges in pursuing biomarkers for obstructive sleep apnea: Implications for the cardiovascular risk

Obstructive sleep apnea (OSA) is a common clinical condition associated with increased cardiovascular morbidity and mortality. Recent evidence from clinical studies and animal models suggest that OSA can promote cardiovascular disease by inducing autonomic, hemodynamic, inflammatory and metabolic dysregulation. However, most of the evidence addressing hard endpoints in humans is derived from observational studies. Several challenges have been noted in the pursuit of a comprehensive knowledge base about the impact of OSA including: 1) the precise mechanisms by which OSA causes metabolic and cardiovascular consequences are not clear, which limits our current ability to address potential targets in OSA; 2) several patients with OSA, even with severe forms, present with no or mild daytime symptoms. Beyond the obvious challenges for obtaining good adherence for conventional OSA treatments, there is evidence that symptomatic vs. asymptomatic patients with OSA do not necessarily have the same metabolic and cardiovascular outcomes; and 3) the cardiovascular response to OSA treatment may vary even in those patients with good adherence. In this scenario, there is an obvious need to develop biomarkers in the OSA research area. This review focuses on describing the advances that have occurred so far in exploring potential OSA biomarkers with clear emphasis for the cardiovascular risk. Particular attention will be devoted to discuss molecular biomarkers including the potential role of microRNAs, proteomics and metabolomics. We also discuss the major challenges and perspectives in this growing research field.

Accuracy of clinical scoring tools for the diagnosis of pediatric obstructive sleep apnea

OBJECTIVES

To assess the diagnostic test accuracy of questionnaire and clinical examination-based scoring tools in the diagnosis of pediatric obstructive sleep apnea (OSA).

METHODS

A comprehensive literature search was performed to identify studies published from 1960 to 2018 that evaluated the accuracy of clinical scoring tools in the diagnosis of pediatric OSA. Studies that did not include attended polysomnography as a reference standard were excluded. The study populations were children under 18 years old without craniofacial abnormalities, congenital syndromes, or other complex medical conditions. Outcomes measures were diagnostic test accuracy (DTA) statistics including sensitivity, specificity, and area under the curve (AUC) from receiver operating characteristic curve analysis.

RESULTS

Fifteen different scoring tools were identified. Authors chose different polysomnographic criteria to diagnose OSA. Four of the tools had undergone multiple DTA studies by different authors (OSA Score, Sleep-Related Breathing Disorder [SRBD] scale, Severity Score, and OSA-18). The Pediatric Sleep Questionnaire SRBD scale, which is widely used, has a sensitivity of 71% to 84% in included studies, but specificity as low as 13% and a low AUC of 0.57-0.69, indicating poor diagnostic accuracy. None of the 15 scoring tools performed well enough to be considered accurate diagnostic tests for pediatric OSA.

CONCLUSIONS

A well-designed questionnaire can provide crucial information on the impact of sleep-disordered breathing on a child's physical and psychological health, which may not be adequately reflected in objective polysomnography outcomes measures. However, DTA results indicate that published clinical scoring tools do not accurately predict a diagnosis of pediatric OSA as defined by polysomnography outcome measures. Laryngoscope, 130:1034-1043, 2020.

Guidelines of the French Society of Otorhinolaryngology. Role of the ENT specialist in the diagnosis of obstructive sleep apnea-hypopnea syndrome (OSAHS) in children. Part 2: Diagnostic investigations apart from sleep studies

OBJECTIVES

To present the 2017 Clinical Practice Guidelines of the French Society of Otorhinolaryngology concerning the role of the ENT specialist in the diagnosis of pediatric obstructive sleep apnea-hypopnea syndrome. This manuscript specifically focuses on diagnostic investigations apart from sleep studies.

METHODS

A multidisciplinary work-group drew up a first version of the guidelines, graded according to level of evidence following the GRADE grading system. The final version was obtained by including the suggestions and comments from the editorial group.

RESULTS

At the end of the process, guidelines were established and graded regarding diagnostic investigations apart from sleep studies, in particular respiratory functional tests, biological markers, and morphologic assessment under induced sleep (drug-induced sleep endoscopy (DISE) and cine-MRI).

Preschoolers with recurrent wheezing have a high prevalence of sleep disordered breathing

Objective: Sleep-disordered breathing (SDB) is highly prevalent in school children with poorly-controlled asthma. However, this association has not been assessed in preschoolers with recurrent wheeze, nor in those at risk for asthma. We hypothesized that preschoolers with asthma risk (positive asthma predictive index [API]) have a higher prevalence of SDB and higher inflammatory biomarkers (blood-hsCRP and urinary-LTE4) levels than those with negative API.Method: Children 2 to 5 years of age with recurrent wheezing were classified as positive or negative API. SDB was determined by the pediatric sleep questionnaire (PSQ) and its subscale (PSQSub6). Demographic characteristics, spirometry, blood hsCRP and urinary LTE4 were assessed.Results: We enrolled 101 preschoolers: 70 completed all measurements, 55.4% were males, mean age 4.07 ± 0.87 years, 45% overweight or obese, 70% had positive API, 87.5% had rhinitis. The prevalence of SDB measured by PSQ was 40.8% and by PSQSub6 was 29.6%. However, the proportion of SDB was similar between positive and negative API groups. The hsCRP (mean ± SD) was higher in the positive than in negative API (3.58 ± 0.58 and 1.32 ± 0.36 mg/L, p = 0.69, respectively); moreover, no differences in urinary LTE4 were found between groups. No correlation of PSQ (+) or PSQSub6 (+) with hsCRP and uLTE4 was found. However, preschoolers with positive API had significantly more post-bronchodilator percentage change in FEF25-75 than negative API (24.14 ± 28.1 vs. 4.13 ± 21.8, respectively, p = 0.01).Conclusions: In preschoolers with recurrent wheezing, we should be investigating for the coexistence of SDB, using early screening methods for detecting those conditions.

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.

Related biomarkers of neurocognitive impairment in children with obstructive sleep apnea

OBJECTIVES

Different experiment approaches have demonstrated that children with obstructive sleep apnea (OSA) exhibit neurocognitive and behavioral deficits. This review summarized the potential biomarkers of OSA-associated neurocognitive impairment in children.

METHODS

A scoping review of studies on children with OSA that evaluated the potential value of different markers in identifying neurocognitive impairment was undertaken. Additionally, the biomarkers were categorized according to the different research methods, including brain imaging studies, serological indicators and urine markers.

RESULTS

Majority of the studies that evaluated blood biomarkers, plasma insulin growth factor-1 (IGF-1) and Alzheimer's disease (AD)-related biomarkers appeared to exhibit a favorable profile, and could discriminate between OSA children with or without neurocognitive impairments. Brain imaging studies and urinary neurotransmitters could also be helpful for screening OSA cognitive morbidity in children.

CONCLUSION

Due to limited research methods available in children, the cognitive susceptibility of children with OSA has been rarely studied. The main reason for this may be the limited research methods in children. Numerous study populations of children and complex psychological tests are required, which involve major labor and costs.Multi-center prospective studies are needed to identify suitable biomarkers for the timely prediction and effective intervention to prevent neurocognitive impairment in children with OSA and to explore further opportunities in this arena.

Metabolomic and lipidomic profile in men with obstructive sleep apnoea: implications for diagnosis and biomarkers of cardiovascular risk

The use of metabolomic and lipidomic strategies for selecting potential biomarkers for obstructive sleep apnoea (OSA) has been little explored. We examined adult male patients with OSA (defined by an apnoea-hypopnoea index ≥15 events/hour), as well as age-, gender-, and fat-composition-matched volunteers without OSA. All subjects were subjected to clinical evaluation, sleep questionnaires for detecting the risk of OSA (Berlin and NoSAS score), metabolomic analysis by gas chromatography coupled to mass spectrometry and lipidomic analysis with liquid chromatography followed by detection by MALDI-MS. This study included 37 patients with OSA and 16 controls. From the 6 metabolites and 22 lipids initially selected, those with the best association with OSA were glutamic acid, deoxy sugar and arachidonic acid (metabolites), and glycerophosphoethanolamines, sphingomyelin and lyso-phosphocholines (lipids). For the questionnaires, the NoSAS score performed best with screening for OSA (area under the curve [AUC] = 0.724, p = 0.003). The combination of the NoSAS score with metabolites or lipids resulted in an AUC for detecting OSA of 0.911 and 0.951, respectively. In conclusion, metabolomic and lipidomic strategies suggested potential early biomarkers in OSA that could also be helpful in screening for this sleep disorder beyond traditional questionnaires.

Regional brain tissue integrity in pediatric obstructive sleep apnea

Children with long-standing obstructive sleep apnea (OSA) show evidence of neural injury and functional deficits in behavioral and cognitive regulatory brain regions that are reflected in symptoms of altered cognitive performance and behaviors. While we earlier showed reduced gray matter volume and increased and reduced regional cortical thicknesses, such structural changes give little indication of the underlying pathology. Brain tissue integrity in pediatric OSA subjects can reflect the nature and extent of injury or structural adaptation, and can be assessed by entropy tissue texture, a measure of local changes in signal intensity patterns from high-resolution magnetic resonance images. We collected high-resolution T1-weighted magnetic resonance images from 10 pediatric OSA (age, 7.9 ± 1.1 years; apnea-hypopnea-index, 8.8 ± 3.0 events/hour; body-mass-index, 20 ± 6.7 kg/m²; 7 male) and 8 healthy controls (age, 8.8 ± 1.6 years; body-mass-index, 19.6 ± 5.9 kg/m²; 5 female). Images were bias-corrected and entropy maps calculated, individual maps were normalized to a common space, smoothed, and compared between groups (ANCOVA; covariates: age, gender; SPM12, uncorrected-threshold p < 0.005). No significant differences in age (p = .48), gender (p = .59), or body-mass-index (p = .63) emerged between groups. In OSA children, several brain sites including the pre-frontal cortex, middle and posterior corpus callosum, thalamus, hippocampus, and cerebellar areas showed reduced entropy values, indicating tissue changes suggestive of acute insults. No regions showed higher entropy values in OSA. Children suffering from OSA display predominantly acute tissue injury in neural regions principally localized within autonomic, respiratory, cognitive, and neuropsychologic control, functions that correspond to previously-reported comorbidities associated with OSA. A range of acute processes, including hypoxia/re-oxygenation, repeated arousals, and episodic hypercarbia, may have contributed to regional brain tissue integrity changes in pediatric OSA.

Sleep Apnea Morbidity: A Consequence of Microbial-Immune Cross-Talk?

OSA has emerged as a highly prevalent public health problem that imposes important mid- and long-term consequences, namely cardiovascular, metabolic, cognitive, and cancer-related alterations. OSA is characterized by increased upper airway resistance, alveolar hypoventilation, and recurrent upper airway obstruction during sleep. Recurrent collapse of the upper airway develops with sleep onset and is associated with both intermittent hypoxemia and sleep fragmentation. The microbiome is a vast and complex polymicrobial ecosystem that coexists with the human organism, and it has been identified as playing significant roles in the development of host immunologic phenotypes. In humans and animal models, changes in gut microbial communities occur with lifestyle behaviors, such as smoking, long-distance travel, dietary preferences, physical exercise, and circadian rhythm disturbances. In parallel, diseases previously attributed in part to lifestyle such as obesity, coronary heart disease, depression, and asthma (also associated with OSA) are now claimed as microbiota related. We therefore posit that altered patterns of sleep and oxygenation, as seen in OSA, will promote specific alterations in gut microbiota that in turn will elicit the immunologic alterations that lead to OSA-induced end-organ morbidities. The present article assesses the potential mechanistic links between OSA-induced changes in gut microbiota and its morbid phenotypes.

DNA Methylation in Pediatric Obstructive Sleep Apnea: An Overview of Preliminary Findings

Obstructive sleep apnea (OSA) is characterized by phenotypic variations, which can be partly attributed to specific gene polymorphisms. Recent studies have focused on the role of epigenetic mechanisms in order to permit a more precise perception about clinical phenotyping and targeted therapies. The aim of this review was to synthesize the current state of knowledge on the relation between DNA methylation patterns and the development of pediatric OSA, in light of the apparent limited literature in the field. We performed an electronic search in PubMed, EMBASE, and Google Scholar databases, including all types of articles written in English until January 2017. Literature was apparently scarce; only 2 studies on pediatric populations and 3 animal studies were identified. Forkhead Box P3 (FOXP3) DNA methylation levels were associated with inflammatory biomarkers and serum lipids. Hypermethylation of the core promoter region of endothelial Nitric Oxide Synthase (eNOS) gene in OSA children were related with decreased eNOS expression. Additionally, increased expression of genes encoding pro-oxidant enzymes and decreased expression of genes encoding anti-oxidant enzymes suggested that disturbances in oxygen homeostasis throughout neonatal period predetermined increased hypoxic sensing in adulthood. In conclusion, epigenetic modifications may be crucial in pediatric sleep disorders to enable in-depth understanding of genotype-phenotype interactions and lead to risk assessment. Epigenome-wide association studies are urgently needed to validate certain epigenetic alterations as reliable, novel biomarkers for the molecular prognosis and diagnosis of OSA patients with high risk of end-organ morbidity.

Personalised medicine in sleep respiratory disorders: focus on obstructive sleep apnoea diagnosis and treatment

In all fields of medicine, major efforts are currently dedicated to improve the clinical, physiological and therapeutic understanding of disease, and obstructive sleep apnoea (OSA) is no exception. The personalised medicine approach is relevant for OSA, given its complex pathophysiology and variable clinical presentation, the interactions with comorbid conditions and its possible contribution to poor outcomes. Treatment with continuous positive airway pressure (CPAP) is effective, but CPAP is poorly tolerated or not accepted in a considerable proportion of OSA patients. This review summarises the available studies on the physiological phenotypes of upper airway response to obstruction during sleep, and the clinical presentations of OSA (phenotypes and clusters) with a special focus on our changing attitudes towards approaches to treatment. Such major efforts are likely to change and expand treatment options for OSA beyond the most common current choices (i.e CPAP, mandibular advancement devices, positional treatment, lifestyle changes or upper airway surgery). More importantly, treatment for OSA may become more effective, being tailored to each patient's need.

Obstructive sleep apnea: in search of precision

Introduction

Obstructive sleep apnea (OSA) is a highly prevalent condition that is viewed as a major global health concern, while affecting approximately 10% of the middle-aged population. OSA is a chronic disease that has been conclusively associated with poor quality of life, cognitive impairments and mood alterations, enhanced cardiovascular and metabolic morbidity, thereby leading to marked increments in healthcare costs.

Areas covered

The authors have reviewed the current evidence on the pathophysiology of OSA and its consequences, the heterogeneity of its phenotypic expression, the current therapeutic applications and their efficacy, and the implications for diagnosis, treatment and follow-up strategies in the context of the clinical management of OSA.

Expert commentary

Personalized medicine in OSA identifies different needs and approaches: i) phenotyping and defining the different and segregated clusters of OSA patients whose recognition may improve prognostic predictions and guide therapeutic strategies; ii) to further characterize and predict the impact of OSA and its treatment, particularly revolving around mortality and the processes closely related to ageing (cardiovascular diseases, cancer and neurocognitive diseases); iii) the introduction of new technologies including telemedicine that have shown promise in the implementation of personalized medicine approaches.

Glycated hemoglobin and sleep apnea syndrome in children: beyond the apnea-hypopnea index

PURPOSE

Snoring and obstructive sleep apnea syndrome (OSA) are frequent conditions in pediatrics. Glycated hemoglobin (Hb_A1C) is a useful homeostatic biomarker of glycemia and may reflect alterations deriving from sleep breathing disorders. The aim of this study was to relate the severity of OSA with blood Hb_A1C levels in children.

METHODS

A descriptive observational study in snoring patients was performed. All patients underwent a sleep study and classified either as simple snorers (apnea-hypopnea index; AHI ≤ 1 episodies/h) or as OSA patients (AHI > 1 episodes/h). In the following morning, a blood glycemic profile (fasting glucose, insulin, Hb_A1C, and the HOMA index) was performed to every individual.

RESULTS

A total of 48 patients were included. Hb_A1C levels were shown to be increased in the moderate OSA (AHI > 5 episodes/h) group (5.05 ± 0.25 vs. 5.24 ± 0.29%; p = 0.019). Significant correlations were found between Hb_A1C values and AHI (r = 0.345; p = 0.016) and also with oxygen desaturation index (r = 0.40; p = 0.005). Correlations remained significant after adjusting by age and body mass index. The AHI-associated change in Hb_A1C was 13.4% (p = 0.011).

CONCLUSIONS

In the pediatric population, Hb_A1C is a biomarker associated with OSA severity, and this relationship is age- and obesity-independent. The fact that this association was observed in snoring patients could help the physician in the distinction between those patients affected with OSA and those with simple snoring. Therefore, Hb_A1C measurement could play a major role in the diagnosis and the management of the syndrome.