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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.

Introduction: Tissue hypoxia stimulates the production of erythropoietin (EPO), the main effect of which is, in turn, to stimulate erythropoiesis. Sleep apnea-hypopnea syndrome (SAHS) is an entity characterized by repeated episodes of hypoxemia during sleep., Objective: To analyze whether hypoxemia stimulated increased urinary excretion of EPO, and if so, to evaluate if treatment with continuous positive airway pressure (CPAP) can inhibit this phenomenon., Methods: We studied 25 subjects with suspected SAHS who underwent a polysomnography study (PSG). EPO levels in first morning urine (uEPO) and blood creatinine and hemoglobin were determined in all patients. Patients with severe SAHS repeated the same determinations after CPAP treatment., Results: Twelve subjects were diagnosed with severe SAHS (mean ± SD, AHI 53.1 ± 22.7). Creatinine and hemoglobin levels were normal in all subjects. uEPO was 4 times higher in the SAHS group than in the control group (1.32 ± 0.83 vs. 0.32 ± 0.35 UI/l, p <.002). CPAP treatment reduced uEPO to 0.61 ± 0.9 UI/l (p <.02), levels close to those observed in healthy subjects. No dose-response relationship was observed between severity of PSG changes and uEPO values., Conclusions: Patients with severe SAHS show increased uEPO excretion, but this normalizes after treatment with CPAP., (Copyright © 2017 SEPAR. Publicado por Elsevier España, S.L.U. All rights reserved.)

Objective Due to limitations of polysomnography (PSG), novel ways to evaluate pediatric obstructive sleep apnea (OSA) are needed. Urinary leukotriene E4 (LTE4), an inflammatory marker, has been identified as a potential biomarker for pediatric OSA. The objective of the study was to assess whether urinary LTE4 levels correlate with OSA severity, as determined by obstructive apnea-hypopnea index (AHI) and nadir oxygen saturation. Study Design Prospective trial. Setting Tertiary care children's hospital. Subjects and Methods Children (age, 3-16 years) with sleep-disordered breathing (SDB) who were referred for PSG were included. Urine samples were obtained the morning following PSG, and urinary LTE4 levels were quantified with enzyme-linked immunoassay kits. Results A total of 113 children were enrolled, and the mean age was 7.3 years. Thirty-nine percent (n = 44) were obese, and the majority were white (53%, n = 58). Seventy-eight percent (n = 88) were diagnosed with OSA (AHI >1), with 27% (n = 30) having severe disease (AHI >10). The mean urinary LTE4 level was 91.3 ng/mM. Urinary LTE4 levels did not correlate with AHI ( P = .77) or nadir oxygen saturation ( P = .64). There was a significant difference in urinary LTE4 levels between patients with mild SDB and those with moderate to severe OSA ( P = .03). Conclusion Urinary LTE4 levels do not correlate with AHI in children with SDB. Compared with children with severe OSA, children with mild SDB have higher urinary LTE4 levels. Further research is needed determine whether urinary LTE4 is a satisfactory biomarker for pediatric OSA.

Background: The lysosomal storage disorder, mucopolysaccharidosis I (MPS I), commonly manifests with upper airway obstruction and sleep disordered breathing (SDB). The success of current therapies, including haematopoietic stem cell transplantation (HSCT) and enzyme replacement therapy (ERT) may be influenced by a number of factors and monitored using biomarkers of metabolic correction. We describe the pattern of SDB seen in the largest MPS I cohort described to date and determine therapies and biomarkers influencing the severity of long-term airway disease., Methods: Therapeutic, clinical and biomarker data, including longitudinal outcome parameters from 150 sleep oximetry studies were collected in 61 MPS I (44 Hurler, 17 attenuated) patients between 6 months pre to 16 years post-treatment (median follow-up 22 months). The presence and functional nature of an immune response to ERT was determined using ELISA and a cellular uptake inhibition assay. Multivariate analysis was performed to determine significant correlators of airway disease., Results: The incidence of SDB in our cohort is 68%, while 16% require therapeutic intervention for airway obstruction. A greater rate of progression (73%) and requirement for intervention is seen amongst ERT patients in contrast to HSCT treated individuals (24%). Multivariate analysis identifies poorer metabolic clearance, as measured by a rise in the biomarker urinary dermatan sulphate: chondroitin sulphate (DS:CS) ratio, as a significant correlator of increased presence and severity of SDB in MPS I patients (p = 0.0017, 0.008). Amongst transplanted Hurler patients, delivered enzyme (leukocyte iduronidase) at one year is significantly raised in those without SDB (p = 0.004). Cellular uptake inhibitory antibodies in ERT treated patients correlate with reduced substrate clearance and occurrence of severe SDB (p = 0.001)., Conclusion: We have identified biochemical and therapeutic factors modifying airway disease across the phenotypic spectrum in MPS I. Interventions maximising substrate reduction correlate with improved long-term SDB, while inhibitory antibodies impact on biochemical and clinical outcomes. Monitoring and tolerisation strategies should be re-evaluated to improve detection and minimise the inhibitory antibody response to ERT in MPS I and other lysosomal storage diseases. Future studies should consider the use of sleep disordered breathing as an objective parameter of clinical and metabolic improvement.