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Objective: To assess the association of sleep disorders with the findings of heart rate variability (HRV) in children and adolescents with cystic fibrosis (CF)., Methods: Cross-sectional study including children and adolescents aged six to 18 years with a clinical diagnosis of CF. Sociodemographic and clinical data were collected. Sleep disorders were evaluated using baseline nocturnal polysomnography. The autonomic nervous system (ANS) was evaluated through resting HRV., Results: A total of 30 individuals (11.2 years) with a mean forced expiratory volume in the first second (FEV1) of 62.7% were included. The respiratory disturbance index presented a median of 2.6 and obstructive sleep apnea syndrome (OSAS) was identified in 30%. In the HRV analysis, a mean standard deviation of all inter-beat (RR) intervals (SDNN) of 60.8±45.9ms was found. There was a significant correlation between the HRV low-frequency/high-frequency (LF/HF) global modulation index and the minimum SpO2 during sleep in patients with FEV1<60% (r=0.71; p=0.02). The prevalence of sleep disorders and HRV abnormalities was higher in individuals with lesser pulmonary function (FEV1<60%)., Conclusions: The results indicate a weak correlation of sleep disorders (minimum SpO2) with HRV parameters (LH/HF) in children and adolescents with CF. When pulmonary function was reduced, a stronger correlation was found, highlighting the influence of disease severity. A high prevalence of ANS disorders, nocturnal hypoxemia, and presence of OSAS was also found.

Objective: To evaluate the presence of sleep disorders and its associations with exercise capacity and daily physical activity levels among children and adolescents with CF., Methods: Children age 6-18 years with a diagnosis of CF were recruited. Information regarding sociodemographic profile, pulmonary function and nutritional status were collected. Sleep disorders (polysomnography), exercise capacity (modified shuttle test - MST) and daily physical activity levels (questionnaire and five days accelerometer use) were evaluated., Results: Thirty-one patients, median age of 9.6 years and forced expiratory volume in 1 s (FEV 1 ) of 68.1 ± 24.4%, were included. Obstructive sleep apnea syndrome (OSAS) was present in 32.3% and nocturnal hypoxemia in 29%. The MST distance correlated with the mean peripheral oxyhemoglobin saturation (SpO 2 ) during sleep (r = 0.40) and the percent of total sleep time with SpO 2 <90% (r = -0.49). The final MST SpO 2 correlated with the occurrence of OSAS (r = -0.48) and mean nocturnal SpO 2 (r = 0.45). Sedentary activities, as measured by accelerometry, correlated with sleep architecture, including the percent of stage II (r = 0.60) and rapid eye movement (REM) stage sleep (r = -0.37). Patients with OSAS and nocturnal hypoxemia presented lower values (p < 0.05) of distance and final SpO 2 in the MST. Nocturnal hypoxemia was the main variable to influence exercise capacity (r 2  = 0.521)., Conclusion: Sleep disorders are distinctively related with exercise capacity and daily physical activity levels, as nocturnal hypoxemia is associated with exercise intolerance and sleep architecture disorders are associated with sedentary physical activity levels., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Major depression (MD) is an independent cardiovascular risk factor, but the exact mechanisms are not clear. In this study we have investigated the intraplatelet L-arginine-nitric oxide (NO) pathway and platelet function in depressive patients., Methods: Nineteen unmedicated patients with MD (34±4years) and 19 control subjects (CS, 34±3years) were included. L-[(3)H]-arginine influx, NO synthase (NOS) activity and intracellular cGMP levels were evaluated in platelets, as well as the expression of eNOS, iNOS, arginase and soluble guanylate cyclase (sGC), platelet aggregation and the systemic amino acid profile in MD patients and CS., Results: L-arginine influx (pmol/10(9)cells/min) in platelets was reduced from 46.2±9.5 to 20.02±2.12 in depression. NOS activity (pmol/10(8) cells) was diminished in MD patients (0.09±0.01) compared to CS (0.17±0.01). Intracellular cGMP levels were also impaired in MD patients associated with hyperaggregability. Moreover, the concentration of plasma L-arginine was reduced by 20% in MD patients. The expression of eNOS, iNOS, arginase II and sGC in platelet lysates was not affected by MD., Limitations: Small number of patients in the study., Conclusions: This study has demonstrated an impairment of L-arginine-NO signaling in platelets from MD patients, suggesting a role in platelet activation and cardiovascular events., (Copyright © 2012 Elsevier B.V. All rights reserved.)