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Background: In obstructive sleep apnea (OSA), intermittent hypoxemia and intrathoracic pressure fluctuations may increase atrial fibrillation (AF) susceptibility by cholinergic activation., Objective: To investigate short-term atrial electrophysiological consequences of obstructive respiratory events, simulated by intermittent negative upper airway pressure (INAP), and the role of atrial acetylcholine-regulated potassium current ( I K,ACh ) activated by the M 2 receptor., Methods: In sedated (2% isoflurane), spontaneously breathing rats, INAP was applied noninvasively by a negative pressure device for 1 minute, followed by a resting period of 4 minutes. INAP was applied repeatedly throughout 70 minutes, followed by a 2-hour recovery period. Atrial effective refractory period (AERP) and AF inducibility were determined throughout the protocol. To study INAP-induced I K,ACh activation, protein levels of protein kinase C (PKC Ɛ ) were determined in membrane and cytosolic fractions of left atrial (LA) tissue by Western blotting. Moreover, an I K,ACh inhibitor (XAF-1407: 1 mg/kg) and a muscarinic receptor inhibitor (atropine: 1 μg/kg) were investigated., Results: In vehicle-treated rats, repetitive INAP shortened AERP (37 ± 3 ms vs baseline 44 ± 3 ms; P = .001) and increased LA membrane PKC Ɛ content relative to cytosolic levels. Upon INAP recovery, ratio of PKC Ɛ membrane to cytosol content normalized and INAP-induced AERP shortening reversed. Both XAF-1407 and atropine increased baseline AERP (control vs XAF-1407: 61 ± 4 ms; P > .001 and control vs atropine: 58 ± 3 ms; P = .011) and abolished INAP-associated AERP shortening., Conclusion: Short-term simulated OSA is associated with a progressive, but transient, AERP shortening and a PKC Ɛ translocation to LA membrane. Pharmacological I K,ACh and muscarinic receptor inhibition prevented transient INAP-induced AERP shortening, suggesting an involvement of I K,ACh in the transient arrhythmogenic AF substrate in OSA., (© 2021 Heart Rhythm Society. Published by Elsevier Inc.)

Background and Aims: Pediatric obesity associates with both low-grade inflammation and cardiometabolic risk on the population level. Yet on an individual patient level, overweight/obesity does not always equal increased cardiometabolic risk. In this study, we examine whether low-grade inflammation associates with cardiometabolic risk in Danish children, independent of degree of adiposity. We further assess the value of integrating multiple inflammation markers to identify children with very-high cardiometabolic risk profiles., Method and Results: We studied 2192 children and adolescents aged 6-18 years from an obesity clinic cohort and a population-based cohort, in a cross-sectional study design. Anthropometry, blood pressure, pubertal stage and body composition by dual-energy X-ray absorptiometry were assessed, and biomarkers including fasting serum high sensitivity C-reactive protein (hsCRP), white blood cells (WBC), resistin, lipid profile and glucose metabolism were measured. Adjusted correlation analysis and odds ratios were calculated. We found that, independent of degree of adiposity, having high-normal inflammation marker concentrations associated with increased cardiometabolic risk: for girls, hsCRP >0.57-9.98 mg/L (mid/upper tertile) associated with ~2-fold higher odds of dyslipidemia and hepatic steatosis (vs. lower tertile). For both sexes, WBC >7.0-12.4 10 9 /L (upper tertile) associated with 2.5-fold higher odds of insulin resistance. Lastly, children with multiple inflammation markers in the high-normal range exhibited the most severe cardiometabolic risk profile., Conclusion: Low-grade inflammation associates with cardiometabolic risk in children independent of degree of adiposity. The associations vary with sex and inflammation marker measured. Finally, integrating multiple low-grade inflammation markers identifies a very-high-risk subgroup of children with overweight/obesity and may have clinical value., Competing Interests: Declaration of Competing Interest JH received lecture fees from Novo Nordisk and is the owner of Dr Holm Ltd, which provides medical services, training and supervision. All other authors have nothing to disclose., (Copyright © 2020 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.)