Obstructive sleep apnea and obesity are associated with reduced GPR 120 plasma levels in children.
BACKGROUND
Obstructive sleep apnea (OSA) is a common health problem, particularly in obese children, in whom a vicious cycle of obesity and OSA interdependencies promotes increased food intake. G protein-coupled receptor 120 (GPR 120) is a long-chain free fatty acid (FFA) receptor that plays an important role in energy homeostasis, and protects against insulin resistance and systemic inflammation. We hypothesized that GPR 120 levels would be reduced in children with OSA, particularly among obese children.


METHODS
Cross-sectional prospectively recruited cohort.


METHODS
Academic pediatric sleep program.


METHODS
Two hundred twenty-six children (mean age: 7.0 ± 2.1 y) underwent overnight polysomnographic evaluation and a fasting blood draw the morning after the sleep study. In addition to lipid profile, homeostasis model assessment of insulin resistance (HOMA-IR) and high-sensitivity C-reactive protein (hsCRP) assays, monocyte GPR 120 expression, and plasma GPR 120 levels were assessed using quantitative polymerase chain reaction and enzyme-linked immunosorbent assay kits.


RESULTS
Obese children and those with OSA had significantly lower GPR 120 monocyte expression and plasma GPR 120 levels. Furthermore, when both obesity and OSA were present, GPR 120 levels were lowest. Linear associations emerged between GPR 120 plasma levels and body mass index (BMI) z score, as well as with apnea-hypopnea index (AHI), saturation of peripheral oxygen (SpO2) nadir, and respiratory arousal index (RAI), with RAI remaining statistically significant when controlling for age, ethnicity, sex, and BMI z score (P < 0.001). Similarly, HOMA-IR was significantly associated with GPR 120 levels, but neither low density lipoprotein nor high density lipoprotein cholesterol or hsCRP levels exhibited significant correlations.


CONCLUSIONS
G protein-coupled receptor 120 (GPR 120) levels are reduced in pediatric OSA and obesity (particularly when both are present) and may play a role in modulating the degree of insulin resistance. The short- and long-term significance of reduced GPR 120 relative to food intake and glycemic deregulation remains undefined.
Section of Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL.
David
D
Gozal
Section of Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL.
Leila
L
Kheirandish-Gozal
Section of Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL.
Alba
A
Carreras
Section of Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL.
Abdelnaby
A
Khalyfa
Section of Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL.
Eduard
E
Peris
D015992:Body Mass Index; D002097:C-Reactive Protein / Q000032:analysis; D002648:Child; D003430:Cross-Sectional Studies; D005215:Fasting; D005260:Female; D006706:Homeostasis; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D008055:Lipids / Q000097:blood; D008297:Male; D009000:Monocytes / Q000378:metabolism; D009765:Obesity / Q000097:blood* / Q000150:complications* / Q000235:genetics; D017286:Polysomnography; D043562:Receptors, G-Protein-Coupled / Q000097:blood* / Q000235:genetics; D012890:Sleep / Q000502:physiology; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000150:complications* / Q000235:genetics
C519853:FFAR4 protein, human; D008055:Lipids; D043562:Receptors, G-Protein-Coupled; D002097:C-Reactive Protein
inflammation; insulin resistance; lipid profile; obesity; obstructive sleep apnea