NREM sleep architecture and relation to GH/IGF-1 axis in Laron syndrome.
BACKGROUND
Laron syndrome (LS), known as growth hormone (GH) receptor deficiency, is a rare form of inherited GH resistance. Sleep disorders were described as a common feature of adult LS patients, while no data are available in children. Bi-directional interactions between human sleep and the somatotropic system were previously described, mainly between slow wave sleep and the nocturnal GH surge.


OBJECTIVE
To analyze the sleep macro- and microstructure in LS and to evaluate the influence of substitutive insulin-like growth factor 1 (IGF-1) therapy on it.


METHODS
Two young LS females underwent polysomnography; the first study was performed during IGF-1 therapy, the second one after a 3-month wash-out period.


RESULTS
In both patients, the sleep macrostructure showed that time in bed, sleep period time, total sleep time, sleep efficiency and rapid eye movement (REM) percentage were all increased during wash-out. The sleep microstructure (cyclic alternating pattern: CAP) showed significantly higher EEG slow oscillations (A1%) in NREM sleep, both during IGF-1 therapy and wash-out.


CONCLUSIONS
Sleep macrostructure in LS children is slightly affected by substitutive IGF-1 therapy. Sleep microstructure shows an increase of A1%, probably related to abnormally high hypothalamic GHRH secretion, due to GH insensitivity.
Verrillo
Elisabetta
E
Respiratory Unit, Bambino Gesù Pediatric Hospital and Research Institute, Rome, Italy. elisabettaverrillo@hotmail.com
Bizzarri
Carla
C
Cappa
Marco
M
Bruni
Oliviero
O
Pavone
Martino
M
Cutrera
Renato
R
D000293:Adolescent; D002648:Child; D005260:Female; D019382:Human Growth Hormone / Q000378:metabolism; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000009:adverse effects / Q000627:therapeutic use*; D046150:Laron Syndrome / Q000188:drug therapy / Q000503:physiopathology*; D017286:Polysomnography; D012890:Sleep / Q000187:drug effects*; D012893:Sleep Wake Disorders / Q000209:etiology*
D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I