Chronic intermittent hypoxia/reoxygenation facilitate amyloid-β generation in mice.
Previous studies have shown a high prevalence of obstructive sleep apnea (OSA) among patients with Alzheimer's disease (AD). However, it is poorly assessed whether chronic intermittent hypoxia (CIH), which is a characteristic of OSA, affects the pathophysiology of AD. We aimed to investigate the direct effect of intermittent hypoxia (IH) in pathophysiology of AD in vivo and in vitro. In vivo, 15 male triple transgenic AD mice were exposed to either CIH or normoxia (5% O2 and 21% O2 every 10 min, 8 h/day for 4 weeks). Amyloid-β (Aβ) profile, cognitive brain function, and brain pathology were evaluated. In vitro, human neuroblastoma SH-SY5Y cells stably expressing wild-type amyloid-β protein precursor were exposed to either IH (8 cycles of 1% O2 for 10 min followed by 21% O2 for 20 min) or normoxia. The Aβ profile in the conditioned medium was analyzed. CIH significantly increased levels of Aβ42 but not Aβ40 in the brains of mice without the increase in hypoxia-inducible factor 1, alpha subunit (HIF-1α) expression. Furthermore, CIH significantly increased intracellular Aβ in the brain cortex. There were no significant changes in cognitive function. IH significantly increased levels of Aβ42 in the medium of SH-SY5Y cells without the increase in the HIF-1α expression. CIH directly and selectively increased levels of Aβ42 in the AD model. Our results suggest that OSA would aggravate AD. Early detection and intervention of OSA in AD may help to alleviate the progression of the disease.
Department of Respiratory Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan.
Satomi
S
Shiota
Hidenori
H
Takekawa
Shin-Ei
SE
Matsumoto
Kazuya
K
Takeda
Fariz
F
Nurwidya
Yasuko
Y
Yoshioka
Fumiyuki
F
Takahashi
Nobutaka
N
Hattori
Takeshi
T
Tabira
Hideki
H
Mochizuki
Kazuhisa
K
Takahashi
D000544:Alzheimer Disease / Q000150:complications / Q000235:genetics / Q000378:metabolism*; D053829:Amyloid Precursor Protein Secretases / Q000378:metabolism; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism; D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism; D045744:Cell Line, Tumor; D003072:Cognition Disorders / Q000209:etiology; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D006931:Hyperbaric Oxygenation; D000860:Hypoxia / Q000378:metabolism*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009447:Neuroblastoma / Q000473:pathology
D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D053829:Amyloid Precursor Protein Secretases; D016282:Aspartic Acid Endopeptidases; C509282:Bace1 protein, mouse