Am. J. Respir. Crit. Care Med., Vol 155, No. 4, 04 1997, 1316-1322.
Heat shock protein 72 level decreases during sleep in patients with obstructive sleep apnea syndrome
T Noguchi, K Chin, M Ohi, H Kita, N Otsuka, T Tsuboi, M Satoh, A Nakai, K Kuno and K Nagata
Department of Clinical Physiology, Chest Disease Research Institute, Kyoto University, Sakyo-ku, Japan.
Patients with obstructive sleep apnea syndrome (OSAS) suffer from stresses
related to repetitive apneas during sleep. To examine whether the level of
72 kDa heat shock protein (HSP72) increases during sleep, 11 OSAS patients
(apnea-hypopnea index: 63.5 +/- 36.1, mean +/- SD) underwent
polysomnography and their peripheral blood mononuclear cells (PBMC) were
isolated before, during, and after sleep. HSP72 level was determined by
Western blotting and hsp72 mRNA level was quantified by Northern blotting.
Nine normal subjects without OSAS were examined as normal controls. HSP72
level decreased progressively during sleep and its level at 8:00 A.M. was
78.0 +/- 17.5% of that at 8:00 P.M. (p < 0.01). No such decrease was
seen in normal subjects. When OSAS patients received nasal continuous
positive airway pressure (NCPAP) therapy, HSP72 level did not decrease
significantly. In untreated OSAS patients, hsp72 mRNA level decreased
during sleep (p < 0.01). When OSAS patients were treated with NCPAP
therapy, the decrease in hsp72 mRNA level was not observed. HSP72 level
before sleep in OSAS patients was higher than that in normal subjects (p
< 0.01). We concluded that repetitive apneas caused high HSP72 level
before sleep in OSAS patients and that NCPAP therapy had significant effect
on HSP72 levels during sleep.
