Heat shock protein 70 as a biomarker of heat stress in a simulated hot cockpit.
BACKGROUND
Fighter pilots are frequently exposed to high temperatures during high-speed low-level flight. Heat strain can result in temporary impairment of cognitive functions and when severe, loss of consciousness and consequent loss of life and equipment. Induction of stress proteins is a highly conserved stress response mechanism from bacteria to humans. Induced stress protein levels are known to be cytoprotective and have been correlated with stress tolerance. Although many studies on the heat shock response mechanisms have been performed in cell culture and animal model systems, there is very limited information on stress protein induction in human subjects.


OBJECTIVE
Heat shock proteins (Hsp), especially Hsp70, may be induced in human subjects exposed to high temperatures in a hot cockpit designed to simulate heat stress experienced in low flying sorties.


METHODS
Six healthy volunteers were subjected to heat stress at 55 degrees C in a high temperature cockpit simulator for a period of 1 h at 30% humidity. Physiological parameters such as oral and skin temperatures, heart rate, and sweat rate were monitored regularly during this time. The level of Hsp70 in leukocytes was examined before and after the heat exposure in each subject.


CONCLUSIONS
Hsp70 was found to be significantly induced in all the six subjects exposed to heat stress. The level of induced Hsp70 appears to correlate with other strain indicators such as accumulative circulatory strain and Craig's modified index. The usefulness of Hsp70 as a molecular marker of heat stress in humans is discussed.
Kumar
Yadunanda
Y
Department of Biochemistry, Indian Institute of Science, Bangalore, India.
Chawla
Anuj
A
Tatu
Utpal
U
D000328:Adult; D000401:Aircraft; D015415:Biomarkers / Q000097:blood; D001831:Body Temperature; D001833:Body Temperature Regulation / Q000502:physiology; D001835:Body Weight; D018840:HSP70 Heat-Shock Proteins / Q000097:blood*; D006339:Heart Rate / Q000502:physiology; D018882:Heat Stress Disorders / Q000097:blood* / Q000209:etiology; D006801:Humans; D009784:Occupational Diseases / Q000097:blood*; D016273:Occupational Exposure / Q000009:adverse effects
D015415:Biomarkers; D018840:HSP70 Heat-Shock Proteins