Cardio-protective role of heat shock protein 70 (HSP 70) among heat-exposed workers

SA, F., S. AM, S. DA, and R. LA, "Cardio-protective role of heat shock protein 70 (HSP 70) among heat-exposed workers ", Egyptian journal of Industrial Medicine, vol. 34, issue 1, pp. 29-42, 2010.



Aim: This work aimed at studying the prevalence of ischemic heart diseases (IHD) among heat-exposed workers and the extent of having the high risk factors particularly dyslipidemia and hypertension among this group of workers. Besides, the cardio-protective role of heat shock protein 70 (HSP 70), as a molecular heat exposure biomarker, was clarified. Subjects: The study subjects consisted of a heat-exposed 29 bakers group employed in 10 manual bakeries and a matched heat unexposed group (n= 29). Methods: Every individual underwent occupational and clinical history taking, resting electrocardiogram (ECG), estimation of serum lipid profile parameters,{ total cholesterol (TC), high density lipoprotein (HDL-C), TC/HDL-C ratio, low density lipoprotein (LDL-C), triglycerides (TG)} and heat shock protein 70 (HSP70). Results: Analysis of history showed significantly higher prevalence of heat cramps ( 27.5%) and heat rash ( 34.5%) among the heat-exposed group. Resting ECG revealed ischemic manifestations in 20.6% of the heat-exposed workers versus 13.7% of their controls (P<0.05). Marked significant increase in all lipid profile parameters was detected in the heat-exposed individuals with positive correlation with duration of work. The HSP 70 level was 2 times higher among the heat-exposed group. The individuals having ischemic manifestations had lower HSP70 level. Conclusion: Working in hot environments can induce unfavorable increase in blood lipids which predisposes workers to IHD. As HSP 70 which is known to have a cardio-protective role declines with age with consequent diminishing of its cardio-protective role, elderly workers exposed to heat would have higher incidence of IHD which necessitates avoidance of working under hot conditions.

Key Words:
Heat , Heat illness, Heat shock protein 70, Ischemic heart diseases, , Dyslipidemia, ECG.