Cardio-Protective Role of Heat Shock Protein 70 (Hsp 70) Among Heat-Exposed Workers

Abstract

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 cardioprotective 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.