Changed expression of heat shock proteins in various pathological findings in placentas with intrauterine fetal growth restriction.

Heat shock proteins (HSPs) are activated in the cells of most organisms in response to sublethal heat shock and other stressors. It has been reported that HSP27, HSP60, HSP70, and HSP90 are expressed in normal human placenta, and it was thought that these HSPs play a role in the demonstration of cell viability and function. In this study, we performed an immunohistochemical (IHC) study of these HSPs for 27 placentas that had complicated intrauterine fetal growth restriction (IUGR) and compared the IHC findings with the pathological findings. To quantify HSP27, HSP60, HSP70, and HSP90, immunoreacted cells in the chorionic villi, syncytiotrophoblasts (ST), and cytotrophoblasts (CT) were counted. In thrombus, excessive syncytial knots, and avascular villi, the expression of HSPs was higher in the pathological sections compared to control in both ST and CT. In contrast, all HSPs decreased in both ST and CT around the infarction region. The data suggested that chorionic villi cells locally responded to some stresses, e.g., hypoxia and increase or decrease in the expression of HSPs. Although the villous cells around the infarction histologically appear viable, they may have received lethal damage, and as a result the expression of HSPs was decreased. These results are expected to improve our understanding of the pathological findings of IUGR in placentas, including the quality, damage, and function of the chorionic villi.