Heat shock proteins HSP27 and HSP70 in unilateral obstructed kidneys

Unilateral ureteropelvic junction obstruction (UPJO), a condition involving injury to the kidney, leads to vasoconstriction, macrophage infiltration, oxidative stress, and tubulointerstitial fibrosis. In the present study we analyzed in 22 children, the impact of UPJO on expression of HSP27 and HSP70 and related the changes to renal function and duration of obstruction. Kidney function was evaluated, and renal biopsies were obtained for immunohistochemical and western blot analyses at the time of surgery. Kidney tissue from 5 children of similar age, removed because of various malignancies, was used as control. Increased HSP27, with an expression pattern related to the duration of the obstruction, was noted in proximal tubules (PTs), cortical collecting ducts (CCDs), and medullary collecting ducts. Strong HSP27 staining in cytoplasm and nuclei of these segments appeared in children with kidney obstruction for 2.1+/-0.41 years. HSP70 showed a close spatial expression pattern with that of HSP27. The increased staining of HSP70 in PTs and CCDs was related to the decreased glomerular filtration rate. The constitutive/cognate form of HSP70 (HSC72) was absent. These results support the concept that HSP27 and HSP70 are involved in the adaptive response of the human kidney to congenital UPJO.