The Effect of Heparin Binding Epidermal Growth Factor on the Hypertrophy / Hyperplasia of Human Bladder Smooth Muscle

ABSTRACT

PUROPOSE The bladder outlet obstruction (BOO) causes a bladder hypertrophy and/or hyperplasia with time. Heparin binding epidermal growth factor like growth factor (HB-EGF) is a potent mitogen for bladder smooth muscle cell (BMSC), causing significant cellular hypertrophy. Few studies have evaluated the effect of HB-EGF on bladder hypertrophy or hyperplasia. We studied to evaluated the effect of HB-EGF on the hypertrophy or hyperplasia of human BSMC and fibroblast. MATERIAL AND METHODS: To evaluate the change of expression of HB-EGF mRNA of human BMSC under a constant stimuli of 40cm-H20 pressure during 0, 1, 3 and 5 hours, RT-PCR was perfromed. The human BMSC and bladder fibroblasts with the addition of the recombinant HB-EGF 25ng/ml were performed 3H-thymidine and 3H-leucine incorporation assay for DNA and protein production, respectively. RESULTS: The expression of HB-EGF mRNA in BMSC under a constant stimuli of 40cm-H20 pressure was up-regulated with time (p<0.05). The optimal concentration of HB-EGF was 25ng/ml. The 3H-Lecine and 3H-thymidine activity in both human BSMC and fibroblast were significantly increased in addition of 25ng/ml of HB-EGF (p<0.05 and p<0.05, respectively). CONCLUSIONS: Constant hydrostatic pressure induces the expression of HB-EGF in human BSMC. Subsequently HB-EGF induces hypertrophy and hyperplasia of human BSMC and fibroblast in vitro. Our data support that HB-EGF is one of relevant BOO-induced growth factors.