Peptide growth factors in normal and hypertrophied bladder

The bladder is a dynamic organ that responds to the stress of outlet obstruction by rapidly increasing in mass and cellular content to compensate for increased urethral resistance. If the outlet obstruction is released prior to decompensation, the hypertrophied bladder will shrink, returning to normal size and cellularity. However, with chronic obstruction the bladder will continue to increase in mass, developing drastic alterations in the amount and composition of the extracellular matrix and, ultimately, losing the ability to function. The extensive tissue remodeling associated with each of these changes requires different bladder components to undergo cellular proliferation, cellular hypertrophy, and even programmed cell death (apoptosis). Each of these cellular processes is known to be regulated by various peptides that are referred to as growth factors. Herein we provide an overview of the growth factors that are known to influence the bladder in addition to a variety of experimental animal studies that putatively identify a role of four particular growth factors [basic fibroblast growth factor (bFGF), transforming growth factor-beta (TGF-beta), nerve growth factor (NGF), and epidermal growth factor (EGF)] in the obstructive bladder response.