Activation of the TGF-beta 1/Smads/alpha-SMA pathway is related to histological and functional changes in children with neurogenic bladder

This research is to investigate the expression of the TGF-beta 1/Smads/alpha-SMA pathway and its effect on bladder histology and function in children with neurogenic bladder (NB). The bladder specimens from 10 children with NB and 8 children with vesicoureteral junction obstruction were collected into the NB and control groups. The expression of TGF-beta 1, Smad2, Smad3, Smad4, Smad6, alpha-SMA, fibronectin, collagen I and collagen III in bladder tissues was detected. In addition, the histological characteristics of the bladder were evaluated. A preoperative urodynamic study was performed on all children with NB. We analysed the correlations among the expression of the marker protein a-SMA in myofibroblasts, effector cells of the pathway, and bladder function parameters. Compared with those in the control group, the expression of TGF-beta 1, Smad2, Smad3, Smad4, alpha-SMA, fibronectin, collagen I and collagen III was significantly increased in the NB group, while the expression of Smad6 was decreased (p < 0.01). HE and Masson staining in the NB group showed increased collagen levels and hypertrophy of smooth muscle cells. Children with NB had a low bladder volume ratio (BVR), low compliance (oC) and high maximum bladder pressure, low maximum flow rate, large postvoid residual volume, low bladder contraction index and low bladder voiding efficiency. The expression of alpha-SMA was negatively correlated with the BVR (r = - 0.7066, P = 0.0223) and oC (r = - 0.6516, P = 0.0412). We conclude that the TGF-beta 1/Smads/alpha-SMA pathway is activated in the bladder tissue of children with NB and may be involved in the processes causing histological and functional changes.