Precise Characterization and 3-Dimensional Reconstruction of the Autonomic Nerve Distribution of the Human Ureter

Abstract

Purpose: We sought to characterize and 3-dimensionally reconstruct the distribution of the autonomic innervation of the human ureter.

Materials and methods: Three male and 3 female pairs of ureters were evaluated at 2 mm serial transverse sections along the entire length of the ureter. The location of nerve tissue was immunohistochemically identified using the neuronal marker, S100 protein. ImageJ software was used to calculate nerve count and density in the adventitia and smooth muscle. Blender® graphics software was used to create a 3-dimensional reconstruction of autonomic nerve distribution.

Results: Within the adventitia nerve density was highest in the mid and distal ureter (females 2.87 and 2.71 nerves per mm², and males 1.68 and 1.69 nerves per mm²) relative to the proximal ureter (females and males 1.94 and 1.22 nerves per mm², respectively, p >0.0005). Females had significantly higher nerve density throughout the adventitia, especially in the distal ureter (2.87 vs 1.68 nerves per mm², p <0.0005). In smooth muscle the nerve density progressively increased from the proximal to the distal ureter (p >0.0005). Smooth muscle nerve density was similar in the 2 genders (p = 0.928). However, in females nerve density was significantly higher in the first 2 cm of the distal ureter relative to the second 2 cm (3.6 vs 1.5 nerves per mm², p <0.001) but not in males (3.0 vs 2.1 nerves per mm², p = 0.126).

Conclusions: Nerve density was highly concentrated at the distal ureter in the adventitia and smooth muscle of the male and female human ureters. The female ureter had greater nerve density in the adventitia, and in smooth muscle nerves were significantly concentrated at the ureteral orifice and the ureteral tunnel.

Keywords: adventitia; autonomic pathways; imaging; muscle; smooth; three-dimensional; ureter.