The structure and autonomic innervation of the vesico‐ureteric junction in cases of primary ureteric reflux

Abstract

Objective To determine the histological structure and autonomic innervation of the vesico‐ureteric junction (VUJ) in cases of primary ureteric reflux, to compare the results with those reported previously for non‐refluxing VUJs and thus determine possible structural anomalies which could be responsible for vesico‐ureteric reflux (VUR). Materials and methods Nineteen specimens of VUJs with reflux were obtained from four males and 10 females undergoing ureteric reimplantation. Serial frozen sections were cut and stained either with Masson’s trichrome or immunostained for protein gene product (PGP 9.5), a general nerve marker, dopamine beta hydroxylase (DβH), a marker for noradrenergic nerves, or neuropeptide Y (NPY). Results Longitudinally orientated muscle bundles of narrow diameter accompanied the ureter to its termination at the ureteric orifice, where they merged with those of the superficial trigone. In some specimens, an additional muscle component was identified, situated on the outer aspect of the ureteric muscle coat, consisting of an incomplete layer of distinctive muscle whose constituent cells formed an interlacing meshwork. Occasionally, specimens included detrusor muscle which consisted of relatively large diameter compact bundles separated from the ureter by a connective tissue sheath. DβH‐ and NPY‐immunoreactive (‐IR) nerves were numerous among the ureteric muscle bundles. Many NPY‐IR nerves occurred within the detrusor muscle while DβH‐IR nerves were mainly perivascular. When present, the outer muscle component was richly innervated by both DβH‐ and NPY‐IR nerves. PGP immunoreactivity varied among regions in the same section, PGP‐IR nerves frequently being less numerous than those containing DβH or NPY. Conclusion These results indicate that the morphology of the VUJ in cases of VUR is indistinguishable from the normal VUJ described previously. Furthermore, the density and distribution of DβH‐ and NPY‐IR nerves is identical to that in controls. However, the antigenicity of PGP in the reflux specimens appears to be masked in some regions by an unknown factor.

The utilization of stents in the management of primary obstructive megaureters requiring intervention before 1 year of age

“…This observation may also explain the frequent spontaneous resolution of primary megaureters within the first 2 years of postnatal life, when the circular muscle pattern, which is typical of the fetal ureter, changes progressively into the double muscle layers of the full-term infant [9]. Other studies have implicated a thick sleeve of muscle around the distal portion of the ureter [10], increased deposition of collagen fibres [11] and dysregulated neuromodulation in the juxtavesical segment of obstructed megaureters [12]. Payabvash et al [13] studied a series of obstructed ureters from patients between 6 months and 2 years of age, and showed the presence of increased myocyte apoptosis, and reduced vascular and neural elements, associated with increased collagen fibres.…”

Endoscopic placement of double-J ureteric stents in children as a treatment for primary obstructive megaureter

“…described a thick sleeve of muscle around the distal ureter. [6] Lee et al . described abnormal collagen deposition[7] and Hertle and Nawrath described abnormal neuromodulation in obstructed megaureters.…”

The Distribution of Noradrenergic Nerves in the Human Lower Urinary Tract

“…The late development of noradrenergic nerves at the UVJs has also been reported in dogs where it was suggested that a further delay in development of the noradrenergic control of the intramural ureters might be a cause of postnatal ureteric reflux [33]. However a recent study of the UVJs removed from children (1–10 years of age) undergoing ureteric reimplantation for primary ureteric reflux failed to demonstrate any difference in the structure or innervation when compared with controls [34]. …”