Age-related structural changes of the urethral plate in hypospadias.

PURPOSE: To describe age-related changes in the extracellular matrix (ECM) of the human urethral plate in patients operated on for hypospadias, specifically describing histological features and determining the differences in the major components of the ECM, and thus providing an evaluation of the quality and wound healing potential of the urethral tissue.

PATIENTS AND

METHODS

Urethral plate samples were obtained from 16 patients who underwent hypospadias repair (6 months-53 years of age), not previously submitted to any surgery. As a control group, male urethras were obtained from five fetuses. ECM structural characterization was performed by Hematoxylin and Eosin, Masson's trichrome, Weigert's resorcin-fuchsin, and Sirius red. The concentration of total collagen was determined by a hydroxyproline assay.

RESULTS

Urethral plates were lined with squamous epithelium. Most urethral plate samples showed well-vascularized connective tissue and typical vascular sinusoids surrounded by an ECM with smooth muscle cells, collagen, elastic fibers and fibroblasts. ECM of the older urethral plates was characterized by abundant collagen content (types I and III), scarce elastic fibers, low cellular density, and no vascular sinusoids. Total collagen concentration increased significantly with aging (r = 0.798; p = 0.006).

CONCLUSIONS

Urethral plates of hypospadias present important age-related structural changes. These changes may play a role in urethral healing following hypospadias repair, although this subject deserves more investigation.