Stereological and biochemical analysis of the urethral edges in patients submitted to end-to-end anastomosis for bulbar urethral stricture

Abstract

ARTICLE INFO _________________________________________________________ ___________________Purpose: To study the morphologic alterations in the proximal and distal urethral edges from patients submitted to end-to-end bulbar urethroplasty. Materials and Methods:We analyzed 12 patients submitted to anastomotic urethroplasty to treat bulbar strictures less than 2.0 cm in length. After excision of the fibrotic segment to a 28Fr urethral caliber, we obtained biopsies from the spongious tissue of the free edges (proximal: PROX and distal: DIST). Controls included normal bulbar urethras obtained from autopsies of 10 age matched individuals. The samples were histologically processed for smooth muscle cells (SMC), elastic system fibers and collagen. Stereological analysis was performed to determine the volumetric density (Vv) of each element. Also, a biochemical analysis was performed to quantify the total collagen content. Results: Vv of SMC was reduced in PROX (31.48 ± 7.01 p < 0.05) and similar in DIST when compared to controls (55.65 ± 9.60%) with no statistical difference. Elastic fibers were increased in PROX (25.70 ± 3.21%; p < 0.05) and were similar to controls in DIST (15.87 ± 4.26%). Total collagen concentration in PROX (46.39 ± 8.20 µg/mg), and DIST (47.96 ± 9.42 µg/mg) did not differ from controls (48.85 ± 6.91 µg/mg). Type III collagen was similarly present in all samples. Conclusions: After excision of the stenotic segment to a caliber of 28Fr, the exposed and macroscopically normal urethral edges may present altered amounts of elastic fibers and SMC, but are free from fibrotic tissue. When excising the peri-stenotic tissue, the surgeon should be more careful in the proximal end, which is the most altered.

Extracellular matrix analysis of fibrosis: A step towards tissue engineering for urethral stricture disease

“…Elastin (ELN) was found in all samples and there was no difference in average expression. Previous reports on fibrotic tissue from urethral strictures showed more elastin fibres in the fibrotic lesion proximal to the urethral obstruction [ 8 ] compared to distal. We did not make this distinction between proximal and distal to the obstruction, but analysed the fibrotic lesion as a whole.…”

“…obstruction [8] compared to distal. We did not make this distinction between proximal and distal to the obstruction, but analysed the fibrotic lesion as a whole.…”

“…Previously, studies to the macro and micro architecture have shown that a large part of the structure of the CS consists of collagens, elastin and other ECM components [ 4 , 7 ]. It is known that USD affects the ECM of CS [ 8 , 9 ].…”