Imbalance in extracellular matrix degradation in urethral stricture

Rectifying disorder of extracellular matrix to suppress urethral stricture by protein nanofilm-controlled drug delivery from urinary catheter

Urethral stricture secondary to urethral injury, afflicting both patients and urologists, is initiated by excessive deposition of extracellular matrix in the submucosal and periurethral tissues. Although various anti-fibrotic drugs have been applied to urethral stricture by irrigation or submucosal injection, their clinical feasibility and effectiveness are limited. Here, to target the pathological state of the extracellular matrix, we design a protein-based nanofilm-controlled drug delivery system and assemble it on the catheter. This approach, which integrates excellent anti-biofilm properties with stable and controlled drug delivery for tens of days in one step, ensures optimal efficacy and negligible side effects while preventing biofilm-related infections. In a rabbit model of urethral injury, the anti-fibrotic catheter maintains extracellular matrix homeostasis by reducing fibroblast-derived collagen production and enhancing metalloproteinase 1-induced collagen degradation, resulting in a greater improvement in lumen stenosis than other topical therapies for urethral stricture prevention. Such facilely fabricated biocompatible coating with antibacterial contamination and sustained-drug-release functionality could not only benefit populations at high risk of urethral stricture but also serve as an advanced paradigm for a range of biomedical applications.

Deciphering the Role of TGF-β1 in Altering Collagen I and Collagen III in the New Zealand Rabbit's (Oryctolagus cuniculus) Urethral Wall in Urethral Stricture Development

Background

Presently, there's a lack of standardization in animal models used for studying urethral stricture. Transforming Growth Factor Beta 1 (TGF-β1) is known to regulate the deposition of extracellular matrix in both normal and pathological conditions. This factor holds promise as a potential model for simulating urethral stricture.

Objective

This study aims to investigate the impact of Transforming Growth Factor Beta 1 (TGF-β1) on Collagen I and Collagen III within the urethral wall of New Zealand Rabbits (Oryctolagus cuniculus) in the context of developing urethral stricture in animal models.

Methods

We conducted genuine laboratory experiments using Male New Zealand rabbits (Oryctolagus cuniculus), which were categorized into five groups: control, placebo, and three treatment groups (TGF-β1 injections of 1 µg, 2 µg, 4 µg). After a duration of 6 weeks, we conducted urethrography, histopathological analysis, and assessed the formation of collagen I and collagen III within the urethral wall.

Results

Elevating the dosage of TGF-β1 led to a reduction in the average urethral lumen diameter of rabbits (29.3% in the 2µg group and 34% in the 4µg group) compared to the control group. In fact, three rabbits experienced a decrease of ≤ 50% in their urethral lumen diameter. As the doses of TGF-β1 increased, we observed significant increases in the density of collagen I, and collagen III in both the periluminal and peripheral regions of the urethral spongiosum. Additionally, there was a tendency for the collagen I/collagen III ratio to decrease in the periluminal region, with collagen III density surpassing that of collagen I. In the peripheral spongiosa area, notable mean differences were observed between the control group, 1T, and 2T groups, with collagen I density tending to be higher than that of collagen III. Furthermore, the percentage of urethral lumen diameter exhibited a robust negative correlation with periluminal collagen I density (r = -0.672, p = 0.001), peripheral spongiosa collagen I density (r = -0.603, p = 0.005), periluminal collagen III density (r = -0.717, p = 0.001), and an exceptionally strong negative correlation with collagen III density of peripheral spongiosa (r = -0.804, p = 0.000).

Conclusion

TGF-β1 exerts an influence on altering the composition of collagen I and collagen III within the urethral wall of rabbits, leading to a reduction in the diameter of the urethral lumen. Further research is warranted to determine the optimal dose of TGF-β1 required to induce urethral stricture effectively.

TGF-β1 Effects on Total Collagen of the New Zealand Rabbit's Urethral Wall (Oryctolagus cuniculus) in Animal Models of Urethral Stricture

Background

Currently, animal models of urethral stricture are not standardized. Transforming Growth Factor Beta 1 (TGF-β1) regulates extracellular matrix deposition in homeostatic and pathological responses.

Objective

The aim of this study was to present the potential model to be developed as a urethral stricture.

Methods

True experimental laboratory research was conducted by using Male New Zealand rabbits (Oryctolagus cuniculus), which were divided into 5 groups; control, placebo, and 3 treatment groups (TGF-β1 injection of 1 µg, 2 µg, 4 µg). Urethrography, histopathological analysis, and evaluation of total collagen formation of the urethral wall were performed after 6 weeks.

Results

An increase in the dose of TGF-β1 decreased the mean rabbit's urethral lumen diameter (29.3% in the 2µg group and 34% in the 4µg group) compared to controls. Three rabbits decreased as much as ≤ 50% in urethral lumen diameter. Significant increases in total collagen density in the periluminal and peripheral urethral spongiosum were noted by increasing doses of TGF-β1. The percentage of urethral lumen diameter has a strong negative correlation with periluminal total collagen density (r = -0,798; p = 0,000) and very strong negative correlation with peripheral spongiosa total collagen density (r = -0,748, p = 0,000).

Conclusion

TGF-β1 plays a role in changing total collagen compositions of the rabbit's urethral wall, decreasing the urethral lumen diameter. Further research with increasing doses of TGF-β1 is needed to determine the effective dose of TGF-β1 in inducing urethral stricture.

Molecular Mechanisms and Current Pharmacotherapy of Peyronie's Disease: A Review

Peyronie’s disease (PD) is a localized fibrotic lesion of the penis that has adverse effects on men’s health. In this review, we summarized the molecular mechanisms and pharmacotherapies of PD. A literature search was conducted using PubMed and Cochrane Library during 2001–2020. Although no oral or topical medication demonstrated efficacy in monotherapy of PD, several intralesional medications have yielded promising results. Currently, the effective strategy in management of PD should be combined modality therapy, including but not limited to pharmacotherapy, mechanical therapy, and psychotherapy. Meanwhile, basic research is still necessary to facilitate the development of novel and more reliable treatments. In future, more attention should be given simultaneously to epigenetic changes, inflammatory cytokines, the abnormal wound-healing process, and profibrotic and anti-fibrotic factors to provide more options for this refractory disease.