Tissue engineering of urethra: Systematic review of recent literature

AK, Pennisi CP. Quality of Reporting in Preclinical Urethral Tissue Engineering Studies: A Systematic Review to Assess Adherence to the ARRIVE Guidelines

Preclinical research within the area of urethral tissue engineering has not yet been successfully translated into an efficient therapeutic option for patients. This gap could be attributed, in part, to inadequate design and reporting of the studies employing laboratory animals. In this study, a systematic review was conducted to investigate the quality of reporting in preclinical studies utilizing tissue engineering approaches for urethral repair. The scope was on studies performed in rabbits, published between January 2014 and March 2020. Quality assessment of the data was conducted according to the Animal Research: Reporting of in Vivo Experiments (ARRIVE) guidelines by the scoring of a 38-item checklist in different categories. A total of 28 articles that fulfilled the eligibility criteria were included in the study. The range of ARRIVE score was from 0 to 100, taking into consideration having reported the item in question or not. The mean checklist score was 53%. The items that attained the highest scores included the number of animals utilized, the size of control and experimental groups, and the definition of experimental outcomes. The least frequently reported items included the data regarding the experimental procedure, housing and husbandry, determination and justification of the number of animals, and reporting of adverse events. Surprisingly, full disclosure about ethical guidelines and animal protocol approval was missing in 54% of the studies. No paper stated the sample size estimation. Overall, our study found that a large number of studies display inadequate reporting of fundamental information and that the quality of reporting improved marginally over the study period. We encourage a comprehensive implementation of the ARRIVE guidelines in animal studies exploring tissue engineering for urethral repair, not only to facilitate effective translation of preclinical research findings into clinical therapies, but also to ensure compliance with ethical principles and to minimize unnecessary animal studies.

Hyaluronic Acid Reduces Fibrosis in a Rabbit Model of Urethral Anastomosis

INTRODUCTION

Urethral stricture caused by fibrosis is a common medical condition, but top-line therapy for this pathology has a high recurrence rate. This study aimed to determine the efficacy of hyaluronic acid (HA) treatment in preventing the development of fibrosis in a rabbit model of urethral anastomosis.

MATERIALS AND METHODS

This experimental study involved 20 rabbits. HA (0.5 mL, 25 μg/mL) was applied in the experimental group (n = 10) during an experimental urethral anastomosis, and sterile saline (0.9%) solution was applied in the control group (n = 10). Animals underwent reoperation 12 weeks later for urethral resection. Fibrosis, inflammation, and urethral diameter were measured by two blinded pathologists at the site of the anastomosis.

RESULTS

The amount of inflammatory infiltrate was similar in both groups. The thicknesses of the collagen fiber band were 275.9 ± 62.3 and 373.4 ± 44.3 μm in the study and control groups (p = 0.001), respectively, and the urethral lumen diameters at the anastomosis site at follow-up were 2575 ± 167 and 2382 ± 214 μm, respectively (p = 0.04).

CONCLUSION

HA treatment reduced fibrosis at the anastomosis site during this experiment; we suggest further research to corroborate its efficacy in the treatment of urethral stricture.

Syringoceles of Cowper's ducts and glands in adult men

Cowper's syringoceles are uncommon, usually described in children and most commonly limited to the ducts. We describe more complex variants in an adult population affecting with varying degrees of severity, the glands themselves, and the complications they may lead to. One hundred consecutive urethrograms of patients with unreconstructed strictures were reviewed. Twenty-six patients (mean age: 41.1 years) with Cowper's syringoceles who were managed between 2009 and 2016 were subsequently evaluated. Presentation, radiological appearance, treatment (when indicated), and outcomes were assessed. Of 100 urethrograms in patients with strictures, 33.0% demonstrated filling of Cowper's ducts or glands, occurring predominantly in patients with bulbar strictures. Only 1 of 26 patients with non-bulbar strictures had a visible duct/gland. Of 26 symptomatic patients, 15 presented with poor flow. In four patients, a grossly dilated Cowper's duct obstructed the urethra. In the remaining 11 patients, a bulbar stricture caused the symptoms and the syringocele was identified incidentally. Eight patients presented with perineal pain. In six of them, fluoroscopy and magnetic resonance imaging (MRI) revealed complex multicystic lesions within the bulbourethral glands. Four patients developed perineoscrotal abscesses. In the 11 patients with strictures, the syringocele was no longer visible after urethroplasty. In three of four patients with urethral obstruction secondary to a dilated Cowper's duct, this resolved after transperineal excision (n = 2) and endoscopic deroofing (n = 1). Five of six patients with complex syringoceles involving Cowper's glands were excised surgically with symptomatic relief in all. In conclusion, Cowper's syringocele in adults is more common than previously thought and may cause lower urinary tract symptoms or be associated with serious complications which usually require surgical treatment.

Urine as a Main Effector in Urological Tissue Engineering-A Double-Edged Sword

In order to reconstruct injured urinary tract tissues, biodegradable scaffolds with autologous seeded cells are explored in this work. However, when cells are obtained via biopsy from individuals who have damaged organs due to infection, congenital disorders, or cancer, this can result in unhealthy engineered cells and donor site morbidity. Thus, neo-organ construction through an alternative cell source might be useful. Significant advancements in the isolation and utilization of urine-derived stem cells have provided opportunities for this less invasive, limitless, and versatile source of cells to be employed in urologic tissue-engineered replacement. These cells have a high potential to differentiate into urothelial and smooth muscle cells. However, urinary tract reconstruction via tissue engineering is peculiar as it takes place in a milieu of urine that imposes certain risks on the implanted cells and scaffolds as a result of the highly cytotoxic nature of urine and its detrimental effect on both growth and differentiation of these cells. Both of these projections should be tackled thoughtfully when designing a suitable approach for repairing urinary tract defects and applying the needful precautions is vital.

Cells Involved in Urethral Tissue Engineering: Systematic Review

The urethra is part of the lower urinary tract and its main role is urine voiding. Its complex histological structure makes urethral tissue prone to various injuries with complicated healing processes that often lead to scar formation. Urethral stricture disease can affect both men and women. The occurrence of this pathology is more common in men and thus are previous research has been mainly oriented on male urethra reconstruction. However, commonly used surgical techniques show unsatisfactory results because of complications. The new and progressively developing field of tissue engineering offers promising solutions, which could be applied in the urethral regeneration of both men´s and women´s urethras. The presented systematic review article offers an overview of the cells that have been used in urethral tissue engineering so far. Urine-derived stem cells show a great perspective in respect to urethral tissue engineering. They can be easily harvested and are a promising autologous cell source for the needs of tissue engineering techniques. The presented review also shows the importance of mechanical stimuli application on maturating tissue. Sufficient vascularization and elimination of stricture formation present the biggest challenges not only in customary surgical management but also in tissue-engineering approaches.