Two cases of female urethral reconstruction with acellular porcine urinary bladder matrix

Preparation and Use of Decellularized Extracellular Matrix for Tissue Engineering

The multidisciplinary fields of tissue engineering and regenerative medicine have the potential to revolutionize the practise of medicine through the abilities to repair, regenerate, or replace tissues and organs with functional engineered constructs. To this end, tissue engineering combines scaffolding materials with cells and biologically active molecules into constructs with the appropriate structures and properties for tissue/organ regeneration, where scaffolding materials and biomolecules are the keys to mimic the native extracellular matrix (ECM). For this, one emerging way is to decellularize the native ECM into the materials suitable for, directly or in combination with other materials, creating functional constructs. Over the past decade, decellularized ECM (or dECM) has greatly facilitated the advance of tissue engineering and regenerative medicine, while being challenged in many ways. This article reviews the recent development of dECM for tissue engineering and regenerative medicine, with a focus on the preparation of dECM along with its influence on cell culture, the modification of dECM for use as a scaffolding material, and the novel techniques and emerging trends in processing dECM into functional constructs. We highlight the success of dECM and constructs in the in vitro, in vivo, and clinical applications and further identify the key issues and challenges involved, along with a discussion of future research directions.

Single-layer acellular porcine bladder matrix as graft in corporoplasty for ventral curvature in pediatric proximal hypospadias repair: an initial experience

BACKGROUND

Single-layer ACellࣨ Cytalࣨ matrix (ACell Inc, Columbia, MD) is a commercially available, acellular scaffold derived from porcine bladder epithelial basement membrane and tunica propria. We describe our initial experience using Cytalࣨ as corporal graft in pediatric patients who underwent correction of ventral curvature in proximal hypospadias repair.

METHODS

A retrospective review of a single-institution, four surgeon hypospadias database was performed between January 2020 and December 2021. Outcomes assessed were postoperative recurrent ventral curvature, corporal diverticulum, scarring on corporoplasty site on physical exam, and parental reports of atypical adverse effects.

RESULTS

Ten males underwent correction of ventral curvature with Cytalࣨ as corporal graft for correction of ventral curvature were identified. All completed planned operations. Median age was 18.6 months (IQR 14.6-27.0). Median follow up was 14.1 months (IQR 8.9-16.5). Mean ventral curvature after degloving was 80 ± 50 degrees. All patients had straight erections. Nine of the 10 patients had straight erections verified at a subsequent artificial erection test at least 6 months from the corporoplasty (90%). The remaining patient underwent a double face onlay-tube-onlay transverse island preputial flap as a single-stage hypospadias repair and did not require any additional procedures. He had straight erections per parental history. None developed corporal diverticulum or demonstrated induration at site of corporoplasty on physical exam. There were no parental reports of atypical adverse systemic effects.

CONCLUSIONS

In the short term, single-layer Cytalࣨ is effective as corporal graft for correction of ventral curvature in proximal hypospadias repairs without incurring additional donor site morbidity.

Outcome of urethral reconstruction among vesico-vaginal fistula patients: a cross-sectional study

Background

Obstetric fistula (OF) complicated by urethral loss (UL) poses a challenge to both the fistula surgeon and obstetric fistula patient. The involvement of the urethra and urethral closure mechanism in OF is an important determinant of successful closure of fistula and restoration of urinary continence. OF with UL is often associated with unsuccessful repair outcome. We describe urethral reconstruction in genital tract fistula patients with UL and the outcomes of the repair.

Methods

Aim To review the clinical characteristics and outcome of vesico-vaginal fistula associated urethral loss following urethral reconstruction.

This was a descriptive cross-sectional study conducted at the University College Hospital, Ibadan, Nigeria. A 5-year prospective data of all vesico-vaginal fistula patients with urethral loss (2011–2016) were reviewed and analysed. Data collected include socio-demographic and obstetric characteristics; cause of the fistula; and fistula characteristics—type of fistula, number of previous repairs, urethral loss, outcome of repair and follow-up. Data were entered and analysed using IBM SPSS version 20.

Results

Urethral loss occurred in 23 (15.3%) out of 150 women with OF; these women had urethral reconstruction surgery. The commonest type of urethral loss encountered in this cohort was proximal urethral loss which was seen in 12 (52.2%) patients. The most common types of fistula seen with urethral loss were large vesico-vaginal fistula (34.8%) and mid-vaginal fistula (26.1%). More than half of the women (56.6%) had previous unsuccessful repair at other facilities before presentation. The fistula closure rate was high (82.6%) regardless of type of urethral loss. Among the women with successful closure of OF with UL, about 36.8% had urinary stress incontinence post-fistula repair.

Conclusion

Urethral loss appears to be a rare complication of obstetric fistula. Successful closure with stress incontinence was seen in a sizeable number of women with OF with UL. Preoperative assessment for determinant of post-repair incontinence and surgical repair by experienced surgeons will improve successful outcome of repair in women with obstetric fistula with UL.

Treatment of Urethral Stricture Disease in Women: Nonsystematic Review of Surgical Techniques and Intraoperative Considerations

Female urethral strictures are rare, but underdiagnosed pathologies that can cause voiding dysfunction. These strictures are best managed with open reconstruction, as endoscopic treatments have high rates of failure. A flap urethroplasty can be performed with vaginal, labial or bladder tissue. Meanwhile, graft urethroplasties can utilize vaginal, labial, buccal or lingual tissue. It is important to consider the etiology and type of stricture, local vascularity, and prior attempts at repair when selecting the type of repair. Multiple different techniques have been described with theoretical advantages to each one. While some studies have reviewed a few of the reconstructive techniques to treat female urethral strictures, no single study has accounted for each individual technique. In this review, we discuss techniques captured by a number of systematic reviews and other articles. We will herein focus on reviewing and describing each unique technique of reconstruction in the setting of female urethral stricture.

Urinary Bladder Matrix Does Not Improve Tenogenesis in an In Vitro Equine Model

Extracellular matrix (ECM) is responsible for tendon strength and elasticity. Healed tendon ECM lacks structural integrity, leading to reinjury. Porcine urinary bladder matrix (UBM) provides a scaffold and source of bioactive proteins to improve tissue healing, but has received limited attention for treating tendon injuries. The objective of this study was to evaluate the ability of UBM to induce matrix organization and tenogenesis using a novel in vitro model. We hypothesized that addition of UBM to tendon ECM hydrogels would improve matrix organization and cell differentiation. Hydrogels seeded with bone marrow cells (n = 6 adult horses) were cast using rat tail tendon ECM ± UBM, fixed under static tension and harvested at 7 and 21 days for construct contraction, cell viability, histology, biochemistry, and gene expression. By day 7, UBM constructs contracted significantly from baseline, whereas control constructs did not. Both control and UBM constructs contracted significantly by day 21. In both groups, cells remained viable over time and changed from round and randomly oriented to elongated along lines of tension with visible compaction of the ECM. There were no differences over time or between treatments for nuclear aspect ratio, DNA, or glycosaminoglycan content. Decorin, matrix metalloproteinase 13, and scleraxis expression increased significantly over time, but not in response to UBM treatment. Mohawk expression was constant over time. Cartilage oligomeric matrix protein expression decreased over time in both groups. Using a novel ECM hydrogel model, substantial matrix organization and cell differentiation occurred; however, the addition of UBM failed to induce greater matrix organization than tendon ECM alone. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1848-1859, 2019.