Using porcine acellular collagen matrix (Pelvicol®) in bladder augmentation: experimental study

Bladder Augmentation Using Lyoplant®: First Experimental Results in Rats

Background

Congenital defects of the urinary bladder (micro- or contracted bladder, bladder exstrophy) remain a challenging problem for pediatric surgeons. Even when conservative treatment options are fully exhausted, irreversible renal dysfunction can be observed in a large number of cases that can even lead to chronic renal failure and the need for kidney transplantation. To protect kidney function bladder augmentation using intestinal tissue is commonly applied as the standard treatment method. However due to the unphysiological nature of intestinal tissue a number of problems and complications such as urinary tract infections or bladder stone formation limit the clinical success of this approach. Moreover a number of substitutes for the implementation of a bladder augmentation have been tested without success to date. Here we used an experimental model to test wether the biocompatible collagen mesh Lyoplant may be a suitable candidate for bladder augmentation.

Methods

We implanted a biocompatible collagen mesh (Lyoplant^®) in a bladder defect rat model for bladder augmentation (Lyoplant^®-group: n = 12; sham group n = 4). After 6 weeks the abdomen was reopened and the initial implant as well as the bladder were resected for histological and immunohistochemical examination.

Results

All but one rat exhibited physiological growth and behaviour after the operation without differences between the Lyoplant^®-group (n = 12) and the sham group (n = 3). One rat from the sham group had to be excluded because of a suture leakage. No wound healing complications, wound infections and no herniation were observed. After 5 weeks the implants showed an adequate incorporation in all cases. This was confirmed by immunohistological analyses where a significant cell infiltration and neovascularization was observed.

Conclusion

In summary, Lyoplant^® appears to be a promising tool in experimental bladder augmentation/regeneration in rats.

Augmentation cystoplasty and extracellular matrix scaffolds: an ex vivo comparative study with autogenous detubularised ileum

Background

Augmentation cystoplasty (AC) with autogenous ileum remains the current gold standard surgical treatment for many patients with end-stage bladder disease. However, the presence of mucus-secreting epithelium within the bladder is associated with debilitating long-term complications. Currently, decellularised biological materials derived from porcine extracellular matrix (ECM) are under investigation as potential augmentation scaffolds. Important biomechanical limitations of ECMs are decreased bladder capacity and poor compliance after implantation.

Methodology/Principal Findings

In the present ex vivo study a novel concept was investigated where a two-fold increase in ECM scaffold surface-area relative to the resected ileal segment was compared in ovine bladder models after AC. Results showed that bladder capacity increased by 40±4% and 37±11% at 10 mmHg and compliance by 40.4±4% and 39.7±6% (ΔP = 0–10 mmHg) after AC with ileum and porcine urinary bladder matrix (UBM) respectively (p<0.05). Comparative assessment between ileum and UBM demonstrated no significant differences in bladder capacity or compliance increases after AC (p>0.05).

Conclusions

These findings may have important clinical implications as metabolic, infective and malignant complications precipitated by mucus-secreting epithelium are potentially avoided after augmentation with ECM scaffolds.

Histerocystoplasty: a novel surgical procedure in the rat

BACKGROUND

Enterocystoplasties are associated to complications. To avoid them, different types of tissue templates have been used to augment the bladder and induce native bladder regeneration.

MATERIALS AND METHODS

A novel surgical technique for bladder reconstruction using autologous uterine tissue was evaluated in a rat model. Forty-two female Wistar rats were randomly allocated into three groups: sham-operation hysterocystorrhaphy (n = 12), hysterocystoplasty (n = 18), and control (n = 12). Two weeks after surgery, ultrasound examination of the bladder was performed. At 2, 4, or 6 mo after surgery, the rats were anesthetized and blood and urine samples were taken. They were then euthanized and post-mortem and histologic examination were performed. Ultrasound examination, analytical parameters and weight control, as well as gross and histologic examination were performed in all the operated animals. The statistical analysis was performed using Kruskal-Wallis and the extension of Fisher's exact tests. Significance was set at 5% (P < 0.05).

RESULTS

Serum chemistry, blood count and peripheral blood smears, electrolytes, and urinary parameters were all within the normal range for the rat. Histologic sections of the surgically augmented zone between the bladder and uterine horn demonstrated urothelial epithelization, providing adequate coverage of the transition area in 72.22% of the rats that underwent hysterocystoplasty.

CONCLUSIONS

The hysterocystoplasty was technically viable in all the cases and proved to be an easy and safe surgical model for bladder reconstruction. All animals were healthy after surgery and all systemic parameters analyzed were within normal physiologic range for the rat.

Rat Bladders Augmented with a Novel Bovine Pericardium-Derived Biomaterial Reconstruct Functional Tissue Structures

OBJECTIVES

To determine if rat bladders augmented with an acellular Japanese bovine pericardium-derived biomaterial (CardioDISC [CD]) could support bladder reconstruction, and increase bladder volume and compliance.

METHODS

Female Sprague-Dawley rats were randomly divided into three groups (n = 5 each). After partial cystectomy, bladders were closed without augmentation (non-augmentation) or augmented with porcine small intestinal submucosa (SIS) or CD, both of which are acellular. At 1, 2, 4 and 8 weeks after surgery, bladder volume and compliance were measured. The bladders were then analyzed by immunohistochemistry for smooth muscle actin (SMA), urothelium uroplakin III (UPIII), and nerve fiber S100.

RESULTS

At 4 weeks after augmentation, the SMA-positive cells from the host bladder tissues were present near the regions augmented with CD. In addition, S100-positive cells were present within the CD-augmented tissues. At 8 weeks after surgery, the CD-augmented tissues contained layered SMA-positive cells, urothelium uroplakin III -positive urothelium, and S100 fibers, similar to normal bladder tissue. The SIS-augmented bladders showed similar results. At 8 weeks after augmentation, the bladder volume of CD-augmented bladders was larger than that at 4 weeks, while the SIS-augmented bladders were the same as those at 4 weeks. The bladder volume of the non-augmented group did not increase. The bladder compliance of the CD-augmented bladders at 8 weeks was significantly higher than at earlier times. The bladder compliance of neither the non-augmented nor the SIS-augmented groups increased during the study period.

CONCLUSION

Acellular bovine pericardium-derived material could be a suitable biomaterial for bladder augmentations.