In Vivo Responses to Urological Biomaterials as Utilized for Urological Reconstruction


Introduction and Objectives: Biological tissues are widely used in urological surgeries to treat conditions like pelvic organ prolapse and stress urinary incontinence (SUI). In this study, we examine the in vivo responses of four such agents used clinically in urological reconstruction.

Methods: Four commercially available tissue samples were evaluated from three different companies: Small intestine submucosa (SIS) (Cookbiotech). Tutoplast Fascia lata (FL) (Mentor Corp). Tutoplast Fascia dermis (FD) (Mentor Corp) and Pelvicol (P) (C.R. Bard). The biomaterial was implanted intraperitoneally at the bladder neck of Balb/c mice. Animals were sacrificed at 2, 4, 8, or 12 weeks post-implantation. Bladder and implants were extracted and fixed for histological analysis. Tissue sections were stained for evaluation of fibrous capsule and tissue incorporation. Image analysis using image J software was performed to determine capsule thickness (mm), cell number (mm2), aspect ratio (cell morphology) and angiogenesis.

Results: Tissue extracts were recovered with no noticeable macroscopic inflammatory signs. However, the histological responses to the biomaterials were quite different. Implants from the SIS group were the only group to show a significance decrease in capsule thickness from 2 to 12 weeks of implantation (p=0.01). When examining cell number, we determined that FL and P displayed a decrease in cell number, SIS remained relatively constant and FD increased with time. Interestingly, the aspect ratio of each group was the opposite with FL and SIS having an increasing aspect ratio, while FD and P demonstrated a decreasing ratio with time. At 2 weeks, SIS showed increased number of capillaries with significant angiogenesis.

Conclusions: SIS induced a less pronounced inflammatory response. However, other antigens may be present which elicit inflammatory reactions, thus limiting the implant incorporation and use for long term urological therapies.