Autologous regeneration of blood vessels in urinary bladder matrices provides early perfusion after transplant to the bladder.

Large animal testing and clinical trials using bioengineered bladder for augmentation have revealed that large grafts fail due to insufficient blood supply. To address this critical issue, an in vivo staged implant strategy was developed and evaluated to create autologous, vascularized bioengineered bladder tissue with potential for clinical translation. Pig bladders were used to create acellular urinary bladder matrices (UBMs), which were implanted on the rectus abdominus muscles of rats and pigs to generate cellular and vascular grafts. Rectus-regenerated bladder grafts (rrBGs) were highly cellularized and contained an abundance of CD31-positive blood vessels, which were shown to be functional by perfusion studies. Muscle patterns within grafts showed increased smooth muscle formation over time and specifically within the detrusor compartment, with no evidence of striated muscle. Large, autologous rrBGs were transplanted to the pig bladder after partial cystectomy and compared to transplantation of control UBMs at 2 weeks and 3 months post-transplant. Functional, ink-perfused blood vessels were found in the central portion of all rrBGs at 2 weeks, while UBM grafts were significantly deteriorated, contracted and lacked central cellularization and vascularization. By 3 months, rrBGs had mature smooth muscle bundles and were morphologically similar to native bladder. This staged implantation technique allows for regeneration and harvest of large bladder grafts that are morphologically similar to native tissue with functional vessels capable of inosculating with host bladder vessels to provide quick perfusion to the central area of the large graft, thereby preventing early ischemia and contraction.

Non-palpable testis: is management consistent and objective?

INTRODUCTION: Diagnostic laparoscopy is recommended for boys with non-palpable testis (NPT) by American and European guidelines with the decision to pursue inguinal exploration based upon testicular vessel appearance. We hypothesized that management decisions are not consistent with the guidelines, and that assessment of vessels is subjective. MATERIALS AND METHODS: Pediatric urologist management decisions were evaluated via an electronic survey to determine impact of contralateral testicle size, sonographic findings, surgeon region, and years in practice. In a digital image survey, surgeons were asked to interpret gonadal vessel status of 32 consecutive cases of NPT with absent abdominal testis as normal, atretic, or blind-ending to determine intra- and inter-rater reliability. RESULTS: Of the 339 participants, more Europeans (49%) chose sonography as the first management step for NPT compared to US surgeons (12%). Regardless of sonographic findings, over 80% chose laparoscopy as the first step. In the presence of normal, atretic, and blind-ending vessels, the decisions to proceed with inguinal/scrotal exploration were 88%, 68%, and 17%, respectively. Contralateral hypertrophy and sonography findings had no significant impact on the decision to proceed with inguinal/scrotal exploration. The visual gonadal vessel survey showed surgeon interpretation of normal or blind-ending vessels had moderate inter-rater reliability. Surgeons did not agree on normal status 37% of the time and did not agree on atretic status 66% of the time. There was no statistical difference between European and US respondents (P = 0.23). Intra-rater reliability was fair for blind-ending vessels. When the first interpretation was blind-ending, the same surgeon changed interpretation of the same image 39% of the time. There was no statistical difference by years of practice. CONCLUSIONS: Non-visualization of NPT on sonography and contralateral testis size had no significant impact upon management decisions. Surgeons chose to pursue inguinal/scrotal exploration based upon laparoscopic gonadal vessel status. However, these interpretations were subjective with low inter- and intra-rater reliability.