Long-term histological and mucin alterations in the neobladder mucosa following urinary bladder augmentation or substitution with gastrointestinal segment

Successful engraftment of bladder organoids in de-epithelialized mouse colon

PURPOSE

To engraft bladder organoids (BO) on de-epithelialized mouse colon using an epithelial replacement technique.

METHODS

BO cultured using bladder specimens from enhanced green fluorescent protein (EGFP) transgenic mice were engrafted to replace proximal colon epithelium stripped from an approximately 1 cm long target site in syngeneic wild-type recipient mice (n = 9) by exposure to ethylenediaminetetraacetic acid by infusion and flushing with phosphate buffered saline. Target sites were harvested on postoperative days 2, 7, and 28 for hematoxylin-eosin staining and immunofluorescence.

RESULTS

Histology on postoperative days 7 and 28 showed BO derived EGFP + cells forming multiple layers on the luminal surface of the colon. Immunohistochemistry showed that EGFP + areas were positive for CK5 and CK14, markers for basal and immature subtype urothelium, respectively, but negative for CA2, a marker for colonic epithelium. Ki67 was detected predominantly in the basal parts of EGFP + areas on postoperative day 7 and day 28.

CONCLUSIONS

This is the first report of successful engraftment of BO in de-epithelialized colon with urothelial tissue reconstituted by actively proliferating cells. This technique could be developed for augmentation cystoplasty to prevent bladder calculi formation and malignant transformation.

Re-evaluation of histological findings after colocystoplasty and gastrocystoplasty

INTRODUCTION

The potential of malignant transformation and its risk factors after bladder augmentation performed in childhood are still unknown. The necessity of surveillance cystoscopies and biopsies has been questioned in the past decade.

OBJECTIVE

In a previous study, the authors did not detect any malignancy after colocystoplasty (CCP) or gastrocystoplasty (GCP) during the short-term follow-up, however, various alterations of the mucosa were found. A correlation between the nature of histological changes and the frequency of bacterial colonization after CCP were also found. The authors hypothesized that a longer-term follow-up of their patients would reveal an increase in pathological change or show stronger association between the histological alteration, bacterial colonization, and/or stone formation.

PATIENTS AND METHODS

Thirty-five patients (20 cases of colocystoplasties - CCPs; 15 cases of gastrocystoplasties - GCPs) participated in the study published in 2002. All patients were followed biannually with endoscopic assessment and biopsies. Two independent pathologists, evaluated regular biopsies from the native bladder, from the segment used for augmentation and from the anastomosis line. Etiology, frequency of positive urine cultures, and stone events were recorded and compared with histological findings between groups and with the previously published results.

RESULTS

Continuous surveillance allowed the follow-up of 30 patients (CCP 19/20, GCP 11/15) for 20 and 15 years. No malignancies were identified. Results of biopsies showed significant difference between groups (summarized in the tables). Chronic inflammatory changes were found following both types of augmentations, but they were more common in the urothelium following GCP and more common in the colonic mucosa following CCP. The rate of metaplastic lesions was higher after gastrocystoplasty (GCP). Significant association was found between the etiologic factor and the nature of histological change after CCP, as metaplastic lesions occurred only in patients with bladder exstrophy. Stones occurred more frequently in exstrophy patients as well. The nature of the histological changes did not correlate with positive urine cultures in either of the groups. Significantly higher incidence of bacterial colonization and stone occurrence were found after CCP.

CONCLUSIONS

Long-term follow-up of the patients failed to reveal an increase in pathological changes, and no malignancies were observed. According to the results of this study, etiology of bladder dysfunction and the type of augmentation might influence the histological alterations after augmentation cystoplasty. The efficiency of surveillance cystoscopies and biopsies are low. The present data suggest that surveillance cystoscopy and biopsy should not be routinely performed, and should be done only if the symptoms are suspicious for malignancy.

The local microbiome after pediatric bladder augmentation: intestinal segments and the native urinary bladder host similar mucosal microbiota

INTRODUCTION

Next-generation sequencing (NGS) techniques have provided novel insights into the microbiome of the urinary bladder (UB). In children after bladder augmentation using either ileum (ileocystoplasty, ICP) or colon (colocystoplasty, CCP), the fate of the mucosal microbiome introduced into the urinary tract remains unknown.

OBJECTIVE

The aim was to compare the mucosal microbiome of the native UB vs the augmented intestinal segment (IS) using NGS.

STUDY DESIGN

Twelve children after bladder augmentation (ICP n = 6, CCP n = 6) were included. Biopsies were taken during routine postoperative cystoscopy from the native UB and the IS. Specimens underwent whole-genome DNA extraction, 16S rRNA gene amplification, NGS, and Quantitative Insights Into Microbial Ecology (QIIME) data analysis. Downstream statistical data analyses were performed in Calypso.

RESULTS

Patients' median age at the time of surgery was 11 years (6-17 years), and the median interval between augmentation and sampling was 7 years (4-13 years). α-Diversity (Shannon diversity index) was not significantly different between IS vs UB, ICP vs CCP, and male vs female. No general differences in the overall bacterial pattern (β-diversity) were found between IS, UB, ICP, and CCP groups. The groups overlapped in principal coordinate analysis (PCoA) and non-metric multidimensional scaling (NMDS) analysis (Figure). Age at sampling had a statistically significant influence on β-diversity at the genus level. Corynebacterium, Pseudoxanthomonas, Lactobacillus, Flavobacterium, and Micrococcus were the most dominating taxa detected over all samples. There was an obvious dominance of the genus Corynebacterium in the samples taken from the UB and IS in both ICP and CCP patients. Limitations of this study include the relatively small number of patients.

CONCLUSION

After bladder augmentation, the native UB and augmented ISs (ICP and CCP) host similar microbiota despite their distinct differences of originating mucosal anatomy.

Bladder augmentation in children: current problems and experimental strategies for reconstruction

Bladder augmentation is a demanding surgical procedure and exclusively offered for selected children and has only a small spectrum of indications. Paediatric bladder voiding dysfunction occurs either on a basis of neurological dysfunction caused by congenital neural tube defects or on a basis of rare congenital anatomic malformations. Neurogenic bladder dysfunction often responds well to a combination of specific drugs and/or intermittent self-catheterization. However, selected patients with spinal dysraphism and children with congenital malformations like bladder exstrophy and resulting small bladder capacity might require bladder augmentation. Ileocystoplasty is the preferred method of bladder augmentation to date. Because of the substantial long-and short-term morbidity of augmentation cystoplasty, recent studies have tried to incorporate new techniques and technologies, such as the use of biomaterials to overcome or reduce the adverse effects. In this regard, homografts and allografts have been implemented in bladder augmentation with varying results, but recent studies have shown promising data in terms of proliferation of urothelium and muscle cells by using biological silk grafts.

Transition to adulthood with a bladder augmentation: histopathologic concerns

Aim:

To investigate the histopathologic changes in native bladder and gastrointestinal segment, the relation between histopathologic changes, type of operation and the period passed over operation in patients with bladder augmentation.

Materials and methods:

Twenty consecutive patients were enrolled in this study. Histopathologic evaluation of the cystoscopic mucosal biopsies from native bladder and enteric augment was performed in all patients.

Results:

Active or chronic non-specific inflammation of various degrees was found in all specimens except two. Metaplastic changes were detected in 3 patients. Two patients had squamous metaplasia (one focal, one extensive) and one patient had intestinal metaplasia. All metaplastic changes were found in native bladder specimens. The type of augmentation in patients with metaplastic changes were ileocystoplasty and sigmoidocystoplasty. No signs of malignancy were detected in any patient.

Conclusion:

The complexity of the disorders requiring bladder augmentation does not let the surgeons to draw a clear line between different groups of complications including malignancy formation. However, due to challenging course of the augmentation procedure itself, surgeons should be well aware of the possibility of malignancy development.

Transitional metaplasia in intestinal epithelium of rats submitted to intestinal cystoplasty and treatment with L -lysine

Purpose:

To evaluated the effects of L-lysine on the intestinal and urothelial epithelia in cystoplasty in rats.

Methods:

Twenty-eight 9-week-old rats were assigned to 4 groups: Group A (n=8) cystoplasty followed by administration of L-lysine (150 mg/kg body weight by gavage) for 30 weeks; Group B (n=8) cystoplasty + water for 30 weeks; Group C (n=6) L-lysine for 30 weeks; Group D (n=6) water for 30 weeks.

Results:

On histopathology with hematoxylin and eosin, mild to moderate hyperplasia transitional was observed in at the site of anastomosis in all animals submitted to cystoplasty (Groups A and B), but "transitional metaplasia" of the intestinal glandular epithelium was more accentuated in Group A (p=0.045). No inflammatory cells, dysplasia or abnormalities were observed. Staining with Alcian blue revealed a substantial reduction of goblet cells and mucins in the colon segment (Groups A and B).

Conclusion:

The administration of L-lysine to rats accelerated the development of transitional metaplasia in the epithelium of the colon segment in cystoplasty.