The significance of the difference in bacterial adherence between bladder and ileum using rat ileal augmented bladder

Metabolic complications of urinary intestinal diversion

Patients with a urinary bladder malignancy or severe anatomical/functional bladder abnormalities may be candidates for urinary diversion at the time of cystectomy. Most urinary diversions are constructed from intestinal segments. Urological surgeons who perform urinary diversion surgery should be aware of the physiological and metabolic changes that can occur when intestinal segments are in direct contact with urine. The complications associated with urinary diversion are both acute and chronic. The most important factor associated with the development of metabolic complications following urinary diversion is the length of time that the urine is in contact with the bowel and the type of bowel segment used for urinary diversion. In this review, we describe the metabolic complications associated with urinary diversion, their characteristic clinical presentation, follow-up, and specific treatment.

Ileocystoplasty in rats: metabolic, renal and enteropatch changes in a mid- and long-term follow-up

INTRODUCTION

Bladder augmentation predisposes humans to many metabolic, renal and enteropatch changes. Our aim was to evaluate in a rat model of ileocystoplasty mid- and long-term urinary, metabolic, renal and graft changes.

MATERIALS AND METHODS

We performed an ileocystoplasty and a sham operation in 30 rats. Seven augmented rats and 3 sham-operated animals were euthanized after 1, 3 and 6 months. We performed urinalysis, urine culture and blood sampling for serum electrolytes and urea. Histopathological changes of the ileal patch and kidneys were also evaluated.

RESULTS

The urine cultures were positive in 14.3, 57 and 71%, respectively, 1, 3 and 6 months after surgery. Urinary pH, serum chloride and urea of the augmented group were significantly higher. Bladder calculi were formed in 23.8% of ileocystoplasty. Histopathological examination showed urothelialization of the graft with hyperplastic/metaplastic changes. The kidneys showed glomerular depletion and a marked distal tubular ectasia.

CONCLUSIONS

Our data showed that, in a mid- and long-term follow-up, rat bladders subjected to ileocystoplasty displayed hyperchloremic metabolic acidosis, electrolyte imbalance, enhanced serum blood urea levels and glomerular/tubular changes. Hyperplastic and/or metaplastic changes at the junctional zone were observed. Our experimental results suggest that frequent monitoring of renal function and surveillance of humans who have undergone ileocystoplasty are recommended.

The impact of decreasing urinary IgA levels on decreased bacteriuria in a rat model of ileal augmented bladder

PURPOSE

Bacteriuria is frequently observed in patients with urinary tract reconstruction using intestinal segments. These patients have higher urinary IgA levels than those with a normal bladder. We examined the relationship between bacterial adherence and urinary IgA in a rat ileal augmented bladder model.

MATERIALS AND METHODS

Rat ileal augmented bladder models were divided into groups 3 months and 1 year after surgery. Experimental cystitis was induced in the 2 groups by transurethral inoculation of Escherichia coli. At 14 days after inoculation the rats were sacrificed, and cfu/mg tissue of the bladder and ileal patch was measured. Rats with negative urine culture in the 2 groups were sacrificed, and urine specimens and augmented bladder tissue were collected. Urinary IgA levels were determined and immunohistochemistry staining of the tissue was done with anti-rat IgA antibody.

RESULTS

In rats with experimental cystitis E. coli significantly adhered to the bladder and ileal patch in the 3-month group but not in the 1-year group. Urinary IgA levels in the 3-month group were significantly higher than in the 1-year group. On immunohistochemistry the number of IgA immunoreactive cells in the ileal patch decreased in the 1-year group compared to that in the 3-month group.

CONCLUSIONS

These results suggest that increased urinary IgA may be the cause of the higher incidence of bacteriuria in patients with urinary reconstruction using intestinal segments. Therefore, the decrease in IgA production in the inserted intestinal segments may contribute to a spontaneous decrease in of bacteriuria with time.

Urinary Diversion

A consensus conference convened by the World Health Organization (WHO) and the Société Internationale d'Urologie (SIU) met to critically review reports of urinary diversion. The world literature on urinary diversion was identified through a Medline search. Evidence-based recommendations for urinary diversion were prepared with reference to a 4-point scale. Many level 3 and 4 citations, but very few level 2 and no level 1, were noted. This outcome supported the clinical practice pattern. Findings of >300 reviewed citations are summarized. Published reports on urinary diversion rely heavily on expert opinion and single-institution retrospective case series: (1) The frequency distribution of urinary diversions performed by the authors of this report in >7000 patients with cystectomy reflects the current status of urinary diversion after cystectomy for bladder cancer: neobladder, 47%; conduit, 33%; anal diversion, 10%; continent cutaneous diversion, 8%; incontinent cutaneous diversion, 2%; and others, 0.1%. (2) No randomized controlled studies have investigated quality of life (QOL) after radical cystectomy. Such studies are desirable but are probably difficult to conduct. Published evidence does not support an advantage of one type of reconstruction over the others with regard to QOL. An important proposed reason for this is that patients are subjected preoperatively to method-to-patient matching, and thus are prepared for disadvantages associated with different methods. (3) Simple end-to-side, freely refluxing ureterointestinal anastomosis to an afferent limb of a low-pressure orthotopic reconstruction, in combination with regular voiding and close follow-up, is the procedure that results in the lowest overall complication rate. The potential benefit of "conventional" antireflux procedures in combination with orthotopic reconstruction seems outweighed by the higher complication and reoperation rates. The need to prevent reflux in a continent cutaneous reservoir is not significantly debated, and this should be done. (4) Most reconstructive surgeons have abandoned the continent Kock ileal reservoir largely because of the significant complication rate associated with the intussuscepted nipple valve.

Urinary Tract Infections in Patients With Urinary Diversion

Several surgical techniques have been used to provide urinary diversion after radical cystectomy. The noncontinent type of urinary diversion (using an intestinal conduit) and the continent urinary diversion (ureterosigmoidostomy or construction of an intestinal pouch that serves as a deposit of urine) were used commonly in the past, leading to a cumulative considerable number of patients encountered in clinical practice. The orthotopic urinary diversion (neobladder) has been used widely during the last years. The incidence and characteristics of urinary tract infection in patients with different types of urinary diversion are reviewed. Clinicians should be aware that urinary tract infection is a frequent cause of fever in patients with urinary diversion because it occurs in a significant proportion. In addition, symptoms from the lower urinary tract may not be prominent in this population.

Global analysis of gene expression profiles in ileum in a rat bladder augmentation model using cDNA microarrays

BACKGROUND

The objective of the present study was to globally characterize the changes in the gene expression profile in the ileum after long-term urine exposure in a rat ileal augmented bladder model using cDNA microarrays.

METHODS

Bladder augmentation using the ileum was performed in female 8-week-old rats. The ileal epithelia used for bladder augmentation were harvested 1 and 3 months postoperatively and changes in the gene expression in these tissues were compared with that of intact ileal epithelia from sham-operated rats using cDNA microarrays consisting of 1176 rat genes.

RESULTS

Marked changes in gene expression in the ileum used for bladder augmentation were observed for 30 genes (16 up-regulated and 14 down-regulated genes). The differentially expressed genes include those associated with signal transduction, cell adhesion and stress response. Subsequent evaluation of changes in two randomly selected genes from the 30 differentially expressed genes by semiquantitative reverse transcription-polymerase chain reaction demonstrated the reliability of the present cDNA microarray analyses.

CONCLUSION

The present experiments identified an extensive list of genes differentially expressed in the ileum after bladder augmentation, providing valuable information for the pathophysiological assessment of patients who undergo urinary reconstruction and representing a source of novel targets for treating complications after urinary diversion.

Characterization of Escherichia coli strains causing urinary tract infections in patients with transposed intestinal segments

PURPOSE

Transposition of intestinal segments into the urinary tract predisposes to urinary tract infections. We characterized bacterial infections in these patients and examined the virulence genotype and persistence of Escherichia coli isolates.

MATERIALS AND METHODS

We followed 26 patients who underwent bladder reconstructive surgery using transposed intestinal segments. E. coli strains isolated from the urine of these patients were genotyped for established virulence determinants and the frequency of carriage was compared with E. coli strains isolated from community acquired urinary infections and the fecal flora of anonymous volunteers. A longitudinal study of E. coli strains in 9 patients was also done using pulsed field gel electrophoresis.

RESULTS

E. coli was the most frequently isolated organism, responsible for 59% (62 of 105) of monobacterial infections. Other bacteria isolated included Klebsiella species, Proteus species and Enterococcus faecalis. Community acquired E. coli strains were more likely to carry multiple determinants for particular adhesins (P and S fimbriae) and toxins (alpha-hemolysin and cytotoxic necrotizing factor) than fecal strains. Carriage frequency for bladder reconstruction strains was intermediary and not significantly different. The key finding was that E. coli strains persisted for prolonged periods, including 2 years in certain patients, often despite various antimicrobial treatments.

CONCLUSIONS

This study highlights that further steps must be taken to prevent and treat urinary tract infections in this susceptible group. Particular attention should be given to the treatment of persistent infections.

Changes in sodium transport in epithelial cells in a rat ileal-augmented bladder model

OBJECTIVE

To investigate changes in the morphology and sodium transport ability of intestinal epithelium diverted to the urinary tract, using an in vitro sodium-binding benzofuran isophthalate (SBFI) technique, as the effects of long-term urine exposure on the transport of electrolytes through intestine are incompletely understood.

MATERIALS AND METHODS

Ileal augmentation cystoplasty was conducted in female Sprague-Dawley rats; at 3 and 12 months after surgery the serum concentration of sodium, chloride and potassium were measured. Sodium transport in the ileal epithelial cells diverted to the urinary tract was evaluated using SBFI, as the value of the 340/380 nm excitation ratio measured with fluorescence spectrophotometry. The villous height and the number of villi per ileal length were obtained from haematoxylin and eosin-stained sections.

RESULTS

After 3 months the mean (sd) serum sodium concentrations in normal and augmented rats were 140.4 (2.5) and 140.7 (3.5) mmol/L, respectively; the chloride concentration in normal rats was 97.0 (2.9), and in augmented rats at 3 and 12 months it was 102.4 (2.9) and 99.0 (3.7) mmol/L, respectively. At 3 months, chloride concentrations were significantly higher in augmented than in normal rats (P < 0.05). The mean (sd) 340/380 nm ratio increased by 0.85 (0.09) in the normal ileum, and by 0.73 (0.15) and 0.49 (0.23) in the ileum of augmented rats at 3 and 12 months, respectively; the difference between normal and augmented ileum at 12 months was significant (P < 0.05). At 12 months the villous height in the augmented ileum, at 227.6 (16.0) micro m, was significantly less than in the normal ileum, at 803.4 (66.2) micro m (P < 0.05). However, the number of villi/mm ileum in normal and augmented rats at 12 months was 13.7 (1.5) and 15.0 (0.8), respectively, and not significantly different.

CONCLUSION

Sodium transport decreased significantly after long-term exposure to urine; the improvement in metabolic change was probably attributable to alterations of electrolyte transport and atrophic changes of the villus.