Morphologic changes in ileal reservoir mucosa after long-term exposure to urine. A study in patients with continent urostomy (Kock pouch)

Insight into long-term histological, proliferative and apoptotic modifications in ileal orthotopic neobladder and conduit mucosa

Aims and background

To assess the long-term histological, apoptotic and proliferating alterations of the intestinal mucosa of ileal conduits and orthotopic neobladders.

Methods

Fifty patients (46 males, 4 females), aged 52–78 years, who underwent urinary diversion with either ileal orthotopic neobladder (group ON, 20 patients) or conduit (group IC, 30 patients) from 2001 to 2005, were included in this prospective study Ileal samples were collected during surgery (controls) and by random mucosal biopsies 6, 12, 24, 36 and 48 months later. Histological (villi height, crypt depth, eosinophil cell count), proliferation (Ki67 immunochemistry), and apoptotic (Bcl-2 immunochemistry TUNEL) parameters were assessed.

Results

During the 4-year follow-up, we recorded progressive villi area, height and crypt depth reduction, mucosa flattening, and inflammatory and eosinophilic infiltration. Villi height: crypt depth ratio showed a statistically significant difference ( P <0.05) between the two groups from the 6th month. Dysplasia, metaplasia, and neoplasia were not observed. Bcl-2 values showed a progressive increase until 24 months in group ON and 12 months in group IC, followed by a decline thereafter. Ki-67 values showed a progressive increase after 6 months in group ON and an increase until 24 months followed by a decline thereafter in group IC. TUNEL showed two peaks, at 24 and 48 months.

Conclusions

Histological adaptation was revealed in both groups, with statistically significant differences in favor of orthotopic substitution. Proliferative and apoptotic pathways are implicated as demonstrated by relevant modifications of Bcl-2, Ki-67 and TUNEL, in accord with the histological adaptation.

Interindividual variability in the absorption of ciprofloxacin and hydrocortisone from continent ileal reservoir for urine

OBJECTIVE

The neobladder created with a detubularized segment of ileum as standard treatment for the transitional cell carcinoma of the bladder may permit absorption of drugs. As a consequence, on the one hand the elimination of drugs excreted in the urine may be delayed and a change of dosage may be required, and on the other hand the intravesical administration of a drug may produce blood levels capable of inducing unwanted systemic effects. The purpose of the present study was to explore the possibility of drug absorption from a continent ileal reservoir for urine.

METHODS

The possibility of drug re-absorption from a continent ileal reservoir for urine was studied in 12 patients with well functioning reservoirs after a time interval of 3 months from surgery and also, in 7 of them, 6 months later. Saline solutions of ciprofloxacin or hydrocortisone were instilled and maintained in the reservoir for 2 h, and drug concentrations in plasma were measured 1 and 2 h after instillation.

RESULTS

Both ciprofloxacin and to a lower extent hydrocortisone were adsorbed from the reservoir, but with large interindividual variability. A comparison of the plasma concentrations produced by the two drugs 3 and 9 months after creation of the new bladder revealed that after 9 months the absorption was decreased in 3 patients, substantially unchanged in 2, and increased in 2.

CONCLUSIONS

The results of this study show that both ciprofloxacin, chosen for its use as possible radiosensitizing agent in bladder cancer patients, and hydrocortisone, chosen as an example of lypofilic endogenous compound, can be absorbed through the intestinal mucosa of a continent ileal reservoir, but to a different extent and with high interindividual variability.

Luminal nitric oxide in ileal reservoirs for continent cutaneous diversion or orthotopic bladder reconstruction

OBJECTIVES

To measure mucosal inflammation as reflected in nitric oxide (NO) production in ileal reservoirs for the storage of urine and to correlate it with the growth of bacteria as well as CRP.

METHODS

Intraluminal gas NO concentrations were determined using the chemoluminescence technique in 25 patients with continent cutaneous ileal reservoirs (Kock pouch) and 12 patients with orthotopic bladders (hemi-Kock or T-pouch). NO concentrations were determined in both intestinal reservoir gas and silicon catheter balloon gas. Urinary culture and blood CRP determinations were performed.

RESULTS

NO concentrations in reservoir gas were higher than in silicon catheter balloons. Bacteriuria was associated with approximately 20 times higher NO concentrations than sterile urine. NO concentrations did not differ between continent cutaneous reservoirs or orthotopic bladders when due attention was paid to variance in the rate of bacteriuria. Elevated CRP was associated with higher NO concentrations. Bacteriuria with acinetobacter, enterococci and pseudomonas appeared to cause comparatively lower NO concentrations. The inflammatory response of reservoir walls to bacteriuria did not decrease with time.

CONCLUSIONS

Urine in itself causes much less intestinal wall inflammation than bacteriuria, as reflected in NO production. High CRP values are associated with high NO concentrations. The inflammatory response varies with the bacterial specimens.

Histopathologic changes in the mucosa of ileal orthotopic neobladder--findings in 24 patients followed up for 5 years

OBJECTIVE

To evaluate changes occurring in the mucosa of the neobladder over a period of 60 months in 24 patients with orthotopic ileal neobladder.

MATERIALS AND METHODS

A total of 36 male patients have undergone radical cystoprostatectomy and received an orthotopic ileal neobladder in our hospital during the last 10 years; 24 of these patients, all of whom completed a follow-up period of 60 months, are included in this study. All cases underwent a biopsy of the ileal mucosa at the time of surgery and their neobladder mucosa was then biopsied at 6, 12, 24, 36 and 60 months. The specimens were stained with hematoxylin-eosin in order to examine the changes in the thickness of the mucosa and its villi. Sections were also stained with Alcian blue and periodic acid-Schiff in order to determine the number of goblet cells. A morphometric scoring system was created to quantify the change in villi size.

RESULTS

The mean thickness of the ileal mucosa at the initial biopsy was 270.9 +/- 35.9 microm and displayed a continuous decrease at all of the subsequent biopsies. The number of luminal goblet cells increased during follow-up. Villus atrophy was found to be a continuous process during follow-up. No dysplasia or malignancy was detected in any of the biopsies.

CONCLUSION

During a follow-up period of 5 years, there were no neoplastic changes in our patients, but instead a protective response of the mucosa to its new environment was observed.

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.

Permeability of intestinal mucosa from urinary reservoirs in man and rat

OBJECTIVE

To evaluate the barrier properties of intestinal mucosa chronically exposed to urine and to evaluate possible differences between ileal and colonic segments used in the reconstruction of the urinary tract.

MATERIALS AND METHODS

Mucosal specimens from patients with continent reservoirs with an abdominal stoma, or orthotopic neobladders constructed from colonic segments, were obtained at revisional surgery. Control segments were obtained during right-sided hemicolectomy. In addition, ileal and colonic segments from enterocystoplasties in rats were assessed. The mucosa-to-serosa passage of marker molecules, i.e. (14)C-mannitol, (3)H-glucose, fluorescein isothiocyanate-dextran 4400 and ovalbumin, was measured using modified Ussing diffusion chambers.

RESULTS

In man, there were no permeability differences between segments exposed to urine and control segments for any of the marker molecules. In rats, there was less passage of markers in ileal and colonic transplanted segments than in intestinal segments from sham-operated animals.

CONCLUSIONS

Intestinal mucosa that has been in chronic contact with urine maintains its barrier function; in the rat model the permeability was even decreased. In addition, there were no detectable differences between ileal and colonic segments in this model.

Isolation of human intestinal defensins from ileal neobladder urine

We describe the isolation of naturally occurring human intestinal defensins HD-5 and HD-6 from ileal neobladder urine and ileal mucosa. Using an antibody-based detection assay, we found multiple N-terminally processed forms of HD-5. The predominant HD-5 forms in tissue were longer than those in neobladder urine (amino acid (aa) 23-94 and 29-94 versus aa 36-94, 56-94 and 63-94) suggesting that Paneth cells store prodefensin that is processed to mature defensin during or after degranulation. Search for mature HD-6 yielded aa 69-100 as the predominant form in both sources. The ileal neobladder is a promising model to study human Paneth cell secretion.

Inhibition of transport processes of intestinal segments following augmentation enterocystoplasty in rats

PURPOSE

Sodium and chloride transport was measured by using the Ussing chamber-voltage clamp technique to evaluate alterations occurring in ileal segments interposed in the urinary tract in a rat enterocystoplasty model.

MATERIALS AND METHODS

In adult male Sprague-Dawley rats which had undergone augmentation ileocystoplasties 3 months earlier, intestinal segments were explanted from the neobladders and native ileal segments were removed separately for electrolyte transport and morphometric analysis.

RESULTS

Basal ileal active sodium and chloride absorption and cyclic nucleotide-induced chloride secretion were attenuated in transplanted ileum in contrast to control tissue. Morphologically, there was villus epithelial hyperplasia, crypt hyperplasia and chronic inflammation in transplanted segments, but villus height:crypt length ratios were unchanged.

CONCLUSIONS

Pathophysiologic derangements in intestinal segments interposed in the urinary tract include inhibition of sodium and chloride transport processes and mucosal hyperplasia. The use of the Ussing chamber/voltage clamp technique described herein offers a new approach for additional studies of the metabolic consequences following urinary diversion.

Urinary immunoglobulins in patients with continent urinary reservoirs and ileal conduits

BACKGROUND

Although bowel segments are commonly used for reconstructing the urinary tract, a high incidence of bacteriuria is observed in patients with urinary intestinal diversion. The normal gastrointestinal tract possesses a potent mucosal immune system characterized by secretory immunoglobulin A (sIgA) as the major humoral defense factor. However, the significance of urinary IgA secretion as the mucosal defense mechanism in patients with urinary intestinal diversion has remained obscure. In this study, urinary levels of sIgA as well as serum-type IgA were measured in patients with continent urinary reservoirs (Kock and Indiana pouches) and ileal conduits.

METHODS

Twenty-four-hour urine samples were collected in a total of 80 patients with urinary intestinal diversion (22 Kock pouch patients, 21 Indiana pouch patients and 37 ileal conduit patients). The amount of sIgA and serum-type IgA were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Urinary IgA levels showed great inter- and intra patient variability in all three groups. Indiana reservoir urine contained significantly greater amounts of sIgA (mean 32.0 mg/24 hrs) than Kock reservoir urine (11.9 mg) and conduit urine (4.9 mg), whereas Kock reservoir urine contained significantly more sIgA than conduit urine. However, the corresponding difference was not observed in regard to serum-type IgA. In none of the three modes of urinary diversion did 24-hour sIgA excretion show any correlation with the length of time after surgery.

CONCLUSIONS

Since the amounts of sIgA in these patients were much greater than reported in urinary tract infection as well as in normal subjects, the major portion of urinary sIgA seemed to be secreted by the intestinal segments. Long-term sIgA secretion in urinary intestinal diversion, especially continent urinary reservoirs, may be an important host defense system.

Effect of urinary intestinal diversion on urinary risk factors for urolithiasis

We investigated the effect of urinary intestinal diversion on risk factors for calcium urolithiasis, such as calcium, phosphate, magnesium, uric acid, oxalate and citrate, in 3 groups of patients (Kock pouch, Indiana pouch and ileal conduit). Mean urinary volume was not significantly different among the 3 groups. Mean serum creatinine and 24-hour creatinine clearance in the continent reservoir group were better than in the ileal conduit group. Mean urinary excretion of calcium, phosphate and magnesium was significantly greater in the continent reservoir group than in the ileal conduit group. Although calcium excretion had a positive correlation with 24-hour creatinine clearance, calcium excretion per ml. per minute creatinine clearance still showed a significant difference. Increased calcium excretion is considered to reflect metabolic disturbances resulting from reabsorption of urinary solutes through the intestinal segments. Overall, there was no significant difference in the urinary parameters between the Kock and Indiana pouch groups. While mean urinary oxalate and citrate were within the normal range in all 3 groups, more than a third of the patients in each group were hypocitraturic (less than 100 mg. per day). In none of the 3 groups did the levels of urinary calcium, phosphate and magnesium, as well as other urinary risk parameters show any correlation with the duration of diversion. In summary, our study indicated that the continent urinary reservoir causes a long-term increase in urinary excretion of calcium, phosphate and magnesium. These urinary metabolic alterations might promote the formation of calcium urolithiasis as well as infectious stones. The degree of metabolic alterations may be greater with a continent reservoir than with an ileal conduit.

Morphological analysis of ileal grafting following ileocystoplasty in the rat: a kinetic and ultrastructural study of the intestinal epithelium

Ileocystoplasty was performed in rats and the morphological and cell-kinetic changes occurring in the ileal grafts were determined at intervals up to 18 months postoperatively. The intestinal mucosa underwent no progressive changes but included villous and avillous regions associated with crypts of various sizes at all time intervals. Newly appearing and densely packed epithelial cells, shaped like petals, were always present in the lower parts of the villi associated with crypts showing no elongation, but seldom present in those with elongated crypts in the villous mucosa. Bromodeoxyuridine studies showed that the petal-shaped cells interfered with cell migration. No petal-shaped cells were observed in avillous mucosa in which the rate of cell turnover depended on crypt size. Fine-structural changes in absorptive epithelial cells in both types of mucosa included features of prematurity or hypermaturity in the cytoplasm and close adherence to the basal portions of adjacent cells and to the basal lamina. These changes may possibly contribute to the prevention of reabsorption of urine. However, some of the mechanisms responsible for adherence of the basal parts might incidentally interfere with the normal cell kinetics of the intestinal epithelium, resulting in dense packing of cells and the formation of multiple types of mucosa in ileal grafts.

Crypt cell thymidine incorporation in ileal urinary pouch. Preliminary report

This is a brief communication about mucosal change in ileal urinary reservoirs, the earliest reported observations to date. Previous authors described early villous atrophy and crypt elongation, late panmucosal atrophy and metaplasia. Crypt cell proliferation should be a forerunner of these events and therefore warrants quantitative measurement. We studied continent pouches in dogs on postoperative days 42 and 43 using in vivo tritiated thymidine incorporation into crypt cell DNA, a novel application of autoradiography for urinary reservoirs. Adjacent normal ileum provided the internal control. Increased crypt cell thymidine incorporation was confirmed at this early time.

Structure of mucosa in continent ileal reservoirs 15 to 19 years after construction

Mucosa biopsy specimens were obtained from 12 patients with continent ileostomy reservoirs constructed 15 to 19 years previously. Biopsies from normal ileal mucosa, taken from six other patients with no apparent bowel disease, served as controls. The specimens were processed for light and electron microscopy. The reservoir mucosae showed an increased amount of inflammatory cells, but there were no signs of dysplasia. In the goblet cells, sialomucins dominated over sulfomucins; in this respect no difference was found between reservoirs and controls. Morphometric studies showed an increase of mucus-storing goblet cells in the reservoir mucosae, both with regard to relative number and to volume density. The mitotic index was higher than normal in the reservoirs, but the relative number of the Paneth cells and the height of the villus epithelial cells were similar in the reservoirs and the controls. In the reservoirs, the surface amplification factors due to villi and to microvilli (near the villus tips) were reduced by some 29% and 20%, respectively, indicating villus hypotrophy. It is concluded that only minor morphologic changes appear in the ileal reservoir mucosa 15 to 19 years after construction. Morphometry provides a sensitive tool to demonstrate such changes in intestinal morphology.

Effect of sulfate on calcium and magnesium homeostasis following urinary diversion

The present investigation was undertaken to elucidate the mechanisms of renal calcium and magnesium wastage in patients with urinary diversion through intestinal segments. Patients with urinary intestinal diversions demonstrated a hyperchloremic metabolic acidosis, increased serum sulfate and phosphate, and increased urinary excretion of calcium, phosphate, sulfate, and magnesium. A study was conducted in rats utilizing oral or intravenous loads of various solutes to investigate the possible mechanisms of these findings in patients. Ammonium enhances renal sulfate excretion and intestinal sulfate absorption. Increased filtered loads of sulfate inhibit renal tubule sodium and calcium reabsorption. Dietary ammonium and sulfate result in increased serum phosphorous concentrations. Ammonium appears to directly inhibit renal magnesium reabsorption. Renal tubule dysfunction resulting from relieved obstruction appears to enhance the inhibitory effect of sulfate on renal sodium and calcium reabsorption but does not alter the effect of ammonium on renal magnesium excretion. Taken together, these findings suggest that patients with hyperchloremic metabolic acidosis from the chronic reabsorption of ammonium chloride by intestinal urinary diversions may also reabsorb urinary sulfate. This load of ammonium and sulfate inhibits renal calcium and magnesium reabsorption.

Absorption of L-phenylalanine in human ileal reservoirs exposed to urine

The mucosa of ileal reservoirs exposed to urine undergoes successive structural changes, indicating a loss of absorptive capacity. In patients with urinary diversion via a continent ileal reservoir, the active absorption of L-phenylalanine from the reservoir was studied at different postoperative time intervals. A test solution containing L-phenylalanine was instilled into the reservoir and samples were taken at intervals during a period of one hour for determination of phenylalanine. In one group of patients, urine from the kidneys by-passed the reservoir via a catheter inserted into the afferent segment. Within three months after construction of the ileal reservoir, the uptake was significantly slower than that in ileostomy reservoirs and the absorption decreased even more with longer observation times. Mixing of urine with the reservoir contents did not influence the uptake of L-phenylalanine to any significant degree. The reduced absorption of L-phenylalanine indicates that the uptake of other substances from this type of ileal reservoirs might be decreased also.

Ultrastructural and histochemical changes in ileal reservoir mucosa after long-term exposure to urine. A study in patients with continent urostomy (Kock pouch)

Mucosal biopsy specimens were obtained from ileal reservoirs used for urinary collection in patients with continent urostomy. Shortly after construction of the reservoir there was a reduction in villous height and an increase in crypt depth. After 2 to 3 years of observation, avillous areas were noted in the reservoir mucosa, mixed with islets of villous mucosa. Specimens from the avillous areas showed a marked decrease in height of superficially located enterocytes, with loss of microvilli and a reduction in cell organelles. The histochemically demonstrable activity of oxidative enzymes was significantly reduced in the epithelial cells. There was an increase in the number of goblet cells and autonomic nerve fibres in the crypt layer. The constant exposure to urine led to significant alterations of the ileal mucosa resulting in avillous areas mixed with villous remnants in which many of the intestinal characteristics both structurally and functionally disappear.