Paul C. Stein

Epithelial Dysfunction in Nonbacterial Cystitis (Interstitial Cystitis)

Traditional concepts of impermeability of the bladder have centered around unique cellular tight junctions and ion pumps. However, recent data from our laboratory have shown that the bladder epithelium in animals and humans relies primarily on its surface glycosaminoglycans to maintain its impermeability. This study demonstrates the first disease associated with an epithelial dysfunction of the bladder, that is a leaky epithelium. The study consisted of 31 normal subjects and 56 individuals with interstitial cystitis. Interstitial cystitis patients were shown to have a leaky epithelium by placing a solution of concentrated urea into the bladder and measuring the absorption. The normal subjects absorbed 4.3% in 45 minutes, while the interstitial cystitis patients absorbed 25% (difference is highly significant, p less than 0.005). Interstitial cystitis patients with Hunners ulcers (10) had a 34.5% absorption rate, while those without ulcers absorbed 22.8% (46). This difference also was highly significant (p = 0.002) and supports the concept that patients with ulcers have clinically worse disease.

Subclinical infection of the silicone breast implant surface as a possible cause of capsular contracture

In order to reexamine the possible association between bacterial presence and capsular contracture, 55 silicone devices (mammary implants or tissue expanders) were cultured at the time of their removal from 40 patients. Special culture techniques were used in an attempt to recover bacteria adhering to the smooth-surfaced implant and encased in glycocalyx biofilm. Bacteria were detected on 56% (15 of 27) of implants surrounded by contracted capsules and on 18% (5 of 28) of those without capsular contracture (p < 0.05). Only three implants tested positive using routine plating techniques. The predominant isolate was Staphylococcus epidermidis. The concept that capsular contracture is associated with subclinical infection of silicone implants is supported by this study. With changes in the microbiological technique, bacterial recovery and growth occurs at a frequency greater than previously thought.

BLADDER INJURY MODEL INDUCED IN RATS BY EXPOSURE TO PROTAMINE SULFATE FOLLOWED BY BACTERIAL ENDOTOXIN

PURPOSE A bladder injury model was developed using protamine sulfate (PS) and endotoxin lipopolysaccharide (LPS) administered intravesically to female Sprague-Dawley rats. MATERIALS AND METHODS Experimental and control animals were catheterized and intravesically exposed to PS-LPS, PS, LPS, or phosphate buffered saline. After 4, 24 or 72 hours, rats were sacrificed. Urines and bladder tissues were then obtained. Bladder mucosal permeability was evaluated by measuring 14C-urea uptake 24 hours after injury. Repeated instillations of PS/LPS were also made in another group of rats over a period of 5 weeks to attempt to establish a more serious mucosal injury, possibly reflected by altered staining of the collagen IV component of the urinary basement membrane (UBM). RESULTS Histological examination of the tissues indicated a maximal inflammatory response in the mucosa 4 hours after instillation of PS/LPS. Neutrophils and macrophages in close proximity to the UBM and intraepithelially could be demonstrated. Bladder permeability was significantly altered (26.9% 14C-urea uptake) in rats assayed 24 hours after the PS/LPS treatment, but not after exposure to PS or LPS alone (11.9 and 17.5%, respectively). Protease activity detected in urines from experimental, but not control, animals coincided with the appearance of inflammatory cells in the lamina propria. Inflammatory injury did not appear to alter the collagen IV staining of the UBM. CONCLUSIONS This rat bladder injury model is useful for examining controversial issues regarding bladder wall structure-function alterations induced by inflammation and possibly important in the pathobiological mechanisms involved in some patients with interstitial cystitis.

Elevated urinary norepinephrine in interstitial cystitis

OBJECTIVES To measure urinary catecholamines and determine the extent to which they may be elevated in urine from patients with interstitial cystitis (IC). METHODS Random urine samples from patients with IC (n = 111) and urine from normal volunteers (n = 92) were acidified on collection (voided and catheterized specimens) and assayed for catecholamine (norepinephrine or normetanephrine) by enzyme-linked immunosorbent assay. Creatinine levels in these urine samples were also measured. RESULTS Analysis of the data indicated that patients with IC had a higher urinary level of the neurotransmitter norepinephrine compared with the measured levels in the urine of normal volunteers (89.1 +/- 58.3 versus 54.9 +/- 37.1 microg/g creatinine, P <0.05). The metabolite normetanephrine was similar in the urine samples from these two groups. Urine from patients with bladder outlet obstruction (n = 11) did not have elevated amounts of urinary norepinephrine. The norepinephrine levels were not statistically different in the urine samples from patients with symptomatic and asymptomatic IC. The elevated urinary levels in patients with IC did not decrease after treatment with sodium pentosanpolysulfate (Elmiron), heparinoids, dimethyl sulfoxide, or combinations of these during 1 to 15 months of treatment. CONCLUSIONS Norepinephrine was found to be elevated in the urine from patients with IC compared with urine from normal controls. This would be consistent with increased sympathetic (adrenergic) activity from the bladders of patients with IC or possibly from increased adrenal activity, since stress is associated with symptom increase in some patients with IC. Norepinephrine levels did not decrease with treatment nor did they differ between symptomatic and asymptomatic patients at the time of urine collection.

A new method for cytodestruction of bladder epithelium using protamine sulfate and urea

Bladder epithelium relies primarily on the presence of a surface glycosaminoglycan (GAG) layer and the structural integrity of cell-cell contact to maintain impermeability to toxic urinary wastes. Previous clinical studies evaluating bladder permeability characteristics in interstitial cystitis patients had indicated that epithelial desquamation occurs after treatment with protamine sulfate (PS) followed by hypertonic urea. The following study was performed using rabbits to further investigate this finding. The urinary bladder was evaluated for optimal treatment conditions for epithelial removal. Protamine sulfate (1 to 10 mg./ml.) and urea (100 to 200 gm./ml.) were instilled into the bladder at volumes ranging from 5 to 60 ml. to that required for near maximum distention. After incubation at room temperature for 15 minutes, the bladders were fixed and evaluated histologically for epithelial removal. The maximum epithelial removal occurred when the bladders were distended, and when PS concentration was 5 to 10 mg./ml. and urea at 200 gm./l. There was greater epithelium removal after repeated treatments. Epithelial cells that were removed were not viable based on Trypan blue staining. There was no significant increase of C14 labeled urea in the plasma after 15 minutes. Rabbits that were followed for 6 weeks after treatment did not show any histological evidence of increased collagen deposition and/or fibrosis. This procedure may have important clinical value since it may remove sufficient bladder epithelium in patients with transitional cell carcinoma to have therapeutic benefit. This offers a realistic option for selective, nontoxic destruction of bladder epithelium.

Toxic factors in human urine that injure urothelium

Aim:  Loss of the lower urinary permeability barrier and passive potassium cycling into tissue are an initiating event in interstitial cystitis. We tested whether a low molecular weight cytotoxic fraction from normal urine causes sensitivity to intravesical potassium in rats and whether the sulfated anionic polysaccharide pentosan polysulfate can neutralize this fractions cytotoxic activity.

Urothelial cytoprotective activity of Tamm-Horsfall protein isolated from the urine of healthy subjects and patients with interstitial cystitis.

Purpose : Tamm–Horsfall protein (THP) is a ubiquitous urinary protein with essentially no known function. We propose that THP is a cytoprotective agent that protects the urothelium from cationic species. To test this hypothesis we isolated THP from normal and interstitial cystitis urine to see if it could protect cultured cells from damage induced by the polyamine, protamine sulfate (PS).

Protamine sulfate and vancomycin are synergistic against Staphylococcus epidermidis prosthesis infection in vivo.

We have previously demonstrated that the quaternary amine, protamine sulfate (PS), is bactericidal against Staphylococcus epidermidis. In an attempt to decrease genitourinary prosthesis infection rates, we examined the ability of PS as a wound irrigant to inhibit Staphylococcus epidermidis viability. Eighty-seven Sprague-Dawley rats were studied by implanting a sterile silicone pellet in their dorsum. The pellet was inoculated with Staphylococcus epidermidis and the rats were divided into four groups based on the wound irrigant employed after inoculation: (1) control (sterile water) (2) vancomycin; (3) PS; (4) vancomycin + PS. All rats received perioperative and daily intramuscular vancomycin, and the pellets were explanted on postoperative day 28 and cultured. The infection rates were: (1) control 77%, (2) vancomycin 50%, (3) protamine sulfate 67%, and (4) protamine sulfate and vancomycin 19%. The differences between (2) vancomycin versus (4) vancomycin + PS and (3) PS versus (4) vancomycin + PS were significant (p = 0.05 and p < 0.005). The data suggest that PS potentiates vancomycin as a wound irrigant in prosthesis implantation.

Prevention of Acrolein-Induced Bladder Injury by Pentosanpolysulfate

The active metabolite of cyclophosphamide, acrolein, which is capable of damaging the transitional epithelium of the bladder, was evaluated in both in vivo and in vitro models to determine if its damaging effect could be reduced by the presence of a sulfated polysaccharide pentosampolysulfate. It was discovered that in all models pentosanpolysulfate was capable of reducing transitional cell injury due to acrolein.

Intestinal de-epithelialization and augmentation cystoplasty: an animal model.

OBJECTIVES An animal model of augmentation cystoplasty was developed in New Zealand rabbits to study the effects of intestinal de-epithelialization on subsequent re-epithelialization by bladder urothelium. METHODS Twenty-four rabbits underwent augmentation cystoplasty using intestinal segments that were either treated with protamine sulfate and urea solution or else anastomosed with an intact epithelium. Half of the rabbits receiving the de-epithelialized intestinal segments were subjected to glycosaminoglycan replacement therapy by administration of intravesical heparin. Experimental and control rabbits were sacrificed at 1-, 2-, and 3-month intervals. RESULTS Histologic examination of the augmented sections showed small areas of urothelium growing over the intestinal epithelium (approximately 15%). The heparin-treated group demonstrated the greatest amount of re-epithelialization. There was no obvious histologic difference in the amount of collagen present in the augmented tissues in any of the experimental groups. CONCLUSIONS In a preliminary study, New Zealand rabbits appear to be satisfactory as an experimental animal for studying the augmentation cystoplasty procedure and for the development of therapeutic interventions for enhancing epithelial growth. Protamine and urea will de-epithelialize the bowel and heparin may promote epithelialization of augmented intestinal segment by transitional epithelium.