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 μg/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.     

Cyto-injury factors in urine: a possible mechanism for the development of interstitial cystitis

PURPOSE: In most of our patients with interstitial cystitis (IC), the disease is associated with an increased urothelial permeability whose cause has not been identified. We postulate that both normal urine and the urine of IC patients contains factors capable of injuring the mucosa and causing an increased permeability that would allow urine components to leak into the bladder muscle. To test this hypothesis, we examined fractions of normal urine for toxic effects on bladder smooth muscle and epithelial cells in vitro. In the same in vitro system, we measured the effects of Tamm-Horsfall protein (THP), a normal urinary glycoprotein that may be a scavenger of injurious agents capable of "detoxifying" normal metabolic products. MATERIALS AND METHODS: Human urothelial cells (T24) and rabbit bladder smooth muscle cells were incubated overnight with various fractions prepared from healthy volunteers' urine. The urine fractions of molecular weights >100 Da were incubated overnight with either urothelial or smooth muscle target cells after no treatment or after heating to 56C, preincubation with THP, exposure to heparin, or elution from heparin. Cytotoxicity was determined for each group using a neutral red uptake assay. RESULTS: Urine fractions of molecular weight 500 to 1000 Da were cytotoxic to smooth muscle cells (39%) and urothelial cells (50%). Cytotoxicity levels for THP-treated fractions were significantly lower than those for untreated fractions in both urothelial cells (7% versus 89%, p <0. 001) and smooth muscle cells (8% versus 70%, p <0.01). Fractions exposed to heparin were less cytotoxic to smooth muscle cells (20%) than were untreated fractions (27%). Fractions eluted from heparin were also cytotoxic to urothelial cells (42%). CONCLUSIONS: Normal human urine contains heat labile, cationic components of low molecular weight that bind to heparin. These components, when separated from the bulk of the urinary wastes, are cytotoxic to urothelial cells as well as underlying smooth muscle cells, indicating their potential for causing bladder mucosal injury. The cytotoxic activity can be blocked by the presence of THP. This urinary cytoprotective activity of THP may play an important but unrecognized role in the development of IC.     

Urinary neutrophil chemotactic factors in interstitial cystitis patients and a rabbit model of bladder inflammation.

The present study investigates a possible source of inflammatory mediators involved in the pathogenesis of bladder inflammation characteristics of interstitial cystitis disease. Our tested hypothesis is that in response to injury, tissues of the urinary bladder participate in the initiation of bladder inflammation by releasing inflammatory mediators such as neutrophil chemotactic factors. Bladders of anesthetized rabbits (n = 7) were instilled with an acidic solution (pH 4.5) for 15 minutes, then washed with saline and instilled with sterile phosphate buffered saline (PBS) (pH 7.2) for an additional 45 minutes prior to sacrificing the rabbits. Control rabbits (n = 7) were instilled with sterile PBS (pH 7.2) for 15 minutes, then 45 minutes. The levels of neutrophil chemotactic factors were measured using modified Boyden chambers and rabbit peritoneal neutrophils as indicator cells. Results indicated the release of high levels of neutrophil chemotactic factors (via a checkerboard analysis) from acid-treated bladders after 15 minutes (70 +/- 4% of standard) and 45 minutes (80 +/- 7%). Electron microscopy analysis of these acid-treated bladders revealed the infiltration of a large number of neutrophils, which correlates with the recovery of neutrophil chemotactic factors. Control rabbits, on the other hand, showed low levels of chemotactic activity (less than 10 percent) and exhibited normal bladder morphology with absence of neutrophils. The glycosaminoglycan (GAG) layer was intact in both acid-treated and control bladders. High levels of neutrophil chemotactic factors were also detected in urine samples from eleven patients with interstitial cystitis (113 +/- 25%) (not due to interleukin-1 or leukotriene B4) which were not detected in urine samples from healthy volunteers (n = 9) or from thirteen control patients with bladder diseases other than interstitial cystitis. These preliminary studies indicate the capability of injured bladder tissues to release neutrophil chemotactic factors which contribute to the initiation of bladder inflammation. The presence of neutrophil chemotactic factors in urine samples of interstitial cystitis patients suggests a possible role of these mediators in the pathogenesis of the disease.     

Abnormal sensitivity to intravesical potassium in interstitial cystitis and radiation cystitis

The urgency-frequency syndrome (UFS) (non-bacterial cystitis, interstitial cystitis) may well represent a heterogenous group with several etiologies. This study was based on the hypothesis that one subset of UFS patients has a leaky (to solutes) epithelium and cations such as potassium could thereby diffuse subepithelially and provoke symptoms. It was also hypothesized that normal impermeable transitional epithelium would not allow cations to diffuse across the cells during the K + provocation test and no symptoms would be experienced. If the epithelium was permeable (“leaky”), diffusion would occur and provoke symptoms. Water or 0.4 M KCl was placed intravesically into normal volunteers and interstitial cystitis (IC) patients. Water did not provoke symptoms in either group but KCl provoked 45% of normals and 70% of IC patients. Differences were significant (P < 0.0001). This test provides a valuable diagnostic tool for UFS and a valuable research tool to separate epithelial permeability problems from other subsets of patients. A third group, consisting of 11 IC patients in remission on heparinoid therapy, was also tested and only 18% were provoked by KCl. Four patients with radiation cystitis were also examined and all four (100%) were provoked by the potassium. © 1994 Wiley-Liss, Inc.     

A diagnostic in vitro urine assay for interstitial cystitis

Objectives. A low molecular weight urine factor that inhibits the proliferation of normal bladder epithelial cells in vitro was previously shown to be present significantly more often in the urine of patients with interstitial cystitis (IC) than in the urine of asymptomatic age-, race-, and sex-matched control subjects. We sought to determine the specificity of this finding for IC by determining whether the urine of patients with other urogenital inflammatory disorders also contains a factor that inhibits bladder epithelial cell proliferation.Methods. Urine was collected from women with IC, acute bacterial cystitis, or vulvovaginitis, as well as from asymptomatic control women. The proliferation of primary normal adult bladder epithelial cells was determined by measuring ³H-thymidine incorporation in vitro.Results. Osmolality- and pH-corrected urine specimens from 50 (86%) of 58 women with IC significantly inhibited human bladder epithelial cell proliferation compared with 3 (8%) of 36 asymptomatic control women, 7 (12%) of 58 women with bacterial cystitis, and 0 (0%) of 12 women with vulvovaginitis (P < 0.001 for the comparison of mean percent change in ³H-thymidine incorporation with IC urine versus urine from each of the control groups). Optimal sensitivity and specificity values of 91.4% and 90.6%, respectively, were achievable at a cutoff of 25% inhibition of ³H-thymidine incorporation, using all three control groups.Conclusions. The measurement of urine antiproliferative activity may be a useful noninvasive means for diagnosing IC in women.     

A new direct test of bladder permeability

PURPOSE: A proposed cause of interstitial cystitis is increased bladder permeability but to our knowledge this theory has not been proved by direct testing. We developed a safe, relatively painless, direct test of bladder permeability. MATERIALS AND METHODS: The original permeability test involved placing 4% lactulose and 1% rhamnose intravesically, then drawing blood to assay for these sugars. Initial feasibility studies were performed in rabbits with bladder epithelium that was intact or disrupted by a 50% acetone rinse. In humans the initial goal was to distinguish intact bladders from those known to have increased permeability. Since distention is known to increase permeability temporarily, we studied patients with interstitial cystitis immediately after distention. RESULTS: Neither sugar was absorbed from intact rabbit bladders, while each was absorbed from acetone rinsed bladders at 10, 20 and 30 minutes. We used 100 ml. of solution in the initial 8 humans, including 6 with interstitial cystitis and 2 controls. At 30 minutes each sugar was absorbed from interstitial cystitis bladders but neither was absorbed from intact bladders. The test solution was then changed to 5% rhamnose. Mean rhamnose absorption plus or minus standard deviation was much greater in the 6 patients with interstitial cystitis than in 8 controls (26.3 + or - 26.1 versus 0.78 + or - 0.87 nmol. /ml. serum, p = 0.008). With 1 exception interstitial cystitis serum levels were at least 4-fold higher than the highest control level. CONCLUSIONS: This new permeability test clearly distinguishes intact versus distended bladders. It may be performed to test whether bladder permeability is increased in interstitial cystitis.     

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). METHODS: Tamm-Horsfall protein was extracted from the urine of interstitial cystitis (IC) patients (N=28) and normal volunteers (N=5). Urothelial target cells (T24) were radiolabeled with 51Cr and then exposed to PS (0-1.0 mg/mL) for either 1.5 or 20 h. The resulting cytotoxicity data (dose-response curves) were then compared with the data obtained when PS was preincubated with 0-0.5 mg/mL of THP (IC vs normal), the semisynthetic polysaccharide, pentosan polysulfate (Elmiron), or human serum albumin. RESULTS: Toxicity of PS was significantly reduced by incubation with THP (or Elmiron) prior to evaluation by the chromium release assay, but not reduced by incubating with another protein, albumin. Tamm-Horsfall protein from IC patients' urine was less protective than an equal quantity of THP from normal urine. CONCLUSIONS: These experiments suggest that THP has an important role in bladder mucosal defense mechanisms, protecting the bladder surface from injury. Inability of THP to prevent cytotoxic damage by urinary polyamine or other urinary toxins (cationic species) may be relevant in the etiology of interstitial cystitis, as putative urinary toxic components have been described in the urine of some patients.     

Interstitial cystitis is associated with intraurothelial Tamm-Horsfall protein

A defective barrier between the urine and urothelium has been suggested as an etiology for interstitial cystitis. With immunohistochemical techniques we assayed the bladder biopsies of 14 interstitial cystitis patients and 10 normal controls for intraurothelial Tamm-Horsfall protein to assess indirectly the in vivo permeability of the urothelium. Eight pathological controls, including bladder biopsies from 3 patients with inflammation owing to infection or catheterization and biopsies of 5 transitional cell carcinomas of the bladder, also were assayed. Superficial intraurothelial Tamm-Horsfall protein was identified in the biopsies from 10 of 14 interstitial cystitis patients (71 per cent) but only 1 of 10 controls (10 per cent) (p less than 0.01). Tamm-Horsfall protein was not identified in biopsies from the pathological controls. In 6 of 7 cases when more than 1 biopsy was available for analysis the findings were identical in each specimen. There was a direct correlation between the density of detrusor mast cells and the demonstration of intraurothelial Tamm-Horsfall protein. Seven of the 9 evaluable interstitial cystitis patients with intraurothelial Tamm-Horsfall protein but only 1 of 4 without intraurothelial Tamm-Horsfall protein experienced a favorable response to intravesicle oxychlorosene sodium (p greater than 0.05). These data suggest that abnormal permeability of the urothelium is associated with and a possible cause of interstitial cystitis and that the demonstration of intraurothelial Tamm-Horsfall protein in bladder biopsy specimens may prove to be useful as a diagnostic test for interstitial cystitis.     

THE URINARY GLYCOPROTEIN GP51 AS A CLINICAL MARKER FOR INTERSTITIAL CYSTITIS

PURPOSE: GP51 is a urinary glycoprotein with a molecular weight of 51 kDa. This glycoprotein is produced and secreted by the transitional epithelium of the genitourinary tract, and has been isolated from human urine. Studies have demonstrated that GP51 levels are decreased in bladder biopsies of patients with interstitial cystitis. We evaluated urinary GP51 in a noninvasive manner as a clinical marker of interstitial cystitis. MATERIALS AND METHODS: Urinary GP51 levels were measured using antigen inhibition enzyme-linked immunosorbent assay. In blinded fashion we analyzed for quantitative differences 24-hour urine samples of 36 patients with interstitial cystitis and 23 normal controls who were age matched within 5 years (mean age 47.3). We also evaluated GP51 in random urine specimens of 17 normal controls, 14 patients with interstitial cystitis and 11 subjects who had undergone cystectomy to determine whether urinary GP51 is mainly produced by the bladder, which is the site of interstitial cystitis. To ascertain the specificity of urinary GP51 to interstitial cystitis urine samples of 34 patients with other urological diseases were measured and compared with findings in the samples of 15 with interstitial cystitis. RESULTS: Low GP51 levels appeared to be unique to the interstitial cystitis state compared to normal (p = 0.008). GP51 in patients with interstitial cystitis and in those who underwent cystectomy was lower (p < 0.001) than in normal controls. These findings suggest that the major source of urinary GP51 is the bladder. Also, we observed lower GP51 levels in interstitial cystitis than in other urinary tract diseases (p < 0.0001). CONCLUSIONS: Our study substantiates the possibility of using GP51 as a clinical marker for diagnosing interstitial cystitis by a noninvasive urinary assay.     

DETECTION OF EUBACTERIA IN INTERSTITIAL CYSTITIS BY 16S rDNA AMPLIFICATION

Objective

To determine what role non-culturable microorganisms play in the etiology of interstitial cystitis (IC).

Materials and Methods

Thirty patients fulfilling NIH criteria for the diagnosis of interstitial cystitis and sixteen control patients with culture negative urine gave written informed consent and underwent bladder biopsy. Polymerase chain reaction (PCR) using two sets of universal primers for bacterial 16S rDNA was performed on urine from the cystoscope and on a cold cup bladder biopsy specimen. Of the PCR positive bladder biopsies, three patients with interstitial cystitis and three controls were randomly selected and cloned. Ten clones from each were sequenced and putative taxonomic assignments made.

Results

12/26 (46%) IC and 5/12 (42%) control urine specimens and 16/30 (53%) and 9/15 (60%) bladder biopsies were PCR positive, respectively. The bacterial populations in the two patient groups tested appeared to be different based upon analysis of the 16S rRNA sequences.

Conclusions

Both IC and control patients had non-culturable bacteria in their bladders. A random sampling of the two populations revealed that the bacterial populations are different, suggesting a possible link between one or more bacterial species and IC.     

Functional results after ileocystoplasty

The functional results after ileocystoplasty were studied in seven patients with interstitial cystitis, irradiated bladder and neurogenic bladder dysfunction. None of the patients had had symptomatic improvement by medical or surgical means. All patients were suffering from urinary frequency and five patients had severe urge incontinence or suprapubic pains. Postoperatively the patients were followed from 8 to 66 months and evaluated by urodynamic examinations and interviews. Urinary frequency was improved in all patients but one with interstitial cystitis who had persisting suprapubic pains. None had residual urine volume greater than 30 ml postoperatively. It is concluded that bladder augmentation by ileocystoplaty is an excellent method of treatment for patients with contracted bladder secondary to interstitial cystitis, irradiated bladder, and detrusor hyperreflexia and sphincter dyssynergia.     

Low-molecular-weight inhibitor of in vitro fibroblast colony formation from human urine

Summary The role of urinary toxins in interstitial cystitis (IC) has been suggested. This report describes the partial purification of a substance from human urine that inhibited in vitro colony formation by mouse fibroblasts. Urine samples from 15 women with IC and 17 healthy women serving as volunteers were fractioned by ultrafiltration and chromatography methods and tested by the inhibition of Swiss 3T3 fibroblast colony formation. The fibroblasts were cultured at low density with varying concentrations of whole or fractioned urine. Colonies were counted at 10 days. Colony formation was reduced by incubation with whole urine, ultrafiltrate, and nonadsorbed C18 fractions. Inhibition of colony formation by urine from healthy volunteers or women with IC was not significantly different. In vitro colony formation by Swiss 3T3 cells was inhibited by a component of human urine. The toxicity of urine from IC patients was not different from that of urine from healthy controls.     

Clinical experience with multiagent intravesical therapy in interstitial cystitis patients unresponsive to single-agent therapy

Summary A total of 25 patients with the diagnosis of interstitial cystitis (IC) were involved in this study. All patients had been previously diagnosed with interstitial cystitis and had received treatment with single intravesical agents. Patients were divided into two groups according to their bladder capacity. The bladder capacity was >350 ml in group I patients and <350 ml in group II patients. For our study, dimethylsulfoxide (DMSO), methylprednisolone, and heparin sulfate were given every week for a total of 6 weeks. When symptoms recurred, supportive oral pharmacotherapy consisting of anticholinergics and/or tricyclic antidepressants was given. Under anesthesia, patients in group I showed a 99% increase in their bladder capacity; whereas those in group II showed an increase of only 19%. Cystoscopically, Hunner's ulcers were present in 60% of the group II patients but were seen in only 5% of the group I patients. Histopathological examination showed that the inflammatory changes were more frequent and severe in group II than in group I. Mast-cell hyperplasia was present in 100% of the patients in group II, versus only 61% of those in group I. A total of 23 patients (92%) achieved an initial remission averaging 8.1 months. In all, 9 patients (35%) had 1 or more relapses, and all achieved a subsequent remission averaging 8 months. By this combined multiagent approach, the majority of patients with IC obtained relief from their incapacitating symptoms and were socially rehabilitated.     

Decreased nanobacteria levels and symptoms of nanobacteria-associated interstitial cystitis/painful bladder syndrome after tetracycline treatment

Introduction and hypothesis  

This study was designed to detect whether nanobacteria (NB) reside in urine and bladder tissue samples of patients with interstitial cystitis/painful bladder syndrome (IC/PBS) and whether antibiotic therapy targeting these organisms is effective in reducing NB levels and IC/PBS symptoms.     

Angiogenic factors,bladder neuroplasticity and interstitial cystitis—new pathobiological insights

Vascular endothelial growth factor (VEGF) is essential for normal embryonic development, and maintenance of adult vascular function. Originally described as a vascular permeability factor, VEGF alters tight cell junctions and contributes to maintenance of bladder permeability. VEGF and its receptors are not only expressed in bladder blood vessels but also in apical cells and intramural ganglia. VEGF receptors are fundamentally altered by inflammation and bladder diseases such as interstitial cystitis (IC). Experimental results indicate that VEGF exerts direct effects on bladder nerve density and function. Regardless of the etiology or initiating cause for IC, it is hypothesized that the urinary bladder responds to injury by increasing the production of VEGF that acts initially as a survival mechanism. However, VEGF also has the capacity to increase vascular permeability leading to glomerulations, edema, and inflammation. Moreover, due to elevated numbers of VEGF receptors in the urothelium, the increased levels of VEGF further increase bladder permeability and establish a vicioCus cycle of disease pathophysiology.     

Increased bladder permeability in interstitial cystitis/painful bladder syndrome

The definition of interstitial cystitis (IC) has evolved over the years from being a well-defined entity characterized by diagnostic lesion (Hunner’s ulcer) in the urothelium to a clinical diagnosis by exclusion [painful bladder syndrome (PBS)]. Although the etiology is unknown, a central theme has been an association with increased permeability of the bladder. This article reviews the evidence for increased permeability being important to the symptoms of interstitial cystitis/painful bladder syndrome (IC/PBS) and in treating the disorder. Recent work showing cross-communication among visceral organs is also reviewed to provide a basis for understanding IC/PBS as a systemic disorder of a complex, interconnected system consisting of the bladder, bowel and other organs, nerves, cytokine-responding cells and the nervous system.     

Does interstitial cystitis urine include possible factors effecting the nociceptive system of the spinal cord?

INTRODUCTION: We investigated the effect of interstitial cystitis (IC) urine on bladder layers and nociceptive centers in the spinal cord with determination of nerve growth factor (NGF), neuronal nitric oxide synthase (nNOS) and c-fos expressions. MATERIAL AND METHODS: Female rats were instilled into the bladder IC urine (Group-IC), normal urine (Group-NU) and saline (Group-S). NGF, nNOS and c-fos activity were determined in the L6-S1 medulla spinalis with identification of mast cell and NGF activity on bladder layers. RESULTS: There was more NGF expression cell density in the bladder wall that was determined immunohistochemically in control and IC urine instillation groups than Group-S. While there was no difference in nNOS, NGF and c-fos activity between spinal cord regions except the lateral dorsal horn of the L6 section, localization of activities was different in Group-IC. CONCLUSIONS: The characteristics of the bladder wall and its nociceptive afferents after human urine instillation of some toxic compounds might be causative factors for IC. However, it is barely hard to conclude that different toxic compounds should be causative factors in IC urine in the pathogenesis of IC.     

Stimulated release of urine histamine in interstitial cystitis.

The diagnosis of interstitial cystitis is primarily made based on clinical and cystoscopic findings with exclusion of other bladder diseases. Despite all of the efforts at definitive identification, interstitial cystitis lacks universal objective findings. Mast cell activation with associated histamine release has been postulated as an etiological factor leading to the symptom complex associated with interstitial cystitis. To investigate this hypothesis, a 3-step controlled prospective study was conducted. In step 1 reliability of urine histamine assay was critically examined, and the assay was established to be simple, reliable and valid. In step 2 random spot urine histamine levels (basal state) were measured in 25 noninterstitial cystitis and 15 interstitial cystitis patients (22.1 +/- 0.95 ng./ml. versus 19.2 +/- 1.19 ng./ml.). There was no significant difference in the random urine histamine levels between the 2 groups (p greater than 0.05). In step 3 urine histamine levels were measured before and after hydrodistention (acute stimulation) in 7 noninterstitial cystitis controls and 6 newly diagnosed interstitial cystitis patients under general anesthesia. The urine histamine-to-creatinine ratio was used to correct for the dilutional effect of normal saline used during hydrodistention. The urine histamine-to-creatinine ratios of the control group showed no significant difference before and after hydrodistention. However, the difference in the urine histamine-to-creatinine ratios of the interstitial cystitis group compared to the controls before and after hydrodistention was highly significant (p less than 0.001). Although measurement of random spot urine histamine alone (basal state) was not found useful to make the diagnosis of interstitial cystitis, measurement of urine histamine before and immediately after hydrodistention (acute stimulation) may become an important objective parameter to assist in the diagnosis of interstitial cystitis.     

Urinary levels of substance P and its metabolites are not increased in interstitial cystitis

OBJECTIVES: To determine whether interstitial cystitis is associated with the increased release of substance P from the bladder wall into urine, by measuring urinary excretion rates of substance P and its metabolites in women with interstitial cystitis and in a control group of women with stress incontinence and normal bladder function. PATIENTS AND METHODS: Catheter urine was collected from 13 patients and 10 controls during a water diuresis ( approximately 10 mL/min) before and after instilling the bladder with 100 mL of water. The contribution of the bladder wall to urinary substance P peptides was assessed by measuring the change in substance P peptide levels after 2 min of bladder stasis before and after instillation. RESULTS: Absolute substance P excretion rates were similar in patients with interstitial cystitis and controls; 2 min of bladder stasis reduced the substance P excretion rate (P = 0.03) and increased the excretion rate of substance P metabolites (P = 0.01). CONCLUSIONS: The release of substance P from the bladder wall was not increased in patients with interstitial cystitis.     

ANTIPROLIFERATIVE ACTIVITY IS PRESENT IN BLADDER BUT NOT RENAL PELVIC URINE FROM INTERSTITIAL CYSTITIS PATIENTS

PURPOSE: To determine whether an antiproliferative urine factor that we previously discovered to be specific for urine from interstitial cystitis (IC) patients originated in the lower urinary tract or a more proximal site. MATERIALS AND METHODS: Sequential catheterized urine specimens were collected under sterile conditions from the bladder and renal pelvis of 20 IC patients and one control patient (with stress incontinence). Antiproliferative activity was determined by 3H-thymidine incorporation of primary normal adult bladder epithelial cells cultured with pH- and osmolality-corrected bladder or ureteral urine specimens; significant inhibition was defined as a change in 3H-thymidine incorporation greater than 2 standard deviations from the mean of control cells. RESULTS: Bladder urine specimens from 19 of 20 IC patients significantly inhibited 3H-thymidine incorporation as compared to cell medium alone (mean change for bladder specimens = -68.7+/-7.5%), while a renal pelvic specimen from only 1 of 20 IC patients inhibited proliferation significantly (mean change for renal pelvic specimens = 3.2+/-3.4%) (p<.001 by Fisher's exact test). The one inhibitory IC renal pelvic specimen inhibited by 31% while a bladder specimen obtained during the same procedure inhibited by 94%. In comparison, neither bladder nor renal pelvic urine from the control patient had inhibitory activity. CONCLUSIONS: The antiproliferative factor previously found in the urine of IC patients appears to be made and/or activated in the distal ureter or urinary bladder.