Sensitivity and specificity of antiproliferative factor, heparin-binding epidermal growth factor-like growth factor, and epidermal growth factor as urine markers for interstitial cystitis.

We previously determined that the urine of interstitial cystitis (IC) patients specifically contains a factor (antiproliferative factor [APF]) that inhibits primary bladder epithelial cell proliferation, and that it has significantly decreased levels of heparin-binding epidermal growth factor-like growth factor (HB-EGF) and increased levels of epidermal growth factor (EGF) compared with urine from asymptomatic controls and patients with bacterial cystitis. We sought to confirm the specificity of these findings for IC using a larger patient population, including control patients with a variety of urogenital disorders. Clean catch urine specimens were collected from 219 symptomatic IC patients, 113 asymptomatic controls without bladder disease, and 211 patients with various urogenital diseases including acute bacterial cystitis, vulvovaginitis, chronic nonbacterial prostatitis, overactive bladder, hematuria, stress incontinence, neurogenic bladder, benign prostatic hyperplasia, bladder or pelvic pain without voiding symptoms, bladder cancer, prostate cancer, or miscellaneous diagnoses including anatomic disorders. APF activity was determined by (3)H-thymidine incorporation into primary normal adult human bladder epithelial cells. HB-EGF and EGF levels were determined by enzyme-linked immunosorbent assay. APF activity was present significantly more often in IC than control urine specimens (P <0.005 for IC vs any control group; sensitivity = 94%, specificity = 95%, P <10(-82) for IC vs all controls). HB-EGF levels were also significantly lower and EGF levels significantly higher in IC urine than in specimens from controls (P <10(-84) and P <10(-36), respectively). These findings confirm the utility of APF, HB-EGF, and EGF as markers for IC. Understanding the reasons for altered levels of these markers may lead to understanding the pathogenesis of this disorder.

Bladder stretch alters urinary heparin-binding epidermal growth factor and antiproliferative factor in patients with interstitial cystitis.

PURPOSE: The etiology of interstitial cystitis is unknown. Urine from patients with interstitial cystitis has been shown to inhibit urothelial proliferation through a putative antiproliferative factor and to contain decreased levels of heparin-binding epidermal growth factor-like growth factor (HB-EGF) compared to controls. Stretch of detrusor smooth muscle cells is known to stimulate HB-EGF production. Because bladder hydrodistention sometimes alleviates the symptoms of interstitial cystitis, we determined whether the stretch stimulus of hydrodistention alters antiproliferative factor activity and/or HB-EGF in interstitial cystitis urine specimens. MATERIALS AND METHODS: Urine was collected immediately before, and 2 to 4 hours and 2 weeks after hydrodistention from 15 patients with symptoms and cystoscopic findings compatible with interstitial cystitis and 13 controls. Hydrodistention was performed with the subject under general or regional anesthesia and bladders were distended to 80 cm. water 3 times. Urinary HB-EGF was measured by enzyme-linked immunosorbent assay and urinary antiproliferative factor activity was determined by measuring 3H-thymidine uptake by normal human bladder urothelial cells. RESULTS: Hydrodistention significantly increased urinary HB-EGF in patients with interstitial cystitis toward normal control values (before distention p = 0.003, 2 weeks after distention p = 0.67). Urine antiproliferative factor activity decreased significantly after hydrodistention in patients with interstitial cystitis. However, antiproliferative factor activity in interstitial cystitis and control specimens was still statistically different 2 weeks after distention (before distention p = 0.0000004, 2 weeks after distention p = 0.04). CONCLUSIONS: Bladder stretch increased HB-EGF and conversely reduced antiproliferative factor activity in urine from patients with interstitial cystitis but not controls up to 2 weeks after distention. These results provide additional evidence for the possible role of antiproliferative factor and decreased HB-EGF in the pathophysiology of interstitial cystitis. To our knowledge this is also the first human study to show that in vivo bladder stretch can alter urinary factors that regulate cell growth.