Elsevier

Urology

Volume 61, Issue 6, June 2003, Pages 1278-1284
Urology

Basic science
Decreased in vitro proliferation of bladder epithelial cells from patients with interstitial cystitis

https://doi.org/10.1016/S0090-4295(03)00005-0Get rights and content

Abstract

Objectives

To determine whether explanted bladder epithelial cells from patients with interstitial cystitis (IC) display intrinsically decreased rates of proliferation in vitro, and to compare the growth rates of untreated IC and normal bladder cells with the rates of normal cells treated with a purified antiproliferative factor (APF) at levels found in urine from patients with IC.

Methods

Epithelial cell explants were prepared from the bladder biopsies of 4 patients with IC and 2 asymptomatic controls. Cell proliferation was determined by serial counting of trypan blue-negative cells. APF and mock APF were purified chromatographically, and activity was determined by 3H-thymidine incorporation into primary normal bladder epithelial cells. Heparin-binding epidermal growth factor-like growth factor and epidermal growth factor were measured by enzyme-linked immunosorbent assay.

Results

Bladder epithelial cells from patients with IC proliferated significantly less than did control cells by day 2 after serum starvation (P = 0.02). Similar inhibition of the proliferation rate was seen in control cells treated with APF; APF-induced changes in heparin-binding epidermal growth factor-like growth factor, but not epidermal growth factor, production by cells were associated with changes in growth rates.

Conclusions

The proliferation rate of explanted bladder epithelial cells from patients with IC in serum-free medium was significantly less than that of control cells, indicating an intrinsic abnormality in IC cell proliferation. This abnormality may be caused by APF, which induces reversible inhibition of heparin-binding epidermal growth factor-like growth factor production and normal bladder epithelial cell proliferation.

Section snippets

Patients

Patients who had previously undergone cystoscopy and fulfilled the National Institute of Diabetes, Digestive and Kidney Diseases diagnostic criteria for IC,13 and 1 asymptomatic control undergoing pelvic surgery for an unrelated disorder, were enrolled for these studies. All participants were at least 18 years old and were enrolled in accordance with the guidelines of the Institutional Review Board of the University of Maryland School of Medicine.

Cell culture

Cystoscopy was performed under general

Decreased proliferation of bladder epithelial cell explants from patients with IC

Bladder epithelial cells from patients with IC and controls were plated at approximately 30% confluence (day −1), serum-starved (day 0), and counted in duplicate wells on successive days in culture. On the days indicated, the cells were trypsinized, stained with trypan blue, and both live and dead cells enumerated.

Explanted epithelial cells from patients with IC had much lower rates of proliferation than did normal cells (Fig. 1A). Normal cells had an initial doubling time of 1.2 days,

Comment

The data presented indicate three important findings regarding a possible pathogenesis for IC. First, bladder epithelial cells from patients with IC have intrinsically decreased rates of proliferation in vitro in serum-free medium compared with cells from asymptomatic controls. Although the relationship of these findings to other previously reported intrinsic abnormalities in bladder epithelial cells from patients with IC14 is currently unknown, our findings provide additional evidence that

Conclusions

Bladder epithelial cells explanted from biopsies from patients with IC have an intrinsically abnormal decreased rate of proliferation in vitro in serum-free medium, providing additional evidence that the bladder epithelium is intrinsically abnormal in IC. In addition, a reversible inhibition of cell proliferation can be induced in normal cells by the same levels of APF found in urine from patients with IC and is associated temporally with changes in HB-EGF (but not EGF) production.

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This work was supported by funding from the National Institutes of Health (NIDDK R01 DK52596 and NIDDK R01 DK59441) and Veterans Affairs Merit Review funding.

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