Estrogen deficiency Induced Bladder Blood Flow Changes When Bladder Capacity was Low Volume

Imai Y1, Yamaguchi O2, Nomiya M3, Takeda M1

Research Type

Basic Science / Translational

Abstract Category

Female Lower Urinary Tract Symptoms (LUTS) / Voiding Dysfunction

Abstract 490
Basic Science: Stress Urinary Incontinence and Benign Prostatic Hyperplasia
Scientific Podium Short Oral Session 27
Friday 31st August 2018
09:37 - 09:45
Hall D
Female Overactive Bladder Basic Science
1. Department of Urology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 2. College of Engineering, Nihon University, 3. National Center for Geriatrics and Gerontology

Yuki Imai



Hypothesis / aims of study
Menopause and subsequent estrogen deficiency have been implicated in the etiology of overactive bladder (OAB) in elderly females. Recently, attention has focused on ischemia of the bladder as a common pathophysiological mechanism for lower urinary tract symptoms (LUTS), including OAB [1]. In the present study, we investigated the effects of ovariectomy (OVX) and estrogen replacement on bladder blood flow (BBF) with an increase in bladder volume.
Study design, materials and methods
Virgin Sprague-Dawley rats (24-week old) randomly received a sham operation (SHAM), ovariectomy (OVX), and ovariectomy plus estrogen replacement (OVX+E). In the OVX+E group, the rats were immediately treated with 1mg/Kg weekly injection with β-estradiol for 4weeks.
Four weeks after OVX, rats from the three groups anesthetized with urethane, and the anterior bladder was exposed for the measurement of BBF. Rats were underwent catheter implantation in the bladder . At room temperature, saline was infused at rate of 4ml per hour up to 0.3ml. A laser speckle blood flow imager (OMEGAWAVE, INC. Tokyo, Japan) was used to measure BBF(Fig.1).
When bladder volume was 0ml or 0.1ml, a significant decrease in BBF was observed in OVX rats. BBF in the OVX group was significantly lower than in the SHAM group. This decrease in BBF was significantly suppressed by estradiol treatment . When bladder volume was 0.2ml or 0.3ml, there was no significant difference in BBF(Fig.2).
Interpretation of results
The present study showed that OVX reduced BBF (ischemia of the bladder)  when bladder capacity was low volume.  Estrogen replacement was shown to restore BBF. Since bladder ischemia is known to cause functional and structural alterations of the bladder and estrogen deficiency induce bladder hyperactivity in our previous data, decreased BBF with low bladder volume may play a potential role in the development of bladder hyperactivity in rats with estrogen deficiency.
Concluding message
This study implicates that bladder ischemia caused by estrogen deficiency was induced  when bladder capacity was low volume.
Figure 1
Figure 2
Funding No funding and grant Clinical Trial No Subjects Animal Species Rat Ethics Committee Principles in the Care and Use of Animals in the Field of the Physiologic Society of Japan, and the policies of the Institutional Animal Care and Use Committee of the University of Yamanashi (Chuo, Yamanashi, Japan)