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Controlled release of insulin‐like growth factor 1 enhances urethral sphincter function and histological structure in the treatment of female stress urinary incontinence in a rat model
Author(s) -
Yan Hao,
Zhong Liren,
Jiang Yaodong,
Yang Jian,
Deng Junhong,
Wei Shicheng,
Opara Emmanuel,
Atala Anthony,
Mao Xiangming,
Damaser Margot S.,
Zhang Yuanyuan
Publication year - 2018
Publication title -
bju international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.773
H-Index - 148
eISSN - 1464-410X
pISSN - 1464-4096
DOI - 10.1111/bju.13985
Subject(s) - saline , urology , medicine , urethral sphincter , urinary incontinence , urethra , distension , sphincter , growth factor , insulin like growth factor , endocrinology , surgery , receptor
Objectives To determine the effects of controlled release of insulin‐like growth factor 1 ( IGF ‐1) from alginate‐poly‐L‐ornithine‐gelatine (A‐ PLO ‐G) microbeads on external urethral sphincter ( EUS ) tissue regeneration in a rat model of stress urinary incontinence ( SUI ), as SUI diminishes the quality of life of millions, particularly women who have delivered vaginally, which can injure the urethral sphincter. Despite several well‐established treatments for SUI , growth factor therapy might provide an alternative to promote urethral sphincter repair. Materials and Methods In all, 44 female Sprague‐Dawley rats were randomised into four groups: vaginal distension ( VD ) followed by periurethral injection of IGF ‐1‐A‐ PLO ‐G microbeads ( VD + IGF ‐1 microbeads; 1 × 10 4 microbeads/1 mL normal saline); VD + empty microbeads; VD + saline; or sham‐ VD + saline (sham). Results Urethral function (leak‐point pressure, LPP ) was significantly lesser 1 week after VD + saline [mean ( sem ) 23.9 (1.3) cmH 2 O] or VD + empty microbeads [mean ( sem ) 21.7 (0.8) cmH 2 O) compared to the sham group [mean ( sem ) 44.4 (3.4) cmH 2 O; P < 0.05), indicating that the microbeads themselves do not create a bulking or obstructive effect in the urethra. The LPP was significantly higher 1 week after VD + IGF ‐1 microbeads [mean ( sem ) 28.4 (1.2) cmH 2 O] compared to VD + empty microbeads ( P < 0.05), and was not significantly different from the LPP in sham rats, demonstrating an initiation of a reparative effect even at 1 week after VD . Histological analysis showed well‐organised skeletal muscle fibres and vascular development in the EUS at 1 week after VD + IGF ‐1 microbeads, compared to substantial muscle fibre attenuation and disorganisation, and less vascular formation at 1 week after VD + saline or VD + empty microbeads. Conclusion Periurethral administration of IGF ‐1‐A‐ PLO ‐G microbeads facilitates recovery from SUI by promoting skeletal myogenesis and revascularisation. This therapy is promising, but detailed and longer term studies in animal models and humans are needed.