Expression and significance of lysyl oxidase-like 1 and fibulin-5 in the cardinal ligament tissue of patients with pelvic floor dysfunction

Abstract

Pelvic organ prolapse (POP) is a disabling disorder in women characterized by a loss of pelvic floor support, leading to the herniation of the uterus into or through the vagina. POP is a complex problem that likely involves multiple mechanisms with limited therapies available, and is associated with defects in connective tissue including elastic fibers. This study was designed to investigate the expression of fibulin-5 and lysyl oxidase-like 1 (LOXL1) in the cardinal ligament in samples taken from the POP group compared to the non-POP group. Specimens were obtained during abdominal hysterectomy from the cardinal ligament of 53 women with POP and 25 age- and parity- matched women with non-POP among post-menopausal women with benign gynecologic pathology. Protein expression was evaluated using the immunohistochemical staining method. For statistical analyses, chi-square test and Spearman's correlation were used with the statistical package SPSS13.0 system. Our results showed that both fibulin-5 and LOXL1 expressions were decreased in the cardinal ligament in the POP group compared to the non-POP group (P < 0.05). The expression of fibulin-5 and LOXL1 were correlated closely with the stage of POP, accompanied by stress urinary incontinence and frequency of vaginal delivery (P < 0.05), but had no relationship with post-menopausal state (P > 0.05). The expression of fibulin-5 was positively associated with LOXL1 in POP (P < 0.05). We conclude that changes in fibulin-5 and LOXL1 expression may play a role in the development of POP.

Keywords: fibulin-5; lysyl oxidase-like 1; pelvic floor dysfunction; pelvic organ prolapse; stress urinary incontinence.

Fig. 1. Expressions of lysyl oxidase-like 1 (A) and fibulin-5 (B) by immunohistochemistry (magnification: ×400; scale bar: 50 µm).

Positive expression was indicated by brown-yellow granules in the cardinal ligament tissues of patients with pelvic organ prolapse.