Vaginal Expression of LOXL1 in Premenopausal and Postmenopausal Women With Pelvic Organ Prolapse

Objectives This study aimed to compare cellular expression of lysyl oxidase-like 1 (LOXL1), a key enzyme in elastin metabolism, of premenopausal women with pelvic organ prolapse (POP) compared with premenopausal controls without POP and postmenopausal women with POP. In addition, we examined whether variation of LOXL1 expression was dependent on biopsy site. Methods A standardized protocol was utilized to obtain vaginal biopsies from 30 women (10 premenopausal POP, 10 postmenopausal POP, and 10 premenopausal non-POP). Expression levels of messenger RNA (mRNA) and protein of LOXL1 were determined using real-time quantitative polymerase chain reactions and enzyme-linked immunosorbant assays. Analysis was performed to determine if there were differences between group or biopsy site. Results Significant differences in LOXL1 mRNA expression were found between patient groups (P = 0.0033). LOXL1 mRNA expression (relative to 18S) was upregulated in the postmenopausal POP group (54.5 ± 14.7) compared with the premenopausal POP group (5.2 ± 14.7, P = 0.0034) and the premenopausal non-POP group (23 ± 18, P = 0.0359). No significant differences in LOXL1 protein expression (nanogram/milliliter per microgram total protein) were seen between groups (premenopausal POP, 3.2 × 10 ± 6.3 × 10; postmenopausal POP, 4.3 × 10 ± 6.3 × 10; premenopausal non-POP, 5.0 × 10 ± 7.7 × 10; P = 0.15). No differences in mRNA expression were seen between sites (P = 0.74), but significant variation was noted in protein expression (P = 0.001). Conclusions Premenopausal and postmenopausal women with POP exhibit differential expression of LOXL1 suggesting different pathways in the pathogenesis of POP. The role of biopsy location on LOXL1 expression requires further investigation.