Elastin homeostasis is altered with pelvic organ prolapse in cultures of vaginal cells from a lysyl oxidase-like 1 knockout mouse model

Pelvic organ prolapse (POP) decreases quality of life for many women, but its pathophysiology is poorly understood. We have previously shown that Lysyl oxidase‐like 1 knockout (Loxl1 KO) mice reliably prolapse with age and increased parity, similar to women. Both this model and clinical studies also indicate that altered elastin metabolism in pelvic floor tissues plays a role in POP manifestation, although it is unknown if this is a cause or effect. Using Loxl1 KO mice, we investigated the effects of genetic absence of Loxl1, vaginal parity, and presence of POP on the expression of genes and proteins key to the production and regulation of elastic matrix. Cultured cells isolated from vaginal explants of mice were assayed with Fastin for elastic matrix, as well as RT‐PCR and Western blot for expression of genes and proteins important for elastin homeostasis. Elastin synthesis significantly decreased with absence of LOXL1 and increased with parity (p < .001), but not with POP. Cells from prolapsed mice expressed significantly decreased MMP‐2 (p < .05) and increased TIMP‐4 (p < .05). The results suggest changes to elastin structure rather than amounts in prolapsed mice as well as poor postpartum elastin turnover, resulting in accumulation of damaged elastic fibers leading to abnormal tropoelastin deposition. POP may thus, be the result of an inability to initiate the molecular mechanisms necessary to clear and replace damaged elastic matrix in pelvic floor tissues after vaginal birth.

Effect of petroleum gauze packing on the mechanical properties of suture materials

OBJECTIVE

To test the tensile properties of knotted suture made of 4 different suture materials and exposed to petroleum gauze.

STUDY DESIGN

We tested the tensile strength of United States Pharmacopeia size 0-0 gauge polydioxanone, polyglyconate, glycolide/lactide copolymer, and silk when exposed to petroleum packing or saline. Suture materials were randomized, and knots were tied and then evaluated via tensiometer to the point of knot failure.

RESULTS

A total of 285 knots were tied in 8 groups based on material and exposure to saline or petroleum gauze. We found that petroleum exposure knots failed at a mean of 116.7 N (SD = 31.5) and that saline soaked knots failed at 123.8 N (SD = 32.0). We conducted a 4 × 2 factorial analysis of variance, finding knots exposed to petroleum failed at a statistically significantly lower tensile strengths than saline soaked knots (p = 0.002).

CONCLUSION

Petroleum-exposed sutures fail at lower tensions than saline-exposed sutures.