Objective Define the impact of prolapse mesh on the biomechanical properties of the vagina by comparing the prototype Gynemesh PS (Ethicon, Somerville, NJ) to 2 new generation lower stiffness meshes, SmartMesh (Coloplast, Minneapolis, MN) and UltraPro (Ethicon). Design A study employing a non-human primate model Setting University of Pittsburgh Population 45 parous rhesus macaques Methods Meshes were implanted via sacrocolpexy after hysterectomy and compared to Sham. Because its stiffness is highly directional UltraPro was implanted in two directions: UltraPro Perpendicular (less stiff) and UltraPro Parallel (more stiff), with the indicated direction referring to the blue orientation lines. The mesh-vaginal complex (MVC) was excised en toto after 3 months. Main Outcome Measures Active mechanical properties were quantified as contractile force generated in the presence of 120 mM KCl. Passive mechanical properties (a tissues ability to resist an applied force) were measured using a multi-axial protocol. Results Vaginal contractility decreased 80% following implantation with the Gynemesh PS (p=0.001), 48% after SmartMesh (p=0.001), 68% after UltraPro parallel (p=0.001) and was highly variable after UltraPro perpendicular (p =0.16). The tissue contribution to the passive mechanical behavior of the MVC was drastically reduced for Gynemesh PS (p=0.003) but not SmartMesh (p=0.9) or UltraPro independent of the direction of implantation (p=0.68 and p=0.66, respectively). Conclusions Deterioration of the mechanical properties of the vagina was highest following implantation with the stiffest mesh, Gynemesh PS. Such a decrease associated with implantation of a device of increased stiffness is consistent with findings from other systems employing prostheses for support.

Objective This study's goal was to compare elastin metabolism in the vagina of women with and without pelvic organ prolapse and to define the regulation of this process by hormone therapy (HT). Methods Eighty-seven histologically confirmed full-thickness vaginal biopsies were procured from study subjects at time of surgery. Premenopausal women with no prolapse served as controls. Women with prolapse were divided into 3 groups – premenopausal, postmenopausal not on HT and postmenopausal on HT. The epithelium was excised leaving the subepithelium, muscularis and adventitia for analyses. The elastin precursor, tropoelastin, was measured by immunoblotting and mature elastin protein via a desmosine crosslink radioimmunoassay. Matrix metalloproteinases (MMPs) -2, -9 were quantitated by gelatin zymography. Data were analyzed using Kruskal-Wallis test and post-hoc analysis using the Mann-Whitney U test. Results Tropoelastin (432%), mature elastin (55%), proMMP-9 (90%) and active MMP-9 (106%) were increased in women with prolapse relative to controls while active MMP-2 (41%) was decreased. Comparison of tropoelastin and mature elastin values obtained from the same women showed them to be independently regulated (r =0.19). Interestingly, the highest amount of both proteins occurred in postmenopausal patients not on HT. Conclusion Elastin metabolism is altered in the vagina of women with prolapse relative to controls suggesting that vaginal tissue is rapidly remodeling in response to mechanical stretch. The finding that elastin levels are highest in the absence of hormones warrants further investigation.