title: Ovine multiparity is associated with diminished vaginal muscularis, increased elastic fibres and vaginal wall weakness: implication for pelvic organ prolapse.
abstract: Pelvic Organ Prolapse (POP) is a major clinical burden affecting 25% of women, with vaginal delivery a major contributing factor. We hypothesised that increasing parity weakens the vagina by altering the extracellular matrix proteins and smooth muscle thereby leading to POP vulnerability. We used a modified POP-quantification (POP-Q) system and a novel pressure sensor to measure vaginal wall weakness in nulliparous, primiparous and multiparous ewes. These measurements were correlated with histological, biochemical and biomechanical properties of the ovine vagina. Primiparous and multiparous ewes had greater displacement of vaginal tissue compared to nulliparous at points Aa, Ap and Ba and lower pressure sensor measurements at points equivalent to Ap and Ba. Vaginal wall muscularis of multiparous ewes was thinner than nulliparous and had greater elastic fibre content. Collagen content was lower in primiparous than nulliparous ewes, but collagen organisation did not differ. Biomechanically, multiparous vaginal tissue was weaker and less stiff than nulliparous. Parity had a significant impact on the structure and function of the ovine vaginal wall, as the multiparous vaginal wall was weaker and had a thinner muscularis than nulliparous ewes. This correlated with "POP-Q" and pressure sensor measurements showing greater tissue laxity in multiparous compared to nulliparous ewes.
authors.affiliation: The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, 3168, Australia.|Monash University, Department of Obstetrics and Gynaecology, Clayton, Victoria, 3168, Australia.
authors.forename: Stuart
authors.initials: S
authors.lastname: Emmerson
authors.affiliation: Monash Health, Clayton, Victoria, 3168, Australia.
authors.forename: Natharnia
authors.initials: N
authors.lastname: Young
authors.affiliation: Monash University, Department of Obstetrics and Gynaecology, Clayton, Victoria, 3168, Australia.|Monash Health, Clayton, Victoria, 3168, Australia.
authors.forename: Anna
authors.initials: A
authors.lastname: Rosamilia
authors.affiliation: School of Computer Science, Engineering and Mathematics, Flinders University, Bedford Park, South Australia 5042, Australia.
authors.forename: Luke
authors.initials: L
authors.lastname: Parkinson
authors.affiliation: CSIRO Manufacturing, Clayton, Victoria, 3168, Australia.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Edwards
authors.affiliation: CSIRO Manufacturing, Clayton, Victoria, 3168, Australia.
authors.forename: Aditya V
authors.initials: AV
authors.lastname: Vashi
authors.affiliation: The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, 3168, Australia.|Monash University, Department of Obstetrics and Gynaecology, Clayton, Victoria, 3168, Australia.
authors.forename: Miranda
authors.initials: M
authors.lastname: Davies-Tuck
authors.affiliation: CSIRO Manufacturing, Clayton, Victoria, 3168, Australia.
authors.forename: Jacinta
authors.initials: J
authors.lastname: White
authors.affiliation: MicroImaging, Hudson Institute of Medical Research, Clayton, Victoria, 3168, Australia.
authors.forename: Kirstin
authors.initials: K
authors.lastname: Elgass
authors.affiliation: MicroImaging, Hudson Institute of Medical Research, Clayton, Victoria, 3168, Australia.
authors.forename: Camden
authors.initials: C
authors.lastname: Lo
authors.affiliation: School of Computer Science, Engineering and Mathematics, Flinders University, Bedford Park, South Australia 5042, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Arkwright
authors.affiliation: Monash University, Department of Obstetrics and Gynaecology, Clayton, Victoria, 3168, Australia.|CSIRO Manufacturing, Clayton, Victoria, 3168, Australia.
authors.forename: Jerome A
authors.initials: JA
authors.lastname: Werkmeister
authors.affiliation: The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, 3168, Australia.|Monash University, Department of Obstetrics and Gynaecology, Clayton, Victoria, 3168, Australia.
authors.forename: Caroline E
authors.initials: CE
authors.lastname: Gargett
mesh_terms: D000818:Animals; D004547:Elastic Tissue / Q000473:pathology*; D005260:Female; D009130:Muscle, Smooth / Q000473:pathology*; D010298:Parity / Q000502:physiology*; D056887:Pelvic Organ Prolapse / Q000473:pathology*; D011247:Pregnancy; D012756:Sheep; D014621:Vagina / Q000473:pathology*