Dynamics of activities of matrix metalloproteinases-9 and -2, and the tissue inhibitors of MMPs in fetal fluid compartments during gestation and at parturition in the mare.

During late gestation in the mare, rapid fetal growth is accompanied by considerable placental growth and further invasion of the endometrium by microvilli. This growth requires extensive remodeling of the extracellular matrix (ECM). In early pregnancy, we know that matrix metalloproteinase (MMP)-9 and -2 are involved in the endometrial invasion during endometrial cup formation. The present study investigated whether MMPs are found in fetal fluids later in gestation and during parturition, and if there was a difference in their activities between normal and preterm delivery. Amniotic fluids were collected from pony mares during the latter half of gestation, and amniotic and allantoic fluids from pony and thoroughbred mares at foaling. The fluids were analysed for the activity of MMP-9 and -2, and TIMPs using zymography techniques. There was an increase (P = 0.002) in activity of latent MMP-9 when approaching normal foaling, and a decrease (P < 0.001) during foaling. MMP-2 activity did not change through gestation, or during foaling. When comparing samples from pregnancies resulting in preterm deliveries with samples from foaling mares, the activity of MMP-9 was lower (P < 0.001) and MMP-2 activity was higher (P = 0.004) during foaling than preceding preterm delivery. The activity of MMP-9 was lower (P = 0.002) prior to preterm delivery than before delivery of a live foal at term, whereas no difference (P = 0.07) was demonstrated for latent MMP-2 activity when comparing the same groups. The activity of TIMP-2 was higher (P < 0.001) in the pre-parturient period before normal foaling than preceding preterm delivery. These results suggest that MMPs may have a role as markers for high risk pregnancy in the mare.

Decreased serum levels of kisspeptin in early pregnancy are associated with intra-uterine growth restriction and pre-eclampsia.

OBJECTIVE: To investigate whether pregnancies with development of subsequent pre-eclampsia and intra-uterine growth restriction are associated with altered levels of kisspeptin in maternal serum in the second trimester. STUDY DESIGN: Retrospective case-control study of 16-20 week serum samples matched for duration of storage at -70 degrees C. Levels of kisspeptin were measured in serum from women with pregnancies with subsequent development of pre-eclampsia (n = 57), intra-uterine growth restriction (n = 118), and matched controls (n = 317). RESULTS: Serum kisspeptin levels were significantly lower in those women who subsequently developed pre-eclampsia than in controls [median (quartile range) 1109 (449) vs 1188 (365) pg/mL, p = 0.029] and in those with intra-uterine growth restriction [1164 (386) vs 1188 (365) pg/mL, p = 0.016]. CONCLUSIONS: Kisspeptin levels are lower in maternal serum in the second trimester, in pregnancies associated with placental dysfunction. The differences in kisspeptin are modest, so although not forming a single screening marker in pre-eclampsia and intra-uterine growth restriction, measurement of kisspeptin may be useful in combination with other markers. Understanding the role of kisspeptin in the establishment of the placenta may further our knowledge of the mechanisms underlying placental function.

Increased apoptosis and abnormal wound-healing responses in the heterozygous Pax6+/- mouse cornea.

PURPOSE: Corneal wound healing involves a cascade of interactions between the epithelium and stroma. Pax6 is upregulated, and early events include epithelial cell migration and apoptosis of superficial keratocytes. The mouse heterozygous Pax6 (Pax6+/-) corneal phenotype mimics human aniridia-related keratopathy (ARK), and some aspects of wound healing have been shown to be abnormal, including matrix metalloproteinase (MMP)-9 expression. The purpose of this study was to test whether the Pax6+/- genotype affects corneal wound-healing responses, including stromal cell apoptosis, epithelial cell migration rate, and MMP secretion in culture. METHOD: Pax6+/- and wild-type (Pax6+/+) mice were killed and their corneas wounded by epithelial debridement. Whole eyes were cultured in organ culture and corneal epithelial healing rates and keratocyte apoptosis were quantified by topical fluorescein staining and TUNEL, respectively. Dissociated corneal epithelial cells from Pax6+/- and wild-type mice were cultured, and the activities of secreted MMP-9 were determined by zymography. RESULTS: Wound-healing rates during the first 6 hours were significantly faster for larger wounds and for Pax6+/- corneas. Compared with wild-type, wounded Pax6+/- eyes showed significantly more stromal cell apoptosis, and cultured Pax6+/- corneal epithelial cells produced lower MMP-9 activity. CONCLUSIONS: The cumulative effect of abnormal wound-healing responses, characterized by increased stromal cell apoptosis and reduced levels of MMP-9 secretion may contribute to the corneal changes in the Pax6+/- mice. Possible contributions of elevated stromal cell apoptosis and other abnormal wound-healing responses to ARK are discussed.

Matrix metalloproteinase-2 and -9 secretion by the equine ovary during follicular growth and prior to ovulation.

Profound hormonally controlled tissue remodelling occurs in the equine ovary for follicle growth and development, and also for the alteration in follicle shape directed towards the ovulation fossa, the site where ovulation occurs. The aim of this study was to examine the spatial and temporal regulation of matrix metalloproteinases (MMP)-2 and MMP-9, important enzymes in tissue remodelling, during follicle growth, and ovulation. Using gelatin substrate zymography, we measured these MMPs in follicular fluid of large anovulatory follicles collected during spring transition, early dominant follicles (> 23 mm), and at oestrus in follicles approximately 3 days prior to ovulation, and post-hCG treatment when ovulation was predicted in approximately 4 h. The most abundant activity detected in follicular fluid was MMP-2, although there were no changes in secretion or activation in association with ovulation. The activity of MMP-9 was detected in lower amounts, with no changes prior to ovulation, although it decreased significantly (P < 0.05) post-hCG treatment. At oestrus, when different regions of the ovary were maintained in explant culture for 24 h, there were no significant changes in either MMP-2 or MMP-9 secretion by stromal tissues collected at the ovarian fossa, adjacent to the preovulatory follicle but away from the fossa, and a further site remote from the preovulatory follicle. Over this same time period, follicular progesterone (P < 0.01) and oestradiol (P < 0.05) increased significantly, although oestradiol tended to decrease after hCG administration. These findings indicate that MMP-2 and MMP-9 are not key acute regulators for the changes in follicle shape immediately prior to ovulation.