Morphological events in the primate endometrium in the presence of a preimplantation embryo, detected by the serum preimplantation factor bioassay

Abstract

Using PIF as a marker to detect early pregnancy in bonnet monkeys, we have shown that the embryo induces a pre-epithelial plaque type of reaction, increased angiogenesis and decidual reaction in the endometrium prior to implantation.

Expression of Endometrial Protein Kinase A During Early Pregnancy in Bonnet Monkeys (Macaca radiata)1

“…Preimplantation factor (PIF) was used as a surrogate marker of pregnancy. The usefulness of the PIF assay in detecting early pregnancy in bonnet monkeys has been shown previously by our group [25]. Our previous investigations have hinted that angiogenic, immunomodulatory, and proliferative pathways become operative even before intimate physical contact is established between the blastocyst and endometrium.…”

“…The control group included 9 nonmated animals. Early pregnancy was detected in mated bonnet monkeys on Day 6 after the estradiol peak using the PIF bioassay as reported elsewhere [25]. Briefly, heat-inactivated serum was incubated with a mixture of lymphocytes and platelets collected from blood of O Rh-positive male donors, anti-CD2 antibody, and rabbit complement.…”

“…PIF-positive animals were considered pregnant, while PIFnegative animals were considered nonpregnant. Circulatory hormonal profiles and histological features of endometria from the animals in both groups were described in our earlier study [25]. Endometrial biopsy specimens were collected on Day 6 after ovulation from pregnant (n ¼ 6) and nonpregnant (n ¼ 6) animals.…”

“…Our previous investigations have hinted that angiogenic, immunomodulatory, and proliferative pathways become operative even before intimate physical contact is established between the blastocyst and endometrium. Valuable information has been gained from these studies [24][25][26][27] on the expression pattern in gestational endometrium of those molecules (e.g., prolactin, alpha smooth muscle actin, transforming growth factor beta and its receptor, tumor necrosis factor and its receptor, etc.) previously investigated only for their hormonal regulation and/or possible role in endometrial receptivity.…”

Endometrial thickness and volume by three-dimensional ultrasound one week after embryo transfer to detect pregnancy

“…Jones and Fazleabas [15] have demonstrated that infusion of physiological doses of hCG in the uterine lumen of baboon results in an increase in number of small blood capillaries in the stroma of the endometrial functionalis what is an evidence that embryonic molecules influence precociously the endometrium in a paracrine manner to commence an angiogenic reaction. It was demonstrated in fecund monkeys [16,17] an increased vascularity and angiogenesis at the implantation site in the endometrium. A large number of small blood vessels could be seen just after implantation in the stroma underlying the luminal epithelium.…”