preimplantation-factor--synthetic and Abortion--Habitual

Recurrent pregnancy loss (RPL) affects 2-3% of couples. Despite a detailed work-up, the etiology is frequently undefined, leading to non-targeted therapy. Viable embryos and placentae express PreImplantation Factor (PIF). Maternal circulating PIF regulates systemic immunity and reduces circulating natural killer cells cytotoxicity in RPL patients. PIF promotes singly cultured embryos' development while anti-PIF antibody abrogates it. RPL serum induced embryo toxicity is negated by PIF. We report that PIF rescues delayed embryo development caused by <3 kDa RPL serum fraction likely by reducing reactive oxygen species (ROS). We reveal that protein disulfide isomerase/thioredoxin (PDI/TRX) is a prime PIF target in the embryo, rendering it an important ROS scavenger. The 16F16-PDI/TRX inhibitor drastically reduced blastocyst development while exogenous PIF increased >2 fold the number of embryos reaching the blastocyst stage. Mechanistically, PDI-inhibitor preferentially binds covalently to oxidized PDI over its reduced form where PIF avidly binds. PIF by targeting PDI/TRX at a distinct site limits the inhibitor's pro-oxidative effects. The >3kDa RPL serum increased embryo demise by three-fold, an effect negated by PIF. However, embryo toxicity was not associated with the presence of putative anti-PIF antibodies. Collectively, PIF protects cultured embryos both against ROS, and higher molecular weight toxins. Using PIF for optimizing in vitro fertilization embryos development and reducing RPL is warranted.

Topics: Abortion, Habitual; Animals; Cattle; Embryonic Development; Female; Humans; Mice; Oxidative Stress; Peptides; Pregnancy; Pregnancy Proteins

Embryo-secreted preimplantation factor (PIF) is necessary for, and its concentration correlates with, embryo development in humans by promoting implantation and trophoblast invasion. Synthetic PIF (sPIF) modulates systemic immunity and is effective in autoimmune disease models. sPIF binds monocytes and activated T and B cells, leading to immune tolerance without suppression. This study examined the effect of sPIF on natural killer (NK) cell cytotoxicity in 107 consecutive nonselected, nonpregnant patients with recurrent pregnancy loss (RPL) and 26 infertile IVF patients (controls). The effects of sPIF, intravenous gamma immunoglobulin (Ig), Intralipid and scrambled PIF (PIFscr; negative control) on NK cell cytotoxicity to peripheral-blood cells were compared by flow cytometry of labelled-K562 cell cytolysis. The effects of sPIF and PIFscr on whole-blood NKCD69+ expression were also compared. In patients with RPL, sPIF inhibited NK cell cytotoxicity at doses of 2.5 and 25ng/ml (37% and 42%) compared with PIFscr (18%; P<0.001), regardless of the proportion of peripheral-blood NKCD56+ cells to lymphocytes. Pre-incubation of blood from infertile patients with sPIF for 24h decreased NKCD69+ expression versus incubatino with PIFscr (P<0.05). In conclusion, sPIF inhibits NK cell cytotoxicity by reducing NKCD69 expression, suggesting a significant role in RPL patients. There is a continuous search to identify safe and effective agents to counteract recurrent pregnancy loss (RPL). Preimplantation factor (PIF) secreted by the embryo at the 2-cell stage is present throughout viable pregnancy but absent in nonviable pregnancy. Its immunomodulatory (not suppressive) effects promote embryo acceptance and maintenance by mother/host, control inflammation, facilitate uterine environment and placental embedding. Synthetic PIF (sPIF) was used to complete PIF's role as a targeted, safe treatment for immune-based RPL. Previous reports showed sPIF's significant protective systemic effect against maternal factors present in RPL serum. Herein is examined sPIF's ability to inhibit the local protective toxicity induced by natural killer (NK) immune cells in a representative number of RPL patients. When elevated in blood, NK cells are associated with RPL. Low-dose physiological sPIF was highly effective to inhibit NK cell toxicity. Side-by-side comparison showed that sPIF is equally effective at a lower dose than intravenous gamma immunoglobulin or Intralipid treatment currently us

Topics: Abortion, Habitual; Adult; Antigens, CD; Antigens, Differentiation, T-Lymphocyte; Emulsions; Female; Humans; Immunoglobulins, Intravenous; Killer Cells, Natural; Lectins, C-Type; Lymphocyte Activation; Peptides; Phospholipids; Pregnancy; Soybean Oil

Preimplantation factor (PIF) is secreted by viable mammalian embryos and promotes implantation and trophoblast invasion. Whether PIF also has a direct protective or promoting effect on the developing embryo in culture is unknown. This study examined the protective effects of synthetic PIF (sPIF) on embryos cultured with embryo toxic serum (ETS) from recurrent pregnancy loss patients (n=14), by morphological criteria at 72 h of culture, and determined sPIF-promoting effect on singly cultured bovine IVF embryo development. sPIF negated the ETS-induced effect by increasing mouse blastocyst rate versus other embryonic stages (odds ratio (OR) 2.01, 95% confidence intervals (CI) 1.14-3.55, chi-squared=12.74, P=0.002), increased blastocyst rate (39.0% versus 23.7% ETS alone) and lowered embryo demise rate (11.0% versus 28.8%, OR 0.24, 95% CI 0.11-0.54), which was not replicated by scrambled PIF or the control. sPIF added to bovine embryos for 3 days promoted development at day 7 of culture (11% versus 0%, chi-squared=4.0, P=0.045). In conclusion, sPIF prevented embryo demise caused by exposure to ETS and promoted development of singly cultured bovine IVF embryos following short-term exposure. sPIF-based therapy for reducing recurrent pregnancy loss and improving lagging cultured IVF embryo development should be explored.

Topics: Abortion, Habitual; Animals; Blastocyst; Cattle; Embryo Culture Techniques; Embryo Implantation; Embryo, Mammalian; Embryonic Development; Female; Fertilization in Vitro; Humans; Mice; Peptides; Pregnancy