PreImplantation Factor (PIF) correlates with early mammalian embryo development-bovine and murine models

<p>Abstract</p> <p>Background</p> <p>PreImplantation Factor (PIF), a novel peptide secreted by viable embryos is essential for pregnancy: PIF modulates local immunity, promotes decidual pro-adhesion molecules and enhances trophoblast invasion. To determine the role of PIF in post-fertilization embryo development, we measured the peptide's concentration in the culture medium and tested endogenous PIF's potential trophic effects and direct interaction with the embryo.</p> <p>Methods</p> <p>Determine PIF levels in culture medium of multiple mouse and single bovine embryos cultured up to the blastocyst stage using PIF-ELISA. Examine the inhibitory effects of anti-PIF-monoclonal antibody (mAb) added to medium on cultured mouse embryos development. Test FITC-PIF uptake by cultured bovine blastocysts using fluorescent microscopy.</p> <p>Results</p> <p>PIF levels in mouse embryo culture medium significantly increased from the morula to the blastocyst stage (ANOVA, P = 0.01). In contrast, atretic embryos medium was similar to the medium only control. Detectable - though low - PIF levels were secreted already by 2-cell stage mouse embryos. In single bovine IVF-derived embryos, PIF levels in medium at day 3 of culture were higher than non-cleaving embryos (control) (P = 0.01) and at day 7 were higher than day 3 (P = 0.03). In non-cleaving embryos culture medium was similar to medium alone (control). Anti-PIF-mAb added to mouse embryo cultures lowered blastocyst formation rate 3-fold in a dose-dependent manner (2-way contingency table, multiple groups, X2; P = 0.01) as compared with non-specific mouse mAb, and medium alone, control. FITC-PIF was taken-up by cultured bovine blastocysts, but not by scrambled FITC-PIF (control).</p> <p>Conclusions</p> <p>PIF is an early embryo viability marker that has a direct supportive role on embryo development in culture. PIF-ELISA use to assess IVF embryo quality prior to transfer is warranted. Overall, our data supports PIF's endogenous self sustaining role in embryo development and the utility of PIF- ELISA to detect viable embryos in a non-invasive manner.</p

Embryo Transfer: Economic Implications for the Dairy Industry

Developments in nonsurgical embryo transfer have made commercial application for beef and dairy cows feasible. DHIA records were used to determine milk production variability within dairy herds. The top 10 percent of cows within herds produced 43 percent more milk that the herd average compared with 49 percent below herd average for the bottom 10 percent. The top 10 percent of cows within DHIA herds were assumed to be embryo donors for the remainder of the cows in DHIA herds. Economic implications were assessed for the U.S. dairy industry by region. Feed required to support the higher milk production level increased 296 kg while net income increased $161 per cow per year (assuming no affect on milk price). Aggregate milk production would increase by 6 percent if cow numbers remained the same. Approximately 6 percent fewer cows would be required to produce the present level of milk production if less efficient producers were forced to stop producing (11 percent of non-DHIA herds). Dairymen could pay$533 for each 1000 kg increase in milk production potential for an embryo transplant heifer calf at current milk and feed prices

Isolation and culture of porcine adipose tissue-derived somatic stem cells.

Adipose tissue-derived stem cells (ASCs) have been described for a number of laboratory animals and humans. Improved culture conditions and cellular characteristics of ASCs have been identified. ASCs can self-renew and differentiate into multiple tissue lineages. Further characterization of ASCs in this manner could enhance the isolation and purification of a population of mesenchymal stem cells (MSCs) from easily obtainable adipose tissue. These stem cell populations from domestic animals, which make attractive models for transplantation studies, will be valuable for the evaluation of their efficacy in tissue regeneration applications in the future. These cells may also represent a population more easily reprogrammable during somatic cell nuclear transfer and thus expedite the development of transgenic animals for models and production of valuable pharmaceutical proteins

Effects of melatonin and thyrotropin releasing hormone on mares during the nonbreeding season.

Two hormonal treatments, chosen for their effectiveness in other seasonally breeding species, were tested in mares during the nonbreeding season to determine if they could induce ovarian activity and estrus during the winter. Of 15 functionally anestrous (anovulatory) mares, five received intravaginal, polyurethane sponges containing .75 g of melatonin on December 16; fresh sponges containing melatonin were inserted weekly until February 3. These mares also received daily injections of saline. Five other mares received daily im injections of 100 micrograms of thyrotropin-releasing hormone (TRH) and control sponges during the treatment period. The remaining five mares were given control injections and control sponges throughout the experiment. Intravaginal sponges containing melatonin increased (P less than .05) concentrations of melatonin in systemic plasma for at least 7 d to levels at least 10-fold higher than those expected during the nighttime hours. The TRH significantly increased concentrations of thyroid-stimulating hormone within 60 min after injection, whereas there was no detectable increase in concentrations of prolactin after TRH. Ovarian size in all three groups of mares was increased (P less than .05) shortly after the onset of the treatment regimens. Moreover, there were surges in concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in plasma closely associated with sponge insertion and(or) injection of TRH or saline in mares of all groups. Due to the temporal correlation of gonadotropin surges and sponge insertion, we suspect that placement of intravaginal sponges may have caused the release of LH and FSH, perhaps through a neuroendocrine reflex. These surges in gonadotropins may have mediated the ovarian response. Alternatively, ovarian activity may have been stimulated by an unknown environmental factor, a possibility that was not examined in this study. Melatonin or TRH did not augment or inhibit this nonspecific response

Testosterone effects on mares during synchronization with altrenogest: FSH, LH, estrous duration and pregnancy rate.

Twelve mares fed altrenogest for 14 d were used to study the effects of a single injection of testosterone propionate on concentrations of follicle-stimulating hormone (FSH) during diestrus, and to relate the normal and perturbed patterns of FSH secretion to subsequent estrous characteristics and fertility. Seven of 12 mares received testosterone propionate at 200 micrograms/kg of body weight on d 5 of progestogen feeding. Mares were teased and blood samples were drawn daily; all mares were artificially inseminated at the first estrus after progestogen treatment. Testosterone propionate treatment caused a 50% reduction in concentration of FSH in plasma within 24 h, and this effect persisted through 48 h after injection. Within 4 d after the suppression of FSH secretion, concentrations of FSH rebounded and were significantly elevated compared with control values during the last 4 d of progestogen feeding. Testosterone propionate at this dosage also elicited estrous behavior in five of seven treated mares within 24 h after injection. After withdrawal of progestogen feeding, the interval to onset of estrus, duration of estrus, and magnitude of the luteinizing hormone peak were similar between groups (P greater than .05). Six of seven treated mares and three of five control mares became pregnant to breeding on the first estrus after progestogen treatment. Because manipulation of the normal pattern of FSH secretion during diestrus did not affect estrous characteristics or fertility of the subsequent estrus, such treatment may have potential as a means of synchronizing FSH surges during diestrus in the mare