GnRH agonist trigger in poor prognosis patients undergoing a multicycle approach through DuoStim or consecutive stimulations: a SWOT analysis.

PURPOSE OF REVIEW: Identify the most recent and significant evidence regarding the ovulation trigger within the framework of a multicycle approach through DuoStim, providing valuable insights for improving treatment strategies in patients with a poor prognosis. RECENT FINDINGS: The trigger method plays a pivotal role in optimizing in-vitro fertilization (IVF) stimulation, influencing oocyte retrieval and maturation rates, as well as follicle recruitment in consecutive ovarian stimulations such as double stimulation. Decision-making involves multiple factors and, while guidelines exist for conventional stimulation, specific recommendations for the multicycle approach are not well established. SUMMARY: The different methods for inducing oocyte maturation underscore the need for personalization of IVF protocols. The GnRH agonist trigger induces rapid luteolysis and establishes favorable hormonal conditions that do not adversely affect the recruitment of consecutive follicular waves in the context of DuoStim. It serves as a valid alternative to hCG in freeze-all cycles. This strategy might enhance the safety and flexibility of ovarian stimulations with no impact on oocyte competence and IVF efficacy.

Effect of exogenous xylanase on rumen in vitro gas production and degradability of wheat straw.

The objective of this study was to determine effects of xylanase on in vitro gas production (GP) and in sacco degradability of wheat straw. Rumen fluid was obtained from three Mongolian native goats fitted with permanent rumen cannulas. The trial consisted of five doses (0, 0.5, 1.0, 1.5, 2.0 µL/g of substrate) of a commercial xylanase (Dyadic® xylanase PLUS, Dyadic International, Inc., Jupiter, FL, USA). For the in sacco degradability, different levels of xylanase enzyme were added directly onto 2 g of wheat straw in nylon bags and incubated in the rumen for 3, 6, 12, 24 and 48 h to estimate degradability of wheat straw. Total GP increased (P < 0.001) at all times of incubation at intermediate levels of xylanase. Methane production had a similar pattern at 3 and 12 h of incubation; increased linearly at 24 h of incubation, and was unaffected at 6 and 48 h of incubation. Rumen NH3 -N concentration increased linearly at 3 h and the highest values were observed with intermediate enzyme levels. All ruminal volatile fatty acids increased linearly with intermediate levels of the fibrolytic enzyme. The in sacco rate of dry matter degradation decreased linearly (P = 0.020) with increasing enzymes. Intermediate levels of xylanase improved rumen kinetic fermentation and degradability. The outcome of this research indicated that the application of xylanase enzyme could improve in vitro GP fermentation of wheat straw.

Impact of final oocyte maturation using gonadotropin-releasing hormone agonist triggering and different luteal support protocols on endometrial gene expression.

OBJECTIVE: To use microarray technology to analyze endometrial gene expression after gonadotropin-releasing hormone agonist (GnRH-a) triggering with four different protocols of luteal support in comparison with results obtained after a human chorionic gonadotropin (hCG) trigger. DESIGN: Prospective, randomized, controlled trial. SETTING: University-affiliated private assisted-reproduction center. PATIENT(S): 25 healthy oocyte donors undergoing controlled ovarian stimulation. INTERVENTION(S): On day of final oocyte maturation, randomization to [1] GnRH-agonist triggering and luteal support with oral estradiol (2 mg/8 hours) and vaginal progesterone (200 mg/12 hours), [2] GnRH-a and a daily dose of 150 IU of recombinant LH from oocyte pickup, [3] GnRH-a and a single bolus of 60 µg of recombinant hCG on oocyte pickup, [4] GnRH-a and three doses of 20 µg of recombinant hCG separated by 48 hours, or [5] 250 µg of recombinant hCG for trigger and standard luteal support; with endometrial biopsy samples collected 7 days after triggering. MAIN OUTCOME MEASURE(S): Gene expression using the Endometrial Receptivity Array (ERA) and pathway and network analysis of study groups 1-4 compared with controls (group 5). RESULT(S): The 56 genes in group 1 (25 up-regulated and 31 down-regulated) exhibited altered expression compared with the 36 genes from group 2 (13 up-regulated and 23 down-regulated), 44 from group 3 (28 up-regulated and 16 down-regulated), and 30 (20 up-regulated and 10 down-regulated) from group 4. CONCLUSION(S): Differences were seen in endometrial gene expression related to the type of ovulation trigger and luteal support. However, gene expression after the GnRH-a trigger and modified luteal support adding LH/hCG activity more closely resembles the pattern seen in the hCG group. CLINICAL TRIAL REGISTRATION NUMBER: EudraCT 2011-003250-34.

Effect of GnRH agonist and hCG treatment on VEGF, angiopoietin-2, and VE-cadherin: trying to explain the link to ovarian hyperstimulation syndrome.

This study evaluated the differentially modulated expression of vascular mediators in oocyte donors after hCG vs. GnRHa triggering, trying to understand ovarian hyperstimulation syndrome pathophysiology. Donors who received GnRH agonist triggering showed a statistically significant decrease in vascular endothelial growth factor in follicular fluid and in mRNA expression in granulosa cells, with no differences in angiopoietin 2 and vascular endothelial cadherin levels in serum or follicular fluid. This differential regulation of vascular endothelial growth factor by hCG might explain the higher likelihood of ovarian hyperstimulation syndrome following hCG administration compared with GnRH agonists.

Low-dose human chorionic gonadotropin versus estradiol/progesterone luteal phase support in gonadotropin-releasing hormone agonist-triggered assisted reproductive technique cycles: understanding a new approach.

It remains unclear how GnRH agonist (GnRHa) triggering affects the luteal phase, so we investigated the luteal phase after GnRHa triggering, supported with conventional E(2)/P with or without low-dose hCG. E(2)/P support, compared with low-dose hCG, induced a shorter luteal phase (11.2 ± 1.1 vs. 15.0 ± 1.6 days) and fewer subjective complaints (0 vs. 42%), whereas hCG caused more free fluid accumulation and enlarged ovaries than E(2)/P alone. Steroids and low-dose hCG differentially affected corpus luteum function, ovarian size, free fluid accumulation, and patient comfort.

Differential regulation of VEGF after final oocyte maturation with GnRH agonist versus hCG: a rationale for OHSS reduction.

In a prospective cohort study, we compared the effect of hCG and GnRH agonist triggering of final oocyte maturation on vascular endothelial growth factor production. Vascular endothelial growth factor follicular fluid concentration was significantly lower in response to GnRH agonist versus hCG, which may partially explain the absence of OHSS in these of women.