P-778 High altitude significantly affects pregnancy, implantation, live birth, and miscarriage rates in patients subjected to in vitro fertilization procedures with donated oocytes

Study question

Is high altitude an important factor that affects the clinical outcomes in patients subjected toin vitrofertilization with donated oocytes?

Summary answer

Pregnancy, implantation, and live birth rates are significantly impacted by paternal chronic hypoxia in IVF procedures involving egg donors.

What is known already

High altitude is characterized by low temperatures, high UV radiation, and a hypoxic environment that significantly affect human physiology, including endocrine, cardiovascular, metabolic, and reproductive functions. Hypoxia can affect male reproduction differently, such as at the hormonal level, during spermatogenesis and gene expression. More importantly, hypoxia can affect key events during early embryo development, with time of exposure being the determining factor in the stage of fertilization and embryonic development in mammals.

Study design, size, duration

The following work is a retrospective nonrandomized study based on data from 85 IVF donor egg cycles performed at high altitude (Huancayo-Peru, 3,300 meter above sea level;n = 42) and at sea level (Guayaquil-Ecuador;n = 43) between July 2019 and December 2020. The same protocols of culture and embryo classification were used in both assisted reproduction laboratories.

Participants/materials, setting, methods

Anonymous oocytes donors (18-29 years old) underwent physical, gynecological and psychological examinations, with no family histories of hereditary or chromosomal diseases reported. According to seminal samples, IVF or ICSI was elected as the insemination procedure. Extended embryo culture until blastocyst stage was done in all procedures. Pregnancy, implantation, live birth, and miscarriage rates were compared between groups.

Main results and the role of chance

Out of a total of 983 included oocytes, 529 corresponded to high level patients; and 454, to sea level patients. Fertilization rates (95.1% vs 92.1%) and good-quality embryos at day 3 (79.7% vs 83.8%) were similar between high altitude and sea level groups (P > 0.05). The number of transferred embryos in recipients at high altitude was significantly higher compared to those transferred in recipients at sea level (1.90±0.29 vs 1.62±0.49) (P < 0.05). Blastocyst formation rates (39.3% vs 44.3%), pregnancy rates (61.9% vs 71.4%), implantation rates (48.8% vs 64.7%) and live birth rates per embryo transfer (46.3% vs 65.7%) were significantly lower in the patients at high altitude compared to those from sea level (P < 0.05). Significantly more miscarriages were observed at high altitude (23.1% vs 6.5%) (P < 0.05). Seminal parameters were similar between both evaluated groups.

Limitations, reasons for caution

The retrospective nature of this study and the small sample size may be reason for caution.

Wider implications of the findings

The negative effect of high altitude on reproduction has been shown previously in men, hypoxia could cause a degeneration in the germinal epithelium that affects spermatogenesis. We show that paternal chronic hypoxia affects preimplantation embryonic development, pregnancy, implantation, live birth, and miscarriage rates in IVF procedures using donated oocytes.

Trial registration number

not applicable

P-273 Oocyte competence is affected by Body Mass Index in women undergoing in vitro fertilization procedures

Study question

Is body mass index (BMI) an important factor that affects oocyte competence in patients subjected to in vitro fertilization procedures?

Summary answer

High BMI affects oocyte competence, causing abnormal blastocyst development, and reduced clinical outcomes. Overweight and obesity women needed more oocytes to obtain a gestational sac.

What is known already

Overweight and obesity are systemic and tissue-specific conditions that lead to chronic inflammation and oxidative stress to produce an unregulated and persistent secretion of chemokines and cytokines, which are released into circulation inducing inflammatory responses in several tissues, including the ovaries. Cytokines, chemokines and adipokines play essential roles in steroidogenesis, follicular growth, cumulus expansion, and ovulation; however, alterations in their patterns of synthesis and secretion impair meiotic and cytoplasmic maturation of the oocyte, reducing its developmental competence for fertilization and pre-implantation development. Overweight or obese women had significantly lower clinical pregnancy and live birth rates and significantly higher miscarriage rates.

Study design, size, duration

The following work is a retrospective nonrandomized study that included a total of 1839 oocytes obtained from 201 IVF/ICSI non-donor cycles performed between January 2018 and December 2019.

Participants/materials, setting, methods

The oocytes were allocated according to BMI of patients in three groups: Normal group: 18.5-24.9 ( n =  608 oocytes), overweight group: 25.0-29.9 ( n =  832 oocytes) and obese group: ≥30.0 ( n =  399 oocytes). Extended embryo culture until blastocyst stage was done in all patients. Fertilization, development of blastocyst, transferred embryos, pregnancy and implantation rates were compared between groups. Number of oocytes needed to obtain a gestational sac (oocyte competence) were analyzed and compared by group.

Main results and the role of chance

Fertilization rates (87.7%, 85.3%, and 84.0%), and transferred embryos (1.84, 1.84, and 1.86) were similar between three evaluated groups. Blastocyst development rate (48.2%, 40.0%, and 40.1%), pregnancy rate (67.2%, 41.9%, and 39.5%), and implantation rate (53.7%, 31.8%, and 28.2%) were significantly reduced in women with overweight and obesity compared to women with normal weight ( P <  0.05). To obtain a gestational sac, 2.1 and 1.8 more oocytes were needed by obese and overweight women, respectively, than the control group, suggesting oocyte competence is negatively affected by higher BMI.

Limitations, reasons for caution

The retrospective nature of this study and the small sample size may be reasons for caution.

Wider implications of the findings

The findings in this study suggest that a weight above normal will progressively decrease oocyte competence thus, it is necessary to have a greater number of oocytes in patients with overweigh and obesity to have a gestational sac when compared with patients of normal weight.

Trial registration number

non applicable

Regional regulation of focal adhesion kinase after concentric and eccentric loading is related to remodelling of human skeletal muscle

AIMS

We assessed focal adhesion kinase (FAK) response to concentric (CON) vs eccentric (ECC) resistance training (RT) at two vastus lateralis (VL) sites, and the relationships between FAK, muscle protein synthesis (MPS) and morphological remodelling.

METHODS

Six young males trained both legs unilaterally 3 times/week for 8 weeks; one leg performed CON RT, the contralateral performed ECC RT. Muscle biopsies were collected after training from VL mid-belly (MID) and distal (distal) sites at 0, 4, 8 weeks. Focal adhesion kinase content and activation were evaluated by immunoblotting. MPS was assessed by deuterium oxide tracer; morphological adaptations were evaluated by ultrasound and DXA.

RESULTS

pY397-FAK 8 weeks levels were ~4-fold greater after ECC at the distal site compared to CON (P < .05); pY397FAK to total FAK ratio was greater in ECC vs CON at 4 (~2.2-fold, P < .05) and 8 weeks (~9-fold, P < .001) at the distal site. Meta-vinculin was found transiently increased at 4 weeks at the distal site only after ECC RT. ECC presented greater fascicle length (Lf) increases (10.5% vs 4%), whereas CON showed greater in pennation angle (PA) changes (12.3% vs 2.1%). MPS did not differ between exercise types or muscle sites at all time points. distal pY397-FAK and pY397-FAK/FAK values correlated to changes in Lf at 8 weeks (r = .76, P < .01 and r = .66, P < .05 respectively).

CONCLUSION

Focal adhesion kinase phosphorylation was greater at 8 weeks after ECC RT and was muscle region-specific. FAK activity correlated to contraction-dependent architectural remodelling, suggesting a potential role of FAK in orienting muscle structural changes in response to distinct mechanical stimuli.

ACE inhibition modifies exercise-induced pro-angiogenic and mitochondrial gene transcript expression

Skeletal muscle responds to endurance exercise with an improvement of biochemical pathways that support substrate supply and oxygen-dependent metabolism. This is reflected by enhanced expression of associated factors after exercise and is specifically modulated by tissue perfusion and oxygenation. We hypothesized that transcript expression of pro-angiogenic factors (VEGF, tenascin-C, Angpt1, Angpt1R) and oxygen metabolism (COX4I1, COX4I2, HIF-1α) in human muscle after an endurance stimulus depends on vasoconstriction, and would be modulated through angiotensin-converting enzyme inhibition by intake of lisinopril. Fourteen non-specifically trained, male Caucasians subjects, carried out a single bout of standardized one-legged bicycle exercise. Seven of the participants consumed lisinopril in the 3 days before exercise. Biopsies were collected pre- and 3 h post-exercise from the m. vastus lateralis. COX4I1 (P = 0.03), COX4I2 (P = 0.04) mRNA and HIF-1α (P = 0.05) mRNA and protein levels (P = 0.01) showed an exercise-induced increase in the group not consuming the ACE inhibitor. Conversely, there was a specific exercise-induced increase in VEGF transcript (P = 0.04) and protein levels (P = 0.03) and a trend for increased tenascin-c transcript levels (P = 0.09) for subjects consuming lisinopril. The observations indicate that exercise-induced expression of transcripts involved in angiogenesis and mitochondrial energy metabolism are to some extent regulated via a hypoxia-related ACE-dependent mechanism.