The fatty acid composition in follicles is related to the developmental potential of oocytes up to the blastocyst stage: a single-centre cohort study

Abstract

Background Advanced maternal age and obesity are associated with impaired female fertility. Moreover, fatty acids (FA) in follicular fluid (FF) play important roles in oocyte maturation and embryo development. However, the effects of body mass index (BMI), age, and FF FA composition on embryo development between days 3 and 5 and blastocyst stage on day 5 are still unclear. Methods This study included 138 patients undergoing assisted reproductive technology (ART), which were divided into three BMI groups (18.5–24.9 kg/m2 vs. 25.0–29.9 kg/m2 vs. ≥ 30.0 kg/m2) and three age-related groups (20–30 years vs. 31–34 years vs. ≥ 35 years) which were compared for ART outcomes. Further, observations were divided into quartiles based on either of three parameters related to embryo outcome, i.e. (i) embryos developing between days 3 and 5 (ED3-5) and (ii) expanded blastocysts on day 5 (EB5), both expressed proportionally to the number of oocytes with two pronuclei (2PN), as well as (iii) the embryo utilization rate (EUR). Proportions of FF FA were then compared between Q1 and Q4, representing the quartile with the worst vs. the best embryo outcome, respectively. Finally, regression models were created to assess the relationships between BMI, age, FF total FA (TFA) concentration, relative proportions of specific FA and embryo outcome. Results Patients of Q1 had higher proportions of FF C20:5n-3, C22:6n-3 and total n-3 PUFA than Q4 patients. Furthermore, Q4 patients tended to be younger than Q1 patients. Within the whole cohort, the proportion of C20:5n-3 negatively correlated with ED3-5/2PN and EUR, while EB5/2PN tended to be negatively correlated with age. Regression models within the overweight and obese group confirmed the negative relation between C20:5n-3 and ED3-5/2PN, but also indicated additional associations: C18:1n-9 and C20:4n-6 were positively associated with ED3-5/2PN and EUR, respectively while the proportion of C18:0 was negatively associated with EUR. Conclusion The proportions of n-3 PUFA, particularly C20:5n-3 and C22:6n-3 were reduced in the patients’ quartile with the best embryo outcome. This group of patients was also younger. However, the embryo quality parameters of overweight/obese patients were not associated with age but were positively associated with FF C18:1n-9 and negatively with the proportions of C18:0 or C20:5n-3. Trial registration This study’ registration number was B670201627735.

Effect of medroxyprogesterone acetate dose in progestin-primed ovarian stimulation on pregnancy outcomes in poor ovarian response patients with different body mass index levels

“…Previous studies showed that obese patients often had poor IVF outcomes related to oocyte quality ( 8 , 30 ). A single-center cohort study showed that embryo quality parameters in high BMI patients were not age-related but correlated with fatty acids in follicular fluid ( 31 ). A randomized controlled trial demonstrated that using MPA in the PPOS protocol can increase lipid levels in follicular fluid, promoting follicular development and oocyte maturation ( 32 ).…”

Composition and distribution of fatty acids in various lipid fractions in serum and follicular fluid of women undergoing assisted reproductive technology

“…Indeed, only unfertilized and discarded human oocytes would be available for such studies [25,26]; while from a technical point of view, lipid mass of a single oocyte is well below the sensitivity of the analytical method [25]. Consequently, the analysis of compounds (such as lipids and FA) in the follicular micro-environment has been proposed as an alternative tool to associate with oocyte and embryo outcome [2][3][4][5][6][7]. Generally, serum lipid classes clustered with their counterparts in the FF in a PCA including the proportions of all identified FA from all lipid classes as well as from the non-fractionated extract.…”

“…The follicular fluid (FF), the milieu in which the oocyte matures [1], among others constitutes of fatty acids (FA) which have been associated with oocyte maturation, embryo development and subsequent pregnancy [2][3][4][5][6][7]. Indeed, FF FA play important roles as cellular energy sources, structural components of membranes, and precursors for prostaglandins and steroid synthesis [8].…”

“…Indeed, FF FA play important roles as cellular energy sources, structural components of membranes, and precursors for prostaglandins and steroid synthesis [8]. Several studies have reported direct associations of FF FA in total fats or a specific lipid fraction with reproductive performance [2][3][4][5][6][7]. Further, FF is the discarded material when oocytes are aspirated from patients undergoing assisted reproductive technology (ART).…”

Arachidonic acid metabolism in health and disease

“…The fatty acid composition of follicular fluid is related to oocyte maturation and quality. A study showed that the fatty acid composition in follicles is related to the developmental potential of oocytes up to the blastocyst stage 202 . The fatty acid composition in follicular fluid can reflect the oocyte cytoplasm under assisted reproductive therapy (ART) 203 .…”