Predictive value of spindle retardance in embryo implantation rate

Abstract

Purpose We evaluated the relationship between meiotic spindle characteristics and in vitro fertilization cycle outcome. Methods Five hundred sixty-nine oocytes from 86 in vitro fertilization cycles were analyzed for fertilization and subsequent implantation rates. Oocytes were assessed for maturation status. The oocytes and embryos were cultured in sequential and nonsequential media (G Series, Vitrolife, Sweden) and incubated in 6% CO 2 , 5% O 2 at 37°C.Two hours following oocyte decumulation (38-39 h posthCG/GnRH administration) and prior to microinjection, the structure of the meiotic spindle was assessed using the Oosight Imaging System (CRI, UK). Results Four hundred fifty-six oocytes (80.5%) had a visible meiotic spindle, 82 (14.7%) had no meiotic spindle, and 31 (5.5%) were in telophase I. Oocytes exhibiting a meiotic spindle had a significantly higher fertilization rate and a lower rate of abnormal fertilization. Implantation data were obtained for 195 of the embryos transferred. The implantation rate for embryos derived from oocytes with a meiotic spindle was 32.9%, while in embryos originating from oocytes without a meiotic spindle and oocytes in telophase, this value dropped significantly (8.8 and 0%, respectively). To determine the correlation between retardance values and implantation rate for each oocyte, we established four groups, finding a range of retardance values with significantly higher implantation rates (27.5, 21, 29.3, and 53.8%, respectively). Conclusion Meiotic spindle imaging may be a valuable tool for prediction of oocyte quality, and retardance values of meiotic spindles, together with classical morphological classification, can be useful to select embryos with a higher implantation potential.

Does the meiotic spindle really predicts embryo implantation and live birth rates? An update

“…In the last published study (García-Oro et al , 2017), the implantation rates of each embryo were compared individually, according to the presence and retardance values of the MS. Embryos with visible MS had an implantation percentage of 32.9% and embryos with retardance values >1.61 nm had an implantation percentage of 53.8%.…”

“…The publications retrieved were analyzed and only those in which embryonic implantation rate was evaluated were selected. From 56 starting studies, we initially included 10 papers in this review (Chamayou et al , 2006; Shen et al , 2006; Madaschi et al , 2008; Kilani et al , 2009; Heindryckx et al , 2011; Kilani et al , 2011; Magli et al , 2011; Molinari et al , 2012; Korkmaz et al , 2014; García-Oro et al , 2017).…”

“…In a retrospective study published by our group (García-Oro et al , 2017), the presence and retardance of MS of 195 embryos transferred was analyzed individually. A higher implantation percentage in embryos with visible MS (32.9%) versus embryos without MS or in telophase (8.8% and 0%) was observed.…”

“…Numerous authors have focused their studies on evaluating different characteristics of the MS (presence/absence, position in respect to polar body, size, structure, refringence) and have tried to relate these characteristics to different parameters such as fertilization (de Almeida Ferreira Braga et al , 2008; Cohen et al . al., 2004; Konc et al , 2004; Madaschi et al , 2008; Moon et al , 2003; Rama Raju et al , 2007; Shen et al , 2006; Wang et al , 2001b), embryo quality and blastocyst formation (Wang et al , 2001a; Moon et al , 2003; Cohen et al , 2004; Chamayou et al , 2006; Fang et al , 2007; Rama Raju et al , 2007; Madaschi et al , 2008) and implantation rate (Chamayou et al , 2006; Shen et al , 2006; Madaschi et al , 2008; Kilani et al , 2009; Heindryckx et al , 2011; Kilani et al , 2011; Magli et al , 2011; Molinari et al , 2012; Korkmaz et al , 2014; García-Oro et al , 2017) among others. Published results, however, have been very heterogeneous.…”

Selection of competent oocytes by morphological criteria for assisted reproductive technologies

“…• Visualization ↑ ZP birefringence (Madaschi et al, 2009) ↑ fertilization rate (Braga et al, 2008;Garcia-Oro et al, 2017;Gonzalez-Ortega et al, 2016;Petersen et al, 2009;Rama Raju et al, 2007) ↑ normal pronuclei appearance (Petersen et al, 2009) ↑ cleavage rate (Petersen et al, 2009) ↑ Day 3 embryo quality (Petersen et al, 2009) ↑ embryo quality (Gonzalez-Ortega et al, 2016) ↑ blastocyst development (Braga et al, 2008;Garcia-Oro et al, 2017;Petersen et al, 2009;Rama Raju et al, 2007) ↑ implantation rate (Garcia-Oro et al, 2017;Madaschi et al, 2008) ↑ conception cycle (Gonzalez-Ortega et al, 2016) ↑ pregnancy rate (Konc et al, 2004;Madaschi et al, 2008) • Longer spindle length ↑ Fertilization success (Korkmaz et al, 2015) ↑ blastocyst formation (Rama Raju et al, 2007) • Misaligned meiotic spindle position ↑ Fertilization defect (Rienzi et al, 2003) • Localization to beneath or adjacent to PB ↑ Fertilization rate (Fang et al, 2007) • Higher retardance ↑ Better pronuclear score (Shen et al, 2006) ↑ blastocyst formation (Rama Raju et al, 2007) ↑ pregnancy rate (Shen et al, 2006) • Higher density ↑ Pregnancy rate (Kilani et al, 2009) • Normally appearing spindles ↑ Fertilization rate (Kilani et al, 2009;Tilia et al, 2020) ↑ Day 3 embryo development (Tilia et al, 2020) ↑ blastocyst quality (Tilia et al, 2020) ↑ euploid blastocyst number (Tilia et al, 2020) ↑ implantation rate (Kilani et al, 2009) ↑ pregnancy rate (Kilani et al, 2009) ↑ live birth rate (Kilani et al, 2009) • Fine aligned ↑ Embryo cleavage (Asa et al, 2017) ↑ embryo quality <...>…”