Visualization of meiotic spindle and subsequent embryonic development in in vitro and in vivo matured human oocytes

Purpose The goals of this study are to analyze the clinical pregnancy rate as a function of the pre-intracytoplasmic sperm injection (ICSI) oocyte spindle angle and determine factors which can be associated with different spindle angles, if clinically relevant. Methods Fifty-eight patients, who underwent their first ICSI cycle from January to December 2013, were included. Eight hundred thirty oocytes were collected, and 648 were metaphase II (MII) on retrieval day. Spindles were characterized in terms of visibility and position in relation to the first polar body (PB). Oocytes were separated into four groups based on angle: (group 1, n = 297) 0°-29°; (group 2 n = 212) 30°-89°; (group 3, n = 72) ≥90°; and those with no visible spindle (group 4, n = 67). Results The rate of blastocyst development was associated with the spindle angle (p = 0.002). The rate of good quality blastocysts were as follows: group 1 (42%), group 2 (30%), group 3 (35%), and group 4 (19%) (p = 0.02). Pregnancy and live birth rates were also affected (p = 0.007 and p = 0.046, respectively). Antral follicle count (AFC) (p = 0.001), total FSH stimulating dose (p = 0.0001), and peak serum estradiol level (p = 0.0001) were associated with spindle angle grouping. Miscarriage rates trended different (p = 0.07). On the other hand, day 3 follicle-stimulating hormone (FSH) levels and female and male age were not associated with spindle angle grouping. Conclusions Embryos resulting from oocytes with pre-ICSI spindle angles between 0°and 29°were associated with better blastocyst, pregnancy, live birth, and miscarriage rates when compared to oocytes that had no visible spindle. Low ovarian reserve and excessive stimulation were also associated with lack of spindle and therefore lower pregnancy outcomes.

Section: Discussionmentioning

confidence: 99%

Relationship between pre-ICSI meiotic spindle angle, ovarian reserve, gonadotropin stimulation, and pregnancy outcomes

Mahfoudh¹,

Moon

Henderson³

et al. 2017

“…Pregnancy rate was also strongly correlated with the retardance of meiotic spindle [29]. The magnitude of the retardance of the polarized light provides an indication of the density, high order alignment, or thickness of a birefringent object [28,29]. Our results showed that the areas and lengths of the spindles of early cleaving oocytes were greater than those in late cleaving oocytes.…”

Section: Discussionmentioning

confidence: 51%

“…Additionally, the light retardance by human oocyte spindles was positively correlated with the pronuclear score after ICSI [28]. Pregnancy rate was also strongly correlated with the retardance of meiotic spindle [29]. The magnitude of the retardance of the polarized light provides an indication of the density, high order alignment, or thickness of a birefringent object [28,29].…”

Section: Discussionmentioning

confidence: 99%

Relationship between meiotic spindle characteristics in human oocytes and the timing of the first zygotic cleavage after intracytoplasmic sperm injection

Tomari

Honjou²,

Nagata³

et al. 2011

Purpose To investigate the relationship between meiotic spindle characteristics in human oocytes and the timing of the first zygotic cleavage after intracytoplasmic sperm injection (ICSI). Methods Zygotes that had cleaved to two-cell stage by 27 h post-ICSI were classified as early cleaving and the remainder as late cleaving. Meiotic spindle parameters previously imaged using the PolScope were compared between the two groups. Results Of 384 embryos, 163 were classed as early cleaving and 221 as late cleaving. The rate of blastocyst formation or pregnancy by Day 2 embryo transfer was significantly higher following early cleavage than after late cleavage (52.4% vs. 24.4% or 32.6% vs. 11.4%). Spindle areas (108.0 vs. 89.8 μm 2 ), lengths (14.7 vs. 13.4 μm) and PolScope retardance were also significantly greater in the early cleaving group. Conclusions Meiotic spindle parameters determine the timing of the first zygotic cleavage and are strong indicators of human embryo developmental potential.

“…The percentage of absent or invisible spindles found by different authors varies from 9 to 22% [19,26,29,32], though some authors found higher percentages [24]. Correlations have been described between the presence and absence of the meiotic spindle and fertilization rates [19,[21][22][23][24]26].…”

Section: Spindle Presence/absencementioning

confidence: 98%

Predictive value of spindle retardance in embryo implantation rate

García-Oro¹,

Rey²,

Rodriguez³

et al. 2017

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.