High-magnification ICSI overcomes paternal effect resistant to conventional ICSI

Abstract

Previous studies have shown that repeated intracytoplasmic sperm injection (ICSI) failures can be caused by a paternal effect. Other studies have suggested that ICSI results are compromised if morphologically abnormal spermatozoa are injected into oocytes. This study was undertaken to evaluate the usefulness of a high-magnification optical system to select spermatozoa to be used for ICSI (high-magnification ICSI) in couples with repeated conventional ICSI failures. Couples with two or more previous conventional ICSI failures underwent an additional conventional ICSI attempt, followed by a high-magnification ICSI attempt. The outcomes of the two sequential attempts were compared. In 72 of these patients, sperm DNA integrity was assessed. In the whole group of 125 couples with repeated ICSI failures, high-magnification ICSI improved clinical outcomes (pregnancy, implantation, delivery and birth rates) without affecting biological outcomes (fertilization and cleavage rates, embryo morphology). The improvement of clinical ICSI outcomes was evident both in patients with an elevated degree of sperm DNA fragmentation and in those with normal sperm DNA status. It is concluded that high-magnification ICSI improves clinical outcomes in couples with previous repeated conventional ICSI failures.

The impact of paternal factors on cleavage stage and blastocyst development analyzed by time-lapse imaging—a retrospective observational study

“…Moreover, we could not find any deviations of early morphokinetics after fertilization with class I or class II/III spermatozoa. These observations confirm previous findings suggesting that the grade of sperm head vacuolization has no impact on the embryo outcome on day 3 [22,28,33,55]. Thus, the value of embryo selection prior to EGA remains questionable as the real developmental potency of the embryo cannot be properly estimated.…”

“…According to the growing body of literature, it is more and more obvious that large vacuoles are a sign of nuclear dysfunction, reflecting a failure of chromatin condensation and packaging [20][21][22][23][24][25][26][27]. It has been reported that the negative impact of large nuclear vacuoles (LNV) is perceptible after the onset of the EGA, leading to reduced blastocyst formation [28][29][30][31].…”

Poor-responder patients do not benefit from intracytoplasmic morphologically selected sperm injection

“…The process of finding spermatozoa without vacuoles is difficult and time-consuming [7,8,15,16,[30][31][32][33]. In addition, switching between the glass-bottomed dish that is appropriate for Nomarski microscopy and the plastic-bottomed dish that is appropriate for Hoffman modulation contrast requires additional time, delaying the injection procedure [16].…”

“…Several studies have reported that the IMSI procedure is positively associated with implantation and pregnancy rates [2][3][4][5][6][7][8][9]. In addition, recent meta-analysis showed that the IMSI procedure is associated with improved embryo quality [10], implantation [10,11] and pregnancy rates [10][11][12], as well as lower miscarriage rates [10,11] in couples with male factor [10][11][12] and previous ICSI failures [10,11].…”

The predictive value of high-magnification sperm morphology examination on ICSI outcomes in the presence of oocyte dysmorphisms

“…Several publications reported that the IMSI procedure is positively associated with pregnancy rates in couples with previous and repeated implantation failures [6,7,9,34] and in patients with an elevated degree of DNA fragmented spermatozoa [27,48]. Moreover, a recently published meta-analysis showed that the IMSI procedure is associated with improved embryo quality, implantation, pregnancy and miscarriage rates [40].…”