Assisting in vitro fertilization by manipulating cumulus-oocyte-complexes either mechanically or enzymatically does not prevent IVF failure

Abstract

Objective: This prospective study was set up in order to analyze whether additional treatment (cutting off supernumerous cumulus cells; adding hyaluronidase) of the cumulus-oocyte-complex (COC) would help to improve treatment outcome. Material and Methods:COCs from 50 patients were prospectively subdivided into a control group A (no manipulation of COC) and two study groups. In group B, surplus cumulus cells were cut off using syringes, and in the second study group COCs were incubated with a 1:11 dilution of hyaluronidase (final concentration 7 IU/l). Main outcome measures were fertilization rate, embryo development, as well as rates of implantation, pregnancy, and live birth.Results: Fertilization was higher in group C as compared to the untreated control group A (p<0.05). However, complete fertilization failure could not be avoided by any of the modified IVF approaches. Compaction on day 4 and blastocyst quality on day 5 were significantly improved in group C as compared to group B (but not to group A). Rates of implantation, pregnancy, and live birth were not affected by any of the methods.Conclusion: ICSI seems to be the only choice for avoiding the vast majority of fertilization failures after IVF. (J Turkish-German Gynecol Assoc 2011; 12: 135-9) Key words: Blastocyst, cumulus-oocyte complex, fertilization, hyaluronidase, IVF Received: 17 March, 2011 Accepted: 10 May, 2011 Amaç: Bu prospektif çalışma, kümülus-oosit-kompleksine (KOK) ilave işlemin (çok sayıdaki kümülus hücrelerinin kesilip ayrılması; hiyaluronidaz eklenmesi) tedavi sonuçlarını iyileştirmede yardımcı olup olmayacağını analiz etmek için yapıldı.

‘There is only one thing that is truly important in an IVF laboratory: everything’ Cairo Consensus Guidelines on IVF Culture Conditions

“…Trimming of COC is recommended if blood has infiltrated as this may affect embryo development (Ebner et al, 2008). An effect of reducing cumulus size in the absence of blood clots on development has not been shown Ebner et al, 2017.…”

Site specificity of blastocyst hatching significantly influences pregnancy outcomes in mice

“…31 In humans, if the ICM fails to release from the ZP when hatching from the abembryonic pole, this early interaction between the embryo and uterus is limited or blocked, 11 leading to a significantly decreased implantation rate. 32 In contrast, a significantly higher clinical pregnancy rate (72%) was observed from transferred human blastocysts hatching close to the ICM compared with those from the mural trophectoderm (51%). 33 An enlarged volume of the uterine cavity at the implantation site results in incomplete luminal closure, although complete luminal closure is necessary for normal decidualization, which is involved in hyperplasia and hypertrophy of stromal cells.…”

“…Hatched TE cells first contact the endometrium and engage in early inter‐cell dialog 31 . In humans, if the ICM fails to release from the ZP when hatching from the abembryonic pole, this early interaction between the embryo and uterus is limited or blocked, 11 leading to a significantly decreased implantation rate 32 . In contrast, a significantly higher clinical pregnancy rate (72%) was observed from transferred human blastocysts hatching close to the ICM compared with those from the mural trophectoderm (51%) 33 …”

The elusive MAESTRO gene: Its human reproductive tissue-specific expression pattern

“…Viable cell-counts for the purified GCs were performed using the semi-automated Countess instrument (ThermoFisher) according to the manufacturer’s instruction. CCs were collected by standard mechanical microdissection of oocytes by embryologists as previously described [ 16 , 17 ].…”