Askan Schultze-Mosgau

Three years of routine vitrification of human zygotes: is it still fair to advocate slow-rate freezing?

Cryopreservation of human oocytes and embryos is a necessary tool in assisted reproduction treatment that leads to an increased cumulative outcome while decreasing costs. Vitrification is a cryopreservation technique that leads to a glass-like solidification, with rapid cooling of cells or tissues. Nowadays vitrification is claimed to be the future of cryopreservation of human embryos due to improved survival rates and clinical outcomes. This study was conducted at a university clinic to assess the safety and efficiency of vitrification of human zygotes as a routine procedure. A total of 849 pronuclear-stage (PN) zygotes were vitrified between March 2004 and July 2006. During this period, 103 cycles of cryopreserved embryo transfer were completed. In total, 339 PN zygotes were thawed resulting in an 89% survival rate (302 PN zygotes). The mean number of embryos per transfer was 2.2. The pregnancy rate obtained was three times higher (36.9%) than that obtained with the slow-rate freezing method (10.2%) used previously in the same centre. In conclusion, vitrification of human zygotes at the pronuclear stage seems to be a successful and reliable method with favourable outcomes and can be recommended as a routine technique for cryopreservation of human embryos.

New developments in the use of peptide gonadotropin-releasing hormone antagonists versus agonists

Gonadotropin-releasing hormone (GnRH) stimulates the pituitary secretion of both luteinising hormone (LH) and follicle-stimulating hormone (FSH), and thus controls the hormonal and reproductive functions of the gonads. The blockade of the effects of GnRH may be sought for a variety of reasons; for example, to control premature LH surges and to reduce the cancellation rate with the aim of improving the pregnancy rate per treatment cycle or in the treatment of sex hormone-dependent disorders. Selective blockade of LH/FSH secretion and subsequent chemical castration have previously been achieved by desensitising the pituitary to continuously administered GnRH or by giving long-acting GnRH agonists. GnRH analogues are indicated for clinical situations in which the suppression of endogenous gonadotropins (precocious puberty, contraception and controlled ovarian hyperstimulation) or sexual steroids (endometriosis, prostate hyperplasia, cancer and uterine fibroids) is desired. The immediate suppression of the pituitary that is achieved by GnRH antagonists without an initial stimulatory effect is the main advantage of these compounds over the agonists. GnRH antagonists have been developed for clinical use with acceptable pharmacokinetic, safety and commercial profiles. In assisted reproduction, these compounds seem to be as effective as established therapy, but with shorter treatment times, less use of gonadotropic hormones, improved patient acceptance, and fewer follicles and oocytes. All of the current indications for GnRH agonist desensitisation may prove to be indications for a GnRH antagonist, including endometriosis, leiomyoma and breast cancer in women, benign prostatic hypertrophy and prostatic carcinoma in men, and central precocious puberty in children. However, the best clinical evidence has been in assisted reproduction and prostate cancer.

GnRH agonists and antagonists in assisted reproduction: pregnancy rate

Although gonadotrophin-releasing hormone (GnRH) antagonists offer many advantages when used in ovarian stimulation, their popularity is lower than expected. GnRH protocols are suspected to yield lower pregnancy rates compared with the long agonist protocol. In the current study, subgroup analyses from the German IVF registry (DIR) were performed to evaluate the hypothesis that GnRH antagonists are often used as second-line medication in patients with difficult medical conditions, and thus pregnancy rates may be biased. Consequently, pregnancy rates in the first six stimulation cycles (low rank cycles) were more favourable in the group treated according to the long protocol, while in the patient group requiring more stimulation cycles (high rank cycles; 7, 9 and 10), numerically higher pregnancy rates were achieved with GnRH antagonist protocols. On the other hand, in a patient collective with equal demographic and clinical features (<35 years, tubal infertility), the long and the GnRH antagonist protocols resulted in similar pregnancy rates, supporting the hypothesis that both stimulation protocols lead to equal results.

Factors affecting outcome after ICSI with spermatozoa retrieved from cryopreserved testicular tissue in non-obstructive azoospermia

There is a lack of data regarding variables affecting the treatment outcome for non-obstructive azoospermia when spermatozoa from cryopreserved testicular specimens are utilized for ICSI. The objective of the present retrospective analysis was to investigate the effect of various parameters on treatment outcome in such cases. One hundred and sixty-five couples with non-obstructive azoospermic males undergoing a total of 297 cycles were included. In all cases the testicular tissue retrieved by multiple open-biopsy testicular sperm extraction was stored in liquid nitrogen and, after thawing, only mature spermatozoa were used for ICSI. When no motile spermatozoa were recovered, immotile spermatozoa were used. In 159 cycles, motile spermatozoa were utilized for ICSI, while in 138 cycles immotile spermatozoa were utilized. Higher normal fertilization rate (60.4 +/- 3.1 versus 51.3 +/- 1.6%, P < 0.05), number of embryos transferred (2.8 +/- 0.06 versus 2.6 +/- 0.04, P < 0.05), modified cumulative embryo score (31.2 +/- 1.6 versus 23.9 +/- 0.8, P < 0.001), and proportion of motile spermatozoa injected (67.8 versus 49.8%, P < 0.05) were observed in cycles that resulted in clinical pregnancies. Binary logistic regression analysis showed that sperm motility (odds ratio 2.06, 95% CI 1.1-3.9, P < 0.05), but not womans age, number of treatment cycle, type of GnRH-analogue used for pituitary suppression, number of oocytes retrieved or number of embryos transferred was a significant determinant of the likelihood of clinical pregnancy. In conclusion, sperm motility after freeze/thawing of testicular tissue is the major determinant of the success of ICSI in non-obstructive azoospermia.

First pregnancy and life after preimplantation genetic diagnosis by polar body analysis for mucopolysaccharidosis type I

Preimplantation genetic diagnosis (PGD) may help couples at risk to avoid pregnancies with known genetic diseases. In Germany, the only option to perform PGD is the analysis of polar bodies (PB). Mucopolysaccharidosis type I (MPS I) is an autosomal recessive lysosomal storage disorder. Q70X is one of the frequent diseases causing mutations of alpha-L-iduronidase (IDUA), leading to a severe phenotype with mental retardation and various somatic abnormalities, and making a request for PGD is understandable. Using five polymorphic DNA markers from the vicinity of IDUA, PGD on first PB was performed for a consanguineous couple, both heterozygotes of the Q70X mutation of IDUA. Sixteen first PB were obtained by laser assisted hatching of the zona pellucida. Genotyping led to the conclusion that 3/16 oocytes carried wild-type IDUA alleles. Only one of these oocytes showed pronucleus formation after intracytoplasmic sperm injection and was transferred on day 2 after oocyte retrieval. A singleton pregnancy was established. Prenatal diagnosis showed a fetus heterozygous for Q70X. For MPS I, PB analysis is a feasible way to perform PGD and it may be an acceptable alternative for couples with moral objections to embryo selection, or for countries in which genetic testing of the embryo is prohibited.

Comet assay of cumulus cells and spermatozoa DNA status, and the relationship to oocyte fertilization and embryo quality following ICSI.

It has been postulated that apoptosis may affect cumulus cell and sperm DNA integrity, and therefore influence the outcome of assisted reproductive techniques. This study investigates apoptotic levels in both cumulus cells and spermatozoa, and their relationship with fertilization and embryo quality after intracytoplasmic sperm injection (ICSI). The neutral comet assay was performed on cumulus cells and semen samples from 55 couples with male factor infertility undergoing ICSI treatment. Cells were fixed in agarose on comet assay slides, lysed in a neutral buffer and submitted to electrophoresis. The cells were stained with SYBR green fluorescent dye, which binds to double-stranded DNA and upon excitation emits light. Analysis showed that there was no correlation between apoptosis levels and the outcome of ICSI (fertilization and embryo quality).

Cumulative pregnancy rate after ICSI with cryopreserved testicular tissue in non-obstructive azoospermia

The aim of the present study was to describe a simplified and inexpensive method of testicular tissue freezing, to assess the cumulative clinical pregnancy rate (CPR) by this technique, and to provide useful information for counselling couples with non-obstructive azoospermia. One hundred and sixty-five couples with non-obstructive azoospermic males pursuing assisted conception, from December 1995 to December 2002, were included. In all cases, the testicular tissue retrieved by open multiple-biopsy (both sides, by testicular sperm extraction) was frozen using a simple liquid nitrogen vapour freezing technique and was stored in liquid nitrogen thereafter. Only mature spermatozoa were used for intracytoplasmic sperm injection (ICSI) after thawing. Expected CPR were calculated using the Kaplan-Meier survival analysis. A total of 281 cycles were performed resulting in 53 clinical pregnancies. Crude and expected CPR (95% confidence intervals) after three cycles were 32.1 (25.7-40.1) and 55.7% (37.0-74.4) respectively. In conclusion, this simplified method for freezing testicular tissue resulted in a satisfactory outcome after ICSI in cases of non-obstructive azoospermia.

Cetrorelix in the treatment of female infertility and endometriosis

The use of cetrorelix within ovarian-stimulation protocols demonstrates several advantages compared with gonadotropin-releasing hormone (GnRH) agonist-containing protocols, which include, for example, significantly less time for analogue treatment and a reduction in the amount of gonadotropins needed. Furthermore, fewer side effects can be expected. There is no difference regarding endometrium quality and hormone profiles, and the results of assisted reproduction cycles are comparable. Cetrorelix also seems to be useful in the treatment of endometriosis which, in most cases, is an estrogen-dependent disease. Furthermore, fewer side effects occur with this agent (e.g., postmenopausal symptoms) and no estradiol add-back is needed. In the future, new nonpeptic GnRH antagonists are expected to be available for oral administration. Although they are still under investigation, these agents have the potential to improve patients’ comfort and compliance.

Cumulative live birth rates after GnRH-agonist triggering of final oocyte maturation in patients at risk of OHSS: A prospective, clinical cohort study

OBJECTIVES To prospectively study the incidence of OHSS, live birth likelihood and neonatal outcome after GnRH-agonist triggering of final oocyte maturation and vitrification of all pronucleate (2PN) oocytes for later frozen-thawed embryo transfer (FRET) in an OHSS-risk population. STUDY DESIGN Prospective, clinical cohort study (12/2004-5/2009). Forty patients undergoing ovarian stimulation in a GnRH-antagonist protocol and at risk of developing severe OHSS underwent triggering with 0.2mg triptorelin and elective vitrification of all 2PN-oocytes for later frozen-thawed embryo transfer. RESULTS The incidence of OHSS was 0% (0/40; 95% confidence interval: 0.0-6.4%). Thirty-nine patients underwent 87 FRETs (mean number of FRETs per patient: 2.2+/-1.6; range: 1-7). The cumulative live birth rate per patient was 35.0% (14/40; 95% confidence interval: 23.9-48.0%). Mean time-to-conception resulting in live birth after agonist triggering was 24.2 (+/-17.1; range: 9-67) weeks. Nine healthy singletons and five twins were born. CONCLUSIONS A treatment algorithm combining agonist trigger with vitrification of all 2PN-oocytes is feasible and safe, and provides patients with a good cumulative chance of live birth.

Polar Body Diagnosis for Hemophilia A Using Multiplex PCR for Linked Polymorphic Markers

Preimplantation genetic diagnosis (PGD) is usually performed on blastomeres. In Germany, the only possibility to perform PGD is by analysis of polar bodies. We performed PGD using polar bodies in a woman who is a carrier of hemophilia A. Multiplex PCR followed by nested fluorescent PCR for five linked polymorphic markers was established. From 11 analyzed polar bodies, only 1 showed alleles linked to the mutation. The corresponding oocyte was transferred and no pregnancy was established. As seen in other investigations, the rate of heterozygous first polar bodies is surprisingly high.