D4Z4 Hypomethylation in Human Germ Cells.

Expression of the double homeobox 4 (DUX4) transcription factor is highly regulated in early embryogenesis and is subsequently epigenetically silenced. Ectopic expression of DUX4 due to hypomethylation of the D4Z4 repeat array on permissive chromosome 4q35 alleles is associated with facioscapulohumeral muscular dystrophy (FSHD). In peripheral blood samples from 188 healthy individuals, D4Z4 methylation was highly variable, ranging from 19% to 76%, and was not affected by age. In 48 FSHD2 patients, D4Z4 methylation varied from 3% to 30%. Given that DUX4 is one of the earliest transcribed genes after fertilization, the D4Z4 array is expected to be unmethylated in mature germ cells. Deep bisulfite sequencing of 188 mainly normozoospermic sperm samples revealed an average methylation of 2.5% (range 0.3-22%). Overall, the vast majority (78%) of individual sperm cells displayed no methylation at all. In contrast, only 19 (17.5%) of 109 individual germinal vesicle (GV) oocytes displayed D4Z4 methylation <2.5%. However, it is not unexpected that immature GV oocytes which are not usable for assisted reproduction are endowed with D4Z4 (up to 74%) hypermethylation and/or abnormal (PEG3 and GTL2) imprints. Although not significant, it is interesting to note that the pregnancy rate after assisted reproduction was higher for donors of sperm samples and oocytes with <2.5% methylation.

Effects of paternal and chronological age on BEGAIN methylation and its possible role in autism.

Children from old fathers carry an increased risk for autism spectrum (ASD) and other neurodevelopmental disorders, which may at least partially be mediated by paternal age effects on the sperm epigenome. The brain enriched guanylate kinase associated (BEGAIN) protein is involved in protein-protein interactions at and transmission across synapses. Since several epigenome-wide methylation screens reported a paternal age effect on sperm BEGAIN methylation, here we confirmed a significant negative correlation between BEGAIN promoter methylation and paternal age, using more sensitive bisulfite pyrosequencing and a larger number of sperm samples. Paternal age-associated BEGAIN hypomethylation was also observed in fetal cord blood (FCB) of male but not of female offspring. There was no comparable maternal age effect on FCB methylation. In addition, we found a significant negative correlation between BEGAIN methylation and chronological age (ranging from 1 to 70 years) in peripheral blood samples of male but not of female donors. BEGAIN hypomethylation was more pronounced in male children, adolescents and adults suffering from ASD compared to controls. Both genetic variation (CC genotype of SNP rs7141087) and epigenetic factors may contribute to BEGAIN promoter hypomethylation. The age- and sex-specific BEGAIN methylation trajectories in the male germ line and somatic tissues, in particular the brain, support a role of this gene in ASD development.

Age-related methylation changes in the human sperm epigenome.

Advanced paternal age is associated with increased risks for reproductive and offspring medical problems. Accumulating evidence suggests age-related changes in the sperm epigenome as one underlying mechanism. Using reduced representation bisulfite sequencing on 73 sperm samples of males attending a fertility center, we identified 1,162 (74%) regions which were significantly (FDR-adjusted) hypomethylated and 403 regions (26%) being hypermethylated with age. There were no significant correlations with paternal BMI, semen quality, or ART outcome. The majority (1,152 of 1,565; 74%) of age-related differentially methylated regions (ageDMRs) were located within genic regions, including 1,002 genes with symbols. Hypomethylated ageDMRs were closer to transcription start sites than hypermethylated DMRs, half of which reside in gene-distal regions. In this and conceptually related genome-wide studies, so far 2,355 genes have been reported with significant sperm ageDMRs, however most (90%) of them in only one study. The 241 genes which have been replicated at least once showed significant functional enrichments in 41 biological processes associated with development and the nervous system and in 10 cellular components associated with synapses and neurons. This supports the hypothesis that paternal age effects on the sperm methylome affect offspring behaviour and neurodevelopment. It is interesting to note that sperm ageDMRs were not randomly distributed throughout the human genome; chromosome 19 showed a highly significant twofold enrichment with sperm ageDMRs. Although the high gene density and CpG content have been conserved, the orthologous marmoset chromosome 22 did not appear to exhibit an increased regulatory potential by age-related DNA methylation changes.

Species-Specific Paternal Age Effects and Sperm Methylation Levels of Developmentally Important Genes.

A growing number of sperm methylome analyses have identified genomic loci that are susceptible to paternal age effects in a variety of mammalian species, including human, bovine, and mouse. However, there is little overlap between different data sets. Here, we studied whether or not paternal age effects on the sperm epigenome have been conserved in mammalian evolution and compared methylation patterns of orthologous regulatory regions (mainly gene promoters) containing both conserved and non-conserved CpG sites in 94 human, 36 bovine, and 94 mouse sperm samples, using bisulfite pyrosequencing. We discovered three (NFKB2, RASGEF1C, and RPL6) age-related differentially methylated regions (ageDMRs) in humans, four (CHD7, HDAC11, PAK1, and PTK2B) in bovines, and three (Def6, Nrxn2, and Tbx19) in mice. Remarkably, the identified sperm ageDMRs were all species-specific. Most ageDMRs were in genomic regions with medium methylation levels and large methylation variation. Orthologous regions in species not showing this age effect were either hypermethylated (>80%) or hypomethylated (<20%). In humans and mice, ageDMRs lost methylation, whereas bovine ageDMRs gained methylation with age. Our results are in line with the hypothesis that sperm ageDMRs are in regions under epigenomic evolution and may be part of an epigenetic mechanism(s) for lineage-specific environmental adaptations and provide a solid basis for studies on downstream effects in the genes analyzed here.

Increasing methylation of sperm rDNA and other repetitive elements in the aging male mammalian germline.

In somatic cells/tissues, methylation of ribosomal DNA (rDNA) increases with age and age-related pathologies, which has a direct impact on the regulation of nucleolar activity and cellular metabolism. Here, we used bisulfite pyrosequencing and show that methylation of the rDNA transcription unit including upstream control element (UCE), core promoter, 18S rDNA, and 28S rDNA in human sperm also significantly increases with donor's age. This positive correlation between sperm rDNA methylation and biological age is evolutionarily conserved among mammals with widely different life spans such as humans, marmoset, bovine, and mouse. Similar to the tandemly repeated rDNA, methylation of human α-satellite and interspersed LINE1 repeats, marmoset α-satellite, bovine alpha- and testis satellite I, mouse minor and major satellite, and LINE1-T repeats increases in the aging male germline, probably related to their sperm histone packaging. Deep bisulfite sequencing of single rDNA molecules in human sperm revealed that methylation does not only depend on donor's age, but also depend on the region and sequence context (A vs. G alleles). Both average rDNA methylation of all analyzed DNA molecules and the number of fully (>50%) methylated alleles, which are thought to be epigenetically silenced, increase with donor's age. All analyzed CpGs in the sperm rDNA transcription unit show comparable age-related methylation changes. Unlike other epigenetic aging markers, the rDNA clock appears to operate in similar ways in germline and soma in different mammalian species. We propose that sperm rDNA methylation, directly or indirectly, influences nucleolar formation and developmental potential in the early embryo.

Male obesity effects on sperm and next-generation cord blood DNA methylation.

The prevalence of metabolic disorders, in particular obesity has dramatically increased worldwide. Genetic variants explain only a minor part of the obesity epidemic induced by physical inactivity and over-nutrition. Epidemiological studies in humans and animal models indicate that epigenetic changes associated with adverse parental and/or intrauterine factors may contribute to the missing heritability of metabolic disorders. Possible adverse paternal effects are likely transmitted by sperm to the next-generation. To investigate this hypothesis, we have systematically analyzed the effects of male body mass index (BMI) on sperm epigenome and its association with next-generation fetal cord blood (FCB) DNA methylation. Methylation levels of maternally imprinted (PEG1, PEG4, PEG5, and PEG10), paternally imprinted (H19-IG DMR, IGF2-DMR0, and MEG3-IG DMR) regions, and obesity-related non-imprinted HIF3A gene were quantified by bisulphite pyrosequencing in sperm samples of 294 human donors undergoing in vitro fertilization or intracytoplasmic sperm injection, and in 113 FCBs of the resulting offspring. Multivariable regression analyses revealed that MEG3 intergenic differentially methylated region (IG DMR) showed positive correlation between sperm methylation and donor's BMI. A gender-specific correlation between paternal BMI and FCB methylation was observed for MEG3-IG DMR, HIF3A, and IGF2-DMR0. The former two genes displayed same directional nominal association (as sperm) between paternal BMI and FCB methylation in male offspring. Hypomethylation of IGF2-DMR0 with increased paternal BMI was observed in FCBs from female offsprings. Our results suggest that male obesity is nominally associated with modification of sperm DNA methylome in humans, which may affect the epigenome of the next-generation. Nevertheless, it is important to note that none of the associated p-values survived multiple testing adjustments. Future work should test the effect of associated methylation aberrations in the offspring as DNA methylation was shown to control expression and/or imprint establishment across the studied genes.

Fertility After Ovarian Cystectomy: How Does Surgery Affect IVF/ICSI Outcomes?

Introduction For patients considering undergoing assisted reproductive techniques (ART), many concerns arise when persistent ovarian cysts are found. This large study aimed to determine how ovarian cyst removal affects success rates of IVF/ICSI therapies. Methods 550 patients who underwent an IVF/ICSI treatment between 2002 and 2011 with a persistent ovarian cyst ≤ 5 cm before treatment were analyzed retrospectively. 328 patients' preference was to undergo a laparoscopic cystectomy and 222 patients opted for a conservative management. Control subjects included 13 552 patients undergoing IVF/ICSI at the same period of time without an ovarian cyst. Results After adjusting for age, patients with ovarian cysts without surgery needed a significant higher stimulation dose than the control group (2576.4 vs. 2207.5 IU, p < 0.001). However, on average, they had 1.13 (- 0.25 - 2.01) higher oocyte number retrieved compared to the operated patients (9.0 ± 5.5 vs. 8.2 ± 5.0) (p = 0.012). Patients after surgical cyst removal had a significant lower number of oocytes retrieved (MNOR) in comparison to the control group (8.2 ± 5.0 vs. 9.5 ± 5.4) (p = 0.00). Compared to controls, operated patients had similar clinical pregnancy rate (CPR) (34.2 vs. 33.5%) OR 1.031 (95% CI 0.817 - 1.302) (p = 0.815). Compared to controls, patients without surgery showed significant lower pregnancy rate (34.2 vs. 25,7%) OR 1.428 (95% CI 1.054 - 1.936) (p = 0.002) and lower live birth rate (LBR) (21.9 vs. 13.5%) OR 1.685 (95% CI 1.143 - 2.485) (p = 0.008). Conclusions Ovarian cystectomy did not negatively impact the pregnancy rate or the live birth rate compared to controls.

Allele-specific methylation of imprinted genes in fetal cord blood is influenced by cis-acting genetic variants and parental factors.

AIM: To examine the effects of genetic variation, parental age and BMI on parental allele-specific methylation of imprinted genes in fetal cord blood samples. METHODOLOGY: We have developed SNP genotyping and deep bisulphite sequencing assays for six imprinted genes to determine parental allele-specific methylation patterns in diploid somatic tissues. RESULTS: Multivariate linear regression analyses revealed a negative correlation of paternal age with paternal MEG3 allele methylation in fetal cord blood. Methylation of the maternal PEG3 allele showed a positive correlation with maternal age. Paternal BMI was positively correlated with paternal MEST allele methylation. In addition to parental origin, allele-specific methylation of most imprinted genes was largely dependent on the underlying SNP haplotype. CONCLUSION: Our study supports the idea that parental factors can have an impact, although of small effect size, on the epigenome of the next generation, providing an additional layer of complexity to phenotypic diversity.

Hypermethylation of the non-imprinted maternal MEG3 and paternal MEST alleles is highly variable among normal individuals.

Imprinted genes show parent-specific activity (functional haploidy), which makes them particularly vulnerable to epigenetic dysregulation. Here we studied the methylation profiles of oppositely imprinted genes at single DNA molecule resolution by two independent parental allele-specific deep bisulfite sequencing (DBS) techniques. Using Roche (GSJunior) next generation sequencing technology, we analyzed the maternally imprinted MEST promoter and the paternally imprinted MEG3 intergenic (IG) differentially methylated region (DMR) in fetal cord blood, adult blood, and visceral adipose tissue. Epimutations were defined as paternal or maternal alleles with >50% aberrantly (de)methylated CpG sites, showing the wrong methylation imprint. The epimutation rates (range 2-66%) of the paternal MEST and the maternal MEG3 IG DMR allele, which should be completely unmethylated, were significantly higher than those (0-15%) of the maternal MEST and paternal MEG3 alleles, which are expected to be fully methylated. This hypermethylation of the non-imprinted allele (HNA) was independent of parental origin. Very low epimutation rates in sperm suggest that HNA occurred after fertilization. DBS with Illumina (MiSeq) technology confirmed HNA for the MEST promoter and the MEG3 IG DMR, and to a lesser extent, for the paternally imprinted secondary MEG3 promoter and the maternally imprinted PEG3 promoter. HNA leads to biallelic methylation of imprinted genes in a considerable proportion of normal body cells (somatic mosaicism) and is highly variable between individuals. We propose that during development and differentiation maintenance of differential methylation at most imprinting control regions may become to some extent redundant. The accumulation of stochastic and environmentally-induced methylation errors on the non-imprinted allele may increase epigenetic diversity between cells and individuals.

DNA methylation signatures in cord blood of ICSI children.

STUDY QUESTION: Does ICSI induce specific DNA methylation changes in the resulting offspring? SUMMARY ANSWER: Although several thousand analyzed CpG sites (throughout the genome) displayed significant between-group methylation differences, both ICSI and spontaneously conceived children varied within the normal range of methylation variation. WHAT IS KNOWN ALREADY: Children conceived by ART have increased risks for medical problems at birth and to the extent of present knowledge also in later life (i.e. impaired metabolic and cardiovascular functions). One plausible mechanism mediating these ART effects are epigenetic changes originating in the germ cells and/or early embryos and persisting during further development. STUDY DESIGN, SIZE, DURATION: We compared the cord blood methylomes and candidate gene methylation patterns of newborns conceived through ICSI or spontaneously. PARTICIPANTS/MATERIALS, SETTING, METHODS: Umbilical cord bloods were obtained from healthy newborn singletons conceived spontaneously (53 samples), through ICSI (89) or IVF (34). Bisulfite-converted DNA samples of 48 ICSI and 46 control pregnancies were used for genome-wide analyses with Illumina's 450K methylation arrays. Candidate genes from the methylation screen were analyzed in all three groups by bisulfite pyrosequencing. MAIN RESULTS AND THE ROLE OF CHANCE: Altogether, 4730 (0.11%) of 428 227 analyzed CpG sites exhibited significant between-group methylation differences, but all with small (ß < 10%) or very small (ß < 1%) effect size. ICSI children showed a significantly decreased DNA methylation age at birth, lagging approximately half a week behind the controls. ART-susceptible CpGs were enriched in CpG islands with low methylation values (0-20%) and in imprinting control regions (ICRs). Eighteen promoter regions (six in microRNA and SNORD RNA genes), four CpG islands (three in genes including one long non-coding RNA), and two ICRs contained multiple significant sites. Three differentially methylated regions were studied in more detail by bisulfite pyrosequencing. ATG4C and SNORD114-9 could be validated in an independent ICSI group, following adjustment for maternal age and other confounding factors. ATG4C was also significant in the IVF group. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: The observed epigenetic effects are small and there are numerous potential confounding factors such as parental age and infertility. Although our study meets current standards for epigenetic screens, sample size is still two orders of magnitude below that of genome-wide association studies. WIDER IMPLICATIONS OF THE FINDINGS: Our study suggests an impact of ICSI on the offspring's epigenome(s), which may contribute to phenotypic variation and disease susceptibility in ART children. Epigenetic regulation of gene expression by different classes of non-coding RNAs may be a key mechanism for developmental programming through ART. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by a research grant (no. 692185) from the European Union (ERA of ART). There are no competing interests.

Paternal age effects on sperm FOXK1 and KCNA7 methylation and transmission into the next generation.

Children of older fathers carry an increased risk for developing autism and other disorders. To elucidate the underlying mechanisms, we investigated the correlation of sperm DNA methylation with paternal age and its impact on the epigenome of the offspring. Methylation levels of nine candidate genes and LINE-1 repeats were quantified by bisulfite pyrosequencing in sperm DNA of 162 donors and 191 cord blood samples of resulting children (conceived by IVF/ICSI with the same sperm samples). Four genes showed a significant negative correlation between sperm methylation and paternal age. For FOXK1 and KCNA7, the age effect on the sperm epigenome was replicated in an independent cohort of 188 sperm samples. For FOXK1, paternal age also significantly correlated with foetal cord blood (FCB) methylation. Deep bisulfite sequencing and allele-specific pyrosequencing allowed us to distinguish between maternal and paternal alleles in FCB samples with an informative SNP. FCB methylation of the paternal FOXK1 allele was negatively correlated with paternal age, whereas maternal allele was unaffected by maternal age. Since FOXK1 duplication has been associated with autism, we studied blood FOXK1 methylation in 74 children with autism and 41 age-matched controls. The FOXK1 promoter showed a trend for accelerated demethylation in the autism group. Dual luciferase reporter assay revealed that FOXK1 methylation influences gene expression. Collectively, our study demonstrates that age-related DNA methylation changes in sperm can be transmitted to the next generation and may contribute to the increased disease risk in offspring of older fathers.

Methylation analysis of histone H4K12ac-associated promoters in sperm of healthy donors and subfertile patients.

BACKGROUND: Histone to protamine exchange and the hyperacetylation of the remaining histones are hallmarks of spermiogenesis. Acetylation of histone H4 at lysine 12 (H4K12ac) was observed prior to full decondensation of sperm chromatin after fertilization suggesting an important role for the regulation of gene expression in early embryogenesis. Similarly, DNA methylation may contribute to gene silencing of several developmentally important genes. Following the identification of H4K12ac-binding promoters in sperm of fertile and subfertile patients, we aimed to investigate whether the depletion of histone-binding is associated with aberrant DNA methylation in sperm of subfertile men. Furthermore, we monitored the transmission of H4K12ac, 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) from the paternal chromatin to the embryo applying mouse in vitro fertilization and immunofluorescence. RESULTS: Chromatin immunoprecipitation (ChIP) with anti-H4K12ac antibody was performed with chromatin isolated from spermatozoa of subfertile patients with impaired sperm chromatin condensation assessed by aniline blue staining. Fertile donors were used as control. DNA methylation analysis of selected H4K12ac-interacting promoters in spermatozoa was performed by pyrosequencing. Depletion of binding sites for H4K12ac was observed within the following developmentally important promoters: AFF4, EP300, LRP5, RUVBL1, USP9X, NCOA6, NSD1, and POU2F1. We found 5% to 10% hypomethylation within CpG islands of selected promoters in the sperm of fertile donors, and it was not significantly altered in the subfertile group. Our results demonstrate that the H4K12ac depletion in selected developmentally important promoters of subfertile patients was not accompanied by a change of DNA methylation. Using a murine model, immunofluorescence revealed that H4K12ac co-localize with 5mC in the sperm nucleus. During fertilization, when the pronuclei are formed, the paternal pronucleus exhibits a strong acetylation signal on H4K12, while in the maternal pronucleus, there is a permanent increase of H4K12ac until pronuclei fusion. Simultaneously, there is an increase of the 5hmC signal and a decrease of the 5mC signal. CONCLUSIONS: We suggest that aberrant histone acetylation within developmentally important gene promoters in subfertile men, but not DNA methylation, may reflect insufficient sperm chromatin compaction affecting the transfer of epigenetic marks to the oocyte.

The effect of ovarian stimulation on the outcome of intrauterine insemination.

PURPOSE: Although intrauterine insemination is one of the oldest techniques in reproductive medicine, its significance is still controversially discussed. Many factors have been reported as influencing pregnancy rates after IUI. The aim of this retrospective analysis is to evaluate the success rate of repeated inseminations depending on the type of ovarian stimulation. METHODS: Patients who underwent intrauterine insemination in Wiesbaden Kinderwunschzentrum between 1998 and 2010, not older than 45 years of age, with male subfertility were included in this study. On the whole, 5,346 inseminations on 2,180 patients were analyzed retrospectively. RESULTS: Females' mean age was 34.1, ranging from 19-45 years. In 433 cycles an insemination was performed during a natural cycle. 4,020 cycles were stimulated with recombinant FSH, 596 cycles with clomiphene, 194 with urinary FSH, 103 with HMG. The pregnancy rates range from 7.4% in the clomiphene group to 14.4% in the urinary FSH group. Clomiphene stimulation seems to offer the significantly lowest pregnancy rate (p = 0.03). The other types of stimulation do not differ significantly from each other concerning the pregnancy rate. Patients under 39 years of age do not profit from any ovarian stimulation. In 40 and more years of old patients, pregnancy rates are higher, if any stimulation was performed. CONCLUSION: To sum up, clomiphene stimulation showed to offer significantly lower pregnancy rates in comparison to the natural cycle, FSH stimulation and HMG stimulation in IUI treatment. While women younger than 40 seem not to profit from any ovarian stimulation, women over 40 do profit.

Epigenetic heterogeneity of developmentally important genes in human sperm: implications for assisted reproduction outcome.

The molecular basis of male infertility is poorly understood, the majority of cases remaining unsolved. The association of aberrant sperm DNA methylation patterns and compromised semen parameters suggests that disturbances in male germline epigenetic reprogramming contribute to this problem. So far there are only few data on the epigenetic heterogeneity of sperm within a given sample and how to select the best sperm for successful infertility treatment. Limiting dilution bisulfite sequencing of small pools of sperm from fertile donors did not reveal significant differences in the occurrence of abnormal methylation imprints between sperm with and without morphological abnormalities. Intracytoplasmic morphologically selected sperm injection was not associated with an improved epigenetic quality, compared to standard intracytoplasmatic sperm injection. Deep bisulfite sequencing (DBS) of 2 imprinted and 2 pluripotency genes in sperm from men attending a fertility center showed that in both samples with normozoospermia and oligoasthenoteratozoospermia (OAT) the vast majority of sperm alleles was normally (de)methylated and the percentage of epimutations (allele methylation errors) was generally low (<1%). However, DBS allowed one to identify and quantify these rare epimutations with high accuracy. Sperm samples not leading to a pregnancy, in particular in the OAT group, had significantly more epimutations in the paternally methylated GTL2 gene than samples leading to a live birth. All 13 normozoospermic and 13 OAT samples leading to a child had <1% GTL2 epimutations, whereas one (7%) of 14 normozoospermic and 7 (50%) of 14 OAT samples without pregnancy displayed 1-14% GTL2 epimutations.

The sperm protamine mRNA ratio as a clinical parameter to estimate the fertilizing potential of men taking part in an ART programme.

STUDY QUESTION: Could the protamine-1 to protamine-2 mRNA ratio serve as a biomarker to estimate the fertilizing capacity of sperm from men taking part in an IVF/ICSI programme? SUMMARY ANSWER: The protamine mRNA ratio clearly discriminates between fertile and subfertile men and sperm with a normal protamine mRNA ratio exhibit a higher fertilizing capacity in IVF/ICSI. WHAT IS KNOWN ALREADY: Aberrant sperm protamine ratios are associated with male factor infertility and mRNA ratio is comparable with protein ratio (due to transcriptional stop in elongating spermatids). STUDY DESIGN, SIZE, DURATION: The study population was drawn from subfertile men, whose female partners participated in IVF or ICSI programmes between September 2010 and February 2012. Normozoospermic healthy volunteers served as controls. Sperm cells were lysed, mRNA extracted, reverse transcribed and subjected to real-time quantitative PCR using specific primer pairs for protamine-1 and protamine-2. Relative protamine-1 and protamine-2 mRNA levels were analysed with the Mann-Whitney U-test (two-tailed). PARTICIPANTS/MATERIALS, SETTING, METHODS: Quantitative RT-PCR for protamines 1 and 2 has been performed in ejaculates from 32 normozoospermic volunteers (control, University Clinic Giessen, Germany) and 306 patients, whose female partners took part in an IVF (n = 76; University Clinic Hamburg, Germany and Shanghai Jiaotong University, China) or an ICSI (n = 230; University Clinic Munich, Germany and Kinderwunschzentrum Wiesbaden, Germany) programme. MAIN RESULTS AND THE ROLE OF CHANCE: The sperm protamine mRNA ratio in normozoospermic men (0.98 ± 0.3) differed significantly from that of ICSI patients (Munich 0.81 ± 0.1; Wiesbaden 0.78 ± 0.2; P < 0.001), while processed samples obtained from IVF patients revealed a normal protamine mRNA ratio (Hamburg 1.0 ± 0.07; Shanghai 1.0 ± 0.54). Normal protamine mRNA ratios were associated with a significantly higher total motile sperm count and a significantly higher percentage of progressively motile sperm. Sperm with a normal protamine mRNA ratio revealed a higher fertilization capacity (fc) in both IVF (53.6% of patients with fc > 80%; P = 0.017) and ICSI (65.1% of patients with fc > 70%; P = 0.028). LIMITATIONS, REASONS FOR CAUTION: The protamine mRNA ratio in an individual sperm cell used for ICSI may be different from the overall value obtained from a semen aliquot. WIDER IMPLICATIONS OF THE FINDINGS: Data are in line with current literature and suggest the protamine mRNA ratio as a diagnostic marker to estimate the fertilizing capacity of sperm. STUDY FUNDING: The German Research Foundation (DFG) to K.S., W.W. and A.P. (STE 892/9-2), as well as to A.S. and H.C.O. (SP721/1-3). COMPETING INTEREST(S): None.

Antiphospholipid syndrome and pre-eclampsia.

Antiphospholipid syndrome (APS) is defined as an autoimmune disorder characterized by recurrent thrombosis or obstetrical morbidity. These features are linked to the presence in blood of autoantibodies against negatively charged phospholipids or phospholipid-binding proteins. Obstetric morbidity includes recurrent abortion (early and late) and severe pre-eclampsia (P-EC)/hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome, and/or severe placental insufficiency. Criteria that define the major clinical and laboratory events were published in revised forms in the Sydney recommendations in 2006. We analyzed the blood of patients with severe P-EC according to the subgroups based on the 2006 revised criteria definition and compared these results with women after uncomplicated pregnancy and delivery. We found 20% elevated antiphospholipid antibodies (APAs) in women with severe P-EC (group I, 7.5%; group IIa, 5.0%; group IIb, 5.0%; group IIc, 2.5%). The increased APAs were observed only in women with severe P-EC (odds ratio: 2.45; 95% confidence interval, 1.01 to 4.3) and not in patients with severe P-EC at >34 weeks of gestation. According to our retrospective observation, we recommend the determination of anticardiolipin antibodies, lupus anticoagulant, and ß-2 glycoprotein-1 antibodies in patients with severe P-EC at <34 weeks of gestation.

Spatial, temporal and interindividual epigenetic variation of functionally important DNA methylation patterns.

DNA methylation is an epigenetic modification that plays an important role in gene regulation. It can be influenced by stochastic events, environmental factors and developmental programs. However, little is known about the natural variation of gene-specific methylation patterns. In this study, we performed quantitative methylation analyses of six differentially methylated imprinted genes (H19, MEG3, LIT1, NESP55, PEG3 and SNRPN), one hypermethylated pluripotency gene (OCT4) and one hypomethylated tumor suppressor gene (APC) in chorionic villus, fetal and adult cortex, and adult blood samples. Both average methylation level and range of methylation variation depended on the gene locus, tissue type and/or developmental stage. We found considerable variability of functionally important methylation patterns among unrelated healthy individuals and a trend toward more similar methylation levels in monozygotic twins than in dizygotic twins. Imprinted genes showed relatively little methylation changes associated with aging in individuals who are >25 years. The relative differences in methylation among neighboring CpGs in the generally hypomethylated APC promoter may not only reflect stochastic fluctuations but also depend on the tissue type. Our results are consistent with the view that most methylation variation may arise after fertilization, leading to epigenetic mosaicism.

CD3-CD56+CD16+ natural killer cells and improvement of pregnancy outcome in IVF/ICSI failure after additional IVIG-treatment.

PROBLEM: The purpose of this retrospective, observational study was to investigate whether additional treatment with intravenous immunoglobulin (IVIG) increased the rate of successful pregnancies after repeated implantation failure (RIF). The retrospective data were compared with data of patients without IVIG-therapy from the meta-analysis of Clark et al. METHOD OF STUDY: A total of 188 women with 226 treatment cycles between 2007 and 2009 were evaluated for IVIG therapy. The percentage of NK cells was measured two times before a new embryo transfer (only women with NK cell percentages >12% were included) and after embryo transfer at a positive pregnancy test. RESULTS: In comparison with the meta-analysis of Clark et al., we observed a pregnancy rate of 50.5%, an implantation rate of 21% and a miscarriage rate of 16.8%. In 42%/IVIG- patient or 34.9%/embryo transfer, we observed a live born baby. The live born rate per embryo was 16.6%. In accordance with the study of Kwak et al., we indicate a decrease in the NK cells in patients with improved pregnancy outcome. CONCLUSION: In a subgroup of RIF-patients with high level of CD56(+) CD16(+) NK-cells the additional application of IVIG leads to a favourable pregnancy outcome.

Outcome of intracytoplasmic sperm injection with and without polar body diagnosis of oocytes.

OBJECTIVE: To compare the reproductive outcome of women undergoing intracytoplasmic sperm injection (ICSI) with or without polar body diagnosis of oocytes. DESIGN: Nonrandomized retrospective study. SETTING: University-based human genetic institute in collaboration with a private fertility center. PATIENT(S): Six hundred seven women undergoing ICSI with polar body diagnosis and 591 women undergoing ICSI without polar body diagnosis at the same time in the same fertility center. INTERVENTION(S): Polar body testing of ICSI oocytes by five-color fluorescence in situ hybridization. MAIN OUTCOME MEASURE(S): Pregnancy rate (positive fetal heartbeats) and live-birth rate (of at least one child). RESULT(S): The pregnancy and live-birth rates were significantly lower in women undergoing ICSI with polar body diagnosis than in women without polar body diagnosis. The negative effects of polar body diagnosis were evident in all analyzed subgroups, that is, women of different age groups, with one ICSI cycle, with transfer of a high-quality embryo, and with male factor infertility as indication for ICSI. CONCLUSION(S): Within the legal restrictions of the German embryo protection law aneuploidy testing of oocytes may not improve reproductive outcome.