Gut bacteriome and mood disorders in women with PCOS

STUDY QUESTION

How does the gut bacteriome differ based on mood disorders (MDs) in women with polycystic ovary syndrome (PCOS), and how can the gut bacteriome contribute to the associations between these two conditions?

SUMMARY ANSWER

Women with PCOS who also have MDs exhibited a distinct gut bacteriome with reduced alpha diversity and a significantly lower abundance of Butyricicoccus compared to women with PCOS but without MDs.

WHAT IS KNOWN ALREADY

Women with PCOS have a 4- to 5-fold higher risk of having MDs compared to women without PCOS. The gut bacteriome has been suggested to influence the pathophysiology of both PCOS and MDs.

STUDY DESIGN, SIZE, DURATION

This population-based cohort study was derived from the Northern Finland Birth Cohort 1966 (NFBC1966), which includes all women born in Northern Finland in 1966. Women with PCOS who donated a stool sample at age 46 years (n = 102) and two BMI-matched controls for each case (n = 205), who also responded properly to the MD criteria scales, were included.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 102 women with PCOS and 205 age- and BMI-matched women without PCOS were included. Based on the validated MD criteria, the subjects were categorized into MD or no-MD groups, resulting in the following subgroups: PCOS no-MD (n = 84), PCOS MD (n = 18), control no-MD (n = 180), and control MD (n = 25). Clinical characteristics were assessed at age 31 years and age 46 years, and stool samples were collected from the women at age 46 years, followed by the gut bacteriome analysis using 16 s rRNA sequencing. Alpha diversity was assessed using observed features and Shannon's index, with a focus on genera, and beta diversity was characterized using principal components analysis (PCA) with Bray-Curtis Dissimilarity at the genus level. Associations between the gut bacteriome and PCOS-related clinical features were explored by Spearman's correlation coefficient. A P-value for multiple testing was adjusted with the Benjamini-Hochberg false discovery rate (FDR) method.

MAIN RESULTS AND THE ROLE OF CHANCE

We observed changes in the gut bacteriome associated with MDs, irrespective of whether the women also had PCOS. Similarly, PCOS MD cases showed a lower alpha diversity (Observed feature, PCOS no-MD, median 272; PCOS MD, median 208, FDR = 0.01; Shannon, PCOS no-MD, median 5.95; PCOS MD, median 5.57, FDR = 0.01) but also a lower abundance of Butyricicoccus (log-fold changeAnalysis of Compositions of Microbiomes with Bias Correction (ANCOM-BC)=-0.90, FDRANCOM-BC=0.04) compared to PCOS no-MD cases. In contrast, in the controls, the gut bacteriome did not differ based on MDs. Furthermore, in the PCOS group, Sutterella showed positive correlations with PCOS-related clinical parameters linked to obesity (BMI, r2=0.31, FDR = 0.01; waist circumference, r2=0.29, FDR = 0.02), glucose metabolism (fasting glucose, r2=0.46, FDR < 0.001; fasting insulin, r2=0.24, FDR = 0.05), and gut barrier integrity (zonulin, r2=0.25, FDR = 0.03).

LIMITATIONS, REASONS FOR CAUTION

Although this was the first study to assess the link between the gut bacteriome and MDs in PCOS and included the largest PCOS dataset for the gut microbiome analysis, the number of subjects stratified by the presence of MDs was limited when contrasted with previous studies that focused on MDs in a non-selected population.

WIDER IMPLICATIONS OF THE FINDINGS

The main finding is that gut bacteriome is associated with MDs irrespective of the PCOS status, but PCOS may also modulate further the connection between the gut bacteriome and MDs.

STUDY FUNDING/COMPETING INTEREST(S)

This research was funded by the European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant Agreement (MATER, No. 813707), the Academy of Finland (project grants 315921, 321763, 336449), the Sigrid Jusélius Foundation, Novo Nordisk Foundation (NNF21OC0070372), grant numbers PID2021-12728OB-100 (Endo-Map) and CNS2022-135999 (ROSY) funded by MCIN/AEI/10.13039/501100011033 and ERFD A Way of Making Europe. The study was also supported by EU QLG1-CT-2000-01643 (EUROBLCS) (E51560), NorFA (731, 20056, 30167), USA/NIH 2000 G DF682 (50945), the Estonian Research Council (PRG1076, PRG1414), EMBO Installation (3573), and Horizon 2020 Innovation Grant (ERIN, No. EU952516). The funders did not participate in any process of the study. We have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Impact of Lactobacillus crispatus-containing oral and vaginal probiotics on vaginal health: a randomised double-blind placebo controlled clinical trial

Health of reproductive tract is tightly associated with balance of microbial communities in this area. Bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC) represent common disturbances of vaginal communities. Vaginal discharge due to BV or VVC is a very frequent reason for visiting gynaecologist. We aimed to evaluate the impact of the novel evidence-based probiotics on BV and VVC patients. The study group included 89 BV and 93 VVC patients (aged 18-50 years) who were recruited into randomised double-blind placebo-controlled two-arm parallel trial. The patients of each diagnosis group received oral or vaginal probiotic capsules, or placebo capsules during 3 months. A probiotic capsule contained two (DSM32717 and DSM32720, in case of BV) or three (DSM32720, DSM32718 and DSM32716, in case of VVC) Lactobacillus crispatus strains. Vaginal, intestinal and general health was monitored weekly by questionnaire. Blood analyses were done in the beginning and at the end of trial. Vaginal samples were collected monthly, microscopic and molecular analyses were performed. The study revealed that both oral and vaginal capsules reduced the signs and symptoms in BV patients. Remarkable improvement was noted in Nugent score, amount and smell of discharge, but also in itching/irritation. Consumption of vaginal probiotics significantly increased the lactobacilli counts in their vagina while mean proportion of some BV-related bacteria decreased. In VVC patients, both oral and vaginal capsules lowered the combined score of two most important symptoms, amount of discharge and itching/irritation. In conclusion, the novel formulations of evidence-based well-focused probiotic L. crispatus strains are effective against BV and VVC being suitable for both vaginal and oral administration. Clinical trial registration: ISRCTN34840624, BioMed Central.

Chromatin modifier developmental pluripotency associated factor 4 (DPPA4) is a candidate gene for alcohol-induced developmental disorders

BACKGROUND

Prenatal alcohol exposure (PAE) affects embryonic development, causing a variable fetal alcohol spectrum disorder (FASD) phenotype with neuronal disorders and birth defects. We hypothesize that early alcohol-induced epigenetic changes disrupt the accurate developmental programming of embryo and consequently cause the complex phenotype of developmental disorders. To explore the etiology of FASD, we collected unique biological samples of 80 severely alcohol-exposed and 100 control newborns at birth.

METHODS

We performed genome-wide DNA methylation (DNAm) and gene expression analyses of placentas by using microarrays (EPIC, Illumina) and mRNA sequencing, respectively. To test the manifestation of observed PAE-associated DNAm changes in embryonic tissues as well as potential biomarkers for PAE, we examined if the changes can be detected also in white blood cells or buccal epithelial cells of the same newborns by EpiTYPER. To explore the early effects of alcohol on extraembryonic placental tissue, we selected 27 newborns whose mothers had consumed alcohol up to gestational week 7 at maximum to the separate analyses. Furthermore, to explore the effects of early alcohol exposure on embryonic cells, human embryonic stem cells (hESCs) as well as hESCs during differentiation into endodermal, mesodermal, and ectodermal cells were exposed to alcohol in vitro.

RESULTS

DPPA4, FOXP2, and TACR3 with significantly decreased DNAm were discovered-particularly the regulatory region of DPPA4 in the early alcohol-exposed placentas. When hESCs were exposed to alcohol in vitro, significantly altered regulation of DPPA2, a closely linked heterodimer of DPPA4, was observed. While the regulatory region of DPPA4 was unmethylated in both control and alcohol-exposed hESCs, alcohol-induced decreased DNAm similar to placenta was seen in in vitro differentiated mesodermal and ectodermal cells. Furthermore, common genes with alcohol-associated DNAm changes in placenta and hESCs were linked exclusively to the neurodevelopmental pathways in the enrichment analysis, which emphasizes the value of placental tissue when analyzing the effects of prenatal environment on human development.

CONCLUSIONS

Our study shows the effects of early alcohol exposure on human embryonic and extraembryonic cells, introduces candidate genes for alcohol-induced developmental disorders, and reveals potential biomarkers for prenatal alcohol exposure.

P-409 The endometrial transcriptome of infertile women with and without recurrent implantation failure

Study question

Does the endometrial transcriptome profile differ between infertile women with or without a recurrent implantation failure (RIF)?

Summary answer

Although two different clusters emerged from the endometrial transcriptome data, these were not associated with clinical phenotype (RIF vs non-RIF).

What is known already

Despite the transfer of morphologically ‘good-quality’ embryos in IVF/ICSI, implantation failure often occurs, which may be explained by impaired endometrial receptivity. In order to guide prognosis and use effective therapeutic interventions, identifying a gene expression profile predictive of endometrial receptivity as well as implantation failure, would be of great value. Additionally, transcriptome analysis may also shed light on alterations in biological processes responsible for the implantation failure. Thousands of potential biomarkers for endometrial receptivity have already been identified by transcriptomic approach, however due to differences in study methodology, there is little overlap of markers between studies.

Study design, size, duration

Endometrial tissue was obtained from a cohort of 141 infertile women undergoing endometrial scratching within a randomised controlled trial (RCT) (SCRaTCH trial, NL5193/NTR5342). Briefly, women aged 18-44 years with failed implantation after one full IVF/ICSI cycle and planning a subsequent IVF/ICSI cycle, were eligible. Participants were followed-up until 12 months after randomisation, with the primary outcome being live birth, defined as the delivery of at least one live foetus after 24 weeks of gestation.

Participants/materials, setting, methods

Endometrial tissue was obtained with an endometrial biopsy catheter in the midluteal phase of a natural cycle preceding subsequent IVF/ICSI. Biopsies were snap-frozen and stored at -80 °C until use. After thawing, total RNA isolation, library preparation and paired-end RNA-sequencing were performed. Raw data was preprocessed and mapped to GRCh38. Reads (counts per million) were normalised using library size. Differential gene expression (DGE) analysis was conducted using the EdgeR package with significance threshold FDR &lt;0.05.

Main results and the role of chance

Out of 141 endometrium samples, 107 were included in the RNA-sequencing based on RNA quality. For DGE analysis, data of two groups were compared: the ‘fertile’ group, women with a live birth after ≤3 good quality embryo(s) transfers (n = 23), and the RIF group, women with no live birth after ≥3 good quality embryo(s) transfers (n = 23). Two clusters were visible in the principle component analysis (PCA) plot showing transcriptome data of the fertile and RIF samples (cluster 1, n = 29; cluster 2, n = 10), which was not explained by clinical phenotype, as both clusters contained samples of both the fertile and RIF group. DGE analysis between the fertile and RIF group resulted in respectively 3 significantly upregulated and 0 significantly downregulated genes, whereas DGE analysis between the two clusters resulted in 2,235 significantly upregulated and 2,162 significantly downregulated genes. Enrichment analysis of differentially expressed genes between both clusters demonstrated upregulation of enriched terms mainly annotated to cell migration and downregulation of enriched terms mainly annotated to lipid and mitochondrial metabolism.

Limitations, reasons for caution

A strength of the study is the large number of samples included. Bulk RNA-sequencing was conducted and there was a variation in LH-based timing of the biopsies (5-8 days after LH surge) for which adjustments of the transcriptome data for tissue cellular composition and menstrual cycle were performed.

Wider implications of the findings

Future studies investigating underlying biological mechanisms in the endometrium in (in)fertility by a (multi-)omics analysis approach with standardised methodology are required to obtain consistencies in relevant biomarkers/pathways, and in due course create possibilities to improve and personalise care for infertile couples.

Trial registration number

NL5193/NTR5342

P-431 Functionally active microbiota in the receptive-phase endometria in women with recurrent implantation failure

Study question

Does the functionally active microbial composition at the receptive phase endometria differ between women with recurrent implantation failure (RIF) and healthy controls?

Summary answer

Women with RIF have different functionally active microbiota in the receptive-phase endometria that are involved in distinct metabolical pathways when compared to healthy women.

What is known already

Recurrent implantation failure (RIF) is a common and burdening diagnosis in infertility treatment. Despite scientific advances in the field, the cause of RIF remains unclear and the treatment options ambiguous. Microorganisms have important role in human physiology and pathophysiology, and their potential involvement in endometrial functions and health are gaining support. Our previous work of microbiota mapping of healthy endometrium identified over 5000 functionally active microorganisms (bacteria, viruses, fungi, archaea) that participate in key metabolic pathways for embryo implantation. In the present work we focus on microbiota mapping in RIF patients, where endometrial dysfunction is suspected.

Study design, size, duration

A case-control age-match study of 20 RIF and 20 healthy controls was performed. Endometrial samples were obtained at the mid-secretory phase (LH + 7/8) using Pipelle curette.

Participants/materials, setting, methods

Total RNA sequencing (RNA-seq) was performed. R package MetagenomeSeq was used for metataxonomic microorganismal analyses and HUMAnN2 algorithm was used for functional metagenome assessment. The microbial maps were created using Kraken metagenomic sequence classification. With this approach we were able to identify and map the ‘active’ microorganisms in samples.

Main results and the role of chance

We identified a total of 4175 microorganisms in the human endometrial samples including different bacteria, fungi, viruses, and archaea. At the taxonomic level, RIF patients demonstrated a total of 180 microorganism with differential abundance when compared to controls (FDR&lt;0.05), where the biggest difference was in Streptomyces, Xanthomonas, Fusarium and Burkholderia that were significantly less detected in RIF. The metabolical functions analysis of the microbes differed significantly between the two groups, with a total of 150 different pathways, where fatty acid biosynthesis, mucin glycosylation, folate pathway and serotonin pathways were influenced in RIF.

Limitations, reasons for caution

Poly A enrichment could avoid the detection of some microorganism. However, the resolution power in microbial identification was comparable to previous metatranscriptomics published studies.

Wider implications of the findings

Our study findings are first to demonstrate that alive microbes are involved in the uterine pathology as is RIF, where different metabolic pathways could be dysregulated. This knowledge could help to develop pre-/probiotic strategies to modulate uterine environment for improving endometrial functions in RIF.

Trial registration number

not applicable

P-322 Does endometrium age? The endometrial transcriptome of advanced reproductive age patients reveals the signs of cellular ageing, altered immune response and compromised receptivity

Study question

What changes occur in the endometrium during ageing and how they may affect fertility?

Summary answer

The endometrial transcriptome of women of advanced maternal age is significantly different from the young women, indicating specific pathways involved in endometrial ageing.

What is known already

A woman’s peak reproductive years are considered in her twenties. Trending postponed family planning, unfortunately, brings more women in their late forties to fertility specialists to seek for assisted conception. In vitro fertilization (IVF) using donated oocytes is a common approach to overcome the impact of maternal age on ovarian reserve. However, even with the implementation of embryo that underwent pre-implantation genetic testing, the IVF success rate drops significantly in the late forties. It still remains unclear which age-related molecular processes take place in the endometrium and whether it may impact the ability to support embryo implantation.

Study design, size, duration

Endometrial transcriptome profiling was done in 44 women undergoing endometrial receptivity evaluation at hormonal replacement therapy before IVF. Patients younger than 29 were considered as young maternal age group (YMA, age 23-27) and women older than 45 were considered as advanced maternal age group (AMA, age 47-50).

Participants/materials, setting, methods

Endometrial biopsies were obtained on day 5 of progesterone treatment and RNA was extracted. All endometrial samples were evaluated as receptive based on the expression of 57 common endometrial receptivity markers. Study group samples (12 YMA + 12 AMA) were subject to Illumina RNA sequencing. The sequences were annotated using the RefSeq database and differential expression analysis was performed using DeSeq2.We validated our results (10 YMA + 10 AMA) usingquantitative-PCR and histological validation.

Main results and the role of chance

A total of 37228 mRNA transcripts were expressed in the analyzed endometrial samples. After multiple testing corrections, 144 significantly differentially expressed(DE) transcripts (92 up-regulated, 52 down-regulated) were identified in the endometrium of the AMA versus YMAgroup. Overexpressed genes were associated with decidualization (ALDH3A1), endometrial receptivity (EML5, GALNT12), cell cycle (CDKN2A) and signal transduction, while down-regulated genes included sugar metabolism and inflammation (C2CD4B, NFKB), cellular motility (SPAG6)and progesterone signaling (RPL9). The pathways most affected by age were cellular remodeling, cell motility and migration, and immune response. Interestingly, some of the identified DE genes have been previously associated with ageing. Our results suggest the involvement of p16-associated cellular senescence and the suppression of metabolic and inflammatory processes essential for endometrial preparation for embryo transfer.

Limitations, reasons for caution

The study includes only patients undergoing hormonal replacement therapy and it is unclear whether the same processes are affected by age in the natural cycles.

Wider implications of the findings

These findings allow us to explain the age-related molecular changes that take place in the endometrial tissue. Understanding these alterations and using them in assisted reproductive technology may help to improve infertility management in women with advanced reproductive age.

Trial registration number

None

P-591 Cellular heterogeneity in the preovulatory follicle correlates with response to stimulation with recombinant FSH and affects somatic cell gene expression levels

Study question

What is the difference in the composition and gene expression of pre-ovulatory follicular somatic cells between normo- and hyporesponder patients to rFSH stimulation?

Summary answer

Gene expression changes in the somatic cells of the preovulatory follicles of hyporesponder patients is partly attributable to distinct cell populations.

What is known already

Some women undergoing IVF respond suboptimally to the preceding ovarian stimulation without an indication of poor ovarian insufficiency nor advanced age. The gene expression levels in the somatic cells of their pre-ovulatory follicles have not been determined. However, the somatic cells play key roles in the transfer of gonadotrophin signals and in steroidogenesis. In the preovulatory follicle, being &gt;20 mm in size, the somatic cells are exposed to various molecular gradients that drive their differentiation. Due to advancements in sequencing technologies the importance of somatic cell sub-populations in the etiologies of ovarian infertility can now be investigated by bioinformatic methods.

Study design, size, duration

Consecutive IVF patients &lt;41 years of age were recruited at Nova Vita Clinic, Estonia, undergoing the antagonist stimulation protocol with rFSH administration. Ovarian puncture was performed for all patients after 36 hours of hCG stimulaton. rFSH dose &gt;200 IU per one retrieved oocyte was considered as an indication for hyporesponse. Ten normo- and 9 hyporesponder patients were enrolled.

Participants/materials, setting, methods

Cells from the follicular fluid devoid of the cumulus oocyte complex were collected by centrifugation. RNA-seq was performed on the pooled cells of all participants. The study groups were compared by differential gene expression analysis by DESeq2. Single-cell RNA-seq was performed for &gt;6000 individual cells of 3 normoresponder patients and cellular sub-populations were determined with Seurat package. CIBERTSORTx software was used to deconvolute the proportion of cell types from bulk RNA-seq data of all participants.

Main results and the role of chance

Alterations in the gene expression of ovarian somatic cells have been previously attributed to female age. We demonstrate that 407 genes are differentially expressed (FDR&lt;0.05) between normo- and hyporesponder IVF patients after age adjustment. These genes were enriched into pathways of extracellular matrix reorganization (31 genes, FDR&lt;0.005), post-translational protein phosphorylation (16 genes, FDR&lt;0.006) and regulation of insulin-like growth factor transport and uptake by insulin-like growth factor binding proteins (16 genes, FDR&lt;0.019).

In addition, the sequencing of &gt; 24 000 individual cells from 3 normoresponder patients revealed the somatic cell types of the preovulatory follicle in high resolution indicating the presence of immune cell populations (N = 4), epithelial cells, theca, cumulus cells and mural granulosa cell sub-populations (N = 7). Bioinformatic cell type deconvolution demonstrated significant differences between proportions of distinct cell sub-populations between normo- and hyporesponder patients and that several differentially expressed genes between the study groups can be attributed to a specific mural granulosa sub-population.

Limitations, reasons for caution

The number of study participants is small due to the high cost of the study methods.

Wider implications of the findings

The study demonstrates that hyporesponse to stimulation is associated with age-unrelated disturbances in gene expression of preovulatory somatic cells and that different somatic cell populations may have important underlying functions in the ovarian etiologies of infertility.

Trial registration number

not applicable

Endometriosis and irritable bowel syndrome: similarities and differences in the spectrum of comorbidities

STUDY QUESTION

Do the spectrum and prevalence of comorbidities of endometriosis and irritable bowel syndrome (IBS) overlap?

SUMMARY ANSWER

Despite several overlapping symptoms, the most significantly associated comorbidities of endometriosis and IBS are different and are rather related to the organ systems primarily involved in the index diagnosis.

WHAT IS KNOWN ALREADY

Endometriosis and IBS both have several similar unspecific symptoms, such as recurrent abdominal pain, cramping and anxiety, and both diseases affect young women and are associated with a number of comorbidities causing a poor quality of life. However, a detailed study, revealing the full spectrum of endometriosis and IBS comorbidities in the same study population, is lacking.

STUDY DESIGN, SIZE, DURATION

This article presents a retrospective in silico analysis of the data from a large nationwide biobank-based cohort consisting of 121 773 women. After excluding all first- and second-degree relatives, the data of up to 65 421 women were analyzed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

International Classification of Disease-10 diagnosis main codes associated with endometriosis (N80) and IBS (K58) diagnoses were identified from the Estonian Biobank dataset by linking with the Estonian Health Insurance Fund and other relevant registries. The associations between N80 and K58 and other diagnosis codes were tested using logistic regression, adjusting for age at recruitment and 10 genetic principal components to account for potential population stratification. Bonferroni correction was applied to account for multiple testing.

MAIN RESULTS AND THE ROLE OF CHANCE

Both women with endometriosis and IBS suffered from more conditions compared to the control group, with 226 and 428 diagnosis codes statistically significantly more frequent in women with respective diagnosis compared to controls. Women suffering from both conditions had 275 significantly associated comorbidities. A remarkable proportion of women with IBS or endometriosis suffered also from endometriosis (9.0%) or IBS (13.6%), respectively. In endometriosis, the most prevalent diagnoses were related to diseases of the genitourinary system (33 N-category codes) and in women with IBS, the most associated diagnoses were related to digestive disorders and gastrointestinal tract (52 codes from K-category). Among the most significant diagnoses in endometriosis were uterine leiomyomas (D25), menstrual disorders (N92) and infertility (N97) (P < 1 × 10-315 for all), and in IBS, lactose intolerance (E73), gastritis and duodenitis (K29) and functional dyspepsia (K30) were in the top list of most significant comorbidities (P < 1 × 10-315 for all).

LIMITATIONS, REASONS FOR CAUTION

The information about the severity stages of endometriosis and subtypes of IBS was not available for analysis. The findings may not be fully extrapolated to all female populations, because all participants were from one geographic area and had good access to health services.

WIDER IMPLICATIONS OF THE FINDINGS

These findings support previous studies that have found a high prevalence of pre-selected comorbidities in women with endometriosis and IBS. However, taking into account the differences in the full spectrum of comorbidities of endometriosis and IBS may aid in diagnosing these disorders. Women and healthcare providers need to be aware that women with endometriosis are at high risks of complications during pregnancy and should be carefully monitored.

STUDY FUNDING/COMPETING INTEREST(S)

This research was funded by the Estonian Research Council (grant PRG1076), Horizon 2020 innovation grant (ERIN, grant no. EU952516), Enterprise Estonia (grant no. EU48695), MSCA-RISE-2020 project TRENDO (grant no. 101008193) and by the European Union through the European Regional Development Fund (Projects no. 2014-2020.4.01.15-0012 and no. 2014-2020.4.01.16-0125). The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

The mid-secretory endometrial transcriptomic landscape in endometriosis: a meta-analysis

STUDY QUESTION

Do women with endometriosis have a different endometrial gene expression profile at the time of embryo implantation than women without endometriosis?

SUMMARY ANSWER

The endometrial gene expression profile of women with endometriosis differs from that of women without endometriosis at the mid-secretory phase, although the differences are small.

WHAT IS KNOWN ALREADY

About 50% of women with endometriosis suffer infertility. Several molecular studies have suggested impaired endometrial receptivity in women with endometriosis, while others have detected no dysregulation of endometrial receptivity. Nevertheless, the previous endometrial transcriptome studies comparing women with and without endometriosis have been performed in small sample size with limited statistical power. We set out to systematically search and compile data of endometrial gene expression signatures at the receptive phase in women with endometriosis versus control women. Based on the obtained data, we conducted a meta-analysis of differentially expressed genes in order to raise the power of the analysis for identifying the molecular profiles of receptive phase endometria in endometriosis.

STUDY DESIGN, SIZE, DURATION

A systematic literature search was conducted up to February 2022 following PRISMA criteria and included PubMed, Cochrane and Web of Science databases. For the systematic search, the term ‘endometriosis’ was paired with the terms ‘transcriptomics’, ‘transcriptome’, ‘gene expression’, ‘RNA-seq’, ‘sequencing’ and ‘array’, by using the Boolean operator ‘AND’ to connect them. Articles written in English were screened and interrogated for data extraction.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A meta-analysis was performed on the selected studies to extract the differentially expressed genes described at the mid-secretory phase in women with endometriosis versus women without endometriosis in natural cycles, using the robust rank aggregation method. In total, transcriptome data of 125 women (78 patients and 47 controls) were meta-analysed, with a special focus on endometrial receptivity-specific genes based on commercial endometrial receptivity tests.

MAIN RESULTS AND THE ROLE OF CHANCE

In total, 8 studies were eligible for the quantitative meta-analysis, gathering transcriptome data from the mid-secretory phase endometria of 125 women. A total of 7779 differentially expressed transcripts between the study groups were retrieved (3496 up-regulated and 4283 down-regulated) and were meta-analysed. After stringent multiple correction, there was no differential expression of any single molecule in the endometrium of women with endometriosis versus controls, while enrichment analysis detected that the pathways of chemotaxis and locomotion are dysregulated in endometriosis. Further analysis of endometrial receptivity-specific genes highlighted dysregulation of C4BPA, MAOA and PAEP and enrichment of immune and defence pathways in women with endometriosis.

LIMITATIONS, REASONS FOR CAUTION

Most of the studies included into the meta-analysis were relatively small and had different study designs, which might have contributed to a bias.

WIDER IMPLICATIONS OF THE FINDINGS

The current meta-analysis supports the hypothesis that endometrial receptivity is altered in women with endometriosis, although the changes are small. The molecules and pathways identified could serve as future biomarkers and therapeutical targets in detecting and treating endometriosis-associated infertility.

STUDY FUNDING/COMPETING INTEREST(S)

The authors declare no competing interests. This work was supported by the Spanish Ministry of Education, Culture and Sport [grant FPU15/01193] and the Margarita Salas program for the Requalification of the Spanish University system [grant UJAR01MS]; Spanish Ministry of Economy, Industry and Competitiveness (MINECO) and European Regional Development Fund (FEDER): grants RYC-2016-21199 and ENDORE SAF2017-87526-R; Programa Operativo FEDER Andalucía (B-CTS-500-UGR18; A-CTS-614-UGR20); the Junta de Andalucía [BIO-302; and PAIDI P20_00158]; the University of Jaén [PAIUJA-EI_CTS02_2017]; the University of Granada, Plan Propio de Investigación 2016, Excellence actions: Units of Excellence; Unit of Excellence on Exercise and Health (UCEES), and by the Junta de Andalucía, Consejería de Conocimiento, Investigación y Universidades and European Regional Development Fund (ERDF), ref. SOMM17/6107/UGR; the Estonian Research Council (grant PRG1076); Horizon 2020 innovation (ERIN, grant no. EU952516) of the European Commission and Enterprise Estonia (grant EU48695).

TRIAL REGISTRATION NUMBER

The systematic review was registered at PROSPERO (identifier: CRD42020122054).

P–381 Deciphering the genetic cause of recurrent and sporadic pregnancy loss

Study question

To investigate the prevalence and effect of (mosaic) de novo genomic aberrations in recurrent pregnancy loss (RPL) and sporadic abortion (SA).

Summary answer

Prevalence of maternal uniparental disomies (UPDs) was high in both cohorts. While chromosomal UPDs were found in both cohorts, genome wide UPDs were RPL specific.

What is known already

Spontaneous abortion occurs in 10–15% of clinically recognized pregnancies and recurrent pregnancy loss in 1–3%. SA and RPL are associated with reduced quality of life. Multiple factors contribute to SA and RPL, such as uterine malformations and parental/fetal chromosomal abnormalities. However, in ∼60% of SA and RPL the cause remains unknown. UPD is defined as the presence of two homologues chromosomes originating from a single parent. This phenomenon can lead to imprinting disorders that are characterised by clinical features affecting growth, development and metabolism in liveborn offspring. However, it could also be responsible for pregnancy loss.

Study design, size, duration

We recruited 32 families with pregnancy loss (n = 16 RPL cohort, n = 16 SA cohort) with no known genetic predispositions and normal karyotyping results in both parents and the fetus. Average maternal age was 28.68 years (SD = 5.43), paternal age 30.3 years (SD = 5.53), and the gestational age at pregnancy loss was 8.65 weeks (SD = 2.47). The average number of miscarriages in the RPL group was 3.57 (SD = 0.84). We profiled the genomic landscape of both cohorts using SNP typing.

Participants/materials, setting, methods

We isolated DNA from blood of both parents and the placental tissues from the miscarried products of conception. The placenta tissues were sampled from two distinct extraembryonic and embryonic germ layers, the extraembryonic mesoderm and the chorionic villi cytotrophoblast. Subsequently, we performed SNP-genotyping using Illumina’s Global-Screening Array–24 v2.0 BeadChips and applied haplarithmisis to delineate allelic architecture of fetal tissues of both cohorts. This allowed us to detect large de novo copy-number and -neutral (&gt;10kb) changes.

Main results and the role of chance

In this pilot study, we have analyzed 132 DNA samples (n = 32 families), of which 16 families were in the RPL cohort and 16 in the SA cohort. Within the RPL cohort, we found: one family with mosaic genome wide hexaploidy both in the extraembryonic mesoderm and chorionic villi, one family with a non-mosaic genome wide hetero UPD of the chorionic villi tissue, one family with a mosaic UPD of chromosome 14 in both tissues and tetraploidy exclusively in the chorionic villi, one family with a mosaic UPD of chromosome 16 in both tissues, one family with a mosaic UPD of chromosome 6 in both tissues, and another family with a mosaic UPD of chromosome 5 in the extraembryonic mesoderm. Within the SA group, one family showed a UPD of chromosome 7 and another family showed a segmental UPD of chromosome 5 in both tissues. Strikingly, all the UPDs found in this study were maternal in origin.

Limitations, reasons for caution

The main limitation of this study is the resolution of detecting copy-neutral and copy-number variations, which is an inherent limiting factor of SNP-array technology. In addition, in the sample in which we observed non-mosaic genome wide UPD, maternal contamination is likely that can be investigated by other technologies.

Wider implications of the findings: Multiple genome wide UPDs are found in the RPL group but none in the SA group, indicating an association between genome wide mosaic UPD and RPL. These findings could lead to a better understanding of causative factors for SA and RPL and the need for a SNP-based non-invasive prenatal testing.

Trial registration number

Not applicable

P–290 Time-course analysis of endometrial miR/isomiR expression dynamics during hCG-primed menstrual-cycle phase transitions

Study question

What is the qualitative and quantitative profile of microRNAs (miR) and their sequence variants - isomiRs, and how it changes during the menstrual-cycle phase transitions?

Summary answer

Time-course analysis of endometrial miR/isomiR profiles has shown that menstrual-phase transitions cause widespread and complex changes in miR gene expression and processing.

What is known already

Embryo implantation depends on the receptivity of the endometrium during the window of implantation, when ovarian hormones and genetic factors coordinate the development of the uterine lining and prepare it for embryo implantation. The most important factors for successful implantation studied so far are the embryo itself, the histological dating of the endometrium and its molecular genetic characteristics, including miRs. With the rapid development of next-generation sequencing technologies, it has become clear that miR genes have the potential to produce not only miR but also variants (isomiRs) thereof, which can differ in sequence and length and can be functionally significant.

Study design, size, duration

miR/isomiR landscape was assessed by small RNA sequencing of endometrial biopsy samples at 4 time points of endometrial cycle covering the proliferative and secretory phases. Healthy, fertile, female volunteers took part in the study lasting one and a half years. For accurate phase dating, human chorionic gonadotropin (hCG) was administrated, and ultrasonic, histological and hormonal assessments were done at each time point. Statistically significant data of miR/isomiR identification and expression dynamics was considered for analysis.

Participants/materials, setting, methods

Participant choice criteria - at least one child born, problem-free pregnancies, no diseases or allergies; hCG application time determined according follicle and endometrium ultrasound scanning, and ovarian hormone levels; endometrial biopsies taken at hGC (before hormone application), hGC+2, hGC+7, hGC+9 time points; small RNAseq completed by Karolinska Institute, Sweden; miR/isomiR identified using local Galaxy instance with an in-built workflow and tools developed by our laboratory; differential expression and target prediction evaluated with DESeq2 and miRDB,resp.

Main results and the role of chance

Within the cohort of patients, across the four study time points, the small RNAseq data revealed numbers of miRs and isomiRs to be changed. The largest statistically significant changes in their expression were found at LH + 9. The miR families that showed the largest number of members with altered expression were miR125a, miR30d, miR449c, miR92a/b and miR99a. The expression levels tended to decrease in the miR125a and miR92a families and to increase in the miR10a and miR449c families during the three studied time points of the cycle compared to the proliferative phase. Among those affected, the number of isomiRs, including templated and non-templated isomiRs, was much higher than that of miRs. For example, the ratio of the significantly altered miRs/templated isomiRs/non-templated isomiRs was 6/16/11 at LH + 9. Templated isomiRs of hsa-miR–148a–3p, hsa-miR–30d–5p and hsa-miR–449c–5p were among the most upregulated, while several templated and non-templated isomiRs of hsa-miR–125–5p were the most downregulated at LH + 9. Of particular interest are those isomiRs, in which the seed site is shifted compared to the reference miRs and results in altered target transcripts. Target prediction of the most affected isomiR of hsa-miR–449c–5p identified new targets of target scores much higher than of the reference miR.

Limitations, reasons for caution

IsomiRs are a source of novel biomarkers for clinical diagnosis. An important next step is the validation of the in-silico predicted miRs/isomiRs and their target transcripts by RT-qPCR in larger number of individuals. Expression profiles should be associated with the dominant cell type in the endometrial biopsy preparation.

Wider implications of the findings: MiR/isomiR signatures, together with those of their target mRNAs, can be applied to distinguish the endometrial phases, especially the implantation window, as well as for diagnosing endometrial dysfunction. It is worth investigating the possibility of miRs/isomiRs being used as biomarkers not only in endometrial biopsy but also in liquid biopsy.

Trial registration number

The Bulgarian National Science Fund КП–06 Н31/2

Potential vaginal probiotics: safety, tolerability and preliminary effectiveness

Vaginal discharge is one of the common reasons for gynaecologist consultation, as bacterial vaginosis and candidiasis are the main causes of discharge. These patients frequently experience numerous problems due to recurrent infections, side effects and drug resistance therefore alternative drugs are needed. Our primary aim was to evaluate safety and tolerability of the potentially probiotic Lactobacillus crispatus strains in volunteer women considering themselves healthy. We also monitored the effects of these strains on vaginal health parameters and lactobacilli counts in vagina and intestine. Forty women were recruited into trial. Absence of chronic diseases was confirmed by questionnaire and blood analysis at screening visit. In randomised double-blind placebo-controlled crossover study the eligible participants were randomly allocated to one of four groups and had to consume one of the two study products (Pro I or Pro II) - a capsule containing 3 strains, 10⁹ cfu per strain, or placebo for 1 week. Treatment period was followed by 2-week washout period and continued with second treatment and washout period. Individuals receiving firstly probiotic, received later placebo and vice versa. Blood, vaginal and faecal samples were collected, and self-reported questionnaires were applied. Thirty subjects completed the trial. The probiotic capsules were well-tolerated. The Pro II intake resulted in a significant decrease in Nugent score (from median 3.0 to 2.0, mean 3.9 to 2.6, P=0.002) and reduction in Gardnerella vaginalis counts (log₁₀ 3.57 to 2.38; P=0.027). Reduction of total vaginal bacterial counts was revealed in Pro I group (log₁₀ 7.99 to 7.72; P=0.048). In conclusion, the selected vaginal L. crispatus strains are well tolerable and Pro II mixture is prospectively effective in reducing Nugent score and vaginal counts of G. vaginalis. Therefore, these strains seem to be promising candidates for development of novel evidence-based well-focused probiotics to target female urogenital tract disorders.

Copy number variation analysis detects novel candidate genes involved in follicular growth and oocyte maturation in a cohort of premature ovarian failure cases

STUDY QUESTION

Can spontaneous premature ovarian failure (POF) patients derived from population-based biobanks reveal the association between copy number variations (CNVs) and POF?

SUMMARY ANSWER

CNVs can hamper the functional capacity of ovaries by disrupting key genes and pathways essential for proper ovarian function.

WHAT IS KNOWN ALREADY

POF is defined as the cessation of ovarian function before the age of 40 years. POF is a major reason for female infertility, although its cause remains largely unknown.

STUDY DESIGN, SIZE, DURATION

The current retrospective CNV study included 301 spontaneous POF patients and 3188 control individuals registered between 2003 and 2014 at Estonian Genome Center at the University of Tartu (EGCUT) biobank.

PARTICIPANTS/MATERIALS, SETTING, METHODS

DNA samples from 301 spontaneous POF patients were genotyped by Illumina HumanCoreExome (258 samples) and HumanOmniExpress (43 samples) BeadChip arrays. Genotype and phenotype information was drawn from the EGCUT for the 3188 control population samples, previously genotyped with HumanCNV370 and HumanOmniExpress BeadChip arrays. All identified CNVs were subjected to functional enrichment studies for highlighting the POF pathogenesis. Real-time quantitative PCR was used to validate a subset of CNVs. Whole-exome sequencing was performed on six patients carrying hemizygous deletions that encompass genes essential for meiosis or folliculogenesis.

MAIN RESULTS AND THE ROLE OF CHANCE

Eleven novel microdeletions and microduplications that encompass genes relevant to POF were identified. For example, FMN2 (1q43) and SGOL2 (2q33.1) are essential for meiotic progression, while TBP (6q27), SCARB1 (12q24.31), BNC1 (15q25) and ARFGAP3 (22q13.2) are involved in follicular growth and oocyte maturation. The importance of recently discovered hemizygous microdeletions of meiotic genes SYCE1 (10q26.3) and CPEB1 (15q25.2) in POF patients was also corroborated.

LIMITATIONS, REASONS FOR CAUTION

This is a descriptive analysis and no functional studies were performed. Anamnestic data obtained from population-based biobank lacked clinical, biological (hormone levels) or ultrasonographical data, and spontaneous POF was predicted retrospectively by excluding known extraovarian causes for premature menopause.

WIDER IMPLICATIONS OF THE FINDINGS

The present study, with high number of spontaneous POF cases, provides novel data on associations between the genomic aberrations and premature menopause of ovarian cause and demonstrates that population-based biobanks are powerful source of biological samples and clinical data to reveal novel genetic lesions associated with human reproductive health and disease, including POF.

STUDY FUNDING/COMPETING INTEREST

This study was supported by the Estonian Ministry of Education and Research (IUT20-43, IUT20-60, IUT34-16, SF0180027s10 and 9205), Enterprise Estonia (EU30020 and EU48695), Eureka's EUROSTARS programme (NOTED, EU41564), grants from European Union's FP7 Marie Curie Industry-Academia Partnerships and Pathways (IAPP, SARM, |EU324509) and Horizon 2020 innovation programme (WIDENLIFE, 692065), Academy of Finland and the Sigrid Juselius Foundation.

Single-cell transcriptome analysis of endometrial tissue

STUDY QUESTION

How can we study the full transcriptome of endometrial stromal and epithelial cells at the single-cell level?

SUMMARY ANSWER

By compiling and developing novel analytical tools for biopsy, tissue cryopreservation and disaggregation, single-cell sorting, library preparation, RNA sequencing (RNA-seq) and statistical data analysis.

WHAT IS KNOWN ALREADY

Although single-cell transcriptome analyses from various biopsied tissues have been published recently, corresponding protocols for human endometrium have not been described.

STUDY DESIGN, SIZE, DURATION

The frozen-thawed endometrial biopsies were fluorescence-activated cell sorted (FACS) to distinguish CD13-positive stromal and CD9-positive epithelial cells and single-cell transcriptome analysis performed from biopsied tissues without culturing the cells. We studied gene transcription, applying a modern and efficient RNA-seq protocol. In parallel, endometrial stromal cells were cultured and global expression profiles were compared with uncultured cells.

PARTICIPANTS/MATERIALS, SETTING, METHODS

For method validation, we used two endometrial biopsies, one from mid-secretory phase (Day 21, LH+8) and another from late-secretory phase (Day 25). The samples underwent single-cell FACS sorting, single-cell RNA-seq library preparation and Illumina sequencing.

MAIN RESULTS AND THE ROLE OF CHANCE

Here we present a complete pipeline for single-cell gene-expression studies, from clinical sampling to statistical data analysis. Tissue manipulation, starting from disaggregation and cell-type-specific labelling and ending with single-cell automated sorting, is managed within 90 min at low temperature to minimize changes in the gene expression profile. The single living stromal and epithelial cells were sorted using CD13- and CD9-specific antibodies, respectively. Of the 8622 detected genes, 2661 were more active in cultured stromal cells than in biopsy cells. In the comparison of biopsy versus cultured cells, 5603 commonly expressed genes were detected, with 241 significantly differentially expressed genes. Of these, 231 genes were up- and 10 down-regulated in cultured cells, respectively. In addition, we performed a gene ontology analysis of the differentially expressed genes and found that these genes are mainly related to cell cycle, translational processes and metabolism.

LIMITATIONS, REASONS FOR CAUTION

Although CD9-positive single epithelial cells sorting was successfully established in our laboratory, the amount of transcriptome data per individual epithelial cell was low, complicating further analysis. This step most likely failed due to the high dose of RNases that are released by the cells' natural processes, or due to rapid turnaround time or the apoptotic conditions in freezing- or single-cell solutions. Since only the cells from the late-secretory phase were subject to more focused analysis, further studies including larger sample size from the different time-points of the natural menstrual cycle are needed. The methodology also needs further optimization to examine different cell types at high quality.

WIDER IMPLICATIONS OF THE FINDINGS

The symbiosis between clinical biopsy and the sophisticated laboratory and bioinformatic protocols described here brings together clinical diagnostic needs and modern laboratory and bioinformatic solutions, enabling us to implement a precise analytical toolbox for studying the endometrial tissue even at the single-cell level.

Folic acid supplementation and IVF pregnancy outcome in women with unexplained infertility

Folic acid supplements are commonly used by infertile women which leads to a positive folate status. However, the effect of folic acid supplements on pregnancy outcome in women with unexplained infertility has not been well investigated. This study evaluated folic acid supplement use and folate status in women with unexplained infertility in relation to IVF pregnancy outcome. In addition, use of folic acid supplements and folate status were compared between women with unexplained infertility and fertile, nonpregnant control women. Women with unexplained infertility used significantly more folic acid supplements and had higher median total folic acid intake from supplements compared with fertile control women (both P < 0.001). Women with unexplained infertility also had significantly higher median plasma folate and lower median plasma homocysteine concentrations than fertile women (both P < 0.001), but folic acid supplementation or folate status were not related to pregnancy outcome in women with unexplained infertility. In conclusion, folic acid supplementation or good folate status did not have a positive effect on pregnancy outcome following infertility treatment in women with unexplained infertility. Folate is one of the B vitamins which has been suggested to be related to infertility. Folic acid is an artificial form of folate which is commonly used in dietary supplements. Folic acid supplementation has been shown to increase folate concentrations and decrease concentrations of the amino acid homocysteine in the blood. Folic acid supplementation is commonly used by infertile women, but the effect on pregnancy outcome in women with a diagnosis of unexplained infertility has not been thoroughly investigated. In the present study, folic acid supplement use and folate status (concentrations of folate and homocysteine) in women with unexplained infertility were evaluated in relation to pregnancy outcome. In addition, the use of folic acid supplements and folate status were compared between women with unexplained infertility and fertile control women. Our results showed that women with unexplained infertility used considerably more folic acid supplements and had higher total folic acid intake from supplements compared with fertile control women. Women with unexplained infertility had better blood folate and homocysteine concentrations than fertile women, but folic acid supplementation or folate status were not related to pregnancy outcome following the infertility treatment. In conclusion, high folic acid intake or good folate status did not increase the possibility of a birth of a healthy baby after infertility treatment in women with unexplained infertility.

166 THE DIFFERENTIAL TRANSCRIPTOME AND ONTOLOGY PROFILES OF MURAL AND CUMULUS GRANULOSA CELLS IN STIMULATED HUMAN ANTRAL FOLLICLES

Communication between various cell types in the ovary is a prerequisite for successful folliculogenesis and ovulation. In human antral follicles, granulosa cells divide into 2 distinct cell populations: mural (enveloping the antrum, MGC) and cumulus granulosa cells (surrounding the oocyte, CGC). During infertility treatment using in vitro fertilization (IVF), granulosa cells can be retrieved during puncture of stimulated follicles offering an excellent opportunity for analysing their functional properties. The aim of this study was to compare the transcriptomes of MGC and CGC. Twenty infertile women undergoing IVF-ICSI treatment were enrolled. The MGC were obtained from follicular fluid and CGC were acquired after oocyte denudation before micromanipulation. Gene expression of both cell populations was analysed using a genome-wide transcription array. The expression profile of the 2 granulosa cell populations varied significantly: out of 28 869 transcripts, 4480 were differentially expressed (q-value < 10–4); 623 transcripts differed in their expression levels by at least 2-fold. The transcriptome of MGC showed higher expression of genes involved in immune regulation (toll-like receptors, IL18, IL17R). In CGC, pathways participating in intercellular interactions, tissue remodelling and protein degradation were more clearly distinguished (tenascin C, IGFBP5). Among the identified differentially expressed genes, several are involved in follicle development, oocyte maturation, or ovulatory processes. Our findings fit well with previously published data. The results provide a basis for future studies on intra- and intercellular signaling in the preovulatory follicle leading towards identifying methods for improving oocyte health, embryo selection, and ultimately IVF success rate. This work was supported by the Estonian Science Foundation (6498, 6585, and 7479); the Estonian Ministry of Education and Science (SF0182641s04, SF0180142Cs08, SF0180044s09, and PBGMR07903); the Estonian University of Life Sciences (P8001VLVL); the European Union Sixth Framework Programme (FP6) (LSHB-CT-2004-503243); the European Cooperation 22 in Science and Technology (COST-STSM-FA0702-03734), and the European Union through the European Regional Development Fund through the Centre of Excellence in Genomics, Estonian Biocentre, and University of Tartu. The authors acknowledge our colleagues from the Nova Vita Clinic for their assistance in sample collection and all patient volunteers for their participation in the study.

Endometrial gene expression analysis at the time of embryo implantation in women with unexplained infertility

Successful embryo implantation depends on the quality of the embryo, as well as on the receptivity of the endometrium. The aim of this study was to investigate the endometrial gene expression profile in women with unexplained infertility in comparison with fertile controls at the time of embryo implantation in order to find potential predictive markers of uterine receptivity and to identify the molecular mechanisms of infertility. High-density oligonucleotide gene arrays, comprising 44 000 gene targets, were used to define the endometrial gene expression profile in infertile (n = 4) and fertile (n = 5) women during the mid-secretory phase (day LH + 7). Microarray results were validated using real-time PCR. Analyses of expression data were carried out using non-parametric methods. Hierarchical clustering and principal component analysis showed a clear distinction in endometrial gene expression between infertile and fertile women. In total we identified 145 significantly (>3-fold change) up-regulated and 115 down-regulated genes in infertile women versus controls. Via Database for Annotation, Visualization and Integrated Discovery functional analysis we detected a substantial number of dysregulated genes in the endometria of infertile women, involved in cellular localization (21.1%) and transport (18.8%) and transporter activity (13.1%) and with major localization in extracellular regions (19.2%). Ingenuity Pathways Analysis of the gene list showed dysregulation of gene pathways involved in leukocyte extravasation signalling, lipid metabolism and detoxification in the endometria of infertile women. In conclusion, endometrial gene expression in women with unexplained infertility at the time of embryo implantation is markedly different from that in fertile women. These results provide new information on genes and pathways that may have functional significance as regards to endometrial receptivity and subsequent embryo implantation.

The differential transcriptome and ontology profiles of floating and cumulus granulosa cells in stimulated human antral follicles

Communication between various ovarian cell types is a prerequisite for folliculogenesis and ovulation. In antral follicles granulosa cells divide into two distinct populations of mural and cumulus granulosa cells (CGC), enveloping the antrum and surrounding the oocyte, respectively. Both cell types, with the mural compartment in excess, contribute to the floating granulosa cell (FGC) population in the follicular fluid. The aim of this study was to compare the transcriptomes of FGC and CGC in stimulated antral follicles obtained from 19 women undergoing IVF-ICSI procedure. FGC were obtained from follicular fluid during the follicle puncture procedure and CGC were acquired after oocyte denudation for micromanipulation. Gene expression analysis was conducted using the genome-wide Affymetrix transcriptome array. The expression profile of the two granulosa cell populations varied significantly. Out of 28 869 analysed transcripts 4480 were differentially expressed (q-value < 10(-4)) and 489 showed > or =2-fold difference in the expression level with 222 genes up-regulated in FGC and 267 in CGC. The transcriptome of FGC showed higher expression of genes involved in immune response, hematological system function and organismal injury, although CGC had genes involved in protein degradation and nervous system function up-regulated. Cell-to-cell signalling and interaction pathways were noted in both cell populations. Furthermore, numerous novel transcripts that have not been previously described in follicular physiology were identified. In conclusion, our results provide a solid basis for future studies in follicular biology that will help to identify molecular markers for oocyte and embryo viability in IVF.

Androgen receptor gene haplotype is associated with male infertility

The purpose of the current study was to evaluate the importance of androgen receptor (AR) gene haplotypes and polymorphic CAG/GGN microsatellites in the aetiology of male infertility. We genotyped six haplotype-tagging single nucleotide polymorphisms and CAG/GGN microsatellites of the AR gene in 112 infertile and 212 control Estonian men. A total of 13 AR haplotypes (HAP1-13) were identified, among which HAP4 was found to confer increased risk for male infertility (OR = 5.15, 95% CI = 1.75-15.15, p = 0.003). However, infertile patients and controls had similar lengths and distributions of both AR CAG (mean +/- SD number of repeats 21.1 +/- 2.5 vs. 21.2 +/- 2.3, respectively) and GGN (mean +/- SD number of repeats 22.5 +/- 1.5 vs. 22.4 +/- 1.9, respectively) repeats. In addition, HAP2 was associated with more CAG repeats (r = 1.17, p = 0.033) and HAP3 with fewer CAG repeats (r = -2.93, p < 0.001) than the major haplotype HAP1. HAP3 and HAP4 were associated with more GGN repeats (r = 1.35, p = 0.001 and r = 1.36, p = 0.002, respectively) than HAP1. In conclusion, our results implicated the AR-HAP4 gene haplotype in increased risk for male infertility, while no association was found between AR CAG/GGN microsatellites and impaired spermatogenesis.

Cytogenetic and molecular characterization of the derivative Y chromosome: a case study of an azoospermic patient

The success of infertility treatment depends on the underlying cause and severity of the infertility problem. The current report addresses the complex genotype-phenotype interactions in an azoospermic man. Cytogenetic, molecular cytogenetic and molecular genetic studies indicated the derivative monocentric Y chromosome with duplication of Yp11 (including SRY gene) and partial deletion of Yq11 (including azoospermia factor - AZFb-c regions) as the most probable cause of the severe testicular failure. Our study emphasizes the importance of detailed genetic analysis in male infertility evaluation and helps to estimate the outcome of infertility treatment.

Fine-scale quantification of HCG beta gene transcription in human trophoblastic and non-malignant non-trophoblastic tissues

Human chorionic gonadotropin (HCG) is produced by syncytiotrophoblast of placenta. It delays the apoptosis of corpus luteum and functions in implantation. Its possible role in male reproduction has been raised. HCG beta subunit is encoded by CGB, CGB5, CGB7 and CGB8 genes located at 19q13.3 in a common genome cluster with beta subunit non-coding CGB1 and CGB2. We conducted a sensitive quantification and comparison of CGB gene expression in human trophoblastic (blastocysts, n = 6; normal/failed pregnancy, n = 51) and non-malignant non-trophoblastic tissues (15 different tissue types, samples n = 241), by real-time RT-PCR. We showed a wide transcriptional window of CGB genes in normal pregnancy, a significant reduction in recurrent miscarriages, and a high expression (especially CGB1/CGB2) in ectopic and molar pregnancies. Expression was several orders of magnitude lower in the non-placental tissues, with the highest CGB levels being seen in testis, prostate, thymus, skeletal muscle and lung samples. The contribution of CGB1/CGB2 to the summarized expression of six CGB genes was not proportional to their gene dosage: 1/1000 to 1/10,000. An interesting exception was the testis exhibiting a much higher CGB1/CGB2 to total CGB mRNA ratio of approximately one-third, corresponding to gene dosage. In conclusion, the expressional profile of CGB genes, activated already in blastocyst stage, is associated with the status of pregnancy. The presence of CGB transcripts in testes, and in particular CGB1/CGB2 transcripts, may indicate a role in male reproductive tract.

The predictive value of pronuclear morphology of zygotes in the assessment of human embryo quality

BACKGROUND

Recent studies have shown that zygote morphology could be used for the assessment of human embryo quality. Pronuclear (PN) morphology is based on certain distinct features seen in zygotes 16-18 h after fertilization. In the present study PN stage morphology was assessed and combined with a single embryo transfer in order to investigate whether currently used zygote classifications are able to predict embryo quality and implantation rates.

METHODS AND RESULTS

Zygotes were analysed according to two different classification systems. In the first, a total of 764 zygotes was analysed according to the degree of polarization of nucleolar precursor bodies (NPB). Zygotes with unpolarized PN (i.e. scattered localization of NPB) showed significantly slower (P < 0.005) cleavage rates (38.9%) than zygotes having at least one pronucleus polarized (57.3% and 54%). However, there was no difference in the pregnancy rate in 105 single embryo transfers between the groups. The appearance of a cytoplasmic halo was related to embryo morphology. Embryos derived from halo-positive zygotes had significantly better (P < 0.05) morphology (60.9%) compared to halo-negative derived embryos (52.2%), but in terms of pregnancy rates no difference was found. A total of 1520 zygotes was analysed according to a second classification system, which was based on the number and distribution of NPB. In the comparative analysis, none of the six different classes produced superior quality embryos or higher pregnancy rates in 144 single embryo transfers.

CONCLUSIONS

Our results indicate that there are no significant differences in embryo quality or implantation/pregnancy rates between proposed zygote classes.

Studies of cellulose binding by cellobiose dehydrogenase and a comparison with cellobiohydrolase 1

The binding isotherm to cellulose of cellobiose dehydrogenase (CDH) from Phanerochaete chrysosporium has been compared with that of cellobiohydrolase 1 (CBH 1) from Trichoderma reesei. CDH binds more strongly but more sparsely to cellulose than does CBH 1. In a classical Scatchard analysis, a better fit to a one-site binding model was obtained for CDH than for CBH 1. The binding of both enzymes decreased in the presence of ethylene glycol, increased in the presence of ammonium sulphate and was unaffected by sodium chloride. Attempts to localize the cellulose-binding site on CDH have also been made by exposing enzymically digested CDH to cellulose and isolating the cellulose-bound peptides. The results suggest that the cellulose-binding site is located internally in the amino acid sequence of CDH.