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<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-536 Common variation in the PIN1 locus increases the genetic risk to suffer from Sertoli Cell Only syndrome

Study question

Are the common genetic variants located in the PIN1 region associated with human male infertility due to severe spermatogenic failure (SPGF)?

Summary answer

PIN1 gene polymorphisms may play a relevant role in the development of Sertoli Cell Only syndrome (SCO), the most extreme form of SPGF.

What is known already

PIN1 is a relevant prolyl isomerase in humans, that catalyzes cis/trans isomerization of peptide bonds. It has a central role in cell cycle progression and cancer, and it has been linked to the immune system promoting inflammation and reactive-oxygen species. Pin1 gene is highly expressed in adult mice testes, particularly in spermatogonia and Sertoli cells, and it is required to control the proliferation of spermatogonial stem cells. Additionally, it controls the integrity of the blood-testis barrier, helping to maintain the immune privilege of the testis. Nevertheless, mutations in PIN1 have not yet been described in human male infertility cases.

Study design, size, duration

A genetic association study was performed including samples from 715 men diagnosed with SPGF and classified as suffering from non-obstructive azoospermia (NOA, n = 505) or severe oligospermia (SO, n = 210), and 1,058 matched unaffected male controls from the Iberian Peninsula (Spain and Portugal). Allelic association on SPGF susceptibility were evaluated by testing three PIN1 single nucleotide polymorphisms (SNPs; rs2287839, rs2233678, and rs62105751), which tagged most of the common genetic variation present in this locus.

Participants/materials, setting, methods

Participants signed an informed written consent approved by the ethical committees of each participating center. SO and NOA were clinically defined according to the guidelines of the World Health Organization. Genomic DNA from blood samples was genotyped using TaqMan assays and statistical analyses were carried out by the means of logistic regression models. An in silico functional prioritization of the associated variants and their linked polymorphisms was also performed.

Main results and the role of chance

A subtype-specific genetic association with the subset of NOA patients classified as suffering from SCO was identified for the three analyzed genetic variants under the additive model (rs2287839: P = 1.94E-02, rs2233678: P = 1.94E-02, rs62105751: P = 1.94E-02). The minor alleles showed strong risk effects for this subset (rs2287839: OR = 1.85 [1.17-2.93], rs2233678: OR = 1.62 [1.11-2.36], rs62105751: OR = 1.43 [1.06-1.93]). Dependence analysis showed that all associated variants tagged the same signal. The variants underlying the identified association signal were prioritized based on their functional impact on the PIN1 locus, being rs3810166 the most likely candidate for functionality. The minor allele of such variant (G) is in linkage disequilibrium with the observed rs2287839-G risk allele and it is predicted to affect both gene expression and isoform balance of PIN1. The rs3810166 SNP likely influences the binding affinity of both HDAC2 and NRSF transcription factors, which are involved in cell cycle progression and transcription, respectively. Moreover, the tagged variants rs28802413 and rs10425775 were also predicted to alter the binding of significant transcription factors of the spermatogenic process, such as SIN3A and NANOG.

Limitations, reasons for caution

Although the overall statistical power of the study cohort was appropriate to detect the expected effects, the sample sizes in the subtype analyses were considerably lower, which may influence the obtained results. Further analyses including a larger SCO cohort should be performed to confirm our findings.

Wider implications of the findings

The obtained results shed light into the genetic contribution of common variation to male infertility, which may contribute to design a future panel of genetic markers to predict the testicular sperm extraction outcome, avoiding surgical interventions in NOA cases in which the probability of spermatozoa finding is much reduced.

Trial registration number

Not applicable

Embryologists' health: a nationwide online questionnaire

PURPOSE

The present study evaluates health status and its relation with occupational characteristics and with burnout syndrome among embryologists.

METHODS

A cross-sectional design was used to conduct an online self-assessment survey, sent to all members of the Spanish Association of Clinical Embryologists. The questionnaire contained occupational questions and two standard instruments: 'Short Form-12 Health Survey' as a measure of physical (PCS-12) and mental (MCS-12) health and the Maslach Burnout Inventory-General Survey (MBI-GS) to evaluate the degree of burnout.

RESULTS

The PCS-12 obtained for the Spanish embryologists was higher than that for the reference population. However, the total MCS-12 was significantly lower than that observed in non-institutionalised males and females representative of the general Spanish population aged 35-44 years. In the linear regression model, the dependent variable PCS-12 was related indirectly with the variables number of hours worked per week, BMI, back pain, leg pain and visual discomfort. In the linear regression model, the dependent variable MCS-12 was indirectly related to the gender (male reference; female coefficient regression: -3.23), exhaustion and cynicism dimensions of the MBI-GS. A total of 87 (36.3%) embryologists presented a high score on at least one of the MBI-GS dimensions.

CONCLUSION

In this sample of Spanish embryologists, a norm measure (SF-12) showed their physical health to be better than the average for the general population, but that their mental health was poorer. A significant indirect relation was observed between mental health and burnout syndrome. Strategies to reduce occupational stress and problems should form part of the training provided for clinical embryologists.

Genetic testing of sperm donors for cystic fibrosis and spinal muscular atrophy: evaluation of clinical utility

OBJECTIVE

To evaluate the clinical utility of genetic testing for cystic fibrosis (CF) and spinal muscular atrophy (SMA) in sperm donors.

STUDY DESIGN

We studied the results of the genetic tests for CF and SMA applied to 372 sperm donor candidates. The CF carrier screening test analysed 32 mutations on the CFTR gene. Regarding SMA, the carrier test studied possible deletions of SMN1/2 by Multiplex Ligation-dependent Probe Amplification (MLPA) methodology.

RESULTS

The carrier frequency obtained was greater for SMA than for CF. After adjusting the results obtained for the sensitivity of the tests, and taking into account the prevalence of female carriers in our population, the probability of transmission of the disease to the child from a donor with a negative genetic test was about five times lower in the case of SMA than in CF, although this difference was not statistically significant. The number of donors needed to screen (NNS) to avoid the occurrence of a child being affected by CF and SMA in our population was similar in both cases (1591 vs. 1536).

CONCLUSIONS

This study demonstrates the need to include SMA among the diseases for which genetic screening is performed in the process of sperm donor selection. We believe that testing donors for SMA is as important and as useful as doing so for CF.

Expression of integrin fraction and adhesion molecules on human granulosa cells and its relation with oocyte maturity and follicular steroidogenesis

PURPOSE

To study the correlation between the expression of integrin fractions and adhesion molecules on granulosa cells (GC) and follicular development.

METHODS

GC and follicular fluid (FF) were obtained at oocyte retrieval for ICSI. Expression of adhesion molecules on GC was studied by flow cytometry. Statistics were evaluated using the Student t test and simple linear regression analysis.

RESULTS

alpha5 integrin fraction was significantly (p < 0.01) higher, while alpha6 fraction and CD9 were significantly (p < 0.01 and p < 0.001, respectively) lower in GC from FF with metaphase II oocytes. A direct significant correlation was observed between FF progesterone and the alpha5 expression on GC (r = 0.54). In contrast, an inverse significant correlation was observed between FF progesterone level and the expression of alpha6 and CD9 (r = -0.40 and -0.41, respectively).

CONCLUSIONS

The expression pattern for integrin fractions and adhesion molecules may be of predictive value in assessing the state of differentiation of the human follicle.