Altered helper T cell-mediated immune responses in male mice conceived through in vitro fertilization

Long-Term Effects of ART on the Health of the Offspring

Assisted reproductive technologies (ART) significantly increase the chance of successful pregnancy and live birth in infertile couples. The different procedures for ART, including in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), intrauterine insemination (IUI), and gamete intrafallopian tube transfer (GIFT), are widely used to overcome infertility-related problems. In spite of its inarguable usefulness, concerns about the health consequences of ART-conceived babies have been raised. There are reports about the association of ART with birth defects and health complications, e.g., malignancies, high blood pressure, generalized vascular functional disorders, asthma and metabolic disorders in later life. It has been suggested that hormonal treatment of the mother, and the artificial environment during the manipulation of gametes and embryos may cause genomic and epigenetic alterations and subsequent complications in the health status of ART-conceived babies. In the current study, we aimed to review the possible long-term consequences of different ART procedures on the subsequent health status of ART-conceived offspring, considering the confounding factors that might account for/contribute to the long-term consequences.

Gestational and health outcomes of dairy cows conceived by assisted reproductive technologies compared to artificial insemination

Herd gestation and health management are key aspects of effective dairy farm operations and animal welfare improvement. Unfortunately, very little is known about the developmental divergences induced by assisted reproduction technologies (ART) and their consequences once the animal is mature. Indeed, the gestational and health outcomes of this subset of the Holstein population is yet to be characterized. In this study, the intergenerational impacts of ART conception were assessed by looking at the gestation and health outcomes of a large cohort of cows (n = 284,813) for which the conception methods were known. Our results showed that cows conceived by multiple ovulation embryo transfer (MOET) and in vitro fertilisation (IVF) displayed longer gestations: +0.37 ± 0.079 and +0.65 ± 0.21 day compared to cows conceived by artificial insemination (AI). Surprisingly, animals conceived by all methods experienced a similar 1-day decline in average gestation length from 2012 to 2019. Cows conceived by IVF were not more likely to experience stillbirths but were affected by common diseases such as ovarian cysts, mastitis, and uterine diseases in different proportions compared to cows conceived by other methods. This study provides new and unique information on ART animals regarding perinatal mortality and general health outcomes.

Early childhood respiratory tract infections according to parental subfertility and conception by assisted reproductive technologies

STUDY QUESTION

Are children conceived by ART or born to subfertile parents more susceptible to upper or lower respiratory tract infections (URTI, LRTI)?

SUMMARY ANSWER

ART-conceived children had a higher frequency of and risk of hospitalization for respiratory infections up to age 3, which was only partly explained by parental subfertility.

WHAT IS KNOWN ALREADY

Some studies report increased risks of infections in children conceived by ART. Results for URTIs and LRTIs are inconclusive, and the contribution of underlying parental subfertility remains unclear.

STUDY DESIGN, SIZE, DURATION

We included 84 102 singletons of the Norwegian Mother, Father and Child Cohort Study (MoBa) born between 1999 and 2009. Mothers reported time-to-pregnancy at recruitment and child history of, frequency of and hospitalization for, respiratory infections when the child was 6, 18 and 36 months old by questionnaires. Subfertility was defined as having taken 12 or more months to conceive. The Medical Birth Registry of Norway (MBRN) provided information on ART. URTI included throat and ear infections, while LRTI included bronchitis, bronchiolitis, respiratory syncytial virus and pneumonia.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We used log-binomial regression to estimate risk ratios (RR) and 95% CI of any respiratory tract infection and hospitalization, and negative-binomial regression to calculate incidence rate ratios (IRR) and 95% CI for number of infections. We compared children conceived by ART, and naturally conceived children of subfertile parents, to children of fertile parents (<12 months to conceive) while adjusting for maternal age, education, BMI and smoking during pregnancy and previous livebirths. We accounted for dependency between children born to the same mother.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 7334 (8.7%) singletons were naturally conceived by subfertile parents and 1901 (2.3%) were conceived by ART. Between age 0 and 36 months, 41 609 (49.5%) of children experienced any URTI, 15 542 (18.5%) any LRTI and 4134 (4.9%) were hospitalized due to LRTI. Up to age 3, children conceived by ART had higher frequencies of URTI (adjusted IRR (aIRR) 1.16; 95% CI 1.05–1.28) and hospitalizations due to LRTI (adjusted RR (aRR) 1.25; 95% CI 1.02–1.53), which was not seen for children of subfertile parents. Children conceived by ART were not at higher risks of respiratory infections up to age 18 months; only at age 19–36 months, they had increased risk of any LRTI (aRR 1.16; 95% CI 1.01–1.33), increased frequency of LRTIs (IRR 1.22; 95% CI 1.02–1.47) and a higher risk of hospitalization for LRTI (aRR 1.35; 95% CI 1.01–1.80). They also had an increased frequency of URTIs (aIRR; 1.19; 95% CI 1.07–1.33). Children of subfertile parents only had a higher risk of LRTIs (aRR 1.09; 95% CI 1.01–1.17) at age 19–36 months.

LIMITATIONS, REASONS FOR CAUTION

Self-reported time-to-pregnancy and respiratory tract infections by parents could lead to misclassification. Both the initial participation rate and loss to follow up in the MoBa limits generalizability to the general Norwegian population.

WIDER IMPLICATIONS OF THE FINDINGS

ART-conceived children might be more susceptible to respiratory tract infections in early childhood. This appears to be only partly explained by underlying parental subfertility. Exactly what aspects related to the ART procedure might be reflected in these associations need to be further investigated.

STUDY FUNDING/COMPETING INTEREST(S)

Funding was received from the Swiss National Science Foundation (P2BEP3_191798), the Research Council of Norway (no. 262700), and the European Research Council (no. 947684). All authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Effect of Sperm Cryopreservation on miRNA Expression and Early Embryonic Development

Although sperm preservation is a common means of personal fertility preservation, its effects on embryonic development potential need further investigation. The purpose of this study was to identify key microRNA (miRNA) in cryopreserved sperm and determine the changes of these miRNAs and their target genes during embryonic development using cryopreserved sperm. Moreover, the embryonic development potential of cryopreserved sperm was estimated in assisted reproductive technology (ART), where key miRNAs and target genes were validated in sperm and subsequent embryos. Clinical data of embryonic development from cryopreserved sperm indicated a significant decrease in fertilization rate in both in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cases, as well as a reduction in blastocyst formation rate in ICSI cases. Meanwhile there was a significant increase in blocked embryo ratio of Day1, Day2, and Day3.5 embryos when frozen-thawed mouse sperm was used, compared with fresh mouse sperm, suggesting a potential negative effect of sperm cryopreservation on embryonic development. From frozen-thawed and fresh sperm in humans and mice, respectively, 21 and 95 differentially expressed miRNAs (DEmiRs) were detected. miR-148b-3p were downregulated in both human and mouse frozen-thawed sperm and were also decreased in embryos after fertilization using cryopreserved sperm. Target genes of miR-148b-3p, Pten, was identified in mouse embryos using quantitative real-time PCR (qRT-PCR) and Western blot (WB). In addition, common characters of cryopreservation of mouse oocytes compared with sperm were also detected; downregulation of miR-148b-3p was also confirmed in cryopreserved oocytes. In summary, our study suggested that cryopreservation of sperm could change the expression of miRNAs, especially the miR-148b-3p across humans and mice, and may further affect fertilization and embryo development by increasing the expression of Pten. Moreover, downregulation of miR-148b-3p induced by cryopreservation was conserved in mouse gametes.

Genome-Wide Analysis of DNA Methylation in Buccal Cells of Children Conceived through IVF and ICSI

Early life periconceptional exposures during assisted reproductive technology (ART) procedures could alter the DNA methylation profiles of ART children, notably in imprinted genes and repetitive elements. At the genome scale, DNA methylation differences have been reported in ART conceptions at birth, but it is still unclear if those differences remain at childhood. Here, we performed an epigenome-wide DNA methylation association study using Illumina InfiniumEPIC BeadChip to assess the effects of the mode of conception on the methylome of buccal cells from 7- to 8-year-old children (48 children conceived after ART or naturally (control, CTL)) and according to the embryo culture medium in which they were conceived. We identified 127 differentially methylated positions (DMPs) and 16 differentially methylated regions (DMRs) (FDR < 0.05) with low delta beta differences between the two groups (ART vs. CTL). DMPs were preferentially located inside promoter proximal regions and CpG islands and were mostly hypermethylated with ART. We highlighted that the use of distinct embryo culture medium was not associated with DNA methylation differences in childhood. Overall, we bring additional evidence that children conceived via ART display limited genome-wide DNA methylation variation compared with those conceived naturally.

The altered immunological status of children conceived by assisted reproductive technology

BACKGROUND

With the increased use of assisted reproductive technology (ART), assessing the potential health risks of children conceived on ART important to public health. Most research in this area has focused on the effects of ART on perinatal, metabolic, and oncological risks in children. Although an increased risk of immune-related diseases has been reported in children born after ART, there are no studies on the immunological status of these children. This study aimed to evaluate the impact of different embryo transfer methods and fertilization strategies on the immune status of the offspring.

METHODS

A total of 69 children born to women treated with ART and a matched control group of 17 naturally conceived (NC) children, all aged from 3 to 6 years, were recruited in the reproductive hospital affiliated to Shandong University. The frequency of immune cells in the peripheral blood was assayed using flow cytometry; plasma cytokine levels were determined by multiplex cytokine immunoassay with human cytokine magnetic beads.

RESULTS

Compared to children born after natural conception, children born after ART had elevated interferon-γ (IFN-γ) levels, regardless of embryo transfer and fertilization strategies. Children in the fresh-embryo transfer group had significantly higher IL-4 levels and a lower ratio of IFN-γ to IL-4 than those in the NC group ((P = 0.004, 10.41 ± 5.76 pg/mL vs 18.40 ± 7.01 pg/mL, P = 0.023, 1.00 ± 0.48 vs 0.67 ± 0.32, respectively). Similar results were shown in either the in vitro fertilization (IVF) group or the intra-cytoplasmic sperm injection (ICSI) group (P < 0.05 and P = 0.08 for IVF; P < 0.05 and P < 0.05 for ICSI, respectively). These alterations in IL-4 concentrations and the ratio of IFN-γ to IL-4 were statistically significantly correlated with supra-physical E₂ (estradiol) levels on the day of hCG administration (R = 0.502, P = 0.017; R = - 0.537, P = 0.010, respectively). Consistently, the frozen embryo transfer did not result in alterations of these immune indicators in the offspring. Overall, there were no significant differences between the ART group and NC group in the frequencies of T cells, B cells, natural killer (NK) cells, CD4⁺T cells, CD8⁺T cells, T helper (T_H)1 cells, T_H17 cells, and regulatory T (T_reg) cells and cytokine levels of IL-10 and IL-17a (all P > 0.05).

CONCLUSIONS

Immunological alterations existed in children born after the use of ART. The elevated E₂ levels before embryo implantation contributed to the increased IL-4 levels in children conceived by fresh embryo transfer. The assessment of immunological alteration is of importance to children conceived by ART for early monitoring and intervention.

Fertility treatments and offspring pediatric infectious morbidities: results of a population-based cohort with a median follow-up of 10 years

OBJECTIVE

To study the association between mode of conception and offspring infectious morbidity risk.

DESIGN

Population-based cohort study.

SETTING

Regional university medical center.

PATIENT(S)

All singleton infants born between the years 1991 and 2014 and discharged alive from the hospital.

INTERVENTION(S)

Follow-up time in the study was calculated from birth to an event, defined as the first offspring hospitalization with any infectious morbidity. All infectious diagnoses were compared between the study groups, and a multivariable survival model was created to study the association between mode of conception and offspring pediatric hospitalization with infectious morbidity, and adjusting for confounding or clinically significant variables.

MAIN OUTCOME MEASURE(S)

First offspring pediatric hospitalization with infectious morbidity.

RESULT(S)

During the study period, 242,187 newborns met the inclusion criteria: 2,603 (1.1%) of which were conceived after undergoing IVF, 1,172 (0.7%) after ovulation induction (OI), and 237,863 (98.3%) were conceived spontaneously. Mothers receiving fertility treatments were older and with higher rates of preterm births and low birthweights. The hospitalizations rates per 1,000 person years of follow-up were 16.34/1,000 person years, 11.61/1,000 person years, and 10.19/1,000 person years, among the IVF, OI, and spontaneously conceived offspring, respectively. The adjusted hazard ratios were 1.26 (95% confidence interval 1.13-1.42) and 1.14 (95% confidence interval 1.00-1.38), for the IVF and OI compared with the spontaneously conceived offspring, respectively. The model adjusted for preterm delivery, birthweight, maternal age, hypertension, diabetes, and cesarean section.

CONCLUSION(S)

Higher risk for infectious morbidity was found among offspring conceived after fertility treatments compared with spontaneously conceived offspring.

Altered TH1, TH2, TH17 balance in assisted reproductive technology conceived mice

AIM AND PURPOSE

The higher prevalence rate of different diseases may accentuate the possible alteration of the immune system in individuals conceived through the assisted reproductive technologies (ART). The present study was conducted to evaluate the TH1, TH2, TH17 balance in intracytoplasmic sperm injection (ICSI) and in vitro fertilization (IVF) - conceived mice in comparison to naturally conceived offspring.

METHODS

Mice (6-8 weeks) were divided into three groups (IVF- conceived, ICSI- conceived and naturally conceived). They were subjected to subcutaneous immunization witMycobacterium bovis Bacille Calmette-Guérin (BCG). The blood samples were taken and the sera were separated. Then the spleens were surgically removed at the time the mice were sacrificed. Serum levels of IFN-γ, IL-17A and IL-4 were detected by ELISA. Then the proportion of TCD4 cells possessing the T-bet+, GATA3+, and ROR-γt + were measured using FACS caliber flow cytometer.

RESULTS

In comparison with naturally conceived mice, intracellular expression of T-bet and serum levels of IFN-γ were significantly decreased in ART- conceived mice. Moreover, ART- conceived offspring showed marked increase in IL-4 and IL-17A.

CONCLUSION

It is concluded that compared to naturally conceived male mice, ART- conceived counterparts exhibit less efficient immune responses against BCG through further promotion of humoral and inflammatory related immune response characteristics.

Periconceptional environment and the developmental origins of disease

The concept emerging from Professor David Barker’s seminal research on the developmental origins of later-life disease has progressed in many directions since it was first published. One critical question being when during gestation might environment alter the developmental programme with such enduring consequences. Here, we review the growing consensus from clinical and animal research that the period around conception, embracing gamete maturation and early embryogenesis might be the most vulnerable period. We focus on four types of environmental exposure shown to modify periconceptional reproduction and offspring development and health: maternal overnutrition and obesity; maternal undernutrition; paternal diet and health; and assisted reproductive technology. These conditions may act through diverse epigenetic, cellular and physiological mechanisms to alter gene expression and cellular signalling and function in the conceptus affecting offspring growth and metabolism leading to increased risk for cardiometabolic and neurological disease in later life.