In Vitro Fertilization Alters Growth and Expression of Igf2/H19 and Their Epigenetic Mechanisms in the Liver and Skeletal Muscle of Newborn and Elder Mice
TL;DR: The results indicate that IVF causes alterations in mouse growth during the postnatal periods that may be associated with alterations in Igf 2/H19 expression and likely involve the regulation of miR-483 and the methylation status of Igf2/H 19 DMRs.
Abstract: Epidemiological studies have reported a higher incidence of growth disorders among newborns conceived by in vitro fertilization (IVF), suggesting that IVF may be disruptive to the process of embryonic and fetal growth. However, the long-term effects of IVF on the growth and molecular mechanisms remain unclear. Therefore, we evaluated the body weight of IVF mice from birth to the age of 1.5 yr. In addition, we analyzed gene expression of insulin-like growth factor 2 (Igf2), H19, Igf2 receptor (Igf2r), and miR-483 and their DNA methylation status using real-time quantitative PCR, Western blot, and pyrosequencing. The results showed that when compared with the in vivo group, the body weight of IVF mice was significantly higher at birth, but lower at 3 wk; in addition, gene expression of Igf2 was significantly up-regulated, with down-regulated expression of H19 and miR-483 in both liver and skeletal muscle. At the same time, there were significant differences in the DNA methylation rates of Igf2/H19 differentially methylated regions (DMRs) and the IGF2 protein expression between the two groups. In the IVF treatment group, the differences in growth and expression disappeared at 10 wk. However, at 1.5 yr of age, aberrant expressions of Igf2/H19, Igf2r, and miR-483 and changes in DNA methylation rates in the liver or skeletal muscle were again observed in IVF mice. Our results indicate that IVF causes alterations in mouse growth during the postnatal periods that may be associated with alterations in Igf2/H19 expression and likely involve the regulation of miR-483 and the methylation status of Igf2/H19 DMRs.
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TL;DR: This review will summarize the available evidence on the short-term and long-term health outcomes of ART singletons, as multiple pregnancies after multiple embryos transfer, are associated with low birth weight and preterm delivery, which can separately increase risk of adverse postnatal outcomes, and impact long- term health.
Abstract: Concerns have been raised about the health and development of children conceived by assisted reproductive technologies (ART) since 1978. Controversially, ART has been linked with adverse obstetric and perinatal outcomes, an increased risk of birth defects, cancers, and growth and development disorders. Emerging evidence suggests that ART treatment may also predispose individuals to an increased risk of chronic ageing related diseases such as obesity, type 2 diabetes and cardiovascular disease. This review will summarize the available evidence on the short-term and long-term health outcomes of ART singletons, as multiple pregnancies after multiple embryos transfer, are associated with low birth weight and preterm delivery, which can separately increase risk of adverse postnatal outcomes, and impact long-term health. We will also examine the potential factors that may contribute to these health risks, and discuss underlying mechanisms, including epigenetic changes that may occur during the preimplantation period and reprogram development in utero, and adult health, later in life. Lastly, this review will consider the future directions with the view to optimize the long-term health of ART children.
108 citations
TL;DR: Integrated molecular network modelling revealed differential DNA methylation and miRNA expression changes occur in skeletal muscle in response to chronic exercise training that are most pronounced with endurance training and topographically associated with functional metabolic and microvascular plasticity relevant to diabetes rehabilitation.
Abstract: Epigenomic regulation of the transcriptome by DNA methylation and posttranscriptional gene silencing by miRNAs are potential environmental modulators of skeletal muscle plasticity to chronic exercise in healthy and diseased populations. We utilized transcriptome networks to connect exercise-induced differential methylation and miRNA with functional skeletal muscle plasticity. Biopsies of the vastus lateralis were collected from middle-aged Polynesian men and women with morbid obesity (44 kg/m2 ± 10) and Type 2 diabetes before and following 16 wk of resistance (n = 9) or endurance training (n = 8). Longitudinal transcriptome, methylome, and microRNA (miRNA) responses were obtained via microarray, filtered by novel effect-size based false discovery rate probe selection preceding bioinformatic interrogation. Metabolic and microvascular transcriptome topology dominated the network landscape following endurance exercise. Lipid and glucose metabolism modules were connected to: microRNA (miR)-29a; promoter region hypomethylation of nuclear receptor factor (NRF1) and fatty acid transporter (SLC27A4), and hypermethylation of fatty acid synthase, and to exon hypomethylation of 6-phosphofructo-2-kinase and Ser/Thr protein kinase. Directional change in the endurance networks was validated by lower intramyocellular lipid, increased capillarity, GLUT4, hexokinase, and mitochondrial enzyme activity and proteome. Resistance training also lowered lipid and increased enzyme activity and caused GLUT4 promoter hypomethylation; however, training was inconsequential to GLUT4, capillarity, and metabolic transcriptome. miR-195 connected to negative regulation of vascular development. To conclude, integrated molecular network modelling revealed differential DNA methylation and miRNA expression changes occur in skeletal muscle in response to chronic exercise training that are most pronounced with endurance training and topographically associated with functional metabolic and microvascular plasticity relevant to diabetes rehabilitation.
92 citations
Additional excerpts
...1 (50) KIAA1191, RAD23B development of blood vessel (RAD23B) miR-487 (miR-487b3p; AUCGUAC) 0....
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TL;DR: If it could be confirmed that the type of culture medium used does indeed influence phenotypic characteristics of children born after IVF, it would underline the importance of monitoring the health of IVF children in relation to aspects of the laboratory techniques used during embryo culture.
Abstract: Study question Do culture media influence birthweight of children born after IVF? Summary answer Some studies have observed a significant effect of culture media on birthweight, while others have not, but since most studies compared different culture media, conventional meta-analysis was not possible. What is known already Animal studies suggest that in vitro culture of embryos can have a significant effect on the birthweight of offspring when compared with in vivo developed embryos. The type of culture medium (or certain components of the medium) used is one of the causal factors. Study design, size, duration We reviewed all available literature reporting on a relation between culture medium and birthweight in human studies and a selection of animal studies. Participants/materials, setting, methods An extensive literature search on Pubmed and Medline was performed with relevant search criteria relating to IVF, birthweight and culture medium. Main results and the role of chance Eleven studies reporting on a relationship between culture medium and birthweight in human were included in this review. Five of these found significant differences in birthweight when offspring born after culture in different culture media were compared. The remaining studies did not find differences in birthweight after changing culture medium. Limitations, reasons for caution The number of human studies is limited and different culture media with different compositions are compared which makes a comparison between the studies difficult, if not impossible. Furthermore, most study designs were retrospective with consecutive use of different culture media and limited sample sizes, which makes bias of the results likely. Wider implications of the findings If it could be confirmed that the type of culture medium used does indeed influence phenotypic characteristics (such as birthweight) of children born after IVF, it would underline the importance of monitoring the health of IVF children in relation to aspects of the laboratory techniques used during embryo culture. Study funding/competing interests No funding was applicable to this study. No conflict of interest is declared.
84 citations
Cites methods from "In Vitro Fertilization Alters Growt..."
...The samecomparisonofCook (CookK-SICM, n 1⁄4 974) andMedicult (Medicult embryo Assist, n 1⁄4 351) was also evaluated in a recent retrospective study published by Lemmen et al. (2014). The culture media were used over a consecutive period of time and during the study period, the time of embryo transfer was changed from transfer at Day 2 to transfer at Day 3....
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TL;DR: Key findings include evidence that birthweight is not a reliable marker of fetal stress, and that increases in embryo manipulation result in more deviant fetal growth curves.
Abstract: BACKGROUND The number of children conceived using assisted reproductive technologies (ART) has reached >5 million worldwide and continues to increase. Although the great majority of ART children are healthy, many reports suggest a forthcoming risk of metabolic complications, which is further supported by the Developmental Origins of Health and Disease hypothesis of suboptimal embryo/fetal conditions predisposing adult cardiometabolic pathologies. Accumulating evidence suggests that fetal and placental growth kinetics are important features predicting post-natal health, but the relationship between ART and intrauterine growth has not been systematically reviewed. METHODS Relevant studies describing fetoplacental intrauterine phenotypes of concepti generated by in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI) and somatic cell nuclear transfer (SCNT) in the mouse, bovine and human were comprehensively researched using PubMed and Google Scholar. Intrauterine growth plots were created from tabular formatted data available in selected reports. RESULTS ART pregnancies display minor but noticeable alterations in fetal and placental growth curves across mammalian species. In all species, there is evidence of fetal growth restriction in the earlier stages of pregnancy, followed by significant increases in placental size and accelerated fetal growth toward the end of gestation. However, there is a species-specific effect of ART on birthweights, that additionally vary in a culture condition-, strain-, and/or stage at transfer-specific manner. We discuss the potential mechanisms that underlie these changes, and how they are affected by specific components of ART procedures. CONCLUSIONS ART may promote measurable alterations to intrauterine growth trajectory and placental function. Key findings include evidence that birthweight is not a reliable marker of fetal stress, and that increases in embryo manipulation result in more deviant fetal growth curves. Because growth kinetics in early life are particularly relevant to adult metabolic physiology, we advise more rigorous assessment of fetal growth and placental function in human ART pregnancies, as well as continued follow-up of ART offspring throughout post-natal life. Finally, strategies to minimize embryo manipulations should be adopted whenever possible.
79 citations
Cites background from "In Vitro Fertilization Alters Growt..."
...A different study showed increased birthweight in IVF mouse concepti following transfer of 2-cell IVF C57Bl/6J embryos previously fertilized and cultured 24 h in human tubal fluid (HTF) (Le et al., 2013)....
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TL;DR: Two clinically modifiable factors (embryo culture in 5 vs 20% oxygen tension and fresh vs frozen embryo transfer) are associated with global placental methylation differences and males appear more vulnerable to such treatment-related global changes in DNA methylation than do females.
Abstract: We analyzed placental DNA methylation levels at repeated sequences (LINE1 elements) and all CCGG sites (the LUMA assay) to study the effect of modifiable clinical or laboratory procedures involved in in vitro fertilization. We included four potential modifiable factors: oxygen tension during embryo culture, fresh embryo transfer vs frozen embryo transfer, intracytoplasmic sperm injection (ICSI) vs conventional insemination or day 3 embryo transfer vs day 5 embryo transfer. Global methylation levels differed between placentas from natural conceptions compared to placentas conceived by IVF. Placentas from embryos cultured at 20% oxygen showed significant differences in LINE1 methylation compared to in vivo conceptions, while those from embryos cultured at 5% oxygen, did not have significant differences. In addition, placentas from fresh embryo transfer had significantly different LINE1 methylation compared to placentas from in vivo conceptions, while embryos resulting from frozen embryos were not significantly different from controls. On sex-stratified analysis, only males had significant methylation differences at LINE1 elements stratified for the modifiable factors. As expected, LINE1 methylation was significantly different between males and females in the control population. However, we did not observe sex-specific differences in the IVF group. We validated this sex-specific observation in an additional cohort and in opposite sex IVF twins. We show that two clinically modifiable factors (embryo culture in 5 vs 20% oxygen tension and fresh vs frozen embryo transfer) are associated with global placental methylation differences. Interestingly, males appear more vulnerable to such treatment-related global changes in DNA methylation than do females.
79 citations
References
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TL;DR: It is shown that individuals who were prenatally exposed to famine during the Dutch Hunger Winter in 1944–45 had, 6 decades later, less DNA methylation of the imprinted IGF2 gene compared with their unexposed, same-sex siblings.
Abstract: Extensive epidemiologic studies have suggested that adult disease risk is associated with adverse environmental conditions early in development. Although the mechanisms behind these relationships are unclear, an involvement of epigenetic dysregulation has been hypothesized. Here we show that individuals who were prenatally exposed to famine during the Dutch Hunger Winter in 1944-45 had, 6 decades later, less DNA methylation of the imprinted IGF2 gene compared with their unexposed, same-sex siblings. The association was specific for periconceptional exposure, reinforcing that very early mammalian development is a crucial period for establishing and maintaining epigenetic marks. These data are the first to contribute empirical support for the hypothesis that early-life environmental conditions can cause epigenetic changes in humans that persist throughout life.
2,723 citations
"In Vitro Fertilization Alters Growt..." refers background in this paper
...In human, early-life environmental conditions also can cause epigenetic changes that persist throughout life [22]....
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TL;DR: MethPrimer, based on Primer 3, is a program for designing PCR primers for methylation mapping that takes a DNA sequence as its input and searches the sequence for potential CpG islands, and picks primers around the predicted C pG islands or around regions specified by users.
Abstract: Motivation: DNA methylation is an epigenetic mechanism of gene regulation. Bisulfite- conversion-based PCR methods, such as bisulfite sequencing PCR (BSP) and methylation specific PCR (MSP), remain the most commonly used techniques for methylation mapping. Existing primer design programs developed for standard PCR cannot handle primer design for bisulfite-conversion-based PCRs due to changes in DNA sequence context caused by bisulfite treatment and many special constraints both on the primers and the region to be amplified for such experiments. Therefore, the present study was designed to develop a program for such applications. Results: MethPrimer, based on Primer3, is a program for designing PCR primers for methylation mapping. It first takes a DNA sequence as its input and searches the sequence for potential CpG islands. Primers are then picked around the predicted CpG islands or around regions specified by users. MethPrimer can design primers for BSP and MSP. Results of primer selection are delivered through a web browser in text and in graphic view. Availability: MethPrimer is freely accessible at the following Web address http://itsa.ucsf.edu/∼urolab/methprimer
2,378 citations
"In Vitro Fertilization Alters Growt..." refers methods in this paper
...The MethPrimer software [32] was used to identify CpG islands and to design primers for the H19 DMR (C57BL no....
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TL;DR: This work merges many of the available yeast protein-abundance datasets, using the resulting larger 'meta-dataset' to find correlations between protein and mRNA expression, both globally and within smaller categories.
Abstract: Attempts to correlate protein abundance with mRNA expression levels have had variable success. We review the results of these comparisons, focusing on yeast. In the process, we survey experimental techniques for determining protein abundance, principally two-dimensional gel electrophoresis and mass-spectrometry. We also merge many of the available yeast protein-abundance datasets, using the resulting larger 'meta-dataset' to find correlations between protein and mRNA expression, both globally and within smaller categories.
1,812 citations
"In Vitro Fertilization Alters Growt..." refers background in this paper
...mechanisms involved in turning mRNA into protein that make it difficult to compute protein concentrations from mRNA [47]....
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TL;DR: In vitro fertilization patients should be advised of the increased risk for adverse perinatal outcomes and should not only manage these pregnancies as high risk but also avoid iatrogenic harm caused by elective preterm labor induction or cesarean.
1,081 citations
"In Vitro Fertilization Alters Growt..." refers background in this paper
...In addition to the slight increased risk of congenital malformations, neurodevelopmental delays, and imprinting disorders, there is a 2–4-fold higher incidence of low birth weight (LBW) when compared with naturally conceived newborns, thus representing yet another abnormality in IVF offspring [2–4]....
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...The majority of human studies have shown that the birth weight of IVF-conceived newborns is decreased when compared to those conceived naturally [2–4]....
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TL;DR: Singleton pregnancies from assisted reproduction have a significantly worse perinatal outcome than non-assisted singleton pregnancies, but this is less so for twin pregnancies.
Abstract: Objective To compare the perinatal outcome of singleton and twin pregnancies between natural and assisted conceptions. Design Systematic review of controlled studies published 1985-2002. Studies reviewed 25 studies were included of which 17 had matched and 8 had non-matched controls. Main outcome measures Very preterm birth, preterm birth, very low birth weight, low birth weight, small for gestational age, caesarean section, admission to neonatal intensive care unit, and perinatal mortality. Results For singletons, studies with matched controls indicated a relative risk of 3.27 (95% confidence interval 2.03 to 5.28) for very preterm ( < 32 weeks) and 2.04 (1.80 to 2.32) for preterm ( < 37 weeks) birth in pregnancies after assisted conception. Relative risks were 3.00 (2.07 to 4.36) for very low birth weight ( < 1500 g), 1.70 (1.50 to 1.92) for low birth weight ( < 2500 g), 1.40 (1.15 to 1.71) for small for gestational age, 1.54 (1.44 to 1.66) for caesarean section, 1.27 (1.16 to 1.40) for admission to a neonatal intensive care unit, and 1.68 (1.11 to 2.55) for perinatal mortality. Results of the non-matched studies were similar. In matched studies of twin gestations, relative risks were 0.95 (0.78 to 1.15) for very preterm birth, 1.07 (1.02 to 1.13) for preterm birth, 0.89 (0.74 to 1.07) for very low birth weight, 1.03 (0.99 to 1.08) for low birth weight, 1.27 (0.97 to 1.65) for small for gestational age, 1.21 (1.11 to 1.32) for caesarean section, 1.05 (1.01 to 1.09) for admission to a neonatal intensive care unit, and 0.58 (0.44 to 0.77) for perinatal mortality. The non-matched studies mostly showed similar trends. Conclusions Singleton pregnancies from assisted reproduction have a significantly worse perinatal outcome than non-assisted singleton pregnancies, but this is less so for twin pregnancies. In twin pregnancies, perinatal mortality is about 40% lower after assisted compared with natural conception.
1,038 citations
"In Vitro Fertilization Alters Growt..." refers background in this paper
...In addition to the slight increased risk of congenital malformations, neurodevelopmental delays, and imprinting disorders, there is a 2–4-fold higher incidence of low birth weight (LBW) when compared with naturally conceived newborns, thus representing yet another abnormality in IVF offspring [2–4]....
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...The majority of human studies have shown that the birth weight of IVF-conceived newborns is decreased when compared to those conceived naturally [2–4]....
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