Chia Lin Chang

Site-specific endometrial injury improves implantation and pregnancy in patients with repeated implantation failures

BackgroundTo test whether a site-specific hysteroscopic biopsy-induced injury in the endometrium during the controlled ovarian hyperstimulation cycle improves subsequent embryo implantation in patients with repeated implantation failure, a total of 30 patients who have had good responses to controlled ovulation stimulation but have failed to achieve pregnancy after two or more transfers of good-quality embryos were recruited in this prospective study.MethodsA single, site-specific hysteroscopic biopsy-induced injury was generated on the posterior endometrium at midline 10-15 mm from the fundus during the D4-D7 period of the ongoing controlled ovarian hyperstimulation cycle in six patients.ResultsPatients received endometrial biopsy protocol achieved a pregnancy rate of 100%. By contrast, only 46% of patients with similar clinical characteristics (N = 24) achieved pregnancy without the hysteroscopic biopsy-induced endometrium injury (p < 0.05).ConclusionsOur proof-of-concept study demonstrates that a site-specific hysteroscopic endometrium injury performed during the ongoing in vitro fertilization (IVF) cycle, instead of injuries received during prior cycles, significantly improves clinical outcomes in patients with repeated implantation failure.

Circulating Irisin and Glucose-Dependent Insulinotropic Peptide Are Associated With the Development of Polycystic Ovary Syndrome

CONTEXT Polycystic ovary syndrome (PCOS) is characterized by oligo- or anovulation, polycystic ovary, and/or hyperandrogenism. In addition, many PCOS patients present with dyslipidemia, insulin resistance, and obesity. Due to the complexity of this disorder, the causes of PCOS remain to be identified. OBJECTIVES Because many PCOS patients have a propensity to develop dyslipidemia, we hypothesized that the brown adipose-differentiation factor, irisin, and the glucose-dependent insulinotropic peptide (GIP) play a role in the development of PCOS. DESIGN AND SETTING Serum hormone levels in 202 PCOS patients and 47 healthy women were investigated. PATIENTS OR OTHER PARTICIPANTS Patients were stratified based on the presence/absence of metabolic syndrome risk factors, as defined by the National Cholesterol Education Programs Adult Treatment Panel III report (ATPIII [+] and ATPIII [-]), or body mass index (healthy-weight and overweight). MAIN OUTCOME MEASURES We measured serum irisin, GIP, LH, anti-Mullerian hormone (AMH), and androgens as well as metabolic indices including homeostasis model assessment-insulin resistance, Matsudas sensitivity index, and quantitative insulin-sensitivity check index. RESULTS PCOS patients exhibited hyperandrogenism, dyslipidemia, and hyperinsulinism, as well as elevated LH and AMH levels. In addition, fasting irisin level (P < .001) and glucose-induced GIP response (P = .013) in PCOS patients were significantly elevated as compared to those of control women. Remarkably, levels of fasting irisin and glucose-induced GIP response remained significantly elevated in ATP III [-] PCOS and healthy-weight PCOS patients when compared to matched controls. Analysis of the effect size indicated that both fasting irisin and glucose-induced GIP response are significant risk factors for PCOS with odds ratios of 6.63 and 4.21, respectively. CONCLUSION Although there is as yet no evidence for a causal link between irisin and/or GIP and PCOS, it is conceivable that irisin and GIP might contribute to the development of PCOS and may also represent novel PCOS biomarkers.

GPCR genes are preferentially retained after whole genome duplication.

One of the most interesting questions in biology is whether certain pathways have been favored during evolution, and if so, what properties could cause such a preference. Due to the lack of experimental evidence, whether select gene families have been preferentially retained over time after duplication in metazoan organisms remains unclear. Here, by syntenic mapping of nonchemosensory G protein-coupled receptor genes (nGPCRs which represent half the receptome for transmembrane signaling) in the vertebrate genomes, we found that, as opposed to the 8–15% retention rate for whole genome duplication (WGD)-derived gene duplicates in the entire genome of pufferfish, greater than 27.8% of WGD-derived nGPCRs which interact with a nonpeptide ligand were retained after WGD in pufferfish Tetraodon nigroviridis. In addition, we show that concurrent duplication of cognate ligand genes by WGD could impose selection of nGPCRs that interact with a polypeptide ligand. Against less than 2.25% probability for parallel retention of a pair of WGD-derived ligands and a pair of cognate receptor duplicates, we found a more than 8.9% retention of WGD-derived ligand-nGPCR pairs–threefold greater than one would surmise. These results demonstrate that gene retention is not uniform after WGD in vertebrates, and suggest a Darwinian selection of GPCR-mediated intercellular communication in metazoan organisms.

Adaptive selection of an incretin gene in Eurasian populations

Diversities in human physiology have been partially shaped by adaptation to natural environments and changing cultures. Recent genomic analyses have revealed single nucleotide polymorphisms (SNPs) that are associated with adaptations in immune responses, obvious changes in human body forms, or adaptations to extreme climates in select human populations. Here, we report that the human GIP locus was differentially selected among human populations based on the analysis of a nonsynonymous SNP (rs2291725). Comparative and functional analyses showed that the human GIP gene encodes a cryptic glucose-dependent insulinotropic polypeptide (GIP) isoform (GIP55S or GIP55G) that encompasses the SNP and is resistant to serum degradation relative to the known mature GIP peptide. Importantly, we found that GIP55G, which is encoded by the derived allele, exhibits a higher bioactivity compared with GIP55S, which is derived from the ancestral allele. Haplotype structure analysis suggests that the derived allele at rs2291725 arose to dominance in East Asians ∼8100 yr ago due to positive selection. The combined results suggested that rs2291725 represents a functional mutation and may contribute to the population genetics observation. Given that GIP signaling plays a critical role in homeostasis regulation at both the enteroinsular and enteroadipocyte axes, our study highlights the importance of understanding adaptations in energy-balance regulation in the face of the emerging diabetes and obesity epidemics.

Widespread Divergence of the CEACAM/PSG Genes in Vertebrates and Humans Suggests Sensitivity to Selection

In mammals, carcinoembryonic antigen cell adhesion molecules (CEACAMs) and pregnancy-specific glycoproteins (PSGs) play important roles in the regulation of pathogen transmission, tumorigenesis, insulin signaling turnover, and fetal–maternal interactions. However, how these genes evolved and to what extent they diverged in humans remain to be investigated specifically. Based on syntenic mapping of chordate genomes, we reveal that diverging homologs with a prototypic CEACAM architecture–including an extracellular domain with immunoglobulin variable and constant domain-like regions, and an intracellular domain containing ITAM motif–are present from cartilaginous fish to humans, but are absent in sea lamprey, cephalochordate or urochordate. Interestingly, the CEACAM/PSG gene inventory underwent radical divergence in various vertebrate lineages: from zero in avian species to dozens in therian mammals. In addition, analyses of genetic variations in human populations showed the presence of various types of copy number variations (CNVs) at the CEACAM/PSG locus. These copy number polymorphisms have 3–80% frequency in select populations, and encompass single to more than six PSG genes. Furthermore, we found that CEACAM/PSG genes contain a significantly higher density of nonsynonymous single nucleotide polymorphism (SNP) compared to the chromosome average, and many CEACAM/PSG SNPs exhibit high population differentiation. Taken together, our study suggested that CEACAM/PSG genes have had a more dynamic evolutionary history in vertebrates than previously thought. Given that CEACAM/PSGs play important roles in maternal–fetal interaction and pathogen recognition, these data have laid the groundwork for future analysis of adaptive CEACAM/PSG genotype-phenotypic relationships in normal and complicated pregnancies as well as other etiologies.

Regulation of Oocyte and Cumulus Cell Interactions by Intermedin/Adrenomedullin 2

Background: Oocytes are known to secrete factors that regulate the tertiary structure of cumulus cell-enclosed oocyte complexes (COCs). Results: Intermedin (IMD) signaling promotes cumulus cell survival and cell contacts in COCs. Conclusion: Endogenous IMD plays a critical role in coordinating COC development. Significance: The study provided new insight into how the tertiary structure of COCs is maintained during folliculogenesis. Ovarian folliculogenesis has been studied as a model of hormonal regulation of development and differentiation, cell death, and cell-cell communication. In addition to gonadotropins from the pituitary and follicular paracrine factors, oocyte secreted factors have been shown to play critical roles in the regulation of follicular cell functions. Except for the well characterized BMP family proteins, including GDF9 and BMP15, oocytes are known to secrete oocyte secreted factors that are important for the regulation of cumulus cell survival and the maintenance of tertiary structure of cumulus cell-enclosed oocyte complexes (COCs). Based on genomic screening and studies of COCs cultured in vitro, we showed that intermedin (IMD)/adrenomedullin 2 (ADM2) is a novel oocyte-derived ligand important for the regulation of cell interactions in COCs that functions, in part, by suppressing cumulus cell apoptosis. Consistently, we showed that suppression of IMD/ADM2 signaling in growing rat ovaries in vivo leads to oocyte atresia and aberrant cell cycle progression in follicular cells. Together, our studies indicated that mammalian oocytes deploy a G protein-coupled receptor ligand to coordinate normal interactions of oocytes and cumulus cells and provided a better understanding of how the tertiary structure of a COC is maintained as follicles undergo exponential growth during the late stages of folliculogenesis.

Identification of Metabolic Modifiers That Underlie Phenotypic Variations in Energy-Balance Regulation

OBJECTIVE Although recent studies have shown that human genomes contain hundreds of loci that exhibit signatures of positive selection, variants that are associated with adaptation in energy-balance regulation remain elusive. We reasoned that the difficulty in identifying such variants could be due to heterogeneity in selection pressure and that an integrative approach that incorporated experiment-based evidence and population genetics-based statistical judgments would be needed to reveal important metabolic modifiers in humans. RESEARCH DESIGN AND METHODS To identify common metabolic modifiers that underlie phenotypic variation in diabetes-associated or obesity-associated traits in humans, or both, we screened 207 candidate loci for regulatory single nucleotide polymorphisms (SNPs) that exhibited evidence of gene–environmental interactions. RESULTS Three SNPs (rs3895874, rs3848460, and rs937301) at the 5′ gene region of human GIP were identified as prime metabolic-modifier candidates at the enteroinsular axis. Functional studies have shown that GIP promoter reporters carrying derived alleles of these three SNPs (haplotype GIP−1920A) have significantly lower transcriptional activities than those with ancestral alleles at corresponding positions (haplotype GIP−1920G). Consistently, studies of pregnant women who have undergone a screening test for gestational diabetes have shown that patients with a homozygous GIP−1920A/A genotype have significantly lower serum concentrations of glucose-dependent insulinotropic polypeptide (GIP) than those carrying an ancestral GIP−1920G haplotype. After controlling for a GIPR variation, we showed that serum glucose concentrations of patients carrying GIP−1920A/A homozygotes are significantly higher than that of those carrying an ancestral GIP−1920G haplotype (odds ratio 3.53). CONCLUSIONS Our proof-of-concept study indicates that common regulatory GIP variants impart a difference in GIP and glucose metabolism. The study also provides a rare example that identified the common variant-common phenotypic variation pattern based on evidence of moderate gene–environmental interactions.

GENOME-WIDE DETECTION OF UNIPARENTAL DISOMY IN A FETUS WITH INTRAUTERINE GROWTH RESTRICTION USING GENOTYPING MICROARRAYS

OBJECTIVE To present the clinical and molecular features of a fetus with confined trisomy 16 mosaicism with maternal uniparental disomy (UPD), using various prenatal diagnostic techniques. MATERIALS AND METHODS Chromosomal karyotyping was performed on samples of chorionic villi, amniotic fluid cells, amniotic membrane, umbilical cord, fetal skin, and placenta from a fetus with elevated nuchal translucency. Polymorphic short tandem repeat markers and Affymetrix single nucleotide polymorphism (SNP) mapping chips were used for molecular analyses. RESULTS Karyotypes from chorionic villi and amniocytes showed 47,XX,+16 and 46,XX, respectively. Short tandem repeat markers on chromosome 16 suggested maternal UPD for chromosome 16. Affymetrix 10K SNP mapping chips were used to simultaneously confirm the difference in karyotypes between the placenta and amniocytes and to diagnose UPD for chromosome 16. Fetal ultrasonography and magnetic resonance imaging identified severe intrauterine growth restriction (IUGR). Autopsy revealed IUGR, incomplete lobulation of bilateral lungs, and malrotation of the intestines. The karyotypes of umbilical cord, fetal skin and amniotic membrane were 46,XX, and the trisomy 16 karyotype appeared to be confined to the placenta. CONCLUSION UPD should be investigated as a possible etiology in all cases of unexplained IUGR. SNP microarrays can be useful for confirming this diagnosis.

Adaptive human CDKAL1 variants underlie hormonal response variations at the enteroinsular axis.

Recent analyses have identified positively selected loci that explain differences in immune responses, body forms, and adaptations to extreme climates, but variants that describe adaptations in energy-balance regulation remain underexplored. To identify variants that confer adaptations in energy-balance regulation, we explored the evolutionary history and functional associations of candidate variants in 207 genes. We screened single nucleotide polymorphisms in genes that had been associated with energy-balance regulation for unusual genetic patterns in human populations, followed by studying associations among selected variants and serum levels of GIP, insulin, and C-peptide in pregnant women after an oral glucose tolerance test. Our analysis indicated that 5′ variants in CDKAL1, CYB5R4, GAD2, and PPARG are marked with statistically significant signals of gene–environment interactions. Importantly, studies of serum hormone levels showed that variants in CDKAL1 are associated with glucose-induced GIP and insulin responses (p<0.05). On the other hand, a GAD2 variant exhibited a significant association with glucose-induced C-peptide response. In addition, simulation analysis indicated that a type 2 diabetes risk variant in CDKAL1 (rs7754840) was selected in East Asians ∼6,900 years ago. Taken together, these data indicated that variants in CDKAL1 and GAD2 were targets of prior environmental selection. Because the selection of the CDKAL1 variant overlapped with the selection of a cluster of GIP variants in the same population ∼11,800 to 2,000 years ago, we speculate that these regulatory genes at the human enteroinsular axis could be highly responsive to environmental selection in recent human history.

Transcutaneous electrical acupoint stimulation (TEAS) treatment improves pregnancy rate and implantation rate in patients with implantation failure

OBJECTIVE Although major advances have greatly improved the outcomes of assisted reproductive technology in the last two cascades, there remains significant difficulty in achieving pregnancy for many patients even after repeated attempts of IVF. Interestingly, recent studies have shown that transcutaneous electrical acupoint stimulation (TEAS) can improve the reproductive outcomes of select IVF patients. To determine the utility of TEAS in improving IVF outcomes in patients with a history of implantation failure, we conducted a retrospective study of clinical outcomes of women, who had a prior history of unsuccessful pregnancy outcome after IVF-embryo transfer (IVF-ET), following TEAS treatment. MATERIALS AND METHODS A total of 25 patients, who had failed to conceive after multiple IVF cycles in which good embryos were transferred, received noninvasive low frequency TEAS treatment prior to and during an IVF-ET cycle. The clinical outcomes, including biochemical pregnancy rate, clinical pregnancy rate and implantation rate, were compared to those of prior cycles which received only standard IVF treatment. RESULTS Analysis of reproductive outcomes showed that implantation rate and clinical pregnancy rate increased significantly in IVF cycles that included the TEAS treatment when compared to prior cycles that received only the standard IVF treatment in this cohort of patients. CONCLUSIONS This surprising finding indicated that TEAS treatment is a promising technique to improve reproductive outcomes in difficult cases of IVF-ET. Because TEAS treatment is noninvasive and has high reproducibility, and can be applied with limited training, further refinement of this procedure would not only substantiate the beneficial effects of TEAS, but also allow the technique to be more effective and reproducible.