Perinatal Natural History of the Ts1Cje Mouse Model of Down Syndrome: Growth Restriction, Early Mortality, Heart Defects, and Delayed Development.

BACKGROUND: The Ts1Cje model of Down syndrome is of particular interest for perinatal studies because affected males are fertile. This permits affected pups to be carried in wild-type females, which is similar to human pregnancies. Here we describe the early natural history and growth profiles of Ts1Cje embryos and neonates and determine if heart defects are present in this strain. METHODS: Pups were studied either on embryonic (E) day 15.5, or from postnatal (P) day 3 through weaning on P21. PCR amplification targeting the neomycin cassette (present in Ts1Cje) and Sry (present in males) was used to analyze pup genotypes and sex ratios. Body weights and lengths, as well as developmental milestones, were recorded in Ts1Cje mice and compared to their wild-type (WT) littermates. Histological evaluations were performed at E15.5 to investigate the presence or absence of heart defects. Pups were divided into two groups: Ts1Cje-I pups survived past weaning and Ts1Cje-II pups died at some point before P21. RESULTS: Ts1Cje mouse embryos showed expected Mendelian ratios (45.8%, n = 66 for Ts1Cje embryos; 54.2%, n = 78 for WT embryos). Histological analysis revealed the presence of ventricular septal defects (VSDs) in 21% of Ts1Cje E15.5 embryos. After weaning, only 28.2% of pups were Ts1Cje (185 Ts1Cje out of 656 total pups generated), with males predominating (male:female ratio of 1.4:1). Among the recovered dead pups (n = 207), Ts1Cje (63.3%, n = 131, p<0.01) genotype was found significantly more often than WT (36.7%, n = 76). Retrospective analysis of Ts1Cje-II (pre-weaning deceased) pups showed that they were growth restricted compared to Ts1Cje-I pups (post-weaning survivors). Growth restriction correlated with statistically significant delays in achieving several neonatal milestones between P3 and P21 compared to Ts1Cje-I (post-weaning survivors) neonates and WT littermates. CONCLUSIONS: Ts1Cje genotype is not associated with increased early in utero mortality. Cardiac defects, specifically VSDs, are part of the phenotype in this strain. There is increased neonatal mortality in Ts1Cje pups, with sex differences observed. Ts1Cje mice that died in the neonatal period were more likely to be growth restricted and delayed in achieving neonatal developmental milestones.

The fetal brain transcriptome and neonatal behavioral phenotype in the Ts1Cje mouse model of Down syndrome.

Human fetuses with Down syndrome demonstrate abnormal brain growth and reduced neurogenesis. Despite the prenatal onset of the phenotype, most therapeutic trials have been conducted in adults. Here, we present evidence for fetal brain molecular and neonatal behavioral alterations in the Ts1Cje mouse model of Down syndrome. Embryonic day 15.5 brain hemisphere RNA from Ts1Cje embryos (n = 5) and wild type littermates (n = 5) was processed and hybridized to mouse gene 1.0 ST arrays. Bioinformatic analyses were implemented to identify differential gene and pathway regulation during Ts1Cje fetal brain development. In separate experiments, the Fox scale, ultrasonic vocalization and homing tests were used to investigate behavioral deficits in Ts1Cje pups (n = 29) versus WT littermates (n = 64) at postnatal days 3-21. Ts1Cje fetal brains displayed more differentially regulated genes (n = 71) than adult (n = 31) when compared to their age-matched euploid brains. Ts1Cje embryonic brains showed up-regulation of cell cycle markers and down-regulation of the solute-carrier amino acid transporters. Several cellular processes were dysregulated at both stages, including apoptosis, inflammation, Jak/Stat signaling, G-protein signaling, and oxidoreductase activity. In addition, early behavioral deficits in surface righting, cliff aversion, negative geotaxis, forelimb grasp, ultrasonic vocalization, and the homing tests were observed. The Ts1Cje mouse model exhibits abnormal gene expression during fetal brain development, and significant neonatal behavioral deficits in the pre-weaning period. In combination with human studies, this suggests that the Down syndrome phenotype manifests prenatally and provides a rationale for prenatal therapy to improve perinatal brain development and postnatal neurocognition.

Antenatal noninvasive DNA testing: clinical experience and impact.

BACKGROUND: Nearly two decades ago, the discovery of circulating cell-free fetal DNA in maternal blood created a paradigm shift in prenatal testing. Recent advances in DNA sequencing technology have facilitated the rapid translation of DNA-based testing into clinical antenatal care. CONTENT: In this review, we summarize the technical approaches and current clinical applications of noninvasive testing using cell-free DNA in maternal plasma. We discuss the impact of these tests on clinical care, outline proposed integration models, and suggest future directions for the field. SUMMARY: The use of cell-free DNA in maternal blood for the detection of fetal rhesus D antigen status, fetal sex, and common whole chromosomal aneuploidies is now well established, although testing for aneuploidy is still considered screening and not diagnostic. Further advances in technology and bioinformatics may see future clinical applications extend to the noninvasive detection of fetal subchromosomal aneuploidy, single gene disorders, and the entire fetal genome.

Rate of wound complications with enoxaparin use among women at high risk for postpartum thrombosis.

OBJECTIVE: To estimate the rate of wound complications associated with protocol-driven postcesarean enoxaparin thromboprophylaxis. METHODS: After implementing an Institutional Clinical Practice Guideline for postoperative cesarean delivery thromboprophylaxis among at-risk gravid women (older than 35 years of age, body mass index greater than 30 kg/m2, or both), data on all cesarean deliveries over the first 23 months of guideline implementation were extracted and analyzed. Primary (wound hematoma, separation, or dehiscence) and secondary (venous thromboembolism) outcomes were compared in stratified and multivariable models controlling for potential confounders. RESULTS: Over 23 months, 2,509 cesarean deliveries were performed. A total of 1,677 (68%) gravid women met criteria for thromboprophylaxis; 653 received enoxaparin per protocol ("cases"), and, at the discretion of the ordering physician, 1,024 did not (at-risk, protocol-noncompliant "controls"). Cases differed significantly by virtue of maternal age, body mass index, and diabetic status. Univariable analysis subsequently revealed a higher rate of wound separation (6.8% compared with 3.6%, P=.003), rehospitalization (2.1% compared with 0.8%, P=.017) and composite score (8.9% compared with 4.8%, P=.002) among protocol-compliant cases, but no increased risk of wound hematoma (P>.06). In multivariable analysis, adjusted odds ratios continued to reveal an association between enoxaparin use and wound separation (OR 1.66, P=.04) as well as higher composite score (OR 1.69, P=.01). However, among the protocol-noncompliant controls, a nonsignificant increase in the rate of venous thromboembolism occurred. CONCLUSION: In our series, prophylactic enoxaparin use among at-risk gravid women undergoing cesarean delivery was accompanied by an increased risk of wound separation. LEVEL OF EVIDENCE: II.