BACKGROUND Nickel (Ni) may accumulate in the human body and has biological toxicity and carcinogenicity. Ni has an extensive impact on the health of pregnant women and fetuses during gestation. AIM To evaluate Ni exposure in pregnant women in Kunming, Yunnan Province, China; to describe the distribution of Ni in the maternal-fetal system and placental barrier function; and to investigate the effect of Ni exposure on fetal health in mothers with pregnancy complications. METHODS Seventy-two pregnant women were selected using a case-control design. The women were divided into two groups: The control group (no disease; n = 29) and the disease group [gestational diabetes (GDM), hypertensive disorder complicating pregnancy (HDCP), or both; n = 43]. The pregnant women in the disease group were further divided as follows: 14 cases with GDM (GDM group), 13 cases with HDCP (HDCP group) and 16 cases with both GDM and HDCP (disease combination group). Basic information on the pregnant women was collected by questionnaire survey. Maternal blood, placenta blood and cord blood were collected immediately after delivery. The Ni content in paired samples was determined using inductively coupled plasma mass spectrometry. RESULTS Compared to the control group, age was higher and body mass index was greater in pregnant women in the disease groups (28.14 ± 2.54 vs 28.42 ± 13.89, P < 0.05; 25.90 ± 3.86 vs 31.49 ± 5.30, P < 0.05). The birth weights of newborns in the HDCP group and the control group were significantly different (2.52 ± 0.74 vs 3.18 ± 0.41, P < 0.05). The content of Ni in umbilical cord blood in the entire disease group was higher than that in the control group (0.10 ± 0.16 vs 0.05 ± 0.07, P < 0.05). CONCLUSION In the maternal-fetal system of women with pregnancy complications, the barrier effect of the placenta against Ni is weakened, thus affecting healthy growth of the fetus in the uterus.

Purpose As two of the most severe and common medical disorders during pregnancy, gestational diabetes mellitus (GDM) and hypertensive disorder complicating pregnancy (HDCP) cause adverse effects on placental barrier function and thus may lead to a high risk of intrauterine exposure to toxic metals from mother to fetus. This study investigates the impact of the placental barrier on the transfer of cadmium (Cd) from mother to fetus and the relationship between pregnancy complications. Methods A total of 107 pairs of samples were collected in Kunming, China; 29 were from healthy pregnant women, and 78 were from patients with pregnancy complications. Cd was measured in each mother’s placenta and maternal and umbilical cord blood. The expressions of MT and Cd-MT complex in blood and placental tissue samples were determined by enzyme-linked immunosorbent assay (ELISA). Results The cesarean section rate in the whole pathological group (60.7%) was higher than that in the normal group (20.7%), and the ratio of the effective barrier (ratio of maternal blood to umbilical cord blood>1) in the pathological group (74%) was lower than that in the normal group (79%). In addition, the proportion of practical placental barriers in women aged 20–25 years was 83.3%, 76.3% in women aged 26–30 years, 74.3% in women aged 31–35 years, 70% in women aged 36–40 years, and 71% in women aged 40–45 years. The Cd content in the placenta of the three pathological groups was significantly higher than that in maternal and umbilical cord blood ( P <0.05), and the distribution of Cd was the same as that in the normal group. However, there was no significant difference between maternal and umbilical cord blood Cd concentrations in the pathological group. The Cd concentration in the normal group’s maternal blood was significantly higher than that in cord blood ( P <0.05). In addition, the expression levels of both metallothionein (MT) and Cd-MT complex in placenta is much higher than in maternal and umbilical blood, and which in normal group are significantly higher than those in pathological group. Conclusion Both mothers and fetuses are at increased health risk for pregnancy disorders when maternal age, BMI, or body weight increases. Increased maternal age increases the likelihood of Cd transfer from the mother to the fetus. Pregnancy complications may induce lower expression of MT, thus reducing the Cd-MT complex in the placenta, weakening the placental barrier, and increasing the risk of Cd transfer and exposure to the fetus.

Purpose To evaluate the levels and differences of trace elements (Zn, Cu, Fe, Mn, Ni, Cr) in maternal-fetal systems (maternal blood, placenta, umbilical cord blood) of different healthy states. To analyze the influence of pregnancy disease on the distribution of trace elements between the mother and fetus. Methods Maternal, placental and umbilical blood samples were collected from 140 parturients (60 in the normal group, 40 in the HDCP group and 40 in the GDM group). The contents of trace elements in paired samples were determined by inductively coupled plasma–mass spectrometry (ICP–MS). SPSS software was used to analyze the differences in trace element levels in matched samples of each group. Results The distribution of Fe content in the normal group was as follows: umbilical cord blood > maternal blood > placenta (p < 0.001). Although the distribution characteristics of Fe in the HDCP group and GDM group were the same as those in the normal group, there was no significant difference in Fe content between maternal and umbilical cord blood (p > 0.05). In addition, the levels of Fe in maternal blood, placental blood and umbilical cord blood in the HDCP group were higher than those in the normal control group (p < 0.05). The distribution characteristics of Mn content in the HDCP group and GDM group were placenta > umbilical cord blood > maternal blood. There were significant differences in Mn content between the placenta and maternal and umbilical cord blood (p < 0.001). The distribution characteristics of Mn content in the HDCP group and GDM group were placenta > umbilical cord blood > maternal blood. There were significant differences in the Mn content between the placenta, maternal blood and umbilical blood in the HDCP group (p < 0.05). Only the Mn content between the placenta and maternal blood was significantly different in the GDM group (p < 0.001). In addition, the content of Cr in the placenta and umbilical blood of the HDCP group was higher than that of the normal group (p < 0.05). The content of Ni in the cord blood of the HDCP group and GDM group was higher than that of the normal group (p < 0.05). Conclusion HDCP and GDM affect the transport of Fe, Ni and Cr from the placenta to the fetus. In addition, the occurrence of GDM also changes the distribution of Fe and Mn in the maternal-fetal system (maternal blood, placenta and umbilical cord blood).

Extraembryonic endoderm stem (XEN) cell lines can be derived and maintained in vitro and reflect the primitive endoderm cell lineage. SOX17 is thought to be required for the derivation and maintenance of mouse XEN cell lines. Here we have re-evaluated this requirement for SOX17. We derived multiple SOX17-deficient XEN cell lines from preimplantation embryos of a SOX17-Cre knockout strain and chemically converted multiple SOX17-deficient embryonic stem cell lines into XEN cell lines by transient culturing with retinoic acid and Activin A. We confirmed the XEN profile of SOX17-deficient cell lines by immunofluorescence with various markers, by NanoString gene expression analyses, and by their contribution to the extraembryonic endoderm of chimeric embryos produced by injecting these cells into blastocysts. Thus, SOX17 is not required for the derivation and maintenance of XEN cell lines.