Objective To systematically evaluate the correlation between vitamin D deficiency in early pregnancy and the outcome of preterm birth.Method PubMed,Embase,the Cochrane Library,Web of Science,Ebsco,CBM,CNKI and Wanfang Data databases were searched to collect cohort studies and case-control studies on the correlation between vitamin D deficiency in early pregnancy and preterm birth outcomes,and the retrieval time was from the establishment of the database to June 2019.Two researchers independently reviewed the literature,extracted the data and evaluated the risk of bias in the included studies.RevMan 5.3 software was used for Meta analysis.Result A total of 6 cohort studies and 3 nested case-control studies were included.A total of 30 891 newborns were included,including 1 912 premature infants.3 Chinese articles and 6 English articles were reviewed including three studies from China,three from North America,two from Europe and one from Australia.The diagnostic criteria for vitamin D deficiency and preterm birth were similar in these studies.After adjusting for age,race and other confounding factors,Meta-analysis results showed that vitamin D deficiency in early pregnancy did not increase the risk of preterm birth (OR =1.04,95％ CI 0.90 ～ 1.20,P =0.63).Subgroup analysis were conducted according to the study type,measurement method and regional population,and the results were consistent with the overall results.No significant publication bias was found in the meta-analysis results.Conclusion Current evidence suggests that vitamin D deficiency in early pregnancy has no significant influence on preterm birth.

OBJECTIVES: Long-term treatment of olanzapine, the most widely-prescribed second-generation antipsychotic, remarkably increases the risk of non-alcoholic fatty liver disease (NAFLD), whereas the mechanism for olanzapine-induced NAFLD remains unknown. Excessive hepatic fat accumulation is the basis for the pathogenesis of NAFLD, which results from the disturbance of TG metabolism in the liver. Apolipoprotein A5 (ApoA5) is a key regulator for TG metabolism in vivo that promotes TG accumulation in hepatocytes, thereby resulting in the development of NAFLD. However, there are no data indicating the role of apoA5 in olanzapine-induced NAFLD. Therefore, this study aims to investigate the role of apoA5 in olanzapine-induced NAFLD. METHODS: This study was carried out via animal studies, cell experiment, and ApoA5 gene knockdown experiment. Six-week-old male C57BL/6J mice were randomized into a control group, a low-dose group, and a high-dose group, which were treated by 10% DMSO, 3 mg/(kg·d) olanzapine, and 6 mg/(kg·d) olanzapine, respectively for 8 weeks. The lipid levels in plasma, liver function indexes, and expression levels of ApoA5 were detected. HepG2 cells were treated with 0.1% DMSO (control group), 25 μmol/L olanzapine (low-dose group), 50 μmol/L olanzapine (medium-dose group), and 100 μmol/L olanzapine (high-dose group) for 24 h. HepG2 cells pretreated with 100 μmol/L olanzapine were transfected with siRNA and scrambled siRNA (negative control), respectively. We observed the changes in lipid droplets within liver tissues and cells using oil red O staining and fat deposition in liver tissues using HE staining. The mRNA and protein levels of ApoA5 were determined by real-time PCR and Western blotting, respectively. RESULTS: After intervention with 3 and 6 mg/(kg·d) olanzapine for 8 weeks, there was no significant difference in body weight among the 3 groups (P>0.05). Olanzapine dose-dependently increased the plasma TG, ALT and AST levels, and reduced plasma ApoA5 levels (all P<0.05), whereas there was no significant difference in plasma cholesterol (HDL-C, LDL-C, and TC) levels among the 3 groups (all P>0.05). Olanzapine dose-dependently up-regulated ApoA5 protein levels in liver tissues (all P<0.05), but there was no significant change in ApoA5 mRNA expression among groups (P>0.05). In the control group, the structure of liver tissues was intact, the morphology of liver cells was regular, and only a few scattered lipid droplets were found in the cells. In the olanzapine-treated group, there was a large amount of lipid deposition in hepatocytes, and cells were balloon-like and filled with lipid droplet vacuoles. The nucleus located at the edge of cell, and the number of lipid droplets was increased significantly, especially in the high-dose group. Likewise, when HepG2 cells were treated with olanzapine for 24 h, the number and size of lipid droplets were significantly elevated in a dose-dependent manner. Moreover, olanzapine dose-dependently up-regulated ApoA5 protein levels in HepG2 cells (all P<0.05), but there was no significant difference in ApoA5 mRNA expression among groups (P>0.05). Compared with the HepG2 cells transfected with scrambled siRNA, the number and size of lipid droplets in HepG2 cells transfected with ApoA5 siRNA were significantly reduced. CONCLUSIONS The short-term intervention of olanzapine does not significantly increase body weight of mice, but it can directly induce hypertriglyceridemia and NAFLD in mice. Olanzapine inhibits hepatic apoA5 secretion but does not affect hepatic apoA5 synthesis, resulting in the pathogenesis of NAFLD. Inhibition of apoA5 secretion plays a key role in the development of olanzapine-related NAFLD, which may serve as an intervention target for this disease.
Animals ; Apolipoprotein A-V/genetics* ; Body Weight ; Dimethyl Sulfoxide/metabolism* ; Liver/metabolism* ; Male ; Mice ; Mice, Inbred C57BL ; Non-alcoholic Fatty Liver Disease/chemically induced* ; Olanzapine/metabolism* ; RNA, Messenger/metabolism* ; RNA, Small Interfering ; Triglycerides