Recent studies have reported a strong association between gestational diabetes mellitus (GDM) and postpartum depression (PPD), but little is known about the underlying physiological mechanism. In this study, a GDM rat model was used to evaluate the direct effect of GDM on PPD and to explore the mechanism. After parturition, the GDM dams were divided into two groups: blood glucose not recovered group (GH group) and blood glucose recovered group (GL group). Fasting plasma glucose (FPG), cortisol (COR) and serotonin (5-hydroxytryptamine, 5-HT) metabolism were continuously monitored during the lactation period, until postnatal day 21. PPD was evaluated by behavioral tests. At the endpoint, the expression of the key enzymes of Trp metabolic pathway in colon and brain tissues was analyzed by immunohistochemistry and western blot. The microbe composition of colonic contents was determined by 16S rDNA gene sequencing. The results showed that GDM induced postpartum depression-like behavior in rats. The HPA axis hormone did not show the typical stress state of depression, but the level of 5-HT decreased significantly in serum, prefrontal cortex and hippocampus, and the Kyn/Trp ratio increased significantly in serum and prefrontal cortex, implying the switch of the tryptophan (Trp) metabolism from the 5-HT pathway to the kynurenine (Kyn) pathway. The expression of Indoleamine 2,3-dioxygenase (IDO), a key rate-limiting enzyme in Kyn metabolism, was up-regulated in the colon and brain, which was an important reason for this switch. This switch was accelerated by a decrease in the expression of tryptophan hydroxylase (TPH), a key enzyme of the 5-HT production pathway, in the colon. GDM dams displayed significant changes in gut microbiome profiles, which were correlated with depression. The ratio of Firmicutes to Bacteroidetes decreased. Lactobacillus and Bacteroides were negatively correlated with 5-HT level and positively correlated with Kyn level, whereas Clostridium XlVa and Ruminococcus were positively correlated with 5-HT level. These results suggest that GDM disrupts both the Trp pathway and the composition of the gut microbiota, which provide a putative physiological basis for PPD.

This study was designed to identify serum and amniotic fluid (AF) metabolic profile changes in response to gestational diabetes mellitus (GDM) and explore the association with maternal–fetal outcomes. We established the GDM rat models by combining a high-fat diet (HFD) with an injection of low-dose streptozotocin (STZ), detected the fasting plasma glucose (FPG) of pregnant rats in the second and third trimester, and collected AF and fetal rats by cesarean section on gestational day 19 (GD19), as well as measuring the weight and crown–rump length (CRL) of fetal rats. We applied liquid chromatography–tandem mass spectrometry (LC-MS/MS) for the untargeted metabolomics analyses of serum and AF samples and then explored their correlation with maternal–fetal outcomes via the co-occurrence network. The results showed that 91 and 68 metabolites were upregulated and 125 and 78 metabolites were downregulated in serum and AF samples exposed to GDM, respectively. In maternal serum, the obvious alterations emerged in lipids and lipid-like molecules, while there were great changes in carbohydrate and carbohydrate conjugates, followed by amino acids, peptides, and analogs in amniotic fluid. The altered pathways both in serum and AF samples were amino acid, lipid, nucleotide, and vitamin metabolism pathways. In response to GDM, changes in the steroid hormone metabolic pathway occurred in serum, and an altered carbohydrate metabolism pathway was found in AF samples. Among differential metabolites in two kinds of samples, there were 34 common biochemicals shared by serum and AF samples, and a mutual significant association existed. These shared differential metabolites were implicated in several metabolism pathways, including choline, tryptophan, histidine, and nicotinate and nicotinamide metabolism, and among them, N1-methyl-4-pyridone-3-carboxamide, 5’-methylthioadenosine, and kynurenic acid were significantly associated with both maternal FPG and fetal growth. In conclusion, serum and AF metabolic profiles were remarkably altered in response to GDM. N1-Methyl-4-pyridone-3-carboxamide, 5’-methylthioadenosine, and kynurenic acid have the potential to be taken as biomarkers for maternal–fetal health status of GDM. The common and inter-related differential metabolites both in the serum and AF implied the feasibility of predicting fetal health outcomes via detecting the metabolites in maternal serum exposed to GDM.

The study was designed to develop and validate the nutrition literacy assessment instrument for pregnant women in China (NLAI-P). The dimension, components and questions of NLAI-P were identified via literature review and expert consultation. A panel of experts evaluated the content validity. The construct validity was evaluated by using the exploratory factor analyses (EFA) and confirmatory factor analyses (CFA). Cronbach’s α coefficient and split-half reliability were applied for examining the reliability. The NLAI-P was divided into 3 dimensions including knowledge, behavior and skill dimension. Findings showed NLAI-P possessed the satisfactory content validity (content validity index = 0.98, content validity ratio = 0.97), acceptable construct validity (χ²/df = 1.82, GFI = 0.86, AGFI = 0.84, RMSEA = 0.046) and good reliability (Cronbach’s α coefficient = 0.82). The average scores of NLAI-P were 46.59 ± 9.27. With the adjustment of confounding factors, education level presented a significantly positive correlation with NLAI-P scores. In conclusion, NLAI-P were valid and reliable to inspect NL level of pregnant women in China. Poor NL was prevalent among Chinese pregnant women. Based on the education level, taking targeted propaganda and education measures would achieve the optimal effect. NLAI-P can be applied as the tool for monitoring and assessing NL of pregnant women, and facilitate the designation of targeted interventions policies.

• 70 Human milk oligosaccharides (HMOs) were effectively identified by UPLC-QE-HF-MS. • 14 Bovine milk oligosaccharides (BMOs) were effectively identified by UPLC-QE-HF-MS. • 23 Goat milk oligosaccharides (GMOs) were effectively identified by UPLC-QE-HF-MS. • The nature and number of OS in human and animal milk were significantly different. • 14 Neutral and 3 acidic oligosaccharides (OS) were reported at first time in rat milk. • The composition and abundance of RMOs were more similar to that of HMOs.

Currently, it must be acknowledged that little is known about the quantity and make-up of oligosaccharides (OS) found in breast-fed babies’ feces as well as their metabolic fate. In the present work, UPLC-QE-HF-MS was successfully adopted to identify the profiles of human milk oligosaccharides (HMOs) in the breast milk of four mothers and fecal OS in the feces of their breast-fed infant. There were significant variations and differences in both number and composition between HMOs and fecal OS. The early-life gastrointestinal microbiota metabolism may be triggered into the advanced breakdown, synthesis, bioconversion, or redesign of HMOs. The fate of HMOs during passage through the gastrointestinal tract may be profoundly informed by the comparison of OS between breast milk and fecal OS profiles. The characterization of fecal OS could be applied as a valuable tool for monitoring the gastrointestinal fate of HMOs and reflecting infant development at different stages of lactation. Further research on the gastrointestinal bioconversion of HMOs profiles is required, including secretor type and the lactation time of milk, as well as baby feeding.