Placental Element Content Assessed via Synchrotron-Based X-ray Fluorescence Microscopy Identifies Low Molybdenum Concentrations in Foetal Growth Restriction, Postdate Delivery and Stillbirth.

Placental health and foetal development are dependent upon element homeostasis. Analytical techniques such as mass spectroscopy can provide quantitative data on element concentrations in placental tissue but do not show spatial distribution or co-localisation of elements that may affect placental function. The present study used synchrotron-based X-ray fluorescence microscopy to elucidate element content and distribution in healthy and pathological placental tissue. The X-ray fluorescence microscopy (XFM) beamline at the Australian Synchrotron was used to image trace metal content of 19 placental sections from healthy term (n = 5, 37-39 weeks), foetal growth-restricted (n = 3, <32 weeks, birth weight <3rd centile), postdate (n = 7, >41 completed weeks), and stillbirth-complicated pregnancies (n = 4, 37-40 weeks). Samples were cryo-sectioned and freeze-dried. The concentration and distribution of fourteen elements were detected in all samples: arsenic, bromine, calcium, chlorine, copper, iron, molybdenum, phosphorous, potassium, rubidium, selenium, strontium, sulphur, and zinc. The elements zinc, calcium, phosphorous, and strontium were significantly increased in stillbirth placental tissue in comparison to healthy-term controls. Strontium, zinc, and calcium were found to co-localise in stillbirth tissue samples, and calcium and strontium concentrations were correlated in all placental groups. Molybdenum was significantly decreased in stillbirth, foetal growth-restricted, and postdate placental tissue in comparison to healthy-term samples (p < 0.0001). Synchrotron-based XFM reveals elemental distribution within biological samples such as the placenta, allowing for the co-localisation of metal deposits that may have a pathological role. Our pilot study further indicates low concentrations of placental molybdenum in pregnancies complicated by foetal growth restriction, postdate delivery, and stillbirth.

Does the Micronutrient Molybdenum Have a Role in Gestational Complications and Placental Health?

Molybdenum is an essential trace element for human health and survival, with molybdenum-containing enzymes catalysing multiple reactions in the metabolism of purines, aldehydes, and sulfur-containing amino acids. Recommended daily intakes vary globally, with molybdenum primarily sourced through the diet, and supplementation is not common. Although the benefits of molybdenum as an anti-diabetic and antioxidant inducer have been reported in the literature, there are conflicting data on the benefits of molybdenum for chronic diseases. Overexposure and deficiency can result in adverse health outcomes and mortality, although physiological doses remain largely unexplored in relation to human health. The lack of knowledge surrounding molybdenum intake and the role it plays in physiology is compounded during pregnancy. As pregnancy progresses, micronutrient demand increases, and diet is an established factor in programming gestational outcomes and maternal health. This review summarises the current literature concerning varied recommendations on molybdenum intake, the role of molybdenum and molybdoenzymes in physiology, and the contribution these play in gestational outcomes.

"Well, what can I do?": An examination of the role supervisors, peers and scientific societies can play in the multicultural student experience.

International graduate students are a multi-cultural and diverse demographic of researchers that are integral to higher education globally. Although their contributions to research and innovation are acknowledged, the experiences of international students overseas are influenced by structural inequalities and challenges, some similar, and some unique to their domestic colleagues, that are often compounded by a "deficit narrative". This paper was defined by the inaugural 'Pressure Cooker' workshop held at the Australian and New Zealand Placental Association (ANZPRA) conference in 2022, and discusses some of the major institutional and social structures that can define an international student's graduate degree trajectory. Further, we provide examples of collaborative programs and methods for academics, scientific societies and domestic graduate peer groups to promote an equitable and accessible environment for all researchers.

Antenatal Fetal Size and Obesity in Five-Year-Old Children in a Large Cohort Created by Data Linkage.

Background: What is not well understood is the gestational age at which the fetal size deviates from normal for children who develop obesity. Here we test the hypothesis that large-for-gestational age before birth is associated with increased risk for obesity in early childhood. Methods: In this retrospective study, routinely acquired antenatal ultrasound assessments in the first, second, and third trimester were linked to anthropometric measurements at 5.5 years. Results: There were 15,760 individuals, including 678 with obesity, 1955 overweight, and 1254 thin. Compared with children of healthy weight, children who had obesity were shorter in the first trimester [mean difference 0.19 z scores (0.10, 0.28)] and heavier in the second [mean difference z scores 0.15 (0.03, 0.27)] and third trimester [mean difference z scores 0.18 (0.05, 0.32)]. Children in the thin category were lighter compared with children of healthy weight in the third trimester and those in the overweight category were heavier compared with children of healthy weight in the third trimester. All associations were independent of birth weight. Conclusions: The difference in growth trajectories between children who have obesity compared with overweight or thin suggests different underlying mechanisms.

Single-cell transcriptomics identifies CD44 as a marker and regulator of endothelial to haematopoietic transition.

The endothelial to haematopoietic transition (EHT) is the process whereby haemogenic endothelium differentiates into haematopoietic stem and progenitor cells (HSPCs). The intermediary steps of this process are unclear, in particular the identity of endothelial cells that give rise to HSPCs is unknown. Using single-cell transcriptome analysis and antibody screening, we identify CD44 as a marker of EHT enabling us to isolate robustly the different stages of EHT in the aorta-gonad-mesonephros (AGM) region. This allows us to provide a detailed phenotypical and transcriptional profile of CD44-positive arterial endothelial cells from which HSPCs emerge. They are characterized with high expression of genes related to Notch signalling, TGFbeta/BMP antagonists, a downregulation of genes related to glycolysis and the TCA cycle, and a lower rate of cell cycle. Moreover, we demonstrate that by inhibiting the interaction between CD44 and its ligand hyaluronan, we can block EHT, identifying an additional regulator of HSPC development.