Related Experiment Video
Updated: Jan 15, 2026

In Vitro Culture of Epithelial Cells from Different Anatomical Regions of the Human Amniotic Membrane
Published on: November 28, 2019
Amniotic Fluid Extracellular Vesicle Properties Evolve With Gestational Age and Reflect Fetal Development
Ishara Atukorala1,2,3, Sally Beard4, Ching-Seng Ang5
1Department of Obstetrics, Gynaecology and Newborn Health, Melbourne Medical School The University of Melbourne Heidelberg Victoria Australia.
None:
Amniotic fluid (AF) is a valuable source of extracellular vesicles (EVs) derived from the fetoplacental unit. Preclinical and clinical studies have highlighted promising applications of AF-EVs and their role in cellular communication, yet our understanding of AF-EV physiology remains limited. This study aimed to examine the physiological importance of AF-EVs in fetal development from the second trimester to term gestation. We obtained AF samples from routine second-trimester amniocentesis and prelabour Caesarean section at term. We isolated EVs using a combination of differential centrifugation, filtration and ultracentrifugation and characterised them using nanoparticle tracking analysis, cryo-electron microscopy and Western blotting. The differential EV proteome was analysed using label-free proteomics. We assessed the second trimester and term AF-EV properties through an enrichment analysis. The EV size and protein enrichment difference revealed a gestational-age-dependent variation in the predominant EV subtype. Second-trimester-derived EVs were enriched in ectosomes, while term EVs contained a significant proportion of exosomes. We identified several morphologies of AF-EVs, including unilamellar, multilamellar, multicompartmental and granular-centred EVs, across gestational ages. Proteomics analysis of AF-EVs identified 4137 proteins with high confidence, of which 1090 exhibited significant differential enrichment between the two groups. Second-trimester-enriched AF-EV proteins represented molecule assembly processes, metabolism and organogenesis. At term, AF-EV proteins corresponded to impending newborn functions such as immunity and digestion. In conclusion, we provide compelling evidence that EV biogenesis and secretion in the fetoplacental unit undergo significant alterations across gestational ages, revealing a complex and dynamic physiology and intercellular communication that adapts to the needs of the developing fetus.
Related Concept Videos
Transcytosis of IgG
IgG molecules from a mother undergo transcytosis starting around 13 weeks of gestation. The amount of IgG transferred and entering the fetal blood circulation increases with...
Development of Blood Vessels
The initial formation of this system is facilitated by the small amount of yolk present in the ovum and yolk sac. Blood vessels originate from...
Embryonic Connective Tissues
The mesenchyme is the first connective tissue that emerges in the developing embryo. It consists of loosely arranged multipotent mesenchymal cells and reticular fibers in the extracellular matrix. This loose arrangement allows easy migration of cells, which is essential for germ layer positioning, patterning, and organ morphogenesis during embryonic development.
Cleavage and Blastulation
Fetal Circulation
Two umbilical arteries transport blood from the fetus to the placenta. At the placenta, the blood absorbs oxygen and nutrients while simultaneously eliminating waste products. This oxygen-enriched and nutrient-rich blood then returns to the fetus through one...
Membrane Fluidity

