High resolution, serial imaging of early mouse and human liver bud morphogenesis in three dimensions

Abstract

Liver organogenesis has thus far served as a paradigm for solid organ formation, and has recently attracted interest due to challenges faced in liver regenerative medicine. Murine genetic studies indicate that early steps in morphogenesis are required, suggesting that three-dimensional imaging of early liver morphogenesis at high resolution can improve our understanding. Unfortunately, existing approaches to image early liver morphogenesis have been unable to achieve high spatial resolution (1-5 um) required. In this study, we focused on imaging, visualization, and analysis of early liver development. We utilized available online databases for both mouse (EMAP) and human (3D Atlas of Human Embryology) liver development. To visualize liver bud morphogenesis at high spatial resolution, we performed 3D reconstructions of stacked, digital tissue sections. We show dynamic 3D hepatic cord formation in the mouse in humans. Interestingly, when we quantified fetal liver growth, we showed that 3D fetal liver growth appears to occur in spurts rather continuously, and 3D images suggest that there could be considerable remodeling during these stages. Further, our analysis of the STM, in both mouse and humans, demonstrates that it increases in size during early fetal liver growth, that is highly interconnecting with liver epithelium, and that it can have strong local effects on growth. Finally, we identify and visualize and identify human hepatic cord formation followed by rapid sheet-like growth, which we propose could be an under-appreciated morphological feature that enables rapid growth of early human fetal liver. These studies will motivate future approaches to employ in vitro culture and organoid technology to improve human PSC differentiation, and improve disease modeling, and therapeutic opportunities for liver diseases. In conclusion, compared to 2D sectioning, high spatial resolution imaging of the mouse and human 3D liver bud morphogenesis enables greatly improved visualization of the hepatic cords, 3D sheet-like liver cell growth, STM-epithelial cell interactions, and quantitative comparisons between mouse and human liver bud morphogenesis.

Peculiarities of the Identification of Different Types of Tissues During 3d-Reconstruction of Human Microscopic Structures

“…The research was conducted on 6 series of consecutive histological sections of human embryos aged 4 to 6 weeks of IUD, 15 samples of organ complexes of the head, limbs and trunk of human prefetuses aged 7 to 12 weeks of IUD, human fetuses aged 4 to 9 months of IUD by the method of making histological (5), as well as histotopographic sections (10) directly from the paraffi n block and their digitization, and 14 CT of human fetuses aged 4 to 9 months of IUD.…”

“…It is known that the fi rst 3D computer reconstruction was performed in 1984 due to the development of computer technologies [8,9]. Since then, anatomists, histologists, topographical anatomists, embryologists have included it in the complex of morphological research methods as a rather informative and objective method [10,11]. In addition, this technology corresponds to the main principles of modern diagnostic medical imaging, therefore it contributes to the improvement of interpretation of non-invasive diagnostic methods [12].…”

“…, а також гістотопографічних зрізів (10) безпосередньо з парафінового блоку та їх оцифровки, та 14 КТ плодів людини віком від 4 до 9 місяців ВУР.…”

Liver organoids: From fabrication to application in liver diseases

“…After the liver organoid is generated, its performance can usually be assessed in vitro by morphological tests (Broutier et al, 2016;Aloia et al, 2019;Ogoke et al, 2022), functional tests (Akbari et al, 2019), such as P450 activity assays, and single-cell sequencing (Elbadawy et al, 2020). Compared to morphological and functional tests, single-cell sequencing is more reflective of the similarity between the organoid and the primary liver.…”