Mapping the true 3D architecture: Quantitative morphological diversity of human hepatic functional unit revealed by fluorescence micro-optical section tomography.

BACKGROUND & AIMS: Mapping true 3D architecture of liver microstructure is important for understanding the physiology and pathology of the hepatic lobule and enabling hepatic tissue 3D printing. However, the existing 3D architecture of liver microstructure coming from traditional textbooks, references and atlases may not be sufficiently accurate. Our study aims to reconstruct the true 3D architecture of human hepatic microstructure and present its true 3D morphology. METHODS: Two-dimensional (2D) successive sectional images of human liver tissue were obtained using fluorescence micro-optical section tomography, and Amira software was used to segment and 3D reconstruct the microstructures of 29 liver hepatic lobules and then calculate and statistically analyze their key morphological parameters. RESULTS: The hepatic lobules were divided into the mango (55%), date pit (24%) and gyroscope types (21%) based on their shape. The hepatic lobule was 461.70 ± 100.13 µm in diameter, the longitudinal axis 1389.66 ± 499.47 µm in length, the ratio of diameter/longitudinal axis length 0.36 ± 0.09, and the volume of the hepatic lobules (3.13 ± 2.39) × 107 μm3. Most of the sublobular veins were adjacent to the hepatic lobules (79%), but a few penetrated the hepatic lobules (21%). The central veins were divided into single-trunk (34%), double-trunk (7%), double-tributary (45%) and multitributary types (14%). The central veins did not penetrate the entire hepatic lobules, and the length ratio of the central vein to the longitudinal axis was 0.47 ± 0.16. CONCLUSIONS: This is the first study to provide comprehensive, detailed 3D reconstruction and quantitative analysis of intact human hepatic lobules and their adjacent structures, contributing to the revision of classical hepatic microanatomy and advancing hepatic tissue engineering.