Vascularization has been a major
challenge in the development of
a bioengineered liver. We aimed to develop a functionalized vascular
structure in bioengineered liver and to identify the biological vascularization
processes at different time points using proteomics. Decellularized
rat liver scaffolds were vascularized with human umbilical vein endothelial
cells (HUVECs) for 1, 3, 7, 14, and 21 days. HUVECs adhered to the
internal surface and formed a functional barrier structure within
7 days. Vascularized liver scaffolds with biological activity were
sustained for more than 21 days in vitro. Proteomics analysis indicated
distinct characteristics after 14 days of culture compared with other
time points. The biological processes of proteins expressed at days
1, 3, and 7 mainly involved cell adhesion, protein synthesis, and
energy metabolism; however, different biological processes associated
with muscle contraction and muscle filament sliding were identified
at days 14 and 21. Coexpressed proteins at days 14 and 21 participated
in 7 biological processes that could be classified as angiogenesis,
myogenesis, or vascular function. Furthermore, the validation of related
proteins revealed that basement membrane assembly, phenotype plasticity
of HUVECs, and the regulation of adherence junctions contribute to
the formation of a functionalized vascular structure. The biological
vascularization processes at different time points identified with
proteomics revealed development characteristics of vascular structure
in a bioengineered liver, and at least 14 days of in vitro culture
should be recommended for developing a functionalized vascular structure.
This study may help to provide a better understanding of the mechanism
of vascularization and facilitate the construction of a functional
bioengineered liver for future clinical applications.