A research team led by Prof. WU Linping from the Guangzhou Institutes of Biomedicine and Health of the Chinese Academy of Sciences, in collaboration with partners, has developed functional engineered vasculatures using a one-step bioprinting strategy. Their findings were recently published in the journal Advanced Healthcare Materials.

The global surge in aging populations has intensified the demand for treatments to replace damaged or failing organs. Tissue engineering, which focuses on creating functional tissues or cellular products, has emerged as a new solution to address the shortage of organ substitutes. However, a major bottleneck in scaling up tissue engineering technologies lies in prevascularization.

To tackle this challenge, the team developed engineered functional vasculatures and vascularized skin constructs by compartmentalizing cells within an extracellular matrix (ECM)-mimicking bioink. The bioink is designed with interpenetrated orthogonal dynamic-covalent crosslinking. This dynamic crosslinking network creates an adaptable microenvironment, which facilitates the functional compartmentalization of endothelial cells and smooth muscle cells into histological vasculature configurations.

Experimental tests validated the functionality of the engineered vasculatures. In vitro, the vasculatures exhibited contraction in response to angiotensin II, mimicking the behavior of natural blood vessels. In a mouse hind limb ischemia model, the implanted vasculatures significantly improved blood perfusion, demonstrating their ability to restore blood flow in vivo.

Additionally, the vascular network prolonged the survival and maintained the function of surrounding human dermal fibroblasts (HDFs) after implantation, thereby enhancing the healing of large full-thickness skin wounds.

To uncover the underlying mechanisms, the team conducted proteomic analysis. The results showed a significant enrichment of two key pathways in the engineered vasculatures: the hypoxia-inducible factor-1 (HIF-1) signaling pathway and the glycolysis/gluconeogenesis pathway. This suggests that the three-dimensional interaction between human umbilical vein endothelial cells (HUVECs) and vascular smooth muscle cells (VSMCs) boosts glycolysis and increases cellular ATP levels. These changes, the researchers noted, play a crucial role in forming vasculature-like structures by regulating cytoskeleton remodeling and cell migration.

Further Gene Ontology (GO) enrichment analysis revealed an upregulation of proteins associated with three key biological processes: positive regulation of integrin-mediated cell adhesion, myosin II filament assembly, and actomyosin structure organization. This indicates that the focal adhesion kinase (FAK) pathway is involved in the vasculature morphogenesis process. Specifically, the pathway couples the microscopically adaptable environment (from the bioink) to vascular organization by enhancing integrin-mediated cell adhesion and glycolysis.

This study introduces a one-step bioprinting strategy for achieving prevascularization in pre-designed architectures—a breakthrough that could advance the development of vascular tissue engineering and accelerate the translation of engineered tissues into clinical applications, the researchers noted.

This work was supported by funding from the National Key R&D Program of China and the National Natural Science Foundation of China, among other sources.