Guided vascularization in the rat heart leads to transient vessel patterning

Area of Science:

• Regenerative Medicine
• Biomaterials Science
• Cardiovascular Research

Background:

• Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) advance bioartificial heart tissue development.
• Vascularizing these engineered tissues remains a significant clinical challenge.

Purpose of the Study:

• To evaluate the efficacy of patterned endothelial cell cords in guiding vascularization of bioartificial heart tissue implanted on a rat heart.
• To assess the integration and persistence of graft-derived vasculature and cardiomyocytes.

Main Methods:

• Implantation of bioartificial tissue grafts with patterned human endothelial cell cords onto rat hearts.
• Analysis of vascularization and tissue integration using immunohistochemistry at 3 and 7 days post-implantation.
• Co-implantation of grafts with human cardiomyocytes to assess cell survival and vascular integration.

Main Results:

• Patterned endothelial cords successfully guided anastomosis and perfusion of graft microvessels with host blood within 3 days.
• Graft-derived microvessels persisted for 7 days, initially showing patterned clustering that shifted to a diffuse distribution.
• Loss of patterning correlated with CD68+ immune cell infiltration and increased collagen deposition.
• Human cardiomyocytes and graft vasculature were identified in explanted tissues.

Conclusions:

• Patterned endothelial cords provide transient guidance for vascular patterning in cardiac tissue grafts.
• The host immune response influences vessel distribution and tissue remodeling.
• Further adaptation of vascularization strategies for the epicardial environment and host response characterization are crucial for cardiac cell therapy.