Telomerized human microvasculature is functional in vivo

Area of Science:

• Regenerative Medicine
• Vascular Biology
• Biotechnology

Background:

• Human telomerase reverse transcriptase (hTERT) enhances in vitro survival of human endothelial cells (EC).
• Previous studies demonstrated the superior in vitro survival of hTERT-transduced EC.

Purpose of the Study:

• To investigate the in vivo formation and durability of microvascular structures derived from hTERT-transduced human dermal microvascular EC (HDMEC).
• To establish a xenograft model for studying human microvascular remodeling.
• To assess the functionality and integration of engineered human vasculature in a host environment.

Main Methods:

• Retroviral-mediated transduction of hTERT into HDMEC.
• Subcutaneous implantation of transduced HDMEC into severe combined immunodeficiency (SCID) mice.
• Immunohistochemical analysis using anti-human type IV collagen and enhanced green fluorescent protein (eGFP) labeling.
• Assessment of functional anastomosis using fluorescent microspheres.
• Longitudinal evaluation of vessel density and durability over six weeks.

Main Results:

• hTERT-transduced HDMEC formed stable, human-origin microvascular structures in SCID mice, confirmed by immunoreactivity and eGFP labeling.
• Functional murine-human vessel anastomoses were established, indicated by microsphere presence within engineered vessels.
• Unlike primary HDMEC, telomerized HDMEC maintained durable vessels for at least six weeks post-xenografting.
• Implantation of control cells (fibrosarcoma, kidney, fibroblasts) did not result in human vasculature.
• The system allowed for modulation of vessel density by angiogenic and angiostatic factors.

Conclusions:

• Retroviral transduction of hTERT in HDMEC generates durable human microvessels in vivo.
• This xenograft model provides a valuable platform for studying human microvascular remodeling and angiogenesis.
• The engineered vasculature demonstrates functional integration with the host circulatory system.