Telomerized human microvasculature is functional in vivo
Jiwei Yang1, Usha Nagavarapu1, Kenneth Relloma1, Michael D. Sjaastad2, William C. Moss3, Antonino Passaniti4
& G. Scott Herron1
1
Department of Dermatology, Stanford University School of Medicine, Stanford, CA 94305, and The Molecular Medicine Research Institute, Mountain View, CA 94043.
2
Universal Imaging Corporation, West Chester, PA 19380.
3
Lawrence Livermore National Laboratory, Livermore, CA 94550.
4
Department of Pathology, Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201.
Correspondence should be addressed to G. Scott Herron gsherron@mmrx.org
Previously we showed the superior in vitro survival of human telomerase reverse transcriptase (hTERT)-transduced human endothelial cells (EC). Here we show that retroviral-mediated transduction of hTERT in human dermal microvascular EC (HDMEC) results in cell lines that form microvascular structures when subcutaneously implanted in severe combined immunodeficiency (SCID) mice. Anti-human type IV collagen basement membrane immunoreactivity and visualization of enhanced green fluorescent protein (eGFP)-labeled microvessels confirmed the human origin of these capillaries. No human vasculature was observed after implantation of HT1080 fibrosarcoma cells, 293 human embryonic kidney cells, or human skin fibroblasts. Intravascular red fluorescent microspheres injected into host circulation were found within green "telomerized" microvessels, indicating functional murine−human vessel anastamoses. Whereas primary HDMEC-derived vessel density decreased with time, telomerized HDMEC maintained durable vessels six weeks after xenografting. Modulation of implant vessel density by exposure to different angiogenic and angiostatic factors demonstrated the utility of this system for the study of human microvascular remodeling in vivo.
