In vivo formation of complex microvessels lined by human endothelial cells in an immunodeficient mouse.
We have identified conditions for forming cultured human umbilical vein endothelial cells (HUVEC) into tubes within a three-dimensional gel that on implantation into immunoincompetent mice undergo remodeling into complex microvessels lined by human endothelium. HUVEC suspended in mixed collagen/fibronectin gels organize into cords with early lumena by 24 h and then apoptose. Twenty-hour constructs, s.c. implanted in immunodeficient mice, display HUVEC-lined thin-walled microvessels within the gel 31 days after implantation. Retroviral-mediated overexpression of a caspase-resistant Bcl-2 protein delays HUVEC apoptosis in vitro for over 7 days. Bcl-2-transduced HUVEC produce an increased density of HUVEC-lined perfused microvessels in vivo compared with untransduced or control-transduced HUVEC. Remarkably, Bcl-2- but not control-transduced HUVEC recruit an ingrowth of perivascular smooth-muscle alpha-actin-expressing mouse cells at 31 days, which organize by 60 days into HUVEC-lined multilayered structures resembling true microvessels. This system provides an in vivo model for dissecting mechanisms of microvascular remodeling by using genetically modified endothelium. Incorporation of such human endothelial-lined microvessels into engineered synthetic skin may improve graft viability, especially in recipients with impaired angiogenesis.
Schechner
J S
JS
Interdepartmental Program in Vascular Biology and Transplantation, Department of Dermatology, Section of Immunobiology, Yale University School of Medicine, New Haven, CT 06536, USA. Jeffrey.Schechner@yale.edu
Nath
A K
AK
Zheng
L
L
Kluger
M S
MS
Hughes
C C
CC
Sierra-Honigmann
M R
MR
Lorber
M I
MI
Tellides
G
G
Kashgarian
M
M
Bothwell
A L
AL
Pober
J S
JS
D000818:Animals; D002196:Capillaries / Q000166:cytology* / Q000648:ultrastructure; D002478:Cells, Cultured; D018920:Coculture Techniques; D004730:Endothelium, Vascular / Q000166:cytology* / Q000648:ultrastructure; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D008854:Microscopy, Electron