Endogenous origin of glomerular endothelial and mesangial cells in grafts of embryonic kidneys. Hyink, Deborah Pinson, Diane C. Tucker, Patricia L. St. John, Vijittra Leardkamolkarn, Mary Ann Accavitti, Christine K. Abrass, and Dale R. Abrahamson. Departments of Cell Biology, Psychology, and Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, and the Department of Medicine, University of Washington, Seattle, WA
APStracts 3:0019F, 1996.
To address origins of glomerular endothelial and mesangial cells in embryonic mammalian kidneys, we established interspecies grafts between rats and mice in which fetal kidneys were implanted into the anterior eye chamber of adult hosts. After 5-7 d, hosts bearing grafts received intravenous injections with species-specific mAbs to matrix components. In all cases, glomerular basement membranes and mesangial matrices labeled solely for donor-derived matrix. Additionally, microvessel extracellular matrices within grafts were usually of donor origin. To examine directly the origin of glomerular endothelial and mesangial cells, we grafted E11 -12 kidneys from normal mice into anterior eye chambers of host ROSA26 mice, which are transgenic animals that express [beta]-galactosidase in every cell. When grafts were developed for [beta]-galactosidase activity, host cells were seen in peripheral vessels but the majority of glomerular endothelial cells were of donor, not host, origin. Where host-derived endothelial cells were found in glomeruli, donor endothelial cells were present as well. Mesangial cells were always of donor origin. When E11 mouse kidneys were labeled with the endothelial cell -specific Bandeiraea simplicifolia isolectin B4, we determined that endothelial cells are present from the inception of metanephrogenesis. Together, the evidence shows that cells of endogenous, kidney origin were almost entirely responsible for development of the glomerular microvasculature in oculo. External vessels from the host, though important for graft maintenance, were not major contributors to the glomerulus.

Received 16 October 1995; accepted in final form 14 December
1995.
APS Manuscript Number F349-5.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 29 January 96