title: Lymphatic microvessels in the rat remnant kidney model of renal fibrosis: aminopeptidase p and podoplanin are discriminatory markers for endothelial cells of blood and lymphatic vessels.
abstract: ABSTRACT. Rat remnant kidney is an established model of renal tubulointerstitial fibrosis and progression to end-stage renal failure. The morphologic lesions comprise nephron loss and regeneratory tubular hypertrophy, interstitial infiltration, predominately by macrophages, and progressive fibrosis. A critical role in this complex pathology was assigned to tubulointerstitial blood microvessels that regulate the supply of oxygen and nutrients of tubuli. Whereas some investigations reported a rarefaction of the vascular network in association with the degenerative cortical changes, others observed an increase in vascularization. Here these discrepant findings are addressed by reinvestigation of the vascularization of rat remnant kidneys by the use of two novel endothelial lineage specific, discriminatory markers, i.e., the membrane mucoprotein podoplanin with specificity for lymphatic endothelia, and the glycosyl-phosphatidylinositol (GPI)-anchored membrane enzyme aminopeptidase P that is recognized by a monoclonal antibody designated JG12 and that is specifically expressed by endothelial cells of blood vessels only. The results obtained confirm a regional rarefaction of aminopeptidase P-positive blood microvessels; they also establish major changes in the renal lymphatic vasculature. Massive proliferation of lymphatic vessels was observed in fibrotic tubulointerstitial regions, whereas in kidneys of sham-operated rats, only a few lymphatic vessels were found adjoined with arteries. The lymphatic vessels frequently contained mononuclear cells that were also encountered in the interstitial spaces and expressed relative large amounts of vascular endothelial growth factor-C mRNA by in situ hybridization. Collectively, these results indicate that a large proportion of the microvessels encountered in the cortex of remnant kidneys are of lymphatic origin and cannot be discriminated by common endothelial markers, such as CD34, that are expressed by both lymphatic and blood endothelia cells. As lymphatic endothelial cells secrete chemokines that attract dendritic cells, it is possible that the increase in lymphatic vascularization could enhance the immunologic surveillance of remnant kidneys.
authors.affiliation: Institute of Clinical Pathology, University of Vienna, Allgemeines Krankenhaus, Vienna, Austria.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Matsui
authors.forename: Katalyn
authors.initials: K
authors.lastname: Nagy-Bojarsky
authors.forename: Pirjo
authors.initials: P
authors.lastname: Laakkonen
authors.forename: Sigurd
authors.initials: S
authors.lastname: Krieger
authors.forename: Karl
authors.initials: K
authors.lastname: Mechtler
authors.forename: Shunya
authors.initials: S
authors.lastname: Uchida
authors.forename: Silvana
authors.initials: S
authors.lastname: Geleff
authors.forename: Duk-Hee
authors.initials: DH
authors.lastname: Kang
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Johnson
authors.forename: Dontscho
authors.initials: D
authors.lastname: Kerjaschki
authors.forename: Due-Hee
authors.initials: DH
authors.lastname: Kang
mesh_terms: D000626:Aminopeptidases / Q000737:chemistry*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D018952:Antigens, CD34 / Q000096:biosynthesis; D001483:Base Sequence; D002455:Cell Division; D019070:Cell Lineage; D018925:Chemokines / Q000378:metabolism; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000378:metabolism*; D005355:Fibrosis / Q000473:pathology*; D017261:Glycosylphosphatidylinositols / Q000378:metabolism; D006801:Humans; D017403:In Situ Hybridization; D007249:Inflammation; D007668:Kidney / Q000378:metabolism / Q000473:pathology*; D007672:Kidney Cortex / Q000378:metabolism; D007678:Kidney Glomerulus / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000737:chemistry*; D008833:Microcirculation; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012689:Sequence Homology, Nucleic Acid; D013997:Time Factors; D042582:Vascular Endothelial Growth Factor C / Q000378:metabolism; D000098853:Podoplanin
chemical_list: D000626:Aminopeptidases; D000911:Antibodies, Monoclonal; D018952:Antigens, CD34; D018925:Chemokines; D017261:Glycosylphosphatidylinositols; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D042582:Vascular Endothelial Growth Factor C; C117468:PDPN protein, human; D000098853:Podoplanin; C092025:Pdpn protein, rat; C022750:X-Pro aminopeptidase