title: Blocking ligand occupancy of the αVβ3 integrin inhibits the development of nephropathy in diabetic pigs.
abstract: Hyperglycemia stimulates secretion of αVβ3 ligands from vascular cells, including endothelial cells, resulting in activation of the αVβ3 integrin. This study determined whether blocking ligand occupancy of αVβ3 would inhibit the development of diabetic nephropathy. Ten diabetic pigs received an F(ab)2 fragment of an antibody directed against the extracellular domain of the β3-subunit, and 10 received a control IgG F(ab)2 for 18 weeks. Nondiabetic pigs excreted 115 ± 50 μg of protein/mg creatinine compared with control F(ab)2-treated diabetic animals (218 ± 57 μg/mg), whereas diabetic animals treated with the anti-β3 F(ab)2 excreted 119 ± 55 μg/mg (P < .05). Mesangial volume/glomerular volume increased to 21 ± 2.4% in control-treated diabetic animals compared with 14 ± 2.8% (P < .01) in animals treated with active antibody. Diabetic animals treated with control F(ab)2 had significantly less glomerular podocin staining compared with nondiabetic animals, and this decrease was attenuated by treatment with anti-β3 F(ab)2. Glomerular basement membrane thickness was increased in the control, F(ab)2-treated diabetic animals (212 ± 14 nm) compared with nondiabetic animals (170 ± 8.8 nm), but it was unchanged (159.9 ± 16.4 nm) in animals receiving anti-β3 F(ab)2. Podocyte foot process width was greater in control, F(ab)2-treated, animals (502 ± 34 nm) compared with animals treated with the anti-β3 F(ab)2 (357 ± 47 nm, P < .05). Renal β3 tyrosine phosphorylation decreased from 13 934 ± 6437 to 6730 ± 1524 (P < .01) scanning units in the anti-β3-treated group. We conclude that administration of an antibody that inhibits activation of the β3-subunit of αVβ3 that is induced by hyperglycemia attenuates proteinuria and early histologic changes of diabetic nephropathy, suggesting that it may have utility in preventing the progression of this disease complication.
authors.affiliation: Department of Medicine (L.A.M., W.H.B., K.A.G., T.N., D.B., A.P., P.D., M.M., D.C.), University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599; and Department of Animal Science (W.F., N.G., S.G., K.S.), North Carolina State University, Raleigh, North Carolina 27695.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Maile
authors.forename: Walker H
authors.initials: WH
authors.lastname: Busby
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Gollahon
authors.forename: William
authors.initials: W
authors.lastname: Flowers
authors.forename: Nikol
authors.initials: N
authors.lastname: Garbacik
authors.forename: Stefani
authors.initials: S
authors.lastname: Garbacik
authors.forename: Kara
authors.initials: K
authors.lastname: Stewart
authors.forename: Timothy
authors.initials: T
authors.lastname: Nichols
authors.forename: Dwight
authors.initials: D
authors.lastname: Bellinger
authors.forename: Amit
authors.initials: A
authors.lastname: Patel
authors.forename: Paul
authors.initials: P
authors.lastname: Dunbar
authors.forename: Matt
authors.initials: M
authors.lastname: Medlin
authors.forename: David
authors.initials: D
authors.lastname: Clemmons
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D003928:Diabetic Nephropathies / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D050533:Glomerular Basement Membrane / Q000473:pathology; D039302:Integrin alphaVbeta3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008297:Male; D008807:Mice, Inbred BALB C; D050199:Podocytes / Q000473:pathology; D011507:Proteinuria / Q000209:etiology; D013552:Swine
chemical_list: D000911:Antibodies, Monoclonal; D039302:Integrin alphaVbeta3