ABSTRACT
BACKGROUND: Hyperfiltration in the glomeruli have been considered to be an important cause of glomerular injury; however, the role of intercellular adhesion molecule (ICAM)-1 in the pathogenesis of glomerulosclerosis is not known. METHODS: To elucidate the effects of ICAM-1 depletion on hyperfiltration-induced glomerular disorder, we used subtotally nephrectomized ICAM-1(+/+) and ICAM-1(-/-) mice. We evaluated macrophage infiltration, mesangial matrix expansion, transforming growth factor (TGF)-ß and type IV collagen accumulation in glomeruli. RESULTS: Macrophage infiltration into the glomeruli and mesangial matrix expansion coincident with increased expression of both ICAM-1 and TGF-ß, and accumulation of type IV collagen were ameliorated in subtotally nephrectomized ICAM-1(-/-) mice compared to ICAM-1(+/+) mice. ICAM-1 depletion significantly reduced hyperfiltration-induced glomerular injury after renal ablation. CONCLUSIONS: Our present findings suggest that glomerular hyperfiltration is the leading cause of glomerulosclerosis, and it is mediated, at least in part, by ICAM-1 expression and macrophage infiltration.
Subject(s)
Intercellular Adhesion Molecule-1/physiology , Kidney Diseases/physiopathology , Kidney Glomerulus/metabolism , Animals , Collagen Type IV/biosynthesis , Kidney Diseases/pathology , Kidney Glomerulus/pathology , Macrophages/physiology , Male , Mice , Mice, Inbred C57BL , Nephrectomy , Transforming Growth Factor beta/biosynthesisABSTRACT
C-reactive protein (CRP) is one of the strongest independent predictors of cardiovascular disease. We have previously reported that oxidized LDL (oxLDL) interacts with beta2-glycoprotein I (beta2GPI), implicating oxLDL/beta2GPI complexes as putative autoantigens in autoimmune-mediated atherosclerotic vascular disease. In this study, we investigated the interaction of CRP with oxLDL/beta2GPI complexes and its association with atherosclerosis in patients with diabetes mellitus (DM). CRP/oxLDL/beta2GPI complexes were predominantly found in sera of DM patients with atherosclerosis. In contrast, noncomplexed CRP isoforms were present in sera of patients with acute/chronic inflammation, i.e., various pyrogenic diseases, rheumatoid arthritis (RA), and DM. Immunohistochemistry staining colocalized CRP and beta2GPI together with oxLDL in carotid artery plaques but not in synovial tissue from RA patients, strongly suggesting that complex formation occurs during the development of atherosclerosis. Serum levels of CRP correlated with soluble forms of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1, and oxLDL/beta2GPI complexes correlated with total cholesterol and hemoglobin A1c. Thus, the generation of CRP/oxLDL/beta2GPI complexes seems to be associated with arterial inflammation, hyperglycemia, and hypercholesterolemia. CRP/oxLDL/beta2GPI complexes can be distinguished from pyrogenic noncomplexed CRP isoforms and may represent a more specific and predictive marker for atherosclerosis.
