Sergio A. Mezzano

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IgA nephropathy is the most common glomerular disease worldwide, yet there is no international consensus for its pathological or clinical classification. Here a new classification for IgA nephropathy is presented by an international consensus working group. The goal of this new system was to identify specific pathological features that more accurately(More)
Angiotensin (Ang) II mediates pathophysiologial changes in the kidney. Ang-(1-7) by interacting with the G protein-coupled receptor Mas may also have important biological activities.In this study, renal deficiency for Mas diminished renal damage in models of renal insufficiency as unilateral ureteral obstruction and ischemia/reperfusion injury while the(More)
BACKGROUND Nuclear factor-kappaB (NF-kappaB) and activated protein-1 (AP-1) are transcription factors that regulate many genes involved in the progression of renal disease. Recent data have shown that NF-kappaB is activated in tubules and glomeruli in various experimental models of renal injury. In vitro studies also suggest that proteinuria could be an(More)
Inflammatory cell infiltration plays a key role in the onset and progression of renal injury. The NF-kappaB participates in the inflammatory response, regulating many proinflammatory genes. Angiotensin II (Ang II), via AT(1) and AT(2) receptors, activates NF-kappaB. Although the contribution of Ang II to kidney damage progression is already established, the(More)
BACKGROUND Emerging evidence suggests that angiotensin II (Ang II) is not only a vasoactive peptide, but also a true cytokine that regulates cell growth, inflammation and fibrosis. Many studies have demonstrated that this peptide plays an active role in the progression of renal injury. Some of Ang II-induced effects are mediated by the production of a large(More)
BACKGROUND We report the induction of gremlin, a bone morphogenetic protein antagonist, in cultured human mesangial cells exposed to high glucose and transforming growth factor beta (TGF-beta) levels in vitro and kidneys from diabetic rats in vivo. METHODS Gremlin expression was assessed in human diabetic nephropathy by means of in situ hybridization,(More)
The renin-angiotensin system (RAS) has emerged as one of the essential links in the pathophysiology of vascular disease. Angiotensin (Ang) II, the main peptide of the RAS, was considered as a vasoactive hormone, but in the past years, this view has been modified to a growth factor that regulates cell proliferation/apoptosis and fibrosis. Recently, this view(More)
Pathological classifications in current use for the assessment of glomerular disease have been typically opinion-based and built on the expert assumptions of renal pathologists about lesions historically thought to be relevant to prognosis. Here we develop a unique approach for the pathological classification of a glomerular disease, IgA nephropathy, in(More)
BACKGROUND We have previously demonstrated the preferential secretion of streptococcal proteinase or streptococcal pyrogenic exotoxin B (SPEB) by nephritic strains of Group A streptococci isolated from the skin or throat of patients with acute poststreptococcal glomerulonephritis (APSGN). METHODS To further explore the possible role of SPEB in APSGN, we(More)