Renal expression of alpha-smooth muscle actin and c-Met in children with Henoch–Schönlein purpura nephritis

Abstract

Alpha-smooth muscle actin (alpha-SMA) is the actin isoform that predominates within vascular smooth-muscle cells and plays an important role in fibrogenesis. On the other hand, c-Met is the receptor for hepatocyte growth factor (HGF), which plays a role in protection from injury and has anti-fibrogenetic effects. To clarify whether alpha-SMA and HGF are associated with the progression of renal injury in Henoch-Schönlein purpura nephritis (HSPN), we evaluated the renal expression of alpha-SMA and c-Met in HSPN patients. Patients were divided into three groups. Group 1 consisted of eight patients (male:female 4:4) with stage II or less in the classification of the International Study of Kidney Disease in Children (ISKDC), Group 2 consisted of 20 patients (male:female 11:9) with ISKDC stage III or greater and a good prognosis, and group 3 consisted of seven patients (male:female 3:4) with ISKDC stage III or greater and poor prognosis. Renal biopsy findings, including c-Met and alpha-SMA staining, were investigated for each group. At first biopsy, the mean scores for renal alpha-SMA and glomerular c-Met in groups 2 and 3 were higher than those in group 1, while mean scores for neither renal alpha-SMA nor glomerular c-Met differed between groups 2 and 3. At second biopsy, the mean scores for renal alpha-SMA staining in group 3 were higher than those in group 2, and mean score for glomerular c-Met staining in group 3 was lower than that in group 2. In groups 2 and 3, the mean scores for glomerular and interstitial alpha-SMA staining at first biopsy were correlated with the chronicity index (CI) at second biopsy, but the mean score for glomerular c-Met staining at first biopsy correlated with neither the activity index (AI) nor CI in the first or second biopsies in all groups. Our findings suggest that the expression of renal alpha-SMA may be associated with progression of renal injury in HSPN.

HENOCH-SCH^|^Ouml;NLEIN PURPURA NEPHRITIS IN CHILDHOOD: PATHOGENESIS, PROGNOSTIC FACTORS AND TREATMENT

“…As to the other prognostic factors, Kawasaki et al reported that the expression of renal alpha -SMA was a predictor of poor prognosis in HSPN patients 34) . Alpha -smooth muscle actin (alpha -SMA) is the predominant actin isoform within vascular smoothmuscle cells and plays an important role in fibrogenesis.…”

Changes in keratins and alpha-smooth muscle actin during three-dimensional reconstitution of eccrine sweat glands

“…Alpha-SMA is an actin isoform and is commonly used as a marker for myoepithelial cells (Schon et al 1999;Nagamoto et al 2000;Kawasaki et al 2008). Diverse keratins and alpha-SMA have been established as markers of differentiation, and their expression pattern varies with the type of epithelium, stage of development, and degree of differentiation (Moll et al 1982b(Moll et al , 2008Moll and Moll 1992;Schon et al 1999;Saga 2002;Lu et al 2012;Lu and Fuchs 2014;Li et al 2015b).…”

The pathogenesis and treatment of pediatric Henoch–Schönlein purpura nephritis

“…Recently, the renal expression of alpha-smooth muscle actin (a-SMA) and c-Met, which is the receptor for hepatocyte growth factor, has also been associated with the progression of renal injury in patients with HSPN [34]. Kawasaki et al studied 35 patients in Japan with biopsyproven HSPN who were categorized into three groups: (1) nephritis with an ISKDC histological grade (the classification system used by the International Study of Kidney Disease in Children) of II or less, (2) those with ISKDC grade III or greater and a good prognosis, and (3) those with ISKDC grade III or greater and a poor prognosis.…”