RESUMO
BACKGROUND/AIMS: Activation of myofibroblasts occurs during kidney injury. Genomic and proteomic studies suggest that transgelin represents a protein that may be involved in renal injury. The purpose of this study was to estimate transgelin expression in the renal tissue of patients with glomerulonephritis. METHODS: Transgelin was identified in biopsy sections of 67 patients by immunohistochemistry and immunofluorescence. Its distribution was compared to that of α-smooth muscle actin (α-SMA), a marker of myofibroblast activation in the kidney. RESULTS: Transgelin and α-SMA expression was identified within glomeruli and interstitium. In patients with IgA nephropathy and focal segmental glomerulosclerosis, glomerular expression of transgelin was higher than that of α-SMA. The extent of transgelin immunostaining was related to mesangial proliferation (p = 0.034), glomerular sclerosis (p = 0.035), interstitial fibrosis (p = 0.047) and to the clinical course (p = 0.009). Colocalization studies showed that in some areas of kidney tissue both proteins were expressed with comparable intensity, whereas in other areas expression of either transgelin or α-SMA was predominant. CONCLUSION: Strong transgelin expression was observed in renal tissue of patients with glomerulonephritis. The observed differences in the pattern of transgelin and α-SMA expression suggest that either different subpopulations of myofibroblasts exist, or that these proteins are activated at different stages of renal injury/scarring.
