Expression of Glomerular-Smooth Muscle Actin and Vimentin in Idiopathic Membranous Nephropathy as Prognostic Indicators

Lee, Min Jin; Kim, Ok Kyung

Abstract

BACKGROUND: The natural history of idiopathic membranous nephropathy (IMN) is heterogeneous with some patients showing spontaneous remission while others show a progressive course leading to end-stage renal failure. We tried to assess quantitatively alpha-smooth muscle actin (alpha-SMA) and vimentin expression as markers to predict the outcome of membranous nephropathy.
METHODS
This study included 24 patients with biopsy proven IMN. We measured the volume of the positive area for alpha-SMA and vimentin within the glomeruli and compared the results with 5 patients in the normal control group. We evaluated glomerular alpha-SMA and vimentin expression in correlation with BUN and serum creatinine level at the time of diagnosis and after treatment.
RESULTS
Glomerular alpha-SMA and vimentin in IMN were higher than in the control group. Glomerular alpha-SMA was significantly higher in progressive IMN than in non-progressive IMN. The glomerular alpha-SMA was sifnificantly correlated with BUN and serum creatinine at last follow-up (p<0.05), but there was no statistically significant correlation at diagnosis. The glomerular vimentin was not different between progressive and non-progressive groups.
CONCLUSION
These data suggest that the expression of glomerular alpha-SMA may be a useful prognostic indicator and may be able to differentiate between patients with membranous nephropathy who respond well to treatment and those who continue to progress.