2004 Volume 16 Issue 4 Pages 301-309
Myofibroblasts expressing α -smooth muscle actin (SMA) have been implicated in the pathogenesis of tubulointerstitial fibrosis. However, the relationships between myofibroblasts, CD44 and hyaluronic acid (HA) are poorly understood. This study aimed to examine the tubulointerstitial expressions of α -SMA, CD44 and HA and to determine whether these expressions correlate with tubulointerstitial fibrosis in IgA nephropathy ( IgAN) . Renal biopsy specimens from 31 patients with IgAN were examined by immunohistochemistry to analyze the protein expressions of α -SMA, CD44, HA, CD68, collagen type (Col) I, Col III, and Col IV. Stained biopsy sections were scored semiquantitatively. The tubulointerstitial fibrosis was also evaluated quantitatively using an image analyzer. The relationship between the pathological and clinical data was also studied. The extent of tubulointerstitial fibrosis is associated with a reduction in renal function. The expression of α -SMA in the tubulointerstitium correlated with the expression of CD44 and the interstitial deposition of HA. Double-staining immunohisto-chemistry revealed CD44-positive myofibroblasts in interstitial lesions. Moreover, CD44-positive cells were localized in the areas of HA deposition. These results suggest that CD44-positive myofibroblasts play an important role in the pathogenesis of tubulointerstitial fibrosis in IgAN, through several mechanisms including a CD44-HA interaction.
