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Significance of mesangial expression of α-smooth muscle actin in the progression of IgA nephropathy

1999; Elsevier BV; Volume: 34; Issue: 5 Linguagem: Inglês

10.1016/s0272-6386(99)70049-1

1523-6838

Yasunori Utsunomiya, Tetsuya Kawamura, Aya Abe, Hiroko Imai, Keita Hirano, Naoki Maruyama, Tatsuo Hosoya, Osamu Sakai,

Platelet Disorders and Treatments

To determine whether phenotypic modulation of mesangial and interstitial cells correlated with the long-term prognosis of IgA nephropathy (IgAN), we analyzed retrospectively 27 patients with IgAN whose creatinine clearance at the time of renal biopsy was normal. The patients were subdivided into two groups according to the course of renal function during follow-up. Thirteen patients maintained normal renal function for more than 15 years (stable group), and 14 progressed to end-stage renal disease (ESRD group). The score of mesangial cell cellularity in the ESRD group was significantly higher than in the stable group. Immunohistochemistry localized α-smooth muscle actin (α-SMA) in renal mesangial cells of approximately half these patients. Macrophages localized predominantly in the mesangial area in patients with mesangial expression of α-SMA, which was associated with the expression of macrophage–colony-stimulating factor. Noteworthily, the score of mesangial α-SMA expression and the incidence of patients with mesangial expression of α-SMA at the time of renal biopsy were markedly higher in the ESRD group than in the stable group. However, there was no significant difference in both the score of interstitial α-SMA expression and the incidence of patients with interstitial expression of α-SMA between these two groups. These results suggest that macrophages recruited into the mesangium may induce phenotypic modulation of mesangial cells and that mesangial α-SMA expression predicts a progressive decline in renal function in patients with IgAN.