Morphology of renal interstitial fibroblasts

Renal fibrogenesis is a process common to all progressive kidney diseases. The main executive cell in this process is the fibroblast, by secreting and remodelling the extracellular matrix. The number of fibroblasts is minor in a healthy kidney interstitium, but it increases during the process of fibrosis. Their morphology and immunophenotype vary due to different intrinsic and extrinsic factors which makes their identification and visualization, as well as determination of their origin, very difficult.

We performed morphological and immunohistochemical analyses on kidney biopsies with interstitial fibrosis, using the following antibodies: Vimentin, α-SMA, S100A4, Cadherin 9 and CD34. We also did light-microscopy analyses of semithin sections of tissue embedded in epoxy resin and stained with Toluidine blue.

Our observations show that different cells in the fibroblastic population show positivity for different markers, thus contributing to the theory that there are different subpopulations of fibroblasts, with different origins, that take part in renal fibrogenesis.