Renal fibroblast-like cells in Goodpasture syndrome rats

Background. The extent of renal fibrosis is the best predictor for function al outcomes in a variety of progressive renal diseases. Interstitial fibrob last-like cells (FbLCs) are presumably involved in the fibrotic process. Ho wever. such FbLCs have never been well characterized in the kidney. Methods. We characterized renal FbLCs in the nephritic kidney (in which the number of FbLCs and extracellular matrix accumulation were significantly i ncreased) with regards to their expression of phenotypic and functional mar kers using day 49 Goodpasture syndrome (GPS) rats. Results. Within the renal cortical interstitium. there were a number of alp ha -smooth muscle actin(+) (alpha -SMA(+)) FbLCs, negative for vimentin (VI M) and transforming growth factor-beta1, and not equipped with well-develop ed rough endoplasmic reticulum and actin-stress fibers. All of these findin gs were incompatible with the typical features of granulation tissue alpha -SMA(+) myofibroblasts. On the other hand. FbLCs negative for alpha -SMA an d VIM produced alpha1(I) procollagen in the nephritic kidney. Conclusion. A number of FbLC populations reside within the cortical interst itium of the kidney in GPS rats, each of which is likely to have developed independently in response to the local conditions of the nephritic kidney. contributing To renal fibrogenesis. Further studies are needed to clarify t he key type of FbLC that orchestrates other members to produce renal fibros is.