Matrigel plus N-Acetylcysteine deactivate human pancreatic stellate cells and interfere with matrix remodeling

Background/Aims: Tissue fibrosis is one of the characteristics of chronic pancreatitis and pancreatic adenocarcinoma. Activated pancreatic stellate cells (PSC) play a central role in this process. In the last years several factors resulting in activation of PSC have been identified, however, up to now now no efficient therapy fort he treatment of pancreatic fibrosis has been developed. Methods: Primary activated pancreatic stellate cells were isolated by the outgrowth method. The effects of cultivation on basement membrane components or N-Acetylcysteine (NAC) treatment on gene and protein expression and proliferation of primary activated human PSC and on immortalized human PSC were analyzed. Methods used included RT-PCR and real-time RT-PCR, Western Blot and WST–1 assay. Fat storing of the cells was visualized by Oil Red staining. Moreover the expression of active MMPs was analyzed using substrate gel zymography Results: Incubation of immortalized and primary human activated PSC on Matrigel plus NAC treatment resulted in a deactivated phenotype as evidenced by a decrease of αSMA, CTGF and Col I expression and by a decreased proliferation of the cells. This treatment also restored the ability of the cells to store vitamin A in cytoplasmic vesicles. Moreover this treatment markedly reduced the expression of active MMP–2 and MMP–9 in the immortalized PSC as revealed by substrate gel zymography. Conclusion: We were able to demonstrate that besides soluble factors, the matrix surrounding pancreatic stellate cells plays a pivotal role in the maintenance of the activation process of PSC. Cultivation of activated PSC on a reconstituted basement membrane plus treatment with NAC was able to deactivate the cells, additionally this treatment interferes with the degradation of the normal basal membrane, by downregulation of MMP–2 and MMP–9 expression. Thus this treatment points to the possibility of an antifibrosis therapy in chronic pancreatitis.

Keywords: activation, pancreatic stellate cells, pancreatitis