VMP1 Expression Correlates with Acinar Cell Cytoplasmic Vacuolization in Experimental Pancreatitis

VACCARO MI; GRASSO D; SANCHEZ S; ROPOLO A; IOVANNA JL

Liverpool, UK.

Congreso; 35th European Pancreatic Club (EPC) Meeting; 2003

European Pancreatic Club

Introduction: Recently, we described the cloning of VMP1 (Vacuole Membrane Protein 1). In vitro expression of VMP1 promotes formation of cytoplasmic vacuoles followed by cell death. In order to test if VMP1 expression is related to the cytoplasmic vacuolization of the acinar cells during pancreatitis, we studied the in vivo expression of the new gene during arginine-induced pancreatitis. Methods: Male Wistar rats injected with 500 mg/100 g of L-arginine were time course sacrificed and pancreas removed. Results: Northern blot analysis showed maximal induction of VMP1 after 24 h remaining high after 48 h of treatment. Significant increase in the number of TUNEL stained cells were found at those periods. Light micrographs from thin plastic toluidine blue sections revealed numerous vacuoles in the cytoplasm of acinar cells. In situ hybridization studies showed high expression of VMP1 in acinar cells with cytoplasmic vacuolization. The percent of cells with vacuoles and the percent of cells with high VMP1 mRNA signal were determined after 24 h of pancreatitis. Correlation analysis indicated that the formation of vacuoles is significantly related (r: 0.9513) to the VMP1 expression. Conclusion: These results suggest that VMP1 expression may be involved in the cytoplasmic vacuolization of acinar cells during the early stage of acute pancreatitis.