Localization of transforming growth factor beta 1 and its latent binding protein in human chronic pancreatitis

Transforming growth factor beta 1 (TGF-beta 1) is thought to be the mediator of fibrosis in liver, glomerular, and pulmonary fibrosis. This study investigated the expression of TGF-beta 1 precursor (beta 1 latency-associated peptide), latent TGF-beta 1-binding protein (LTBP), and TGF-beta 1 messenger RNA (mRNA) in chronic pancreatitis. Beta 1 latency-associated peptide and LTBP expression were studied by immunohistochemistry, and TGF-beta 1 mRNA expression was studied by reverse-transcription polymerase chain reaction analysis in normal pancreatic parenchyma and in tissues from patients with chronic pancreatitis of different etiologies. In normal specimens, TGF-beta 1 precursor was present in islet cells and in a few ductal and acinar cells but not in periductal connective tissue. No immunoreactivity for LTBP was detected. In chronic pancreatitis, TGF-beta 1 precursor was detected mainly in mononuclear cells located in the fibrotic areas and also in ducts damaged by fibrosis, more frequently in calcifying chronic pancreatitis. LTBP was present predominantly in mononuclear cells and in the extracellular matrix around them. TGF-beta 1 mRNA was either not expressed or was faintly expressed in normal tissue, whereas intense signals were detected in chronic pancreatitis. The findings suggest the involvement of TGF-beta 1 in the development of fibrosis in chronic pancreatitis and the important role of inflammatory cells.