Synthesis and localization of pancreatic secretory proteins in pancreatic acinar-like metaplasia in the distal part of the oesophagus

Background: Pancreatic acinar-like metaplasia has previously been described in the gastric mucosa and in the distal part of the oesophagus. The resemblance to pancreatic acinar cells prompted us to study the possible occurrence of secretory pancreatic proteins in these cells. Methods: Seven specimens obtained from the distal oesophagus at gastroscopy where routine microscopy showed pancreatic acinar-like metaplasia were selected for this study. Sections were subjected to immunohistochemical detection of trypsinogen, pancreatic elastase, procarboxypeptidase B and pancreatic secretory trypsin inhibitor using specific antisera. An alkaline-phosphatase-conjugated oligodeoxynucleotide probe, complementary to the transcript for trypsinogen 2 (anionic) was used for in situ hybridization. Results: Cells with pancreatic acinar-like metaplasia were immunoreactive to all pancreatic secretory proteins studied. In situ hybridization showed the presence of trypsinogen 2 mRNA in pancreatic acinar-like metaplasia. The pancreatic proteins were not seen in other cells in the distal oesophagus. Conclusion: Pancreatic acinar-like metaplasia is common in the distal oesophagus and pancreatic secretory proteins, including trypsininogen 2, are produced in the oesophageal metaplastic acinar cells. The biological significance of this finding has yet not been thoroughly studied.