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Pancreatic ductal myofibroblasts. Proliferative patterns in various pathologic situations
1Department of Internal Medicine, Jikei University, School of Medicine, Tokyo, Japan. motoyosh@qj8.so-net.ne.jp
Abstract:
Myofibroblasts in the periacinar area of the pancreas have been demonstrated to mediate fibrogenesis in pancreatic fibrosis. However, only a few reports have described myofibroblasts in the pancreatic duct. To elucidate the presence of myofibroblasts in the pancreatic ductal wall, we performed an immunohistochemical study, using immunostains for both alpha-smooth muscle actin (alphaSMA) and desmin, and an electron microscopic study on surgically resected pancreatic specimens from 10, 23, 23, and 56 cases of focal pancreatitis (FP), chronic pancreatitis (CP), pancreatic carcinoma (PCa), and carcinoma of the papilla of Vater (VPCa), respectively. All cases showed localized stenosis of the main pancreatic duct by means of preoperative pancreatography. As controls, 20 autopsy cases were studied. alphaSMA-positive and desmin-negative cells existed in the ductal walls of controls and were revealed as myofibroblasts by means of electron microscopy. In six FPs, proliferation of myofibroblasts was observed at the stenotic portion. In VPCas, myofibroblasts mainly proliferated in the pancreatic ductal wall. In CPs and PCas, no myofibroblast proliferation was observed at the stenotic portion. The proliferation of myofibroblasts might occur as a wound healing process in FP, while acting against elevation of intraductal pressure in VPCa. In conclusion, proliferation of myofibroblasts plays an important role in ductal changes in various pathological situations.
Insights
Myofibroblast proliferation in pancreatic ducts is linked to focal pancreatitis and Vater papilla carcinoma, potentially as a wound healing response or to manage intraductal pressure. This study clarifies their role in pancreatic ductal changes.
Area of Science:
- Gastroenterology
- Surgical Pathology
- Cell Biology
Background:
- Myofibroblasts in the pancreatic periacinar area are known contributors to fibrogenesis in pancreatic fibrosis.
- Limited research has explored the presence and role of myofibroblasts within the pancreatic ductal wall.
Purpose of the Study:
- To investigate the presence and proliferation of myofibroblasts in the pancreatic ductal wall across various pancreatic pathologies.
- To differentiate the role of myofibroblasts in focal pancreatitis, chronic pancreatitis, pancreatic carcinoma, and Vater papilla carcinoma.
Main Methods:
- Immunohistochemical analysis using alpha-smooth muscle actin (alphaSMA) and desmin on surgically resected pancreatic specimens.
- Electron microscopy to confirm cell identity.
- Study included cases of focal pancreatitis (FP), chronic pancreatitis (CP), pancreatic carcinoma (PCa), and carcinoma of the papilla of Vater (VPCa), with autopsy cases as controls.
Main Results:
- AlphaSMA-positive, desmin-negative cells, identified as myofibroblasts, were present in control pancreatic ductal walls.
- Myofibroblast proliferation was observed in the stenotic portions of the main pancreatic duct in six cases of focal pancreatitis.
- Myofibroblast proliferation was prominent in the ductal walls of Vater papilla carcinoma cases, but not observed in chronic pancreatitis or pancreatic carcinoma at the stenotic portion.
Conclusions:
- Myofibroblast proliferation in pancreatic ducts may represent a wound healing response in focal pancreatitis.
- In Vater papilla carcinoma, myofibroblast proliferation might serve to counteract elevated intraductal pressure.
- The study concludes that myofibroblast proliferation is significant in altering pancreatic ductal morphology in diverse pathological conditions.