Hayato Nakamura

Pancreatic cancer complicated by disseminated intravascular coagulation associated with production of tissue factor

A 54-year-old man was diagnosed as having pancreatic cancer and disseminated intravascular coagulation. His plasma tissue factor level on the 11th hospital day was 996 pg/ml (normal range, 120-270 pg/ml). He was treated with gabexate mesilate, antithrombin III, and low-molecular-weight heparin. However, he died of multiple organ failure on the 17th hospital day. The histological finding was poorly differentiated ductal adenocarcinoma of the pancreas, and the production of tissue factor in this lesion was revealed. Tissue factor is a factor that initiates blood coagulation; thus, its expression in pancreatic cancer is one of the causes of coagulation abnormalities in this disease. Although one report has demonstrated immunoreactivity for tissue factor in pancreatic cancer, the patients detailed clinical course was not mentioned in that report. This is the first report to prove that pancreatic cancer produced tissue factor in a patient with disseminated intravascular coagulation.

Duodenal ulcer and pancreatitis associated with pancreatic arteriovenous malformation

Arteriovenous malformation (AVM) of the pancreas is a rare condition that may cause severe gastrointestinal bleeding. We describe a 54-year-old man with a 7-year history of recurrent duodenal ulcer due to AVM in the pancreatic head. We recommended pancreatoduodenectomy because of recurrent haemorrhage from the duodenal ulcer, but the patient refused surgery on several occasions. He was admitted to our hospital complaining of severe upper abdominal pain radiating to the back and was diagnosed with acute pancreatitis. He agreed at that stage to the surgical treatment. The resected specimen contained a highly vascular malformation in the pancreatic head and ulceration in the adjacent descending duodenum. Histopathological examination revealed numerous vascular structures with dilated and tortuous vessels in the pancreatic head, confirming the presence of AVM. Moreover, oedema, inflammatory cell infiltration, haemorrhage and necrosis were evident, confirming the presence of acute pancreatitis.

Role of TGF-β1, Extracellular Matrix, and Matrix Metalloproteinase in the Healing Process of the Pancreas After Induction of Acute Necrotizing Pancreatitis Using Arginine in Rats

Introduction Pancreatic tissues are almost completely restored to normal after an attack of acute pancreatitis, once the cause of the disease is removed. Transforming growth factor (TGF)-&bgr; and extracellular matrix (ECM) are known to play an important role in the process of wound healing in pathologic diseases. Tissue repair is a process regulated by a balance between synthesis and degradation of ECM. Aims To elucidate the role of TGF-&bgr;, ECM, and matrix metalloproteinase (MMP) in the process of regeneration occurring after acute necrotizing pancreatitis. Methodology Acute necrotizing pancreatitis was induced by intraperitoneal injection of 500 mg/100 g body weight of L-arginine in male Wistar rats. Expression of TGF-&bgr;1 and ECM messenger RNA (mRNA) was determined by Northern blot analysis, and that of MMP-1 and MMP-2 mRNA was examined by the reverse transcription polymerase chain reaction (RT-PCR). Immunoreactivity for ECM components, TGF-&bgr;1, and MMP-2 in the pancreas was assessed by using a monoclonal antibody. Results TGF-&bgr;1 mRNA expression reached a peak value on day 2.5, with a decrease on day 3, and reached the control level on day 7. Procollagen types III and IV and fibronectin mRNA reached a peak value on day 2.5, whereas the expression level of procollagen type I mRNA was maximal on day 3, and gradually decreased to control levels by day 7. MMP-2 mRNA was significantly elevated on day 3, and peaked on day 5, whereas MMP-1 mRNA levels did not change throughout the observation period. Immunoreactivity for MMP-2 was observed around disrupted acinar cells and interstitial spaces on day 3, and maximally on day 7. Immunoreactivity for fibronectin was detected around disrupted acinar cells and interstitial spaces. On day 7, it was less than on day 5 around disrupted acinar cells and interstitial spaces, whereas in the regenerated acinar cells, it was undetected. Conclusion Our results show that TGF-&bgr;1 mRNA expression peaked earlier than that of ECM mRNA. Furthermore, increased level of the MMP-2 transcript was followed by disappearance of fibronectin. Our findings suggest that TGF-&bgr;1 plays an important role in ECM production in the early phase of acute pancreatitis, and that MMP-2 is involved in the subsequent healing process.

Green tea polyphenol (–)-epigallocatechin-3-gallate inhibits ethanol-induced activation of pancreatic stellate cells

Background  Activated pancreatic stellate cells (PSCs) play a central role in the pathogenesis of pancreatic fibrogenesis and inflammation. Ethanol, a major cause of chronic pancreatitis, directly induces PSC activation and oxidative stress. Inhibition of PSC activation or stimulation to PSC might be an effective therapeutic strategy for the prevention of pancreatic fibrosis, and (–)‐epigallocatechin‐3‐gallate (EGCG), a major component of green tea extracts, is a potent antioxidant of polyphenols. Therefore, we examined the mechanisms through which ethanol induces oxidative stress on PSCs and evaluated the effect of EGCG on activation and cell functions of ethanol‐stimulated PSCs.

High glucose activates rat pancreatic stellate cells through protein kinase C and p38 mitogen-activated protein kinase pathway.

Objective: Hyperglycemia is implicated in fibrosis in many organs. Exocrine and endocrine pancreas are closely linked both anatomically and physiologically, and pathological conditions in the exocrine gland can cause impairment of endocrine function and vice versa. Chronic pancreatitis causes pancreatic fibrosis and sometimes results in diabetes mellitus. Pancreatic stellate cells (PSCs) play a pivotal role in pancreatic fibrogenesis. However, the effects of high glucose concentrations on PSC activation have not been fully elucidated. Methods: Cultured PSCs were incubated in the presence of various concentrations of glucose. Pancreatic stellate cell proliferation, &agr;-smooth muscle actin (&agr;-SMA) expression, and collagen production were determined by colorimetric conversion assay, Western blot analysis, and Sirius red dye binding assay, respectively. Results: High glucose concentrations significantly increased PSC proliferation, &agr;-SMA expression, and collagen type I production in PSCs. High glucose concentrations activated protein kinase C (PKC) in PSCs, and PKC inhibitor GF109203X inhibited glucose-stimulated PSC proliferation, &agr;-SMA expression, and collagen secretion. High glucose also activated p38 mitogen-activated protein kinase (MAPK) in PSCs, and p38 MAPK inhibitor SB203580 inhibited glucose-stimulated collagen secretion. Conclusions: Our results indicate that high glucose concentrations stimulate PSC activation via PKC-p38 MAP kinase pathway and suggest that high glucose may aggravate pancreatic fibrosis.

Defects of cholecystokinin (CCK)-A receptor gene expression and CCK-A receptor-mediated biological functions in Otsuka Long-Evans Tokushima Fatty (OLETF) rats.

Abstract: Recent studies in genetically obese and diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats suggest defects of cholecystokinin (CCK)-A receptor gene expression and CCK-A receptor-mediated biological functions such as pancreatic juice, protein, and gastric acid secretion. The present studies were undertaken to further examine CCK-A receptor gene expression and CCK-A receptor-mediated biological functions in the pancreas, stomach, and brain of OLETF rats. Expression of the CCK-A receptor gene could not be detected in the stomach, pancreas and brain by the reverse-transcription polymerase chain reaction (RT-PCR) method and Southern blotting of the PCR products. Southern blot analysis of genomic DNA from OLETF and control Long-Evans Tokushima Otsuka (LETO) rats with CCK-A receptor fragment as a probe revealed different restriction bands. Expression of the CCK-B receptor gene was observed in the stomach, pancreas, and brain in both OLETF and LETO rats by the RT-PCR method, with expression of the CCK-B receptor gene markedly enhanced in OLETF rats compared with that in LETO rats. Consistent with the defect of CCK-A receptor gene expression, CCK-A receptor-mediated biological functions were not observed in these organs. Perfused exocrine and endocrine pancreas of OLETF rats were insensitive to CCK stimulation but not to carbamylcholine stimulation. Basal gastric acid and pepsinogen secretions in OLETF rats were higher than in LETO rats. OLETF rats showed a significantly higher average daily food intake, gained body weight faster, and were heavier than LETO rats. The present study confirmed that OLETF rats have CCK-A receptor gene anomalies and demonstrated deficient CCK-A receptor-mediated biological function in the pancreas, stomach, and brain.

Persistent destruction of the basement membrane of the pancreatic duct contributes to progressive acinar atrophy in rats with experimentally-induced pancreatitis

Background and Aims: The imbalance between synthesis and degradation of extracellular matrix (ECM) proteins is a characteristic feature in chronic pancreatitis. We evaluated the relationship between type IV collagen structure in the basement membrane (BM) and the development of acinar atrophy or the regeneration from acinar injury. Methods: Three different models of pancreatitis were induced in rats by repetitive intraperitoneal injections of 500 mg/100 g body weight of arginine (Arg) or 20 μg/kg body weight of caerulein (Cn) or a single retrograde intraductal infusion of 40 μL/100 g body weight of 3% sodium taurocholate (NaTc). We examined the changes in type IV collagen structure by immunostaining, and the serial changes in the gelatinolytic activity of pro- and active matrix metalloproteinase-2 by zymography in these models of pancreatitis. Results: The pancreas appeared to be histologically normal on day 35 after the first intraperitoneal Cn injection and on day 42 after intraductal infusion of NaTc, whereas 85% to 90% of acinar tissue was replaced by fatty tissue and dilated pancreatic ducts on day 54 after the first intraperitoneal Arg injection. Immunoreactivity for type IV collagen appeared as a discontinuous line along the BM of ducts, vessels, tubular complexes, and acinar cells on day 40 in Arg-induced pancreatitis, whereas it was detected as a continuous line along the BM on day 35 in Cn-induced pancreatitis and on day 42 in NaTc-induced pancreatitits. Gelatinolytic activity of active MMP-2 increased significantly from day 13 to day 40 after the first intraperitoneal Arg injection, whereas it decreased to the baseline level on day 35 after the first intraperitoneal Cn injection and on day 42 after intraductal infusion of NaTc. Conclusions: Our findings indicate that a long-term increase in gelatinolytic activity of active MMP-2 in Arg-induced pancreatitis causes continuous disorganization of type IV collagen in the BM and progressive acinar atrophy, whereas a transient increase in gelatinolytic activity of active MMP-2 is involved in the regeneration of type IV collagen structure in the BM and recovery from acinar injury.

The Elongated PAP II/Reg III mRNA is Upregulated in Rat Pancreas During Acute Experimental Pancreatitis

Introduction The pathogenesis and the mechanism of the development of severe acute pancreatitis are not clearly understood. Aims We performed differential display analysis to find genes that show transcriptional changes in the pancreas during the development of severe acute pancreatitis in the rat. Methodology Twenty candidate pancreatitis-associated complementary DNA (cDNA) fragments were isolated. cDNA sequencing and subsequent database analysis revealed that one fragment (C18-2) among the 20 cDNA fragments showed no significant sequence similarity to previously reported genes, suggesting that it represented a novel gene. The rapid and high expression of C18-2 during the acute phase of pancreatitis suggested that the gene was involved in the development of acute pancreatitis. Therefore, we used rapid amplification of cDNA ends and identified the full-length cDNA. Results Analysis of the open reading frame of the cDNA indicated that the deduced protein from the messenger RNA (mRNA) was a polypeptide of 174 amino acids, unexpectedly similar to that of a known gene, rat pancreatitis–associated protein II/regenerating gene III (PAP II/Reg III). However, the length of the identified mRNA (1,467 base pairs) was longer than that of rat PAP II mRNA (885 base pairs), because the elongated mRNA was generated through the different polyadenylation site in the same gene. The elongated mRNA after acute pancreatitis was strongly induced in the restricted early phase, in comparison with the original mRNA. Conclusion It is considered that the elongated mRNA affects the function of PAP II/Reg III protein because the elongated mRNA with long 3´ untranslated regions is known to be involved in the translation efficiency. The identified mRNA may play an important role in the progression of pancreatitis.

Long-term Overexpression of Membrane Type-1 Matrix Metalloproteinase and Matrix Metalloproteinase-2 in Oleic Acid-induced Pancreatitis in Rats

Introduction The matrix metalloproteinase (MMP) plays important roles in extracellular matrix turnover. However, little is known about the roles of MMP-2 and type IV collagen, and the relationship between MMP-2 and membrane type-1 matrix metalloproteinase (MT1-MMP) during progressive destruction of acinar cells in pancreatitis. Aims and Methodology To examine the serial changes in the expression and activity of MMP-2 and expression of MT1-MMP and tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) in rats after induction of pancreatitis by intraductal infusion of oleic acid, and to determine protein concentrations by Western blot analysis and localization of type IV collagen by immunostaining. Results Gelatinolytic activity of pro-and active MMP-2 and concentrations of MT1-MMP protein, as determined by zymography and Western blot analysis, respectively, increased significantly from 6 hours to day 42 after intraductal infusion of oleic acid. TIMP-2 mRNA expression was significantly higher than that at time 0 throughout the study period, and gelatinolytic activity of active MMP-2 increased from day 3 to day 42. In addition, immunoreactivity for type IV collagen was detected as a discontinuous line along the basement membranes of ducts, vessels, tubular complexes, and acinar cells. Conclusion Our findings indicate that long-term increases of gelatinolytic activity of active MMP-2 cause continuous disorganization of type IV collagen in basement membranes during progressive atrophy of pancreatic gland in oleic acid–induced pancreatitis, and that MT1-MMP and TIMP-2 work as activating factors during proMMP-2 activation. Moreover, basement membranes disorganization in the sustentacula of acinar cells and duct epithelia seems to participate in continuous derangement of acinar cells and duct epithelium.

Oleic acid-induced Pancreatitis alters expression of transforming growth factor-β1 and Extracellular matrix components in rats

Introduction and Aims Extracellular matrix (ECM) components participate in the process of tissue repair and development of fibrosis in the pancreas. We studied the production kinetics of ECM components and transforming growth factor (TGF)–&bgr;1 and identified their production sites in the pancreas following pancreatitis. Methodology Pancreatitis was induced in rats by a single intraductal infusion of oleic acid. Gene expression of TGF-&bgr;s and ECM components was studied by northern blotting. Pancreatic stellate cell activation was assessed by immunostaining for &agr;-smooth muscle actin (&agr;SMA) and desmin. Results Gene expression of TGF-&bgr;s and ECM components was increased in association with pancreatic fibrosis after 1–2 weeks and remained higher than the control levels for the ensuing 12 weeks. Both &agr;SMA and desmin were strongly immunostained around small vessels and faintly stained in mesenchymal cells and tubular complexes at 1 week. The combination of staining for &agr;SMA plus in situ hybridization for procollagen type III mRNA revealed that procollagen type III mRNA was expressed in both &agr;SMA-positive and &agr;SMA-negative cells in the mesenchyma. Conclusions Our findings demonstrate that expression of genes for both TGF-&bgr;s and ECM components was increased and that both &agr;SMA-positive myofibroblasts and mesenchymal cells are the major sources of ECM components after pancreatitis.