Multiple factors influencing the release of hTERT mRNA from pancreatic cancer cell lines in in vitro culture.

Since telomerase expression is highly prevalent in human cancers, the quantitation of serum/plasma hTERT (human telomerase reverse transcriptase) mRNA levels may be useful for early detection of PCa (pancreatic cancer). To analyse the correspondence between exhTERT (extracellular hTERT) mRNA levels and hTERT expression, we designed a cell culture system to investigate factors modulating the extracellular levels of hTERT mRNA in media conditioned by eight PCa cell lines. We found that the level of exhTERT mRNA was dependent on cell growth rate. MIAPaCa-2, PANC-1, KLM-1 and PK-9 cells expressed high levels of exhTERT mRNA, independent of cell density, whereas proliferating PK-59, BxPC-3 and PK-45H cells released low levels of exhTERT mRNA. The augmented release of mRNA by spontaneous dead MIAPaCa-2 cells was further increased at postconfluence. In Capan-1 cells, low correspondence of marker was also due to RNase secretion. Upon reaching confluence, some PCa cell lines showed down-regulation of hTERT expression. Following cell-cell adhesion, as shown by E-cadherin engagement, PK-59 cells showed levels of extracellular message below the limits of detection, a loss not due to an increase in message degradation. These results suggest that the levels of exhTERT mRNA in the medium of PCa cell lines are altered not only in response to cell growth rate and cell destruction, but are responsive to extracellular cues such as RNases and cell density. A cell-free assay for exhTERT mRNA may therefore not be useful for early detection of PCa.

Advanced hepatocellular carcinoma treated effectively with irinotecan via hepatic arterial infusion followed by proton beam therapy.

We report a 48-year-old man with hepatocellular carcinoma (HCC) treated with hepatic arterial infusion (HAI) chemotherapy followed by proton beam therapy. The HCC lesion in this patient was 88 mm in diameter, with portal vein tumor thrombosis in the right lobe of the liver. He was first treated with 5-fluorouracil, cisplatin, and isovorin, administered by HAI, combined with interferon-alpha, and he was subsequently treated with epirubicin and mitomycin-C administered by HAI. However, no definite efficacy of either of these treatments was observed. Then, after 3 weeks' continuous administration of irinotecan by HAI, the tumor size decreased to 68 mm in diameter. However, 3 months after reduction of the tumor, the tumor had become enlarged to 100 mm in diameter and intrahepatic metastases were prominent. Angiographic findings indicated that the HCC was fed not only from the right hepatic artery but also from the left gastric and right and left subphrenic arteries. After rearrangement of the arteries, and 3 months' continuous HAI chemotherapy with irinotecan, plus hyperthermia, the tumor size had decreased to 50 mm in diameter. The reduction rate of the main tumor according to the Response Evaluation Criteria in Solid Tumors was 43%; therefore, the efficacy of this treatment was judged as a partial response. Two months after reduction of the tumor, the patient's serum alpha-fetoprotein (AFP) level was elevated, and so docetaxel was administered by HAI instead of irinotecan. The liver tumors showed gradual enlargement during the administration of docetaxel, although the AFP level was suppressed. Proton beam therapy was instituted and the liver tumors showed necrosis after this therapy. The patient died of hepatic failure and distant metastases 6 years after the onset of HCC. As far as we know, this is the first case report of HCC treated effectively with irinotecan administered by HAI followed by proton beam therapy in which tumor suppression and the long-term survival of the patient were observed.

Appropriate steroid therapy for autoimmune pancreatitis based on long-term outcome.

OBJECTIVE: Because autoimmune pancreatitis (AIP) responds well to corticosteroids, many AIP patients are given this treatment. However, there is no consensus on the indications, dose, or duration of steroid treatment. The aim of this study was to establish the most appropriate steroid therapy regimen. MATERIAL AND METHODS: We retrospectively reviewed morphological and serological improvement after steroid therapy and long-term outcome including relapse in 41 AIP patients who were given steroid therapy and were prospectively followed-up for more than 1 year. RESULTS: All patients responded to steroid therapy, which was given because of bile duct stenosis secondary to sclerosing cholangitis in 34 AIP patients. Pancreatic enlargement normalized within one month; however, 13 patients had incomplete resolution of pancreatic duct narrowing, and 14 patients had incomplete resolution of bile duct stenosis. There was no correlation between the degree of morphological improvement and the initial prednisolone dose (30 mg and 40 mg/day). In 58% of 19 patients, serum IgG4 elevation failed to normalize. Glucose intolerance improved in 38% of the 21 patients with diabetes mellitus. Nine patients who had complete morphological and serological resolution, stopped their medication, and none have relapsed. Thirty-two patients continued maintenance therapy, and 4 of these patients suffered relapse. CONCLUSIONS: The indications for steroid therapy in AIP patients include bile duct stenosis caused by sclerosing cholangitis and other systemic diseases, such as retroperitoneal fibrosis and diabetes mellitus. We recommend that oral prednisolone be used at an initial dose of 30 mg/day; maintenance therapy is required in cases without complete morphological and serological resolution.

A case of pancreatic cancer with formation of a mass mimicking alcoholic or autoimmune pancreatitis in a young man. Possibility of diagnosis by hypermethylation of pure pancreatic juice.

CONTEXT: Mass-forming pancreatitis can be divided into two distinct types: alcoholic and autoimmune. There have been some cases of an ambiguous diagnosis although care was taken to differentiate between alcoholic mass-forming pancreatitis, focal type autoimmune pancreatitis and pancreatic cancer. CASE REPORT: We report a case of pancreatic cancer mimicking alcoholic or autoimmune pancreatitis with the formation of a mass in a 32-year-old man with a history of heavy drinking. Although both serum immunoglobulin G and immunoglobulin G4 levels were normal, many serum auto-antibodies, including the antinuclear antibody, were detected. After he stopped drinking, abdominal computed tomography showed a pancreatic head mass 28 mm in diameter with little and weak enhancement in the early and delayed phases, respectively. Endoscopic retrograde cholangiopancreatography showed an obstruction of the main pancreatic duct in the pancreatic head and marked stenosis of the lower common bile duct. Although a percutaneous ultrasound-guided pancreatic biopsy demonstrated no evidence of autoimmune pancreatitis, he was treated with prednisolone to test the efficacy of steroid therapy. However, the pancreatic mass became enlarged after steroid therapy, and he underwent surgery during which the mass was found to be pancreatic cancer. Although the patient was treated with gemcitabine, he died 5 months after surgery. We retrospectively assessed DNA hypermethylation in the patient's pure pancreatic juice obtained on admission. We observed hypermethylation of the cancer-specific gene tissue factor pathway inhibitor 2 (TFPI2). CONCLUSION: This finding suggests that if the DNA hypermethylation of pure pancreatic juice had been assayed before steroid therapy, it would have supported the diagnosis of pancreatic cancer, and steroid therapy could have been avoided.

A case of autoimmune pancreatitis associated with retroperitoneal fibrosis.

CONTEXT: Autoimmune pancreatitis is characterized by diffuse enlargement of the pancreas, diffuse irregular narrowing of the main pancreatic duct, severe lymphoplasmacytic infiltration and fibrosis of the pancreas. Retroperitoneal fibrosis may occasionally be associated with autoimmune pancreatitis. CASE REPORT: We report a 77-year-old man with autoimmune pancreatitis associated with retroperitoneal fibrosis. Abdominal ultrasonography and computed tomography demonstrated diffuse enlargement of the pancreas and a capsule-like rim. Furthermore, a retroperitoneal mass was recognized anterior to the abdominal aorta. Antinuclear antibody, IgG and IgG4 values were elevated. Therefore, this patient was diagnosed as having autoimmune pancreatitis associated with retroperitoneal fibrosis. We performed steroid therapy using prednisolone. After 4 weeks, both IgG and IgG4 values decreased and both the swelling of the pancreas and also the retroperitoneal mass were obviously diminished. CONCLUSION: This is a rare case of autoimmune pancreatitis associated with retroperitoneal fibrosis.

Preproenkephalin hypermethylation in the pure pancreatic juice compared with p53 mutation in the diagnosis of pancreatic carcinoma.

BACKGROUND: Aberrant methylation of CpG islands is a common mechanism for the dysregulation of tumor suppressor genes in a variety of human malignancies. Preproenkephalin ppENK) hypermethylation is recognized in 90% of pancreatic carcinoma (PCa) tissues, but not in normal pancreas. We analyzed ppENK hypermethylation in pure pancreatic juice (PPJ) in patients with PCa, intraductal papillary mucinous neoplasms (IPMN), and chronic pancreatitis (CP), and elucidated its usefulness as a marker in the diagnosis of PCa compared with p53 mutation. METHODS: PPJ was collected endoscopically from 28 patients with PCa, 15 patients with IPMN, and 20 patients with CP. DNA was extracted from the supernatant and the sediment of PPJ. Methylation-specific polymerase chain reaction was performed for hypermethylation analysis of ppENK. In addition, single-strand conformation polymorphism and direct sequencing were performed simultaneously to identify p53 mutations. RESULTS: The incidence of ppENK hypermethylation in the supernatant and/or the sediment of PPJ was 50% (14 of 28) in patients with PCa. In contrast, the incidence of ppENK hypermethylation was 26.7% (4 of 15) in patients with IPMN, and 5% (1 of 20) in patients with CP (P < 0.002). The incidence of p53 mutations in the PPJ was 42.9% (12 of 28) in patients with PCa and 0% (0 of 20) in patients with CP. Furthermore, the incidence of ppENK hypermethylation and/or p53 mutations in the PPJ was enhanced to 67.9% (19 of 28) in patients with PCa in the combination assay. CONCLUSIONS: These results suggest that ppENK hypermethylation in PPJ is specific for cancer, and the combination assay with p53 enhances the genetic diagnosis of PCa.

Effect of gemcitabine on the expression of apoptosis-related genes in human pancreatic cancer cells.

AIM: To investigate the expression of genes involved in the gemcitabine-induced cytotoxicity in human pancreatic cancer cells. METHODS: A human pancreatic cancer cell line, PANC-1, was cultured. 1x10(4) PANC-1 cells were plated in 96-well microtiter plates. After being incubated for 24 h, gemcitabine was added to the medium at concentrations ranging 2.5-1000 mg/L. The AlamarBlue dye method was used for cell growth analysis. DNA fragmentation was quantitatively assayed using a DNA fragmentation enzyme-linked immunosorbent assay (ELISA) kit. PAP and TP53INP1 mRNA expression was determined using the reverse transcription-polymerase chain reaction with semi-quantitative analysis. The expression of GSK-3beta and phospho-GSK-3beta proteins was examined with Western blot analysis. RESULTS: The IC50 for the drug after a 48-h exposure to gemcitabine was 16 mg/L. The growth of PANC-1 cells was inhibited by gemcitabine in a concentration-dependent manner (P<0.0001) and the cell growth was also inhibited throughout the time course (P<0.0001). The DNA fragmentation rate in the gemcitabine-treated group at 48 h was 44.7%, whereas it was 25.3% in the untreated group. The PAP mRNA expression was decreased after being treated with gemcitabine, whereas the TP53INP1 mRNA was increased by the gemcitabine treatment. Western blot analysis showed that phospho- GSK-3beta (ser9) was induced by the gemcitabine treatment. CONCLUSION: Gemcitabine suppresses PANC-1 cell proliferation and induces apoptosis. Apoptosis is considered to be associated with the inhibition of PAP and GSK-3beta, and the activation of TP53INP1 and pospho-GSK-3beta (ser9).

Down-expression of tumor protein p53-induced nuclear protein 1 in human gastric cancer.

AIM: Overexpression of tumor protein p53-induced nuclear protein 1 (TP53INP1) induces G1 cell cycle arrest and increases p53-mediated apoptosis. To clarify the clinical importance of TP53INP1, we analyzed TP53INP1 and p53 expression in gastric cancer. METHODS: TP53INP1 and p53 expression were examined using immunohistochemistry in 142 cases of gastric cancer. The apoptosis of gastric cancer cells was analyzed using the TUNEL method. The relationship between the expression of TP53INP1 and clinicopathological factors was statistically analyzed. RESULTS: TP53INP1 was expressed in 98% (139/142 cases) of non-cancerous gastric tissues and was down-expressed in 64% (91/142 cases) of gastric cancer lesions from the same patients. TP53INP1 expression was significantly decreased (43.9%) in poorly differentiated adenocarcinoma compared with well or moderately differentiated adenocarcinoma (81.6%). Cancers invading the submucosa or deeper showed lower positively (59.1%) compared with mucosal cancers (85.2%). Decrease or loss of TP53INP1 expression was significantly correlated with lymphatic invasion (54.3% vs 82.0% without lymphatic invasion) and node-positive patients (31.3% vs 68.3% in node-negative patients). P53 was expressed in 68 (47.9%) patients of gastric cancer, whereas it was absent in normal gastric tissues. A significant association was also observed between TP53INP1 status and the level of apoptosis in tumor cells: the apoptotic index in TP53INP1-positive tissues was significantly higher than that in TP53INP1-negative portions. Finally, when survival data were analyzed, loss of TP53INP1 expression had a significant effect in predicting a poor prognosis (P=0.0006). CONCLUSION: TP53INP1-positive rate decreases with the progression of gastric cancer. TP53INP1 protein negativity is significantly associated with aggressive pathological phenotypes of gastric cancer. TP53INP1 is related to the apoptosis of gastric cancer cells. The decreased expression of the TP53INP1 protein may reflect the malignant grade of gastric cancer and is regarded as an adverse prognostic factor.

Consensus of primary care in acute pancreatitis in Japan.

The incidence of acute pancreatitis in Japan is increasing and ranges from 187 to 347 cases per million populations. Case fatality was 0.2% for mild to moderate, and 9.0% for severe acute pancreatitis in Japan in 2003. Experts in pancreatitis in Japan made this document focusing on the practical aspects in the early management of patients with acute pancreatitis. The correct diagnosis of acute pancreatitis and severity stratification should be made in all patients using the criteria for the diagnosis of acute pancreatitis and the multifactor scoring system proposed by the Research Committee of Intractable Diseases of the Pancreas as early as possible. All patients diagnosed with acute pancreatitis should be managed in the hospital. Monitoring of blood pressure, pulse and respiratory rate, body temperature, hourly urinary volume, and blood oxygen saturation level is essential in the management of such patients. Early vigorous intravenous hydration is of foremost importance to stabilize circulatory dynamics. Adequate pain relief with opiates is also important. In severe acute pancreatitis, prophylactic intravenous administration of antibiotics at an early stage is recommended. Administration of protease inhibitors should be initiated as soon as the diagnosis of acute pancreatitis is confirmed. A combination of enteral feeding with parenteral nutrition from early stage is recommended if there are no clear signs and symptoms of ileus and gastrointestinal bleeding. Patients with severe acute pancreatitis should be transferred to ICU as early as possible to perform special measures such as continuous regional arterial infusion of protease inhibitors and antibiotics, and continuous hemodiafiltration. The Japanese Government covers medical care expense for severe acute pancreatitis as one of the projects of Research on Measures for Intractable Diseases.

Herbal medicine Ninjinyoeito ameliorates ribavirin-induced anemia in chronic hepatitis C: a randomized controlled trial.

AIM: Ribavirin (RBV) shows a strong antiviral effect on hepatitis C virus when used in combination with interferon. However, RBV-induced anemia is a major problem in this therapy. It would be of great clinical importance to ameliorate the anemia without reducing the RBV dose. We report here that, Ninjinyoeito (NYT), a herbal medicine can reduce the RBV-induced anemia. METHODS: Twenty-three patients with chronic hepatitis C were treated with interferon alpha 2b plus RBV with (NYT group) or without (control group) NYT by a randomized selection. Eighteen patients completed the treatment schedule, and hemato-biochemical and virological effects were evaluated. RESULTS: There was no significant difference in biochemical and virological responses between the two groups. However, anemia was significantly reduced in the NYT group compared with the control group. The maximal decrease of Hb in the NYT group (2.59+/-1.10 g/dL) was significantly (P = 0.026) smaller than that in the control group (3.71+/-0.97 g/dL). There was no significant difference in serum glutathione peroxidase activity, serum RBV concentration, and Th1/Th2 balance between the two groups. There was no specific adverse effect in NYT administration. CONCLUSION: These results suggest that NYT could be used as a supportive remedy to reduce the RBV-induced anemia in the treatment of chronic hepatitis C.

Superoxide dismutase is induced during rat pancreatic acinar cell injury.

INTRODUCTION: Free radicals and their scavengers are supposed to be involved in pancreatitis. AIMS: To investigate the expression of superoxide dismutase (SOD) in rat pancreatic acinar cell injury. METHODOLOGY AND RESULTS: As an in vivo model, male WBN/Kob rats were used. Chronic pancreatitis developed spontaneously at 12 weeks in this model and progressed thereafter, but acinar regeneration was recognized at 20 weeks. By semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), manganese SOD (MnSOD) mRNA expression peaked at 8 and 20 weeks, whereas copper/zinc SOD (CuZnSOD) mRNA expression peaked at 12 and 20 weeks. Immunohistochemistry confirmed the localization of SOD in acinar cells. Acinar cell apoptosis peaked at 12 and 20 weeks. In an in vitro study, MnSOD mRNA expression peaked at 2 hours after the addition of arginine to culture medium, whereas apoptosis was increased at 24 hours. CONCLUSION: Thus, the induction of SOD around the onset and at the late stage of chronic pancreatitis in the WBN/Kob rats implies pancreatic ischemia and acinar remodeling, respectively. From the in vitro results, MnSOD expression might reflect a defensive mechanism of acinar cells against oxidative stress or pro-apoptotic stimuli.

Induction of chemokines in rat pancreatic acinar cell injury.

INTRODUCTION: The pathogenesis of chronic pancreatitis (CP), especially of acinar cell injury, is still unclear. Interleukin (IL)-8 is a chemokine that is involved in various inflammatory diseases. AIM: To examine whether IL-8 and other chemokines are expressed in experimental acinar cell injury. METHODOLOGY: IL-8 expression was analyzed in spontaneous CP in the WBN/Kob rat and in rat pancreatic acinar AR4-2J cells treated with various stimuli using reverse transcription-polymerase chain reaction (semiquantitative) and immunohistochemistry. RESULTS: Chronic pancreatitis developed at 12 weeks in the WBN/Kob rats. IL-8, macrophage chemoattractant protein-1, and macrophage inflammatory protein-2 mRNA was expressed from 4 weeks and peaked at 12 weeks. Immunohistochemistry showed a strong expression of IL-8 in acinar cells, proliferating ductular cells, and interstitial infiltrating cells. In contrast, normal pancreatic tissues lacked IL-8 expression. Further, IL-8 mRNA and protein were detectable in AR4-2J cells treated with the various stimuli, such as menadione, tumor necrosis factor-alpha and transforming growth factor beta1. CONCLUSION: These results suggest that IL-8 is expressed in the pancreatic parenchyma and infiltrates in CP and that it plays a role in the initial pathogenesis of CP together with other chemokines and cytokines.

Abnormalities of tumor suppressor gene p16 in pancreatic carcinoma: immunohistochemical and genetic findings compared with clinicopathological parameters.

BACKGROUND: Abnormalities of the tumor suppressor gene p16 have been reported in a variety of human tumors but are rare in pancreatic carcinoma except for cancer cell lines and xenografts. Their clinicopathological significance remains unknown. The purpose of this study was to examine immunohistochemical and genetic alterations of p16 in primary pancreatic carcinoma tissues and to investigate the relation between abnormalities of p16 and clinicopathological parameters to elucidate their clinicopathological significance. METHODS: We investigated p16 expression in 60 pancreatic carcinoma cases by immunohistochemistry using a monoclonal antibody clone G175-405. In addition, we analyzed genetic alterations of the p16 gene using DNA extracted from microdissected tissue of pancreatic carcinoma, by polymerase chain reaction, nonradioisotopic single-strand conformation polymorphism (non-RI-SSCP), DNA sequencing, and hypermethylation analyses using restriction enzymes. We compared the abnormalities of p16 alterations with clinicopathological parameters to elucidate their significance. RESULTS: On immunohistochemical study, staining for p16 protein was strongly positive in 22 (37%) of 60 pancreatic carcinoma cases, weakly positive in 24 (40%), and negative in 14 (23%). In contrast, p16 mutations were recognized in 9 (15%) of the 60 pancreatic carcinoma cases. The incidence of p16 mutations was 2 (9%) in 22 cases of pancreatic carcinoma with strongly positive staining, 4 (17%) in 24 with weakly positive staining, and 3 (21%) in 14 with negative staining. Hypermethylation of p16 was detected in the two pancreatic carcinoma cases with weakly positive staining, although homozygous deletions were not found in any case. There was no significant correlation between the expression of p16 protein and any of the clinicopathological parameters. However, there was a tendency for the tumor to be larger in patients with decreased expression of p16 protein than in those with normal expression levels. In contrast, the tumor was significantly larger and the survival period significantly shorter for patients with pancreatic carcinoma with p16 mutation or hypermethylation than for those with pancreatic carcinoma with an intact p16 gene (P < 0.05). CONCLUSIONS: These findings suggest that p16 alterations may participate in the aggressiveness of pancreatic carcinoma.

Usefulness of p53 gene mutations in the supernatant of bile for diagnosis of biliary tract carcinoma: comparison with K- ras mutation.

BACKGROUND: The sensitivity of bile cytology for the diagnosis of biliary tract carcinoma (BTCa) is still low. In addition, the incidence of detection of genetic mutations in the bile of BTCa is not satisfactory yet. To improve the molecular diagnosis of BTCa, we analyzed p53 and K- ras mutations in DNA extracted from not only the sediment but the supernatant of bile samples. METHODS: Polymerase chain reaction-single-strand conformation polymorphism and direct sequencing were used for analyses of p53 mutations in exons 5 through 8. K- ras mutations at codon 12 were examined by mutant allele-specific amplification. RESULTS: In bile supernatant from patients with BTCa, p53 and K- ras mutations were detected in 50.0% (15/30) and 56.7% (17/30) of cases, respectively. The incidence of p53and K- ras mutations in the sediment was 33.3% and 43.3%, respectively. When a combination assay with both genes was used, molecular abnormalities were detected in 80.0% of cases, including 3 in which p53 alone was positive. In addition, either p53 or K- rasmutations were detected in 12 of 15 (80.0%) cases of BTCa in which the cytologic diagnoses were negative. p53 mutations were detected in neither supernatant nor sediment in 20 patients with cholelithiasis, although the incidence of K- ras mutations in the sediment was 20%. CONCLUSIONS: The incidence of p53 and K- ras mutations is higher in the supernatant than in the sediment, and simultaneous analyses of p53 and K- ras in the two bile fractions could enhance the genetic diagnosis of BTCa. Notably, the specificity of p53 mutations for cancer was very high in bile samples, and the sensitivity was also relatively high.

Expression of interleukin-8 in human obstructive pancreatitis.

CONTEXT: Obstructive pancreatitis is a specific form of pancreatitis, which is caused by the obstruction of the main pancreatic duct due to tumors or some other causes. Interleukin-8 is induced in acute pancreatitis, but its expression in obstructive pancreatitis has not been clarified. OBJECTIVE: We attempted to provide some insight into the significance of interleukin -8 in the pathogenesis of pancreatic fibrosis. PATIENTS: Fifteen cases of pancreatic cancer, 7 cases of mucinous cystadenoma, 3 cases of Vater's papilla cancer and 9 normal pancreases were included in this study. MAIN OUTCOME MEASURES: The obstructive pancreatitis portions of the above pathologies were evaluated for interleukin-8 expression by means of immunohistochemistry and in situ hybridization. RESULTS: Interleukin-8 was positive in 72% of cases of obstructive pancreatitis. The positive rate was not significantly related to the etiology of the obstruction (P=0.972). Interleukin-8 was expressed in infiltrating cells, proliferating ductular cells and acinar cells. In contrast, normal pancreases and tumor cells lacked interleukin-8 expression (P<0.001 vs. obstructive pancreatitis). Both immunohistochemistry and in situ hybridization demonstrated that interleukin-8 was expressed mostly in acinar cells in mild pancreatic fibrosis, whereas it was expressed in stromal and ductular cells in moderate and severe pancreatic fibrosis. CONCLUSIONS: These results suggest that interleukin-8 expression is related to the fibrotic process in obstructive pancreatitis.

Tumor protein p53-induced nuclear protein 1 (TP53INP1) in spontaneous chronic pancreatitis in the WBN/Kob rat: drug effects on its expression in the pancreas.

CONTEXT: The tumor protein p53-induced nuclear protein 1 (TP53INP1) gene was found using DNA microarray technology as an overexpressed gene in acute pancreatitis. However, expression of TP53INP1 in chronic pancreatitis has not been previously reported. OBJECTIVE: This study investigated TP53INP1 gene expression and its relationship with p53 and apoptosis in spontaneous chronic pancreatitis in the Wistar-Bonn/Kobori rat. METHODS: Ninety four-week-old male Wistar-Bonn/Kobori rats were fed a special breeding diet until sacrifice. Camostat mesilate (n=30) or a herbal medicine (Saiko-keishi-to; n=30) were mixed with the diet, while the other 30 rats were untreated. The rats were sacrificed every 4 weeks for 20 weeks, and the pancreas was examined. In addition, 6 four-week-old male Wistar-Bonn/Kobori rats were sacrificed and studied as starting reference. Finally, Wistar rats (n=36) were studied as controls. MAIN OUTCOME MEASURE: TP53INP1 mRNA expression was determined by reverse transcription-polymerase chain reaction using semi-quantitative analysis, direct sequencing and in situ hybridization. RESULTS: TP53INP1 mRNA was strongly expressed at 12 weeks when chronic pancreatitis developed, with a second peak at 20 weeks. The expression kinetics of TP53INP1 mRNA paralleled acinar cell apoptosis assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. The p53 mRNA expression showed a single peak at 12 weeks. In situ hybridization revealed that TP53INP1 mRNA was expressed mainly in acinar cells. Therapeutic drugs such as camostat mesilate and a herbal medicine Saiko-keishi-to suppressed the TP53INP1 mRNA expression. TP53INP1 mRNA induction in acinar cells was confirmed with in vitro experiments using an arginine-induced rat pancreatic acinar AR4-2J cell injury model. CONCLUSIONS: TP53INP1 expression may reflect the acute-phase response and apoptosis of acinar cells in the course of chronic pancreatitis.