Increased expression of Smad6 deteriorates murine acute experimental pancreatitis in two models.

BACKGROUND: Smad6 is implicated in the inhibition of bone morphogenetic protein signalling. However, the function of Smad6 in the pancreas remains obscure. METHODS: To elucidate the unknown function of Smad6, we developed transgenic mice selectively expressing Smad6 in pancreatic acinar cells using a plasmid construct coding rat elastase 1 enhancer/promoter. RESULTS: Smad6 transgenic mice had no specific distinguishing phenotype such as body weight, pancreatic wet weight and concentrations of pancreatic protein. However, Smad6 transgenic mice reacted to hyperstimulation by caerulein injection or a diet containing 0.5% ethionine. Maximal amylase release stimulated by CCK-8 was significantly decreased in Smad6 transgenic mice acini, and trypsin activities in transgenic mice acini were significantly increased after stimulation of CCK-8. There was no difference in effect of CCK-8 stimulation on the subsequent increase in intracellular free Ca2+ concentration ([Ca2+](i)) between wild-type and transgenic mice acini. These findings suggest that reduced pancreatic enzyme secretion was caused by the disorder of its downstream signal transduction pathways in acinar cells. The amino acid sequence at the N-terminus of Smad6 was similar to that of synaptosome-associated protein (SNAP) 25 interacting protein, which plays an important role in regulating exocytosis of pancreatic enzymes in acinar cells. Pancreatic SNAP25 protein levels in transgenic mice were decreased after caerulein-induced pancreatitis. CONCLUSIONS: These results suggest that elevated expression of Smad6 inhibits normal function of SNAP25-interacting protein and SNAP25, reduces amylase secretion in acinar cells, and increases the susceptibility of acinar cells to the onset of pancreatitis.

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. MATERIALS AND METHODS: The PSCs were isolated from the pancreas of male Wister rats with Nycodenz gradient methods and cells between passages one and four were used. Isolated PSCs were cultured with ethanol (50 mM) in the absence or presence of EGCG (5 microM or 25 microM). RESULTS: The EGCG pre-treatment abolished ethanol-induced lipid peroxidation of the cell membrane, loss of total superoxide dismutase (SOD) activity and suppressed ethanol-induced gene expressions of Mn- and Cu/Zn-SOD. EGCG also suppressed ethanol-induced p38 mitogen-activated protein (MAP) kinase phosphorylation, alpha-smooth muscle actin production in PSCs and activated transforming growth factor-beta1 secretion into the medium. Furthermore, EGCG inhibited ethanol-induced type-I procollagen production and collagen secretion. In addition, EGCG inhibited transformation of freshly isolated cells to activated myofibroblast-like phenotype. CONCLUSIONS: Our results suggest that green tea and polyphenols could prevent pancreatic fibrosis by inhibiting PSC activation through the antioxidative effect.

[The long-term follow-up study of Japanese patients with ulcerative colitis].

To elucidate the long-term outcome of the ulcerative colitis we analyzed 124 patients suffering for more than 10 years concerning the long-term prognosis, cumulative rate of colectomy, cumulative risk of cancer development and cumulative survival rate. Long-term prognosis were divided to three categories as good, fair and poor, according to present disease activities, social availability and subjective judgement. One hundred and twenty four patients were divided to 66 patients with good prognosis, 27 fair and 31 poor (2:1:1). The rate of patients having active disease at each year were followed-up annually for 10 years according to final three categories of the prognosis. The serial curve of annual rate of having active disease of the patients with poor prognosis was the highest, fair prognosis the second, good prognosis the lowest. The factors affecting the final prognosis were the period before initiation of proper treatment, the severity of the first attack or the elder age (> 40 year old) at the first attack. Twenty six patients were undergone colectomy in relation to ulcerative colitis. The cumulative colectomy rate was 16.5% at 10 years and 38.5% at 15 years after the onset. Malignant disease or severe dysplasia of the colon developed in 4 patients 10 to 14 years after the onset. Cumulative survival rate was equal to the expected survival curve during 16 years. The main causes of death were intracranial hemorrhage and colorectal malignant disease.

Minute lesions of the rectum and sigmoid colon in patients with Crohn's disease.

Sigmoidoscopy with a spray of 0.1% indigocarmine was performed on 20 patients with Crohn's disease whose main lesions were located proximal to the transverse colon and on 10 age-matched healthy volunteers. Minute lesions such as apthoid lesions, areas of erythema, and small ulcers were found in 90% of patients with Crohn's disease and in 0% of healthy volunteers (p less than 0.001). Among the minute lesions, aphthoid lesions were found in the highest incidence (85%). It was difficult to determine the presence of aphthoid lesions without the spray of indigocarmine, which facilitated detection. Histologically, granulomas were found in 15% of patients with Crohn's disease. Aphthoid lesions were not associated with superficial erosions and lymphoid follicles. The presence of aphthoid lesions in the rectum and sigmoid colon would be a strong indication of the presence of Crohn's disease.

Formation of 5-hydroxykynurenine and 5-hydroxykynurenamine from 5-hydroxytryptophan in rabbit small intestine.

In order to clarify the role of indoleamine 2,3-dioxygenase [indole:oxygen 2,3-oxidoreductase (decyclizing), EC 1.13.11.17] in the metabolism of serotonin, DL-5-hydroxy[methylene-(14)C]tryptophan, a precursor of serotonin, was incubated with slices of rabbit ileum. Resulting metabolites were separated by DEAE-cellulose column and polyamide column chromatography and identified by various chromatographic techniques and enzymatic analysis. Metabolites obtained in significant amounts were serotonin, 5-hydroxyindoleacetic acid, 5-hydroxytryptophol, 5-hydroxykynurenine, 5-hydroxykynurenamine, and 4,6-dihydroxyquinoline, representing 13.2, 15.8, 7.0, 21.9, 1.3, and 2.6% of the total metabolites, respectively. The first three compounds were previously reported to be major metabolites produced from 5-hydroxytryptophan by the action of aromatic L-amino acid decarboxylase and monoamine oxidase, whereas the last three are formed by the cleavage of the indole ring by the action of indoleamine 2,3-dioxygenase. In the presence of pargyline, a monoamine oxidase inhibitor, the major metabolites obtained were serotonin, 5-hydroxykynurenine, and 5-hydroxykynurenamine, representing 29.6, 26.6, and 5.4% of the total metabolites, respectively. In the presence of RO4-4602, an aromatic amino acid decarboxylase inhibitor, 5-hydroxykynurenine was the sole major product. These results strongly suggest that the newly discovered metabolic pathway involving the cleavage of the indole ring of 5-hydroxytryptophan operates in vivo to a significant extent and that indoleamine 2,3-dioxygenase plays an important role in the regulation of serotonin levels in the small intestine of the rabbit.