Conservative treatment of chronic pancreatitis

Chronic pancreatitis has been difficult to treat because the origin, pathophysiologic mechanisms and causes of unrelenting pain are so poorly understood. Furthermore, the pharmacologic agents often employed in other diseases with pain appear to be ineffective in many cases. The conservative management of chronic pancreatitis aims at (1) limiting progression and complications of the disease; (2) replacing lost exocrine and endocrine function; and (3) pain control. Thus, life style changes such as cessation of alcohol consumption and tobacco smoking, trials of pancreatic enzymes, treatment of duct obstruction and pseudocysts, and surgical therapies are currently employed. The good news is that the understanding of the underlying pathophysiological mechanisms is now advancing rapidly, and hopefully patient-specific and highly effective therapies will become available in the near future.

Apoptosis in activated rat pancreatic stellate cells

Proliferation and matrix synthesis by activated pancreatic stellate cells (PSC) participate in the development of chronic pancreatitis. Apoptosis of PSC may terminate this process but has not yet been studied in this particular cell type and was the aim of the present study. PSC were isolated from rat pancreas and characterized for expression of glial fibrillary acidic protein, alpha-smooth muscle actin, CD95, and tumor necrosis factor-alpha-related apoptosis-inducing ligand (TRAIL) receptors. Apoptosis was determined by TdT-UTP nick end-labeling reaction, annexin V binding, and caspase-8 activation. Both CD95L and TRAIL induced apoptosis in PSC. The apoptotic response was minor in PSC cultured for 7 days but increased markedly thereafter. Sensitization of PSC with culture duration was accompanied by increased expression of CD95 and TRAIL receptor 2 and no alterations of Flip expression or protein kinase B phosphorylation but was paralleled by the appearance of a COOH-terminal cleavage product of receptor-interacting protein. PSC apoptosis was also induced by PK-11195, a ligand of the peripheral benzodiazepine receptor. PSC apoptosis may be important in terminating the wound-healing response after pancreas injury and exhibits features distinct from apoptosis induction in hepatic stellate cells.

Growth factors in pancreatic health and disease

In this article the role of different growth factors and their receptors in the pathogenesis of chronic pancreatitis and pancreatic cancer is discussed. The expression of members of the epidermal growth factor family, the fibroblast growth factor family, the transforming growth factor-beta family, the platelet-derived growth factor family, the nerve growth factor family, the insulin-like growth factor family and their signaling receptors is presented, and a correlation of the molecular data with clinical and pathological changes is performed. A number of these growth factors and their receptors are markedly overexpressed in chronic pancreatitis and pancreatic cancer. In chronic pancreatitis, overexpression of growth factors and their receptors contributes to tissue remodeling and fibrogenesis. In contrast to chronic pancreatitis, pancreatic cancer is associated with a variety of genetic alterations, including mutations in tumor suppressor genes and cell cycle regulators. In the presence of these genetic disturbances, enhanced expression of growth factors and their receptors contributes to cell proliferation and enhances the aggressiveness of pancreatic cancer cells. In summary, growth factors and their receptors are often altered in chronic pancreatitis and pancreatic cancer and contribute to various pathogenetic aspects in these disorders.

Mesenchymal cells in the liver--one cell type or two?

The wall of the liver sinusoid is made of highly specialized cells, the hepatic stellate cells (HSC) which together with the sinusoidal endothelial cells represent a loose barrier to the corpusculate part of the blood flowing through the liver. Quiescent stellate cells (quiescent HSC) store Vitamin A; "activated" stellate cells become involved in the reaction to acute or chronic noxae damaging the liver parenchyma. Activated HSC show increased protein synthesis capacity, increased DNA-synthesis and acquire a myofibroblast-like phenotype. Under similar conditions liver myofibroblasts (MF) of the portal field and of the pericentral area may also become "activated" by increasing protein synthesis, DNA synthesis and cell division. They express the fibulin-2 gene and produce large amounts of IL-6. In contrast to "activated" HSC they do not undergo spontaneous apoptosis in vitro and do not express the CD95-ligand gene. So far no definite prove has been found for a "transdifferentiation" of HSC to myofibroblasts. On the contrary an increasing amount of data support the conviction that HSC and MF represent two similar but not identical cell populations the latter being comparable to those of other organs.

Lipopolysaccharides in liver injury: molecular mechanisms of Kupffer cell activation

Endogenous gut-derived bacterial lipopolysaccharides have been implicated as important cofactors in the pathogenesis of liver injury. However, the molecular mechanisms by which lipopolysaccharides exert their effect are not entirely clear. Recent studies have pointed to proinflammatory cytokines such as tumor necrosis factor-alpha as mediators of hepatocyte injury. Within the liver, Kupffer cells are major sources of proinflammatory cytokines that are produced in response to lipopolysaccharides. This review will focus on three important molecular components of the pathway by which lipopolysaccharides activate Kupffer cells: CD14, Toll-like receptor 4, and lipopolysaccharide binding protein. Within the liver, lipopolysaccharides bind to lipopolysaccharide binding protein, which then facilitates its transfer to membrane CD14 on the surface of Kupffer cells. Signaling of lipopolysaccharide through CD14 is mediated by the downstream receptor Toll-like receptor 4 and results in activation of Kupffer cells. The role played by these molecules in liver injury will be examined.

Activated rat pancreatic stellate cells express intercellular adhesion molecule-1 (ICAM-1) in vitro

INTRODUCTION

Activated pancreatic stellate cells (PSCs) have recently been implicated in the pathogenesis of pancreatic fibrosis.

AIMS

To examine the role of PSCs in pancreatic inflammation by determining whether activated PSCs express intercellular adhesion molecule-1 (ICAM-1).

METHODOLOGY

Culture-activated rat PSCs were treated with interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), ethanol, or acetaldehyde. ICAM-1 expression was analyzed by flow cytometry. The induction of mRNA was assessed by Northern blot analysis. The binding activity of transcription factors was examined by electrophoretic mobility shift assay. The activation of mitogen-activated protein kinases was assessed by Western blotting with use of antiphosphospecific antibodies. The adhesion of MOLT-4 cells to activated PSCs was also assessed.

RESULTS

Culture-activated PSCs expressed ICAM-1. The expression was increased in response to IL-1 beta and TNF-alpha but not to alcohol, with comparable mRNA induction. IL-1 beta and TNF-alpha increased the nuclear factor-kappa B (NF-kappa B)-specific and activator protein-1-specific DNA binding activity, whereas the NF-IL6 activity was not altered. Alcohol did not increase NF-kappa B binding activity. IL-1 beta and TNF-alpha activated extracellular signal-regulated kinase 1/2, c-Jun N-terminal kinase/stress-activated protein kinase, and p38 mitogen-activated protein kinase. Inducible ICAM-1 expression was blocked by pyrrolidine dithiocarbamate, a specific inhibitor of NF-kappa B activation, but not by inhibitors of mitogen-activated protein kinase pathways. IL-1 beta and TNF-alpha increased the ICAM-1-mediated binding of MOLT-4 cells to activated PSCs, indicating a role of ICAM-1 in the adhesion of leukocytes to PSCs.

CONCLUSION

Our results suggest that activated PSCs express ICAM-1 mainly through the activation of NF-kappa B, thus playing a role in the pathogenesis of pancreatic inflammation.

Alcohol activates activator protein-1 and mitogen-activated protein kinases in rat pancreatic stellate cells

Alcohol is a major cause of both acute and chronic pancreatitis. Activated pancreatic stellate cells (PSCs) have recently been implicated in the pathogenesis of pancreatic inflammation and fibrosis. Herein, we examined the effect of ethanol and acetaldehyde on the activation of transcription factors and mitogen-activated protein (MAP) kinases in PSCs. PSCs were isolated from rat pancreas tissue and used in their culture-activated, myofibroblast-like phenotype. PSCs were treated with ethanol and acetaldehyde at clinically relevant concentrations (50 mM and 200 microM, respectively). Ethanol and acetaldehyde activated activator protein-1 but not nuclear factor-kappaB. In addition, they activated three classes of MAP kinases: extracellular signal-regulated kinase 1/2, c-Jun N-terminal kinase/stress-activated protein kinase, and p38 MAP kinase. Ethanol- and acetaldehyde-induced activation of activator protein-1 and MAP kinases was blocked by the antioxidant N-acetyl-cysteine, suggesting a role of oxidative stress in the signal transduction. Ethanol and acetaldehyde induced alpha1(I) procollagen gene expression but did not induce intercellular adhesion molecule-1 and monocyte chemoattractant protein-1. The acetaldehyde-induced increase of alpha1(I) procollagen gene expression was inhibited by the p38 MAP kinase inhibitor 4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)imidazole (SB203580) but not by the MAP kinase inhibitor 2'-amino-3'-methoxyflavone (PD98059). Specific activation of these signal transduction pathways may play a role in the pathogenesis of alcohol-induced pancreatic injury.

Evaluation of factors that have reduced mortality from acute pancreatitis over the past 20 years

BACKGROUND

The mortality associated with acute pancreatitis varies markedly in different studies, with most frequently reported mortality rates of 10% to 15% for all cases and 15% to 90% for attacks regarded as "severe." More recently, various centers have recorded lower mortality rates of 4% to 7% for all attacks of acute pancreatitis and 20% to 50% for those regarded as severe.

GOALS

To investigate whether there has been a reduction in mortality associated with acute pancreatitis over the past 20 years and the reasons for this reduction.

STUDY

Intended as a review, this study included the authors' 20-year prospective assessment of mortality as it relates to the severity of the disease, complications, and current therapy. For the mortality results, the study was divided into four 4-year periods from 1977 to 1998 and the past 3 years (i.e., 1998-2001). For comparison, the mortality figures from some other large studies are presented.

RESULTS

This study showed that the initial reduction in mortality related to acute pancreatitis coincided with the recognition and application of the signs of severity, either Ranson's prognostic signs or Bank's clinical criteria. These signs dictated admission to intensive care unit (ICU) therapy, the intensity of ICU monitoring, and the importance of organ-specific emergent therapy. Further mortality reduction in the 1990s could be attributed to either a more select study sample or earlier and more selective endoscopic or surgical debridement of infected tissue, endoscopic cyst drainage, and angiographic control of gastrointestinal bleeding. Improved nutritional support by jejunal feeding, earlier use of antibiotic therapy, gut sterilization, early endoscopic retrograde cholangiopancreatography for common bile duct stones and necrosectomy for noninfected necrosis have reduced the overall mortality associated with acute pancreatitis to a mean of 5% (range, 3.8-7%) for all cases and 20% (range, 15-25%) for severe cases. However, it is clear that the greater the number of signs denoting severity of organ failure, the higher the mortality.

CONCLUSIONS

There has been considerable reduction in the mortality associated with acute pancreatitis over the past 20 years. The reasons are multifactorial, but recognition of severity signs, early implementation of organ-specific therapy, and newer endoscopic, surgical, and angiographic therapy for infection cyst and bleeding appear to have been the major factors in reducing mortality.

Pancreatic cholesterol esterase, ES-10, and fatty acid ethyl ester synthase III gene expression are increased in the pancreas and liver but not in the brain or heart with long-term ethanol feeding in rats

INTRODUCTION

Chronic alcohol consumption predisposes susceptible individuals to both acute and chronic pancreatitis.

AIMS

Our hypothesis was that alcohol increases the risk of pancreatitis by disrupting defense mechanisms and/or enhancing injury-associated pathways through altered gene expression. Hence, we studied the expression of pancreatic genes in rats chronically exposed to ethanol.

METHODOLOGY

Male Wistar rats were pair-fed liquid diets without and with ethanol for 4 weeks. Total RNA was extracted from rat pancreas and other organs. The mRNA expression patterns among pancreatic samples from ethanol-fed rats and controls were compared with use of mRNA differential display. The differentially expressed cDNA tags were isolated, cloned, and sequenced.

RESULTS

One cDNA tag that was overexpressed in the pancreas showed 99% sequence homology to a rat pancreatic cholesterol esterase mRNA (CEL; Enzyme Commission number [EC] 3.1.1.13). The differential expression was confirmed by realtime PCR. Gene expression was also increased in the liver but not in the heart or brain of the alcohol-fed rats. Because CEL has fatty acid ethyl ester (FAEE)-generating activity and FAEEs play a major role in acute alcoholic pancreatitis, we determined the expression of other genes encoding for FAEE-generating enzymes and showed similar organ-specific expression patterns.

CONCLUSION

Our results demonstrate that chronic ethanol consumption induced expression of FAEE-related genes in the pancreas and liver. This upregulation may be a central mechanism leading to acinar cell injury.

S-Adenosylmethionine, cytokines, and alcoholic liver disease

Hepatic deficiency of S-adenosylmethionine (AdoMet) is a critical acquired metabolic abnormality in alcoholic liver disease (ALD) and in many experimental models of hepatotoxicity. Subnormal AdoMet, elevated serum tumor necrosis factor (TNF), and endotoxemia (LPS) are hallmarks of ALD and experimental liver injury. AdoMet deficiency is attributed to its subnormal synthesis, but mechanisms for increased TNF are not known. AdoMet deficiency may affect the critical balance of proinflammatory (e.g., TNF) and antiinflammatory [e.g., interleukin (IL)-10] cytokines. Rats maintained on a choline-deficient diet with limited amounts of methionine (MCD diet) developed AdoMet deficiency. When challenged with LPS, rats fed MCD diet had significantly increased serum TNF levels and worse liver injury compared with findings for controls. Exogenous AdoMet attenuated liver injury and serum TNF levels. Results of in vitro studies with the use of RAW 264.7 cells demonstrated that exogenous AdoMet supplementation lowered LPS-induced TNF formation in a dose-dependent manner, and AdoMet deficiency enhanced TNF secretion and TNF gene expression. AdoMet also dose-dependently decreased LPS-stimulated TNF production from monocytes obtained from patients with alcoholic hepatitis. Finally, AdoMet supplementation stimulated production of the antiinflammatory cytokine IL-10. Interleukin-10 plays a critical role in the modulation of TNF production, and IL-10 may inhibit hepatic fibrosis. This article will review (1) the role of AdoMet in ALD/liver injury, (2) the role of TNF/proinflammatory cytokines in ALD, (3) potential roles of AdoMet in TNF/proinflammatory cytokine regulation in ALD, and (4) conclusions and future directions.

Endogenous interleukin-10 modulates fibrosis and regeneration in experimental chronic pancreatitis

Interleukin (IL)-10, a potent anti-inflammatory cytokine, limits the severity of acute pancreatitis and downregulates transforming growth factor (TGF)-beta release by inflammatory cells on stimulation. Proinflammatory mediators, reactive oxygen species, and TGF-beta can activate pancreatic stellate cells and their synthesis of collagen I and III. This study evaluates the role of endogenous IL-10 in the modulation of the regeneration phase following acute pancreatitis and in the development of pancreatic fibrosis. IL-10 knockout (KO) mice and their C57BL/6 controls were submitted to repeated courses (3/wk, during 6 wk, followed by 1 wk of recovery) of cerulein-induced acute pancreatitis. TGF-beta(1) release was measured on plasma, and its pancreatic expression was assessed by quantitative RT-PCR and immunohistochemistry. Intrapancreatic IL-10 gene expression was assessed by semiquantitative RT-PCR, and intrapancreatic collagen content was assessed by picrosirius staining. Activated stellate cells were detected by immunohistochemistry. S phase intrapancreatic cells were marked using tritiated thymidine labeling. After repeated acute pancreatitis, IL-10 KO mice had more severe histological lesions and fibrosis (intrapancreatic collagen content) than controls. TGF-beta(1) plasma levels, intrapancreatic transcription, and expression by ductal and interstitial cells, as well as the number of activated stellate cells, were significantly higher. IL-10 KO mice disclosed significantly fewer acinar cells in S phase, whereas the opposite was observed for pseudotubular cells. Endogenous IL-10 controls the regeneration phase and limits the severity of fibrosis and glandular atrophy induced by repeated episodes of acute pancreatitis in mice.

Hereditary pancreatitis: a model for inflammatory diseases of the pancreas

Acute and chronic pancreatitis remain among the most recalcitrant of all diseases to investigation and intervention. In the majority of patients, excessive alcohol consumption is associated with development of the disease. Therefore, several theories have been proposed seeking to explain the relationship between alcohol and the development of acute and chronic pancreatitis. However, recent investigations in hereditary pancreatitis provided important insights into chronic pancreatitis pathogenesis and offer an important model for understanding pancreatic inflammation. This article highlights several advances gained from investigating hereditary pancreatitis kindreds, and reviews the TIGAR-O risk/aetiology classification system. Finally, the major independent theories on development of chronic pancreatitis are reviewed with respect to the SAPE hypothesis of chronic pancreatitis pathogenesis.

Cystic fibrosis and related diseases of the pancreas

The discovery of the gene for cystic fibrosis (CF), the cystic fibrosis transmembrane conductance regulator (CFTR), brought about a new era in the study of this disease. Identification of the molecular target has yielded a flood of data that add to our understanding of the pathogenesis, diagnosis and treatment of CF. The CFTR protein is a cAMP-regulated Cl(-) channel with multiple functions in epithelial cells. In the exocrine pancreas the CFTR plays a key role in the apical Cl(-), HCO(3)(-), and water transport in duct cells. The severe loss of functions, caused by mutations of the CFTR gene, leads to pathological lesions of the pancreas. Over 1200 CFTR mutations and polymorphisms have been identified and their diversity may explain the high level of heterogeneity in the CF phenotype. Mutation analyses of the CFTR gene have revealed a spectrum of CFTR-related diseases that do not fit the classical CF picture but are associated with dysfunction of CFTR, such as chronic pancreatitis.

Pancreatic stellate cell activation and MMP production in experimental pancreatic fibrosis

BACKGROUND

The early events in pancreatic fibrosis are poorly understood. We examined the production of collagen and matrix metalloproteinases as well as the activation of pancreatic stellate cells in a rodent model of pancreatic fibrosis.

MATERIALS AND METHODS

Pancreatitis was induced in rats by hyperstimulation with cerulein (50 microg/kg/day ip) and concurrent pancreatic duct obstruction (SHOP model) for 96 h (n = 48). Sham animals were injected with saline and underwent laparotomy and manipulation of the pancreas with no duct obstruction (n = 28). Rats were sacrificed daily for 18 days. Serial pancreatic sections were stained with H&E [histology], trichrome [collagen], and alpha smooth muscle actin (alpha-SMA) antibodies [activated stellate cells]. Total pancreatic matrix metalloproteinase (MMP)-2 and 9 were determined by gelatin zymography. MMP-1 production was examined using Western blotting.

RESULTS

There were occasional alpha-SMA-positive cells in the pancreatic parenchyma of normal and sham animals. Within 48 h of pancreatitis induction in SHOP animals, histologic evidence of pancreatic inflammation was present, and stellate cells (alpha-SMA-positive cells) appeared surrounding pancreatic acini. The appearance of these cells was followed by collagen deposition in the same area. MMP-1 and 2 proteins increased significantly during pancreatitis while MMP-9 did not. The pancreatic architecture returned to normal by 18 days after the induction of pancreatitis.

CONCLUSION

Acute pancreatic inflammation results in stellate cell activation and collagen deposition in the same area. Collagen is then resorbed at a time when MMP-1 and 2 peak. The fibrosis of acute pancreatic inflammation in this model completely resolves with restoration of normal architecture.

Expression of transforming growth factor-beta 1 by pancreatic stellate cells and its implications for matrix secretion and turnover in chronic pancreatitis

Pancreatic stellate cells mediate fibrosis in chronic pancreatitis. Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs)-1 and -2 are crucial modulators of fibrosis. Transforming growth factor-beta (TGF-beta) is a key regulator of extracellular matrix production and myofibroblast proliferation. We have examined MMP and TIMP synthesis by transformed cultured pancreatic stellate cells and their regulation by TGF-beta 1. By Northern analysis they expressed mRNAs for procollagen 1, TIMP-1, TIMP-2, and MMP-2. Expression of membrane type-1 MMP was confirmed by Western blotting. By immunohistochemistry these enzymes localized to fibrotic areas in human chronic pancreatitis. Active TGF-beta 1 constitutes 2 to 5% of total TGF-beta 1 secreted by pancreatic stellate cells; they express TGF-beta receptors I and II. Exogenous TGF-beta 1 (10 ng/ml) significantly increased procollagen-1 mRNA by 69% and collagen protein synthesis by 34%. Similarly TGF-beta 1 at 0.1, 1, and 10 ng/ml significantly reduced cellular proliferation rate by 37%, 44%, and 44%, respectively, whereas pan-TGF-beta-neutralizing antibody increased proliferation by 40%. TGF-beta1 (10 ng/ml) down-regulated MMP-9 by 54% and MMP-3 by 34% whereas TGF-beta 1-neutralizing antibody increased MMP-9 expression by 39%. Pancreatic stellate cells express both mediators of matrix remodeling and the regulatory cytokine TGF-beta 1 that, by autocrine inhibition of MMP-3 and MMP-9, may enhance fibrogenesis by reducing collagen degradation.

Ethanol, oxidative stress, and cytokine-induced liver cell injury

Both clinical findings and results of experiments with animal models of alcoholic hepatitis have shown the importance of cytokine-mediated cell-cell interactions in the onset of ethanol-induced liver damage. Proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1 beta (IL-1 beta), and interleukin-6, are released from Kupffer cells or infiltrating neutrophils and macrophages and elicit defensive responses in parenchymal cells, including activation of apoptosis. Reactive oxygen species (ROS) and reactive nitrogen species (RNS), generated in response to cytokine-induced stress signals in parenchymal cells and also by activation of Kupffer cells and inflammatory cells, further mobilize cellular defense mechanisms. When these defensive responses are overwhelmed cells may die by necrosis, further stimulating inflammatory responses and infiltration of neutrophils. Chronic ethanol intake (i.e., many years of heavy alcohol use in human patients, several weeks or months in experimental animals) enhances the damaging consequences of these events through a variety of mechanisms. The formation of cytokines in the liver is stimulated by increasing circulating levels of endotoxin and by enhancing the responsiveness of Kupffer cells to such stimuli. In addition, ethanol promotes oxidative stress, both by increased formation of ROS and by depletion of oxidative defenses in the cell. Furthermore, liver cells from ethanol-treated animals are more susceptible to the cytotoxic effects of TNF-alpha and other cytokines than cells from control animals. Mitochondria play a critical role in the apoptotic response, and alterations in mitochondrial function after chronic ethanol treatment may contribute to enhanced cell death by apoptosis or necrosis. How the shift in the balance of cytokine-induced defensive and damage responses in hepatocytes contributes to the liver injury that occurs in alcoholic hepatitis remains poorly characterized and should be a rewarding area for future studies.

Neutrophil-mediated tissue injury in alcoholic hepatitis

The presence of polymorphonuclear leukocytes (neutrophils) in liver parenchyma is a prominent feature of alcoholic hepatitis. However, the pathophysiological importance of these phagocytes and potential injury mechanisms in alcoholic hepatitis remain unclear. This review summarizes the current knowledge on basic mechanisms of neutrophil-induced liver injury as it emerged from studying a number of different experimental models. This general concept of neutrophil-mediated liver cell injury agrees with many observations made by examining liver sections obtained from patients with alcoholic hepatitis. These include the presence of extravasated neutrophils in the liver, evidence for degranulation of neutrophils in the parenchyma, and excessive formation of neutrophil chemoattractants such as CXC chemokines in liver cells. Colocalization and a strong quantitative correlation between apoptotic hepatocytes and neutrophils could indicate apoptosis-induced transmigration of neutrophils during alcoholic hepatitis, similar to events previously demonstrated in experimental models. Furthermore, circulating neutrophils are primed for reactive oxygen species and inflammatory mediator formation. However, clear evidence for a neutrophil-induced injury in alcoholic hepatitis is missing. Unfortunately, most experimental models of alcoholic liver disease do not have a prominent neutrophilic infiltrate. Therefore, a high priority of future research has to be to develop an experimental model that realistically mimics the neutrophil component of alcoholic hepatitis in human beings. This would allow investigators to test the concept that neutrophils are important for cell injury during alcoholic hepatitis and to identify potential therapeutic intervention strategies.

The use of silymarin in the treatment of liver diseases

The high prevalence of liver diseases such as chronic hepatitis and cirrhosis underscores the need for efficient and cost-effective treatments. The potential benefit of silymarin (extracted from the seeds of Silybum marianum or milk thistle) in the treatment of liver diseases remains a controversial issue. Therefore, the objective of this review is to assess the clinical efficacy and safety of silymarin by application of systematic approach. 525 references were found in the databases, of which 84 papers were retained for closer examination and 36 were deemed suitable for detailed analysis. Silymarin has metabolic and cell-regulating effects at concentrations found in clinical conditions, namely carrier-mediated regulation of cell membrane permeability, inhibition of the 5-lipoxygenase pathway, scavenging of reactive oxygen species (ROS) of the R-OH type and action on DNA-expression, for example, via suppression of nuclear factor (NF)-kappaB. Pooled data from case record studies involving 452 patients with Amanita phalloides poisoning show a highly significant difference in mortality in favour of silibinin [the main isomer contained in silymarin] (mortality 9.8% vs 18.3% with standard treatment; p < 0.01). The available trials in patients with toxic (e.g. solvents) or iatrogenic (e.g. antispychotic or tacrine) liver diseases, which are mostly outdated and underpowered, do not enable any valid conclusions to be drawn on the value of silymarin. The exception is an improved clinical tolerance of tacrine. In spite of some positive results in patients with acute viral hepatitis, no formally valid conclusion can be drawn regarding the value of silymarin in the treatment of these infections. Although there were no clinical end-points in the four trials considered in patients with alcoholic liver disease, histological findings were reported as improved in two out of two trials, improvement of prothrombin time was significant (two trials pooled) and liver transaminase levels were consistently lower in the silymarin-treated groups. Therefore, silymarin may be of use as an adjuvant in the therapy of alcoholic liver disease. Analysis was performed on five trials with a total of 602 patients with liver cirrhosis. The evidence shows that, compared with placebo, silymarin produces a nonsignificant reduction of total mortality by -4.2% [odds ratio (OR) 0.75 (0.5 - 1.1)]; but that, on the other hand, the use of silymarin leads to a significant reduction in liver-related mortality of-7% [OR: 0.54 (0.3 - 0.9); p < 0.01]. An individual trial reported a reduction in the number of patients with encephalopathy of -8.7% (p = 0.06). In one study of patients with cirrhosis-related diabetes mellitus, the insulin requirement was reduced by -25% (p < 0.01). We conclude that available evidence suggests that silymarin may play a role in the therapy of (alcoholic) liver cirrhosis. Silymarin is has a good safety record and only rare case reports of gastrointestinal disturbances and allergic skin rashes have been published. This review does not aim to replace future prospective trials aiming to provide the 'final' evidence of the efficacy of silymarin.

Pancreatic stellate cells respond to inflammatory cytokines: potential role in chronic pancreatitis

BACKGROUND

It is now generally accepted that chronic pancreatic injury and fibrosis may result from repeated episodes of acute pancreatic necroinflammation (the necrosis-fibrosis sequence). Recent studies suggest that pancreatic stellate cells (PSCs), when activated, may play an important role in the development of pancreatic fibrosis. Factors that may influence PSC activation during pancreatic necroinflammation include cytokines known to be important in the pathogenesis of acute pancreatitis, such as tumour necrosis factor alpha (TNF-alpha), and the interleukins 1, 6, and 10 (IL-1, IL-6, and IL-10).

AIM

To determine the effects of these cytokines on PSC activation, as assessed by cell proliferation, alpha smooth muscle actin (alpha-SMA) expression, and collagen synthesis.

METHODS

Cultured rat PSCs were incubated with cytokines for 24 hours. Cell proliferation was assessed by measuring (3)H thymidine incorporation into cellular DNA, alpha-SMA expression by western blotting, and collagen synthesis by incorporation of (14)C proline into collagenase sensitive protein. mRNA levels for procollagen alpha(1)(1) in PSCs were determined by northern and dot blotting methods.

RESULTS

Expression of alpha-SMA by PSCs was increased on exposure to each of the cytokines used in the study. Stellate cell proliferation was stimulated by TNF-alpha but inhibited by IL-6, while IL-1 and IL-10 had no effect on PSC proliferation. Collagen synthesis by PSCs was stimulated by TNF-alpha and IL-10, inhibited in response to IL-6, and unaltered by IL-1. Changes in collagen protein synthesis in response to TNF-alpha, IL-10, and IL-6 were not regulated at the mRNA level in the cells.

CONCLUSION

This study has demonstrated that PSCs have the capacity to respond to cytokines known to be upregulated during acute pancreatitis. Persistent activation of PSCs by cytokines during acute pancreatitis may be a factor involved in the progression from acute pancreatitis to chronic pancreatic injury and fibrosis.

Diabetic hypertriglyceridemia-induced acute pancreatitis masquerading as biliary pancreatitis

Diabetes mellitus has a profound effect on plasma lipid metabolism especially triglycerides. One complication of hypertriglyceridemia is acute pancreatitis. Here, we report a case of diabetic hypertriglyceridemia-induced recurrent acute pancreatitis that masquerades as biliary pancreatitis. Institution of insulin therapy caused a resolution of the hypertriglyceridemia and a cessation of the episodes of acute pancreatitis.

Role of TGF-beta1 in the development of pancreatic fibrosis in Otsuka Long-Evans Tokushima Fatty rats

Recently established Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of naturally occurring obesity diabetes, exhibit progressive accumulation of connective tissue in the pancreas. The present study was designed to determine the pathogenic role of transforming growth factor-beta1 (TGF-beta1) in the development of pancreatic fibrosis in OLETF rats by investigating the serial changes in the expression of TGF-beta1 and extracellular matrix (ECM) in the pancreas. Progressive proliferation of connective tissue arose from the interstitial region surrounding islets at 20 wk of age and extended to the exocrine pancreas adjacent to the islets. TGF-beta1 mRNA levels in the pancreas increased at 20 wk of age and reached a peak value at 30 wk of age. Fibronectin (FN) and procollagen types I and III mRNAs peaked at 20 wk of age and remained at higher levels than those in the nondiabetic counterparts Long-Evans Tokushima Otsuka rats until 50 wk of age. Immunoreactivities for TGF-beta1 and FN were found in islets of OLETF rats at 20 wk of age and were seen in acinar and interstitial cells at 50 wk of age. Moreover, alpha-smooth muscle actin was located at interstitial region surrounding the islets. Proliferation of the connective tissue in the pancreas of OLETF rats closely correlated with expression of TGF-beta1 and ECM. Our results suggest that the development of pancreatic fibrosis in OLETF rats extends from endocrine to exocrine pancreas and that TGF-beta1 is involved in pancreatic fibrosis of OLETF rats.

Current insights into the pathogenesis of acute and chronic pancreatitis

For a long time the pathogenesis of pancreatitis has remained enigmatic. Recent developments in cellular and molecular biology, however, have provided a tremendous research impetus and some of its mysteries are finally being disclosed. This review discusses the implications of the discovery of the disease gene in hereditary pancreatitis and outlines recent advances in our understanding of the mechanism and site of trypsinogen activation and the role of immunocytes and cytokines in acute pancreatitis. With respect to chronic pancreatitis, this review focuses on its association with mutations in the cystic fibrosis conductance regulator gene and the mechanisms of pancreatic fibrosis. These advances in our knowledge of the pathogenesis of the disease, together with emerging biotechnological techniques, will boost the development of future therapies aimed at strategically targeting key pathophysiological processes involved in acute and chronic pancreatitis.

Polymorphism in alcohol-metabolizing enzymes, glutathione S-transferases and apolipoprotein E and susceptibility to alcohol-induced cirrhosis and chronic pancreatitis

BACKGROUND AND AIM

Susceptibility to organ damage induced by alcohol may be due to inherited variation (polymorphism) in ethanol-metabolizing enzymes, or to polymorphisms affecting free radical or lipid metabolism mediated by enzymes such as glutathione S-transferases and apolipoprotein E. The aim was to compare the genotype frequencies of alcohol dehydrogenase-2 (ADH2), ADH3, aldehyde dehydrogenase-2 (ALDH2), cytochrome P450-2E1 (CYP2E1), glutathione S-transferase-M1 (GSTM1), GSTT1, and apolipoprotein E in patients with alcoholic cirrhosis and alcoholic chronic pancreatitis to those in control groups.

PATIENTS AND METHODS

The case-control study was restricted to Caucasian adults: 57 with alcoholic cirrhosis, 71 with alcoholic chronic pancreatitis, 57 alcoholics without apparent organ damage and 200 healthy blood donors. Genotypes were determined by restriction fragment length polymorphism after amplification of genomic DNA by polymerase chain reaction.

RESULTS

The genotype ADH3*2/*2 was more frequent in patients with cirrhosis (40%) than blood donors (12%; OR 4.92, 95% CI 2.36-10.31) and patients with chronic pancreatitis (8%; OR 7.33, 95% CI 2.54-23.78) but was not significantly different from alcoholic controls (23%; OR 2.27, 95% CI 0.95-5.66). Patients with cirrhosis also had a higher frequency (P < 0.05) of ADH2*1/*1 (100%) than blood donors (92%) and those with chronic pancreatitis (93%). The frequencies of genotypes of ALDH2, CYP2E1, GSTM1, GSTT1 and apolipoprotein E were similar in all groups.

CONCLUSION

Alcoholic cirrhosis but not alcoholic chronic pancreatitis is associated with ADH3*2/*2 and perhaps with ADH2*1/*1. Both genes encode less active alcohol-metabolizing enzymes that may be associated with cirrhosis because of delayed formation of acetaldehyde (with higher intakes of alcohol), or diversion of alcohol metabolism through pathways other than ADH.

Myofibroblasts are responsible for the desmoplastic reaction surrounding human pancreatic carcinomas

BACKGROUND

The cell type responsible for the desmoplastic reaction surrounding human pancreatic carcinoma is unknown. Hepatic stellate cells, which activate to a myofibroblast-like form, are responsible for collagen deposition in cirrhosis and around hepatocellular carcinomas. Recently, pancreatic stellate cells have been described and implicated in the fibrosis of chronic pancreatitis. We sought to determine whether these cells are responsible for the scirrhous reaction surrounding pancreatic adenocarcinomas.

METHODS

Archival formalin-fixed, paraffin-embedded pancreatic tissues from 10 patients undergoing pancreaticoduodenectomy for ductal adenocarcinoma and from 2 patients with pancreatic islet cell tumors were examined immunohistochemically for alpha-smooth muscle actin (alpha-SMA), smooth muscle myosin heavy chain (SMMHC), procollagen I, collagen IV, and endothelial cell markers, von Willebrand factor and cluster of differentiation 31.

RESULTS

In non-neoplastic areas, staining for alpha-SMA and SMMHC was confined to interlobular septal regions. In contrast, the desmoplastic reaction surrounding all 10 pancreatic adenocarcinoma specimens displayed intense interstitial staining for alpha-SMA, SMMHC, and collagen IV but no staining for von Willebrand factor and cluster of differentiation 31. Procollagen I staining localized intracellularly to fibroblast-shaped cells within this alpha-SMA/SMMHC-positive scirrhous region. Islet cell tumors demonstrated an increase in alpha-SMA staining, although this was not as marked as in ductal adenocarcinomas.

CONCLUSIONS

A massive increase in myofibroblast activity, compatible with the activation of stellate cells, is associated with the deposition of collagen types I and IV in the desmoplastic reaction around pancreatic adenocarcinomas.

Cytogenetic study of chronic ethanol consumption in rats

Ethanol was supplied in the drinking water of Wistar rats at a concentration of 20% v/v for up to 30 days. The animals treated with ethanol demonstrated a nonsignificant increase in chromosomal aberration frequency when compared with control animals. The mitotic index values obtained indicated no significant differences between ethanol treatment and control groups. The final weights of control rats were significantly greater than those of the ethanol-treated group. Chronic administration of ethanol showed no clastogenic or cytotoxic effect. After chronic ethanol consumption, the cytochromes P450 activity increases, thus possibly preventing the ethanol that has entered the circulation from reaching excessive levels, leading to metabolic adaptation and/or tolerance.

Ligands of peroxisome proliferator-activated receptor-gamma block activation of pancreatic stellate cells

Activated pancreatic stellate cells (PSCs) have recently been implicated in the pathogenesis of pancreatic fibrosis and inflammation. Peroxisome proliferator-activated receptor gamma (PPAR-gamma) is a ligand-activated transcription factor which controls growth, differentiation, and inflammation in different tissues. Roles of PPAR-gamma activation in PSCs are poorly characterized. Here we examined the effects of PPAR-gamma ligands on the key parameters of PSC activation. PSCs were isolated from rat pancreas tissue, and used in their culture-activated, myofibroblast-like phenotype. Activation of PPAR-gamma was induced with 15-deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2) or with troglitazone. Expression of PPAR-gamma was predominantly localized in the nuclei, and PPAR-gamma was transcriptionally active after ligand stimulation. PPAR-gamma ligands inhibited platelet-derived growth factor-induced proliferation. This effect was associated with inhibition of cell cycle progression beyond the G1 phase. PPAR-gamma ligands decreased alpha-smooth muscle actin protein expression and alpha1(I) procollagen and prolyl 4-hydroxylase(alpha) mRNA levels. Activation of PPAR-gamma also resulted in the inhibition of inducible monocyte chemoattractant protein-1 expression. 15d-PGJ2, but not troglitazone, inhibited the degradation of IkappaB-alpha and consequent NF-kappaB activation. In conclusion, activation of PPAR-gamma inhibited profibrogenic and proinflammatory actions in activated PSCs, suggesting a potential application of PPAR-gamma ligands in the treatment of pancreatic fibrosis and inflammation.

Pharmacokinetics of ethanol: a review of the methodology

This paper reviews current concepts on tools for studying the pharmacokinetics of alcohol. It has been known that ethanol metabolism occurs mainly in the liver via alcohol dehydrogenase and an accessory microsomal pathway. The contribution of each pathway has been examined by administration of metabolic inhibitors. The role of gastric alcohol dehydrogenase in the first-pass effects of ethanol has been speculative and may be relatively low. Some pharmacokinetic approaches with mathematical models have elucidated the role of gastric alcohol dehydorgenase, hepatic alcohol dehydrogenase and cytochrome P450 2E1 in ethanol elimination. The scale-up of ethanol elimination kinetics has enabled extrapolation from animal models to human kinetics. The clarification of the pharmacokinetics of ethanol is very important for estimating the effects of ethanol on biological events.

Ethanol metabolism and transcription factor activation in pancreatic acinar cells in rats

BACKGROUND & AIMS

Ethanol metabolism by pancreatic acinar cells and the role of its metabolites in ethanol toxicity to the pancreas remain largely unknown. Here, we characterize ethanol metabolism in pancreatic acinar cells and determine the effects of ethanol metabolites on nuclear factor kappa B (NF-kappa B) and activator protein (AP)-1, transcription factors that are activated in pancreatitis and mediate expression of inflammatory molecules critical for this disease.

METHODS

We measured activities of fatty acid ethyl ester (FAEE) synthase and alcohol dehydrogenase (ADH), as well as accumulation of ethanol metabolites. We measured the effects of ethanol and its metabolites on NF-kappa B and AP-1 activation by using a gel shift assay.

RESULTS

Pancreas metabolizes ethanol via both oxidative and nonoxidative pathways. Acinar cells are the main source of ethanol metabolism in the pancreas. Compared with the liver, FAEE synthase activity in the pancreas is greater, whereas that of ADH is much less. FAEEs activated NF-kappa B and AP-1, whereas acetaldehyde inhibited NF-kappa B activation. Ethanol decreased NF-kappa B binding activity in acinar cells, which was potentiated by cyanamide.

CONCLUSION

Oxidative and nonoxidative ethanol metabolites regulate transcription factors differently in pancreatic acinar cells. Ethanol may regulate NF-kappa B and AP-1 positively or negatively, depending on which metabolic pathway's effect predominates. These regulatory mechanisms may play a role in ethanol toxicity to the pancreas.

Cystic fibrosis gene mutations and pancreatitis risk: relation to epithelial ion transport and trypsin inhibitor gene mutations

BACKGROUND & AIMS

Nonalcoholic chronic pancreatitis is usually idiopathic and often associated with cystic fibrosis gene (CFTR) mutations. It is unknown whether pancreatitis risk correlates with having 1 or 2 CFTR mutations, abnormal epithelial ion transport, or mutations of other genes.

METHODS

We tested 39 patients with idiopathic chronic pancreatitis (mean age at diagnosis, 33 years) for common mutations of CFTR and of genes encoding a trypsin inhibitor (PSTI) and trypsinogen (PRSS1). To exclude hereditary pancreatitis, we initially relied on family history and subsequently tested for PRSS1 mutations. Twenty subjects were tested for rare CFTR mutations (DNA sequencing) and 11 were tested for extrapancreatic CFTR function (clinical and physiologic evaluation).

RESULTS

Mutations were identified in 24 of 39 subjects. Nine patients had cystic fibrosis-causing mutations, 8 of whom also had mild-variable mutations. Eight others had only mild-variable mutations. Nine subjects had the N34S PSTI mutation and 1 had hereditary pancreatitis (R122H, PRSS1). Pancreatitis risk was increased approximately 40-fold by having 2 CFTR mutations (P < 0.0001), 20-fold by having N34S (P < 0.0001), and 900-fold by having both (P < 0.0001). Subjects with 2 CFTR mutations had abnormal nasal epithelial ion transport and clinical findings suggesting residual CFTR function between that in cystic fibrosis and in carriers. By contrast, subjects with only PSTI mutations had normal CFTR function.

CONCLUSIONS

CFTR-related pancreatitis risk correlates with having 2 CFTR mutations and reduced extrapancreatic CFTR function. The N34S PSTI mutation increased risk separately. Testing for pancreatitis-associated CFTR and PSTI genotypes may be useful in nonalcoholic pancreatitis.

The bHLH transcription factor Mist1 is required to maintain exocrine pancreas cell organization and acinar cell identity

The pancreas is a complex organ that consists of separate endocrine and exocrine cell compartments. Although great strides have been made in identifying regulatory factors responsible for endocrine pancreas formation, the molecular regulatory circuits that control exocrine pancreas properties are just beginning to be elucidated. In an effort to identify genes involved in exocrine pancreas function, we have examined Mist1, a basic helix-loop-helix transcription factor expressed in pancreatic acinar cells. Mist1-null (Mist1(KO)) mice exhibit extensive disorganization of exocrine tissue and intracellular enzyme activation. The exocrine disorganization is accompanied by increases in p8, RegI/PSP, and PAP1/RegIII gene expression, mimicking the molecular changes observed in pancreatic injury. By 12 m, Mist1(KO) mice develop lesions that contain cells coexpressing acinar and duct cell markers. Analysis of the factors involved in cholecystokinin (CCK) signaling reveal inappropriate levels of the CCK receptor A and the inositol-1,4,5-trisphosphate receptor 3, suggesting that a functional defect exists in the regulated exocytosis pathway of Mist1(KO) mice. Based on these observations, we propose that Mist1(KO) mice represent a new genetic model for chronic pancreas injury and that the Mist1 protein serves as a key regulator of acinar cell function, stability, and identity.

[Alcohol and oxidative stress]

There is accumulating evidence pointing oxidative stress as a mechanism of ethanol toxicity. Oxidative stress takes place when the balance between the antioxidant defenses and the generation of reactive oxygen species (ROS) is tipped in favour of the latter. Ethanol metabolism is directly involved in the production of ROS, but ethanol also participated to the formation of an environment favourable to oxidative stress such as hypoxia, endotoxemia and cytokine release. Following ethanol intoxication, balance between prooxidants and antioxidants is disturbed to such an extent that it results in an oxidative damage of biomolecules. The ability of ethanol to induce peroxidation of membrane lipids is widely reviewed in literature. More recently it has also been described that ethanol can oxidize proteins and ADN. In this review, is also discussed the impairment of cellular function resulting from this situation of oxidative stress.

Expression of hepatocyte growth factor, keratinocyte growth factor and their receptors in experimental chronic pancreatitis

BACKGROUND

Hepatocyte (HGF) and Keratinocyte growth factors (KGF) are key factors of tissue organization and regeneration. These peptide growth factors and their receptors c-met and keratinocyte growth factor receptor (KGFR) are overexpressed in pancreatic cancer.

AIM

Expression and localization of ligands and receptors were investigated during the development of experimental chronic pancreatitis.

METHODS

Chronic pancreatitis was induced in rats by intravenous injection of dibutyltin dichloride. One to 60 days after treatment, the expression of growth factors and receptors was analysed by competitive polymerase chain reaction, Western blot analysis and immunohistochemistry.

RESULTS

HGF mRNA expression increased (10-fold) until days 7-14 followed by a decrease to control level. Expression of c-met mRNA constantly increased (15-fold). KGF and KGFR mRNA expression were increased after 14-28 days (5-fold) and then returned to control levels. mRNA expression patterns correlated with changes in the protein expression, whereas protein levels of KGF remained unchanged. Ligands were localized in mesenchymal cells and their receptors on epithelial cells.

CONCLUSIONS

The significant increase of HGF and c-met expression suggests an essential role of this growth factor in the morphological changes during the development of chronic pancreatitis. Changes in the expression of KGF and KGFR are less pronounced.

Role of TGF-beta1, 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)-beta 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-beta, 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-beta1 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-beta1, and MMP-2 in the pancreas was assessed by using a monoclonal antibody.

RESULTS

TGF-beta1 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-beta1 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-beta1 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.

Models of alcoholic liver disease in rodents: a critical evaluation

This article represents the proceedings of a workshop at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were J. Christian Bode and Hiroshi Fukui. The presentations were (1) Essentials and the course of the pathological spectrum of alcoholic liver disease in humans, by P. de la M. Hall; (2) Lieber-DeCarli liquid diet for alcohol-induced liver injury in rats, by C. S. Lieber and L. M. DeCarli; (3) Tsukamoto-French model of alcoholic liver injury, by S. W. French; (4) Animal models to study endotoxin-ethanol interactions, by K. O. Lindros and H. Järveläinen; and (5) Jejunoileal bypass operation in rats-A model for alcohol-induced liver injury? by Christiane Bode, Alexandr Parlesak, and J. Christian Bode.

The role of acetaldehyde in the actions of alcohol (update 2000)

BACKGROUND

Recent advances in the field of acetaldehyde (AcH) research have raised the need for a comprehensive review on the role of AcH in the actions of alcohol. This update is an attempt to summarize the available AcH research.

METHODS

The descriptive part of this article covers not only recent research but also the development of the field. Special emphasis is placed on mechanistic analyses, new hypotheses, and conclusions.

RESULTS

Elevated AcH during alcohol intoxication causes alcohol sensitivity, which involves vasodilation associated with increased skin temperature, subjective feelings of hotness and facial flushing, increased heart and respiration rate, lowered blood pressure, sensation of dry mouth or throat associated with bronchoconstriction and allergy reactions, nausea and headache, and also reinforcing reactions like euphoria. These effects seem to involve catecholamine, opiate peptide, prostaglandin, histamine, and/or kinin mechanisms. The contribution of AcH to the pathological consequences of chronic alcohol intake is well established for different forms of cancer in the digestive tract and the upper airways. AcH seems to play a role in the etiology of liver cirrhosis. AcH may have a role in other pathological developments, which include brain damage, cardiomyopathy, pancreatitis, and fetal alcohol syndrome. AcH creates both unpleasant aversive reactions that protect against excessive alcohol drinking and euphoric sensations that may reinforce alcohol drinking. The protective effect of AcH may be used in future treatments that involve gene therapy with or without liver transplantation.

CONCLUSIONS

AcH plays a role in most of the actions of alcohol. The individual variability in these AcH-mediated actions will depend on the genetic polymorphism, not only for the alcohol and AcH-metabolizing enzymes but also for the target sites for AcH actions. The subtle balance between aversive and reinforcing, protecting and promoting factors will determine the overall behavioral and pathological developments.

Mutations of the cystic fibrosis gene in patients with chronic pancreatitis

OBJECTIVE

Several studies have reported an increased frequency of cystic fibrosis gene mutations in idiopathic but not in alcoholic chronic pancreatitis. The impact of cystic fibrosis gene mutations on the long-term course of chronic pancreatitis has not been analyzed. The aim of our study was to determine the frequency of cystic fibrosis gene mutations in patients with chronic pancreatitis with long-term follow-up and to see whether patients with mutations have a clinically different natural course compared to those without mutations.

METHODS

Eighty two patients with chronic pancreatitis and 11 patients with recurrent acute pancreatitis of our well defined pancreatitis cohort were screened for the 31 most common cystic fibrosis gene mutations. The impact of cystic fibrosis gene mutations on the long-term course of chronic pancreatitis was assessed.

RESULTS

A cystic fibrosis gene mutation was detected in five of 49 patients with alcoholic chronic pancreatitis (10.2%; 2.3 times the expected frequency) and in three of 14 patients with idiopathic-juvenile chronic pancreatitis (21.4%; 4.8 times the expected frequency). No mutations were found in the remaining patients with chronic pancreatitis of rare causes, hereditary pancreatitis, and recurrent acute pancreatitis. The frequency of pancreatic calcifications was significantly higher in patients with alcoholic chronic pancreatitis without mutations. This result was not confirmed in patients with idiopathic-juvenile chronic pancreatitis. The duration of pain and the frequency of exocrine and endocrine insufficiency was comparable in both subgroups irrespective of the mutation status.

CONCLUSION

Our data indicate a significantly increased frequency of cystic fibrosis gene mutations both in patients with alcoholic and idiopathic-juvenile chronic pancreatitis. The natural course was similar in patients with mutations compared to those without mutations.

Chronic ethanol consumption induces gene expression of pancreatic monitor peptide, but not SPINK1/PSTI-56, in rats

The primary factors that predispose humans to the development of alcoholic pancreatitis are unknown. One of the earliest observations in humans in whom this disease develops is pancreatic hypersecretion caused by unknown mechanisms. Messenger RNA (mRNA) differential display was performed in a rat model to investigate the molecular mechanisms associated with ethanol-induced pancreatic hypersecretion. Male Wistar rats were pair-fed Lieber-DeCarli diets with or without ethanol for 7 days or 4 weeks. Total RNA was extracted from the pancreas and its neurohormonal control sites. Differentially expressed complementary DNA (cDNA) tags were isolated, cloned, and sequenced. One 248-bp cDNA was consistently and strongly induced in the pancreata of rats fed ethanol for 4 weeks. The sequence was highly homologous to both rat pancreatic monitor peptide (MP) and pancreatic secretory trypsin inhibitor (PSTI-56), also known as serine protease inhibitor, Kazal type 1 (SPINK1). Confirmatory reverse-transcription-polymerase chain reaction showed that PSTI-56 expression remained unchanged, whereas MP mRNA levels were elevated more than four times in the pancreata of ethanol-fed rats. These results indicate that long-term ethanol ingestion increases MP mRNA levels in the rat pancreas. Because MP stimulates cholecystokinin release and cholecystokinin is an important stimulant of pancreatic secretion, the enhanced MP gene expression may contribute to pancreatic hypersecretion.

Identification of mediators stimulating proliferation and matrix synthesis of rat pancreatic stellate cells

The aim of this study was to identify fibrogenic mediators stimulating activation, proliferation, and/or matrix synthesis of rat pancreatic stellate cells (PSC). PSC were isolated from the pancreas of normal Wistar rats and from rats with cerulein pancreatitis. Cell activation was demonstrated by immunofluorescence microscopy of smooth muscle alpha-actin (SMA) and real-time quantitative RT-PCR of SMA, fibronectin, and transforming growth factor (TGF)-beta(1). Proliferation was measured by bromodeoxyuridine incorporation. Matrix synthesis was demonstrated on the protein and mRNA level. Within a few days in primary culture, PSC changed their phenotype from fat-storing to SMA-positive myofibroblast-like cells expressing platelet-derived growth factor (PDGF) alpha- and PDGF beta-receptors. TGF-beta(1) and tumor necrosis factor (TNF)-alpha accelerated the change in the cells' phenotype. Addition of 50 ng/ml PDGF and 5 ng/ml basic fibroblast growth factor (bFGF) to cultured PSC significantly stimulated cell proliferation (4.37 +/- 0.49- and 2.96 +/- 0.39-fold of control). Fibronectin synthesis calculated on the basis of DNA was stimulated by 5 ng/ml bFGF (3.44 +/- 1.13-fold), 5 ng/ml TGF-beta(1) (2.46 +/- 0.89-fold), 20 ng/ml PDGF (2.27 +/- 0.68-fold), and 50 ng/ml TGF-alpha (1.87 +/- 0.19-fold). As shown by RT-PCR, PSC express predominantly the splice variant EIII-A of fibronectin. Immunofluorescence microscopy and Northern blot confirmed that in particular bFGF and TGF-beta(1) stimulated the synthesis of fibronectin and collagens type I and III. In conclusion, our data demonstrate that 1) TGF-beta(1) and TNF-alpha accelerate the change in the cell phenotype, 2) PDGF represents the most effective mitogen, and 3) bFGF, TGF-beta(1), PDGF, and, to a lesser extent, TGF-alpha stimulate extracellular matrix synthesis of cultured rat PSC.

Involvement of cyclooxygenase-2 in the potentiation of allyl alcohol-induced liver injury by bacterial lipopolysaccharide

Bacterial endotoxin (lipopolysaccharide; LPS) augments the hepatotoxicity of a number of xenobiotics including allyl alcohol. The mechanism for this effect is known to involve the inflammatory response elicited by LPS. Upregulation of cyclooxygenase-2 (COX-2) and production of eicosanoids are important aspects of inflammation, therefore studies were undertaken to investigate the role of COX-2 in LPS-induced enhancement of liver injury from allyl alcohol. Rats were pretreated (iv) with a noninjurious dose of LPS or sterile saline vehicle and 2 h later were treated (ip) with a noninjurious dose of allyl alcohol or saline vehicle. COX-2 mRNA was determined by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR), and liver injury was assessed from activities in serum of alanine and aspartate aminotransferases (ALT and AST, respectively) and from histology. Liver injury was observed only in rats cotreated with LPS and allyl alcohol. Serum ALT activity was increased by 4 h after administration of LPS and continued to increase through 8 h. COX-2 mRNA was detectable at low levels in livers from rats receiving only the vehicles at any time up to 8 h. Expression of COX-2 mRNA was increased by 30 min after administration of LPS and remained elevated through 6 h. Allyl alcohol treatment alone caused an increase in COX-2 mRNA at 4 h (2 h after allyl alcohol) that lasted less than 2 h. In livers from rats cotreated with LPS and allyl alcohol, levels of COX-2 mRNA were greater than levels seen with either LPS or allyl alcohol alone. The increased expression of COX-2 mRNA was accompanied by an increase in the concentration of prostaglandin (PG) D(2) in plasma. Plasma PGD(2) concentration was increased to a greater extent in rats treated with LPS plus allyl alcohol compared to allyl alcohol or LPS alone. Pretreatment with the COX-2 selective inhibitor, NS-398, abolished the increase in plasma PGD(2) and reduced the increase in ALT and AST activities observed in rats cotreated with LPS and allyl alcohol. NS-398 did not affect liver injury from allyl alcohol alone administered at a larger, hepatotoxic dose. In addition, ibuprofen, a nonselective inhibitor of cyclooxygenases, did not protect against liver injury from LPS plus allyl alcohol. In isolated hepatocytes PGD(2), but not PGE(2), reduced the concentration of allyl alcohol required to cause half-maximal cytotoxicity. These results suggest that products of COX-2 play a role in the augmentation of allyl alcohol-induced liver injury by LPS.

The antiestrogen toremifene protects against alcoholic liver injury in female rats

BACKGROUND/AIMS

Females are generally considered to be more susceptible to alcohol-induced liver injury than males. To elucidate whether gonadal hormones are involved, female rats were chronically treated with ethanol and with an antiestrogen.

METHODS

Ethanol was administered in a low-carbohydrate liquid diet. Estrogen action was blocked by daily intubation of toremifene, a non-hepatotoxic second generation estrogen receptor antagonist.

RESULTS

The female rats consuming intoxicating amounts of ethanol diet for 6 weeks developed massive microvesicular/macrovesicular steatosis, frequent inflammatory foci and spotty necrosis. Serum alanine aminotransferase increased 7-fold. Toremifene treatment did not affect steatosis, but significantly reduced inflammation and necrosis. Ethanol increased the expression of CD14 and tumor necrosis factor- (TNF) alpha mRNA and also the production of TNF-alpha by isolated Kupffer cells, but toremifene had no significant counteracting effect. However, toremifene significantly alleviated both ethanol induction of the pro-oxidant enzyme CYP2E1 and ethanol reduction of the oxidant-protective enzyme Se-glutathione peroxidase.

CONCLUSIONS

The partial protection by toremifene against ethanol-induced liver lesions suggests a pathogenic contribution of estrogens, possibly associated with an oxygen radical mediated mechanism.

Isolation, long-term culture, and characterization of rat pancreatic fibroblastoid/stellate cells

Investigation of pancreatic interstitial fibroblasts has proven difficult in situ. We have established a method for the isolation of pancreatic fibroblastoid/stellate cells by outgrowth from pancreatic tissue explanted into culture dishes. This technique gives a high yield of viable cells from small tissue samples. Outgrown fibroblastoid cells were established as a primary cell line and characterized during long-term culture. We investigated the development of stellate cell markers, i.e. fat storage, expression of desmin, and alpha-smooth muscle actin (alphaSMA), over weeks in culture. AlphaSMA, investigated by indirect immunofluorescence staining and Western blot analysis, revealed a constant rise in expression during routine culture. After 13 passages. approximately 100% of cells were positive for alphaSMA expression, indicating a myofibroblast type of differentiation in vitro.

Linkage of oxidative and nonoxidative ethanol metabolism in the pancreas and toxicity of nonoxidative ethanol metabolites for pancreatic acinar cells

BACKGROUND

Alcohol abuse is a major cause of pancreatic damage. Recent experimental evidence suggests that fatty acid ethyl esters (FAEE), nonoxidative ethanol metabolites, injure pancreatic acinar cells. Linkage between oxidative and nonoxidative metabolism of ethanol in the pancreas may contribute to increased FAEE levels.

METHODS

To study the association between oxidative and nonoxidative ethanol metabolism, FAEE concentration and FAEE synthase activity in rat pancreatic and liver homogenates incubated with ethanol were evaluated with and without inhibitors of oxidative ethanol metabolism. For toxicity studies, trypsinogen activation peptide synthesis as a measure of pancreatic cell injury was quantitated in unstimulated and cerulein-stimulated isolated pancreatic acinar cells incubated with ethanol or FAEE.

RESULTS

Inhibition of oxidative ethanol metabolism results in a 2- to 3-fold increase in nonoxidative ethanol metabolism to FAEE in pancreas and in liver. Both ethanol and FAEE induce increased intracellular trypsinogen activation by more than 50% in the presence of physiologic concentrations of cerulein in vitro.

CONCLUSIONS

These findings demonstrate that the inhibition of oxidative ethanol metabolism results in an increase in flux through the nonoxidative pathway and support the proposition that alcohol-induced pancreatic injury is mediated at least in part by FAEE, which are important products of pancreatic ethanol metabolism.

Expression of tumor necrosis factor-alpha, interleukin-6, and interferon-gamma in spontaneous chronic pancreatitis in the WBN/Kob rat

To clarify the pathophysiological significance of cytokines in chronic pancreatitis (CP), we analyzed tissue expressions of various cytokines in the onset and progression of spontaneous CP in the WBN/Kob rat. Four-week-old male WBN/Kob rats were fed a special pellet diet (MB-3) for 20 weeks, and 6 rats were killed every 4 weeks. Pathologically, CP occurred at 12 weeks and progressed thereafter. The inflammation and fibrosis peaked at 12 and 16 weeks, respectively. By semiquantitative reverse transcription-polymerase chain reaction, the expression of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and interferon (IFN)-gamma mRNAs peaked at 8, 12, and 16 weeks, respectively. Immunohistochemistry showed IL-6 expression in infiltrating inflammatory cells and vascular endothelial cells, whereas TNF-alpha was expressed in both acinar and infiltrating cells. IFN-gamma was localized to acinar, infiltrating and ductal cells, and its expression intensity showed significant correlation with those of fibrosis, type III collagen and alpha-smooth muscle actin. The in situ hybridization results were consistent with the RT-PCR data. These results suggest that tissue expressions of TNF-alpha and IL-6 are involved in the onset of pancreatitis and that IFN-gamma expression is related to the progression of CP.

Models of alcoholic liver disease in rodents: a critical evaluation

This article represents the proceedings of a workshop at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were J. Christian Bode and Hiroshi Fukui. The presentations were (1) Essentials and the course of the pathological spectrum of alcoholic liver disease in humans, by P. de la M. Hall; (2) Lieber-DeCarli liquid diet for alcohol-induced liver injury in rats, by C. S. Lieber and L. M. DeCarli; (3) Tsukamoto-French model of alcoholic liver injury, by S. W. French; (4) Animal models to study endotoxin-ethanol interactions, by K. O. Lindros and H. Järveläinen; and (5) Jejunoileal bypass operation in rats-A model for alcohol-induced liver injury? by Christiane Bode, Alexandr Parlesak, and J. Christian Bode.

The role of acetaldehyde in the actions of alcohol (update 2000)

BACKGROUND

Recent advances in the field of acetaldehyde (AcH) research have raised the need for a comprehensive review on the role of AcH in the actions of alcohol. This update is an attempt to summarize the available AcH research.

METHODS

The descriptive part of this article covers not only recent research but also the development of the field. Special emphasis is placed on mechanistic analyses, new hypotheses, and conclusions.

RESULTS

Elevated AcH during alcohol intoxication causes alcohol sensitivity, which involves vasodilation associated with increased skin temperature, subjective feelings of hotness and facial flushing, increased heart and respiration rate, lowered blood pressure, sensation of dry mouth or throat associated with bronchoconstriction and allergy reactions, nausea and headache, and also reinforcing reactions like euphoria. These effects seem to involve catecholamine, opiate peptide, prostaglandin, histamine, and/or kinin mechanisms. The contribution of AcH to the pathological consequences of chronic alcohol intake is well established for different forms of cancer in the digestive tract and the upper airways. AcH seems to play a role in the etiology of liver cirrhosis. AcH may have a role in other pathological developments, which include brain damage, cardiomyopathy, pancreatitis, and fetal alcohol syndrome. AcH creates both unpleasant aversive reactions that protect against excessive alcohol drinking and euphoric sensations that may reinforce alcohol drinking. The protective effect of AcH may be used in future treatments that involve gene therapy with or without liver transplantation.

CONCLUSIONS

AcH plays a role in most of the actions of alcohol. The individual variability in these AcH-mediated actions will depend on the genetic polymorphism, not only for the alcohol and AcH-metabolizing enzymes but also for the target sites for AcH actions. The subtle balance between aversive and reinforcing, protecting and promoting factors will determine the overall behavioral and pathological developments.