Peter Feick

The biological responses to resveratrol and other polyphenols from alcoholic beverages

Although excessive consumption of ethanol in alcoholic beverages causes multi-organ damage, moderate consumption, particularly of red wine, is protective against all-cause mortality. These protective effects could be due to one or many components of the complex mixture of bioactive compounds present in red wine including flavonols, monomeric and polymeric flavan-3-ols, highly colored anthocyanins as well as phenolic acids and the stilbene polyphenol, resveratrol. The therapeutic potential of resveratrol, firstly in cancer chemoprevention and then later for cardioprotection, has stimulated many studies on the possible mechanisms of action. Further indications for resveratrol have been developed, including the prevention of age-related disorders such as neurodegenerative diseases, inflammation, diabetes, and cardiovascular disease. These improvements are remarkably similar yet there is an important dichotomy: low doses improve cell survival as in cardio- and neuro-protection yet high doses increase cell death as in cancer treatment. Fewer studies have examined the responses to other components of red wine, but the results have, in general, been similar to resveratrol. If the nonalcoholic constitutents of red wine are to become therapeutic agents, their ability to get to the sites of action needs to be understood. This mini-review summarizes recent studies on the possible mechanisms of action, potential therapeutic uses, and bioavailability of the nonalcoholic constituents of alcoholic beverages, in particular resveratrol and other polyphenols.

Hepcidin is localised in gastric parietal cells, regulates acid secretion and is induced by Helicobacter pylori infection

Backgrounds and aims Hepcidin is an antimicrobial peptide and the central regulator of iron metabolism. Given that hepcidin was shown to be expressed in a variety of extrahepatic tissues and that stomach plays a role in iron absorption and in defence against infections, this study analysed the importance of hepcidin in the stomach. Methods Expression and localisation of gastric hepcidin was studied by quantitative RT-PCR, western blot, immunofluorescence and in situ hybridisation. Regulation of gastric hepcidin expression was analysed both in vitro and in vivo. Hepcidin wild-type (WT) and knockout (KO) animals were used to determine the impact of hepcidin on gastric bacterial overgrowth as well as gastric acid secretion. Results Hepcidin was abundantly expressed in the gastric fundus and corpus of all tested species. Treatment of AGS cells with ferric nitrilotriacetate solution downregulated hepcidin expression levels, while desferroxamine, interleukin 6 and Helicobacter pylori infection upregulated it. In humans, gastric hepcidin expression was elevated during H pylori infection and normalised after successful eradication. Gastric hepcidin is localised in parietal cells that are indispensable for gastric acid secretion. Comparisons of WT and hepcidin KO mice revealed that acid secretion in hepcidin-deficient mice is markedly reduced and is associated with gastric bacterial overgrowth, expression changes in multiple factors involved in acid secretion (Atp4a, Cck2r,Gas, Sst and Sst2r) and with reduced circulating gastrin levels. In WT mice, pantoprazole activated and histamine downregulated hepcidin expression levels. Conclusions Hepcidin is a product of parietal cells regulating gastric acid production and may contribute to development of gastric ulcers under stress conditions.

Isoform of fibronectin mediates bone loss in patients with primary biliary cirrhosis by suppressing bone formation.

Osteoporosis is a major cause of morbidity and decreased quality of life in patients with chronic cholestatic liver disease. It is established that this osteoporosis results from decreased bone formation, but the mechanisms for the interaction between liver and bone remain elusive. The aim of this study was to test the hypothesis that an increase in the production of cellular fibronectins during liver disease may result in decreased osteoblast‐mediated mineralization and thus explain the decrease in bone formation. We performed a prospective cross‐sectional study in patients with primary biliary cirrhosis and matched controls, followed by experiments on human and mouse osteoblasts in culture and injections in mice in vivo. In patients with primary biliary cirrhosis, the oncofetal domain of fibronectin correlated significantly with the decrease in osteocalcin, a marker of bone formation (r = −0.57, p < 0.05). In vitro, amniotic fluid fibronectin (aFN) containing mainly the oncofetal domain and EIIIA domain resulted in decreased osteoblast‐mediated mineralization in human osteoblasts (69% decrease at 100 μg/ml; p < 0.01) and mouse osteoblasts (71% decrease; p < 0.05). Removing the EIIIA domain from aFN similarly suppressed mineralization by osteoblasts (78% decrease; p < 0.05). Injection of labeled aFN in mice showed that it infiltrates the bone, and its administration over 10 days resulted in decreased trabecular BMD (17% drop; p < 0.05), mineralizing surface (30% drop; p < 0.005), and number of osteoblasts (45% drop; p < 0.05). Increased production of a fibronectin isoform containing the oncofetal domain and its release in the circulation in patients with primary biliary cirrhosis is at least partially responsible for the decrease in bone formation seen in these patients. This establishes that a molecule that has thus far been viewed as an extracellular matrix protein exerts hormone‐like actions.

Circulating fibronectin isoforms predict the degree of fibrosis in chronic hepatitis C.

Abstract Objective. Hepatic stellate cells only produce fibronectin isoforms in disease states. The isoform-defining domains can be detected in the blood circulation. This study examines whether circulating levels of fibronectin isoforms show a relationship with liver fibrosis on histology in patients with chronic hepatitis C. Material and methods. In a prospective study, 50 patients with chronic hepatitis C who underwent a liver biopsy were compared to 50 matched controls and 35 patients with other liver conditions. Results. Circulating levels of the fibronectin isoforms were significantly higher in patients with chronic hepatitis C compared to healthy controls [oncofetal fibronectin (oFN) 2.45 ± 0.17 versus 1.76 ± 0.16 mg/l, P < 0.005; extra domain-A (EDA) 1.05 ± 0.06 versus 0.86 ± 0.06 mg/l, P < 0.05; and extra domain-B (EDB) 14.55 ± 0.74 versus 9.31 ± 0.58 mg/l, P < 0.001], even though total fibronectin was lower (198.9 ± 3.5 versus 343.6 ± 14.5 mg/l, P < 0.001). A correlation with the fibrosis score was found for both oFN (r = 0.46, P < 0.005) and EDA (r = 0.51, P < 0.001). The combination of an elevation in both markers (oFN and EDA) in the upper quartile was associated with a specificity of > 99% for predicting significant fibrosis (stages 2–4) and 95% for predicting advanced fibrosis (stages 3–4). A combination of decreased values in the lowest tertile for both markers had a specificity of 94% for excluding significant fibrosis. Based on these findings, 30% of the patients scheduled for a liver biopsy could be correctly classified as having or not having significant fibrosis. The remainder would have to proceed with a biopsy. Conclusion. Circulating fibronectin isoforms produced by activated stellate cells represent a viable marker for the presence of significant fibrosis or a lack thereof.

Effect of Non-Alcoholic Compounds of Alcoholic Drinks on the Pancreas

Over the past 30 years the role of alcohol (ethanol) in the development of acute and chronic pancreatitis has been intensively investigated. However, ethanol is generally consumed in form of alcoholic beverages which contain numerous non-alcoholic compounds. At least on gastric acid secretion it has been convincingly demonstrated that alcohol and alcoholic beverages have markedly different effects. In the present article, we provide an overview about the effect of different non-alcoholic constituents of alcoholic beverages on the pancreas and their possible interaction with molecular mechanisms leading to ‘alcoholic’ pancreatitis. The present data indicate that pancreatic enzyme secretion in humans is stimulated by non-alcoholic constituents of beer which are generated by alcoholic fermentation of glucose. In addition, it has been shown that natural phenolic compounds (e.g. quercetin, resveratrol) of alcoholic beverages exert different effects on the pancreasin vitro, such as inhibition of pancreatic enzyme output, of pancreatic stellate cell activation and of pancreatic cancer growth as well as protective effects against oxidative stress and on experimental induced acute pancreatitis in rats. However, it should be pointed out that alcoholic beverages contain much more non-alcoholic ingredients. Since the effects of these are still unknown, caution is required in attempting to define alcoholic etiology of pancreatitis without considering the effect of non-alcoholic compounds of alcoholic beverages.

Beer and its non-alcoholic compounds: role in pancreatic exocrine secretion, alcoholic pancreatitis and pancreatic carcinoma.

In this article we provide an overview of the newest data concerning the effect of non-alcoholic constituents of alcoholic beverages, especially of beer, on pancreatic secretion, and their possible role in alcoholic pancreatitis and pancreatic carcinoma. The data indicate that non-alcoholic constituents of beer stimulate pancreatic enzyme secretion in humans and rats, at least in part, by direct action on pancreatic acinar cells. Some non-alcoholic compounds of beer, such as quercetin, resveratrol, ellagic acid or catechins, have been shown to be protective against experimentally induced pancreatitis by inhibiting pancreatic secretion, stellate cell activation or by reducing oxidative stress. Quercetin, ellagic acid and resveratrol also show anti-carcinogenic potential in vitro and in vivo. However, beer contains many more non-alcoholic ingredients. Their relevance in beer-induced functional alterations of pancreatic cells leading to pancreatitis and pancreatic cancer in humans needs to be further evaluated.

Complement activation correlates with liver necrosis and fibrosis in chronic hepatitis C.

Chronic hepatitis C viral infection modulates complement. The aim of this study was to determine whether complement analysis predicts liver inflammation and fibrosis in patients with chronic hepatitis C. 50 chronic hepatitis C patients who underwent a liver biopsy were compared to 50 healthy controls and 35 patients with various liver diseases. Total plasma complement activity (CH50) in plasma was diminished in hepatitis C patients suggesting complement activation. This decrease correlated with increased necrosis (r = -0.24, p < 0.05), and patients with levels below the normal range had a higher METAVIR activity score reflecting enhanced inflammation. SC5b-9, a marker of complement activation, correlated with inflammation (r = 0.40, p < 0.05), activity (r = 0.42, p < 0.05), and fibrosis scores (r = 0.49, p < 0.05). Finally, the prevalence of C1q auto-antibodies was higher in hepatitis C patients, and their presence was associated with increased inflammation and seemed to affect fibrosis. We conclude that complement-induced liver inflammation contributes to fibrosis in patients with chronic hepatitis C.

Alcohol and Smoking

The WHO ranks smoking and alcohol consumption as the first and third leading causes of the global burden of disease in industrialized countries, using disability-adjusted life years (DALYs) as a combined measure of premature death and disability. Smoking is responsible for 12.2% of all DALYs and alcohol consumption for 9.2%. For example in Germany, annually 110,000–140,000 humans die prematurely because of cigarette smoking and 40,000 because of alcohol drinking. In Europe and the USA, more than 20% of all hospitalized men and more than 9% of all hospitalized women suffer from alcohol-associated diseases. In Germany, about 2.0 million people in the age group 18–64 years (3.8% of all Germans) are alcohol abusers and 1.3 million people (2.4%) are alcohol-dependent. Alcohol can cause acute as well as chronic damage in nearly all body organs. Smoking damages also nearly every human body organ and is worldwide the most important single preventable health risk factor as well as the main cause for premature mortality in industrial countries. One third of the adult Germans as well as of the world population are active smokers; men smoke more frequently than women (34.0 vs. 25.1%). In this review a short overview will be given on the most important deleterious effects of alcohol and smoking. The most recent data about the pathophysiological relevance of non-alcoholic compounds of alcoholic beverages will also be discussed.

Beer-Induced Pancreatic Enzyme Secretion: Characterization of Some Signaling Pathways and of the Responsible Nonalcoholic Compounds

BACKGROUND Various alcoholic beverages have different effects on pancreatic enzyme secretion in vivo and in vitro. Recently we demonstrated that beer dose-dependently induces amylase release of rat pancreatic acinar cells, whereas pure ethanol and other alcoholic beverages have no effect. The aims of this study were to: (1) investigate the involved signaling pathways in the beer-induced enzyme secretion of rat pancreatic acinar cells and (2) characterize the responsible nonalcoholic compounds from beer. METHODS Rat pancreatic AR4-2J cells were differentiated by dexamethasone treatment for 72 hours. After incubation of cells with 1 to 10% (v/v) beer (containing 4.7% v/v ethanol) in the absence or presence of the maximal effective concentration of cholecystokinin (CCK) (100 nM) for 60 minutes, protein secretion was measured using amylase activity assay. To study the involved signaling pathways, cells were pretreated with selective inhibitors or the fluorescent dye Fura2/AM for 15 and 30 minutes, respectively. To characterize the responsible compounds, beer was distilled, lyophilized, dialyzed, or treated with proteases prior stimulation of the cells. Extract of barley was prepared by boiling the crop and subsequent filtration. RESULTS Stimulation with 5% and 10% beer (v/v) significantly (p < 0.001) increased maximally CCK-induced amylase by 55 +/- 25% and 56 +/- 37%, respectively. By using selective antagonists, we found that inhibition of phospholipase C (PLC) and inositol 1,4,5-trisphosphate-receptor binding reduced beer-induced amylase release, whereas inhibition of protein kinase C, adenylate cyclase, and protein kinase A had no significant effect. Using the fluorescent Ca(2+) indicator Fura-2/AM revealed that beer induces an increase of cytosolic free Ca(2+) concentration. Stimulation of AR4-2J cells with preproducts of beer and fermented glucose indicated that the stimulatory substances from beer derived from barley and are not produced during alcoholic fermentation. Furthermore, the stimulants from beer are thermostable, nonvolatile substances with a molecular weight higher than 15 kDa. CONCLUSIONS Beer-induced enzyme secretion of AR4-2J cells is, at least in part, mediated by the activation of PLC and subsequent Ca(2+) release from internal stores. However, the additive effect of beer on CCK-induced amylase release suggests that additional signaling pathways are involved. The yet unknown stimulants of pancreatic enzyme secretion originate from barley and their stimulatory potential is maintained during the process of malting and brewing.

Beer But Not Wine, Hard Liquors, or Pure Ethanol Stimulates Amylase Secretion of Rat Pancreatic Acinar Cells In Vitro

BACKGROUND In contrast to pure ethanol, the effect of alcoholic beverages on the exocrine pancreas is greatly unknown. Besides ethanol, alcoholic beverages contain numerous nonalcoholic constituents which might have pathophysiological effects on the pancreas. The aim of the present study was to investigate whether some commonly used alcoholic beverages and pure ethanol influence the main function of rat pancreatic acinar cells, i.e., enzyme output in vitro. METHODS Rat pancreatic AR4-2J cells were differentiated by dexamethasone treatment for 72 hours and freshly isolated pancreatic acini were prepared from Sprague-Dawley rats using collagenase digestion. After incubation of cells in the absence or presence of 1 to 10% (v/v) beer (containing 4.7% v/v ethanol), 10% (v/v) wine (containing 10.5 to 12.5% v/v ethanol), 10% (v/v) hard liquor (such as whisky, rum, and gin), or of the corresponding ethanol concentrations (4.03 to 80.6 mM) for 60 minutes, protein secretion was measured using amylase activity assay. RESULTS Incubation of AR4-2J cells with beer caused a dose-dependent stimulation of basal amylase secretion that was significant at doses of beer above 0.5% (v/v). Stimulation with 10% (v/v) beer induced 92.7 +/- 25.2% of maximal amylase release in response to the most effective cholecystokinin (CCK) concentration (100 nM). In contrast, ethanol (up to 80.6 mM) did neither stimulate nor inhibit basal amylase release. Lactate dehydrogenase measurement after treatment of AR4-2J cells with beer for 24 hours indicated that the increase of amylase release was not due to cell membrane damage. Wine and hard liquor had no effect on basal amylase secretion neither diluted to the ethanol concentration of beer nor undiluted. In freshly isolated rat pancreatic acinar cells beer dose-dependently stimulated amylase secretion in a similar manner as in AR4-2J cells. CONCLUSIONS Our data demonstrate that beer dose-dependently increases amylase output. Since neither ethanol nor the other alcoholic beverages tested caused stimulation of amylase release, our findings indicate that nonalcoholic constituents specific for beer are responsible for this increase. These as yet unknown compounds have to be identified and considered in further studies of ethanol-induced pathological and functional changes of the pancreas.