Individual susceptibility to alcoholic pancreatitis

Critical thresholds: key to unlocking the door to the prevention and specific treatments for acute pancreatitis

Acute pancreatitis (AP), an acute inflammatory disorder of the exocrine pancreas, is one of the most common gastrointestinal diseases encountered in emergency departments with no specific treatments. Laboratory-based research has formed the cornerstone of endeavours to decipher the pathophysiology of AP, because of the limitations of such study in human beings. While this has provided us with substantial understanding, we cannot answer several pressing questions. These are: (a) Why is it that only a minority of individuals with gallstones, or who drink alcohol excessively, or are exposed to other causative factors develop AP? (b) Why do only some develop more severe manifestations of AP with necrosis and/or organ failure? (c) Why have we been unable to find an effective therapeutic for AP? This manuscript provides a state-of-the-art review of our current understanding of the pathophysiology of AP providing insights into the unanswered clinical questions. We describe multiple protective factors operating in most people, and multiple stressors that in a minority induce AP, independently or together, via amplification loops. We present testable hypotheses aimed at halting progression of severity for the development of effective treatments for this common unpredictable disease.

Diagnosis and Management of Chronic Pancreatitis: A Review

IMPORTANCE

Chronic pancreatitis (CP) is a chronic inflammatory and fibrotic disease of the pancreas with a prevalence of 42 to 73 per 100 000 adults in the United States.

OBSERVATIONS

Both genetic and environmental factors are thought to contribute to the pathogenesis of CP. Environmental factors associated with CP include alcohol abuse (odds ratio [OR], 3.1; 95% CI, 1.87-5.14) for 5 or more drinks per day vs abstainers and light drinkers as well as smoking (OR, 4.59; 95% CI, 2.91-7.25) for more than 35 pack-years in a case-control study involving 971 participants. Between 28% to 80% of patients are classified as having "idiopathic CP." Up to 50% of these individuals have mutations of the trypsin inhibitor gene (SPINK1) or the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Approximately 1% of people diagnosed with CP may have hereditary pancreatitis, associated with cationic trypsinogen (PRSS1) gene mutations. Approximately 80% of people with CP present with recurrent or chronic upper abdominal pain. Long-term sequelae include diabetes in 38% to 40% and exocrine insufficiency in 30% to 48%. The diagnosis is based on pancreatic calcifications, ductal dilatation, and atrophy visualized by imaging with computed tomography, magnetic resonance imaging, or both. Endoscopic ultrasound can assist in making the diagnosis in patients with a high index of suspicion such as recurrent episodes of acute pancreatitis when imaging is normal or equivocal. The first line of therapy consists of advice to discontinue use of alcohol and smoking and taking analgesic agents (nonsteroidal anti-inflammatory drugs and weak opioids such as tramadol). A trial of pancreatic enzymes and antioxidants (a combination of multivitamins, selenium, and methionine) can control symptoms in up to 50% of patients. Patients with pancreatic ductal obstruction due to stones, stricture, or both may benefit from ductal drainage via endoscopic retrograde cholangiopancreatography (ERCP) or surgical drainage procedures, such as pancreaticojejunostomy with or without pancreatic head resection, which may provide better pain relief among people who do not respond to endoscopic therapy.

CONCLUSIONS AND RELEVANCE

Chronic pancreatitis often results in chronic abdominal pain and is most commonly caused by excessive alcohol use, smoking, or genetic mutations. Treatment consists primarily of alcohol and smoking cessation, pain control, replacement of pancreatic insufficiency, or mechanical drainage of obstructed pancreatic ducts for some patients.

Meta-analysis of the impact of SPINK1 p.N34S gene variation in Caucasic patients with chronic pancreatitis. An update

BACKGROUND

SPINK1 p.N34S gene variation is one of the endogenous factors which seem to be associated with chronic pancreatitis (CP). However, in literature there is no clear agreement regarding its contribution in different ethnicity and CP etiologies.

AIM

To investigate the role of SPINK1 p.N34S gene variation in CP patients with European origin by means of meta-analysis.

METHODS

Literature search was conducted and case-control studies evaluating Caucasian population, published between May 2007 and May 2015, were included. We also included Caucasian selected studies analyzed in previous meta-analysis. We carried out meta-analysis including all selected studies. After that, we performed two additional meta-analyses considering the incidence of SPINK1 p.N34S gene variation in alcoholic or in idiopathic CP patients vs control group.

RESULTS

Twenty-five studies were included and the total number of subjects was 8800 (2981 cases and 5819 controls). The presence of p.N34S variation increased nine times the overall CP risk in population of European origin [OR 9.695 (CI 95% 7.931-11.851)]. Also, the contribution of SPINK1 in idiopathic pancreatitis [OR 13.640 (CI 95% 8.858-21.002)] was found to be higher than in alcoholic CP [5.283 (CI 95% 3.449-8.092)].

CONCLUSION

The association between SPINK1 p.N34S gene variation and CP is confirmed. Also, we confirmed that the idiopathic etiology needs a better definition by means of genetic analysis.

Low Alcohol and Cigarette Use Is Associated to the Risk of Developing Chronic Pancreatitis

OBJECTIVES

The aim of this study was to investigate the contribution of smoking and alcohol intake and pancreas divisum on the risk of developing chronic pancreatitis (CP).

METHODS

Consecutive patients with CP who underwent secretin-enhanced magnetic resonance cholangiopancreatography were compared with consecutive patients without pancreatic disease who underwent secretin-enhanced magnetic resonance cholangiopancreatography for irritable bowel syndrome.

RESULTS

We enrolled 145 consecutive CP patients and 103 irritable bowel syndrome patients from 2010 to 2014. In a univariate analysis, statistically significant differences in sex, mean age, and the duration and amount of cigarette and alcohol use were found. Per a receiver operating characteristic curve analysis, thresholds for cigarette and alcohol consumption were, respectively, 5.5 cigarettes and 13.5 g daily. In a multivariate analysis, independent risk factors for CP were male sex (odds ratio [OR], 2.05), smoking more than 5.5 cigarettes per day (OR, 2.72), and drinking more than 13.5 g/d (OR, 6.35).

CONCLUSIONS

In an Italian population, we confirmed smoking and alcohol as cofactors in the development of CP. This study shows that alcohol intake and smoking habits are 2 of the most important risk factors for the development of CP.

An update on pancreatic pathophysiology (do we have to rewrite pancreatic pathophysiology?)

This review focuses on seven aspects of physiology and pathophysiology of the exocrine pancreas that have been intensively discussed and studied within the past few years: (1) the role of neurohormonal mechanisms like melatonin, leptin, or ghrelin in the stimulation of pancreatic enzyme secretion; (2) the initiation processes of acute pancreatitis, like fusion of zymogen granules with lysosomes leading to intracellular activation of trypsinogen by the lysosomal enzyme cathepsin B, or autoactivation of trypsinogen; (3) the role of genes in the pathogenesis of acute pancreatitis; (4) the role of alcohol and constituents of alcoholic beverages in the pathogenesis of acute pancreatitis; (5) the role of pancreatic hypertension, neuropathy, and central mechanisms for the pathogenesis of pain in chronic pancreatitis; (6) the relation between exocrine pancreatic function and diabetes mellitus; and (7) pathophysiology, diagnosis and treatment of pancreatic steatorrhea.

Pancreas - non-alcoholic constituents and their effects

Alcoholic beverages contain numerous non-alcoholic compounds that could have beneficial or pathological effects. For example, up to now in beer more than 2,000 and in wine more than 1,000 organic and inorganic constituents have been identified. Whereas the role of alcohol (ethanol) in the development of pancreatic diseases - in particular acute and chronic pancreatitis - has been intensively investigated, only little is known about the effects of non-alcoholic compounds in this context. Some of the non-alcoholic constituents have been shown to be biologically active, although discussions of the results in appropriate publications were often not performed with regard to their consumption as a mixture in alcoholic beverages. In this article we provide an overview about 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. 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. However, there is accumulating evidence that non-alcoholic compounds of alcoholic beverages exert different effects on the pancreas. The effects and mechanisms of most single compounds and their combinations are still unknown and thus caution is required in attempting to draw firm conclusions on the effect of non-alcoholic compounds of alcoholic beverages on defining alcoholic etiology of pancreatitis.

Mechanisms of alcoholic pancreatitis

Alcoholic pancreatitis is a major complication of alcohol abuse. The risk of developing pancreatitis increases with increasing doses of alcohol, suggesting that alcohol exerts dose-related toxic effects on the pancreas. However, it is also clear that only a minority of alcoholics develop the disease, indicating that an additional trigger may be required to initiate clinically evident pancreatic injury. It is now well established that alcohol is metabolized by the pancreas via both oxidative and non-oxidative metabolites. Alcohol and its metabolites produce changes in the acinar cells, which may promote premature intracellular digestive enzyme activation thereby predisposing the gland to autodigestive injury. Pancreatic stellate cells (PSCs) are activated directly by alcohol and its metabolites and also by cytokines and growth factors released during alcohol-induced pancreatic necroinflammation. Activated PSCs are the key cells responsible for producing the fibrosis of alcoholic chronic pancreatitis. Efforts to identify clinically relevant factors that may explain the susceptibility of some alcoholics to pancreatitis have been underway for several years. An unequivocal, functionally characterized, association is yet to be identified in clinical studies, although in the experimental setting, endotoxin has been shown to trigger overt pancreatic injury and to promote disease progression in alcohol-fed animals. Thus, while the molecular effects of alcohol on the pancreas have been increasingly clarified in recent years, identification of predisposing or triggering factors remains a challenge.

Can by-products in country-made alcohols induce acute pancreatitis?

OBJECTIVES

We previously reported a high incidence of alcohol-related acute pancreatitis (AP) in Goa, India, where country-made alcoholic products are consumed in addition to the commercially available alcoholic products. We aimed to analyze the composition of these country-made alcoholic products consumed by a population with a high incidence of alcohol-related AP.

METHODS

Three locally distilled alcoholic products (ethanol content, >20%) regularly consumed by patients developing AP, as determined by responses in a patient questionnaire, were selected. Three commercially available products with comparable ethanol content (rum, whiskey, and brandy) were used for comparison. Representative samples were analyzed using gas chromatography/mass spectrometry. Compound assignments used mass spectral searches of the NIST library (2008).

RESULTS

Commercially available rum, whiskey, and brandy used for comparison contained the 2 major constituents, ethanol and water. In addition, the country-made alcoholic products contained a higher level of by-products including long-chain alcohols (eg, butanol, propanol), aldehydes (eg, acetaldehyde), acids (eg, acetic acid), and even traces of methanol.

CONCLUSIONS

Country-made alcoholic products contain many compounds in addition to ethanol. Given the high incidence of alcohol-related AP in the population where these products are consumed, further evaluation of their constituents in relation to the induction of pancreatic damage is warranted.

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.

Alcohol-induced acute pancreatitis: the 'critical mass' concept

The association of alcohol consumption and acute pancreatitis (AP) has been well documented. Extensive research in the field of alcohol-induced AP has allowed scientists to understand the different aspects by which ethanol may alter pancreatic cellular function. However, despite the recognition and understanding of these proposed mechanisms, the basic question that remains unanswered is that although alcohol is consumed the world over, why is it that only some people develop AP? Epidemiologic data indicates a higher frequency of alcohol-induced AP in geographical locations where surrogate/home-brewed alcoholic beverages are freely available. These surrogate/home-brewed alcoholic beverages contain in addition to ethanol, higher alcohols (e.g. propanol and butanol) and other by-products/contaminants (e.g. acids, aldehydes and esters), the potential of which to induce pancreatic damage has been incompletely studied. Mutations in genes that metabolise alcohol as well as those that protect the acinar cells and the extra-acinar milieu from prematurely activated digestive enzymes (e.g. genetic mutations in SPINK1 or PRSS1 genes) have also been noted in these geographical locations. Based on the available epidemiologic, clinical and basic research data available at the present time, we propose a unifying hypothesis presenting for the first time the 'critical mass' concept. We hypothesise that it is the achievement of a 'critical mass' of damaged acinar cells that is required to trigger off the inflammatory cascade leading to a clinically recognised attack of AP. The consequence of a critical mass of damaged acinar cells is the generation of sufficient mediators to result in clinical AP. While the consumption of alcohol does damage acinar cells, the number of damaged acinar cells does not necessarily reach the 'critical mass' with every binge. Co-factors such a high fat or protein meals are required to sensitize the acinar cells by raising the metabolic state to a high level which compromises the viability of the cells. In addition, the existence of genetic mutations and / or the consumption of surrogate alcoholic beverages, by facilitating acinar cell damage, directly or indirectly, potentially hasten the achievement of the 'critical mass', leading to an attack of AP.

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.

Hypertriglyceridemic pancreatitis: presentation and management

Hypertriglyceridemia (HTG) is reported to cause 1-4% of acute pancreatitis (AP) episodes. HTG is also implicated in more than half of gestational pancreatitis cases. Disorders of lipoprotein metabolism are conventionally divided into primary (genetic) and secondary causes, including diabetes, hypothyroidism, and obesity. Serum triglyceride (TG) levels above 1,000 mg/dl are usually considered necessary to ascribe causation for AP. The mechanism for hypertriglyceridemic pancreatitis (HTGP) is postulated to involve hydrolysis of TG by pancreatic lipase and release of free fatty acids that induce free radical damage. Multiple small studies on HTGP management have evaluated the use of insulin, heparin, or both. Many series have also reported use of apheresis to reduce TG levels. Subsequent control of HTG with dietary restrictions, antihyperlipidemic agents, and even regular apheresis has been shown anecdotally in case series to prevent future episodes of AP. However, large multicenter studies are needed to optimize future management guidelines for patients with HTGP.

Fatty acids, alcohol and fatty acid ethyl esters: toxic Ca2+ signal generation and pancreatitis

Pancreatitis, a potentially fatal disease in which the pancreas digests itself as well as its surroundings, is a well recognized complication of hyperlipidemia. Fatty acids have toxic effects on pancreatic acinar cells and these are mediated by large sustained elevations of the cytosolic Ca(2+) concentration. An important component of the effect of fatty acids is due to inhibition of mitochondrial function and subsequent ATP depletion, which reduces the operation of Ca(2+)-activated ATPases in both the endoplasmic reticulum and the plasma membrane. One of the main causes of pancreatitis is alcohol abuse. Whereas the effects of even high alcohol concentrations on isolated pancreatic acinar cells are variable and often small, fatty acid ethyl esters--synthesized by combination of alcohol and fatty acids--consistently evoke major Ca(2+) release from intracellular stores, subsequently opening Ca(2+) entry channels in the plasma membrane. The crucial trigger for pancreatic autodigestion is intracellular trypsin activation. Although there is still uncertainty about the exact molecular mechanism by which this Ca(2+)-dependent process occurs, progress has been made in identifying a subcellular compartment--namely acid post-exocytotic endocytic vacuoles--in which this activation takes place.