Alcohol-induced chronic pancreatitis in rats after temporary occlusion of biliopancreatic ducts with Ethibloc

Natural Recovery by the Liver and Other Organs after Chronic Alcohol Use

Chronic, heavy alcohol consumption disrupts normal organ function and causes structural damage in virtually every tissue of the body. Current diagnostic terminology states that a person who drinks alcohol excessively has alcohol use disorder. The liver is especially susceptible to alcohol-induced damage. This review summarizes and describes the effects of chronic alcohol use not only on the liver, but also on other selected organs and systems affected by continual heavy drinking—including the gastrointestinal tract, pancreas, heart, and bone. Most significantly, the recovery process after cessation of alcohol consumption (abstinence) is explored. Depending on the organ and whether there is relapse, functional recovery is possible. Even after years of heavy alcohol use, the liver has a remarkable regenerative capacity and, following alcohol removal, can recover a significant portion of its original mass and function. Other organs show recovery after abstinence as well. Data on studies of both heavy alcohol use among humans and animal models of chronic ethanol feeding are discussed. This review describes how (or whether) each organ/tissue metabolizes ethanol, as metabolism influences the organ’s degree of injury. Damage sustained by the organ/tissue is reviewed, and evidence for recovery during abstinence is presented.

Alcoholic pancreatitis: Lessons from the liver

The association between alcohol consumption and pancreatitis has been recognized for over 100 years. Despite the fact that this association is well recognized, the mechanisms by which alcohol abuse leads to pancreatic tissue damage are not entirely clear. Alcohol abuse is the major factor associated with pancreatitis in the Western world. Interestingly, although most cases of chronic pancreatitis and many cases of acute pancreatitis are associated with alcohol abuse, only a small percentage of individuals who abuse alcohol develop this disease. This situation is reminiscent of the association between alcohol abuse and the incidence of alcoholic liver disease. The liver and the pancreas are developmentally very closely related. Even though these two organs are quite different, they exhibit a number of general structural and functional similarities. Furthermore, the diseases mediated by alcohol abuse in these organs exhibit some striking similarities. The diseases in both organs are characterized by parenchymal cell damage, activation of stellate cells, aberrant wound healing, and fibrosis. Because of the similarities between the liver and the pancreas, and the alcohol-associated diseases of these organs, we may be able to apply much of the knowledge that we have gained regarding the effects of alcohol on the liver to the pancreas.

Gene-environment factors that contribute to alcoholic pancreatitis in humans

Alcohol-associated acute and chronic pancreatitis occur in a minority of alcohol users, suggesting that most drinkers are protected from pancreatic diseases while a subset is susceptible. Ongoing studies suggest that the pathophysiology is complex and can involve multiple genetic and environmental pathways and stochastic events. Both rat models and human genetic epidemiology studies have been used to understand susceptibility and modifying factors in humans. Rat studies suggest that different types of altered pancreatic physiology occur depending on dose, they occur rapidly and that alcohol changes the immune response to recurrent pancreatic injury. Human studies suggest that PRSS1 and SPINK1 mutation increase the pancreas' susceptibility to alcohol-associated pancreatitis, and that tobacco smoking, and some factors, affect disease progression.

Animal models and their results in gastrointestinal alcohol research

Alcohol-induced diseases of the gastrointestinal tract play an important role in clinical gastroenterology. However, the precise pathophysiological mechanisms are still largely unknown. Alcohol research depends essentially on animal models due to the fact that controlled experimental studies of ethanol-induced diseases in humans are unethical. Animal models have already been successfully applied to disclose and analyze molecular mechanisms in alcohol-induced diseases, partially by using knockout technology. Because of a lack of transferability of some animal models to the human condition, results have to be interpreted cautiously. For some alcohol-related diseases like chronic alcoholic pancreatitis, the ideal animal model does not yet exist. Here we provide an overview of the most commonly used animal models in gastrointestinal alcohol research. We will also briefly discuss the findings based on animal models as well as the current concepts of pathophysiological mechanisms involved in acute and chronic alcoholic damage of the esophagus, stomach, small and large intestine, pancreas and liver.

Theories, mechanisms, and models of alcoholic chronic pancreatitis

Alcoholic chronic pancreatitis is a severe, disabling, chronic inflammatory condition of the pancreas that is seen in fewer than 5% of alcoholics. The severity and unpredictability of this condition has lead to several theories on the mechanism causing chronic pancreatitis based on careful clinical observation. Hypothetical mechanisms were applied to various animal models. Finally, following multiple lines of evidence, there is a convergence of thought and development of some new models that are quite instructive. Taken together, chronic alcohol consumption by rats results in multiple effects on the pancreas that increase the risk of acute pancreatitis, including ongoing acinar cell injury that lowers the threshold for hyperstimulation-induced acute pancreatitis, neurohormonal injury, and adaptation that results in acinar cell hyperstimulation, increased susceptibility to viral mediated acute pancreatitis, and possibly other factors. After acute pancreatitis initiates the inflammatory process, the chronic inflammation and fibrosis of alcoholic chronic pancreatitis are driven by diet, the acinar cell stress response to continued alcohol that may be potentiated by toxic alcohol metabolites, hypoxia, hyperstimulation, and partial duct obstruction; plus the effects of proinflammatory immunocytes and cytokines; and by stellate cell-mediated fibrosis driven by anti-inflammatory cytokines, alcohol, and alcohol metabolites. The factors determining which alcoholic will develop alcoholic chronic pancreatitis likely involve genetic factors, dietary factors, and susceptibility to pancreatic injury through several mechanisms ranging from trauma to gallstones to viruses.

Animal models in gastrointestinal alcohol research-a short appraisal of the different models and their results

Alcohol-related diseases of the gastrointestinal tract play an important role in clinical gastroenterology. However, the mechanisms and pathophysiology underlying the effects of ethanol on the organs of the digestive tract are not yet completely understood. Animal models represent an essential tool for investigating alcohol-related diseases because they give researchers the opportunity to use methods that cannot be used in humans, such as knockout technology. However, there is still a need for new animal models resembling the human condition, since for some alcohol-related diseases such as chronic alcoholic pancreatitis, the ideal animal model does not yet exist. In this chapter, we provide an overview of the most commonly used animal models in gastrointestinal alcohol research. We will also briefly discuss the current concepts of the pathophysiological mechanisms involved in acute and chronic alcoholic damage of the oesophagus, stomach, small and large intestine, pancreas and liver.

Nociception in persistent pancreatitis in rats: effects of morphine and neuropeptide alterations

BACKGROUND

Most animal models of pancreatitis are short-lived or very invasive. A noninvasive animal model of pancreatitis developed in highly inbred rats by Merkord with symptoms persisting for 3 weeks was adopted in the current study to test its validity as a model of visceral pain in commercially available rats.

METHODS

The persistent pancreatitis model was established by tail vein injection of dibutyltin dichloride. Animals were given 10% alcohol in their drinking water to enhance the pancreatitis attack. Blood serum pancreatic enzymes and nociceptive state were monitored for 3 weeks after dibutyltin dichloride or vehicle. Behavioral testing included reflexive withdrawal to mechanical and thermal stimulation of the abdominal area. The effect of morphine on nociceptive behaviors was tested. Histologic analysis of the pancreas and immunohistochemical analysis of substance P and calcitonin gene-related peptide in the spinal cord are included in the study.

RESULTS

Compared with naïve and vehicle-only injected control groups, rats receiving dibutyltin dichloride demonstrated an increase in withdrawal events after von Frey stimulation and decreased withdrawal latency after thermal stimulation, signaling a sensitized nociceptive state through 7 days. These pain-related measures were abrogated by morphine. Blood serum concentrations of amylase and lipase as well as tissue inflammatory changes and substance P were also significantly elevated during this same time period.

CONCLUSIONS

These results indicate that animals with the dibutyltin dichloride-induced experimental pancreatitis expressed serum, histologic, and behavioral characteristics similar in duration to those present during acute attacks experienced by patients with chronic pancreatitis. These findings and responsivity to morphine suggest the utility of this model developed in a commercially available strain of rats for study of persistent visceral pain.

Animal models in alcoholic pancreatitis--what can we learn?

Although the majority of patients with chronic pancreatitis present a history of excessive alcohol consumption, the pathophysiology underlying chronic alcoholic pancreatitis remains poorly defined. Since experimental animal models represent helpful tools in understanding human disease, numerous laboratory studies have been designed to study the effects of alcohol on the pancreas. In the present article we summarize the existing animal models that have been used to investigate the effects of acute and chronic alcohol application on the development of morphological alterations and pancreatic injury. Despite considerable experimental effort, acute or chronic ethanol feeding alone failed to cause acute or chronic pancreatitis in animals. However, ethanol-feeding and the combination with other procedures has demonstrated several mechanisms that play a role in ethanol-induced pancreatic injury. Among these ethanol-induced alterations and mechanisms are the reduction of pancreatic blood-flow and microcirculation, damaging effects of ethanol metabolites, increased pancreatic acinar cell expression of digestive and lysosomal enzymes, increased glandular enzyme content, additional nutritional factors, pancreatic duct obstruction, and limitations of pancreatic regeneration. Although no satisfactory animal model for alcoholic pancreatitis has been developed, these animal models have provided insights in several factors that predispose the pancreas to development of pancreatic injury and contribute to alcoholic pancreatitis.

Pathogenesis and the natural course of chronic pancreatitis

This article gives an overview about current thinking in pathogenesis and natural course /therapy in chronic pancreatitis. Alcohol consumption is still the most relevant factor in the development of chronic pancreatitis, a disease with enormous personal and social impact, shortening life expectancy up to 10-20 yrs. Pathogenesis of chronic pancreatitis has to be considered for different symptoms. Particularly pain, the most bothering symptom, is most likely due to a combination of hypertension in the organ and parenchymal alterations. Pathogenesis of pancreatic head enlargement remains largely elusive. In particular it is not known what triggers growth factors to step into action. Most other symptoms like common bile duct stenosis or portal hypertension are secondary to this enlargement of the head of the pancreas.

Long-term follow-up of patients with chronic pancreatitis in Italy

BACKGROUND

We investigated the epidemiologic, clinical, and radiologic aspects of a mixed medicosurgical series of chronic pancreatitis patients observed at the University of Verona Centre for the Study of Pancreatic Diseases over the period 1971-1995.

METHODS

Even though the pathogenesis of chronic pancreatitis has yet to be clarified and the classification is still debatable, the patients were subdivided in accordance with the Marseilles-Rome classification into those with alcoholic, obstructive, familial, and idiopathic forms of the disease. A total of 715 patients were analysed with a median follow-up period of 10 years (range, 1-25 years).

RESULTS AND CONCLUSIONS

At the end of follow-up the dropout rate amounted to 7.1% (51 patients), and 176 patients (24.6%) had died. Data are reported about the type of chronic pancreatitis, sex, and age distribution at the onset of the disease, drinking and smoking habits before onset and during follow-up, and incidence of calcifications, pain, diabetes, steatorrhoea, and pseudocysts. Surgical aspects, survival curves, and causes of death are also analysed, and the most frequent concomitant diseases in chronic pancreatitis sufferers are discussed.

Lithostathine messenger RNA expression in different types of chronic pancreatitis

Lithostathine may play a physiological role in preventing the precipitation of excess calcium in the pancreatic juice. The hypothesis has been advanced that in chronic calcifying pancreatitis the abnormal biosynthesis of lithostathine might be the original defect to which genetic proneness to the disease may be ascribed. The aim of the present work was to study lithostathine messenger RNA expression in the pancreas of patients with different types of pancreatitis. Lithostathine and chymotrypsinogen mRNA were determined in surgical specimens obtained from the pancreases of the following subjects: (a) 13 patients with chronic alcoholic pancreatitis (84.6% calcified); (b) 4 patients with chronic hereditary pancreatitis (all calcified); (c) 6 patients with chronic obstructive pancreatitis (4 calcified); and (d) 27 subjects suffering from pancreatic cancer. Significantly lower concentrations of both mRNAs were found in the pancreases of chronic pancreatitis patients than in non-cancerous tissue from pancreatic cancer subjects. However, about 70% of the pancreatic cancer subjects showed lithostathine and chymotrypsinogen mRNA levels comparable to those of chronic pancreatitis patients. These results indicate that the decrease in the level of mRNA is not specific to lithostathine and it is unrelated to the presence of pancreatic stones.

Mechanisms of action of alcohol administration on the trophic effect of soybean trypsin inhibitor and cholecystokinin octapeptide in rat

Influence of alcohol administration on the trophic effect of cholecystokinin-octapeptide and soybean trypsin inhibitor administration was examined in male Wistar rats. Two x 4 mL of 20% alcohol given intragastrically during 2 wk did not significantly influence pancreatic weight, DNA, protein, trypsin, chymotrypsin, amylase, lipase, or trypsin inhibitor contents of the pancreas. It diminished the hypertrophy but not the hyperplasia seen after CCK-8 treatment, and eliminated the hyperplasia, as well as the hypertrophy provoked by SBTI administration. Secretory studies and CCK measurements demonstrated decreased CCK release in response to SBTI stimulation after 3-d alcohol administration. The results indicate that alcohol inhibits the enzyme synthesis of the CCK stimulated dividing and/or newly formed acinar cells and the endogenous CCK release.