Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030305 (pancreatitis)
 16,014 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Due to autodigestion the activity of dissolved trypsin successively decreases. Autolysis leads to proteolytic cleavages of some arginyl and lysyl peptide bonds of the trypsin structure. Three important autolysis sites have been reported for bovine trypsin: Lys61-Ser62, Arg117-Val118 and Lys145-Ser146. Out of these three sites only the first two exist in rat trypsin, an enzyme that has been the target of protein engineering for more than ten years. In this work Lys61 and Arg117 were replaced by Asn via site directed mutagenesis to transform the corresponding peptide bonds to trypsin resistant ones. Kinetic parameters of K61N, R117N and the double mutant K61N/R117N are practically identical with those of the wild-type enzyme. By contrast, the rate of autolysis of each singly-substituted species is substantially slower than with the parent trypsin. In particular, the double mutant shows dramatically increased stability against autolysis and decreased sensitivity to Ca2+. The process of autolysis has been followed by N-terminal sequence determination. We propose a model to explain why these two positions play a key role in autolysis and how Ca2+ can influence this process. In addition, our in vitro results strongly support the recently proposed model of human hereditary pancreatitis.
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PMID:Two mutations in rat trypsin confer resistance against autolysis. 947 79

Hereditary pancreatitis is an autosomal dominant disorder with incomplete penetrance. It is characterised by recurring episodes of severe abdominal pain and often presents in childhood. Recently, a mutation in the cationic trypsinogen gene was identified in this disease. Previously, only one mutation at residue 117 of the trypsinogen gene has been found in the five separate hereditary pancreatitis families, four from the USA and one from Italy. Alteration of the Arg117 site is believed to disrupt a fail-safe mechanism for the inactivation of trypsin, leading to autodigestion of the pancreas under certain conditions. Molecular analysis of the trypsinogen gene was carried out on a hereditary pancreatitis family from the UK. The same G to A mutation at residue 117 was identified in this family, suggesting that this is a common mutation in hereditary pancreatitis.
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PMID:Evidence for a common mutation in hereditary pancreatitis. 971 98

The mortality rate in acute pancreatitis (AP) is significantly lower in patients hospitalized directly at the intensive care unit than in patients admitted to hospital in 2 weeks after the assessment of diagnosis, prophylactic administration of low-molecular protease inhibitor reduces the occurrence of post ERCP pancreatitis a well a coincident complications. Despite rational considerations concerning the significance of pryphylactic administration of antibodies (ATB) in severe AP, there still not enough convincing data which could be recommended a standard therapy. One of the concepts of causal therapy of AP. Suggest that inhibition of exocrine pancreatic enzymatic secretion reduces autodigestion of the gland (setting the gland at rest). The reports on success of secretin-inhibiting substances a glucagon, calcitonin, atropine and somatostatin require confirmation in randomized or accurately defined comparable groups. The initial studies on the therapeutic significance of lexipanphate-antagonist of platelet activating factor (PAF) in acute pancreatitis is promising. A long-term lavage had reduced the mortality.
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PMID:[Therapy of acute pancreatitis]. 972 66

For over a century it has been assumed that acute pancreatitis represents an autodigestion of the pancreas by its own, physiologically inactive proteases. Whether, how and where digestive proteases are being activated in the pancreas has remained the topic of much controversy and speculation. We review a number of recent studies that have been undertaken to elucidate the mechanisms and identify the initial subcellular localization of this process. These studies suggest that a premature and intrapancreatic protease activation does, indeed, occur early in pancreatitis and can be experimentally induced in vivo and in vitro. Activation begins within minutes of the induction of pancreatitis and is initially confined to cytoplasmic vacuoles at the apical pole of acinar cells. From here trypsin activity as well as its activation peptide are transferred to the cytosol of acinar cells where autodigestion may begin.
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PMID:[Role of protease activation in pathophysiology of acute pancreatitis]. 993 52

Acute pancreatitis may follow a mild or a severe course. Whereas mild or edematous pancreatitis is a self-limiting disease with a low complication rate and low death rate, morbidity and mortality in severe or necrotizing pancreatitis are still unacceptably high. The major problem is the lack of a specific drug, especially in the early phase of the disease, to interfere with the systemic inflammatory response syndrome and to limit or prevent complications of the disease. Although the initiating pathophysiological process is not known, the destruction of the gland ('autodigestion') by digestive enzymes may be responsible for disease progression. Inhibition of pancreatic activity, which reduces exocrine secretion and further prevents the release and activation of enzymes, was therefore suggested as a specific treatment concept. The results of clinical investigations using somatostatin or its analogue are controversial, since all these trials had low statistical power. In a recent multicenter randomized controlled study with a large number of patients (n = 302) (and an adequate level of disease severity), no benefit of octreotide on progression or outcome was found. Chronic pancreatitis is characterized by an irreversible destruction of the exocrine and endocrine pancreatic parenchyma leading to maldigestion and diabetes. Pain, which may be caused by increased ductal pressure, is one of the most dominant symptoms in chronic pancreatitis. However, no beneficial effects on pain with pancreatic exocrine secretion-inhibiting drugs have been demonstrated. Treatment of other complications of the disease (pseudocyst formation, fistula and pancreatic ascites), with somatostatin or octreotide has given conflicting results. However, in a prophylactic clinical setting (e.g. elective pancreatic surgery) the inhibition of exocrine pancreatic secretion reduces complications.
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PMID:The role of octreotide and somatostatin in acute and chronic pancreatitis. 1020 28

Alcohol consumption is the most important etiological factor of chronic pancreatitis (around 70%). Smoking, ethnic-racial predispositions, diets high and low in fat and high in protein may also contribute to the development of chronic pancreatitis. Non-alcoholic chronic pancreatitis of unknown cause makes up 10% to 30% of patients with chronic pancreatitis. Two subgroups have been reported: juvenile (about 25 years) and senile (up 65 years). Tropical pancreatitis has been observed in children and young men in many African and Asian countries. This disease develops because of fat and protein deficiency or nutritional deficiency in general, also due to cyanogenes present in cassava. Hereditary chronic pancreatitis is a rare disease connected with autosomal transmissions. Dr Whitcomb reported, that hereditary chronic pancreatitis developed because of trypsines mutation. Mutant "hypertrypsin" is not inactivated by enzymes; this way it leads to pancreas autodigestion. Obstructive chronic pancreatitis is caused by longterm pancreatic ducts obstruction. In many rare causes leading to chronic pancreatitis among other are: hypercalcaemia, hyperlipoproteinemia, some drugs and pancreatitis associated with autoimmune disorders. Newest information about etiology and pathogenesis of chronic pancreatitis is yielded by recent immunohistochemical research. This research shows increasing irregular improper antigens expression of class I and/or class II MHC in pancreas as well as the role of Transforming Growth Factor Alpha in chronic pancreatitis development. This illness is still a puzzling problem.
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PMID:[Contemporary opinions on the etiology of chronic pancreatitis]. 1050 45

In healthy subjects, the 3 known pancreatic trypsinogens, which are endopeptidases belonging to the chymotrypsin superfamily, are activated by enterokinase and partial autoactivation in the duodenum. The premature activation of trypsinogen in the pancreatic interstitium, with the subsequent activation of other pancreatic zymogens, is believed to lead to the autodigestion of the gland, this being the first event in acute pancreatitis. The mechanisms that lead to trypsinogen, activation in acute pancreatitis are largely unknown. However, ischemia, hypercalcemia and the activation of cathepsin B (by cholecystokinin) are thought to be of importance. The easiest and most reliable way to assess trypsinogen activation is the measurement of the activation peptide, TAP, in urine, plasma, pancreatic tissue or ascitic fluid. In the animal model of acute pancreatitis, TAP in ascites and pancreatic tissue has been shown to correlate with the presence and extent of necroses. It has proven to be a good marker for the severity of pancreatitis and is a useful marker in examining the pathophysiology and possible treatment modalities in the animal model of acute pancreatitis. Studies on TAP in human acute pancreatitis were most commonly focused on urinary TAP. Within a 48-hour time frame after the onset of the disease, TAP was a good predictor of the severity of acute pancreatitis. The main advantage over other markers, such as CRP, is that TAP is the earliest marker of necrosis to be increased. Also, increased levels of TAP in ascitic fluid were shown to correlate well with pancreatic necroses. In our experience, plasma TAP was found to have a "diagnostic window" within the first 3 days predicting pancreatic necroses. Positive TAP gave a very good positive prediction and a high specificity towards the development of pancreatic necroses, but did not differ between necrotizing pancreatitis with systemic complications or uncomplicated necrotizing pancreatitis. We therefore think that plasma TAP is a very good marker for local complication in acute pancreatitis and its routine measurements may help to identify patients at a high risk within the first days of the disease.
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PMID:Mechanism and role of trypsinogen activation in acute pancreatitis. 1057 41

The exocrine pancreas synthesizes and secretes large amounts of digestive proteases as inactive precursor zymogens. Under physiological conditions a variety of cellular defense mechanisms protect the pancreatic acinar cell against a premature and intracellular activation of these zymogens. When these defenses fail, pancreatic autodigestion is initiated and acute pancreatitis can develop. A number of experimental observations suggest that extra- as well as intracellular calcium concentrations play an important part in the initiation of pancreatic protease activation, but the intracellular signaling events that regulate this process are unknown. Using a model system in which we used pancreatic acini (freshly prepared functional units of living acinar cells), we were able to simulate the conditions found during experimental pancreatitis in rodents. By means of a cell permeant fluorescent trypsin substrate we could demonstrate in these acini that premature protease activation is initiated at the apical acinar cell pole and occurs only in the presence of secretagogue concentrations that exceed those required for a maximum secretory response. By combining this technique with fluorescence ratio imaging for the Ca(2+)-sensitive dye fura-2, we could further show that this protease activation is highly dependent on the spatial as well as the temporal distribution of the corresponding Ca(2+) release from stores within the same subcellular compartment and that it is not propagated to neighboring acinar cells.
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PMID:The role of intracellular calcium signaling in premature protease activation and the onset of pancreatitis. 1088 Mar 74

Hereditary pancreatitis is an unusual form of acute and chronic pancreatitis with a familial predisposition. Recently, the gene mutations causing most cases of hereditary pancreatitis have been identified in the cationic trypsinogen gene. The known mutations are trypsinogen R117H and N211. These may predispose to acute pancreatitis by eliminating one of the fail-safe mechanisms used by the pancreas to eliminate prematurely activated trypsin. Accumulation of active trypsin mutants are hypothesized to initiate a digestive enzyme activation cascade in the pancreatic acinar cells leading to autodigestion, an intense inflammatory response, and acute pancreatitis. The observation that these patients also develop typical chronic pancreatitis and may later develop pancreatic cancer provides strong evidence that these conditions are linked. Knowledge of the pathophysiological conditions leading to acute and chronic pancreatitis and the development of a transgenic mouse expressing the mutant human trypsinogen genes will provide directions and tools necessary for the effective treatment or prevention of this human disease.
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PMID:Hereditary pancreatitis: new insights, new directions. 1103 Jun 5

The recent genetic discoveries in CP support the hypothesis that inappropriate intrapancreatic activation of zymogens by trypsin results in autodigestion and pancreatitis. Two different protective mechanisms prevent activation of the pancreatic digestive enzyme cascade. First, SPINK1 inhibits up to 20% of potential trypsin activity and, second, trypsin itself activates trypsin-like enzymes readily degrading trypsinogen and other zymogens. Pancreatitis may therefore be the result of an imbalance between proteases and their inhibitors within the pancreatic parenchyma. The discovery of PRSS1 mutations in families with CP was the first breakthrough in the understanding of the underlying genetic mechanisms. Enhanced trypsinogen activation may be the common initiating step in pancreatitis caused by these mutations. The discovery of SPINK1 mutations underlines the importance of the protease inhibitor system in the pathogenesis of CP. Thus, gain-of-function in the cationic trypsinogen resulting in an enhanced autoactivation, or loss-of-function mutations in SPINK1 leading to decreased inhibitory capacity, may similarly disturb the delicate intrapancreatic balance of proteases and their inhibitors. The recent findings of SPINK1, CFTR, and PRSS1 mutations in CP patients without a family history have challenged the concept of idiopathic CP as a non-genetic disorder and the differentiation between HP and ICP. There is a clear mode of autosomal dominant inheritance for some mutations (R122H, N291, possibly MIT), whereas the inheritance pattern (autosomal recessive, complex, or modifying) of other mutations (A16V, N34S) is controverted or unknown. The lack of mutations in the above-mentioned genes in many patients suggests that CP may also be caused by genetic alterations in yet unidentified genes. Evaluation of CP patients without an obvious predisposing factor, e.g. alcohol abuse, should include genetic testing even in the absence of a family history of pancreatitis. Finally, identification of further disease-causing genes will create a better understanding of pathogenesis and may help to develop specific preventive and therapeutic strategies.
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PMID:Genetic aspects of chronic pancreatitis: insights into aetiopathogenesis and clinical implications. 1177 91


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