Hereditary pancreatitis: epidemiology, molecules, mutations, and models

Expression of a cold-adapted fish trypsin in Pichia pastoris

Trypsin is a highly valuable protease that has many industrial and biomedical applications. The growing demand for non-animal sources of the enzyme and for trypsins with special properties has driven the interest to clone and express this protease in microorganisms. Reports about expression of recombinant trypsins show wide differences in the degree of success and are contained mainly in patent applications, which disregard the difficulties associated with the developments. Although the yeast Pichia pastoris appears to be the microbial host with the greatest potential for the production of trypsin, it has shown problems when expressing cold-adapted fish trypsins (CAFTs). CAFTs are considered of immense value for their comparative advantage over other trypsins in a number of food-processing and biotechnological applications. Thus, to investigate potential obstacles related to the production of CAFTs in P. pastoris, the cunner fish trypsin (CFT) was cloned in different Pichia expression vectors. The vectors were constructed targeting both internal and secreted expression and keeping the CFT native signal peptide. Western-blotting analysis confirmed the expression with evident differences for each construct, observing a major effect of the leader peptide sequence on the expression patterns. Immobilized nickel affinity chromatography yielded a partially purified recombinant CFT, which exhibited trypsin-specific activity after activation with bovine enterokinase.

Hereditary pancreatitis: clinical characteristics and diagnostic criteria in Japan

BACKGROUND/AIM

Hereditary pancreatitis (HP) is the strongest known risk factor for pancreatic cancer. The aim of the present study is to establish diagnostic criteria for HP to predict and identify high-risk groups for pancreatic cancer.

METHOD

We collected clinical data for 210 patients with recurrent acute or chronic pancreatitis, and examined mutations of the cationic trypsinogen (CT) gene in 57 patients with a family history of pancreatitis or with early-onset idiopathic recurrent acute or chronic pancreatitis (40 years of age or younger). DNA was extracted from peripheral blood leukocytes, and exons 2 and 3 of the CT gene were individually amplified by polymerase chain reaction (PCR) and sequenced.

RESULTS

Of these 57 patients in whom mutations of the CT gene were examined, the R122H (20 patients) and N29I (5 patients) mutations in the CT gene were observed in 25 patients (43.9%). From the analysis of clinical records and the CT gene of these patients, we proposed the following adaptations to the diagnostic criteria for HP: (1) at least one of the affected members in a family has no known etiological factors, (2) we deleted the definition of "different generation", but included the upper limit of the age of onset of pancreatitis in the case of siblings (at least 1 of the patients in a family <40 years of age). According to these criteria, all patients with the CT gene mutations in the present study could be classified as having HP, with the exception of 2 sporadic cases with the R122H and N29I mutations, respectively. Based on these findings, we revised the criteria for the diagnosis of HP; (1) recurrent acute or chronic pancreatitis with R122H or N29I mutation of the CT gene, or (2) recurrent acute or chronic pancreatitis with a family history of 2 or more affected patients, irrespective of generation, with at least 1 of the patients having no known etiological factors, and in case of siblings only, the onset of the disease in at least 1 of the patients is under age 40 years.

CONCLUSION

The revised criteria in the present study are appropriate and of clinical usefulness to diagnose patients with HP even in cases without the genetic testing. However, if and when more genes are detected, it will be important to reexamine the mutation-negative patients now classified as HP based on our proposed criteria.

Recurrent Acute Pancreatitis

Patients with recurrent acute pancreatitis should be treated with the same supportive and symptom-oriented measures as those with acute pancreatitis. The need for specific treatment depends on the cause of the pancreatitis. Patients should discontinue alcohol use, putative causative medications, and exposure to toxins or helminths in endemic areas. Metabolic abnormalities need to be corrected, and appropriate treatment should be initiated for associated infections, autoimmune diseases, vasculitis, and hypercoagulable states. For patients with gallstone pancreatitis, endoscopic retrograde cholangiopancreatography is indicated if biliary obstruction persists or if cholangitis is present. Elective cholecystectomy may be performed in appropriate patients; otherwise, consider biliary sphincterotomy and ursodeoxycholic acid for prevention of recurrent attacks. Transpapillary stenting or sphincterotomy of the minor papilla benefits some patients with pancreas divisum and no other explanation for recurrent pancreatitis. Surgical sphincteroplasty is reserved for those failing endoscopic treatment. Biliary sphincterotomy benefits more than 50% of patients with sphincter of Oddi dysfunction and recurrent acute pancreatitis. Some authors advocate pancreatic sphincter manometry and sphincterotomy for persistent pancreatic segment hypertension in patients who have recurrent pancreatitis after biliary sphincterotomy. In patients with pancreatic duct strictures, transpapillary stent placement serves as a short-term measure; most patients ultimately require surgery.

Genetic testing in acute and chronic pancreatitis

Hereditary pancreatitis (HP) is clinically indistinguishable from pancreatitis with other causes. Patients with HP have an increased chance of developing pancreatitis. Mutations in the cationic trypsinogen gene appear to cause most HP, although there is evidence for mild genetic heterogeneity with defects in other genes. Trypsin stabilization and protection from autolysis appear to play a central role in the pathogenesis of pancreatitis. The role of mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) as well as the pancreatic secretory trypsin inhibitor (PSTI) in patients with pancreatitis is intriguing but as yet incompletely understood. Genetic testing may help to identify and manage patients with HP. Healthcare professionals should understand the elements necessary for obtaining informed consent for patients undergoing these tests, the limits in interpreting test results, and the psychosocial issues that may arise from genetic testing.

Recurrent acute pancreatitis: an algorithmic approach to identification and elimination of inciting factors

Recurrent acute pancreatitis represents a challenging clinical problem associated with significant morbidity, impairment in quality of life, and expense. If unchecked, recurrent episodes of acute pancreatitis may lead to chronic pancreatitis. In this work we have combined the opinion of experts in pancreatology and an extensive review of the literature to develop a logical algorithm that facilitates the stepwise identification and elimination of inciting factors using current technology. The approach taken in recurrent acute pancreatitis is clearly dependent on adequate and appropriate evaluation and treatment of the patient with an initial episode of acute pancreatitis. Future advances in the treatment of these patients will almost certainly depend on improved imaging modalities, prospective clinical trials assessing the efficacy of endoscopic and surgical intervention, a better understanding of mutations and pathophysiologic mechanisms responsible for recurrent acute pancreatitis, and the development of novel, effective preventive and therapeutic strategies.