Hereditary Pancreatitis Patients Research Articles

Abstract A061: Utility of patient-derived organoids for precision pharmacotyping, phenotypic screens, and modeling of pancreatic disease

Abstract Pancreatic ductal adenocarcinoma (PDA) is projected to soon become the second leading cause of cancer death. Aberrant glycosylation is a hallmark of PDA, but the impact of glycosylation remains vastly understudied in PDA. Additionally, a lack of disease models that recapitulate glycosylation differences observed in human disease has hampered efforts to leverage glycan changes as therapeutic strategies. To address these needs, human patient-derived organoids (PDOs) were employed to address three major questions. First, the use of PDOs in drug screening experiments to characterize therapeutic sensitivity and resistance (i.e. “pharmacotyping”) is a promising precision medicine approach to inform clinical decisions. However, the extent to which different sources of basement membrane extracts (BMEs) in which PDOs are cultured contribute to organoid chemosensitivity profiles is unknown. Mouse and human PDA organoids representing a range of PDA disease stages (early, late, and metastasis) were subjected to a chemotherapy and targeted therapy pharmacotyping panel in different commercial BMEs. Differences in growth kinetics and drug response were analyzed. RNA-seq was performed to determine the impact of BME source on gene expression programs. Results from this work will provide key insights regarding optimal growth of pancreatic PDOs as well as the impact of exogenous factors on pharmacotyping results. Second, elevated serum levels of the glycan CA19-9 are observed in more than 75% of PDA patients. Recent evidence demonstrated that CA19-9 promotes pancreatitis and accelerates pancreatic tumorigenesis in mice, phenotypes that are reversible with the use of CA19-9-targeting antibodies. However, how CA19-9 synthesis is regulated is unknown. We developed organoid high-throughput screens to identify compounds that impact CA19-9 production. Continuing this screen across a library of hPDOs will lay the foundation for the identification of new therapeutic candidates and the understanding of regulators of glycosylation in PDA. Lastly, the pancreatitis is a major risk factor for the development of PDA, with hereditary pancreatitis patients having a 40-55% cumulative risk of developing PDA. However, reliable organoid models of human pancreatitis are lacking. To address this need, we optimized methods to derive PDOs from chronic pancreatitis specimens of genetic and non-genetic etiology. Human chronic pancreatitis organoids underwent multi-omic characterization and credentialing in order to provide the field with more representative models of pancreatitis in humans and a platform to explore early detection strategies and study pancreatic disease progression. Overall, we demonstrate the broad utility of PDOs to identify early detection biomarkers and targetable vulnerabilities in PDA. These models are a renewable resource for the field, enabling elucidation of the molecular underpinnings of the increased susceptibility of chronic pancreatitis to PDA and other fundamental aspects of PDA biology. Citation Format: Jan Lumibao, Shira Okhovat, Kristina Peck, Dannielle Engle. Utility of patient-derived organoids for precision pharmacotyping, phenotypic screens, and modeling of pancreatic disease [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr A061.

214.4: The Genetic Epidemiology of Hereditary Pancreatitis in Australia and Its Effect on Patients of Total Pancreatectomy and Islet Auto Translation (TP-IAT)

Introduction: Hereditary Pancreatitis (HP) is a cause of pancreatitis in childhood leading to lifelong disability and an elevated risk of pancreatic cancer. The clinical and genetic features of HP have not been characterised in Australia. This project aims to understand the effects of HP-associated variants on disease risk and progression, and their pertinence on past and future patients of TP-IAT. Methods: HP patients were identified from existing hospital records. Interviews were administered to collect HP-associated data including pain management, medical prescriptions, interventions, smoking and alcohol history, and overall quality of life. Saliva samples were obtained for whole-exome-sequencing (WES). Genetic data were analysed using standard bioinformatics toolkits for variant discovery and correlation with HP phenotype. This was compared to a control sample of 2,504 patients with adult-onset chronic pancreatitis. Results: A total of 44 HP patients from 10 independent pedigrees were identified. Eighty-four percent of HP cases presented with clinical onset before the age of 10. Eighty-six percent of HP patients reported ongoing opioid use to control pain and 79% of patients reported ongoing moderate to severe pain. The majority (57%) of the HP cohort self-identified as Indigenous Australians and HP was 67 times more prevalent in Indigenous populations than non-Indigenous. Overall, 14/16 individuals underwent TP-IAT exhibited substantial reduction in analgesic requirement. The estimated prevalence of HP in SA was 2.48 per 100,000. HP was ~67 times more prevalent in Indigenous people than non-Indigenous South Australians. The study cohort had a younger age of onset and higher female ratio when compared to 2,504 of control adult-onset CP cases. Conclusion: Our estimated prevalence of HP is higher than previously described and disproportionately affect Indigenous populations. The percentage of HP patients requiring lifelong analgesics is alarming and genetic factors are an important cause of pancreatitis in Australian children. Finally, TP-IAT has been successful as a new therapy for HP management.

Genetic Abnormalities in Pancreatitis: An Update on Diagnosis, Clinical Features, and Treatment.

Several pancreatitis susceptibility genes have been identified to date. A relationship between a mutation in the cationic trypsinogen (protease serine 1, PRSS1) gene and hereditary pancreatitis (HP) was first identified in 1996. Currently, HP has been defined as either two or more individuals within a family exhibiting pancreatitis for two or more generations, or pancreatitis linked to mutation of the PRSS1 gene. In 2000, a mutation in the serine protease inhibitor gene (Kazal type 1: SPINK1) was reported to be related to sporadic pancreatitis of unknown etiology. This paper reviews and summarizes the current published data on the pancreatitis susceptibility genes, mainly PRSS1 and SPINK1 genes, and introduces a diagnostic and therapeutic approach for dealing with patients with these gene mutations. Patients with these genetic predispositions, both children and adults, have often been initially diagnosed with idiopathic acute pancreatitis, in approximately 20–50% of pediatric cases and 28–80% of adult cases. In such patients, where the etiology is unknown, genetic testing, which requires pre-test and post-test genetic counselling, may prove helpful. Patients with chronic pancreatitis (CP) due to SPINK1 gene mutation and HP patients have a potentially high risk of pancreatic exocrine insufficiency, diabetes mellitus, and, of particular importance, pancreatic cancer. Thus, these patients require careful long-term follow-up and management. Specifically, symptomatic CP patients often need endoscopic therapy or surgery, often following a step-up approach beginning with endoscopic therapy and progressing to surgery if necessary, which is similar to the therapeutic approach for patients with CP due to other etiologies. It is important that clinicians are aware of the characteristics of patients with pancreatitis susceptibility genetic abnormalities.

Imaging of genetically-mediated pancreatitis

ObjectivesTo review the imaging of patients with Genetically-Mediated Pancreatitis (GMP), identify common imaging findings in this cohort and assess phenotypical characteristics of specific genotypes. Materials and methodsRetrospective review of the databases of the Irish National Surgical Centre for Pancreatic Cancer (NSCPC) and Cystic Fibrosis (CF) from November 2010 to January 2018. Retrospective imaging and chart review for the patients with positive genetics for GMP. ResultsThe NSCPC database contained 699 patients; the CF database included 352 patients. Of these 1051, 14 were identified as having GMP (age range: 20–65, M:F ratio of 1:1). 14 of 1051 patients from the database had positive genetics for GMP. 10 had imaging to support a diagnosis of hereditary pancreatitis or familial recurrent pancreatitis (1.3%) and 4 had imaging to support a diagnosis of CF-related pancreatitis. Imaging findings were considered in 3 categories, determined by genotype - PRSS1 hereditary pancreatitis, SPINK 1 autosomal recessive pancreatitis and those for CFTR - cystic fibrosis related pancreatitis. Imaging findings in PRSS1 hereditary pancreatitis patients included: pancreatic atrophy, calcification and main pancreatic duct (MPD) dilatation, referred to as the PRSS1 imaging triad. Patients with the SPINK1 gene mutation had less severe imaging manifestations (pancreatic atrophy 33%, MPD dilatation 33%, pancreatic calcification 33%). CFTR patients with imaging findings had pancreatic atrophy (100%). ConclusionGMP should be suspected when the features of ‘chronic pancreatitis’ are seen in young adults with no history of excess alcohol intake. Genetic testing, endocrinology review and long-term imaging follow-up for pancreatic carcinoma are indicated.

Specific Radiological Imaging Findings in Patients With Hereditary Pancreatitis During a Long Follow-up of Disease.

Hereditary pancreatitis (HP) is characterized by recurrent episodes of inflammation of the pancreas. Radiological imaging is used to diagnose HP and to monitor complications. The aim of this study was to describe specific imaging findings in HP. We retrospectively collected data of HP patients with serial imaging and reviewed all radiological imaging studies (transabdominal ultrasonography, computed tomography, and magnetic resonance imaging). We included 15 HP patients, with a mean age of 32.5 years (range, 9-61 years) and mean disease duration of 24.1 years (range, 6-42 years). In total, 152 imaging studies were reviewed. Seventy-three percent of patients had a dilated main pancreatic duct (MPD) (width 3.5-18 mm). The MPD varied in size during disease course, with temporary reduction in diameter after drainage procedures. A severe dilated MPD (>10 mm) often coincided with presence of intraductal calcifications (size, 1-12 mm). In 73% of patients, pancreatic parenchyma atrophy occurred, which did not correlate with presence of exocrine or endocrine insufficiency. In HP, the MPD diameter increases with time, mostly without dilated side branches, and is often accompanied by large intraductal calcifications. The size of the MPD is independent of disease state. Atrophy of pancreatic parenchyma is not correlated with exocrine or endocrine insufficiency.

The clinical course of hereditary pancreatitis in children – A comprehensive analysis of 41 cases

BackgroundAvailable data from adult patients do not reflect natural course of hereditary pancreatitis (HP) in children. To date, no study has assessed the clinical course of HP in children. ObjectiveTo investigate the clinical course of HP in children and compare it to non-HP group with chronic pancreatitis (CP). MethodsA group of 265 children with CP, hospitalized from 1988 to 2014, were enrolled in the study. Medical records of those patients were reviewed for data on presentation, diagnostic findings and treatment. All children were screened for mutations in major pancreatitis-associated genes, i.e. PRSS1, SPINK1, and CFTR. ResultsHP was diagnosed in 41 children (15.5%). Family history was positive in 88% of children with HP. Mutations of PRSS1 gene were found in 80% (33/41) of HP patients. We detected p.R122H, p.R122C, p.N29I, and p.E79K mutation in 34% (14/41), 27% (11/41), 12% (5/41), and 7% (3/41) of HP patients, respectively. Patients with paternal inheritance had first symptoms earlier than those with maternal inheritance (5.9 vs. 9.1 years; P < 0.05). Children with HP showed more severe changes in ERCP then those from non-HP group (2.05 Cambridge grade, vs. 1.6°; P < 0.05). ESWL was performed more frequently in HP group (12.2% vs. 3.1%; P < 0.05). There was no difference in age of disease onset (7.98 vs. 8.9 years; NS), pancreatic duct stenting (46.3% vs. 33%; NS), or number of surgical interventions (12.2% vs. 14.3%; NS) between both groups. ConclusionsChildren with HP reveal significantly more severe clinical presentation of the disease than non-HP patients, despite the same age of onset.

Risk factors for pancreatic cancer: underlying mechanisms and potential targets.

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related deaths among both men and women in the United States and remains essentially without effective therapies. The 5-year survival of patients with pancreatic cancer is a dismal 6% or less. Environmental risk factors such as smoking, diabetes, obesity, and alcoholism play major roles in the promotion of PDAC. However, currently we have limited understanding of how these risk factors promote the disease. The papers presented in this topic illustrate the latest knowledge regarding the mechanisms of pancreatic cancer induction and promotion by major risk factors such as smoking, pancreatitis, alcohol abuse, obesity and diabetes (Kolodecik et al., 2013), and less studied factors such blood group types (Pelzer et al., 2013) and the genetic mutations (Kong et al., 2013; Reznik et al., 2014; Weiss, 2014). Indeed, an inherited predisposition to PDAC is believed to present in familial cancer syndromes such as the Peutz-Jeghers Syndrome, which is associated with germline mutations in the STK11/LKB1 gene, Familial Atypical Multiple Mole Melanoma syndrome, which results due to germline mutations in the p16/CDKN2A gene, Hereditary Breast-Ovarian Cancer syndrome (BRCA1/2 genes), Hereditary Non-polyposis Colorectal Cancer (mismatch repair genes), and Familial Adenomatous Polyposis syndrome (Reznik et al., 2014). Hereditary causes of pancreatitis, such as the autosomal dominant form caused by germline mutations of the cationic trypsinogen gene, PRSS1, have been indirectly linked to PDAC through early onset chronic pancreatitis with an associated 53-fold increased incidence and approximately 40% of hereditary pancreatitis patients noted to develop pancreatic cancer by age 70 (Weiss, 2014). Finally, more patients with blood group A suffer from PDAC whereas blood group O was less frequent in patients with PDAC (Pelzer et al., 2013). Kras mutations remain the most abundant genetic alteration found in pancreatic cancer patients. Kras mutations may lead to reducing power for ROS detoxification, leading to low ROS levels in pancreatic pre-neoplastic cells and in cancer cells. In adult stem cells and cancer stem cells, low ROS levels have been associated with the formation of a proliferation-permissive intracellular environment and with perseverance of self-renewal capacities. Therefore, it is conceivable that low intracellular ROS levels may contribute significantly to oncogenic Kras-mediated PDAC formation (Kong et al., 2013). Specific gene-based, gene-product, and marker-based testing for the early detection of pancreatic cancer are currently being developed, with the potential for these to be useful as potential therapeutic targets as well. Today, the role of stromal cells is highly appreciated for pancreatic cancer development. Immune cell infiltration into the tumor not only fail to contribute to disease eradication but rather due to exhibiting a Th2-type inflammation and immunosuppression is associated with more rapid disease progression, cachexia induction, and reduced survival. Polarization of macrophages toward M2-type correlates with a poor prognosis after surgery in resected patients. High CD163+ and CD204+ cell counts correlate with metastasis and poor prognosis in PDAC patients (Protti and De Monte, 2013; Tan et al., 2014). Src kinase might serve as a critical mechanistic link between inflammation and cancer, mediating and propagating a cycle between immune and tissue cells that can ultimately lead to the development and progression of cancer (Liu et al., 2013). In addition, there is now compelling evidence that pancreatic stellate cells interact not only with cancer cells themselves, but with several other cell types in the stroma (endothelial cells, immune cells, and possibly neuronal cells) to promote cancer progression. Strategies to target the tumor microenvironment cells are proposed (Wilson et al., 2014). The central role of the mammalian target of rapamycin (mTOR) in mediating a crosstalk between the insulin/IGF-1 and GPCR signaling in pancreatic cancer cells is discussed in depth and strategies, including the use of metformin, to target this signaling pathway in PDAC cells are proposed (Rozengurt, 2014). Finally, a comprehensive review of the latest animal models of pancreatic cancer are discussed, proposing novel tools to study the mechanism of pancreatic cancer initiation and promotion by major risk factors.

Pancreatic cancer risk in hereditary pancreatitis

Inflammation is part of the body's immune response in order to remove harmful stimuli—like pathogens, irritants or damaged cells—and start the healing process. Recurrent or chronic inflammation on the other side seems a predisposing factor for carcinogenesis and has been found associated with cancer development. In chronic pancreatitis mutations of the cationic trypsinogen (PRSS1) gene have been identified as risk factors of the disease. Hereditary pancreatitis (HP) is a rare cause of chronic pancreatic inflammation with an early onset, mostly during childhood. HP often starts with recurrent episodes of acute pancreatitis and the clinical phenotype is not very much different from other etiologies of the disease. The long-lasting inflammation however generates a tumor promoting environment and represents a major risk factor for tumor development This review will reflect our knowledge concerning the specific risk of HP patients to develop pancreatic cancer.

Genetic, Epidemiological, and Clinical Aspects of Hereditary Pancreatitis: A Population-Based Cohort Study in Denmark

In a population-based, well-defined group of patients first regarded as having pancreatitis of unknown origin (PUO), we identified, described, and compared the clinical and genetic aspects of patients with hereditary pancreatitis (HP) and with cystic fibrosis transmembrane conductance regulator gene (CFTR) and serine protease inhibitor Kazal type 1 gene (SPINK1) mutations with patients who retained the diagnosis of true idiopathic pancreatitis (tIP) after genetic testing for HP, SPINK1, and CFTR mutations. Patients with PUO were identified in the Danish National Registry of Patients or were referred by clinicians. DNA from blood was analyzed for cationic trypsinogen (PRSS1), SPINK1, and CFTR mutations. Considering the diagnosis of HP, a pedigree was drawn for each patient. A genetic mutation was found in 40% of 122 patients with PUO. After testing first-degree relatives of the 18 initially identified HP patients, 38 HP patients in total were identified, and 28 patients had SPINK1-CFTR mutations. Among HP patients, no p.N29I mutations were found and the p.A16V mutation was more frequent than previously reported, 45 and 32% had exocrine and endocrine insufficiency, respectively, and among tIP patients 9 and 12%, respectively. Pancreatic cancer was diagnosed in 5% of the HP families. The genotype of the Danish population with HP differs from that of previously described cohorts. The occurrence of exocrine and endocrine insufficiency is higher among patients with HP than in patients with SPINK1-CFTR mutations and tIP, and more HP families develop pancreatic cancer. Genetic testing thus helps to predict the prognosis of the pancreatitis.

Hereditary pancreatitis in children: surgical implications with special regard to genetic background

Purpose Hereditary pancreatitis (HP) is the primary etiology of chronic pancreatitis during childhood, progressing through recurrent episodes of acute pancreatitis and finally leading to pancreatic insufficiencies. Hereditary pancreatitis is because of mutations of the cationic trypsinogen (PRSS1) gene. Some other genes, such as SPINK1 or CFTR, have been associated with familial idiopathic chronic pancreatitis. The aim of our study was to clearly define diagnostic and therapeutic strategies for HP patients, through an analysis of our study group and a review of the literature. Methods All children admitted from 1995 to 2007 with a final diagnosis of hereditary pancreatitis were restrospectively included in the study. We analyzed all medical records with special attention given to cases involving genetic screening (PRSS1, SPINK1, and CFTR genes). Results Ten children were included. Eight had HP with PRSS1 mutation, 2 of them without a familial history of chronic pancreatitis. The 2 others patients had SPINK1 mutations. Three HP patients were operated on for acute complications of pancreatitis and are well with a mean follow-up of 5.5 years. No patient had pancreatic insufficiencies or weight loss. Conclusions Hereditary pancreatitis is associated with severe pancreatitis, with a greater risk of developing pancreatic cancer. It must therefore be diagnosed correctly and treated to prevent its considerable complications.

Mortality Rate and Risk Factors in Patients With Hereditary Pancreatitis: Uni- and Multidimensional Analyses

Patients with hereditary pancreatitis (HP) bear a high risk of pancreatic adenocarcinoma, but their life expectancy remains unknown. The objective of the study was to assess whether the high risk of cancer decreases survival. Inclusion criteria were the presence of a PRSS1 mutation with pancreatic symptoms or chronic pancreatitis in at least two first-degree relatives or three second-degree relatives without another cause. Survival rates were assessed according to risk factors. Excess mortality compared with the general French population was calculated (statistical Esteve model) for two periods (20-50 and 50-70 years), according to several risk factors. The cohort comprised 189 patients. PRSS1 mutations were found in 66%. A total of 19 patients died at the median age of 60. In all, 10 deaths were attributable to HP, including 8 to pancreatic adenocarcinoma. Median overall survival for the whole cohort was 74 years (95% confidence interval (CI): 71-79). The presence of R122H mutation, gender, tobacco consumption in patients older than 18 years, and diabetes mellitus were not associated with differences in survival. Only patients with pancreatic cancer had decreased survival (P=0.008). Excess mortality risk compared with the general population was 0.02% between 20 and 50 years, and 0.61% between 50 and 70 years (NS). Gender, R122H mutation, diabetes, and tobacco use were not associated with excess mortality in these two periods. Despite their high risk of cancer, HP patients do not have excess mortality risk compared with the general population, irrespective of gender, tobacco use, or diabetes mellitus. These data should be brought to the patient's attention.

Hereditary pancreatic cancer: A clinical perspective

Pancreatic cancer is an extraordinarily deadly disease and is responsible for over 220,000 deaths worldwide each year. One of the greatest risk factors for developing pancreatic cancer is a positive family history. Hereditary pancreatitis patients have a greatly elevated pancreatic cancer risk and individuals with cystic fibrosis may rarely develop this cancer, but often at very young ages. Various genetically linked cancer syndromes have been associated with pancreatic cancer in mutation-positive family members. Finally, familial pancreatic cancer-defined as families with two or more first-degree relatives who have pancreatic cancer but do not have a known cancer syndrome-is a known entity whose disease-causing mutation remains unidentified. This article describes research to date on hereditary pancreatic cancer, addresses how best clinicians should recognise hereditary forms of pancreatic cancer and explains the emotional burden of discovering a potentially lethal mutation. Many controversies and unanswered questions in hereditary pancreatic cancer remain.

Histopathological Features of Patients with Chronic Pancreatitis due to Mutations in the PRSS1 Gene: Evaluation of BRAF and KRAS2 Mutations

Background/Aims: Hereditary pancreatitis (HP) is a rare cause of chronic pancreatitis (CP; 1%) and more than 25 mutations in the PRSS1 gene have been detected. HP patients with the p.R122H mutation have a 35% lifetime risk of developing pancreatic cancer, but the oncogenetic process remains unknown. We have investigated the histopathological features and frequency of BRAF and KRAS2 mutations in 2 patients with PRSS1 mutations (p.A121T, p.R122H) and patients with CP (n = 11). Methods: Pancreatic tissue was stained with hematoxylin-eosin and examined by light microscopy. Mutational analysis of the BRAF (exon 5, 11) and KRAS2 (exon 1) genes was performed using PCR and direct DNA sequencing. Results: Histopathological features revealed similar results in both patients, pancreata showed strong fibrosis and ducts with signs of distortion, irregular size and noticeable dilatations. We identified one BRAF mutation (p.V600E) in the p.R122H patient and two KRAS2 (p.G12D; p.G12C) mutations in CP controls. Conclusions: Our results sustain the knowledge about the clinical phenotype of patients with PRSS1 mutations who have a high risk of pancreatic cancer. Whether the histopathological picture or the BRAF mutation is specific for patients with PRSS1 mutations or plays a specific role in the tumorigenesis of patients with HP needs to be further evaluated.

International Registries of Families at High Risk of Pancreatic Cancer

Purpose: To describe the need for multinational registries of families at high risk of pancreatic cancer and the issues surrounding identification of such families. Results: A consensus position was published describing surveillance of individuals at high risk of pancreatic cancer. Hereditary pancreatitis patients, people with Peutz-Jeghers syndrome, individuals with CDKN2A or BRCA1/2 mutations with a family history of pancreatic cancer and kindred with multiple pancreatic cancers were considered suitable for research-based screening. Mutations responsible for familial predisposition are mostly unknown, although BRCA2 mutations have been identified in some families and a mutation in the palladin gene has been shown to segregate with pancreatic cancer in one kindred. Specific autosomal dominant inheritance of pancreatic cancer risk seems to involve anticipation; this finding aids identification of families and determination of individual risk. Diabetes mellitus is an early symptom of pancreatic cancer, but recent publications suggest that it may not be a significant predisposing factor; this remains controversial. However, in the context of hereditary pancre- atitis, diabetes probably does predispose to pancreatic cancer as shown in a recent description of French families. Conclusion: Appropriate inclusion of patients within registries of high-risk families provides a framework for secondary screening and research on risk stratification and early tumorigenesis.

The natural history of hereditary pancreatitis: a national series

Background and aims:The prevalence and natural history of hereditary pancreatitis (HP) remain poorly documented. The aims of this study were to assess genetic, epidemiological, clinical and morphological characteristics of HP...

Trypsinogen Copy Number Mutations in Patients With Idiopathic Chronic Pancreatitis

We have recently reported that the triplication of a approximately 605 kilobase segment containing the PRSS1 (encoding cationic trypsinogen) and PRSS2 (encoding anionic trypsinogen) genes causes hereditary pancreatitis. Here we went further to investigate whether this copy number mutation could account for some unidentified French white patients with idiopathic chronic pancreatitis (ICP) or familial chronic pancreatitis (FCP) as well as Indian patients with tropical calcific pancreatitis (TCP). Patients and controls were screened by means of previously described quantitative fluorescent multiplex polymerase chain reaction and/or genotyping of the microsatellite marker rs3222967. The approximately 605 kilobase triplication and a novel duplication (confirmed by fluorescence in situ hybridization) of the trypsinogen locus were detected in 10 and 2 of 202 ICP patients, respectively (age of disease onset, <or=20 years) but were absent in 282 French controls. In addition, the duplication mutation was found in 2 of 1044 ICP patients whose age of disease onset was >20 years. However, the 2 trypsinogen copy number mutations were observed in neither 103 FCP patients nor 268 Indian TCP patients. Our findings revealed the molecular basis of 6% of the young ICP patients and further demonstrated that chronic pancreatitis is a genomic disorder. Our findings also add to the mounting evidence showing that trypsinogen gene mutations do not appear to play an important role in the pathogenesis of TCP in the Indian population. Finally, a dividend of this study is that we have provided convincing evidence to show that all 5 previously described copy number variations involving PRSS1 or/and PRSS2 are artifacts.

Genetic analysis of the glutathione s-transferase genes MGST1, GSTM3, GSTT1, and GSTM1 in patients with hereditary pancreatitis.

Specific mutations in the cationic trypsinogen gene ( PRSS1) are disease-causing in patients with hereditary pancreatitis, but the genetic background still remains mysterious in about 40% of patients with the disease. It has been suggested that oxidative stress contributes to pancreatic damage. The glutathione s-transferases (GSTs) represent major detoxification enzymes that protect cells from oxidative stress. In the present study we tested whether mutations in the MGST1 and GSTM3 genes or common deletions in the GSTT1 and GSTM1 genes are associated with hereditary pancreatitis. We analyzed the entire coding region of MGST1 and GSTM3 in 30 patients that were tested negative for PRSS1 mutations, and we studied 55 controls. For GSTT1 and GSTM1, we investigated 75 hereditary pancreatitis patients who had been tested negative for PRSS1 mutations, 135 hereditary pancreatitis patients with a PRSS1 mutation, and 183 controls. Patients were further subclassified with regard to age of onset of disease as a marker of severity. No mutation was found in the MGST1 gene. In the GSTM3 gene, we detected a homozygous 670G > A polymorphism (V224I) with similar frequencies in patients and controls. We found no difference in the frequencies of the GSTT1 and GSTM1 null genotypes between patients and controls, and we detected no differences in age of onset in patients with or without GSTT1 and GSTM1 deletions. We conclude that genetic alterations in the MGST1, GSTM3, GSTT1, and GSTM1 genes do not play a dominant role in hereditary pancreatitis.

Endoscopic evaluation and management of hereditary pancreatitis

Ever since an association between Trypsinogen mutations and the phenotype of hereditary pancreatitis have been discovered in 1996, this disease variety has been recognized as a pathophysiological challenge and a vexing clinical problem. Affected patients differ from patients with other types of chronic pancreatitis in that they rarely drink alcohol, that the disease process begins early in life and most often affects children and young adults at the time of initial diagnosis, and that there is no removable causative factor and therefore the disease invariably progresses. In this light, we review the available data on endoscopic evaluation and management of affected patients with a particular focus on the early detection of pancreatic cancer, for which the risk in hereditary pancreatitis patients is manifold increased, and on the options for endoscopic treatment of the characteristic complications of the disorder.

Cathepsin B cleavage of the trypsinogen activation peptide.

BackgroundCathepsin B is thought to play a central role in intrapancreatic trypsinogen activation and the onset of pancreatitis. A recent investigation of the cathepsin B mediated activability of wildtype trypsinogen and their mutations N29I, N29T and R122H, which are associated to hereditary pancreatitis, revealed no differences. This action seems to be restricted to the K23-I24 peptide bond, which is the trypsinogen activation bond. Here we investigated the influence of the mutations D22G and K23R of the trypsinogen activation peptide on the cleavability by cathepsin B.MethodsTo investigate the functional impact of the TAP mutations on cathepsin B mediated cleavage of the trypsinogen activating K23-I24 bond, the corresponding peptides pWT, APFDDDDKIVGG; pD22G, APFDDDGKIVGG; and pK23R, APFDDDDRIVGG were digested with cathepsin B for 30 min at pH 3.8 and 5.0, and the fragments were analysed by high-performance liquid chromatography.ResultsWithout cathepsin B, less than 1 % of the peptides were hydrolysed. After a 30-minute digestion with cathepsin B at pH 5, 96% of pWT, 48% of pK23R, but only 2.4% of pD22G were hydrolysed. At pH 3.8, the cathepsin B cleavage of pWT and pK23R was less than at pH 5, whereas the cleavage of pD22G was completely inhibitedConclusionsCathepsin B mediated trypsinogen activation seems not to be a crucial pathogenic step in hereditary pancreatitis patients with the trypsinogen mutations D22G and K23R.

The N34S mutation of SPINK1 (PSTI) is associated with a familial pattern of idiopathic chronic pancreatitis but does not cause the disease.

Mutations in the PRSS1 gene explain most occurrences of hereditary pancreatitis (HP) but many HP families have no PRSS1 mutation. Recently, an association between the mutation N34S in the pancreatic secretory trypsin inhibitor (SPINK1 or PSTI) gene and idiopathic chronic pancreatitis (ICP) was reported. It is unclear whether the N34S mutation is a cause of pancreatitis per se, whether it modifies the disease, or whether it is a marker of the disease. A total of 327 individuals from 217 families affected by pancreatitis were tested: 152 from families with HP, 108 from families with ICP, and 67 with alcohol related CP (ACP). Seven patients with ICP had a family history of pancreatitis but no evidence of autosomal dominant disease (f-ICP) compared with 87 patients with true ICP (t-ICP). Two hundred controls were also tested for the N34S mutation. The findings were related to clinical outcome. The N34S mutation was carried by five controls (2.5%; allele frequency 1.25%), 11/87 (13%) t-ICP patients (p=0.0013 v controls), and 6/7 (86%) affected (p<0.0001 v controls) and 1/9 (11%) unaffected f-ICP cases. N34S was found in 4/108 affected HP patients (p=0.724 v controls), in 3/27 (11%) with wild-type and in 1/81 (1%) with mutant PRSS1, and 4/67 ACP patients (all p>0.05 v controls). The presence of the N34S mutation was not associated with early disease onset or disease severity. The prevalence of the N34S mutation was increased in patients with ICP and was greatest in f-ICP cases. Segregation of the N34S mutation in families with pancreatitis is unexplained and points to a complex association between N34S and another putative pancreatitis related gene.