Early-onset Chronic Pancreatitis Research Articles

Genetic and functional analysis of chymotrypsin-like protease (CTRL) in chronic pancreatitis

BackgroundGenetic predisposition is crucial in the pathogenesis of early-onset chronic pancreatitis (CP). So far, several genetic alterations have been identified as risk factors, predominantly in genes encoding digestive enzymes. However, many early-onset CP cases have no identified underlying cause. Chymotrypsins are a family of serine proteases that can cleave trypsinogen and lead to its degradation. Because genetic alterations in the chymotrypsins CTRC, CTRB1, and CTRB2 are associated with CP, we genetically and functionally investigated chymotrypsin-like protease (CTRL) as a potential risk factor. MethodsWe screened 1005 non-alcoholic CP patients and 1594 controls for CTRL variants by exome sequencing. We performed Western blots and activity assays to analyse secretion and proteolytic activity. We measured BiP mRNA expression to investigate the potential impact of identified alterations on endoplasmic reticulum (ER) stress. ResultsWe identified 13 heterozygous non-synonymous CTRL variants: five exclusively in patients and three only in controls. Functionality was unchanged in 6/13 variants. Four alterations showed normal secretion but reduced (p.G20S, p.G56S, p.G61S) or abolished (p.S208F) activity. Another three variants (p.C201Y, p.G215R and p.C220G) were not secreted and already showed reduced or no activity intracellularly. However, intracellular retention did not lead to ER stress. ConclusionWe identified several CTRL variants, some showing potent effects on protease function and secretion. We observed these effects in variants found in patients and controls, and CTRL loss-of-function variants were not significantly more common in patients than controls. Therefore, CTRL is unlikely to play a relevant role in the development of CP.

Identification of protease-sensitive but not misfolding PNLIP variants in familial and hereditary pancreatitis

Mutations in the PNLIP gene have recently been implicated in chronic pancreatitis. Several PNLIP missense variants have been reported to cause protein misfolding and endoplasmic reticulum stress although genetic evidence supporting their association with chronic pancreatitis is currently lacking. Protease-sensitive PNLIP missense variants have also been associated with early-onset chronic pancreatitis although the underlying pathological mechanism remains enigmatic. Herein, we provide new evidence to support the association of protease-sensitive PNLIP variants (but not misfolding PNLIP variants) with pancreatitis. Specifically, we identified protease-sensitive PNLIP variants in 5 of 373 probands (1.3%) with a positive family history of pancreatitis. The protease-sensitive variants, p.F300L and p.I265R, were found to segregate with the disease in three families, including one exhibiting a classical autosomal dominant inheritance pattern. Consistent with previous findings, protease-sensitive variant-positive patients were often characterized by early-onset disease and invariably experienced recurrent acute pancreatitis, although none has so far developed chronic pancreatitis.

Variants in the pancreatic CUB and zona pellucida-like domains 1 (CUZD1) gene in early-onset chronic pancreatitis - A possible new susceptibility gene

ObjectiveNon-alcoholic chronic pancreatitis (NACP) frequently develops in the setting of genetic susceptibility associated with alterations in genes that are highly expressed in the pancreas. However, the genetic basis of NACP remains unresolved in a significant number of patients warranting a search for further risk genes. DesignWe analyzed CUZD1, which encodes the CUB and zona pellucida-like domains 1 protein that is found in high levels in pancreatic acinar cells. We sequenced the coding region in 1163 European patients and 2018 European controls. In addition, we analyzed 297 patients and 1070 controls from Japan. We analyzed secretion of wild-type and mutant CUZD1 from transfected cells using Western blotting. ResultsIn the European cohort, we detected 30 non-synonymous variants. Using different prediction tools (SIFT, CADD, PROVEAN, PredictSNP) or the combination of these tools, we found accumulation of predicted deleterious variants in patients (p-value range 0.002–0.013; OR range 3.1–5.2). No association was found in the Japanese cohort, in which 13 non-synonymous variants were detected. Functional studies revealed >50% reduced secretion of 7 variants, however, these variants were not significantly enriched in European CP patients. ConclusionOur data indicate that CUZD1 might be a novel susceptibility gene for NACP. How these variants predispose to pancreatitis remains to be elucidated.

Loss of function TRPV6 variants are associated with chronic pancreatitis in nonalcoholic early-onset Polish and German patients

PurposeLoss of function variants of the transient receptor potential cation channel, subfamily V, member 6 (TRPV6) have been recently associated with chronic pancreatitis (CP) in Japanese, German and French patients. Here, we investigated the association of TRPV6 variants with CP in independent European cohorts of early-onset CP patients from Poland and Germany. Patients and methodsWe enrolled 152 pediatric CP patients (median age 8.6 yrs) with no history of alcohol/smoking abuse and 472 controls from Poland as well as 157 nonalcoholic young CP patients (median age 20 yrs) and 750 controls from Germany. Coding regions of TRPV6 were screened by Sanger and next generation sequencing. Selected, potentially pathogenic TRPV6 variants were expressed in HEK293T cells and TRPV6 activity was analyzed using ratiometric Ca2+ measurements. ResultsOverall, we identified 10 novel (3 nonsense and 7 missenses) TRPV6 variants in CP patients. TRPV6 p.V239SfsX53 nonsense variant and the variants showing significant decrease in intracellular Ca2+ concentration in HEK293T cells (p.R174X, p.L576R, p.R342Q), were significantly overrepresented in Polish patients as compared to controls (6/152, 3.9% vs. 0/358, 0%; P = 0,0007). Nonsense TRPV6 variants predicted as loss of function (p.V239SfsX53 and p.R624X) were also significantly overrepresented in German patients (3/157; 2.0% vs 0/750; 0%, P = 0.005). ConclusionsWe showed that TRPV6 loss of function variants are associated with elevated CP risk in early-onset Polish and German patients confirming that TRPV6 is a novel CP susceptibility gene.

Clinical Course of Chronic Pancreatitis During Pregnancy and its Effect on Maternal and Fetal Outcomes.

There are limited data on the effect of chronic pancreatitis (CP) on pregnancy outcomes and vice versa. Our aim was to evaluate the clinical trajectory of CP during pregnancy and its effect on pregnancy outcomes. All female patients of child-bearing age (≥15 years) diagnosed with CP were studied from January 2004 to July 2019. The change in frequency of painful episodes was assessed before, during, and after pregnancy. Maternal and fetal outcomes were compared between pregnant women (early onset) and women presenting with CP after completion of all pregnancies (late onset). Of 187 women with CP, pregnancy outcomes and clinical course were assessed in 99 patients. The frequency of painful exacerbations was significantly lower during pregnancy compared with prepregnancy and postpregnancy periods (P < 0.001). The median pain score decreased significantly to 0 (0-2) during pregnancy from 3 (0-6) before conception and increased to 4 (0-8) after pregnancy (P = 0.002). Women with early onset CP (n = 57) had their first child later and had fewer pregnancies compared with those with late onset CP (n = 42). There was no difference in maternal outcomes such as gestational diabetes, hypertension, and preterm delivery, and fetal outcomes such as abortion, low birth weight, and still birth between the groups. There was no reported congenital anomaly. Younger patients with CP had later and fewer pregnancies, but there was no increased risk of adverse maternal and fetal outcomes. The clinical course of CP was usually benign during pregnancy with decreased frequency and severity of pain.

Variants That Affect Function of Calcium Channel TRPV6 Are Associated With Early-Onset Chronic Pancreatitis

Changes in pancreatic calcium levels affect secretion and might be involved in development of chronic pancreatitis (CP). We investigated the association of CP with the transient receptor potential cation channel subfamily V member 6 gene (TRPV6), which encodes a Ca2+-selective ion channel, in an international cohort of patients and in mice. We performed whole-exome DNA sequencing from a patient with idiopathic CP and from his parents, who did not have CP. We validated our findings by sequencing DNA from 300 patients with CP (not associated with alcohol consumption) and 1070 persons from the general population in Japan (control individuals). In replication studies, we sequenced DNA from patients with early-onset CP (20 years or younger) not associated with alcohol consumption from France (n= 470) and Germany (n= 410). We expressed TRPV6 variants in HEK293 cells and measured their activity using Ca2+ imaging assays. CP was induced by repeated injections of cerulein in TRPV6mut/mut mice. We identified the variants c.629C>T (p.A210V) and c.970G>A (p.D324N) in TRPV6 in the index patient. Variants that affected function of the TRPV6 product were found in 13 of 300 patients (4.3%) and 1 of 1070 control individuals (0.1%) from Japan (odds ratio [OR], 48.4; 95% confidence interval [CI], 6.3-371.7; P= 2.4× 10-8). Twelve of 124 patients (9.7%) with early-onset CP had such variants. In the replication set from Europe, 18 patients with CP (2.0%) carried variants that affected the function of the TRPV6 product compared with 0 control individuals (P= 6.2× 10-8). Variants that did not affect the function of the TRPV6 product (p.I223T and p.D324N) were overrepresented in Japanese patients vs control individuals (OR, 10.9; 95% CI, 4.5-25.9; P= 7.4× 10-9 for p.I223T and P= .01 for p.D324N), whereas the p.L299Q was overrepresented in European patients vs control individuals (OR, 3.0; 95% CI, 1.9-4.8; P= 1.2× 10-5). TRPV6mut/mut mice given cerulein developed more severe pancreatitis than control mice, as shown by increased levels of pancreatic enzymes, histologic alterations, and pancreatic fibrosis. We found that patients with early-onset CP not associated with alcohol consumption carry variants in TRPV6 that affect the function of its product, perhaps by altering Ca2+ balance in pancreatic cells. TRPV6 regulates Ca2+ homeostasis and pancreatic inflammation.

Identification of novel and rare recurrent genetic variants in early onset chronic pancreatitis by whole exome sequencing

Acute pancreatitis is accompanied by acinar cell damage releasing potential toll-like receptor 3 (TLR3) ligands. So far, TLR3 is known as a pattern recognition receptor in the immune signaling cascade triggering a type I interferon response. In addition, TLR3 signaling contributes to programmed cell death through the activation of caspase 8. However, the functional role of TLR3 and its downstream toll-like receptor adaptor molecule 1 (TICAM1) in the inflamed pancreas is unknown.To uncover the role of TLR3 signaling in acute pancreatitis, we induced a cerulein-mediated pancreatitis in Tlr3 and Ticam1 knockout (KO) mice and in wildtype animals. The exocrine damage was determined by blood serum analysis and histological examination. Immunohistochemistry, gene expression and immunoblot analysis were conducted to study TLR3 function.After the induction of an acute pancreatitis, wildtype mice showed a high endosomal TLR3 expression in acinar cells. In comparison to wildtype and Ticam1 KO mice, Tlr3 KO mice exhibited the highest severity of pancreatitis with an increased NF-κB activation and elevated expression of the pro-inflammatory cytokines Il6 and Tnf, although the amount of infiltrating immune cells was unaffected. Additionally, we detected a strong elevation of acinar cell necrosis and reduced levels of cleaved caspase 8 in Tlr3 and Ticam1 KO mice.TLR3 and its downstream adaptor TICAM1 are important mediators of acinar cell damage in acute pancreatitis. They possess a critical role in programmed cell death and our data suggest that TLR3 signaling controls the onset and severity of acute pancreatitis.

Protease-Sensitive Pancreatic Lipase Variants Are Associated With Early Onset Chronic Pancreatitis.

Premature activation of the digestive protease trypsin within the pancreatic parenchyma is a critical factor in the pathogenesis of pancreatitis. Alterations in genes that affect intrapancreatic trypsin activity are associated with chronic pancreatitis (CP). Recently, carboxyl ester lipase emerged as a trypsin-independent risk gene. Here, we evaluated pancreatic lipase (PNLIP) as a potential novel susceptibility gene for CP. We analyzed all 13 PNLIP exons in 429 nonalcoholic patients with CP and 600 control subjects from Germany, in 632 patients and 957 controls from France, and in 223 patients and 1,070 controls from Japan by DNA sequencing. Additionally, we analyzed selected exons in further 545 patients with CP and 1,849 controls originating from Germany, United States, and India. We assessed the cellular secretion, lipase activity, and proteolytic stability of recombinant PNLIP variants. In the German discovery cohort, 8/429 (1.9%) patients and 2/600 (0.3%) controls carried a PNLIP missense variant (P = 0.02, odds ratio [OR] = 5.7, 95% confidence interval [CI] = 1.1-38.9). Variants detected in patients were prone to proteolytic degradation by trypsin and chymotrypsin. In the French replication cohort, protease-sensitive variants were also enriched in patients with early-onset CP (5/632 [0.8%]) vs controls (1/957 [0.1%]) (P = 0.04, OR = 7.6, 95% CI = 0.9-172.9). In contrast, we detected no protease-sensitive variants in the non-European populations. In the combined European data, protease-sensitive variants were found in 13/1,163 cases (1.1%) and in 3/3,000 controls (0.1%) (OR = 11.3, 95% CI = 3.0-49.9, P < 0.0001). Our data indicate that protease-sensitive PNLIP variants are novel genetic risk factors for the development of CP.

Variants in pancreatic carboxypeptidase genes CPA2 and CPB1 are not associated with chronic pancreatitis.

Genetic alterations in the carboxypeptidase A1 gene (CPA1) are associated with early onset chronic pancreatitis (CP). Besides CPA1, there are two other human pancreatic carboxypeptidases (CPA2 and CPB1). Here we examined whether CPA2 and CPB1 alterations are associated with CP in Japan and Germany. All exons and flanking introns of CPA2 and CPB1 were sequenced in 477 Japanese patients with CP (234 alcoholic, 243 nonalcoholic) and in 497 German patients with nonalcoholic CP by targeted next-generation sequencing and/or Sanger sequencing. Secretion and enzymatic activity of CPA2 and CPB1 variants were determined after transfection into HEK 293T cells. We identified six nonsynonymous CPA2 variants (p.V67I, p.G166R, p.D168E, p.D173H, p.R237W, and p.G388S), eight nonsynonymous CPB1 alterations (p.S65G, p.N120S, p.D172E, p.R195H, p.D208N, p.F232L, p.A317V, and p.D364Y), and one splice-site variant (c.687+1G>T) in CPB1. Functional analysis revealed essentially complete loss of function in CPA2 variants p.R237W and p.G388S and CPB1 variants p.R110H and p.D364Y. None of the CPA2 or CPB1 variants, including those resulting in a marked loss of function, were overrepresented in patients with CP. In conclusion, CPA2 and CPB1 variants are not associated with CP.

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.

Variants in CPA1 are strongly associated with early onset chronic pancreatitis

Chronic pancreatitis is an inflammatory disorder of the pancreas. We analyzed CPA1, encoding carboxypeptidase A1, in subjects with nonalcoholic chronic pancreatitis (cases) and controls in a German discovery set and three replication sets. Functionally impaired variants were present in 29/944 (3.1%) German cases and 5/3,938 (0.1%) controls (odds ratio (OR) = 24.9, P = 1.5 × 10(-16)). The association was strongest in subjects aged ≤ 10 years (9.7%; OR = 84.0, P = 4.1 × 10(-24)). In the replication sets, defective CPA1 variants were present in 8/600 (1.3%) cases and 9/2,432 (0.4%) controls from Europe (P = 0.01), 5/230 (2.2%) cases and 0/264 controls from India (P = 0.02) and 5/247 (2.0%) cases and 0/341 controls from Japan (P = 0.013). The mechanism by which CPA1 variants confer increased pancreatitis risk may involve misfolding-induced endoplasmic reticulum stress rather than elevated trypsin activity, as is seen with other genetic risk factors for this disease.

Overexpression of Interleukin-1β in the Murine Pancreas Results in Chronic Pancreatitis

Chronic pancreatitis is a significant cause of morbidity and a known risk factor for pancreatic adenocarcinoma. Interleukin-1beta is a proinflammatory cytokine involved in pancreatic inflammation. We sought to determine whether targeted overexpression of interleukin-1beta in the pancreas could elicit localized inflammatory responses and chronic pancreatitis. We created a transgenic mouse model (elastase sshIL-1beta) in which the rat elastase promoter drives the expression of human interleukin-1beta. Mice were followed up for up to 2 years. Pancreata of elastase sshIL-1beta mice were analyzed for chronic pancreatitis-associated histologic and molecular changes. To study the potential effect of p53 mutation in chronic pancreatitis, elastase sshIL-1beta mice were crossed with p53(R172H) mice. Three transgenic lines were generated, and in each line the pancreas was atrophic and occasionally showed dilation of pancreatic and biliary ducts secondary to proximal fibrotic stenosis. Pancreatic histology showed typical features of chronic pancreatitis. There was evidence for increased acinar proliferation and apoptosis, along with prominent expression of tumor necrosis factor-alpha; chemokine (C-X-C motif) ligand 1; stromal cell-derived factor 1; transforming growth factor-beta1; matrix metallopeptidase 2, 7, and 9; inhibitor of metalloproteinase 1; and cyclooxygenase 2. The severity of the lesions correlated well with the level of human interleukin-1beta expression. Older mice displayed acinar-ductal metaplasia but did not develop mouse pancreatic intraepithelial neoplasia or tumors. Elastase sshIL-1beta*p53(R172H/+) mice had increased frequency of tubular complexes, some of which were acinar-ductal metaplasia. Overexpression of interleukin-1beta in the murine pancreas induces chronic pancreatitis. Elastase sshIL-1beta mice consistently develop severe chronic pancreatitis and constitute a promising model for studying chronic pancreatitis and its relationship with pancreatic adenocarcinoma.

Hereditary chronic pancreatitis

Hereditary chronic pancreatitis (HCP) is a very rare form of early onset chronic pancreatitis. With the exception of the young age at diagnosis and a slower progression, the clinical course, morphological features and laboratory findings of HCP do not differ from those of patients with alcoholic chronic pancreatitis. As well, diagnostic criteria and treatment of HCP resemble that of chronic pancreatitis of other causes. The clinical presentation is highly variable and includes chronic abdominal pain, impairment of endocrine and exocrine pancreatic function, nausea and vomiting, maldigestion, diabetes, pseudocysts, bile duct and duodenal obstruction, and rarely pancreatic cancer. Fortunately, most patients have a mild disease. Mutations in the PRSS1 gene, encoding cationic trypsinogen, play a causative role in chronic pancreatitis. It has been shown that the PRSS1 mutations increase autocatalytic conversion of trypsinogen to active trypsin, and thus probably cause premature, intrapancreatic trypsinogen activation disturbing the intrapancreatic balance of proteases and their inhibitors. Other genes, such as the anionic trypsinogen (PRSS2), the serine protease inhibitor, Kazal type 1 (SPINK1) and the cystic fibrosis transmembrane conductance regulator (CFTR) have been found to be associated with chronic pancreatitis (idiopathic and hereditary) as well. Genetic testing should only be performed in carefully selected patients by direct DNA sequencing and antenatal diagnosis should not be encouraged. Treatment focuses on enzyme and nutritional supplementation, pain management, pancreatic diabetes, and local organ complications, such as pseudocysts, bile duct or duodenal obstruction. The disease course and prognosis of patients with HCP is unpredictable. Pancreatic cancer risk is elevated. Therefore, HCP patients should strongly avoid environmental risk factors for pancreatic cancer.

Mutational screening of patients with nonalcoholic chronic pancreatitis: identification of further trypsinogen variants

OBJECTIVES: Mutations of the cationic trypsinogen (CT) and the serine protease inhibitor, Kazal type 1 (SPINK 1) are associated with chronic pancreatitis. After mutational screening of a cohort of patients with nonalcoholic chronic pancreatitis, we report three novel variants of the trypsinogen molecule and the clinical characteristics of the carriers. METHODS: The coding region of the exon 2 and 3 of the CT gene of 523 patients with chronic nonalcoholic pancreatitis (108 patients with suspected hereditary pancreatitis (HP) and 415 patients with “idiopathic” pancreatitis [IP]) and 82 controls was analyzed after polymerase chain reaction amplification. Clinical characteristics were obtained by questioning the patients and their relatives and physicians. HP was suspected when two members of a family had chronic pancreatitis. A restriction digestion was used to analyze the N34S mutation SPINK 1. RESULTS: The mutation R122H of the cationic trypsinogen was found in 21 index patients, N29I in six index patients, and A16V and D22G in one index patient, all from HP families. The N34S mutation of SPINK 1 was found in two index patients with a family history of HP. In three patients, the novel point mutations L104P, R116C, and C139F of the cationic trypsinogen were found. A clear autosomally dominant inheritance of chronic pancreatitis was not present in these families. In 75 index patients from HP families (69.4%), no mutation could be found. The SPINK 1-mutation N34S was detected in only one patient carrying a CT mutation, and was found in 68 (16.4%) of patients with IP. CONCLUSIONS: The R122H and N29I mutations of CT are the most common disease-associated mutations in HP; the N34S mutation of SPINK 1 is the most frequent genetic risk factor associated with IP. The CT gene carries several variations that could be associated with chronic pancreatitis. To avoid overestimating the pathogenetic impact of novel trypsinogen variants, a detailed clinical characterization of all patients with early onset chronic pancreatitis is mandatory.

Relevance of Variants in Serum Antiproteinases for the Course of Chronic Pancreatitis

Background: Mutations of the pancreatic serine protease inhibitor, Kazal type 1 (SPINK1), the cationic trypsinogen (PRSS1) and the cystic fibrosis transmembrane conductance regulator (CFTR) were reported to be genetic risk factors of chronic pancreatitis (CP). The aim of this study was to determine the role of genetic variants of the main serum antiproteinases alpha-1-antitrypsin (AAT) and alpha-2-macroglobulin (A2M) for the course of chronic pancreatitis. Methods: 124 patients with non-alcoholic chronic pancreatitis (with PRSS1 or SPINK1 mutations or idiopathic pancreatitis) and 64 healthy controls were investigated for the AAT mutations PiS and PiZ, and the PiM determining variants R101H, V213A, E376D. In 101 subjects, thèbait region' of A2M was sequenced. A pentanucleotide deletion in the bait region of A2M was analysed in 147 chronic pancreatitis (CP) patients and 87 controls. Results: The lowest prevalences of V213A and E376D were found in PRSS1 patients, whereas an increased rate of these mutations was present in the SPINK1 group, and the highest prevalence was found in patients with idiopathic pancreatitis. The prevalence of PiM variants was higher in patients with early onset CP than in late onset ( P < 0.05 for E376D). The coding region of the bait region of A2M was of wild type in all investigated subjects. The A2M pentanucleotide deletion showed a homogenous distribution in patients and controls. Conclusions: Our study suggests a moderating, but not predominant, role of AAT variants in the course of chronic non-alcoholic pancreatitis.