Chronic pancreatitis: challenges and advances in pathogenesis, genetics, diagnosis, and therapy

Comprehensive screening for PRSS1, SPINK1, CFTR, CTRC and CLDN2 gene mutations in Chinese paediatric patients with idiopathic chronic pancreatitis: a cohort study

OBJECTIVE

Genetic alterations may contribute to chronic pancreatitis (CP) in Chinese young patients. This study was designed to investigate mutations of cationic trypsinogen (PRSS1), pancreatic secretory trypsin inhibitor or serine protease inhibitor Kazal type 1 (SPINK1), cystic fibrosis transmembrane conductance regulator (CFTR), chymotrypsin C (CTRC) and CLDN2 genes and the copy number variations (CNVs) of PRSS1 and asses associations with the development of idiopathic CP (ICP) in Chinese children.

DESIGN

Retrospective.

SETTING

A single center.

PARTICIPANTS

75 ICP Chinese children (40 boys and 35 girls).

PRIMARY AND SECONDARY OUTCOME MEASURES

Mutations of PRSS1, SPINK1, CFTR, CTRC and CLDN2 genes and CNVs.

RESULTS

7 patients had heterozygous mutations in PRSS1, that is, N29I (n=1), R122H or R122C (n=6). The CNVs of PRSS1 in five patients had abnormal copies (1 copy (n=4), five copies (n=1)). 43 patients had IVS3+2T>C (rs148954387) (10 homozygous and 33 heterozygous) in SPINK1. None of the PRSS1 mutation patients carried a SPINK1 mutation. Frequency of PRSS1 and SPINK1 mutations was 9.3% and 57.3%, respectively, with an overall frequency of 66.6% (50/75). In addition, one patient had a novel deletion of CFTR (GCTTCCTA from c.500 to c.508 leading to the shortened polypeptide molecule via a stop codon). Another patient had a novel missense in CLDN2 exon 2 (c.592A>C mutation). Clinically, patients with SPINK1 mutations had a higher rate of pancreatic duct stones, pancreatic pseudocyst and pancreatic calcification than those without SPINK1 mutations (p<0.05).

CONCLUSIONS

SPINK1 mutations were more commonly associated with Chinese children with ICP. SPINK1 IVS3+2T>C mutation may play an important role in the pathogenesis of Chinese paediatric ICP. However, further study is needed to confirm and to investigate the role of these genes in the development of Chinese ICP.

New insights into the pathogenesis of pancreatitis

PURPOSE OF REVIEW

In this article, we review important advances in our understanding of the mechanisms of pancreatitis.

RECENT FINDINGS

The relative contributions of intrapancreatic trypsinogen activation and nuclear factor kappa B (NFκB) activation, the two major early independent cellular events in pancreatitis, have been investigated using novel genetic models. Trypsinogen activation has traditionally held the spotlight for many decades as the central pathogenic event of pancreatitis. However, recent experimental evidence points to the role of trypsin activation in early acinar cell damage but not in the inflammatory response of acute pancreatitis, which was shown to be induced by NFκB activation. Further, chronic pancreatitis developed independently of trypsinogen activation in the caerulein model. Sustained NFκB activation, but not persistent intra-acinar expression of active trypsin, was shown to result in chronic pancreatitis. Calcineurin-NFAT (nuclear factor of activated T-cells) signaling was shown to mediate downstream effects of pathologic rise in intracellular calcium. Interleukin-6 was identified as a key cytokine mediating pancreatitis-associated lung injury.

SUMMARY

Recent advances challenge the long-believed trypsin-centered understanding of pancreatitis. It is becoming increasingly clear that activation of intense inflammatory signaling mechanisms in acinar cells is crucial to the pathogenesis of pancreatitis, which may explain the strong systemic inflammatory response in pancreatitis.

Rapid progression of a splenic aneurysm due to segmental arterial mediolysis: a rare cause of acute pancreatitis

BACKGROUND

The etiology of acute pancreatitis can be manifold, beside the usual causes. We are reporting an unusual cause that triggered acute pancreatitis.

PATIENT & RESULTS

A 50 year-old male experienced attacks of acute pancreatitis (abdominal pain and elevated amylase and lipase) during sexual arousal. Serial imaging showed a rapidly-progressing, partly-thrombosed splenic artery aneurysm, with local compression of the pancreas. After angiographic coiling, the attacks subsided. Further angiography revealed additional aneurysms consistent with segmental arterial mediolysis at other sites of the body. Molecular analysis regarding Ehlers-Danlos-syndrome and genetic factors for pancreatitis, autoantibodies and Syphilis serology was negative.

CONCLUSIONS

Acute pancreatitis was triggered by a transient rise in blood pressure during sexual stimulation, which caused rapid progression of a splenic artery aneurysm as part of systemic segmental arterial mediolysis.

Chronic pancreatitis: a path to pancreatic cancer

Chronic pancreatitis predisposes to pancreatic cancer development and both diseases share a common etiology. A central role has been proposed for the digestive enzyme-secreting acinar cell that can undergo ductal metaplasia in the inflammatory environment of pancreatitis. This metaplastic change is now a recognised precursor of pancreatic cancer. Inflammatory molecules also foster tumour growth through autocrine and paracrine effects in the epithelium and the stroma. These insights have raised new opportunities such as the manipulation of inflammation as a preventive and/or therapeutic strategy for pancreatic cancer. Finally, we address the need for an in-depth study of the pancreatic acinar cells.

A conservative assessment of the major genetic causes of idiopathic chronic pancreatitis: data from a comprehensive analysis of PRSS1, SPINK1, CTRC and CFTR genes in 253 young French patients

Idiopathic chronic pancreatitis (ICP) has traditionally been defined as chronic pancreatitis in the absence of any obvious precipitating factors (e.g. alcohol abuse) and family history of the disease. Studies over the past 15 years have revealed that ICP has a highly complex genetic architecture involving multiple gene loci. Here, we have attempted to provide a conservative assessment of the major genetic causes of ICP in a sample of 253 young French ICP patients. For the first time, conventional types of mutation (comprising coding sequence variants and variants at intron/exon boundaries) and gross genomic rearrangements were screened for in all four major pancreatitis genes, PRSS1, SPINK1, CTRC and CFTR. For the purposes of the study, synonymous, intronic and 5'- or 3'-untranslated region variants were excluded from the analysis except where there was persuasive evidence of functional consequences. The remaining sequence variants/genotypes were classified into causative, contributory or neutral categories by consideration of (i) their allele frequencies in patient and normal control populations, (ii) their presumed or experimentally confirmed functional effects, (iii) the relative importance of their associated genes in the pathogenesis of chronic pancreatitis and (iv) gene-gene interactions wherever applicable. Adoption of this strategy allowed us to assess the pathogenic relevance of specific variants/genotypes to their respective carriers to an unprecedented degree. The genetic cause of ICP could be assigned in 23.7% of individuals in the study group. A strong genetic susceptibility factor was also present in an additional 24.5% of cases. Taken together, up to 48.2% of the studied ICP patients were found to display evidence of a genetic basis for their pancreatitis. Whereas these particular proportions may not be extrapolable to all ICP patients, the approach employed should serve as a useful framework for acquiring a better understanding of the role of genetic factors in causing this oligogenic disease.

Pancreatitis activates pancreatic apelin-APJ axis in mice

Pancreatitis is classified into acute pancreatitis (AP) and chronic pancreatitis (CP). Apelin, a small regulatory peptide, is the endogenous ligand for the APJ receptor. Apelin and APJ are expressed in the pancreas. The aims of this study were to examine whether apelin influences the inflammatory and fibrosis responses to pancreatitis in mice and to identify mechanisms behind apelin's activities. Supramaximal cerulein induction of AP or CP caused significant (P < 0.05) elevations in pancreatic apelin and APJ expression. Levels declined during the recovery phases. In apelin gene-knockout mice with pancreatitis, pancreatic neutrophil invasion and myeloperoxidase activity were enhanced significantly, and apelin treatment suppressed both. Apelin exposure reduced CP-induced elevations of extracellular matrix-associated proteins. Apelin inhibited PDGF-simulated connective tissue growth factor production and proliferation of pancreatic stellate cells (PSCs). Serum granulocyte colony-stimulating factor and keratinocyte cytokine levels were higher in apelin gene-knockout than wild-type mice with pancreatitis. Apelin reduced AP- and CP-induced elevations in pancreatic NF-κB activation. Together, these findings imply that the pancreatic apelin-APJ system functions to curb the inflammatory and fibrosis responses during pancreatitis. Furthermore, findings suggest that apelin reduces inflammation and fibrosis by reducing neutrophil recruitment and PSC activity. Inhibition of neutrophil invasion may be mediated by reduced keratinocyte cytokine and granulocyte colony-stimulating factor secretion. Apelin-induced reductions in PSC proliferation and connective tissue growth factor production are putative mechanisms underlying apelin's inhibition of extracellular matrix production. The apelin-associated changes in NF-κB binding may be linked to apelin's regulation of pancreatic inflammatory and fibrosis responses during pancreatitis.

Differences in the degree of cerulein-induced chronic pancreatitis in C57BL/6 mouse substrains lead to new insights in identification of potential risk factors in the development of chronic pancreatitis

A frequently used experimental model of chronic pancreatitis (CP) recapitulating human disease is repeated injection of cerulein into mice. C57BL/6 is the most commonly used inbred mouse strain for biomedical research, but widespread demand has led to generation of several substrains with subtly different phenotypes. In this study, two common substrains, C57BL/6J and C57BL/6NHsd, exhibited different degrees of CP, with C57BL/6J being more susceptible to repetitive cerulein-induced CP as assessed by pancreatic atrophy, pancreatic morphological changes, and fibrosis. We hypothesized that the deficiency of nicotinamide nucleotide transhydrogenase (NNT) protein in C57BL/6J is responsible for the more severe C57BL/6J phenotype but the parameters of CP in NNT-expressing transgenic mice generated on a C57BL6/J background do not differ with those of wild-type C57BL/6J. The highly similar genetic backgrounds but different CP phenotypes of these two substrains presents a unique opportunity to discover genes important in pathogenesis of CP. We therefore performed whole mouse genome Affymetrix microarray analysis of pancreatic gene expression of C57BL/6J and C57BL/6NHsd before and after induction of CP. Genes with differentially regulated expression between the two substrains that might be candidates in CP progression included Mmp7, Pcolce2, Itih4, Wdfy1, and Vtn. We also identified several genes associated with development of CP in both substrains, including RIKEN cDNA 1810009J06 gene (trypsinogen 5), Ccl8, and Ccl6.

Genetic risk factors for pancreatic disorders

A combination of genetic, environmental, and metabolic factors contribute to the development and recurrence of acute and chronic pancreatitis; information on all of these is required to manage patients effectively. For example, variants that affect regulation of the protease, serine (PRSS)1-PRSS2, and claudin (CLDN)2 loci, rather than their coding sequences, interact with other genetic and environmental factors to affect disease development. New strategies are needed to use these data and determine their contribution to pathogenesis, because these variants differ from previously studied, rare variants in exons (coding regions) of genes such as PRSS1, SPINK1, cystic fibrosis transmembrane conductance regulator (CFTR), chymotrypsin (CTR)C, and calcium-sensing receptor (CASR). Learning how various genetic factors affect pancreatic cells and systems could lead to etiology-based therapies rather than treatment of symptoms.

Inflammation, autophagy, and obesity: common features in the pathogenesis of pancreatitis and pancreatic cancer

Inflammation and autophagy are cellular defense mechanisms. When these processes are deregulated (deficient or overactivated) they produce pathologic effects, such as oxidative stress, metabolic impairments, and cell death. Unresolved inflammation and disrupted regulation of autophagy are common features of pancreatitis and pancreatic cancer. Furthermore, obesity, a risk factor for pancreatitis and pancreatic cancer, promotes inflammation and inhibits or deregulates autophagy, creating an environment that facilitates the induction and progression of pancreatic diseases. However, little is known about how inflammation, autophagy, and obesity interact to promote exocrine pancreatic disorders. We review the roles of inflammation and autophagy, and their deregulation by obesity, in pancreatic diseases. We discuss the connections among disordered pathways and important areas for future research.

Role of immune cells and immune-based therapies in pancreatitis and pancreatic ductal adenocarcinoma

Immune cells are important in the pathogenesis of acute pancreatitis and determine disease severity. Results from cytokine-based clinical trials for acute pancreatitis have been disappointing, so strategies that target and alter the behavior of infiltrating immune cells require consideration. Recurrent acute pancreatitis can progress to chronic pancreatitis, which is a well-described risk factor for pancreatic ductal adenocarcinoma (PDA). However, most patients with chronic pancreatitis do not develop PDA, and most patients with PDA do not have a history of pancreatitis. Interestingly, chronic pancreatitis and PDA tissues have similarities in their desmoplasia and inflammatory infiltrates, indicating overlapping inflammatory responses. Further studies are needed to determine the differences and similarities of these responses, improve our understanding of PDA pathogenesis, and develop specific immune-based therapies. Immune cells in PDA produce immunosuppressive signals that allow tumors to evade the immune response. Unlike single therapeutic agent studies that block immunosuppressive mechanisms, studies of combination therapies that include therapeutic vaccines have provided promising results.

Clinical profile and outcome of chronic pancreatitis in children

OBJECTIVE

To evaluate the etiology, presentation, complications and management of chronic pancreatitis in children.

DESIGN

Retrospective chart review.

SETTING

Gastroenterology department at Christian Medical College and Hospital, Vellore, India between January 2005 and December 2010.

PARTICIPANTS

99 Children (>18 yrs) diagnosed with chronic pancreatitis based on clinical and imaging features.

MAIN OUTCOME MEASURES

Etiology, clinical presentation, complications and management of chronic pancreatitis in children.

RESULTS

Of 3887 children who attended the Gastroenterology department, 99(2.5%) had chronic pancreatitis, of which 60 (60.6%) were males. In 95(95.9%) patients no definite cause was detected and they were labeled as Idiopathic chronic pancreatitis. All patients had abdominal pain, while 9(9.1%) had diabetes mellitus. Of the 22 children tested for stool fat, 10(45.5%) had steatorrhea. Pancreatic calcification was seen in 69 (69.7%). 68 (71.6%) patients with idiopathic chronic pancreatitis had calcification. Calcific idiopathic chronic pancreatitis was more frequent in males (67.6% vs. 48.1%, P=0.07), and was more commonly associated with diabetes mellitus (13.2% vs. none, P=0.047) and steatorrhea (61.5% vs. 16.7%, P=0.069). Pseudocyst (17.1%) and ascites (9.1%) were the most common complications. All children were treated with pancreatic enzyme supplements for pain relief. 57 patients were followed up. With enzyme supplementation, pain relief was present in 32 (56.1%) patients. Of those who did not improve, 10 underwent endotherapy and 15 underwent surgery. Follow up of 8 patients who underwent endotherapy, showed that 5 (62.5%) had relief. Follow up of 11 patients who underwent surgery showed that only 3 (27%) had pain relief. There was no death.

CONCLUSIONS

Idiopathic chronic pancreatitis is the predominant form of chronic pancreatitis in children and adolescents. It can present with or without calcification. The calcific variety is an aggressive disease characterized by early morphological and functional damage to the pancreas.

Antioxidant status and oxidative stress markers in pancreatic cancer and chronic pancreatitis

OBJECTIVES

Oxidative stress has been implicated in the pathogenesis of chronic pancreatitis (CP) and pancreatic cancer (PC). The study aim was to assess the oxidative stress markers and antioxidant defense system in patients with CP and those with PC.

METHODS

Activities of superoxide dismutase 1 (SOD1), catalase (CAT), glutathione peroxidase 1 (GPX1), glutathione reductase (GR), arylesterase (PON1-A) and lactonase (PON1-L) activities of paraoxonase 1 (PON1) and concentrations of reduced glutathione, conjugated dienes in low-density lipoprotein (CD/LDL) and oxidized LDL (ox-LDL/LDL) were assessed in 50 PC and 50 CP patients and 50 age and sex-matched controls.

RESULTS

Comparison of PC and CP groups to controls found the following changes: glutathione peroxidase 1 (GPX1) (-20.2%, -25.5%; P < 0.001), glutathione reductase (GR) (-9.5%, -11.9%; P < 0.05), SOD1 (+22.9%; P < 0.01), CAT (-10.6%; P < 0.05), PON1-A (-34.3%, -16.0%; P < 0.001), PON1-L (-44.2%; -17.0%; P < 0.01), conjugated dienes in LDL (CD/LDL) (+20%, +33.3%; P < 0.05) and ox-LDL/LDL (+42.2%, +14.4%; P < 0.05). The patients with PC had changed activities and levels of SOD1 (+24.2%), CAT (-10.4); P < 0.01), PON1-A (-21.7%), PON1-L (-32.9%), and ox-LDL/LDL (+24.3%); (all P < 0.01) compared with the patients with CP.

CONCLUSIONS

Reduced antioxidant defense system capacity and increased markers of oxidative stress were found in PC and CP. PON1-L and CAT activities, along with ox-LDL/LDL levels, were the independent factors differentiating the patients with PC from the patients with CP.

Cerulein-induced chronic pancreatitis does not require intra-acinar activation of trypsinogen in mice

BACKGROUND & AIMS

Premature activation of trypsinogen activation can cause pancreatic injury and has been associated with chronic pancreatitis (CP). Mice that lack intra-acinar activation of trypsinogen, such as trypsinogen-7-null (T(-/-)) and cathepsin B-null (CB(-/-)) mice, have been used to study trypsin-independent processes of CP development. We compared histologic features and inflammatory responses of pancreatic tissues from these mice with those from wild-type mice after the development of CP.

METHODS

CP was induced in wild-type, T(-/-), and CB(-/-) mice by twice-weekly induction of acute pancreatitis for 10 weeks; acute pancreatitis was induced by hourly intraperitoneal injections of cerulein (50 μg/kg × 6). Pancreatic samples were collected and evaluated by histologic and immunohistochemical analyses. Normal human pancreas samples, obtained from the islet transplant program at the University of Minnesota, were used as controls and CP samples were obtained from surgical resections.

RESULTS

Compared with pancreatic tissues from wild-type mice, those from T(-/-) and CB(-/-) mice had similar levels of atrophy, histomorphologic features of CP, and chronic inflammation. All samples had comparable intra-acinar activation of nuclear factor (NF)-κB, a transcription factor that regulates the inflammatory response, immediately after injection of cerulein. Pancreatic tissue samples from patients with CP had increased activation of NF-κB (based on nuclear translocation of p65 in acinar cells) compared with controls.

CONCLUSIONS

Induction of CP in mice by cerulein injection does not require intra-acinar activation of trypsinogen. Pancreatic acinar cells of patients with CP have increased levels of NF-κB activation compared with controls; regulation of the inflammatory response by this transcription factor might be involved in the pathogenesis of CP.

Early surgery versus optimal current step-up practice for chronic pancreatitis (ESCAPE): design and rationale of a randomized trial

Background

In current practice, patients with chronic pancreatitis undergo surgical intervention in a late stage of the disease, when conservative treatment and endoscopic interventions have failed. Recent evidence suggests that surgical intervention early on in the disease benefits patients in terms of better pain control and preservation of pancreatic function. Therefore, we designed a randomized controlled trial to evaluate the benefits, risks and costs of early surgical intervention compared to the current stepwise practice for chronic pancreatitis.

Methods/design

The ESCAPE trial is a randomized controlled, parallel, superiority multicenter trial. Patients with chronic pancreatitis, a dilated pancreatic duct (≥ 5 mm) and moderate pain and/or frequent flare-ups will be registered and followed monthly as potential candidates for the trial. When a registered patient meets the randomization criteria (i.e. need for opioid analgesics) the patient will be randomized to either early surgical intervention (group A) or optimal current step-up practice (group B). An expert panel of chronic pancreatitis specialists will oversee the assessment of eligibility and ensure that allocation to either treatment arm is possible. Patients in group A will undergo pancreaticojejunostomy or a Frey-procedure in case of an enlarged pancreatic head (≥ 4 cm). Patients in group B will undergo a step-up practice of optimal medical treatment, if needed followed by endoscopic interventions, and if needed followed by surgery, according to predefined criteria. Primary outcome is pain assessed with the Izbicki pain score during a follow-up of 18 months. Secondary outcomes include complications, mortality, total direct and indirect costs, quality of life, pancreatic insufficiency, alternative pain scales, length of hospital admission, number of interventions and pancreatitis flare-ups. For the sample size calculation we defined a minimal clinically relevant difference in the primary endpoint as a difference of at least 15 points on the Izbicki pain score during follow-up. To detect this difference a total of 88 patients will be randomized (alpha 0.05, power 90%, drop-out 10%).

Discussion

The ESCAPE trial will investigate whether early surgery in chronic pancreatitis is beneficial in terms of pain relief, pancreatic function and quality of life, compared with current step-up practice.

Trial registration

ISRCTN: ISRCTN45877994

Physical and mental quality of life in chronic pancreatitis: a case-control study from the North American Pancreatitis Study 2 cohort

OBJECTIVES

The objective of this study was to define the quality of life (QOL) in patients with chronic pancreatitis (CP).

METHODS

We studied 443 well-phenotyped CP subjects and 611 control subjects prospectively enrolled from 20 US centers between 2000 and 2006 in the North American Pancreatitis Study 2. Responses to the SF-12 questionnaire were used to calculate the mental (MCS) and physical component summary scores (PCS) with norm-based scoring (normal ≥50). Quality of life in CP subjects was compared with control subjects after controlling for demographic factors, drinking history, smoking, and medical conditions. Quality of life in CP was also compared with known scores for several chronic conditions.

RESULTS

Both PCS (38 [SD, 11.5] vs 52 [SD, 9.4]) and MCS (44 [SD, 11.5] vs 51 [SD, 9.2]) were significantly lower in CP compared with control subjects (P < 0.001). On multivariable analyses, compared with control subjects, a profound decrease in physical QOL (PCS 12.02 points lower) and a clinically significant decrease in mental QOL (MCS 4.24 points lower) was seen due to CP. Quality of life in CP was similar to (heart, kidney, liver, lung disease) or worse than (nonskin cancers, diabetes mellitus, hypertension, rheumatoid arthritis) other chronic conditions.

CONCLUSIONS

The impact of CP on QOL appears substantial. The QOL in CP subjects appears to be worse or similar to the QOL of many other chronic conditions.

A comprehensive study indicates PRSS1 gene is significantly associated with pancreatitis

This comprehensive meta-analysis was applied to case-control studies of the association between pancreatitis and PRSS1 gene to assess the joint evidence for the association, the influence of individual studies, and evidence for publication bias. PubMed, EMBASE, and Cochrane Library were searched in order to identify longitudinal studies evaluating pancreatitis disease and PRSS1 gene. Odds ratios (ORs) were pooled using a random-effects model. For the case-control studies, the authors found 1) support for the association between total pancreatitis and PRSS1 gene, both totally analyzed and subdivided analyzed {total: [OR:10.799, 95%CI:(5.489-21.242), p<0.000]; Europe: [OR:9.795, 95%CI:(2.923-32.819), p<0.000]; Asia: [OR:11.994, 95%CI:(5.156-27.898), p<0.000]}. 2) no evidence showed that this association was accounted for by any one study, and 3) no evidence showed any publication bias exist. In conclusion, PRSS1 gene was significantly associated with total pancreatitis disease, both totally and separately.

Deletion of IκBα activates RelA to reduce acute pancreatitis in mice through up-regulation of Spi2A

BACKGROUND & AIMS

The transcription factor nuclear factor-κB (NF-κB) (a heterodimer of NF-κB1p50 and RelA) is activated rapidly in acute pancreatitis (AP). However, it is not clear whether NF-κB promotes or protects against AP. We used the NF-κB inhibitor protein, inhibitor of κB (IκB)α, to study the roles of NF-κB in the development of AP in mice.

METHODS

IκBα or the combination of IκBα and RelA selectively were deleted from pancreas of mice using the Cre/locus of cross-over P strategy; cerulein or L-arginine were used to induce AP. We performed microarray analyses of the IκBα- and RelA-deficient pancreata. DNA from healthy individuals and patients with acute or chronic pancreatitis were analyzed for variants in coding regions of alpha-1-antichymotrypsin.

RESULTS

Mice with pancreas-specific deletion of IκBα had constitutive activation of RelA and a gene expression profile consistent with NF-κB activation; development of AP in these mice was attenuated and trypsin activation was impaired. However, AP was fully induced in mice with pancreas-specific deletion of IκBα and RelA. By using genome-wide expression analysis, we identified a cluster of NF-κB-regulated genes that might protect against the development of AP. The serine protease inhibitor 2A (Spi2a) was highly up-regulated in IκBα-deficient mice. Lentiviral-mediated expression of Spi2A reduced the development of AP in C57BL/6 and RelA-deficient mice. However, we did not correlate any variants of alpha-1-antichymotrypsin, the human homologue of Spi2a, with acute or chronic pancreatitis.

CONCLUSIONS

Pancreas-specific deletion of IκBα results in nuclear translocation of RelA and reduces AP induction and trypsin activation in mice after administration of cerulein or L-arginine. Constitutive activation of RelA up-regulates Spi2A, which protects mice against the development of AP.

The contribution of the SPINK1 c.194+2T>C mutation to the clinical course of idiopathic chronic pancreatitis in Chinese patients

BACKGROUND

Recent data suggest that the serine protease inhibitor Kazal type 1 (SPINK1) gene mutation is associated with idiopathic chronic pancreatitis. However, few studies have focused on the serine protease inhibitor Kazal type 1 c.194+2T>C mutation. Therefore, our goal was to study the prevalence and impact of serine protease inhibitor Kazal type 1 mutations on the clinical profile of idiopathic chronic pancreatitis patients in China.

METHODS

A retrospective-cohort study of 118 Chinese patients with idiopathic chronic pancreatitis was performed, and genetic tests were carried out to detect SPINK1 mutations. Subjects without pancreatitis were used as controls. In total, 118 idiopathic chronic pancreatitis patients and 100 control subjects were evaluated.

RESULTS

The serine protease inhibitor Kazal type 1 c.194+2T>C variant was present in 44.9% of patients with idiopathic chronic pancreatitis. The frequency of diabetes in idiopathic chronic pancreatitis patients with the serine protease inhibitor Kazal type 1 c.194+2T>C mutation (39.6%) was higher than that of patients without the mutation (9.2%). The time to occurrence of diabetes mellitus after idiopathic chronic pancreatitis symptom onset is significantly influenced by the c.194+2T>C mutation (p<0.001). In addition, the mean age of diabetes onset in patients with the serine protease inhibitor Kazal type 1 c.194+2T>C mutation (38.33 ± 9.50) was significantly younger than that of patients without this mutation (49.67 ± 6.74).

CONCLUSIONS

The presence of the serine protease inhibitor Kazal type 1 c.194+2T>C mutation seems to be associated with idiopathic chronic pancreatitis and could predispose individuals to pancreatic diabetes onset at an earlier age.

Common genetic variants in the CLDN2 and PRSS1-PRSS2 loci alter risk for alcohol-related and sporadic pancreatitis

Pancreatitis is a complex, progressively destructive inflammatory disorder. Alcohol was long thought to be the primary causative agent, but genetic contributions have been of interest since the discovery that rare PRSS1, CFTR and SPINK1 variants were associated with pancreatitis risk. We now report two associations at genome-wide significance identified and replicated at PRSS1-PRSS2 (P < 1 × 10(-12)) and X-linked CLDN2 (P < 1 × 10(-21)) through a two-stage genome-wide study (stage 1: 676 cases and 4,507 controls; stage 2: 910 cases and 4,170 controls). The PRSS1 variant likely affects disease susceptibility by altering expression of the primary trypsinogen gene. The CLDN2 risk allele is associated with atypical localization of claudin-2 in pancreatic acinar cells. The homozygous (or hemizygous in males) CLDN2 genotype confers the greatest risk, and its alleles interact with alcohol consumption to amplify risk. These results could partially explain the high frequency of alcohol-related pancreatitis in men (male hemizygote frequency is 0.26, whereas female homozygote frequency is 0.07).

Determinants of chymotrypsin C cleavage specificity in the calcium-binding loop of human cationic trypsinogen

The pancreatic serine protease chymotrypsin C (CTRC) cleaves the Leu81-Glu82 peptide bond in the calcium-binding loop of human cationic trypsinogen and thereby promotes its degradation. This serves as a protective mechanism against ectopic trypsinogen activation in the pancreas. In the present study, we demonstrate that cleavage of the Leu81-Glu82 peptide bond by CTRC is highly specific, and other human pancreatic chymotrypsins (CTRB1, CTRB2 and CTRL1) and elastases (ELA2A, ELA3A and ELA3B) do not catalyze this reaction. To elucidate the mechanistic basis for CTRC specificity, we surveyed the primary (P1) cleavage preference of these pancreatic proteases on peptide substrates. We found that CTRC cleaved after a P1 Leu with at least tenfold higher catalytic efficiency than other enzymes tested. To assess extended sub-site interactions, we introduced Ala mutations into human cationic trypsinogen at the P3, P1' P3' and P4' amino acid positions, where P1-P1' corresponds to Leu81-Glu82. Interestingly, CTRC-mediated cleavage was stimulated threefold by mutation E82A and unaffected by mutations E79A and N84A, but all three mutations compromised specificity and resulted in increased cleavage by ELA2A. Mutation E85A decreased CTRC cleavage by twofold. Remarkably, other chymotrypsins and elastases did not cleave human cationic trypsinogen even with the L81F or L81A mutations, which introduced favorable P1 residues for these enzymes. We conclude that specific cleavage of the Leu81-Glu82 peptide bond in human cationic trypsinogen by CTRC is primarily determined by its distinctively high activity on leucyl peptide bonds, with the P1' Glu82, P3' Asn84 and P4' Glu85 residues serving as additional specificity determinants.

The Spanish Pancreatic Club's recommendations for the diagnosis and treatment of chronic pancreatitis: part 2 (treatment)

Chronic pancreatitis (CP) is a complex disease with a wide range of clinical manifestations. This range comprises from asymptomatic patients to patients with disabling symptoms or complications. The management of CP is frequently different between geographic areas and even medical centers. This is due to the paucity of high quality studies and clinical practice guidelines regarding its diagnosis and treatment. The aim of the Spanish Pancreatic Club was to give current evidence-based recommendations for the management of CP. Two coordinators chose a multidisciplinary panel of 24 experts on this disease. These experts were selected according to clinical and research experience in CP. A list of questions was made and two experts reviewed each question. A draft was later produced and discussed with the entire panel of experts in a face-to-face meeting. The level of evidence was based on the ratings given by the Oxford Centre for Evidence-Based Medicine. In the second part of the consensus, recommendations were given regarding the management of pain, pseudocysts, duodenal and biliary stenosis, pancreatic fistula and ascites, left portal hypertension, diabetes mellitus, exocrine pancreatic insufficiency, and nutritional support in CP.

Depressive Symptoms, Pain, and Quality of Life among Patients with Nonalcohol-Related Chronic Pancreatitis

Objective. The present study was conducted to determine if depressive symptoms were associated with variability in pain perception and quality of life among patients with nonalcohol-related chronic pancreatitis. Methods. The research design was cross-sectional, and self-report data was collected from 692 patients with nonalcohol-related, intractable pancreatitis. The mean age of the sample was 52.6 (SD = 14.7); 41% of the sample were male. Participants completed the MOS SF12 Quality of Life Measure, the Center for Epidemiological Studies 10-item Depression Scale (CESD), and a numeric rating scale measure of “pain on average” from the Brief Pain Inventory. Results. Depressive symptoms were significantly related to participants' reports of increased pain and decreased quality of life. The mean CESD score of the sample was 10.6 (SD = 6.5) and 52% of the sample scored above the clinical cutoff for the presence of significant depressive symptomology. Patients scoring above the clinical cutoff on the depression screening measure rated their pain as significantly higher than those below the cutoff (P < 0.0001) and had significantly lower physical quality of life (P < 0.0001) and lower mental quality of life (P < 0.0001). Conclusion. Although causality cannot be determined based on cross-sectional, correlational data, findings suggest that among patients with nonalcoholic pancreatitis, the presence of depressive symptoms is common and may be a risk factor associated with increased pain and decreased quality of life. Thus, routine screening for depressive symptomology among patients with nonalcoholic pancreatitis may be warranted.

Serum proteome profiling of pancreatitis using recombinant antibody microarrays reveals disease-associated biomarker signatures

PURPOSE

Pancreatitis is an inflammatory state of the pancreas, for which high-performing serological biomarkers are lacking. The aim of the present study was to evaluate the use of affinity proteomics for identifying potential markers of disease and stratifying pancreatitis subtypes.

EXPERIMENTAL DESIGN

High-content, recombinant antibody microarrays were applied for serum protein expression profiling of 113 serum samples from patients with chronic, acute, and autoimmune pancreatitis, as well as healthy controls. The sample groups were compared using supervised classification based on support vector machine analysis.

RESULTS

This discovery study showed that pancreatitis subtypes could be discriminated with high accuracy. Using unfiltered data, the individual subtypes, as well as the combined pancreatitis cohort, were distinguished from healthy controls with high AUC values (0.96-1.00). Moreover, characteristic protein patterns and AUC values in the range of 0.69-0.95 were observed for the individual pancreatitis entities when compared to each other, and to all other samples combined.

CONCLUSIONS AND CLINICAL RELEVANCE

This study demonstrated the potential of the antibody microarray approach for stratification of pancreatitis. Distinct candidate multiplex serum biomarker signatures for chronic, acute, and autoimmune pancreatitis were defined, which could enhance our fundamental knowledge of the underlying molecular mechanisms, and potentially lead to improved diagnosis.

A mass-spectroscopic method for measuring des-Leu albumin--a novel marker for chronic pancreatitis

OBJECTIVES

Chronic pancreatitis is a progressive inflammatory disease leading to pancreatic insufficiency. The diagnosis of chronic pancreatitis is challenging, especially in early disease and the current tests have low sensitivity, may be invasive or have limited availability. We previously identified a truncated form of albumin lacking the C-terminal leucine, des-Leu albumin, which was present at high concentration in pancreatitis. We have developed a liquid-chromatography tandem-mass spectrometry (LC-MS/MS) method for measuring this peptide and make some preliminary observations on patient samples.

METHODS

Serum samples from patients with established pancreatitis and controls were obtained. Diluted serum samples or prepared standards were digested with trypsin. Aliquots of the digest were separated on a reversed-phase column using water:acetonitrile:formic acid mobile-phase with tandem-mass spectrometry detection. Percentage composition of des-Leu albumin was determined from a response curve.

RESULTS

The C-terminal peptide, LVAASQAALG- of des-Leu albumin was identified by m/z 901→725, wild type albumin by m/z 1014→825. Additional fragments were monitored as internal reference for digestion and sample integrity. Inter-assay imprecision was estimated at 10%. The percentage composition of des-Leu albumin segregated with the diagnosis of established pancreatitis with median levels of des-Leu albumin of 68% in patients compared to 5% in controls.

CONCLUSIONS

Des-Leu albumin is a promising novel biomarker for chronic pancreatitis. It allowed clear discrimination of patients with pancreatitis from controls and its long half-life may facilitate monitoring of disease activity. The method described could readily be undertaken in modern clinical chemistry laboratories and will form the basis for further study.

Genetics and pathogenesis of chronic pancreatitis: the 2012 update

Chronic pancreatitis is a persistent inflammation of the pancreas that results in irreversible morphological changes and impairment of both exocrine and endocrine functions. Genetic studies of the disease over the past 15 years have led to the identification of four firmly established susceptibility genes namely PRSS1, SPNIK1, CTRC and CFTR. Our previously published review (Chen and Férec. Annu Rev Genomics Hum Genet 2009) has comprehensively summarized the advances made in terms of genetics and pathogenesis of chronic pancreatitis, covering the data available up to early 2009. This review summarizes the important and representative findings published thereafter, focusing on (i) newly found disease-causing mutations, (ii) functional characterization of known variations and (iii) genotype and phenotype relationship.

Chronic pancreatitis in dogs: a retrospective study of clinical, clinicopathological, and histopathological findings in 61 cases

The objective of this study was to characterize the clinical, clinicopathological, and histopathological findings of dogs with chronic pancreatitis. The necropsy database at Texas A&M University was searched for reports of dogs with histological evidence of chronic pancreatitis defined as irreversible histologic changes of the pancreas (i.e. fibrosis or atrophy). A reference necropsy population of 100 randomly selected dogs was used for signalment and concurrent disease comparisons. Cases were categorized as clinical or incidental chronic pancreatitis based on the presence of vomiting, decreased appetite, or both vs. neither of these signs. All archived pancreas samples were scored histologically using a published scoring system. Sixty-one dogs with chronic pancreatitis were included. The most frequent clinical signs were lethargy, decreased appetite, vomiting, and diarrhea. Compared to the reference necropsy population, chronic pancreatitis cases were more likely to be older, neutered, of the non-sporting/toy breed group, and to have concurrent endocrine, hepatobiliary, or neurological disease. Clinical cases had significantly higher histological scores for pancreatic necrosis and peripancreatic fat necrosis, and were significantly more likely to have hepatobiliary or endocrine disease as well as increased liver enzyme activities, or elevated cholesterol and bilirubin concentrations. In conclusion, clinical disease resulting from chronic pancreatitis might be related to the presence of pancreatic necrosis and pancreatic fat necrosis. The signalment, presentation, and concurrent diseases of dogs with chronic pancreatitis are similar to those previously reported for dogs with acute pancreatitis.

SEC23B is required for the maintenance of murine professional secretory tissues

In eukaryotic cells, newly synthesized secretory proteins require COPII (coat protein complex II) to exit the endoplasmic reticulum (ER). COPII contains five core components: SAR1, SEC23, SEC24, SEC13, and SEC31. SEC23 is a GTPase-activating protein that activates the SAR1 GTPase and also plays a role in cargo recognition. Missense mutations in the human COPII paralogues SEC23A and SEC23B result in craniolenticulosutural dysplasia and congenital dyserythropoietic anemia type II, respectively. We now report that mice completely deficient for SEC23B are born with no apparent anemia phenotype, but die shortly after birth, with degeneration of professional secretory tissues. In SEC23B-deficient embryonic pancreas, defects occur in exocrine and endocrine tissues shortly after differentiation. Pancreatic acini are completely devoid of zymogen granules, and the ER is severely distended. Similar ultrastructural alterations are also observed in salivary glands, but not in liver. Accumulation of proteins in the ER lumen activates the proapoptotic pathway of the unfolded protein response, suggesting a central role for apoptosis in the degeneration of these tissues in SEC23B-deficient embryos. Although maintenance of the secretory pathway should be required by all cells, our findings reveal a surprising tissue-specific dependence on SEC23B for the ER exit of highly abundant cargo, with high levels of SEC23B expression observed in professional secretory tissues. The disparate phenotypes in mouse and human could result from residual SEC23B function associated with the hypomorphic mutations observed in humans, or alternatively, might be explained by a species-specific shift in function between the closely related SEC23 paralogues.

Heme oxygenase, inflammation, and fibrosis: the good, the bad, and the ugly?

Upon injury, prolonged inflammation and oxidative stress may cause pathological wound healing and fibrosis, leading to formation of excessive scar tissue. Fibrogenesis can occur in most organs and tissues and may ultimately lead to organ dysfunction and failure. The underlying mechanisms of pathological wound healing still remain unclear, and are considered to be multifactorial, but so far, no efficient anti-fibrotic therapies exist. Extra- and intracellular levels of free heme may be increased in a variety of pathological conditions due to release from hemoproteins. Free heme possesses pro-inflammatory and oxidative properties, and may act as a danger signal. Effects of free heme may be counteracted by heme-binding proteins or by heme degradation. Heme is degraded by heme oxygenase (HO) that exists as two isoforms: inducible HO-1 and constitutively expressed HO-2. HO generates the effector molecules biliverdin/bilirubin, carbon monoxide, and free iron/ferritin. HO deficiency in mouse and man leads to exaggerated inflammation following mild insults, and accumulating epidemiological and preclinical studies support the widely recognized notion of the cytoprotective, anti-oxidative, and anti-inflammatory effects of the activity of the HO system and its effector molecules. In this review, we address the potential effects of targeted HO-1 induction or administration of HO-effector molecules as therapeutic targets in fibrotic conditions to counteract inflammatory and oxidative insults. This is exemplified by various clinically relevant conditions, such as hypertrophic scarring, chronic inflammatory liver disease, chronic pancreatitis, and chronic graft rejection in transplantation.

Successful treatment of benign biliary stricture by a covered self-expandable metallic stent in a patient with chronic pancreatitis

The patient was a 73 year old man for whom surgery under general anesthesia was difficult to perform because of pulmonary emphysema. In April 2003, he visited our hospital complaining of epigastralgia and dorsal pain, and was admitted under a diagnosis of acute exacerbation of chronic pancreatitis. In 2005, acute cholangitis concomitantly developed with acute exacerbation of chronic pancreatitis, for which a plastic stent was placed in the common bile duct. Cholangitis repeatedly developed every 2-3 months thereafter, and admission was required each time to exchange the stent. Surgery was considered but not applicable because of his poor respiratory function, and a partially covered self-expandable metallic stent was inevitably placed in the bile duct. Ten months later, an aberration of the metallic stent in the bile duct occurred, but it was dealt with by placing an additional metallic stent, and no cholangitis or pancreatitis developed until the patient died of respiratory insufficiency 3 years later. Placement of a covered self-expandable metallic stent might be an option for the treatment of benign biliary stricture, especially in patients at high risk from surgery.

Genetics of pancreatitis: an update for clinicians and genetic counselors

With novel genetic technologies available, there is a paradigm shift in the way that risk assessments, diagnoses,and therapies for genetic susceptibility syndromes are addressed. Hereditary pancreatitis is among these conditions, for which genetic counseling and next generation sequencing, help families better understand, cope with and live healthier lives. Identifying a genetic etiology to a condition formally believed to be solely environmentally induced can alter the path for treatment for many patients. This finding introduces the concept of gene-environment interactions in human disease and the relationship between genetic predisposition and exposure risk in disease development. The genetic counseling process is complex with medical explanations, psychosocial issues relating to coping with diagnosis, potential future health problems, recurrence risks and family planning. These sometimes difficult conversations can be facilitated by a genetic counselor as a member of the multidisciplinary team. This chapter addresses the intricate medical and psychosocial issues that can arise in the setting of treating patients with hereditary pancreatitis.

Bone marrow-derived cells contribute to cerulein-induced pancreatic fibrosis in the mouse

Bone marrow (BM) cells may transdifferentiate into circulating fibrocytes and myofibroblasts in organ fibrosis. In this study, we investigated the contribution and functional roles of BM-derived cells in murine cerulein-induced pancreatic fibrosis. C57/BL6 female mice wild-type (WT) or Col 1α1(r/r) male BM transplant, received supraphysiological doses of cerulein to induce pancreatic fibrosis. The CD45(+)Col 1(+) fibrocytes isolated from peripheral blood (PB) and pancreatic tissue were examined by in situ hybridization for Y chromosome detection. The number of BM-derived myofibroblasts, the degree of Sirius red staining and the levels of Col 1α1 mRNA were quantified. The Y chromosome was detected in the nuclei of PB CD45(+)Col 1(+) fibrocytes, confirming that circulating fibrocytes can be derived from BM. Co-expression of α-smooth muscle actin illustrated that fibrocytes can differentiate into myofibroblasts. The number of BM-derived myofibroblasts, degree of collagen deposition and pro-collagen I mRNA expression were higher in the mice that received Col 1α1(r/r) BM, (cells that produce mutated, collagenase-resistant collagen) compared to WT BM, indicating that the genotype of BM cells can alter the degree of pancreatic fibrosis. Our data indicate that CD45(+)Col 1(+) fibrocytes in the PB can be BM-derived, functionally contributing to cerulein-induced pancreatic fibrosis in mice by differentiating into myofibroblasts.

Endoscopic or surgical intervention for painful obstructive chronic pancreatitis

BACKGROUND

Endoscopy and surgery are the treatment modalities of choice in patients with obstructive chronic pancreatitis. Physicians face the decision between endoscopy and surgery for this group of patients, without clear consensus.

OBJECTIVES

To assess and compare the effectiveness and complications of surgical and endoscopic interventions in the management of pain for obstructive chronic pancreatitis.

SEARCH METHODS

We searched The Cochrane Library, MEDLINE, EMBASE and the Conference Proceedings Citation Index; and performed a cross-reference search. Two review authors performed the selection of trials independently.

SELECTION CRITERIA

All randomised controlled trials (RCTs) investigating endoscopic or surgical interventions for obstructive chronic pancreatitis. All trials were included irrespective of blinding, number of patients randomised and language of the article.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from the articles. The methodological quality of included trials was evaluated. Authors were requested additional information in the case of missing data.

MAIN RESULTS

We screened 2082 publications and identified three eligible trials. Two trials compared endoscopic intervention to surgical intervention. These included a total of 111 patients, 55 in the endoscopic group and 56 in the surgical group. A higher proportion of patients with pain relief was found in the surgical group compared to the endoscopic group (partial or complete pain relief: RR 1.62, 95% confidence interval (CI) 1.11 to 2.37; complete pain relief: RR 2.45, 95% CI 1.18 to 5.09). Surgical intervention resulted in improved quality of life and improved preservation of exocrine pancreatic function in one trial. The number of patients did not allow for a reliable evaluation of morbidity and mortality between the two treatment modalities. One trial compared surgical intervention to conservative treatment. It included 32 patients: 17 in the surgical group and 15 in the conservative group. The trial showed that surgical intervention resulted in a higher percentage of patients with pain relief and better preservation of pancreatic function. The trial had methodological limitations and the number of patients was relatively small.

AUTHORS' CONCLUSIONS

For patients with obstructive chronic pancreatitis and dilated pancreatic duct, this review showed that surgery is superior to endoscopy in terms of pain control. Morbidity and mortality seemed not to differ between the two intervention modalities, but the small trials identified do not provide sufficient power to detect the small differences expected in this outcome.Regarding the comparison of surgical intervention versus conservative treatment, this review has shown that surgical intervention in an early stage of chronic pancreatitis seems to be a promising approach in terms of pain control and pancreatic function. Confirmation of these results is needed in other trials due to the methodological limitations and limited number of patients of the present evidence.

Spinal microglia initiate and maintain hyperalgesia in a rat model of chronic pancreatitis

BACKGROUND & AIMS

The chronic, persistent pain associated with chronic pancreatitis (CP) has many characteristics of neuropathic pain, initiated and maintained by the activation of spinal microglia. We investigated whether activated microglia in the thoracic spinal cord contribute to chronic pain in a rat model of CP.

METHODS

CP was induced in Sprague-Dawley rats by an intraductal injection of 2% trinitrobenzene sulfonic acid. Hyperalgesia was assessed by the measurement of mechanical sensitivity of the abdomen and nocifensive behavior to electrical stimulation of the pancreas. Three weeks after induction of CP, spinal samples were analyzed by immunostaining and immunoblot analyses for levels of CD11 (a marker of microglia, determined with the antibody OX42) and phosphorylated p38 (P-p38, a marker of activation of p38 mitogen-activated protein kinase signaling). We examined the effects of minocycline (inhibitor of microglia) and fractalkine (microglia-activating factor) on visceral hyperalgesia in rats with CP.

RESULTS

Rats with CP had increased sensitivity and nociceptive behaviors to mechanical probing of the abdomen and electrical stimulation of the pancreas. The dorsal horn of the thoracic spinal cords of rats with CP contained activated microglia (based on increased staining with OX42), with an ameboid appearance. Levels of P-p38 increased in rats with CP and colocalized with OX42-positive cells. Intrathecal injection of minocycline reversed and prevented the increase of nocifensive behaviors and levels of P-p38 in rats with CP. Fractalkine induced hyperalgesia in rats without CP, which was blocked by minocycline.

CONCLUSIONS

Activated spinal microglia have important roles in maintaining and initiating chronic pain in a rat model of CP. Microglia might be a target for treatment of hyperalgesia caused by pancreatic inflammation.

The rosemont criteria can predict the pain response to pancreatic enzyme supplementation in patients with suspected chronic pancreatitis undergoing endoscopic ultrasoun

Background/Aims

The Rosemont classification system was designed to standardize the endosonographic assessment of chronic pancreatitis. To determine whether the Rosemont classification system can predict the response to pancreatic enzyme supplementation in patients undergoing endoscopic ultrasound (EUS) evaluation of suspected chronic pancreatitis.

Methods

Sixty-five patients were included with abdominal pain undergoing endosonography for suspected chronic pancreatitis were included. Patients completed a questionnaire for evaluation of their abdominal pain. Group 1 (n=13) had EUS findings consistent with or suggestive of chronic pancreatitis. Group 2 (n=45) had EUS findings that were normal or indeterminate in the Rosemont classification system. Patients were given pancreatic enzyme supplementation and then given a follow-up pain questionnaire for a mean of 37 days subsequent to EUS regarding the change in pain.

Results

Group 1 patients were more likely to have a response to pancreatic enzymes (62% vs 24%, p=0.012) and a decrease in their pain scale ratings (2.62 vs 0.29, p=0.01). Computed tomography findings of chronic pancreatitis and narcotic use did not predict the response to pancreatic enzyme supplementation. The individual Rosemont criteria of hyperechoic foci with shadowing (p=0.03), lobularity (p=0.02), and stranding (p=0.001) were associated with improvement of pain after treatment.

Conclusions

The Rosemont classification system can identify patients who are more likely to have improvement in abdominal pain after treatment with pancreatic enzyme supplementation.

The fibrosis of chronic pancreatitis: new insights into the role of pancreatic stellate cells

SIGNIFICANCE

Prominent fibrosis is a major histological feature of chronic pancreatitis, a progressive necroinflammatory condition of the pancreas, most commonly associated with alcohol abuse. Patients with this disease often develop exocrine and endocrine insufficiency characterized by maldigestion and diabetes. Up until just over a decade ago, there was little understanding of the pathogenesis of pancreatic fibrosis in chronic pancreatitis.

RECENT ADVANCES

In recent times, significant progress has been made in this area, mostly due to the identification, isolation, and characterization of the cells, namely pancreatic stellate cells (PSCs) that are now established as key players in pancreatic fibrogenesis. In health, PSCs maintain normal tissue architecture via regulation of the synthesis and degradation of extracellular matrix (ECM) proteins. During pancreatic injury, PSCs transform into an activated phenotype that secretes excessive amounts of the ECM proteins that comprise fibrous tissue.

CRITICAL ISSUES

This Review summarizes current knowledge and critical aspects of PSC biology which have been increasingly well characterized over the past few years, particularly with respect to the response of PSCs to factors that stimulate or inhibit their activation and the intracellular signaling pathways governing these processes. Based on this knowledge, several therapeutic strategies have been examined in experimental models of pancreatic fibrosis, demonstrating that pancreatic fibrosis is a potentially reversible condition, at least in early stages.

FUTURE DIRECTIONS

These will involve translation of the laboratory findings into effective clinical approaches to prevent/inhibit PSC activation so as to prevent, retard, or reverse the fibrotic process in pancreatitis.

Assessment of the protective effects of oral tocotrienols in arginine chronic-like pancreatitis

Tocotrienols exhibit anti-inflammatory properties over macrophages and promote cytotoxicity in activated pancreatic stellate cells, suggesting that they may limit chronic pancreatitis progression. We aimed to quantitate the effect of oral tocotrienols on a rat model of chronic pancreatic injury. Chronic-like pancreatitis was induced by repeated arginine pancreatitis. Palm oil tocotrienol-rich fraction (TRF) was given by gavage before and after pancreatitis inductions. Amylase and hydroxyproline were determined in pancreatic homogenates; collagen, fibronectin, α-smooth muscle actin (SMA), glial fibrillary acidic protein (GFAP), and phosphorylated Smad3 were assessed by Western blotting. Transforming growth factor (TGF)-β1 was measured in plasma. Morphological assessment included light microscopy, fibrosis area fraction, and collagen network fractal analysis. Arginine pancreatitis induced pancreatic atrophy and increased hydroxyproline that ameliorated after TRF. Arginine increased TGF-β1 (185 ± 40 vs. 15 ± 2 ng/ml; P <0.01) that was blunted by TRF (53 ± 19; P < 0.01). TRF reduced protease and Smad3 activation, collagen, and fibronectin. α-SMA increased and GFAP diminished in arginine pancreatitis, consistent with long-term stellate cell activation, and TRF reverted these changes to basal. Arginine pancreatitis increased fibrosis area fraction (4.5 ± 0.3% vs. 0.2 ± 0.2%), collagen network complexity (fractal dimension 1.52 ± 0.03 vs. 1.42 ± 0.01; P < 0.001), and inhomogeneity (lacunarity 0.63 ± 0.03 vs. 0.40 ± 0.02; P < 0.001), which were all reduced by TRF (1.3 ± 0.4%, 1.43 ± 0.02%, and 0.51 ± 0.03%, respectively; P < 0.01). Best correlation coefficients were obtained when comparing fibrosis area fraction with lacunarity (r = 0.88) and both parameters with pancreatic weight (r = -0.91 and -0.79, respectively). TRF administered only before pancreatitis best, but not fully, recapitulated the beneficial effects of TRF. Tocotrienols improve quantitative measures of chronic pancreatic damage. They may be of benefit in human chronic pancreatitis.

The complex exocrine-endocrine relationship and secondary diabetes in exocrine pancreatic disorders

The pancreas is a dual organ with exocrine and endocrine functions. The interrelationship of the endocrine-exocrine parts of the pancreas is a complex one, but recent clinical and experimental studies have expanded our knowledge. Many disorders primarily of the exocrine pancreas, often solely in the clinical realm of gastroenterologists are associated with diabetes mellitus (DM). Although, the DM becoming disorders are often grouped with type 2 diabetes, the pathogenesis, clinical manifestations and management differ. We review here data on the association of exocrine-endocrine pancreas, the many hormones of the pancreas and their possible effects on the exocrine functions followed by data on the epidemiology, pathogenesis, and management of DM in chronic pancreatitis, cystic fibrosis, pancreatic cancer, and clinical states after pancreatic surgery.

Difference gel electrophoresis identifies differentially expressed proteins in endoscopically collected pancreatic fluid

Alterations in the pancreatic fluid proteome of individuals with chronic pancreatitis (CP) may offer insights into the development and progression of the disease. The endoscopic pancreatic function test (ePFT) can safely collect large volumes of pancreatic fluid that are potentially amenable to proteomic analyses using difference gel electrophoresis (DIGE) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Pancreatic fluid was collected endoscopically using the ePFT method following secretin stimulation from three individuals with severe CP and three chronic abdominal pain (CAP) controls. The fluid was processed to minimize protein degradation and the protein profiles of each cohort, as determined by DIGE and LC-MS/MS, were compared. This DIGE-LC-MS/MS analysis reveals proteins that are differentially expressed in CP compared with CAP controls. Proteins with higher abundance in pancreatic fluid from CP individuals include: actin, desmoplankin, α-1-antitrypsin, SNC73, and serotransferrin. Those of relatively lower abundance include carboxypeptidase B, lipase, α-1-antichymotrypsin, α-2-macroglobulin, actin-related protein (Arp2/3) subunit 4, glyceraldehyde-3-phosphate dehydrogenase, and protein disulfide isomerase. Endoscopic collection (ePFT) in tandem with DIGE-LC-MS/MS is a suitable approach for pancreatic fluid proteome analysis; however, further optimization of our protocol, as outlined herein, may improve proteome coverage in future analyses.

Comparison of antioxidative and antifibrotic effects of α-tocopherol with those of tocotrienol-rich fraction in a rat model of chronic pancreatitis

OBJECTIVES

The α-tocopherol and tocotrienol-rich fraction (TRF) are considered effective antioxidants. This study aimed to compare the antioxidative and antifibrotic effects of α-tocopherol and TFR in dibutylin dichloride (DBTC)-induced chronic pancreatitis (CP) rats.

METHODS

Oral administration of α-tocopherol and TFR (both 800 mg/kg per day) started the next day after DBTC (8 mg/kg) infusion into the tail vein for 4 weeks. Histological examination, Sirius red staining, and measurement of the contents of hydroxyproline and malondialdehyde of the pancreas were performed to evaluate pancreatic damage and fibrosis. Immunohistochemical analysis of α-smooth muscle actin and real-time reverse transcription polymerase chain reaction for transforming growth factor-β1 (TGF-β1) and collagen-α1(I) were performed to evaluate the activation of pancreatic stellate cells and the mRNA levels of fibrosis-related genes, respectively.

RESULTS

Both α-tocopherol and TRF reduced oxidative stress, ameliorated inflammation and fibrosis, and down-regulated the mRNA expression of TGF-β1 and collagen-α1(I) in DBTC-induced CP. The TRF was superior to α-tocopherol in alleviating inflammation and fibrosis and down-regulating TGF-β1 mRNA expression.

CONCLUSIONS

Oral administration of α-tocopherol and TRF improves pancreatic inflammation and fibrosis in DBTC-induced CP rats, with TRF being more effective than α-tocopherol. Therefore, TRF may be a novel option for alleviating inflammation and, particularly, the fibrotic process in CP.

Myeloid, but not pancreatic, RelA/p65 is required for fibrosis in a mouse model of chronic pancreatitis

BACKGROUND & AIMS

Little is known about how transcription factors might regulate pathogenesis of chronic pancreatitis (CP). We analyzed the in vivo role of RelA/p65, a component of the transcription factor nuclear factor (NF)-κB, in different cell types during development of CP in mice.

METHODS

RelA/p65 was functionally inactivated in the pancreas (relaΔpanc), in myeloid cells (relaΔmye), or both (relaΔpanc,Δmye) compartments using the Cre-loxP strategy. Experimental CP was induced with repetitive injections of cerulein over 6 weeks. Pancreata were investigated histologically and biochemically. We created an in vitro coculture assay of pancreatic stellate cells (PSC) and macrophages and performed gene arrays from pancreata and macrophages with functionally inactivated RelA/p65. Tissue samples from patients with CP were analyzed for matrix metalloproteinase (MMP) 10 expression.

RESULTS

In contrast to their relaF/F littermates, relaΔpanc displayed typical signs of CP after long-term stimulation with cerulein. Numerous macrophages and activated α-smooth muscle actin (SMA)-positive PSCs were detected. Additional inactivation of RelA/p65 in myeloid cells (relaΔpanc,Δmye) attenuated fibrosis. In vitro, RelA/p65-deficient, lipopolysaccharide (LPS)-stimulated macrophages degraded fibronectin in cocultured PSCs. Using gene expression analysis, MMP-10 was identified as a candidate for this process. Recombinant MMP-10 degraded fibronectin in LPS-stimulated PSCs. In tissue samples from patients with CP, MMP-10 was up-regulated in myeloid cells.

CONCLUSIONS

RelA/p65 functions in myeloid cells to promote pathogenesis of CP. In acinar cells, RelA/p65 protects against chronic inflammation, whereas myeloid RelA/p65 promotes fibrogenesis. In macrophage, MMP-10 functions as a RelA/p65-dependent, potentially antifibrogenic factor during progression of CP.

Pigment epithelium-derived factor regulates early pancreatic fibrotic responses and suppresses the profibrotic cytokine thrombospondin-1

Pigment epithelium-derived factor (PEDF) is important for maintaining the normal extracellular matrix. We hypothesized that the initiation of pancreatic fibrosis is dependent on the loss of PEDF. Pancreatic PEDF expression was assessed in wild-type mice fed either a control or ethanol diet using an intragastric feeding model. Pancreatitis responses were elicited with either a single episode or a repetitive cerulein-induced (50 μg/kg, 6 hourly i.p. injections) protocol in wild-type and PEDF-null mice. Quantitative real-time PCR and immunoblotting were performed to assess fibrogenic responses. In wild-type animals, PEDF expression increased with pancreatitis and was more pronounced in mice fed ethanol. Compared with wild-type mice, α-smooth muscle actin staining and expression levels of fibrogenic markers (eg, transforming growth factor-β1, platelet-derived growth factor, collagen I, and thrombospondin-1) were higher in PEDF-null mice at baseline. Sirius red staining revealed more fibrosis in PEDF-null versus wild-type pancreas 1 week after pancreatitis. Differences in tissue fibrosis resolved with longer recovery periods. PEDF overexpression suppressed thrombospondin-1 levels in vitro. Ethanol feeding and experimental pancreatitis increased PEDF expression in wild-type mice. PEDF-null mice, however, demonstrated enhanced early fibrotic responses compared with wild-type mice with pancreatitis. These findings indicate that PEDF acts as a compensatory antifibrotic cytokine in pancreatitis.

Chymotrypsin C mutations in chronic pancreatitis

Chronic pancreatitis is a persistent inflammatory disorder characterized by destruction of the pancreatic parenchyma, maldigestion, and chronic pain. Mutations in the chymotrypsin C (CTRC) gene encoding the digestive enzyme CTRC have been shown to increase the risk of chronic pancreatitis in European and Asian populations. Here, we review the biochemical properties and physiological functions of human CTRC, summarize the functional defects associated with CTRC mutations, and discuss mechanistic models that might explain the increased disease risk in carriers.

Oxalate nephropathy associated with chronic pancreatitis

BACKGROUND AND OBJECTIVES

Enteric overabsorption of oxalate may lead to hyperoxaluria and subsequent acute oxalate nephritis (AON). AON related to chronic pancreatitis is a rare and poorly described condition precluding early recognition and treatment.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We collected the clinical characteristics, treatment, and renal outcome of 12 patients with chronic pancreatitis-associated AON followed in four French renal units.

RESULTS

Before AON, mild to moderate chronic kidney disease was present in all patients, diabetes mellitus in eight (insulin [n = 6]; oral antidiabetic drugs [n = 2]), and known chronic pancreatitis in only eight. At presentation, pancreas imaging showed gland atrophy/heterogeneity, Wirsung duct dilation, calcification, or pseudocyst. Renal findings consisted of rapidly progressive renal failure with tubulointerstitial profile. Acute modification of glomerular filtration preceded the AON (i.e., diarrhea and diuretics). Increase in urinary oxalate excretion was found in all tested patients and hypocalcemia in nine (<1.5 mmol/L in four patients). Renal biopsy showed diffuse crystal deposits, highly suggestive of oxalate crystals, with tubular necrosis and interstitial inflammatory cell infiltrates. Treatment consisted of pancreatic enzyme supplementation, oral calcium intake, and an oxalate-free diet in all patients and renal replacement therapy in five patients. After a median follow-up of 7 months, three of 12 patients reached end-stage renal disease.

CONCLUSION

AON is an under-recognized severe crystal-induced renal disease with features of tubulointerstitial nephritis that may occur in patients with a long history of chronic pancreatitis or reveal the pancreatic disease. Extrinsic triggering factors should be prevented.