Mutation analysis of the cystic fibrosis and cationic trypsinogen genes in patients with alcohol-related pancreatitis

A high prevalence of genetic polymorphisms in idiopathic and alcohol-associated chronic pancreatitis patients in Ireland

BACKGROUND

Individual genetic architecture is considered central to susceptibility and progression of disease in chronic pancreatitis. The study aimed to evaluate the presence of common pancreatic gene mutations in a defined cohort of idiopathic and alcohol-induced chronic pancreatitis patients in Ireland.

METHODS

The study comprised patients with idiopathic and alcohol-induced chronic pancreatitis and historic controls. Variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, cationic trypsinogen (PRSS1) gene and serine protease inhibitor kazal type-1 (SPINK1) gene, were assessed by Taqman© genotyping assay.

RESULTS

Of n = 126 patients and n = 167 controls, mutations were detected in 23 (20%) and in 10 (6%) respectively (P < 0.001). The majority of mutations found were in the SPINK1 gene variant N34S (13%) which increased disease risk almost six-fold (OR 5.9). Neither CFTR severe mutation (F508del) (P = 0.649) nor mild variant (R117H) (P = 0.327) were over-represented amongst patients compared to control subjects. PRSS1 variants were not detected in either patient or control subjects.

CONCLUSION

There was a significant prevalence of chronic pancreatitis-associated gene mutations in this well-phenotyped cohort. In patients with alcohol-related or idiopathic chronic pancreatitis, the possibility of genetic mutations in the SPINK 1 gene should be considered as a contributing aetiology factor.

Concussion Pathophysiology and Injury Biomechanics

PURPOSE OF REVIEW

The concussion public health burden has increased alongside our knowledge of the pathophysiology of mild traumatic brain injury (mTBI). The purpose of this review is to summarize our current understanding of mTBI pathophysiology and biomechanics and how these underlying principles correlate with clinical manifestations of mTBI.

RECENT FINDINGS

Changes in post-mTBI glutamate and GABA concentrations seem to be region-specific and time-dependent. Genetic variability may predict recovery and symptom severity while gender differences appear to be associated with the neuroinflammatory response and neuroplasticity. Ongoing biomechanical research has shown a growing body of evidence in support of an "individual-specific threshold" for mTBI that varies based on individual intrinsic factors. The literature demonstrates a well-characterized timeframe for mTBI pathophysiologic changes in animal models while work in this area continues to grow in humans. Current human research shows that these underlying post-mTBI effects are multifactorial and may correlate with symptomatology and recovery. While wearable sensor technology has advanced biomechanical impact research, a definitive concussion threshold remains elusive.

Genetic susceptibility factors for alcohol-induced chronic pancreatitis

Chronic pancreatitis is a progressive inflammatory disease of the pancreas and frequently associated with immoderate alcohol consumption. Since only a small proportion of alcoholics eventually develop chronic pancreatitis genetic susceptibility factors have long been suspected to contribute to the pathogenesis of the disease. Smaller studies in ethnically defined populations have found that not only polymorphism in proteins involved in the metabolism of ethanol, such as Alcohol Dehydrogenase and Aldehyde Dehydrogenase, can confer a risk for developing chronic pancreatitis but also mutations that had previously been reported in association with idiopathic pancreatitis, such as SPINK1 mutations. In a much broader approach employing genome wide search strategies the NAPS study found that polymorphisms in the Trypsin locus (PRSS1 rs10273639), and the Claudin 2 locus (CLDN2-RIPPLY1-MORC4 locus rs7057398 and rs12688220) confer an increased risk of developing alcohol-induced pancreatitis. These results from North America have now been confirmed by a European consortium. In another genome wide approach polymorphisms in the genes encoding Fucosyltransferase 2 (FUT2) non-secretor status and blood group B were not only found in association with higher serum lipase levels in healthy volunteers but also to more than double the risk for developing alcohol-associated chronic pancreatitis. These novel genetic associations will allow to investigate the pathophysiological and biochemical basis of alcohol-induced chronic pancreatitis on a cellular level and in much more detail than previously possible.

Spectrum and distribution of CFTR gene mutations in asthma and chronic pancreatitis cases of North Indian population

BACKGROUND

Cystic fibrosis transmembrane conductance regulator (CFTR) gene accounts for an autosomal recessive condition called cystic fibrosis (CF). In the Indian subcontinent, CF and its related diseases are under-diagnosed by the medical community due to poor knowledge of the disease and its confounding diagnosis, and also due to poor medical facilities available for these patients, thus causing an increased infant mortality rate with a low life expectancy in general. The aim of the study was to document the spectrum and distribution of CFTR mutations in controls, asthma and chronic pancreatitis cases of North India.

METHODS

A total of 800 subjects including 400 controls, 250 asthma cases and150 chronic pancreatitis cases were analyzed for 6 mutations (F508del, G542X, G551D, R117H, W1282X, and S549N) and IVS8 Tn polymorphism.

RESULTS

Out of 800 subjects, 18% [asthma - 24% (n=250), CP - 29.33% (n=150) cases and controls - 9.3% (n=400)] were positive for heterozygous mutation, 0.8% of the (n=250) asthmatic cases (n=250) were homozygous for IVS8 T5 polymorphism while no subjects were found positive for W1282X mutation. T5 polymorphism was more common in asthmatic cases while F508del mutation in chronic pancreatitis cases. The carrier frequency of F508del, G542X, G551D, R117H, S549N and T5 was 0.015, 0.025, 0.02, 0.005, 0.005, and 0.022 respectively. The cumulative carrier frequency was 0.093.

CONCLUSION

CFTR mutations were underestimated in Indian population. The present study will serve in establishment of genetic screening and prenatal setup for Indian population.

Association of cystic fibrosis transmembrane conductance regulator gene variants with acute lung injury in African American children with pneumonia*

OBJECTIVES

The cystic fibrosis transmembrane conductance regulator regulates fluid balance in alveolar epithelial cells and appears to modulate the inflammatory response. To determine whether more severe lung injury in children who develop community-acquired pneumonia is associated with variations known to affect function in the gene coding for cystic fibrosis transmembrane conductance regulator.

DESIGN

A prospective cohort genetic association study of lung injury in children with community-acquired pneumonia.

SETTING

Three major tertiary care children's hospitals.

SUBJECTS

Caucasian and African American children with community-acquired pneumonia either evaluated in the emergency department or admitted to the hospital.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Caucasian and African American children with pneumonia were genotyped for the most common variants reported to affect cystic fibrosis transmembrane conductance regulator function, the p.508del mutation, the (TG)mTn variable repeat region, and the M470V polymorphism in the cystic fibrosis transmembrane conductance regulator gene. Genotypes and haplotypes were determined, and the association of high-risk alleles or high-risk haplotypes (defined as the presence of at least one variant known to decrease the level of functional cystic fibrosis transmembrane conductance regulator) with the need for mechanical ventilation or the development of acute lung injury was evaluated. Forty-two children in the Caucasian cohort (n = 304) required mechanical ventilation; 32 developed acute lung injury. Forty-three children in the African American cohort (n = 474) required mechanical ventilation; 29 developed acute lung injury. In African American children, high-risk (TG)mTn alleles known to result in decreased levels of functional cystic fibrosis transmembrane conductance regulator were associated with the need for mechanical ventilation (p = .0013) and the development of acute lung injury (p = .0061). Multivariable analysis demonstrated that high-risk (TG)mTn alleles were independently associated with mechanical ventilation (odds ratios = 3.19; 95% confidence interval, 1.63-6.26) and acute lung injury (odds ratios = 3.36; 95% confidence interval, 1.50-7.53) in African American children.

CONCLUSION

Genetic variation in cystic fibrosis transmembrane conductance regulator is associated with acute lung injury in African American children with community-acquired pneumonia.

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.

A novel exon duplication of the cystic fibrosis transmembrane conductance regulator in a patient presenting with adult-onset recurrent pancreatitis

Pancreatitis is a rare occurrence in patients with cystic fibrosis (CF) affecting 1.2% of all patients, but it can be the first presenting sign in approximately 15% of adults with pancreatic sufficiency and a milder CF phenotype. We report a case of a woman with recurrent pancreatitis who has one cystic fibrosis-causing mutation (G551D) and the first known description of a pathologic duplication of exon 19 of the CF transmembrane conductance regulator (CFTR). A 30-year-old white woman with 30 attacks of pancreatitis over a 5-year period starting at age 25 presented to the genetics department. She was found to have a mutation in the SPINK1 gene, IVS3+184T>A, and one cystic fibrosis-causing mutation (G551D) prompting full gene sequencing of the CFTR, revealing an additional duplication of exon 19. Sweat chloride testing was elevated at 97 and 106 mmol/L. Despite normal growth parameters and lung function, it is important to be aware of recurrent pancreatitis as a presenting sign of CF. Comprehensive CF gene analysis is necessary to detect a second CF-causing mutation that may put patients at risk for more severe symptoms of pancreatitis. There is a significant difference in the prevalence of heterozygote mutations between available testing methods.

Genetic risk for alcoholic chronic pancreatitis

In recent years many studies have examined the genetic predisposition to pancreatic diseases. Pancreatic disease of an alcoholic etiology was determined to be a multi-factorial disease, where environmental factors interact with the genetic profile of the individual. In this review we discuss the main results from studies examining the frequency of genetic mutations in alcoholic chronic pancreatitis.

The prevalence of cationic trypsinogen (PRSS1) and serine protease inhibitor, Kazal type 1 (SPINK1) gene mutations in Polish patients with alcoholic and idiopathic chronic pancreatitis

BACKGROUND

The main cause of chronic pancreatitis (CP) is excessive alcohol consumption. On the other hand, only 5-10% of heavy drinkers develop chronic pancreatitis. We have only limited information regarding the pathogenic mechanism by which alcohol leads to the disease. Mutations of the PRSS1 and SPINK 1 have been mostly implicated in hereditary and idiopathic CP, but their presence in other types of this disease have also been reported.

AIMS

The aim of the study was to determine the frequency of PRSS1 and SPINK1 mutations in patients with chronic alcoholic (ACP) and idiopathic pancreatitis (ICP) as well as to investigate their relation to the clinical course of the disease.

METHODS

The study included 33 ACP and 14 ICP patients as well 46 healthy subjects. The diagnosis of CP was based on clinical data, ultrasound, and computed tomography. After isolation of DNA from peripheral blood two trypsinogen mutations were detected N29I and R122H by allelo-specific amplification polymerase chain reaction (ASA-PCR) and by the PCR-restriction fragment length polymorphism (RFLP). Beside this N34S mutation of SPINK1 was analyzed by PCR restriction fragment length polymorphism (PCR-RFLP).

RESULTS

PRSS1 mutations have been detected in 11 (33%) patients with ACP. The frequency of the PRSS1 mutations was higher in patients with ACP than in controls (4.3%) (p < 0.001). The frequency of PRSS1 mutation was present in 21.4% of ICP patients, which was significantly higher (p < 0.05) than in controls. Overall, six (18%) SPINK1 mutations in ACP group have been detected. Among 14 patients with ICP, in four (28.6%) of them SPINK1 has been detected. The same mutations have also been found in three (6.5%) control subjects. The frequency of the N34S mutation was higher in patients with ICP than in the controls (p < 0.05), but the frequency of N34S mutation did not differ between ACP and the control group. No relations have been detected between PRSS1 and SPINK1 mutations presence and clinical course and complications of CP.

CONCLUSIONS

Those preliminary data suggest the high prevalence of SPINK1 and PRSS1 mutations in the Polish population, generally, as well as in CP patients. It may be speculated that those mutations contribute to the development of chronic pancreatitis, especially in patients with alcohol overindulgence.

Genetic factors in chronic pancreatitis; implications for diagnosis, management and prognosis

Chronic pancreatitis (CP) is a clinical situation with persisting inflammation leading to destruction of the pancreas ensuing endocrine and exocrine failure. There are 4 subtypes: hereditary, idiopathic, alcoholic and tropical pancreatitis. Genetic factors can explain a significant proportion of CP cases. The PRSS1 gene, encoding cationic trypsinogen, was found to be correlated with hereditary CP. This signalled the extensive search for other candidate genes within the trypsin pathway. Genes like SPINK1 and CTRC are associated with CP and should be considered as important contributing factors rather than causative. The search for candidate genes not part of the trypsin pathway has been less successful and the only gene consistently associated with CP is the Cystic Fibrosis Transmembrane Regulator. In this review we will discuss the various CP subtypes in relation to the respective genetic variants. This review will also address the implications of genetic testing in daily clinical practise.

Genetic mutations in a Spanish population with chronic pancreatitis

BACKGROUND/AIMS

Mutations in the PRSS1 and the SPINK1 genes have variably been associated with alcohol-related, idiopathic and hereditary chronic pancreatitis (CP). The aim of this study was to determine for the first time the significance of PRSS1, SPINK1 mutations and genetic variants of AAT in a group of Spanish patients with CP.

METHODS

104 consecutive patients with CP were included, as well as 84 healthy control subjects. The R122H and N29I mutations in the PRSS1 gene, the N34S mutation in the SPINK1 gene and PiS and PiZ mutations in the AAT gene were analyzed by RFLP-PCR methods.

RESULTS

No R122H mutation was found in the PRSS1 gene, and N29I mutation was detected in 7.7% of CP patients. A N29I mutation was observed in 3.9% of patients with alcohol-related pancreatitis (ACP). A total of 5.8% of CP patients were identified with the N34S mutation. Genotype MS, SS and MZ were detected in 18.3, 3.8 and 1.3% of CP patients, respectively.

CONCLUSION

The percentage of N29I mutations in ACP patients was higher than that reported in other studies, while the percentage of N34S and AAT mutations in ACP and idiopathic CP patients was similar.

CFTR polymorphisms in patients with alcoholic chronic pancreatitis

INTRODUCTION

Pancreas susceptibility to alcohol is variable and only 5-10% of chronic alcohol abusers develop chronic pancreatitis; the role of genetic factors in this process is unknown. The CFTR gene encodes a protein that acts on epithelial cells and plays a key role in normal exocrine pancreatic function.

METHODS

This study investigated the frequency of polymorphisms in intron 8 of the CFTR gene in patients with alcoholic chronic pancreatitis. Three groups of patients were studied: group A - 68 adult alcoholics with a diagnosis of chronic pancreatitis; group B - 68 adult alcoholics without pancreatic disease or liver cirrhosis and group C - 104 healthy nonalcoholic adults.

RESULTS

T5/T7 genotype was more frequent in group A (11.8%) than in group B (2.9%) (p = 0.0481), and there was no statistical difference when groups A and C (5.8%) were compared (p = 0.1317). The haplotype combination (TG)10-T7/(TG)11-T7 was more frequent in groups B (23.5%) and C (20.2%) than in group A (7.3%) (p = 0.0080 and 0.0162).

CONCLUSION

There are differences when these three groups are compared and individuals with T5/T7 genotype might have a greater risk of developing chronic pancreatitis when they become chronic alcoholics.

Polymorphisms of the MCP-1 and HSP70-2 genes in Korean patients with alcoholic chronic pancreatitis

Alcoholic chronic pancreatitis (ACP) develops in only a small number of alcoholics. Monocyte chemotactic protein-1 (MCP-1) and heat-shock protein 70-2 (HSP70-2) polymorphisms have been reported to be associated with the severity of acute pancreatitis. However, their role in pathogenesis of ACP has not been investigated. A genetic association study for susceptibility and severity was performed on 79 male Korean ACP patients and 82 male controls. MCP-1 and HSP70-2 genotypes were determined using a fluorescence polarization detection method. The genotypes and G allele frequencies were no different in patients and controls. However, MCP-1 G allele had an effect on the development of severe ACP, when its frequency was compared in mild to moderate and severe ACP (29.6 vs. 56.0%, P = 0.02). The MCP-1 and HSP70-2 polymorphisms do not play a major role in the development of ACP in Koreans. However, MCP-1 polymorphism may be associated with the severity of ACP.

Pathophysiology of alcoholic pancreatitis: an overview

Use of alcohol is a worldwide habit regardless of socio-economic background. Heavy alcohol consumption is a potential risk factor for induction of pancreatitis. The current review cites the updated literature on the alcohol metabolism, its effects on gastrointestinal and pancreatic function and in causing pancreatic injury, genetic predisposition of alcohol induced pancreatitis. Reports describing prospective mechanisms of action of alcohol activating the signal transduction pathways, induction of oxidative stress parameters through the development of animal models are being presented.

Germline mutations and gene polymorphism associated with human pancreatitis

A wide range of mutations and polymorphisms in genes that relate to pancreatic function seem to be involved in the development of pancreatitis. Some of these genetic alterations lead to disease phenotypes with unequivocal mendelian inheritance patterns, whereas others seem to act as modifier genes in conjunction with environ-mental or, as yet unidentified, genetic cofactors. This article reviews germline changes in the genes for trypsin, pancreatic secretory trypsin inhibitor, the cystic fibrosis conductance regulator, lipid metabolism proteins, inflammatory mediators for cytokines, and cathepsin B.

Mutation analysis of SPINK1 and CFTR gene in Korean patients with alcoholic chronic pancreatitis

Several genetic mutations have been reported to increase susceptibility to chronic pancreatitis. However, their roles in alcoholic chronic pancreatitis are controversial. We investigated the prevalence of SPINK1 N34S and new CFTR Q1352H mutations in alcoholic chronic pancreatitis in Korea. Forty-three patients with alcoholic chronic pancreatitis were enrolled and 35 healthy individuals served as controls. The SPINK1 N34S mutation was detected by the PCR-RFLP technique. The CFTR Q1352H mutation was examined with PCR direct sequencing. Mean age of chronic pancreatitis and control groups was 53.2 and 51.3 years, respectively. A SPINK1 N34S was detected as a heterozygote in one (2.4%) patient with alcoholic chronic pancreatitis and a heterozygote CFTR Q1352H was detected in one other patient. In the control population, neither SPINK1 nor CFTR mutation was detected. This study shows that SPINK1 N34S and CFTR Q1352H mutations are uncommon and do not play an important role in chronic alcoholic pancreatitis in Korea.

The impact of cystic fibrosis and PSTI/SPINK1 gene mutations on susceptibility to chronic pancreatitis

This article reviews current concepts regarding the pathobiology of cystic fibrosis pancreatic disease. It summarizes recent studies on the relationship between CFTR mutations and pancreatitis, and it reviews several unresolved issues in the field.

Reduced CFTR function and the pathobiology of idiopathic pancreatitis

Idiopathic chronic pancreatitis (ICP) is the leading cause of chronic pancreatitis in children and nonalcoholic adults. The risk of developing ICP is increased in individuals who have mutations of the cystic fibrosis gene (CFTR) and of a trypsin inhibitor gene (PSTI). In studies from the United States and France, the risk of ICP is increased about 40-fold by having two abnormal copies of the CFTR gene, about 14-fold by having the N34S PSTI mutation, and about 500-fold by having both. When ICP patients have two abnormal copies of the CFTR gene, there is also evidence of reduced residual CFTR protein function in extrapancreatic tissues based on clinical findings and nasal ion transport responses. Thus, pancreatitis risk is highest in individuals who have abnormalities in both the pancreatic ducts (CFTR) and acini (PSTI). These findings indicate that PSTI is a modifier gene for CFTR-related ICP and have implications for the diagnosis and pathogenesis of pancreatitis.

Alcoholic pancreatitis

Without doubt, alcohol consumption is one of the most important considerations in adults with acute or chronic pancreatitis. Understanding chronic pancreatitis as a complex disorder in which complimentary factors are required for recurrent acute and late chronic pancreatitis to develop in subsets of patients is critical for the early diagnosis and management of these individuals. Recent pathophysiological and genetic findings represent the beginning of major diagnostic and treatment breakthroughs that are likely to continue for the foreseeable future. The information provided in this article should provide the physician with a fresh perspective and remind the clinician of the importance of an accurate and complete history, and the need to document the actual alcohol consumption, pattern of drinking, and raise appropriate concerns if signs of alcoholism are detected. If alcohol-associated pancreatitis is detected, then limitation of pancreatic damage, limitation of progression, or preventative intervention should become the major concern.

The role of cystic fibrosis gene mutations in determining susceptibility to chronic pancreatitis

This article reviews current concepts regarding the pathobiology of cystic fibrosis pancreatic disease. It summarizes recent studies on the relationship between CFTR mutations and pancreatitis, and it reviews several unresolved issues in the field.

Pancreatitis in hispanic patients with cystic fibrosis carrying the R334W mutation

BACKGROUND & AIMS

Cystic fibrosis (CF) results from abnormal production of sticky mucus, which obstructs many organs. In most cases, the pancreas is severely compromised, but 10%-15% of patients with CF have pancreas sufficiency (PS) and are subject to develop pancreatitis. The aim of this study is to determine which specific genotypes lead to the development of pancreatitis in patients with CF.

METHODS

We used prospective data collected by the Cystic Fibrosis Foundation and performed a nested case-control study with all patients who reported at least 1 episode of pancreatitis constituting the cases. We used logistic regression to assess the association between pancreatitis and genotype and the Kaplan-Meier method to estimate the cumulative incidence of pancreatitis for selected genotypes.

RESULTS

Three hundred sixty-four of 17,871 genotyped patients with CF (2.0%) reported at least 1 episode of pancreatitis. Only 0.9% of 12,997 patients with genotypes generally associated with pancreas insufficiency reported pancreatitis against 11.9% of 868 patients carrying at least 1 mild CF mutation generally associated with PS. The greatest rate of pancreatitis (19.0%) was observed for patients carrying an R334W mutation: 48% of these 79 patients were Hispanic and 13 patients were living in Puerto Rico.

CONCLUSIONS

Of all patients with CF, those carrying an R334W mutation have the greatest risk for developing pancreatitis. This mutation is found mostly in Hispanic patients with CF living in Puerto Rico. There are no current data to determine whether asymptomatic carriers of the R334W mutation are at greater risk for developing pancreatitis or whether this mutation is frequent in Hispanics with idiopathic pancreatitis.

Different CFTR mutational spectrum in alcoholic and idiopathic chronic pancreatitis?

OBJECTIVE

Cystic fibrosis transmembrane conductance regulator (CFTR) mutations are responsible for cystic fibrosis (CF) and have been postulated as a predisposing risk factor to chronic pancreatitis (CP), but controversial results demand additional support. We have therefore investigated the role of the CFTR gene in a cohort of 68 CP patients.

METHODS

We have performed the CFTR gene analysis using 2 screening techniques. Fragments showing abnormal migration patterns were characterized by sequencing. Patients were classified in alcoholic (ACP) (n = 37) and idiopathic (ICP) (n = 31) chronic pancreatitis. Clinical features of CP and CF were evaluated.

RESULTS

Sixteen mutations/variants were identified in 27 patients (40%), most of them (35%) presenting a single CFTR mutant gene. The 1716G/A variant showed the highest frequency accounting for 22% in ICP and 5% in ACP, in contrast with other more common mutations such as F508del found in 8% of ACP and the 5T variant identified in 7% of patients. Acute pancreatitis, abdominal pain, tobacco, pancreatic calcifications, and pancreatic pseudocysts showed significant higher values in ACP than ICP patients. No significant differences were found between patients with and without CFTR mutations.

CONCLUSIONS

Apart from reinforcing previous findings our data highlight the increased susceptibility of CFTR heterozygous to developing CP. Heterozygosity, combined with other factors, places these individuals at greater risk.

A finger sweat chloride test for the detection of a high-risk group of chronic pancreatitis

OBJECTIVES

Mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene are associated with chronic pancreatitis in Caucasians. We developed a simple method for measuring finger sweat chloride concentration to test whether CFTR dysfunction underlies chronic pancreatitis in Japan where cystic fibrosis (CF) is rare.

METHODS

We studied 25 patients with chronic (21 alcoholic and 4 idiopathic) pancreatitis and 25 healthy volunteers. Sweat chloride concentrations were measured by a finger sweat chloride test. We analyzed DNA for 20 common CFTR mutations in Europeans, 9 CF-causing mutations in Japanese, and 2 polymorphic loci, a poly-T tract and (TG) repeats, at intron 8.

RESULTS

Thirteen patients (52%) had sweat chloride levels >60 mmol/L, a level consistent with CF, while only 4 (16%) healthy subjects exceeded this level. The 29 CF mutations and the 5T allele were detected in neither the patients nor controls. The (TG) 12 allele was common in both the patients (58%) and controls (48%). The (TG) 12/12 genotype was common in alcoholic pancreatitis (29%) compared with the (TG) 11/11 (10%). Patients with the (TG) 12/12 genotype had significantly higher sweat chloride concentrations than the controls.

CONCLUSION

CFTR dysfunction as evidenced by a finger sweat chloride test is present in about half of Japanese patients with chronic pancreatitis, suggesting that this test may be useful for detecting the high-risk group. A higher proportion of the (TG) 12 allele may be a genetic background for elevated sweat chloride concentrations in Japanese patients.

Analysis of tumor necrosis factor-alpha, transforming growth factor-beta 1, interleukin-10, and interferon-gamma polymorphisms in patients with alcoholic chronic pancreatitis

The pathophysiologic mechanisms underlying alcoholic chronic pancreatitis are poorly understood. Cytokines participate in the immunologic progression of acute and chronic pancreatitis and may play an important role in the development of pancreatic fibrosis. Functional polymorphisms in cytokine genes have been identified that alter cytokine production. The aims of the current investigation were to determine whether functional polymorphisms in the tumor necrosis factor-alpha (TNF-alpha) gene at positions -308 and -238; in the transforming growth factor-beta 1 (TGF-beta(1)) gene at positions -509, +869 (codon 10), and +915 (codon 25); in the interleukin-10 (IL-10) gene at position -1082; and in the intron 1 of the interferon-gamma (IFN-gamma) gene at position +874 are associated with alcoholic chronic pancreatitis. We investigated 42 patients with alcoholic chronic pancreatitis. We studied 94 control subjects for the TNF-alpha polymorphisms and 73 control subjects for the remaining polymorphisms. Mutation analysis was performed by direct DNA sequencing or by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). The genotype frequencies were similar between patients and control subjects for all investigated cytokine polymorphisms (P>.05). We did not find an association between the different genotypes and the clinical course of the disease. Therefore, we assume that these genetic variants do not play a dominant role in alcoholic chronic pancreatitis.

Genetic predisposition to alcoholic chronic pancreatitis

The mechanisms leading to alcoholic chronic pancreatitis in humans have remained elusive. Numerous questions surround the apparent random nature of the disease in which 1 person is hit with alcoholic chronic pancreatitis while the next is spared. Why do fewer than 10% of chronic, heavy alcohol users ever develop pancreatitis, while others develop alcoholic liver disease, neuropathy, or other alcohol-associated problems? Why do laboratory animals, fed large amounts of alcohol for prolonged periods of time, fail to develop typical chronic pancreatitis? Why are heavy alcohol users from a black African background more likely to develop pancreatic diseases than Caucasians, whereas the opposite is true for the development of liver disease? The answers underlying these questions appear to reflect the differences in underlying genetic susceptibility, environmental exposure, and the interaction between these factors. Thus, even cases of "typical" alcoholic chronic pancreatitis or other forms of pancreatitis appear to be complex diseases. Recently, several genetic mutations have been identified that increase the susceptibility to pancreatitis. However, the major common gene mutations in CFTR, PRSS1, and SPINK1 only slightly increase the risk of alcoholic chronic pancreatitis. New genetic, environmental, and triggering factors must be considered to gain further insight into the mechanisms leading to alcoholic chronic pancreatitis so that strategies for treatment and prevention can be developed.

Chronic pancreatitis

PURPOSE OF REVIEW

We are beginning to better understand the causes of chronic pancreatitis. This knowledge will hopefully lead to better diagnosis and treatment and abandonment of ill-conceived treatments. This review highlights contributions that moved the field toward these goals in the past year.

RECENT FINDINGS

Small steps have been made toward a better understanding of the molecular basis, particularly genetic causes, of the forms of chronic pancreatitis. Investigation of the role of stellate cells, an essential component of the fibrosis of chronic pancreatitis, has led to the finding that lovastatin inhibits stellate cell activation and could surface as a novel treatment of chronic pancreatitis. The clinical description of autoimmune pancreatitis has led to the realization that steroids are effective treatment for this form of chronic pancreatitis. Other treatments such as extracorporeal shock wave lithotripsy and endoscopic treatments have not been proved, because no controlled studies support these treatments over other treatments. The diagnosis of chronic pancreatitis may be enhanced by the new imaging technique of electronic pancreatoscopy whereby a 2.1-mm diameter scope can be advanced into the pancreatic duct through a duodenoscope. However, the data are too preliminary at this time to advocate this imaging procedure. A potential new endoscopic pancreatic function test may lead to more widespread use of function testing, but this test is not perfected and also cannot be advised for use at present.

SUMMARY

Ongoing basic and clinical research this past year has further characterized the genetic, molecular, and clinical aspects of chronic pancreatitis: efforts that may translate into novel therapies, once well-designed, controlled studies have been performed.

Mutation analysis of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, the cationic trypsinogen (PRSS1) gene, and the serine protease inhibitor, Kazal type 1 (SPINK1) gene in patients with alcoholic chronic pancreatitis

Susceptibility to alcoholic chronic pancreatitis (ACP) could be genetically determined. Mutations in cationic trypsinogen (PRSS1), cystic fibrosis transmembrane conductance regulator (CFTR), and serine protease inhibitor, Kazal type 1 (SPINK1) genes have been variably associated with both the hereditary and the idiopathic form of chronic pancreatitis (CP). Our aim was to analyze the three genes in ACP patients. Mutational screening was performed in 45 unrelated ACP patients and 34 patients with alcoholic liver disease (ALD). No mutation of PRSS1 was found in ACP and ALD patients. Three mutations of CFTR were detected in four ACP patients with a prevalence (8.9%) not significantly different from that observed (3.0%) in ALD patients and from that expected (3.2%) in our geographical area. Neither compound heterozygotes for CFTR nor trans-heterozygotes for CFTR/SPINK1 were found. One ACP patient (2.2%) was found to carry the most common mutation (N34S) of SPINK1 compared to none of the ALD patients (P=NS). In five other patients (two with ACP and three with ALD) other rare variants, including P55S, were found. In contrast with the hereditary and the idiopathic forms of CP, in which mutations of PRSS1, CFTR, and SPINK1 genes may occur, ACP is still a "gene(s)-orphan" disease. The supposed genetic susceptibility to ACP relies on other yet unknown gene(s) which could affect the alcohol metabolism or modulate the pancreatic inflammatory response to alcohol abuse.

Genetic polymorphisms in alcoholic pancreatitis

Chronic, excessive alcohol consumption is clearly associated with acute and chronic pancreatitis. However, both clinical and laboratory studies have demonstrated that alcohol consumption alone does not directly cause pancreatitis. Growing evidence suggests that environmental and possibly genetic cofactors must also be present before the mechanisms protecting the pancreas from pancreatitis are circumvented and pancreatitis develops. The discovery that mutations in the cationic trypsinogen gene (R122H, N29I) predisposed to acute and chronic pancreatitis focused attention on possible genetic predispositions. Mutations in the cationic trypsinogen gene, however, are rarely associated with alcoholic chronic pancreatitis. Mutations in the SPINK1 gene (e.g. N34S) provide a threefold increased risk, and cystic fibrosis transmembrane conductance regulator (CFTR) mutations continue to be investigated. However, the major cofactor associated with alcoholic chronic pancreatitis is yet to be identified.

Genetic factors in pancreatitis

A number of genetic mutations have recently been identified that appear to be important in the development of pancreatitis. Point mutations in the cationic trypsinogen gene are capable of initiating pancreatitis. These mutations also provide important insights into the pathophysiology of acute pancreatitis and into potential connections between acute and chronic pancreatitis. Mutations in the genes encoding for the pancreatic secretory trypsin inhibitor and the cystic fibrosis transmembrane conductance regulator more likely work in concert with other genes and environmental factors in affecting disease susceptibility. Although the subject so far has received only a limited amount of study, genetic polymorphisms in a wide range of genes relating to pancreatic function and to regulation of inflammation are likely to play major roles in determining each individual's susceptibility to developing pancreatitis, and its severity if it does develop.

Cystic fibrosis and related diseases of the pancreas

The discovery of the gene for cystic fibrosis (CF), the cystic fibrosis transmembrane conductance regulator (CFTR), brought about a new era in the study of this disease. Identification of the molecular target has yielded a flood of data that add to our understanding of the pathogenesis, diagnosis and treatment of CF. The CFTR protein is a cAMP-regulated Cl(-) channel with multiple functions in epithelial cells. In the exocrine pancreas the CFTR plays a key role in the apical Cl(-), HCO(3)(-), and water transport in duct cells. The severe loss of functions, caused by mutations of the CFTR gene, leads to pathological lesions of the pancreas. Over 1200 CFTR mutations and polymorphisms have been identified and their diversity may explain the high level of heterogeneity in the CF phenotype. Mutation analyses of the CFTR gene have revealed a spectrum of CFTR-related diseases that do not fit the classical CF picture but are associated with dysfunction of CFTR, such as chronic pancreatitis.

Improved detection of CFTR mutations in Southern California Hispanic CF patients

Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis (CF), a common autosomal recessive disease in Caucasians. The broad mutation spectrum varies among different patient groups. Current molecular diagnoses are designed to detect 80-97% of CF chromosomes in Caucasians and Ashkenazi Jews but have a much lower detection rate in Hispanic CF patients. Grebe et al. [1994] reported a 58% detection rate in Hispanic patients. Since then, there has been no large-scale, complete mutational analysis of Hispanic CF patients. In this study, the mutations in 62 Hispanic patients from southern California were investigated. The entire coding and flanking intronic regions of the CFTR gene were analyzed by temporal temperature gradient gel electrophoresis (TTGE) followed by sequencing to identify the mutations. Eleven novel mutations were discovered in this patient group: 3876delA, 406-1G>A, 935delA, 663delT, 3271delGG, 2105-2117del13insAGAAA, 3199del6, Q179K, 2108delA, 3171delC, and 3500-2A>T. Among the mutations, seven were out-of-frame insertions and deletions that result in truncated proteins, two were splice-site mutations, one was an in-frame 6 bp deletion, and one was a missense mutation that involved the non-conservative change of glutamine-179 to lysine. All patients presented severe classical clinical course with pancreatic insufficiency and poor growth, consistent with the nature of truncation mutation. The results indicate that TTGE screening following the analysis of recurrent mutations will substantially improve the mutation detection rate for Hispanic CF patients from southern California.

Cystic fibrosis

Although mutation detection rates have not universally reached the 95% detection level recommended by the American Society of Human Genetics and are not likely to exceed 90% for many populations in the foreseeable future, CF carrier screening will probably be offered routinely in the near future. Although CF carrier information will be of benefit to some individuals and couples, the inability of conventional prenatal diagnosis to provide definitive diagnostic outcomes to some couples, specifically those couples in which only one partner has a detectable mutation, will make for considerable anguish and concern for some. Because genetic screening and counseling is meant to provide information and alleviate concerns and fears, the potential for CF screening to result in such a contradictory effect is of a continuing concern to those who provide obstetric and genetic services. In a National Institute of Health-sponsored workshop, Menutti and colleagues recommended that those populations to which carrier screening should be offered might include individuals and couples in high-risk groups (e.g., Ashkenazi Jews, central or northern Europeans, one partner with CF, and individuals with a family history of CF) who seek preconception counseling, infertility care, or prenatal care. The workshop participants concluded, however, that before screening can be offered systematically to these individuals or couples, practice guidelines, educational materials for providers and patients, informed-consent protocols, and laboratory standards for testing must be developed. Further advances in DNA and protein analytic capabilities, such as microchip analytic systems and protein truncation assays, may make CF screening and diagnosis more accurate and less likely to result in equivocal outcomes. In addition, it is hoped that continuing improvements in CF therapies will increase the life expectancy and improve the quality of life for individuals affected with CF. Expanding our current knowledge of genotype-phenotype correlations will not only allow us better to predict clinical outcomes but also may improve our treatments for individuals with CF because more targeted therapies may be developed for CF caused by specific mutations. Nonetheless, educational and counseling issues will, for the foreseeable future, remain of critical importance to ensure appropriate clinical care to low- and high-risk individuals.

Mutational screening of the cationic trypsinogen gene in a large cohort of subjects with idiopathic chronic pancreatitis

Several missense mutations, including R122H, N29I, K23R, A16V and D22G, in the cationic trypsinogen gene (PRSS1), have been associated with certain forms of hereditary pancreatitis (HP). Their occurrence in the idiopathic chronic pancreatitis (ICP) and whether novel mutations could be identified in PRSS1 remain to be further evaluated. These were addressed by the mutational screening of the entire coding sequence and the intronic/exonic boundaries of the PRSS1 gene in 221 ICP subjects, using a previously established denaturing gradient gel electrophoresis technique. Among the known PRSS1 mutations, only the R122H was detected in a single subject and the A16V in two subjects in the cohort, strengthening that HP-associated PRSS1 mutations are rare in ICP. Additional missense mutations, including P36R, E79K, G83E, K92N and V123M, were identified once separately. By analogy with the known PRSS1 mutations, predisposition to pancreatitis by some of them, particularly the V123M autolysis cleavage site mutation, is suspected. Functional analysis is expected to clarify their possible medical consequences.