Relation between mutations of the cystic fibrosis gene and idiopathic pancreatitis

Diagnostic yield of repeat genetic testing in idiopathic chronic pancreatitis

Genetic testing is performed for unexplained pancreatitis. The aim of this study was to evaluate the diagnostic value of repeating genetic testing in idiopathic pancreatitis when new predisposing genes are identified. We investigated 330 patients who were initially screened for PRSS1, SPINK1 and CFTR genes. A new analysis was performed by Next-Generation Sequencing (NGS) for PRSS1, SPINK1, CFTR, CTRC, CASR, CPA1, TRPV6 genes and the CEL-HYB1 allele in clinical practice, and patients were included in our cohort study. Additional rare variants were identified in 7.3 % of the patients. Screening for new pancreatitis genes is recommended when initial screening is limited. Routine use of NGS is a useful diagnostic tool in these cases.

Surgical and Endoscopic Intervention for Chronic Pancreatitis in Children: The Kings College Hospital Experience

Paediatric chronic pancreatitis (CP) is a rare and debilitating pathology that often requires invasive diagnostics and therapeutic interventions either to address a primary cause such as a pancreaticobiliary malunion or to deal with secondary complications such as chronic pain. Endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasound (EUS) are two endoscopic modalities that have an established diagnostic role in paediatric CP, and their therapeutic utilisation is increasing in popularity. Surgical decompression of the obstructed and dilated pancreatic duct plays a role in alleviating pancreatic duct hypertension, a common association in CP. Surgery equally has a role in certain anatomical abnormalities of the pancreaticobiliary draining system, or occasionally in some CP complications such as drainage of a symptomatic pancreatic pseudocyst.

Immune response mechanisms in acute and chronic pancreatitis: strategies for therapeutic intervention

Acute pancreatitis (AP) is one of the most common inflammatory diseases of the gastrointestinal tract and a steady rising diagnosis for inpatient hospitalization. About one in four patients, who experience an episode of AP, will develop chronic pancreatitis (CP) over time. While the initiating causes of pancreatitis can be complex, they consistently elicit an immune response that significantly determines the severity and course of the disease. Overall, AP is associated with a significant mortality rate of 1-5%, which is caused by either an excessive pro-inflammation, or a strong compensatory inhibition of bacterial defense mechanisms which lead to a severe necrotizing form of pancreatitis. At the time-point of hospitalization the already initiated immune response is the only promising common therapeutic target to treat or prevent a severe disease course. However, the complexity of the immune response requires fine-balanced therapeutic intervention which in addition is limited by the fact that a significant proportion of patients is in danger of development or progress to recurrent and chronic disease. Based on the recent literature we survey the disease-relevant immune mechanisms and evaluate appropriate and promising therapeutic targets for the treatment of acute and chronic pancreatitis.

Classification of PRSS1 variants responsible for chronic pancreatitis: An expert perspective from the Franco-Chinese GREPAN study group

BACKGROUND

PRSS1 was the first reported chronic pancreatitis (CP) gene. The existence of both gain-of-function (GoF) and gain-of-proteotoxicity (GoP) pathological PRSS1 variants, together with the fact that PRSS1 variants have been identified in CP subtypes spanning the range from monogenic to multifactorial, has made the classification of PRSS1 variants very challenging.

METHODS

All currently reported PRSS1 variants (derived primarily from two databases) were manually reviewed with respect to their clinical genetics, functional analysis and population allele frequency. They were classified by variant type and pathological mechanism within the framework of our recently proposed ACMG/AMP guidelines-based seven-category system.

RESULTS

The total number of distinct germline PRSS1 variants included for analysis was 100, comprising 3 copy number variants (CNVs), 12 5' and 3' variants, 19 intronic variants, 5 nonsense variants, 1 frameshift deletion variant, 6 synonymous variants, 1 in-frame duplication, 3 gene conversions and 50 missense variants. Based upon a combination of clinical genetic and functional analysis, population data and in silico analysis, we classified 26 variants (all 3 CNVs, the in-frame duplication, all 3 gene conversions and 19 missense) as "pathogenic", 3 variants (missense) as "likely pathogenic", 5 variants (four missense and one promoter) as "predisposing", 13 variants (all missense) as "unknown significance", 2 variants (missense) as "likely benign", and all remaining 51 variants as "benign".

CONCLUSIONS

We describe an expert classification of the 100 PRSS1 variants reported to date. The results have immediate implications for reclassifying many ClinVar-registered PRSS1 variants as well as providing optimal guidelines/standards for reporting PRSS1 variants.

Variability of Clinical Presentation in Patients Heterozygous for the F508del Cystic Fibrosis Variant: A Series of Three Cases and a Review of the Literature

Cystic fibrosis (CF) is a genetic disease that affects the lung, pancreas, and other organs caused by the presence of biallelic CF-causing variants in the cystic fibrosis conductance regular gene (CFTR). CFTR variants can also be found in CFTR-related disorders (CFTR-RD), which present milder symptoms. Increasing access to next-generation sequencing has demonstrated that both CF and CFTR-RD have a broader array of genotypes than formerly thought. Here we present three patients who carry the most common CFTR pathogenic variant - F508del - but express a wide array of phenotypes. These cases open discussion on the role of concurrent variants in CFTR, the importance of early diagnosis and treatment, and the contribution of lifestyle factors in CF and CFTR-RD presentation.

The Coexistence of TRPV6 Variants With Other Pancreatitis-Associated Genes Affects Pediatric-Onset Pancreatitis

OBJECTIVES

Recently, a genetic risk for chronic pancreatitis (CP) was found to be conferred by pathogenic variants in the transient receptor potential cation channel, subfamily V, member 6 ( TRPV6 ). Interestingly, 20%-57% of patients with functionally defective TRPV6 variants have other susceptibility genes such as cationic trypsinogen, serine protease inhibitor Kazal type 1, chymotrypsin C, cystic fibrosis transmembrane conductance regulator, and carboxypeptidase A1. In this study, we focused on pediatric patients with acute recurrent pancreatitis or CP with at least 1 variant in these 5 genes and investigated the presence of coexisting TRPV6 mutations.

METHODS

Ninety Japanese pediatric patients (median age at first onset, 8.0 years) who had at least 1 variant of these 5 genes were enrolled in this study. DNA samples were extracted for analysis from peripheral blood leukocytes. Coding regions of TRPV6 were screened by Sanger sequencing.

RESULTS

Regardless of functional defects or non-defects in TRPV6 variants, 14 of the 90 patients (15.6%) were trans-heterozygous for TRPV6 variants [p.A18S (n = 3), p.C197R (n = 3), p.I223T (n = 3), p.D324N (n = 4), p.M418V (n = 3), p.V540F (n = 1), p.A606T (n = 1), and p.M721T (n = 3)] and the 5 susceptibility genes noted above. Of these variants, p.D324N, p.V540F, and p.A606T are associated with pancreatitis. Three patients had the ancestral haplotype [p.C197R + p.M418V + p.M721T].

CONCLUSIONS

Overall, 4 of 90 patients (4.4%) had the coexistence of clearly pathogenic TRPV6 variants with pancreatitis-associated variants. The cumulative accumulation of these genetic factors may contribute to the development of pancreatitis at a young age.

A rare PRSS1 p.S127C mutation is associated with chronic pancreatitis and causes misfolding-induced ER-stress

BACKGROUND

/Objectives: Sequence variants in several genes have been identified as being associated with an increased inherited risk to develop chronic pancreatitis (CP). In a genetic survey of a CP patient we identified in the PRSS1gene a new c.380C > G sequence variation, giving rise to a non-synonymous p.S127C mutation. Functional studies were performed to analyze the associated pathophysiology of the variant.

METHODS

Following generation of an expression vector for the new PRSS1 variant we compared its expression, secretion and catalytic activity with already known PRSS1 risk variants in HEK 293T cells. The intracellular protein accumulation and induction of endoplasmic reticulum (ER)-stress was analyzed.

RESULTS

Prediction tool analysis indicated a probably deleterious effect of the p.S127C variant on protein function which was confirmed by detection of a secretion defect in HEK293T cells leading to intracellular protein accumulation. While protein misfolding was associated with reduced trypsin activity, the increased expression of BIP and presence of spliced XBP1 indicated that the p.S127C variant induces ER stress and activates the UPR signaling pathway.

CONCLUSIONS

The disease mechanism of the PRSS1 p.S127C variant involves defective protein secretion and the induction of ER-stress due to accumulation of presumably misfolded trypsinogen within the ER. The new variant should be considered disease-causing with an incomplete penetrance. Our results confirm that in addition to dysregulated trypsin-activity or reduced fluid secretion, ER-stress induction is an important trigger for acinar cell damage and the development of recurrent or chronic pancreatic inflammation.

Between early and established chronic pancreatitis: A proposal of "acinar-ductal hybrid mechanism"

BACKGROUND/OBJECTIVES

The recently proposed "new mechanistic definition of chronic pancreatitis (CP)" categorized early CP as a reversible condition. However, there is no clear explanation regarding the pathological condition of early CP, the reason for the development of the disease in only a small portion of the patients with risk factors, and the mechanism for transition from a reversible pathological condition to an irreversible one.

METHODS

Based on the available information, a mechanism that could provide answers to the queries associated with CP was proposed.

RESULTS

Acinar-ductal coordination is very important for the physiological secretion of pancreatic juice. Inflammation originating from acinar cells undermines the function of proximal ducts and leads to a vicious cycle of sustained inflammation by increasing the viscosity and decreasing the alkalinity of pancreatic juice. Persistent elevation of ductal pressure due to stagnation of pancreatic juice caused by protein plugs, stones, or fibrous scar of ducts converts the reversible pathological condition of early CP to an irreversible one. Diagnostic criteria for early CP proposed by Japanese researchers have enabled to the recognition of patients showing a progression from early to established CP. However, most patients diagnosed with early CP do not experience progression of the disease, suggesting the inadequate specificity of the criteria.

CONCLUSION

The "acinar-ductal hybrid mechanism" may explain the pathological condition and progression of early CP. To diagnose early CP more accurately, it is essential to discover specific biomarkers that can discriminate "early CP" from "acute pancreatitis (AP)/recurrent acute pancreatitis (RAP)" and "established CP." Therapeutic intervention in clinical practices through various new approaches is expected to improve the prognosis of patients with CP.

Bicarbonate defective CFTR variants increase risk for chronic pancreatitis: A meta-analysis

INTRODUCTION

Cystic fibrosis transmembrane conductance regulator (CFTR) plays a central role in pancreatic ductal fluid secretion by mediating Cl- and HCO3- ion transport across the apical membrane. Severe CFTR mutations that diminish chloride conductance cause cystic fibrosis (CF) if both alleles are affected, whereas heterozygous carrier status increases risk for chronic pancreatitis (CP). It has been proposed that a subset of CFTR variants characterized by a selective bicarbonate conductance defect (CFTRBD) may be associated with CP but not CF. However, a rigorous genetic analysis of the presumed association has been lacking.

AIMS

To investigate the role of heterozygous CFTRBD variants in CP by meta-analysis of published case-control studies.

MATERIALS AND METHODS

A systematic search was conducted in the MEDLINE, Embase, Scopus, and CENTRAL databases for published studies that reported the CFTRBD variants p.R74Q, p.R75Q, p.R117H, p.R170H, p.L967S, p.L997F, p.D1152H, p.S1235R, and p.D1270N in CP patients and controls.

RESULTS

Twenty-two studies were eligible for quantitative synthesis. Combined analysis of the 9 CFTRBD variants indicated enrichment in CP patients versus controls (OR = 2.31, 95% CI = 1.17-4.56). Individual analysis of CFTRBD variants revealed no association of p.R75Q with CP (OR = 1.12, 95% CI = 0.89-1.40), whereas variants p.R117H and p.L967S were significantly overrepresented in cases relative to controls (OR = 3.16, 95% CI = 1.94-5.14, and OR = 3.88, 95% CI = 1.32-11.47, respectively). The remaining 6 low-frequency variants gave inconclusive results when analyzed individually, however, their pooled analysis indicated association with CP (OR = 2.08, 95% CI = 1.38-3.13).

CONCLUSION

Heterozygous CFTRBD variants, with the exception of p.R75Q, increase CP risk about 2-4-fold.

Expanding ACMG variant classification guidelines into a general framework

BACKGROUND

The American College of Medical Genetics and Genomics (ACMG)-recommended five variant classification categories (pathogenic, likely pathogenic, uncertain significance, likely benign, and benign) have been widely used in medical genetics. However, these guidelines are fundamentally constrained in practice owing to their focus upon Mendelian disease genes and their dichotomous classification of variants as being either causal or not. Herein, we attempt to expand the ACMG guidelines into a general variant classification framework that takes into account not only the continuum of clinical phenotypes, but also the continuum of the variants' genetic effects, and the different pathological roles of the implicated genes.

MAIN BODY

As a disease model, we employed chronic pancreatitis (CP), which manifests clinically as a spectrum from monogenic to multifactorial. Bearing in mind that any general conceptual proposal should be based upon sound data, we focused our analysis on the four most extensively studied CP genes, PRSS1, CFTR, SPINK1 and CTRC. Based upon several cross-gene and cross-variant comparisons, we first assigned the different genes to two distinct categories in terms of disease causation: CP-causing (PRSS1 and SPINK1) and CP-predisposing (CFTR and CTRC). We then employed two new classificatory categories, "predisposing" and "likely predisposing", to replace ACMG's "pathogenic" and "likely pathogenic" categories in the context of CP-predisposing genes, thereby classifying all pathologically relevant variants in these genes as "predisposing". In the case of CP-causing genes, the two new classificatory categories served to extend the five ACMG categories whilst two thresholds (allele frequency and functional) were introduced to discriminate "pathogenic" from "predisposing" variants.

CONCLUSION

Employing CP as a disease model, we expand ACMG guidelines into a five-category classification system (predisposing, likely predisposing, uncertain significance, likely benign, and benign) and a seven-category classification system (pathogenic, likely pathogenic, predisposing, likely predisposing, uncertain significance, likely benign, and benign) in the context of disease-predisposing and disease-causing genes, respectively. Taken together, the two systems constitute a general variant classification framework that, in principle, should span the entire spectrum of variants in any disease-related gene. The maximal compliance of our five-category and seven-category classification systems with the ACMG guidelines ought to facilitate their practical application.

C FTR variants are associated with chronic bronchitis in smokers

INTRODUCTION

Loss-of-function variants in both copies of the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis (CF); however, there is evidence that reduction in CFTR function due to the presence of one deleterious variant can have clinical consequences. Here, we hypothesise that CFTR variants in individuals with a history of smoking are associated with chronic obstructive pulmonary disease (COPD) and related phenotypes.

METHODS

Whole-genome sequencing was performed through the National Heart, Lung, and Blood Institute TOPMed (TransOmics in Precision Medicine) programme in 8597 subjects from the COPDGene (Genetic Epidemiology of COPD) study, an observational study of current and former smokers. We extracted clinically annotated CFTR variants and performed single-variant and variant-set testing for COPD and related phenotypes. Replication was performed in 2118 subjects from the ECLIPSE (Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints) study.

RESULTS

We identified 301 coding variants within the CFTR gene boundary: 147 of these have been reported in individuals with CF, including 36 CF-causing variants. We found that CF-causing variants were associated with chronic bronchitis in variant-set testing in COPDGene (one-sided p=0.0025; OR 1.53) and in meta-analysis of COPDGene and ECLIPSE (one-sided p=0.0060; OR 1.52). Single-variant testing revealed that the F508del variant was associated with chronic bronchitis in COPDGene (one-sided p=0.015; OR 1.47). In addition, we identified 32 subjects with two or more CFTR variants on separate alleles and these subjects were enriched for COPD cases (p=0.010).

CONCLUSIONS

Cigarette smokers who carry one deleterious CFTR variant have higher rates of chronic bronchitis, while presence of two CFTR variants may be associated with COPD. These results indicate that genetically mediated reduction in CFTR function contributes to COPD related phenotypes, in particular chronic bronchitis.

Current clinical opinion on CFTR dysfunction and patient risk of pancreatitis: diagnostic and therapeutic considerations

INTRODUCTION

Cystic fibrosis transmembrane conductance regulator (CFTR)-mediated chloride and bicarbonate secretion is integral to the pancreas' ability to produce the alkaline pancreatic juice required for proper activation of enzymes for digestion. Disruption in this process increases the risk for pancreatitis.

AREAS COVERED

Using original basic and clinical research, as well as clinical case reports and recent reviews indexed in PubMed, we discuss why patients with CFTR dysfunction are at risk for pancreatitis. We also discuss diagnostic modalities for assessing CFTR function, as well as new therapeutic advancements and the impact these are having on pancreatic function, pancreatitis in particular.

EXPERT OPINION

CFTR-related pancreatitis occurs in the presence of monallelic or biallelic mutations and/or from toxin-mediated channel disruption. Research-based CFTR diagnostics have been expanded, yet all current methods rely on measuring CFTR chloride transport in non-pancreatic cells/tissue. Newer CFTR-directed therapies ('CFTR modulators') are both improving pancreatitis (pancreatic-sufficient CF patients) and increasing the risk for pancreatitis (previously pancreatic-insufficient CF patients). Our experiences with these drugs are enlightening us on how CFTR modulation can affect pancreatitis risk across a wide spectrum of pancreatic disease, and represents an opportunity for therapeutic relief from pancreatitis in those without CF, but who suffer from CFTR-related pancreatitis.

Cystic fibrosis transmembrane conductance regulator function in patients with chronic pancreatitis

BACKGROUND

Pathogenesis of chronic pancreatitis (CP) is still not entirely understood with many patients probably having more than 1 underlying etiology. Besides toxic-metabolic factors, genetics contribute to disease development. Mutations in cystic fibrosis transmembrane conductance regulator (CFTR) are shown to increase risk for CP. Activity of CFTR can easily be accessed in vivo by measurement of nasal potential difference (PD).

METHODS

We compared in this monocentric study 17 CP patients from the outpatient unit of our university hospital with 30 healthy controls regarding nasal PDs by using a superfusion protocol. Additionally, demographic and lifestyle data of all persons were recorded.

RESULTS

Seventeen patients (12% female, median age 48 years) with CP and 30 healthy volunteers (47% female, 25 years) were included in the study. Patients with CP had a significant higher proportion of CFTR dysfunction (P = .04). Furthermore, demographics differed between the 2 groups with CP patients being older (P < .001). There were differences in daily alcohol consumption (P = .001) and smoking habits (smokers vs nonsmokers: P = .01, pack years: P = .002).

CONCLUSIONS

PD measurement is an easily accessible way to show CFTR dysfunction as an etiological factor of CP. Cigarette smoking might impair CFTR function and therefore be 1 preventable cause of CP evolution.

Genetic Evaluation of Pancreatitis

Hereditary pancreatitis (HP) is a rare inherited chronic pancreatitis (CP) with strong genetic associations, with estimated prevalence ranging from 0.3 to 0.57 per 100,000 across Europe, North America, and East Asia. Apart from the most well-described genetic variants are PRSS1, SPINK1, and CFTR, many other genes, such as CTRC, CPA1, and CLDN2 and CEL have been found to associate with HP, typically in one of the 3 main mechanisms such as altered trypsin activity, pancreatic ductal cell secretion, and calcium channel regulation. The current mainstay of management for patients with HP comprises genetic testing for eligible individuals and families, alcohol and tobacco cessation avoidance, pain control, and judicious screening for complications, including exocrine and endocrine insufficiency and pancreatic cancer.

Impact of genetic testing and smoking on the distribution of risk factors in patients with recurrent acute and chronic pancreatitis

OBJECTIVE

The aim of the present study is to assess the impact of smoking dose and duration on the distribution of risk factor(s) in patients with RAP and CP, and the impact of genetic testing on the distribution of risk factor(s) in patients with idiopathic RAP and CP.

METHODS

All adult patients with RAP and CP referred to a multidisciplinary pancreatitis clinic between 2010 and 2017 were evaluated. Risk factors included alcohol and smoking, hypertriglyceridemia, biliary, and other etiologies. Genetic testing was only pursued in patients with idiopathic RAP or CP.

RESULTS

Among the 1770 patients evaluated, 167 had RAP and 303 had CP. After genetic testing and smoking, the most common risk factors for RAP and CP were pathogenic variant(s) (23%) and the combination of alcohol and smoking (23%), respectively. Genetic testing and smoking assessment decreased the proportion of patients with alcoholic RAP from 17% to 5%, alcoholic CP from 33% to 10%, idiopathic RAP from 49% to 12%, and idiopathic CP from 54% to 14%. Pathogenic CFTR variants were the most common variant in patients with RAP (51%) and CP (43%). Among the 68 patients with pancreas divisum, other risk factor(s) were identified in 72%.

CONCLUSION

Genetic testing and a detailed assessment of smoking dose and duration reduce the proportion of patients with alcoholic and idiopathic pancreatitis. Other risk factor(s) for pancreatitis are found in the majority of patients with pancreas divisum further questioning its role as an independent risk factor.1. What is the current knowledge?Approximately 30% of patients with pancreatitis have no clear risk factor(s) and are categorized as having an idiopathic etiology.Pathogenic variant(s) as well as smoking dose and duration are well-established risk factors for recurrent acute and chronic pancreatitis but are not widely recognized or incorporated into clinical practice.2. What is new here?Genetic testing and a detailed assessment of smoking dose and duration reduced the proportion of patients with alcoholic and idiopathic acute recurrent and chronic pancreatitis.Approximately three-fourths of patients with pancreas divisum have a risk factor for pancreatitis.

Evidence-based clinical practice guidelines for chronic pancreatitis 2021

BACKGROUND

Chronic pancreatitis (CP) is defined according to the recently proposed mechanistic definition as a pathological fibro-inflammatory syndrome of the pancreas in individuals with genetic, environmental, and/or other risk factors who develop persistent pathological responses to parenchymal injury or stress.

METHODS

The clinical practice guidelines for CP in Japan were revised in 2021 based on the 2019 Japanese clinical diagnostic criteria for CP, which incorporate the concept of a pathogenic fibro-inflammatory syndrome in the pancreas. In this third edition, clinical questions are reclassified into clinical questions, background questions, and future research questions.

RESULTS

Based on analysis of newly accumulated evidence, the strength of evidence and recommendations for each clinical question is described in terms of treatment selection, lifestyle guidance, pain control, treatment of exocrine and endocrine insufficiency, and treatment of complications. A flowchart outlining indications, treatment selection, and policies for cases in which treatment is ineffective is provided. For pain control, pharmacological treatment and the indications and timing for endoscopic and surgical treatment have been updated in the revised edition.

CONCLUSIONS

These updated guidelines provide clinicians with useful information to assist in the diagnosis and treatment of CP.

Bicarbonate Transport in Cystic Fibrosis and Pancreatitis

CFTR, the cystic fibrosis (CF) gene-encoded epithelial anion channel, has a prominent role in driving chloride, bicarbonate and fluid secretion in the ductal cells of the exocrine pancreas. Whereas severe mutations in CFTR cause fibrosis of the pancreas in utero, CFTR mutants with residual function, or CFTR variants with a normal chloride but defective bicarbonate permeability (CFTR^BD), are associated with an enhanced risk of pancreatitis. Recent studies indicate that CFTR function is not only compromised in genetic but also in selected patients with an acquired form of pancreatitis induced by alcohol, bile salts or smoking. In this review, we summarize recent insights into the mechanism and regulation of CFTR-mediated and modulated bicarbonate secretion in the pancreatic duct, including the role of the osmotic stress/chloride sensor WNK1 and the scaffolding protein IRBIT, and current knowledge about the role of CFTR in genetic and acquired forms of pancreatitis. Furthermore, we discuss the perspectives for CFTR modulator therapy in the treatment of exocrine pancreatic insufficiency and pancreatitis and introduce pancreatic organoids as a promising model system to study CFTR function in the human pancreas, its role in the pathology of pancreatitis and its sensitivity to CFTR modulators on a personalized basis.

Genetic Variation in ABCC4 and CFTR and Acute Pancreatitis during Treatment of Pediatric Acute Lymphoblastic Leukemia

Background: Acute pancreatitis (AP) is a serious, mechanistically not entirely resolved side effect of L-asparaginase-containing treatment for acute lymphoblastic leukemia (ALL). To find new candidate variations for AP, we conducted a genome-wide association study (GWAS). Methods: In all, 1,004,623 single-nucleotide variants (SNVs) were analyzed in 51 pediatric ALL patients with AP (cases) and 1388 patients without AP (controls). Replication used independent patients. Results: The top-ranked SNV (rs4148513) was located within the ABCC4 gene (odds ratio (OR) 84.1; p = 1.04 × 10⁻¹⁴). Independent replication of our 20 top SNVs was not supportive of initial results, partly because rare variants were neither present in cases nor present in controls. However, results of combined analysis (GWAS and replication cohorts) remained significant (e.g., rs4148513; OR = 47.2; p = 7.31 × 10⁻⁹). Subsequently, we sequenced the entire ABCC4 gene and its close relative, the cystic fibrosis associated CFTR gene, a strong AP candidate gene, in 48 cases and 47 controls. Six AP-associated variants in ABCC4 and one variant in CFTR were detected. Replication confirmed the six ABCC4 variants but not the CFTR variant. Conclusions: Genetic variation within the ABCC4 gene was associated with AP during the treatment of ALL. No association of AP with CFTR was observed. Larger international studies are necessary to more conclusively assess the risk of rare clinical phenotypes.

Chemical pancreatectomy: an unconventional approach to preventing autodigestion in pancreatitis

Due to progressive inflammation, chronic pancreatitis destroys both the exocrine and endocrine pancreas and sensitizes pancreatic nerves, leading to unremitting pain. Unfortunately, there are no treatments for pancreatic inflammation and approaches to ameliorate pain are suboptimal. Pancreatic inflammation is particularly problematic because damage to acinar cells causes local release of digestive enzymes, which initiate pancreatic autodigestion. The combination of autodigestion and inflammation is unique to pancreatitis and undoubtedly contributes to the difficulty in devising effective treatments. In this issue of the JCI, Saleh et al. describe a nonsurgical technique to ablate pancreatic acinar cells, thus eliminating the source of digestive enzymes and preventing autodigestion. In mice and a nonhuman primate model, this approach effectively reduced inflammation and pain while preserving islet cell function. These findings support the concept that ongoing acinar cell damage is at the root of chronic pancreatitis and provide a possible strategy for clinical treatment.

[Cystic fibrosis: From gene discovery to precision medicine]

The discovery in 1989 that cystic fibrosis, the most common life-shortening hereditary disease in Caucasians, was caused by mutations in cystic fibrosis transmembrane conductance regulator (CFTR) gene, put in motion whole new areas of research, diagnosis, and therapeutic development. In this review, we focus on the most important advances in our understanding of the molecular basis of CFTR dysfunction. To date, over 2,000 CFTR mutations belonging to six protein-defect classes have been identified, increasing vastly our understanding of genotype/phenotype correlations. In the last 30 years, major achievements have been made in neonatal screening, antenatal diagnosis, and crucially with recent breakthroughs in the development of CFTR-directed therapies that may be effective for 90% of patients, paving the way for precision medicine.

Severe COVID-19 in Hospitalized Carriers of Single CFTR Pathogenic Variants

The clinical presentation of COVID-19 is extremely heterogeneous, ranging from asymptomatic to severely ill patients. Thus, host genetic factors may be involved in determining disease presentation and progression. Given that carriers of single cystic fibrosis (CF)-causing variants of the CFTR gene—CF-carriers—are more susceptible to respiratory tract infections, our aim was to determine their likelihood of undergoing severe COVID-19. We implemented a cohort study of 874 individuals diagnosed with COVID-19, during the first pandemic wave in Italy. Whole exome sequencing was performed and validated CF-causing variants were identified. Forty subjects (16 females and 24 males) were found to be CF-carriers. Among mechanically ventilated patients, CF-carriers were more represented (8.7%) and they were significantly (p < 0.05) younger (mean age 51 years) compared to noncarriers (mean age 61.42 years). Furthermore, in the whole cohort, the age of male CF-carriers was lower, compared to noncarriers (p < 0.05). CF-carriers had a relative risk of presenting an abnormal inflammatory response (CRP ≥ 20 mg/dL) of 1.69 (p < 0.05) and their hazard ratio of death at day 14 was 3.10 (p < 0.05) in a multivariate regression model, adjusted for age, sex and comorbidities. In conclusion, CF-carriers are more susceptible to the severe form of COVID-19, showing also higher risk of 14-day death.

Current Diagnosis and Management of Primary Chylomicronemia

Primary chylomicronemia (PCM) is a rare and intractable disease characterized by marked accumulation of chylomicrons in plasma. The levels of plasma triglycerides (TGs) typically range from 1,000 - 15,000 mg/dL or higher.

PCM is caused by defects in the lipoprotein lipase (LPL) pathway due to genetic mutations, autoantibodies, or unidentified causes. The monogenic type is typically inherited as an autosomal recessive trait with loss-of-function mutations in LPL pathway genes ( LPL , LMF1 , GPIHBP1 , APOC2 , and APOA5 ). Secondary/environmental factors (diabetes, alcohol intake, pregnancy, etc.) often exacerbate hypertriglyceridemia (HTG).

The signs, symptoms, and complications of chylomicronemia include eruptive xanthomas, lipemia retinalis, hepatosplenomegaly, and acute pancreatitis with onset as early as in infancy. Acute pancreatitis can be fatal and recurrent episodes of abdominal pain may lead to dietary fat intolerance and failure to thrive.

The main goal of treatment is to prevent acute pancreatitis by reducing plasma TG levels to at least less than 500-1,000 mg/dL. However, current TG-lowering medications are generally ineffective for PCM. The only other treatment options are modulation of secondary/environmental factors. Most patients need strict dietary fat restriction, which is often difficult to maintain and likely affects their quality of life.

Timely diagnosis is critical for the best prognosis with currently available management, but PCM is often misdiagnosed and undertreated. The aim of this review is firstly to summarize the pathogenesis, signs, symptoms, diagnosis, and management of PCM, and secondly to propose simple diagnostic criteria that can be readily translated into general clinical practice to improve the diagnostic rate of PCM. In fact, these criteria are currently used to define eligibility to receive social support from the Japanese government for PCM as a rare and intractable disease.

Nevertheless, further research to unravel the molecular pathogenesis and develop effective therapeutic modalities is warranted. Nationwide registry research on PCM is currently ongoing in Japan with the aim of better understanding the disease burden as well as the unmet needs of this life-threatening disease with poor therapeutic options.

Pancreatitis severity in mice with impaired CFTR function but pancreatic sufficiency is mediated via ductal and inflammatory cells-Not acinar cells

Mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR) are an established risk factor for cystic fibrosis (CF) and chronic pancreatitis. Whereas patients with CF usually develop complete exocrine pancreatic insufficiency, pancreatitis patients with CFTR mutations have mostly preserved exocrine pancreatic function. We therefore used a strain of transgenic mice with significant residual CFTR function (CFTR^tm1HGU ) to induce pancreatitis experimentally by serial caerulein injections. Protease activation and necrosis were investigated in isolated acini, disease severity over 24h, pancreatic function by MRI, isolated duct stimulation and faecal chymotrypsin, and leucocyte function by ex vivo lipopolysaccharide (LPS) stimulation. Pancreatic and lung injury were more severe in CFTR^tm1HGU but intrapancreatic trypsin and serum enzyme activities higher than in wild-type controls only at 8h, a time interval previously attributed to leucocyte infiltration. CCK-induced trypsin activation and necrosis in acini from CFTR^tm1HGU did not differ from controls. Fluid and bicarbonate secretion were greatly impaired, whereas faecal chymotrypsin remained unchanged. LPS stimulation of splenocytes from CFTR^tm1HGU resulted in increased INF-γ and IL-6, but decreased IL-10 secretion. CFTR mutations that preserve residual pancreatic function significantly increase the severity of experimental pancreatitis-mostly via impairing duct cell function and a shift towards a pro-inflammatory phenotype, not by rendering acinar cells more susceptible to pathological stimuli.

The reversion variant (p.Arg90Leu) at the evolutionarily adaptive p.Arg90 site in CELA3B predisposes to chronic pancreatitis

A gain-of-function missense variant in the CELA3B gene, p.Arg90Cys (c.268C>T), has recently been reported to cause pancreatitis in an extended pedigree. Herein, we sequenced the CELA3B gene in 644 genetically unexplained French chronic pancreatitis (CP) patients (all unrelated) and 566 controls. No obvious loss-of-function variants were identified. None of the six low-frequency or common missense variants detected showed significant association with CP. Nor did the aggregate rare/very rare missense variants (n = 14) show any significant association with CP. However, p.Arg90Leu (c.269G>T), which was found in four patients but no controls, and affects the same amino acid as p.Arg90Cys, serves to revert p.Arg90 to the human elastase ancestral allele. As p.Arg90Leu has previously been shown to exert a similar functional effect to that of p.Arg90Cys, our findings not only confirm the involvement of CELA3B in the etiology of CP but also pinpoint a new evolutionarily adaptive site in the human genome.

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.

Differences in Age at Onset of Symptoms, and Effects of Genetic Variants, in Patients With Early vs Late-Onset Idiopathic Chronic Pancreatitis in a North American Cohort

BACKGROUND & AIMS

Idiopathic chronic pancreatitis (ICP) is the second most common subtype of CP. In 1994, researchers reported the bimodal age at onset of ICP symptoms: early onset ICP (EO-ICP; median age, 19.2 y) and late-onset ICP (LO-ICP; median age, 56.2 y). Ages of onset and clinical features of ICP differed from those of alcohol-related CP (ACP). However, variants in PRSS1 had not yet been associated with ICP. We reexamined ages of onset of ICP in a large, North American cohort of patients, and investigated the effects of genetic factors and alcohol use in patients with EO-ICP, LO-ICP, and ACP.

METHODS

We performed a cross-sectional analysis of patients with CP of European ancestry enrolled in the North American Pancreatitis Study 2, a prospective study of 1195 patients with CP from 26 centers in the United States from August 2000 through December 2014. We compared age at onset of symptoms for 130 patients with CP who were lifetime abstainers from alcohol (61 patients with early onset and 69 patients with late onset), 308 light to moderate alcohol drinkers with CP, and 225 patients with ACP and heavy to very heavy alcohol use. DNA from available patients was analyzed for variants associated with CP in SPINK1, CFTR, and CTRC. The Kruskal-Wallis test was used to compare continuous variables across groups and based on genetic variants.

RESULTS

Median ages at onset of symptoms were 20 years for patients with EO-ICP and no alcohol use, 58 years for patients with LO-ICP and no alcohol use, 47 years for light to moderate alcohol drinkers with CP, and 44 years for patients with ACP. A higher proportion of patients with EO-ICP had constant pain (65%) than patients with LO-ICP (31%) (P = .04). A higher proportion of patients with ACP had pseudocysts (43%) than patients with EO-ICP (11%) (P = .001). A higher proportion of patients with EO-ICP had pathogenic variants in SPINK1, CFTR, or CTRC (49%) than patients with LO-ICP (23%), light to moderate alcohol drinking with CP (26%), or ACP (23%) (P = .001). Among patients with variants in SPINK1, those with EO-ICP had onset of symptoms at a median age of 12 years, and light to moderate alcohol drinkers with CP had an age at onset of 24 years. Among patients with variants in CFTR, light to moderate alcohol drinkers had an age at onset of symptoms of 41 years, but this variant did not affect age at onset of EO-ICP or ACP.

CONCLUSIONS

We confirmed previously reported ages at onset of symptoms for EO-ICP and LO-ICP in a North American cohort. We found differences in clinical features among patients with EO-ICP, LO-ICP, and ACP. Almost half of patients with EO-ICP have genetic variants associated with CP, compared with approximately one quarter of patients with LO-CP or ACP. Genetic variants affect ages at onset of symptoms in some groups.

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

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

Cyclic Peptidyl Inhibitors against CAL/CFTR Interaction for Treatment of Cystic Fibrosis

Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, encoding for a chloride ion channel. Membrane expression of CFTR is negatively regulated by CFTR-associated ligand (CAL). We previously showed that inhibition of the CFTR/CAL interaction with a cell-permeable peptide improves the function of rescued F508del-CFTR. In this study, optimization of the peptidyl inhibitor yielded PGD97, which exhibits a K_D value of 6 nM for the CAL PDZ domain, ≥ 130-fold selectivity over closely related PDZ domains, and a serum t_1/2 of >24 h. In patient-derived F508del homozygous cells, PGD97 (100 nM) increased short-circuit currents by ∼3-fold and further potentiated the therapeutic effects of small-molecule correctors (e.g., VX-661) by ∼2-fold (with an EC₅₀ of ∼10 nM). Our results suggest that PGD97 may be used as a novel treatment for CF, either as a single agent or in combination with small-molecule correctors/potentiators.

Genetic diagnosis in practice: From cystic fibrosis to CFTR-related disorders

Cystic fibrosis (CF) is a channelopathy caused by mutations in the gene encoding the CF transmembrane conductance regulator (CFTR) protein. Diagnosis of CF has long relied on a combination of clinical (including gastrointestinal and/or respiratory) symptoms and elevated sweat chloride concentration. After cloning of the CFTR gene in 1989, genetic analysis progressively became an important aspect of diagnosis. Although combination of sweat test and genetic analysis have simplified the diagnosis of CF in most cases, difficult situations remain, especially in cases that do not fulfill all diagnostic criteria. Such situations are most frequently encountered in patients presenting with a single-organ disease (e.g., congenital absence of the vas deferens, pancreatitis, bronchiectasis) leading to a diagnosis of CFTR-related disorder, or when the presence/ absence of CF is not resolved after newborn screening. This article reviews the diagnostic criteria of CF, with special emphasis on genetic testing. © 2020 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.

Analysis of GPRC6A variants in different pancreatitis etiologies

BACKGROUND

The G-protein-coupled receptor Class C Group 6 Member A (GPRC6A) is activated by multiple ligands and is important for the regulation of calcium homeostasis. Extracellular calcium is capable to increase NLRP3 inflammasome activity of the innate immune system and deletion of this proinflammatory pathway mitigated pancreatitis severity in vivo. As such this pathway and the GPRC6A receptor is a reasonable candidate gene for pancreatitis. Here we investigated the prevalence of sequence variants in the GPRC6A locus in different pancreatitis aetiologies.

METHODS

We selected 6 tagging SNPs with the SNPinfo LD TAG SNP Selection tool and the functional relevant SNP rs6907580 for genotyping. Cohorts from Germany, further European countries and China with up to 1,124 patients and 1,999 controls were screened for single SNPs with melting curve analysis.

RESULTS

We identified an association of rs1606365(G) with alcoholic chronic pancreatitis in a German (odds ratio (OR) 0.76, 95% confidence interval (CI) 0.65-0.89, p = 8 × 10^-5) and a Chinese cohort (OR 0.78, 95% CI 0.64-0.96, p = 0.02). However, this association was not replicated in a combined cohort of European patients (OR 1.18, 95% CI 0.99-1.41, p = 0.07). Finally, no association was found with acute and non-alcoholic chronic pancreatitis.

CONCLUSIONS

Our results support a potential role of calcium sensing receptors and inflammasome activation in alcoholic chronic pancreatitis development. As the functional consequence of the associated variant is unclear, further investigations might elucidate the relevant mechanisms.

Complex Genetics in Pancreatitis: Insights Gained From a New Candidate Locus Panel

OBJECTIVES

Chronic pancreatitis is the end stage of a pathologic inflammatory syndrome with multiple etiological factors, including genetic. We hypothesized that some pancreatitis etiology originates in pancreatic acinar or duct cells and requires both injury and compensatory mechanism failure.

METHODS

One hundred pancreatitis patients were assessed using a DNA sequencing panel for pancreatitis. Cooccurrence of variants within and between genes was measured. Gene coexpression was confirmed via published single-cell RNA sequencing.

RESULTS

One hundred and twenty-one variants were identified in 2 or more patients, 15 of which were enriched compared with reference populations. Single cell RNA-sequencing data verified coexpression of GGT1, CFTR, and PRSS1 in duct cells, PRSS1, CPA1, CEL, CTRC, and SPINK1 in acinar cells, and UBR1 in both. Multiple-risk variants with injury/stress effects (CEL, CFTR, CPA1, PRSS1) and impaired cell protection (CTRC, GGT1, SPINK1, UBR1) cooccur within duct cells, acinar cells, or both.

CONCLUSIONS

Pancreatitis is a complex disorder with genetic interactions across genes and cell types. These findings suggest a new, non-Mendelian genetic risk/etiology paradigm where a combination of nonpathogenic genetic risk variants in groups of susceptibility genes and injury/dysfunction response genes contribute to acquired pancreatic disease.

BAP1 is a haploinsufficient tumor suppressor linking chronic pancreatitis to pancreatic cancer in mice

Chronic pancreatitis represents a risk factor for the development of pancreatic cancer. We find that heterozygous loss of histone H2A lysine 119 deubiquitinase BAP1 (BRCA1 Associated Protein-1) associates with a history of chronic pancreatitis and occurs in 25% of pancreatic ductal adenocarcinomas and 40% of acinar cell carcinomas. Deletion or heterozygous loss of Bap1 in murine pancreata causes genomic instability, tissue damage, and pancreatitis with full penetrance. Concomitant expression of Kras^G12D leads to predominantly intraductal papillary mucinous neoplasms and mucinous cystic neoplasms, while pancreatic intraepithelial neoplasias are rarely detected. These lesions progress to metastatic pancreatic cancer with high frequency. Lesions with histological features mimicking Acinar Cell Carcinomas are also observed in some tumors. Heterozygous mice also develop pancreatic cancer suggesting a haploinsufficient tumor suppressor role for BAP1. Mechanistically, BAP1 regulates genomic stability, in a catalytic independent manner, and its loss confers sensitivity to irradiation and platinum-based chemotherapy in pancreatic cancer.

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

BACKGROUND & AIMS

Changes in pancreatic calcium levels affect secretion and might be involved in development of chronic pancreatitis (CP). We investigated the association of CP with the transient receptor potential cation channel subfamily V member 6 gene (TRPV6), which encodes a Ca²⁺-selective ion channel, in an international cohort of patients and in mice.

METHODS

We performed whole-exome DNA sequencing from a patient with idiopathic CP and from his parents, who did not have CP. We validated our findings by sequencing DNA from 300 patients with CP (not associated with alcohol consumption) and 1070 persons from the general population in Japan (control individuals). In replication studies, we sequenced DNA from patients with early-onset CP (20 years or younger) not associated with alcohol consumption from France (n = 470) and Germany (n = 410). We expressed TRPV6 variants in HEK293 cells and measured their activity using Ca²⁺ imaging assays. CP was induced by repeated injections of cerulein in TRPV6^mut/mut mice.

RESULTS

We identified the variants c.629C>T (p.A210V) and c.970G>A (p.D324N) in TRPV6 in the index patient. Variants that affected function of the TRPV6 product were found in 13 of 300 patients (4.3%) and 1 of 1070 control individuals (0.1%) from Japan (odds ratio [OR], 48.4; 95% confidence interval [CI], 6.3-371.7; P = 2.4 × 10^-8). Twelve of 124 patients (9.7%) with early-onset CP had such variants. In the replication set from Europe, 18 patients with CP (2.0%) carried variants that affected the function of the TRPV6 product compared with 0 control individuals (P = 6.2 × 10^-8). Variants that did not affect the function of the TRPV6 product (p.I223T and p.D324N) were overrepresented in Japanese patients vs control individuals (OR, 10.9; 95% CI, 4.5-25.9; P = 7.4 × 10^-9 for p.I223T and P = .01 for p.D324N), whereas the p.L299Q was overrepresented in European patients vs control individuals (OR, 3.0; 95% CI, 1.9-4.8; P = 1.2 × 10^-5). TRPV6^mut/mut mice given cerulein developed more severe pancreatitis than control mice, as shown by increased levels of pancreatic enzymes, histologic alterations, and pancreatic fibrosis.

CONCLUSIONS

We found that patients with early-onset CP not associated with alcohol consumption carry variants in TRPV6 that affect the function of its product, perhaps by altering Ca²⁺ balance in pancreatic cells. TRPV6 regulates Ca²⁺ homeostasis and pancreatic inflammation.

Diagnosis and Management of Chronic Pancreatitis: A Review

IMPORTANCE

Chronic pancreatitis (CP) is a chronic inflammatory and fibrotic disease of the pancreas with a prevalence of 42 to 73 per 100 000 adults in the United States.

OBSERVATIONS

Both genetic and environmental factors are thought to contribute to the pathogenesis of CP. Environmental factors associated with CP include alcohol abuse (odds ratio [OR], 3.1; 95% CI, 1.87-5.14) for 5 or more drinks per day vs abstainers and light drinkers as well as smoking (OR, 4.59; 95% CI, 2.91-7.25) for more than 35 pack-years in a case-control study involving 971 participants. Between 28% to 80% of patients are classified as having "idiopathic CP." Up to 50% of these individuals have mutations of the trypsin inhibitor gene (SPINK1) or the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Approximately 1% of people diagnosed with CP may have hereditary pancreatitis, associated with cationic trypsinogen (PRSS1) gene mutations. Approximately 80% of people with CP present with recurrent or chronic upper abdominal pain. Long-term sequelae include diabetes in 38% to 40% and exocrine insufficiency in 30% to 48%. The diagnosis is based on pancreatic calcifications, ductal dilatation, and atrophy visualized by imaging with computed tomography, magnetic resonance imaging, or both. Endoscopic ultrasound can assist in making the diagnosis in patients with a high index of suspicion such as recurrent episodes of acute pancreatitis when imaging is normal or equivocal. The first line of therapy consists of advice to discontinue use of alcohol and smoking and taking analgesic agents (nonsteroidal anti-inflammatory drugs and weak opioids such as tramadol). A trial of pancreatic enzymes and antioxidants (a combination of multivitamins, selenium, and methionine) can control symptoms in up to 50% of patients. Patients with pancreatic ductal obstruction due to stones, stricture, or both may benefit from ductal drainage via endoscopic retrograde cholangiopancreatography (ERCP) or surgical drainage procedures, such as pancreaticojejunostomy with or without pancreatic head resection, which may provide better pain relief among people who do not respond to endoscopic therapy.

CONCLUSIONS AND RELEVANCE

Chronic pancreatitis often results in chronic abdominal pain and is most commonly caused by excessive alcohol use, smoking, or genetic mutations. Treatment consists primarily of alcohol and smoking cessation, pain control, replacement of pancreatic insufficiency, or mechanical drainage of obstructed pancreatic ducts for some patients.

Identification and management of pancreas divisum

Introduction: Pancreas divisum is the most common congenital malformation of the pancreas with the majority asymptomatic. The etiological role, pathogenesis, clinical significance and management of pancreas divisum in pancreatic disease has not been clearly defined and our understanding is yet to be fully elucidated.Areas covered: This review describes the role of pancreas divisum in the development of pancreatic disease and the ambiguity related to it. In our attempt to offer clarity, a comprehensive search on PubMed, Ovid, Embase and Cochrane Library from inception to May 2019 was undertaken using key words "pancreas divisum", "idiopathic recurrent acute pancreatitis" and "chronic pancreatitis".Expert opinion: Current research fails to define a clear association between pancreas divisum and pancreatic disease. Though debatable, several studies do suggest a pathological role of pancreas divisum in pancreatic disease and a benefit of minor papilla therapy in the setting of acute recurrent pancreatitis. Surgical and endoscopic therapeutic modalities have not been directly compared. With the current data available, it would be imprudent to advise a definitive line of management for pancreatic disease associated with pancreas divisum and should involve a comprehensive discussion with the individual patient to define expectations before embarking on any medical and/or interventional therapy.

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

OBJECTIVES

Premature activation of the digestive protease trypsin within the pancreatic parenchyma is a critical factor in the pathogenesis of pancreatitis. Alterations in genes that affect intrapancreatic trypsin activity are associated with chronic pancreatitis (CP). Recently, carboxyl ester lipase emerged as a trypsin-independent risk gene. Here, we evaluated pancreatic lipase (PNLIP) as a potential novel susceptibility gene for CP.

METHODS

We analyzed all 13 PNLIP exons in 429 nonalcoholic patients with CP and 600 control subjects from Germany, in 632 patients and 957 controls from France, and in 223 patients and 1,070 controls from Japan by DNA sequencing. Additionally, we analyzed selected exons in further 545 patients with CP and 1,849 controls originating from Germany, United States, and India. We assessed the cellular secretion, lipase activity, and proteolytic stability of recombinant PNLIP variants.

RESULTS

In the German discovery cohort, 8/429 (1.9%) patients and 2/600 (0.3%) controls carried a PNLIP missense variant (P = 0.02, odds ratio [OR] = 5.7, 95% confidence interval [CI] = 1.1-38.9). Variants detected in patients were prone to proteolytic degradation by trypsin and chymotrypsin. In the French replication cohort, protease-sensitive variants were also enriched in patients with early-onset CP (5/632 [0.8%]) vs controls (1/957 [0.1%]) (P = 0.04, OR = 7.6, 95% CI = 0.9-172.9). In contrast, we detected no protease-sensitive variants in the non-European populations. In the combined European data, protease-sensitive variants were found in 13/1,163 cases (1.1%) and in 3/3,000 controls (0.1%) (OR = 11.3, 95% CI = 3.0-49.9, P < 0.0001).

CONCLUSIONS

Our data indicate that protease-sensitive PNLIP variants are novel genetic risk factors for the development of CP.

Genetics, Cell Biology, and Pathophysiology of Pancreatitis

Since the discovery of the first trypsinogen mutation in families with hereditary pancreatitis, pancreatic genetics has made rapid progress. The identification of mutations in genes involved in the digestive protease-antiprotease pathway has lent additional support to the notion that pancreatitis is a disease of autodigestion. Clinical and experimental observations have provided compelling evidence that premature intrapancreatic activation of digestive proteases is critical in pancreatitis onset. However, disease course and severity are mostly governed by inflammatory cells that drive local and systemic immune responses. In this article, we review the genetics, cell biology, and immunology of pancreatitis with a focus on protease activation pathways and other early events.

The CFTR gene variants in Japanese children with idiopathic pancreatitis

The cystic fibrosis transmembrane conductance regulator (CFTR) gene has been reported as one of the pancreatitis susceptibility genes. Although many variants of CFTR have been reported in Caucasian patients, there are few data in Japanese patients. We aimed to survey CFTR variants in Japanese children with idiopathic pancreatitis. Twenty-eight Japanese paediatric patients with idiopathic pancreatitis were enroled, who were not previously diagnosed by genetic analysis of PRSS1 and SPINK1. The entire CFTR gene was sequenced in the patients by combining LA-PCR and next-generation sequencing analysis. To determine a splice-affecting variant, CFTR expression was investigated in the nasal epithelial cells by RT-PCR. One (3.6%) and 15 (53.6%) of 28 patients had pathogenic and functionally affected variants in the CFTR gene, respectively. Two variants, p.Arg352Gln and p.Arg1453Trp, were found more frequently in the patients compared with one in Japanese healthy controls (p = 0.0078 and 0.044, respectively). We confirmed skipping of exon 10 in the nasal epithelial cells in one patient having a splice-affecting variant (c.1210-12 T(5)) in intron 9. Functionally affected variants of the CFTR gene are not so rare in Japanese paediatric patients with idiopathic pancreatitis. Surveying CFTR gene variants in a Japanese sample could help identify pancreatitis risk in these children.

Mutations in a cystic fibrosis-related gene could help identify Japanese children at risk of developing pancreatic inflammation. Tadashi Kaname, of Tokyo’s National Center for Child Health and Development, and colleagues sequenced the cystic fibrosis transmembrane conductance regulator gene (CFTR) in 28 Japanese children with pancreatitis of unknown origin. The gene is involved in the development of cystic fibrosis and has been reported to be associated with pancreatitis but little is known about its role in idiopathic pancreatitis in Asian populations. The team found CFTR gene mutations in 16 out of the 28 children. Cystic fibrosis is uncommon among Japanese, so CFTR mutations were also thought to be rare. The study suggests, however, that mutations might not be so rare in Japanese children with idiopathic pancreatitis and could help identify those at risk of developing the condition.

Toward a clinical diagnostic pipeline for SPINK1 intronic variants

Background

The clinical significance of SPINK1 intronic variants in chronic pancreatitis has been previously assessed by various approaches including a cell culture-based full-length gene assay. A close correlation between the results of this assay and in silico splicing prediction was apparent. However, until now, a clinical diagnostic pipeline specifically designed to classify SPINK1 intronic variants accurately and efficiently has been lacking. Herein, we present just such a pipeline and explore its efficacy and potential utility in potentiating the classification of newly described SPINK1 intronic variants.

Results

We confirm a close correlation between in silico splicing prediction and results from the cell culture-based full-length gene assay in the context of three recently reported pathogenic SPINK1 intronic variants. We then integrated in silico splicing prediction and the full-length gene assay into a stepwise approach and tested its utility in the classification of two novel datasets of SPINK1 intronic variants. The first dataset comprised 16 deep intronic variants identified in 52 genetically unexplained Chinese chronic pancreatitis patients by sequencing the entire intronic sequence of the SPINK1 gene. The second dataset comprised five novel rare proximal intronic variants identified through the routine analysis of the SPINK1 gene in French pancreatitis patients. Employing a minor allele frequency of > 5% as a population frequency filter, 6 of the 16 deep intronic variants were immediately classified as benign. In silico prediction of the remaining ten deep intronic variants and the five rare proximal intronic variants with respect to their likely impact on splice site selection suggested that only one proximal intronic variant, c.194 + 5G > A, was likely to be of functional significance. Employing the cell culture-based full-length gene assay, we functionally analyzed c.194 + 5G > A, together with seven predicted non-functional variants, thereby validating their predicted effects on splicing in all cases.

Conclusions

We demonstrated the accuracy and efficiency of in silico prediction in combination with the cell culture-based full-length gene assay for the classification of SPINK1 intronic variants. Based upon these findings, we propose an operational pipeline for classifying SPINK1 intronic variants in the clinical diagnostic setting.

Electronic supplementary material

The online version of this article (10.1186/s40246-019-0193-7) contains supplementary material, which is available to authorized users.

CFTR inhibits the invasion and growth of esophageal cancer cells by inhibiting the expression of NF-κB

Our study aimed to explore the function of cystic fibrosis transmembrane conductance regulator (CFTR) in esophageal cancer. Twenty patients with esophageal squamous cell carcinoma (ESCC) and 20 patients with esophageal adenocarcinoma (EA) were enrolled in this study. The levels of CFTR and NF-κB in tumor tissues and adjacent normal tissues were detected, respectively. The expression of CFTR were detected by qRT-PCR and Western blot in normal esophageal cell line, esophagus squamous cell, carcinoma cell lines, and EA cell lines, respectively. Effects of CFTR silencing and overexpression on NF-κB protein expression were detected by Western blot. Transwell assay was performed to detect cell invasion. Mouse tumor model was established and the effect of CFTR inhibitor on tumor growth was examined. The expression of CFTR was downregulated in tumor tissues and cancer cell lines. CFTR silencing promoted the expression of NF-κB-p65 and NF-κB-p50, and the results of CFTR overexpression were reversed. In addition, CFTR silencing promoted the invasion of cancer cells and tumor growth in mice. Besides that, NF-κB inhibitor reduced the enhancing effects of CFTR silencing on esophageal cell invasion. We conclude that CFTR inhibits the growth and migration of esophageal cancer cells by downregulating of the NF-κB protein expression.

Pediatric Pancreatitis-Molecular Mechanisms and Management

Pediatric pancreatitis is an emerging field with an increasing incidence of disease. Management of pediatric pancreatitis is understudied and, therefore, extrapolated from adult studies (although the etiologies are different). There is evidence that feeding is safe in mild acute pancreatitis in children without increased pain or length of stay. Studies are needed to predict course of the disease, disease severity, and risk of chronic pancreatitis in children.

SPINK1, PRSS1, CTRC, and CFTR Genotypes Influence Disease Onset and Clinical Outcomes in Chronic Pancreatitis

Objectives

Rare pathogenic variants in the SPINK1, PRSS1, CTRC, and CFTR genes have been strongly associated with a risk of developing chronic pancreatitis (CP). However, their potential impact on the age of disease onset and clinical outcomes, as well as their potential interactions with environmental risk factors, remain unclear. These issues are addressed here in a large Chinese CP cohort.

Methods

We performed targeted next-generation sequencing of the four CP-associated genes in 1061 Han Chinese CP patients and 1196 controls. To evaluate gene–environment interactions, the patients were divided into three subgroups, idiopathic CP (ICP; n = 715), alcoholic CP (ACP; n = 206), and smoking-associated CP (SCP; n = 140). The potential impact of rare pathogenic variants on the age of onset of CP and clinical outcomes was evaluated using the Kaplan–Meier model.

Results

We identified rare pathogenic genotypes involving the SPINK1, PRSS1, CTRC, and/or CFTR genes in 535 (50.42%) CP patients but in only 71 (5.94%) controls (odds ratio = 16.12; P < 0.001). Mutation-positive patients had significantly earlier median ages at disease onset and at diagnosis of pancreatic stones, diabetes mellitus and steatorrhea than mutation-negative ICP patients. Pathogenic genotypes were present in 57.1, 39.8, and 32.1% of the ICP, ACP, and SCP patients, respectively, and influenced age at disease onset and clinical outcomes in all subgroups.

Conclusions

We provide evidence that rare pathogenic variants in the SPINK1, PRSS1, CTRC, and CFTR genes significantly influence the age of onset and clinical outcomes of CP. Extensive gene–environment interactions were also identified.

Acquired cystic fibrosis transmembrane conductance regulator dysfunction

Sinonasal respiratory epithelium is a highly regulated barrier that employs mucociliary clearance (MCC) as the airways first line of defense. The biological properties of the airway surface liquid (ASL), combined with coordinated ciliary beating, are critical components of the mucociliary apparatus. The ASL volume and viscosity is modulated, in part, by the cystic fibrosis transmembrane conductance regulator (CFTR). The CFTR is an anion transporter of chloride (Cl⁻) and bicarbonate (HCO₃⁻) that is located on the apical surface of respiratory epithelium and exocrine glandular epithelium. Improved understanding of how dysfunction or deficiency of CFTR influences the disease process in both genetically defined cystic fibrosis (CF) and acquired conditions has provided further insight into potential avenues of treatment. This review discusses the latest data regarding acquired CFTR deficiency and use of CFTR specific treatment strategies for CRS and other chronic airway diseases.

The Role of Genetics in Pancreatitis

Individuals with acute recurrent and chronic pancreatitis may have an inherited predisposition to the development of the disease. Pancreatitis in the setting of a significant family history of the disease can be classified as hereditary or familial pancreatitis. In this article, the authors closely examine the specific genes implicated in pancreatitis, investigate the role of genetic testing for diagnosis, and describe the impact of genetic testing results on clinical management.

Pancreatitis-Associated Genes and Pancreatic Cancer Risk: A Systematic Review and Meta-analysis

OBJECTIVE

The aim of this study was to evaluate the connection between pancreatic cancer (PC) and genetic variants associated with chronic pancreatitis via systematic review and meta-analysis.

METHODS

The data search was performed in 3 major databases (PubMed, Embase, and Cochrane Library). The selected studies have looked into the presence of the pancreatitis-associated genes in patients with PC and in control subjects, the outcome being the frequency of the mutations in the 2 groups. For the binary outcomes, pooled odds ratio (OR) and 95% confidence interval (CI) were calculated.

RESULTS

Ten articles proved to be eligible for the qualitative synthesis, and 8 articles were suitable for statistical analysis. Six case-control studies, comprising 929 PC cases and 1890 control subjects for serine protease inhibitor Kazal type 1 (SPINK1) mutations, and 5 case-control studies, comprising 1674 PC cases and 19,036 control subjects for CFTR mutations, were enrolled in our analysis. SPINK1 mutations showed no association with PC (OR, 1.52; 95% CI, 0.67-3.45; P = 0.315), whereas mutations in CFTR modestly increased the risk of PC (OR, 1.41; 95% CI, 1.07-1.84; P = 0.013).

CONCLUSION

Our meta-analysis showed that mutations in CFTR modestly increase the risk of PC, whereas no association was found between SPINK1 and PC.

Genetic predisposition in pancreatitis

PURPOSE OF REVIEW

Genetic mutations are the primary cause for acute recurrent (ARP) and chronic pancreatitis in children. Further, our medical approach for many diseases is changing from a one-drug therapy to more individualized therapeutic strategies. In respect to the therapeutic management of ARP/chronic pancreatitis, this entails an understanding of the individual, mainly genetic, risk factors that led to pancreatitis disease.

RECENT FINDINGS

New pancreatitis-associated genes are continuously emerging from increasingly large genetic cohort studies. Furthermore, newer research findings demonstrate that multiple genetic and nongenetic factors are required to increase the individual risk for developing ARP/chronic pancreatitis. Last, there is new exciting development towards targeted pancreatitis therapy in the future.

SUMMARY

This review introduces the current concept of ARP/chronic pancreatitis as a complex disease caused by multiple genetic and nongenetic factors. This warrants careful evaluation of these patients and ideally consultation of a pancreas expert to help understand individual genetic risk profiles and to provide more effective patient consultation.

Recurrent Acute Pancreatitis: Current Concepts in the Diagnosis and Management

PURPOSE OF REVIEW

There have been significant developments in the diagnosis, clinical approach, and management of patients with recurrent acute pancreatitis (RAP) in the last decade. This review systematically summarizes our current understanding of RAP.

NEW FINDINGS

Gallstones and alcohol are common causes of RAP. Non-alcohol non-biliary RAP (nAnB RAP) is a difficult group of patients after excluding these two causes because extensive workup is required to elucidate the etiology. Idiopathic RAP is diagnosed after excluding all the known causes and recurrence is noted to be higher in such patients. Patients with non-biliary RAP are prone to develop chronic pancreatitis (CP) suggesting a continuum from acute to recurrent to chronic pancreatitis. Often, patients destined to develop CP present at an earlier stage with RAP. Endoscopic ultrasound and magnetic resonance cholangiopancreatography (MRCP) are the investigations of choice to detect microlithiasis, choledocholithiasis, ductal abnormalities, peri-ampullary malignancies, and early changes of chronic pancreatitis. The role of pancreas divisum, sphincter of Oddi dysfunction, and anomalous pancreatobiliary union in causing RAP is controversial. Genetic testing may be advisable in younger patients.

CONCLUSION

With a focused approach and appropriate investigations, the etiology of RAP can be identified in a significant proportion of patients. Therapeutic options are limited and future research is needed to improve understanding of the disease.