Deciphering the complex interplay between pancreatic cancer, diabetes mellitus subtypes and obesity/BMI through causal inference and mediation analyses.

OBJECTIVES: To characterise the association between type 2 diabetes mellitus (T2DM) subtypes (new-onset T2DM (NODM) or long-standing T2DM (LSDM)) and pancreatic cancer (PC) risk, to explore the direction of causation through Mendelian randomisation (MR) analysis and to assess the mediation role of body mass index (BMI). DESIGN: Information about T2DM and related factors was collected from 2018 PC cases and 1540 controls from the PanGenEU (European Study into Digestive Illnesses and Genetics) study. A subset of PC cases and controls had glycated haemoglobin, C-peptide and genotype data. Multivariate logistic regression models were applied to derive ORs and 95% CIs. T2DM and PC-related single nucleotide polymorphism (SNP) were used as instrumental variables (IVs) in bidirectional MR analysis to test for two-way causal associations between PC, NODM and LSDM. Indirect and direct effects of the BMI-T2DM-PC association were further explored using mediation analysis. RESULTS: T2DM was associated with an increased PC risk when compared with non-T2DM (OR=2.50; 95% CI: 2.05 to 3.05), the risk being greater for NODM (OR=6.39; 95% CI: 4.18 to 9.78) and insulin users (OR=3.69; 95% CI: 2.80 to 4.86). The causal association between T2DM (57-SNP IV) and PC was not statistically significant (ORLSDM=1.08, 95% CI: 0.86 to 1.29, ORNODM=1.06, 95% CI: 0.95 to 1.17). In contrast, there was a causal association between PC (40-SNP IV) and NODM (OR=2.85; 95% CI: 2.04 to 3.98), although genetic pleiotropy was present (MR-Egger: p value=0.03). Potential mediating effects of BMI (125-SNPs as IV), particularly in terms of weight loss, were evidenced on the NODM-PC association (indirect effect for BMI in previous years=0.55). CONCLUSION: Findings of this study do not support a causal effect of LSDM on PC, but suggest that PC causes NODM. The interplay between obesity, PC and T2DM is complex.

Pancreatic cancer and autoimmune diseases: An association sustained by computational and epidemiological case-control approaches.

Deciphering the underlying genetic basis behind pancreatic cancer (PC) and its associated multimorbidities will enhance our knowledge toward PC control. The study investigated the common genetic background of PC and different morbidities through a computational approach and further evaluated the less explored association between PC and autoimmune diseases (AIDs) through an epidemiological analysis. Gene-disease associations (GDAs) of 26 morbidities of interest and PC were obtained using the DisGeNET public discovery platform. The association between AIDs and PC pointed by the computational analysis was confirmed through multivariable logistic regression models in the PanGen European case-control study population of 1,705 PC cases and 1,084 controls. Fifteen morbidities shared at least one gene with PC in the DisGeNET database. Based on common genes, several AIDs were genetically associated with PC pointing to a potential link between them. An epidemiologic analysis confirmed that having any of the nine AIDs studied was significantly associated with a reduced risk of PC (Odds Ratio (OR) = 0.74, 95% confidence interval (CI) 0.58-0.93) which decreased in subjects having ≥2 AIDs (OR = 0.39, 95%CI 0.21-0.73). In independent analyses, polymyalgia rheumatica, and rheumatoid arthritis were significantly associated with low PC risk (OR = 0.40, 95%CI 0.19-0.89, and OR = 0.73, 95%CI 0.53-1.00, respectively). Several inflammatory-related morbidities shared a common genetic component with PC based on public databases. These molecular links could shed light into the molecular mechanisms underlying PC development and simultaneously generate novel hypotheses. In our study, we report sound findings pointing to an association between AIDs and a reduced risk of PC.

Genome-wide association study identifies inversion in the CTRB1-CTRB2 locus to modify risk for alcoholic and non-alcoholic chronic pancreatitis.

OBJECTIVE: Alcohol-related pancreatitis is associated with a disproportionately large number of hospitalisations among GI disorders. Despite its clinical importance, genetic susceptibility to alcoholic chronic pancreatitis (CP) is poorly characterised. To identify risk genes for alcoholic CP and to evaluate their relevance in non-alcoholic CP, we performed a genome-wide association study and functional characterisation of a new pancreatitis locus. DESIGN: 1959 European alcoholic CP patients and population-based controls from the KORA, LIFE and INCIPE studies (n=4708) as well as chronic alcoholics from the GESGA consortium (n=1332) were screened with Illumina technology. For replication, three European cohorts comprising 1650 patients with non-alcoholic CP and 6695 controls originating from the same countries were used. RESULTS: We replicated previously reported risk loci CLDN2-MORC4, CTRC, PRSS1-PRSS2 and SPINK1 in alcoholic CP patients. We identified CTRB1-CTRB2 (chymotrypsin B1 and B2) as a new risk locus with lead single-nucleotide polymorphism (SNP) rs8055167 (OR 1.35, 95% CI 1.23 to 1.6). We found that a 16.6 kb inversion in the CTRB1-CTRB2 locus was in linkage disequilibrium with the CP-associated SNPs and was best tagged by rs8048956. The association was replicated in three independent European non-alcoholic CP cohorts of 1650 patients and 6695 controls (OR 1.62, 95% CI 1.42 to 1.86). The inversion changes the expression ratio of the CTRB1 and CTRB2 isoforms and thereby affects protective trypsinogen degradation and ultimately pancreatitis risk. CONCLUSION: An inversion in the CTRB1-CTRB2 locus modifies risk for alcoholic and non-alcoholic CP indicating that common pathomechanisms are involved in these inflammatory disorders.

Reduced risk of pancreatic cancer associated with asthma and nasal allergies.

OBJECTIVE: Studies indicate an inverse association between ductal adenocarcinoma of the pancreas (PDAC) and nasal allergies. However, controversial findings are reported for the association with asthma. Understanding PDAC risk factors will help us to implement appropriate strategies to prevent, treat and diagnose this cancer. This study assessed and characterised the association between PDAC and asthma and corroborated existing reports regarding the association between allergies and PDAC risk. DESIGN: Information about asthma and allergies was collated from 1297 PDAC cases and 1024 controls included in the PanGenEU case-control study. Associations between PDAC and atopic diseases were studied using multilevel logistic regression analysis. Meta-analyses of association studies on these diseases and PDAC risk were performed applying random-effects model. RESULTS: Asthma was associated with lower risk of PDAC (OR 0.64, 95% CI 0.47 to 0.88), particularly long-standing asthma (>=17 years, OR 0.39, 95% CI 0.24 to 0.65). Meta-analysis of 10 case-control studies sustained our results (metaOR 0.73, 95% CI 0.59 to 0.89). Nasal allergies and related symptoms were associated with lower risk of PDAC (OR 0.66, 95% CI 0.52 to 0.83 and OR 0.59, 95% CI 0.46 to 0.77, respectively). These results were supported by a meta-analysis of nasal allergy studies (metaOR 0.6, 95% CI 0.5 to 0.72). Skin allergies were not associated with PDAC risk. CONCLUSIONS: This study shows a consistent inverse association between PDAC and asthma and nasal allergies, supporting the notion that atopic diseases are associated with reduced cancer risk. These results point to the involvement of immune and/or inflammatory factors that may either foster or restrain pancreas carcinogenesis warranting further research to understand the molecular mechanisms driving this association.

Timing of enteral nutrition in acute pancreatitis: meta-analysis of individuals using a single-arm of randomised trials.

INTRODUCTION: In acute pancreatitis, enteral nutrition (EN) reduces the rate of complications, such as infected pancreatic necrosis, organ failure, and mortality, as compared to parenteral nutrition (PN). Starting EN within 24 h of admission might further reduce complications. METHODS: A literature search for trials of EN in acute pancreatitis was performed. Authors of eligible trials were requested to provide the data of all patients in the EN-arm of their trials. A meta-analysis of individual patient data was performed. The cohort of patients with EN was divided into patients receiving EN within 24 h or after 24 h of admission. Multivariable logistic regression, adjusting for predicted disease severity and trial, was used to study the effect of timing of EN on a composite endpoint of infected pancreatic necrosis, organ failure, or mortality. RESULTS: Observational data from 165 individuals from 8 randomised trials were obtained; 100 patients with EN within 24 h and 65 patients with EN after 24 h of admission. In the multivariable model, EN started within 24 h of admission compared to EN started after 24 h of admission, reduced the composite endpoint from 45% to 19% (adjusted odds ratio [OR] of 0.44; 95% confidence interval [CI] 0.20-0.96). Within the composite endpoint, organ failure was reduced from 42% to 16% (adjusted OR 0.42; 95% CI 0.19-0.94). CONCLUSIONS: In this meta-analysis of observational data from individuals with acute pancreatitis, starting EN within 24 h after hospital admission, compared with after 24 h, was associated with a reduction in complications.

Somatostatin for prevention of post-ERCP pancreatitis: a randomized, double-blind trial.

BACKGROUND AND STUDY AIMS: Meta-analyses suggest that an intravenous bolus or a high dose continuous infusion of somatostatin reduces the incidence of acute pancreatitis after endoscopic retrograde cholangiopancreatography (ERCP). Clinical guidelines, however, do not recommend this prophylaxis. The aim of this randomized, double-blind clinical trial was to evaluate the effect of somatostatin on the incidence of post-ERCP pancreatitis. PATIENTS AND METHODS: Patients undergoing ERCP at a single center were randomized to either intravenous bolus of somatostatin followed by a short (4-hour) continuous infusion, or to a similar placebo regimen. The primary outcome was post-ERCP pancreatitis, defined as abdominal pain with an amylase level at least three times higher than the upper limit of normality 24 hours after the ERCP and requiring admission for at least 2 days. RESULTS: A total of 510 patients were enrolled (255 patients per group) and all completed follow-up. The main indications for ERCP were choledocholithiasis (62 %), and biliary malignant stricture (31 %). Post-ERCP pancreatitis occurred in 19 patients (7.5 %) in the somatostatin group and 17 patients (6.7 %) in the placebo group (relative risk [RR] 1.12, 95 % confidence interval [95 %CI] 0.59 - 2.1; P = 0.73). The number of cases of moderate or severe acute pancreatitis was similar in the somatostatin (2.4 %) and the placebo (3.5 %) groups (RR 0.67, 95 %CI 0.24 - 1.85, P = 0.43). No side effects were observed related to the use of somatostatin. CONCLUSIONS: Administration of an intravenous bolus of somatostatin followed by a short continuous infusion does not reduce the incidence of post-ERCP pancreatitis. Clinical Trials.gov number: NCT01060826.

Common CFTR haplotypes and susceptibility to chronic pancreatitis and congenital bilateral absence of the vas deferens.

CFTR mutations enhance susceptibility for idiopathic chronic pancreatitis (ICP) and congenital bilateral absence of the vas deferens (CBAVD); however, it is unknown why CFTR heterozygotes are at increased disease risk. We recently showed that common CFTR variants are associated with aberrantly spliced transcripts. Here, we genotyped for common CFTR variants and tested for associations in two ICP (ICP-A: 126 patients, 319 controls; ICP-B: 666 patients, 1,181 controls) and a CBAVD population (305 patients, 319 controls). Haplotype H10 (TG11-T7-470V) conferred protection (ICP-A: OR 0.19, P<0.0001; ICP-B: OR 0.78, P = 0.06; CBAVD OR 0.08, P<0.001), whereas haplotype H3 (TG10-T7-470M) increased disease risk (ICP-A: OR 8.34, P = 0.003; ICP-B: OR 1.88, P = 0.007; CBAVD: OR 5.67, P = 0.01). The risk of heterozygous CFTR mutations carriers for ICP (OR 2.44, P<0.001) and CBAVD (OR 14.73, P<0.001) was fully abrogated by the H10/H10 genotype. Similarly, ICP risk of heterozygous p.Asn34Ser SPINK1 mutation carriers (OR 10.34, P<0.001) was compensated by H10/H10. Thus, common CFTR haplotypes modulate ICP and CBAVD susceptibility alone and in heterozygous CFTR and p.Asn34Ser mutation carriers. Determination of these haplotypes helps to stratify carriers into high- and low-risk subjects, providing helpful information for genetic counseling.

A multilayered post-GWAS assessment on genetic susceptibility to pancreatic cancer.

BACKGROUND: Pancreatic cancer (PC) is a complex disease in which both non-genetic and genetic factors interplay. To date, 40 GWAS hits have been associated with PC risk in individuals of European descent, explaining 4.1% of the phenotypic variance. METHODS: We complemented a new conventional PC GWAS (1D) with genome spatial autocorrelation analysis (2D) permitting to prioritize low frequency variants not detected by GWAS. These were further expanded via Hi-C map (3D) interactions to gain additional insight into the inherited basis of PC. In silico functional analysis of public genomic information allowed prioritization of potentially relevant candidate variants. RESULTS: We identified several new variants located in genes for which there is experimental evidence of their implication in the biology and function of pancreatic acinar cells. Among them is a novel independent variant in NR5A2 (rs3790840) with a meta-analysis p value = 5.91E-06 in 1D approach and a Local Moran's Index (LMI) = 7.76 in 2D approach. We also identified a multi-hit region in CASC8-a lncRNA associated with pancreatic carcinogenesis-with a lowest p value = 6.91E-05. Importantly, two new PC loci were identified both by 2D and 3D approaches: SIAH3 (LMI = 18.24), CTRB2/BCAR1 (LMI = 6.03), in addition to a chromatin interacting region in XBP1-a major regulator of the ER stress and unfolded protein responses in acinar cells-identified by 3D; all of them with a strong in silico functional support. CONCLUSIONS: This multi-step strategy, combined with an in-depth in silico functional analysis, offers a comprehensive approach to advance the study of PC genetic susceptibility and could be applied to other diseases.

Pancreatic Cancer Risk in Relation to Lifetime Smoking Patterns, Tobacco Type, and Dose-Response Relationships.

BACKGROUND: Despite smoking being a well-established risk factor for pancreatic cancer, there is a need to further characterize pancreatic cancer risk according to lifespan smoking patterns and other smoking features, such as tobacco type. Our aim was to deeply investigate them within a large European case-control study. METHODS: Tobacco smoking habits and other relevant information were obtained from 2,009 cases and 1,532 controls recruited in the PanGenEU study using standardized tools. Multivariate logistic regression analysis was performed to evaluate pancreatic cancer risk by smoking characteristics and interactions with other pancreatic cancer risk factors. Fractional polynomials and restricted cubic splines were used to test for nonlinearity of the dose-response relationships and to analyze their shape. RESULTS: Relative to never-smokers, current smokers [OR = 1.72; 95% confidence interval (95% CI), 1.39-2.12], those inhaling into the throat (OR = 1.48; 95% CI, 1.11-1.99) or chest (OR = 1.33; 95% CI, 1.12-1.58), and those using nonfiltered cigarettes (OR = 1.69; 95% CI, 1.10-2.61), were all at an increased pancreatic cancer risk. Pancreatic cancer risk was highest in current black tobacco smokers (OR = 2.09; 95% CI, 1.31-3.41), followed by blond tobacco smokers (OR = 1.43; 95% CI, 1.01-2.04). Childhood exposure to tobacco smoke relative to parental smoking was also associated with increased pancreatic cancer risk (OR = 1.24; 95% CI, 1.03-1.49). Dose-response relationships for smoking duration, intensity, cumulative dose, and smoking cessation were nonlinear and showed different shapes by tobacco type. Effect modification by family history of pancreatic cancer and diabetes was likely. CONCLUSIONS: This study reveals differences in pancreatic cancer risk by tobacco type and other habit characteristics, as well as nonlinear risk associations. IMPACT: This characterization of smoking-related pancreatic cancer risk profiles may help in defining pancreatic cancer high-risk populations.

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.

IL-6, IL-10 and TNFα do not improve early detection of post-endoscopic retrograde cholangiopancreatography acute pancreatitis: a prospective cohort study.

The most reliable indicators for post-ERCP acute pancreatitis are elevated amylase levels and abdominal pain 24 hours after ERCP. As ERCP is often performed on an outpatient basis, earlier diagnosis is important. We aimed to identify early predictors of post-ERCP pancreatitis. We prospectively analyzed IL-6, IL-10, TNFα, CRP, amylase and lipase before and 4 hours after ERCP, and studied their association with abdominal pain. We included 510 patients. Post-ERCP pancreatitis occurred in 36 patients (7.1%). IL-6, IL-10, TNFα and CRP were not associated with post-ERCP pancreatitis. Levels of amylase and lipase were higher in patients with pancreatitis (522 U/L and 1808 U/L vs. 78 U/L and 61 U/L, respectively; p < 0.001). A cut-off of 218 U/L for amylase (x2.2 ULN) and 355 U/L for lipase (x6 ULN) had a negative predictive value of 99.2% and 99.5%, respectively. Amylase and lipase present a good correlation (Pearson coefficient 0.912). Among 342 (67.1%) patients without abdominal pain at 4 hours, post-ERCP pancreatitis was diagnosed in 8 (2.3%). Only 4 of these patients presented amylase or lipase > 3 ULN. Amylase and lipase were the only markers of post-ERCP pancreatitis 4 hours after the procedure.

Genetic and epigenetic markers in the evaluation of pancreatic masses.

BACKGROUND: Methylation markers have shown promise in the early diagnosis of pancreatic carcinoma. The aim of this study was to assess the diagnostic utility of hypermethylation status of candidate genes in combination with KRAS mutation detection in the evaluation of pancreatic masses. EXPERIMENTAL DESIGN: Sixty-one fine needle aspirates of pancreatic masses (43 pancreatic adenocarcinomas and 18 chronic pancreatitis) were studied. Methylation status of HRH2, EN1, SPARC, CDH13 and APC were analysed using melting curve analysis after DNA bisulfite treatment. KRAS mutations were also analysed. RESULTS: The methylation panel had a sensitivity of 73% (27 of 37, CI 95% 56 to 86%) and a specificity of 100% whenever two or more promoters were found hypermethylated. KRAS mutations showed a sensitivity of 77% (33 of 43, CI 95% 62 to 88%) and a specificity of 100%. Both molecular analyses added useful information to cytology by increasing the number of informative cases. When genetic and epigenetic analyses were combined sensitivity was 84% (36 of 43 CI 95% 69 to 93%) maintaining a 100% specificity. CONCLUSIONS: Analysis of hypermethylation status of a panel of genes and KRAS mutation detection offer a similar diagnostic yield in the evaluation of pancreatic masses. The combined molecular analysis increases the number of informative cases without diminishing specificity.

Independent contribution of common CFTR variants to chronic pancreatitis.

OBJECTIVE: We have assessed whether CFTR gene has a major impact on chronic pancreatitis (CP) pathogenesis than that provided by the CFTR mutations. For this aim, we have evaluated clinical parameters, CFTR mutations, and 3 potential regulatory CFTR variants (coding single-nucleotide polymorphisms): c.1540A>G, c.2694T>G, and c.4521G>A. METHODS: CFTR gene analysis was performed in a cohort of 136 CP patients and 93 controls from Spanish population using current scanning techniques (single-strand conformation polymorphism/heteroduplex, denaturing gradient gel electrophoresis, and denaturing high-performance liquid chromatography) and direct sequencing. RESULTS: A higher frequency of CFTR mutations were observed in patients (39%) than in controls (15%; P < or = 0.001), differences being mostly attributable to the prevalence of the cystic fibrosis (CF)-causing mutations (P = 0.009). The analysis of variants has shown statistically significant differences between patients and controls for c.4521G>A (Pcorrected = 0.036). Furthermore, the multi-marker analysis revealed that the 1540A;2694G;4521A (AGA) haplotype was more prevalent in CP than controls (Pcorrected = 0.042). Remarkably, this association was unrelated to CF-causing mutations (P = 0.006). CONCLUSIONS: Our results corroborate the higher susceptibility of CF carriers to CP and, furthermore, suggest that the AGA haplotype could contribute to an increased risk in the development of CP irrespective of other CF-causing mutations.

The p.Arg258Gly mutation in intracellular loop 2 of CFTR is associated with CFTR-related disorders.

Missense mutations account for approximately 50% of the mutations described in the CFTR gene. However, their proportion is higher in CFTR-related disorders (CFTR-RD) than in cystic fibrosis (CF), suggesting a different mutational spectrum. The uncertainty surrounding many of these mutations prevents suitable genetic counseling. Thus, it is crucial to determine whether a missense mutation has clinical expression, and if it does, to then define the associated phenotype. Herein we have assessed the phenotype associated with the p.Arg258Gly (R258G) mutation, checking our cohorts of patients (CF and CFTR-RD) and control subjects (CF carriers, fertile males, and general population). We also performed in silico predictive studies on the possible consequences of this mutation at the protein level. Lastly, we exhaustively reviewed the literature on this mutation. To date, R258G has only been found in six patients: a French congenital bilateral absence of vas deferens patient, reported in 1995 and five unrelated subjects from our cohort of non-CF patients, described here. Based on these findings, we postulate that R258G is primarily a CFTR-RD-associated mutation.

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.