Serum Biomarkers of Nociceptive and Neuropathic Pain in Chronic Pancreatitis.

Debilitating abdominal pain is a common symptom affecting most patients with chronic pancreatitis (CP). There are multiple underlying mechanisms that contribute to CP-related pain, which makes successful treatment difficult. The identification of biomarkers for subtypes of pain could provide viable targets for nonopioid interventions and the development of mechanistic approaches to pain management in CP. Nineteen inflammation- and nociception-associated proteins were measured in serum collected from 358 subjects with definite CP enrolled in PROspective Evaluation of Chronic Pancreatitis for EpidEmiologic and Translational StuDies, a prospective observational study of pancreatitis in US adult subjects. First, serum levels of putative biomarkers were compared between CP subjects with and without pain. Only platelet-derived growth factor B (PDGF-B) stood out, with levels significantly higher in the CP pain group as compared to subjects with no pain. Subjects with pain were then stratified into 4 pain subtypes (Neuropathic, Nociceptive, Mixed, and Unclassified). A comparison of putative biomarker concentration among 5 groups (no pain and 4 pain subtypes) identified unique proteins that were correlated with pain subtypes. Serum transforming growth factor beta 1 (TGFß1) level was significantly higher in the Nociceptive pain group compared to the No pain group, suggesting that TGFß1 may be a biomarker for nociceptive pain. The Neuropathic pain only group was too small to detect statistical differences. However, glycoprotein 130 (GP130), a coreceptor for interleukin 6, was significantly higher in the Mixed pain group compared to the groups lacking a neuropathic pain component. These data suggest that GP130 may be a biomarker for neuropathic pain in CP. PERSPECTIVE: Serum TGFß1 and GP130 may be biomarkers for nociceptive and neuropathic CP pain, respectively. Preclinical data suggest inhibiting TGFß1 or GP130 reduces CP pain in rodent models, indicating that additional translational and clinical studies may be warranted to develop a precision medicine approach to the management of pain in CP.

Serum biomarkers for chronic pancreatitis pain patterns.

OBJECTIVES: Chronic pancreatitis (CP) is associated with debilitating refractory pain. Distinct subtypes of CP pain have been previously characterized based on severity (none, mild-moderate, severe) and temporal (none, intermittent, constant) nature of pain, but no mechanism-based tools are available to guide pain management. This exploratory study was designed to determine if potential pain biomarkers could be detected in patient serum and whether they associate with specific pain patterns. METHODS: Cytokines, chemokines, and peptides associated with nociception and pain were measured in legacy serum samples from CP patients (N = 99) enrolled in the North American Pancreatitis Studies. The unsupervised hierarchical cluster analysis was applied to cluster CP patients based on their biomarker profile. Classification and regression tree was used to assess whether these biomarkers can predict pain outcomes. RESULTS: The hierarchical cluster analysis revealed a subset of patients with predominantly constant, mild-moderate pain exhibited elevated interleukin-1ß (IL-1ß), interleukin-6 (IL-6), interleukin-2 (IL-2), tumor necrosis factor alpha (TNFα), and monocyte chemoattractant protein-1 (MCP1) whereas patients with higher interleukin-4 (IL-4), interleukin-8 (IL-8) and calcitonin gene related peptide (CGRP) were more likely to have severe pain. Interestingly, analyses of each individual biomarker revealed that patients with constant pain had reduced circulating TNFα and fractalkine. Patients with severe pain exhibited a significant reduction in TNFα as well as trends towards lower levels of IL-6 and substance P. DISCUSSION: The observations from this study indicate that unique pain experiences within the chronic pancreatitis population can be associated with distinct biochemical signatures. These data indicate that further hypothesis-driven analyses combining biochemical measurements and detailed pain phenotyping could be used to develop precision approaches for pain management in patients with chronic pancreatitis.

Assessment of Weight Loss and Gastrointestinal Symptoms Suggestive of Exocrine Pancreatic Dysfunction After Acute Pancreatitis.

INTRODUCTION: Studies evaluating the natural history of exocrine pancreatic dysfunction (EPD) after acute pancreatitis (AP) are sparse. This study aims to assess incidence and predictors of weight loss and gastrointestinal (GI) symptoms suggestive of EPD 12 months after an AP episode. METHODS: Patients enrolled in the Pancreatitis-associated Risk of Organ Failure Study at the time of an AP episode were included. Weight and GI symptom data were prospectively collected by self-report at enrollment and at 3- and 12-month (windows 2-7 and 8-20) telephone follow-ups. Multivariable logistic regression was used to assess factors associated with ≥10% total body weight loss (EPD surrogate) at 12 months. A generalized estimating equation was used to measure each factor's population effect (in pounds) over 12 months after AP. RESULTS: Follow-up at 12 months in 186 patients (median age = 54 years, 46% men, 45% biliary, 65% first AP attack) revealed weight loss ≥10% from baseline, occurring in 44 patients (24%). Risk of weight loss increased with higher baseline body mass index, previous diagnosis of diabetes mellitus, and worsening AP severity (all P < 0.010). GI symptoms were reported in 13/31 (42%) patients at 12 months. AP severity was independently associated with ≥10% weight loss at 12 months. Over 12 months, men lost more weight than women (average 9.5 lbs); patients with severe AP lost, on average, 14 lbs. DISCUSSION: Weight loss after AP occurs in one-quarter of patients and is associated with AP severity. EPD incidence after AP is likely underappreciated. Further work is needed to assess EPD and potential for pancreatic enzyme supplementation.

Unique circulating immune signatures for recurrent acute pancreatitis, chronic pancreatitis and pancreatic cancer: A pilot study of these conditions with and without diabetes.

OBJECTIVE: This exploratory study seeks to identify distinct circulating immune signatures among patients having recurrent acute pancreatitis (RAP), chronic pancreatitis (CP), and pancreatic adenocarcinoma (PDAC). METHODS: A retrospective analysis of human serum samples from collaborating institutions of the Consortium for the Study of Chronic Pancreatitis, Diabetes, and Pancreatic Cancer (CPDPC) was performed. Samples came from the North American Pancreatitis Studies 2 (NAPS2) cohort and the Pancreatic Adenocarcinoma Gene Environment Risk Study (PAGER) and were analyzed using a 62-plex Luminex assay in a blinded fashion. Group and pairwise comparisons were performed to identify unique immune signature panels and to calculate diagnostic utility using area under the curve analysis. RESULTS: A total of 179 patients' samples were included: 41 controls, 40 CP, 78 PDAC and 20 RAP patients, of which 20 controls, 20 CP, and 58 PDAC patients had diabetes mellitus (DM). A unique immune signature panel could discriminate RAP, CP, and PDAC from controls with an AUC range from 0.77 to 0.86 (95% CI range: 0.64-0.94), RAP from CP, and CP from PDAC with an AUC of 0.77 (95% CI 0.64-0.90) and 0.76 (95% CI 0.67-0.86), respectively. Furthermore, an immune signature panel could also discriminate PDAC-DM from DM controls with an AUC of 0.96 (95% CI: 0.93-1.00) CONCLUSION: This study identifies unique immune analytes that may serve as novel diagnostic and predictive non-invasive biomarkers of RAP, CP, and PDAC. Further validation is warranted in prospective cohorts as developed by the CPDPC.

Hereditary Pancreatitis in the United States: Survival and Rates of Pancreatic Cancer.

OBJECTIVES: Hereditary pancreatitis (HP), an autosomal dominant disease typically caused by mutations in PRSS1, has a broad range of clinical characteristics and high cumulative risk of pancreatic cancer. We describe survival and pancreatic cancer risk in the largest HP cohort in the US. METHODS: HP probands and family members prospectively recruited from 1995 to 2013 completed medical and family history questionnaires, and provided blood for DNA testing. Overall survival (until 12/31/2015) was determined from the Social Security Death Index (SSDI), National Death Index (NDI), and family members. Cause of death was obtained from the NDI. RESULTS: 217 PRSS1 carriers (181 symptomatic) formed the study cohort. The most frequently detected mutations were p.R122H (83.9%) and p.N29I (11.5%). Thirty-seven PRSS1 carriers (30 symptomatic, 7 asymptomatic) were deceased at conclusion of the study (5 from pancreatic cancer). Median overall survival was 79.3 years (IQR 72.2-85.2). Risk of pancreatic cancer was significantly greater than age- and sex- matched SEER data (SIR 59, 95% CI 19-138), and cumulative risk was 7.2% (95% CI 0-15.4) at 70 years. DISCUSSION: We confirm prior observations on survival and pancreatic cancer SIR in PRSS1 subjects. Although risk of pancreatic cancer was significantly high in these patients, its cumulative risk was much lower than previous reports.

The -251 A/T Polymorphism in the IL8 Promoter is a Risk Factor for Acute Pancreatitis.

OBJECTIVES: Inflammation in the setting of acute pancreatitis (AP) is partially driven by pathogen recognition receptors that recognize damage-associated molecular patterns. Interleukin (IL)-8 is a chemotactic factor produced by pathogen recognition receptor-expressing cells. A single-nucleotide polymorphism in IL8 promoter region (-251 A/T) has been implicated in inflammatory diseases. We examined whether this IL8 polymorphism confers susceptibility to AP. METHODS: Patients with AP (n = 357) were prospectively recruited. Clinical data and blood were collected in subjects and controls (n = 347). Severity was defined following the Revised Atlanta Classification. Genotypes were assessed by quantitative polymerase chain reaction using TaqMan probes. RESULTS: Patients and controls had similar demographics and had no difference in Hardy-Weinberg (patients, P = 0.29; controls, P = 0.66). Twenty-five percent of patients developed severe AP. Compared with controls, the A/A genotype was more common in AP (P = 0.041; odds ratio, 1.42; 95% confidence interval, 1-1.99). Obese patients with the A/A genotype were more likely to develop mild AP (P = 0.047). CONCLUSIONS: The -251 polymorphism confers susceptibility to AP and disease severity in obese patients. However, its effect is moderate. One potential mechanism for this susceptibility is via increased IL8 production by innate cells, with subsequent enhanced neutrophil influx and pancreatic injury.

Acute Pancreatitis Has a Long-term Deleterious Effect on Physical Health Related Quality of Life.

BACKGROUND & AIMS: It is not clear how acute pancreatitis (AP) affects health related quality of life (HRQOL). We aimed to determine the long-term independent effect of AP on physical and mental HRQOL. METHODS: We analyzed data from 91 patients (mean 52 years of age, 54% women) admitted with AP to the University of Pittsburgh Medical Center from 2011 to 2015 who responded to telephone surveys at a median of 14 months after hospital discharge (interquartile range, 12-16 months). Individuals who did not answer the telephone survey were sent a questionnaire by regular mail. Patients answered questions from the 12-Item Short-Form Survey, and answers were used to calculate mental component summary (MCS) and physical component summary (PCS) scores with norm-based scoring (normal ≥50). HRQOL for these subjects was compared with that of age- and sex-matched individuals without pancreatitis (1:2) identified from the North American Pancreatitis Study. We controlled for other covariates using multivariable regression analysis. RESULTS: At follow-up, individuals with AP had a significantly lower PCS score (46.2 ± 11.8) than did control subjects (51.1 ± 9.5; P < .01), but a similar MCS score. A 4-point reduction of the PCS was attributed to AP after controlling for sociodemographic factors and medical comorbidities. The only pancreatitis-related factor associated with low PCS score was multisystem organ failure. Presence of abdominal pain, analgesic use, disability, and current smoking at the time of follow-up were also associated with lower PCS scores. Etiology of AP, disease severity (by Revised Atlanta classification), use of nutritional support, and performance of pancreatic interventions did not affect HRQOL at follow-up. CONCLUSIONS: In a 14-month follow-up of patients hospitalized with AP, we found a meaningful, independent, and deleterious effect of AP in the physical HRQOL of these patients, compared to individuals without AP. Further research is needed to determine the duration of this impairment and to evaluate the effects of modifying risk factors.

The Common Chymotrypsinogen C (CTRC) Variant G60G (C.180T) Increases Risk of Chronic Pancreatitis But Not Recurrent Acute Pancreatitis in a North American Population.

OBJECTIVES: Recurrent acute pancreatitis (RAP) is a complex inflammatory disorder that may progress to fibrosis and other irreversible features recognized as chronic pancreatitis (CP). Chymotrypsinogen C (CTRC) protects the pancreas by degrading prematurely activated trypsinogen. Rare mutations are associated with CP in Europe and Asia. We evaluated the occurrence of CTRC variants in subjects with RAP, CP, and controls from the North American Pancreatitis Study II cohort. METHODS: CP (n=694), RAP (n=448), and controls (n=1017) of European ancestry were evaluated. Subgroup analysis included CFTR and SPINK1 variants, alcohol, and smoking. RESULTS: We identified previously reported rare pathogenic CTRC A73T, R254W, and K247_R254del variants, intronic variants, and G60G (c.180 C>T; rs497078). Compared with controls (minor allele frequency (MAF)=10.8%), c.180T was associated with CP (MAF=16.8%, P<0.00001) but not RAP (MAF=11.9% P=NS). Trend test indicated co-dominant risk for CP (CT odds ratio (OR)=1.36, 95% confidence interval (CI)=1.13-1.64, P=0.0014; TT OR=3.98, 95% CI=2.10-7.56, P<0.0001). The T allele was significantly more frequent with concurrent pathogenic CFTR variants and/or SPINK1 N34S (combined 22.9% vs. 16.1%, OR 1.92, 95% C.I. 1.26-2.94, P=0.0023) and with alcoholic vs. non-alcoholic CP etiologies (20.8% vs. 12.4%, OR=1.9, 95% CI=1.30-2.79, P=0.0009). Alcohol and smoking generally occurred together, but the frequency of CTRC c.180 T in CP, but not RAP, was higher among never drinkers-ever smokers (22.2%) than ever drinker-never smokers (10.8%), suggesting that smoking rather than alcohol may be the driving factor in this association. CONCLUSIONS: The common CTRC variant c.180T acts as disease modifier that promotes progression from RAP to CP, especially in patients with CFTR or SPINK1 variants, alcohol, or smoking.

TNF-alpha gene (TNFA) variants increase risk for multi-organ dysfunction syndrome (MODS) in acute pancreatitis.

BACKGROUND/OBJECTIVES: Acute pancreatitis (AP) is a complex inflammatory syndrome with unpredictable progression to systemic inflammation and multi-organ dysfunction syndrome (MODS). Tumor necrosis factor alpha (TNF-α) is a cytokine that may link inflammation to the systemic inflammatory response syndrome (SIRS), which usually precedes MODS. Small genetic cohort studies of the TNFA promoter in AP produced ambiguous results. We performed a comprehensive evaluation of TNFA promoter variants to assess both susceptibility to AP and risk of progression to MODS. METHODS: We prospectively ascertained 401 controls and 211 patients with AP that were assessed for persistent SIRS (>48 h) and MODS. MODS was defined as failure of ≥2 organ systems (cardiovascular, pulmonary, and/or renal) persisting more than 48 h. Subjects were genotyped by DNA sequencing and analyzed for SNPs at -1031 C/T (rs1799964), -863 A/C (rs1800630), -857 C/T (rs1799724), -308 A/G (rs1800629), and -238 A/G (rs361525). RESULTS: Twenty-three of 211 AP patients (11%) developed MODS. TNFA promoter variants were not associated with susceptibility to AP, but progression to MODS was associated with the minor allele at -1031C (56.5% vs. 32.4% P = 0.022, OR: 2.7; 95%CI: 1.12-6.51) and -863A (43.5% vs. 21.8% P = 0.022, OR: 2.76; 95%CI: 1.12-6.74). CONCLUSION: TNFA promoter variants do not alter susceptibility to AP, but rather the TNF-α expression-enhancing -1031C and -863A alleles significantly increased the risk of AP progression to MODS. These data, within the context of previous studies, clarify the risk of specific genetic variants in TNFA and therefore the role of TNF-α in the overall AP syndrome.