Fibrosis of the pancreas: the initial tissue damage and the resulting pattern

Preoperative stereotactic radiotherapy to prevent pancreatic fistula in high-risk patients undergoing pancreatoduodenectomy (FIBROPANC): prospective multicentre phase II single-arm trial

BACKGROUND

Postoperative pancreatic fistula is the main driver of morbidity and mortality after pancreatoduodenectomy. In high-risk patients, the rate of postoperative pancreatic fistula approaches 50%, whereas it is below 5% in patients with pancreatic cancer who receive neoadjuvant chemoradiotherapy. The aim of this study was to evaluate the safety, feasibility, and efficacy of preoperative stereotactic body radiotherapy on the pancreatic neck transection margin in high-risk patients undergoing pancreatoduodenectomy to prevent postoperative pancreatic fistula.

METHODS

In this prospective multicentre open-label single-arm trial (progressing from a safety run-in phase to a phase II design), patients undergoing pancreatoduodenectomy for neoplasms other than pancreatic ductal adenocarcinoma received a single preoperative stereotactic body radiotherapy dose of 12 Gy. Primary endpoints included safety (less than or equal to 15% grade 3-5 toxicity), feasibility (a significant change in pancreatic texture measured using a durometer), and efficacy (a 15% reduction in the grade B/C postoperative pancreatic fistula rate compared with patients from the Dutch Pancreatic Cancer Audit who were eligible but not included in this study). Secondary endpoints assessed tissue fibrosis (collagen density).

RESULTS

Overall, 38 patients were included, of whom 33 (87%) completed the study protocol and were included in the per-protocol analysis. The safety cut-off was met, with 3% grade 3-5 toxicity. Pancreatic tissue treated with stereotactic body radiotherapy showed increased firmness using a durometer (median of 47 (interquartile range 36-57) versus 37 (interquartile range 30-41) Shore OO units; P < 0.001) and a higher collagen density (median of 6.1% (interquartile range 4.4%-9.5%) versus 4.6% (interquartile range 2.5%-7.4%); P = 0.003). The grade B/C postoperative pancreatic fistula rate with stereotactic body radiotherapy was 57.6% (95% c.i. 41% to 74%), compared with 34% (95% c.i. 27% to 42%) in audit controls (P = 0.011).

CONCLUSION

Preoperative stereotactic body radiotherapy is safe in high-risk patients undergoing pancreatoduodenectomy and increases parenchymal firmness and fibrosis, but fails to show evidence of efficacy.

Extracellular volume fraction derived from dual-energy CT: a potential predictor for acute pancreatitis after pancreatoduodenectomy

OBJECTIVES

To investigate the value of extracellular volume (ECV) fraction and fat fraction (FF) derived from dual- energy CT (DECT) for predicting postpancreatectomy acute pancreatitis (PPAP) after pancreatoduodenectomy (PD).

METHODS

This retrospective study included patients who underwent DECT and PD between April 2022 and September 2022. PPAP was determined according to the International Study Group for Pancreatic Surgery (ISGPS) definition. Iodine concentration (IC) and FF of the pancreatic parenchyma were measured on preoperative DECT. The ECV fraction was calculated from iodine map images of the equilibrium phase. The independent predictors for PPAP were assessed by univariate and multivariable logistic regression analysis and receiver operating characteristic (ROC) curve analysis.

RESULTS

Sixty-nine patients were retrospectively enrolled (median age, 60 years; interquartile range, 55-70 years; 47 men). Of these, nine patients (13.0%) developed PPAP. These patients had lower portal venous phase IC, equilibrium phase IC, FF, and ECV fraction, and higher pancreatic parenchymal-to-portal venous phase IC ratio and pancreatic parenchymal-to-equilibrium phase IC ratio, compared with patients without PPAP. After multivariable analysis, ECV fraction was independently associated with PPAP (odd ratio [OR], 0.87; 95% confidence interval [CI]: 0.79, 0.96; p < 0.001), with an area under the curve (AUC) of 0.839 (sensitivity 100.0%, specificity 58.3%).

CONCLUSIONS

A lower ECV fraction is independently associated with the occurrence of PPAP after PD. ECV fraction may serve as a potential predictor for PPAP after PD.

CLINICAL RELEVANCE STATEMENT

DECT-derived ECV fraction of pancreatic parenchyma is a promising biomarker for surgeons to preoperatively identify patients with higher risk for postpancreatectomy acute pancreatitis after PD and offer selective perioperative management.

KEY POINTS

PPAP is a complication of pancreatic surgery, early identification of higher-risk patients allows for risk mitigation. Lower DECT-derived ECV fraction was independently associated with the occurrence of PPAP after PD. DECT aids in preoperative PAPP risk stratification, allowing for appropriate treatment to minimize complications.

3D histology reveals that immune response to pancreatic precancers is heterogeneous and depends on global pancreas structure

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal cancer for which few effective therapies exist. Immunotherapies specifically are ineffective in pancreatic cancer, in part due to its unique stromal and immune microenvironment. Pancreatic intraepithelial neoplasia, or PanIN, is the main precursor lesion to PDAC. Recently it was discovered that PanINs are remarkably abundant in the grossly normal pancreas, suggesting that the vast majority will never progress to cancer. Here, through construction of 48 samples of cm3-sized human pancreas tissue, we profiled the immune microenvironment of 1,476 PanINs in 3D and at single-cell resolution to better understand the early evolution of the pancreatic tumor microenvironment and to determine how inflammation may play a role in cancer progression. We found that bulk pancreatic inflammation strongly correlates to PanIN cell fraction. We found that the immune response around PanINs is highly heterogeneous, with distinct immune hotspots and cold spots that appear and disappear in a span of tens of microns. Immune hotspots generally mark locations of higher grade of dysplasia or locations near acinar atrophy. The immune composition at these hotspots is dominated by naïve, cytotoxic, and regulatory T cells, cancer associated fibroblasts, and tumor associated macrophages, with little similarity to the immune composition around less-inflamed PanINs. By mapping FOXP3+ cells in 3D, we found that regulatory T cells are present at higher density in larger PanIN lesions compared to smaller PanINs, suggesting that the early initiation of PanINs may not exhibit an immunosuppressive response. This analysis demonstrates that while PanINs are common in the pancreases of most individuals, inflammation may play a pivotal role, both at the bulk and the microscopic scale, in demarcating regions of significance in cancer progression.

Endoscopic Ultrasound Can Differentiate High-Grade Pancreatic Intraepithelial Neoplasia, Small Pancreatic Ductal Adenocarcinoma, and Benign Stenosis

Background/Aims

High-grade pancreatic intraepithelial neoplasia and invasive pancreatic ductal adenocarcinoma ≤10 mm are targets for early detection of pancreatic cancer. However, their imaging characteristics are unknown. We aimed to identify endoscopic ultrasound findings for the detection of these lesions.

Methods

Patients diagnosed with high-grade pancreatic intraepithelial neoplasia (n=29), pancreatic ductal adenocarcinoma ≤10 mm (n=11) (who underwent surgical resection), or benign main pancreatic duct stenosis (n=20) between January 2014 and January 2021 were retrospectively included. Six features differentiating these lesions were examined by endoscopic ultrasonography: main pancreatic duct stenosis, upstream main pancreatic duct dilation, hypoechoic areas surrounding the main pancreatic duct irregularities (mottled areas without demarcation or round areas with demarcation), branch duct dilation, prominent lobular segmentation, and atrophy. Interobserver agreement was assessed by two independent observers.

Results

Hypoechoic areas surrounding the main pancreatic duct irregularities were observed more frequently in high-grade pancreatic intraepithelial neoplasia (82.8%) and pancreatic ductal adenocarcinoma ≤10 mm (90.9%) than in benign stenosis (15.0%) (p<0.001). High-grade pancreatic intraepithelial neoplasia exhibited mottled hypoechoic areas more frequently (79.3% vs 18.9%, p<0.001), and round hypoechoic areas less frequently (3.4% vs 72.7%, p<0.001), than pancreatic ductal adenocarcinoma ≤10 mm. The sensitivity and specificity of hypoechoic areas for differentiating high-grade pancreatic intraepithelial neoplasia, pancreatic ductal adenocarcinoma ≤10 mm, and benign stenosis were both 85.0%, with moderate interobserver agreement.

Conclusions

The hypoechoic areas surrounding main pancreatic duct irregularities on endoscopic ultrasound may differentiate between high-grade pancreatic intraepithelial neoplasia, pancreatic ductal adenocarcinoma ≤10 mm, and benign stenosis (Trial Registration: UMIN Clinical Trials Registry (UMIN000044789).

Imaging Diagnosis and Management of Fistulas in Pancreatitis

Pancreatic fistula is a highly morbid complication of pancreatitis. External pancreatic fistulas result when pancreatic secretions leak externally into the percutaneous drains or external wound (following surgery) due to the communication of the peripancreatic collection with the main pancreatic duct (MPD). Internal pancreatic fistulas include communication of the pancreatic duct (directly or via intervening collection) with the pleura, pericardium, mediastinum, peritoneal cavity, or gastrointestinal tract. Cross-sectional imaging plays an essential role in the management of pancreatic fistulas. With the help of multiplanar imaging, fistulous tracts can be delineated clearly. Thin computed tomography sections and magnetic resonance cholangiopancreatography images may demonstrate the communication between MPD and pancreatic fluid collections or body cavities. Endoscopic retrograde cholangiography (ERCP) is diagnostic as well as therapeutic. In this review, we discuss the imaging diagnosis and management of various types of pancreatic fistulas with the aim to sensitize radiologists to timely diagnosis of this critical complication of pancreatitis.

A new method for treating chronic pancreatitis and preventing fibrosis using bioactive calcium silicate ion solution

Chronic pancreatitis (CP) is a multifactorial fibroinflammatory syndrome. At present, there is no effective way to treat it clinically. In this study, we proposed a new approach by application of a highly active calcium silicate ion solution derived from calcium silicate (CS) bioceramics, which effectively inhibited the development of CP. This bioceramic derived bioactive ionic solution mainly regulated pancreatic acinar cells (PACs), macrophages and pancreatic stellate cells (PSCs) by SiO32- ions to inhibit inflammation and fibrosis and promote acinar regeneration. The possible mechanism of the therapeutic effect of CS ion solution mainly includes the inhibition of PAC apoptosis by down-regulating the c-caspase3 signal pathway and promotion of the regeneration of PACs by up-regulating the WNT/β-catenin signaling pathway. In addition, the CS ion solution also effectively down-regulated the NF-κB signaling pathway to reduce macrophage infiltration and PAC inflammatory factor secretion, thereby reducing PSC mediated pancreatic fibrosis. This bioceramics-based ion solution provides a new idea for disease treatment using biomaterials, which may have the potential for the development of new therapy for CP.

Immune cell infiltration in the pancreas of type 1, type 2 and type 3c diabetes

The different types of diabetes differ in disease pathogenesis but share the impairment or loss of β-cell function leading to chronic hyperglycaemia. While immune cells are present throughout the whole pancreas in normality, their number and activation is increased in diabetes. Different patterns and composition of inflammation could be observed in type 1, type 2 and type 3c diabetes. Immune cells, pancreatic stellate cells and fibrosis were present in the islet microenvironment and could add to β-cell dysfunction and therefore development and progression of diabetes. First studies investigating the use of anti-inflammatory drugs demonstrate their ability to rescue remaining β-cell function and their potential benefit in diabetes treatment. This article provides an overview of immune cell infiltrates in different types of diabetes, highlights the knowledge of their impact on β-cell function and introduces the potential of immunomodulatory strategies.

Quantitative imaging predicts pancreatic fatty infiltration on routine CT examination

PURPOSE

The purpose of this study was to assess the performance of quantitative computed tomography (CT) imaging for detecting pancreatic fatty infiltration, using the results of histopathological analysis as reference.

MATERIALS AND METHODS

Sixty patients who underwent pancreatic surgery for a pancreatic tumor between 2016 and 2019 were retrospectively included. There were 33 women and 27 men with a mean age of 56 ± 12 (SD) years (age range: 18-79 years). Patients with dilatation of the main pancreatic duct, chronic pancreatitis, or preoperative treatment were excluded to prevent any bias in the radiological-pathological correlation. Pancreatic fatty infiltration was recorded at pathology. Pancreatic surface lobularity, pancreatic attenuation, visceral fat area, and subcutaneous fat area were derived from preoperative CT images. The performance for the prediction of fatty infiltration was assessed using area under receiver operating characteristic curve (AUC) and backward binary logistic regression analysis. Results were validated in a separate cohort of 34 patients (17 women; mean age, 50 ± 14 [SD] years; age range: 18-73).

RESULTS

A total of 28/60 (47%) and 17/34 (50%) patients had pancreatic fatty infiltration in the derivation and validation cohorts, respectively. In the derivation cohort, patients with pancreatic fatty infiltration had a significantly higher PSL (P < 0.001) and a lower pancreatic attenuation on both precontrast and portal venous phase images (P = 0.011 and 0.003, respectively), and higher subcutaneous fat area and visceral fat area (P = 0.010 and 0.007, respectively). Multivariable analysis identified pancreatic surface lobularity > 7.6 and pancreatic attenuation on portal venous phase images < 83.5 Hounsfield units as independently associated with fatty infiltration. The combination of these variables resulted in an AUC of 0.85 (95% CI: 0.74-0.95) and 0.83 (95% CI: 0.67-0.99) in the derivation and validation cohorts, respectively.

CONCLUSION

CT-based quantitative imaging accurately predicts pancreatic fatty infiltration.

Acinar cells and the development of pancreatic fibrosis

Pancreatic fibrosis is caused by excessive deposition of extracellular matrixes of collagen and fibronectin in the pancreatic tissue as a result of repeated injury often seen in patients with chronic pancreatic diseases. The most common causative conditions include inborn errors of metabolism, chemical toxicity and autoimmune disorders. Its pathophysiology is highly complex, including acinar cell injury, acinar stress response, duct dysfunction, pancreatic stellate cell activation, and persistent inflammatory response. However, the specific mechanism remains to be fully clarified. Although the current therapeutic strategies targeting pancreatic stellate cells show good efficacy in cell culture and animal models, they are not satisfactory in the clinic. Without effective intervention, pancreatic fibrosis can promote the transformation from pancreatitis to pancreatic cancer, one of the most lethal malignancies. In the normal pancreas, the acinar component accounts for 82% of the exocrine tissue. Abnormal acinar cells may activate pancreatic stellate cells directly as cellular source of fibrosis or indirectly via releasing various substances and initiate pancreatic fibrosis. A comprehensive understanding of the role of acinar cells in pancreatic fibrosis is critical for designing effective intervention strategies. In this review, we focus on the role of and mechanisms underlying pancreatic acinar injury in pancreatic fibrosis and their potential clinical significance.

Diffuse pancreatic parenchymal atrophy, an imaging finding predictive of the development of pancreatic ductal adenocarcinoma: A case-control study

Background and Aim

Pancreatic ductal adenocarcinoma (PDAC) is a lethal cancer, partly because its early detection is difficult. This study aimed to identify computed tomography (CT) findings associated with PDAC prior to diagnosis.

Methods

Past CT images were retrospectively collected from the PDAC group (n = 54) and the control group (n = 90). The following imaging findings were compared: pancreatic mass, main pancreatic duct (MPD) dilatation with or without cutoff, cyst, chronic pancreatitis with calcification, partial parenchymal atrophy (PPA), and diffuse parenchymal atrophy (DPA). In the PDAC group, CT findings were examined during the pre-diagnostic period and 6-36 months and 36-60 months before diagnosis. Multivariate analyses were performed using logistic regression.

Results

MPD dilatation with cutoff (P < 0.0001) and PPA (P = 0.023) were identified as significant imaging findings 6-36 months before diagnosis. DPA was identified as a novel imaging finding at 6-36 months (P = 0.003) and 36-60 months (P = 0.009) before diagnosis.

Conclusion

DPA, MPD dilatation with cutoff, and PPA were identified as imaging findings associated with pre-diagnostic PDAC.

Yttrium Oxide Nanoparticles Attenuate L-Arginine Induced Chronic Pancreatitis

In this work, we tested the efficacy of yttrium oxide nanoparticles (NY), a promising antioxidant and anti-inflammatory agent, in L-arginine (L-Arg) induced chronic pancreatitis (CP) model. The nanoparticles were characterized using multiple techniques including transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (pXRD), and Energy dispersive X-ray analysis (EDX). The rats were divided into three groups: normal control, L-Arg control, L-Arg + NY (1 mg/kg). We probed the mechanistic effects of the NY by ELISA, multiplex analysis of TGF-β pathway and inflammatory cytokines and immunoblotting. NY treatment significantly reduced pancreatic oxidative-nitrosative stress. In addition, NY intervention also reduced inflammatory cytokines and chemokines resulting in the inhibition of fibrosis signaling. Further, NY treatment suppressed the TGF-β signaling and epithelial-mesenchymal transition (EMT). We conclude that NY shows potential antioxidant, anti-inflammatory, and anti-fibrotic effects against CP and associated fibrosis.

Pancreatic fibrosis by extracellular volume fraction using Contrast-enhanced computed tomography and relationship with pancreatic cancer

PURPOSE

This study aimed to assess the relationship between pancreatic fibrosis measured by the extracellular volume fraction (ECV) using contrast-enhanced computed tomography (CT) and the histologic pancreatic fibrosis fraction and investigate the relationship between pancreatic fibrosis and pancreatic cancer.

METHOD

The study included 88 consecutive patients (48 males, 40 females; median age, 69 years; range, 17-89 years); 47 had pancreatic cancer, and 41 had other diseases. Fifty-two cases were evaluated pathologically for pancreatic fibrosis. The histologic pancreatic fibrosis fraction was quantified using image analysis software in nontumorous pancreatic tissue at the resection stump using 2-µm-thick Azan-stained slides. Two board-certified radiologists measured ECV in the pancreatic parenchyma at an estimated transection line. The correlation between histologic pancreatic fibrosis fraction and ECV was investigated, and whether the ECV value could be used as a biomarker for pancreatic cancer was investigated.

RESULTS

The histologic pancreatic fibrosis fraction was significantly correlated with the ECV (r = 0.64, P < 0.01). Pancreatic fibrosis evaluated by ECV was higher in pancreatic cancer patients than in other patients (P < 0.01). On receiver-operating characteristic curve analysis, the ECV had good diagnostic accuracy for the development of pancreatic cancer (cut-off value 32.8%; sensitivity 61.0%, specificity 85.1%). ECV was identified on multivariate analysis as an independent risk factor for pancreatic cancer (odds ratio 1.16; P < 0.01).

CONCLUSIONS

Extracellular volume fraction was strongly related to the histologic pancreatic fibrosis fraction, which was independently associated with pancreatic cancer. Thus, extracellular volume fraction is an imaging biomarker that reflects the progression of pancreatic fibrosis and may potentially help predict the development of pancreatic cancer, although further investigation will be needed.

Accuracy and clinical outcomes of pancreatic EUS-guided fine-needle biopsy in a consecutive series of 852 specimens

Background and Objectives:

Pancreatic EUS-guided fine needle biopsy (EUS-FNB) is increasingly used. Accuracy of EUS-FNB, particularly for benign diseases, utility of additional EUS-FNB if malignancy is suspected but initial diagnosis is inconclusive, and complication rate are not fully elucidated. We evaluated operating characteristics of EUS-FNB overall and for different diagnostic categories, value of additional EUS-FNB if malignancy is suspected but initial diagnosis is inconclusive, and frequency and type of complications.

Methods:

A retrospective tertiary single-center study including 852 consecutive pancreatic SharkCore EUS-FNBs from 723 patients between 2015 and 2020. EUS-FNB diagnoses were applied according to Papanicolaou Society's system and each category was further subcategorized.

Results:

Sufficient tissue cylinders for a histologic diagnosis were obtained in 93.4% (796/852). Accuracy was overall, for malignant, and benign entities 85.6% (confidence interval [CI]: 83.2%–87.9%), 88.3% (CI: 85.9%–90.4%), and 94% (CI: 92.2%–95.5%). Sensitivity and accuracy of EUS-FNB for autoimmune pancreatitis (AIP) (n = 15) was 83.3% (CI: 58.6%–96.4%) and 99.2% (CI: 98.3%–99.7%). Of patients in whom malignancy was suspected but initial EUS-FNB diagnosis was inconclusive, 7.3% (53/723) underwent one or two additional EUS-FNBs, and in 54.7% (29/53) of these, a malignant diagnosis was established. The frequency of hospitalization following EUS-FNB was 4.7%, with 0.2% (n = 2) incidents needing active intervention.

Conclusions:

We found a high accuracy of pancreatic EUS-FNB across all diagnostic categories including rare entities, such as AIP. In patients with a clinical suspicion of malignancy, additional EUS-FNB resulted in a conclusive diagnosis in more than half of cases. Complications necessitate hospitalization in almost 5%, but the majority are self-limiting.

IL11 Activates Pancreatic Stellate Cells and Causes Pancreatic Inflammation, Fibrosis and Atrophy in a Mouse Model of Pancreatitis

Interleukin-11 (IL11) is important for fibrosis and inflammation, but its role in the pancreas is unclear. In pancreatitis, fibrosis, inflammation and organ dysfunction are associated with pancreatic stellate cell (PSC)-to-myofibroblast transformation. Here, we show that IL11 stimulation of PSCs, which specifically express IL11RA in the pancreas, results in transient STAT3 phosphorylation, sustained ERK activation and PSC activation. In contrast, IL6 stimulation of PSCs caused sustained STAT3 phosphorylation but did not result in ERK activation or PSC transformation. Pancreatitis factors, including TGFβ, CTGF and PDGF, induced IL11 secretion from PSCs and a neutralising IL11RA antibody prevented PSC activation by these stimuli. This revealed an important ERK-dependent role for autocrine IL11 activity in PSCs. In mice, IL11 was increased in the pancreas after pancreatic duct ligation, and in humans, IL11 and IL11RA levels were elevated in chronic pancreatitis. Following pancreatic duct ligation, administration of anti-IL11RA to mice reduced pathologic (ERK, STAT, NF-κB) signalling, pancreatic atrophy, fibrosis and pro-inflammatory cytokine (TNFα, IL6 and IL1β) levels. This is the first description of IL11-mediated activation of PSCs, and the data suggest IL11 as a stromal therapeutic target in pancreatitis.

Stem bark of Fraxinus rhynchophylla ameliorates the severity of pancreatic fibrosis by regulating the TGF-β/Smad signaling pathway

Chronic pancreatitis (CP) is a pathological fibroinflammatory syndrome of the pancreas. Currently, there are no therapeutic agents available for treating CP-associated pancreatic fibrosis. Fraxinus rhynchophylla (FR) reportedly exhibits anti-inflammatory, antioxidative and antitumor activities. Although FR possesses numerous properties associated with the regulation of diverse diseases, the effects of FR on CP remain unknown. Herein, we examined the effects of FR on CP. For CP induction, mice were intraperitoneally administered cerulein (50 μg/kg) 6 times a day, 4 days per week for 3 weeks. FR extract (100 or 400 mg/kg) or saline (control group) was intraperitoneally injected 1 hour before the first cerulein injection. After 3 weeks, the pancreas was harvested for histological analysis. In addition, pancreatic stellate cells (PSCs) were isolated to examine the antifibrogenic effects and regulatory mechanisms of FR. Administration of FR significantly inhibited histological damage in the pancreas, increased pancreatic acinar cell survival, decreased PSC activation and collagen deposition, and decreased pro-inflammatory cytokines. Moreover, FR treatment inhibited the expression of fibrotic mediators, such as α-smooth muscle actin (α-SMA), collagen, fibronectin 1, and decreased pro-inflammatory cytokines in isolated PSCs stimulated with transforming growth factor (TGF)-β. Furthermore, FR treatment suppressed the phosphorylation of Smad 2/3 but not of Smad 1/5 in TGF-β-stimulated PSCs. Collectively, these results suggest that FR ameliorates pancreatic fibrosis by inhibiting PSC activation during CP.

The unfolded protein response: An emerging therapeutic target for pancreatitis and pancreatic ductal adenocarcinoma

Pancreatitis is a debilitating disease involving inflammation and fibrosis of the exocrine pancreas. Recurrent or chronic forms of pancreatitis are a significant risk factor for pancreatic ductal adenocarcinoma. While genetic factors have been identified for both pathologies, environmental stresses play a large role in their etiology. All cells have adapted mechanisms to handle acute environmental stress that alters energy demands. A common pathway involved in the stress response involves endoplasmic reticulum stress and the unfolded protein response (UPR). While rapidly activated by many external stressors, in the pancreas the UPR plays a fundamental biological role, likely due to the high protein demands in acinar cells. Despite this, increased UPR activity is observed in response to acute injury or following exposure to risk factors associated with pancreatitis and pancreatic cancer. Studies in animal and cell cultures models show the importance of affecting the UPR in the context of both diseases, and inhibitors have been developed for several specific mediators of the UPR. Given the importance of the UPR to normal acinar cell function, efforts to affect the UPR in the context of disease must be able to specifically target pathology vs. physiology. In this review, we highlight the importance of the UPR to normal and pathological conditions of the exocrine pancreas. We discuss recent studies suggesting the UPR may be involved in the initiation and progression of pancreatitis and PDAC, as well as contributing to chemoresistance that occurs in pancreatic cancer. Finally, we discuss the potential of targeting the UPR for treatment.

Association between pancreatic fibrosis and development of pancreoprivic diabetes after pancreaticoduodenectomy

This study investigated the correlation between pancreatic fibrosis (PF) and development of pancreoprivic diabetes after pancreaticoduodenectomy (PD). Ninety-five patients who underwent PD at Gangnam Severance Hospital between 2014 and 2017 were enrolled. PF grade was evaluated with alpha-smooth muscle actin (SMA) and Masson’s trichrome (TRC) staining. New-onset pancreoprivic diabetes and recurrence of disease were evaluated using fasting blood glucose measurement and radiography taken at 3-month intervals. Sixty-one patients did not have preoperative diabetes, however, 40 (65.6%) patients developed pancreoprivic diabetes after PD. High-grade PF was more common in the diabetes group than in the normal group (SMA, 42.5% vs. 28.6%, P = 0.747; TRC, 47.5% vs. 28.6%, P = 0.361). The 1-year cumulative incidence of hyperglycemia/pancreoprivic diabetes was higher with high-grade PF than low-grade PF (SMA, 94.4% vs. 73.0%, P = 0.027; TRC, 89.3% vs. 75.0%, P = 0.074). The SMA-TRC combined high-grade group had a higher proportion of primary pancreatic disease than the combined low-grade group (90.0% vs. 37.5%, P = 0.001). The 5-year disease-free survival of patients with pancreatic cancer was worse with high-grade PF than low-grade PF (SMA, 24.5% vs. 66.3%, P = 0.026; TRC, 23.6% vs. 58.4%, P = 0.047). In conclusion, patients with severe PF are more likely to develop pancreoprivic diabetes after PD and have worse disease-free survival.

Estimation of pancreatic fibrosis and prediction of postoperative pancreatic fistula using extracellular volume fraction in multiphasic contrast-enhanced CT

OBJECTIVE

To investigate the diagnostic performance of the extracellular volume (ECV) fraction in multiphasic contrast-enhanced computed tomography (CE-CT) for estimating histologic pancreatic fibrosis and predicting postoperative pancreatic fistula (POPF).

METHODS

Eighty-five patients (49 men; mean age, 69 years) who underwent multiphasic CE-CT followed by pancreaticoduodenectomy with pancreaticojejunal anastomosis between January 2012 and December 2018 were retrospectively included. The ECV fraction was calculated from absolute enhancements of the pancreas and aorta between the precontrast and equilibrium-phase images, followed by comparisons among histologic pancreatic fibrosis grades (F0‒F3). The diagnostic performance of the ECV fraction in advanced fibrosis (F2‒F3) was evaluated using receiver operating characteristic curve analysis. Multivariate logistic regression analysis was used to evaluate the associations of the risk of POPF development with patient characteristics, histologic findings, and CT imaging parameters.

RESULTS

The mean ECV fraction of the pancreas was 34.4% ± 9.5, with an excellent intrareader agreement of 0.811 and a moderate positive correlation with pancreatic fibrosis (r = 0.476; p < 0.001). The mean ECV fraction in advanced fibrosis was significantly higher than that in no/mild fibrosis (44.4% ± 10.8 vs. 31.7% ± 6.7; p < 0.001), and the area under the receiver operating characteristic curve for the diagnosis of advanced fibrosis was 0.837. Twenty-two patients (25.9%) developed clinically relevant POPF. Multivariate logistic regression analysis demonstrated that the ECV fraction was a significant predictor of POPF.

CONCLUSIONS

The ECV fraction can offer quantitative information for assessing pancreatic fibrosis and POPF after pancreaticojejunal anastomosis.

KEY POINTS

• There was a moderate positive correlation of the extracellular volume (ECV) fraction of the pancreas in contrast-enhanced CT with the histologic grade of pancreatic fibrosis (r = 0.476; p < 0.001). • The ECV fraction was higher in advanced fibrosis (F2‒F3) than in no/mild fibrosis (F0‒F1) (p < 0.001), with an AUC of 0.837 for detecting advanced fibrosis. • The ECV fraction was an independent risk factor for predicting subclinical (odds ratio, 0.81) and clinical (odds ratio, 0.80) postoperative pancreatic fistula.

The Potential Use of Cannabis in Tissue Fibrosis

Fibrosis is a condition characterized by thickening or/and scarring of various tissues. Fibrosis may develop in almost all tissues and organs, and it may be one of the leading causes of morbidity and mortality. It provokes excessive scarring that excels the usual wound healing response to trauma in numerous organs. Currently, very little can be done to prevent tissue fibrosis, and it is almost impossible to reverse it. Anti-inflammatory and immunosuppressive drugs are among the few treatments that may be efficient in preventing fibrosis. Numerous publications suggest that cannabinoids and extracts of Cannabis sativa have potent anti-inflammatory and anti-fibrogenic properties. In this review, we describe the types and mechanisms of fibrosis in various tissues and discuss various strategies for prevention and dealing with tissue fibrosis. We further introduce cannabinoids and their potential for the prevention and treatment of fibrosis, and therefore for extending healthy lifespan.

Pre-Operative Imaging and Pathological Diagnosis of Localized High-Grade Pancreatic Intra-Epithelial Neoplasia without Invasive Carcinoma

Pancreatic ductal adenocarcinoma (PDAC) arises from precursor lesions, such as pancreatic intra-epithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasm (IPMN). The prognosis of high-grade precancerous lesions, including high-grade PanIN and high-grade IPMN, without invasive carcinoma is good, despite the overall poor prognosis of PDAC. High-grade PanIN, as a lesion preceding invasive PDAC, is therefore a primary target for intervention. However, detection of localized high-grade PanIN is difficult when using standard radiological approaches. Therefore, most studies of high-grade PanIN have been conducted using specimens that harbor invasive PDAC. Recently, imaging characteristics of high-grade PanIN have been revealed. Obstruction of the pancreatic duct due to high-grade PanIN may induce a loss of acinar cells replaced by fibrosis and lobular parenchymal atrophy. These changes and additional inflammation around the branch pancreatic ducts (BPDs) result in main pancreatic duct (MPD) stenosis, dilation, retention cysts (BPD dilation), focal pancreatic parenchymal atrophy, and/or hypoechoic changes around the MPD. These indirect imaging findings have become important clues for localized, high-grade PanIN detection. To obtain pre-operative histopathological confirmation of suspected cases, serial pancreatic-juice aspiration cytologic examination is effective. In this review, we outline current knowledge on imaging characteristics of high-grade PanIN.

Guidelines on the histopathology of chronic pancreatitis. Recommendations from the working group for the international consensus guidelines for chronic pancreatitis in collaboration with the International Association of Pancreatology, the American Pancreatic Association, the Japan Pancreas Society, and the European Pancreatic Club

BACKGROUND

Chronic pancreatitis is a complex multifactorial fibro-inflammatory disease. Consensus guidelines are needed for the histopathological evaluation of non-autoimmune chronic pancreatitis (CP).

METHODS

An international working group with experts on the histopathology of CP evaluated 15 statements generated from evidence on seven key clinically relevant questions. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to evaluate the level of evidence available for each statement. To determine the level of agreement, the working group voted on the statements for strength of agreement, using a nine-point Likert scale, and Cronbach's alpha reliability coefficients were calculated.

RESULTS

Strong consensus was obtained for 12 statements relating to all seven key questions including that: the cardinal features of CP are the triad of fibrosis, loss of acinar tissue and duct changes; there are no unique histopathological features that distinguish the different aetiologies of CP; clinical history and laboratory investigations, including genetic testing, are important in establishing the aetiology of CP; there is no reproducible and universally accepted histological grading system for assessing severity of CP, although classification as "mild", "moderate" and "severe" is usually applied; scoring systems for fibrosis are not validated for clinical use; asymptomatic fibrosis is a common finding associated with ageing, and not necessarily evidence of CP; there are no obvious diagnostic macroscopic features of early CP; histopathology is not the gold standard for the diagnosis of CP; and cytology alone is not a reliable method for the diagnosis of CP.

CONCLUSIONS

Cardinal histopathological features of CP are well-defined and internationally accepted and pathological assessment is relevant for the purpose of differential diagnosis with other pancreatic diseases, especially cancer. However, a reliable diagnosis of CP requires integration of clinical, laboratory and imaging features and cannot be made by histology alone.

Cross-sectional imaging-based severity scoring of chronic pancreatitis: why it is necessary and how it can be done

Chronic pancreatitis (CP) remains a diagnostic challenge as clinical symptoms are non-specific, histopathological appearances are varied and pathogenesis remains incompletely understood. Multiple classifications and grading systems have been proposed for CP, but none leverage the full capabilities of cross-sectional imaging modalities and are not widely accepted or validated. CT and MRI/MRCP are useful in identifying a wide spectrum of histopathological changes in CP and can also assess exocrine reserve of pancreas. Advanced MRI techniques such as T1 mapping and extracellular volume fraction can potentially identify early CP. Cross-sectional imaging-based severity scoring can quantify CP disease burden and may have positive implications for clinicians and researchers. In this review, we discuss the need for cross-sectional imaging-based severity scoring for CP, role of CT, and MRI/MRCP in assessment of CP and how these modalities can be used to obtain severity scoring for CP. We summarize relevant information from recently published CT and MRI/MRCP reporting standards for CP, and from international guidelines for cross-sectional imaging and severity scoring for CP.

Pancreatic Stellate Cells: The Key Orchestrator of The Pancreatic Tumor Microenvironment

Pancreatic cancer is one of the most challenging adenocarcinomas due to its hostile molecular behavior and complex tumor microenvironment. It has been recently postulated that pancreatic stellate cells (PSCs), the resident lipid-storing cells of the pancreas, are important components of the tumor microenvironment as they can transdifferentiate into highly proliferative myofibroblasts in the context of tissue injury. Targeting tumor-stromal crosstalk in the tumor microenvironment has emerged as a promising therapeutic strategy against pancreatic cancer progression and metastasis. This chapter brings a broad view on the biological and pathological role of PSCs in the pancreas, activated stellate cells in the onset of tissue fibrosis, and tumor progression with particular emphasis on the bidirectional interactions between tumor cells and PSCs. Further, potential therapeutic regimens targeting activated PSCs in the pre-clinical and clinical trials are discussed.

Stromal heterogeneity in pancreatic cancer and chronic pancreatitis

BACKGROUND/OBJECTIVES

An abundant stromal reaction is a hallmark of pancreatic ductal adenocarcinoma (PDAC) and chronic pancreatitis (CP). The cells mainly responsible for the stromal reaction are activated pancreatic stellate cells (PSCs). Despite their crucial role, PSCs are not well characterized. PSCs share characteristics with the better-known hepatic stellate cells (HSCs). The aim of this study was a detailed analysis of PSCs in PDAC and CP.

METHODS

Whole-slide specimens of CP (n = 12) and PDAC (n = 10) were studied by histochemistry and immunohistochemistry. The stroma was evaluated using Movat's pentachrome stain. PSCs were tested by immunohistochemistry for PSC markers (α-SMA, CD34, desmin, NGFR, SPARC and tenascin C) and HSC markers (α-crystallin B, CD56, NGF, NT-3, synaptophysin and TrkC). Alpha-SMA, tenascin C, SPARC and NT-3 staining were verified on tissue micro arrays (TMAs) from a well-characterized cohort of 223 PDAC patients. PSCs isolated from human PDAC and CP tissue samples as well as HSCs were evaluated by immunofluorescence.

RESULTS

While the stroma of CP cases was characterized by a collagen-rich fibrosis, PDAC stroma displayed higher mucin content (p = 0.0002). PSCs showed variable expression of tested markers. In PDAC samples, staining of most markers was found around tumor complexes, while CP samples showed a greater variety of localizations. Alpha-SMA staining correlated with collagen-rich fibrosis (p = 0.012), while NT-3 staining correlated with mucin-rich stroma (p = 0.008). A peritumoral staining was confirmed for α-SMA, tenascin C, SPARC and NT-3 in the PDAC TMA cohort (n = 223). In a subgroup of patients with pancreatic head tumors and UICC 2009 IIB (n = 144), α-SMA staining intensity was a prognostic factor for overall survival at uni- and multivariate analysis (p = 0.036 and p = 0.002).

CONCLUSIONS

The close similarities between PSCs and HSCs were confirmed. Heterogeneous expression patterns of the tested markers might reflect different levels of activation or differentiation, or even multiple subpopulations of PSCs. Survival analysis suggests an impact of stromal composition on survival.

The ageing pancreas: a systematic review of the evidence and analysis of the consequences

Senior people constitute the fastest growing segment of the population. The elderly are at risk for malnutrition, thought to be caused by reduced food intake or involution of the physiological capacity of the GI tract. Age-related changes are well known in other secretory organs such as liver, kidney and intestine. The pancreas, representing a metabolically active organ with uptake and breakdown of essential nutritional components, changes its morphology and function with age. During childhood, the volume of the pancreas increases, reaching a plateau between 20 and 60 years, and declines thereafter. This decline involves the pancreatic parenchyma and is associated with decreased perfusion, fibrosis and atrophy. As a consequence of these changes, pancreatic exocrine function is impaired in healthy older individuals without any gastrointestinal disease. Five per cent of people older than 70 years and ten per cent older than 80 years have pancreatic exocrine insufficiency (PEI) with a faecal elastase-1 below 200 μg g-1 stool, and 5% have severe PEI with faecal elastase-1 below 100 μg g-1 stool. This may lead to maldigestion and malnutrition. Patients may have few symptoms, for example steatorrhoea, diarrhoea, abdominal pain and weight loss. Malnutrition consists of deficits of fat-soluble vitamins and is affecting both patients with PEI and the elderly. Secondary consequences may include decreased bone mineral density and results from impaired absorption of fat-soluble vitamin D due to impaired pancreatic exocrine function. The unanswered question is whether this age-related decrease in pancreatic function warrants therapy. Therapeutic intervention, which may consist of supplementation of pancreatic enzymes and/or vitamins in aged individuals with proven exocrine pancreas insufficiency, could contribute to healthy ageing.

The GDNF Family: A Role in Cancer?

The glial cell line-derived neurotrophic factor (GDNF) family of ligands (GFLs) comprising of GDNF, neurturin, artemin, and persephin plays an important role in the development and maintenance of the central and peripheral nervous system, renal morphogenesis, and spermatogenesis. Here we review our current understanding of GFL biology, and supported by recent progress in the area, we examine their emerging role in endocrine-related and other non-hormone-dependent solid neoplasms. The ability of GFLs to elicit actions that resemble those perturbed in an oncogenic phenotype, alongside mounting evidence of GFL involvement in tumor progression, presents novel opportunities for therapeutic intervention.

Histopathological changes in the pancreas of cattle with abdominal fat necrosis

The association between pancreatic disorder and abdominal fat necrosis in cattle remains unclear. The pancreases of 29 slaughtered cattle with or without fat necrosis were collected to investigate pathological changes. Japanese Black (JB) cattle were classified into the FN group (with abdominal fat necrosis; n=9) and N group (without fat necrosis; n=5). The pancreases were also collected from 15 Holstein Friesian (HF) cows. All JB cattle showed high body condition scores. Regarding the pathological findings, fatty pancreas which involves adipocyte infiltration into the pancreas and fat necrosis (saponification) were observed in 25 and 27 cases, respectively. Immunohistochemical staining with anti-Iba-1 antibody showed large numbers of macrophages surrounding the saponified fat in the pancreas. CD3-positive T cells were significantly more common in the pancreas of both the FN and N groups compared with the HF group (P<0.05). Furthermore, fibrosis in the pancreas exhibited a correlative tendency with the formation of necrotic fat mass in the peritoneal cavity (P<0.1). These results indicate that obesity leads to increased severity of pancreatic disorder, including fatty pancreas and pancreatitis. The pathological lesions in the pancreas may play a key role in abdominal fat necrosis through the inflammatory process.

Key players in pancreatic cancer-stroma interaction: Cancer-associated fibroblasts, endothelial and inflammatory cells

Pancreatic cancer (PC) is the most aggressive type of common cancers, and in 2014, nearly 40000 patients died from the disease in the United States. Pancreatic ductal adenocarcinoma, which accounts for the majority of PC cases, is characterized by an intense stromal desmoplastic reaction surrounding the cancer cells. Cancer-associated fibroblasts (CAFs) are the main effector cells in the desmoplastic reaction, and pancreatic stellate cells are the most important source of CAFs. However, other important components of the PC stroma are inflammatory cells and endothelial cells. The aim of this review is to describe the complex interplay between PC cells and the cellular and non-cellular components of the tumour stroma. Published data have indicated that the desmoplastic stroma protects PC cells against chemotherapy and radiation therapy and that it might promote the proliferation and migration of PC cells. However, in animal studies, experimental depletion of the desmoplastic stroma and CAFs has led to more aggressive cancers. Hence, the precise role of the tumour stroma in PC remains to be elucidated. However, it is likely that a context-dependent therapeutic modification, rather than pure depletion, of the PC stroma holds potential for the development of new treatment strategies for PC patients.

IVIM DW-MRI of autoimmune pancreatitis: therapy monitoring and differentiation from pancreatic cancer

OBJECTIVES

To evaluate IVIM DW-MRI for changes in IVIM-derived parameters during steroid treatment of autoimmune pancreatitis (AIP) and for the differentiation from pancreatic cancer (PC).

METHODS

Fifteen AIP-patients, 11 healthy patients and 20 PC-patients were examined with DWI-MRI using eight b-values (50, 100, 150, 200, 300, 400, 600, 800). 12 AIP-patients underwent follow-up examinations during treatment. IVIM-parameters and ADC800-values were tested for significant differences and an ROC analysis was performed.

RESULTS

The perfusion fraction f was significantly lower in patients with AIP at the time of diagnosis (10.5 ± 4.3 %) than in patients without AIP (20.7 ± 4.3 %). In AIP follow-up, f increased significantly to 17.1 ± 7.0 % in the first and 21.0 ± 4.1 % in the second follow up. In PC, the f-values were lower (8.2 ± 4.0 %, n.s.) compared to initial AIP and were significantly lower compared to first and second follow-up examination. In the ROC-analysis AUC-values for f were 0.63, 0.88 and 0.98 for differentiation of PC from initial, first and second follow up AIP-examination.

CONCLUSIONS

The found differences in f between AIP, AIP during steroid treatment and pancreatic cancer suggest that IVIM-diffusion MRI could serve as imaging biomarker during treatment in AIP-patients and as a helpful tool for differentiation between PC and AIP.

KEY POINTS

• MRI is used for follow-up examinations during therapy in AIP-patients • IVIM-DWI-MRI offers parameters which reflect perfusion and true diffusion • IVIM-parameters are helpful for differentiation between AIP and pancreatic cancer • IVIM-parameters could serve as an imaging biomarker during steroid treatment.

Sunflower Oil but Not Fish Oil Resembles Positive Effects of Virgin Olive Oil on Aged Pancreas after Life-Long Coenzyme Q Addition

An adequate pancreatic structure is necessary for optimal organ function. Structural changes are critical in the development of age-related pancreatic disorders. In this context, it has been reported that different pancreatic compartments from rats were affected according to the fat composition consumed. Since there is a close relationship between mitochondria, oxidative stress and aging, an experimental approach has been developed to gain more insight into this process in the pancreas. A low dosage of coenzyme Q was administered life-long in rats in order to try to prevent pancreatic aging-related alterations associated to some dietary fat sources. According to that, three groups of rats were fed normocaloric diets containing Coenzyme Q (CoQ) for two years, where virgin olive, sunflower, or fish oil was included as unique fat source. Pancreatic samples for microscopy and blood samples were collected at the moment of euthanasia. The main finding is that CoQ supplementation gives different results according to fat used in diet. When sunflower oil was the main fat in the diet, CoQ supplementation seems to improve endocrine pancreas structure and in particular β-cell mass resembling positive effects of virgin olive oil. Conversely, CoQ intake does not seem to improve the structural alterations of exocrine compartment previously observed in fish oil fed rats. Therefore CoQ may improve pancreatic alterations associated to the chronic intake of some dietary fat sources.

Evolution of pancreas in aging: degenerative variation or early changes of disease?

Pancreatic changes in aging have been described for many decades. They involve not only pancreatic parenchyma but also pancreatic ductal, microscopic, and exocrine functional changes. There have been many studies of these changes based on pathology and various imaging modalities, as well as functional studies. The pancreatic volume was found to decrease with advancing age, with a higher incidence of pancreatic steatosis, as demonstrated in autopsy and imaging studies. The pancreatic ductal structure has been described with wide ranges of normal variation, but many studies have shown a tendency toward enlargement with advancing age. By endoscopic ultrasound imaging, the aging pancreas may exhibit abnormal findings similar to chronic pancreatitis. Microscopically, there has been evidence of patchy lobular fibrosis and papillary hyperplasia and demonstrable k-ras mutation in both normal and dysplastic ductal mucosa. The evidence of pancreatic exocrine insufficiency has yielded conflicting results, but most studies have shown a tendency toward decreased pancreatic exocrine function in the elderly. Differentiating pancreatic change in the elderly from early chronic pancreatitis may be difficult as there are limited studies to compare these two conditions in terms of structural and functional changes.

Acinar cell-specific knockout of the PTHrP gene decreases the proinflammatory and profibrotic responses in pancreatitis

Pancreatitis is a necroinflammatory disease with acute and chronic manifestations. Accumulated damage incurred during repeated bouts of acute pancreatitis (AP) can lead to chronic pancreatitis (CP). Pancreatic parathyroid hormone-related protein (PTHrP) levels are elevated in a mouse model of cerulein-induced AP. Here, we show elevated PTHrP levels in mouse models of pancreatitis induced by chronic cerulein administration and pancreatic duct ligation. Because acinar cells play a major role in the pathophysiology of pancreatitis, mice with acinar cell-specific targeted disruption of the Pthrp gene (PTHrP(Δacinar)) were generated to assess the role of acinar cell-secreted PTHrP in pancreatitis. These mice were generated using Cre-LoxP technology and the acinar cell-specific elastase promoter. PTHrP(Δacinar) exerted protective effects in cerulein and pancreatic duct ligation models, evident as decreased edema, histological damage, amylase secretion, pancreatic stellate cell (PSC) activation, and extracellular matrix deposition. Treating acinar cells in vitro with cerulein increased IL-6 expression and NF-κB activity; these effects were attenuated in PTHrP(Δacinar) cells, as were the cerulein- and carbachol-induced elevations in amylase secretion. The cerulein-induced upregulation of procollagen I expression was lost in PSCs from PTHrP(Δacinar) mice. PTHrP immunostaining was elevated in human CP sections. The cerulein-induced upregulation of IL-6 and ICAM-1 (human acinar cells) and procollagen I (human PSCs) was suppressed by pretreatment with the PTH1R antagonist, PTHrP (7-34). These findings establish PTHrP as a novel mediator of inflammation and fibrosis associated with CP. Acinar cell-secreted PTHrP modulates acinar cell function via its effects on proinflammatory cytokine release and functions via a paracrine pathway to activate PSCs.

Quantitative analysis of diagnosing pancreatic fibrosis using EUS-elastography (comparison with surgical specimens)

BACKGROUND

An accurate diagnosis of pancreatic fibrosis is clinically important and may have potential for staging chronic pancreatitis. The aim of this study was to diagnose the grade of pancreatic fibrosis through a quantitative analysis of endoscopic ultrasound elastography (EUS-EG).

METHODS

From September 2004 to October 2010, 58 consecutive patients examined by EUS-EG for both pancreatic tumors and their upstream pancreas before pancreatectomy were enrolled. Preoperative EUS-EG images in the upstream pancreas were statistically quantified, and the results were retrospectively compared with postoperative histological fibrosis in the same area. For the quantification of EUS-EG images, 4 parameters (mean, standard deviation, skewness, and kurtosis) were calculated using novel software. Histological fibrosis was graded into 4 categories (normal, mild fibrosis, marked fibrosis, and severe fibrosis) according to a previously reported scoring system.

RESULTS

The fibrosis grade in the upstream pancreas was normal in 24 patients, mild fibrosis in 19, marked fibrosis in 6, and severe fibrosis in 9. Fibrosis grade was significantly correlated with all 4 quantification parameters (mean r = -0.75, standard deviation r = -0.54, skewness r = 0.69, kurtosis r = 0.67). According to the receiver operating characteristic analysis, the mean was the most useful parameter for diagnosing pancreatic fibrosis. Using the mean, the area under the ROC curves for the diagnosis of mild or higher-grade fibrosis, marked or higher-grade fibrosis and severe fibrosis were 0.90, 0.90, and 0.90, respectively.

CONCLUSIONS

An accurate diagnosis of pancreatic fibrosis may be possible by analyzing EUS-EG images.

Comparative analysis of pancreatic changes in aged rats fed life long with sunflower, fish, or olive oils

An adequate pancreatic structure is necessary for optimal organ function. Structural changes are critical in the development of age-related pancreatic disorders. We aimed to study the effect of oil consumption on pancreas histology in order to find aging-related signs. To this end, three groups of rats were fed an isocaloric diet for 2 years, where virgin olive, sunflower, or fish oil was included. Pancreatic samples for microscopy and blood samples were collected at the moment of sacrifice. As a result, the sunflower oil-fed rats presented higher β-cell numbers and twice the insulin content than virgin olive oil-fed animals. In addition, rats fed with fish oil developed acinar fibrosis and macrophage infiltrates in peri-insular regions, compared with counterparts fed with virgin olive oil. Inflammation signs were less prominent in the sunflower group. The obtained data emphasize the importance of dietary fatty acids in determining pancreatic structure.

Necro-inflammatory response of pancreatic acinar cells in the pathogenesis of acute alcoholic pancreatitis

The role of pancreatic acinar cells in initiating necro-inflammatory responses during the early onset of alcoholic acute pancreatitis (AP) has not been fully evaluated. We investigated the ability of acinar cells to generate pro- and anti-inflammatory mediators, including inflammasome-associated IL-18/caspase-1, and evaluated acinar cell necrosis in an animal model of AP and human samples. Rats were fed either an ethanol-containing or control diet for 14 weeks and killed 3 or 24 h after a single lipopolysaccharide (LPS) injection. Inflammasome components and necro-inflammation were evaluated in acinar cells by immunofluorescence (IF), histology, and biochemical approaches. Alcohol exposure enhanced acinar cell-specific production of TNFα, IL-6, MCP-1 and IL-10, as early as 3 h after LPS, whereas IL-18 and caspase-1 were evident 24 h later. Alcohol enhanced LPS-induced TNFα expression, whereas blockade of LPS signaling diminished TNFα production in vitro, indicating that the response of pancreatic acinar cells to LPS is similar to that of immune cells. Similar results were observed from acinar cells in samples from patients with acute/recurrent pancreatitis. Although morphologic examination of sub-clinical AP showed no visible signs of necrosis, early loss of pancreatic HMGB1 and increased systemic levels of HMGB1 and LDH were observed, indicating that this strong systemic inflammatory response is associated with little pancreatic necrosis. These results suggest that TLR-4-positive acinar cells respond to LPS by activating the inflammasome and producing pro- and anti-inflammatory mediators during the development of mild, sub-clinical AP, and that these effects are exacerbated by alcohol injury.

Correlation between secretin-enhanced MRCP findings and histopathologic severity of chronic pancreatitis in a cat model

BACKGROUND/OBJECTIVES

To evaluate the usefulness of secretin-enhanced magnetic resonance cholangiopancreatography (S-MRCP) in chronic pancreatitis (CP), we compared the severity of disease determined histopathologically with that indicated by S-MRCP imaging parameters in an induced CP cat model.

MATERIALS AND METHODS

An experimental group of randomly chosen cats (n = 24) underwent ligation of the pancreatic duct to induce CP, and cats in a similarly chosen control group (n = 8) were sham-operated. MRCP was performed prior to secretin stimulation, and 5 and 15 min afterward, noting in particular the pancreatic duct caliber change (PDC) and the increasing degree of fluid volume (IDFV). Histopathological changes were observed in pancreatic samples processed for hematoxylin-eosin and Sirius red staining, and CP was classified as normal, minimal, moderate, or advanced. Correlations were investigated between these groups and the PDC at 5 min and the IDFV at 15 min.

RESULTS

Between cats with minimal CP and the controls, the differences in mean IDFV and PDC were not significant although diseased cats showed a downward trend in both parameters. However, compared with the control group both the mean IDFV and PDC were significantly lower in cats with moderate (IDFV, P = 0.001; PDC, P = 0.013) or advanced (IDFV, P = 0.013; PDC, P = 0.001) CP.

CONCLUSION

The S-MRCP parameters IDFV and PDC correlated with the histopathological severity of induced CP. S-MRCP could be used to evaluate the severity of CP, although it is somewhat insensitive for depicting very early disease.

Pancreatitis activates pancreatic apelin-APJ axis in mice

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

Transient receptor potential ankyrin 1 mediates chronic pancreatitis pain in mice

Chronic pancreatitis (CP) is a devastating disease characterized by persistent and uncontrolled abdominal pain. Our lack of understanding is partially due to the lack of experimental models that mimic the human disease and also to the lack of validated behavioral measures of visceral pain. The ligand-gated cation channel transient receptor potential ankyrin 1 (TRPA1) mediates inflammation and pain in early experimental pancreatitis. It is unknown if TRPA1 causes fibrosis and sustained pancreatic pain. We induced CP by injecting the chemical agent trinitrobenzene sulfonic acid (TNBS), which causes severe acute pancreatitis, into the pancreatic duct of C57BL/6 trpa1(+/+) and trpa1(-/-) mice. Chronic inflammatory changes and pain behaviors were assessed after 2-3 wk. TNBS injection caused marked pancreatic fibrosis with increased collagen-staining intensity, atrophy, fatty replacement, monocyte infiltration, and pancreatic stellate cell activation, and these changes were reflected by increased histological damage scores. TNBS-injected animals showed mechanical hypersensitivity during von Frey filament probing of the abdomen, decreased daily voluntary wheel-running activity, and increased immobility scores during open-field testing. Pancreatic TNBS also reduced the threshold to hindpaw withdrawal to von Frey filament probing, suggesting central sensitization. Inflammatory changes and pain indexes were significantly reduced in trpa1(-/-) mice. In conclusion, we have characterized in mice a model of CP that resembles the human condition, with marked histological changes and behavioral measures of pain. We have demonstrated, using novel and objective pain measurements, that TRPA1 mediates inflammation and visceral hypersensitivity in CP and could be a therapeutic target for the treatment of sustained inflammatory abdominal pain.

MRI prediction of islet yield for autologous transplantation after total pancreatectomy for chronic pancreatitis

OBJECTIVE

The relationship between magnetic resonance imaging (MRI), histopathology, and islet yield was examined for chronic pancreatitis patients undergoing total pancreatectomy and autologous islet cell transplant (TP-AIT) to determine if the yield can be predicted by pre-operative MRI.

METHODS

MRI sequences and histopathology were scored and compared for patients from whom ≤2,500 islet equivalents/kg were obtained with those from whom >2,500 islet equivalents/kg were obtained.

RESULTS

Twenty patients, 14 female, mean age 40.20 ± 12.5 years, (range 19-63) underwent MRI before TP-AIT; mean 3,724 ± 891 islet equivalents/kg body weight, median 2,970, (range 76-17,770) were procured. There was no correlation between islet cell numbers and pancreas weight, HgbA1c, or c-peptide. The most common MRI sequence abnormality was the delayed interstitial phase, 14/18 (78 %). The other common MRI sequence abnormalities were, precontrast T1W 3D GRE sequence, 13/19 (68 %), and the arterial perfusion phase, 11/18 (61 %). The pancreatic duct was dilated in 10/20 (50 %). Parenchymal atrophy was noted in 10/20 (50 %). Median scores for individual MRI sequences were greater in patients with an islet cell yield of ≤2,500 islet equivalents/kg; for the delayed interstitial phase the difference was significant (median 2.5, range 1-3 versus median 0.5, range 0-3, P = 0.034). Histologically the most common feature was fibrosis, (17/17, 100 %); the score for fibrosis was greater for patients with an islet cell yield of ≤2,500 islet equivalents/kg (median 6.0, range 5-7 versus median 4.0, range 3-7, P = 0.024).

CONCLUSION

A diminished islet yield may be predicted on the basis of the delayed interstitial phase MRI sequence.

The impact of MFG-E8 in chronic pancreatitis: potential for future immunotherapy?

Background

The glycoprotein MFG-E8 mediates phagocytic clearance of apoptotic cells and influences the pathogenesis and progression of inflammatory diseases. MFG-E8 was shown to attenuate the progression of inflammation and to improve survival in septic rats. Accumulating evidence suggests an immunomodulatory link between MFG-E8 and the pro-inflammatory chemokine fractalkine, which may determine the severity of pain, fibrosis, and inflammation in chronic pancreatitis (CP).

Methods

The expression and localization of MFG-E8 was investigated in CP (n = 62), and normal pancreas (NP; n = 34) by QRT-PCR, Western-blot and immunohistochemistry analyses. Results were correlated with mRNA expression of fractalkine, CX3CR1, and with the presence and degree of pain and fibrosis. Human pancreatic stellate cells (hPSCs) were isolated from CP tissues and evaluated for MFG-E8 mRNA expression after fractalkine stimulation.

Results

MFG-E8-mRNA was significantly overexpressed in CP and isolated hPSCs when compared to NP. Western-blot and immunohistochemistry analysis confirmed accumulation of MFG-E8 in CP, with noticeably increased MFG-E8 immunoreactivity in tubular complexes. MFG-E8 expression correlated significantly with fractalkine expression, severe fibrosis, and the presence of pain in CP patients. Stimulation of hPSCs with fractalkine led to a significant increase in MFG-E8 expression.

Conclusions

In the present study, we demonstrated for the first time that MFG-E8 is significantly up-regulated in CP patients and together with fractalkine correlated noticeably with severe fibrosis and the presence of pain. hPSCs overexpress MFG-E8 upon fractalkine stimulation in vitro, which underlines the suggested immunmodulatory link in CP and may be a key mechanism in CP fibrogenesis and pain generation. Taken together, these novel findings suggest that MFG-E8 blockade may be a promising tool for future immunotherapy in CP to attenuate both fibrosis and pain sensation.

Chronic pancreatitis in dogs

Chronic pancreatitis used to be considered uncommon in dogs, but recent pathological and clinical studies have confirmed that it is in fact a common and clinically significant disease. Clinical signs can vary from low-grade recurrent gastrointestinal signs to acute exacerbations that are indistinguishable from classical acute pancreatitis. Chronic pancreatitis is a significant cause of chronic pain in dogs, which must not be underestimated. It also results in progressive impairment of endocrine and exocrine function and the eventual development of diabetes mellitus or exocrine pancreatic insufficiency or both in some affected dogs at end stage. The etiology is unknown in most cases. Chronic pancreatitis shows an increased prevalence in certain breeds, and recent work in English Cocker Spaniels suggests it is part of a polysystemic immune-mediated disease in this breed. The histological and clinical appearance is different in different breeds, suggesting that etiologies may also be different. Diagnosis is challenging because the sensitivities of the available noninvasive tests are relatively low. However, with an increased index of suspicion, clinicians will recognize more cases that will allow them to institute supportive treatment to improve the quality of life of the patient.

Clinical features and relapse rates after surgery in type 1 autoimmune pancreatitis differ from type 2: a study of 114 surgically treated European patients

BACKGROUND

At the recent consensus conference on autoimmune pancreatitis (AIP) in Honolulu, we presented preliminary data from our study of surgically treated AIP patients. Our data strongly supported the separation of AIP into type 1 and type 2. Our study is based on a total of 114 surgically treated European AIP patients. Our aims were to elucidate serum IgG4 elevation, other organ involvement, relapse of disease, steroid treatment and diabetes after surgery in 114 surgically treated European AIP patients.

METHODS

88 pancreaticoduodenectomies, 22 left-sided resections and 4 total pancreatectomies were examined. All cases were graded for granulocytic epithelial lesions, IgG4-positive cells, storiform fibrosis, phlebitis and eosinophilic granulocytes. Follow-up data were obtained from 102/114 patients, mean follow-up was 5.3 years.

RESULTS

Histologically, 63 (55.3%) of the 114 patients fulfilled the criteria of type 1 AIP, while 51 (44.7%) patients fulfilled the criteria of type 2 AIP. Type 1 AIP patients were older and more often males than type 2 AIP patients. Elevation of serum IgG4, involvement of extrapancreatic organs, disease relapse, systemic steroid treatment and diabetes after surgery were noted more often in type 1 AIP, while inflammatory bowel disease (IBD) was observed mainly in type 2 AIP.

CONCLUSIONS

Histological typing of AIP is clinically important because type 1 AIP is part of the IgG4-related disease and type 2 AIP is associated with IBD. Our data also show that relapse of disease and steroid treatment after surgery occur more frequently in type 1 than in type 2 AIP.

Progressive histopathological changes and β-cell loss in the pancreas of a new spontaneous rat model of type 2 diabetes

The eSMT rat is a new spontaneous model of type 2 diabetes that develops a progressive diabetic syndrome with a stronger incidence in males than in females. We decide to investigate the progression of the pancreatic histopathological changes during the lifespan of the eSMT rat, especially those associated with islet cell populations. Besides that, some plasmatic parameters were evaluated in order to correlate them with the morphological findings. Male eSMT and Sprague-Dawley control rats were used. The results showed a dramatic decrease of the volume density (VD) of endocrine tissue in the eSMT rats without evidence of insulitis. Islets became fragmented structures with strong presence of interstitial fibrosis. Consequently, plasma insulin levels showed a significant decrease, while plasma glucose, cholesterol and triglyceride levels were increased. Normal rats showed no significant changes in the VD of endocrine tissue, except for the older animals, where the VD of β-cell population was increased. Early derangements observed in islets, together with the progressive decrease of endocrine tissue and the metabolic disorders described, would be responsible for an irreversible pathologic condition which avoids the animal survival beyond about 18 months of age. However, there is still a need to investigate the causes of endocrine tissue decrease and its possible association with an inflammatory process that it could be associated with the development and progression of fibrosis.

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

SIGNIFICANCE

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

RECENT ADVANCES

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

CRITICAL ISSUES

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

FUTURE DIRECTIONS

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

Plasma TGF-β1, MMP-1 and MMP-3 Levels in Chronic Pancreatitis

Chronic pancreatitis (CP) presenting clinically with upper abdominal pain, as well as exocrine and endocrine insufficiencies, is characterized by irreversible morphological and functional alterations in the pancreas. The objective of the present study is to investigate the plasma levels of transforming growth factor-β 1 (TGF-β1), matrix metalloproteinases MMP-1 (collagenase) and MMP-3 (stromelysin) in CP. A total of 71 CP patients and 100 control subjects were considered for the study. Plasma levels of TGF-β1, MMP-1 and MMP-3 were determined by enzyme-linked immunosorbent assay in patients and control subjects. The plasma levels of TGF-β1 and MMP-1 were significantly elevated in patients compared to control group (*P = 0.0301, **P < 0.0001). However, there was no significant difference in the plasma levels of MMP-3 between patients and controls (P = 0.3756). The elevated levels of TGF-β1 and MMP-1 may influence the inflammatory reactions by enhancing the pancreatic stellate cell activation and deposition of extracellular matrix resulting in pancreatic fibrosis. Thus, the present study highlights the role of fibrogenic cytokine marker TGF-β1 and matrix metalloproteinases in the pathogenesis of CP.

Proteomic analysis of an immortalized mouse pancreatic stellate cell line identifies differentially-expressed proteins in activated vs nonproliferating cell states

Pancreatic stellate cells (PaSC) are mediators in chronic pancreatitis and pancreatic cancer pathogenesis. Proteins regulating the biomolecular pathways involved in the conversion of activated to quiescent PaSC may have a significant influence in the development of chronic pancreatitis. We aim to compare differentially expressed proteins from an immortalized cell line of mouse PaSC in the activated and serum-starved cell states using mass spectrometry-based proteomics. PaSC cultured in media supplemented with fetal bovine serum (FBS) proliferate in the activated state, while serum starvation promotes the cellular transition to a "pseudo-quiescent" state. Using these two cell states, we performed a comparative mass spectrometry (GeLC-MS/MS) proteomic analysis. We identified over 2000 nonredundant proteins in PaSC. Qualitative and label-free quantitative analysis revealed several hundred proteins that were differentially abundant between the cell states. Proteins that were more abundant in activated PaSC included cytoskeletal proteins and ribosomal proteins, while those more abundant in pseudoquiescent PaSC included proteins involved in protein degradation-related pathways (lysosome, ubiquitin-mediated proteolysis, and the proteasome). Investigation of the role of PaSC in the pathogenesis of chronic pancreatitis using the mass spectrometry-based proteomics strategy described herein will lead to further insights into the molecular mechanisms associated with the disease.