Integrated Physiology of the Exocrine and Endocrine Compartments in Pancreatic Diseases: Workshop Proceedings

The Integrated Physiology of the Exocrine and Endocrine Compartments in Pancreatic Diseases workshop was a 1.5-day scientific conference at the National Institutes of Health (Bethesda, MD) that engaged clinical and basic science investigators interested in diseases of the pancreas. This report provides a summary of the proceedings from the workshop. The goals of the workshop were to forge connections and identify gaps in knowledge that could guide future research directions. Presentations were segregated into six major theme areas, including 1) pancreas anatomy and physiology, 2) diabetes in the setting of exocrine disease, 3) metabolic influences on the exocrine pancreas, 4) genetic drivers of pancreatic diseases, 5) tools for integrated pancreatic analysis, and 6) implications of exocrine-endocrine cross talk. For each theme, multiple presentations were followed by panel discussions on specific topics relevant to each area of research; these are summarized here. Significantly, the discussions resulted in the identification of research gaps and opportunities for the field to address. In general, it was concluded that as a pancreas research community, we must more thoughtfully integrate our current knowledge of normal physiology as well as the disease mechanisms that underlie endocrine and exocrine disorders so that there is a better understanding of the interplay between these compartments.

Integrated Physiology of the Exocrine and Endocrine Compartments in Pancreatic Diseases: Workshop Proceedings

The "Integrated Physiology of the Exocrine and Endocrine Compartments in Pancreatic Diseases" Workshop was a 1.5-day scientific conference at the National Institutes of Health (Bethesda, MD) that engaged clinical and basic science investigators interested in diseases of the pancreas. This report summarizes the workshop proceedings. The goal of the workshop was to forge connections and identify gaps in knowledge that could guide future research directions. Presentations were segregated into 6 major themes, including (a) Pancreas Anatomy and Physiology; (b) Diabetes in the Setting of Exocrine Disease; (c) Metabolic Influences on the Exocrine Pancreas; (d) Genetic Drivers of Pancreatic Diseases; (e) Tools for Integrated Pancreatic Analysis; and (f) Implications of Exocrine-Endocrine Crosstalk. For each theme, there were multiple presentations followed by panel discussions on specific topics relevant to each area of research; these are summarized herein. Significantly, the discussions resulted in the identification of research gaps and opportunities for the field to address. In general, it was concluded that as a pancreas research community, we must more thoughtfully integrate our current knowledge of the normal physiology as well as the disease mechanisms that underlie endocrine and exocrine disorders so that there is a better understanding of the interplay between these compartments.

HGF/c-Met pathway inhibition combined with chemotherapy increases cytotoxic T-cell infiltration and inhibits pancreatic tumour growth and metastasis

Pancreatic cancer (PC) is a deadly cancer with a high mortality rate. The unique characteristics of PC, including desmoplasia and immunosuppression, have made it difficult to develop effective treatment strategies. Pancreatic stellate cells (PSCs) play a crucial role in the progression of the disease by interacting with cancer cells. One of the key mediators of PSC - cancer cell interactions is the hepatocyte growth factor (HGF)/c-MET pathway. Using an immunocompetent in vivo model of PC as well as in vitro experiments, this study has shown that a combined approach using HGF/c-MET inhibitors to target stromal-tumour interactions and chemotherapy (gemcitabine) to target cancer cells effectively decreases tumour volume, EMT, and stemness, and importantly, eliminates metastasis. Notably, HGF/c-MET inhibition decreases TGF-β secretion by cancer cells, resulting in an increase in cytotoxic T-cell infiltration, thus contributing to cancer cell death in tumours. HGF/c-MET inhibition + chemotherapy was also found to normalise the gut microbiome and improve gut microbial diversity. These findings provide a strong platform for assessment of this triple therapy (HGF/c-MET inhibition + chemotherapy) approach in the clinical setting.

An Orthotopic Resectional Mouse Model of Pancreatic Cancer

There is a lack of satisfactory animal models to study adjuvant and/or neoadjuvant therapy in patients being considered for surgery of pancreatic cancer (PC). To address this deficiency, we describe a mouse model involving orthotopic implantation of PC followed by distal pancreatectomy and splenectomy. The model has been demonstrated to be safe and suitably flexible for the study of various therapeutic approaches in adjuvant and neo adjuvant settings. In this model, a pancreatic tumor is first generated by implanting a mixture of human pancreatic cancer cells (luciferase-tagged AsPC-1) and human cancer associated pancreatic stellate cells into the distal pancreas of Balb/c athymic nude mice. After three weeks, the cancer is resected by re-laparotomy, distal pancreatectomy and splenectomy. In this model, bioluminescence imaging can be used to follow the progress of cancer development and effects of resection/treatments. Following resection, adjuvant therapy can be given. Alternatively, neoadjuvant treatment can be given prior to resection. Representative data from 45 mice are presented. All mice underwent successful distal pancreatectomy/splenectomy with no issues of hemostasis. A macroscopic proximal pancreatic margin greater than 5 mm was achieved in 43 (96%) mice. The technical success rate of pancreatic resection was 100%, with 0% early mortality and morbidity. None of the animals died during the week after resection. In summary, we describe a robust and reproducible technique for a surgical resection model of pancreatic cancer in mice which mimics the clinical scenario. The model may be useful for the testing of both adjuvant and neoadjuvant treatments.

Proteomic profiling of small extracellular vesicles derived from mouse pancreatic cancer and stellate cells: Role in pancreatic cancer

Small extracellular vesicles (sEVs) are cell-derived vesicles evolving as important elements involved in all stages of cancers. sEVs bear unique protein signatures that may serve as biomarkers. Pancreatic cancer (PC) records a very poor survival rate owing to its late diagnosis and several cancer cell-derived proteins have been reported as candidate biomarkers. However, given the pivotal role played by stellate cells (PSCs, which produce the collagenous stroma in PC), it is essential to also assess PSC-sEV cargo in biomarker discovery. Thus, this study aimed to isolate and characterise sEVs from mouse PC cells and PSCs cultured alone or as co-cultures and performed proteomic profiling and pathway analysis. Proteomics confirmed the enrichment of specific markers in the sEVs compared to their cells of origin as well as the proteins that are known to express in each of the culture types. Most importantly, for the first time it was revealed that PSC-sEVs are enriched in proteins (including G6PI, PGAM1, ENO1, ENO3, and LDHA) that mediate pathways related to development of diabetes, such as glucose metabolism and gluconeogenesis revealing a potential role of PSCs in pancreatic cancer-related diabetes (PCRD). PCRD is now considered a harbinger of PC and further research will enable to identify the role of these components in PCRD and may develop as novel candidate biomarkers of PC.

Asian-Oceanic Pancreatic Association: conception to actuality

The Asian-Oceanic Pancreatic Association (AOPA) was organized on July 22, 2005 with the purpose of promoting communication, scholarship, and scientific collaboration, as well as the exchange of knowledge in both basic and clinical research and education in Asian and Oceanic countries. The society will host biennial scientific meetings during the Asian Pacific Digestive Week (APDW) and members consist of individuals rather than regional societies. Given the diversity of its members, English was selected as the common language of communication to facilitate the exchange of ideas. The first AOPA symposium, which aimed to describe the pancreatology in various regions, was held in conjunction with the 60th Annual Meeting of the Japan Society of Gastroenterological Surgery (JSGS). The second scientific meeting will be held during APDW 2007.

Spatial profiling of endoplasmic reticulum stress markers in tumor associated cells predicts patient outcomes in pancreatic cancer

INTRODUCTION

The impact of endoplasmic reticulum (ER) stress in tumor-associated cells, such as cancer associated fibroblasts (CAFs), immune cells and endothelial cells, on patient outcomes in clinical specimens have not been examined. For the first time, we characterized the expression and spatial locations of ER stress markers, BiP and CHOP, in tumor-associated cells and assessed their prognostic significance in a panel of pancreatic ductal adenocarcinoma (PDAC) patient samples.

METHODS

Multiplex immunofluorescence was performed on tumor microarrays and images were analyzed using HALO AI software.

RESULTS

BiP and CHOP were upregulated in CAFs and endothelial cells in PDAC sections relative to non-neoplastic pancreas sections. High BiP expression in CAFs and endothelial cells was associated with greater vascular invasion and in immune cells was correlated with increased tumor size. High CHOP expression in immune cells correlated with poor patient survival. CAFs and immune cells were more likely to express BiP or CHOP when located close (< 20 μm) to tumor cells. High expression of CHOP in CAFs close to tumor cells correlated with improved patient survival.

CONCLUSION

For the first time, this study demonstrated that ER stress occurs in CAFs and immune cells predominantly in proximity to tumor cells in PDAC patient tissue. The correlation of high ER stress in immune cells with poor patient survival highlights the importance of the TME and the use of spatial analysis for the identification of novel biomarkers.

A journey to and with the stars: The pancreatic stellate cell story

The George E Palade Prize is the highest honour awarded by the International Association of Pancreatology, that recognises an individual who has made outstanding contributions to the understanding of the pancreas and pancreatic diseases. The 2023 Palade Prize was awarded to Professor Minoti Apte, University of New South Wales Sydney on September 16, 2023 during the Joint Meeting of the International Association of Pancreatology and the Indian Pancreas Club, held in Delhi, India. This paper summarises her Palade lecture wherein she reflects on her journey as a medical graduate, an academic and a researcher, with a particular focus on her team's pioneering work on pancreatic stellate cell biology and the role of these cells in health and disease. While there has been much progress in this field with the efforts of researchers worldwide, there is much still to be learned; thus it is a topic with ample scope for innovative research with the potential to translate into better outcomes for patients with pancreatic disease.

Fatty acid ethyl esters increase rat pancreatic lysosomal fragility

Recent studies indicate that altered lysosomal function may be involved in the early stages of pancreatic injury. Chronic consumption of ethanol has been shown to increase rat pancreatic lysosomal fragility. Fatty acid ethyl esters (nonoxidative products of ethanol metabolism) accumulate in the pancreas after ethanol consumption. The aim of this study was to determine whether the lysosomal fragility observed after ethanol could be mediated by fatty acid ethyl esters. Rat pancreatic lysosomes were incubated for 20 minutes at 20 degrees C with ethyl oleate (a representative fatty acid ethyl ester). Lysosomal stability was then assessed by determination of (1) latency (i.e., the percent increase in lysosomal enzyme activity after addition of Triton X-100) and (2) supernatant activity (i.e., the proportion of lysosomal enzyme remaining in the supernatant after resedimentation of lysosomes). N-acetyl glucosaminidase and cathepsin B were assayed as lysosomal marker enzymes. Lysosomes incubated with buffer alone were used as controls. Ethyl oleate at concentrations above 140 mumol/L increased pancreatic lysosomal fragility as demonstrated by decreased latency. Increased percentage of enzyme in the supernatant was observed at higher concentrations. These results suggest that increased pancreatic lysosomal fragility observed with ethanol may be mediated by fatty acid ethyl esters.

Both ethanol consumption and protein deficiency increase the fragility of pancreatic lysosomes

Both ethanol abuse and protein deficiency result in pancreatic injury. Moreover, these two variables frequently coexist. As lysosomal enzymes may play a role in the initiation of pancreatic injury, the aim of this study was to determine the effects of ethanol consumption and protein deficiency on pancreatic lysosomal stability. For 3 weeks, male Sprague-Dawley rats were match-fed (in groups of four) isocaloric amounts of one of the following liquid diets: (1) protein-sufficient diet, (2) protein-sufficient diet containing ethanol as 36% of the total energy, (3) protein-deficient diet, and (4) protein-deficient diet containing ethanol as 36% of energy. Pancreatic lysosomal stability was assessed by determining (a) latency, as indicated by the percentage increase in lysosomal enzyme activity in pancreatic homogenate induced by Triton X-100, and (b) by the percentage of lysosomal enzyme remaining in the supernatant after sedimentation of the lysosomal pellet from the pancreatic homogenate. Protein deficiency was associated with a decrease in latency and an increase in supernatant enzyme. Ethanol administration was associated with a decreased latency. Both protein-deficient and ethanol-fed animals exhibited higher pancreatic activities of cathepsin B, a lysosomal protease capable of activating trypsinogen. In addition, protein-deficient animals exhibited higher pancreatic activities of acid phosphatase, N-acetyl-glucosaminidase, and beta-glucuronidase. As lysosomal enzymes are postulated to play a role in the initiation of pancreatitis, these results suggest that ethanol consumption and protein deficiency may at least partly exert their toxic effects on the pancreas by altering pancreatic lysosomal stability and increasing the glandular content of cathepsin B.

The epidemiology of acute pancreatitis in Tasmania over a 12-year period: Is this a disease of disadvantage?

BACKGROUND

The global incidence of acute pancreatitis (AP) is increasing, but little information exists about trends in Australia. This study aimed to describe incidence trends, along with clinical and socio-demographic associations, in the state of Tasmania over a recent 12-year period.

METHODS

The study cohort was obtained by linking clinical and administrative datasets encompassing the whole Tasmanian population between 2007 and 2018, inclusive. Pancreatitis case definition was based on relevant ICD-10 hospitalization codes, or elevated serum lipase or amylase in pathology data. Age-standardised incidence rates were estimated, overall and stratified by sex, aetiology, and Index of Relative Socio-economic Disadvantage (IRSD).

RESULTS

In the study period, 4905 public hospital AP episodes were identified in 3503 people. The age-standardised person-based incidence rate across the entire period was 54 per 100,000 per year. Incidence was inversely related to IRSD score; 71 per 100,000 per year in the most disadvantaged quartile compared to 32 in the least disadvantaged. Biliary AP incidence was higher than that of alcohol-related AP, although the greatest incidence was in "unspecified" cases. There was an increase in incidence for the whole cohort (average annual percent change 3.23 %), largely driven by the two most disadvantaged IRSD quartiles; the least disadvantaged quartile saw a slight overall decrease.

CONCLUSION

This is the first Australian study providing robust evidence that AP incidence is increasing and is at the upper limit of population-based studies worldwide. This increased incidence is greatest in socio-economically disadvantaged areas, meriting further research to develop targeted, holistic management strategies.

Ethanol-induced alterations in messenger RNA levels correlate with glandular content of pancreatic enzymes

Ethanol abuse is a well-known association of pancreatitis. The effects of chronic ethanol consumption on pancreatic digestive and lysosomal enzymes may be relevant to the pathogenesis of alcoholic pancreatitis, because pancreatic enzymes play an important role in the development of pancreatic injury. The aims of this study were to determine the effects of ethanol on gene expression and glandular content of pancreatic digestive enzymes and on gene expression of the lysosomal enzyme cathepsin B (known to be capable of activating trypsinogen). Pancreatic content and mRNA levels for lipase, trypsinogen, and chymotrypsinogen were determined in rats that were pair-fed a nutritionally adequate liquid diet with or without ethanol for 4 weeks. mRNA levels for the lysosomal enzyme cathepsin B were also assessed in this model. Ethanol significantly increased the content of lipase in the pancreas. There was a trend toward an increase in trypsinogen and chymotrypsinogen levels; however, these differences were not statistically significant. mRNA levels for lipase, trypsinogen, and chymotrypsinogen were raised in ethanol-fed rats. Ethanol feeding also increased mRNA levels for the lysosomal enzyme cathepsin B. Furthermore, there was a close, statistically significant correlation between changes in mRNA levels and tissue activities of pancreatic digestive and lysosomal enzymes after ethanol consumption. These results suggest that ethanol increases the capacity of the pancreatic acinar cell to synthesize digestive and lysosomal enzymes, thereby increasing the susceptibility of the gland to enzyme-related injury.

Alcohol-related pancreatic damage: mechanisms and treatment

Pancreatitis is a potentially fatal inflammation of the pancreas often associated with long-term alcohol consumption. Symptoms may result from blockage of small pancreatic ducts as well as from destruction of pancreatic tissue by digestive enzymes. In addition, by-products of alcohol metabolism within the pancreas may damage cell membranes. Research on the causes of pancreatitis may support more effective disease management and provide hope for a potential cure.