Novel Approach for Pancreas Transcriptomics Reveals the Cellular Landscape in Homeostasis and Acute Pancreatitis.

BACKGROUND & AIMS: Acinar cells produce digestive enzymes that impede transcriptomic characterization of the exocrine pancreas. Thus, single-cell RNA-sequencing studies of the pancreas underrepresent acinar cells relative to histological expectations, and a robust approach to capture pancreatic cell responses in disease states is needed. We sought to innovate a method that overcomes these challenges to accelerate study of the pancreas in health and disease. METHODS: We leverage FixNCut, a single-cell RNA-sequencing approach in which tissue is reversibly fixed with dithiobis(succinimidyl propionate) before dissociation and single-cell preparation. We apply FixNCut to an established mouse model of acute pancreatitis, validate findings using GeoMx whole transcriptome atlas profiling, and integrate our data with prior studies to compare our method in both mouse and human pancreas datasets. RESULTS: FixNCut achieves unprecedented definition of challenging pancreatic cells, including acinar and immune populations in homeostasis and acute pancreatitis, and identifies changes in all major cell types during injury and recovery. We define the acinar transcriptome during homeostasis and acinar-to-ductal metaplasia and establish a unique gene set to measure deviation from normal acinar identity. We characterize pancreatic immune cells, and analysis of T-cell subsets reveals a polarization of the homeostatic pancreas toward type-2 immunity. We report immune responses during acute pancreatitis and recovery, including early neutrophil infiltration, expansion of dendritic cell subsets, and a substantial shift in the transcriptome of macrophages due to both resident macrophage activation and monocyte infiltration. CONCLUSIONS: FixNCut preserves pancreatic transcriptomes to uncover novel cell states during homeostasis and following pancreatitis, establishing a broadly applicable approach and reference atlas for study of pancreas biology and disease.

The pathogenic "symphony" in type 1 diabetes: A disorder of the immune system, ß cells, and exocrine pancreas.

Type 1 diabetes (T1D) is widely considered to result from the autoimmune destruction of insulin-producing ß cells. This concept has been a central tenet for decades of attempts seeking to decipher the disorder's pathogenesis and prevent/reverse the disease. Recently, this and many other disease-related notions have come under increasing question, particularly given knowledge gained from analyses of human T1D pancreas. Perhaps most crucial are findings suggesting that a collective of cellular constituents-immune, endocrine, and exocrine in origin-mechanistically coalesce to facilitate T1D. This review considers these emerging concepts, from basic science to clinical research, and identifies several key remaining knowledge voids.

The role of Ca2+ signalling in the pathology of exocrine pancreas.

Exocrine pancreas has been the field of many successful studies in pancreatic physiology and pathology. However, related disease - acute pancreatitis (AP) is still takes it toll with more than 100,000 related deaths worldwide per year. In spite of significant scientific progress and several human trials currently running for AP, there is still no specific treatment in the clinic. Studies of the mechanism of initiation of AP have identified two crucial conditions: sustained elevations of cytoplasmic calcium concentration (Ca2+ plateau) and significantly reduced intracellular energy (ATP depletion). These hallmarks are interdependent, i.e., Ca2+ plateau increase energy demand for its clearance while energy production is greatly affected by the pathology. Result of long standing Ca2+ plateau is destabilisation of the secretory granules and premature activation of the digestive enzymes leading to necrotic cell death. Main attempts so far to break the vicious circle of cell death have been concentrated on reduction of Ca2+ overload or reduction of ATP depletion. This review will summarise these approaches, including recent developments of potential therapies for AP.

Changes in Pancreatic Senescence Mediate Pancreatic Diseases.

In recent years, there has been a significant increase in age-related diseases due to the improvement in life expectancy worldwide. The pancreas undergoes various morphological and pathological changes with aging, such as pancreatic atrophy, fatty degeneration, fibrosis, inflammatory cell infiltration, and exocrine pancreatic metaplasia. Meanwhile, these may predispose the individuals to aging-related diseases, such as diabetes, dyspepsia, pancreatic ductal adenocarcinoma, and pancreatitis, as the endocrine and exocrine functions of the pancreas are significantly affected by aging. Pancreatic senescence is associated with various underlying factors including genetic damage, DNA methylation, endoplasmic reticulum (ER) stress, mitochondrial dysfunction, and inflammation. This paper reviews the alternations of morphologies and functions in the aging pancreas, especially ß-cells, closely related to insulin secretion. Finally, we summarize the mechanisms of pancreatic senescence to provide potential targets for treating pancreatic aging-related diseases.

Substance Use Affects Type 1 Diabetes Pancreas Pathology: Implications for Future Studies.

Access to human pancreas samples from organ donors has greatly advanced our understanding of type 1 diabetes pathogenesis; however, previous studies have shown that donors have a high rate of substance use, and its impact on pancreatic histopathology in this disease is not well described. One-hundred-thirty-one type 1 diabetes and 111 control organ donor pancreata from persons 12-89 years of age (mean 29.8 ± 15.5 years) within the Network for Pancreatic Organ donors with Diabetes (nPOD) were examined for insulin positivity, insulitis, amyloid staining, acute and chronic pancreatitis, and chronic exocrine changes (acinar atrophy, fibrosis, fatty infiltration, or periductal fibrosis); findings were compared by history of substance use. A secondary analysis compared exocrine pancreatic histopathologic findings in type 1 diabetes versus control organ donors regardless of substance use history. We observed a high but congruent rate of substance use in type 1 diabetes and control organ donors (66.4% and 64% respectively). Among donors with type 1 diabetes (but not controls), islet amyloid (OR 9.96 [1.22, 81.29]) and acute pancreatitis (OR 3.2 [1.06, 9.63]) were more common in alcohol users while chronic exocrine changes (OR 8.86 [1.13, 69.31]) were more common in cocaine users. Substance use impacted the pancreata of donors with type 1 diabetes more than controls. Overall, despite similar rates of substance use, acute pancreatitis (15.3% versus 4.5%, p=0.0061), chronic pancreatitis (29.8% versus 9.9%, p=0.0001), and chronic exocrine changes (73.3% versus 36.9%, p<0.0001) were more common in type 1 diabetes donors than controls. Alcohol and/or cocaine use in type 1 diabetes organ donors increases exocrine pancreas pathology and islet amyloid deposition but does not affect insulitis or insulin positivity. Exocrine pathology in type 1 diabetes donors is common, and further study of the pathophysiology of these changes is needed.

Loss of the ciliary protein Chibby1 in mice leads to exocrine pancreatic degeneration and pancreatitis.

Primary cilia protrude from the apical surface of many cell types and act as a sensory organelle that regulates diverse biological processes ranging from chemo- and mechanosensation to signaling. Ciliary dysfunction is associated with a wide array of genetic disorders, known as ciliopathies. Polycystic lesions are commonly found in the kidney, liver, and pancreas of ciliopathy patients and mouse models. However, the pathogenesis of the pancreatic phenotype remains poorly understood. Chibby1 (Cby1), a small conserved coiled-coil protein, localizes to the ciliary base and plays a crucial role in ciliogenesis. Here, we report that Cby1-knockout (KO) mice develop severe exocrine pancreatic atrophy with dilated ducts during early postnatal development. A significant reduction in the number and length of cilia was observed in Cby1-KO pancreta. In the adult Cby1-KO pancreas, inflammatory cell infiltration and fibrosis were noticeable. Intriguingly, Cby1-KO acinar cells showed an accumulation of zymogen granules (ZGs) with altered polarity. Moreover, isolated acini from Cby1-KO pancreas exhibited defective ZG secretion in vitro. Collectively, our results suggest that, upon loss of Cby1, concomitant with ciliary defects, acinar cells accumulate ZGs due to defective exocytosis, leading to cell death and progressive exocrine pancreatic degeneration after birth.

Dysregulation of mannose-6-phosphate-dependent cholesterol homeostasis in acinar cells mediates pancreatitis.

Disordered lysosomal/autophagy pathways initiate and drive pancreatitis, but the underlying mechanisms and links to disease pathology are poorly understood. Here, we show that the mannose-6-phosphate (M6P) pathway of hydrolase delivery to lysosomes critically regulates pancreatic acinar cell cholesterol metabolism. Ablation of the Gnptab gene encoding a key enzyme in the M6P pathway disrupted acinar cell cholesterol turnover, causing accumulation of nonesterified cholesterol in lysosomes/autolysosomes, its depletion in the plasma membrane, and upregulation of cholesterol synthesis and uptake. We found similar dysregulation of acinar cell cholesterol, and a decrease in GNPTAB levels, in both WT experimental pancreatitis and human disease. The mechanisms mediating pancreatic cholesterol dyshomeostasis in Gnptab-/- and experimental models involve a disordered endolysosomal system, resulting in impaired cholesterol transport through lysosomes and blockage of autophagic flux. By contrast, in Gnptab-/- liver the endolysosomal system and cholesterol homeostasis were largely unaffected. Gnptab-/- mice developed spontaneous pancreatitis. Normalization of cholesterol metabolism by pharmacologic means alleviated responses of experimental pancreatitis, particularly trypsinogen activation, the disease hallmark. The results reveal the essential role of the M6P pathway in maintaining exocrine pancreas homeostasis and function, and implicate cholesterol disordering in the pathogenesis of pancreatitis.

Endoscopic Pancreatic Drainage Improves Exocrine Pancreatic Function in Patients With Unresectable Pancreatic Cancer: A Double-Blind, Prospective, Randomized, Single-Center, Interventional Study.

OBJECTIVES: Exocrine pancreatic insufficiency is a frequent and clinically relevant complication of pancreatic cancer probably secondary to pancreatic duct obstruction. We aimed at evaluating the impact of endoscopic pancreatic drainage on pancreatic function in patients with unresectable pancreatic cancer. METHODS: A double-blind, prospective, randomized, single-center, interventional study was designed. Patients undergoing endoscopic retrograde cholangiopancreatography for jaundice secondary to unresectable pancreatic cancer were randomized to biliary drainage (group A) or biliopancreatic drainage (group B). Pancreatic function was evaluated by 13C-mixed triglyceride breath test before and 2 weeks after endoscopic retrograde cholangiopancreatography. Breath test result is expressed as 13C-cumulative recovery rate. Abdominal symptoms and nutritional markers were evaluated as secondary outcomes. RESULTS: Twenty patients were included. Sixteen patients had exocrine pancreatic insufficiency, and 13 completed the study (7 in group A and 6 in group B). The median absolute improvement of 13C-cumulative recovery rate was of 23.75% (interquartile range, 9.62-31.74) after biliopancreatic drainage compared with -1.92% (interquartile range, -4.17 to 13.92) after biliary drainage (P = 0.015). Nutritional markers improved after biliopancreatic drainage, but not after biliary drainage. CONCLUSIONS: Biliopancreatic and not biliary endoscopic drainage is associated with a significant improvement of exocrine pancreatic function in patients with unresectable pancreatic cancer.

Newcastle Disease Virus Induced Pathologies Severely Affect the Exocrine and Endocrine Functions of the Pancreas in Chickens.

Newcastle disease virus (NDV) causes a highly contagious and devastating disease in poultry. ND causes heavy economic losses to the global poultry industry by decreasing the growth rate, decrease in egg production high morbidity and mortality. Although significant advances have been made in the vaccine development, outbreaks are reported in vaccinated birds. In this study, we report the damage caused by NDV infection in the pancreatic tissues of vaccinated and specific-pathogen-free chickens. The histopathological examination of the pancreas showed severe damage in the form of partial depletion of zymogen granules, acinar cell vacuolization, necrosis, apoptosis, congestion in the large and small vessels, sloughing of epithelial cells of the pancreatic duct, and mild perivascular edema. Increased plasma levels of corticosterone and somatostatin were observed in NDV-infected chicken at three- and five- days post infection (DPI). A slight decrease in the plasma concentrations of insulin was noticed at 5 DPI. Significant changes were not observed in the plasma levels of glucagon. Furthermore, NDV infection decreased the activity and mRNA expression of amylase, lipase, and trypsin from the pancreas. Taken together, our findings highlight that NDV induces extensive tissue damage in the pancreas, decreases the activity and expression of pancreatic enzymes, and increases plasma corticosterone and somatostatin. These findings provide new insights that a defective pancreas may be one of the reasons for decreased growth performance after NDV infection in chickens.

Sex Differences in the Exocrine Pancreas and Associated Diseases.

Differences in pancreatic anatomy, size, and function exist in men and women. The anatomical differences could contribute to the increase in complications associated with pancreatic surgery in women. Although diagnostic criteria for pancreatitis are the same in men and women, major sex differences in etiology are reported. Alcohol and tobacco predominate in men, whereas idiopathic and obstructive etiologies predominate in women. Circulating levels of estrogens, progesterone, and androgens contribute significantly to overall health outcomes; premenopausal women have lower prevalence of cardiovascular and pancreatic diseases suggesting protective effects of estrogens, whereas androgens promote growth of normal and cancerous cells. Sex chromosomes and gonadal and nongonadal hormones together determine an individual's sex, which is distinct from gender or gender identity. Human pancreatic disease etiology, outcomes, and sex-specific mechanisms are largely unknown. In rodents of both sexes, glucocorticoids and estrogens from the adrenal glands influence pancreatic secretion and acinar cell zymogen granule numbers. Lack of corticotropin-releasing factor receptor 2 function, a G protein-coupled receptor whose expression is regulated by both estrogens and glucocorticoids, causes sex-specific changes in pancreatic histopathology, zymogen granule numbers, and endoplasmic reticulum ultrastructure changes in acute pancreatitis model. Here, we review existing literature on sex differences in the normal exocrine pancreas and mechanisms that operate at homeostasis and diseased states in both sexes. Finally, we review pregnancy-related pancreatic diseases and discuss the effects of sex differences on proposed treatments in pancreatic disease.

MFG-E8 Plays an Important Role in Attenuating Cerulein-Induced Acute Pancreatitis in Mice.

Milk fat globule-EGF factor 8 (MFG-E8) is a secreted glycoprotein that regulates tissue homeostasis, possesses potent anti-inflammatory properties, and protects against tissue injury. The human pancreas expresses MFG-E8; however, the role of MFG-E8 in the pancreas remains unclear. We examined the expression of MFG-E8 in the pancreas at baseline and during cerulein-induced acute pancreatitis in mice and determined whether MFG-E8 attenuates the progression of pancreatitis, a serious inflammatory condition that can be life-threatening. We administered cerulein to wild-type (WT) and Mfge8 knockout (KO) mice to induce pancreatitis. Immunoblot analysis showed that MFG-E8 is constitutively expressed in the murine pancreas and is increased in mice with cerulein-induced acute pancreatitis. In situ hybridization revealed that ductal epithelial cells in the mouse pancreas express Mfge8 transcripts at baseline. During pancreatitis, Mfge8 transcripts were abundantly expressed in acinar cells and endothelial cells in addition to ductal epithelial cells. Knocking out Mfge8 in mice exacerbated the severity of cerulein-induced acute pancreatitis and delayed its resolution. In contrast, administration of recombinant MFG-E8 attenuated cerulein-induced acute pancreatitis and promoted repair of pancreatic injury in Mfge8 KO mice. Taken together, our study suggests that MFG-E8 protects the pancreas against inflammatory injury and promotes pancreatic tissue repair. MFG-E8 may represent a novel therapeutic target in acute pancreatitis.

Lycopene Inhibits Oxidative Stress-Mediated Inflammatory Responses in Ethanol/Palmitoleic Acid-Stimulated Pancreatic Acinar AR42J Cells.

High alcohol intake results in the accumulation of non-oxidative ethanol metabolites such as fatty acid ethyl esters (FAEEs) in the pancreas. High FAEE concentrations mediate pancreatic acinar cell injury and are associated with alcoholic pancreatitis. Treatment with ethanol and the fatty acid palmitoleic acid (EtOH/POA) increased the levels of palmitoleic acid ethyl ester and induced zymogen activation and cytokine expression in pancreatic acinar cells. EtOH/POA induces nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-mediated reactive oxygen species (ROS) production and pancreatic acinar cell injury. Lycopene, a bright-red carotenoid, is a potent antioxidant due to its high number of conjugated double bands. This study aimed to investigate whether lycopene inhibits the EtOH/POA-induced increase in ROS production, zymogen activation, and expression of the inflammatory cytokine IL-6 in EtOH/POA-stimulated pancreatic acinar AR42J cells. EtOH/POA increased the ROS levels, NADPH oxidase and NF-κB activities, zymogen activation, IL-6 expression, and mitochondrial dysfunction, which were inhibited by lycopene. The antioxidant N-acetylcysteine and NADPH oxidase 1 inhibitor ML171 suppressed the EtOH/POA-induced increases in ROS production, NF-κB activation, zymogen activation, and IL-6 expression. Therefore, lycopene inhibits EtOH/POA-induced mitochondrial dysfunction, zymogen activation, and IL-6 expression by suppressing NADPH oxidase-mediated ROS production in pancreatic acinar cells.

MiR-204-5p Performs a Protective Effect on Cerulein-Induced Rat Pancreatic Acinar Cell AR42J Cell Damage by Targeting Tyrosine 3-Monooxygenase/Tryptophan 5-Monooxygenase Activation Protein Gamma and Regulating PI3K/Hippo Pathways.

OBJECTIVE: This research plans to address the function of miR-204-5p/tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein gamma (YWHAG) in cerulein-induced acute pancreatitis (AP). METHODS: Rat pancreatic acinar cell AR42J was stimulated by 100 nmol/L of cerulein to mimic the situation in AP. Gene Expression Omnibus database was used to select differentially expressed genes. StarBase database and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were used to select the target genes of miR-204-5p, which were further affirmed by dual luciferase assay. The biological behaviors of AR42J cells were measured by cell proliferation and flow cytometry assays. Quantitative real-time polymerase chain reaction and western blot assays were executed to assess YWHAG expression. The secretion of C-C Motif Chemokine Ligand 2/Timp metallopeptidase inhibitor 1 in AR42J cells was evaluated by enzyme-linked immunosorbent assay. The protein expression of YAP1/p-YAP1/PI3K/p-PI3K was measured by western blot. RESULTS: miR-204-5p expression was profoundly reduced in cerulein-induced AP model. YWHAG was upregulated in cerulein-induced AP model and related to C-C Motif Chemokine Ligand 2/Timp1. In addition to the negative association between miR-204-5p and YWHAG, the alleviation impact of miR-204-5p mimic on cerulein-induced AR42J cell damage was blocked by YWHAG overexpression and PI3K/Hippo signaling pathways activation. CONCLUSIONS: These observations indicated that the alleviation impact of miR-204-5p on cerulein-induced AR42J cell damage was mediated via YWHAG and PI3K/Hippo signaling pathways.

DIAGNOSIS OF ENDOCRINE DISEASE: Diagnosing and classifying diabetes in diseases of the exocrine pancreas.

Diabetes in the setting of diseases of the exocrine pancreas has long existed as a known, but underdiagnosed or misdiagnosed, disorder. It currently finds itself in a state of taxonomic dereliction and requires a long overdue refurbishment. Correct conceptualisation is a key precondition for knowledge development in this disorder. This article lays out the epistemological foundation for diabetes of the exocrine pancreas (DEP) and presents a synthesis of the current interdisciplinary discourse on diagnosing and classifying DEP. A diagnosis of DEP in people with no medical records of pre-existing diabetes is generally based on the most up-to-date biochemical criteria endorsed by the American Diabetes Association and European Association for the Study of Diabetes. The presence of exocrine pancreatic dysfunction is not considered a mandatory diagnostic criterion for DEP but is rather a significant risk factor for developing DEP. DEP principally comprises post-pancreatitis diabetes mellitus, pancreatic cancer-related diabetes, and cystic fibrosis-related diabetes, which are mutually exclusive with autoimmune diabetes and type 2 diabetes. Other exclusions and stipulations apply. The DEP criteria will be instrumental in aiding optimal design and conduct of clinical studies, uniform collection of health utilisation data, meaningful comparison of scientific findings across countries, and clear communication among stakeholders (healthcare providers, patients, medical regulatory authorities, pharmaceutical industry).

Islet cell dedifferentiation is a pathologic mechanism of long-standing progression of type 2 diabetes.

Dedifferentiation has been implicated in ß cell dysfunction and loss in rodent diabetes. However, the pathophysiological significance in humans remains unclear. To elucidate this, we analyzed surgically resected pancreatic tissues of 26 Japanese subjects with diabetes and 11 nondiabetic subjects, who had been overweight during adulthood but had no family history of diabetes. The diabetic subjects were subclassified into 3 disease stage categories, early, advanced, and intermediate. Despite no numerical changes in endocrine cells immunoreactive for chromogranin A (ChgA), diabetic islets showed profound ß cell loss, with an increase in α cells without an increase in insulin and glucagon double-positive cells. The proportion of dedifferentiated cells that retain ChgA immunoreactivity without 4 major islet hormones was strikingly increased in diabetic islets and rose substantially during disease progression. The increased dedifferentiated cell ratio was inversely correlated with declining C-peptide index. Moreover, a subset of islet cells converted into exocrine-like cells during disease progression. These results indicate that islet remodeling with dedifferentiation is the underlying cause of ß cell failure during the course of diabetes progression in humans.

Galactose protects pancreatic acinar cells from cerulein induced damage by regulating FGF21 and Klotho.

To investigate the effect and mechanism of galactose on cerulean-induced pancreatic acinar cell injury. Acute pancreatitis cell injury model was established by arbusin-induced pancreatic acinar cell AR42J injury; galactose (25, 50, 100 mmol / L) was used to treat the injured cells, and the optimal concentration was 50 mmol / L; cell counting kit (CCK-8), enzyme linked immunosorbent assay (ELISA) to detect cell survival rate and necrosis rate; flow cytometry and Western blotting (Western blot) to detect cell apoptosis and autologous phage-related gene (Beclin1) and microtubule-associated protein 1 light chain 3 (LC3), apoptosis-related protein B-cell lymphoma / leukemia-2 (Bcl-2), Bcl-2-related X gene (Bax), and fibroblasts Expression of growth factor 21 antibody (FGF21) and anti-aging gene Klotho. A pancreatic acinar cell injury model was successfully established with cerana (100 nmol / L); galactose (25, 50, 100 mmol/L) In a concentration-dependent manner, the inhibitory effect of ceriferin on AR42J injury was inhibited at an optimal concentration of 50 mmol / L. Compared with the ceriferin group, the apoptosis rate of AR42J cells in the galactose group was significantly reduced. table Significantly increased, Bcl-2, FGF21 and Klotho protein expression was significantly increased, Bax protein was significantly decreased; the FGF21 inhibitor can be significantly reduced on galactose these caerulein-induced AR42J cells. Galactose can inhibit the apoptosis and autophagy of pancreatic acinar cells induced by cerana, and its potential mechanism is to up-regulate FGF21 and Klotho, providing a new potential drug for the treatment of acute pancreatitis.

Transcriptional profiles of human islet and exocrine endothelial cells in subjects with or without impaired glucose metabolism.

In experimental studies, pancreatic islet microvasculature is essential for islet endocrine function and mass, and islet vascular morphology is altered in diabetic subjects. Even so, almost no information is available concerning human islet microvascular endothelial cell (MVEC) physiology and gene expression. In this study, islets and exocrine pancreatic tissue were acquired from organ donors with normoglycemia or impaired glucose metabolism (IGM) immediately after islet isolation. Following single-cell dissociation, primary islet- and exocrine MVECs were obtained through fluorescence-activated cell sorting (FACS) and transcriptional profiles were generated using AmpliSeq. Multiple gene sets involved in general vascular development and extracellular matrix remodeling were enriched in islet MVEC. In exocrine MVEC samples, multiple enriched gene sets that relate to biosynthesis and biomolecule catabolism were found. No statistically significant enrichment was found in gene sets related to autophagy or endoplasmic reticulum (ER) stress. Although ample differences were found between islet- and exocrine tissue endothelial cells, no differences could be observed between normoglycemic donors and donors with IGM at gene or gene set level. Our data is consistent with active angiogenesis and vascular remodeling in human islets and support the notion of ongoing endocrine pancreas tissue repair and regeneration even in the adult human.

Malignant epithelial/exocrine tumors of the pancreas.

Pancreatic malignant exocrine tumors represent the most important cause of cancer-related death for pancreatic neoplasms. The most common tumor type in this category is represented by pancreatic ductal adenocarcinoma (PDAC), an ill defined, stroma-rich, scirrhous neoplasm with glandular differentiation. Here we present the relevant characteristics of the most important PDAC variants, namely adenosquamous carcinoma, colloid carcinoma, undifferentiated carcinoma, undifferentiated carcinoma with osteoclast-like giant cells, signet ring carcinoma, medullary carcinoma and hepatoid carcinoma. The other categories of malignant exocrine tumors, characterized by fleshy, stroma-poor, circumscribed neoplasms, include acinar cell carcinoma (pure and mixed), pancreatoblastoma, and solid pseudopapillary neoplasms. The most important macroscopic, histologic, immunohistochemical and molecular hallmarks of all these tumors, highlighting their key diagnostic/pathological features are presented. Lastly, standardized indications regarding gross sampling and how to compile a formal pathology report for pancreatic malignant exocrine tumors will be provided.

Docosahexaenoic acid inhibits ethanol/palmitoleic acid-induced necroptosis in AR42J cells.

Fatty acid ethyl esters (FAEEs), non-oxidative metabolites of ethanol, are the main causative agents of severe acute pancreatitis resulting from alcohol abuse. Pancreatic acinar cells exposed to ethanol in combination with the fatty acid palmitoleic acid (EtOH/POA) display increased levels of palmitoleic acid ethyl ester and cell death. Oxidative stress and acinar cell necroptosis are implicated in the pathology of severe acute pancreatitis. Docosahexaenoic acid (DHA) serves as a powerful anti-oxidant that reduces pancreatic inflammation and improves the outcomes of patients with acute pancreatitis. We investigated whether treatment of EtOH/POA, as an in vitro model of alcoholic pancreatitis, increases reactive oxygen species (ROS), necroptosis-regulating proteins, and cell death by increasing nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and intracellular calcium. Also, we investigated whether DHA inhibits EtOH/POA-induced alterations in pancreatic acinar AR42J cells. As a result, EtOH/POA increased intracellular and mitochondrial ROS levels, NADPH oxidase activity, necroptosis-regulating proteins, and cell death, which was inhibited by NADPH oxidase inhibitor apocynin, the Ca2+ chelator BAPTA, and DHA. However, DHA did not reduce EtOH/POA-induced increases in Ca2+ oscillation or levels in AR42J cells. Furthermore, EtOH/POA induced mitochondrial dysfunction by reducing mitochondrial membrane polarization and hence, adenosine triphosphate (ATP) production. DHA treatment attenuated EtOH/POA-induced mitochondrial dysfunction. In conclusion, DHA inhibits EtOH/POA-induced necroptosis by suppressing NADPH oxidase activity, reducing ROS levels, preventing mitochondrial dysfunction, and inhibiting activation of necroptosis-regulating proteins in AR42J cells.

Northstar enables automatic classification of known and novel cell types from tumor samples.

Single cell transcriptomics is revolutionising our understanding of tissue and disease heterogeneity, yet cell type identification remains a partially manual task. Published algorithms for automatic cell annotation are limited to known cell types and fail to capture novel populations, especially cancer cells. We developed northstar, a computational approach to classify thousands of cells based on published data within seconds while simultaneously identifying and highlighting new cell states such as malignancies. We tested northstar on data from glioblastoma, melanoma, and seven different healthy tissues and obtained high accuracy and robustness. We collected eleven pancreatic tumors and identified three shared and five private neoplastic cell populations, offering insight into the origins of neuroendocrine and exocrine tumors. Northstar is a useful tool to assign known and novel cell type and states in the age of cell atlases.