Screening Metabolic Biomarkers in KRAS Mutated Mouse Acinar and Human Pancreatic Cancer Cells via Single-Cell Mass Spectrometry.

Pancreatic cancer is a highly aggressive and rapidly progressing disease, often diagnosed in advanced stages due to the absence of early noticeable symptoms. The KRAS mutation is a hallmark of pancreatic cancer, yet the underlying mechanisms driving pancreatic carcinogenesis remain elusive. Cancer cells display significant metabolic heterogeneity, which is relevant to the pathogenesis of cancer. Population measurements may obscure information about the metabolic heterogeneity among cancer cells. Therefore, it is crucial to analyze metabolites at the single-cell level to gain a more comprehensive understanding of metabolic heterogeneity. In this study, we employed a 3D-printed ionization source for metabolite analysis in both mice and human pancreatic cancer cells at the single-cell level. Using advanced machine learning algorithms and mass spectral feature selection, we successfully identified 23 distinct metabolites that are statistically significantly different in KRAS mutant human pancreatic cancer cells and mouse acinar cells bearing the oncogenic KRAS mutation. These metabolites encompass a variety of chemical classes, including organic nitrogen compounds, organic acids and derivatives, organoheterocyclic compounds, benzenoids, and lipids. These findings shed light on the metabolic remodeling associated with KRAS-driven pancreatic cancer initiation and indicate that the identified metabolites hold promise as potential diagnostic markers for early detection in pancreatic cancer patients.

Elimination of intracellular Ca2+ overload by BAPTA­AM liposome nanoparticles: A promising treatment for acute pancreatitis.

Calcium overload, a notable instigator of acute pancreatitis (AP), induces oxidative stress and an inflammatory cascade, subsequently activating both endogenous and exogenous apoptotic pathways. However, there is currently lack of available pharmaceutical interventions to alleviate AP by addressing calcium overload. In the present study, the potential clinical application of liposome nanoparticles (LNs) loaded with 1,2­bis(2­aminophenoxy)ethane­N,N,N',N'­tetraacetic acid tetrakis (acetoxymethyl ester) (BAPTA­AM), a cell­permeant calcium chelator, was investigated as a therapeutic approach for the management of AP. To establish the experimental models in vitro, AR42J cells were exposed to high glucose/sodium oleate (HGO) to induce necrosis, and in vivo, intra­ductal taurocholate (TC) infusion was used to induce AP. The findings of the present study indicated that the use of BAPTA­AM­loaded LN (BLN) effectively and rapidly eliminated excessive Ca2+ and reactive oxygen species, suppressed mononuclear macrophage activation and the release of inflammatory cytokines, and mitigated pancreatic acinar cell apoptosis and necrosis induced by HGO. Furthermore, the systemic administration of BLN demonstrated promising therapeutic potential in the rat model of AP. Notably, BLN significantly enhanced the survival rates of rats subjected to the TC challenge, increasing from 37.5 to 75%. This improvement was attributed to the restoration of pancreatic function, as indicated by improved blood biochemistry indices and alleviation of pancreatic lesions. The potential therapeutic efficacy of BLN in rescuing patients with AP is likely attributed to its capacity to inhibit oxidative stress, prevent premature activation of zymogens and downregulate the expression of TNF­α, IL­6 and cathepsin B. Thus, BLN demonstrated promising value as a novel therapeutic approach for promptly alleviating the burden of intracellular Ca2+ overload in patients with AP.

Oral bacteria accelerate pancreatic cancer development in mice.

OBJECTIVE: Epidemiological studies highlight an association between pancreatic ductal adenocarcinoma (PDAC) and oral carriage of the anaerobic bacterium Porphyromonas gingivalis, a species highly linked to periodontal disease. We analysed the potential for P. gingivalis to promote pancreatic cancer development in an animal model and probed underlying mechanisms. DESIGN: We tracked P. gingivalis bacterial translocation from the oral cavity to the pancreas following administration to mice. To dissect the role of P. gingivalis in PDAC development, we administered bacteria to a genetically engineered mouse PDAC model consisting of inducible acinar cell expression of mutant Kras (Kras +/LSL-G12D; Ptf1a-CreER, iKC mice). These mice were used to study the cooperative effects of Kras mutation and P. gingivalis on the progression of pancreatic intraepithelial neoplasia (PanIN) to PDAC. The direct effects of P. gingivalis on acinar cells and PDAC cell lines were studied in vitro. RESULTS: P. gingivalis migrated from the oral cavity to the pancreas in mice and can be detected in human PanIN lesions. Repetitive P. gingivalis administration to wild-type mice induced pancreatic acinar-to-ductal metaplasia (ADM), and altered the composition of the intrapancreatic microbiome. In iKC mice, P. gingivalis accelerated PanIN to PDAC progression. In vitro, P. gingivalis infection induced acinar cell ADM markers SOX9 and CK19, and intracellular bacteria protected PDAC cells from reactive oxygen species-mediated cell death resulting from nutrient stress. CONCLUSION: Taken together, our findings demonstrate a causal role for P. gingivalis in pancreatic cancer development in mice.

Cancer-Associated Fibroblast Induces Acinar-to-Ductal Cell Transdifferentiation and Pancreatic Cancer Initiation Via LAMA5/ITGA4 Axis.

BACKGROUND & AIMS: Pancreatic ductal adenocarcinoma (PDAC) is characterized by desmoplastic stroma surrounding most tumors. Activated stromal fibroblasts, namely cancer-associated fibroblasts (CAFs), play a major role in PDAC progression. We analyzed whether CAFs influence acinar cells and impact PDAC initiation, that is, acinar-to-ductal metaplasia (ADM). ADM connection with PDAC pathophysiology is indicated, but not yet established. We hypothesized that CAF secretome might play a significant role in ADM in PDAC initiation. METHODS: Mouse and human acinar cell organoids, acinar cells cocultured with CAFs and exposed to CAF-conditioned media, acinar cell explants, and CAF cocultures were examined by means of quantitative reverse transcription polymerase chain reaction, RNA sequencing, immunoblotting, and confocal microscopy. Data from liquid chromatography with tandem mass spectrometry analysis of CAF-conditioned medium and RNA sequencing data of acinar cells post-conditioned medium exposure were integrated using bioinformatics tools to identify the molecular mechanism for CAF-induced ADM. Using confocal microscopy, immunoblotting, and quantitative reverse transcription polymerase chain reaction analysis, we validated the depletion of a key signaling axis in the cell line, acinar explant coculture, and mouse cancer-associated fibroblasts (mCAFs). RESULTS: A close association of acino-ductal markers (Ulex europaeus agglutinin 1, amylase, cytokeratin-19) and mCAFs (α-smooth muscle actin) in LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx1Cre (KPC) and LSL-KrasG12D/+; Pdx1Cre (KC) autochthonous progression tumor tissue was observed. Caerulein treatment-induced mCAFs increased cytokeratin-19 and decreased amylase in wild-type and KC pancreas. Likewise, acinar-mCAF cocultures revealed the induction of ductal transdifferentiation in cell line, acinar-organoid, and explant coculture formats in WT and KC mice pancreas. Proteomic and transcriptomic data integration revealed a novel laminin α5/integrinα4/stat3 axis responsible for CAF-mediated acinar-to-ductal cell transdifferentiation. CONCLUSIONS: Results collectively suggest the first evidence for CAF-influenced acino-ductal phenotypic switchover, thus highlighting the tumor microenvironment role in pancreatic carcinogenesis inception.

A reversible epigenetic memory of inflammatory injury controls lineage plasticity and tumor initiation in the mouse pancreas.

Inflammation is essential to the disruption of tissue homeostasis and can destabilize the identity of lineage-committed epithelial cells. Here, we employ lineage-traced mouse models, single-cell transcriptomic and chromatin analyses, and CUT&TAG to identify an epigenetic memory of inflammatory injury in the pancreatic acinar cell compartment. Despite resolution of pancreatitis, our data show that acinar cells fail to return to their molecular baseline, with retention of elevated chromatin accessibility and H3K4me1 at metaplasia genes, such that memory represents an incomplete cell fate decision. In vivo, we find this epigenetic memory controls lineage plasticity, with diminished metaplasia in response to a second insult but increased tumorigenesis with an oncogenic Kras mutation. The lowered threshold for oncogenic transformation, in turn, can be restored by blockade of MAPK signaling. Together, we define the chromatin dynamics, molecular encoding, and recall of a prolonged epigenetic memory of inflammatory injury that impacts future responses but remains reversible.

Hyperinsulinemia acts via acinar insulin receptors to initiate pancreatic cancer by increasing digestive enzyme production and inflammation.

The rising pancreatic cancer incidence due to obesity and type 2 diabetes is closely tied to hyperinsulinemia, an independent cancer risk factor. Previous studies demonstrated reducing insulin production suppressed pancreatic intraepithelial neoplasia (PanIN) pre-cancerous lesions in Kras-mutant mice. However, the pathophysiological and molecular mechanisms remained unknown, and in particular it was unclear whether hyperinsulinemia affected PanIN precursor cells directly or indirectly. Here, we demonstrate that insulin receptors (Insr) in KrasG12D-expressing pancreatic acinar cells are dispensable for glucose homeostasis but necessary for hyperinsulinemia-driven PanIN formation in the context of diet-induced hyperinsulinemia and obesity. Mechanistically, this was attributed to amplified digestive enzyme protein translation, triggering of local inflammation, and PanIN metaplasia in vivo. In vitro, insulin dose-dependently increased acinar-to-ductal metaplasia formation in a trypsin- and Insr-dependent manner. Collectively, our data shed light on the mechanisms connecting obesity-driven hyperinsulinemia and pancreatic cancer development.

Recurrent gastric amphicrine tumor with neuroendocrine and pancreatic acinar cell differentiation and somatic MEN1 inactivation arisen during immunotherapy.

Amphicrine neoplasms (ANs) are poorly understood epithelial malignancies composed of cells with co-existing exocrine-neuroendocrine features. Here, we report a recurrent mucin-producing gastric amphicrine tumor co-expressing neuroendocrine (chromogranin-A, synaptophysin, and CD56) and pancreatic acinar cell (BCL10 and trypsin) markers, arisen in a 64-year-old woman during adjuvant immunotherapy for melanoma. Ki-67 was < 2%. The gastric background context was atrophic gastritis. Next-generation sequencing showed MEN1 mutation (p.P71fs*42) coupled with loss of heterozygosity. The key lessons were as follows: (1) gastric ANs can show the co-existence of exocrine mucin-producing elements with neuroendocrine and pancreatic acinar differentiation; (2) they may represent a new entity arising in the context of atrophic gastritis and during immunotherapy; (3) they should be considered in the diagnostic workup of gastric neuroendocrine tumors; and (4) their molecular profile can show striking similarities with well-differentiated neuroendocrine tumors. These findings may be of help to improve the knowledge and the biological taxonomy of ANs.

Tumor Necrosis Factor Alpha Preconditioned Umbilical Cord Mesenchymal Stem Cell-Derived Extracellular Vesicles Enhance the Inhibition of Necroptosis of Acinar cells in Severe Acute Pancreatitis.

Severe acute pancreatitis (SAP) is a common abdominal emergency with a high mortality rate and a lack of effective therapeutic options. Although mesenchymal stem cell (MSC) transplantation is a potential treatment for SAP, the mechanism remains unclear. It has been suggested that MSCs may act mainly through paracrine effects; therefore, we aimed to demonstrate the therapeutic efficacy of extracellular vesicles (EVs) derived from human umbilical cord mesenchymal stem cells (UCMSCs) for SAP. Na-taurocholate was used to induce a rat SAP model through retrograde injection into the common biliopancreatic duct. After 72 h of EVs transplantation, pancreatic pathological damage was alleviated, along with a decrease in serum amylase activity and pro-inflammatory cytokine levels. Interestingly, when UCMSCs were preconditioned with 10 ng/mL tumor necrosis factor alpha (TNF-α) for 48 h, the obtained EVs (named TNF-α-EVs) performed an enhanced efficacy. Furthermore, both animal and cellular experiments showed that TNF-α-EVs alleviated the necroptosis of acinar cells of SAP through RIPK3/MLKL axis. In conclusion, our study demonstrated that TNF-α-EVs were able to enhance the therapeutic effect on SAP by inhibiting necroptosis compared to normal EVs. This study heralds that TNF-α-EVs may be a promising therapeutic approach for SAP in the future.

Calcium/P53/Ninjurin 1 Signaling Mediates Plasma Membrane Rupture of Acinar Cells in Severe Acute Pancreatitis.

Ninjurin 1 (NINJ1) is a double-transmembrane cell-surface protein that might mediate plasma membrane rupture (PMR) and the diffusion of inflammatory factors. PMR is a characteristic of acinar cell injury in severe acute pancreatitis (SAP). However, the involvement of NINJ1 in mediating the PMR of acinar cells in SAP is currently unclear. Our study has shown that NINJ1 is expressed in acinar cells, and the expression is significantly upregulated in sodium-taurocholate-induced SAP. The knockout of NINJ1 delays PMR in acinar cells and alleviates SAP. Moreover, we observed that NINJ1 expression is mediated by Ca2+ concentration in acinar cells. Importantly, we found that Ca2+ overload drives mitochondrial stress to upregulate the P53/NINJ1 pathway, inducing PMR in acinar cells, and amlodipine, a Ca2+ channel inhibitor, can reduce the occurrence of PMR by decreasing the concentration of Ca2+. Our results demonstrate the mechanism by which NINJ1 induces PMR in SAP acinar cells and provide a potential new target for treatment of SAP.

Intrapancreatic fat, pancreatitis, and pancreatic cancer.

Pancreatic cancer is typically detected at an advanced stage, and is refractory to most forms of treatment, contributing to poor survival outcomes. The incidence of pancreatic cancer is gradually increasing, linked to an aging population and increasing rates of obesity and pancreatitis, which are risk factors for this cancer. Sources of risk include adipokine signaling from fat cells throughout the body, elevated levels of intrapancreatic intrapancreatic adipocytes (IPAs), inflammatory signals arising from pancreas-infiltrating immune cells and a fibrotic environment induced by recurring cycles of pancreatic obstruction and acinar cell lysis. Once cancers become established, reorganization of pancreatic tissue typically excludes IPAs from the tumor microenvironment, which instead consists of cancer cells embedded in a specialized microenvironment derived from cancer-associated fibroblasts (CAFs). While cancer cell interactions with CAFs and immune cells have been the topic of much investigation, mechanistic studies of the source and function of IPAs in the pre-cancerous niche are much less developed. Intriguingly, an extensive review of studies addressing the accumulation and activity of IPAs in the pancreas reveals that unexpectedly diverse group of factors cause replacement of acinar tissue with IPAs, particularly in the mouse models that are essential tools for research into pancreatic cancer. Genes implicated in regulation of IPA accumulation include KRAS, MYC, TGF-ß, periostin, HNF1, and regulators of ductal ciliation and ER stress, among others. These findings emphasize the importance of studying pancreas-damaging factors in the pre-cancerous environment, and have significant implications for the interpretation of data from mouse models for pancreatic cancer.

Acinar-to-Ductal Metaplasia (ADM): On the Road to Pancreatic Intraepithelial Neoplasia (PanIN) and Pancreatic Cancer.

Adult pancreatic acinar cells show high plasticity allowing them to change in their differentiation commitment. Pancreatic acinar-to-ductal metaplasia (ADM) is a cellular process in which the differentiated pancreatic acinar cells transform into duct-like cells. This process can occur as a result of cellular injury or inflammation in the pancreas. While ADM is a reversible process allowing pancreatic acinar regeneration, persistent inflammation or injury can lead to the development of pancreatic intraepithelial neoplasia (PanIN), which is a common precancerous lesion that precedes pancreatic ductal adenocarcinoma (PDAC). Several factors can contribute to the development of ADM and PanIN, including environmental factors such as obesity, chronic inflammation and genetic mutations. ADM is driven by extrinsic and intrinsic signaling. Here, we review the current knowledge on the cellular and molecular biology of ADM. Understanding the cellular and molecular mechanisms underlying ADM is critical for the development of new therapeutic strategies for pancreatitis and PDAC. Identifying the intermediate states and key molecules that regulate ADM initiation, maintenance and progression may help the development of novel preventive strategies for PDAC.

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.

Gastric Amphicrine Carcinoma Showing Neuroendocrine and Pancreatic Acinar Cell Differentiation. Lesson from a Challenging Case Opening New Perspectives in the Diagnostic Work-Up of Gastric Neuroendocrine Neoplasms.

Amphicrine carcinomas are epithelial neoplasms composed of cells with co-existing exocrine-neuroendocrine phenotype and are challenging lesions from both diagnostic and therapeutic perspectives.Here, we report the case of a 63-year-old male patient with a gastric nodule that was endoscopically biopsied, revealing histological features of a type 3 well-differentiated gastric neuroendocrine tumor (NET). At imaging, the lesion was single and limited to the stomach, but did not present In-111Octreotide uptake, despite SSTR2A immunohistochemical expression. The patient underwent a wedge resection of the gastric wall, with a final pathological diagnosis of amphicrine carcinoma with pancreatic acinar cell and neuroendocrine features (pT1b). Predictive immunohistochemistry showed microsatellite stability and negative HER2 status. Hotspot targeted deep sequencing of 57 genes showed no somatic mutation, in agreement with the low mutational burden reported for gastric amphicrine carcinomas. Due to a low stage of the tumor and the poor performance status of the patient, no additional oncological treatment was administered. The patient was disease-free after 18 months.This unusual case highlights the importance of considering amphicrine carcinoma in the diagnostic work-up of gastric type 3 NET. This can be done by including in the immunohistochemical panel non-neuroendocrine markers, such as the pancreatic acinar cell and glandular ones. Correct pathological diagnosis is pivotal to determine the appropriate staging (NET vs exocrine one) for surgical and oncological management.

Novel Insights Into Immunohistochemical Analysis For Acinar Cell Neoplasm of The Pancreas: Carboxypeptidase A2, Carboxypeptidase A1, and Glycoprotein 2.

Acinar cell carcinoma (ACC) is a rare and highly malignant pancreatic tumor. Owing to histologic similarity, ACC is often difficult to distinguish from other solid medullary pancreatic tumors, particularly neuroendocrine neoplasm (NEN) and intraductal tubulopapillary neoplasm (ITPN). We aimed to identify new immunohistochemical markers commonly expressed in tumor cells with acinar cell differentiation and useful for both surgical and small biopsy specimens. Candidate molecules exclusively expressed in neoplastic or non-neoplastic acinar cells in pancreatic tissues with specific and available antibodies suitable for immunohistochemistry were selected. We selected carboxypeptidase A1 (CPA1), carboxypeptidase A2 (CPA2), and glycoprotein 2 (GP2), which were expressed in 100%, 100%, and 96% of cases, respectively, in ACC (n=27) or neoplasia with acinar cell differentiation, including mixed acinar-neuroendocrine carcinoma (n=9), mixed acinar-ductal carcinoma (n=3), pancreatoblastoma (n=4), and acinar cystic transformation (n=2), in the cytoplasm of tumor cells with a granular pattern. Both CPA2 and CPA1 were not expressed in any other tumors without acinar cell differentiation, including NEN (n=44), pancreatic ductal adenocarcinoma (n=44), and ITPN (n=4). GP2 was not expressed in these tumors except in rare cases, including 14% of NEN, 15% of intraductal papillary-mucinous neoplasm, 25% of intraductal oncocytic papillary neoplasm, 25% of ITPN, and 7% of pancreatic ductal adenocarcinoma, wherein a small proportion of tumor cells expressed GP2 in their apical cell membrane. NEN cases also showed cytoplasmic GP2 expression. Therefore, CPA2, CPA1, and potentially GP2 may act as ACC markers.

Acinar Cystic Transformation of the Pancreas: Histomorphology and Molecular Analysis to Unravel its Heterogeneous Nature.

Acinar cystic transformation (ACT) of the pancreas, previously called acinar cell cystadenoma, is a poorly understood and rare entity among pancreatic cystic lesions. This study aims to clarify its real nature. This research cohort included 25 patients with pancreatic ACT, representing the largest series in the literature. We describe their clinicopathological features and molecular profile using next-generation sequencing. ACT arose more often in women (F/M≃2:1), in the body-tail region, with a mean size of ~4 cm. At the latest follow-up, all patients were alive and disease free. Histologically, a typical acinar epithelium lined all cysts, intermingled with ductal-like epithelium in 11/25 (44%) cases. All the cases lacked any evidence of malignancy. Three ACT showed peculiar features: 1 showed an extensive and diffuse microcystic pattern, and the other 2 harbored foci of low-grade pancreatic intraepithelial neoplasia (PanIN) in the ductal-like epithelium. Next-generation sequencing revealed the presence of 2 pathogenic/likely pathogenic mutations in 2 different cases, 1 with ductal-like epithelium and 1 with PanIN, and affecting KRAS (c.34G>C, p.G12R) and SMO (c.1685G>A, p.R562Q) genes, respectively. The other case with PanIN was not available for sequencing. Overall, our findings support that ACT is a benign entity, potentially arising from heterogeneous conditions/background, including: (1) acinar microcysts, (2) malformations, (3) obstructive/inflammatory setting, (4) genetic predisposition, (5) possible neoplastic origin. Although all indications are that ACT is benign, the potential occurrence of driver mutations suggests discussing a potential role of long-term surveillance for these patients.

Painful lower limb nodules as first symptom of resectable pancreatic acinar cell cancer: a case report.

BACKGROUND: Pancreatic panniculitis is characterized by subcutaneous fat necrosis and is a rare presentation of an underlying pancreatic disease, appearing in approximately 2-3% of all patients with a pancreatic disease. The nodules usually involve the lower extremities. Pancreatic panniculitis is commonly associated with acute or chronic pancreatitis, and occasionally with pancreatic cancer, especially acinar cell carcinoma. CASE PRESENTATION: A 77-year-old Caucasian woman with no significant medical history was referred to our center with multiple painful, itchy, and warm red/blue cutaneous nodules on the left lower leg. These skin lesions were consistent with the clinical diagnosis of panniculitis. The skin biopsy obtained showed a predominantly lobular panniculitis with fat necrosis of which the aspect was highly suspicious for pancreatic panniculitis. Further analysis revealed high lipase serum of > 3000 U/L (normal range < 60 U/L), and on computed tomography scan a mass located between the stomach and the left pancreas was seen. Endoscopic ultrasonography-guided fine-needle biopsy confirmed the diagnosis of acinar cell carcinoma. After discussing the patient in the pancreatobiliary multidisciplinary team meeting, laparoscopic distal pancreatectomy including splenectomy and en bloc wedge resection of the stomach due to tumor in-growth was performed. The cutaneous nodules on both legs disappeared 1-2 days after surgery. No long-term complications were reported during follow-up. One year after surgery, the patient presented with similar symptoms as preoperatively. Computed tomography scan showed local recurrence and distal metastases, which were subsequently confirmed by biopsy. She started with palliative folinic acid-fluorouracil-irinotecan-oxaliplatin chemotherapy but stopped after two cycles because of disease progression. The patient died 2 months later, 13 months after surgical resection. CONCLUSION: This case illustrates the importance of clinically recognizing cutaneous nodules and pathological recognizing the specific microscopic changes as sign of a (malignant) pancreatic disease.

Between early and established chronic pancreatitis: A proposal of "acinar-ductal hybrid mechanism".

BACKGROUND/OBJECTIVES: The recently proposed "new mechanistic definition of chronic pancreatitis (CP)" categorized early CP as a reversible condition. However, there is no clear explanation regarding the pathological condition of early CP, the reason for the development of the disease in only a small portion of the patients with risk factors, and the mechanism for transition from a reversible pathological condition to an irreversible one. METHODS: Based on the available information, a mechanism that could provide answers to the queries associated with CP was proposed. RESULTS: Acinar-ductal coordination is very important for the physiological secretion of pancreatic juice. Inflammation originating from acinar cells undermines the function of proximal ducts and leads to a vicious cycle of sustained inflammation by increasing the viscosity and decreasing the alkalinity of pancreatic juice. Persistent elevation of ductal pressure due to stagnation of pancreatic juice caused by protein plugs, stones, or fibrous scar of ducts converts the reversible pathological condition of early CP to an irreversible one. Diagnostic criteria for early CP proposed by Japanese researchers have enabled to the recognition of patients showing a progression from early to established CP. However, most patients diagnosed with early CP do not experience progression of the disease, suggesting the inadequate specificity of the criteria. CONCLUSION: The "acinar-ductal hybrid mechanism" may explain the pathological condition and progression of early CP. To diagnose early CP more accurately, it is essential to discover specific biomarkers that can discriminate "early CP" from "acute pancreatitis (AP)/recurrent acute pancreatitis (RAP)" and "established CP." Therapeutic intervention in clinical practices through various new approaches is expected to improve the prognosis of patients with CP.

Endoplasmic reticulum stress promoted acinar cell necroptosis in acute pancreatitis through cathepsinB-mediated AP-1 activation.

Acinar cell death and inflammatory response are two important events which determine the severity of acute pancreatitis (AP). Endoplasmic reticulum (ER) stress and necroptosis are involved in this process, but the relationships between them remain unknown. Here, we analyzed the interaction between ER stress and necroptosis and the underlying mechanisms during AP. Experimental pancreatitis was induced in Balb/C mice by caerulein (Cae) and lipopolysaccharide (LPS) or L-arginine (L-Arg) in vivo, and pancreatic acinar cells were also used to follow cellular mechanisms during cholecystokinin (CCK) stimulation in vitro. AP severity was assessed by serum amylase, lipase levels and histological examination. Changes in ER stress, trypsinogen activation and necroptosis levels were analyzed by western blotting, enzyme-linked immunosorbent assay (ELISA), adenosine triphosphate (ATP) analysis or lactate dehydrogenase (LDH) assay. The protein kinase C (PKC)α -mitogen-activated protein kinase (MAPK) -cJun pathway and cathepsin B (CTSB) activation were evaluated by western blotting. Activating protein 1 (AP-1) binding activity was detected by electrophoretic mobility shift assay (EMSA). We found that ER stress is initiated before necroptosis in CCK-stimulated acinar cells in vitro. Inhibition of ER stress by 4-phenylbutyrate (4-PBA) can significantly alleviate AP severity both in two AP models in vivo. 4-PBA markedly inhibited ER stress and necroptosis of pancreatic acinar cells both in vitro and in vivo. Mechanistically, we found that 4-PBA significantly reduced CTSB maturation and PKCα-JNK-cJun pathway -mediated AP-1 activation during AP. Besides, CTSB inhibitor CA074Me markedly blocked PKCα-JNK-cJun pathway -mediated AP-1 activation and necroptosis in AP. However, pharmacologic inhibition of trypsin activity with benzamidine hydrochloride had no effect on PKCα-JNK-cJun pathway and necroptosis in CCK-stimulated pancreatic acinar cells. Furthermore, SR11302, the inhibitor of AP-1, significantly lowered tumor necrosis factor (TNF) α levels, and its subsequent receptor interacting protein kinases (RIP)3 and phosphorylated mixed lineagekinase domain-like (pMLKL) levels, ATP depletion and LDH release rate in CCK-stimulated pancreatic acinar cells. To sum up, all the results indicated that during AP, ER stress promoted pancreatic acinar cell necroptosis through CTSB maturation, thus induced AP-1 activation and TNFα secretion via PKCα-JNK-cJun pathway, not related with trypsin activity. These findings provided potential therapeutic target and treatment strategies for AP or other cell death-related diseases.

Síndrome de hipersecreción de lipasa y lesiones óseas en el cáncer de células acinares del páncreas / Lipase hypersecretion syndrome and bone lesions in acinar cell cancer of the pancreas. Report of one case

Lipase hypersecretion syndrome (LHS) is a rare paraneoplastic syndrome, associated with acinar cell carcinoma of the pancreas (ACCP) in 10% to 15% of patients. Clinically, LHS manifests itself with the appearance of subcutaneous fibrocystic nodules, associated with trophic changes in the overlying skin, such as ulcers or fistulas that are difficult to manage, mainly affecting the lower extremities. Additionally, lipolysis near the joints and in the intraosseous adipose tissue can cause bilateral arthralgias, especially of the knees and ankles. We report a 57-year-old man, with a history of insulin resistance and allergic rhinitis, who presented in June 2019 with multiple subcutaneous nodules in the lower extremities, predominantly in both ankles, associated with arthralgia in that region. Additionally, a CT scan of the abdomen revealed a significant abdominal mass, measuring approximately 17 cm and in contact with the body and tail of the pancreas, pathologically compatible with an ACCP. Treatment with capecitabine was started with a favorable progression. The patient currently presents a small left lateral retro malleolar fistula, which, given the analyzes, studies and reviewed literature is concluded to be a lesion in the context of LHS.

Alzheimer's disease is associated with disruption in thiamin transport physiology: A potential role for neuroinflammation.

Alzheimer's disease (AD) is a neurodegenerative disease characterized by Amyloid-ß peptide (Aß) containing plaques and cognitive deficits. The pathophysiology of AD also involves neuroinflammation. Vitamin B1 (thiamin) is indispensable for normal cellular energy metabolism. Thiamin homeostasis is altered in AD, and its deficiency is known to aggravate AD pathology. Little, however, is known about possible alterations in level of expression of thiamin transporters-1 and -2 (THTR-1 and -2) in the brain of AD, and whether pro-inflammatory cytokines affect thiamin uptake by brain cells. We addressed these issues using brain tissue samples [prefrontal cortex (PFC) and hippocampus (HIP)] from AD patients and from 5XFAD mouse model of AD, together with cultured human neuroblastoma SH-SY5Y cells as model. Our results revealed a significantly lower expression of both THTR-1 and THTR-2 in the PFC and HIP of AD patients and 5XFAD mouse model of AD compared to appropriate normal controls. Further, we found that exposure of the SH-SY5Y cells to pro-inflammatory cytokines (IL-1ß, IL-6, and TNF-α) led to a significant inhibition in thiamin uptake. Focusing on IL-1ß, we found the inhibition in thiamin uptake to be time-dependent and reversible; it was also associated with a substantial reduction in expression of THTR-1 (but not THTR-2) protein and mRNA as well as a decrease in promoter activity of the SLC19A2 gene (which encodes THTR-1). Finally, using transcriptomic analysis, we found that thiamin availability in SH-SY5Y cells caused changes in the expression of genes relevant to AD pathways. These studies demonstrate, for the first time, that thiamin transport physiology/molecular biology parameters are negatively impacted in AD brain and that pro-inflammatory cytokines inhibit thiamin uptake by neuroblastoma cells. The results also support a possible role for thiamin in the pathophysiology of AD.