Peripancreatic Adipose Tissue Research Articles

Reduced production of isoprostanes by peri-pancreatic adipose tissue from Zucker fa/fa rats as a new mechanism for β-cell compensation in insulin resistance and obesity

During early stages of type 2 diabetes, named prediabetes, pancreatic β-cells compensate for insulin resistance through increased insulin secretion in order to maintain normoglycemia. Obesity leads to the development of ectopic fat deposits, among which peri-pancreatic white adipose tissue (pWAT) can communicate with β-cells through soluble mediators. Thus we investigated whether pWAT produced oxygenated lipids, namely isoprostanes and neuroprostanes and whether they can influence β-cell function in obesity. In the Zucker fa/fa rat model, pWAT and epididymal white adipose tissue (eWAT) displayed different inflammatory profiles. In obese rats, pWAT, but not eWAT, released less amounts of 5-F2t-isoprostanes, 15-F2t-isoprostanes, 4-F4t-neuroprostanes and 10-F4t-neuroprostane compared to lean animals. These differences could be explained by a greater induction of antioxidant defenses enzymes such as SOD-1, SOD-2, and catalase in pWAT of obese animals compared to eWAT. In addition, sPLA2 IIA, involved in the release of isoprostanoids from cellular membranes, was decreased in pWAT of obese animals, but not in eWAT, and may also account for the reduced release of oxidized lipids by this tissue. At a functional level, 15-F2t-isoprostane epimers, but not 5-F2t-isoprostanes, were able to decrease glucose-induced insulin secretion in pancreatic islets from Wistar rats. This effect appeared to be mediated through activation of the thromboxane A2 receptor and reduction of cAMP signaling in pancreatic islets. In conclusion, through the removal of an inhibitory tone exerted by isoprostanes, we have shown, for the first time, a new mechanism allowing β-cells to compensate for insulin resistance in obesity that is linked to a biocommunication between adipose tissue and β-cells.

Peripancreatic Adipose Tissue Remodeling and Inflammation during High Fat Intake of Palm Oils or Lard in Rats.

Excessive fat consumption leads to the development of ectopic adipose tissues, affecting the organs they surround. Peripancreatic adipose tissue is implicated in glucose homeostasis regulation and can be impaired in obesity. High palm oil consumption’s effects on health are still debated. We hypothesised that crude and refined palm oil high-fat feeding may have contrasting effects on peripancreatic adipocyte hypertrophy, inflammation and lipid oxidation compound production in obese rats. In Wistar rats, morphological changes, inflammation and isoprostanoid production following oxidative stress were assessed in peripancreatic adipose tissue after 12 weeks of diets enriched in crude or refined palm oil or lard (56% energy from fat in each case) versus a standard chow diet (11% energy from fat). Epididymal white and periaortic brown adipose tissues were also included in the study. A refined palm oil diet disturbed glucose homeostasis and promoted lipid deposition in periaortic locations, as well as adipocyte hypertrophy, macrophage infiltration and isoprostanoid (5-F2c-isoprostane and 7(RS)-ST-Δ8-11-dihomo-isofuran) production in peripancreatic adipose tissue. Crude palm oil induced a lower impact on adipose deposits than its refined form and lard. Our results show that the antioxidant composition of crude palm oil may have a protective effect on ectopic adipose tissues under the condition of excessive fat intake.

Peripheral nerve sheath malignancy with multiple metastasis: a rare clinical case

Background. Tumours of peripheral nervous system are represented by benign and malignant neoplasms with different clinical and biological traits. Malignant peripheral nerve sheath tumours of paraspinal localisation with the involvement of nerve structures are extremely rare and may occur isolated or comorbid with congenital neurofibromatosis. Current literature contains a few bioptic and selected autopsy clinical reports. Herewith, we present an own sectional observation of a rare malignant peripheral nerve sheath tumour with multiple metastasis supplemented with morphological and immunohistochemical descriptions.Clinical Case Description. An autopsy was performed on a 30-yo man’s cadaver. A tumour infiltrate was observed along Th5—Th9 of the spinal column intimately associated with thoracic vertebral bodies. Metastases were detected in the right lung, myocardium, peripancreatic and perirenal adipose tissue. Histological tumour examination revealed heterogeneous solid and rosette-like structures. Tumour immunophenotype: vimentin+, pancytokeratin-, CD45-, S-100+, NSE+, GFAP-, proliferative activity index (Ki-67 = 75-80%). This profile is descriptive of peripheral nerve sheath malignancy of high grade with multiple organic metastases.Conclusion. The sectional observation presented illustrates the difficulty to in vivo diagnose rare peripheral nerve sheath malignancies due to their infiltrative growth into spinal bone marrow and metastasis to organs (lungs, myocardium, peripancreatic and perirenal adipose tissue).

Pancreatoduodenectomy for Ampullary Cancer after Roux-en-Y Gastric Bypass – An Extremely Rare Case Report

Introduction: Obesity is a known risk factor for periampullary carcinoma. However we have identified in the international literature only 1 case of a patient with ampullary carcinoma and history of gastric bypass submitted to curative surgery. And it is considered a surgery challenge. We present here the second case. Methods: This clinical case describes a female patient, 70 years old, clinically classified as a periampullary neoplasia with resectability criteria and without metastization evidence (cT2N0M0). This patient has a surgical history of a laparoscopic Roux-en-Y gastric bypass in 2017. This clinical case was discussed in the multidisciplinary hepatobilopancreatic meeting, resulting in a curative surgery as proposal. Results: The patient was subjected to a pancreatoduodenectomy (with a terminolateral pancreatojejunal anastomosis and a terminolateral hepaticojejunal anastomosis) with remnant gastrectomy in December of 2020. Postoperative care had no complications, resulting in a clinical discharge thirteen days later. The histological result of the surgical piece showed an ampullary adenocarcinoma moderately differentiated with invasion of peripancreatic adipose tissue, with surgical margins free of neoplasia and 29 nodes were removed (6 with metastasis) (pT4, pN1). Conclusion: There are multiple types of possible reconstruction for patients after a Roux-en-Y gastric bypass. The rarity of clinical cases is the main factor for the poor evidence to the best clinical practice and for the big surgical challenge that it presents.

Metabolic Syndrome and Abnormal Peri-Organ or Intra-Organ Fat (APIFat) Deposition in Chronic Obstructive Pulmonary Disease: An Overview.

Chronic obstructive pulmonary disease (COPD) is a common disorder with an increasing prevalence, characterised by persistent respiratory symptoms and airflow limitation. Systemic inflammation is involved in the pathogenesis of COPD and can also predispose to metabolic disorders (e.g., metabolic syndrome (MetS) and non-alcoholic fatty liver disease (NAFLD)). Such comorbidities can negatively affect COPD outcomes, cardiovascular risk, and quality of life. Apart from NAFLD, abnormal peri-organ or intra-organ fat (APIFat) could be considered as markers for cardiometabolic diseases and even for COPD. The present narrative review considers the associations of COPD with MetS, NAFLD, and other APIFat, including epicardial, perirenal, peripancreatic, and intramuscular adipose tissue. Further research is needed to define these relationships and identify any potential clinical implications.

Role of adipokines in the assessment of severity and predicting the clinical course of acute pancreatitis.

Acute pancreatitis (AP) is one of the most common diseases requiring hospitalization with increasing incidence. This pathology has variable severity and is associated with significant morbidity and mortality. Early diagnosis, including prognosis of clinical course of the disease is key in the initial clinical management. However, currently available prognostic markers have variable efficacy and the limited utility. Adipokines that are released from the peripancreatic adipose tissue during AP may represent the easy to use and practical AP prognostic markers. This review discusses the current state of knowledge concerning the clinical value of the adipokines in AP, such as adiponectin, ghrelin, interleukin 6, interleukin 8, interleukin 18, leptin, neutrophil gelatinase associated lipocalin, obestatin, resistin, visfatin. Among described adipokines, interleukin 6, neutrophil gelatinase associated lipocalin and resistin seem to be the most valuable as the diagnostic and prognostic markers in AP.

Peripancreatic adipose tissue protects against high-fat-diet-induced hepatic steatosis and insulin resistance in mice

Background/objectivesVisceral adiposity is associated with increased diabetes risk, while expansion of subcutaneous adipose tissue may be protective. However, the visceral compartment contains different fat depots. Peripancreatic adipose tissue (PAT) is an understudied visceral fat depot. Here, we aimed to define PAT functionality in lean and high-fat-diet (HFD)-induced obese mice.Subjects/methodsFour adipose tissue depots (inguinal, mesenteric, gonadal, and peripancreatic adipose tissue) from chow- and HFD-fed male mice were compared with respect to adipocyte size (n = 4–5/group), cellular composition (FACS analysis, n = 5–6/group), lipogenesis and lipolysis (n = 3/group), and gene expression (n = 6–10/group). Radioactive tracers were used to compare lipid and glucose metabolism between these four fat depots in vivo (n = 5–11/group). To determine the role of PAT in obesity-associated metabolic disturbances, PAT was surgically removed prior to challenging the mice with HFD. PAT-ectomized mice were compared to sham controls with respect to glucose tolerance, basal and glucose-stimulated insulin levels, hepatic and pancreatic steatosis, and gene expression (n = 8–10/group).ResultsWe found that PAT is a tiny fat depot (~0.2% of the total fat mass) containing relatively small adipocytes and many “non-adipocytes” such as leukocytes and fibroblasts. PAT was distinguished from the other fat depots by increased glucose uptake and increased fatty acid oxidation in both lean and obese mice. Moreover, PAT was the only fat depot where the tissue weight correlated positively with liver weight in obese mice (R = 0.65; p = 0.009). Surgical removal of PAT followed by 16-week HFD feeding was associated with aggravated hepatic steatosis (p = 0.008) and higher basal (p < 0.05) and glucose-stimulated insulin levels (p < 0.01). PAT removal also led to enlarged pancreatic islets and increased pancreatic expression of markers of glucose-stimulated insulin secretion and islet development (p < 0.05).ConclusionsPAT is a small metabolically highly active fat depot that plays a previously unrecognized role in the pathogenesis of hepatic steatosis and insulin resistance in advanced obesity.

Sexual dimorphism in insulin resistance in a metabolic syndrome rat model

ObjectiveWe assessed the sex-specific differences in the molecular mechanisms of insulin resistance in muscle and adipose tissue, in a MS rat model induced by a high sucrose diet.MethodsMale, female, and ovariectomized female Wistar rats were randomly distributed in control and high-sucrose diet (HSD) groups, supplemented for 24 weeks with 20% sucrose in the drinking water. At the end, we assessed parameters related to MS, analyzing the effects of the HSD on critical nodes of the insulin signaling pathway in muscle and adipose tissue.ResultsAt the end of the treatment, HSD groups of both sexes developed obesity, with a 15, 33 and 23% of body weight gain in male, female, and OVX groups respectively, compared with controls; mainly related to hypertrophy of peripancreatic and gonadal adipose tissue. They also developed hypertriglyceridemia, and liver steatosis, with the last being worse in the HSD females. Compared to the control groups, HSD rats had higher IL1B and TNFA levels and insulin resistance. HSD females were more intolerant to glucose than HSD males. Our observations suggest that insulin resistance mechanisms include an increase in phosphorylated AKT(S473) form in HSD male and female groups and a decrease in phosphorylated P70S6K1(T389) in the HSD male groups from peripancreatic adipose tissue. While in gonadal adipose tissue the phosphorylated form of AKT decreased in HSD females, but not in HSD males. Finally, HSD groups showed a reduction in p-AKT levels in gastrocnemius muscle.ConclusionA high-sucrose diet induces MS and insulin resistance with sex-associated differences and in a tissue-specific manner.

Cancer-associated adipocytes promote pancreatic cancer progression through SAA1 expression.

Although pancreatic cancer often invades peripancreatic adipose tissue, little information is known about cancer‐adipocyte interaction. We first investigated the ability of adipocytes to de‐differentiate to cancer‐associated adipocytes (CAAs) by co‐culturing with pancreatic cancer cells. We then examined the effects of CAA‐conditioned medium (CAA‐CM) on the malignant characteristics of cancer cells, the mechanism underlying those effects, and their clinical relevance in pancreatic cancer. When 3T3‐L1 adipocytes were co‐cultured with pancreatic cancer cells (PANC‐1) using the Transwell system, adipocytes lost their lipid droplets and changed morphologically to fibroblast‐like cells (CAA). Adipocyte‐specific marker mRNA levels significantly decreased but those of fibroblast‐specific markers appeared, characteristic findings of CAA, as revealed by real‐time PCR. When PANC‐1 cells were cultured with CAA‐CM, significantly higher migration/invasion capability, chemoresistance, and epithelial‐mesenchymal transition (EMT) properties were observed compared with control cells. To investigate the mechanism underlying these effects, we performed microarray analysis of PANC‐1 cells cultured with CAA‐CM and found a 78.5‐fold higher expression of SAA1 compared with control cells. When the SAA1 gene in PANC‐1 cells was knocked down with SAA1 siRNA, migration/invasion capability, chemoresistance, and EMT properties were significantly attenuated compared with control cells. Immunohistochemical analysis on human pancreatic cancer tissues revealed positive SAA1 expression in 46/61 (75.4%). Overall survival in the SAA1‐positive group was significantly shorter than in the SAA1‐negative group (P = .013). In conclusion, we demonstrated that pancreatic cancer cells induced de‐differentiation in adipocytes toward CAA, and that CAA promoted malignant characteristics of pancreatic cancer via SAA1 expression, suggesting that SAA1 is a novel therapeutic target in pancreatic cancer.

1866-P: Peripancreatic Adipose Tissue Protects against Ectopic Fat Accumulation in the Liver

Peripancreatic adipose tissue (PAT) is an understudied visceral fat depot that surrounds pancreas and is in touch with spleen and liver. Recent previous studies suggest that obesity-associated PAT inflammation accelerates pancreatic neoplasia in KrasG12D mice and that PAT conditioned-medium from pre-diabetic rats (9 weeks on high-fat diet; HFD) stimulates insulin secretion, proliferation and apoptosis in INS-1 cells. In this study, we aimed to better characterize PAT functionality in the context of HFD-induced obesity. PAT is a very small depot (0,5 ±0,04 mg) with a relatively high number of small adipocytes in unchallenged mice on chow, and we found that PAT expansion is less pronounced at early stages of HFD-feeding compared to the expansion of inguinal (IWAT), gonadal (GWAT) and mesenteric adipose tissues (MWAT). After 8-weeks HFD feeding the expansion of PAT was however comparable to the other three fat depots, but still PAT was more protected against the deleterious effects of HFD on adipose tissue inflammation and insulin resistance as judged by gene expression analysis (adiponectin, insulin receptor and inflammation markers). Feeding after 16-weeks HFD reduced the glucose and lipid uptake in all fat depots however, it was less pronounced in PAT; both fatty acid and glucose oxidation rates were higher in PAT compared to IWAT, GWAT and MWAT. Moreover, we noted that PAT is the only fat depot where the tissue weight correlates positively with liver weight in HFD-induced obese mice, and surgical removal of PAT followed by 16-week-HFD-feeding was associated with increased hepatic triglyceride content and accumulation of more and larger lipid droplets. PAT did not regenerate during this 16-week HFD time course suggesting that its precursor cells reside within the depot. Taken all data together, we propose that PAT, although it is located in the visceral compartment, can be considered as a metabolically/immunologically healthy fat depot that protects against hepatic steatosis in advanced obesity. Disclosure B. Chanclón: None. P. Micallef: None. E. Banke Nordbeck: None. Y. Wu: None. B. Wilder: None. J. Kanerva: None. P. Rorsman: None. I. Wernstedt Asterholm: None.

Ressection of pancreatic carcinoma in the remnant pancreas after an R0 pancreaticoduodenectomy for papillary cancer: a case report

Introduction: We report a rare case of a repeated pancreatic resection in the remnant distal pancreas 18 months after a laparoscopic Whipple R0 procedure. In this case, the first surgery was for papillary cancer. Method: In February 2014, a 73-year-old woman underwent a laparoscopic Pancreatoduodenectomy procedure with lymphadenectomy for papillary cancer. In August 2015, in follow up segment MR revealed a tumor in the remnant pancreas. There were no findings of invasion of the surrounding tissue or distant metastasis. After radiological reevaluation (PET and CT) in October 2015, we removed the remnant pancreas and spleen also by laparoscopic surgery. Results: Histopathologically, the tumor was classified as a ductal adenocarcinoma, not the same tumor which had been removed during the first operation, with infiltration of peripancreatic adipose tissue and without lymph node metastasis. She was using Capecitabin after the surgery and in august 2016 peritoneal metastasis apears and died in september 2017. We compare the two histophatological diagnoses. Conclusions: There are very few reports of pancreatic carcinoma in the remnant pancreas after a pancreaticoduodenectomy in the literature. In most of these cases, it is for adenocarcinoma and even so difficult to assess whether the remnant pancreatic cancer is a recurrence or a second primary cancer. In our patient, the first hypothesis seems to be a new tumor.

Pancreatoduodenectomy with venous resection for pancreatic cancer does not improve the R0-rate

Introduction: Pancreatoduodenectomy with venous resection is considered standard of care in case of tumor involvement of the portal and/or superior mesenteric vein. It is performed with the aim of achieving an R0-resection. Methods: This prospective observational study included all patients undergoing pancreatoduodenectomy with or without venous resection for pancreatic cancer between January 2015 and October 2017 at Oslo University Hospital. Patients who received neoadjuvant chemotherapy were excluded. Detailed microscopic mapping of the tumour at the superior mesenteric vein (SMV)-groove was undertaken and results were compared between specimens with and without venous resection. Results: Ninety-five patients were included, of whom 25 had pancreatoduodenectomy with venous resection. R0-resection, based on >1 mm clearance, was achieved in 15 of 70 patients (21.4 %) without venous resection and in one of 25 patients (4 %) with venous resection (p=0.061). The SMV margin adjacent to the tethered vein was the most frequently involved margin in both groups (24 of 25, 96 % with venous resection, 35 of 70, 50 % without venous resection; p< 0.001). Microscopic mapping revealed that the broad invasive tumour front at the SMV-groove as well as the absence of peripancreatic adipose tissue at the SMV-margin were responsible for these findings. The transection margins of the venous resection itself were involved in only three of the 25 patients (12 %). Conclusion: R0-resection following pancreatoduodenectomy with venous resection can rarely be achieved due to involvement of the SMV-margin immediately adjacent to the resected vein.

Adipose tissue derived-factors impaired pancreatic β-cell function in diabetes

Inflammatory factors produced and secreted by adipose tissue, in particular peri-pancreatic adipose tissue (P-WAT), may influence pancreatic β-cell dysfunction. Using the ZDF Rat model of diabetes, we show the presence of infiltrating macrophage (ED1 staining) on pancreatic tissue and P-WAT in the pre-diabetes stage of the disease. Then, when the T2D is installed, infiltrating cells decreased. Meanwhile, the P-WAT conditioned-medium composition, in terms of inflammatory factors, varies during the onset of the T2D. Using chemiarray technology, we observed an over expression of CXCL-1, -2, -3, CCL-3/MIP-1α and CXCL-5/LIX and TIMP-1 in the 9 weeks old obese ZDF pre-diabetic rat model. Surprisingly, the expression profile of these factors decreased when animals become diabetic (12 weeks obese ZDF rats). The expression of these inflammatory proteins is highly associated with inflammatory infiltrate. P-WAT conditioned-medium from pre-diabetes rats stimulates insulin secretion, cellular proliferation and apoptosis of INS-1 cells. However, inhibition of conditioned-medium chemokines acting via CXCR2 receptor do not change cellular proliferation apoptosis and insulin secretion of INS-1 cells induced by P-WAT conditioned-medium. Taken together, these results show that among the secreted chemokines, increased expression of CXCL-1, -2, -3 and CXCL-5/LIX in P-WAT conditioned-medium is concomitant with the onset of the T2D but do not exerted a direct effect on pancreatic β-cell dysfunction.

Deficiencies in Natural Killer Cell Numbers, Expansion, and Function at the Pre-Neoplastic Stage of Pancreatic Cancer by KRAS Mutation in the Pancreas of Obese Mice.

The combined/synergistic effect of genetic mutation of KRAS in the pancreas and obesity, a life-style factor on suppression of natural killer (NK) cells at the pre-neoplastic stage of pancreatic cancer has not been investigated and is the subject of this report. Obese mice with KRAS (KC) mutation in the pancreas fed with high-fat calorie diet (HFCD) exhibit severe deficiencies in the NK cell expansion and function at the pre-neoplastic stage of pancreatic cancer. Decreased NK cell-mediated cytotoxicity is observed in the peripheral blood, spleen, pancreas, and peri-pancreatic adipose tissue in obese KC mice, whereas in bone marrow an increased NK cell-mediated cytotoxicity is observed when compared to lean WT mice fed with control diet (CD). Obese KC mice on HFCD demonstrated the least ability to expand NK cells or induce NK cell-mediated cytotoxicity when compared to the other groups of mice. Indeed, the following profile WT/CD > WT/HFCD > KC/CD > KC/HFCD was seen for the ability to expand NK cells or mediate cytotoxicity among four groups of mice in spleen, peripheral blood, pancreas, and peri-pancreatic adipose tissue. Sorted NK cells from the splenocytes of four groups of mice also exhibited the same profiles for the cytotoxicity as the unsorted splenocytes, and a decreased IFN-γ secretion could be seen in cultures of NK cells from KC mice fed with either CD or HFCD. Cultures of NK cells with autologous monocytes from obese KC mice fed with HFCD exhibited decreased cytotoxicity and IFN-γ secretion, whereas cultures of allogeneic NK cells from WT mice fed with CD with osteoclasts of obese mice fed with HFCD demonstrated decreased cytotoxicity but augmented IFN-γ secretion. Increased IL-6 along with decreased IFN-γ and cell-mediated cytotoxicity by the NK cells, within NK-adipose tissue of KC/HFCD mice, may provide safe microenvironment for the expansion of pancreatic tumors.

A difficult-to-treat case of pancreas divisum complicated by pancreatic pseudocyst

A 45-year-old male drinker, who was hospitalized for alcohol-induced acute pancreatitis 7 years ago, recently visited us after a day-long abdominal pain and vomiting. He was hospitalized for acutely-aggravated alcohol-induced chronic pancreatitis, with increased biliary pancreatic enzyme, increased concentration of peripancreatic adipose tissue and pancreatic pseudocyst found by abdominal CT. Pancreatic enzyme decreased by conservative treatment. We performed ERCP (10th day) and diagnosed pancreas divisum with cauda equina-like Wirsung duct by major-papilla imaging. As accessory pancreatic duct imaging from minor-papilla was difficult due to excessive inflammation, we reperformed ERCP (23rd day) . ENPD was placed because cystic lesion connecting with Santolini duct was found by minor-papilla imaging. After smaller pancreatic cyst was found by CT, pancreatic duct stent was placed (31st day) , and the patient was discharged. We report a case of pancreas divisum complicated by pancreatic pseudocyst.

The value of optical coherence tomography and morphometry in evaluating the peripancreatic adipose tissue in infected pancreatic necrosis

To investigate the morphometric and optical coherence tomography (OCT) characteristics of the microstructure of retroperitoneal peripancreatic adipose tissue during passive drainage and active perfusion-aspiration drainage for infected pancreatic necrosis. The authors analyzed 74 samples of peripancreatic adipose tissue obtained from 37 patients with passive (Group 1) and active perfusion-aspiration drainage (Group 2) of a focus of peripancreatitis. The tissues were examined with OCT, then fixed in a formalin solution and underwent histological examination, including morphometric one. The examined groups showed qualitative and quantitative differences in the tissue microstructure. In Group 1 samples, the proportion (median (upper quartile; lower quartile)) of interlobular connective tissue was 5.6 (3.9; 6.1)%; and that of adipocytes was 44.6 (41.2; 51.6)%. Necrotic tissue occupied 46.2 (35.6; 56.1)% of the area of specimens. The OCT images of necrotic tissue displayed a preponderance of unstructured regions with a high signal level while the parenchymal areas showed a cellular structured pattern. In Group 2 samples, the proportion of interlobular connective tissue was 16.2 (11.4; 19.7)%, and that of adipocytes was 68.5 (59.7; 71.2)%. At the same time, Group 2 exhibited necrosis - 14.4 (11.5; 19.2%) that was 3.2 times less than in Group 1. The OCT images of Group 2 samples showed a preponderance of cellular structured regions characteristic of the parenchyma, with pronounced stromal elements, which corresponded to the histological pattern. Active perfusion-aspiration drainage of peripancreatic adipose tissue versus passive drainage is associated with a smaller proportion of necrotic tissue (14.4% versus 46.2%; p≤0.05) and a larger proportion of a stromal vascular component (16.2% vs. 5.6%; p≤0.05). OCT could qualitatively distinguish viable fat tissue parenchyma from necrotic areas, without specially preparing the samples, which was confirmed by histomorphometric results.

Piscirickettsia salmonis infection in cultured lumpfish (Cyclopterus lumpus L.).

A Piscirickettsia salmonis infection was diagnosed in lumpfish (Cyclopterus lumpus L.) juveniles held in a marine research facility on the west coast of Ireland. The main clinical signs and pathology included marked ascites, severe multifocal liver necrosis and severe diffuse inflammation and necrosis of the exocrine pancreas and peri-pancreatic adipose tissue. Numerous Piscirickettsia-like organisms were observed by histopathology in the affected organs, and the bacterial species was characterized by molecular analysis. Sequencing of the partial 16S rDNA gene and internal transcribed spacer region showed the lumpfish sequences to be closely related to previously identified Atlantic salmon (Salmo salar L.) sequences from Ireland. To the authors' knowledge, this is the first detection of P.salmonis in lumpfish worldwide. The infection is considered potentially significant in terms of lumpfish health and biosecurity.

Extra-pancreatic invasion induces lipolytic and fibrotic changes in the adipose microenvironment, with released fatty acids enhancing the invasiveness of pancreatic cancer cells.

Pancreatic cancer progression involves components of the tumor microenvironment, including stellate cells, immune cells, endothelial cells, and the extracellular matrix. Although peripancreatic fat is the main stromal component involved in extra-pancreatic invasion, its roles in local invasion and metastasis of pancreatic cancer remain unclear. This study investigated the role of adipose tissue in pancreatic cancer progression using genetically engineered mice (Pdx1-Cre; LSL-KrasG12D; Trp53R172H/+) and an in vitro model of organotypic fat invasion. Mice fed a high fat diet had significantly larger primary pancreatic tumors and a significantly higher rate of distant organ metastasis than mice fed a standard diet. In the organotypic fat invasion model, pancreatic cancer cell clusters were smaller and more elongated in shape and showed increased fibrosis. Adipose tissue-derived conditioned medium enhanced pancreatic cancer cell invasiveness and gemcitabine resistance, as well as inducing morphologic changes in cancer cells and increasing the numbers of lipid droplets in their cytoplasm. The concentrations of oleic, palmitoleic, and linoleic acids were higher in adipose tissue-derived conditioned medium than in normal medium, with these fatty acids significantly enhancing the migration of cancer cells. Mature adipocytes were smaller and the concentration of fatty acids in the medium higher when these cells were co-cultured with cancer cells. These findings indicate that lipolytic and fibrotic changes in peripancreatic adipose tissue enhance local invasiveness and metastasis via adipocyte-released fatty acids. Inhibition of fatty acid uptake by cancer cells may be a novel therapy targeting interactions between cancer and stromal cells.

Peripancreatic adipose tissue inhibits the proliferation of pancreatic cancer cells and contributes chemoresistance

Peripancreatic adipose tissue inhibits the proliferation of pancreatic cancer cells and contributes chemoresistance

A 3D map of the islet routes throughout the healthy human pancreas.

Islets of Langerhans are fundamental in understanding diabetes. A healthy human pancreas from a donor has been used to asses various islet parameters and their three-dimensional distribution. Here we show that islets are spread gradually from the head up to the tail section of the pancreas in the form of contracted or dilated islet routes. We also report a particular anatomical structure, namely the cluster of islets. Our observations revealed a total of 11 islet clusters which comprise of small islets that surround large blood vessels. Additional observations in the peripancreatic adipose tissue have shown lymphoid-like nodes and blood vessels captured in a local inflammatory process. Our observations are based on regional slice maps of the pancreas, comprising of 5,423 islets. We also devised an index of sphericity which briefly indicates various islet shapes that are dominant throughout the pancreas.