MFG-E8 Maintains Cellular Homeostasis by Suppressing Endoplasmic Reticulum Stress in Pancreatic Exocrine Acinar Cells

Excessive endoplasmic reticulum (ER) stress contributes significantly to the pathogenesis of exocrine acinar damage in acute pancreatitis. Our previous study found that milk fat globule EGF factor 8 (MFG-E8), a lipophilic glycoprotein, alleviates acinar cell damage during AP via binding to αvβ3/5 integrins. Ligand-dependent integrin-FAK activation of STAT3 was reported to be of great importance for maintaining cellular homeostasis. However, MFG-E8’s role in ER stress in pancreatic exocrine acinar cells has not been evaluated. To study this, thapsigargin, brefeldin A, tunicamycin and cerulein + LPS were used to induce ER stress in rat pancreatic acinar cells in vitro. L-arginine- and cerulein + LPS-induced acute pancreatitis in mice were used to study ER stress in vivo. The results showed that MFG-E8 dose-dependently inhibited ER stress under both in vitro and in vivo conditions. MFG-E8 knockout mice suffered more severe ER stress and greater inflammatory response after L-arginine administration. Mechanistically, MFG-E8 increased phosphorylation of FAK and STAT3 in cerulein + LPS-treated pancreatic acinar cells. The presence of specific inhibitors of αvβ3/5 integrin, FAK or STAT3 abolished MFG-E8’s effect on cerulein + LPS-induced ER stress in pancreatic acinar cells. In conclusion, MFG-E8 maintains cellular homeostasis by alleviating ER stress in pancreatic exocrine acinar cells.

Eurytrema coelomaticum infection: correlation between parasite burden and impairment of pancreatic exocrine enzyme secretion

ABSTRACT: Eurytrema coelomaticum is a trematode reported in the pancreatic ducts of ruminants. It is conjectured that may cause disorders in the pancreas, as well as digestive and metabolic processes dependent on them. This study, determined if there is an impairment of exocrine pancreatic function, and correlated it with parasite burden. Pancreas, blood, and fecal samples were collected from 119 bovines at a abattoir. Stool samples were subjected to the gelatin and x-ray film digestion tests (to detect the presence of trypsin in feces). Using blood samples, the following biochemical tests were performed: amylase, lipase, glucose, fructosamine, cholesterol, triglycerides, total protein, albumin, and globulins. Analyses were correlated with pancreatic parasite burden. Cattle with a high parasitic load presented higher incidence of negative tests in both gelatin digestion and x-ray film digestion tests (P < 0.001) when compared to non-parasitized animals and those with a low parasitic load. Changes in those tests only occurred if the parasitemia was moderate or severe. The activity of the amylase and lipase enzymes was significantly higher in animals with low parasitemia (P < 0.05), compared to non-parasitized animals and with a high parasitic burden. In this study, in cases of high parasitemia, negative results were observed in both gelatin and x-ray film in the feces digestion tests. However, the low infection of E. coelomaticum, higher levels of serum amylase and lipase that also indicated loss of pancreatic exocrine functions were reported.

P-P17 Casting a Wider NET: Defining PEI in patients with Neuroendocrine Tumours using the 13C-MTG breath test

Background Somatostatin-analogues (SSAs) are the first-line treatment of unresectable, symptomatic neuroendocrine tumours (NETs). However, SSAs inhibit pancreatic secretions which could lead to pancreatic exocrine insufficiency (PEI). There is, however, very limited data regarding the physiologic link between SSAs and PEI. PEI negatively impacts patient quality of life (QoL), nutritional status, and clinical outcomes. This is a prospective, observational, cohort study to establish the impact of SSAs on pancreatic exocrine function in patients with NETs, using the 13C-Mixed-Triglyceride (13C-MTG) breath test. Methods Adult patients commencing SSA therapy for NETs, were recruited from December 2020. Patients were excluded if they had a diagnosis of other pancreatic disease, history of upper-gastrointestinal surgery that may alter pancreatic function, or already on SSA therapy. The impact of SSAs on exocrine function was assessed using the 13C-MTG breath test. A quotient of 13CO2/12CO2 was measured by mass spectrometry and the cumulative percent dose recovered at 6 hours (cPDR) is reported. Secondary endpoints investigated were changes in patient weight and Vitamin D levels. Results Exocrine function reduced in all patients (n = 7) following SSA therapy (median reduction from baseline: -22.2%, range: -5.6- -42.1%; p = 0.018) (Figure 1). Vitamin D levels decreased in all but one patient (median decrease from baseline: -11.7%, range: -29.3-10%; p = 0.126). Change in patient weight did not show any significant change (median decrease from baseline: -0.69%, range: -4.26 – 3.6%, p = 0.933). Conclusions SSA therapy appears to have a consistent impact on exocrine function from early in the treatment course. This suggests that there is a widespread underestimation of PEI in this setting. Whether such decrease in exocrine function leads to weight loss remains to be seen. Further studies are required to confirm this work, determine the clinical relevance of this observation, and optimise medical therapy of PEI in this cohort. The 13C-MTG breath test is a feasible and acceptable measure of pancreatic exocrine function in patients treated with SSA therapy for NETs.

P-P22 NET Profit: Considering quality of life assessment in patients treated with SSAs for NETs

Background Somatostatin Analogue (SSA) therapy of neuroendocrine tumours (NETs) leads to pancreatic exocrine insufficiency (PEI). PEI symptoms include diarrhoea, abdominal discomfort, bloating, and steatorrhea, which negatively impact quality of life (QoL). NETs (and the sequelae of carcinoid syndrome) however, have similar symptomatology to PEI, with a comparably negative impact on QoL. QoL tools exist to assess PEI and its response to enzyme therapy; however, we hypothesise that PEI symptom scale scores will be unreliable in SSA-induced PEI due to the concurrent improvement of the carcinoid symptoms. Methods Adult patients commencing SSA therapy for NETs were recruited from December 2020. Qualitative assessments of the impact of SSAs and pancreatic exocrine function on patient QoL were performed before and during (at 8 weeks) therapy. The Pancreatic Exocrine Insufficiency Questionnaire (PEI-Q) was used to capture patient-reported assessment of relevant symptoms. Health-related QoL was assessed using the European Organisation Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLC)-C30, supplemented by the EORTC GI.NET.21. Patients were specifically asked about steatorrhea at both assessments. Results Seven patients completed the study. 5-HIAA levels were raised in 4/7 patients, indicative of carcinoid syndrome, secondary to the NET. Pancreatic exocrine function reduced after SSA therapy in all patients (data reported elsewhere) but paradoxically PEI-Q symptom scale scores reduced (median decrease from baseline: -18.5%, range: -1.5- -55.6%; p = 0.018) (Figure 1). According to PEI-Q, all seven patients would meet the criteria for a mild PEI at baseline, and two would be considered severe. One patient reported steatorrhea after commencing SSA-therapy. No changes in relevant domains of EORTC questionnaires were statistically significant, including functional, symptomatic, and overall health scores. Conclusions The PEI-Q tool is not useful for assessing SSA-related PEI due to substantial symptom overlap with the tumour itself and SSA therapy. The decrease in symptom score is likely due to improvement of carcinoid syndrome, independent of PEI. Although the cardinal PEI symptom is steatorrhea, there is no distinction between that and diarrhoea in the EORTC tool, and confounding aetiologies of diarrhoea in NET patients may further complicate assessment. Current available QoL measures are of limited use in the setting of SSA-related PEI, and care should be taken if evaluating PEI or response of PEI to treatment.

Two new mutations in the CEL gene causing diabetes and hereditary pancreatitis: How to correctly identify MODY8 cases

Objective Maturity-onset diabetes of the young, type 8 (MODY8) is associated with mutations in the CEL gene, which encodes the digestive enzyme carboxyl ester lipase. Several diabetes cases and families have in recent years been attributed to mutations in CEL without any functional or clinical evidence provided. To facilitate correct MODY8 diagnostics, we screened two cohorts of diabetes patients and delineated the phenotype. Research design Young, lean Swedish and Finnish patients with a diagnosis of type 2 diabetes (352 cases, 406 controls) were screened for mutations in the CEL gene. We also screened 58 Czech MODY cases who had tested negative for common MODY genes. For CEL mutation-positive subjects, family history was recorded, and clinical investigations and pancreatic imaging performed. Results One Swedish and one Czech case with germline mutation in CEL were identified. Clinical and radiological investigations of these two probands and their families revealed dominantly inherited insulin-dependent diabetes, pancreatic exocrine dysfunction and atrophic pancreas with lipomatosis and cysts. Notably, hereditary pancreatitis was the predominant phenotype in one pedigree. Both families carried single-base pair deletions in the proximal part of the CEL variable number of tandem repeat (VNTR) region in exon 11. The mutations are predicted to lead to aberrant protein tails that make the CEL protein susceptible to aggregation. Conclusions The diagnosis of MODY8 requires a pancreatic exocrine phenotype and a deletion in the CEL VNTR in addition to dominantly inherited diabetes. CEL screening may be warranted also in families with hereditary pancreatitis of unknown genetic etiology.