Azithromycin does not improve disease severity in acute experimental pancreatitis.

Acute pancreatitis is a severe systemic disease triggered by a sterile inflammation and initial local tissue damage of the pancreas. Immune cells infiltrating into the pancreas are main mediators of acute pancreatitis pathogenesis. In addition to their antimicrobial potency, macrolides possess anti-inflammatory and immunomodulatory properties which are routinely used in patients with chronic airway infections and might also beneficial in the treatment of acute lung injury. We here tested the hypothesis that the macrolide antibiotic azithromycin can improve the course of acute experimental pancreatitis via ameliorating the damage imposed by sterile inflammation, and could be used as a disease specific therapy. However, our data show that azithromycin does not have influence on caerulein induced acute pancreatitis in terms of reduction of organ damage, and disease severity. Furthermore Infiltration of immune cells into the pancreas or the lungs was not attenuated by azithromycin as compared to controls or ampicillin treated animals with acute experimental pancreatitis. We conclude that in the chosen model, azithromycin does not have any beneficial effects and that its immunomodulatory properties cannot be used to decrease disease severity in the model of caerulein-induced pancreatitis in mice.

Necessity of transnasal gastroscopy in routine diagnostics: a patient-centred requirement analysis.

INTRODUCTION: Numerous indications require regular upper gastrointestinal endoscopy (oesophagogastroduodenoscopy; EGD) in outpatients. In most cases, peroral gastroscopy is performed. The aim of this study was to evaluate the need of transnasal gastroscopy (nEGD) in outpatients. METHODS: A questionnaire was used to assess patients' preferred choice of method, previous experience with EGD, psychological aspects and sociodemographic data. Furthermore, patient satisfaction with and potentially perceived discomfort during the examination as well as preference for a method in regard to future examinations was evaluated. RESULTS: From September 2016 to March 2017, a total of 283 outpatients at endoscopy of the University Hospital of Leipzig were approached to participate in the study. 196 patients were eligible, of whom 116 (60%) chose nEGD. For 87 patients (87/283, 31%) nEGD had to be excluded for medical reasons. The average age in the total sample was 53 (±17) years. 147 (77%) have had previous experience with peroral EGD (oEGD). Of the nEGD examined patients 83% were fairly up to extremely satisfied with the procedure. Satisfaction significantly predicted the choice of future EGD examinations. Nasal pain experienced during nEGDs was associated with rejection of nEGD in further EGD examinations (p<0.01). Patients who did choose a specific procedure were more likely to select the same procedure as their future preference (χ²= 73.6, df=1, p<0.001); this preference was unaffected by the procedure that had been chosen previously (reselecting nEGD: 84%, oEGD: 89%, p=0.874). CONCLUSION: nEGD without sedation is a viable alternative. Patient satisfaction with nEGD is high, and reselection rate for nEGD is similar to that for oEGD. As a result of this study nEGD is now offered as a routine procedure at the University of Leipzig. TRIAL REGISTRATION NUMBER: NCT03663491.

p8 deficiency leads to elevated pancreatic beta cell mass but does not contribute to insulin resistance in mice fed with high-fat diet.

BACKGROUND: p8 was initially described as being overexpressed in acute pancreatitis and encoding a ubiquitous stress protein. Analysis of insulin sensitivity and glucose tolerance in p8-knockout and haplodeficient mice revealed counterintuitive results. Thus, we determined glycemic control of p8 in mice fed with standard (SD) and high-fat diet (HFD). METHODS: p8-/- and wild type (p8+/+) mice were used for analysis of glucagon (immunohistochemistry), insulin levels (ELISA) and beta cell mass. Hyperinsulinemic- euglycemic glucose clamp technique, i.p. glucose tolerance test (ipGTT), i.p. insulin tolerance test (ipITT) and metabolic chamber analysis were performed in SD (4% fat) and HFD (55% fat) groups. RESULTS: p8-/- mice showed no differences in glucagon or insulin content but higher insulin secretion from pancreatic islets upon glucose stimulation. p8 deficiency resulted in elevated beta cell mass but was not associated with increased insulin resistance in ipGTT or ipITT. Glucose clamp tests also revealed no evidence of association of p8 deficiency with insulin resistance. Metabolic chamber analysis showed equal energy expenditure in p8-/- mice and wild type animals. CONCLUSION: p8 depletion may contribute to glucose metabolism via stress-induced insulin production and elevated beta cell mass. Nevertheless, p8 knockout showed no impact on insulin resistance in SD and HFD-fed mice.

Immune dysregulation in patients with PTEN hamartoma tumor syndrome: Analysis of FOXP3 regulatory T cells.

BACKGROUND: Patients with heterozygous germline mutations in phosphatase and tensin homolog deleted on chromosome 10 (PTEN) experience autoimmunity and lymphoid hyperplasia. OBJECTIVES: Because regulation of the phosphoinositide 3-kinase (PI3K) pathway is critical for maintaining regulatory T (Treg) cell functions, we investigate Treg cells in patients with heterozygous germline PTEN mutations (PTEN hamartoma tumor syndrome [PHTS]). METHODS: Patients with PHTS were assessed for immunologic conditions, lymphocyte subsets, forkhead box P3 (FOXP3)+ Treg cell levels, and phenotype. To determine the functional importance of phosphatases that control the PI3K pathway, we assessed Treg cell induction in vitro, mitochondrial depolarization, and recruitment of PTEN to the immunologic synapse. RESULTS: Autoimmunity and peripheral lymphoid hyperplasia were found in 43% of 79 patients with PHTS. Immune dysregulation in patients with PHTS included lymphopenia, CD4+ T-cell reduction, and changes in T- and B-cell subsets. Although total CD4+FOXP3+ Treg cell numbers are reduced, frequencies are maintained in the blood and intestine. Despite pathogenic PTEN mutations, the FOXP3+ T cells are phenotypically normal. We show that the phosphatase PH domain leucine-rich repeat protein phosphatase (PHLPP) downstream of PTEN is highly expressed in normal human Treg cells and provides complementary phosphatase activity. PHLPP is indispensable for the differentiation of induced Treg cells in vitro and Treg cell mitochondrial fitness. PTEN and PHLPP form a phosphatase network that is polarized at the immunologic synapse. CONCLUSION: Heterozygous loss of function of PTEN in human subjects has a significant effect on T- and B-cell immunity. Assembly of the PTEN-PHLPP phosphatase network allows coordinated phosphatase activities at the site of T-cell receptor activation, which is important for limiting PI3K hyperactivation in Treg cells despite PTEN haploinsufficiency.

Loss of Bace1 in mice does not alter the severity of caerulein induced pancreatitis.

CONTEXT: Beta-site alpha-amyloid protein cleaving enzyme1 (BACE1) plays a key role in the pathogenesis of Alzheimer's disease. Additional to its moderate expression in the brain, high levels of BACE1 mRNA were found in the pancreas. Murine Bace1 has been immunohistochemicaly detected at the apical pole of acinar cells within the exocrine pancreas of mice and Bace1 activity was observed in pancreatic juice. In vitro experiments revealed enteropeptidase as a putative substrate for Bace1 suggesting a role in acute pancreatitis. OBJECTIVE: The aim of this study was to address a protective mechanism of Bace1 in acute experimental pancreatitis in mice. METHODS: Acute experimental pancreatitis was induced by intraperitoneal injection of caerulein in homozygote Bace1-/- mice and wild type mice. Serum and tissue analyses were carried out after 4 h, 8 h and 24 h. Measurement of plasma amylase and lipase was performed to confirm pancreatitis induction. In order to assess the severity of pancreatitis H&E stained pancreatic sections were examined regarding edema, inflammation and apoptosis. Immunohistochemical detection of myeloperoxidase (MPO) positive cells was carried out to further quantify the extent of inflammation. Expression of Bace2 within the pancreas was analyzed by immunohistochemistry and RT-qPCR. RESULTS: We demonstrate that total loss of Bace1 in mice leads to no alterations in the course of acute experimental caerulein-pancreatitis. Bace1-/- mice develop a moderate pancreatitis that is comparable in histomorphological and serological features with those seen in wild type mice. DISCUSSION: We discuss the results in the context of the applied caerulein induced edematous pancreatitis model and possible compensatory mechanisms via Bace2 that might be responsible for the observed results.

Autoimmunity, intestinal lymphoid hyperplasia, and defects in mucosal B-cell homeostasis in patients with PTEN hamartoma tumor syndrome.

The Phosphatase And Tensin Homolog Deleted On Chromosome 10 (PTEN) regulates the phosphoinositol-3-kinase (PI3K)-AKT signaling pathway. In a series of 34 patients with PTEN mutations, we described gastrointestinal lymphoid hyperplasia, extensive hyperplastic tonsils, thymus hyperplasia, autoimmune lymphocytic thyroiditis, autoimmune hemolytic anemia, and colitis. Functional analysis of the gastrointestinal mucosa-associated lymphoid tissue revealed increased signaling via the PI3K-AKT pathway, including phosphorylation of S6 and increased cell proliferation, but also reduced apoptosis of CD20(+)CD10(+) B cells. Reduced activity of PTEN therefore affects homeostasis of human germinal center B cells by increasing PI3K-AKT signaling via mammalian target of rapamycin as well as antiapoptotic signals.