John George

Morphine worsens the severity and prevents pancreatic regeneration in mouse models of acute pancreatitis

Background Opioids such as morphine are widely used for the management of pain associated with acute pancreatitis. Interestingly, opioids are also known to affect the immune system and modulate inflammatory pathways in non-pancreatic diseases. However, the impact of morphine on the progression of acute pancreatitis has never been evaluated. In the current study, we evaluated the impact of morphine on the progression and severity of acute pancreatitis. Methods Effect of morphine treatment on acute pancreatitis in caerulein, L-arginine and ethanol–palmitoleic acid models was evaluated after induction of the disease. Inflammatory response, gut permeability and bacterial translocation were compared. Experiments were repeated in mu (µ) opioid receptor knockout mice (MORKO) and in wild-type mice in the presence of opioid receptor antagonist naltrexone to evaluate the role of µ-opioid receptors in morphine’s effect on acute pancreatitis. Effect of morphine treatment on pathways activated during pancreatic regeneration like sonic Hedgehog and activation of embryonic transcription factors like pdx-1 and ptf-1 were measured by immunofluorescence and quantitative PCR. Results Histological data show that treatment with morphine after induction of acute pancreatitis exacerbates the disease with increased pancreatic neutrophilic infiltration and necrosis in all three models of acute pancreatitis. Morphine also exacerbated acute pancreatitis-induced gut permeabilisation and bacteraemia. These effects were antagonised in the MORKO mice or in the presence of naltrexone suggesting that morphine’s effect on severity of acute pancreatitis are mediated through the µ-opioid receptors. Morphine treatment delayed macrophage infiltration, sonic Hedgehog pathway activation and expression of pdx-1 and ptf-1. Conclusion Morphine treatment worsens the severity of acute pancreatitis and delays resolution and regeneration. Considering our results, the safety of morphine for analgesia during acute pancreatitis should be re-evaluated in future human studies.

Comprehensive analysis of microRNA signature of mouse pancreatic acini: overexpression of miR-21-3p in acute pancreatitis

In the current study, we have characterized the global miRNA expression profile in mouse pancreatic acinar cells and during acute pancreatitis using next-generation RNA sequencing. We identified 324 known and six novel miRNAs that are expressed in mouse pancreatic acinar cells. In the basal state, miR-148a-3p, miR-375-3p, miR-217-5p, and miR-200a-3p were among the most abundantly expressed, whereas miR-24-5p and miR-421-3p were the least abundant. Treatment of acinar cells with caerulein (100 nM) and taurolithocholic acid 3-sulfate [TLC-S (250 μM)] induced numerous changes in miRNA expression profile. In particular, we found significant overexpression of miR-21-3p in acini treated with caerulein and TLC-S. We further looked at the expression of miR-21-3p in caerulein, l-arginine, and caerulein + LPS-induced acute pancreatitis mouse models and found 12-, 21-, and 50-fold increased expression in the pancreas, respectively. In summary, this is the first comprehensive analysis of global miRNA expression profile of mouse pancreatic acinar cells in normal and disease conditions. Our analysis shows that miR-21-3p expression level correlates with the severity of the disease.

Dynamic equilibrium of heterogeneous and interconvertible multipotent hematopoietic cell subsets

Populations of hematopoietic stem cells and progenitors are quite heterogeneous and consist of multiple cell subsets with distinct phenotypic and functional characteristics. Some of these subsets also appear to be interconvertible and oscillate between functionally distinct states. The multipotent hematopoietic cell line EML has emerged as a unique model to study the heterogeneity and interconvertibility of multipotent hematopoietic cells. Here we describe extensive phenotypic and functional heterogeneity of EML cells which stems from the coexistence of multiple cell subsets. Each of these subsets is phenotypically and functionally heterogeneous, and displays distinct multilineage differentiation potential, cell cycle profile, proliferation kinetics, and expression pattern of HSC markers and some of the key lineage-associated transcription factors. Analysis of their maintenance revealed that on a population level all EML cell subsets exhibit cell-autonomous interconvertible properties, with the capacity to generate all other subsets and re-establish complete parental EML cell population. Moreover, all EML cell subsets generated during multiple cell generations maintain their distinct phenotypic and functional signatures and interconvertible properties. The model of EML cell line suggests that interconvertible multipotent hematopoietic cell subsets coexist in a homeostatically maintained dynamic equilibrium which is regulated by currently unknown cell-intrinsic mechanisms.

Indomethacin to Post–Endoscopic Retrograde Cholangiopancreatography Pancreatitis: When and How?

1 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 Dear Editors: Postprocedure pancreatitis is the most common complication of endoscopic retrograde cholangiopancreatography (ERCP) and is associated with a prolonged hospital stay and at times high morbidity and mortality. Extensive randomized clinical trials have evaluated systematically the potential risk reduction of post-ERCP pancreatitis by pharmacologic prophylaxis with indomethacin. Recent major clinical evidence generally supports the use of rectal administration of indomethacin for post-ERCP prophylaxis. However, variables like timing (preprocedure and periprocedure vs postprocedure), route (oral vs rectal vs combined) and patient selection (high risk vs universal) needs to be further evaluated systematically to improve the outcomes of patients post-ERCP. We read with great interest the recent articles of postERCP pancreatitis published in Gastroenterology. This large retrospective study by Thiruvengadam et al showed an overall decrease in incidence and severity of post-ERCP pancreatitis in a varied retrospective cohort of patients undergoing ERCP over a 7-year period. Rectal indomethacin was administered routinely in the last 3.5 years of the study period and was associated with an odds ratio of 0.35 (95% confidence interval, 0.24-0.51) for post-ERCP pancreatitis overall and 0.17 (95% confidence interval, 0.09-0.32) for moderate to severe post-ERCP pancreatitis. However, a recent randomized control study by Levenick et al concluded that rectal indomethacin did not prevent postERCP pancreatitis. This difference could be explained potentially by differences in patient selection, the overall incidence of post-ERCP pancreatitis, and differences in endoscopic interventions among various clinical trials. A recent randomized control trial from China by Luo et al used preprocedural administration of rectal indomethacin in all unselected patients and compared it with risk-stratified postprocedural administration in a high-risk group. It is interesting to observe that post-ERCP pancreatitis occurred in in 18 of 305 high-risk patients (6%) in the universal group and 35 of 281 high-risk patients (12%) in the risk-stratified group. The overall incidence of post-ERCP pancreatitis was significantly less in the preprocedure group, namely, 47 of 1297 (4%) compared with postprocedure administration, namely, 100 of 1303 (8%) in the risk-stratified groups. These data clearly suggest that universal preprocedural indomethacin reduced the overall risk of post-ERCP pancreatitis without increasing the risk of bleeding. Given that plasma levels peak around 30 to 60 minutes after rectal administration, preprocedural