Relationships among iron, protein oxidation and lipid peroxidation levels in rats with alcohol-induced acute pancreatitis

The melatonin receptor agonist agomelatine protects against acute pancreatitis induced by cadmium by attenuating inflammation and oxidative stress and modulating Nrf2/HO-1 pathway

Pancreatitis is a serious effect of the heavy metal cadmium (Cd) and inflammation and oxidative stress (OS) are implicated in Cd-induced pancreatic injury. This study evaluated the effect of the melatonin receptor agonist agomelatine (AGM) on Cd-induced acute pancreatitis (AP), pointing to its modulatory effect on inflammation, OS, and Nrf2/HO-1 pathway. Rats were supplemented with AGM orally for 14 days and a single injection of cadmium chloride (CdCl2) on day 7. Cd increased serum amylase and lipase and caused pancreatic endocrine and exocrine tissue injury. Malondialdehyde (MDA), nitric oxide (NO) and myeloperoxidase (MPO) were elevated, nuclear factor (NF)-kB p65, inducible NO synthase (iNOS), interleukin (IL)-6, tumor necrosis factor (TNF)-α and CD40 were upregulated, and antioxidants were decreased in the pancreas of Cd-administered rats. AGM ameliorated serum amylase and lipase and pancreatic OS, NF-kB p65, CD40, pro-inflammatory mediators and caspase-3, prevented tissue injury and enhanced antioxidants. AGM downregulated Keap1 and enhanced Nrf2 and HO-1 in the pancreas of Cd-administered rats. In silico findings revealed the binding affinity of AGM with Keap1, HO-1, CD40L and caspase-3. In conclusion, AGM protected against AP induced by Cd by preventing inflammation, OS and apoptosis and modulating Nrf2/HO-1 pathway.

An in-Depth Exploration of the Genetic Interaction Network Between Ferroptosis and Acute Pancreatitis

Background

Ferroptosis plays an important role in a variety of disease processes and is equally important in pancreatic diseases. However, the role of ferroptosis-related genes (FRGs) in acute pancreatitis (AP) remains unknown, and their specific potential mechanisms still need to be explored extensively.

Methods

AP-related gene microarray data were obtained from the GEO database, while FRGs were obtained from the ferroptosis database (FerrDb). Differentially expressed genes (DEGs) were screened by the "limma" package, and GSEA was performed. The corresponding ferroptosis-related differentially expressed genes (FRDEGs) were screened, and GO and KEGG pathway analyses were performed. A PPI network was constructed to identify hub FRDEGs by CytoHubba, MCODE and CTD scores. Transcription factors and miRNAs predicted using the NetworkAnalyst database were used to establish the regulatory network. Immune cell infiltration analysis was performed by the R package "ssGSEA" algorithm. The hub genes were validated by transcriptome sequencing of AP model mice and immunohistochemistry in rats and mice.

Results

A total of 82 FRDEGs were screened, and these genes were mainly associated with ferroptosis, hypoxic response, autophagy, mitophagy and immune inflammation. However, we also found that these genes are also jointly involved in other cell death modalities, such as apoptosis and necroptosis. Further analysis obtained 7 hub genes from 82 genes, and single-sample gene set enrichment analysis (ssGSEA) showed that the hub genes are closely associated with the infiltration of specific immune cells and the activation of immune pathways.

Conclusion

This study reveals the complex functions and important roles of ferroptosis-related genes in AP and provides gene targets for further studies of AP.

Iron metabolism and the exocrine pancreas

Although the pathophysiological mechanisms and consequences of gross derangements in iron metabolism are well known, little is known about the pathophysiological mechanisms underlying mild-to-moderate alterations in iron metabolism and their consequences. Growing evidence indicates that the exocrine pancreas has a bidirectional relationship with iron metabolism. Studies have shown alterations in circulating markers of iron metabolism, iron absorption, and intra-pancreatic iron deposition in pancreatitis. At the same time, exocrine pancreatic dysfunction has been shown in iron overload disorders. These observations reveal a compelling connection between the exocrine pancreas and iron metabolism, which are further elucidated by observations of therapeutic benefits of iron chelating agents and pancreatic enzyme replacement therapy. While the pancreas is not a major reservoir of iron in the body, better understanding of its relationship with iron metabolism may yield unexpected insights.

Murine Models of Acute Pancreatitis: A Critical Appraisal of Clinical Relevance

Acute pancreatitis (AP) is a severe disease associated with high morbidity and mortality. Clinical studies can provide some data concerning the etiology, pathophysiology, and outcomes of this disease. However, the study of early events and new targeted therapies cannot be performed on humans due to ethical reasons. Experimental murine models can be used in the understanding of the pancreatic inflammation, because they are able to closely mimic the main features of human AP, namely their histologic glandular changes and distant organ failure. These models continue to be important research tools for the reproduction of the etiological, environmental, and genetic factors associated with the pathogenesis of this inflammatory pathology and the exploration of novel therapeutic options. This review provides an overview of several murine models of AP. Furthermore, special focus is made on the most frequently carried out models, the protocols used, and their advantages and limitations. Finally, examples are provided of the use of these models to improve knowledge of the mechanisms involved in the pathogenesis, identify new biomarkers of severity, and develop new targeted therapies.

Serum paraoxonase (a high-density lipoprotein-associated lipophilic antioxidant) activity in clinical follow-up of patients with acute pancreatitis, with particular emphasis on oxidative stress parameters and lipid profile: a prospective pilot trial

The purpose of this study was to investigate the possible role of PON-1, an antioxidant lipophilic enzyme linked to HDL-C (high-density lipoprotein cholesterol), on the pathophysiology and clinical follow-up of acute pancreatitis. Biochemical tests, PON-1 and oxidative stress parameters (malonyl dialdehyde, MDA; superoxide dismutase, SOD; total antioxidant capacity, TAC) were evaluated in the sera of patients with acute pancreatitis at admission (day 0), day 3 and day 10 of follow-up, between June and September 2017. SPSS 13.0 statistical software package programme was used for statistical analyses.Mean age was 51.4 of the total 25 patients. Ranson scores were 0-1 points (60%), 3-4 points (24%) and 5-6 points (16%). CTSI (computed tomography severity index) scores were calculated, and most of the patients were seen to have mild or average pancreatitis (96%). While total cholesterol, triacylglycerol and LDL-C (low-density lipoprotein) levels stayed in their normal limits, there was a significant decrement tendency. HDL-C level was seen to rise significantly above its upper limit at day 10 (p < 0.001). Mean PON-1 levels were measured as 69.23, 76.72 vs. 113.15 U/mL at days 0, 3 and 10, respectively; and it was positively correlated with HDL-C (p < 0.001). Serum SOD increased also in parallel with PON-1 (20.49 vs. 39.46 U/mL) while MDA level decreased significantly (3.9 vs. 2.28 μM, p < 0.001). TAC was seen to rise significantly after treatment (0.52 vs. 1.22 mM). In conclusion, decreased PON-1 and HDL-C together with antioxidants SOD and TAC at the early period of acute pancreatitis were seen to rise after treatment, while the previously higher MDA level decreased in parallel. This reveals the importance of the balance between oxidative stress and antioxidant defense mechanisms in clinical progression of the disease, and the potential of PON-1 as a promising clinical marker.

Ischemia-reperfusion rat model of acute pancreatitis: protein carbonyl as a putative early biomarker of pancreatic injury

Acute pancreatitis (AP) is an inflammatory disorder that can affect adjacent and/or remote organs. Some evidence indicates that the production of reactive oxygen species is able to induce AP. Protein carbonyl (PC) derivatives, which can also be generated through oxidative cleavage mechanisms, have been implicated in several diseases, but there is little or no information on this biomarker in AP. We investigated the association between some inflammatory mediators and PC, with the severity of ischemia-reperfusion AP. Wistar rats (n = 56) were randomly assigned in the following groups : control; sham, 15- or 180-min clamping of splenic artery, with 24 or 72 h of follow-up. The relationships between serum level of PC and thiobarbituric acid reactive species (TBARS) to myeloperoxidase (MPO) activity in tissue homogenates and to cytokines in culture supernatants of pancreatic samples were analyzed. MPO activity was related to the histology scores and increased in all clamping groups. Tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL-1β), and interleukin-6 were higher in the 180-min groups. Significant correlations were found between MPO activity and the concentrations of TNF-α and IL-1β. PC levels increased in the 15-min to 24-h group. TBARS levels were not altered substantially. MPO activity and TNF-α and IL-1β concentrations in pancreatic tissue are correlated with AP severity. Serum levels of PC appear to begin to rise early in the course of the ischemia-reperfusion AP and are no longer detected at later stages in the absence of severe pancreatitis. These data suggest that PC can be an efficient tool for the diagnosis of early stages of AP.

Alcoholic acute pancreatitis: pathogenesis and clinical characteristics

Animal and clinical studies have shown that alcohol and its metabolic products, endotoxin, viral infection, drinking pattern, smoking, obesity, genetic variability, and gene polymorphisms were very important in the pathogenesis of alcoholic acute pancreatitis (AAP). The morbidity of AAP has been increased in the past decade, and male gender is strongly associated with increased risk of AAP. The mortality of AAP is high, while the quality of life of survivors of severe AAP is low. In this paper, we review the pathogenesis and clinical characteristics of AAP.