Docosahexaenoic Acid Inhibits Expression of Fibrotic Mediators in Mice With Chronic Pancreatitis

Differences in Plasma Fatty Acid Composition Related to Chronic Pancreatitis: A Pilot Study

OBJECTIVES

Chronic pancreatitis (CP) is an inflammatory disease affecting the absorption of fat-soluble nutrients. Signaling in pancreatic cells that lead to inflammation may be influenced by fatty acids (FAs) through diet and de novo lipogenesis. Here, we investigated the relationship between plasma FA composition in CP with heterogeneity of etiology and complications of CP.

MATERIALS AND METHODS

Blood and clinical parameters were collected from subjects with CP (n = 47) and controls (n = 22). Plasma was analyzed for FA composition using gas chromatography and compared between controls and CP and within CP.

RESULTS

Palmitic acid increased, and linoleic acid decreased in CP compared with controls. Correlations between age or body mass index and FAs are altered in CP compared with controls. Diabetes, pancreatic calcifications, and substance usage, but not exocrine pancreatic dysfunction, were associated with differences in oleic acid and linoleic acid relative abundance in CP. De novo lipogenesis index was increased in the plasma of subjects with CP compared with controls and in calcific CP compared with noncalcific CP.

CONCLUSIONS

Fatty acids that are markers of de novo lipogenesis and linoleic acid are dysregulated in CP depending on the etiology or complication. These results enhance our understanding of CP and highlight potential pathways targeting FAs for treating CP.

Ferroptosis in Rat Lung Tissue during Severe Acute Pancreatitis-Associated Acute Lung Injury: Protection of Qingyi Decoction

Qingyi decoction (QYD) has anti-inflammatory pharmacological properties and substantial therapeutic benefits on severe acute pancreatitis (SAP) in clinical practice. However, its protective mechanism against SAP-associated acute lung injury (ALI) remains unclear. In this study, we screened the active ingredients of QYD from the perspective of network pharmacology to identify its core targets and signaling pathways against SAP-associated ALI. Rescue experiments were used to determine the relationship between QYD and ferroptosis. Then, metabolomics and 16s rDNA sequencing were used to identify differential metabolites and microbes in lung tissue. Correlation analysis was utilized to explore the relationship between core targets, signaling pathways, metabolic phenotypes, and microbial flora, sorting out the potential molecular network of QYD against SAP-associated lung ALI. Inflammatory damage was caused by SAP in the rat lung. QYD could effectively alleviate lung injury, improve respiratory function, and significantly reduce serum inflammatory factor levels in SAP rats. Network pharmacology and molecular docking identified three key targets: ALDH2, AnxA1, and ICAM-1. Mechanistically, QYD may inhibit ferroptosis by promoting the ALDH2 expression and suppress neutrophil infiltration by blocking the cleavage of intact AnxA1 and downregulating ICAM-1 expression. Ferroptosis activator counteracts the pulmonary protective effect of QYD in SAP rats. In addition, seven significant differential metabolites were identified in lung tissues. QYD relatively improved the lung microbiome's abundance in SAP rats. Further correlation analysis determined the correlation between ferroptosis, differential metabolites, and differential microbes. In this work, the network pharmacology, metabolomics, and 16s rDNA sequencing were integrated to uncover the mechanism of QYD against SAP-associated ALI. This novel integrated method may play an important role in future research on traditional Chinese medicine.

Induction of pancreatitis in mice with susceptibility to pancreatic cancer

Chronic inflammation is known to be associated with pancreatic cancer, however a complete picture regarding how these pathologies intersect is still being characterized. In vivo model systems are critical for the study of mechanisms underlying how inflammation accelerates neoplasia. Repeat injection of cerulein, a cholecystokinin (CCK) analog, is widely used to experimentally induce acute and chronic pancreatitis in vivo. Chronic cerulein administration into genetically engineered mouse models (GEMMs) with predisposition to pancreatic cancer can induce a pro-inflammatory immune response, pancreatic acinar cell damage, pancreatic stellate cell activation, and accelerate the onset of neoplasia. Here we provide a detailed protocol and insights into using cerulein to induce pancreatitis in GEMMs, and methods to experimentally assess inflammation and pancreatic neoplasia.

Docosahexaenoic Acid Inhibits Cytokine Expression by Reducing Reactive Oxygen Species in Pancreatic Stellate Cells

Pancreatic stellate cells (PSCs) are activated by inflammatory stimuli, such as TNF-α or viral infection. Activated PSCs play a crucial role in the development of chronic pancreatitis. Polyinosinic-polycytidylic acid (poly (I:C)) is structurally similar to double-stranded RNA and mimics viral infection. Docosahexaenoic acid (DHA) exhibits anti-inflammatory activity. It inhibited fibrotic mediators and reduced NF-κB activity in the pancreas of mice with chronic pancreatitis. The present study aimed to investigate whether DHA could suppress cytokine expression in PSCs isolated from rats. Cells were pre-treated with DHA or the antioxidant N-acetylcysteine (NAC) and stimulated with TNF-α or poly (I:C). Treatment with TNF-α or poly (I:C) increased the expression of monocyte chemoattractant protein 1 (MCP-1) and chemokine C-X3-C motif ligand 1 (CX3CL1), which are known chemoattractants, and enhanced intracellular and mitochondrial reactive oxygen species (ROS) production and NF-κB activity, but reduced mitochondrial membrane potential (MMP). Increased intracellular and mitochondrial ROS accumulation, cytokine expression, MMP disruption, and NF-κB activation were all prevented by DHA in TNF-α- or poly (I:C)-treated PSCs. NAC suppressed TNF-α- or poly (I:C)-induced expression of MCP-1 and CX3CL1. In conclusion, DHA inhibits poly (I:C)- or TNF-α-induced cytokine expression and NF-κB activation by reducing intracellular and mitochondrial ROS in PSCs. Consumption of DHA-rich foods may be beneficial in preventing chronic pancreatitis by inhibiting cytokine expression in PSCs.