Docosahexaenoic Acid Inhibits Cerulein-Induced Acute Pancreatitis in Rats

Algal Oil Mitigates Sodium Taurocholate-Induced Pancreatitis by Alleviating Calcium Overload, Oxidative Stress, and NF-κB Activation in Pancreatic Acinar Cells

Acute pancreatitis (AP) is characterized by elevated intracellular Ca2+ concentrations, mitochondrial dysfunction, and oxidative stress in pancreatic acinar cells. Algal oil (AO) has demonstrated antioxidant and anti-inflammatory properties. This study aims to explore the effects of algal oil on the microenvironment of AP. Rat pancreatic acinar AR42J cells were pretreated with AO containing 0, 50, 100, or 150 μM of docosahexaenoic acid (DHA) 2 h prior to AP induction using sodium taurocholate (STC). After 1 h of STC treatment, AR42J cells exhibited a significant increase in intracellular Ca2+ concentration and the production of amylase, lipase, reactive oxygen species, and pro-inflammatory mediators, including tumor necrosis factor-α and interleukin-6. These STC-induced increases were markedly reduced in cells pretreated with AO. In comparison to cells without AO, those treated with a high dose of AO before STC exposure demonstrated a significant increase in mitochondrial membrane potential and a decrease in lipid peroxidation. Furthermore, STC-activated nuclear factor kappa-B (NF-κB) was attenuated in AO-pretreated cells, as evidenced by a significant decrease in activated NF-κB. In conclusion, AO may prevent damage to pancreatic acinar cells by alleviating intracellular Ca2+ overload, mitigating mitochondrial dysfunction, reducing oxidative stress, and attenuating NF-κB-targeted inflammation.

Functional role of IL-19 in a mouse model of L-arginine-induced pancreatitis and related lung injury

IL-19 is a member of IL-10 family and is mainly produced by macrophages. Acute pancreatitis (AP) is an inflammatory disease characterized by acinar cell injury and necrosis. In the present study, the role of IL-19 in AP and AP-associated lung injury in mice was explored using L-arginine-induced pancreatitis. Experimental pancreatitis was induced by intraperitoneal injection of L-arginine in wild-type (WT) and IL-19 gene-deficient (IL-19 KO) mice. Among the mice treated with L-arginine, the serum amylase level was significantly increased in the IL-19 KO mice, and interstitial edema, analyzed using hematoxylin and eosin-stained sections, was aggravated mildly in IL-19 KO mice compared with WT mice. Furthermore, the mRNA expression of tumor necrosis factor-α was significantly upregulated in IL-19 KO mice treated with L-arginine compared with WT mice treated with L-arginine. IL-19 mRNA was equally expressed in the pancreases of both control and L-arginine-treated WT mice. The conditions of lung alveoli were then evaluated in WT and IL-19 KO mice treated with L-arginine. In mice with L-arginine-induced pancreatitis, the alveolar area was remarkedly decreased, and expression of lung myeloperoxidase was significantly increased in IL-19 KO mice compared with WT mice. In the lungs, the mRNA expression of IL-6 and inducible nitric oxide synthase was significantly increased in IL-19 KO mice compared with WT mice. In summary, IL-19 was proposed to alleviate L-arginine-induced pancreatitis by regulating TNF-α production and to protect against AP-related lung injury by inhibiting neutrophil migration.

Elevated Serum Triglyceride Levels in Acute Pancreatitis: A Parameter to be Measured and Considered Early

Background

The value of serum triglycerides (TGs) related to complications and the severity of acute pancreatitis (AP) has not been clearly defined. Our study aimed to analyze the association of elevated levels of TG with complications and the severity of AP.

Methods

The demographic and clinical data of patients with AP were prospectively analyzed. TG levels were measured in the first 24 h of admission. Patients were divided into two groups: one with TG values of<200 mg/dL and another with TG≥200 mg/dL. Data on the outcomes of AP were collected.

Results

From January 2016 to December 2019, 247 cases were included: 200 with TG<200 mg/dL and 47 with TG≥200 mg/dL. Triglyceride levels≥200 mg/dL were associated with respiratory failure (21.3 vs. 10%, p=0.033), renal failure (23.4 vs. 12%, p=0.044), cardiovascular failure (19.1 vs. 7.5%, p=0.025), organ failure (34 vs. 18.5%, p=0.02), persistent organ failure (27.7 vs. 9.5%, p=0.001), multiple organ failure (19.1 vs. 8%, p=0.031), moderately severe and severe AP (68.1 vs. 40.5%, p=0.001), pancreatic necrosis (63.8 vs. 34%, p<0.001), and admission to the intensive care unit (27.7 vs. 9.5%, p=0.003). In the multivariable analysis, a TG level of≥200 mg/dL was independently associated with respiratory, renal, and cardiovascular failure, organ failure, persistent organ failure, multiple organ failure, pancreatic necrosis, severe pancreatitis, and admission to the intensive care unit (p<0.05).

Conclusions

In our cohort, TG≥200 mg/dL was related to local and systemic complications. Early determinations of TG levels in AP could help identify patients at risk of complications.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00268-022-06533-w.

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.

Protectin D1 decreases pancreatitis severity in mice by inhibiting neutrophil extracellular trap formation

BACKGROUND

Docosahexaenoic acid-derived protectin D1 (PD1) was identified critical in the resolution of inflammation in vivo, where it modulates the innate immune response and stimulates resolution. Acute pancreatitis (AP) is characterized by local pancreatic inflammation with mild forms whereas systemic inflammation with severe forms. Herein we investigate the impact of PD1 in murine models of pancreatitis.

METHODS

Three independent AP models, which induced in male mice via intraperitoneal injection of caerulein, L-arginine or pancreatic duct ligation, were used to confirm the protective effect of PD1. Infiltrationsof neutrophils and macrophages in pancreas were detected by flow cytometry and immunohistochemistry. In vitro and in vivo neutrophil extracellular traps formation was detected by immunofluorescence staining. Expression of peptidylarginine deiminase 4 (PAD4) in activated neutrophils was evaluated by western blotting.

RESULTS

Systemic treatment with PD1 reduced serum activities of amylase and lipase, blunted the concentrations of tumor necrosis factor-α and interleukin-6 in serum and protected against pancreas histologic damage in three AP models. PD1 also prolonged the survival in the pancreatic duct ligation model. Moreover, pancreatic infiltrationofneutrophils and neutrophil CitH3 expression were reduced after PD1 administration. In vitro studies revealed PD1 decreased supernatant cell-free DNA and CitH3 levels and downregulated PAD4 expression in mouse bone-marrow derived neutrophils. However, in the caerulein mice pretreated with GSK484 hydrochloride, an inhibitor of PAD4, PD1 treatment showed no more protective effect.

CONCLUSIONS

PD1 ameliorates AP by decreasing early infiltration of neutrophils into the pancreas and neutrophil extracellular traps formation through PAD4. These results supply the foundation to consider PD1 as a therapy for AP.

Calcium channels blockers toxins attenuate abdominal hyperalgesia and inflammatory response associated with the cerulein-induced acute pancreatitis in rats

Agents that modulate the activity of high-voltage gated calcium channels (HVCCs) exhibit experimentally and clinically significant effect by relieving visceral pain. Among these agents, the toxins Phα1β and ω-conotoxin MVIIA effectively reduce chronic pain in rodent models. The molecular mechanisms underlying the chronic pain associated with acute pancreatitis (AP) are poorly understood. Hypercalcemia is a risk factor; the role of cytosolic calcium is considered to be a modulator of pancreatitis. Blockade of Ca2+ signals may be useful as a prophylactic treatment of pancreatitis. We explored the pathophysiological roles of three peptide toxins: Phα1β and its recombinant form CTK 01512-2-blockers of TRPA1 receptor and HVCCs and ω-conotoxin MVIIA, a specific blocker of N-type calcium channels in cerulein-induced AP. Cerulein injection elicits AP in rats, evidenced by an increase in hyperalgesic pain, inflammatory infiltration, amylase and lipase secretion, and reactive oxygen species, TNF-α, and p65 NF-κB levels. These effects of cerulein-induced AP were abolished by Phα1β and its recombinant form CTK 01512-2, whereas ω-conotoxin MVIIA had no effect on the induced increase in pancreatic enzyme secretion. Our results demonstrate that Phα1β and CTK 01512-2 toxins-antagonists of HVCCs and TRPA1 receptor presented an effective response profile, in the control of nociception and inflammatory process in the AP model in rats, without causing changes in spontaneous locomotion of the rats.

Vinpocetine ameliorates L-arginine induced acute pancreatitis via Sirt1/Nrf2/TNF pathway and inhibition of oxidative stress, inflammation, and apoptosis

OBJECTIVES

Acute pancreatitis (AP) is a common severe critical illness with a high mortality rate. We aimed to study the effect of vinpocetine (Vinpo) in the treatment of AP because of its anti-inflammatory, antioxidant, and antiapoptotic effects.

MATERIALS AND METHODS

Thirty two adult male albino Wistar rats were randomized to four groups: control group, Vinpo group (20 mg/kg.P.O.), l-arginine group (two intraperitoneal injections of l-arginine 2.5 g/kg, 1 h apart), and Vinpo + L-arginine group. Vinpo administration was once daily for 7 consecutive days and started 1 h later after l-arginine administration. We measured serum enzyme biomarkers (lipase and amylase), levels of pancreatic malondialdehyde (MDA), total antioxidant capacity (TAC), reduced glutathione (GSH), total sulfhydryl (T-SH), total nitrite/nitrate (NOx), Interluken-6 (IL-6), tumor necrosis factor-alpha (TNF-α), Nuclear factor (erythroid-derived 2)-like 2 (Nrf2), Sirtuin type 1 (Sirt1), and caspase-3 activity. Furthermore; histological changes, anti-insulin, and inducible nitric oxide synthase (iNOS) immuno-expressions were examined.

RESULTS

l-arginine group displayed AP as manifested by a significant increase in serum lipase and amylase, MDA, NOx, IL-6, TNF-α, caspase-3 with iNOS immuno-expression. Histological changes indicating marked pancreatic injury were observed together with a significant decrease in TAC, GSH, T-SH, Nrf2, Sirt1 levels, and anti-insulin immuno-expression. Vinpo showed a significant amelioration in all parameters.

CONCLUSION

Vinpo possesses potent ameliorative effects against AP by decreasing oxidative stress, inflammatory process, and apoptosis through regulation of the Sirt1/Nrf2/TNF-α pathway.

Drug discovery and formulation development for acute pancreatitis

Acute pancreatitis is a sudden inflammation and only last for a short time, but might lead to a life-threatening emergency. Traditional drug therapy is an essential supportive method for acute pancreatitis treatment, yet, failed to achieve satisfactory therapeutic outcomes. To date, it is still challenging to develop therapeutic medicine to redress the intricate microenvironment promptly in the inflamed pancreas, and more importantly, avoid multi-organ failure. The understanding of the acute pancreatitis, including the causes, mechanism, and severity judgment, could help the scientists bring up more effective intervention and treatment strategies. New formulation approaches have been investigated to precisely deliver therapeutics to inflammatory lesions in the pancreas, and some even could directly attenuate the pancreatic damages. In this review, we will briefly introduce the involved pathogenesis and underlying mechanisms of acute pancreatitis, as well as the traditional Chinese medicine and the new drug option. Most of all, we will summarize the drug delivery strategies to reduce inflammation and potentially prevent the further development of pancreatitis, with an emphasis on the bifunctional nanoparticles that act as both drug delivery carriers and therapeutics.

Effects and mechanism of the etanercept on pancreatic encephalopathy

Pancreatic encephalopathy (PE) is a common fatal complication of acute pancreatitis (AP). Proinflammatory cytokines such as tumor necrosis factor (TNF)‑α and interleukin (IL)‑6 are generated during AP, and act synergistically to promote PE and multisystem failure. Caerulein‑induced AP provides a convenient model to explore the role of proinflammatory cytokines in PE. The aim of the present study was to examine the effect of the TNF‑α inhibitor etanercept in PE models and elucidate the regulatory mechanisms. To model PE in vitro, rat hippocampal H19‑7/IGF‑IR neuronal cells were treated with 10 nmol/ml caerulein alone or in combination with etanercept (1, 10 or 100 µmol/ml). To model PE in vivo, rats were injected with 50 µg/kg caerulein alone or combined with 10 mg/kg etanercept. At 6 h after administration, it was noted that etanercept downregulated expression of TNF‑α, IL‑1β and IL‑6 by negatively regulating NF‑κB (a master regulator of cytokine expression) signaling, and prevented the accumulation of reactive oxygen species. Conversely, etanercept promoted the expression of the neurotrophic and anti‑inflammatory hypoxia‑inducible factor 1 α (HIF‑1α). In rat hippocampus, etanercept also reduced the levels of TNF‑α, IL‑1β and IL‑6, upregulated HIF‑1α expression and inhibited the inflammatory response to reduce edema and neural necrosis. Together, these data suggested that etanercept could attenuate caerulein‑induced PE, at least in part via suppression of NF‑κB signaling and alleviation of oxidative stress.

Docosahexaenoic acid inhibits zymogen activation by suppressing vacuolar ATPase activation in cerulein-stimulated pancreatic acinar cells

BACKGROUND

The premature activation of digestive enzyme zymogens within pancreatic acinar cells is an important early feature of acute pancreatitis. Supraphysiological concentrations of cholecystokinin (CCK) cause intrapancreatic zymogen activation and acute pancreatitis. Stimulation of vacuolar ATPase (vATPase) activity is required for zymogen activation in pancreatic acinar cells. Parkin, a multiprotein E3 ubiquitin ligase complex, promotes vATPase ubiquitination and degradation, which inhibits vATPase activity. Docosahexaenoic acid (DHA), an omega-3 fatty acid, exerts anti-inflammatory effects. It is reported to bind to G-protein coupled receptor 120 (GPR120) and GPR40. DHA induces the degradation of certain proteins by activating ubiquitin-proteasome system in various cells. This study aimed to investigate whether DHA induces Parkin and inhibits vATPase activity, resulting in zymogen inactivation in pancreatic acinar AR42J cells stimulated with cerulein, a CCK analog.

RESULTS

Cerulein induced the translocation of the cytosolic V1 domain (E subunit) of vATPase to the membrane, which indicated vATPase activation, and zymogen activation in AR42J cells. DHA suppressed the association of the vATPase with membranes, and zymogen activation (increased trypsin activity and amylase release) induced by cerulein. Pretreatment with a GPR120 antagonist AH-7614, a GPR40 antagonist DC260126, or an ubiquitination inhibitor PYR-41 reduced the effect of DHA on cerulein-induced zymogen activation. Treatment with PYR-41 reversed the DHA-induced decrease in vATPase activation in cerulein-treated cells. Furthermore, DHA increased the level of Parkin in membranes of cerulein-treated cells.

CONCLUSIONS

DHA upregulates Parkin which inhibits vATPase-mediated zymogen activation, via GPR120 and GPR40, in cerulein-stimulated pancreatic acinar cells.

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

Background

Chronic pancreatitis (CP) is an irreversible progressive disease that destroys exocrine parenchyma, which are replaced by fibrous tissue. As pancreatic fibrosis is a key feature of CP, reducing fibrotic protein content in the pancreas is crucial for preventing CP. Studies suggest that NF-κB facilitates the expression of fibrotic mediators in pancreas and protein kinase C-δ (PKC-δ) regulates NF-κB activation in stimulated pancreatic acinar cells. Docosahexaenoic acid (DHA) is an omega-3 fatty acid having anti-inflammatory and anti-fibrotic effects. It has been shown to inhibit NF-κB activity in cerulein-stimulated pancreatic acinar cells which is a cellular model of CP. In the present study, we investigated if DHA inhibits expression of fibrotic mediators by reducing PKC-δ and NF-κB expression in mouse pancreatic tissues with CP.

Methods

For six weeks, mice were weekly induced for acute pancreatitis to develop CP. Furthermore, acute pancreatitis was induced by hourly intraperitoneal injections of cerulein (50 μg/kg × 7). Mice were administered DHA (10 μM) via drinking water before and after CP induction.

Results

Cerulein-induced pancreatic damages like decreased pancreatic weight/total body weight, leukocyte infiltration, necrosis of acinar cells, and vacuolization were found to be inhibited by DHA. Additionally, DHA inhibited cerulein-induced fibrotic mediators like alpha-smooth muscle actin and fibronectin in pancreas. DHA reduced expression of PKC-δ and NF-κB p65 in pancreatic tissues of cerulein-treated mice.

Conclusions

DHA may be beneficial in preventing CP by suppressing pancreatic expression of fibrotic mediators.

Pim-3 alleviates lipopolysaccharide-stimulated AR42J pancreatic acinar cell injury via improving the inflammatory microenvironment

Acute pancreatitis (AP) is a common acute abdominal disease characterized by pancreatic aseptic inflammation, with ~20% of patients progressing to severe AP (SAP) with a high mortality rate. The aim of this study was to explore the protective effects of Pim-3 proto-oncogene, serine/threonine kinase (Pim-3) on rat pancreatic acinar AR4-2J cells damaged by lipopolysaccharide (LPS). The recombinant plasmid p-enhanced green fluorescent protein (pEGFP)-N2/Pim-3 was transiently transfected into AR42J cells and the AR42J cells were then treated with 2 µg/ml LPS. Subsequently, the proliferation of AR42J cells was detected using MTT assay. The cell cycle progression and apoptosis rate of the AR42J cells were examined using flow cytometry. AR42J cell migration was assessed using wound healing assays. Additionally, RT-semi quantitative PCR and western blot analyses were used to detect the mRNA and protein expression levels, respectively, of Pim-3, interleukin (IL)-6, IL-1β, tumor necrosis factor (TNF)-α, intercellular adhesion molecule (ICAM)-1 and Occludin in AR42J cells. The results revealed that proliferation of AR42J cells was significantly enhanced and cell apoptosis was markedly reduced in the pEGFP-N2/Pim-3 + LPS group. The proportion of AR42J cells in G1 phase in the pEGFP-N2/Pim-3 + LPS group was decreased, whereas the proportion of cells in the G2 and S phases was increased. The wound healing assays demonstrated that AR42J cell migration was significantly increased in the pEGFP-N2/Pim-3 + LPS group. Finally, the expression levels of IL-6, IL-1β, TNF-α and ICAM-1 were significantly decreased in the pEGFP-N2/Pim-3 + LPS group, whereas the expression of Occludin was significantly increased. The present study demonstrated that raised expression levels of Pim-3 can protect AR42J cells from LPS-induced injury by modifying the inflammatory microenvironment, suggesting that Pim-3 may be a potential target for AP or SAP therapy.

Influence of omega-3 fatty acid on orthodontic tooth movement in rats: A biochemical, histological, immunohistochemical and gene expression study

OBJECTIVE

The aim of this study was to investigate the effects of omega-3 fatty acids on orthodontic tooth movement.

SETTING AND SAMPLE POPULATION

For this study, 56 12-week-old adult male Wistar albino rats from the Animal Laboratory at Adnan Menderes University, Faculty of Medicine, were used.

MATERIAL AND METHODS

Rats were randomly divided into seven groups (n = 8 each): control group (without any treatment), tooth movement groups (three groups of animals with only tooth movement) and omega groups (three groups of animals with tooth movement and omega-3 administration). Omega-3 fatty acids were administered to the rats systemically during the tooth movement period. On the 3rd, 7th and 14th days after the orthodontic tooth movement, the rats were sacrificed and biochemical, histological, immunohistochemical andgene expression examinations were performed.

RESULTS

On the 14th experimental day, the amount of tooth movement in the omega groups was significantly lower than the tooth movement groups (P = 0.012). Biochemical experimentsshowed that the omega groups had significantly lower total oxidant levels and higher total antioxidant levels compared to the tooth movement group on the 14th experimental day (P = 0.001). The levels of RANKL, IL-6 and IL-1β in the omega groups were significantly lower than the tooth movement groups on all experimental days (P < 0.05).

CONCLUSION

Systemic administration of omega-3 fatty acids showed antioxidant and antiinflammatory effects and decelerate the orthodontic tooth movement.

A Mini-Review on the Effect of Docosahexaenoic Acid (DHA) on Cerulein-Induced and Hypertriglyceridemic Acute Pancreatitis

Acute pancreatitis refers to the sudden inflammation of the pancreas. It is associated with premature activation and release of digestive enzymes into the pancreatic interstitium and systemic circulation, resulting in pancreatic tissue autodigestion and multiple organ dysfunction, as well as with increased cytokine production, ultimately leading to deleterious local and systemic effects. Although mechanisms involved in pathogenesis of acute pancreatitis have not been completely elucidated, oxidative stress is regarded as a major risk factor. In human acute pancreatitis, lipid peroxide levels in pancreatic tissues increase. Docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid (C22:6n-3), exerts anti-inflammatory and antioxidant effects on various cells. Previous studies have shown that DHA activates peroxisome proliferator-activated receptor-γ and induces catalase, which inhibits oxidative stress-mediated inflammatory signaling required for cytokine expression in experimental acute pancreatitis using cerulein. Cerulein, a cholecystokinin analog, induces intra-acinar activation of trypsinogen in the pancreas, which results in human acute pancreatitis-like symptoms. Therefore, DHA supplementation may be beneficial for preventing or inhibiting acute pancreatitis development. Since DHA reduces serum triglyceride levels, addition of DHA to lipid-lowering drugs like statins has been investigated to reduce hypertriglyceridemic acute pancreatitis. However, high DHA concentrations increase cytosolic Ca²⁺, which activates protein kinase C and may induce hyperlipidemic acute pancreatitis. In this review, effect of DHA on cerulein-induced and hypertriglyceridemic acute pancreatitis has been discussed. The relation of high concentration of DHA to hyperlipidemic acute pancreatitis has been included.