Jiandong Ren

Hydrogen-Rich Saline Inhibits NLRP3 Inflammasome Activation and Attenuates Experimental Acute Pancreatitis in Mice

Increasing evidence has demonstrated that reactive oxygen species (ROS) induces oxidative stress and plays a crucial role in the pathogenesis of acute pancreatitis (AP). Hydrogen-rich saline (HRS), a well-known ROS scavenger, has been shown to possess therapeutic benefit on AP in many animal experiments. Recent findings have indicated that the NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome, an intracellular multiprotein complex required for the maturation of interleukin- (IL-) 1β, may probably be a potential target of HRS in the treatment of AP. Therefore, in this study, we evaluated the activation of NLRP3 inflammasome and meanwhile assessed the degree of oxidative stress and inflammatory cascades, as well as the histological alterations in mice suffering from cerulein-induced AP after the treatment of HRS. The results showed that the activation of NLRP3 inflammasome in AP mice was substantially inhibited following the administration of HRS, which was paralleled with the decreased NF-κB activity and cytokines production, attenuated oxidative stress and the amelioration of pancreatic tissue damage. In conclusion, our study has, for the first time, revealed that inhibition of the activation of NLRP3 inflammasome probably contributed to the therapeutic potential of HRS in AP.

Effects of treatment with hydrogen sulfide on methionine-choline deficient diet-induced non-alcoholic steatohepatitis in rats

Oxidative stress and inflammation play important roles in the progression from simple fatty liver to non‐alcoholic steatohepatitis (NASH). The aim of this work was to investigate whether treatment with hydrogen sulfide (H2S) prevented NASH in rats through abating oxidative stress and suppressing inflammation.

Hydrogen-rich saline reduces the oxidative stress and relieves the severity of trauma-induced acute pancreatitis in rats.

BACKGROUND Currently, little evidence exists to support whether the therapeutic approaches for treating ordinary acute pancreatitis (AP) are effective in trauma-induced pancreatitis. Hydrogen-rich (H2) saline is an antioxidant treatment capable of ameliorating the severity of L-arginine-induced AP. In this study, we attempted to validate its protective role against traumatic pancreatitis (TP). METHODS A previously established experimental rat model of TP was generated by controlled delivery of high pressure air impact. The protective effects of H2 saline against TP were evaluated in this model system by measuring survival rate and determining changes in histopathology, plasma enzymes, cytokines, and oxidative stress-associated molecules. RESULTS Intraperitoneal administration of H2-rich saline produced a pronounced protection against TP in rats. Significant improvements were observed in survival rate and histopathological findings. In addition, plasma cytokines concentrations were reduced in H2 saline-treated TP rats. Although no marked inhibitory effect on plasma amylase and lipase activities was observed, H2 saline caused considerable suppression of pancreatic malondialdehyde level and recruitment of endogenous pancreatic antioxidants, such as glutathione and superoxide dismutase. CONCLUSIONS H2-rich saline has beneficial effects on TP, presumably because of its detoxification activities against excessive reactive oxygen species. Our findings highlight the potential of H2-rich saline as a therapeutic agent of trauma-induced AP.

A synthetic cyclic peptide derived from Limulus anti-lipopolysaccharide factor neutralizes endotoxin in vitro and in vivo

Endotoxin, also known as lipopolysaccharide (LPS), is the major mediator of septic shock due to Gram-negative bacterial infections. Recently, much attention has been focused on cationic peptides which possess the potential to detoxify LPS. Limulus anti-LPS factor (LALF), a protein found in the horseshoe crab (Limulus polyphemus), has been proved with striking anti-LPS effects. We synthesized a cyclic peptide (CLP-19), and then investigated its bioactivity both in vitro and in vivo. The ability of CLP-19 to neutralize LPS in vitro was tested using a Limulus amebocyte lysate (LAL) assay and the LPS-binding affinity was measured with an affinity biosensor method. The synthetic peptide LALF31-52 (residues 31 to 52 of LALF) was used as the positive control peptide in this study. It was found that CLP-19 exhibited the significant activity to antagonize LPS without observable cytotoxicity effect on mouse macrophages. CLP-19 directly bound to LPS, and neutralized it in a dose-dependent manner in the LAL assay. Moreover, CLP-19 also showed the remarkable ability to protect mice from lethal LPS attack and to inhibit the LPS-induced tumor necrosis factor alpha (TNF-alpha) release by decreasing serum LPS in vivo. Our work suggests that this peptide is worthy of further investigation as a potential anti-LPS agent in the treatment of septic shock.

Lipopolysaccharide (LPS) detoxification of analogue peptides derived from limulus anti-LPS factor.

Lipopolysaccharide (LPS) plays a critical role in the pathogenesis of sepsis due to gram-negative bacterial infections. Therefore, LPS-neutralizing molecules could have important clinical applications. Our previous work showed, CLP19, an analogue peptide derived from limulus anti-LPS factor (LALF), possessed the capacity to neutralize LPS and thereby inhibit the LPS-induced responses. However, potential cytotoxicity of CLP19 was also found, especially when added to human red blood cells. Accordingly we further developed two peptides (designated as CLP19-1 and CLP19-2) by single- and double-point amino acid substitution of CLP19, respectively, in order to reduce its toxicity and meanwhile retain the anti-LPS activity. In this study, the LPS-detoxifying effectiveness of these peptides was evaluated both in vitro and in vivo. CLP19-1 was found to dose-dependently neutralize LPS in vitro, with significantly lower hemolysis of red blood cells as compared with CLP19. Further in vivo tests verified that CLP19-1 exerted significant protective effects on mice against LPS, characterized by significantly improved survival, decreasing of tumor necrosis factor alpha (TNF-α) serum level and alleviation of tissue injury. Our work indicates that CLP19-1 is worthy of further study as potential anti-LPS agents for the management of sepsis.

Mangiferin attenuates blast-induced traumatic brain injury via inhibiting NLRP3 inflammasome.

There is growing evidence that Mangiferin possess therapeutic benefit during neuroinflammation on various brain injury models due to its anti-inflammatory properties. It is reported that inflammatory plays a crucial role in the pathogenesis of secondary injury induced by the blast-induced traumatic brain injury (bTBI). However, the role of mangiferin in bTBI is yet to be studied. In our study, the potential effect of mangiferin in the duration of bTBI was examined first. Fortunately, the amelioration of cerebral cortex damage was found in rats suffering bTBI after mangiferin administration. Furthermore, the detail mechanism of mangiferins beneficial actions in bTBI was also studied. The results revealed that mangiferin might alleviate brain damage in rats with bTBI by inhibiting the NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome activation, which was accompanied by mangiferins inhibition of oxidative stress and pro-inflammatory cytokines production. Therefore, this research allows us to speculate that, for first time, NLRP3 is involved in the anti-inflammatory effect of mangiferin in the cerebral cortex, and mangiferin could be a potential therapy drug for bTBI.

Glycyrrhizin Suppresses the Expressions of HMGB1 and Relieves the Severity of Traumatic Pancreatitis in Rats

Background High mobility group box 1 (HMGB1) plays important roles in a large variety of diseases; glycyrrhizin (GL) is recognized as an HMGB1 inhibitor. However, few studies have focused on whether glycyrrhizin can potentially improve the outcome of traumatic pancreatitis (TP) by inhibiting HMGB1. Methods A total of 60 male Wistar rats were randomly divided into three groups (n = 20 in each): Control group, TP group and TP-GL group. Pancreatic trauma was established with a custom-made biological impact machine-III, and GL was administered at 15 minutes after the accomplishment of operation. To determine survival rates during the first 7 days after injury, another 60 rats (n = 20 in each) were grouped and treated as mentioned above. At 24 hours of induction of TP, the histopathological changes in pancreas were evaluated and serum amylase levels were tested. Serum tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and HMGB1 were measured using enzyme linked immunosorbent assay. HMGB1 expressions in pancreas were measured using immunohistochemical staining, Western blot and Real-Time PCR analysis. Results Serum levels of HMGB1, TNF-α and IL-6 were increased dramatically in TP group at 24 hours after induction of TP. However, these indicators were reduced significantly by GL administration in TP-GL group comparing with TP group (P<0.05). Meanwhile, survival analysis showed that the seven-day survival rate in TP-GL group was significantly higher than that in TP group (85% versus 65%, P<0.05). GL treatment significantly decreased the pancreatic protein and mRNA expressions of HMGB1 and ameliorated the pancreatic injury in rats with TP. Conclusions Glycyrrhizin might play an important role in improving survival rates and ameliorating pancreatic injury of TP by suppression of the expressions of HMGB1 and other proinflammatory cytokine.

Pharmacological blockade of the MaxiK channel attenuates experimental acute pancreatitis and associated lung injury in rats.

Increasing evidence has recently demonstrated that soluble heparan sulfate (HS), a degradation product of extracellular matrix produced by elastase, plays a key role in the aggravation of acute pancreatitis (AP) and associated lung injury. However little is known about the detailed mechanism underlying HS-induced inflammatory cascade. Our previous work has provided a valuable clue that a large-conductance K(+) channel (MaxiK) was involved in the HS-stimulated activation of murine macrophages. Here we attempted to ask whether pharmacological inhibition of the MaxiK channel will exert beneficial effects on the treatment of AP and secondary lung injury. The protective effects of paxilline, a specific blocker of MaxiK, on rats against sodium taurocholate induced AP were evaluated. Our data showed that paxilline substantially attenuated AP and resultant lung injury, mainly by limiting the burst of inflammatory responses, as proven by decreased plasma concentrations of tumor necrosis factor-α and macrophage inflammatory protein-2, together with unimpaired pancreatic enzyme activities in rats suffering from AP. Compared with the therapeutic administration, pre-treatment of paxilline showed superior potential to slow down the progress of AP. Furthermore, AP rats received paxilline exhibited improved histopathologic alterations both in the pancreas and the lungs, and even lower lung MPO activity. Taken together, our study provides evidence that MaxiK is involved in the spread of inflammatory responses and the following lung injury during the attack of AP, indicating that this ion channel is a promising candidate as a therapeutic target for AP.

Involvement of a membrane potassium channel in heparan sulphate-induced activation of macrophages

Increasing evidence has demonstrated that Toll‐like receptor 4 (TLR4) ‐mediated systemic inflammatory response syndrome accompanied by multiple organ failure, is one of the most common causes of death in patients with severe acute pancreatitis. Recent reports have revealed that heparan sulphate (HS) proteoglycan, a component of extracellular matrices, potentiates the activation of intracellular pro‐inflammatory responses via TLR4, contributing to the aggravation of acute pancreatitis. However, little is known about the participants in the HS/TLR4‐mediated inflammatory cascades. Our previous work provided a clue that a membrane potassium channel (MaxiK) is responsible for HS‐induced production of inflammatory cytokines. Therefore, in this report we attempted to reveal the roles of MaxiK in the activation of macrophages stimulated by HS. Our results showed that incubation of RAW264.7 cells with HS up‐regulated MaxiK and TLR4 expression levels. HS could also activate MaxiK channels to promote the efflux of potassium ions from cells, as measured by the elevated activity of caspase‐1, whereas this was significantly abolished by treatment with paxilline, a specific blocker of the MaxiK channel. Moreover, it was found that paxilline substantially inhibited HS‐induced activation of several different transcription factors in macrophages, including nuclear factor‐κB, p38 and interferon regulatory factor‐3, followed by decreased production of tumour necrosis factor‐α and interferon‐β. Taken together, our investigation provides evidence that the HS/TLR4‐mediated intracellular inflammatory cascade depends on the activation of MaxiK, which may offer an important opportunity for a new approach in therapeutic strategies of severe acute pancreatitis.

Management of patients with sphincter of Oddi dysfunction based on a new classification.

AIM To propose a new classification system for sphincter of Oddi dysfunction (SOD) based on clinical data of patients. METHODS The clinical data of 305 SOD patients documented over the past decade at our center were analyzed retrospectively, and typical cases were reported. RESULTS The new classification with two more types (double-duct, biliary-pancreatic reflux) were set up on the basis of the Milwaukee criteria. There were 229 cases of biliary-type SOD, including 192 (83.8%) cases cured endoscopically, and 29 (12.7%) cured by open abdominal surgery, and the remaining 8 (3.5%) cases observed with unstable outcomes. Eight (50%) patients with pancreatic-type SOD were cured by endoscopic treatment, and the remaining 8 patients were cured after open abdominal surgery. There were 19 cases of double-duct-type SOD, which consisted of 7 (36.8%) patients who were cured endoscopically and 12 (63.2%) who were cured surgically. A total of 41 cases were diagnosed as biliary-pancreatic-reflux-type SOD. Twenty (48.8%) of them were treated endoscopically, 16 (39.0%) were treated by open abdominal surgery, and 5 (12.2%) were under observation. CONCLUSION The newly proposed SOD classification system introduced in this study better explains the clinical symptoms of SOD from the anatomical perspective and can guide clinical treatment of this disease.