Ulinastatin preconditioning attenuates inflammatory reaction of hepatic ischemia reperfusion injury in rats via high mobility group box 1(HMGB1) inhibition

The significant mechanism and treatments of cell death in heatstroke

With global warming, extreme environmental heat is becoming a social issue of concern, which can cause adverse health results including heatstroke (HS). Severe heat stress is characterized by cell death of direct heat damage, excessive inflammatory responses, and coagulation disorders that can lead to multiple organ dysfunction (MODS) and even death. However, the significant pathophysiological mechanism and treatment of HS are still not fully clear. Various modes of cell death, including apoptosis, pyroptosis, ferroptosis, necroptosis and PANoptosis are involved in MODS induced by heatstroke. In this review, we summarized molecular mechanism, key transcriptional regulation as for HSF1, NRF2, NF-κB and PARP-1, and potential therapies of cell death resulting in CNS, liver, intestine, reproductive system and kidney injury induced by heat stress. Understanding the mechanism of cell death provides new targets to protect multi-organ function in HS.

Hepatoprotective Effects of Glycyrrhetinic Acid on Lithocholic Acid-Induced Cholestatic Liver Injury Through Choleretic and Anti-Inflammatory Mechanisms

Cholestasis is a clinical syndrome triggered by the accumulation and aggregation of bile acids by subsequent inflammatory responses. The present study investigated the protective effect of glycyrrhetinic acid (GA) on the cholestatic liver injury induced by lithocholic acid (LCA) from both anti-inflammatory and choleretic mechanistic standpoints. Male C57BL/6 mice were treated with LCA twice daily for 4 days to induce intrahepatic cholestasis. GA (50 mg/kg) and pregnenolone 16α-carbonitrile (PCN, 45 mg/kg) were intraperitoneally injected 3 days before and throughout the administration of LCA, respectively. Plasma biochemical indexes were determined by assay kits, and hepatic bile acids were quantified by LC-MS/MS. Hematoxylin and eosin staining of liver sections was performed for pathological examination. Protein expression of the TLRs/NF-κB pathway and the mRNA levels of inflammatory cytokines and chemokines were examined by Western blotting and PCR, respectively. Finally, the hepatic expression of pregnane X receptor (PXR) and farnesoid X receptor (FXR) and their target genes encoding metabolic enzymes and transporters was evaluated. GA significantly reversed liver necrosis and decreased plasma ALT and ALP activity. Plasma total bile acids, total bilirubin, and hepatic bile acids were also remarkably preserved. More importantly, the recruitment of inflammatory cells to hepatic sinusoids was alleviated. Additionally, the protein expression of TLR2, TLR4, and p-NF-κBp65 and the mRNA expression of CCL2, CXCL2, IL-1β, IL-6, and TNF-α were significantly decreased. Moreover, GA significantly increased the expression of hepatic FXR and its target genes, including BSEP, MRP3, and MRP4. In conclusion, GA protects against LCA-induced cholestatic liver injury by inhibiting the TLR2/NF-κB pathway and upregulating hepatic FXR expression.

High-mobility group box-1 and inter-alpha inhibitor proteins: In vitro binding and co-localization in cerebral cortex after hypoxic-ischemic injury

The high-mobility group box-1 (HMGB1) protein is a transcription-regulating protein located in the nucleus. However, it serves as a damage-associated molecular pattern protein that activates immune cells and stimulates inflammatory cytokines to accentuate neuroinflammation after release from damaged cells. In contrast, Inter-alpha Inhibitor Proteins (IAIPs) are proteins with immunomodulatory effects including inhibition of pro-inflammatory cytokines. We have demonstrated that IAIPs exhibit neuroprotective properties in neonatal rats exposed to hypoxic-ischemic (HI) brain injury. In addition, previous studies have suggested that the light chain of IAIPs, bikunin, may exert its anti-inflammatory effects by inhibiting HMGB1 in a variety of different injury models in adult subjects. The objectives of the current study were to confirm whether HMGB1 is a target of IAIPs by investigating the potential binding characteristics of HMGB1 and IAIPs in vitro, and co-localization in vivo in cerebral cortices after exposure to HI injury. Solid-phase binding assays and surface plasmon resonance (SPR) were used to determine the physical binding characteristics between IAIPs and HMGB1. Cellular localizations of IAIPs-HMGB1 in neonatal rat cortex were visualized by double labeling with anti-IAIPs and anti-HMGB1 antibodies. Solid-phase binding and SPR demonstrated specific binding between IAIPs and HMGB1 in vitro. Cortical cytoplasmic and nuclear co-localization of IAIPs and HMGB1 were detected by immunofluorescent staining in control and rats immediately and 3 hours after HI. In conclusion, HMGB1 and IAIPs exhibit direct binding in vitro and co-localization in vivo in neonatal rats exposed to HI brain injury suggesting HMGB1 could be a target of IAIPs.

Kaempferol from Penthorum chinense Pursh suppresses HMGB1/TLR4/NF-κB signaling and NLRP3 inflammasome activation in acetaminophen-induced hepatotoxicity

Acetaminophen (APAP) is one of the safest and most effective over-the-counter (OTC) analgesics and antipyretics, but excessive doses of APAP will induce hepatotoxicity with high morbidity and mortality worldwide. Kaempferol (KA), a flavonoid compound derived from the medicinal and edible plant of Penthorum chinense Pursh, has been reported to exert a profound anti-inflammatory and antioxidant activity. In this study, we explored the protective effect and novel mechanism of KA against APAP-induced hepatotoxicity. The results revealed that KA pretreatment significantly reduced the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), relieved hepatocellular damage and apoptosis, attenuated the exhaustion of glutathione (GSH) and accumulation of malondialdehyde (MDA), increased the expression of antioxidative enzymes (e.g., heme oxygenase 1 (HO-1) and NADPH quinone oxidoreductase 1 (NQO1)), and thus restrained APAP-induced oxidative damage in the liver. KA suppressed the expression of NLRP3 and reduced the levels of pro-inflammatory factors, including interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). Moreover, KA remarkably inhibited high-mobility group box 1 (HMGB1) and toll-like receptor 4 (TLR4) expression as well as nuclear factor kappa-B (NF-κB) activation for liver protection against APAP-induced inflammatory responses and apoptosis. Taken together, our findings suggested that KA could effectively protect hepatocytes from APAP hepatotoxicity through the up-regulation of HO-1 and NQO1 expression, the down-regulation of NLRP3 expression, and the inhibition of the HMGB1/TLR4/NF-κB signaling pathway.

Research progress of ulinastatin in the treatment of liver diseases

Ulinastatin (UTI) is a trypsin inhibitor observed in urine. UTI can treat some diseases by inhibiting the broad-spectrum hydrolysis activity of various enzymes and other pharmacological effects. UTI can widely treat pancreatitis, systemic multiple organ dysfunction syndrome, circulatory failure, and toxic shock clinically. The liver is a major metabolic organ of the human body. Various biological metabolic reactions require the liver's participation. When various physical and chemical factors drive the body, it will damage the liver to varying degrees. As a clinically effective drug, UTI is also known to treat some liver diseases. This article mainly describes UTI's research progress in treating septic liver injury, hepatitis, liver fibrosis, autoimmune liver disease with liver failure, and liver ischemia-reperfusion injury.

Protective effect of ulinastatin on hepatic ischemia reperfusion injury through autophagy activation in Chang liver cells

This study aimed to investigate the protective effect of ulinastatin in hepatic ischemia-reperfusion progress, involving its association with the role of autophagy during hypoxia-induced hypoxia-reoxygenation injury in vitro. The model of hepatic hypoxia/reoxygenation (H/R) injury in Chang liver cells was established. After treatment with ulinastatin at the doses of 10, 100, and 1000 U/mL in H/R liver cells, the cell proliferation was significantly increased, morphological damage was reduced, and the cell apoptosis rate was decreased. The protein levels of antiapoptotic myeloid cell leukemia-1 (Mcl-1) and caspase-3 were upregulated, and C-PARP protein was downregulated. Meanwhile, ulinastatin led to an increase in the messenger RNA and protein levels of autophagy maker Unc-like kinase 1 (ULK1), Beclin-1, and microtubule-associated protein 1 light chain 3 (LC-3) and a decrease in p62. Then, 3-methyladenine (3-MA), an inhibitor of autophagy, made morphological damage and cell apoptosis worsen in ulinastatin-treated H/R liver cells. And the expression levels of caspase-3, C-PARP, p62, Beclin-1, and LC-3, proteins were also reversed by 3-MA. Taken together, our results demonstrate that ulinastatin inhibited the hepatic H/R injury in Chang liver cells, which was, to some extent, related to the autophagy activation.

Ulinastatin protects the lungs of COPD rats through the HMGB1/TLR4 signaling pathway

The present study aimed to investigate the protective mechanism of ulinastatin against lung injury. Rat models with chronic obstructive pulmonary disease (COPD) were used to provide guidance for the medical treatment of this disease. The rats were divided into three groups: A control group, a model group and an experimental group (each, n=10). With the exception of the control group, all of the rats were prepared as models of COPD, using the composite molding method of smoking and intratracheal instillation of lipopolysaccharide. The rats in the model group all received a conventional treatment, while the rats in the experimental group received ulinastatin. A small animal lung function detector was used to examine lung function. The forced expiratory volume/sec (FEV) was negatively correlated with the protein expression levels of Toll-like receptor 4 (TLR4) and high mobility group box protein 1 (HMGB1). Real-time fluorescence quantitative polymerase chain reaction and western blot analyses were used to detect TLR4, MyD88 (myeloid differentiation factor 88), TRAF-6 (TNF receptor-associated factor 6), LOX-1 (lectin-type oxidized LDL receptor 1) and HMGB1 mRNA, along with their protein expression levels. The lung function of rats in the model group was significantly decreased compared with in the control group (P<0.05). In the experimental group the lung function was significantly greater, when compared with in the model group; however, it remained lower than in the control group. The mRNA and protein expression levels of TLR4, MyD88, TRAF-6, LOX-1 and HMGB1 were significantly higher in the model group than in the control and experimental groups; however, levels in the experimental group were significantly higher when compared with in the control group (P<0.05). The TLR4 and HMGB1 expression levels were positively correlated in all groups, which indicated involvement of the HMGB1/TLR4 signaling pathway. The FEV was negatively correlated with the protein expression levels of TLR4 and HMGB1. Thus, the protective effect of ulinastatin in the lungs of rats with COPD is associated with changes in the HMGB1/TLR4 signaling pathway.

Ulinastatin Supplementation During Human Amniotic Membrane Preservation to Improve its Viability

PURPOSE

The amniotic membrane (AM) is the transparent innermost layer of the placenta and it facilitates rapid wound healing in a diversity of ocular surface disorders. However, extended periods of cryopreservation before use induce significant impairment of cell viability due to oxidative stresses and inflammatory responses. We investigated the effect of supplementing ulinastatin (ULI), a known serine protease inhibitor, and relevant mechanisms of action in AM preservation solution through the hypothermic continuum on inflammatory and apoptotic signals and viability of AM tissue.

MATERIALS AND METHODS

The expression of inflammatory signal factors, including high mobility group box 1 (HMGB1), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), receptor-interacting serine/threonine-protein kinase 3 (RIPK3) and anti-TNF-inducible gene 6 (TSG-6) which is a TNF-α-inducible anti-inflammatory protein, and the expression of apoptotic signal factors, including caspase (Cas)-9 and Cas-8, the initiators, and Cas-3, the executioner caspase and Bax were analyzed with or without ULI during hypothermic preservation of human AM. Subsequently, the actual viability of human AM tissue was verified with or without ULI supplementation throughout hypothermic continuum (both hypothermic- and cryopreservation).

RESULTS

Hypothermic AM preservation with ULI for 48 h resulted in downregulated expression of cold-inducible inflammatory factors, including HMGB1 and NF-κB, as well as RIPK3. In addition, ULI suppressed apoptotic signals related with Cas-9, Cas-8, and Cas-3 under hypothermic conditions. Furthermore, ULI supplementation during hypothermic- and cryopreservation of AM significantly enhanced viability of AM tissue and amniotic epithelial cells.

CONCLUSIONS

Supplementation of ULI during human AM preservation through the hypothermic continuum may be a feasible dual anti-inflammatory and anti-apoptotic strategy that enhances the viability of AM tissue.

Ulinastatin did not reduce mortality in elderly multiple organ failure patients: a retrospective observational study in a single center ICU

Aim

Our aim was to evaluate the effect of ulinastatin on 28‐day mortality in patients who developed multiple organ failure (MOF) related to their acute illness and were admitted to the intensive care unit (ICU).

Methods

We carried out a retrospective observational study of MOF patients in a general ICU of a tertiary care hospital in Japan from January 2009 to December 2012. The primary outcome was 28‐day all‐cause mortality. Secondary outcomes were ventilator‐free days, ICU‐free days, and vasopressor‐free days at day 28. We investigated the association between ulinastatin treatment and outcomes using multivariable regression analysis.

Results

A total of 212 MOF patients were included, 79 (37%) of whom received ulinastatin. The median age was 70 years (interquartile range, 60–77) and median APACHE II score was 25 (interquartile range, 19–29). Overall 28‐day mortality was 20%. There were no significant differences between the ulinastatin group and the control group in age, gender, or APACHE II score. The ulinastatin group had higher prevalence of sepsis (44% versus 22%, P = 0.001). Multivariable logistic regression analysis showed that ulinastatin was not associated with 28‐day mortality (odds ratio = 1.22; 95% confidence interval, 0.54–2.79). Moreover, ulinastatin did not reduce the mortality in patients with sepsis (odds ratio = 1.92; 95% confidence interval, 0.52–7.13). However, ICU‐free days and ventilator‐free days was significantly fewer in the ulinastatin group than control group.

Conclusions

In this retrospective observational study, ulinastatin was not associated with mortality in elderly patients with established MOF, although it might be related to patient's utility.

Ulinastatin attenuates diabetes-induced cardiac dysfunction by the inhibition of inflammation and apoptosis

Ulinastatin exhibits anti-inflammatory activity and protects the heart from ischemia/reperfusion injury. However, whether ulinastatin has a protective effect in diabetic cardiomyopathy is yet to be elucidated. The aim of the present study was to investigate the protective effects of ulinastatin against diabetic cardiomyopathy and its underlying mechanisms. A C57/BL6J mice model of diabetic cardiomyopathy was used and mice were randomly assigned to three groups: Control group, diabetes mellitus (DM) group and DM + ulinastatin treatment group. Cardiac function was assessed using echocardiography and the level of inflammatory cytokine high mobility group box 1 (HMGB1) expression was measured using histopathological examination and reverse transcription-quantitative polymerase chain reaction. The levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 were measured using western blotting and ELISA. The apoptosis rate in the myocardium was assessed by TUNEL assay. Caspase-3 activation, expression of B-cell lymphoma 2 (Bcl-2) and Bcl-2 associated × (Bax) were measured using western blotting, as was the activity of the mitogen activated protein kinase (MAPK) signaling pathway. The results indicated that ulinastatin significantly improved cardiac function in mice with DM. Ulinastatin treatment significantly downregulated HMGB1, TNF-α and IL-6 expression (P<0.05) and significantly reduced the percentage of apoptotic cardiomyocytes (P<0.05) via reduction of caspase-3 activation and the ratio of Bax/Bcl-2 in diabetic hearts (P<0.05). In addition, ulinastatin attenuated the activation of the MAPK signaling pathway. In conclusion, ulinastatin had a protective effect against DM-induced cardiac dysfunction in a mouse model. This protective effect may be associated with the anti-inflammatory and anti-apoptotic abilities of ulinastatin via the MAPK signaling pathway.

Glycyrrhetinic acid prevents acetaminophen-induced acute liver injury via the inhibition of CYP2E1 expression and HMGB1-TLR4 signal activation in mice

Acetaminophen (APAP) is a widely used antipyretic and analgesic drug, which is safe and effective at the therapeutic dose. Unfortunately, excessive dosage of APAP could cause severe liver injury due to lack of effective therapy. Successful therapeutic strategies are urgently requested in clinic. Glycyrrhetinic acid (GA), derived from a traditional medicine licorice, has been shown to exert anti-inflammatory and antioxidant actions. In this study, the effect and the underlying mechanism of GA on APAP-induced hepatotoxicity were explored. Our results showed that pretreatment with GA significantly reduced serum ALT and AST activities, alleviated hepatic pathological damages with hepatocellular apoptosis, down-regulated expression of CYP2E1 mRNA and protein, increased GSH levels, and reduced reactive oxygen species (ROS) productions in the liver of APAP-exposed mice. Furthermore, GA obviously inhibited APAP-induced HMGB1-TLR4 signal activation, as evaluated by reduced hepatic HMGB1 release, p-IRAK1, p-MAPK and p-IκB expression as well as the productions of TNF-α and IL-1β. In addition, GA attenuated hepatic neutrophils recruitment and macrophages infiltration caused by APAP. These findings reflected that GA could alleviate APAP-induced hepatotoxicity, the possible mechanism is associated with down-regulation of CYP2E1 expression and deactivation of HMGB1-TLR4 signal pathway.

Effect of ulinastatin, a human urinary protease inhibitor, on heatstroke-induced apoptosis and inflammatory responses in rats

Ulinastatin has been demonstrated to protect against heatstroke by reducing cerebral ischemia and damage in rats. In order to extend these observations, apoptosis and systemic inflammatory responses were assessed in rats treated with ulinastatin prior to the initiation of heatstroke. Following the onset of heatstroke, histological analysis revealed that the hippocampal tissues displayed edema and damage. In addition, upregulation of malondialdehyde, inducible nitric oxide synthase (iNOS) and reactive oxygen species and downregulation of superoxide dismutase were observed compared with the respective levels in the control group. Furthermore, TUNEL staining and western blotting assays indicated that heatstroke induced cell apoptosis by increasing the Bax/Bcl-2 ratio and caspase-3 levels, and upregulating the protein expression levels of nuclear factor-κB, cyclooxygenase-2 and iNOS. However, the injury induced by heatstroke was significantly inhibited by ulinastatin pretreatment at doses of 5,000 and 10,000 IU/kg. Survival analysis of the rats subjected to heatstroke demonstrated that rats treated with ulinastatin at a dose of 10,000 IU/kg lived longer than those that did not receive ulinastatin treatment. These observations indicate that ulinastatin may protect against heatstroke by reducing apoptosis and systemic inflammatory responses.

Mitochondrial Dysfunction and Autophagy in Hepatic Ischemia/Reperfusion Injury

Ischemia/reperfusion (I/R) injury remains a major complication of liver resection, transplantation, and hemorrhagic shock. Although the mechanisms that contribute to hepatic I/R are complex and diverse involving the interaction of cell injury in hepatocytes, immune cells, and endothelium, mitochondrial dysfunction is a cardinal event culminating in hepatic reperfusion injury. Mitochondrial autophagy, so-called mitophagy, is a key cellular process that regulates mitochondrial homeostasis and eliminates damaged mitochondria in a timely manner. Growing evidence accumulates that I/R injury is attributed to defective mitophagy. This review aims to summarize the current understanding of autophagy and its role in hepatic I/R injury and highlight the various therapeutic approaches that have been studied to ameliorate injury.

HMGB1 Turns Renal Tubular Epithelial Cells into Inflammatory Promoters by Interacting with TLR4 During Sepsis

Our study was undertaken to investigate whether the inflammatory mediator high-mobility group box 1 (HMGB1) can enter the renal tissue and urine and what is the functional change of renal tubular epithelial cells (TECs) interacting with HMGB1 during sepsis. We found that the transcription levels of interleukin 1 (IL-1) and interleukin 6 (IL-6) mRNA in TECs increased significantly during sepsis and these processes can be blocked by splenectomy. We also found out HMGB1 accumulated in the renal tissue and entered urine during sepsis and toll-like receptor 4 (TLR4) was expressed by TECs. In vitro, we demonstrated that HMGB1 induced MAPK and NF-κB activation and G1 cell cycle arrest in TECs. We also found that the mRNA transcription levels of IL-1, IL-6, and tissue inhibitor of metalloproteinases 2 (TIMP2) increased significantly and the IL-1, IL-6, and TIMP2 can be secreted by TECs stimulated by HMGB1. In contrast, LPS RS can block all of the processes above in vitro. In vivo, the increase of the mRNA transcription level of TIMP2 was also observed. These data indicate that HMGB1 accumulates in renal tissue and enters the urine and the interaction between HMGB1 and TLR4 turns TECs into inflammatory promoters during sepsis.

Continuous hemodiafiltration therapy reduces damage of multi-organs by ameliorating of HMGB1/TLR4/NFκB in a dog sepsis model

In the present study, we investigated whether CVVH can reduce HMGB1, TLR4, NF-κB and other serum cytokine levels, preventing organ injury in a dog sepsis model. A total of 10 dogs were injected with LPS and treated with either CVVH group (n = 5) or nothing (Control, n = 5) for 24 h. EILSA was used for examining the concentration of TNF-α, IL-6, HMGB 1 and TLR4. The histological change of lung, liver and kidney tissues was determined. The mRNA expression of HMGB1, TLR4 and NF-κB was examined by RT-PCR. The protein of HMGB1 and phosphated NF-κB was examined by Western-blot. The levels of serum HMGB1 came to the peak at 8 h, 16 h and then declined. The LPS-induced increase in HMGB1 level was suppressed by CVVH compared with Control. Likewise, serum TNF-α and IL-6 levels decreased with CVVH along with a significant improvement in the function of main organs. Histologic examination revealed significant reduction in inflammation in lung; liver and kidney tissues harvested 24 h after CVVH compared with Control. The mRNA of HMGB1, TLR4 and NF-κB in the kidney was expressed at high level after LPS administration, which was significantly decreased by CVVH. The increased protein expression of HMGB1 and phosphated NF-κB was reduced after CVVH compared with control. CVVH by reducing the level of HMGB1, TLR4, NF-κB and other cytokines could weaken the cascade of cytokines and restore the immune system, and reduce the damage of important organs in sepsis.

Ulinastatin inhibits oxidant-induced endothelial hyperpermeability and apoptotic signaling

Oxidants are important signaling molecules known to increase endothelial permeability. Studies implicate reactive oxygen species (ROS) and the intrinsic apoptotic signaling cascades as mediators of vascular hyperpermeability. Here we report the protective effects of ulinastatin, a serine protease inhibitor with antiapoptotic properties, against oxidant-induced endothelial monolayer hyperpermeability. HUVECs were respectively pretreated with 10,000 and 50,000 u/l ulinastatin, followed by stimulation of 0.6 mM H₂O₂. Monolayer permeability was determined by transendothelial electrical resistance (TER); Mitochondrial release of cytochrome c was determined by enzyme-linked immunosorbent assay; Caspase-3 activity was measured by fluorometric assay; Adherens junction protein β-catenin was detected by immunofluorescense staining; Ratio of cell apoptosis was evaluated by Annexin-V/PI double stain assay; Mitochondrial membrane potential (Δψm) was determined with JC-1; Intracellular ATP content was assayed by a commercial kit; Bax and Bcl-2 expression were estimated by western blotting; Intracellular reactive oxygen species (ROS) level was measured by DCFH-DA. H₂O₂ exposure resulted in endothelial hyperpermeability and ROS formation (P < 0.05). The activation of mitochondrial intrinsic apoptotic signaling pathway was evidenced from BAX up-regulation, Bcl-2 down-regulation, mitochondrial depolarization, an increase in cytochrome c release, and activation of caspase-3 (P < 0.05). UTI (50,000 u/l) attenuated endothelial hyperpermeability, ROS formation, mitochondrial dysfunction, cytochrome c release, activation of caspase-3, and disruption of cell adherens junctions (P < 0.05). Together, these results demonstrate that UTI provides protection against vascular hyperpermeability by modulating the intrinsic apoptotic signaling.