Downregulation of HMGB1 protects against the development of acute lung injury after severe acute pancreatitis

DGA ameliorates severe acute pancreatitis through modulating macrophage pyroptosis

Severe acute pancreatitis (SAP) is an inflammatory disease with varying severity, ranging from mild local inflammation to severe systemic disease, with a high incidence rate and mortality. Current drug treatments are not ideal. Therefore, safer and more effective therapeutic drugs are urgently needed. 7α,14β-dihydroxy-ent-kaur-17-dimethylamino-3,15-dione DGA, a diterpenoid compound derivatized from glaucocalyxin A, exhibits anti-inflammatory activity. In this study, we demonstrated the therapeutic potential of DGA against SAP and elucidated the underlying mechanisms. Treatment with DGA markedly (1) inhibited death of RAW264.7 and J774a.1 cells induced by Nigericin and lipopolysaccharide, (2) alleviated edema, acinar cell vacuolation, necrosis, and inflammatory cell infiltration of pancreatic tissue in mice, and (3) inhibited the activity of serum lipase and the secretion of inflammatory factor IL-1β. DGA significantly reduced the protein expression of IL-1β and NLRP3 and inhibited the phosphorylation of NF-κB. However, DGA exhibited no inhibitory effect on the expression of caspase-1, gasdermin D (GSDMD), NF-κB, TNF-α, or apoptosis-associated speck-like protein (ASC) and on the cleavage of caspase-1 or GSDMD. Molecular docking simulation confirmed that DGA can bind to TLR4 and IL-1 receptor. In conclusion, DGA may effectively alleviate the symptoms of SAP in mice and macrophages by inhibiting the binding of TLR4 and IL-1 receptor to their ligands; therefore, DGA is a promising drug candidate for the treatment of patients with SAP.

Urolithin A exerts a protective effect on lipopolysaccharide-induced acute lung injury by regulating HMGB1-mediated MAPK and NF-κB signaling pathways

Acute lung injury (ALI) is a severe inflammatory disorder that has a high morbidity and mortality rate. Urolithin A (UA) is reported to have anti-inflammatory and anti-oxidative effects in ALI. However, its molecular mechanisms in ALI remain to be explored. Mice and BEAS-2B cells were administrated with lipopolysaccharide (LPS) to mimic the ALI model in vivo and in vitro. Hematoxylin-eosin (HE) staining was used to detect the pathological injury of lung tissues. The levels of proinflammatory cytokines in bronchoalveolar lavage fluid (BALF) and culture supernatant and the levels of oxidative stress markers in lung tissues were measured using ELISA. DCFH-DA probe was used to assess the reactive oxygen species (ROS) level. TUNEL staining and flow cytometry were performed to determine cell apoptosis. The key targets and pathways were confirmed by immunohistochemistry (IHC) and western blot. UA suppressed the pathologic damage, wet/dry weight ratio, and total protein and inflammatory cells in BALF. UA decreased neutrophil infiltration and proinflammatory cytokines production. UA reduced the level of malondialdehyde (MDA) and increased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in pulmonary tissues. UA also inhibited cell apoptosis in lung tissues by decreasing Bax expression and increasing Bcl-2 expression. In addition, UA suppressed LPS-induced inflammatory factor production, ROS level, and cell apoptosis in BEAS-2B. Importantly, UA decreased the expression of HMGB1 in LPS-treated mice and BEAS-2B cells. HMGB1 overexpression greatly abrogated the inhibition of UA on inflammation, ROS, and cell apoptosis in LPS-administrated BEAS-2B. Furthermore, UA treatment suppressed the phosphorylated levels of p38, JNK, ERK, and p65 in LPS-administrated mice and BEAS-2B cells. UA alleviated lung inflammation, oxidative stress, and apoptosis in ALI by targeting HMGB1 to inactivate the MAPK/NF-κB signaling, suggesting the potential of UA to treat ALI.

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.

Fighting Fire with Fire: Exosomes and Acute Pancreatitis-Associated Acute Lung Injury

Acute pancreatitis (AP) is a prevalent clinical condition of the digestive system, with a growing frequency each year. Approximately 20% of patients suffer from severe acute pancreatitis (SAP) with local consequences and multi-organ failure, putting a significant strain on patients' health insurance. According to reports, the lungs are particularly susceptible to SAP. Acute respiratory distress syndrome, a severe type of acute lung injury (ALI), is the primary cause of mortality among AP patients. Controlling the mortality associated with SAP requires an understanding of the etiology of AP-associated ALI, the discovery of biomarkers for the early detection of ALI, and the identification of potentially effective drug treatments. Exosomes are a class of extracellular vesicles with a diameter of 30-150 nm that are actively released into tissue fluids to mediate biological functions. Exosomes are laden with bioactive cargo, such as lipids, proteins, DNA, and RNA. During the initial stages of AP, acinar cell-derived exosomes suppress forkhead box protein O1 expression, resulting in M1 macrophage polarization. Similarly, macrophage-derived exosomes activate inflammatory pathways within endothelium or epithelial cells, promoting an inflammatory cascade response. On the other hand, a part of exosome cargo performs tissue repair and anti-inflammatory actions and inhibits the cytokine storm during AP. Other reviews have detailed the function of exosomes in the development of AP, chronic pancreatitis, and autoimmune pancreatitis. The discoveries involving exosomes at the intersection of AP and acute lung injury (ALI) are reviewed here. Furthermore, we discuss the therapeutic potential of exosomes in AP and associated ALI. With the continuous improvement of technological tools, the research on exosomes has gradually shifted from basic to clinical applications. Several exosome-specific non-coding RNAs and proteins can be used as novel molecular markers to assist in the diagnosis and prognosis of AP and associated ALI.

Damage associated molecular patterns and neutrophil extracellular traps in acute pancreatitis

Previous researches have emphasized a trypsin-centered theory of acute pancreatitis (AP) for more than a century. With additional studies into the pathogenesis of AP, new mechanisms have been explored. Among them, the role of immune response bears great importance. Pro-inflammatory substances, especially damage-associated molecular patterns (DAMPs), play an essential role in activating, signaling, and steering inflammation. Meanwhile, activated neutrophils attach great importance to the immune defense by forming neutrophil extracellular traps (NETs), which cause ductal obstruction, premature trypsinogen activation, and modulate inflammation. In this review, we discuss the latest advances in understanding the pathological role of DAMPs and NETs in AP and shed light on the flexible crosstalk between these vital inflammatory mediators. We, then highlight the potentially promising treatment for AP targeting DAMPs and NETs, with a focus on novel insights into the mechanism, diagnosis, and management of AP.

The Mechanism of Lung and Intestinal Injury in Acute Pancreatitis: A Review

Acute pancreatitis (AP), as a common cause of clinical acute abdomen, often leads to multi-organ damage. In the process of severe AP, the lungs and intestines are the most easily affected organs aside the pancreas. These organ damages occur in succession. Notably, lung and intestinal injuries are closely linked. Damage to ML, which transports immune cells, intestinal fluid, chyle, and toxic components (including toxins, trypsin, and activated cytokines to the systemic circulation in AP) may be connected to AP. This process can lead to the pathological changes of hyperosmotic edema of the lung, an increase in alveolar fluid level, destruction of the intestinal mucosal structure, and impairment of intestinal mucosal permeability. The underlying mechanisms of the correlation between lung and intestinal injuries are inflammatory response, oxidative stress, and endocrine hormone secretion disorders. The main signaling pathways of lung and intestinal injuries are TNF-α, HMGB1-mediated inflammation amplification effect of NF-κB signal pathway, Nrf2/ARE oxidative stress response signaling pathway, and IL-6-mediated JAK2/STAT3 signaling pathway. These pathways exert anti-inflammatory response and anti-oxidative stress, inhibit cell proliferation, and promote apoptosis. The interaction is consistent with the traditional Chinese medicine theory of the lung being connected with the large intestine (fei yu da chang xiang biao li in Chinese). This review sought to explore intersecting mechanisms of lung and intestinal injuries in AP to develop new treatment strategies.

Calycosin attenuates severe acute pancreatitis-associated acute lung injury by curtailing high mobility group box 1 - induced inflammation

BACKGROUND

Acute lung injury (ALI) is a common and life-threatening complication of severe acute pancreatitis (SAP). There are currently limited effective treatment options for SAP and associated ALI. Calycosin (Cal), a bioactive constituent extracted from the medicinal herb Radix Astragali exhibits potent anti-inflammatory properties, but its effect on SAP and associated ALI has yet to be determined.

AIM

To identify the roles of Cal in SAP-ALI and the underlying mechanism.

METHODS

SAP was induced via two intraperitoneal injections of L-arg (4 g/kg) and Cal (25 or 50 mg/kg) were injected 1 h prior to the first L-arg challenge. Mice were sacrificed 72 h after the induction of SAP and associated ALI was examined histologically and biochemically. An in vitro model of lipopolysaccharide (LPS)-induced ALI was established using A549 cells. Immunofluorescence analysis and western blot were evaluated in cells. Molecular docking analyses were conducted to examine the interaction of Cal with HMGB1.

RESULTS

Cal treatment substantially reduced the serum amylase levels and alleviated histopathological injury associated with SAP and ALI. Neutrophil infiltration and lung tissue levels of neutrophil mediator myeloperoxidase were reduced in line with protective effects of Cal against ALI in SAP. Cal treatment also attenuated the serum levels and mRNA expression of pro-inflammatory cytokines tumor necrosis factor-α, interleukin-6, IL-1β, HMGB1 and chemokine (CXC motif) ligand 1 in lung tissue. Immunofluorescence and western blot analyses showed that Cal treatment markedly suppressed the expression of HMGB1 and phosphorylated nuclear factor-kappa B (NF-κB) p65 in lung tissues and an in vitro model of LPS-induced ALI in A549 cells suggesting a role for HGMB1 in the pathogenesis of ALI. Furthermore, molecular docking analysis provided evidence for the direct interaction of Cal with HGMB1.

CONCLUSION

Cal protects mice against L-arg-induced SAP and associated ALI by attenuating local and systemic neutrophil infiltration and inflammatory response via inhibition of HGMB1 and the NF-κB signaling pathway.

Targeting HMGB1/TLR4/NF-κB signaling pathway by protocatechuic acid protects against l-arginine induced acute pancreatitis and multiple organs injury in rats

Acute pancreatitis (AP) is a common pancreatic inflammation associated with substantial morbidity and mortality. AP may be mild or severe which can spread systemically causing multiple organs failure (MOF) and even death. In the current study, protocatechuic acid (PCA), a natural phenolic acid, was investigated for its possible protective potential against L-arginine induced AP and multiple organs injury (MOI) in rats. AP was induced by L-arginine (500 mg/100 g, ip). Two dose levels of PCA were tested (50 and 100 mg/kg, oral, 10 days before L-arginine injection). PCA successfully protected against L-arginine induced AP and MOI that was manifested by normalizing pancreatic, hepatic, pulmonary, and renal tissue architecture and restoring the normal values of pancreatic enzymes (amylase and lipase), serum total protein, liver enzymes (alanine transaminase (ALT) and aspartate transaminase (AST)) and kidney function biomarkers (blood urea nitrogen (BUN) and serum creatinine (Cr)) that were significantly elevated upon L-arginine administration. Additionally, PCA restored balanced oxidant/antioxidants status that was disrupted by L-arginine and normalized pancreatic levels of inducible nitric oxide synthase (iNOS) and nitric oxide (NO) content. Moreover, PCA significantly decreased L-arginine induced elevation in pancreatic high motility group box protein 1 (HMGB1), toll like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), nuclear factor kappa B (NF-κB), tumor necrosis factor- α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) expression. PCA significantly ameliorated L-arginine-induced AP and MOI through its anti-inflammatory and antioxidant effects. HMGB1/TLR4/NF-κB was the major pathway involved in the observed protective potential.

CTRP3 ameliorates cerulein-induced severe acute pancreatitis in mice via SIRT1/NF-κB/p53 axis

Severe acute pancreatitis (SAP) is a common and life-threatening clinical acute abdominal disease. C1q/tumor necrosis factor-related protein 3 (CTRP3), a novel paralog of adiponectin, has been identified as a crucial regulator in multiple types of inflammatory disorders. However, the biological role of CTRP3 in SAP remains poorly understood. The present study aimed to characterize the role of CTRP3 in SAP and illuminate the potential mechanisms involved. In the current study, SAP mouse models were induced by seven hourly intraperitoneal injection of cerulein (50 μg/kg) and an immediate intraperitoneal injection of lipopolysaccharide (10 mg/kg) after the last cerulein administration. Histological examination and serological analysis demonstrated that SAP mouse models were successfully established. Herein, we found that CTRP3 expression was significantly decreased in the pancreatic tissues of SAP mice compared with normal control mice. Furthermore, we explored the effects of CTRP3 rescue in SAP mice and discovered that CTRP3 overexpression attenuated pathological lesions, inhibited inflammatory mediator release and repressed acinar cell apoptosis. Notably, mechanistic studies revealed that CTRP3 overexpression suppressed NF-κB p65 phosphorylation and p53 acetylation to alleviate cerulein-induced SAP in mouse models through activation of silent information regulator 1 (SIRT1), a nicotinamide adenine dinucleotide-dependent protein deacetylase. Collectively, our data indicate that CTRP3 may exert its protective effects in SAP mice via regulation of SIRT1-mediated NF-κB and p53 signaling pathways, implying a promising therapeutic strategy against SAP.

Intestinal barrier damage, systemic inflammatory response syndrome, and acute lung injury: A troublesome trio for acute pancreatitis

Severe acute pancreatitis (SAP), a serious inflammatory disease of the pancreas, can easily lead to systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndromes (MODS). Acute lung injury (ALI) is one of the most serious complications of SAP. However, the specific pathogenesis of SAP-associated ALI is not fully understood. Crosstalk and multi-mechanisms involving pancreatic necrosis, bacteremia, intestinal barrier failure, activation of inflammatory cascades and diffuse alveolar damage is the main reason for the unclear pathological mechanism of SAP-associated ALI. According to previous research on SAP-associated ALI in our laboratory and theories put forward by other scholars, we propose that the complex pattern of SAP-associated ALI is based on the "pancreas-intestine-inflammation/endotoxin-lung (P-I-I/E-L) pathway". In this review, we mainly concentrated on the specific details of the "P-I-I/E-L pathway" and the potential treatments or preventive measures for SAP-associated ALI.

NLRP3 Inflammasome-Mediated Inflammation in Acute Pancreatitis

The discovery of inflammasomes has enriched our knowledge in the pathogenesis of multiple inflammatory diseases. The NLR pyrin domain-containing protein 3 (NLRP3) has emerged as the most versatile and well-characterized inflammasome, consisting of an intracellular multi-protein complex that acts as a central driver of inflammation. Its activation depends on a tightly regulated two-step process, which includes a wide variety of unrelated stimuli. It is therefore not surprising that the specific regulatory mechanisms of NLRP3 inflammasome activation remain unclear. Inflammasome-mediated inflammation has become increasingly important in acute pancreatitis, an inflammatory disorder of the pancreas that is one of the fatal diseases of the gastrointestinal tract. This review presents an update on the progress of research into the contribution of the NLRP3 inflammasome to acute pancreatic injury, examining the mechanisms of NLRP3 activation by multiple signaling events, the downstream interleukin 1 family of cytokines involved and the current state of the literature on NLRP3 inflammasome-specific inhibitors.

MicroRNAs in acute pancreatitis: From pathogenesis to novel diagnosis and therapy

Acute pancreatitis (AP) is an inflammatory disorder initiated by activation of pancreatic zymogens, leading to pancreatic injury and systemic inflammatory response. MicroRNAs (miRNAs) have emerged as important regulators of gene expression and key players in human physiological and pathological processes. Discoveries over the past decade have confirmed that altered expression of miRNAs is implicated in the pathogenesis of AP. Indeed, a number of miRNAs have been found to be dysregulated in various cell types involved in AP such as acinar cells, macrophages, and lymphocytes. These aberrant miRNAs can regulate acinar cell necrosis and apoptosis, local and systemic inflammatory response, thereby contributing to the initiation and progression of AP. Moreover, patients with AP possess unique miRNA signatures when compared with healthy individuals or those with other diseases. In view of their stability and easy detection, therefore, miRNAs have the potential to act as biomarkers for the diagnosis and assessment of patients with AP. In this review, we provide an overview of the novel cellular and molecular mechanisms underlying the roles of miRNAs during the disease processes of AP, as well as the potential diagnosis and therapeutic biomarkers of miRNAs in patients with AP.

PKR suppress NLRP3-pyroptosis pathway in lipopolysaccharide-induced acute lung injury model of mice

To explore the effect of double-stranded RNA-dependent kinase (PKR) in acute lung injury (ALI) and resultant acute respiratory distress syndrome (ARDS). A mouse model of lipopolysaccharide (LPS)-induced ALI was used to evaluate the levels of phosphorylated (p)-PKR and NLRP3 in lung tissue, and the protective effects of a PKR inhibitor on lung injury. And in vitro, macrophages were incubated with LPS, with or without PKR inhibitor pre-treatment. It was observed that the levels of p-PKR protein and NLRP3 protein were significantly increased compared with those in control tissues after LPS administration. Meanwhile, treatment with PKR inhibitor decreased inflammation, injury score, wet/dry weight ratio, bronchoalveolar lavage fluid (BALF) protein levels, neutrophil count in BALF, myeloperoxidase activity and expression of high-mobility group box1(HMGB1) and interleukin(IL)-1β in the lungs of LPS-challenged mice. In vitro, we demonstrated that the levels of p-PKR and NLRP3, and cell mortality rate were increased in macrophages which were incubated with LPS compared with those without LPS administration, and PKR inhibitor significantly suppressed the level of NLRP3, caspase-1, HMGB1 and IL-1β. These results indicate that PKR plays a key role in ALI through NLRP3-pyrotosis pathway and pharmacological inhibition of PKR may have potential therapeutic effects in the treatment of patients with ALI and ARDS.

Effects of Tec Tyrosine Kinase Inhibition on the Inflammatory Response of Severe Acute Pancreatitis-Associated Acute Lung Injury in Mice

BACKGROUND

The Tec kinase family is involved in acute and chronic inflammatory diseases, but its relationship with severe acute pancreatitis (SAP) remains unclear.

AIMS

To investigate whether Tec tyrosine kinase can be used as a target for severe acute pancreatitis-associated acute lung injury (PALI).

METHODS

A total of 90 mice were randomly assigned into four groups: SAP (n = 15), control (n = 15), SAP + α-cyano-β-hydroxy-β-methyl-N-(2,5-dibromophenyl)propenamide (LFM-A13) (pretreated with Tec kinase inhibitor LFM-A13, n = 15), and SAP + Tec siRNA (pretreated with PBS/negative control siRNA/Tec siRNA, n = 45). SAP was induced by caerulein and lipopolysaccharide. Animals were sacrificed at 0, 3, 24, 48, and 72 h, respectively. Pathological changes and scores of the lung and pancreas were determined using hematoxylin-eosin staining. Expression of Tec and phosphorylated Tec (p-Tec) were examined by real-time polymerase chain reaction, Western blot, and immunoprecipitation. Serum levels of amylase, myeloperoxidase, and pro-inflammatory cytokines were measured by ELISA.

RESULTS

The expression of Tec in lung tissue was significantly higher in the SAP group than in the control group (p < 0.05), and p-Tec expression gradually increased with time. Furthermore, p-Tec expression was significantly lower in the SAP + LFM-A13 group than in the SAP group (p < 0.05); however, Tec expression did not vary. Tec inhibitors, LFM-A13 and Tec siRNA, alleviated pathological damage and release of inflammatory cytokines (p < 0.05).

CONCLUSIONS

Tec tyrosine kinase plays a key role in PALI, and is therefore a potential target for clinical treatment.

Indomethacin down-regulating HMGB1 and TNF-α to prevent pancreatitis after endoscopic retrograde cholangiopancreatography

Background and aims: Several articles demonstrated that non-steroidal anti-inflammation drugs (NSAIDs) were effective in reducing the incidence of pancreatitis after endoscopic retrograde cholangiopancreatography (PEP). However, studies revealed inconsistent results. The mechanism of NSAIDs in preventing PEP is still little known. Therefore, the aim of our study was to evaluate the efficacy of NSAIDs for PEP prophylaxis and further to explore the mechanism of NSAIDs for prevention of PEP. Methods: Patients who underwent endoscopic retrograde cholangiopancreatography (ERCP) were randomly assigned to receive 100 mg rectal indomethacin or glycerin suppository 15-20 min before ERCP. The primary outcome was the rate of PEP. And the levels of serum HMGB1 and TNF-α were also measured before ERCP and 3 and 24 h after ERCP. Univariate analysis and multivariate analysis were carried out to estimate the independent risk factors for PEP. Results: Totally, 100 patients were enrolled, 50 received indomethacin and 50 with placebo (glycerin suppository). PEP developed in six patients in indomethacin group and 16 in the control group, the difference was significant (p = .016). The levels of HMGB1 and TNF-α were significantly decreased in indomethacin group at 3 (p < .0001) and 24 h (p < .0001) after ERCP, compared to the control group. Multivariate analysis revealed that duration of ERCP (OR, 0.221; 95% CI, 0.072-0.680; p = .008) and usage of NSAIDs (OR, 0.278; 95% CI, 0.090-0.861; p = .026) were independent predictors of PEP. Conclusions: Rectal indomethacin could significantly reduce the risk of PEP by down-regulating the levels of HMGB1 and TNF-α.

Exogenous surfactant prevents hyperoxia-induced lung injury in adult mice

Background

In addition to the risk of developing ventilator-induced lung injury, patients with ARDS are at risk of developing hyperoxic injury due the supra-physiological oxygen supplementation clinically required to reverse hypoxemia. Alterations of endogenous surfactant system participate in the pulmonary dysfunction observed in ARDS. Administration of exogenous surfactant could have protective effects during hyperoxia.

Methods

Male BALB/c mice (8–10 weeks), a strain highly sensitive to hyperoxia, received the exogenous surfactant-containing protein SP-B and SP-C by intranasal instillation 12 h before starting 24 h of exposure to hyperoxia in an inhalation chamber and were compared to mice receiving hyperoxia alone and to controls subjected to normoxia.

Results

Compared to the hyperoxia group, the administration of exogenous surfactant was able to reduce lung inflammation through a reduction in the influx of neutrophils and inflammatory biomarkers such as TNF, IL-17, and HMGB1 expression. The antioxidant activity prevented oxidative damage by reducing lipid peroxidation and protein carbonylation and increasing superoxide dismutase activity when compared to the hyperoxia group.

Conclusion

Our results offer new perspectives on the effects and the mechanism of exogenous surfactant in protecting the airway and lungs, in oxygen-rich lung microenvironment, against oxidative damage and aggravation of acute inflammation induced by hyperoxia.

DAMPs and sterile inflammation in drug hepatotoxicity

Drug hepatotoxicity is the leading cause of acute liver failure (ALF) in the developed countries. The early diagnosis and treatment are still problematic, and one important reason is the lack of reliable mechanistic biomarkers and therapeutic targets; therefore, searching for new biomarkers and therapeutic targets is urgent. Drug hepatotoxicity induces severe liver cells damage and death. Dead and damaged cells release endogenous damage-associated molecular patterns (DAMPs). Increased circulating levels of DAMPs (HMGB1, histones and DNA) can reflect the severity of drug hepatotoxicity. Elevated plasma HMGB1 concentrations can serve as early and sensitive mechanistic biomarker for clinical acetaminophen hepatotoxicity. DAMPS significantly contribute to liver injury and inhibiting the release of DAMPs ameliorates experimental hepatotoxicity. In addition, HMGB1 mediates 80% of gut bacterial translocation (BT) during acetaminophen toxicity. Gut BT triggers systemic inflammation, leading to multiple organ injury and mortality. Moreover, DAMPs can trigger and extend sterile inflammation, which contributes to early phase liver injury but improves liver regeneration at the late phase of acetaminophen overdose, because anti-inflammatory treatment reduces liver injury at early phase but impairs liver regeneration at late phase of acetaminophen toxicity, whereas pro-inflammatory therapy improves late phase liver regeneration. DAMPs are promising mechanistic biomarkers and could also be the potential therapeutic targets for drug hepatotoxicity. DAMPs-triggered sterile inflammation contributes to liver injury at early phase but improves liver regeneration at later phase of acetaminophen hepatotoxicity; therefore, anti-inflammatory therapy would be beneficial at early phase but should be avoided at the late phase of acetaminophen overdose.

Short-term physiological hypoxia potentiates the therapeutic function of mesenchymal stem cells

Background

In the bone marrow, MSCs reside in a hypoxic milieu (1–5% O₂) that is thought to preserve their multipotent state. Typically, in vitro expansion of MSCs is performed under normoxia (~ 21% O₂), a process that has been shown to impair their function. Here, we evaluated the characteristics and function of MSCs cultured under hypoxia and hypothesized that, when compared to normoxia, dedicated hypoxia will augment the functional characteristics of MSCs.

Methods

Human and porcine bone marrow MSCs were obtained from fresh mononuclear cells. The first study evaluated MSC function following both long-term (10 days) and short-term (48 h) hypoxia (1% O₂) culture. In our second study, we evaluated the functional characteristics of MSC cultured under short-term 2% and 5% hypoxia. MSCs were evaluated for their metabolic activity, proliferation, viability, clonogenicity, gene expression, and secretory capacity.

Results

In long-term culture, common MSC surface marker expression (CD44 and CD105) dropped under hypoxia. Additionally, in long-term culture, MSCs proliferated significantly slower and provided lower yields under hypoxia. Conversely, in short-term culture, MSCs proliferated significantly faster under hypoxia. In both long-term and short-term cultures, MSC metabolic activity was significantly higher under hypoxia. Furthermore, MSCs cultured under hypoxia had upregulated expression of VEGF with concomitant downregulation of HMGB1 and the apoptotic genes BCL-2 and CASP3. Finally, in both hypoxia cultures, the pro-inflammatory cytokine, IL-8, was suppressed, while levels of the anti-inflammatories, IL-1ra and GM-CSF, were elevated in short-term hypoxia only.

Conclusions

In this study, we demonstrate that hypoxia augments the therapeutic characteristics of both porcine and human MSCs. Yet, short-term 2% hypoxia offers the greatest benefit overall, exemplified by the increase in proliferation, self-renewing capacity, and modulation of key genes and the inflammatory milieu as compared to normoxia. These data are important for generating robust MSCs with augmented function for clinical applications.

Biomimetic carbon monoxide delivery based on hemoglobin vesicles ameliorates acute pancreatitis in mice via the regulation of macrophage and neutrophil activity

Macrophages play a central role in various inflammatory disorders and are broadly divided into two subpopulations, M1 and M2 macrophage. In the healing process in acute inflammatory disorders, shifting the production of M1 macrophages to M2 macrophages is desirable, because M1 macrophages secrete pro-inflammatory cytokines, whilst the M2 variety secrete anti-inflammatory cytokines. Previous findings indicate that when macrophages are treated with carbon monoxide (CO), the secretion of anti-inflammatory cytokine is increased and the expression of pro-inflammatory cytokines is inhibited, indicating that CO may have a potential to modulate the production of macrophages toward the M2-like phenotype. In this study, we examined the issue of whether CO targeting macrophages using a nanotechnology-based CO donor, namely CO-bound hemoglobin vesicles (CO-HbV), modulates their polarization and show therapeutic effects against inflammatory disorders. The results showed that the CO-HbV treatment polarized a macrophage cell line toward an M2-like phenotype. Furthermore, in an in vivo study using acute pancreatitis model mice as a model of an inflammatory disease, a CO-HbV treatment also tended to polarize macrophages toward an M2-like phenotype and inhibited neutrophil infiltration in the pancreas, resulting in a significant inflammation. In addition to the suppression of acute pancreatitis, CO-HbV diminished a subsequent pancreatitis-associated acute lung injury. This could be due to the inhibition of the systemic inflammation, neutrophil infiltration in the lungs and the production of HMGB-1. These findings suggest that CO-HbV exerts superior anti-inflammatory effects against inflammatory disorders via the regulation of macrophage and neutrophil activity.

Bile and circulating HMGB1 contributes to systemic inflammation in obstructive jaundice

BACKGROUND

Obstructive jaundice (OJ) patients with cholangitis are prone to sepsis; however, the underlying mechanisms are still not clear and need to be clarified.

METHODS

Analyzing all available published data related to the title of this article.

RESULTS

OJ leads to absence of gut luminal bile and accumulation of hepatic and circulating bile acids. Absence of gut luminal bile deprives the gut from its antiinflammatory, endotoxin-binding, bacteriostatic, mucosal-trophic, epithelial tight-junction maintaining, and gut motility-regulating effects, leading to gut bacterial overgrowth, mucosal atrophy, mucosal tight-junction loss, and gut motility dysfunction. These alterations promote intestinal endotoxin and bacterial translocation (BT) into portal and systemic circulation. Gut BT triggers systemic inflammation, which can lead to multiple organ dysfunctions in OJ. The accumulation of hepatic and circulating bile acids kills/damages hepatocyte and Kupffer cells, and it also significantly decreases the number of liver natural killer T-cells in OJ. This results in impaired hepatic and systemic immune function, which facilitates BT. In addition, neutralizing bile HMGB1 can reverse endotoxemic bile-induced gut BT and mucosal injury in mice, suggesting that bile HMGB1 in OJ patients can be responsible for internal drainage-related clinical complications. Moreover, the elevated circulating HMGB1 level may contribute to multiple organ injuries, and it might also mediate gut BT in OJ.

CONCLUSIONS

HMGB1 may significantly contribute to systemic inflammation and multiple organ dysfunctions in OJ.

Augmenter of liver regeneration (ALR) regulates acute pancreatitis via inhibiting HMGB1/TLR4/NF-κB signaling pathway

This research aimed to explore the effect of augmenter of liver regeneration (ALR) in acute pancreatitis (AP) of mice and the underlying mechanism. Caerulein were given to mice to get AP models. AP mice were given saline, ALR plasmids or negative control plasmids. Then, pancreas tissues were fixed and stained for histological examination. The levels of serum amylase, serum lipase, MPO, HMGB1, TNF-α, IL-1β as well as MCP-1 were detected by ELISA assay. The mRNA levels of TLR4, p65, IκBα, iNOS, COX-2 and GAPDH were examined by RT-qPCR. The protein levels of HMGB1, TLR4, MD2, MyD88, IκBα and GAPDH were detected by western blotting. ALR decreased serum amylase as well as lipase levels and alleviated the histopathological alterations of the pancreas in AP mice. ALR decreased the MPO activity of pancreas in AP Mice. ALR decreased the HMGB1/TLR4 signaling pathway in AP Mice. ALR decreased pancreas IL-1β and MCP-1 in AP mice, and also decreased plasma TNF-α and IL-1β in AP mice. ALR attenuated the cerulein-caused increase in p65 mRNA and protein levels, but had no effects on mRNA and protein levels of IκBα. The AP mice significantly promoted the mRNA levels of iNOS and COX-2 that was inhibited by ALR. HNE formation was also increased in AP mice, but it was decreased by ALR. ALR alleviates acute pancreatitis by inhibiting HMGB1/TLR4/NF-κB signaling pathway. It is promising to alleviate the syndromes of patients with acute via targeting ALR.

Effects of penehyclidine hydrochloride on severe acute pancreatitis-associated acute lung injury in rats

Penehyclidine hydrochloride (PHC) is a selective M₁ and M₃ receptor antagonist. This study was designed to investigate the effect of PHC on acute lung injury (ALI) induced by severe acute pancreatitis (SAP) and the expression of hypoxia-inducible factor-1α (HIF-1α) in rats. A total of 45 healthy adult male SD rats were randomly divided into 3 groups: an S group, sham operation; an ALI group, pancreatitis-associated acute lung injury (PALI); and a P group, PALI treated with PHC. Rats from the ALI and P groups were used to establish a model of acute lung injury associated with SAP by retrograde injection of 4% sodium taurocholate into the biliopancreatic duct. Rats in the P group, reflecting acute lung injury caused by SAP, were treated with PHC immediately following SAP. Rats in the S and ALI groups were injected with the same amount of 0.9% sodium chloride solution. After modeling, the rats were sacrificed at 12h. The wet/dry weight (W/D) ratios of lung tissue were calculated. Pathological changes in pancreatic and lung tissues were scored. The expression levels of TLR4 and NF-κB p65 in lung tissue were detected by Western blot. RT-PCR was used to detect HIF-1α mRNA in lung tissue. The HIF-1α, IL-1β, and IL-6 expression levels in lung tissues and serum amylase levels were detected by ELISA. The results showed extensive infiltration of neutrophils, alveolar hemorrhage and necrosis and fat necrosis in the pancreatic tissue of rats in the PALI and P groups. Their pancreatic tissue injury scores were significantly higher than the score of the S group (P<0.01). However, no statistically significant difference was observed in the serum amylase levels of the P and ALI groups (P>0.05). The W/D ratios of lung tissue in the ALI and P group rats were significantly higher than those in the S group (P<0.05). Compared with those of the ALI group rats, the lung tissue pathological changes of the P group were significantly improved, and the lung W/D value was significantly lower than that of the ALI group (P<0.05). Compared with those of the S group, the TLR4, NF-κB p65, HIF-1α mRNA, and HIF-1α expression levels in the lung tissue of the ALI and P groups were significantly higher (P<0.01), and the TLR4, NF-κB p65, HIF-1α mRNA, HIF-1α, IL-1β and IL-6 expression levels in the P group were significantly lower than those in the ALI group (P<0.05). The current work indicates that PHC could not alleviate the damage to pancreatic tissue caused by SAP. However, PHC did suppress HIF-1α, IL-1β and IL-6 expression levels and reduced the acute lung injury induced by SAP in rats, which might depend on suppression of the expression of inflammatory factors, such as HIF-1α.

Necroptosis: A Novel Cell Death Modality and Its Potential Relevance for Critical Care Medicine

Cell death is intertwined with life in development, homeostasis, pathology, and aging. Until recently, apoptosis was the best known form of programmed cell death, whereas necrosis was for a long time considered accidental owing to physicochemical injury. However, identification of crucial signaling and execution molecules, which are highly regulated, revealed that necrosis encompasses several cell death modalities that can be therapeutically targeted. The best understood form of regulated necrosis is necroptosis, which is transduced by the kinase activities of receptor interacting protein kinase-1 and receptor interacting protein kinase-3, eventually leading to the activation of mixed lineage kinase domain-like and plasma membrane permeabilization. We are only beginning to appreciate the role of necroptosis in different pathological conditions, including critical illnesses. In this review, we discuss the molecular mechanisms of necroptosis and analyze the effect of inhibiting necroptosis in experimental models of critical illnesses. In view of the identification of an increasing number of cell death modalities, we also briefly discuss the simultaneous targeting of multiple cell death modalities because, depending on the cell type and cellular conditions, various types of cell death may contribute to the pathology.

HMGB1 and Extracellular Histones Significantly Contribute to Systemic Inflammation and Multiple Organ Failure in Acute Liver Failure

Acute liver failure (ALF) is the culmination of severe liver cell injury from a variety of causes. ALF occurs when the extent of hepatocyte death exceeds the hepatic regenerative capacity. ALF has a high mortality that is associated with multiple organ failure (MOF) and sepsis; however, the underlying mechanisms are still not clear. Emerging evidence shows that ALF patients/animals have high concentrations of circulating HMGB1, which can contribute to multiple organ injuries and mediate gut bacterial translocation (BT). BT triggers/induces systemic inflammatory responses syndrome (SIRS), which can lead to MOF in ALF. Blockade of HMGB1 significantly decreases BT and improves hepatocyte regeneration in experimental acute fatal liver injury. Therefore, HMGB1 seems to be an important factor that links BT and systemic inflammation in ALF. ALF patients/animals also have high levels of circulating histones, which might be the major mediators of systemic inflammation in patients with ALF. Extracellular histones kill endothelial cells and elicit immunostimulatory effect to induce multiple organ injuries. Neutralization of histones can attenuate acute liver, lung, and brain injuries. In conclusion, HMGB1 and histones play a significant role in inducing systemic inflammation and MOF in ALF.

HMGB1 and Histones Play a Significant Role in Inducing Systemic Inflammation and Multiple Organ Dysfunctions in Severe Acute Pancreatitis

Severe acute pancreatitis (SAP) starts as a local inflammation of pancreatic tissue that induces the development of multiple extrapancreatic organs dysfunction; however, the underlying mechanisms are still not clear. Ischemia-reperfusion, circulating inflammatory cytokines, and possible bile cytokines significantly contribute to gut mucosal injury and intestinal bacterial translocation (BT) during SAP. Circulating HMGB1 level is significantly increased in SAP patients and HMGB1 is an important factor that mediates (at least partly) gut BT during SAP. Gut BT plays a critical role in triggering/inducing systemic inflammation/sepsis in critical illness, and profound systemic inflammatory response syndrome (SIRS) can lead to multiple organ dysfunction syndrome (MODS) during SAP, and systemic inflammation with multiorgan dysfunction is the cause of death in experimental SAP. Therefore, HMGB1 is an important factor that links gut BT and systemic inflammation. Furthermore, HMGB1 significantly contributes to multiple organ injuries. The SAP patients also have significantly increased circulating histones and cell-free DNAs levels, which can reflect the disease severity and contribute to multiple organ injuries in SAP. Hepatic Kupffer cells (KCs) are the predominant source of circulating inflammatory cytokines in SAP, and new evidence indicates that hepatocyte is another important source of circulating HMGB1 in SAP; therefore, treating the liver injury is important in SAP.

Chronic Pancreatitis Associated Acute Respiratory Failure

Pancreatitis is a condition characterized by parenchymal inflammation of the pancreas, which is often associated with lung injury due to low level of oxygen and the condition is termed as acute pancreatitis-associated lung injury (APALI). Clinical reports indicated that ~ 20% to 50% of patients from low oxygen levels in blood with acute respiratory distress syndrome (ARDS). ARDS is a severe form of acute lung injury (ALI), a pulmonary disease with impaired airflow making patients difficult to breathe. ALI is frequently observed in patients with severe acute pancreatitis. Approximately one third of severe pancreatitis patients develop acute lung injury and acute respiratory distress syndrome that account for 60% of all deaths within the first week. The major causes of ALI and ARDS are sepsis, trauma, aspiration, multiple blood transfusion, and most importantly acute pancreatitis. The molecular mechanisms of ALI and ARDS are still not well explored, but available reports indicate the involvement of several pro-inflammatory mediators including cytokines (TNF-α, IL-1β, IL-6) and chemokines [like interleukin-8 (IL-8) and macrophage inhibitory factor (MIF)], as well as macrophage polarization regulating the migration and pulmonary infiltration of neutrophils into the pulmonary interstitial tissue, causing injury to the pulmonary parenchyma. Acute lung injury and acute respiratory distress syndrome in acute pancreatitis remains an unsolved issue and needs more research and resources to develop effective treatments and therapies. However, recent efforts have tested several molecules in an experimental model and showed promising results as a treatment option. The current review summarized the mechanism that is operational in pancreatitis-associated acute respiratory failure and respiratory distress syndrome in patients and current treatment options.

Ethyl pyruvate is a novel anti-inflammatory agent to treat multiple inflammatory organ injuries

Ethyl pyruvate (EP) is a simple derivative of pyruvic acid, which is an important endogenous metabolite that can scavenge reactive oxygen species (ROS). Treatment with EP is able to ameliorate systemic inflammation and multiple organ dysfunctions in multiple animal models, such as acute pancreatitis, alcoholic liver injury, acute respiratory distress syndrome (ARDS), acute viral myocarditis, acute kidney injury and sepsis. Recent studies have demonstrated that prolonged treatment with EP can ameliorate experimental ulcerative colitis and slow multiple tumor growth. It has become evident that EP has pharmacological anti-inflammatory effect to inhibit multiple early inflammatory cytokines and the late inflammatory cytokine HMGB1 release, and the anti-tumor activity is likely associated with its anti-inflammatory effect. EP has been tested in human volunteers and in a clinical trial of patients undergoing cardiac surgery in USA and shown to be safe at clinical relevant doses, even though EP fails to improve outcome of the heart surgery, EP is still a promising agent to treat patients with multiple inflammatory organ injuries and the other clinical trials are on the way. This review focuses on how EP is able to ameliorate multiple organ injuries and summarize recently published EP investigations.

Graphical Abstract

Stimulation of Central α2 Receptors Attenuates Experimental Necrotizing Pancreatitis

OBJECTIVES

Severe necrotizing pancreatitis (SNP) is a disease with relevant morbidity and mortality until today. No specific therapy is in sight. Central α2 agonists such as clonidine and dexmedetomidine are known to have anti-inflammatory effects though the cholinergic anti-inflammatory pathway and are implemented in the clinical routine as adjunct sedative drugs. Their potential effect on SNP has not yet been tested.

METHODS

Severe necrotizing pancreatitis was induced in male Wistar rats. Four treatment groups received either clonidine or dexmedetomidine before (prophylactic) or after induction of SNP (therapeutic). After 12 hours, pancreatic morphologic injury, systemic proinflammatory high-mobility group box 1 protein, and pancreatic and pulmonary myeloperoxidase levels were evaluated.

RESULTS

Severe necrotizing pancreatitis was fully established 12 hours after induction. "Prophylactic" and "therapeutic" administration of clonidine and dexmedetomidine reduced pancreatic morphologic injury (P < 0.05 vs SNP), serum proinflammatory high-mobility group box 1 protein (P < 0.0001 vs SNP), as well as pancreatic and pulmonary myeloperoxidase levels (P < 0.01 vs SNP).

CONCLUSIONS

Prophylactic and therapeutic applications of the central α2 agonists clonidine and dexmedetomidine are effective to attenuate local and systemic injury in experimental SNP and should be evaluated in the clinical setting.

TLR4-mediated NF-κB signaling pathway mediates HMGB1-induced pancreatic injury in mice with severe acute pancreatitis

Severe acute pancreatitis (SAP) is an extremely dangerous acute abdominal disorder which causes multiple complications and has a high mortality rate. Previous research has suggested that high-mobility group box 1 (HMGB1) plays an important role in the pathogenesis of SAP; however, the mechanisms underlying this strong correlation remain unclear. In this study, to further investigate whether HMGB1 acts as a stimulating factor, and whether Toll-like receptor 4 (TLR4) acts as its major mediator in the development of pancreatic injury during SAP, recombinant human HMGB1 (rhHMGB1) and TLR4-deficient mice were used. We found that HMGB1 and TLR4 were highly expressed, and nuclear factor-κB (NF-κB) was activated in our mouse model of SAP. We noted that the rhHMGB1 pancreas-targeted injection activated the TLR4-mediated NF-κB signaling pathway and induced pancreatic injury in wild-type mice. In TLR4-deficient mice, the rhHMGB1-induced activation of NF-κB and pathological changes in the pancreas were less evident than in wild-type mice. Therefore, this study provides evidence that HMGB1 promotes the pathogenesis of pancreatitis, and its downstream TLR4-mediated NF-κB signaling pathway is a potential important mediator in the development of this form of pancreatic injury.

Sodium Butyrate Reduces Organ Injuries in Mice with Severe Acute Pancreatitis Through Inhibiting HMGB1 Expression

OBJECTIVE

The present study was designed to evaluate the effect of sodium butyrate on pancreas damage and to investigate the role of high-mobility group box-1 (HMGB1) and nuclear factor-κB (NF-κB) in the development of severe acute pancreatitis (SAP) in a mouse model.

METHODS

The SAP model was established by intraperitoneal injection of two doses of 20 % L-2 arginine (200 mg/g). Female Sprague-Dawley mice were randomly allocated into three groups (n = 48/group): the control, untreated SAP, and sodium butyrate-treated SAP groups. The animals were euthanized at 0, 12, 24, and 48 h after the establishment of the SAP. Histopathology of the pancreas was performed, and the NF-κB levels were determined by immunohistochemistry. The serum levels of tumor necrosis factor (TNFα), interleukin-6 (IL-6), and HMGB1 were measured by ELISA. The HMGB1 mRNA levels were determined by qRT-PCR.

RESULTS

The sodium butyrate-treated SAP animals showed significantly improved pancreas histopathology and lower serum amylase levels than the untreated SAP animals. In the SAP group, the mRNA levels of HMGB1 were remarkably increased at the 12 h, peaked at 24 h, and remained at a high level up to 48 h after L-2 arginine injection. The levels of TNFα and IL-6 were decreased at 48 h. Treatment with sodium butyrate reduced the pathological lesions, the serum levels of HMGB1, TNFα, and IL-6, the HMGB1 mRNA levels, and NF-κB activity.

CONCLUSION

Sodium butyrate inhibits the NF-κB activation and reduces pancreas injury in SAP through the modulation of HMGB1 and other inflammatory cytokine responses.

Inflammatory profiling of early experimental necrotizing pancreatitis

AIMS

Inflammatory mediators play a pivotal role in severe necrotizing pancreatitis (SNP). Therapeutic approaches aim at the early inflammatory liberation of cytokines to avoid systemic complications. The present study evaluates the kinetics of inflammatory mediator release in SNP.

MAIN METHODS

Experimental SNP was induced in male Wistar rats using the GDOC model. The animals were allocated into seven groups (n = 6/group). In group 1, sample harvesting was performed after sham operation while in groups 2-7 this was performed 1 h, 2 h, 4 h, 6 h, 9 h, and 12 h after initiation of SNP, respectively. Inflammatory mediator release,morphologic injury, and tissue MPO concentrations were evaluated between 1 and 12 h after induction.

KEY FINDINGS

Pancreatic injury showed a continuous increase over the observation period (p b 0.05, respectively). MPO levels in the pancreas and lungs increased until 12 h after induction (p b 0.05, respectively). Antiinflammatory IL-10 showed an early peak and the pro-inflammatory mediators TNFα and IL-1β peaked after 6 and 9 h, respectively (p b 0.05, respectively). HMGB1 levels constantly increased over time (p b 0.05, respectively).

SIGNIFICANCE

The present study shows the release of relevant pro- and anti-inflammatory mediators in SNP for the first time in one single experimental setup. Inflammatory mediators peak within the first few hours after SNP induction. Consequently, the effect of therapeutic approaches on early changes in cytokine release should be evaluated later than 2 h after initiation.

High-mobility group box 1 protein and its role in severe acute pancreatitis

The high mobility group box 1 (HMGB1), which belongs to the subfamily of HMG-1/-2, is a highly conserved single peptide chain consisting of 215 amino acid residues with a molecular weight of approximately 24894 Da. HMGB1 is a ubiquitous nuclear protein in mammals and plays a vital role in inflammatory diseases. Acute pancreatitis is one of the most common causes of acute abdominal pain with a poor prognosis. Acute pancreatitis is an acute inflammatory process of the pancreas (duration of less than six months), for which the severe form is called severe acute pancreatitis (SAP). More and more studies have shown that HMGB1 has a bidirectional effect in the pathogenesis of SAP. Extracellular HMGB1 can aggravate the pancreatic inflammatory process, whereas intracellular HMGB1 has a protective effect against pancreatitis. The mechanism of HMGB1 is multiple, mainly through the nuclear factor-κB pathway. Receptors for advanced glycation end-products and toll-like receptors (TLR), especially TLR-2 and TLR-4, are two major types of receptors mediating the inflammatory process triggered by HMGB1 and may be also the main mediators in the pathogenesis of SAP. HMGB1 inhibitors, such as ethyl pyruvate, pyrrolidine dithiocarbamate and Scolopendra subspinipes mutilans, can decrease the level of extracellular HMGB1 and are the promising targets in the treatment of SAP.

Correlation between serum levels of high mobility group box-1 protein and pancreatitis: a meta-analysis

Background. Aberrant expression of high mobility group box-1 protein (HMGB1) contributes to the progression of various inflammatory diseases. This meta-analysis focused on the clinical significance of serum HMGB1 levels in pancreatitis patients, with the goal of building a novel diagnostic score model. Method. We conducted a meta-analysis by searching in the PubMed, Embase, Web of Science, Cochrane Library, CISCOM, CINAHL, Google Scholar, China BioMedicine (CBM), and China National Knowledge Infrastructure (CNKI) databases without any language restrictions. Studies were pooled and standard mean difference (SMD) and its corresponding 95% confidence intervals (95% CIs) were calculated. Version 12.0 STATA software was used for statistical analysis. Results. We performed a final analysis of 841 subjects from 12 clinical case-control studies. The meta-analysis results showed a positive association between serum HMGB1 levels and the progression of pancreatitis. In the subgroup analysis by country, high serum level of HMGB1 may be related to pancreatitis progression in China, Korea, Hungary, and Japan populations (all P < 0.05). Conclusion. The present meta-analysis indicated that serum HMGB1 level was statistically elevated in patients with pancreatitis, and thus serum levels of HMGB1 could be determined to be a useful biomarker for pancreatitis patients.

Downregulation of high mobility group box 1 attenuates the severity of acute lung injury in endotoxemic mice

High mobility group box 1 (HMGB1) is a systemic inflammation‑associated cytokine mediator. The aim of the present study was to examine the effect of the downregulation of HMGB1 in a lipopolysaccharide (LPS)‑induced mouse model of acute lung injury (ALI). It was identified that serum levels of tumor necrosis factor‑α and interleukin‑1β, lung myeloperoxidase activity and malondialdehyde content, as well as lung wet/dry weight ratios were all increased following LPS challenge. However, LPS‑mediated increases in these parameters were significantly downregulated in HMGB1 small interfering (si)RNA‑treated mice versus the negative control siRNA‑treated mice. In addition, the administration of HMGB1 siRNA in LPS‑treated mice resulted in a decreased DNA binding activity of nuclear factor‑κB (NF‑κB) in the lung. It was demonstrated that downregulation of HMGB1 decreases inflammation and the severity of sepsis associated with ALI, possibly via inhibiting the NF‑κB DNA‑binding activity. The present data support HMGB1 as a contributor to the pathogenesis of LPS‑induced sepsis and ALI.