Accuracy of circulating histones in predicting persistent organ failure and mortality in patients with acute pancreatitis

Influencing factor analysis and clinical efficacy of early intervention in severe acute pancreatitis with persistent organ failure

This study aims to analyze the risk factors requiring early intervention in severe acute pancreatitis (SAP) patients with persistent organ failure and evaluate the clinical outcomes following treatment. This was a retrospective observational study. Inverse probability treatment weighting using propensity score methods was employed to balance baseline characteristics. Univariate and multivariate logistic regression analyses were performed to identify risk factors associated with early intervention. Smooth curve fitting was applied to explore potential relationships between variables and intervention timing. Threshold effect analysis was conducted to identify the optimal inflection point in nonlinear relationship. A total of 310 patients were included in this study. Compared to the standard treatment group (n = 162), the early intervention group (n = 148) had a higher proportion of multiple organ failure (77.1% vs. 63.6%, P = 0.021) and higher mortality (27.7% vs. 16.0%, P = 0.013), but early intervention was not significantly associated with adverse outcome (OR 1.52, 95% CI 0.71-3.26, P = 0.283). Risk factors associated with early intervention included computed tomography severity index, SOFA score, intra-abdominal pressure (IAP), and remifentanil equivalents. Among these, the SOFA score showed a negative linear relationship with intervention timing, while distinct threshold effects were observed between IAP, remifentanil equivalents, and intervention timing. One week after intervention, most patients showed improved organ function, along with reduced requirements for sedation and analgesia, as well as decreased C-reactive protein level levels and IAP (all P < 0.05). SAP patients requiring early intervention tended to have higher disease severity. Although early intervention can improve short-term organ function, reduce IAP, and lower analgesic requirements, its impact on reducing mortality remains uncertain.

Histones are critical toxic factors in gut lymph of severe acute pancreatitis: Neutralization by baicalin and baicalein for protection

BACKGROUND

Whether circulating histones in gut lymph contribute to organ failure and impact of chaiqin chengqi decoction (CQCQD) on histones in severe acute pancreatitis (SAP) remain elusive.

PURPOSE

To verify the role of histones in gut lymph of SAP and evaluate the effect of the CQCQD on them.

METHODS

Sodium taurocholate was retrogradely infused into pancreatobiliary duct to induce SAP in rodents. Various regimens of CQCQD were administered intragastrically or via duodenum followed by dynamic gut lymph collection in rats. The impact of gut lymph and histones on endothelial cell viability and lymphocytes was determined. Components of CQCQD in gut lymph were identified by UHPLC-MS and their binding activities with histones were quantified by biolayer interferometry followed by validation in vitro and in vivo in mice.

RESULTS

The histone level was significantly increased in gut lymph of SAP at various time points assessed, closely correlating with multiple organ injury (MOI) indices and contemporary cell viability. Inhibition of histones reduced cytotoxicity induced by SAP-conditioned gut lymph. CQCQD reduced apoptotic cell death in mesenteric lymph nodes, histone level, and cytotoxicity of gut lymph, alleviating MOI parameters. Baicalin and baicalein were amongst top 13 identified CQCQD components absorbed into gut lymph to actively bind histones, block membrane disruption and calcium influx of lymphocytes, and inhibit their cytotoxicity. Both baicalin and baicalein mitigated histone- and SAP-induced MOI indices in mice.

CONCLUSION

Histones are key toxic factors in the gut lymph of SAP and their antagonism by baicalin and baicalein offers a novel therapeutic strategy.

Hemocompatible nucleosome-inspired heparin-mimicking hydrogel microspheres for safe and efficient extracorporeal removal of circulating histones in critically ill patients

Circulating histones have been identified as essential mediators that lead to hyperinflammation, platelet aggregation, coagulation cascade activation, endothelial cell injury, multiple organ dysfunction, and death in severe patients with sepsis, multiple trauma, COVID-19, acute liver failure, and pancreatitis. Clinical evidence suggests that plasma levels of circulating histones are positively associated with disease severity and survival in patients with such critical diseases. However, safe and efficient therapeutic strategies targeting circulating histones are lacking in current clinical practice. Extracorporeal blood purification, a widely used life support technique in intensive care units, is a promising therapeutic option for eliminating circulating histones. Inspired by electrostatic interactions between DNA chains and histones in natural nucleosomes, we propose a "one stone kills two birds" strategy to combat histone-related critical diseases by developing heparin-mimicking hydrogel microspheres (RCHMs). On one hand, the heparin-mimicking hydrogel structure inside RCHMs contains a large number of carboxyl and sulphonic acid groups by in situ cross-linking polymerization, which endows the RCHMs with excellent hemocompatibility. On the other hand, the RCHMs can adsorb circulating histones through electrostatic interactions. Our results demonstrate that the RCHMs do not cause significant hemolysis, blood cell activation and complement activation, with improved anti-protein contamination properties. The tailored RCHM microspheres (A3M1) can efficiently and selectively adsorb 91.16% of calf thymus histones with an adsorption capacity of 20.47 μg mg-1 within 4 h. Moreover, the RCHMs significantly attenuate histone-mediated thrombocytopenia, platelet aggregation, and endothelial cell death. Therefore, the RCHMs are promising hemoperfusion adsorbents for extracorporeal removal of circulating histones from the blood of critically ill patients, providing a new insight into the management of multiple histone-related disorders.

Coagulopathy and acute pancreatitis: pathophysiology and clinical treatment

Coagulopathy is a critical pathophysiological mechanism of acute pancreatitis (AP), arising from the complex interplay between innate immune, endothelial cells and platelets. Although initially beneficial for the host, uncontrolled and systemic activation of coagulation cascade in AP can lead to thrombotic and hemorrhagic complications, ranging from subclinical abnormalities in coagulation tests to severe clinical manifestations, such as disseminated intravascular coagulation. Initiation of coagulation activation and consequent thrombin generation is caused by expression of tissue factor on activated monocytes and is ineffectually offset by tissue factor pathway inhibitor. At the same time, endothelial-associated anticoagulant pathways, in particular the protein C system, is impaired by pro-inflammatory cytokines. Also, fibrin removal is severely obstructed by inactivation of the endogenous fibrinolytic system, mainly as a result of upregulation of its principal inhibitor, plasminogen activator inhibitor type 1. Finally, increased fibrin generation and impaired break down lead to deposition of (micro) vascular clots, which may contribute to tissue ischemia and ensuing organ dysfunction. Despite the high burden of coagulopathy that have a negative impact on AP patients' prognosis, there is no effective treatment yet. Although a variety of anticoagulants drugs have been evaluated in clinical trials, their beneficial effects are inconsistent, and they are also characterized by hemorrhagic complications. Future studies are called to unravel the pathophysiologic mechanisms involved in coagulopathy in AP, and to test novel therapeutics block coagulopathy in AP.

Fibrinogen binding to histones in circulation protects against adverse cellular and clinical outcomes

BACKGROUND

Circulating histones are released by extensive tissue injury or cell death and play important pathogenic roles in critical illnesses. Their interaction with circulating plasma components and the potential roles in the clinical setting are not fully understood.

OBJECTIVES

We aimed to characterize the interaction of histones with fibrinogen and explore its roles in vitro, in vivo, and in patient samples.

METHODS

Histone-fibrinogen binding was assessed by electrophoresis and enzyme-linked immunosorbent assay-based affinity assay. Functional significance was explored using washed platelets and endothelial cells in vitro and histone-infusion mouse models in vivo. To determine clinical translatability, a retrospective single-center cohort study was conducted on patients requiring intensive care admission (n = 199) and validated in a cohort of hospitalized patients with COVID-19 (n = 69).

RESULTS

Fibrinogen binds histones through its D-domain with high affinity (calf thymus histones, KD = 18.0 ± 5.6 nM; histone 3, KD = 2.7 ± 0.8 nM; and histone 4, KD = 2.0 ± 0.7 nM) and significantly reduces histone-induced endothelial damage and platelet aggregation in vitro and in vivo in a histone-infusion mouse model. Physiologic concentrations of fibrinogen can neutralize low levels of circulating histones and increase the cytotoxicity threshold of histones to 50 μg/mL. In a cohort of patients requiring intensive care, a histone:fibrinogen ratio of ≥6 on admission was associated with moderate-severe thrombocytopenia and independently predicted mortality. This finding was validated in a cohort of hospitalized patients with COVID-19.

CONCLUSION

Fibrinogen buffers the cytotoxic properties of circulating histones. Detection and monitoring of circulating histones and histone:fibrinogen ratios will help identify critically ill patients at highest risk of adverse outcomes who might benefit from antihistone therapy.

A dose-response correlation between smoking and severity of acute pancreatitis: a propensity score-matched study

Background

Acute pancreatitis, among the most prevalent gastrointestinal disorders, exhibits a continual rise in its incidence recent years. This study endeavor to explore the correlation between smoking exposure and the severity of acute pancreatitis (AP).

Methods

Five hundred and eight patients diagnosed as acute pancreatitis (AP) were included in our data analysis. Patients were categorized based on their smoking pack-years into four groups: light, moderate, heavy, and non-smokers. Outcomes were classified as two: "mild acute pancreatitis (MAP)" and "moderately severe acute pancreatitis (MSAP) or severe acute pancreatitis (SAP)". We conducted propensity score matching (PSM) to adjust confounding factors and multivariable logistic regression analysis to determine adjusted odds ratios and 95% confidence intervals. Additionally, a dose-dependent association analysis between smoking exposure and the incidence rate of "MSAP or SAP" was performed.

Results

Smokers exhibited a higher risk of "MSAP or SAP" compared to non-smokers, both before (17.1 vs. 54.9%, p < 0.001) and after (9.4 vs. 24.7%, p < 0.001) PSM. With an area under the ROC curve of 0.708, smoking showed a moderate level of predictive ability. Furthermore, propensity score matching analysis showed that patients who smoked compared to non-smokers had significantly higher risks of "MSAP or SAP" for light smoking (OR 3.76, 95% CI 1.40-10.07, p = 0.008), moderate smoking (OR 4.94, 95% CI 2.23-10.92, p < 0.001), and heavy smoking (OR 8.08, 95% CI 3.39-19.25, p < 0.001).

Conclusion

Smoking is an independent risk factor that can raise the severity of pancreatitis. Moreover, the severity of acute pancreatitis escalates in tandem with the accumulation of pack-years of smoking.

Early Predictive Value of Different Indicators for Persistent Organ Failure in Acute Pancreatitis: A Systematic Review and Network Meta-Analysis

GOALS

In this study, we conducted this network meta-analysis (based on the ANOVA model) to evaluate the predictive efficacy of each early predictor.

BACKGROUND

Persistent organ failure (POF) is one of the determining factors in patients with acute pancreatitis (AP); however, the diagnosis of POF has a long-time lag (>48 h). It is of great clinical significance for the early noninvasive prediction of POF.

STUDY

We conducted a comprehensive and systematic search in PubMed, Cochrane library, Embase, and Web of Science to identify relevant clinical trials, case-control studies, or cohort studies, extracted the early indicators of POF in studies, and summarized the predictive efficacy of each indicator through network meta-analysis. The diagnostic odds ratio (DOR) was used to rank the prediction efficiency of each indicator.

RESULTS

We identified 23 studies in this network meta-analysis, including 10,393 patients with AP, of which 2014 patients had POF. A total of 10 early prediction indicators were extracted. The mean and 95% CI lower limit of each predictive indicator were greater than 1.0. Albumin had the largest diagnostic odds ratio, followed by high-density lipoprotein-cholesterol (HDL-C), Ranson Score, beside index for severity in acute pancreatitis Score, acute physiology and chronic health evaluation II, C-reactive protein (CRP), Interleukin 6 (IL-6), Interleukin 8 (IL-8), Systemic Inflammatory Response Syndrome (SIRS) and blood urea nitrogen.

CONCLUSIONS

Albumin, high-density lipoprotein-cholesterol, Ranson Score, and beside index for severity in acute pancreatitis Score are effective in the early prediction of POF in patients with AP, which can provide evidence for developing effective prediction systems. However, due to the limitations of the extraction method of predictive indicators in this study, some effective indicators may not be included in this meta-analysis.

Cell-free histones and the cell-based model of coagulation

The cell-based model of coagulation remains the basis of our current understanding of clinical hemostasis and thrombosis. Its advancement on the coagulation cascade model has enabled new prohemostatic and anticoagulant treatments to be developed. In the past decade, there has been increasing evidence of the procoagulant properties of extracellular, cell-free histones (CFHs). Although high levels of circulating CFHs released following extensive cell death in acute critical illnesses, such as sepsis and trauma, have been associated with adverse coagulation outcomes, including disseminated intravascular coagulation, new information has also emerged on how its local effects contribute to physiological clot formation. CFHs initiate coagulation by tissue factor exposure, either by destruction of the endovascular barrier or induction of endoluminal tissue factor expression on endothelia and monocytes. CFHs can also bind prothrombin directly, generating thrombin via the alternative prothrombinase pathway. In amplifying and augmenting the procoagulant signal, CFHs activate and aggregate platelets, increase procoagulant material bioavailability through platelet degranulation and Weibel-Palade body exocytosis, activate intrinsic coagulation via platelet polyphosphate release, and induce phosphatidylserine exposure. CFHs also inhibit protein C activation and downregulate thrombomodulin expression to reduce anti-inflammatory and anticoagulant effects. In consolidating clot formation, CFHs augment the fibrin polymer to confer fibrinolytic resistance and integrate neutrophil extracellular traps into the clot structure. Such new information holds the promise of new therapeutic developments, including improved targeting of immunothrombotic pathologies in acute critical illnesses.

Validation of circulating histone detection by mass spectrometry for early diagnosis, prognosis, and management of critically ill septic patients

BACKGROUND

As leading contributors to worldwide morbidity and mortality, sepsis and septic shock are considered a major global health concern. Proactive biomarker identification in patients with sepsis suspicion at any time remains a daunting challenge for hospitals. Despite great progress in the understanding of clinical and molecular aspects of sepsis, its definition, diagnosis, and treatment remain challenging, highlighting a need for new biomarkers with potential to improve critically ill patient management. In this study we validate a quantitative mass spectrometry method to measure circulating histone levels in plasma samples for the diagnosis and prognosis of sepsis and septic shock patients.

METHODS

We used the mass spectrometry technique of multiple reaction monitoring to quantify circulating histones H2B and H3 in plasma from a monocenter cohort of critically ill patients admitted to an Intensive Care Unit (ICU) and evaluated its performance for the diagnosis and prognosis of sepsis and septic shock (SS).

RESULTS

Our results highlight the potential of our test for early diagnosis of sepsis and SS. H2B levels above 121.40 ng/mL (IQR 446.70) were indicative of SS. The value of blood circulating histones to identify a subset of SS patients in a more severe stage with associated organ failure was also tested, revealing circulating levels of histones H2B above 435.61 ng/ml (IQR 2407.10) and H3 above 300.61 ng/ml (IQR 912.77) in septic shock patients with organ failure requiring invasive organ support therapies. Importantly, we found levels of H2B and H3 above 400.44 ng/mL (IQR 1335.54) and 258.25 (IQR 470.44), respectively in those patients who debut with disseminated intravascular coagulation (DIC). Finally, a receiver operating characteristic curve (ROC curve) demonstrated the prognostic value of circulating histone H3 to predict fatal outcomes and found for histone H3 an area under the curve (AUC) of 0.720 (CI 0.546-0.895) p < 0.016 on a positive test cut-off point at 486.84 ng/mL, showing a sensitivity of 66.7% and specificity of 73.9%.

CONCLUSIONS

Circulating histones analyzed by MS can be used to diagnose SS and identify patients at high risk of suffering DIC and fatal outcome.

Targeting circulating high mobility group box-1 and histones by extracorporeal blood purification as an immunomodulation strategy against critical illnesses

Both high mobility group box-1 (HMGB1) and histones are major damage-associated molecular patterns (DAPMs) that mediate lethal systemic inflammation, activation of the complement and coagulation system, endothelial injury and multiple organ dysfunction syndrome in critical illnesses. Although accumulating evidence collectively shows that targeting HMGB1 or histones by their specific antibodies or inhibitors could significantly mitigate aberrant immune responses in multiple critically ill animal models, routine clinical use of such agents is still not recommended by any guideline. In contrast, extracorporeal blood purification, which has been widely used to replace dysfunctional organs and remove exogenous or endogenous toxins in intensive care units, may also exert an immunomodulatory effect by eliminating inflammatory mediators such as cytokines, endotoxin, HMGB1 and histones in patients with critical illnesses. In this review, we summarize the multiple immunopathological roles of HMGB1 and histones in mediating inflammation, immune thrombosis and organ dysfunction and discuss the rationale for the removal of these DAMPs using various hemofilters. The latest preclinical and clinical evidence for the use of extracorporeal blood purification to improve the clinical outcome of critically ill patients by targeting circulating HMGB1 and histones is also gathered.

Predicting Persistent Acute Respiratory Failure in Acute Pancreatitis: The Accuracy of Two Lung Injury Indices

BACKGROUND/AIMS

Early and accurate identification of patients with acute pancreatitis (AP) at high risk of persistent acute respiratory failure (PARF) is crucial. We sought to determine the accuracy of simplified Lung Injury Prediction Score (sLIPS) and simplified Early Acute Lung Injury (sEALI) for predicting PARF in ward AP patients.

METHODS

Consecutive AP patients in a training cohort from West China Hospital of Sichuan University (n = 912) and a validation cohort from The First Affiliated Hospital of Nanchang University (n = 1033) were analyzed. PARF was defined as oxygen in arterial blood/fraction of inspired oxygen < 300 mmHg that lasts for > 48 h. The sLIPS was composed by shock (predisposing condition), alcohol abuse, obesity, high respiratory rate, low oxygen saturation, high oxygen requirement, hypoalbuminemia, and acidosis (risk modifiers). The sEALI was calculated from oxygen 2 to 6 L/min, oxygen > 6 L/min, and high respiratory rate. Both indices were calculated on admission.

RESULTS

PARF developed in 16% (145/912) and 22% (228/1033) (22%) of the training and validation cohorts, respectively. In these patients, sLIPS and sEALI were significantly increased. sLIPS ≥ 2 predicted PARF in the training (AUROC 0.87, 95% CI 0.84-0.89) and validation (AUROC 0.81, 95% CI 0.78-0.83) cohorts. sLIPS was significantly more accurate than sEALI and current clinical scoring systems in both cohorts (all P < 0.05).

CONCLUSIONS

Using routinely available clinical data, the sLIPS can accurately predict PARF in ward AP patients and outperforms the sEALI and current existing clinical scoring systems.

Fire in the belly: A scoping review of the immunopathological mechanisms of acute pancreatitis

Introduction

Acute pancreatitis (AP) is characterised by an inflammatory response that in its most severe form can cause a systemic dysregulated immune response and progression to acute multi-organ dysfunction. The pathobiology of the disease is unclear and as a result no targeted, disease-modifying therapies exist. We performed a scoping review of data pertaining to the human immunology of AP to summarise the current field and to identify future research opportunities.

Methods

A scoping review of all clinical studies of AP immunology was performed across multiple databases. Studies were included if they were human studies of AP with an immunological outcome or intervention.

Results

205 studies met the inclusion criteria for the review. Severe AP is characterised by significant immune dysregulation compared to the milder form of the disease. Broadly, this immune dysfunction was categorised into: innate immune responses (including profound release of damage-associated molecular patterns and heightened activity of pattern recognition receptors), cytokine profile dysregulation (particularly IL-1, 6, 10 and TNF-α), lymphocyte abnormalities, paradoxical immunosuppression (including HLA-DR suppression and increased co-inhibitory molecule expression), and failure of the intestinal barrier function. Studies including interventions were also included. Several limitations in the existing literature have been identified; consolidation and consistency across studies is required if progress is to be made in our understanding of this disease.

Conclusions

AP, particularly the more severe spectrum of the disease, is characterised by a multifaceted immune response that drives tissue injury and contributes to the associated morbidity and mortality. Significant work is required to develop our understanding of the immunopathology of this disease if disease-modifying therapies are to be established.

Hemorheological and Microcirculatory Relations of Acute Pancreatitis

Acute pancreatitis still means a serious challenge in clinical practice. Its pathomechanism is complex and has yet to be fully elucidated. Rheological properties of blood play an important role in tissue perfusion and show non-specific changes in acute pancreatitis. An increase in blood and plasma viscosity, impairment of red blood cell deformability, and enhanced red blood cell aggregation caused by metabolic, inflammatory, free radical-related changes and mechanical stress contribute to the deterioration of the blood flow in the large vessels and also in the microcirculation. Revealing the significance of these changes in acute pancreatitis may better explain the pathogenesis and optimize the therapy. In this review, we give an overview of the role of impaired microcirculation by changes in hemorheological properties in acute pancreatitis.

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.

Serum level of total histone 3, H3K4me3, and H3K27ac after non-emergent cardiac surgery suggests the persistence of smoldering inflammation at 3 months in an adult population

Background

Despite clinical relevance of immunological activation due to histone leakage into the serum following cardiac surgery, long-term data describing their longitudinal dynamic are lacking. Therefore, this study examines the serum levels of histone 3 (tH3) and its modifications (H3K4me3 and H3K27ac) alongside immune system activation during the acute and convalescence phases of cardiac surgery.

Methods

Blood samples from fifty-nine individuals were collected before non-emergent cardiac surgery (t_pre-op) and 24 h (t_24hr), seven days (t_7d), and three months (t_3m) post-procedure to examine serum levels of tH3, H3K4me3, and H3K27ac. Serum heat shock protein-60 (HSP-60) was a surrogate of the cellular damage marker. Serum C-reactive protein (CRP) and interleukin 6 (IL-6) assessed smoldering inflammation. TNFα and IL-6 production by whole blood in response to lipopolysaccharide (LPS) evaluated immunological activation. Electronic medical records provided demographic, peri-operative, and clinical information. Paired longitudinal analyses were employed with data expressed as mean and standard deviation (X ± SD) or median and interquartile range (Me[IQ25; 75%].

Results

Compared to pre-operative levels (tH3_Pre-op = 1.6[0.33;2.4]), post-operative serum tH3 significantly (p > 0.0001) increased after heart surgery (tH3_24hr = 2.2[0.3;28]), remained elevated at 7 days (tH3_7d = 2.4[0.37;5.3]), and at 3 months (tH3_3m = 2.0[0.31;2.9]). Serum H3K27ac was elevated at 24 h (H3K27ac_24hr = 0.66 ± 0.51; p = 0.025) and seven days (H3K27ac_7d = 0.94 ± 0.95; p = 0.032) as compared to baseline hours (H3K27ac_Pre-op = 0.55 ± 0.54). Serum H3K4me3 was significantly diminished at three months (H3K4me3_Pre-op = 0.94 ± 0.54 vs. H3K27ac_3m = 0.59 ± 0.89; p = 0.008). tH3 correlated significantly with the duration of anesthesia (r² = 0.38). In contrast, HSP-60 normalized seven days after surgery. Peri-operative intake of acetaminophen, but no acetylsalicylic acid (ASA), acid, ketorolac or steroids, resulted in the significant depression of serum H3K4me3 at 24 h (H3K4me3_acetom- = 1.26[0.71; 3.21] vs H3K4me3_acetom+ = 0.54[0.07;1.01]; W[50] = 2.26; p = 0.021). CRP, but not IL-6, remained elevated at 3 months compared to pre-surgical levels and correlated with tH3_24hrs (r² = 0.43), tH3_7d (r² = 0.71; p < 0.05), H3K4me3_7d (r² = 0.53), and H3K27ac_7d (r² = 0.49). Production of TNFα by whole blood in response to LPS was associated with serum tH3_24hrs (r² = 0.67). Diminished H3K4me3_24hrs, H3K27ac_24hrs, and H3K27ac_3m, accompanied the emergence of liver failure.

Conclusions

We demonstrated a prolonged elevation in serum histone 3 three months after cardiac surgery. Furthermore, histone 3 modifications had a discrete time evolution indicating differential immune activation.

Elevated serum ferritin levels are associated with severity and prognosis of severe acute pancreatitis: a preliminary cohort study

Background

Serum ferritin (SF), as an acute-phase response protein, is used to reflect the degree of oxidative stress and systemic inflammatory responses. This study was designed to assess the effect of elevated SF levels on the severity of acute pancreatitis (AP).

Methods

From January 2013 to December 2020, 200 consecutive patients with AP were retrospectively reviewed to analyze the relationships among the etiologies of pancreatitis, the severity of the disease and SF levels. The receiver operating characteristic (ROC) curve and logistic regression analysis were used to assess whether elevated SF levels could predict the onset of organ failure in AP.

Results

92 (46%) had high SF levels (> 275 ng/ml). SF levels were not associated with the etiology of AP disease. Among patients with high SF levels, there was a significant increase in the proportion of patients with severe AP (23.1% vs. 76.9%) and a higher proportion of systemic inflammatory response scores (25.9% vs. 44.6%) in comparison to patients with normal SF levels. The area under the ROC curve for SF in predicting persistent organ failure was 0.812 [95% confidence interval 0.721–0.904].

Conclusions

F concentrations were positively correlated with the severity of AP, and quantitative assessment of SF can predict disease severity and organ failure in patients with AP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02446-z.

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.

Predicting the Need for Therapeutic Intervention and Mortality in Acute Pancreatitis: A Two-Center International Study Using Machine Learning

Background: Current approaches to predicting intervention needs and mortality have reached 65–85% accuracy, which falls below clinical decision-making requirements in patients with acute pancreatitis (AP). We aimed to accurately predict therapeutic intervention needs and mortality on admission, in AP patients, using machine learning (ML). Methods: Data were obtained from three databases of patients admitted with AP: one retrospective (Chengdu) and two prospective (Liverpool and Chengdu) databases. Intervention and mortality differences, as well as potential predictors, were investigated. Univariate analysis was conducted, followed by a random forest ML algorithm used in multivariate analysis, to identify predictors. The ML performance matrix was applied to evaluate the model’s performance. Results: Three datasets of 2846 patients included 25 potential clinical predictors in the univariate analysis. The top ten identified predictors were obtained by ML models, for predicting interventions and mortality, from the training dataset. The prediction of interventions includes death in non-intervention patients, validated with high accuracy (96%/98%), the area under the receiver-operating-characteristic curve (0.90/0.98), and positive likelihood ratios (22.3/69.8), respectively. The post-test probabilities in the test set were 55.4% and 71.6%, respectively, which were considerably superior to existing prognostic scores. The ML model, for predicting mortality in intervention patients, performed better or equally with prognostic scores. Conclusions: ML, using admission clinical predictors, can accurately predict therapeutic interventions and mortality in patients with AP.

A microRNA checkpoint for Ca2+ signaling and overload in acute pancreatitis

Acute pancreatitis (AP) is a common digestive disease without specific treatment, and its pathogenesis features multiple deleterious amplification loops dependent on translation, triggered by cytosolic Ca2+ ([Ca2+]i) overload; however, the underlying mechanisms in Ca2+ overload of AP remains incompletely understood. Here we show that microRNA-26a (miR-26a) inhibits pancreatic acinar cell (PAC) store-operated Ca2+ entry (SOCE) channel expression, Ca2+ overload, and AP. We find that major SOCE channels are post-transcriptionally induced in PACs during AP, whereas miR-26a expression is reduced in experimental and human AP and correlated with AP severity. Mechanistically, miR-26a simultaneously targets Trpc3 and Trpc6 SOCE channels and attenuates physiological oscillations and pathological elevations of [Ca2+]i in PACs. MiR-26a deficiency increases SOCE channel expression and [Ca2+]i overload, and significantly exacerbates AP. Conversely, global or PAC-specific overexpression of miR-26a in mice ameliorates pancreatic edema, neutrophil infiltration, acinar necrosis, and systemic inflammation, accompanied with remarkable improvements on pathological determinants related with [Ca2+]i overload. Moreover, pancreatic or systemic administration of an miR-26a mimic to mice significantly alleviates experimental AP. These findings reveal a previously unknown mechanism underlying AP pathogenesis, establish a critical role for miR-26a in Ca2+ signaling in the exocrine pancreas, and identify a potential target for the treatment of AP.

Extracellular histones cause intestinal epithelium injury and disrupt its barrier function in vitro and in vivo

Extracellular histones are cytotoxic to various cells and have been extensively proven a vital mediator of multiple organ injuries. However, the effect of extracellular histones on the intestine remains largely unknown. This study aimed to clarify the effect of extracellular histones on the intestine. IEC-6, a cell line of rat small intestinal epithelial crypt, and C57BL/6 or ICR mice were treated with histones. The IEC-6 cells treated with histones from 20 μg/mL to 200 μg/mL for 0-24 h displayed a decline of cell viability and an increase of cell death in a concentration- and time-dependent manner. Moreover, histones (100 μg/mL) induced IEC-6 apoptosis through activating caspase 3 and necroptosis through up-regulation of receptor-interacting serine/threonine protein kinase 1 and 3 (RIPK1 and RIPK3), phosphorylated mixed-lineage kinase domain-like protein (p-MLKL) along with the decrease of caspase-8. Histones treatment disturbed zonular occludens 1 (ZO-1) expression and increased permeability of IEC-6 cell monolayer. In vivo, histones 50 mg/kg injection caused mice intestinal edema, loss apex of villus, epithelial lifting down the sides of the villi, and increased neutrophil infiltration. Elevation of serum intestinal fatty acid binding protein (I-FABP), D-lactate, or Diamine oxidase (DAO) and loss of tight junction protein, ZO-1, at 3 h and 6 h after histones injection strongly indicated severe intestinal epithelium injury, which led to increased permeability of the intestine. In conclusion, extracellular histones cause intestinal epithelial damage via direct cytotoxicity. Consequently, intestinal epithelial tight junction and barrier integrity are disrupted, which may play pivotal roles in diverse diseases.

Accurate prediction of acute pancreatitis severity based on genome-wide cell free DNA methylation profiles

Background

Patients with severe acute pancreatitis (SAP) have a high mortality, thus early diagnosis and interventions are critical for improving survival. However, conventional tests are limited in acute pancreatitis (AP) stratification. We aimed to assess AP severity by integrating the informative clinical measurements with cell free DNA (cfDNA) methylation markers.

Methods

One hundred and seventy-five blood samples were collected from 61 AP patients at multiple time points, plus 24 samples from healthy individuals. Genome-wide cfDNA methylation profiles of all samples were characterized with reduced representative bisulfite sequencing. Clinical blood tests covering 93 biomarkers were performed on AP patients within 24 h. SAP predication models were built based on cfDNA methylation and conventional blood biomarkers separately and in combination.

Results

We identified 565 and 59 cfDNA methylation markers informative for acute pancreatitis and its severity. These markers were used to develop prediction models for AP and SAP with area under the receiver operating characteristic of 0.92 and 0.81, respectively. Twelve blood biomarkers were systematically screened for a predictor of SAP with a sensitivity of 87.5% for SAP, and a specificity of 100% in mild acute pancreatitis, significantly higher than existing blood tests. An expanded model integrating 12 conventional blood biomarkers with 59 cfDNA methylation markers further improved the SAP prediction sensitivity to 92.2%.

Conclusions

These findings have demonstrated that accurate prediction of SAP by the integration of conventional and novel blood molecular markers, paving the way for early and effective SAP intervention through a non-invasive rapid diagnostic test.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01217-z.

Extracellular Histones H3 as a Prognostic Blood Marker for Delayed Liver Function Recovery After Donor Hepatectomy

BACKGROUND

Early prediction of liver dysfunction after liver resection remains a challenge. We hypothesized that extracellular histone concentrations are a promising new biomarker for the detection of liver injury after donor hepatectomy.

METHODS

This prospective study considered 93 living donors who underwent hepatectomy. Blood samples of donors were collected on postoperative day 1, and histone levels in the plasma samples of the patients were measured with total histone H3 sandwich ELISA kits. Among 86 right lobe donors, 23 (26.7%) were deemed to have a delayed liver function recovery according to the International Study Group of Liver Surgery's definition of posthepatectomy liver failure, whereas 63 (73.3%) were considered to have an adequate liver function recovery.

RESULTS

The area under the receiver operating characteristic (ROC) curve for circulating histones in predicting persistent liver dysfunction was 0.618 ± 0.06 (95% confidence interval [CI], 0.501-0.735; P = .091). The cutoff point value obtained from the analysis of ROC curves was 0.895, with a sensitivity of 95.7% and a specificity of 32.9%, respectively, for examining a delayed liver function recovery (P = .015). The Fisher analysis significantly verified these results empirical influence function % 7.90 (95% CI, 3.91-11.90; P = .006). The univariate analysis determined that postoperative histones were identified as an independent risk factor of delayed liver function recovery (odds ratio, 10.8; 95% CI, 1.4-84.9; P = .024).

CONCLUSIONS

The circulating histone negatively correlates with liver dysfunctions after donor hepatectomy and had the best value in predicting liver dysfunction within 24 hours after liver resection.

Evaluation of serum histone concentrations and their associations with hemostasis, markers of inflammation, and outcome in dogs with naturally occurring acute pancreatitis

OBJECTIVE

To compare serum concentrations of histones and inflammatory markers in dogs with acute pancreatitis and healthy control dogs, investigate associations of these variables with coagulation test results and survival (vs nonsurvival) to hospital discharge, and examine the prognostic utility of clinical findings and routine laboratory and coagulation tests in affected dogs.

ANIMALS

36 dogs.

PROCEDURES

Dogs with findings consistent with acute pancreatitis (n = 29) and healthy control dogs (7) were enrolled in a prospective, observational study. Serum concentrations of histones, interleukin (IL)-6, and tumor-necrosis factor-α were assessed for all dogs. Clinical (including ultrasonographic) findings, relevant history, routine laboratory and coagulation test results, and outcomes were recorded for dogs with pancreatitis. Variables were assessed to determine an association with outcome for affected dogs and hospitalization time for survivors; histone concentrations and markers of inflammation were compared among survivors, nonsurvivors, and controls. Correlation between quantitative variables was investigated.

RESULTS

Serum histone and IL-6 concentrations did not differentiate survivors (n = 23) from nonsurvivors (6); IL-6 concentrations in affected dogs were correlated with 1,2-o-dilauryl-rac-glycero glutaric acid-(6'-methylresorufin) ester lipase activity (r_S = 0.436) and hospitalization time (r_S = 0.528). Pancreatitis-associated peritoneal fluid, obtundation, and jaundice were more common, and serum bilirubin concentration, serum alanine aminotransferase and aspartate aminotransferase activities, and prothrombin and activated partial thromboplastin times were greater in nonsurvivors than in survivors. Thromboelastometric changes consistent with hypercoagulability were detected in survivors; hypocoagulability was detected in 2 nonsurvivors.

CONCLUSIONS AND CLINICAL RELEVANCE

Serum histone concentrations were not associated with presence of acute pancreatitis or outcome for affected dogs. Further research is needed to investigate the clinical and therapeutic implications of hypocoagulability, hepatocellular injury, and pancreatitis-associated peritoneal fluid in affected dogs.

Chaiqin chengqi decoction ameliorates acute pancreatitis in mice via inhibition of neuron activation-mediated acinar cell SP/NK1R signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Chaiqin chengqi decoction (CQCQD) and its derivatives have been widely used in China for the early management of patients with acute pancreatitis (AP). Numerous studies demonstrate the anti-inflammatory and anti-oxidative effects of CQCQD and derivatives, but whether these effects can be attributed to suppressing neurogenic inflammation, has never been studied.

AIM OF THE STUDY

To investigate the effects of CQCQD on substance P (SP)-neurokinin 1 receptor (NK1R) based neurogenic inflammation in an experimental AP model.

MATERIAL AND METHODS

For AP patients on admission, pain score was accessed by visual analog scale (VAS); the levels of serum SP and expressions of pancreatic SP and NK1R were also determined. For in vivo study, mice received 7 intraperitoneal injections of cerulein (50 μg/kg) at hourly intervals to induce AP, whilst controls received normal saline injections. In the treatment groups, CQCQD (10 g/kg, 200 μl) was intragastrically given at the third, fifth, and seventh of the cerulein injection or the NK1R antagonist CP96345 (5 mg/kg) was intraperitoneally injected 30 min before the first cerulein administration. The von Frey test was performed to evaluate pain behavior. Animals were sacrificed at 12 h from the first cerulein/saline injection for severity assessment. Pharmacology network analysis was used to identify active ingredients of CQCQD for AP and pain. In vitro, freshly isolated pancreatic acinar cells were pre-treated with CQCQD (5 mg/ml), CP96345 (1 μM), or selected active compounds of CQCQD (12.5, 25, and 50 μM) for 30 min, followed by SP incubation for another 30 min.

RESULTS

The VAS score as well as the levels of serum SP and expressions of pancreatic SP-NK1R were up-regulated in moderately severe and severe patients compared with those with mild disease. CQCQD, but not CP96345, consistently and significantly ameliorated pain, pancreatic necrosis, and systemic inflammation in cerulein-induced AP as well as inhibited NK1R internalization of pancreatic acinar cells. These effects of CQCQD were associated with reduction of pancreatic SP-NK1R and neuron activity in pancreas, dorsal root ganglia, and spinal cord. Baicalin, emodin, and magnolol, the top 3 active components of CQCQD identified via pharmacology network analysis, suppressed NK1R internalization and NF-κB signal pathway activation in isolated pancreatic acinar cells.

CONCLUSIONS

CQCQD ameliorated cerulein-induced AP and its associated pain via inhibiting neuron activation-mediated pancreatic acinar cell SP-NK1R signaling pathways and its active compounds baicalin, emodin, and magnolol contributed to this effect.

Acinar cell NLRP3 inflammasome and gasdermin D (GSDMD) activation mediates pyroptosis and systemic inflammation in acute pancreatitis

BACKGROUND AND PURPOSE

Pyroptosis is a lytic form of pro-inflammatory cell death characterised as caspase 1 dependent with canonical NLRP3 inflammasome-induced gasdermin D (GSDMD) activation. We aimed to investigate the role of acinar pyroptotic cell death in pancreatic injury and systemic inflammation in AP.

EXPERIMENTAL APPROACH

Pancreatic acinar pyroptotic cell death pathway activation upon pancreatic toxin stimulation in vitro and in vivo was investigated. Effects of pharmacological (NLRP3 and caspase-1 inhibitors), constitutive (Nlrp3^-/- , Casp1^-/- and Gsdmd^-/- ) and acinar cell conditional (Pdx1^Cre Nlrp3^Δ/Δ and Pdx1^Cre Gsdmd^Δ/Δ ) genetic inhibition on pyroptotic acinar cell death, pancreatic necrosis and systemic inflammation were assessed using mouse AP models (caerulein, sodium taurocholate and l-arginine). Effects of Pdx1^Cre Gsdmd^Δ/Δ versus myeloid conditional knockout (Lyz2^Cre Gsdmd^Δ/Δ ) and Gsdmd^-/- versus receptor-interacting protein 3 (RIP3) inhibitor were compared in CER-AP.

KEY RESULTS

There was consistent pyroptotic acinar cell death upon pancreatic toxin stimulation both in vitro and in vivo, which was significantly reduced by pharmacological or genetic pyroptosis inhibition. Pdx1^Cre Gsdmd^Δ/Δ but not Lyz2^Cre Gsdmd^Δ/Δ mice showed significantly reduced pyroptotic acinar cell death, pancreatic necrosis and systemic inflammation in caerulein-AP. Co-application of RIP3 inhibitor on Gsdmd^-/- mice further increased protection on caerulein-AP.

CONCLUSION AND IMPLICATIONS

This work demonstrates a critical role for NLRP3 inflammasome and GSDMD activation-mediated pyroptosis in acinar cells, linking pancreatic necrosis and systemic inflammation in AP. Targeting pyroptosis signalling pathways holds promise for specific AP therapy.

Circulating Histones in Sepsis: Potential Outcome Predictors and Therapeutic Targets

Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection and is associated with high morbidity and mortality. Circulating histones (CHs), a group of damage-associated molecular pattern molecules mainly derived from neutrophil extracellular traps, play a crucial role in sepsis by mediating inflammation response, organ injury and death through Toll-like receptors or inflammasome pathways. Herein, we first elucidate the molecular mechanisms of histone-induced inflammation amplification, endothelium injury and cascade coagulation activation, and discuss the close correlation between elevated level of CHs and disease severity as well as mortality in patients with sepsis. Furthermore, current state-of-the-art on anti-histone therapy with antibodies, histone-binding proteins (namely recombinant thrombomodulin and activated protein C), and heparin is summarized to propose promising approaches for sepsis treatment.

Macrophage migration inhibitory factor is an early marker of severe acute pancreatitis based on the revised Atlanta classification

BACKGROUND

Various serum markers for early identification of severe acute pancreatitis (SAP) have been studied. Serum macrophage migration inhibitory factor (MIF) was reported to be correlated with severity of acute pancreatitis (AP) based on the 1992 Atlanta classification. However, MIF has never been proven to be predictive of disease severity based on the revised Atlanta classification (RAC). The potential predictive value of MIF needs to be further validated.

METHODS

Consecutive patients with AP within 48 h after symptom onset and 10 healthy control volunteers were enrolled prospectively. Serum MIF levels were measured by enzyme-linked immunosorbent assay (ELISA). The predictive value of MIF, clinical scores and other serum markers were determined.

RESULTS

Among 143 patients with AP, there were 52 (36.4%), 65 (45.5%) and 26 (18.1%) with mild, moderate and severe disease based on the RAC respectively. Compared with healthy volunteers, serum levels of MIF were significantly higher in AP patients, especially those with SAP (P < 0.001). Multivariate regression analysis indicated that increased serum MIF (cut-off 2.30 ng/ml, OR = 3.16, P = 0.008), IL-6 (cut-off 46.8 pg/ml, OR = 1.21, P = 0.043), APACHE II score (cut-off 7.5, OR = 2.57, P = 0.011) and BISAP score (cut-off 1.5, OR = 1.01, P = 0.038) were independent risk factors for predicting SAP (P < 0.05). By using the area under the receiver operating characteristic (ROC) curve (AUC), MIF (AUC 0.950) demonstrated more excellent discriminative power for predicting SAP than APACHE II (AUC 0.899), BISAP (AUC 0.886), and IL-6 (AUC 0.826).

CONCLUSIONS

Serum MIF is a valuable early marker for predicting the severity of AP based on the RAC.

Extracellular histones stimulate collagen expression in vitro and promote liver fibrogenesis in a mouse model via the TLR4-MyD88 signaling pathway

BACKGROUND

Liver fibrosis progressing to liver cirrhosis and hepatic carcinoma is very common and causes more than one million deaths annually. Fibrosis develops from recurrent liver injury but the molecular mechanisms are not fully understood. Recently, the TLR4-MyD88 signaling pathway has been reported to contribute to fibrosis. Extracellular histones are ligands of TLR4 but their roles in liver fibrosis have not been investigated.

AIM

To investigate the roles and potential mechanisms of extracellular histones in liver fibrosis.

METHODS

In vitro, LX2 human hepatic stellate cells (HSCs) were treated with histones in the presence or absence of non-anticoagulant heparin (NAHP) for neutralizing histones or TLR4-blocking antibody. The resultant cellular expression of collagen I was detected using western blotting and immunofluorescent staining. In vivo, the CCl4-induced liver fibrosis model was generated in male 6-week-old ICR mice and in TLR4 or MyD88 knockout and parental mice. Circulating histones were detected and the effect of NAHP was evaluated.

RESULTS

Extracellular histones strongly stimulated LX2 cells to produce collagen I. Histone-enhanced collagen expression was significantly reduced by NAHP and TLR4-blocking antibody. In CCl4-treated wild type mice, circulating histones were dramatically increased and maintained high levels during the duration of fibrosis-induction. Injection of NAHP not only reduced alanine aminotransferase and liver injury scores, but also significantly reduced fibrogenesis. Since the TLR4-blocking antibody reduced histone-enhanced collagen I production in HSC, the CCl4 model with TLR4 and MyD88 knockout mice was used to demonstrate the roles of the TLR4-MyD88 signaling pathway in CCl4-induced liver fibrosis. The levels of liver fibrosis were indeed significantly reduced in knockout mice compared to wild type parental mice.

CONCLUSION

Extracellular histones potentially enhance fibrogenesis via the TLR4-MyD88 signaling pathway and NAHP has therapeutic potential by detoxifying extracellular histones.

Neutralizing the pathological effects of extracellular histones with small polyanions

Extracellular histones in neutrophil extracellular traps (NETs) or in chromatin from injured tissues are highly pathological, particularly when liberated by DNases. We report the development of small polyanions (SPAs) (~0.9–1.4 kDa) that interact electrostatically with histones, neutralizing their pathological effects. In vitro, SPAs inhibited the cytotoxic, platelet-activating and erythrocyte-damaging effects of histones, mechanistic studies revealing that SPAs block disruption of lipid-bilayers by histones. In vivo, SPAs significantly inhibited sepsis, deep-vein thrombosis, and cardiac and tissue-flap models of ischemia-reperfusion injury (IRI), but appeared to differ in their capacity to neutralize NET-bound versus free histones. Analysis of sera from sepsis and cardiac IRI patients supported these differential findings. Further investigations revealed this effect was likely due to the ability of certain SPAs to displace histones from NETs, thus destabilising the structure. Finally, based on our work, a non-toxic SPA that inhibits both NET-bound and free histone mediated pathologies was identified for clinical development.

Histones, proteins that bind DNA, are toxic for pathogens outside cells but can also cause multi-organ damage as seen in sepsis. Here the authors develop small negatively charged molecules that can be used as histone antidotes, and show that they improve the phenotype in mouse models with histone-related pathologies.

Heparin Attenuates Histone-Mediated Cytotoxicity in Septic Acute Kidney Injury

Histones are considered potential risk factors that contribute to the development of septic acute kidney injury (SAKI) by inducing apoptosis and inflammation. This study aimed to explore the protective effects of heparin on septic acute kidney injury through the neutralization of extracellular histones (EH) and to uncover the underlying mechanism. C57BL mice (16 each) were randomly divided into the sham group, the sepsis group (established by cecal ligation and puncture operation, CLP), and the heparin intervention group. Mice in the heparin intervention group received a subcutaneous injection of unfractionated heparin (0.03 IU/g) 4 h after CLP. At 6 h after the operation, nine mice from each group were sacrificed by the removal of the eyeballs to harvest blood samples; the upper half of the right kidney was used as the study sample. Mice renal tubular epithelial cells cultivated in six-well plates were equally divided into five groups. We cultured cells treated with either histone (40 U), histone (40 U) + heparin (25 IU/ml), histone(40U) + lipopolysaccharides (LPS; 10 μg/ml), or histone (40 U) + LPS (10 μg/ml) + heparin (25 IU/ml) for 6 h. For the histone + heparin group and the histone + LPS + heparin group, histone (and LPS) were treated with heparin simultaneously. Mice in the heparin intervention group showed decreased levels of EH4, neutrophil gelatinase-associated lipocalin (NAGL), kidney injury molecule-1 (KIM-1), tumor necrosis factor-α (TNF-α), and interleukin (IL)-6 in the blood serum, longer average 72-h survival rate, significantly decreased kidney tissue edema, and a clearer glomerular structure coupled with decreased protein and mRNA expression levels of kidney apoptosis-related proteins (cleaved Caspase-3/Caspase-3 and Bax/Bcl-2) compared with those in the sepsis group at 6 h after CLP (P < 0.05). Meanwhile, cells in the heparin intervention group exhibited lower expression levels of serum EH4 and inflammatory cytokines, a lower apoptosis rate, and decreased expression of apoptosis-related proteins, both at protein and mRNA levels, than those in the histone-stimulated group at 6 h after stimulation (P < 0.05). Heparin may alleviate apoptosis and inflammation through the neutralization of histones, thus playing a protective role against septic acute kidney injury.

The Organ Trail: A Review of Biomarkers of Organ Failure

Pediatric organ failure and transplant populations face significant risks of morbidity and mortality. The risk of organ failure itself may be disproportionately higher among pediatric oncology patients, as cancer may originate within and/or metastasize to organs and adversely affect their function. Additionally, cancer directed therapies are frequently toxic to organs and may contribute to failure. Recent reports suggest that nearly half of providers find it difficult to provide prognostic information regarding organ failure due to unknown disease trajectories. Unfortunately, there is a lack of uniform methodology in detecting the early symptoms of organ failure, which may delay diagnosis, initiation of treatment and hinder prognostic planning. There remains a wide array of outstanding scientific questions regarding organ failure in pediatrics but emerging data may change the landscape of prognostication. Liquid biopsy, in which disease biomarkers are detected in bodily fluids, offers a noninvasive alternative to tissue biopsy and may improve prompt detection of organ failure and prognostication. Here, we review potential liquid biopsy biomarkers for organ failure, which may be particularly useful among pediatric oncology patients. We synthesized information from publications obtained on PubMed, Google Scholar, clinicaltrials.gov, and Web of Science and categorized our findings based on the type of biomarker used to detect organ failure. We highlight the advantages and disadvantages specific to each type of organ failure biomarker. While much work needs to be done to advance this field and validate its applicability to pediatric cancer patients facing critical care complications, herein, we highlight promising areas for future discovery.

Assessment of the course of acute pancreatitis in the light of aetiology: a systematic review and meta-analysis

The main causes of acute pancreatitis (AP) are biliary disease, alcohol consumption, hypertriglyceridaemia (HTG) and endoscopic retrograde cholangiopancreatography (ERCP). The aim of this meta-analysis was to evaluate the effects of these aetiological factors on the severity and outcome of AP. Pubmed and Embase were searched between 01/01/2012 and 31/05/2020. Included articles involved adult alcoholic, biliary, HTG- or post-ERCP AP (PAP) patients. Primary outcome was severity, secondary outcomes were organ failures, intensive care unit admission, recurrence rate, pancreatic necrosis, mortality, length of hospital stay, pseudocyst, fluid collection and systematic inflammatory response syndrome. Data were analysed from 127 eligible studies. The risk for non-mild (moderately severe and severe) condition was the highest in HTG-induced AP (HTG-AP) followed by alcoholic AP (AAP), biliary AP (BAP) and PAP. Recurrence rate was significantly lower among BAP vs. HTG-AP or AAP patients (OR = 2.69 and 2.98, 95% CI 1.55-4.65 and 2.22-4.01, respectively). Mortality rate was significantly greater in HTG-AP vs. AAP or BAP (OR = 1.72 and 1.50, 95% CI 1.04-2.84 and 0.96-2.35, respectively), pancreatic necrosis occurred more frequently in AAP than BAP patients (OR = 1.58, 95% CI 1.08-2.30). Overall, there is a potential association between aetiology and the development and course of AP. HTG-AP is associated with the highest number of complications. Furthermore, AAP is likely to be more severe than BAP or PAP. Greater emphasis should be placed on determining aetiology on admission.

Early Rapid Fluid Therapy Is Associated with Increased Rate of Noninvasive Positive-Pressure Ventilation in Hemoconcentrated Patients with Severe Acute Pancreatitis

BACKGROUND/AIMS

Hematocrit is a widely used biomarker to guide early fluid therapy for patients with acute pancreatitis (AP), but there is controversy over whether early rapid fluid therapy (ERFT) should be used in hemoconcentrated patients. This study investigated the association of hematocrit and ERFT with clinical outcomes of patients with AP.

METHODS

Data from prospectively maintained AP database and retrospectively collected fluid management details were stratified according to actual severity defined by revised Atlanta classification. Hemoconcentration and "early" were defined as hematocrit > 44% and the first 6 h of general ward admission, respectively, and "rapid" fluid rate was defined as ≥ 3 ml/kg/h. Patients were allocated into 4 groups for comparisons: group A, hematocrit ≤ 44% and fluid rate < 3 ml/kg/h; group B, hematocrit ≤ 44% and fluid rate ≥ 3 ml/kg/h; group C, hematocrit > 44% and fluid rate < 3 ml/kg/h; and group D, hematocrit > 44% and fluid rate ≥ 3 ml/kg/h. Primary outcome was rate of noninvasive positive-pressure ventilation (NPPV).

RESULTS

A total of 912 consecutive AP patients were analyzed. ERFT has no impact on clinical outcomes of hemoconcentrated, non-severe or all non-hemoconcentrated AP patients. In hemoconcentrated patients with severe AP (SAP), ERFT was accompanied with increased risk of NPPV (odds ratio 5.96, 95% CI 1.57-22.6). Multivariate regression analyses confirmed ERFT and hemoconcentration were significantly and independently associated with persistent organ failure and mortality in patients with SAP.

CONCLUSIONS

ERFT is associated with increased rate of NPPV in hemoconcentrated patients with SAP.

Chaiqin chengqi decoction alleviates severity of acute pancreatitis via inhibition of TLR4 and NLRP3 inflammasome: Identification of bioactive ingredients via pharmacological sub-network analysis and experimental validation

BACKGROUND

Chaiqin chengqi decoction (CQCQD) is a Chinese herbal formula derived from dachengqi decoction. CQCQD has been used for the management of acute pancreatitis (AP) in the West China Hospital for more than 30 years. Although CQCQD has a well-established clinical efficacy, little is known about its bioactive ingredients, how they interact with different therapeutic targets and the pathways to produce anti-inflammatory effects.

PURPOSE

Toll-like receptor 4 (TLR4) and the nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome-mediated pro-inflammatory signaling pathways, play a central role in AP in determining the extent of pancreatic injury and systemic inflammation. In this study, we screened the bioactive ingredients using a pharmacological sub-network analysis based on the TLR4/NLRP3 signaling pathways followed by experimental validation.

METHODS

The main CQCQD bioactive compounds were identified by UPLC-QTOF/MS. The TLR4/NLRP3 targets in AP for CQCQD active ingredients were confirmed through a pharmacological sub-network analysis. Mice received 7 intraperitoneal injections of cerulein (50 μg/kg; hourly) to induce AP (CER-AP), while oral gavage of CQCQD (5, 10, 15 and 20 g/kg; 3 doses, 2 hourly) was commenced at the 3rd injection of cerulein. Histopathology and biochemical indices were used for assessing AP severity, while polymerase chain reaction, Western blot and immunohistochemistry analyses were used to study the mechanisms. Identified active CQCQD compounds were further validated in freshly isolated mouse pancreatic acinar cells and cultured RAW264.7 macrophages.

RESULTS

The main compounds from CQCQD belonged to flavonoids, iridoids, phenols, lignans, anthraquinones and corresponding glycosides. The sub-network analysis revealed that emodin, rhein, baicalin and chrysin were the compounds most relevant for directly regulating the TLR4/NLRP3-related proteins TLR4, RelA, NF-κB and TNF-α. In vivo, CQCQD attenuated the pancreatic injury and systemic inflammation of CER-AP and was associated with reduced expression of TLR4/NLRP3-related mRNAs and proteins. Emodin, rhein, baicalin and chrysin significantly diminished pancreatic acinar cell necrosis with varied effects on suppressing the expression of TLR4/NLRP3-related mRNAs. Emodin, rhein and chrysin also decreased nitric oxide production in macrophages and their combination had synergistic effects on alleviating cell death as well as expression of TLR4/NLRP3-related proteins.

CONCLUSIONS

CQCQD attenuated the severity of AP at least in part by inhibiting the TLR4/NLRP3 pro-inflammatory pathways. Its active ingredients, emodin, baicalin, rhein and chrysin contributed to these beneficial effects.

Kidney injury induced by elevated histones in community-acquired pneumonia

Previous studies showed that extracellular histones could damage organs, but the role of extracellular histones in pneumonia patients with acute kidney injury (AKI) is unknown. This study aims to investigate the impact of extracellular histones on patients with community-acquired pneumonia (CAP) developed AKI. Blood samples were obtained within 24 h after admission to hospital from patients who were diagnosed with CAP. According to the discharge diagnosis, the patients were divided into 2 groups (Non-AKI and AKI). In vitro, A549 cells were treated with lipopolysaccharides (LPS) and conditioned media were collected. HK2 cells were exposed to the conditioned media or not. Cells proliferation and apoptosis of HK2 were determined. Clinically, Log₂ Histones (OR 3.068; 95% CI 1.544-6.097, P = 0.001) and estimated glomerular filtration rate (eGFR) (OR 0.945; 95% CI 0.914-0.978, P = 0.001) were predictors of AKI in CAP patients. Compared to the lower histones group, patients in the higher histones group were more likely to be admitted to ICU, receive mechanical ventilation, and have a longer length of in-hospital stay. In vitro, A549 cells injured by LPS released extracellular histones, in conditioned media which significantly promoted HK2 cells apoptosis. Extracellular histones was a high risk factor for developing AKI in CAP patients and a predictor of worse short-term outcomes. We also showed that extracellular histones in conditioned media damaged HK2 cells.Trial registration number: KY20181102-03; Date of registration: 20181102.

Extracellular Histone H3 Induces Pyroptosis During Sepsis and May Act Through NOD2 and VSIG4/NLRP3 Pathways

Background: Histones could be released from the nucleus when stimulated. Increasing evidence has shown that extracellular histones are associated with a variety of inflammation and diseases. Nucleotide binding oligomerzation domain 2 (NOD2) belongs to the NOD like receptor (NLR) family and is reported to promote apoptosis and aggravate inflammatory response. And V-set and immunoglobulin domain containing 4 (VSIG4), a B7 family-related protein, has been confirmed to mediate transcriptional inhibition of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3). However, little is known about the impact of extracellular histones on NOD2 or VSIG4 signal transduction. In this study, we aim to explore the effect and mechanism of extracellular histone H3 on pyroptosis. Aim: The purpose of this work was to investigate the mechanism of extracellular histone H3 on pyroptosis in sepsis. Methods: Lipopolysaccharide (LPS) and histone H3 were used to induce sepsis mice model and damage in ANA-1 macrophages. H3 antibody was applied to antagonize the effect of histone H3. NOD2 inhibitor NOD-IN-1 and VSIG4-siRNA were used to investigate the mechanism of histone H3 on pyroptosis. Enzyme linked immune sorbent assay (ELISA) was applied to detect the level of extracellular histone H3. Real-time PCR and Western blotting were employed to detect the key mRNA and protein levels. The pathology of tissues was detected. Results: The level of extracellular histone H3 was increased after LPS stimulation. The mRNA and protein levels of NLRP3, caspase-1, gasdermin D (GSDMD), interleukin (IL)-1β, IL-18 were increased in LPS group, but suppressed by H3 antibody. And the expression of NOD2, receptor-interacting protein 2 (RIP2) was elevated compared with control group. The expression of VSIG4 was inhibited by LPS and suppression of H3 promoted the protein level of VSIG4. H3 antibody alleviated pathological damages in tissues. Furthermore, the mRNA and protein levels of NOD2 in H3 group was higher compared with control group. The mRNA and protein levels of VSIG4 in H3 group was decreased compared with control group, but up-regulated by NOD-IN-1. Besides, the mRNA and protein levels of VSIG4 in NOD-IN-1 + VSIG4-siRNA group was elevated compared with VSIG4-siRNA group. Conclusions: Extracellular histone H3 induced by LPS could cause pyroptosis during sepsis via NOD2 and VSIG4/NLRP3 pathway.

Aqueous extraction from dachengqi formula granules reduces the severity of mouse acute pancreatitis via inhibition of pancreatic pro-inflammatory signalling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Dachengqi decoction (DCQD) belongs to a family of purgative herbal formulas widely used in China for the treatment of acute pancreatitis (AP). AP is a prevalent digestive disease currently without an effective pharmacological intervention. Formula granules have become the preferred method for delivery of herbal formulation in China given its benefit of potency retention, dosing precision and ease of use. The efficacy of DCQD formula granules (DFGs) in experimental AP models has not been investigated.

AIM OF THE STUDY

To analyse and compare the differences in chemical composition of DFGs, with their aqueous extraction (AE) and chloroform extraction (CE) derivatives. To assess their efficacy on severity and targeted pancreatic pro-inflammatory signalling pathways in freshly isolated acinar cells and two models of experimental AP.

MATERIAL AND METHODS

UPLC-Q-TOF-MS was used to analyse chemical components of DFGs and their extractions. Freshly isolated mouse pancreatic acinar cells were treated with taurolithocholic acid 3-sulphate disodium salt (TLCS, 500 μM) with or without DFGs, AE and CE. Apoptotic and necrotic cell death pathway activation was measured by caspase 3/7 (10 μl/mL) and propidium iodide (PI, 1 μM), respectively, using a fluorescent plate reader. Necrotic acinar cells were also counted by epifluorescence microscopy. Mice received either 7 intraperitoneal injections of caerulein (50 μg/kg) at hourly intervals or retrograde infusion of TLCS (3 mM, 50 μl) to induce AP (CER-AP and TLCS-AP, respectively). In CER-AP, mice received oral gavage of DFGs (2.1, 4.2 and 5.2 g/kg), AE (0.6, 1.2, and 2.4 g/kg) and CE (4, 9 and 17 mg/kg), or matched DFGs (1.8 g/kg) and AE (1 g/kg) for 3 times at 2-hourly intervals, or a single intraperitoneal injection of DCQD-related monomers rhein (20 mg/kg), narigeinine (25 mg/kg), and honokiol (5 mg/kg) begun at the 3rd injection of caerulein. In TLCS-AP, DFGs (4.2 g/kg) were given orally at 1, 3 and 5 h post-surgery. Disease severity and pancreatic pro-inflammatory markers were determined.

RESULTS

The main effective anthraquinones and their glycosides, flavonoids and their glycosides, polyphenols and lignans were found in the DFGs. A higher proportion of polar components including glycosides attached to anthraquinones, phenols and flavonoids was found in AE. Conversely, lower polar components containing methoxy substituted flavonoids and anthraquinones were more abundant in CE. DFGs were given at 4.2 g/kg, a consistent reduction in the pancreatic histopathology score and severity indices was observed in both CER-AP and TLCS-AP. In vitro, AE significantly reduced both apoptotic and necrotic cell death pathway activation, while CE increased TLCS-induced acinar cell necrosis. In vivo, AE at dose of 1.2 g/kg consistently reduced pancreatic histopathological scores and myeloperoxidase in the CER-AP that were associated with suppressed expression of pro-inflammatory meditator mRNAs and proteins. CE increased lung myeloperoxidase and failed to protect against CER-AP in all dosages. AE was demonstrated to be more effective than DFGs in reducing pancreatic histopathological scores and myeloperoxidase.

CONCLUSIONS

AE from DFGs alleviated the severity of mouse AP models via an inhibition of pancreatic pro-inflammatory signalling pathways. Efficacy of AE on experimental AP was more potent than its original DFGs and DCQD monomers.

Circulating Histones Are Major Mediators of Multiple Organ Dysfunction Syndrome in Acute Critical Illnesses

OBJECTIVES

Multiple organ dysfunction syndrome is characterized by simultaneous multiple organ failure, which is the leading cause of death in acute critically ill patients. However, what mediates multiple organ dysfunction syndrome is not fully understood. The discovery of toxic effects by extracellular histones on different individual organs strongly suggests their involvement in multiple organ dysfunction syndrome. In this study, we investigate whether circulating histones are major mediators of multiple organ dysfunction syndrome in acute critical illnesses.

DESIGN

Combination of retrospective clinical studies and animal models with intervention.

SETTING

ICU in a tertiary hospital and research laboratories.

PATIENTS

Four hundred and twenty ICU patients, including sepsis (140), severe trauma (63), severe pancreatitis (89), and other admission diagnoses (128).

LABORATORY INVESTIGATION

Cells from major organs are treated with calf thymus histones or histone-containing sera. Animal models for sepsis, trauma, and acute pancreatitis are treated with antihistone reagents.

INTERVENTION

Antihistone reagents in in vitro, ex vivo, and animal models.

MEASUREMENT AND MAIN RESULTS

Retrospective analysis of a prospectively recruited ICU cohort demonstrated a strong correlation between circulating histones and organ injury markers and Sequential Organ Failure Assessment scores. Ex vivo experiments showed that patient sera containing high histone levels were toxic to cultured cells from different origins, suggesting their universal toxicity to multiple organs. Animal models of sepsis, trauma, and pancreatitis further demonstrated a temporal correlation between histone levels and disease severity and multiple organ injury. Importantly, antihistone reagents, that is, antihistone single-chain variable fragment and nonanticoagulant heparin, could dramatically reduce multiple organ injury, particularly of the heart and lungs, and improve survival in mouse models.

CONCLUSIONS

High levels of circulating histones are major mediators of multiple organ dysfunction syndrome. Our results indicate that monitoring upon ICU admission could inform on disease severity and developing antihistone therapy holds great potential of reducing multiple organ dysfunction syndrome and improving survival of critically ill patients.

Multifactorial Scores and Biomarkers of Prognosis of Acute Pancreatitis: Applications to Research and Practice

Acute pancreatitis (AP) is a severe inflammation of the pancreas presented with sudden onset and severe abdominal pain with a high morbidity and mortality rate, if accompanied by severe local and systemic complications. Numerous studies have been published about the pathogenesis of AP; however, the precise mechanism behind this pathology remains unclear. Extensive research conducted over the last decades has demonstrated that the first 24 h after symptom onset are critical for the identification of patients who are at risk of developing complications or death. The identification of these subgroups of patients is crucial in order to start an aggressive approach to prevent mortality. In this sense and to avoid unnecessary overtreatment, thereby reducing the financial implications, the proper identification of mild disease is also important and necessary. A large number of multifactorial scoring systems and biochemical markers are described to predict the severity. Despite recent progress in understanding the pathophysiology of AP, more research is needed to enable a faster and more accurate prediction of severe AP. This review provides an overview of the available multifactorial scoring systems and biochemical markers for predicting severe AP with a special focus on their advantages and limitations.

Procalcitonin, C-Reactive Protein, and Neutrophil Ratio Contribute to the Diagnosis and Prognosis of Severe Acute Pancreatitis

BACKGROUND

We aimed to explore the significance of procalcitonin (PCT), C-reactive protein (CRP) and neutrophil ratio (N%) in the early diagnosis, treatment, and prognosis of severe acute pancreatitis (SAP).

METHODS

A total of 104 patients with SAP (SAP group) and 101 patients with mild acute pancreatitis (MAP) (MAP group) admitted to Affiliated Hospital of Jining Medical University, Jining, China were enrolled. The PCT and CRP in serum were detected by a full-automatic biochemical analyzer, and N% in peripheral blood was measured by a hemocyte analyzer.

RESULTS

The peripheral blood PCT, CRP, and N% in the SAP group were significantly higher than those in the MAP group (P<0.001). Multivariate Logistic regression analysis showed that acute physiology and chronic health evaluation II (APACHE II) score, Ranson score, PCT, CRP, and N% were independent risk factors for SAP. The receiver operating characteristic (ROC) curve showed that the area under curve (AUC) of PCT, CRP, and N% in diagnosing SAP were 0.906, 0.840, and 0.834 respectively, while that of combined detection was 0.972. The AUC of PCT, CRP, and N% in diagnosing SAP death were 0.907, 0.900, and 0.894, respectively.

CONCLUSIONS

Peripheral blood PCT, CRP, and N% contribute to the diagnosis and prognosis of SAP.

Combinatory antibiotic treatment protects against experimental acute pancreatitis by suppressing gut bacterial translocation to pancreas and inhibiting NLRP3 inflammasome pathway

Gut bacterial translocation following impaired gut barrier is a critical determinant of initiating and aggravating acute pancreatitis (AP). Antibiotic combination (ABX; vancomycin, neomycin and polymyxin b) is capable of reducing gut bacteria, but its efficacy in AP prevention and the underlying mechanism have not been investigated yet. AP was induced in BALB/c mice by caerulein (CAE) hyperstimulation. We found that ABX supplementation attenuated the severity of AP as evidenced by reduced pancreatic oedema and myeloperoxidase activity. The protective effect was also confirmed by improved histological morphology of the pancreas and decreased pro-inflammatory markers (IL-1β, TNF-α, MCP-1) in pancreas. ABX administration inhibits the activation of colonic TLR4/NLRP3 inflammasome pathway. Subsequently, down-regulated NLRP3 resulted in decreased colonic pro-inflammation (IL-1β, IL-6, MCP-1) and enhanced gut physical barrier as evidenced by up-regulation of tight junction proteins including occludin, claudin-1 and ZO-1, as well as improved histological morphology of the colon. Together, combinatory ABX therapy inhibited the translocation of gut bacteria to pancreas and its amplification effects on pancreatic inflammation by inhibiting the pancreatic NLRP3 pathway, and inhibiting intestinal-pancreatic inflammatory responses. The current study provides the basis for potential clinical application of ABX in AP.

Hypertriglyceridaemia-associated acute pancreatitis: diagnosis and impact on severity

BACKGROUND

The level of hypertriglyceridaemia (HTG) at which the risk of acute pancreatitis (AP) increases and the impact of HTG on AP attributable to other aetiologies remains unclear.

METHODS

We compared clinical outcomes of patients admitted within 48 h of the onset of abdominal pain from a first episode of AP and admission serum triglyceride levels of either <5.65 mmol/l (<500 mg/dl) or ≥5.65 to <11.3 mmol/l (moderate HTG) or ≥11.3 mmol/l (≥1000 mg/dl, severe HTG).

RESULTS

Among a cohort of 1,233 patients with AP there were significant progressive increases in all major deleterious clinical outcomes including mortality (all P_trend < 0.05) that were directly dependent on admission triglyceride levels. Outcomes were improved by earlier presentation (<24 h compared to 24-48 h from abdominal pain onset). Patients with severe HTG and a concomitant aetiology (n = 68) had significantly more persistent organ failure, pancreatic necrosis and longer hospital stays (P < 0.05) than those with severe HTG alone (n = 206).

CONCLUSIONS

There appears to be an association between HTG grade and the severity of AP. Severe HTG significantly increased the severity of AP, over AP attributable to other aetiologies. Moderate as well as severe HTG can be used as a criterion for the diagnosis of HTG-associated AP.

Precision medicine for acute pancreatitis: current status and future opportunities

Acute pancreatitis is a common inflammatory condition affecting the pancreas, predominantly caused by gallstones, alcohol excess, and hypertriglyceridaemia, with severe disease carrying up to 50% mortality. Despite significant research and preclinical promise, no targeted drug treatments exist for the disease and precision medicine approaches are lacking significantly, when compared to other health conditions. Advances in omics applications will facilitate improved preclinical models and target identification as well as biomarker discovery for refined trial design, focusing on risk stratification, subject selection, and outcome determination. Randomised treatment of Acute Pancreatitis with Infliximab: Double-blind, placebo-controlled, multi-centre trial (RAPID-I) is a pioneering trial, currently under way in acute pancreatitis, which may serve as an innovative model for the implementation of precision medicine strategies for acute pancreatitis in the future.

The heparin-binding proteome in normal pancreas and murine experimental acute pancreatitis

Acute pancreatitis (AP) is acute inflammation of the pancreas, mainly caused by gallstones and alcohol, driven by changes in communication between cells. Heparin-binding proteins (HBPs) play a central role in health and diseases. Therefore, we used heparin affinity proteomics to identify extracellular HBPs in pancreas and plasma of normal mice and in a caerulein mouse model of AP. Many new extracellular HBPs (360) were discovered in the pancreas, taking the total number of HBPs known to 786. Extracellular pancreas HBPs form highly interconnected protein-protein interaction networks in both normal pancreas (NP) and AP. Thus, HBPs represent an important set of extracellular proteins with significant regulatory potential in the pancreas. HBPs in NP are associated with biological functions such as molecular transport and cellular movement that underlie pancreatic homeostasis. However, in AP HBPs are associated with additional inflammatory processes such as acute phase response signalling, complement activation and mitochondrial dysfunction, which has a central role in the development of AP. Plasma HBPs in AP included known AP biomarkers such as serum amyloid A, as well as emerging targets such as histone H2A. Other HBPs such as alpha 2-HS glycoprotein (AHSG) and histidine-rich glycoprotein (HRG) need further investigation for potential applications in the management of AP. Pancreas HBPs are extracellular and so easily accessible and are potential drug targets in AP, whereas plasma HBPs represent potential biomarkers for AP. Thus, their identification paves the way to determine which HBPs may have potential applications in the management of AP.

Organ Failure Due to Systemic Injury in Acute Pancreatitis

Acute pancreatitis may be associated with both local and systemic complications. Systemic injury manifests in the form of organ failure, which is seen in approximately 20% of all cases of acute pancreatitis and defines "severe acute pancreatitis." Organ failure typically develops early in the course of acute pancreatitis, but also may develop later due to infected pancreatic necrosis-induced sepsis. Organ failure is the most important determinant of outcome in acute pancreatitis. We review here the current understanding of the risk factors, pathophysiology, timing, impact on outcome, and therapy of organ failure in acute pancreatitis. As we discuss the pathophysiology of severe systemic injury, the distinctions between markers and mediators of severity are highlighted based on evidence supporting their causality in organ failure. Emphasis is placed on clinically relevant end points of organ failure and the mechanisms underlying the pathophysiological perturbations, which offer insight into potential therapeutic targets to treat.

Multimodal Transgastric Local Pancreatic Hypothermia Reduces Severity of Acute Pancreatitis in Rats and Increases Survival

BACKGROUND & AIMS

Acute pancreatitis (AP) of different etiologies is associated with the activation of different signaling pathways in pancreatic cells, posing challenges to the development of targeted therapies. We investigated whether local pancreatic hypothermia, without systemic hypothermia, could lessen the severity of AP induced by different methods in rats.

METHODS

A urethane balloon with 2 polyurethane tubes was placed inside the stomach of rats. AP was induced in Wistar rats by the administration of cerulein or glyceryl tri-linoleate (GTL). Then, cold water was infused into the balloon to cool the pancreas. Pancreatic temperatures were selected based on those found to decrease acinar cell injury. An un-perfused balloon was used as a control. Pancreatic and rectal temperatures were monitored, and an infrared lamp or heating pad was used to avoid generalized hypothermia. We collected blood, pancreas, kidney, and lung tissues and analyzed them by histology, immunofluorescence, immunoblot, cytokine and chemokine magnetic bead, and DNA damage assays. The effect of hypothermia on signaling pathways initiated by cerulein and GTL was studied in acinar cells.

RESULTS

Rats with pancreatic cooling developed less severe GTL-induced AP compared with rats that received the control balloon. In acinar cells, cooling decreased the lipolysis induced by GTL, increased the micellar form of its fatty acid, lowered the increase in cytosolic calcium, prevented the loss of mitochondrial membrane potential (by 70%-80%), and resulted in a 40%-50% decrease in the uptake of a fatty acid tracer. In rats with AP, cooling decreased pancreatic necrosis by 48%, decreased serum levels of cytokines and markers of cell damage, and decreased markers of lung and renal damage. Pancreatic cooling increased the proportions of rats surviving 6 hours after induction of AP (to 90%, from <10% of rats that received the control balloon). In rats with cerulein-induced AP, pancreatic cooling decreased pancreatic markers of apoptosis and inflammation.

CONCLUSIONS

In rats with AP, transgastric local pancreatic hypothermia decreases pancreatic necrosis, apoptosis, inflammation, and markers of pancreatitis severity and increases survival.

Extracellular Histones Activate Plasma Membrane Toll-Like Receptor 9 to Trigger Calcium Oscillations in Rat Pancreatic Acinar Tumor Cell AR4-2J

In acute pancreatitis, histones are released by infiltrating neutrophils, but how histones modulate pancreatic acinar cell function has not been investigated. We have examined histone modulation of rat pancreatic acini and pancreatic acinar tumor cell AR4-2J by calcium imaging. Histones were found to have no effect on calcium in pancreatic acini but blocked calcium oscillations induced by cholecystokinin or acetylcholine. Both mixed (Hx) and individual (H1, H2A, H2B, H3, H4) histones induced calcium oscillations in AR4-2J. RT-PCR and Western blot verified the expression of histone-targeted Toll-like receptor (TLR) 2, 4 and 9. Immunocytochemistry identified TLR2/TLR4 on apical plasma membrane and TLR9 in zymogen granule regions in pancreatic acini. TLR2 was found on neighboring and TLR9 on peripheral plasma membranes, but TLR4 was in the nucleus in AR4-2J clusters. Neither TLR2 agonist zymosan-A nor TLR4 agonist lipopolysaccharide had any effect on calcium, but TLR9 agonist ODN1826 induced calcium oscillations; TLR9 antagonist ODN2088 blocked H4-induced calcium oscillations in AR4-2J, which also disappeared after treatment of AR4-2J with glucocorticoid dexamethasone, with concurrent TLR9 migration from plasma membrane to cell interiors. TLR9 down regulation with siRNA suppressed H4-induced calcium oscillations. These data together suggest that extracellular histones activate plasma membrane TLR9 to trigger calcium oscillations in AR4-2J cells.

Biology, role and therapeutic potential of circulating histones in acute inflammatory disorders

Histones are positively charged nuclear proteins that facilitate packaging of DNA into nucleosomes common to all eukaryotic cells. Upon cell injury or cell signalling processes, histones are released passively through cell necrosis or actively from immune cells as part of extracellular traps. Extracellular histones function as microbicidal proteins and are pro‐thrombotic, limiting spread of infection or isolating areas of injury to allow for immune cell infiltration, clearance of infection and initiation of tissue regeneration and repair. Histone toxicity, however, is not specific to microbes and contributes to tissue and end‐organ injury, which in cases of systemic inflammation may lead to organ failure and death. This review details the processes of histones release in acute inflammation, the mechanisms of histone‐related tissue toxicity and current and future strategies for therapy targeting histones in acute inflammatory diseases.