Multiple Organ Failure In Sepsis Research Articles

YL-109 attenuates sepsis-associated multiple organ injury through inhibiting the ERK/AP-1 axis and pyroptosis by upregulating CHIP

Sepsis is a severe inflammatory disorder that can lead to life-threatening multiple organ injury. Lipopolysaccharide (LPS)-induced inflammation is the leading cause of multiple organ failure in sepsis. This study aimed to explore the effect of a novel agent, 2-(4-hydroxy-3-methoxyphenyl)-benzothiazole (YL-109), on LPS-induced multiple organ injury and the molecular mechanisms underlying these processes. The results showed that YL-109 protected against LPS-induced high mortality, cardiac dysfunction, pulmonary and intestinal injury through inhibiting the proinflammatory response, NLRP3 expression and pyroptosis-associated indicators in mouse tissues. YL-109 suppressed LPS-initiated cytokine release, pyroptosis and pyroptosis-related protein expression in HL-1, IEC-6 and MLE-12 cells, which was consistent with the results of the in vivo experiments. Mechanistically, YL-109 reduces phosphorylated ERK (extracellular signal-regulated kinase) levels and NF-κB activation, which are achieved through upregulating CHIP (carboxy terminus of Hsc70-interacting protein) expression, thereby inhibiting c-Jun and c-Fos activation as well as NLRP3 expression. As an E3 ligase, CHIP overexpression obviously promoted the degradation of phosphorylated ERK and inhibited the expression of NF-κB-mediated NLRP3 in cells stimulated with LPS. The protective effects of YL-109 against cardiac, pulmonary and intestinal damage, inflammation and pyroptosis caused by LPS were eliminated in CHIP knockout mice. Our results not only reveal the protective effect and molecular mechanism of YL-109 against LPS-mediated organs damage but also provide additional insights into the effect of CHIP on negatively regulating pyroptosis and inflammatory pathways.

The Dynamics of Platelet Content in Patients with Diffuse Peritonitis as a Predictor of Disease Outcome

BACKGROUND. Absolute numbers of platelets are of key importance for determining the severity of multiple organ failure in sepsis, while their fluctuations within normal values are not taken into account. At the same time, early detection of a downward trend in this parameter may have greater predictive value in predicting disease outcomes. AIM OF STUDY. To identify trends in changes in platelet levels in patients with widespread peritonitis and determine the possible relationship of these changes with the outcome of the disease. MATERIAL AND METHODS. The basis of the work was an analysis of the results of treatment of 220 patients with diffuse secondary peritonitis who were treated at the Elizavetinskaya Hospital in 2013–2019. A correlation analysis was conducted to identify relationships between disease outcomes, assessed according to the severity of postoperative complications, and the degree of platelet reduction, expressed in platelet ratio. The further ROC analysis allowed us to identify a threshold value of the platelet ratio, which excess indicated a high risk of an unfavorable outcome. RESULTS. Based on the data obtained, the threshold value of the platelet ratio in the first two days has no clinical significance. At the same time, starting from the third 3rd day of the postoperative period, the quality of the resulting classifier increased, which confirms the prognostic significance of the threshold value of the platelet ratio, which was 1.72 on the third 3rd day after surgery. In other words, a decrease in platelet levels more than 1.72-fold on the 3rd day indicates a high risk of an unfavorable outcome, which may be associated primarily with intra-abdominal complications. This provision also indirectly confirms the fact that among patients with platelet ratio (PR) values exceeding 1.72 on the 3rd day, 68.7 % ultimately underwent repeated surgical interventions (33 patients out of 48 with high PR values, and the overall mortality rate was 72.1 %.Similar indicators in the subgroup with low PR values were 27.6 % of reoperated patients (29 of 105) and 26.7 % of unfavorable outcomes. CONCLUSION. The results obtained indicate that the degree of platelet reduction, rather than their absolute levels, has greater predictive value in patients operated on for diffuse peritonitis.

Rapidly Inhibiting the Inflammatory Cytokine Storms and Restoring Cellular Homeostasis to Alleviate Sepsis by Blocking Pyroptosis and Mitochondrial Apoptosis Pathways.

Pyroptosis, systemic inflammation, and mitochondrial apoptosis are the three primary contributors to sepsis's multiple organ failure, the ultimate cause of high clinical mortality. Currently, the drugs under development only target a single pathogenesis, which is obviously insufficient. In this study, an acid-responsive hollow mesoporous polydopamine (HMPDA) nanocarrier that is highly capable of carrying both the hydrophilic drug NAD+ and the hydrophobic drug BAPTA-AM, with its outer layer being sealed by the inflammatory targeting peptide PEG-LSA, is developed. Once targeted to the region of inflammation, HMPDA begins depolymerization, releasing the drugs NAD+ and BAPTA-AM. Depletion of polydopamine on excessive reactive oxygen species production, promotion of ATP production and anti-inflammation by NAD+ replenishment, and chelation of BAPTA (generated by BA-AM hydrolysis) on overloaded Ca2+ can comprehensively block the three stages of sepsis, i.e., precisely inhibit the activation of pyroptosis pathway (NF-κB-NLRP3-ASC-Casp-1), inflammation pathway (IL-1β, IL-6, and TNF-α), and mitochondrial apoptosis pathway (Bcl-2/Bax-Cyt-C-Casp-9-Casp-3), thereby restoring intracellular homeostasis, saving the cells in a state of "critical survival," further reducing LPS-induced systemic inflammation, finally restoring the organ functions. In conclusion, the synthesis of this agent provides a simple and effective synergistic drug delivery nanosystem, which demonstrates significant therapeutic potential in a model of LPS-induced sepsis.

Procalcitonin and Adrenomedullin in Infectious Diseases

Calcitonin (CT) and adrenomedullin (ADM) are members of the CT family. Procalcitonin (PCT) is a prohormone of CT. Elevations in serum PCT and ADM levels are associated with severe sepsis and coronavirus disease 2019 (COVID-19). PCT enhances sepsis mortality and it binds to the CGRP receptor, which is a heterodimer of CT receptor-like receptor and receptor activity-modifying protein 1. The N-terminal truncated form of PCT, PCT3-116, is produced by the cleavage of PCT by dipeptidyl peptidase 4 (DPP-4) and is the main form of PCT in serum during sepsis, inducing microvascular permeability. Mid-regional pro-adrenomedullin (MR-proADM) is used instead of ADM as a biological indicator because ADM is rapidly degraded, and MR-proADM is released at the same rate as ADM. ADM reduces endothelial permeability and promotes endothelial stability. Endothelial dysfunction is responsible for multiple organ failure in sepsis and COVID-19 patients. Therefore, ADM may be an important molecule for improving the severity associated with sepsis and COVID-19. This review focuses on the current knowledge of PCT and ADM in sepsis and COVID-19.

Circulating Syndecan-1 as a Predictor of Persistent Thrombocytopenia and Lethal Outcome: A Population Study of Patients With Suspected Sepsis Requiring Intensive Care.

Background: Sepsis is defined as life-threatening organ dysfunction caused by dysregulated host responses to infection. Recent studies have suggested that endotheliopathy may be the common basis for multiple organ failure in sepsis. Under septic conditions, accumulation of proteases accelerates shedding of proteoglycans, such as syndecan-1, from the endothelial surface, resulting in augmented leukocyte adhesion to the vascular wall, enhanced vascular permeability, and intravascular coagulation. The purpose of this study was to determine the potential utility of syndecan-1 as a biomarker linking endotheliopathy to organ failure.Methods: One hundred patients with suspected infections who were admitted to the intensive care unit (ICU) at Kagoshima University Hospital were consecutively enrolled in the study. Serum syndecan-1 levels were measured using an in-house enzyme-linked immunosorbent assay. The difference between serum syndecan-1 levels in 28-day survivors and non-survivors was analyzed by the Mann–Whitney U-test. Receiver-operating characteristics curve analysis with area under the curve calculation was used to quantify the predictive performance of serum syndecan-1 for 28-day mortality. The correlations between serum syndecan-1 and coagulation markers were analyzed by Spearman's rank correlation test.Results: Serum syndecan-1 levels in non-survivors were significantly higher than those in survivors on Day 1 and Day 3 (P < 0.01). Among multiple organ failures, coagulation failure and renal failure were significantly correlated with serum syndecan-1. Spearman's rank correlation test indicated that serum syndecan-1 was weakly but significantly correlated with disseminated intravascular coagulation score (rho = 0.33, P < 0.01). Patients with serum syndecan-1 ≥21.4 ng/mL showed delayed recovery from thrombocytopenia relative to patients with serum syndecan-1 <21.4 ng/mL.Conclusions: Elevated circulating syndecan-1 on the first day of ICU admission was associated with persistent thrombocytopenia and lethal outcome in patients with suspected sepsis.

Lycium barbarum Polysaccharide Antagonizes LPS-Induced Inflammation by Altering the Glycolysis and Differentiation of Macrophages by Triggering the Degradation of PKM2.

Lipopolysaccharide (LPS)-induced inflammation is the leading cause of multiple organ failure in sepsis. Pyruvate kinase 2 (PKM2) is a protein kinase and transcriptional coactivator that plays an important role in glycolysis. Recent studies have confirmed that glycolysis maintains the M1 differentiation and induces immune activation in macrophages. Lycium barbarum polysaccharide (LBP), the main bioactive component of Chinese wolfberry, suppresses glycolysis and inflammation. Here, RAW264.7 macrophages were treated with LBP for evaluating its effects against LPS-induced inflammation. The differentiation of M1/M2 macrophages was assessed by flow cytometry for assessing the cell surface markers, CD86 and CD206. The enrichment of hypoxia inducible factor (HIF)-1α and ubiquitin in the PKM2 protein complex was determined by co-immunoprecipitation. LBP suppressed LPS-induced glycolysis, differentiation of M1 macrophages, and the production of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and high mobility group (HMG) 1 proteins. The suppressive effects of LBP were similar to those of PKM2 knockdown, but were abolished by the overexpression of PKM2. LPS elevated the mRNA and protein levels of PKM2. LBP reduced the LPS-induced expression of PKM2 protein, but had no effects on the expression of PKM2 mRNA. LPS inhibited the ubiquitination of PKM2, probably by downregulating the expression of ubiquitin ligases, including Nedd4L, Nedd4, and Gnb2. LBP interfered with the inhibition of PKM2 ubiquitination by upregulating the expression of Nedd4L, Nedd4, and Gnb2. In conclusion, LBP suppressed the LPS-induced inflammation by altering glycolysis and the M1 differentiation of macrophages. The effects of LBP were mediated by the downregulation of PKM2 via enhanced ubiquitination.

Melatonin Alleviates Cardiac Dysfunction Via Increasing Sirt1-Mediated Beclin-1 Deacetylation and Autophagy During Sepsis.

Cardiac dysfunction is a major cause leading to multiple organ failure in sepsis. Beclin-1-dependent autophagy has been evidenced to exert protective effects on hearts in sepsis. However, the mechanisms on how Beclin-1 and autophagy are regulated remains enigmatic. To explore the detailed mechanisms controlling Beclin-1-dependent autophagy in septic heart and whether melatonin could protect against sepsis via regulating cardiac autophagy, adult Sprague-Dawley (SD) rats were subjected to cecal ligation and puncture (CLP) to induce sepsis. Rats were intraperitoneally administrated with 30 mg/kg melatonin within 5-min post-CLP surgery. Our data showed that sepsis induced Becline-1 acetylation and inhibited autophagy in hearts, resulting in impaired cardiac function. However, melatonin treatment facilitated Beclin-1 deacetylation and increased autophagy in septic hearts, thus improved cardiac function. Moreover, melatonin increased the expression and activity of Sirtuin 1 (Sirt1), and inhibition of Sirt1 abolished the protective effects of melatonin on Beclin-1 deacetylation and cardiac function. In conclusion, increased Beclin-1 acetylation was involved in impaired autophagy in septic hearts, while melatonin contributed to Beclin-1 deacetylation via Sirt1, leading to improved autophagy and cardiac function in sepsis. Our study sheds light on the important role of Beclin-1 acetylation in regulating autophagy in sepsis and suggests that melatonin is a potential candidate drug for the treatment of sepsis.

Calpain Activation and Organ Failure in Sepsis: Molecular Insights and Therapeutic Perspectives.

Sepsis is a severe systemic response to infection; its ensuing organ failure commonly portends an unfavorable prognosis. Despite the fact that sepsis has been studied for decades, the molecular mechanisms underlying sepsis-induced organ dysfunction remain elusive and more complex than previously thought, and effective therapies are extremely limited. Calpain is a type of calcium-dependent cysteine protease that includes dozens of isoforms. Calpain, as well as its endogenous-specific inhibitor calpastatin, have been implicated in the pathogenesis of sepsis-induced organ dysfunction. Further, there is an accumulating body of evidence supporting the beneficial effect of calpain inhibition or regulation on multiple organ failure in sepsis. Better understanding of the underlying molecular mechanisms is helpful in the development of calpain/calpastatin-targeted therapeutic strategies to protect against sepsis-induced organ injury. The aim of this review is to summarize the recent literature and evidence surrounding the role of the calpain/calpastatin system in the process of organ dysfunction caused by sepsis-including regulation of cell death, modulation of inflammatory response, and disruption of critical proteins-to provide guidance for future research and therapy development.

Monocyte upregulation of podoplanin during early sepsis induces complement inhibitor release to protect liver function.

Multiple organ failure in sepsis is a progressive failure of several interdependent organ systems. Liver dysfunction occurs early during sepsis and is directly associated with patient death; however, the underlying mechanism of liver dysfunction is unclear. Platelet transfusion benefits patients with sepsis, and inhibition of complement activation protects liver function in septic animals. Herein, we explored the potential link between platelets, complement activation, and liver dysfunction in sepsis. We found that deletion of platelet C-type lectin-like receptor 2 (CLEC-2) exacerbated liver dysfunction in early sepsis. Platelet CLEC-2-deficient mice exhibited higher complement activation, more severe complement attack in the liver, and lower plasma levels of complement inhibitors at early time points after E. coli infection. Circulating monocytes expressed the CLEC-2 ligand podoplanin in early sepsis, and podoplanin binding induced release of complement inhibitors from platelets. Injection of complement inhibitors released from platelets reduced complement attack and attenuated liver dysfunction in septic mice. These findings indicate a new function of platelets in the regulation of complement activation during sepsis.

NMR-based metabolomics approach reveals effects of antioxidant nutrients in sepsis-induced changes in rat liver injury

Oxidative stress and the production of intracellular reactive oxygen species (ROS) have been implicated in the pathogenesis of sepsis. In excess, oxidative stress is not deemed an unbalanced biochemical reaction in the critically ill rats, but it is a key pathological factor in driving systemic inflammatory response that can result in multiple organ failure in sepsis. Thus, we aimed to explore whether antioxidant nutrients could reduce or delay the oxidative stress condition of sepsis rats, and then play a prospective role in the oxidative stress condition of critical disease. In this investigation, the ability of exogenous and endogenous antioxidant nutrients (ascorbate, taurine and glutathione) to prevent sepsis-induced changes in liver injury was examined using a rat model of sepsis induced by cecal ligation and puncture (CLP), and the underlying mechanisms were also investigated. The effects of three antioxidants on sepsis were assessed based on biochemical assays in combination with an NMR-based metabolomics approach and correlation network analysis. Our results suggested that ascorbate, taurine and glutathione had broadly similar protective effects on reducing oxidative stress. Compared with CLP rats, antioxidant-treated rats exhibited alleviated (P<.05) organ dysfunction and improved liver pathology. Moreover, taurine showed a better efficacy compared with ascorbate and glutathione, evidenced by significantly reversed metabolomics profiles toward normal state. Under conditions of sepsis, antioxidants suppressed inflammatory responses by restraining key signaling pathways, including the redox-sensitive transcription factor pathways of NF-κB and MAPK. Collectively, our findings suggested that antioxidant nutrients exerted beneficial effects on septic rats via protecting mitochondrial.

Investigation of the Mechanism of Shengmai Injection on Sepsis by Network Pharmacology Approaches.

Shengmai injection (SMI) contains Ginsen Radix et Rhizoma Rubra, Ophiopogon japonicus, and Schisandrae Chinensis Fructus. It is used as a supportive herbal medicine in the management of sepsis, systemic inflammatory response syndrome, and septic or hemorrhagic shock. An UPLC method was established to identify and evaluate SMI fingerprints. Fingerprint similarities of 9 batches of SMI were compared. The network platform, “TCM-components-core targets-key pathways,” was established, and the mechanism of SMI in the treatment of sepsis was investigated. The similarity of 9 batches of SMI fingerprints was greater than 0.91. 44 peaks were selected as the common peaks, of which 11 peaks were identified. KEGG functional pathway analysis showed SMI was mainly involved in the pathways of cancer, cell cycle, and p53 signaling, suggesting SMI protects multiple organs via regulating immunity, inflammation, apoptosis, and energy metabolism. GO enrichment analysis showed active SMI components regulated various biological processes and altered the pathophysiology of sepsis. The interplays between SMI and multiple energy metabolism signaling cascades confer protection from life-threatening multiple organ failure in sepsis.

The Effect of Microbial Metabolites on the Functions of Mitochondria in Acidosis and Deficiency of the Substrates of Oxidation

Mitochondrial dysfunction is the main factor in the development of multiple organ failure in sepsis. The role of microbial metabolites in the induction of mitochondrial dysfunction was studied in this work. The effect of phenolic acids of microbial origin on the functions of mitochondria in acidosis and deficiency of the substrate of oxidation accompanying the development of sepsis was investigated. These conditions considerably enhanced the effects of benzoic, phenylpropanoic, phenylpropionic, and phenylacetic acids on the induction of the mitochondrial pore, oxidation of NADH, and oxidative phosphorylation in isolated liver mitochondria. The deficiency of the substrate of oxidation was the most effective factor that enhanced the effect of phenolic acids. Preincubation of mitochondria with phenolic acids in the absence of the substrate of oxidation was accompanied by a significant inhibition of the dehydrogenases of the tricarboxylic acid cycle. The obtained data indicate a potential role of phenolic acids of microbial origin in the development of mitochondrial dysfunction in inflammation and sepsis.

A Comparative Review of Neutrophil Extracellular Traps in Sepsis.

Sepsis is the leading cause of critical illness and mortality in human beings and animals. Neutrophils are the primary effector cells of innate immunity during sepsis. Besides degranulation and phagocytosis, neutrophils also release neutrophil extracellular traps (NETs), composed of cell-free DNA, histones, and antimicrobial proteins. Although NETs have protective roles in the initial stages of sepsis, excessive NET formation has been found to induce thrombosis and multiple organ failure in murine sepsis models. Since the discovery of NETs nearly a decade ago, many investigators have identified NETs in various species. However, many questions remain regarding the exact mechanisms and fate of neutrophils following NET formation. In humans and mice, platelet-neutrophil interactions via direct binding or soluble mediators seem to play an important role in mediating NET formation during sepsis. Preliminary data suggest that these interactions may be species dependent. Regardless of these differences, there is increasing evidence in human and veterinary medicine suggesting that NETs play a crucial role in the pathogenesis of intravascular thrombosis and multiple organ failure in sepsis. Because the outcome of sepsis is highly dependent on early recognition and intervention, detection of NETs or NET components can aid in the diagnosis of sepsis in humans and veterinary species. In addition, the use of novel therapies such as deoxyribonuclease and non-anticoagulant heparin to target NET components shows promising results in murine septic models. Much work is needed in translating these NET-targeting therapies to clinical practice.

Impact of lipid modulation on the intestinal microcirculation in experimental sepsis

It has been observed, that patients who were treated medically for dyslipoproteinemia had a potentially lower risk of complications during infection and sepsis, regarding both morbidity and mortality. Aim of this study in experimental sepsis was to elucidate the impact of lipid metabolism modulation by simvastatin, HDL, or bezafibrate, respectively, on the intestinal microcirculation which plays a crucial role in the development of multiple organ failure in sepsis. Experimental sepsis was induced in Lewis rats by intravenous lipopolysaccharide (LPS) administration. Animals were treated with simvastatin, HDL or bezafibrate. By means of intestinal intravital microscopy (IVM), the inflammatory response in the microcirculation was studied by leukocyte adherence assessment (LA) and functional capillary density (FCD) measurements. In addition, plasma levels of pro-inflammatory cytokines were determined.Bezafibrate treatment led to a reduction in leukocyte adherence, improved functional capillary density (FCD), and a reduction in interleukin-1α (IL-1α), tumour necrosis factor α (TNF-α) and granulocyte macrophage colony stimulating factors (GM-CSF) plasma levels in experimental sepsis.Contrary to this, the administration of HDL increased leukocyte adherence as well as the number of rolling leukocytes. Only IL-1α plasma levels were decreased by HDL. No significant changes were observed following simvastatin treatment.In summary, only bezafibrate showed anti-inflammatory effects in endotoxemia. This effect cannot be explained by the HDL-enhancing effect of the bezafibrate, since the direct administration of HDL showed opposite effects. Bezafibrate induced reduction of inflammation in sepsis should be investigated in further studies.

О роли ароматических микробных метаболитов

Интеграция метаболизма макроорганизма и его микробиоты, обеспечивающая в норме симбиоз и саногенез, нарушается при заболеваниях, травме, критическом состоянии, и вектор взаимодействия может изменяться в пользу прокариотов по принципу «метаболиты бактерий - против хозяина». Анализ литературы показал, что, с одной стороны, имеется живой интерес к ароматическим микробным метаболитам, с другой - отсутствует четкое представление об их роли в организме человека. Публикации, касающиеся ряда ароматических микробных метаболитов (фенилкарбоновых кислот, ФКК), как правило, не связаны между собой по тематике и направлены на решение тех или иных прикладных задач в разных областях биологии и медицины. Цель обзора - анализ информации о происхождении, биологических эффектах ФКК в экспериментах in vitro и in vivo , и клинических наблюдениях. Обобщая результаты приведенных в обзоре исследований на клеточном, субклеточном и молекулярном уровнях, логично предположить участие ароматических микробных метаболитов в патогенезе полиорганной недостаточности при сепсисе. Наиболее перспективным для раскрытия роли ароматических микробных метаболитов представляется изучение механизмов вторичной почечной недостаточности и септической энцефалопатии. Важным направлением для будущих исследований является изучение влияния продуктов микробной биодеградации ароматических соединений на развитие диссеминированного внутрисосудистого свертывания крови, артериальной гипотензии и септического шока. Результаты дальнейших исследований будут иметь не только фундаментальное значение, но и обогатят практическую медицину новыми диагностическими и лечебными технологиями. Significant increases in blood concentrations of some aromatic metabolites (phenylcarboxylic acids, PhCAs) in patients with sepsis have been previously shown. Enhanced bacterial biodegradation of aromatic compounds has been demonstrated to considerably contribute to this process. Integration of macroorganism metabolism and its microbiota, which provides normal symbiosis and sanogenesis, is disturbed in diseases, trauma, and critical conditions. Direction of this interaction may change in favor of prokaryotes according to the principle, “bacterial metabolites are against the host”. Analysis of literature showed a particular interest of many investigators to aromatic microbial metabolites. However, there is no clear understanding of their role in the human body. Publications on PhCAs are generally not thematically interrelated and usually focus on solving applied tasks in different fields of biology and medicine. The aim of this work was to consolidate existing information about origin and biological effects of PhCAs in in vitro / in vivo experiments and some clinical findings. The presented summary of reported data from studies performed at cellular, sub-cellular, and molecular levels suggests participation of aromatic microbial metabolites in the pathogenesis of multiple organ failure in sepsis. Studying mechanisms of secondary renal failure and septic encephalopathy is most promising for discovering the function of aromatic microbial metabolites. Effects of microbial biodegradation products of aromatic substances on development of disseminated intravascular coagulation, hypotension, and septic shock are an important challenge for future studies. Results of further investigations will be not only fundamental, but will also enrich medical practice with new diagnostic and therapeutic technologies.

Parenteral Succinate Reduces Systemic ROS Production in Septic Rats, but It Does Not Reduce Creatinine Levels.

In sepsis, reactive oxygen species (ROS) production is increased. This process takes place mainly within the electron transport chain. ROS production is part of the pathophysiology of multiple organ failure in sepsis. Succinate yields Dihydroflavine-Adenine Dinucleotide (FADH2), which enters the chain through complex II, avoiding complex I, through which electrons are lost. The aim of this work is to determine if parenteral succinate reduces systemic ROS production and improves kidney function. Rats with cecal ligation and puncture were used as model of sepsis, and 4 groups were made: Control group; Succinate group, which only received parenteral succinate; Sepsis group; and Sepsis which received parenteral succinate. Systemic ROS are measured 24 hours after the procedure. Rats subjected to cecal puncture treated with succinate had less systemic ROS than Septic untreated rats (p = 0.007), while there were no differences in creatinine levels (p = 0.07). There was no correlation between creatinine and systemic ROS levels (p = 0.3). We concluded that parenteral succinate reduces ROS levels, but it does not reduce creatinine levels. Since there is no correlation between both levels, the processes would not be related.

Lipopolysaccharide-induced neutrophil extracellular trap formation in canine neutrophils is dependent on histone H3 citrullination by peptidylarginine deiminase

Neutrophils release neutrophil extracellular traps (NETs), which are extracellular chromatin decorated with histones and antimicrobial proteins. Although known for antimicrobial properties, overzealous production of NETs (NETosis) may lead to cytotoxicity and multiple organ failure in sepsis. Pathogen-induced NETosis has been extensively studied in mice but its importance in dogs remains largely unknown. This study sought to characterize in vitro NETosis induced by E.coli LPS, including assessing the role of peptidylarginine deiminase (PAD) in canine NETosis. Neutrophils (1×106 cells/ml) from healthy dogs were isolated and treated with 100μg/ml LPS, 100nM phorbol 12-myristate 13-acetate (PMA), or buffer for either 90 or 180min. NETs were assessed using fluorescence microscopy of living neutrophils and immunofluorescent microscopy. Supernatant and cellular debris were purified and cell-free DNA was quantified by spectrophotometry. The role of PAD was assessed by treating LPS- and PMA-activated neutrophils with 50, 100 or 200μM of the PAD inhibitor, Cl-amidine. In vitro NETosis was characterized by co-localization of cell-free DNA, citrullinated histone H3, and myeloperoxidase. LPS stimulation resulted in intracellular citrullination of histone H3. Compared to PMA chemically-induced NETosis, LPS resulted in smaller NETs with less extracellular citrullinated histone H3. Cl-amidine decreased citrullination of histones and NET production in either LPS- or PMA-stimulated neutrophils demonstrating that neutrophil PAD is essential for these cellular processes.

Survival, bacterial clearance and thrombocytopenia are improved in polymicrobial sepsis by targeting nuclear transport shuttles.

The rising tide of sepsis, a leading cause of death in the US and globally, is not adequately controlled by current antimicrobial therapies and supportive measures, thereby requiring new adjunctive treatments. Severe microvascular injury and multiple organ failure in sepsis are attributed to a “genomic storm” resulting from changes in microbial and host genomes encoding virulence factors and endogenous inflammatory mediators, respectively. This storm is mediated by stress-responsive transcription factors that are ferried to the nucleus by nuclear transport shuttles importins/karyopherins. We studied the impact of simultaneously targeting two of these shuttles, importin alpha 5 (Imp α5) and importin beta 1 (Imp β1), with a cell-penetrating Nuclear Transport Modifier (NTM) in a mouse model of polymicrobial sepsis. NTM reduced nuclear import of stress-responsive transcription factors nuclear factor kappa B, signal transducer and activator of transcription 1 alpha, and activator protein 1 in liver, which was also protected from sepsis-associated metabolic changes. Strikingly, NTM without antimicrobial therapy improved bacterial clearance in blood, spleen, and lungs, wherein a 700-fold reduction in bacterial burden was achieved while production of proinflammatory cytokines and chemokines in blood plasma was suppressed. Furthermore, NTM significantly improved thrombocytopenia, a prominent sign of microvascular injury in sepsis, inhibited neutrophil infiltration in the liver, decreased L-selectin, and normalized plasma levels of E-selectin and P-selectin, indicating reduced microvascular injury. Importantly, NTM combined with antimicrobial therapy extended the median time to death from 42 to 83 hours and increased survival from 30% to 55% (p = 0.022) as compared to antimicrobial therapy alone. This study documents the fundamental role of nuclear signaling mediated by Imp α5 and Imp β1 in the mechanism of polymicrobial sepsis and highlights the potential for targeting nuclear transport as an adjunctive therapy in sepsis management.

Celecoxib administration reduced mortality, mesenteric hypoperfusion, aortic dysfunction and multiple organ injury in septic rats.

The cyclooxygenase (COX)-2 overexpression is associated with vascular injury and multiple organ failure in sepsis. However, constitutive COX-1 and basal COX-2 expressions have physiological effects. We aimed to investigate the effects of partial and selective COX-2 inhibition without affecting constitutive COX-1 and basal COX-2 activities by celecoxib on mesenteric artery blood flow (MABF), vascular reactivity, oxidative and inflammatory injuries, and survival in septic rats accomplished by cecal ligation and puncture (CLP). Wistar rats were allocated into Sham, CLP, Sham+celecoxib, CLP+celecoxib subgroups. 2h after Sham and CLP operations, celecoxib (0.5mg/kg) or vehicle (saline; 1mL/kg) was administered orally to rats. 18h after drug administrations, MABF and responses of isolated aortic rings to phenylephrine were measured. Tissue samples were obtained for biochemical and histopathological examinations. Furthermore, survival rate was monitored throughout 96h. Celecoxib ameliorated mesenteric hypoperfusion and partially improved aortic dysfunction induced by CLP. Survival rate was%0 at 49th h in CLP group, but in CLP+celecoxib group it was 42.8% at the end of 96h. Serum AST, ALT, LDH, BUN, Cr and inflammatory cytokine (tumor necrosis factor-alpha, interleukin-1 beta and interleukin-6) levels were increased in CLP group that were prevented by celecoxib. The decreases in liver and spleen glutathione levels and the increases in liver, lung, spleen and kidney malondialdehyde levels in CLP group were blocked by celecoxib. The histopathological protective effects of celecoxib on organ injury due to CLP were also observed. Celecoxib has protective effects on sepsis due to its preservative effects on mesenteric perfusion, aortic function and its anti-inflammatory and antioxidative effects.

Alert cell strategy in SIRS-induced vasculitis: sepsis and endothelial cells.

Sepsis refers to systemic inflammatory response syndrome and organ failure resulting from infection. Inflammatory receptors (e.g., Toll-like receptors and nucleotide oligomerization domain) recognize bacterial components as inflammatory ligands. These are expressed not only in leukocytes but also in major organs and vascular endothelial cells. “Alert cell” is defined as the cell that expresses the inflammatory receptor and intracellular signaling system to produce inflammatory mediators such as inflammatory cytokines, chemokines, nitric oxide, and prostanoids in organs and the vasculature. NF-κB and AP-1, which are the transcriptional factors of these inflammatory molecules, are important regulators of multiple organ failure in sepsis and systemic inflammation. The vascular endothelial injury would induce multiple organ failure as tissue ischemia and organ death. Drug discovery targeted at alert cells holds a promise for therapy of inflammation including sepsis.