Hallmark Of Sepsis Research Articles

Association between cytokines, nitric oxide, hemodynamic and microcirculation in a porcine model of sepsis

Systemic inflammation and hemodynamic or microvascular alterations are a hallmark of sepsis and play a role in organs hypoperfusion and dysfunction. Pimobendan, an inodilator agent, could be an interesting option for inotropic support and microcirculation preservation during shock. The objectives of this study were to evaluate effect of pimobendan on cytokine and nitric oxide (NO) release and investigate whether changes of macro and microcirculation parameters are associated with the release of cytokines and NO in pigs sepsis model. After circulatory failure, induced by intravenous inoculation of live Pseudomonas aeruginosa, eight animals were treated with pimobendan and eight with placebo.Pimobendan did not affect cytokines secretion (TNF-α, IL-6 and IL-10), but decreased time-dependently NO release. Data of macro and microcirculation parameters, NO and TNF- α recorded at the time of circulatory failure (Thypotension) and the time maximum of production cytokines was used for analyses. A positive correlation was observed between TNF-α and cardiac index (r = 0.55, p = 0.03) and a negative with systemic vascular resistance (r = −0.52, p = 0.04). Positive correlations were seen both between IL-10, 30 min after resuscitation (T30min), and systolic arterial pressure (r = 0.57, p = 0.03) and cardiac index (r = 0.67, p = 0.01), and also between IL-6, taken 2 h after resuscitation and systolic arterial pressure (r = 0.53, p = 0.04). Negative correlations were found between IL-10 and lactate, measured resuscitation time (r = −0.58, p = 0.03). Regarding microcirculation parameters, we observed a positive correlation between IL-6 and IL-10 with the microvascular flow index (r = 0.52, p = 0.05; r = 0.84, p = 0.0003) and a negative correlation with the heterogeneity index with TNF-α and IL-10 (r = −0.51, p = 0.05; r = −0.74, p = 0.003) respectively. NO derivatives showed a positive correlation with temperature gradient (r = 0.54, p = 0.04).Pimobendan did not show anti-inflammatory effects in cytokines release. Our results also, suggest changes of macro- and microcirculation are associated mainly with low levels of IL-10 in sepsis.

Associations of tissue factor and tissue factor pathway inhibitor with organ dysfunctions in septic shock

Coagulopathy, microvascular alterations and concomitant organ dysfunctions are hallmarks of sepsis. Attempts to attenuate coagulation activation with an inhibitor of tissue factor (TF), i.e. tissue factor pathway inhibitor (TFPI), revealed no survival benefit in a heterogenous group of sepsis patients, but a potential survival benefit in patients with an international normalized ratio (INR) < 1.2. Since an increased TF/TFPI ratio determines the procoagulant activity specifically on microvascular endothelial cells in vitro, we investigated whether TF/TFPI ratio in blood is associated with INR alterations, organ dysfunctions, disseminated intravascular coagulation (DIC) and outcome in septic shock. Twenty-nine healthy controls (HC) and 89 patients with septic shock admitted to a tertiary ICU were analyzed. TF and TFPI in blood was analyzed and related to organ dysfunctions, DIC and mortality. Patients with septic shock had 1.6-fold higher levels of TF and 2.9-fold higher levels of TFPI than HC. TF/TFPI ratio was lower in septic shock compared to HC (0.003 (0.002–0.005) vs. 0.006 (0.005–0.008), p < 0.001). Non-survivors had higher TFPI levels compared to survivors (43038 (29354–54023) vs. 28041 (21675–46582) pg/ml, p = 0.011). High TFPI levels were associated with acute kidney injury, liver dysfunction, DIC and disease severity. There was a positive association between TF/TFPI ratio and troponin T (b = 0.531 (0.309–0.754), p < 0.001). A high TF/TFPI ratio is exclusively associated with myocardial injury but not with other organ dysfunctions. Systemic TFPI levels seem to reflect disease severity. These findings point towards a pathophysiologic role of TF/TFPI in sepsis-induced myocardial injury.

The effects of resuscitation with different plasma products on endothelial permeability and organ injury in a rat pneumosepsis model

BackgroundEndothelial injury and permeability are a hallmark of sepsis. Initial resuscitation of septic patients with crystalloids is associated with aggravation of endothelial permeability, which may be related either to low protein content or to volume. We investigated whether initial resuscitation with different types of plasma or albumin decreases endothelial dysfunction and organ injury in a pneumosepsis rat model compared to the same volume of crystalloids.Study design and methodsSprague–Dawley rats were intratracheally inoculated with Streptococcus pneumoniae. Twenty-four hours after inoculation, animals were randomized to 2 control groups and 5 intervention groups (n = 11 per group) to receive resuscitation with a fixed volume (8 mL/kg for 1 h) of either Ringer’s Lactate, 5% human albumin, fresh frozen plasma derived from syngeneic donor rats (rFFP), human-derived plasma (hFFP) or human-derived solvent detergent plasma (SDP). Controls were non-resuscitated (n = 11) and healthy animals. Animals were sacrificed 5 h after start of resuscitation (T = 5). Pulmonary FITC-dextran leakage as a reflection of endothelial permeability was used as the primary outcome.ResultsInoculation with S. Pneumoniae resulted in sepsis, increased median lactate levels (1.6–2.8 mM, p < 0.01), pulmonary FITC-dextran leakage (52–134 µg mL−1, p < 0.05) and lung injury scores (0.7–6.9, p < 0.001) compared to healthy controls. Compared to animals receiving no resuscitation, animals resuscitated with rFFP had reduced pulmonary FITC leakage (134 vs 58 µg/mL, p = 0.011). However, there were no differences in any other markers of organ or endothelial injury. Resuscitation using different human plasma products or 5% albumin showed no differences in any outcome.ConclusionsResuscitation with plasma did not reduce endothelial and organ injury when compared to an equal resuscitation volume of crystalloids. Rat-derived FFP may decrease pulmonary leakage induced by shock.

Dual Role of Extracellular Vesicles in Sepsis-Associated Kidney and Lung Injury

Extracellular vesicles form a complex intercellular communication network, shuttling a variety of proteins, lipids, and nucleic acids, including regulatory RNAs, such as microRNAs. Transfer of these molecules to target cells allows for the modulation of sets of genes and mediates multiple paracrine and endocrine actions. EVs exert broad pro-inflammatory, pro-oxidant, and pro-apoptotic effects in sepsis, mediating microvascular dysfunction and multiple organ damage. This deleterious role is well documented in sepsis-associated acute kidney injury and acute respiratory distress syndrome. On the other hand, protective effects of stem cell-derived extracellular vesicles have been reported in experimental models of sepsis. Stem cell-derived extracellular vesicles recapitulate beneficial cytoprotective, regenerative, and immunomodulatory properties of parental cells and have shown therapeutic effects in experimental models of sepsis with kidney and lung involvement. Extracellular vesicles are also likely to play a role in deranged kidney-lung crosstalk, a hallmark of sepsis, and may be key to a better understanding of shared mechanisms underlying multiple organ dysfunction. In this review, we analyze the state-of-the-art knowledge on the dual role of EVs in sepsis-associated kidney/lung injury and repair. PubMed library was searched from inception to July 2022, using a combination of medical subject headings (MeSH) and keywords related to EVs, sepsis, acute kidney injury (AKI), acute lung injury (ALI), and acute respiratory distress syndrome (ARDS). Key findings are summarized into two sections on detrimental and beneficial mechanisms of actions of EVs in kidney and lung injury, respectively. The role of EVs in kidney-lung crosstalk is then outlined. Efforts to expand knowledge on EVs may pave the way to employ them as prognostic biomarkers or therapeutic targets to prevent or reduce organ damage in sepsis.

BACH1-Hemoxygenase-1 axis regulates cellular energetics and survival following sepsis

Sepsis is a complex disease due to dysregulated host response to infection. Oxidative stress and mitochondrial dysfunction leading to metabolic dysregulation are among the hallmarks of sepsis. The transcription factor NRF2 (Nuclear Factor E2-related factor2) is a master regulator of the oxidative stress response, and the NRF2 mediated antioxidant response is negatively regulated by BTB and CNC homology 1 (BACH1) protein. This study tested whether Bach1 deletion improves organ function and survival following polymicrobial sepsis induced by cecal ligation and puncture (CLP). We observed enhanced post-CLP survival in Bach1−/− mice with a concomitantly increased liver HO-1 expression, reduced liver injury and oxidative stress, and attenuated systemic and tissue inflammation. After sepsis induction, the liver mitochondrial function was better preserved in Bach1−/− mice. Furthermore, BACH1 deficiency improved liver and lung blood flow in septic mice, as measured by SPECT/CT. RNA-seq analysis identified 44 genes significantly altered in Bach1−/− mice after sepsis, including HMOX1 and several genes in lipid metabolism. Inhibiting HO-1 activity by Zinc Protoporphyrin-9 worsened organ function in Bach1−/− mice following sepsis. We demonstrate that mitochondrial bioenergetics, organ function, and survival following experimental sepsis were improved in Bach1−/− mice through the HO-1-dependent mechanism and conclude that BACH1 is a therapeutic target in sepsis.

Serum vimentin predicts mortality in pediatric severe sepsis: A prospective observational study

ObjectivesVascular hyperpermeability by loss of endothelial barrier integrity is a hallmark of sepsis. Vimentin is involved in the regulation of the endothelial function and inflammatory response. However, the serum level of vimentin and its clinical relevance in pediatric severe sepsis (PSS) remain unknown. MethodsWe conducted a prospective study of PSS cases who were admitted to the pediatric intensive care unit (PICU) from January 2018 to December 2020. ResultsA total of 108 patients with PSS with a median age of 19.5 month were enrolled. The hospital mortality rate was 19.44% (21/108). Comparing with healthy controls, serum vimentin levels on PICU admission were significantly higher in patients with PSS (P < 0.001). The area under the ROC curve for vimentin to predict the hospital mortality was 0.712 (95% CI: 0.578–846) with a sensitivity of 71.43% and a specificity of 70.11%. Moreover, hospital mortality was significantly higher in patients with vimentin level over the cutoff value of 24.53 ng/ml than in patients with vimentin level below 24.53 ng/ml (P < 0.001). ConclusionsSerum vimentin level as an indicator of endothelial injury is associated with the prognosis of PSS, and serum vimentin level ≥24.53 ng/ml on PICU admission predicts high risk for hospital mortality in PSS.

Abstract 330: Kinin B1r Inhibitor Prevents Sepsis-induced Cardiac Dysfunction And Promotes Survival In Mice

Introduction: Hyperpermeability of the microvascular barrier and the resulting capillary leakage are hallmarks of sepsis. B1R has been proposed to be a therapeutic target for sepsis-induced microvascular hyperpermeability and multiorgan failure. However, its direct role in regulating of cardiac function during severe sepsis remains poorly characterized. Hypothesis: We hypothesized that B1R inhibition can protect against sepsis-induced cardiac dysfunction and improve survival. Methods and Results: To address the hypothesis, we pre-treated mice with either vehicle (control) or a specific B1R antagonist B6929via subcutaneous injection then subjected them to 40% cecal ligation and puncture (CLP) to induce polymicrobial sepsis. Serum levels of IL-6 and TNFα increased significantly within 4 hours post-CLP in the controls. However, B1R antagonist treatment abolished CLP-induced expressions of IL-6 and TNFα by 70% and 30%, respectively. B1R antagonist also protected mice from sepsis-induced organ failure—as highlighted by the lowered increase in MSS score over the 24-h post-CLP—resulting in significant improvement in survival rate (P&lt;0.05). In-vivo cardiac vascular permeability assessed using the Miles assay further demonstrated that B1R inhibition prevented sepsis-induced cardiac microvascular leakage and edema. Similar improvements were also observed in the liver and kidney. Further study revealed an early cardioprotective effect of B1R inhibitor, as evidenced by the improvement of EF%, FS%, and cardiac output in mice treated with B1R antagonist + CLP vs. CLP alone (p&lt;0.01) from the echocardiogram analyses at 4-6 hours following CLP. Furthermore, mitochondrial H 2 O 2 measurement of the freshly isolated cardiac mitochondria from septic mice also showed that B1R inhibition partially abolished the production of H 2 O 2 . The opening of mPTP was also reduced with B1Ri treatment. Taken together, these findings indicated improvement in cardiac mitochondrial function following B1R inhibitor treatment. Conclusions: Our findings provide novel insights into the pathogenesis of sepsis-induced cardiac mitochondrial dysfunction and heart failure. Inhibition of B1R may be a novel therapeutic strategy for sepsis-associated cardiovascular disease.

Cefiderocol Protects against Cytokine- and Endotoxin-Induced Disruption of Vascular Endothelial Cell Integrity in an In Vitro Experimental Model.

The severe course of bloodstream infections with Gram-negative bacilli can lead to organ dysfunctions and compromise the integrity of the vascular barrier, which are the hallmarks of sepsis. This study aimed to investigate the potential effect of cefiderocol on the barrier function of vascular endothelial cells (vECs) in an in vitro experimental set-up. Human umbilical vein cells (HUVECs), co-cultured with erythrocyte-depleted whole blood for up to 48 h, were activated with tumor necrosis factor-alpha (TNF-α) or lipopolysaccharide (LPS) to induce endothelial damage in the absence or presence of cefiderocol (concentrations of 10, 40 and 70 mg/L). The endothelial integrity was quantified using transendothelial electrical resistance (TEER) measurement, performed at 0, 3, 24 and 48 h after stimulation. Stimulation with TNF-α and LPS increased the endothelial permeability assessed by TEER at 24 and 48 h of co-culture. Furthermore, cefiderocol reduces interleukin-6 (IL-6), interleukin-1β (IL-1β) and TNF-α release in peripheral blood mononuclear cells (PBMCs) following LPS stimulation in a dose-dependent manner. Collectively, the data suggest that cefiderocol may have an influence on the cellular immune response and might support the maintenance of vEC integrity during inflammation associated with infection with Gram-negative bacteria, which warrants further investigations.

Notch Ligand Delta-Like 1 Is Associated With Loss of Vascular Endothelial Barrier Function.

Vascular leakage associated with vascular endothelial cell (vEC) dysfunction is a hallmark of sepsis. Causative for the decreased integrity of the vascular endothelium (vE) is a complex concurrence of pathogen components, inflammation-associated host factors, and the interaction of vECs and activated circulating immune cells. One signaling pathway that regulates the integrity of the vE is the Notch cascade, which is activated through the binding of a Notch ligand to its respective Notch receptor. Recently, we showed that the soluble form of the Notch ligand Delta-like1 (sDLL1) is highly abundant in the blood of patients with sepsis. However, a direct connection between DLL1-activated Notch signaling and loss of vEC barrier function has not been addressed so far. To study the impact of infection-associated sDLL1, we used human umbilical vein cells (HUVEC) grown in a transwell system and cocultured with blood. Stimulation with sDLL1 induced activation as well as loss of endothelial tight structure and barrier function. Moreover, LPS-stimulated HUVEC activation and increase in endothelial cell permeability could be significantly decreased by blocking DLL1-receptor binding and Notch signaling, confirming the involvement of the cascade in LPS-mediated endothelial dysfunction. In conclusion, our results suggest that during bacterial infection and LPS recognition, DLL1-activated Notch signaling is associated with vascular permeability. This finding might be of clinical relevance in terms of preventing vascular leakage and the severity of sepsis.

Azithromycin and Major Adverse Kidney Events in Critically Ill Patients With Sepsis-Associated Acute Kidney Injury.

Sepsis-associated acute kidney injury (SA-AKI) is associated with significant morbidity and mortality. Immune dysregulation is a hallmark of sepsis, with important contributions to organ dysfunction including injury and repair mechanisms in AKI. Macrolide antibiotics, such as azithromycin, have previously demonstrated in preclinical models a myriad of immunomodulatory effects that may benefit critically ill patients with SA-AKI. The aim of this study was to determine if early receipt of azithromycin in SA-AKI is associated with a reduction in major adverse kidney events (MAKE) at hospital discharge. This was a single center, retrospective cohort study of critically ill adult patients with SA-AKI. Early exposure to azithromycin was defined as receipt of one or more doses within 48 h of a hospital admission with SA-AKI. The primary outcome of MAKE assessed at hospital discharge was the composite of death, requirement for kidney replacement therapy, or a decline in estimated glomerular filtration rate of 25% or more. Multivariable logistic regression was used to account for potential confounders in the assessment. Of 737 included patients with SA-AKI, 152 (20.6%) received azithromycin. Patients that received early azithromycin were less likely to experience MAKE at hospital discharge when compared to those patients not receiving azithromycin: 38.8% versus 48.4% (P = 0.035). In multivariable logistic regression, receipt of azithromycin was independently associated with a decreased odds of MAKE at hospital discharge (aOR 0.62, 95% CI 0.41-0.93). Early exposure to azithromycin in SA-AKI is independently associated with lower odds of MAKE at hospital discharge.

Acute Inflammation and Oxidative Stress Induced by Lipopolysaccharide and the Ameliorative Effect of Stingless Bee Honey.

Systemic acute inflammation is the hallmark of sepsis and is associated with multiple organ dysfunction. This study investigated the potential of Stingless Bee Honey (SBH) to suppress lipopolysaccharide (LPS)-induced systemic acute inflammation in rats and to reveal the probable mechanism of action. Rats received 4.6 and 9.2 g/kg SBH for 7 days followed by a single injection of LPS after which blood samples were taken 6h later. LPS induced liver, kidney, heart, and lung injury, were manifested by increased serum transaminases, alkaline phosphatase, creatine kinase, creatinine, and urea, along with multiple histological alterations, particularly leukocyte infiltration. Pro-inflammatory cytokines were elevated in the serum, and NF-κB p65, p38 MAPK, and HMGB-1 were significantly increased in different tissues of LPS-challenged rats. SBH prevented tissue injury, ameliorated pro-inflammatory cytokines, and suppressed NF-κB p65, p38 MAPK, and HMGB-1 in rats that had received LPS. In addition, SBH diminished reactive oxygen species (ROS) production, lipid peroxidation, and oxidative DNA damage, and enhanced glutathione and Nrf2 in LPS-treated rats. SBH prevents systemic acute inflammation by suppressing NF-κB, p38 MAPK, HMGB-1, oxidative stress, and tissue injury in rats. Thus, SBH may represent an effective anti-inflammatory nutraceutical, pending further mechanistic studies.

Modulation of LPS-induced inflammatory cytokine production by a novel glycogen synthase kinase-3 inhibitor

Sepsis is a serious condition that can lead to long-term organ damage and death. At the molecular level, the hallmark of sepsis is the elevated expression of a multitude of potent cytokines, i.e. a cytokine storm. For sepsis involving gram-negative bacteria, macrophages recognize lipopolysaccharide (LPS) shed from the bacteria, activating Toll-like-receptor 4 (TLR4), and triggering a cytokine storm. Glycogen synthase kinase-3 (GSK-3) is a highly active kinase that has been implicated in LPS-induced cytokine production. Thus, compounds that inhibit GSK-3 could be potential therapeutics for sepsis. Our group has recently described a novel and highly selective inhibitor of GSK-3 termed COB-187. In the present study, using THP-1 macrophages, we evaluated the ability of COB-187 to attenuate LPS-induced cytokine production. We found that COB-187 significantly reduced, at the protein and mRNA levels, cytokines induced by LPS (e.g. IL-6, TNF-α, IL-1β, CXCL10, and IFN-β). Further, the data suggest that the inhibition could be due, at least in part, to COB-187 reducing NF-κB (p65/p50) DNA binding activity as well as reducing IRF-3 phosphorylation at Serine 396. Thus, COB-187 appears to be a potent inhibitor of the cytokine storm induced by LPS.

Experience with hemoadsorption (CytoSorb®) in the management of septic shock patients

BACKGROUNDCytokines and inflammatory mediators are the hallmarks of sepsis. Extracorporeal cytokine hemoadsorption devices are the newer clinical support system to overcome the cytokine storm during sepsis.AIMTo retrospectively evaluate the clinical outcomes of patients admitted in intensive care unit with septic shock with different etiologies.METHODSThe laboratory parameters including biomarkers such as procalcitonin, serum lactate and C-reactive protein; and the hemodynamic parameters; mean arterial pressure, vasopressor doses, sepsis scores, cytokine levels and other vital parameters were evaluated. We evaluated these outcomes among survivors and non-survivors.RESULTSOf 100 patients evaluated, 40 patients survived. Post treatment, the vasopressors dosage remarkably decreased though it was not statistically different; 34.15% (P = 0.0816) for epinephrine, 20.5 % for norepinephrine (P = 0.3099) and 51% (P = 0.0678) for vasopressin. In the survivor group, a remarkable reduction of biomarkers levels; procalcitonin (65%, P = 0.5859), C-reactive protein (27%, P = 0.659), serum lactate (27%, P = 0.0159) and bilirubin (43.11%; P = 0.0565) were observed from baseline after CytoSorb® therapy. A significant reduction in inflammatory markers; interleukin 6 and interleukin 10; (87% and 92%, P < 0.0001) and in tumour necrosis factor (24%, P = 0.0003) was also seen. Overall, 28 (28%) patients who were given CytoSorb® therapy less than 48 h after onset of septic shock survived and the maximum duration of stay for 70% of these patients in intensive care unit was less than 15 d.CONCLUSIONCytoSorb® is a safe and well tolerated rescue therapy option in patients with septic shock. However, early (preferably within < 48 h after onset of septic shock) initiation could result in better clinical outcomes. Further randomized trials are needed to define the potential benefits of this new treatment modality.

Optimizing oxygen delivery in sepsis: A review

Multiple organ failure syndrome (MOFS) is a hallmark of sepsis. The continued dysfunction of microvascular perfusion has been implicated as the inciting factor for this. Multiple etiopathological factors are involved in producing this disequilibrium in the demand, supply, and extraction of oxygen as a result of derecruitment of microcirculation. This is further complicated by mitochondrial dysfunction in the form of the inhibition of mitochondrial respiratory chain of enzymes, leading to difficulty in extraction of the oxygen at the cellular level. Eventually, although hemodynamic stability of systemic/macrovascular circulation may have been achieved, the process of deficient and defective delivery of oxygen to the tissues goes on relentlessly. The indicators and monitoring of this process of impairment of oxygen delivery (DO2) have been discussed in this review. In addition, the review also encompasses various therapeutic modalities and their efficacy, based on the evidence. The latest guidelines regarding optimizing the DO2 in sepsis are also included here.

Identification of suitable controls for miRNA quantification in T-cells and whole blood cells in sepsis

Complex immune dysregulation is a hallmark of sepsis. The occurring phases of immunosuppression and hyperinflammation require rapid detection and close monitoring. Reliable tools to monitor patient’s immune status are yet missing. Currently, microRNAs are being discussed as promising new biomarkers in sepsis. However, no suitable internal control for normalization of miRNA expression by qPCR has been validated so far, thus hampering their potential benefit. We here present the first evaluation of endogenous controls for miRNA analysis in human sepsis. Novel candidate reference miRNAs were identified via miRNA microArray. TaqMan qPCR assays were performed to evaluate these microRNAs in T-cells and whole blood cells of sepsis patients and healthy controls in two independent cohorts. In T-cells, U48 and miR-320 proved suitable as endogenous controls, while in whole blood cells, U44 and miR-942 provided best stability values for normalization of miRNA quantification. Commonly used snRNA U6 exhibited worst stability in all sample groups. The identified internal controls have been prospectively validated in independent cohorts. The critical importance of housekeeping gene selection is emphasized by exemplary quantification of imuno-miR-150 in sepsis patients. Use of appropriate internal controls could facilitate research on miRNA-based biomarker-use and might even improve treatment strategies in the future.

A Review on The Protective Effects of Metformin in Sepsis-Induced Organ Failure.

Despite advances in sepsis management, it remains a major intensive-care-unit (ICU) concern. From new prospective, positive effects of metformin, such as anti-oxidant and anti-inflammatory properties are considered potentially beneficial properties for management of septic patients. This article reviewed the potential ameliorative effects of metformin in sepsis-induced organ failure. Information were retrieved from PubMed, Scopus, Embase, and Google Scholar. Multi-organ damage, oxidative stress, inflammatory cytokine stimulation, and altered circulation are hallmarks of sepsis. Metformin exerts its effect via adenosine monophosphate-activated protein kinase (AMPK) activation. It improves sepsis-induced organ failure by inhibiting the production of reactive oxygen species (ROS) and pro-inflammatory cytokines, preventing the activation of transcription factors related to inflammation, decreasing neutrophil accumulation/infiltration, and also maintaining mitochondrial membrane potential. Studies reported the safety of metformin therapeutic doses, with no evidence of lactic acidosis, in septic patients.

Histidine-rich glycoprotein ameliorates endothelial barrier dysfunction through regulation of NF-κB and MAPK signal pathway.

Background and PurposeMicrovascular barrier breakdown is a hallmark of sepsis that is associated with sepsis‐induced multiorgan failure. Histidine‐rich glycoprotein (HRG) is a 75‐kDa plasma protein that was demonstrated to improve the survival of septic mice through regulation of cell shape, spontaneous ROS production in neutrophils, and adhesion of neutrophils to vascular endothelial cells. We investigated HRG's role in the LPS/TNF‐α‐induced barrier dysfunction of endothelial cells in vitro and in vivo and the possible mechanism, to clarify the definitive roles of HRG in sepsis.Experimental ApproachEA.hy 926 endothelial cells were pretreated with HRG or human serum albumin before stimulation with LPS/TNF‐α. A variety of biochemical assays were applied to explore the underlying molecular mechanisms on how HRG protected the barrier function of vascular endothelium.Key ResultsImmunostaining results showed that HRG maintains the endothelial monolayer integrity by inhibiting cytoskeleton reorganization, losses of VE‐cadherin and β‐catenin, focal adhesion kinase degradation, and cell detachment induced by LPS/TNF‐α. HRG also inhibited the cytokine secretion from endothelial cells induced by LPS/TNF‐α, which was associated with reduced NF‐κB activation. Moreover, HRG effectively prevented the LPS/TNF‐α‐induced increase in capillary permeability in vitro and in vivo. Finally, Western blot results demonstrated that HRG prevented the phosphorylation of MAPK family and RhoA activation, which are involved mainly in the regulation of cytoskeleton reorganization and barrier permeability.Conclusions and ImplicationsTaken together, our results demonstrate that HRG has protective effects on vascular barrier function in vitro and in vivo, which may be due to the inhibition of MAPK family and Rho activation.

Cardiovascular Reflexes Control Hemodynamic Responses During LPS‐induced Systemic Inflammation in Conscious Rats

Lipopolysaccharide (LPS)‐induced systemic inflammation (SI) is associated with hypotension, tachycardia, and multiple organs dysfunctions. SI, a hallmark of sepsis can lead to cardiovascular impairment and death. Considering that the nervous system regulates immunity and that cardiovascular reflexes, i.e. baroreflex, chemoreflex, and Bezold‐Jarish reflex, are important regulators of hemodynamic function, we investigated these cardiovascular reflexes control acutely and 24 hours after LPS‐induced SI. We combined cardiovascular recordings, immunofluorescence and molecular approaches in male Wistar rats that received intravenous administration of LPS (1.5 or 2.5 mg.kg−1, CEUA #2017.1.585.58.9). LPS induced hypotension and tachycardia and reduction in baroreflex gain. On the other hand, SI caused no significant impairment in hemodynamic responses to chemoreflex and Bezold‐Jarish reflexes, despite an increased number of activated microglia and IL‐1β levels in the nucleus tractus solitarius. The present data are consistent with the notion that cardiovascular reflexes are kept functional even with central nervous system inflammation. These findings provide insights into the mechanisms that regulate the cardiovascular system during SI and indicate that the improvement of these reflexes responsiveness can be useful for the therapeutic management of sepsis.Support or Funding InformationFAPESP, CAPES and CNPqThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Cardiovascular Insufficiency, Abdominal Sepsis, and Patients' Age Are Associated with Decreased Paraoxonase-1 (PON1) Activity in Critically Ill Patients with Multiple Organ Dysfunction Syndrome (MODS).

Oxidative stress and uncontrolled inflammation are hallmarks of sepsis, leading to organ failure and death. As demonstrated in animal studies, oxidative stress can be alleviated by antioxidant therapies. Paraoxonase-1 (PON1) is a serum-based antioxidant, anti-inflammatory agent, detoxifier, and quorum-sensing factor found to be a prognostic marker in sepsis. However, its associations with multiple organ dysfunction syndrome (MODS), a complication of sepsis and the leading cause of death in the surgical intensive care units (ICU), as well as with specific organ dysfunction, infection site, and invading pathogen remain unknown. Therefore, we measured arylesterase activity of PON1 in 87 individuals (35 with MODS) and related it to the clinical type, organ failure, infection site, pathogens, and hematological and biochemical indices of inflammation at admission to ICU and during a five-day follow-up. Suitability of PON1 and its indices derived from a follow-up as biomarkers in MODS was evaluated as well. MODS was associated with decreased PON1, more so in patients with septic shock, displaying an excellent accuracy as a marker of MODS (91%) and a fair one as a marker in differentiating septic shock from severe sepsis (76%). Decreased admission PON1 accompanied cardiovascular insufficiency (CVI), and, as its marker, PON1 displayed a good accuracy (82%). It was also associated with the abdomen as a site of infection but not with an invading pathogen. In multivariate analysis, 50% of variability in PON1 activity in patients with MODS was explained by the patients' age, CVI, and abdomen as a site of infection. Patients with septic shock, CVI, and abdominal MODS had distinctly different dynamics of PON1 during a follow-up. Mean PON1 activity during the follow-up reflected the associations observed for admission PON1 but was also significantly associated with metabolic dysfunction. Our results show PON1 potential as a biomarker in MODS, particularly as an indicator of CVI.

Sepsis induces long-lasting impairments in CD4+ T-cell responses despite rapid numerical recovery of T-lymphocyte populations.

Massive apoptosis of lymphocytes is a hallmark of sepsis. The resulting immunosuppression is associated with secondary infections, which are often lethal. Moreover, sepsis-survivors are burdened with increased morbidity and mortality for several years after the sepsis episode. The duration and clinical consequences of sepsis induced-immunosuppression are currently unknown. We have used the mouse model of peritoneal contamination and infection (PCI) to investigate the quantitative and qualitative recovery of T lymphocytes for 3.5 months after sepsis with or without IL-7 treatment. Thymic output and the numbers of naive and effector/memory CD4+ and CD8+ lymphocytes quickly recovered after sepsis. IL-7 treatment resulted in an accelerated recovery of CD8+ lymphocytes. Next generation sequencing revealed no significant narrowing of the T cell receptor repertoire 3.5 months after sepsis. In contrast, detailed functional analyses of T helper (Th)-cell responses towards a fungal antigen revealed a significant loss of Th cells. Whereas cytokine production was not impaired at the single cell level, the absolute number of Th cells specific for the fungal antigen was reduced. Our data indicate a clinically relevant loss of pathogen-specific T cell clones after sepsis. Given the small number of naive T lymphocytes specific for a given antigen, this decrement of T cell clones remains undetected even by sensitive methods such as deep sequencing. Taken together, our data are compatible with long lasting impairments in CD4+ T-cell responses after sepsis despite rapid recovery of T lymphocyte populations.