Metabolic Resuscitation Strategies to Prevent Organ Dysfunction in Sepsis

SIRT3 Deficiency Promotes Lung Endothelial Pyroptosis Through Impairing Mitophagy to Activate NLRP3 Inflammasome During Sepsis-Induced Acute Lung Injury

Acute lung injury (ALI) is a major cause of death in bacterial sepsis due to endothelial inflammation and endothelial permeability defects. Mitochondrial dysfunction is recognized as a key mediator in the pathogenesis of sepsis-induced ALI. Sirtuin 3 (SIRT3) is a histone protein deacetylase involved in preservation of mitochondrial function, which has been demonstrated in our previous study. Here, we investigated the effects of SIRT3 deficiency on impaired mitophagy to promote lung endothelial cells (ECs) pyroptosis during sepsis-induced ALI. We found that 3-TYP aggravated sepsis-induced ALI with increased lung ECs pyroptosis and enhanced NLRP3 activation. Mitochondrial reactive oxygen species (mtROS) and extracellular mitochondrial DNA (mtDNA) released from damaged mitochondria could be exacerbated in SIRT3 deficiency, which further elicit NLRP3 inflammasome activation in lung ECs during sepsis-induced ALI. Furthermore, Knockdown of SIRT3 contributed to impaired mitophagy via downregulating Parkin, which resulted in mitochondrial dysfunction. Moreover, pharmacological inhibition NLRP3 or restoration of SIRT3 attenuates sepsis-induced ALI and sepsis severity in vivo. Taken together, our results demonstrated SIRT3 deficiency facilitated mtROS production and cytosolic release of mtDNA by impaired Parkin-dependent mitophagy, promoting to lung ECs pyroptosis through the NLRP3 inflammasome activation, which providing potential therapeutic targets for sepsis-induced ALI.

U-shaped association between serum triglyceride levels and mortality among septic patients: An analysis based on the MIMIC-IV database

BACKGROUND

Sepsis is characterized by upregulated lipolysis in adipose tissue and a high blood triglyceride (TG) level. It is still debated whether serum TG level is related to mortality in septic patients. The aim of this study is to investigate the association between serum TG level and mortality in septic patients admitted to the intensive care unit (ICU).

METHODS

Data from adult septic patients (≥18 years) admitted to the ICU for the first time were obtained from the Multiparameter Intelligent Monitoring in Intensive Care IV (MIMIC-IV) database. The patients' serum TG levels that were measured within the first week after ICU admission were extracted for statistical analysis. The endpoints were 28-day, ICU and in-hospital mortality.

RESULTS

A total of 2,782 septic patients were included. Univariate analysis indicated that the relationship between serum TG levels and the risk of mortality was significantly nonlinear. Both the Lowess smoothing technique and restricted cubic spline analyses revealed a U-shaped association between serum TG levels and mortality among septic patients. The lowest mortality rate was associated with a serum TG level of 300-500 mg/dL. Using 300∼500 mg/dL as the reference range, we found that both hypo-TG (<300 mg/dL) and hyper-TG (≥500 mg/dL) were associated with increased mortality. The result was further adjusted by Cox regression with and without the inclusion of some differential covariates.

CONCLUSIONS

There was a U-shaped association between serum TG and mortality in septic ICU patients. The optimal concentration of serum TG levels in septic ICU patients is 300-500 mg/dL.

HAT therapy for sepsis: A review of the therapeutic rationale and current clinical evaluation status

Vitamin C-based cluster therapy, which involves the combined application of hydrocortisone, vitamin C, and thiamine (HAT), is a recently proposed new treatment option for sepsis on top of conventional treatment. This therapy has a strong theoretical basis, but its clinical efficacy remains inconclusive. This review summarizes the rationale for HAT therapy for sepsis and describes the evaluation of its efficacy in clinical observational studies and randomized controlled trials, with the aim of providing a reference for the future clinical practice application of HAT therapy in sepsis.

Intravenous high-dose vitamin C monotherapy for sepsis and septic shock: A meta-analysis of randomized controlled trials

BACKGROUND

Vitamin C has been used as an adjuvant in the treatment of sepsis and septic shock; however, its role remains controversial. This study aimed to assess the effectiveness of intravenous high-dose vitamin C in sepsis and septic shock patients by meta-analysis.

METHODS

The PubMed, Embase, and Cochrane Library electronic databases were searched to identify relevant studies. The primary outcome was defined as the short-term all-cause mortality rate. Secondary outcomes included duration of vasoactive drug use, intensive care unit length of stay, sequential organ failure assessment scores up to 96 hours after treatment and 90-day mortality. Review Manager version 5.4 was used to perform the meta-analysis. Relative risk and mean differences (MD) with 95% confidence intervals were determined using fixed- or random-effects models.

RESULTS

Eight randomized controlled trials (RCTs) comprising 1394 patients were eligible for assessment. Overall, the pooled results showed that high-dose vitamin C decreased short-term all-cause mortality in patients with sepsis, but no significant differences were observed in patients with septic shock. Additionally, high-dose vitamin C was associated with decreased duration of vasoactive drug use in patients with sepsis, but not in patients with septic shock. However, it did not significantly affect the duration of intensive care unit stay in RCTs of patients with sepsis and septic shock. Additionally, it did not significantly affect sequential organ failure assessment scores 96 hours post-treatment or 90-day mortality.

CONCLUSION

These results suggest that intravenous high-dose vitamin C may improve outcomes in patients with sepsis, but do not benefit patients with septic shock. Further RCTs and other studies should be conducted to determine whether vitamin C should be recommended as an adjunctive sepsis treatment.

Mitochondrial Dysfunction in Bacterial Infections

Mitochondria are critical in numerous cellular processes, including energy generation. Bacterial pathogens target host cell mitochondria through various mechanisms to disturb the host response and improve bacterial survival. We review recent advances in the understanding of how bacteria cause mitochondrial dysfunction through perturbations in mitochondrial cell-death pathways, energy production, mitochondrial dynamics, mitochondrial quality control, DNA repair, and the mitochondrial unfolded protein response. We also briefly highlight possible therapeutic approaches aimed at restoring the host mitochondrial function as a novel strategy to enhance the host response to bacterial infection.

Inflammatory mechanisms and intervention strategies for sepsis-induced myocardial dysfunction

Sepsis-induced myocardial dysfunction (SIMD) is the leading cause of death in patients with sepsis in the intensive care units. The main manifestations of SIMD are systolic and diastolic dysfunctions of the myocardium. Despite our initial understanding of the SIMD over the past three decades, the incidence and mortality of SIMD remain high. This may be attributed to the large degree of heterogeneity among the initiating factors, disease processes, and host states involved in SIMD. Previously, organ dysfunction caused by sepsis was thought to be an impairment brought about by an excessive inflammatory response. However, many recent studies have shown that SIMD is a consequence of a combination of factors shaped by the inflammatory responses between the pathogen and the host. In this article, we review the mechanisms of the inflammatory responses and potential novel therapeutic strategies in SIMD.

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.

Outcomes Associated With Timing of Neurologic Dysfunction Onset Relative to Pediatric Sepsis Recognition

OBJECTIVES

To compare outcomes associated with timing-early versus late-of any neurologic dysfunction during pediatric sepsis.

DESIGN

Secondary analysis of a cross-sectional point prevalence study.

SETTING

A total of 128 PICUs in 26 countries.

PATIENTS

Less than 18 years with severe sepsis on 5 separate days (2013-2014).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients were categorized as having either no neurologic dysfunction or neurologic dysfunction (i.e., present at or after sepsis recognition), which was defined as Glasgow Coma Scale score less than 5 and/or fixed dilated pupils. Our primary outcome was death or new moderate disability (i.e., Pediatric Overall [or Cerebral] Performance Category score ≥3 and change ≥1 from baseline) at hospital discharge, and 87 of 567 severe sepsis patients (15%) had neurologic dysfunction within 7 days of sepsis recognition (61 at sepsis recognition and 26 after sepsis recognition). Primary site of infection varied based on presence of neurologic dysfunction. Death or new moderate disability occurred in 161 of 480 (34%) without neurologic dysfunction, 45 of 61 (74%) with neurologic dysfunction at sepsis recognition, and 21 of 26 (81%) with neurologic dysfunction after sepsis recognition (p < 0.001 across all groups). On multivariable analysis, in comparison with those without neurologic dysfunction, neurologic dysfunction whether at sepsis recognition or after was associated with increased odds of death or new moderate disability (adjusted odds ratio, 4.9 [95% CI, 2.3-10.1] and 10.7 [95% CI, 3.8-30.5], respectively). We failed to identify a difference between these adjusted odds ratios of death or new moderate disability that would indicate a differential risk of outcome based on timing of neurologic dysfunction (p = 0.20).

CONCLUSIONS

In this severe sepsis international cohort, the presence of neurologic dysfunction during sepsis is associated with worse outcomes at hospital discharge. The impact of early versus late onset of neurologic dysfunction in sepsis on outcome remains unknown, and further work is needed to better understand timing of neurologic dysfunction onset in pediatric sepsis.

Physiological roles of hydrogen sulfide in mammalian cells, tissues and organs

H2S belongs to the class of molecules known as gasotransmitters, which also includes nitric oxide (NO) and carbon monoxide (CO). Three enzymes are recognized as endogenous sources of H2S in various cells and tissues: cystathionine g-lyase (CSE), cystathionine β-synthase (CBS) and 3-mercaptopyruvate sulfurtransferase (3-MST). The current article reviews the regulation of these enzymes as well as the pathways of their enzymatic and non-enzymatic degradation and elimination. The multiple interactions of H2S with other labile endogenous molecules (e.g. NO) and reactive oxygen species are also outlined. The various biological targets and signaling pathways are discussed, with special reference to H2S and oxidative posttranscriptional modification of proteins, the effect of H2S on channels and intracellular second messenger pathways, the regulation of gene transcription and translation and the regulation of cellular bioenergetics and metabolism. The pharmacological and molecular tools currently available to study H2S physiology are also reviewed, including their utility and limitations. In subsequent sections, the role of H2S in the regulation of various physiological and cellular functions is reviewed. The physiological role of H2S in various cell types and organ systems are overviewed. Finally, the role of H2S in the regulation of various organ functions is discussed as well as the characteristic bell-shaped biphasic effects of H2S. In addition, key pathophysiological aspects, debated areas, and future research and translational areas are identified A wide array of significant roles of H2S in the physiological regulation of all organ functions emerges from this review.

Repurposing of Clinically Approved Poly-(ADP-Ribose) Polymerase Inhibitors for the Therapy of Sepsis

ABSTRACT

Sepsis' pathogenesis involves multiple mechanisms that lead to a dysregulation of the host's response. Significant efforts have been made in search of interventions that can reverse this situation and increase patient survival. Poly (ADP-polymerase) (PARP) is a constitutive nuclear and mitochondrial enzyme, which functions as a co-activator and co-repressor of gene transcription, thus regulating the production of inflammatory mediators. Several studies have already demonstrated an overactivation of PARP1 in various human pathophysiological conditions and that its inhibition has benefits in regulating intracellular processes. The PARP inhibitor olaparib, originally developed for cancer therapy, paved the way for the expansion of its clinical use for nononcological indications. In this review we discuss sepsis as one of the possible indications for the use of olaparib and other clinically approved PARP inhibitors as modulators of the inflammatory response and cellular dysfunction. The benefit of olaparib and other clinically approved PARP inhibitors has already been demonstrated in several experimental models of human diseases, such as neurodegeneration and neuroinflammation, acute hepatitis, skeletal muscle disorders, aging and acute ischemic stroke, protecting, for example, from the deterioration of the blood-brain barrier, restoring the cellular levels of NAD+, improving mitochondrial function and biogenesis and, among other effects, reducing oxidative stress and pro-inflammatory mediators, such as TNF-α, IL1-β, IL-6, and VCAM1. These data demonstrated that repositioning of clinically approved PARP inhibitors may be effective in protecting against hemodynamic dysfunction, metabolic dysfunction, and multiple organ failure in patients with sepsis. Age and gender affect the response to PARP inhibitors, the mechanisms underlying the lack of many protective effects in females and aged animals should be further investigated and be cautiously considered in designing clinical trials.

Sirt3 Maintains Microvascular Endothelial Adherens Junction Integrity to Alleviate Sepsis-Induced Lung Inflammation by Modulating the Interaction of VE-Cadherin and β-Catenin

Inflammatory injury is a hallmark of sepsis-induced acute respiratory distress syndrome (ARDS)/acute lung injury (ALI). However, the mechanisms underlying inflammatory injury remain obscure. Here, we developed the novel strategy to suppress lung inflammation through maintaining microvascular endothelial barrier integrity. VE-cadherin is the main adherens junction protein that interacts with β-catenin and forms a complex. We found that lung inflammation was accompanied by decreased VE-cadherin expression and increased β-catenin activity in animal models and human pulmonary microvascular endothelial cells (HPMECs), illuminating the relationship among VE-cadherin/β-catenin complex, microvascular endothelial barrier integrity, and inflammation. Furthermore, we showed that the VE-cadherin/β-catenin complex dissociated upon lung inflammation, while Sirt3 promoted the stability of such a complex. Sirt3 was decreased during lung inflammation in vivo and in vitro. Sirt3 deficiency not only led to the downregulation of VE-cadherin but also enhanced the transcriptional activity of β-catenin that further increased β-catenin target gene MMP-7 expression, thereby promoting inflammatory factor COX-2 expression. Sirt3 overexpression promoted VE-cadherin expression, inhibited β-catenin transcriptional activity, strengthened the stability of the VE-cadherin/β-catenin complex, and suppressed inflammation in HPMECs. Notably, Sirt3 deficiency significantly damaged microvascular endothelial barrier integrity and intensified lung inflammation in animal model. These results demonstrated the role of Sirt3 in modulating microvascular endothelial barrier integrity to inhibit inflammation. Therefore, strategies that aim at enhancing the stability of endothelial VE-cadherin/β-catenin complex are potentially beneficial for preventing sepsis-induced lung inflammation.

Sodium Thiosulfate Improves Intestinal and Hepatic Microcirculation Without Affecting Mitochondrial Function in Experimental Sepsis

Introduction

In the immunology of sepsis microcirculatory and mitochondrial dysfunction in the gastrointestinal system are important contributors to mortality. Hydrogen sulfide (H₂S) optimizes gastrointestinal oxygen supply and mitochondrial respiration predominantly via K(ATP)-channels. Therefore, we tested the hypothesis that sodium thiosulfate (STS), an inducer of endogenous H₂S, improves intestinal and hepatic microcirculation and mitochondrial function via K(ATP)-channels in sepsis.

Methods

In 40 male Wistar rats colon ascendens stent peritonitis (CASP) surgery was performed to establish sepsis. Animals were randomized into 4 groups (1: STS 1 g • kg^-1 i.p., 2: glibenclamide (GL) 5 mg • kg^-1 i.p., 3: STS + GL, 4: vehicle (VE) i.p.). Treatment was given directly after CASP-surgery and 24 hours later. Microcirculatory oxygenation (µHBO₂) and flow (µflow) of the colon and the liver were continuously recorded over 90 min using tissue reflectance spectrophotometry. Mitochondrial oxygen consumption in tissue homogenates was determined with respirometry. Statistic: two-way ANOVA + Dunnett´s and Tukey post - hoc test (microcirculation) and Kruskal-Wallis test + Dunn’s multiple comparison test (mitochondria). p < 0.05 was considered significant.

Results

STS increased µHbO₂ (colon: 90 min: + 10.4 ± 18.3%; liver: 90 min: + 5.8 ± 9.1%; p < 0.05 vs. baseline). Furthermore, STS ameliorated µflow (colon: 60 min: + 51.9 ± 71.1 aU; liver: 90 min: + 22.5 ± 20.0 aU; p < 0.05 vs. baseline). In both organs, µHbO₂ and µflow were significantly higher after STS compared to VE. The combination of STS and GL increased colonic µHbO₂ and µflow (µHbO₂ 90 min: + 8.7 ± 11.5%; µflow: 90 min: + 41.8 ± 63.3 aU; p < 0.05 vs. baseline), with significantly higher values compared to VE. Liver µHbO₂ and µflow did not change after STS and GL. GL alone did not change colonic or hepatic µHbO₂ or µflow. Mitochondrial oxygen consumption and macrohemodynamic remained unaltered.

Conclusion

The beneficial effect of STS on intestinal and hepatic microcirculatory oxygenation in sepsis seems to be mediated by an increased microcirculatory perfusion and not by mitochondrial respiratory or macrohemodynamic changes. Furthermore, the effect of STS on hepatic but not on intestinal microcirculation seems to be K(ATP)-channel-dependent.

Metabolic Alterations in Sepsis

Sepsis is defined as “life-threatening organ dysfunction caused by a dysregulated host response to infection”. Contrary to the older definitions, the current one not only focuses on inflammation, but points to systemic disturbances in homeostasis, including metabolism. Sepsis leads to sepsis-induced dysfunction and mitochondrial damage, which is suggested as a major cause of cell metabolism disorders in these patients. The changes affect the metabolism of all macronutrients. The metabolism of all macronutrients is altered. A characteristic change in carbohydrate metabolism is the intensification of glycolysis, which in combination with the failure of entering pyruvate to the tricarboxylic acid cycle increases the formation of lactate. Sepsis also affects lipid metabolism—lipolysis in adipose tissue is upregulated, which leads to an increase in the level of fatty acids and triglycerides in the blood. At the same time, their use is disturbed, which may result in the accumulation of lipids and their toxic metabolites. Changes in the metabolism of ketone bodies and amino acids have also been described. Metabolic disorders in sepsis are an important area of research, both for their potential role as a target for future therapies (metabolic resuscitation) and for optimizing the current treatment, such as clinical nutrition.

Dexmedetomidine ameliorates endotoxin-induced acute lung injury in vivo and in vitro by preserving mitochondrial dynamic equilibrium through the HIF-1a/HO-1 signaling pathway

Increasing lines of evidence identified that dexmedetomidine (DEX) exerted protective effects against sepsis-stimulated acute lung injury via anti-inflammation, anti-oxidation and anti-apoptosis. However, the mechanisms remain unclear. Herein, we investigated whether DEX afforded lung protection by regulating the process of mitochondrial dynamics through the HIF-1a/HO-1 pathway in vivo and in vitro. Using C57BL/6J mice exposed to lipopolysaccharide, it was initially observed that preemptive administration of DEX (50μg/kg) alleviated lung pathologic injury, reduced oxidative stress indices (OSI), improved mitochondrial dysfunction, upregulated the expression of HIF-1α and HO-1, accompanied by shifting the dynamic course of mitochondria into fusion. Moreover, HO-1-knockout mice or HO-1 siRNA transfected NR8383 cells were pretreated with HIF-1α stabilizer DMOG and DEX to validate the effect of HIF-1a/HO-1 pathway on DEX-mediated mitochondrial dynamics in a model of endotoxin-induced lung injury. We found that pretreatment with DEX and DMOG distinctly relieved lung injury, decreased the levels of mitochondrial ROS and mtDNA, reduced OSI, increased nuclear accumulation of HIF-1a and HO-1 protein in wild type mice but not HO-1 KO mice. Similar observations were recapitulated in NC siRNA transfected NR8383 cells after LPS stimulation but not HO-1 siRNA transfected cells. Concertedly, DEX reversed the impaired mitochondrial morphology in LPS stimulated-wild type mice or NC siRNA transfected NR8383 cells, upregulated the expression of mitochondrial fusion protein, while downregulated the expression of fission protein in HIF-1a/HO-1 dependent pathway. Altogether, our data both in vivo and in vitro certified that DEX treatment ameliorated endotoxin-induced acute lung injury by preserving the dynamic equilibrium of mitochondrial fusion/fission through the regulation of HIF-1a/HO-1 signaling pathway.

Sepsis is associated with mitochondrial DNA damage and a reduced mitochondrial mass in the kidney of patients with sepsis-AKI

Background

Sepsis is a life-threatening condition accompanied by organ dysfunction subsequent to a dysregulated host response to infection. Up to 60% of patients with sepsis develop acute kidney injury (AKI), which is associated with a poor clinical outcome. The pathophysiology of sepsis-associated AKI (sepsis-AKI) remains incompletely understood, but mitochondria have emerged as key players in the pathogenesis. Therefore, our aim was to identify mitochondrial damage in patients with sepsis-AKI.

Methods

We conducted a clinical laboratory study using “warm” postmortem biopsies from sepsis-associated AKI patients from a university teaching hospital. Biopsies were taken from adult patients (n = 14) who died of sepsis with AKI at the intensive care unit (ICU) and control patients (n = 12) undergoing tumor nephrectomy. To define the mechanisms of the mitochondrial contribution to the pathogenesis of sepsis-AKI, we explored mRNA and DNA expression of mitochondrial quality mechanism pathways, DNA oxidation and mitochondrial DNA (mtDNA) integrity in renal biopsies from sepsis-AKI patients and control subjects. Next, we induced human umbilical vein endothelial cells (HUVECs) with lipopolysaccharide (LPS) for 48 h to mimic sepsis and validate our results in vitro.

Results

Compared to control subjects, sepsis-AKI patients had upregulated mRNA expression of oxidative damage markers, excess mitochondrial DNA damage and lower mitochondrial mass. Sepsis-AKI patients had lower mRNA expression of mitochondrial quality markers TFAM, PINK1 and PARKIN, but not of MFN2 and DRP1. Oxidative DNA damage was present in the cytosol of tubular epithelial cells in the kidney of sepsis-AKI patients, whereas it was almost absent in biopsies from control subjects. Oxidative DNA damage co-localized with both the nuclei and mitochondria. Accordingly, HUVECs induced with LPS for 48 h showed an increased mnSOD expression, a decreased TFAM expression and higher mtDNA damage levels.

Conclusion

Sepsis-AKI induces mitochondrial DNA damage in the human kidney, without upregulation of mitochondrial quality control mechanisms, which likely resulted in a reduction in mitochondrial mass.

Serum proteome-wide identified ATP citrate lyase as a novel informative diagnostic and prognostic biomarker in pediatric sepsis: A pilot study

Introduction

ATP citrate lyase (ACLY) is involved in lipid metabolism and inflammatory response in immune cells. However, the serum level of ACLY and its clinical relevance in sepsis is totally unknown.

Methods

We conducted a prospective pilot study in patients with sepsis admitted to pediatric intensive care unit (PICU) from January 2018 to December 2018.

Results

Higher levels of ACLY were detected in sera of pediatric patients with sepsis than that of healthy children. The area under the receiver operating characteristic curve (AUC) of ACLY for diagnosis of sepsis was 0.855 (95% confidence interval [CI]: 0757–0.952), and an AUC of ACLY for predicting PICU mortality was 0.770 (95% CI: 0.626–0.915). ACLY levels ≤21 ng/ml on PICU admission predicted an unfavorable prognosis among patients with sepsis with a sensitivity of 87.5% and a specificity of 67.6%. Moreover, serum ACLY levels were correlated to platelet count, IL‐18 levels, and monocyte counts in pediatric patients with sepsis, implying the potential roles of ACLY in immunometabolic regulation in sepsis.

Conclusions

ACLY is firstly identified in sera of patients with sepsis. Serum ACLY level is an additional diagnostic and prognostic biomarker in pediatric patients with sepsis.

Apolipoprotein A-V Is a Novel Diagnostic and Prognostic Predictor in Pediatric Patients with Sepsis: A Prospective Pilot Study in PICU

Background

Sepsis induces the release of lipid mediators, which control both lipid metabolism and inflammation. However, the role of serum apolipoprotein A-V (ApoA5) in sepsis is poorly understood in pediatric patients.

Methods

ApoA5 was screened from serum proteomics profile in lipopolysaccharide- (LPS-) treated mice for 2 h, 24 h, and controls. Then, we conducted a prospective pilot study, and patients with sepsis admitted to a pediatric intensive care unit (PICU) were enrolled from January 2018 to December 2018. Serum ApoA5 levels on PICU admission were determined using enzyme-linked immunosorbent assays (ELISA). Blood samples from 30 healthy children were used as control. The correlation of ApoA5 with the clinical and laboratory parameters was analyzed. Logistic regression analyses and receiver operating characteristic curve (ROC) analysis were used to investigate the potential role of serum ApoA5 as a prognostic predictor for PICU mortality in pediatric patients with sepsis.

Results

A total of 101 patients with sepsis were enrolled in this study. The PICU mortality rate was 10.9% (11/101). Serum ApoA5 levels on PICU admission were significantly lower in nonsurvivors with sepsis compared with survivors (P = 0.009). In subgroup analysis, serum levels of ApoA5 were significantly correlated with sepsis-associated multiple organ dysfunction syndrome (MODS) (P < 0.001), shock (P = 0.002), acute kidney injury (AKI) (P < 0.001), acute liver injury (ALI) (P = 0.002), and gastrointestinal (GI) dysfunction (P = 0.012), but not respiratory failure, brain injury, and pathogenic species (all P > 0.05). Correlation analyses revealed significant correlations of serum ApoA5 with Ca²⁺ concentration. Remarkably, the area under ROC curve (AUC) for serum ApoA5 levels on PICU admission was 0.789 for prediction of PICU mortality with a sensitivity of 75% and a specificity of 84.5% at a threshold value of 822 ng/mL.

Conclusions

Serum ApoA5 level is associated with sepsis-associated shock, AKI, ALI, GI dysfunction, or MODS in children. Moreover, the findings of the present study suggest a prognostic value of ApoA5 in children with sepsis, and lower serum ApoA5 than 822 ng/mL predicts worse outcome in pediatric sepsis.

Toxoplasma gondii GRA8-derived peptide immunotherapy improves tumor targeting of colorectal cancer

Targeted tumor and efficient, specific biological drug delivery in vivo has been one of the main challenges in protein-based cancer-targeted therapies. Mitochondria are potential therapeutic targets for various anti-cancer drugs. We have previously reported that protein kinase Cα-mediated phosphorylation of Toxoplasma gondii GRA8 is required for mitochondrial trafficking and regulating the interaction of the C-terminal of GRA8 with ATP5A1/SIRT3 in mitochondria. Furthermore, SIRT3 facilitates ATP5A1 deacetylation, mitochondrial activation, and subsequent antiseptic activity in vivo. Herein we developed a recombinant acidity-triggered rational membrane (ATRAM)-conjugated multifunctional GRA8 peptide (rATRAM-G8-M/AS) comprising ATRAM as the cancer-targeting cell-penetrating peptide, and essential/minimal residues for mitochondrial targeting or ATP5A1/SIRT3 binding. This peptide construct showed considerably improved potency about cancer cell death via mitochondria activity and biogenesis compared with rGRA8 alone in HCT116 human carcinoma cells, reaching an IC₅₀ value of up to 200-fold lower in vitro and 500-fold lower in vivo. Notably, rATRAM-G8-M/AS treatment showed significant therapeutic effects in a mouse xenograft model through mitochondrial metabolic resuscitation, and it produced negligible immunogenicity and immune responses in vivo. Thus, these results demonstrate that rATRAM-G8-M/AS represents a useful therapeutic strategy against tumors, particularly colon cancer. This strategy represents an urgently needed paradigm shift for therapeutic intervention.

Gasotransmitters in health and disease: a mitochondria-centered view

Gasotransmitters fulfill important roles in cellular homeostasis having been linked to various pathologies, including inflammation and cardiovascular diseases. In addition to the known pathways mediating the actions of gasotransmitters, their effects in regulating mitochondrial function are emerging. Given that mitochondria are key organelles in energy production, formation of reactive oxygen species and apoptosis, they are important mediators in preserving health and disease. Preserving or restoring mitochondrial function by gasotransmitters may be beneficial, and mitigate pathogenetic processes. In this review we discuss the actions of gasotransmitters with focus on their role in mitochondrial function and their therapeutic potential.