Characterization of Cardiac Dysfunction in Sepsis: An Ongoing Challenge

Exosomal non-coding RNAs: key regulators of inflammation-related cardiovascular disorders

Inflammation is a complex, tightly regulated process involving biochemical and cellular reactions to harmful stimuli. Often termed "the internal fire", it is crucial for protecting the body and facilitating tissue healing. While inflammation is essential for survival, chronic inflammation can be detrimental, leading to tissue damage and reduced survival. The innate immune system triggers inflammation, closely linked to the development of heart diseases, with significant consequences for individuals. Inflammation in arterial walls or the body substantially contributes to atherosclerotic disease progression, affecting the cardiovascular system. Altered lipoproteins increase the risk of excessive blood clotting, a hallmark of atherosclerotic cardiovascular disease and its complications. Integrating inflammatory biomarkers with established risk assessment techniques can enhance our ability to identify at-risk individuals, assess their risk severity, and recommend appropriate CVD prevention strategies. Exosomes, a type of extracellular vesicle, are released by various cells and mediate cell communication locally and systemically. In the past decade, exosomes have been increasingly studied for their vital roles in health maintenance and disease processes. They can transport substances like non-coding RNAs, lipids, and proteins between cells, influencing immune responses and inflammation to elicit harmful or healing effects. This study focuses on the critical role of inflammation in heart disease progression and how non-coding RNAs in exosomes modulate the inflammatory process, either exacerbating or alleviating inflammation-related damage in the cardiovascular system.

Integrating Transcriptomic and Proteomic Data: IL-27B as a Key Protein in the Development of Septic Cardiomyopathy-A Retrospective Study

BACKGROUND

Septic cardiomyopathy (SCM) is a potentially fatal complication of sepsis. In this study, transcriptomic and proteomic analyzes of serum samples from sepsis patients were conducted to uncover the underlying pathological mechanisms and identify potential therapeutic targets for SCM.

METHODS

This retrospective, dual-center study investigated the progression of sepsis to SCM in patients admitted to intensive care units. A total of 50 patients were enrolled and divided into two groups: sepsis with cardiomyopathy (25 cases) and sepsis without cardiomyopathy (25 cases). Co-expression network analysis was employed to elucidate the biological significance of differentially expressed proteins. By integrating proteomic and transcriptomic data, molecular networks were constructed to visualize interactions among key molecules, aiming to enhance data interpretation and support the study's findings.

RESULTS

Proteomic analysis identified 216 differentially expressed proteins (Fold change > 1.5, p-value < 0.05) between the two groups. Transcriptomic analysis revealed two proteins, including Interleukin-27 subunit beta (IL-27B) and carbonic anhydrase, co-downregulated in patients with septic cardiomyopathy. IL-27B was associated with the immune response, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis indicated its involvement in the cytokine-cytokine receptor interaction signaling pathway.

CONCLUSION

Comprehensive integrated transcriptomic and proteomic analyzes identified significant changes in protein expression associated with SCM, primarily associated with inflammation-related pathways and amino acid metabolism. These findings provide new insights into the pathological mechanisms of SCM and highlight potential therapeutic targets for its treatment.

TRIAL REGISTRATION

The Clinical Research Ethics Committee of Taizhou Hospital of Zhejiang Province affiliated to Wenzhou Medical University approved this study, and written informed consent was given by all patients or their legal representatives. (NO.K20201110).

Characterisation of Post-Sepsis Cardiomyopathy Using Cardiovascular Magnetic Resonance

Background: Post-sepsis cardiomyopathy is associated with an increased risk of adverse cardiovascular outcomes. It remains poorly understood, which limits therapeutic development. This study characterised post-sepsis cardiomyopathy using cardiovascular magnetic resonance (CMR) imaging. Methods: Patients admitted with acute sepsis and suspected cardiac injury or heart failure who subsequently (47 days [IQR: 22-122]) underwent CMR at a UK tertiary cardiac centre were included. Age- and gender-matched controls (n = 16) were also included. Subjects underwent CMR at 1.5 Tesla with cines, native T1- and T2-mapping, and late gadolinium enhancement (LGE) imaging. Results: Of the 22 post-sepsis patients (age 50 ± 13 years; 64% males), 13 patients (59%) had left ventricular (LV) dilatation. Patients had significantly elevated left ventricular (LV) end-diastolic and end-systolic volume indices compared to controls (p = 0.011 and p = 0.013, respectively). Eleven patients (50%) had LV systolic dysfunction (ejection fraction < 50%), most of whom (8/11) had non-ischaemic patterns of LGE (n = 7 mid-wall; n = 1 mid-wall/patchy). In the eleven patients with preserved LV systolic function (ejection fraction ≥ 50%), three patients (27%) had significant LGE (n = 1 mid-wall; n = 1 subepicardial/mid-wall; n = 1 patchy). Compared to controls, patients had elevated septal native myocardial T1 values (p < 0.001) but similar septal native myocardial T2 values (p = 0.090), suggesting the presence of myocardial fibrosis without significant oedema. Conclusions: Post-sepsis cardiomyopathy is characterised by LV dilatation, systolic dysfunction, and myocardial fibrosis in a non-ischaemic distribution. Significant myocardial oedema is not prominent several weeks post-recovery. Further work is needed to test these findings on a multi-centre basis and to develop novel therapies for post-sepsis cardiomyopathy.

Interaction between post-tumor inflammation and vascular smooth muscle cell dysfunction in sepsis-induced cardiomyopathy

Background

Sepsis-induced cardiomyopathy (SIC) presents a critical complication in cancer patients, contributing notably to heart failure and elevated mortality rates. While its clinical relevance is well-documented, the intricate molecular mechanisms that link sepsis, tumor-driven inflammation, and cardiac dysfunction remain inadequately explored. This study aims to elucidate the interaction between post-tumor inflammation, intratumor heterogeneity, and the dysfunction of VSMC in SIC, as well as to evaluate the therapeutic potential of exercise training and specific pharmacological interventions.

Methods

Transcriptomic data from NCBI and GEO databases were analyzed to identify differentially expressed genes (DEGs) associated with SIC. Weighted gene co-expression network analysis (WGCNA), gene ontology (GO), and KEGG pathway enrichment analyses were utilized to elucidate the biological significance of these genes. Molecular docking and dynamics simulations were used to investigate drug-target interactions, and immune infiltration and gene mutation analyses were carried out by means of platforms like TIMER 2.0 and DepMap to comprehend the influence of DVL1 on immune responsiveness.

Results

Through the utilization of the datasets, we discovered the core gene DVL1 that exhibited remarkable up-regulated expression both in SIC and in diverse kinds of cancers, which were associated with poor prognosis and inflammatory responses. Molecular docking revealed that Digoxin could bind to DVL1 and reduce oxidative stress in SIC. The DVL1 gene module related to SIC was identified by means of WGCNA, and the immune infiltration analysis demonstrated the distinctive immune cell patterns associated with DVL1 expression and the impact of DVL1 on immunotherapeutic resistance.

Conclusions

DVL1 is a core regulator of SIC and other cancers and, therefore, can serve as a therapeutic target. The present study suggests that targeted pharmacological therapies to enhance response to exercise regimens may be a novel therapeutic tool to reduce the inflammatory response during sepsis, particularly in cancer patients. The identified drugs, Digoxin, require further in vivo and clinical studies to confirm their effects on SIC and their potential efforts to improve outcomes in immunotherapy-resistant cancer patients.

Fermented Houttuynia cordata Juice Exerts Cardioprotective Effects by Alleviating Cardiac Inflammation and Apoptosis in Rats with Lipopolysaccharide-Induced Sepsis

BACKGROUND/OBJECTIVES

Sepsis-induced cardiac dysfunction is a major problem that often leads to severe complications and a poor prognosis. Despite the growing awareness of its impact, effective treatment options for sepsis-induced cardiac dysfunction remain limited. To date, fermented products of Houttuynia cordata (HC), known for its rich bioactive properties, have shown potential in modulating inflammatory and oxidative stress pathways. However, treatment with fermented HC juice (FHJ) in lipopolysaccharide (LPS)-induced sepsis in rats has not been investigated.

METHODS

Rats were pretreated with FHJ at doses of 200 mg/kg and 400 mg/kg for 2 weeks. After that, the rats were injected with a single dose of LPS (10 mg/kg), and 12 h after injection, they developed sepsis-induced cardiac dysfunction. Then, cardiac function, oxidative stress, inflammation, apoptosis, and cardiac injury markers were determined.

RESULTS

Pretreatment with FHJ at doses of 200 mg/kg and 400 mg/kg prevented LPS-induced cardiac dysfunction in rats by attenuating cardiac inflammation (IL-1β, TLR-4, and NF-κB levels), oxidative stress (MDA levels), and apoptosis (cleaved-caspase 3 and Bax/Bcl-2 expression) and reducing markers of cardiac injury (LDH and CK-MB levels).

CONCLUSIONS

These results suggest that FHJ could be a potential therapeutic agent for sepsis-induced heart disease.

Dexmedetomidine therapy promotes cardiac dysfunction and increases mortality in sepsis: A translational study

Previous studies demonstrated that dexmedetomidine (Dex) posttreatment aggravated myocardial dysfunction and reduced survival in septic mice. Yet, whether Dex elicits similar effects in septic patients as defined by Sepsis-3 remains unknown. This study sought to assess the effects of Dex-based sedation on mortality and cardiac dysfunction in septic patients defined by Sepsis-3 and to further reveal the mechanisms in septic rats. In the retrospective cohort study, patients were categorised into sepsis with Dex, other sedatives (propofol or midazolam) or without sedatives, mortality at 28 days were compared, and patients with measurements of cardiovascular biomarkers and echocardiography were used to examine the effect of Dex on cardiac dysfunction. Septic rats and Langendorff-perfused isolated rat hearts were used, cardiac function, mortality and pro-inflammatory mediators were analyzed. The all-cause mortality of septic patients receiving Dex reached to 35.2 % on Day 28, significantly higher than that of patients with other sedatives (16.1 %), while no difference with group of no sedatives (27.3 %). Patients in Dex group showed lower left ventricular EF and lateral mitral annular early diastolic peak velocities, but higher interventricular septum diastolic dimension compared to those with other sedatives. The plasma levels of H-FABP, NT-proBNP and HMGB1 in Dex and other sedative groups showed no difference, while both were significantly lower than the group of no sedative. Notably, Dex posttreatment deteriorated cardiac dysfunction, increasing mortality in septic rats with enhanced systemic and myocardial proinflammatory mediators, including TNF-α, IL-1β, IL-6 and VCAM-1. Mechanistical study by Langendorff-perfusion revealed that Dex directly acted on the heart, aggravating LPS-induced myocardial inflammation and dysfunction. These results suggest that Dex increases mortality and deteriorates myocardial dysfunction compared with other sedatives in septic patients defined by Sepsis 3.0, maybe partly through promoting proinflammatory response via directly acting on the heart.

Nicorandil Regulates Ferroptosis and Mitigates Septic Cardiomyopathy via TLR4/SLC7A11 Signaling Pathway

This study mainly explored the role of nicorandil in regulating ferroptosis and alleviating septic cardiomyopathy through toll-like receptor (TLR) 4/solute carrier family 7 member 11 (SLC7A11) signaling pathway. Twenty-four male SD rats were randomly divided into control, Nic (nicorandil), LPS (lipopolysaccharide), and LPS + Nic groups and given echocardiography. A detection kit was applied to measure the levels of lactic dehydrogenase (LDH), cardiac troponin I (cTnI), and creatine kinase-MB (CK-MB); HE staining and the levels of glutathione (GSH), malondialdehyde (MDA), total iron, and Fe2+ of myocardial tissues were detected. Moreover, the expression of TLR4 and SLC7A11 were measured by qRT-PCR and the proteins regulating ferroptosis (TLR4, SLC7A11, GPX4, ACSL4, DMT1, Fpn, and TfR1) were checked by western blot. Myocardial cells (H9C2) were induced with lipopolysaccharide (LPS) and transfected with si-TLR4 or SLC7A11-OE. Then, the viability, ferroptosis, and TLR4/SLC7A11 signaling pathway of cells were examined. Nicorandil could significantly increase left ventricular (LV) ejection fraction (LVEF) while reduce LV end-diastolic volume (LVEDV) and LV end-systolic volume (LVESV). Also, it greatly reduced the levels of LDH, cTnI, and CK-MB; alleviated the pathological changes of myocardial injury; notably decreased MDA, total iron, and Fe2+ levels in myocardial tissues; and significantly increased GSH level. Besides, nicorandil obviously raised protein levels of GPX4, Fpn, and SLC7A11, and decreased protein levels of ACSL4, DMT1, TfR1, and TLR4. After knockdown of TLR4 or overexpression of SLC7A11, the inhibition effect of nicorandil on ferroptosis was strengthened in LPS-induced H9C2 cells. Therefore, nicorandil may regulate ferroptosis through TLR4/SLC7A11 signaling, thereby alleviating septic cardiomyopathy.

Pathophysiological mechanisms underlying increased circulating cardiac troponin in noncardiac surgery: a narrative review

Assay-specific increases in circulating cardiac troponin are observed in 20-40% of patients after noncardiac surgery, depending on patient age, type of surgery, and comorbidities. Increased cardiac troponin is consistently associated with excess morbidity and mortality after noncardiac surgery. Despite these findings, the underlying mechanisms are unclear. The majority of interventional trials have been designed on the premise that ischaemic cardiac disease drives elevated perioperative cardiac troponin concentrations. We consider data showing that elevated circulating cardiac troponin after surgery could be a nonspecific marker of cardiomyocyte stress. Elevated concentrations of circulating cardiac troponin could reflect coordinated pathological processes underpinning organ injury that are not necessarily caused by ischaemia. Laboratory studies suggest that matching of coronary artery autoregulation and myocardial perfusion-contraction coupling limit the impact of systemic haemodynamic changes in the myocardium, and that type 2 ischaemia might not be the likeliest explanation for cardiac troponin elevation in noncardiac surgery. The perioperative period triggers multiple pathological mechanisms that might cause cardiac troponin to cross the sarcolemma. A two-hit model involving two or more triggers including systemic inflammation, haemodynamic strain, adrenergic stress, and autonomic dysfunction might exacerbate or initiate acute myocardial injury directly in the absence of cell death. Consideration of these diverse mechanisms is pivotal for the design and interpretation of interventional perioperative trials.

Factors influencing DVT formation in sepsis

INTRODUCTION

Sepsis is a global public health burden. Deep vein thrombosis (DVT) is the third most common cause of death from cardiovascular disease after heart attacks and strokes. We designed this experiment to investigate the factors influencing DVT formation in patients with sepsis.

METHODS

In this survey, 918 septic patients admitted to Peking Union Medical College Hospital, who underwent DVT screening were enrolled. The data were collected from June 8, 2013 to October 12, 2022. The differences between septic patients with and without DVT were studied from following aspects: basic information, comorbidities, inflammatory cytokines, albumin, source of infection, sequential organ failure assessment (SOFA) score, coagulation and prognosis.

MAIN RESULTS

In this study, the prevalence of DVT in patients with sepsis was 0.23. Elderly patients with sepsis were prone to DVT (p value < 0.001). In terms of comorbidities, septic patients with hypertension and atrial fibrillation were prone to DVT (p value 0.045 and 0.048). Inflammatory cytokines, such as procalcitonin (PCT), C-reactive protein (CRP), interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor (TNF)-α, had no significant correlation with DVT in patients with sepsis (p value 0.364, 0.882, 0.912, 0.789, 0.245, and 0.780). Levels of serum albumin correlated with DVT in patients with sepsis (p value 0.003). The SOFA total score had no relationship with DVT formation (p value 0.254). Coagulation and respiration function were negatively correlated with DVT (p value 0.018). Liver function was positively correlated with DVT (p value 0.020). Patients in the DVT group had longer duration of mechanical ventilation and longer intensive care unit (ICU) stays (p value < 0.001 and 0.006). There was no significant difference in survival in septic patients with and without DVT (p value 0.868).

CONCLUSIONS

The SOFA total score had no relationship with DVT formation. The function of each organ had different effects on DVT formation. Better coagulation and respiration function, easier DVT formation. Poorer liver function, easier DVT formation. DVT was associated with longer duration of mechanical ventilation and longer ICU stays.

Docosahexaenoic acid alleviates LPS-induced cytotoxicity in HL-1 cardiac cells via improving stress-induced mitochondrial fragmentation

Sepsis-induced cardiac injury is associated with oxidative stress and mitochondrial dysfunction. Docosahexaenoic acid (DHA), an essential omega-3 fatty acid, protects the injured myocardium by modulating mitochondrial dysfunction. We aimed to confirm whether the cardioprotective effect of DHA is mediated via the alleviation of mitochondrial fragmentation in lipopolysaccharide (LPS)-induced cardiomyopathy in vitro. We found that DHA improved cell viability and alleviated cardiac cell apoptosis by reducing lactate dehydrogenase (LDH) release, expression levels of Cleaved caspase-3, and Caspase 3 activity. DHA attenuated oxidative stress as evidenced by decreased ROS production and increased superoxide dismutase activity. In addition, DHA ameliorated mitochondrial dysfunction by modulating mitochondrial respiratory chain injury and mitochondrial fragmentation, especially decreasing the mitochondrial fission-related protein p-Drp1(ser 616) but no effects on Drp1, p-Drp1(ser 637), and mitochondrial fusion-related protein. Our data suggest that DHA conferred cardioprotection by alleviating oxidative stress-induced apoptosis, which may be associated with alleviation of stress-induced mitochondrial fragmentation.

Xinyang tablet ameliorates sepsis-induced myocardial dysfunction by regulating Beclin-1 to mediate macrophage autophagy and M2 polarization through LncSICRNT1 targeting E3 ubiquitin ligase TRAF6

OBJECTIVE

Xinyang Tablet (XYT) has emerged as a potential intervention to counter sepsis-induced myocardial dysfunction (SMID) by influencing macrophage autophagy and M2 polarization. This study aimed to unravel the underlying mechanism of XYT in sepsis-induced myocardial dysfunction (SIMD).

METHODS

A microarray analysis was employed to explore sepsis-related changes, and bioinformatics analysis was used to predict lncRNAs binding to tumor necrosis factor receptor-associated factor 6 (TRAF6). This studio utilized SIMD mouse models induced by lipopolysaccharide (LPS) injection, followed by treatments involving varied doses of XYT, digoxin (positive control), or si-LncSICRNT1. After seven days, evaluations encompassing mouse hair/mental state/diet/weight were measured, and cardiac function via echocardiography were conducted. Myocardial tissue changes were observed using hematoxylin-eosin staining. Additionally, bone marrow-derived macrophages (BMDMs) subjected to LPS for M1 polarization were treated with oe-LncSICRNT1, si-TRAF6 and their negative control, XYT, or autophagy inhibitor 3-Methyladenine (3-MA) (positive control). RT-qPCR and Western blot analyses were employed to assess LncSICRNT1, TRAF6, Beclin-1, LC3II/LC3I, and p62 levels. Immunohistochemistry and flow cytometry were used for M1/M2 polarization markers, while enzyme-linked immunosorbent assay (ELISA) gauged inflammatory factor levels. Interaction between TRAF6 and LncSICRNT1 was probed using RNA pull-down and RNA immunoprecipitation (RIP) assays.

RESULTS

Chip analysis obtained 1463 differentially expressed lncRNAs, including LINC01550 (LncSICRNT1). Further prediction indicated that LncSICRNT1 was highly likely to directly bind to TRAF6. XYT treatment in LPS-induced SIMD mice led to notable enhancements in sleep/hair/diet/activity, increased weight/left ventricular end-diastolic diameter (LVEDd)/LV ejection fraction (LVEF)/LV fraction shortening (LVFS). These improvements were associated with elevated LncSICRNT1 expression and decreased TRAF6 protein levels, culminating in reduced myocardial inflammatory responses and improved cardiac function. Notably, XYT was found to suppress macrophage M1 polarization, while enhancing M2 polarization, ultimately benefitting cardiac function via LncSICRNT1 modulation. Furthermore, the study revealed LncSICRNT1 modulated Beclin-1 ubiquitination and restrained macrophage autophagy by targeting TRAF6 expression.

CONCLUSION

The study highlights XYT's potential to ameliorate LPS-induced SIMD by elevating LncSICRNT1 expression, influencing TRAF6 expression, and regulating Beclin-1 ubiquitination. These actions collectively inhibit macrophage autophagy and foster M1/M2 polarization, contributing to cardiac function improvement.

Impact of cardiac troponin release and fluid resuscitation on outcomes of patients with sepsis

BACKGROUND

Septic patients are predisposed to myocardial injury manifested as cardiac troponin release (TnR). Prognostic significance and management implications of TnR and its relationship to fluid resuscitation and outcomes in the intensive care unit (ICU) setting has not been fully elucidated.

METHODS

A total of 24,778 patients with sepsis from eICU-CRD, MIMIC-III and MIMIC-IV databases were included in this retrospective study. In-hospital mortality and one-year survival were examined using multivariable regression analysis and Kaplan-Meier survival analysis with overlap weighting adjustment, as well as generalized additive models for fluid resuscitation.

RESULTS

TnR on admission was associated with higher in-hospital mortality [adjusted odds ratios (OR) = 1.33; 95% confidence interval (CI) = 1.23-1.43; p < 0.001 in unweighted analysis and adjusted OR = 1.39; 95% CI = 1.29-1.50; P < 0.001 with overlap weighting]. One-year mortality was higher in patients with admission TnR (P = 0.002). A trend was noted for association between admission TnR and 1-year mortality [adjusted OR = 1.16; 95% CI = 0.99-1.37; P = 0.067 in unweighted analysis] while the association was statistically significant after overlap weighting (adjusted OR = 1.25; 95% CI = 1.06-1.47; P = 0.008). Patients with admission TnR were less likely to benefit from more liberal fluid resuscitation. Adequate fluid resuscitation (80 ml/kg in the first 24 h of ICU stay) was associated with lower in-hospital mortality in septic patients without TnR but not in those with admission TnR.

CONCLUSIONS

Admission TnR is significantly associated with higher in-hospital mortality and 1-year mortality among septic patients. Adequate fluid resuscitation improves in-hospital mortality in septic patients without but not with admission TnR.

A comprehensive insight into the molecular and cellular mechanisms of action of resveratrol on complications of sepsis a systematic review

Sepsis and septic shock are still one of the most important medical challenges. Sepsis is an extreme and uncontrolled response of the innate immune system to invading pathogenesis. Resveratrol (3,5,4'-trihydroxytrans-stilbene), is a phenolic and non-flavonoid compound naturally produced by some plants and fruits. The object of the current study is to systematically review the impacts of resveratrol and its mechanisms of function in the management of sepsis and its related complications. The guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statements were applied to perform the study (PROSPERO: CRD42021289357). We searched Embase, Web of Science, Google Scholar, Science Direct, PubMed, ProQuest, and Scopus databases up to January 2023 by using the relevant keywords. Study criteria were met by 72 out of 1415 articles screened. The results of this systematic review depict that resveratrol can reduces the complications of sepsis by affecting inflammatory pathways, oxidative stress, and modulating immune responses. Future human randomized clinical trials are necessary due to the promising therapeutic effects of resveratrol on sepsis complications and the lack of clinical trials in this regard.

Inflammatory microRNAs in cardiovascular pathology: another brick in the wall

The regulatory role of microRNAs (miRNAs) is mainly mediated by their effect on protein expression and is recognized in a multitude of pathophysiological processes. In recent decades, accumulating evidence has interest in these factors as modulatory elements of cardiovascular pathophysiology. Furthermore, additional biological processes have been identified as new components of cardiovascular disease etiology. In particular, inflammation is now considered an important cardiovascular risk factor. Thus, in the present review, we will focus on the role of a subset of miRNAs called inflamma-miRs that may regulate inflammatory status in the development of cardiovascular pathology. According to published data, the most representative candidates that play functional roles in thromboinflammation are miR-21, miR-33, miR-34a, miR-146a, miR-155, and miR-223. We will describe the functions of these miRNAs in several cardiovascular pathologies in depth, with specific emphasis on the molecular mechanisms related to atherogenesis. We will also discuss the latest findings on the role of miRNAs as regulators of neutrophil extracellular traps and their impact on cardiovascular diseases. Overall, the data suggest that the use of miRNAs as therapeutic tools or biomarkers may improve the diagnosis or prognosis of adverse cardiovascular events in inflammatory diseases. Thus, targeting or increasing the levels of adequate inflamma-miRs at different stages of disease could help mitigate or avoid the development of cardiovascular morbidities.

MECHANISMS OF CARDIAC DYSFUNCTION IN SEPSIS

ABSTRACT

Studies in animal models of sepsis have elucidated an intricate network of signaling pathways that lead to the dysregulation of myocardial Ca 2+ handling and subsequently to a decrease in cardiac contractile force, in a sex- and model-dependent manner. After challenge with a lethal dose of LPS, male animals show a decrease in cellular Ca 2+ transients (ΔCa i ), with intact myofilament function, whereas female animals show myofilament dysfunction, with intact ΔCa i . Male mice challenged with a low, nonlethal dose of LPS also develop myofilament desensitization, with intact ΔCa i . In the cecal ligation and puncture (CLP) model, the causative mechanisms seem similar to those in the LPS model in male mice and are unknown in female subjects. ΔCa i decrease in male mice is primarily due to redox-dependent inhibition of sarco/endoplasmic reticulum Ca 2+ ATP-ase (SERCA). Reactive oxygen species (ROS) are overproduced by dysregulated mitochondria and the enzymes NADPH/NADH oxidase, cyclooxygenase, and xanthine oxidase. In addition to inhibiting SERCA, ROS amplify cardiomyocyte cytokine production and mitochondrial dysfunction, making the process self-propagating. In contrast, female animals may exhibit a natural redox resilience. Myofilament dysfunction is due to hyperphosphorylation of troponin I, troponin T cleavage by caspase-3, and overproduction of cGMP by NO-activated soluble guanylate cyclase. Depleted, dysfunctional, or uncoupled mitochondria likely synthesize less ATP in both sexes, but the role of energy deficit is not clear. NO produced by NO synthase (NOS)-3 and mitochondrial NOSs, protein kinases and phosphatases, the processes of autophagy and sarco/endoplasmic reticulum stress, and β-adrenergic insensitivity may also play currently uncertain roles.

6-Formylindolo(3,2-b)carbazole Dampens Inflammation and Reduces Endotoxin-Induced Kidney Injury via Nrf2 Activation

Patients with sepsis are at a high risk of morbidity and mortality due to multiple organ injuries caused by pathological inflammation. Although sepsis is accompanied by multiple organ injuries, acute renal injury is a significant contributor to sepsis morbidity and mortality. Thus, dampening inflammation-induced renal injury may limit severe consequences of sepsis. As several studies have suggested that 6-formylindolo(3,2-b)carbazole (FICZ) is beneficial for treating various inflammatory diseases, we aimed to examine the potential protective effect of FICZ on the acute endotoxin-induced sepsis model of kidney injury. To test this, male C57Bl/6N mice were injected with FICZ (0.2 mg/kg) or vehicle 1 h prior to an injection of either lipopolysaccharides (LPS) (10 mg/kg), to induce sepsis, or phosphate-buffered saline for 24 h. Thereafter, gene expression of kidney injury and pro-inflammatory markers, circulating cytokines and chemokines, and kidney morphology were assessed. Our results show that FICZ reduced LPS-induced acute injury in kidneys from LPS-injected mice. Furthermore, we found that FICZ dampens both renal and systemic inflammation in our sepsis model. Mechanistically, our data indicated that FICZ significantly upregulates NAD(P)H quinone oxidoreductase 1 and heme oxygenase 1 via aryl hydrocarbon receptor (AhR) and nuclear factor erythroid 2-related factor 2 (Nrf2) in the kidneys to lessen inflammation and improve septic acute kidney injury. Overall, the data of our study show that FICZ possesses a beneficial reno-protective effect against sepsis-induced renal injury via dual activation of AhR/Nrf2.

Sepsis in the Pediatric Cardiac Intensive Care Unit: An Updated Review

Sepsis remains among the most common causes of mortality in children with congenital heart disease (CHD). Extensive literature is available regarding managing sepsis in pediatric patients without CHD. Because the cardiovascular pathophysiology of children with CHD differs entirely from their typical peers, the available diagnosis and management recommendations for sepsis cannot be implemented directly in children with CHD. This review discusses the risk factors, etiopathogenesis, available diagnostic tools, resuscitation protocols, and anesthetic management of pediatric patients suffering from various congenital cardiac lesions. Further research should focus on establishing a standard guideline for managing children with CHD with sepsis and septic shock admitted to the intensive care unit.

Electrocardiographic findings and prognostic values in patients hospitalised with COVID-19 in the World Heart Federation Global Study

BACKGROUND

COVID-19 affects the cardiovascular system and ECG abnormalities may be associated with worse prognosis. We evaluated the prognostic value of ECG abnormalities in individuals with COVID-19.

METHODS

Multicentre cohort study with adults hospitalised with COVID-19 from 40 hospitals across 23 countries. Patients were followed-up from admission until 30 days. ECG were obtained at each participating site and coded according to the Minnesota coding criteria. The primary outcome was defined as death from any cause. Secondary outcomes were admission to the intensive care unit (ICU) and major adverse cardiovascular events (MACE). Multiple logistic regression was used to evaluate the association of ECG abnormalities with the outcomes.

RESULTS

Among 5313 participants, 2451 had at least one ECG and were included in this analysis. The mean age (SD) was 58.0 (16.1) years, 60.7% were male and 61.1% from lower-income to middle-income countries. The prevalence of major ECG abnormalities was 21.3% (n=521), 447 (18.2%) patients died, 196 (8.0%) had MACE and 1115 (45.5%) were admitted to an ICU. After adjustment, the presence of any major ECG abnormality was associated with a higher risk of death (OR 1.39; 95% CI 1.09 to 1.78) and cardiovascular events (OR 1.81; 95% CI 1.30 to 2.51). Sinus tachycardia (>120 bpm) with an increased risk of death (OR 3.86; 95% CI 1.97 to 7.48), MACE (OR 2.68; 95% CI 1.10 to 5.85) and ICU admission OR 1.99; 95% CI 1.03 to 4.00). Atrial fibrillation, bundle branch block, ischaemic abnormalities and prolonged QT interval did not relate to the outcomes.

CONCLUSION

Major ECG abnormalities and a heart rate >120 bpm were prognostic markers in adults hospitalised with COVID-19.

HSP70 alleviates sepsis-induced cardiomyopathy by attenuating mitochondrial dysfunction-initiated NLRP3 inflammasome-mediated pyroptosis in cardiomyocytes

BACKGROUND

Sepsis-induced cardiomyopathy (SIC) is an identified serious complication of sepsis that is associated with adverse outcomes and high mortality. Heat shock proteins (HSPs) have been implicated in suppressing septic inflammation. The aim of this study was to investigate whether HSP70 can attenuate cellular mitochondrial dysfunction, exuberated inflammation and inflammasome-mediated pyroptosis for SIC intervention.

METHODS

Mice with cecal ligation plus perforation (CLP) and lipopolysaccharide (LPS)-treated H9C2 cardiomyocytes were used as models of SIC. The mouse survival rate, gross profile, cardiac function, pathological changes and mitochondrial function were observed by photography, echocardiography, hematoxylin-eosin staining and transmission electron microscopy. In addition, cell proliferation and the levels of cardiac troponin I (cTnI), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were determined by Cell Counting Kit-8, crystal violet staining and enzyme-linked immunosorbent assay. Moreover, mitochondrial membrane potential was assessed by immunofluorescence staining, and dynamin-related protein 1 and pyroptosis-related molecules [nucleotide-binding domain, leucine-rich-repeat containing family pyrin domain-containing 3 (NLRP3), caspase-1, gasdermin-D (GSDMD), gasdermin-D N-terminal (GSDMD-N)] were measured by western blotting, immunoprecipitation and immunoblotting. Finally, hsp70.1 knockout mice with CLP were used to verify the effects of HSP70 on SIC and the underlying mechanism.

RESULTS

Models of SIC were successfully established, as reduced consciousness and activity with liparotrichia in CLP mice were observed, and the survival rate and cardiac ejection fraction (EF) were decreased; conversely, the levels of cTnI, TNF-α and IL-1β and myocardial tissue damage were increased in CLP mice. In addition, LPS stimulation resulted in a reduction in cell viability, mitochondrial destabilization and activation of NLRP3-mediated pyroptosis molecules in vitro. HSP70 treatment improved myocardial tissue damage, survival rate and cardiac dysfunction caused by CLP. Additionally, HSP70 intervention reversed LPS-induced mitochondrial destabilization, inhibited activation of the NLRP3 inflammasome, caspase-1, GSDMD and GSDMD-N, and decreased pyroptosis. Finally, knockout of hsp70.1 mice with CLP aggravated cardiac dysfunction and upregulated NLRP3 inflammasome activity, and exogenous HSP70 significantly rescued these changes. It was further confirmed that HSP70 plays a protective role in SIC by attenuating mitochondrial dysfunction and inactivating pyroptotic molecules.

CONCLUSIONS

Our study demonstrated that mitochondrial destabilization and NLRP3 inflammasome activation-mediated pyroptosis are attributed to SIC. Interestingly, HSP70 ameliorates sepsis-induced myocardial dysfunction by improving mitochondrial dysfunction and inhibiting the activation of NLRP3 inflammasome-mediated pyroptosis, and such a result may provide approaches for novel therapies for SIC.

Septic Cardiomyopathy: From Pathophysiology to the Clinical Setting

The onset of cardiomyopathy is a common feature in sepsis, with relevant effects on its pathophysiology and clinical care. Septic cardiomyopathy is characterized by reduced left ventricular (LV) contractility eventually associated with LV dilatation with or without right ventricle failure. Unfortunately, such a wide range of ultrasonographic findings does not reflect a deep comprehension of sepsis-induced cardiomyopathy, but rather a lack of consensus about its definition. Several echocardiographic parameters intrinsically depend on loading conditions (both preload and afterload) so that it may be challenging to discriminate which is primitive and which is induced by hemodynamic perturbances. Here, we explore the state of the art in sepsis-related cardiomyopathy. We focus on the shortcomings in its definition and point out how cardiac performance dynamically changes in response to different hemodynamic clusters. A special attention is also given to update the knowledge about molecular mechanisms leading to myocardial dysfunction and that recall those of myocardial hibernation. Ultimately, the aim of this review is to highlight the unsolved issue in the field of sepsis-induced cardiomyopathy as their implementation would lead to improve risk stratification and clinical care.

Protective Effect of the Chinese Herb Draba Scabra on the Sepsis Myocarditis in Molecular Mechanism

Objective

The aim of this study was to observe the efficacy and mechanism of Draba scabra in sepsis myocarditis.

Methods

The efficacy and pathways of action of Draba scabra on septic myocarditis were evaluated by making a rat model of sepsis with appendix perforation, using Draba scabra for pharmacological intervention, and measuring serum inflammatory factors, cardiac function indexes and parameters, and P38 protein expression in each group of rats, respectively.

Results

The inflammatory factor level, apoptotic index of cardiomyocytes, and P38-MARK protein were significantly higher, while the cardiac function index and hemodynamic index were significantly decreased in group B, while the opposite was true in group E. The treatment was also found to be dose-dependent.

Conclusion

Draba scabra pretreatment effectively reduces the inflammatory response and improves hemodynamic indexes in septic rats. The mechanism may be via the P38-MARK pathway to protect the myocardium.

Non-coding RNAs in necroptosis, pyroptosis, and ferroptosis in cardiovascular diseases

Accumulating evidence has proved that non-coding RNAs (ncRNAs) play a critical role in the genetic programming and gene regulation of cardiovascular diseases (CVDs). Cardiovascular disease morbidity and mortality are rising and have become a primary public health issue that requires immediate resolution through effective intervention. Numerous studies have revealed that new types of cell death, such as pyroptosis, necroptosis, and ferroptosis, play critical cellular roles in CVD progression. It is worth noting that ncRNAs are critical novel regulators of cardiovascular risk factors and cell functions by mediating pyroptosis, necroptosis, and ferroptosis. Thus, ncRNAs can be regarded as promising therapeutic targets for treating and diagnosing cardiovascular diseases. Recently, there has been a surge of interest in the mediation of ncRNAs on three types of cell death in regulating tissue homeostasis and pathophysiological conditions in CVDs. Although our understanding of ncRNAs remains in its infancy, the studies reviewed here may provide important new insights into how ncRNAs interact with CVDs. This review summarizes what is known about the functions of ncRNAs in modulating cell death-associated CVDs and their role in CVDs, as well as their current limitations and future prospects.

m6A Methylation in Cardiovascular Diseases: From Mechanisms to Therapeutic Potential

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality worldwide. Recent studies have shown that n6-methyladenosine (m6A) plays a major role in cardiovascular homeostasis and pathophysiology. These studies have confirmed that m6A methylation affects the pathophysiology of cardiovascular diseases by regulating cellular processes such as differentiation, proliferation, inflammation, autophagy, and apoptosis. Moreover, plenty of research has confirmed that m6A modification can delay the progression of CVD via the post-transcriptional regulation of RNA. However, there are few available summaries of m6A modification regarding CVD. In this review, we highlight advances in CVD-specific research concerning m6A modification, summarize the mechanisms underlying the involvement of m6A modification during the development of CVD, and discuss the potential of m6A modification as a therapeutic target of CVD.

Aortic Stenosis Severity: Rhythm Makes a Difference

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Bradycardia may increase aortic valve flow by increasing ventricular filling.

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Elevated aortic flow may skew accurate evaluation of AS.

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Permanent AF may increase diastolic filling variability.

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Correction of abnormal flow conditions is crucial to assess AS.

Effect of Glucose-Insulin-Potassium Infusion on Hemodynamics in Patients with Septic Shock

BACKGROUND: Glucose-insulin-potassium (GIK) demonstrates a cardioprotective effect by providing metabolic support and anti-inflammatory action, and may be useful in septic myocardial depression. AIM: The aim of this study was to assess role of GIK infusion in improving hemodynamics in patients with septic shock in addition to its role in myocardial protection and preventing occurrence of sepsis-induced myocardial dysfunction and sepsis-induced arrhythmias. METHODS: This study was conducted on 75 patients admitted to the Critical Care Department in Cairo University Hospital with the diagnosis of septic shock during the period from January 2019 to December 2019. Patients were divided into two groups; first group was managed according to the last guidelines of surviving sepsis campaign and was subjected to the GIK infusion protocol while second group was managed following the last guidelines of surviving sepsis campaign only without adding GIK infusion. RESULTS: Patients in the GIK group showed better lactate clearance (50% vs. 46.7%) and less time needed for successful weaning of vasopressors than the control group (3.57±1.16 vs. 3.6±1.45 days) thought not reaching statistical significance. There was no statistically significant difference between both groups regarding development of septic-induced cardiomyopathy (16.7% in the control group vs. 13.3% in the GIK group); however, patients with hypodynamic septic shock showed better improvement in hemodynamic profile in the GIK group. Sepsis-induced arrhythmias occurred more in patients of the control group than in patients of the GIK group with no statistically significant difference between both groups (33.3% vs. 20%, p = 0.243). Few side effects were developed as a result of using GIK infusion protocol. CONCLUSIONS: GIK may help in improving hemodynamics and weaning of vasopressors in patients with refractory septic shock and those with septic induced cardiomyopathy. The use of GIK was well tolerated with minimal adverse reactions.

Effects of chronic Porphylomonas gingivalis lipopolysaccharide infusion on cardiac dysfunction in mice

OBJECTIVE

Periodontitis (PD) is a chronic inflammatory disease of tooth-supportive tissue. An association between PD and cardiovascular disease (CVD) has been established. Although PD is generally accepted as a risk factor for CVD, the existence of a relationship remains debatable. Possible mechanisms include the release of inflammatory mediators such as lipopolysaccharide (LPS), which may spread systemically and promote CVD.

METHODS

To compare the effects of lipopolysaccharide derived from Porphylomonas gingivalis (PG-LPS) on cardiac muscle in mice, mice were treated for 1 week with/without PG-LPS at a dose equivalent to the circulating level in PD patients (0.8 mg/kg/day).

RESULTS

Cardiac function in terms of left ventricular ejection function was significantly decreased at 1 week compared to that in the control (from 66 ± 0.5% to 57 ± 1.1%). Compared to the controls, the number of apoptotic myocytes and the area of fibrosis were significantly increased by approximately 2.7-fold and 14-fold, respectively. The impairment of cardiac function appeared to involve the activation of cAMP/PKA signaling and cAMP/calmodulin kinase II signaling (CaMKII), leading to cardiac fibrosis, myocyte apoptosis and heart failure.

CONCLUSIONS

Our results indicate that cAMP/PKA and cAMP/CaMKII signaling may be a new therapeutic target for the treatment of cardiovascular diseases in patients with periodontitis.

The Long-term Effect of Dobutamine on Intrinsic Myocardial Function and Myocardial Injury in Septic Rats with Myocardial Dysfunction

ABSTRACT

Dobutamine (DOB) is recommended as an inotrope for septic patients with low cardiac output, but its long-term impact on sepsis-induced cardiomyopathy remains unclear. This study investigated the long-term effect of DOB on septic myocardial dysfunction and injury. Rats were exposed to cecal ligation and puncture (CLP), the intrinsic myocardial function, other organ functions, hemodynamics, inflammatory response, serum myocardial injury biomarkers, myocardial apoptosis, and vascular permeability were determined. At 6 h after CLP, the left ventricular ±dP/dt were significantly depressed, cardiac tumor necrosis factor-α and vascular cell adhesion molecule-1 expression were increased, but not serum cardiac troponin I (cTnI), N-terminal pro-brain natriuretic peptide (NT-proBNP), heart-type fatty acid-binding protein (H-FABP), creatinine, and urea nitrogen concentrations in CLP group compared with controls. At 9 h after CLP, hepatic dysfunction was present in CLP rats compared with controls. At 6 h after CLP, DOB treatment did not affect hemodynamics, the left ventricular ±dP/dt, cytokine levels in serum and myocardium, as well as cardiomyocyte apoptosis and cardiac vascular hyperpermeability at 20 h after CLP. However, DOB (10.0 μg/kg) increased serum IL-10 level and improved survival in septic rats. These results indicate that the intrinsic myocardial depression occurs earlier than hepatic and renal dysfunction in sepsis and serum cTnI, NT-proBNP, and H-FABP are not suitable as early biomarkers for sepsis-induced myocardial dysfunction. Although DOB treatment (10.0 μg/kg) in the presence of myocardial dysfunction improves survival in septic rats, it neither improves myocardial function and hemodynamics nor attenuates myocardial injury at the later stage of sepsis.

Application of an Exploratory Knowledge-Discovery Pipeline Based on Machine Learning to Multi-Scale OMICS Data to Characterise Myocardial Injury in a Cohort of Patients with Septic Shock: An Observational Study

Currently, there is no therapy targeting septic cardiomyopathy (SC), a key contributor to organ dysfunction in sepsis. In this study, we used a machine learning (ML) pipeline to explore transcriptomic, proteomic, and metabolomic data from patients with septic shock, and prospectively collected measurements of high-sensitive cardiac troponin and echocardiography. The purposes of the study were to suggest an exploratory methodology to identify and characterise the multiOMICs profile of (i) myocardial injury in patients with septic shock, and of (ii) cardiac dysfunction in patients with myocardial injury. The study included 27 adult patients admitted for septic shock. Peripheral blood samples for OMICS analysis and measurements of high-sensitive cardiac troponin T (hscTnT) were collected at two time points during the ICU stay. A ML-based study was designed and implemented to untangle the relations among the OMICS domains and the aforesaid biomarkers. The resulting ML pipeline consisted of two main experimental phases: recursive feature selection (FS) assessing the stability of biomarkers, and classification to characterise the multiOMICS profile of the target biomarkers. The application of a ML pipeline to circulate OMICS data in patients with septic shock has the potential to predict the risk of myocardial injury and the risk of cardiac dysfunction.

Clinical impact of visually assessed right ventricular dysfunction in patients with septic shock

We retrospectively analyzed data from the Medical Information Mart for Intensive Care-III critical care database to determine whether visually-assessed right ventricular (RV) dysfunction was associated with clinical outcomes in septic shock patients. Associations between visually-assessed RV dysfunction by echocardiography and in-hospital mortality, lethal arrhythmia, and hemodynamic indicators to determine the prognostic value of RV dysfunction in patients with septic shock were analyzed. Propensity score analysis showed RV dysfunction was associated with increased risk of in-hospital death in patients with septic shock (adjusted odds ratio [OR] 2.15; 95% confidence interval [CI] 1.99–2.32; P < 0.001). In multivariate logistic regression analysis, RV dysfunction was associated with in-hospital death (OR 2.19; 95% CI 1.91–2.53; P < 0.001), lethal arrhythmia (OR 2.19; 95% CI 1.34–3.57; P < 0.001), and tendency for increased blood lactate levels (OR 1.31; 95% CI 1.14–1.50; P < 0.001) independent of left ventricular (LV) dysfunction. RV dysfunction was associated with lower cardiac output, pulmonary artery pressure index, and RV stroke work index. In patients with septic shock, visually-assessed RV dysfunction was associated with in-hospital mortality, lethal arrhythmia, and circulatory insufficiency independent of LV dysfunction. Visual assessment of RV dysfunction using echocardiography might help to identify the short-term prognosis of patients with septic shock by reflecting hemodynamic status.

Lipopolysaccharide Alters the m6A Epitranscriptomic Tagging of RNAs in Cardiac Tissue

N6-methyladenosine (m⁶A) modification plays important roles in the pathology of a variety of diseases. However, the roles of m⁶A modification in sepsis-induced myocardial dysfunction are not well defined. Rats were divided into control and lipopolysaccharide (LPS)-induced sepsis group. Global m⁶A levels of left ventricle tissue were measured by LC-MS/MS, and transcriptome-wide m⁶A modifications were profiled using epitranscriptomic microarrays (mRNAs and lncRNAs). Bioinformatics analysis was conducted to understand the functional implications of m⁶A modifications during sepsis. Methylated lncRNAs and mRNAs were measured by m⁶A single-base site qPCR. The global m⁶A levels in left ventricle tissue were significantly decreased in the LPS group. While 27 transcripts (23 mRNAs and four lncRNAs) were hypermethylated, 46 transcripts (39 mRNAs and 7 lncRNAs) were hypomethylated in the LPS group. The mRNA expression of writers and readers was significantly decreased in the LPS group. The m⁶A modification of Clec1b, Stk38l and Tnfrsf26 was associated with platelet activation and apoptotic pathways. Moreover, the decrease in m⁶A modification of lncRNA XR_346,771 may be related to cation import in cardiac tissue. Our data provide novel information regarding changes to m⁶A modifications in cardiac tissue during sepsis, and m⁶A modifications might be promising therapeutic targets.

Comparative Early Hemodynamic Profiles in Patients Presenting to the Emergency Department with Septic and Nonseptic Acute Circulatory Failure Using Focused Echocardiography

Study Objective:

We evaluated the early hemodynamic profile of patients presenting with acute circulatory failure to the Emergency Department (ED) using focused echocardiography performed by emergency physicians after a dedicated training program.

Methods:

Patients presenting to the ED with an acute circulatory failure of any origin were successively examined by a recently trained emergency physician and by an expert in critical care echocardiography. Operators independently performed and interpreted online echocardiographic examinations to determine the leading mechanism of acute circulatory failure.

Results:

Focused echocardiography could be performed in 100 of 114 screened patients (55 with sepsis/septic shock and 45 with shock of other origin) after a median fluid loading of 500 mL (interquartile range: 187–1,500 mL). A hypovolemic profile was predominantly observed whether the acute circulatory failure was of septic origin or not (33/55 [60%] vs. 23/45 [51%]: P = 0.37). Although a vasoplegic profile associated with a hyperkinetic left ventricle was most frequently identified in septic patients when compared with their counterparts (17/55 [31%] vs. 5/45 [11%]: P = 0.02), early left or right ventricular failure was observed in 31% of them. Hemodynamic profiles were adequately appraised by recently trained emergency physicians, as reflected by a good-to-excellent agreement with the expert's assessment (Κ: 0.61–0.85).

Conclusions:

Hypovolemia was predominantly identified in patients presenting to the ED with acute circulatory failure. Although vasoplegia was more frequently associated with sepsis, early ventricular dysfunction was also depicted in septic patients. Focused echocardiography seemed reliable when performed by recently trained emergency physicians without previous experience in ultrasound.

Low-power infrared laser modulates telomere length in heart tissue from an experimental model of acute lung injury

Acute lung injury and acute respiratory distress syndrome can occur as a result of sepsis. Cardiac dysfunction is a serious component of multi-organ failure caused by severe sepsis. Telomere shortening is related to several heart diseases. Telomeres are associated with the shelterin protein complex, which contributes to the maintenance of telomere length. Low-power infrared lasers modulate mRNA levels of shelterin complex genes. This study aimed to evaluate effects of a low-power infrared laser on mRNA relative levels of genes involved in telomere stabilization and telomere length in heart tissue of an experimental model of acute lung injury caused by sepsis. Animals were divided into six groups, treated with intraperitoneal saline solution, saline solution and exposed to a low-power infrared laser at 10 J cm⁻² and 20 J cm⁻², lipopolysaccharide (LPS), and LPS and, after 4 h, exposed to a low-power infrared laser at 10 J cm⁻² and 20 J cm⁻². The laser exposure was performed only once. Analysis of mRNA relative levels and telomere length by RT-qPCR was performed. Telomere shortening and reduction in mRNA relative levels of TRF1 mRNA in heart tissues of LPS-induced ALI animals were observed. In addition, laser exposure increased the telomere length at 10 J cm⁻² and modulated the TRF1 mRNA relative levels of at 20 J cm⁻² in healthy animals. Although the telomeres were shortened and mRNA levels of TRF1 gene were increased in nontreated controls, the low-power infrared laser irradiation increased the telomere length at 10 J cm⁻² in cardiac tissue of animals affected by LPS-induced acute lung injury, which suggests that telomere maintenance is a part of the photobiomodulation effect induced by infrared radiation.

SIRT1 Mediates Septic Cardiomyopathy in a Murine Model of Polymicrobial Sepsis

BACKGROUND

Cardiac dysfunction, a common complication from severe sepsis, is associated with increased morbidity and mortality. However, the molecular mechanisms of septic cardiac dysfunction are poorly understood. SIRT1, a member of the sirtuin family of NAD+-dependent protein deacetylases, is an important immunometabolic regulator of sepsis, and sustained SIRT1 elevation is associated with worse outcomes and organ dysfunction in severe sepsis. Herein, we explore the role of SIRT1 in septic cardiac dysfunction using a murine model of sepsis.

METHODS

An in vitro model of inflammation in isolated H9c2 cardiomyocytes was used to confirm SIRT1 response to stimulation with lipopolysaccharide (LPS), followed by a murine model of cecal ligation and puncture (CLP) to investigate the molecular and echocardiographic response to sepsis. A selective SIRT1 inhibitor, EX-527, was employed to test for SIRT1 participation in septic cardiac dysfunction.

RESULTS

SIRT1 mRNA and protein levels in cultured H9c2 cardiomyocytes were significantly elevated at later time points after stimulation with LPS. Similarly, cardiac tissue harvested from C57BL/6 mice 36 h after CLP demonstrated increased expression of SIRT1 mRNA and protein compared with sham controls. Administration of EX-527 18 h after CLP reduced SIRT1 protein expression in cardiac tissue at 36 h. Moreover, treatment with EX-527 improved cardiac performance with increased global longitudinal strain and longitudinal strain rate.

CONCLUSIONS

Our findings reveal that SIRT1 expression increases in isolated cardiomyocytes and cardiac tissue after sepsis inflammation. Moreover, rebalancing SIRT1 excess in late sepsis improves cardiac performance, suggesting that SIRT1 may serve as a therapeutic target for septic cardiomyopathy.

Diagnostic Value of High-Sensitivity Troponin T for Subclinical Left Ventricular Systolic Dysfunction in Patients with Sepsis

BACKGROUND

Left ventricular systolic dysfunction (LVSD) is common in sepsis. Speckle-tracking echocardiography (STE) is a useful emerging tool for evaluating the intrinsic left ventricular systolic function. High-sensitivity cardiac troponin T (hs-cTnT) is the most sensitive biomarker of myocardial injury. However, there are limited data regarding the association between hs-cTnT level and left ventricular systolic dysfunction based on STE in septic patients. We performed this prospective study to evaluate the diagnostic value of hs-cTnT level for subclinical left ventricular systolic dysfunction measured by STE in septic patients according to the sepsis-3 definition.

METHODS

Patients with sepsis based on sepsis-3 definition admitted to the intensive care unit were prospectively performed STE and hs-cTnT level within 24 hours after the onset of sepsis. Baseline clinical and echocardiographic variables were collected. Left ventricular systolic dysfunction was defined as a global longitudinal strain of ≥-15%.

RESULTS

During a 19-month period, 116 patients were enrolled in the study. The elevated hs-cTnT level was seen in 86.2% of septic patients, and 43.1% of patients had LVSD on STE. The median hs-cTnT level and the proportion of elevated hs-cTnT level (>14 ng/L) were significantly higher in patients with LVSD than in patients without LVSD. The area under the ROC curves of hs-cTnT to detect LVSD was 0.73 (P < 0.001). In the multivariate analysis, hs-cTnT (HR, 1.002; 95% CI, 1.000 to 1.004; P = 0.025) and septic shock (HR, 7.6; 95% CI, 2.25 to 25.76; P = 0.001) were independent predictors of LVSD.

CONCLUSION

Our study indicated that the serum hs-cTnT level might be a useful biomarker for detecting LVSD in septic patients.

Polydatin Alleviates Septic Myocardial Injury by Promoting SIRT6-Mediated Autophagy

Sepsis is a life-threatening condition. Polydatin (PD), a small natural compound from Polygonum cuspidatum, possesses antioxidant and anti-inflammatory properties. However, the protective mechanism of PD on sepsis-induced acute myocardial damage is still unclear. The aim of this study was to investigate the effect and mechanism of action of PD on lipopolysaccharide (LPS)-induced H9c2 cells and in a rat model of sepsis, and explored the role of PD-upregulated sirtuin (SIRT)6. LPS-induced H9c2 cells were used to simulate sepsis. Cecal ligation and puncture (CLP)-induced sepsis in rats were used to verify the protective effect of PD. ELISA, western blotting, immunofluorescence, immunohistochemistry, and flow cytometry were used to study the protective mechanism of PD against septic myocardial injury. PD pretreatment suppressed LPS-induced H9c2 cell apoptosis by promotion of SIRT6-mediated autophagy. Downregulation of SIRT6 or inhibition of autophagy reversed the protective effect of PD on LPS-induced apoptosis. PD pretreatment also suppressed LPS-induced inflammatory factor expression. CLP-induced sepsis in rats showed that PD pretreatment decreased CLP-induced myocardial apoptosis and serum tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 expression. 3-Methyladenine (autophagy inhibitor) pretreatment prevented the protective effect of PD on septic cardiomyopathy. SIRT6 expression was increased with PD treatment, which confirmed that PD attenuates septic cardiomyopathy by promotion of SIRT6-mediated autophagy. All these results indicate that PD has potential therapeutic effects that alleviate septic myocardial injury by promotion of SIRT6-mediated autophagy.

Cardiovascular Responses During Sepsis

Sepsis is the life-threatening organ dysfunction arising from a dysregulated host response to infection. Although the specific mechanisms leading to organ dysfunction are still debated, impaired tissue oxygenation appears to play a major role, and concomitant hemodynamic alterations are invariably present. The hemodynamic phenotype of affected individuals is highly variable for reasons that have been partially elucidated. Indeed, each patient's circulatory condition is shaped by the complex interplay between the medical history, the volemic status, the interval from disease onset, the pathogen, the site of infection, and the attempted resuscitation. Moreover, the same hemodynamic pattern can be generated by different combinations of various pathophysiological processes, so the presence of a given hemodynamic pattern cannot be directly related to a unique cluster of alterations. Research based on endotoxin administration to healthy volunteers and animal models compensate, to an extent, for the scarcity of clinical studies on the evolution of sepsis hemodynamics. Their results, however, cannot be directly extrapolated to the clinical setting, due to fundamental differences between the septic patient, the healthy volunteer, and the experimental model. Numerous microcirculatory derangements might exist in the septic host, even in the presence of a preserved macrocirculation. This dissociation between the macro- and the microcirculation might account for the limited success of therapeutic interventions targeting typical hemodynamic parameters, such as arterial and cardiac filling pressures, and cardiac output. Finally, physiological studies point to an early contribution of cardiac dysfunction to the septic phenotype, however, our defective diagnostic tools preclude its clinical recognition. © 2021 American Physiological Society. Compr Physiol 11:1605-1652, 2021.

Whole body periodic acceleration (pGz) improves endotoxin induced cardiomyocyte contractile dysfunction and attenuates the inflammatory response in mice

Sepsis-induces myocardial contractile dysfunction. We previously showed that whole body periodic acceleration (pGz), the sinusoidal motion of the supine body head-foot ward direction significantly improves survival and decreases microvascular permeability in a lethal model of sepsis. We tested the hypothesis that pGz improves LPS induced cardiomyocyte contractile dysfunction and decreases LPS pro-inflammatory cytokine response when applied pre- or post-treatment. Isolated cardiomyocytes were obtained from mice that received LPS who had been pre-treated with pGz for three days (pGz-LPS) or control. Peak shortening (PS), maximal velocity of shortening (+dL/dt), and relengthening (-dL/dt) as well as diastolic intracellular calcium concentration ([Ca⁺²]_d), sodium ([Na⁺]_d), reactive oxygen species (ROS), and cardiac troponin (cTnT) production were measured. LPS decreased PS, +dL/dt, and -dL/dt, by 37%, 41% and 35% change respectively (p < 0.01), increased [Ca⁺²]_d, [Na⁺]_d, ROS, and cTnT by 343%, 122%, 298%, and 610% change respectively (p < 0.01) compared to control. pGz pre-treatment attenuated the parameters mentioned above. In a separate cohort, the effects of a lethal dose of LPS on protein expression of nitric oxide synthases (iNOS, eNOS, nNOS), pro- and anti-inflammatory cytokines in hearts of mice was studied in pre-treated with pGz for three days prior to LPS (pGz-LPS) and post-treated with pGz 30 min after LPS (LPS-pGz) were determined. LPS increased expression of early and late iNOS and decreased expression of eNOS, phosphorylated eNOS (p-eNOS), and nNOS. Both pre- and post-treatment with pGz markedly reduced early and late pro-inflammatory surge. Therefore, pre- and post-treatment with pGz improves LPS-induced cardiomyocyte dysfunction, decreases iNOS expression, and increases cytoprotective eNOS and nNOS, with decreased pro-inflammatory response. Such results have potential for translation to benefit outcomes in human sepsis.

CaMKII-dependent ryanodine receptor phosphorylation mediates sepsis-induced cardiomyocyte apoptosis

Sepsis is associated with cardiac dysfunction, which is at least in part due to cardiomyocyte apoptosis. However, the underlying mechanisms are far from being understood. Using the colon ascendens stent peritonitis mouse model of sepsis (CASP), we examined the subcellular mechanisms that mediate sepsis‐induced apoptosis. Wild‐type (WT) CASP mice hearts showed an increase in apoptosis respect to WT‐Sham. CASP transgenic mice expressing a CaMKII inhibitory peptide (AC3‐I) were protected against sepsis‐induced apoptosis. Dantrolene, used to reduce ryanodine receptor (RyR) diastolic sarcoplasmic reticulum (SR) Ca²⁺ release, prevented apoptosis in WT‐CASP. To examine whether CaMKII‐dependent RyR2 phosphorylation mediates diastolic Ca²⁺ release and apoptosis in sepsis, we evaluated apoptosis in mutant mice hearts that have the CaMKII phosphorylation site of RyR2 (Serine 2814) mutated to Alanine (S2814A). S2814A CASP mice did not show increased apoptosis. Consistent with RyR2 phosphorylation‐dependent enhancement in diastolic SR Ca²⁺ release leading to mitochondrial Ca²⁺ overload, mitochondrial Ca²⁺ retention capacity was reduced in mitochondria isolated from WT‐CASP compared to Sham and this reduction was absent in mitochondria from CASP S2814A or dantrolene‐treated mice. We conclude that in sepsis, CaMKII‐dependent RyR2 phosphorylation results in diastolic Ca²⁺ release from SR which leads to mitochondrial Ca²⁺ overload and apoptosis.

Prognostic value and time course evolution left ventricular global longitudinal strain in septic shock: an exploratory prospective study

Our main objective was to describe the course of GLS during the first days of septic shock and to assess the agreement between GLS values and longitudinal strain measured in apical four chambers. A prospective observational single centre study was conducted at the Nimes University Hospital's ICU. All patients admitted for a diagnosis of septic shock without pre-existing heart disease were eligible. Echocardiography (LVEF and GLS) was performed on the first day, and repeated once between day 3 and day 5 then once between day 6 and day 8. We enrolled 40 consecutive patients. Four patients were excluded. In overall population, GLS at T1 was impaired (- 11.0%, IQR(interquartile range) [- 15; - 10]). On T2 exams, a significant improvement of the GLS (- 11% vs - 16% p = 0.02) was observed whereas LVEF remained stable over time. A good agreement between GLS and longitudinal strain measured on a four chambers view was found. Based on the Bland and Altman method, the mean of differences for T1 exams was 0.1 (95% CI [- 0.6; 0.8]) with limits of agreement ranging from - 4 to 4. Myocardial strain is depressed at the early phase of septic shock and improves over time. A single measurement of LS4C view appears sufficient at bedside.

MG53 Protects against Sepsis-Induced Myocardial Dysfunction by Upregulating Peroxisome Proliferator-Activated Receptor-α

Background

The heart is one of the most commonly affected organs during sepsis. Mitsugumin-53 (MG53) has attracted attention in research due to its cardioprotective function. However, the role of MG53 in sepsis-induced myocardial dysfunction (SIMD) remains unknown. The purpose of this study was to explore the underlying mechanism of MG53 in SIMD and investigate its potential relationship with peroxisome proliferator-activated receptor-α (PPARα).

Methods

The cecal ligation and puncture (CLP) model was created to induce SIMD in rats. Protein levels of MG53 and PPARα, cardiac function, cardiomyocyte injury, myocardial oxidative stress and inflammatory indicators, and cardiomyocyte apoptosis were measured at 18 h after CLP. The effects of MG53 on PPARα in SIMD were investigated via preconditioning recombinant human MG53 (rhMG53) and PPARα antagonist GW6471.

Results

The expression of MG53 and PPARα sharply decreased in the myocardium at 18 h after CLP. Compared with the sham group, cardiac function was significantly depressed, which was associated with the destructed myocardium, upregulated oxidative stress indicators and proinflammatory cytokines, and excessive cardiomyocyte apoptosis in the CLP group. Supplementation with rhMG53 enhanced myocardial MG53, increased the survival rate with improved cardiac function, and reduced oxidative stress, inflammation, and myocardial apoptosis, which were associated with PPARα upregulation. Pretreatment with GW6471 abolished the abovementioned protective effects induced by MG53.

Conclusions

Both MG53 and PPARα were downregulated after sepsis shock. MG53 supplement protects the heart against SIMD by upregulating PPARα expression. Our results provide a new treatment strategy for SIMD.

Heart Dysfunction in Sepsis

Cardiac involvement during sepsis frequently occurs. A series of molecules induces a set of changes at the cellular level that result in the malfunction of the myocardium. The understanding of these molecular alterations has simultaneously promoted the implementation of diagnostic strategies that are much more precise and allowed the advance of the therapeutics. The heart is a vital organ for survival. Its well-being ensures the adequate supply of essential elements for organs and tissues.

Neuregulin‑1: An underlying protective force of cardiac dysfunction in sepsis (Review)

Neuregulin-1 (NRG-1) is a type of epidermal growth factor‑like protein primarily distributed in the nervous and cardiovascular systems. When sepsis occurs, the incidence of cardiac dysfunction in myocardial injury is high and the mechanism is complicated. It directly causes myocardial cell damage, whilst also causing damage to the structure and function of myocardial cells, weakening of endothelial function and coronary microcirculation, autonomic dysfunction, and activation of myocardial inhibitory factors. Studies investigating NRG‑1 have been performed using a variety of methods, including in vitro models, and animal and human clinical trials; however, the results are not consistent. NRG‑1/ErbBs signaling is involved in a variety of cardiac processes, from the development of the myocardium and cardiac conduction systems to the promotion of angiogenesis in cardiomyocytes, and in cardio‑protective effects during injury. NRG‑1 may exert a multifaceted cardiovascular protective effect by activating NRG‑1/ErbBs signaling and regulating multiple downstream signaling pathways, thereby improving myocardial cell dysfunction in sepsis, and protecting cardiomyocytes and endothelial cells. It may alleviate myocardial microvascular endothelial injury in sepsis; its anti‑inflammatory effects inhibit the production of myocardial inhibitory factors in sepsis, improve myocardial ischemia, decrease oxidative stress, regulate the disruption to the homeostasis of the autonomic nervous system, improve diastolic function, and offer protective effects at multiple target sites. As the mechanism of action of NRG‑1 intersects with the pathways involved in the pathogenesis of sepsis, it may be applicable as a treatment strategy to numerous pathological processes in sepsis.

Protective effects of rolipram on endotoxic cardiac dysfunction via inhibition of the inflammatory response in cardiac fibroblasts

BACKGROUND

Cardiac fibroblasts, regarded as the immunomodulatory hub of the heart, have been thought to play an important role during sepsis-induced cardiomyopathy (SIC). However, the detailed molecular mechanism and targeted therapies for SIC are still lacking. Therefore, we sought to investigate the likely protective effects of rolipram, an anti-inflammatory drug, on lipopolysaccharide (LPS)-stimulated inflammatory responses in cardiac fibroblasts and on cardiac dysfunction in endotoxic mice.

METHOD

Cardiac fibroblasts were isolated and stimulated with 1 μg/ml LPS for 6 h, and 10 μmol/l rolipram was administered for 1 h before LPS stimulation. mRNA levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) in fibroblasts and their protein concentrations in supernatant were measured with real-time PCR (rt-PCR) and enzyme-linked immunosorbent assay, respectively. The expression of dual specificity phosphatase 1 (DUSP1), an endogenous negative regulator that inactivates MAPK-mediated inflammatory pathways, was also measured by rt-PCR and western blotting. DUSP1-targeted small interfering RNA (siRNA) was used to examine the specific role of DUSP1. To evaluate the role of rolipram in vivo, an endotoxic mouse model was established by intraperitoneal injection of 15 mg/kg LPS, and 10 mg/kg rolipram was intraperitoneally injected 1 h before LPS injection. mRNA and protein levels of inflammatory cytokines and DUSP1 in heart, inflammatory cell infiltration and cardiac function were all examined at 6 h after LPS injection.

RESULTS

The results showed that LPS could increase the expression and secretion of inflammatory cytokines and decrease the transcription and expression of DUSP1 in cardiac fibroblasts. However, rolipram pretreatment significantly reversed the LPS-induced downregulation of DUSP1 and inhibited LPS-induced upregulation and secretion of TNF-α and IL-6 but not IL-1β. Moreover, DUSP1-targeted siRNA experiments indicated that the protective effect of rolipram on inflammatory response was specific dependent on DUSP1 expression. Moreover, rolipram could further reduce inflammatory cell infiltration scores as shown by pathological analysis and increase the ejection fraction (EF) detected with echocardiography in the hearts of endotoxic mice.

CONCLUSIONS

Rolipram could improve endotoxin-induced cardiac dysfunction by upregulating DUSP1 expression to inhibit the inflammatory response in cardiac fibroblasts, which may be a potential treatment for SIC.

Avaliação da deformação miocárdica pela ecocardiografia feature tracking em gatos com defeito perimembranoso do septo ventricular

RESUMO O desenvolvimento de novas ferramentas, como a ecocardiografia bidimensional feature tracking (2D-FTI), permite diagnosticar, de forma precoce, se há disfunção miocárdica em doenças cardíacas, inclusive as congênitas. O defeito septal ventricular (DSV) é a alteração congênita mais observada em felinos, no entanto pouco se sabe sobre a disfunção cardíaca nessa cardiopatia, especialmente em animais assintomáticos. O objetivo deste estudo foi avaliar, por meio do 2D-FTI, a deformação miocárdica ventricular esquerda pela mensuração dos índices ecocardiográficos strain (St) e strain rate (StR) radial, circunferencial e longitudinal, em gatos saudáveis e com DSV. Foram avaliados 12 gatos saudáveis e seis gatos com DSV para obtenção de St e StR em diversos segmentos miocárdicos. No sentido longitudinal, houve diferença estatística (P<0,05) para os segmentos septal basal, mediano e apical epicárdicos (P=0,0017; P<0,0001; P=0,0288), lateral mediano epicárdico (P=0,0327), septal mediano endocárdico (P=0,0035), lateral mediano endocárdico (P=0,0461), St epicárdico (P=0,0250) e St global (P=0,0382). Também houve diferença no segmento lateral mediano circunferencial endocárdico (P=0,0248), lateral mediano radial (St: P=0,0409; StR: P=0,0166) e posterior mediano radial (P=0,0369). O estudo evidenciou que, mesmo em animais assintomáticos com DSV, há redução na deformação miocárdica ventricular principalmente no sentido longitudinal, demonstrando maior vulnerabilidade dessas fibras.

Mythical metrics and methods: Needed paradigm shift in disease recognition and therapy

Current medicine is practiced in an organ-based, function-appraised manner with less attention paid to the tissue characteristics of the appraised organs. The fundamentals of this paradigm have been the product of an oversimplified and often layman-based perceptions of the studied organ over the years. These perceptions drove the current definitions of normality and abnormality, parameters used in the diagnosis of the disease, goals of treatment and studied outcomes. Despite the explosive advancement in technology that could have potentially changed our 'upstream' thinking, practitioners remain captives of these old beliefs and have streamlined current technology in a 'downstream' fashion; in the form of goal-directed protocols, and engineering systems that would study their implementations. As a result, diseases continue to evolve, become more resistant to therapy, late to diagnose, and with a persistent worsening of outcomes. With a primarily focus on the heart and from an anesthesiologist prospective, we challenge the fundamentals of the current paradigm from an 'upstream' prospective. We challenge the current 'territorial' definitions of the organs studied, the current terminology of some diseases, the parameters used in their diagnosis, the diagnostic modalities used and their goals of treatment. We illustrate some examples when the current collective 'myth' meets the 'reality' in an acute care setting, further clarifying the limitations of the current paradigm. We also, provide a theoretical hypothesis of what we believe to be a potential substitute of the current paradigm. Our theory redefines disease from an organ-based functional phenomenon to a structural-based tissue phenomenon, calling for an integrative and holistic approach of tissue assessment rather than a discrete approach that may potentially obscure the interaction of non-appraised organs. We also believe in redirecting technology in an upstream direction to better redefine and early detect diseases rather than submitting to generationally inherited beliefs. Whereas we have started some of our research on our proposed paradigm, our theoretical framework remains to be thought-provoking, and hypothesis-generating at the present time.

O-GlcNAc stimulation: A new metabolic approach to treat septic shock

Septic shock is a systemic inflammation associated with cell metabolism disorders and cardiovascular dysfunction. Increases in O-GlcNAcylation have shown beneficial cardiovascular effects in acute pathologies. We used two different rat models to evaluate the beneficial effects of O-GlcNAc stimulation at the early phase of septic shock. Rats received lipopolysaccharide (LPS) to induce endotoxemic shock or saline (control) and fluid resuscitation (R) with or without O-GlcNAc stimulation (NButGT-10 mg/kg) 1 hour after shock induction. For the second model, rats received cecal ligature and puncture (CLP) surgery and fluid therapy with or without NButGT. Cardiovascular function was evaluated and heart and blood samples were collected and analysed. NButGT treatment efficiently increased total O-GlcNAc without modification of HBP enzyme expression.Treatment improved circulating parameters and cardiovascular function in both models, and restored SERCA2a expression levels. NButGT treatment also reduced animal mortality. In this study, we demonstrate that in septic shock O-GlcNAc stimulation improves global animal and cardiovascular function outcomes associated with a restoration of SERCA2a levels. This pre-clinical study opens avenues for a potential therapy of early-stage septic shock.

Indigo Fruits Ingredient, Aucubin, Protects against LPS-Induced Cardiac Dysfunction in Mice

Aucubin (AUB), which is extracted from Eucommia ulmoides Oliver seeds, has been found to possess anti-inflammatory and antiapoptotic properties. Recent studies have indicated that inflammation, oxidative stress, and apoptosis are involved in the pathophysiology of lipopolysaccharide (LPS)-induced cardiac dysfunction. Our study aimed to investigate the effect of AUB on LPS-induced acute cardiac injury. Male C57BL/6 mice were injected with LPS (one 6 mg/kg injection) to induce cardiac dysfunction without or with AUB pretreatment (20 or 80 mg/kg per day) for 1 week. We found that AUB ameliorated cardiac dysfunction, inflammation, oxidative stress, and apoptosis induced by LPS stimulation. Mechanistically, AUB inhibited LPS-induced oxidative stress by decreasing reactive oxygen species and thioredoxin interaction protein (TXNIP) levels. Moreover, AUB suppressed LPS-induced inflammation and apoptosis by reducing nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3)/apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC)/caspase-1 inflammasome formation. Overexpression of NLRP3 in cardiomyocytes attenuated the protective effects of AUB. Interestingly, NLRP3 deficiency ameliorated cardiac function and reduced the inflammatory response and oxidative stress after LPS insult in mice, whereas AUB could not further prevent LPS-induced cardiac dysfunction in NLRP3-deficient mice. In summary, AUB exerts a protective effect against LPS-induced inflammation, oxidative stress, and apoptosis in vivo and in vitro by regulating the TXNIP pathway and inactivating the NLRP3/ASC/caspase-1 inflammasome. Hence, AUB may be a promising agent against LPS-induced cardiac dysfunction. SIGNIFICANCE STATEMENT: Aucubin exerts a protective effect against lipopolysaccharide-induced cardiac dysfunction by regulating nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 inflammasome.

Temporally Distinct Regulation of Pathways Contributing to Cardiac Proteostasis During the Acute and Recovery Phases of Sepsis

BACKGROUND

Cardiac dysfunction is a common manifestation of sepsis and is associated with early increases in inflammation and decreases in myocardial protein synthesis. However, little is known regarding the molecular mechanisms regulating protein homeostasis during the recovery phase after the removal of the septic nidus. Therefore, the purpose of this study was to investigate diverse signal transduction pathways that regulate myocardial protein synthesis and degradation.

METHODS

Adult male C57BL/6 mice were used to identify potential mechanisms mediating the acute (24 h) effect of cecal ligation and puncture as well as long-term changes that manifest during the chronic (10 days) recovery phase.

RESULTS

Sepsis acutely decreased cardiac protein synthesis that was associated with reduced phosphorylation of S6K1/S6 but not 4E-BP1. Sepsis also decreased proteasome activity, although with no change in MuRF1 and atrogin-1 mRNA expression. Sepsis acutely increased apoptosis (increased caspase-3 and PARP cleavage), autophagosome formation (increased LC3B-II), and canonical inflammasome activity (increased NLRP3, TMS1, cleaved caspase-1). In contrast, during the recovery phase, independent of a difference in food consumption, global protein synthesis was increased, the early repression in proteasome activity was restored to basal levels, whereas stimulation of apoptosis, autophagosome formation, and the canonical inflammasome pathway had abated. However, during recovery there was a selective stimulation of the noncanonical inflammasome pathway as evidenced by activation of caspase-11 with cleavage of Gasdermin D.

CONCLUSIONS

These data demonstrate a temporally distinct homeostatic shift in the cardiac proteostatic response to acute infection and recovery.

MKP1 overexpression reduces TNF-α-induced cardiac injury via suppressing mitochondrial fragmentation and inhibiting the JNK-MIEF1 pathways

Mitochondrial stress has been acknowledged as the pathogenesis for tumor necrosis factor-α (TNF-α)-induced septic cardiomyopathy. Recently, MAP kinase phosphatase 1 (MKP1) downregulation and mitochondrial fragmentation modulate the mitochondrial stress via multiple molecular mechanisms. Thereby, the goal of our current work is to figure out the functional role of mitochondrial fragmentation in TNF-α-induced septic cardiomyopathy. Our results exhibited that MKP1 expression was significantly repressed in hearts treated by TNF-α. Overexpression of MKP1 sustained cardiac function and attenuated cardiomyocytes death in TNF-α-treated hearts. At the molecular levels, decreased MKP1 induced mitochondrial stress, as indicated by mitochondrial calcium overloading, mitochondrial oxidative stress, mitochondrial antioxidant downregulation, mitochondrial membrane potential reduction, mitochondrial bioenergetics suppression, mitochondrial proapoptotic factors liberation, and caspase-9 apoptotic pathway activation. To the end, we illustrated that MKP1-modulated mitochondrial stress via mitochondrial fragmentation; reactivation of mitochondrial fragmentation abolished the protective effect of MKP1 overexpression on mitochondrial function. Further, MKP1 affected mitochondrial division in a mechanism through the JNK-MIEF1 axis. Blockade of JNK pathway abolished the regulatory actions of MKP1 on mitochondrial division. Altogether, our results identify MKP1 as a novel cardioprotective factor in TNF-α-related septic cardiomyopathy via affecting mitochondrial division by the way of JNK-MIEF1 signaling pathway. Therefore, MKP1 expression, mitochondrial fragmentation modification, and JNK-MIEF1 pathway modulation may be considered as potential therapeutic targets for the treatment of cardiac injury induced by sepsis.