Sepsis-Induced Myocardial Dysfunction (SIMD): the Pathophysiological Mechanisms and Therapeutic Strategies Targeting Mitochondria

JAK2 inhibitor protects the septic heart through enhancing mitophagy in cardiomyocytes

Sepsis-induced myocardial dysfunction (SIMD) is a severe complication in sepsis, manifested as myocardial systolic dysfunction, which is associated with poor prognosis and higher mortality. Mitophagy, a self-protective mechanism maintaining cellular homeostasis, plays an indispensable role in cardioprotection. This study aimed to unveil the cardioprotective effects of Baricitinib on LPS-induced myocardial dysfunction and its effect on mitophagy. Herein, we demonstrated that LPS induced severe myocardial dysfunction and initiated mitophagy in septic mice hearts. Despite the initiation of mitophagy, a significant number of apoptotic cells and damaged mitochondria persisted in the myocardium, and myocardial energy metabolism remained impaired, indicating that the limited mitophagy was insufficient to mitigate LPS-induced damage. The JAK2-AKT-mTOR signaling pathway is activated in LPS-induced cardiomyocytes and in the hearts of septic mice. Baricitinib administration remarkably improved cardiac function, suppressed systemic inflammatory response, attenuated histopathological changes, inhibited cardiac cell apoptosis and alleviated myocardial damage in septic mice. Furthermore, Baricitinib treatment significantly enhanced PINK1-Parkin-mediated mitophagy, increased autophagosomes, decreased impaired mitochondria, and restored myocardial energy metabolism. Mechanically, the limited mitophagy in septic myocardium was associated with increased p-ULK1 (Ser757), which was regulated by p-mTOR. Baricitinib reduced p-ULK1 (Ser757) and enhanced mitophagy by inhibiting the JAK2-AKT-mTOR signaling pathway. Inhibition of mitophagy with Mdivi-1 reversed the cardiac protective and anti-inflammatory effects of Baricitinib in septic mice. These findings suggest that Baricitinib attenuates SIMD by enhancing mitophagy in cardiomyocytes via the JAK2-AKT-mTOR signaling pathway, providing a novel mechanistic and therapeutic insight into the SIMD.

The Protective Effects of Ruscogenin Against Lipopolysaccharide-Induced Myocardial Injury in Septic Mice

ABSTRACT

Sepsis-induced myocardial dysfunction commonly occurs in individuals with sepsis and is a severe complication with high morbidity and mortality rates. This study aimed to investigate the effects and potential mechanisms of the natural steroidal sapogenin ruscogenin (RUS) against lipopolysaccharide (LPS)-induced myocardial injury in septic mice. We found that RUS effectively alleviated myocardial pathological damage, normalized cardiac function, and increased survival in septic mice. RNA sequencing demonstrated that RUS administration significantly inhibited the activation of the NOD-like receptor signaling pathway in the myocardial tissues of septic mice. Subsequent experiments further confirmed that RUS suppressed myocardial inflammation and pyroptosis during sepsis. In addition, cultured HL-1 cardiomyocytes were challenged with LPS, and we observed that RUS could protect these cells against LPS-induced cytotoxicity by suppressing inflammation and pyroptosis. Notably, both the in vivo and in vitro findings indicated that RUS inhibited NOD-like receptor protein-3 (NLRP3) upregulation in cardiomyocytes stimulated with LPS. As expected, knockdown of NLRP3 blocked the LPS-induced activation of inflammation and pyroptosis in HL-1 cells. Furthermore, the cardioprotective effects of RUS on HL-1 cells under LPS stimulation were abolished by the novel NLRP3 agonist BMS-986299. Taken together, our results suggest that RUS can alleviate myocardial injury during sepsis, at least in part by suppressing NLRP3-mediated inflammation and pyroptosis, highlighting the potential of this molecule as a promising candidate for sepsis-induced myocardial dysfunction therapy.

Dapagliflozin attenuates LPS-induced myocardial injury by reducing ferroptosis

Septic cardiomyopathy is a severe cardiovascular disease with a poor prognosis. Previous studies have reported the involvement of ferroptosis in the pathogenesis of septic cardiomyopathy. SGLT2 inhibitors such as dapagliflozin have been demonstrated to improve ischemia-reperfusion injury by alleviating ferroptosis in cardiomyocyte. However, the role of dapagliflozin in sepsis remains unclear. Therefore, our study aims to investigate the therapeutic effects of dapagliflozin on LPS-induced septic cardiomyopathy. Our results indicate that dapagliflozin improved cardiac function in septic cardiomyopathy experimental mice. Mechanistically, dapagliflozin works by inhibiting the translation of key proteins involved in ferroptosis, such as GPX4, FTH1, and SLC7A11. It also reduces the transcription of lipid peroxidation-related mRNAs, including PTGS2 and ACSL4, as well as iron metabolism genes TFRC and HMOX1.

S100A9 as a Key Myocardial Injury Factor Interacting with ATP5 Exacerbates Mitochondrial Dysfunction and Oxidative Stress in Sepsis-Induced Cardiomyopathy

Purpose

Sepsis-induced cardiomyopathy (SICM) is a prevalent cardiac dysfunction caused by sepsis. Mitochondrial dysfunction is a crucial pathogenic factor associated with adverse cardiovascular adverse events; however, research on SICM remains insufficient.

Methods

To investigate the factors contributing to the pathological progression of SICM, we performed a comprehensive analysis of transcriptomic data from the GEO database using bioinformatics and machine learning techniques. CRISPR-Cas9 S100A9 knockout mice and primary cardiomyocytes were exposed to lipopolysaccharide to simulate SICM. Transcriptome analysis and mass spectrometry of primary cardiomyocytes were used to determine the potential pathogenic mechanisms of S100A9. The mitochondrial ultrastructure and mitochondrial membrane potential (MMP) were detected using transmission electron microscopy and flow cytometry, respectively. Pink1/Parkin and Drp1 proteins were detected using Western blotting to evaluate mitochondrial autophagy and division. The mtDNA and mRNA levels of mitochondrial transcription factors and synthases were evaluated using real-time polymerase chain reaction.

Results

Bioinformatics analysis identified 12 common differentially expressed genes, including SERPINA3N, LCN2, MS4A6D, LRG1, OSMR, SOCS3, FCGR2b, S100A9, S100A8, CASP4, ABCA8A, and NFKBIZ. Significant S100A9 upregulation was closely associated with myocardial injury exacerbation and cardiac function deterioration. GSEA revealed that myocardial contractile function, oxidative stress, and mitochondrial function were significantly affected by S100A9. Knocking out S100A9 alleviates the inflammatory response and mitochondrial dysfunction. The interaction of S100A9 with ATP5 enhanced mitochondrial division and autophagy, inhibited MMP and ATP synthesis, and induced oxidative stress, which are related to the Nlrp3-Nfkb-Caspase1 and Drp1-Pink1-Parkin signaling pathways. The expression of mitochondrial transcription factors (TFAM and TFBM) and ATP synthetases (ATP6 and ATP8, as well as COX1, COX2, and COX3) was further suppressed by S100A9 in SICM. Targeted S100A9 inhibition by paquinimod partially reversed myocardial mitochondrial dysfunction and oxidative stress.

Conclusion

The interaction of S100A9 with ATP5 exacerbates myocardial damage in sepsis by inducing mitochondrial dysfunction and oxidative stress.

The emerging role of mtDNA release in sepsis: Current evidence and potential therapeutic targets

Sepsis is a systemic inflammatory reaction caused by infection, and severe sepsis can develop into septic shock, eventually leading to multiorgan dysfunction and even death. In recent years, studies have shown that mitochondrial damage is closely related to the occurrence and development of sepsis. Recent years have seen a surge in concern over mitochondrial DNA (mtDNA), as anomalies in this material can lead to cellular dysfunction, disruption of aerobic respiration, and even death of the cell. In this review, we discuss the latest findings on the mechanisms of mitochondrial damage and the molecular mechanisms controlling mitochondrial mtDNA release. We also explored the connection between mtDNA misplacement and inflammatory activation. Additionally, we propose potential therapeutic targets of mtDNA for sepsis treatment.

Curcumin simultaneously improves mitochondrial dynamics and myocardial cell bioenergy after sepsis via the SIRT1-DRP1/PGC-1α pathway

Septic cardiomyopathy (SCM) is associated with an imbalance in mitochondrial quality and high mortality rates, with no effective treatment developed to date. Curcumin provides antioxidant, anti-inflammatory, cardiovascular, and mitochondrial protection. However, curcumin has not been confirmed to improve cardiac dysfunction in sepsis. We hypothesized that curcumin can reduce abnormal inflammatory responses by improving mitochondrial function as a novel mechanism to improve SCM. To explore this hypothesis, we used an in vivo male C57BL/6 mouse sepsis model and an in vitro model of lipopolysaccharide-stimulated HL-1 cells. The effects of curcumin on sepsis-induced cardiac dysfunction, inflammatory responses, and mitochondrial quality of cardiac cells were observed using quantitative polymerase chain reaction, western blotting, echocardiography, and transmission electron microscopy. Curcumin activated sirtuin 1 (SIRT1); increased expression of the mitochondrial biogenesis-related genes Pgc1α, Tfam, and Nrf2; reduced dynamin-related protein 1 translocation from the cytoplasm to mitochondria; and restored the mitochondrial morphology and function in cardiac cells. Accordingly, curcumin protected heart function after septic shock and alleviated the effects of SCM. SIRT1 knockdown reversed the protective effects of curcumin on mitochondria. Therefore, curcumin promotes mitochondrial biogenesis and inhibits mitochondrial fragmentation by activating SIRT1, thereby improving the mitochondrial quality and reducing oxidative stress in cardiomyocytes and sepsis-induced cardiac dysfunction. These findings provide new evidence supporting the use of curcumin to treat SCM.

Utility of NICaS Non-Invasive Hemodynamic Monitoring in Critically Ill Patients with COVID-19

(1) Background: COVID-19 presented many challenges to effective treatments, such as managing cardiovascular insufficiency while mitigating risks to healthcare providers. This study utilized NICaS, a non-invasive hemodynamic monitor that provides advanced data via whole-body impedance analysis. We investigated the associated trends in hemodynamic parameters obtained by the NICaS device and their correlation with in-hospital all-cause mortality during COVID-19 hospitalization in the intensive care unit. (2) Methods: Data from 29 patients with COVID-19 admitted to the intensive care unit and monitored with NICaS between April 2020 and February 2021 were analyzed retrospectively. (3) Results: Decreasing cardiac output and cardiac power were significantly associated with death. Total peripheral resistance was significantly increasing in non-survivors as was total body water percentage. Those admitted with a heart rate above 90 beats per minute had a significantly reduced survival. (4) Conclusions: Non-invasive hemodynamic monitoring via the NICaS device is simple and effective in evaluating critically ill patients with COVID-19 and may help guide clinical management via remote monitoring. Controlling tachycardia may help ensure adequate oxygen supply-demand ratio. A hint toward a beneficiary effect of a restrictive fluid balance may be observed.

Protective effect of zerumbone on sepsis-induced acute lung injury through anti-inflammatory and antioxidative activity via NF-κB pathway inhibition and HO-1 activation

Sepsis is a systemic illness for which there are no effective preventive or therapeutic therapies. Zerumbone, a natural molecule, has anti-oxidative and anti-inflammatory properties that may help to prevent sepsis. In the present study, we have assessed the protective effect of zerumbone against sepsis-induced acute lung injury (ALI) and its underlying mechanisms. During the experiment, mice were divided into five groups: a sham group, a sepsis-induced ALI group, and three sepsis groups that are pre-treated with zerumbone at different concentrations. We found that zerumbone greatly decreased the sepsis-induced ALI using histological investigations. Also, zerumbone treatment reduced the sepsis-induced inflammatory cytokine concentrations as well as the number of infiltrating inflammatory cells in BALF compared to non-treated sepsis animals. The zerumbone-pretreated sepsis groups had reduced pulmonary myeloperoxidase (MPO) activity than the sepsis groups. Moreover, the mechanism underlying the protective action of zerumbone on sepsis is accomplished by the activation of antioxidant genes such as nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), superoxide dismutase (SOD), and heme oxygenase 1 (HO-1). The obtained results revealed that zerumbone inhibited the sepsis-induced ALI through its anti-inflammatory and antioxidative activity via inhibition of the NF-κB pathway and activation of HO-1 pathway. Our findings demonstrate that zerumbone pretreatment suppresses sepsis-induced ALI via antioxidative activities and anti-inflammatory, implying that zerumbone could be a viable preventive agent for sepsis-induced ALI.

Molecular hydrogen attenuates sepsis-induced cardiomyopathy in mice by promoting autophagy

BACKGROUND

Approximately 40 to 60% of patients with sepsis develop sepsis-induced cardiomyopathy (SIC), which is associated with a substantial increase in mortality. We have found that molecular hydrogen (H2) inhalation improved the survival rate and cardiac injury in septic mice. However, the mechanism remains unclear. This study aimed to explore the regulatory mechanism by which hydrogen modulates autophagy and its role in hydrogen protection of SIC.

METHODS

Cecal ligation and puncture (CLP) was used to induce sepsis in adult C57BL/6J male mice. The mice were randomly divided into 4 groups: Sham, Sham + 2% hydrogen inhalation (H2), CLP, and CLP + H2 group. The 7-day survival rate was recorded. Myocardial pathological scores were calculated. Myocardial troponin I (cTnI) levels in serum were detected, and the levels of autophagy- and mitophagy-related proteins in myocardial tissue were measured. Another four groups of mice were also studied: CLP, CLP + Bafilomycin A1 (BafA1), CLP + H2, and CLP + H2 + BafA1 group. Mice in the BafA1 group received an intraperitoneal injection of the autophagy inhibitor BafA1 1 mg/kg 1 h after operation. The detection indicators remained the same as before.

RESULTS

The survival rate of septic mice treated with H2 was significantly improved, myocardial tissue inflammation was improved, serum cTnI level was decreased, autophagy flux was increased, and mitophagy protein content was decreased (P < 0.05). Compared to the CLP + H2 group, the CLP + H2 + BafA1 group showed a decrease in autophagy level and 7-day survival rate, an increase in myocardial tissue injury and cTnI level, which reversed the protective effect of hydrogen (P < 0.05).

CONCLUSION

Hydrogen exerts protective effect against SIC, which may be achieved through the promotion of autophagy and mitophagy.

Bisphosphoglycerate mutase predicts myocardial dysfunction and adverse outcome in sepsis: an observational cohort study

BACKGROUND

Sepsis not only causes inflammation, but also damages the heart and increases the risk of death. The glycolytic pathway plays a crucial role in the pathogenesis of sepsis-induced cardiac injury. This study aims to investigate the value of bisphosphoglycerate mutase (BPGM), an intermediate in the glycolytic pathway, in evaluating cardiac injury in septic patients and predicting poor prognosis in sepsis.

METHODS

This prospective study included 85 patients with sepsis. Serum BPGM was measured at the time of enrollment, and the patients were divided into a BPGM-positive group (n = 35) and a BPGM-negative group (n = 50) according to their serum BPGM levels. Baseline clinical and echocardiographic parameters, and clinical outcomes were analyzed and compared between the two groups. Kaplan-Meier analysis was used to compare the 28-day survival rate between BPGM-negative and BPGM-positive patients. Multivariate logistic regression analysis was conducted to explore the independent risk factors for 28-day mortality in septic patients. The predictive value of serum BPGM for sepsis-induced myocardial injury and poor prognosis in sepsis was evaluated using receiver operating characteristic (ROC)curve analysis.

RESULT

The serum level of BPGM was significantly higher in patients who died within 28 days compared to survivors (p < 0.001). Kaplan-Meier analysis showed that serum BPGM-positive sepsis patients had a significantly shorter 28-day survival time (p < 0.001). Multivariate logistic regression analysis showed that serum BPGM (OR = 9.853, 95%CI 1.844-52.655, p = 0.007) and left ventricular ejection fraction-simpson(LVEF-S) (OR = 0.032, 95% CI 0.002-0.43, p = 0.009) were independent risk factors for 28-day mortality in sepsis patients. Furthermore, BPGM levels was negatively correlated with LVEF-S (p = 0.005) and positively correlated with the myocardial performance (Tei) index (p < 0.001) in sepsis patients. ROC curve analysis showed that serum BPGM was a good predictor of septic myocardial injury and 28-day mortality in sepsis patients.

CONCLUSION

The level of BPGM in the serum of sepsis patients can serve as a monitoring indicator for myocardial injury, with its high level indicating the occurrence of secondary myocardial injury events and adverse outcomes in sepsis patients.

So close, yet so far away: the relationship between MAM and cardiac disease

Mitochondria-associated membrane (MAM) serve as crucial contact sites between mitochondria and the endoplasmic reticulum (ER). Recent research has highlighted the significance of MAM, which serve as a platform for various protein molecules, in processes such as calcium signaling, ATP production, mitochondrial structure and function, and autophagy. Cardiac diseases caused by any reason can lead to changes in myocardial structure and function, significantly impacting human health. Notably, MAM exhibits various regulatory effects to maintain cellular balance in several cardiac diseases conditions, such as obesity, diabetes mellitus, and cardiotoxicity. MAM proteins independently or interact with their counterparts, forming essential tethers between the ER and mitochondria in cardiomyocytes. This review provides an overview of key MAM regulators, detailing their structure and functions. Additionally, it explores the connection between MAM and various cardiac injuries, suggesting that precise genetic, pharmacological, and physical regulation of MAM may be a promising strategy for preventing and treating heart failure.

Metabolism Serves as a Bridge Between Cardiomyocytes and Immune Cells in Cardiovascular Diseases

Metabolic disorders of cardiomyocytes play an important role in the progression of various cardiovascular diseases. Metabolic reprogramming can provide ATP to cardiomyocytes and protect them during diseases, but this transformation also leads to adverse consequences such as oxidative stress, mitochondrial dysfunction, and eventually aggravates myocardial injury. Moreover, abnormal accumulation of metabolites induced by metabolic reprogramming of cardiomyocytes alters the cardiac microenvironment and affects the metabolism of immune cells. Immunometabolism, as a research hotspot, is involved in regulating the phenotype and function of immune cells. After myocardial injury, both cardiac resident immune cells and heart-infiltrating immune cells significantly contribute to the inflammation, repair and remodeling of the heart. In addition, metabolites generated by the metabolic reprogramming of immune cells can further affect the microenvironment, thereby affecting the function of cardiomyocytes and other immune cells. Therefore, metabolic reprogramming and abnormal metabolite levels may serve as a bridge between cardiomyocytes and immune cells, leading to the development of cardiovascular diseases. Herein, we summarize the metabolic relationship between cardiomyocytes and immune cells in cardiovascular diseases, and the effect on cardiac injury, which could be therapeutic strategy for cardiovascular diseases, especially in drug research.

The Apelin/APJ System: A Potential Therapeutic Target for Sepsis

Apelin is the native ligand for the G protein-coupled receptor APJ. Numerous studies have demonstrated that the Apelin/APJ system has positive inotropic, anti-inflammatory, and anti-apoptotic effects and regulates fluid homeostasis. The Apelin/APJ system has been demonstrated to play a protective role in sepsis and may serve as a promising therapeutic target for the treatment of sepsis. Better understanding of the mechanisms of the effects of the Apelin/APJ system will aid in the development of novel drugs for the treatment of sepsis. In this review, we provide a brief overview of the physiological role of the Apelin/APJ system and its role in sepsis.

Golgi Protein 73 Promotes LPS-Induced Cardiac Dysfunction via Mediating Myocardial Apoptosis and Autophagy

ABSTRACT

Sepsis-induced cardiac dysfunction represents a major cause of high mortality in intensive care units with limited therapeutic options. Golgi protein 73 (GP73) has been implicated in various diseases. However, the role of GP73 in lipopolysaccharide (LPS)-induced cardiac dysfunction is unclear. In this study, we established a sepsis-induced cardiac dysfunction model by LPS administration in wild-type and GP73 knockout ( GP73-/- ) mice. We found that GP73 was increased in LPS-treated mouse hearts and LPS-cultured neonatal rat cardiomyocytes (NRCMs). Knockout of GP73 alleviated myocardial injury and improved cardiac dysfunction. Moreover, depletion of GP73 in NRCMs relieved LPS-induced cardiomyocyte apoptosis and activated myocardial autophagy. Therefore, GP73 is a negative regulator in LPS-induced cardiac dysfunction by promoting cardiomyocyte apoptosis and inhibiting cardiomyocyte autophagy.

Current insight on the mechanisms of programmed cell death in sepsis-induced myocardial dysfunction

Sepsis is a clinical syndrome characterized by a dysregulated host response to infection, leading to life-threatening organ dysfunction. It is a high-fatality condition associated with a complex interplay of immune and inflammatory responses that can cause severe harm to vital organs. Sepsis-induced myocardial injury (SIMI), as a severe complication of sepsis, significantly affects the prognosis of septic patients and shortens their survival time. For the sake of better administrating hospitalized patients with sepsis, it is necessary to understand the specific mechanisms of SIMI. To date, multiple studies have shown that programmed cell death (PCD) may play an essential role in myocardial injury in sepsis, offering new strategies and insights for the therapeutic aspects of SIMI. This review aims to elucidate the role of cardiomyocyte's programmed death in the pathophysiological mechanisms of SIMI, with a particular focus on the classical pathways, key molecules, and signaling transduction of PCD. It will explore the role of the cross-interaction between different patterns of PCD in SIMI, providing a new theoretical basis for multi-target treatments for SIMI.

Gossypol improves myocardial dysfunction caused by sepsis by regulating histone acetylation

Gossypol is a polyphenol from the cotton plant with anti-inflammatory and anti-oxidation activities and can also function as a histone deacetylase (HDAC) inhibitor. Sepsis is an inflammatory disease with high mortality. Inflammation, oxidative stress, and epigenetic factors are involved in sepsis and its complications. The biological activities of gossypol strongly suggest the potential effects of gossypol on sepsis. In the present study, the beneficial effects of gossypol on sepsis were evaluated. We established a cecal ligation and puncture (CLP) mouse model of sepsis and treated CLP mice with gossypol. The survival rate, serum level of myocardial injury markers, and myocardial level of oxidation markers were measured. We also administered gossypol to lipopolysaccharide (LPS)-treated primary cardiomyocytes. The production of pro-inflammatory cytokines, activation of protein kinase B (AKT) and IκB kinase (IKK), acetylation of histone, and expression of HDACs were measured. Gossypol prevented the death of CLP mice and ameliorated myocardial damage in CLP mice. Moreover, gossypol decreased oxidative factors, while promoting antioxidant production in CLP mice. Gossypol prevented LPS and cytosine-phosphate-guanosine-induced expression of pro-inflammatory cytokines, suppressed LPS-induced activation of AKT and IKK, inhibited histone acetylation, and decreased the expression of HDACs. In conclusion, gossypol ameliorates myocardial dysfunction in mice with sepsis.

Synthesis and protective effect of pyrazole conjugated imidazo[1,2-a]pyrazine derivatives against acute lung injury in sepsis rats via attenuation of NF-κB, oxidative stress, and apoptosis

The current work was conducted to elucidate the pharmacological effect of pyrazole-conjugated imidazo[1,2-a]pyrazine derivatives against acute lung injury in rats in sepsis and their mechanism of action. Various pyrazole-conjugated imidazo[1,2-a]-pyrazine derivatives have been synthesized in a straightforward synthetic route. They exhibited a diverse range of inhibitory activity against NF-ĸB with IC 50 ranging from 1 to 94 µmol L-1. Among them, compound 3h [(4-(4-((4-hydroxyphenyl)sulfonyl) phenyl)-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazol-1-yl) (8-(methylamino)imidazo[1,2-a]pyrazin-2-yl)methanone] was identified as the most potent NF-κB inhibitor with IC 50 of 1.02 µmol L-1. None of the synthesized compounds was found cytotoxic to normal cell-line MCF-12A. The pharmacological activity of the most potent NF-ĸB inhibitor 3h was also investigated in cecal ligation and puncture (CLP)-induced sepsis injury of the lung in rats. Compound 3h was administered to rats after induc tion of lung sepsis, and various biochemical parameters were measured. Results suggested that compound 3h significantly reduced lung inflammation and membrane permeability, as evidenced by H&E staining of lung tissues. It substantially reduced the generation of pro-inflammatory cytokines (TNF-α, IL-1B, IL-6) and oxidative stress (MPO, MDA, SOD). It showed attenuation of NF-ĸB and apoptosis in Western blot and annexin--PI assay, resp. Compound 3h also reduced the production of bronchoalveolar lavage fluid from the lung and provided a protective effect against lung injury. Our study showed the pharmacological significance of pyrazole-conjugated imidazo[1,2-a] pyrazine derivative 3h against acute lung injury in sepsis rats.

Stress granule activation attenuates lipopolysaccharide-induced cardiomyocyte dysfunction

BACKGROUND

Sepsis is the leading cause of death in intensive care units. Sepsis-induced myocardial dysfunction, one of the most serious complications of sepsis, is associated with higher mortality rates. As the pathogenesis of sepsis-induced cardiomyopathy has not been fully elucidated, there is no specific therapeutic approach. Stress granules (SG) are cytoplasmic membrane-less compartments that form in response to cellular stress and play important roles in various cell signaling pathways. The role of SG in sepsis-induced myocardial dysfunction has not been determined. Therefore, this study aimed to determine the effects of SG activation in septic cardiomyocytes (CMs).

METHODS

Neonatal CMs were treated with lipopolysaccharide (LPS). SG activation was visualized by immunofluorescence staining to detect the co-localization of GTPase-activating protein SH3 domain binding protein 1 (G3BP1) and T cell-restricted intracellular antigen 1 (TIA-1). Eukaryotic translation initiation factor alpha (eIF2α) phosphorylation, an indicator of SG formation, was assessed by western blotting. Tumor necrosis factor alpha (TNF-α) production was assessed by PCR and enzyme-linked immunosorbent assays. CMs function was evaluated by intracellular cyclic adenosine monophosphate (cAMP) levels in response to dobutamine. Pharmacological inhibition (ISRIB), a G3BP1 CRISPR activation plasmid, and a G3BP1 KO plasmid were employed to modulate SG activation. The fluorescence intensity of JC-1 was used to evaluate mitochondrial membrane potential.

RESULTS

LPS challenge in CMs induced SG activation and resulted in eIF2α phosphorylation, increased TNF-α production, and decreased intracellular cAMP in response to dobutamine. The pharmacological inhibition of SG (ISRIB) increased TNF-α expression and decreased intracellular cAMP levels in CMs treated with LPS. The overexpression of G3BP1 increased SG activation, attenuated the LPS-induced increase in TNF-α expression, and improved CMs contractility (as evidenced by increased intracellular cAMP). Furthermore, SG prevented LPS-induced mitochondrial membrane potential dissipation in CMs.

CONCLUSION

SG formation plays a protective role in CMs function in sepsis and is a candidate therapeutic target.

Mitochondrial transplantation as a novel therapeutic strategy for cardiovascular diseases

Cardiovascular disease (CVD) is the leading cause of noncommunicable disease-related death worldwide, and effective therapeutic strategies against CVD are urgently needed. Mitochondria dysfunction involves in the onset and development of CVD. Nowadays, mitochondrial transplantation, an alternative treatment aimed at increasing mitochondrial number and improving mitochondrial function, has been emerged with great therapeutic potential. Substantial evidence indicates that mitochondrial transplantation improves cardiac function and outcomes in patients with CVD. Therefore, mitochondrial transplantation has profound implications in the prevention and treatment of CVD. Here, we review the mitochondrial abnormalities that occur in CVD and summarize the therapeutic strategies of mitochondrial transplantation for CVD.

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.

Serum mAST/ALT ratio had high predictive value for adverse outcome of severe fever with thrombocytopenia syndrome with severe condition

BACKGROUND

Severe fever with thrombocytopenia syndrome (SFTS) usually demonstrates multi-organ injury with a high mortality rate. This study aimed to investigate associations of serum aspartate/alanine aminotransferase (AST)/ALT, cytosolic AST (cAST)/ALT and mitochondrial AST (mAST)/ALT ratios with the prognosis of SFTS patients.

METHODS

A total of 355 confirmed SFTS patients were included. Clinical and laboratory data were compared between survivors and nonsurvivors. Logistic regression analysis was used to assess the independent risk factors for fatality in all patients and those admitted to the intensive care unit (ICU). The predictive values of the risk factors and constructed risk models were evaluated.

RESULTS

Mean age and biochemical parameters were significantly greater in nonsurvivors than in survivors. In ICU patients, the three ratios, high-sensitivity troponin I (hsTnI), creatine kinase (CK), lactate dehydrogenase (LDH) and α-hydroxybutyrate dehydrogenase (α-HBDH) were elevated markedly in nonsurvivors than in survivors. Multivariate logistic regression analysis showed that age, three ratios and α-HBDH were independent risk factors for mortality in all patients. Only the three ratios were independent risk factors for death in ICU patients. Risk Models (M1, M2 and M3) and simplified models (sMs) containing the three ratios respectively had comparatively high predictive values for fatality in all patients with area under ROC curves (AUCs) > 0.85. In ICU patients, mAST/ALT ratio had the highest predictive value, sensitivity and odds ratio (OR) for mortality among three ratios.

CONCLUSION

AST/ALT, cAST/ALT and mAST/ALT ratios were associated with unfavorable clinical outcome of SFTS. The prognostic value of mAST/ALT ratio was higher in severe cases.

Hydrogen sulfide alleviates lipopolysaccharide-induced myocardial injury through TLR4-NLRP3 pathway

To investigate the effect of hydrogen sulfide (H2S) on myocardial injury in sepsis-induced myocardial dysfunction (SIMD), male C57BL/6 mice were intraperitoneally injected with lipopolysaccharide (LPS) (10 mg/kg, i.p.) to induce cardiac dysfunction without or with the H2S donor sodium hydrosulfide (NaHS) (50 µmol/kg, i.p.) administration 3 h after LPS injection. Six hours after the LPS injection, echocardiography, cardiac hematoxylin and eosin (HE) staining, myocardial damage and inflammatory biomarkers and Western blot results were analyzed. In mice, the administration of LPS decreased left ventricular ejection fraction (LVEF) by 30 % along with lowered H2S levels (35 % reduction). It was observed that cardiac troponin I (cTnI), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1beta (IL-1beta) levels were all increased (by 0.22-fold, 2000-fold and 0.66-fold respectively). HE staining revealed structural damage and inflammatory cell infiltration in the myocardial tissue after LPS administration. Moreover, after 6 h of LPS treatment, toll-like receptor 4 (TLR4) and nod-like receptor protein 3 (NLRP3) expressions were up-regulated 2.7-fold and 1.6-fold respectively. When compared to the septic mice, NaHS enhanced ventricular function (by 0.19-fold), decreased cTnI, TNF-alpha, and IL-1beta levels (by 11 %, 33 %, and 16 % respectively) and downregulated TLR4 and NLRP3 expressions (by 64 % and 31 % respectively). Furthermore, NaHS did not further improve cardiac function and inflammation in TLR4-/- mice or mice in which NLRP3 activation was inhibited by MCC950, after LPS injection. In conclusion, these findings imply that decreased endogenous H2S promotes the progression of SIMD, whereas exogenous H2S alleviates SIMD by inhibiting inflammation via the TLR4-NLRP3 pathway suppression.

Mitochondrial transplantation protects against sepsis-induced myocardial dysfunction by modulating mitochondrial biogenesis and fission/fusion and inflammatory response

BACKGROUND

Sepsis-induced myocardial dysfunction is associated with worse clinical outcomes and high mortality, but no effective therapeutic intervention has been explored, reinforcing the urgent need to develop innovative strategies. Mitochondrial dysfunction underlies the pathogenesis of sepsis-induced myocardial dysfunction. Herein, we assessed the effect of mitochondrial transplantation on sepsis-induced myocardial dysfunction in a rat model of cecal ligation and puncture (CLP)-induced sepsis.

METHODS

Male Wistar rats (n = 80, 12 weeks old, 250-300 g) were divided into groups with/without CLP-induced sepsis receiving mitochondrial transplantation in single or two repetitive injections (1 h or 1 and 7 h post-CLP, respectively). Mitochondria were isolated from donor rats and injected intravenously (400 µl of mitochondrial suspension containing 7.5 × 10⁶ mitochondria/ml of respiration buffer) in recipient groups. Twenty-four hours post-operation, LDH and cTn-I levels, mitochondrial functional endpoints, expression of mitochondrial biogenesis (SIRT-1 and PGC-1α) and fission/fusion (Drp1/Mfn1 and Mfn2) genes, and inflammatory cytokines (TNF-α, IL-1β, and IL-6) levels were evaluated. Survival was tested over 72 h post-operation.

RESULTS

Mitotherapy significantly improved 72-hours survival (P < .05) and decreased LDH and cTn-I levels (P < .01). It also restored mitochondrial function and expression of mitochondrial biogenesis and fusion genes, and decreased the expression of mitochondrial fission gene and the levels of inflammatory cytokines (P < .05 to P < .01). Mitotherapy with repetitive injections at 1 and 7 h post-CLP provided noticeable mitoprotection in comparison with the group receiving mitotherapy at single injection.

CONCLUSION

Mitotherapy improved mitochondrial function, biogenesis, and dynamic associated with SIRT-1/PGC-1α network and suppressed inflammatory response in CLP-induced sepsis model, therefore, offers a promising strategy to overcome life-threatening sepsis challenge.

Metabolic Reprogramming and Its Regulatory Mechanism in Sepsis-Mediated Inflammation

Sepsis is a systemic inflammatory disease caused by an infection that can lead to multiple organ failure. Sepsis alters energy metabolism, leading to metabolic reprogramming of immune cells, which consequently disrupts innate and adaptive immune responses, triggering hyperinflammation and immunosuppression. This review summarizes metabolic reprogramming and its regulatory mechanism in sepsis-induced hyperinflammation and immunosuppression, highlights the significance and intricacies of immune cell metabolic reprogramming, and emphasizes the pivotal role of mitochondria in metabolic regulation and treatment of sepsis. This review provides an up-to-date overview of the relevant literature to inform future research directions in understanding the regulation of sepsis immunometabolism. Metabolic reprogramming has great promise as a new target for sepsis treatment in the future.

Exploring Dysregulated Ferroptosis-Related Genes in Septic Myocardial Injury Based on Human Heart Transcriptomes: Evidence and New Insights

Introduction

Sepsis is currently a common condition in emergency and intensive care units, and is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Cardiac dysfunction caused by septic myocardial injury (SMI) is associated with adverse prognosis and has significant economic and human costs. The pathophysiological mechanisms underlying SMI have long been a subject of interest. Recent studies have identified ferroptosis, a form of programmed cell death associated with iron accumulation and lipid peroxidation, as a pathological factor in the development of SMI. However, the current understanding of how ferroptosis functions and regulates in SMI remains limited, particularly in the absence of direct evidence from human heart.

Methods

We performed a sequential comprehensive bioinformatics analysis of human sepsis cardiac transcriptome data obtained through the GEO database. The lipopolysaccharide-induced mouse SMI model was used to validate the ferroptosis features and transcriptional expression of key genes.

Results

We identified widespread dysregulation of ferroptosis-related genes (FRGs) in SMI based on the human septic heart transcriptomes, deeply explored the underlying biological mechanisms and crosstalks, followed by the identification of key functional modules and hub genes through the construction of protein-protein interaction network. Eight key FRGs that regulate ferroptosis in SMI, including HIF1A, MAPK3, NOX4, PPARA, PTEN, RELA, STAT3 and TP53, were identified, as well as the ferroptosis features. All the key FRGs showed excellent diagnostic capability for SMI, part of them was associated with the prognosis of sepsis patients and the immune infiltration in the septic hearts, and potential ferroptosis-modulating drugs for SMI were predicted based on key FRGs.

Conclusion

This study provides human septic heart transcriptome-based evidence and brings new insights into the role of ferroptosis in SMI, which is significant for expanding the understanding of the pathobiological mechanisms of SMI and exploring promising diagnostic and therapeutic targets for SMI.

Hydrogen sulfide plays an important role by regulating endoplasmic reticulum stress in myocardial diseases

Endoplasmic reticulum (ER) is an important organelle for protein translation, folding and translocation, as well as the post-translational modification and assembly of newly synthesized secreted proteins. When the excessive accumulation of misfolded and/or unfolded proteins exceeds the processing capacity of ER, ER stress is triggered. The integrated intracellular signal cascade, namely the unfolded protein response, is induced to avoid ER stress. ER stress is involved in many pathological and physiological processes including myocardial diseases. For a long time, hydrogen sulfide (H₂S) has been considered as a toxic gas with the smell of rotten eggs. However, more and more evidences indicate that H₂S is an important gas signal molecule after nitric oxide and carbon monoxide, and regulates a variety of physiological and pathological processes in mammals. In recent years, increasing studies have focused on the regulatory effects of H₂S on ER stress in myocardial diseases, however, the mechanism is not very clear. Therefore, this review focuses on the role of H₂S regulation of ER stress in myocardial diseases, and deeply analyzes the relevant mechanisms so as to lay the foundation for the future researches.

Jujuboside A attenuates sepsis-induced cardiomyopathy by inhibiting inflammation and regulating autophagy

BACKGROUND

Jujuboside A (JuA), as a main effective component of Jujubogenin, has long been known as a sedative-hypnotic drug. The aim of the current study was to investigate the potential effect of JuA on sepsis-induced cardiomyopathy (SIC) induced by lipopolysaccharide (LPS).

METHOD

Wide type C57BL/6 mice and neonatal rat cardiomyocytes (NRCMs) were exposed to LPS to establish myocardial toxicity models. Cardiac function of septic mice was detected by echocardiography. Moreover, the survival rate was calculated for 7 days. ELISA assays were used to analyze inflammatory factors in serum. Furthermore, western blotting, flow cytometry and TUNEL staining were performed to assess cell apoptosis and transmission electron microscopy detect the number of autophagosomes in myocardium. Finally, the expression of proteins related to pyroptosis, autophagy and oxidative stress was analyzed by western blotting and immunohistochemistry staining.

RESULTS

Results showed that JuA pretreatment significantly improved the survival rate and cardiac function, and suppressed systemic inflammatory response in septic mice. Further study revealed that JuA could decrease cell apoptosis and pyroptosis; instead, it strengthened autophagy in SIC. Moreover, JuA also significantly decreased oxidative stress and nitrodative stress, as evidenced by suppressing the superoxide production and downregulating iNOS and gp91 expression in vivo. In addition, the autophagy inhibitor 3-MA significantly abolished the effect of JuA on autophagic activity in SIC.

CONCLUSION

In conclusion, the findings indicated that JuA attenuates cardiac function via blocking inflammasome-mediated apoptosis and pyroptosis, at the same time by enhancing autophagy in SIC, heralding JuA as a potential therapy for sepsis.

Central α7 and α4β2 nicotinic acetylcholine receptors offset arterial baroreceptor dysfunction in endotoxic rats

Cardiac autonomic neuropathy is a prominent feature of endotoxemia. Given the defensive role of the cholinergic pathway in inflammation, we assessed the roles of central homomeric α7 and heteromeric α4β2 nAChRs in arterial baroreceptor dysfunction caused by endotoxemia in rats. Endotoxemia was induced by i.v. administration of lipopolysaccharides (LPS, 10 mg/kg), and baroreflex activity was measured by the vasoactive method, which assesses reflex chronotropic responses to increments (phenylephrine, PE) or decrements (sodium nitroprusside, SNP) in blood pressure. Shifts caused by LPS in PE/SNP baroreflex curves and associated decreases in baroreflex sensitivity (BRS) were dose-dependently reversed by nicotine (25-100 μg/kg, i.v.). The nicotine effect disappeared after intracisternal administration of methyllycaconitine (MLA) or dihydro-β-erythroidine (DHβE), selective blockers of α7 and α4β2 receptors, respectively. The advantageous effect of nicotine on BRSPE was replicated in rats treated with PHA-543613 (α7-nAChR agonist) or 5-iodo-A-85380 (5IA, α4β2-nAChRs agonist) in dose-dependent fashions. Conversely, the depressed BRSSNP of endotoxic rats was improved after combined, but not individual, treatments with PHA and 5IA. Central α7 and α4β2 nAChR activation underlies the nicotine counteraction of arterial baroreflex dysfunction induced by endotoxemia. Moreover, the contribution of these receptors depends on the nature of the reflex chronotropic response (bradycardia vs. tachycardia).

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.

Glutathione deficiency in the pathogenesis of SARS-CoV-2 infection and its effects upon the host immune response in severe COVID-19 disease

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 19 (COVID-19) has numerous risk factors leading to severe disease with high mortality rate. Oxidative stress with excessive production of reactive oxygen species (ROS) that lower glutathione (GSH) levels seems to be a common pathway associated with the high COVID-19 mortality. GSH is a unique small but powerful molecule paramount for life. It sustains adequate redox cell signaling since a physiologic level of oxidative stress is fundamental for controlling life processes via redox signaling, but excessive oxidation causes cell and tissue damage. The water-soluble GSH tripeptide (γ-L-glutamyl-L-cysteinyl-glycine) is present in the cytoplasm of all cells. GSH is at 1–10 mM concentrations in all mammalian tissues (highest concentration in liver) as the most abundant non-protein thiol that protects against excessive oxidative stress. Oxidative stress also activates the Kelch-like ECH-associated protein 1 (Keap1)-Nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) redox regulator pathway, releasing Nrf2 to regulate the expression of genes that control antioxidant, inflammatory and immune system responses, facilitating GSH activity. GSH exists in the thiol-reduced and disulfide-oxidized (GSSG) forms. Reduced GSH is the prevailing form accounting for >98% of total GSH. The concentrations of GSH and GSSG and their molar ratio are indicators of the functionality of the cell and its alteration is related to various human pathological processes including COVID-19. Oxidative stress plays a prominent role in SARS-CoV-2 infection following recognition of the viral S-protein by angiotensin converting enzyme-2 receptor and pattern recognition receptors like toll-like receptors 2 and 4, and activation of transcription factors like nuclear factor kappa B, that subsequently activate nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) expression succeeded by ROS production. GSH depletion may have a fundamental role in COVID-19 pathophysiology, host immune response and disease severity and mortality. Therapies enhancing GSH could become a cornerstone to reduce severity and fatal outcomes of COVID-19 disease and increasing GSH levels may prevent and subdue the disease. The life value of GSH makes for a paramount research field in biology and medicine and may be key against SARS-CoV-2 infection and COVID-19 disease.

Metabolic reprogramming consequences of sepsis: adaptations and contradictions

During sepsis, the importance of alterations in cell metabolism is underappreciated. The cellular metabolism, which has a variable metabolic profile in different cells and disease stages, is largely responsible for the immune imbalance and organ failure associated with sepsis. Metabolic reprogramming, in which glycolysis replaces OXPHOS as the main energy-producing pathway, is both a requirement for immune cell activation and a cause of immunosuppression. Meanwhile, the metabolites produced by OXPHOS and glycolysis can act as signaling molecules to control the immune response during sepsis. Sepsis-induced "energy shortage" leads to stagnated cell function and even organ dysfunction. Metabolic reprogramming can alleviate the energy crisis to some extent, enhance host tolerance to maintain cell survival functions, and ultimately increase the adaptation of cells during sepsis. However, a switch from glycolysis to OXPHOS is essential for restoring cell function. This review summarized the crosstalk between metabolic reprogramming and immune cell activity as well as organ function during sepsis, discussed the benefits and drawbacks of metabolic reprogramming to show the contradictions of metabolic reprogramming during sepsis, and assessed the feasibility of treating sepsis through targeted metabolism. Using metabolic reprogramming to achieve metabolic homeostasis could be a viable therapy option for sepsis.

LncRNA MALAT1 Regulates USP22 Expression Through EZH2-Mediated H3K27me3 Modification to Accentuate Sepsis-Induced Myocardial Dysfunction

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), a long non-coding RNA (lncRNA), has been confirmed to recruit enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) to regulate cardiomyocyte apoptosis in diabetic cardiomyopathy. However, whether the similar regulatory axis exists in sepsis-induced myocardial dysfunction (SIMD) has not been clearly established. The current study sought to define the mechanism governing MALAT1-mediated EZH2 in SIMD. MALAT1 was significantly upregulated in lipopolysaccharide-induced cardiomyocytes. Depletion of MALAT1 by caudal vein injection of small interfering RNA targeting MALAT1 alleviated myocardial injury in SIMD rats, restored cardiac function, reduced oxidative stress production and fibrosis, and inhibited inflammatory factors and apoptosis in myocardial tissues. Moreover, MALAT1 bound to EZH2 and promoted EZH2 activity in the nucleus of cardiomyocytes. EZH2 repressed ubiquitin-specific peptidase 22 (USP22) expression through H3K27me3 modification. EZH2 elevation aggravated the cardiac injury in SIMD rats, while USP22 upregulation inhibited the effect of EZH2, which reduced the cardiac injury in SIMD rats. Taken together, MALAT1 decreased USP22 expression by interacting with EZH2, thereby worsening SIMD, highlighting an attractive therapeutic strategy for SIMD.

An Overview on Mitochondrial-Based Therapies in Sepsis-Related Myocardial Dysfunction: Mitochondrial Transplantation as a Promising Approach

Sepsis is defined as a life-threatening organ failure due to dysregulated host response to infection. Despite current advances in our knowledge about sepsis, it is still considered as a major global health challenge. Myocardial dysfunction is a well-defined manifestation of sepsis which is related to worse outcomes in septic patients. Given that the heart is a mitochondria-rich organ and the normal function of mitochondria is essential for successful modulation of septic response, the contribution of mitochondrial damage in sepsis-related myocardial dysfunction has attracted the attention of many scientists. It is widely accepted that mitochondrial damage is involved in sepsis-related myocardial dysfunction; however, effective and potential treatment modalities in clinical setting are still lacking. Mitochondrial-based therapies are potential approaches in sepsis treatment. Although various therapeutic strategies have been used for mitochondrial function improvement, their effects are limited when mitochondria undergo irreversible alterations under septic challenge. Therefore, application of more effective approaches such as mitochondrial transplantation has been suggested. This review highlights the crucial role of mitochondrial damage in sepsis-related myocardial dysfunction, then provides an overview on mitochondrial-based therapies and current approaches to mitochondrial transplantation as a novel strategy, and proposes future directions for more researches in this field.

Troponin I Cutoff for Non-ST-Segment Elevation Myocardial Infarction in Sepsis

The diagnostic value and optimal cutoff level of cardiac troponin I in patients with sepsis have not been studied. In this single hospital retrospective study, we assessed the optimal cutoff value of troponin I for diagnosing non-ST-segment elevation myocardial infarction (NSTEMI) with type 1 myocardial infarction (MI) in patients with sepsis who had undergone a percutaneous coronary intervention from 2009 to 2019. In total, 5,341 patients (excluding patients with chronic kidney disease) were included, of whom 277 had sepsis or septic shock. Of the 123 patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) and sepsis, 77 (62.6%) were diagnosed with NSTEMI with type 1 MI. The receiver-operating characteristic curve showed an area under the curve (AUC) of 0.705 for diagnosis of NSTEMI with type 1 MI with a troponin I cutoff of >300 ng/L (sensitivity: 68.4%, specificity: 70.2%, Youden index: 0.386). Multiple linear regression showed no significant predictors of NSTEMI with type 1 MI. Troponin level and the Global Registry of Acute Coronary Events (GRACE) scores were correlated (R² = 0.0625, p = 0.032) and showed comparable predictive value for 6-month mortality (AUC: 0.637 and 0.611, respectively, p = 0.7651). The optimal troponin I cutoff to effectively diagnose NSTEMI with type 1 MI in patients with sepsis was 300 ng/L.

Regulation of Oxidative Phosphorylation of Liver Mitochondria in Sepsis

The link between liver dysfunction and decreased mitochondrial oxidative phosphorylation in sepsis has been clearly established in experimental models. Energy transduction is plastic: the efficiency of mitochondrial coupling collapses in the early stage of sepsis but is expected to increase during the recovery phases of sepsis. Among the mechanisms regulating the coupling efficiency of hepatic mitochondria, the slipping reactions at the cytochrome oxidase and ATP synthase seem to be a determining element, whereas other regulatory mechanisms such as those involving proton leakage across the mitochondrial membrane have not yet been formally proven in the context of sepsis. If the dysfunction of hepatic mitochondria is related to impaired cytochrome c oxidase and ATP synthase functions, we need to consider therapeutic avenues to restore their activities for recovery from sepsis. In this review, we discussed previous findings regarding the regulatory mechanism involved in changes in the oxidative phosphorylation of liver mitochondria in sepsis, and propose therapeutic avenues to improve the functions of cytochrome c oxidase and ATP synthase in sepsis.

Pterostilbene Interferes With Lipopolysaccharide-Induced Myocardial Injury Through Oxidative Stress and Inflammasome Pathways

Myocardial contractile dysfunction caused by sepsis is a serious threat to human health, and its pathogenesis is not completely clear. It is generally believed that excessive inflammation and oxidative stress are the main causes of myocardial damage caused by sepsis. Pterostilbene (PTS) has a variety of biological activities, including anti-oxidant, anti-inflammatory, and anti-aging. Whether PTS protect myocardial function in rats with sepsis through anti-inflammatory and anti-oxidant effects has not been reported. In this study, we investigated the role of PTS in septic mice induced by lipopolysaccharide (LPS). Mice were injected intraperitoneally with LPS (20 mg/kg) to simulate sepsis. Use Echocardiography, Masson, DHE, H&amp;E, IHC, IF and other experimental methods to explore the effects of PTS on LPS. The results showed that PTS was indicated to significantly increase the cardiac function of mice with sepsis. PTS treatment also reduced the mRNA expression of IL-1α, IL-6, MCP-1, and IL-1β and the protein expression of NLRP3 in vivo and in vitro, and inhibited the migration of inflammatory cells. PTS treatment also reduced the mRNA expression of collagen I, collagen III and α-SMA, and inhibited fibrosis. PTS treatment reduced the mRNA expression of NOX1, NOX2, and NOX4 and inhibited DHE levels in vivo and in vitro. In summary, our data indicated that PTS played a crucial role in LPS-induced myocardial injured and might be a key target for the prevention and treatment of sepsis-induced myocardial dysfunction.

Diagnostic significance of heart-type fatty acid-binding protein as a potential biomarker to predict the mortality rate of patients with sepsis: a systematic review and meta-analysis

BACKGROUND

Some studies have found that heart-type fatty acid-binding protein (H-FABP) is related to the prognosis of patients with sepsis. This study aimed to explore whether H-FABP could predict the 28-day mortality in patients with sepsis.

METHODS

Seven databases were searched, and the studies were screened based on the inclusion and exclusion criteria to assess the quality. The pooled sensitivity (SEN), specificity (SPE) positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and the area under the curve (AUC) of the summary receiver operating characteristic (SROC) curve were calculated along with the 95% confidence interval (CI) values. Deeks' funnel plot was used to ascertain any publication bias. Meta-regression analysis was performed to explore the possible sources of heterogeneity.

RESULTS

Seven studies were assessed that included 822 patients with sepsis. The pooled SEN was 0.76 (95% CI, 0.71-0.81), SPE was 0.66 (95% CI, 0.61-0.70), PLR was 2.21 (95% CI, 1.73-2.83), NLR was 0.36 (95% CI, 0.29-0.54), DOR was 6.23 (95% CI, 4.27-9.11) and the pooled AUC was 0.8137. There was no publication bias. Race, literature language, sampling time, threshold division and threshold effect were not the causes for the large heterogeneity.

CONCLUSIONS

This meta-analysis suggests that H-FABP has high accuracy in predicting the 28-day mortality rate of patients with sepsis.

The regulatory mechanism between lysosomes and mitochondria in the aetiology of cardiovascular diseases

Coordinated action among various organelles maintains cellular functions. For instance, mitochondria and lysosomes are the main organelles contributing to cellular metabolism and provide energy for cardiomyocyte contraction. They also provide essential signalling platforms in the cell that regulate many key processes such as autophagy, apoptosis, oxidative stress, inflammation and cell death. Often, abnormalities in mitochondrial or lysosomal structures and functions bring about cardiovascular diseases (CVDs). Although the communication between mitochondria and lysosomes throughout the cardiovascular system is intensely studied, the regulatory mechanisms have not been completely understood. Thus, we summarize the most recent studies related to mitochondria and lysosomes' role in CVDs and their potential connections and communications under cardiac pathophysiological conditions. Further, we discuss limitations and future perspectives regarding diagnosis, therapeutic strategies and drug discovery in CVDs.

IL-6/STAT3 Signaling Promotes Cardiac Dysfunction by Upregulating FUNDC1-Dependent Mitochondria-Associated Endoplasmic Reticulum Membranes Formation in Sepsis Mice

Aims

Cytokine storm is closely related to the initiation and progression of sepsis, and the level of IL-6 is positively correlated with mortality and organ dysfunction. Sepsis-induced myocardial dysfunction (SIMD) is one of the major complications. However, the role of the IL-6/STAT3 signaling in the SIMD remains unclear.

Methods and Results

Septic mice were induced by intraperitoneal injection of LPS (10 mg/kg). Echocardiography, cytokines detection, and histologic examination showed that sepsis mice developed cardiac systolic and diastolic dysfunction, increase of inflammatory cytokines in serum, activated STAT3 and TLR4/NFκB pathway in heart, and raised myocardial apoptosis, which were attenuated by IL-6/STAT3 inhibitor, Bazedoxifene. In vitro, we found that LPS decreased cell viability in a concentration-dependent manner and activated STAT3. Western blot and immunofluorescence results indicated that STAT3 phosphorylation induced by LPS was inhibited by Bazedoxifene. Bazedoxifene also suppressed LPS-induced IL-6 transcription. sIL-6R caused LPS-induced p-STAT3 firstly decreased and then significantly increased. More importantly, we found STAT3-knockdown suppressed LPS-induced expression of FUNDC1, a protein located in mitochondria-associated endoplasmic reticulum membranes (MAMs). Overexpression of STAT3 led to an increase in FUNDC1 expression. Dual-luciferase reporter assay was used to confirm that STAT3 was a potential transcription factor for FUNDC1. Moreover, we showed that LPS increased MAMs formation and intracellular Ca2+ levels, enhanced the expression of Cav1.2 and RyR2, decreased mitochondrial membrane potential and intracellular ATP levels, and promoted mitochondrial fragmentation, the expression of mitophagy proteins and ROS production in H9c2 cells, which were reversed by knockdown of FUNDC1 and IL-6/STAT3 inhibitor including Bazedoxifene and Stattic.

Conclusions

IL-6/STAT3 pathway plays a key role in LPS-induced myocardial dysfunction, through regulating the FUNDC1-associated MAMs formation and interfering the function of ER and mitochondria. IL-6/STAT3/FUNDC1 signaling could be a new therapeutic target for SIMD.

Novel Insights Into the Potential Mechanisms of N6-Methyladenosine RNA Modification on Sepsis-Induced Cardiovascular Dysfunction: An Update Summary on Direct and Indirect Evidences

Sepsis is a life-threatening organ dysfunction caused by a host’s dysfunctional response to infection. As is known to all, septic heart disease occurs because pathogens invading the blood stimulate the activation of endothelial cells, causing a large number of white blood cells to accumulate and trigger an immune response. However, in severe sepsis, the hematopoietic system is inhibited, and there will also be a decline in white blood cells, at which time the autoimmune system will also be suppressed. During the immune response, a large number of inflammatory factors are released into cells to participate in the inflammatory process, which ultimately damages cardiac myocytes and leads to impaired cardiac function. N6-methyladenosine (m6A) is a common RNA modification in mRNA and non-coding RNA that affects RNA splicing, translation, stability, and epigenetic effects of some non-coding RNAs. A large number of emerging evidences demonstrated m6A modification had been involved in multiple biological processes, especially for sepsis and immune disorders. Unfortunately, there are limited results provided to analyze the association between m6A modification and sepsis-induced cardiovascular dysfunction (SICD). In this review, we firstly summarized current evidences on how m6A mediates the pathophysiological process in cardiac development and cardiomyopathy to emphasize the importance of RNA methylation in maintaining heart biogenesis and homeostasis. Then, we clarified the participants of m6A modification in extended inflammatory responses and immune system activation, which are the dominant and initial changes secondary to sepsis attack. After that, we deeply analyzed the top causes of SICD and identified the activation of inflammatory cytokines, endothelial cell dysfunction, and mitochondrial failure. Thus, the highlight of this review is that we systematically collected all the related potential mechanisms between m6A modification and SICD causes. Although there is lack of direct evidences on SICD, indirect evidences had been demonstrated case by case on every particular molecular mechanism and signal transduction, which require further explorations into the potential links among the listed mechanisms. This provides novel insights into the understanding of SICD.

Cardiac Metabolism in Sepsis

The mechanism of sepsis-induced cardiac dysfunction is believed to be different from that of myocardial ischemia. In sepsis, chemical mediators, such as endotoxins, cytokines, and nitric oxide, cause metabolic abnormalities, mitochondrial dysfunction, and downregulation of β-adrenergic receptors. These factors inhibit the production of ATP, essential for myocardial energy metabolism, resulting in cardiac dysfunction. This review focuses on the metabolic changes in sepsis, particularly in the heart. In addition to managing inflammation, interventions focusing on metabolism may be a new therapeutic strategy for cardiac dysfunction due to sepsis.

Mitochondrial gene mutations in pediatric septic shock

BACKGROUND

There has been a growing interest in the association between mitochondrial dysfunction and sepsis. However, most studies have focused on mitochondrial structural damage, functional aspects, or the clinical phenotypes in sepsis. The purpose of this study was to evaluate mitochondrial DNA (mtDNA) gene mutations in critically ill pediatric patients with septic shock.

METHOD

Thirteen patients with severe sepsis or septic shock admitted to the pediatric intensive care unit (PICU) of a tertiary children's hospital were enrolled in this prospective observational study. Clinical data from electronic medical records were obtained. Whole-blood samples were collected within 24 h of PICU admission to perform PBMC isolation, mtDNA extraction, and mtDNA sequencing using next-generation sequencing.

RESULTS

mtDNA sequencing revealed mutations in 9 of the 13 patients, presenting 27 point mutations overall, with 15 (55.6%) located in the locus related to adenosine triphosphate production and superoxide metabolism, including electron transport.

CONCLUSION

In this pilot study, significant numbers of mtDNA point mutations were detected in critically ill pediatric patients with septic shock. These mutations could provide promising evidence for mitochondrial dysfunction in sepsis and a basis for further large-scale studies.

IMPACT

This study is the first to examine mitochondrial DNA mutations in pediatric patients with septic shock using next-generation sequencing. A high frequency of mitochondrial DNA mutations was detected in these patients indicating an association with septic shock. This pilot study may provide a potential explanation for the association between mitochondrial dysfunction and septic shock on a genetic basis.

Predictive value and regulatory mechanism of serum miR-499a-5p on myocardial dysfunction in sepsis

Background

This study sought to investigate the predictive value and regulatory mechanism of serum miR-499a-5p in sepsis-induced myocardial dysfunction (SIMD).

Methods

A total of 60 patients with sepsis and 60 healthy volunteers were enrolled in this study. The serum levels of miRNAs (miR-451, miR-378 and miR-499a-5p) were detected. Receiver operating characteristic curve and logistic regression analysis were used to evaluate the diagnostic and prognostic value of miR-499a-5p in SIMD patients. AC16 cells were used to establish SIMD model in vitro using lipopolysaccharide (LPS). An analysis was conducted for miR-499a-5p expression, cell viability, and the concentration of creatine kinase-MB isoform (CK-MB), brain natriuretic peptide (BNP), superoxide dismutase (SOD) and cytochrome C oxidase IV (COX IV). The downstream target of miR-499a-5p was verified.

Results

Our results revealed a poor expression of miR-499a-5p in the serum of SIMD patients, while no significant difference was evident for miR-451 and miR-378. The level of miR-499a-5p in the survival group was higher than the non-survival group. miR-499a-5p elicited good diagnostic and prognostic value for SIMD. Our findings revealed that miR-499a-5p was decreased significantly in LPS-treated cardiomyocytes. After overexpression of miR-499a-5p, the cell viability increased, and the concentrations of CK-MB and BNP were decreased, while the concentrations of SOD and COX IV were increased. EIF4E was validated as the target of miR-499a-5p. After overexpression of EIF4E, the cell viability was decreased and the concentrations of CK-MB and BNP were increased while the concentrations of SOD and COX IV were decreased.

Conclusion

The level of miR-499a-5p is weak in SIMD patients. miR-499a-5p has a good diagnostic and prognostic value for SIMD by inhibiting EIF4E transcription.

Immunometabolic signatures predict risk of progression to sepsis in COVID-19

Viral sepsis has been proposed as an accurate term to describe all multisystemic dysregulations and clinical findings in severe and critically ill COVID-19 patients. The adoption of this term may help the implementation of more accurate strategies of early diagnosis, prognosis, and in-hospital treatment. We accurately quantified 110 metabolites using targeted metabolomics, and 13 cytokines/chemokines in plasma samples of 121 COVID-19 patients with different levels of severity, and 37 non-COVID-19 individuals. Analyses revealed an integrated host-dependent dysregulation of inflammatory cytokines, neutrophil activation chemokines, glycolysis, mitochondrial metabolism, amino acid metabolism, polyamine synthesis, and lipid metabolism typical of sepsis processes distinctive of a mild disease. Dysregulated metabolites and cytokines/chemokines showed differential correlation patterns in mild and critically ill patients, indicating a crosstalk between metabolism and hyperinflammation. Using multivariate analysis, powerful models for diagnosis and prognosis of COVID-19 induced sepsis were generated, as well as for mortality prediction among septic patients. A metabolite panel made of kynurenine/tryptophan ratio, IL-6, LysoPC a C18:2, and phenylalanine discriminated non-COVID-19 from sepsis patients with an area under the curve (AUC (95%CI)) of 0.991 (0.986-0.995), with sensitivity of 0.978 (0.963-0.992) and specificity of 0.920 (0.890-0.949). The panel that included C10:2, IL-6, NLR, and C5 discriminated mild patients from sepsis patients with an AUC (95%CI) of 0.965 (0.952-0.977), with sensitivity of 0.993(0.984-1.000) and specificity of 0.851 (0.815-0.887). The panel with citric acid, LysoPC a C28:1, neutrophil-lymphocyte ratio (NLR) and kynurenine/tryptophan ratio discriminated severe patients from sepsis patients with an AUC (95%CI) of 0.829 (0.800-0.858), with sensitivity of 0.738 (0.695-0.781) and specificity of 0.781 (0.735-0.827). Septic patients who survived were different from those that did not survive with a model consisting of hippuric acid, along with the presence of Type II diabetes, with an AUC (95%CI) of 0.831 (0.788-0.874), with sensitivity of 0.765 (0.697-0.832) and specificity of 0.817 (0.770-0.865).

Lipocalin 10 as a New Prognostic Biomarker in Sepsis-Induced Myocardial Dysfunction and Mortality: A Pilot Study

Introduction

Sepsis-induced myocardial dysfunction (SIMD) is the most common complications of sepsis and septic shock with extremely high incidence and mortality. Lipocalin 10 (Lcn10) has recently been identified as a potential biomarker for heart failure, yet its relation to sepsis has not been investigated. The purpose of this study was to explore whether circulating Lcn10 could be used as a prognostic tool in patients with SIMD.

Methods

In this single-center observational pilot study, seventy-five sepsis patients were enrolled after sepsis diagnosis or ICU admission (45.3% female, median age 60 years), and 35 patients (46.7%) developed myocardial dysfunction. Serum Lcn10 levels of septic patients were measured using the enzyme-linked immunosorbent assay (ELISA) at the time of admission. Other biomarkers of cardiac function and Lcn10 concentration were compared between SIMD and non-SIMD groups.

Results

We observed that the median Lcn10 levels were 2.780 ng/mL in patients with SIMD and 2.075 ng/mL in patients without SIMD (P < 0.05). The area under the receiver operating characteristic (ROC) curve for the diagnosis of SIMD was 0.797 (P < 0.05). In addition, elevated serum Lcn10 levels at the time of admission were positively associated with 28-day mortality in septic patients.

Conclusions

Our study indicates that circulating Lcn10 levels may serve as a novel biomarker for the diagnosis and prognosis of myocardial dysfunction induced by sepsis. An additional large multicenter study may be warranted to confirm the findings of this study.

Regulatory role of the TLR4/JNK signaling pathway in sepsis‑induced myocardial dysfunction

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection, and is a leading cause of mortality worldwide. Myocardial dysfunction is associated with poor prognosis in patients with sepsis and contributes to a high risk of mortality. However, the pathophysiological mechanisms underlying sepsis-induced myocardial dysfunction are not completely understood. The aim of the present study was to investigate the role of toll-like receptor 4 (TLR4)/c-Jun N-terminal kinase (JNK) signaling in pro-inflammatory cytokine expression and cardiac dysfunction during lipopolysaccharide (LPS)-induced sepsis in mice. C57BL/6 mice were pretreated with TAK-242 or saline for 1 h and then subjected to LPS (12 mg/kg, intraperitoneal) treatment. Cardiac function was assessed using an echocardiogram. The morphological changes of the myocardium were examined by hematoxylin and eosin staining and transmission electron microscopy. The serum protein levels of cardiac troponin I (cTnI) and tumor necrosis factor-α (TNF-α) were determined by an enzyme-linked immunosorbent assay (ELISA). The TLR4 and JNK mRNA levels were analyzed via reverse transcription-quantitative PCR. TLR4, JNK and phosphorylated-JNK protein levels were measured by western blotting. In response to LPS, the activation of TLR4 and JNK in the myocardium was upregulated. There were significant increases in the serum levels of TNF-α and cTnI, as well as histopathological changes in the myocardium and suppressed cardiac function, following LPS stimulation. Inhibition of TLR4 activation using TAK-242 led to a decrease in the activation of JNK and reduced the protein expression of TNF-α in plasma, and alleviated histological myocardial injury and improved cardiac function during sepsis in mice. The present data suggested that the TLR4/JNK signaling pathway played a critical role in regulating the production of pro-inflammatory cytokines and myocardial dysfunction induced by LPS.

High serum nitrates levels in non-survivor COVID-19 patients

OBJECTIVE

Higher blood nitrate and nitrite levels have been found in coronavirus disease 2019 (COVID-19) patients than in healthy subjects. The present study explores the potential association between serum nitrate levels and mortality in COVID-19 patients.

DESIGN

A prospective observation study was carried out.

SETTING

Eight Intensive Care Units (ICUs) from 6 hospitals in the Canary Islands (Spain).

PATIENTS

COVID-19 patients admitted to the ICU.

INTERVENTIONS

Determination of serum nitrate levels at ICU admission.

MAIN VARIABLE OF INTEREST

Mortality at 30 days.

RESULTS

Non-surviving (n=11) compared to surviving patients (n=42) showed higher APACHE-II (p<0.001) and SOFA scores (p=0.004), and higher serum nitrate levels (p=0.001). Logistic regression analyses showed serum nitrate levels to be associated to 30-day mortality after controlling for SOFA (OR=1.021; 95%CI=1.006-1.036; p=0.01) or APACHE-II (OR=1.023; 95%CI=1.006-1.041; p=0.01). There were no differences in the area under the curve (AUC) for mortality prediction by serum nitrate levels (AUC=83%; 95%CI=73-92%; p<0.001), APACHE II (AUC=85%; 95%CI=75-96%; p<0.001) and SOFA (AUC=78%; 95%CI=63-92%; p=0.005) based on the DeLong method. The Kaplan-Meier analysis found patients with serum nitrates levels>68.4μmol/l to have a higher mortality rate (hazard ratio=138.8; 95%CI=22.3-863.9; p<0.001).

CONCLUSIONS

The main novel finding was the association between serum nitrate levels and mortality in COVID-19 patients controlling for the SOFA or APACHE-II scores, though larger studies are needed to confirm this observation.

Haemodynamic monitoring and management in COVID-19 intensive care patients: an International survey

PURPOSE

To survey haemodynamic monitoring and management practices in intensive care patients with the coronavirus disease 2019 (COVID-19).

METHODS

A questionnaire was shared on social networks or via email by the authors and by Anaesthesia and/or Critical Care societies from France, Switzerland, Belgium, Brazil, and Portugal. Intensivists and anaesthetists involved in COVID-19 ICU care were invited to answer 14 questions about haemodynamic monitoring and management.

RESULTS

Globally, 1000 questionnaires were available for analysis. Responses came mainly from Europe (n = 460) and America (n = 434). According to a majority of respondents, COVID-19 ICU patients frequently or very frequently received continuous vasopressor support (56%) and had an echocardiography performed (54%). Echocardiography revealed a normal cardiac function, a hyperdynamic state (43%), hypovolaemia (22%), a left ventricular dysfunction (21%) and a right ventricular dilation (20%). Fluid responsiveness was frequently assessed (84%), mainly using echo (62%), and cardiac output was measured in 69%, mostly with echo as well (53%). Venous oxygen saturation was frequently measured (79%), mostly from a CVC blood sample (94%). Tissue perfusion was assessed biologically (93%) and clinically (63%). Pulmonary oedema was detected and quantified mainly using echo (67%) and chest X-ray (61%).

CONCLUSION

Our survey confirms that vasopressor support is not uncommon in COVID-19 ICU patients and suggests that different haemodynamic phenotypes may be observed. Ultrasounds were used by many respondents, to assess cardiac function but also to predict fluid responsiveness and quantify pulmonary oedema. Although we observed regional differences, current international guidelines were followed by most respondents.

Acute myocardial dysfunction in lupus: outcomes in Asian Indians

BACKGROUND

Acute myocardial dysfunction is an uncommon but potentially fatal complication in systemic lupus erythematosus (SLE). We describe the outcome in a small series of Asian Indian patients and examine associated factors.

METHODS

SLE patients who fulfilled the 2012 SLICC criteria and developed new-onset myocardial dysfunction were included in this retrospective case series. Acute myocardial dysfunction was defined as global hypokinesia and left ventricular ejection fraction (LVEF)<50% on echocardiography (with or without symptoms) in patients with SLE. Survival was assessed using Kaplan-Meier survival analysis and Cox regression.

RESULTS

This study included 37 patients with mean age 28.2 ± 11.2 years and median (range) LVEF of 35% (18-48%) at presentation. A majority had active disease, with SLEDAI-2k ≥ 5 in 26 (of 28). All patients received oral corticosteroids and a majority received additional immunosuppression, including pulse methylprednisolone in 28 and cyclophosphamide in 27. Nine patients died during hospitalisation (25%), a majority due to infections. Death was significantly associated with elevated procalcitonin at presentation (p = 0.05), elevated white cell count (p = 0.02) and low complement C3 (p = 0.03). In those who survived, long-term outcomes were good, with complete myocardial recovery in 14 (64%). A higher ejection fraction at presentation was associated with complete recovery.

CONCLUSIONS

In this small series of patients of SLE with acute myocardial dysfunction, we report a significant in-hospital mortality due to infections. Many of the patients who died had elevated procalcitonin at presentation. A diligent search for infection seems prudent in lupus patients who present with acute myocardial dysfunction. Key Points • In patients of SLE with acute myocardial dysfunction who were treated with immunosuppression, there was significant short-term mortality due to infections. • This mortality was associated with elevated procalcitonin at baseline and may suggest some of them had pre-existing hidden sepsis. • A prudent search for infections in these patients before immunosuppression may help to decrease short-term mortality.