Evaluation of sepsis induced cardiac dysfunction as a predictor of mortality

Effect of ultrashort-acting β-blockers on 28-day mortality in patients with sepsis with persistent tachycardia despite initial resuscitation: a meta-analysis of randomized controlled trials and trial sequential analysis

Purpose

This meta-analysis aims to identify whether patients with sepsis who have persistent tachycardia despite initial resuscitation can benefit from ultrashort-acting β-blockers.

Materials and methods

Relevant studies from MEDLINE, the Cochrane Library, and Embase were searched by two independent investigators. RevMan version 5.3 (Cochrane Collaboration) was used for statistical analysis.

Results

A total of 10 studies were identified and incorporated into the meta-analysis. The results showed that the administration of ultrashort-acting β-blockers (esmolol/landiolol) in patients with sepsis with persistent tachycardia despite initial resuscitation was significantly associated with a lower 28-day mortality rate (risk ratio [RR], 0.73; 95% confidence interval [CI], 0.57-0.93; and p˂0.01). Subgroup analysis showed that the administration of esmolol in patients with sepsis was significantly associated with a lower 28-day mortality rate (RR, 0.68; 95% CI, 0.55-0.84; and p˂0.001), while there was no significant difference between the landiolol and control groups (RR, 0.98; 95% CI, 0.41-2.34; and p = 0.96). No significant differences between the two groups were found in 90-day mortality, mean arterial pressure (MAP), lactate (Lac) level, cardiac index (CI), and troponin I (TnI) at 24 h after enrollment.

Conclusion

The meta-analysis indicated that the use of esmolol in patients with persistent tachycardia, despite initial resuscitation, was linked to a notable reduction in 28-day mortality rates. Therefore, this study advocates for the consideration of esmolol in the treatment of sepsis in cases where tachycardia persists despite initial resuscitation.

Long Noncoding RNA SOX2OT Ameliorates Sepsis-Induced Myocardial Injury by Inhibiting Cellular Pyroptosis Through Mediating the EZH2/Nrf-2/NLRP3 Signaling Pathway

Objective

Cellular pyroptosis is a pro-inflammatory mode of programmed cell death that has been identified in recent years, and studies have shown that the LncRNA SOX2OT regulates myocardial injury during sepsis, but the exact regulatory mechanism is unclear. The aim of this study was to assess the role of SOX2OT in regulating cardiomyocyte injury during sepsis cardiomyopathy.

Methods

Rat cardiomyocytes, C57BL/6 mice, and transgenic mice were divided into four groups: control, LPS, LPS+ knockout LncRNA SOX2OT, and LPS+ overexpression LncRNA SOX2OT. Inflammatory factor levels were detected by qPCR. Associated proteins and gene expression were detected by Western blotting and qPCR. Dual luciferase was used to detect the target genes of SOX2OT. Nrf2 and EZH2 knockdown and overexpression cell lines were established, and the expression of related genes was detected by qPCR.

Results

Results In this study, we found that SOX2OT knockdown exacerbated LPS-induced levels of inflammatory factors and procalcitoninogen (PCT), and increased the expression of pyroptosis-related proteins and LDH. The results of dual luciferase reporter gene assay showed that EZH2 is the target gene of SOX2OT, and overexpression of SOX2OT decreased the expression of EZH2; we also found that knockdown of EZH2 in H9c2 cells decreased the expression of Nrf2, which was positively correlated with the expression level of NLRP3. Further in vivo results showed that overexpression of SOX2OT attenuated SIMD (sepsis-induced myocardial dysfunction), as evidenced by improved myocardial structural integrity and reduced inflammatory cell infiltration. The expression of pyroptosis-related proteins and LDH was significantly increased in the mice in the LPS group; this effect was reversed by overexpression of SOX2OT, and potentiated by knockdown of SOX2OT.

Conclusion

Our data reveal a novel mechanism by which SOX2OT inhibits cardiomyocyte sepsis through the EZH2/Nrf-2/NLRP3 pathway, thereby attenuating septic myocardial injury, which may contribute to the development of new therapeutic strategies.

Cardiac Magnetic Resonance Studies in a Large Animal Model that Simulates the Cardiac Abnormalities of Human Septic Shock

Background

Septic shock, in humans and in our well-established animal model, is associated with increases in biventricular end diastolic volume (EDV) and decreases in ejection fraction (EF). These abnormalities occur over 2 days and reverse within 10 days. Septic non-survivors do not develop an increase in EDV. The mechanism for this cardiac dysfunction and EDV differences is unknown.

Methods

Purpose-bred beagles randomized to receive intrabronchial Staphylococcus aureus (n=27) or saline (n=6) were provided standard ICU care including sedation, mechanical ventilation, and fluid resuscitation to a pulmonary arterial occlusion pressure of over 10mmHg. No catecholamines were administered. Over 96h, cardiac magnetic resonance imaging, echocardiograms, and invasive hemodynamics were serially performed, and laboratory data was collected. Tissue was obtained at 66h from six septic animals.

Results

From 0-96h after bacterial challenge, septic animals vs. controls had significantly increased left ventricular wall edema (6%) and wall thinning with loss of mass (15%) which was more pronounced at 48h in non-survivors than survivors. On histology, edema was located predominantly in myocytes, the interstitium, and endothelial cells. Edema was associated with significantly worse biventricular function (lower EFs), ventricular-arterial coupling, and circumferential strain. In septic animals, from 0-24h, the EDV decreased from baseline and, despite cardiac filling pressures being similar, decreased significantly more in non-survivors. From 24-48h, all septic animals had increases in biventricular chamber sizes. Survivors biventricular EDVs were significantly greater than baseline and in non-survivors, where biventricular EDVs were not different from baseline. Preload, afterload, or HR differences did not explain these differential serial changes in chamber size.

Conclusion

Systolic and diastolic cardiac dysfunction during sepsis is associated with ventricular wall edema. Rather than differences in preload, afterload, or heart rate, structural alterations to the ventricular wall best account for the volume changes associated with outcome during sepsis. In non-survivors, from 0-24h, sepsis induces a more severe diastolic dysfunction, further decreasing chamber size. The loss of left ventricular mass with wall thinning in septic survivors may, in part explain, the EDV increases from 24-48h. However, these changes continued and even accelerated into the recovery phase consistent with a reparative process rather than ongoing injury.

Prevalence and prognosis of hyperdynamic left ventricular systolic function in septic patients: a systematic review and meta-analysis

PURPOSE

The prevalence of hyperdynamic left ventricular (LV) systolic function in septic patients and its impact on mortality remain controversial. In this systematic review and meta-analysis, we investigated the prevalence and association of hyperdynamic LV systolic function with mortality in patients with sepsis.

METHODS

We searched MEDLINE, Cochrane Central Register of Controlled Trials, and Embase. Primary outcomes were the prevalence of hyperdynamic LV systolic function in adult septic patients and the associated short-term mortality as compared to normal LV systolic function. Hyperdynamic LV systolic function was defined using LV ejection fraction (LVEF) of 70% as cutoff. Secondary outcomes were heart rate, LV end-diastolic diameter (LVEDD), and E/e' ratio.

RESULTS

Four studies were included, and the pooled prevalence of hyperdynamic LV systolic function was 18.2% ([95% confidence interval (CI) 12.5, 25.8]; I2 = 7.0%, P < 0.0001). Hyperdynamic LV systolic function was associated with higher mortality: odds ratio of 2.37 [95%CI 1.47, 3.80]; I2 = 79%, P < 0.01. No difference was found in E/e' (P = 0.43) between normal and hyperdynamic LV systolic function, while higher values of heart rate (mean difference: 6.14 beats/min [95%CI 3.59, 8.69]; I2 = 51%, P < 0.0001) and LVEDD (mean difference: - 0.21 cm [95%CI - 0.33, - 0.09]; I2 = 73%, P < 0.001) were detected in patients with hyperdynamic LV systolic function.

CONCLUSION

The prevalence of hyperdynamic LV systolic function is not negligible in septic patients. Such a finding is associated with significantly higher short-term mortality as compared to normal LV systolic function.

Challenges in Septic Shock: From New Hemodynamics to Blood Purification Therapies

Sepsis and septic shock are associated with high mortality, with diagnosis and treatment remaining a challenge for clinicians. Their management classically encompasses hemodynamic resuscitation, antibiotic treatment, life support, and focus control; however, there are aspects that have changed. This narrative review highlights current and avant-garde methods of handling patients experiencing septic shock based on the experience of its authors and the best available evidence in a context of uncertainty. Following the first recommendation of the Surviving Sepsis Campaign guidelines, it is recommended that specific sepsis care performance improvement programs are implemented in hospitals, i.e., "Sepsis Code" programs, designed ad hoc, to achieve this goal. Regarding hemodynamics, the importance of perfusion and hemodynamic coherence stand out, which allow for the recognition of different phenotypes, determination of the ideal time for commencing vasopressor treatment, and the appropriate fluid therapy dosage. At present, this is not only important for the initial timing, but also for de-resuscitation, which involves the early weaning of support therapies, directed elimination of fluids, and fluid tolerance concept. Finally, regarding blood purification therapies, those aimed at eliminating endotoxins and cytokines are attractive in the early management of patients in septic shock.

Association between left ventricular systolic function parameters and myocardial injury, organ failure and mortality in patients with septic shock

BACKGROUND

Left ventricular ejection fraction (LVEF) is inconsistently associated with poor outcomes in patients with sepsis. Newer parameters such as LV longitudinal strain (LVLS), mitral annular plane systolic excursion (MAPSE) and LV longitudinal wall fractional shortening (LV-LWFS) may be more sensitive indicators of LV dysfunction, but are sparsely investigated. Our objective was to evaluate the association between five traditional and novel echocardiographic parameters of LV systolic function (LVEF, peak tissue Doppler velocity at the mitral valve (s´), LVLS, MAPSE and LV-LWFS) and outcomes in patients admitted to the Intensive Care Unit (ICU) with septic shock.

METHODS

A total of 152 patients admitted to the ICU with septic shock from two data repositories were included. Transthoracic echocardiograms were performed within 24 h of ICU admission. The primary outcome was myocardial injury, defined as high-sensitivity troponin T ≥ 45 ng/L on ICU admission. Secondary outcomes were organ support-free days (OSFD) and 30-day mortality. We also tested for the prognostic value of the systolic function parameters using multivariable analysis.

RESULTS

LVLS, MAPSE and LV-LWFS, but not LVEF and s´, differed between patients with and without myocardial injury. After adjustment for age, pre-existing cardiac disease, Simplified Acute Physiology (SAPS3) score, Sequential Organ Failure Assessment (SOFA) score, plasma creatinine and presence of right ventricular dysfunction, only MAPSE and LV-LWFS were independently associated with myocardial injury. None of the systolic function parameters were associated with OSFD or 30-day mortality.

CONCLUSIONS

MAPSE and LV-LWFS are independently associated with myocardial injury and outperform LVEF, s´ and LVLS. Whether these parameters are associated with clinical outcomes such as the need for organ support and short-term mortality is still unclear. Trial registration NCT01747187 and NCT04695119.

Diagnostic Adjunct Techniques in the Assessment of Hypovolemia: A Prospective Pilot Project

INTRODUCTION

Measuring the hypovolemic resuscitation end point remains a critical care challenge. Our project compared clinical hypovolemia (CH) with three diagnostic adjuncts: 1) noninvasive cardiac output monitoring (NICOM), 2) ultrasound (US) static IVC collapsibility (US-IVC), and 3) US dynamic carotid upstroke velocity (US-C). We hypothesized US measures would correlate more closely to CH than NICOM.

METHODS

Adult trauma/surgical intensive care unit patients were prospectively screened for suspected hypovolemia after acute resuscitation, excluding patients with burns, known heart failure, or severe liver/kidney disease. Adjunct measurements were assessed up to twice a day until clinical improvement. Hypovolemia was defined as: 1) NICOM: ≥10% stroke volume variation with passive leg raise, 2) US-IVC: <2.1 cm and >50% collapsibility (nonventilated) or >18% collapsibility (ventilated), 3) US-C: peak systolic velocity increase 15 cm/s with passive leg raise. Previously unknown cardiac dysfunction seen on US was noted. Observation-level data were analyzed with a Cohen's kappa (κ).

RESULTS

44 patients (62% male, median age 60) yielded 65 measures. Positive agreement with CH was 47% for NICOM, 37% for US-IVC and 10% for US-C. None of the three adjuncts correlated with CH (κ -0.045 to 0.029). After adjusting for previously unknown cardiac dysfunction present in 10 patients, no adjuncts correlated with CH (κ -0.036 to 0.031). No technique correlated with any other (κ -0.118 to 0.083).

CONCLUSIONS

None of the adjunct measurements correlated with CH or each other, highlighting that fluid status assessment remains challenging in critical care. US should assess for right ventricular dysfunction prior to resuscitation.

Research Progress on the Mechanism and Management of Septic Cardiomyopathy: A Comprehensive Review

Sepsis is defined as a kind of life-threatening organ dysfunction due to a dysregulated host immune response to infection and is a leading cause of mortality in the intensive care unit. Sepsis-induced myocardial dysfunction, also called septic cardiomyopathy, is a common and serious complication in patients with sepsis, which may indicate a bad prognosis. Although efforts have been made to uncover the pathophysiology of septic cardiomyopathy, a number of uncertainties remain. This article sought to review available literature to summarize the existing knowledge on current diagnostic tools and biomarkers, pathogenesis, and treatments for septic cardiomyopathy.

Mitral annular plane systolic excursion for assessing left ventricular systolic dysfunction in patients with septic shock

Background

Using easy-to-determine bedside measurements, we developed an echocardiographic algorithm for predicting left ventricular ejection fraction (LVEF) and longitudinal strain (LVLS) in patients with septic shock.

Methods

We measured septal and lateral mitral annular plane systolic excursion (MAPSE), septal and lateral mitral S-wave velocity, and the left ventricular longitudinal wall fractional shortening in patients with septic shock. We used a conditional inference tree method to build a stratification algorithm. The left ventricular systolic dysfunction was defined as an LVEF <50%, an LVLS greater than -17%, or both.

Results

We included 71 patients (males: 61%; mean [standard deviation] age: 61 [15] yr). Septal MAPSE (cut-off: 1.2 cm) was the best predictor of left ventricular systolic dysfunction. The level of agreement between the septal MAPSE and the left ventricular systolic dysfunction was 0.525 [0.299-0.751]. A septal MAPSE ≥1.2 cm predicted normal LVEF in 17/18 patients, or 94%. In contrast, a septal MAPSE <1.2 cm predicted left ventricular systolic dysfunction with impaired LVLS in 46/53 patients (87%), although 32/53 (60%) patients had a preserved LVEF.

Conclusions

Septal MAPSE is easily measured at the bedside and might help clinicians to detect left ventricular systolic dysfunction early-especially when myocardial strain measurements are not feasible.

Correlation between tissue Doppler-derived left ventricular systolic velocity (S') and left ventricle ejection fraction in sepsis and septic shock: a retrospective cohort study

BACKGROUND

Tissue Doppler-derived left ventricular systolic velocity (mitral S') has shown excellent correlation to left ventricular ejection fraction (LVEF) in non-critically patients. However, their correlation in septic patients remains poorly understood and its impact on mortality is undetermined. We investigated the relationship between mitral S' and LVEF in a large cohort of critically-ill septic patients.

METHODS

We conducted a retrospective cohort study between 01/2011 and 12/2020. All adult patients (≥ 18 years) who were admitted to the medical intensive care unit (MICU) with sepsis and septic shock that underwent a transthoracic echocardiogram (TTE) within 72 h were included. Pearson correlation test was used to assess correlation between average mitral S' and LVEF. Pearson correlation was used to assess correlation between average mitral S' and LVEF. We also assessed the association between mitral S', LVEF and 28-day mortality.

RESULTS

2519 patients met the inclusion criteria. The study population included 1216 (48.3%) males with a median age of 64 (IQR: 53-73), and a median APACHE III score of 85 (IQR: 67, 108). The median septal, lateral, and average mitral S' were 8 cm/s (IQR): 6.0, 10.0], 9 cm/s (IQR: 6.0, 10.0), and 8.5 cm/s (IQR: 6.5, 10.5), respectively. Mitral S' was noted to have moderate correlation with LVEF (r = 0.46). In multivariable logistic regression analysis, average mitral S' was associated with an increase in both 28-day ICU and in-hospital mortality with odds ratio (OR) 1.04 (95% CI 1.01-1.08, p = 0.02) and OR 1.04 (95% CI 1.01-1.07, p = 0.02), respectively.

CONCLUSIONS

Even though mitral S' and LVEF may be related, they are not exchangeable and were only found to have moderate correlation in this study. LVEF is U-shaped, while mitral S' has a linear relation with 28-day ICU mortality. An increase in average mitral S' was associated with higher 28-day mortality.

Association of sepsis-induced cardiomyopathy and mortality: a systematic review and meta-analysis

BACKGROUND

The implication of sepsis-induced cardiomyopathy (SIC) to prognosis is controversial, and its association with mortality at different stages remains unclear. We conducted a systematic review and meta-analysis to understand the association between SIC and mortality in septic patients.

METHODS

We searched and appraised observational studies regarding the mortality related to SIC among septic patients in PubMed and Embase from inception until 8 July 2021. Outcomes comprised in-hospital and 1-month mortality. We adopted the random-effects model to examine the mortality risk ratio in patients with and without SIC. Meta-regression, subgroup, and sensitivity analyses were applied to examine the outcome's heterogeneity.

RESULTS

Our results, including 20 studies and 4,410 septic patients, demonstrated that SIC was non-statistically associated with increased in-hospital mortality, compared to non-SIC (RR 1.28, [0.96-1.71]; p = 0.09), but the association was statistically significant in patients with the hospital stay lengths longer than 10 days (RR 1.40, [1.02-1.93]; p = 0.04). Besides, SIC was significantly associated with a higher risk of 1-month mortality (RR 1.47, [1.17-1.86]; p < 0.01). Among SIC patients, right ventricular dysfunction was significantly associated with increased 1-month mortality (RR 1.72, [1.27-2.34]; p < 0.01), while left ventricular dysfunction was not (RR 1.33, [0.87-2.02]; p = 0.18).

CONCLUSIONS

With higher in-hospital mortality in those hospitalized longer than 10 days and 1-month mortality, our findings imply that SIC might continue influencing the host's system even after recovery from cardiomyopathy. Besides, right ventricular dysfunction might play a crucial role in SIC-related mortality, and timely biventricular assessment is vital in managing septic patients.

A multicenter prospective cohort study of cardiac ultrasound phenotypes in patients with sepsis: Study protocol for a multicenter prospective cohort trial

Background

Sepsis-induced cardiomyopathy significantly increased the mortality of patients with sepsis. The diagnostic criteria for septic cardiomyopathy has not been unified, which brings serious difficulties to clinical treatment. This study aimed to provide evidence for the early identification and intervention in patients with sepsis by clarifying the relationship between the ultrasound phenotype of septic cardiomyopathy and the prognosis of patients with sepsis.

Methods

This was a multicenter, prospective cohort study. The study population will consist of all eligible consecutive patients with sepsis or septic shock who meet the Sepsis 3.0 diagnostic criteria and were aged ≥18 years. Clinical data and echocardiographic measurements will be recorded within 2 h, at the 24th hour, at the 72nd hour, and on the 7th day after admission. The prevalence of each phenotype will be described as well, and their association with prognosis will be analyzed statistically.

Discussion

To achieve early recognition, prevent reinjury, achieve precise treatment, and reduce mortality in patients with sepsis, it is important to identify septic cardiac alterations and classify the phenotypes at all stages of sepsis. First, there is a lack of studies on the prevalence of each phenotype in Chinese populations. Second, each phenotype and its corresponding prognosis are not clear. In addition, the prognosis of patients with normal cardiac ultrasound phenotypes vs. those with suppressed or hyperdynamic cardiac phenotypes is unclear. Finally, this study was designed to collect data at four specific timing, then the timing of occurrence, duration, changes over time, impact to outcomes of each phenotype will probably be found. This study is expected to establish a standard and objective method to assess the ultrasound phenotype of septic cardiomyopathy due to its advantages of visualization, non-invasiveness and reproducibility, and to provide more precise information for the hemodynamic management of septic patients. In addition, this research will promote the clinical application of critical care ultrasound, which will play an important role in medical education and make ultrasound the best method to assess cardiac changes in sepsis.

Trial registration

https://clinicaltrials.gov/ct2/show/NCT05161104, identifier NCT05161104.

A Prospective Observational Study to Determine Incidence and Outcome of Sepsis-induced Cardiomyopathy in an Intensive Care Unit

Introduction

Sepsis leads to left and/or right ventricular systolic and/or diastolic dysfunction resulting in adverse outcomes. Myocardial dysfunction can be diagnosed by echocardiography (ECHO) and early intervention can be planned. There are lacunae in Indian literature regarding the true incidence of septic cardiomyopathy and its influence on the outcome of patients admitted to intensive care unit (ICU).

Materials and methods

This prospective observational study was conducted on patients consecutively admitted with sepsis to the ICU of a tertiary care hospital in North India. In these patients, ECHO was performed after 48-72 hours to establish left ventricular (LV) dysfunction, in whom the ICU outcome was analyzed.

Result

The incidence of LV dysfunction was 14%. About 42.86% of patients had isolated systolic dysfunction, 7.14% of patients had isolated diastolic dysfunction, and 50.00% of patients had combined LV systolic and diastolic dysfunctions. The average days of mechanical ventilation in patients without LV dysfunction group (group I) was 2.41 ± 3.82 days as compared to 4.43 ± 4.27 days in patients with LV dysfunction (group II) (p = 0.034). Incidence of all-cause ICU mortality was 11 (12.79%) in group I and 3 (21.43%) in group II (p = 0.409). The mean duration of stay in ICU was 8.26 ± 4.41 days in group I as compared to 13.21 ± 6.83 days in group II.

Conclusion

We concluded that sepsis-induced cardiomyopathy (SICM) in ICU is quite prevalent and clinically significant. All-cause ICU mortality and length of ICU stay are prolonged in patients with SICM.

How to cite this article

Bansal S, Varshney S, Shrivastava A. A Prospective Observational Study to Determine Incidence and Outcome of Sepsis-induced Cardiomyopathy in an Intensive Care Unit. Indian J Crit Care Med 2022;26(7):798-803.

Risk factors of postoperative septic cardiomyopathy in perioperative sepsis patients

Objective

This study aimed to clarify the relevant risk factors of septic cardiomyopathy (SCM) in perioperative sepsis patients.

Methods

This retrospective study evaluated patients who were diagnosed with sepsis during the perioperative period and postoperatively admitted to the intensive care unit (ICU) in the Second Affiliated Hospital of Soochow University, the First Affiliated Hospital of Soochow University, and the Suzhou Municipal Hospital between January 2017 and November 2020. They were divided into two groups as the septic cardiomyopathy group (SCM group) and the non-SCM group (NSCM group). Factors with P < 0.1 were compared between groups and were analyzed by multivariate logistic regression to screen the risk factors of sepsis cardiomyopathy. The area under the receiver operating characteristic (ROC) curve was used to verify the discriminative ability of multivariate logistic regression results. Hosmer-Lemeshow goodness of fit test was used to verify the calibration ability of multiple logistic regression results.

Result

Among the 269 patients, 49 patients had SCM. Sequential Organ Failure Assessment (SOFA) score (adjusted odds ratio [AOR] = 2.535, 95% confidence interval (CI): 1.186-1.821, P = 0.000]) and endoscopic surgery (AOR = 3.154, 95% CI: 1.173-8.477, P = 0.023]) were identified to be independent risk factors for SCM. Patients with a SOFA score ≥ 7 had a 46.831-fold higher risk of SCM (AOR =46.831, 95% CI: 10.511-208.662, P < 0.05). The multivariate logistic regression results had good discriminative (area under the curve: 0.902 [95% CI: 0.852-0.953]) and calibration (c² = 4.401, P = 0.819) capabilities. The predictive accuracy was 86.2%. The rates of mechanical ventilation and tracheotomy were significantly higher in the SCM group than in the NSCM group (both P < 0.05). The SCM group also had a significantly longer duration of mechanical ventilation (P < 0.05) and significantly higher rates of continuous renal replacement therapy (CRRT) and CRRT-related mortality (P < 0.05). Further, the total length of stay and hospitalization cost were significantly higher in the SCM group than in the NSCM group (P < 0.05).

Conclusion

Endoscopic surgery and SOFA score ≥ 7 during postoperative ICU admission were independent risk factors for SCM within 48 hours postoperatively in patients with perioperative sepsis.

Biomarkers Predicting Tissue Pharmacokinetics of Antimicrobials in Sepsis: A Review

The pathophysiology of sepsis alters drug pharmacokinetics, resulting in inadequate drug exposure and target-site concentration. Suboptimal exposure leads to treatment failure and the development of antimicrobial resistance. Therefore, we seek to optimize antimicrobial therapy in sepsis by selecting the right drug and the correct dosage. A prerequisite for achieving this goal is characterization and understanding of the mechanisms of pharmacokinetic alterations. However, most infections take place not in blood but in different body compartments. Since tissue pharmacokinetic assessment is not feasible in daily practice, we need to tailor antibiotic treatment according to the specific patient’s pathophysiological processes. The complex pathophysiology of sepsis and the ineffectiveness of current targeted therapies suggest that treatments guided by biomarkers predicting target-site concentration could provide a new therapeutic strategy. Inflammation, endothelial and coagulation activation markers, and blood flow parameters might be indicators of impaired tissue distribution. Moreover, hepatic and renal dysfunction biomarkers can predict not only drug metabolism and clearance but also drug distribution. Identification of the right biomarkers can direct drug dosing and provide timely feedback on its effectiveness. Therefore, this might decrease antibiotic resistance and the mortality of critically ill patients. This article fills the literature gap by characterizing patient biomarkers that might be used to predict unbound plasma-to-tissue drug distribution in critically ill patients. Although all biomarkers must be clinically evaluated with the ultimate goal of combining them in a clinically feasible scoring system, we support the concept that the appropriate biomarkers could be used to direct targeted antibiotic dosing.

Septic cardiomyopathy: Diagnosis and management

There is an extensive body of literature focused on sepsis-induced myocardial dysfunction, but results are conflicting and no objective definition of septic cardiomyopathy (SCM) has been established. SCM may be defined as a sepsis-associated acute syndrome of non-ischemic cardiac dysfunction with systolic and/or diastolic left ventricular (LV) dysfunction and/or right ventricular dysfunction. Physicians should consider this diagnosis in patients with sepsis-associated organ dysfunction, and particularly in cases of septic shock that require vasopressors. Echocardiography is currently the gold standard for diagnosis of SCM. Left ventricular ejection fraction is the most common parameter used to describe LV function in the literature, but its dependence on loading conditions, particularly afterload, limits its use as a measure of intrinsic myocardial contractility. Therefore, repeated echocardiography evaluation is mandatory. Evaluation of global longitudinal strain (GLS) may be more sensitive and specific for SCM than LV ejection fraction (LVEF). Standard management includes etiological treatment, adapted fluid resuscitation, use of vasopressors, and monitoring. Use of inotropes remains uncertain, and heart rate control could be an option in some patients.

Levosimendan versus dobutamine for sepsis-induced cardiac dysfunction: a systematic review and meta-analysis

Levosimendan and dobutamine are extensively used to treat sepsis-associated cardiovascular failure in ICU. Nevertheless, the role and mechanism of levosimendan in patients with sepsis-induced cardiomyopathy remains unclear. Moreover, previous studies on whether levosimendan is superior to dobutamine are still controversial. More importantly, these studies did not take changes (before-after comparison to the baseline) in quantitative parameters such as ejection fraction into account with the baseline level. Here, we aimed to determine the pros and cons of the two medicines by assessing the changes in cardiac function and blood lactate, mortality, with the standardized mean difference used as a summary statistic. Relevant studies were obtained by a thorough and disciplined literature search in several notable academic databases, including Google Scholar, PubMed, Cochrane Library and Embase until November 2020. Outcomes included changes in cardiac function, lactic acid, mortality and length of hospital stay. A total of 6 randomized controlled trials were included in this study, including 192 patients. Compared with dobutamine, patients treated with levosimendan had a greater improvement of cardiac index (ΔCI) (random effects, SMD = 0.90 [0.20,1.60]; I2 = 76%, P < 0.01) and left ventricular stroke work index (ΔLVSWI) (random effects, SMD = 1.56 [0.90,2.21]; I2 = 65%, P = 0.04), a significant decrease of blood lactate (Δblood lactate) (random effects, MD =  - 0.79 [- 1.33, - 0.25]; I2 = 68%, P < 0.01) at 24-h after drug intervention, respectively. There was no significant difference between levosimendan and dobutamine on all-cause mortality in ICU (fixed effect, OR = 0.72 [0.39,1.33]; I2 = 0%, P = 0.99). We combine effect sizes related to different measurement parameters to evaluate cardiac function, which implied that septic patients with myocardial dysfunction might have a better improvement of cardiac function by levosimendan than dobutamine (random effects, SMD = 1.05 [0.69,1.41]; I2 = 67%, P < 0.01). This study suggested a significant improvement of CI, LVSWI, and decrease of blood lactate in septic patients with myocardial dysfunction in ICU after 24-h administration of levosimendan than dobutamine. However, the administration of levosimendan has neither an impact on mortality nor LVEF. Septic patients with myocardial dysfunction may partly benefit from levosimendan than dobutamine, mainly embodied in cardiac function improvement.

Afterload-related cardiac performance predicts prognosis in critical ill patients with sepsis: A prospective observational pilot study

ABSTRACT

To investigate the usefulness of afterload-related cardiac performance (ACP) for assessing cardiac impairment and predicting prognosis in septic patients.Adult patients with sepsis in the intensive care unit were included. Cardiac output, cardiac index, cardiac power index, and ACP were calculated at the time of admission (D0) and 48-72 h after admission (D3). They were correlated with Acute Physiology and Chronic Health Evaluation II and sequential organ failure assessment scores, then the prognostic values were analyzed.A total of 41 patients with sepsis were selected. ACP showed a stronger negative correlation with Acute Physiology and Chronic Health Evaluation II and sequential organ failure assessment scores than cardiac output, cardiac index, and cardiac power index. ACP predicted 28-day mortality with an area under the curve of 0.775 and 0.976 on D0 and D3, respectively. In addition, most non-survivors had emergent cardiac impairment (ACP ≤ 80%) on D0, and cardiac function was deteriorated on D3. Survival analysis showed that the patients with a decreased ACP from D0 to D3 had the highest mortality. The decrease of ACP on D3 was an independent risk factor for mortality (hazard ratio, 11.89; P = .0028).ACP can be used to assess the severity of cardiac impairment in sepsis. Continued decline of ACP during the first 3 days strongly suggests a poor prognosis.

Hydrocortisone, Ascorbic Acid, and Thiamine (HAT) Therapy Decreases Oxidative Stress, Improves Cardiovascular Function, and Improves Survival in Murine Sepsis

INTRODUCTION

A small clinical trial showed HAT therapy improved survival but no studies have been reported in animal models to examine potential mechanisms.

METHODS

Sepsis was induced in female mice using the cecal ligation and puncture (CLP) model. Physiologic parameters including heart rate (HR), pulse distension (PD), and respiratory rate (RR) were measured noninvasively at baseline, 6 and 24 h post CLP. These measurements stratified mice into predicted to live (Live-P) or die (Die-P). Mice were randomized to receive HAT therapy or vehicle. Oxidative stress was measured in peritoneal exudative cells 24 h after CLP.

RESULTS

HR, PD, and RR all declined within the first 6 h of sepsis and were significantly lower in the Die-P mice compared with Live-P. HR 6 h post-CLP best predicted mortality and continued to decline between 6 and 24 h post CLP. Oxidative stress in peritoneal cells harvested 24 h post CLP (determined by 8 isoprostaglandin F2α and protein carbonyl derivatives) was significantly higher in the Die-P mice. HAT therapy was initiated 7 h post-CLP after mortality prediction and stratification. HAT significantly reduced oxidative stress in the Die-P mice without altering these parameters in the Live-P mice. HAT treatment prevented the decline in HR, again only in the Die-P mice. Mice treated with HAT therapy had significantly better survival.

CONCLUSIONS

Physiologic parameters accurately predicted mortality. Die-P mice had significant oxidative stress compared with Live-P. HAT therapy significantly decreased oxidative stress, increased HR, and improved survival in the Die-P mice. These data suggest that HAT exerts a beneficial effect through reducing oxidative stress and improving cardiovascular function.

Left ventricular longitudinal wall fractional shortening accurately predicts longitudinal strain in critically ill patients with septic shock

Background

Left ventricular longitudinal strain (LVLS) may be a sensitive indicator of left ventricular (LV) systolic function in patients with sepsis, but is dependent on high image quality and analysis software. Mitral annular plane systolic excursion (MAPSE) and the novel left ventricular longitudinal wall fractional shortening (LV-LWFS) are bedside echocardiographic indicators of LV systolic function that are less dependent on image quality. Both are sparsely investigated in the critically ill population, and may potentially be used as surrogates for LVLS. We assessed if LVLS may be predicted by LV-LWFS and MAPSE in patients with septic shock. We also assessed the repeatability and inter-rater agreement of LVLS, LV-LWFS and MAPSE measurements.

Results

122 TTE studies from 3 echocardiographic data repositories of patients admitted to ICU with septic shock were retrospectively assessed, of which 73 were suitable for LVLS analysis using speckle tracking. The correlations between LVLS vs. LV-LWFS and LVLS vs. MAPSE were 0.89 (p < 0.001) and 0.81 (p < 0.001) with mean squared errors of 5.8% and 9.1%, respectively. Using the generated regression equation, LV-LWFS predicted LVLS with a high degree of accuracy and precision, with bias and limits of agreement of -0.044 ± 4.7% and mean squared prediction error of 5.8%. Interobserver repeatability was good, with high intraclass correlation coefficients (0.96–0.97), small bias and tight limits of agreement (≤ 4.1% for all analyses) between observers for all measurements.

Conclusions

LV-LWFS may be used to estimate LVLS in patients with septic shock. MAPSE also performed well, but was slightly inferior compared to LV-LWFS in estimating LVLS. Feasibility of MAPSE and LV-LWFS was excellent, as was interobserver repeatability.

FAM134B-mediated endoplasmic reticulum autophagy protects against sepsis myocardial injury in mice

Reticulophagy regulator 1 (RETEG1, also known as FAM134B) plays a crucial role in endoplasmic reticulum autophagy. We aimed to explore the effect of FAM134B-mediated endoplasmic reticulum autophagy in sepsis myocardial injury in mice. Sepsis myocardial injury mice were established via cecal ligation and puncture procedures. The expression of FAM134B and LC3-II/I was determined using immunohistochemistry. Myocardial tissue morphological changes and apoptosis were examined using hematoxylin and eosin (H&E) staining and TUNEL analysis. The effects of FAM134B knockdown or overexpression on mice with sepsis myocardial injury were also studied. The levels of TNF-α, IL-6, IL-8, and IL-10 were evaluated using enzyme-linked immunosorbent assay (ELISA). Autophagy- and apoptosis-related protein expression was detected using western blotting. The effect of FAM134B on Lipopolysaccharide (LPS) -induced cardiomyocytes was also studied. The expression of FAM134B and LC3-II/I increased in sepsis mice and lipopolysaccharide (LPS)-treated cardiomyocytes. 3-Methyladenine (3-MA) significantly inhibited FAM134B and LC3-II/I expression and promoted myocardial injury, inflammation response, and cardiomyocyte apoptosis. The overexpression of FAM134B could minimize myocardial injury, inflammation, and apoptosis, whereas FAM134B knockdown showed opposite effects. FAM134B-mediated endoplasmic reticulum autophagy had a protective effect on sepsis myocardial injury in mice by reducing inflammation and tissue apoptosis, which may provide new insights for sepsis myocardial injury therapies.

Sectm1a deficiency aggravates inflammation-triggered cardiac dysfunction through disruption of LXRα signalling in macrophages

AIMS

Cardiac dysfunction is a prevalent comorbidity of disrupted inflammatory homeostasis observed in conditions such as sepsis (acute) or obesity (chronic). Secreted and transmembrane protein 1a (Sectm1a) has previously been implicated to regulate inflammatory responses, yet its role in inflammation-associated cardiac dysfunction is virtually unknown.

METHODS AND RESULTS

Using the CRISPR/Cas9 system, we generated a global Sectm1a-knockout (KO) mouse model and observed significantly increased mortality and cardiac injury after lipopolysaccharide (LPS) injection, when compared with wild-type (WT) control. Further analysis revealed significantly increased accumulation of inflammatory macrophages in hearts of LPS-treated KO mice. Accordingly, ablation of Sectm1a remarkably increased inflammatory cytokines levels both in vitro [from bone marrow-derived macrophages (BMDMs)] and in vivo (in serum and myocardium) after LPS challenge. RNA-sequencing results and bioinformatics analyses showed that the most significantly down-regulated genes in KO-BMDMs were modulated by LXRα, a nuclear receptor with robust anti-inflammatory activity in macrophages. Indeed, we identified that the nuclear translocation of LXRα was disrupted in KO-BMDMs when treated with GW3965 (LXR agonist), resulting in higher levels of inflammatory cytokines, compared to GW3965-treated WT-cells. Furthermore, using chronic inflammation model of high-fat diet (HFD) feeding, we observed that infiltration of inflammatory monocytes/macrophages into KO-hearts were greatly increased and accordingly, worsened cardiac function, compared to WT-HFD controls.

CONCLUSION

This study defines Sectm1a as a new regulator of inflammatory-induced cardiac dysfunction through modulation of LXRα signalling in macrophages. Our data suggest that augmenting Sectm1a activity may be a potential therapeutic approach to resolve inflammation and associated cardiac dysfunction.

Systolic dysfunction as evaluated by tissue Doppler imaging echocardiography and mortality in septic patients: A systematic review and meta-analysis

PURPOSE

Septic induced cardiomyopathy has a wide spectrum of presentation, being associated with systolic and/or diastolic dysfunction. There is currently no evidence of association between left ventricular (LV) systolic dysfunction and mortality in septic patients.

METHODS

We conducted a systematic review and meta-analysis to investigate the association between systolic wave (s') obtained with Tissue Doppler Imaging (TDI) and mortality in septic patients. Secondary outcome was the association of LV ejection fraction with mortality.

RESULTS

In the primary analysis we included a total of 13 studies (1197 patients, mortality 39.9%); overall s' wave was not significantly different between survivors and non-survivors (Standardized Mean Difference 0.20, 95%Confidence-Interval - 0.18, 0.59). This result was confirmed also in sub-groups analyses according to regional criteria of TDI sampling. A post-hoc analysis including only septic shock patients confirmed that s' wave was not associated with mortality. Several sensitivity analyses confirmed these results. We found no evidence of publication bias. The secondary analysis (11 studies, 1081 patients, mortality 36.7%) showed that LV ejection fraction was not associated with mortality (Mean Difference 0.98, 95% Confidence-Interval - 1.79,3.75).

CONCLUSIONS

There is no association between mortality and LV systolic function as evaluated by TDI s' wave in septic patients.

Septic Cardiomyopathy: From Basics to Management Choices

Septic cardiomyopathy (SCM) is increasingly recognized as a potential complication of septic shock; it is understood to be a reversible left ventricular systolic dysfunction. The presence of SCM in septic shock, in previous studies, infer a poorer prognosis as it significantly increases the mortality rate of patients to 70%-90% and its incidence varies from 18% to 40% of septic shock patients. The pathogenesis is unclear, but believed to be a combination of bacterial toxins, cytokines, nitric oxide, and cardiac mitochondrial dysfunction, that depresses intrinsic cardiac contractility. The presence of SCM can be diagnosed in patients using a bedside transthoracic echocardiogram which typically shows left ventricular ejection fraction <45% and right ventricular dilatation. For management, levosimendan provides a good hemodynamic response without increasing cardiac oxygen demand when compared to dobutamine, while more invasive techniques such as extracorporeal membrane oxygenation, and intra-aortic balloon pulsation are being explored as well as potential rescue strategies for patients with severe SCM.

Overexpression of miR-451a in sepsis and septic shock patients is involved in the regulation of sepsis-associated cardiac dysfunction and inflammation

The purpose of this study was to investigate the expression and clinical value of microRNA-451a (miR-451a) in septic patients and analyze its effect on sepsis-associated cardiac dysfunction and inflammation response. A rat model of sepsis was constructed by cecal ligation and puncture. The expression of miR-451a was measured by quantitative real-time PCR. Receiver operating characteristic (ROC) analysis was used to assess the diagnostic value of serum miR-451a. The cardiac function and inflammatory responses in septic rats were measured to explore the functional role of miR-451a. Serum expression of miR-451a was increased in septic patients compared with healthy controls, and had the ability to distinguish septic patients from healthy volunteers with a sensitivity and specificity of 87.8% and 81.5%, respectively. Elevated serum miR-451a was associated with sepsis severity, as evidenced by the increased expression of miR-451a in septic shock patients and its correlation with key clinical indicators. Significantly upregulated expression of miR-451a was found in septic patients with cardiac dysfunction, and the knockdown of miR-451a in sepsis rats improved cardiac function and inhibited inflammatory responses. All the data revealed that serum miR-451a serves as a candidate diagnostic biomarker of sepsis and a potential parameter to indicate disease severity. The reduction of miR-451a may mitigate sepsis-induced cardiac dysfunction and inflammatory responses.

GFI-1 Protects Against Lipopolysaccharide-Induced Inflammatory Responses and Apoptosis by Inhibition of the NF-κB/TNF-α Pathway in H9c2 Cells

Growth factor independence 1 (Gfi-1) has been widely studied for its anti-inflammatory and anti-apoptotic effects. However, whether Gfi-1 has similar effects on H9c2 cardiomyocytes has not yet been reported. In this study, we explored the effect of Gfi-1 on lipopolysaccharide (LPS)-induced inflammatory responses and apoptosis in H9c2 cells. We found that LPS induced the increased expression of TNF-α and IL-6 in the LPS group. After transfection of the Gfi-1 overexpression plasmid, the expression of TNF-α and IL-6 decreased significantly in the LPS + Gfi-1 group. Gfi-1 clearly blocked LPS-induced NF-κB, TNF-α, TNFR1, cleaved-caspase-3 and cleaved-caspase-8 expression and increased Gfi-1 and Bcl-xL expression in H9c2 cells. Similarly, compared with the LPS group, Gfi-1 significantly decreased the expression of cleaved-caspase3/8 and increased the expression of Bcl-xL in the LPS + Gfi-1 group, as verified by immunocytochemical analysis. Furthermore, Gfi-1 markedly inhibited LPS-induced H9c2 cardiomyocyte apoptosis in the LPS + Gfi-1 group, as determined by TEM, TUNEL and flow cytometry. Taken together, these results demonstrate that Gfi-1 may have protective effects against LPS-induced inflammatory responses and apoptosis in H9c2 cells. Gfi-1 may be a novel molecule for treating septic cardiomyopathy.

Factors associated with abnormal left ventricular ejection fraction (decreased or increased) in patients with sepsis in the intensive care unit

BACKGROUND

Sepsis-induced cardiomyopathy (SIC) is known to show cardiac dysfunction in patients with sepsis. Both a decrease or an increase in ejection fraction (EF), an indicator of cardiac function, can occur. The purpose of this study was to identify factors associated with abnormal left ventricular (LV) function measured by EF in patients with sepsis in the intensive care unit (ICU).

METHODS

This was a retrospective study performed from November 2016 to December 2018. Three-hundred and sixty-six patients (mean age, 73 ± 13 years; 191 [52%] men) admitted to the ICU with sepsis were included. Patients were classified into three categories according to LV EF (group 1 -[EF<50%, n = 36], group 2 -[50≤EF<70%, n = 252], and group 3 -[EF≥70%, n = 78]). Echocardiographic assessment was performed within 48 hours of diagnosis of sepsis. We analyzed clinical factors including mortality, echocardiographic findings, and laboratory parameters.

RESULTS

Decreased LV EF occurred in 36 (10%) patients and hyper-dynamic EF developed in 78 (21%) patients. Of 366 patients, 103 (28%) patients died. Baseline characteristics were similar in the three groups, except female sex an indicator of abnormal EF. Mortality rates were also similar in the three groups; however, mortality rates were significantly higher in patients with abnormal EF (decreased or increased vs. normal). Echocardiographic parameters were significantly different in the three groups, in terms of LV systolic parameters and chamber size. Small left atrium (LA) and small LV were significantly associated with abnormal EF (especially in patients with increased EF). High brain natriuretic peptide was associated with decreased EF. Among these factors, female sex and small LA were significantly associated with abnormal EF in the multiple regression analysis.

CONCLUSION

Our findings highlight that female sex and small cardiac size are associated with abnormal EF, and therefore, death. Therefore, female patients and patients with small LA should be monitored closely when they present with sepsis.

PKCδ causes sepsis-induced cardiomyopathy by inducing mitochondrial dysfunction

Sepsis-induced cardiomyopathy (SIC) is associated with increased patient mortality. At present, there are no specific therapies for SIC. Previous studies have reported increased reactive oxygen species (ROS) and mitochondrial dysfunction during SIC. However, a unifying mechanism remains to be defined. We hypothesized that PKCδ is required for abnormal calcium handling and cardiac mitochondrial dysfunction during sepsis and that genetic deletion of PKCδ would be protective. Polymicrobial sepsis induced by cecal ligation and puncture (CLP) surgery decreased the ejection fraction of wild-type (WT) mice but not PKCδ knockout (KO) mice. Similarly, WT cardiomyocytes exposed to lipopolysaccharide (LPS) demonstrated decreases in contractility and calcium transient amplitude that were not observed in PKCδ KO cardiomyocytes. LPS treatment decreased sarcoplasmic reticulum calcium stores in WT cardiomyocytes, which correlated with increased ryanodine receptor-2 oxidation in WT hearts but not PKCδ KO hearts after sepsis. LPS exposure increased mitochondrial ROS and decreased mitochondrial inner membrane potential in WT cardiomyocytes. This corresponded to morphologic changes consistent with mitochondrial dysfunction such as decreased overall size and cristae disorganization. Increased cellular ROS and changes in mitochondrial morphology were not observed in PKCδ KO cardiomyocytes. These data show that PKCδ is required in the pathophysiology of SIC by generating ROS and promoting mitochondrial dysfunction. Thus, PKCδ is a potential target for cardiac protection during sepsis.NEW & NOTEWORTHY Sepsis is often complicated by cardiac dysfunction, which is associated with a high mortality rate. Our work shows that the protein PKCδ is required for decreased cardiac contractility during sepsis. Mice with deletion of PKCδ are protected from cardiac dysfunction after sepsis. PKCδ causes mitochondrial dysfunction in cardiac myocytes, and reducing mitochondrial oxidative stress improves contractility in wild-type cardiomyocytes. Thus, PKCδ is a potential target for cardiac protection during sepsis.

Current Status of Septic Cardiomyopathy: Basic Science and Clinical Progress

Septic cardiomyopathy (SCM) is a complication that is sepsis-associated cardiovascular failure. In the last few decades, there is progress in diagnosis and treatment despite the lack of consistent diagnostic criteria. According to current studies, several hypotheses about pathogenic mechanisms have been revealed to elucidate the pathophysiological characteristics of SCM. The objective of this manuscript is to review literature from the past 5 years to provide an overview of current knowledge on pathogenesis, diagnosis and treatment in SCM.

MicroRNA-181a-5p Regulates Inflammatory Response of Macrophages in Sepsis

The aim of this study was to evaluate the role of miR-181a-5p in sepsis, and to further explore the molecular mechanism. RAW 264.7 cells were stimulated with 1 μg/ml LPS for 4 hours. Firstly, qRT-PCR and ELISA was adopted to evaluate the expression of miR-181a-5p and p ro-inflammatory cytokines in RAW 264.7 macrophages a fter LPS stimulation. Results showed that pro-inflammatory cytokines and miR-181a-5p were significantly increased after LPS treatment. Then, we identified that sirtuin-1 (SIRT1) was a direct target of miR-181a-5p and it was down-regulated in LPS treated RAW264.7 macrophages. Furthermore, the data suggested that the miR-181a-5p inhibitor significantly inhibited LPS enhanced inflammatory cytokines expression and NF-κB pathway activation, and these changes were eliminated by SIRT1 silencing. Moreover, the role of the miR-181a-5p inhibitor on sepsis was studied in vivo. We found that the miR-181a-5p inhibitor significantly decreased the secretion of inflammatory factors, and the levels of creatine (Cr), blood urea nitrogen (BUN), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in a serum for mice with sepsis. However, all the effects were reversed by SIRT1-siRNA. In summary, these results indicated that miR-181a-5p was involved in sepsis through regulating the inflammatory response by targeting SIRT1, suggesting that miR-181a-5p may be a potential target for the treatment of sepsis.

Tumor susceptibility gene 101 ameliorates endotoxin-induced cardiac dysfunction by enhancing Parkin-mediated mitophagy

Cardiac mitochondrial damage and subsequent inflammation are hallmarks of endotoxin-induced myocardial depression. Activation of the Parkin/PTEN-induced kinase 1 (PINK1) pathway has been shown to promote autophagy of damaged mitochondria (mitophagy) and to protect from endotoxin-induced cardiac dysfunction. Tumor susceptibility gene 101 (TSG101) is a key member of the endosomal recycling complexes required for transport, which may affect autophagic flux. In this study, we investigated whether TSG101 regulates mitophagy and influences the outcomes of endotoxin-induced myocardial dysfunction. TSG101 transgenic and knockdown mice underwent endotoxin/lipopolysaccharide treatment (10 μg/g) and were assessed for survival, cardiac function, systemic/local inflammation, and activity of mitophagy mediators in the heart. Upon endotoxin challenge and compared with WT mice, TSG101 transgenic mice exhibited increased survival, preserved cardiac contractile function, reduced inflammation, and enhanced mitophagy activation in the heart. By contrast, TSG101 knockdown mice displayed opposite phenotypes during endotoxemia. Mechanistically, both coimmunoprecipitation assays and coimmunofluorescence staining revealed that TSG101 directly binds to Parkin in the cytosol of myocytes and facilitates translocation of Parkin from the cytosol to the mitochondria. Our results indicate that TSG101 elevation could protect against endotoxin-triggered myocardial injury by promoting Parkin-induced mitophagy.

H2 Protects Against Lipopolysaccharide-Induced Cardiac Dysfunction via Blocking TLR4-Mediated Cytokines Expression

Background and Purpose: Septic cardiomyopathy, which is one of the features of multi-organ dysfunction in sepsis, is characterized by ventricular dilatation, reduced ventricular contractility, and reduction in ejection fraction and, if severe, can lead to death. To date, there is no specific therapy that exists, and its treatment represents a large unmet clinical need. Herein, we investigated the effects and underlying anti-inflammatory mechanisms of hydrogen gas in the setting of lipopolysaccharide (LPS)-induced cardiomyocytes injury.

Experimental Approach: Hydrogen gas was intraperitoneally injected to mice in LPS plus hydrogen group and hydrogen group for 4 days. On fourth, LPS was given by intraperitoneal injection to mice in LPS group and to mice in LPS plus hydrogen group. In addition, H9c2 cardiomyocytes were treated with hydrogen-rich medium for 30 min before LPS. The transthoracic echocardiography was performed at 6 h post‐LPS to assess left ventricular end-systolic diameter (LVESD), left ventricular end-diastolic diameter (LVEDD), left ventricular ejection fraction (EF%), fractional shortening (FS%), left ventricular mass average weight (LV mass AW), and LV mass AW (Corrected). The histological and morphological analyses of left ventricular were performed by hematoxylin and eosin (H&E) staining and Masson’s trichrome staining. The mRNA levels of ANP and BNP were examined by PCR in vitro. The expression of cytokines were assayed by Enzyme Linked Immunosorbent Assay (ELISA) and PCR. Moreover, Western blotting was performed to examine the expression of TLR4, the activation of ERK1/2, p38, JNK, and the expression of NF-κB in nucleus after 6 h of LPS challenge in vivo and in vitro.

Key Results: LPS induced cardiac dysfunction; hydrogen therapy improved cardiac function after LPS challenge. Furthermore, pretreatment with hydrogen resulted in cardioprotection during septic cardiomyopathy via inhibiting the expression of pro-inflammatory cytokines TNFα, IL-1β, and IL-18; suppressing the phosphorylation of ERK1/2, p38, and JNK; and reducing the nuclear translocation of NF-κB and the expression of TLR4 by LPS.

Conclusion and Implications: Hydrogen therapy prevents LPS-induced cardiac dysfunction in part via downregulation of TLR4-mediated pro-inflammatory cytokines expression.