Induction and deduction in sepsis-induced cardiomyopathy: five typical categories

Assessment of Pulmonary Circulation of Critically Ill Patients Based on Critical Care Ultrasound

Pulmonary circulation is crucial in the human circulatory system, facilitating the oxygenation of blood as it moves from the right heart to the lungs and then to the left heart. However, during critical illness, pulmonary microcirculation can be vulnerable to both intrapulmonary and extrapulmonary injuries. To assess these potential injuries in critically ill patients, critical point-of-care ultrasound can be used to quantitatively and qualitatively evaluate the right atrium, right ventricle, pulmonary artery, lung, pulmonary vein, and left atrium along the direction of blood flow. This assessment is particularly valuable for common ICU diseases such as acute respiratory distress syndrome (ARDS), sepsis, pulmonary hypertension, and cardiogenic pulmonary edema. It has significant potential for diagnosing and treating these conditions in critical care medicine.

Identification of key genes in sepsis-induced cardiomyopathy based on integrated bioinformatical analysis and experiments in vitro and in vivo

Introduction

Sepsis is a life-threatening disease that damages multiple organs and induced by the host's dysregulated response to infection with high morbidity and mortality. Heart remains one of the most vulnerable targets of sepsis-induced organ damage, and sepsis-induced cardiomyopathy (SIC) is an important factor that exacerbates the death of patients. However, the underlying genetic mechanism of SIC disease needs further research.

Methods

The transcriptomic dataset, GSE171564, was downloaded from NCBI for further analysis. Gene expression matrices for the sample group were obtained by quartile standardization and log2 logarithm conversion prior to analysis. The time series, protein-protein interaction (PPI) network, and functional enrichment analysis via Gene Ontology and KEGG Pathway Databases were used to identify key gene clusters and their potential interactions. Predicted miRNA-mRNA relationships from multiple databases facilitated the construction of a TF-miRNA-mRNA regulatory network. In vivo experiments, along with qPCR and western blot assays, provided experimental validation.

Results

The transcriptome data analysis between SIC and healthy samples revealed 221 down-regulated, and 342 up-regulated expressed genes across two distinct clusters. Among these, Tpt1, Mmp9 and Fth1 were of particular significance. Functional analysis revealed their role in several biological processes and pathways, subsequently, in vivo experiments confirmed their overexpression in SIC samples. Notably, we found TPT1 play a pivotal role in the progression of SIC, and silencing TPT1 showed a protective effect against LPS-induced SIC.

Conclusion

In our study, we demonstrated that Tpt1, Mmp9 and Fth1 have great potential to be biomarker of SIC. These findings will facilitated to understand the occurrence and development mechanism of SIC.

Xuebijing injection protects sepsis induced myocardial injury by mediating TLR4/NF-κB/IKKα and JAK2/STAT3 signaling pathways

OBJECTIVE

Compelling evidence has demonstrated that Xuebijing (XBJ) exerted protective effects against SIMI. The aims of this study were to investigate whether TLR4/IKKα-mediated NF-κB and JAK2/STAT3 pathways were involved in XBJ's cardio-protection during sepsis and the mechanisms.

METHODS

In this study, rats were randomly assigned to three groups: Sham group; CLP group; XBJ group. Rats were treated with XBJ or sanitary saline after CLP. Echocardiography, myocardial enzymes and HE were used to detect cardiac function. IL-1β, IL-6 and TNF-α in serum were measured using ELISA kits. Cardiomyocyte apoptosis were tested by TUNEL staining. The protein levels of Bax, Bcl-2, Bcl-xl, Cleaved-Caspase 3, Cleaved-Caspase 9, Cleaved-PARP, TLR4, p-NF-κB, p-IKKα, p-JAK2 and p-STAT3 in the myocardium were assayed by western blotting. And finally, immunofluorescence was used to assess the level of p-JAK2 and p-STAT3 in heart tissue.

RESULTS

The results of echocardiography, myocardial enzyme and HE test showed that XBJ could significantly improve SIMI. The IL-1β, IL-6 and TNF-α levels in the serum were markedly lower in the XBJ group than in the CLP group (p<0.05). TUNEL staining's results showed that XBJ ameliorated CLP-induced cardiomyocyte apoptosis. Meanwhile, XBJ downregulated the protein levels of Bax, Cleaved-Caspase 3, Cleaved-Caspase 9, Cleaved-PARP, TLR4, p-NF-κB, p-IKKα, p-JAK2 and p-STAT3, as well as upregulated the protein levels of Bcl-2, Bcl-xl (p <0.05).

CONCLUSIONS

In here, we observed that XBJ's cardioprotective advantages may be attributable to its ability to suppress inflammation and apoptosis via inhibiting the TLR4/ IKKα-mediated NF-κB and JAK2/STAT3 pathways during sepsis.

The protective effects of sophocarpine on sepsis-induced cardiomyopathy

This investigation elucidates the impact of sophocarpine treatment on lipopolysaccharide (LPS) stimulated sepsis-induced cardiomyopathy (SIC) via in vivo and in vitro experiments. Echocardiography, ELISA, TUNEL, Western blotting experiments, and Hematoxylin/Eosin, Dihydroethidium, and Immunohistochemistry staining assays, were carried out to identify associated indicators. The echocardiography revealed that sophocarpine treatment alleviated LPS-induced cardiac dysfunction as indicated by fractional shortening shortened and improved ejection fraction. Heart injury biomarkers, such as creatine kinase, lactate dehydrogenase, and creatine kinase-MB, were assessed, and indicated that sophocarpine treatment could alleviate LPS-induced upregulation of these indices. Furthermore, different experimental protocols revealed that sophocarpine treatment inhibits LPS-induced pathological alterations and decreases LPS-stimulated inflammatory cytokines, IL-1β, monocyte chemoattractant protein-1, IL-6, NOD-like receptor protein-3, and TNF-α, increase. Apoptotic proteins such as cytochrome-c, Bax, and cleaved-caspase-3 were increased, and Bcl-2 was alleviated after LPS stimulation; however, these effects were inhibited by sophocarpine treatment. Decreased antioxidant proteins [superoxide dismutase-1 (SOD-1) and SOD-2] induced by LPS stimulation were upregulated by sophocarpine treatment. LPS upregulated autophagic proteins such as Beclin-1 and the ratio of microtubule-associated protein 1A/1B-light chain 3 (LC3)-II/LC3-I and downregulated sequestosome 1 (SQSTM1, or P62), sophocarpine therapy reversed these effects. Moreover, it was indicated that sophocarpine treatment inhibited the Toll-like receptor-4 (TLR-4)/nuclear transcription factor-kappa B (NF-κB) signaling pathway and activated nuclear factor erythroid 2-related factor-2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway. In conclusion, sophocarpine treatment could alleviate LPS-trigger SIC by repressing oxidative stress, autophagy, inflammation, and apoptosis via TLR-4/NF-κB inhibition and Nrf2/HO-1 signaling pathway activation, implicating the potential of sophocarpine as a new therapeutic approach against SIC.

N-terminal Pro-B-Type Natriuretic Peptide is a Myocardial Biomarker in Pulmonary Sepsis and Septic Shock

The objective: to study changes and prognostic significance of the blood NT-proBNP in the patients with pulmonary sepsis.

Subjects and Methods. The study included 34 patients aged 54.5 ± 2.9 years with pulmonary sepsis or septic shock. Lethality in the intensive care unit (ICU) was 47.1%. NT-proBNP, procalcitonin (PCT) levels, blood lactate and hemodynamic parameters were registered on the 1st day (stage 1) and on the 4th-5th day of the ICU stay (stage 2). Hemodynamics was assessed through transpulmonary thermodilution. The differences were considered statistically significant at p < 0.05.

Results: At stage 1, NT-proBNP level was 5,220 [1,380‒17,850] pg/ml, did not decrease (p = 0.726) at stage 2 and amounted to 1,760 [631‒847] pg/ml. At stage 1, NT-proBNP correlated with extravascular lung water index (rho = 0.445; p = 0.038) and systolic pulmonary artery pressure (rho = 0.414; p = 0.023). At stage 2, NT-proBNP correlated with PCT (rho = 0.569; p = 0.003), blood lactate (rho = 0.525; p = 0.001), and mean arterial pressure to norepinephrine dosage ratio (rho = -0.422; p = 0.035). At stage 1, NT-proBNP was no predictor of lethality in the ICU: OR 1.0000; 95% CI 1.0000-1.0001. At stage 2, NT-proBNP > 4,260 pg/ml (sensitivity 87.5%, specificity 94.4%) was a predictor of lethality: OR 1.0004, 95% CI 1.0000-1.0008, p = 0.046 (AUC 0.893, 95% CI 0.732-0.974). Any increase of NT-proBNP level (> 0 pg/ml) between stages 2 and 1 was a predictor of lethality (sensitivity 87.5%, specificity 94.4%): OR 119.0, 95% CI 9.7432‒1,453.4241, p = 0.0002 (AUC 0.903, 95% CI 0.751-0.977).

Conclusion: Patients with pulmonary sepsis are characterized by a significant increase of blood NT-proBNP. At stage 1, the biomarker correlated with pulmonary hypertension and moderate pulmonary edema and was no predictor of lethality. At stage 2, NT-proBNP correlated with the indices of infection and sepsis severity (procalcitonin, blood lactate, and mean arterial blood pressure/norepinephrine dosage ratio). At this stage, NT-proBNP levels greater than 4,000 pg/mL and/or any degree of increase in blood levels of the biomarker were both sensitive and specific predictors of a lethal outcome. Specific features of etiopathogenesis of BNP hyperproduction in pulmonary sepsis make it difficult to interpret the elevation of NT-proBNP as an indicator of septic cardiomyopathy but does not reduce its value as a sensitive and specific predictor of lethality.

TMEM43 Protects against Sepsis-Induced Cardiac Injury via Inhibiting Ferroptosis in Mice

A previous study found that transmembrane protein 43 (TMEM43) was highly associated with arrhythmogenic right ventricular dysplasia/cardiomyopathy. However, as a transmembrane protein, TMEM43 may be involved in ferroptosis in cardiovascular disease. In this study, we aimed to explore the role of TMEM43 in lipopolysaccharide (LPS)-induced cardiac injury and the underlying mechanism. Mice were injected with LPS (10 mg/kg) for 12 h to generate experimental sepsis. Mice were also subjected to AAV9-shTMEM43 to knock down TMEM43 or AAV9-TMEM43 to overexpress TMEM43 in hearts. H9c2 rat cardiomyocytes were also transfected with Ad-TMEM43 or TMEM43 siRNA to overexpress/knock down TMEM43. As a result, TMEM43 knockdown in hearts deteriorated LPS-induced mouse cardiac injury and dysfunction. LPS increased cardiac ferroptosis as assessed by malonaldehyde (MDA) and cardiac iron density, which were aggravated by TMEM43 knockdown. Moreover, TMEM43 overexpression alleviated LPS-induced cardiac injury, dysfunction, and ferroptosis. In vitro experiments showed that TMEM43 overexpression inhibited LPS-induced lipid peroxidation and cardiomyocyte injury while TMEM43 knockdown aggravated LPS-induced ferroptosis and injury in cardiomyocytes. Mechanistically, LPS increased the expression of P53 and ferritin but decreased the level of Gpx4 and SLC7A11. TMEM43 could inhibit the level of P53 and ferritin enhanced the level of Gpx4 and SLC7A11. Furthermore, ferrostatin-1 (Fer-1), a specific inhibitor of ferroptosis, could protect against LPS-induced cardiac injury and also counteracted the deteriorating effects of TMEM43 silencing in the heart. Based on these findings, we concluded that TMEM43 protects against sepsis-induced cardiac injury via inhibiting ferroptosis in mice. By targeting ferroptosis in cardiomyocytes, TMEM43 may be a therapeutic strategy for preventing sepsis in the future.

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.

Construction of a predictive model and prognosis of left ventricular systolic dysfunction in patients with sepsis based on the diagnosis using left ventricular global longitudinal strain

BACKGROUND

Cardiac dysfunction, a common complication of sepsis, is associated with increased mortality. However, its risk factors are poorly understood, and a predictive model might help in the management of cardiac dysfunction.

METHODS

A monocentric prospective study of patients with sepsis was performed. Left ventricular global longitudinal strain (LV GLS) was measured using echocardiography within 72 h of the patients diagnosed with sepsis, and the patients were categorized into two groups: LV GLS > -17%, left ventricular systolic dysfunction group (LVSD group); and LV GLS ≤ -17%, non-left ventricular systolic dysfunction group (Non-LVSD group). The baseline characteristics and prognosis of the two groups were analyzed. Based on the results of the multivariate logistic regression analysis, a predictive model of LVSD was established and a nomogram was drawn.

RESULTS

Fifty-one left ventricular systolic dysfunction in patients with sepsis and 73 non-LVSD sepsis patients were included. Prognostic analysis showed that patients with LVSD had higher ICU mortality, in-hospital mortality, the incidence of atrial fibrillation (P < 0.05), and risk of death (HR = 3.104, 95% CI = 1.617-5.957, P < 0.001) compared to patients with non-LVSD. There were no significant differences in the rate of tracheal intubation, the incidence of acute kidney injury (AKI), the proportion of continuous renal replacement therapy (CRRT), length of ICU stay, and length of hospital stay between the 2 groups (P > 0.05). High sensitive troponin I (Hs-TnI) ≥ 0.131 ng/ml, procalcitonin (PCT) ≥ 40 ng/ml, lactate (Lac) ≥ 4.2 mmol/L, and N-terminal pro-brain natriuretic peptide (NT-proBNP) ≥ 3270 pg/ml were found to be the best cut-off values for the prediction of LVSD.

CONCLUSION

Sepsis patients with left ventricular systolic dysfunction had a higher risk of death and atrial fibrillation. Hs-TnI, PCT, Lac, and NT-proBNP were independent risk factors of LVSD, and the LVSD predictive model constructed using these factors showed good diagnostic performance.

TRIAL REGISTRATION

Chinese Clinical Trial Registry No: ChiCTR2000032128. Registered on 20 April 2020, http://www.chictr.org.cn/showproj.aspx ?proj=52531.

Berberine attenuates sepsis‑induced cardiac dysfunction by upregulating the Akt/eNOS pathway in mice

The present study aimed to investigate the cardioprotective role of berberine in sepsis-induced cardiac dysfunction and consider the underlying mechanisms. C57BL/6J mice were randomized into four groups, namely, Control, lipopolysaccharide (LPS), LPS + berberine and LPS + N^ω-nitro-L-arginine methyl ester (L-NAME) + berberine. A single dose (10 mg/kg body weight) of LPS was intraperitoneally administered to mice to induce cardiac dysfunction, whereas the Control group was administered with an equivalent volume of saline. In the LPS + berberine and LPS + L-NAME + berberine group, berberine (10 mg/kg body weight) dissolved in hot water was intraperitoneally administered 30 min after the LPS treatment. In the LPS + L-NAME + berberine group, L-NAME (100 mg/kg body weight) dissolved in saline was intraperitoneally administered 30 min before the LPS treatment. Then, ~6 h after the LPS treatment, a significant decrease was observed in the left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS). Meanwhile, the plasma myocardial injury markers, inflammatory factors and oxidative stress levels were significantly increased in the LPS group compared with the Control group. The administration of berberine improved the ventricular function and decreased the plasma myocardial injury markers, inflammatory factors and oxidative stress levels. In addition, it increased the heart total nitric oxide synthase (NOS) activity and upregulated the protein expressions of p-Akt and phosphorylated endothelial (e)NOS, which indicated that the Akt/eNOS pathway was activated by berberine. However, the cardioprotective effects of berberine were counteracted by L-NAME, an NOS inhibitor, which inhibited the eNOS activity. In conclusion, berberine attenuated sepsis-induced cardiac dysfunction by upregulating the Akt/eNOS pathway in mice.

Recombinant Activated Protein C (rhAPC) Affects Lipopolysaccharide-Induced Mechanical Compliance Changes and Beat Frequency of mESC-Derived Cardiomyocyte Monolayers

BACKGROUND

Septic cardiomyopathy increases mortality by 70% to 90% and results in mechanical dysfunction of cells.

METHODS

Here, we created a LPS-induced in-vitro sepsis model with mouse embryonic stem cell-derived cardiomyocytes (mESC-CM) using the CellDrum technology which simultaneously measures mechanical compliance and beat frequency of mESCs. Visualization of reactive oxygen species (ROS), actin stress fibers, and mRNA quantification of endothelial protein C receptor (EPCR) and protease-activated receptor 1 (PAR1) before/after LPS incubation were used for method validation. Since activated protein C (APC) has cardioprotective effects, samples were treated with human recombinant APC (rhAPC) with/-out LPS predamage to demonstrate the application in therapeutic studies.

RESULTS

Twelve hours LPS treatment (5 μg/mL) increased ROS and decreased actin stress fiber density and significantly downregulated EPCR and PAR1 compared to control samples (0.26, 0.39-fold respectively). rhAPC application (5 μg/mL, 12 h) decreased ROS and recovered actin density, EPCR, and PAR1 levels were significantly upregulated compared to LPS predamaged samples (4.79, 3.49-fold respectively). The beat frequencies were significantly decreased after 6- (86%) and 12 h (73%) of LPS application. Mechanical compliance of monolayers significantly increased in a time-dependent manner, up to eight times upon 12-h LPS incubation compared to controls. rhAPC incubation increased the beat frequency by 127% (6h-LPS) and 123% (12h-LPS) and decreased mechanical compliance by 68% (12h-LPS) compared to LPS predamaged samples.

CONCLUSION

LPS-induced contraction dysfunction and the reversal effects of rhAPC were successfully assessed by the mechanical properties of mESC-CMs. The CellDrum technology proved a decent tool to simulate sepsis in-vitro.

Speckle Tracking Algorithm-Based Ultrasonic Cardiogram in Evaluation of the Efficacy of Dexmedetomidine Combined with Bundle Strategy on Patients with Severe Sepsis

The research aimed to study the effect of dexmedetomidine combined with bundle strategy on the cardiac function of patients with severe sepsis through pyramid speckle tracking algorithm-based echocardiography, expected to provide reference for its clinical treatment. 98 patients with severe sepsis or septic shock admitted to the hospital were selected as the research subjects, and they were equally divided into experimental group (dexmedetomidine + bundle strategy) and control group (dexmedetomidine + routine nursing), with 49 in each. Ultrasonic cardiogram examination was performed on patients before and after treatment, and the pyramid-based speckle tracking (PST) algorithm was designed and used. The results showed that the running time of the PST algorithm (105.25 s) was less than that of the BM algorithm (336.41 s), and the difference was statistically significant (P < 0.05), and the systolic blood pressure, diastolic blood pressure, left ventricular wall, and heart rate of the experimental group before treatment were not significantly different from those of the control group (P > 0.05). The ultrasound index results found that the ejection fraction (EF) and fractional shortening (FS) of the two groups of patients showed a downward trend over time (1-7 days), while the E/A ratio showed an upward trend, and the E/A ratio of the experimental group was significantly greater than the control group (P < 0.05). The systolic blood pressure, diastolic blood pressure, left ventricular wall, and heart rate of the two groups of patients showed a downward trend over time (1-7 days), and the systolic blood pressure, diastolic blood pressure, left ventricular wall, and heart rate of the experimental group were significantly lower than those of the control group (P < 0.05). The 28-day mechanical ventilation time (6.97 ± 3.11 days), intensive care unit (ICU) stay time (9.18 ± 2.86 days), and the 28-day mortality rate (15.31%) of the experimental group were lower than those of the control group (6.97 ± 3.11 days; 13.08 ± 2.53 days; 31.95%) (P < 0.05). In conclusion, the PST algorithm can effectively improve the quality of echocardiography and assist physicians in clinical evaluation, and dexmedetomidine combined with bundle strategy can stabilize the heart rate and reduce myocardial oxygen consumption in severe sepsis, while effectively shortens the recovery time and improves the overall prognosis.