Do interleukin-10 and superoxide ions predict outcomes of cardiac extracorporeal membrane oxygenation patients?

Mortality risk factors in patients receiving ECPR after cardiac arrest: Development and validation of a clinical prognostic prediction model

BACKGROUND

Previous studies have shown an increasing trend of extracorporeal cardiopulmonary resuscitation (ECPR) use in patients with cardiac arrest (CA). Although ECPR have been found to reduce mortality in patients with CA compared with conventional cardiopulmonary resuscitation (CCPR), the mortality remains high. This study was designed to identify the potential mortality risk factors for ECPR patients for further optimization of patient management and treatment selection.

METHODS

We conducted a prospective, multicentre study collecting 990 CA patients undergoing ECPR in 61 hospitals in China from January 2017 to May 2022 in CSECLS registry database. A clinical prediction model was developed using cox regression and validated with external data.

RESULTS

The data of 351 patients meeting the inclusion criteria before October 2021 was used to develop a prediction model and that of 68 patients after October 2021 for validation. Of the 351 patients with CA treated with ECPR, 227 (64.8%) patients died before hospital discharge. Multivariate analysis suggested that a medical history of cerebrovascular diseases, pulseless electrical activity (PEA)/asystole and higher Lactate (Lac) were risk factors for mortality while aged 45-60, higher pH and intra-aortic balloon pump (IABP) during ECPR have protective effects. Internal validation by bootstrap resampling was subsequently used to evaluate the stability of the model, showing moderate discrimination, especially in the early stage following ECPR, with a C statistic of 0.70 and adequate calibration with GOF chi-square = 10.4 (p = 0.50) for the entire cohort. Fair discrimination with c statistic of 0.65 and good calibration (GOF chi-square = 6.1, p = 0.809) in the external validation cohort demonstrating the model's ability to predict in-hospital death across a wide range of probabilities.

CONCLUSION

Risk factors have been identified among ECPR patients including a history of cerebrovascular diseases, higher Lac and presence of PEA or asystole. While factor such as age 45-60, higher pH and use of IABP have been found protective against in-hospital mortality. These factors can be used for risk prediction, thereby improving the management and treatment selection of patients for this resource-intensive therapy.

Inflammatory Progression in Patients Undergoing Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) is identified as a novel therapeutic strategy that offers short-term support to the metabolism of the heart and lungs in humans. Recently, the clinical centers, which provide ECMO has increased rapidly worldwide. The indications for the use of ECMO in daily clinical practice were broadened dynamically. However, even with the widespread adoption of ECMO, it still remains significant morbidity and mortality, and the underlying mechanisms are still not elucidated. Notably, one of the vital complications during ECMO was proposed as the inflammatory progression within the extracorporeal circulation. via the development of inflammatory response, patients with ECMO may further suffer from systemic inflammatory response syndrome (SIRS), posing serious risks to human health. Recently, growing evidence confirmed that through exposure of blood into the ECMO circuit could lead to the stimulation of the immune system which also facilitated the inflammatory response and systemic impaired. In the current review, the pathological development of inflammatory progression in patients with ECMO is well-listed. Furthermore, the relationship between immune-related activation and the development of inflammation is also summarized, which may further help us to decide the therapeutic strategies in daily clinical practice.

Prognostic models for mortality risk in patients requiring ECMO

PURPOSE

To provide an overview and evaluate the performance of mortality prediction models for patients requiring extracorporeal membrane oxygenation (ECMO) support for refractory cardiocirculatory or respiratory failure.

METHODS

A systematic literature search was undertaken to identify studies developing and/or validating multivariable prediction models for all-cause mortality in adults requiring or receiving veno-arterial (V-A) or veno-venous (V-V) ECMO. Estimates of model performance (observed versus expected (O:E) ratio and c-statistic) were summarized using random effects models and sources of heterogeneity were explored by means of meta-regression. Risk of bias was assessed using the Prediction model Risk Of BiAS Tool (PROBAST).

RESULTS

Among 4905 articles screened, 96 studies described a total of 58 models and 225 external validations. Out of all 58 models which were specifically developed for ECMO patients, 14 (24%) were ever externally validated. Discriminatory ability of frequently validated models developed for ECMO patients (i.e., SAVE and RESP score) was moderate on average (pooled c-statistics between 0.66 and 0.70), and comparable to general intensive care population-based models (pooled c-statistics varying between 0.66 and 0.69 for the Simplified Acute Physiology Score II (SAPS II), Acute Physiology and Chronic Health Evaluation II (APACHE II) score and Sequential Organ Failure Assessment (SOFA) score). Nearly all models tended to underestimate mortality with a pooled O:E > 1. There was a wide variability in reported performance measures of external validations, reflecting a large between-study heterogeneity. Only 1 of the 58 models met the generally accepted Prediction model Risk Of BiAS Tool criteria of good quality. Importantly, all predicted outcomes were conditional on the fact that ECMO support had already been initiated, thereby reducing their applicability for patient selection in clinical practice.

CONCLUSIONS

A large number of mortality prediction models have been developed for ECMO patients, yet only a minority has been externally validated. Furthermore, we observed only moderate predictive performance, large heterogeneity between-study populations and model performance, and poor methodological quality overall. Most importantly, current models are unsuitable to provide decision support for selecting individuals in whom initiation of ECMO would be most beneficial, as all models were developed in ECMO patients only and the decision to start ECMO had, therefore, already been made.

Multi-organ dysfunction syndrome in patients undergoing extracorporeal life support

BACKGROUND

Multiple organ failure is a common complication in patients undergoing ECLS significantly affecting patient outcomes. Gaining knowledge about the mechanisms of onset, clinical course, risk factors, and potential therapeutic targets is highly desirable.

METHODS

Data of 354 patients undergoing ECLS with one-, two, three-, and four organ failures were retrospectively analyzed. Incidence of multiple organ dysfunction (MODS), its impact on survival, risk factors for its occurrence, and the impact of proinflammatory mediators on the occurrence of MODS in patients undergoing ECLS were investigated.

RESULTS

The median follow-up was 66 (IQR 6; 820) days. 245 (69.2%) patients could be weaned from ECLS, 30-day survival and 1-year survival were 194 (54.1%) and 157 (44.4%), respectively. The duration of mechanical support was 4 (IQR 2; 7) days in the median. Increasing severity of MODS resulted in significant prolongation of mechanical circulatory support and worsening of the outcome. Liver dysfunction had the strongest impact on patient mortality (OR = 2.5) and survival time (19 vs 367 days). The serum concentration of analyzed interleukins rose significantly with each, additional organ affected by dysfunction (p < 0.001). All analyzed proinflammatory cytokines showed significant predictivity relative to the occurrence of MODS with interleukin 8 serum level prior to ECLS showing the strongest predictive potential for the occurrence of MODS (AUC 0.78).

CONCLUSION

MODS represents a frequent complication in patients undergoing ECLS with a significant impact on survival. Proinflammatory cytokines show prognostic capacity regarding the occurrence and severity of multi-organ dysfunction.

The Pulsatile Modification Improves Hemodynamics and Attenuates Inflammatory Responses in Extracorporeal Membrane Oxygenation

Background

COVID-19 is still a worldwide pandemic and extracorporeal membrane oxygenation (ECMO) is vital for extremely critical COVID-19 patients. Pulsatile flow impacts greatly on organ function and microcirculation, however, the effects of pulsatile flow on hemodynamics and inflammatory responses during ECMO are unknown. An in vivo study was launched aiming at comparing the two perfusion modes in ECMO.

Methods

Fourteen beagles were randomly allocated into two groups: the pulsatile group (n=7) and the non-pulsatile group (n=7). ECMO was conducted using the i-Cor system for 24 hours. Hemodynamic parameters including surplus hemodynamic energy (SHE), energy equivalent pressure (EEP), oxygenator pressure drop (OPD), and circuit pressure drop (CPD) were monitored. To assess inflammatory responses during ECMO, levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, IL-8, and transforming growth factor-β1 (TGF-β1) were measured.

Results

EEP and SHE were markedly higher in pulsatile circuits when compared with the conventional circuits. Between-group differences in both OPD and CPD reached statistical significance. Significant decreases in TNF-α were seen in animals treated with pulsatile flows at 2 hours, 12 hours, and 24 hours as well as a decrease in IL-1β at 24 hours during ECMO. The TGF-β1 levels were significantly higher in pulsatile circuits from 2 hours to 24 hours. The changes in IL-6 and IL-8 levels were insignificant.

Conclusion

The modification of pulsatility in ECMO generates more hemodynamic energies and attenuates inflammatory responses as compared to the conventional non-pulsatile ECMO.

Mesenchymal stem cells may ameliorate inflammation in an ex vivo model of extracorporeal membrane oxygenation

INTRODUCTION

Mesenchymal stem cells exhibit immunomodulatory properties which are currently being investigated as a novel treatment option for Acute Respiratory Distress Syndrome. However, the feasibility and efficacy of mesenchymal stem cell therapy in the setting of extracorporeal membrane oxygenation is poorly understood. This study aimed to characterise markers of innate immune activation in response to mesenchymal stem cells during an ex vivo simulation of extracorporeal membrane oxygenation.

METHODS

Ex vivo extracorporeal membrane oxygenation simulations (n = 10) were conducted using a commercial extracorporeal circuit with a CO₂-enhanced fresh gas supply and donor human whole blood. Heparinised circuits (n = 4) were injected with 40 × 10⁶-induced pluripotent stem cell-derived human mesenchymal stem cells, while the remainder (n = 6) acted as controls. Simulations were maintained, under physiological conditions, for 240 minutes. Circuits were sampled at 15, 30, 60, 120 and 240 minutes and assessed for levels of interleukin-1β, interleukin-6, interleukin-8, interleukin-10, tumour necrosis factor-α, transforming growth factor-β1, myeloperoxidase and α-Defensin-1. In addition, haemoglobin, platelet and leukocyte counts were performed.

RESULTS

There was a trend towards reduced levels of pro-inflammatory cytokines in mesenchymal stem cell-treated circuits and a significant increase in transforming growth factor-β1. Blood cells and markers of neutrophil activation were reduced in mesenchymal stem cell circuits during the length of the simulation. As previously reported, the addition of mesenchymal stem cells resulted in a reduction of flow and increased trans-oxygenator pressures in comparison to controls.

CONCLUSIONS

The addition of mesenchymal stem cells during extracorporeal membrane oxygenation may cause an increase in transforming growth factor-β1. This is despite their ability to adhere to the membrane oxygenator. Further studies are required to confirm these findings.

The Functional Immune Response of Patients on Extracorporeal Life Support

Extracorporeal life support (ECLS) is a widely used lifesaving technology. Whether ECLS results in immune dysregulation is unclear. This study's aim was to examine whether ECLS affected innate immune response. All patients placed on ECLS were eligible. Blood was obtained before, during, and after ECLS. Function of the innate immune system was measured by ex vivo lipopolysaccharide (LPS)-induced tumor necrosis factor-α (TNF-α) and plasma cytokine levels (interleukin [IL]-6, IL-8, IL-10, and TNF-α). Immunoparalysis was defined as ex vivo TNF-α levels less than 200 pg/ml. Nineteen patients were enrolled with twelve <18 years old. Median ECLS duration was 10 days (range: 3-108); nine patients died. After stratifying the cohort by the presence of immunoparalysis before ECLS, those immunoparalyzed showed increased response to LPS on days 1 and 3 (p = 0.016). Those without pre-ECLS immunoparalysis showed a transient decrease in response on day 3 (p = 0.008). Plasma IL-10 levels were elevated in those with pre-ECLS immunoparalysis and dropped significantly by day 1 (p = 0.031). The number treated with steroids was similar in the two groups. In conclusion, patients with immunoparalysis before ECLS showed a gradual increase in immune function during ECLS, whereas those without immunoparalysis had a transient decrease in responsiveness on day 3.

Klotho-beta and fibroblast growth factor 19 expression correlates with early recurrence of resectable hepatocellular carcinoma

BACKGROUND AND AIMS

Fibroblast growth factor 19 (FGF19) and fibroblast growth factor receptor 4 (FGFR4) signalling play critical roles in hepatocarcinogenesis. This study explored the potential of FGF19- and FGFR4-related biomarkers in predicting early tumour recurrence (ETR) and survival in patients with resectable hepatocellular carcinoma (HCC).

METHODS

We examined the mRNA expressions of FGF19, FGFR4, klotho-beta (KLB), cyclin D1 (CCND1) and FGF4 in 151 surgically resected, primary unifocal HCCs through quantitative real-time polymerase chain reaction. Generalized additive models were fitted to detect nonlinear effects of continuous covariates and define thresholds of biomarker expressions. Univariate and multivariate analyses were performed to evaluate prognostic values of these biomarkers for tumour recurrence and patient survival.

RESULTS

Overexpression of FGF19, FGFR4, KLB, CCND1 and FGF4 mRNA was detected in 40%, 32%, 26%, 15% and 35% of 151 tumours respectively. ETR was the strongest prognostic factor predicting worse overall survival (hazard ratio [HR], 5.678; 95% confidence interval, 3.7-8.713; P < 0.001). Furthermore, we revealed that mRNA expression levels of KLB (HR, 3.857; P = 0.021) and FGF19 (HR, 3.248; P = 0.017) were significantly associated with the occurrence of ETR.

CONCLUSIONS

Frequent overexpression of FGF19/FGFR4-related biomarkers was detected in resectable HCC. Expression levels of KLB and FGF19 may determine patient survival outcomes through their effects on ETR.

Calcium‑sensing receptors in human peripheral T lymphocytes and AMI: Cause and effect

Acute myocardial infarction (AMI) is a disease associated with inflammation. T lymphocytes are involved by secreting cytokines and inflammatory factors. In our previous study, it was found that the T lymphocytes exhibited certain functional changes, the onset of which was induced by modulating calcium‑sensing receptor (CaSR) in AMI. In the present study, western blotting was used to verified the expression of T lymphocyte CaSR and pathway proteins, including phosphorylated extracellular signal‑regulated kinase (P‑ERK)1/2 and phosphorylated c‑Jun N‑terminal kinase (P‑JNK), and used cytometric bead array to detect the secretion of interleukin (IL)‑4, IL‑6, IL‑10 and tumor necrosis factor (TNF)‑α in AMI onset, the results demonstrated that they were all increased. In addition, the expression of T lymphocyte pathway proteins, including P‑ERK1/2 and P‑JNK, and the secretion of IL‑4, IL‑6, IL‑10 and TNF‑α decreased after T lymphocytes being transfected by CaSR small interfering RNA. By contrast, the neonatal mouse cardiomyocytes under hypoxia and hypoxia/re‑oxygenation exhibited ultrastructural damage, increased apoptosis, increased production of lactate dehydrogenase (LDH) and malondialdehyde, and reduced superoxide dismutase; these indicators changed extensively when cardiomyocytes were co‑cultured with T lymphocytes. However, the effects were reversed when the cardiomyocytes were co‑cultured with CaSR‑silenced T lymphocytes. These results indicated that CaSR may modulate T lymphocytes to release cytokines through mitogen‑activated protein kinase pathways and affect cardiomyocyte injury. The relationship between AMI and T lymphocyte CaSR is reciprocal.

Early measurement of IL-10 predicts the outcomes of patients with acute respiratory distress syndrome receiving extracorporeal membrane oxygenation

Patients diagnosed with acute respiratory distress syndrome are generally severely distressed and associated with high morbidity and mortality despite aggressive treatments such as extracorporeal membrane oxygenation (ECMO) support. To identify potential biomarker of predicting value for appropriate use of this intensive care resource, plasma interleukin-10 along with relevant inflammatory cytokines and immune cell populations were examined during the early and subsequent disease courses of 51 critically ill patients who received ECMO support. High interleukin-10 levels at the time of ECMO installation and during the first 6 hours after ECMO support of these patients stand as a promising biomarker associated with grave prognosis. The initial interleukin-10 level is correlated to other conventional risk evaluation scores as a predictive factor for survival, and furthermore, elevated interleukin-10 levels are also related to a delayed recovery of certain immune cell populations such as CD14⁺CD16⁺, CD14⁺TLR4⁺ monocytes, and T regulator cells. Genetically, high interleukin-10 is associated to two polymorphic nucleotides (−592 C and −819 C) at the interleukin-10 gene promoter area. Our finding provides prognostic and mechanistic information on the outcome of severely respiratory distressed patients, and potentially paves the strategy to develop new therapeutic modality based on the principles of precision medicine.

The inflammatory response to extracorporeal membrane oxygenation (ECMO): a review of the pathophysiology

Extracorporeal membrane oxygenation (ECMO) is a technology capable of providing short-term mechanical support to the heart, lungs or both. Over the last decade, the number of centres offering ECMO has grown rapidly. At the same time, the indications for its use have also been broadened. In part, this trend has been supported by advances in circuit design and in cannulation techniques. Despite the widespread adoption of extracorporeal life support techniques, the use of ECMO remains associated with significant morbidity and mortality. A complication witnessed during ECMO is the inflammatory response to extracorporeal circulation. This reaction shares similarities with the systemic inflammatory response syndrome (SIRS) and has been well-documented in relation to cardiopulmonary bypass. The exposure of a patient’s blood to the non-endothelialised surface of the ECMO circuit results in the widespread activation of the innate immune system; if unchecked this may result in inflammation and organ injury. Here, we review the pathophysiology of the inflammatory response to ECMO, highlighting the complex interactions between arms of the innate immune response, the endothelium and coagulation. An understanding of the processes involved may guide the design of therapies and strategies aimed at ameliorating inflammation during ECMO. Likewise, an appreciation of the potentially deleterious inflammatory effects of ECMO may assist those weighing the risks and benefits of therapy.