A comparison of etanercept vs. infliximab for the treatment of post-arrest myocardial dysfunction in a swine model of ventricular fibrillation

Gene-selective transcription promotes the inhibition of tissue reparative macrophages by TNF

Pro-inflammatory TNF is a highly gene-selective inhibitor of the gene expression program of tissue repair and wound healing macrophages.

Anti-TNF therapies are a core anti-inflammatory approach for chronic diseases such as rheumatoid arthritis and Crohn’s Disease. Previously, we and others found that TNF blocks the emergence and function of alternative-activated or M2 macrophages involved in wound healing and tissue-reparative functions. Conceivably, anti-TNF drugs could mediate their protective effects in part by an altered balance of macrophage activity. To understand the mechanistic basis of how TNF regulates tissue-reparative macrophages, we used RNAseq, scRNAseq, ATACseq, time-resolved phospho-proteomics, gene-specific approaches, metabolic analysis, and signaling pathway deconvolution. We found that TNF controls tissue-reparative macrophage gene expression in a highly gene-specific way, dependent on JNK signaling via the type 1 TNF receptor on specific populations of alternative-activated macrophages. We further determined that JNK signaling has a profound and broad effect on activated macrophage gene expression. Our findings suggest that TNF’s anti-M2 effects evolved to specifically modulate components of tissue and reparative M2 macrophages and TNF is therefore a context-specific modulator of M2 macrophages rather than a pan-M2 inhibitor.

Angiotensin (1-7) Alleviates Postresuscitation Myocardial Dysfunction by Suppressing Oxidative Stress Through the Phosphoinositide 3-Kinase, Protein Kinase B, and Endothelial Nitric Oxide Synthase Signaling Pathway

ABSTRACT

There is increasing evidence that angiotensin (1-7) [Ang (1-7)] is an endogenous biologically active component of the renin-angiotensin system. However, the role of the Ang (1-7)-MasR axis in postresuscitation myocardial dysfunction (PRMD) and its associated mechanism are still unclear. In this study, we investigated the effect of the Ang (1-7)-MasR axis on myocardial injury after cardiac arrest-cardiopulmonary resuscitation-restoration of spontaneous circulation. We established a model of oxygen/glucose deprivation-reperfusion in myocardial cells in vitro and a rat model of cardiac arrest-cardiopulmonary resuscitation-restoration of spontaneous circulation in vivo. The cell apoptosis rate and the expression of the superoxide anion 3-nitrotyrosine were decreased in the Ang (1-7) group in vitro and in vivo. The mean arterial pressure was decreased, whereas +LVdp/dtmax and -LVdp/dtmax were increased in rats in the Ang (1-7) group. The mRNA and protein levels of Ang II type 1 receptor, MasR, phosphoinositide 3-kinase, protein kinase B, and endothelial nitric oxide synthase were increased in the Ang (1-7) group in vivo. These results indicate that the Ang (1-7)-MasR axis can alleviate PRMD by reducing myocardial tissue damage and oxidative stress through activation of the phosphoinositide 3-kinase-protein kinase B-endothelial nitric oxide synthase signaling pathway and provide a new direction for the clinical treatment of PRMD.

The relationship between low survival and acute increase of tumor necrosis factor α expression in the lung in a rat model of asphyxial cardiac arrest

Cardiac arrest (CA) is sudden loss of heart function and abrupt stop in effective blood flow to the body. The patients who initially achieve return of spontaneous circulation (RoSC) after CA have low survival rate. It has been known that multiorgan dysfunctions after RoSC are associated with high morbidity and mortality. Most previous studies have focused on the heart and brain in RoSC after CA. Therefore, the aim of this research was to perform serological, physiological, and histopathology study in the lung and to determine whether or how pulmonary dysfunction is associated with low survival rate after CA. Experimental animals were divided into sham-operated group (n=14 at each point in time), which was not subjected to CA operation, and CA-operated group (n=14 at each point in time), which was subjected to CA. The rats in each group were sacrificed at 6 hours, 12 hours, 24 hours, and 2 days, respectively, after RoSC. Then, pathological changes of the lungs were analyzed by hematoxylin and eosin staining, Western blot and immunohistochemistry for tumor necrosis factor α (TNF-α). The survival rate after CA was decreased with time past. We found that histopathological score and TNF-α immunoreactivity were significantly increased in the lung after CA. These results indicate that inflammation triggered by ischemia-reperfusion damage after CA leads to pulmonary injury/dysfunctions and contributes to low survival rate. In addition, the finding of increase in TNF-α via inflammation in the lung after CA would be able to utilize therapeutic or diagnostic measures in the future.

Changes in histopathology and tumor necrosis factor-α levels in the hearts of rats following asphyxial cardiac arrest

OBJECTIVE

Post cardiac arrest (CA) syndrome is associated with a low survival rate in patients who initially have return of spontaneous circulation (ROSC) after CA. The aim of this study was to examine the histopathology and inflammatory response in the heart during the post CA syndrome.

METHODS

We induced asphyxial CA in male Sprague-Dawley rats and determined the survival rate of these rats during the post resuscitation phase.

RESULTS

Survival of the rats decreased after CA: 66.7% at 6 hours, 36.7% at 1 day, and 6.7% at 2 days after ROSC following CA. The rats were sacrificed at 6 hours, 12 hours, 1 day, and 2 days after ROSC, and their heart tissues were examined. Histopathological scores increased at 12 hours post CA and afterwards, histopathological changes were not significant. In addition, levels of tumor necrosis factor-α immunoreactivity gradually increased after CA.

CONCLUSION

The survival rate of rats 2 days post CA was very low, even though histopathological and inflammatory changes in the heart were not pronounced in the early stage following CA.

Neuronal injury and tumor necrosis factor-alpha immunoreactivity in the rat hippocampus in the early period of asphyxia-induced cardiac arrest under normothermia

Low survival rate occurs in patients who initially experience a spontaneous return of circulation after cardiac arrest (CA). In this study, we induced asphyxial CA in adult male Sprague-Daley rats, maintained their body temperature at 37 ± 0.5°C, and then observed the survival rate during the post-resuscitation phase. We examined neuronal damage in the hippocampus using cresyl violet (CV) and Fluore-Jade B (F-J B) staining, and pro-inflammatory response using ionized calcium-binding adapter molecule 1 (Iba-1), glial fibrillary acidic protein (GFAP), and tumor necrosis factor-alpha (TNF-α) immunohistochemistry in the hippocampus after asphyxial CA in rats under normothermia. Our results show that the survival rate decreased gradually post-CA (about 63% at 6 hours, 37% at 1 day, and 8% at 2 days post-CA). Rats were sacrificed at these points in time post-CA, and no neuronal damage was found in the hippocampus until 1 day post-CA. However, some neurons in the stratum pyramidale of the CA region in the hippocampus were dead 2 days post-CA. Iba-1 immunoreactive microglia in the CA1 region did not change until 1 day post-CA, and they were activated (enlarged cell bodies with short and thicken processes) in all layers 2 days post-CA. Meanwhile, GFAP-immunoreactive astrocytes did not change significantly until 2 days post-CA. TNF-α immunoreactivity decreased significantly in neurons of the stratum pyramidale in the CA1 region 6 hours post-CA, decreased gradually until 1 day post-CA, and increased significantly again 2 days post-CA. These findings suggest that low survival rate of normothermic rats in the early period of asphyxia-induced CA is related to increased TNF-α immunoreactivity, but not to neuronal damage in the hippocampal CA1 region.

Right ventricular dysfunction after resuscitation predicts poor outcomes in cardiac arrest patients independent of left ventricular function

OBJECTIVE

Determination of clinical outcomes following resuscitation from cardiac arrest remains elusive in the immediate post-arrest period. Echocardiographic assessment shortly after resuscitation has largely focused on left ventricular (LV) function. We aimed to determine whether post-arrest right ventricular (RV) dysfunction predicts worse survival and poor neurologic outcome in cardiac arrest patients, independent of LV dysfunction.

METHODS

A single-center, retrospective cohort study at a tertiary care university hospital participating in the Penn Alliance for Therapeutic Hypothermia (PATH) Registry between 2000 and 2012.

PATIENTS

291 in- and out-of-hospital adult cardiac arrest patients at the University of Pennsylvania who had return of spontaneous circulation (ROSC) and post-arrest echocardiograms.

MEASUREMENTS AND MAIN RESULTS

Of the 291 patients, 57% were male, with a mean age of 59 ± 16 years. 179 (63%) patients had LV dysfunction, 173 (59%) had RV dysfunction, and 124 (44%) had biventricular dysfunction on the initial post-arrest echocardiogram. Independent of LV function, RV dysfunction was predictive of worse survival (mild or moderate: OR 0.51, CI 0.26-0.99, p<0.05; severe: OR 0.19, CI 0.06-0.65, p=0.008) and neurologic outcome (mild or moderate: OR 0.33, CI 0.17-0.65, p=0.001; severe: OR 0.11, CI 0.02-0.50, p=0.005) compared to patients with normal RV function after cardiac arrest.

CONCLUSIONS

Echocardiographic findings of post-arrest RV dysfunction were equally prevalent as LV dysfunction. RV dysfunction was significantly predictive of worse outcomes in post-arrest patients after accounting for LV dysfunction. Post-arrest RV dysfunction may be useful for risk stratification and management in this high-mortality population.

Myocardial Dysfunction and Shock after Cardiac Arrest

Postarrest myocardial dysfunction includes the development of low cardiac output or ventricular systolic or diastolic dysfunction after cardiac arrest. Impaired left ventricular systolic function is reported in nearly two-thirds of patients resuscitated after cardiac arrest. Hypotension and shock requiring vasopressor support are similarly common after cardiac arrest. Whereas shock requiring vasopressor support is consistently associated with an adverse outcome after cardiac arrest, the association between myocardial dysfunction and outcomes is less clear. Myocardial dysfunction and shock after cardiac arrest develop as the result of preexisting cardiac pathology with multiple superimposed insults from resuscitation. The pathophysiology involves cardiovascular ischemia/reperfusion injury and cardiovascular toxicity from excessive levels of inflammatory cytokine activation and catecholamines, among other contributing factors. Similar mechanisms occur in myocardial dysfunction after cardiopulmonary bypass, in sepsis, and in stress-induced cardiomyopathy. Hemodynamic stabilization after resuscitation from cardiac arrest involves restoration of preload, vasopressors to support arterial pressure, and inotropic support if needed to reverse the effects of myocardial dysfunction and improve systemic perfusion. Further research is needed to define the role of postarrest myocardial dysfunction on cardiac arrest outcomes and identify therapeutic strategies.