Ulinastatin improved cardiac dysfunction after cardiac arrest in New Zealand rabbits

The ACE2/Ang-(1-7)/MasR axis alleviates brain injury after cardiopulmonary resuscitation in rabbits by activating PI3K/Akt signaling

Background

Death among resuscitated patients is mainly caused by brain injury after cardiac arrest/cardiopulmonary resuscitation (CA/CPR). The angiotensin converting enzyme 2 (ACE2)/angiotensin (Ang)-(1-7)/Mas receptor (MasR) axis has beneficial effects on brain injury. Therefore, we examined the roles of the ACE2/Ang-(1-7)/MasR axis in brain injury after CA/CPR.

Method

We used a total of 76 male New Zealand rabbits, among which 10 rabbits underwent sham operation and 66 rabbits received CA/CPR. Neurological functions were determined by assessing serum levels of neuron-specific enolase and S100 calcium-binding protein B and neurological deficit scores. Brain water content was estimated. Neuronal apoptosis in the hippocampus was assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling assays. The expression levels of various genes were measured by enzyme-linked immunosorbent assay and western blotting.

Results

Ang-(1-7) (MasR activator) alleviated CA/CPR-induced neurological deficits, brain edema, and neuronal damage, and A779 (MasR antagonist) had the opposite functions. The stimulation of ACE2/Ang-(1-7)/MasR inactivated the ACE/Ang II/AT1R axis and activated PI3K/Akt signaling. Inhibiting PI3K/Akt signaling inhibited Ang-(1-7)-mediated protection against brain damage after CA/CPR.

Conclusion

Collectively, the ACE2/Ang-(1-7)/MasR axis alleviates CA/CPR-induced brain injury through attenuating hippocampal neuronal apoptosis by activating PI3K/Akt signaling.

Ulinastatin protects against sepsis‑induced myocardial injury by inhibiting NLRP3 inflammasome activation

Myocardial injury is the primary manifestation of multiple organ dysfunction during sepsis, however, the mechanisms underlying sepsis-induced myocardial injury remain unclear. Similarly, no effective therapeutics have yet been developed for myocardial injury. In the present study, the role of the NOD-like receptor 3 (NLRP3) inflammasome on cardiac function were characterized and the effects of different ulinastatin (UTI) doses in protecting a septic rat model from myocardial injury were elucidated. To evaluate UTI efficacy on cardiac function, its effects on anti-inflammatory mediators were analyzed and its cardioprotective effects were investigated. It was demonstrated that circulatory levels of tumor necrosis factor-α and interleukin-1β were elevated during sepsis. It was also observed that NLRP3 and caspase-1 expression enhanced post-cecal ligation and puncture (CLP), and that high UTI levels protected against myocardial injury induced by sepsis. To the best of our knowledge, this is the first study to demonstrate that the mechanisms underpinning UTI-mediated myocardial protection were due to the downregulation of the NLRP3/caspase-1/IL-1β signaling pathway. Based on these findings, it is proposed that UTI exerts beneficial effects during sepsis-induced myocardial injury.

Pre-arrest hypothermia improved cardiac function of rats by ameliorating the myocardial mitochondrial injury after cardiac arrest

This study investigated the effects of hypothermia induced before cardiac arrest or after return of spontaneous circulation (ROSC) on cardiac function and myocardial mitochondrial injury after ROSC in a rat cardiac arrest model. Sixty healthy, male Wistar rats were randomly divided into the Normothermia group, pre-arrest hypothermia (Pre-HT) group, and post-resuscitation hypothermia (Post-HT) group. The rats underwent 8 min of untreated ventricular fibrillation followed by cardiopulmonary resuscitation. Twelve rats in each group were used to evaluate the left ventricular ejection fraction before ventricular fibrillation and 4 h after ROSC. Survival was determined at 24 h after ROSC. The remaining eight rats in each group were used to detect for heart malondialdehyde, reduced glutathione, adenosine triphosphate levels and mitochondrial histology. Oxygen consumption rate and mitochondrial membrane potential were evaluated 4 h after ROSC; 10 of 12 rats in Pre-HT group, 5 of 12 in Post-HT group, and 6 of 12 in normothermia group were successfully resuscitated. The survival rate of each group was 66.7%, 33.3%, and 25%, respectively. Rats in the Pre-HT group showed less alteration of the mitochondrial ultrastructure and oxidative stress injury, better maintenance of adenine nucleotides, and more preservation of the mitochondrial membrane potential and respiratory function when compared with rats in the Post-HT and normothermia groups. Transient hypothermia is an effective preconditioning stimulus to induce ischemic tolerance in a cardiac arrest model and worthy of further evaluation for potential clinical use.

Impact statement

In this paper, we investigated the effects of hypothermia induced before ischemia or after ROSC on cardiac function, oxidative stress damage, and myocardial mitochondrial ischemia–reperfusion injury after cardiac arrest in a rat model with VF. We demonstrated that pre-arrest hypothermia conferred greater cardio-protective benefits than delayed post-resuscitation hypothermia, reduced the number of defibrillations required and dosages of epinephrine during CPR, decreased oxidative stress, ameliorated mitochondrial dysfunction, and subsequently improved survival rate.

Ulinastatin Protects against CVB3-Induced Acute Viral Myocarditis through Nrf2 Activation

Inflammation and oxidative stress are implicated in the pathogenesis of acute viral myocarditis (AVM). Ulinastantin (UTI), an inhibitor of serine protease widely used in treatment of pancreatitis and various inflammatory disorders, displays cardioprotective properties in experimental animals. Although the specific mechanism through which UTI regulates cardiac function is not well explored, evidence suggests that UTI might activate nuclear factor E2-related factor 2 (Nrf2) signaling. In this study, we investigated the role of Nrf2 in mediating UTI's cardioprotection in a mouse model of AVM. We found that UTI is an activator of Nrf2 signaling. It markedly increased Nrf2 nuclear translocation, Nrf2 transcription capacity, and the downstream protein expression. In addition, UTI possessed strong protective functions in coxsackievirus B3 (CVB3)-induced AVM. UTI treatment effectively reduced the cardiac damage, decreased the expression of inflammatory cytokines, and balanced oxidative stress via improving the activity of anti-oxidant and detoxifying enzymes. Even more impressively, UTI achieved its cardioprotective activities in an Nrf2-dependent manner. Taken together, our study has identified a novel pathway through which UTI exerts its cardioprotective functions and provides a molecular basis for UTI potential applications in the treatment of AVM and other inflammatory disorders.

Ulinastatin attenuates diabetes-induced cardiac dysfunction by the inhibition of inflammation and apoptosis

Ulinastatin exhibits anti-inflammatory activity and protects the heart from ischemia/reperfusion injury. However, whether ulinastatin has a protective effect in diabetic cardiomyopathy is yet to be elucidated. The aim of the present study was to investigate the protective effects of ulinastatin against diabetic cardiomyopathy and its underlying mechanisms. A C57/BL6J mice model of diabetic cardiomyopathy was used and mice were randomly assigned to three groups: Control group, diabetes mellitus (DM) group and DM + ulinastatin treatment group. Cardiac function was assessed using echocardiography and the level of inflammatory cytokine high mobility group box 1 (HMGB1) expression was measured using histopathological examination and reverse transcription-quantitative polymerase chain reaction. The levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 were measured using western blotting and ELISA. The apoptosis rate in the myocardium was assessed by TUNEL assay. Caspase-3 activation, expression of B-cell lymphoma 2 (Bcl-2) and Bcl-2 associated × (Bax) were measured using western blotting, as was the activity of the mitogen activated protein kinase (MAPK) signaling pathway. The results indicated that ulinastatin significantly improved cardiac function in mice with DM. Ulinastatin treatment significantly downregulated HMGB1, TNF-α and IL-6 expression (P<0.05) and significantly reduced the percentage of apoptotic cardiomyocytes (P<0.05) via reduction of caspase-3 activation and the ratio of Bax/Bcl-2 in diabetic hearts (P<0.05). In addition, ulinastatin attenuated the activation of the MAPK signaling pathway. In conclusion, ulinastatin had a protective effect against DM-induced cardiac dysfunction in a mouse model. This protective effect may be associated with the anti-inflammatory and anti-apoptotic abilities of ulinastatin via the MAPK signaling pathway.

Prearrest hypothermia improved defibrillation and cardiac function in a rabbit ventricular fibrillation model

BACKGROUND

Hypothermia when cardiopulmonary resuscitation begins may help achieve defibrillation and return of spontaneous circulation (ROSC), but few data are available.

OBJECTIVE

The objective of this study was to determine whether prearrest hypothermia improved defibrillation and cardiac function in a rabbit ventricular fibrillation (VF) model.

RESULTS

Thirty-six New Zealand rabbits were randomized equally to receive normothermia (Norm) (~39°C), post-ROSC hypothermia (~33°C), or prearrest hypothermia (~33°C). Ventricular fibrillation was induced by alternating current. After 4 minutes of VF, rabbits were defibrillated and given cardiopulmonary resuscitation until ROSC or no response (≥30 minutes). Hemodynamics and electrocardiogram were monitored; N-terminal pro-brain natriuretic peptideand troponin I were determined by enzyme-linked immunosorbent assay. Myocardial histology and echocardiographic data were evaluated. First-shock achievement of perfusion rhythm was more frequent in prearrest than normothermic animals (7/12 vs 1/12; P=.027). After ROSC, dp/dtmax was higher in prearrest than normothermic animals (P<.001). Left ventricular end-systolic pressure was higher in prearrest than normothermic animals (P=.001). At 240 minutes after ROSC, troponin I and N-terminal pro-brain natriuretic peptide were lower in prearrest than normothermic animals (15.74±2.26 vs 25.09±1.85 ng/mL and 426±23 vs 284±45 pg/mL, respectively), the left ventricular ejection fraction and cardiac output were lower in the Norm group than other 2 groups (P<.01). Myocardial histology was more disturbed in normothermic than post-ROSC and prearrest animals, but was not different in the latter 2 groups.

CONCLUSIONS

Induction of hypothermia before VF led to improved cardiac function in a rabbit VF model through improving achievement of perfusing rhythm by first-shock defibrillation and facilitating resuscitation.

The effects of α- and β-adrenergic blocking agents on postresuscitation myocardial dysfunction and myocardial tissue injury in a rat model of cardiac arrest

We investigated the relationship between the severity of postresuscitation (PR) myocardial tissue injury and myocardial dysfunction after the administration of epinephrine as well as the protective effects of α- and β-adrenergic blocking agents. Forty male Sprague-Dawley rats were randomized into 6 groups: (1) placebo; (2) epinephrine; (3) epinephrine pretreated with α1-blocker (prazosin); (4) epinephrine pretreated with α2-blocker (yohimbine); (5) epinephrine pretreated with β-blocker (propranolol); and (6) epinephrine pretreated with β- plus α1-blocker (propranolol and prazosin). Cardiopulmonary resuscitation was initiated after 8 minutes of untreated ventricular fibrillation and continued for an additional 8 minutes. The myocardial function and the serum concentrations of troponin I (Tn I) and N-terminal probrain natriuretic peptide (NT-proBNP) were measured at baseline and after resuscitation. After resuscitation, both Tn I and NT-proBNP were significantly increased in all groups, especially in the epinephrine and epinephrine pretreated with α2-blocker groups. Significantly better PR myocardial function and neurologic deficit score were observed in epinephrine pretreated with the α1- or β-blocker with decreased releases of Tn I and NT-proBNP. However, the most significant improvements were observed in the animals pretreated with β- plus α1-blocker. The present study demonstrated that myocardial stunning may not be the only mechanism of PR myocardial dysfunction. Administration of epinephrine increased the severity of PR myocardial tissue injury and dysfunction. The β- and β- plus α1-blocker pretreatment significantly reduced the severity of PR myocardial tissue injury and myocardial dysfunction with better neurologic function and prolonged duration of survival.

Effect of urinary protease inhibitor (ulinastatin) on cardiopulmonary bypass: a meta-analysis for China and Japan

OBJECTIVES

A meta-analysis was conducted to investigate the effects of ulinastatin treatment on adult patients undergoing cardiac surgery under cardiopulmonary bypass (CPB).

METHODS

Seven electronic databases were searched for reports of randomized, controlled trials conducted up to February 2014 in which patients undergoing cardiac surgery with CPB were administered ulinastatin in the perioperative period.

RESULTS

Fifty-two studies with 2025 patients were retained for analysis. The results showed that the ulinastatin can attenuate the plasma levels of pro-inflammatory cytokines and enhance the anti-inflammatory cytokine levels in patients undergoing cardiac surgery with CPB. Meanwhile, the ulinastatin had a significant beneficial effect on myocardial injury. The mean differences (MD) and 95% confidence intervals (95% CI) of biochemical markers were -63.54 (-79.36, -47.72) for lactate dehydrogenase, -224.99 (-304.83, -145.14) for creatine kinase, -8.75 (-14.23, -3.28) for creatine kinase-MB, and -0.14 (-0.20, -0.09] for troponin I (all P<0.01). However, neither hemodynamics nor cardiac function improved significantly, except that the MD and 95% CI of mean arterial pressure were 2.50 (0.19, 4.80) (P = 0.03). There were no statistically significant differences in the use of inotropes, postoperative bleeding, postoperative complications, the intensive care unit (ICU) stay, and the hospital stay; however, the frequency of auto resuscitation increased significantly (OR 1.98, 95%CI 1.19 to 3.30, P<0.01), the duration of intubation (MD -1.58, 95%CI -2.84 to -0.32, P<0.01) and the duration of mechanical ventilation (MD -3.29, 95%CI -4.41 to -2.17, P<0.01) shortened significantly in patients who were treated with ulinastatin.

CONCLUSIONS

Ulinastatin can reduce the plasma levels of pro-inflammatory cytokines and elevate anti-inflammatory cytokine in patients from China and Japan undergoing cardiac surgery with CPB. Ulinastatin treatment may have protective effects on myocardial injury, and can increase the frequency of auto resuscitation, shorten the duration of intubation and mechanical ventilation.