cytochrome-c-t and Heart-Arrest

Reversal of cardiac arrest requires reestablishment of aerobic metabolism by reperfusion with oxygenated blood of tissues that have been ischemic for variable periods of time. However, reperfusion concomitantly activates a myriad of pathogenic mechanisms causing what is known as reperfusion injury. At the center of reperfusion injury are mitochondria, playing a critical role as effectors and targets of injury. Studies in animal models of ventricular fibrillation have shown that limiting myocardial cytosolic Na+ overload attenuates mitochondrial Ca2+ overload and maintains oxidative phosphorylation, which is the main bioenergetic function of mitochondria. This effect is associated with functional myocardial benefits such as preservation of myocardial compliance during chest compression and attenuation of myocardial dysfunction after return of spontaneous circulation. Additional studies in similar animal models of ventricular fibrillation have shown that mitochondrial injury leads to activation of the mitochondrial apoptotic pathway, characterized by the release of cytochrome c to the cytosol, reduction of caspase-9 levels, and activation of caspase-3 coincident with marked reduction in left ventricular function. Cytochrome c also "leaks" into the bloodstream attaining levels that are inversely proportional to survival. These data indicate that mitochondria play a key role during cardiac resuscitation by modulating energy metabolism and signaling apoptotic cascades and that targeting mitochondria could represent a promising strategy for cardiac resuscitation.

Topics: Animals; Apoptosis; Calcium; Cardiopulmonary Resuscitation; Cytochromes c; Heart Arrest; Mitochondria; Mitochondrial Membrane Transport Proteins; Mitochondrial Membranes; Mitochondrial Permeability Transition Pore; Myocardial Reperfusion Injury; Oxidative Phosphorylation; Resuscitation; Sodium

Myocardial injury after cardiac arrest (CA) often results in severe myocardial dysfunction and death involving mitochondrial dysfunction. Here, we sought to investigate whether baicalin, a natural flavonoid compound, exerts cardioprotection against CA-induced injury via regulating mitochondrial dysfunction. We subjected the rats to asphyxia CA after a daily baicalin treatment for 4 weeks. After the return of spontaneous circulation, baicalin treatment significantly improved cardiac function performance, elevated survival rate from 35% to 75%, prevented necrosis and apoptosis in the myocardium, which was accompanied by reduced phosphorylation of Drp1 at serine 616, inhibited Drp1 translocation to the mitochondria and mitochondrial fission, and improved mitochondrial function. In H9c2 cells subjected to simulated ischemia/reperfusion, increased phosphorylation of Drp1 at serine 616 and subsequently enhanced mitochondrial Drp1 translocation as well as mitochondrial fission, augmented cardiomyocyte death, increased reactive oxygen species production, released cytochrome c from mitochondria and injured mitochondrial respiration were efficiently improved by baicalin and Drp1 specific inhibitor with Mdivi-1. Furthermore, overexpression of Drp1 augmented excessive mitochondrial fission and abolished baicalin-afforded cardioprotection, indicating that the protective impacts of baicalin are linked to the inhibition of Drp1. Altogether, our findings disclose for the first time that baicalin offers cardioprotection against ischemic myocardial injury after CA by inhibiting Drp1-mediated mitochondrial fission. Baicalin might be a prospective therapy for the treatment of post-CA myocardial injury.

Topics: Animals; Cell Line; Cell Respiration; Cytochromes c; Dynamins; Flavonoids; Heart Arrest; Hemodynamics; Male; Mitochondria; Mitochondrial Dynamics; Myocardium; Rats, Sprague-Dawley; Reactive Oxygen Species; Return of Spontaneous Circulation; Treatment Outcome

Cardiac arrest (CA) yields poor neurological outcomes. Salubrinal (Sal), an endoplasmic reticulum (ER) stress inhibitor, has been shown to have neuroprotective effects in both in vivo and in vitro brain injury models. This study investigated the neuroprotective mechanisms of Sal in postresuscitation brain damage in a rodent model of CA. In the present study, rats were subjected to 6 min of CA and then successfully resuscitated. Either Sal (1 mg/kg) or vehicle (DMSO) was injected blindly 30 min before the induction of CA. Neurological status was assessed 24 h after CA, and the cortex was collected for analysis. As a result, we observed that, compared with the vehicle-treated animals, the rats pretreated with Sal exhibited markedly improved neurological performance and cortical mitochondrial morphology 24 h after CA. Moreover, Sal pretreatment was associated with the following: (1) upregulation of superoxide dismutase activity and a reduction in maleic dialdehyde content; (2) preserved mitochondrial membrane potential; (3) amelioration of the abnormal distribution of cytochrome C; and (4) an increased Bcl-2/Bax ratio, decreased cleaved caspase 3 upregulation, and enhanced HIF-1

Topics: Aldehydes; Animals; Apoptosis; Brain Injuries; Cardiopulmonary Resuscitation; Caspase 3; Cerebellar Cortex; Cinnamates; Cytochromes c; Endoplasmic Reticulum Stress; Heart Arrest; Hypoxia-Inducible Factor 1, alpha Subunit; Male; Membrane Potential, Mitochondrial; Microscopy, Electron, Transmission; Mitochondria; Neuroprotective Agents; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Sprague-Dawley; Superoxide Dismutase-1; Thiourea

At abnormally elevated levels of intracellular Ca

Topics: Animals; Brain; Brain Ischemia; Calcium; Cytochromes c; Dogs; Female; Heart Arrest; Mitochondria

Mitochondrial injury post-cardiac arrest has been described in pre-clinical settings but the extent to which this injury occurs in humans remains largely unknown. We hypothesized that increased levels of mitochondrial biomarkers would be associated with mortality and neurological morbidity in post-cardiac arrest subjects.. We performed a prospective multicenter study of post-cardiac arrest subjects. Inclusion criteria were comatose adults who suffered an out-of-hospital cardiac arrest. Mitochondrial biomarkers were measured at 0, 12, 24, 36 and 48h after return of spontaneous circulation as well as in healthy controls.. Out of 111 subjects enrolled, 102 had evaluable samples at 0h. Cardiac arrest subjects had higher baseline cytochrome c levels compared to controls (2.18ng/mL [0.74, 7.74] vs. 0.16ng/mL [0.03, 0.91], p<0.001), and subjects who died had higher 0h cytochrome c levels compared to survivors (3.66ng/mL [1.40, 14.9] vs. 1.27ng/mL [0.16, 2.37], p<0.001). There were significantly higher Ribonuclease P (RNaseP) (3.3 [1.2, 5.7] vs. 1.2 [0.8, 1.2], p<0.001) and Beta-2microglobulin (B2M) (12.0 [1.0, 22.9], vs. 0.6 [0.6, 1.3], p<0.001) levels in cardiac arrest subjects at baseline compared to the control subjects. There were no differences between survivors and non-survivors for mitochondrial DNA, nuclear DNA, or cell free DNA.. Cytochrome c was increased in post- cardiac arrest subjects compared to controls, and in post-cardiac arrest non-survivors compared to survivors. Nuclear DNA and cell free DNA was increased in plasma of post-cardiac arrest subjects. There were no differences in mitochondrial DNA, nuclear DNA, or cell free DNA between survivors and non-survivors. Mitochondrial injury markers showed mixed results in the post-cardiac arrest period. Future research needs to investigate these differences.

Topics: Aged; Cardiopulmonary Resuscitation; Coma; Cytochromes c; DNA, Mitochondrial; Female; Heart Arrest; Humans; Male; Middle Aged; Mitochondria; Nervous System Diseases; Ribonuclease P; Statistics as Topic; Survival Analysis; Survivors

Therapeutic hypothermia is effective to attenuate brain ischemia/reperfusion (I/R) injury after cardiac arrest, and multiple mechanisms have been proposed. Dynamin-related protein 1 (Drp1), a large GTPases of dynamin superfamily, predominantly controls mitochondrial fission and is related to IR-induced Cyt C release and apoptosis. However, the effect of therapeutic hypothermia on Drp1 and mitochondrial fission after cardiac arrest remains still unclear. In this study, non-cardiac arrest and post-cardiac arrest rats received 6-h normothermia (37-38°C) or therapeutic hypothermia (32-34°C), and the hippocampus was harvested at 6h and 72h after cardiac arrest. Results showed the expression of Drp1 and Cyt C increased after cardiac arrest, but therapeutic hypothermia partially reversed this increase at 6h after cardiac arrest. Transmission electron microscopy (TEM) also showed a change in morphology following therapeutic hypothermia after cardiac arrest. Moreover, therapeutic hypothermia could decrease the histopathological damage, inhibit the apoptosis of CA1 neurons and improve the survival and neurological outcomes at 72h after cardiac arrest. Taken together, our study demonstrates that therapeutic hypothermia is neuroprotective against global cerebral I/R injury, which is, at least partially, ascribed to the inhibition Drp1 and Cyt C expression and the protection of mitochondrial structure.

Topics: Animals; Apoptosis; Brain Ischemia; Cytochromes c; Dynamins; Heart Arrest; Hippocampus; Hypothermia, Induced; Male; Mitochondria; Neurons; Rats, Sprague-Dawley; Reperfusion Injury

To investigate the effects of mitochondrial division inhibitor 1 (mdivi-1) in rats after cardiopulmonary resuscitation (CPR) and its mechanism.. Fifty Sprague-Dawley (SD) rats were randomly (random number table) divided into sham group (n = 8), cardiac arrest (CA) model group (n = 14), dimethyl sulfoxide post-treatment control group (DMSO group, n = 14), and mdivi-1 post-treatment group (mdivi-1 group, n = 14). Asphyxial CA was reproduced in animals, and they were resuscitated by CPR. In the mdivi-1 group or DMSO group, the animals were given mdivi-1 (1.2 mg/kg) or DMSO (0.1%) intravenously after restoration of spontaneous circulation ( ROSC ). The neurological functions were assessed using neurological deficit score (NDS) determined at 24, 48 and 72 hours after CPR. The brain tissues were harvested at 72 hours after CPR. The histopathologic changes were assessed by hematoxylin and eosin (HE) staining, and the normal neuron was counted. The neuronal apoptosis was assessed with terminal dexynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining, and the expressions of cytochrome C (Cyt-C) protein in mitochondria and cytoplasm from hippocampus were determined by Western Blot.. NDS in all experiment groups was gradually increased after CPR, and they were significantly lower than those of the sham group at 24, 48, and 72 hours (51.5 ± 3.7 vs. 80.0 ± 0.0, 59.3 ± 3.6 vs. 80.0 ± 0.0, 66.7 ± 2.6 vs. 80.0 ± 0.0, all P < 0.05). The number of normal pyramidal neurons in the hippocampal CA1 region was markedly reduced (cells/HP: 4.4 ± 1.1 vs. 23.1 ± 4.0, P < 0.05), the apoptotic index was significantly increased [(86.9 ± 6.9)% vs. (3.4 ± 0.8)%, P < 0.05], the expressions of Cyt-C in mitochondria were significantly decreased (A value: 0.46 ± 0.18 vs. 1.00 ± 0.00, P < 0.05), and the expressions of Cyt-C in cytoplasm were significantly up-regulated (A value: 6.65 ± 0.21 vs. 1.00 ± 0.00, P < 0.05). Compared with the CA group, NDS at 24 hours and 48 hours in mdivi-1 group was slightly increased (55.2 ± 3.3 vs. 51.5 ± 3.7, 64.7 ± 2.4 vs. 59.3 ± 3.6, both P > 0.05), and it was significantly increased at 72 hours (74.5 ± 2.3 vs. 66.7 ± 2.6, P < 0.05), the number of normal pyramidal neurons in the hippocampal CA region was markedly increased (cells/HP: 16.2 ± 2.4 vs. 4.4 ± 1.1, P < 0.05), the apoptotic index was dramatically reduced [(42.3 ± 3.9 )% vs. (86.9 ± 6.9 )%, P < 0.05], the expressions of Cyt-C in mitochondria were significantly increased (A value: 0.83 ± 0.22 vs. 0.46 ± 0.18, P < 0.05), and the expressions of Cyt-C in cytoplasm were significantly decreased (A value: 3.84 ± 0.47 vs. 6.65 ± 0.21, P < 0.05). There was no statistically significant difference in above indexes between CA group and DMSO group.. By inhibiting mitochondrial Cyt-C apoptotic pathway to reduce neuronal apoptosis in rats after CA-CPR, mdivi-1 can improve brain function after CPR.

Topics: Animals; Apoptosis; Asphyxia; Cardiopulmonary Resuscitation; Cytochromes c; Heart Arrest; Mitochondria; Neurons; Quinazolinones; Random Allocation; Rats; Rats, Sprague-Dawley

To investigate the protective effect of anisodamine on myocardial mitochondrial damage in cardiac arrest (CA) in pigs.. Twenty-three male pigs were randomly divided into three groups, epinephrine group (n=9), anisodamine group (n=9) and control group (n=5). CA following ventricular fibrillation (VF) was induced by alternating current. The blood samples were collected before CA, 8 minutes after CA and instantly after recovery of spontaneous circulation (ROSC), and 30 minutes and 24 hours later. Hearts were obtained at 24 hours after ROSC. The changes in Cytochrome C (Cyt C) and caspase-3 in plasma and myocardium were analyzed by enzyme-linked immunosorbent assay (ELISA). The myocardial specimens were observed by transmission electron microscopy for ultrastructural changes, and apoptosis was assessed with Hoechst 33258 staining.. The ROSC rate of the anisodamine group was elevated by 22.22% compared with the epinephrine group (77.78% vs. 55.56%, P>0.05). All animals with resumption of ROSC survived up to 24 hours. The plasma contents of Cyt C and caspase-3 in the epinephrine group and the anisodamine group gradually increased after ROSC, and were significantly higher than those in the control group. But the plasma Cyt C level in the anisodamine group was lower than that in the epinephrine group at 30 minutes and 24 hours after ROSC (48.68±19.50 nmol/L vs. 77.51±29.87 nmol/L, 48.98±20.26 nmol/L vs. 82.11±25.09 nmol/L, both P<0.05). There was no significant difference in protein contents of both Cyt C and caspase-3 in plasma and myocardium between two resuscitate groups. Both epinephrine and anisodamine could mitigate cardiac mitochondrial damage after CA, but the anisodamine showed better effect. The myocardium apoptosis ratio in the anisodamine group was lower than that of the epinephrine group [(0.15±0.04)% vs. (0.37±0.04)%, P<0.01].. By decreasing the protein content of Cyt C, and reducing the extent of damage to myocardial mitochondria, anisodamine can protect the myocardial ultrastructure, and restrain the mitochondria-induced cell apoptosis after resuscitation.

Topics: Animals; Apoptosis; Cardiopulmonary Resuscitation; Caspase 3; Cytochromes c; Epinephrine; Heart Arrest; Male; Mitochondria, Heart; Myocardium; Random Allocation; Resuscitation; Solanaceous Alkaloids; Swine; Ventricular Fibrillation

Cerebrospinal fluid (CSF) proteins may be useful biomarkers of neuronal death and ultimate prognosis after hypoxic-ischemic brain injury. Cytochrome c has been identified in the CSF of children following traumatic brain injury. Cytochrome c is required for cellular respiration but it is also a central component of the intrinsic pathway of apoptosis. Thus, in addition to serving as a biomarker, cytochrome c release into CSF may have an effect upon survival of adjacent neurons. In this study, we use Western blot and ELISA to show that cytochrome c is elevated in CSF obtained from pediatric rats following resuscitation from cardiac arrest. Using biotinylated human cytochrome c in culture media we show that cytochrome c crosses the cell membrane and is incorporated into mitochondria of neurons exposed to anoxia. Lastly, we show that addition of human cytochrome c to primary neuronal culture exposed to anoxia improves survival. To our knowledge, this is the first study to show cytochrome c is elevated in CSF following hypoxic ischemic brain injury. Results from primary neuronal culture suggest that extracellular cytochrome c is able to cross the cell membrane of injured neurons, incorporate into mitochondria, and promote survival following anoxia.

Topics: Animals; Cell Hypoxia; Cell Survival; Cytochromes c; Heart Arrest; Male; Neurons; Rats; Rats, Sprague-Dawley

Mitochondrial biology appears central to many conditions that progress to death but remains poorly characterized after cardiac arrest. Mitochondrial dysfunction in electron transfer and reactive oxygen species leakage during ischemia may lead to downstream events including mitochondrial protein oxidation, tyrosine nitrosylation, cytochrome c loss, and eventual death. We sought to better define early fixed alterations in these mitochondrial functions after whole animal cardiac arrest.. We used a murine model of 8 mins of untreated KCl-induced cardiac arrest followed by resuscitation and return of spontaneous circulation to study mitochondrial functions in four groups of animals: 1) after 8 min cardiac arrest (CA8) but no resuscitation, 2) 30 min postreturn of spontaneous circulation (R30), 3) 60 min postreturn of spontaneous circulation (R60), and in 4) shams. Heart mitochondria were immediately harvested, isolated, and stored at -80 degrees C for later spectrophotometric measurements of electron transfer activities and reactive oxygen species leakage using appropriate substrates and inhibitors. Mitochondrial cytochrome c content and tyrosine nitration were analyzed by Western blot and densitometry.. A significant reactive oxygen species leakage from complex I was evident after just 8 min of cardiac arrest (CA8 group, p < .05), which was followed by a progressive reduction in complex I electron transfer activity (CA8 > R30 > R60). In contrast, complex II and II-III activities appeared more resistant to ischemia at the time points evaluated. Early changes in a approximately 50 kDa and approximately 25 kDa protein were observed in tyrosine nitration along with a loss of cytochrome c.. A relatively "orderly" process of mitochondrial dysfunction progresses during ischemia and reperfusion. Changes in mitochondrial reactive oxygen species generation and electron transfer from complex I occur along with tyrosine nitrosylation and loss of cytochrome c; these may represent important new targets for future human therapies.

Topics: Animals; Cardiopulmonary Resuscitation; Coronary Circulation; Cytochromes c; Electrocardiography; Electron Transport; Female; Heart Arrest; Hydrogen Peroxide; Mice; Mice, Inbred C57BL; Mitochondria; Myocardial Ischemia; Myocardial Reperfusion; Myocardium; Reactive Oxygen Species; Respiration, Artificial; Succinate Cytochrome c Oxidoreductase; Tyrosine

Ca(2+) overload and reactive oxygen species can injure mitochondria during ischemia and reperfusion. We hypothesized that mitochondrial injury occurs during cardiac resuscitation, causing release of cytochrome c to the cytosol and bloodstream while activating apoptotic pathways. Plasma cytochrome c was measured using reverse-phase HPLC and Western immunoblotting in rats subjected to 4 or 8 min of untreated ventricular fibrillation and 8 min of closed-chest resuscitation followed by 240 min of postresuscitation hemodynamic observation. A sham group served as control. Plasma cytochrome c rose progressively to levels 10-fold higher than in sham rats 240 min after resuscitation (P < 0.01), despite reversal of whole body ischemia (decreases in arterial lactate). Cytochrome c levels were inversely correlated with left ventricular stroke work (r = -0.40, P = 0.02). Western immunoblotting of left ventricular tissue demonstrated increased levels of 17-kDa cleaved caspase-3 fragments in the cytosol. Plasma cytochrome c was then serially measured in 12 resuscitated rats until the rat died or cytochrome c returned to baseline. In three survivors, cytochrome c rose slightly to

Topics: Animals; Apoptosis; Biomarkers; Blotting, Western; Caspase 3; Chromatography, High Pressure Liquid; Cytochromes c; Disease Models, Animal; Electric Stimulation; Heart Arrest; Heart Ventricles; Leukocytes; Male; Mitochondria, Heart; Predictive Value of Tests; Prognosis; Rats; Rats, Sprague-Dawley; Resuscitation; Severity of Illness Index; Time Factors; Ventricular Fibrillation; Ventricular Function, Left

Non-heart-beating donors are expected to ameliorate shortages of donors for organ transplantation. The issue of preventing warm ischemic injury after circulatory arrest must be investigated. In the current study, we investigated whether isoflurane inhalation during warm ischemia could attenuate ischemia reperfusion injury (IRI) of the lung.. An isolated perfused rat lung model was used. The rats were allocated into four groups: the no ischemia group; the ischemia-1 minimum alveolar concentration (MAC) iso group (ventilation with air and 1.38% isoflurane); the Ischemia-3MAC iso group (ventilation with air and 4.2% isoflurane); and the Ischemia-no treatment group (ventilation with only air). Lungs were subjected to 50 min of ischemia at 37 degrees C. Physiological lung functions were measured after reperfusion in experiment one. Mitochondrial control ratio (RCR), cytochrome-c release from mitochondria, and caspase activities just after warm ischemia were measured in experiment two.. Pulmonary functions in the Ischemia-1MAC iso group were significantly greater than those in the Ischemia-no treatment group for experiment one. There were no dose-dependent effects between 1MAC and 3MAC isoflurane. In experiment two, RCR in the Ischemia-1MAC iso group was significantly greater than that in the Ischemia-no treatment group. Cytochrome-c release and caspase-9 activity in the Ischemia-1MAC iso group were significantly decreased compared to those in the Ischemia-no treatment group.. Isoflurane inhalation attenuates warm IRI with the protection of mitochondria. Our results suggest that isoflurane inhalation after circulatory arrest can be a simple and effective method to protect the lung against warm ischemia.

Topics: Administration, Inhalation; Anesthetics, Inhalation; Animals; Blood Circulation; Caspase 9; Cell Respiration; Cytochromes c; Heart Arrest; In Vitro Techniques; Isoflurane; Lung; Mitochondria; Rats; Reperfusion Injury; Vascular Resistance; Warm Ischemia; Weight Gain

Protein kinase C (PKC) isozymes have been known to mediate a variety of complex and diverse cellular functions. deltaPKC has been implicated in mediating apoptosis. Using two models of cerebral ischemia, cardiac arrest in rats and oxygen glucose deprivation (OGD) in organotypic hippocampal slices, we tested whether an ischemic insult promoted deltaPKC cleavage during the reperfusion and whether the upstream pathway involved release of cytochrome c and caspase 3 cleavage. We showed that cardiac arrest/OGD significantly enhanced deltaPKC translocation and increased its cleavage at 3 h of reperfusion. Since deltaPKC is one of the substrates for caspase 3, we next determined caspase 3 activation after cardiac arrest and OGD. The maximum decrease in levels of procaspase 3 was observed at 3 h of reperfusion after cardiac arrest and OGD. We also determined cytochrome c release, since it is upstream of caspase 3 activation. Cytochrome c in cytosol increased at 1 h of reperfusion after cardiac arrest/OGD. Inhibition of either deltaPKC/caspase 3 during OGD and early reperfusion resulted in neuroprotection in CA1 region of hippocampus. Our results support the deleterious role of deltaPKC in reperfusion injury. We propose that early cytochrome c release and caspase 3 activation promote deltaPKC translocation/cleavage.

Topics: Animals; Blood Pressure; Brain Ischemia; Caspase 3; Caspases; Cell Death; Cytochromes c; Electrocardiography; Glucose; Heart Arrest; Hippocampus; Nerve Degeneration; Organ Culture Techniques; Oxygen; Protein Kinase C; Protein Kinase C-delta; Rats; Rats, Sprague-Dawley; Signal Transduction