Mechanisms and treatment of anemia related to cardiac arrest. / å¿ƒè„éª¤åœåŽç›¸å ³æ€§è´«è¡€çš„æœºåˆ¶åŠæ²»ç–—.

Cardiac arrest is a common and fatal emergency situation. Recently, an increasing number of studies have shown that anemia in patients with cardiac arrest is closely related to high mortality rates and poor neurological outcomes. Anemia is prevalent among patients with post-cardiac arrest syndrome (PCAS), but its specific pathogenesis remains unclear. The mechanisms may involve various factors, including reduced production of erythropoietin, oxidative stress/inflammatory responses, gastrointestinal ischemic injury, hepcidin abnormalities, iatrogenic blood loss, and malnutrition. Measures to improve anemia related to cardiac arrest may include blood transfusions, administration of erythropoietin, anti-inflammation and antioxidant therapies, supplementation of hematopoietic materials, protection of gastrointestinal mucosa, and use of hepcidin antibodies and antagonists. Therefore, exploring the latest research progress on the mechanisms and treatment of anemia related to cardiac arrest is of significant guiding importance for improving secondary brain injury caused by anemia and the prognosis of patients with cardiac arrest.

Effects of peripheral blood cells on ischemic stroke: Greater immune response or systemic inflammation?

Ischemic stroke is still one of the most serious medical conditions endangering human health worldwide. Current research on the mechanism of ischemic stroke focuses on the primary etiology as well as the subsequent inflammatory response and immune modulation. Recent research has revealed that peripheral blood cells and their components are crucial to the ensuing progression of ischemic stroke. However, it remains unclear whether blood cell elements are principally in charge of systemic inflammation or immunological regulation, or if their participation is beneficial or harmful to the development of ischemic stroke. In this review, we aim to describe the changes in peripheral blood cells and their corresponding parameters in ischemic stroke. Specifically, we elaborate on the role of each peripheral component in the inflammatory response or immunological modulation as well as their interactions. It has been suggested that more specific therapies aimed at targeting peripheral blood cell components and their role in inflammation or immunity are more favorable to the treatment of ischemic stroke.

Minimally invasive puncture combined with a high frequency of urokinase therapy improves outcomes in patients with HICH.

Minimally invasive puncture combined with urokinase is widely used in the treatment of hypertensive intracerebral hemorrhage (HICH). However, the appropriate frequency of urokinase following minimally invasive puncture in patients is still unclear. In total, 55 patients were enrolled in this study. According to the frequency of urokinase (10.0 â€‹× â€‹104 units) administration, 30 patients received urokinase at Q4h, while the other 25 patients received urokinase at Q8h. In the univariate analysis, preoperative GCS (p â€‹= â€‹0.0002), postoperative GCS (p â€‹= â€‹0.0007), the volume of residual hematoma (p â€‹= â€‹0.0179), and the frequency of urokinase (p â€‹= â€‹0.0110) were associated with unfavorable outcomes in patients with HICH in the basal ganglia. The multivariate analysis revealed that the frequency of urokinase was independently associated with unfavorable outcomes in patients with HICH in the basal ganglia (p â€‹= â€‹0.038, 1.109-35.380). The drainage time was significantly shorter in the Q4h group (14.17 â€‹± â€‹0.86 â€‹h) than in the Q8h group (27.36 â€‹± â€‹1.39 â€‹h) (p â€‹< â€‹0.0001). The GOS (4.37 â€‹± â€‹0.18), BI (75.52 â€‹± â€‹2.39), and mRS (1.67 â€‹± â€‹0.24) in the Q4h group were significantly ameliorated compared to those in the Q8h group (GOS 3.56 â€‹± â€‹0.18, BI 64.13 â€‹± â€‹2.22, and mRS 2.64 â€‹± â€‹0.28, respectively) (p â€‹= â€‹0.0004, p â€‹= â€‹0.0002, and p â€‹= â€‹0.0018) at 3 months of follow-up. Thus, minimally invasive puncture combined with urokinase is safe and efficient. Increasing the frequency of urokinase administration can produce faster and better postoperative recovery for patients with HICH in the basal ganglia.

Cdk1 protects against oxygen-glucose deprivation and reperfusion-induced Golgi fragmentation and apoptosis through mediating GM130 phosphorylation.

Increasing evidence has indicated that the Golgi apparatus (GA) is involved in the development of cerebral ischemia-reperfusion (IR) injury. Finding effective neuroprotective agents targeting GA has become a priority in the treatment of ischemic stroke. GM130, a key structural protein present on the cis-face of the GA, maintains its structure through its phosphorylation and dephosphorylation. However, the molecular mechanisms by which GM130 regulates IR-induced neuronal apoptosis are not well elucidated. Mouse neuroblastoma Neuro2a (N2A) cells were subjected to oxygen-glucose deprivation and reperfusion (OGDR) insult. Cell proliferation and apoptosis were determined using MTT assay, TUNEL staining, and flow cytometry. GA morphology was detected by immunocytochemical staining and immunofluorescence microscopy. GA-related protein and mRNA levels were detected by WB and qPCR, respectively. Treatment with Purvalanol A, an effective Cdk1 inhibitor, and transfection of Cdk1-shRNA were carried out to inhibit OGDR-induced Cdk1 elevation. The results demonstrated that OGDR induced Golgi fragmentation, neuronal apoptosis, GM130 phosphorylation, and p115 cleavage in N2A cells. Cdk1 elevation after OGDR was closely correlated with GM130 phosphorylation, not p115. Inhibition of Cdk1 significantly attenuated OGDR-induced Golgi fragmentation and cell apoptosis. Cdk1 interacted with GM130 and decreased its phosphorylation on the serine 25 site in N2A cells exposed to OGDR. The present findings reveal that Cdk1 protects against IR-induced GA fragmentation and apoptosis, likely through the mediation of GM130 phosphorylation. This neuroprotective potential of Cdk1 against IR insult and the underlying mechanism will pave the way for potential clinical applications targeting the GA organelle for cerebral IR-related disorders.

Sodium valproate-induced nocturnal enuresis in epilepsy: Three case reports and a review of the literature.

Background: Enuresis is an uncommon adverse effect of sodium valproate therapy that is unknown to most clinicians. This study provides an overview of the literature on enuresis associated with sodium valproate therapy, discussing the clinical manifestations and possible mechanisms of this side effect. Methods: We reported three cases of enuresis induced by sodium valproate and reviewed the published enuresis cases associated with sodium valproate therapy retrieved from databases. Case presentation and results: Three new patients with epilepsy who presented with enuresis following sodium valproate therapy were reported, and 55 published cases of nocturnal enuresis associated with sodium valproate were evaluated. The average age of these patients varied from 4 to 20 years. A total of 48 cases had generalized seizures, seven had focal seizures, and three had unknown seizures. In all the patients, the plasma concentration of sodium valproate was 80.76 ± 14.80 µg/mL, within the therapeutic range when enuresis occurred. With discontinuation or reduction of the drug, all the patients recovered completely. Conclusion: Sodium valproate-induced enuresis is a rare and reversible side effect, occurring at a younger age, characterized by the generalized onset of seizures, and a rather high dose. The possible mechanisms include insufficient secretion of anti-diuretic hormones, sleep disorder, and hyperactivity of the parasympathetic system. Clinicians should be aware of this uncommon side effect to avoid an incorrect adjustment of the treatment direction.

Clinical Features of Aortic Dissection in the Emergency Department: A Single-center Experience from South China.

OBJECTIVES: Our goal in this study was to determine 1) whether there are any differences in clinical characteristics between Chinese and Western patients with aortic dissection (AD), and 2) the mortality rate of AD patients in the emergency department (ED) and identify the risk predictors for death. METHODS: We retrospectively analyzed patients who were diagnosed with AD and admitted to our ED between September 1, 2017-August 31, 2020. Data on age, gender, clinical manifestation, medical history, routine blood tests, liver and kidney function, coagulation, myocardial enzymology, and mortality were collected. RESULTS: We enrolled 535 AD patients (422 men and 113 women) with a mean age of 54.7±14.1 years. Type A AD constituted 40% of the total number of AD cases, while type B AD constituted 60%. The proportion of those who were females, 10-92 years, with type A AD, and hypertension in the Chinese population was lower than that in the Western population (P <0.05 for all). Type A AD patients had a higher proportion of acute AD clinical manifestations than did patients with type B AD (P = 0.0084, P <0.05). The mortality rate of type A AD patients (10.75%) was higher than that of type B AD patients (1.87%) (P <0.0001) in the ED. Higher values of white blood cells, neutrophils, high-density lipoprotein, activated partial thromboplastin time, and D-dimer level with worsened hepatic and renal function were found in the deceased group, and multivariate logistic regression revealed that blood urea nitrogen (BUN) levels (P = 0.0031, P <0.05) were significantly associated with death. CONCLUSION: In South China, patients with AD had a mean age of 54.7 years, with 78.88% prevalence in males and 66.92% hypertension rate. Type A AD accounted for 40% of all AD cases, and 10.70% of patients with type A AD died in the ED. Elevated BUN levels may be a risk predictor for death in patients with type A AD.

Extracorporeal membrane oxygenation rescue for severe pneumocystis pneumonia with the Macklin effect: a case report.

BACKGROUND: Pneumocystis jirovecii pneumonia (PJP) in an immunocompromised host is often associated with the Macklin effect, which can progress to spontaneous pneumomediastinum (SPM), subcutaneous emphysema (SCE), and pneumothorax (PNX). Diagnosing the causative organism of these conditions in non-HIV infected patients and treating hypoxemia while preventing further lung damage can be challenging. This study examines the case of a non-HIV infected male with SPM, SCE, and PNX secondary to severe Pneumocystis jirovecii (PJ) infection. CASE PRESENTATION: A 53-year-old male with pure red cell aplasia (PRCA) was admitted with fever, dry cough, and shortness of breath. His respiratory function progressively deteriorated due to the development of SPM, SCE, and PNX, eventually requiring endotracheal intubation and invasive ventilation. As a result of high pressure in his airways occasioned by lung recruitment maneuvers, his pulmonary parameters worsened, necessitating veno-venous (VV) extracorporeal membrane oxygenation (ECMO) therapy. The early initiation of VV-ECMO facilitated ultra-protective lung ventilation and prevented the progression of SPM, SCE, and PNX. Traditional diagnostic assays were unrevealing, whereupon the patient resorted to the metagenomic next-generation sequencing technology for uncovering potential pathogens. Consequently, we detected a significantly higher infection by PJ in the patient's bronchoscopy lavage fluid. Finally, the patient was successfully treated with appropriate antimicrobials and was decannulated after nine days of ECMO support. CONCLUSIONS: SPM, SCE, and PNX are rare clinical manifestations of PJP. However, they can be considered as poor prognostic factors of the infection. Physicians should, therefore, be alert to the possibility of PJP in immunocompromised patients.

FDG-PET/CT Assessment of the Cerebral Protective Effects of Hydrogen in Rabbits with Cardiac Arrest.

BACKGROUND: Anatomical imaging methods and histological examinations have limited clinical value for early monitoring of brain function damage after cardiac arrest (CA) in vivo. OBJECTIVE: We aimed to assess the cerebral protective effects of hydrogen in rabbits with CA by using fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT). METHODS: Male rabbits were divided into the hydrogen-treated (n=6), control (n=6), and sham (n=3) groups. Maximum standardized uptake values (SUVmax) were measured by FDG-PET/CT at baseline and post-resuscitation. Blood Ubiquitin C-terminal hydrolase-L1 (UCH-L1) and neuron-specific enolase (NSE) were measured before and after the operation. After surgical euthanasia, brain tissues were extracted for Nissl staining. RESULTS: SUVmax values first decreased at 2 and 24 h after resuscitation before rising in the hydrogentreated and control groups. SUVmax values in the frontal, occipital, and left temporal lobes and in the whole brain were significantly different between the hydrogen and control groups at 2 and 24 h postresuscitation (P<0.05). The neurological deficit scores at 24 and 48 h were lower in the hydrogentreated group (P<0.05). At 24 h, the serum UCH-L1 and NSE levels were increased in the hydrogen and control groups (P<0.05), but not in the sham group. At 48 and 72 h post-CA, the plasma UCH-L1 and NSE levels in the hydrogen and control groups gradually decreased. Neuronal damage was smaller in the hydrogen group compared to the control group at 72 h. CONCLUSION: FDG-PET/CT could be used to monitor early cerebral damage, indicating a novel method for evaluating the protective effects of hydrogen on the brain after CA.

Successful treatment of severe electrolyte imbalance-induced cardiac arrest caused by adrenal tuberculosis with ECMO in the ED.

BACKGROUND: Tuberculosis (TB) is a chronic infectious disease, common in China. TB bacteria can invade multiple organs throughout the body, but they rarely cause critical illness. We present a complex critically ill case in this report. CASE PRESENTATION: A 40-year-old man suffered sudden cardiac arrest during an emergency room visit. Spontaneous circulation resumed after emergency cardiopulmonary resuscitation (CPR), but recurrent ventricular fibrillation and refractory cardiac shock emerged. Thereafter, extracorporeal membrane oxygenation (ECMO) was implemented to maintain hemodynamic stability. Blood test results revealed that the patient had severe electrolyte imbalance and adrenal insufficiency. Further imaging examination showed multiple tuberculosis lesions throughout the body, including the lungs, adrenal glands, and lumbar spine. In the end, the patient was successfully moved from the ICU after weaning from ECMO and the ventilator, and then transferred to an infectious disease specialist hospital for standard anti-tuberculosis therapy. CONCLUSIONS: ECMO has won the opportunity for the diagnosis and treatment of this young patient who suffered from a rare cause of cardiac arrest and finally achieved a good prognosis.

Therapeutical plasma exchange for thrombotic thrombocytopenic purpura in the emergency department: A single center experience.

INTRODUCTION: Thrombotic thrombocytopenic purpura (TTP) is a rare, life-threatening and easily misdiagnosed thrombotic microangiopathy disease. Few studies have reported the use of therapeutic plasma exchange (TPE) for TTP in emergency departments in China. The present study was a retrospective analysis of patients with TTP who were treated with TPE in our emergency intensive care unit (EICU). METHODS: This study retrospectively analyzed patients with TTP who received TPE management from July 1, 2014 to February 1, 2020. The following clinical data of these patients were collected: laboratory results, first symptoms, ADAMTS13 levels, glucocorticoid levels, TPE times and outcomes. RESULTS: The study included 19 patients (9 male and 10 female) with 20 clinical episodes, and 1 female patient had two episodes. TPE was used in 17 patients, and TPE was performed once every 2-3 days in patients. The volume for each TPE treatment was 2000 ml. In total, 4 male patients died, and 15 patients survived. One female experienced a relapse. No significant differences in age, RBC, HGB, PLT, ALT, AST, BUN, Cr, LDH, or bilirubin were noted between the survival and death groups. The mortality rate of male patients was significantly higher than that of female patients(p = 0.0325, p < 0.05), and the mean age of deceased patients was 64.25 ± 4.78 years, which was older than the mean age of survivors (47.38 ± 4.30). However, no significant difference was noted (p = 0.0787). CONCLUSION: TPE had satisfactory results for TTP patients although it was not performed every day. Older male TTP patients exhibited a relatively increased risk of death.

Green Tea Polyphenols Protect against Acetaminophen-Induced Liver Injury by Regulating the Drug Metabolizing Enzymes and Transporters.

Green tea polyphenols (GTPs) have been shown to exhibit diverse beneficial effects against a variety of diseases. Acetaminophen (APAP) overdose is one of the most frequent causes of drug-induced liver injury. In the current study, we aimed to investigate the protective effect of GTP on APAP-induced liver injury in mice and the underlying mechanisms involved. Male C57BL/6J mice were treated orally with different doses of GTP (37.5, 75, or 150 mg/kg) 4 h after APAP overdose (400 mg/kg) and continuously given every 8 h until sacrificed at 4, 12, 20, and 48 h after the first treatment of GTP. Survival rate and histological and biochemical assessments were performed to evaluate the APAP-induced liver injury. Protein expression of multiple drug metabolizing enzymes and transporters was measured to demonstrate the possible mechanisms involved. Our results revealed that administration of different doses of GTP significantly alleviated APAP-induced liver injury by improving the survival rate, hepatocellular necrosis, and ALT/AST/GSH levels after APAP overdose (400 mg/kg). The protein expression of APAP-induced drug transporters and metabolizing enzymes was mostly induced by GTP treatment, which was followed by reduction in drug transporters at the later time points. The current study collectively demonstrated that GTP protects against APAP-induced liver injury, possibly through regulating drug metabolizing enzymes and transporters after APAP overdose.

The circular RNA 001971/miR-29c-3p axis modulates colorectal cancer growth, metastasis, and angiogenesis through VEGFA.

BACKGROUND: Colorectal cancer (CRC) is one of the most common malignant tumors globally. Angiogenesis is a key event maintaining tumor cell survival and aggressiveness. The expression of vascular endothelial growth factor A (VEGFA), one of the most significant tumor cell-secreted proangiogenic factors, is frequently upregulated in CRC. METHODS: The MTT assay was used to detect the viability of CRC cells. Transwell assays were performed to detect the invasion capacity of target cells. Relative protein levels were determined by immunoblotting. Pathological characteristics of tissues were detected by H&E staining and immunohistochemical (IHC) staining. A RIP assay was conducted to validate the predicted binding between genes. RESULTS: We observed that circ-001971 expression was dramatically increased in CRC tissue samples and cells. Circ-001971 knockdown suppressed the capacity of CRC cells to proliferate and invade and HUVEC tube formation in vitro, as well as tumor growth in mice bearing SW620 cell-derived tumors in vivo. The expression of circ-001971 and VEGFA was dramatically increased whereas the expression of miR-29c-3p was reduced in tumor tissue samples. Circ-001971 relieved miR-29c-3p-induced inhibition of VEGFA by acting as a ceRNA, thereby aggravating the proliferation, invasion and angiogenesis of CRC. Consistent with the above findings, the expression of VEGFA was increased, whereas the expression of miR-29c-3p was decreased in tumor tissue samples. miR-29c-3p had a negative correlation with both circ-001971 and VEGFA, while circ-001971 was positively correlated with VEGFA. CONCLUSIONS: In conclusion, the circ-001971/miR-29c-3p axis modulated CRC cell proliferation, invasion, and angiogenesis by targeting VEGFA.

PAQR3 protects against oxygen-glucose deprivation/reperfusion-induced injury through the ERK signaling pathway in N2A cells.

Cerebral ischemia-reperfusion injury is pivotal in the development of multiple-subcellular organelle and tissue injury after acute ischemic stroke. Recently, the Golgi apparatus (GA) has been shown to be a key subcellular organelle that plays an important role in neuroprotection against oxygen-glucose deprivation/reperfusion (OGD/R) injury. PAQR3, a scaffold protein exclusively localized in the GA, was originally discovered as a potential tumor suppressor protein. PAQR3 acts as a spatial regulator of Raf-1 that binds Raf-1 and sequesters it to the GA, where it negatively modulates the Ras/Raf/MEK/ERK signaling pathway in tumor models. Studies suggest that suppression of the ERK pathway can alleviate OGD/R-induced cell apoptosis. However, whether PAQR3 has potential effects on ischemic stroke and the underlying mechanism(s) remain unexplored. The current study is the first to show that PAQR3 was significantly downregulated in mouse neuroblastoma (N2A) cells upon OGD/R exposure, both at the mRNA and protein levels. Compared to that in controls, the mRNA level of PAQR3 began to decline at 0 h (0 h) after reperfusion, while the protein level began to decline at 4 h. Furthermore, overexpression of PAQR3 reduced OGD/R-induced apoptosis. The mRNA and protein levels of total ERK1 and ERK2 were unaltered, while activated p-ERK1 and p-ERK2 were decreased in N2A cells transfected with a PAQR3 expression vector after OGD for 4 h plus 24 h of reperfusion. Collectively, these data indicated that increased PAQR3 expression protected against OGD/R-induced apoptosis possibly by inhibiting the ERK signaling pathway. Therefore, PAQR3 might be a new attractive target in the treatment of OGD/R insult, and the underlying mechanism will pave the way for its potential experimental and clinical application.

Hydrogen-rich saline protects rat from oxygen glucose deprivation and reperusion-induced apoptosis through VDAC1 via Bcl-2.

BACKGROUND: Hydrogen is received as an inert gas that thought to be non-functional in vivo previously. Recently, emerging evidences showed that in ischemia/reperfusion (IR) condition, hydrogen reduced cellular reactive oxygen species (ROS) production and ameliorated cell apoptosis. However, the underlying mechanism of hydrogen on IR-induced apoptosis remains elusive. Here we tried to unravel the mode of action of hydrogen with rat adrenal medulla cell line PC-12 in vitro. METHODS: The mitochondrial functions before and after oxygen glucose deprivation and reperfusion (OGD/RP) were determined with corresponding dyes. The expression of Bcl-2, Bax, VDAC1, cytochrome c and caspase 9 was detected using qRT-PCR and Western Blotting method. Then Bcl-2 inhibitor, AB-199, was applied to investigate the role of Bcl-2 in OGD/RP-induced cell apoptosis. Finally, we manipulated the expression of VDAC1 with plasmids transfection to understand the effects of VDAC1 on Bcl-2-mediated anti-apoptosis in OGD/RP. RESULTS: In this study, we demonstrated that hydrogen-rich saline (HRS) reduced OGD/RP-mediated neuronal loss by stimulating the expression of Bcl-2, which suppressed the activity of VDAC1. Consequently, HRS maintained the mitochondrial functions, restrained the release of cytochrome c and caspase 9 activation, resulting in ameliorated cell viability. CONCLUSIONS: HRS ameliorated OGD/RP-induced PC-12 cell apoptosis and provided a novel treatment option for ischemia.

HspB8 mediates neuroprotection against OGD/R in N2A cells through the phosphoinositide 3-kinase/Akt pathway.

In a previous study, we found that Heat shock protein B8 (HspB8) overexpression could prevent the apoptosis and reduced cell viability induced by OGD/R and showed that the neuroprotective effect of HspB8 was mediated by inhibition of the mitochondrial apoptotic pathway. In recent study, HspB8 has been shown to protect the heart against ischemia/reperfusion (I/R) injury via activation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. However, whether this protective effect applied to brain I/R injury remained unexplored. To further test the mechanism of HspB8's effects in brain, we used oxygen-glucose deprivation followed by reperfusion (OGD/R), an in vitro model of ischemia to examine the involvement of PI3K/Akt signaling by treating mouse neuroblastoma cells (N2A cells) (untransfected or transfected with an HspB8 expression vector) with the PI3K inhibitor LY294002 before OGD/R. Our results revealed that the apoptosis-suppressing effect of HspB8 was mediated by the PI3K/Akt pathway. Therefore, HspB8 protected the N2A cells against OGD/R insult, possibly by activating the PI3K/Akt signaling pathway.

GOLPH3 Mediated Golgi Stress Response in Modulating N2A Cell Death upon Oxygen-Glucose Deprivation and Reoxygenation Injury.

Increasing evidence implicating that the organelle-dependent initiation of cell death merits further research. The evidence also implicates Golgi as a sensor and common downstream-effector of stress signals in cell death pathways, and it undergoes disassembly and fragmentation during apoptosis in several neurological disorders. It has also been reported that during apoptotic cell death, there is a cross talk between ER, mitochondria, and Golgi. Thus, we hypothesized that Golgi might trigger death signals during oxidative stress through its own machinery. The current study found that GOLPH3, an outer membrane protein of the Golgi complex, was significantly upregulated in N2A cells upon oxygen-glucose deprivation and reoxygenation (OGD/R), positioning from the compact perinuclear ribbon to dispersed vesicle-like structures throughout the cytoplasm. Additionally, elevated GOLPH3 promoted a stress-induced conversion of the LC3 subunit I to II and reactive oxygen species (ROS) production in long-term OGD/R groups. The collective data indicated that GOLPH3 not only acted as a sensor of Golgi stress for its prompt upregulation during oxidative stress but also as an initiator that triggered and propagated specific Golgi stress signals to downstream effectors. This affected ROS production and stress-related autophagy and finally controlled the entry into apoptosis. The data also supported the hypothesis that the Golgi apparatus could be an ideal target for stroke, neurodegenerative diseases, or cancer therapy through its own functional proteins.

Ischemic postconditioning regulates cardiomyocyte autophagic activity following ischemia/reperfusion injury.

Ischemic postconditioning (IPostC) is a promising protective mechanism for combating reperfusion injury. However, the role of autophagy in the protective effects of IPostC and the associated signaling pathways have remained to be elucidated. Male Sprague Dawley rats were subjected to 30 min ischemia and 1, 2, 3, 6, 12 and 24 h of reperfusion, with or without IPostC treatment. Autophagic flux was evaluated by detecting mRNA and protein expression levels of microtubule associated protein 1 light chain 3 and p62. Phosphorylated (p)-P70S6 kinase (P70S6K), p-adenosine monophosphate-activated kinase (AMPK) and Beclin 1 protein levels were measured by western blot analysis. Myocardial infarct size was measured using staining with Evans blue dye and myocardial apoptosis was evaluated by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling staining. Autophagic activity was observed to be inhibited within the first hour of reperfusion, increased during 2-6 h and reduced from 12-24 h following IPostC compared with reperfusion without IPostC. Inhibition of autophagy by chloroquine significantly reversed the effects of IPostC on myocardial infarct size and the levels of apoptosis. IPostC significantly increased Beclin 1 levels, inhibited AMPK activation and increased P70S6K activation within the first hour compared with reperfusion without IPostC. IPostC attenuated the upregulation of Beclin 1 levels, increased AMPK activation and reduced P70S6K activation between 2 and 12 h, and subsequently exerted the opposite effects on these molecules between 12 and 24 h. IPostC was demonstrated to regulate autophagic activity in a time­dependent manner. The Beclin 1 and AMPK-mammalian target of rapamycin signaling pathways are suggested to be involved in the regulation of IPostC in autophagy.

HspB8 is neuroprotective during oxygen glucose deprivation and reperfusion.

Heat shock protein B8 (HspB8) is a chaperone protein that is highly and constitutively expressed in the brain, cardiac tissue and many other organs. Recently, it has been shown that HspB8 can enhance cardiac function and render cardioprotection. However, the potential benefits of HspB8 action on ischemic stroke and the underlying mechanism(s) are largely unknown. To investigate whether HspB8 exerts protective effects on in vitro ischemia/ reperfusion (I/R) injury, mouse neuroblastoma cells were subjected to oxygen-glucose deprivation and reoxygenation (OGD/R). At first, we investigated and described the HspB8 expression and distribution in N2A cells exposed to OGD/R. Expressions of HspB8 were upregulated in mouse N2A cells after OGD/R, both at mRNA and protein levels. The level of HspB8 began increased after the OGD/R and peaked at 12 hour (12h) after the reperfusion, then declined at 24-hour time points, however, the level of HspB8 was still significantly increased compared to controls. Immunofluorescence analysis revealed that the expressed HspB8 was constitutively localized in the cytoplasm and at the periphery of the nucleus. Nuclear HspB8 levels increased after OGD/R compared with levels in the control, beginning as early as 4h reperfusion, the most conspicuous nuclear HspB8 staining was observed after 24h of reperfusion. Furthermore, overexpression of HspB8 reduced OGD/R -induced apoptosis by reducing the release of cytochrome c from mitochondria to cytosol. In conclusion, our data demonstrated that increased HspB8 expression and its nuclear shift in mouse N2A neuroblastoma cells protected against I/R injury, resulting in reduced apoptosis with the decrease of the release of cytochrome c from mitochondria to cytosol. Therefore, HspB8 might play a fundamental role in opposing and alleviating I/R injury in primary myocardial cells, and it may constitute a new therapeutic target for cerebral ischemic diseases.