Injury/ischemia-induced stem cells: up-to-date knowledge and future perspectives for neural regeneration

Brain injuries like ischemic stroke induce endogenous stem cell production. Although the precise traits of stem cells in pathological brains remain unclear, we previously demonstrated that injury/ischemia-induced stem cells(iSCs)are present in the post-stroke mouse(Nakagomi et al.,2009)and human brains(Beppu et al.,2019).

Exercise preconditioning alleviates ischemia-induced memory deficits by increasing circulating adiponectin

Cerebral ischemia is a major health risk that requires preventive approaches in addition to drug therapy.Physical exercise enhances neurogenesis and synaptogenesis,and has been widely used for functional rehabilitation after stroke.In this study,we determined whether exercise training before disease onset can alleviate the severity of cerebral ischemia.We also examined the role of exercise-induced circulating factors in these effects.Adult mice were subjected to 14 days of treadmill exercise training before surgery for middle cerebral artery occlusion.We found that this exercise pre-conditioning strategy effectively attenuated brain infarct area,inhibited gliogenesis,protected synaptic proteins,and improved novel object and spatial memory function.Further analysis showed that circulating adiponectin plays a critical role in these preventive effects of exercise.Agonist activation of adiponectin receptors by Adipo Ron mimicked the effects of exercise,while inhibiting receptor activation abolished the exercise effects.In summary,our results suggest a crucial role of circulating adiponectin in the effects of exercise pre-conditioning in protecting against cerebral ischemia and supporting the health benefits of exercise.

Endoplasmic reticulum stress and autophagy in cerebral ischemia/reperfusion injury:PERK as a potential target for intervention

Several studies have shown that activation of unfolded protein response and endoplasmic reticulum(ER)stress plays a crucial role in severe cerebral ischemia/reperfusion injury.Autophagy occurs within hours after cerebral ischemia,but the relationship between ER stress and autophagy remains unclear.In this study,we established experimental models using oxygen-glucose deprivation/reoxygenation in PC12 cells and primary neurons to simulate cerebral ischemia/reperfusion injury.We found that prolongation of oxygen-glucose deprivation activated the ER stress pathway protein kinase-like endoplasmic reticulum kinase(PERK)/eukaryotic translation initiation factor 2 subunit alpha(e IF2α)-activating transcription factor 4(ATF4)-C/EBP homologous protein(CHOP),increased neuronal apoptosis,and induced autophagy.Furthermore,inhibition of ER stress using inhibitors or by si RNA knockdown of the PERK gene significantly attenuated excessive autophagy and neuronal apoptosis,indicating an interaction between autophagy and ER stress and suggesting PERK as an essential target for regulating autophagy.Blocking autophagy with chloroquine exacerbated ER stress-induced apoptosis,indicating that normal levels of autophagy play a protective role in neuronal injury following cerebral ischemia/reperfusion injury.Findings from this study indicate that cerebral ischemia/reperfusion injury can trigger neuronal ER stress and promote autophagy,and suggest that PERK is a possible target for inhibiting excessive autophagy in cerebral ischemia/reperfusion injury.

A matrix metalloproteinase-responsive hydrogel system controls angiogenic peptide release for repair of cerebral ischemia/reperfusion injury

Vascular endothelial growth factor and its mimic peptide KLTWQELYQLKYKGI(QK)are widely used as the most potent angiogenic factors for the treatment of multiple ischemic diseases.However,conventional topical drug delivery often results in a burst release of the drug,leading to transient retention(inefficacy)and undesirable diffusion(toxicity)in vivo.Therefore,a drug delivery system that responds to changes in the microenvironment of tissue regeneration and controls vascular endothelial growth factor release is crucial to improve the treatment of ischemic stroke.Matrix metalloproteinase-2(MMP-2)is gradually upregulated after cerebral ischemia.Herein,vascular endothelial growth factor mimic peptide QK was self-assembled with MMP-2-cleaved peptide PLGLAG(TIMP)and customizable peptide amphiphilic(PA)molecules to construct nanofiber hydrogel PA-TIMP-QK.PA-TIMP-QK was found to control the delivery of QK by MMP-2 upregulation after cerebral ischemia/reperfusion and had a similar biological activity with vascular endothelial growth factor in vitro.The results indicated that PA-TIMP-QK promoted neuronal survival,restored local blood circulation,reduced blood-brain barrier permeability,and restored motor function.These findings suggest that the self-assembling nanofiber hydrogel PA-TIMP-QK may provide an intelligent drug delivery system that responds to the microenvironment and promotes regeneration and repair after cerebral ischemia/reperfusion injury.

Elevated Platelet Activating Factor Level in Ischemia-Related Arrhythmia and Its Electrophysiological Effect on Myocardium

Objective The mechanism through which platelet activating factor （PAF） induces cardiac electrical activity and arrhythmia is not well understood and previous studies have suggested a potential involvement of ion channels in its action. The present study was aimed to clarify the role of PAF in fatal arrhythmias following acute myocardia infarction （AMI） and the underlying mechanism. Methods （1） Blood PAF levels were measured among 72 AMI patients at the time of diagnosis with AMI and 48 h later, and their electrocardiogram （ECG） was recorded continuously. （2） Ischemia simulation and surface electrocardiogram were conducted in 20 pigs and their PAF levels were measured. （3） PAF perfusion and standard microelectrode recording were performed on guinea pig papillarymuscles. Results In both humans and pigs, elevated PAF levels were detected in AMI and simulated ischemia, respectively, and even higher PAF levels were found when fatal arrhythmias occurred. In guinea pig myocardium, PAF induced a shortening of action potential duration at 90% level of repolarization （APD 90 ）under non-ischemic conditions and a more pronounced shortening under early simulated ischemic conditions. Conclusion AMI and ischemia are associated with increased PAF levels in humans and pigs, which are further raised when fatal arrhythmia follows. The effects of PAF on the myocardium may be mediated by multiple ion channels.

Effect of protective myocardium by allitridum from decreasing apoptosis in rats with ischemia/reperfusion injury

Objective: Previous studies have shown t hat allitridum can protect myocardium from ischemia/reperfusion (I/R) injury, bu t whether allitridum had the effect of anti-apoptosis is unclear. The aim of th is study was to investigate whether allitridum had the effects of pharmacologica l preconditioning and decreasing myocardium apoptosis after ischemic insult. Methods: Pentobarbital sodium-anesthetized Sprague-Dawley (SD) rats underwent 30 min of left anterior descending (LAD) coronary occlusion foll owed by 120 min of reperfusion. Thirty-six rats were divided into three groups randomly: Control group, I/R group and allitridum (G) group. The control and I/R groups with saline, G group with allitridum were administrated 24 h before oper ation. Control group underwent only sham operation; the other two groups underwe nt I/R operation. Infarcted size (IS/AAR %) was measured in I/R and G groups. Ma londialdehyde (MDA), Creatine kinase isoenzyme-MB (CK-MB ), Superoxide dismuta se (SOD)and the apoptosis index (AI) by TUNEL staining were measured in each gro up. In addition, DNA fragmentation by agarose gel electrophoresis was conducted on DNA isolated from these groups. Results: Allitridum p retreatm ent decreased the infarcted size compared with I/R group in IS/ AAR%[(21.85±1. 49)% vs. ( 44.65±4.65)%, P<0.01], CK-MB [(986.40±94.01) vs. (2044.2 5±1 07.28) U/L, P<0.01] and MDA [(3.26±0.35) vs. (4.96±0.46) nmol/mg pro, P<0.01], and SOD level in G group was higher than that of I/R group [(140 .20±12.89)vs. (73.16±11.22) U/mg pro, P<0.01]. AI of I/R group was highe r than that of G group [(13.99±3.05)% vs. (6.97±1.23)%, P<0.01], which was consistent with that in DNA fragmentation by agarose gel electrophoresis. Conclusion: This study indicated that allitridum had the effect of protecting myocardium against I/R injury and decreasing infarcted zone. The e ffect was probably through decreasing myocardium apoptosis in I/R injury.

西加盆地Cardium组薄砾岩储层水驱可行性分析

为明确西加盆地Cardium组Cardium A薄砾岩油藏水驱开发潜力,基于岩心观察、压汞及相渗实验、现场注水试验数据和油藏数值模拟等,划分储层类型,分析油藏水驱开发效果。结果表明:西加盆地Cardium组Cardium A薄砾岩储层类型可划分为Ⅰ类纯净砾岩和Ⅱ类含杂质砾岩,油井产能受控于砾岩储层厚度和储层类型;砾岩储层非均质发育、平面岩相相变快,现场注水无法形成连片有效的水驱通道,油井动态响应呈快速水窜型和轻微受效型;水驱开发数值模拟显示温和注水方案的整体增油效果优于强化注水方案的,注水方案相比不注水方案轻微增油,Cardium A薄砾岩油藏的水驱增油可行性较低。该结果为其他同类型油藏注水开发提供参考。

Development of a new cerebral ischemia reperfusion model of Mongolian gerbils and standardized evaluation system

Background:The Mongolian gerbil is an excellent laboratory animal for preparing the cerebral ischemia model due to its inherent deficiency in the circle of Willis.However,the low incidence and unpredictability of symptoms are caused by numerous complex variant types of the circle.Additionally,the lack of an evaluation system for the cer-ebral ischemia/reperfusion(I/R)model of gerbils has shackled the application of this model.Methods:We created a symptom-oriented principle and detailed neurobehavioral scoring criteria.At different time points of reperfusion,we analyzed the alteration in locomotion by rotarod test and grip force score,infarct volume by triphenyltetrazo-lium chloride(TTC)staining,neuron loss using Nissl staining,and histological charac-teristics using hematoxylin-eosin(H&E)straining.Results:With a successful model rate of 56%,32 of the 57 gerbils operated by our method harbored typical features of cerebral I/R injury,and the mortality rate in the male gerbils was significantly higher than that in the female gerbils.The suc-cessfully prepared I/R gerbils demonstrated a significant reduction in motility and grip strength at 1 day after reperfusion;formed obvious infarction;exhibited typi-cal pathological features,such as tissue edema,neuronal atrophy and death,and vacuolated structures;and were partially recovered with the extension of reperfu-sion time.Conclusion:This study developed a new method for the unilateral common carotid artery ligation I/R model of gerbil and established a standardized evaluation system for this model,which could provide a new cerebral I/R model of gerbils with more practical applications.

Changes of Monophasic Action Potential Duration and Effective Refractory Period of Three Layers Myocardium of Canine during Acute Ischemia in Vivo

Summary： The effect of acute ischemia on the electrophysiological characteristics of the three layers myocardium of canine in vivo was investigated. Twelve canines were divided into two groups randomly： acute ischemia （AI） group and sham operation （SO） group. By using the monophasic action potential （MAP） technique, MAP and effective refractory period （ERP） of the three layers myocardium were measured by specially designed plunge needle electrodes and the transmural dispersion of repolarization （TDR） and transmural dispersion of ERP （TDE） were analyzed. The results showed that in the AI group, MAP duration （MAPD） was shortened from 201.67±21.42 ms to 169.50±13.81 ms （P〈0.05）, but ERP prolonged to varying degrees and TDE increased during ischemia. In the SO group, MAPD and ERP did not change almost. Among of the three layers myocardium of canine, MAPD was coincident in two groups. It was concluded that during acute ischemia, MAPD was shortened sharply, but there was no significant difference among of the three layers myocardium. The prolonged ERP was concomitant with increased TDE during acute ischemia, which may play an important role in the occurrence of arrhythmias induced by acute ischemia. These findings may have important implications in arrhythmogenesis.

Treatment with β-sitosterol ameliorates the effects of cerebral ischemia/reperfusion injury by suppressing cholesterol overload, endoplasmic reticulum stress, and apoptosis

β-Sitosterol is a type of phytosterol that occurs naturally in plants.Previous studies have shown that it has anti-oxidant,anti-hyperlipidemic,anti-inflammatory,immunomodulatory,and anti-tumor effects,but it is unknown whetherβ-sitosterol treatment reduces the effects of ischemic stroke.Here we found that,in a mouse model of ischemic stroke induced by middle cerebral artery occlusion,β-sitosterol reduced the volume of cerebral infarction and brain edema,reduced neuronal apoptosis in brain tissue,and alleviated neurological dysfunction;moreover,β-sitosterol increased the activity of oxygen-and glucose-deprived cerebral cortex neurons and reduced apoptosis.Further investigation showed that the neuroprotective effects ofβ-sitosterol may be related to inhibition of endoplasmic reticulum stress caused by intracellular cholesterol accumulation after ischemic stroke.In addition,β-sitosterol showed high affinity for NPC1L1,a key transporter of cholesterol,and antagonized its activity.In conclusion,β-sitosterol may help treat ischemic stroke by inhibiting neuronal intracellular cholesterol overload/endoplasmic reticulum stress/apoptosis signaling pathways.

Effect of electroacupuncture "Shenmen" on the expression of cAMP and cGMP in the myocardium, hippocampus and serum of rats with acute myocardial ischemia

Objective:Discussion on the protectiion of electroacupuncture"Shenmen"on heart and brain injury induced by acute myocardial ischemia in rats from the perspective of the expression of cyclic adenosine monophosphate(cAMP)and cyclic guanosine monophosphate(cGMP).Methods:Thirty male SD rats were randomly divided into normal group,model group,and electroacupuncture group.The electrocardiogram was recorded by the Powerlab 8-lead physiological recording system.The left anterior descending coronary artery was ligated to replicate the rat myocardial ischemia model.The acupuncture group was treated with electroacupuncture on the second day after the model was replicated.After the last electroacupuncture treatment,rat myocardium,hippocampus tissue and abdominal aortic blood were collected,and enzyme-linked immunosorbent assay was used to detect the levels of cAMP and cGMP in myocardium,hippocampus tissue and serum content.Results:Compared with the normal group,the cAMP content in the myocardial tissue of the model group was significantly increased,and the cAMP content in the hippocampus tissue and serum was significantly reduced;compared with the model group,the cAMP content in the myocardial tissue of the electroacupuncture group was decreased,and the hippocampus tissue Compared with the normal group,the content of cGMP in the myocardial tissue and serum of the model group increased,and the content of cGMP in the hippocampus decreased.Compared with the model group,the content of cGMP in the hippocampus of the electroacupuncture group was increased.The cGMP content increased,the serum cGMP content was significantly reduced,and the difference in the cGMP content in myocardial tissue was not statistically significant.Conclusion:Electroacupuncture at"Shenmen"acupoint can significantly improve the expression of cAMP,cGMP and myocardial cAMP in the serum and hippocampus of model rats with acute myocardial ischemia-induced heart and brain injury,but has a lower effect on myocardial cGMP content.

Effects of electroacupuncture of acupoints of the neiguan and ximen on ischemic myocardium energy metabolism with acute myocardial ischemia rats

Objective:To observe the effect of Electroacupuncture of Acupoints of the Neiguan(PC6)and Ximen(PC4)on its myocardial energy metabolism with acute myocardial ischemia rats caused by coronary artery ligation.Methods:Forty standard Spargue-Dawely(SD)rats were divided into four groups randomly,namely,group of Neiguan,group of Ximen,model group,sham group.The group of rats of myocardial ischemia were induced by coronary ligation,and the model rat of acute myocardial ischemia was prepared.The sham group had no ligation of the needle.After anesthesia was awakened,acupuncture was applied bilateral at Neiguan and Ximen of the group of Neiguan and Ximen,once a day at a fixed time for 14 days.The rats of model group and the sham group were not given acupunctured,but use the samely methods of Neiguan and Ximen groups to grap the rats at the same time everyday.After 14 days the experiment was over,observed the pathological changes of myocardial tissue by HE staining,detected the levels of free fatty acid(FFA),adenosine triphosphate(ATP)content,and the activities of Na^(+)-K^(+)-ATPase according to the reagents´demand.Results:Pathological results showed that acupuncuted at Neiguan and Ximen could improve the ischemic cardiomyocyte injury.Compared with the sham group,the levels of FFA in model group were increased(p<0.01),the levels of ATP,the activities of Na^(+)-K^(+)-ATPase were all decreased(p<0.01);Compared with the model group,the levels of FFA were decreased(p<0.05,p<0.01),the levels of ATP,the activities of Na^(+)-K^(+)-ATPase were improved.Conclusion:Acupuncturing at the Pericardium Meridian can alleviate the cell injury by myocardial ischemia,and also can improve the myocardial energetic metabolism in acute myocardial ischemia.

The action mechanism by which C1q/tumor necrosis factor-related protein-6 alleviates cerebral ischemia/reperfusion injury in diabetic mice

Studies have shown that C1q/tumor necrosis factor-related protein-6 (CTRP6) can alleviate renal ischemia/reperfusion injury in mice. However, its role in the brain remains poorly understood. To investigate the role of CTRP6 in cerebral ischemia/reperfusion injury associated with diabetes mellitus, a diabetes mellitus mouse model of cerebral ischemia/reperfusion injury was established by occlusion of the middle cerebral artery. To overexpress CTRP6 in the brain, an adeno-associated virus carrying CTRP6 was injected into the lateral ventricle. The result was that oxygen injury and inflammation in brain tissue were clearly attenuated, and the number of neurons was greatly reduced. In vitro experiments showed that CTRP6 knockout exacerbated oxidative damage, inflammatory reaction, and apoptosis in cerebral cortical neurons in high glucose hypoxia-simulated diabetic cerebral ischemia/reperfusion injury. CTRP6 overexpression enhanced the sirtuin-1 signaling pathway in diabetic brains after ischemia/reperfusion injury. To investigate the mechanism underlying these effects, we examined mice with depletion of brain tissue-specific sirtuin-1. CTRP6-like protection was achieved by activating the sirtuin-1 signaling pathway. Taken together, these results indicate that CTRP6 likely attenuates cerebral ischemia/reperfusion injury through activation of the sirtuin-1 signaling pathway.

Cav3.2 channel regulates cerebral ischemia/reperfusion injury:a promising target for intervention

Calcium influx into neurons triggers neuronal death during cerebral ischemia/reperfusion injury.Various calcium channels are involved in cerebral ischemia/reperfusion injury.Cav3.2 channel is a main subtype of T-type calcium channels.T-type calcium channel blockers,such as pimozide and mibefradil,have been shown to prevent cerebral ischemia/reperfusion injury-induced brain injury.However,the role of Cav3.2 channels in cerebral ischemia/reperfusion injury remains unclear.Here,in vitro and in vivo models of cerebral ischemia/reperfusion injury were established using middle cerebral artery occlusion in mice and high glucose hypoxia/reoxygenation exposure in primary hippocampal neurons.The results showed that Cav3.2 expression was significantly upregulated in injured hippocampal tissue and primary hippocampal neurons.We further established a Cav3.2 gene-knockout mouse model of cerebral ischemia/reperfusion injury.Cav3.2 knockout markedly reduced infarct volume and brain water content,and alleviated neurological dysfunction after cerebral ischemia/reperfusion injury.Additionally,Cav3.2 knockout attenuated cerebral ischemia/reperfusion injury-induced oxidative stress,inflammatory response,and neuronal apoptosis.In the hippocampus of Cav3.2-knockout mice,calcineurin overexpression offset the beneficial effect of Cav3.2 knockout after cerebral ischemia/reperfusion injury.These findings suggest that the neuroprotective function of Cav3.2 knockout is mediated by calcineurin/nuclear factor of activated T cells 3 signaling.Findings from this study suggest that Cav3.2 could be a promising target for treatment of cerebral ischemia/reperfusion injury.

Antioxidative effect of peroxiredoxin-3 in the rat myocardium exposed to renal ischemia-reperfusion injury

Background:Peroxiredoxin-3(Prx-3)is known to be involved in the clearance of cellular hydrogen peroxide and plays an important role in protecting the myocardial tissue against damage of oxidative stress.However,the role of Prx-3 in protecting the myocardial tissue against renal ischemia/reperfusion(I/R)-induced myocardial injury(RI/RMI)remains unknown.We aimed to examine the antioxidative effect of Prx-3 using a rat RI/RMI model in an attempt to find a new approach to the prevention and treatment of myocardial injury induced by renal I/R.Methods:A RI/RMI rat model was established to detect the renal histopathology and renal functions by hematoxylin-eosin staining staining and commercially available assay kits.The myocardial antioxidant activity and the expressions of mRNA and protein of Prx-3 in the myocardial tissue were measured by real-time polymerase chain reaction and Western blotting assay,respectively.Results:Compared with the normal and control groups,the serum level of blood urea nitrogen and serum creatinine was significantly increased in the I/R group(P<0.05).Histopathological changes in the kidneys were also more obvious,including glomerular cystic and renal interstitial hemorrhage,renal tubular epithelial cell edema,and tubular type formation.The mRNA and protein expressions of Prx-3 were increased significantly in the RI/MRI rat model as compared with those in the normal and control groups.Conclusion:Oxidative damage occurred in the remote myocardium after renal I/R and Prx-3 was able to enhance the self-regulatory ability of the myocardium against damage from oxidative stress after RI/MRI.

Homer1a reduces inflammatory response after retinal ischemia/reperfusion injury

Elevated intraocular pressure(IOP)is one of the causes of retinal ischemia/reperfusion injury,which results in NRP3 inflammasome activation and leads to visual damage.Homerla is repo rted to play a protective role in neuroinflammation in the cerebrum.However,the effects of Homerla on NLRP3inflammasomes in retinal ischemia/reperfusion injury caused by elevated IOP remain unknown.In our study,animal models we re constructed using C57BL/6J and Homer1^(flox/-)/Homerla^(+/-)/Nestin-Cre^(+/-)mice with elevated IOP-induced retinal ischemia/repe rfusion injury.For in vitro expe riments,the oxygen-glucose deprivation/repe rfusion injury model was constructed with M uller cells.We found that Homerla ove rexpression amelio rated the decreases in retinal thickness and Muller cell viability after ischemia/reperfusion injury.Furthermore,Homerla knockdown promoted NF-κB P65^(Ser536)activation via caspase-8,NF-κB P65 nuclear translocation,NLRP3 inflammasome formation,and the production and processing of interleukin-1βand inte rleukin-18.The opposite results we re observed with Homerla ove rexpression.Finally,the combined administration of Homerla protein and JSH-23 significantly inhibited the reduction in retinal thickness in Homer1^(flox/-)Homer1a^(+/-)/Nestin-Cre^(+/-)mice and apoptosis in M uller cells after ischemia/reperfusion injury.Taken together,these studies demonstrate that Homer1a exerts protective effects on retinal tissue and M uller cells via the caspase-8/NF-KB P65/NLRP3 pathway after I/R injury.

Natural Products Improve Organ Microcirculation Dysfunction Following Ischemia/Reperfusion-and Lipopolysaccharide-Induced Disturbances:Mechanistic and Therapeutic Views

Microcirculatory disturbances are complex processes caused by many factors,including abnormal vasomotor responses,decreased blood flow velocity,vascular endothelial cell injury,altered leukocyte and endothelial cell interactions,plasma albumin leakage,microvascular hemorrhage,and thrombosis.These disturbances involve multiple mechanisms and interactions among mechanisms that can include energy metabolism,the mitochondrial respiratory chain,oxidative stress,inflammatory factors,adhesion molecules,the cytoskeleton,vascular endothelial cells,caveolae,cell junctions,the vascular basement membrane,neutrophils,monocytes,and platelets.In clinical practice,aside from drugs that target abnormal vasomotor responses and platelet adhesion,there continues to be a lack of multi-target drugs that can regulate the complex mechanistic links and interactions underlying microcirculatory disturbances.Natural products have demonstrated obvious positive therapeutic effects in treating ischemia/reperfusion(I/R)-and lipopolysaccharide(LPS)-induced microcirculatory disturbances.In recent years,numerous research papers on the improvement of microcirculatory function by natural products have been published in international journals.In 2008 and 2017,the first listed author of this review was invited to publish reviews in the journal of Pharmacology&Therapeutics on the improvement of microcirculatory disturbances and organ injury induced by I/R using Salvia miltiorrhiza ingredients and other natural components of compounded Chinese medicine,respectively.This review systematically summarizes the effects,targets of action,and mechanisms of natural products regarding improving I/R-and LPSinduced microcirculatory disturbances and tissue injury.Based on this summary,scientific proposals are suggested for the discovery of new drugs to improve microcirculatory disturbances in disease.

PROTECTIVE EFFECTS OF ERYTHROPOIETIN ON MYO-CARDIUM AGAINST ISCHEMIA-REPERFUSION INJURY

Objective To explore the protective effects of erythropoietin （EPO） on myocardium against ischemia-reperfusion injury （ IRI）. Methods The Langendorff model of isolated rat heart was set up and a 3-stage protocol was performed： 20 min stabilization, 30 min global ischemia, and 120 min reperfusion. Sixty SD rats were randomly divided into sham group, ischemia-reperfusion group （I/R group ） and EPO treated group （ EPO group）. Heart rate （ HR）, left ventricular developed pressure （ LVDP）, the first derivative （ △dp/dt max） and coronary flow （CF） were recorded at the 20th minute of stabilization and the 120th minute of reperfusion. Lactate dehydrogenase （LDH） and creatine phosphokinase （CK） in the coronary effluent at the 60th minute of reperfusion , the levels of myocardial nuclear factor-kappa B （NF-KB） and the myocardial content of tumor necrosis factor-α （TNF-α） ,interleukin-lβ （1L-lβ） were measured at the end of reperfusion. Results No statistically significant differences were observed on the aspect of hemodynamic parameters among the groups at the 20th minute of stabilization, but at the 120th minute of reperfusion, the recovery ratio of EPO group was higher than I/R group （P 〈0. 05）. LDH and CK in the coronary effluent, the levels of myocardial NF-KB and TNF-α,IL-lβ expression in EPO group were significantly lower than those in I/ R group, but higher than sham group （ P 〈 0. 05 ）. Conclusion EPO has protective effects on myocardium against 1RI possibly through the mechanism of relieving the myocardial inflanmtatory reaction by regulating the activation of NF-KB and then decreasing the expression of proinflammatory factors TNF-α and IL-lβ.

Challenging situation of coronary artery anomaly associated with ischemia and/or risk of sudden death

Coronary artery anomaly is known as one of the causes of angina pectoris and sudden death and is an important clinical entity that cannot be overlooked.The incidence of coronary artery anomalies is as low as 1%-2%of the general population,even when the various types are combined.Coronary anomalies are practically challenging when the left and right coronary ostium are not found around their normal positions during coronary angiography with a catheter.If there is atherosclerotic stenosis of the coronary artery with an anomaly and percutaneous coronary intervention(PCI)is required,the suitability of the guiding catheter at the entrance and the adequate back up force of the guiding catheter are issues.The level of PCI risk itself should also be considered on a caseby-case basis.In this case,emission computed tomography in the R-1 subtype single coronary artery proved that ischemia occurred in an area where the coronary artery was not visible to the naked eye.Meticulous follow-up would be crucial,because sudden death may occur in single coronary arteries.To prevent atherosclerosis with full efforts is also important,as the authors indicated admirably.

Cold ischemia time in liver transplantation:An overview

The standard approach to organ preservation in liver transplantation is by static cold storage and the time between the cross-clamping of a graft in a donor and its reperfusion in the recipient is defined as cold ischemia time(CIT).This simple definition reveals a multifactorial time frame that depends on donor hepatectomy time,transit time,and recipient surgery time,and is one of the most important donor-related risk factors which may influence the graft and recipient’s survival.Recently,the growing demand for the use of marginal liver grafts has prompted scientific exploration to analyze ischemia time factors and develop different organ preservation strategies.This review details the CIT definition and analyzes its different factors.It also explores the most recent strategies developed to implement each timestamp of CIT and to protect the graft from ischemic injury.