Cerebral resuscitation: state of the art, experimental approaches and clinical perspectives

Multi-Drug Cocktail Therapy Improves Survival and Neurological Function after Asphyxial Cardiac Arrest in Rodents

BACKGROUND

Cardiac arrest (CA) can lead to neuronal degeneration and death through various pathways, including oxidative, inflammatory, and metabolic stress. However, current neuroprotective drug therapies will typically target only one of these pathways, and most single drug attempts to correct the multiple dysregulated metabolic pathways elicited following cardiac arrest have failed to demonstrate clear benefit. Many scientists have opined on the need for novel, multidimensional approaches to the multiple metabolic disturbances after cardiac arrest. In the current study, we have developed a therapeutic cocktail that includes ten drugs capable of targeting multiple pathways of ischemia-reperfusion injury after CA. We then evaluated its effectiveness in improving neurologically favorable survival through a randomized, blind, and placebo-controlled study in rats subjected to 12 min of asphyxial CA, a severe injury model.

RESULTS

14 rats were given the cocktail and 14 received the vehicle after resuscitation. At 72 h post-resuscitation, the survival rate was 78.6% among cocktail-treated rats, which was significantly higher than the 28.6% survival rate among vehicle-treated rats (log-rank test; p = 0.006). Moreover, in cocktail-treated rats, neurological deficit scores were also improved. These survival and neurological function data suggest that our multi-drug cocktail may be a potential post-CA therapy that deserves clinical translation.

CONCLUSIONS

Our findings demonstrate that, with its ability to target multiple damaging pathways, a multi-drug therapeutic cocktail offers promise both as a conceptual advance and as a specific multi-drug formulation capable of combatting neuronal degeneration and death following cardiac arrest. Clinical implementation of this therapy may improve neurologically favorable survival rates and neurological deficits in patients suffering from cardiac arrest.

Palmitic acid methyl ester inhibits cardiac arrest-induced neuroinflammation and mitochondrial dysfunction

We previously discovered that palmitic acid methyl ester (PAME) is a potent vasodilator released from the sympathetic ganglion with vasoactive properties. Post-treatment with PAME can enhance cortical cerebral blood flow and functional learning and memory, while inhibiting neuronal cell death in the CA1 region of the hippocampus under pathological conditions (i.e. cerebral ischemia). Since mechanisms underlying PAME-mediated neuroprotection remain unclear, we investigated the possible neuroprotective mechanisms of PAME after 6 min of asphyxial cardiac arrest (ACA, an animal model of global cerebral ischemia). Our results from capillary-based immunoassay (for the detection of proteins) and cytokine array suggest that PAME (0.02 mg/kg) can decrease neuroinflammatory markers, such as ionized calcium binding adaptor molecule 1 (Iba1, a specific marker for microglia/macrophage activation) and inflammatory cytokines after cardiopulmonary resuscitation. Additionally, the mitochondrial oxygen consumption rate (OCR) and respiratory function in the hippocampal slices were restored following ACA (via Seahorse XF24 Extracellular Flux Analyzer) suggesting that PAME can ameliorate mitochondrial dysfunction. Finally, hippocampal protein arginine methyltransferase 1 (PRMT1) and PRMT8 are enhanced in the presence of PAME to suggest a possible pathway of methylated fatty acids to modulate arginine-based enzymatic methylation. Altogether, our findings suggest that PAME can provide neuroprotection in the presence of ACA to alleviate neuroinflammation and ameliorate mitochondrial dysfunction.

Comparison of Quantitative Characteristics of Early Post-resuscitation EEG Between Asphyxial and Ventricular Fibrillation Cardiac Arrest in Rats

BACKGROUND

Quantitative electroencephalogram (EEG) analysis has shown promising results in studying brain injury and functional recovery after cardiac arrest (CA). However, whether the quantitative characteristics of EEG, as potential indicators of neurological prognosis, are influenced by CA causes is unknown. The purpose of this study was designed to compare the quantitative characteristics of early post-resuscitation EEG between asphyxial CA (ACA) and ventricular fibrillation CA (VFCA) in rats.

METHODS

Thirty-two Sprague-Dawley rats of both sexes were randomized into either ACA or VFCA group. Cardiopulmonary resuscitation was initiated after 5-min untreated CA. Characteristics of early post-resuscitation EEG were compared, and the relationships between quantitative EEG features and neurological outcomes were investigated.

RESULTS

Compared with VFCA, serum level of S100B, neurological deficit score and brain histopathologic damage score were dramatically higher in the ACA group. Quantitative measures of EEG, including onset time of EEG burst, time to normal trace, burst suppression ratio, and information quantity, were significantly lower for CA caused by asphyxia and correlated with the 96-h neurological outcome and survival.

CONCLUSIONS

Characteristics of earlier post-resuscitation EEG differed between cardiac and respiratory causes. Quantitative measures of EEG not only predicted neurological outcome and survival, but also have the potential to stratify CA with different causes.

Brain injury following cardiac arrest: pathophysiology for neurocritical care

Cardiac arrest induces the cessation of cerebral blood flow, which can result in brain damage. The primary intervention to salvage the brain under such a pathological condition is to restore the cerebral blood flow to the ischemic region. Ischemia is defined as a reduction in blood flow to a level that is sufficient to alter normal cellular function. Brain tissue is highly sensitive to ischemia, such that even brief ischemic periods in neurons can initiate a complex sequence of events that may ultimately culminate in cell death. However, paradoxically, restoration of blood flow can cause additional damage and exacerbate the neurocognitive deficits in patients who suffered a brain ischemic event, which is a phenomenon referred to as “reperfusion injury.” Transient brain ischemia following cardiac arrest results from the complex interplay of multiple pathways including excitotoxicity, acidotoxicity, ionic imbalance, peri-infarct depolarization, oxidative and nitrative stress, inflammation, and apoptosis. The pathophysiology of post-cardiac arrest brain injury involves a complex cascade of molecular events, most of which remain unknown. Many lines of evidence have shown that mitochondria suffer severe damage in response to ischemic injury. Mitochondrial dysfunction based on the mitochondrial permeability transition after reperfusion, particularly involving the calcineurin/immunophilin signal transduction pathway, appears to play a pivotal role in the induction of neuronal cell death. The aim of this article is to discuss the underlying pathophysiology of brain damage, which is a devastating pathological condition, and highlight the central signal transduction pathway involved in brain damage, which reveals potential targets for therapeutic intervention.

One-year follow-up of neurological status of patients after cardiac arrest seen at the emergency room of a teaching hospital

Objective:

To describe neurological status and associated factors of survivors after cardiac arrest, upon discharge, and at 6 and 12 month follow-up.

Methods:

A cohort, prospective, descriptive study conducted in an emergency room. Patients who suffered cardiac arrest and survived were included. A one-year consecutive sample, comprising 285 patients and survivors (n=16) followed up for one year after discharge. Neurological status was assessed by the Cerebral Performance Category before the cardiac arrest, upon discharge, and at 6 and 12 months after discharge. The following factors were investigated: comorbidities, presence of consciousness upon admission, previous cardiac arrest, witnessed cardiac arrest, location, cause and initial rhythm of cardiac arrest, number of cardiac arrests, interval between collapse and start of cardiopulmonary resuscitation, and between collapse and end of cardiopulmonary resuscitation, and duration of cardiopulmonary resuscitation.

Results:

Of the patients treated, 4.5% (n=13) survived after 6 and 12 months follow-up. Upon discharge, 50% of patients remained with previous Cerebral Performance Category of the cardiac arrest and 50% had worsening of Cerebral Performance Category. After 6 months, 53.8% remained in the same Cerebral Performance Category and 46.2% improved as compared to discharge. After 12 months, all patients remained in the same Cerebral Performance Category of the previous 6 months. There was no statistically significant association between neurological outcome during follow-up and the variables assessed.

Conclusion:

There was neurological worsening at discharge but improvement or stabilization in the course of a year. There was no association between Cerebral Performance Category and the variables assessed.

A Review of Ancillary Tests in Evaluating Brain Death

The neurological determination of death (NDD) is primarily considered to be clinical. However, situations may arise where confounding factors make this clinical assessment difficult or impossible. As a result, ancillary tests have been developed in order to aid in the confirmation of brain death. As assessment of neuronal electrical activity; electroencephalography (EEG) is no longer recommended in this determination, tools assessing cerebral perfusion, as reflected by the presence or absence of cerebral blood flow (CBF), are the mainstay of NDD. The preferred ancillary test currently is Hexamethylpropylene amine oxime-single photon emission computed tomography (HMPAO SPECT) radionuclide angiography. When this is not available, or is equivocal, 4-vessel cerebral angiography can be used to determine the presence or absence of intracranial blood flow. However, as cerebral angiography has its own limitations, other techniques are sought by physicians in the Intensive Care and Neuro-intensive Care settings to replace cerebral angiography. In this article, we briefly review the history of diagnosis of brain death, pathophysiologic issues in making this determination, and currently available CBF imaging techniques, discussing each in turn with respect to their utility in the diagnosis of brain death.

[Saving lives with dispatcher-assisted resuscitation: importance of effective telephone instruction]

BACKGROUND

Survival rates after sudden cardiac arrest could be increased if bystanders could be encouraged to perform CPR until emergency services arrive. This should be initiated by the dispatcher at the emergency control facility who receives the call. For the first time the ERC guidelines of 2010 included instructions to be given to untrained rescuers by the dispatcher. Rapid recognition of cardiac arrest and initiation of emergency measures is assured by means of specific training for the dispatchers.

AIM

The aim of this investigation was to determine whether the time between an emergency call and beginning of cardiopulmonary resuscitation (CPR) could be shortened using a simple protocol and whether a relationship exists between the intensity of phone contact between dispatcher and caller and if this improves the results.

MATERIALS AND METHODS

In known cases of unconsciousness, group 1 (45 persons) received short CPR instructions via the phone, where the dispatcher was on the phone for continuous advice until emergency services arrived. Group 2 (45 persons) received identical phone instructions like group 1, but the phone call was terminated by the dispatcher after the information was provided. Group 3 (29 persons) only received instructions to start CPR.

RESULTS

On average, all test persons in group 1 started reanimation after 68.0 ± 33.5 s, in group 2 after 68.3 ± 25.2 s, and in group 3 after 64.9 ± 34.4 s. The compression frequency on average was 98.3/min in group 1, 84.8/min in group 2, and 85.2/min in group 3; therefore, all groups reached an average frequency of > 80/min. The correct compression depth was achieved by 47.8 % of test persons in group 1, by 44.2 % in group 2, and by 30.2 % in group 3. All volunteers felt well supported. Of the 90 people, 70 did not feel that they were missing instructions.

DISCUSSION

There were no significant differences between the groups regarding the target variables. The results show that already extremely short instructions or advice by the dispatcher to start CPR is sufficient to encourage bystanders to give assistance in an emergency. Continuous support over the phone does not appear to be necessary.

Expressional changes in cerebrovascular receptors after experimental transient forebrain ischemia

BACKGROUND

Global ischemic stroke is one of the most prominent consequences of cardiac arrest, since the diminished blood flow to the brain results in cell damage and sometimes permanently impaired neurological function. The post-arrest period is often characterised by cerebral hypoperfusion due to subacute hemodynamic disturbances, the pathophysiology of which are poorly understood. In two other types of stroke, focal ischemic stroke and subarachnoid hemorrhage, it has earlier been demonstrated that the expression of certain vasoconstrictor receptors is increased in cerebral arteries several days after the insult, a phenomenon that leads to increased contraction of cerebral arteries, reduced perfusion of the affected area and worsened ischemic damage. Based on these findings, the aim of the present study was to investigate if transient global cerebral ischemia is associated with upregulation of vasoconstrictive endothelin and 5-hydroxytryptamine receptors in cerebral arteries. Experimental transient forebrain ischemia of varying durations was induced in male wistar rats, followed by reperfusion for 48 hours. Neurological function was assessed daily by three different tests and cerebrovascular expression and contractile function of endothelin and 5-hydroxytryptamine receptors were evaluated by wire myography, immunohistochemistry and western blotting.

RESULTS

Transient forebrain ischemia induced neurological deficits as well as functional upregulation of vasoconstrictive ET(B) and 5-HT(1B) receptors in cerebral arteries supplying mid- and forebrain regions. No receptor upregulation was seen in arteries supplying the hindbrain. Immunohistochemical stainings and western blotting demonstrated expressional upregulation of these receptor subtypes in the mid- and forebrain arteries and confirmed that the receptors were located in the smooth muscle layer of the cerebral arteries.

CONCLUSIONS

This study reveals a new pathophysiological aspect of global ischemic stroke, namely expressional upregulation of vasoconstrictor receptors in cerebral arteries two days after the insult, which might contribute to cerebral hypoperfusion and delayed neuronal damage after cardiac arrest.

Resuscitation with hypertonic saline-dextran reduces serum biomarker levels and correlates with outcome in severe traumatic brain injury patients

In the treatment of severe traumatic brain injury (TBI), the choice of fluid and osmotherapy is important. There are practical and theoretical advantages to the use of hypertonic saline. S100B, neuron-specific enolase (NSE), and myelin-basic protein (MBP) are commonly assessed biomarkers of brain injury with potential utility as diagnostic and prognostic indicators of outcome after TBI, but they have not previously been studied in the context of fluid resuscitation. This randomized controlled trial compared serum concentrations of S100B, NSE, and MBP in adult severe TBI patients resuscitated with 250 mL of 7.5% hypertonic saline plus 6% dextran70 (HSD; n = 31) versus 0.9% normal saline (NS; n = 33), and examined their relationship with neurological outcome at discharge. Blood samples drawn on admission (<or=3 h post-injury), and at 12, 24, and 48 h post-resuscitation were assayed by ELISA for the selected biomarkers. Serial comparisons of biomarker concentrations were made by ANOVA, and relationships between biomarkers and outcome were assessed by multiple regression. On admission, mean (+/-SEM) S100B and NSE concentrations were increased 60-fold (0.73 +/- 0.08 microg/L) and sevenfold (37.0 +/- 4.8 microg/L), respectively, in patients resuscitated with NS, compared to controls (0.01 +/- 0.01 and 6.2 +/- 0.6, respectively). Compared with NS resuscitation, S100B and NSE were twofold and threefold lower in HSD-treated patients and normalized within 12 h. MBP levels were not significantly different from controls in either treatment arm until 48 h post-resuscitation, when a delayed increase (0.58 +/- 0.29 microg/L) was observed in NS-treated patients. Biomarkers were elevated in the patient group showing an unfavorable outcome. HSD-resuscitated patients with favorable outcomes exhibited the lowest serum S100B and NSE concentrations, while maximal levels were found in NS-treated patients with unfavorable outcomes. The lowest biomarker levels were seen in survivors resuscitated with HSD, while maximal levels were in NS-resuscitated patients with fatal outcome. Pre-hospital resuscitation with HSD is associated with a reduction in serum S100B, NSE, and MBP concentrations, which are correlated with better outcome after severe TBI.

Activation of liver X receptor reduces global ischemic brain injury by reduction of nuclear factor-kappaB

Recent studies have found that liver X receptors (LXRs) agonists decrease brain inflammation and exert neuroprotective effect. The aim of this study was to examine the mechanisms of action of liver X receptor agonist GW3965 against brain injury following global cerebral ischemia in the rat. The 48 male SD (Sprague-Dawley) rats were randomly partitioned into three groups: sham, global ischemia (4-vessel occlusion for 15 min; 4VO) treated with vehicle and global ischemia treated with GW3965 (20 mg/kg, via i.p. injection at 10 min after reperfusion). The functional outcome was determined by neurological evaluation at 24 h post ischemia and by testing rats in T maze at 3 and 7 days after reperfusion. The rats' daily body weight, incidence of seizures and 72 h mortality were also determined. After Nissl staining and TUNEL in coronal brain sections, the numbers of intact and damaged cells were counted in the CA1 sector of the hippocampus. The expression of phosphorylated inhibitor of kappaB (p-IkappaBalpha), nuclear factor-kappaB (NF-kappaB) subunit p65, and cyclo-oxygenase-2 (COX-2) were analyzed with Western blot at 12 h after reperfusion. GW3965 tended to reduce 72 h mortality and the incidence of post-ischemic seizures. GW3965-treated rats showed an improved neuronal survivability in CA1 and a significant increase in the percentage of spontaneous alternations detected in T-maze on day 7 after ischemia. GW3965-induced neuroprotection was associated with a significant reduction in nuclear translocation of NF-kB p65 subunit and a decrease in the hippocampal expression of NF-kB target gene, COX-2. LXR receptor agonist protects against neuronal damage following global cerebral ischemia. The mechanism of neuroprotection may include blockade of NF-kappaB activation and the subsequent suppression of COX-2 in the post ischemic brain.

Statins for post resuscitation syndrome

After sudden cardiac arrest, successful resuscitation and return of spontaneous circulation, a multi-faceted ischaemia/reperfusion related disorder develops. This condition now known as post resuscitation syndrome is characterised by marked increases in the inflammatory response and changes in coagulation profile and vascular reactivity. Additionally, the production of reactive oxygen species and activation of cytotoxic cascades of metabolism add to these injury mechanisms resulting in multiorgan perfusion deficits and dysfunction. Especially in the cerebrum these injuries may be the cause of significant morbidity and mortality. Recent evidence has shown that statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) exert numerous beneficial effects in cardiovascular diseases irrespective of the lipid status. Remarkably, these pleiotropic effects seem to extended beyond cardiovascular diseases such as immunomodulative and antioxidative properties. We hypothesised that administration of statins early in the post resuscitation phase would prove beneficial in the resuscitated patient via several pleiotropic effects. These include inhibition of excessive coagulation and inflammatory response, suppression of oxygen radical production and improved vascular reactivity. The discussed effects are mediated via multiple pathways activated in the cardiac arrest victim, to which statins have been shown to have a beneficial modulating effect in experimental settings and non-cardiac arrest patients. To test this hypothesis in clinical practice, a randomized, controlled trial with sufficient power and standardised post resuscitation treatment would be necessary. The generally good tolerance of statin therapy with minimal adverse effects would support this experiment, although a parenteral form of the drug to ensure adequate dosage might be a prerequisite.

Probing the molecular mechanisms of neuronal degeneration: importance of mitochondrial dysfunction and calcineurin activation

Cerebral injury is a critical aspect of the management of patients in intensive care. Pathological conditions induced by cerebral ischemia, hypoxia, head trauma, and seizure activity can result in marked residual impairment of cerebral function. We have investigated the potential mechanisms leading to neuronal cell death in pathological conditions, with the aim of discovering therapeutic targets and methods to minimize neuronal damage resulting from insults directed at the central nervous system (CNS). Over the years, deeper understanding of the mechanisms of neuronal cell death has indeed evolved, enabling clinical critical care management to salvage neurons that are at the brink of degeneration and to support recovery of brain function. However, no substantial breakthrough has been achieved in the quest to develop effective pharmacological neuroprotective therapy directed at tissues of the CNS. The current situation is unacceptable, and preservation of function and protection of the brain from terminal impairment will be a vital medical issue in the twenty-first century. To achieve this goal, it is critical to clarify the key mechanisms leading to neuronal cell death. Here, we discuss the importance of the calcineurin/immunophilin signal transduction pathway and mitochondrial involvement in the detrimental chain of events leading to neuronal degeneration.

Effect of electroconvulsive stimulation on morphological and physiological aspects of post-cardiac arrest cerebral microcirculation

We investigated the effect of electroconvulsive stimulation (ECS) on cerebral circulation in vivo using the method for measuring microcirculation in real time with the photosensitizer dye Photosense and the fiber optic spectrofluorometer LESA-01-BIOSPEC. We have found that electroconvulsive stimulation significantly improved cerebral microcirculation (fourfold higher comparing to the control cerebral perfusion) after 30 min of room-temperature cardiac arrest. Morphologic study of the brain tissue showed the absence of rouleaux formation of erythrocytes ("sludged blood") in the cerebral cortex microcirculation after the application of electrical stimulus. Electroconvulsive stimulation may be useful for improving cerebral microcirculation (blood flow) in cases of long-term brain hypoxia/anoxia after prolonged cardiac arrest.

Management of brain injury after resuscitation from cardiac arrest

The devastating neurologic injury in survivors of cardiac arrest has been recognized since the development of modern resuscitation techniques. After numerous failed clinical trials, two trials showed that induced mild hypothermia can ameliorate brain injury and improve survival and functional neurologic outcome in comatose survivors of out-of-hospital cardiac arrest. This article provides a comprehensive review of the advances in the care of brain injury after cardiac arrest, with updates on the process of prognostication, the use of therapeutic hypothermia and adjunctive intensive care unit care for cardiac arrest survivors.

Number needed to treat = six: therapeutic hypothermia following cardiac arrest--an effective and cheap approach to save lives

In 2005, the European Resuscitation Council (ERC) guidelines stated: Unconscious adult patients with spontaneous circulation after out-of-hospital ventricular fibrillation cardiac arrest should be cooled to 32 to 34°C for 12 to 24 hours. Patients with cardiac arrest from a non-shockable rhythm, in-hospital patients and children may also benefit from hypothermia. There is no argument to wait. We have to treat the next unconscious cardiac arrest patient with hypothermia.

Dying as a social relationship: a sociological review of debates on the determination of death

The research literature about 'brain death' is largely characterized by biomedical, bioethical and legal writing. This has led to overlooking wider but no less pertinent social, historical and cultural understandings about death. By ignoring the work of other social and clinical colleagues in the study of dying, the literature on the determination of death has become unnecessarily abstract and socially disconnected from parallel concerns about death and dying. This has led, and continues to lead to, incomplete suggestions and narrow discussions about the nature of death as well as an ongoing misunderstanding of general public and health care staff responses to brain death criteria. This paper provides a sociological outline of these problems through a review of the key literature on the determination of death.

The effect of 2-methoxyestradiol, a HIF-1 alpha inhibitor, in global cerebral ischemia in rats

Global cerebral ischemia is an important clinical problem with few effective treatments. The hippocampus, which is important for memory, is especially vulnerable during global ischemia. Brain-specific knockout of hypoxia inducible factor-1 alpha (HIF-1 alpha) has been shown to be protective in focal ischemia in vivo. 2-methoxyestradiol (2ME2) is a natural metabolite of estrogen that is known to inhibit HIF-1 alpha. We tested 2ME2 in a rat model of global cerebral ischemia. Global ischemia was induced with the two-vessel occlusion model (2VO) which entailed hemorrhagic hypotension to a mean arterial pressure of 38-42 mmHg with simultaneous bilateral common carotid artery occlusion for 8 minutes. Sprague-Dawley rats (male, 280-350 g) were randomly assigned to three groups: global ischemia (GI, n=17), global ischemia with 2ME2 treatment (GI + 2ME2, n=17) and sham surgery (sham, n=12). 2ME2 treatment (15 mg/kg in 1% DMSO) was rendered 10 minutes after reperfusion. Rats in the GI and sham groups received similar doses of the DMSO solvent. Rats were killed 24 hours, 72 hours and 7 days after reperfusion. Quantitative CA1 hippocampal cell counts demonstrated significantly lower cell survival in the GI + 2ME2 group compared to either the GI or sham groups, in spite of a statistically significant reduction in HIF-1 alpha by Western blotting analysis of the GI + 2ME2 group. We conclude that 2ME2 worsens outcomes after global ischemia in rats.

Intensive care for brain injury after cardiac arrest: therapeutic hypothermia and related neuroprotective strategies

Neurologic injury is the predominant cause of poor functional outcome in patients who are resuscitated from cardiac arrest. The management of these patients in the ICU can be challenging because of the paucity of effective therapies and lack of readily available diagnostic and prognostic tools. After several decades of failed pharmacologic neuroprotection trials, recent and well-designed randomized trials showed that therapeutic hypothermia is an effective neuroprotective measure in comatose survivors of cardiac arrest. Therapeutic hypothermia has been recommended by the International Liaison Committee on Resuscitation and has been incorporated in the American Heart Association CPR Guidelines. The American Academy of Neurology recently enhanced the delivery of care in survivors of cardiac arrest by providing evidence-based practice parameters on the prediction of poor outcome in comatose survivors of cardiac arrest, based on clinical evaluation and diagnostic tests. This article discusses these advances and their potential impact on the care provided in the ICU.

The effect of granulocyte-colony stimulating factor in global cerebral ischemia in rats

Granulocyte-colony stimulating factor (G-CSF) is an endogenous peptide hormone of the hematopoietic system that has entered Phase I/II clinical trials for treatment of ischemic stroke. Severe intraoperative hypotension can lead to global cerebral ischemia and apoptotic neuron loss within the hippocampus. We tested G-CSF in a rat model of global cerebral ischemia. Global cerebral ischemia was induced in male Sprague-Dawley rats (280-330 g) with the 2-vessel occlusion model (hemorrhagic hypotension to a mean arterial pressure of 30-35 mm Hg and bilateral common carotid artery occlusion for 8 min). Three groups of animals were used: global ischemia without treatment (GI, n=49), global ischemia with G-CSF treatment (GI+G-CSF, n=42), and sham surgery (Sham, n=26). Rats in the treatment group received G-CSF (50 mug/kg, subcutaneously) 12 h before surgery, on the day of surgery, and on postoperative Day 1 and were euthanized on Days 2, 3, and 14. Mild hyperglycemia was observed in all groups. T-maze testing for spontaneous alternation demonstrated initial improvement in the G-CSF treatment group but no long-term benefit. Measurement of daily body weight demonstrated an initial trend toward improvement in the G-CSF group. Quantitative Nissl histology of the hippocampus demonstrated equivalent outcomes on Days 3 and 14, which was supported by quantitative TUNEL stain. Immunohistochemistry and Western blot demonstrated an initial increase in phosphorylated-AKT in the GI+G-CSF group on Day 2. We conclude that G-CSF treatment is associated with transient early improvement in neurobehavioral outcomes after global ischemia complicated by mild hyperglycemia, but no long-term protection.