Blood glutamate scavenging as a novel glutamate-based therapeutic approach for post-stroke depression.

Post-stroke depression (PSD) is a major complication of stroke that significantly impacts functional recovery and quality of life. While the exact mechanism of PSD is unknown, recent attention has focused on the association of the glutamatergic system in its etiology and treatment. Minimizing secondary brain damage and neuropsychiatric consequences associated with excess glutamate concentrations is a vital part of stroke management. The blood glutamate scavengers, oxaloacetate and pyruvate, degrade glutamate in the blood to its inactive metabolite, 2-ketoglutarate, by the coenzymes glutamate-oxaloacetate transaminase (GOT) and glutamate-pyruvate transaminase (GPT), respectively. This reduction in blood glutamate concentrations leads to a subsequent shift of glutamate down its concentration gradient from the blood to the brain, thereby decreasing brain glutamate levels. Although there are not yet any human trials that support blood glutamate scavengers for clinical use, there is increasing evidence from animal research of their efficacy as a promising new therapeutic approach for PSD. In this review, we present recent evidence in the literature of the potential therapeutic benefits of blood glutamate scavengers for reducing PSD and other related neuropsychiatric conditions. The evidence reviewed here should be useful in guiding future clinical trials.

The effect of depressive-like behavior and antidepressant therapy on social behavior and hierarchy in rats.

BACKGROUND: Depression is common and results in a significant morbidity and economic burden. Depression is associated with pervasive impairments in social functioning, and antidepressant treatments are highly variable in improving these impairments. The objectives of this study were to test the effects of depression on social organization and behavior in a rodent model of depression, and to study the effectiveness of antidepressant medication in improving both symptoms of depression and the social function of depressed animals. METHODS: One hundred-twenty male Sprague-Dawley rats were randomly and equally divided between the control group and depression group. After induction of depression by 5 weeks of chronic unpredictable stress, rats received either antidepressant treatment or placebo. In parallel with the initiation of drug therapy, 20 social groups of six rats were subjected to the complex diving-for-food situation to evaluate their social functioning. Four behavioral tests evaluated symptoms of depression and anxiety at 3 different time points. RESULTS: We found that 1) depressed rats were significantly more active and aggressive in all parameters of social organization test compared with the control and antidepressant treatment groups, 2) depressed rats that received antidepressant treatment exhibited social behaviors like the control group, and 3) depression in the experimental groups was not accompanied by symptoms of anxiety. CONCLUSIONS: These results suggest that depression can significantly alter the social behavior and hierarchy in the social group in rats. Investigations of complex social group dynamics offer novel opportunities for translational studies of mood and psychiatric disorders.

Establishment of novel technical methods for evaluating brain edema and lesion volume in stroked rats: A standardization of measurement procedures.

Stroke plays a role in high morbidity and mortality. Deciphering its mechanisms and pathophysiology is critical for the creation of new drugs and therapies. Most of the previous animal models of stroke, aimed at identifying the extent and location of brain injury following stroke, require animal sacrifice, which, besides ethical considerations, also negates the ability for follow up studies with the same rats. Because of these failures, the use of clinical magnetic resonance scanners for evaluating small animal models has been increasing. Magnetic resonance imaging scanners used particularly for small-bore animals are eligible for use in high-resolution magnetic resonance imaging of rodent brains. However, high costs and scarcity factor heavily in the rare availability of these scanners. In our investigation, we sought to establish a unitary magnetic resonance imaging protocol for stroke assessment in rats. We made use of a 3-Tesla magnetic resonance imaging clinical scanner, as well as another clinical equipment, with the purpose of increasing its reproducibility. The results of inquest validated a new magnetic resonance imaging protocol, comparing a magnetic resonance imaging-measured infarcted zone to the "gold standard" of histological examination. We carried out the experimental procedure on a 3 Tesla magnetic resonance imaging clinical scanner using a conventional eight-channel receive-only coil. The two methods produced remarkable quantitative and qualitative correlations between them. Conclusively, we showed the clinical magnetic resonance imaging scanner to be a high-precision and sensitive image analysis instrument for evaluating both the infarct zone and the brain edema in a stroke experimental rat model.

Blood Glutamate Reducing Effect of Hemofiltration in Critically Ill Patients.

Glutamate toxicity plays a well-established role in secondary brain damage following acute and chronic brain insults. Previous studies have demonstrated the efficacy of hemodialysis and peritoneal dialysis in reducing blood glutamate levels. However, these methods are not viable options for hemodynamically unstable patients. Given more favorable hemodynamics, longer treatment, and less needed anticoagulation, we investigated whether hemofiltration could be effective in lowering blood glutamate levels. Blood samples were taken from 10 critically ill patients immediately before initiation of hemofiltration and after 1, 2, 4, 6, and 12 h, for a total of 6 blood samples. Samples were sent for determination of glutamate, glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), hemoglobin, hematocrit, urea, creatinine, glucose, sodium, potassium, platelet, and white blood cell (WBC) levels. There was a statistically significant reduction in blood glutamate levels at all time points compared to baseline levels. There was no difference in levels of GOT or GPT. Hemofiltration can be a promising method of reducing blood glutamate levels, especially in critically ill patients where hemodialysis and peritoneal dialysis may be contraindicated.

Clinical outcome of critically ill patients with thrombocytopenia and hypophosphatemia in the early stage of sepsis.

BACKGROUND: Hypophosphatemia and thrombocytopenia may both be independent risk factors for the development of multiple organ failure and correlate well with the severity of sepsis. In the present study we wanted to analyze the potential clinical role and prognostic significance of both early hypophosphatemia and thrombocytopenia on clinical outcomes of critically ill ICU patients with severe sepsis. METHODS: We analyzed the clinical data, including the outcome of critically ill ICU patients with severe sepsis who presented during a 5 year period with early hypophosphatemia and thrombocytopenia.This study was retrospective and single centre. All clinical and laboratory data was collected from the patients' ICU and hospital electronic records. All laboratory measurements were done on admission and during the ICU stay. RESULTS: The included patients were distributed into one of three study groups based on the presence of hypophosphatemia and/or thrombocytopenia during the first 24 hours of admission to the ICU: group 1 - early hypophosphatemia; group 2 - early hypophosphatemia and thrombocytopenia and group 3 - early thrombocytopenia. The ICU mortality rate was significantly higher in groups 2 and 3 (25.9% and 22% vs. 9.3%, respectively, P = 0.034). An APACHE II > 27, a TISS > 25 following the first 24 hours of ICU stay , an age higher than 70, male gender and total parenteral nutrition were independent predictors of ICU and hospital mortality in this study population. CONCLUSION: It may be considered that hypophosphatemia and thrombocytopenia in the early stage of sepsis, even when severe and coexisting, reflect the degree of initial illness severity of sepsis. However, further investigations need to be done for a better understanding of the potential clinical role of these features in the septic critically ill population.

Positive fluid balance as a major predictor of clinical outcome of patients with sepsis/septic shock after ICU discharge.

INTRODUCTION: Sepsis and septic shock continue to be syndromes that carry a high mortality rate worldwide. Early aggressive fluid and vasopressor support have resulted in significant improvement in patient outcomes. The prognostic clinical significance of a positive fluid balance in septic intensive care unit (ICU) patients remains undetermined. METHODS: We collected data from 297 septic patients hospitalized in our general and medical ICUs at Soroka Medical Center between January 2005 and June 2011 and divided the 4 study groups into the following 4 fluid balances: group 1, patients with fluid balance at discharge from ICU (FBD) less than 10 L; group 2, patients with an FBD of 10 to 20 L; group 3, patients with an FBD of 20 to 30 L; and group 4, patients with FBD in excess of 30 L. RESULTS: The ICU and in-hospital mortality rate was also significantly higher in groups 2 to 4 as compared with group 1 (P < .001 for both ICU and in-hospital mortality). The positive cumulative FBD was found to be an independent predictor of ICU mortality (odds ratio [OR], 1.04; 95% confidence interval [CI], 1.02-1.06; P < .001; Table 3) and in-hospital mortality (OR, 1.06; 95% CI, 1.03-1.08; P < .001; Table 5) and also to constitute a risk factor for new organ system dysfunction at hospital discharge (OR, 1.01; 95% CI, 1.01-1.013; P < .001; Table 6) in critically ill patients with severe sepsis/septic shock. CONCLUSIONS: Although it is a monocentric retrospective study, we suggest that positive cumulative fluid balance is one of the major factors that can predict the clinical outcome of critically ill patients during their ICU stay and after their discharge from the ICU.

Neuroprotection by Estrogen and Progesterone in Traumatic Brain Injury and Spinal Cord Injury.

In recent years there has been a growing body of clinical and laboratory evidence demonstrating the neuroprotective effects of estrogen and progesterone after traumatic brain injury (TBI) and spinal cord injury (SCI). In humans, women have been shown to have a lower incidence of morbidity and mortality after TBI compared with age-matched men. Similarly, numerous laboratory studies have demonstrated that estrogen and progesterone administration is associated with a mortality reduction, improvement in neurological outcomes, and a reduction in neuronal apoptosis after TBI and SCI. Here, we review the evidence that supports hormone-related neuroprotection and discuss possible underlying mechanisms. Estrogen and progesterone-mediated neuroprotection are thought to be related to their effects on hormone receptors, signaling systems, direct antioxidant effects, effects on astrocytes and microglia, modulation of the inflammatory response, effects on cerebral blood flow and metabolism, and effects on mediating glutamate excitotoxicity. Future laboratory research is needed to better determine the mechanisms underlying the hormones' neuroprotective effects, which will allow for more clinical studies. Furthermore, large randomized clinical control trials are needed to better assess their role in human neurodegenerative conditions.

Anesthetic Management of Patients with Congenital Insensitivity to Pain with Anhidrosis: A Retrospective Analysis of 358 Procedures Performed Under General Anesthesia.

BACKGROUND: Congenital insensitivity to pain with anhidrosis (CIPA) is a rare autosomal recessive disorder characterized by recurrent episodic fevers, anhidrosis, absent reaction to noxious stimuli, self-mutilating behavior, and mental retardation. The anesthetic management of patients with CIPA is challenging. Autonomic nervous system abnormalities are common, and patients are at increased risk for perioperative complications. METHODS: In this study, we describe our experience with 35 patients with CIPA who underwent 358 procedures requiring general anesthesia between 1990 and 2013. RESULTS: During surgery, 3 patients developed hyperthermia intraoperatively (>37.5°C) without prior fever. There were no cases of intraoperative hyperpyrexia (>40°C). Aspiration was suspected in 2 patients, and in another patient aspiration was prevented by the use of endotracheal tube, early detection of regurgitation, and aggressive suctioning. One patient had cardiac arrest requiring cardiopulmonary resuscitation. Intraoperative bradycardia was observed in 10 cases, and postoperative bradycardia was observed in 11 cases. CONCLUSIONS: Regurgitation, hyperthermia, and aspiration were uncommon, but the incidence of bradycardia was higher than has been reported in previous studies. CIPA remains a challenge for anesthesiologists. Because of the rare nature of this disorder, the risk of various complications is difficult to predict.

Epidemiology of new-onset paroxysmal atrial fibrillation in the General Intensive Care Unit population and after discharge from ICU. A retrospective epidemiological study.

BACKGROUND: Evidence of various cardiac arrhythmias in septic patients has been demonstrated by multiple clinical reports and observations. Most cardiac arrhythmias in sepsis are new-onset and may be related to sepsis-induced myocardial dysfunction. We propose to investigate and analyze data of new-onset paroxysmal atrial fibrillation (AF) in a critically ill septic population. METHODS: This is a retrospective epidemiologic study. We collected clinical data from two hundred septic patients who developed a new episode of atrial fibrillation during their hospitalization in General Intensive Care Unit (GICU) between January 2007 and June 2013. RESULTS: Of these 200 septic patients, 81 septic patients developed a new episode of AF and included in the present study. Thirty-seven patients had no past medical history of atrial fibrillation (AF) or antiarrhythmic therapy (new episode of atrial fibrillation, Group 1) and 44 had previously known episodes of atrial fibrillation and were prescribed antiarrhythmic therapy at home (Group 2). Group 2 patients had longer duration of recurrent episodes of atrial fibrillation compared to patients in Group 1 (11.07 ± 8.7 vs. 7.4 ± 6.1 days; P = 0.013). The overall ICU and in-hospital mortality rate was similar in both study groups. There was no significant difference in new stroke and pulmonary embolism (PE) between both study groups (P > 0.05). CONCLUSION: In the present study we demonstrated no difference in morbidity and mortality rate in-ICU and after discharge between septic patients who had previous AF episodes and patients who had no previous past medical history of any cardiac arrhythmias.

Establishment of an animal model of depression contagion.

BACKGROUND: Depression is a common and important cause of morbidity, and results in a significant economic burden. Recent human studies have demonstrated that that depression is contagious, and depression in family and friends might cumulatively increase the likelihood that a person will exhibit depressive behaviors. The mechanisms underlying contagion depression are poorly understood, and there are currently no animal models for this condition. METHODS: Rats were divided into 3 groups: depression group, contagion group, and control group. After induction of depression by 5 weeks of chronic unpredictable stress, rats from the contagion group were housed with the depressed rats (1 naïve rat with 2 depressed rats) for 5 weeks. Rats were then subjected to sucrose preference, open field, and forced swim tests. RESULTS: The sucrose preference was significantly reduced in the depressed rats (p<0.01) and contagion depression rats (p<0.01). Climbing time during forced swim test was reduced in the depression and contagion depression groups (p<0.001), whereas immobility time was significantly prolonged in only the depression group (p<0.001). Rats in both the depression (p<0.05) and depression contagion group (p<0.005) had decreased total travel distance and decreased mean velocity in the open field test, whereas the time spent in the central part was significantly shorter in only the depression group (p<0.001). CONCLUSIONS: In this study, for the first time we demonstrated depression contagion in an animal model. A reliable animal model may help better understand the underlying mechanisms of contagion depression, and may allow for future investigations of the studying therapeutic modalities.

Use of early inhaled nitric oxide therapy in fat embolism syndrome to prevent right heart failure.

Fat embolism syndrome (FES) is a life-threatening condition in which multiorgan dysfunction manifests 48-72 hours after long bone or pelvis fractures. Right ventricular (RV) failure, especially in the setting of pulmonary hypertension, is a frequent feature of FES. We report our experience treating 2 young, previously healthy trauma patients who developed severe hypoxemia in the setting of FES. Neither patient had evidence of RV dysfunction on echocardiogram. The patients were treated with inhaled nitric oxide (NO), and their oxygenation significantly improved over the subsequent few days. Neither patient developed any cardiovascular compromise. Patients with FES that have severe hypoxemia and evidence of adult respiratory distress syndrome (ARDS) are likely at risk for developing RV failure. We recommend that these patients with FES and severe refractory hypoxemia should be treated with inhaled NO therapy prior to the onset of RV dysfunction.

Association between Hypophosphatemia and Cardiac Arrhythmias in the Early Stage of Sepsis: Could Phosphorus Replacement Treatment Reduce the Incidence of Arrhythmias?

It is well known that new-onset arrhythmias are common in septic patients. It is thought that hypophosphatemia in the early stages of sepsis may contribute to the development of new arrhythmias. In this study, we hypothesized that intravenous (IV) phosphorus replacement may reduce the incidence of arrhythmias in critically ill patients. 34 adult septic patients with hypophosphatemia admitted to the general intensive care unit were treated with IV phosphorus replacement per ICU protocol, and the incidence of new arrhythmias were compared with 16 patients from previously published data. IV phosphorus replacement was associated with a significantly reduced incidence of arrhythmias (38% vs. 63%, p=0.04). There were no differences in observed mortality between subgroups, which may be due to the small sample size. This study demonstrated that IV phosphorus replacement might be effective in reducing the incidence of new arrhythmias in septic patients.

The influence of aging on poststroke depression using a rat model via middle cerebral artery occlusion.

Poststroke depression (PSD) is the most frequent psychological sequela following stroke. While previous studies describe the impact of age on brain infarct volume, brain edema, and blood-brain barrier (BBB) breakdown following ischemia, the role of age on PSD has yet to be described. Here, we examine the influence of age on PSD progression in a rat model of PSD by middle cerebral artery occlusion (MCAO). One hundred forty-three rats were divided into three groups. 48 rats 20 weeks of age underwent a sham procedure, 51 rats 20 weeks of age had MCAO, and 44 rats 22-26 months of age had MCAO. Groups were further divided into two subgroups. The first subgroup was used to measure infarct lesion volume, brain edema, and BBB breakdown at 24 h. In the second subgroup at 3 weeks after MCAO, rats were subjected to a sucrose preference test, two-way shuttle avoidance task, forced swimming test, and a brain-derived neurotrophic factor (BDNF) protein level measurement. Total and striatal infarct volume, brain edema, and BBB breakdown in the striatum were increased in older rats, as compared with younger rats. While both old and young rats exhibited depressive-like behaviors on each of the behavioral tests and lower BDNF levels post-MCAO, as compared with control rats, there were no differences between old and young rats. Although older rats suffered from larger infarct volumes, increased brain edema and more BBB disruption following MCAO, the lack of behavioral differences between young and old rats suggests that there was no effect of rat age on the incidence of PSD.