Airway inflammation induces anxiety-like behavior through neuroinflammatory, neurochemical, and neurometabolic changes in an allergic asthma model.

Allergic asthma is characterized by chronic airway inflammation and is constantly associated with anxiety disorder. Recent studies showed bidirectional interaction between the brain and the lung tissue. However, where and how the brain is affected in allergic asthma remains unclear. We aimed to investigate the neuroinflammatory, neurochemical, and neurometabolic alterations that lead to anxiety-like behavior in an experimental model of allergic asthma. Mice were submitted to an allergic asthma model induced by ovalbumin (OVA) and the control group received only Dulbecco's phosphate-buffered saline (DPBS). Our findings indicate that airway inflammation increases interleukin (IL) -9, IL-13, eotaxin, and IL-1ß release and changes acetylcholinesterase (AChE) and Na+,K+-ATPase activities in the brain of mice. Furthermore, we demonstrate that a higher reactive oxygen species (ROS) formation and antioxidant defense alteration that leads to protein damage and mitochondrial dysfunction. Therefore, airway inflammation promotes a pro-inflammatory environment with an increase of BDNF expression in the brain of allergic asthma mice. These pro-inflammatory environments lead to an increase in glucose uptake in the limbic regions and to anxiety-like behavior that was observed through the elevated plus maze (EPM) test and downregulation of glucocorticoid receptor (GR). In conclusion, the present study revealed for the first time that airway inflammation induces neuroinflammatory, neurochemical, and neurometabolic changes within the brain that leads to anxiety-like behavior. Knowledge about mechanisms that lead to anxiety phenotype in asthma is a beneficial tool that can be used for the complete management and treatment of the disease.

Pre- and early postnatal enriched environmental experiences prevent neonatal hypoxia-ischemia late neurodegeneration via metabolic and neuroplastic mechanisms.

Prenatal and early postnatal periods are important for brain development and neural function. Neonatal insults such as hypoxia-ischemia (HI) causes prolonged neural and metabolic dysregulation, affecting central nervous system maturation. There is evidence that brain hypometabolism could increase the risk of adult-onset neurodegenerative diseases. However, the impact of non-pharmacologic strategies to attenuate HI-induced brain glucose dysfunction is still underexplored. This study investigated the long-term effects of early environmental enrichment in metabolic, cell, and functional responses after neonatal HI. Thereby, male Wistar rats were divided according to surgical procedure, sham, and HI (performed at postnatal day 3), and the allocation to standard (SC) or enriched condition (EC) during gestation and lactation periods. In-vivo cerebral metabolism was assessed by means of [18 F]-FDG micro-positron emission tomography, and cognitive, biochemical, and histological analyses were performed in adulthood. Our findings reveal that HI causes a reduction in glucose metabolism and glucose transporter levels as well as hyposynchronicity in metabolic brain networks. However, EC during prenatal or early postnatal period attenuated these metabolic disturbances. A positive correlation was observed between [18 F]-FDG values and volume ratios in adulthood, indicating that preserved tissue by EC is metabolically active. EC promotes better cognitive scores, as well as down-regulation of amyloid precursor protein in the parietal cortex and hippocampus of HI animals. Furthermore, growth-associated protein 43 was up-regulated in the cortex of EC animals. Altogether, results presented support that EC during gestation and lactation period can reduce HI-induced impairments that may contribute to functional decline and progressive late neurodegeneration.

Long-term changes in metabolic brain network drive memory impairments in rats following neonatal hypoxia-ischemia.

BACKGROUND AND PURPOSE: Hypoxia and cerebral ischemia (HI) events are capable of triggering important changes in brain metabolism, including glucose metabolism abnormalities, which may be related to the severity of the insult. Using positron emission microtomography (microPET) with [18F]fluorodeoxyglucose (18F-FDG), this study proposes to assess abnormalities of brain glucose metabolism in adult rats previously submitted to the neonatal HI model. We hypothesize that cerebral metabolic outcomes will be associated with cognitive deficits and magnitude of brain injury. METHODS: Seven-day-old rats were subjected to an HI model, induced by permanent occlusion of the right common carotid artery and systemic hypoxia. 18F-FDG-microPET was used to assess regional and whole brain glucose metabolism in rats at 60 postnatal days (PND 60). An interregional cross-correlation matrix was utilized to construct metabolic brain networks (MBN). Rats were also subjected to the Morris Water Maze (MWM) to evaluate spatial memory and their brains were processed for volumetric evaluation. RESULTS: Brain glucose metabolism changes were observed in adult rats after neonatal HI insult, limited to the right brain hemisphere. However, not all HI animals exhibited significant cerebral hypometabolism. Hippocampal glucose metabolism was used to stratify HI animals into HI hypometabolic (HI-h) and HI non-hypometabolic (HI non-h) groups. The HI-h group had drastic MBN disturbance, cognitive deficit, and brain tissue loss, concomitantly. Conversely, HI non-h rats had normal brain glucose metabolism and brain tissue preserved, but also presented MBN changes and spatial memory impairment. Furthermore, data showed that brain glucose metabolism correlated with cognitive deficits and brain volume outcomes. CONCLUSIONS: Our findings demonstrated that long-term changes in MBN drive memory impairments in adult rats subjected to neonatal hypoxic ischemia, using in vivo imaging microPET-FDG. The MBN analyses identified glucose metabolism abnormalities in HI non-h animals, which were not detected by conventional 18F-FDG standardized uptake value (SUVr) measurements. These animals exhibited a metabolic brain signature that may explain the cognitive deficit even with no identifiable brain damage.

Depression comorbidity in epileptic rats is related to brain glucose hypometabolism and hypersynchronicity in the metabolic network architecture.

OBJECTIVE: Temporal lobe epilepsy (TLE) is one of the most common types of epilepsy syndromes in the world. Depression is an important comorbidity of epilepsy, which has been reported in patients with TLE and in different experimental models of epilepsy. However, there is no established consensus on which brain regions are associated with the manifestation of depression in epilepsy. Here, we investigated the alterations in cerebral glucose metabolism and the metabolic network in the pilocarpine-induced rat model of epilepsy and correlated it with depressive behavior during the chronic phase of epilepsy. METHODS: Fluorodeoxyglucose (18 F-FDG) was used to investigate the cerebral metabolism, and a cross-correlation matrix was used to examine the metabolic network in chronically epileptic rats using micro-positron emission tomography (microPET) imaging. An experimental model of epilepsy was induced by pilocarpine injection (320 mg/kg, ip). Forced swim test (FST), sucrose preference test (SPT), and eating-related depression test (ERDT) were used to evaluate depression-like behavior. RESULTS: Our results show an association between epilepsy and depression comorbidity based on changes in both cerebral glucose metabolism and the functional metabolic network. In addition, we have identified a significant correlation between brain glucose hypometabolism and depressive-like behavior in chronically epileptic rats. Furthermore, we found that the epileptic depressed group presents a hypersynchronous brain metabolic network in relation to the epileptic nondepressed group. SIGNIFICANCE: This study revealed relevant alterations in glucose metabolism and the metabolic network among the brain regions of interest for both epilepsy and depression pathologies. Thus it seems that depression in epileptic animals is associated with a more diffuse hypometabolism and altered metabolic network architecture and plays an important role in chronic epilepsy.

Antidepressant Effects of Ketamine Are Not Related to ¹8F-FDG Metabolism or Tyrosine Hydroxylase Immunoreactivity in the Ventral Tegmental Area of Wistar Rats.

Major depressive disorder (MDD) is an important health problem that is often associated to stress. One of the main brain regions related to MDD is the ventral tegmental area (VTA), a dopaminergic center, part of the reward and motivation circuitry. Recent studies show that changes to VTA dopaminergic neurons are associated with depression and treatment. Ketamine has recently shown a fast, potent antidepressant effect in acute, sub-anesthetic doses. Thus, our aims were to elucidate if ketamine would be able to revert depression-like behaviors induced by a chronic unpredictable stress (CUS) protocol and if it could cause alterations to metabolism and tyrosine hydroxylase (TH)-immunoreactivity in VTA. For this, 48 Wistar rats were divided into four groups: control + saline (CTRL + SAL), control + ketamine (CTRL + KET), CUS + saline (CUS + SAL), CUS + ketamine (CUS + KET). The CUS groups underwent 28 days of CUS protocol. Saline or ketamine (10 mg/kg) was administered intraperitonially once on day 28. The behavior was assessed by the sucrose preference test, the open field test, and the forced swim test. Glucose brain metabolism was assessed and quantified with microPET. TH-immunoreactivity was assessed by estimating neuronal density and regional and cellular optical densities. A decrease in sucrose intake in the CUS groups and an increase in immobility was rapidly reverted by ketamine (p < 0.05). No difference was observed in the open field test. There was no alteration to VTA metabolism and TH-immunoreaction. These results suggest that the depressive-like behavior induced by CUS and the antidepressant effects of ketamine are unrelated to changes in neuronal metabolism or dopamine production in VTA.

Comparison of two site-specifically (18)F-labeled affibodies for PET imaging of EGFR positive tumors.

The epidermal growth factor receptor (EGFR) serves as an attractive target for cancer molecular imaging and therapy. Our previous positron emission tomography (PET) studies showed that the EGFR-targeting affibody molecules (64)Cu-DOTA-ZEGFR:1907 and (18)F-FBEM-ZEGFR:1907 can discriminate between high and low EGFR-expression tumors and have the potential for patient selection for EGFR-targeted therapy. Compared with (64)Cu, (18)F may improve imaging of EGFR-expression and is more suitable for clinical application, but the labeling reaction of (18)F-FBEM-ZEGFR:1907 requires a long synthesis time. The aim of the present study is to develop a new generation of (18)F labeled affibody probes (Al(18)F-NOTA-ZEGFR:1907 and (18)F-CBT-ZEGFR:1907) and to determine whether they are suitable agents for imaging of EGFR expression. The first approach consisted of conjugating ZEGFR:1907 with NOTA and radiolabeling with Al(18)F to produce Al(18)F-NOTA-ZEGFR:1907. In a second approach the prosthetic group (18)F-labeled-2-cyanobenzothiazole ((18)F-CBT) was conjugated to Cys-ZEGFR:1907 to produce (18)F-CBT-ZEGFR:1907. Binding affinity and specificity of Al(18)F-NOTA-ZEGFR:1907 and (18)F-CBT-ZEGFR:1907 to EGFR were evaluated using A431 cells. Biodistribution and PET studies were conducted on mice bearing A431 xenografts after injection of Al(18)F-NOTA-ZEGFR:1907 or (18)F-CBT-ZEGFR:1907 with or without coinjection of unlabeled affibody proteins. The radiosyntheses of Al(18)F-NOTA-ZEGFR:1907 and (18)F-CBT-ZEGFR:1907 were completed successfully within 40 and 120 min with a decay-corrected yield of 15% and 41% using a 2-step, 1-pot reaction and 2-step, 2-pot reaction, respectively. Both probes bound to EGFR with low nanomolar affinity in A431 cells. Although (18)F-CBT-ZEGFR:1907 showed instability in vivo, biodistribution studies revealed rapid and high tumor accumulation and quick clearance from normal tissues except the bones. In contrast, Al(18)F-NOTA-ZEGFR:1907 demonstrated high in vitro and in vivo stability, high tumor uptake, and relative low uptake in most of the normal organs except the liver and kidneys at 3 h after injection. The specificity of both probes for A431 tumors was confirmed by their lower uptake on coinjection of unlabeled affibody. PET studies showed that Al(18)F-NOTA-ZEGFR:1907 and (18)F-CBT-ZEGFR:1907 could clearly identify EGFR positive tumors with good contrast. Two strategies for (18)F-labeling of affibody molecules were successfully developed as two model platforms using NOTA or CBT coupling to affibody molecules that contain an N-terminal cysteine. Al(18)F-NOTA-ZEGFR:1907 and (18)F-CBT-ZEGFR:1907 can be reliably obtained in a relatively short time. Biodistribution and PET studies demonstrated that Al(18)F-NOTA-ZEGFR:1907 is a promising PET probe for imaging EGFR expression in living mice.

Short-term consumption of highly processed diets varying in macronutrient content impair the sense of smell and brain metabolism in mice.

OBJECTIVE: Food processing greatly contributed to increased food safety, diversity, and accessibility. However, the prevalence of highly palatable and highly processed food in our modern diet has exacerbated obesity rates and contributed to a global health crisis. While accumulating evidence suggests that chronic consumption of such foods is detrimental to sensory and neural physiology, it is unclear whether its short-term intake has adverse effects. Here, we assessed how short-term consumption (<2 months) of three diets varying in composition and macronutrient content influence olfaction and brain metabolism in mice. METHODS: The diets tested included a grain-based standard chow diet (CHOW; 54% carbohydrate, 32% protein, 14% fat; #8604 Teklad Rodent diet , Envigo Inc.), a highly processed control diet (hpCTR; 70% carbohydrate, 20% protein, 10% fat; #D12450B, Research Diets Inc.), and a highly processed high-fat diet (hpHFD; 20% carbohydrate, 20% protein, 60% fat; #D12492, Research Diets Inc.). We performed behavioral and metabolic phenotyping, electro-olfactogram (EOG) recordings, brain glucose metabolism imaging, and mitochondrial respirometry in different brain regions. We also performed RNA-sequencing (RNA-seq) in the nose and across several brain regions, and conducted differential expression analysis, gene ontology, and network analysis. RESULTS: We show that short-term consumption of the two highly processed diets, but not the grain-based diet, regardless of macronutrient content, adversely affects odor-guided behaviors, physiological responses to odorants, transcriptional profiles in the olfactory mucosa and brain regions, and brain glucose metabolism and mitochondrial respiration. CONCLUSIONS: Even short periods of highly processed food consumption are sufficient to cause early olfactory and brain abnormalities, which has the potential to alter food choices and influence the risk of developing metabolic disease.

Antidepressant-Like Effects of Chronic Guanosine in the Olfactory Bulbectomy Mouse Model.

Major depressive disorder (MDD) leads to pervasive changes in the health of afflicted patients. Despite advances in the understanding of MDD and its treatment, profound innovation is needed to develop fast-onset antidepressants with higher effectiveness. When acutely administered, the endogenous nucleoside guanosine (GUO) shows fast-onset antidepressant-like effects in several mouse models, including the olfactory bulbectomy (OBX) rodent model. OBX is advocated to possess translational value and be suitable to assess the time course of depressive-like behavior in rodents. This study aimed at investigating the long-term behavioral and neurochemical effects of GUO in a mouse model of depression induced by bilateral bulbectomy (OBX). Mice were submitted to OBX and, after 14 days of recovery, received daily (ip) administration of 7.5 mg/kg GUO or 40 mg/kg imipramine (IMI) for 45 days. GUO and IMI reversed the OBX-induced hyperlocomotion and recognition memory impairment, hippocampal BDNF increase, and redox imbalance (ROS, NO, and GSH levels). GUO also mitigated the OBX-induced hippocampal neuroinflammation (IL-1, IL-6, TNF-α, INF-γ, and IL-10). Brain microPET imaging ([18F]FDG) shows that GUO also prevented the OBX-induced increase in hippocampal FDG metabolism. These results provide additional evidence for GUO antidepressant-like effects, associated with beneficial neurochemical outcomes relevant to counteract depression.

Neuroprotective effects of the CTK 01512-2 toxin against neurotoxicity induced by 3-nitropropionic acid in rats.

The mitochondrial inhibitor 3-nitropropionic acid (3-NP) induces excitotoxicity. The authors hypothesized that CTK 01512-2, a recombinant peptide calcium channel N-type blocker, and the TRPA1 antagonist, could show neuroprotective effects. The male Wistar rats received 3-NP [25 mg/kg (i.p.) for 7 days], and a treatment of CTK 01512-2 was delivered intrathecally (i.t.), thrice a week. The neuroprotective effects were evaluated by [18F]FDG MicroPET analysis. The CTK 01512-2 toxin was able to reestablish similar glucose uptakes on the control animals. To detect the neurobehavioral effects from 3-NP, three protocols (6.25, 12.5, 18.75 mg/kg of 3-NP (i.p.), for 3, 4, and 6 days, respectively) were evaluated by performance tests (open field test, walk footprint, elevated plus-maze, Y-maze, and the object recognition test). Important disabilities in the gait of the rats were seen, as well as memory deficits, and anxious behavior in the animals that were treated with all 3-NP protocols. The dose of 18.75 mg/kg (for 3 days) showed the most pronounced behavioral effects and lethality, while the rats treated with 12.5 mg/kg (for 4 days) showed behavioral effects similar to the 6.25 mg/kg dose (for 6 days). The third protocol was then repeated and the rats were treated with the CTK 01512-2 toxin to be evaluated behaviorally again. The recombinant peptide prevented all of the gait-evaluated parameters that were induced by 3-NP at a 6.25 mg/kg dose, which displayed an improvement in the exploratory activities. Overall, these results have reinforced the positive effects of CTK 01512-2 against the behavioral changes that were induced by the mitochondrial inhibitor 3-NP.

Neurotoxic and convulsant effects induced by jack bean ureases on the mammalian nervous system.

Ureases are microbial virulence factors either because of the enzymatic release of ammonia or due to many other non-enzymatic effects. Here we studied two neurotoxic urease isoforms, Canatoxin (CNTX) and Jack Bean Urease (JBU), produced by the plant Canavalia ensiformis, whose mechanisms of action remain elusive. The neurotoxins provoke convulsions in rodents (LD50 ∼2 mg/kg) and stimulate exocytosis in cell models, affecting intracellular calcium levels. Here, electrophysiological and brain imaging techniques were applied to elucidate their mode of action. While systemic administration of the toxins causes tonic-clonic seizures in rodents, JBU injected into rat hippocampus induced spike-wave discharges similar to absence-like seizures. JBU reduced the amplitude of compound action potential from mouse sciatic nerve in a tetrodotoxin-insensitive manner. Hippocampal slices from CNTX-injected animals or slices treated in vitro with JBU failed to induce long term potentiation upon tetanic stimulation. Rat cortical synaptosomes treated with JBU released L-glutamate. JBU increased the intracellular calcium levels and spontaneous firing rate in rat hippocampus neurons. MicroPET scans of CNTX-injected rats revealed increased [18]Fluoro-deoxyglucose uptake in epileptogenesis-related areas like hippocampus and thalamus. Curiously, CNTX did not affect voltage-gated sodium, calcium or potassium channels currents, neither did it interfere on cholinergic receptors, suggesting an indirect mode of action that could be related to the ureases' membrane-disturbing properties. Understanding the neurotoxic mode of action of C. ensiformis ureases could help to unveil the so far underappreciated relevance of these toxins in diseases caused by urease-producing microorganisms, in which the human central nervous system is affected.

Sex differences in the effects of acute stress on cerebral glucose metabolism: A microPET study.

Stress has been considered as a risk factor for the development and aggravation of several diseases. The hypothalamic-pituitary-adrenal axis (HPA) is one of the main actors for the stress response and homeostasis maintenance. Positron emission tomography (PET) has been used to evaluate neuronal activity and to study brain regions that may be related to the HPA axis response. Since neuroimaging is an important tool in detecting neuroendocrine-related changes, we used fluorodeoxyglucose-18 (18F-FDG) and positron emission microtomography (microPET) to evaluate sexual differences in the glucose brain metabolism after 10, 30 and 40 min of acute stress in Balb/c mice. We also investigated the effects of restraint stress in blood, liver and adrenal gland 18F-FDG biodistribution using a gamma counter. A decreased glucose uptake in the whole brain in both females and males was found. Additionally, there were time and sex-dependent alterations in the 18F-FDG uptake after restraint stress in specific brain regions, indicating that males could be more vulnerable to the short-term effects of acute stress. According to the gamma counter biodistribution, only females showed a significant decreased glucose uptake in the blood, liver and right adrenal after restraint stress. In addition, in comparisons between the sexes, males showed a decreased glucose uptake in the whole brain and in several brain regions compared to females. In conclusion, exposure to acute restraint stress resulted in significant decreased glucose metabolism in the brain, with particular effects in different regions and organs in a sex-specific manner.

Nociceptin/orphanin FQ receptor modulates painful and fatigue symptoms in a mouse model of fibromyalgia.

Generalized pain and fatigue are both hallmarks of fibromyalgia, a syndrome with an indefinite etiology. The treatment options for fibromyalgia are currently limited, probably because of its intricate pathophysiology. Thus, further basic and clinical research on this condition is currently needed. This study investigated the effects of nociceptin/orphanin FQ (N/OFQ) receptor (NOPr) ligands and the modulation of the NOP system in the preclinical mouse model of reserpine-induced fibromyalgia. The effects of administration of the natural agonist N/OFQ and the selective NOPr antagonists (UFP-101 and SB-612111) were evaluated in fibromyalgia-related symptoms in reserpine-treated mice. The expression of prepronociceptin/orphanin FQ and NOPr was assessed in central and peripheral sites at different time points after reserpine administration. Nociceptin/orphanin FQ displayed dual effects in the behavioral changes in the reserpine-elicited fibromyalgia model. The peptide NOPr antagonist UFP-101 produced analgesic and antifatigue effects, by preventing alterations in brain activity and skeletal muscle metabolism, secondary to fibromyalgia induction. The nonpeptide NOPr antagonist SB-612111 mirrored the favorable effects of UFP-101 in painful and fatigue alterations induced by reserpine. A time-related up- or downregulation of prepronociceptin/orphanin FQ and NOPr was observed in supraspinal, spinal, and peripheral sites of reserpine-treated mice. Our data shed new lights on the mechanisms underlying the fibromyalgia pathogenesis, supporting a role for N/OFQ-NOP receptor system in this syndrome.

Increases in dendritic spine density in BLA without metabolic changes in a rodent model of PTSD.

Imaging studies have shown abnormal amygdala function in patients with posttraumatic stress disorder (PTSD). In addition, alterations in synaptic plasticity have been associated with psychiatric disorders and previous reports have indicated alterations in the amygdala morphology, especially in basolateral (BLA) neurons, are associated with stress-related disorders. Since, some individuals exposed to a traumatic event develop PTSD, the goals of this study were to evaluate the early effects of PTSD on amygdala glucose metabolism and analyze the possible BLA dendritic spine plasticity in animals with different levels of behavioral response. We employed the inescapable footshock protocol as an experimental model of PTSD and the animals were classified according to the duration of their freezing behavior into distinct groups: "extreme behavioral response" (EBR) and "minimal behavioral response". We evaluated the amygdala glucose metabolism at baseline (before the stress protocol) and immediately after the situational reminder using the microPET and the radiopharmaceutical 18F-FDG. The BLA dendritic spines were analyzed according to their number, density, shape and morphometric parameters. Our results show the EBR animals exhibited longer freezing behavior and increased proximal dendritic spines density in the BLA neurons. Neither the amygdaloid glucose metabolism, the types of dendritic spines nor their morphometric parameters showed statistically significant differences. The extreme behavior response induced by this PTSD protocol produces an early increase in BLA spine density, which is unassociated with either additional changes in the shape of spines or metabolic changes in the whole amygdala of Wistar rats.

Ketamine promotes increased freezing behavior in rats with experimental PTSD without changing brain glucose metabolism or BDNF.

Acute treatment with ketamine, an NMDA receptor antagonist, has been reported to be efficacious in treating depression. The goal of our study was to evaluate ketamine treatment in an animal model of another important psychiatric disease, post-traumatic stress disorder (PTSD). Fifty-eight male rats were initially divided into four groups: Control+Saline (CTRL+SAL), Control+Ketamine (CTRL+KET), PTSD+Saline (PTSD+SAL) and PTSD+Ketamine (PTSD+KET). To mimic PTSD we employed the inescapable footshock protocol. The PTSD animals were classified according to freezing behavior duration into "extreme behavioral response" (EBR) or "minimal behavioral response" (MBR). Afterwards, the glucose metabolism and BDNF were evaluated in the hippocampus, frontal cortex, and amygdala. Our results show that animals classified as EBR exhibited increased freezing behavior and that ketamine treatment further increased freezing duration. Glucose metabolism and BDNF levels showed no significant differences. These results suggest ketamine might aggravate PTSD symptoms and that this effect is unrelated to alterations in glucose metabolism or BDNF protein levels.

Small Peptide and Protein-based Molecular Probes for Imaging Neurological Diseases.

Neurologic disorders are prevalent diseases in the population and represent a major cause of death and disability. Despite the advances made during recent decades, the early diagnosis of these diseases remains a challenge. Determining the pathophysiology of such disorders is also challenging and is a requirement for the development of new drugs and treatments. Molecular neuroimaging studies can help fill these gaps in knowledge by providing clinicians with the tools necessary to diagnose and monitor treatment response and by providing data to help researchers understand the mechanisms of disease. Molecular imaging is a fast-growing field of research, and the development of imaging probes is crucial to molecular imaging research. Imaging based on peptide and small protein molecular probes provides many advantages over traditional neuroimaging for the identification of many pathological aspects of nervous diseases, especially gliomas, for which this type of imaging is gradually being moved to clinical settings. Nonetheless, peptide and small protein imaging also has potential applications in other neurologic diseases such as stroke, Parkinson's disease and Alzheimer's disease. This review is focused on the main peptide and small protein probes used for molecular imaging in neurologic disease.

Transplantation of bone marrow mononuclear cells prolongs survival, delays disease onset and progression and mitigates neuronal loss in pre-symptomatic, but not symptomatic ALS mice.

Cell-based therapy provides a novel strategy to restore lost neurons or modulate the degenerating microenvironment in amyotrophic lateral sclerosis (ALS). This study verified the therapeutic potential of bone marrow mononuclear cells (BMMCs) in SOD1G93A mice. BMMCs were obtained from enhanced green fluorescent protein (EGFP) transgenic C57BL/6 mice (EGFPBMMCs) or from SOD1G93A transgenic mice (mSOD1BMMCs) and given to mice at the pre-symptomatic or late symptomatic stage. Survival, body weight and motor performance data were recorded. DNA integrity was evaluated using the alkaline comet assay. The spinal cords were collected to assess motoneuron preservation and cell migration. EGFPBMMCs and mSOD1BMMCs transplantation to pre-symptomatic SOD1G93A mice prolonged survival and delayed disease progression. The effects were more significant for the EGFPBMMC-transplanted mice. In late symptomatic mice, EGFPBMMCs promoted a discrete increase in survival, without other clinical improvements. DNA from EGFPBMMCs and mSOD1BMMCs was found in the spinal cords of transplanted animals. DNA damage was not modified by BMMCs in any of the studied groups. Despite positive behavioral effects observed in our study, the limited results we observed for late transplanted mice call for caution before clinical application of BMMCs in ALS.

The antiepileptic activity of JSTX-3 is mediated by N-methyl-D-aspartate receptors in human hippocampal neurons.

We analyzed the effect of the acylpolyaminetoxin JSTX-3 on the epileptogenic discharges induced by perfusion of human hippocampal slices with artificial cerebrospinal fluid lacking Mg2+ or N-methyl-D-aspartate. Hippocampi were surgically removed from patients with refractory medial temporal lobe epilepsy, sliced in the surgical room and taken to the laboratory immersed in normal artificial cerebrospinal fluid. Epileptiform activity was induced by perfusion with Mg2+-free artificial cerebrospinal fluid or by iontophoretically applied N-methyl-D-aspartate and intracellular and field recordings of CA1 neurons were performed. The ictal-like discharges induced by Mg2+-free artificial cerebrospinal fluid and N-methyl-D-aspartate were blocked by incubation with JSTX-3. This effect was similar to that obtained with the N-methyl-D-aspartate receptor antagonist DL (-)2-amino-5 phosphonovaleric acid. Our findings suggest that in human hippocampal neurons, the antiepileptic effect of JSTX-3 is mediated by its action on N-methyl-D-aspartate receptor.

Antiepileptic effect of acylpolyaminetoxin JSTX-3 on rat hippocampal CA1 neurons in vitro.

The Joro spider toxin (JSTX-3), derived from Nephila clavata, has been found to block glutamate excitatory activity. Epilepsy has been studied in vitro, mostly on rat hippocampus, through brain slices techniques. The aim of this study is to verify the effect of the JSTX-3 on the epileptiform activity induced by magnesium-free medium in rat CA1 hippocampal neurons. Experiments were performed on hippocampus slices of control and pilocarpine-treated Wistar rats, prepared and maintained in vitro. Epileptiform activity was induced through omission of magnesium from the artificial cerebrospinal fluid (0-Mg2+ ACSF) superfusate and iontophoretic application of N-methyl-D-aspartate (NMDA). Intracellular recordings were obtained from CA1 pyramidal neurons both of control and epileptic rats. Passive membrane properties were analyzed before and after perfusion with the 0-Mg2+ ACSF and the application of toxin JSTX-3. During the ictal-like activity, the toxin JSTX-3 was applied by pressure ejection, abolishing this activity. This effect was completely reversed during the washout period when the slices were formerly perfused with artificial cerebrospinal fluid (ACSF) and again with 0-Mg2+ ACSF. Our results suggest that the toxin JSTX-3 is a potent blocker of induced epileptiform activity.

Transplantation of bone marrow mononuclear cells modulates hippocampal expression of growth factors in chronically epileptic animals.

AIMS: In previous studies, transplantation of bone marrow mononuclear cells (BMMCs) in epileptic animals has been found to be neuroprotective. However, the mechanism by which the BMMCs act remains unclear. We hypothesize that BMMCs may provide neuroprotection to the epileptic brain through trophic support. To test our hypothesis, we studied the temporal expression of neurotrophins after BMMC transplantation in the epileptic rat hippocampus. METHODS: Chronically epileptic rats were intravenously transplanted with 1 × 10(7) BMMCs isolated from GFP transgenic mice. Expression levels of BDNF, GDNF, NGF, VEGF, and TGF-ß1, and their receptors, were evaluated by ELISA and/or qRT-PCR analysis. RESULTS: Our data revealed increased protein expression of BDNF, GDNF, NGF, and VEGF and reduced levels of TGF-ß1 in the hippocampus of transplanted epileptic animals. Additionally, an increase in the mRNA expression of BDNF, GDNF, and VEGF, a reduction in TGF-ß1, and a decrease in mRNA levels of the TrkA and TGFR-ß1 receptors were also observed. CONCLUSION: The gain provided by transplanted BMMCs in the epileptic brain may be related to the ability of these cells in modulating the network of neurotrophins and angiogenic signals.

Intra-arterial transplantation of human umbilical cord blood mononuclear cells in neonatal hypoxic-ischemic rats.

UNLABELLED: Based on preclinical findings, cellular therapy has become a promising therapeutic approach for neonatal hypoxia-ischemia (HI). However, before translation into the clinical setting, new and effective routes of cell delivery must be determined. Intra-arterial (IA) delivery is an attractive route of cellular administration but has never been used in neonatal HI rats. AIMS: In this study, we investigated the feasibility of IA transplantation of human umbilical cord blood (HUCB) mononuclear cells for the treatment of long-term behavior dysfunction and brain lesion after neonatal HI. MAIN METHODS: Seven-day-old rats were subjected to a HI model and the animals received HUCB mononuclear cells into the left common carotid artery 24 h after HI insult. KEY FINDINGS: At 9 weeks post-HI, intra-arterially transplanted HUCB mononuclear cells significantly improved learning and long-term spatial memory impairments when evaluated by the Morris water maze paradigm. There was no effect of neonatal HI insult or IA procedure on body weight and on motor coordination and balance when evaluated by the accelerating rotarod test. Cellular transplantation by the IA route did not restore neonatal HI-induced brain damage according to stereological volume assessment. Furthermore, HUCB mononuclear cells were tracked in the injured brain and peripheral organs of HI transplanted-rats by nested polymerase chain reaction analysis at different time points. SIGNIFICANCE: Our findings contribute to the translational knowledge of cell based-therapy in neonatal HI and demonstrate for the first time that IA transplantation into rat pups is a feasible route for cellular delivery and prevents long-term cognitive deficits induced by experimental neonatal HI.