Mast Cell Activation Profile and TFH13 Detection Discriminate Food Anaphylaxis Versus Sensitization

BACKGROUND AND OBJECTIVE

The prevalence of food allergy (FA) has increased significantly, and the risk of developing anaphylaxis is unpredictable. Thus, discriminating between sensitized patients and those at risk of having a severe reaction is of utmost interest. To explore mast cell activation pattern and T follicular helper (TFH) 13 presence in sensitized and food anaphylaxis patients.

METHODS

Patients sensitized to Lipid transfer protein (LTP) were classified as anaphylaxis or sensitized depending on the symptoms elicited by LTP-containing food. CD34+-derived MCs from patients and controls were obtained, sensitized with pooled sera, and challenged with Pru p 3 (peach LTP). Degranulation, PGD2, and cytokine/chemokine release were measured. The TFH13 population was examined by flow cytometry in the peripheral blood of all groups. In parallel, LAD2 cells were activated similarly to patients' MCs.

RESULTS

A distinguishable pattern of mast cell activation was found in anaphylaxis compared to sensitized patients. Robust degranulation, PGD2, and IL-8 and GM-CSF secretion were higher in anaphylaxis, whereas TFG- and CCL2 secretion increased in sensitized patients. Concomitantly, anaphylaxis patients had a larger TFH13 population. MC activation profile was dependent on the sera rather than the MC source. In agreement with that, LAD2 cells reproduce the same pattern as MCs from anaphylactic and sensitized patients.

CONCLUSION

The distinct profile of mast cell activation allows to discriminate between anaphylaxis and sensitized patients. Pooled sera may determine mast cell activation independently of mast cell origin. Besides, the presence of TFH13 cells in anaphylaxis patients points to an essential role of IgE affinity.

A Single High Dose of Flufenamic Acid in Rats does not Reduce the Damage Associated with the Rat Lithium-Pilocarpine Model of Status Epilepticus but Leads to Deleterious Outcomes

BACKGROUND

Epilepsy is one of the most common neurologic diseases, and around 30% of all epilepsies, particularly the temporal lobe epilepsy (TLE), are highly refractory to current pharmacological treatments. Abnormal synchronic neuronal activity, brain glucose metabolism alterations, neurodegeneration and neuroinflammation are features of epilepsy. Further, neuroinflammation has been shown to contribute to dysregulation of neuronal excitability and the progression of epileptogenesis. Flufenamic acid (FLU), a non-steroidal anti-inflammatory drug, is also characterized by its wide properties as a dose-dependent ion channel modulator. In this context, in vitro studies have shown that it abolishes seizure-like events in neocortical slices stimulated with a gamma-aminobutyric acid A (GABAA) receptor blocker. However, little is known about its effects in animal models. Thus, our goal was to assess the efficacy and safety of a relatively high dose of FLU in the lithium-pilocarpine rat model of status epilepticus (SE). This animal model reproduces many behavioral and neurobiological features of TLE such as short-term brain hypometabolism, severe hippocampal neurodegeneration and inflammation reflected by a marked reactive astrogliosis.

METHODS

FLU (100 mg/kg, i.p.) was administered to adult male rats, 150 min before SE induced by pilocarpine. Three days after the SE, brain glucose metabolism was assessed by 2-deoxy-2-[18F]-fluoro-D-glucose ([18F]FDG) positron emission tomography (PET). Markers of hippocampal integrity, neurodegeneration and reactive astrogliosis were also evaluated.

RESULTS

FLU neither prevented the occurrence of the SE nor affected brain glucose hypometabolism as assessed by [18F]FDG PET. Regarding the neurohistochemical studies, FLU neither prevented neuronal damage nor hippocampal reactive astrogliosis. On the contrary, FLU increased the mortality rate and negatively affected body weight in the rats that survived the SE.

CONCLUSIONS

Our results do not support an acute anticonvulsant effect of a single dose of FLU. Besides, FLU did not show short-term neuroprotective or anti-inflammatory effects in the rat lithium-pilocarpine model of SE. Moreover, at the dose administered, FLU resulted in deleterious effects.

PET Imaging and Neurohistochemistry Reveal that Curcumin Attenuates Brain Hypometabolism and Hippocampal Damage Induced by Status Epilepticus in Rats

Numerous preclinical studies provide evidence that curcumin, a polyphenolic phytochemical extracted from Curcuma longa (turmeric) has neuroprotective, anti-inflammatory and antioxidant properties against various neurological disorders. Curcumin neuroprotective effects have been reported in different animal models of epilepsy, but its potential effect attenuating brain glucose hypometabolism, considered as an early marker of epileptogenesis that occurs during the silent period following status epilepticus (SE), still has not been addressed. To this end, we used the lithium-pilocarpine rat model to induce SE. Curcumin was administered orally (300 mg/kg/day, for 17 days). Brain glucose metabolism was evaluated in vivo by 2-deoxy-2-[¹⁸F]Fluoro-D-Glucose ([¹⁸F]FDG) positron emission tomography (PET). In addition, hippocampal integrity, neurodegeneration, microglia-mediated neuroinflammation, and reactive astrogliosis were evaluated as markers of brain damage. SE resulted in brain glucose hypometabolism accompanied by body weight (BW) loss, hippocampal neuronal damage, and neuroinflammation. Curcumin did not reduce the latency time to the SE onset, nor the mortality rate associated with SE. Nevertheless, it reduced the number of seizures, and in the surviving rats, curcumin protected BW and attenuated the short-term glucose brain hypometabolism as well as the signs of neuronal damage and neuroinflammation induced by the SE. Overall, our results support the potential adaptogen-like effects of curcumin attenuating key features of SE-induced brain damage.

The vasodilator naftidrofuryl attenuates short-term brain glucose hypometabolism in the lithium-pilocarpine rat model of status epilepticus without providing neuroprotection

Status epilepticus (SE) triggered by lithium-pilocarpine is a model of epileptogenesis widely used in rats, reproducing many of the pathological features of human temporal lobe epilepsy (TLE). After the SE, a silent period takes place that precedes the occurrence of recurrent spontaneous seizures. This latent stage is characterized by brain glucose hypometabolism and intense neuronal damage, especially at the hippocampus. Importantly, interictal hypometabolism in humans is a predictive marker of epileptogenesis, being correlated to the extent and severity of neuronal damage. Among the potential mechanisms underpinning glucose metabolism impairment and the subsequent brain damage, a reduction of cerebral blood flow has been proposed. Accordingly, our goal was to evaluate the potential beneficial effects of naftidrofuryl (25 mg/kg i.p., twice after the insult), a vasodilator drug currently used for circulatory insufficiency-related pathologies. Thus, we measured the effects of naftidrofuryl on the short-term brain hypometabolism and hippocampal damage induced by SE in rats. 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) positron emission tomography (PET) neuroimaging along with various neurohistochemical assays aimed to assess brain damage were performed. SE led to both severe glucose hypometabolism in key epilepsy-related areas and hippocampal neuronal damage. Although naftidrofuryl showed no anticonvulsant properties, it ameliorated the short-term brain hypometabolism induced by pilocarpine. Strikingly, the latter was neither accompanied by neuroprotective nor by anti-inflammatory effects. We suggest that naftidrofuryl, by acutely enhancing brain blood flow around the time of SE improves the brain metabolic state but this effect is not enough to protect from the damage induced by SE.

Functionalization of Morin-Loaded PLGA Nanoparticles with Phenylalanine Dipeptide Targeting the Brain

Alzheimer’s disease (AD) is the most prevalent neurodegenerative disorder, with its incidence constantly increasing. To date, there is no cure for the disease, with a need for new and effective treatments. Morin hydrate (MH) is a naturally occurring flavonoid of the Moraceae family with antioxidant and anti-inflammatory properties; however, the blood–brain barrier (BBB) prevents this flavonoid from reaching the CNS when aiming to potentially treat AD. Seeking to use the LAT-1 transporter present in the BBB, a nanoparticle (NPs) formulation loaded with MH and functionalized with phenylalanine-phenylalanine dipeptide was developed (NPphe-MH) and compared to non-functionalized NPs (NP-MH). In addition, two formulations were prepared using rhodamine B (Rh-B) as a fluorescent dye (NPphe-Rh and NP-Rh) to study their biodistribution and ability to cross the BBB. Functionalization of PLGA NPs resulted in high encapsulation efficiencies for both MH and Rh-B. Studies conducted in Wistar rats showed that the presence of phenylalanine dipeptide in the NPs modified their biodistribution profiles, making them more attractive for both liver and lungs, whereas non-functionalized NPs were predominantly distributed to the spleen. Formulation NPphe-Rh remained in the brain for at least 2 h after administration.

Micro- and Nano-Systems Developed for Tolcapone in Parkinson’s Disease

To date there is no cure for Parkinson’s disease (PD), a devastating neurodegenerative disorder with levodopa being the cornerstone of its treatment. In early PD, levodopa provides a smooth clinical response, but after long-term therapy many patients develop motor complications. Tolcapone (TC) is an effective adjunct in the treatment of PD but has a short elimination half-life. In our work, two new controlled delivery systems of TC consisting of biodegradable PLGA 502 (poly (D,L-lactide-co-glycolide acid) microparticles (MPs) and nanoparticles (NPs) were developed and characterized. Formulations MP-TC4 and NP-TC3 were selected for animal testing. Formulation MP-TC4, prepared with 120 mg TC and 400 mg PLGA 502, exhibited a mean encapsulation efficiency (EE) of 85.13%, and zero-order in vitro release of TC for 30 days, with around 95% of the drug released at this time. Formulation NP-TC3, prepared with 10 mg of TC and 50 mg of PLGA 502, exhibited mean EE of 56.69%, particle size of 182 nm, and controlled the release of TC for 8 days. Daily i.p. (intraperitoneal) doses of rotenone (RT, 2 mg/kg) were given to Wistar rats to induce neurodegeneration. Once established, animals received TC in saline (3 mg/kg/day) or encapsulated within formulations MP-TC4 (amount of MPs equivalent to 3 mg/kg/day TC every 14 days) and NP-TC3 (amount of NPs equivalent to 3 mg/kg/day TC every 3 days). Brain analyses of Nissl-staining, GFAP (glial fibrillary acidic protein), and TH (tyrosine hydroxylase) immunohistochemistry as well as behavioral testing (catalepsy, akinesia, swim test) showed that the best formulation was NP-TC3, which was able to revert PD-like symptoms of neurodegeneration in the animal model assayed.

Significance of Brain Glucose Hypometabolism, Altered Insulin Signal Transduction, and Insulin Resistance in Several Neurological Diseases

Several neurological diseases share pathological alterations, even though they differ in their etiology. Neuroinflammation, altered brain glucose metabolism, oxidative stress, mitochondrial dysfunction and amyloidosis are biological events found in those neurological disorders. Altered insulin-mediated signaling and brain glucose hypometabolism are characteristic signs observed in the brains of patients with certain neurological diseases, but also others such as type 2 diabetes mellitus and vascular diseases. Thus, significant reductions in insulin receptor autophosphorylation and Akt kinase activity, and increased GSK-3 activity and insulin resistance, have been reported in these neurological diseases as contributing to the decline in cognitive function. Supporting this relationship is the fact that nasal and hippocampal insulin administration has been found to improve cognitive function. Additionally, brain glucose hypometabolism precedes the unmistakable clinical manifestations of some of these diseases by years, which may become a useful early biomarker. Deficiencies in the major pathways of oxidative energy metabolism have been reported in patients with several of these neurological diseases, which supports the hypothesis of their metabolic background. This review remarks on the significance of insulin and brain glucose metabolism alterations as keystone common pathogenic substrates for certain neurological diseases, highlighting new potential targets.

99mTc-HMPAO SPECT imaging reveals brain hypoperfusion during status epilepticus

Status epilepticus (SE) is a clinical emergency with high mortality. SE can trigger neuronal death or injury and alteration of neuronal networks resulting in long-term cognitive decline or epilepsy. Among the multiple factors contributing to this damage, imbalance between oxygen and glucose requirements and brain perfusion during SE has been proposed. Herein, we aimed to quantify by neuroimaging the spatiotemporal course of brain perfusion during and after lithium-pilocarpine-induced SE in rats. To this purpose, animals underwent ^99mTc-HMPAO SPECT imaging at different time points during and after SE using a small animal SPECT/CT system. ^99mTc-HMPAO regional uptake was normalized to the injected dose. In addition, voxel-based statistical parametric mapping was performed. SPECT imaging showed an increase of cortical perfusion before clinical seizure activity onset followed by regional hypo-perfusion starting with the first convulsive seizure and during SE. Twenty-four hours after SE, brain ^99mTc-HMPAO uptake was widely decreased. Finally, chronic epileptic animals showed regionally decreased perfusion affecting hippocampus and cortical sub-regions. Despite elevated energy and oxygen requirements, brain hypo-perfusion is present during SE. Our results suggest that insufficient compensation of required blood flow might contribute to neuronal damage and neuroinflammation, and ultimately to chronic epilepsy generated by SE.

PET Neuroimaging Reveals Serotonergic and Metabolic Dysfunctions in the Hippocampal Electrical Kindling Model of Epileptogenesis

Glucose metabolism and serotonergic neurotransmission have been reported to play an important role in epileptogenesis. We therefore aimed to use neuroimaging to evaluate potential alterations in serotonin 5-HT_1A receptor and glucose metabolism during epileptogenesis in the rat electrical kindling model. To achieve this goal, we performed positron emission tomography (PET) imaging in a rat epileptogenesis model triggered by electrical stimulation of the hippocampus using 2-deoxy-2-[¹⁸F]fluoro-D-glucose (¹⁸F-FDG), a radiolabeled analog of glucose, and 2'-methoxyphenyl-(N-2'-pyridinyl)-p-¹⁸F-fluoro-benzamidoethylpiperazine (¹⁸F-MPPF), a radiolabeled 5-HT_1A receptor ligand, to evaluate brain metabolism and 5-HT_1A receptor functionality. Since the 5-HT_1A receptor is also highly expressed in astrocytes, glial fibrillary acidic protein (GFAP) immunofluorescence was performed to detect astrogliosis arising from the kindling procedure once the study was finalized. Lastly, in vitro¹⁸F-MPPF autoradiography was performed to evaluate changes in 5HT_1A receptor expression. ¹⁸F-FDG PET showed reduction of glucose uptake in cortical structures, whereas ¹⁸F-MPPF PET revealed an enhancement of tracer binding potential (BP_ND) in key areas rich in 5-HT_1A receptor involved in epilepsy, including septum, hippocampus and entorhinal cortex of kindled animals compared to controls. However, in vitro 5-HT_1A receptor autoradiography showed no changes in densitometric signal in any brain region, suggesting that the augmentation in BP_ND found by PET could be caused by reduction of synaptic serotonin. Importantly, astroglial activation was detected in the hippocampus of kindled rats. Overall, electrical kindling induced hypometabolism, astrogliosis and serotonergic alterations in epilepsy-related regions. Furthermore, the present findings point to 5-HT_1A receptor as a valuable epileptogenesis biomarker candidate and a potential therapeutic target.

Cannabidiol Enhances the Passage of Lipid Nanocapsules across the Blood-Brain Barrier Both in Vitro and in Vivo

Diseases affecting the central nervous system (CNS) should be regarded as a major health challenge due to the current lack of effective treatments given the hindrance to brain drug delivery imposed by the blood-brain barrier (BBB). Since efficient brain drug delivery should not solely rely on passive targeting, active targeting of nanomedicines into the CNS is being explored. The present study is devoted to the development of lipid nanocapsules (LNCs) decorated with nonpsychotropic cannabinoids as pioneering nonimmunogenic brain-targeting molecules and to the evaluation of their brain-targeting ability both in vitro and in vivo. Noticeably, both the permeability experiments across the hCMEC/D3 cell-based in vitro BBB model and the biodistribution experiments in mice consistently demonstrated that the highest brain-targeting ability was achieved with the smallest-sized cannabinoid-decorated LNCs. Importantly, the enhancement in brain targeting achieved with the conjugation of cannabidiol to LNCs outperformed by 6-fold the enhancement observed for the G-Technology (the main brain active strategy that has already entered clinical trials for the treatment of CNS diseases). As the transport efficiency across the BBB certainly determines the efficacy of the treatments for brain disorders, small cannabinoid-decorated LNCs represent auspicious platforms for the design and development of novel therapies for CNS diseases.

Nanotechnology-based drug delivery of ropinirole for Parkinson's disease

A new drug delivery system is developed for ropinirole (RP) for the treatment of Parkinson’s disease (PD) consisting of biodegradable poly (D,L-lactide-co-glycolide) (PLGA) nanoparticles (NPs). The formulation selected was prepared with 8 mg RP and 50 mg PLGA 502. This formulation exhibited mean encapsulation efficiency of 74.8 ± 8.2%, mean particle size lower than 155 nm, the zeta potential of −14.25 ± 0.43 mV and zero-order in vitro release of RP (14.13 ± 0.17 μg/h/10 mg NPs) for 5 d. Daily doses of the neurotoxin rotenone (2 mg/kg) given i.p. to male Wistar rats induced neuronal and behavioral changes similar to those of PD. Once neurodegeneration was established (15 d) animals received RP in saline (1 mg/kg/d for 35 d) or encapsulated within PLGA NPs (amount of NPs equivalent to 1 mg/kg/d RP every 3 d for 35 d). Brain histology and immunochemistry (Nissl-staining, glial fibrillary acidic protein and tyrosine hydroxylase immunohistochemistry) and behavioral testing (catalepsy, akinesia, rotarod and swim test) showed that RP-loaded PLGA NPs were able to revert PD-like symptoms of neurodegeneration in the animal model assayed.

Metyrapone prevents acute glucose hypermetabolism and short-term brain damage induced by intrahippocampal administration of 4-aminopyridine in rats

Intracerebral administration of the potassium channel blocker 4-aminopyridine (4-AP) triggers neuronal depolarization and intense acute seizure activity followed by neuronal damage. We have recently shown that, in the lithium-pilocarpine rat model of status epilepticus (SE), a single administration of metyrapone, an inhibitor of the 11β-hydroxylase enzyme, had protective properties of preventive nature against signs of brain damage and neuroinflammation. Herein, our aim was to investigate to which extent, pretreatment with metyrapone (150 mg/kg, i.p.) was also able to prevent eventual changes in the acute brain metabolism and short-term neuronal damage induced by intrahippocampal injection of 4-AP (7 μg/5 μl). To this end, regional brain metabolism was assessed by 2-deoxy-2-[¹⁸F]fluoro-d-glucose ([¹⁸F]FDG) positron emission tomography (PET) during the ictal period. Three days later, markers of neuronal death and hippocampal integrity and apoptosis (Nissl staining, NeuN and active caspase-3 immunohistochemistry), neurodegeneration (Fluoro-Jade C labeling), astrogliosis (glial fibrillary acidic protein (GFAP) immunohistochemistry) and microglia-mediated neuroinflammation (in vitro [¹⁸F]GE180 autoradiography) were evaluated. 4-AP administration acutely triggered marked brain hypermetabolism within and around the site of injection as well as short-term signs of brain damage and inflammation. Most important, metyrapone pretreatment was able to reduce ictal hypermetabolism as well as all the markers of brain damage except microglia-mediated neuroinflammation. Overall, our study corroborates the neuroprotective effects of metyrapone against multiple signs of brain damage caused by seizures triggered by 4-AP. Ultimately, our data add up to the consistent protective effect of metyrapone pretreatment reported in other models of neurological disorders of different etiology.

Metyrapone prevents brain damage induced by status epilepticus in the rat lithium-pilocarpine model

The status epilepticus (SE) induced by lithium-pilocarpine is a well characterized rodent model of the human temporal lobe epilepsy (TLE) which is accompanied by severe brain damage. Stress and glucocorticoids markedly contribute to exacerbate neuronal damage induced by seizures but the underlying mechanisms are poorly understood. Herein we sought to investigate whether a single administration of metyrapone (150 mg/kg, i.p.), an 11β-hydroxylase inhibitor, enzyme involved in the peripheral and central synthesis of corticosteroids, had neuroprotective properties in this model. Two experiments were carried out. In exp. 1, metyrapone was administered 3 h before pilocarpine injection whereas in exp. 2, metyrapone administration took place at the onset of the SE. In both experiments, 3 days after the insult, brain metabolism was assessed by in vivo 2-deoxy-2-[¹⁸F]fluoro-d-glucose ([¹⁸F]FDG) positron emission tomography (PET). Brains were processed for analyses of markers of hippocampal integrity (Nissl staining), neurodegeneration (Fluoro-Jade C), astrogliosis (glial fibrillary acidic protein (GFAP) immunohistochemistry) and, for a marker of activated microglia by in vitro autoradiography with the TSPO (18 kDa translocator protein) radioligand [¹⁸F]GE180. The SE resulted in a consistent hypometabolism in hippocampus, cortex and striatum and neuronal damage, hippocampal neurodegeneration, neuronal death and gliosis. Interestingly, metyrapone had neuroprotective effects when administered before, but not after the insult. In summary, we conclude that metyrapone administration prior but not after the SE protected from brain damage induced by SE in the lithium-pilocarpine model. Therefore, it seems that the effect of metyrapone is preventive in nature and likely related to its antiseizure properties.

Surface-modified gatifloxacin nanoparticles with potential for treating central nervous system tuberculosis

A new nanocarrier is developed for the passage of gatifloxacin through the blood-brain barrier to treat central nervous system tuberculosis. Gatifloxacin nanoparticles were prepared by nanoprecipitation using poly(lactic-co-glycolic acid) (PLGA) 502 and polysorbate 80 or Labrafil as surface modifiers. The evaluation of in vivo blood-brain barrier transport was carried out in male Wistar rats using rhodamine-loaded PLGA nanoparticles prepared with and without the surface modifiers. At 30 and 60 minutes after administration, nanoparticle biodistribution into the brain (hippocampus and cortex), lungs, and liver was studied. The results obtained from the cerebral cortex and hippocampus showed that functionalization of rhodamine nanoparticles significantly increased their passage into the central nervous system. At 60 minutes, rhodamine concentrations decreased in both the lungs and the liver but were still high in the cerebral cortex. To distinguish the effect between the surfactants, gatifloxacin-loaded PLGA nanoparticles were prepared. The best results corresponded to the formulation prepared with polysorbate 80 with regard to encapsulation efficiency (28.2%), particle size (176.5 nm), and ζ-potential (-20.1 mV), thereby resulting in a promising drug delivery system to treat cerebral tuberculosis.

Dysregulation of the endocannabinoid signaling system in the cerebellum and brainstem in a transgenic mouse model of spinocerebellar ataxia type-3

Spinocerebellar ataxia type-3 (SCA-3) is a rare disease but it is the most frequent type within the autosomal dominant inherited ataxias. The disease lacks an effective treatment to alleviate major symptoms and to modify disease progression. Our recent findings that endocannabinoid receptors and enzymes are significantly altered in the post-mortem cerebellum of patients affected by autosomal-dominant hereditary ataxias suggest that targeting the endocannabinoid signaling system may be a promising therapeutic option. Our goal was to investigate the status of the endocannabinoid signaling system in a transgenic mouse model of SCA-3, in the two CNS structures most affected in this disease - cerebellum and brainstem. These animals exhibited progressive motor incoordination, imbalance, abnormal gait, muscle weakness, and dystonia, in parallel to reduced in vivo brain glucose metabolism, deterioration of specific neuron subsets located in the dentate nucleus and pontine nuclei, small changes in microglial morphology, and reduction in glial glutamate transporters. Concerning the endocannabinoid signaling, our data indicated no changes in CB₂ receptors. By contrast, CB₁ receptors increased in the Purkinje cell layer, in particular in terminals of basket cells, but they were reduced in the dentate nucleus. We also measured the levels of endocannabinoid lipids and found reductions in anandamide and oleoylethanolamide in the brainstem. These changes correlated with an increase in the FAAH enzyme in the brainstem, which also occurred in some cerebellar areas, whereas other endocannabinoid-related enzymes were not altered. Collectively, our results in SCA-3 mutant mice confirm a possible dysregulation in the endocannabinoid system in the most important brain structures affected in this type of ataxia, suggesting that a pharmacological manipulation addressed to correct these changes could be a promising option in SCA-3.

Stimulation of brain glucose uptake by cannabinoid CB2 receptors and its therapeutic potential in Alzheimer's disease

Cannabinoid CB2 receptors (CB2Rs) are emerging as important therapeutic targets in brain disorders that typically involve neurometabolic alterations. We here addressed the possible role of CB2Rs in the regulation of glucose uptake in the mouse brain. To that aim, we have undertaken 1) measurement of (3)H-deoxyglucose uptake in cultured cortical astrocytes and neurons and in acute hippocampal slices; 2) real-time visualization of fluorescently labeled deoxyglucose uptake in superfused hippocampal slices; and 3) in vivo PET imaging of cerebral (18)F-fluorodeoxyglucose uptake. We now show that both selective (JWH133 and GP1a) as well as non-selective (WIN55212-2) CB2R agonists, but not the CB1R-selective agonist, ACEA, stimulate glucose uptake, in a manner that is sensitive to the CB2R-selective antagonist, AM630. Glucose uptake is stimulated in astrocytes and neurons in culture, in acute hippocampal slices, in different brain areas of young adult male C57Bl/6j and CD-1 mice, as well as in middle-aged C57Bl/6j mice. Among the endocannabinoid metabolizing enzymes, the selective inhibition of COX-2, rather than that of FAAH, MAGL or α,βDH6/12, also stimulates the uptake of glucose in hippocampal slices of middle-aged mice, an effect that was again prevented by AM630. However, we found the levels of the endocannabinoid, anandamide reduced in the hippocampus of TgAPP-2576 mice (a model of β-amyloidosis), and likely as a consequence, COX-2 inhibition failed to stimulate glucose uptake in these mice. Together, these results reveal a novel general glucoregulatory role for CB2Rs in the brain, raising therapeutic interest in CB2R agonists as nootropic agents.

Short-term fluoxetine treatment induces neuroendocrine and behavioral anxiogenic-like responses in adolescent male rats

Fluoxetine (FLX) is prescribed to treat depression and anxiety in adolescent patients. However, FLX has anxiogenic effects during the acute phase of treatment, and caution has been raised due to increased suicidal thinking and behavior. Herein, we sought to study in adolescent (35-day-old) male rats, the effects of short-term FLX treatment (10 mg/kg/day, i.p. for 3-4 days) on hypothalamic-pituitary-adrenal axis activity, serotonin (5-hidroxytriptamine, 5-HT) transporter (SERT) mRNA expression in the dorsal raphe nucleus (DRN), energy balance-related variables and behavioral profiles in the holeboard. Our results revealed that daily FLX administration increased plasma corticosterone (B) concentrations without affecting basal gene expression of corticotrophin releasing hormone in the hypothalamic paraventricular nucleus (PVN) nor of pro-opiomelanocortin in the anterior pituitary. However, FLX had significant effects increasing the mRNA expression of PVN arginine vasopressin (AVP) and reducing SERT mRNA levels in the dorsolateral subdivision of the DRN. In the holeboard, FLX-induced anxiety/emotionality-like behaviors. As expected, FLX treatment was endowed with anorectic effects and reduced body weight gain. Altogether, our study shows that short-term FLX treatment results in physiological, neuroendocrine and behavioral stress-like effects in adolescent male rats. More importantly, considering that the AVP- and 5-HTergic systems: (1) are intimately involved in regulation of the stress response; (2) are regulated by sex hormones and (3) are related to regulation of aggressive behaviors, our results highlight the potential significance of these systems mediating the anxiogenic/emotionality/stress-like responses of adolescent male rats to short-term FLX treatment.

N-(4-[(18)F]-fluoropyridin-2-yl)-N-{2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl}carboxamides as analogs of WAY100635. New PET tracers of serotonin 5-HT(1A) receptors

N-(4-[(18)F]-Fluoropyridin-2-yl)-N-{2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl}-carboxamides were prepared by labeling their 4-nitropyridin-2-yl precursors through nitro substitution by the (18)F anion. In vitro and in vivo tests showed that the cyclohexanecarboxamide derivative is a reversible, selective and high affinity 5-HT1A receptor antagonist (IC50 = 0.29 nM, ki = 0.18 nM) with high brain uptake, slow brain clearance and stability to defluorination when compared with conventional standards. This PET radioligand is a promising candidate for an improved in vivo quantification of 5-HT1A receptors in neuropsychiatric disorders.

Neuroprotective Properties of Standardized Extracts of Hypericum perforatum on Rotenone Model of Parkinson's Disease

Hipericum perforatum is a well-known herbal for its antidepressant property. Recently, it has been shown to have nootropic effects against neurodegenerative disorders. The aim of the present study was to evaluate the protective role of chronic administration of two standardized extract of Hypericum perforatum SHP1 rich in hyperforin (6%) and SHP2 extract poor in hyperforin (0.2%) on the neurodegeneration induced by chronic administration of rotenone in rats. Quercetin in liposomes, one active constituent, was tested in the same experimental conditions. The animals received pretreatments with SHP1 (4 mg/Kg, ip), SHP2 (4 mg/Kg, ip) or quercetin liposomes (25 and 100 mg/kg, ip) 60 min before of rotenone injection (2.5 mg/kg) for 45 days. Pretreatment of the animals with SHP1 and SHP2 efficiently halted deleterious toxic effects of rotenone, revealing normalization of catalepsy in addition to amelioration of neurochemical parameters. Also, SHP1 reduced neuronal damage, diminishing substantia nigra dopaminergic cell death caused by the pesticide, indicating benefit of neuroprotective therapy. In general, the SHP1 was more active than SHP2. In addition, SHP1 inhibited the apoptotic cascade by decreasing Bax levels. The results presented here indicate that mainly hyperforin and quercetin, may be involved in the neuroprotective action of Hypericum standardized extracts. Combination of dietary antioxidants could provide better therapeutic advantage for the management of Parkinson, and possibly other neurodegenerative disorders. Therefore H. perforatum standardized extract enriched in hyperforin, could be a better alternative for depressed elderly patients with degenerative disorders exhibiting elevated oxidative stress status.

Prolonged oral cannabinoid administration prevents neuroinflammation, lowers β-amyloid levels and improves cognitive performance in Tg APP 2576 mice

Background

Alzheimer's disease (AD) brain shows an ongoing inflammatory condition and non-steroidal anti-inflammatories diminish the risk of suffering the neurologic disease. Cannabinoids are neuroprotective and anti-inflammatory agents with therapeutic potential.

Methods

We have studied the effects of prolonged oral administration of transgenic amyloid precursor protein (APP) mice with two pharmacologically different cannabinoids (WIN 55,212-2 and JWH-133, 0.2 mg/kg/day in the drinking water during 4 months) on inflammatory and cognitive parameters, and on ¹⁸F-fluoro-deoxyglucose (¹⁸FDG) uptake by positron emission tomography (PET).

Results

Novel object recognition was significantly reduced in 11 month old Tg APP mice and 4 month administration of JWH was able to normalize this cognitive deficit, although WIN was ineffective. Wild type mice cognitive performance was unaltered by cannabinoid administration. Tg APP mice showed decreased ¹⁸FDG uptake in hippocampus and cortical regions, which was counteracted by oral JWH treatment. Hippocampal GFAP immunoreactivity and cortical protein expression was unaffected by genotype or treatment. In contrast, the density of Iba1 positive microglia was increased in Tg APP mice, and normalized following JWH chronic treatment. Both cannabinoids were effective at reducing the enhancement of COX-2 protein levels and TNF-α mRNA expression found in the AD model. Increased cortical β-amyloid (Aβ) levels were significantly reduced in the mouse model by both cannabinoids. Noteworthy both cannabinoids enhanced Aβ transport across choroid plexus cells in vitro.

Conclusions

In summary we have shown that chronically administered cannabinoid showed marked beneficial effects concomitant with inflammation reduction and increased Aβ clearance.

Longitudinal studies of ischemic penumbra by using 18F-FDG PET and MRI techniques in permanent and transient focal cerebral ischemia in rats

At present, the goal of stroke research is the identification of a potential recoverable tissue surrounding the ischemic core, suggested as ischemic penumbra, with the aim of applying a treatment that attenuates the growth of this area. Our purpose was to determine whether a combination of imaging techniques, including (18)F-FDG PET and MRI could identify the penumbra area. Longitudinal studies of (18)F-FDG PET and MRI were performed in rats 3 h, 24 h and 48 h after the onset of ischemia. A transient and a permanent model of focal cerebral ischemia were performed. Regions of interest were located, covering the ischemic core, the border that progresses to infarction (recruited tissue), and the border that recovers (recoverable tissue) with early reperfusion. Analyses show that permanent ischemia produces severe damage, whereas the transient ischemia model does not produce clear damage in ADC maps at the earliest time studied. The only significant differences between values for recoverable tissue, (18)F-FDG (84±2%), ADC (108±5%) and PWI (70±8%), and recruited tissue, (18)F-FDG (77±3%), ADC (109±4%) and PWI (77±4%), are shown in (18)F-FDG ratios. We also show that recoverable tissue values are different from those in non-infarcted tissue. The combination of (18)F-FDG PET, ADC and PWI MRI is useful for identification of ischemic penumbra, with (18)F-FDG PET being the most sensitive approach to its study at early times after stroke, when a clear DWI deficit is not observed.

Using national health weeks to deliver deworming to children: lessons from Mexico

Mexico established national health weeks (NHWs) in the early 1980s to promote childhood vaccinations. Because of the cumulative worldwide peer-reviewed scientific evidence, the recommendations of the World Health Organization and other international organisations, the political will of the Mexican government and the infrastructure provided by the NHWs, deworming was added to the NHWs in 1993. In addition to the Ministry of Health, several other government organisations participated in administering the deworming component. Tens of millions of school-age and preschool children between the ages of 2 years and 14 years now receive deworming (a single 400 mg dose of albendazole) approximately every 8 months. Between 1993 and 1998 evaluations were carried out in over 90,000 children to determine the effect of NHWs on the prevalence of geohelminth infections. In 1993, the overall prevalence of Ascaris was 20% and that of Trichuris was 15%. Prevalences decreased significantly over time (p <0.001). Treatment efficacy for Ascaris ranged from 91.6% to 85.3%, and for Trichuris, from 97.9% to 42.6%. In 1998, after conducting 12 NHWs with deworming, the respective prevalences were Ascaris 8% and Trichuris 11%. The experience of Mexico in integrating albendazole into its NHWs shows how deworming can be delivered to large numbers of at-risk children using an existing infrastructure. The NHW approach may be generalisable in other countries with successful national vaccination campaigns. The challenge remaining is to sustain the deworming programme until other longer-term behavioural, environmental and socioeconomic changes can be implemented.

[A pilot study of endoscopic experimental transgastric peritoneoscopy and endoscopic gastrorrhaphy in a canine model.]

BACKGROUND AND AIMS

Natural Orifice Translumenal Endoscopic Surgery (NOTES) is an experimental technique with potential advantages compared to laparoscopic surgery. Trans gastric peritoneoscopy (TP) is a NOTES technique. The aim of this study was to perform TP, to evaluate feasibility and technical limitations in a survival model.

MATERIALS AND METHODS

The following procedures were performed in 4 anesthetized dogs using a single channel video gastroscope: Gastrotomy with needle-knife puncture followed with extension of the incision with a pull-type sphincterotome,pneumoperitoneum with the endoscope,peritoneoscopy and gastrorrhapy using hemoclips and endoloops.

RESULTS

All the procedures were accomplished successfully with a mean duration of 80 minutes. Gastrotomy induced minor bleeding.Peritoneal cavity was accessed safely and peritoneoscopy was accomplished without incidents.Retroflexed maneuvers were mandatory to visualize upper abdomen and overinflation oftenly occurred. The closure of the gastric wall incision was successfully obtained. All the animals made an uncomplicated recovery after 7 days.

CONCLUSIONS

TP is technically feasible and safe in a canine model. This study highlights several technical limitations and confirms the need for technological development.

Gender differentials of pulmonary tuberculosis transmission and reactivation in an endemic area

BACKGROUND

In most low income countries there are twice as many cases of tuberculosis (TB) reported among men than among women, a difference commonly attributed to biological and epidemiological characteristics as well as socioeconomic and cultural barriers in access to health care. The World Health Organization has encouraged gender specific comparisons in TB rates to determine whether women with TB are less likely than men with TB to be diagnosed, reported, and treated. A study was undertaken to identify gender based differences in patients with pulmonary TB and to use this information to improve TB control efforts.

METHODS

Individuals with a cough for more than 2 weeks in southern Mexico were screened from March 1995 to April 2003. Clinical and mycobacteriological information (isolation, identification, drug susceptibility testing and IS6110 based genotyping, and spoligotyping) was collected from those with bacteriologically confirmed pulmonary TB. Patients were treated in accordance with official norms and followed to ascertain treatment outcome, retreatment, and vital status.

RESULTS

623 patients with pulmonary TB were enrolled. The male:female incidence rate ratio for overall, reactivated, and recently transmitted disease was 1.58 (95% CI 1.34 to 1.86), 1.64 (95% CI 1.36 to 1.98), and 1.41 (95% CI 1.01 to 1.96), respectively. Men were more likely than women to default from treatment (adjusted OR 3.30, 95% CI 1.46 to 7.43), to be retreated (hazard ratio (HR) 3.15, 95% CI 1.38 to 7.22), and to die from TB (HR 2.23, 95% CI 1.25 to 3.99).

CONCLUSIONS

Higher rates of transmitted and reactivated disease and poorer treatment outcomes among men are indicators of gender differentials in the diagnosis and treatment of pulmonary TB, and suggest specific strategies in endemic settings.

Stenting as first option for endovascular treatment of malignant superior vena cava syndrome

OBJECTIVE

Endoprostheses were inserted in cancer patients with superior vena cava syndrome to assess their effectiveness as first-choice, initial treatment for relief of symptoms.

SUBJECTS AND METHODS

Wallstent prostheses (n = 73) of various lengths (5-14 cm; median, 7 cm) and diameters (10-16 mm; median, 16 mm) were inserted in 52 cancer patients (51 men, 1 woman; age range, 44-78 years; mean, 63 years) who were diagnosed and confirmed by cavography or phlebography as having superior vena cava syndrome. A single stent was sufficient in 37 patients, two stents were required in 11, three stents in two, and four stents in another two patients. Contraindications for the procedure were severe cardiopathy or coagulopathy.

RESULTS

Resolution of symptoms was achieved in all patients within 72 hr. At follow-up, six obstructions, one partial migration to the right atrium, two incorrect placements, and four stent "shortenings" were noted. All were successfully resolved by repeated stenting. Symptom-free survival ranged from 2 days to 17 months (mean, 6.4 months). At the time of this writing, eight patients are alive and have patent stents. The rest have died from their cancer.

CONCLUSION

The Wallstent vascular endoprosthesis is an effective initial treatment in superior vena cava syndrome of neoplastic origin. Morbidity and complications are minimal. Clinical relief of symptoms is rapid; therefore, the Wallstent endoprosthesis is highly recommended as the first choice for palliative treatment of superior vena cava syndrome, especially because the clinical decision for subsequent chemotherapy or radiotherapy or surgery is not in any way prejudiced.

RU-486 blocks stress-induced enhancement of proenkephalin gene expression in the paraventricular nucleus of rat hypothalamus

The purpose of this study was to investigate the glucocorticoid (GC) mediated regulation of corticotropin-releasing hormone (CRH) and proenkephalin (PE) gene expressions in the paraventricular nucleus (PVN) of the hypothalamus during physical stress induced by a single intraperitoneal (i.p.) injection of hypertonic saline (9% NaCl). Previous intracerebroventricular (i.c.v.) administration of the type II glucocorticoid receptor (GR) antagonist RU-486 (20 ng/rat), increased the basal CRH mRNA levels in the PVN but had no effect on PE gene expression. Stress induced by injection of hypertonic saline increased both CRH and PE mRNA levels in PVN. Administration of RU-486 completely blocked the stress-induced increase of PE mRNA levels, but failed to alter the CRH mRNA levels in the PNV. These data suggests that, under these experimental conditions, endogenous GC are necessary for a normal PE response to hypertonic saline stress.

Differential 5-HT-mediated regulation of stress-induced activation of proopiomelanocortin (POMC) gene expression in the anterior and intermediate lobe of the pituitary in male rats

The purpose of the present study was to examine the role of 5-hydroxytryptamine (5-HT) neurons in mediating the effects of stress on proopiomelanocortin (POMC) gene expression in the anterior and intermediate lobes of the pituitary gland. To this aim, the effects of 5-HT depletion induced by administration of the neurotoxin 5,7-dihydroxytryptamine (5,7-DHT; 200 microg/rat; i.c.v.; 7 days) were investigated on POMC mRNA levels in the anterior and intermediate lobe of control and restraint-stressed rats. Three hours after brief exposure to diethyl ether (2 min) followed by 60 min of restraint stress increased POMC mRNA levels in the anterior and intermediate lobe of the pituitary. 5,7-DHT neurotoxic lesion, which resulted in a marked depletion of 5-HT (below the level of sensitivity of the neurochemical assay, 6 pg/sample) but not of dopamine or norepinephrine concentrations in the periventricular nucleus of the hypothalamus, had no effect on basal POMC mRNA levels in the anterior or intermediate lobe of the pituitary. However, 5-HT depletion further increased POMC mRNA levels in the anterior pituitary and completely blocked POMC mRNA level enhancement induced in the intermediate lobe of stressed rats. These results suggest a possible inhibitory 5-HT tone on POMC gene expression in the anterior pituitary and a stimulatory 5-HT tone in the intermediate lobe of the pituitary under these experimental conditions of stress. It appears, therefore, that 5-HT exerts a differential regulation of stress-induced activation of POMC gene expression in the anterior and intermediate lobes of the pituitary in male rats.

[VDRL and FTA-ABS reactivity in cerebrospinal fluid: our experience]

The reactivity of 194 samples of CSF against VDRL and FTA-ABS was studied in patients attending the Clinical Hospital in Salamanca over a five years period. This laboratory was asked to rule out an etiology of syphilis. Twelve samples of CSF proved to be reactive (6.2%) against VDRL and/or FTA-ABS. Seven of these corresponded to six adults diagnosed as suffering from neurosyphilis and one to an infant with early congenital syphilis without neurological alterations; these had in common the presence of active syphilis and a reactive FTA-ABS in serum. In the CSF of the six cases of neurosyphilis, VDRL was reactive in two patients (33.3%) and FTA-ABS in five (83.3%). One minimally reactive VDRL and four FTA-ABS were detected in the remaining five patients, with no known previous history of syphilis, that were suffering from different neurological alterations and that had a nonreactive FTA-ABS in serum. The results obtained in this study point to inappropriate use in CSF of VDRL and FTA-ABS to exclude neurosyphilis in our hospital since only 3.6% of the CSF studied corresponded to patients diagnosed as suffering from neurosyphilis and also to the need for improving the criteria for patient selection.