Enrique Echevarría

Distribution and neurochemical characterization of neurons expressing GIRK channels in the rat brain

G‐protein inwardly rectifying potassium (GIRK) channels mediate the synaptic actions of numerous neurotransmitters in the mammalian brain and play an important role in the regulation of neuronal excitability in most brain regions through activation of various G‐protein‐coupled receptors such as the serotonin 5‐HT1A receptor. In this report we describe the localization of GIRK1, GIRK2, and GIRK3 subunits and 5‐HT1A receptor in the rat brain, as assessed by immunohistochemistry and in situ hybridization. We also analyze the co‐expression of GIRK subunits with the 5‐HT1A receptor and cell markers of glutamatergic, γ‐aminobutyric acid (GABA)ergic, cholinergic, and serotonergic neurons in different brain areas by double‐label in situ hybridization. The three GIRK subunits are widely distributed throughout the brain, with an overlapping expression in cerebral cortex, hippocampus, paraventricular nucleus, supraoptic nucleus, thalamic nuclei, pontine nuclei, and granular layer of the cerebellum. Double‐labeling experiments show that GIRK subunits are present in most of the 5‐HT1A receptor‐expressing cells in hippocampus, cerebral cortex, septum, and dorsal raphe nucleus. Similarly, GIRK mRNA subunits are found in glutamatergic and GABAergic neurons in hippocampus, cerebral cortex, and thalamus, in cholinergic cells in the nucleus of vertical limb of the diagonal band, and in serotonergic cells in the dorsal raphe nucleus. These results provide a deeper knowledge of the distribution of GIRK channels in different cell subtypes in the rat brain and might help to elucidate their physiological roles and to evaluate their potential involvement in human diseases. J. Comp. Neurol. 510:581–606, 2008.

Cognitive impairment is related to oxidative stress and chemokine levels in first psychotic episodes

INTRODUCTION This study measures the levels of various markers of oxidative stress and inflammation in blood samples from first-episode psychosis (FEP) patients, and examines the association between these peripheral biomarkers and cognitive performance at 6 months after treatment. METHODS Twenty-eight FEP patients and 28 healthy controls (matched by age, sex and educational level) had blood samples taken at admission for assessment of total antioxidant status, superoxide dismutase (SOD), total glutathione (GSH), catalase (CAT), glutathione peroxidase, lipid peroxidation, nitrites and the chemokine monocyte chemoattractant protein-1 (MCP-1). A battery of cognitive tests was also applied to the healthy controls and those FEP patients who were in remission at 6 months after the acute episode. RESULTS FEP patients had significantly lower levels of total antioxidant status, catalase and glutathione peroxidase, compared with the healthy controls. Regression analyses found that MCP-1 levels were negatively associated with learning and memory (verbal and working), nitrite levels were negatively associated with executive function, and glutathione levels were positively associated with executive function. CONCLUSION Our results suggest an association between certain peripheral markers of oxidative stress and inflammation and specific aspects of cognitive functioning in FEP patients. Further studies on the association between MCP-1 and cognition are warranted.

Solid lipid nanoparticles as potential tools for gene therapy: in vivo protein expression after intravenous administration.

Naked plasmid DNA is a powerful tool for gene therapy, but it is rapidly eliminated from the circulation after intravenous administration. Therefore, the development of optimized DNA delivery systems is necessary for its successful clinical use. Solid lipid nanoparticles (SLNs) have demonstrated transfection capacity in vitro, but their application for gene delivery has not been conveniently investigated in vivo. We aimed to evaluate the capacity of SLN-DNA vectors to transfect in vivo after intravenous administration to mice. The SLNs, composed of Precirol ATO 5, DOTAP and Tween 80 were complexed with the plasmid pCMS-EGFP which encodes the enhanced green fluorescent protein (EGFP). The resulting systems were characterized in vitro showing a mean particle size of 276 nm, superficial charge of +28 mV, the ability to protect the plasmid and transfection capacity in culture cells. The intravenous administration in mice led to transfection in hepatic tissue and spleen. Protein expression was detected from the third day after administration, and it was maintained for at least 1 week. This work shows for the first time the capacity of SLN-DNA vectors to induce the expression of a foreign protein after intravenous administration, supporting the potential of SLNs for gene therapy.

Dextran-protamine-solid lipid nanoparticles as a non-viral vector for gene therapy: in vitro characterization and in vivo transfection after intravenous administration to mice.

The aim of present work is to evaluate the transfection capacity of a new multicomponent system based on dextran (Dex), protamine (Prot), and solid lipid nanoparticles (SLN) after intravenous administration to mice. The vectors containing the pCMS-EGFP plasmid were characterized in terms of particle size and surface charge. In vitro transfection capacity and cell viability were studied in four cell lines, and compared with the transfection capacity of SLN without dextran and protamine. Transfection capacity was related to the endocytosis mechanism: caveolae or clathrin. The Dex-Prot-DNA-SLN vector showed a higher transfection capacity in those cells with a high ratio of activity of clathrin/caveolae-mediated endocytosis. However, the complex prepared without dextran and protamine (DNA-SLN) was more effective in those cells with a high ratio of activity of caveolae/clathrin-mediated endocytosis. The interaction with erythrocytes and the potential hemolytic effect were also checked. The Dex-Prot-DNA-SLN vector showed no agglutination of erythrocytes, probably due to the presence of dextran. After intravenous administration to BALB/c mice, the vector was able to induce the expression of the green fluorescent protein in liver, spleen and lungs, and the protein expression was maintained for at least 7 days. Although additional studies are necessary, this work reveals the promising potential of this new gene delivery system for the treatment of genetic and non-genetic diseases through gene therapy.

A long‐term physical activity training program increases strength and flexibility, and improves balance in older adults

Purpose: Physical activity training programs in older adults have recognized health benefits. Evidence suggests that training should include a combination of progressive resistance, balance, and functional training. Our aim was to assess the effects of a simple physical activity program working on strength, flexibility, cardiovascular fitness, and balance in older adults, as well as the effects of a detraining period, at various different ages. Methods: This was longitudinal prospective study, including a convenience sample of 227 independent older adults (54 men, 173 women) who completed a simple 9‐month training program and 3‐month detraining follow‐up. The subjects were categorized into two age groups (65–74 [n = 180], and >74 years [n = 47]). At the beginning of the study (baseline), the end of the training period, and 3 months later (postdetraining), body mass index, body fat percentage, triceps skinfold thickness, hand grip strength, lower limb and trunk flexibility, resting heart rate, heart rate after exercise, and balance were measured, while VO2 max was estimated using the Rockport fitness test and/or measured directly. Results: Significant improvements in strength (p < .0001), flexibility (p < .0001), heart rate after exercise (p < .0001), and balance (p < .0001) were observed at the end of the training program. Flexibility and balance (p < .0001) improvements were maintained at the end of the detraining. Conclusion: A simple long‐term physical activity training program increases strength in both sexes, improves flexibility in women, and improves balance in older adults. The results also indicate the importance of beginning early in old age and maintaining long‐term training.

In-patient care costs of patients with bipolar I disorder: A comparison between two European centers

BACKGROUND Bipolar disorder (BPD) is a disabling disease with high morbidity rates. An international (Spain, France) comparative study about hospitalizations and in-patient care costs associated with BPD I was performed. Centers were included if they had access to a database of computerized patient charts exhaustively covering a defined catchment area. METHODS Economic evaluation was performed by multiplying the average cumulated annual length of stay (LOS) of hospitalized bipolar patients by a full cost per day of hospitalization in each center to obtain the corresponding annual costs. RESULTS Hospitalization rates per annum and per 100,000 individuals (general population aged 15+) were similar between France (43.6) and Spain (43.1). There were only slight differences in relation to length of stay (LOS) per patient hospitalized with 18.1 days in Spain and 20.4 days in France. The overall estimated annual hospitalization costs were in the same order of magnitude after adjustment to an adult population of 100,000: euro 232,000 (Spain) and euro 226,500 (France). Mixed episodes had the longest LOS followed by depressive episodes, while manic episodes had the shortest ones. Mania was the most costly disorder representing 53.7% of annual BPD in-patient care costs. CONCLUSIONS BPD I care requires large resources and frequent hospitalizations, especially during manic episodes. Depressive and mixed episodes require longer hospital stays than manic episodes. Out-patient costs should now be evaluated.

Effects of fluoxetine administration on mu-opoid receptor immunostaining in the rat forebrain

Fluoxetine is a selective serotonin reuptake inhibitor. Analysis of mu-opioid receptor immunostaining after chronic fluoxetine administration in rats revealed an increase in the density of cells expressing mu-opioid receptors in the caudatus-putamen, the dentate gyrus, the lateral septum and the frontal, parietal and piriform cortices. These data suggest that mu-opioid receptor expression in the rat forebrain is altered by in vivo chronic fluoxetine treatment.

Adaptive response in the antioxidant defence system in the course and outcome in first-episode schizophrenia patients: A 12-months follow-up study

Correlation of plasma antioxidant enzyme activity with the course and outcome in first-episode schizophrenia patients (n=49) was analyzed in order to assess the possible utility of peripheral markers of oxidative stress as prognostic factors. These markers were measured shortly after the onset of schizophrenia, and again 1, 6 and 12 months later. A decrease in catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), and glutathione (GSH) levels and total antioxidant status (TAS), as well as an increase in thiobarbituric acid reactive substances (TBARS), were observed 1 month after (p<0.05). 6-Months later, there was a reduction in TAS, GSH, SOD and GPx, and a increase in TBARS (p<0.05), with a normalization of CAT levels, indicating a persistent alteration of the antioxidant system and the maintenance of oxidative stress. At 12-months, a considerable decrease was observed in TBARS. Additionally, while the level of GPx decreased (p<0.05) further, SOD and GSH levels and TAS were normalizing, indicating a partial regeneration of the antioxidant defence system. These results indicate the possible contribution of oxidative stress to the onset and pathophysiology of schizophrenia, suggesting the involvement of an adaptive response in the antioxidant defence system in the course and outcome in first-episode schizophrenia patients.

Lithium alters mu-opioid receptor expression in the rat brain.

Lithium can potentiate the effects of antidepressant drugs and alters morphine analgesia and phosphoinositide turnover. Analysis of mu-opioid receptor immunostaining after chronic lithium administration in rats revealed an increase in the density of cells expressing mu-opioid receptors in the caudatus-putamen, the dentate gyrus, the lateral septum and the frontal, parietal and piriform cortices. These data suggest that mu-opioid receptor expression in the rat forebrain is altered by in vivo chronic lithium treatment. This could be a compensatory mechanism, induced in part by the effects of lithium on mu-opioid receptor transduction mechanism.

Heat makes a difference in activity‐based anorexia: A translational approach to treatment development in anorexia nervosa

OBJECTIVE To test the effect of raising ambient temperature (AT) on activity-based anorexia (ABA) and to extend to female rats previous findings reported in male animals. METHOD Two studies are reported in which female rats were submitted to food restriction and free access to an activity wheel either separately or in combination under changing (21-32 °C) or constant AT (21 °C). RESULTS Warming ABA animals reversed running activity, preserved food-intake, and enabled female rats to recover from acute weight loss. Moreover, sedentary food-restricted warmed rats maintained a body weight equivalent to the levels of animals housed at standard AT in spite of 20% reduced food-intake. DISCUSSION The replication on female rats corroborates the effect previously reported for males, which is indicative of the robust effect of AT in recovering rats from ABA. The findings reported here represent strong preclinical evidence in favor of heat supply as a useful adjunctive component for the treatment of anorexia nervosa (AN).