Cytokine pathway disruption in a mouse model of schizophrenia induced by Munc18-1a overexpression in the brain.

BACKGROUND: An accumulating body of evidence points to the significance of neuroinflammation and immunogenetics in schizophrenia, and an imbalance of cytokines in the central nervous system (CNS) has been suggested to be associated with the disorder. Munc18-overexpressing mice (Munc18-OE) have provided a model for the study of the alterations that may underlie the symptoms of subjects with schizophrenia. The aim of the present study was to elucidate the involvement of neuroinflammation and cytokine imbalance in this model. METHODS: Cytokines were evaluated in the cortex and the striatum of Munc18-OE and wild-type (WT) mice by enzyme-linked immunosorbent assay (ELISA). Protein levels of specific microglia and macrophage, astrocytic and neuroinflammation markers were quantified by western blot in the cortex and the striatum of Munc18-OE and WT mice. RESULTS: Each cytokine evaluated (Interferon-gamma (IFN-γ), Tumor Necrosis Factor-alpha (TNF-α), Interleukin-2 (IL-2) and CCL2 chemokine) was present at higher levels in the striatum of Munc18-OE mice than WT. Cortical TNF-α and IL-2 levels were significantly lower in Munc18-OE mice than WT mice. The microglia and macrophage marker CD11b was lower in the cortexes of Munc18-OE mice than WT, but no differences were observed in the striatum. Glial Fibrillary Acidic Protein (GFAP) and Nuclear Factor-kappaB (NF-κB)p65 levels were not different between the groups. Interleukin-1beta (IL-1ß) and IL-6 levels were beneath detection limits. CONCLUSIONS: The disrupted levels of cytokines detected in the brain of Munc18-OE mice was found to be similar to clinical reports and endorses study of this type for analysis of this aspect of the disorder. The lower CD11b expression in the cortex but not in the striatum of the Munc18-OE mice may reflect differences in physiological activity. The cytokine expression pattern observed in Munc18-OE mice is similar to a previously published model of schizophrenia caused by maternal immune activation. Together, these data suggest a possible role for an immune imbalance in this disorder.

Maternal Immune Activation Induces Cortical Catecholaminergic Hypofunction and Cognitive Impairments in Offspring.

BACKGROUND: Impairment of specific cognitive domains in schizophrenia has been associated with prefrontal cortex (PFC) catecholaminergic deficits. Among other factors, prenatal exposure to infections represents an environmental risk factor for schizophrenia development in adulthood. However, it remains largely unknown whether the prenatal infection-induced changes in the brain may be associated with concrete switches in a particular neurochemical circuit, and therefore, if they could alter behavioral functions. METHODS: In vitro and in vivo neurochemical evaluation of the PFC catecholaminergic systems was performed in offspring from mice undergoing maternal immune activation (MIA). The cognitive status was also evaluated. Prenatal viral infection was mimicked by polyriboinosinic-polyribocytidylic acid (poly(I:C)) administration to pregnant dams (7.5 mg/kg i.p., gestational day 9.5) and consequences were evaluated in adult offspring. RESULTS: MIA-treated offspring showed disrupted recognition memory in the novel object recognition task (t = 2.30, p = 0.031). This poly(I:C)-based group displayed decreased extracellular dopamine (DA) concentrations compared to controls (t = 3.17, p = 0.0068). Potassium-evoked release of DA and noradrenaline (NA) were impaired in the poly(I:C) group (DA: Ft[10,90] = 43.33, p < 0.0001; Ftr[1,90] = 1.224, p = 0.2972; Fi[10,90] = 5.916, p < 0.0001; n = 11); (NA: Ft[10,90] = 36.27, p < 0.0001; Ftr[1,90] = 1.841, p = 0.208; Fi[10,90] = 8.686, p < 0.0001; n = 11). In the same way, amphetamine-evoked release of DA and NA were also impaired in the poly(I:C) group (DA: Ft[8,328] = 22.01, p < 0.0001; Ftr[1,328] = 4.507, p = 0.040; Fi[8,328] = 2.319, p = 0.020; n = 43); (NA: Ft[8,328] = 52.07; p < 0.0001; Ftr[1,328] = 4.322; p = 0.044; Fi[8,398] = 5.727; p < 0.0001; n = 43). This catecholamine imbalance was accompanied by increased dopamine D1 and D2 receptor expression (t = 2.64, p = 0.011 and t = 3.55, p = 0.0009; respectively), whereas tyrosine hydroxylase, DA and NA tissue content, DA and NA transporter (DAT/NET) expression and function were unaltered. CONCLUSIONS: MIA induces in offspring a presynaptic catecholaminergic hypofunction in PFC with cognitive impairment. This poly(I:C)-based model reproduces catecholamine phenotypes reported in schizophrenia and represents an opportunity for the study of cognitive impairment associated to this disorder.

Peripheral CB1 receptor blockade acts as a memory enhancer through a noradrenergic mechanism.

Peripheral inputs continuously shape brain function and can influence memory acquisition, but the underlying mechanisms have not been fully understood. Cannabinoid type-1 receptor (CB1R) is a well-recognized player in memory performance, and its systemic modulation significantly influences memory function. By assessing low arousal/non-emotional recognition memory in mice, we found a relevant role of peripheral CB1R in memory persistence. Indeed, the peripherally-restricted CB1R specific antagonist AM6545 showed significant mnemonic effects that were occluded in adrenalectomized mice, and after peripheral adrenergic blockade. AM6545 also transiently impaired contextual fear memory extinction. Vagus nerve chemogenetic inhibition reduced AM6545-induced mnemonic effect. Genetic CB1R deletion in dopamine ß-hydroxylase-expressing cells enhanced recognition memory persistence. These observations support a role of peripheral CB1R modulating adrenergic tone relevant for cognition. Furthermore, AM6545 acutely improved brain connectivity and enhanced extracellular hippocampal norepinephrine. In agreement, intra-hippocampal ß-adrenergic blockade prevented AM6545 mnemonic effects. Altogether, we disclose a novel CB1R-dependent peripheral mechanism with implications relevant for lengthening the duration of non-emotional memory.

Modulation of neurotransmitter release in orexin/hypocretin-2 receptor knockout mice: a microdialysis study.

Orexinergic neurons are discretely localized within the lateral hypothalamus and have widespread projections to the whole brain. Here, the role of orexin/hypocretin-2 receptors (OX2) in modulating extracellular concentrations of neurotransmitters was evaluated in the hypothalamus and the prefrontal cortex (PFC) of OX2 knockout (KO) mice by using a microdialysis technique. In the hypothalamus, basal concentrations of norephinephrine (NE), acetylcholine (ACh), and histamine (Hist) were significantly higher in KO mice, whereas KCl perfusion (147 mM) resulted in significantly lesser increases in NE, ACh, and Hist release in KO compared with wild-type (WT) mice. No differences in basal concentrations or evoked release of serotonin (5-HT) or dopamine (DA) were found in the hypothalamus between genotypes. In the PFC, no differences in the basal concentrations of the studied neurotransmitters were found between genotypes. After KCl perfusion, significantly higher increases in NE, 5-HT, and DA release were found in KO compared with WT mice. No differences in the evoked release of ACh and Hist in the PFC were found between genotypes. The present results demonstrate that genetic deletion of OX2 receptors differentially modulates extracellular concentrations of distinct neurotransmitters in the somatodendritic region vs. a nerve terminal region of the orexinergic neurons. In the hypothalamus, an inhibitory role of the OX2 receptors in modulating basal concentrations of NE, ACh, and Hist was revealed, which probably accounts for the reduced responsiveness to KCl as well. In the PFC, the evoked release of the monoamines NE, 5-HT, and DA seems to be controlled negatively by OX2 receptors.

Paliperidone Reversion of Maternal Immune Activation-Induced Changes on Brain Serotonin and Kynurenine Pathways.

Emerging evidence indicates that early-life exposure to environmental factors may increase the risk for schizophrenia via inflammatory mechanisms. Inflammation can alter the metabolism of tryptophan through the oxidative kynurenine pathway to compounds with neurotoxic and neuroprotective activity and compromise serotonin (5-HT) synthesis. Here we investigate the role of serotonergic and kynurenine pathways in the maternal immune activation (MIA) animal model of schizophrenia. The potential reversion exerted by long-term antipsychotic treatment was also evaluated. MIA was induced by prenatal administration of polyinosinic:polycytidylic acid (poly (I:C)) in mice. Expression of different proteins and the content of different metabolites involved in the function of serotonergic and kynurenine pathways was assessed by RT-PCR, immunoblot and ELISA analyses in frontal cortex of the offspring after puberty. MIA decreased tissue 5-HT content and promoted changes in the expression of serotonin transporter, 5-HT2A and 5-HT2C receptors. Expression of indoleamine 2,3-dioxygenase 2 (IDO2) and kynurenine 3-monooxygenase (KMO) was increased by poly (I:C) whereas kynurenine aminotransferase II and its metabolite kynurenic acid were not altered. Long-term paliperidone was able to counteract MIA-induced changes in 5-HT and KMO, and to increase tryptophan availability and tryptophan hydroxylase-2 expression in poly (I:C) mice but not in controls. MIA-induced increase of the cytotoxic risk ratio of kynurenine metabolites (quinolinic/kynurenic acid) was also reversed by paliperidone. MIA induces specific long-term brain effects on serotonergic activity. Such effects seem to be related with alternative activation of the kynurenine metabolic pathway towards a cytotoxic status. Atypical antipsychotic paliperodine partially remediates abnormalities observed after MIA.

Chronic fluoxetine reverses the effects of chronic corticosterone treatment on α2-adrenoceptors in the rat frontal cortex but not locus coeruleus.

Disruption of the hypothalamic-pituitary-adrenal axis is an established finding in patients with anxiety and/or depression. Chronic corticosterone administration in animals has been proposed as a model for the study of these stress-related disorders and the antidepressant action. Alterations of the central noradrenergic system and specifically of inhibitory α2-adrenoceptors seem to be part of the pathophysiology of depression and contribute to the antidepressant activity. The present study evaluates in male rats the effect of chronic corticosterone treatment during 35 days (16-20 mg kg-1 day-1) on the sensitivity of α2-adrenoceptors expressed in the somatodendritic and terminal noradrenergic areas locus coeruleus (LC) and prefrontal cortex (PFC), respectively. Further, the effect of chronic fluoxetine treatment (5 mg kg-1, i.p., since the 15th day) on the sensitivity of α2-adrenoceptors was examined under control conditions and in corticosterone-treated rats. The α2-adrenoceptor functionality was analysed in vitro by agonist-mediated [35S]GTPγS binding stimulation and in vivo through the modulation of noradrenaline (NA) release evaluated by dual-probe microdialysis. The concentration-effect curves of the [35S]GTPγS binding stimulation by the agonist UK14304 (5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)-6-quinoxalinamine) demonstrated a desensitization of cortical α2-adrenoceptors induced by corticosterone (-logEC50 = 6.7 ±â€¯0.2 vs 8.2 ±â€¯0.3 in controls) that was reverted by fluoxetine treatment (-logEC50 = 7.5 ±â€¯0.3). Local administration of the α2-adrenoceptor antagonist RS79948 ((8aR,12aS,13aS)-5,8,8a,9,10,11,12,12a,13,13a-decahydro-3-methoxy-12-(ethylsulfonyl)-6H-isoquino[2,1-g][1,6]naphthyridine) (0.1-100 µmol L-1) into the LC induced a concentration-dependent NA increase in the PFC of the control group (Emax = 191 ±â€¯30%) but non-significant effect was observed in corticosterone-treated rats (Emax = 133 ±â€¯46%), reflecting a desensitization of α2-adrenoceptors that control the firing of noradrenergic neurons. Fluoxetine treatment did not alter the corticosterone-induced desensitization in this area (Emax = 136 ±â€¯19%). No effect of fluoxetine on α2-adrenoceptor functionality was observed in control animals (Emax = 223 ±â€¯30%). In PFC, the local administration of RS79948 increased NA in controls (Emax = 226 ±â€¯27%) without effect in the corticosterone group (Emax = 115 ±â€¯26%), suggesting a corticosterone-induced desensitization of terminal α2-adrenoceptors. Fluoxetine administration prevented the desensitization induced by corticosterone in the PFC (Emax = 233 ±â€¯33%) whereas desensitized α2-adrenoceptors in control animals (Emax = -24 ±â€¯10%). These data indicate that chronic corticosterone increases noradrenergic activity by acting at different α2-adrenoceptor subpopulations. Treatment with the antidepressant fluoxetine seems to counteract these changes by acting mainly on presynaptic α2-adrenoceptors expressed in terminal areas.

Selective Knockdown of TASK3 Potassium Channel in Monoamine Neurons: a New Therapeutic Approach for Depression.

Current pharmacological treatments for major depressive disorder (MDD) are severely compromised by both slow action and limited efficacy. RNAi strategies have been used to evoke antidepressant-like effects faster than classical drugs. Using small interfering RNA (siRNA), we herein show that TASK3 potassium channel knockdown in monoamine neurons induces antidepressant-like responses in mice. TASK3-siRNAs were conjugated to cell-specific ligands, sertraline (Ser) or reboxetine (Reb), to promote their selective accumulation in serotonin (5-HT) and norepinephrine (NE) neurons, respectively, after intranasal delivery. Following neuronal internalization of conjugated TASK3-siRNAs, reduced TASK3 mRNA and protein levels were found in the brainstem 5-HT and NE cell groups. Moreover, Ser-TASK3-siRNA induced robust antidepressant-like behaviors, enhanced the hippocampal plasticity, and potentiated the fluoxetine-induced increase on extracellular 5-HT. Similar responses, yet of lower magnitude, were detected for Reb-TASK3-siRNA. These findings provide substantial support for TASK3 as a potential target, and RNAi-based strategies as a novel therapeutic approach to treat MDD.

Guanidine and 2-aminoimidazoline aromatic derivatives as alpha2-adrenoceptor antagonists. 2. Exploring alkyl linkers for new antidepressants.

The preparation of a number of (bis)guanidine and (bis)2-aminoimidazoline derivatives as potential alpha 2-adrenoceptor antagonists for the treatment of depression is presented. Human brain tissue was used to measure their affinity toward the alpha 2-adrenoceptors in vitro. Compounds 6b, 8b, 9b, 10b, 15b, 17b, 18b, 20b, and 21b displayed a good affinity (pKi > 7) and were evaluated in in vitro functional [(35)S]GTPgammaS binding assays in human prefrontal cortex to determine their agonistic or antagonistic activity. Among these compounds, 17b and 20b showed the expected behavior for an antagonist and were subject to in vivo microdialysis experiments in rats. Significantly, these experiments confirmed the antagonistic properties of 17b and 20b, and therefore both compounds can be considered as potential antidepressants.

Serotonin 5-HT3 receptor antagonism potentiates the antidepressant activity of citalopram.

Activation of serotonin 5-HT3 receptor (5HT3R) in the locus coeruleus (LC), the principal somatodendritic noradrenergic area, decreases LC firing activity and noradrenaline (NA) release in prefrontal cortex (PFC). Blockade of 5HT3R in coadministration with selective serotonin reuptake inhibitors (SSRIs) has been proposed as a potential strategy to accelerate the onset of action of SSRIs. Dual-probe microdialysis in rats was used to evaluate the involvement of 5HT3R in the in vivo effect exerted by the SSRI citalopram on NA release. Besides, forced swimming test (FST) was carried out in mice to evaluate the antidepressant-like effect of citalopram in combination with a 5HT3R antagonist (Y25130). Systemic administration of the 5HT3R agonist SR57227 (10 mg/kg i.p.) increased NA in LC (Emax = 200 ±â€¯27%) and PFC (Emax = 133 ±â€¯2%). The increase in PFC was enhanced in local presence into LC of Y25130 (50 µM) (Emax = 296 ±â€¯41%) suggesting an inhibitory function on NA release exerted by the activation of 5HT3R located in somatodendritic areas. Citalopram administration (10 mg/kg i.p.) increased NA in LC (Emax = 185 ±â€¯11%) and decreased it in PFC (Emax = -35 ±â€¯7%). Intra-LC (50 µM) or systemic co-administration of Y25130 (10 mg/kg i.p.) with citalopram (10 mg/kg i.p.) switched NA release in the PFC from an inhibition to a stimulatory effect. In mice FST, systemic coadministration of citalopram (2.5 mg/kg i.p.) and Y25130 (10 mg/kg i.p.) potentiated the decrease of immobility time through the increase of both swimming and climbing behaviours. These results suggest that the addition of a 5HT3R antagonist to SSRIs could represent a feasible strategy to improve antidepressant response.

Structural and Functional Characterization of the Interaction of Snapin with the Dopamine Transporter: Differential Modulation of Psychostimulant Actions.

The importance of dopamine (DA) neurotransmission is emphasized by its direct implication in several neurological and psychiatric disorders. The DA transporter (DAT), target of psychostimulant drugs, is the key protein that regulates spatial and temporal activity of DA in the synaptic cleft via the rapid reuptake of DA into the presynaptic terminal. There is strong evidence suggesting that DAT-interacting proteins may have a role in its function and regulation. Performing a two-hybrid screening, we identified snapin, a SNARE-associated protein implicated in synaptic transmission, as a new binding partner of the carboxyl terminal of DAT. Our data show that snapin is a direct partner and regulator of DAT. First, we determined the domains required for this interaction in both proteins and characterized the DAT-snapin interface by generating a 3D model. Using different approaches, we demonstrated that (i) snapin is expressed in vivo in dopaminergic neurons along with DAT; (ii) both proteins colocalize in cultured cells and brain and, (iii) DAT and snapin are present in the same protein complex. Moreover, by functional studies we showed that snapin produces a significant decrease in DAT uptake activity. Finally, snapin downregulation in mice produces an increase in DAT levels and transport activity, hence increasing DA concentration and locomotor response to amphetamine. In conclusion, snapin/DAT interaction represents a direct link between exocytotic and reuptake mechanisms and is a potential target for DA transmission modulation.

Guanidine and 2-aminoimidazoline aromatic derivatives as alpha(2)-adrenoceptor antagonists, 1: toward new antidepressants with heteroatomic linkers.

The efficient preparation and pharmacological characterization of different families of (bis)guanidine and (bis)2-aminoimidazoline derivatives ("twin" and "half" molecules) as potential alpha(2)-adrenoceptor antagonists for the treatment of depression is presented. The affinity toward the alpha(2)-adrenoceptor of all the compounds prepared was measured in vitro in human brain tissue. Additionally, the activity as agonist or antagonist of those compounds with a pK(i) larger than 7 was determined in functional [(35)S]GTPgammaS binding assays in human brain tissue. Finally, the activity of the most promising compounds was confirmed by means of in vivo microdialysis experiments in rats. Compounds 1, 2b, 3b, 12b, 13b, 17b, 18b, 22b, 25b, 26b, 28b, and 30 showed a good affinity toward the alpha(2)-ARs. In general, the 2-aminoimidazoline derivatives displayed higher affinities than their guanidine analogues. Finally and most importantly, compounds 18b and 26b showed antagonistic properties over alpha(2)-ARs not only in vitro [(35)S]GTPgammaS binding but also in vivo microdialysis experiments. Moreover, both compounds have shown to be able to cross the blood-brain barrier and, therefore, they can be considered as potential antidepressants.

Chronic citalopram administration desensitizes prefrontal cortex but not somatodendritic α2-adrenoceptors in rat brain.

Selective serotonin reuptake inhibitors (SSRIs) regulate brain noradrenergic neurotransmission both at somatodendritic and nerve terminal areas. Previous studies have demonstrated that noradrenaline (NA) reuptake inhibitors are able to desensitize α2-adrenoceptor-mediated responses. The present study was undertaken to elucidate the effects of repeated treatment with the SSRI citalopram on the α2-adrenoceptor sensitivity in locus coeruleus (LC) and prefrontal cortex (PFC), by using in vivo microdialysis and electrophysiological techniques, and in vitro stimulation of [35S]GTPγS binding autoradiography. Repeated, but not acute, treatment with citalopram (5 mg/kg, i.p., 14 days) increased extracellular NA concentration selectively in PFC. The α2-adrenoceptor agonist clonidine (0.3 mg/kg, i.p.), administered to saline-treated animals (1 ml/kg i.p., 14 days) induced NA decrease in LC (Emax = -44 ± 4%; p < 0.001) and in PFC (Emax = -61 ± 5%, p < 0.001). In citalopram chronically-treated rats, clonidine administration exerted a lower decrease of NA (Emax = -25 ± 7%; p < 0.001) in PFC whereas the effect in LC was not different to controls (Emax = -36 ± 4%). Clonidine administration (0.625-20 µg/kg, i.v.) evoked a dose-dependent decrease of the firing activity of LC noradrenergic neurons in both citalopram- (ED50 = 3.2 ± 0.4 µg/kg) and saline-treated groups (ED50 = 2.6 ± 0.5 µg/kg). No significant differences between groups were found in ED50 values. The α2-adrenoceptor agonist UK14304 stimulated specific [35S]GTPγS binding in brain sections containing LC (144 ± 14%) and PFC (194 ± 32%) of saline-treated animals. In citalopram-treated animals, this increase did not differ from controls in LC (146 ± 22%) but was lower in PFC (141 ± 8%; p < 0.05). Taken together, long-term citalopram treatment induces a desensitization of α2-adrenoceptors acting as axon terminal autoreceptors in PFC without changes in somatodendritic α2-adrenoceptor sensitivity.

Effect of subchronic corticosterone administration on α2-adrenoceptor functionality in rat brain: an in vivo and in vitro study.

RATIONALE: Noradrenergic system plays a critical role in the hypothalamic-pituitary-adrenal (HPA) axis regulation and the stress response. A dysregulated HPA axis may be indicative of an increased biological vulnerability for depression. In addition, a variety of studies have focused on specific alterations of α2-adrenoceptors as a mechanism involved in the pathogenesis of mood disorders and antidepressant response. OBJECTIVES: This study aimed to evaluate the effect of subchronic corticosterone administration on rat brain α2-adrenoceptor functionality by in vitro [35S]GTPγS binding stimulation assays and in vivo dual-probe microdialysis determination of extracellular noradrenaline concentrations. RESULTS: Implantation of a time release corticosterone pellet during 14 days induced sustained changes in endocrine function. However, there were no differences in α2-adrenoceptor agonist UK14304-induced stimulation of [35S]GTPγS binding in prefrontal cortex (PFC) between corticosterone-treated and control rats. In the same way, the in vivo evaluation of α2-adrenoceptor-mediated noradrenaline release responses to the α2-adrenoceptor agonist clonidine local administration into the locus coeruleus (LC), and the PFC did not show differences between the groups. CONCLUSIONS: The present results show that subchronic corticosterone administration does not induce changes on functionality of α2-adrenoceptors neither in the LC nor in noradrenergic cortical terminal areas.

Alterations in neutrophil extracellular traps is associated with the degree of decompensation of liver cirrhosis.

INTRODUCTION: Liver cirrhosis (LC) constitutes one of the main 10 causes of death worldwide. LC has a characteristic asymptomatic compensated phase followed by a progressive decompensated phase, in which diverse complications are presented. LC patients are highly prone to bacterial infections. The neutrophils in these patients present defects in the production of oxygen radicals, which are essential for bacteria elimination as in the activation of neutrophil extracellular traps (NETs). The main objective of this work was to determine the NETs and neutrophil activation markers in LC patients. METHODOLOGY: Neutrophil purification was done with Ficoll Histopaque from a sample of the peripheral blood of patients with compensated and decompensated LC. Neutrophils were activated with Phorbol 12-myristate 13-acetate to evaluate the release of NETs by means of fluorescence microscopy and fluorometry, while expression of activation markers (CD69, CD80, perforin, and CAP-18) was evaluated by flow cytometry. RESULTS: A significant decrease in the release capability of NETs was observed as the level of LC in the patient increased. When comparing serum levels in inflammatory cytokines among the different study groups, significant differences were observed. No significant differences were detected on neutrophil activation markers; nevertheless, there was a correlation between diminution of CD69 and CD80 expression in decompensated patients. CONCLUSIONS: We demonstrated that LC patients with neutrophil extracellular trap release deficiencies could have an increased rate of complications.

The role of FABP2 gene polymorphism in alcoholic cirrhosis.

Hypertriglyceridemia and dietary lipids have been suggested to modulate the severity of alcoholic liver disease and the progression to alcoholic cirrhosis (AC). The intestinal fatty acid binding protein (IFABP) is the main transporter of dietary fatty acids into the enterocyte and has a genetic polymorphism, FABP2 A54T that has been associated with hypertriglyceridemia. We determined the frequency of the FABP2 gene polymorphism using PCR-RFLP and measured serum triglycerides, HDL, LDL, total lipids and cholesterol in 67 patients with AC and in 124 unrelated healthy individuals. Frequencies of genotypes and alleles were similar between the two groups. The healthy subjects, who were homozygous for the Thr54 genotype had significantly higher mean triglyceride serum concentrations than those homozygous for the Ala54 genotype (P<0.05). However, AC patients who were homozygous for the Thr54 genotype, had lower mean triglyceride serum concentrations (P<0.01), and had a significantly longer period of continued alcohol abuse prior to the diagnosis of liver cirrhosis compared to the AC patients homozygous for the Ala54 genotype (P<0.05). Our data suggests that the polymorphism Thr54 of the FABP2 gene is associated with a later onset of AC in the lower economic status Mexican population studied.

α2-adrenoceptor antagonists: synthesis, pharmacological evaluation, and molecular modeling investigation of pyridinoguanidine, pyridino-2-aminoimidazoline and their derivatives.

We have previously identified phenylguanidine and phenyl-2-aminoimidazoline compounds as high affinity ligands with conflicting functional activity at the α2-adrenoceptor, a G-protein-coupled receptor with relevance in several neuropsychiatric conditions. In this paper we describe the design, synthesis, and pharmacological evaluation of a new series of pyridine derivatives [para substituted 2- and 3-guanidino and 2- and 3-(2-aminoimidazolino)pyridines, disubstituted 2-guanidinopyridines and N-substituted-2-amino-1,4-dihydroquinazolines] that were found to be antagonists/inverse agonists of the α2-adrenoceptor. Furthermore, the compounds exert their effects at the α2-adrenoceptor both in vitro in human prefrontal cortex tissue and in vivo in rat brain as shown by microdialysis experiments. We also provide a docking study at the α2A- and α2C-adrenoceptor subtypes demonstrating the structural features required for high affinity binding to the receptor.

Vitronectin expression in the airways of subjects with asthma and chronic obstructive pulmonary disease.

Vitronectin, a multifunctional glycoprotein, is involved in coagulation, inhibition of the formation of the membrane attack complex (MAC), cell adhesion and migration, wound healing, and tissue remodeling. The primary cellular source of vitronectin is hepatocytes; it is not known whether resident cells of airways produce vitronectin, even though the glycoprotein has been found in exhaled breath condensate and bronchoalveolar lavage from healthy subjects and patients with interstitial lung disease. It is also not known whether vitronectin expression is altered in subjects with asthma and COPD. In this study, bronchial tissue from 7 asthmatic, 10 COPD and 14 control subjects was obtained at autopsy and analyzed by immunohistochemistry to determine the percent area of submucosal glands occupied by vitronectin. In a separate set of experiments, quantitative colocalization analysis was performed on tracheobronchial tissue sections obtained from donor lungs (6 asthmatics, 4 COPD and 7 controls). Vitronectin RNA and protein expressions in bronchial surface epithelium were examined in 12 subjects who undertook diagnostic bronchoscopy. Vitronectin was found in the tracheobronchial epithelium from asthmatic, COPD, and control subjects, although its expression was significantly lower in the asthmatic group. Colocalization analysis of 3D confocal images indicates that vitronectin is expressed in the glandular serous epithelial cells and in respiratory surface epithelial cells other than goblet cells. Expression of the 65-kDa vitronectin isoform was lower in bronchial surface epithelium from the diseased subjects. The cause for the decreased vitronectin expression in asthma is not clear, however, the reduced concentration of vitronectin in the epithelial/submucosal layer of airways may be linked to airway remodeling.

Paragonimiasis: a view from Columbia.

Paragonimiasis is a zoonosis caused by adult trematodes of the Paragonimus genus. The infection in humans is a result of a complex transmission cycle that includes two obligate intermediate hosts, a snail and a crustacean or a crayfish, and a definitive mammalian host. It has been shown that 9 of the more than 40 species of Paragonimus described affect humans in over 39 countries in Asia, Africa and America. It is estimated that 20.7 million people have paragonimiasis and it is calculated that 195 million people are at risk of being infected. The illness usually is caused once the parasite has settled in the lung at the site of the main clinical symptoms: cough, thoracic pain and hemoptysis. The diagnosis of paragonimiasis is based on the patient's history, the parasitological findings (ova in sputum and in feces), and the result of radiological and immunological tests. In severe cases, the patient may suffer from life-threatening hemoptysis or pneumothorax. Currently, praziquantel is the drug of choice.

Over-expression of TLR4-CD14, pro-inflammatory cytokines, metabolic markers and NEFAs in obese non-diabetic Mexicans.

INTRODUCTION: Obesity is the world's most important public health problem. Adipose tissue contributes significantly to increase pro-inflammatory mediators whose cascade begins with the union of TLR4 to its microbial ligands (TLR: Toll Like Receptors). It has been reported recently that NEFAs (Non-Esterified Fatty Acids) bind to this receptor as agonists. The purpose of our study was to determine the levels of expression of TLR4-CD14, the pro-inflammatory cytokines, the metabolic markers and the NEFAs in a group of adult, non-diabetic obese Mexicans. METHOD: A group of 210 adult middle-class Mexican non-diabetic obese patients was evaluated: 105 normal weight individuals, and 105 non-diabetic obese. On both groups, the following was tested in each patient: TLR4-CD14 receptors on monocytes in peripheral blood, inflammatory profile, HOMA-IR (Homeostasis Model Assessment-Insulin Resistance), NEFAs and each individual's anthropometric profile. RESULTS: Obesity is strongly associated with the expression of TLR4 (77%, MFI (Mean Fluorescence Index) 7.70) and CD14 (86% MFI 1.61) with 66% double positives (p = 0.000). These figures contrast with those for the normal weight individuals that constituted the control group: TLR4 (70% MFI 6.41) and CD14 (84% MFI 1.25) with 59% double positives. As for cytokine concentration, non- diabetic obese individuals vs the normal weight/thin, the numbers were: IL-1ß = 2.0 vs 2.5 pg/ml (p = NS), IL-6 = 36 vs 28 pg/ml (p = 0.030), IL-8 = 27 vs 27 pg/ml (p = NS), IL-10 = 8.4 vs 6.8 pg/ml (p = NS), TNF-α =31 vs 15 pg/ml (p = 0.000) respectively. Insulin levels were 12.1 vs 19.7 mcU/ml (p = 0.000) and the NEFAs were much higher in the obese vs normal weight/thin individuals (p = 0.000). CONCLUSION: Adipose tissue used to be thought of as mere storage of fats and energy, but it has been revealed to be an important neuro-immune-endocrine organ. Immune cells, stimulated by NEFAs, produce pro-inflammatory cytokines, which have a direct effect on oxidating radicals that directly target the release of noradrenalin. This in turn, reactivates the vicious cycle of low-grade chronic inflammation, as is now described in obesity.

Involvement of serotonin 5-HT3 receptors in the modulation of noradrenergic transmission by serotonin reuptake inhibitors: a microdialysis study in rat brain.

RATIONALE: Selective serotonin reuptake inhibitors (SSRIs), in addition to being able to enhance serotonergic neurotransmission, are able to modulate other brain systems involved in depression. OBJECTIVES: This study evaluates the neurochemical effect of the SSRI citalopram on brain noradrenergic activity and the serotonin receptor involved in this effect. METHODS: Dual-probe microdialysis in the locus coeruleus (LC) and prefrontal cortex (PFC) was performed in freely awake rats. RESULTS: Systemic citalopram (10 mg/kg, i.p.) increased noradrenaline (NA) in the LC (E max = 141 ± 13%) and simultaneously decreased NA in the PFC (Emax = -46 ± 7%). In the local presence into the LC of the α2-adrenoceptor antagonist RS79948 (1 µM), systemic citalopram increased NA in the LC (Emax = 157 ± 25%) and PFC (Emax = 175 ± 24%). Local citalopram (0.1-100 µM) into the LC induced NA increase in the LC (Emax = 210 ± 25%) and decrease in the PFC (Emax = -38 ± 9%). Local LC citalopram effect was abolished by LC presence of the 5-HT3 receptor antagonist MDL72222 (1 µM) but not the 5-HT1/2 receptor antagonist methiothepin (1 µM). Systemic citalopram in the LC presence of MDL72222 did not modify NA in the LC but increased NA in the PFC (Emax = 158 ± 26%). Local citalopram into the PFC enhanced NA (Emax = 376 ± 18%) in the area, which was prevented by MDL72222. CONCLUSIONS: The SSRI citalopram modulates central noradrenergic neurotransmission by activation, through endogenous serotonin, of 5-HT3 receptors expressed in the somatodendritic (LC) and terminal (PFC) areas, which subsequently promote an enhancement of local NA. Therefore, 5-HT3 receptors and somatodendritic α2-adrenoceptors in the LC play an important role in the global effect of SSRIs.