Measurement of the interaction between mucin and oenological tannins by Surface Plasmon Resonance (SPR); relationship with astringency.

The interaction between stomach porcine mucin and 3 oenological tannins (extract of ellagitannins from oak, extract of gallotannins from gall nuts and extract of proanthocyanidins from grape seeds) was measured by Surface Plasmon Resonance (SPR). These tannins were analysed and their astringency was determined using the Astringency Index method and by tasting. The interaction constants were determined using a Biacore SPR device (1:1 Langmuir binding model). The results indicate that the ellagitannins are more astringent than gallotannins and those, in turn, are more astringent than seed proanthocyanidins if the richness of the commercial extracts is considered. The astringency index of these tannins had high correlation and regression coefficients with their kinetic and thermodynamic dissociation constants. This data support a hypothesis that astringency depends not only on the thermodynamic tendency to form the complex between tannins and salivary proteins but also probably on the time required to dissociate the complex.

Spontaneously Arising Canine Glioma as a Potential Model for Human Glioma.

Human gliomas are malignant brain tumours that carry a poor prognosis and are composed of a heterogeneous population of cells. There is a paucity of animal models available for study of these tumours and most have been created by genetic modification. Spontaneously arising canine gliomas may provide a model for the characterization of the human tumours. The present study shows that canine gliomas form a range of immunohistochemical patterns that are similar to those described for human gliomas. The in-vitro sphere assay was used to analyze the expansion and differentiation potential of glioma cells taken from the periphery and centre of canine tumours. Samples from the subventricular zone (SVZ) and contralateral parenchyma were used as positive and negative controls, respectively. The expansion potential for all of these samples was low and cells from only three cultures were expanded for six passages. These three cultures were derived from high-grade gliomas and the cells had been cryopreserved. Most of the cells obtained from the centre of the tumours formed spheres and were expanded, in contrast to samples taken from the periphery of the tumours. Spheres were also formed and expanded from two areas of apparently unaffected brain parenchyma. The neurogenic SVZ contralateral samples also contained progenitor proliferating cells, since all of them were expanded for three to five passages. Differentiation analysis showed that all cultured spheres were multipotential and able to differentiate towards both neurons and glial cells. Spontaneously arising canine gliomas might therefore constitute an animal model for further characterization of these tumours.

Effect of two different treatments for reducing grape yield in Vitis vinifera cv Syrah on wine composition and quality: berry thinning versus cluster thinning.

The influence of two treatments for reducing grape yield, cluster thinning and berry thinning, on red wine composition and quality were studied in a Vitis vinifera cv Syrah vineyard in AOC Penedès (Spain). Cluster thinning reduced grape yield per vine by around 40% whereas berry thinning only reduced it by around 20%. Cluster thinning grapes had higher soluble solids content than control grapes, and their resultant wines have greater anthocyanin and polysaccharide concentrations than the control wine. Wine obtained from berry thinning grapes had a higher total phenolic index, greater flavonol, proanthocyanidin, and polysaccharide concentrations, and lower titratable acidity than the control wine. Wines obtained from both treatments were sufficiently different from the control wine to be significantly distinguished by a trained panel in a triangular test. Even though both treatments seem to be effective at improving the quality of wine, berry thinning has the advantage because it has less impact on crop yield reduction.

Arsenic and fluoride induce neural progenitor cell apoptosis.

The aim of the present study is to determine the effect of inorganic arsenic (As) and its metabolites on the viability of the neural progenitor cell (NPC) line C17.2, in order to evaluate cellular mechanisms involved in As developmental neurotoxicity. Moreover, we analyzed the effects of the coexposure to As and fluoride (F), a situation to which some populations are commonly exposed. Our results show that NPCs are not susceptible to pentavalent As species [arsenate, monomethylarsonic acid, and dimethylarsinic acid] and F alone. However, the trivalent metabolites of arsenate [arsenite, monomethylarsonous acid, and dimethylarsinous acid] are toxic at concentrations below 1 mg/l, and this susceptibility increases when there is coexposure with F (≥ 5 mg/l). Arsenite triggers apoptosis after 24 h of exposure, whereas monomethylarsonous acid produces necrosis at very short times (2 h). Arsenite leads to an increase in intracellular Ca levels and generation of reactive oxygen species, which may cause a decrease in mitochondrial transmembrane potential, release of cytochrome c, and consequent activation of caspases. A slight activation of calpain also takes place, which might favor activation of the mitochondrial pathway or might activate other pathways. The treatment with some antioxidants such as quercetin and α-tocopherol shows only a partial reduction of the cytotoxicity.

Smell training increases cognitive smell skills of wine tasters compared to the general healthy population. The WINECAT Study.

BACKGROUND: Wine experts show higher accuracy than novices in selecting a wine that matches a sample. Only one study has compared wine experts with non-trained healthy controls on smell. The aim of this study was to compare the smell characteristics, both sensorial and cognitive, of wine tasters with Spanish healthy population using the Barcelona Smell Test-24. METHODS: Wine tasters were tested for smell and compared with a control group of healthy volunteers, by tasting 20 odours and scoring smell detection, identification, intensity, irritability, freshness, pleasure and forced choice. RESULTS: Wine tasters performed significantly better on identification and forced choice than healthy controls. In addition, wine tasters perceived more odours as intense, but fewer as irritating than controls. CONCLUSIONS: Probably linked to smell education, wine tasters show better cognitive but not sensorial smell skills than a non-trained healthy population.

BDNF regulation under GFAP promoter provides engineered astrocytes as a new approach for long-term protection in Huntington's disease.

Brain-derived neurotrophic factor (BDNF) is the main candidate for neuroprotective therapeutic strategies for Huntington's disease. However, the administration system and the control over the dosage are still important problems to be solved. Here we generated transgenic mice overexpressing BDNF under the promoter of the glial fibrillary acidic protein (GFAP) (pGFAP-BDNF mice). These mice are viable and have a normal phenotype. However, intrastriatal administration of quinolinate increased the number of reactive astrocytes and enhanced the release of BDNF in pGFAP-BDNF mice compared with wild-type mice. Coincidentally, pGFAP-BDNF mice are more resistant to quinolinate than wild-type mice, suggesting a protective effect of astrocyte-derived BDNF. To verify this, we next cultured astrocytes from pGFAP-BDNF and wild-type mice for grafting. Wild-type and pGFAP-BDNF-derived astrocytes behave similarly in nonlesioned mice. However, pGFAP-BDNF-derived astrocytes showed higher levels of BDNF and larger neuroprotective effects than the wild-type ones when quinolinate was injected 30 days after grafting. Interestingly, mice grafted with pGFAP-BDNF astrocytes showed important and sustained behavioral improvements over time after quinolinate administration as compared with mice grafted with wild-type astrocytes. These findings show that astrocytes engineered to release BDNF can constitute a therapeutic approach for Huntington's disease.

PH domain leucine-rich repeat protein phosphatase 1 contributes to maintain the activation of the PI3K/Akt pro-survival pathway in Huntington's disease striatum.

Dysregulation of gene expression is one of the mechanisms involved in the pathophysiology of Huntington's disease (HD). Here, we examined whether mutant huntingtin regulates the levels of PH domain leucine-rich repeat protein phosphatase 1 (PHLPP1), a phosphatase that specifically dephosphorylates Akt at Ser473. Our results show decreased PHLPP1 protein levels in knock-in models (Hdh(Q111/Q111) mouse striatum and STHdh(Q111/Q111) cells), in the striatum of N-terminal exon-1 mutant huntingtin transgenic mouse models (R6/1; R6/1 : BDNF + or - , R6/2 and Tet/HD94) and in the putamen of HD patients. Quantitative PCR analysis revealed a reduction in PHLPP1 mRNA levels in the striatum of R6/1 compared with wild-type mice. Coincident with reduced PHLPP1 protein levels, we observed increased phosphorylated Akt (Ser473) levels specifically in the striatum. The analysis of the conditional mouse model Tet/HD94 disclosed that after mutant huntingtin shutdown PHLPP1 levels returned to wild-type levels whereas phospho-Akt levels were partially reduced. In conclusion, our results show that mutant huntingtin downregulates PHLPP1 expression. In the striatum, these reduced levels of PHLPP1 can contribute to maintain high levels of activated Akt that may delay cell death and allow the recovery of neuronal viability after mutant huntingtin silencing.

Brain-derived neurotrophic factor modulates the severity of cognitive alterations induced by mutant huntingtin: involvement of phospholipaseCgamma activity and glutamate receptor expression.

The involvement of brain-derived neurotrophic factor (BDNF) in cognitive processes and the decrease in its expression in Huntington's disease suggest that this neurotrophin may play a role in learning impairment during the disease progression. We therefore analyzed the onset and severity of cognitive deficits in two different mouse models with the same mutant huntingtin but with different levels of BDNF (R6/1 and R6/1:BDNF+/- mice). We observed that BDNF modulates cognitive function in different learning tasks, even before the onset of motor symptoms. R6/1:BDNF+/- mice showed earlier and more accentuated cognitive impairment than R6/1 mice at 5 weeks of age in discrimination learning; at 5 weeks of age in procedural learning; and at 9 weeks of age in alternation learning. At the earliest age at which cognitive impairment was detected, electrophysiological analysis was performed in the hippocampus. All mutant genotypes showed reduced hippocampal long term potentiation (LTP) with respect to wild type but did not show differences between them. Thus, we evaluated the involvement of BDNF-trkB signaling and glutamate receptor expression in the hippocampus of these mice. We observed a decrease in phospholipaseCgamma activity, but not ERK, in R61, BDNF+/- and R6/1:BDNF+/- hippocampus at the age when LTP was altered. However, a specific decrease in the expression of glutamate receptors NR1, NR2A and GluR1 was detected only in R6/1:BDNF+/- hippocampus. Therefore, these results show that BDNF modulates the learning and memory alterations induced by mutant huntingtin. This interaction leads to intracellular changes, such as specific changes in glutamate receptors and in BDNF-trkB signaling through phospholipaseCgamma.

Novel cryopreservation method for dissociated human embryonic stem cells in the presence of a ROCK inhibitor.

BACKGROUND: Human embryonic stem cells (hESCs) have potential use in clinical therapy and regenerative medicine. One of the major challenges regarding the application of these cells is the development of an efficient cryopreservation protocol, since current methods, which include slow-freezing-rapid thawing and vitrification of colonies in suspension, present poor viability and high differentiation rates. Dissociated hESC suspensions do not survive cryopreservation because they are susceptible to apoptosis upon cell detachment and dissociation. A selective Rho-associated kinase (ROCK) inhibitor has been reported to increase the survival of dissociated hESCs and their cloning efficiency. METHODS AND RESULTS: Here, we describe a novel method for dissociated hESCs cryopreservation in the presence of the ROCK inhibitor Y-27632. The addition of this inhibitor to the freezing and post-thawing medium significantly increased the survival rate and efficiency of colony formation. Moreover, the hESC colonies obtained after the cryopreservation in the presence of the ROCK inhibitor showed a very low rate of differentiation and a reduced time of recovery. After prolonged culture of frozen-thawed dissociated hESCs, the characteristic properties of pluripotent cells were observed, including normal karyotype, morphological features, marker expression (SSEA-4, TRA-1-60, TRA-1-81 and Oct-4) and the potential to differentiate into derivatives of all three germ layers after embryoid bodies formation. CONCLUSION: This novel method for the cryopreservation of dissociated hESCs may reduce the time required to amplify frozen stocks, and facilitate not only the storage of large numbers of hESCs but also the widespread use of these cells in regenerative medicine.

Neuroprotection by GDNF-secreting stem cells in a Huntington's disease model: optical neuroimage tracking of brain-grafted cells.

The use of stem cells for reconstructive or neuroprotective strategies can benefit from new advances in neuroimaging techniques to track grafted cells. In the present work, we analyze the potential of a neural stem cell (NSC) line, which stably expresses the glial cell line-derived neurotrophic factor (GDNF) and the firefly luciferase gene (GDNF/Luc-NSC), for cell therapy in a Huntington's disease mouse model. Our results show that detection of light photons is an effective method to quantify the proliferation rate and to characterize the migration pathways of transplanted NSCs. Intravenous administration of luciferine, the luciferase substract, into the grafted animals allowed the detection of implanted cells in real time by an optical neuroimaging methodology, overpassing the limits of serial histological analyses. We observed that transplanted GDNF/Luc-NSCs survive after grafting and expand more when transplanted in quinolinate-lesioned nude mouse striata than when transplanted in non-lesioned mice. We also demonstrate that GDNF/Luc-NSCs prevent the degeneration of striatal neurons in the excitotoxic mouse model of Huntington's disease and reduce the amphetamine-induced rotational behavior in mice bearing unilateral lesions.

Mice heterozygous for neurotrophin-3 display enhanced vulnerability to excitotoxicity in the striatum through increased expression of N-methyl-D-aspartate receptors.

The striatum is one of the brain areas most vulnerable to excitotoxicity, a lesion that can be prevented by neurotrophins. In the present study, intrastriatal injection of the N-methyl-d-aspartate receptor (NMDAR) agonist quinolinate (QUIN) was performed in mice heterozygous for neurotrophin-3 (NT3 +/-) or brain-derived neurotrophic factor (BDNF +/-) to analyze the role of endogenous neurotrophins on the regulation of striatal neurons susceptibility to excitotoxic injury. QUIN injection induced a decrease in dopamine- and cyclic AMP-regulated phosphoprotein of 32 kDa (DARPP-32) protein levels that was higher in NT-3 +/- than in BDNF+/- or wild type animals. This enhanced susceptibility was specific for enkephalin- and tachykinin-positive projection neurons, and also for parvalbumin-positive interneurons. However the excitotoxic damage in large interneurons was not modified in NT-3 +/- mice compared with wild type animals. This effect can be related to the regulation of NMDARs by endogenous NT-3. Thus, our results show that there is an age-dependent regulation of NMDAR subunits NR1 and NR2A, but not NR2B, in NT-3 +/- mice. The deficit of endogenous NT-3 induced a decrease in NR1 and NR2A subunits at postnatal day (P) 0 and P3 mice respectively, whereas an upregulation was observed in 12 week old NT-3 +/- mice. This differential effect was also observed after administration of exogenous NT-3. In primary striatal cultures, NT-3 treatment induced an enhancement in NR2A, but not NR2B, protein levels. However, intrastriatal grafting of NT-3 secreting-cells in adult wild type mice produced a down-regulation of NR2A subunit. In conclusion, NT-3 regulates the expression of NMDAR subunits modifying striatal neuronal properties that confers the differential vulnerability to excitotoxicity in projection neurons and interneurons in the striatum.

In vivo evaluation of EPO-secreting cells immobilized in different alginate-PLL microcapsules.

Alginates are the most employed biomaterials for cell encapsulation due to their abundance, easy gelling properties and apparent biocompatibility. However, as natural polymers different impurities including endotoxins, proteins and polyphenols can be found in their composition. Several purification protocols as well as different batteries of assays to prove the biocompatibility of the alginates in vitro have been recently developed. However, little is known about how the use of alginates with different purity grade may affect the host immune response after their implantation in vivo. The present paper investigates the long-term functionality and biocompatibility of murine erythropoietin (EPO) secreting C2C12 cells entrapped in microcapsules elaborated with alginates with different properties (purity, composition and viscosity). Results showed that independently of the alginate type employed, the animals presented elevated hematocrit levels until day 130, remaining at values between 70-87%. However, histological analysis of the explanted devices showed higher overgrowth around non-biomedical grade alginate microcapsules which could be directly related with higher impurity content of this type of alginate. Although EPO delivery may be limited by the formation of a fibrotic layer around non-biomedical grade alginate microcapsules, the high EPO secretion of the encapsulated cells together with the pharmacodynamic behaviour and the angiogenic and immune-modulatory properties of EPO result in no direct correlation between the biocompatibility of the alginate and the therapeutic response obtained.

Cellular and molecular mechanisms involved in the selective vulnerability of striatal projection neurons in Huntington's disease.

Neurodegenerative disorders affecting the central nervous system, such as Alzheimer's disease, Parkinson's disease, Huntington's chorea (HD) and amyotrophic lateral sclerosis are characterized by the loss of selected neuronal populations. Another striking feature shared by these diseases is the deposition of proteinaceous inclusion bodies in the brain, which may be intracytoplasmatic or intranuclear, or even extracellular. However, the density and prevalence of aggregates are not always directly related to neurodegeneration. Although some of these diseases are the result of mutations in known proteins, with HD a clear example, the expression and location of the affected protein do not explain the selective neurodegeneration. Therefore, other intrinsic mechanisms, characteristic of each neuronal population, might be involved in the neurodegenerative process. In this review we focus on several proposed mechanisms such as excitotoxicity, mitochondrial dysfunction and altered expression of trophic factors, which could account for the pathogenesis of HD.

Influence of ethanol concentration on the extraction of color and phenolic compounds from the skin and seeds of Tempranillo grapes at different stages of ripening.

The aim of this paper is to study how grape ripeness and ethanol concentration affect the extraction of color and phenolic compounds from skins and seeds during the maceration/fermentation process. Simulated maceration assays were carried out with the grapes at three stages of berry development (vitis vinifera cv. Tempranillo) and different percentages of ethanol in the maceration media. Both ripeness and ethanol content have a considerable effect on the extraction of color and phenolic compounds. Of these two factors, ripeness increases the extractability most. The presence of ethanol in the medium facilitates anthocyanin and especially proanthocyanidin extraction, but it also decreases copigmentation phenomena, which can decrease the color intensity. The higher the ethanol concentration is in the maceration media, the higher the astringency of proanthocyanidins.

Neuroprotection by neurotrophins and GDNF family members in the excitotoxic model of Huntington's disease.

Huntington's disease is a neurodegenerative disorder characterized by a selective degeneration of striatal projection neurons, which deal with choreic movements. Neuroprotective therapy could be achieved with the knowledge of the specific trophic requirements of these neuronal populations. Thus, the induction of endogenous trophic response or the exogenous administration of neurotrophic factors may help to prevent or stop the progression of the illness. Excitotoxicity has been implicated in the etiology of Huntington's disease, because intrastriatal injection of glutamate receptor agonists reproduces some of the neuropathological features of this disorder. Activation of glutamate receptors in the striatum differentially regulates the expression of neurotrophins, glial cell line-derived neurotrophic factor (GDNF), neurturin, and their receptors in the striatum and in its connections, cortex, and substantia nigra, showing a selective trophic response against excitotoxic insults. Transplantation of cells genetically engineered to release neurotrophic factors in the striatum has been used to study the neuroprotective effects of neurotrophin and GDNF family members in the excitotoxic model of Huntington's disease. Neurotrophins (brain-derived neurotrophic factor [BDNF], neurotrophin-3, and neurotrophin-4) protected striatal projection neurons against quinolinic or kainic acid treatment. However, GDNF family members showed a more specific action. Neurturin only protected gamma-aminobutyric acid (GABA)/enkephalinergic neurons that project to the external segment of the globus pallidus, whereas GDNF exerts its effects on GABA/substance P positive neurons, which project to the substantia nigra pars compacta and the internal segment of the globus pallidus. In conclusion, the trophic requirements of each population of striatal projection neurons are due to a complex interaction between several neurotrophic factors, such as neurotrophins and GDNF family members, which can be modified, in different pathological conditions. Moreover, these neurotrophic factors may be able to provide selective protection for basal ganglia circuits, which are affected in striatonigral degenerative disorders, such as Huntington's disease or multisystem atrophy.

TrkB and TrkC are differentially regulated by excitotoxicity during development of the basal ganglia.

During development neurons are protected against various insults by intrinsic properties. Here we evaluate trkB (both full-length and truncated forms) and trkC expression in the striatum, cortex, and substantia nigra after intrastriatal injection of quinolinic acid (QUIN) at different stages of postnatal (P) development, by RNase protection assay and in situ hybridization. During normal development, a region-specific regulation of trkB and trkC was observed, showing the maximal mRNA levels at P5. Excitotoxic lesion did not modify striatal trkB mRNA levels at any age examined. However, trkC decreased after QUIN injection at P5 in the striatum (52 +/- 2% of control levels). On the other hand, regulation of trkB and trkC expression was observed in cortex and substantia nigra after striatal excitotoxic lesion. Both full-length and truncated receptor isoforms of trkB were enhanced in the cortex when striatal injury was produced at P21 (268 +/- 38 and 206 +/- 35%) or P30 (174 +/- 35 and 157 +/- 13%). In situ hybridization studies localized this increase in trkB expression in layers II/III and V along the cerebral cortex. Within the substantia nigra, striatal excitotoxicity at P5 selectively decreased the truncated form of trkB (70 +/- 7%), whereas the full-length form was up-regulated at P30 (130 +/- 2%). A biphasic increase in trkC mRNA levels was observed at P5 (151 +/- 3%) and P21 (168 +/- 4%). These changes were localized in the substantia nigra pars compacta. Triple-labeling studies disclosed that all these changes were mainly located in neurons. These results demonstrate that the endogenous response to excitotoxicity includes transneuronal regulation of neurotrophin receptors, which is specific for each nucleus and depends on the developmental stage.

Distinct roles of the Y1 and Y2 receptors on neuropeptide Y-induced sensitization to sedation.

Intracranial injection of neuropeptide Y (NPY) increases the sensitivity to sodium pentobarbital and ketamin sedation and has similar properties as GABA agonists on sleep. Mice sensitive to sedation have increased levels of NPY in many brain regions and Y1(-/-) mice show a marked resistance to barbiturates. Here we characterized the role of the NPY Y receptors in anesthetic-induced sedation. We show that Y1 and Y2, but not Y5, receptors participate in the modulation of sedation. Administration of a Y1 agonist increased the sodium pentobarbital-induced sedation and Y1(-/-) mice were less sensitive to this anesthetic. However, Y2(-/-) mice display increased sensitivity, showing that Y2 modulates GABAergic induced sedation both pharmacologically and physiologically and has a functionally opposing role to the Y1 receptor. Analysis of Y1(-/-)/Y2(-/-) double mutant mice show that increased sensitivity by Y1 occurs independent of the Y2 receptor, while the decreased sensitivity mediated by Y2 depend on an intact Y1 receptor. In contrast to sodium pentobarbital, both Y1 and Y2 receptors increase the sensitivity in a collaborative fashion to NMDA antagonist-induced sedation. These data demonstrate the physiological and pharmacological impact of the Y1 and Y2 receptors on sedation.

Neuroprotection through delivery of glial cell line-derived neurotrophic factor by neural stem cells in a mouse model of Parkinson's disease.

Neural stem cells (NSCs) have been proposed as tools for treating neurodegeneration because of their capacity to give rise to cell types appropriate to the structure in which they are grafted. In the present work, we explore the ability of NSCs to stably express transgenes and locally deliver soluble molecules with neuroprotective activity, such as glial cell line-derived neurotrophic factor (GDNF). NSCs engineered to release GDNF engrafted well in the host striatum, integrated and gave rise to neurons, astrocytes, and oligodendrocytes, and maintained stable high levels of GDNF expression for at least 4 months. The therapeutic potential of intrastriatal GDNF-NSCs grafts was tested in a mouse 6-hydroxydopamine model of Parkinson's disease. We found that GDNF-NSCs prevented the degeneration of dopaminergic neurons in the substantia nigra and reduced behavioral impairment in these animals. Thus, our results demonstrate that NSCs efficiently express therapeutic levels of GDNF in vivo, suggesting a use for NSCs engineered to release neuroprotective molecules in the treatment of neurodegenerative disorders, including Parkinson's disease.

Neuropeptide Y alters sedation through a hypothalamic Y1-mediated mechanism.

Neuropeptide Y (NPY) has been reported to profoundly influence and regulate brain circuits involved in a number of behaviours, like anxiety, alcohol intake, pain and energy homeostasis. Here we show that NPY increases sedation induced by different types of anaesthetics through interactions with the Y1 receptor. Consistently, in Y1-/- (homozygote knockout) mice NPY does not potentiate the pentobarbital-induced sedation. Similar results were obtained for avertin but not for ketalar- (NMDA antagonist) induced sedation. Local microinjection of NPY exhibited the strongest potentiating effect on pentobarbital-induced sedation in the posterior hypothalamic area and Y1 expression was found in the dorsal-premammillary and medial part of medial mammillary nuclei. These results show that Y1 is essential for NPY-induced enhancement of sedation and place this activity of NPY in the posterior hypothalamic area, a region of the brain previously implicated in the regulation of the wake-sleep cycle.