RESUMEN
Common pharmacological treatments of mood disorders aim to modulate serotonergic neurotransmission and enhance serotonin levels in the brain. Brain serotonin levels are dependent on the availability of its food-derived precursor essential amino acid tryptophan (Trp). We tested the hypothesis that delivery of Trp via food may serve as an alternative treatment, and examined the effects of a Trp-rich, bioavailable dietary supplement from egg protein hydrolysate on cognitive and emotional functions, mood state, and sleep quality. In a randomised, placebo-controlled, parallel trial, fifty-nine mentally and physically healthy women aged 45-65 years received placebo (n 30) or the supplement (n 29) (both as 0.5 g twice per d) for 19 d. Emotional processing was significantly changed by supplementation, exhibiting a shift in bias away from negative stimuli. The results for the Affective Go/No-Go Task exhibited a slowing of responses to negative words, suggesting reduced attention to negative emotional stimuli. The results for the Facial Emotional Expression Rating Task also supported a shift away from attention to negative emotions and a bias towards happiness. An increase in arousal-like symptoms, labelled 'high energy', shorter reaction times and a slight benefit to sustained attention were observed in the treated subjects. Finally, when the supplement was taken 60-90 min before bedtime, a feeling of happiness before going to bed was consistently reported. In summary, daily consumption of a low-dose supplement containing bioavailable Trp may have beneficial effects on emotional and cognitive functions.
Asunto(s)
Disfunción Cognitiva/prevención & control , Suplementos Dietéticos , Proteínas Dietéticas del Huevo/uso terapéutico , Fatiga Mental/prevención & control , Hidrolisados de Proteína/uso terapéutico , Estrés Psicológico/prevención & control , Triptófano/uso terapéutico , Anciano , Antidepresivos/efectos adversos , Antidepresivos/sangre , Antidepresivos/metabolismo , Antidepresivos/uso terapéutico , Bebidas , Disfunción Cognitiva/sangre , Disfunción Cognitiva/metabolismo , Estudios de Cohortes , Depresión/sangre , Depresión/metabolismo , Depresión/prevención & control , Suplementos Dietéticos/efectos adversos , Método Doble Ciego , Proteínas Dietéticas del Huevo/efectos adversos , Proteínas Dietéticas del Huevo/metabolismo , Metabolismo Energético , Femenino , Humanos , Fatiga Mental/sangre , Fatiga Mental/metabolismo , Persona de Mediana Edad , Nootrópicos/efectos adversos , Nootrópicos/sangre , Nootrópicos/metabolismo , Nootrópicos/uso terapéutico , Hidrolisados de Proteína/efectos adversos , Hidrolisados de Proteína/metabolismo , Escalas de Valoración Psiquiátrica , Tiempo de Reacción , Serotoninérgicos/efectos adversos , Serotoninérgicos/sangre , Serotoninérgicos/metabolismo , Serotoninérgicos/uso terapéutico , Trastornos del Sueño-Vigilia/sangre , Trastornos del Sueño-Vigilia/metabolismo , Trastornos del Sueño-Vigilia/prevención & control , Estrés Psicológico/sangre , Estrés Psicológico/metabolismo , Triptófano/efectos adversos , Triptófano/sangre , Triptófano/metabolismoRESUMEN
The importance of the gut microbiota community on host's health and disease has long been recognised and is well documented. The development of pro- and prebiotic interventions offers an opportunity for the modulation of the gut microbiota towards long lasting health. In vitro fermentation models were developed as a powerful tool to study the impact of pro- and prebiotics on the gut microbiota under tightly controlled conditions, which allow dynamic sampling over time in reactors mimicking different colon regions. These models have been further evolved to suit specific experimental purposes, e.g. including immobilised faecal microbiota, peristaltic movement, mucin microcosm and the ability to perform treatments in parallel. In this review we discuss the advantages, disadvantages and technical considerations of the most frequently used models. We further focus on recent advances in the application of these models in prebiotics and probiotics research and outline their predictability for clinical research.
Asunto(s)
Microbioma Gastrointestinal/efectos de los fármacos , Intestinos/microbiología , Modelos Biológicos , Prebióticos/análisis , Probióticos/farmacología , Evaluación Preclínica de Medicamentos , Humanos , Probióticos/análisisRESUMEN
BACKGROUND: Aging is a highly complex biological process driven by multiple factors. Its progression can partially be influenced by nutritional interventions. Vitamin E is a lipid-soluble anti-oxidant that is investigated as nutritional supplement for its ability to prevent or delay the onset of specific aging pathologies, including neurodegenerative disorders. PURPOSE: We aimed here to investigate the effect of vitamin E during aging progression in a well characterized mouse model for premature aging. METHOD: Xpg-/- animals received diets with low (~2.5 mg/kg feed), medium (75 mg/kg feed) or high (375 mg/kg feed) vitamin E concentration and their phenotype was monitored during aging progression. Vitamin E content was analyzed in the feed, for stability reasons, and in mouse plasma, brain, and liver, for effectiveness of the treatment. Subsequent age-related changes were monitored for improvement by increased vitamin E or worsening by depletion in both liver and nervous system, organs sensitive to oxidative stress. RESULTS: Mice supplemented with high levels of vitamin E showed a delayed onset of age-related body weight decline and appearance of tremors when compared to mice with a low dietary vitamin E intake. DNA damage resulting in liver abnormalities such as changes in polyploidy, was considerably prevented by elevated amounts of vitamin E. Additionally, immunohistochemical analyses revealed that high intake of vitamin E, when compared with low and medium levels of vitamin E in the diet, reduces the number of p53-positive cells throughout the brain, indicative of a lower number of cells dying due to DNA damage accumulated over time. CONCLUSIONS: Our data underline a neuroprotective role of vitamin E in the premature aging animal model used in this study, likely via a reduction of oxidative stress, and implies the importance of improved nutrition to sustain health.
Asunto(s)
Envejecimiento Prematuro/dietoterapia , Envejecimiento Prematuro/patología , Encéfalo/patología , Muerte Celular , Suplementos Dietéticos , Vitamina E/administración & dosificación , Envejecimiento Prematuro/metabolismo , Animales , Peso Corporal , Encéfalo/metabolismo , Muerte Celular/fisiología , Proteínas de Unión al ADN/deficiencia , Proteínas de Unión al ADN/genética , Modelos Animales de Enfermedad , Ingestión de Alimentos , Endonucleasas/deficiencia , Endonucleasas/genética , Hígado/metabolismo , Hígado/patología , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas Nucleares/deficiencia , Proteínas Nucleares/genética , Estrés Oxidativo/fisiología , Distribución Aleatoria , Factores de Tiempo , Factores de Transcripción/deficiencia , Factores de Transcripción/genética , Temblor/dietoterapia , Temblor/metabolismo , Temblor/patología , Vitamina E/metabolismoRESUMEN
Effects of ex vivo GDNF gene delivery on the degeneration of motoneurons were studied in the G1H transgenic mouse model of familial ALS carrying a human superoxide dismutase (SOD1) with a Gly93Ala mutation (Gurney et al., 1994). Retroviral vectors were made to produce human GDNF or E. coli beta-galactosidase (beta-Gal) by transient transfection of the Phoenix cell line and used to infect primary mouse myoblasts. In 6-week-old G1H mice, 50,000 myoblasts per muscle were injected bilaterally into two hindlimb muscles. Untreated G1H and wild-type mice served as additional controls. At 17 weeks of age, 1 week before sacrifice, these muscles were injected with fluorogold (FG) to retrogradely label spinal motoneurons that maintained axonal projections to the muscles. There were significantly more large FG-labeled alpha motoneurons at 18 weeks in GDNF-treated G1H mice than in untreated and beta-Gal-treated G1H mice. A morphometric study of motoneuron size distribution showed that GDNF shifted the size distribution of motoneurons toward larger cells compared with control G1H mice, although the average size and number of large motoneurons in GDNF-treated mice were less than that in wild-type mice. GDNF also prolonged the onset of disease, delayed the deterioration of performance in tests of motor behavior, and slowed muscle atrophy. Quantitative, real-time RT-PCR and PCR showed persistence of transgene mRNA and DNA in muscle for up to 12 weeks postgrafting. These observations demonstrate that ex vivo GDNF gene therapy in a mouse model of FALS promotes the survival of functional motoneurons, suggesting that a similar approach might delay the progression of neurodegeneration in ALS.
Asunto(s)
Esclerosis Amiotrófica Lateral/terapia , Trasplante de Células , Terapia Genética , Músculo Esquelético/citología , Factores de Crecimiento Nervioso , Proteínas del Tejido Nervioso/genética , Animales , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Vectores Genéticos , Factor Neurotrófico Derivado de la Línea Celular Glial , Humanos , Ratones , Neuronas Motoras/fisiología , Músculo Esquelético/trasplante , Proteínas del Tejido Nervioso/metabolismo , Retroviridae/genética , Transducción Genética , beta-Galactosidasa/genética , beta-Galactosidasa/metabolismoRESUMEN
We used pilocarpine-induced seizures in mice to determine the impact of genetic background on the vulnerability of hippocampal neurons and associated changes of behavioral performance. The susceptibility of hippocampal neurons to seizure-induced cell death paralleled the severity of the seizures and depended on genetic background. Hippocampal neurons in C57BL/6 mice were most resistant to cell death, whereas they were highly vulnerable in FVB/N mice. The degree of neuronal degeneration in F1 hybrid mice obtained by crossing the two strains was at an intermediate level between the parent strains. Two weeks after the severe seizures, performance in a water-maze place navigation task showed a bimodal distribution. Seventeen of 19 (90%) F1 mice were completely unable to learn while the other two learned reasonably well. Of 28 C57BL/6 mice with similarly severe seizures, six were as strongly impaired as their F1 counterparts (22%). The remaining 22 performed normally, indicating a much lower probability of C57BL/6 mice to be affected. Treated mice showed a deficit of open-field exploration which was strongly correlated with the impairment in the place navigation task and was again more severe in F1 mice. Our results show that the vulnerability of hippocampal neurons to pilocarpine-induced seizures, as well as the associated behavioral changes, depended on genetic background. Furthermore, they confirm and extend our earlier finding that a relatively modest reduction of hippocampal cell death can be associated with dramatic changes of behavioral performance and emphasize the importance of tightly-controlled genetic backgrounds in biological studies.
Asunto(s)
Hipocampo/patología , Aprendizaje por Laberinto , Degeneración Nerviosa/genética , Células Piramidales/patología , Convulsiones/genética , Convulsiones/patología , Animales , Muerte Celular , Convulsivantes , Cruzamientos Genéticos , Conducta Exploratoria , Predisposición Genética a la Enfermedad , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos , Degeneración Nerviosa/patología , Pilocarpina , Convulsiones/inducido químicamente , Especificidad de la EspecieRESUMEN
Glial cell line-derived neurotrophic factor (GDNF) is a potent survival factor for motoneurons (MN) and dopaminergic (DA) neurons, neurons which selectively die in amyotrophic lateral sclerosis (ALS) and Parkinson's disease (PD). GDNF gene delivery has been studied in rodent models of ALS and PD. In a mouse model of ALS, implantation of myoblasts retrovirally transduced with GDNF into hindlimb muscles at 6 weeks of age, i.e. prior to the onset of disease symptoms, increased the number of large MNs that maintained projections to treated muscles at 18 weeks of age. GDNF-treated mice also performed better on tests of motor function and had a delayed onset of disease. In a progressive degeneration rat model of PD, effects of in vivo GDNF gene therapy using an adenoviral vector (AdGDNF) were studied in young and aged rats. AdGDNF protected DA neurons against the neurotoxin, 6-hydroxydopamine (6-OHDA), and was effective whether injected either before or after 6-OHDA damage had commenced. However, if AdGDNF was injected prior to 6-OHDA, it was most effective in protecting against DA-dependent changes in the brain when injected near the terminals of the DA neurons. In contrast, if 6-OHDA damage had already commenced, AdGDNF was most effective if injected near the DA soma. These studies suggest that GDNF gene delivery into specific sites in the CNS or into muscle where MNs have access to secreted GDNF may slow the progression of PD and ALS, respectively. Neurotrophic factor gene therapy offers novel interventions not only for PD and ALS, but also other neurodegenerative diseases and injuries to the nervous system.
Asunto(s)
Esclerosis Amiotrófica Lateral/terapia , Técnicas de Transferencia de Gen , Terapia Genética , Factores de Crecimiento Nervioso , Fármacos Neuroprotectores , Trastornos Parkinsonianos/terapia , Animales , Modelos Animales de Enfermedad , Factor Neurotrófico Derivado de la Línea Celular Glial , Proteínas del Tejido Nervioso/genéticaRESUMEN
RATIONALE: Effective functioning of the neurotransmitter serotonin is important for optimal cognitive and emotional function. Dietary supplements able to increase availability to the brain of the precursor amino acid, tryptophan (TRP), and thereby enhance serotonin synthesis, can have measurable impact on these psychological processes. OBJECTIVES: This study involves a randomised controlled trial of a TRP-rich egg-white protein hydrolysate (DSM Nutritional Products Ltd., Switzerland) on plasma amino acids, cognition, mood and emotional processing in older women. METHODS: Following a baseline test day without treatment, 60 healthy women aged 45-65 years received drinks containing either 2 or 4 g of TRP-rich protein hydrolysate product or 3.11 g casein hydrolysate as a control. One hour later, they undertook a 2-h battery of cognitive and emotional tests. RESULTS: The TRP-rich protein hydrolysate produced the expected dose-dependent increase in the ratio of plasma TRP to competing large neutral amino acids. TRP-rich protein hydrolysate (2 g only) prevented both the decline in wellbeing and increase in fatigue seen over the test session in the control group. This treatment dose resulted in a significant shift in emotional processing towards positive words and reduced negative bias in assessing negative facial expressions. Effects on cognition were small and not statistically reliable and are not reported here. However, there was no evidence for any adverse effects. CONCLUSIONS: Consumption of a low dose of TRP-rich protein hydrolysate may have beneficial effects on emotional function that could promote feelings of wellbeing, possibly conferring resistance to deterioration in mood in healthy subjects or depressive episodes.
Asunto(s)
Afecto/efectos de los fármacos , Aminoácidos/sangre , Suplementos Dietéticos , Emociones/efectos de los fármacos , Hidrolisados de Proteína/farmacología , Anciano , Caseínas , Cognición/efectos de los fármacos , Método Doble Ciego , Femenino , Humanos , Persona de Mediana Edad , Pruebas Neuropsicológicas , Serotonina/metabolismo , Triptófano/sangreRESUMEN
The cleavage of APP by BACE initiates the amyloidogenic process in Alzheimer's disease (AD). We have generated transgenic mice expressing BACE and double transgenic mice expressing BACE and the Swedish mutations of APP (SwAPP) in neurons. BACE transgenic mice did not develop beta-amyloid plaques by age of 14 months, but showed intracellular beta-amyloid immunoreactivity that was co-localized with transgenic BACE in neurons. Abeta levels were increased and AD-like pathology was accelerated in double transgenic mice expressing both BACE and SwAPP. At two months of age, early signs of extracellular Abeta deposition and reactive astrocytes were found in double transgenic, but not in single transgenic mice. Furthermore, at four months, well defined beta-amyloid deposits surrounded by activated astrocytes could be detected in the double transgenic mice. We suggest that BACE overexpression is not sufficient to produce beta-amyloid plaques, but simultaneous expression of BACE and its substrate (SwAPP) leads to an accelerated amyloid plaque formation.
Asunto(s)
Ácido Aspártico Endopeptidasas/metabolismo , Encéfalo/metabolismo , Encéfalo/patología , Neuronas/metabolismo , Neuronas/patología , Placa Amiloide/patología , Secretasas de la Proteína Precursora del Amiloide , Péptidos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animales , Ácido Aspártico Endopeptidasas/genética , Western Blotting , Endopeptidasas , Ensayo de Inmunoadsorción Enzimática , Humanos , Inmunohistoquímica , Ratones , Ratones Transgénicos , MutaciónRESUMEN
Mutations in the superoxide dismutase gene 1 (SOD-1) are found in patients with familial amyotrophic lateral sclerosis (FALS). Overexpression of a mutated human SOD-1 gene in mice results in neurodegenerative disease as result of motoneuron loss in lumbar spinal cord (10). Using this mouse model of FALS, we have established a quantitative assay utilizing the retrograde tracer Fluorogold (FG) to determine the number of motoneurons innervating one skeletal muscle in mice with ongoing disease. In adult wild-type mice, the number of alpha motoneurons retrogradely labeled by an injection of FG into medial gastrocnemius muscle is 50 +/- 7 and this number remains constant from 7 to 18 weeks of age. In mutant mice, the number of alpha motoneurons retrogradely labeled by FG is the same as in wild-type mice at 7 and 9 weeks, but then declines to 36% of that in normal mice at 18 weeks. This decline also correlates positively to severity of motor impairments in these mice as assessed by the hindlimb splay test. In contrast, the number of FG-labeled gamma motoneurons remains relatively unchanged in both wild-type and mutant mice up to 18 weeks. At 18 weeks of age, this apparent alpha motoneuron denervation is paralleled by an average of 55% reduction of MG-muscle mass and 40% weaker performance in the hindlimb splay test. These data suggest that alpha motoneurons are the most vulnerable neuronal subtype in this mouse model of ALS and it is primarily their loss that leads to functional motor deficits. This quantitative bioassay also will be valuable for evaluating novel therapeutics for ALS.
Asunto(s)
Esclerosis Amiotrófica Lateral/patología , Neuronas Motoras/patología , Músculo Esquelético/inervación , Estilbamidinas , Envejecimiento , Esclerosis Amiotrófica Lateral/enzimología , Esclerosis Amiotrófica Lateral/fisiopatología , Animales , Transporte Axonal , Colina O-Acetiltransferasa/análisis , Modelos Animales de Enfermedad , Colorantes Fluorescentes , Humanos , Ratones , Ratones Transgénicos , Neuronas Motoras/fisiología , Desarrollo de Músculos , Músculo Esquelético/crecimiento & desarrollo , Nervios Periféricos/crecimiento & desarrollo , Nervios Periféricos/patología , Nervios Periféricos/fisiopatología , Mutación Puntual , Reacción en Cadena de la Polimerasa , Valores de Referencia , Superóxido Dismutasa/biosíntesis , Superóxido Dismutasa/genéticaRESUMEN
To gain insight into the molecular mechanisms underlying the regulation of expression of the neural cell adhesion molecule L1 and into the exon-intron structure of the L1 gene, a genomic clone from the mouse was characterized. The clone was identified by screening an EMBL3 library with an L1-specific cDNA probe and comprises approximately 15 kb, in which the first 2,206 nucleotides of the coding region are included. Of the 5 of 6 immunoglobulin (Ig)-like domains sequenced, all are encoded by 2 exons, with the first exon being smaller than the second. The exon encoding the signal peptide is separated from a mini-exon containing 15 bp by a large intron, approximately 2.6 kb in length, whereas the other introns are smaller, with the coding information for the Ig-like domains 3-5 clustered in a 1,643-bp-long fragment with introns only 110-217 bp in length. The 5' upstream region of the clone comprises 5 kb, with the first 112 bp lying upstream to the coding sequence and containing a start site for transcription. No consensus sequence for a TATA box was found. Consensus DNA sequences for the binding of the gene products of Hox 1.3, engrailed and bicoid, are localized upstream to the transcription start site. A 1,262-bp fragment containing part of the first exon showed promoter activity in neuroblastoma cells, but hardly in L cells and not in CHO cells, indicating that this fragment is sufficient for neural cell directed promoter activity.
Asunto(s)
Moléculas de Adhesión Celular Neuronal/genética , Regiones Promotoras Genéticas , Animales , Secuencia de Bases , Clonación Molecular , Exones , Genoma , Complejo de Antígeno L1 de Leucocito , Luciferasas/genética , Ratones , Ratones Endogámicos C57BL , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Oligonucleótidos , Sondas ARN , Ribonucleasas/antagonistas & inhibidores , Ribonucleasas/metabolismo , Transcripción GenéticaRESUMEN
In search for the molecular mechanisms underlying the formation of the major dense line in peripheral nerve myelin we investigated mice deficient in the myelin proteins P0 and MBP. In mice lacking both molecules axons were enwrapped by myelin-like processes devoid of the major dense line, while mice deficient in either protein showed, respectively, partial and normal compaction. Mice heterozygous for P0 but devoid of MBP showed myelin of reduced thickness around axons of normal caliber. Both molecules thus contribute to the formation of the major dense line and to the determination of myelin thickness. Furthermore, our observations modify the view that axon caliber is dependent on normal myelin.
Asunto(s)
Ratones Mutantes Neurológicos/fisiología , Proteína Básica de Mielina/deficiencia , Proteínas de la Mielina/deficiencia , Vaina de Mielina/fisiología , Vaina de Mielina/ultraestructura , Nervios Periféricos/fisiología , Animales , Moléculas de Adhesión Celular Neuronal/genética , Genotipo , Ratones , Ratones Noqueados , Microscopía Electrónica , Proteína Básica de Mielina/genética , Proteína P0 de la Mielina , Proteínas de la Mielina/genética , Nervios Periféricos/ultraestructura , Fenotipo , Valores de Referencia , Nervio Ciático/fisiología , Nervio Ciático/ultraestructuraRESUMEN
Cystatin C is an essential secretory cofactor for neurogenesis with potent protease inhibitor activities. Polymorphisms of cystatin C are genetically associated with Alzheimer's disease (AD), and the L68Q mutation causes hereditary cerebral hemorrhage with amyloidosis of the Icelandic type, in which cystatin C and beta-amyloid are colocalized in cortical blood vessels. To determine whether cystatin C and beta-amyloid also colocalize in brain amyloid plaques, we analyzed transgenic mice expressing the Swedish APP (SweAPP) mutation. We found high levels of cystatin C in astrocytes surrounding beta-amyloid plaques, and discrete layers of cystatin C attached to amyloid plaque cores covered by a layer of beta-amyloid. In addition, cystatin C accumulated in reactive astrocytes throughout the brain, independently of, and before the onset of, amyloid plaque formation. These results show that expression of SweAPP is associated with increased cystatin C in reactive astrocytes, and they suggest an early role of cystatin C in appositional amyloid plaque growth.
Asunto(s)
Enfermedad de Alzheimer/metabolismo , Precursor de Proteína beta-Amiloide/genética , Astrocitos/metabolismo , Cistatinas/metabolismo , Enfermedad de Alzheimer/patología , Precursor de Proteína beta-Amiloide/análisis , Animales , Astrocitos/patología , Encéfalo/metabolismo , Encéfalo/patología , Cistatina C , Cistatinas/análisis , Expresión Génica , Ratones , Ratones Transgénicos , Mutagénesis , Placa Amiloide/química , Placa Amiloide/metabolismo , Placa Amiloide/patologíaRESUMEN
Axonal regrowth in the lesioned central nervous system (CNS) of adult mammals is, in part, prevented by non-permissive properties of glial cells and myelin. To test if ectopic expression of the neurite outgrowth promoting recognition molecule L1 will overcome these non-permissive influences and promote neurite outgrowth, L1 was expressed in astrocytes of transgenic mice using regulatory sequences of the glial fibrillary acidic protein (GFAP) gene. Northern blot analysis of different transgenic lines revealed different levels of transgenically expressed L1. Cultured astrocytes derived from transgenic animals displayed L1 immunoreactivity at the cell surface and in situ hybridization and immunocytochemical analysis of optic nerves from adult transgenic mice localized L1 expression to astrocytes. Expression of L1 protein by transgenic astrocytes was significantly upregulated in lesioned optic nerves. When mouse small cerebellar neurons or chick dorsal root ganglion neurons were cultured on cryosections of lesioned optic nerves or astrocyte monolayers from transgenic mice, respectively, neurite outgrowth was increased up to 400% on tissue sections and 50% on astrocytes compared with similar preparations from non-transgenic mice. The increase in neurite outgrowth on tissue sections or astrocyte monolayers from different transgenic lines was proportional to the different levels of L1 expression. Moreover, increased neurite outgrowth on these substrates was specifically inhibited by polyclonal L1 antibodies. In vivo, rescue of severed axons was enhanced in transgenic versus wild type animals, while regrowth of axons was slightly, but not significantly, increased. Together, our observations demonstrate that L1 promotes neurite outgrowth when expressed ectopically by astrocytes and that L1 is able to overcome, at least partially, the non-permissive substrate properties of differentiated CNS glial cells in vitro.