Introdução: Em humanos, sugere-se que um trauma precoce está relacionado com o desenvolvimento de transtornos de ansiedade na vida adulta. Essa relação poderia ser mediada pela resposta ao estresse, fator neurotrófico derivado do encéfalo (BDNF) e/ou óxido nítrico sintase neuronal (nNOS). O objetivo deste trabalho foi propor um modelo animal para o desenvolvimento de ansiedade, utilizando, como intervenção, um ambiente neonatal hostil que afeta o cuidado materno, além de verificar potenciais mecanismos relacionados ao desenvolvimento de ansiedade. Também objetivou-se investigar associações similares em humanos. Métodos: Ao segundo dia de vida, ninhadas de ratos Wistar e suas genitoras foram divididas em dois grupos: grupo intervenção, com redução do material disponível para a confecção do ninho, ou grupo controle. O comportamento materno foi observado do dia 1 ao dia 9 de vida. Após o desmame, o peso corporal e o consumo de ração padrão foram avaliados uma vez por semana. Na vida adulta, os ratos foram submetidos a testes comportamentais. Foram determinados os níveis plasmáticos de glicose e o perfil lipídico, além da quantidade de BDNF no plasma, hipocampo, amígdala e sustância cinzenta periaquedutal e de óxido nítrico no hipocampo. Um subgrupo de animais intactos foi submetido ao estresse por restrição para avaliação da curva de corticosterona. Em humanos, 129 adolescentes com sintomas ansiosos, avaliados pela escala Screen for Children and Anxiety Related Emotional Disorders (SCARED), responderam ao Parental Bonding Instrument (PBI), coletaram sangue para avaliação do BDNF e foram genotipados para o polimorfismo Val66Met do BDNF. Resultados: As genitoras do grupo intervenção apresentaram um maior contato de baixa qualidade com seus filhotes, comparadas às genitoras controles. O consumo alimentar de ração padrão foi menor no grupo intervenção. Não houve diferença entre os grupos no peso corporal, no consumo de alimento palatável, na hiperfagia de rebote, nem no teste do campo aberto. No teste do labirinto em cruz elevado, observou-se que a intervenção esteve associada a maior ansiedade, porém de forma diferenciada entre os sexos. Foram observados níveis maiores de BDNF plasmáticos no grupo intervenção e uma correlação positiva entre o contato de baixa qualidade e o BDNF periférico. Não houve diferença entre os grupos na quantidade de BDNF no hipocampo, amígdala e sustância cinzenta periaquedutal e, também, nos níveis de óxido nítrico no hipocampo. Machos do grupo intervenção levaram mais tempo para atingir o pico de corticosterona em resposta ao estresse. No estudo clínico, observaram-se correlações negativas entre o cuidado materno e sintomas ansiosos, assim como uma correlação positiva entre a superproteção materna e os níveis periféricos de BDNF apenas nos indivíduos portadores do alelo Met. Conclusão: O modelo animal proposto mostrou que o estresse precoce, capaz de alterar a relação mãe-filhote, tem impacto persistente sobre o comportamento do tipo ansioso e os níveis periféricos de BDNF. Estes achados são similares às associações descritas em humanos. A abordagem translacional da questão evidenciou que os efeitos do trauma no início da vida podem ser mediados pelo cuidado materno, sendo o aumento do BDNF periférico um marcador em potencial para esses indivíduos. / Introduction: In humans, there is the suggestion that an adverse early life environment is related to the development of anxiety disorders in adulthood. This association could potentially be mediated by stress responses, brain-derived neurotrophic factor (BDNF) and by neuronal nitric oxide synthase (nNOS). This study aimed at proposing an animal model for the development of adult anxiety-like behavior, using as intervention an adverse early life environment affecting matenal care, and verifies potencial mechanisms related to the development of anxiety-like behavior. Another aim was investigate similar associations in humans. Methodology: By the second day of life, litters of Wistar rats and their dams where divided in two groups: intervention, with limited access to nesting material, or control. Maternal behavior was observed from day 1 to day 9 of life. After weaning, animals’ weight and standard chow consumption were measured once a week. Starting on day 60 of life, rats were submitted to behavioral testing. Glucose and lipid profile were assessed. Plasma, hippocampus, amygdala and periaqueductal gray BDNF contents and hippocampus nitric oxide were also measured. A subgroup of naive animals was submitted to restraint stress for determination of corticosterone curve. In humans, 129 adolescents, screened for anxiety using the Screen for Children and Anxiety Related Emotional Disorders (SCARED) scale, responded to the Parental Bonding Instrument (PBI), collected blood for BDNF measurements and were genotyped for BDNF Val66Met polymorphism. Results: Intervention dams showed increased contact of low quality with their pups when compared to control dams. The intervention group consumed less standard chow than the control group. No differences in body weight gain, acute palatable food consumption, rebound hyperphagia and open field test were observed between groups. On plus maze test, the intervention was associated with higher anxiety-like behavior, however differently between the sexes. Higher plasma BDNF levels were found in the intervention group and low quality maternal care (pure contact) was positively correlated with adult peripheral BDNF. There were no differences in hippocampus, amygdala and periaqueductal gray BDNF contents, as hippocampus nitric oxide contents. Males of the intervention group took longer to reach the corticosterone peak. In humans, negative correlations between maternal care and anxiety symptoms were observed, as well as a positive correlation between overprotection and serum BDNF levels only among the Met carriers. Conclusion: The animal model proposed showed that an early life stress, able to alter the relationship between dam and pup, have a persistent impact on anxiety-like behavior and peripheral BDNF levels. These findings were similar to the associations described in humans. The translational approach to the question evidenced that the effects of early trauma may be mediated through maternal care, being the increased peripheral BDNF a potential relevant marker for these individuals.

Introdução: Existem fortes evidências de um fator genético estar envolvido na etiologia do transtorno bipolar (TB), contudo a interação entre polimorfismos genéticos e alterações bioquímicas permanecem desconhecidas. O fator neurotrófico derivado do cérebro (BDNF) parece exercer um papel importante na patofisiologia do TB. Objetivos: O presente estudo tem por objetivo avaliar a associação do polimorfismo localizado no gene do fator neurotrófico derivado do cérebro (BDNF) e os níveis séricos desta substância em pacientes com transtorno bipolar. Material e Métodos: Foram selecionados 114 pacientes com TB tipo I de acordo com critério do DSMIV e 137 controles pareados por sexo, idade e anos de estudo para a análise do polimorfismo val66met do BDNF e do BDNF sérico. Suas associações foram medidas através da análise de variância (ANOVA).Resultados: Não houve diferenças significativas na freqüência dos genótipos do polimorfismo val66met do BDNF entre pacientes e controles (p>0.05; teste Qui-quadrado). Não foi encontrada associação entre o polimorfismo do gene do BDNF e o diagnósticode transtorno bipolar(eutímicos) nos níveis séricos de BDNF (p=0.34; ANOVA Fatorial) Conclusão: O polimorfismo do BDNF val66met parece não interferir no nível sérico de BDNF em pacientes bipolares em tratamento e controles sem TB, sugerindo que a variante BDNFMet não diminui a secreção constitutiva; possivelmente este polimorfismo do BDNF exerça alguma influencia nos níveis séricos do BDNF durante os episódios agudos da doença. / Introduction: There is strong evidence demonstrating that genetic inheritance is associated with higher susceptibility to bipolar disorder (BD) but the interaction between gene polymorphisms and biochemical changes remains largely unknown. The brainderived neurotrophic factor (BDNF) may play a role in the pathophysiology of BD. Objectives: The aim of the present study was to evaluate the association between BDNF polymorphism val66met and its serum levels in bipolar patients. Methods: One hundred and seven Caucasian type-I bipolar patients were recruited from the Bipolar Disorders Program and underwent Structured Clinical Interview for DSMIV- Axis I for diagnosis. The subjects were matched by age, gender and education with137 controls without BD. The association between BDNF serum levels and polymorphism was analysed by ANOVA. Results: No significant differences were found in the frequency of the BDNF val66met genotype or allele distribution between patients and controls (p>0.05; Chi-square test). We have found no significant interaction between BDNF polymorphism anddiagnostic status (bipolar disorder and controls) on serum BDNF levels (p=0.34; Factorial ANOVA) Conclusion: BDNF val66met polymorphism does not affect serum BDNF levels in a sample of mostly euthymic BD subjects currently on medication. Considering that the BDNFMet variant decreases only the activity-dependent but not the constitutive BDNF secretion, it is conceivable that BDNF polymorphism may exert some influence on serum BDNF levels during acute mood episodes.

Considerable evidence supports the claim that a hyperactive sympathetic nervous system (SNS) is involved in most cases of human hypertension, and therefore a more thorough understanding of the central regulation of the SNS may help elucidate novel therapeutic options. The PVN is a key region in SNS regulation of blood pressure (BP) and heart rate (HR). Stimulation of the parvocellular PVN neurons has been shown to enhance sympathetic outflow and thereby increase BP. Brain-derived neurotrophic factor (BDNF), a modulator of neuronal activity is upregulated in the paraventricular nucleus of the hypothalamus (PVN) in response to several hypertensive stimuli such as stress and hyperosmolarity, and previous studies from our lab demonstrated that both acute injections or chronic overexpression of BDNF in the PVN elevate SNS activity and BP. However, the BDNF-mediated hypertensive mechanisms are not completely understood. PVN neurons are under tonic inhibition from NTS catecholaminergic projections under baseline condition as indicated by significant BP increase after selective lesioning of NTS NE-ergic neurons. In addition, BDNF has been shown to alter NE-ergic signaling in multiple brain regions raising the possibility that BDNF may increase SNS activity and BP by interfering with NE-ergic inhibition of PVN sympathoregulatory neurons. Therefore, we tested the hypothesis that BDNF increases SNS activity and BP in part by disabling inhibitory actions of NTS catecholaminergic projections to the PVN by altering the expression of adrenergic receptors and NET in the PVN. First, blood pressure was recorded using radiotelemetry in male Sprague-Dawley rats following bilateral microinjections of adeno-associated viral vectors expressing green fluorescent protein (GFP) or myc-tagged BDNF in the PVN and microinjections of phosphate saline buffer (PBS) or Anti-Dopaine Beta Hydroxylase (DBH)-conjugated saporin (DSAP), a catecholaminergic neuron-specific neurotoxin, into the NTS. Blood pressure was monitored both during resting conditions and during acute stress tests. A second group of rats received bilateral microinjections of adeno-associated viral vectors expressing GFP or myc-tagged BDNF in the PVN, and were sacrificed after 5 weeks. PVN and NTS samples were then selectively isolated using a brain punch tool, and expression of TH, DBH, 1a, 1b, 2a, 1, 2 receptors, and norepinephrine transporter (NET) was analyzed using quantitative RT-PCR. Our results show that BDNF overexpression in the PVN leads to increased expression of catecholamine synthesizing enzymes in the NTS. In addition, both BDNF overexpression in the PVN, and DSAP lesioning in the NTS increased MAP compared to control rats. However, combined treatment with BDNF and DSAP failed to have any additional hypertensive effects suggesting that BDNF treatment may abolish the inhibitory effect of NTS catecholaminergic projections. Lesioning the NTS catecholaminergic neurons didn’t appear to have a significant effect on mean arterial pressure response to the stress tests, although DSAP treatment appeared to decrease the initial heart rate response to acute stress, and this effect was most pronounced in GFP rats. These results indicate that BDNF overexpression in the PVN desensitizes sympathoregulatory neurons to inhibitory NTS catecholaminergic projections during baseline conditions.

The purpose of this randomized control study was to examine the effects of the use of a mindfulness smartphone app on student self-reported levels of depression, anxiety, and stress, and serum levels of brain-derived neurotrophic factor (BDNF). The sample included college students enrolled in courses at a university in South Florida. Forty-four students were randomly allocated to either the mindfulness app group (n = 22) or the control group (n = 22). Participants in the mindfulness app group were instructed to complete a guided meditation on the app for 10 minutes per day for 5 weeks. Participants in the control group were offered the intervention after the 5-week protocol ended. A pretest-posttest design was used to investigate the effects of the mindfulness app intervention on self-reported levels of depression, anxiety, and stress, in addition to serum level BDNF. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

The purpose of the present thesis was to propose a guideline to differentiate between an accidental or suicide manner of death when dealing with a drug/ethanol overdose in which all available medical and investigational evidence, including a psychological autopsy, is inconclusive, thereby resulting in an undetermined manner of death. An in-depth literature review was conducted in the field of neuroscience, psychiatry, and pharmacology to discover neuroanatomical markers indicative of suicidal behavior in the context of two major risk factors of suicide, stress and depression, and two hypotheses behind the cause of suicidal behavior, impulsive aggression and neuronal plasticity. The neuroanatomical markers of suicidal behavior, as indicated by the experimental evidence of various studies in suicide subjects, included serotonergic dysfunction, hypothalamic-pituitary-adrenal axis hyperactivity, brain-derived neurotrophic factor deficiency, and the associated anatomical changes in the brain. Upon consideration of the forensic applicability of analyzing these neuroanatomical markers indicative of suicidal behavior, a guideline was generated to differentiate between an accidental and suicide manner of death by showing suicide subjects had significantly decreased messenger ribonucleic acid and protein levels of presynaptic serotonin receptors along with significantly increased messenger ribonucleic acid and protein levels of postsynaptic serotonin receptors in the prefrontal cortex, significantly decreased serum brain-derived neurotrophic factor levels, and significantly decreased messenger ribonucleic acid and protein levels of brain-derived neurotrophic factor and tyrosine kinase B receptors in the prefrontal cortex and hippocampus when compared to the levels of both depressed non-suicidal individuals and healthy controls. Given the significant difference observed between suicide subjects and controls, these differences in neuroanatomical markers may play an important role in the pathophysiology of suicidal behavior and have the potential to be used in establishing the intention of an individual in an overdose death to distinguish between an accidental or suicidal manner of death.

L’activateur tissulaire du plasminogène est une sérine protéase initialement découverte dans le compartiment vasculaire et qui joue un rôle prépondérant dans le processus de fibrinolyse. De manière intéressante, le tPA est également présent dans le parenchyme cérébral, où il est notamment exprimé par les neurones. Le tPA est impliqué dans de nombreuses fonctions cérébrales dont la plasticité synaptique, les processus de mémoire et d’apprentissage ainsi que dans la survie et la mort neuronales. Le tPA est capable d’augmenter la signalisation calcique induite par une activation des récepteurs N-Méthyl-D-Aspartate (NMDAR) : un mécanisme à la base de la plasticité synaptique mais également de la mort neuronale excitotoxique. Cependant, il peut également activer les récepteurs du facteur de croissance épidermique (EGFR) pour induire un effet anti-apoptotique sur les neurones. Afin de mieux comprendre les différentes fonctions du tPA sur les neurones, nous nous sommes intéressés à la distribution et au trafic intracellulaire du tPA. Pour cela, nous avons créé un nouvel outil afin d’imager le tPA dans les neurones en temps réel: un plasmide codant pour une protéine fusion, le tPA-HaloTag®.Premièrement, nos résultats montrent que le tPA est présent dans les axones et les dendrites des neurones corticaux matures en culture et qu’il est majoritairement présent dans le compartiment post-synaptique. Cette étude a également permis de voir que le tPA est stocké et libéré par des vésicules d’exocytose VAMP2, qu’il peut être endocyté par des vésicules Rab5, recyclé par des vésicules Rab11 et dégradé par des vésicules Rab7. Deuxièmement, nous avons montré que le tPA est présent dans les mêmes vésicules synaptiques que le facteur neurotrophique issu du cerveau (BDNF) : une neurotrophine importante pour le bon fonctionnement cérébral et dont la maturation dépend de l’activité protéolytique du tPA. Ce travail fournit une meilleure compréhension du rôle et de la distribution du tPA dans les neurones et ouvre de nouvelles voies de recherche dans l’implication de du tPA et du BDNF dans la survie neuronale. / Tissue-type Plasminogen Activator (tPA) is a serine protease, firstly discovered for its fibrinolytic role in the vascular compartment. Interestingly, tPA is also present in the brain parenchyma, being notably expressed by neurons. tPA displays important roles in synaptic plasticity(Danny Baranes et al., 1998; Melchor and Strickland, 2006), learning, memory processes(R Madani et al., 1999; R Pawlak et al., 2002), neuronal survival and death. tPA is able to promote N-Methyl-D-Aspartate Receptors (NMDAR)-induced calcium influx, promoting synaptic plasticity or excitotoxic neuronal death. tPA is also able to activate Epidermal Growth Factor Receptors (EGFR), a mechanism mediating its anti-apoptotic effect. To better understand the different functions of tPA on neurons, we studied the pattern of distribution and trafficking of neuronal tPA. For that, we designed a new tool to image tPA in living neurons: a plasmid encoding for a tPA-HaloTag® fusion protein. We first found that tPA is present in both axons and dendrites of mature cultured cortical neurons and preferentially at the post-synaptic part. Our results also showed that tPA is stored and released by VAMP2 exocytotic vesicles, and can be endocytosed by Rab5 vesicles, recycled by Rab11 vesicles and degraded by Rab7 vesicles. Furthermore, tPA is localized and sorted in the same vesicles than Brain-Derived Neurotrophic Factor (BDNF), one of the most important neurotrophins, Interestingly, BDNF maturation is dependent of tPA proteolytic activity. This work provides a better understanding of the role and distribution of tPA in living neurons and opens new avenues into the involvement of tPA and BDNF in neuronal survival.

Time-restricted eating is a fasting diet where the food intake is restricted to a short, typically eight-hour, window each day. It is associated with health benefits such as weight loss, improved sleep, protection against cognitive disorders, and improved cognitive function. The cognitive effects of time-restricted eating have primarily been explained by the production of ketogenesis – an alternative energy source produced when calories are restricted – and anti-inflammatory cytokines. The gut microbiota is the trillions of microorganisms inhabiting the intestinal tract and has also been associated with improved mental health through communication via the gut-brain axis. This review aims to investigate whether changes in the microbiota may mediate the effect of time-restricted eating on cognitive function. Studies investigating the effect of time-restricted eating on the microbiota were systematically reviewed. The results indicate that time-restricted eating may alter the microbiome composition and increase butyrate-producing bacteria. Butyrate is a short-chain fatty acid associated with the expression of genes involved in neural development and the reduction of neuroinflammation. Limited by the few studies reviewed, the results may indicate a possible link between time-restricted eating and cognitive function via the microbiota, although more research is needed.

Oligodendrocytes are the predominant cell type in white matter and are highly vulnerable to ischemic injury. The role of oligodendrocyte dysfunction in ischemic brain injury is unknown. In this study, we used a 24-amino acid peptide S14G-Humanin (HNG) to examine oligodendrogenesis and neurological functional recovery in a hypoxic/ischemic (H/I) neonatal model. Intraperitoneal HNG pre-treatment decreased infarct volume following H/I injury. Delayed HNG treatment 24 h after H/I injury did not reduce infarct volume but did decrease neurological deficits and brain atrophy. Delayed HNG treatment did not attenuate axonal demyelination at 48 h after H/I injury. However, at 14 d after H/I injury, delayed HNG treatment increased axonal remyelination, the thickness of corpus callosum at the midline, the number of Olig2+/BrdU+ cells, and levels of brain-derived neurotrophic factor (BDNF). Our results suggest that targeting oligodendrogenesis via delayed HNG treatment may represent a promising approach for the treatment of stroke.

As a classic neurotransmitter in the brain, norepinephrine (NE) also is an important modulator to other neuronal systems. Using primary cultures from rat ventral mesencephalon (VM) and dopaminergic cell line MN9D, the present study examined the neuroprotective effects of NE and its effects on the expression of tyrosine hydroxylase (TH). The results showed that NE protected both VM cultures and MN9D cells against 6-hydroxydopamine-caused apoptosis, with possible involvement of adrenal receptors. In addition, treatment with NE upregulated TH protein levels in dose- and time-dependent manner. Further experiments to investigate the potential mechanisms underlying this NE-induced upregulation of TH demonstrated a marked increase in protein levels of the brain-derived neurotrophic factor (BDNF) and the phosphorylated extracellular signal-regulated protein kinase 1 and 2 (pERK1/2) in VM cultures treated with NE. In MN9D cells, a significantly increase of TH and pERK1/2 protein levels were observed after their transfection with BDNF cDNA or exposure to BDNF peptides. Treatment of VM cultures with K252a, an antagonist of the tropomyosin-related kinase B, blocked the upregulatory effects of NE on TH, BDNF and pERK1/2. Administration of MEK1 & MEK2 inhibitors also reversed NE-induced upregulation of TH and pERK1/2. Moreover, ChIP assay showed that treatment with NE or BDNF increased H4 acetylation in the TH promoter. These results suggest that the neuroprotection and modulation of NE on dopaminergic neurons are mediated via BDNF and MAPK/ERK pathways, as well as through epigenetic histone modification, which may have implications for the improvement of therapeutic strategies for Parkinson's disease.

Exercise alone is an efficacious intervention for depression, but few studies have identified the benefits of using exercise to augment other psychosocial treatments. The purpose of the current series of studies was to examine the feasibility, acceptability, efficacy, and potential mechanism of the augmentation of behavioral activation (BA) with exercise. The starting point for this series was a meta-analysis of the strength and reliability of brain-derived neurotrophic factor (BDNF) as a putative mechanism of the mood and cognitive effects of exercise. Evaluating 29 studies, I found: (1) a moderate effect for BDNF increases following acute exercise, (2) a moderate effect for the intensification of this effect following a program of exercise, and (3) a small effect on resting BDNF following a program of exercise. Given these effects, I hypothesized that exercise added to BA would improve mood beyond that for BA combined with a control condition and that changes in BDNF would mediate these effects. In a clinical trial, 32 sedentary, depressed patients received 9 sessions of BA over 12 weeks and were randomized to receive an exercise or control (stretching) augmentation. Assessments of depression, quality of life, distress intolerance, perceived stress, cognition (memory, attention), and amount of exercise were conducted across the treatment period. Results demonstrated strong credibility ratings and completion rates comparable to other exercise interventions. The randomized treatment failed to lead to differential exercise between groups; all participants exercised more over time. Similarly, participants, regardless of condition, significantly improved on all outcome measures over time. BDNF significantly increased following acute exercise. However, the amount of exercise completed over time was not significantly related to changes in BDNF across acute episodes, nor did resting BDNF significantly improve over time. Nonetheless, effect sizes for these changes were in the moderate range, reflecting values for the literature as a whole. Finally, contrary to my hypothesis, BDNF changes were not associated with subsequent improvement in depression symptoms. Results from this trial raise questions whether BA may be a powerful enough intervention to increase exercise, thus explicit exercise prescriptions may not be necessary for patients receiving this intervention.