RESUMO
The neurocardiac circuit is integral to physiological regulation of threat and trauma-related responses. However, few direct investigations of brain-behavior associations with replicable physiological markers of PTSD have been conducted. The current study probed the neurocardiac circuit by examining associations among its core regions in the brain (e.g., insula, hypothalamus) and the periphery (heart rate [HR], high frequency heart rate variability [HF-HRV], and blood pressure [BP]). We sought to characterize these associations and to determine whether there were differences by PTSD status. Participants were N = 315 (64.1 % female) trauma-exposed adults enrolled from emergency departments as part of the prospective AURORA study. Participants completed a deep phenotyping session (e.g., fear conditioning, magnetic resonance imaging) two weeks after emergency department admission. Voxelwise analyses revealed several significant interactions between PTSD severity 8-weeks posttrauma and psychophysiological recordings on hypothalamic connectivity to the prefrontal cortex (PFC), insula, superior temporal sulcus, and temporoparietaloccipital junction. Among those with PTSD, diastolic BP was directly correlated with right insula-hypothalamic connectivity, whereas the reverse was found for those without PTSD. PTSD status moderated the association between systolic BP, HR, and HF-HRV and hypothalamic connectivity in the same direction. While preliminary, our findings may suggest that individuals with higher PTSD severity exhibit compensatory neural mechanisms to down-regulate autonomic imbalance. Additional study is warranted to determine how underlying mechanisms (e.g., inflammation) may disrupt the neurocardiac circuit and increase cardiometabolic disease risk in PTSD.
Assuntos
Pressão Sanguínea , Frequência Cardíaca , Imageamento por Ressonância Magnética , Transtornos de Estresse Pós-Traumáticos , Humanos , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Transtornos de Estresse Pós-Traumáticos/diagnóstico por imagem , Feminino , Masculino , Adulto , Frequência Cardíaca/fisiologia , Pressão Sanguínea/fisiologia , Hipotálamo/fisiopatologia , Hipotálamo/diagnóstico por imagem , Pessoa de Meia-Idade , Adulto Jovem , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/fisiopatologia , Trauma Psicológico/fisiopatologia , Trauma Psicológico/diagnóstico por imagemAssuntos
Diabetes Insípido Nefrogênico , Comportamento de Ingestão de Líquido , Comportamento Alimentar , Fome , Sede , Feminino , Humanos , Masculino , Diabetes Insípido Nefrogênico/complicações , Diabetes Insípido Nefrogênico/fisiopatologia , Fome/fisiologia , Sede/fisiologia , Criança , Hipotálamo/fisiologia , Hipotálamo/fisiopatologia , Animais , Camundongos , Encéfalo/fisiologia , Encéfalo/fisiopatologia , Comportamento de Ingestão de Líquido/fisiologia , Comportamento Alimentar/fisiologia , Comportamento Alimentar/psicologia , Transtorno do Deficit de Atenção com Hiperatividade/etiologia , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Transtornos do Crescimento/etiologia , Transtornos do Crescimento/fisiopatologiaRESUMO
PURPOSE OF REVIEW: Cachexia is a devasting syndrome which impacts a large number of patients with cancer. This review aims to provide a comprehensive overview of the central mechanisms of cancer cachexia. In particular, it focuses on the role of the central nervous system (CNS), the melanocortin system, circulating hormones and molecules which are produced by and act on the CNS and the psychological symptoms of cancer cachexia. RECENT FINDINGS: A growing body of evidence suggests that a central mechanism of action underpins this multi-system disorder. Recent research has focused on the role of neuroinflammation that drives the sickness behaviour seen in cancer cachexia, with emphasis on the role of the hypothalamus. Melanocortin receptor antagonists are showing promise in preclinical studies. There are also new pharmacological developments to overcome the short half-life of ghrelin. GDF-15 has been identified as a core target and trials of compounds that interfere with its signalling or its central receptor are underway. SUMMARY: Understanding the central mechanisms of cancer cachexia is pivotal for enhancing treatment outcomes in patients. While emerging pharmacological interventions targeting these pathways have shown promise, further research is essential.
Assuntos
Caquexia , Grelina , Neoplasias , Caquexia/etiologia , Caquexia/fisiopatologia , Humanos , Neoplasias/complicações , Grelina/metabolismo , Melanocortinas , Fator 15 de Diferenciação de Crescimento , Hipotálamo/fisiopatologia , Sistema Nervoso Central/fisiopatologia , Doenças Neuroinflamatórias/fisiopatologiaRESUMO
OBJECTIVE: To investigate hypothalamic atrophy and its clinical correlates in multiple system atrophy (MSA) in-vivo. BACKGROUND: MSA is characterized by autonomic dysfunction and parkinsonian/cerebellar manifestations. The hypothalamus regulates autonomic and homeostatic functions and is also involved in memory and learning processes. METHODS: 11 MSA, 18 Parkinson's Disease (PD) and 18 Healthy Controls (HC) were included in this study. A validated and automated hypothalamic segmentation tool was applied to 3D-T1-weighted images acquired on a 3T MRI scanner. MSA hypothalamic volumes were compared to those of PD and HC. Furthermore, the association between hypothalamic volumes and scores of autonomic, depressive, sleep and cognitive manifestations were investigated. RESULTS: Posterior hypothalamus volume was reduced in MSA compared to controls (t = 2.105, p = 0.041) and PD (t = 2.055, p = 0.046). Total hypothalamus showed a trend towards a reduction in MSA vs controls (t = 1.676, p = 0.101). Reduced posterior hypothalamus volume correlated with worse MoCA scores in the parkinsonian (MSA + PD) group and in each group separately, but not with autonomic, sleep, or depression scores. CONCLUSIONS: In-vivo structural hypothalamic involvement may be present in MSA. Reduced posterior hypothalamus volume, which includes the mammillary bodies and lateral hypothalamus, is associated with worse cognitive functioning. Larger studies on hypothalamic involvement in MSA and its clinical correlates are needed.
Assuntos
Hipotálamo , Imageamento por Ressonância Magnética , Atrofia de Múltiplos Sistemas , Humanos , Atrofia de Múltiplos Sistemas/diagnóstico por imagem , Atrofia de Múltiplos Sistemas/patologia , Atrofia de Múltiplos Sistemas/fisiopatologia , Masculino , Feminino , Hipotálamo/diagnóstico por imagem , Hipotálamo/patologia , Hipotálamo/fisiopatologia , Idoso , Pessoa de Meia-Idade , Doença de Parkinson/diagnóstico por imagem , Doença de Parkinson/patologia , Doença de Parkinson/fisiopatologiaRESUMO
BACKGROUND: The hypothalamus is central to many hormonal and autonomous nervous system pathways. Emerging evidence indicates that these pathways may be disrupted in schizophrenia and bipolar disorder. Yet, few studies have examined the volumes of hypothalamic subunits in these patient groups. We compared hypothalamic subunit volumes in individuals with psychotic disorders to healthy controls. STUDY DESIGN: We included 344 patients with schizophrenia spectrum disorders (SCZ), 340 patients with bipolar disorders (BPD), and 684 age- and-sex-matched healthy controls (CTR). Total hypothalamus and five hypothalamic subunit volumes were extracted from T1-weighted magnetic resonance imaging (MRI) using an automated Bayesian segmentation method. Regression models, corrected for age, age2, sex, and segmentation-based intracranial volume (sbTIV), were used to examine diagnostic group differences, interactions with sex, and associations with clinical symptoms, antipsychotic medication, antidepressants and mood stabilizers. STUDY RESULTS: SCZ had larger volumes in the left inferior tubular subunit and smaller right anterior-inferior, right anterior-superior, and right posterior hypothalamic subunits compared to CTR. BPD did not differ significantly from CTR for any hypothalamic subunit volume, however, there was a significant sex-by-diagnosis interaction. Analyses stratified by sex showed smaller right hypothalamus and right posterior subunit volumes in male patients, but not female patients, relative to same-sex controls. There was a significant association between BPD currently taking antipsychotic medication and the left inferior tubular subunits volumes. CONCLUSIONS: Our results show regional-specific alterations in hypothalamus subunit volumes in individuals with SCZ, with relevance to HPA-axis dysregulation, circadian rhythm disruption, and cognition impairment.
Assuntos
Transtorno Bipolar , Hipotálamo , Imageamento por Ressonância Magnética , Esquizofrenia , Humanos , Transtorno Bipolar/diagnóstico por imagem , Transtorno Bipolar/fisiopatologia , Transtorno Bipolar/metabolismo , Transtorno Bipolar/tratamento farmacológico , Transtorno Bipolar/patologia , Esquizofrenia/diagnóstico por imagem , Esquizofrenia/fisiopatologia , Esquizofrenia/metabolismo , Esquizofrenia/tratamento farmacológico , Esquizofrenia/patologia , Masculino , Feminino , Adulto , Hipotálamo/diagnóstico por imagem , Hipotálamo/metabolismo , Hipotálamo/fisiopatologia , Pessoa de Meia-Idade , Adulto JovemAssuntos
Craniofaringioma , Neoplasias Hipofisárias , Humanos , Hipotálamo/fisiopatologia , Obesidade , LipídeosRESUMO
A obesidade é definida pelo excesso de gordura corporal acumulada no tecido adiposo quando o indivíduo atinge valores de IMC igual ou superior a 30 Kg/m2. Constitui um dos principais fatores de risco para várias doenças não transmissíveis (DNTs) como por exemplo, diabetes mellitus tipo 2 (DM2), doenças cardiovasculares, hipertensão arterial, acidente vascular cerebral e até mesmo o câncer. Embora a obesidade esteja diretamente relacionada com o consumo calórico excessivo em relação ao gasto energético diário, sua etiologia pode estar associada aos baixos níveis de atividade física, às alterações neuroendócrinas e aos fatores genéticos. Considerando o componente genético, esta pode ser classificada como sindrômicas e estar associada às alterações cromossômicas estruturais ou numéricas, ou como não sindrômica, quando relacionada, principalmente, com os polimorfismos de nucleotídeos simples (SNPs) em alelos que atuam como herança monogênica, ou ainda com a interação vários genes (poligênica multifatorial). Apesar de existirem muitas etiologias diferentes, normalmente a obesidade é tratada a partir da mesma abordagem, desconsiderando a fisiologia que a desencadeou. Dessa forma, o objetivo do presente trabalho foi abordar a obesidade genética não sindrômica por meio a) da descrição breve de perspectiva histórica sobre seu entendimento; b) da exposição dos principais mecanismos moleculares envolvidos com o controle de peso; c) da compilação dos principais genes e SNPs relacionados; d) da definição dos principais genes; e e) da abordagem das principais perspectivas de intervenção.
Obesity is defined as excess body fat accumulated in the adipose tissue when the individual reaches BMI values equal to or greater than 30 kg/m2. It is one of the main risk factors for several non-communicable diseases (NCDs), such as Type 2 Diabetes mellitus (T2D), cardiovascular diseases, high blood pressure, stroke and even cancer. Although obesity is directly related to excessive calorie intake in relation to daily energy expenditure, its etiology may be associated with low levels of physical activity, neuroendocrine changes, and genetic factors. Considering the genetic component, it can be classified as syndromic and be associated with chromosomal or numerical changes, or as non-syndromic and being related mainly to single nucleotide polymorphisms (SNPs) in alleles that act as monogenic inheritance, or with an interaction of several genes (multifactorial polygenic). Although there are many different etiologies, obesity is usually treated using the same approach, disregarding the physiology that triggered it. Thus, the aim of this study was to address non-syndromic genetic obesity through a) a brief description of a historical perspective on its understanding; b) the exposure of the main molecular mechanisms involved in weight control, c) the compilation of the key genes and related SNPs, d) the definition of the key genes and e) the approach of the main intervention representations.
Assuntos
Humanos , Masculino , Feminino , Peso Corporal/genética , Epigenômica , Genes/genética , Obesidade/genética , Índice de Massa Corporal , Expressão Gênica/genética , Polimorfismo de Nucleotídeo Único/genética , Receptor Tipo 4 de Melanocortina/genética , Melanocortinas/genética , Receptores para Leptina/genética , Dioxigenase FTO Dependente de alfa-Cetoglutarato/genética , Hipotálamo/fisiopatologia , Obesidade/fisiopatologiaRESUMO
Although obesity has been a longstanding health crisis, the genetic architecture of the disease remains poorly understood. Genome-wide association studies have identified many genomic loci associated with obesity, with genes being enriched in the brain, particularly in the hypothalamus. This points to the role of the central nervous system (CNS) in predisposition to obesity, and we emphasize here several key genes along the satiety signaling pathway involved in genetic susceptibility. Interest has also risen regarding the chronic, low-grade obesity-associated inflammation, with a growing concern toward inflammation in the hypothalamus as a precursor to obesity. Recent studies have found that genetic variation in inflammatory genes play a role in obesity susceptibility, and we highlight here several key genes. Despite the interest in the genetic variants of these pathways individually, there is a lack of research that investigates the relationship between the two. Understanding the interplay between genetic variation in obesity genes enriched in the CNS and inflammation genes will advance our understanding of obesity etiology and heterogeneity, improve genetic risk prediction analyses, and highlight new drug targets for the treatment of obesity. Additionally, this increased knowledge will assist in physician's ability to develop personalized nutrition and medication strategies for combating the obesity epidemic. Though it often seems to present universally, obesity is a highly individual disease, and there remains a need in the field to develop methods to treat at the individual level.
Assuntos
Variação Genética , Hipotálamo/fisiopatologia , Inflamação , Obesidade/genética , Obesidade/fisiopatologia , Saciação , Animais , Regulação do Apetite , Encéfalo/fisiologia , Predisposição Genética para Doença , Humanos , Inflamação/genética , Herança Multifatorial , Transdução de SinaisRESUMO
Various environmental stressors, such as extreme temperatures (hot and cold), pathogens, predators and insufficient food, can threaten life. Remarkable progress has recently been made in understanding the central circuit mechanisms of physiological responses to such stressors. A hypothalamomedullary neural pathway from the dorsomedial hypothalamus (DMH) to the rostral medullary raphe region (rMR) regulates sympathetic outflows to effector organs for homeostasis. Thermal and infection stress inputs to the preoptic area dynamically alter the DMH â rMR transmission to elicit thermoregulatory, febrile and cardiovascular responses. Psychological stress signalling from a ventromedial prefrontal cortical area to the DMH drives sympathetic and behavioural responses for stress coping, representing a psychosomatic connection from the corticolimbic emotion circuit to the autonomic and somatic motor systems. Under starvation stress, medullary reticular neurons activated by hunger signalling from the hypothalamus suppress thermogenic drive from the rMR for energy saving and prime mastication to promote food intake. This Perspective presents a combined neural network for environmental stress responses, providing insights into the central circuit mechanism for the integrative regulation of systemic organs.
Assuntos
Hipotálamo/fisiologia , Hipotálamo/fisiopatologia , Bulbo/fisiologia , Bulbo/fisiopatologia , Rede Nervosa/fisiologia , Rede Nervosa/fisiopatologia , Estresse Fisiológico , Estresse Psicológico/fisiopatologia , Animais , Regulação da Temperatura Corporal/fisiologia , Transtornos de Estresse por Calor/fisiopatologia , Humanos , Vias Neurais/fisiologiaRESUMO
CONTEXT: About one-third of diabetic patients suffer from neuropathic pain, which is poorly responsive to analgesic therapy and associated with greater autonomic dysfunction. Previous research on diabetic neuropathy mainly links pain and autonomic dysfunction to peripheral nerve degeneration resulting from systemic metabolic disturbances, but maladaptive plasticity in the central pain and autonomic systems following peripheral nerve injury has been relatively ignored. OBJECTIVE: This study aimed to investigate how the brain is affected in painful diabetic neuropathy (PDN), in terms of altered structural connectivity (SC) of the thalamus and hypothalamus that are key regions modulating nociceptive and autonomic responses. METHODS: We recruited 25 PDN and 13 painless (PLDN) diabetic neuropathy patients, and 27 healthy adults as controls. The SC of the thalamus and hypothalamus with limbic regions mediating nociceptive and autonomic responses was assessed using diffusion tractography. RESULTS: The PDN patients had significantly lower thalamic and hypothalamic SC of the right amygdala compared with the PLDN and control groups. In addition, lower thalamic SC of the insula was associated with more severe peripheral nerve degeneration, and lower hypothalamic SC of the anterior cingulate cortex was associated with greater autonomic dysfunction manifested by decreased heart rate variability. CONCLUSION: Our findings indicate that alterations in brain structural connectivity could be a form of maladaptive plasticity after peripheral nerve injury, and also demonstrate a pathophysiological association between disconnection of the limbic circuitry and pain and autonomic dysfunction in diabetes.
Assuntos
Neuropatias Diabéticas/fisiopatologia , Hipotálamo/fisiopatologia , Neuralgia/fisiopatologia , Disautonomias Primárias/fisiopatologia , Tálamo/fisiopatologia , Adaptação Fisiológica , Adulto , Idoso , Sistema Nervoso Autônomo/fisiologia , Conectoma , Imagem de Tensor de Difusão , Feminino , Humanos , Hipotálamo/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiopatologia , Vias Neurais/fisiopatologia , Plasticidade Neuronal/fisiologia , Tálamo/diagnóstico por imagemRESUMO
BACKGROUND: Functional connectivity alterations in the lateral and medial hypothalamic networks have been associated with the development and maintenance of obesity, but the possible impact on the structural properties of these networks remains largely unexplored. Also, obesity-related gut dysbiosis may delineate specific hypothalamic alterations within obese conditions. We aim to assess the effects of obesity, and obesity and gut-dysbiosis on the structural covariance differences in hypothalamic networks, executive functioning, and depressive symptoms. METHODS: Medial (MH) and lateral (LH) hypothalamic structural covariance alterations were identified in 57 subjects with obesity compared to 47 subjects without obesity. Gut dysbiosis in the subjects with obesity was defined by the presence of high (n = 28) and low (n = 29) values in a BMI-associated microbial signature, and posthoc comparisons between these groups were used as a proxy to explore the role of obesity-related gut dysbiosis on the hypothalamic measurements, executive function, and depressive symptoms. RESULTS: Structural covariance alterations between the MH and the striatum, lateral prefrontal, cingulate, insula, and temporal cortices are congruent with previously functional connectivity disruptions in obesity conditions. MH structural covariance decreases encompassed postcentral parietal cortices in the subjects with obesity and gut-dysbiosis, but increases with subcortical nuclei involved in the coding food-related hedonic information in the subjects with obesity without gut-dysbiosis. Alterations for the structural covariance of the LH in the subjects with obesity and gut-dysbiosis encompassed increases with frontolimbic networks, but decreases with the lateral orbitofrontal cortex in the subjects with obesity without gut-dysbiosis. Subjects with obesity and gut dysbiosis showed higher executive dysfunction and depressive symptoms. CONCLUSIONS: Obesity-related gut dysbiosis is linked to specific structural covariance alterations in hypothalamic networks relevant to the integration of somatic-visceral information, and emotion regulation.
Assuntos
Disbiose/complicações , Doenças Hipotalâmicas/etiologia , Vias Neurais/fisiologia , Obesidade/complicações , Obesidade/fisiopatologia , Adulto , Índice de Massa Corporal , Estudos Transversais , Disbiose/fisiopatologia , Feminino , Humanos , Hipotálamo/fisiopatologia , Masculino , Pessoa de Meia-Idade , Vias Neurais/anormalidadesRESUMO
The neuroendocrine system coordinates metabolic and behavioral adaptations to fasting, including reducing energy expenditure, promoting counterregulation, and suppressing satiation and anxiety to engage refeeding. Here, we show that steroid receptor coactivator-2 (SRC-2) in pro-opiomelanocortin (POMC) neurons is a key regulator of all these responses to fasting. POMC-specific deletion of SRC-2 enhances the basal excitability of POMC neurons; mutant mice fail to efficiently suppress energy expenditure during food deprivation. SRC-2 deficiency blunts electric responses of POMC neurons to glucose fluctuations, causing impaired counterregulation. When food becomes available, these mutant mice show insufficient refeeding associated with enhanced satiation and discoordination of anxiety and food-seeking behavior. SRC-2 coactivates Forkhead box protein O1 (FoxO1) to suppress POMC gene expression. POMC-specific deletion of SRC-2 protects mice from weight gain induced by an obesogenic diet feeding and/or FoxO1 overexpression. Collectively, we identify SRC-2 as a key molecule that coordinates multifaceted adaptive responses to food shortage.
Assuntos
Metabolismo Energético , Jejum/metabolismo , Comportamento Alimentar , Hipotálamo/metabolismo , Neurônios/metabolismo , Coativador 2 de Receptor Nuclear/metabolismo , Obesidade/metabolismo , Hipernutrição/metabolismo , Pró-Opiomelanocortina/metabolismo , Animais , Ansiedade/metabolismo , Ansiedade/fisiopatologia , Ansiedade/psicologia , Modelos Animais de Doenças , Jejum/psicologia , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Células HEK293 , Humanos , Hipotálamo/fisiopatologia , Masculino , Camundongos Knockout , Coativador 2 de Receptor Nuclear/genética , Obesidade/genética , Obesidade/fisiopatologia , Obesidade/psicologia , Hipernutrição/genética , Hipernutrição/fisiopatologia , Hipernutrição/psicologia , Pró-Opiomelanocortina/genética , Resposta de Saciedade , Transdução de Sinais , Aumento de PesoRESUMO
Obesity has now reached pandemic proportions and represents a major socioeconomic and health problem in our societies [...].
Assuntos
Hipotálamo/metabolismo , Obesidade/fisiopatologia , Metabolismo Energético , Humanos , Hipotálamo/fisiopatologiaRESUMO
Store-operated calcium entry (SOCE) is pivotal in maintaining intracellular Ca2+ level and cell function; however, its role in obesity development remains largely unknown. Here, we show that the stromal interaction molecule 1 (Stim1), an endoplasmic reticulum (ER) Ca2+ sensor for SOCE, is critically involved in obesity development. Pharmacological blockade of SOCE in the brain, or disruption of Stim1 in hypothalamic agouti-related peptide (AgRP)-producing neurons (ASKO), significantly ameliorates dietary obesity and its associated metabolic disorders. Conversely, constitutive activation of Stim1 in AgRP neurons leads to an obesity-like phenotype. We show that the blockade of SOCE suppresses general translation in neuronal cells via the 2',5'-oligoadenylate synthetase 3 (Oas3)-RNase L signaling. While Oas3 overexpression in AgRP neurons protects mice against dietary obesity, deactivation of RNase L in these neurons significantly abolishes the effect of ASKO. These findings highlight an important role of Stim1 and SOCE in the development of obesity.
Assuntos
Proteína Relacionada com Agouti/metabolismo , Sinalização do Cálcio , Cálcio/metabolismo , Retículo Endoplasmático/metabolismo , Hipotálamo/metabolismo , Neurônios/metabolismo , Obesidade/prevenção & controle , Molécula 1 de Interação Estromal/deficiência , 2',5'-Oligoadenilato Sintetase/metabolismo , Proteína Relacionada com Agouti/genética , Animais , Linhagem Celular Tumoral , Dieta Hiperlipídica , Modelos Animais de Doenças , Endorribonucleases/metabolismo , Células HEK293 , Humanos , Hipotálamo/fisiopatologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Obesidade/genética , Obesidade/metabolismo , Obesidade/fisiopatologia , Molécula 1 de Interação Estromal/genética , Aumento de PesoRESUMO
The hypothalamus has been attributed an important role during the premonitory phase of a migraine attack. Less is known about the role played by the hypothalamus in the interictal period and its relationship with the putative neurocognitive networks previously identified in the pathophysiology of migraine. Our aim was to test whether the hypothalamic microstructure would be altered during the interictal period and whether this co-existed with aberrant connectivity at cortical level. We collected multimodal MRI data from 20 untreated patients with migraine without aura between attacks (MO) and 20 healthy controls (HC) and studied fractional anisotropy, mean (MD), radial (RD), and axial diffusivity of the hypothalamus ROI as a whole from diffusion tensor imaging (DTI). Moreover, we performed an exploratory analysis of the same DTI metrics separately for the anterior and posterior hypothalamic ROIs bilaterally. From resting-state functional MRI, we estimated the Higuchi's fractal dimension (FD), an index of temporal complexity sensible to describe non-periodic patterns characterizing BOLD signature. Finally, we correlated neuroimaging findings with migraine clinical features. In comparison to HC, MO had significantly higher MD, AD, and RD values within the hypothalamus. These findings were confirmed also in the exploratory analysis on the sub-regions of the hypothalamus bilaterally, with the addition of lower FA values on the posterior ROIs. Patients showed higher FD values within the salience network (SN) and the cerebellum, and lower FD values within the primary visual (PV) network compared to HC. We found a positive correlation between cerebellar and SN FD values and severity of migraine. Our findings of hypothalamic abnormalities between migraine attacks may form part of the neuroanatomical substrate that predisposes the onset of the prodromal phase and, therefore, the initiation of an attack. The peculiar fractal dimensionality we found in PV, SN, and cerebellum may be interpreted as an expression of abnormal efficiency demand of brain networks devoted to the integration of sensory, emotional, and cognitive information related to the severity of migraine.
Assuntos
Hipotálamo/patologia , Enxaqueca sem Aura/fisiopatologia , Humanos , Hipotálamo/diagnóstico por imagem , Hipotálamo/fisiopatologia , Imageamento por Ressonância Magnética , Enxaqueca sem Aura/diagnóstico por imagemRESUMO
BACKGROUND/OBJECTIVES: Obesity has been ascribed to corticostriatal regions taking control over homeostatic areas. To test this assumption, we applied an effective connectivity approach to reveal the direction of information flow between brain regions and the valence of connections (excitatory versus inhibitory) as a function of increased BMI and homeostatic state. SUBJECTS/METHODS: Forty-one participants (21 overweight/obese) underwent two resting-state fMRI scans: after overnight fasting (hunger) and following a standardised meal (satiety). We used spectral dynamic causal modelling to unravel hunger and increased BMI-related changes in directed connectivity between cortical, insular, striatal and hypothalamic regions. RESULTS: During hunger, as compared to satiety, we found increased excitation of the ventromedial prefrontal cortex over the ventral striatum and hypothalamus, suggesting enhanced top-down modulation compensating energy depletion. Increased BMI was associated with increased excitation of the anterior insula over the hypothalamus across the hunger and satiety conditions. The interaction of hunger and increased BMI yielded decreased intra-cortical excitation from the dorso-lateral to the ventromedial prefrontal cortex. CONCLUSIONS: Our findings suggest that excess weight and obesity is associated with persistent top-down excitation of the hypothalamus, regardless of homeostatic state, and hunger-related reductions of dorso-lateral to ventromedial prefrontal inputs. These findings are compatible with eating without hunger and reduced self-regulation views of obesity.
Assuntos
Índice de Massa Corporal , Hipotálamo/fisiopatologia , Rede Nervosa/anormalidades , Córtex Pré-Frontal/fisiopatologia , Adulto , Feminino , Humanos , Hipotálamo/anormalidades , Imageamento por Ressonância Magnética/métodos , Imageamento por Ressonância Magnética/estatística & dados numéricos , Masculino , Rede Nervosa/fisiopatologia , Córtex Pré-Frontal/anormalidadesRESUMO
The tuberomamillary nucleus (TMN) is located within the posterior part of the hypothalamus. The histamine neurons in it synthesize histamine by means of the key enzyme histidine decarboxylase (HDC) and from the TMN, innervate a large number of brain areas, such as the cerebral cortex, hippocampus, amygdala as well as the thalamus, hypothalamus, and basal ganglia. Brain histamine is reduced to an inactivated form, tele-methylhistamine (t-MeHA), by histamine N-methyltransferase (HMT). In total, there are four types of histamine receptors (H1-4Rs) in the brain, all of which are G-protein coupled. The histaminergic system controls several basal physiological functions, including the sleep-wake cycle, energy and endocrine homeostasis, sensory and motor functions, and cognitive functions such as attention, learning, and memory. Histaminergic dysfunction may contribute to clinical disorders such as Parkinson's disease, Alzheimer's disease, Huntington's disease, narcolepsy type 1, schizophrenia, Tourette syndrome, and autism spectrum disorder. In the current chapter, we focus on the role of the histaminergic system in these neurological/neuropsychiatric disorders. For each disorder, we first discuss human data, including genetic, postmortem brain, and cerebrospinal fluid studies. Then, we try to interpret the human changes by reviewing related animal studies and end by discussing, if present, recent progress in clinical studies on novel histamine-related therapeutic strategies.
Assuntos
Histamina , Hipotálamo/fisiopatologia , Transtornos Mentais , Doenças do Sistema Nervoso , Animais , Histidina Descarboxilase , Humanos , Receptores HistamínicosRESUMO
BACKGROUND: Intermittent explosive disorder (IED) is a psychiatric disorder characterized by recurrent outbursts of aggressive behavior. Deep brain stimulation (DBS) in the posteromedial nucleus of the hypothalamus (pHyp) is an alternative therapy for extreme cases and shows promising results. Intraoperative microdialysis can help elucidate the neurobiological mechanism of pHyp-DBS. We sought to evaluate efficacy and safety of pHyp-DBS using 8-contact directional leads in patients with refractory IED (rIED) and the accompanying changes in neurotransmitters. METHODS: This was a prospective study in which patients with a diagnosis of rIED were treated with pHyp-DBS for symptom alleviation. Bilateral pHyp-DBS was performed with 8-contact directional electrodes. Follow-up was performed at 3, 6, and 12 months after surgery. RESULTS: Four patients (3 men, mean age 27 ± 2.8 years) were included. All patients were diagnosed with rIED and severe intellectual disability. Two patients had congenital rubella, one had a co-diagnosis of infantile autism, and the fourth presented with drug-resistant epilepsy. There was a marked increase in the levels of gamma-aminobutyric acid and glycine during intraoperative stimulation. The average improvement in aggressive behavior in the last follow-up was 6 points (Δ: 50%, P = 0.003) while also documenting an important improvement of the Short Form Health Survey in all domains except bodily pain. No adverse events associated with pHyp-DBS were observed. CONCLUSIONS: This is the first study to show the safety and beneficial effect of directional lead pHyp-DBS in patients with rIED and to demonstrate the corresponding mechanism of action through increases in gamma-aminobutyric acid and glycine concentration in the pHyp.
Assuntos
Estimulação Encefálica Profunda , Transtornos Disruptivos, de Controle do Impulso e da Conduta/cirurgia , Hipotálamo/cirurgia , Adulto , Feminino , Humanos , Hipotálamo/fisiopatologia , Masculino , Estudos Prospectivos , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND AND AIMS: Serotonergic and dopaminergic systems in the brain are essential for homeostatic and reward-associated regulation of food intake and systemic energy metabolism. It is largely unknown how fasting influences these systems or if such effects are altered in humans with obesity. We therefore aimed to evaluate the effects of fasting on hypothalamic/thalamic serotonin transporter (SERT) and striatal dopamine transporter (DAT) availability in lean subjects and subjects with obesity. METHODS: In this randomized controlled cross-over trial, we assessed the effects of 12 vs 24â¯h of fasting on SERT and DAT availability in the hypothalamus/thalamus and striatum, respectively, using SPECT imaging in 10 lean men and 10 men with obesity. RESULTS: As compared with the 12-h fast, a 24-h fast increased hypothalamic SERT availability in lean men, but not in men with obesity. We observed high inter-individual variation in the effects of fasting on thalamic SERT and striatal DAT, with no differences between lean men and those with obesity. In all subjects, fasting-induced increases in circulating free fatty acid (FFA) concentrations were associated with an increase in hypothalamic SERT availability and a decrease in striatal DAT availability. Multiple regression analysis showed that changes in plasma insulin and FFAs together accounted for 44% of the observed variation in striatal DAT availability. CONCLUSION: Lean men respond to prolonged fasting by increasing hypothalamic SERT availability, whereas this response is absent in men with obesity. Inter-individual differences in the adaptations of the cerebral serotonergic and dopaminergic systems to fasting may, in part, be explained by changes in peripheral metabolic signals of fasting, including FFAs and insulin.
Assuntos
Jejum , Hipotálamo/fisiopatologia , Obesidade/metabolismo , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Idoso , Estudos de Casos e Controles , Corpo Estriado/diagnóstico por imagem , Corpo Estriado/metabolismo , Estudos Cross-Over , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Ácidos Graxos não Esterificados/metabolismo , Humanos , Hipotálamo/diagnóstico por imagem , Hipotálamo/metabolismo , Insulina/metabolismo , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada de Emissão de Fóton ÚnicoRESUMO
Baroreflex sensitivity (BRS) is an important function of the nervous system and essential for maintaining blood pressure levels in the physiological range. In hypertension, BRS is decreased both in man and animals. Although increased sympathetic activity is thought to be the main cause of decreased BRS, hence the development of hypertension, the BRS is regulated by both sympathetic (SNS) and parasympathetic (PNS) nervous system. Here, we analyzed neuropeptide changes in the lateral hypothalamus (LH), which favours the SNS activity, as well as in PNS nuclei in the brainstem of spontaneously hypertensive rats (SHR) and their normotensive controls (Wistar Kyoto rats- WKY). The analyses revealed that in the WKY rats the hypothalamic orexin system, known for its role in sympathetic activation, showed a substantial decrease when animals age. At the same time, however, such a decrease was not observed when hypertension developed in the SHR. In contrast, Neuropeptide FF (NPFF) and Prolactin Releasing Peptide (PrRP) expression in the PNS associated Nucleus Tractus Solitarius (NTS) and Dorsal Motor Nucleus of the Vagus (DMV) diminished substantially, not only after the establishment of hypertension but also before its onset. Therefore, the current results indicate early changes in areas of the central nervous system involved in SNS and PNS control of blood pressure and associated with the development of hypertension.