Efeitos de dois modelos experimentais de dietas hipercalóricas sobre parâmetros comportamentais e biológicos em ratos da linhagem Wistar

O objetivo deste estudo foi investigar os efeitos de dois modelos experimentais de dietas hipercalóricas em comportamentos de ansiedade, processos de aprendizagem e memória e alterações metabólicas. Os animais foram divididos em seis grupos experimentais, de acordo com a condição nutricional. 1) Controle (C); 2) Dieta de Cafeteria (DC); 3) Dieta Hiperlipídica (DH); 4) Controle AIN-93 (C/AIN-93); 5) Dieta de Cafeteria AIN-93 (DC/AIN-93), e 6) Dieta Hiperlipídica AIN-93 (DH/AIN-93). Posteriormente, os grupos foram subdivididos em dois grupos independentes, conforme a tarefa à qual foram submetidos. Pesagens foram realizadas semanalmente até os 98 dias de vida; foram verificados os pesos do fígado, do coração e o peso de tecido adiposo retroperitoneal e epididimal e foram realizadas dosagens de glicose, triglicérides, TGO e TGP no soro e gordura total, colesterol total e triglicérides no fígado. Os testes utilizados: Labirinto em T Elevado (LTE), Caixa Claro/Escuro e Labirinto Aquático de Morris (LAM). Os resultados de peso corporal, os dados comportamentais do LAM, do LTE e os dados de peso dos tecidos extraídos no dia do sacrifício e as análises bioquímicas foram submetidos a uma Análise de Variância (ANOVA). Quando apropriado, foi utilizado o teste de comparações múltiplas de Newman-Keuls (p< 0,05). Os dados comportamentais do teste claro/escuro foram submetidos ao teste t-Student (p< 0,05). Animais tratados com dieta hiperlipídica apresentaram maiores medidas de peso e ganho de peso comparados aos animais controle e dieta de cafeteria, tratados com pellet e com dieta AIN-93. Animais DH1, DC1, DH1 AIN-93, DH2 AIN-93 e DH2 apresentaram maior peso no dia do sacrifício. Animais DH1, DH1 AIN-93, DH2 e DH2 AIN-93 apresentaram maior acúmulo dos tecidos adiposos retroperitoneal e epididimal. Animais DH1 AIN-93 e DC2 AIN-93 apresentaram maiores níveis de glicose. Animais C2, DH2 e DC2 apresentaram maiores níveis de triglicérides. Animais DH1 e C1 apresentaram menores valores de TGO. Animais C2 e C2 AIN-93 apresentaram maiores níveis de TGO. Animais C1, DH1, C2 e DH2 apresentaram maiores níveis de TGP. Animais DH1 AIN-93, DH1, DH2 e DH2 AIN-93 apresentaram maiores valores de gordura total no fígado. Animais DH1 AIN-93 e DH2 apresentaram maiores níveis de colesterol no fígado. Animais DH1, DC1, DH2 e DH2 AIN-93 apresentaram maiores níveis de triglicérides no fígado. Com relação ao consumo alimentar, animais DH apresentaram maior consumo calórico e maior consumo lipídico quando comparados aos animais C e DC, com ração em pellet ou dieta AIN-93. Com relação ao LTE, não foram verificadas diferenças nas esquivas e na fuga. Animais DC1, DH1 e DH1 AIN-93 apresentaram menores níveis de ansiedade verificados a partir dos dados do teste da caixa claro-escuro. Animais DC2 AIN-93 apresentaram pior desempenho em tarefa de memória. Os dados obtidos a partir deste estudo demonstraram que as dietas utilizadas foram capazes de acarretar ganho de peso, acúmulo de tecido adiposo, alterações metabólicas, diminuição da ansiedade nos animais e pior desempenho em uma tarefa de memória em um dos grupos nutricionais.

Participação da conexina 32 na fisiopatogênese da doença hepática gordurosa não alcoólica em camundongos

A doença hepática gordurosa não alcoólica (DHGNA) abrange alterações desde esteatose até esteato-hepatite não alcoólica (EHNA), podendo evoluir para fibrose, cirrose e carcinoma hepatocelular. A DHGNA é considerada a doença hepática mais comum na atualidade e com prevalência mundial alarmante. Esta doença caracteriza-se, basicamente, pela deposição de triglicérides nos hepatócitos, podendo evoluir com inflamação e fibrose, e está intimamente associada com resistência à insulina (RI), diabetes mellitus tipo 2 e obesidade. Os hepatócitos representam as principais células hepáticas e se comunicam através de junções do tipo gap, formadas principalmente por conexina 32 (Cx32). Esta proteína apresenta importante função no controle da homeostase tecidual, regulando processos fisiológicos e tem sido associada como agente protetor na hepatocarcinogênese e outros processos patológicos, porem pouco se sabe sobre sua participação na DHGNA. Sendo assim, o objetivo deste trabalho foi avaliar a participação da Cx32 na fisiopatogênese da DHGNA, utilizando camundongos knockout para Cx32 (Cx32-KO) submetidos a uma dieta hiperlipídica deficiente em colina. Foram analisados dados biométricos, histopatológicos, função hepática, RI, citocinas inflamatórias, adipocinas, estresse oxidativo, peroxidação lipídica e a expressão de genes envolvidos na DHGNA. Os animais Cx32-KO apresentaram maior acumulo de triglicérides hepáticos em relação aos animais selvagens e, consequentemente, maior peso absoluto e relativo do fígado. Adicionalmente, apresentaram maior inflamação hepática demonstrado pela exacerbação da citocina TNF-α e supressão da IL-10, maior dano hepatocelular indicado pelo aumento das enzimas AST e ALT, aumento da peroxidação lipídica e alterações na expressão de genes chaves na fisiopatogênese da DHGNA, como SREBP1c. No entanto, não houve diferença nos marcadores histopatológicos, RI e estresse oxidativo hepático. Por fim, os animais Cx32-KO apresentaram maior produção de leptina e adiponectina no tecido adiposo. Todos esses resultados revelam que a Cx32 pode atuar como um agente protetor ao desenvolvimento da DHGNA, sugerindo seu potencial como novo alvo terapêutico

PGC-1 alfa como regulador inflamatório na esteato-hepatite não-alcoólica

A doença hepática gordurosa não-alcoólica (NAFLD, do inglês) é a manifestação clínica hepática da síndrome metabólica, cuja incidência aumenta consideravelmente em todo o mundo. A NAFLD pode progredir para um estado de esteatohepatite não-alcoólica (NASH, do inglês), caracterizado por inflamação hepatocelular, com ou sem fibrose. Dados na literatura mostram que o coativador-1 alfa do receptor ativado por proliferadores de peroxissoma gama (PGC-1alfa), além de estar envolvido em diversos processos metabólicos, representa uma estratégia terapêutica promissora na modulação da inflamação. Neste projeto investigamos as alterações inflamatórias no fígado induzida por dieta hiperlipídica e o papel do PGC-1alfa nesse processo. Camundongos C57black/6 receberam dieta hiperlipídica contendo 30% de gordura por 10 semanas. O peso dos animais foi avaliado semanalmente. Após a eutanásia, o tecido adiposo intra-abdominal (retroperitoneal e periepididimal) foi coletado e pesado. Analisamos o perfil glicêmico e lipídico sérico e expressão de genes envolvidos no metabolismo glicêmico e lipídico. Avaliou-se também o aspecto histológico e a inflamação do tecido hepático por quantificação das citocinas IL-6, TNF-alfa e IL-1beta. A dieta rica em gordura conduziu a um aumento dos depósitos de gordura intra-abdominal, hiperglicemia e hiperlipidemia. Os animais também apresentavam esteatohepatite, com aumento de citocinas pró-inflamatórias e diminuição na expressão de PGC-1alfa no tecido hepático. O envolvimento do PGC-1alfa na produção de mediadores inflamatórios por hepatócitos foi avaliado em células HepG2 utilizando RNA de interferência (RNAi). O knockdown da expressão de PGC-1alfa causou aumento na expressão e liberação de IL-6 em hepatócitos via aumento na fosforilação de IkBalfa e consequente ativação do NFkB. Portanto, nossos dados mostram que o PGC-1alfa inibe a produção de mediadores inflamatórios (IL-6) em hepatócitos, e fornecem novas evidências das conexões existentes entre as vias metabólicas e imunes

Avaliação da composição corporal e do estado nutricional em doentes com neoplasias gastrointestinais : bioimpedância elétrica e tomografia axial computorizada, que correlação?

Tese de mestrado, Nutrição Clínica, Faculdade de Medicina, Universidade de Lisboa, 2015

Handbook of physiology : a critical, comprehensive presentation of physiological knowledge and concepts. /

Editors vary.

Association between in-utero exposure to diesel exhaust and N-acetyl-cysteine supplementation in hyperlipidemic pregnant mice and development of atherosclerosis at multiple vascular sites in the offspring

Thesis (Master's)--University of Washington, 2016-06

The Effect of Fructose vs. Glucose Beverages on Low-Grade Systemic Inflammation

Thesis (Ph.D.)--University of Washington, 2016-04

Physical activity, exercise, and inflammatory markers in older adults: Findings from the health, aging and body composition study

OBJECTIVES: To examine the association between physical activity and inflammatory markers, with consideration for body fatness and antioxidant use. DESIGN: Cross-sectional study, using baseline data from the Health, Aging and Body Composition Study. SETTING: Metropolitan areas surrounding Pittsburgh, Pennsylvania, and Memphis, Tennessee. PARTICIPANTS: Black and white, well-functioning men and women (N=3,075), aged 70 to 79. MEASUREMENTS: Interviewer-administered questionnaires of previous-week household, walking, exercise, and occupational/volunteer physical activities. Analysis of covariance was used to examine the association between activity level and serum C-reactive protein (CRP), interleukin-6 (IL-6), and plasma tumor necrosis factor alpha (TNFalpha) with covariate adjustment. Antioxidant supplement use (multivitamin, vitamins E or C, beta carotene) was evaluated as an effect modifier of the association. RESULTS: Higher levels of exercise were associated with lower levels of CRP (P

Fibroblast growth factor 1: A key regulator of human adipogenesis

Obesity, with its related problems, is recognized as the fastest growing disease epidemic facing the world, yet we still have limited insight into the regulation of adipose tissue mass in humans. We have previously shown that adipose-derived microvascular endothelial cells (MVECs) secrete a factor(s) that increases proliferation of human preadipocytes. We now demonstrate that coculture of human preadipocytes with MVECs significantly increases preadipocyte differentiation, evidenced by dramatically increased triacylglycerol accumulation and glycerol-3-phosphate dehydrogenase activity compared with controls. Subsequent analysis identified fibroblast growth factor (FGF)-1 as an adipogenic factor produced by MVECs. Expression of FGF-1 was demonstrated in MVECs but not in preadipocytes, while preadipocytes were shown to express FGF receptors 1-4. The proliferative effect of MVECs on human preadipocytes was blocked using a neutralizing antibody specific for FGF-1. Pharmacological inhibition of FGF-1 signaling at multiple steps inhibits preadipocyte replication and differentiation, supporting the key adipogenic role of FGF-1. We also show that 3T3-L1 cells, a highly efficient murine model of adipogenesis, express FGF-1 and, unlike human preadipocytes, display no increased differentiation potential in response to exogenous FGF-1. Conversely, FGF-1-treated human preadipocytes proliferate rapidly and differentiate with high efficiency in a manner characteristic of 3T3-L1 cells. We therefore suggest that FGF-1 is a key human adipogenic factor, and these data expand our understanding of human fat tissue growth and have significant potential for development of novel therapeutic strategies in the prevention and management of human obesity.

The effect of hormone replacement therapy and/or exercise on skeletal muscle attenuation in postmenopausal women: a yearlong intervention

Hormone replacement therapy (HRT) has been reported to exert a positive effect on preserving muscle strength following the menopause, however, the mechanism of action remains unclear. We examined whether the mechanism involved preservation of muscle composition as determined by skeletal muscle attenuation. Eighty women aged 50-57 years were randomly assigned to either: HRT, exercise (Ex), HRT + exercise (ExHRT), and control (Co) for 1 year. The study was double-blinded with subjects receiving oestradiol and norethisterone acetate (Kliogest) or placebo. Exercise included progressive high-impact training for the lower limbs. Skeletal muscle attenuation in Hounsfield units (HU) was determined by computed tomography of the mid-thigh. Areas examined were the quadriceps compartment (includes intermuscular adipose tissue), quadriceps muscles, the posterior compartment and posterior muscles. Muscle performance was determined by knee extensor strength, vertical jump height, and running speed over 20 m. Fifty-one women completed the intervention. Vertical jump height and running speed improved in the HRT and ExHRT groups compared with Co (interaction, P < 0.01). For both the quadriceps compartment and quadriceps muscles, HU significantly increased (interaction, P <= 0.005) for HRT, Ex, and ExHRT compared with Co. For the posterior compartment, HU for the HRT and ExHRT were significantly increased compared with Co, while for posterior muscles, ExHRT was significantly greater than Co. Although the effects were modest, the results indicate that HRT, either alone or combined with exercise, may play a role in preserving/improving skeletal muscle attenuation in early postmenopausal women and thereby exert a positive effect on muscle performance.

Myocardial and vascular dysfunction and exercise capacity in the metabolic syndrome

The metabolic syndrome (MS) is associated with cardiovascular risk exceeding that expected from atherosclerotic risk factors, but the mechanism of this association is unclear. We sought to determine the effects of the MS on myocardial and vascular function and cardiorespiratory fitness in 393 subjects with significant risk factors but no cardiovascular disease and negative stress echocardiographic findings. Myocardial function was assessed by global strain rate, strain, and regional systolic velocity (s(m)) and diastolic velocity (e(m)) using tissue Doppler imaging. Arterial compliance was assessed using the pulse pressure method, involving simultaneous radial applanation tonometry and echocardiographic measurement of stroke volume. Exercise capacity was measured by expired gas analysis. Significant and incremental variations in left ventricular systolic (s(m), global strain, and strain rate) and diastolic (e(m)) function were found according to the number of components of MS (p <0.001). MS contributed to reduced systolic and diastolic function even in those without left ventricular hypertrophy (p <0.01). A similar dose-response association was present between the number of components of the MS and exercise capacity (p <0.001) and arterial compliance. The global strain rate and em were independent predictors of exercise capacity. In conclusion, subclinical left ventricular dysfunction corresponded to the degree of metabolic burden, and these myocardial changes were associated with reduced cardiorespiratory fitness.' Subjects with MS who also have subclinical myocardial abnormalities and reduced cardiorespiratory fitness may have a higher risk of cardiovascular disease events and heart failure. (C) 2005 Elsevier Inc. All rights reserved.

Hypothalamic control of bone formation: Distinct actions of leptin and Y2 receptor pathways

Leptin and Y2 receptors on hypothalamic NPY neurons mediate leptin effects on energy homeostasis; however, their interaction in modulating osteoblast activity is not established. Here, direct testing of this possibility indicates distinct mechanisms of action for leptin anti-osteogenic and Y2(-/-) anabolic pathways in modulating bone formation. Introduction: Central enhancement of bone formation by hypothalamic neurons is observed in leptin-deficient oblob and Y2 receptor null mice. Similar elevation in central neuropeptide Y (NPY) expression and effects on osteoblast activity in these two models suggest a shared pathway between leptin and Y2 receptors in the central control of bone physiology. The aim of this study was to test whether the leptin and Y2 receptor pathways regulate bone by the same or distinct mechanisms. Materials and Methods: The interaction of concomitant leptin and Y2 receptor deficiency in controlling bone was examined in Y2(-/-) oblob double mutant mice, to determine whether leptin and Y2 receptor deficiency have additive effects. Interaction between leptin excess and Y2 receptor deletion was examined using recombinant adeno-associated viral vector overproduction of NPY (AAV-NPY) to produce weight gain and thus leptin excess in adult Y2(-/-) mice. Cancellous bone volume and bone cell function were assessed. Results: Osteoblast activity was comparably elevated in oblob, Y2(-/-), and Y2(-/-) oblob mice. However, greater bone resorption in oblob and Y2(-/-) oblob mice reduced cancellous bone volume compared with Y2(-/-). Both wildtype and Y2(-/-) AAV-NPY mice exhibited marked elevation of white adipose tissue accumulation and hence leptin expression, thereby reducing osteoblast activity. Despite this anti-osteogenic leptin effect in the obese AAV-NPY model, osteoblast activity in Y2(-/-) AAV-NPY mice remained significantly greater than in wildtype AAV-NPY mice. Conclusions: This study suggests that NPY is not a key regulator of the leptin-dependent osteoblast activity, because both the leptin-deficient stimulation of bone formation and the excess leptin inhibition of bone formation can occur in the presence of high hypothalamic NPY. The Y2(-/-) pathway acts consistently to stimulate bone formation; in contrast, leptin continues to suppress bone formation as circulating levels increase. As a result, they act increasingly in opposition as obesity becomes more marked. Thus, in the absence of leptin, the cancellous bone response to loss of Y2 receptor and leptin activity can not be distinguished. However, as leptin levels increase to physiological levels, distinct signaling pathways are revealed.

Cholesterol-induced caveolin targeting to lipid droplets in adipocytes: A role for caveolar endocytosis

We have investigated the targeting of caveolin to lipid bodies in adipocytes that express high levels of caveolins and contain well-developed lipid droplets. We observed that the lipid droplets isolated from adipocytes of caveolin-1 knock out mice contained dramatically reduced levels of cholesterol, indicating that caveolin is required for maintaining the cholesterol content of this organelle. Analysis of caveolin distribution by cell fractionation and fluorescent light microscopy in 3T3-L1 adipocytes indicated that addition of cholesterol rapidly stimulated translocation of caveolin to lipid droplets. The cholesterol-induced trafficking of caveolins to lipid droplets was shown to be dynamin- and protein kinase C (PKC)-dependent and modulated by src tyrosine kinase activation, suggesting a role for caveolar endocytosis in this novel trafficking pathway. Consistent with this, caveolae budding was stimulated by cholesterol addition. The present data identify lipid droplets as potential target organelles for caveolar endocytosis and demonstrate a role for caveolin-1 in the maintenance of free cholesterol levels in adipocyte lipid droplets.

Clinically active Crohn's disease in the presence of a low C-reactive protein

Objective. Clinical interest in C-reactive protein (CRP) - a component of the innate immune system - has focused mainly on its worth as an indicator of disease activity. There has been a resurgence of interest in CRP in the Crohn's disease ( CD) literature because several trials of new treatments for active CD have been characterized by both a large proportion of patients with low CRP ( < 10 mg/l) at entry to the trials and by a negative therapeutic outcome. It is therefore of interest to study the clinical characteristics of patients who are thought to have at the same time both active CD and a low CRP. Material and methods. Patients were prospectively recruited as part of the Brisbane IBD clinical and research programme. Subjects were included in the low CRP group only if there were complete datasets for CRP on all occasions of active CD, and CRP was < 10 mg/l. Active disease was defined as CD activity index (CDAI) > 200. The low CRP group was compared with patients in the raised CRP group for a range of clinical variables as well as the major NOD2 variants. Results. There were data sets for 223 CD patients, with a mean disease duration of 12 years. Of these, 22 patients fulfilled the criteria for low CRP. The low CRP group ( group 1) showed significant differences for disease site (p < 0.01) and for BMI (p = 0.006) compared to the raised CRP group ( group 2). Specifically, group 1 had a predominance of pure ileal disease (95% versus 53%) and lack of pure colonic disease (0% versus 24%) compared to group 2, and their BMI was significantly lower (20.3 kg/m(2) versus 25.0 kg/m(2)). Groups 1 and 2 did not differ with respect to Vienna behaviour at diagnosis, smoking, appendicectomy, extra-intestinal manifestations of CD, or NOD2 SNP variants. There was a trend for low CRP patients with previous ileal resection to evolve to a stricturing phenotype. Fat wrapping was noted in 11/13 (85%) of low CRP patients undergoing ileal resections. Conclusions. Patients with CD and a persistently low CRP in the face of active disease were characterized by an almost exclusive ileal disease distribution and a low BMI, compared to those with a raised CRP. These patients had a similar frequency and distribution of NOD2/CARD15 variants. Stricturing ( v inflammatory or penetrating) behaviour may explain some low CRP. Despite the abnormally low BMI, fat wrapping was noted in the majority of low CRP patients undergoing ileal resection.

Lipid droplets: a unified view of a dynamic organelle

Lipid droplets form the main lipid store in eukaryotic cells. Although all cells seem to be able to generate lipid droplets, their biogenesis, regulatory mechanisms and interactions with other organelles remain largely elusive. In this article, we outline some of the recent developments in lipid droplet cell biology. We show the mobile and dynamic nature of this organelle, and advocate the adoption of a unified nomenclature to consolidate terminology in this emerging field.