Thais Ortiz Hammes

SIRT1 Transcription Is Decreased in Visceral Adipose Tissue of Morbidly Obese Patients with Severe Hepatic Steatosis

BackgroundVisceral adipose tissue is known to release greater amounts of adipokines and free fatty acids into the portal vein, being one of the most predictive factors of nonalcoholic fatty liver disease (NAFLD). Our study has the purpose to evaluate sirtuin 1 (SIRT1), adiponectin, Forkhead/winged helix (FOXO1), peroxisome proliferator-activated receptor (PPAR)γ1–3, and PPARβ/δ mRNA expression in morbidly obese patients in three different lipid depots: visceral (VAT), subcutaneous (SAT), and retroperitoneal (RAT). Recent studies suggest that SIRT1, a NAD+-dependent deacetylase, protects rats from NAFLD.MethodsWe divided the patients in two groups: those with slight or moderate steatosis (hepatic steatosis, HS) and other comprising individuals with severe steatosis associated or not with necroinflammation and fibrosis (severe hepatic steatosis, SHS). The adipose tissue depots were obtained during bariatric surgery. Total RNAs were extracted using TRIzol. The amount of genes of interest was determined by quantitative real-time polymerase chain reaction.ResultsWhen comparing the two groups of patients, a decrease in SIRT1 was observed in VAT of morbidly obese patients in SHS group (p = 0.006). The mRNA expression of the other genes showed no differences in VAT. No difference was found either in SAT or in RAT for all genes in the study. In addition, the homeostasis model assessment for insulin resistance (HOMA-IR) value was higher in SHS group compared to HS (p = 0.006). Also, our results show that the mRNA expression of SIRT1 and the value of HOMA-IR were positively correlated in VAT of SHS patients (r = 0.654; p = 0.048).ConclusionsDownregulation of SIRT1 mRNA expression in VAT of SHS could be possible impairing mitochondria biogenesis and fatty acid oxidation, promoting severe steatosis in obese patients. Our results provide a possible proof of SIRT1 protective potential in VAT against NAFLD in humans.

Resveratrol Upregulated SIRT1, FOXO1, and Adiponectin and Downregulated PPARγ1–3 mRNA Expression in Human Visceral Adipocytes

BackgroundThe SIRT1 enzyme is involved in adipose tissue (AT) lipolysis. FOXO1 is a protein that plays a significant role in regulating metabolism. Adiponectin is an adipokine, secreted by the AT, which has been considered to have an antiobesity function. PPARγ is one of the key actors in adipocytes differentiation. This study was undertaken to investigate whether resveratrol can regulate SIRT1, FOXO1, adiponectin, PPARγ1–3, and PPARβ/δ in human AT.MethodsThe effects of resveratrol were analyzed in freshly isolated adipocytes prepared from visceral fat tissue samples obtained during bariatric surgery. Genes messenger ribonucleic acid (mRNA) levels were determined by qRT-PCR.ResultsOurs results show that resveratrol modulates the studied genes, increasing SIRT1 (p = 0.021), FOXO1 (p = 0.001), and adiponectin (p = 0.025) mRNA expression and decreasing PPARγ1–3 (p = 0.003) mRNA in human visceral adipocytes.ConclusionsResveratrol, in vitro and at low concentration, modulates genes that are related to lipid metabolism, possibly preventing metabolic disease in human visceral adipose tissue (VAT).

Blood collection for biochemical analysis in adult zebrafish.

The zebrafish has been used as an animal model for studies of several human diseases. It can serve as a powerful preclinical platform for studies of molecular events and therapeutic strategies as well as for evaluating the physiological mechanisms of some pathologies. There are relatively few publications related to adult zebrafish physiology of organs and systems, which may lead researchers to infer that the basic techniques needed to allow the exploration of zebrafish systems are lacking. Hematologic biochemical values of zebrafish were first reported in 2003 by Murtha and colleagues who employed a blood collection technique first described by Jagadeeswaran and colleagues in 1999. Briefly, blood was collected via a micropipette tip through a lateral incision, approximately 0.3 cm in length, in the region of the dorsal aorta. Because of the minute dimensions involved, this is a high-precision technique requiring a highly skilled practitioner. The same technique was used by the same group in another publication in that same year. In 2010, Eames and colleagues assessed whole blood glucose levels in zebrafish. They gained access to the blood by performing decapitations with scissors and then inserting a heparinized microcapillary collection tube into the pectoral articulation. They mention difficulties with hemolysis that were solved with an appropriate storage temperature based on the work Kilpatrick et al. When attempting to use Jagadeeswarans technique in our laboratory, we found that it was difficult to make the incision in precisely the right place as not to allow a significant amount of blood to be lost before collection could be started. Recently, Gupta et al. described how to dissect adult zebrafish organs, Kinkle et al. described how to perform intraperitoneal injections, and Pugach et al. described how to perform retro-orbital injections. However, more work is needed to more fully explore basic techniques for research in zebrafish. The small size of zebrafish presents challenges for researchers using it as an experimental model. Furthermore, given this smallness of scale, it is important that simple techniques are developed to enable researchers to explore the advantages of the zebrafish model.

Parallel Down-Regulation of FOXO1, PPARγ and Adiponectin mRNA Expression in Visceral Adipose Tissue of Class III Obese Individuals

Objective: Adipose tissue is responsible for secretion of several cytokines that mediate systemic effects on obesity and insulin resistance. Subcutaneous abdominal adipose tissue (SAT) and visceral adipose tissue (VAT) are metabolically different and have differences in their gene expression profile. Our study evaluated the expression of adiponectin, FOXO1, PPARγ, and SIRT1 in VAT and SAT of non-obese and class III obese subjects. Methods: The adipose tissue samples were obtained by surgery. Reverse transcripts of studied genes were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Results: Comparing the different lipid depots, adiponectin expression was lower only in VAT of obese individuals (p = 0.043); FOXO1 and PPARγ levels were decreased in VAT of both groups. When non-obese and obese were compared, only adiponectin expression was lower in SAT and in VAT of obese subjects (p = 0.004 and p = 0.002, respectively). No difference was found with regard to SIRT1 levels in VAT or SAT in both groups. FOXO1 expression in SAT of obese subjects had a negative correlation with age (r = –0.683; p = 0.029) and triglyceride serum levels (r = –0.794; p = 0.006). Conclusion: The decrease mRNA expression of this genes in VAT, responsible for central adiposity, may be associated with an increased risk of obesity and co-morbidities.

Impairment of short term memory in rats with hepatic encephalopathy due to bile duct ligation

Hepatic encephalopathy (HE) arises from acute or chronic liver diseases and leads to cognitive deficits. Different animal models for the study of HE have demonstrated learning and memory impairment and a number of neurotransmitter systems have been proposed to be involved in this. Recently, it was described that bile duct-ligated (BDL) rats exhibited altered spatio-temporal locomotor and exploratory activities and biosynthesis of neurotransmitter GABA in brain cortices. Therefore, the aim of this study was to evaluate cognition in the same animal model. Male adult Wistar rats underwent common bile duct ligation (BDL rats) or manipulation of common bile duct without ligation (control rats). Six weeks after surgery, control and BDL rats underwent object recognition behavioral task. The BDL rats developed chronic liver failure and exhibited a decreased discrimination index for short term memory (STM) when compared to the control group. There was no difference in long term memory (LTM) as well as in total time of exploration in the training, STM and LTM sessions between the BDL and control rats. Therefore, the BDL rats demonstrated impaired STM for recognition memory, which was not due to decreased exploration.

Baixas concentrações plasmáticas de zinco em pacientes pediátricos com cirrose

OBJETIVO: Determinar a concentracao plasmatica de zinco em criancas e adolescentes cirroticos e investigar a associacao entre esses resultados e a ingestao dietetica de zinco, os dados antropometricos e a gravidade da doenca hepatica. METODOS: As concentracoes plasmaticas de zinco foram avaliadas por espectrofotometria de absorcao atomica em 30 criancas e adolescentes com cirrose (105,0±60,0 meses; 22 meninas) e 27 higidas e sem doenca hepatica (122,3±47,3 meses, 14 meninas). Os dados relacionados ao zinco dietetico foram avaliados por registro de ingestao alimentar de 3 dias. A antropometria incluiu peso, altura, espessura da dobra cutânea, circunferencia braquial e area muscular do braco. A gravidade da doenca hepatica foi classificada de acordo com os criterios de Child-Pugh, MELD e PELD. RESULTADOS: As concentracoes plasmaticas de zinco dos individuos controles e dos pacientes foram 105,69±19,46 e 75,44±24,45 μg/dL, respectivamente (p < 0,001). Nenhuma associacao foi encontrada entre os indices antropometricos, a ingestao dietetica e o zinco plasmatico. Houve diferenca estatistica nas concentracoes de zinco plasmatico entre pacientes Child-Pugh B+C e controles (p < 0,001), e com relacao ao PELD, entre pacientes abaixo e acima do ponto de corte 15 (p = 0,002). CONCLUSAO: A prevalencia de hipozincemia foi de 43% para pacientes com cirrose. A baixa concentracao plasmatica de zinco foi associada com a doenca hepatica grave; entretanto, a hipozincemia esteve presente mesmo em pacientes Child-Pugh A. Portanto, a suplementacao de zinco deve ser considerada para os pacientes pediatricos cirroticos.

Low plasma zinc concentrations in pediatric patients with cirrhosis.

OBJECTIVE To determine plasma zinc concentrations in children and adolescents with cirrhosis and to investigate the association between these results and dietary zinc intake, anthropometric data, and severity of liver disease. METHODS Plasma zinc concentration was assessed by atomic absorption spectrophotometry in 30 children and adolescents with cirrhosis (105.0+/-60.0 months; 22 girls) and 27 without liver disease (122.3+/-47.3 months, 14 girls). Dietary zinc data were evaluated by 3-day food intake records. Anthropometry measures included height, weight, skinfold thickness, brachial circumference, and upper arm muscle size. Severity of liver disease was classified according to the Child-Pugh, MELD, and PELD criteria. RESULTS The mean (+/- standard deviation) plasma zinc concentrations in control subjects and patients were 105.69+/-19.46 and 75.44+/-24.45 microg/dL, respectively (p < 0.001). No associations were found between anthropometric measures, dietary zinc intake, and plasma zinc concentration. There was statistical difference related to plasma zinc concentrations between Child-Pugh B + C patients and control subjects (p < 0.001), and concerning PELD, between patients below the cutoff score of 15 and those above (p = 0.002). CONCLUSIONS The prevalence of hypozincemia was 43% for patients with cirrhosis. Although low plasma zinc concentration was associated with more severe liver disease, it was present even in some Child-Pugh A patients. Therefore, zinc supplementation should be considered for cirrhotic children.

Experimental model of hepatic steatosis by fructose in adult zebrafish: a pilot study

Introduction: The consumption of fructose has been questioned, since its increase has led to an associated increase in steatosis caused by nonalcoholic fatty liver disease. Despite the advantages presented by the zebrafish as an animal model, at present there are no models of steatosis by fructose in adult zebrafish. The aim of this study is to establish a model of hepatic steatosis by fructose in adult zebrafish. Methods: Firstly, adult zebrafish were daily exposed to 4% or 6% fructose. Then, animals were exposed to 6% fructose every 2 days. The hepatic lipid accumulation was analyzed by Nile Red and Oil Red O staining. Results: The daily exposure to 6% fructose showed increased accumulation of hepatic lipids when compared to 4% and control groups, but the same concentration showed no difference when the exposure happened every 2 days. Conclusion: We can suggest the daily exposure to a concentration of 6% fructose can be considered as a new experimental model of adult zebrafish. Keywords: Fatty liver; fructose; zebrafish

Microbiota e barreira intestinal: implicações para obesidade

A epidemia da obesidade e considerada um importante problema de saude publica na sociedade ocidental, pois ela relaciona-se a comorbidades como sindrome metabolica, diabetes mellitus e hipertensao. A microbiota intestinal pode contribuir para o desenvolvimento da obesidade atraves do aumento da extracao energetica dos componentes da dieta, da lipogenese, da permeabilidade intestinal e da endotoxemia, mediada especialmente pelos lipopolissacarideos. Estudos tem demonstrado diferencas na composicao da microbiota intestinal entre individuos obesos e magros. Ao que parece, o aumento na proporcao de Firmicutes em relacao a Bacteroidetes parece estar presente na obesidade, podendo ser alterada a medida que ocorre perda de peso. Assim, o objetivo deste estudo e revisar a literatura acerca dos mecanismos que relacionam a microbiota e a barreira intestinal ao desenvolvimento ou agravamento da obesidade. Palavras-chave: Obesidade; microbioma gastrointestinal; microbiota; permeabilidade intestinal