Admar Costa de Oliveira

Low doses of insulin-like growth factor-I improve nitrogen retention and food efficiency in rats with early cirrhosis

BACKGROUND/AIMS In order to ascertain whether malnutrition is an early-onset feature of liver cirrhosis and whether the anabolic hormone insulin-like growth factor I (IGF-I) could be useful in the treatment of this complication, we analyzed the nutritional alterations present in rats with early-stage liver cirrhosis and the effects of IGF-I on nutritional parameters in these animals. METHODS After a 24 h fast, a 15N-enriched diet was administered for 5 days to normal control rats and to cirrhotic rats receiving subcutaneous injections of vehicle (Group 1) or IGF-I, 2 micrograms.100 g bw-1.day-1, (Group 2) during the 5 experimental days. 15N, a stable N isotope, was measured in biological samples by mass spectrometry. RESULTS Compared with control rats, Group 1 animals showed significant reductions in N intake and food efficiency (p < 0.05, both). In addition, the weight of the gastrocnemius muscle, its total N content and the dietary N content of this muscle were significantly lower in Group 1 than in control animals (p < 0.05, all). In rats from Group 2, mean values of N intake, food efficiency, gastrocnemius N content and the amount of dietary N incorporated into this muscle were similar to those in control rats, and (with the exception of gastrocnemius N total content) significantly higher than those in non-treated cirrhotic rats (p < 0.05, all). CONCLUSIONS A variety of nutritional disturbances were detected in rats from the early stages of liver cirrhosis. Low doses of IGF-I were found to reverse most of these changes. These results stimulate further studies to determine whether IGF-I might be useful in the correction of the malnutrition present in patients with liver cirrhosis.

Os efeitos do ácido linoléico conjugado no metabolismo animal: avanço das pesquisas e perspectivas para o futuro

This systematic review without date restrictions is about the physiological effects of conjugated linoleic acid on regression of carcinogenesis, oxidative stress, glucose and lipid metabolism and change in body composition. The objective was to establish the historical aspect of research advances regarding conjugated linoleic acid, considering original articles reporting work on animals, cell cultures and humans. Regarding the researches on the anticarcinogenic effect of conjugated linoleic acid, innumerous evidences were found in this respect, especially in the regression of mammary and colon tumors induced by both isomers which act distinctively. The researchers devoted considerable effort to reinvestigate the antioxidant properties of conjugated linoleic acid. Although the antioxidant properties have been investigated, pro-oxidant effect has been identified leading to oxidative stress in humans. Few studies demonstrated significant beneficial effects of conjugated linoleic acid on the metabolism of lipids and glucose and on the reduction of body fat, especially in humans. Studies with adverse effects were also identified. There is strong indication that the action of this conjugated fatty acid on a class of transition factors - the peroxisome proliferator-activated receptor - and on the consequent modulation of gene expression can be the fundamental explanation of its physiological effects. The most recent studies reinforce the nutrigenomic concept, that is, the modulation of gene expression induced by compounds present in the foods consumed by humans. This current scenario stimulates the scientific community to seek a consensus on the effects of conjugated linoleic acid in humans, since it is naturally found in some foods; when these foods are consumed regularly and in appropriate amounts, they could help prevent and control innumerous chronic diseases.

A suplementação com ácido linoléico conjugado reduziu a gordura corporal em ratos Wistar

O acido linoleico conjugado, um conjunto de isomeros geometricos e de posicao do acido linoleico, vem sendo muito estudado devido ao seu efeito sobre a composicao corporal, promovendo reducao da massa gorda. O objetivo deste trabalho foi avaliar o efeito da suplementacao com acido linoleico conjugado sobre a composicao corporal de ratos Wistar saudaveis em crescimento. Um total de 40 ratos, divididos em quatro grupos, foram suplementados diariamente durante tres semanas com AdvantEdge® acido linoleico conjugado (EASTM) nas concentracoes 1,0%, 2,0% e 4,0% sobre o consumo diario de dieta, constituindo, respectivamente, os grupos AE1, AE2 e AE4, e com acido linoleico na concentracao de 2% sobre o consumo diario de dieta, constituindo o grupo-controle. Os animais foram suplementados por meio de entubacao orogastrica. Para a avaliacao da composicao corporal centesimal foi removido o conteudo intestinal para obtencao da carcaca vazia. Em seguida, a carcaca foi congelada em nitrogenio liquido, fatiada, liofilizada, moida e armazenada a -25°C, ate o momento das determinacoes de umidade, cinzas, proteina bruta e gordura. O grupo AE1 apresentou maior consumo de dieta e ganho de peso, mas nao diferiu quanto a eficiencia alimentar dos demais grupos (p< 0,05). Em relacao a composicao corporal, constatou-se reducao dos teores de gordura corporal dos grupos AE2 (11,2%) e AE4 (11,6%), quando comparados ao teor do grupo-controle (13,9%). A suplementacao com acido linoleico conjugado nas concentracoes de 2,0% e 4,0% sobre o consumo diario de dieta promoveu reducao de gordura corporal de 18,0% nos ratos Wistar.

Adições crescentes de ácido fítico à dieta não interferiram na digestibilidade da caseína e no ganho de peso em ratos

O crescente consumo de alimentos de origem vegetal, sejam como fontes proteicas com baixo teor de gorduraou como fontes de fibras, tem acrescido a dieta humana o acido fitico. Devido a sua carga altamente negativa,o acido fitico tem sido visto como componente de acao antinutricional capaz de quelar minerais bivalentes,proteinas e amido, podendo comprometer a biodisponibilidade destes nutrientes. No presente estudoinvestigou-se a influencia da adicao de acido fitico a dieta de caseina, em concentracoes iguais ou ate oitovezes superiores aquelas encontradas no feijao-comum

Oxidation of LDL enhances the cholesteryl ester transfer protein (CETP)-mediated cholesteryl ester transfer rate to HDL, bringing on a diminished net transfer of cholesteryl ester from HDL to oxidized LDL

Cholesteryl ester transfer protein (CETP) plays a controversial role in atherogenesis by contributing to the net transfer of high density lipoprotein (HDL) cholesteryl ester (CE) to the liver via apolipoprotein-B-containing lipoproteins (apoB-LP). We evaluated in vitro the CETP-mediated bidirectional transfer of CE from HDL to the chemically modified pro-atherogenic low density lipoprotein (LDL) particles. Acetylated or oxidized (ox) LDL, either unlabeled or [3H]-CE labeled, were incubated with [14C]-CE-HDL in the presence of the lipoprotein-deficient plasma fraction (d>1.21 g/ml) as the source of CETP. The amount of radioactive CE transferred was determined after dextran sulfate/MgCl(2) precipitation of LDL. The results showed a 1.4-2.8-fold lower HDL-CE transfer to acetylated LDL while no effect was observed on the CE transfer to oxidized LDL. However, the reverse transfer rate of [3H]CE-LDL to HDL was 1.4-3.6 times greater when LDL was oxidized than when it was intact. Overall, HDL(2) was better than HDL(3) as donor of CE to native LDL, probably reflecting the relatively greater CE content of HDL(2). Oxidation of LDL enhanced the CETP-mediated cholesteryl ester transfer rate to HDL, bringing on a reduced net transfer rate of cholesteryl ester from HDL to ox LDL. This may diminish the oxLDL particles atherogenic effect.

Effect of conjugated linoleic acid supplementation on lipoprotein lipase activity in 3T3-L1 adipocyte culture

A suplementacao com acido linoleico conjugado pode reduzir a gordura corporal e aumentar a massa magra em diferentes especies. Alguns estudos tem demonstrado que o acido linoleico conjugado reduz a gordura corporal, por meio da inibicao da atividade de lipase lipoproteica em adipocitos. O objetivo deste estudo foi avaliar o efeito da suplementacao com uma mistura de isomeros do acido linoleico conjugado sobre a atividade da lipase lipoproteica em cultura de adipocitos 3T3-L1. Os adipocitos 3T3-L1 receberam acido linoleico (grupo controle) ou acido linoleico conjugado (grupo AE, suplementado com AdvantEdge® CLA, e grupo CO, suplementado com CLA One®) na concentracao de 1 mmol/L. A atividade de lipase lipoproteica livre de heparina foi analisada pela media da cultura de adipocitos. Apos 7 dias, a atividade da lipase lipoproteica livre de heparina mostrou menores valores nos grupos AE e CO, suplementados com acido linoleico conjugado. Estes resultados sugerem que um dos mecanismos pelo qual o acido linoleico conjugado seja capaz de reduzir a gordura corporal e a partir da reducao da atividade da lipase lipoproteica.

Conjugated linoleic acid supplementation: lipid content and hepatic histology in healthy Wistar rats

This work aimed to evaluate the effects of the consumption of two commercial conjugated linoleic acid (CLA) mixtures on lipid content and liver histology of healthy rats. The investigation was carried out using thirty rats divided into three groups: C (control), AE (AdvantEdge®CLA), and CO (CLA One®). The concentration of CLA was 2% of feed consumption, and the animals were supplemented daily for 42 days. The total lipid content of the liver was determined, and the histology of the organ was examined by Transmission Electronic Microscopy. The results of total liver lipid contents did not exhibit significant differences between the groups. With regard to hepatic histology, it was observed that although fat globules were visibly present in higher numbers and bigger size in the CLA groups, the organ histology was considered normal since both cytoplasm and organelles showed integrity. It was concluded that even though liver microscopic images indicated the presence of fat globules in the liver, from a statistical point of view, the supplementation for 42 days did not bring about lipid accumulation, nor did it alter hepatic histology.O objetivo do trabalho foi avaliar o efeito da suplementacao com duas misturas comerciais de acido linoleico conjugado (CLA) sobre o conteudo de lipides e a histologia hepatica de ratos saudaveis. Trinta ratos foram divididos em tres grupos: C (controle), AE (AdvantEdge®CLA) e CO (CLA One®). A concentracao de CLA foi de 2% em relacao ao consumo diario de dieta, e os animais foram suplementados diariamente durante 42 dias. O conteudo de lipides totais foi determinado e a histologia hepatica foi examinada por meio de Microscopia Eletronica de Transmissao. Nao houve diferenca significativa nos resultados de conteudo de lipides hepaticos entre os grupos. Quanto a histologia hepatica, embora tenha sido observada a presenca de globulos de gordura em maior numero e tamanho nos grupos suplementados com CLA, a histologia do orgao apresentou-se normal, visto que citoplasma e organelas estavam integros. Concluiu-se que nao houve acumulo de lipides nem alteracao da histologia hepatica apos 42 dias de suplementacao com CLA.

Soaking domestic procedure and its effect on nutritive value of common bean (Phaseolus vulgaris, L.)

O feijão-comum ( Phaseolus vulgaris ) é a principal fonte protéica dentre a família das leguminosas, consumida pela população brasileira, tomando-se em conta os alimentos isolados. A produção de grãos no ano de 1995 foi de 2 946 267 toneladas no Brasil, sendo 229 740 toneladas no Estado de São Paulo (Instituto ..., 1991). Os grãos possuem de 20 a 35% de proteína, dependendo do cultivo e do cultivar. Tal teor protéico, assim como a produção, são altos, porém o valor nutritivo da proteína não é satisfatório. As proteínas do feijão apresentam teores baixos de alguns aminoácidos essenciais limitantes, mais particularmente os sulfurados, metionina, cisteína e cistina, além do triptofano (Sgarbieri, 1996). Por outro lado apresentam baixa digestibilidade, quando comparadas às proteínas de origem animal (Yañes et al., 1995; Sgarbieri, 1996). Além disso, o feijão

Efeitos da dieta suplementada com ômega-3 no músculo sóleo de ratos submetidos à natação: análise histológica e morfométrica

Muscle injuries have been observed as the most frequent in sports. Considering the production of Reactive Oxygen Species as a risk factor for installation of injuries and antioxidant and anti-inflammatory characteristics of Omega-3, the objective of this study was to evaluate the histological and morphometric changes of the soleus muscle of rats that practiced swimming, associated with a diet supplemented with Omega-3. 31 Wistar rats divided into 4 groups were used, namely groups A and C supplemented with olive oil and B and D with 3g/day of Omega-3, for 4 weeks. Groups C and D were submitted to swimming for 5 days / week during 28 days, with addition of 5% of body weight from the second week on; while groups A and B did not perform training. After this period the animals were sacrificed, the soleus muscle removed and stained with hematoxylin and eosin for morphological evaluation. Bifactorial analysis of variance with significance level of 5% was used for analysis of values of smallest diameter of the muscle fibers. Groups A and B (sedentary) presented normal histological patterns. Group C showed increase of endomisial tissue and number of nuclei, presence of phagocytized fibers and not maintained polygonal contours, whereas group D showed few phagocytized fibers and polygonal contours preserved. Regarding the measurement of the smallest diameter of the muscle fibers, the analyses showed differences for the training factor, but not for the supplementation factor or interaction between them. The histological changes induced by exercise were attenuated in the group supplemented with Omega-3, suggesting hence a protective effect of supplementation; however, the diameter increase of the fibers for the groups exposed to exercise is related to the training effect and not to supplementation.

O EFEITO DA SUPLEMENTAÇÃO COM ÁCIDO LINOLÉICO CONJUGADO SOBRE O PERFIL LIPÍDICO SÉRICO EM RATOS

O acido linoleico conjugado (CLA), um conjunto de isomeros geometricos e de posicao do acido linoleico, vem sendo muito estudado devido aos seus efeitos beneficos em relacao a saude. O objetivo deste trabalho foi avaliar o efeito da suplementacao com acido linoleico conjugado sobre o perfil lipidico de ratos Wistar saudaveis em crescimento. Um total de 40 ratos, divididos em 4 grupos de 10 foram suplementados diariamente durante 3 semanas com AdvantEdge® CLA (EASTM) nas concentracoes 1%, 2% e 4% sobre o consumo diario de dieta, constituindo respectivamente os grupos AE1, AE2 e AE4, e com acido linoleico na concentracao de 2% sobre o consumo diario de dieta, constituindo o grupo controle (C). Os animais foram suplementados por meio de entubacao orogastrica. Para a avaliacao do perfil lipidico, o sangue dos animais foi coletado sob anestesia apos jejum de 12 horas e a determinacao dos triacilglicerois e colesterol total sericos realizada com a utilizacao de kits enzimaticos. Nao houve diferenca estatistica entre os teores de triacilglicerois (p≤0,05). Quanto aos valores de colesterol total, o grupo AE1 apresentou um teor superior ao grupo controle, ocorrendo uma reducao dos valores a medida que aumentava a quantidade suplementada de CLA.