Methionine-supplemented diet affects the expression of cardiovascular disease-related genes and increases inflammatory cytokines in mice heart and liver.

Some important environmental factors that influence the development of cardiovascular diseases (CVD) include tobacco, excess alcohol, and unhealthy diet. Methionine obtained from the diet participates in the synthesis of DNA, proteins, lipids and affects homocysteine levels, which is associated with the elevated risk for CVD development. Therefore, the aim of this study was to investigate the manner in which dietary methionine might affect cellular mechanisms underlying CVD occurrence. Swiss albino mice were fed either control (0.3% DL-methionine), methionine-supplemented (2% DL-methionine), or a methionine-deprived diet (0% DL-methionine) over a 10-week period. The parameters measured included plasma homocysteine concentrations, oxidative stress by reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio, levels of inflammatory cytokines IL-1ß, TNF-α, and IL-6, as well as expression of genes associated with CVD. The levels of apolipoprotein A5 (APOA5), a regulator of plasma triglycerides, were measured. The methionine-supplemented diet increased oxidative stress by lowering the GSH/GSSG ratio in heart tissues and decreased expression of the genes Apob, Ctgf, Serpinb2, Spp1, Il1b, and Sell, but elevated expression of Thbs4, Tgfb2, Ccr1, and Vegfa. Methionine-deprived diet reduced expression of Col3a1, Cdh5, Fabp3, Bax, and Hbegf and increased expression of Sell, Ccl5, Itga2, Birc3, Msr1, Bcl2a1a, Il1r2, and Selp. Methionine-deprived diet exerted pro-inflammatory consequences as evidenced by elevated levels of cytokines IL-1ß, TNF-α, and IL-6 noted in liver. Methionine-supplemented diet increased hepatic IL-6 and cardiac TNF-α. Both methionine supplementation and deprivation lowered hepatic levels of APOA5. In conclusion, data demonstrated that a methionine-supplemented diet modulated important biological processes associated with high risk of CVD development.

L-arginine, a nitric oxide precursor, reduces dapsone-induced methemoglobinemia in rats

Dapsone use is frequently associated to hematological side effects such as methemoglobinemia and hemolytic anemia, which are related to N-hydroxylation mediated by the P450 enzyme system. The aim of the present study was to evaluate the influence of L-arginine supplementation, a precursor for the synthesis of nitric oxide, as single or multiple dose regimens on dapsone-induced methemoglobinemia. Male Wistar rats were treated with L-arginine at 5, 15, 30, 60 and 180 mg/kg doses (p.o., gavage) in single or multiple dose regimens 2 hours prior to dapsone administration (40 mg/kg, i.p.). The effect of the nitric oxide synthase inhibitor L-NAME was investigated by treatment with multiple doses of 30 mg/kg (p.o., gavage) 2 hours before dapsone administration. Blood samples were collected 2 hours after dapsone administration. Erythrocytic methemoglobin levels were assayed by spectrophotometry. The results showed that multiple dose supplementations with 5 and 15 mg/kg L-arginine reduced dapsone-induced methemoglobin levels. This effect is mediated by nitric oxide formation, since the reduction in methemoglobin levels by L-arginine is blocked by simultaneous administration with L-NAME, a nitric oxide synthase inhibitor.

O uso da dapsona é frequentemente associado a efeitos adversos hematológicos, como a metemoglobinemia e anemia hemolítica, ambos relacionados com a N-hidroxilação mediada pelo sistema P450. O objetivo do estudo foi avaliar a influência da suplementação de L-arginina, um precursor da síntese de óxido nítrico, administrado em regime de dose única ou múltipla na metemoglobinemia induzida pela dapsona. Ratos machos Wistar foram tratados com L-arginina (po, gavagem) em dose única ou múltipla de 5, 15, 30, 60 e 180 mg/kg 2 horas antes da administração de dapsona (40 mg/kg, ip). O efeito do L-NAME, um inibidor de óxido nítrico sintase (NOS), foi avaliado através do tratamento com doses múltiplas de 30 mg/kg. Amostras de sangue foram coletadas duas horas após a administração de dapsona. A concentração de metemoglobina eritrocitária foi analisada por espectrofotometria. Os resultados mostraram que a suplementação em dose múltipla de 5 e 15 mg/kg de L-arginina reduziu os níveis de metemoglobina induzida pela dapsona. Este efeito é mediado pela formação de óxido nítrico, uma vez que a redução nos níveis de metemoglobina pela L-arginina é bloqueada pela administração simultânea de L-NAME, um inibidor da óxido nítrico sintase.

The effects of dietary supplementation of methionine on genomic stability and p53 gene promoter methylation in rats.

Methionine is a component of one-carbon metabolism and a precursor of S-adenosylmethionine (SAM), the methyl donor for DNA methylation. When methionine intake is high, an increase of S-adenosylmethionine (SAM) is expected. DNA methyltransferases convert SAM to S-adenosylhomocysteine (SAH). A high intracellular SAH concentration could inhibit the activity of DNA methyltransferases. Therefore, high methionine ingestion could induce DNA damage and change the methylation pattern of tumor suppressor genes. This study investigated the genotoxicity of a methionine-supplemented diet. It also investigated the diet's effects on glutathione levels, SAM and SAH concentrations and the gene methylation pattern of p53. Wistar rats received either a methionine-supplemented diet (2% methionine) or a control diet (0.3% methionine) for six weeks. The methionine-supplemented diet was neither genotoxic nor antigenotoxic to kidney cells, as assessed by the comet assay. However, the methionine-supplemented diet restored the renal glutathione depletion induced by doxorubicin. This fact may be explained by the transsulfuration pathway, which converts methionine to glutathione in the kidney. Methionine supplementation increased the renal concentration of SAH without changing the SAM/SAH ratio. This unchanged profile was also observed for DNA methylation at the promoter region of the p53 gene. Further studies are necessary to elucidate this diet's effects on genomic stability and DNA methylation.

Evaluation of the genotoxic and antigenotoxic effects after acute and subacute treatments with açai pulp (Euterpe oleracea Mart.) on mice using the erythrocytes micronucleus test and the comet assay.

Açai, the fruit of a palm native to the Amazonian basin, is widely distributed in northern South America, where it has considerable economic importance. Whereas individual polyphenolics compounds in açai have been extensively evaluated, studies of the intact fruit and its biological properties are lacking. Therefore, the present study was undertaken to investigate the in vivo genotoxicity of açai and its possible antigenotoxicity on doxorubicin (DXR)-induced DNA damage. The açai pulp doses selected were 3.33, 10.0 and 16.67g/kg b.w. administered by gavage alone or prior to DXR (16mg/kg b.w.) administered by intraperitoneal injection. Swiss albino mice were distributed in eight groups for acute treatment with açai pulp (24h) and eight groups for subacute treatment (daily for 14 consecutive days) before euthanasia. The negative control groups were treated in a similar way. The results of chemical analysis suggested the presence of carotenoids, anthocyanins, phenolic, and flavonoids in açai pulp. The endpoints analyzed were micronucleus induction in bone marrow and peripheral blood cells polychromatic erythrocytes, and DNA damage in peripheral blood, liver and kidney cells assessed using the alkaline (pH >13) comet assay. There were no statistically significant differences (p>0.05) between the negative control and the groups treated with the three doses of açai pulp alone in all endpoints analyzed, demonstrating the absence of genotoxic effects. The protective effects of açai pulp were observed in both acute and subacute treatments, when administered prior to DXR. In general, subacute treatment provided greater efficiency in protecting against DXR-induced DNA damage in liver and kidney cells. These protective effects can be explained as the result of the phytochemicals present in açai pulp. These results will be applied to the developmental of food with functional characteristics, as well as to explore the characteristics of açai as a health promoter.

In vivo cytogenetic effects of multiple doses of dietary vegetable oils

Polyphenols are potent antioxidants that are particularly abundant in the Mediterranean diet, with olive oil being the main fat source. A number of investigations have reported that phenolic compounds found in dietary oils are antioxidants and could provide protective effects by inhibiting DNA oxidative damage. However, few studies have been published on the biological activity of vegetable oils, including their possible mutagenic/antimutagenic effects. The objective of the current study was to investigate the cytogenetic effects of multiple doses of four vegetable oils in rat bone marrow cells and to examine the possible antimutagenic effects of these oils in chromosomal damage induced by the antitumor drug cisplatin. These oils are consumed by humans and commonly used as drug vehicles. The rats received treatment with multiple doses of canola oil, olive oil, virgin olive oil, and corn oil (5 mL kg-1) alone or combined with the antitumor drug cisplatin (5 mg kg-1). Treatments with vegetable oils alone did not increase the percentage of cells with chromosomal aberrations (p > 0.05). Olive, virgin olive and canola oils showed protective effects against cisplatin-induced chromosomal damage (p < 0.05). A rational mechanism for the protective effects of vegetable oils is that their phenolic compounds have antioxidant and antimutagenic properties in vivo.

Iron derivatives from casein hydrolysates as a potential source in the treatment of iron deficiency.

The properties of an Fe(3+)-peptide complex containing 5.6% Fe, obtained by the reaction of ferric chloride with an enzymatic hydrolysate of casein, are described. The major site of iron binding corresponds primarily to the carboxylate groups and to a lesser extent to the peptide bonds. The Fe(3+)-peptide complex is insoluble at acid pH and completely soluble at neutral to alkaline pH. When soluble, the Fe(3+) is tightly bound to the complex peptide mixture but can be displaced and complexed by a low molecular weight ligand such as cysteine. Its efficacy in relation to iron sulfate was compared in rats. Both iron sources were administrated in Milli-Q water by gastric gavage to male Wistar rats (180-200 g) after an 18 h fast with water ad libitum. Fe(3+) from the Fe(3+)-peptide complex was transferred to the blood in a dose-dependent manner (1-8 mg of Fe/kg), and the serum iron levels were significantly higher (p < 0.001) than in a similar group of rats treated with iron sulfate. In the comparative kinetics experiments, the rats received 4 mg of Fe/kg. Both iron sources presented maximum absorption, as indicated by the elevation of serum iron levels, 30 min after administration, and the AUC(0)(-->2h) of the Fe(3+)-peptide complex was significantly higher (p < 0.05) than that observed with iron sulfate. The simultaneous administration of free peptides (0-192 mg) with the Fe(3+)-peptide complex or iron sulfate did not modify the extent of absorption of iron from both sources, suggesting that the absorption is due to the complex formed and probably not to exchange reactions in the gastrointestinal tract. In the hemoglobin repletion experiments carried out on newly weaned rats with anemia induced by a low-iron diet, supplementation of the diet with the the Fe(3+)-peptide complex was as efficient as supplementation with iron sulfate in the conversion from diet to hemoglobin iron. These results, taken together, suggest that the Fe(3+)-peptide complex is a potential compound for use as an iron source in biological situations.

Consideracoes sobre a biodisponibilidade do ferro dos alimentos / Considerations regarding eron biovailability

Neste artigo se apresenta uma revisao documentada com mais de 60 referencias sobre o tema da disponibilidade do ferro. O trabalho oferece uma secao dedicada a terminologia empregada, enfatizando a conveniencia do termo "biodisponibilidade ou disponibilidade biológica de nutrientes" que tem certa discrepancia. Depois estuda os factores extrínsecos ou fisiológicos e os fatores intrínsecos ou dietéticos que afectan a disponibilidade do ferro. A continuacao se apresenta uma discussao sobre a biodisponibilidade do ferro dos alimentos de origem animal e vegetal, dos alimentos fortificados com sais de ferro e dos alimentos com ferro provenientes de contaminacao. O artigo refere como pesquisadores compararam métodos "in vitro" e "in vivo" para determinar a biodisponibilidade do ferro, concluindo que ambos os métodos devem ser associados. Para finalizar explica que apesar das mudancas ocurridas em diversos ambitos, novas questoes surgen sobre a importancia do ferro dos alimentos na solucao do problema da deficiencia desde mineral

Utilizaçäo da água potável como veículo de nutrientes: estudos experimentais com ferro / Use of drinking water as a vehicle of nutrients: experimental studies with iron

Esta investigaçäo é parte de um projeto mayor com o objetivo de estudar a possibilidade de se usar água potável como carreador de nutrientes, tais como o ferro, para uso de comunidades. Para verificar tal possibilidade vários sais de ferro em diferentes concentraçöes foram adicionados água e analisados quanto a seus efeitos em relaçäo à cor e à turbidez. Os resultados destes estudos mostraram que o citrato férrico amoniacal foi o melhor sal no que diz respeito à manutençäo das características físicas de água potável clorada. Também foi estudada a biodisponibilidade de diversos sais de ferro adicionados a água para prevenir a anemia em ratos. Os ensaios biológicos mostraron que as formas mais adequadas de sais de ferro em água para prevenir foram: citrato férrico amoniacal, sulfato ferroso e gluconato de ferro