N-acetilcisteína e frutose-1, 6-bisfosfato: efeito imunomodulador em cultura de células mononucleares / N-acetilcisteína e frutose-1,6-bisfosfato: efeito imunomodulador em cultura de células mononucleares

INTRODUCTION: Sepsis is a complex syndrome caused by an uncontrolled systemic inflammatory response. Inflammatory cytokines play a pivotal role in septic shock pathogenesis. Therapeutic strategies have been tested in order to modulate the excessive generation or function of sepsis mediators. OBJECTIVE: The objective of the present study was to investigate the therapeutic effect of N-acetylcysteine (NAC) and its association with fructose-1,6-bisphosphate (FBP) on T-lymphocytes proliferation, interleukin-1β (IL-1β) and monocyte chemotactic protein-1 (MCP-1) levels. MATERIAL AND METHODS: Peripheral blood mononuclear cell samples were isolated from healthy individuals. T-lymphocytes were stimulated with phytohemagglutinin for 96 hours and submitted to different concentrations of NAC or NAC associated with FBP. RESULTS: NAC (10 and 15 mM) and NAC (15 mM) associated with FBP reduced T-lymphocytes proliferation. IL-1β levels rose in the presence of both NAC (15 mM) and NAC with FBP (1.25 mM). MCP-1 levels were reduced only by NAC (15 mM) associated with FBP (1.25 mM). CONCLUSION: The results suggest that both NAC itself and NAC associated with FBP inhibit cellular proliferation, acting as potent immunomodulatory agents, which corroborates its use in the treatment of inflammatory diseases.

INTRODUÇÃO: A sepse é uma síndrome complexa causada pela resposta inflamatória sistêmica descontrolada. As citocinas inflamatórias representam papel central na patogênese do choque séptico. Têm sido testadas estratégias terapêuticas a fim de modular a geração ou a função excessiva de mediadores na sepse. OBJETIVO: O objetivo deste estudo foi investigar o efeito terapêutico da N-acetilcisteína (NAC) e sua associação com a frutose-1,6-bisfosfato (FBP) sobre a proliferação de linfócitos T e a geração de interleucina-1β (IL-1β) e proteína quimiotática de monócitos 1 (MCP-1) em cultura celular. MATERIAL E MÉTODOS: Foram isoladas células mononucleares de sangue periférico de indivíduos saudáveis. Os linfócitos T foram estimulados por 96 horas com fitohemaglutinina e submetidos a diferentes concentrações de NAC ou NAC associada à FBP (1,25 mM). RESULTADOS: O tratamento com NAC (10 e 15 mM) ou NAC (15 mM) associado à FBP reduziu a proliferação celular. Os níveis de IL-1β aumentaram com a presença de NAC (15 mM) e NAC + FBP. A concentração de MCP-1 mostrou-se reduzida apenas no grupo tratado com NAC associada à FBP. CONCLUSÃO: Os resultados sugerem que tanto a NAC quanto a NAC associada à FBP são capazes de inibir a proliferação celular, atuando como potentes agentes imunomoduladores, sugerindo seu uso em doenças inflamatórias.

Recent advance in the discovery of allosteric inhibitors binding to the AMP site of fructose-1,6-bisphosphatase / 药学学报

Fructose-1, 6-bisphosphatase (FBPase), a rate-limiting enzyme involved in the pathway of gluconeogenesis, can catalyze the hydrolysis of fructose-1, 6-bisphosphate to fructose-6-phosphate. Upon inhibiting the activity of FBPase, the production of endogenous glucose can be decreased and the level of blood glucose lowered. Therefore, inhibitors of FBPase are expected to be novel potential therapeutics for the treatment of type II diabetes. Recent research efforts were reviewed in the field of developing allosteric inhibitors interacting with the AMP binding site of FBPase.

Isolamento de ilhotas pancreáticas e a alternativa de uso da frutose-1, 6-bisfosfato: [revisão] / Pancreatic islet isolation and the alternative use of fructose-1, 6-bisphosphate: [review]

Objetivos: revisar dados da literatura sobre isolamento de ilhotas pancreáticas para transplante e sobre as ações da frutose-1,6-bisfosfato. Fonte de dados: revisão de artigos publicados, a partir da pesquisa em bancos de dados nacionais e internacionais (SciELO, Lilacs, PubMed). Síntese dos dados: o transplante de ilhotas surge como uma alternativa para o tratamento do diabetes mellitus tipo 1. Entretanto, durante o processo de isolamento, há grande perda celular, principalmente na periferia da ilhota pancreática. As espécies reativas de oxigênio contribuem significativamente nesse processo, afetando a viabilidade das células para transplante. Vários esforços estão sendo feitos na tentativa de minimizar os danos causados pela liberação e produção destes compostos químicos. Conclusões: frente às importantes ações da frutose-1,6-bisfosfato descritas na literatura, seu emprego durante o processo de isolamento das ilhotas pancreáticas parece ser uma alternativa bastante atraente. O efeito da frutose-1,6-bisfosfato na redução da formação e liberação de radicais livres, assim como a sua ação citoprotetora, poderiam viabilizar um maior número de células, otimizando o processo de isolamento, além de auxiliar na enxertia, por diminuir a liberação de citocinas pró-inflamatórias.

Aims: To review the literature data about pancreatic islet isolation and fructose-1,6-bisphosfate. Source of data: Review of specific articles on the issue published in national and internacional databases (SciELO,Lilacs, PubMed). Summary of findings: Islets transplantation is an alternative for the treatment of type 1 diabetes mellitus. However, during the process of isolation, cell loss, mainly on the periphery of the pancreatic islet, ensues. Reactive oxygen species seem to contribute significantly in this process, affecting the viability of these cells. Various efforts are being made in an attempt to minimize the damage caused by the release and production of reactive oxygen species. Conclusions: Considering the important actions of fructose-1,6-bisphosphate which are described in the literature, its use in pancreatic islet isolation may represent an attractive alternative. The effect of fructose-1,6-bisphosphate in reducing the production and release of free radicals, as well as its role in cellular protection, could enable a greater number of viable cells, optimizing the isolation process, and also protecting the graft process, by reducing the release of proinflammatory cytokines.

Modulatory effect of Gynandropsis gynandra L. on glucose metabolizing enzymes in aflatoxin B1-induced hepatocellular carcinoma in rats.

The modulation of glucose-metabolizing enzymes activities play a vital role in the depletion of energy metabolism and leads to inhibition of cancer growth. In the present study, the effect of Gynandropsis gynandra L. extract on aflatoxin B1 (AFB1)-induced hepatocellular carcinoma (HCC) was studied on glucose-metabolizing enzymes in rats. A significant increase (p < 0.001) in the activities of the key glycolytic enzymes viz., hexokinase and phosphoglucoisomerase, with a significant decrease (p < 0.001) in the gluconeogenic enzymes glucose-6-phosphatase and fructose-1,6-bisphosphatase were observed in HCC-bearing rats, when compared with the control. Administration of G. gynandra extract caused a significant decrease in the activities of glycolytic enzymes and an increase in the gluconeogenic enzymes activities to near normal values. Thus, findings suggest the G. gynandra extract has a definite modulating role on the key enzymes of glucose metabolism in HCC. The modulatory effect may be due to the phytoactive constituents present in the extract of G. gynandra.

Studies on glucose-metabolizing enzymes in cytosolic and bacteroidal fractions of mungbean (Vigna radiata L.) and lentil (Lens culinaris L.) nodules.

Nitrogen is exported in the form of ureides or amides from the nodules in pulse crops. In order to understand the carbon metabolism in ureide and amide exporting nodules, activities of enzymes involved in glucose metabolism were compared in cytosolic and bacteroidal fractions of mungbean (ureide exporter) and lentil (amide exporter) nodules during development. Activities of hexokinase, fructokinase, phosphoglucomutase, fructose-1,6-bisphosphatase, phosphohexose isomerase and UDP-glucose pyrophosphorylase were detected in cytosolic fraction of nodules of both the crops during development. Out of these enzymes, specific activity of phosphohexose isomerase was the highest in nodules of both the crops, in comparison with other enzymes. In comparison with mungbean, activities of various enzymes were less in cytosolic fraction of lentil. Activities of hexokinase, fructokinase, phosphoglucomutase were present only in cytosolic fraction of mungbean (Vigna radiata L.), however, low activity of these enzymes was also observed in lentil (Lens culinaris L.) bacteroids. Activities of phosphohexose isomerase and fructose-1,6-bisphosphatase were higher in bacteroids of lentil, as compared to mungbean during early nodule development, but this pattern was reversed with progress of crop development. Higher activities of phosphoglucomutase and fructose-1,6-phosphatase in mungbean cytosolic fraction could lead to increased flow of carbon towards pentose phosphate pathway.

Ação da frutose-1, 6-biofosfato sobre a toxicidade aguda do ácido nicotínico / Fructose-1, 6-bisphosphate action in nicotinic acid acute toxicity-induced

O ácido nicotínico (niacina) se mostra como um agente que reduz o nível de colesterol total, lipídios de baixa densidade (LDL) e triglicerídeos, sendo efetivo na terapia para regulação lipoprotéica e redução de risco cardiovascular. A toxicidade hepática é um efeito potencialmente sério da terapia com niacina. Já são bem descritos os efeitos da frutose-1,6-biofosafato na injúria de diferentes órgãos, além de apresentar-se protetora em lesões tóxicas. A toxicidade aguda sobre os perfis lípidico e hepático do ácido nicotínico, bem como a ação da frutose-1,6-biofosfato, como proteção na ação letal do ácido, são os alvos deste estudo. A dose de 800mg/kg intraperitoneal de ácido nicotínico é capaz de levar a óbito 25% dos ratos analisados. Mostra-se que o ácido exerce ação sobre os lípídios, diminuindo os valores de colesterol, mas não os de triglicérides. A lesão hepática decorrente do uso crônico do ácido nicotínico não é reproduzido na análise aguda, sendo que a causa da mortandade dos animais não é conhecida. Elucida-se também que a frutose-1,6-bisfosfato 500mg/kg, via subcutânea, não é competente no alento dos ,ales causados pelo ácido, ao contrário, potencializa a ação da niacina ao provocar aumento dos níveis de lactato desidrogenase.

Efeito da frutose-1, 6bisfosfato sobre os níveis séricos e urinários de lactato em ratos com sepse experimental / Effect of fructose-1, 6-bisphosphate on serum and urine levels of lactate in rats with experimental sepsis

As alterções celulares e sistêmicas durante a sepse ocasionam distúrbios na circulação, queda na perfuração tecidual e consequentemente déficit de energia celular. A frutose-1-6-bisfosfato (FBP) tem demonstrado efeitos protetores em diversas situações patológicas, inclusive sepse. O objetivo deste travalho foi verificar a concentração de FBP em animais com sepse experimental. Estudo controlado em ratos Wistar divididos em 4 grupos: grupo controle com FBP(500 mg/kg). A concentração sérica de lactato aumentou signitivamente no grupo séptico. Analisando a depuração de creatinina endógena(DCE) verificou-se, que somente o grupo séptico apresentou uma diminuição significativa. Já o lactato urinário não demonstrou alterações entre os grupos de controle, séptico e séptico tratado, aumentando, porém significativamente no grupo co FBP. Este estudo demonstrou que o lactato urinário é bom marcador de perfusão tecidual na spse. Também pôde-se verificar que a ação protetora da FBP não é por melhora da perfusão tecidual, mas provavelmente por outros efeitos já descritos, tais como, ação antiflamatória, manutenção dos níveis de energia da célula, estabilização da membrana celular.

Biochemical studies on hypoglycemic effect of Aavirai kudineer: a herbal formulation in alloxan diabetic rats.

Aavirai Kudineer (AK) is an herbal decoction of seven botanical drugs, cited in the Gunapadam; a Tamil Siddha medical text. The anti-diabetic efficacy of this formulation was evaluated using alloxan-induced diabetic and normal rats. Glucose tolerance was observed within 1 hr in AK-treated rats (10 ml/kg body ) as compared to control. A significant decrease in the severe hyperglycemia characteristic of alloxan diabetes was noted after 15 days of AK treatment. Further AK treatment reversed the elevated urea, creatinine, cholesterol and decreased protein values to near normal levels. Assay of glycogen content and chief carbohydrate-metabolizing enzymes, viz. hexokinase, glucose-6-phosphatase and fructose 1,6 diphosphatase in the liver of diabetic and AK-treated diabetic rats clearly ascertains the hypoglycemic efficacy of this formulation. The mode of action of this herbal formulation remains to be elucidated.

Influence of exercise on the activity and the distribution between free and bound forms of glycolytic and associated enzymes in tissues of horse mackerel

The effects of short-term burst (5 min at 1.8 m/s) swimming and long-term cruiser (60 min at 1.2 m/s) swimming on maximal enzyme activities and enzyme distribution between free and bound states were assessed for nine glycolytic and associated enzymes in tissues of horse mackerel, Trachurus mediterraneus ponticus. The effects of exercise were greatest in white muscle. The activities of phosphofructokinase (PFK), pyruvate kinase (PK), fructose-1,6-bisphosphatase (FBPase), and phosphoglucomutase (PGM) all decreased to 47, 37, 37 and 67 percent, respectively, during 60-min exercise and all enzymes except phosphoglucoisomerase (PGI) and PGM showed a change in the extent of binding to subcellular particulate fractions during exercise. In red muscle, exercise affected the activities of PGI, FBPase, PFK, and lactate dehydrogenase (LDH) and altered percent binding of only PK and LDH. In liver, exercise increased the PK activity 2.3-fold and reduced PGI 1.7-fold only after 5 min of exercise but altered the percent binding of seven enzymes. Fewer effects were seen in brain, with changes in the activities of aldolase and PGM and in percent binding of hexokinase, PFK and PK. Changes in enzyme activities and in binding interactions with subcellular particulate matter appear to support the altered demands of tissue energy metabolism during exercise

Modulation of some gluconeogenic enzyme activities in diabetic rat liver and kidney: effect of antidiabetic compounds.

The effects of insulin, sodium orthovanadate and a hypoglycemic plant material, Trigonella foenum graecum (fenugreek) seed powder were studied on the activities of glucose-6-phosphatase and fructose-1,6-bisphosphatase in diabetic liver and kidney. The significantly increased activities of the two enzymes during diabetes in liver and kidney were found to be lowered to almost control values by the use of the antidiabetic compounds. Diabetic liver exhibited a much greater increase in the activities of the two enzymes than diabetic kidney. The highest percentage of reversal to normal values was seen using the combination of vanadate and Trigonella seed powder. The lowered rate of growth of the animals as well as the increased blood sugar were reversed almost to the control levels by the Trigonella seed powder and vanadate treatment. The inclusion of the Trigonella seed powder overcame the toxicity of vanadium encountered when it was given alone as insulin mimetic agent. Much lower levels of vanadate were needed when it was given in combination with Trigonella seed powder. Their combined effects were better at restoring the above parameters than those induced by insulin administration.

Efeito da frutose-1, 6-bifosfato na preservação de rins de ratos / Effects of Fructose-1, 6-diphosphate on kidney preservation of rats

A perfusão para preservaçao de rins para transplantes tem por finalidade a manutenção da viabilidade do órgão, lavá-lo internamente para remover o sangue e de manter a atividade celular até a revascularização. A frutose-1, 6- bisfosfato apresenta efeito de proteção celular em situações diversas, tais como isquemia e toxicidade de drogas...

Efeito da frutose-1, 6-bifosfato na preservaçäo de rins de ratos / Effects of Fructose-1, 6-diphosphate on kidney preservation of rats

A perfusão para preservaçao de rins para transplantes tem por finalidade a manutenção da viabilidade do órgão, lavá-lo internamente para remover o sangue e de manter a atividade celular até a revascularização. A frutose-1, 6- bisfosfato apresenta efeito de proteção celular em situações diversas, tais como isquemia e toxicidade de drogas...

Determinación de la actividad de la fructosa 1.6 difosfatasa en leucocitos / Determination of the activity of the fructose 1.6 diphosphatase in leukocyte

En el presente estudio se estandariza la técnica para la determinación de la actividad de la enzima fructosa 1.6 difosfatasa en leucocitos aislados de sangre periférica, dicha enzima es de gran importancia en el proceso de la gluconeogénesis, su deficiencia es causada por un desorden metabólico de origen primario, autosómico, recesivo, que se manifiesta principalmente con hipoglicemia y acidosis metabólica. Proponemos un método diferente al tradicional de detección que se basa en el análisis enzimático realizado en biopsias de hígado. Los valores de la actividad catalítica específica en adultos sanos obtenidos por la técnica utilizaa en ese estudio, comparados con los de otros autores, demuestran que mediante la metodología estandarizada en este trabajo se detecta una mayor actividad enzimática.

Photosynthetic carbon reduction cycle metabolites and enzymes of sucrose and starch biosynthesis in developing Brassica pods.

Rate of net CO2 exchange and activities of the key enzymes of fru-2,6-P2, sucrose and starch synthesis and levels of certain intermediates of Calvin cycle were determined in Brassica pods at different stages of their development. The rate of net CO2 exchange, activities of FBPase, UDPG-pyrophosphorylase and SPS, and the contents of 3-PGA, DHAP, RuBP and UDPG increased up to day 21 after anthesis followed by a continuous decrease thereafter. However the content of fru-6-P started decreasing only after 28 days of anthesis. Changes in the levels of fru-2,6-P2 were closely associated with the changes in F6P 2-kinase activity rather than with F2,6-P2ase activity. Similarly, activities of ADPG-pyrophosphorylase and ADPG-starch synthetase closely followed the pattern of starch accumulation in pod tissues. These observations suggest that during the early phase of pod development (up to 21 days after anthesis), which is also the active phase for pod photosynthesis, carbon is mainly utilised for sucrose synthesis and that during the later phase of pod development (from day 21 to 42 after anthesis), there is shift in metabolic path of carbon from sucrose to starch.

Comparative study of phosphofructokinase from rat small intestine and liver. Control by fructose-2,6-bisphosphate and other effectors

As compared to the liver, intestinal mucosa shows a high rate of aerobic glycolysis. This difference has been attributed to the higher activity of the intestinal phosphofructokinase (PFK) isoenzyme. The regulatory properties of rat small intestine and liver PFK were investigated. At pH 8, where PFK activity can be evaluated free of allosteric influences, the specific activity of the liver isoenzyme was 25%higher that of the intestinal one, At pH 7, the mucosal PFK was activated to 80%of its maximal activity at pH 8, while the liver enzyme showed only a 40%activation. The apparent Kms for Fructose-6-P were 0.47 and 1.03 mM for the mucosal and hepatic isoenzymes, respectively. At 2 mM Fructose-6-P, the optimal ATP concentration for both isoenzymes was 1 mM Hogher ATP concentrations strongly anhibited both enzymes, but below 3 mM, PFK activity was larger in the mucosal homogenate. In addition, the intestinal PFK was more sensitive to activation by Fructose-2,6-bisphosphate and 6-phosphogluconate, particulary at low Fructose-6-p concentrations, and by AMP below 0.3 mM. These studies suggest that, under physiological conditions, the intestinal isoenzyme is more active than its liver counterpart. This may acccunt for the high rate of aerobic glycolysis observed in the intestinal mucosa