Consumo de cafeína durante a gestação e transtorno de déficit de atenção e hiperatividade (TDAH): uma revisão sistemática da literatura / Caffeine consumption during pregnancy and attention deficit hyperactivity disorder (ADHD): a systematic literature review / Consumo de cafeína durante el embarazo y trastorno por déficit de atención e hiperactividad (TDAH): una revisión sistemática de la literatura

O objetivo do presente estudo foi avaliar, mediante revisão sistemática da literatura, as evidências acerca da associação entre consumo materno de cafeína durante a gestação e transtorno de déficit de atenção e hiperatividade (TDAH) na infância. A busca na literatura ocorreu de forma sistemática, em múltiplas etapas, nas bases PubMed, LILACS, BIREME e PsycINFO, com limites para artigos publicados em português, inglês e espanhol, realizados em humanos. Foram encontradas 373 referências. Dessas, somente cinco foram mantidas, por atenderem ao objetivo deste estudo. Os cinco trabalhos foram realizados em países desenvolvidos; a maioria utilizou delineamento longitudinal e foi publicada nos últimos cinco anos. Apenas um estudo encontrou associação positiva. Estudos sobre o consumo de cafeína na gestação e TDAH são escassos, com resultados controversos e se deparam com várias dificuldades metodológicas, como falta de padronização na definição do desfecho.

This aim of this study was to conduct a systematic literature review on the association between maternal caffeine intake during pregnancy and attention deficit hyperactivity disorder (ADHD) in childhood. The systematic multiple-stage literature search in PubMed, LILACS, BIREME, and PsycINFO was limited to research in human subjects and published in Portuguese, English, and Spanish. A total of 373 references were retrieved. Of these, only five met the study's objectives and were kept in the review. Most of the studies employed a longitudinal design, were conducted in developed countries, and were published in the last five years. Only one study found a positive association. Studies on caffeine consumption during pregnancy and ADHD are scarce, with conflicting results and several methodological difficulties such as lack of standardized outcome measures.

El objetivo de este estudio fue evaluar, a través de una revisión sistemática de la literatura, evidencias sobre la asociación entre el consumo de cafeína durante el embarazo y el trastorno por déficit de atención e hiperactividad (TDAH) en la infancia. Se realizó una búsqueda sistemática en la literatura, por etapas múltiples, en PubMed, LILACS BIREME y PsycINFO, limitándose a artículos publicados en portugués, inglés y español, realizados en estudios sobre humanos. Fueron localizadas 373 referencias. De ellas, apenas se mantuvieron cinco, por cumplir el objetivo de este estudio. Los estudios se realizaron en países desarrollados; el diseño longitudinal fue el más utilizado y se trata de publicaciones de los últimos cinco años. Sólo un estudio encontró asociación positiva. Los estudios sobre el consumo de cafeína durante el embarazo y el TDAH son escasos, con resultados controvertidos, y enfrentan varias dificultades metodológicas, como la no estandarización de la evaluación del resultado.

Inflammatory response of endothelial cells to hepatitis C virus recombinant envelope glycoprotein 2 protein exposure

The hepatitis C virus (HCV) encodes approximately 10 different structural and non-structural proteins, including the envelope glycoprotein 2 (E2). HCV proteins, especially the envelope proteins, bind to cell receptors and can damage tissues. Endothelial inflammation is the most important determinant of fibrosis progression and, consequently, cirrhosis. The aim of this study was to evaluate and compare the inflammatory response of endothelial cells to two recombinant forms of the HCV E2 protein produced in different expression systems (Escherichia coli and Pichia pastoris). We observed the induction of cell death and the production of nitric oxide, hydrogen peroxide, interleukin-8 and vascular endothelial growth factor A in human umbilical vein endothelial cells (HUVECs) stimulated by the two recombinant E2 proteins. The E2-induced apoptosis of HUVECs was confirmed using the molecular marker PARP. The apoptosis rescue observed when the antioxidant N-acetylcysteine was used suggests that reactive oxygen species are involved in E2-induced apoptosis. We propose that these proteins are involved in the chronic inflammation caused by HCV.

Kinetoplastid membrane protein-11 exacerbates infection with Leishmania amazonensis in murine macrophages

In Leishmania amazonensis, kinetoplastid membrane protein-11 (KMP-11) expression increases during metacyclogenesis and is higher in amastigotes than in promastigotes, suggesting a role for this protein in the infection of the mammalian host. We show that the addition of KMP-11 exacerbates L. amazonensis infection in peritoneal macrophages from BALB/c mice by increasing interleukin (IL)-10 secretion and arginase activity while reducing nitric oxide (NO) production. The doses of KMP-11, the IL-10 levels and the intracellular amastigote loads were strongly, positively and significantly correlated. The increase in parasite load induced by KMP-11 was inhibited by anti-KMP-11 or anti-IL-10 neutralising antibodies, but not by isotype controls. The neutralising antibodies, but not the isotype controls, were also able to significantly decrease the parasite load in macrophages cultured without the addition of KMP-11, demonstrating that KMP-11-induced exacerbation of the infection is not dependent on the addition of exogenous KMP-11 and that the protein naturally expressed by the parasite is able to promote it. In this study, the exacerbating effect of KMP-11 on macrophage infection with Leishmania is for the first time demonstrated, implicating it as a virulence factor in L. amazonensis. The stimulation of IL-10 production and arginase activity and the inhibition of NO synthesis are likely involved in this effect.

A via L-arginina-óxido nítrico, estresse oxidativo e ciclo da uéia na obesidade / L-arginine-nitric oxide pathway, oxidative stress and urea cycle in obesity

A obesidade é um distúrbio metabólico de etiologia multifatorial e elevada prevalência no Brasil, que pode ser definida por um índice de massa corporal (peso em quilogramas dividido pela altura em metros ao quadrado) maior ou igual a 30 kg/m2, e que está associada de forma independente a um elevado risco de morbidade e mortalidade cardiovascular devido aos eventos aterotrombóticos. O óxido nítrico (NO), uma pequena molécula gasosa, é produzido através da conversão do aminoácido catiônico L-arginina em L-citrulina e NO em uma reação catalisada por uma família de enzimas denominadas NO-sintases (NOS), e funciona como um protetor cardiovascular modulando por exemplo o relaxamento do músculo liso vascular e a função plaquetária. O objetivo desta tese foi avaliar a via L-arginina-NO, bem como investigar a função plaquetária, o estresse oxidativo, e a atividade da arginase em pacientes com obesidade. O transporte de L-arginina, a produção de guanosina monofosfato cíclica (GMPc), a atividade e a expressão das isoformas da NOS (iNOS e eNOS), a atividade da arginase, o estresse oxidativo (produção de espécies reativas de oxigênio – EROs; atividade da superóxido dismutase – SOD; e atividade da catalase), bem como a função plaquetária foram medidos nas plaquetas dos pacientes com obesidade. Nas hemácias, foram medidos o transporte de L-arginina e a atividade da NOS e da arginase. Os níveis de aminoácidos e de marcadores inflamatórios (fibrinogênio e proteína C reativa) também foram medidos sistemicamente. Os resultados demonstram que o influxo de L-arginina via sistema y+L, a atividade da NOS e a produção de GMPc estão diminuídos nas plaquetas dos pacientes obesos em relação aos controles saudáveis, enquanto que não houve diferença na atividade da arginase. Além disso, a expressão das isoformas da NOS bem como a agregação plaquetária em plaquetas de pacientes com obesidade mostrou-se aumentada em relação aos controles. Nas hemácias destes pacientes, observou-se...

Obesity is a metabolic disorder of multifactorial etiology and high prevalence in Brazil, which can be defined as a body mass index (weight in kilograms divided by height in square meters) greater than or equal to 30 kg/m2, and that is independently associated with a high risk of cardiovascular morbidity and mortality due to atherothrombotic events. Nitric oxide (NO), a small gaseous molecule, is produced through the conversion of the cationic amino acid L-arginine to L-citrulline and NO in a reaction catalyzed by a family of enzymes called NO synthases (NOS) and it acts as a cardiovascular protector modulating, for example, the relaxation of vascular smooth muscle and the platelet function. The aim of this thesis was to assess the L-arginine-NO pathway, as well as to investigate platelet function, oxidative stress, and the arginase activity in patients with obesity. The L-arginine transport, the production of cyclic guanosine monophosphate (cGMP), the activity and expression of NOS isoforms (eNOS and iNOS), the arginase activity, oxidative stress (production of reactive oxygen species - ROS; superoxide dismutase activity - SOD, and catalase activity), and platelet function were evaluated in platelets from patients with obesity. In erythrocytes, the L-arginine transport and the activity of NOS and arginase were investigated. Systemic levels of amino acids and inflammatory markers (fibrinogen and C-reactive protein) were also investigated. The results demonstrated that L-arginine influx via y+L system, NOS activity, and cGMP levels were decreased in platelets from obese subjects compared to healthy controls, whereas no difference was observed in arginase activity. In addition, the expression of NOS isoforms and platelet aggregation in platelets from patients with obesity was increased in relation to controls. In erythrocytes from these patients, there were a higher influx of L-arginine via y+ and y+L system, and NOS activity, and no difference in arginase...

Arginase isoforms in frog and lizard tissues.

Isoforms of arginase in the liver and kidney tissues of the ureotelic frog (Rana tigerina) and uricotelic lizard (Calotes versicolor) were fractionated by DEAE-cellulose chromatography (pH 8.3). Four molecular forms, designated as A’1, A2, A3 and A4 based on the KCl concentration required for their elution from the ion-exchange column, were detected in lizard liver, while only two forms were found in lizard kidney (A3 and A4) and frog liver and kidney (A2 and A3). No major differences were found in the pH optimum, substrate affinity and molecular weight of the isoenzymes. The isoforms in lizard tissues were either totally unaffected or only partially immunoprecipitated by antibodies raised against rat liver and beef liver arginases, but those in frog tissues were significantly activated by the two antibodies. While the physiological importance of the presence of four isoforms in lizard liver remains enigmatic, different sets of isoenzymes were present in the liver of the two ureotelic vertebrates, rat and frog. Hence, it appeared that a given mode of nitrotelism was not associated with a specific set of isoenzymes. Also, the data were not consistent with the generally held view that a basic isoform of arginase served as a component of the urea cycle in liver and a neutral/slightly acidic form functions in the synthesis of proline, glutamate and polyamines in extra-hepatic tissues. The isoforms appeared to show considerable functional overlap.

Presencia del alelo T para el polimorfismo rs2781666 G>T del gen arginasa 1 constituye un factor protector contra enfermedad arterial coronaria / The presence of T allele for rs2781666 G>T common variant of arginase 1 gene constitutes a protector factor against coronary artery disease in Southern Chilean subjects

Introducción: Variaciones moleculares en el gen de la arginasa I, ARGl, podrían provocar un aumento de la expresión de la enzima o de su actividad, lo que puede llevar a una disfunción endotelial al disminuir la producción de óxido nítrico por parte de la eNOS. Así, el objetivo del presente estudio fue investigar la posible asociación del polimorfismo rs2781666 G>T y la presencia de enfermedad coronaria (confirmada con angiografía) en individuos de la región de La Araucanía. Material y Métodos: En el presente estudio, de tipo casos y controles, fueron evaluados 247 sujetos, con edades entre 30 y 74 años; 124 individuos pacientes con enfermedad arterial coronaria (casos) y 123 controles. La genotipificación del polimorfismo rs2781666 del gen ARGl fue realizada mediante PCR- RFLR Resultados: La frecuencia del genotipo homocigoto TT para el polimorfismo rs2781666 del gen ARGl fue de 6.5 por ciento en el grupo casos y 8 por ciento en el grupo control, difiriendo significativamente (p=0.032). La frecuencia relativa del alelo T también presentó diferencias significativas entre casos y controles (0.230 vs. 0.325, p=0.031). La OR relacionada al alelo mutado T fue de 0.63 (I.C. 95 por ciento, 0.43 - 0.94), confirmando la presencia de la asociación observada. Conclusión: Los resultados obtenidos sugieren que el polimorfismo rs2781666 G>T del gen ARGl confiere protección contra enfermedad coronaria en la población analizada. Sin embargo, este resultado debe ser replicado en otros grupos poblacionales de nuestro país.

Background: Recent data support a role for arginase 1 (ARG1) in the initiation, development, and complications of coronary artery disease. Thus, in the present study we investigated the possible association between the rs2781666 G>T variant of ARG1 and the presence of CAD confirmed by angiography in Chilean subjects. Methods: A total of 124 unrelated patients with diagnosis of CAD confirmed by angiography (stenosis > 70 percent) and 123 healthy controls (30 - 74 years old) were included in this study. The rs2781666 G>T variant of the ARG1 gene was evaluated by PCR-RFLR Results: The frequency of TT homozygous genotype in CAD patients was lower when compared to control group (6.5 percent vs. 8.0 percent, p=0.032). Similarly, the T allele frequency was different between CAD and control groups (0.230 vs. 0.325, p=0.031). The OR for CAD related to T allele was 0.64 (95 percent CI. = 0.43-0.94), con-firming the association founded. Conclusion: These findings suggest that the T allele for rs2781666 polymorphism of the ARG1 gene constitutes an inherited protective factor against CAD in Southern Chilean subjects.

novel mutation in ARG1 gene is responsible for arginase deficiency in an Asian family

Argininemia is a rare autosomal recessive metabolic disorder caused by a deficiency in the arginase enzyme, which is the final enzyme in the urea cycle and responsible for the hydrolysis of arginine to urea and ornithine. The disease becomes symptomatic during childhood and is characterized by progressive spastic quadriplegia, progressive mental impairment, growth retardation, and periodic episodes of hyperammonemia. At least 19 distinct mutations in the ARG1 gene have been identified indicating the molecular heterogeneity of this condition. We report a homozygous novel mutation [c.93 delG] in the ARG1 gene from 3 affected children of a Pakistani family living in the United Arab Emirates. The mutation is expected to lead to a frame shift after the thirtieth residue and a stop codon at residue 44 [p.T30fsX14]. Therefore, this mutation is expected to result in complete loss-of-function of the arginase enzyme and therefore is the mostly likely cause of argininemia in this family

Macrófagos e inducción de arginasa como mecanismo de evasión de parásitos / Macrophages and arginase induction as a mechanism for parasite escape

Aunque existen varios mecanismos inmunológicos para eliminar a los patógenos intracelulares, éstos han elaborado una variedad de estrategias para escapar de la respuesta del sistema inmune y asegurarse su supervivencia y replicación en el huésped. Algunos parásitos modulan la producción de numerosas moléculas tóxicas sintetizadas por el sistema inmune. Varios parásitos son altamente sensibles al óxido nítrico (ON) y sus derivados. El ON es producido en macrófagos (MΦ) luego de la estimulación con productos microbianos o con citoquinas. En el pasado, los MΦ se identificaban como células puramente inflamatorias (MΦ activados en forma clásica), capaces de secretar mediadores inflamatorios, actuar como células presentadoras de antígenos y matar patógenos intracelulares. Sin embargo, los MΦ activados representan un grupo más heterogéneo de células con distintos marcadores biológicos que pueden llevar a cabo diferentes funciones inmunológicas. Los MΦ activados alternativamente, fallan en producir ON en virtud de la inducción de la enzima arginasa y consecuentemente tienen disminuida su capacidad para matar patógenos intracelulares. Se ha comunicado la inducción de arginasa por parte de varios parásitos, por lo tanto este mecanismo podría favorecer su supervivencia en el huésped. En un modelo de infección con Trypanosoma cruzi, en nuestro grupo estudiamos la participación de arginasa y de las señales intracelulares involucradas en su inducción, durante la replicación de este parásito en los MΦ. La información obtenida a partir de nuestros trabajos permitiría comprender algunos mecanismos por los cuales distintas células del sistema inmune pueden ser programadas para favorecer el establecimiento de infecciones parasitarias crónicas.

Although there are several immunological mechanisms to eliminate the intracellular pathogens, they have elaborated a variety of strategies to escape of the immune response and to make possible their survival and replication in the host. Some parasites modulate the production of several toxic molecules synthesized by the immune system. Several parasites are highly sensitive to nitric oxide (ON) and their derivatives. ON is produced in macrophages (MΦ) after stimulation with microbial products or cytokines. In the past, M Φ were defined as inflammatory cells (classically activated MΦ), able to produce inflammatory mediators, to act like antigens presenting cells and to kill intracellular pathogens. Nevertheless, activated MΦ involve a more heterogeneous group of cells with different biological markers that can carry out different immunological functions. Alternatively activated MΦ fail to produce ON due to the arginase induction and consequently they have diminished their capacity to kill intracellular pathogens. It has been reported the induction of arginase by different parasites; therefore this mechanism could favor their survival in the host. In our group, we studied the participation of arginase in a model of Trypanosoma cruzi infection and the intracellular signals involved in the replication of this parasite in MΦ. The data obtained from our works would allow the understanding of some mechanisms by which cells can be programmed to favor the establishment of chronic parasitic infections.

Apoptotic mimicry: an altruistic behavior in host/Leishmania interplay

Apoptosis is the most common phenotype observed when cells die through programmed cell death. The morphologic and biochemical changes that characterize apoptotic cells depend on the activation of a diverse set of genes. Apoptosis is essential for multicellular organisms since their development and homeostasis are dependent on extensive cell renewal. In fact, there is strong evidence for the correlation between the emergence of multicellular organisms and apoptosis during evolution. On the other hand, no obvious advantages can be envisaged for unicellular organisms to carry the complex machinery required for programmed cell death. However, accumulating evidence shows that free-living and parasitic protozoa as well as yeasts display apoptotic markers. This phenomenon has been related to altruistic behavior, when a subpopulation of protozoa or yeasts dies by apoptosis, with clear benefits for the entire population. Recently, phosphatidylserine (PS) exposure and its recognition by a specific receptor (PSR) were implicated in the infectivity of amastigote forms of Leishmania, an obligatory vertebrate intramacrophagic parasite, showing for the first time that unicellular organisms use apoptotic features for the establishment and/or maintenance of infection. Here we focus on PS exposure in the outer leaflet of the plasma membrane - an early hallmark of apoptosis - and how it modulates the inflammatory activity of phagocytic cells. We also discuss the possible mechanisms by which PS exposure can define Leishmania survival inside host cells and the evolutionary implications of apoptosis at the unicellular level.

Modulation of mRNA levels of liver arginase by insulin and vanadate in experimental diabetes.

This work was carried out to study the modulation of arginase expression in experimental diabetes. Here, we have demonstrated that liver arginase activity and mRNA levels increased significantly in diabetic condition. Insulin treatment reverses the increased activity and mRNA levels nearly to the control values. The reversal effects of vanadate are found to be similar to that of insulin and this observation further reiterates the insulin-like effects of vanadate. ELISA and slot blot assay observations are consistent with biochemical measurements of enzyme activity. These results show an increase in arginase activity and mRNA levels in diabetes and decrease in treated animals may be due to the transcriptional regulation of arginase gene.

Alterations in kidney enzyme pattern in acute hypervitaminosis A

The relation of excessive doses of vitamin A with various kidney pathologies is well known however, information concerning the relation of kidney enzyme activity with acute hypervitaminosis A is rather scarce. In this study we describe the kidney enzymatic alterations observed in rats that received daily intramuscular injectiosn of 10.000, 30.000, 50.000 and 100.000IU of vitamin A palmitate (VA) during seven days (TREATED GROUPS). A comparison is made with the enzyme activity in healthy rats pairfed and treated with sodium palmitte by intramuscular injection (CONTROL GROUP). The treated rats showed a proportional increase (<0.05) in activity of acid maltase, transaminases or aminotransferase (GOT and GPT), alkaline phosphatase (ALP) and acid protease with all doses of VA administered, Amylase, lipase and arginase tend to decrease (p<0.05) in activity only with doses of 50.000 and 100.000 I.U. of VA. Several factors are responsible for these findings, such as kidney necrosis due to release of lysosomal acid hydrolases produced by hypervitaminosis A.

Arginase activity of Bufo arenarum embryos is sensitive to external osmotic pressure

We investigated the impact of environmental osmotic stress on the arginase activity if Bufo arenarum embryos. The activity at the first developmental stages was not sensitive to extreme variations of osmotic pressure of the environment. Later, at gill circulation, opercular fold and right operculum stages, the enzyme activity of embryos developed in concentrated solutions decreased significantly with respect to control. At complete operculum stage, the arginase activity increased 1.3-2.5 fold in all conditions, and was significantly higher in embryos grown in distilled water than in control animals

Arginase activity in Bufo arenarum embryos

The evolution of arginase activity during development of Bufo arenarum embryos was studied. The enzyme activity was detected after the neural groove stage, being low at the following early stages and increasing progressively until the end of the embryonic development. Arginase activity was first found in the neurula stage, when an outline of basic structures for renal and hepatic function is present. The activity increased two- or three-fold at the beginning of the larval stages

Arginine protection against ammonia toxicity in exhausted rat.

Arginine administration (5 m moles/kg/day) to albino rats for 7 days, revealed that this vital basic amino acid possesses latent potentiality for the accentuation of urea cycle or at least for arginase activity. The mitigation of ammonia toxicity was observed to be more effective in the case of gastrocnemius and red vastus as compared to white vastus. Further, ammonia and lactate levels were also decreased by arginine in blood and thereby delaying the onset of fatigue by preventing ammonotoxemia and lactic acidemia.

A biphasic compartmentation of neuro-transmission associated metabolic patterns during electro-induced axoplasmic transport in sheep medulla oblongata.

In the sheep medulla oblongata, on the induction of polarity by the applied voltage gradient of direct current along the length, the enzymes such as acetylcholinesterase and glutamate dehydrogenase showed anodal transport while the enzyme arginase showed cathodal transport indicating the possession of negative and positive charge densities on the enzymes. These studies indicated that the glutamate bound metabolism, one towards ammonia formation and the other towards the energy production and neural transmission, have opposed electro-characteristics. The acetylcholinesterase system had anodal characteristics coupled to the glutamate dehydrogenase patterns. The existence of two charge based compartmentation is envisaged in the neural tissue.