RESUMO
Zinc is the catalytic component of proteins that regulate responses to DNA damage, intracellular signaling enzymes, and matrix metalloproteinases, which are important proteins in carcinogenesis. The objective of this review is to bring current information on the participation of zinc and matrix metalloproteinases types 2 and 9 in mechanisms involved in the pathogenesis of breast cancer. We conducted a literature review, in consultation with the PubMed, Lilacs, and Scielo databases. The zinc and cysteine residues are structural elements shared by all members of the family of matrix metalloproteinases, and these proteins appear to be involved in the propagation of various types of neoplasms, including breast cancer. Moreover, transported zinc is likely to be used for the metalation of the catalytic domain of the newly synthesized metalloproteinases before the latter are secreted. Accordingly, increase in zinc concentrations in cellular compartments and the reduction of this trace element in the blood of patients with breast cancer appear to alter the activity of metalloproteinases 2 and 9, contributing to the occurrence of malignancy. Thus, it is necessary to carry out further studies with a view to clarify the role of zinc and metalloproteinases 2 and 9 in the pathogenesis of breast cancer.
Assuntos
Neoplasias da Mama/etiologia , Metaloproteinase 2 da Matriz/fisiologia , Metaloproteinase 9 da Matriz/fisiologia , Zinco/fisiologia , Neoplasias da Mama/enzimologia , Neoplasias da Mama/metabolismo , Feminino , Humanos , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Zinco/metabolismoRESUMO
Summary Zinc is the catalytic component of proteins that regulate responses to DNA damage, intracellular signaling enzymes, and matrix metalloproteinases, which are important proteins in carcinogenesis. The objective of this review is to bring current information on the participation of zinc and matrix metalloproteinases types 2 and 9 in mechanisms involved in the pathogenesis of breast cancer. We conducted a literature review, in consultation with the PubMed, Lilacs, and Scielo databases. The zinc and cysteine residues are structural elements shared by all members of the family of matrix metalloproteinases, and these proteins appear to be involved in the propagation of various types of neoplasms, including breast cancer. Moreover, transported zinc is likely to be used for the metalation of the catalytic domain of the newly synthesized metalloproteinases before the latter are secreted. Accordingly, increase in zinc concentrations in cellular compartments and the reduction of this trace element in the blood of patients with breast cancer appear to alter the activity of metalloproteinases 2 and 9, contributing to the occurrence of malignancy. Thus, it is necessary to carry out further studies with a view to clarify the role of zinc and metalloproteinases 2 and 9 in the pathogenesis of breast cancer.
Resumo O zinco é componente catalítico de proteínas que regulam respostas a danos no DNA, enzimas de sinalização intracelular e metaloproteinases de matriz, proteínas importantes na carcinogênese. O objetivo desta revisão é trazer informações atualizadas sobre a participação do zinco e das metaloproteinases de matriz dos tipos 2 e 9 em mecanismos envolvidos na patogênese do câncer de mama. Realizou-se um levantamento bibliográfico, mediante consulta às bases de dados PubMed, Scielo e Lilacs. O zinco e os resíduos de cisteína são elementos estruturais compartilhados por todos os membros da família das metaloproteinases de matriz, as quais parecem estar envolvidas na propagação de vários tipos de neoplasias, incluindo o câncer de mama. Além disso, é provável que o zinco transportado seja utilizado para metalação do domínio catalítico das metaloproteinases recentemente sintetizadas antes de serem segregadas. Nesse sentido, o aumento das concentrações de zinco em compartimentos celulares e a redução desse oligoelemento no sangue de pacientes com câncer de mama parecem alterar a atividade das metaloproteinases 2 e 9, contribuindo para a ocorrência de tumor maligno. Assim, faz-se necessária a realização de novos estudos na perspectiva de esclarecer o papel do zinco e das metaloproteinases 2 e 9 na patogênese do câncer de mama.
Assuntos
Humanos , Feminino , Zinco/fisiologia , Neoplasias da Mama/etiologia , Metaloproteinase 2 da Matriz/fisiologia , Metaloproteinase 9 da Matriz/fisiologia , Zinco/metabolismo , Neoplasias da Mama/enzimologia , Neoplasias da Mama/metabolismo , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismoRESUMO
Zinc (Zn) is important in a number of processes related to insulin secretion and insulin activity in peripheral tissues, making this element an interesting potential co-adjuvant in the treatment of patients with type 2 diabetes (T2D). This issue has been matter of interest in recent years. The available evidence is analyzed in this review. Information from epidemiologic studies evaluating the relationship between Zn and T2D is inconsistent. Furthermore, few studies examined the association between Zn status and insulin action and/or glucose homeostasis. In terms of usefulness of Zn as a preventive agent for T2D development, information is insufficient to reach firm conclusions. Results from Zn supplementation trials found some positive effects only in those with initial sub normal Zn status in a significant proportion of individuals. In conclusion, the effect of Zn on patients with type 2 diabetes is still an open question, and better study designs are needed to clarify the real impact and characteristics of the Zn-diabetes interaction.
Assuntos
Diabetes Mellitus Tipo 2/prevenção & controle , Zinco/administração & dosagem , Diabetes Mellitus Tipo 2/sangue , Suplementos Nutricionais , Hemoglobinas Glicadas/análise , Humanos , Zinco/fisiologiaRESUMO
OBJETIVO: Investigar a influência de anticoncepcionais hormonais (ACH) orais em indicadores bioquímicos relacionados à utilização metabólica e distribuição de zinco e ao turnover ósseo em mulheres adultas jovens.MÉTODOS: Estudo transversal. Amostras de sangue e urina de não usuárias (-ACH; controle; n=69) e usuárias há pelo menos três meses de contraceptivos hormonais orais (+ACH; n=62) foram coletadas em condições padronizadas. Foram analisados os indicadores de homeostase de zinco e de turnoverósseo em soro ou plasma (zinco total e nas frações de albumina e α2-macroglobulina, albumina e atividade de fosfatase alcalina total e de origem óssea), em eritrócitos (zinco e metalotioneína) e em urina (zinco, cálcio e hidroxiprolina). Ingestões habituais de zinco e cálcio foram avaliadas por questionário de frequência de consumo.RESULTADOS: A ingestão alimentar de zinco foi semelhante nos grupos e, em média, acima do recomendado, enquanto que a ingestão de cálcio foi similarmente subadequada em +ACH e -ACH. Comparadas às controles, as +ACH apresentaram menores concentrações de zinco em soro, total e ligado à α2-macroglobulina (11 e 28,5%, respectivamente, p<0,001); albumina em soro (13%, p<0,001); atividade de fosfatase alcalina em plasma, total e de origem óssea (13 e 18%, respectivamente, p<0,05); metalotioneína em eritrócitos (13%, p<0,01) e zinco urinário (34%, p<0,05).CONCLUSÕES: O uso de ACH reduz o zinco sérico, altera a distribuição de zinco nas principais proteínas ligantes do soro com possíveis efeitos na captação tecidual, aumenta a retenção de zinco no organismo e reduz o turnover ósseo. O uso prolongado de ACH poderia levar a menor pico de massa óssea e/ou prejudicar a manutenção de massa óssea em mulheres jovens, principalmente com ingestão marginal de cálcio. Os efeitos de ACH verificados foram mais evidentes nas mulheres <25 anos de idade e nas nulíparas, as quais merecem especial atenção em estudos posteriores.
PURPOSE: To investigate the influence of the use of oral hormonal contraceptive agents (OCA) on the biochemical indices related to metabolic zinc utilization and distribution, and to bone turnover in young adult women.METHODS: Cross-sectional study. Blood and urine samples from non-users (-OCA; control; n=69) and users of hormonal contraceptives for at least 3 months (+OCA; n=62) were collected under controlled conditions. Indices of zinc homeostasis and of bone turnover were analyzed in serum or plasma (total, albumin-bound and α2-macroglobulin-bound zinc, albumin and total and bone alkaline phosphatase activity), in erythrocytes (zinc and metallothionein) and in urine (zinc, calcium and hydroxyproline). The habitual zinc and calcium intakes were evaluated by a food frequency questionnaire.RESULTS: Dietary zinc intake was similar in both groups and on average above recommended values, whereas calcium intake was similarly sub-adequate in +OCA and -OCA. Compared to controls, +OCA had lower concentrations of total and α2-macroglobulin-bound zinc (11 and 28.5%, respectively, p<0.001), serum albumin (13%, p<0.01), total and bone-specific alkaline phosphatase activity (13 and 18%, respectively, p<0.05), erythrocyte metallothionein (13%, p<0.01), and, urinary zinc (34%, p<0.05).CONCLUSIONS: OCA use decreases serum zinc, alters zinc distribution in major serum fractions with possible effects on tissue uptake, enhances zinc retention in the body and decreases bone turnover. Prolonged OCA use may lead to lower peak bone mass and/or to impaired bone mass maintenance in young women, particularly in those with marginal calcium intake. The observed OCA effects were more evident in women younger than 25 years and in nulliparous women, deserving special attention in future studies.
Assuntos
Humanos , Feminino , Adulto , Adulto Jovem , Remodelação Óssea/efeitos dos fármacos , Anticoncepcionais Orais Hormonais/farmacologia , Homeostase/efeitos dos fármacos , Zinco/fisiologia , Anticoncepcionais , Estudos TransversaisRESUMO
PURPOSE: To investigate the influence of the use of oral hormonal contraceptive agents (OCA) on the biochemical indices related to metabolic zinc utilization and distribution, and to bone turnover in young adult women. METHODS: Cross-sectional study. Blood and urine samples from non-users (-OCA; control; n=69) and users of hormonal contraceptives for at least 3 months (+OCA; n=62) were collected under controlled conditions. Indices of zinc homeostasis and of bone turnover were analyzed in serum or plasma (total, albumin-bound and α2-macroglobulin-bound zinc, albumin and total and bone alkaline phosphatase activity), in erythrocytes (zinc and metallothionein) and in urine (zinc, calcium and hydroxyproline). The habitual zinc and calcium intakes were evaluated by a food frequency questionnaire. RESULTS: Dietary zinc intake was similar in both groups and on average above recommended values, whereas calcium intake was similarly sub-adequate in +OCA and -OCA. Compared to controls, +OCA had lower concentrations of total and α2-macroglobulin-bound zinc (11 and 28.5%, respectively, p<0.001), serum albumin (13%, p<0.01), total and bone-specific alkaline phosphatase activity (13 and 18%, respectively, p<0.05), erythrocyte metallothionein (13%, p<0.01), and, urinary zinc (34%, p<0.05). CONCLUSIONS: OCA use decreases serum zinc, alters zinc distribution in major serum fractions with possible effects on tissue uptake, enhances zinc retention in the body and decreases bone turnover. Prolonged OCA use may lead to lower peak bone mass and/or to impaired bone mass maintenance in young women, particularly in those with marginal calcium intake. The observed OCA effects were more evident in women younger than 25 years and in nulliparous women, deserving special attention in future studies.
Assuntos
Remodelação Óssea/efeitos dos fármacos , Anticoncepcionais Orais Hormonais/farmacologia , Homeostase/efeitos dos fármacos , Zinco/fisiologia , Adulto , Anticoncepcionais , Estudos Transversais , Feminino , Humanos , Adulto JovemRESUMO
We evaluate the simultaneous use of Sr: Ca and Zn: Ca ratios of the sagitta otolith as a potential indicator of the habitat of Percophis brasiliensis along a latitudinal gradient in the southwestern Atlantic Ocean (34-42ºS and 51-67ºW), in order to reliably identify fish stocks. Fish were collected in three sampling sites: Argentine-Uruguayan Common Fishing Zone (AUCFZ), El Rincón (ER) and San Matías Gulf (SMG). The otolith Sr:Ca and Zn:Ca ratios were determined by ICP-OES and EDTA volumetric method. The otolith Sr:Ca ratio was similar in the three sampling sites, while the Zn:Ca ratio was significantly higher in AUCFZ than in ER and SMG for all age groups. The discriminant analysis showed an association between the otolith Sr:Ca and Zn:Ca ratios from ER and SMG. Present results suggest the potential occurrence of two fish stocks of P. brasiliensis in the study area.
Evaluamos el uso simultáneo de las relaciones Sr:Ca y Zn:Ca de los otolitos sagittae como un potencial indicador de hábitat de Percophis brasiliensis a lo largo de un gradiente longitudinal el Atlántico sudoccidental (34-42ºS - 51-67ºW) con el fin de contribuir a la identificación de los stocks pesqueros. Los peces fueron capturados en tres sitios de muestreo: Zona Común de Pesca Argentina-Uruguaya (ZCPAU), El Rincón (ER) y el Golfo San Matías (GSM). Las relaciones Sr:Ca y Zn:Ca se determinaron por ICP-OES y por titulación con EDTA. La relación Sr:Ca fue similar en los tres sitios de muestreo. La relación Zn:Ca fue mayor en la ZCPAU que en las demás areas (ER y GSM) para todos los rangos de edad. El análisis discriminante mostró una asociación entre las relaciones Sr:Ca y Zn:Ca de ER y GSM. Los resultados de este trabajo sugieren la presencia de al menos dos stocks de P. brasiliensis en el aérea de estudio.
Assuntos
Animais , Cálcio/fisiologia , Estrôncio/fisiologia , Membrana dos Otólitos/química , Perciformes/anatomia & histologia , Zinco/fisiologia , Ecossistema/efeitos adversosRESUMO
We evaluate the simultaneous use of Sr: Ca and Zn: Ca ratios of the sagitta otolith as a potential indicator of the habitat of Percophis brasiliensis along a latitudinal gradient in the southwestern Atlantic Ocean (34-42ºS and 51-67ºW), in order to reliably identify fish stocks. Fish were collected in three sampling sites: Argentine-Uruguayan Common Fishing Zone (AUCFZ), El Rincón (ER) and San Matías Gulf (SMG). The otolith Sr:Ca and Zn:Ca ratios were determined by ICP-OES and EDTA volumetric method. The otolith Sr:Ca ratio was similar in the three sampling sites, while the Zn:Ca ratio was significantly higher in AUCFZ than in ER and SMG for all age groups. The discriminant analysis showed an association between the otolith Sr:Ca and Zn:Ca ratios from ER and SMG. Present results suggest the potential occurrence of two fish stocks of P. brasiliensis in the study area.(AU)
Evaluamos el uso simultáneo de las relaciones Sr:Ca y Zn:Ca de los otolitos sagittae como un potencial indicador de hábitat de Percophis brasiliensis a lo largo de un gradiente longitudinal el Atlántico sudoccidental (34-42ºS - 51-67ºW) con el fin de contribuir a la identificación de los stocks pesqueros. Los peces fueron capturados en tres sitios de muestreo: Zona Común de Pesca Argentina-Uruguaya (ZCPAU), El Rincón (ER) y el Golfo San Matías (GSM). Las relaciones Sr:Ca y Zn:Ca se determinaron por ICP-OES y por titulación con EDTA. La relación Sr:Ca fue similar en los tres sitios de muestreo. La relación Zn:Ca fue mayor en la ZCPAU que en las demás areas (ER y GSM) para todos los rangos de edad. El análisis discriminante mostró una asociación entre las relaciones Sr:Ca y Zn:Ca de ER y GSM. Los resultados de este trabajo sugieren la presencia de al menos dos stocks de P. brasiliensis en el aérea de estudio.(AU)
Assuntos
Animais , Membrana dos Otólitos/química , Cálcio/fisiologia , Estrôncio/fisiologia , Zinco/fisiologia , Perciformes/anatomia & histologia , Ecossistema/efeitos adversosRESUMO
OBJECTIVES: To highlight the main aspects related to the population diagnosis of zinc nutritional status, describe the estimates of zinc deficiency magnitude in Brazil and emphasize the main interventions for improving zinc nutritional status. Data source: Publications were selected in SciELO, LILACS and MEDLINE/PUBMED databases, using the search terms "zinc deficiency e Brazil" and "diet supplementation and zinc and Brazil". Data synthesis: The use of a set of three indicators has been recommended to obtain the best estimate of zinc deficiency risk: i) biochemical indicator (serum zinc deficiency), ii) dietary indicator (inadequate zinc intake), iii) functional indicator (height-for-age deficit in children). According to these indicators, Brazil is a country with moderate zinc deficiency risk. The main strategies that can be implemented to improve zinc nutritional state in populations or population subgroups in risk are diet supplementation, fortification and modification/diversification. CONCLUSIONS: It is estimated that zinc deficiency is a public health problem in Brazil. The planning of new research becomes important for a better understanding of the risk factors, the identification of population groups with more vulnerability and the selection of appropriate intervention strategies
OBJETIVOS: Destacar os principais aspectos relacionados ao diagnóstico populacional do estado nutricional relativo ao zinco; descrever as estimativas sobre a magnitude da deficiência de zinco no Brasil; e ressaltar as principais intervenções para a melhoria do estado nutricional relativo ao zinco. Fonte de dados: Foram selecionadas publicações nas bases de dados SciELO, LILACS e MEDLINE/PUBMED, utilizando-se os termos de busca "deficiência de zinco e Brasil" e "suplementação dietética e zinco e Brasil". Síntese dos dados: Recomenda-se a utilização de um conjunto de três indicadores para obter a melhor estimação do risco de deficiência de zinco: i) indicador bioquímico (deficiência de zinco sérico), ii) indicador dietético (ingestão dietética de zinco inadequada), iii) indicador funcional (déficit de estatura para idade em crianças). Segundo esses indicadores, o Brasil se mostra como um país com risco moderado de deficiência de zinco. As principais estratégias que podem ser implementadas para melhorar o estado nutricional de zinco nas populações ou subgrupos populacionais em risco são a suplementação, a fortificação e a modificação/diversificação da dieta. CONCLUSÕES: Estima-se a deficiência de zinco como problema de saúde pública no Brasil. O planejamento de novas pesquisas se faz importante para um melhor entendimento dos fatores de risco, para a identificação dos segmentos da população de maior vulnerabilidade e para a seleção de estratégias de intervenção apropriadas
Assuntos
Humanos , Masculino , Feminino , Deficiências Nutricionais , Programas e Políticas de Nutrição e Alimentação , Zinco/fisiologia , Zinco/uso terapêuticoRESUMO
Minerals are essential nutrients for the body, are of inorganic nature which gives them the characteristic of being resistant to heat, are involved in a lot of chemical reactions in metabolism, regulating electrolyte balance, in maintaining bone, in the process of blood clotting and the transmission of nerve impulses, particularly its role as enzyme cofactors confers a key role in various physiological processes. Glucose homeostasis involves a fine coordination of events where hormonal control by insulin plays a key role. However, the role of minerals like magnesium, zinc, chromium, iron and selenium in the diabetes is less obvious and in some cases may be controversial. This review shows the knowledge of these five elements and their correlation with diabetes.
Los minerales son nutrientes esenciales para el organismo, de naturaleza inorgánica que les confiere, entre otras características, ser resistentes al calor, participan en diversas reacciones químicas del metabolismo en donde regulan el equilibrio hidroelectrolítico, el mantenimiento óseo, en la trasmisión de los impulsos nerviosos, y durante el proceso de coagulación sanguínea, particularmente por su función como cofactores enzimáticos, tienen un papel clave en varios procesos fisiológicos. La homeostasis de la glucosa involucra una fina coordinación de eventos en donde el control hormonal por la insulina tiene un papel primordial. Sin embargo, la función de los minerales, como el magnesio, el zinc, el cromo, el hierro y el selenio en la diabetes es menos evidente y puede ser, en algún caso, controversial. Esta revisión muestra el conocimiento acerca de estos cinco elementos y su correlación con la diabetes.
Assuntos
Diabetes Mellitus/metabolismo , Micronutrientes/fisiologia , Minerais/metabolismo , Animais , Cromo/deficiência , Cromo/fisiologia , Cromo/uso terapêutico , Diabetes Mellitus Experimental/metabolismo , Glucose/metabolismo , Homeostase , Humanos , Resistência à Insulina , Ferro/fisiologia , Ferro/uso terapêutico , Deficiências de Ferro , Magnésio/fisiologia , Magnésio/uso terapêutico , Deficiência de Magnésio/complicações , Deficiência de Magnésio/metabolismo , Síndrome Metabólica/metabolismo , Micronutrientes/uso terapêutico , Minerais/uso terapêutico , Estresse Oxidativo , Selênio/deficiência , Selênio/fisiologia , Selênio/uso terapêutico , Zinco/deficiência , Zinco/fisiologia , Zinco/uso terapêuticoRESUMO
BACKGROUND: Type 2 diabetes is highly prevalent in populations having high rates of overweight and obesity. It is a chronic condition responsible for long-term severe dysfunction of several organs, including the kidneys, heart, blood vessels, and eyes. Although there are a number of pharmacologic products in the market to treat insulin resistance and impaired insulin secretion--the most prominent features of this disease--interventions directed at preserving the integrity and function of beta-cells in the long term are less available. The use of some nutrients with important cellular protective roles that may lead to a preservation of beta-cells has not been fully tested; among these, zinc may be an interesting candidate. OBJECTIVE: To assess the potential of zinc supplementation as coadjuvant to diabetes therapy. METHODS: This article reviews the available information on the use of zinc as part of diabetes therapy. RESULTS: Cellular and animal models provide information on the insulin mimetic action of zinc, as well as its role as a regulator of oxidative stress, inflammation, apoptosis, and insulin secretion. Zinc supplementation studies in humans are limited, although some positive effects have been reported; mainly, a modest but significant reduction in fasting glucose and a trend to decreased glycated hemoglobin (HbA1c). CONCLUSIONS: Zinc supplementation may have beneficial effects on glycemic control. Nevertheless, among the studies considered, the vast majority lasted for 6 months or less, suggesting the importance of conducting long-duration studies given the characteristics of type 2 diabetes as a chronic disease.
Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Zinco/uso terapêutico , Animais , Apoptose , Glicemia/análise , Diabetes Mellitus Tipo 2/complicações , Suplementos Nutricionais , Humanos , Inflamação , Insulina/metabolismo , Resistência à Insulina , Secreção de Insulina , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/fisiologia , Estresse Oxidativo , Zinco/administração & dosagem , Zinco/fisiologiaRESUMO
Exposure to arsenic via drinking water is considered as a worldwide problem. Studies have shown that arsenic exposure during pregnancy affects embryogenesis and offspring development in rats and mice. Zinc as a micronutrient regulates many physiological functions, including an antioxidative role under various toxic conditions. However, studies on the perinatal protective effect of zinc on offspring need further attention. The present study was designed to evaluate the potential protective role of zinc in mitigating the adverse effects in the offspring of arsenic exposure during pregnancy. The arsenic (40mg/kg body weight) and zinc (4% w/v) doses formed the only drinking fluid source for the experimental groups of dams during the perinatal period of the experiment. The early development of sensory motor coordination reflexes together with morphological development in the male pups was measured during the weaning period. In adolescence, the offspring were tested for their motor behavior. The enzyme γ-glutamyl transferase (γ-GT) and the oxidative stress indices like reduced glutathione (GSH) and lipid peroxidation (TBARS) were also estimated in the serum of the young adult male mice. Perinatal arsenic exposure caused depletion in body weight gain, delay in morphological development and retardation in the development of all sensory motor reflexes of the pups. In young adults, significant decrease in motor behavior with significant decrease in GSH level in the serum was observed. On the other hand, γ-GT and TBARS were significantly increased in the serum due to arsenic treatment. However, animals exposed to arsenic in the presence of zinc showed a remarkable ameliorating effect of zinc on all observed teratological and biochemical arsenic toxicity in male offspring. It was observed that zinc has an antioxidative role in the perinatal toxicity of arsenic. It is concluded from the present study that zinc consumed during the perinatal period of pregnancy can ameliorate the possible toxicities of arsenic exposure in the offspring by acting as an ameliorative supplement.
Assuntos
Intoxicação por Arsênico/congênito , Arsênio/toxicidade , Feto/anormalidades , Atividade Motora/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Zinco/fisiologia , Animais , Antioxidantes/administração & dosagem , Feminino , Glutationa/sangue , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Exposição Materna , Camundongos , Gravidez , gama-Glutamiltransferase/sangueRESUMO
Zinc has become a prominent nutrient of clinical and public health interest in the new millennium. Functions and actions for zinc emerge as increasingly ubiquitous in mammalian anatomy, physiology and metabolism. There is undoubtedly an underpinning in fundamental biology for all of the aspects of zinc in human health (clinical and epidemiological) in pediatric and public health practice. Unfortunately, basic science research may not have achieved a full understanding as yet. As a complement to the applied themes in the companion articles, a selection of recent advances in the domains homeostatic regulation and transport of zinc is presented; they are integrated, in turn, with findings on genetic expression, intracellular signaling, immunity and host defense, and bone growth. The elements include ionic zinc, zinc transporters, metallothioneins, zinc metalloenzymes and zinc finger proteins. In emerging basic research, we find some plausible mechanistic explanations for delayed linear growth with zinc deficiency and increased infectious disease resistance with zinc supplementation.
Assuntos
Suplementos Nutricionais , Zinco/fisiologia , Transporte Biológico , Desenvolvimento Ósseo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Regulação da Expressão Gênica , Homeostase , Humanos , Imunidade , Metalotioneína/genética , Metalotioneína/metabolismo , Transdução de Sinais , Fatores de Transcrição , Zinco/química , Zinco/deficiência , Dedos de ZincoRESUMO
Exposure to arsenic via drinking water is considered as a worldwide problem. Studies have shown that arsenic exposure during pregnancy affects embryogenesis and offspring development in rats and mice. Zinc as a micronutrient regulates many physiological functions, including an antioxidative role under various toxic conditions. However, studies on the perinatal protective effect of zinc on offspring need further attention. The present study was designed to evaluate the potential protective role of zinc in mitigating the adverse effects in the offspring of arsenic exposure during pregnancy. The arsenic (40mg/kg body weight) and zinc (4% w/v) doses formed the only drinking fluid source for the experimental groups of dams during the perinatal period of the experiment. The early development of sensory motor coordination reflexes together with morphological development in the male pups was measured during the weaning period. In adolescence, the offspring were tested for their motor behavior. The enzyme γ-glutamyl transferase (γ-GT) and the oxidative stress indices like reduced glutathione (GSH) and lipid peroxidation (TBARS) were also estimated in the serum of the young adult male mice. Perinatal arsenic exposure caused depletion in body weight gain, delay in morphological development and retardation in the development of all sensory motor reflexes of the pups. In young adults, significant decrease in motor behavior with significant decrease in GSH level in the serum was observed. On the other hand, γ-GT and TBARS were significantly increased in the serum due to arsenic treatment. However, animals exposed to arsenic in the presence of zinc showed a remarkable ameliorating effect of zinc on all observed teratological and biochemical arsenic toxicity in male offspring. It was observed that zinc has an antioxidative role in the perinatal toxicity of arsenic. It is concluded from the present study that zinc consumed during the perinatal period of pregnancy can ameliorate the possible toxicities of arsenic exposure in the offspring by acting as an ameliorative supplement.
Assuntos
Animais , Feminino , Masculino , Camundongos , Gravidez , Intoxicação por Arsênico/congênito , Arsênio/toxicidade , Feto/anormalidades , Atividade Motora/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Zinco/fisiologia , Antioxidantes/administração & dosagem , Glutationa/sangue , Peroxidação de Lipídeos/efeitos dos fármacos , Exposição Materna , gama-Glutamiltransferase/sangueRESUMO
Deficiencies of nutrients such as amino acids, vitamins, lipids, and trace elements during gestation and early infanthood have strong deleterious effects on the development of the limbic system; these effects may be irreversible, even when adequate supplementation is provided at later developmental stages. Recent advances in the neurochemistry of biometals are increasingly establishing the roles of the trace elements iron, copper, zinc, and selenium in a variety of cell functions and are providing insight into the repercussions of deficiencies and excesses of these elements on the development of the central nervous system, especially the limbic system. The limbic system comprises diverse areas with high metabolic demands and differential storage of iron, copper, zinc, and selenium. This review summarizes available evidence suggesting the involvement of these trace elements in pathological disorders of the limbic system.
Assuntos
Encefalopatias/etiologia , Sistema Límbico/efeitos dos fármacos , Sistema Límbico/crescimento & desenvolvimento , Oligoelementos/sangue , Oligoelementos/deficiência , Encefalopatias/sangue , Cobre/sangue , Cobre/deficiência , Cobre/fisiologia , Humanos , Ferro/sangue , Ferro/fisiologia , Deficiências de Ferro , Sistema Límbico/fisiologia , Fenômenos Fisiológicos da Nutrição/efeitos dos fármacos , Fenômenos Fisiológicos da Nutrição/fisiologia , Necessidades Nutricionais , Selênio/sangue , Selênio/deficiência , Selênio/fisiologia , Zinco/sangue , Zinco/deficiência , Zinco/fisiologiaRESUMO
Son cuatro los nutrientes en que su deficiencia es importante en niños: hierro, yodo, vitamina A y zinc. Más o menos se calcula que hay 2 billones de personas en el mundo con algún grado de déficit de zinc. Los pacientes que están en riesgo de presentar deficiencias de zinc son los recién nacidos con bajo peso al nacimiento, bien sea prematuros, desnutridos in útero o hijos de madres desnutridas, en los cuales sus depósitos están reducidos. A diferencia de otros oligoelementos o micronutrientes, determinar el estado de déficit no es fácil. Los niveles séricos de zinc, están influenciados por factores no dietarios como infección, estrés o actividad física extenuante; al igual que por el ciclo circadiano.
Four nutrient deficiency that is important in children, iron, iodine, vitamin A and zinc. More or less it is estimated that 2 billion people in the world with some degree of zinc deficiency. Patients who are at risk for zinc deficiency are infants with low birth weight, either premature or malnourished in utero, undernourished mothers, in which their deposits are reduced. Unlike other trace elements or micronutrients, determine the deficit is not easy. Serum levels of zinc are not influenced by dietary factors such as infection, stress or strenuous physical activity, as well as by the circadian cycle.
Assuntos
Humanos , Masculino , Feminino , Zinco/administração & dosagem , Zinco/classificação , Zinco , Zinco/deficiência , Zinco/efeitos adversos , Zinco/farmacologia , Zinco/fisiologia , Zinco/metabolismo , Zinco/provisão & distribuição , Zinco , Ferro/administração & dosagem , Ferro/classificação , Ferro/farmacologia , Ferro/provisão & distribuição , Ferro , Transtornos da Nutrição Infantil/classificação , Transtornos da Nutrição Infantil/complicações , Transtornos da Nutrição Infantil/diagnóstico , Transtornos da Nutrição Infantil/epidemiologia , Transtornos da Nutrição Infantil/fisiopatologia , Transtornos da Nutrição Infantil/prevenção & controle , Transtornos da Nutrição Infantil/psicologia , Transtornos da Nutrição Infantil/reabilitaçãoAssuntos
Masculino , Feminino , Humanos , Compostos de Zinco , Ciências da Nutrição , Zinco/fisiologia , Zinco/metabolismo , Zinco/química , Composição de AlimentosRESUMO
Este trabalho visa a contribuir com informações sobre a relação entre exercício físico, estresse oxidativo e zinco. A formação de espécies reativas de oxigênio durante o exercício pode contribuir para danos tissulares e celulares, prejudicando o desempenho do atleta. Podem amenizar esses efeitos alguns minerais, como o zinco, que atuam como cofator da enzima superóxido dismutase e na regulação da síntese da metalotioneína, proteínas importantes no sistema de defesa antioxidante. No exercício físico, ocorrem distúrbios na compartimentalização do zinco, com alterações da concentração desse mineral em compartimentos celulares. No entanto, os mecanismos envolvidos no comportamento metabólico do zinco bem como a participação do mineral na melhora do desempenho físico ainda não estão totalmente esclarecidos. Dessa forma, conclui-se que a distribuição do zinco em organismos submetidos ao estresse oxidativo e os efeitos da deficiência desse mineral na capacidade antioxidante durante o exercício ainda devem ser pesquisados mais profundamente.
The aim of this study is to provide information about the association between physical exercise, oxidative stress and zinc. The formation of reactive oxygen species during exercise may contribute to tissue and cell damage, hindering athletes' performance. Some minerals, such as zinc, mitigate these effects by acting as a cofactor of the enzyme superoxide dismutase and in the regulation of metallothionein synthesis - important proteins of the antioxidant defense system. During physical exercise, zinc compartmentalization may be impaired, that is, changes in the concentration of this mineral occur in cellular compartments. However, the mechanisms involved in the metabolism of zinc, as well as its improvement of physical performance, are not yet fully understood. Thus, further research on the distribution of zinc in organisms subjected to oxidative stress is needed, and also on how zinc deficiency affects the antioxidant capacity during exercise.
Assuntos
Atletas , Estresse Oxidativo , Exercício Físico/fisiologia , Zinco/fisiologia , Zinco/metabolismoRESUMO
OBJETIVO: abordar a importância dos micronutrientes zinco, ferro e vitamina A no crescimento linear e desenvolvimento infantil. MÉTODO: foram consultadas as bases de dados Medline e LILACS utilizando duas estratégias de busca: i) growth AND zinc AND iron AND vitamin A AND child, preschool OR infant, para o tema micronutrientes e crescimento; e ii) child development AND zinc AND iron AND vitamin A, para o tema micronutrientes e desenvolvimento. Os artigos foram classificados quanto ao tipo de manuscrito e principais resultados. RESULTADOS: foram incluídos 19 artigos referentes ao crescimento e 5 artigos referentes ao desenvolvimento. DISCUSSÃO: considerando as prevalências, sugere-se que as deficiências de ferro e zinco devem contribuir, concurrentemente, com o déficit de estatura. O papel do zinco no sistema hormonal primário justifica ser o nutriente de maior importância no crescimento, afetando a estatura das crianças tanto em estados de deficiência leve como moderada. Evidências fisiológicas e experimentais colocam a importância dos micronutrientes ferro e zinco no desenvolvimento e déficit cognitivo nos primeiros anos da vida. Apesar disso, os resultados ainda não são conclusivos. Pensa-se que o zinco pode limitar processos neuropsicológicos específicos, já o ferro é essencial para o funcionamento do sistema neuro-transmissor. Estudar o efeito das deficiências de micronutrientes no desenvolvimento apresenta vários problemas metodológicos e analíticos. O crescimento e desenvolvimento representam um processo com determinação comum no qual a deficiência de zinco pode representar a forma mais comum em que o crescimento linear poderia ser utilizado como um bom preditor de desenvolvimento cognitivo
Assuntos
Saúde da Criança , Cognição , Ferro/fisiologia , Crescimento , Crescimento e Desenvolvimento , Micronutrientes/fisiologia , Vitamina A , Zinco/fisiologiaRESUMO
Zinc is essential for normal brain development. Gestational severe zinc deficiency can lead to overt fetal brain malformations. Although not teratogenic, suboptimal zinc nutrition during gestation can have long-term effects on the offspring's nervous system. This article will review current knowledge on the role of zinc in modulating neurogenesis and neuronal apoptosis as well as the proposed underlying mechanisms. A decrease in neuronal zinc causes cell cycle arrest, which in part involves a deregulation of select signals (ERK1/2, p53, and NF-kappaB). Zinc deficiency also induces apoptotic neuronal death through the intrinsic (mitochondrial) pathway, which can be triggered by the activation of the zinc-regulated enzyme caspase-3, and as a consequence of abnormal regulation of prosurvival signals (ERK1/2 and NF-kappaB). Alterations in the finely tuned processes of neurogenesis, neuronal migration, differentiation, and apoptosis, which involve the developmental shaping of the nervous system, could have a long-term impact on brain health. Zinc deficiency during gestation, even at the marginal levels observed in human populations, could increase the risk for behavioral/neurological disorders in infancy, adolescence, and adulthood.
Assuntos
Neurônios/citologia , Neurônios/metabolismo , Zinco/deficiência , Zinco/fisiologia , Animais , Apoptose/fisiologia , Proliferação de Células , Humanos , Modelos Biológicos , NF-kappa B/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Zinco/metabolismoRESUMO
It is known that zinc modulates nicotinic acetylcholine receptors (nAChRs). Here, we studied the effects of zinc on neuronal alpha4beta4 nAChRs, expressed in Xenopus oocytes and activated by nicotine. Membrane ion currents elicited by nicotine (10 nM to 100 microM) were enhanced by zinc (100 microM). Maximal zinc potentiation of the nicotine-activated current (2530%) occurred at 50 nM nicotine, and potentiation gradually decreased as the nicotine concentration increased. The EC(50) and IC(50) for the nicotine-activated current were 639 nM and 14.7 microM nicotine, respectively. Both parameters decreased in the presence of zinc to 160 nM and 4.6 microM, respectively, probably due to an increase of sensitivity of nAChRs for nicotine. We used different concentrations and durations of exposure to nicotine, due to desensitization of nAChRs directly depends on both these factors. With 500 nM nicotine and 20 min washing periods between nicotine applications, zinc potentiation remained constant, 901% for 2 min and 813% for 20 min of nicotine exposure. With continuous application of nicotine, zinc potentiation decreased as the time of nicotine exposure increased, 721% for 2 min and 254% for 48 min of nicotine exposure. Our results indicate that zinc-potentiating effects on alpha4beta4 nAChRs strongly depend on both concentration and time of exposure to nicotine, suggesting that zinc potentiation depends on the degree of desensitization.