RESUMO
Reduced serum magnesium concentrations in women with breast cancer compromises one of the antioxidant defense system involved in the carcinogenesis process. To evaluate parameters of magnesium, the enzyme activity of superoxide dismutase, and its relation with oxidative stress markers in women with breast cancer. A case-control study was conducted, involving 60 women in the age range between 29 and 65 years, divided into two groups: women with breast cancer (n = 30) and women without breast cancer (n = 30). Plasma; ionized, erythrocytic, and urinary magnesium intake; plasma concentrations of thiobarbituric acid reactive substances; and erythrocyte superoxide dismutase enzyme activity were evaluated. The mean value of the amount of dietary magnesium was below the recommended level in both groups studied, with no statistical difference (p > 0.05). Plasma, ionized, and erythrocyte magnesium concentrations of women with breast cancer were reduced in relation to the control group (p < 0.0001) and inadequate according to the reference values. Urinary excretion was high, with a significant difference between groups (p < 0.0001). The mean concentration of thiobarbituric acid reactive substances was high in the study participants, with no significant statistical difference between the groups (p > 0.05). The mean values of superoxide dismutase enzyme activity were adequate, with no statistically significant difference between the groups (p > 0.05). Women with breast cancer have impaired magnesium homeostasis, characterized by its reduction in diet, plasma, and erythrocytes and its increase in urine.
Assuntos
Neoplasias da Mama , Magnésio , Adulto , Idoso , Estudos de Casos e Controles , Eritrócitos/metabolismo , Feminino , Humanos , Pessoa de Meia-Idade , Estresse Oxidativo , Superóxido Dismutase/metabolismo , Substâncias Reativas com Ácido TiobarbitúricoRESUMO
Breast cancer is a disease of high mortality, characterized by the progressive accumulation of mutations that contribute to the uncontrolled development of breast tissue cells. Literature shows that disturbances in mineral homeostasis, such as magnesium, may interfere with tumor progression. The objective of this study is to provide updated information about magnesium's role in the pathogenesis of breast cancer. A review of literature was carried out from a search for articles in the PubMed and CAPES Periodicals databases published between 1995 and 2016 with the cross-references of the descriptors "magnesium," "breast neoplasms," and "oxidative stress" and the corresponding words in Portuguese. We included studies on the metabolism and bioavailability of magnesium and studies related to breast cancer and excluded articles in which only the abstract was available, dissertations, theses, articles involving adjuvant and/or neoadjuvant therapies, and supplementation of minerals in breast cancer patients. Magnesium is a mineral that participates in the metabolism of various nutrients and nucleic acids. In the presence of breast cancer, neoplastic cells increase the expression of magnesium transport channels, which raises the intracellular concentration of the mineral, contributing to tumor growth through its function of increasing energy demand. The data obtained in this review illustrates the influence of magnesium on the progression of breast cancer. However, the existing data are scarce and inconsistent, which demonstrates a need for further studies on the subject with a goal to have better control of the disease.
Assuntos
Neoplasias da Mama/metabolismo , Homeostase , Magnésio/metabolismo , Estado Nutricional , Disponibilidade Biológica , Neoplasias da Mama/patologia , Suplementos Nutricionais , Progressão da Doença , Humanos , Magnésio/administração & dosagem , Magnésio/farmacocinéticaRESUMO
OBJECTIVE: This study assessed the relationship between the parameters of glycemic control, and zinc concentrations in blood and superoxide dismutase enzyme activity in type 2 diabetes patients. SUBJECTS AND METHODS: Seventy-three individuals, aged between 25 and 59 years, were divided into the experimental group (type 2 diabetes patients, n = 36) and control group (n = 37). Plasma and erythrocyte zinc concentrations, superoxide dismutase activity, and parameters of glycemic control were analyzed. RESULTS: Mean plasma zinc concentration was 74.1 ± 10.7 µg/dL and 68.8 ± 9.6 µg/dL, erythrocyte zinc concentration was 48.1 ± 9.5 µg/gHb and 41.2 ± 8.0 µg/gHb, and superoxide dismutase activity was 2248.9 ± 300.0 U/gHb and 2059.6 ± 285.4 U/gHb, in the experimental group and the control group, respectively (p < 0.05). CONCLUSION: Type 2 diabetes patients showed a positive response to oxidative stress due to adequate zinc concentration in blood and increased activity of superoxide dismutase, and the enzyme was influenced by serum insulin.
Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Insulina/sangue , Superóxido Dismutase/metabolismo , Zinco/sangue , Adulto , Estudos de Casos e Controles , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/enzimologia , Eritrócitos/enzimologia , Feminino , Humanos , Lipídeos/sangue , Masculino , Pessoa de Meia-Idade , Estado Nutricional , Superóxido Dismutase/sangueRESUMO
OBJECTIVE: This study assessed the relationship between the parameters of glycemic control, and zinc concentrations in blood and superoxide dismutase enzyme activity in type 2 diabetes patients. SUBJECTS AND METHODS: Seventy-three individuals, aged between 25 and 59 years, were divided into the experimental group (type 2 diabetes patients, n = 36) and control group (n = 37). Plasma and erythrocyte zinc concentrations, superoxide dismutase activity, and parameters of glycemic control were analyzed. RESULTS: Mean plasma zinc concentration was 74.1 ± 10.7 µg/dL and 68.8 ± 9.6 µg/dL, erythrocyte zinc concentration was 48.1 ± 9.5 µg/gHb and 41.2 ± 8.0 µg/gHb, and superoxide dismutase activity was 2248.9 ± 300.0 U/gHb and 2059.6 ± 285.4 U/gHb, in the experimental group and the control group, respectively (p < 0.05). CONCLUSION: Type 2 diabetes patients showed a positive response to oxidative stress due to adequate zinc concentration in blood and increased activity of superoxide dismutase, and the enzyme was influenced by serum insulin.
OBJETIVO: O estudo investigou a relação entre parâmetros do controle glicêmico, a zincemia e a atividade da enzima superóxido dismutase em pacientes diabéticos tipo 2. SUJEITOS E MÉTODOS: Setenta e três indivíduos, de 25 a 59 anos de idade, foram distribuídos em grupo caso (diabéticos tipo 2, n = 36) e grupo controle (n = 37). Foram analisados zinco plasmático e eritrocitário, atividade da enzima superóxido dismutase e parâmetros do controle glicêmico. RESULTADOS: A média de zinco plasmático foi 74,1 ± 10,7 µg/dL e 68,8 ± 9,6 µg/dL; de zinco eritrocitário foi 48,1 ± 9,5 µg/gHb e 41.2 ± 8.0 µg/gHb; e da atividade da superóxido dismutase foi 2248,9 ± 300,0 U/gHb e 2059,6 ± 285,4 U/gHb no grupo caso e grupo controle, respectivamente (p < 0,05). CONCLUSÃO: Os pacientes diabéticos tipo 2 mostram uma resposta positiva ao estresse oxidativo devido à zincemia adequada e ao aumento da atividade da superóxido dismutase, sendo essa enzima influenciada pela insulina sérica.