[Erythrocytic acid phosphatase genetic polymorphism and cardiovascular risk in health children and adolescents]. / Polimorfismo genético da Fosfatase Acida do eritrócito e risco cardiovascular em crianças e adolescentes saudáveis.

OBJECTIVE: To correlate, in a sample of healthy children and adolescents, the activity of the enzyme acid phosphatase (ACP) with its different genetic phenotypes and of these with some cardiovascular risk parameters such as body mass index (BMI), percentage of total fat mass (%TFM), trunk fat (TF), insulin resistance, and the arterial blood pressure (BP). DESIGN AND METHODS: The sample was composed of 173 healthy children and adolescents, 96 (55.5%) F and 77 (44.5%) M, with ages between 10 and 16 years (mean: 13.04 +/- 1.68). The ACP activity was determined through a spectrophotometric method and its phenotypes through isoelectric focusing electrophoresis. BMI (Kg/m2) and the BP were obtained by standardized methods. Glycemia determined by the glucose oxidase method and insulinemia by RIA method. Insulin resistance based on the homeostasis model assessment (HOMA) was calculated as: [fasting insulin (microU/ml) x fasting glucose (mmol/l)]: 22.5. The %TFM and TF were determined by dual energy x-ray absorptiometry (DXA). The statistical methods used were ANOVA, the Pearson correlation and the Student's test. RESULTS: The distribution of the phenotypes were the following--absolute versus relative frequencies: BB-74 (48.4%), AB-52 (34%), AA-16 (10.5%), BC-7 (4.6%), AC-3 (2%) and CC-1 (0.7%). ACP activities (mean: 321.04 +/- 84.56) were significantly different among the phenotypes (p < 0.001). The smallest activity was observed in the AA individuals, the highest in CC, followed by BC (247.17 +/- 66.52 and 767.30 and 362.44 +/- 91.56 respectively). Glycemia was higher in the AA individuals (4.61 +/- 0.37) compared to CC + BC (4.40 +/- 0.31) (p = 0.08). A direct correlation was verified between HOMA and BP, both diastolic (p = 0.013, r = 0.250) and systolic (p = 0.015, r = 0.246), as well as of these with BMI (mean: 20.57 +/- 3.24) and insulinemia (p = 0.016, r = 0.215; p = 0.004, r = 0.280 and p = 0.007, r = 0.240; p = 0.008, r = 0.261 respectively for diastolic and systolic BP). There were no significant difference of BMI between sexes, nor of this as well as of % TFM and TF among the different genetic phenotypes of ACP. CONCLUSIONS: The smallest enzymatic activity of ACP seems to be associated with the AA individuals, where a trend for higher glycemia was verified. BMI, HOMA and insulinemia, due to their significant direct relationship with diastolic and systolic BP in this sample of children and adolescents may warrant more future attention in the evaluation of cardiovascular risk. There were no significant differences of HOMA, BMI, %TFM, TF nor of BP among the different ACP genetic phenotypes.

[Ionized calcium and magnesium as interdependent variables in blood pressure origin in healthy adolescents]. / Cálcio e magnésio ionizados como variáveis interdependentes na génese da pressão arterial, em adolescentes saudáveis.

INTRODUCTION: Growing evidence indicates that diet divalent cations--ionized calcium (Ca) and magnesium (Mg)--and MN blood group polymorphism may be associated with essential arterial hypertension. OBJECTIVES: To assess a possible relationship between serum ionized Ca and Mg and MN blood group polymorphism with blood pressure (BP) and body mass index (BMI). POPULATION AND METHODS: The study group consisted of 173 healthy adolescents, 96 female (55.5%) and 77 male (44.5%), with mean age of 13.0 +/- 1.7 years. Serum ionized Ca and Mg were determined by standardized methods based on detection by specific electrodes. MN blood group polymorphism was determined by immunoaglutination of erythrocytes with monoclonal antibodies. BP was evaluated based on AHA recommendations. BMI was calculated as weight divided by squared height (Kg/m2). The statistical method used was the Pearson correlation. RESULTS: In this population no significant correlation was found from serum ionized Ca (mean: 1.07 +/- 0.06 mmol/L) and Mg (mean: 1.15 +/- 0.97 mmol/L) with systolic BP (mean: 113.1 +/- 10.7 mmHg) and diastolic BP (mean: 66.1 +/- 10.1 mmHg). In contrast there was an inverse correlation between the quotient ionized Mg/ionized Ca (0.45 +/- 0.05) and diastolic BP (p = 0.029; r = -0.381). A positive correlation was found between BMI (20.57 +/- 3.24 Kg/m2) and systolic BP (p = 0.007; r = 0.24) and diastolic BP (p = 0.016; r = 0.22). No correlation was found between ionized Ca, ionized Mg and BP with MN blood group polymorphism. CONCLUSIONS: In this population of healthy adolescents there was a dependence between diastolic BP and serum ionized Mg/ionized Ca. There was no interindividual BP and ionized Ca and Mg variation dependent from genetic variation.