Impacto da maturação esquelética em biomarcadores do metabolismo ósseo e na densidade mineral óssea em adolescentes brasileiros saudáveis / Impact of skeletal maturation on bone metabolism biomarkers and bone mineral density in healthy Brazilian male adolescents

OBJETIVO: Avaliar o comportamento de biomarcadores de formação e reabsorção óssea em adolescentes brasileiros em função da sua maturação biológica. MÉTODOS: Oitenta e sete voluntários foram divididos em grupos segundo a idade óssea (IO): 10-12 anos (n = 25), 13-15 anos (n = 36) e 16-18 anos (n = 26). Foram analisados peso (kg), estatura (m), índice de massa corporal (kg/m2), ingestão de cálcio de 3 dias (mg/dia), avaliação dos eventos pubertários pelos critérios de Tanner, níveis dos biomarcadores [osteocalcina (OC) (ng/mL), fosfatase alcalina óssea (FAO) (U/L), telopeptídeo carboxiterminal sérico (S-CTx) (ng/mL)] e sua correlação com a densidade mineral óssea (DMO) (g/cm2) por atenuação de raios X de dupla energia da coluna lombar, do fêmur proximal e de corpo total. RESULTADOS: Os biomarcadores mostraram comportamento semelhante, apresentando medianas elevadas dos 13 aos 15 anos (FAO = 154,71 U/L, OC = 43,0 ng/mL, S-CTx = 2,09 ng/mL; p < 0,01) e no estágio puberal G4. As medianas decresceram com o avançar da IO e da maturação sexual. Os níveis dos biomarcadores mostraram paralelismo com pico de velocidade em estatura, e, curiosamente, os biomarcadores de formação indicaram correlação negativa com a DMO, isto é, valores de DMO elevados se correlacionaram com valores baixos dos biomarcadores. CONCLUSÕES: Este é o primeiro estudo em adolescentes brasileiros com critérios de inclusão e exclusão rígidos e cuidadosos a avaliar a correlação entre marcadores ósseos e DMO frente a indicadores da maturação biológica. Os resultados ajudam a compreender o turnover ósseo e o monitoramento do metabolismo ósseo.

OBJECTIVE: To evaluate the behavior of biomarkers of bone formation and resorption in healthy male Brazilian adolescents according to their biological maturation. METHODS: Eighty-seven volunteers were divided into age groups according to bone age (BA): 10-12 years (n = 25), 13-15 years (n = 36), and 16-18 years (n = 26). Weight (kg), height (m), body mass index (kg/m2), calcium intake from 3 days assessed by 24-h food recall (mg/day), pubertal event evaluation by Tanner criteria, and serum biomarker levels (osteocalcin [OC] [ng/mL], bone alkaline phosphatase [BAP] [U/L], and serum carboxyterminal telopeptide [S-CTx] [ng/mL]) were recorded and correlated to bone mineral density (BMD) (g/cm2) measured by dual energy X-ray absorptiometry of the lumbar spine, proximal femur, and whole body. RESULTS: Biomarkers showed similar behaviors, presenting higher median values in the 13-15 year group (BAP = 154.71 U/L, OC = 43.0 ng/mL, S-CTx = 2.09 ng/mL; p < 0.01) and when adolescents were in the pubertal stage G4. Median biomarker values decreased with advancing BA and sexual maturation. Biomarker values showed parallelism with peak height velocity, and, interestingly, bone formation biomarkers indicated significant negative correlation with BMD in the different evaluated locations, i.e., higher BMD values correlated with lower bone biomarker values. CONCLUSIONS: This is the first study of healthy Brazilian adolescents with rigid and careful inclusion and exclusion criteria to assess the correlation of bone markers and BMD with biological maturation indicators. Our results can help understand bone turnover and monitor bone metabolism.

Genotypes of vitamin D and estrogen receptors in pre and perimenopausal women from Córdoba, Argentina

El propósito del estudio fue determinar la frecuencia de los genotipos de los receptores de vitamina D y de estrógeno y su relación con la densidad mineral ósea en mujeres sanas pre y perimenopáusicas de la ciudad de Córdoba y alrededores. Los genotipos se determinaron con la técnica de reacción en cadena de la polimerasa y análisis de los polimorfismos de longitud de fragmentos de restricción. Se usaron como restrictasas Bsm I y Fok I para el gen del receptor de vitamina D y Pvu II y Xba I para el gen del receptor de estrógeno. Se reclutaron y agruparon por edad doscientos diez mujeres pre y peri-menopáusicas. Sus niveles séricos de Ca y de hormona paratiroidea fueron similares, pero los de fósforo y b-Cross Laps disminuyeron con la edad. La densidad mineral ósea de cuello femoral disminuyó después de los 30 años. Las frecuencias genotípicas de ambos receptores fueron similares a aquéllas de otras mujeres caucásicas. No hubo asociación entre los genotipos de los receptores y la densidad mineral ósea. Los análisis de interacción entre ambos genes no evidenciaron influencia sobre la densidad mineral ósea, utilizándose edad, talla e índice de masa corporal como covariables. Los estilos de vida y hábitos de fumar y beber alcohol tampoco afectaron la densidad mineral ósea. En conclusión, estos datos no sostienen la hipótesis de que los genotipos de los receptores de vitamina D y de estrógeno influencian la densidad mineral ósea de columna lumbar y cuello femoral en mujeres sanas pre y perimenopáusicas de esta región de Argentina.

The aim of this study was to determine the frequency of vitamin D receptor and estrogen receptor genotypes and their relationship with the lumbar spine or femoral neck bone mineral density in healthy pre and perimenopausal women from Córdoba (Argentina) and adjacent areas. Genotypes were assessed by restriction fragment length polymorphism-polymerase chain reaction technique. Bsm I and Fok I for vitamin D receptor gene and XbaI and PvuII for estrogen receptor gene were used as restrictases. Two hundred and ten healthy pre and perimenopausal women were recruited and analyzed by age. Calcemia and serum parathyroid hormone did not change, but serum P and b-CrossLaps decreased with age. Femoral neck bone mineral density decreased significantly after 30 years old. Vitamin D receptor and estrogen receptor genotype frequencies were similar to those from other Caucasian women. No association between vitamin D receptor and estrogen receptor genotypes with the lumbar spine or femoral neck bone mineral density has been detected. Analysis of interaction between vitamin D receptor and estrogen receptor genes using covariates such as age, height and body mass index did not show any influence of the combination of those genotypes on bone mineral density. Lifestyle, smoking and alcohol intake had no effect on lumbar spine and femoral neck bone mineral density. To conclude, these data do not support the hypothesis that vitamin D receptor and estrogen receptor genotypes influence on lumbar spine and femoral neck bone mineral density in healthy pre and perimenopausal women from this area of Argentina.

Clinical application of biochemical markers of bone turnover / Marcadores bioquímicos da remodelação óssea

With the ageing population in most countries, disorders of bone and mineral metabolism are becoming increasingly relevant to every day clinical practice. Consequently, the interest in, and the need for effective measures to be used in the screening, diagnosis and follow-up of such pathologies have markedly grown. Together with clinical and imaging techniques, biochemical tests play an important role in the assessment and differential diagnosis of metabolic bone disease. In recent years, the isolation and characterisation of cellular and extracellular components of the skeletal matrix have resulted in the development of molecular markers that are considered to reflect either bone formation or bone resorption. These biochemical indices are non-invasive, comparatively inexpensive and, when applied and interpreted correctly, helpful tools in the diagnostic and therapeutic assessment of metabolic bone disease. This review provides an overview of the current evidence regarding the clinical use of biochemical markers of bone remodelling in bone disease, with an emphasis on osteoporosis.

Tendo em vista o crescimento da população idosa na maioria dos países, os distúrbios do metabolismo ósseo e mineral estão tornando-se cada vez mais relevantes na prática clínica diária. Conseqüentemente, o interesse e a necessidade de medidas efetivas para serem usadas no rastreamento, diagnóstico e seguimento de tais patologias vêm crescendo acentuadamente. Além da avaliação clínica e de técnicas de imagens, os marcadores bioquímicos desempenham um importante papel na avaliação e diagnóstico das doenças ósseas metabólicas. Recentemente, a melhor caracterização dos componentes intracelulares e extracelulares da matriz óssea resultou no desenvolvimento dos marcadores moleculares, os quais refletem tanto a formação como a reabsorção óssea. Estes marcadores bioquímicos não são invasivos e comparativamente são de mais baixo custo, e quando aplicados e interpretados corretamente são instrumentos úteis no diagnóstico e tratamento das doenças ósseas metabólicas. Esta revisão abordará evidências atuais, levando em consideração o uso clínico dos marcadores bioquímicos da remodelação óssea nas doenças metabólicas ósseas, com ênfase na osteoporose.

Study of procollagen type1 nitrogenous propeptides (P1NP) in reproductive female.

A study of 109 female volunteers in good health and reproductive life, the mean age was 38.5 years, the volunteers had no intake of any kind of medicine before blood examination. The mean value of PINP is 44.57 ng/ml, standard deviation= 19.91, standard error= 1.9 with 95% confident interval = 40.79 to 48.35 ng/ml The PINP is a bone formation marker which is secreted by osteoblast, the advantage of the present study was helping the evaluation of bone status after bone forming agents therapy. In addition PINP showed the status of bone turnover when compared to bone resorption marker (CTx).