骨代谢疾病的实验室检查 详解.ppt

血浆抗酒石酸酸性磷酸酶TRACP 破骨细胞富含TRACP，骨吸收增加的疾病可呈中度升高，但TRACP很稳定。在病理状态下改变范围也小，其判断骨吸收的价值不如吡啶啉一类 常用酶动力学法、电泳法检测。目前已有酶标法应用于临床。 尿吡啶啉和脱氧吡啶啉PYD和DO-PYD 是目前很有价值的骨吸收指标。 是胶原纤维之间的连接物，使胶原纤维共价交联稳定相聚合。 PYD存在于骨、软骨、牙齿、肌键等结缔组织中，而D-PYD仅存在于骨与牙的I型胶原中，后者量微，故D-PYD主要来自骨骼。 激素辅助风险评估 雌激素 提高成骨细胞的活性。 低水平： 10 pg/ml ? 骨质流失轻度增加, 5 pg/ml ? 流失严重 男性： 13 pg/ml ? 骨折风险亦增加 睾酮 男性性功能减退 (游离睾酮 9 pg/ml) 与轻度臀部骨折相关。 性激素结合球蛋白(SHBG) 血液中的运输性激素的蛋白质 高浓度的SHBG 可降低游离激素的生物活性 增加男性和绝经后女性的骨折风险 SHBG与BMD呈负相关。 骨代谢标志物临床应用 临床意义 监测骨丢失速率 预测骨折风险 监测疗效 用以调整治疗方案 代谢性骨病鉴别 监测老化速率 如何使用 骨吸收标志物 每6个月一次 药物治疗时 治疗前 治疗开始后3或6个月 骨形成标志物 治疗开始前 治疗开始后6个月 * 分布：99% 贮存于骨组织 1% 贮存于体液及其他组织 * Endocrine control of calcium homeostasis.Parathyroid hormone (PTH) is secreted from the parathyroid glands (four circles). A new auxiliary source of PTH has been located in the thymus. PTH increases mobilization of calcium (Ca) from bone by enhancing bone turnover. In the kidney, PTH stimulates tubular reabsorption of Ca and favors the synthesis of the steroid vitamin D hormone, calcitriol. The main physiological function of calcitriol is to increase intestinal Ca absorption. Therefore, all effects of PTH act to directly or indirectly increase the calcium concentration in the extracellular fluids. An increase in the concentration of ionized Ca in the extracellular fluids is the major feedback mechanism that inhibits PTH secretion from the parathyroid glands and possibly also from the thymus by a Ca-sensing receptor expressed in the membrane of PTH-secreting cells. In the absence of parathyroid glands, thymic PTH secretion seems to be a backup mechanism for emergency regulation of Ca metabolism. * Calcitonin is produced by parafollicular cells that surround the thyroid follicular cells. These parafollicular cells, or C cells, are derived from the neural crest and migrate into the thyroid gland. In submammalian species, CT is produced by a discrete ultimobranchial body. CT is a small peptide of 32 amino acids, has a molecular weight of 3500, and is uni