Bone quality and biochemical markers

Osteoporosis is defined as a skeletal disorder characterized by compromised bone strength predisposing a person to an increased risk of fracture. Bone strength primarily reflects the integration of bone density and bone quality. Bone density is expressed as grams of mineral per area or volume, and in any given individual is determined by peak bone mass and amount of bone loss. Bone quality refers to architecture, turnover, damage accumulation (eg, microfractures) and mineralization. However, there are no other methods to evaluate bone quality than biochemical markers at present.     

Bone densitometry and bone biopsy

Bone densitometry is one of the most frequently used investigations in the assessment and management of patients suspected to have osteoporosis. The current method of choice for measuring BMD is dual-energy X-ray absorptiometry, because of its high precision and low radiation dose. The initiation and choice of treatment in patients with osteoporosis is critically dependent on the availability of BMD measurements and BMD can also be used to monitor the response to therapy. Transiliac bone biopsy is indicated for selected patients with metabolic bone disease where less invasive investigations have yielded inconclusive results. Under these circumstances it is an invaluable investigation that can be used to differentiate infiltrative disorders from primary abnormalities of osteoblast or osteoclast function.     

Bone turnover markers in diabetics treated with continuous ambulatory peritoneal dialysis

Low turnover renal osteodystrophy (ROD) is an important problem in patients on CAPD. The aim of the study was to evaluate in CAPD patients the frequency of low turnover ROD with special interest to diabetic nephropathy (DN) as well as estimation the clinical usefulness of some biochemical bone turnover markers in monitoring this complication. The study was performed in group of 54 patients: 28 on CAPD (15 M, 13 F) and 26 on HD (14 M, 12 F). There were 20/28 patients with DN in CAPD group. The observation lasted 12 months. Every 3rd month levels of iPTH, PICP, PINP, ICTP, Ca, P, total AP in serum were determined. Correlation between these biochemical markers of ROD and causes of renal failure, sex, age of patients were analyzed statistically. In CAPD patients significantly lower values of iPTH were found in comparison with HD patients (p < 0.01). In patients with DN levels of iPTH were significantly lower (p < 0.001) than in patients with other causes of renal failure (respectively: iPTH 142 +/- 81 vs 403 +/- 128 pg/ml). In patients with DN treated with CAPD levels of iPTH were significantly lower in men than in women and in younger men with DN (< 50 years). The similar results were found in levels of PINP as a marker of bone formation. Close correlation between PINP and iPTH (r = 0.80) was also found. In summary we showed that low turnover ROD is the predominant bone lesion in CAPD patients. Men with DN < 50 age are specially predisposed to the low turnover ROD. Monitoring of iPTH and PINP levels as sensitive markers of low turnover ROD might be useful in assessment of bone turnover rate in CAPD patients.     

Bone metabolism markers and bone mass in healthy pubertal boys and girls

OBJECTIVE: During puberty, bone growth and mineralization as well as bone turnover increase dramatically. The relation between height velocity and bone turnover is already known, but there are few studies in which both bone metabolism markers and bone mass throughout puberty have been measured. DESIGN: Semi-longitudinal study. In 155 healthy boys (12.0 +/- 1.5 years; range 8.8-15.7 years) and 151 healthy girls (11.2 +/- 1.6 years; range 8.2-14.0 years) markers of bone formation and bone resorption were measured as well as sex steroids, IGF-1 and IGF-BP3, together with bone mineral content (BMC) and bone mineral density (BMD) of the lumbar spine, femur and total body during puberty. All bone measurements were repeated after 1 year. RESULTS: BMC and BMD increased throughout puberty in both sexes. Bone turnover markers increased significantly until maximum values were reached at stage G4 in boys and stage B3 in girls. Height velocity (HV) had a similar changing pattern. Sex steroids and IGF-1 increased and reached adult values at pubertal stage 4. The correlations between bone metabolism markers and BMC were highly significant in boys, while correlations between bone metabolism markers and the increase in BMC over 1 year were significant in both sexes, as was observed for the correlations with HV. CONCLUSIONS: Our data suggest that bone metabolism markers are good predictors of bone mass in boys and of bone mass increase in both sexes. In early puberty, sex steroids stimulate the pubertal growth spurt in conjunction with GH and IGF-1. The fast increase in height gives rise to an increase in bone turnover and bone mineral apposition. It is known that at the end of puberty high levels of oestradiol inhibit chondrocyte proliferation. This leads to a decline in height velocity and bone turnover. Bone mass still increases under the influence of sex steroids and IGF-1. The data in our study confirm previous reports that markers of bone turnover relate positively to height velocity.     

Bone metabolic markers and diagnosis of abnormal bone and calcium metabolism

Bone metabolic markers increase in blood or urine, when bone formation or bone resorption accelerates. Reference values of bone metabolic markers are determined in male or female, and in pre- or post-menopause, respectively. Values of bone metabolic markers in most patients with primary osteoporosis were distributed within a reference value, mean+/-1.96 SD. When measured values exceeded a reference values, we should survey a possibility of abnormal calcium or bone metabolism such as primary hyperparathyroidism, renal osteodystrophy, hyperthyroidism and Paget's disease of bone or bone metastasis associated with malignant tumor.     

Bone densitometry in patients with multiple myeloma.

PURPOSE, PATIENTS, AND METHODS: We performed dual-energy x-ray absorptiometry in 10 selected patients with aggressive multiple myeloma in whom substantial tumor mass reduction was achieved after high-dose chemoradiotherapy followed by autologous blood stem cell transplantation. RESULTS: In most cases, bone mineral density (BMD) of the spine was initially low (Mean Z score: -2.69, SEM 0.76) and dramatically increased after treatment (mean increase 16.4%; 7.7% with 95% confidence interval 2.2 to 12.2, excluding one patient whose spine BMD increased by 94.8%). In contrast, skeletal roentgenograms, computed tomographic scans, and magnetic resonance imaging did not reveal any significant improvement of patients' bone lesions. CONCLUSIONS: In patients with multiple myeloma, bone densitometry could be a useful way to assess the efficacy of treatment on bone status.     

甲状腺机能亢进症患者部分骨代谢生化指标的变化及分析

目的　查明甲状腺机能亢进症患者血清骨钙素 (BGP)、碱性磷酸酶 (AL P)及尿羟脯氨酸 (HOP) ,观察其变化并进行分析。方法　以 30例甲亢患者及 15例正常人为研究对象 ,测定 BGP、AL P、尿 HOP等指标。结果　甲亢患者血清 BGP(11.18± 4.74) ng/ m l和尿 HOP(2 4.32± 11.2 1) mg/ g.Cr均高于正常对照组 (P <0 .0 5)。结论　骨吸收增加和骨形成相对降低可能为甲亢患者骨代谢异常发生的主要原因     

Biochemical markers and bone densitometry in inflammatory bowel disease.

AIMS: Bone mineral density is reduced in patients with inflammatory bowel disease. The possible causes of this situation are delayed puberty, malabsorption, and corticosteroid use, among others. No published data exist regarding the use of biochemical markers and bone densitometry to assess osteopenia in these patients in Spain. METHODS: We studied 54 patients (24 men and 30 women), 22 with Crohn's disease and 32 with ulcerative colitis. Age, type of disease and average daily dose of prednisone-equivalent corticosteroids were evaluated. Lumbar bone mineral density was assessed quantitative digital radiography densitometry. The bone resorption marker urine D-pyridinoline and the bone formation marker serum osteocalcin were also assessed. RESULTS: Mean age was 36.61 +/- 13.37 years. Daily corticosteroid dose was correlated with D-pyridinoline (r = 0.413; p < 0.01), and D-pyridinoline was inversely correlated with osteocalcin (r = -0.304; p < 0.01). There was a negative correlation between bone mineral density and corticosteroid dose. There was no relationship between biochemical markers and bone densitometry findings in these patients. There were no differences in terms of bone densitometry findings or biochemical markers between the two types of inflammatory bowel disease. CONCLUSIONS: D-pyridinoline correlated inversely with osteocalcin. Daily corticosteroid dose correlated directly with D-pyridinoline, and inversely with bone mineral density.     

老年女性2型糖尿病患者骨代谢标志物变化研究

目的 探讨老年女性2型糖尿病患者骨代谢标志物的特征. 方法 对我院内分泌科住院44例老年女性2型糖尿病患者(均为绝经后)的骨代谢标志物进行检测.糖尿病患者根据病程分为耱尿病1组(糖尿病病程＜10年)及糖尿病2组(糖尿病病程≥10年);根据糖化血红蛋白水平(HbA1c)分为糖尿病3组(HbA1c＜8％)及糖尿病4组( HbA1c≥8％),目前临床上建议老年患者HbA1c水平控制在＜8％为宜.同时选取我院50例体检健康女性作为对照组.结果 (1)耱尿病组25-羟维生素D3、Ⅰ型前胶原氨基末端(C端)前肽(PICP)明显低于正常对照组,而抗酒石酸碱性磷酸酶(TrACP-5b)较对照组明显升高,且有统计学差异(P＜0.05).(2)糖尿病2组患者血Ⅰ型前胶原氨基末端(N端)前肽(PINP)和PICP水平明显低于糖尿病1组患者(P＜0.05),而TrACP-5b水平高于1组,雌二醇、25-羟维生素D3则无明显统计学差异.(3)糖尿病3组血PINP、PICP明显高于糖尿病4组,TrACP-5b低于4组,差异存在统计学意义(P＜0.05).(4) HbA1c与HNP、PICP和TrACP-5b存在显著相关性,而雌二醇与PINP、PICP、25-羟维生素D3、TrACP-5b无明显相关性. 结论 2型糖尿病患者的骨形成降低,而骨吸收增加.这提示糖尿病患者的骨质形成减弱、骨质破坏增加.随着糖尿病病程的延长,患者的骨质形成速率减慢,骨吸收增加.血糖控制不佳会对骨的形成及骨质的吸收产生影响,因而严格的血糖控制可有效延缓骨质疏松进展.     

Bone densitometry: technical principles and practical value]

X-ray dual photon absorptiometry has replaced isotopic mono and dual photon absorptiometry in the assessment of metabolic bone diseases. This method is a valuable tool for epidemiologic studies. Individual examinations give poor in vivo accuracy and precision. Further technical improvements are needed to give bone densitometry a predictive value for osteoporotic risk.     

男性糖尿病患者部分骨代谢生化指标的测定

对４２例男性糖尿病患者测定了血清２５羟维生素Ｄ３（２５ＯＨＤ３）和完整骨钙素（ＩＢＧＰ）、尿羟脯氨酸（ＨＯＰ）和Ｉ型胶原交联Ｃ末端肽。结果：①Ⅱ型糖尿病患者的血清２５ＯＨＤ３水平低于正常对照组（Ｐ〈０．０５），而Ｉ型糖尿病患者与对照组比较无显著性差异。②糖尿病患者的ＩＢＧＰ均低于对照组，并有显著性差异（Ｐ〈０．０１）。③糖尿病患者的尿ＨＯＰ和Ｃｒｏｓｓｌａｐｓ均高于对照组，有显著性差异（Ｐ分别〈０     

骨代谢生化标志物在氟骨症研究中的应用

氟骨症骨转换加速，骨代谢异常。用成骨细胞分泌的酶如骨碱性磷酸酶、骨钙素等骨代谢生化标志物评估骨形成，用破骨细胞分泌的酶如抗酒石酸酸性磷酸酶及骨吸收中形成的代谢产物如尿羟脯氨酸等生化标志物评估骨吸收。目的是为氟骨症的研究提供新的参考。     

淫羊藿黄酮对被动吸烟大鼠骨量与骨代谢生化指标的影响及其相关性研究

目的探讨淫羊藿黄酮干预对被动吸烟大鼠骨量与骨代谢生化指标的影响及其相关性。方法选用2月龄Sprague-Dawley(SD)大鼠60只,随机分为6组,每组10只,各组雌雄各半,雌雄分笼饲养。A组:空白对照组,常规方法饲养,不给予被动吸烟;B组:被动吸烟组,不给予灌服药物;C组:被动吸烟+钙组,灌服高效钙(75 mg·kg~(-1)·d~(-1))+维生素D_321 IU·kg~(-1)·d~(-1);D组:被动吸烟+低剂量[灌服淫羊藿黄酮(75mg·kg~(-1)·d~(-1))];E组:被动吸烟+中剂量[灌服淫羊藿黄酮(150 mg·kg~(-1)·d~(-1))];F组:被动吸烟+高剂量[灌服淫羊藿黄酮(300 mg·kg~(-1)·d~(-1))]。按"密室熏烟法"给予实验的(B、C、D、E、F组)大鼠被动吸烟4个月。实验动物干预8周和4个月时测定血Ca、血P、血ALP、尿Ca、尿P、血清骨钙素、抗酒石酸酸性磷酸酶、尿脱氧吡啶啉、股骨和腰椎骨密度,并分析骨密度与骨代谢生化指标之间的相关性。结果 (1)股骨和腰椎骨密度、BGP在第8周和在4个月末时血ALP指标A、C、D、E、F组较B组为高,其差异有统计学意义(P0.05);D、E、F组随淫羊藿黄酮剂量的增加而增加,但其相互之间差异无统计学意义(P0.05);其它各组之间相互比较其差异无统计学意义(P0.05)。TRACP的活性、Dpd浓度、在第8周和在4个月末时尿Ca、尿Hop指标A、C、D、E、F组较B组为低,其差异有统计学意义(P0.05);D、E、F组随淫羊藿黄酮剂量的增加而降低,但其相互之间差异无统计学意义(P0.05);其它各组之间相互比较其差异无统计学意义(P0.05)。(2)在第8周及在4个月末时尿Ca、尿Hop和TRACP及Dpd/Cr指标A、C、D、E、F组较B组为低,其差异有统计学意义(P0.05);D、E、F组随淫羊藿黄酮剂量的增加而降低,但其相互之间差异无统计学意义(P0.05);其它各组之间相互比较其差异无统计学意义(P0.05)。股骨和腰椎骨密度与BGP、ALP呈明显正相关(r=0.784及0.816,P0.05;r=0.743及0.807,P0.05)。股骨和腰椎骨密度与TRACP的活性、Dpd浓度、尿Ca、尿Hop呈明显负相关(r分别=-0.617、-0.608、-0.587、-0.611,P0.05;r分别=-0.614、-0.621、-0.583、-0.617,P0.05)。结论淫羊藿黄酮干预可明显改善被动吸烟大鼠的骨密度和骨生化指标,且骨密度与骨生化指标之间存在明显的相关性。