Decreased bone formation and increased mineral dissolution during acute fasting in young women.
Decreased bone formation and increased mineral dissolution during acute fasting in young women.
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DOI：
10.1210/jcem.80.12.8530611
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发表时间：
1995-12
期刊：
影响因子：
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通讯作者：
S. Grinspoon;H. Baum;V. Kim;C. Coggins;A. Klibanski
中科院分区：
文献类型：
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作者：
S. Grinspoon;H. Baum;V. Kim;C. Coggins;A. Klibanski
严重的慢性营养不良与骨转换降低和显著的骨丢失有关。然而，营养缺乏对骨转换的短期影响知之甚少。为了研究短期禁食对骨代谢的影响以及酸中毒对这些变化的贡献，14名年龄为18-26岁（平均21 +/- 2（SD年））的健康女性在完整的4天禁食期间随机接受碳酸氢钾（KHCO 3，2 meq/kg/天，分次剂量）预防酸中毒或对照（氯化钾，25 meq/天）。使用特定的骨形成标志物[骨钙素（OC）和I型前胶原羧基末端前肽（PICP）]和骨吸收标志物[吡啶啉（PYRX）和脱氧吡啶啉（DPYRX）]评估骨转换。对照组的血清碳酸氢盐水平从27.0 +/- 3.2 mmol/L显著下降至17.3 +/- 2.6 mmol/L（P < 0.01），与接受KHCO 3的患者相比有所下降[17.3 +/- 2.6 vs 23.4 +/- 2.4 mmol/L，（P < 0.001）]。对照组血清总钙和离子钙显著升高[分别为9.1 +/- 0.1至9.4 +/- 0.2 mg/dL（P < 0.01）和1.20 +/- 0.03至1.23 +/- 0.03 mmol/L（P < 0.05）]，但接受KHCO 3治疗的患者则没有。此外，对照组的血清甲状旁腺激素（PTH）水平从32 +/- 17降至16 +/- 10 pg/mL（P < 0.05），尿钙排泄量增加[86 +/- 51至182 +/- 103 mg/天（P = 0.01）]，但接受KHCO 3的患者则没有。禁食4天后，血清骨钙素（OC）和前胶原羧基末端前肽（PICP）水平从9.1 +/- 3.4 ng/mL显著降低至5.5 +/- 4.2 ng/mL（P < 0.01）和121 +/- 21至46 +/- 13 ng/mL（P = 0.0001）分别在接受碳酸氢盐的患者中，对照组分别为10.1 ± 3.3 ~ 4.0 ± 2.9 ng/mL（P < 0.01）和133 ± 22 ~ 47 ± 19 ng/mL（P < 0.001）。两个治疗组空腹期间骨钙素和PICP的降低相当。相比之下，尿液排泄PYRX和DPYRX没有显着变化，在任何一组禁食4天。这些数据首次证明骨形成标志物在短期禁食下显著下降，与酸碱状态的变化无关。相比之下，这些数据表明，酸中毒刺激钙释放从骨在短期禁食的直接影响，并表明，酸中毒可能会增加矿物质溶解独立于破骨细胞活化和PTH在这个实验模型的急性饥饿。
Severe chronic undernutrition is associated with decreased bone turnover and significant bone loss. However, little is known about the short-term effects of nutritional deprivation on bone turnover. To investigate the effects of short-term fasting on bone metabolism and the contribution of acidosis to these changes, 14 healthy women ages 18-26 (mean, 21 +/- 2 (SD years) were randomized to potassium bicarbonate (KHCO3, 2 meq/kg/day in divided doses) to prevent acidosis or control (potassium chloride, 25 meq/day) during a complete 4-day fast. Bone turnover was assessed using specific markers of formation [osteocalcin (OC) and Type I procollagen carboxyl-terminal propeptide (PICP)] and resorption [pyridinoline (PYRX) and deoxypyridinoline (DPYRX)]. Serum bicarbonate levels fell significantly from 27.0 +/- 3.2 to 17.3 +/- 2.6 mmol/L (P < 0.01) in the control group and were decreased compared to patients receiving KHCO3 [17.3 +/- 2.6 vs. 23.4 +/- 2.4 mmol/L, (P < 0.001)]. Serum total and ionized calcium increased significantly in the control group [9.1 +/- 0.1 to 9.4 +/- 0.2 mg/dL (P < 0.01) and 1.20 +/- 0.03 to 1.23 +/- 0.03 mmol/L (P < 0.05), respectively], but not in patients receiving KHCO3. In addition, serum parathyroid hormone (PTH) levels decreased from 32 +/- 17 to 16 +/- 10 pg/mL (P < 0.05) and urinary calcium excretion increased [86 +/- 51 to 182 +/- 103 mg/day (P = 0.01)] in the control group, but not in patients receiving KHCO3. Serum osteocalcin (OC) and procollagen carboxyl-terminal propeptide (PICP) levels decreased significantly after 4 days of fasting from 9.1 +/- 3.4 to 5.5 +/- 4.2 ng/mL (P < 0.01) and 121 +/- 21 to 46 +/- 13 ng/mL (P = 0.0001) respectively in the patients receiving bicarbonate, and from 10.1 +/- 3.3 to 4.0 +/- 2.9 ng/mL (P < 0.01) and from 133 +/- 22 to 47 +/- 19 ng/mL (P < 0.001) respectively in the control group. The decrease in osteocalcin and PICP during fasting was comparable in both treatment groups. By contrast, urinary excretion of PYRX and DPYRX did not change significantly in either group with 4 days of fasting. These data are the first to demonstrate that markers of bone formation decline significantly with short-term fasting, independent of changes in acid-base status. By contrast, these data demonstrate a direct effect of acidosis in stimulating calcium release from bone during short-term fasting and suggest that acidosis may increase mineral dissolution independent of osteoclast activation and PTH in this experimental model of acute starvation.