Abstract

Summary

PTH levels might be associated with bone material strength as measured by impact microindentation. Resistance to microfracture is decreased in hypoparathyroidism and appears to be associated with more severe disease and to improve with PTH replacement.

Introduction

PTH is a key regulator of bone structure and remodeling. When PTH is absent in hypoparathyroidism (HypoPT), bone mass is increased and remodeling is decreased. In addition to bone structure and remodeling, bone material properties contribute to fracture resistance. Yet little is known about the relationship between PTH and bone material properties. Impact microindentation provides a clinical assessment of microfracture resistance, measured as the bone material strength index (BMSi).

Methods

Case-control cross-sectional study of PTH levels and in vivo BMSi measurement by impact microindentation at the anterior tibia in HypoPT patients (n = 17) and in controls matched for age, sex, and menopausal status (n = 17), with follow-up in a subgroup of HypoPT patients (n = 5) after recombinant human parathyroid hormone (1-84) [rhPTH(1-84)] treatment.

Results

BMSi was positively associated with PTH levels in controls (r = 0.58, p = 0.02) and was 11% lower (p = 0.01) in HypoPT patients as compared with controls. In HypoPT, lower BMSi was associated with a trend toward greater supplemental calcium doses (p = 0.07). BMSi increased after rhPTH(1-84) treatment in the HypoPT patients who underwent repeat microindentation.

Conclusions

PTH levels might be associated with bone material strength, although other factors might be contributory. In HypoPT, resistance to microfracture is decreased and may be associated with greater supplemental calcium doses and might increase with PTH replacement. It remains to be determined whether changes in bone remodeling and microarchitecture contribute to the effects of PTH on microfracture resistance.

中文翻译：

---

甲状旁腺功能减退症的PTH和骨材料强度（通过冲击微压痕测量）

摘要

概要

PTH水平可能与通过冲击微压痕测量的骨材料强度有关。甲状旁腺功能低下对微骨折的抵抗力降低，似乎与更严重的疾病有关，并随着PTH的替代而改善。

介绍

PTH是骨骼结构和重塑的关键调节剂。当甲状旁腺功能减退症（HypoPT）中不存在PTH时，骨量增加而重塑减少。除了骨骼结构和重塑之外，骨骼的材料特性也有助于抗断裂性。关于PTH和骨骼材料属性之间的关系知之甚少。冲击微压痕提供了抗微断裂性的临床评估，以骨材料强度指数（BMSi）衡量。

方法

通过冲击微压痕在HypoPT例（前胫骨PTH水平的和体内BMSI测量病例对照横断面研究Ñ = 17）和在对年龄，性别，和绝经状态（匹配的对照Ñ = 17），与后续重组人甲状旁腺激素（1-84）[rhPTH（1-84）]治疗后的HypoPT患者亚组（n = 5）

结果

与对照组相比，BMSi与对照组的PTH水平呈正相关（r = 0.58，p = 0.02），与HypoPT患者相比，BMSi降低11％（p = 0.01）。在HypoPT中，较低的BMSi与增加钙补充剂量的趋势相关（p = 0.07）。接受重复微压痕的HypoPT患者在rhPTH（1-84）治疗后BMSi升高。

结论

PTH水平可能与骨骼材料强度有关，尽管其他因素也可能是造成这种情况的原因。在HypoPT中，对微骨折的抵抗力降低，可能与更大的补充钙剂量有关，并可能随着PTH的替代而增加。骨重塑和微结构的变化是否会影响PTH对微骨折抵抗性的影响尚待确定。