Kerschan-Schindl K, Hawa G, Kudlacek S, Woloszczuk W, Pietschmann P
Department of Physical Medicine and Rehabilitation, University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
Exp Gerontol. 2005 Jun;40(6):532-5. doi: 10.1016/j.exger.2005.04.001.
Bone turnover increases with age. In a previous study, we reported on bone metabolism in young and elderly women and men. The aim of the present investigation was to evaluate potential age- and gender-related changes in cathepsin K, a cysteine protease that plays an important role in the degradation of the organic matrix of bone. Twenty-five healthy premenopausal women, 24 young healthy men, 26 elderly women, and 25 elderly men participated in the study. Elderly women and men had significantly lower cathepsin K levels than younger ones. In both men and women, serum levels of cathepsin K were negatively correlated with age. In men there was a statistically significant negative correlation between serum levels of cathepsin K and osteoprotegerin, which inhibits osteoclast differentiation and activation. No association was found between serum levels of cathepsin K and bone-specific alkaline phosphatase, osteocalcin, or 25-hydroxy vitamin D. Thus, the age-related increase in OPG, which markedly inhibits the expression of cathepsin K, may also reduce serum levels of cathepsin K. Despite the age-related increase in bone resorption, this study shows lower cathepsin K values in elderly women and men than in younger subjects. It might be speculated that a different enzyme could compensate for the decline in cathepsin K during old age.
骨转换随年龄增长而增加。在之前的一项研究中，我们报道了年轻和老年女性及男性的骨代谢情况。本研究的目的是评估组织蛋白酶K中潜在的年龄和性别相关变化，组织蛋白酶K是一种半胱氨酸蛋白酶，在骨有机基质的降解中起重要作用。25名健康的绝经前女性、24名年轻健康男性、26名老年女性和25名老年男性参与了该研究。老年女性和男性的组织蛋白酶K水平明显低于年轻人。在男性和女性中，组织蛋白酶K的血清水平均与年龄呈负相关。在男性中，组织蛋白酶K的血清水平与抑制破骨细胞分化和激活的骨保护素之间存在统计学上显著的负相关。未发现组织蛋白酶K的血清水平与骨特异性碱性磷酸酶、骨钙素或25-羟基维生素D之间存在关联。因此，显著抑制组织蛋白酶K表达的骨保护素随年龄增长而增加，这也可能会降低组织蛋白酶K的血清水平。尽管骨吸收随年龄增长而增加，但本研究显示老年女性和男性的组织蛋白酶K值低于年轻受试者。可以推测，在老年时期可能有不同的酶来补偿组织蛋白酶K的下降。
