Nanba K, Nagake Y, Miyatake N, Nakao K, Akagi S, Sugimoto T, Yamasaki H, Oishi K, Ichikawa H, Makino H
Department of Medicine III, Okayama University Medical School, Okayama, Japan.
Nephron. 2001 Oct;89(2):145-52. doi: 10.1159/000046061.
Insulinlike growth factor (IGF) I and IGF-II are synthesized in osteoblasts and stimulate proliferation, differentiation, and matrix synthesis in these cells. There is some evidence that IGFs act on bone cells not only by paracrine but also by endocrine pathways, suggesting that circulating IGFs may be of importance for the regulation of bone metabolism. On the other hand, the serum IGF-I level is also thought to be a good indicator of the nutritional conditions in hemodialysis patients. The present study was performed to analyze the correlations of circulating levels of IGF-I, IGF-II, IGF-binding protein (IGFBP) 1 and IGFBP-3 with biochemical markers of bone metabolism and parameters of the urea kinetic model which reflect nutritional conditions in hemodialysis patients. We also examined the differences between these relationships in male and female patients on hemodialysis. Sixty-two hemodialysis patients, 36 men (male group) and 26 women (female group), were included in this study. We measured the serum levels of IGF-I, IGF-II, IGFBP-1, and IGFBP-3. The bone mineral content (BMC) of the radius was measured by dual-energy X-ray absorptiometry. We calculated Kt/V, protein catabolic rate, and percent creatinine generation rate (%CGR). We also examined the relationships between serum levels of IGFs and BMC and the parameters of the urea kinetic model. It was found that the serum levels of IGF-I in the hemodialysis patients were almost the same as those in the control group. However, the serum levels of IGF-II, IGFBP-1, and IGFBP-3 in the hemodialysis patients were significantly higher than those in the control group. In the male group, the serum IGF-I levels showed a significant correlation with both serum intact parathyroid hormone levels and BMC, but no significant correlations between these indices were found in the female group. The serum levels of both IGF-I and IGF-II showed significant correlations with %CGR in the male group, but not in the female group. Stepwise multiple regression analysis was performed to clarify the relationship between serum levels of IGFs and BMC or %CGR. It was found that age, hemodialysis duration, serum intact parathyroid hormone levels, and sex were independent factors associated with BMC. The %CGR was associated independently with serum levels of IGF-I, and IGF-II and with the presence of diabetes mellitus. In conclusion, it is thought that serum levels of IGF-I and IGF-II can be used as indices of nutritional conditions in hemodialysis patients. However, the serum IGF-I level cannot be used as a marker of bone metabolism in hemodialysis patients.
胰岛素样生长因子（IGF）-I和IGF-II在成骨细胞中合成，并刺激这些细胞的增殖、分化和基质合成。有证据表明，IGF不仅通过旁分泌途径作用于骨细胞，还通过内分泌途径发挥作用，这表明循环中的IGF可能对骨代谢调节具有重要意义。另一方面，血清IGF-I水平也被认为是血液透析患者营养状况的良好指标。本研究旨在分析循环中IGF-I、IGF-II、IGF结合蛋白（IGFBP）-1和IGFBP-3水平与骨代谢生化标志物以及反映血液透析患者营养状况的尿素动力学模型参数之间的相关性。我们还研究了血液透析男性和女性患者在这些关系上的差异。本研究纳入了62例血液透析患者，其中36例男性（男性组）和26例女性（女性组）。我们测量了血清中IGF-I、IGF-II、IGFBP-1和IGFBP-3的水平。采用双能X线吸收法测量桡骨的骨矿物质含量（BMC）。我们计算了Kt/V、蛋白质分解代谢率和肌酐生成率百分比（%CGR）。我们还研究了IGF血清水平与BMC以及尿素动力学模型参数之间的关系。结果发现，血液透析患者的血清IGF-I水平与对照组几乎相同。然而，血液透析患者的血清IGF-II、IGFBP-1和IGFBP-3水平显著高于对照组。在男性组中，血清IGF-I水平与血清完整甲状旁腺激素水平和BMC均呈显著相关，但在女性组中未发现这些指标之间存在显著相关性。男性组中IGF-I和IGF-II的血清水平均与%CGR呈显著相关，但女性组中并非如此。进行逐步多元回归分析以阐明IGF血清水平与BMC或%CGR之间的关系。结果发现，年龄、血液透析时间、血清完整甲状旁腺激素水平和性别是与BMC相关的独立因素。%CGR与IGF-I和IGF-II的血清水平以及糖尿病的存在独立相关。总之，认为血清IGF-I和IGF-II水平可作为血液透析患者营养状况的指标。然而，血清IGF-I水平不能用作血液透析患者骨代谢的标志物。
