Semiquantitative mRNA Measurements of Osteoinductive Growth Factors in Human Iliac-Crest Bone: Expression of LMP Splice Variants in Human Bone
Semiquantitative mRNA Measurements of Osteoinductive Growth Factors in Human Iliac-Crest Bone: Expression of LMP Splice Variants in Human Bone
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DOI：
10.1007/s00223-002-2109-z
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发表时间：
2003-09
影响因子：
4.2
通讯作者：
M. Bünger;B. Langdahl;T. Andersen;L. Husted;M. Lind;E. Eriksen;C. Bünger
中科院分区：
文献类型：
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作者：
M. Bünger;B. Langdahl;T. Andersen;L. Husted;M. Lind;E. Eriksen;C. Bünger
虽然已知促骨生长因子在骨代谢中起重要作用，但关于其表达与年龄、性别和吸烟的关系的知识仍然有限。在这项研究中，我们报告了最近发现的Lim矿化蛋白剪接变体（LMP-1，LMP-2，LMP-3）和已建立的骨生长因子BMP-2，BMP-6，BMP-7，TGF-β，IGF-I，IGF-II和b-FGF在人髂嵴骨中的mRNA水平。在62例接受脊柱手术的患者（38例男性，24例女性，平均年龄44.7岁，范围13-78岁）的移植物采集期间，从髂嵴获得标准化骨活检标本。将样品立即储存在液氮中用于PCR分析。以β-actin为内标，对TGF-β、IGF-I、IGF-II、BMP-2、BMP-6、BMP-7、bFGF、LMP-1、LMP-2和LMP-3进行半定量RT-PCR。对每种生长因子和β-肌动蛋白进行三次测量。在69%的标本中检测到所有检查的生长因子的mRNA。b-FGF和BMP-2的检出率最低，两者均见于85%的标本。在98%的标本中检测到LMP-1。LMP-2为94%，LMP-3为27%。LMP-1的表达量通常高于LMP-2和LMP-3。>60岁男性患者生长因子水平低于>60岁女性患者（P< 0.05）和<60岁男性患者（P< 0.01）。LMP-1表达在年轻个体中变化更大，但年龄组之间的平均值相似。TGF-β、BMP-2和BMP-7值在不同年龄组之间没有差异，但通常在老年患者中发现更高的变化。60岁以上的男性IGF-I值显著高于60岁以上的男性（P< 0.05），而20岁以下的男性bFGF mRNA水平最高（P< 0.05）。回归分析显示BMP-2与BMP-7（R2= 0.74，P < 0.0005）、LMP-2与BMP-2（R2= 0.27，P < 0.0005）、LMP-2与bFGF（R2= 0.40，P < 0.0005）相关。总之，我们已经证明了LMP-1和LMP-2在人骨中的表达。LMP-1的表达量较高，并且在年轻个体中表现出较高的变异程度。LMP-2与许多其他生长因子相关，表明LMP也可能在人类骨代谢中发挥作用。TGF-β、BMP-2和BMP-7的表达在老年组中存在较高的变化，但这是否与骨转换的年龄相关变化相关还需要进一步研究。
Although osteotropic growth factors are known to play an important role in bone metabolism, knowledge about their expression in relation to age, sex and smoking remains limited. In this study we report mRNA levels of the recently discovered Lim mineralization protein splice variants (LMP-1, LMP-2, LMP-3) and the established osteotropic growth factors BMP-2, BMP-6, BMP-7, TGF-β, IGF-I, IGF-II and b-FGF in human iliac crest bone. Standardized bone biopsy specimens were obtained from the iliac crest during graft harvesting in 62 patients (38 males, 24 females, mean age 44.7 years, range 13–78 years) undergoing spinal surgery. Samples were immediately stored in liquid nitrogen for PCR analysis. Semi-quantitative RT-PCR was performed for TGF-β, IGF-I, IGF-II, BMP2, BMP-6, BMP7, bFGF, LMP-1, LMP-2 and LMP-3 using β-actin as internal standard. Triplicate measurements were made of each growth factor and β-actin. mRNA for all examined growth factors was detected in 69% of the specimens. The lowest degree of detection was present for b-FGF and BMP-2, both of which were found in 85% of the specimens. LMP-1 was detected in 98% of the specimens. LMP-2 in 94% and LMP-3 in 27%, respectively. LMP-1 was generally expressed in higher amounts than LMP-2 and LMP-3. Nondetectable levels of the growth factors were more frequent in the >60-year-old males compared with >60-year-old females (P< 0.05) and <60-year-old males (P< 0.01). LMP-1 expression was more variable among young individuals, but mean values were similar between age groups. TGF-β, BMP-2 and BMP-7 values did not differ between age groups, but generally a higher variation was found among older patients. IGF-I values were significantly higher (P< 0.05) in males over 60 years, whereas the highest level of bFGF mRNA was present in males younger than 20 years (P< 0.05) . In addition, regression analysis revealed correlation between BMP-2 and BMP-7 (R2= 0.74,P< 0.0005), LMP-2 and BMP-2 (R2= 0.27,P< 0.0005) and LMP-2 and bFGF (R2= 0.40,P< 0.0005). In conclusion, we have demonstrated expression of LMP-1 and LMP-2 in human bone. LMP-1 was expressed in higher amounts and showed a higher degree of variation among young individuals. LMP-2 was correlated to a number of other growth factors, suggesting that LMPs may also play a role in human bone metabolism. Higher variation in the expression of TGF-β, BMP-2 and BMP-7 was found in the older age groups, but whether or not this can be correlated to age-related changes in bone turnover requires further studies.