Semiquantitative mRNA measurements of osteoinductive growth factors in XXXX iliac-crest bone: expression of LMP splice variants in @entity1 bone.

@entity1 @entity217 @entity1568 @entity1841 @entity25062 @entity442 @entity10553 @entity11673 @entity5100 @entity12017 @entity540 @entity2533
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 ( @entity25062 , @entity10553 , @entity25062 ) and the established osteotropic growth factors @entity1841 , @entity11673 , @entity12017 , @entity2533 , @entity442 , @entity5100 and @entity540 in @entity1 iliac crest bone. Standardized bone biopsy specimens were obtained from the iliac crest during graft harvesting in 62 @entity1 (38 males, 24 females, mean age 44.7 years, range 13-78 years) undergoing spinal surgery. Samples were immediately stored in liquid @entity1568 for PCR analysis. Semi-quantitative RT-PCR was performed for @entity2533 , @entity442 , @entity5100 , @entity1841 , @entity11673 , @entity12017 , @entity540 , @entity25062 , @entity10553 and @entity25062 using @entity217 as internal standard. Triplicate measurements were made of each growth factor and @entity217 . mRNA for all examined growth factors was detected in 69% of the specimens. The lowest degree of detection was present for @entity540 and @entity1841 , both of which were found in 85% of the specimens. @entity25062 was detected in 98% of the specimens. @entity10553 in 94% and @entity25062 in 27%, respectively. @entity25062 was generally expressed in higher amounts than @entity10553 and @entity25062 . 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). @entity25062 expression was more variable among young individuals, but mean values were similar between age groups. @entity2533 , @entity1841 and @entity12017 values did not differ between age groups, but generally a higher variation was found among older @entity1 . @entity442 values were significantly higher ( P < 0.05) in males over 60 years, whereas the highest level of @entity540 mRNA was present in males younger than 20 years ( P < 0.05). In addition, regression analysis revealed correlation between @entity1841 and @entity12017 (R2 = 0.74, P < 0.0005), @entity10553 and @entity1841 (R2 = 0.27, P < 0.0005) and @entity10553 and @entity540 (R2 = 0.40, P < 0.0005). In conclusion, we have demonstrated expression of @entity25062 and @entity10553 in @entity1 bone. @entity25062 was expressed in higher amounts and showed a higher degree of variation among young individuals. @entity10553 was correlated to a number of other growth factors, suggesting that LMPs may also play a role in @entity1 bone metabolism. Higher variation in the expression of @entity2533 , @entity1841 and @entity12017 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.
