TGF beta 1 and TGF beta 2 mRNA and protein expression in human bone samples

Transforming growth factor beta is one of the most abundant growth factors stored in bone. It is known as a potent regulator of osteoblast proliferati on and differentiation as well as of production extracellular matrix. We es tablished a highly specific RT-PCR in combination with HPLC for detection a nd quantification of TGF beta1 and TGF beta2 mRNA expression in 89 human ho ne samples. Levels of TGF beta1 protein ranged between 27 and 580 ng/g bone (mean 188 +/- 15 ng/g: n = 75) and for TGF beta2 between 7.2 and 35 ng/g b one (mean 14.3 +/- 2.1 ng/g; n = 57). TGF beta1 and TGF beta2 protein conce ntrations and TGF beta isoform mRNA expression in bone were not significant ly different between the sexes. TGF beta isoform mRNA expression as well as protein content in bone declined age dependently. TGF beta1 and TGF beta2 protein and mRNA expression were different in bone samples from different s ites of the skeleton indicating in part the regulation by mechanical stimul i. In contrast to TGF beta1, TGF beta2 mRNA expression was significantly en hanced in osteoarthritic bone compared to unaffected bone. These data are i n concordance to previous results concerning the expression of TGF beta3 in bone. In conclusion, the data suggest distinct patterns' of expression of the TGF beta isoforms under physiological and pathological conditions in bo ne.