of treatment demonstrated effective anticoagulation achieved in the dabigatran treated rats. Results of the hemoclot -assay indicated a dabigatran plasma concentration of 317.330.1 nmol/l. 5 / 15 Dabigatran vs. Warfarin Effects on Bone Fig 2. Dabigatran preserves femur volume and structure. Note the higher bone volume and trabecular thickness with lesser trabecular separation in rats treated with dabigatran compared to rats treated with warfarin. Bone of a representative normal control rat is also shown.. doi:10.1371/journal.pone.0133847.g002 Vascular Calcifications Under our experimental conditions, there was no evidence of arterial calcium deposition either in the aorta or in the iliac arteries among the three groups of rats. Bone Histomorphometry Ten rats treated with dabigatran and ten control rats were available for histomorphometric analysis, while in warfarin treated group the analysis was performed on seven surviving rats. Analysis of proximal PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19747074 femur. Parameters of structure showed decreased bone volume and increased trabecular separation in rats treated with warfarin with respect to dabigatran treated and control rats. Reduced osteoblast activity was detected in warfarin treated group. In addition, treatment with warfarin was associated with increased turnover, characterized by increased resorption parameters and higher BFR/BS as a result of a similar MAR with increased MS/BS. Consistently with these results, activation frequency was also higher in warfarin treated group than in dabigatran treated and control rats. There were no Triptolide chemical information substantial differences in microarchitecture among groups, with similar node number/tissue volume, marrow star volume, and fractal dimension and a little difference in node/termini ratio. Analysis of Vertebrae. The analysis of bone structure showed significant decreases in bone volume and increases in trabecular separation in rats treated with warfarin compared to dabigatran treated and control rats. In addition, trabecular number was lower in the warfarin treated group than in the dabigatran group. Concerning the remodelling, we observed significant difference in osteoblast activity and resorption parameters associated to higher Ac.F in warfarin-treated groups vs both others, suggesting that warfarin may cause an increased turnover PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19747545 characterized by increased remodelling cycles, with increased osteoclast activity with respect to other groups. No substantial differences in microarchitecture, were observed among groups, even though there was a tendency towards altered microarchitecture parameters with warfarin treatment. Thus, in the vertebrae, treatment with warfarin decreased bone volume with increased trabecular separation as a result of increased turnover and osteoclast activity, while treatment with dabigatran maintained the parameters of structure and turnover similar to those in the control group, showing, as a result, a bone sparing effect versus warfarin. 6 / 15 Dabigatran 
vs. Warfarin Effects on Bone Fig 3. Significant histomorphometric results of structural and dynamic parameters in femur rats. In warfarin treated rats we observed lower bone volume and trabecular thickness with increased trabecular separation compared to dabigatran treated and control rats. In addition, treatment with warfarin was associated with a significant increase of turnover parameters and, in particular, activation frequency was higher in warfarin treated rats versus dabigatran treated or control rats. Microarchitecture,