Valproic acid (VPA) has been used as an anticonvulsant agent for the treatment of epilepsy, as well as a mood stabilizer for the treatment of bipolar disorder, for several decades. The mechanism of action for these effects remains to be elucidated and is most likely multifactorial. Recently, VPA has been reported to inhibit histone deacetylase (HDAC) and HDAC has been reported to play roles in differentiation of mammalian cells. In this study, the effects of HDAC inhibitors on differentiation and proliferation of human adipose tissue-derived stromal cells (hADSC) and bone marrow stromal cells (hBMSC) were determined. VPA increased osteogenic differentiation in a dose dependent manner. The pretreatment of VPA before induction of differentiation also showed stimulatory effects on osteogenic differentiation of hMSC. Trichostatin A (TSA), another HDAC inhibitor, also increased osteogenic differentiation, whereas valpromide (VPM), a structural analog of VPA which does not possess HDAC inhibitory effects, did not show any effect on osteogenic differentiation on hADSC. RT-PCR and Real-time PCR analysis revealed that VPA treatment increased osterix, osteopontin, BMP-2, and Runx2 expression. The addition of noggin inhibited VPA-induced potentiation of osteogenic differentiation. VPA inhibited proliferation of hADSC and hBMSC. Our results suggest that VPA enhance osteogenic differentiation, probably due to inhibition of HDAC, and could be useful for in vivo bone engineering using hMSC.
The lumbosacral area is one of the most frequently operated spine regions because of the prevalence of disease in that area. Although a lumbosacral soft tissue defect after surgery due to inflammation and other causes is rare, such soft tissue defects are difficult to treat. Therefore, suitable methods for treating lumbosacral soft tissue defects are necessary. Therefore, this study introduces a case-treated with a transverse lumbosacral rotational flap.
To assess the midterm results of the hydroxyapatite hip system with acetabular cups, with particular emphasis upon cup wear and loosening, using a computer assisted-3 dimensional technique. Materials and Methods: From March 1992 to December 1996, 52 patients (61 hips) were available for inclusion in this study after an average duration of follow up of 6 years and 4 months. Clinical evaluation was performed using the Harris hip scoring system. Initial postoperative and long term follow up films were digitized, and 2 dimensional linear and 3 dimensional wear was measured by using a computer assisted-3 dimensional technique. Acetabular bone changes are described using previous published methods. Results: An analysis of the clinical results showed a mean Harris hip score of 47.2 points preoperatively and 89.8 points at the final visit. The mean polyethylene 3D-linear wear rate was 0.26 mm/year and mean volumetric wear rate was 105.9 mm 3 /year. In 16 hips (26.2%) the linear wear rate was more than 0.3 mm/year (0.30-0.74 mm/year). Osteolytic changes of the acetabulum were recorded in 51% around acetabular cups, in which considerable wear of the acetabular polyethylene was evident by the five-year radiographic findings. Conclusion: Midterm results of hydroxyapatite coated acetabular cups were disappointing in terms of acetabular cup and liner wear, despite early accelerated bone remodeling by hydroxyapatite and excellent early clinical results.
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