[Perspectives of clinical stem cell therapy in the treatment of musculoskeletal diseases in Germany]. / Perspektiven klinischer mesenchymaler Stammzelltherapie bei muskuloskeletalen Erkrankungen in Deutschland.

AIM: The treatment of large bone defects remains a challenge for the orthopaedic surgeon. Regenerative therapies with the use of mesenchymal stem cells (MSC) may provide an alternative to autogenous bone transplantation, callus distraction or the use of allografts. MATERIAL AND METHODS: On the occasion of an expert workshop of the German Society for Orthopaedic and Trauma Surgery, a literature search regarding studies with the use of MSC was performed to evaluate its potential for future clinical studies. Furthermore, the legislative requirements were examined. RESULTS: Various in vitro and animal studies showed the benefit of MSC in bone regeneration. However, there are sparse data from clinical studies. Due to recent legislative changes there are several regulatory demands to meet if clinical studies are performed with MSC. CONCLUSIONS: For further evaluation of the role of MSC in the treatment of bone defects there is a need for clinical trials. The current paper provides some assistance for the successful application for clinical trials with MSC. Planning and performance of these studies may require early consultation with the regulatory authorities and cooperation of research centres in order to obtain authorisation for the evaluation of MSC. Preclinical data have to be obtained according to good laboratory practice with equivalent protocols that will be used in the clinical trials. In the latter the implementation of the guidelines for good clinical practice are mandatory.

[Induction of bone tissue on different matrices: an in vitro and a in vivo pilot study in the SCID mouse]. / Induktion von Knochengewebe auf unterschiedlichen Matrizes: Eine In-vitro- und In-vivo-Pilotstudie in der SCID Maus.

AIM: Three resorbable biomaterials were evaluated regarding proliferation and osteogenic differentiation of human bone marrow stromal cells (BMSC) in vitro. In a second step, the new biomaterial, calcium-deficient hydroxyapatite (CDHA), was tested in a pilot in vivo study by subcutaneous implantation in the severe combined immunodeficiency (SCID) mouse. METHODS: CDHA, beta-tricalcium phosphate (beta-TCP), and demineralized bone matrix (DBM) were seeded with human BMSC and cultured in osteogenic supplements for 3 weeks. In the pilot in vivo study, CDHA was seeded with BMSC and kept in osteogenic media for 2 weeks (group A) before subcutaneous implantation in 8 SCID mice for 3 and 8 weeks. In addition, CDHA seeded with BMSC without prior osteogenic induction (group B) and empty ceramics were implanted in each mouse. RESULTS: Total protein content and the values for specific alkaline phosphatase (ALP) increased significantly in vitro on all matrices, but no significant difference between the groups was noted. In the pilot in vivo study all ceramics were well penetrated by cells. After 8 weeks 2 of 4 samples in group B and 1 of 4 samples in group A revealed cells resembling hypertrophic chondrocytes. Specific ALP was higher in the group B (p = 0.012, Z = - 2.5) compared to empty ceramics. There were no significant differences between groups A and B. Differences between group A and the empty control did not become significant (p = 0.069, Z = - 1.8). CONCLUSION: All three matrices promoted BMSC proliferation and differentiation to osteogenic cells in vitro. Human BMSC on CDHA showed signs of osteogenic differentiation after subcutaneous implantation into SCID mice.

Comparison of human bone marrow stromal cells seeded on calcium-deficient hydroxyapatite, beta-tricalcium phosphate and demineralized bone matrix.

The aim of this study was to compare three resorbable biomaterials regarding seeding efficacy with human bone marrow stromal cells (BMSCs), cell penetration into the matrix, cell proliferation and osteogenic differentiation. Calcium-deficient hydroxyapatite (CDHA), beta-tricalcium phosphate (beta-TCP), and demineralized bone matrix (DBM) were seeded with human BMSCs and kept in human serum and osteogenic supplements for 3 weeks. Morphologic and biochemical evaluations were performed on day 1, 7, 14 and 21. The allograft DBM and CDHA exhibited both an excellent seeding efficacy while the performance of beta-TCP was lower when compared. The total protein content and the values for specific alkaline phosphatase (ALP) increased on all matrices and no significant difference was found for these two markers. BMSCs in monolayer had a significant increase of protein, but not of ALP. Osteocalcin (OC) values increased significantly higher for BMSC in cultures on DBM when compared to CDHA and beta-TCP. The OC levels decreased significantly in the BMSC monolayer culture. BMSCs were found inconsistently within the synthetic materials, whereas in DBM they were found more homogeneously distributed throughout the matrix. All three matrices promoted BMSC proliferation and differentiation to osteogenic cells. DBM allografts seem to be more favorable with respect to cell ingrowth tested by histology, and osteogenic differentiation ascertained by an increase of OC. CDHA with its high specific surface area showed more favorable properties than beta-TCP regarding reproducibility of the seeding efficacy.