Boric acid and Molybdenum trioxide synergistically stimulate osteogenic differentiation of human bone marrow-derived mesenchymal stromal cells.

INTRODUCTION: Metals and their metal ions have been shown to exhibit certain biological functions that make them attractive for use in biomaterials, for example in bone tissue engineering (BTE) applications. Recent data shows that Molybdenum (Mo) is a potent inducer of osteogenic differentiation in human bone marrow-derived mesenchymal stromal cells (BMSCs). On the other hand, while boron (B) has been shown to enhance vascularization in BTE applications, its impact on osteogenic differentiation is volatile: while improved osteogenic differentiation has been described, other data show that B might slow down osteogenic differentiation or reduce the calcification of the extracellular matrix (ECM) when applied in higher doses. Still, the combination of pro-osteogenic Mo and pro-angiogenic B is certainly attractive in the context of biomaterials intended for the use in BTE. METHODS: Therefore, the combined effect of molybdenum trioxide and boric acid at different ratios was investigated in this study to evaluate the effects on the viability, proliferation, osteogenic differentiation, ECM production and maturation of BMSCs. RESULTS: Mo ions proved to be stronger osteoinductive compared to B, in fact, while some osteogenic differentiation markers were downregulated in the presence of B, the presence of Mo provided compensation. The combined application of B and Mo indicated a combination of individual effects, partially even enhancing the expected combined performance of the single stimulations. CONCLUSIONS: The combination of B and Mo might be beneficial for BTE applications since the limited osteogenic properties of B can be compensated by Mo. Furthermore, since B is known to be pro-angiogenic, the combination of both substances may synergistically lead to improved vascularization and bone regeneration. Future studies should assess the angiogenic performance of this combination in greater detail.

[Treatment of unicompartmental osteoarthritis of the knee]. / Therapie der unikompartimentellen Gonarthrose.

Osteoarthritis of the knee is one of the most important degenerative joint diseases in the clinical routine. The treatment of knee osteoarthritis is not only based on the stage, symptoms and duration of the joint disease, but also depends on the existing arthrosis pattern. In the case of unicompartmental arthrosis, damage typical for osteoarthritis is limited to just one joint compartment. Both the conservative and the surgical treatment of unicompartmental osteoarthritis of the knee have to respect the individual characteristics of the respective forms of osteoarthritis. In the context of this manuscript, the genesis, the diagnostics and the guideline-based stage-adapted conservative and operative treatment of unicompartmental osteoarthritis of the knee are addressed.

Molybdenum trioxide enhances viability, osteogenic differentiation and extracellular matrix formation of human bone marrow-derived mesenchymal stromal cells.

BACKGROUND: Metals and their ions allow specific modifications of the biological properties of bioactive materials that are intended for application in bone tissue engineering. While there is some evidence about the impact of particles derived from orthopedic Cobalt-Chromium-Molybdenum (Co-Cr-Mo) alloys on cells, there is only limited data regarding the influence of the essential trace element Mo and its ions on the viability, osteogenic differentiation as well as on the formation and maturation of the primitive extracellular matrix (ECM) of primary human bone marrow-derived stromal cells (BMSCs) available so far. METHODS: In this study, the influence of a wide range of molybdenum (VI) trioxide (MoO3), concentrations on BMSC viability was evaluated via measurement of fluorescein diacetate metabolization. Thereafter, the impact of three non-cytotoxic concentrations of MoO3 on the cellular osteogenic differentiation as well as on ECM formation and maturation of BMSCs was assessed. RESULTS: MoO3 had no negative influence on BMSC viability in most tested concentrations, as viability was in fact even enhanced. Only the highest concentration (10 mM) of MoO3 showed cytotoxic effects. Cellular osteogenic differentiation, measured via the marker enzyme alkaline phosphatase was enhanced by the presence of MoO3 in a concentration-dependent manner. Furthermore, MoO3 showed a positive influence on the expression of relevant marker genes for osteogenic differentiation (osteopontin, osteocalcin and type I collagen alpha 1) and on the formation and maturation of the primitive ECM, as measured by collagen deposition and ECM calcification. CONCLUSION: MoO3 is considered as an attractive candidate for supplementation in biomaterials and qualifies for further research.

Ionic dissolution products of Cerium-doped bioactive glass nanoparticles promote cellular osteogenic differentiation and extracellular matrix formation of human bone marrow derived mesenchymal stromal cells.

Cerium (Ce) is a promising candidate ion for application in bone tissue engineering (BTE) since it reduces the presence of reactive oxygen species. Ce-doped mesoporous bioactive glass nanoparticles (MBGNs) serving as vectors for the local application of Ce already demonstrated stimulating effects on the expression of pro-osteogenic genes in Saos-2 cells. So far, there is no evidence available about the effects of Ce-doped MBGNs on the viability, osteogenic differentiation and the formation of the osseous extracellular matrix (ECM) of primary human bone marrow-derived mesenchymal stromal cells (BMSCs). Therefore, in this study, the biocompatibility of the ionic dissolution products (IDPs) of MBGNs containing increasing concentrations of CeO2(0.05 MCe-MBGNs, composition in mol%: 86.6SiO2-12.1CaO-1.3CeO2; and 0.2 MCe-MBGNs, composition in mol%: 86.0SiO2-11.8CaO-2.2CeO2) and unmodified MBGNs (composition in mol%: 86SiO2-14CaO) was evaluated using human BMSCs. Eventually, the impact of the MBGNs' IDPs on the cellular osteogenic differentiation and their ability to build and mature a primitive osseous ECM was assessed. The Ce-doped MBGNs had a positive influence on the viability and stimulated the cellular osteogenic differentiation of human BMSCs evaluated by analyzing the activity of alkaline phosphate as a marker enzyme for osteoblasts in the present setting. Furthermore, the formation and calcification of a primitive osseous ECM was significantly stimulated in the presence of Ce-doped MBGNs in a positive concentration-dependent manner as demonstrated by an elevated presence of collagen and increased ECM calcification. The results of thisin-vitrostudy show that Ce-doped MBGNs are attractive candidates for further application in BTE.

Superior biocompatibility and comparable osteoinductive properties: Sodium-reduced fluoride-containing bioactive glass belonging to the CaO-MgO-SiO2 system as a promising alternative to 45S5 bioactive glass.

Bioactive glasses (BGs) are promising bone substitute materials. However, under certain circumstances BGs such as the well-known 45S5 Bioglass® (composition in wt%: 45.0 SiO2, 24.5 Na2O, 24.5 CaO, 6.0 P2O5) act cytotoxic due to a strong increase in pH caused by a burst release of sodium ions. A potential alternative is a sodium-reduced fluoride-containing BG belonging to the CaO-MgO-SiO2 system, namely BG1d-BG (composition in wt%: 46.1 SiO2, 28.7 CaO, 8.8 MgO, 6.2 P2O5, 5.7 CaF2, 4.5 Na2O), that has already been evaluated in-vitro, in-vivo and in preliminary clinical trials. Before further application, however, BG1d-BG should be compared to the benchmark amongst BGs, the 45S5 Bioglass® composition, to classify its effect on cell viability, proliferation and osteogenic differentiation of human mesenchymal stem cells (MSCs). Therefore, in this study, the biocompatibility and osteogenic potential of both BGs were investigated in an indirect and direct culture setting to assess the effect of the ionic dissolution products and the BGs' physical presence on the cells. The results indicated an advantage of BG1d-BG over 45S5 Bioglass® regarding cell viability and proliferation. Both BGs induced an earlier onset of osteogenic differentiation and accelerated the expression of late osteoblast marker genes compared to the control group. In conclusion, BG1d-BG is an attractive candidate for further experimental investigation. The basic mechanisms behind the different impact on cell behavior should be assessed in further detail, e.g. by further alteration of the BG compositions.

Favorable angiogenic properties of the borosilicate bioactive glass 0106-B1 result in enhanced in vivo osteoid formation compared to 45S5 Bioglass.

The 45S5-bioactive glass (BG) composition is the most commonly investigated amongst BG-based bone substitutes. By changing BG compositions and by addition of therapeutically active ions such as boron, the biological features of BGs can be tailored towards specific needs and possible drawbacks can be overcome. The borosilicate glass 0106-B1 (composition in wt%: 37.5 SiO2, 22.6 CaO, 5.9 Na2O, 4.0 P2O5, 12.0 K2O, 5.5 MgO, 12.5 B2O3) has demonstrated pro-angiogenic properties. However, the osteogenic performance of the 0106-B1-BG and its influence on cell viability and proliferation in vitro as well as its osteogenic and angiogenic properties in vivo have not been investigated. Therefore, in this study, the impact of 0106-B1-BG and 45S5-BG on osteogenic differentiation, viability and proliferation on human mesenchymal stromal cells (MSCs) was assessed in vitro. Furthermore, MSC-seeded scaffolds made from both BG types were implanted subcutaneously in immunodeficient mice for 10 weeks. Osteoid formation was quantified by histomorphometry, vascularization was visualized by immunohistological staining. Additionally, the in vivo expression patterns of genes correlating with osteogenesis and angiogenesis were analyzed. In vitro, the impact of 45S5-BG and 0106-B1-BG on the proliferation, viability and osteogenic differentiation of MSCs was comparable. In vivo, scaffolds made from 0106-B1-BG significantly outperformed the 45S5-BG-based scaffolds regarding the amount and maturation of the osteoid. Furthermore, 0106-B1-BG-based scaffolds showed significantly increased angiogenic gene expression patterns. In conclusion, the beneficial angiogenic properties of 0106-B1-BG result in improved osteogenic properties in vivo, making the 0106-B1-BG a promising candidate for further investigation, e.g. in a bone defect model.

Use of Masquelet technique in treatment of septic and atrophic fracture nonunion.

BACKGROUND: Treatment of atrophic non-unions and large bone defects or infections remains a challenging task for the treating surgeon. In the herein study, we present our experience of the 'Masquelet technique' according to the 'diamond concept' for the treatment of complex long bone reconstruction procedures. METHODS: Between February 2010 and March 2015, 150 patients (mean age 51.4) with atrophic and- /or infected non-unions were included in this prospective study. All patients received autologous bone graft, a graft expander (TCP (tricalcium phosphate)) and BMP (bone morphogenic protein). Clinical and radiological parameters were assessed at 6 weeks, and at 3, 6 and 12 months. The SF-12 questionnaire was used to evaluate the subjective health of patients. RESULTS: A successful bony consolidation of the non-unions was observed in 120 (80%) cases with a median healing time of 12.1 months. The mean defect gap was 4.4cm. Initial infection was documented in 54 cases. The most frequently identified pathogen was staphylococcus epidermidis and staphylococcus aureus. A successful removal of microorganisms with subsequent healing was achieved in 39 cases (72%). The SF-12 scores of subjective physical and mental health increased from PCS 31.5 preoperatively to 36.7 one year postoperatively, while MCS increased from 45.5 to 48.7. CONCLUSIONS: Our study showed that the Masquelet technique according to the 'diamond concept' is a valid method to treat complex atrophic non-unions with large bone defects and associated infection. Following the principles of the 'diamond concept' (targeted optimization of tissue engineering and bone regeneration) a high rate of success can be expected in these difficult reconstruction cases.

Knock-down of oncohistone H3F3A-G34W counteracts the neoplastic phenotype of giant cell tumor of bone derived stromal cells.

Giant cell tumors of bone (GCTB) are semi-malignant tumors associated with extensive osteolytic defects and massive bone destructions. They display a locally aggressive behavior and a very high recurrence rate. Recently, a single mutation has been identified in GCTB affecting the H3F3A gene coding for the histone variant H3.3 (H3.3-G34W). The aim of this study was to investigate whether H3.3-G34W is sufficient to drive tumorigenesis in GCTB. Initially, we confirmed the high frequency of this mutation in 94% of 84 analyzed tissue samples. Using a siRNA based approach we could selectively knockdown H3.3-G34W in primary neoplastic stromal cells isolated from tumor tissue (GCTSC). H3.3-G34W knockdown caused a significant inhibition of cell proliferation, migration and colony formation capacity in vitro. Xenotransplantation of GCTSCs onto the chorioallantoic membrane of fertilized chicken eggs further demonstrated a significant impact of H3.3-G34W knockdown on tumor engraftment and growth in vivo. Our data indicate that H3.3-G34W is sufficient to drive tumorigenesis in GCTB. Apart from the application of H3.3-G34W screening as diagnostic tool, our data suggest that H3.3-G4W represents a promising target for the development of new GCTB therapies.

Options and limits of angle stable plates in the treatment of comminuted radial head fractures.

OBJECTIVE: New angle-stable plates provide more stability and better anatomical fit than previous plates. METHODS: 22 patients treated with an angle-stable plate were included. Postoperative the outcomes were evaluated according to the scoring systems of Morrey, Radin and Riseborough. RESULTS: 3 patients received a score of excellent, 14 good, and 5 satisfactory. We detected 3 cases of implant failure and 2 cases of postoperative neurological damage. 3 patientes received a radial head necrosis. CONCLUSIONS: Our results show that the angle-stable radial head locking plate can only be used in limited cases in the treatment of multi-fragment radial head fractures.

Combining advantages: Direct correlation of two-dimensional microcomputed tomography datasets onto histomorphometric slides to quantify three-dimensional bone volume in scaffolds.

Microcomputed tomography (mCT) belongs to the most powerful tools for the three-dimensional (3D) assessment of bone. While it is possible to refer to landmarks in mCT scans of actual bone structure, the assessment of calcified osteoid within scaffolds is problematic, due to the missing morphological correlates. Therefore, bone formation within scaffolds is mostly analyzed using indirect parameters such as changes in volume or surface alteration, preserving histomorphometry the gold standard in the direct analysis of bone formation. The presented method combines the advantages of mCT and histomorphometry: by creating an overlay image of the exact same histomorphometric and mCT slice, a grey-value-threshold representing calcified tissue was defined. Compared to the scaffolds global threshold, a direct evaluation of bone formation within scaffolds is possible by mCT-applied on the whole dataset, evaluation of bone volume is achievable. Two groups of human mesenchymal-stem-cell-seeded ß-Tricalciumphosphate-scaffolds were analyzed: whilst group B was stimulated with 0.1 µg/mL Bone Morphogenetic Protein-7, group A remained unstimulated during in vivo differentiation. Strong correlations (r > 0.8) were obtained between percentage bone area in mCT and histomorphometry, as well as for 3D bone volume. Using the presented method, 3D bone volume can be directly estimated within scaffolds by combination of histomorphometric and mCT-analysis. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1812-1821, 2018.

A pilot study on temporal changes in IL-1ß and TNF-α serum levels after spinal cord injury: the serum level of TNF-α in acute SCI patients as a possible marker for neurological remission.

STUDY DESIGN: Serum levels of interleukin-1ß (IL-1ß) and tumour necrosis factor-α (TNF-α) were measured over a 12-week period in 23 patients with spinal cord injury (SCI) with and without neurological improvement. OBJECTIVES: To determine the course of IL-1ß and TNF-α in patients with SCI and observe a possible relationship between improvements in neurological functioning and cytokine levels. SETTING: All patients were treated at the BG Trauma Centre, Ludwigshafen, Germany. All lab work was done at the University Hospital, Heidelberg. METHODS: Spinal cord injury was classified according to the American Spinal Injury Association (ASIA) impairment scale (AIS) in 23 patients. TNF-α and IL-1ß levels were measured upon arrival at the hospital, after 4 h, 9 h and 12 h, on days 1 and 3 and at the end of weeks 1, 2, 4, 8 and 12. RESULTS: Temporal changes in TNF-α and IL-1ß in SCI patients were seen. Patients with AIS improvement (Group 1) had significantly lower TNF-α levels at 9 h compared with patients without AIS improvement (Group 2; P<0.01). The course of IL-1ß fluctuated greatly between 4 h and week 1 in the groups; however, between 2 and 12 weeks post trauma, there was an overall decline in both groups. CONCLUSION: Measuring serum levels of TNF-α and IL-1ß over time could be useful in tracking the course of SCI. Our data show differences in measured cytokines over a 12-week period for SCI patients with and without neurological improvement.