TY  - JOUR
A1  - Schmid, Franziska
A1  - Kleinhans, Claudia
A1  - Schmid, Freia
A1  - Kluger, Petra
T1  - Osteoclast formation within a Human co-culture system on bone material as an in vitro model for bone remodeling processes
JF  - Journal of functional morphology and kinesiology : JFMK
N2  - Bone remodeling can be mimicked in vitro by co-culture models. Based on bone cells, such co-cultures help to study synergistic morphological changes and the impact of materials and applied substances. Hence, we examined the formation of osteoclasts on bovine bone materials to prove the bone resorption functionality of the osteoclasts in three different co-culture set-ups using human monocytes (hMCs) and (I) human mesenchymal stem cells (hMSCs), (II) osteogenic differentiated hMSCs (hOBs), and (III) hOBs in addition of soluble monocyte-colony stimulating factor (M CSF) and cytokine receptor activator of NFkB ligand (RANKL).We detected osteoclast-specific actin morphology, as well as the expression of cathepsin K and CD51/61 in single cells in set-up II and in numerous cells in set-up III. Resorption pits on bone material as characteristic proof of functional osteoclasts were not found in set-up I and II, but we detected such resorption pits in set–up III. We conclude in co culture models without M-CSF and RANKL that monocytes can differentiate into osteoclasts that show the characteristic actin structures and protein expression. However, to receive functional bone resorbing osteoclasts in vitro, the addition of M-CSF and RANKL is needed. Moreover, we suggest the use of bone or bone-like materials for future studies evaluating osteoclastogenesis.
KW  - bone resorption
KW  - human monocytes
KW  - osteoclasts
KW  - osteoclastogenesis
KW  - bone remodeling
KW  - co-culture model
KW  - in vitro test system
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bsz:rt2-opus4-22329
SN  - 2411-5142
VL  - 3
IS  - 1, 17
SP  - 1
EP  - 16
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Kleinhans, Claudia
A1  - Schmid, Freia
A1  - Schmid, Franziska
A1  - Kluger, Petra
T1  - Comparison of osteoclastogenesis and resorption activity of human osteoclasts on tissue culture polystyrene and on natural extracellular bone matrix in 2D and 3D
JF  - Journal of biotechnology
N2  - Bone homeostasis is maintained by osteoblasts (bone formation) and osteoclasts (bone resorption). While there have been numerous studies investigating mesenchymal stem cells and their potential to differentiate into osteoblasts as well as their interaction with different bone substitute materials, there is only limited knowledge concerning in vitro generated osteoclasts. Due to the increasing development of degradable bone-grafting materials and the need of sophisticated in vitro test methods, it is essential to gain deeper insight into the process of osteoclastogenesis and the resorption functionality of human osteoclasts. Therefore, we focused on the comparison of osteoclastogenesis and resorption activity on tissue culture polystyrene (TCPS) and bovine extracellular bone matrices (BMs). Cortical bone slices were used as two-dimensional (2D) substrates, whereas a thermally treated cancellous bone matrix was used for three-dimensional (3D) experiments. We isolated primary human monocytes and induced osteoclastogenesis by medium supplementation. Subsequently, the expression of the vitronectin receptor (αVβ3) and cathepsin K as well as the characteristic actin formation on TCPS and the two BMs were examined. The cell area of human osteoclasts was analyzed on TCPS and on BMs, whereas significantly larger osteoclasts could be detected on BMs. Additionally, we compared the diameter of the sealing zones with the measured diameter of the resorption pits on the BMs and revealed similar diameters of the sealing zones and the resorption pits. We conclude that using TCPS as culture substrate does not affect the expression of osteoclast-specific markers. The analysis of resorption activity can successfully be conducted on cortical as well as on cancellous bone matrices. For new in vitro test systems concerning bone resorption, we suggest the establishment of a 2D assay for high throughput screening of new degradable bone substitute materials with osteoclasts.
KW  - osteoclastogenesis
KW  - human monocytes
KW  - osteoclasts
KW  - cell–material interactions
KW  - bone resorption
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bsz:rt2-opus4-5287
SN  - 0168-1656
VL  - 205
SP  - 101
EP  - 110
PB  - Elsevier
CY  - Amsterdam
ER  -