Angiogenic potential of human mesenchymal stromal cell and circulating mononuclear cell cocultures is reflected in the expression profiles of proangiogenic factors leading to endothelial cell and pericyte differentiation.

Endothelial progenitors found among the peripheral blood (PB) mononuclear cells (MNCs) are interesting cells for their angiogenic properties. Mesenchymal stromal cells (MSCs) in turn can produce proangiogenic factors as well as differentiate into mural pericytes, making MSCs and MNCs an attractive coculture setup for regenerative medicine. In this study, human bone marrow-derived MSCs and PB-derived MNCs were cocultured in basal or osteoblastic medium without exogenously supplied growth factors to demonstrate endothelial cell, pericyte and osteoblastic differentiation.

Transient 100 nM dexamethasone treatment reduces inter- and intraindividual variations in osteoblastic differentiation of bone marrow-derived human mesenchymal stem cells.

The development of in vitro culturing techniques for osteoblastic differentiation of human mesenchymal stem cells (hMSC) is important for cell biology research and the development of tissue-engineering applications. Dexamethasone (Dex) is a commonly used supplement, but the optimal use of Dex treatment is still unclear. By adjusting the timing of Dex supplementation, the negative effects of long-term Dex treatment could be overcome.

Circulating plastic adherent mesenchymal stem cells in aged hip fracture patients.

We examined the presence of circulating plastic adherent multipotent mesenchymal stem cells (MSCs) in fracture patients. Three patient groups (n = 10-18) were evaluated, including elderly females with a femoral neck fracture treated with cemented hemiarthroplasty, an age- and sex-matched group with hip osteoarthritis (OA) treated with cemented total hip arthroplasty (THA), and younger adults with surgically treated lower extremity fractures. The presence of circulating MSCs pre- and postoperatively was compared to bone marrow (BM) MSCs from the same subjects.

Microdamage detection and repair in bone: fracture mechanics, histology, cell biology.

Bone is an elementary component in the human skeleton. It protects vital organs, regulates calcium levels and allows mobility. As a result of daily activities, bones are cyclically strained causing microdamage.

Expression of macrophage inhibitory cytokine-1 in prostate cancer bone metastases induces osteoclast activation and weight loss.

Background: Macrophage inhibitory cytokine-1 (MIC-1) belongs to the bone morphogenic protein/transforming growth factor-beta (BMP/TGF-beta) superfamily. Serum MIC-1 concentrations are elevated in patients with advanced prostate cancer. The effects of MIC-1 on prostate cancer bone metastases are unknown.

Differentiation of osteoblasts and osteocytes from mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are multipotent cells that arise from the mesenchyme during development. They reside in the bone marrow close to hematopoietic stem cell niches allowing them to maintain bone marrow homeostasis and to regulate the maturation of both hematopoietic and non-hematopoietic cells. MSCs possess an extensive potential to proliferate and differentiate e.

Estrogen and testosterone use different cellular pathways to inhibit osteoclastogenesis and bone resorption.

Unlabelled: Using human peripheral blood CD14(+) osteoclast precursors, we show that testosterone directly inhibits osteoclast formation and bone resorption at physiological concentrations. Instead, estrogen has no direct effects, whereas its action seems to be mediated through osteoblasts by producing osteoprotegerin. Both estrogen and testosterone acts through their cognate receptors.

Isolated primary osteocytes express functional gap junctions in vitro.

The osteocyte is the most abundant cell type in bone and is embedded in mineralized bone matrix. Osteocytes are still poorly characterized because of their location and the lack of primary osteocyte isolation methods. Data on the cell biology of osteocytes is especially limited.

Death of osteocytes turns off the inhibition of osteoclasts and triggers local bone resorption.

Osteocytes have been suggested to play a role in the regulation of bone resorption, although their effect on bone turnover has remained controversial. In order to study this open question, we developed an organ culture system based on isolated rat calvaria, where the osteocyte viability and its effect on osteoclastic bone resorption can be monitored. Our results suggest that osteocytes are constitutively negative regulators of osteoclastic activity.

Conditioned medium from osteocytes stimulates the proliferation of bone marrow mesenchymal stem cells and their differentiation into osteoblasts.

Osteocytes are the most abundant cells in bone and there is increasing evidence that they control bone remodeling via direct cell-to-cell contacts and by soluble factors. In the present study, we have used the MLO-Y4 cell line to study the effect of osteocytes on the proliferation, differentiation and bone-forming capacity of bone marrow mesenchymal stem cells (MSC). Conditioned media (CM) from osteocytic MLO-Y4 and osteoblastic MC3T3-E1 cell lines were collected and added on mouse bone marrow cultures, in which MSC were induced to osteoblasts.

Release of intact and fragmented osteocalcin molecules from bone matrix during bone resorption in vitro.

Osteocalcin detected from serum samples is considered a specific marker of osteoblast activity and bone formation rate. However, osteocalcin embedded in bone matrix must also be released during bone resorption. To understand the contribution of each type of bone cell in circulating osteocalcin levels, we used immunoassays detecting different molecular forms of osteocalcin to monitor bone resorption in vitro.

Osteocytes inhibit osteoclastic bone resorption through transforming growth factor-beta: enhancement by estrogen.

Osteocytes are the most abundant cells in bone and distributed throughout the bone matrix. They are connected to the each other and to the cells on the bone surface. Thus, they may also secrete some regulatory factors controlling bone remodeling.