Effects of mechanical stress and scaffold material on osteogenesis and chondrogenesis
ABSTRACT The present study was designed to investigate how mouse bone marrow stromal ST2 cells and rat limb mesenchymal stem cells respond to mechanical stress. Mechanical stress loading culture devices originally developed or commercially available were used to induce quantitative strain to these cells. Differentiation of ST2, estimated by alkaline phosphatase (ALP), was shown to be affected by the amount of the strain. Chondrogenic cell differentiation was enhanced by stretch stimulation through phosphplylation of extracellular-signaling regulated kinases (ERKs). In this study, the effect of synthetic scaffold octacalcium phosphate (OCP) was also determined. OCP implantation enhanced bone regeneration. The results suggest that the differentiation of these skeletal tissue forming cells is under control of the mechanical stresses through the signaling cascade. It is likely that the scaffold plays a role of site scaffolding the cells to assist differentiation.
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ABSTRACT: Cell function to form bone would be influenced by local environment, such as mechanical stress and tissue fluid constituents over intracellular signal transduction to macroscopic order. For example, osteoblasts and osteocytes respond to mechanical stimuli by changing their metabolism, proliferation, and differentiation. Our recent study showed that the elevated extracellular calcium stimulated secretion of osteogenic bone morphogenetic protein-2 by a macrophage cell line. The macrophage-like cells appeared near bioresorbable bone substitute such as octacalcium phosphate (OCP). OCP has been identified an intermediate to various biological apatite crystals. If OCP were implanted into the living animals, bio-resorbable OCP would modify local environment during bone regeneration by irreversibly transforming to bone-like apatite, which accompanied with calcium uptake and phosphate release. Recently, we have developed a synthetic bone regenerative material constructed of synthetic OCP and porcine atelocollagen (OCP/Collagen). OCP/Collagen enhanced bone regeneration more than OCP per se. OCP/Collagen constructed three-dimensional scaffold for bone regeneration01/2006;
Conference Paper: A New Configuration Device for Mechanical Stress Culture[Show abstract] [Hide abstract]
ABSTRACT: The musculoskeletal system is a unique combination of soft and hard tissues in the body, consisted of bone, cartilage, muscle and tendon. These skeletal tissue formation are in essence organized by the tissue specific cells, including osteoblasts, osteocytes, chondrocytes, myocytes and fibroblasts. Mechanical stress has a variety of effects on the structure and function of their cells. However, little is known about the effect of mechanical stress on cell differentiation regarding the quality and quantity of the stress and the timing applied. In the present study, we developed a culture device that enables to load the mechanical stress quantitatively with ease to evaluate proliferation and differentiation of cellsMicro-NanoMechatronics and Human Science, 2006 International Symposium on; 12/2006
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ABSTRACT: Musculoskeletal system regulates and supports mammalian body movement by generating force and by resisting to the force exerted on the body. Skeletal tissues, bone, cartilage, muscle and tendon are mechano-responsive tissues consisted of osteoblasts, chondrocytes, myocytes and fibroblasts and their specific extracellular matrices (ECMs). Mechanical stress presents a variety of effects on the metabolism and differentiation state of these cells. During bone growth, growth plate cartilage plays a pivotal role in growth in length of bone by providing templates consisted of cartilage specific ECM, which is replaced by bone. Chondrocytes, form cartilage in synovial joints and growth plates, respond to compressive force by activating their metabolism and progressing differentiation, while tensile stimulation inhibits their differentiation. Mechanical stimulation is translated into intracellular signaling, which regulates the differentiation state and metabolism of chondrocytes. To analyze the mechanobiological response, we have been developing mechanical stress culture device. Here, we present the mechanical stress culture device and mechnobiological response of differentiating chondrocytes to stretch stimulation.Nano/Micro Engineered and Molecular Systems, 2007. NEMS '07. 2nd IEEE International Conference on; 02/2007