Polypeptide factors regulating osteogenesis and bone marrow repair

Abstract

Osteogenic growth polypeptides regulate bone cell function in vitro and may act in vivo in an autocrine, paracrine, or endocrine manner. Several of these polypeptides are present in the blood in an inactive form. During postablation bone marrow regeneration these factors may be activated, released from the blood clot, and together with locally produced polypeptides mediate the initial intramedullary/systemic osteogenic phase of this process. Then, the same and/or other polypeptides expressed by stromal cells have the potential to promote the second phase of regeneration that consists of osteoclastogenesis, resorption of the transient intramedullary bone, and hemopoiesis. This may be an indirect influence since these polypeptides can regulate the stromal cell expression of some of the hemopoietic factors. Clinically, the osteogenic growth polypeptides that regulate osteogenesis and hemopoiesis have a potential role in osteoporosis therapy, implant bone surgery, and bone marrow transplantation.

Subcutaneous tissue response and osteogenic performance of calcium phosphate nanoparticle-enriched hydrogels in the tibial medullary cavity of guinea pigs

“…After marrow removal, the blood clot fills the diaphyseal medullary cavity and releases several osteogenic growth polypeptides, such as insulin-like growth factor (IGF-I), and osteogenic growth peptide (OGP), which mediate the replacement with primary trabecular bone (the so-called initial intramedullary osteogenic phase) [33,34]. The formation of bone progresses centripetally, i.e.…”

Endothelial Nitric Oxide Synthase Gene-Deficient Mice Demonstrate Marked Retardation in Postnatal Bone Formation, Reduced Bone Volume, and Defects in Osteoblast Maturation and Activity

“…These include the spatially and temporally co-ordinated proliferation, recruitment, and differentiation of osteoblasts at resorption sites, the subsequent synthesis and maturation of bone matrix proteins and also by the overall life span of the osteoblast. [1][2][3] Our data demonstrate that NO-dependent signaling via eNOS is important in regulating several aspects of osteoblast biology including growth, differentiation, recruitment, and extracellular matrix synthesis. Although not specifically addressed in the present study the effects of eNOS gene deficiency will probably also impact on other important aspects of osteoblast biology.…”

“…Bone is a vital dynamic connective tissue that has evolved to maintain a balance between its two major functions: provision of mechanical integrity for locomotion and modulation and control of mineral homeostasis. 1 Mineralized bone is continuously resorbed by osteoclasts and new bone is formed by osteoblasts. This process, known as bone remodeling, is highly regulated with maintenance of normal integrity and structure.…”

A Validated Method for Titanium Implant Anchorage Analysis using MicroCT and Biomechanical Testing

“…The %OI increases progressively with time after implantation, apparently consequent to induction of osteoblast activity by the titanium implant [19]. The initial elevation in PIB parameters during the first couple of weeks after implantation is attributable to the osteogenic bone marrow reaction to the injury associated with implant insertion [20]. This reaction consists of de novo primary bone formation in the inter-trabecular spaces and increased bone formation on the surfaces of pre-existing trabeculae.…”

“…This reaction consists of de novo primary bone formation in the inter-trabecular spaces and increased bone formation on the surfaces of pre-existing trabeculae. The decrease in these parameters that follows results from remodeling of the reactive bone [20].…”