The Induction of Bone Formation and the Osteogenic Proteins of the Transforming Growth Factor-β Supergene Family
Ugo Ripamonti in The Geometric Induction of Bone Formation, 2020
Bone as a skeletal armour developed as a biological and physical defence against the predaceous habits of the eurypterids, largely feeding on the early vertebrate “bony fishes” at the evolutionary beginning of the vertebrates. It seems likely that the eurypterids’ aggressive feeding on the evolutionary beginning of the vertebrates “was primarily responsible for the development of the vertebrate bony armour”. Columnar condensations of chondroblastic cells are to be found in the pleiotropic uniqueness of the cartilaginous growth plate, a fundamental compartmentalized biological system of growth that masterminds the tri-dimensional growth of the mammalian axial skeleton that forms through endochondral osteogenesis via the cartilage anlage. Primarily, membranous osteogenesis originates after the induction of mesenchymal condensations populated by contiguous osteoblasts that later continuously secrete bone matrix as yet to be mineralized, or osteoid, around invading and supporting central blood vessels. In the bone matrix, molecular signals are in solution, interacting with the insoluble signal of the extracellular matrix.
Surface Modification Techniques
S Santhosh Kumar, Somashekhar S. Hiremath in Role of Surface Modification on Bacterial Adhesion of Bio-Implant Materials, 2020
This chapter describes objectives of the surface modification techniques and different classifications of the surface modification methods to alter the surface properties of the implants. The surface properties and topography have more influence, and to achieve these properties, researchers are continually trying to develop the various surface modification techniques. The main objective of the surface modification of biomaterials is to improve interfacial properties such as wettability, adsorption of proteins, and ligands and to improve roughness that will enhance the biomaterials' effectiveness. The typical objective of mechanical modification is to obtain specific surface topographies and roughness, remove surface contamination, and improve adhesion in subsequent bonding steps. Physicochemical characteristics such as surface free energy, surface charge, chemical composition, and surface wettability are fundamental parameters that influence osteoblast attachment.
Bone structure
John C Stevenson, Michael S Marsh in An Atlas of Osteoporosis, 2007
Bone provides the strength and rigidity of the skeleton as well as acting as a reservoir of calcium and other mineral salts. It is a highly vascular, mineralized connective tissue of cells in a fibrous organic matrix permeated by inorganic bone salts. Cortical bone is always found on the outside of bones and surrounds the trabecular bone. Approximately 80% of the skeleton is cortical bone. Cortical bone is porous, but the ratio of solid tissue to space is considerably higher than for trabecular bone. Trabecular bone is found in the middle of bones such as the vertebrae, pelvis, and other flat bones, and at the ends of the long bones. There are three main types of bone cells: osteoblasts, osteoclasts, and osteocytes. Normal adult bone is termed lamellar bone. Each lamella is a thin plate 5–7 µm thick and made up of bone matrix consisting of protein fibers impregnated with bone salts.
Possible roles of insulin signaling in osteoblasts
Published in Endocrine Research, 2014
Sakarat N. Pramojanee, Mattabhorn Phimphilai, Nipon Chattipakorn, Siriporn C. Chattipakorn
Insulin and its downstream signaling pathway are indispensable for postnatal bone growth and turnover by having influence on both osteoblast and osteoclast development. Insulin signaling regulates both bone formation by osteoblasts and bone resorption by osteoclasts; however, the regulation occurs mainly through the insulin signaling pathway within osteoblasts. An impairment of osteoblastic insulin signaling leads to an impaired bone quality by affecting osteoblast proliferation, differentiation and survival. The insulin signaling pathway and MAPK and PI3K/Akt pathways play pivotal roles in the differentiation, function and survival of bone cells. Current evidence suggests that osteoblastic insulin signaling not only modulates bone growth and turnover but is also required for energy metabolism. Several mice models with impaired insulin signaling exhibited both bone and metabolic phenotypes, including symptoms of low bone mass, obesity, glucose intolerance and insulin resistance. In this review, we discuss the key findings that suggest a pivotal role of osteoblastic insulin signaling in both bone and energy metabolism.
Leptin promotes ossification through multiple ways of bone metabolism in osteoblast: a pilot study
Published in Gynecological Endocrinology, 2013
Jing Zhang, Tingting Li, Liangzhi Xu, Wenjuan Li, Meng Cheng, Jing Zhuang, Yan Chen, Wenming Xu
Leptin may be a potential option in preventing osteoporosis for menopausal women. The objective of this study is to explore the molecular mechanism of leptin on bone metabolism in osteoblast. Primary osteoblasts were isolated from parietal bone of adult female rats. mRNA level of OB-Rb in osteoblasts was inhibited by siRNA to block leptin signal transmission. The whole genome expression was tested by using gene chip to preliminarily explore the molecular mechanism of leptin in regulating osteoblast activity. The optimal concentration of siRNA was 25 nM, resulting in a maximal inhibition of OB-Rb mRNA. Ossification (p
Acidic pH environments increase the expression of cathepsin B in osteoblasts: The significance of ER stress in bone physiology
Published in Immunopharmacology and Immunotoxicology, 2009
Song-Hee Han, Soo-Wan Chae, Je-Yong Choi, Eun-Cheol Kim, Han-Jung Chae, Hyung-Ryong Kim
Hypoxia, inflammation, and acidity occur after bone fracture. To simplify the fracture model, we tested the effects of acidity in osteoblasts. We tested three osteoblast cell lines, MG63, MC3T3E1, and HOS cells, with MG63 cells showing much higher sensitivity to acidic pH. In physiologically acidic surroundings, pH 7.2, the endoplasmic reticulum stress response was measured through the expression of unfolded protein response proteins. Acidic surroundings time-dependently increased IL-6 secretion. Cathepsin B, a marker of the inflammation and angiogenic processes that occur after bone fracture, also increased. Thus, acidity can cause ER stress, increase IL-6, and increases cathepsin B expression in osteoblasts.