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Bionanocomposites
Published in Satya Eswari Jujjavarapu, Krishna Mohan Poluri, Green Polymeric Nanocomposites, 2020
Archita Gupta, Padmini Padmanabhan, Sneha Singh
Remodeling mainly comprises three steps: initiation of cell resorption by osteoclasts during hypocalcemia; then osteoblasts come into play by forming a new matrix over the resorbed bone; finally, when the osteogenesis is completed, osteoblasts differentiate into osteocytes and maintain the bone resorption and formation in a systemic manner. Any imbalance in these processes leads to bone disease, such as osteoporosis. The process of remodeling is mainly based on two phenomena: quantum and coupling. According to the quantum concept, the variation in bone density is mainly due to an imbalance between bone resorption and formation by osteoclasts and osteoblasts, respectively (Frost 1963 and Parfitt 1979). BRU is the main constituent of the bone at different developmental stages. Arrangement of these units and minerals define the turnover of bone matrix and become the basis for change in bone mass observed during aging and metabolic bone diseases. In this concept, first the osteoclastic precursors are differentiated to osteoclasts, and bone resorption starts. The growth factors, proteins, and cytokines are involved in activating osteoclast for resorption. Osteoclasts express tartrate-resistant acid phosphatase (TRAP) which leads to a decrease in pH due to hydrogen ion release by the carbonic anhydrase system. Acidic pH helps in dissolving HA crystals and organic components of the matrix.
Osteoimmunomodulation with Biomaterials
Published in Nihal Engin Vrana, Biomaterials and Immune Response, 2018
Bengü Aktaş, Bora Garipcan, Zehra Betül Ahi, Kadriye Tuzlakoğlu, Emre Ergene, Pınar Yılgör Huri
Osteoclasts stem from the hematopoietic stem cells (HSCs) that reside within the bone marrow. HSCs form mononuclear cells and eventually osteoclasts (Figure 8.2) [8]. It is worth noting that osteoclasts share the same maturation pathway as innate immune cells and macrophages and are considered to be resident macrophages specific to the bone microenvironment. In the bone microenvironment, localised multiple systemic hormones and cytokines are produced that promote osteoclast differentiation and function. These include receptor activator of nuclear factor κβ ligand (RANKL) and macrophage colony-stimulating factor (M-CSF) [9,10]. These membrane-bound proteins are produced by neighbouring stromal cells and osteoblasts. Therefore, osteoclastogenesis is regulated by osteoclast precursors together with osteoblasts, osteocytes and immune cells [9,10].
In Situ Nanotechnology-Derived Sensors for Ensuring Implant Success
Published in Šeila Selimovic, Nanopatterning and Nanoscale Devices for Biological Applications, 2017
Sirinrath Sirivisoot, Thomas J. Webster
Bone resorption and remodeling involve the secretion of hydrochloric acid (HCl) by osteoclasts [31]. Osteoclasts dissolve bone mineral by isolating a region of the matrix and then secreting HCl and proteinases on the bone surface, resulting in the bone acting as a reservoir of Ca2+,PO43−, and OH− [32]. This may be the reason why HCl is routinely used in laboratories to dissolve Ca minerals deposited on osteoblast-seeded scaffolds in vitro as a supernatant for further use in a Ca deposition assay. Thus, after dissolving with 0.6 N HCl, it is likely that Ca2+,PO43−, and OH− are contained in the solution of osteoblast extracellular components.
The opportunity of using alloplastic bone augmentation materials in the maxillofacial region– Literature review
Published in Particulate Science and Technology, 2019
Simion Bran, Grigore Baciut, Mihaela Baciut, Ileana Mitre, Florin Onisor, Mihaela Hedesiu, Avram Manea
Osteoclasts are multinucleated cells that play the main role in bone resorption. They are only cells that destroy and resorb bone. Abnormal increase in osteoclast function leads to bone diseases such as osteoporosis (where resorption exceeds formation decreasing bone density and increasing fracture rate). In other pathologic conditions (e.g., bone metastases and inflammatory arthritis) abnormal osteoclast activity results in periarticular erosions and painful osteolytic lesions (Hellstein et al. 2011). This imbalance between resorption and formation of the bone is frequently treated with drugs called bisphosphonates which decrease osteoclast activity. Although their benefits considerably outweigh the risks, one side effect must be noted: the risk of BRONJ (Bisphosphonate-Related Osteonecrosis of the Jaw). This is why, the practitioner that performs any type of bone surgery must be aware of present bisphosphonate therapy and even distant history of such treatment (Charles and Aliprantis 2014).
Chitosan oligosaccharide promotes osteoclast formation by stimulating the activation of MAPK and AKT signaling pathways
Published in Journal of Biomaterials Science, Polymer Edition, 2018
Bing-Li Bai, Zhong-Jie Xie, She-Ji Weng, Zong-Yi Wu, Hang Li, Zhou-Shan Tao, Viraj Boodhun, De-Yi Yan, Zi-Jian Shen, Jia-Hao Tang, Lei Yang
For primary cell culture, BMMs were isolated from the whole bone marrow of male 6-week-old C57BL/6 mice as described previously [15]. That is to say, cells were isolated from the femoral and tibial bone marrow. Then, BMMs were cultured in α-MEM supplemented with 10% FBS, 30 ng/mL M-CSF and 1% penicillin/streptomycin in an incubator with 5% CO2 at 37 °C until they reached 90% confluence. The BMMs were subsequently seeded in a 96-well plate at a density of 8x103 cells/well in complete α-MEM supplemented with 30 ng/ml M-CSF, 50 ng/ml RANKL and different concentrations of COS (0, 5, 50 or 500 ng/ml). Culture media were replaced every 2 days until mature osteoclasts were formed. Afterward, the cells were washed twice with PBS, fixed in 4% paraformaldehyde (PFA) for 20 min, and subjected to tartrate-resistant acid phosphatase (TRAP) staining. TRAP staining is applied for identifying osteoclasts differentiation. TRAP-positive cells with > 3 nuclei were counted under a microscope.
Effect of locally administered novel biodegradable chitosan based risedronate/zinc-hydroxyapatite intra-pocket dental film on alveolar bone density in rat model of periodontitis
Published in Journal of Biomaterials Science, Polymer Edition, 2018
Deepak Kumar Khajuria, Saadath Fathima Zahra, Rema Razdan
The most common cause of tooth loss in adults is periodontitis wherein there is gingival bleeding, loss of connective tissue connection, development of periodontal pocket, and alveolar bone loss [1]. Activated osteoclast cells causes bone resorption in periodontitis. The osteoclast cells are activated by several factors, including cytokines which promotes an increase of RANKL (receptor activator of nuclear factor k-B ligand) in the osteoblast cells favoring RANKL–RANK receptor linkage causing osteoclastogenesis [2]. Alveolar bone loss is a hallmark of periodontitis progression. Thus, osteogenic and/or antiresorptive medication is generally considered in the therapy of periodontitis.