scholarly journals Biology of Bone Tissue: Structure, Function, and Factors That Influence Bone Cells

2015 ◽  
Vol 2015 ◽  
pp. 1-17 ◽  
Author(s):  
Rinaldo Florencio-Silva ◽  
Gisela Rodrigues da Silva Sasso ◽  
Estela Sasso-Cerri ◽  
Manuel Jesus Simões ◽  
Paulo Sérgio Cerri

Bone tissue is continuously remodeled through the concerted actions of bone cells, which include bone resorption by osteoclasts and bone formation by osteoblasts, whereas osteocytes act as mechanosensors and orchestrators of the bone remodeling process. This process is under the control of local (e.g., growth factors and cytokines) and systemic (e.g., calcitonin and estrogens) factors that all together contribute for bone homeostasis. An imbalance between bone resorption and formation can result in bone diseases including osteoporosis. Recently, it has been recognized that, during bone remodeling, there are an intricate communication among bone cells. For instance, the coupling from bone resorption to bone formation is achieved by interaction between osteoclasts and osteoblasts. Moreover, osteocytes produce factors that influence osteoblast and osteoclast activities, whereas osteocyte apoptosis is followed by osteoclastic bone resorption. The increasing knowledge about the structure and functions of bone cells contributed to a better understanding of bone biology. It has been suggested that there is a complex communication between bone cells and other organs, indicating the dynamic nature of bone tissue. In this review, we discuss the current data about the structure and functions of bone cells and the factors that influence bone remodeling.

2020 ◽  
Vol 27 (6) ◽  
pp. 838-853 ◽  
Author(s):  
Madalina Icriverzi ◽  
Valentina Dinca ◽  
Magdalena Moisei ◽  
Robert W. Evans ◽  
Mihaela Trif ◽  
...  

: Among the multiple properties exhibited by lactoferrin (Lf), its involvement in bone regeneration processes is of great interest at the present time. A series of in vitro and in vivo studies have revealed the ability of Lf to promote survival, proliferation and differentiation of osteoblast cells and to inhibit bone resorption mediated by osteoclasts. Although the mechanism underlying the action of Lf in bone cells is still not fully elucidated, it has been shown that its mode of action leading to the survival of osteoblasts is complemented by its mitogenic effect. Activation of several signalling pathways and gene expression, in an LRPdependent or independent manner, has been identified. Unlike the effects on osteoblasts, the action on osteoclasts is different, with Lf leading to a total arrest of osteoclastogenesis. : Due to the positive effect of Lf on osteoblasts, the potential use of Lf alone or in combination with different biologically active compounds in bone tissue regeneration and the treatment of bone diseases is of great interest. Since the bioavailability of Lf in vivo is poor, a nanotechnology- based strategy to improve the biological properties of Lf was developed. The investigated formulations include incorporation of Lf into collagen membranes, gelatin hydrogel, liposomes, loading onto nanofibers, porous microspheres, or coating onto silica/titan based implants. Lf has also been coupled with other biologically active compounds such as biomimetic hydroxyapatite, in order to improve the efficacy of biomaterials used in the regulation of bone homeostasis. : This review aims to provide an up-to-date review of research on the involvement of Lf in bone growth and healing and on its use as a potential therapeutic factor in bone tissue regeneration.


2021 ◽  
Vol 22 (15) ◽  
pp. 8182
Author(s):  
Yongguang Gao ◽  
Suryaji Patil ◽  
Jingxian Jia

Osteoporosis is one of the major bone disorders that affects both women and men, and causes bone deterioration and bone strength. Bone remodeling maintains bone mass and mineral homeostasis through the balanced action of osteoblasts and osteoclasts, which are responsible for bone formation and bone resorption, respectively. The imbalance in bone remodeling is known to be the main cause of osteoporosis. The imbalance can be the result of the action of various molecules produced by one bone cell that acts on other bone cells and influence cell activity. The understanding of the effect of these molecules on bone can help identify new targets and therapeutics to prevent and treat bone disorders. In this article, we have focused on molecules that are produced by osteoblasts, osteocytes, and osteoclasts and their mechanism of action on these cells. We have also summarized the different pharmacological osteoporosis treatments that target different molecular aspects of these bone cells to minimize osteoporosis.


2020 ◽  
Vol 27 (7) ◽  
pp. 1151-1169 ◽  
Author(s):  
Yi Zhang ◽  
Guojing Luo ◽  
Xijie Yu

Background: Intercellular crosstalk among osteoblast, osteoclast, osteocyte and chondrocyte is involved in the precise control of bone homeostasis. Disruption of this cellular and molecular signaling would lead to metabolic bone diseases such as osteoporosis. Currently a number of anti-osteoporosis interventions are restricted by side effects, complications and long-term intolerance. This review aims to summarize the bone cellular communication involved in bone remodeling and its usage to develop new drugs for osteoporosis. Methods: We searched PubMed for publications from 1 January 1980 to 1 January 2018 to identify relevant and latest literatures, evaluation and prospect of osteoporosis medication were summarized. Detailed search terms were ‘osteoporosis’, ‘osteocyte’, ‘osteoblast’, ‘osteoclast’, ‘bone remodeling’, ‘chondrocyte’, ‘osteoporosis treatment’, ‘osteoporosis therapy’, ‘bisphosphonates’, ‘denosumab’, ‘Selective Estrogen Receptor Modulator (SERM)’, ‘PTH’, ‘romosozumab’, ‘dkk-1 antagonist’, ‘strontium ranelate’. Results: A total of 170 papers were included in the review. About 80 papers described bone cell interactions involved in bone remodeling. The remaining papers were focused on the novel advanced and new horizons in osteoporosis therapies. Conclusion: There exists a complex signal network among bone cells involved in bone remodeling. The disorder of cell-cell communications may be the underlying mechanism of osteoporosis. Current anti-osteoporosis therapies are effective but accompanied by certain drawbacks simultaneously. Restoring the abnormal signal network and individualized therapy are critical for ideal drug development.


2020 ◽  
Vol 10 (2) ◽  
pp. 240-250
Author(s):  
Zhenlv Zou ◽  
Gang Mei ◽  
Liying Tang ◽  
Yafei Xu ◽  
Jun Liu ◽  
...  

Bone fracture healing is a complex process involving a cascade of cellular and molecular events that are orchestrated by a variety of factors, including neuropeptides and their receptors. However, the roles of neuropeptides and their receptors in the fracture healing process are controversial. We monitored the expression and distribution of the neuropeptides, substance P (SP) and neuropeptide Y (NPY) and their receptors, neurokinin 1 receptor (NK1) and neuropeptide Y1 receptor (NPY1R), in rats undergoing fracture healing. Total RNA was extracted using Fe3O4 and was retrieved into DNA using the MagBeads Total RNA Extraction Kit. The expression levels of SP, NK1, and NPY at each time point in the healing bone tissue were found to be higher than the levels in normal bone tissue. Their location and expression levels correlated with the healing process. In the callus formation stage, the expression levels of SP, NK1, and NPY were found to be increased in the matrix of the cartilage, in chondrocytes, and in the subperiosteal region. At the bone remodeling stage, they were located in the periosteum, new bone tissue, and perivascular regions, and their expression levels gradually reduced. Therefore, we conclude that SP was involved in callus formation and bone resorption at different physiological concentrations. At some concentrations, SP positively regulated new bone formation via NK1. At other concentrations, the SP-NK1 interaction promoted bone resorption. Very low expression levels of NPY1R were observed at the early healing stage, but they increased at the middle stage and then decreased at the late stage. This indicated that NPY was involved in bone formation through NPY1R-unrelated mechanisms. NPY1R was more involved at the later stage of bone remodeling, according to its expression levels. NPY1R contributed to callus formation and remodeling.


2020 ◽  
Vol 9 (11) ◽  
pp. 3439
Author(s):  
Stéphanie Fabre ◽  
Thomas Funck-Brentano ◽  
Martine Cohen-Solal

The Wnt pathway is a key element of bone remodeling; its activation stimulates bone formation and inhibits bone resorption. The discovery of sclerostin, a natural antagonist of the Wnt pathway, promoted the development of romosozumab, a human monoclonal antibody directed against sclerostin, as well as other anti-sclerostin antibodies. Phase 3 studies have shown the efficacy of romosozumab in the prevention of fractures in postmenopausal women, against placebo but also against alendronate or teriparatide and this treatment also allows bone mineral density (BMD) increase in men. Romosozumab induces the uncoupling of bone remodeling, leading to both an increase in bone formation and a decrease in bone resorption during the first months of treatment. The effect is attenuated over time and reversible when stopped but transition with anti-resorbing agents allows the maintenance or reinforcement of BMD improvements. Some concerns were raised about cardiovascular events. Therefore, romosozumab was recently approved in several countries for the treatment of severe osteoporosis in postmenopausal women with high fracture risk and without a history of heart attack, myocardial infarction or stroke. This review aims to outline the role of sclerostin, the efficacy and safety of anti-sclerostin therapies and in particular romosozumab and their place in therapeutic strategies against osteoporosis or other bone diseases.


2017 ◽  
Vol 6 ◽  
pp. 28-35
Author(s):  
Galina Prots ◽  
Mykola Rozhko ◽  
Vasyl Pjuryk ◽  
Irina Prots

Aim: To Improve the treatment of patients with partial edentia and chronic generalized periodontitis by including dental implantation to the complex of therapeutic measures. Materials and methods: There have been presented the results of 240 patients with varying severity degrees of generalized periodontitis who underwent surgery on periodontal tissues with dental implantation. The research was conducted at the OCH of Ivano-Frankivsk 2007–2017.To improve the efficiency for dental implants and periodontal surgical intervention is necessary to determine the quality of bone remodeling, identifying markers of bone tissue metabolism. Results: It was established that in 40,81 % patients the results of research showed markers of bone remodeling indicating a high rate of bone formation (25,12±2,23 ng / ml) and a slight increase in rate of resorption marker, which results in low rates of bone resorption (8,54±1,23 nmol/L). These patients were not prescribed with osteotropic drugs. 50,83 % of patients with osteopenia were noticed to manifest the formation of bone possible raise of bone resorption (10.82±1.34n/mole), which was the indication for antiresorptive medication prescription. In 8,36 % of patients with osteoporosis was observed inhibition of bone formation processes (18,05±2,08 ng / ml) and increased resorption indices (15,34±1,87 nmol/L). Medications that stimulate osteogenesis and prevent bone resorption were prescribed. Conclusions: When planning dental implants and periodontal surgical intervention it is necessary to identify markers of bone remodeling to assess the structural and functional state of bone tissue and prescribe osteotrophic drugs that promote positive postoperative period.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Yi Lu ◽  
Yuanpu Peter Di ◽  
Ming Chang ◽  
Xin Huang ◽  
Qiuyan Chen ◽  
...  

Abstract Background Cigarette smoking constitutes a major lifestyle risk factor for osteoporosis and hip fracture. It is reported to impair the outcome of many clinical procedures, such as wound infection treatment and fracture healing. Importantly, although several studies have already demonstrated the negative correlation between cigarette consume and impaired bone homeostasis, there is still a poor understanding of how does smoking affect bone health, due to the lack of an adequately designed animal model. Our goal was to determine that cigarette smoke exposure impairs the dynamic bone remodeling process through induction of bone resorption and inhibition of bone formation. Methods We developed cigarette smoke exposure protocols exposing mice to environmental smoking for 10 days or 3 months to determine acute and chronic smoke exposure effects. We used these models, to demonstrate the effect of smoking exposure on the cellular and molecular changes of bone remodeling and correlate these early alterations with subsequent bone structure changes measured by microCT and pQCT. We examined the bone phenotype alterations in vivo and ex vivo in the acute and chronic smoke exposure mice by measuring bone mineral density and bone histomorphometry. Further, we measured osteoclast and osteoblast differentiation gene expression levels in each group. The function changes of osteoclast or osteoblast were evaluated. Results Smoke exposure caused a significant imbalance between bone resorption and bone formation. A 10-day exposure to cigarette smoke sufficiently and effectively induced osteoclast activity, leading to the inhibition of osteoblast differentiation, although it did not immediately alter bone structure as demonstrated in mice exposed to smoke for 3 months. Cigarette smoke exposure also induced DNA-binding activity of nuclear factor kappaB (NFκB) in osteoclasts, which subsequently gave rise to changes in bone remodeling-related gene expression. Conclusions Our findings suggest that smoke exposure induces RANKL activation-mediated by NFκB, which could be a “smoke sensor” for bone remodeling.


2021 ◽  
Vol 9 (3) ◽  
pp. 24
Author(s):  
Brian Heubel ◽  
Anja Nohe

The osteogenic effects of Bone Morphogenetic Proteins (BMPs) were delineated in 1965 when Urist et al. showed that BMPs could induce ectopic bone formation. In subsequent decades, the effects of BMPs on bone formation and maintenance were established. BMPs induce proliferation in osteoprogenitor cells and increase mineralization activity in osteoblasts. The role of BMPs in bone homeostasis and repair led to the approval of BMP2 by the Federal Drug Administration (FDA) for anterior lumbar interbody fusion (ALIF) to increase the bone formation in the treated area. However, the use of BMP2 for treatment of degenerative bone diseases such as osteoporosis is still uncertain as patients treated with BMP2 results in the stimulation of not only osteoblast mineralization, but also osteoclast absorption, leading to early bone graft subsidence. The increase in absorption activity is the result of direct stimulation of osteoclasts by BMP2 working synergistically with the RANK signaling pathway. The dual effect of BMPs on bone resorption and mineralization highlights the essential role of BMP-signaling in bone homeostasis, making it a putative therapeutic target for diseases like osteoporosis. Before the BMP pathway can be utilized in the treatment of osteoporosis a better understanding of how BMP-signaling regulates osteoclasts must be established.


Author(s):  
Giorgia Di Lorenzo ◽  
Lena M. Westermann ◽  
Timur A. Yorgan ◽  
Julian Stürznickel ◽  
Nataniel F. Ludwig ◽  
...  

Abstract Purpose Pathogenic variants in GNPTAB and GNPTG, encoding different subunits of GlcNAc-1-phosphotransferase, cause mucolipidosis (ML) II, MLIII alpha/beta, and MLIII gamma. This study aimed to investigate the cellular and molecular bases underlying skeletal abnormalities in patients with MLII and MLIII. Methods We analyzed bone biopsies from patients with MLIII alpha/beta or MLIII gamma by undecalcified histology and histomorphometry. The skeletal status of Gnptgkoand Gnptab-deficient mice was determined and complemented by biochemical analysis of primary Gnptgko bone cells. The clinical relevance of the mouse data was underscored by systematic urinary collagen crosslinks quantification in patients with MLII, MLIII alpha/beta, and MLIII gamma. Results The analysis of iliac crest biopsies revealed that bone remodeling is impaired in patients with GNPTAB-associated MLIII alpha/beta but not with GNPTG-associated MLIII gamma. Opposed to Gnptab-deficient mice, skeletal remodeling is not affected in Gnptgko mice. Most importantly, patients with variants in GNPTAB but not in GNPTG exhibited increased bone resorption. Conclusion The gene-specific impact on bone remodeling in human individuals and in mice proposes distinct molecular functions of the GlcNAc-1-phosphotransferase subunits in bone cells. We therefore appeal for the necessity to classify MLIII based on genetic in addition to clinical criteria to ensure appropriate therapy.


Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1779
Author(s):  
Ga-Ram Kim ◽  
Eun-Nam Kim ◽  
Kyoung Jin Park ◽  
Ki Hyun Kim ◽  
Gil-Saeng Jeong

Osteoblasts and osteoclasts play a pivotal role in maintaining bone homeostasis, of which excessive bone resorption by osteoclasts can cause osteoporosis and various bone diseases. However, current osteoporosis treatments have many side effects, and research on new treatments that can replace these treatments is ongoing. Therefore, in this study, the roles of ligustroside (LGS) and oleoside dimethylester (ODE), a natural product-derived compound isolated from Syringa oblata subsp. dilatata as a novel, natural product-derived osteoporosis treatments were investigated. In the results of this study, LGS and ODE inhibited the differentiation of receptor activator of nuclear factor kappa-Β ligand (RANKL)-induced RAW264.7 cells into osteoclasts without cytotoxicity, and down-regulated the activity of TRAP, a specific biomarker of osteoclasts. In addition, it inhibited bone resorption and actin ring formation, which are important functions and features of osteoclasts. Also, the effects of LGS and ODE on the mitogen-activated protein kinase (MAPK) and nuclear factor kappa-light-chain-enhancer of activated B (NF-κB) and phosphoinositide 3-kinases (PI3K)/ protein kinase B (Akt)/mechanistic target of rapamycin (mTOR) signaling pathways that play important roles in osteoclast differentiation were evaluated. In the results, LGS and ODE downregulated the phosphorylation of RANKL-induced MAPK and PI3K/Akt/mTOR proteins in a concentration-dependent manner, translocation of NF-κB into the nucleus was inhibited. As a result, the compounds LGS and ODE isolated from S. oblate subsp. dilatata effectively regulated the differentiation of RANKL-induced osteoclasts and inhibited the phosphorylation of signaling pathways that play a pivotal role in osteoclast differentiation. Therefore, these results suggest the possibility of LGS and ODE as new natural product treatments for bone diseases caused by excessive osteoclasts.


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