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Concavities of Crystalline Sintered Hydroxyapatite-Based Macroporous Bioreactors Initiate the Spontaneous Induction of Bone Formation
Published in Ugo Ripamonti, The Geometric Induction of Bone Formation, 2020
In unique experimentation in the Carcharhiniform selachian Carcharhinus obscurus shark, coral-derived macroporous constructs, 20 mm in length, 11 mm in diameter, were implanted in the dorsal muscles of a number of adolescent C. obscurus (Ripamonti 2018b; Ripamonti et al. 2018). Retrieved specimens, often damaged and crushed by the powerful muscular activity of the selachian fishes, were processed for histological analyses, and one control specimen was amenable to proper histological processing and sectioning with successful staining of the newly formed tissues within the macroporous spaces (Fig. 5.18). Chondrogenesis developed within the macroporous spaces without any application of soluble morphogenetic signals (Fig. 5.18). Panel (a) shows the induction of cartilage material directly against the calcium phosphate-based bioreactor (dark blue arrow) with columns of progressively differentiating chondroblasts (lightblue arrows), patterning the newly formed cartilage as in mammalian embryonic development (Reddi 2000; Ripamonti 2017; Ripamonti et al. 2018). Our published paper speculated that the micro-inductive micro-environment of the coral-derived macroporous bioreactors engineers cartilaginous columnar condensations as seen in the mammalian growth plate counterpart (Ripamonti et al. 2018). Panel (b) shows the induction of cartilage (Fig. 18b white arrow) detailing the columnar arrangement of chondroblasts/chondrocytes as in the mammalian growth plate (Fig. 18b light blue arrow).
Bone and Cartilage
Published in George W. Casarett, Radiation Histopathology: Volume II, 2019
Zone 2 — This is the zone of proliferation of chondroblasts in longitudinal columns. In the longitudinally growing bone, the chondroblasts of this zone behave as vegetative intermitotic cells, dividing frequently to produce daughter cells, some of which remain as vegetative intermitotic cells, and some of which grow and differentiate in the subsequent zones of the columns. These vegetative intermitotic chondroblasts are relatively radiosensitive.
Articular Cartilage
Published in Manoj Ramachandran, Tom Nunn, Basic Orthopaedic Sciences, 2018
Tim S. Waters, Nima Heidari, George Bentley
The articular chondrocyte is derived from uncommitted mesenchymal stem cells (MSCs). Chondroblasts proliferate during fetal development, and the majority of cartilage transforms into bone through endochondral ossification, with the growth plate and cartilaginous epiphyses persisting after birth. At skeletal maturity, the articular surface is the only remaining cartilaginous part. Articular chondrocytes and growth plate chondrocytes represent different pathways of terminal differentiation. The matrix and synovial fluid environment play extremely important roles in the maintenance of the phenotype of articular chondrocytes. Once committed to one of these pathways, the cell phenotype is not usually reversible, although if growth plate chondrocytes are positioned in an articular defect the surface layers take on the appearance of articular cartilage.
Latest models for the discovery and development of rheumatoid arthritis drugs
Published in Expert Opinion on Drug Discovery, 2022
Bartosz Szostak, Anna Gorący, Bartłomiej Pala, Jakub Rosik, Łukasz Ustianowski, Andrzej Pawlik
Cartilage is another element of the joint that could hardly be mimicked in a 2D model. It is mostly acellular with a few chondroblasts and chondrocytes resuspended in a very well-organized extracellular matrix (ECM) [120]. Inflammation during the course of RA impairs the function and viability of cells [121,122]. In vivo, chondrocytes are influenced by numerous mechanical stimuli that, in a 3D model, might be imitated far better than in a monolayer. Moreover, there are a variety of scaffolds – composed of collagens, hyaluronic acid, and chitosan [123,124] – that naturally compose tissue or gels that mimic the architecture well [113,125]. Models similar to the one described by Peck et al. [113] have been used to validate pathological alterations of chondrocyte phenotype or to test anti-rheumatic agents [112,125]. Scaffold-free models, which are based on cell organization stimulated by mechanical load, have been established and are used in the preclinical stages of research [126–129]. Akin to the synovium model, widely available MSCs are a perfect source of cells, as it is possible for them to differentiate into chondrocytes [130,131].
Specification of Sprouty2 functions in osteogenesis in in vivo context
Published in Organogenesis, 2019
Barbora Vesela, Eva Svandova, Maria Hovorakova, Renata Peterkova, Adela Kratochvilova, Martina Pasovska, Alice Ramesova, Herve Lesot, Eva Matalova
Transgenic mice lacking SPRY and SPRED (Sprouty-related, EVH1 domain-containing proteins) family proteins show abnormalities in endochondral (long) bones including a decreased bone growth (achondroplasia-like phenotype) and decreased trabecular bone mass.3–5 Endochondral bones, unlike the intramembranous ones, involve a chondrogenic developmental step. The developing growth plate may be divided into three compartments: an external fibrous tissue surrounding the periphery, a cartilaginous, and a bony tissue. The cartilaginous part consists of several zones, where chondrocytes differentiate towards the diaphysis: the resting zone, where a pool of less differentiated chondroblasts is localized, proliferating zone, where chondroblasts multiply and further differentiate, and zone of hypertrophy undergoing calcification, degradation and replacement by osseous tissue. The calcifying matrix of cartilage starts to be removed by osteoclasts/chondroclasts in the line of erosion, and the formation of the primary spongiosa involves a cooperation between osteoblasts and osteoclasts in the zone of ossification.6
Cell membrane capsule: a novel natural tool for antitumour drug delivery
Published in Expert Opinion on Drug Delivery, 2019
Hai Zou, Jing Zhu, Dong-Sheng Huang
Using chemicals to stimulate cells is one of the important methods to produce EVs. Saha et al. reported that the number of EVs, mostly exosomes, secreted by primary monocytes and THP-1 mononuclear cells was increased in the presence of alcohol, a phenomenon which showed a concentration and time dependence [131]. Increased intracellular calcium levels in erythrocytes could cause EV biogenesis [132]. In addition, ATP depletion and exposure to membranotropic and haemolytic agents triggered similar effects [80,82]. Cytochalasin B (CB) was investigated by some researchers to induce EV production by cells [34,133,134]. CB interferes with cytokinesis, but not with nuclear division, to reversibly induce branching of cells [134]. While capable of inducing branching in many immature cell types such as myoblasts, fibroblasts, and non-encapsulated chondroblasts, these changes were not observed in more mature cell types such as myotubular myoblasts, erythrocytes, amnion cells, encapsulated chondroblasts, and HeLa cells. Pick et al. successfully produced EVs from cells in their study investigating the effects of CB on human embryonic kidney HEK293 cells [34]. Treatment with CB resulted in the appearance of tubular protrusions in these cells. Agitation of CB-treated cells led to the release of EVs with maintained orientation and functional activity of cell surface receptors, ion pumps and cytosolic proteins.