A New System for Cyclical Tensile Loading of Cultured Connective Tissue Cells in a Three-Dimensional Gel Matrix

Author(s):  
Chantal Dussault ◽  
Dominic I. Young ◽  
Neil A. Duncan

Cells can sense and respond to the mechanical load present in connective tissue. Cell shape has been correlated to the local mechanical environment in a variety of connective tissue cells [1,2], and cell deformation has been suggested as a mechanism to transduce tissue mechanical signals to the nucleus via the cytoskeleton [3,4]. Though many connective tissues are subjected to tensile loads, to date very limited investigations have been reported on the effect of tensile loads on the mechano-biology of isolated cells. To apply tensile loads to isolated connective tissue cells requires a three-dimensional (3D) matrix to maintain cell phenotype, and a highly elastic matrix to enable the large deformations that the cells experience in situ.

1914 ◽  
Vol 19 (2) ◽  
pp. 129-142 ◽  
Author(s):  
J. Parsons Schaeffer

A study of the histogenesis of elastic tissue in the embryonic ductus arteriosus of Sus scrofa is in accord with the theory that elastic fibrils are directly differentiated in the outlying portion of the protoplasm of the early connective tissue cell. In the occlusion of the postfetal ductus arteriosus of Sus scrofa there is early a hypertrophy of the internal elastic membrane. Subsequently there takes place a marked delamination of the thickened internal elastic membrane in the production of new and independent elastic fibers and lamellæ. The formation of new elastic fibers from preformed elastic tissue is most abundant where the postfetal contraction of the ductus arteriosus is least marked. These new elastic fibers play an important part in the occlusion of the lumen of the postfetal ductus. Aside from the extensive formation of elastic fibers from preformed elastic tissue, in the occlusion of the lumen of the postfetal ductus arteriosus of Sus scrofa, there are also some elastic fibrils formed from non-elastic elements, apparently from connective tissue cells. In some recent preliminary work on ligations of the common carotid artery there was found, after an interval of from eight to twelve days, at some points between the ligatures, a slight but obvious cellular thickening of the so-called subendothelial stratum. Some of these connective tissue cells may have wandered from the other coats of the vessel, through the inner elastic membrane into the subendothelial stratum; others may have proliferated from cells in situ. Specific stains revealed near the periphery of some of these cells, i. e., in the outlying portion of the exoplasm, very delicate elastic fibrils, apparently the product of protoplasmic activity.


1913 ◽  
Vol 18 (2) ◽  
pp. 183-186 ◽  
Author(s):  
Peyton Rous

Connective tissue cells of chick embryos and cells of a chicken sarcoma, proliferating in vitro, soon render acid the plasma about them, but they nevertheless continue to grow well. Evidently the tissue cell will withstand a considerably greater change in the reaction of the fluids about it than has usually been supposed. Under conditions of in vitro life in plasma, which do not provide for an artificial circulation, the acid produced by growing tissues diffuses only slowly and is subject to little dilution from this source. About tissues which grow very rapidly in vitro, as, for example, tumor tissues, there must be a marked concentration of metabolic products, and this may largely account for the poor results of attempts at the continuous propagation of such tissues in vitro.


2021 ◽  
Author(s):  
Alexandre Grimaldi ◽  
Glenda Evangelina Comai ◽  
Sebastien Mella ◽  
Shahragim Tajbakhsh

How distinct cell fates are manifested by direct lineage ancestry from bipotent progenitors, or by specification of individual cell types within a field of cells is a key question for understanding the emergence of tissues. The interplay between skeletal muscle progenitors and associated connective tissues cells provides a model for examining how muscle functional units are established. Most craniofacial structures originate from the vertebrate-specific neural crest cells except in the dorsal portion of the head, where they arise from cranial mesoderm. Here, using multiple lineage-traced single cell RNAseq, advanced computational methods and in situ analyses, we identify Myf5+ bipotent progenitors that give rise to both muscle and juxtaposed connective tissue. Following this bifurcation, muscle and connective tissue cells retain complementary signalling features and maintain spatial proximity. Interruption of upstream myogenic identity shifts muscle progenitors to a connective tissue fate. Interestingly, Myf5-derived connective tissue cells, which adopt a novel regulatory signature, were not observed in ventral craniofacial structures that are colonised by neural crest cells. Therefore, we propose that an ancestral program gives rise to bifated muscle and connective tissue cells in skeletal muscles that are deprived of neural crest.


Author(s):  
M Eastwood ◽  
D A McGrouther ◽  
R A Brown

The repair and maintenance of connective tissues is performed predominately by a mesenchymal cell known as a fibroblast. The activity of this cell is regulated, in part, by changes in the mechanical environment in which it resides. The authors have addressed some of the questions related to the fibroblast and how it responds to mechanical stimulation. An in vitro model, the ‘culture force monitor’, and its derivative, the tensioning culture force monitor have been developed enabling quantitative investigations to be performed on fibroblasts in a collagen lattice. Results have shown that a fibroblast can generate a force of approximately 10−10 N, as a result of change in cell shape and attachment, while in a three-dimensional collagen lattice. Application of a physiologically similar mechanical load has shown that fibroblasts have the ability to maintain a tensional homeostasis of approximately 40–60×10−5 N per million cells, change cellular morphology in a predictable manner and biochemically modify their resident environment.


2014 ◽  
Vol 6 (3) ◽  
Author(s):  
Sunny Wangko ◽  
Ronny Karundeng

Abstract: Connective tissue is distributed in all parts of the body and its main function is to connect cells and tissues. Most of the embryonic connective tissues are derived from embryonal messenchymal tissues. There are a variety of connective tissues which are compatible with their functions and locations. The general difference of all connective tissues is the arrangement and composition of intercellular matrix. Connective tissues are composed of two major components: cells and intercellular matrices. Connective tissue cells, fixed cells or wandering cells, have their special functions which support each other to maintain the optimal histophysiology of the connective tissue.Keywords: connective tissues, cells, histophysiologyAbstrak: Jaringan ikat tersebar luas di seluruh bagian tubuh dengan fungsi utama untuk menghubungkan berbagai komponen sel atau jaringan. Hampir seluruh jaringan ikat embriologik berasal dari jaringan mesensimal embrional. Terdapat berbagai jenis jaringan ikat yang sesuai dengan fungsi dan lokasinya. Perbedaan utama dari berjenis-jenis jaringan ikat tersebut berdasarkan susunan dan komposisi matriks intersel. Jaringan ikat terdiri dari dua komponen dasar utama yaitu sel dan matriks intersel. Sel-sel jaringan ikat baik yang tetap maupun yang bebas mempunyai fungsi khusus masing-masing yang saling melengkapi untuk mempertahankan keutuhan histofisiologi jaringan ikat.Kata kunci: jaringan ikat, sel, histofisiologi


2019 ◽  
Author(s):  
Dominik Egger ◽  
Ana Catarina Oliveira ◽  
Barbara Mallinger ◽  
Hatim Hemeda ◽  
Verena Charwat ◽  
...  

AbstractMesenchymal stem/stromal cells (MSCs) are considered an important candidate in cell therapy and tissue engineering approaches. The culture of stem cells in a 3D environment is known to better resemble the in vivo situation and to promote therapeutically relevant effects in isolated cells. Therefore, the aim of this study was to develop an approach for the isolation of MSCs from adipose tissue into a 3D environment. Furthermore, the use of cryoprotective medium for cryopreservation of whole adipose tissue was evaluated. For the isolation of MSCs, a novel human platelet lysate-based hydrogel was used as matrix and the migration, yield, viability and metabolic activity of cells from the 3D matrix were compared to cells from 2D explant culture. Also, the surface marker profile and differentiation capacity of MSCs from the 3D matrix were evaluated and compared to MSCs from isolation by enzymatic treatment. We found that cryopreservation of whole adipose tissue is feasible, and therefore adipose tissue can be stored and is available for MSC isolation on demand. Also, we demonstrate the isolation of MSCs into the 3D matrix and that cells from this condition display a similar phenotype and differentiation capacity like MSCs derived by traditional isolation procedure. The presented approach allows, for the first time, to isolate MSCs directly into a soft 3D hydrogel environment, avoiding any contact to a 2D plastic culture surface.Significance StatementIn this paper we present a new method for the isolation of mesenchymal stem cells. Usually, these cells grow on two-dimensional plastic surfaces which is far away from their physiologic environment. Our new method allows for the first time the direct outgrowth of cells from primary tissue into a three-dimensional environment, avoiding any contact to a two-dimensional plastic surface. In future, this will allow an entirely three-dimensional in vitro cultivation of stem cells. Using 3D isolated cells will probably also increase the physiologic relevance of in vitro models.


Author(s):  
C. N. Sun ◽  
H. J. White

Previously, we have reported on extracellular cross-striated banded structures in human connective tissues of a variety of organs (1). Since then, more material has been examined and other techniques applied. Recently, we studied a fibrocytic meningioma of the falx. After the specimen was fixed in 4% buffered glutaraldehyde and post-fixed in 1% buffered osmium tetroxide, other routine procedures were followed for embedding in Epon 812. Sections were stained with uranyl acetate and lead citrate. There were numerous cross striated banded structures in aggregated bundle forms found in the connecfive tissue of the tumor. The banded material has a periodicity of about 450 Å and where it assumes a filamentous arrangement, appears to be about 800 Å in diameter. In comparison with the vicinal native collagen fibrils, the banded material Is sometimes about twice the diameter of native collagen.


Author(s):  
Badrinath Roysam ◽  
Hakan Ancin ◽  
Douglas E. Becker ◽  
Robert W. Mackin ◽  
Matthew M. Chestnut ◽  
...  

This paper summarizes recent advances made by this group in the automated three-dimensional (3-D) image analysis of cytological specimens that are much thicker than the depth of field, and much wider than the field of view of the microscope. The imaging of thick samples is motivated by the need to sample large volumes of tissue rapidly, make more accurate measurements than possible with 2-D sampling, and also to perform analysis in a manner that preserves the relative locations and 3-D structures of the cells. The motivation to study specimens much wider than the field of view arises when measurements and insights at the tissue, rather than the cell level are needed.The term “analysis” indicates a activities ranging from cell counting, neuron tracing, cell morphometry, measurement of tracers, through characterization of large populations of cells with regard to higher-level tissue organization by detecting patterns such as 3-D spatial clustering, the presence of subpopulations, and their relationships to each other. Of even more interest are changes in these parameters as a function of development, and as a reaction to external stimuli. There is a widespread need to measure structural changes in tissue caused by toxins, physiologic states, biochemicals, aging, development, and electrochemical or physical stimuli. These agents could affect the number of cells per unit volume of tissue, cell volume and shape, and cause structural changes in individual cells, inter-connections, or subtle changes in higher-level tissue architecture. It is important to process large intact volumes of tissue to achieve adequate sampling and sensitivity to subtle changes. It is desirable to perform such studies rapidly, with utmost automation, and at minimal cost. Automated 3-D image analysis methods offer unique advantages and opportunities, without making simplifying assumptions of tissue uniformity, unlike random sampling methods such as stereology.12 Although stereological methods are known to be statistically unbiased, they may not be statistically efficient. Another disadvantage of sampling methods is the lack of full visual confirmation - an attractive feature of image analysis based methods.


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