Journal articles: 'Collagène dense'

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Zou, Chao, Wen Jian Weng, Xu Liang Deng, Kui Cheng, Pi Yi Du, Ge Shen, and Gao Rong Han. "Influence of Collagen Status on Microstructures of Porous Collagen/TCP Composites." Key Engineering Materials 330-332 (February 2007): 495–98. http://dx.doi.org/10.4028/www.scientific.net/kem.330-332.495.

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Two starting collagens, sponge and floc collagen, were used to prepare collagen/tricalcium phosphate (TCP) composites. The resulting composites were porous and had 200μm pore size. However, there was a difference in the microstructure of the pore walls for the composites derived from the two collagens, the pore walls in sponge collagen/TCP composite were still porous and had 200 nm micropores size, TCP particles were trapped in collagen matrices. While floc collagen/TCP composite had smooth and dense walls in which TCP particles were embedded. The difference could be attributed to the starting collagen with different status. Sponge collagen has a soft structure, which easily becomes disassembled fibrils during alkali treatment, the disassembled fibrils are integrated again to form a dense morphology for pore walls after freeze-drying. While floc collagen has already a low disassembly degree, the alkali treatment could not be able to separate the fibrils, this remains as micropores in pore walls after freeze-drying. Both porous composites are significant in bone tissue engineering or regeneration. MTT test results showed the two composites had good cytocompatibility, and sponge collagen/TCP composite was somewhat better than floc collagen/TCP composite, which could result from that micropores derived roughness in pore walls of sponge collagen/TCP composite is suitable for cell growth.

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Aplin, J. D., S. Campbell, and T. D. Allen. "The extracellular matrix of human amniotic epithelium: ultrastructure, composition and deposition." Journal of Cell Science 79, no. 1 (November 1, 1985): 119–36. http://dx.doi.org/10.1242/jcs.79.1.119.

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Ultrastructural comparisons have been made between human amnion extracellular matrix in tissue and cell culture. Immunochemical analysis of matrix deposited by monolayers of cultured amnion epithelial cells has also been undertaken. The basal cell surfaces are highly invaginated with an associated basal lamina that is more electron dense at the distal tips of basal cell processes where hemidesmosomes are frequent. Immediately below the lamina densa is a zone rich in collagen bundles. In the underlying stroma two types of fibril predominate, one striated of 50 nm diameter and one of 18 nm diameter. The observations suggest that at gestational term the epithelial cells are still active in the production of matrix. Secretion appears to occur into invaginations in the basal cell surface where a loosely organized mixture of stromal-type and basal laminal-type aggregates is formed. In culture on plastic, cells also deposit a mixture of basal laminal (type IV collagen + laminin) and stromal (collagens type I + III) components as well as fibronectin. However, segregation into a true basal lamina with underlying stroma does not occur in vitro, suggesting the need for an organized subcellular template to complete matrix morphogenesis. The in vitro and in vivo evidence suggest that the epithelium contributes to the subjacent dense collagenous zone as well as to the basal lamina.

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Keene, D. R., L. Y. Sakai, G. P. Lunstrum, N. P. Morris, and R. E. Burgeson. "Type VII collagen forms an extended network of anchoring fibrils." Journal of Cell Biology 104, no. 3 (March 1, 1987): 611–21. http://dx.doi.org/10.1083/jcb.104.3.611.

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Type VII collagen is one of the newly identified members of the collagen family. A variety of evidence, including ultrastructural immunolocalization, has previously shown that type VII collagen is a major structural component of anchoring fibrils, found immediately beneath the lamina densa of many epithelia. In the present study, ultrastructural immunolocalization with monoclonal and monospecific polyclonal antibodies to type VII collagen and with a monoclonal antibody to type IV collagen indicates that amorphous electron-dense structures which we term "anchoring plaques" are normal features of the basement membrane zone of skin and cornea. These plaques contain type IV collagen and the carboxyl-terminal domain of type VII collagen. Banded anchoring fibrils extend from both the lamina densa and from these plaques, and can be seen bridging the plaques with the lamina densa and with other anchoring plaques. These observations lead to the postulation of a multilayered network of anchoring fibrils and anchoring plaques which underlies the basal lamina of several anchoring fibril-containing tissues. This extended network is capable of entrapping a large number of banded collagen fibers, microfibrils, and other stromal matrix components. These observations support the hypothesis that anchoring fibrils provide additional adhesion of the lamina densa to its underlying stroma.

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Jaziri, Abdul Aziz, Rossita Shapawi, Ruzaidi Azli Mohd Mokhtar, Wan Norhana Md Noordin, and Nurul Huda. "Physicochemical and Microstructural Analyses of Pepsin-Soluble Collagens Derived from Lizardfish (Saurida tumbil Bloch, 1795) Skin, Bone and Scales." Gels 8, no. 8 (July 27, 2022): 471. http://dx.doi.org/10.3390/gels8080471.

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Reducing food waste is critical for sustainability. In the case of fish processing, more than sixty percent of by-products are generated as waste. Lizardfish (Saurida tumbil Bloch, 1795) is an economically important species for surimi production. To address waste disposal and maximize income, an effective utilization of fish by-products is essential. This study aims to isolate and characterize pepsin-soluble collagens from the skin, bone and scales of lizardfish. Significant differences (p < 0.05) in the yields of collagen were noted with the highest yield recorded in pepsin-soluble skin collagen (PSSC) (3.50 ± 0.11%), followed by pepsin-soluble bone collagen (PSBC) (3.26 ± 0.10%) and pepsin-soluble scales collagen (PSCC) (0.60 ± 0.65%). Through SDS–polyacrylamide gel electrophoresis, the presence of two alpha chains were noted and classified as type I. From Fourier transform infrared spectroscopy (FTIR) analysis, the triple-helix structure of the collagen was maintained. The X-ray diffraction and UV visible spectra characteristics of the lizardfish collagens in this study are similar to the previously reported fish collagens. In terms of thermostability, PSSC (Tmax = 43.89 °C) had higher thermostability in comparison to PSBC (Tmax = 31.75 °C) and PSCC (Tmax = 30.54 °C). All pepsin-soluble collagens were highly soluble (>70%) in acidic conditions (particularly at pH 4.0) and at low sodium chloride concentrations (0–30 g/L). Microstructural analysis depicted that all extracted collagens were multi-layered, irregular, dense, sheet-like films linked by random coiled filaments. Overall, pepsin-soluble collagens from lizardfish skin, bone and scales could serve as potential alternative sources of collagens.

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Fatiroi, Nurul Syazwanie, Abdul Aziz Jaziri, Rossita Shapawi, Ruzaidi Azli Mohd Mokhtar, Wan Norhana Md Noordin, and Nurul Huda. "Biochemical and Microstructural Characteristics of Collagen Biopolymer from Unicornfish (Naso reticulatus Randall, 2001) Bone Prepared with Various Acid Types." Polymers 15, no. 4 (February 20, 2023): 1054. http://dx.doi.org/10.3390/polym15041054.

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Biopolymer-like collagen has great industrial potential in terms of its excellent properties, such as strong biocompatibility, high degradability, and low antigenicity. Collagen derived from fish by-products is preferable as it is safer (free from transmittable diseases) and acceptable to most religious beliefs. This study aimed to characterize the unicornfish (Naso reticulatus Randall, 2001) bone collagens prepared with different type of acids, i.e., acetic acid, lactic acid, and citric acid. A higher yield (Y) (p < 0.05) was obtained in the citric-acid-soluble collagen (CASC) (Y = 1.36%), followed by the lactic-acid-soluble collagen (LASC) (Y = 1.08%) and acetic-acid-soluble collagen (AASC) (Y = 0.40%). All extracted collagens were classified as type I due to the presence of 2-alpha chains (α1 and α2). Their prominent absorption spectra were located at the wavelengths of 229.83 nm to 231.17 nm. This is similar to wavelengths reported for other fish collagens. The X-ray diffraction (XRD) and infrared (IR) data demonstrated that the triple-helical structure of type I collagens was still preserved after the acid-extraction process. In terms of thermal stability, all samples had similar maximum transition temperatures (Tmax = 33.34–33.51 °C). A higher relative solubility (RS) of the unicornfish bone collagens was observed at low salt concentration (0–10 g/L) (RS > 80%) and at acidic condition (pH 1.0 to pH 3.0) (RS > 75%). The extracted collagen samples had an irregular and dense flake structure with random coiled filaments. Overall, bones of unicornfish may be used as a substitute source of collagen.

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Matarsim, Nur Nadiah, Abdul Aziz Jaziri, Rossita Shapawi, Ruzaidi Azli Mohd Mokhtar, Wan Norhana Md Noordin, and Nurul Huda. "Type I Collagen from the Skin of Barracuda (Sphyraena sp.) Prepared with Different Organic Acids: Biochemical, Microstructural and Functional Properties." Journal of Functional Biomaterials 14, no. 2 (February 3, 2023): 87. http://dx.doi.org/10.3390/jfb14020087.

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This study was carried out to compare the extractability and characteristics of barracuda (Sphyraena sp.) skin collagen using various organic acids. Acetic-solubilized collagen (ASBS), lactic-solubilized collagen (LSBS) and citric-solubilized collagen (CSBS) yielded 6.77 g/100 g, 10.06 g/100 g and 8.35 g/100 g, respectively, and those yields were significantly different (p < 0.05). All acid-solubilized collagens were considered as type I because of their two alpha chains (α1 and α2) detected in acrylamide gel after electrophoresis. Ultraviolet–visible (UV–vis) analysis confirmed that ASBS, LSBS and CSBS had similar absorption peaks (230.5 nm) and the results were in accordance with other fish collagens. Under infrared (IR) and X-ray diffraction (XRD) analysis, the triple helical structure of type I collagens extracted from barracuda skin was maintained. From a thermostability study, all type I collagens showed a higher maximum transition temperature (Tmax = 40.16 to 41.29 °C) compared to other fish skin collagens. In addition, the functional properties of the extracted collagens revealed the ASBS had higher water and oil absorption capacities than the CSBS and LSBS samples. The highest level of the emulsion ability index (EAI) (>200 m2/g) was detected under acidic conditions (pH 4), while lower EAIs were recorded under the alkaline (pH 10) and neutral treatments (pH 7). All type I collagens had a higher relative solubility (>60%) at a low pH test but the solubility level sharply decreased at a neutral pH. In addition to this, a lower concentration of NaCl (0–20 g/L) showed the higher percentage of solubility (>60%) while adding over 30 g/L of NaCl decreased solubility (>40%). From a microstructural test, all type I samples had an irregular and dense flake structure with random coiled filaments. Overall, collagen extracted from the barracuda skin may be applied as an alternative collagen from an industry perspective.

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Ebelt, Nancy D., Vic Zamloot, Edith Zuniga, Kevin B. Passi, Lukas J. Sobocinski, Cari A. Young, Bruce R. Blazar, and Edwin R. Manuel. "Collagenase-Expressing Salmonella Targets Major Collagens in Pancreatic Cancer Leading to Reductions in Immunosuppressive Subsets and Tumor Growth." Cancers 13, no. 14 (July 16, 2021): 3565. http://dx.doi.org/10.3390/cancers13143565.

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Therapeutic resistance in pancreatic ductal adenocarcinoma (PDAC) can be attributed, in part, to a dense extracellular matrix containing excessive collagen deposition. Here, we describe a novel Salmonella typhimurium (ST) vector expressing the bacterial collagenase Streptomyces omiyaensis trypsin (SOT), a serine protease known to hydrolyze collagens I and IV, which are predominantly found in PDAC. Utilizing aggressive models of PDAC, we show that ST-SOT selectively degrades intratumoral collagen leading to decreases in immunosuppressive subsets, tumor proliferation and viability. Ultimately, we found that ST-SOT treatment significantly modifies the intratumoral immune landscape to generate a microenvironment that may be more conducive to immunotherapy.

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Walchli, C., M. Koch, M. Chiquet, B. F. Odermatt, and B. Trueb. "Tissue-specific expression of the fibril-associated collagens XII and XIV." Journal of Cell Science 107, no. 2 (February 1, 1994): 669–81. http://dx.doi.org/10.1242/jcs.107.2.669.

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Interstitial collagen fibrils form the supporting scaffold of all connective tissues. The synthesis of this framework is subject to a precise spatial and temporal regulation in order to meet the mechanical needs of every tissue type. A subgroup of non-fibrillar collagens termed FACIT seems to play a role in this regulation by providing specific molecular bridges between fibrils and other matrix components. Collagens XII and XIV represent such FACIT molecules and occur preferentially in tissues containing banded type I collagen fibrils. We have used the techniques of indirect immunofluorescence and in situ hybridization to investigate the expression patterns of the two molecules during chicken embryonic development. We detected specific differences in these patterns, which may be related to the respective functions of the two proteins within the connective tissues. Collagen XIV was expressed at very few sites in the 6-day-old embryo, but occurred in virtually every collagen I-containing tissue (skeletal muscle, cardiac muscle, gizzard, tendon, periosteum, nerve) by the end of embryonic development. In contrast, collagen XII was fairly abundant in the 6-day-old embryo but was, at later stages, restricted to only a few dense connective tissue structures (bone, tendon, gizzard). Thus, our results suggest that collagen XII and collagen XIV serve different functions during embryonic development although their structures are highly similar.

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Itoh, Yoshifumi, Noriko Ito, Hideaki Nagase, Richard D. Evans, Sarah A. Bird, and Motoharu Seiki. "Cell Surface Collagenolysis Requires Homodimerization of the Membrane-bound Collagenase MT1-MMP." Molecular Biology of the Cell 17, no. 12 (December 2006): 5390–99. http://dx.doi.org/10.1091/mbc.e06-08-0740.

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Pericellular degradation of interstitial collagens is a crucial event for cells to migrate through the dense connective tissue matrices, where collagens exist as insoluble fibers. A key proteinase that participates in this process is considered to be membrane-type 1 matrix metalloproteinase (MT1-MMP or MMP-14), but little is known about the mechanism by which it cleaves the insoluble collagen. Here we report that homodimerization of MT1-MMP through its hemopexin (Hpx) domain is essential for cleaving type I collagen fibers at the cell surface. When dimerization was blocked by coexpressing either a membrane-bound or a soluble form of the Hpx domain, cell surface collagenolytic activity was inhibited in a dose-dependent manner. When MMP-13, a soluble collagenase active as a monomer in solution, was expressed as a membrane-anchored form on the cell surface, homodimerization was also required to cleave collagen. Our results introduce a new concept in that pericellular collagenolysis is regulated by correct molecular assembly of the membrane-anchored collagenase, thereby governing the directionality of the cell to migrate in tissue.

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Short, Ben. "Dense collagen kindles invadopodia formation." Journal of Cell Biology 208, no. 3 (February 2, 2015): 252. http://dx.doi.org/10.1083/jcb.2083iti3.

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Semich, R., and H. Robenek. "Organization of the cytoskeleton and the focal contacts of bovine aortic endothelial cells cultured on type I and III collagen." Journal of Histochemistry & Cytochemistry 38, no. 1 (January 1990): 59–67. http://dx.doi.org/10.1177/38.1.1688450.

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We investigated the organization of the cytoskeleton and the focal contacts of bovine aortic endothelial cells cultured on type I and III collagen. The influence of these collagens on cell morphology and the distribution pattern of actin, vimentin, talin, and vinculin was analyzed by light microscopy, conventional electron microscopy, immunofluorescence, and immunogold labeling after lysis-squirting. Whereas the morphology of the endothelial cells is not markedly influenced, the structure of the cytoskeleton and the focal contacts of the cells are altered by the different collagen types. Stress fibers are more distinct in cells grown on type I collagen; cells on type III collagen show a more diffuse distribution of actin molecules. Intermediate filaments seem not to be affected by the collagens. The areas of focal contacts are larger in cells on type I collagen. Additionally, the labeling pattern of talin and vinculin is denser in focal contacts of cells grown on type I collagen. These results suggest an important role of the type of collagen in mediation of the organization of the microfilament system and the adhesion structures of bovine aortic endothelial cells in culture.

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Ahmed, Zara, Lydia C. Powell, Navid Matin, Andrew Mearns-Spragg, Catherine A. Thornton, Ilyas M. Khan, and Lewis W. Francis. "Jellyfish Collagen: A Biocompatible Collagen Source for 3D Scaffold Fabrication and Enhanced Chondrogenicity." Marine Drugs 19, no. 8 (July 22, 2021): 405. http://dx.doi.org/10.3390/md19080405.

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Osteoarthritis (OA) is a multifactorial disease leading to degeneration of articular cartilage, causing morbidity in approximately 8.5 million of the UK population. As the dense extracellular matrix of articular cartilage is primarily composed of collagen, cartilage repair strategies have exploited the biocompatibility and mechanical strength of bovine and porcine collagen to produce robust scaffolds for procedures such as matrix-induced chondrocyte implantation (MACI). However, mammalian sourced collagens pose safety risks such as bovine spongiform encephalopathy, transmissible spongiform encephalopathy and possible transmission of viral vectors. This study characterised a non-mammalian jellyfish (Rhizostoma pulmo) collagen as an alternative, safer source in scaffold production for clinical use. Jellyfish collagen demonstrated comparable scaffold structural properties and stability when compared to mammalian collagen. Jellyfish collagen also displayed comparable immunogenic responses (platelet and leukocyte activation/cell death) and cytokine release profile in comparison to mammalian collagen in vitro. Further histological analysis of jellyfish collagen revealed bovine chondroprogenitor cell invasion and proliferation in the scaffold structures, where the scaffold supported enhanced chondrogenesis in the presence of TGFβ1. This study highlights the potential of jellyfish collagen as a safe and biocompatible biomaterial for both OA repair and further regenerative medicine applications.

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Furuyama, A., and K. Mochitate. "Assembly of the exogenous extracellular matrix during basement membrane formation by alveolar epithelial cells in vitro." Journal of Cell Science 113, no. 5 (March 1, 2000): 859–68. http://dx.doi.org/10.1242/jcs.113.5.859.

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We found that immortalized alveolar type II epithelial cells (SV40-T2 cells) that were cultured on dense fibrillar collagen supplemented with Matrigel gel formed a thin and continuous lamina densa beneath them. Immunohistochemical analysis of laminin-1, type IV collagen, entactin (nidogen) and perlecan in the culture indicated that all these components were integrated into a sheet structure of basement membrane beneath the cells. Analysis of the temporal and spatial distribution of the basement membrane macromolecules revealed that the initial deposits of laminin-1 and entactin were significantly greater in area in the presence of Matrigel. These globular deposits and the coarse mesh of basement membrane macromolecules developed into a flat membranous basement membrane. In the absence of Matrigel, the SV40-T2 cells failed to form a continuous lamina densa, and the deposits stayed in the coarse mesh. The major biotinylated Matrigel components that were integrated into the basement membrane were laminin-1 and entactin. Furthermore, SV40-T2 cells supplemented with exogenous laminin-1 alone as well as laminin-1 contaminated with entactin formed a continuous lamina densa. These results indicate that the laminin-1 and entactin supplied from the Matrigel were incorporated into a basement membrane beneath the SV40-T2 cells, and contributed to the formation of basement membrane. Therefore, we concluded that the alveolar epithelial cells synthesize laminin-1, entactin, type IV collagen, and perlecan, but that they also needed to assemble exogenous laminin-1 into the basement membrane to complete its formation in vitro.

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Linsenmayer, T. F., D. E. Birk, C. M. Linsenmayer, M. K. Gordon, J. K. Marchant, and J. M. Fitch. "Heterotypic fibrils and stabilizing collagens in corneal development." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 172–73. http://dx.doi.org/10.1017/s0424820100085162.

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Our studies on the embryonic development of the chick cornea have recently yielded information suggesting possible roles for different types and classes of collagens. The chick cornea develops through a series of precisely controlled temporal and spatial events involving cell differentiation, migration and extracellular matrix production and assembly. Each event involves, and is possibly dictated by, dramatic changes in the major molecular components of the extracellular matrix. Corneal morphogenesis begins with the formation of the primary corneal stroma, a dense subepithelial matrix consisting of orthogonally arranged, horizontal layers of collagen fibrils. Each layer is one fibril thick. This stroma then rapidly swells and immediately thereafter is invaded by pericorneal mesenchymal cells. These cells differentiate into stromal keratocytes and synthesize the secondary, mature stroma, a structure in which each orthogonal layer is many collagen fibrils thick.

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Jiang, Honghui, Yuanyuan Kong, Lili Song, Jing Liu, and Zhihong Wang. "A Thermostable Type I Collagen from Swim Bladder of Silver Carp (Hypophthalmichthys molitrix)." Marine Drugs 21, no. 5 (April 28, 2023): 280. http://dx.doi.org/10.3390/md21050280.

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As a major component of the extracellular matrix, collagen has been used as a biomaterial for many purposes including tissue engineering. Commercial collagen derived from mammals is associated with a risk of prion diseases and religious restrictions, while fish-derived collagen can avoid such issues. In addition, fish-derived collagen is widely available and low-cost; however, it often suffers from poor thermal stability, which limits its biomedical application. In this study, collagen with a high thermal stability was successfully extracted from the swim bladder of silver carp (Hypophthalmichthys molitrix) (SCC). The results demonstrated that it was a type I collagen with high purity and well-preserved triple-helix structure. Amino acid composition assay showed that the amounts of threonine, methionine, isoleucine and phenylalanine in the collagen of swim bladder of silver carp were higher than those of bovine pericardium. After adding Tris solution, swim-bladder-derived collagen could form fine and dense collagen fibers. In particular, SCC exhibited a higher thermal denaturation temperature (40.08 °C) compared with collagens from the swim bladder of grass carp (Ctenopharyngodon idellus) (GCC, 34.40 °C), bovine pericardium (BPC, 34.47 °C) and mouse tail (MTC, 37.11 °C). Furthermore, SCC also showed DPPH radical scavenging ability and reducing power. These results indicate that SCC presents a promising alternative source of mammalian collagen for pharmaceutical and biomedical applications.

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Kalyuzhnaya, L. I., M. O. Sokolova, and V. E. Chernov. "Reservation of the Most Important Structural Components of the Human Umbilical Cord after Decellularization as a Stage in the Manufacture of a Highly Regenerative Wound Dressing." Biotekhnologiya 37, no. 5 (2021): 61–65. http://dx.doi.org/10.21519/0234-2758-2021-37-5-61-65.

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Abstract-To create the basis for the wound covering, we have developed a tissue-engineered cell-free structure from a highly regenerative homologous biomaterial of the human umbilical cord. The construct retains dermal-like structural components and therefore can stimulate the repair of skin imperfections. The composition and structure of the tissue-engineered scaffold from the human umbilical cord was evaluated by microscopic analysis; porosity was revealed, which promotes cell recruitment. Collagens and glycosaminoglycans form the basis of the tissue-engineered umbilical cord scaffold, which provides the physiological and adhesive properties of the final product. Thin long collagen fibers constitute a dense network, similar to the dermal extracellular matrix. The retention of type IV collagen and laminin is important for basement membrane formation and cell attachment. Key words: bioscaffold, matrix, scaffold, decellularization, tissue engineering, wound covering

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Rujchanarong, Denys, Alison T. Stopeck, Christina Preece, Ren Sun, Pavani Chalasani, Sean Brown, Ji D. Bai, et al. "Abstract 782: Correlation between collagen peptides and physical features of fibrosis in breast tissue from women at increased risk of cancer." Cancer Research 84, no. 6_Supplement (March 22, 2024): 782. http://dx.doi.org/10.1158/1538-7445.am2024-782.

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Abstract Breast cancer risk increases significantly in women who maintain higher radiologically dense breast tissue as they age. However, the mechanisms that underlie this association remain poorly understood, especially in postmenopausal women. A predominant contributor to dense breasts and differences between women is the relative amount of fibrillar collagens. Experimental models suggest that changes in collagen properties such as fiber alignment and stiffness promote local stromal fibrosis, which we hypothesize may contribute to the relationship between breast density, aging, and tumorigenesis. Normal breast biopsy samples from the contralateral, healthy breast of 32 postmenopausal breast cancer patients participating in a clinical trial for drug effect on breast density were examined and scored for areas of fibrosis and analyzed using second harmonic generation microscopy (SHG) and mass spectrometry proteomics. Our aim was to identify areas of fibrosis and relate the severity of focal fibrosis to the physical properties and peptide composition of collagen fibers. Using GraphPad Prism, we conducted one-way ANOVA and Kruskal-Wallis tests and post-hoc multiple comparison tests. H&E-stained breast tissue samples were scored according to percent fibrosis. The minimum and maximum percent fibrosis were 5% and 100%, respectively, with a median of 60% (95% CI: 97.06%). Out of 31 people, 16 had a higher fibrosis score than the median. Consistent with pathologic scoring of the presence and extent of fibrosis, fiber counts were significantly lower in tissue with lower fibrosis scores than samples with more highly scored fibrosis (p-value <0.001). Distance to the nearest fiber was greater in samples with < 20% fibrosis, whereas greater alignment to the nearest fiber was observed in higher fibrosis percentages. At the molecular level, 22 peptides demonstrated a strong correlation with percent fibrosis (spearman r ≥ 60), of which 13 peptides were statistically significant (p-value <0.0001). The putatively identified peptides belong to type I, III, IV and VI collagens. Fiber length and straightness, but not fiber width, were higher in tissues with greater percent fibrosis. Significant correlations were identified between collagen physical features and peptides: two distinct peptides correlated with collagen fiber length and straightness while 20 peptides correlated with fiber width. These putative peptides belong to types I, III, IV and V collagens with ~70% of the peptides containing at least one hydroxyproline modification. This study is the first to explore the link between focal fibrosis and collagen-associated peptides in healthy breast tissue of high-risk postmenopausal women. These findings provide novel insights on stromal collagens associated with fibrotic changes in normal at-risk breast tissue that may act in tissue susceptibility to tumor formation. Citation Format: Denys Rujchanarong, Alison T. Stopeck, Christina Preece, Ren Sun, Pavani Chalasani, Sean Brown, Ji D. Bai, Heather Jensen Smith, Sungyong You, Peggi M. Angel, Patricia Thompson. Correlation between collagen peptides and physical features of fibrosis in breast tissue from women at increased risk of cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 782.

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Giraud Guille, Marie Madeleine, Christophe Helary, Sylvain Vigier, and Nadine Nassif. "Dense fibrillar collagen matrices for tissue repair." Soft Matter 6, no. 20 (2010): 4963. http://dx.doi.org/10.1039/c0sm00260g.

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Chicatun, Florencia, Claudio E. Pedraza, Chiara E. Ghezzi, Benedetto Marelli, Mari T. Kaartinen, Marc D. McKee, and Showan N. Nazhat. "Osteoid-Mimicking Dense Collagen/Chitosan Hybrid Gels." Biomacromolecules 12, no. 8 (August 8, 2011): 2946–56. http://dx.doi.org/10.1021/bm200528z.

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Traub, W., L. Zylberberg, V. de Buffrenil, T. Arad, and S. Weiner. "Collagen-apatite complexes in very dense bones." Acta Crystallographica Section A Foundations of Crystallography 58, s1 (August 6, 2002): c172. http://dx.doi.org/10.1107/s0108767302091900.

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Wu, Jiulin, Xiaoban Guo, Hui Liu, and Li Chen. "Isolation and Comparative Study on the Characterization of Guanidine Hydrochloride Soluble Collagen and Pepsin Soluble Collagen from the Body of Surf Clam Shell (Coelomactra antiquata)." Foods 8, no. 1 (January 1, 2019): 11. http://dx.doi.org/10.3390/foods8010011.

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The aim of this study was to characterize the collagens from the body of surf clam shell (Coelomactra antiquata). Guanidine hydrochloride and pepsin were used to extract collagens. Guanidine hydrochloride soluble collagen (GSC) and pepsin soluble collagen (PSC) were separately isolated from the body of surf clam shell. Results showed that the moisture, protein, carbohydrate, and ash contents of the body of surf clam shell were 82.46%, 11.56%, 3.05%, and 2.38%, respectively, but the fat content was only 0.55%. The yields were 0.59% for GSC and 3.78% for PSC. Both GSC and PSC were composed of α1 and α2 chains and a β chain, however, GSC and PSC showed distinct differences from each other and the type I collagen from grass carp muscle on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). GSC and PSC contained glycine as the major amino acid and had imino acid of 150 and 155 residues/1000 residues, respectively. Fourier transform infrared spectroscopy (FTIR) spectra of GSC and PSC revealed the presence of a triple helix. The GSC appeared to have a dense sheet-like film linked by random-coiled filaments and PSC had fine globular filaments under scanning electron microscopy (SEM). The maximum transition temperature (Tmax) of GSC and PSC was 33.05 °C and 31.33 °C, respectively. These results provide valuable scientific information for the texture study and development of surf clam shell or other bivalve mollusks.

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Joliat, Thomas, Joel Bernstein, J. S. Cho, Marc Krug, T. Fujiyoshi, Jerome Seyer, X. J. Ye, and T. J. Yoo. "Antibodies against a 30 Kilodalton Cochlear Protein and Type II and IX Collagens in the Serum of Patients with Inner Ear Diseases." Annals of Otology, Rhinology & Laryngology 101, no. 12 (December 1992): 1000–1006. http://dx.doi.org/10.1177/000348949210101207.

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Collagen molecules are major extracellular matrix proteins involved in the development and support of delicate auditory sensory organs. Type II collagen is widely distributed within inner ear tissues, while type IX is found only within the labyrinthine membrane and dense fibers of the tectorial membrane. Antibody specific for type II collagen has been shown to be elevated in some patients with hearing loss due to several presumably autoimmune illnesses (including Meniere's disease, otosclerosis, chronic progressive sensorineural hearing loss, and relapsing polychondritis). Purified human type II and LX collagens and an extract of human cochlear tissue were subjected to isolation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and transferred to nitrocellulose. The sera of 21 patients with inner ear disease were examined for the presence of anticollagen and anticochlear antibodies; the sera were used to probe Western blots of purified human collagens U, LX, and XI, and cochlear protein extract with peroxidase-conjugated goat anti human polyvalent immunoglobulin as the second antibody. Anti-type II collagen antibodies were seen in 12 of 21 (57%) patients, while 13 of 21 (62%) had anti-type IX antibodies detectable by Western blot. A previously unreported 30 kd (probably noncollagen) protein was found by SDS-PAGE of human cochlear tissue extracts, with 3 patients, all with Meniere's disease, having antibody activity to this protein detected by Western blot. Anti-type II and anti-type LX antibodies were found in a high percentage of patients with Meniere's disease, otosclerosis, and strial atrophy. Six patients (29%), and all control patients, had no detectable antibodies to these proteins by our assay.

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Gobeaux, F., G. Mosser, A. Anglo, P. Panine, P. Davidson, M. M. Giraud-Guille, and E. Belamie. "Fibrillogenesis in Dense Collagen Solutions: A Physicochemical Study." Journal of Molecular Biology 376, no. 5 (March 2008): 1509–22. http://dx.doi.org/10.1016/j.jmb.2007.12.047.

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Grant, D. S., C. P. Leblond, H. K. Kleinman, S. Inoue, and J. R. Hassell. "The incubation of laminin, collagen IV, and heparan sulfate proteoglycan at 35 degrees C yields basement membrane-like structures." Journal of Cell Biology 108, no. 4 (April 1, 1989): 1567–74. http://dx.doi.org/10.1083/jcb.108.4.1567.

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Three basement membrane components, laminin, collagen IV, and heparan sulfate proteoglycan, were mixed and incubated at 35 degrees C for 1 h, during which a precipitate formed. Centrifugation yielded a pellet which was fixed in either potassium permanganate for ultrastructural studies, or in formaldehyde for Lowicryl embedding and immunolabeling with protein A-gold or anti-rabbit immunoglobulin-gold. Three types of structures were observed and called types A, B, and C. Type B consisted of 30-50-nm-wide strips that were dispersed or associated into a honeycomb-like pattern, but showed no similarity with basement membranes. Immunolabeling revealed that type B strips only contained heparan sulfate proteoglycan. The structure was attributed to self-assembly of this proteoglycan. Type A consisted of irregular strands of material that usually accumulated into semisolid groups. Like basement membrane, the strands contained laminin, collagen IV, and heparan sulfate proteoglycan, and, at high magnification, they appeared as a three-dimensional network of cord-like elements whose thickness averaged approximately 3 nm. But, unlike the neatly layered basement membranes, the type A strands were arranged in a random, disorderly manner. Type C structures were convoluted sheets composed of a uniform, dense, central layer which exhibited a few extensions on both surfaces and was similar in appearance and thickness to the lamina densa of basement membranes. Immunolabeling showed that laminin, collagen IV, and proteoglycan were colocalized in the type C sheets. At high magnification, the sheets appeared as a three-dimensional network of cords averaging approximately 3 nm. Hence, the organization, composition, and ultrastructure of type C sheets made them similar to the lamina densa of authentic basement membranes.

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Egorikhina, Marfa N., Ludmila L. Semenycheva, Victoria O. Chasova, Irina I. Bronnikova, Yulia P. Rubtsova, Evgeniy A. Zakharychev, and Diana Ya Aleynik. "Changes in the Molecular Characteristics of Bovine and Marine Collagen in the Presence of Proteolytic Enzymes as a Stage Used in Scaffold Formation." Marine Drugs 19, no. 9 (September 2, 2021): 502. http://dx.doi.org/10.3390/md19090502.

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Biopolymers, in particular collagen and fibrinogen, are the leading materials for use in tissue engineering. When developing technology for scaffold formation, it is important to understand the properties of the source materials as well as the mechanisms that determine the formation of the scaffold structures. Both factors influence the properties of scaffolds to a great extent. Our present work aimed to identify the features of the molecular characteristics of collagens of different species origin and the changes they undergo during the enzymatic hydrolysis used for the process of scaffold formation. For this study, we used the methods of gel-penetrating chromatography, dynamic light scattering, reading IR spectra, and scanning electron microscopy. It was found that cod collagen (CC) and bovine collagen (BC) have different initial molecular weight parameters, and that, during hydrolysis, the majority of either type of protein is hydrolyzed by the proteolytic enzymes within the first minute. The differently sourced collagen samples were also hydrolyzed with the formation of two low molecular fractions: Mw ~ 10 kDa and ~20 kDa. In the case of CC, the microstructure of the final scaffolds contained denser, closely spaced fibrillar areas, while the BC-sourced scaffolds had narrow, short fibrils composed of unbound fibers of hydrolyzed collagen in their structure.

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Pacheco, Ricardo B., Marina Salvarani Tonoli, and Marisa Masumi Beppu. "Membranes of Chitosan and Collagen-Type 1 for Biomineralization/Ostheogenesis." Key Engineering Materials 587 (November 2013): 222–26. http://dx.doi.org/10.4028/www.scientific.net/kem.587.222.

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The main objective of this work was to produce membranes of chitosan and collagen type I and check their ability to undergo “in vitro” calcification. The membranes of chitosan-collagen blends were characterized by TGA, infra-red spectroscopy and DSC. Samples of dense and porous membranes were immersed in solution SBF (Simulated Body Fluid) in order to verify their “in vitro” calcification. The membranes were observed by SEM. The production of chitosan-collagen membranes is possible, in dense and porous versions. We can conclude that the blend is less resistant to high temperatures, in comparison to pristine chitosan membranes shown in literature. Through the initial assays of calcification, we observe that it is possible to induce the calcium deposition on a chitosan-collagen membrane, as seen by SEM. Microscopy of fracture surfaces showed fibril structures, probably formed by collagen.

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Artym, Vira V. "Dense fibrillar collagen is a master activator of invadopodia." Molecular & Cellular Oncology 3, no. 3 (April 11, 2016): e1035476. http://dx.doi.org/10.1080/23723556.2015.1035476.

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Picaut, Lise, Léa Trichet, Olivier Ronsin, Bernard Haye, Isabelle Génois, Tristan Baumberger, and Gervaise Mosser. "Pure dense collagen threads from extrusion to fibrillogenesis stability." Biomedical Physics & Engineering Express 4, no. 3 (March 8, 2018): 035008. http://dx.doi.org/10.1088/2057-1976/aaab78.

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Helary, C., L. Ovtracht, G. Godeau, B. Coulomb, and MM Giraud Guille. "Myofibroblasts in Dense Model Collagen Matrices: Migration, Proliferation, Apoptosis." Wound Repair and Regeneration 13, no. 1 (January 17, 2005): A20. http://dx.doi.org/10.1111/j.1067-1927.2005.130117l.x.

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Zitnay, Jared L., Shawn P. Reese, Garvin Tran, Niloofar Farhang, Robert D. Bowles, and Jeffrey A. Weiss. "Fabrication of dense anisotropic collagen scaffolds using biaxial compression." Acta Biomaterialia 65 (January 2018): 76–87. http://dx.doi.org/10.1016/j.actbio.2017.11.017.

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Tidu, Aurélien, Djida Ghoubay-Benallaoua, Claire Teulon, Sophie Asnacios, Kate Grieve, François Portier, Marie-Claire Schanne-Klein, Vincent Borderie, and Gervaise Mosser. "Highly concentrated collagen solutions leading to transparent scaffolds of controlled three-dimensional organizations for corneal epithelial cell colonization." Biomaterials Science 6, no. 6 (2018): 1492–502. http://dx.doi.org/10.1039/c7bm01163f.

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James-Bhasin, Mark, Peter Siegel, and Showan Nazhat. "A Three-Dimensional Dense Collagen Hydrogel to Model Cancer Cell/Osteoblast Interactions." Journal of Functional Biomaterials 9, no. 4 (December 12, 2018): 72. http://dx.doi.org/10.3390/jfb9040072.

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No curative treatment options exist once breast cancer metastasizes to bone. This is due, in part, to an incomplete understanding of how osteolytic cancers interact with bone. Presented here is a novel approach to study the interactions between triple negative breast cancer cells and osteoblasts within a 3D collagenous environment. More specifically, a dense collagen hydrogel was employed to model interactions between MDA-MB-231 breast cancer cells and MC3T3-E1 pre-osteoblasts. Co-cultures with these two cell types, or MDA-MB-231-derived conditioned medium applied to MC3T3-E1 cells, were established in the context of plastically compressed dense collagen gel matrices. Importantly, breast cancer-derived conditioned medium or the establishment of breast cancer/osteoblast co-cultures did not negatively influence MC3T3-E1 cell viability. The inclusion of either conditioned medium or the presence of MDA-MB-231 cells resulted in impaired MC3T3-E1 differentiation into osteoblasts, which coincided with reduced osteoblast-mediated mineralization. The results presented here demonstrate that dense collagen gels provide a model environment to examine the effect of osteolytic breast cancer cells on osteoblast differentiation and subsequent mineralization of the collagen scaffold.

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Keene, D. R., L. Y. Sakai, R. E. Burgeson, and H. P. Bächinger. "Direct visualization of IgM antibodies bound to tissue antigens using a monoclonal anti-type III collagen IgM as a model system." Journal of Histochemistry & Cytochemistry 35, no. 3 (March 1987): 311–18. http://dx.doi.org/10.1177/35.3.3546481.

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A mouse monoclonal IgM antibody directed against human Type III collagen was utilized to immunolocalize Type III collagen by transmission and scanning electron microscopy without the use of an electron-dense conjugate. Because bound IgM can be directly visualized, primary or secondary antibody conjugates, such as ferritin, HRP, colloidal gold, etc., are unnecessary in this method. Immunolocalization to Type III collagen in the matrix of human skin and to fibrils formed in vitro using only IgM antibody reveals uninterrupted IgM binding which exactly matches the banding period of the collagen fibrils. In contrast, colloidal gold-conjugated secondary antibody complexes directed against primary IgM binding sites reveal less precise labeling. The data suggest that direct visualization of primary monoclonal IgM antibodies may be useful in a wide variety of highly specific ultrastructural immunolocalization studies without requiring the use of electron-dense conjugates.

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Portier, François, Claire Teulon, Agnieszka Nowacka-Perrin, Flavien Guenneau, Marie-Claire Schanne-Klein, and Gervaise Mosser. "Stabilization of Collagen Fibrils by Gelatin Addition: A Study of Collagen/Gelatin Dense Phases." Langmuir 33, no. 45 (October 31, 2017): 12916–25. http://dx.doi.org/10.1021/acs.langmuir.7b02142.

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35

Troka, Ildi, Gabriele Griffanti, Lucie Canaff, Geoffrey Hendy, David Goltzman, and Showan Nazhat. "Effect of Menin Deletion in Early Osteoblast Lineage on the Mineralization of an In Vitro 3D Osteoid-like Dense Collagen Gel Matrix." Biomimetics 7, no. 3 (July 22, 2022): 101. http://dx.doi.org/10.3390/biomimetics7030101.

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Bone has a complex microenvironment formed by an extracellular matrix (ECM) composed mainly of mineralized type I collagen fibres. Bone ECM regulates signaling pathways important in the differentiation of osteoblast-lineage cells, necessary for bone mineralization and in preserving tissue architecture. Compared to conventional 2D cell cultures, 3D in vitro models may better mimic bone ECM and provide an environment to support osteoblastic differentiation. In this study, a biomimetic 3D osteoid-like dense collagen gel model was used to investigate the role of the nuclear protein menin plays in osteoblastic differentiation and matrix mineralization. Previous in vitro and in vivo studies have shown that when expressed at later stages of osteoblastic differentiation, menin modulates osteoblastogenesis and regulates bone mass in adult mice. To investigate the role of menin when expressed at earlier stages of the osteoblastic lineage, conditional knockout mice in which the Men1 gene is specifically deleted early (i.e., at the level of the pluripotent mesenchymal stem cell lineage), where generated and primary calvarial osteoblasts were cultured in plastically compressed dense collagen gels for 21 days. The proliferation, morphology and differentiation of isolated seeded primary calvarial osteoblasts from knockout (Prx1-Cre; Men1f/f) mice were compared to those isolated from wild-type (Men1f/f) mice. Primary calvarial osteoblasts from knockout and wild-type mice did not show differences in terms of proliferation. However, in comparison to wild-type cells, primary osteoblast cells derived from knockout mice demonstrated deficient mineralization capabilities and an altered gene expression profile when cultured in 3D dense collagen gels. In summary, these findings indicate that when expressed at earlier stages of osteoblast differentiation, menin is important in maintaining matrix mineralization in 3D dense collagen gel matrices, in vitro.

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Rousselle, P., G. P. Lunstrum, D. R. Keene, and R. E. Burgeson. "Kalinin: an epithelium-specific basement membrane adhesion molecule that is a component of anchoring filaments." Journal of Cell Biology 114, no. 3 (August 1, 1991): 567–76. http://dx.doi.org/10.1083/jcb.114.3.567.

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Basal keratinocytes attach to the underlying dermal stroma through an ultrastructurally unique and complex basement membrane zone. Electron-dense plaques along the basal surface plasma membrane, termed hemidesmosomes, appear to attach directly to the lamina densa of the basement membrane through fine strands, called anchoring filaments. The lamina densa is secured to the stroma through a complex of type VII collagen containing anchoring fibrils and anchoring plaques. We have identified what we believe is a novel antigen unique to this tissue region. The mAbs to this antigen localize to the anchoring filaments, just below the basal-dense plate of the hemidesmosomes. In cell culture, the antigen is deposited upon the culture substate by growing and migrating human keratinocytes. Addition of mAb to the cultures causes the cells to round and detach, but does not impair them metabolically. Skin fragments incubated with antibody extensively de-epithelialize. These findings strongly suggest that this antigen is intimately involved in attachment of keratinocytes to the basement membrane. This antigen was isolated from keratinocyte cultures by immunoaffinity chromatography. Two molecules are observed. The most intact species contains three nonidentical chains, 165, 155, and 140 kD linked by interchain disulfide bonds. The second and more abundant species contains the 165- and 140-kD chains, but the 155-kD chain has been proteolytically cleaved to 105 kD. Likewise, two rotary-shadowed images are observed. The larger of the two, presumably corresponding to the most intact form, appears as an asymmetric 107-nm-long rod, with a single globule at one end and two smaller globules at the other. The more abundant species, presumably the proteolytically cleaved form, lacks the distal small globule. We propose the name "kalinin" for this new molecule.

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37

Krishnaswamy, Venkat Raghavan, Rachita Lakra, and Purna Sai Korrapati. "Keloid collagen–cell interactions: structural and functional perspective." RSC Adv. 4, no. 45 (2014): 23642–48. http://dx.doi.org/10.1039/c4ra01995d.

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38

Alekseeva, T., E. Hadjipanayi, EA Abou Neel, and RA Brown. "Engineering stable topography in dense bio-mimetic 3D collagen scaffolds." European Cells and Materials 23 (January 29, 2012): 28–40. http://dx.doi.org/10.22203/ecm.v023a03.

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39

Gobeaux, F., E. Belamie, G. Mosser, P. Davidson, P. Panine, and M. M. Giraud-Guille. "Cooperative Ordering of Collagen Triple Helices in the Dense State." Langmuir 23, no. 11 (May 2007): 6411–17. http://dx.doi.org/10.1021/la070093z.

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40

Coyac, B. R., F. Chicatun, B. Hoac, V. Nelea, C. Chaussain, S. N. Nazhat, and M. D. McKee. "Mineralization of Dense Collagen Hydrogel Scaffolds by Human Pulp Cells." Journal of Dental Research 92, no. 7 (April 30, 2013): 648–54. http://dx.doi.org/10.1177/0022034513488599.

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41

Qu, Haibo, Zengmin Xia, David A. Knecht, and Mei Wei. "Synthesis of Dense Collagen/Apatite Composites Using a Biomimetic Method." Journal of the American Ceramic Society 91, no. 10 (October 2008): 3211–15. http://dx.doi.org/10.1111/j.1551-2916.2008.02634.x.

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42

Mosser, Gervaise, Anny Anglo, Christophe Helary, Yves Bouligand, and Marie-Madeleine Giraud-Guille. "Dense tissue-like collagen matrices formed in cell-free conditions." Matrix Biology 25, no. 1 (January 2006): 3–13. http://dx.doi.org/10.1016/j.matbio.2005.09.002.

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43

Marelli, Benedetto, Chiara E. Ghezzi, Jake E. Barralet, Aldo R. Boccaccini, and Showan N. Nazhat. "Three-Dimensional Mineralization of Dense Nanofibrillar Collagen−Bioglass Hybrid Scaffolds." Biomacromolecules 11, no. 6 (June 14, 2010): 1470–79. http://dx.doi.org/10.1021/bm1001087.

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44

Helary, C., B. Rodrigues-Sanchez, S. Vigier, and M. M. Giraud Guille. "Dense fibrillar collagen matrices to analyse extracellular matrix receptor function." Pathologie Biologie 60, no. 1 (February 2012): 7–14. http://dx.doi.org/10.1016/j.patbio.2011.10.007.

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45

Griffanti, Gabriele, and Showan N. Nazhat. "Dense fibrillar collagen-based hydrogels as functional osteoid-mimicking scaffolds." International Materials Reviews 65, no. 8 (March 18, 2020): 502–21. http://dx.doi.org/10.1080/09506608.2020.1735828.

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46

Griffanti, Gabriele, Ehsan Rezabeigi, Jingjing Li, Monzur Murshed, and Showan N. Nazhat. "Rapid Biofabrication of Printable Dense Collagen Bioinks of Tunable Properties." Advanced Functional Materials 30, no. 4 (November 11, 2019): 1903874. http://dx.doi.org/10.1002/adfm.201903874.

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RAMTANI, SALAH, YOSHIYUKI TAKAHASHI-IÑIGUEZ, CHRISTOPHE HELARY, DIDIER GEIGER, and MARIE MADELEINE GIRAUD GUILLE. "MECHANICAL BEHAVIOR UNDER UNCONFINED COMPRESSION LOADINGS OF DENSE FIBRILLAR COLLAGEN MATRICES MIMETIC OF LIVING TISSUES." Journal of Mechanics in Medicine and Biology 10, no. 01 (March 2010): 35–55. http://dx.doi.org/10.1142/s0219519410003290.

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Bio-artificial tissues are being developed as replacements for damaged biologic tissues and their mechanical properties are critical for load-bearing applications. Reconstituted dense three-dimensional (3D) fibrillar collagen matrices are promising materials for tissue engineering, at the light of their interaction with fibroblasts.1,2 The mechanical properties of these fibrillar collagen matrices are now being characterized under unconfined compression loading for various strain rates and collagen concentrations. The data were compared to those obtained in the same conditions with a biological tissue, the rat dermis. The results show a very sensitive behavior to both the displacement rate, typical of biological soft tissues, and the collagen concentration varying between 5 and 40 mg/ml. The link between the mechanical properties and the microscopic structure of the collagen scaffolds show an increasing viscoelastic modulus with respect to the fibril density. It is found that the matrices at 5 mg/ml and the dorsal rat skin (DRS) exhibit similar stress–strain response when submitted to the same external unconfined compression load. Such results highlight the interest of these matrices as potential tissue substitutes.

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48

Okano, Takahisa, and Takehisa Matsuda. "Tissue Engineered Skeletal Muscle: Preparation of Highly Dense, Highly Oriented Hybrid Muscular Tissues." Cell Transplantation 7, no. 1 (January 1998): 71–82. http://dx.doi.org/10.1177/096368979800700110.

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We prepared highly dense, highly oriented hybrid muscular tissues that are composed of C2C12 cells (skeletal muscle myoblast cell line) and type I collagen. A cold mixture of C2C12 cells suspended in DMEM and type I collagen solution was poured into capillary tube molds of two different sizes (inner diameters; 0.90 and 0.53 mm, respectively). One end of each mold was sealed. Upon centrifugation (1000 rpm, 5 min) and subsequent thermal gelation, a rod-shaped gel was obtained. It was cultured in an agarose gel-coated dish for 7 days (first for 3 days in a growth medium and then for 4 days in a differentiation medium), during which time it shrank to become a highly dense tissue. Small-diameter rod-shaped, highly dense cellular assemblages with multinucleated myotubes were formed and only few necrotic cells at the core of the tissue were observed. On the other hand, a ring-shaped tissue prepared using a specially devised agarose gel mold was subjected to cyclic stretching at 60 rpm, resulting in the formation of a highly dense, highly oriented hybrid muscular tissue in which both densely accumulated cells and collagen fiber bundles tended to be aligned in the direction of stretching. The hybrid muscular tissues that were prepared using via sequential procedures of a centrifugal cell packing method and a mechanical stress-loading method became closer to native muscular tissues in terms of cell density and orientation.

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Wingender, Brian, Yongliang Ni, Yifan Zhang, Curtis Taylor, and Laurie Gower. "Hierarchical Characterization and Nanomechanical Assessment of Biomimetic Scaffolds Mimicking Lamellar Bone via Atomic Force Microscopy Cantilever-Based Nanoindentation." Materials 11, no. 7 (July 22, 2018): 1257. http://dx.doi.org/10.3390/ma11071257.

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The hierarchical structure of bone and intrinsic material properties of its two primary constituents, carbonated apatite and fibrillar collagen, when being synergistically organized into an interpenetrating hard-soft composite, contribute to its excellent mechanical properties. Lamellar bone is the predominant structural motif in mammalian hard tissues; therefore, we believe the fabrication of a collagen/apatite composite with a hierarchical structure that emulates bone, consisting of a dense lamellar microstructure and a mineralized collagen fibril nanostructure, is an important first step toward the goal of regenerative bone tissue engineering. In this work, we exploit the liquid crystalline properties of collagen to fabricate dense matrices that assemble with cholesteric organization. The matrices were crosslinked via carbodiimide chemistry to improve mechanical properties, and are subsequently mineralized via the polymer-induced liquid-precursor (PILP) process to promote intrafibrillar mineralization. Neither the crosslinking procedure nor the mineralization affected the cholesteric collagen microstructures; notably, there was a positive trend toward higher stiffness with increasing crosslink density when measured by cantilever-based atomic force microscopy (AFM) nanoindentation. In the dry state, the average moduli of moderately (X51; 4.8 ± 4.3 GPa) and highly (X76; 7.8 ± 6.7 GPa) crosslinked PILP-mineralized liquid crystalline collagen (LCC) scaffolds were higher than the average modulus of bovine bone (5.5 ± 5.6 GPa).

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Tsiper, Maria V., and Peter D. Yurchenco. "Laminin assembles into separate basement membrane and fibrillar matrices in Schwann cells." Journal of Cell Science 115, no. 5 (March 1, 2002): 1005–15. http://dx.doi.org/10.1242/jcs.115.5.1005.

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Laminins are important for Schwann cell basement membrane assembly and axonal function. In this study, we found that exogenous laminin-1, like neuromuscular laminins-2/4, formed two distinct extracellular matrices on Schwann cell surfaces, each facilitated by laminin polymerization. Assembly of one, a densely-distributed reticular matrix, was accompanied by a redistribution of cell-surface dystroglycan and cytoskeletal utrophin into matrix-receptor-cytoskeletal complexes. The other, a fibrillar matrix,accumulated in separate zones associated with pre-existing β1-integrin arrays. The laminin-1 fragment E3 (LG-modules 4-5), which binds dystroglycan and heparin, inhibited reticular-matrix formation. By contrast,β1-integrin blocking antibody (Ha2/5) prevented fibrillar assembly. Ultrastructural analysis revealed that laminin treatment induced the formation of a linear electron-dense extracellular matrix (lamina densa)separated from plasma membrane by a narrow lucent zone (lamina lucida). This structure was considerably reduced with non-polymerizing laminin, fully blocked by E3, and unaffected by Ha2/5. Although it formed in the absence of type IV collagen, it was nonetheless able to incorporate this collagen. Finally, cell competency to bind laminin and form a basement membrane was passage-dependent. We postulate that laminin induces the assembly of a basement membrane on competent cell surfaces probably mediated by anchorage through LG 4-5. Upon binding, laminin interacts with dystroglycan,mobilizes utrophin, and assembles a `nascent' basement membrane, independent of integrin, that is completed by incorporation of type IV collagen. However,the fibrillar β1-integrin dependent matrix is unlikely to be precursor to basement membrane.

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Journal articles on the topic 'Collagène dense'

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