Journal articles: 'Dense collagen'

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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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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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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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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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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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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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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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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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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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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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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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Skakle, J. M. S., and R. M. Aspden. "Neutron diffraction studies of collagen in human cancellous bone." Journal of Applied Crystallography 35, no. 4 (July 18, 2002): 506–8. http://dx.doi.org/10.1107/s002188980200972x.

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The interaction between bone mineral and collagen is essential to the formation and function of bone. It is important, therefore, to study collagenin situ,i.e.within the bone mineral. This represents a challenge, particularly as often the area of interest involves cancellous bone which, because it has an open porous structure, is less dense and can be difficult to section finely. The first neutron diffraction experiments on intact cancellous bone have been performed to examine the spacings between collagen molecules and have demonstrated that this is a feasible technique for such a study. A comparison is made with results on cortical bone.

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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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Cheepala, Satish B., Kazumasa Takenaka, Tamara I. Pestina, Carl W. Jackson, and John D. Schuetz. "The Role of ABC Transporter Abcc4 in Platelets Physiologic Function and Its Impact On Collagen Meditated Platelet Aggregation." Blood 120, no. 21 (November 16, 2012): 1063. http://dx.doi.org/10.1182/blood.v120.21.1063.1063.

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Abstract Abstract 1063 Platelet activation is a highly regulated process, and cyclic nucleotide mediated signaling pathways are crucial to effective platelet activation. Vascular injury produces, exposed collagen which binds circulating platelets through the platelet's “collagen” receptor, GPVI, resulting in the activation of guanyly/adenlyl cyclases. These interactions result in the rapid alterations in the cyclic nucleotide concentration inside the platelets leading to activation of protein kinase A and G signaling pathways to modulate platelet function. While, ABCC4 functions as a plasma membrane transporter for cyclic nucleotides its contribution to platelet activation has been obscured because it was reportedly as primarily intracellular in the platelets dense granules. This original report (Jedlitschky, Tirschmann et al. 2004) evaluated ABCC4 localization by immune-fluorescence of platelets attached to collagen coated coverslips. However, attachment via collagen produces platelet activation leading to mobilization and fusion of alpha and dense granules to the plasma membrane, thus under these conditions distinguishing between plasma membrane and dense granules is not possible. We resolved this problem by labeling quiescent platelets with a cell impermeable biotinylating agent (EZ-Link Sulfo-NHS-LC-LC Biotin). Isolation of membrane and internal fraction demonstrated that of over ninety percent of Abcc4 localizes to the plasma membrane. Furthermore, confocal microscopy of platelets stained with specific antibodies against Abcc4 confirmed Abcc4 localization to the plasma membrane. We extended these studies to the Abcc4- knockout (KO) mouse model. The Abcc4- KO mouse does not have any change in the number of platelet or dense granules compared to the wild type mouse. Platelet activation in vivo can be initiated by interaction with collagen through the GPVI receptor that is expressed at the plasma membrane of the platelets. At the molecular level, the initiation of platelet activation by collagen results in an increase in the cyclic nucleotide concentration leading to activation of signaling cascade through protein kinase A or G. Expose of Abcc4-KO platelets to collagen and revealed impaired activation in response to collagen. However, Abcc4-KO platelets activated by either thrombin or ADP (which activate either G-coupled PAR receptors or P2Y12 receptor respectively) shows an aggregation profile almost identical to wildtype platelets, thus indicating the defect in Abcc4 -KO platelet aggregation is specific to the collagen pathway. To understand the basis for the impaired collagen aggregation of Abcc4-KO platelets, we investigated the collagen receptor (GPVI) signaling pathway in Abcc4-KO platelets. Interestingly, in the Abcc4-KO platelets after the platelet activation with collagen, cyclic nucleotide dependent phosphorylation of VASP through protein kinase A or G at Ser-157 or Ser-239 respectively is reduced compared to the wildtype. Notably, Abcc4-KO platelets had reduced GPVI surface expression that correlated with the reduced phosphorylation of VASP after collagen stimulation. The similar, protein levels of Syk and Plcg2, (downstream signaling molecules of GPVI signaling pathway), in the Abcc4 wildtype and KO platelets implies that GPVI expression is the primary defect in Abcc4 deficiency. These results suggest that Abcc4 plays a crucial role in regulating cyclic nucleotides in response to GPVI activation by collagen. These findings suggest ABCC4/Mrp4 loss of function or inhibition (by drugs) may disrupt platelet aggregation under conditions of vascular injury. As, many antiplatelet drugs are potent inhibitors of Abcc4 (e.g., Dipyridamole and Sildenafil) these conclusions have strong implications for not just the development of antiplatelet drugs, but also for further exploring the role of Abcc4 in regulating intracellular nucleotide levels and platelet biology. Disclosures: No relevant conflicts of interest to declare.

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Cheepala, Satish Babu, Kazumasa Takenaka, Tamara I. Pestina, Carl W. Jackson, and Schuetz John. "The Abcc4 Knockout Reveals An Important Role for Abcc4 in Platelet Aggregation." Blood 118, no. 21 (November 18, 2011): 1141. http://dx.doi.org/10.1182/blood.v118.21.1141.1141.

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Abstract Abstract 1141 Cyclic nucleotides have an important role in platelet aggregation and the role of phosphodiesterases in regulating their concentration is well known. Currently it is unknown if plasma membrane cyclic nucleotide export proteins regulate cyclic nucleotide concentrations in platelets. The ATP-binding cassette transporter, ABCC4 functions as a cyclic nucleotide exporter that is highly expressed in platelets. However, its role as a cyclic nucleotide transporter in platelets is unknown, because it was reportedly localized intracellularly in the platelet dense granules. This original report (Jedlitschky, Tirschmann et al. 2004) evaluated ABCC4 localization by immune-fluorescence of platelets after attachment to collagen coated coverslips. However, collagen attachment activates platelets causing mobilization and fusion of alpha and dense granules to the plasma membrane, thus rendering conditions that distinguish between plasma membrane and dense granules almost impossible. To resolve this problem we isolated the platelets under conditions that minimize activation during isolation. Subsequently, these platelets membranes were labeled with the cell impermeable biotinylating agent (EZ-Link Sulfo-NHS-LC-LC Biotin). Analysis of total platelet lysate detected the dense granule marker, P-selectin and Abcc4. However, after precipitation of the plasma membrane with streptavidin-beads, we detected only Abcc4. This indicates Mrp4 is at the plasma membrane. We confirmed Abcc4 localization by confocal microscopy on platelets that were treated with a monoclonal antibody specific to Abcc4. Evidence that Abcc4 regulates cyclic nucleotide levels under basal conditions was then provided by the findings that Abcc4-null platelets have elevated cyclic nucleotides. We further used the Abcc4-null mouse model to explore the role of Abcc4 in platelet biology. The Abcc4-null mouse does not have any change in the platelet or dense granules number compared to the wild type mouse. Platelet activation in vivo can be initiated by interaction with collagen through the GPVI receptor that is expressed at the plasma membrane of the platelets. At the molecular level, the initiation of platelet activation by collagen results in an increase in the cyclic nucleotide concentration and phosphorylation of vasodilator-stimulated phosphoprotein (VASP) which can attenuate aggregation. To determine the Abcc4 role in this process we exposed Abcc4-null platelets to collagen and discovered that these platelets have impaired activation in response to collagen. However, Abcc4-null platelets activated by thrombin or ADP, which activate either G-coupled PAR receptors or P2Y12 receptor respectively, show an aggregation profile almost identical to wildtype platelets, thus indicating the defect in Abcc4-null platelet aggregation is specific to the collagen initiated pathway. To understand the basis for the impaired aggregation of Abcc4-null platelets, we examined VASP phosphorylation after collagen treatment, and discovered that the cyclic nucleotide dependent phosphorylation of VASP (Ser 157) is elevated in the Abcc4-null platelets. These results strongly suggest that Abcc4-null platelets have impaired GPVI activation by collagen due to elevated cyclic nucleotide concentrations. Based on these studies we conclude that Abcc4 plays a critical role in regulating platelet cyclic nucleotide concentrations and its absence or perhaps inhibition (by drugs) impairs the aggregation response to collagen. Because many antiplatelet drugs are potent inhibitors of Abcc4 (e.g., Dipyridamole and Sildenafil) these findings have strong implications for not just the development of antiplatelet drugs, but also for understanding the role of Abcc4 in regulating intracellular nucleotide levels. Jedlitschky, G., K. Tirschmann, et al. (2004). “The nucleotide transporter MRP4 (ABCC4) is highly expressed in human platelets and present in dense granules, indicating a role in mediator storage.” Blood 104(12): 3603–10. This work was supported by NIH and by the American Lebanese Syrian Associated Charities (ALSAC). Disclosures: No relevant conflicts of interest to declare.

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Berger, Martin, David Lutz, Julia Lutz, Jawad Khalil, Ahmed Aburima, Khalid Naseem, and Francisco Rivero. "Alterations in Platelet Alpha-Granule Secretion and Adhesion on Collagen under Flow in Mice Lacking the Atypical Rho GTPase RhoBTB3." Cells 8, no. 2 (February 11, 2019): 149. http://dx.doi.org/10.3390/cells8020149.

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Typical Rho GTPases, such as Rac1, Cdc42, and RhoA, act as molecular switches regulating various aspects of platelet cytoskeleton reorganization. The loss of these enzymes results in reduced platelet functionality. Atypical Rho GTPases of the RhoBTB subfamily are characterized by divergent domain architecture. One family member, RhoBTB3, is expressed in platelets, but its function is unclear. In the present study we examined the role of RhoBTB3 in platelet function using a knockout mouse model. We found the platelet count, size, numbers of both alpha and dense granules, and surface receptor profile in these mice were comparable to wild-type mice. Deletion of Rhobtb3 had no effect on aggregation and dense granule secretion in response to a range of agonists including thrombin, collagen, and adenosine diphosphate (ADP). By contrast, alpha-granule secretion increased in mice lacking RhoBTB3 in response to thrombin, collagen related peptide (CRP) and U46619/ADP. Integrin activation and spreading on fibrinogen and collagen under static conditions were also unimpaired; however, we observed reduced platelet accrual on collagen under flow conditions. These defects did not translate into alterations in tail bleeding time. We conclude that genetic deletion of Rhobtb3 leads to subtle alterations in alpha-granule secretion and adhesion to collagen without significant effects on hemostasis in vivo.

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Song, Xiaoyu, Yuma Nihashi, Masamichi Yamamoto, Daiki Setoyama, Yuya Kunisaki, and Yasuyuki S. Kida. "Exploring the Role of Desmoplastic Physical Stroma in Pancreatic Cancer Progression Using a Three-Dimensional Collagen Matrix Model." Bioengineering 10, no. 12 (December 18, 2023): 1437. http://dx.doi.org/10.3390/bioengineering10121437.

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Pancreatic ductal adenocarcinoma (PDAC) is a refractory tumor with a poor prognosis, and its complex microenvironment is characterized by a fibrous interstitial matrix surrounding PDAC cells. Type I collagen is a major component of this interstitial matrix. Abundant type I collagen promotes its deposition and cross-linking to form a rigid and dense physical barrier, which limits drug penetration and immune cell infiltration and provides drug resistance and metabolic adaptations. In this study, to identify the physical effect of the stroma, type I collagen was used as a 3D matrix to culture Capan-1 cells and generate a 3D PDAC model. Using transcriptome analysis, a link between type I collagen-induced physical effects and the promotion of Capan-1 cell proliferation and migration was determined. Moreover, metabolomic analysis revealed that the physical effect caused a shift in metabolism toward a glycolytic phenotype. In particular, the high expression of proline in the metabolites suggests the ability to maintain Capan-1 cell proliferation under hypoxic and nutrient-depleted conditions. In conclusion, we identified type I collagen-induced physical effects in promoting Capan-1 cells, which cause PDAC progression, providing support for the role of dense stroma in the PDAC microenvironment and identifying a fundamental method for modeling the complex PDAC microenvironment.

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Druzhkova, Irina, Marina Shirmanova, Nadezhda Ignatova, Varvara Dudenkova, Maria Lukina, Elena Zagaynova, Dina Safina, et al. "Expression of EMT-Related Genes in Hybrid E/M Colorectal Cancer Cells Determines Fibroblast Activation and Collagen Remodeling." International Journal of Molecular Sciences 21, no. 21 (October 30, 2020): 8119. http://dx.doi.org/10.3390/ijms21218119.

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Collagen, the main non-cellular component of the extracellular matrix (ECM), is profoundly reorganized during tumorigenesis and has a strong impact on tumor behavior. The main source of collagen in tumors is cancer-associated fibroblasts. Cancer cells can also participate in the synthesis of ECM; however, the contribution of both types of cells to collagen rearrangements during the tumor progression is far from being clear. Here, we investigated the processes of collagen biosynthesis and remodeling in parallel with the transcriptome changes during cancer cells and fibroblasts interactions. Combining immunofluorescence, RNA sequencing, and second harmonic generation microscopy, we have explored the relationships between the ratio of epithelial (E) and mesenchymal (M) components of hybrid E/M cancer cells, their ability to activate fibroblasts, and the contributions of both cell types to collagen remodeling. To this end, we studied (i) co-cultures of colorectal cancer cells and normal fibroblasts in a collagen matrix, (ii) patient-derived cancer-associated fibroblasts, and (iii) mouse xenograft models. We found that the activation of normal fibroblasts that form dense collagen networks consisting of large, highly oriented fibers depends on the difference in E/M ratio in the cancer cells. The more-epithelial cells activate the fibroblasts more strongly, which correlates with a dense and highly ordered collagen structure in tumors in vivo. The more-mesenchymal cells activate the fibroblasts to a lesser degree; on the other hand, this cell line has a higher innate collagen remodeling capacity. Normal fibroblasts activated by cancer cells contribute to the organization of the extracellular matrix in a way that is favorable for migratory potency. At the same time, in co-culture with epithelial cancer cells, the contribution of fibroblasts to the reorganization of ECM is more pronounced. Therefore, one can expect that targeting the ability of epithelial cancer cells to activate normal fibroblasts may provide a new anticancer therapeutic strategy.

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Maiborodin, I. V., S. V. Khomenyuk, T. V. Mikheeva, G. Yu Yarin, V. I. Maiborodina, I. A. Vilgelmi, and A. I. Shevela. "The acceleration of collagen biodegradation after adsorption of mesenchymal multipotent stromal cells in experiment." Translational Medicine 6, no. 5 (November 17, 2019): 55–67. http://dx.doi.org/10.18705/2311-4495-2019-6-5-55-67.

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Background. The scientific literature contents clearly not enough data at interaction of collagen materials with a living organism and about influence of multipotent stromal cells (MSC) on this process. There are controversies about the collagen degradation and the development of foreign body reactions. However, without account these results, it is impossible to estimate the timeframes for complete lysis of such materials, to progress effective methods for the prevention and treatment of developing complications. Objective. To study the features of the collagen-based material degradation after implantation with adsorbed autologous mesenchymal MSC of bone marrow origin (AMMSCBMO) in the experiment. Design and methods. In different times the condition of tissues around the implanted collagen membrane with adsorbed AMMSCBMO was studied by method of light microscopy. Results. The number of vessels and cellular elements in the collagen material implanted without AMMSCBMO increases to 3 weeks and remains at this level until the end of the observation. A distinctive features of the use of collagen membrane with adsorbed AMMSCBMO are increased vascularization and cellular infiltration of the material in the first 2 weeks after surgery. This effect further leads to a more rapid degradation of all implanted collagen, including its more dense parts, but does not prevent the formation of multinuclear macrophages with fused cytoplasm. Conclusion. As a result of more significant vascularization and cellular infiltration caused by AMMSCBMO adsorbed on the surface of the collagen material, to the 4th week the entire implant is full destroyed and absorbed, and dense fibrous connective tissue is formed in its place. For the implantation into the body, one should choose the most homogeneous collagen materials, without areas of different density, as slowly degrading fragments can cause the development of granulomatous inflammation and the failure of the implantation procedure.

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Helary, Christophe, Aicha Abed, Gervaise Mosser, Liliane Louedec, Didier Letourneur, Thibaud Coradin, Marie Madeleine Giraud-Guille, and Anne Meddahi-Pellé. "Evaluation of dense collagen matrices as medicated wound dressing for the treatment of cutaneous chronic wounds." Biomaterials Science 3, no. 2 (2015): 373–82. http://dx.doi.org/10.1039/c4bm00370e.

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Adams, Samuel B., Michael P. Francis, Yas Maghdouri-White, Nardos Sori, and Nathan Kemper. "A Bioengineered Organized Collagen-Based Microfibrous Implant Designed for Tendon Regeneration." Foot & Ankle Orthopaedics 7, no. 1 (January 2022): 2473011421S0006. http://dx.doi.org/10.1177/2473011421s00069.

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Category: Basic Sciences/Biologics; Sports Introduction/Purpose: Tendon healing is a slow and complicated process that results in inferior structural and functional properties compared to healthy tissue. It may be possible to improve outcomes of tendon healing with enhancement of biological repair through the development of tissue engineered medical products (TEMPs). Although many tendons heal with satisfactory outcomes, others do not, leading to pain and additional cost. Current augments for repair lack either native tissue structure or composition, limiting their potential effectiveness. For example, in tendon healing, restoring native organized and dense collagen composition is a primary goal; however, most TEMPs, such as lyophilized collagen or electrospun pure collagen fibers, are mechanically weak and unstable. For optimizing stability and biocompatibility, collagen can be combined with a high-performance co-biopolymer, such as poly(D,L-lactide) (PDLLA). Methods: The purpose of this study was to demonstrate the efficacy of a novel biointegrative construct, composed of type I collagen and PDLLA for Achilles tendon repair. PDLLA is biocompatible, has shown to support cell growth, and degrades to CO2 and H2O in vivo. The electrospun copolymer constructs were post-processed with low-temperature annealing to enhance their porosity and mechanical stability. The constructs were first tested for their ability to absorb blood and platelet-rich-plasma (PRP). Additionally, the constructs were tested in vivo by implantation in a rabbit Achilles tendon injury model by creating a 7 mm midsubstance Achilles defect. For each tendon defect, a copolymer construct was circumferentially wrapped around the defect and sutured into place. Finally, human cadaver testing was performed to assess implant handling and fixation characteristics. Results: Collagen-PDLLA constructs absorbed more than ten times their weight in blood and PRP. Histologically, rabbit tendons showed rapid implant cellularization by 2-8 weeks, along with de novo collagen deposition. By 16 weeks, dense collagenous connective tissue was seen integrating at the tendon-implant interface and throughout the implant. Movin-Bonar scores for the collagen-PDLLA-implanted and sham-operated tendons were identical from 16-72 weeks post-operatively, indicating a return to normal tendon morphology. Overall, surgical application of the collagen-PDLLA constructs demonstrated dense collagenous fibrous connective tissue ingrowth into and around the implant. Moreover, cadaver surgical implantation of the implant in a minimally invasive Achilles tendon repair and arthroscopic rotator cuff repair, allowed easy graft orientation and delivery as well as excellent handleability and suture fixation to the native tendon. Conclusion: Electrospun biointegrative implants were tissue-engineered to enhance cell infiltration for promoting tissue integration and functional remodeling. When implanted in the rabbit Achilles tendon, the implants demonstrated new in situ tissue generation and remodeled into dense, regularly oriented connective tissue at the tendon-implant interface. Collagenous ingrowth may be crucial in tendon protection and significantly progresses towards improving clinical outcomes following tendon injury. Moreover, the implants demonstrated additional clinical utility by absorbing greater than ten times their weight in biologic fluids which demonstrates the potential to combine this novel biointegrative implant with additional fluid based biologic therapies.

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Journal articles on the topic 'Dense collagen'

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