Elastin Calcification in the Rat Subdermal Model Is Accompanied by Up-Regulation of Degradative and Osteogenic Cellular Responses

Lee, Jeoung Soo; Basalyga, Dina M.; Simionescu, Anca A.; Isenburg, Jason C.; Simionescu, Dan T.; Vyavahare, Narendra R.

doi:10.2353/ajpath.2006.050338

Cited by 73 publications

(56 citation statements)

References 56 publications

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“…We have extensively studied mechanisms of elastin calcification and have shown that matrix degrading enzymes such as MMPs are involved in elastin calcification [12,48]. In this study, an initial inflammatory response (macrophage infiltration) seen at 7 days was reduced by 28 days.…”

Section: Discussionmentioning

confidence: 65%

In vivo cellular repopulation of tubular elastin scaffolds mediated by basic fibroblast growth factor

2007

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In vivo tissue engineering has been explored as a method to repopulate scaffolds with autologous cells to create a functional, living, and non-immunogenic tissue substitute. In this study, we describe an approach to in vivo cellular repopulation of a tissue-derived tubular elastin scaffold. Pure elastin scaffolds were prepared from porcine carotid arteries (elastin tubes). Elastin tubes were filled with agarose gel containing basic fibroblast growth factor (bFGF) to allow sustained release of growth factor. These tubes were implanted in subdermal pouches in adult rats. The elastin tubes with growth factor had significantly more cell infiltration at 28 days than those without growth factor. Immunohistochemical staining indicated that most of these cells were fibroblasts, of which a few were activated fibroblasts (myofibroblasts). Microvasculature was also observed within the scaffolds. Macrophage infiltration was seen at 7 days, which diminished by 28 days of implantation. None of the elastin tubes with bFGF calcified. These results demonstrated that the sustained release of bFGF brings about repopulation of elastin scaffolds in vivo while inhibiting calcification. Results showing myofibroblast infiltration and vascularization are encouraging since such an in vivo implantation technique could be used for autologous cell repopulation of elastin scaffolds for vascular graft applications.

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Section: Discussionmentioning

confidence: 65%

In vivo cellular repopulation of tubular elastin scaffolds mediated by basic fibroblast growth factor

2007

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“…At day 21, harvested constructs were ground into powder in liquid nitrogen, extracted in RIPA buffer containing protease inhibitors (Invitrogen, Carlsbad, CA), and then assayed for total protein content using a BCA assay kit (Thermo Scientific). 19 Volumes equivalent to 3 mg of protein were loaded under reduced conditions into 4%-12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gel for LOX analysis and 10% SDS-PAGE gel for MMP analysis, along with a prestained molecular weight ladder (Invitrogen). The gels were then transferred wet onto polyvinylidene fluoride membranes.…”

Section: Western Blotting For Lox and Mmps-2 And -9mentioning

confidence: 99%

Induced Elastic Matrix Deposition Within Three-Dimensional Collagen Scaffolds

Venkataraman

Ramamurthi²

2011

Tissue Engineering Part A

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The structural stability of a cyclically distending elastic artery and the healthy functioning of vascular smooth muscle cells (SMCs) within are maintained by the presence of an intact elastic matrix and its principal protein, elastin. The accelerated degradation of the elastic matrix, which occurs in several vascular diseases, coupled with the poor ability of adult SMCs to regenerate lost elastin, can therefore adversely impact vascular homeostasis. Similarly, efforts to tissue engineer elastic matrix structures are constrained by our inability to induce adult cells to synthesize tropoelastin precursors and to crosslink them into architectural mimics of native elastic matrices, especially within engineered constructs where SMCs/fibroblasts primarily deposit collagen in abundance. In this study, we have shown that transforming growth factor-beta1 (TGF-b1) and hyaluronan oligomers (HA-o) synergistically enhance elastic matrix deposition by adult rat aortic SMCs (RASMCs) seeded within nonelastogenic, statically loaded three-dimensional gels, composed of nonelastogenic type-I collagen. While there was no substantial increase in production of tropoelastin within experimental cases compared to the nonadditive control cultures over 3 weeks, we observed significant increases in matrix elastin deposition; soluble matrix elastin in constructs that received the lowest doses of TGF-b1 with respective doses of HA-o, and insoluble matrix at the highest doses that corresponded with elevated lysyl-oxidase protein quantities. However, despite elastogenic induction, overall matrix yields remained poor in all experimental cases. At all provided doses, the factors reduced the production of matrix metalloproteinases (MMP)-9, especially the active enzyme, though MMP-2 levels were lowered only in constructs cultured with the higher doses of TGF-b1. Immuno-fluorescence showed elastic fibers within the collagen constructs to be discontinuous, except at the edges of the constructs. Von Kossa staining revealed no calcific deposits in any of the cases. This study confirms the benefits of utilizing TGF-b1 and HA-o in inducing matrix elastin synthesis by adult RASMCs over nonadditive controls, within a collagenous environment, that is not inherently conducive to elastogenesis.

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“…Limited attention has been devoted to discerning the activities of enzymes on polymer degradation [18,19] and many other related issues have yet to be explored. It was previously reported that the activities of various capsule-borne enzymes were elevated in a rat subdermal model two weeks after material implantation [20]. However, abnormal expressions of many oxidative and hydrolytic enzymes are associated with diseases.…”

Section: Assessment Of Enzyme Activitiesmentioning

confidence: 99%

The biodegradability of electrospun Dextran/PLGA scaffold in a fibroblast/macrophage co-culture

2008

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Fibroblast and macrophage are two dominant cell types respond cooperatively to degrade implanted biomaterials. Using an electrospun Dextran/Poly-lactide-co-glycolide (PLGA) scaffold as a model, an in vitro fibroblast/macrophage co-culture system was developed to investigate the degradability of implantable biodegradable materials. SEM showed that both fibroblasts and macrophages were able to degrade the scaffold, separately or cooperatively. Under the synergistic coordination of macrophages and fibroblasts, scaffolds showed faster degradation rate than their counterparts incubated with a single type of cells as well as in PBS or cell culture medium. Lysozyme, non-specific esterase (NSE), gelatinase, hyaluronidase-1 and α-glucosidase were upregulated in the presence of the scaffold, suggesting their roles in the cell-mediated scaffold degradation. In addition, the expressions of cell surface receptors CD204 and Toll like receptor 4 (TLR4) were elevated one week after cell seeding, implying that these receptors might be involved in scaffold degradation. The results of in vivo subdermal implantation of the scaffold further confirmed the biodegradability of the Dextran/PLGA scaffold. The fibroblast/macrophage co-culture model adequately mimicked the in vivo environment and could be further developed into an in vitro tool for initial biomaterial evaluation.

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Elastin Calcification in the Rat Subdermal Model Is Accompanied by Up-Regulation of Degradative and Osteogenic Cellular Responses

Cited by 73 publications

References 56 publications

In vivo cellular repopulation of tubular elastin scaffolds mediated by basic fibroblast growth factor

In vivo cellular repopulation of tubular elastin scaffolds mediated by basic fibroblast growth factor

Induced Elastic Matrix Deposition Within Three-Dimensional Collagen Scaffolds

The biodegradability of electrospun Dextran/PLGA scaffold in a fibroblast/macrophage co-culture

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