3 edition of Effects of thrombin on the migration of primary osteogenic cells through fibrin-filled scaffolds. found in the catalog.
Advisers:John Davies; Molly Shoichet.Thesis (Ph.D.)--University of Toronto, 2004.Electronic version licensed for access by U. of T. users.Source: Dissertation Abstracts International, Volume: 65-10, Section: B, page: 5270.
|The Physical Object|
|Pagination||xvi, 93 p. :|
|Number of Pages||58|
This thesis is directed towards a bone tissue engineering strategy that would maximize osteogenic cell invasion into the bony defect. Through culturing primary bone marrow cells under osteogenic culture conditions on PLGA 3-D scaffolds and examining the interface with SEM, TEM and EDS, a candidate PLGA scaffold was demonstrated to support direct bone contact. In an attempt to stimulate maximal invasion of host bone tissue in vivo, fibrin, the natural migration matrix of the blood clot, was investigated as a candidate scaffold pore-filling matrix. Scaffolds filled with fibrin, polymerized with either a low thrombin concentration (LTF) or a high thrombin concentration (HTF), were implanted into drill hole defects in the distal femurs of rats. The area of bone formed at 2, 5 and 11 days post implantation was determined histomorphometrically. After 5 days, scaffolds filled with HTF had 2.2 +/- 1.2% of their available area occupied by bone compared to 8.9 +/- 3.0% for empty scaffolds (p = 0.045, n = 3--4), but no statistical difference was found between the empty scaffolds and the scaffolds filled with LTF (p = 0.976, n = 3--4) which had 8.1 +/- 1.4% of their available area occupied by bone. However, after 11 days there was ∼50% less bone formed within the fibrin filled scaffolds compared to the empty scaffolds (p = 0.003, n = 3). Given that the thrombin, used to polymerize the fibrin, can also stimulate cell migration, the role of thrombin in osteogenic cell migration was investigated. It was shown, using a scratch wound assay, that thrombin stimulated a 2.1 +/- 0.7 (p = 0.042, n = 7) fold increase in cell migration and a common motogenic factor, PDGF-BB stimulated a 3.0 +/- 0.4 fold increase (p = 0.004, n = 3). When a modified Boyden chamber assay was combined with a bone nodule assay, primary cells that had migrated in the presence of thrombin formed 50% (p = 0.040, n = 7) more bone nodules compared to the condition without thrombin.This work has shown that the migration of osteogenic cells, through fibrin-filled PLGA scaffolds that support direct bone contact, can be modulated by altering the thrombin concentration present during fibrin polymerization, and that thrombin has the capacity to stimulate the migration of osteoprogenitor cells and increase bone formation by the migrated cells. File Size: 1MB.
also SF microparticles were employed to such scope, increasing the compressive modulus of SF hydrogels over6-folds in a 1:2 matrix:particle mixture, which in turn enhanced the osteogenic performance of MSCs as well as the calcium adsorption Rockwood et al. Flow Cytometric Analysis, Fluorescent Imaging and Cell Sorting Single cell suspension of differentiated cells was prepared as previously described , and evaluated for YFP fluorescence expression and surface proteins using the fluorescent-activated cell-sorting facility FACSCalibur, BD, San Jose, California, U.
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1 Determining optimal concentrations of fibrinogen and thrombin for ES cell viability and differentiation To assess their effect on ES cell growth and differentiation in fibrin scaffolds, various concentrations of fibrinogen and thrombin were tested.; Lin et al. Stem cells: past, present, and future.
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The standard-of-care for burn wounds is the coverage with gauze dressings designed to minimize trauma to the regenerating epidermis and dermis during dressing changes. Additionally, several studies also demonstrate that the components of human plasma i. 2 Fibrin Fibrin is a polymer that is blood-derived and has been shown to be very biocompatible, can be delivered with growth factors, and can form in vivo after injection.
Incubation of osteocytic MLO-Y4 cells with conditioned media CM collected after continuous FFSS increased MAPK-dependent phosphorylation of Cx43.