Slow and continuous application of human recombinant bone morphogenetic protein via biodegradable poly(lactide-co-glycolide) foamspheres

Weber, Franz E.; Eyrich, Gerold; Grätz, Klaus W.; Maly, Friedrich E.; Sailer, Hermann F.

doi:10.1054/ijom.2001.0154

Cited by 68 publications

(53 citation statements)

References 19 publications

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“…Specimens were radiographed, x-ray image photographed, scanned, and then assessed for radioopacity within a standard 8-mm-diameter circle superimposed over the defect site by using NIH IMAGE software (1.62f). Samples were histologically processed according to a previously described method (24).…”

Section: Determination Of Degradation Kinetics Of Soluble Peptides Bymentioning

confidence: 99%

Synthetic matrix metalloproteinase-sensitive hydrogels for the conduction of tissue regeneration: Engineering cell-invasion characteristics

Lütolf

Lauer‐Fields

Schmoekel

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

1,354

1,261

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Synthetic hydrogels have been molecularly engineered to mimic the invasive characteristics of native provisional extracellular matrices: a combination of integrin-binding sites and substrates for matrix metalloproteinases (MMP) was required to render the networks degradable and invasive by cells via cell-secreted MMPs. Degradation of gels was engineered starting from a characterization of the degradation kinetics (kcat and Km) of synthetic MMP substrates in the soluble form and after crosslinking into a 3D hydrogel network. Primary human fibroblasts were demonstrated to proteolytically invade these networks, a process that depended on MMP substrate activity, adhesion ligand concentration, and network crosslinking density. Gels used to deliver recombinant human bone morphogenetic protein-2 to the site of critical defects in rat cranium were completely infiltrated by cells and remodeled into bony tissue within 4 wk at a dose of 5 g per defect. Bone regeneration was also shown to depend on the proteolytic sensitivity of the matrices. These hydrogels may be useful in tissue engineering and cell biology as alternatives for naturally occurring extracellular matrix-derived materials such as fibrin or collagen. extracellular matrix ͉ biomaterials ͉ proteolytic degradation A dvances in the field of tissue engineering are connected to the performance of biomaterials that help in guiding tissue formation or regeneration. Design principles in biomaterials have typically been influenced by the function of the extracellular matrix (ECM). Because the ECM has been demonstrated to play a key role in signal transduction (1-3), the development of materials that can specifically and molecularly interact with cells has become an emerging area of research (4, 5). The regulation of cell behavior through receptor-mediated adhesion [e.g., by functionalizing materials with integrin-binding oligopeptides (6, 7)] and by growth factors (8) has thus been targeted.We and others have been focusing on the development of synthetic materials that are targeted to assist tissue regeneration (9-11). Placed at the site of a defect, such materials should actively and temporarily participate in the regeneration process by providing a platform on which cell-triggered remodeling could occur. Consequently, these matrices must display some key characteristics of the provisional ECM. One of the critical initial functions of the fibrin-rich network that fills tissue defects after trauma, almost regardless of the injury site, lies in its ability to foster the invasion of inflammatory cells. These cells then initiate the remodeling process by partially degrading the matrix and by secreting molecular signals for attraction and differentiation of other cell types such as fibroblasts that build up new ECM (12). Because the provisional ECM presents itself in such situations often as a biophysical barrier to these cells, invasion and remodeling depend on the action of cell-secreted proteases enabling cell migration by clearing of a path (13,14). Thereby, matrix met...

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Section: Determination Of Degradation Kinetics Of Soluble Peptides Bymentioning

confidence: 99%

Synthetic matrix metalloproteinase-sensitive hydrogels for the conduction of tissue regeneration: Engineering cell-invasion characteristics

Lütolf

Lauer‐Fields

Schmoekel

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

1,354

1,261

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“…Cells were then cultured for 14 d with either CM or OM, alone or further supplemented with either 50 or 500 ng/mL rhBMP-2 (produced in bacteria as previously described (Weber et al, 2002), hereafter referred to as own-produced, or produced in mammalian CHO cells by R&D Systems) and analysed by reverse transcriptase real time polymerase chain reaction (RT-rt-PCR). Cells were then treated with lysis buffer (Qiagen, http://www.qiagen.com) enriched with 1/100 (V/V) β-mercaptoethanol (Sigma-Aldrich).…”

Section: Frequency Of Clonogenic Cellsmentioning

confidence: 99%

Intraoperative engineering of osteogenic grafts combining freshly harvested, human adipose-derived cells and physiological doses of bone morphogenetic protein-2

Mehrkens

Saxer

Güven

et al. 2012

eCM

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Engineered osteogenic constructs for bone repair typically involve complex and costly processes for cell expansion. Adipose tissue includes mesenchymal precursors in large amounts, in principle allowing for an intraoperative production of osteogenic grafts and their immediate implantation. However, stromal vascular fraction (SVF) cells from adipose tissue were reported to require a molecular trigger to differentiate into functional osteoblasts. The present study tested whether physiological doses of recombinant human BMP-2 (rhBMP-2) could induce freshly harvested human SVF cells to generate ectopic bone tissue. Enzymatically dissociated SVF cells from 7 healthy donors (1 x 10(6) or 4 x 10(6)) were immediately embedded in a fibrin gel with or without 250 ng rhBMP-2, mixed with porous silicated calcium-phosphate granules (Actifuse(®), Apatech) (final construct size: 0.1 cm(3)) and implanted ectopically for eight weeks in nude mice. In the presence of rhBMP-2, SVF cells not only supported but directly contributed to the formation of bone ossicles, which were not observed in control cell-free, rhBMP-2 loaded implants. In vitro analysis indicated that rhBMP-2 did not involve an increase in the percentage of SVF cells recruited to the osteogenic lineage, but rather induced a stimulation of the osteoblastic differentiation of the committed progenitors. These findings confirm the feasibility of generating fully osteogenic grafts using an easily accessible autologous cell source and low amounts of rhBMP-2, in a timing compatible with an intraoperative schedule. The study warrants further investigation at an orthotopic site of implantation, where the delivery of rhBMP-2 could be bypassed thanks to the properties of the local milieu.

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“…Non-glycosylated rhBMP-2 was expressed in E.coli and refolded as previously described [33]. Glycosylated rhBMP-2 was obtained from Genetics Institute Inc., Massachusetts, USA.…”

Section: General Preparationsmentioning

confidence: 99%

Analysis of hydrolyzable polyethylene glycol hydrogels and deproteinized bone mineral as delivery systems for glycosylated and non-glycosylated bone morphogenetic protein-2

Hänseler

Jung

et al. 2012

Acta Biomaterialia

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Bone morphogenetic proteins (BMP), in particular BMP-2, are the growth factors primarily responsible for osteoinduction. A knowledge of interactions between bone substitute materials and growth factor variants is crucial to designing bone substitutes with an ideal release profile. Here we compare glycosylated and non-glycosylated recombinant human bone morphogenetic protein-2 (rhBMP-2) either incorporated into a hydrolyzable polyethylene glycol (PEG) hydrogel developed as a slow release system or adsorbed to a deproteinized bovine bone matrix (DBBM), a clinically well-established bone substitute material. rhBMP-2 loaded materials were immersed in cell culture medium and rhBMP-2 concentration profiles in the supernatant were determined by an enzyme-linked immunosorbent assay. The corresponding biological activities were assessed in vitro by alkaline phosphatase activity assay. We show a strong affinity of rhBMP-2 for DBBM and reduced biological activity after its release from PEG hydrogels. Glycosylated rhBMP-2 was significantly less affected by the hydrogel and interacted significantly more strongly with DBBM than non-glycosylated rhBMP-2. We therefore question the combination of PEG hydrogels with DBBM as a rhBMP-2 delivery system over DBBM alone, since rhBMP-2 released from the hydrogel will be trapped by DBBM. Moreover, our results suggest that glycosylated rhBMP-2 is favorable in combination with PEG hydrogels, since its activity is better preserved, whereas in combination with DBBM non-glycosylated rhBMP-2 is favorable, benefiting from an initially higher concentration of free rhBMP-2. The corresponding biological activities were assessed in vitro by an alkaline phosphatase activity assay. We show a strong affinity of rhBMP-2 to DBBM and a reduced biological activity after its release from PEG hydrogels. Glycosylated rhBMP-2 was significantly less affected by hydrogels and interacted significantly stronger with DBBM than non-glycosylated rhBMP-2. We therefore question the combination of PEG hydrogels with DBBM as a rhBMP-2 delivery system over DBBM alone since rhBMP-2 released from the hydrogel will be trapped by DBBM.Moreover, our results suggest that glycosylated rhBMP-2 is favorable in combination with PEG hydrogels since its activity is better preserved. Whereas in combination with DBBM, non-glycosylated rhBMP-2 is favorable in order to benefit from an initially higher concentration of free rhBMP-2.

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Slow and continuous application of human recombinant bone morphogenetic protein via biodegradable poly(lactide-co-glycolide) foamspheres

Cited by 68 publications

References 19 publications

Synthetic matrix metalloproteinase-sensitive hydrogels for the conduction of tissue regeneration: Engineering cell-invasion characteristics

Synthetic matrix metalloproteinase-sensitive hydrogels for the conduction of tissue regeneration: Engineering cell-invasion characteristics

Intraoperative engineering of osteogenic grafts combining freshly harvested, human adipose-derived cells and physiological doses of bone morphogenetic protein-2

Analysis of hydrolyzable polyethylene glycol hydrogels and deproteinized bone mineral as delivery systems for glycosylated and non-glycosylated bone morphogenetic protein-2

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