Heparin-Conjugated Fibrin as an Injectable System for Sustained Delivery of Bone Morphogenetic Protein-2

Abstract

Long-term release of bone morphogenetic protein-2 (BMP-2) can promote bone regeneration. We developed an injectable system for long-term delivery of BMP-2 by covalently conjugating heparin to fibrinogen. The heparin-conjugated fibrinogen formed an injectable, heparin-conjugated fibrin (HCF) gel when mixed with thrombin. HCF released 89.4 +/- 3.8% of the loaded BMP-2 for 13 days, whereas normal fibrin released 83.7 +/- 7.6% for the initial 3 days. BMP-2 released from HCF significantly increased alkaline phosphatase activity of cultured osteoblasts, whereas BMP-2 released from normal fibrin did not do so, indicating that BMP-2 released from HCF is bioactive and suggesting that long-term delivery of BMP-2 is advantageous over short-term delivery for bone regeneration. HCF, BMP-2-loaded HCF, and BMP-2-loaded normal fibrin containing free heparin were contained in polyester cylindrical tubes and implanted into the hind limb muscle pockets of rats for 8 weeks. Soft X-ray radiography, computed tomography, histomorphometry, calcium assay, and western blot analysis showed that BMP-2-loaded HCF yielded the most extensive bone formation among the groups. Since HCF can deliver BMP-2 over a long term, is an injectable system, and is made of clinically benign materials, this system would have advantages for clinical applications to regenerate bone.

Experimental and Computational Investigation of the Effect of Hydrophobicity on Aggregation and Osteoinductive Potential of BMP-2-Derived Peptide in a Hydrogel Matrix

“…3 For example, the probability of an adverse side effect with the use of BMP-2 in spine fusion may be as high as 40%. 3 Encapsulation or grafting of nano-and microspheres is used to localize the protein to the site of regeneration and reduce diffusion [4][5][6] ; however, tumor formation and inflammatory response persist in some patients. 7 The side effects of BMP-2 protein stem from its ability to promote cell migration and vascularization and its involvement in tumor angiogenesis.…”

Enhanced skin wound healing by a sustained release of growth factors contained in platelet-rich plasma

“…Various heparin-conjugated biomaterials have been utilized as a GF delivery vehicle (Jeon et al, 2006;Thomopoulos et al, 2010;Yang et al, 2010aYang et al, , 2010b by mimicking the physiological function of heparin sulfate (HS), which is abundant in the extracellular matrix (ECM). During healing, GFs are detached from and HS boosts the effect of the GFs (Schultz and Wysocki, 2009).…”

“…# P ＜ 0.01 compared to any group. HCF can provide superior tissue regeneration properties to fibrin-based carriers by releasing bone morphogenic protein-2 (Yang et al, 2010b) and FGF2 (Yang et al, 2010a) for long time periods. In the present study, we have adopted HCF as a PRP carrier system and used it to make comparisons with other carrier systems both in vitro and in vivo.…”

“…We first examined the release kinetics of GFs contained in PRP from HCF and fibrin-based carriers. Among the GFs contained in PRP, release of PDGF-BB, VEGF, and FGF2 was evaluated since these GFs can bind to heparin in HCF (Yang et al, 2010a(Yang et al, , 2010b and are known to stimulate angiogenesis (Yang et al, 2010a), which promotes skin wound healing (Tonnesen et al, 2000). Activities of GFs released from the carriers were evaluated by determining the growth of human dermal fibroblasts (HDFs) cultured in the presence of GF delivery systems.…”

Enhancement of Human Peripheral Blood Mononuclear Cell Transplantation-Mediated Bone Formation

“…The animals were sacrificed at 8 fuged on a Ficoll-Paque density gradient (specific gravweeks after implantation. The time point was chosen beity = 1.077, Amersham Biosciences, Arlington Heights, cause previous studies showed excellent bone formation IL, USA) for 30 min at 230 × g. PBMNCs were isolated at this time point (19,35). Ten samples were taken per from the buffy coat layer between the Ficoll-Paque regroup.…”