New Novel Bone Fusion Using TAT-BMP Hydrogel in Rat Model
Authors: Jahng T. A. , Lee S. E. , Noh I. S. , Yook J. I. 
Published: June 2012

Introduction

Despite bone fusion using BMP is promising, its clinical applications are limited due to high cost and unwanted ectopic bony fusion. Furthermore, its processing is complicated and low yield. Recently, new method of BMP producing has been developed using TAT protein domain, which can facilitate the passage of high molecular protein into the cell. Thus BMP precursor with TAT can pass the cell membrane and convert into BMP after chemical degradation. It can secret as BMP itself and activate intrinsic BMP production. Basic animal studies showed rapid diffusion of TAT-BMP in spite of carrier material. For stable release of TAT-BMP, Chitosan hydrogel was made with TAT-BMP and applied to rat model.

Materials and Methods

Under intraperitoneal anesthesia, the rat thoracolumbar spine was exposed as usual spinal procedure, 1–2 spinous processes were removed and TAT-BMP hydrogel (total 1 cc in volume) or Biopad (calcium bisphosphte) was implanted and operative wound was closed. Total 12 rats randomly assign for TAT-BMP hydrogel (8 rats) and Biopad (4 rats). Animals were survived for 2 months and sacrificed for radiologic and histological examination. Simple X-ray and micro-CT were taken, and histological examination (H & E staining) was done.

Results

On gross examination, all TAT-BMP hydrogel groups showed palpable mass, and it confirmed with histological finding. Unfortunately, mature bone formation was not even due to short survival period. There is insufficient release of hydrogel in some cases, but there were no ectopic bone formation. On micro-CT, bone trabeculation was visible, but not enough like mature bone.

Conclusion

Although it was preliminary results, bone fusion using TAT-BMP hydrogel was promising. Further studies using bigger animal and titration of hydrogel with longer survival period are mandatory for clinical implementation. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared Aono A, Hazama M, Notoya K, et al. Potent ectopic bone-inducing activity of bone morphogenetic protein-4/7 heterodimer. Biochemical and Biophysical Research Communication 1995;210(3): 670–677 Aspenberg P, Turek T. BMP-2 for intramuscular bone induction: effect in squirrel monkeys is dependent on implantation site. Acta Orthopaedica Scandavica 1996;67(1): 3–6 Cross KJ, Wharton SA, Skehel JJ, Wiley DC, Steinhauer DA. Studies on influenza hemagglutinin fusion peptide mutants generated by reverse genetics. EMBO Journal 2002;20(16):4432–4442. 2001 De Crescenzo G, Grothe S, Zwaagstra J, Tsang M, O'Connor-McCourt MD. Real-time monitoring of the interactions of transforming growth factor-beta (TGF-beta ) isoforms with latency-associated protein and the ectodomains of the TGF-beta type II and III receptors reveals different kinetic models and stoichiometries of binding. Journal of Biological Chemistry 2001;276(32): 29632–29643 Dijke P, Miyazono K, Heldin CH. Signaling via hetero-oligomeric complexes of type I and type II serine/threonine kinase receptors. Current Opinion in Cell Biology 1996;8(2):139–145 Fittipaldi A, Ferrari A, Zoppe M, et al. Cell membrane lipid rafts mediate caveolar endocytosis of HIV-1 Tat fusion proteins. Journal of Biological Chemistry 2003;278(36): 34141–34149 Frankel AD, Pabo CO: Cellular uptake of the tat protein from human immunodeficiency virus. Cell 1988;55:1189–1193 Futaki S, Goto S, Suzuki T, Nakase I, Sugiura Y. Structural variety of membrane permeable peptides. Current Protein and Peptide Science 2003;4(2):87–96 Giraudo CG, Maccioni HJ. Ganglioside glycosyltransferases organize in distinct multienzyme complexes in CHO-K1 cells. Journal of Biological Chemistry 2003;278(41): 40262–40271 Green M, Loewenstein PM. Autonomous functional domains of chemically synthesized human immunodeficiency virus tat trans-activator protein. Cell 1988;55:1179–1188 Gregory KE, Ono RN, Charbonneau NL, et al. The prodomain of BMP-7 targets the BMP-7 complex to the extracellular matrix. Journal of Biological Chemistry 2005;280(30): 27970–27980 Groeneveld EH, Burger EH. Bone morphogenetic proteins in human bone regeneration. European Journal of Endocrinology 2000;142(1):9–21 Itoh H, Ebara S, Kamimura M, et al. Experimental spinal fusion with use of recombinant human bone morphogenetic protein 2. Spine 1999;24:1402–1405 Hawiger J. Noninvasive intracellular delivery of functional peptides and proteins. Current Opinion in Chemical Biology 1999;3(1): 89–94 Leifert JA, Whitton JL. Translocatory proteins” and “protein transduction domains: a critical analysis of their biological effects and the underlying mechanisms. Molecular Therapy 2003;8:13–20 Liu F, Ventura F, Doody J, Massague J. Human type II receptor for bone morphogenetic proteins (BMPs): extension of the two-kinase receptor model to the BMPs. Molecular Cellular Biology 1995;15(7): 3479–3486 Li RH, Wozney JM. Delivering on the promise of bone morphogenetic proteins. Trends in Biotechnology 2001;19(7): 255–265 Massague J, Andres J, Attisano L, et al. TGF-beta receptors. Molecular Reproduction and Development 1992;32(2): 99–104 Michiue H, Tomizawa K, Wei FY, et al. The NH2 terminus of influenza virus haemagglutinin-2 subunit peptides enhances the antitumor potency of polyarginine-mediated p53 protein transduction. Journal of Biological Chemistry 2005;280(9): 8285–8289 Nagahara H, Vocero-Akbani AM, Snyder EL, et al. Transduction of full-length TAT fusion proteins into mammalian cells: TAT-p27Kip1 induces cell migration. Nature Medicine 1998;4(12): 1449–1452 Neilson EG. Setting a trap for tissue fibrosis. Nature Medicine 2005;11(4): 373–374 Reddi AH. Bone morphogenetic proteins: from basic science to clinical applications. Journal of Bone Joint Surgery American Volume 2001;83-A, Suppl 1(Pt 1):S1-S6