Regeneración ósea en fémur de conejo mediante el implante de una matriz bioactiva basada en recombinámeros de tipo elastina (ELRs)"

IBÁÑEZ-FONSECA, D.J. ; COLETTA, D; L.R. MISSANA, ; G.E. BUMAGUIN,; E.J. VITELLI,; F. GARBINO, ; F. ZABALZA, ; M.V. JAMMAL,; S. FELDMAN,; J.C. RODRÍGUEZ-CABELLO,; F.J. ARIAS, ; M. ALONSO

Madrid

Congreso; XXXIII Congreso Anual de la Sociedad Española de Ingeniería Biomédica (CASEIB2015).; 2015

The aim of bone regeneration using tissue engineering is to promote de novo bone regeneration by response from biodegradable matrix. Our object was to analyze the ability from an elastin-like recombinant (ELRs) matrix implanted in femoral injure in rabbits, it would promote bone tissue regeneration. ELRs were obtained using recombinant DNA strategies by Escherichia coli (strain BL21 (DE3, NOVAGEN) transformed with an expression vector derived from pET-25(+) plasmid, which contains ELRs coding genes. Plasmids were genetically designed in order to achieve bioactivity adding the following sequences: (a) RGD for cellular adhesion, (b) BMP-2 (Bone morphogenetic protein-2), and (c) an elastase recognition dominium. In addition to this, changing some amino acids allowed us to obtain a hydrogel soluble at -4°C but that transforms to a gel at room temperature. We have previously developed a medial distal femoral defect (6 mm diameter) in New Zealand female rabbits. Seven rabbits with femoral defects received 100 ul of ELRs, that immediately jellified into the injurie. The experimental animals showed immediate recovery without observed clinical alterations in contrast to controls (temperature, general conditions, feeding habits, mobility of the injured foot). All these aspects were controlled up to 3 month after implant, when animals were euthanized. The exact implant area was suited by X-ray. Tomographic analysis (Toshiba Alexion equipment, with 16 detectors, algorithm of bone reconstruction, 3D) showed cortical defect repair at the medial cortical from distal metaphysis-epiphysis area. One case show one mm diameter defect. The others demonstrate full repair. Samples were decalcified by modified Morse Solution and processed in histological routine manners. Serial sections (5u) were stained by H&E and studied by optical microscopy. The results showed a thick new bone formed in ?mosaic pattern?, with many vascular canals surrounding remains of implanted matrix. The degraded matrix shows granular mineralized areas covered by osteoblast-like cells. In the surrounding zone some trabeculae were lined by two or more osteoblasts lines. Osteocytes were arresting. These are original results by in vivo bone tissue formation from a biodegradable matrix obtained using DNA recombinant technique and probably potentiated by the in situ effect of BMP-2.