Elastin-derived scaffolding associated or not with bone morphogenetic protein (BMP) or hydroxyapatite (HA) in the repair process of metaphyseal bone defects.

Marcelo De Azevedo E Sousa Munhoz,Marcelo Rodrigues Da Cunha,Murilo Priori Alcalde,Eduardo Gomes Machado,Renato De Moraes,Guinea Brasil Camargo Cardoso,Rogerio Leone Buchaim,Daniela Vieira Buchaim,Fernando Bento Cunha,Ana Maria De Guzzi Plepis,Karina Torres Pomini,Arnaldo Rodrigues Santos Junior,Virginia Da Conceição Amaro Martins,Marco Antonio Hungaro Duarte,Gianpaolo Papaccio

doi:10.1371/journal.pone.0231112

Abstract

Tissue engineering represents a promising alternative for reconstructive surgical procedures especially for the repair of bone defects that do not regenerate spontaneously. The present study aimed to evaluate the effects of the elastin matrix (E24/50 and E96/37) incorporated with hydroxyapatite (HA) or morphogenetic protein (BMP) on the bone repair process in the distal metaphysis of rat femur. The groups were: control group (CG), hydrolyzed elastin matrix at 50°C/24h (E24/50), E24/50 + HA (E24/50/HA), E24/50 + BMP (E24/50/BMP), hydrolyzed elastin matrix at 37°C/96h (E96/37), E96/37 + HA (E96/37/HA), E96/37 + BMP (E96/37/BMP). Macroscopic and radiographic analyses showed longitudinal integrity of the femur in all groups without fractures or bone deformities. Microtomographically, all groups demonstrated partial closure by mineralized tissue except for the E96/37/HA group with hyperdense thin bridge formation interconnecting the edges of the ruptured cortical. Histologically, there was no complete cortical recovery in any group, but partial closure with trabecular bone. In defects filled with biomaterials, no chronic inflammatory response or foreign body type was observed. The mean volume of new bone formed was statistically significant higher in the E96/37/HA and E24/50 groups (71.28 ± 4.26 and 66.40 ± 3.69, respectively) than all the others. In the confocal analysis, it was observed that all groups presented new bone markings formed during the experimental period, being less evident in the CG group. Von Kossa staining revealed intense calcium deposits distributed in all groups. Qualitative analysis of collagen fibers under polarized light showed a predominance of red-orange birefringence in the newly regenerated bone with no difference between groups. It was concluded that the E24/50 and E96/37/HA groups promoted, with greater speed, the bone repair process in the distal metaphysis of rat femur.

Highlights

In recent decades, the search for therapeutic strategies has been increasing in order to promote the innate regenerative potential of deteriorating tissues and restore morphological and functional integrity [1]
The present study aimed to evaluate the effects of the elastin matrix (E24/50 and E96/37) incorporated with hydroxyapatite (HA) or morphogenetic protein (BMP) on the bone repair process in the distal metaphysis of rat femur
The DSC curves did not show a transition in the temperature range studied, suggesting that there is no presence of collagen in the matrices, due to the long period of exposure of biological tissue, 96h to alkaline hydrolysis at a temperature of 37 ̊C or even to the short interval, 24h, but with high temperature, 50 ̊C

Summary

Introduction

The search for therapeutic strategies has been increasing in order to promote the innate regenerative potential of deteriorating tissues and restore morphological and functional integrity [1]. Several types of materials have been developed as substitutes for autogenous grafts due to their well-established limitations, such as the possibility of donor site morbidity, risk of infection and limited amount of material available [3]. In this context, synthetic bone substitutes have become potential materials for clinical applications because they have good biocompatibility with surrounding tissues and chemical stability in body fluid [4]. Synthetic hydroxyapatite (HA) ceramics are often used in orthopedic and craniofacial repairs because they form a mechanically stable interface and have controlled and interconnected pore size, which favors the conduction of osteoprogenitor cells in situ [1]. Natural polymers, including the auricular cartilage-derived elastin matrix, referred to as third-generation biomaterials, have aroused interest in providing specific interactions with cellular integrins and direct cell proliferation and differentiation, as well as synthesis and organization of the extracellular matrix [5] In addition, elastin microfibrils, the essential protein structure of the extracellular matrix, are interconnected by crosslinking which gives the material the characteristic of a three-dimensional porous framework [6]

Methods

Results

Conclusion