Fibrovascularization of Intraorbital Hydroxyapatite-Coated Alumina Sphere in Rabbits

Abstract

We investigated the fibrovascular ingrowth and fibrovascular tissue maturation of hydroxyapatitecoated, porous alumina sphere (Alumina sphere) in comparison with the hydroxyapatite sphere (HAp sphere) in rabbits. Alumina spheres and HAp spheres were implanted in the left orbits of 42 New Zealand white rabbits after enucleation. Fibrovascular ingrowth and maturation were graded from 1 to 5 at postoperative 1, 2, 3, 4, 8, 12 and 24 weeks. We defined 4 phases: postoperative 1-2 weeks as phase I, 3-4 weeks as phase II, 8-12 weeks as phase III, and 24 weeks as phase IV. The grade was analyzed at each phases. There was no significant difference in fibrovascular ingrowth and maturation between the two groups at all 4 phases, except phase II at which the Alumina sphere showed significantly lower maturation grade (p<0.05). We concluded that the Alumina sphere is an ideal orbital implant material and an ideal substitute for the HAp sphere in clinical practice.

In vivo vascularization of MSC-loaded porous hydroxyapatite constructs coated with VEGF-functionalized collagen/heparin multilayers

“…However, the long-term release of VEGF that is achieved with protein incorporation significantly enhanced angiogenesis between day 7 and 14, as well as between day 14 and 28, after biomaterial implantation 58 . In Chung’s study, HA orbital implants and HA-coated alumina orbital implants showed no significant difference in fibrovascular ingrowth 59 . Our in vivo experiments demonstrated that the HA scaffolds with MSCs and VEGF-functionalized COL/HEP multilayers had good vascularization.…”

Preparation and comparative study of a new porous polyethylene ocular implant using powder printing technology

“…The crucial factor for porous ocular implants is rapid fibrovascularization as it decreases complications, such as displacement, exposure and prolapse of the implants. 27 High porosity allows a better interaction between the host and the implant, which in turn allows capillary vessel formation to occur earlier. [28][29] Larger pores generally allows faster fibrovascularization, however, less fibrovascular ingrowth occurs in pore sizes greater than 700 mm due to insufficient structural support, fragility increases, due to decreased intensity, and infection risk increases with pore size.…”

Biomaterials for orbital implants and ocular prostheses: Overview and future prospects

“…There was no clinical difference in the socket response between coated or uncoated implants and, histopathologically, fibrovascularization occurred uniformly throughout each implant at 4, 8 and 12 weeks after implantation. Three years later Chung et al [155] investigated the fibrovascular in-growth and fibrovascular tissue maturation of HA-coated porous alumina implants in comparison with HA sphere in enucleated rabbits over a 24-month follow-up and achieved similar conclusions. There was no significant difference between the two groups, except for the 3 th to 4 th week postoperative period, during which the composite sphere showed a significantly lower grade of fibrovascular tissue maturation.…”