Evaluation of bFGF collagen composite sponge promoting vascular ingrowth in orbital implantation by 99Tcm-MDP scan / 中华实验眼科杂志

Background Intraorbital implantation of coralline porous hydroxyapatite (CHA) is a favorable cosmetic method after enucleation.However,the low degree of vascularizatiou in implant results in implant infection and exposure.Studies showed that a collagen composite sponge treated by basic fibroblast growth factor (bFGF/ collagen composite sponge) can promote angiogenesis.However,whether bFGF/collagen composite sponge improves the vascularization of CHA implants is unclear.Objective This study was to investigate the accelerating effect of bFGF collagen composite sponge on vascularization of orbital implant made of CHA using 99Tcm-methylene diphosphate (MDP) scan.Methods Forty-five New Zealand rabbits were randomly assigned to 3 groups.Evisceration of eyeball was performed on the left eyes of rabbits,and naked CHA,collagen composite sponge wrapped CHA and bFGF/collagen composite sponge wrapped CHA were implanted into the orbit respectively in 3 groups.99Tcm-MDP of 3 mCi was injected in the rabbits via ear vein in 2,4,6,8 and 12 weeks,and the vascular enhancement intensity on implants was observed 3 hours after injection.The ratio of average radioactive count from the area of interest with the same size between the left eyes and the right eyes was calculated.The implants were extracted for histopathological examination in the 12 weeks.Results As the lapse of postoperative time,the inflammation response gradually disappeared and no exposure of implants was seen during the 12-week duration.A similar vascular development strength was found in the area of interest among the 3 groups 2 weeks after surgery.However,the vascular development was significantly enhanced in the left eyes compared the right eyes from 4 to 6 weeks,with the highest intensity in the 8th week in the naked CHA group and collagen composite sponge wrapped CHA group.In the bFGF/ collagen composite sponge wrapped CHA group,the strongest image was in the 6th week after operation.The ratios of average radioactive count between the left eyes and the right eyes were significantly higher in the bFGF/collagen somposite sponge wrapped CHA group compared with the naked CHA group and collagen composite sponge wrapped CHA group (all at P＜0.05),and ratios of average radioactive count of the collagen composite sponge wrapped CHA group was significantly higher than that of the naked CHA group (all at P＜0.05).New blood vessels ingrowed toward the center of the implants through the coralline porous under the optical microscope.Conclusions Both bFGF (20 μg)/collagen composite sponge and collagen composite sponge can accelerate the ingrowth of vessel in the CHA,but the promoting effect of bFGF collagen composite sponge is prominent.

The Effects of Commodified Growth Factor Products on the Fibrovascularization of Porous Polyethylene Orbital Implants

PURPOSE: To investigate the effects of commodified growth factor products used clinically on fibrovascular ingrowth into porous polyethylene orbital implants. METHODS: Porous polyethylene orbital implant sheets (Medpor(R)) soaked with Nepidermin (Easyef(R)), Trafermin (Fiblast(R)), and normal saline were implanted into the backs of 18 Sprague-Dawley rats. The degree of fibrovascular ingrowth as observed using a light microscope was compared 1 and 2 weeks after implantation and was calculated as a percentage of the fibrovascular ingrowth length. RESULTS: One week after implantation, the percentage of fibrovascular ingrowth length was 25.33 +/- 5.43%, 22.56 +/- 5.30%, and 21.78 +/- 4.66% in the Easyef(R)-, Fiblast(R)- and normal saline-soaked groups. The degree of fibrovascularization was higher in the Easyef(R)-soaked group than in the other groups (p = 0.020, 0.012). Two weeks after implantation, the degree of fibrovascularization was 98.33 +/- 5.00%, 100.00 +/- 0.00%, and 95.89 +/- 4.57%, which was significantly higher in the Easyef(R)-, and Fiblast(R)-soaked groups than in normal saline-soaked group (p = 0.019, <0.001). CONCLUSIONS: Commodified growth factor products used in other areas selectively enhanced fibrovascular ingrowth to a greater degree and earlier in ophthalmic plastic and reconstructive surgery.

The Role of Endothelial Progenital Cells and Fibrin on Vascularization and Stability in Orbital Implant

PURPOSE: The effects of endothelial progenitor cells (EPCs) and fibrin on fibrovascular growth into porous polyethylene orbital implants (Medpor(R) sheet) were investigated using stem cells. METHODS: EPCs were separated from human adipose fat tissue for culture. Fluorescence-activated cell sorting (FACS) was used to identify the phenotype and to analyze the purity of EPCs cultivated from human adipose tissue. Processed Medpor(R) sheets were inserted in each quadrant of the subcutaneous fat layer under the dorsal surface of 20 anesthetized athymic nude mice, using sterile methods. Medpor(R) sheets processed with endothelial progenitor cells and fibrin were inserted into the two top quadrants, a Medpor(R) sheet processed with fibrin was inserted in the lower right quadrant, and an unprocessed Medpor(R) sheet was inserted in the lower left quadrant of each mouse. The mice were sacrificed on the seventh day. The adhesiveness and blood vessel formation were quantified by weight and the number of blood cells within the Medpor(R) sheets. Hematoxylin and eosin (H&E) and toluidine blue stains were used to analyze fibrovascular and cell growth within the Medpor(R) sheets. RESULTS: The sheets processed with EPCs and fibrin were heavier and contained more white and red blood cells (p<0.001) than the other sheets. The sheets processed with fibrin alone were heavier (p<0.01) and contained more blood cells (p<0.001) than the unprocessed sheets. The degree of vessel formation and tissue adhesiveness was greatest in the group of Medpor(R) sheets processed with EPCs and fibrin. The sheets processed with fibrin only had greater tissue adhesiveness and fibrovascular proliferation than the unprocessed Medpor(R) sheets. CONCLUSIONS: Endothelial progenitor cells and fibrin applied to Medpor(R) sheets improve fibrovascular proliferation and tissue adhesiveness. When both are applied together, a synergistic effect is seen.

Fibrovascularization of Intraorbital Hydroxyapatite-Coated Alumina Sphere in Rabbits

We investigated the fibrovascular ingrowth and fibrovascular tissue maturation of hydroxyapatite-coated, 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.

Morphological Study of a New Orbital Implant: Hydroxyapatite-Coated Porous Alumina in Rabbit

PURPOSE: We evaluated the morphologic change of the hydroxyapatite(HA)-coated porous alumina as a new orbital implant when it was used in rabbit. METHODS: After evisceration of 18 eyes of 18 New Zealand white rabbits, we implanted 12 mm-diameter-sized HA-coated porous alumina with different pore sizes; 300, 500, and 800 micrometer, and then the implants were extracted back to evaluate their morphologic change according to different time interval; 2, 4, and 12 weeks. RESULTS: Fibrovascularization was noted at periphery of the implant 2 weeks after implantation in all of the three groups, and to the center of the implant 4 and 12 weeks after implantation. This fibrova-scularization was most predominant in 500 micrometerpore-sized group compared to the rest two groups. CONCLUSIONS: HA-coated porous alumina showed similar appearance of fibrovascularization with relatively more affordable price and easy manufacture, compared to the other porous implants.

Usefulness of 99m Tc-MDP Bone Scintigraphy for Assessing Vascular Ingrowth on Hydrox yapatite Ocular Implant

This study was to evaluate the clinical usefulness of 99m Tc-MDP bone scintigraphy for assessing vascular ingrowth into the ocular implants after enucleation and evisceration. Twenty four patients(M:F=7:17, mean age:36), with a coralline hydroxyapatite after uncomplicated enucleation or evisceration surgery were studied. Uptake ratio was also calculated by measuring the implants activity(H)and contralateral orbit activity(N). Grading score and uptake ratio were compared with clinical outcome of vascularization. Additionally, we also analyzed the vascularization status as time lapse between primary surgery and scintigraphic study and surgical methods. The degree of grade and uptake ratio were inversely correlated with vascular ingrowth. Higher than grade 2 or greater than 1.56 in H/N ratio seemed to be an indicator for better prognosis. 99m Tc-MDP bone scintigraphy can be a useful method to evaluate the vascularized status of implants. Adequate time for 99m Tc-MDP bone scintigraphy after enucleation and evisceration was 11~20 weeks.