Abstract
Rapid and adequate vascularization is vital to the long-term success of porous orbital enucleation implants. In this study, porous hydroxyapatite (HA) scaffolds coated with vascular endothelial growth factor (VEGF)-functionalized collagen (COL)/heparin (HEP) multilayers (porosity 75%, pore size 316.8 ± 77.1 μm, VEGF dose 3.39 ng/mm3) were fabricated to enhance vascularization by inducing the differentiation of mesenchymal stem cells (MSCs) to endothelial cells. The in vitro immunofluorescence staining, quantitative real-time polymerase chain reaction (qRT-PCR), and western blotting results demonstrated that the expression of the endothelial differentiation markers CD31, Flk-1, and von Willebrand factor (vWF) was significantly increased in the HA/(COL/HEP)5/VEGF/MSCs group compared with the HA/VEGF/MSCs group. Moreover, the HA/(COL/HEP)5 scaffolds showed a better entrapment of the MSCs and accelerated cell proliferation. The in vivo assays showed that the number of newly formed vessels within the constructs after 28 d was significantly higher in the HA/(COL/HEP)5/VEGF/MSCs group (51.9 ± 6.3/mm2) than in the HA (26.7 ± 2.3/mm2) and HA/VEGF/MSCs (38.2 ± 2.4/mm2) groups. The qRT-PCR and western blotting results demonstrated that the HA/(COL/HEP)5/VEGF/MSCs group also had the highest expression of CD31, Flk-1, and vWF at both the mRNA and protein levels.
Highlights
The removal of an eye may be necessary in cases of severe ocular trauma, intraocular malignancy, blind painful eye, prevention of sympathetic ophthalmia, and cosmesis
Filament-like structures appeared after assembly of the (COL/HEP)[5] multilayers (Fig. 1B), which were consistently observed on the internal surface of the pore walls under CLSM (Fig. 1C, FITC-labelled collagen was used, green)
Previous data showed that the thickness of five COL/HEP multilayers assembled on Si wafers is 35.5 ± 0.5 nm, as measured by spectroscopic ellipsometry[30]
Summary
The removal of an eye may be necessary in cases of severe ocular trauma, intraocular malignancy, blind painful eye, prevention of sympathetic ophthalmia, and cosmesis. The ability of biochemical and physical cues to promote the vascularization of a transplantable implant is a key issue in tissue engineering. A variety of approaches, including scaffold functionalization, material surface modification, and cell-based techniques, have been developed for this purpose[12]. The rapid vascularization of tissue-engineered grafts can be achieved by combining the strategies of stem cell therapy, material surface modification, and scaffold functionalization[16]. It is suggested that VEGF has a strong ability to induce the MSCs to differentiate into endothelial cells and promote vascularization, with an outcome that is better than that of the ECs19. Grafts loaded with VEGF can be part of a useful strategy to stimulate and induce angiogenesis in tissue-engineered constructs[29]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
