Abstract
Purpose:
We evaluated whether plasma rich in growth factors (PRGF) eye drops maintain their composition and biological activity after storage either at 4 C degrees or room temperature for 24 hours, compared to samples storage at - 20 C degrees. These analyses were carried out after storage at -20 C degrees for 15, 30 and 90 days.
Methods:
Plasma rich in growth factors (PRGF) eye drop was obtained using the Endoret (PRGF) kit in Ophthalmology (BTI Biotechnology Institute, S.L., Vitoria, Spain). Briefly, after informed consent was obtained, blood was collected from human blood of ten healthy donors into 9 mL tubes containing sodium citrate as anticoagulant. Blood was centrifuged at 580g for 8 minutes, whole plasma column was drawn off avoiding the buffy coat, activated with calcium chloride, incubated at 37 C degrees for one hour, and finally, the released supernatants were collected by aspiration, filtered and aliquoted and stored at - 20 C degrees until use. Eye-drops were stored at - 20 C degrees for 15, 30 and 90 days. At each time, two aliquots were kept at room temperature or at 4 C degrees for 24 hours. Osmolarity, vitamin A, fibronectin, PDGF-AB, VEGF, EGF and TGF-β1 were quantified in each type of eye-drop. Proliferative and migratory potential of the eye drops at each time and temperature of storage were assayed on primary human keratocytes.
Results:
The growth factor composition of the PRGF eye-drop was not altered in any of the storing conditions. There was only a slight reduction in EGF content. The remaining parameters were not modified. Moreover, no significant differences were observed on keratocyte proliferation and migration activity after treating the cells either with the PRGF-Endoret stored at 4 C degrees or RT for 24 hours. Finally, no microbial contamination was found in any of the biological eye drops at any time or storage conditions.
Conclusions:
Biological activity of the PRGF-Endoret eye drops is preserved after maintaining at room temperature conditions for 24 hours and after storage at -20 C degrees for at least 3 months. All factors excluding EGF were maintained constant. Assuming this, we conclude that this new biological and autologous eye drop can be stored at room temperature for 24 hours maintaining their biological stability, avoiding the microbial contamination.
Keywords: 765 wound healing •
483 cornea: storage •
543 growth factors/growth factor receptors