3PC-032 Autologous tissue adhesive in ophthalmological surgery

Background and importance Sutures to replace tissue adhesives have enhanced importance. However, commercialised drugs are allogenic, synthetic and expensive, increasing surgery costs. Aim and objectives To produce an autologous tissue adhesive (ATA) easily compounded in ophthalmological surgery. To show evidences of the safe and effectiveness of the ATA in preclinical studies. Material and methods To produce 4 mL of ATA based on a fibrinogen (FC) and thrombin concentrate (TC) (proportion1:1), 20 mL of donor blood plasma were precipitated with protamine to prepare FC, and then 20 mL of plasma were precipitated with acetic acid to obtain a TC in a buffer (CaCl2, NaHCO3, NaCl). Drug was conditioned in two 2 mL syringes for topical ophthalmic administration by mixing with a needle. The in vitro toxicity of the drug was studied in a human corneal epithelial model (described as QobuR), to evaluate the grade of irritation after 30 min of exposition time.1 Pterygium surgery was performed in four eyes of white New Zealand rabbits, using ATA to fix a frontal conjunctival autograft (4×5 mm) into the temporal bulbar conjunctive. The grafted eyes were evaluated in vivo by clinical evaluation for 14–28 days and ex vivo by histology. Results ATA produced from each donor showed a mean of 18.0 g/L of fibrinogen and 1500 UI/mL of thrombin. ATA instantly produced homogeneous clots when it was mixed with a needle. Three in vitro studies of four ATA showed non-irritation due to high survival cell viabilities (>80%). Good preclinical results were found: 20 mm2 autograft could be fixed successfully. Time for complete tissue adhesion was minimal (3–5 min). Inflammation and adverse events were absent in all cases. The prospective clinical evaluation was positive for follow-up in all cases and included integration and vascularisation of the grafts. Histology supported the in vivo evidence. Staining of the autograft section showed inner vessels and the regeneration of the surrounding conjunctive tissue. Conclusion and relevance It is possible to compound an ATA easily from whole blood, in a hospital pharmacy, for ophthalmological surgery, where the necessary volume is very low. This ATA was safe and effective, supported by our preclinical studies. This ATA could allow the possibility of replacing the suture in surgery with a low cost drug. References and/or acknowledgements 1. https://www.ncbi.nlm.nih.gov/pubmed/30690064 No conflict of interest.