IL-1β, IL-6, IL-2, IL-10 and VEGF stability in autologous and allogeneic serum-based eye drops

Abstract

Serum-based eye drops are an effective treatment for dry eye syndrome. Most of the proteins and growth factors in serum are thought to remain stable for several months, but there are no standardized protocols for preparation of the product. Also, the time from thawing to drop administration is of significant importance. Stability testing of IL-1β, IL-6, IL-2, IL-10 and VEGF using flow cytometry was performed. Concentrations in samples thawed prematurely and directly before measurement and before after 5-month storage were studied. Mean concentration in the samples thawed immediately before measurement is higher in VEGF and IL-10 and in samples thawed prematurely concentrations of in IL-1β, IL-2, IL-6. Results for measuring the stability after 5-moth storage were: in most samples the levels of IL-1β and IL-2 interleukins were higher after 5-month storage, while the IL-6 and IL-10 and VEGF were lower. Premature thawing and storage of serum at 20°C significantly alters the concentration of cytokines, which reduces the effectiveness of the serum eye drops. Storing serum at -20°C for several months influences the change in VEGF and the studied cytokines concentration. It is necessary to extend the studies to other serum proteins and to establish a shelf life.