Autologous serum eye drops diluted with sodium hyaluronate: clinical and experimental comparative study

Purpose: To assess the efficacy of sodium hyaluronate as vehicle for diluting autologous serum. Methods: The concentration and temporal stability of EGF, TGF-, PDGF-AB and albumin in fresh and frozen samples of autologous serum diluted with sodium hyaluronate and saline solution, as well as the pH, osmolarity and density was studied. In parallel, the clinic effects of autologous serum diluted to 20% with sodium hyaluronate were compared with another solution of autologous serum diluted to 20% with saline in a prospective, comparative, randomized and double-blind study in 26 patients (52 eyes) with Sjogren syndrome. Patients underwent a complete ophthalmic assessment including tear film evaluation and corneal and conjunctival impression cytology at the beginning of the study and 2months later. Results: The growth factor (GF) concentration remained stable during 1month at 4 degrees C both in fresh and defrosted samples without any differences being found between both preparations. No differences were found related to osmolarity, pH and density between these preparations before and after frosting. Autologous serum diluted with sodium hyaluronate caused a significant improvement of the tear film stability, fluorescein and rose Bengal stain, break-up time, corneal and conjunctival squamous metaplasia as well as in the patient subjective perception. Conclusions: Sodium hyaluronate is an excellent vehicle for diluting autologous serum due to the gradual release of GF and increasing their duration and effect on the ocular surface. Preparations diluted with sodium hyaluronate are better tolerated by patients and require a lower number of drops administrations.