Blood‐derived trophic factors for the treatment of ocular surface diseases

Abstract

The use of blood‐derived products (Eye Drop of Human Origin—EDHO; in Italian: Emocomponents for Not Transfusional Use, EUNT) for the treatment of various ocular surface diseases has become increasingly utilized in ophthalmic practice over the years. In particular, they are recommended as a third line option, when conventional tear substitutes, or active drugs, such as corticosteroids or Cyclosporine A, result unsuccessful in controlling either signs and, perhaps most importantly, subjective symptoms of discomfort and pain. The rationale for their use is based on the stimulation of cell proliferation and migration through the supply of metabolically active substances, in particular growth factors, and definitely mimicking the function of natural tears.EDHO have been used for the treatment of various ocular surface diseases, including dry eye, persistent corneal epithelial defect, corneal ulcer, neurotrophic keratitis, ocular surface burn, recurrent corneal erosion and limbal stem cell deficiency. However, the therapeutic potential of these products is still to be fully explored, as randomized clinical trials and internationally recognized harmonized guidelines are still needed to provide better evidence, improve quality of the final products and lead to a more widespread use of these therapies in daily clinical practice. The autologous source is still quite popular, although allogeneic sources appear to be a promising innovation. These might offer the solution of obtaining in advance products tailored for each patient and ocular surface disease, at scalable concentrations based on the severity of the disease and clinical parameters. There remain many unanswered questions regarding what might be considered optimal treatment, sketched as “The 5 Ws (and 2 H) for blood based eye drops”, to quote a review from our group (doi: 10.3390/jcm8091478). This presentation will discuss: 1. who is the patient to be treated, in terms of disease type, severity, and stage?; 2. Why is an EDHO needed, in terms of a target indication?; 3. When is it appropriate to prescribe an EDHO therapy?; 4. Where are EDHO be dispensed, and is a national/regional program a feasible solution to optimize resources?; 5. What is the EDHO of choice, which source and preparation are targeted for a given patient? And further: 1. how is EDHO standardized in terms of processing to ensure an optimal dilution, solvent, dispenser, storage time?; 2. How is EDHO delivered to the ocular surface, in terms of form, dose‐size modulation, length of treatment?An interdisciplinary work with transfusional medicine specialists is imperative to share information and competences, to achieve a better clinical management.