Lactoferrin is a naturally occurring iron-binding glycoprotein, produced and secreted by mucosal epithelial cells and neutrophils in various mammalian species, including humans. It is typically found in fluids like saliva, milk and tears, where it reaches the maximum concentration. Thanks to its unique anti-inflammatory, antioxidant and antimicrobial activities, topical application of lactoferrin plays a crucial role in the maintenance of a healthy ocular surface system. The present review aims to provide a comprehensive evaluation of the clinical applications of lactoferrin in ocular diseases. Besides the well-known antibacterial effect, novel interest has been rising towards its potential application in the field of dry eye and viral infections. A growing body of evidence supports the antimicrobial efficacy of lactoferrin, which is not limited to its iron-chelating properties but also depends on its capability to directly interact with pathogen particles while playing immunomodula...

Lactoferrin is a protein of mammalian origin secreted in the milk of several animals, including human beings, cows, horses, pigs, goats and mice (Masson & Heremans, 1971). From the moment that bovine (Tomita et al., 2009) and human lactoferrin (Weinberg, 2001) were isolated from the milk of their respective species, they began to receive great attention due to their multifunctional properties that are distinctive from lactoferrin from other mammals. In general, lactoferrin is regarded as a modulator of humoral and cellular components involved in inflammatory and immune responses (Actor et al., 2009; Legrand et al., 2004), which has broad implications. For instance, lactoferrin displays antimicrobial activity against a wide range of pathogens, including virus, bacteria, fungi and parasites (Jenssen & Hancock, 2009). It is also able to promote skin integrity by regulating the generation of humoral components of the inflammatory and immune responses, including such cytokines as the tumor necrosis factor (TNF) alpha and interleukin (IL) 1beta, as well as the migration of Langerhans cells (Kimber et al., 2002). Moreover, lactoferrin enhances collagen gel contractile activity of fibroblasts, leading to skin wound healing (Takayama & Takezawa, 2006).

To study the expression of basic fibroblast growth factor (bFGF) in the early phases of corneal wound healing in the presence or absence of granulocytes. A central penetrating corneal alkali wound was inflicted to one eye in each of 14 rabbits under general anaesthesia. Subsequently, seven of the rabbits were given fucoidin i.v. for 36 hours in order to block the selectins on the vascular endothelium, thus preventing blood granulocytes from entering the tissues. Then, corneas were prepared, stained for bFGF and evaluated by light microscopy. Whereas normal corneal epithelium expressed bFGF weakly, conjunctival epithelium did so strongly, particularly the goblet cells. The corneal endothelium showed medium staining, while keratocytes and vascular endothelial cells did not consistently express bFGF. After 36 hours of wound healing, a marked up-regulation of bFGF expression was observed in the corneal epithelial and endothelial cells, as well as in the keratocytes, that were migrating into the wound. No other changes were noted. None of these features were modulated when granulocyte emigration was prevented by fucoidin administration. The difference in bFGF expression between the corneal and conjunctival epithelium suggests a role for this growth factor in the barrier function at the limbus. Moreover, the specific presence of bFGF in cells migrating into the wound indicates the participation of bFGF in corneal wound healing. Expression of bFGF was independent of granulocytes.