An Association of Vitamins A and E with Hyaluronic and Lactobionic Acids may Prevent Molecular Changes Associated with Keratocyte to Myofibroblast Transition

Inflammatory events in the corneal stroma may activate keratocytes and trigger their transition towards myofibroblasts,which now produce different extracellular matrix(ECM)proteins thus causing corneal opacification.Corneal haze is a frequent side effect after photorefractive keratectomy(PRK)to correct high myopia.Currently,a preventive treatment with mitomycin-c can be used to limit the occurrence of this phenomenon.However,mitomycin-c is a toxic drug,not devoid of side effects,which may occasionally involve the corneal endothelium.Therefore,we have searched for a less risky,natural way,to prevent keratocytes transition.To this purpose,we have used as markers of the phenotype switch the proteins lumican(highly expressed by keratocytes and much less by myofibroblasts)and smooth muscle actin(αSMA)(highly expressed by myofibroblasts and poorly found in keratocytes),beside Fibronectin(Fn),the expression of which is also increased by transforming growth factor-beta(TGFβ)treatment.Treatment of human keratocytes with TGFβwas used to induce the protein shift.Among different possible candidates,we have found that vitamins A and E,hyaluronic and lactobionic acids may prevent,either alone,or much better in association,the shift in the ratio between lumican andαSMA and the increased Fn expression.In conclusion,it could be speculated that topic treatment of the ocular surface with an association of these four compounds could be able to prevent or at least limit the occurrence of post-PRK corneal haze,with the additional advantage of lubrication,hydration and antioxidant defense exerted by these molecules.

Transient global amnesia and stroke: not that benign?

After more than 50 years since Fisher and Adams’original description in 1964,1 transient global amnesia(TGA)is still a puzzling syndrome.Over time,several mechanisms have been proposed for TGA pathogenesis,including venous congestion,cortical spreading depression,seizures and arterial ischaemia.2–4 A sufficient amount of studies in favour and against each of these mechanisms has emerged,fostering uncertainty regarding aetiology as well as prognosis.To this extent,most of the controversy stands on whether TGA represents a risk factor for stroke,or whether this is just as benign as originally thought.