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The article presents the results of an experimental and morphological study of combined antiangiogenic effect of photodynamic therapy with Photosens photosensitizer and Avastin (bevacizumab) on neovascularization process in corneal stroma. The combined approach has demonstrated an advantage over separate application of these methods, what, however, has to be proved clinically.

Russian and foreign literature data on current methods of anti-angiogenic influence on newly formed corneal vessels in experiment and clinic was analyzed. Their advantages and negative effects are highlighted and the information about their combined use is provided. The conclusion about the need of further studies is made.

Pigment epithelium-derived factor (PEDF), a 50 kDa secreted glycoprotein, is among the most potent endogenous inhibitors of angiogenesis. PEDF-derived fragment (44-77) possesses antiangiogenic properties of the full-sized protein and is a potential drug candidate for the treatment of ocular neovascular diseases. In this study we propose an efficient scalable biotechnological method for the production of PEDF (44-77) as part of a fusion protein with SspDnaB intein. The fusion protein was obtained in bacterial E. coli cells in the form of inclusion bodies, solubilized and subjected to autocatalytic cleavage with the release of PEDF (44-77) (yield, 77%). The target peptide was separated from the intein using tangential ultrafiltration. The final purification of PEDF (44-77) was performed by reversed-phase HPLC. The yield of the target peptide (purity, 99%) was 65 mg per 1 liter of culture. Antiangiogenic activity of the obtained peptide was studied in vitro using murine endothelial cells SVEC-4-10. PEDF (44-77) suppressed proliferation of endothelial cells by 53% and inhibited endothelial cell tube formation at the concentration of 1 nM. The ability of the recombinant PEDF (44-77) to block initial stages of angiogenesis was demonstrated using the model of rabbit corneal neovascularization.

The present paper deals with the study of the efficiency of oral use of the antioxidative drug Immugen (a complex of alpha-tocopherol, oubichinone, selenium aspartate, methionine, and soyabean phospholipids) on a rabbit model of severe alkaline-induced corneal burn. The investigations have indicated that addition of Immugen to the rabbit feed exerts a significant positive effect on the parameters of the local antioxidative system of the eye and causes an increase in the activity of superoxide dismutase and catalase, and, on day 14, in antioxidative activity. The early experimental periods were marked by a slight rise in the frequency of deep corneal ulcerations. Moreover, the long-term clinical effect of use of Immugen appears as a significant increase in the area of the transparency-preserving affected cornea. The findings suggest that the antioxidants can show their optimal effect in the complex therapy for burn processes, including the use of proteinase inhibitors.

Experimental denervation of the central portions of the cornea in rabbits permitted us to hypothesize "autonomism" of corneal tissues, manifesting as soon as corneal tissues loose connection to the nervous system inhibiting cell growth and division. It involved edema, decreased differentiation, loss of correlation between the epithelium and stroma, submerged growth, and eventually even transformation into a sort of tissue culture in the organism. Experiments demonstrated that increased tissue differentiation is paralleled by in-growth of nerve endings. The degree of differentiation and functional intactness of tissues is maintained by the nervous system. If there are no conditions for reinnervation or the injury (irritation) is repeated, the process transforms into pathological: cords of immature tissue penetrate into the depth of the eye from open edges of corneal and scleral wounds, granulation of chronic wounds is abnormal, and pretumor states of tissues develop. Further status of such tissue apparently depends on new vessels, repeating the transformation of epithelial stroma and connective tissue. Increased growth of the epithelium and stromal elements leads to thickening of vascular wall, dilatation of vascular lumen, and to complete obliteration. Repeated irritation resumes the process of tissue transformation with formation of new vessels. Angiogenesis is apparently related to denervation, and each new irritation induces repeated vascular growth. Treatment and prevention are to be aimed at removal of the irritants and improvement of the nervous system function maintaining the maturity of tissues in an organism.