Why do cataracts appear in cases of diabetes or galactosemia?
- Autores: Jesús Pintor
- Localización: Journal of Emmetropia: Journal of Cataract, Refractive and Corneal Surgery, ISSN-e 2171-4703, Vol. 3, Nº. 4, 2012, págs. 209-212
- Idioma: inglés
- Texto completo no disponible (Saber más ...)
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Resumen
ABSTRACT: The origins of cataracts can be very diverse. It is nevertheless quite clear that in many cases cataracts occur as a consequence of changes in the metabolism of carbohydrates. In this sense, diseases such as diabetes and galactosemia can initiate the process of cataractogenesis due to an excess of sugars in the blood and in the aqueous humour. The lens can use carbohydrates by means of three metabolic pathways: glycolysis, the pentose phosphate shunt and the polyol pathway. When the first two are saturated due to the excess of sugars, the polyol route starts to become relevant. This pathway mainly produces sorbitol and galactitol, which normally accumulates within the lens. The increase in these polyols generates an osmotic force that facilitates the entrance of water into the lens.
Moreover, the high sugar levels glycosylate proteins, thus facilitating their self-aggregation.
The mentioned protein aggregation plus the massive water in ux produce changes in lens protein organization and visible aggregates can be observable. These protein clusters disperse light and impede the proper formation of images in the retina. There are ways to delay the development of this type of cataract, most of them interfering in the enzymes producing polyols. In particular, the development of RNAi for some lens proteins could help to halt the appearance of cataracts.
