Formation of Hydroxyl Radicals in the Human Lens is Related to the Severity of Nuclear Cataract

The Impact of Senile Cataract Maturity on Blood Oxidative Stress Markers and Glutathione-Dependent Antioxidants: Relations with Lens Variables

“…Intercompartmental correlations are given as Pearson's correlation coefficient (r) and p-value. with the previous reports (1)(2)(3)(4)(5). The underlying reasons of reduced lens GPx, GR and GST activities in advanced disease are highly complex, as can be the result of downregulated or insufficiently expressed genes (14), as well as oxidative modifications of enzymatic molecules, potentiated by extensive loss of the cellular GSH pool (25,26).…”

“…Surgical extraction of the opaque lens with intraocular implantation of an artificial lens is currently the only way of treatment, despite of experimental evidence that antioxidant vitamins such as ascorbate, carotenoides and riboflavin may have an anti-cataractogenic effect. Previous studies, including those from our laboratory, have shown that lenticular oxidative stress largely corresponds to the severity of SC (1)(2)(3)(4). This relationship with systemic oxidative stress is not well established, although it can be implicated in the severity of several senescence-related diseases and risk factors for SC genesis.…”

“…An increasing body of evidence suggests that ocular oxidative stress, defined as an imbalance between oxidants and antioxidants, is the key pathophysiological mechanism of senile cataract (SC) ge nesis (1)(2)(3)(4)(5). Hydrogen peroxide is the major ocular oxidant, and can be formed in excess during the photo oxidation of endogenous ascorbate and structural lens proteins, the crystallins (1).…”

“…Exposure of the lens to hydrogen peroxide is well known to cause lipid peroxidation (LPO) of polyunsaturated fatty acids, loss of antioxidants, and oxidation, cross-linking and insolubilization of crystallins. The resulting light scattering and lens opacification generally resemble the changes seen in human SC (2). Some other oxidants like LPO adducts, including organic hydroperoxides and ma londialdehyde (MDA), also have significant cataractogenic potential (1), and although they can be pre sent in systemic circulation at micromolar le vels and act as toxic messengers, the reports regarding the blood oxidative stress markers in patients with SC are largely inconsistent (5)(6)(7)(8)(9)(10)(11).…”

Plasma 8-Isoprostane Concentrations in Patients with Age-Related Cataracts

“…Epidemiologic studies have shown that potential risk factors include age, sex female, exposure to ultraviolet light, smoking, diabetes, and oxidative stress (1)(2)(3)(4). Opacification of the ocular lens may be initiated or promoted by oxidative damage, and data in the literature support an important role of oxidative damage in cataract formation (5,6 ). Although animal experiments show evidence for a protective role of antioxidants (7,8 ), the association between low concentrations of antioxidants and increased risk of cataracts remains controversial.…”