Vitreous albumin redox state in open-angle glaucoma patients and controls: a pilot study.

PURPOSE: Numerous studies suggest that reactive oxygen species play a crucial role in the development of glaucoma. Since glaucoma patients exhibit posterior vitreous detachment earlier than controls, it has been suggested that reactive oxygen species-increased in glaucoma-also affect the vitreous. In the present study we evaluated the influence of open-angle glaucoma oxidative stress on the redox state of vitreous albumin. METHODS: Albumin redox states of the vitreous and plasma were evaluated in 22 subjects-11 open-angle glaucoma patients and 11 controls-matched for age, gender, and vitreous state. According to the redox state of cysteine-34, albumin can be separated into: human mercaptalbumin (the thiol form), human nonmercaptalbumin1 (a reversible modification due to mild oxidation), and human nonmercaptalbumin2 (an irreversible modification due to severe oxidation). RESULTS: Albumin of both, the open-angle glaucoma group and the control group, was more oxidized in the vitreous compared to plasma. Furthermore, significantly higher human nonmercaptalbumin1 fractions were found in the vitreous of open-angle glaucoma patients compared to controls. No significant differences were found in the plasma albumin fractions between the groups. CONCLUSION: Our results support the hypothesis that oxidative stress plays a crucial role in open-angle glaucoma and that reactive oxygen species in glaucomatous eyes may also affect the vitreous.

Gender differences in albumin and ascorbic acid in the vitreous antioxidant system.

Ascorbic acid is present at high concentrations in the vitreous and plays a central role in vitreous redox chemistry. Albumin is the main protein in the vitreous with antioxidant properties and occurs in different oxidation states, which can be used as redox indicators, but have not been studied in the vitreous. This study, therefore, addressed the vitreous redox state of cysteine-34 of albumin in relation to the ascorbic acid content, which has been suggested to exert a main function in detoxifying reactive oxygen in the vitreous. A total of 58 vitreous samples obtained from patients undergoing vitrectomy were analyzed for (i) human mercaptalbumin (HMA), the reduced thiol form; (ii) human non-mercaptalbumin1 (HNA1), a reversible oxidative modification with a disulfide at cysteine-34; and (iii) human non-mercaptalbumin2 (HNA2), a non-reversibly (highly) oxidized form of albumin; as well as (iv) ascorbic acid concentrations, to study possible relations. In addition, blood samples were taken to compare albumin redox state between plasma and the vitreous. Vitreous albumin showed greater variability in the redox state of cysteine-34 and a shift to the oxidized fractions compared to plasma albumin (P < 0.001). A strong positive relation was observed between the vitreous ascorbic acid concentrations and the reversibly oxidized form, HNA1 (P < 0.001), and a negative relation with the reduced form, HMA. Positive relations between ascorbic acid and HNA1 in the vitreous were stronger in men than in women. In contrast to HMA and HNA1, there was a distinct gender difference noted for the irreversibly oxidized form, HNA2. While males showed a positive relation between the vitreous ascorbic acid concentrations and HNA2, there was no correlation found with HNA2 in females. Our results support the view that ascorbic acid, by decreasing either directly or indirectly the concentrations of molecular oxygen, generates hydrogen peroxide, and that thiols, including HMA, are acting as antioxidants. This study for the first time provides evidence that vitreous albumin can be used as a marker molecule for the appearance of reactive oxygen species in the vitreous of patients undergoing vitrectomy. Moreover, it can be shown that there are gender differences in vitreous ascorbic acid and albumin concentrations as well as in oxidation state of vitreous albumin.

Magnetomitotransfer: An efficient way for direct mitochondria transfer into cultured human cells.

In the course of mitochondrial diseases standard care mostly focuses on treatment of symptoms, while therapeutic approaches aimed at restoring mitochondrial function are currently still in development. The transfer of healthy or modified mitochondria into host cells would open up the possibilities of new cell therapies. Therefore, in this study, a novel method of mitochondrial transfer is proposed by anti-TOM22 magnetic bead-labeled mitochondria with the assistance of a magnetic plate. In comparison to the passive transfer method, the magnetomitotransfer method was more efficient at transferring mitochondria into cells (78-92% vs 0-17% over 3 days). This transfer was also more rapid, with a high ratio of magnetomitotransferred cells and high density of transferred mitochondria within the first day of culture. Importantly, transferred mitochondria appeared to be functional as they strongly enhanced respiration in magnetomitotransferred cells. The novel method of magnetomitotransfer may offer potential for therapeutic approaches for treatment of a variety of mitochondria-associated pathologies, e.g. various neurodegenerative diseases.