Oxidative stress in trisomy 21. A possible role in cataractogenesis.
Previous studies have suggested that free radicals and related species play a role in lens damage. The molecules involved may include proteins, lipids and DNA. Focal cortical changes and cortical liquefaction have been reported in patients with Down's syndrome over the age of 15 years. There is evidence supporting the hypothesis that trisomy 21 patients have an increase in free radical reactions and lipoperoxidation susceptibility. This could be due to an increase in the H2O2 generation catalysed by CuZn SOD although the activity of other gene products coded for on chromosome 21 cannot be excluded. Thiobarbituric acid reactive products were measured in human erythrocytes of nine DS patients and nine age-matched controls. There was a significant increase in the first group (21.0 +/- 2.3 nmol MDA/g Hb vs 16.4 +/- 2.9 nmol MDA/g Hb; p less than or equal to 0.01). In plasma, however, TBA products and antioxidant levels (ascorbic acid, tocopherol and uric acid) were not significantly different. Further studies should be carried out, namely through the use of more specific and sensitive methods, to assess the possible association between oxidative stress and cortical lens damage in DS patients.
Brás
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A
Department of Genetics, Faculty of Medical Sciences, New University of Lisbon, Portugal.
Monteiro
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C
Rueff
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J
D000293:Adolescent; D000328:Adult; D001205:Ascorbic Acid / Q000097:blood; D002386:Cataract / Q000209:etiology*; D002648:Child; D002675:Child, Preschool; D004314:Down Syndrome / Q000097:blood* / Q000150:complications; D004912:Erythrocytes / Q000201:enzymology; D005609:Free Radicals; D006801:Humans; D007223:Infant; D015227:Lipid Peroxidation; D010100:Oxygen / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000097:blood*; D013858:Thiobarbiturates / Q000378:metabolism; D014527:Uric Acid / Q000097:blood; D014810:Vitamin E / Q000097:blood
D005609:Free Radicals; D013858:Thiobarbiturates; D014810:Vitamin E; D014527:Uric Acid; D013482:Superoxide Dismutase; C029684:thiobarbituric acid; D001205:Ascorbic Acid; D010100:Oxygen