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Proc Natl Acad Sci U S A. 2009 Mar 10;106(10):3941-5. doi: 10.1073/pnas.0813409106. Epub 2009 Feb 17.

Inherited disorders affecting mitochondrial function are associated with glutathione deficiency and hypocitrullinemia.

Author information

1
Department of Genetics, Stanford University, Stanford, CA 94305, USA. atkuri@stanford.edu

Abstract

Disorders affecting mitochondria, including those that directly affect the respiratory chain function or result from abnormalities in branched amino acid metabolism (organic acidemias), have been shown to be associated with impaired redox balance. Almost all of the evidence underlying this conclusion has been obtained from studies on patient biopsies or animal models. Since the glutathione (iGSH) system provides the main protection against oxidative damage, we hypothesized that untreated oxidative stress in individuals with mitochondrial dysfunction would result in chronic iGSH deficiency. We confirm this hypothesis here in studies using high-dimensional flow cytometry (Hi-D FACS) and biochemical analysis of freshly obtained blood samples from patients with mitochondrial disorders or organic acidemias. T lymphocyte subsets, monocytes and neutrophils from organic acidemia and mitochondrial patients who were not on antioxidant supplements showed low iGSH levels, whereas similar subjects on antioxidant supplements showed normal iGSH. Measures of iROS levels in blood were insufficient to reveal the chronic oxidative stress in untreated patients. Patients with organic acidemias showed elevated plasma protein carbonyls, while plasma samples from all patients tested showed hypocitrullinemia. These findings indicate that measurements of iGSH in leukocytes may be a particularly useful biomarker to detect redox imbalance in mitochondrial disorders and organic acidemias, thus providing a relatively non-invasive means to monitor disease status and response to therapies. Furthermore, studies here suggest that antioxidant therapy may be useful for relieving the chronic oxidative stress that otherwise occurs in patients with mitochondrial dysfunction.

PMID:
19223582
PMCID:
PMC2656184
DOI:
10.1073/pnas.0813409106
[Indexed for MEDLINE]
Free PMC Article

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