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Fanconi anaemia (FA) is a cancer-prone genetic disorder that is characterised by cytogenetic instability and redox abnormalities. Although rare subtypes of FA (B, D1 and D2) have been implicated in DNA repair through links with BRCA1 and BRCA2, such a role has yet to be demonstrated for gene products of the common subtypes. Instead, these products have been strongly implicated in xenobiotic metabolism and redox homeostasis through interactions of FANCC with cytochrome P-450 reductase and with glutathione S-transferase, and of FANCG with cytochrome P-450 2E1, as well as redox-dependent signalling through an interaction between FANCA and Akt kinase. We hypothesise that FA proteins act directly (via FANCC and FANCG) and indirectly (via FANCA, BRCA2 and FANCD2) with the machinery of cellular defence to modulate oxidative stress. The latter interactions may co-ordinate the link between the response to DNA damage and oxidative stress parameters (3, 6-12).

PubMedID: 16036329 The hypothesis was tested that Werner syndrome (WS) phenotype might be associated with an in vivo prooxidant state. A set of redox-related endpoints were measured in three WS patients, two of their parents, and 99 controls within a study of some cancer-prone and/or ageing-related genetic disorders. The following analytes were measured: (a) leukocyte 8-hydroxy-2'-deoxyguanosine; (b) glutathione from whole blood, and (c) plasma levels of glyoxal, methylglyoxal, 8-isoprostane, and some plasma antioxidants (uric acid, ascorbic acid, ?- and ?-tocopherol). Leukocyte 8-hydroxy-2'-deoxyguanosine levels showed a significant increase in the 3 WS patients vs. 85 controls (p < 10-7). The disulfide glutathione:glutahione ratio was significantly altered in WS patients (p = 0.005). Glyoxal and methylglyoxal levels were significantly increased (p = 0.018 and p = 0.007, respectively). The plasma levels of uric acid (p = 0.002) and ascorbic acid (p = 0.003) were also increased significantly in WS patients and in their parents. No significant alterations were found in the plasma levels of ?- and ?-tocopherol, nor of 8-isoprostane. This is the first report of in vivo alterations of oxidative stress parameters in WS patients. Further investigations on more extensive study populations are warranted to verify the relevance of an in vivo prooxidant state in WS patients. © 2005 Taylor & Francis Group Ltd. Universitat de València National Cancer Institute 1Italian National Cancer Institute, I-80131 Naples, Italy, 2Department of Genetics, “Elena d’Aosta” Hospital, I-80136 Naples, Italy, 3Italian National Cancer Institute, IST I-16132 Genoa, Italy, 4Department of Organic Chemistry and Biochemistry, “Federico II” Naples University, I-80126 Naples, Italy, 5Division of Life Sciences, King’s College, London SE1 9NN, UK, 6Department of Physiology, University of Valencia, E-46010 Valencia, Spain, 7Department of Pediatrics, C¸ ukurova University, TK-01330 Adana, Turkey, 8Department of Metabolism and Pathologic Biochemistry, Istituto Superiore di Sanità, I-00161 Rome, Italy, and 9International Atomic Energy Agency-MEL, MC-98000 Principality of Monaco

Some selected oxidative stress parameters were measured in 56 Fanconi anaemia (FA) patients (42 untransplanted and 14 transplanted), 54 FA heterozygotes (parents) and 173 controls. Untransplanted FA patients showed a highly significant increase in leukocyte 8-hydroxy-2’-deoxyguanosine (8-OHdG) (p = 0.00003) and a borderline increase (p = 0.076) in urinary levels of 8-OHdG vs. child controls. These increases were more pronounced in female FA patients (p = 0.00005 for leukocyte 8-OHdG, and p = 0.021 for urinary 8-OHdG). Female FA patients also displayed a highly significant excess of spontaneous chromosomal breaks vs. male patients (p = 0.00026), in the same female:male ratio (≅ 1.4) as detected both for leukocyte and for urine 8-OHdG levels. Plasma methylglyoxal (MGlx) levels were increased in untransplanted FA patients vs. child controls (p = 0.032). The increases in leukocyte and urinary 8-OHdG, and in MGlx levels were detected in young FA patients (≤15 yrs), whereas patients aged 16 to 29 yrs failed to display any differences vs. controls in the same age group. A significant increase in oxidised:reduced glutathione (GSSG:GSH) ratio was observed (p = 0.046) in the FA patients aged ≤15 yrs, whereas those aged 16 to 29 yrs, both untransplanted and transplanted, displayed a decrease (p = 0.06) in the GSSG:GSH ratio vs. the controls of the respective age groups. No significant changes were detected in plasma levels of Vitamin C, Vitamin E, or uric acid. Transplanted FA patients showed lesser alterations in leukocyte 8-OHdG and in GSSG:GSH ratio vs. untransplanted patients. The parents of FA patients displayed a significant increase in plasma MGlx levels (p = 0.0014) vs. adult controls. The results suggest a gender- and age-related modulation of oxidative stress in FA patients. The observed increase in urinary 8-OHdG in untransplanted FA patients suggests a proficient removal of oxidised DNA bases. Key words: Fanconi anaemia; 8-hydroxy-2’-deoxyguanosine; methylglyoxal; glutathione; chromosomal instability

Objective: To evaluate an in vivo pro-oxidant state in patients with ataxia telangiectasia (AT). Methods: A set of oxidative stress endpoints were measured in 9 AT homozygotes, 16 AT heterozygotes (parents) and 83 controls (grouped in age ranges as for patients and parents, respectively). The following analytes were measured: (a) leukocyte 8-hydroxy-2-deoxyguanosine (8-OHdG); (b) blood glutathione (GSSG and GSH); and (c) plasma levels of glyoxal (Glx) and methylglyoxal (MGlx). Results: AT patients displayed a significant decrease in blood GSSG (p=0.012) and in MGlx plasma concentrations (P=0.012). A nonsignificant decrease in the GSSG:GSH ratio (p = 0.1) and a non-significant increase in 8-OHdG and Glx levels were observed in AT patients vs. young controls (age range 4-35 years). AT heterozygotes failed to display any significant changes vs. adult controls (age range 36-68 years). Conclusion: No significant increase in oxidative stress biomarkers was detected in blood from AT patients. The decrease in GSSG and MGlx levels in AT patients may suggest an adaptive response to a pro-oxidant state in AT-related target organs. (c) 2007 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

A comparative evaluation is reported of pro-oxidant states in 82 patients with ataxia telangectasia (AT), Bloom syndrome (BS), Down syndrome (DS), Fanconi anemia (FA), Werner syndrome (WS), and xeroderma pigmentosum (XP) vs 98 control donors. These disorders display cancer proneness, and/or early aging, and/or other clinical features. The measured analytes were: (a) leukocyte and urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), (b) blood glutathione (GSSG and GSH), (c) plasma glyoxal (Glx) and methylglyoxal (MGlx), and (d) some plasma antioxidants [uric acid (UA) and ascorbic acid (AA)]. Leukocyte 8-OHdG levels ranked as follows: WS>BS approximately FA approximately XP>DS approximately AT approximately controls. Urinary 8-OHdG levels were significantly increased in a total of 22 patients with BS, FA, or XP vs 47 controls. The GSSG:GSH ratio was significantly increased in patients with WS and in young (< or =15 years) patients with DS or with FA and decreased in older patients with DS or FA and in AT, BS, and XP patients. The plasma levels of Glx and/or MGlx were significantly increased in patients with WS, FA, and DS. The UA and AA levels were significantly increased in WS and DS patients, but not in AT, FA, BS, nor XP patients. Rationale for chemoprevention trials is discussed.

Objective: To evaluate an association of Bloom syndrome (BS) phenotype with an in vivo prooxidant state. Methods: The following endpoints were measured in 4 BS patients, their 6 parents, and 78 controls: a) leukocyte and urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG); b) blood glutathione (GSSG and GSH), c) plasma levels of some plasma antioxidants (uric acid, UA, ascorbic acid, AA, α- and γ-tocopherol), and of glyoxal (Glx) and methylglyoxal (MGlx). Results: Leukocyte 8-OHdG levels were significantly increased in the 4 BS patients vs. 40 controls (p = 0.04), while the urinary 8-OHdG levels were non-significantly increased in BS patients. Glutathione disulfide levels and GSSG/GSH ratio were significantly decreased in BS patients vs. 44 controls (p = 0.02). The plasma levels of UA in BS patients were significantly increased vs. 24 controls (p = 0.005). No significant alterations were found in the in the plasma levels of Glx, MGlx, AA, and tocopherol. No changes in the tested parameters were found in the BS heterozygotes. Conclusion: This report shows a significant increase in oxidative DNA damage in leukocytes and in plasma UA levels from 4 BS patients. Should these data be confirmed in more extensive BS patient groups, an involvement of oxidative stress in the clinical BS phenotype might be suggested.

Oxidative stress has been associated with Down syndrome (DS) and with its major phenotypic features, such as early ageing. In order to evaluate an in vivo pro-oxidant state, the following analytes were measured in a group of DS patients aged 2 months to 57 years: (a) leukocyte 8-hydroxy-2'-deoxyguanosine (8-OHdG); (b) blood glutathione; (c) plasma levels of: glyoxal (Glx) and methylglyoxal (MGlx); some antioxidants (uric acid, UA, ascorbic acid, AA and Vitamin E), and xanthine oxidase (XO) activity. A significant 1.5-fold increase in 8-OHdG levels was observed in 28 DS patients vs. 63 controls, with a sharper increase in DS patients aged up to 30 years. The GSSG:GSHx100 ratio was significantly higher in young DS patients (< 15 years), in contrast to DS patients aged >= 15 years that showed a significant decrease in the GSSG:GSHx100 ratio ratio vs. controls of the respective age groups. Plasma Glx levels were significantly higher in young DS patients, whereas no significant difference was detected in DS patients aged >= 15 years. Unlike Glx, the plasma levels of MGlx were found to be significantly lower in DS patients vs. controls. A significant increase was observed in plasma levels of UA in DS patients that could be related to an increased plasma XO activity in DS patients. The plasma concentrations of AA were also increased in young (< 15 years) DS patients, but not in older patients vs. controls in the same age range. The levels of Vitamin E in DS patients did not differ from the values determined in control donors. The evidence for a multiple pro-oxidant state in young DS patients supports the role of oxidative stress in DS phenotype, with relevant distinctions according to patients' ages.