Valutazione del danno da stress ossidativo come indicatore di effetto biologico dell'esposizione professionale a xenobiotici

Oxidative DNA damages determine the activation of cell repair processes. These processes originate repair products, including the most studied one, 8-hydroxy-2’-deoxyguanosine (8-OH-dG). Several analytical techniques have been applied to measure urinary 8-OH-dG, but a discrepancy in basal urinary 8-OH-dG levels has been noted when comparing chromatographic techniques with immunoenzymatic assays (ELISA). Our laboratory has developed a fully validated, liquid chromatography-tandem mass spectrometry method presenting high sensitivity and specificity, which has participated in an inter-laboratory validation of assays for the measurement of urinary 8-OH-dG (ESCULA project). Mass Spectrometric techniques showed more accuracy and specificity than immunoenzymatic methods. Human spot urine samples were analyzed in order to investigate the possibility to correct urinary lesion measurements for creatinine and to evaluate the intra- and inter-day variability of 8-OH-dG excretion in urine. Our results confirm the opportunity to delve into these issues. Finally, we measured urinary 8-OH-dG in workers exposed to antineoplastic drugs and in a group of unexposed subjects to evaluate the relationship between occupational exposure and oxidative damage related to the internal dose. We found higher levels of 8-OH-dG in exposed nurses, but, as compared to the non-exposed subjects, the difference was not statistically significant, probably do to the very low level of exposure. The scientific literature is rapidly developing on the topic of DNA damage and related repair capacity. Nevertheless, further studies are needed to achieve a better understanding of the sources of DNA lesions in urine and their significance, both in clinical and occupational medicine.

The biological basis of autism spectrum disorders: evaluation of oxidative stress and erytrocyte membrane alterations

This case-control study involved a total of 29 autistic children (Au) aged 6 to 12 years, and 28 gender and age-matched typically developing children (TD). We evaluated a high number of peripheral oxidative stress parameters, erythrocyte and lymphocyte membrane functional features and membrane lipid composition of erythrocyte. Erythrocyte TBARS, Peroxiredoxin II, Protein Carbonyl Groups and urinary HEL and isoprostane levels were elevated in AU (confirming an imbalance of the redox status of Au); other oxidative stress markers or associated parameters (urinary 8-oxo-dG, plasma Total antioxidant capacity and plasma carbonyl groups, erythrocyte SOD and catalase activities) were unchanged, whilst peroxiredoxin I showed a trend of elevated levels in red blood cells of Au children. A very significant reduction of both erythrocyte and lymphocyte Na+, K+-ATPase activity (NKA), a reduction of erythrocyte membrane fluidity, a reduction of phospatydyl serine exposition on erythrocyte membranes, an alteration in erythrocyte fatty acid membrane profile (increase in MUFA and in ω6/ω3 ratio due to decrease in EPA and DHA) and a reduction of cholesterol content of erythrocyte membrane were found in Au compared to TD, without change in erythrocyte membrane sialic acid content and in lymphocyte membrane fluidity. Some Au clinical features appear to be correlated with these findings; in particular, hyperactivity score appears to be related with some parameters of the lipidomic profile and membrane fluidity, and ADOS and CARS score are inversely related to peroxiredoxin II levels. Oxidative stress and erythrocyte structural and functional alterations may play a role in the pathogenesis of Autism Spectrum Disorders and could be potentially utilized as peripheral biomarkers.