Avaliação da atividade das enzimas NTPDase, 5’ nucleotidase, adenosina deaminase e parâmetros de estresse oxidativo em portadores de Síndrome de Down

Abstract

Alterations in the platelets and oxidative stress play a role in the pathogenesis of DS. The NTPDase, 5´- nucleotidase and adenosine deaminase (ADA) represent an important therapeutic target since they interfere in the extracellular nucleotide pool altering several platelet functions. We evaluated the ectonucleotidase activities and oxidative stress parameters in samples of DS individuals and healthy subjects. The population consisted of 28 subjects with DS and 28 healthy subjects. Ten milliliters of blood was obtained from each subject and used for platelet and serum preparation. The NTPDase activity using ATP as substrate was increased in platelets of DS patients in relation to the control group (P<0.05); however, no alterations were observed in the ADP hydrolysis. A decrease in the 5´- nucleotidase activity and an increase in the ADA activity was observed in platelets of DS subjects when compared to healthy individuals (P<0.05). Lipid peroxidation and total thiol content was decreased in serum of DS individuals. Furthermore, superoxide dismutase and catalase activities were increased in whole blood of this group (P<0.05). These findings suggest that alterations in the ectonucleotidase activities in platelets as well as changes in the oxidative stress parameters may contribute to the clinical features of DS.