Neutrophil oxidative metabolism in Down syndrome patients with congenital heart defects.
Down syndrome (DS) occurs when an individual has three, rather than two, copies of the 21st chromosome. Cytosolic superoxide dismutase (SOD-1) is encoded by a gene on chromosome 21 and thus, SOD-1 activity is elevated in patients with DS. Forty percent of all cases with DS are associated with congenital heart defects (CHD). Although the contribution of SOD1 to disease phenotype is unknown, it is considered to be a "molecular marker" of the disease. It was hypothesized herein that the presence of CHD may alter the expression of SOD1 and oxidative metabolism in patients with DS. This hypothesis was tested via four experimental groups as follows: patients with DS without CHD, DS patients with CHD, CHD patients without DS and controls. Expression and activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), myeloperoxidase (MPO), and catalase (CAT) were determined in neutrophils from all experimental groups. Intracellular hydrogen peroxide concentration and superoxide release were also evaluated in neutrophils. A significant increase was observed in SOD and GPx amount and activity in patients with DS with and without CHD. No significant difference was found in the amount and activity of MPO and CAT among the different experimental groups. Intracellular hydrogen peroxide concentration was similar in all groups, whereas a prominent decrease was seen in superoxide release in cases with DS. Patients with DS with and without CHD showed no significant differences in any of the measured parameters. The data suggest that CHD observed in patients with DS does not result from altered redox metabolism associated with the disease.
Akinci
Ozlem
O
Department of Pediatric Genetics, Akdeniz University School of Medicine, Antalya, Turkey.
Mihci
Ercan
E
Tacoy
Sukran
S
Kardelen
Firat
F
Keser
Ibrahim
I
Aslan
Mutay
M
D000975:Antioxidants / Q000378:metabolism; D015153:Blotting, Western; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D002648:Child; D004314:Down Syndrome / Q000150:complications* / Q000201:enzymology* / Q000235:genetics; D005260:Female; D005979:Glutathione Peroxidase / Q000235:genetics / Q000378:metabolism; D006330:Heart Defects, Congenital / Q000209:etiology* / Q000235:genetics; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D008297:Male; D009504:Neutrophils / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism
D000975:Antioxidants; D006861:Hydrogen Peroxide; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase