title: Experimental evidence of oxidative stress in plasma of homocystinuric patients: a possible role for homocysteine.
abstract: Homocystinuria is an inherited disorder biochemically characterized by high urinary excretion of homocystine and increased levels of homocysteine (Hcy) and methionine in biological fluids. Affected patients usually have a variety of clinical and pathologic manifestations. Previous experimental data have shown a relationship between Hcy and oxidative stress, although very little was reported on this process in patients with homocystinuria. Therefore, in the present study we evaluated parameters of oxidative stress, namely carbonyl formation, malondialdehyde (MDA) levels, sulfhydryl content and total antioxidant status (TAS) in patients with homocystinuria at diagnosis and under treatment with a protein restricted diet supplemented by pyridoxine, folate, betaine, and vitamin B(12). We also correlated plasma Hcy and methionine concentrations with the oxidative stress parameters examined. We found a significant increase of MDA levels and carbonyl formation, as well as a reduction of sulfhydryl groups and TAS in plasma of homocystinuric patients at diagnosis relatively to healthy individuals (controls). We also verified that Hcy levels were negatively correlated with sulfhydryl content and positively with MDA levels. Furthermore, patients under treatment presented a significant reduction of the content of MDA, Hcy and methionine concentrations relatively to patients at diagnosis. Taken together, the present data indicate that lipid and protein oxidative damages are increased and the antioxidant defenses diminished in plasma of homocystinuric patients, probably due to increased reactive species elicited by Hcy. It is therefore presumed that oxidative stress participates at least in part in the pathogenesis of homocystinuria.
authors: Programa de Pós-Graduação em Ciências Biológicas:Bioquímica da Universidade Federal do Rio Grande do Sul (UFRGS), Ramiro Barcelos 2700, Porto Alegre, RS, 90035-000, Brazil.
authors: Camila Simioni
authors: CS
authors: Vanzin
authors: Giovana Brondani
authors: GB
authors: Biancini
authors: Angela
authors: A
authors: Sitta
authors: Carlos Alberto Yasin
authors: CA
authors: Wayhs
authors: Izabela Netto
authors: IN
authors: Pereira
authors: Francieli
authors: F
authors: Rockenbach
authors: Solange Cristina
authors: SC
authors: Garcia
authors: Angela Terezinha de Souza
authors: AT
authors: Wyse
authors: Ida Vanessa Doederlein
authors: IV
authors: Schwartz
authors: Moacir
authors: M
authors: Wajner
authors: Carmen Regla
authors: CR
authors: Vargas
mesh_terms: D000293:Adolescent; D000328:Adult; D000975:Antioxidants / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006712:Homocystinuria / Q000097:blood* / Q000473:pathology*; D006801:Humans; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D018384:Oxidative Stress; D050050:Protein Carbonylation; D013438:Sulfhydryl Compounds / Q000097:blood; D055815:Young Adult
chemical_list: D000975:Antioxidants; D013438:Sulfhydryl Compounds; D006710:Homocysteine; D008315:Malondialdehyde