title: Methionine challenge paradoxically induces a greater activation of the antioxidant defence in subjects with hyper- vs. normohomocysteinemia.
abstract: To determine whether hyperhomocysteinemia induced post-methionine loading (PML) is associated with different response in the aminothiol redox state and oxidative stress vs. normohomocysteinemia, we assessed PML plasma thiols, vitamins, free malondialdehyde (MDA), and blood reduced glutathione (GSH) in 120 consecutive subjects (50 [35-56] years, 83 males), divided into two groups according to PML plasma total Hcy < 35 microM (Group 1, n = 65) or > or = 35 microM (Group 2, n = 55). In the group as a whole, plasma reduced cysteine and cysteinylglycine, blood reduced GSH (all p for time = 0.0001) and plasma total GSH (p for time = 0.001) increased from baseline to PML. MDA values were unchanged. Group 1 and 2 differed in blood reduced GSH (p for group = 0.004, higher in Group 2), and MDA levels (p for group = 0.024, lower in Group 2). The oxidative stress induced by methionine challenge seems to be opposed by scavenger molecules activation, namely GSH, and lipid peroxidation does not increase. This mechanism paradoxically appears to be more efficient in hyperhomocysteinemic subjects.
authors.affiliation: CNR Clinical Physiology Institute, Niguarda Ca' Granda Hospital, Cardiology Department, Milan, Italy.
authors.forename: Jonica
authors.initials: J
authors.lastname: Campolo
authors.forename: Benedetta
authors.initials: B
authors.lastname: De Chiara
authors.forename: Raffaele
authors.initials: R
authors.lastname: Caruso
authors.forename: Renata
authors.initials: R
authors.lastname: De Maria
authors.forename: Valentina
authors.initials: V
authors.lastname: Sedda
authors.forename: Cinzia
authors.initials: C
authors.lastname: Dellanoce
authors.forename: Marina
authors.initials: M
authors.lastname: Parolini
authors.forename: Giuliana
authors.initials: G
authors.lastname: Cighetti
authors.forename: Silvana
authors.initials: S
authors.lastname: Penco
authors.forename: Francesco
authors.initials: F
authors.lastname: Baudo
authors.forename: Oberdan
authors.initials: O
authors.lastname: Parodi
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000378:metabolism*; D005260:Female; D005978:Glutathione / Q000097:blood; D006801:Humans; D020138:Hyperhomocysteinemia / Q000097:blood / Q000175:diagnosis* / Q000378:metabolism*; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008715:Methionine / Q000008:administration & dosage; D008875:Middle Aged; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology; D013438:Sulfhydryl Compounds / Q000097:blood; D014815:Vitamins / Q000097:blood
chemical_list: D000975:Antioxidants; D013438:Sulfhydryl Compounds; D014815:Vitamins; D008315:Malondialdehyde; D008715:Methionine; D005978:Glutathione