DRAMATIC INCREASE OF ALPHA-HYDROXYALDEHYDES DERIVED FROM PLASMALOGENSIN THE AGED HUMAN BRAIN

Plasmalogens-substantial compounds of brain tissue-suffer degradation either by hydrolysis under production of aldehydes or by oxidation wit h lipid peroxylradicals by generation of plasmalogen epoxides. The lat ter react by addition of pentafluorobenzylhydroxylamine . HCl (PFBHA . HCL) under hydrolysis to alpha-hydroxyaldehydes which are immediately transformed to pentafluorobenzyloximes (PFBO). Likewise, free aldehyd es are transformed to PFBO-derivatives. PFBO-derivatives of free aldeh ydes and PFBO-derivatives of alpha-hydroxyaldehydes were extracted and after trimethylsilylation quantified by GC/FID and by GC/MSD. The rem aining aqueous phase, containing plasmalogens besides other lipids, wa s hydrolyzed by treatment with acid. The hydrolysis products of plasma logens, long chain aldehydes, react with PFBHA . HCl to produce PFBO-d erivatives. These were also quantified by GC/FID. This method allows t he quantification of plasmalogens, free aldehydes and plasmalogenepoxi des in human brain samples to study changes in the relation of these c ompounds with increasing age. While the ratio of plasmalogens in respe ct to derived aldehydes seems to remain constant during life time, the quotient of plasmalogenepoxides to plasmalogens increases with age, i ndicating that lipid peroxidation processes are involved in the damage of plasmalogens in the brain of aged individuals, starting at an age of about 70 years. (C) 1997 Elsevier Science Ireland Ltd.