Developmental Lag in Superoxide Dismutases Relative to Other Antioxidant Enzymes in Premyelinated Human Telencephalic White Matter

• Published in: Journal of neuropathology and experimental neurology 2004-09, Vol.63 (9), p.990-999
• Main Authors: FOLKERTH, REBECCA D, HAYNES, ROBIN L, BORENSTEIN, NATALIA S, BELLIVEAU, RICHARD A, TRACHTENBERG, FELICIA, ROSENBERG, PAUL A, VOLPE, JOSEPH J, KINNEY, HANNAH C
• Format: Article
• Language: English
• Subjects: Aged; Antioxidants - metabolism; Astrocytes - enzymology; Biological and medical sciences; Catalase - metabolism; Cerebral Palsy - enzymology; Cerebral Palsy - etiology; Cerebral Palsy - prevention & control; Child, Preschool; Female; Free Radicals - metabolism; Glutathione Peroxidase - metabolism; Humans; Immunity, Innate - physiology; Infant; Infant, Newborn; Leukomalacia, Periventricular - enzymology; Leukomalacia, Periventricular - etiology; Leukomalacia, Periventricular - physiopathology; Lipid Peroxidation - physiology; Medical sciences; Middle Aged; Myelin Sheath - enzymology; Nerve Fibers, Myelinated - enzymology; Nerve Fibers, Myelinated - pathology; Neurology; Obstetric Labor, Premature - complications; Oligodendroglia - enzymology; Oxidative Stress - physiology; Pregnancy; Reperfusion Injury - enzymology; Reperfusion Injury - etiology; Reperfusion Injury - physiopathology; Superoxide Dismutase - metabolism; Telencephalon - embryology; Telencephalon - enzymology; Telencephalon - growth & development
• ISSN: 0022-3069; 1554-6578
• DOI: 10.1093/jnen/63.9.990

Periventricular leukomalacia (PVL) involves free radical injury to developing oligodendrocytes (OLs), resulting from ischemia/reperfusion, particularly between 24 and 32 gestational weeks. Using immunocytochemistry and Western blots, we tested the hypothesis that this vulnerability to free radical toxicity results, in part, from developmental lack of superoxide dismutases (SOD)-1 and -2, catalase, and glutathione peroxidase (GPx) in the telencephalic white matter of the human fetus. During the period of greatest PVL risk and through term (≥37 weeks), expression of both SODs (for conversion of O2 to H2O2) significantly lagged behind that of catalase and GPx (for breakdown of H2O2), which, in contrast, superseded adult levels by 30 gestational weeks. Our data indicate that a developmental “mismatch” in the sequential antioxidant enzyme cascade likely contributes to the vulnerability to free radical toxicity of the immature cerebral white matter, which is “unprepared” for the transition from a hypoxic intrauterine to an oxygen-rich postnatal environment. All enzymes, localized to astrocytes and OLs, had higher-than-adult expression at 2 to 5 postnatal months (peak of myelin sheath synthesis), suggesting an adaptive mechanism to protect against lipid peroxidation during myelin sheath (lipid) synthesis. The previously unrecognized dissociation between the expression of the SODs and that of catalase and GPx in the fetal period has potential implications for future antioxidant therapy in PVL.