Aldehyde load in ischemia–reperfusion brain injury: Neuroprotection by neutralization of reactive aldehydes with phenelzine

• Published in: Brain research 2006-11, Vol.1122 (1), p.184-190
• Main Authors: Wood, Paul L., Khan, M. Amin, Moskal, Joseph R., Todd, Kathryn G., Tanay, Véronique A.M.I., Baker, Glen
• Format: Article
• Language: English
• Subjects: 3-Aminopropanal; Acrolein; Acrolein - metabolism; Acrolein - toxicity; Aldehyde sequestration; Aldehydes - metabolism; Aldehydes - toxicity; Animals; Biological and medical sciences; Brain - drug effects; Brain - enzymology; Brain - pathology; Brain Ischemia - drug therapy; Brain Ischemia - enzymology; Brain Ischemia - pathology; Cells, Cultured; Disease Models, Animal; Gerbillinae; Global ischemia; Male; Medical sciences; Mercaptopropionylglycine; Monoamine Oxidase Inhibitors - pharmacology; Neurology; Neuropharmacology; Neuroprotection; Neuroprotective Agents - pharmacology; Pharmacology. Drug treatments; Phenelzine; Phenelzine - pharmacology; Propylamines - metabolism; Propylamines - toxicity; Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease); Psychology. Psychoanalysis. Psychiatry; Psychopharmacology; Rats; Reperfusion Injury - enzymology; Reperfusion Injury - prevention & control; Retina - cytology; Retinal Ganglion Cells - drug effects; Retinal Ganglion Cells - enzymology; Time Factors; Vascular diseases and vascular malformations of the nervous system
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2006.09.003

In ongoing studies of the neuroprotective properties of monoamine oxidase inhibitors, we found that phenelzine provided robust neuroprotection in the gerbil model of transient forebrain ischemia, with drug administration delayed up to 3 h post reperfusion. Since ischemia–reperfusion brain injury is associated with large increases in the concentrations of reactive aldehydes in the penumbra area, we investigated if the hydrazine function of phenelzine was capable of sequestering reactive aldehydes. Both aminoaldehydes and acrolein are generated from the metabolism of polyamines to putrescine by polyamine oxidase. These toxic aldehydes in turn compromise mitochondrial and lysosomal integrity and initiate apoptosis and necrosis. Previous studies have demonstrated that pharmacological neutralization of reactive aldehydes via the formation of thioacetal derivatives results in significant neuroprotection in ischemia–reperfusion injury, in both focal and global ischemia models. In our studies of acrolein and 3-aminopropanal toxicity, using an immortalized retinal cell line, we found that aldehyde sequestration with phenelzine was neuroprotective. The neuroprotection observed with phenelzine is in agreement with previous studies of aldehyde sequestering agents in the treatment of ischemia–reperfusion brain injury and supports the concept that “aldehyde load” is a major factor in the delayed cell losses of the ischemic penumbra.