MECHANISMS OF TOXIC INJURY IN VASCULAR TISSUE

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Our long-range goal is to clarify cellular events during vascular injury by toxic chemicals. Our continued focus on allylamine (AA)-metabolism to a toxic aldehyde, acrolein, that causes probable mitochondrial injury (and a later vascular proliferative response) will be augmented by studies of the mechanism of large vessel necrotizing injury in a new model of vascular toxic synergism (AA plus beta-aminopriopionitrile, or betaAPN). We will dissect early metabolic events occurring in vascular smooth muscle cells, weighing the contribution of acrolein's direct attack on cellular nucleophiles vs. the contribution of H2O2 and reactive oxygen species to toxicity. The potential role and mechanisms of injury to the proposed target organelle, mitochondria, will be examined. We will define altered growth and cell division characteristics of vascular (aortic, endothelial and medial) cells due to acute AA exposure in cells derived from rats treated in vivo with AA. We will characterize early response genes (c-myc, c-fos) heat shock proteins (HSP70) and expression of growth factors. We will define phenotypic changes induced acutely by AA (morphology, cytoskeleton, smooth muscle alpha-actin expression), and ascertain if inhibitors of AA metabolism will obviate these acute responses. To better understand synergistic toxicity, we will do a series of in vitro mechanistic experiments in cultured vascular smoothmuscle cells, their media, and reconstituted enzyme systems to assess the importance of SSAO in vascular damage, and assess the importance of acrolein, glutathione conjugates, adducts, and other toxic metabolites in damage which is proposed to be initiated through targeting of mitochondria. These studies will hopefully lead to an understanding of vascular metabolism, injury, and pathologic responses.