Key result
Exposure to substances causing transient uteroplacental hypoperfusion induces limb and CNS malformations in animal models, likely mediated by reactive oxygen and nitrogen species.
The study proposes a role for reactive oxygen and nitrogen species in the genesis of limb reduction defects during fetal development.
May implicate oxidative stress in human limb defects; leaves open translation from animal models to clinical relevance.
Shepard and Mackler have documented quantitative increases in mitochondrial cristae between gestational days 10 and 14 in rats accompanied by decreased glucose utilization and increased NADH oxidase activity. Findings show a shift from glycolytic to oxidative metabolism starting at around the time of implantation. Exposure to many substances that cause transient uteroplacental hypoperfusion, including cocaine, phenytoin, calcium channel blockers, and nitric oxide synthase (NOS) inhibitors, induce limb and central nervous system (CNS) malformations while sparing the heart. We have reported that isolated electron transport particles prepared from sensitive tissues show reduced NADH oxidase activities compared with insensitive heart. They also have significantly greater superoxide formation in association with significantly reduced superoxide dismutase activities. NOS inhibitors induce severe limb reductions in late gestation. Exposure is associated with hemorrhage and nitrotyrosine (NT) formation shortly after treatment. Hemorrhage, malformations, and NT formation can be significantly reduced by coadministration of PBN, allopurinol, or aminoguanidine. On the basis of these findings, we have proposed a role for the formation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the genesis of limb reduction defects. It is important to note that limb reduction defects occur in humans ( approximately 0.22/1000) and have been associated with the agents listed above.
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Fantel et al. (2002) conducted a review in Fetal development and limb reduction defects. Substances causing transient uteroplacental hypoperfusion (e.g., cocaine, phenytoin, calcium channel blockers, NOS inhibitors) was evaluated on Limb and CNS malformations. Exposure to substances causing transient uteroplacental hypoperfusion induces limb and CNS malformations in animal models, likely mediated by reactive oxygen and nitrogen species.
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