Erythrocyte Acetylcholinesterase as a Biomarker of Environmental Lead Exposure

Lead is a prime, ubiquitous, environmental toxicant and multi-organ poison. One of the most recognized deleterious effects of lead exposure is neurotoxicity, which may at least in part arise from perturbation in cholinergic neurotransmission with possible impact on acetylcholinesterase activity. Although primarily located at the neuromuscular junction and cholinergic brain synapses, this pivotal enzyme is also present in peripheral cells such as human erythrocytes. Erythrocyte acetylcholinesterase, which correlates positively with brain acetylcholinesterase and represents neurotoxic targets in brain, is a conventional biomarker for the neurotoxic effects of pesticide exposure. However, recent reports have unveiled the sensitivity of this extra-neural enzyme to other environmental contaminants particularly lead, bringing to attention its relevance in the assessment of environmental lead exposure and lead-induced neurotoxicity. This chapter summarizes the evidence of the remarkable diversity of erythrocyte acetylcholinesterase as a biomarker of environmental lead exposure and lead-induced alterations in human cholinergic system as well as the possible factors surrounding its applicability in this regard.