Erythrocyte acetylcholinesterase as biomarker of pesticide exposure: new and forgotten insights

Abstract

Acetylcholinesterase (AChE) acts on the hydrolysis of acetylcholine, rapidly removing this neurotransmitter at cholinergic synapses and neuromuscular junctions as well as in neuronal growth and differentiation, modulation of cell adhesion ("electrotactins") and aryl-acylamidase activity (AAA). This enzyme is also found in erythrocyte, as 160 kDa dimer that anchors to the plasma membrane via glycophosphatidylinositol. The function of this enzyme in erythrocytes has not yet been elucidated; however, it is suspected to participate in cell-to-cell interactions. Here, a review on erythrocyte AChE characteristics and use as biomarker for organophosphorus and carbamate insecticides is presented since it is the first specific target/barrier of the action of these pesticides, besides plasma butyrylcholinesterase (BChE). However, some past and current methods have disadvantages: (a) not discriminating the activities of AChE and BChE; (b) low accuracy due to interference of hemoglobin in whole blood samples. On the other hand, extraction methods of hemoglobin-free erythrocyte AChE allows: (a) the freezing and transporting of samples; (b) samples free of colorimetric interference; (c) data from only erythrocyte AChE activity; (d) erythrocyte AChE specific activity presents higher correlation with the central nervous system AChE than other peripheral ChEs; (e) slow spontaneous regeneration against anti-ChEs agents of AChE in comparison to BChE, thus increasing the chances of detecting such compounds following longer interval after exposure. As monitoring perspectives, hemoglobin-free methodologies may be promising alternatives to assess the degree of exposure since they are not influenced by this interfering agent.

Monitoring Blood Cholinesterase Activity of Farmworkers: In Vitro Inhibition by Diphenhydramine and Carbaryl

“…It is also possible that the exposure of the participants to pesticides was gradual and limited to small levels (doses) since the exposed subjects did not suffer from exposure-related overt ill effects usually seen in acute antiChE poisoning (Cocker et al, 2002;Wilson et al, 2005;Lionetto et al, 2013;Wilson, 2014;Vale & Lotti, 2015). In this context, it should be stressed that antiChE pesticides possess differential ChE inhibitory actions on the plasma and erythrocytes (Roy et al, 2005;Wilson et al, 2005;Lionetto et al, 2013;Wilson, 2014;Cotton et al, 2018;Hongsibsong et al, 2018;Assis et al, 2018). However, inhibition of plasma ChE activity strongly correlates with the intensity and duration of exposure to pesticides (He, 1999;Lionetto et al, 2013).…”

Blood cholinesterase activities and oxidative stress status among farmworkers using pesticides in Duhok, KRG, Iraq

“…A single study conducted in Duhok found 14.0% and 4.0% reductions in PChE and EChE activities, respectively, in pesticide-exposed farmworkers in comparison to unexposed ones [20]. Pesticide exposure of agricultural workers and those involved in handling and dispensing pesticides can be monitored biologically by examining PChE or EChE activities [8, [20][21][22], monitoring oxidative status such as plasma malondialdehyde (MDA) [8,23], as well as by analysis of concentrations of pesticides or their metabolites in human biological samples [24]. The studies which have been conducted in Iraq [16][17][18]20] suggested a marginal blood ChE inhibition, though important from a risk assessment point of view.…”

Hubungan Faktor Okupasi terhadap Aktivitas Asetilkolinesterase Eritrosit dan Fungsi Kognitif pada Petani yang Menggunakan Pestisida Organofosfat

“…Hasil dari penelitian-penelitian sebelumnya menyimpulkan bahwa penggunaan pestisida organofosfat di luar standar pemakaian akan menyebabkan keracunan dan gangguan sistem pada tubuh manusia. 2 Organofosfat merupakan jenis pestisida yang paling banyak digunakan hampir di seluruh dunia terutama di sektor pertanian dan perkebunan sebagai salah satu cara memberantas hama. Sebagai substansi kimia, pestisida memberikan efek toksik bagi manusia yang terpapar.…”