Is plasma β-glucuronidase a novel human biomarker for monitoring anticholinesterase pesticides exposure? A Malaysian experience

β-glucuronidase as a biomarker for assessing the exposure to anticholinergic pesticides: A meta-analysis

INTRODUCTION

The human exposure to anticholinergic pesticides has been associated with the development of various diseases. Therefore, several biomarkers have been proposed for biomonitoring human exposure to anticholinergic pesticides.

OBJECTIVE

This work evaluated the effect of human exposure to anticholinergic pesticides on β-glucuronidase (GUSB) levels.

METHODS

A systematic review was performed using PubMed, Web of Science, Scopus, and EBSCO databases up to December 2021. The statistical analysis employed standardized mean differences and meta-regression. And the trial sequential analysis was performed.

RESULTS

Nine studies were included. A monotonic relationship was observed between poisoning severity and GUSB. Furthermore, BuChE levels were correlated with GUSB levels.

CONCLUSIONS

The results indicated that GUSB levels could be used as a possible diagnosis biomarker in poisoning related to anticholinergic pesticide exposure. However, the use of GUSB to assess the chronic exposure to anticholinergic pesticides could be only performed in recent exposure (≈ 7 days after last exposure).

Biochemical responses as early and reliable biomarkers of organophosphate and carbamate pesticides intoxication: A systematic literature review

Inhibition of cholinesterase (ChE) activity has been long considered as the main diagnostic method of organophosphate (OP) and carbamate pesticides poisoning; however, it has been shown that ChE activity may also be altered due to exposure to other non-organophosphorus toxicants and variety of different medical conditions. Hence, to avoid misdiagnosis, we aimed to systematically review available documents to look for additional biomarkers of OP and carbamate poisoning. The electronic databases in addition to Google scholar were searched for eligible articles on March 2022 using "organophosphate," "carbamate," and "biomarker" including all their similar terms. After collecting the relevant documents, the data were extracted and described qualitatively. In total, data of 66 articles from 51 human and 15 animal studies were extracted. Findings demonstrated that enzymes such as β-glucuronidase, neuropathy target esterase, amylase, and lipase, in addition to hematological indicators such as CBC, CRP, lactate dehydrogenase, and CPK have high sensitivity and accuracy in the diagnosis of OP poisoning. Findings suggest that using various markers for diagnosis of OP intoxication is helpful for appropriate management, and early identifying the patients at risk of death. The suggested biomarkers also help to avoid misdiagnosis of OP poisoning with other similar conditions.

Organophosphorus pesticide exposure biomarkers in a Mexican population

The organophosphate (OP) pesticides are neurotoxic compounds widely used around the world. Evaluation of OP exposure in human studies is important for enabling adequate data analyses and drawing accurate conclusions. The aim of this study was to analyze OP exposure biomarkers and their relationships in a Mexican population with different exposure levels. Dialkylphosphates (DAP) were determined through gas chromatography-mass spectrometry (GC-MSD); acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), arylesterase (AREase), basal paraoxonase 1 (PONase), and β-glucuronidase activities were detected using spectrophotometric methods. The albumin content was determined in a certified clinical laboratory. The DMTP metabolite was found in the highest concentration, and a negative and significant correlation between DAP and cholinesterase activity was observed. Our results suggested that BuChE is a considerably more sensitive biomarker than AChE. In addition, β-glucuronidase was positively correlated with albumin, BuChE, and PONase. In conclusion, our data strongly support the use of two or more biomarkers of exposure in human monitoring and the application of a strong and validated questionnaire.

Therapeutic significance of β-glucuronidase activity and its inhibitors: A review

The emergence of disease and dearth of effective pharmacological agents on most therapeutic fronts, constitutes a major threat to global public health and man's existence. Consequently, this has created an exigency in the search for new drugs with improved clinical utility or means of potentiating available ones. To this end, accumulating empirical evidence supports molecular target therapy as a plausible egress and, β-glucuronidase (βGLU) - a lysosomal acid hydrolase responsible for the catalytic deconjugation of β-d-glucuronides has emerged as a viable molecular target for several therapeutic applications. The enzyme's activity level in body fluids is also deemed a potential biomarker for the diagnosis of some pathological conditions. Moreover, due to its role in colon carcinogenesis and certain drug-induced dose-limiting toxicities, the development of potent inhibitors of βGLU in human intestinal microbiota has aroused increased attention over the years. Nevertheless, although our literature survey revealed both natural products and synthetic scaffolds as potential inhibitors of the enzyme, only few of these have found clinical utility, albeit with moderate to poor pharmacokinetic profile. Hence, in this review we present a compendium of exploits in the present millennium directed towards the inhibition of βGLU. The aim is to proffer a platform on which new scaffolds can be modelled for improved βGLU inhibitory potency and the development of new therapeutic agents in consequential.

Serum β-glucuronidase activity as a biomarker for acute cholinesterase inhibitor pesticide poisoning

β-glucuronidase (BG) activity is a promising biomarker for diagnosis and prognosis after exposure to organophosphorous (OP) pesticides. The aim of this study was to evaluate the changes in serum BG activity in patients with acute OP poisoning and to determine whether these changes correlate with the severity of poisoning. Thirty patients with anticholinesterase pesticide poisoning were included, besides 10 healthy volunteers as a control group. Serum activities of butyrylcholinesterase (BuChE) and BG were measured for each subject on admission, then after 12 and 24 h. Serum levels of BuChE and BG in poisoned patients were significantly different from the control subjects; these differences persisted in repeated measurements. Moreover, the serum levels showed significant differences within each group of the three time points. A significant negative correlation was found between the serum activities of BuChE and BG in all groups at the three time points. In conclusion, serum BG activity seems a reliable marker for OP poisoning even when measured at 24 h after poisoning.

Blood β-glucuronidase as a suitable biomarker at acute exposure of severe organophosphorus poisoning in human

Organophosphorus compounds are known to cause the selective release of liver microsomal β-glucuronidase into plasma. Organophophoruses may induce nitrosative stress leading to the generation of nitrogen free radicals and alterations in scavengers of free radicals in many biological systems. In this study, we investigate how acute human organophosphorus intoxication is associated with changes of blood nitric oxide, total thiol molecules, and activities of the acetylcholinesterase and β-glucuronidase. A total of 21 acute organophosphorus-poisoned patients were recruited into study and were divided into two groups of mildly (13) and severely affected (9); 26 age-matched healthy volunteers were recruited as control group. Results indicated that both mildly and severely affected patients had lower acetylcholinesterase activities as compared to controls. The extent of acetylcholinesterase reduction in the severely affected patients was higher than that of mildly affected patients. A significant increase in serum β-glucuronidase was observed only in severely affected patients as compared to controls. Both mildly and severely affected patients had lower plasma total thiol molecules as compared to controls. The extent of reduction of total thiol molecules in the severely affected patients was higher than that of mildly affected patients. No significant difference was observed in plasma total nitric oxide of controls and patients. It is concluded that nitrosative stress has a minor role in toxicity of organophosphorus, whereas blood β-glucuronidase is very sensitive biomarker at high exposure of severe organophosphorus poisoning.

Environmental exposure to organophosphate pesticides: assessment of endocrine disruption and hepatotoxicity in pregnant women

In utero exposure is the first point of contact with environmental xenobiotics that may affect the maternal-placental-fetal balance. Considering that maternal pathophysiological changes affect intrauterine development, this pilot study was conducted to address how environmental exposure to organophosphate pesticides (OPs) during pregnancy may contribute to maternal endocrine disruption and disturbed hepatic function. A prospective study was carried out with pregnant women (n=97) living in a rural area of the Rio Negro province where OPs are intensively applied throughout 6 months of the year. Blood samples were obtained and biomarkers of OPs exposure (cholinesterases and β-glucuronidase), cortisol (CT) and progesterone (PG) levels, as well as glycemia, were determined. Parameters of liver injury were assayed by measuring aspartate aminotransferase (AST) and alanine aminotransferase (ALT); liver function was assayed by measuring albumin. Biomonitoring carried out during the pre-spraying period (PreS) and spraying period (SP) showed that the population studied was exposed to OPs, proven by the fact that plasma (PCh) and erythrocyte cholinesterase (AChE) decreased very significantly (p<0.01) during SP. CT values increased very significantly (p<0.01) in the first trimester of pregnancy during SP with respect to PreS. Individual values above the upper limit of the CT and PG reference range were found both in PreS and SP. This finding could be associated with changes in hormone metabolism pathways produced by OPs exposure. During the second trimester of pregnancy there were increases in ALT values and the AST/ALT ratio in SP, suggesting subclinical hepatotoxicity. In SP, glycemia was unchanged while albuminemia increased. Although anthropometric newborn parameters and pregnancy alterations were within normal values for the general population, the increase in CT in the maternal compartment may lead to impaired newborn health later in life.

Is beta-glucuronidase a clinical useful biomarker for an acute organophosphorus poisoning?

beta-glucuronidase is considered a sensitive biomarker for acute organophosphorus poisoning. In this well-documented study, multiple plasma samples over time were collected. A decrease in plasma concentration of beta-glucuronidase was surprisingly observed, even within normal range. These findings do not support the hypothesis that beta-glucuronidase is a useful biomarker for acute organophosphorus poisoning in humans.