Serum ubiquitin C-terminal hydrolase L1 predicts cognitive impairment in patients with acute organophosphorus pesticide poisoning

Organophosphorus Nerve Agents: Types, Toxicity, and Treatments

Organophosphorus compounds are extensively used worldwide as pesticides which cause great hazards to human health. Nerve agents, a subcategory of the organophosphorus compounds, have been produced and used during wars, and they have also been used in terrorist activities. These compounds possess physiological threats by interacting and inhibiting acetylcholinesterase enzyme which leads to the cholinergic crisis. After a general introduction, this review elucidates the mechanisms underlying cholinergic and noncholinergic effects of organophosphorus compounds. The conceivable treatment strategies for organophosphate poisoning are different types of bioscavengers which include stoichiometric, catalytic, and pseudocatalytic. The current research on the promising treatments specifically the catalytic bioscavengers including several wild-type organophosphate hydrolases such as paraoxonase and phosphotriesterase, phosphotriesterase-like lactonase, methyl parathion hydrolase, organophosphate acid anhydrolase, diisopropyl fluorophosphatase, human triphosphate nucleotidohydrolase, and senescence marker protein has been widely discussed. Organophosphorus compounds are reported to be the nonphysiological substrate for many mammalian organophosphate hydrolysing enzymes; therefore, the efficiency of these enzymes toward these compounds is inadequate. Hence, studies have been conducted to create mutants with an enhanced rate of hydrolysis and high specificity. Several mutants have been created by applying directed molecular evolution and/or targeted mutagenesis, and catalytic efficiency has been characterized. Generally, organophosphorus compounds are chiral in nature. The development of mutant enzymes for providing superior stereoselective degradation of toxic organophosphorus compounds has also been widely accounted for in this review. Existing enzymes have shown limited efficiency; hence, more effective treatment strategies have also been critically analyzed.

Serum ubiquitin C-terminal hydrolase L1 predicts cognitive impairment in patients with acute organophosphorus pesticide poisoning

BACKGROUND

To assess the usefulness of serum C-terminal hydrolase L1 (UCH-L1) level as a biomarker for predicting cognitive impairment in patients with acute organophosphorus pesticide poisoning (AOPP).

METHODS

Two hundred and seven adult patients with AOPP were included in this study. Serum UCH-L1 levels were assessed on admission (Day 1 postpoisoning) and on Days 3 and 7 postpoisoning. The associations between serum UCH-L1 levels, other clinical predictors, and cognitive function evaluated on Day 30 postpoisoning were investigated.

RESULTS

On multivariate analysis, serum UCH-L1 levels on admission (odds ratio [OR] 1.889, 95% confidence interval [CI] 1.609-3.082, P = 0.002) and 24-hour APACHE II score (OR 1.736, 95% CI 1.264-3.272, P = 0.012) were independent predictors of cognitive impairment on Day 30 postpoisoning. Based on the receiver operating characteristic curve, serum UCH-L1 levels >5.9 ng/mL on admission predicted cognitive impairment on Day 30 postpoisoning with 86.1% sensitivity and 72.5% specificity (area under the curve, 0.869; 95% CI 0.815-0.923). On admission [8.51 (6.53-10.22) ng/mL vs 4.25 (2.57-6.31) ng/mL, P < 0.001] and Day 3 [9.31 (7.92-10.98) ng/mL vs 3.32 (2.25-5.13) ng/mL, P < 0.001] and Day 7 [4.96 (3.28-7.26) ng/mL vs 2.27 (1.55-3.24) ng/mL, P < 0.001] postpoisoning, serum UCH-L1 concentration was significantly higher in patients that developed cognitive impairment compared to those that did not.

CONCLUSION

This study demonstrates that serum UCH-L1 level has potential as a novel biomarker for predicting cognitive impairment 30 days after AOPP.