The potential application of human PIG‐A assay on azathioprine‐treated inflammatory bowel disease patients

Abstract

The rodent Pig-a assay has been used extensively as a potential regulatory assay for evaluating the in vivo mutagenicity of test substances. Although the assay can be conducted in different mammalian species, there have been only a few reports describing its use in humans, and rarely in genotoxicant-exposed human populations. In this study, PIG-A mutation frequencies (MFs) were evaluated in 36 azathioprine (AZA; human carcinogen)-treated inflammatory bowel disease (IBD) patients and 36 healthy volunteers. IBD patients exhibited a slight but statistically higher MF (6.10 AE 4.44 × 10 −6 ) than healthy volunteers (4.97 AE 2.74 × 10 −6 ) (P = 0.0489). The estimated relative risk for the exposed patients was 1.22 which indicated that AZA is a risk factor for inducing PIG-A mutation. However, the PIG-A MF showed no associations with AZA treatment duration or total AZA exposure. In addition, we performed the cytokinesis-block micronucleus test on the same samples. The frequencies of micronuclei (MN) and nuclear buds (NBUD) in IBD patients (MN: 4.70 AE 2.86‰; NBUD: 1.89 AE 0.95‰) were significantly higher than in healthy volunteers (MN: 1.47 AE 0.77‰, P < 0.001; NBUD: 0.90 AE 0.58‰, P = 0.004). MN frequency also had significant correlations with AZA treatment duration (P = 0.011) and total AZA exposure (P = 0.018).Our findings indicate that AZA-treated IBD patients have only a marginally significant increase in PIG-A MF; in contrast, a much stronger AZA-associated increase in genotoxicity was detected with the lymphocyte MN assay. Environ. Mol. Mutagen. 61:456-464, 2020.

Assessment of systemic genetic damage in pediatric inflammatory bowel disease

“…Recently, Cao et al (2020) reported a slight increase in mutant phenotype erythrocytes in Chinese IBD patients. Two differences between these studies are noteworthy, and one is related to methodology.…”

“…Since genomic damage is recognized as playing a key role in the multistep process of carcinogenesis, this work suggested that IBD itself (at least in several mouse models) may be responsible for some portion of the elevated risk of hematopoietic cancers. More recently, Cao et al (2020) extended the study of genotoxicity biomarkers from laboratory rodent models to IBD patients in China. They found that adult IBD patients exhibited markedly higher micronucleated lymphocyte frequencies compared to an age-matched healthy adult population.…”

“…More recently, Cao et al . (2020) extended the study of genotoxicity biomarkers from laboratory rodent models to IBD patients in China. They found that adult IBD patients exhibited markedly higher micronucleated lymphocyte frequencies compared to an age‐matched healthy adult population.…”

Human blood PIG‐A mutation and micronucleated reticulocyte flow cytometric assays: Method optimization and evaluation of intra‐ and inter‐subject variation

“…This laboratory and others have previously reported significant progress adapting these rodent assays to human blood analyses (Dertinger et al ., 2004, 2007, 2015; Grawé et al ., 2005; Offer et al ., 2005; Witt et al ., 2007; Dobrovolsky et al ., 2011; Cao et al ., 2016, 2020a, 2020b; Horibata et al ., 2016; Khattab et al ., 2017; Haboubi et al ., 2019). Here, we report methodological improvements that overcome barriers to wide‐spread use.…”

Evaluation ofPIG‐A‐mutated granulocytes and ex‐vivo binucleated micronucleated lymphocytes frequencies after breast cancer radiotherapy in humans

“…Until recently, genetic toxicology tests and methods of human gene mutation detection were not suitable for human biomonitoring studies. However, in the last months, PIG‐A gene mutation has been used as a genotoxicity biomarker in various exposure scenarios in humans, in combination with the formation of micronuclei (Cao et al ., 2020a, 2020b). Moreover, optimized protocols related to human blood PIG‐A mutation and micronucleated reticulocyte flow cytometric assays have been published (Torous et al ., 2020).…”