A nonlinear dosimetric model for hemoglobin adduct formation by the neurotoxic agent acrylamide and its genotoxic metabolite glycidamide

High fried food consumption impacts anxiety and depression due to lipid metabolism disturbance and neuroinflammation

Western dietary patterns have been unfavorably linked with mental health. However, the long-term effects of habitual fried food consumption on anxiety and depression and underlying mechanisms remain unclear. Our population-based study with 140,728 people revealed that frequent fried food consumption, especially fried potato consumption, is strongly associated with 12% and 7% higher risk of anxiety and depression, respectively. The associations were more pronounced among male and younger consumers. Consistently, long-term exposure to acrylamide, a representative food processing contaminant in fried products, exacerbates scototaxis and thigmotaxis, and further impairs exploration ability and sociality of adult zebrafish, showing anxiety- and depressive-like behaviors. Moreover, treatment with acrylamide significantly down-regulates the gene expression of tjp2a related to the permeability of blood-brain barrier. Multiomics analysis showed that chronic exposure to acrylamide induces cerebral lipid metabolism disturbance and neuroinflammation. PPAR signaling pathway mediates acrylamide-induced lipid metabolism disorder in the brain of zebrafish. Especially, chronic exposure to acrylamide dysregulates sphingolipid and phospholipid metabolism, which plays important roles in the development of anxiety and depression symptoms. In addition, acrylamide promotes lipid peroxidation and oxidation stress, which participate in cerebral neuroinflammation. Acrylamide dramatically increases the markers of lipid peroxidation, including (±)5-HETE, 11(S)-HETE, 5-oxoETE, and up-regulates the expression of proinflammatory lipid mediators such as (±)12-HETE and 14(S)-HDHA, indicating elevated cerebral inflammatory status after chronic exposure to acrylamide. Together, these results both epidemiologically and mechanistically provide strong evidence to unravel the mechanism of acrylamide-triggered anxiety and depression, and highlight the significance of reducing fried food consumption for mental health.

Associations of acrylamide with non-alcoholic fatty liver disease in American adults: a nationwide cross-sectional study

BACKGROUND

Acrylamide (AA) is a toxicant to humans, but the association between AA exposure and the risk of non-alcoholic fatty liver disease (NAFLD) remains unclear. In this study, our objective is to examine the cross-sectional association between AA exposure and the risk of NAFLD in American adults.

METHODS

A total of 3234 individuals who took part in the National Health and Nutrition Examination Survey (NHANES) 2003-2006 and 2013-2016 were enrolled in the study. NAFLD was diagnosed by the U.S. Fatty Liver Index. Multivariable logistic regression models were applied to estimate the association between AA and NAFLD in the whole group and the non-smoking group.

RESULTS

We discovered that in the whole group, serum hemoglobin adducts of AA (HbAA) were negatively associated with the prevalence of NAFLD after adjustment for various covariables (P for trend < 0.001). Compared with individuals in the lowest HbAA quartiles, the odds ratios (ORs) with 95% confidence intervals (CIs) in the highest HbAA quartiles were 0.61 (0.46-0.81) and 0.57 (0.36-0.88) in the whole group and the non-smoking group, respectively. In contrast, HbGA/HbAA showed a significantly positive correlation with the prevalence of NAFLD in both groups (P for trend < 0.001). In addition, HbGA was not significantly associated with NAFLD in the whole group or the non-smoking group.

CONCLUSIONS

HbAA is negatively associated with NAFLD whereas HbGA/HbAA is positively associated with NAFLD in adults in the U.S. Further studies are needed to clarify these relationships.

Exposure to acrylamide and the risk of cardiovascular diseases in the National Health and Nutrition Examination Survey 2003-2006

BACKGROUND

Long-term exposure to acrylamide (AA) from diet sources may induce oxidative stress and chronic inflammation. However, the association between AA exposure and the prevalence of cardiovascular diseases (CVD) remains unclear.

OBJECTIVES

We aimed to examine the association between blood exposure levels of AA biomarkers and the prevalence of main types of CVD in a general population of US adults.

METHODS

We analyzed the associations between AA hemoglobin biomarkers [hemoglobin adducts of acrylamide (HbAA) and glycidamide (HbGA), sum of HbAA and HbGA (HbAA+HbGA), and ratio of HbGA to HbAA (HbGA:HbAA)] and self-reported diagnosis of CVD in 8290 adults (≥20 years of age) from the National Health and Nutrition Examination Survey (NHANES) 2003-2006. Multivariable logistic regression models were employed for estimating the associations in three groups classified by the combination of smoking status and serum cotinine levels.

RESULTS

In people exposed to environmental tobacco smoke (n = 4670), HbGA, HbAA+HbGA, and HbGA:HbAA were significantly and inversely associated with the prevalence of total CVD (p < 0.0001, p = 0.0155, and p = 0.0014 for trend, respectively) after adjusting for various covariates. The odd ratios (ORs) for total CVD in the highest quartiles of HbGA, HbAA+HbGA, and HbGA:HbAA were 0.311 [95% confidence interval (CI): 0.193-0.500], 0.664 (95% CI: 0.485-0.911), and 0.495 (95% CI: 0.326-0.752) when compared with the individual lowest quartiles. In active smokers (n = 2432), HbAA was positively associated with CVD risk (p = 0.0088 for trend), while HbGA:HbAA was inversely related to total CVD (p = 0.0137 for trend). However, no significant associations of any AA hemoglobin biomarker with total and individual CVD prevalence were observed in the nonsmoking group (n = 1188).

CONCLUSIONS

AA hemoglobin biomarkers are significantly associated with CVD in the active smoking group and the group exposed to environmental tobacco smoke but not in the nonsmoking group. Further prospective studies should clarify the causal relationship between HbAA and HbGA and the prevalence of CVD.

Dosimetry of Acrylamide and Glycidamide Over the Lifespan in a 2-Year Bioassay of Acrylamide in Wistar Han Rats

Acrylamide is an industrial chemical used to manufacture polymers, and is produced in foods during cooking at high heat. Hemoglobin adducts provide a long-lived dosimeter for acrylamide and glycidamide. This study determined acrylamide and glycidamide hemoglobin adducts (AAVal and GAVal) during a lifetime carcinogenesis bioassay. Exposure to acrylamide in drinking water began in utero in pregnant rats on gestation day 6. Dams were administered acrylamide until weaning, and male and female F1 rats were exposed for a further 104 weeks. Acrylamide concentration in drinking water was adjusted to provide a constant dose of 0.5, 1.5, and 3 mg/kg/day. Blood was collected from animals euthanized at 2, 60, 90, and 120 days and 53, 79, and 104 weeks after weaning. Low levels of AAVal and GAVal at postnatal day 24 suggested that little exposure to acrylamide occurred by placental or lactational transfer, and extensive metabolism to glycidamide occurred with a GAVal:AAVal ratio of 4. Adduct levels varied somewhat from 60 days to 2 years, with a GAVal:AAVal ratio of approximately 1. Adduct formation/day estimated at each timepoint at 3 mg/kg/day for AAVal was 1293 ± 220 and 1096 ± 338 fmol/mg/day for male and female rats, respectively. Adduct formation per day estimated at each timepoint at 3 mg/kg/day for GAVal was 827 ± 78 fmol/mg/day for male rats, and 982 ± 222 fmol/mg/day for female rats. The study has provided estimates of linearity for dose response, and variability in internal dose throughout an entire 2-year bioassay, including the early phases of pregnancy and lactation.

A novel interaction mode between acrylamide and its specific antibody

Since the discovery of high-level acrylamide (Acr) contamination in food, extensive international studies have focused on its toxicity and detection. By using a novel antigen synthetic strategy, we have successfully obtained a specific antibody towards acrylamide (Acr-Ab). Herein, the Acr-Ab and its interactions with Acr were characterized. Enzyme-linked immunosorbent assay (ELISA) and dynamic light scattering (DLS) investigations revealed that the conformational structure of Acr-Ab was sensitive to buffers. It showed a satisfied immunoreactivity in phosphate buffered saline (PBS), but denatured in water. In natural state, Acr-Ab had a trend of getting aggregation through their complementarity determining regions (CDRs). Adding Acr leaded to their disassembling. While mixed with Acr, Acr-Ab exhibits not only a fast, high-specific, and reversible non covalent binding (by surface plasmon resonance, SPR), but also a covalent alkylation with Acr through cysteine and histidine residues on its surface, as demonstrated by high-performance liquid chromatography (HPLC). Neither of the two reactions involves conformational change in secondary or tertiary structures as shown in circular dichroism spectra (CD). These special properties of Acr-Ab and the entirely new interaction mode with Acr will extend our knowledge of Acr related biosystem and facilitate the development of new detection strategies for Acr.

Validation of a food frequency questionnaire measurement of dietary acrylamide intake using hemoglobin adducts of acrylamide and glycidamide

OBJECTIVE

Acrylamide, a probable human carcinogen, is formed during high-heat cooking of many common foods. The validity of food frequency questionnaire (FFQ) measures of acrylamide intake has not been established. We assessed the validity of acrylamide intake calculated from an FFQ using a biomarker of acrylamide exposure.

METHODS

We calculated acrylamide intake from an FFQ in the Nurses' Health Study II. We measured hemoglobin adducts of acrylamide and its metabolite, glycidamide, in a random sample of 342 women. Correlation and regression analyses were used to assess the relationship between acrylamide intakes and adducts.

RESULTS

The correlation between acrylamide intake and the sum of acrylamide and glycidamide adducts was 0.31 (95% CI: 0.20-0.41), adjusted for laboratory batch, energy intake, and age. Further adjustment for BMI, alcohol intake, and correction for random within-person measurement error in adducts gave a correlation of 0.34 (CI: 0.23-0.45). The intraclass correlation coefficient for the sum of adducts was 0.77 in blood samples collected 1-3 years apart in a subset of 45 women. Intake of several foods significantly predicted adducts in multiple regression.

CONCLUSIONS

Acrylamide intake and hemoglobin adducts of acrylamide and glycidamide were moderately correlated. Within-person consistency in adducts was high over time.

Kinetics of elimination of urinary metabolites of acrylamide in humans

Acrylamide (AM), used in the manufacture of polyacrylamide and grouting agents, is produced during the cooking of foods. Workplace exposure to AM can occur through the dermal and inhalation routes. The objective of this study was to define the kinetics of elimination of AM and its metabolites following oral and dermal administration. This is the second part of a study in which metabolites and hemoglobin adducts of AM were determined in people (Fennell et al., 2005, Toxicol. Sci. 85, 447-459). (1,2,3-(13)C(3))AM was administered in an aqueous solution orally (single dose of 0.5, 1.0, or 3.0 mg/kg) or dermally (three daily doses of 3.0 mg/kg) to sterile male volunteers. Urine samples were collected at 0-2, 2-4, 4-8, 8-16, and 16-24 h following administration orally, or at 0-2, 2-4, 4-8, 8-16, and 16-24 h following each of three daily dermal doses. (13)C(3)-AM and its metabolites in urine, (13)C(3)-glycidamide, (13)C(3)-N-acetyl-S-(3-amino-3-oxopropyl)cysteine and its S-oxide, and (13)C(3)-N-acetyl-S-(3-amino-2-hydroxy-3-oxopropyl)cysteine, were quantitated using liquid chromatography-tandem mass spectrometry. The recovered urinary metabolites accounted for 45.6, 49.9, and 39.9% of a 0.5, 1.0, and 3.0 mg/kg oral dose (0-24 h), respectively, and for 4.5% of the dose after 3 mg/kg was administered daily for 3 days dermally (0-4 days). These results indicate that after oral administration AM is rapidly absorbed and eliminated. The half-life estimated for elimination of AM in urine was 3.1-3.5 h. After dermal administration, AM uptake is slow. This study indicated that skin provides a barrier that slows the absorption of AM, and results in limited systemic availability following dermal exposure to AM.

Automated method for measuring globin adducts of acrylamide and glycidamide at optimized Edman reaction conditions

The general population is exposed to acrylamide, a potential human carcinogen, through food and cigarette smoke. The assessment of human exposure to acrylamide is important in the evaluation of health risks associated with this chemical. Hemoglobin adducts of acrylamide (AA-Hb) and its primary metabolite glycidamide (GA-Hb) are established biomarkers of acrylamide exposure and methods to measure these biomarkers using modified Edman reaction are described. Only limited information about the optimal Edman reaction conditions such as pH or temperature is available for these adducts and the existing methods do not allow automation needed in biomonitoring studies. In this study, the yield of Edman products of AA-Hb and GA-Hb between pH 3-10 and at 35-55 degrees C at different time intervals, and the applicability of liquid-liquid extraction on diatomaceous earth for analyte extraction, were assessed and results were used in a new optimized method. The applicability of our optimized method was assessed by comparing results obtained with a convenience sample from 96 individuals with a conventional method. Maximum yield of Edman products was obtained between pH 6-7, heating the reaction solution at 55 degrees C for 2 h resulted in the same yields as with conventional conditions, and use of diatomaceous earth was found suitable for automated analyte extraction. Using these conditions, no difference was observed between our optimized and a conventional method. The median globin adduct values in the convenience sample are 129 pmol/g globin (range: 27-453 pmol/g globin) and 97 pmol/g globin (range: 27-240 pmol/g globin) for AA-Hb and GA-Hb, respectively. The GA-Hb/AA-Hb ratio decreases significantly with increasing AA-Hb values indicating that measurement of AA-Hb as well as GA-Hb are needed to appropriately assess human exposure to acrylamide.

Estimation of systemic toxicity of acrylamide by integration of in vitro toxicity data with kinetic simulations

Neurodegenerative properties of acrylamide were studied in vitro by exposure of differentiated SH-SY5Y human neuroblastoma cells for 72 h. The number of neurites per cell and the total cellular protein content were determined every 24 h throughout the exposure and the subsequent 96-h recovery period. Using kinetic data on the metabolism of acrylamide in rat, a biokinetic model was constructed in which the in vitro toxicity data were integrated. Using this model, we estimated the acute and subchronic toxicity of acrylamide for the rat in vivo. These estimations were compared to experimentally derived lowest observed effect doses (LOEDs) for daily intraperitoneal exposure (1, 10, 30, and 90 days) to acrylamide. The estimated LOEDs differed maximally twofold from the experimental LOEDs, and the nonlinear response to acrylamide exposure over time was simulated correctly. It is concluded that the integration of the present in vitro toxicity data with kinetic data gives adequate estimates of acute and subchronic neurotoxicity resulting from acrylamide exposure.