Acrylamide induced immunosuppression in rats and its modulation by 6-MFA, an interferon inducer

Oral Administration of Acrylamide Worsens the Inflammatory Responses in the Airways of Asthmatic Mice Through Agitation of Oxidative Stress in the Lungs

Acrylamide is a toxic chemical substance produced when starch-rich foods are fried at high temperatures. Asthma is a chronic and complicated respiratory disease, of which genetic and environmental factors are the main triggers. Orally-received components may have an effect on asthma pathophysiology. The aim of this study was to investigate the role of AA as a stimulus in asthma. BALB/c mice were allocated into four groups as follows: two OVA-sensitized asthmatic groups, including one treated with AA by gavage feeding and one non-treated (asthma group), and two healthy (non-asthmatic) groups, one treated with AA by gavage feeding and one non-treated (negative control group). Airway hyperresponsiveness, cell count, cytokine levels in BAL fluid, lung histopathology, IgE levels, and oxidative stress indices including plasma level of MDA, pulmonary antioxidant enzymes (SOD and CAT) levels, HP content, and collagen fiber accumulation in lung tissue were measured. We found that the group of mice treated with both OVA and AA (asthmatic and AA-treated mice) experienced higher levels of asthma-associated biomarkers, including higher enhanced pause (Penh value), eosinophilic inflammation, mucus hyper secretion, goblet cell hyperplasia, total and OVA-specific IgE levels, IL-4, IL-5, and IL-13 levels than the group sensitized only with OVA (asthmatic mice). The OVA-AA-treated mice also experienced worsened levels of oxidative stress indicators. Healthy (non-asthmatic) mice that only received AA were in similar conditions to healthy untreated mice (negative control group). The OVA-AA-treated group showed more severe allergic asthma symptoms in comparison to the group only sensitized with OVA. Therefore, food/water contaminated with AA can act as a stimulant of allergic asthma and exacerbate the bronchial inflammatory responses.

Beyond detoxification: Pleiotropic functions of multiple glutathione S-transferase isoforms protect mice against a toxic electrophile

Environmental and endogenous electrophiles cause tissue damage through their high reactivity with endogenous nucleophiles such as DNA, proteins, and lipids. Protection against damage is mediated by glutathione (GSH) conjugation, which can occur spontaneously or be facilitated by the glutathione S-transferase (GST) enzymes. To determine the role of GST enzymes in protection against electrophiles as well as the role of specific GST families in mediating this protection, we exposed mutant mouse lines lacking the GSTP, GSTM, and/or GSTT enzyme families to the model electrophile acrylamide, a ubiquitous dietary contaminant known to cause adverse effects in humans. An analysis of urinary metabolites after acute acrylamide exposure identified the GSTM family as the primary mediator of GSH conjugation to acrylamide. However, surprisingly, mice lacking only this enzyme family did not show increased toxicity after an acute acrylamide exposure. Therefore, GSH conjugation is not the sole mechanism by which GSTs protect against the toxicity of this substrate. Given the prevalence of null GST polymorphisms in the human population (approximately 50% for GSTM1 and 20–50% for GSTT1), a substantial portion of the population may also have impaired acrylamide metabolism. However, our study also defines a role for GSTP and/or GSTT in protection against acrylamide mediated toxicity. Thus, while the canonical detoxification function of GSTs may be impaired in GSTM null individuals, disease risk secondary to acrylamide exposure may be mitigated through non-canonical pathways involving members of the GSTP and/or GSTT families.

Effects of long term oral acrylamide administration on alpha naphthyl acetate esterase and acid phosphatase activities in the peripheral blood lymphocytes of rats

Acrylamide is an important industrial chemical; it also is formed in starch-rich foodstuffs during baking, frying and roasting. Most acrylamide exposure occurs by ingestion of processed foods. We investigated possible immunotoxic effects of extended administration of low doses of acrylamide in rats. To do this, we measured alpha-naphthyl acetate esterase (ANAE) and acid phosphatase (ACP-ase) activities in peripheral blood lymphocytes. Male and female weanling Wistar rats were administered 2 or 5 mg acrylamide/kg/day in drinking water for 90 days. Peripheral blood was sampled at the end of the administration period. We found ANAE staining in eosinophils and T-lymphocytes, but not in monocytes, platelets, B-lymphocytes and neutrophils. ACP-ase was found in B-lymphocytes. We found a significant reduction of the ratio of ANAE:ACP-ase in lymphocytes of the experimental animals compared to controls. We found no statistically significant differences between the doses or sexes. We found that acrylamide ingested in processed foods might affect the immune system adversely by decreasing the population of mature T- and B-lymphocytes.

Dietary Acrylamide and the Risks of Developing Cancer: Facts to Ponder

Acrylamide (AA) is a water soluble white crystalline solid commonly used in industries. It was listed as an industrial chemical with potential carcinogenic properties. However to date, AA was used to produce polyacrylamide polymer, which was widely used as a coagulant in water treatment; additives during papermaking; grouting material for dams, tunnels, and other underground building constructions. AA in food could be formed during high-temperature cooking via several mechanisms, i.e., formation via acrylic acid which may be derived from the degradation of lipid, carbohydrates, or free amino acids; formation via the dehydration/decarboxylation of organic acids (malic acid, lactic acid, and citric acid); and direct formation from amino acids. The big debate is whether this compound is toxic to human beings or not. In the present review, we discuss the formation of AA in food products, its consumption, and possible link to the development of any cancers. We discuss the body enzymatic influence on AA and mechanism of action of AA on hormone, calcium signaling pathways, and cytoskeletal filaments. We also highlight the deleterious effects of AA on nervous system, reproductive system, immune system, and the liver. The present and future mitigation strategies are also discussed. The present review on AA may be beneficial for researchers, food industry, and also medical personnel.

Acrylamide attenuated immune tissues’ function via induction of apoptosis and oxidative stress: Protection by l-carnitine

Acrylamide (ACR), with high prevalence in starchy food, has been associated with the development of several organ toxicities such as immunotoxicity. This study aimed to demonstrate the role of oxidative stress and apoptosis as the mechanisms involved in ACR-induced immunotoxicity in mice. Mice were randomly assigned to six groups and treated as follows: control (normal saline), cyclophosphamide (200 mg kg–1), ACR groups (12.5, 25 and 50mg kg–1, orally), and l-carnitine (l-CAR; 100 mg kg–1) + ACR (50 mg kg–1). After 30 days of exposure, mice were killed and immunotoxic response was evaluated via immune blood cells count and body/organ weights. Oxidative stress parameters and pathological examination were done in thymus and spleen. Also, the apoptosis was evaluated via flow cytometric by annexin V/FITC kit in the splenocytes. Our results indicated that ACR could induce immunotoxicity characterized by reduction in immune blood cells, body/organ weights, and pathological changes in spleen. The assessment of oxidative stress markers revealed increase in lipid peroxidation, protein carbonyl content, and depletion of glutathione level. Also, increased apoptosis was observed in splenocytes after ACR administration compared to the control group. These alterations were markedly normalized by coadministration of l-CAR (as a potent antioxidant). Taken together, the results of this study showed the potential of ACR to induce immunotoxicity through provoking oxidative stress and inducing apoptosis and the protective effect of l-CAR to attenuate this toxicity. These findings will help in elucidating the toxicity mechanism induced by ACR.

Relationships between acrylamide and glycidamide hemoglobin adduct levels and allergy-related outcomes in general US population, NHANES 2005-2006

BACKGROUND

Acrylamide-induced immunotoxicity and allergic dermatitis have been reported in animal experiments and clinical reports, respectively. However, epidemiological evidence from the general population is limited.

OBJECTIVES

The purpose of the present study was to estimate the associations between acrylamide exposure and allergy-related outcomes in the general US population.

METHODS

A total of 6982 subjects were selected from the National Health and Nutrition Examination Survey 2005-2006 (NHANES). Internal exposure was measured by the hemoglobin adducts of acrylamide (HbAA) and its metabolite glycidamide (HbGA). Allergy-related outcomes including asthma, hay fever, allergy, itchy rash, sneeze, wheeze and eczema were obtained by self-administered questionnaires. Allergic sensitization was assessed by the total immunoglobulin E (IgE) levels. The associations of HbAA and HbGA quartiles with allergy-related outcomes were calculated using logistic regression models with multivariable adjustments. Analyses were additionally stratified according to age, gender and serum cotinine levels.

RESULTS

When setting quartile 1 of HbAA as reference, the odds ratios (ORs) [95% confidence intervals (CIs)] of quartile 2 to 4 for eczema were 1.18 (0.79-1.76), 1.14 (0.73-1.78) and 1.58 (1.14-2.18), respectively (p_trend = 0.002). Individuals at the highest quartile of HbGA had significantly elevated likelihoods of itchy rash (OR = 1.37, 95% CI = 1.02-1.83, p_trend = 0.032) and eczema (OR = 1.45, 95% CI = 1.06-1.97, p_trend = 0.044). The stratification analyses indicated various results in different subgroups.

CONCLUSIONS

This study indicated significant associations between HbAA and HbGA levels and the likelihoods of allergy-related outcomes in the general US population, depending on age, gender and smoke exposure status. These findings suggested potential public health concerns for the widespread exposure to acrylamide.

Toxicological effects of short-term dietary acrylamide exposure in male F344 rats

We recently reported that acrylamide, a known rodent and probable human carcinogen, does not increase the risk of azoxymethane (AOM)-induced rat colon precancerous lesions when administered through the diet. Here, we present toxicological data from non-AOM-injected rats. Briefly, male F344 rats were randomized into four dietary groups and received experimental diets based on AIN-93G formulation and containing acrylamide at 0 (control), 5, 10 or 50mg/kg diet (wt/wt) ad libitum for 10 weeks, after which they were killed and their blood collected for hematological and biochemical markers. Acrylamide at the higher doses (10 and 50mg/kg diet) significantly lowered (p<0.05) serum total high density lipoprotein and total testosterone and increased serum lipase in comparison to the control. Blood hematocrit values and lymphocyte counts were significantly lower (p<0.05) in the high dose acrylamide (50mg/kg diet) group compared to control, with a concomitant decrease in hemoglobin level, mean corpuscular volume and mean corpuscular hemoglobin. These results provide additional hazard characterization data and strengthen the notion that at high doses, acrylamide may involve systemic toxicity potentiating tumorigenesis in experimental animals. Further studies are required to understand the health effects of food-borne acrylamide, especially at the lower exposures typified by human diets.

Prenatal exposure to polychlorinated biphenyls and dioxins is associated with increased risk of wheeze and infections in infants

The birth cohort BraMat (n = 205; a sub-cohort of the Norwegian Mother and Child Cohort Study (MoBa) conducted by the Norwegian Institute of Public Health) was established to study whether prenatal exposure to toxicants from the maternal diet affects immunological health outcomes in children. We here report on the environmental pollutants polychlorinated biphenyls (PCBs) and dioxins, as well as acrylamide generated in food during heat treatment. The frequency of common infections, eczema or itchiness, and periods of more than 10 days of dry cough, chest tightness or wheeze (called wheeze) in the children during the first year of life was assessed by questionnaire data (n = 195). Prenatal dietary exposure to the toxicants was estimated using a validated food frequency questionnaire from MoBa. Prenatal exposure to PCBs and dioxins was found to be associated with increased risk of wheeze and exanthema subitum, and also with increased frequency of upper respiratory tract infections. We found no associations between prenatal exposure to acrylamide and the health outcomes investigated. Our results suggest that prenatal dietary exposure to dioxins and PCBs may increase the risk of wheeze and infectious diseases during the first year of life.

The delayed type hypersensitivity assay using protein and xenogeneic cell antigens

The delayed-type hypersensitivity (DTH) assay has a lengthy history in immunotoxicity testing since it was one of the original functional assays included in the National Toxicology Program (NTP) immunotoxicology test panel. Based on NTP data analysis, the DTH assay is among the most predictive immunotoxicity tests when included with at least two other immune parameters. The DTH assay has the advantage of being: (1) a useful measure of cell-mediated immunity, (2) an in vivo assay where there is less opportunity for ex vivo confounders and (3) a clinically significant human correlate to the tuberculin test. Disadvantages of the DTH assay are that it is potentially labor-intensive to perform, it is somewhat resistant to automation and, when compared with the cyctotoxic T lymphocyte (CTL) assay, it is a relatively crude measurement. However, some groups have been attempting to address the limitations of the DTH assays (see Note 1).The assay is related to the contact hypersensitivity response (CHR), which is covered in another chapter. The DTH response has been used as an indicator of cell-mediated immune status and is dependent upon both T helper 1(Th1)-driven responses as well as cell recruitment and chemotaxis to a local site. As a result, the DTH functional response may be influenced by disruption of either Th1-driven, antigen-dependent T cell development or mobilization of sensitized T cells to a local site. The present chapter describes four common protocols with consideration restricted to protein and xenogeneic cell immunogens.