Lack of adverse health effects following 30-weeks of dietary exposure to acrylamide at low doses in male F344 rats

An integrated multi-omics analysis of the effects of the food processing-induced contaminant 2-monochloropropane-1,3-diol (2-MCPD) in rat heart

Many foods including edible oils contain 2-monochloropropane-1,3-diol (2-MCPD), a processing-induced chemical contaminant. Cardiotoxic effects have been shown to result from oral 2-MCPD exposure in rodents, but the underlying mechanisms of action remain poorly understood. We undertook a comprehensive multi-omics approach to assess changes at the transcriptomic, proteomic, and oxylipin levels in heart tissues from male F344 rats that were exposed to 0 or 40 mg/kg BW/day of 2-MCPD in the diet for 90 days, in a regulatory compliant rodent bioassay. Heart tissues were collected for RNA sequencing, quantitative PCR analysis, proteomic analysis via two-dimensional gel electrophoresis and mass spectrometry, and targeted lipidomic profiling by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Transcriptomic and proteomic data analyses revealed upregulation of immune/inflammatory response processes and downregulation of energy metabolism and cardiac structure and functions. Among differentially expressed gene-protein pairs, coronin-1A, a key leukocyte-regulating protein, emerged as markedly up-regulated. Oxylipin profiling highlighted a selective suppression of docosahexaenoic acid-derived metabolites, suggesting a disruption in cardioprotective lipid pathways. These findings suggest that 2-MCPD disrupts homeostasis through inflammatory activation and suppression of metabolic and cardiac function. This research provides insights into 2-MCPD's cardiotoxicity, emphasizing the need for further studies to support hazard characterization.

Leptadenia hastata Leaf Extract ameliorates oxidative stress and serum biochemical parameters in Streptozotocin-Induced diabetes in Wistar rats

Introduction

: Diabetes Mellitus is a major health problem characterized by hyperglycemia and disturbances in metabolism and implicated in causing oxidative stress. Treatment includes administration of oral hypoglycaemic agents with lifestyle modifications, these offer glycemic control, however, present limitations about availability, affordability and side effects. Traditional anti-diabetic plants are becoming popular in management of diabetes mellitus. This study was carried out to determine the efficacy of Leptadenaia hastata in treatment of diabetes.

Materials and methods

Diabetes mellitus was induced in using a single injection of streptozotocin (50 mg kg- 1 i.p.). The rats were divided into four groups of 5 rats each. Groups 3-6 received olive oil, 100 mg kg- 1 extract, 200 mg.kg- 1 extract and insulin (6IU kg- 1), respectively. 10 non-diabetic rats were grouped into two group receiving olive oil and 200 mg kg- 1 extract for 28 days. All groups were sacrificed by injecting with ketamine hydrochloride, blood was collected by cardiac puncture and centrifuged. The serum was analyzed for biochemical parameters. The liver was removed and homogenized with the supernatant of the resultant homogenate collected and used for analysis of oxidative stress enzymes.

Results

The extract significantly decreased serum AST (p < 0.05), ALP (p < 0.001), ALT (p < 0.05), TG (p < 0.01), TC (p < 0.001), creatinine (p < 0.001). It had no effect on SOD and CAT levels but it significantly increased (p < 0.001) GSH levels and reduced (p < 0.05) MDA level.

Conclusions

The n-hexane extract of Leptadenia hastata significantly decreased the levels of hepatic and renal serum biomarkers proving that it was beneficial in ameliorating diabetic related complications. The extract significantly increased GSH levels and reduced MDA level.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-022-01017-z.

Dietary Acrylamide Exposure and Risk of Site-Specific Cancer: A Systematic Review and Dose-Response Meta-Analysis of Epidemiological Studies

Diet is a main source of acrylamide exposure to humans. Existing observational data on the relationship between dietary exposure to acrylamide and risk of cancer are inconsistent. We performed a systematic review and dose-response meta-analysis of epidemiological studies evaluating the association between dietary acrylamide exposure and several site-specific cancer. A systematic literature search was conducted in PubMed, Scopus, and Web of Science databases until March 7, 2022. Studies were eligible if they were carried out in non-occupationally exposed adults, assessed dietary acrylamide exposure (μg/day) and reported risk estimates of cancer incidence (all but gynecological cancers). Using a random-effects model, we performed a meta-analysis of site-specific cancer risk comparing the highest vs. lowest category of dietary acrylamide exposure. We also carried out a one-stage dose-response meta-analysis assessing the shape of the association. Out of 1,994 papers screened, 31 were eligible (total of 16 studies), which included 1,151,189 participants in total, out of whom 48,175 developed cancer during the median follow-up period of 14.9 years (range 7.3-33.9). The mean estimated dose of dietary acrylamide across studies was 23 μg/day. Pooled analysis showed no association between the highest vs. lowest dietary acrylamide exposure and each site-specific cancer investigated, with no evidence of thresholds in the dose-response meta-analysis. There were also no associations between dietary acrylamide exposure and the risk of cancers when stratifying by smoking status, except for increased risk of lung cancer in smokers. In conclusion, high dietary acrylamide exposure was not associated with an increased risk of site-specific non-gynecological cancer.

Eruca sativa seed extract modulates oxidative stress and apoptosis and up-regulates the expression of Bcl-2 and Bax genes in acrylamide-induced testicular dysfunction in rats

Acrylamide (ACR) has been previously associated with male sexual dysfunction and infertility. Eruca sativa (L.) (arugula or rocket) have been widely used in traditional remedies in Mediterranean region and western Asia and was known for its strong aphrodisiac effect since Roman times. The current study was designed to investigate LC/MS analysis of total ethanol extract Eruca sativa (L.) and the efficiency and mechanism of action of Eruca sativa seed extract (ESS) in reducing hypogonadism induced by acrylamide in male rats. Male Wistar rats were divided into 6 groups (n = 7): control group, Eruca sativa seed extract (ESS) at doses of 100 and 200 mg\kg, acrylamide (ACR), ACR + ESS 100 mg/kg, and ACR + ESS 200 mg/kg. The animals received ACR at a dose of 10 mg/kg b.wt for 60 days. Sperm indices, testicular oxidative stress, testosterone hormone, and testicular histopathology and immunohistochemistry of PCNA and caspase-3 were investigated. Moreover, the expression level of testicular B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein (Bax) genes was evaluated. In respect to the LC/MS of total ethanol extract Eruca sativa (L.) seed revealed tentative identification of 39 compounds, which belongs to different classes as sulphur-containing compounds, flavonoids, phenolic acid, and fatty acids. Administration of ESS extract (100, 200 mg/kg) improved semen quality, diminished lipid peroxidation, enhanced testicular antioxidant enzyme, restored serum testosterone level, and reduced testicular degeneration and Leydig cell death in the rats intoxicated with ACR. However, the effects of ESS at the dose of 200 mg/kg were similar to that of control group. Furthermore, ESS treatment significantly induced anti-apoptotic effect indicated by elevation of both Bcl-2 and Bax expressions. Nutriceutics of ESS extract protects testis against ACR-induced testicular toxicity via normalizing testicular steroidogenesis, keeping Leydig cells, and improving oxidative stress status.

The Coffee-Acrylamide Apparent Paradox: An Example of Why the Health Impact of a Specific Compound in a Complex Mixture Should Not Be Evaluated in Isolation

The health implications of acrylamide in food are a matter of concern based on toxicological studies in rodents, which showed that doses of acrylamide more than 100 times higher than those estimated to result from dietary exposure in humans are carcinogenic; however, the cancer types reported in rodents are species-specific, and whether these results can be extrapolated to humans is still in question. In fact, human epidemiological studies revealed a general lack of association between dietary acrylamide exposure and the incidence of different cancer types. Even occupational exposure to acrylamide, resulting in acrylamide exposure nearly 10 times higher than dietary exposure, did not increase tumor occurrence. Furthermore, the consumption of coffee, which is a main contributor of dietary acrylamide exposure, actually decreases the overall incidence of cancer in humans and afford global health benefits, increasing both lifespan and healthspan on ageing. This paradox clearly illustrates the risk of evaluating an individual molecule independently of its complete food matrix, which may have other components that completely override the effects of the considered molecule.

Dietary acrylamide exposure in F344 rats and colon tumor-bearing nude nu/nu mice: Dataset of gene expression of cancer pathway targets and methylation status of tumor suppressor genes in colon mucosae and tumors

Dietary acrylamide, a thermally induced food contaminant, at a level (2 mg/kg diet) typifying higher occurrence in certain food products - is neither an independent carcinogen nor a tumor promoter in the colon. This is evidenced by our previous studies using the medium-term azoxymethane (AOM)-induced colon tumorigenesis assay in F344 rats and the human colon tumor xenograft model in athymic nude (nu/nu) mice (https://doi.org/10.1371/journal.pone.0073916) [1]. In addition, we found that acrylamide may act as a colon co-carcinogen in association with a known carcinogen (AOM) in F344 rats. Furthermore, exposure to acrylamide at 2 mg/kg in the diet was not associated with any toxicologically relevant changes in clinical biochemistry, hematology, and apical endpoints in healthy rats (exposed only to saline injections) (https://doi.org/10.1016/j.toxrep.2016.08.010) [2]. Here we report data from our previous investigation [1] on gene expression of cancer pathway targets as well as the methylation status of select tumor suppressor genes. Briefly, mRNA and DNA were extracted from (a) colon mucosae and tumors from F344 rats exposed to AOM or saline and (b) athymic nude (nu/nu) mice bearing human colon tumor xenografts, both exposed to dietary acrylamide at concentrations of 0 or 2 mg/kg diet for 20 and 4 weeks, respectively. RT² Profiler PCR Cancer PathwayFinder Arrays (Qiagen) and EpiTect Methyl II DNA Restriction kits and PCR Assays (Qiagen) were used to detect cancer-relevant gene expression (84 genes representing 9 pathways) and the methylation status of the CpG islands associated with 22 tumor suppressor genes in colon mucosae, tumors and xenografts. Additionally, RT² Profiler PCR Arrays (Qiagen) for cell cycle regulation, growth factors, inflammatory cytokines and receptors, and inflammatory response and autoimmunity were used to investigate the gene expression (84 genes in each array) of targets involved in these select cellular pathways in the colon mucosae from AOM-treated F344 rats.

Alterations of blood chemistry, hepatic and renal function, and blood cytometry in acrylamide-treated rats

Acrylamide is a vinyl monomer that is widely used for the synthesis of polyacrylamides, the treatment of drinking water, and as an additive in cosmetics. Acrylamide is also produced during the thermal processing of carbohydrate-rich foods. Although the potential toxic effects of acrylamide have been reported, few studies have evaluated biochemical parameters in blood. The present study investigated alterations of blood chemistry, hepatic function, and blood cytometry in acrylamide-treated rats. Thirty-two male Wistar rats were assigned to four experimental groups (n = 8/group): one control group received 0.3 ml of vehicle (saline solution), and the other three groups received acrylamide (25, 50, and 75 mg/kg, i.p., for 14 days). At the end of treatment, blood samples were collected to obtain serum, which was then processed using a Vitros250 device. For blood cytometry, the samples were processed in a Sysmex analyzer. The blood chemistry results showed that urea nitrogen, urea, and creatinine were elevated in the acrylamide-treated groups. Tests of hepatic function showed that total and direct bilirubins, transaminases, and alkaline phosphatase were also elevated compared with vehicle, whereas the levels of total proteins and albumin decreased. Blood cytometry showed that the levels of erythrocytes, hemoglobin, hematocrit, leukocytes, and platelets and mean cell volume decreased in the acrylamide-treated groups compared with vehicle. Overall, the present findings indicate that acrylamide causes deleterious effects on renal and hepatic physiology, producing dose-dependent alterations of blood chemistry and cytometry parameters in male Wistar rats.