Carcinogenic heterocyclic amines in model systems and cooked foods: a review on formation, occurrence and intake

Association between fish and shellfish consumption, n-3 polyunsaturated fatty acids, and gastric cancer risk: the Japan Public Health Center-based Prospective Study

PURPOSE

Fish and shellfish consumption is suggested to be a cancer-protective factor. However, studies investigating this association for gastric cancer, especially considering Helicobacter pylori (H. pylori) and atrophic gastritis (AG), are limited. We investigated gastric cancer risk associated with fish, shellfish, and n-3 polyunsaturated fatty acids (n-3 PUFAs) consumption among Japanese adults.

METHODS

90,504 subjects enrolled in the Japan Public Health Center-based Prospective Study (JPHC Study) were followed until December 2013. Dietary intake data were collected using a food frequency questionnaire. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for gastric cancer risk associated with fish and shellfish consumption and marine n-3 PUFAs (sum of eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA)) using Cox proportional hazards models. Among those with avaliable data, we conducted a subgroup analysis taking H. pylori infection and AG status  into consideration.

RESULTS

There were 2,701 gastric cancer cases during an average of 15 years of follow-up. We observed an increased gastric cancer risk for salted fish consumption for men [HR for fifth quintile versus first quintile 1.43 (95% CI 1.18-1.75)] and for women [HR 1.33 (95% CI 1.00-1.77)]. We observed a weak risk reduction trend for women as the intake of marine n-3 PUFAs increased (p-trend:0.07). When we included H. pylori infection and atrophic gastritis status in the analysis, the associations diminished.

CONCLUSION

Our results suggest that salted fish increases gastric cancer risk for men and women, while marine n-3 PUFAs marginally decreases this risk among women in Japan.

Heterocyclic Amines Disrupt Lipid Homeostasis in Cryopreserved Human Hepatocytes

Metabolic dysfunction associated-steatotic liver disease (MASLD)/metabolic dysfunction-associated steatohepatitis (MASH) is the liver manifestation of metabolic syndrome, which is characterized by insulin resistance, hyperglycemia, hypertension, dyslipidemia, and/or obesity. Environmental pollutant exposure has been recently identified as a risk factor for developing MASH. Heterocyclic amines (HCAs) are mutagens generated when cooking meat at high temperatures or until well-done. Recent epidemiological studies reported that dietary HCA exposure may be linked to insulin resistance and type II diabetes, and we recently reported that HCAs induce insulin resistance and glucose production in human hepatocytes. However, no previous studies have examined the effects of HCAs on hepatic lipid homeostasis. In the present study, we assessed the effects of two common HCAs, MeIQx (2-amino-3, 8-dimethylimidazo [4, 5-f] quinoxaline) and PhIP (2-amino-1-methyl-6-phenylimidazo[4, 5-b] pyridine), on lipid homeostasis in cryopreserved human hepatocytes. Exposure to a single concentration of 25 μM MeIQx or PhIP in human hepatocytes led to dysregulation of lipid homeostasis, typified by significant increases in lipid droplets and triglycerides. PhIP significantly increased expression of lipid droplet-associated genes, PNPLA3 and HSD17B13, and both HCAs significantly increased PLIN2. Exposure to MeIQx or PhIP also significantly increased expression of several key genes involved in lipid synthesis, transport and metabolism, including FASN, DGAT2, CPT1A, SCD, and CD36. Furthermore, both MeIQx and PhIP significantly increased intracellular cholesterol and decreased expression of PON1 which is involved in cholesterol efflux. Taken together, these results suggest that HCAs dysregulate lipid production, metabolism, and storage. The current study demonstrates, for the first time, that HCA exposure may lead to fat accumulation in hepatocytes, which may contribute to hepatic insulin resistance and MASH.

Effect of air-frying on formation and correlations of polycyclic aromatic hydrocarbons, acrylamide, and heterocyclic aromatic amines in foods and risk assessment

The levels of acrylamide (AA), four polycyclic aromatic hydrocarbons (PAH4), and heterocyclic aromatic amines (HAAs) in 184 air-fried agricultural, fishery, and animal products were measured using GC-MS and UPLC-MS/MS. Among the tested samples, sea algae exhibited the highest levels of PAH4 and eight specific HAAs (HAA8), while root and tuber crops had the greatest amount of AA. Agricultural and fisheries products had higher levels of all three contaminants, while livestock products had an inverse correlation between PAH4 and HAA8. The margin of exposure in the Korean population is considered "unlikely a concern" for all samples for PAH4 and HAA8, however, that for AA in cereal, vegetable, and root and tuber crops is deemed "may be a concern", with a value < 10,000 in all age groups. These findings suggest a need to evaluate dietary AA exposure in certain food categories and further research to minimize AA formation during air frying.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-024-01639-4.

Hemoglobin and free iron influence the aroma of cooked beef by influencing the formation and release of volatiles

Cooked beef flavour is influenced by formation and release of odour-active volatiles. We hypothesised the aroma of cooked beef is affected by the concentration of heme proteins and free iron. To test our hypothesis, we spiked ground beef semitendinosus with different concentrations of hemoglobin or free iron. The patties were then grilled, and their volatile profiles were measured using gas chromatography - mass spectrometry and their sensory attributes were measured by a trained sensory panel. We found that spiking hemoglobin at 2 mg/g could suppress the release of linear aldehydes while increasing the formation of some Maillard-derived volatiles, which could potentially reduce the livery odour. The addition of free iron at 13.48 µg/g increased the livery and oxidised fat odour of cooked beef by increasing the formation of typical lipid-derived volatiles, such as 1-octen-3-ol, hexanal, and several akylfurans.

Targeting beta-catenin signaling for prevention of colorectal cancer - Nutraceutical, drug, and dietary options

Progressive up-regulation of β-catenin signaling is very common in the transformation of colorectal epithelium to colorectal cancer (CRC). Practical measures for opposing such signaling hence have potential for preventing or slowing such transformation. cAMP/PKA activity in colon epithelium, as stimulated by COX-2-generated prostaglandins and β2-adrenergic signaling, boosts β-catenin activity, whereas cGMP/PKG signaling has the opposite effect. Bacterial generation of short-chain fatty acids (as supported by unrefined high-carbohydrate diets, berberine, and probiotics), dietary calcium, daily aspirin, antioxidants opposing cox-2 induction, and nicotine avoidance, can suppress cAMP production in colonic epithelium, whereas cGMP can be boosted via linaclotides, PDE5 inhibitors such as sildenafil or icariin, and likely high-dose biotin. Selective activation of estrogen receptor-β by soy isoflavones, support of adequate vitamin D receptor activity with UV exposure or supplemental vitamin D, and inhibition of CK2 activity with flavanols such as quercetin, can also oppose β-catenin signaling in colorectal epithelium. Secondary bile acids, the colonic production of which can be diminished by low-fat diets and berberine, can up-regulate β-catenin activity by down-regulating farnesoid X receptor expression. Stimulation of PI3K/Akt via insulin, IGF-I, TLR4, and EGFR receptors boosts β-catenin levels via inhibition of glycogen synthase-3β; plant-based diets can down-regulate insulin and IGF-I levels, exercise training and leanness can keep insulin low, anthocyanins and their key metabolite ferulic acid have potential for opposing TLR4 signaling, and silibinin is a direct antagonist for EGFR. Partially hydrolyzed phytate can oppose growth factor-mediated down-regulation of β-catenin by inhibiting Akt activation. Multifactorial strategies for safely opposing β-catenin signaling can be complemented with measures that diminish colonic mutagenesis and DNA hypomethylation - such as avoidance of heme-rich meat and charred or processed meats, consumption of phase II-inductive foods and nutraceuticals (e.g., Crucifera), and assurance of adequate folate status.

Association of meat consumption with the risk of gastrointestinal cancers: a systematic review and meta-analysis

BACKGROUND

The association between gastrointestinal cancer and types of meat consumption, including red meat, processed meat, or a combination of both, remains disputable. Therefore, we performed a systematic review and meta-analysis of prospective cohort studies to estimate the association between meat consumption and gastrointestinal cancer risk.

METHODS

PubMed, EmBase, and the Cochrane library databases were searched systematically for eligible studies that investigated the relation between meat consumption and the risk of developing gastrointestinal cancers, including esophageal cancer (EC), gastric cancer (GC), colorectal cancer (CRC), colon cancer (CC), rectal cancer (RC), pancreatic cancer (PC), and hepatocellular carcinoma (HCC) throughout February, 2023. The pooled relative risk (RR) with 95% confidence interval (CI) was assigned as an effect estimate and calculated using a random-effects model with inverse variance weighting.

RESULTS

Forty cohorts comprising 3,780,590 individuals were selected for the final quantitative analysis. The summary results indicated that a higher red meat consumption was associated with an increased risk of CRC (RR: 1.09; 95% CI: 1.02-1.16; P = 0.007) and CC (RR: 1.13; 95% CI: 1.03-1.25; P = 0.011). Moreover, a higher processed meat consumption was associated with an increased risk of CRC (RR: 1.19; 95% CI: 1.13-1.26; P < 0.001), CC (RR: 1.24; 95% CI: 1.13-1.26; P < 0.001), and RC (RR: 1.24; 95% CI: 1.08-1.42; P = 0.002). Furthermore, a higher total consumption of red and processed meat was associated with an increased risk of CRC (RR: 1.13; 95% CI: 1.06-1.20; P < 0.001), CC (RR: 1.17; 95% CI: 1.04-1.33; P = 0.012), and RC (RR: 1.20; 95% CI: 1.04-1.39; P = 0.016). Finally, the strength of higher consumption of total red and processed meat with the risk of GC, and higher consumption of red meat with the risk of RC in subgroup of high adjusted level was lower than subgroup of moderate adjusted level, while the strength of higher consumption of processed meat with the risk of RC and HCC in subgroup of follow-up ≥ 10.0 years was higher than subgroup of follow-up < 10.0 years.

CONCLUSIONS

This study found that meat consumption was associated with an increased risk of CRC, CC, and RC, and dietary intervention could be considered an effective strategy in preventing CRC.

Meat and dairy products intake is associated with gastric cancer: Case-control study findings

Countries experiencing a significant shift toward Western lifestyle are facing an increased risk of gastric cancer (GC). While many studies have explored the link between diet and GC, the role of meat and dairy consumption remains uncertain. To delve deeper into this association, we conducted a case-control study in Jordan involving 173 GC cases and 314 controls, matched by age and marital status. Using a validated food frequency questionnaire, we assessed the intake of different dairy and meat products. The adjusted odds ratios and corresponding 95% confidence intervals indicated a strong correlation between high intake of red meat, milk, and buttermilk and GC. Our multinomial logistic regression analysis revealed that daily consumption of red meat (≥1 serving/day; OR, 3.34 [95% CI 1.85-6.03, p value of trend <.001], ≥1 serving/day) and weekly intake of milk (2-3 servings/week; OR, 2.04 [95% CI 1.14-3.64, p value of trend = .041]) and buttermilk (2-3 servings/week; OR, 2.07 [95% CI 1.12-3.83, p value of trend = .018], per 2-3 servings/week) were significantly associated with an increased risk of GC. Furthermore, consuming cooked eggs daily (OR = 2.44, 95% CI 1.24-4.79, p trend <.001) or weekly (OR, 3.34, 95% CI 1.58-7.10, p value of trend <.001) was also associated with an increased risk of GC. These findings highlight the potential health risks associated with excessive meat and some dairy products consumption and suggest that a balanced intake of these products, along with eggs, may help prevent GC.

Challenges and Suggestions in the Management of Stomach and Colorectal Cancer in Uzbekistan: The Third Report of the Uzbekistan-Korea Oncology Consortium

In general, as the national standard of living and life expectancy of people increase, the health burden of cancer also increases. Prevention strategies, including the screening and investigation of the causes of cancer as well as the expansion of treatment infrastructure, are necessary. In this review, we discussed the management strategies for gastric and colorectal cancers in Uzbekistan. Gastrointestinal cancers can be significantly prevented by certain screening strategies such as endoscopic examination. Furthermore, as both cancer types are closely related to the eating habits and lifestyles of people in Uzbekistan, such causes should be investigated and prevented. Practical advice to increase the efficiency of treatment is included, considering the current situation in Uzbekistan. Data from South Korea, which has performed nationwide screening for two decades and has made progress in improving the prognosis of patients with gastrointestinal cancers, will be discussed as a literature control.

Simultaneous determination of heterocyclic aromatic amines and N-nitrosamines in fried bacon cubes and slices using LC-(ESI/APCI)-MS/MS

Bacon manufacturing involves several processing steps including nitrite curing, followed by cooking processes, typically frying. During these processes, harmful processing contaminants such as N-nitrosamines (NAs) and heterocyclic aromatic amines (HAAs) can be formed. Consequently, we developed and validated a multi-class method for quantification of the most frequently reported HAAs and NAs in fried bacon. Satisfactory repeatability and reproducibility with limits of quantification between 0.1 and 0.5 ng g^-1 for most of the compounds were achieved. Quantification in pan-fried bacon cubes and slices revealed generally low levels of individual HAAs (≤1.5 ng g^-1), except in ready-to-eat bacon (0.9-2.9 ng g^-1). Differences in amounts of individual HAAs were observed in cubes and slices, most likely due to meat thickness. Among volatile NAs (VNAs), only N-nitrosopiperidine (NPIP), N-nitrosopyrolidine (NPYR), and N-nitrosodibutylamine (NDBA) were found at generally low concentrations (≤5 ng g^-1). In contrast, non-volatile NAs (NVNAs) were present in all tested samples at considerably higher amounts, for example, N-nitroso-thiazolidine-4-carboxylic acid (NTCA) at 12-77 ng g^-1. N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosodipropylamine (NDPA) were not detected in any samples. Statistical evaluation and principal component analysis revealed some differences among tested samples. Dietary exposure estimation of the Danish population to HAAs and NAs showed the highest exposure in the teenage group (10-17 years).

Advantageous Effects of Sumac Usage in Meatball Preparation on Various Quality Criteria and Formation of Heterocyclic Aromatic Amines

Heterocyclic aromatic amines (HAAs) are mutagenic/carcinogenic compounds that can be formed during the cooking process of proteinaceous foods such as meat. Therefore, it is needed to inhibit or reduce their formations in cooked meats. Hereby, the effects of sumac usage (0.5%, w/w) in beef meatball preparation on the formation of HAAs and some quality parameters (water, pH, cooking loss, and lipid oxidation values) of meatballs cooked at 150 and 250 °C were investigated. The sumac usage caused a reduction in pH (p < 0.01), cooking loss (p < 0.05), lipid oxidation level (TBARS, p < 0.01), and total HAA amount (p < 0.05) of the samples. In addition, increasing the cooking temperature significantly decreased the pH value (p < 0.01) and increased the cooking loss (p < 0.05) of the samples. Only one compound, 2-amino-3,8-dimethylimidazo [4,5-ƒ]quinoxaline (MeIQx), from nine different HAAs studied in this study, could be determined, and the levels of the other HAAs studied were lower than their detection limits. On the other hand, MeIQx was not detected in the samples cooked at 150 °C, it was only determined in the control group samples cooked at 250 °C. The sumac usage completely inhibited MeIQx formation in the samples. Due to its positive effect on cooking loss value, lipid oxidation level, and MeIQx formation, it can be suggested to use sumac powder in meatball preparation.

Meat Intake and the Risk of Bladder Cancer: A Systematic Review and Meta-Analysis of Observational Studies

The evidence for the association between meat intake and the risk of bladder cancer (BC) is still inconclusive. A total of 29 studies involving 1,475,125 participants and 18,836 cases of BC were included in the meta-analysis. Among these studies, 11 reported total meat intake, 20 reported red meat intake, 19 reported processed meat intake, 15 reported white meat intake, and 15 reported fish intake. The results suggested that there was an overall increase in BC risk associated with total meat intake (RR = 1.10; 95% confidence interval: 0.92-1.31; I² = 55.20%; P = 0.014), and a higher red meat (RR = 1.23; 95% CI: 1.08-1.39; I² = 51.30%; P = 0.004) or processed meat (RR = 1.16; 95% CI: 1.08-1.25; I² = 28.00%; P = 0.125) intake may increase the risk of BC. In contrast, a higher intake of fish (RR = 0.80; 95% CI: 0.67-0.95; I² = 62.90%; P = 0.001) was inversely associated with the risk of BC. Moreover, we did not observe an association between white meat (RR = 0.96; 95% CI: 0.83-1.10; I² = 53.70%; P = 0.007) and the risk of BC. Our findings suggested that dietary intervention may be an effective approach to preventing BC, which still needs to be confirmed by further well-designed observational studies.

The Effects of the Marination Process with Different Vinegar Varieties on Various Quality Criteria and Heterocyclic Aromatic Amine Formation in Beef Steak

Herein, the effect of the dipping (static) marination process (at 4 °C for 2 h) with different types of vinegar (balsamic, pomegranate, apple, and grape) on various quality properties, including texture and protein profile of beef steaks and the formation of heterocyclic aromatic amines (HAAs) in beef steaks cooked on a hot plate (at 200 °C for 24 min), were determined. The results showed that 3.12-4.13% of the marinate liquids were absorbed by beef steak as a result of the marination process. No significant differences (p > 0.05) were observed between the marinated and cooked beef steaks in terms of water content, cooking loss, thiobarbituric acid reactive substances (TBARS) value, hardness, cohesiveness, and chewiness. However, significant differences were detected in terms of pH value and color values (L*, a*, and b*) (p < 0.01), and springiness, 2-amino-3,8-dimethylimidazo (4,5-f) quinoxaline (MeIQx) and total HAA content (p < 0.05). The marination with pomegranate vinegar resulted in the formation of darker steak, while a lighter one was obtained when apple vinegar was used in the marination. The use of balsamic and grape vinegar in the marination process decreased the springiness value compared to the control group. The myofibrillar proteins of beef steaks marinated with different types of vinegar generally showed a similar sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) profile. However, some differences were observed in the band density of some proteins depending on the trial and the type of marination. In this study, of the nine examined HAAs, only two (2-amino-3-methylimidazo (4,5-f) quinoline (IQ) and MeIQx) could be detected and quantified. IQ was detected only in the control group steak (up to 0.51 ng/g), while MeIQx was detected in all treatment groups (up to 2.22 ng/g). The total HAA content varied between 0.59-2.22 ng/g. It was determined that the marination process with different vinegar types had different effects on the total HAA content of the steaks. Using balsamic and apple vinegar in the marination process decreased the total HAA content compared to the control group, but this decrease was not statistically significant (p > 0.05). On the other hand, using grape and pomegranate vinegar in the marination process increased the total HAA content, but this increase was only significant (p < 0.05) in the marination with pomegranate vinegar.

Association of dietary patterns and food groups intake with multimorbidity: A prospective cohort study

BACKGROUND

Although diet has been extensively studied in relation to individual chronic conditions, studies linking diet with multiple chronic conditions (multimorbidity) remained scarce. We aimed to undertake a comprehensive analysis evaluating associations of overall dietary patterns and specific food groups with long-term risk of multimorbidity.

METHODS

The study included 348,290 participants from UK Biobank who completed eligible food frequency questionnaires (FFQ) and were not diagnosed with any of the 38 chronic or mental health conditions of interest at baseline (2006-2010). Dietary patterns were identified using exploratory factor analysis. Cox regression models were used to estimate corresponding hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

The median follow-up was 8.01 years, and 50,837 (14.60%) participants developed multimorbidity. Among the three identified dietary patterns, the Western Pattern was associated with an increased risk of multimorbidity (HR_{Q5 vs Q1} = 1.06, 95% CI: 1.03-1.09), while inverse associations were observed for moderate adherence to the White Meat Pattern (HR_{Q3vs Q1} = 0.97, 95% CI: 0.94-0.99) and highest adherence to the Prudent Pattern (HR_{Q5 vs Q1} = 0.92, 95% CI: 0.90-0.95). For specific food groups, more frequent intakes of processed meat and poultry were associated with higher risks of multimorbidity, whereas higher intake frequency of fish and more intakes of fruits and cereal were associated with decreased risks.

CONCLUSION

Dietary patterns and specific food groups are associated with the risk of multimorbidity. These findings suggest the importance of considering dietary interventions in the prevention and management of multimorbidity.

Effect of Different Roasting Conditions and Coreopsis Extract on Heterocyclic Amine Formation in Roast Lamb Products

ABSTRACT

Heterocyclic amines (HCAs), which are known carcinogens in thermally processed foods, were investigated in roast lamb patties under various time and temperature conditions. HCAs in lamb products roasted at some temperatures increased with roasting time. An exponential model with a time factor fit well for the production of HCAs. The mean pH and cooking loss at various temperatures were also determined. The mean pH decreased as the temperature increased. Coreopsis extract was added to lamb patties roasted at 230°C for 15 min per side. The amount of coreopsis extract added had a significant effect on HCA development. A weak positive relationship was observed between the antioxidant activity of the lamb patty with the coreopsis extract and the inhibitory effect of coreopsis extract on various HCAs, with a correlation coefficient of 0.14 to 0.44 (P > 0.05). Coreopsis extract containing flavonoids can be a beneficial additive for production of barbecue meat.

HIGHLIGHTS

Molecular pathogenesis and emerging targets of gastric adenocarcinoma

Gastric adenocarcinoma (GC) is a devastating disease and is the third leading cause of cancer deaths worldwide. This heterogeneous disease has several different classification systems that consider histological appearance and genomic alterations. Understanding the etiology of GC, including infection, hereditary conditions, and environmental factors, is of particular importance and is discussed in this review. To improve survival in GC, we also must improve our therapeutic strategies. Here, we discuss new targets that warrant further exploration.

Effects of Chlorophyll a and b in Reducing Genotoxicity of 2-Amino-3,8-dimethylimidazo[4,5-F]quinoxaline (MeIQx)

In this study, the protective effects of chlorophyll a and chlorophyll b (0.5 and 1 µM) against the heterocyclic amine compound 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx, 4.69 µM, 9.38 µM, 23.45 µM) with somatic mutation and recombination test in Drosophila melanogaster are investigated. Chronic applications are performed to transheterozygous larvae with respect to two recessive genes, mwh (multiple wing hair) and flr3 (flare), by using Drosophila strains. The genotoxic effects of MeIQx are primarily determined for third instars larvae. In antigenotoxicity studies, two different application groups are constituted. While for the first group doses of chlorophyll a, b, and MeIQx are given to the third instars larvae simultaneously, for the second group doses of MeIQx are applied at the third instars after doses of chlorophyll a and b are given to at the second instars larvae. Chlorophyll a and b are effective in reducing genotoxic effects of MeIQx by both applications on individuals and it is observed that the pretreatment method is much more effective than the simultaneous one. There are similar results for chlorophyll a and b in efficacy.

Assessment of dietary exposure to heterocyclic amines based on the Korean total diet study

Heterocyclic amines (HCAs) are contaminants in proteinaceous foods produced by cooking at high temperatures. This study was the first assessment of exposure to HCAs using the Korean total diet study. Twelve HCAs were analysed in 1,232 pooled samples using six isotope-labelled internal standards and HPLC-MS/MS. The daily intake of HCAs in the Korean population was estimated based on the concentration of HCAs in the total diet study samples and individual food consumption data from the Korean National Health and Nutrition Examination Survey. Among HCAs, the intake of β-carbolines, such as harman and norharman, was the highest, followed by the intake of PhIP. The primary sources of HCA intake were meat, fish, shellfish, and beverages, including alcohol. The margin of exposure to PhIP was 2,349,000 at the average level and 373,000 at the 95^th percentile in the Korean population. The estimated daily intake of all HCAs in the Korean population was considered safe.

Chlorogenic acid and Epicatechin: An efficient inhibitor of heterocyclic amines in charcoal roasted lamb meats

There are few studies on controlling the formation of heterocyclic amines (HAs) by adding polyphenols to roasted lamb. The aim of this study was to assess the inhibitory effect of 0.025, 0.125, and 0.625 mmol of chlorogenic acid, epicatechin, rutin, quercetin and quinic acid on the formation of HAs in charcoal roasted lamb, respectively, by UHPLC-MS/MS. The results indicated that Harman, Norharman, PhIP, IQx and 8-MeIQx were detected, but both chlorogenic acid and epicatechin greatly inhibited the formation of IQx, 8-MeIQx, Norharman, Harman and PhIP, and epicatechin had better inhibitory effect than chlorogenic acid. PLSR-VID analysis suggested the key precursors of HAs formation in roasted lamb were glucose, ribose, fructose, isoleucine, valine, and lysine. In addition, this work also implied that the potential mechanism of inhibition of HAs formation by chlorogenic acid and epicatechin in roasted lamb might attribute to competitive chemical reactions between polyphenols and key precursors of HAs.

Potential Role of Heterocyclic Aromatic Amines in Neurodegeneration

Heterocyclic aromatic amines (HAAs) are mainly formed in the pyrolysis process during high-temperature cooking of meat. Meat consumption is very typical of the western diet, and the amount of meat consumption in the eastern countries is growing rapidly; HAAs represents widespread exposure. HAAs are classified as possible human carcinogens; numerous epidemiological studies have demonstrated regular consumption of meat with HAAs as risk factor for cancers. Specific HAAs have received major attention. For example, 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine has been extensively studied as a genotoxicant and mutagen, with emergent literature on neurotoxicity. Harmane has been extensively studied for a role in essential tremors and potentially Parkinson's disease (PD). Harmane levels have been demonstrated to be elevated in blood and brain in essential tremor patients. Meat consumption has been implicated in the etiology of neurodegenerative diseases; however, the role of toxicants formed during meat preparation has not been studied. Epidemiological studies are currently examining the association between HAAs and risk of neurodegenerative diseases such as essential tremors and PD. Studies from our laboratory and others have provided strong evidence that HAA exposure produces PD and Alzheimer's disease-relevant neurotoxicity in cellular and animal models. In this review, we summarize and critically evaluate previous studies on HAA-induced neurotoxicity and the molecular basis of potential neurotoxic effects of HAAs. The available studies provide strong support for the premise that HAAs may impact neurological function and that addressing gaps in understanding of adverse neurological outcomes is critical to determine whether these compounds are modifiable risk factors.

Detection of heterocyclic amine (PhIP) by fluorescently labelled cucurbit[7]uril

A “host–guest” system for 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) detection was designed. This method might be the first quick measurement technique for HCA and may find wide application in food safety detection.

Formation and Prediction of PhIP, Harman, and Norharman in Chemical Model Systems Containing Epicatechin under Various Reaction Conditions

The aim of this study was to investigate the formation rules of 1-methyl-6-phenylimidazo[4,5-b]-pyridine (PhIP), 1-methyl-9H-pyrido[3,4-b]-indole (Harman), and 9H-pyrido[3,4-b]-indole (Norharman) in chemical model systems containing epicatechin under various reaction conditions and establish their prediction models. The results indicated that at 100-200 °C and pH 5.5-7.5 for 10-90 min, epicatechin inhibited the formation of PhIP, Harman, and Norharman by 32-100, 1-93, and 5-98%, respectively. The exponential growth equation in the growth model with R² of 0.986-0.997, the second-order equation in the polynomial model with R² of 0.900-0.949, and the trigonometric function equation in the Fourier model with R² of 0.513-0.926 were well fitted for the formation of PhIP, Harman, and Norharman at various temperatures, times, and pHs, respectively. The calibration set (R²c) and the prediction set (R²p) of the optimal partial least squares regression prediction model was 0.74 and 0.70 for PhIP, 0.75 and 0.70 for Harman, and 0.90 and 0.91 for Norharman, respectively. The results provide theoretical support to develop technologies or equipment for the real-time synchronous monitoring of PhIP, Harman, and Norharman during meat processing.

Selective Impedimetric Chemosensing of Carcinogenic Heterocyclic Aromatic Amine in Pork by dsDNA-Mimicking Molecularly Imprinted Polymer Film-Coated Electrodes

Inspired by the easy intercalation of quinoxaline heterocyclic aromatic amines (HAAs) in double-stranded DNA (dsDNA), we synthesized a nucleobase-functionalized molecularly imprinted polymer (MIP) as the recognition unit of an impedimetric chemosensor for the selective determination of a 2-amino-3,7,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (7,8-DiMeIQx) HAA. HAAs are generated in meat and fish processed at high temperatures. They are considered to be potent hazardous carcinogens. The MIP film was prepared by potentiodynamic electropolymerization of a pre-polymerization complex of two adenine- and one thymine-substituted bis(2,2'-bithien-5-yl)methane functional monomer molecules with one 7,8-DiMeIQx template molecule, in the presence of the 2,4,5,2',4',5'-hexa(thiophene-2-yl)-3,3'-bithiophene cross-linking monomer, in solution. The as-formed MIP chemosensor allowed for the selective impedimetric determination of 7,8-DiMeIQx in the 47 to 400 μM linear dynamic concentration range with a limit of detection of 15.5 μM. The chemosensor was successfully applied for 7,8-DiMeIQx determination in the pork meat extract as a proof of concept.

Chemical hazards in smoked meat and fish

This review aims to give an insight into the main hazards currently found in smoked meat and fish products. Literature research was carried out on international databases such as Access to Global Online Research in Agriculture (AGORA) database, Science direct, and Google scholar to collect and select 92 relevant publications included in this review. The smoking process was described and five hazards mostly found in smoked fish and meat were presented. The heat-induced compounds such as polycyclic aromatic hydrocarbons, heterocyclic amines, and nitrosamines were found in smoked fish and meat. Other hazards such as biogenic amines and heavy metals were also present in smoked fish and meat. The levels of these hazards reported from the literature exceeded the maximal limits of European Union. A brief description of risk assessment methodology applicable to such toxic compounds and risk assessment examples was also presented in this review. As most of the hazards reported in this review are toxic and even carcinogenic to humans, actions should be addressed to reduce their presence in food to protect consumer health and to prevent public health issue.

Heterocyclic Amine Formation and Mitigation in Processed Meat and Meat Products: A Mini-Review

ABSTRACT

This review provides an assessment of heterocyclic amine (HCA) formation and mitigation in processed meat and meat products. HCAs are formed when amino acids react with creatine during thermal processing of meat and meat products. The formation of HCAs depends on various factors, including the temperature, cooking time, fat contents, and presence of HCA precursors such as water, lipids, and marinades. Additional factors that could affect HCA formation are pH, meat type, and ingredients added during cooking such as antioxidants, amino acids, ions, fat, and sugars, which promote production of HCAs. 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline, 2-amino-3-methylimidazo-[4,5-f]quinoline, and 2-amino-3,4-dimethylimidazo[4,5-f]quinoline are HCAs of importance because of their link to cancer in humans. More than 25 HCAs have been identified in processed foods. Of these, nine HCAs are possible human carcinogens (group 2B) and one is a probable human carcinogen (group 2A). To mitigate HCA generation during heat processing, various techniques have been used, including recipe variations, adjustments of thermal processing conditions, addition of flavorings, pretreatments such as microwave heating, and addition of naturally occurring and artificial antioxidants.

HIGHLIGHTS

Inhibitory effects of hyperoside and quercitrin from Zanthoxylum bungeanum Maxim. leaf on 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine formation by trapping phenylacetaldehyde

2-amino-1-methyl-6-phenylimidazole[4,5-b]pyridine (PhIP) is one of the most abundant Heterocyclic amines (HAs) in meat products. Zanthoxylum bungeanum Maxim. leaf (ZML) extract has been shown to be rich in polyphenols, which are gaining increasing interest as efficient tools for inhibiting the formation of HAs. In the present work, the effects of ZML extract, major polyphenols, chlorogenic acid, hyperoside and quercitrin on the formation of PhIP in both roast beef patties and chemical model systems were investigated. UPLC-MS showed that ZML extract and those three polyphenols effectively inhibited PhIP formation. Additionally, GC-MS analysis showed that those three polyphenols significantly reduced the content of phenylacetaldehyde in the model systems, a key intermediate involved in PhIP formation. The subsequent UPLC-MS and TOF-MS/MS analysis found that hyperoside and quercitrin reacted with phenyacetaldehyde to form those four adducts, 8-C-(E-Phenylethenyl)hyperoside, 6-C-(E-Phenylethenyl)hyperoside, 8-C-(E-Phenylethenyl)quercitrin and 6-C-(E-Phenylethenyl)quercitrin, respectively. The results revealed that hyperoside and quercitrin could trap phenylacetaldehyde to form adducts, thereby, retarding the reaction of phenylacetaldehyde and creatinine, blocking the generation of PhIP.

Cyanidin-3-O-glucoside and its metabolite protocatechuic acid ameliorate 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) induced cytotoxicity in HepG2 cells by regulating apoptotic and Nrf2/p62 pathways

The present study investigated the protective effects and mechanism of action of cyanidin-3-O-glucoside (C3G) and its major metabolite protocatechuic acid (PCA) against 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) induced cytotoxicity in HepG2 cells. The results demonstrated that C3G and PCA dose-dependently suppressed PhIP-induced mutation in Salmonella typhimurium TA98, and inhibited PhIP-induced cytotoxicity and apoptosis in HepG2 cells. Western blot analysis indicated that C3G and PCA minimized PhIP-induced cell damage by reversing the abnormal expression of Bax/Bcl-2, Cytochrome c, cleaved Caspase-3, XIAP, Nrf2, HO-1, LC3 and p62 involved in intrinsic apoptotic and Nrf2/p62 pathways. Molecular docking results revealed that C3G and PCA were able to interfere with Nrf2 signaling and apoptotic cascade through binding to Keap1 and Bcl-2. Moreover, the protective effect of C3G was stronger than that of PCA. These findings suggested that dietary consumption of food sources rich in C3G can fight against the health risks of heterocyclic aromatic amines.

Determination of creatine, creatinine, free amino acid and heterocyclic aromatic amine contents of plain beef and chicken juices

In the present study, creatine, creatinine, free amino acid and heterocyclic aromatic amine (HAA) contents of plain beef and chicken juices were investigated. For this aim, the boned and boneless beef and chicken juices were obtained by boiling for 3 h at 100 °C without any additives in the laboratory. Creatine and creatinine content of the beef juices varied between 1.33-3.16 mg g^-1 and 1.29-1.42 mg g^-1, respectively, while creatine and creatinine content of the chicken juices varied between 0.98-1.63 mg g^-1 and 0.89-1.30 mg g^-1, respectively. The total free amino acid content in the beef juices and the chicken juices ranged between 14.61-20.65 mg 100 gdm^-1 and 19.66-57.88 mg 100 gdm^-1, respectively. None of the heterocyclic aromatic amines analyzed in the present study could be detected in the beef juices and the chicken juices. Therefore, the boned and boneless beef and chicken juice can be considered as safe from the standpoint of these HAAs and are suggested to use in the preparation of meals.

Dietary heterocyclic aromatic amine intake and cancer risk: epidemiological evidence from Japanese studies

Heterocyclic aromatic amines (HAAs), which are formed from the reaction of creatine or creatinine, amino acids, and sugars in meat and fish cooked at high temperatures, have been shown to be mutagenic in bacterial assays and carcinogenic in animal models. Following advances in the dietary assessment of HAA intake in epidemiological studies - including development of a validated meat-cooking module and a specialized food composition database - a number of epidemiological studies have specifically examined the association of HAA intake and cancer risk, most of which were conducted in Western countries. Given that dietary habits and cooking methods differ across countries, however, epidemiological investigation of dietary HAA intake requires a population-specific assessment method. Here, we developed a practical method for assessing dietary HAA intake among Japanese using a food frequency questionnaire (FFQ) and evaluated its validity for use in epidemiological studies by comparison with 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP) levels in human hair. The Japan Public Health Center-based Prospective Study reported that daily intake of HAAs among Japanese was relatively low, and that more than 50% of total intake in mainland Japan was derived from fish. Only four case-control studies in Japan have been reported so far, for colorectal, stomach and prostate cancer, and colorectal adenoma. A statistically significant positive association was found between 2-amino-3,4-dimethylimidazo [4,5-f] quinoline (MeIQ) and the risk of colorectal adenoma and between individual and total HAAs and the risk of prostate cancer. In contrast, no association was observed for colorectal or stomach cancer, or for colorectal adenoma among men. We also found that the limited and inconsistent findings among epidemiological studies are due to the difficulty in assessing exposure levels of HAAs. In addition to further evidence from prospective cohort studies in Japanese based on dietary HAA intake estimated by FFQs, studies using other methods to assess HAA exposure, such as biomarkers, are highly anticipated.

Effect of basil use in meatball production on heterocyclic aromatic amine formation

Herein, the effects of basil usage in meatball production on various quality criteria and heterocyclic aromatic amine (HAA) formation were investigated. The use of basil at every rate caused a significant reduction in TBARS value compared to control group. Cooking caused an increase in pH and TBARS values. IQx, IQ, AαC and MeAαC compounds could not be detected, while various amounts of MeIQx, MeIQ, 7,8-DiMeIQx, 4,8-DiMeIQx and PhIP were determined in the samples. Total HAA contents were determined up to 1.61 ng g^-1 and increasing of cooking temperature increased total HAA content, except for meatball with 1% basil. The reducing or enhancing effect of the use of basil in meatball production on the formation of HAA varied depending on the usage rate and cooking temperature. It was determined that even if 100 g of the meatballs containing 0.5% basil cooked at 250 °C whose total amount of HAA content was the highest, is eaten, the intake amount is far below 1 μg.

Metabolism and biomarkers of heterocyclic aromatic amines in humans

Heterocyclic aromatic amines (HAAs) form during the high-temperature cooking of meats, poultry, and fish. Some HAAs also arise during the combustion of tobacco. HAAs are multisite carcinogens in rodents, inducing cancer of the liver, gastrointestinal tract, pancreas, mammary, and prostate glands. HAAs undergo metabolic activation by N-hydroxylation of the exocyclic amine groups to produce the proposed reactive intermediate, the heteroaryl nitrenium ion, which is the critical metabolite implicated in DNA damage and genotoxicity. Humans efficiently convert HAAs to these reactive intermediates, resulting in HAA protein and DNA adduct formation. Some epidemiologic studies have reported an association between frequent consumption of well-done cooked meats and elevated cancer risk of the colorectum, pancreas, and prostate. However, other studies have reported no associations between cooked meat and these cancer sites. A significant limitation in epidemiology studies assessing the role of HAAs and cooked meat in cancer risk is their reliance on food frequency questionnaires (FFQ) to gauge HAA exposure. FFQs are problematic because of limitations in self-reported dietary history accuracy, and estimating HAA intake formed in cooked meats at the parts-per-billion level is challenging. There is a critical need to establish long-lived biomarkers of HAAs for implementation in molecular epidemiology studies designed to assess the role of HAAs in health risk. This review article highlights the mechanisms of HAA formation, mutagenesis and carcinogenesis, the metabolism of several prominent HAAs, and the impact of critical xenobiotic-metabolizing enzymes on biological effects. The analytical approaches that have successfully biomonitored HAAs and their biomarkers for molecular epidemiology studies are presented.

Neuromelanin Modulates Heterocyclic Aromatic Amine-Induced Dopaminergic Neurotoxicity

Heterocyclic aromatic amines (HAAs) are mutagens and potential human carcinogens. Our group and others have demonstrated that HAAs may also produce selective dopaminergic neurotoxicity, potentially relevant to Parkinson's disease (PD). The goal of this study was to elucidate mechanisms of HAA-induced neurotoxicity through examining a translational biochemical weakness of common PD models. Neuromelanin is a pigmented byproduct of dopamine metabolism that has been debated as being both neurotoxic and neuroprotective in PD. Importantly, neuromelanin is known to bind and potentially release dopaminergic neurotoxicants, including HAAs (eg, β-carbolines such as harmane). Binding of other HAA subclasses (ie, aminoimidazoaazarenes) to neuromelanin has not been investigated, nor has a specific role for neuromelanin in mediating HAA-induced neurotoxicity been examined. Thus, we investigated the role of neuromelanin in modulating HAA-induced neurotoxicity. We characterized melanin from Sepia officinalis and synthetic dopamine melanin, proposed neuromelanin analogs with similar biophysical properties. Using a cell-free assay, we demonstrated strong binding of harmane and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) to neuromelanin analogs. To increase cellular neuromelanin, we transfected SH-SY5Y neuroblastoma cells with tyrosinase. Relative to controls, tyrosinase-expressing cells exhibited increased neuromelanin levels, cellular HAA uptake, cell toxicity, and oxidative damage. Given that typical cellular and rodent PD models form far lower neuromelanin levels than humans, there is a critical translational weakness in assessing HAA-neurotoxicity. The primary impacts of these results are identification of a potential mechanism by which HAAs accumulate in catecholaminergic neurons and support for the need to conduct neurotoxicity studies in systems forming neuromelanin.

Red and processed meat consumption and cancer outcomes: Umbrella review

The purpose of this umbrella review was to evaluate the quality of evidence, validity and biases of the associations between red and processed meat consumption and multiple cancer outcomes according to existing systematic reviews and meta-analyses. The umbrella review identified 72 meta-analyses with 20 unique outcomes for red meat and 19 unique outcomes for processed meat. Red meat consumption was associated with increased risk of overall cancer mortality, non-Hodgkin lymphoma (NHL), bladder, breast, colorectal, endometrial, esophageal, gastric, lung and nasopharyngeal cancer. Processed meat consumption might increase the risk of overall cancer mortality, NHL, bladder, breast, colorectal, esophageal, gastric, nasopharyngeal, oral cavity and oropharynx and prostate cancer. Dose-response analyses revealed that 100 g/d increment of red meat and 50 g/d increment of processed meat consumption were associated with 11%-51% and 8%-72% higher risk of multiple cancer outcomes, respectively, and seemed to be not correlated with any benefit.

Is oven bag really advantageous in terms of heterocyclic aromatic amines and bisphenol-A? Chicken meat perspective

Herein, the effects of oven bag use belong to different brands on heterocyclic aromatic amine (HAA) formation and bisphenol-A (BPA) migration in cooked chicken meats (breast and leg) were investigated. Samples were also analyzed in terms of some qualitative properties (fatty acid profile, water, fat, pH, TBARS, cooking loss). Both oven bag use and meat type had an effect on qualitative properties of the samples. Total HAA amount changed between 6.53 and 42.32 ng/g, and HAA content was higher in breast meat. Total BPA content in samples cooked with oven bag ranged between non-quantified to 63.78 ng/g. Oven bag use reduced the total HAA amount at the rate of 12 - 68.82%, while it caused the BPA migration depends on the brand. However, it can be noted that the HAA and BPA levels were not at a level to pose a risk to human health in any of the samples.

An integrated method for monitoring thermal processing temperature of pork based on Q-Exactive mass spectrometry and chemometrics

Meat heating endpoint temperature (EPT) is an important indicator to ensure the safety of cooked meat. Accurately determining the EPT of cooked meat and ready-to-eat meat products is an important strategy to ensure food safety. In this study, a comprehensive metabolic method based on UPLC-Q Exactive and chemometrics was developed to study the metabolites differences among pork roasted at different temperatures in order to select markers indicating EPT and discover new toxic heat-induced compounds. A two-step extraction method was applied to avoid the loss of metabolite information caused by sample preparation. Using chemometrics, the five compounds of creatine, creatinine, 2-amino-1-methyl-6-phenylimidazo (4,5-b) pyridine (PhIP), 2-methyl-6-amino-5-hydroxymethylpyrimidine (TMP) and compound with the m/z of 114.04316 were selected as markers, and four of them were further confirmed by chemical standards. It is worth noting that TMP was discovered in roasted pork for the first time. In addition, targeting studies aimed at quantifying the selected markers were conducted at different thermal processing temperatures. From the quantification results, it can be concluded that the heat temperature not exceed 180 °C is recommended to reduce the content of toxic compounds. This study has proved that the integration of UPLC-Q Exactive and chemometrics could provide an efficient method for the study of markers related to thermal process and new toxic heat-induced compounds.

The function and mechanism of lactic acid bacteria in the reduction of toxic substances in food: a review

N-nitrosamines, heterocyclic amines, polycyclic aromatic hydrocarbons, biogenic amines, and acrylamide are widely distributed and some of the most toxic substances detected in foods. Hence, reduction of these substances has attracted worldwide attention. Lactic acid bacteria (LAB) inoculation has been found to be an effective way to reduce these toxic substances. In this paper, the reduction of toxic substances by LAB and its underlying mechanisms have been described through the review of recent studies. LAB aids this reduction via different mechanisms. First, it can directly decrease these harmful substances through adsorption or degradation. Peptidoglycans on the cell wall of LAB can bind to heterocyclic amines, acrylamide, and polycyclic aromatic hydrocarbons. Second, LAB can indirectly decrease the content of toxic substances by reducing their precursors. Third, antioxidant properties of LAB also contribute to the reduction in toxic substances. Finally, LAB can suppress the growth of amino acid decarboxylase-positive bacteria, thus reducing the accumulation of biogenic amines and N-nitrosamines. Therefore, LAB can contribute to the decrease in toxic substances in food and improve food safety. Further research on increasing the reduction efficiency of LAB and deciphering the mechanisms at a molecular level needs to be carried out to obtain the complete picture.

Shrimp as a substantial source of carcinogenic heterocyclic amines

In the present work, fifteen mutagenic/carcinogenic heterocyclicamines (HAs)were studied in cooked Caridean shrimp (pink) and Penaeid shrimp (tiger, white and brown). The cooking methods were used as stir-frying, broiling and steaming under controlled temperature and time, and HAs determination was performed by SPE/UPLC-ESI-MS/MS. HAs 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-Amino-1,6-dimethyl-imidazo[4,5-b]pyridine (DMIP), 1-Methyl-9H-pyrido[3,4-b]indole (Harman) and 9H-pyrido[3,4-b]indole (Norharman) were identified (0.05-22.48 ng/g) in all stir-fried and broiled shrimp, whereas 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) was only found (0.08-0.35 ng/g) in stir-fried shrimp. HAs 2-Amino-3,7,8-trimethyl-imidazo[4,5-f]quinoxaline (7,8-DiMeIQx) and, α-carbolines 2-Amino-9H-pyrido[2,3-b]indole (AαC) and 2-Amino-3-methyl-9H-pyrido[2,3-b]indole (MeAαC), γ-carbolines 3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-Amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) and δ-carbolines 2-Amino-6-methyldipyrido[1,2-α:3́,2́-d]imidazole (Glu-P-1) and 2-Aminodipyrido[1,2-α:3́,2́-d]imidazole (Glu-P-2) were not detected or found below quantification limit. Brown shrimp (stir-fried) appeared to be more contaminated which constitutes total HAs (81.93 ng/g) followed by pink (70.41 ng/g), tiger (53.02 ng/g) and white (33.57 ng/g). Steaming method does not yield any HAs, and the cause might be elucidate that shrimp were not directly in contact with cooking pan or fire which affect the HAs formation. Food precursors (protein, moisture, fat, creatine and glucose) were also measured in raw and cooked shrimp to investigate the influence on HAs formation. Creatine (3.85 mg/g) and glucose (0.43 mg/g) were found at higher concentrations in brown shrimp, generates high amounts of HAs. Our findings have illustrated that the cooking method, shrimp types and precursors are the main contributors to the formation of HAs. The outcomes from this work could be applied to estimate the HAs human intake globally and add to steaming cooking method in such types of food products that diminish the risk of HAs exposure, and thus to get healthier food quality and security.

The presence of polycyclic aromatic hydrocarbons and heterocyclic aromatic amines in barbecued meatballs formulated with different animal fats

The formations of polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic amines (HAAs) in barbecued meatballs formulated with different animal fats [beef intermuscular and/or sheep tail (ST)] were investigated. Meatballs were also analyzed in terms of some qualitative and quantitative properties. From perspective of nutrition, meatballs formulated with ST fat at level 10% contained the highest ratios of linoleic acid (2.29%), ∑PUFA (2.52%), and ∑PUFA/∑SFA (0.05). Animal fat type had no significant effect on total HAAs amount of the samples and total HAAs amount was ranged between 1.35 and 2.91 ng/g. On the other hand, the usage of different animal fat significantly affected amount of BaP and PAH4, and the levels of BaP and PAH4 were ranged between 2.33-4.30 and 8.41-15.48 ng/g, respectively. From perspective of health risk, it can be noted that the meatballs formulated with ST fat at level 10% are more risky due to their total amounts of food toxicants.

Environmental exposures and the etiopathogenesis of Alzheimer's disease: The potential role of BACE1 as a critical neurotoxic target

Alzheimer's disease (AD) is a major public health crisis due to devastating cognitive symptoms, a lack of curative treatments, and increasing prevalence. Most cases are sporadic (>95% of cases) after the age of 65 years, implicating an important role of environmental factors in disease pathogenesis. Environmental neurotoxicants have been implicated in neurodegenerative disorders including Parkinson's Disease and AD. Animal models of AD and in vitro studies have shed light on potential neuropathological mechanisms, yet the biochemical and molecular underpinnings of AD-relevant environmental neurotoxicity remain poorly understood. Beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) is a potentially critical pathogenic target of environmentally induced neurotoxicity. BACE1 clearly has a critical role in AD pathophysiology: It is required for amyloid beta production and expression and activity of BACE1 are increased in the AD brain. Though the literature on BACE1 in response to environmental insults is limited, current studies, along with extensive AD neurobiology literature suggest that BACE1 deserves attention as an important neurotoxic target. Here, we critically review research on environmental neurotoxicants such as metals, pesticides, herbicides, fungicides, polyfluoroalkyl substances, heterocyclic aromatic amines, advanced glycation end products, and acrolein that modulate BACE1 and potential mechanisms of action. Though more research is needed to clearly understand whether BACE1 is a critical mediator of AD-relevant neurotoxicity, available reports provide convincing evidence that BACE1 is altered by environmental risk factors associated with AD pathology, implying that BACE1 inhibition and its use as a biomarker should be considered in AD management and research.

Preparation of a Broad-Spectrum Heterocyclic Aromatic Amines (HAAs) Antibody and Its Application in Detection of Eight HAAs in Heat Processed Meat

Heterocyclic aromatic amines (HAAs) are potential human mutagens and carcinogens mainly generated in heat-treated meat. In this work, a broad-spectrum HAAs antibody was prepared and used to develop an indirect competitive ELISA (ic-ELISA) for simultaneous determination of eight HAAs, including 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f] quinoline (MeIQ), 2-amino-3-methylimidazo[4,5-f]quinoxaline (IQx), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline (7,8-DiMeIQx), 2-amino-3,4,7,8-tetramethylimidazo[4,5-f]quinoxaline (4,7,8-TriMeIQx), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in grilled and fried meat samples. The limit of detection (LOD, calculated as IC₁₀) and 50% inhibition concentration (IC₅₀) of ic-ELISA were 5.29 μg/L and 99.08 μg/L, respectively. The detection results of this ic-ELISA were in good agreement with the detection results of UPLC-MS/MS in real samples, which indicated that this ic-ELISA can be applied to detect the total content of eight HAAs in heat processed meat. Use of a broad-spectrum antibody is an efficient strategy in developing immunoassay for simultaneous measuring food risk factors with similar structure.

Neuromelanin formation exacerbates HAA-induced mitochondrial toxicity and mitophagy impairments

Parkinson's disease (PD) is a progressive neurodegenerative disorder that is a major public health concern due in part to prevalence, debilitating symptoms, and links to environmental exposures. Much research has focused on environmental factors that may lead to dopaminergic neurotoxicity that occurs in PD. In the study of neuronal uptake and neurotoxicity, critical species differences have been observed. For example, neuromelanin is a molecule formed in part by the breakdown products of dopamine metabolism, along with lipid and protein components. Interestingly, human catecholaminergic neurons contain readily detectable amounts of neuromelanin, while rodent models form far lower levels of neuromelanin that is barely detectable. This discrepancy is potentially an important translational weakness. Recently, we showed that neuromelanin formation modulates heterocyclic aromatic amine (HAA)-induced neurotoxicity in cellular models. HAAs are dietary toxins that have primarily been studied as carcinogens, with emergent literature on selective neurotoxicity. The goal of the present study was to identify whether mitochondria in neuromelanin forming cells may be especially sensitive to HAAs. Here, we exposed galactose-supplemented SH-SY5Y cells to HAAs and tested mitochondrial function and mitophagy. The ectopic formation of neuromelanin was found to increase mitochondrial oxidative stress, decrease membrane potential, increase mitochondrial bioenergetic impairments, and impair mitophagy relative to HAA-treated cells that do not form neuromelanin. These results suggest that neuromelanin has a critical role in HAA toxicity and adverse effects on mitochondria. The data also further cement the need to conduct both mechanistic and risk assessment studies on PD-relevant neurotoxicity in models that form neuromelanin.