Acrolein metabolites, diabetes and insulin resistance

Ultra-processed foods - a scoping review for Nordic Nutrition Recommendations 2023

Ultra-processed foods (UPFs) are increasingly consumed worldwide and have been linked to several chronic diseases. This paper aims to describe the totality of the available evidence regarding UPFs in relation to health-related outcomes as a basis for setting food-based dietary guidelines for the Nordic Nutrition Recommendations 2023. Systematic literature searches were conducted to identify systematic reviews, meta-analyses, randomized controlled trials (RCTs), and prospective cohort studies examining the association between UPF intake and non-communicable diseases or mortality. A total of 12 systematic reviews (including five meta-analyses) and 44 original research studies (43 prospective cohort studies and one RCT) were included. All original research studies were deemed to be of good methodological quality. The current evidence supports that greater consumption of UPFs is associated with weight gain and increased risk of obesity, cardiovascular disease, type 2 diabetes, and all-cause mortality. The available literature also supports an association between UPFs and hypertension, cancer, and depression; however, the limited number of studies and subjects investigated preclude strong conclusions. Due to the highly diverse nature of UPFs, additional studies are warranted, with special emphasis on disentangling mediating mechanisms, whether nutritional or non-nutrient based. Nevertheless, the available evidence regarding UPFs in relation to weight gain, CVD, type 2 diabetes, and all-cause mortality is considered strong enough to support dietary recommendations to limit their consumption.

Ferroptosis: Mechanisms and role in diabetes mellitus and its complications

Diabetes mellitus (DM) and its complications are major diseases that affect human health and pose a serious threat to global public health. Although the prevention and treatment of DM and its complications are constantly being revised, optimal treatment strategies remain unavailable. Further exploration of new anti-diabetic strategies is an arduous task. Revealing the pathological changes and molecular mechanisms of DM and its complications is the cornerstone for exploring new therapeutic strategies. Ferroptosis is a type of newly discovered iron-dependent regulated cell death. Notably, the role of ferroptosis in the occurrence, development, and pathogenesis of DM and its complications has gradually been revealed. Numerous studies have shown that ferroptosis plays an important role in the pathophysiology and pathogenesis of DM and its associated complications. The aim of this review is to discuss the known underlying mechanisms of ferroptosis, the relationship between ferroptosis and DM, and the relationship between ferroptosis as a mode of cell death and diabetic kidney disease, diabetic retinopathy, diabetic cardiomyopathy, diabetic osteoporosis, diabetes-associated cognitive dysfunction, DM-induced erectile dysfunction, and diabetic atherosclerosis.

Increased Levels of Urine Volatile Organic Compounds Are Associated With Diabetes Risk and Impaired Glucose Homeostasis

CONTEXT

Volatile organic compounds (VOCs) are pervasive environmental pollutants that have been linked to various adverse health effects. However, the effect of ambient VOCs, whether individually or in mixtures, on diabetes remains uncertain and requires further investigation.

OBJECTIVE

This study investigates the effects of ambient VOCs exposure, whether single or mixed, on diabetes mellitus and glucose homeostasis in the general population.

METHODS

Urinary concentrations of VOC metabolites were obtained from the National Health and Nutrition Examination Survey. Survey-weighted logistic regression and generalized linear regression were used to explore the associations between individual VOC exposure and diabetes risk and glucose homeostasis indicators, respectively. Weighted quantile sum (WQS) regression models were applied to assess the combined effects of VOC mixtures.

RESULTS

Out of 8468 participants, 1504 had diabetes mellitus. Eight VOC metabolites showed positive associations with diabetes mellitus (OR, 1.15-1.43; all P < .05), insulin resistance (IR) (OR, 1.02-1.06; P < .05), and other glucose homeostasis indicators (β, 0.04-2.32; all P < .05). Mixed VOC models revealed positive correlations between the WQS indices and diabetes risk (OR = 1.52; 95% CI, 1.29-1.81), IR (OR = 1.36; 95% CI, 1.14-1.62), and other glucose homeostasis indicators (β, 0.17-2.22; all P < .05).

CONCLUSION

Urinary metabolites of ambient VOCs are significantly associated with an increased diabetes risk and impaired glucose homeostasis. Thus, primary prevention policies aimed at reducing ambient VOCs could attenuate diabetes burden.

Associations of individual and mixture exposure to volatile organic compounds with metabolic syndrome and its components among US adults

BACKGROUND

People are exposed to various volatile organic compounds (VOCs) in their environment. Our study aims to examine the links between VOCs exposure and metabolic syndrome (MetS) and its components, as well as identify critical VOCs.

METHOD

In this study, we enrolled 8223 adults from the National Health and Nutrition Examination Survey (NHANES) and analyzed 15 kinds of urinary VOCs metabolites. The Spearman correlation model, generalized linear regression model, restricted cubic spline (RCS), weighted quantile sum (WQS) analysis, and Bayesian kernel machine regression (BKMR) were used to evaluate the association between individual VOC/VOCs mixture and MetS as well as its components.

RESULTS

In generalized linear regression model, compared to the lowest quartile of urinary VOCs metabolites, the highest quartiles of urinary VOC metabolites were positively associated with MetS including N-Acetyl-S-(N-methylcarbamoyl)-l-cysteine (AMCC) (OR: 1.22, 95%CI: 1.00, 1.49), N-Acetyl-S-(2-carboxyethyl)-l-cysteine (CEMA) (OR: 1.71, 95%CI: 1.41, 2.07), N-Acetyl-S-(3-hydroxypropyl)-l-cysteine (3HPMA) (OR: 1.32, 95%CI: 1.11, 1.63), and N-Acetyl-S-(3-hydroxypropyl-1-methyl)-l-cysteine (HMPMA) (OR: 1.34, 95%CI: 1.09, 1.64). Consistent results were found in the dose-response relationship in RCS model. Results of WQS showed that VOCs mixture was positively associated with MetS (OR: 1.16, 95%CI: 1.06, 1.28), elevated WC (OR: 1.25, 95%CI: 1.13, 1.37), elevated FBG (OR: 1.24, 95%CI: 1.12, 1.37), elevated TG (OR: 1.34, 95%CI: 1.21, 1.49), and reduced HDL-C (OR: 1.20, 95%CI: 1.09, 1.33). However, the WQS index was negatively associated with elevated BP (OR: 0.81; 95%CI: 0.70, 0.94). BKMR analysis confirmed that the urinary VOCs mixture was positively associated with MetS, elevated WC, elevated TG, reduced HDL-C, elevated FBG, but negatively associated with elevated BP. CEMA was defined as the most heavily weighted chemical in the WQS and BKMR models.

CONCLUSION

Our findings suggested that exposure to specific VOC or VOCs mixture is associated with the higher risk of MetS and its components, except for elevated BP.

β-escin activates ALDH and prevents cigarette smoke-induced cell death

BACKGROUND

The tobacco use is one of the biggest public health threats worldwide. Cigarette smoke contains over 7000 chemicals among other aldehydes, regarded as priority toxicants. β-escin (a mixture of triterpenoid saponins extracted from the Aesculus hippocastanum. L) is a potent activator of aldehyde dehydrogenase (ALDH) - an enzyme catalyzing oxidation of aldehydes to non-toxic carboxylic acids.

PURPOSE

The aim of this study was to evaluate the effect of β-escin on ALDH activity, ALDH isoforms mRNA expression and cytotoxicity in nasal epithelial cells exposed to cigarette smoke extract (CSE).

METHODS

Nasal epithelial cells from healthy non-smokers were treated with β-escin (1 µM) and exposed to 5% CSE. After 6- or 24-hours of stimulation cell viability, DNA damage, ALDH activity and mRNA expression of ALDH isoforms were examined.

RESULTS

24 h β-escin stimulation revised CSE induced cytotoxicity and DNA damage. Cells cultured with β-escin or exposed to CSE responded with strong increase in ALDH activity. This effect was more pronounced in cultures treated with combination of β-escin and CSE. The strongest stimulatory effect on ALDH isoform mRNA expression was observed in cells cultured simultaneously with β-escin and CSE: at 6 h for ALDH1A1 and ALDH3A1, and at 24 h for ALDH1A3, ALDH3A2, ALDH3B1, and ALDH18A1. Combined β-escin and CSE treatment prevented the CSE-induced inhibition of ALDH2 expression at 24 h.

CONCLUSIONS

β-escin is an effective ALDH stimulatory and cytoprotective agent and might be useful in the prevention or supportive treatment of tobacco smoke-related diseases.

Ultra-processed Food Intake and Risk of Type 2 Diabetes in Korean Adults

BACKGROUND

Several studies from the United States and European countries reported a positive association between ultra-processed food intake and diabetes risk. However, little is known about the association in Asian populations. It is also unknown about the individual ultra-processed food items that are most unfavorably associated with diabetes risk.

OBJECTIVE

We examined the associations of ultra-processed food intake (combined, as well as individual ultra-processed food items) with the risk of type 2 diabetes.

METHODS

This prospective analysis included 7438 participants aged 40-69 y from the Korean Genome and Epidemiology Study Ansan-Ansung cohort. Dietary intake was assessed at baseline using a 103-item semiquantitative food-frequency questionnaire. Ultra-processed foods were classified using the Nova definition. Incident type 2 diabetes cases were identified via follow-up interviews and health examination. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), adjusting for potential confounders.

RESULTS

During the follow-up (2001-2019; median: 15 y), a total of 1187 type 2 diabetes cases were identified. Compared with the lowest quartile of ultra-processed food intake, the highest quartile was positively associated with diabetes risk [HR (95% CI) = 1.34 (1.13, 1.59), P-trend = 0.002]. The association did not change after additional adjustment for diet quality or BMI. Among individual ultra-processed food items, a higher consumption of ham/sausage [per 1% increase in the weight ratio: HR (95% CI) = 1.40 (1.05, 1.86)], instant noodles [1.07 (1.02, 1.11)], ice cream [1.08 (1.03, 1.13)], and carbonated beverages [1.02 (1.00, 1.04)] were associated with an increased risk of type 2 diabetes, whereas a higher intake of candy/chocolate was associated with a decreased risk [0.78 (0.62, 0.99)].

CONCLUSIONS

Our data suggest that the high intake of ultra-processed foods, particularly ham/sausage, instant noodles, ice cream, and carbonated beverages, is associated with an increased risk of type 2 diabetes in Korean adults.

Serum metabolome and liver transcriptome reveal acrolein inhalation-induced sex-specific homeostatic dysfunction

Acrolein, a respiratory irritant, induces systemic neuroendocrine stress. However, peripheral metabolic effects have not been examined. Male and female WKY rats were exposed to air (0 ppm) or acrolein (3.16 ppm) for 4 h, followed by immediate serum and liver tissue collection. Serum metabolomics in both sexes and liver transcriptomics in males were evaluated to characterize the systemic metabolic response. Of 887 identified metabolites, > 400 differed between sexes at baseline. An acrolein biomarker, 3-hydroxypropyl mercapturic acid, increased 18-fold in males and 33-fold in females, indicating greater metabolic detoxification in females than males. Acrolein exposure changed 174 metabolites in males but only 50 in females. Metabolic process assessment identified higher circulating free-fatty acids, glycerols, and other lipids in male but not female rats exposed to acrolein. In males, acrolein also increased branched-chain amino acids, which was linked with metabolites of nitrogen imbalance within the gut microbiome. The contribution of neuroendocrine stress was evident by increased corticosterone in males but not females. Male liver transcriptomics revealed acrolein-induced over-representation of lipid and protein metabolic processes, and pathway alterations including Sirtuin, insulin-receptor, acute-phase, and glucocorticoid signaling. In sum, acute acrolein inhalation resulted in sex-specific serum metabolomic and liver transcriptomic derangement, which may have connections to chronic metabolic-related diseases.

Examining the proportions of food addiction among women with and without polycystic ovarian syndrome who do and do not take hormonal birth control

Polycystic ovarian syndrome (PCOS) is a reproductive disorder driven by insulin resistance. Insulin resistance may increase weight gain and increase the rewarding intake of ultra-processed foods (UPFs). Individuals with PCOS may be more susceptible to the reinforcing properties of UPFs, increasing the risk to consume UPFs in addictive-like ways, operationalized by food addiction (FA). Additionally, hormonal birth control, commonly prescribed to women with PCOS, are found to increase food cravings and overeating. This study examined the relationships between PCOS status, FA, and hormonal birth control use. The study sample (N = 365, assigned female at birth) was drawn from Amazon Mechanical Turk, with half of the sample (n = 181) reporting having PCOS and the other half not (n = 184). Participants answered questions about women's reproductive health (i.e., PCOS, hormonal birth control use) and completed the modified Yale Food Addiction Scale 2.0 (mYFAS 2.0). A chi-square test found that 51.9 % of participants with PCOS (M = 6.23, SD = 3.82) met diagnostic criteria for FA (assessed by the mYFAS 2.0) compared to 16.8 % of participants without PCOS (M = 2.47, SD = 3.39). A hierarchical linear regression found independent main effects of PCOS status (β = 0.40, t(352) = 8.61, p < .001) and hormonal birth control use (β = 0.16, t(351) = 3.59, p < .001), to be associated with higher mYFAS symptom count scores. No differences were found between the types of hormonal birth control participants reported taking. The finding suggests that FA is an overlooked, understudied psychological condition impacting these individuals in weight loss treatments. Future studies are needed to understand the relationship between FA and PCOS in clinical samples.

Acrolein induces mitochondrial dysfunction and insulin resistance in muscle and adipose tissues in vitro and in vivo

Type 2 diabetes mellitus (DM) is a common chronic condition characterized by persistent hyperglycemia and is associated with insulin resistance (IR) in critical glucose-consuming tissues, including skeletal muscle and adipose tissue. Oxidative stress and mitochondrial dysfunction are known to play key roles in IR. Acrolein is a reactive aldehyde found in the diet and environment that is generated as a fatty acid product through the glucose autooxidation process under hyperglycemic conditions. Our previous studies have shown that acrolein impairs insulin sensitivity in normal and diabetic mice, and this effect can be reversed by scavenging acrolein. This study demonstrated that acrolein increased oxidative stress and inhibited mitochondrial respiration in differentiated C2C12 myotubes and differentiated 3T3-L1 adipocytes. As a result, insulin signaling pathways were inhibited, leading to reduced glucose uptake. Treatment with acrolein scavengers, N-acetylcysteine, or carnosine ameliorated mitochondrial dysfunction and inhibited insulin signaling. Additionally, an increase in acrolein expression correlated with mitochondrial dysfunction in the muscle and adipose tissues of diabetic mice. These findings suggest that acrolein-induced mitochondrial dysfunction contributes to IR, and scavenging acrolein is a potential therapeutic approach for treating IR.

The association of the serum levels of aldehydes with diabetes-related eye diseases: a cross-sectional population-based study

Diabetes could impact many ocular tissues. However, the association of the serum aldehydes with diabetes-related eye diseases (DED) remains unclear. Thus, we aimed to examine the above relationship from the general US population of 2013-2014 National Health and Nutrition Examination Survey (NHANES). The multivariable logistic regression and Bayesian kernel machine regression (BKMR) were used to analyze the effect of serum aldehydes on the risk of DED. Pearson's correlation analysis, the restricted cubic spline (RCS) model, and the linear regression were performed to explore the association between the serum aldehydes and other parameters. The multivariable linear regression was conducted to further underlie the relationship between the serum aldehydes and the glycohemoglobin A1c (HbA1c) in DED participants. Although no significant association was observed between the serum aldehydes and the risk of DED by the multivariable logistic regression and BKMR, the Pearson correlation revealed a positive association between the HbA1c level and the serum level of heptanaldehyde and isopentanaldehyde in DED participants. The RCS model confirmed the above linear correlation. After adjusting for the cofounding factor of smoking, the multivariable linear regression revealed a significant association between the serum level of heptanaldehyde and the HbA1c level in DED participants. Our results suggest that aldehyde exposure did not significantly increase the risk of DED, while heptanaldehyde was the risk factor for increased HbA1c in DED population.

Synergistic Inhibitory Effect of Multiple Polyphenols from Spice on Acrolein during High-Temperature Processing

Acrolein (ACR) is a toxic unsaturated aldehyde that is produced during food thermal processing. Here, we investigated the synergistic effect of polyphenols in binary, ternary, and quaternary combinations on ACR by the Chou-Talalay method, and then explored the synergistic effect of cardamonin (CAR), alpinetin (ALP), and pinocembrin (PIN) in fixed proportion from Alpinia katsumadai Hayata (AKH) combined with curcumin (CUR) in the model, and roasted pork using LC-MS/MS. Our results showed that their synergistic effect depended on the intensification of their individual trapping ACR activities, which resulted in the formation of more ACR adducts. In addition, by adding 1% AKH (as the carrier of CAR, ALP, and PIN) and 0.01% CUR (vs. 6% AKH single) as spices, more than 71.5% (vs. 54.0%) of ACR was eliminated in roast pork. Our results suggested that selective complex polyphenols can synergistically remove the toxic ACR that is produced in food processing.

Urinary metabolites of multiple volatile organic compounds, oxidative stress biomarkers, and gestational diabetes mellitus: Association analyses

Volatile organic compounds are ubiquitous in the environment, which may cause various adverse health effects. The objectives of this study were to investigate associations of single and mixture of urinary metabolites of volatile organic compounds (mVOCs) with gestational diabetes mellitus (GDM) risk, and examine the possible role of oxidative stress in the associations. This nested case-control study included 454 GDM cases and 454 healthy controls matched by maternal age and infant sex. Urinary concentrations of twenty-one mVOCs and three oxidative stress biomarkers (including 8-OHdG, 8-OHG, and HNEMA), in early pregnancy were measured. Analyses using logistic regression model showed that an interquartile range increase in urinary concentrations of six individual mVOCs (ATCA, BPMA, CEMA, 3HPMA, MU, and TGA) were significantly associated with increased odds of GDM by 19-27%. Weighted quantile sum regression analyses showed that in each quartile increment of the mixture of mVOCs, the odds of GDM increased by 39% (95% CI: 16%, 67%), with 2-aminothiazoline-4-carboxylic acid weighted the most in the associations (weight: 25%). Furthermore, significant associations of the oxidative stress biomarkers with both GDM and certain mVOCs were observed. These results suggested that certain urinary mVOCs (correspondingly, the parent VOCs such as 1-bromopropane, cyanide, and benzene should be concerned as priority ones for regulation and policy making) in early pregnancy were significantly associated with elevated GDM incidence, and the associations were potentially related with oxidative stress biomarkers.

Acrolein Exposure Impaired Glucose Homeostasis and Increased Risk of Type 2 Diabetes: An Urban Adult Population-Based Cohort Study with Repeated Measures

Acrolein is an identified high-priority hazardous air pollutant ubiquitous in daily life and associated with cardiometabolic risk that attracts worldwide attention. However, the etiology role of acrolein exposure in glucose dyshomeostasis and type 2 diabetes (T2D) is unclear. This repeated-measurement prospective cohort study included 3522 urban adults. Urine/blood samples were repeatedly collected for determinations of acrolein metabolites (N-acetyl-S-(3-hydroxypropyl)-l-cysteine, N-acetyl-S-(2-carboxyethyl)-l-cysteine; acrolein exposure biomarkers), glucose homeostasis, and T2D at baseline and a three-year follow-up. We found that each 3-fold increment in acrolein metabolites was cross-sectionally associated with 5.91-6.52% decrement in homeostasis model assessment-insulin sensitivity (HOMA-IS) and 0.07-0.14 mmol/L, 4.02-4.57, 5.91-6.52, 19-20, 18-19, and 23-31% increments in fasting glucose (FPG), fasting insulin (FPI), HOMA-insulin resistance (HOMA-IR), risks of prevalent IR, impaired fasting glucose (IFG), and T2D, respectively; longitudinally, participants with sustained-high acrolein metabolite levels had increased risks of incident IR, IFG, and T2D by 63-80, 87-99, and 120-154%, respectively (P < 0.05). In addition, biomarkers of heme oxygenase-1 activity (exhaled carbon monoxide), lipid peroxidation (8-iso-prostaglandin-F2α), protein carbonylation (protein carbonyls), and oxidative DNA damage (8-hydroxy-deoxyguanosine) mediated 5.00-38.96% of these associations. Our study revealed that acrolein exposure may impair glucose homeostasis and increase T2D risk via mediating mechanisms of heme oxygenase-1 activation, lipid peroxidation, protein carbonylation, and oxidative DNA damage.

Diet as a Source of Acrolein: Molecular Basis of Aldehyde Biological Activity in Diabetes and Digestive System Diseases

Acrolein, a highly reactive α,β-unsaturated aldehyde, is a compound involved in the pathogenesis of many diseases, including neurodegenerative diseases, cardiovascular and respiratory diseases, diabetes mellitus, and the development of cancers of various origins. In addition to environmental pollution (e.g., from car exhaust fumes) and tobacco smoke, a serious source of acrolein is our daily diet and improper thermal processing of animal and vegetable fats, carbohydrates, and amino acids. Dietary intake is one of the main routes of human exposure to acrolein, which is a major public health concern. This review focuses on the molecular mechanisms of acrolein activity in the context of its involvement in the pathogenesis of diseases related to the digestive system, including diabetes, alcoholic liver disease, and intestinal cancer.

Pyruvate kinase M2 modification by a lipid peroxidation byproduct acrolein contributes to kidney fibrosis

Renal fibrosis is a hallmark of diabetic nephropathy (DN) and is characterized by an epithelial-to-mesenchymal transition (EMT) program and aberrant glycolysis. The underlying mechanisms of renal fibrosis are still poorly understood, and existing treatments are only marginally effective. Therefore, it is crucial to comprehend the pathophysiological mechanisms behind the development of renal fibrosis and to generate novel therapeutic approaches. Acrolein, an α-,β-unsaturated aldehyde, is endogenously produced during lipid peroxidation. Acrolein shows high reactivity with proteins to form acrolein-protein conjugates (Acr-PCs), resulting in alterations in protein function. In previous research, we found elevated levels of Acr-PCs along with kidney injuries in high-fat diet-streptozotocin (HFD-STZ)-induced DN mice. This study used a proteomic approach with an anti-Acr-PC antibody followed by liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis to identify several acrolein-modified protein targets. Among these protein targets, pyruvate kinase M2 (PKM2) was found to be modified by acrolein at Cys358, leading to the inactivation of PKM2 contributing to the pathogenesis of renal fibrosis through HIF1α accumulation, aberrant glycolysis, and upregulation of EMT in HFD-STZ-induced DN mice. Finally, PKM2 activity and renal fibrosis in DN mice can be reduced by acrolein scavengers such as hydralazine and carnosine. These results imply that acrolein-modified PKM2 contributes to renal fibrosis in the pathogenesis of DN.

Ultra-Processed Food Consumption and Increased Risk of Metabolic Syndrome in Adults: The ELSA-Brasil

OBJECTIVE

To investigate the association between ultra-processed food (UPF) consumption and the incidence of metabolic syndrome (MetS).

RESEARCH DESIGN AND METHODS

From 2008 to 2010, we enrolled 15,105 adults, aged 35-74 years, who were employees from six public education and research institutions to assemble the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). We used a food frequency questionnaire to assess UPF consumption (measured in grams per day) at baseline. We then assessed the outcomes of those returning to visits between 2012 and 2014 and between 2017 and 2019. We defined incident MetS by the presence of at least three of the following five abnormalities: high fasting glucose level, high triglyceride level, low HDL cholesterol level, high blood pressure, and abdominal obesity, after excluding those meeting such criteria at baseline. We also excluded those who had missing data or an implausible energy intake, leaving 8,065 participants in the study.

RESULTS

The median age was 49 years, 59% of participants were women, and the median consumption of UPFs was 366 g/day. After 8 years, there were 2,508 new cases of MetS. In robust Poisson regression, adjusting for sociodemographics, behavioral factors, and energy intake, we found a 7% (relative risk [RR] 1.07; 95% CI 1.05-1.08) higher risk of incident MetS for an increase of 150 g/day in UPF consumption. Similarly, those in the fourth quartile (compared with the first quartile) had a 33% increased risk (RR 1.33; 95% CI 1.20-1.47). Further adjustment for BMI attenuated these associations (for 150 g/day increases in UPF consumption and for the fourth quartile compared to the first one, respectively, RR = 1.04, 95% CI 1.02-1.06; RR = 1.19, 95% CI 1.07-1.32).

CONCLUSIONS

Greater consumption of UPFs is associated with an increased risk of MetS. These findings have important implications for diabetes and cardiovascular disease prevention and management.

Glutathione S-Transferase P1 Genetic Variant's Influence on the HbA1c Level in Type Two Diabetic Patients

GST (glutathione S-transferases) are capable of influencing glucose homeostasis, probably through regulation of the response to oxidant stress. The aim of our study was to investigate the relationship between GSTP1 gene polymorphism and glycated hemoglobin (HbA1c) levels in type two diabetic (T2D) patients. A total of 307 T2D patients were included. Analysis of the GSTP1 gene polymorphism (rs1695) was conducted using the TaqMan qPCR method endpoint genotyping. HbA1c was determined using a COBAS 6000 autoanalyzer. A univariable linear regression and multivariable linear regression model were used to investigate the association between mean HbA1c level and GSTP1 gene polymorphism, age at T2D diagnosis, T2D duration, therapy with insulin, gender, BMI, smoking status. GSTP1 Val/Val genotype, age at T2D diagnosis, T2D duration and therapy with insulin were statistically significant contributors to HbA1c levels (p < 0.05). Multivariable regression analysis revealed that GSTP1 (Val/Val vs. Ile/Ile) was associated with higher HbA1c even after adjustment for variables that showed a statistically significant relationship with HbA1c in univariable analyses (p = 0.024). The results suggest that GSTP polymorphism may be one of the risk factors for higher HbA1c in T2D patients. Our study is limited by the relatively small sample size, cross-sectional design, and lack of inclusion of other oxidative stress-related genetic variants.

Ultra-processed foods and human health: from epidemiological evidence to mechanistic insights

Epidemiological studies have suggested a role for ultra-processed foods in numerous chronic inflammatory diseases such as inflammatory bowel diseases and metabolic syndrome. Preclinical and clinical studies are accumulating to better decipher the effects of various aspects of food processing and formulation on the aetiology of chronic, debilitating inflammatory diseases. In this Review, we provide an overview of the current data that highlight an association between ultra-processed food consumption and various chronic diseases, with a focus on epidemiological evidence and mechanistic insights involving the intestinal microbiota.

Common Chemical Pollutants Causing a Lot of Ill Health

Due to industrialization and inadequate controls on release of manufacturing chemicals into the environment and into the products being made, the entire population is constantly being exposed to a wide variety of chemical pollutants. The key question, of course, is their safety. The most acutely damaging ones have been progressively limited. However, virtually all safety research is on single toxins and very little of it looks at the impact of chronic exposure, especially chronic exposure to multiple chemicals simultaneously. This editorial discusses the clinical significance of 4 of the chemicals (acrolein, acrylamide, perchlorate, and phthalates) found most often in samples doctors send to labs for analysis. The research clearly demonstrates that these chemicals in a dose-dependent manner disrupt physiology, impair health, and increase risk for common diseases.

Ultra-processed Foods Consumption Increases the Risk of Hypertension in Adults: A Systematic Review and Meta-analysis

BACKGROUND

Effect of ultra-processed foods (UPFs) consumption on health has attracted widespread attention in recent years. However, the relationship between UPFs consumption and hypertension is unclear. This meta-analysis was conducted to analyze the above association.

METHODS

We systematically searched PubMed, Embase, and Cochrane Library for all relevant studies published up to 31 January 2022 without language limitation. The random-effects model was selected to pool the effect sizes and 95% confidence intervals (CIs).

RESULTS

Nine observational studies involving 111,594 participants were included. Results from this meta-analysis showed that higher UPFs consumption significantly increased the risk of hypertension (odds ratio: 1.23; 95% CI: 1.11, 1.37; P = 0.034). Furthermore, analyses were performed based on gender, study design, exposure assessment, outcome assessment, body mass index, energy intake, and physical activity, which suggested that the results remained statistically significant.

CONCLUSIONS

Our findings suggested that UPFs might have detrimental effects on the incidence of hypertension in the general population. Although current evidence is limited, it cannot be denied that reducing consumption of UPFs may contribute to decrease the risk of chronic noncommunicable diseases.

Acrolein plays a culprit role in the pathogenesis of diabetic nephropathy in vitro and in vivo

OBJECTIVE

Diabetic nephropathy (DN), also known as diabetic kidney disease (DKD), is a major chronic complication of diabetes and is the most frequent cause of kidney failure globally. A better understanding of the pathophysiology of DN would lead to the development of novel therapeutic options. Acrolein, an α,β-unsaturated aldehyde, is a common dietary and environmental pollutant.

DESIGN

The role of acrolein and the potential protective action of acrolein scavengers in DN were investigated using high-fat diet/ streptozotocin-induced DN mice and in vitro DN cellular models.

METHODS

Acrolein-protein conjugates (Acr-PCs) in kidney tissues were examined using immunohistochemistry. Renin-angiotensin system (RAS) and downstream signaling pathways were analyzed using quantitative RT-PCR and Western blot analyses. Acr-PCs in DN patients were analyzed using an established Acr-PC ELISA system.

RESULTS

We found an increase in Acr-PCs in kidney cells using in vivo and in vitro DN models. Hyperglycemia activated the RAS and downstream MAPK pathways, increasing inflammatory cytokines and cellular apoptosis in two human kidney cell lines (HK2 and HEK293). A similar effect was induced by acrolein. Furthermore, acrolein scavengers such as N-acetylcysteine, hydralazine, and carnosine could ameliorate diabetes-induced kidney injury. Clinically, we also found increased Acr-PCs in serum samples or kidney tissues of DKD patients compared to normal volunteers, and the Acr-PCs were negatively correlated with kidney function.

CONCLUSIONS

These results together suggest that acrolein plays a role in the pathogenesis of DN and could be a diagnostic marker and effective therapeutic target to ameliorate the development of DN.

Xenobiotics Delivered by Electronic Nicotine Delivery Systems: Potential Cellular and Molecular Mechanisms on the Pathogenesis of Chronic Kidney Disease

Chronic kidney disease (CKD) is characterized as sustained damage to the renal parenchyma, leading to impaired renal functions and gradually progressing to end-stage renal disease (ESRD). Diabetes mellitus (DM) and arterial hypertension (AH) are underlying diseases of CKD. Genetic background, lifestyle, and xenobiotic exposures can favor CKD onset and trigger its underlying diseases. Cigarette smoking (CS) is a known modified risk factor for CKD. Compounds from tobacco combustion act through multi-mediated mechanisms that impair renal function. Electronic nicotine delivery systems (ENDS) consumption, such as e-cigarettes and heated tobacco devices, is growing worldwide. ENDS release mainly nicotine, humectants, and flavorings, which generate several byproducts when heated, including volatile organic compounds and ultrafine particles. The toxicity assessment of these products is emerging in human and experimental studies, but data are yet incipient to achieve truthful conclusions about their safety. To build up the knowledge about the effect of currently employed ENDS on the pathogenesis of CKD, cellular and molecular mechanisms of ENDS xenobiotic on DM, AH, and kidney functions were reviewed. Unraveling the toxic mechanisms of action and endpoints of ENDS exposures will contribute to the risk assessment and implementation of proper health and regulatory interventions.

Cross-sectional and longitudinal associations of acrolein exposure with pulmonary function alteration: Assessing the potential roles of oxidative DNA damage, inflammation, and pulmonary epithelium injury in a general adult population

BACKGROUND

Acrolein is a significant high priority hazardous air pollutant with pulmonary toxicity and the leading cause of most noncancer adverse respiratory effects among air toxics that draws great attention. Whether and how acrolein exposure impacts pulmonary function remain inconclusive.

OBJECTIVES

To assess the association of acrolein exposure with pulmonary function and the underlying roles of oxidative DNA damage, inflammation, and pulmonary epithelium integrity.

METHODS

Among 3,279 Chinese adults from the Wuhan-Zhuhai cohort, associations of urinary acrolein metabolites (N-Acetyl-S-(2-carboxyethyl)-L-cysteine, CEMA; N-Acetyl-S-(3-hydroxypropyl)-L-cysteine, 3HPMA) as credible biomarkers of acrolein exposure with pulmonary function were analyzed by linear mixed models. Joint effects of biomarkers of oxidative DNA damage (8-hydroxy-deoxyguanosine), inflammation (C-reactive protein, CRP), and pulmonary epithelium integrity (Club cell secretory protein, CC16) with acrolein metabolites on pulmonary function and the mediating roles of these biomarkers were assessed. Besides, a subgroup (N = 138) was randomly recruited from the cohort to assess the stabilities of acrolein metabolites and their longitudinal associations with pulmonary function change in three years.

RESULTS

Significant inverse dose-response relationships between acrolein metabolites and pulmonary function were found. Each 10-fold increment in CEMA, 3HPMA, or ΣUACLM (CEMA + 3HPMA) was cross-sectionally related to a 68.56-, 40.98-, or 46.02-ml reduction in FVC and a 61.54-, 43.10-, or 50.14-ml reduction in FEV₁, respectively (P < 0.05). Furthermore, acrolein metabolites with fair to excellent stabilities were found to be longitudinally associated with pulmonary function decline in three years. Joint effects of acrolein metabolites with 8-hydroxy-deoxyguanosine, CRP, and CC16 on pulmonary function were identified. CRP significantly mediated 5.97% and 5.51% of CEMA-associated FVC and FEV₁ reductions, respectively. 8-hydroxy-deoxyguanosine significantly mediated 6.78%, 6.88%, and 7.61% of CEMA-, 3HPMA-, and ΣUACLM-associated FVC reductions, respectively.

CONCLUSIONS

Acrolein exposure of general adults was cross-sectionally and longitudinally related to pulmonary function decline, which was aggravated and/or partly mediated by oxidative DNA damage, inflammation, and pulmonary epithelium injury.

Origin and Fate of Acrolein in Foods

Acrolein is a highly toxic agent that may promote the occurrence and development of various diseases. Acrolein is pervasive in all kinds of foods, and dietary intake is one of the main routes of human exposure to acrolein. Considering that acrolein is substantially eliminated after its formation during food processing and re-exposed in the human body after ingestion and metabolism, the origin and fate of acrolein must be traced in food. Focusing on molecular mechanisms, this review introduces the formation of acrolein in food and summarises both in vitro and in vivo fates of acrolein based on its interactions with small molecules and biomacromolecules. Future investigation of acrolein from different perspectives is also discussed.

Dual effects of cardamonin/alpinetin and their acrolein adducts on scavenging acrolein and the anti-bacterial activity from Alpinia katsumadai Hayata as a spice in roasted meat

Acrolein (ACR) is frequently produced by the thermal degradation of carbohydrates and amino acids and lipid peroxidation in the thermal processing of food. Long-term exposure to ACR can cause various chronic diseases. Here, we screened two high-temperature-resistant ACR inhibitors, cardamonin (CAR) and alpinetin (ALP), which can interconvert without any loss at 100 °C, and were obtained from Alpinia katsumadai Hayata (AKH). They demonstrated the best activity among the six spices investigated and could scavenge ACR generated in roasted pork by forming adducts. After three ACR adducts were prepared, namely CAR-ACR-1, CAR-ACR-2 and ALP-ACR, quantitative analysis showed that the amount of CAR-ACR-1 generated in lean roasted pork with 2% AKH addition reached the minimal inhibitory concentration against Escherichia coli and Staphylococcus aureus, which was 20 times lower than that of CAR, and the higher the generation of ACR, the stronger its antibacterial activity. These results provided well-defined evidence to promote the application of AKH to ACR inhibitors in food processing.

Metabolic Investigation on the Interaction Mechanism between Dietary Dihydrochalcone Intake and Lipid Peroxidation Product Acrolein Reduction

SCOPE

Acrolein (ACR), a lipid peroxidation product, pathologically participates in various chronic diseases. In vitro evidence suggestes that dietary dihydrochalcones (DHCs) potentiate safe and alternative therapeutics to synthetic pharmaceuticals for ACR scavenging. Here, to investigate whether ingested DHCs could trap ACR and thereof result in reductions in endogenous ACR in mice is aimed.

METHODS AND RESULTS

Three doses of phloretin (25, 100, and 400 mg kg-1 ), a major dietary DHC, are orally administrated to mice and 24 h urine and fecal samples are collected, respectively. High-resolution MS-based targeted metabolomics reveal for the first time that phloretin and its oxidized metabolite are able to trap endogenous ACR via formation of ACR conjugates. Quantification further demonstrate that a) more than 13% of ingested phloretin can dose-dependently trap 0.77-9.92 nmol of ACR within 24 h; b) phloretin ingestion leads to marked reductions in both free ACR and ACR metabolites in mouse urine compared to control; and c) trapping reactions by phloretin can account for up to 20.1% of the total decreases in endogenous ACR, depending on the administration doses.

CONCLUSION

Findings from this study indicate that regular consumption of DHCs-rich diets holds great promise to alleviate the development of ACR-associated chronic diseases.

The role of endogenous versus exogenous sources in the exposome of putative genotoxins and consequences for risk assessment

The “totality” of the human exposure is conceived to encompass life-associated endogenous and exogenous aggregate exposures. Process-related contaminants (PRCs) are not only formed in foods by heat processing, but also occur endogenously in the organism as physiological components of energy metabolism, potentially also generated by the human microbiome. To arrive at a comprehensive risk assessment, it is necessary to understand the contribution of in vivo background occurrence as compared to the ingestion from exogenous sources. Hence, this review provides an overview of the knowledge on the contribution of endogenous exposure to the overall exposure to putative genotoxic food contaminants, namely ethanol, acetaldehyde, formaldehyde, acrylamide, acrolein, α,β-unsaturated alkenals, glycation compounds, N-nitroso compounds, ethylene oxide, furans, 2- and 3-MCPD, and glycidyl esters. The evidence discussed herein allows to conclude that endogenous formation of some contaminants appears to contribute substantially to the exposome. This is of critical importance for risk assessment in the cases where endogenous exposure is suspected to outweigh the exogenous one (e.g. formaldehyde and acrolein).

The association of aldehydes exposure with diabetes mellitus in US population: NHANES 2013-2014

BACKGROUND

The association of mixed aldehydes exposure with diabetes remains unclear.

OBJECTIVE

We aimed to explore associations between serum aldehydes concentration and diabetes.

METHODS

We analyzed associations between aldehydes and diabetes using data from 1795 participants in the National Health and Nutrition Examination Survey (NHANES) from 2013 to 2014 by multiple logistic regression models. Bayesian kernel machine regression (BKMR) was used to evaluate the combined association of serum aldehydes on prediabetes and diabetes.

RESULTS

Isopentanaldehyde increased the risk of diabetes 2.09 fold (95%CI:1.05-4.16) in the highest tertile, compared to the lowest-tertile concentration after adjusting for covariates, with a p-value for trend (P-t) equal to 0.041, in females. The adjusted OR of prediabetes with a 95% CI for the highest tertile was 0.52(0.28, 0.97) for benzaldehyde in females (P-t = 0.034). We also found associations in the male group between butyraldehyde and diabetes for the second (OR:2.80, 95%CI:1.35-5.79) and third (OR:2.59, 95%CI:1.30-5.17) tertile levels (P-t = 0.010). The risk of diabetes increased 2.55 fold (95%CI: 1.26-5.16, P-t = 0.008), in subjects in the highest tertile of hexanaldehyde concentration. Other aldehydes did not show a statistically significant association with diabetes or prediabetes. The BKMR model showed a positive association of mixed aldehydes with diabetes in males, and butyraldehyde showed a significant positive trend with the highest posterior inclusion probability (PIP = 0.85). Mixed aldehydes increased female's risk from prediabetes to diabetes in which isopentanaldehyde had the highest posterior inclusion probability (PIP = 0.67).

CONCLUSIONS

The mixed aldehydes might increase the risk of suffering from diabetes in males and accelerate the progression of diabetes in females, in which butyraldehyde and isopentanaldehyde play the most important roles.

Resveratrol protected acrolein-induced ferroptosis and insulin secretion dysfunction via ER-stress- related PERK pathway in MIN6 cells

Acrolein is a typical food and environmental pollutant and a risk factor for diabetes. The primary pathogenesis of diabetes is insulin deficiency and resistance. Ferroptosis is an iron-dependent cell death type, accompanying by lipid peroxide accumulation. Here, 25 μM acrolein-induced ferroptosis is observed in mouse pancreatic β-cell MIN6 cells as indicated by ferroptosis-related indicators, including GPX4 exhaustion, lipid peroxides accumulation, and insulin secretion impairment. Additionally, acrolein-induced ferroptosis could be reversed by Ferrostatin-1. Furthermore, endoplasmic reticulum stress (ER stress) is involved in acrolein-induced ferroptosis. The ER stress inhibits the expression of PPARγ, an essential gene in glucose and lipid metabolism, and facilitates lipid peroxide accumulation, leading to MIN6 cells ferroptosis and dysfunction. Moreover, resveratrol, an antioxidant natural product, may relieve ER stress and upregulate PPARγ expression, thereby inhibiting acrolein-induced ferroptosis. Thus, this study demonstrated a new perspective for the cytotoxic mechanism of acrolein on pancreatic β-cell and the protective effect of resveratrol.

Urinary acrolein metabolites, systemic inflammation, and blood lipids: Results from the National Health and Nutrition Examination Survey

Exposure to acrolein was reported to be related with adverse health effects. However, the associations between acrolein exposure and blood lipids remain largely unknown. We assessed the associations of urinary acrolein metabolites with blood lipids using data from the National Health and Nutrition Examination Survey (NHANES) and further investigated the existence of mediation by systemic inflammation in the associations. Urinary acrolein metabolites, N-acetyl-S-(carboxyethyl)-l-cysteine (CEMA) and N-acetyl-S-(3-hydroxypropyl)-l-cysteine (3-HPMA), blood lipids, and serum high sensitivity C-reactive protein (hs-CRP) were measured in the NHANES. The associations of urinary acrolein metabolites with blood lipids and dyslipidemia and hs-CRP were estimated by multiple linear and logistic regression models. Mediation analysis was conducted to evaluate the mediating effects of hs-CRP on the associations between urinary acrolein metabolites and blood lipids. We found urinary CEMA+3-HPMA (∑acrolein) was significantly associated with higher levels of serum triglycerides (TG), hs-CRP, and lower levels of high-density lipoprotein cholesterol (HDL-C). Each 1-unit increment in ln-transformed level of ∑acrolein was associated with a 0.06 mmol/L increment in TG and 0.02 mmol/L decrement in HDL-C (all P <0.05). A positive dose-response relationship was observed between urinary ∑acrolein and dyslipidemia risk. In addition, hs-CRP significantly mediated the associations of urinary ∑acrolein with serum TG and HDL-C, with mediated proportions of 22.12% and 41.41%, respectively. In conclusion, acrolein exposure is associated with the levels of serum TG, HDL-C, and hs-CRP. Hs-CRP may mediate acrolein-associated alterations of blood lipids. Our results indicated that decreased exposure to acrolein may reduce systemic inflammation and dyslipidemia risk.

Ultra-Processed Food Consumption and Adult Diabetes Risk: A Systematic Review and Dose-Response Meta-Analysis

(1) Background: Recent individual studies have demonstrated that consumption of ultra-processed food (UPF) may be related to type two diabetes mellitus (T2DM). We aimed to synthesize the results from these individual studies by conducting an updated systematic review and meta-analysis of observational studies evaluating the association between UPF consumption and the risk of T2DM. (2) Methods: A systematic search was conducted using ISI Web of Science, PubMed/MEDLINE and Scopus electronic databases from inception up to August 2021. Data were extracted from five studies (one cross-sectional study and four cohort studies, totaling 230,526 adults from four different countries). Risk ratios (RR) of pooled results were estimated using a random-effects model. (3) Results: Our results revealed that higher UPF consumption was significantly associated with an increased risk of T2DM (RR = 1.74; 95% CI: 1.36, 2.22; I² = 68.9%; p < 0.001; n = 5). Linear dose-response analysis indicated that each 10% increase in UPF consumption (kcal/d) was associated with a 15% higher risk of T2DM (RR = 1.15; 95% CI: 1.06, 1.26; I² = 86.0%; p < 0.001; n = 5) among adults. Non-linear dose-response analysis demonstrated a positive linear association between UPF consumption and T2DM (p_nonlinearity = 0.13, p_{dose-response} < 0.001; n = 5) among adults. (4) Conclusions: A higher intake of UPF was significantly associated with an increased risk of T2DM. However, underlying mechanisms remain unknown and future experimental studies are warranted.

Interconversion and Acrolein-Trapping Capacity of Cardamonin/Alpinetin and Their Metabolites In Vitro and In Vivo

People are at high risk of exposure to endogenous and exogenous acrolein (ACR). ACR can cause a multitude of illnesses, including cardiovascular disease, Alzheimer's disease, and diabetes. In this study, we investigated the reaction pathway of cardamonin (CAR) or alpinetin (ALP) with ACR and the interconversion of CAR and ALP in vitro at 37 °C in phosphate-buffered saline using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Subsequently, ACR adducts of CAR, ALP, and their metabolites, for example, CAR-ACR-1, ALP-ACR, mono-ACR-pinocembrin chalcone (PIN-ACR), and mono- and di-ACR-naringenin (NAR-ACR and NAR-2ACR), were detected in urine samples, but only CAR-ACR-1 and ALP-ACR were detected in fecal samples from the CAR- and ALP-treated mouse groups using ultraperformance liquid chromatography-MS/MS, respectively. Quantitative analyses showed that CAR, ALP, and their metabolites markedly scavenged ACR in a dose-dependent manner in vivo. Furthermore, we also found that the metabolites of CAR or ALP remained and promoted the ACR-trapping ability.

Inhibitory Effect on Acrolein by Cyanidin-3-O-glucoside and Its Acrolein Adducts from the Pigment of Mynica Red

Acrolein (ACR), the simplest α,β-unsaturated aldehyde, possesses high reactivity and toxicity both in vitro and in vivo and results in various chronic diseases. This has attracted increasing interest from researchers to screen various bioactive compounds to control it. In this article, we attempted to discover a new attribute of cyanidin-3-O-glucoside (C3G), including its ACR-scavenging capacity, reaction pathway, and possible application. Our findings revealed that C3G could capture ACR to form mono- and diadducts at room temperature by using liquid chromatography-mass spectrometry, and we further synthesized and elucidated the structures of C3G-ACR and C3G-2ACR using HRMS and 2D NMR. The structural data validated that there were two active sites of C3G for trapping ACR: at C-6 in the A-ring and C-5' in the B-ring. In addition, we found that C3G-ACR exhibited a more remarkable clearing ability than C3G within a short time. More than 65.9% of ACR was eliminated by C3G-ACR within 5 min via further formation of C3G-2ACR, but there was no obvious effect of C3G on ACR. When the incubation time was extended to 120 min, C3G could remove up to 83.2% of ACR. Subsequently, we also observed that mynica red (>5% C3G), as a pigmented food additive, could efficiently eliminate ACR generated in the Chinese liquor model and real red bayberry wine products to form C3G-ACR and C3G-2ACR. Both adducts increased significantly, by 10 times to a 100 times, after adding mynica red to red bayberry wine products for 24 h; they also increased rapidly with prolonged incubation time in the liquor-mynica red model system. Therefore, our findings suggest that C3G or mynica red may be developed as a promising novel ACR inhibitor in fruit wine and assembled alcoholic drinks or as a health food.

Reduced Acrolein Detoxification in akr1a1a Zebrafish Mutants Causes Impaired Insulin Receptor Signaling and Microvascular Alterations

Increased acrolein (ACR), a toxic metabolite derived from energy consumption, is associated with diabetes and its complications. However, the molecular mechanisms are mostly unknown, and a suitable animal model with internal increased ACR does not exist for in vivo studying so far. Several enzyme systems are responsible for acrolein detoxification, such as Aldehyde Dehydrogenase (ALDH), Aldo-Keto Reductase (AKR), and Glutathione S-Transferase (GST). To evaluate the function of ACR in glucose homeostasis and diabetes, akr1a1a-/- zebrafish mutants are generated using CRISPR/Cas9 technology. Accumulated endogenous acrolein is confirmed in akr1a1a-/- larvae and livers of adults. Moreover, a series of experiments are performed regarding organic alterations, the glucose homeostasis, transcriptome, and metabolomics in Tg(fli1:EGFP) zebrafish. Akr1a1a-/- larvae display impaired glucose homeostasis and angiogenic retina hyaloid vasculature, which are caused by reduced acrolein detoxification ability and increased internal ACR concentration. The effects of acrolein on hyaloid vasculature can be reversed by acrolein-scavenger l-carnosine treatment. In adult akr1a1a-/- mutants, impaired glucose tolerance accompanied by angiogenic retina vessels and glomerular basement membrane thickening, consistent with an early pathological appearance in diabetic retinopathy and nephropathy, are observed. Thus, the data strongly suggest impaired ACR detoxification and elevated ACR concentration as biomarkers and inducers for diabetes and diabetic complications.

Low-Dose Acrolein, an Endogenous and Exogenous Toxic Molecule, Inhibits Glucose Transport via an Inhibition of Akt-Regulated GLUT4 Signaling in Skeletal Muscle Cells

Urinary acrolein adduct levels have been reported to be increased in both habitual smokers and type-2 diabetic patients. The impairment of glucose transport in skeletal muscles is a major factor responsible for glucose uptake reduction in type-2 diabetic patients. The effect of acrolein on glucose metabolism in skeletal muscle remains unclear. Here, we investigated whether acrolein affects muscular glucose metabolism in vitro and glucose tolerance in vivo. Exposure of mice to acrolein (2.5 and 5 mg/kg/day) for 4 weeks substantially increased fasting blood glucose and impaired glucose tolerance. The glucose transporter-4 (GLUT4) protein expression was significantly decreased in soleus muscles of acrolein-treated mice. The glucose uptake was significantly decreased in differentiated C2C12 myotubes treated with a non-cytotoxic dose of acrolein (1 μM) for 24 and 72 h. Acrolein (0.5–2 μM) also significantly decreased the GLUT4 expression in myotubes. Acrolein suppressed the phosphorylation of glucose metabolic signals IRS1, Akt, mTOR, p70S6K, and GSK3α/β. Over-expression of constitutive activation of Akt reversed the inhibitory effects of acrolein on GLUT4 protein expression and glucose uptake in myotubes. These results suggest that acrolein at doses relevant to human exposure dysregulates glucose metabolism in skeletal muscle cells and impairs glucose tolerance in mice.

Pre-Gestational Consumption of Ultra-Processed Foods and Risk of Gestational Diabetes in a Mediterranean Cohort. The SUN Project

We aimed to investigate the relationship between the pre-gestational consumption of ultra-processed foods (UPF) and the risk of gestational diabetes (GDM). We carried out a prospective study among 3730 Spanish women of the SUN cohort who reported at least one pregnancy after baseline recruitment. Cases of GDM were identified among women with a confirmed diagnosis of GDM. UPF consumption was assessed through a validated, semi-quantitative food frequency questionnaire and the frequency of UPF consumption was categorized in tertiles. We identified 186 cases of GDM. In the pooled sample, we did not observe a significant association of UPF with the risk of GDM. When we stratified by age, the multivariate OR for the third tertile of UPF consumption compared with the lowest one was 2.05 (95% CI 1.03, 4.07) in women aged ≥30 years at baseline (P_trend = 0.041). The association remained significant in a sensitivity analysis after changing many of our assumptions and adjusting for additional confounders. No association between a higher UPF consumption and GDM risk was observed in women aged 18–29 years. The pre-gestational UPF consumption may be a risk factor for GDM, especially in women aged 30 years or more. Confirmatory studies are needed to validate these findings.

N-acetylcysteine is more effective than ellagic acid in preventing acrolein induced dysfunction in mitochondria isolated from rat liver

Acrolein, a common environmental, food, and water pollutant, has been linked to the pathology of several diseases. This toxic substance is an unsaturated aldehyde and a major component of cigarette smoke and also produced during the processing of fat-containing foods. This study aimed to evaluate the protective effect of ellagic acid and N-acetylcysteine (NAC) in acrolein-induced toxicity in mitochondria isolated from the rat liver. The mitochondria were exposed to different concentrations of acrolein for 40 min, then functionality was assessed. Contact with acrolein rapidly and remarkably depleted the intracellular glutathione and antioxidant capacity, because of increased ROS production and lipid peroxidation which may lead to the cell death. Mitochondria were then pre-exposed to different concentrations of ellagic acid, NAC, and IC₅₀ concentration of acrolein. Consistent with the results, acrolein decreased GSH content and increased ROS level and lipid peroxidation, which led to ATP depletion and mitochondrial dysfunction. While ellagic acid has been able to reduce ROS and therefore the permeability of the mitochondrial membrane potential (MMP), presumably via its antioxidant properties, we've not detected its favorable effect on GSH and ATP restoration and also on mitochondrial complex II function. However, NAC strongly decreased ROS, lipid peroxidation and MMP and improved GSH content and complex II activity. These results showed that ellagic acid while reported to possess some cellular protective properties, did not prevent mitochondria from being affected by acrolein during this in vitro study. PRACTICAL APPLICATIONS: Ellagic acid is found in fruits, vegetables, and nuts which are revealed to possess strong antioxidant and protective properties. Mitochondrial dysfunction has been implicated in the pathogenesis of some chronic diseases including cancer, diabetes, liver disease, and neurodegenerative disorders, and presumably, ellagic acid by its mitochondrial protective effects can be helpful in these chronic conditions. Acrolein is an α,β-unsaturated aldehyde that can be produced during cooking at high temperature. By increasing the ROS level and lipid peroxidation and depleting the glutathione content, acrolein induces cellular damage and mitochondrial toxicity. This toxicant is taken into account as a carcinogen and mutagen. In this study, the protective effect of ellagic acid in comparison with N-acetylcysteine has been investigated during the toxicity of acrolein in the rat liver mitochondria to look for evidence of whether it is useful or not through this insult.

Impact of ultra-processed food consumption on metabolic health

PURPOSE OF REVIEW

Ultra-processed foods (UPF) have been associated with poor diet quality and adverse health outcomes. Our aim in this review is to summarize recent research assessing the impact of UPF consumption, classified according to the NOVA system, on outcomes related to metabolic health.

RECENT FINDINGS

Thirty recent studies with different design, quality and target population have investigated the impact of UPF consumption on parameters related to metabolic health, which were organized into: metabolic syndrome; body weight change and obesity indicators; blood pressure and hypertension; glucose profile, insulin resistance and type 2 diabetes; other metabolic risks and cardiovascular diseases and mortality. Most of the studies demonstrated adverse associations between high UPF consumption and metabolic health, mainly those with robust design and involving adults.

SUMMARY

Most of the latest findings have revealed an adverse impact of high UPF consumption on metabolic health, including cardiovascular diseases and mortality. Scientific evidence is accumulating towards the necessity of curbing UPF consumption worldwide at different life stages. Nevertheless, other studies are needed to confirm the causality between UPF consumption and metabolic health in diverse scenarios and to better elucidate all likely mechanisms involved in this relationship.

Impacto do consumo de alimentos ultraprocessados na saúde de crianças, adolescentes e adultos: revisão de escopo

O objetivo deste trabalho foi realizar uma revisão de escopo da literatura acerca da associação entre o consumo de alimentos ultraprocessados e desfechos em saúde. A busca foi realizada nas bases PubMed, Web of Science e LILACS. Foram elegíveis os estudos que avaliaram a associação entre o consumo de alimentos ultraprocessados identificados com base na classificação NOVA e os desfechos em saúde. O processo de revisão resultou na seleção de 63 estudos, os quais foram analisados em termos de qualidade com base em ferramenta do Instituto Nacional de Saúde dos Estados Unidos. Os desfechos encontrados incluíram indicadores de obesidade, marcadores de risco metabólico, diabetes, doenças cardiovasculares, câncer, asma, depressão, fragilidade, doenças gastrointestinais e mortalidade. A evidência foi particularmente consistente para obesidade (ou indicadores relacionados a ela) em adultos, cuja associação com o consumo de ultraprocessados foi demonstrada, com efeito dose-resposta, em estudos transversais com amostras representativas de cinco países, em quatro grandes estudos de coorte e em um ensaio clínico randomizado. Grandes estudos de coorte também encontraram associação significativa entre o consumo de alimentos ultraprocessados e o risco de doenças cardiovasculares, diabetes e câncer, mesmo após ajuste para obesidade. Dois estudos de coorte demonstraram associação do consumo de alimentos ultraprocessados com depressão e quatro estudos de coorte com mortalidade por todas as causas. Esta revisão sumarizou os resultados de trabalhos que descreveram a associação entre o consumo de alimentos ultraprocessados e as diversas doenças crônicas não transmissíveis e seus fatores de risco, o que traz importantes implicações para a saúde pública.

Disease-associated acrolein: A possible diagnostic and therapeutic substrate for in vivo synthetic chemistry

Acrolein, a highly reactive α,β-unsaturated aldehyde, is a compound to which humans are exposed in many different situations and often causes various human diseases. This paper summarizes the reports over the past twenty-five years regarding disease-associated acrolein detected in clinical patients and the role acrolein plays in various diseases. In several diseases, it was found that the increased acrolein acts as a pathogenetic factor. Thus, we propose the utility of over-produced acrolein as a substrate for a promising therapeutic or diagnostic method applicable to a wide range of diseases based on an in vivo synthetic chemistry strategy.

Application of systematic evidence mapping to assess the impact of new research when updating health reference values: A case example using acrolein

BACKGROUND

The environmental health community needs transparent, methodologically rigorous, and rapid approaches for updating human health risk assessments. These assessments often contain reference values for cancer and/or noncancer effects. Increasingly, the use of systematic review methods are preferred when developing these assessments. Systematic evidence maps are a type of analysis that has the potential to be very helpful in the update process, especially when combined with machine-learning software advances designed to expedite the process of conducting a review.

OBJECTIVES

To evaluate the applicability of evidence mapping to determine whether new evidence is likely to result in a change to an existing health reference value, using inhalation exposure to the air pollutant acrolein as a case example.

METHODS

New literature published since the 2008 California Environmental Protection Agency's Office of Environmental Health Hazard Assessment (OEHHA) Reference Exposure Level (REL) for acrolein was assessed. Systematic review methods were used to search the literature and screening included the use of machine-learning software. The Populations, Exposures, Comparators and Outcomes (PECO) criteria were kept broad to identify studies that characterized acute and chronic exposure and could be informative for hazard characterization. Studies that met the PECO criteria after full-text review were briefly summarized before their suitability for chronic point of departure (POD) derivation and calculation of a reference value was considered. Studies considered potentially suitable underwent a targeted evaluation to determine their suitability for use in dose-response analysis.

RESULTS

Over 15,000 studies were identified from scientific databases. Both machine-learning and manual screening processes were used to identify 60 studies considered PECO-relevant after full-text review. Most of these PECO-relevant studies were short-term exposure animal studies (acute or less than 1 month of exposure) and considered less suitable for deriving a chronic reference value when compared to the subchronic study in rats used in the 2008 OEHHA assessment. Thirteen epidemiological studies were identified but had limitations in the exposure assessment that made them less suitable for dose-response compared to the subchronic rat study. Among the 13 studies, there were four controlled trial studies that have the potential to be informative for future acute reference value derivation. Thus, the 2008 subchronic rat study used by OEHHA appears to still be the most appropriate study for chronic reference value derivation. In addition, advances in dosimetric modeling for gases, including new evidence pertinent to acrolein, could be considered when updating existing acrolein toxicity values.

CONCLUSIONS

Evidence mapping is a very useful tool to assess the need for updating an assessment based on understanding the potential impact of new studies on revising an existing health reference value. In this case example, the focus was to identify studies suitable for chronic exposure dose-response analysis, while also identifying studies that may be important to consider for acute exposure scenarios, hazard identification, or for future research. This allows the evidence map to be a useful resource for a range of decision-making contexts. Specialized systematic review software increased the efficiency of the process in terms of human resources and time to conduct the analysis.

Regulation of Spermine Oxidase through Hypoxia-Inducible Factor-1α Signaling in Retinal Glial Cells under Hypoxic Conditions

Purpose

Acrolein, a highly reactive unsaturated aldehyde, is known to facilitate glial cell migration, one of the pathological hallmarks in diabetic retinopathy. However, cellular mechanisms of acrolein generation in retinal glial cells remains elusive. In the present study, we investigated the role and regulation of spermine oxidase (SMOX), one of the enzymes related to acrolein generation, in retinal glial cells under hypoxic condition.

Methods

Immunofluorescence staining for SMOX was performed using sections of fibrovascular tissues obtained from patients with proliferative diabetic retinopathy. Expression levels of polyamine oxidation enzymes including SMOX were analyzed in rat retinal Müller cell line 5 (TR-MUL5) cells under either normoxic or hypoxic conditions. The transcriptional activity of Smox in TR-MUL5 cells was evaluated using the luciferase assay. Levels of acrolein-conjugated protein, Nε-(3-formyl-3,4-dehydropiperidino) lysine adduct (FDP-Lys), and hydrogen peroxide were measured.

Results

SMOX was localized in glial cells in fibrovascular tissues. Hypoxia induced SMOX production in TR-MUL5 cells, which was suppressed by silencing of hypoxia-inducible factor-1α (Hif1a), but not Hif2a. Transcriptional activity of Smox was regulated through HIF-1 binding to hypoxia response elements 2, 3, and 4 sites in the promoter region of Smox. Generation of FDP-Lys and hydrogen peroxide increased in TR-MUL5 cells under hypoxic condition, which was abrogated by SMOX inhibitor MDL72527.

Conclusions

The current data demonstrated that hypoxia regulates production of SMOX, which plays a role in the generation of oxidative stress inducers, through HIF-1α signaling in Müller glial cells under hypoxic condition.

Mechanistic studies of inhibition on acrolein by myricetin

Acrolein (ACR) is an unsaturated aldehyde with high activity and toxicity and is produced in vivo and in food. This study investigated the impact of B-ring structure on the trapping of ACR by flavonols and the trapping mechanism and efficacy of ACR by myricetin. Galangin, kaempferol, quercetin, and myricetin, which possess the same A- and C-ring but different numbers of -OH groups on the B-ring, were selected for this study. Our results suggested that increasing the number of -OH groups on the B-ring can enhance the ACR trapping efficacy of flavonol and myrectin was identified as the most active flavonol. The adducts of myricetin with ACR under different ratios and incubation times were analyzed using LC-MS/MS. We also purified and identified the major mono- and di-ACR-myricetin adducts. Furthermore, myricetin could dose-dependently inhibit the formation of ACR in cookies through the formation of mono- and di-ACR adducts.

Ultraprocessed Food Consumption and Risk of Type 2 Diabetes Among Participants of the NutriNet-Santé Prospective Cohort

Importance

Ultraprocessed foods (UPF) are widespread in Western diets. Their consumption has been associated in recent prospective studies with increased risks of all-cause mortality and chronic diseases such as cancer, cardiovascular diseases, hypertension, and dyslipidemia; however, data regarding diabetes are lacking.

Objective

To assess the associations between consumption of UPF and risk of type 2 diabetes (T2D).

Design, Setting, and Participants

In this population-based prospective cohort study, 104 707 participants aged 18 years or older from the French NutriNet-Santé cohort (2009-2019) were included. Dietary intake data were collected using repeated 24-hour dietary records (5.7 per participant on average), designed to register participants' usual consumption for more than 3500 different food items. These were categorized according to their degree of processing by the NOVA classification system.

Main Outcomes and Measures

Associations between UPF consumption and risk of T2D were assessed using cause-specific multivariable Cox proportional hazard models adjusted for known risk factors (sociodemographic, anthropometric, lifestyle, medical history, and nutritional factors).

Results

A total of 104 707 participants (21 800 [20.8%] men and 82 907 [79.2%] women) were included. Mean (SD) baseline age of participants was 42.7 (14.5) years. Absolute T2D rates in the lowest and highest UPF consumers were 113 and 166 per 100 000 person-years, respectively. Consumption of UPF was associated with a higher risk of T2D (multi-adjusted hazard ratio [HR] for an absolute increment of 10 in the percentage of UPF in the diet, 1.15; 95% CI, 1.06-1.25; median follow-up, 6.0 years; 582 252 person-years; 821 incident cases). These results remained statistically significant after adjustment for several markers of the nutritional quality of the diet, for other metabolic comorbidities (HR, 1.13; 95% CI, 1.03-1.23), and for weight change (HR, 1.13; 95% CI, 1.01-1.27). The absolute amount of UPF consumption (grams per day) was consistently associated with T2D risk, even when adjusting for unprocessed or minimally processed food intake (HR for a 100 g/d increase, 1.05; 95% CI, 1.02-1.08).

Conclusions and Relevance

In this large observational prospective study, a higher proportion of UPF in the diet was associated with a higher risk of T2D. Even though these results need to be confirmed in other populations and settings, they provide evidence to support efforts by public health authorities to recommend limiting UPF consumption.

Trial Registration

ClinicalTrials.gov Identifier: NCT03335644.

Translating In Vitro Acrolein-Trapping Capacities of Tea Polyphenol and Soy Genistein to In Vivo Situation is Mediated by the Bioavailability and Biotransformation of Individual Polyphenols

SCOPE

Acrolein (ACR) is a highly toxic unsaturated aldehyde. Humans are both endogenously and exogenously exposed to ACR. Long-term exposure to ACR leads to various chronic diseases. Dietary polyphenols have been reported to be able to attenuate ACR-induced toxicity in vitro via formation of ACR-polyphenol conjugates. However, whether in vitro ACR-trapping abilities of polyphenols can be maintained under in vivo environments is still unknown.

METHODS AND RESULTS

Two most commonly consumed dietary polyphenols, (-)-epigallocatechin-3-gallate (EGCG) from tea and genistein from soy, are evaluated for their anti-Acrolein behaviors both in vitro and in mice. Tea EGCG exerts a much higher capacity to capture ACR than soy genistein in vitro. But translation of in vitro anti-ACR activity into in vivo is mainly mediated by bioavailability and biotransformation of individual polyphenols. It is found that 1) both absorbed EGCG and genistein can trap endogenous ACR by forming mono-ACR adducts and eventually be excreted into mouse urine; 2) both absorbed EGCG and genistein can produce active metabolites, methyl-EGCG (MeEGCG) and orobol, to scavenge endogenous ACR; 3) both MeEGCG and non-absorbed EGCG show ability to trap ACR in the gut; 4) considerable amounts of microbial metabolites of genistein display enhanced anti-ACR capacity both in the body and in the gut, compared to genistein; and 5) biotransformation of genistein is able to boost its in vivo anti-ACR capacity, compared to EGCG.

CONCLUSION

The findings demonstrate that in vivo anti-ACR ability of dietary polyphenols cannot be reflected solely based on their in vitro ability. The bioavailability and biotransformation of individual polyphenols, and especially the gut microbiome, contribute to in vivo anti-ACR ability of dietary polyphenols.

Interaction of volatile organic compounds and underlying liver disease: a new paradigm for risk

Occupational and environmental exposures to industrial chemicals are known to cause hepatotoxicity and liver injury, in humans and in animal models. Historically, research has focused on severe acute liver injury (e.g. fulminant liver failure) or endstage diseases (e.g. cirrhosis and HCC). However, it has become recently recognized that toxicants can cause more subtle changes to the liver. For example, toxicant-associated steatohepatitis, characterized by hepatic steatosis, and inflammation, was recently recognized in an occupational cohort exposed to vinyl chloride. At high occupational levels, toxicants are sufficient to cause liver damage and disease even in healthy subjects with no comorbidities for liver injury. However, it is still largely unknown how exposure to toxicants initiate and possibly more importantly exacerbate liver disease, when combined with other factors, such as underlying non-alcoholic fatty liver disease caused by poor diet and/or obesity. With better understanding of the mechanism(s) and risk factors that mediate the initiation and progression of toxicant-induced liver disease, rational targeted therapy can be developed to better predict risk, as well as to treat or prevent this disease. The purpose of this review is to summarize established and proposed mechanisms of volatile organic compound-induced liver injury and to highlight key signaling events known or hypothesized to mediate these effects.

The mercapturomic profile of health and non-communicable diseases

The mercapturate pathway is a unique metabolic circuitry that detoxifies electrophiles upon adducts formation with glutathione. Since its discovery over a century ago, most of the knowledge on the mercapturate pathway has been provided from biomonitoring studies on environmental exposure to toxicants. However, the mercapturate pathway-related metabolites that is formed in humans—the mercapturomic profile—in health and disease is yet to be established. In this paper, we put forward the hypothesis that these metabolites are key pathophysiologic factors behind the onset and development of non-communicable chronic inflammatory diseases. This review goes from the evidence in the formation of endogenous metabolites undergoing the mercapturate pathway to the methodologies for their assessment and their association with cancer and respiratory, neurologic and cardiometabolic diseases.

Quantitative and Site-Specific Chemoproteomic Profiling of Targets of Acrolein

Acrolein exists in common pollutants, such as cigarette smoke and car exhaust, which has been implicated with many pathological processes. It is also one type of endogenous lipid-derived electrophile (LDE) generated from lipid peroxidation when cells are under oxidative stress. Chemically, acrolein is able to covalently modify nucleophilic residues in proteins so as to influence their structures and functions, and identification of targets of acrolein modification in proteomes is critical for understanding its biological roles. Here, we report a quantitative chemoproteomic method to globally profile acrolein modifications using an aldehyde-directed aniline-based probe. Collectively, we identified >2300 proteins and >500 cysteine sites that are targeted by acrolein. Our data provide valuable information for understanding acrolein-mediated toxicity and expanding our knowledge of oxidative stress-mediated damage and signaling.