Pectin reduces environmental pollutant-induced obesity in mice through regulating gut microbiota: A case study of p,p'-DDE

Polystyrene microplastics aggravate radiation-induced intestinal injury in mice

Radiotherapy is a common treatment for abdominal and pelvic tumors, while the radiation-induced intestinal injury (RIII) is one of the major side-effects of radiotherapy, which reduces the life quality and impedes the treatment completion of cancer patients. Previous studies have demonstrated that environmental pollutant microplastics led to various kinds of injury in the gut, but its effects on RIII are still uncovered. In this study, we fed the C57BL/6J mice with distilled water or 50 μg/d polystyrene microplastics (PSMPs) for 17 days and exposed the mice to total abdominal irradiation (TAI) at day 14. Then the severity of RIII was examined by performing histopathological analysis and microbial community analysis. The results demonstrated that PSMPs significantly aggravated RIII in small intestine rather than colon of mice upon TAI. PSMPs increased levels of the histopathological damage and the microbial community disturbance in mice small intestine, shown by the overabundance of Akkermansiaceae and the decrease of microflora including Lactobacillaceae, Muribaculaceae and Bifidobacteriaceae. In conclusion, our results suggested that more microplastics exposure might led to more severe RIII, which should be considered in patients' daily diet adjustment and clinical radiotherapy plan evaluation. Furthermore, this study also called for the further researches to uncover the underlying mechanism and develop novel strategies to attenuate RIII in mice intestine.

Tomato Pectin Ameliorated Hepatic Steatosis in High-Fat-Diet Mice by Modulating Gut Microbiota and Bile Acid Metabolism

Nonalcoholic fatty liver disease (NAFLD) is a worldwide public health issue. Changes in the gut microbiota structure and composition are closely related to host pathophysiology processes. Pectin is associated with several beneficial health effects. In the present study, we aimed at investigating the effect of tomato pectin (TP) on hepatic steatosis and exploring the underlying mechanisms by focusing on the regulation of the gut microbiota-bile acid axis. Our results showed that TP attenuated high-fat diet (HFD)-induced liver steatosis and inflammation. TP administration increased the diversity of gut microbiota, enhancing the abundance of beneficial bacteria and suppressing the abundance of harmful or conditional pathogenic bacteria. Further antibiotic-caused microbiome depletion confirmed that the anti-NAFLD activities of TP were dependent on the regulation of gut microbiota. Besides, TP intervention affected feces bile acid metabolism and caused significant changes in functional conjugated bile acids, which in turn inhibited the ileum FXR/FGF15 signaling, leading to stimulation of the hepatic bile acid (BA) production. Furthermore, TP treatment accelerated BA excretion, promoted BA transportation, inhibited BA reabsorption, and facilitated cholesterol efflux to relieve HFD-induced hyperlipidemia. These findings provide a potential dietary intervention strategy for TP against NAFLD via modulation of cross-talk between BAs and gut bacteria.

The Need for an Alternative Health Claim Process for Foods Based on Both Nutrient and Contaminant Profiles

Most authorized health claims on foods have been established on the basis of single dietary components, mainly micronutrients, such as vitamins, minerals, and possibly bioactives. Failure to sufficiently define and characterize the nutritional profile of a food product is one of the main reasons for rejection or incomplete status for thousands of health claim applications, whereas the food's contaminant profile is simply not accounted for. The objective of this work was to highlight the accumulating scientific evidence supporting a reform of the health claim evaluation process for foods toward more holistic approaches. This would entail the characterization of multiple nutrient-contaminant pairs and contaminant mixture profiles at contaminant levels currently considered "safe," including their interactions that would impact human health outcome(s) in a net positive or negative direction. The notion of a stable nutritional profile in food commodities has been challenged by studies reporting a variable food contaminant content and a declining content of proteins/micronutrients in crops due to anthropogenic greenhouse gas emissions. A holistic approach in the health claim process for foods would entail the incorporation of cumulative risk assessment and/or risk-benefit protocols that effectively combine health risks and benefits associated with multiple nutritional and contaminant attributes of the food/diet under evaluation.

Intestinal organoids: A thriving and powerful tool for investigating dietary nutrients-intestinal homeostasis axis

Dietary nutrients regulate intestinal homeostasis through a variety of complex mechanisms, to affect the host health. Nowadays, various models have been used to investigate the dietary nutrients-intestinal homeostasis axis. Different from the limited flux in animal experiments, limited intestinal cell types and distorted simulation of intestinal environment of 2D cells, intestinal organoid (IO) is a 3D culture system of mini-gut with various intestinal epithelial cells (IECs) and producibility of intestinal biology. Therefore, IOs is a powerful tool to evaluate dietary nutrients-intestinal homeostasis interaction. This review summarized the application of IOs in the investigation of mechanisms for macronutrients (carbohydrates, proteins and fats) and micronutrients (vitamins and minerals) affecting intestinal homeostasis directly or indirectly (polysaccharides-intestinal bacteria, proteins-amino acids). In addition, new perspectives of IOs in combination with advanced biological techniques and their applications in precise nutrition were proposed.

Perilla, sunflower, and tea seed oils as potential dietary supplements with anti-obesity effects by modulating the gut microbiota composition in mice fed a high-fat diet

PURPOSE

Obesity has become a serious public health problem with its alarmingly increasing prevalence worldwide, prompting researchers to create and develop several anti-obesity drugs. Here, we aimed to investigate the protective effects of perilla seed oil (PSO), sunflower oil (SFO), and tea seed oil (TSO) against obesity through the modulation of the gut microbiota composition and related metabolic changes in mice fed a high-fat diet (HFD).

METHODS

Mice were divided into six equal groups: ND (normal diet); HFD; ORL (HFD supplemented with 20 mg/kg body weight of orlistat); PSO, SFO, and TSO (HFD supplemented with 2 g/kg body weight of PSO, SFO, and TSO, respectively).

RESULTS

Our findings showed that PSO, SFO, and TSO supplementation significantly reduced body weight, organ weight, blood glucose, lipopolysaccharides (LPS), insulin resistance, and improved serum lipid levels (TG, TC, LDL-C, and HDL-C). Meanwhile, the three treatments alleviated oxidative stress and hepatic steatosis and reduced liver lipid accumulation. Relative mRNA expression levels of inflammatory cytokines (TNF-α, IL-1β, IL-6, and MCP-1) and lipid synthesis-related genes (PPAR-γ, FAS, and SREBP-1) were down-regulated, while β-oxidation-related genes (PPAR-α, CPT1a, and CPT1b) were up-regulated in the liver tissue of treated mice. Besides, dietary oil supplementation alleviated HFD-induced gut microbiota dysbiosis by promoting gut microbiota richness and diversity, decreasing the Firmicutes-to-Bacteroidetes ratio, and boosting the abundance of some healthy bacteria, like Akkermansia.

CONCLUSIONS

PSO, SFO, and TSO supplementation could alleviate inflammation, oxidative stress, and hepatic steatosis, likely by modulating the gut microbiota composition in HFD-fed mice.

Structural characteristics of mixed pectin from ginseng berry and its anti-obesity effects by regulating the intestinal flora

Ginseng berry is the mature berry of ginseng and its polysaccharide has hypolipidaemic effect, but its mechanism remains unclear. A pectin (GBPA) with a molecular weight of 3.53 × 10⁴ Da was isolated from ginseng berry, it was mainly composed of Rha (25.54 %), GalA (34.21 %), Gal (14.09 %) and Ara (16.25 %). Structural analysis showed that GBPA is a mixed pectin containing rhamnogalacturonan-I and homogalacturonan domains and has a triple helix structure. GBPA distinctly improved lipid disorders in obese rats, and changed intestinal flora with enrichments of Akkermansia, Bifidobacterium, Bacteroides and Prevotella, improved the levels of acetic acid, propionic acid, butyric acid and valeric acid. Serum metabolites which involved in the lipid regulation-related pathway, including cinnzeylanine, 10-Hydroxy-8-nor-2-fenchanone glucoside, armillaribin, 24-Propylcholestan-3-ol, were also greatly changed after GBPA treatment. GBPA activated AMP-activated protein kinase, phosphorylated acetyl-CoA carboxylase, and reduced the expression of lipid synthesis-related genes sterol regulatory element-binding protein-1c and fatty acid synthases. The regulatory effects of GBPA on lipid disorders in obese rats are related to the regulation of intestinal flora and activation of AMP-activated protein kinase pathway. Ginseng berry pectin could be considered in the future as a health food or medicine to prevent obesity.

Rhamnogalacturonan-I enriched pectin from steamed ginseng ameliorates lipid metabolism in type 2 diabetic rats via gut microbiota and AMPK pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng C. A. Meyer (Ginseng) has traditionally been used to treat diabetes. Polysaccharide is the main active component of ginseng, and has been proved to have hypoglycaemic and hypolipidaemic effects, but its mechanism remains unclear.

AIM OF THE STUDY

This study aimed to evaluate the effect and the potential mechanism of rhamnogalacturonan-I enriched pectin (GPS-1) from steamed ginseng on lipid metabolism in type 2 diabetes mellitus (T2DM) rats.

MATERIALS AND METHODS

GPS-1 was prepared by water extraction, ion-exchange and gel chromatography. High-glucose/high-fat diet combined with streptozotocin was used to establish T2DM rat models, and lipid levels in serum and liver were tested. 16S rRNA sequencing and gas chromatography-mass spectrometry were used to detect the changes of gut microbiota and metabolites. The protein and mRNA levels of lipid synthesis-related genes were detected by Western blot and quantitative real-time polymerase chain reaction.

RESULTS

The polyphagia, polydipsia, weight loss, hyperglycaemia, hyperlipidaemia and hepatic lipid accumulation in T2DM rats were alleviated after GPS-1 intervention. GPS-1 modulated the gut microbiota composition of T2DM rats, increased the levels of short-chain fatty acids, and promoted the secretion of glucagon-like peptide-1 and peptide tyrosine tyrosine. Further, GPS-1 activated AMP-activated protein kinases, phosphorylated acetyl-CoA carboxylase, reduced the expression of sterol regulatory element-binding protein-1c and fatty acid synthases in T2DM rats.

CONCLUSIONS

The regulation effects of GPS-1 on lipid metabolism in T2DM rats are related to the regulation of gut microbiota and activation of AMP-activated protein kinase pathway.

Metallothionein gene expression in rat tissues: response to dietary restriction after orally dichlorodiphenyldichloroethylene (DDE) exposure and high-fat feeding

Dichlorodiphenyldichloroethylene (DDE) is an environmental pollutant that accumulates in adipose tissue through the food chain. Hypercaloric, high-fat diet is considered to promote the accumulation of toxic lipophilic substances in tissues, whereas the loss of body fat through caloric restriction results in a recirculation of these substances. In rats, oral administration of DDE causes the onset of tissues damage; the concomitant intake of a high-fat diet ameliorates tissues status, probably because of the entrapment of the lipophilic substance in fat depots. Recent evidence demonstrates that DDE alters the expression of metallothioneins, proteins involved in cellular defense from oxidative stress, in a diet- and tissue-specific manner. This study is aimed to verify if 2 weeks of caloric restriction after the oral DDE treatment can modify metallothionein gene expression in tissues of high-fat fed rats. Real-time PCR analysis demonstrates that metallothionein gene expression after calorie restriction is tissue-specific and strongly influenced by both previous dietary conditions and DDE exposure. To avoid misleading conclusions on the interference of toxic xenobiotics on metallothionein gene expression is particularly important to consider the tissue, the cellular conditions, and the nutritional status of the animals, especially when the protein is used as an index of cells health.

Current Research on the Effects of Non-Digestible Carbohydrates on Metabolic Disease

Metabolic diseases (MDs), including cardiovascular diseases (CVDs) and diabetes, occur when the body’s normal metabolic processes are disrupted. Behavioral risk factors such as obesity, physical inactivity, and dietary habits are strongly associated with a higher risk of MD. However, scientific evidence strongly suggests that balanced, healthy diets containing non-digestible carbohydrates (NDCs), such as dietary fiber and resistant starch, can reduce the risk of developing MD. In particular, major properties of NDCs, such as water retention, fecal bulking, viscosity, and fermentation in the gut, have been found to be important for reducing the risk of MD by decreasing blood glucose and lipid levels, increasing satiety and insulin sensitivity, and modifying the gut microbiome. Short chain fatty acids produced during the fermentation of NDCs in the gut are mainly responsible for improvement in MD. However, the effects of NDCs are dependent on the type, source, dose, and duration of NDC intake, and some of the mechanisms underlying the efficacy of NDCs on MD remain unclear. In this review, we briefly summarize current studies on the effects of NDCs on MD and discuss potential mechanisms that might contribute to further understanding these effects.

The regulatory roles of dietary fibers on host health via gut microbiota-derived short chain fatty acids

As a component of nutraceuticals, dietary fibers (DFs) are essential for maintain human growth and health via the regulation of gut microbiota in the digestive tract. In this review, we summarize food-derived DFs and their effect on gut microbiota-derived short-chain fatty acids (SCFAs). DFs accelerate the production of SCFAs mainly by stimulating intestinal Lactobacillus, Bifidobacterium and Akkermansia to treat diabetes, obesity, cancer, inflammation and immunodeficiency. Further studies should focus on clarifying the detailed mechanism between DFs and diseases associated with gut microbiota-mediated SCFAs.

Recent advances in utilization of pectins in biomedical applications: a review focusing on molecular structure-directing health-promoting properties

The numerous health benefits of pectins justify their inclusion in human diets and biomedical products. This review provides an overview of pectin extraction and modification methods, their physico-chemical characteristics, health-promoting properties, and pharmaceutical/biomedical applications. Pectins, as readily available and versatile biomolecules, can be tailored to possess specific functionalities for food, pharmaceutical and biomedical applications, through judicious selection of appropriate extraction and modification technologies/processes based on green chemistry principles. Pectin's structural and physicochemical characteristics dictate their effects on digestion and bioavailability of nutrients, as well as health-promoting properties including anticancer, immunomodulatory, anti-inflammatory, intestinal microflora-regulating, immune barrier-strengthening, hypercholesterolemia-/arteriosclerosis-preventing, anti-diabetic, anti-obesity, antitussive, analgesic, anticoagulant, and wound healing effects. HG, RG-I, RG-II, molecular weight, side chain pattern, and degrees of methylation, acetylation, amidation and branching are critical structural elements responsible for optimizing these health benefits. The physicochemical characteristics, health functionalities, biocompatibility and biodegradability of pectins enable the construction of pectin-based composites with distinct properties for targeted applications in bioactive/drug delivery, edible films/coatings, nano-/micro-encapsulation, wound dressings and biological tissue engineering. Achieving beneficial synergies among the green extraction and modification processes during pectin production, and between pectin and other composite components in biomedical products, should be key foci for future research.

Effect of soybean insoluble dietary fiber on prevention of obesity in high-fat diet fed mice via regulation of the gut microbiota

Increasing evidence has shown that the gut microbiota plays an important role in preventing obesity; however, the mechanism by which insoluble dietary fiber (IDF) prevents high-fat diet (HFD)-induced obesity remains unclear. This study aimed to investigate the effect of SIDF on obesity in HFD mice and determine the mechanism by which it prevents obesity through regulating the gut microbiota. Soybean insoluble dietary fiber (SIDF) was used as an intervention in HFD mice for 20 weeks. The results showed that SIDF significantly reduced the body weight (BW), fat index, total cholesterol, triglyceride, and low-density lipoprotein cholesterol while increasing the content of high-density lipoprotein cholesterol in HFD mice. SIDF intervention was also beneficial for the reduction of liver lipid content and fatty droplets in mice. Furthermore, SIDF intervention improved the gut microbiota composition by increasing the relative abundance of potentially beneficial bacteria (such as Lactobacillales [order], Lactobacillus [genus], Lachnospirace_Nk4A136_group [genus]), and reduced the relative abundance of potentially harmful bacteria (such as Lachnospiraceae [family] and Bacteroides_acidifaciens [species]), which correlated with obesity (at least p < 0.05 in all instances). Finally, SIDF was fermented by related beneficial bacteria, which increased the content of the short-chain fatty acids (SCFAs), and promoted the secretion of satiety hormones. In conclusion, SIDF intervention could prevent obesity in HFD mice by modulating the gut microbiota composition. Hence, SIDF may be used as a potential ingredient in functional foods.

The Impact of Environmental Chemicals on the Gut Microbiome

Since the surge of microbiome research in the last decade, many studies have provided insight into the causes and consequences of changes in the gut microbiota. Among the multiple factors involved in regulating the microbiome, exogenous factors such as diet and environmental chemicals have been shown to alter the gut microbiome significantly. Although diet substantially contributes to changes in the gut microbiome, environmental chemicals are major contaminants in our food and are often overlooked. Herein, we summarize the current knowledge on major classes of environmental chemicals (bisphenols, phthalates, persistent organic pollutants, heavy metals, and pesticides) and their impact on the gut microbiome, which includes alterations in microbial composition, gene expression, function, and health effects in the host. We then discuss health-related implications of gut microbial changes, which include changes in metabolism, immunity, and neurological function.

Toxicology and Microbiota: How Do Pesticides Influence Gut Microbiota? A Review

In recent years, new targets have been included between the health outcomes induced by pesticide exposure. The gastrointestinal tract is a key physical and biological barrier and it represents a primary site of exposure to toxic agents. Recently, the intestinal microbiota has emerged as a notable factor regulating pesticides’ toxicity. However, the specific mechanisms related to this interaction are not well known. In this review, we discuss the influence of pesticide exposure on the gut microbiota, discussing the factors influencing gut microbial diversity, and we summarize the updated literature. In conclusion, more studies are needed to clarify the host–microbial relationship concerning pesticide exposure and to define new prevention interventions, such as the identification of biomarkers of mucosal barrier function.

Chronic oral exposure to pesticides and their consequences on metabolic regulation: role of the microbiota

Pesticides have long been used in agriculture and household treatments. Pesticide residues can be found in biological samples for both the agriculture workers through direct exposure but also to the general population by indirect exposure. There is also evidence of pesticide contamination in utero and trans-generational impacts. Whilst acute exposure to pesticides has long been associated with endocrine perturbations, chronic exposure with low doses also increases the prevalence of metabolic disorders such as obesity or type 2 diabetes. Dysmetabolism is a low-grade inflammation disorder and as such the microbiota plays a role in its etiology. It is therefore important to fully understand the role of microbiota on the genesis of subsequent health effects. The digestive tract and mostly microbiota are the first organs of contact after oral exposure. The objective of this review is thus to better understand mechanisms that link pesticide exposure, dysmetabolism and microbiota. One of the key outcomes on the microbiota is the reduced Bacteroidetes and increased Firmicutes phyla, reflecting both pesticide exposure and risk factors of dysmetabolism. Other bacterial genders and metabolic activities are also involved. As for most pathologies impacting microbiota (including inflammatory disorders), the role of prebiotics can be suggested as a prevention strategy and some preliminary evidence reinforces this axis.

Effects of endocrine disrupting chemicals in host health: Three-way interactions between environmental exposure, host phenotypic responses, and gut microbiota

Endocrine disrupting chemicals (EDCs) have gradually become a global health hazard in recent decades. Gut microbiota (GM) provides a crucial interface between the environment and the human body. A triad relationship may exist between EDCs exposure, host phenotypic background, and GM effects. In this review, we attempted to parse out the contribution of GM on the alteration of host phenotypic responses induced by EDCs, suggesting that GM intervention may be used as a therapeutic strategy to limit the expansion of pathogen. These studies can increase the understanding of pathogenic mechanisms, and help to identify the modifiable environmental factors and microbiota characteristics in people with underlying disease susceptibility for prevention and remediation.

Okra pectin relieves inflammatory response and protects damaged intestinal barrier in caerulein-induced acute pancreatic model

BACKGROUND

Protecting the intestinal mucosa from being destroyed helps reduce the inflammation caused by acute pancreatitis (AP). In this study, whether okra pectin (OP) could attenuate the inflammation of AP through protecting the intestinal barrier was investigated.

RESULTS

OP was obtained from crude okra pectin (COP) through the purification by DEAE cellulose 52 column. Supplementation with OP or COP in advance reduced the severity of AP, as revealed by lower serum amylase and lipase levels, abated pancreatic edema, attenuated myeloperoxidase activity and pancreas histology. OP or COP inhibited the production of pancreatic proinflammatory cytokines, including tumor necrosis factor-α and interleukin-6. In addition, the upregulation of AP-related proteins including ZO-1, occludin, the antibacterial peptide-defensin-1 (DEFB1) and cathelicidin-related antimicrobial peptide (CRAMP), as well as the histological examination of colon injuries, demonstrated that OP or COP provision could effectively maintain intestinal barrier function. Ultimately, dietary OP or COP supplementation could inhibit AP-induced intestinal inflammation. For the above, the effect of OP was better than COP.

CONCLUSION

Dietary OP supplementation could be considered as a preventive method that effectively interferes with intestinal damage and attenuates inflammatory responses trigged by AP. © 2020 Society of Chemical Industry.

Prevention of loperamide induced constipation in mice by KGM and the mechanisms of different gastrointestinal tract microbiota regulation

Constipation is one of the most prevalent gastrointestinal tract diseases. Konjac glucomannan (KGM) dietotherapy can effectively relieve the clinical symptoms of patients with constipation. However, the causal relationship among KGM, constipation and different gastrointestinal microbiome (i.e., the stomach {St}, small intestine {S}, and large intestine {L}) remains poorly understood. In this study, constipated mice were treated with KGM (75, 150, 300 mg/kg bw). Results showed that KGM treatment improved the general physiological state, fecal character, small intestinal propulsive rate, gastric emptying rate, MTL and AchE activities, ET-1, 5-HT, and NO levels, and SCFA concentrations. KGM in the diets of constipated mice reduced the diversity of St and S microbiota, while increased those in the L. The KGM intervention regulated the microbiota profile, which afterwards was closer to the normal mouse group: confirmation was provided by different changes of bacteria like Lactobacillus, Bifidobacterium and Allobaculum spp et al.

Gut microbiome alterations induced by tributyltin exposure are associated with increased body weight, impaired glucose and insulin homeostasis and endocrine disruption in mice

Tributyltin (TBT), an organotin compound once widely used in agriculture and industry, has been reported to induce obesity and endocrine disruption. Gut microbiota has a strong connection with the host's physiology. Nevertheless, the influences of TBT exposure on gut microbiota and whether TBT-influenced gut microbiota is related to TBT-induced toxicity remain unclear. To fill these gaps, ICR (CD-1) mice were respectively exposed to TBT at NOEL (L-TBT) and tenfold NOEL (H-TBT) daily by gavage for 8 weeks in the current study. The results showed that TBT exposure significantly increased body weight as well as epididymal fat, and led to adipocyte hypertrophy, dyslipidemia and impaired glucose and insulin homeostasis in mice. Additionally, TBT exposure significantly decreased the levels of T4, T3 and testosterone in serum. Also of note, TBT exposure changed gut microbiota composition mainly by decreasing Bacteroidetes and increasing Firmicutes proportions. To confirm the role of gut microbiota in TBT-induced overweight and hormonal disorders, fecal microbiota transplantation was performed and the mice receiving gut microbiota from H-TBT mice had similar phenotypes with their donor mice including significant body weight and epididymal fat gain, glucose and insulin dysbiosis and hormonal disorders. These results suggested that gut microbiome altered by TBT exposure was involved in the TBT-induced increased body weight, impaired glucose and insulin homeostasis and endocrine disruption in mice, providing significant evidence and a novel perspective for better understanding the mechanism by which TBT induces toxicity.

Potential therapeutic applications of the gut microbiome in obesity: from brain function to body detoxification

The prevalence of obesity is rising every year and associated comorbidities such as cardiovascular diseases are among the leading causes of death worldwide. The gut microbiota has recently emerged as a potential target for therapeutic applications to prevent and treat those comorbidities. In this review, we focus on three conditions related to obesity in which the use of gut microbiota modulators could have benefits; mood disorders, eating behaviors, and body detoxification of persistent organic pollutants (POPs). On one hand, modulation of gut-derived signals to the brain in a context of obesity is involved in the development of neuroinflammation and can subsequently alter behaviors. An altered gut microbiome could change these signals and alleviate their consequences. On the other hand, obesity is associated with an increased accumulation of lipophilic contaminants, such as POPs. Targeting the microbiota could help body detoxication by reducing bioavailability, enhancing degradation by bioremediation or their excretion through the enterohepatic circulation. Thus, a supplementation of prebiotics, probiotics, or synbiotics could represent a complementary strategy to current ones, such as medication and lifestyle modifications, to decrease depression, alter eating behaviors, and lower body burden of pollutants considering the actual obesity epidemic our society is facing.

Perinatal exposure to 2-Ethylhexyl Diphenyl Phosphate (EHDPHP) affected the metabolic homeostasis of male mouse offspring: Unexpected findings help to explain dose- and diet- specific phenomena

The environmental health risks of a new type of organophosphate flame retardant, 2-ethylhexyl diphenyl phosphate (EHDPHP), which is present in large quantities in various Nordic foods, have attracted the attention of scientists recently. In this study, the metabolic homeostasis of low-fat diet (LFD) and high-fat diet (HFD) fed male mice offspring was assessed after perinatal exposure to two doses (30 μg/kg bw/day and 300 μg/kg bw/day) of EHDPHP. Perinatal exposure to EHDPHP resulted in weight changes in male mice offspring, altered glucose tolerance and induced liver damage, and surprisingly these changes were dose- and diet- specific. Then the ¹H NMR-based metabolomics, 16S rRNA sequencing, and qRT-PCR techniques were used to explore the mechanisms of these specific changes. The results indicate that the increase in short-chain fatty acids and the increase in Clostridium in the high-dose group may be responsible for the dose-specificity, while the attenuation of the purine metabolic pathway and the decrease in glutamine levels in the HFD group are accountable for the diet-specificity. In addition, down-regulation of PPARG (peroxisome proliferator-activated receptor gamma) gene expression levels might have caused the decrease in body weight in the H + HFD (high dose exposure with HFD feeding) group. Over all, these results elucidated the effects of dosage and diet on the toxicology of EHDPHP.