Nutrient-induced inflammation in the intestine

Gut microbiota and associated metabolites: key players in high-fat diet-induced chronic diseases

Excessive intake of dietary fats is strongly associated with an increased risk of various chronic diseases, such as obesity, diabetes, hepatic metabolic disorders, cardiovascular disease, chronic intestinal inflammation, and certain cancers. A significant portion of the adverse effects of high-fat diet on disease risk is mediated through modifications in the gut microbiota. Specifically, high-fat diets are linked to reduced microbial diversity, an overgrowth of gram-negative bacteria, an elevated Firmicutes-to-Bacteroidetes ratio, and alterations at various taxonomic levels. These microbial alterations influence the intestinal metabolism of small molecules, which subsequently increases intestinal permeability, exacerbates inflammatory responses, disrupts metabolic functions, and impairs signal transduction pathways in the host. Consequently, diet-induced changes in the gut microbiota play a crucial role in the initiation and progression of chronic diseases. This review explores the relationship between high-fat diets and gut microbiota, highlighting their roles and underlying mechanisms in the development of chronic metabolic diseases. Additionally, we propose probiotic interventions may serve as a promising adjunctive therapy to counteract the negative effects of high-fat diet-induced alterations in gut microbiota composition.

Microbe-dependent and independent effects of diet on metabolic inflammation in glucose metabolism regulation

Diet can contribute to the development of metabolic disease including type 2 diabetes (T2D) by inducing metabolic inflammation. While the gut microbiota mediates the effects of diet, the diet can also exert its effects independent of gut microbes. The microbe-dependent and -independent effects of diet on inflammation remain to be elucidated. This review examines recent advances and dissects the specifics of both gut microbe-dependent and independent mechanisms through which diet impacts inflammation and glucose metabolism. We delineate how diet interacts with the gut microbiome and induces metabolic inflammation. We also describe the direct effects of dietary components and their related metabolites on the immune system, and explore how diet-induced sterile inflammation may contribute to metabolic disorders. It is important to consider both microbe-dependent and independent pathways when developing therapeutic approaches aimed at preventing T2D.

The link between ultra-processed food consumption, fecal microbiota, and metabolomic profiles in older mediterranean adults at high cardiovascular risk

BACKGROUND

Ultra-processed food (UPF) consumption has been linked to adverse metabolic outcomes, potentially mediated by alterations in gut microbiota and metabolite production.

OBJECTIVE

This study aims to explore the cross-sectional and longitudinal associations between NOVA-classified UPF consumption, fecal microbiota, and fecal metabolome in a population of Mediterranean older adults at high cardiovascular risk.

METHODS

A total of 385 individuals, aged between 55 and 75 years, were included in the study. Dietary and lifestyle information, anthropometric measurements, and stool samples were collected at baseline and after 1-year follow-up. Fecal microbiota and metabolome were assessed using 16 S rRNA sequencing and liquid chromatography-tandem mass spectrometry, respectively.

RESULTS

At baseline, higher UPF consumption was associated with lower abundance of Ruminococcaceae incertae sedis (β = - 0.275, P = 0.047) and lower concentrations of the metabolites propionylcarnitine (β = - 0.0003, P = 0.013) and pipecolic acid (β = - 0.0003, P = 0.040) in feces. Longitudinally, increased UPF consumption was linked to reduced abundance of Parabacteroides spp. after a 1-year follow-up (β = - 0.278, P = 0.002).

CONCLUSIONS

High UPF consumption was associated with less favorable gut microbiota and metabolite profiles, suggesting a possible link to reduced short-chain fatty acid (SCFA) production, altered mitochondrial energy metabolism, and impaired amino acid metabolism. These findings support the reduction of UPF consumption and the promotion of dietary patterns rich in fiber for better gut health. Further research is needed to confirm these associations and clarify the underlying mechanisms.

TRIAL REGISTRATION

ISRCTN89898870 ( https://doi.org/10.1186/ISRCTN89898870 ).

Identification of Diagnostic Biomarkers for Colorectal Polyps Based on Noninvasive Urinary Metabolite Screening and Construction of a Nomogram

PURPOSE/BACKGROUNDS

Colorectal polyps (CRPs) are precursors to colorectal cancer (CRC), and early detection is crucial for prevention. Traditional diagnostic methods are invasive, prompting a need for noninvasive biomarkers. This study aimed to identify urinary metabolite biomarkers for diagnosing CRPs and construct a diagnostic nomogram based on noninvasive urinary metabolite screening.

PATIENTS AND METHODS

A total of 192 participants, including 64 CRP patients and 128 healthy controls, were recruited. Urine samples were analyzed using untargeted gas chromatography-mass spectrometry (GC-MS) and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). Metabolite screening was performed using weighted gene coexpression network analysis (WGCNA), least absolute shrinkage and selection operator (LASSO), and support vector machine-recursive feature elimination (SVM-RFE). A diagnostic nomogram was developed based on identified metabolites, and its performance was evaluated using receiver operating characteristic (ROC) curves, calibration plots, and decision curve analysis (DCA).

RESULTS

A total of 350 metabolites were identified, with 7 key metabolites significantly associated with CRP. Multivariate logistic regression analysis identified Saccharin (OR = 48.3, 95% CI: 4.44-525.32) and N-omega-acetylhistamine (OR = 27.91, 95% CI: 2.31-337.06) as significant risk factors for CRP, while N-methyl-L-proline, trimethylsilyl ester (OR = 0.08, 95% CI: 0.01-0.8) was a protective factor. A nomogram incorporating these metabolites demonstrated strong discriminatory power, with AUC values of 0.974 and 0.960 in the training and validation sets, respectively. Calibration plots and DCA confirmed the model's accuracy and clinical utility.

CONCLUSIONS

This study successfully identified seven urinary metabolites as potential noninvasive biomarkers for CRP. The constructed diagnostic nomogram, based on these metabolites, offers high predictive accuracy and clinical applicability, providing a promising tool for the early detection of CRP.

Overview of the compromised mucosal integrity in celiac disease

Intestinal epithelium is a dynamic cellular layer that lines the small-bowel and makes a relatively impenetrable barrier to macromolecules. Intestinal epithelial cell polarity is crucial in coordinating signalling pathways within cells and mainly regulated by three conserved polarity protein complexes, the Crumbs (Crb) complex, partitioning defective (PAR) complex, and Scribble (Scrib) complex. Polarity proteins regulate the proper establishment of the intercellular junctional complexes including tight junctions (TJs), adherence junctions (AJs), and desmosomes which hold epithelial cells together and play a major role in maintaining intestinal barrier integrity. Impaired intestinal epithelial cell polarity and barrier integrity result in irreversible immune responses, the host- microbial imbalance and intestinal inflammatory disorders. Disassembling the epithelial tight junction and augmented paracellular permeability is a conspicuous hallmark of celiac disease (CD) pathogenesis. There are several dietary components that can improve intestinal integrity and function. The aim of this review article is to summarize current information about the association of polarity proteins and AJC damages with pathogenesis of CD.

Gut microbiota in obesity and related complications: Unveiling the complex interplay

In recent years, the obesity epidemic has escalated into a serious public health catastrophe that is only getting worse. However, research into the pathophysiological pathways behind the obesity development and the illnesses that it is associated with is ongoing. In the last decades, it is now clear that the gut microbiota plays a significant role in the genesis and progression of obesity and obesity-related illnesses, particularly changes in its metabolites and composition as obesity progresses. Here, we provide a summary of the processes by which variations in gut metabolite levels and the composition of gut microbiota affect obesity and associated disorders. The bacteria residing in the gut release several chemicals that influence the appetite control, metabolism, and other systems. Since it can either encourage or restrict the deposition of fat in several different ways, the gut microbiota's role in obesity is debatable. Additionally, we go over potential therapeutic approaches that could be utilized to alter gut microbiota composition and focus on the important metabolic pathways associated with obesity and metabolic disorders linked to obesity.

Male infertility risk and gut microbiota: a Mendelian randomization study

Background

In recent decades, the decline of male sperm quality has become a worldwide phenomenon, with sperm quality of critical importance for the ability to conceive naturally. Recent studies suggest that male fertility function is closely linked to the gut microbiota, however, the cause-and-effect association between the gut microbiota and male infertility risk is currently unclear.

Methods

We performed one two-sample Mendelian randomization (MR) study, which uses summary data on human gut microbiota from the MiBioGen consortium as factors of exposure. FinnGen Consortium R8 data was used to obtain GWAS data for male infertility. To evaluate cause-and-effect associations linking gut microbiota and male infertility risk with multiple Mendelian randomization methods, we included inverse variance weighted (IVW), MR-Egger, and Maximum Likelihood (ML) Ratio. The heterogeneity of instrumental variables was evaluated through Cochran's Q, Rucker's Q, and leave-one-out analysis methods.

Results

We found a positive association between Allisonella, Anaerotruncus, Barnesiella, Intestinibacter, and Lactococcus with male infertility risk according to the MR analysis results. Bacteroides Romboutsia, Ruminococcaceae (NK4A2140group), and Ruminococcaceae (UCG011) play a protective function in male infertility pathogenesis.

Conclusion

It was found that gut microbiota and infertility are causally related in this study. In subsequent studies, there is a need to build a larger and more comprehensive GWAS database on male infertility, which will reveal the underlying mechanisms for gut microbiota and male infertility. There is a need for randomized controlled trials for validating the protective effect of the associated gut microbiota against male infertility risk, and for exploring the associated mechanisms.

The Role of Lipids in the Regulation of Immune Responses

Lipid metabolism plays a major role in the regulation of the immune system. Exogenous (dietary and microbial-derived) and endogenous (non-microbial-derived) lipids play a direct role in regulating immune cell activation, differentiation and expansion, and inflammatory phenotypes. Understanding the complexities of lipid-immune interactions may have important implications for human health, as certain lipids or immune pathways may be beneficial in circumstances of acute infection yet detrimental in chronic inflammatory diseases. Further, there are key differences in the lipid effects between specific immune cell types and location (e.g., gut mucosal vs. systemic immune cells), suggesting that the immunomodulatory properties of lipids may be tissue-compartment-specific, although the direct effect of dietary lipids on the mucosal immune system warrants further investigation. Importantly, there is recent evidence to suggest that lipid-immune interactions are dependent on sex, metabolic status, and the gut microbiome in preclinical models. While the lipid-immune relationship has not been adequately established in/translated to humans, research is warranted to evaluate the differences in lipid-immune interactions across individuals and whether the optimization of lipid-immune interactions requires precision nutrition approaches to mitigate or manage disease. In this review, we discuss the mechanisms by which lipids regulate immune responses and the influence of dietary lipids on these processes, highlighting compelling areas for future research.

Healthy Diet and Lifestyle Improve the Gut Microbiota and Help Combat Fungal Infection

Western diets are rapidly spreading due to globalization, causing an increase in obesity and diseases of civilization. These Western diets are associated with changes in the gut microbiota related to intestinal inflammation. This review discusses the adverse effects of Western diets, which are high in fat and sugar and low in vegetable fiber, on the gut microbiota. This leads to gut dysbiosis and overgrowth of Candida albicans, which is a major cause of fungal infection worldwide. In addition to an unhealthy Western diet, other factors related to disease development and gut dysbiosis include smoking, excessive alcohol consumption, lack of physical activity, prolonged use of antibiotics, and chronic psychological stress. This review suggests that a diversified diet containing vegetable fiber, omega-3 polyunsaturated fatty acids, vitamins D and E, as well as micronutrients associated with probiotic or prebiotic supplements can improve the biodiversity of the microbiota, lead to short-chain fatty acid production, and reduce the abundance of fungal species in the gut. The review also discusses a variety of foods and plants that are effective against fungal overgrowth and gut dysbiosis in traditional medicine. Overall, healthy diets and lifestyle factors contribute to human well-being and increase the biodiversity of the gut microbiota, which positively modulates the brain and central nervous system.

New insights into the role of dietary triglyceride absorption in obesity and metabolic diseases

The incidence of obesity and associated metabolic diseases is increasing globally, adversely affecting human health. Dietary fats, especially triglycerides, are an important source of energy for the body, and the intestine absorbs lipids through a series of orderly and complex steps. A long-term high-fat diet leads to intestinal dysfunction, inducing obesity and metabolic disorders. Therefore, regulating dietary triglycerides absorption is a promising therapeutic strategy. In this review, we will discuss diverse aspects of the dietary triglycerides hydrolysis, fatty acid uptake, triglycerides resynthesis, chylomicron assembly, trafficking, and secretion processes in intestinal epithelial cells, as well as potential targets in this process that may influence dietary fat-induced obesity and metabolic diseases. We also mention the possible shortcomings and deficiencies in modulating dietary lipid absorption targets to provide a better understanding of their administrability as drugs in obesity and related metabolic disorders.

Why are western diet and western lifestyle pro-inflammatory risk factors of celiac disease?

The prevalence of celiac disease increased in recent years. In addition to the genetic and immunological factors, it appears that environmental determinants are also involved in the pathophysiology of celiac disease. Gastrointestinal infections impact the development of celiac disease. Current research does not directly confirm the protective effect of natural childbirth and breastfeeding on celiac disease. However, it seems that in genetically predisposed children, the amount of gluten introduced into the diet may have an impact on celiac disease development. Also western lifestyle, including western dietary patterns high in fat, sugar, and gliadin, potentially may increase the risk of celiac disease due to changes in intestinal microbiota, intestinal permeability, or mucosal inflammation. Further research is needed to expand the knowledge of the relationship between environmental factors and the development of celiac disease to define evidence-based preventive interventions against the development of celiac disease. The manuscript summarizes current knowledge on factors predisposing to the development of celiac disease including factors associated with the western lifestyle.

Functional fiber enhances the effect of every-other-day fasting on insulin sensitivity by regulating the gut microecosystem

Every-other-day fasting (EODF), which involves alternating days of fasting and feeding, has been reported to lower obesity, and dietary fibers can improve metabolism by altering gut microbiota. This study investigated whether the combination of functional fiber (FF) and EODF (FF-EODF) can further improve insulin sensitivity by regulating the composition of microbiota and curbing weight gain. Twenty-eight diet-induced obese (DIO) mice were randomly divided into four experimental groups (n=7): (1) ad-libitum (AL), (2) EODF, (3) 4% FF-EODF and (4) 6% FF-EODF. After exposure to a high-fat basal diet (HFD) for 12 weeks (1-12 weeks, period 1) and then to a normal chow diet (NCD) for 4 weeks (13-16 weeks, period 2). Compared with EODF alone, 6% FF-EODF treatment could significantly improve the insulin sensitivity of DIO mice without affecting their body weight during period 1(HFD), while significantly increasing satiety, energy consumption, weight, and adipose loss, and insulin sensitivity during period 2 (NCD). Meanwhile, FF-EODF showed a higher increase in short-chain fatty acids (SCFAs) and restored the proportion of induced intraepithelial lymphocytes in the intestinal epithelium compared to EODF alone. Although EODF could increase the relative abundances of Lactobacillus and Bifidobacteriumin, FF supplementation further increased the relative abundance of Lactobacillus, Bifidobacterium, and S24-7 in the intestine. This increase was positively correlated with the decrease in adiposity and insulin resistance, indicating that FF plays a key role in insulin improvement. Our study demonstrated the potential of FF-EODF in promoting insulin sensitivity and reducing body weight via beneficial regulation of gut microecosystem.

Diet-related changes of basal lamina fenestrations in the villous epithelium of the rat small intestine: Statistical analysis on scanning electron microscopy

The epithelial basal lamina of the small intestine has numerous fenestrations for intraepithelial migration of leukocytes. We have reported dynamic changes of fenestrations in dietary conditions. To investigate this phenomenon, we performed statistical analyses using scanning electron microscopy images of the epithelial basal lamina of rat intestinal villi after removal of the villous epithelium by osmium maceration. We examined structural changes in the number and size of fenestrations in the rat jejunum and ileum under fasted and fed states for 24 h. Our findings revealed that, in the jejunum, the number of free cells migrating into the epithelium through fenestrations increased from 2 h after feeding, resulting in an increase in the fenestration size of intestinal villi; the number of free cells then tended to decrease at 6 h after feeding, and the fenestration size also gradually decreased. By contrast, the increase in the fenestration size by feeding was not statistically significant in the ileum. These findings indicate that the number of migrating cells increases in the upper part of the small intestine under dietary conditions, which may influence the absorption efficiency of nutrients including lipids, as well as the induction of nutrient-induced inflammation.

High-Fat, Western-Style Diet, Systemic Inflammation, and Gut Microbiota: A Narrative Review

The gut microbiota is responsible for recovering energy from food, providing hosts with vitamins, and providing a barrier function against exogenous pathogens. In addition, it is involved in maintaining the integrity of the intestinal epithelial barrier, crucial for the functional maturation of the gut immune system. The Western diet (WD)—an unhealthy diet with high consumption of fats—can be broadly characterized by overeating, frequent snacking, and a prolonged postprandial state. The term WD is commonly known and intuitively understood. However, the strict digital expression of nutrient ratios is not precisely defined. Based on the US data for 1908–1989, the calory intake available from fats increased from 32% to 45%. Besides the metabolic aspects (hyperinsulinemia, insulin resistance, dyslipidemia, sympathetic nervous system and renin-angiotensin system overstimulation, and oxidative stress), the consequences of excessive fat consumption (high-fat diet—HFD) comprise dysbiosis, gut barrier dysfunction, increased intestinal permeability, and leakage of toxic bacterial metabolites into the circulation. These can strongly contribute to the development of low-grade systemic inflammation. This narrative review highlights the most important recent advances linking HFD-driven dysbiosis and HFD-related inflammation, presents the pathomechanisms for these phenomena, and examines the possible causative relationship between pro-inflammatory status and gut microbiota changes.

Mesenteric lymphatic dysfunction promotes insulin resistance and represents a potential treatment target in obesity

Visceral adipose tissue (VAT) encases mesenteric lymphatic vessels and lymph nodes through which lymph is transported from the intestine and mesentery. Whether mesenteric lymphatics contribute to adipose tissue inflammation and metabolism and insulin resistance is unclear. Here we show that obesity is associated with profound and progressive dysfunction of the mesenteric lymphatic system in mice and humans. We find that lymph from mice and humans consuming a high-fat diet (HFD) stimulates lymphatic vessel growth, leading to the formation of highly branched mesenteric lymphatic vessels that 'leak' HFD-lymph into VAT and, thereby, promote insulin resistance. Mesenteric lymphatic dysfunction is regulated by cyclooxygenase (COX)-2 and vascular endothelial growth factor (VEGF)-C-VEGF receptor (R)3 signalling. Lymph-targeted inhibition of COX-2 using a glyceride prodrug approach reverses mesenteric lymphatic dysfunction, visceral obesity and inflammation and restores glycaemic control in mice. Targeting obesity-associated mesenteric lymphatic dysfunction thus represents a potential therapeutic option to treat metabolic disease.

Gut Microbiota and Atherosclerosis-Focusing on the Plaque Stability

Cardiovascular diseases (CVDs) are major causes of mortality and morbidity in the modern society. The rupture of atherosclerotic plaque can induce thrombus formation, which is the main cause of acute cardiovascular events. Recently, many studies have demonstrated that there are some relationships between microbiota and atherosclerosis. In this review, we will focus on the effect of the microbiota and the microbe-derived metabolites, including trimethylamine-N-oxide (TMAO), short-chain fatty acids (SCFAs), and lipopolysaccharide (LPS), on the stability of atherosclerotic plaque. Finally, we will conclude with some therapies based on the microbiota and its metabolites.

New insights into lipopolysaccharide inactivation mechanisms in sepsis

The complex pathophysiology of sepsis makes it a syndrome with limited therapeutic options and a high mortality rate. Gram-negative bacteria containing lipopolysaccharides (LPS) in their outer membrane correspond to the most common cause of sepsis. Since the gut is considered an important source of LPS, intestinal damage has been considered a cause and a consequence of sepsis. Although important in the maintenance of the intestinal epithelial cell homeostasis, the microbiota has been considered a source of LPS. Recent studies have started to shed light on how sepsis is triggered by dysbiosis, and an increased inflammatory state of the intestinal epithelial cells, expanding the understanding of the gut-liver axis in sepsis. Here, we review the gut-liver interaction in Gram-negative sepsis, exploring the mechanisms of LPS inactivation, including the recently described contribution of an isoform of the cholesteryl-ester transfer protein (CETPI). Although several key questions remain to be answered when the pathophysiology of sepsis is reviewed, new contributions coming to light exploring the way LPS might be inactivated in vivo, suggest that new applications might soon reach the clinical setting.

Galactooligosaccharide pretreatment alleviates damage of the intestinal barrier and inflammatory responses in LPS-challenged mice

Galactooligosaccharides (GOS) have been identified as beneficial prebiotics for animals and human beings. Most studies have focused on the effect of GOS on the hindgut populated with abundant microbes. However, few research studies have been conducted on the small intestine, and many results are inconsistent due to the purity of GOS, commonly mixed with monosaccharides or lactose. Therefore, pure GOS with definite structures were prepared and used in the present study to evaluate their effects on intestinal barrier function, inflammatory responses and short-chain fatty acids (SCFAs) produced in the colon of mice challenged with lipopolysaccharide (LPS). The results of 1H and 13C nuclear magnetic resonance spectral analyses indicated that the main structures of GOS with a degree of polymerization of 3 (trisaccharide) and 4 (tetrasaccharide) are [β-Gal-(1 → 6)-β-Gal(1 → 4)-β-Glc] and [β-Gal-(1 → 6)-β-Gal-(1 → 6)-β-Gal-(1 → 4)-β-Glc], respectively. The results of an in vivo study in mice showed that intragastric administration of 0.5 g per kg BW GOS attenuated intestinal barrier damage and inflammatory responses induced by LPS in the jejunum and ileum, as indicated by increasing villus height and villus-to-crypt ratio, up-regulated intestinal tight junction (ZO-1, occludin, and claudin-1) gene expression, and down-regulated pro-inflammatory cytokines such as IL-1β, IL-6, IFN-γ, and TNF-α gene expression. Nevertheless, the protective effects of GOS on the intestinal barrier are independent of glucagon-like peptide 2. In addition, 0.5 g per kg BW GOS administration promoted the recovery of colonic acetate, propionate, butyrate, and total SCFA production reduced by LPS challenge. The obtained results provide practical evidence that pure GOS can act as protective agents for intestinal health.

From Obesity to Hippocampal Neurodegeneration: Pathogenesis and Non-Pharmacological Interventions

High-caloric diet and physical inactivity predispose individuals to obesity and diabetes, which are risk factors of hippocampal neurodegeneration and cognitive deficits. Along with the adipose-hippocampus crosstalk, chronically inflamed adipose tissue secretes inflammatory cytokine could trigger neuroinflammatory responses in the hippocampus, and in turn, impairs hippocampal neuroplasticity under obese and diabetic conditions. Hence, caloric restriction and physical exercise are critical non-pharmacological interventions to halt the pathogenesis from obesity to hippocampal neurodegeneration. In response to physical exercise, peripheral organs, including the adipose tissue, skeletal muscles, and liver, can secret numerous exerkines, which bring beneficial effects to metabolic and brain health. In this review, we summarized how chronic inflammation in adipose tissue could trigger neuroinflammation and hippocampal impairment, which potentially contribute to cognitive deficits in obese and diabetic conditions. We also discussed the potential mechanisms underlying the neurotrophic and neuroprotective effects of caloric restriction and physical exercise by counteracting neuroinflammation, plasticity deficits, and cognitive impairments. This review provides timely insights into how chronic metabolic disorders, like obesity, could impair brain health and cognitive functions in later life.

Microbiota Features Associated With a High-Fat/Low-Fiber Diet in Healthy Adults

A high intake of dietary saturated fatty acids (SFAs) is related to an increased risk of obesity, inflammation and cancer-related diseases, and this risk is attenuated only when SFAs are replaced by unsaturated fats and unrefined carbohydrates. The gut microbiota has recently emerged as a new environmental factor in the pathophysiology of these disorders, and is also one of the factors most influenced by diet. We sought to determine whether the gut microbiota of healthy individuals whose intake of SFAs exceeds World Health Organization (WHO) recommendations exhibits features similar to those reported in people with obesity, inflammation, cancer or metabolic disease. Healthy non-obese subjects were divided into two groups based on their SFAs intake. Body composition and gut microbiota composition were analyzed, and associations between bacterial taxa, diet and body fat composition were determined globally and separately by sex. Metagenome functional pathways were predicted by PICRUSt analysis. Subjects whose SFAs intake exceeded WHO recommendations also had a dietary pattern of low fiber intake. This high saturated fat/low fiber diet was associated with a greater sequence abundance of the Anaerotruncus genus, a butyrate producer associated with obesity. Analysis of data of high SFAs intake by sex showed that females presented with a greater abundance of Campylobacter, Blautia, Flavonifractor and Erysipelatoclostridium, whereas males showed higher levels of Anaerotruncus, Eisenbergiella, a genus from the order Clostridiales (FamilyXIIIUCG_001) and two genera from the Lachnospiraceae family. PICRUSt analysis confirmed these data, showing a correlation with a decrease in the abundance of sequences encoding for transporters of some metals such as iron, which is needed to maintain a healthy metabolism. Thus, the microbiota of healthy people on a high SFAs diet contain bacterial taxa (Anaerotruncus, Lachnospiraceae Flavonifractor, Campylobacter, Erysipelotrichacea and Eisenbergiella) that could be related to the development of some diseases, especially obesity and other pro-inflammatory diseases in women. In summary, the present study identifies bacterial taxa that could be considered as early predictors for the onset of different diseases in healthy subjects. Also, sex differences in gut microbiota suggest that women and men differentially benefit from following a specific diet.

Regulation of the intestinal barrier by nutrients: The role of tight junctions

Tight junctions (TJs) play an important role in intestinal barrier function. TJs in intestinal epithelial cells are composed of different junctional molecules, such as claudin and occludin, and regulate the paracellular permeability of water, ions, and macromolecules in adjacent cells. One of the most important roles of the TJ structure is to provide a physical barrier to luminal inflammatory molecules. Impaired integrity and structure of the TJ barrier result in a forcible activation of immune cells and chronic inflammation in different tissues. According to recent studies, the intestinal TJ barrier could be regulated, as a potential target, by dietary factors to prevent and reduce different inflammatory disorders, although the precise mechanisms underlying the dietary regulation remain unclear. This review summarizes currently available information on the regulation of the intestinal TJ barrier by food components.

Relationship of Zonulin with Serum PCSK9 Levels after a High Fat Load in a Population of Obese Subjects

Despite the fact that circulating levels of proprotein convertase subtilisin/kexin type 9 (PCSK9) remain unchanged after fat load in healthy lean individuals, PCSK9 has been suggested to have a role in postprandial lipemia regulation in obese individuals. On the other hand, intestinal permeability and endotoxemia have been observed to increase more in obese individuals than in non-obese individuals after a lipid load. This study aimed to analyze the relationship between PCSK9, intestinal permeability, and endotoxemia after a high fat load in obese individuals. We included 39 individuals with morbid obesity. Serum PCSK9 levels, intestinal permeability marker (zonulin), endotoxemia markers (LPS and LBP), and lipid parameters were measured before and after 3 h of fat load. A significant rise in triglycerides, apolipoprotein A1, zonulin, LPS, and LBP, and a significant decline in PCSK9, were observed after a lipid load. Linear regression analysis showed that low-density lipoprotein cholesterol (LDL-C) was independently related to PCSK9 at baseline, whereas both zonulin and LDL-C were independently related to PCSK9 levels after fat load. A relationship between zonulin and PCSK9 levels after fat load in individuals with morbid obesity may exist.

Effects of a Diet Supplemented with Exogenous Catalase from Penicillium notatum on Intestinal Development and Microbiota in Weaned Piglets

This study aims to investigate the effects of exogenous catalase (CAT), an antioxidative enzyme from microbial cultures, on intestinal development and microbiota in weaned piglets. Seventy-two weaned piglets were allotted to two groups and fed a basal diet or a basal diet containing 2.0 g/kg exogenous CAT. Results showed that exogenous CAT increased (p < 0.05) jejunal villus height/crypt depth ratio and intestinal factors (diamine oxidase and transforming growth factor-α) concentration. Moreover, dietary CAT supplementation enhanced the antioxidative capacity, and decreased the concentration of pro-inflammatory cytokine in the jejunum mucosa. Exogenous CAT did not affect the concentration of short-chain fatty acids, but decreased the pH value in colonic digesta (p < 0.05). Interestingly, the relative abundance of Bifidobacterium and Dialister were increased (p < 0.05), while Streptococcus and Escherichia-Shigella were decreased (p < 0.05) in colonic digesta by exogenous CAT. Accordingly, decreased (p < 0.05) predicted functions related to aerobic respiration were observed in the piglets fed the CAT diet. Our study suggests a synergic response of intestinal development and microbiota to the exogenous CAT, and provides support for the application of CAT purified from microbial cultures in the feed industry.

The Role of Interstitial Matrix and the Lymphatic System in Gastrointestinal Lipid and Lipoprotein Metabolism

This review emphasizes the events that take place after the chylomicrons are secreted by the enterocytes through exocytosis. First, we will discuss the journey of how chylomicrons cross the basement membrane to enter the lamina propria. Then the chylomicrons have to travel across the lamina propria before they can enter the lacteals. To understand the factors affecting the trafficking of chylomicron particles across the lamina propria, it is important to understand the composition and properties of the lamina propria. With different degree of hydration, the pores of the lamina propria (sponge) changes. The greater the hydration, the greater the pore size and thus the easier the diffusion of the chylomicron particles across the lamina propria to enter the lacteals. The mechanism of the entry of lacteals is discussed in considerable details. We and others have demonstrated that intestinal fat absorption, but not the absorption of protein or carbohydrates, activates the intestinal mucosal mast cells to release many products including mucosal mast cell protease II in the rat. The activation of intestinal mucosal mast cells by fat absorption involves the process of chylomicron formation since the absorption of both medium and short-chain fatty acids do not activate the mast cells. Fat absorption has been associated with increased intestinal permeability. We hypothesize that there is a link between fat absorption, activation of mucosal mast cells, and the leaky gut phenomenon (increased intestinal permeability). Microbiome may also be involved in this chain of events associated with fat absorption. This review is presented in sequence under the following headings: (1) Introduction; (2) Structure and properties of the gut epithelial basement membrane; (3) Composition and physical properties of the interstitial matrix of the lamina propria; (4) The movement of chylomicrons across the interstitial matrix of the lamina propria and importance of the hydration of the interstitial matrix of the lamina propria and the movement of chylomicrons; (5) Entry of the chylomicrons into the intestinal lacteals; (6) Activation of mucosal mast cells by fat absorption and the metabolic consequences; and (7) Link between chylomicron transport, mucosal mast cell activation, leaky gut, and the microbiome.

Intestinal Availability and Metabolic Effects of Dietary Camelina Sphingolipids during the Metabolic Syndrome Onset in Mice

Sphingolipids appear as a promising class of components susceptible to prevent the onset of the metabolic syndrome (MetS). Gut availability and effects of Camelina sativa sphingolipids were investigated in a mouse model of dietary-induced MetS. Seed meals from two Camelina sativa lines enriched, respectively, in C24- and C16-NH_2^- glycosyl-inositol-phosphoryl-ceramides (NH₂GIPC) were used in hypercaloric diets. After 5 weeks on these two hypercaloric diets, two markers of the MetS were alleviated (adiposity and insulin resistance) as well as inflammation markers and colon barrier dysfunction. A more pronounced effect was observed with the C16-NH₂GIPC-enriched HC diet, in particular for colon barrier function. Despite a lower digestibility, C16-NH₂GIPC were more prevalent in the intestine wall. Sphingolipids provided as camelina meal can therefore counteract some deleterious effects of a hypercaloric diet in mice at the intestinal and systemic levels. Interestingly, these beneficial effects seem partly dependent on sphingolipid acyl chain length.

Dietary fat intake and age modulate the composition of the gut microbiota and colonic inflammation in C57BL/6J mice

Background

More than half of the adult population worldwide is overweight or obese, while excess adiposity has been linked to chronic low-grade inflammation, contributing to the development of chronic diseases. Recent studies have showed that diet-induced alterations to the gut microbiota composition play a pivotal role in the development of obesity. However, the cause-effect relationship between obesity and gut microbiota composition is not yet fully understood. In this study, we investigated the short-term responses of gut microbiota composition to diets with different fat contents and their associations with inflammatory biomarkers.

Results

Sixty male C57BL/6 J mice were fed a normal diet (ND; 15% fat) or a high-fat diet (HFD; 45% fat) for 10 or 20 weeks. The relative proportion of the phylum Actinobacteria was elevated by the HFD and was positively associated with body weight and proinflammatory cytokines including TNF-α, IL-1β, and IL-6. The proportion of the phylum Firmicutes increased with aging and was also positively correlated with proinflammatory cytokines. The proportions of Actinobacteria and Firmicutes were inversely associated with tight junction proteins claudin-1 and E-cadherin, respectively. The proportions of the class Clostridia and the family Ruminococcaceae within the phylum Firmicutes were affected by both diet and age. In addition, the proportions of the phylum Bacteroidetes, the family Bacteroidaceae, and the genus Bacteroides decreased with aging and were inversely correlated with colonic proinflammatory cytokines representing a positive association with tight junction proteins.

Conclusions

Host age and dietary fat intake are important elements that induce proportional changes in gut microbiota, and these changes are also associated with systemic inflammation. This study provides evidence that diet affects the gut microbiota composition within a short period of time.

Dynamic changes in basal lamina fenestrations in rat intestinal villous epithelium under high-fat diet condition

The basal lamina of the villous epithelium in the small intestine has numerous fenestrations, which are produced by leukocytes for their intraepithelial migration. We previously showed that these fenestrations change due to the dynamics of migrating leukocytes in response to dietary conditions and suggested the possibility that this change is related to the regulation of the absorption of large-sized nutrients such as chylomicrons. The present study was, thus, designed to investigate structural changes in basal lamina fenestrations in response to a high-fat diet. The ultrastructure of the intestinal villi in the rat upper jejunum was investigated by electron microscopy of tissue sections in both the normal and the high-fat diet groups, and the fenestrations in the villous epithelium of rat upper jejunum were studied by scanning electron microscopy of osmium macerated/ ultrasonicated tissues. The present study showed that free cells adhering to the fenestrations increased in the upper jejunum two hours after feeding high-fat diet and the size of the fenestrations in this region also increased after feeding high-fat diet for 2 days. This enlargement of fenestrations may play an important role in increasing the efficiency of lipid absorption by facilitating the movement of chylomicrons from the intercellular space to the lamina propria.

Meat proteins in a high-fat diet have a substantial impact on intestinal barriers through mucus layer and tight junction protein suppression in C57BL/6J mice

Protein diets are well known for body maintenance and weight loss.

Inflammation of brown/beige adipose tissues in obesity and metabolic disease

Many of the comorbidities of obesity, including type 2 diabetes and cardiovascular diseases, are related to the low-grade chronic inflammation of white adipose tissue. Under white adipocyte stress, local infiltration of immune cells and enhanced production of pro-inflammatory cytokines together reduce metabolic flexibility and lead to insulin resistance in obesity. Whereas white adipocytes act in energy storage, brown and beige adipocytes specialize in energy expenditure. Brown and beige activity protects against obesity and associated metabolic disorders, such as hyperglycaemia and hyperlipidaemia. Compared to white fat, brown adipose tissue depots are less susceptible to developing local inflammation in response to obesity; however, strong obesogenic insults ultimately induce a locally pro-inflammatory environment in brown fat. This condition directly alters the thermogenic activity of brown fat by impairing its energy expenditure mechanism and uptake of glucose for use as a fuel substrate. Pro-inflammatory cytokines also impair beige adipogenesis, which occurs mainly in subcutaneous adipose tissue. There is evidence that inflammatory processes occurring in perivascular adipose tissues alter their brown-versus-white plasticity, impair the extent of browning in these depots and favour the local release of vasculature damaging signals. In summary, the targeting of brown and beige adipose tissues by pro-inflammatory signals and the subsequent impairment of their thermogenic and metabolite draining activities appears to represent obesity-driven disturbances that contribute to metabolic syndrome and cardiovascular alterations in obesity.

Food influence on lead relative bioavailability in contaminated soils: Mechanisms and health implications

To determine the effects of dietary constituents on soil Pb oral bioavailability, Pb relative bioavailability (RBA) in 3 soils contaminated by zinc smelting (ZS), wire-rope production (WR), and metal mining (MM) was measured under fasted and fed states with 9 foods. Under fasted state, Pb-RBA was 84.4 ± 10.3, 82.6 ± 4.70, and 32.3 ± 1.10% for ZS, WR, and MM soils; however, it decreased by 1.3-3.5 fold to 23.9-58.8, 25.6-49.9, and 14.8-24.2% under fed states with foods excluding Pb-RBA with egg in WR soil (97.3 ± 4.46%), and with cabbage and egg in MM soil (40.0 ± 8.62 and 44.4 ± 0.96%). In the presence of foods, egg and pork with significantly higher protein and fat contents leaded to the highest soil Pb-RBA (44.4-97.3%), while Pb-RBA determined with mineral-rich mouse feed was 1.6-7.9 fold lower (9.41-13.5%), suggesting high fat and protein foods tended to increase soil Pb-RBA, while high mineral diets decreased soil Pb-RBA. The increased Pb-RBA of MM soil with cabbage compared to fasted state was due to high organic content in cabbage, which could increase soil Pb solubility by inhibiting Fe and Pb co-precipitation in the intestine. For accurate assessment of health risks of contaminated soils, dietary influence on soil Pb-RBA should be considered.

Excess of nutrient-induced morphofunctional adaptation and inflammation degree in a Caco2/HT-29 in vitro intestinal co-culture

OBJECTIVES

The intestinal cell function can be modulated by the type and quantity of nutrients. The aim of this study was to evaluate the effects of an excess of nutrients on intestinal morphofunctional features and a possible association of inflammation in a 70/30 Caco2/HT-29 intestinal in vitro co-culture.

METHODS

An excess of nutrients (EX) was obtained by progressively increasing the medium change frequency with respect to standard cell growth conditions (ST) from confluence (T0) to 15 d after confluence (T15).

RESULTS

In comparison with the ST group, the EX group revealed a maintenance in the number of microvilli, an increase in follicle like-structures and mucus production, and a decrease in the number of tight junction. The specific activity of markers of intestinal differentiation, alkaline phosphatase and aminopeptidase N, and of the enterocyte differentiation specific marker, dipeptidyl peptidase-IV, were progressively raised. The transepithelial electrical resistance, indicative of the co-culture barrier properties, decreased, whereas Lucifer yellow P_app evaluation, an index of the paracellular permeability to large molecules, showed an increase. Reactive oxygen species and nitric oxide production, indicative of an oxidative status, together with interleukin-6, interleukin-8, indicative of a low-grade inflammation, and peptide YY secretion were higher in the EX group than in the ST group. The differences between ST and EX were particularly evident at T15.

CONCLUSION

These data support the suitability of our in vitro gut model for obesity studies at the molecular level and the necessity to standardize the medium frequency change in intestinal culture.

Impact of Omega-3 Fatty Acids on the Gut Microbiota

Long-term dietary habits play a crucial role in creating a host-specific gut microbiota community in humans. Despite the many publications about the effects of carbohydrates (prebiotic fibers), the impact of dietary fats, such as omega-3 polyunsaturated fatty acids (PUFAs), on the gut microbiota is less well defined. The few studies completed in adults showed some common changes in the gut microbiota after omega-3 PUFA supplementation. In particular, a decrease in Faecalibacterium, often associated with an increase in the Bacteroidetes and butyrate-producing bacteria belonging to the Lachnospiraceae family, has been observed. Coincidentally, a dysbiosis of these taxa is found in patients with inflammatory bowel disease. Omega-3 PUFAs can exert a positive action by reverting the microbiota composition in these diseases, and increase the production of anti-inflammatory compounds, like short-chain fatty acids. In addition, accumulating evidence in animal model studies indicates that the interplay between gut microbiota, omega-3 fatty acids, and immunity helps to maintain the intestinal wall integrity and interacts with host immune cells. Finally, human and animal studies have highlighted the ability of omega-3 PUFAs to influence the gut–brain axis, acting through gut microbiota composition. From these findings, the importance of the omega-3 connection to the microbiota emerges, encouraging further studies.

Diet as a Therapeutic Option for Adult Inflammatory Bowel Disease

There are many mechanisms to explain how food may drive and ameliorate inflammation. Although there are no consistent macronutrient associations inflammatory bowel disease (IBD) development, many exclusion diets have been described: IgG-4 guided exclusion diet; semivegetarian diet; low-fat, fiber-limited exclusion diet; Paleolithic diet; Maker's diet; vegan diet; Life without Bread diet; exclusive enteral nutrition (EEN), the Specific Carbohydrate Diet (SCD) and the low FODMAP diet. The literature on diet and IBD is reviewed with a particular focus on EEN, SCD, and low FODMAP diets. Lessons learned from the existing observations and strengths and shortcomings of existing data are presented.

Dietary sphingolipids: potential for management of dyslipidemia and nonalcoholic fatty liver disease

The development of therapeutic approaches aimed at reducing inflammation, improving lipid metabolism, and preventing nonalcoholic fatty liver disease holds significant potential in the management of obesity-associated disease. In this review, the recent basic science and clinical research examining dietary sphingolipid intake and the prevention of dyslipidemia and nonalcoholic fatty liver disease is summarized. Dietary sphingolipids have been shown to dose-dependently reduce the acute intestinal absorption of cholesterol, triglycerides, and fatty acids in rodents. Overall, studies feeding dietary sphingolipids to rodents typically show reductions in serum lipids. Furthermore, these hypolipidemic effects are also observed in most human studies, although the magnitude of such effects is typically smaller. Dietary sphingolipids also appear useful in preventing hepatic lipid uptake and accumulation and have shown benefits in preventing hepatic steatosis in rodent models. Dietary sphingolipids may affect the gut-liver axis by preventing the translocation of gut bacteria-derived lipopolysaccharide and/or inhibiting its proinflammatory effects. Current evidence from preclinical studies indicates that dietary sphingolipids have lipid-lowering and anti-inflammatory properties, although their potential to prevent human chronic disease has not been fully explored. It will be important to determine if such effects seen in cell and animal models translate to humans. More research is warranted to define how dietary sphingolipids influence lipid metabolism and inflammation.

Impact of dietary fat on gut microbiota and low-grade systemic inflammation: mechanisms and clinical implications on obesity

Dietary fat strongly affects human health by modulating gut microbiota composition and low-grade systemic inflammation. High-fat diets have been implicated in reduced gut microbiota richness, increased Firmicutes to Bacteroidetes ratio, and several changes at family, genus and species levels. Saturated (SFA), monounsaturated (MUFA), polyunsaturated (PUFA) and conjugated linolenic fatty acids share important pathways of immune system activation/inhibition with gut microbes, modulating obesogenic and proinflammatory profiles. Mechanisms that link dietary fat, gut microbiota and obesity are mediated by increased intestinal permeability, systemic endotoxemia, and the activity of the endocannabinoid system. Although the probiotic therapy could be a complementary strategy to improve gut microbiota composition, it did not show permanent effects to treat fat-induced dysbiosis. Based upon evidence to date, we believe that high-fat diets and SFA consumption should be avoided, and MUFA and omega-3 PUFA intake should be encouraged in order to regulate gut microbiota and inflammation, promoting body weight/fat control.

Probiotic mixture improves fatty liver disease by virtue of its action on lipid profiles, leptin, and inflammatory biomarkers

BACKGROUND

A high fat diet has an essential role in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). This condition is characterized by hepatic fat accumulation (steatosis) and is associated with obesity, diabetes, and fibrosis or cirrhosis of the liver. Probiotics may be useful in the treatment of steatosis. This study examined the effects of an ingested probiotic formulation on the lipid profiles, liver functions, leptin levels, and inflammatory marker levels of rats with NAFLD that had been induced via high fat and sucrose diet (HFSD).

METHODS

Young male albino rats were randomly divided into three groups: a control group that was fed a standard diet; a second group that was fed a HFSD; and a third group that was given both a HFSD and ingestible probiotic mixtures. The groups were fed these diets for 16 weeks, and were then examined.

RESULTS

HFSD-only rats showed hypertriglyceridemia, hypercholesterolemia, and elevated low density lipoprotein (LDL) levels, and their serum alanine transaminase (ALT) and bilirubin levels were significantly higher than those of the control group. Compared to rats on the standard diet, HFSD-only rats showed higher levels of tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6), increased serum leptin levels, and increased resistin hormone levels in the adipose tissues. In the third group, the inclusion of the probiotic mixture seemed to ameliorate the effects of the HFSD diet. The NAFD + probiotics group showed improved lipid profiles, better leptin and resistin levels, and better TNF-α and IL-6 levels than the NAFD-only group. They also showed no signs of NAFLD.

CONCLUSIONS

The probiotic mixture showed promise as a treatment for NAFLD pathogenesis, and may improve HFSD-induced steatosis through its effects on leptin, resistin, inflammatory biomarkers, and hepatic function markers. We also established that gut microbiota-mediated regulation of lipid profiles was dependent on dietary lipids and carbohydrates.

Chronic psychological stress and high-fat high-fructose diet disrupt metabolic and inflammatory gene networks in the brain, liver, and gut and promote behavioral deficits in mice

The mechanisms underlying the association between chronic psychological stress, development of metabolic syndrome (MetS), and behavioral impairment in obesity are poorly understood. The aim of the present study was to assess the effects of mild chronic psychological stress on metabolic, inflammatory, and behavioral profiles in a mouse model of diet-induced obesity. We hypothesized that (1) high-fat high-fructose diet (HFHF) and psychological stress would synergize to mediate the impact of inflammation on the central nervous system in the presence of behavioral dysfunction, and that (2) HFHF and stress interactions would impact insulin and lipid metabolism. C57Bl/6 male mice underwent a combination of HFHF and two weeks of chronic psychological stress. MetS-related conditions were assessed using untargeted plasma metabolomics, and structural and immune changes in the gut and liver were evaluated. Inflammation was measured in plasma, liver, gut, and brain. Our results show a complex interplay of diet and stress on gut alterations, energetic homeostasis, lipid metabolism, and plasma insulin levels. Psychological stress and HFHF diet promoted changes in intestinal tight junctions proteins and increases in insulin resistance and plasma cholesterol, and impacted the RNA expression of inflammatory factors in the hippocampus. Stress promoted an adaptive anti-inflammatory profile in the hippocampus that was abolished by diet treatment. HFHF increased hippocampal and hepatic Lcn2 mRNA expression as well as LCN2 plasma levels. Behavioral changes were associated with HFHF and stress. Collectively, these results suggest that diet and stress as pervasive factors exacerbate MetS-related conditions through an inflammatory mechanism that ultimately can impact behavior. This rodent model may prove useful for identification of possible biomarkers and therapeutic targets to treat metabolic syndrome and mood disorders.

Monosodium glutamate inhibits the lymphatic transport of lipids in the rat

It is not well understood how monosodium glutamate (MSG) affects gastrointestinal physiology, especially regarding the absorption and the subsequent transport of dietary lipids into lymph. Thus far, there is little information about how the ingestion of MSG affects the lipid lipolysis, uptake, intracellular esterification, and formation and secretion of chylomicrons. Using lymph fistula rats treated with the infusion of a 2% MSG solution before a continuous infusion of triglyceride, we show that MSG causes a significant decrease in both triglyceride and cholesterol secretion into lymph. Intriguingly, the diminished lymphatic transport of triglyceride and cholesterol was not caused by an accumulation of these labeled lipids in the intestinal lumen or in the intestinal mucosa. Rather, it is a result of increased portal transport in the animals fed acutely the lipid plus 2% MSG in the lipid emulsion. This is a first demonstration of MSG on intestinal lymphatic transport of lipids.

New utility of an old marker: serum low-density lipoprotein predicts histopathological response of neoadjuvant chemotherapy in locally advanced gastric cancer

Background

Although the correlation between metabolic abnormality and gastric cancer has been extensively investigated, the question of whether metabolic parameters might influence the efficacy of chemotherapy in locally advanced gastric cancer is still unanswered. In our present study, we investigated the relationship between serum fasting glucose, lipid levels, and histopathological response of neoadjuvant chemotherapy (NAC) in locally advanced gastric cancers.

Patients and methods

A total of 128 patients were identified from a prospectively maintained database of patients with locally advanced gastric cancer who received NAC between July 2004 and December 2012. Histopathological response after NAC was analyzed according to Becker’s tumor-regression grade. Univariate analyses and multivariable regression analyses were performed to determine the correlation between tumor size, differentiation, fasting glucose, lipid levels, and tumor histopathological response after NAC.

Results

Univariate analysis revealed that low-density lipoprotein level and total cholesterol, as well as tumor size and differentiation, correlated significantly with histopathological response. Low-density lipoprotein levels and tumor size were found to be independent predictors for histopathological response, according to multivariable regression analyses.

Conclusion

In this observational, hypothesis-generating study, serum low-density lipoprotein measurement was found to be useful in predicting chemosensitivity to locally advanced gastric cancer patients undergoing NAC. Incorporation of serum low-density lipoprotein levels into individualized treatment protocols could be considered in clinical practice.

Body mass index, serum total cholesterol, and risk of gastric high-grade dysplasia: A case-control study among Chinese adults

Obesity is related to an increased risk of gastric cardia cancer. However, the influences of excess body weight and serum total cholesterol on the risk of gastric high-grade dysplasia have not been fully characterized.A case-control study was conducted to explore the relationships between body mass index (BMI), serum total cholesterol level, and the risk of gastric high-grade dysplasia in Chinese adults. A total of 893 consecutive patients with gastric high-grade dysplasia (537 men and 356 women) and 902 controls (543 men and 359 women) were enrolled from January 2000 to October 2015. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated, and a multivariate analysis was conducted.After adjusting for age, alcohol consumption, smoking status, family history of gastric cancer or esophageal cancer, and serum total cholesterol level, a BMI ranging from 27.5 to 29.9 was significantly related to an increased risk of gastric high-grade dysplasia in both men (adjusted OR = 1.87, 95% CI = 1.24-2.81) and women (adjusted OR = 2.72, 95% CI = 1.44-5.16). The 2 highest BMI categories (27.5-29.9 and ≥30.0) were identified as risk factors for gastric cardia high-grade dysplasia in both men (BMI = 27.5-29.9: adjusted OR = 1.78, 95% CI = 1.02-3.10; BMI ≥ 30.0: adjusted OR = 2.54, 95% CI = 1.27-5.08) and women (BMI = 27.5-29.9: adjusted OR = 2.88, 95% CI = 1.27-6.55; BMI ≥ 30.0: adjusted OR = 2.77, 95% CI = 1.36-5.64), whereas only a BMI ranging from 27.5 to 29.9 was a risk factor for gastric noncardia high-grade dysplasia in both men (adjusted OR = 1.98, 95% CI = 1.25-3.14) and women (adjusted OR = 2.88, 95% CI = 1.43-5.81). In addition, higher serum total cholesterol was associated with an increased risk of gastric noncardia high-grade dysplasia (adjusted OR = 1.83, 95% CI = 1.25-2.69) in women.Increased BMI was associated with an increased risk of gastric high-grade dysplasia in both men and women, and higher serum total cholesterol increased the risk of gastric noncardia high-grade dysplasia in women.

Gut microbiota-derived lipopolysaccharide uptake and trafficking to adipose tissue: implications for inflammation and obesity

The composition of the gut microbiota and excessive ingestion of high-fat diets (HFD) are considered to be important factors for development of obesity. In this review we describe a coherent mechanism of action for the development of obesity, which involves the composition of gut microbiota, HFD, low-grade inflammation, expression of fat translocase and scavenger receptor CD36, and the scavenger receptor class B type 1 (SR-BI). SR-BI binds to both lipids and lipopolysaccharide (LPS) from Gram-negative bacteria, which may promote incorporation of LPS in chylomicrons (CMs). These CMs are transported via lymph to the circulation, where LPS is transferred to other lipoproteins by translocases, preferentially to HDL. LPS increases the SR-BI binding, transcytosis of lipoproteins over the endothelial barrier,and endocytosis in adipocytes. Especially large size adipocytes with high metabolic activity absorb LPS-rich lipoproteins. In addition, macrophages in adipose tissue internalize LPS-lipoproteins. This may contribute to the polarization from M2 to M1 phenotype, which is a consequence of increased LPS delivery into the tissue during hypertrophy. In conclusion, evidence suggests that LPS is involved in the development of obesity as a direct targeting molecule for lipid delivery and storage in adipose tissue.

Crosstalk between intestinal microbiota, adipose tissue and skeletal muscle as an early event in systemic low-grade inflammation and the development of obesity and diabetes

Obesity is associated with a systemic chronic low-grade inflammation that contributes to the development of metabolic disorders such as cardiovascular diseases and type 2 diabetes. However, the etiology of this obesity-related pro-inflammatory process remains unclear. Most studies have focused on adipose tissue dysfunctions and/or insulin resistance in skeletal muscle cells as well as changes in adipokine profile and macrophage recruitment as potential sources of inflammation. However, low-grade systemic inflammation probably involves a complex network of signals interconnecting several organs. Recent evidences have suggested that disturbances in the composition of the gut microbial flora and alterations in levels of gut peptides following the ingestion of a high-fat diet may be a cause of low-grade systemic inflammation that may even precede and predispose to obesity, metabolic disorders or type 2 diabetes. This hypothesis is appealing because the gastrointestinal system is first exposed to nutrients and may thereby represent the first link in the chain of events leading to the development of obesity-associated systemic inflammation. Therefore, the present review will summarize the latest advances interconnecting intestinal mucosal bacteria-mediated inflammation, adipose tissue and skeletal muscle in a coordinated circuitry favouring the onset of a high-fat diet-related systemic low-grade inflammation preceding obesity and predisposing to metabolic disorders and/or type 2 diabetes. A particular emphasis will be given to high-fat diet-induced alterations of gut homeostasis as an early initiator event of mucosal inflammation and adverse consequences contributing to the promotion of extended systemic inflammation, especially in adipose and muscular tissues.

The gut-adipose-liver axis in the metabolic syndrome

Obesity is associated with altered gut microbiota composition and impaired gut barrier function. These changes, together with interrelated mesenteric adipose tissue inflammation, result in increased release of pro-inflammatory cytokines, bacteria-derived factors, and lipids into the portal circulation, promoting the development of (hepatic) insulin resistance. Herein, the potential impact of obesity-related changes in gut and visceral adipose tissue biology on the development of insulin resistance and Type 2 diabetes is reviewed.

What is known about the mechanisms of dietary influences in Crohn's disease?

Much has been written about the role of diet and risk for Crohn's disease (CD). However, the evidence is contradictory. Recent evidence has pointed to fiber playing an important role along with the possibility that dietary fat and overnutrition also have a role. Diet has a clearer place in disease modification, with some diets used in the treatment of CD. The lack of clarity stems from a poor understanding of the mechanisms underlying the relationship between diet and CD. Gut permeability is likely to play a key role in the risk for CD. Mechanisms whereby diet can affect gut permeability, including the effects of the gut microbiota, are reviewed. Modification of disease behavior is likely to be influenced by additional mechanisms, including recognition of complex food antigens. As with many other chronic diseases, a surrogate marker of CD risk would greatly aid evaluation of the dietary factors involved. Formal measures of gut permeability are too cumbersome for large-scale use, but fecal calprotectin may be a convenient measure of this. There are only preliminary data on the effect of diet and microbiota composition on fecal calprotectin and these require further investigation.

Effect of Probiotic Lactobacillus salivarius UBL S22 and Prebiotic Fructo-oligosaccharide on Serum Lipids, Inflammatory Markers, Insulin Sensitivity, and Gut Bacteria in Healthy Young Volunteers: A Randomized Controlled Single-Blind Pilot Study

This study investigated the effect of 6-week supplementation of a probiotic strain Lactobacillus salivarius UBL S22 with or without prebiotic fructo-oligosaccharide (FOS) on serum lipid profiles, immune responses, insulin sensitivity, and gut lactobacilli in 45 healthy young individuals. The patients were divided into 3 groups (15/group), that is, placebo, probiotic, and synbiotic. After 6 weeks, a significant reduction (P < .05) in total cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides and increase in high-density lipoprotein cholesterol was observed in the probiotic as well as in the synbiotic group when compared to placebo; however, the results of total cholesterol and LDL-cholesterol were more pronounced in the synbiotic group. Similarly, when compared to the placebo group, the serum concentrations of inflammatory markers such as high sensitivity C-reactive protein, interleukin (IL) 6, IL-1β, and tumor necrosis factor α were significantly (P < .05) reduced in both the experimental groups, but again the reduction in the synbiotic group was more pronounced. Also, an increase (P < .05) in the fecal counts of total lactobacilli and a decrease (P < .05) in coliforms and Escherichia coli was observed in both the experimental groups after 6 weeks of ingestion. Overall, the combination of L salivarius with FOS was observed to be more beneficial than L salivarius alone, thereby advocating that such synbiotic combinations could be therapeutically exploited for improved health and quality of life.

The real role of prediagnostic high-density lipoprotein cholesterol and the cancer risk: a concise review

BACKGROUND

In several observational and clinical studies, the association between serum cholesterol levels and cancer is still unsettled although serum total cholesterol has been associated with increased mortality from cancer. Moreover, the importance of abnormal levels of serum lipid components as the main features of dyslipidemia and the risk of individual cancers is unclear. The prevalence of dyslipidemia is increasing worldwide but, the precise aetiology of the link between risk of cancer and the behaviour of lipid profile, prior diagnosis, has yet to be determinated. Low levels of high-density lipoprotein cholesterol (HDL) at baseline of many of the studies analyzed has to be taken into account, and continued low levels of HDL without explanation should be considered by clinicians.

AIMS

The main aim of this review was to undertake the assessment of the most recent studies implying the lipid profile and cancer risk, and focused on low HDL levels at baseline and follow up, and also analyzing this behaviour on the different cancer types.

MATERIAL AND METHODS

A literature search was performed to identify publications. The most recent prospective and case-control studies with multivariate Cox models were analyzed and also were considered some recent meta-analyses.

RESULTS AND CONCLUSIONS

The findings exposed in this review suggest that the association with low HDL levels at baseline of different studies of cancer risk is shared among many types of cancer, and it is mainly linked to obesity and inflammation, suggesting a common pathway.