Palmitic acid damages gut epithelium integrity and initiates inflammatory cytokine production

Effects of altering the ratio of C16:0 and cis-9 C18:1 in rumen bypass fat on growth performance, lipid metabolism, intestinal barrier, cecal microbiota, and inflammation in fattening bulls

BACKGROUND

C16:0 and cis-9 C18:1 may have different effects on animal growth and health due to unique metabolism in vivo. This study was investigated to explore the different effects of altering the ratio of C16:0 and cis-9 C18:1 in fat supplements on growth performance, lipid metabolism, intestinal barrier, cecal microbiota, and inflammation in fattening bulls. Thirty finishing Angus bulls (626 ± 69 kg, 21 ± 0.5 months) were divided into 3 treatments according to the randomized block design: (1) control diet without additional fat (CON), (2) CON + 2.5% palmitic acid calcium salt (PA, 90% C16:0), and (3) CON + 2.5% mixed fatty acid calcium salt (MA, 60% C16:0 + 30% cis-9 C18:1). The experiment lasted for 104 d, after which all the bulls were slaughtered and sampled for analysis.

RESULTS

MA tended to reduce 0-52 d dry matter intake compared to PA (DMI, P = 0.052). Compared with CON and MA, PA significantly increased 0-52 d average daily gain (ADG, P = 0.027). PA tended to improve the 0-52 d feed conversion rate compared with CON (FCR, P = 0.088). Both PA and MA had no significant effect on 52-104 days of DMI, ADG and FCR (P > 0.05). PA tended to improve plasma triglycerides compared with MA (P = 0.077), significantly increased plasma cholesterol (P = 0.002) and tended to improve subcutaneous adipose weight (P = 0.066) when compared with CON and MA. Both PA and MA increased visceral adipose weight compared with CON (P = 0.021). Only PA increased the colonization of Rikenellaceae, Ruminococcus and Proteobacteria in the cecum, and MA increased Akkermansia abundance (P < 0.05). Compared with CON, both PA and MA down-regulated the mRNA expression of Claudin-1 in the jejunum (P < 0.001), increased plasma diamine oxidase (DAO, P < 0.001) and lipopolysaccharide (LPS, P = 0.045). Compared with CON and MA, PA down-regulated the ZO-1 in the jejunum (P < 0.001) and increased plasma LPS-binding protein (LBP, P < 0.001). Compared with CON, only PA down-regulated the Occludin in the jejunum (P = 0.013). Compared with CON, PA and MA significantly up-regulated the expression of TLR-4 and NF-κB in the visceral adipose (P < 0.001) and increased plasma IL-6 (P < 0.001). Compared with CON, only PA up-regulated the TNF-α in the visceral adipose (P = 0.01). Compared with CON and MA, PA up-regulated IL-6 in the visceral adipose (P < 0.001), increased plasma TNF-α (P < 0.001), and reduced the IgG content in plasma (P = 0.035). Compared with CON, PA and MA increased C16:0 in subcutaneous fat and longissimus dorsi muscle (P < 0.05), while more C16:0 was also deposited by extension and desaturation into C18:0 and cis-9 C18:1. However, neither PA nor MA affected the content of cis-9 C18:1 in longissimus dorsi muscle compared with CON (P > 0.05).

CONCLUSIONS

MA containing 30% cis-9 C18:1 reduced the risk of high C16:0 dietary fat induced subcutaneous fat obesity, adipose tissue and systemic low-grade inflammation by accelerating fatty acid oxidative utilization, improving colonization of Akkermansia, reducing intestinal barrier damage, and down-regulating NF-κB activation.

High-fat diet enhances cell proliferation and compromises intestinal permeability in a translational canine intestinal organoid model

BACKGROUND

Emerging evidence underscores the responsiveness of the mammalian intestine to dietary cues, notably through the involvement of LGR5 + intestinal stem cells in orchestrating responses to diet-driven signals. However, the effects of high-fat diet (HFD) on these cellular dynamics and their impact on gut integrity remain insufficiently understood. Our study aims to assess the multifaceted interactions between palmitic acid (PA), cell proliferation, and the intestinal epithelial barrier using a canine colonoid model. Canine models, due to their relevance in simulating human intestinal diseases, offer a unique platform to explore the molecular mechanisms underlying HFD derived intestinal dysfunction.

RESULTS

Canine colonoids were subjected to PA exposure, a surrogate for the effects of HFD. This intervention revealed a remarkable augmentation of cell proliferative activity. Furthermore, we observed a parallel reduction in transepithelial electrical resistance (TEER), indicating altered epithelium barrier integrity. While E-cadherin exhibited consistency, ZO-1 displayed a noteworthy reduction in fluorescence intensity within the PA-exposed group.

CONCLUSIONS

By employing canine intestinal organoid systems, we provide compelling insights into the impact of PA on intestinal physiology. These findings underscore the importance of considering both cell proliferative activity and epithelial integrity in comprehending the repercussions of HFDs on intestinal health. Our study contributes to a deeper understanding of the consequences of HFD on intestinal homeostasis, utilizing valuable translational in vitro models derived from dogs.

A ketogenic diet rich in fish oil is superior to other fats in preventing NNK-induced lung cancer in A/J mice

Given that ketogenic diets (KDs) are extremely high in dietary fat, we compared different fats in KDs to determine which was the best for cancer prevention. Specifically, we compared a Western and a 15% carbohydrate diet to seven different KDs, containing either Western fats or fats enriched in medium chain fatty acids (MCTs), milk fat (MF), palm oil (PO), olive oil (OO), corn oil (CO) or fish oil (FO) for their ability to reduce nicotine-derived nitrosamine ketone (NNK)-induced lung cancer in mice. While all the KDs tested were more effective at reducing lung nodules than the Western or 15% carbohydrate diet, the FO-KD was most effective at reducing lung nodules. Correlating with this, mice on the FO-KD had low blood glucose and the highest β-hydroxybutyrate level, lowest liver fatty acid synthase/carnitine palmitoyl-1a ratio and a dramatic increase in fecal Akkermansia. We found no liver damage induced by the FO-KD, while the ratio of total cholesterol/HDL was unchanged on the different diets. We conclude that a FO-KD is superior to KDs enriched in other fats in reducing NNK-induced lung cancer, perhaps by being the most effective at skewing whole-body metabolism from a dependence on glucose to fats as an energy source.

Gut-brain communication mediates the impact of dietary lipids on cognitive capacity

Cognitive impairment, as a prevalent symptom of nervous system disorders, poses one of the most challenging aspects in the management of brain diseases. Lipids present in the cell membranes of all neurons within the brain and dietary lipids can regulate the cognition and memory function. In recent years, the advancements in gut microbiome research have enabled the exploration of dietary lipids targeting the gut-brain axis as a strategy for regulating cognition. This present review provides an in-depth overview of how lipids modulate cognition via the gut-brain axis depending on metabolic, immune, neural and endocrine pathways. It also comprehensively analyzes the effects of diverse lipids on the gut microbiota and intestinal barrier function, thereby affecting the central nervous system and cognitive capacity. Moreover, comparative analysis of the positive and negative effects is presented between beneficial and detrimental lipids. The former encompass monounsaturated fatty acids, short-chain fatty acids, omega-3 polyunsaturated fatty acids, phospholipids, phytosterols, fungal sterols and bioactive lipid-soluble vitamins, as well as lipid-derived gut metabolites, whereas the latter (detrimental lipids) include medium- or long-chain fatty acids, excessive proportions of n-6 polyunsaturated fatty acids, industrial trans fatty acids, and zoosterols. To sum up, the focus of this review is on how gut-brain communication mediates the impact of dietary lipids on cognitive capacity, providing a novel theoretical foundation for promoting brain cognitive health and scientific lipid consumption patterns.

Saturated fatty acids differently affect mitochondrial function and the intestinal epithelial barrier depending on their chain length in the in vitro model of IPEC-J2 enterocytes

Introduction: Maintenance of the intestinal barrier mainly relies on the mitochondrial function of intestinal epithelial cells that provide ATP through oxidative phosphorylation (OXPHOS). Dietary fatty acid overload might induce mitochondrial dysfunction of enterocytes and may increase intestinal permeability as indicated by previous in vitro studies with palmitic acid (C16:0). Yet the impact of other dietary saturated fatty acids remains poorly described. Methods: To address this question, the in vitro model of porcine enterocytes IPEC-J2 was treated for 3 days with 250 µM of lauric (C12:0), myristic (C14:0), palmitic (C16:0) or stearic (C18:0) acids. Results and discussion: Measurement of the transepithelial electrical resistance, reflecting tight junction integrity, revealed that only C16:0 and C18:0 increased epithelial permeability, without modifying the expression of genes encoding tight junction proteins. Bioenergetic measurements indicated that C16:0 and C18:0 were barely β-oxidized by IPEC-J2. However, they rather induced significant OXPHOS uncoupling and reduced ATP production compared to C12:0 and C14:0. These bioenergetic alterations were associated with elevated mitochondrial reactive oxygen species production and mitochondrial fission. Although C12:0 and C14:0 treatment induced significant lipid storage and enhanced fusion of the mitochondrial network, it only mildly decreased ATP production without altering epithelial barrier. These results point out that the longer chain fatty acids C16:0 and C18:0 increased intestinal permeability, contrary to C12:0 and C14:0. In addition, C16:0 and C18:0 induced an important energy deprivation, notably via increased proton leaks, mitochondrial remodeling, and elevated ROS production in enterocytes compared to C12:0 and C14:0.

Effect of Digested Selected Food Items on Markers of Oxidative Stress and Inflammation in a Caco-2-Based Human Gut Epithelial Model

The human gut epithelium presents a crucial interface between ingested food items and the host. Understanding how different food items influence oxidative stress and inflammation in the gut is of great importance. This study assessed the impact of various digested food items on oxidative stress, inflammation, and DNA/RNA damage in human gut epithelial cells. Differentiated Caco-2 cells were exposed to food items and their combinations (n = 22) selected from a previous study, including sausage, white chocolate, soda, coffee, orange juice, and curcumin. Following stimulation with TNF-α/IFN-1β/LPS and H2O2 for 4 h, the cells were exposed to digested food items or appropriate controls (empty digesta and medium) for a further 16 h. Cell viability, antioxidant capacity (ABTS, FRAP), IL-6, IL-8, F2-isoprostanes, lipid peroxidation (MDA), and DNA/RNA oxidative damage were assessed (3 independent triplicates). The ABTS assay revealed that cells treated with "white chocolate" and "sausage + coffee" exhibited significantly reduced antioxidant capacity compared to stimulated control cells (ABTS = 52.3%, 54.8%, respectively, p < 0.05). Similar results were observed for FRAP (sausage = 34.9%; white chocolate + sausage = 35.1%). IL-6 levels increased in cells treated with "white chocolate + sausage" digesta (by 101%, p < 0.05). Moreover, MDA levels were significantly elevated in cells treated with digested "sausage" or sausage in combination with other food items. DNA/RNA oxidative damage was found to be higher in digesta containing sausage or white chocolate (up to 550%, p < 0.05) compared to stimulated control cells. This investigation provides insights into how different food items may affect gut health and underscores the complex interplay between food components and the epithelium at this critical interface of absorption.

Obesity under the moonlight of c-MYC

The moonlighting protein c-Myc is a master regulator of multiple biological processes including cell proliferation, differentiation, angiogenesis, apoptosis and metabolism. It is constitutively and aberrantly expressed in more than 70% of human cancers. Overwhelming evidence suggests that c-Myc dysregulation is involved in several inflammatory, autoimmune, metabolic and other non-cancerous diseases. In this review, we addressed the role of c-Myc in obesity. Obesity is a systemic disease, accompanied by multi-organ dysfunction apart from white adipose tissue (WAT), such as the liver, the pancreas, and the intestine. c-Myc plays a big diversity of functions regulating cellular proliferation, the maturation of progenitor cells, fatty acids (FAs) metabolism, and extracellular matrix (ECM) remodeling. Moreover, c-Myc drives the expression of a wide range of metabolic genes, modulates the inflammatory response, induces insulin resistance (IR), and contributes to the regulation of intestinal dysbiosis. Altogether, c-Myc is an interesting diagnostic tool and/or therapeutic target in order to mitigate obesity and its consequences.

Gut microbiota bridges dietary nutrients and host immunity

Dietary nutrients and the gut microbiota are increasingly recognized to cross-regulate and entrain each other, and thus affect host health and immune-mediated diseases. Here, we systematically review the current understanding linking dietary nutrients to gut microbiota-host immune interactions, emphasizing how this axis might influence host immunity in health and diseases. Of relevance, we highlight that the implications of gut microbiota-targeted dietary intervention could be harnessed in orchestrating a spectrum of immune-associated diseases.

In vitro and in silico cholinesterase inhibitory potential of metabolites from Laurencia snackeyi (Weber-van Bosse) M. Masuda

Alzheimer's disease (AD) is a neurodegenerative disease that causes deterioration in intelligence and psychological activities. Yet, till today, no cure is available for AD. The marine environment is an important sink of bioactive compounds with neuroprotective potential with reduced adverse effects. Recently, we collected the red algae Laurencia snackeyi from Terumbu Island, Malaysia which is known to be rich in halogenated metabolites making it the most sought-after red algae for pharmaceutical studies. The red alga was identified based on basic morphological characteristics, microscopic observation and chemical data from literature. The purplish-brown algae was confirmed a new record. In Malaysia, this species is poorly documented in Peninsular Malaysia as compared to its eastern continent Borneo. Thus, this study intended to investigate the diversity of secondary metabolites present in the alga and its cholinesterase inhibiting potential for AD. The extract inhibited both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with IC50 values of  14.45 ± 0.34 μ g mL-1 and 39.59 ± 0.24 μ g mL-1, respectively. Subsequently, we isolated the synderanes, palisadin A (1), aplysistatin (2) and 5-acetoxypalisadin B (3) that was not exhibit potential. Mass spectrometry analysis detected at total of 33 additional metabolites. The computational aided molecular docking using the AChE and BChE receptors on all metabolites shortlisted 5,8,11,14-eicosatetraynoic acid (31) and 15-hydroxy-1-[2-(hydroxymethyl)-1-piperidinyl]prost-13-ene-1,9-dione (42) with best inhibitory properties, respectively with the lowest optimal combination of S-score and RMSD values. This study shows the unexplored potential of marine natural resources, however, obtaining sufficient biomass for detailed investigation is an uphill task. Regardless, there is a lot of potential for future prospects with a wide range of marine natural resources to study and the incorporation of synthetic chemistry, in vivo studies in experimental design.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03725-6.

Understanding the Anti-Obesity Potential of an Avocado Oil-Rich Cheese through an In Vitro Co-Culture Intestine Cell Model

Nowadays, with consumers' requirements shifting towards more natural solutions and the advent of nutraceutical-based approaches, new alternatives for obesity management are being developed. This work aimed to show, for the first time, the potential of avocado oil-fortified cheese as a viable foodstuff for obesity management through complex in vitro cellular models. The results showed that oleic and palmitic acids' permeability through the Caco-2/HT29-MTX membrane peaked at the 2h mark, with the highest apparent permeability being registered for oleic acid (0.14 cm/s). Additionally, the permeated compounds were capable of modulating the metabolism of adipocytes present in the basal compartment, significantly reducing adipokine (leptin) and cytokine (MPC-1, IL-10, and TNF-α) production. The permeates (containing 3.30 µg/mL of palmitic acid and 2.16 µg/mL of oleic acid) also presented an overall anti-inflammatory activity upon Raw 264.7 macrophages, reducing IL-6 and TNF-α secretion. Despite in vivo assays being required, the data showed the potential of a functional dairy product as a valid food matrix to aid in obesity management.

The impact of common pharmaceutical excipients on the gut microbiota

INTRODUCTION

Increasing attention is being afforded to understanding the bidirectional relationships that exist between oral medications and the gut microbiota, in an attempt to optimize pharmacokinetic performance and mitigate unwanted side effects. While a wealth of research has investigated the direct impact of active pharmaceutical ingredients (APIs) on the gut microbiota, the interactions between inactive pharmaceutical ingredients (i.e. excipients) and the gut microbiota are commonly overlooked, despite excipients typically representing over 90% of the final dosage form.

AREAS COVERED

Known excipient-gut microbiota interactions for various classes of inactive pharmaceutical ingredients, including solubilizing agents, binders, fillers, sweeteners, and color additives, are reviewed in detail.

EXPERT OPINION

Clear evidence indicates that orally administered pharmaceutical excipients directly interact with gut microbes and can either positively or negatively impact gut microbiota diversity and composition. However, these relationships and mechanisms are commonly overlooked during drug formulation, despite the potential for excipient-microbiota interactions to alter drug pharmacokinetics and interfere with host metabolic health. The insights derived from this review will inform pharmaceutical scientists with the necessary design considerations for mitigating potential adverse pharmacomicrobiomic interactions when formulating oral dosage forms, ultimately providing clear avenues for improving therapeutic safety and efficacy.

Serum Saturated Fatty Acids including Very Long-Chain Saturated Fatty Acids and Colorectal Cancer Risk among Chinese Population

The association between circulating saturated fatty acids (SFAs) including very long-chain SFAs (VLCSFAs) and colorectal cancer (CRC) risk has not been clearly established. To investigate the association between serum SFAs and CRC risk in Chinese population, 680 CRC cases and 680 sex and age-matched (5-year interval) controls were recruited in our study. Serum levels of SFAs were detected by gas chromatography. Unconditional logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between serum SFAs and CRC risk. Results showed that total SFAs were positively associated with the risk of CRC (adjusted OR _{quartile 4 vs. 1} = 2.64, 95%CI: 1.47-4.74). However, VLCSFAs were inversely associated with CRC risk (adjusted OR _{quartile 4 vs. 1} = 0.51, 95%CI: 0.36-0.72). Specifically, lauric acid, myristic acid, palmitic acid, heptadecanoic acid, and arachidic acid were positively associated with CRC risk, while behenic acid and lignoceric acid were inversely associated with CRC risk. This study indicates that higher levels of total serum SFAs and lower levels of serum VLCSFAs were associated with an increased risk of CRC in Chinese population. To reduce the risk of CRC, we recommend reducing the intake of foods containing palmitic acid and heptadecanoic acid such as animal products and dairy products, and moderately increasing the intake of foods containing VLCSFAs such as peanuts and canola oil.

Alteration of gut microbiota in wild-borne long-tailed macaques after 1-year being housed in hygienic captivity

The wild-born long-tailed macaques (Macaca fascicularis) were recently recruited and used as breeders for the National Primate Research Center of Thailand, Chulalongkorn University (NPRCT-CU), and changes in their in-depth gut microbiota profiles were investigated. The Oxford Nanopore Technology (ONT) was used to explore full-length 16S rDNA sequences of gut microbiota in animals once captured in their natural habitat and 1-year following translocation and housing in a hygienic environment at NPRCT-CU. Our findings show that the gut microbiota of macaques after 1 year of hygienic housing and programmed diets feeding was altered and reshaped. The prevalent gut bacteria such as Prevotella copri and Faecalibacterium prausnitzii were enriched after translocation, causing the lower alpha diversity. The correlation analysis revealed that Prevotella copri, Phascolarctobacterium succinatutens, and Prevotella stercorea, showed a positive correlation with each other. Significantly enriched pathways in the macaques after translocation included biosynthesis of essential amino acids, fatty acids, polyamine and butanoate. The effects of microbiota change could help macaques to harvest the energy from programmed diets and adapt their gut metabolism. The novel probiotics and microbiota engineering approach could be further developed based on the current findings and should be helpful for captive animal health care management.

Inflammatory crosstalk between saturated fatty acids and gut microbiota-white adipose tissue axis

PURPOSE

High-fat diets have different metabolic responses via gut dysbiosis. In this review, we discuss the complex interaction between the intake of long- and medium-chain saturated fatty acids (SFAs), gut microbiota, and white adipose tissue (WAT) dysfunction, particularly focusing on the type of fat.

RESULTS

The evidence for the impact of dietary SFAs on the gut microbiota-WAT axis has been mostly derived from in vitro and animal models, but there is now also evidence emerging from human studies. Most current reports show that, in response to high long- and medium-chain SFA diets, WAT functions are altered and can be modulated from microbial metabolites in several manners; and it appears to be also modified under conditions of obesity. SFAs overconsumption can reduce bacterial content and disrupt the gut environment. Both long- and medium-chain SFAs may contribute to proinflammatory cytokines release and TLR4 cascade signaling, either by regulation of endotoxemia markers or myristoylated protein. Palmitic and stearic acids have pathological effects on the intestinal epithelium, microbes, and inflammatory and lipogenic WAT profiles. While myristic and lauric acids display somewhat controversial outcomes, from probiotic effects and contribution to weight loss to cardiometabolic alterations from WAT inflammation.

CONCLUSION

Identifying an interference of distinct types of SFA in the binomial gut microbiota-WAT may elucidate essential mechanisms of metabolic endotoxemia, which may be the key to triggering obesity, innovating the therapeutic tools for this disease.

The Human Milk Metabolome: A Scoping Literature Review

BACKGROUND

Human milk is a complex source of nutrition and other bioactives that protects infants from disease, holding a lifetime of beneficial effects. The field of metabolomics provides a robust platform through which we can better understand human milk at a level rarely examined.

RESEARCH AIM

To Identify, describe, synthesize, and critically analyze the literature within the past 5 years related to the human milk metabolome.

METHODS

We conducted a scoping literature review and quality analysis of the recent science reflecting untargeted metabolomic approaches to examining human milk. We searched six databases using the terms "breast milk," "metabolome," "metabolite," and "human milk," Out of more than 1,069 abstracts, we screened and identified 22 articles that met our inclusion criteria.

RESULTS

We extracted data related to the study author, geographic location, research design, analyses, platform used, and results. We also extracted data related to human milk research activities, including collection protocol, infant/maternal considerations, and time. Selected studies focused on a variety of phenotypes, including maternal and infant disease. Investigators used varying approaches to evaluate the metabolome, and differing milk collection protocols were observed.

CONCLUSION

The human milk metabolome is informed by many factors-which may contribute to infant health outcomes-that have resulted in disparate milk metabolomic profiles. Standardized milk collection and storage procedures should be implemented to minimize degradation. Investigators may use our findings to develop research questions that test a targeted metabolomic approach.

Low-fat dairy consumption improves intestinal immune function more than high-fat dairy in a diet-induced swine model of insulin resistance

PURPOSE

To understand the effects of consuming high-fat and low-fat dairy products on postprandial cardiometabolic risk factors and intestinal immune function, we used an established low birthweight (LBW) swine model of diet-induced insulin resistance.

METHODS

LBW piglets were randomized to consume one of the 3 experimental high fat diets and were fed for a total of 7 weeks: (1) Control high fat (LBW-CHF), (2) CHF diet supplemented with 3 servings of high-fat dairy (LBW-HFDairy) and (3) CHF diet supplemented with 3 servings of low-fat dairy (LBW-LFDairy). As comparison groups, normal birthweight (NBW) piglets were fed a CHF (NBW-CHF) or standard pig grower diet (NBW-Chow). At 11 weeks of age, all piglets underwent an established modified oral glucose and fat tolerance test. At 12 weeks of age, piglets were euthanized and ex vivo cytokine production by cells isolated from mesenteric lymph node (MLN) stimulated with mitogens was assessed.

RESULTS

Dairy consumption did not modulate postprandial plasma lipid, inflammatory markers and glucose concentrations. A lower production of IL-2 and TNF-α after pokeweed mitogen (PWM) stimulation was observed in LBW-CHF vs NBW-Chow (P < 0.05), suggesting impaired MLN T cell function. While feeding high-fat dairy had minimal effects, feeding low-fat dairy significantly improved the production of IL-2 and TNF-α after PWM stimulation (P < 0.05).

CONCLUSIONS

Irrespective of fat content, dairy had a neutral effect on postprandial cardiometabolic risk factors. Low-fat dairy products improved intestinal T cell function to a greater extent than high-fat dairy in this swine model of obesity and insulin resistance.

Type I Diabetes Pathoetiology and Pathophysiology: Roles of the Gut Microbiome, Pancreatic Cellular Interactions, and the 'Bystander' Activation of Memory CD8+ T Cells

Type 1 diabetes mellitus (T1DM) arises from the failure of pancreatic β-cells to produce adequate insulin, usually as a consequence of extensive pancreatic β-cell destruction. T1DM is classed as an immune-mediated condition. However, the processes that drive pancreatic β-cell apoptosis remain to be determined, resulting in a failure to prevent ongoing cellular destruction. Alteration in mitochondrial function is clearly the major pathophysiological process underpinning pancreatic β-cell loss in T1DM. As with many medical conditions, there is a growing interest in T1DM as to the role of the gut microbiome, including the interactions of gut bacteria with Candida albicans fungal infection. Gut dysbiosis and gut permeability are intimately associated with raised levels of circulating lipopolysaccharide and suppressed butyrate levels, which can act to dysregulate immune responses and systemic mitochondrial function. This manuscript reviews broad bodies of data on T1DM pathophysiology, highlighting the importance of alterations in the mitochondrial melatonergic pathway of pancreatic β-cells in driving mitochondrial dysfunction. The suppression of mitochondrial melatonin makes pancreatic β-cells susceptible to oxidative stress and dysfunctional mitophagy, partly mediated by the loss of melatonin's induction of PTEN-induced kinase 1 (PINK1), thereby suppressing mitophagy and increasing autoimmune associated major histocompatibility complex (MHC)-1. The immediate precursor to melatonin, N-acetylserotonin (NAS), is a brain-derived neurotrophic factor (BDNF) mimic, via the activation of the BDNF receptor, TrkB. As both the full-length and truncated TrkB play powerful roles in pancreatic β-cell function and survival, NAS is another important aspect of the melatonergic pathway relevant to pancreatic β-cell destruction in T1DM. The incorporation of the mitochondrial melatonergic pathway in T1DM pathophysiology integrates wide bodies of previously disparate data on pancreatic intercellular processes. The suppression of Akkermansia muciniphila, Lactobacillus johnsonii, butyrate, and the shikimate pathway-including by bacteriophages-contributes to not only pancreatic β-cell apoptosis, but also to the bystander activation of CD8⁺ T cells, which increases their effector function and prevents their deselection in the thymus. The gut microbiome is therefore a significant determinant of the mitochondrial dysfunction driving pancreatic β-cell loss as well as 'autoimmune' effects derived from cytotoxic CD8⁺ T cells. This has significant future research and treatment implications.

Polygonum tinctorium leaf extract ameliorates high-fat diet-induced intestinal epithelial damage in mice

Dietary fat strongly influences the intestinal mucosal barrier, which protects against invading pathogenic bacteria. A high-fat diet (HFD) compromises the integrity of epithelial tight junctions (TJs) and reduces mucin production, leading to intestinal barrier disruption and metabolic endotoxemia. It has been shown that the active constituents of indigo plants can protect against intestinal inflammation; however, their protective role in HFD-induced intestinal epithelial damage remains unknown. The present study aimed to investigate the effects of Polygonum tinctorium leaf extract (indigo Ex) on HFD-induced intestinal damage in mice. Male C57BL6/J mice were fed a HFD and injected intraperitoneally with either indigo Ex or phosphate-buffered saline (PBS) for 4 weeks. The expression levels of TJ proteins, zonula occludens-1 and Claudin-1, were analyzed by immunofluorescence staining and western blotting. The colon mRNA expression levels of tumor necrosis factor-α, interleukin (IL)-12p40, IL-10 and IL-22 were measured by reverse transcription-quantitative PCR. The results revealed that indigo Ex administration attenuated the HFD-induced shortening of the colon. Colon crypt length was shown to be significantly greater in the indigo Ex-treated group mice compared with that in the PBS-treated group mice. Moreover, indigo Ex administration increased the number of goblet cells, and ameliorated the redistribution of TJ proteins. Notably, indigo Ex significantly increased the colon mRNA expression levels of IL-10. Indigo Ex displayed little effect on the gut microbial composition of HFD-fed mice. Taken together, these results suggested that indigo Ex may protect against HFD-induced epithelial damage. The leaves of indigo plants contain promising natural therapeutic compounds that could be used to treat obesity-associated intestinal damage and metabolic inflammation.

Metabolomics Study of Shaoyao Plants Decoction on the Proximal and Distal Colon in Mice with Dextran Sulfate Sodium-Induced Colitis by UPLC-Q-TOF-MS

Purpose

Shaoyao decoction (SYD) is a traditional Chinese medicine used to treat ulcerative colitis (UC). The exact mechanism of action of SYD in UC treatment is still unclear. Here, we examined the therapeutic effects of SYD in mice with dextran sulfate sodium (DSS)-induced colitis and explored the underlying mechanism.

Methods

The experimental group was divided into normal control, UC, and SYD treatment groups. The UC model of C57BL/6 mice was induced using 3% (w/v) DSS for 7 days. SYD was orally administered for 7 days. The proximal and distal colonic metabolic profiles were detected using quadrupole-time-of-flight mass spectrometry-based untargeted metabolomics.

Results

SYD significantly increased weight, reduced disease activity index scores, and ameliorated colon length shortening and pathological damage in mice. In the distal colon, SYD increased the abundance of phosphatidic acid and lysophosphatidylethanolamine and decreased the abundance of lactosylceramide, erythrodiol 3-palmitate, and lysophosphatidylcholine. In the proximal colon, SYD increased the abundance of palmitic acid, cyclonormammein, monoacylglyceride, 13S-hydroxyoctadecadienoic acid, and ceanothine C and decreased the abundance of tetracosahexaenoic acid, phosphatidylserine, and diglyceride.

Conclusion

Our findings revealed that SYD could alleviate UC by regulating metabolic dysfunction, which provides a reference for further studies on SYD.

The metabolic nature of inflammatory bowel diseases

Crohn's disease and ulcerative colitis, phenotypically comprising a spectrum of inflammatory bowel diseases (IBDs), spread globally during the westernization of lifestyle and dietary habits over the past few decades. Here, we review experimental and clinical evidence for the metabolic nature of gut inflammation in IBD and delineate distinct parallels to the inflammatory state in metabolic diseases. Experimental evidence indicates that excessive intake of specific macronutrients in a Western diet fuels an inflammatory response in the gut by exploiting sensors of innate immunity and perturbation of gut microbial metabolism. Genetic IBD risk partly affects metabolism and stress signalling of innate immunity, and immunometabolism controls susceptibility to gut inflammation. Epidemiological and clinical studies indicate that specific nutrients in the Western diet pose a risk for the development of IBD and a poor disease course. Translational studies in IBD indicate perturbation of energy metabolism in immune cells and perturbation of gut microbial metabolism, which can be shaped by diet. In turn, dietary restriction by exclusive enteral nutrition induces remission in patients with IBD. Collectively, these studies support a metabolic underpinning of gut inflammation in IBD as described for metabolic inflammation in obesity and related disorders.

Attenuation of Palmitic Acid-Induced Intestinal Epithelial Barrier Dysfunction by 6-Shogaol in Caco-2 Cells: The Role of MiR-216a-5p/TLR4/NF-κB Axis

Palmitic acid (PA) can lead to intestinal epithelial barrier dysfunction. In this study, the protective effects and working mechanisms of 6-shogaol against PA-induced intestinal barrier dysfunction were investigated in human intestinal epithelial Caco-2 cells. Transepithelial electrical resistance (TEER), paracellular flux, qRT-PCR, immunofluorescence, and Western blot experiments showed that the 24-h treatment with 400 μM PA damaged intestinal barrier integrity, as evidenced by a reduction of 48% in the TEER value, a 4.1-fold increase in the flux of fluorescein isothiocyanate-dextran 4000 (FD-4), and decreases in the mRNA and protein expression of tight junction (TJ)-associated proteins (claudin-1, occludin, and ZO-1), compared with the control. The PA treatment significantly (p < 0.05) increased the levels of pro-inflammatory cytokines (interleukin (IL)-6, IL-1β, and tumor necrosis factor-alpha (TNF-α)) in Caco-2 cells due to the upregulation of toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), phosphorylated nuclear factor kappa-B (NF-κB) proteins, and downregulation of miR-216a-5p (which directly targeted TLR4). Co-treatment with PA and 6-shogaol (2.5 μM) significantly (p < 0.05) attenuated PA-induced changes through regulation of TJs via the miR-216a-5p/TLR4/NF-κB signaling pathway. This study provides insights into the functions and working mechanisms of 6-shogaol as a promising food-derived agent against PA-induced intestinal epithelial barrier dysfunction.

Palmitic acid induces intestinal lipid metabolism disorder, endoplasmic reticulum stress and inflammation by affecting phosphatidylethanolamine content in large yellow croaker Larimichthys crocea

In the 21^st century, intestinal homeostatic imbalance has emerged as a growing health challenge worldwide. Accumulating evidence reveals that excessive intake of saturated fatty acid (SFA) induces intestinal homeostatic imbalance. However, the potential molecular mechanism is still unclear. In the present study, we found that palm oil or palmitic acid (PA) treatment disturbed lipid metabolism homeostasis and triggered endoplasmic reticulum (ER) stress and inflammation in the intestine or intestinal cells of large yellow croaker (Larimichthys crocea). Interestingly, PA treatment significantly decreased phosphatidylethanolamine (PE) content in the intestinal cells. PE supplementation decreased triglyceride content in the intestinal cells induced by PA treatment by inhibiting fatty acid uptake and lipogenesis. PE supplementation suppressed ER stress. Meanwhile, PE supplementation alleviated inflammatory response through p38 MAPK-p65 pathway, reducing the damage of intestinal cells caused by PA treatment to some extent. Our work revealed that intestinal homeostatic imbalance caused by PA treatment was partly due to the decrease of PE content. PE consumption might be a nutritional strategy to regulate intestinal homeostasis in fish and even human beings.

Probiotics or synbiotics addition to sows’ diets alters colonic microbiome composition and metabolome profiles of offspring pigs

Little information exists about the effects of maternal probiotics and synbiotics addition on the gut microbiome and metabolome of offspring. The present study evaluated the effects of probiotics or synbiotics addition to sows’ diets on colonic microbiota and their metabolites in offspring using 16S rRNA gene sequencing and metabolome strategy. A total of 64 pregnant Bama mini-pigs were randomly divided into control, antibiotic, probiotics, and synbiotics groups and fed the corresponding experimental diets during pregnancy and lactation. After weaning, two piglets per litter and eight piglets per group were selected and fed a basal diet. The β-diversity analysis showed that the colonic microbiota of offspring had a clear distinction among the four groups at 65 days of age. Maternal probiotics addition increased the Actinobacteria abundance at 65 days of age and Tenericutes and Firmicutes abundances at 95 days of age of offspring compared with the other three groups, whereas maternal antibiotic addition increased Spirochaetes and Proteobacteria abundances at 95 days of age of offspring compared with the other three groups. Metabolomic analysis showed that colonic metabolites were different between the groups, regardless of the days of age. Furthermore, both PICRUSt2 and enrichment analysis of metabolic pathways showed that maternal probiotics and synbiotics addition affected metabolism of carbohydrate, amino acid, cofactors and vitamins in the colonic microbiota. Compared with the control group, the colonic concentration of indole decreased and skatole increased in the probiotics group, whereas indole increased and skatole decreased in the synbiotics group. Maternal probiotics addition increased the colonic concentrations of acetate and butyrate at 65 and 125 days of age, whereas probiotics and synbiotics addition decreased short-chain fatty acids concentrations at 95 days of age. In addition, the colonic concentrations of putrescine, cadaverine, 1,7-heptanediamine, and spermidine were increased in the antibiotic, probiotics, and synbiotics groups compared with the control group at 95 days of age. The correlation analysis showed that Gemmiger, Roseburia, and Faecalibacterium abundances were positively correlated with acetate, propionate, and butyrate concentrations; Gemmiger, Blautia, and Faecalibacterium were positively correlated with putrescine and spermidine; and Faecalibacterium, Blautia, Clostridium, and Streptococcus were positively correlated with (R)-3-hydroxybutyric acid. Collectively, these findings suggest that probiotics and synbiotics addition to sows’ diets exerts effects on offspring pigs by altering gut microbiota composition and their metabolites. The potential beneficial effect on gut health is discussed.

Dietary Component-Induced Inflammation and Its Amelioration by Prebiotics, Probiotics, and Synbiotics

A balanced diet with many dietary components maintains immune homeostasis directly by interacting with innate and adaptive immune components or indirectly through gut microbiota and their metabolites. Dietary components may inhibit pro-inflammatory mediators and promote anti-inflammatory functions or vice versa. Western diets with imbalanced dietary components skew the immune balance toward pro-inflammation and induce intestinal inflammation, consequently leading to many intestinal and systemic inflammatory diseases like ulcerative colitis, Crohn's disease, irritable bowel syndrome, cardiovascular problems, obesity, and diabetes. The dietary component-induced inflammation is usually chronic in nature and frequently caused or accompanied by alterations in gut microbiota. Therefore, microbiome-targeted therapies such as probiotics, prebiotics and synbiotics hold great potentials to amend immune dysregulation and gut dysbiosis, preventing and treating intestinal and systemic inflammatory diseases. Probiotics, prebiotics and synbioitcs are progressively being added to foods and beverages, with claims of health benefits. However, the underlining mechanisms of these interventions for preventing and treating dietary component-induced inflammation are still not very clear. In addition, possibly ineffective or negative consequences of some probiotics, prebiotics and synbiotics call for stringent testing and regulation. Here, we will first briefly review inflammation, in terms of its types and the relationship between different dietary components and immune responses. Then, we focus on current knowledge about the direct and indirect effects of probiotics, prebiotics and synbiotics on intestinal and systemic inflammation. Understanding how probiotics, prebiotics and synbiotics modulate the immune system and gut microbiota will improve our strategies for preventing and treating dietary component-induced intestinal inflammation and inflammatory diseases.

Exploring the Links between Obesity and Psoriasis: A Comprehensive Review

Obesity is a major public health issue worldwide since it is associated with the development of chronic comorbidities such as type 2 diabetes, dyslipidemias, atherosclerosis, some cancer forms and skin diseases, including psoriasis. Scientific evidence has indicated that the possible link between obesity and psoriasis may be multifactorial, highlighting dietary habits, lifestyle, certain genetic factors and the microbiome as leading factors in the progress of both pathologies because they are associated with a chronic pro-inflammatory state. Thus, inflammation management in obesity is a plausible target for psoriasis, not only because of the sick adipose tissue secretome profile but also due to the relationship of obesity with the rest of the immune derangements associated with psoriasis initiation and maintenance. Hence, this review will provide a general and molecular overview of the relationship between both pathologies and present recent therapeutic advances in treating this problem.

Is type 2 diabetes mellitus another intercellular junction-related disorder?

Type 2 diabetes mellitus (T2D) is nowadays a worldwide epidemic and has become a major challenge for health systems around the world. It is a multifactorial disorder, characterized by a chronic state of hyperglycemia caused by defects in the production as well as in the peripheral action of insulin. This minireview highlights the experimental and clinical evidence that supports the novel idea that intercellular junctions (IJs)-mediated cell-cell contacts play a role in the pathogenesis of T2D. It focuses on IJs repercussion for endocrine pancreas, intestinal barrier, and kidney dysfunctions that contribute to the onset and evolution of this metabolic disorder.

Enteroendocrine System and Gut Barrier in Metabolic Disorders

With the continuous rise in the worldwide prevalence of obesity and type 2 diabetes, developing therapies regulating body weight and glycemia has become a matter of great concern. Among the current treatments, evidence now shows that the use of intestinal hormone analogs (e.g., GLP1 analogs and others) helps to control glycemia and reduces body weight. Indeed, intestinal endocrine cells produce a large variety of hormones regulating metabolism, including appetite, digestion, and glucose homeostasis. Herein, we discuss how the enteroendocrine system is affected by local environmental and metabolic signals. These signals include those arising from unbalanced diet, gut microbiota, and the host metabolic organs and their complex cross-talk with the intestinal barrier integrity.

Metabolomics reveals the impact of saturation of dietary lipids on aging and longevity of C. elegans

Saturation differences in dietary lipids modify their digestive and absorption profiles, endpoints that may influence the nutrition and health. This study tests the hypothesis that dietary with elevated unsaturated fats...

The Role of Dietary Fats in the Development and Prevention of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a significant cause of mortality and morbidity in preterm infants. The pathogenesis of NEC is not completely understood; however, intestinal immaturity and excessive immunoreactivity of intestinal mucosa to intraluminal microbes and nutrients appear to have critical roles. Dietary fats are not only the main source of energy for preterm infants, but also exert potent effects on intestinal development, intestinal microbial colonization, immune function, and inflammatory response. Preterm infants have a relatively low capacity to digest and absorb triglyceride fat. Fat may thereby accumulate in the ileum and contribute to the development of NEC by inducing oxidative stress and inflammation. Some fat components, such as long-chain polyunsaturated fatty acids (LC-PUFAs), also exert immunomodulatory roles during the early postnatal period when the immune system is rapidly developing. LC-PUFAs may have the ability to modulate the inflammatory process of NEC, particularly when the balance between n3 and n6 LC-PUFAs derivatives is maintained. Supplementation with n3 LC-PUFAs alone may have limited effect on NEC prevention. In this review, we describe how various fatty acids play different roles in the pathogenesis of NEC in preterm infants.

Gossip in the gut: Quorum sensing, a new player in the host-microbiota interactions

Bacteria are known to communicate with each other and regulate their activities in social networks by secreting and sensing signaling molecules called autoinducers, a process known as quorum sensing (QS). This is a growing area of research in which we are expanding our understanding of how bacteria collectively modify their behavior but are also involved in the crosstalk between the host and gut microbiome. This is particularly relevant in the case of pathologies associated with dysbiosis or disorders of the intestinal ecosystem. This review will examine the different QS systems and the evidence for their presence in the intestinal ecosystem. We will also provide clues on the role of QS molecules that may exert, directly or indirectly through their bacterial gossip, an influence on intestinal epithelial barrier function, intestinal inflammation, and intestinal carcinogenesis. This review aims to provide evidence on the role of QS molecules in gut physiology and the potential shared by this new player. Better understanding the impact of intestinal bacterial social networks and ultimately developing new therapeutic strategies to control intestinal disorders remains a challenge that needs to be addressed in the future.

High-Fat Diet Induces Disruption of the Tight Junction-Mediated Paracellular Barrier in the Proximal Small Intestine Before the Onset of Type 2 Diabetes and Endotoxemia

BACKGROUND/AIM

A link between an impaired intestinal barrier, endotoxemia, and the pathogenesis of metabolic diseases, such as type 2 diabetes mellitus (T2DM), has been proposed. In previous work, we have demonstrated that the tight junction (TJ)-mediated intestinal barrier in ileum/colon was marginally changed in prediabetic mice; therefore, it does not seem to mainly contribute to the T2DM onset. In this study, the TJ-mediated epithelial barrier in the duodenum and jejunum was evaluated in mice during the development of type 2 prediabetes.

METHODS/RESULTS

HF diet induced prediabetes after 60 days associated with a significant rise in intestinal permeability to the small-sized marker Lucifer yellow in these mice, with no histological signs of mucosal inflammation or rupture of the proximal intestine epithelium. As revealed by immunofluorescence, TJ proteins, such as claudins-1, -2, -3, and ZO-1, showed a significant decrease in junctional content in duodenum and jejunum epithelia, already after 15 days of treatment, suggesting a rearrangement of the TJ structure. However, no significant change in total cell content of these proteins was observed in intestinal epithelium homogenates, as assessed by immunoblotting. Despite the changes in intestinal permeability and TJ structure, the prediabetic mice showed similar LPS, zonulin, and TNF-α levels in plasma or adipose tissue, and in intestinal segments as compared to the controls.

CONCLUSION

Disruption of the TJ-mediated paracellular barrier in the duodenum and jejunum is an early event in prediabetes development, which occurs in the absence of detectable endotoxemia/inflammation and may contribute to the HF diet-induced increase in intestinal permeability.

The Liquid Diet Composition Affects the Fecal Bacterial Community in Pre-weaning Dairy Calves

Feeding a liquid diet to the newborn calf has considerable implications for developing the intestinal microbiota, as its composition can shift the population to a highly adapted microbiota. The present work evaluated 15 Holstein calves individually housed and fed one of the three liquid diets: I – whole milk (n = 5), II – milk replacer (22.9% CP; 16.2% fat; diluted to 14% solids; n = 5) and III – acidified whole milk to pH 4.5 with formic acid (n = 5). All animals received 6 L of liquid diet, divided into two meals, being weaned at week 8 of life. Calves also had free access to water and starter concentrate. After weaning, all calves were grouped on pasture, fed with starter concentrate, and hay ad libitum. The fecal samples were collected at birth (0) and at weeks 1, 2, 4, 8, and 10 of life. The bacterial community was assessed the through sequencing of the V3-V4 region of the 16S rRNA gene on the Illumina MiSeq platform and analyzed using the DADA2 pipeline. Diversity indices were not affected by the liquid diets, but by age (P &lt; 0.001) with weeks 1 and 2 presenting lower diversity, evenness, and richness values. The bacterial community structure was affected by diet, age, and the interaction of these factors (P &lt; 0.01). Twenty-eight bacterial phyla were identified in the fecal samples, and the most predominant phyla were Firmicutes (42.35%), Bacteroidota (39.37%), and Proteobacteria (9.36%). The most prevalent genera were Bacteroides (10.71%), Lactobacillus (8.11%), Alloprevotella (6.20%). Over the weeks, different genera were predominant, with some showing significant differences among treatments. The different liquid diets altered the fecal bacterial community during the pre-weaning period. However, differences in the initial colonization due to different liquid diets are alleviated after weaning, when animals share a common environment and solid diet composition.

Dietary intake and plasma phospholipid concentrations of saturated, monounsaturated and trans fatty acids and colorectal cancer risk in the European Prospective Investigation into Cancer and Nutrition cohort

Epidemiologic studies examining the association between specific fatty acids and colorectal cancer (CRC) risk are inconclusive. We investigated the association between dietary estimates and plasma levels of individual and total saturated (SFA), monounsaturated (MUFA), industrial-processed trans (iTFA), and ruminant-sourced trans (rTFA) fatty acids, and CRC risk in the European Prospective Investigation into Cancer and Nutrition (EPIC). Baseline fatty acid intakes were estimated in 450 112 participants (6162 developed CRC, median follow-up = 15 years). In a nested case-control study, plasma phospholipid fatty acids were determined by gas chromatography in 433 colon cancer cases and 433 matched controls. Multivariable-adjusted hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs) were computed using Cox and conditional logistic regression, respectively. Dietary total SFA (highest vs lowest quintile, HRQ5vsQ1  = 0.80; 95%CI:0.69-0.92), myristic acid (HRQ5vsQ1  = 0.83, 95%CI:0.74-0.93) and palmitic acid (HRQ5vsQ1  = 0.81, 95%CI:0.70-0.93) were inversely associated with CRC risk. Plasma myristic acid was also inversely associated with colon cancer risk (highest vs lowest quartile, ORQ4vsQ1  = 0.51; 95%CI:0.32-0.83), whereas a borderline positive association was found for plasma stearic acid (ORQ4vsQ1  = 1.63; 95%CI:1.00-2.64). Dietary total MUFA was inversely associated with colon cancer (per 1-SD increment, HR1-SD  = 0.92, 95%CI: 0.85-0.98), but not rectal cancer (HR1-SD  = 1.04, 95%CI:0.95-1.15, Pheterogeneity  = 0.027). Dietary iTFA, and particularly elaidic acid, was positively associated with rectal cancer (HR1-SD  = 1.07, 95%CI:1.02-1.13). Our results suggest that total and individual saturated fatty acids and fatty acids of industrial origin may be relevant to the aetiology of CRC. Both dietary and plasma myristic acid levels were inversely associated with colon cancer risk, which warrants further investigation.

Protective effects of Poria cocos and its components against cisplatin-induced intestinal injury

ETHNOPHARMACOLOGICAL RELEVANCE

Poria cocos (Schw.) Wolf (Poria) is a well-known traditional medicinal fungus. It has been considered to possess spleen-invigorating (Jianpi) effects in traditional Chinese medicine, and is used clinically to treat spleen deficiency (Pixu) with symptoms of intestinal disorders such as diarrhea, indigestion, mucositis and weight loss.

THE AIM OF THIS STUDY

To investigate the protective effects of Poria and its three component fractions (Water-soluble polysaccharides, WP; alkali-soluble polysaccharides, AP; triterpene acids, TA) on cisplatin-induced intestinal injury and explore the underlying mechanisms.

MATERIALS AND METHODS

C57BL/6 mice were treated with Poria powder (PP), WP, AP and TA by oral gavage respectively for 13 days, and intraperitoneally injected with 10 mg/kg of cisplatin on day 10 to conduct a cisplatin-induced intestinal injury model. Pathological changes of ileum and colon were examined using H&E staining. The composition of gut microbiota and the alteration of host metabolites were characterized by 16S rDNA amplicon sequencing and UPLC-QTOF-MS/MS based untargeted metabolomics analysis.

RESULTS

PP and WP attenuated the cisplatin-induced ileum and colon injury, and WP alleviated the weight loss and reversed the elevation of IL-2, IL-6 in serum. Both PP and WP could mitigate cisplatin-induced dysbiosis of gut microbiota, in particular PP and WP decreased the abundance of pathogenic bacteria including Proteobacteria, Cyanobacteria, Ruminococcaceae and Helicobacteraceae, while WP promoted the abundance of probiotics, such as Erysipelotrichaceae and Prevotellaceae. Moreover, WP attenuated the cisplatin-induced alteration of metabolic profiles. The levels of potential biomarkers, including xanthine, L-tyrosine, uridine, hypoxanthine, butyrylcarnitine, lysoPC (18:0), linoleic acid, (R)-3-hydroxybutyric acid, D-ribose, thiamine monophosphate, indolelactic acid and plamitic acid, showed significant correlations with intestinal flora.

CONCLUSIONS

PP and WP possess protective effects against cisplatin-induced intestinal injury via potentially regulating the gut microbiota and metabolic profiles.

Palmitic acid decreases cell migration by increasing RGS2 expression and decreasing SERCA expression

Palmitic acid, the main saturated fatty acid, is related with a wide range of metabolic disorders such as obesity, type 2 diabetes and heart disease. It is known that palmitic acid disturbs the expression of some important proteins for cell homeostasis such as SERCA and RGS2, however, the role of this lipid at the molecular level in these disorders is not completely elucidated. Thus, our aim was to determinate the effect of palmitic acid in a relevant cell process as it is cell migration and the participation of SERCA and RGS2 in this response. We found that palmitic acid reduces cell migration (determined by the Boyden chamber method) in an epithelial cell line (HEK293) and this effect is modulated by SERCA and RGS2 differential protein expression (measured by western blot). Also, overexpression of individual proteins, RGS2 and SERCA, produced a decrease and an increase on cell migration, respectively. Taken together, these data suggest that the expression of regulatory proteins is affected by high concentrations of saturated fatty acids and in consequence cell migration is diminished in epithelial cells.

Influence of different dietary oil consumption on nutrient malabsorption: An animal trial using Sprague Dawley rats

In the present study, the influences of five typical dietary oils (i.e., palm oil, PO; leaf lard oil, LO; rapeseed oil, RO; sunflower oil, SO; and linseed oil, LN) consumption on the nutrients malabsorption were studied using adult male Sprague Dawley rats. Results suggested that the C16:0 (24.534 ± 2.26% to 54.269 ± 1.28%) and C18:0 (18.433 ± 4.421% to 36.455 ± 3.316%) were the dominant fatty acids in fecal samples in different groups. After 6-week intervention by different dietary oils, the fecal moisture and water soluble protein content in PO group, the reducing sugar content in PO, LO, and RO groups were significantly increased compared with those in the control group (p < .05). Moreover, the Na, K, and Fe contents in LO group were all the highest among the all groups. These effects were probably due to the different fatty acids composition as illustrated in the correlation analysis results. The different effects were probably due to their distinct fatty acids composition as illustrated in the correlation analysis results. Results further indicated that the different dietary oils treatment, especially for the PO (SFAs, 43.17 ± 0.98%) and LO (SFAs, 36.44 ± 0.65%), increased the upstream inflammatory cytokine expression level in the Toll-like receptor signal pathway (i.e., TLR4 and MyD88), enhancing the gut permeability. This resulted in significant increase of serum lipopolysaccharide (LPS) levels (p < .05), which was closely connected with different metabolic diseases. The present study may provide basic understandings about different dietary oil enteral nutrition and their effects on gut health. PRACTICAL APPLICATIONS: The PO, LO, RO, SO, and LN are the five of the most typical dietary lipids in Asia countries, especially in China. They are the natural edible oils which are rich in C16:0, C18:0, C18:1, C18:2ω6, and C18:3ω3, respectively. The present study indicated that the different dietary lipid consumption may result in different dietary nutrients malabsorption, which are related with the dietary lipid fatty acid composition.

Nutritional Components in Western Diet Versus Mediterranean Diet at the Gut Microbiota-Immune System Interplay. Implications for Health and Disease

The most prevalent diseases of our time, non-communicable diseases (NCDs) (including obesity, type 2 diabetes, cardiovascular diseases and some types of cancer) are rising worldwide. All of them share the condition of an “inflammatory disorder”, with impaired immune functions frequently caused or accompanied by alterations in gut microbiota. These multifactorial maladies also have in common malnutrition related to physiopathology. In this context, diet is the greatest modulator of immune system–microbiota crosstalk, and much interest, and new challenges, are arising in the area of precision nutrition as a way towards treatment and prevention. It is a fact that the westernized diet (WD) is partly responsible for the increased prevalence of NCDs, negatively affecting both gut microbiota and the immune system. Conversely, other nutritional approaches, such as Mediterranean diet (MD), positively influence immune system and gut microbiota, and is proposed not only as a potential tool in the clinical management of different disease conditions, but also for prevention and health promotion globally. Thus, the purpose of this review is to determine the regulatory role of nutritional components of WD and MD in the gut microbiota and immune system interplay, in order to understand, and create awareness of, the influence of diet over both key components.

Rapid Evaluation of Intestinal Paracellular Permeability Using the Human Enterocytic-Like Caco-2/TC7 Cell Line

Paracellular permeability of the intestinal epithelium is a feature of the intestinal barrier, which plays an important role in the physiology of gut and the whole organism. Intestinal paracellular permeability is controlled by complex processes and is involved in the passage of ions and fluids (called pore pathway) and macromolecules (called leak pathway) through tight junctions, which seal the intercellular space. Impairment of intestinal paracellular permeability is associated with several diseases. The identification of a defect in intestinal paracellular permeability may help to understand the implication of gut barrier as a cause or a consequence in human pathology. Here we describe two complementary methods to evaluate alteration of paracellular permeability in cell culture, using the human intestinal cell line Caco-2 and its clone Caco-2/TC7.

Metabolism and Metabolic Disorders and the Microbiome: The Intestinal Microbiota Associated With Obesity, Lipid Metabolism, and Metabolic Health-Pathophysiology and Therapeutic Strategies

Changes in the intestinal microbiome have been associated with obesity and type 2 diabetes, in epidemiological studies and studies of the effects of fecal transfer in germ-free mice. We review the mechanisms by which alterations in the intestinal microbiome contribute to development of metabolic diseases, and recent advances, such as the effects of the microbiome on lipid metabolism. Strategies have been developed to modify the intestinal microbiome and reverse metabolic alterations, which might be used as therapies. We discuss approaches that have shown effects in mouse models of obesity and metabolic disorders, and how these might be translated to humans to improve metabolic health.

The intestinal quorum sensing 3-oxo-C12:2 Acyl homoserine lactone limits cytokine-induced tight junction disruption

The intestine is home to the largest microbiota community of the human body and strictly regulates its barrier function. Tight junctions (TJ) are major actors of the intestinal barrier, which is impaired in inflammatory bowel disease (IBD), along with an unbalanced microbiota composition. With the aim to identify new actors involved in host-microbiota interplay in IBD, we studied N-acyl homoserine lactones (AHL), molecules of the bacterial quorum sensing, which also impact the host. We previously identified in the gut a new and prominent AHL, 3-oxo-C12:2, which is lost in IBD. We investigated how 3-oxo-C12:2 impacts the intestinal barrier function, in comparison to 3-oxo-C12, a structurally close AHL produced by the opportunistic pathogen P. aeruginosa. Using Caco-2/TC7 cells as a model of polarized enterocytes, we compared the effects on paracellular permeability and TJ integrity of these two AHL, separately or combined with pro-inflammatory cytokines, Interferon-γ and Tumor Necrosis Factor-α, known to disrupt the barrier function during IBD. While 3-oxo-C12 increased paracellular permeability and decreased occludin and tricellulin signal at bicellular and tricellular TJ, respectively, 3-oxo-C12:2 modified neither permeability nor TJ integrity. Whereas 3-oxo-C12 potentiated the hyperpermeability induced by cytokines, 3-oxo-C12:2 attenuated their deleterious effects on occludin and tricellulin, and maintained their interaction with their partner ZO-1. In addition, 3-oxo-C12:2 limited the cytokine-induced ubiquitination of occludin and tricellulin, suggesting that this AHL prevented their endocytosis. In conclusion, the role of 3-oxo-C12:2 in maintaining TJ integrity under inflammatory conditions identifies this new AHL as a potential beneficial actor of host–microbiota interactions in IBD.

Palmitic Acid Affects Intestinal Epithelial Barrier Integrity and Permeability In Vitro

Palmitic acid (PA), a long-chain saturated fatty acid, might activate innate immune cells. PA plays a role in chronic liver disease, diabetes and Crohn’s disease, all of which are associated with impaired intestinal permeability. We investigated the effect of PA, at physiological postprandial intestinal concentrations, on gut epithelium as compared to lipopolysaccharide (LPS) and ethanol, using an in vitro gut model, the human intestinal epithelial cell line Caco-2 grown on transwell inserts. Cytotoxicity and oxidative stress were evaluated; epithelial barrier integrity was investigated by measuring the paracellular flux of fluorescein, and through RT-qPCR and immunofluorescence of tight junction (TJ) and adherens junction (AJ) mRNAs and proteins, respectively. In PA-exposed Caco-2 monolayers, cytotoxicity and oxidative stress were not detected. A significant increase in fluorescein flux was observed in PA-treated monolayers, after 90 min and up to 360 min, whereas with LPS and ethanol, this was only observed at later time-points. Gene expression and immunofluorescence analysis showed TJ and AJ alterations only in PA-exposed monolayers. In conclusion, PA affected intestinal permeability without inducing cytotoxicity or oxidative stress. This effect seemed to be faster and stronger than those with LPS and ethanol. Thus, we hypothesized that PA, besides having an immunomodulatory effect, might play a role in inflammatory and functional intestinal disorders in which the intestinal permeability is altered.

AhR activation defends gut barrier integrity against damage occurring in obesity

Objective

Obesity is characterized by systemic and low-grade tissue inflammation. In the intestine, alteration of the intestinal barrier and accumulation of inflammatory cells in the epithelium are important contributors of gut inflammation. Recent studies demonstrated the role of the aryl hydrocarbon receptor (AhR) in the maintenance of immune cells at mucosal barrier sites. A wide range of ligands of external and local origin can activate this receptor. We studied the causal relationship between AhR activation and gut inflammation in obesity.

Methods

Jejunum samples from subjects with normal weight and severe obesity were phenotyped according to T lymphocyte infiltration in the epithelium from lamina propria and assayed for the mRNA level of AhR target genes. The effect of an AhR agonist was studied in mice and Caco-2/TC7 cells. AhR target gene expression, permeability to small molecules and ions, and location of cell-cell junction proteins were recorded under conditions of altered intestinal permeability.

Results

We showed that a low AhR tone correlated with a high inflammatory score in the intestinal epithelium in severe human obesity. Moreover, AhR activation protected junctional complexes in the intestinal epithelium in mice challenged by an oral lipid load. AhR ligands prevented chemically induced damage to barrier integrity and cytokine expression in Caco-2/TC7 cells. The PKC and p38MAPK signaling pathways were involved in this AhR action.

Conclusions

The results of these series of human, mouse, and cell culture experiments demonstrate the protective effect of AhR activation in the intestine targeting particularly tight junctions and cytokine expression. We propose that AhR constitutes a valuable target to protect intestinal functions in metabolic diseases, which can be achieved in the future via food or drug ligands.

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Intestinal inflammation in obese subjects correlates with low AhR activity.

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AhR activation protects intestinal epithelium from damages.

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AhR activation prevents cytokine induction in response to damages.

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Protective role of AhR activation targets junctional complexes.

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Protein kinases-dependent signaling pathways are involved in AhR action.