Mechanical regulation of lipid and sugar absorption by Piezo1 in enterocytes.

Obesity is primarily caused by excessive intake as well as absorption of sugar and lipid. Postprandial surge in distention pressure and intestinal motility accelerates the absorption of nutrients. The response of intestinal epithelial cells to mechanical stimulation is not fully understood. Piezo1, a mechanosensitive ion channel, is widely expressed throughout the digestive tract. However, its function in intestinal nutrient absorption is not yet clear. In our study, excessive lipid deposition was observed in the duodenum of obese patients, while duodenal Piezo1-CaMKK2-AMPKα was decreased when compared to normal-weight individuals. Under high-fat diet condition, the Piezo1 iKO mice exhibited abnormally elevated sugar and lipid absorption as well as severe lipid deposition in the duodenum and liver. These phenotypes were mainly caused by the inhibition of duodenal CaMKK2-AMPKα and the upregulation of SGLT1 and DGAT2. In contrast, Yoda1, a Piezo1 agonist, was found to reduce intestinal lipid absorption in diet induced obese mice. Overexpression of Piezo1, stretch and Yoda1 inhibited lipid accumulation and the expression of DGAT2 and SGLT1, whereas knockdown of Piezo1 stimulated lipid accumulation and DGAT2 in Caco-2 cells. Our study reveals a previously unexplored mechanical regulation of nutrient absorption in intestinal epithelial cells, which may shed new light on the therapy of obesity.

Suppressive Effect of Coffee Leaves on Lipid Digestion and Absorption In Vitro.

BACKGROUND: Coffee leaves are a major source of bioactive components and are used as ethnomedicine. However, despite their traditional medicinal use, information about their effects on antihyperlipidemia remains limited. METHODS: The aims of this study were to evaluate the main components of leaf extracts from Arabica and Robusta coffees and to examine the potential of these coffee leaves in reducing lipid digestion and absorption in vitro. RESULTS: Coffee leaf extracts from Arabica coffee contain a high amount of caffeine, whereas extracts from Robusta coffee contain high amounts of chlorogenic acid (CGA) and caffeine. Additionally, leaf extracts from Arabica and Robusta coffee demonstrated the inhibition of pancreatic lipase, decreased micellar cholesterol solubility, and reduced bile acid binding. Furthermore, these extracts resulted in a reduction in cholesterol uptake in Caco-2 cells. Molecular docking experiments supported this discovery, showing CGA and caffeine binding to Niemann-Pick C1-like 1 (NPC1L1), a key protein in cholesterol absorption. The results indicated that CGA and caffeine can competitively bind to NPC1L1 at the cholesterol binding pocket, reducing its cholesterol binding rate. These findings suggest that coffee leaves might help suppress lipid absorption and digestion, highlighting their potential use in preventing and treating hyperlipidemia.

Platycodon D reduces obesity and non-alcoholic fatty liver disease induced by a high-fat diet through inhibiting intestinal fat absorption.

Background: Platycodin D (PD) has been reported to treat metabolic diseases, including non-alcoholic fatty liver disease. In addition, platycodin D has been reported to activate intestinal 5'AMP-activated protein kinase (AMPK) phosphorylation levels, thereby reducing lipid absorption. Therefore, the aim of this study is to explore whether PD activation of intestinal AMPK and reduced lipid absorption can improve non-alcoholic fatty liver disease. Methods: Clean-grade male C57/BL mice were fed a high-fat diet (HFD) (containing 60% calories) for 16 weeks, and oral PD (10 mg/kg/day) was administered at the same time. The liver and intestines were the collected, and the intestines were tested. The expressions of lipid absorption genes (CD36, NPC1L1, and ApoB), the serum total triglyceride (TG) and total cholesterol (TC) levels in the intestines and livers, the fecal free fatty acid (FFA) levels, and the expression of AMPK phosphorylated proteins in the intestines were examined using Western blot analyses. The lipid distribution in the livers, intestines, and fat was detected using Oil Red O and hematoxylin and eosin (H&E) staining. A colon cancer cell line (Caco2) was used to confirm the effect of PD on the cellular lipid uptake in vitro. In addition, serum inflammatory factors and liver enzymes were measured to clarify the impact of PD on the circulation of metabolic syndrome. Leptin-deficient mice (OB) were then used to further explore the improvement of PD on body weight and blood lipids. Results: PD had a very significant therapeutic or preventive effect on metabolic syndrome and fatty liver induced by a high-fat diet. PD improved body weight, insulin sensitivity, and glucose tolerance in mice fed a high-fat diet and also prevented non-alcoholic fatty liver disease, reduced blood lipid levels, and increased fecal lipid excretion. In addition, PD reduced lipid absorption by activating the intestinal AMPK protein, which may have involved the inhibition of the gene expression levels of intestinal lipid absorption genes (CD36, NPC1L1, and ApoB). The combined effect of these factors improved hepatic lipid accumulation and lipid accumulation in adipose tissue. It was further found that PD also improved the body weights and blood lipid levels of leptin-deficient mice (OB) mice. Conclusion: PD had a very strong therapeutic effect on mice under a high-fat diet. PD reduced high-fat diet-induced obesity and non-alcoholic fatty liver disease by inhibiting intestinal fat absorption.

Xanthine oxidase promotes hepatic lipid accumulation through high fat absorption by the small intestine.

Background & Aims: There are no studies investigating the direct effects of elevated xanthine oxidase (XO) on lipid metabolism disorders. Here, we aimed to clarify the role of XO in lipid metabolism in a prospective cohort study and elucidate the underlying mechanisms. Methods: The association between serum XO activity and metabolic associated steatotic liver disease (MASLD) was examined in Cox proportional hazard models in a population-based cohort of 3,358 participants (20-75 years) at baseline. In addition, mouse models were used to investigate the underlying mechanism for the association between overexpression of XO and the lipid metabolism disorders. Results: After an average 5.8 years of follow up, we found elevated serum XO activity was associated with an increased risk of developing MASLD (hazard ratio [HR]: 2.08; 95% CI: 1.44-3.01; p-trend <0.001). Moreover, serum XO activity was significantly associated with serum triglyceride levels (r = 0.68, p <0.001). We demonstrated that hepatic XO expression increased in liver samples from patients with MASLD. Using tissue-specific Xdh knockin mice, we observed rapid lipid metabolism disorders under a high-fat diet rather than a normal chow diet. We found that XO overexpression promotes the absorption of excess dietary fat in the small intestine. Inhibition of XO also significantly reduced the absorption of fat in mice fed a high-fat diet. Conclusions: Our study clarified the association between serum XO activity levels and the development of MASLD in a large population-based prospective cohort study. Furthermore, our mouse models demonstrated that XO overexpression promotes lipid accumulation through mechanisms involving excessive fat absorption by the small intestine. Impact and implications: Using a prospective population-based cohort and various animal models, we have identified novel mechanisms by which xanthine oxidase regulates lipid metabolism. Our findings indicate that xanthine oxidase overexpression promotes lipid accumulation by increasing the absorption of excess dietary fat and possibly facilitating lipid transport in vivo. These results could be important for the development of therapies to treat diseases associated with lipid metabolism disorders.

O-GlcNAc modification in endothelial cells modulates adiposity via fat absorption from the intestine in mice.

Introduction: Endothelial cells have a crucial function in transporting and exchanging various nutrients. O-GlcNAcylation, mediated by O-GlcNAc transferase (OGT), involves the addition of N-acetylglucosamine to proteins and serves as an intracellular nutrient sensing mechanism. However, the role of O-GlcNAcylation in endothelial cells remains poorly understood. Objective: This study investigated the role of O-GlcNAcylation in endothelial cells. Methods: Endothelial-cell-specific Ogt -knockout mice (Ogt-ECKO) were generated by crossing Ogt-floxed mice (Ogt-flox) with VE-Cadherin Cre ERT2 mice. Ogt-ECKO mice and Ogt-flox control mice were subjected to a normal or high-fat diet, and their body weight, glucose metabolism, and lipid metabolism were examined. Results: Ogt-ECKO mice exhibited reduced body weight compared with Ogt-flox control mice under a high-fat diet. Lipid absorption was significantly impaired in Ogt-ECKO mice. Changes in the intercellular junctions of small intestinal lacteal endothelial cells from a button-like to a zipper-like configuration were observed. Furthermore, Ogt-ECKO mice showed decreased expression of VEGFR3. The administration of a nitric oxide donor restored lipid absorption and reversed the morphological alterations in Ogt-ECKO mice. Conclusions: These findings demonstrate the critical role of O-GlcNAcylation in endothelial cells in lipid absorption in the intestine through the modulation of lacteal junction morphology. These results provide novel insight into the metabolic regulatory mechanisms under physiological conditions and have implications for the development of new therapeutic strategies for obesity.

Evaluation of the pharmacokinetics, chylomicron inhibition, and toxicity of colchicine in rats given low doses.

Colchicine (COL) is known for its ability to inhibit the formation of intestinal chylomicrons and has been utilized as a non-surgical tool to explore drug absorption via the intestinal lymphatics. However, there is limited understanding of its pharmacokinetics and its relationship to effect and toxicity with the doses used. This study aimed to provide comprehensive COL pharmacokinetic data and correlate it with the lymphatic-blocking and toxicological effects of low-doses. Male Sprague-Dawley rats with jugular-vein cannulation (JVC) received 0.1 to 0.5 mg/kg COL via oral, 0.25 mg/kg intraperitoneal, and 0.1 mg/kg intravenous routes, followed by blood and urine sampling for LC-MS/MS analysis. Effects on lipid absorption were assessed in another eight JVC rats receiving peanut oil with and without COL, followed by blood pharmacokinetic and plasma biochemistry analysis. The results revealed that COL exhibited moderate extraction ratio and high volume of distribution, with low oral bioavailability (<8%). About 20 % was recovered in the urine after parenteral dosing. Modest but significant reductions in cholesterol absorption was observed after oral doses of 0.5 mg/kg, accompanied by signs of inflammation and increased liver enzymes persisting for a week. The effect of COL on triglycerides formation was not significant. Despite its use as a non-surgical tool in rats to investigate drug absorption via the lymphatic pathway, COL demonstrated increased levels of liver function enzymes, emphasizing the need for caution and dose optimization in its utilization.

Obesity-enriched gut microbe degrades myo-inositol and promotes lipid absorption.

Numerous studies have reported critical roles for the gut microbiota in obesity. However, the specific microbes that causally contribute to obesity and the underlying mechanisms remain undetermined. Here, we conducted shotgun metagenomic sequencing in a Chinese cohort of 631 obese subjects and 374 normal-weight controls and identified a Megamonas-dominated, enterotype-like cluster enriched in obese subjects. Among this cohort, the presence of Megamonas and polygenic risk exhibited an additive impact on obesity. Megamonas rupellensis possessed genes for myo-inositol degradation, as demonstrated in vitro and in vivo, and the addition of myo-inositol effectively inhibited fatty acid absorption in intestinal organoids. Furthermore, mice colonized with M. rupellensis or E. coli heterologously expressing the myo-inositol-degrading iolG gene exhibited enhanced intestinal lipid absorption, thereby leading to obesity. Altogether, our findings uncover roles for M. rupellensis as a myo-inositol degrader that enhances lipid absorption and obesity, suggesting potential strategies for future obesity management.

Effects of Saponins on Lipid Metabolism: The Gut-Liver Axis Plays a Key Role.

Unhealthy lifestyles (high-fat diet, smoking, alcohol consumption, too little exercise, etc.) in the current society are prone to cause lipid metabolism disorders affecting the health of the organism and inducing the occurrence of diseases. Saponins, as biologically active substances present in plants, have lipid-lowering, inflammation-reducing, and anti-atherosclerotic effects. Saponins are thought to be involved in the regulation of lipid metabolism in the body; it suppresses the appetite and, thus, reduces energy intake by modulating pro-opiomelanocortin/Cocaine amphetamine regulated transcript (POMC/CART) neurons and neuropeptide Y/agouti-related peptide (NPY/AGRP) neurons in the hypothalamus, the appetite control center. Saponins directly activate the AMP-activated protein kinase (AMPK) signaling pathway and related transcriptional regulators such as peroxisome-proliferator-activated-receptors (PPAR), CCAAT/enhancer-binding proteins (C/EBP), and sterol-regulatory element binding proteins (SREBP) increase fatty acid oxidation and inhibit lipid synthesis. It also modulates gut-liver interactions to improve lipid metabolism by regulating gut microbes and their metabolites and derivatives-short-chain fatty acids (SCFAs), bile acids (BAs), trimethylamine (TMA), lipopolysaccharide (LPS), et al. This paper reviews the positive effects of different saponins on lipid metabolism disorders, suggesting that the gut-liver axis plays a crucial role in improving lipid metabolism processes and may be used as a therapeutic target to provide new strategies for treating lipid metabolism disorders.

A new mechanism of thyroid hormone receptor ß agonists ameliorating nonalcoholic steatohepatitis by inhibiting intestinal lipid absorption via remodeling bile acid profiles.

Excessive dietary calories lead to systemic metabolic disorders, disturb hepatic lipid metabolism, and aggravate nonalcoholic steatohepatitis (NASH). Bile acids (BAs) play key roles in regulating nutrition absorption and systemic energy homeostasis. Resmetirom is a selective thyroid hormone receptor ß (THRß) agonist and the first approved drug for NASH treatment. It is well known that the THRß activation could promote intrahepatic lipid catabolism and improve mitochondrial function, however, its effects on intestinal lipid absorption and BA compositions remain unknown. In the present study, the choline-deficient, L-amino acid defined, high-fat diet (CDAHFD) and high-fat diet plus CCl4 (HFD+CCl4)-induced NASH mice were used to evaluate the effects of resmetirom on lipid and BA composition. We showed that resmetirom administration (10 mg·kg-1·d-1, i.g.) significantly altered hepatic lipid composition, especially reduced the C18:2 fatty acyl chain-containing triglyceride (TG) and phosphatidylcholine (PC) in the two NASH mouse models, suggesting that THRß activation inhibited intestinal lipid absorption since C18:2 fatty acid could be obtained only from diet. Targeted analysis of BAs showed that resmetirom treatment markedly reduced the hepatic and intestinal 12-OH to non-12-OH BAs ratio by suppressing cytochrome P450 8B1 (CYP8B1) expression in both NASH mouse models. The direct inhibition by resmetirom on intestinal lipid absorption was further verified by the BODIPY gavage and the oral fat tolerance test. In addition, disturbance of the altered BA profiles by exogenous cholic acid (CA) supplementation abolished the inhibitory effects of resmetirom on intestinal lipid absorption in both normal and CDAHFD-fed mice, suggesting that resmetirom inhibited intestinal lipid absorption by reducing 12-OH BAs content. In conclusion, we discovered a novel mechanism of THRß agonists on NASH treatment by inhibiting intestinal lipid absorption through remodeling BAs composition, which highlights the multiple regulation of THRß activation on lipid metabolism and extends the current knowledge on the action mechanisms of THRß agonists in NASH treatment.

Traditional Chinese Medicine formula Dai-Zong-Fang alleviating hepatic steatosis in db/db mice via gut microbiota modulation.

Introduction: Hepatic steatosis is a hepatic pathological change closely associated with metabolic disorders, commonly observed in various metabolic diseases such as metabolic syndrome (MetS), with a high global prevalence. Dai-Zong-Fang (DZF), a traditional Chinese herbal formula, is widely used in clinical treatment for MetS, exhibiting multifaceted effects in reducing obesity and regulating blood glucose and lipids. This study aims to explore the mechanism by which DZF modulates the gut microbiota and reduces hepatic steatosis based on the gut-liver axis. Methods: This study utilized db/db mice as a disease model for drug intervention. Body weight and fasting blood glucose were monitored. Serum lipid and transaminase levels were measured. Insulin tolerance test was conducted to assess insulin sensitivity. Hematoxylin and eosin (HE) staining was employed to observe morphological changes in the liver and intestine. The degree of hepatic steatosis was evaluated through Oil Red O staining and hepatic lipid determination. Changes in gut microbiota were assessed using 16S rRNA gene sequencing. Serum lipopolysaccharide (LPS) levels were measured by ELISA. The expression levels of intestinal tight junction proteins, intestinal lipid absorption-related proteins, and key proteins in hepatic lipid metabolism were examined through Western blot and RT-qPCR. Results: After DZF intervention, there was a decrease in body weight, alleviation of glucose and lipid metabolism disorders, reduction in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, and mitigation of insulin resistance in mice. DZF significantly modulated the diversity of the gut microbiota, with a notable increase in the abundance of the Bacteroidetes phylum. PICRUSt indicated that DZF influenced various functions in gut microbiota, including carbohydrate and amino acid metabolism. Following DZF intervention, serum LPS levels decreased, intestinal pathological damage was reduced, and the expression of intestinal tight junction protein occludin was increased, while the expression of intestinal lipid absorption-related proteins cluster of differentiation 36 (CD36) and apolipoprotein B48 (ApoB48) were decreased. In the liver, DZF intervention resulted in a reduction in hepatic steatosis and lipid droplets, accompanied by a decrease fatty acid synthase (FASN) and stearoyl-CoA desaturase 1 (SCD1) and fatty acid transport protein 2 (FATP2). Conversely, there was an increase in the expression of the fatty acid oxidation-related enzyme carnitine palmitoyltransferase-1𝛂 (CPT-1𝛂). Conclusion: DZF can regulate the structure and function of the intestinal microbiota in db/db mice. This ameliorates intestinal barrier damage and the detrimental effects of endotoxemia on hepatic metabolism. DZF not only inhibits intestinal lipid absorption but also improves hepatic lipid metabolism from various aspects, including de novo lipogenesis, fatty acid uptake, and fatty acid oxidation. This suggests that DZF may act on the liver and intestine as target organs, exerting its effects by improving the intestinal microbiota and related barrier and lipid absorption functions, ultimately ameliorating hepatic steatosis and enhancing overall glucose and lipid metabolism.

The inhibition of inner mitochondrial fusion in hepatocytes reduces non-alcoholic fatty liver and improves metabolic profile during obesity by modulating bile acid conjugation.

AIMS: Mitochondria are plastic organelles that continuously undergo biogenesis, fusion, fission, and mitophagy to control cellular energy metabolism, calcium homeostasis, hormones, sterols, and bile acids (BAs) synthesis. Here, we evaluated how the impairment of mitochondrial fusion in hepatocytes affects diet-induced liver steatosis and obesity. METHODS AND RESULTS: Male mice selectively lacking the key protein involved in inner mitochondrial fusion, optic atrophy 1 (OPA1) (OPA1ΔHep) were fed a high fat diet (HFD) for 20 weeks. OPA1ΔHep mice were protected from the development of hepatic steatosis and obesity because of reduced lipid absorption; a profile which was accompanied by increased respiratory exchange ratio in vivo, suggesting a preference for carbohydrates in OPA1ΔHep compared to controls. At the molecular level, this phenotype emerged as a consequence of poor mitochondria-peroxisome- endoplasmic reticulum (ER) tethering in OPA1 deficient hepatocytes, which impaired BAs conjugation and release in the bile, thus impacting lipid absorption from the diet. Concordantly, the liver of subjects with non-alcoholic fatty liver disease (NAFLD) presented an increased expression of OPA1 and of the network of proteins involved in mitochondrial function when compared with controls. CONCLUSION: Patients with NAFLD present increased expression of proteins involved in mitochondrial fusion in the liver. The selective deficency of OPA1 in hepatocytes protects mice from HFD-induced metabolic dysfunction by reducing BAs secretion and dietary lipids absorption as a consequence of reduced liver mitochondria-peroxisome-ER tethering.

Intestinal SURF4 is essential for apolipoprotein transport and lipoprotein secretion.

OBJECTIVE: Lipoprotein assembly and secretion in the small intestine are critical for dietary fat absorption. Surfeit locus protein 4 (SURF4) serves as a cargo receptor, facilitating the cellular transport of multiple proteins and mediating hepatic lipid secretion in vivo. However, its involvement in intestinal lipid secretion is not fully understood. In this study, we investigated the role of SURF4 in intestinal lipid absorption. METHODS: We generated intestine-specific Surf4 knockout mice and characterized the phenotypes. Additionally, we investigated the underlying mechanisms of SURF4 in intestinal lipid secretion using proteomics and cellular models. RESULTS: We unveiled that SURF4 is indispensable for apolipoprotein transport and lipoprotein secretion. Intestine-specific Surf4 knockout mice exhibited ectopic lipid deposition in the small intestine and hypolipidemia. Deletion of SURF4 impeded the transport of apolipoprotein A1 (ApoA1), proline-rich acidic protein 1 (PRAP1), and apolipoprotein B48 (ApoB48) and hindered the assembly and secretion of chylomicrons and high-density lipoproteins. CONCLUSIONS: SURF4 emerges as a pivotal regulator of intestinal lipid absorption via mediating the secretion of ApoA1, PRAP1 and ApoB48.

Pharmacokinetics of cycloheximide in rats and evaluation of its effect as a blocker of intestinal lymph formation.

Cycloheximide (CHX) has been used to reduce the flow of intestinal lymph and as a non-surgical tool to study drug absorption via the intestinal lymphatics. Pharmacokinetic information on the agent, and its relationship to effect and toxicity, have not been examined. The goal of this study was to provide pharmacokinetic data and link it to lymph-blocking and toxicological effects. Jugular-vein cannulated (JVC) adult Sprague-Dawley male rats were administered 0.5 mg/kg CHX by oral, intraperitoneal (ip), and intravenous routes followed by blood draws, and CHX was assayed using LC-MS/MS. Another four JVC rats were given peanut oil (2 mL/kg) without and then with CHX to measure effects on lipid absorption as a surrogate indicator of lymph flow. One-week later plasma biochemistry measures were obtained. The results indicated that CHX had a high clearance and volume of distribution, and oral absolute bioavailability of 0.47 with 0.5 mg/kg. CHX was associated with dose- and route-dependent pharmacokinetics. The relative bioavailability after ip doses was over 3. CHX had low plasma protein binding and minor urinary excretion. Metabolism appeared to be occur by oxidation and glucuronidation. Reductions in plasma lipids (24-40 %) were seen after 2.5 mg/kg orally with signs of inflammation and increased liver enzymes persisting for a week after the dose. CHX was associated with a reduction in lipid absorption after oral doses of 2.5 mg/kg, which seems to justify its use as a non-surgical tool to evaluate the lymphatic pathway of absorption of drugs. However, it also possesses hepatotoxicity, which should be taken into consideration in its use.

Si-Ni-San reverses dietary fat absorption defects in a murine model of depression.

Depression is often associated with fatigue/energy loss. However, we lack a detailed understanding of the factors explaining this association. In this study, we uncovered that depressed mice have a defect in fat absorption, resulting in weight loss and reduced circulating lipid levels. Si-Ni-San (SNS), a basic formula of traditional Chinese medicine (TCM) for the treatment of depression, was found to not only alleviate depression-like behaviors, but also reverse the weight loss and dietary fat absorption of depressed mice. We found that SNS improved body weight and circulating lipid levels of depressed mice by up-regulating proteins [such as FFA uptake protein (CD36), TAG synthesis proteins (GPAT3, MOGAT2, DGAT1 and DGAT2) and chylomicron packaging proteins (MTP and APOB)] in the fat absorption pathway. Furthermore, cell-based results conducted with LPS-stimulated mouse MODE-K and human Caco-2 cells support that SNS, as well as Sinensetin (SIN) and Nobiletin (NOB), the two active components of the formula, have a role in regulating lipid absorption. Mechanistic studies revealed that SNS reverses body weight and fat absorption defects of depressed mice in part through the NR1D1/BMAL1/DGAT2 axis. These findings advance our understanding of the crosstalk between depression and energy loss, highlight the importance of gut function in disease management, and provide a basis for the application of SNS in the clinical treatment of depression and related disorders.

Agaricus bisporus Extract Exerts an Anti-Obesity Effect in High-Fat Diet-Induced Obese C57BL/6N Mice by Inhibiting Pancreatic Lipase-Mediated Fat Absorption.

Agaricus bisporus is well known as a source of polysaccharides that could improve human health. The objective of this study was to explore the anti-obesity effect of A. bisporus extract (ABE), abundant in polysaccharides, and its underlying mechanism. Pancreatic lipase inhibitory activity in vitro was determined after treatment with ABE and chitosan. Treatment with ABE and chitosan significantly decreased pancreatic lipase activity. Five-week-old male SD rats were randomly divided into three groups for acute feeding with vehicle, ABE at 80 mg/kg body weight (BW)/day, and ABE at 160 mg/kg BW/day. ABE dose-dependently increased plasma lipid clearance in an oral lipid tolerance test. Five-week-old male C57BL/6N mice were fed a control diet (CD), a high-fat diet (HFD), an HFD with ABE at 80 mg/kg BW/day, ABE at 160 mg/kg BW/day, or chitosan at 160 mg/kg BW/day for eight weeks. HFD-fed mice showed significant increases in body weight, fat mass, white adipose tissue, average lipid droplet size, and serum levels of glucose, triglyceride, ALT, and AST compared to those in the CD group. However, ABE or chitosan administration ameliorated these increases. ABE or chitosan significantly reduced dietary efficiency and increased fecal excretion levels of lipids, triglycerides, and total cholesterol. These in vitro and in vivo findings suggest that ABE might act as an anti-obesity agent by inhibiting pancreatic lipase-mediated lipid absorption, at least in part.

LRP1 as a promising therapeutic target for gastrointestinal tumors: Inhibiting proliferation, invasion and migration of cancer cells.

Gastrointestinal (GI) cancers are the most common types of tumors worldwide. The lack of cancer biomarkers and targeted drug resistance are barriers to achieving effective cancer therapy. Low-density lipoprotein receptor-related protein 1 (LRP1) is a transmembrane protein that has multiple functions due to its ability to recognize different ligands; however, the role of LRP1 in GI cancer cells remains unclear. The present study aimed to investigate the role of LRP1 in GI tumors. The Cancer Genome Atlas database was used to analyze the potential correlation between expression of LRP1 and prognosis in patients with GI cancer. Bioinformatics analysis was utilized and the expression of LRP1 was simultaneously validated in GI cancer at the cellular level through western blot experiments. LRP1 was expressed at high levels in HGC-27, HepG2 and BxPC-3 cells. LRP1 expression in GI cancer cells was knocked down using lentivirus-mediated shRNA and the effects on biological functions were observed. LRP1 knockdown suppressed the proliferation, invasion and migration of GI cancer cells. LRP1 knockdown inhibited CD36 gene expression in HepG2 and BxPC-3 cells. LRP1 knockdown inhibited the proliferation, invasion and migration of GI cancer cells, suggesting that LRP1 may be a novel target for treatment of GI tumors.

Isoxanthohumol improves obesity and glucose metabolism via inhibiting intestinal lipid absorption with a bloom of Akkermansia muciniphila in mice.

OBJECTIVE: Polyphenols have health-promoting effects, such as improving insulin resistance. Isoxanthohumol (IX), a prenylated flavonoid found in beer hops, has been suggested to reduce obesity and insulin resistance; however, the mechanism remains unknown. METHODS: High-fat diet-fed mice were administered IX. We analyzed glucose metabolism, gene expression profiles and histology of liver, epididymal adipose tissue and colon. Lipase activity, fecal lipid profiles and plasma metabolomic analysis were assessed. Fecal 16s rRNA sequencing was obtained and selected bacterial species were used for in vitro studies. Fecal microbiota transplantation and monocolonization were conducted to antibiotic-treated or germ-free (GF) mice. RESULTS: The administration of IX lowered weight gain, decreased steatohepatitis and improved glucose metabolism. Mechanistically, IX inhibited pancreatic lipase activity and lipid absorption by decreasing the expression of the fatty acid transporter CD36 in the small intestine, which was confirmed by increased lipid excretion in feces. IX administration increased markers of intestinal barrier function, including thickening the mucin layer and increasing caludin-1, a tight-junction related protein in the colon. In contrast, the effects of IX were nullified by antibiotics. As revealed using 16S rRNA sequencing, the microbial community structure changed with a significant increase in the abundance of Akkermansia muciniphila in the IX-treated group. An anaerobic chamber study showed that IX selectively promoted the growth of A. muciniphila while exhibiting antimicrobial activity against some Bacteroides and Clostridium species. To further explore the direct effect of A. muciniphila on lipid and glucose metabolism, we monocolonized either A. muciniphila or Bacteroides thetaiotaomicron to GF mice. A. muciniphila monocolonization decreased CD36 expression in the jejunum and improved glucose metabolism, with decreased levels of multiple classes of fatty acids determined using plasma metabolomic analysis. CONCLUSIONS: Our study demonstrated that IX prevents obesity and enhances glucose metabolism by inhibiting dietary fat absorption. This mechanism is linked to suppressing pancreatic lipase activity and shifts in microbial composition, notably an increase in A. muciniphila. These highlight new treatment strategies for preventing metabolic syndrome by boosting the gut microbiota with food components.

Solanum aethiopicum L. from the Basilicata Region Prevents Lipid Absorption, Fat Accumulation, Oxidative Stress, and Inflammation in OA-Treated HepG2 and Caco-2 Cell Lines.

Obesity is widely associated with intestine barrier impairment, nonalcoholic fatty liver disease (NAFLD) outbreaks, oxidative stress, and inflammation. In a previous investigation, the Solanum aethiopicum L. growing in Basilicata Region has demonstrated to have antioxidant activity; hence this investigation was aimed to evaluate for the first time the antilipidemic and anti-inflammatory activity of the Lucanian S. aethiopicum L. peel extract in vitro on OA-treated HepG2 and Caco-2 cell lines. It was shown that the extract could reduce lipogenesis by down-regulating SREBP-1c and HMGCR expression and fatty acid ß-oxidation by up-regulating PPARα, CPT1A, and UCP2 expression. In addition, the S. aethiopicum L. peel extract might also improve oxidative stress by reducing endoplasmic reticulum stress and regulating the Nrf2 and Nf-κB molecular pathways. Altogether, these results demonstrated for the first time the possible application of the Lucanian S. aethiopicum peel extract for preventing obesity and managing NAFLD.

Reduced intestinal lipid absorption improves glucose metabolism in aged G2-Terc knockout mice.

BACKGROUND: Biological aging is an important factor leading to the development of pathologies associated with metabolic dysregulation, including type 2 diabetes, cancer, cardiovascular and neurodegenerative diseases. Telomere length, a central feature of aging, has additionally been identified as inversely associated with glucose tolerance and the development of type 2 diabetes. However, the effects of shortened telomeres on body weight and metabolism remain incompletely understood. Here, we studied the metabolic consequences of moderate telomere shortening using second generation loss of telomerase activity in mice. RESULTS: Aged male and female G2 Terc-/- mice and controls were characterized with respect to body weight and composition, glucose homeostasis, insulin sensitivity and metabolic activity. This was complemented with molecular and histological analysis of adipose tissue, liver and the intestine as well as microbiota analysis. We show that moderate telomere shortening leads to improved insulin sensitivity and glucose tolerance in aged male and female G2 Terc-/- mice. This is accompanied by reduced fat and lean mass in both sexes. Mechanistically, the metabolic improvement results from reduced dietary lipid uptake in the intestine, characterized by reduced gene expression of fatty acid transporters in enterocytes of the small intestine. Furthermore, G2-Terc-/- mice showed significant alterations in the composition of gut microbiota, potentially contributing to the improved glucose metabolism. CONCLUSIONS: Our study shows that moderate telomere shortening reduces intestinal lipid absorption, resulting in reduced adiposity and improved glucose metabolism in aged mice. These findings will guide future murine and human aging studies and provide important insights into the age associated development of type 2 diabetes and metabolic syndrome.

Sulfosuccinimidyl oleate ameliorates the high-fat diet-induced obesity syndrome by reducing intestinal and hepatic absorption.

Background: A high-fat Western diet is a risk factor for obesity and steatosis. Reducing intestinal absorption of a high-fat diet (HFD) is a feasible strategy to control obesity. Sulfosuccinimidyl oleate (SSO) inhibits intestinal fatty acid transport. Therefore, the aim of this study was to investigate the effects of SSO on HFD-induced glucose and lipid metabolism in mice and its possible underlying mechanisms. Methods: Male C57/BL were fed a HFD (60% calories) for 12 weeks and were administered an oral dose of SSO (50 mg/kg/day). The expression of lipid absorption genes (CD36, MTTP, and DGAT1) and the serum levels of triglycerides (TGs), total cholesterol (TC), and free fatty acids (FFAs) were detected. Lipid distribution in the liver was detected by oil red and hematoxylin and eosin staining. In addition, serum levels of inflammatory factors, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were measured to detect side effects. Results: SSO was effective in the treatment of obesity and metabolic syndrome induced by HFD in mice. It attenuated the assembly of intestinal epithelial chylomicrons by inhibiting intestinal epithelial transport and absorption of fatty acids, thereby reducing the gene expression levels of MTTP and DGAT1, resulting in decreased plasma TG and FFA levels. At the same time, it inhibited the transport of fatty acids in the liver and improved the steatosis induced by a HFD. The results of oil red staining showed that SSO treatment can reduce lipid accumulation in the liver by 70%, with no drug-induced liver injury detected on the basis of interleukin-6, C-reactive protein, ALT, and AST levels. In addition, SSO treatment significantly improved insulin resistance, decreased fasting blood glucose levels, and improved glucose tolerance in HFD-fed mice. Conclusion: SSO is effective in the treatment of obesity and metabolic syndrome induced by a HFD in mice. SSO reduces intestinal fatty acid absorption by reducing the inhibition of intestinal CD36 expression, followed by decreased TG and FFA levels, which attenuates HFD-induced fatty liver.