Green tea extract treatment reduces NFκB activation in mice with diet-induced nonalcoholic steatohepatitis by lowering TNFR1 and TLR4 expression and ligand availability

Spinal cord injury-induced metabolic impairment and steatohepatitis develops in non-obese rats and is exacerbated by premorbid obesity

Impaired sensorimotor functions are prominent complications of spinal cord injury (SCI). A clinically important but less obvious consequence is development of metabolic syndrome (MetS), including increased adiposity, hyperglycemia/insulin resistance, and hyperlipidemia. MetS predisposes SCI individuals to earlier and more severe diabetes and cardiovascular disease compared to the general population, which trigger life-threatening complications (e.g., stroke, myocardial infarcts). Although each comorbidity is known to be a risk factor for diabetes and other health problems in obese individuals, their relative contribution or perceived importance in propagating systemic pathology after SCI has received less attention. This could be explained by an incomplete understanding of MetS promoted by SCI compared with that from the canonical trigger diet-induced obesity (DIO). Thus, here we compared metabolic-related outcomes after SCI in lean rats to those of uninjured rats with DIO. Surprisingly, SCI-induced MetS features were equal to or greater than those in obese uninjured rats, including insulin resistance, endotoxemia, hyperlipidemia, liver inflammation and steatosis. Considering the endemic nature of obesity, we also evaluated the effect of premorbid obesity in rats receiving SCI; the combination of DIO + SCI exacerbated MetS and liver pathology compared to either alone, suggesting that obese individuals that sustain a SCI are especially vulnerable to metabolic dysfunction. Notably, premorbid obesity also exacerbated intraspinal lesion pathology and worsened locomotor recovery after SCI. Overall, these results highlight that normal metabolic function requires intact spinal circuitry and that SCI is not just a sensory-motor disorder, but also has significant metabolic consequences.

A green tea extract confection decreases circulating endotoxin and fasting glucose by improving gut barrier function but without affecting systemic inflammation: A double-blind, placebo-controlled randomized trial in healthy adults and adults with metabolic syndrome

Anti-inflammatory activities of catechin-rich green tea extract (GTE) in obese rodents protect against metabolic endotoxemia by decreasing intestinal permeability and absorption of gut-derived endotoxin. However, translation to human health has not been established. We hypothesized that GTE would reduce endotoxemia by decreasing gut permeability and intestinal and systemic inflammation in persons with metabolic syndrome (MetS) compared with healthy persons. A randomized, double-blind, placebo-controlled, crossover trial in healthy adults (n = 19, 34 ± 2 years) and adults with MetS (n = 21, 40 ± 3 years) examined 4-week administration of a decaffeinated GTE confection (890 mg/d total catechins) on serum endotoxin, intestinal permeability, gut and systemic inflammation, and cardiometabolic parameters. Compared with the placebo, the GTE confection decreased serum endotoxin (P = .023) in both healthy persons and those with MetS, while increasing concentrations of circulating catechins (P < .0001) and γ-valerolactones (P = .0001). Fecal calprotectin (P = .029) and myeloperoxidase (P = .048) concentrations were decreased by GTE regardless of health status. Following the ingestion of gut permeability probes, urinary lactose/mannitol (P = .043) but not sucralose/erythritol (P > .05) was decreased by GTE regardless of health status. No between-treatment differences (P > .05) were observed for plasma aminotransferases, blood pressure, plasma lipids, or body mass nor were plasma tumor necrosis factor-α, interleukin-6, or the ratio of lipopolysaccharide-binding protein/soluble cluster of differentiation-14 affected. However, fasting glucose in both study groups was decreased (P = .029) by the GTE confection compared with within-treatment arm baseline concentrations. These findings demonstrate that catechin-rich GTE is effective to decrease circulating endotoxin and improve glycemic control in healthy adults and those with MetS, likely by reducing gut inflammation and small intestinal permeability but without affecting systemic inflammation.

Tea polyphenols alleviate TBBPA-induced inflammation, ferroptosis and apoptosis via TLR4/NF-κB pathway in carp gills

The extensive application of Tetrabromobisphenol A (TBBPA) leads to the pollution of part of the water environment and brings great safety risks to aquatic animals. As a natural extract, tea polyphenols (TPs) have antioxidant and anti-inflammatory effects. Gills are one of the immune organs of fish and constitute the first line of defense of the immune system. However, it was unclear whether TPs could mitigate TBBPA-induced gills injury. Therefore, an animal model was established to investigate the effect of TPs on TBBPA-induced gills. The results indicated that TBBPA changed the coefficient and tissue morphology of carp gills. In addition, TBBPA induced oxidative stress and inflammation, leading to ferroptosis and apoptosis in carp gills. Dietary addition of TPs significantly improved the antioxidant capacity of carp, effectively inhibited the overexpression of TLR4/NF-κB and its mediated inflammatory response. Moreover, TPs restored iron metabolism, reduced the expression of pro-apoptotic factors thereby alleviating ferroptosis and apoptosis in carp gills. This study enriched the protective effect of TPs and provided a new way to improve the innate immunity of carp.

Long-term drinking of green tea combined with exercise improves hepatic steatosis and obesity in male mice induced by high-fat diet

Dietary habits and exercise play an important role in the well-being of human health. Currently, how long of drinking tea combined with exercise could efficiently ameliorate hepatic steatosis and obesity still needs to be investigated. Here, short-term and long-term green tea drinking combined with exercise were studied to improve hepatic steatosis and obesity in high-fat diet-induced (HF) mice. Our results showed that Yunkang 10 green tea (GT) combined with exercise (Ex) exhibited synergistic prevention effects on ameliorating hepatic steatosis and obesity. Especially, 22-week intervention with GT or Ex improved all symptoms of obesity, which indicated that long-term intervention exhibited profound preventive effects than the short term. Moreover, the combined intervention of 22 weeks inhibited the activation of NF-κB pathway and the expression of proinflammatory cytokines, which suggests that tea combined exercise may improve liver steatosis mainly by inhibiting inflammation. The key molecules for regulating lipid and glucose metabolism SCD1 were obviously downregulated, and GLU2 and PPARγ were significantly upregulated by GT and exercise in the liver of high-fat diet-induced mice. This study demonstrated that long-term intervention with GT and exercise effectively relieved hepatic steatosis and obesity complications by ameliorating hepatic inflammation, reducing lipid synthesis, and accelerating glucose transport.

Catechin Bioavailability Following Consumption of a Green Tea Extract Confection Is Reduced in Obese Persons without Affecting Gut Microbial-Derived Valerolactones

Obesity-related cardiometabolic disorders are driven by inflammation, oxidative stress, and gut dysbiosis. Green tea catechins protect against cardiometabolic disorders by anti-inflammatory, antioxidant, and prebiotic activities. However, whether obesity alters catechin bioavailability remains unknown. We hypothesized that obesity would decrease catechin bioavailability due to altered gut microbiota composition. Obese and healthy persons completed a pharmacokinetics trial in which a confection formulated with green tea extract (GTE; 58% epigallocatechin gallate, 17% epigallocatechin, 8% epicatechin, 6% epicatechin gallate) was ingested before collecting plasma and urine at timed intervals for up to 24 h. Stool samples were collected prior to confection ingestion. Catechins and γ-valerolactones were assessed by LC-MS. Obesity reduced plasma area under the curve (AUC_0-12h) by 24-27% and maximum plasma concentrations by 18-36% for all catechins. Plasma AUC_0-12h for 5'-(3',4'-dihydroxyphenyl)-γ-valerolactone and 5'-(3',4',5'-trihydroxyphenyl)-γ-valerolactone, as well as total urinary elimination of all catechins and valerolactones, were unaffected. ⍺-Diversity in obese persons was lower, while Slackia was the only catechin-metabolizing bacteria that was altered by obesity. Ascorbic acid and diversity metrics were correlated with catechin/valerolactone bioavailability. These findings indicate that obesity reduces catechin bioavailability without affecting valerolactone generation, urinary catechin elimination, or substantially altered gut microbiota populations, suggesting a gut-level mechanism that limits catechin absorption.

EGCG and catechin relative to green tea extract differentially modulate the gut microbial metabolome and liver metabolome to prevent obesity in mice fed a high-fat diet

Green tea extract (GTE) alleviates obesity, in part, by modulating gut microbial composition and metabolism. However, direct evidence regarding the catechin-specific bioactivities that are responsible for these benefits remain unclear. The present study therefore investigated dietary supplementation of GTE, epigallocatechin gallate (EGCG), or (+)-catechin (CAT) in male C57BL6/J mice that were fed a high-fat (HF) diet to establish the independent contributions of EGCG and CAT relative to GTE to restore microbial and host metabolism. We hypothesized that EGCG would regulate the gut microbial metabolome and host liver metabolome more similar to GTE than CAT to explain their previously observed differential effects on cardiometabolic health. To test this, we assessed metabolic and phenolic shifts in liver and fecal samples during dietary HF-induced obesity. Ten fecal metabolites and ten liver metabolites (VIP > 2) primarily contributed to the differences in the metabolome among different interventions. In fecal samples, nine metabolic pathways (e.g., tricarboxcylic acid cycle and tyrosine metabolism) were differentially altered between the GTE and CAT interventions, whereas three pathways differed between GTE and EGCG interventions, suggesting differential benefits of GTE and its distinctive bioactive components on gut microbial metabolism. Likewise, hepatic glycolysis / gluconeogenesis metabolic pathways were significantly altered between GTE and EGCG interventions, while only hepatic tyrosine metabolism was altered between CAT and GTE interventions. Thus, our findings support that purified catechins relative to GTE uniquely contribute to regulating host and microbial metabolic pathways such as central energy metabolism to protect against metabolic dysfunction leading to obesity.

Bioactive compounds modulating Toll-like 4 receptor (TLR4)-mediated inflammation: pathways involved and future perspectives

Chronic inflammation is associated with the development and progression of several noncommunicable diseases, such as diabetes, cardiovascular disease, chronic kidney disease, cancer, and nonalcoholic fatty liver disease. Evidence suggests that pattern recognition receptors that identify pathogen-associated molecular patterns and danger-associated molecular patterns are crucial in chronic inflammation. Among the pattern recognition receptors, Toll-like receptor 4 (TLR4) stimulates several inflammatory pathway agonists, such as nuclear factor-κB, interferon regulator factor 3, and nod-like receptor pyrin domain containing 3 pathways, which consequently trigger the expression of pro-inflammatory biomarkers, increasing the risk of noncommunicable disease development and progression. Studies have focused on the antagonistic potential of bioactive compounds, following the concept of food as a medicine, in which nutritional strategies may mitigate inflammation via TLR4 modulation. Thus, this review discusses preclinical evidence concerning bioactive compounds from fruit, vegetable, spice, and herb extracts (curcumin, resveratrol, catechin, cinnamaldehyde, emodin, ginsenosides, quercetin, allicin, and caffeine) that may regulate the TLR4 pathway and reduce the inflammatory response. Bioactive compounds can inhibit TLR4-mediated inflammation through gut microbiota modulation, improvement of intestinal permeability, inhibition of lipopolysaccharide-TLR4 binding, and decreasing TLR4 expression by modulation of microRNAs and antioxidant pathways. The responses directly mitigated inflammation, especially nuclear factor-κB activation and inflammatory cytokines release. These findings should be considered for further clinical studies on inflammation-mediated diseases.

Chaihu Shugan powder alleviates liver inflammation and hepatic steatosis in NAFLD mice: A network pharmacology study and in vivo experimental validation

Background: Nonalcoholic fatty liver disease (NAFLD) is the most common metabolic disease and is intertwined with cardiovascular disorders and diabetes. Chaihu Shugan powder (CSP) is a traditional Chinese medicine with a significant therapeutic effect on metabolic diseases, such as NAFLD. However, its pharmacological mechanisms remain to be elucidated.

Methods: The main compounds of CSP were measured using LC-MS/MS. A network pharmacology study was conducted on CSP. Its potential active ingredients were selected according to oral bioavailability, drug similarity indices, and phytochemical analysis. After obtaining the intersected genes between drug targets and disease-related targets, the component-disease-target network and protein-protein interaction analysis were visualized in Cytoscape. GO and KEGG enrichment analyses were performed using the Metascape database. Six-week-old male C57BL/6 mice fed a high-fat high-fructose diet for 16 weeks plus chronic immobilization stress for 2 weeks, an in vivo model, were administered CSP or saline intragastrically. Liver histology, triglyceride and cholesterol levels, ELISA, and RT-PCR were used to assess hepatic inflammation and steatosis. Immunohistochemistry and western blotting were performed to assess protein levels.

Results: A total of 130 potential target genes in CSP that act on NAFLD were identified through network pharmacology assays, including tumor necrosis factor (TNF), interleukin-6 (IL6), interleukin-1β (IL-1β), and peroxisome proliferator-activated receptor γ (PPARG). KEGG enrichment analysis showed that the main pathways were involved in inflammatory pathways, such as the TNF and NF-κB signaling pathways, and metabolism-related pathways, such as the MAPK, HIF-1, FoxO, and AMPK signaling pathways. The results in vivo showed that CSP ameliorated liver inflammation and inhibited hepatic fatty acid synthesis in the hepatocyte steatosis model. More specifically, CSP therapy significantly inhibited the expression of tumor necrosis factor α (TNFα), accompanied by a decrease in TNF receptor 1 (TNFR1) and the ligand availability of TNFR1.

Conclusion: Through the combination of network pharmacology and in vivo validation, this study elucidated the therapeutic effect of CSP on NAFLD, decreasing liver inflammation and inhibiting hepatic fatty acid synthesis. More specifically, the anti-inflammatory action of CSP was at least partially mediated by inhibiting the TNFα/TNFR1 signaling pathway.

Daily Inclusion of Resistant Starch-Containing Potatoes in a Dietary Guidelines for Americans Dietary Pattern Does Not Adversely Affect Cardiometabolic Risk or Intestinal Permeability in Adults with Metabolic Syndrome: A Randomized Controlled Trial

Poor diet quality influences cardiometabolic risk. Although potatoes are suggested to adversely affect cardiometabolic health, controlled trials that can establish causality are limited. Consistent with potatoes being rich in micronutrients and resistant starch, we hypothesized that their inclusion in a Dietary Guidelines for Americans (DGA)-based dietary pattern would improve cardiometabolic and gut health in metabolic syndrome (MetS) persons. In a randomized cross-over trial, MetS persons (n = 27; 32.5 ± 1.3 year) consumed a DGA-based diet for 2 weeks containing potatoes (DGA + POTATO; 17.5 g/day resistant starch) or bagels (DGA + BAGEL; 0 g/day resistant starch) prior to completing oral glucose and gut permeability tests. Blood pressure, fasting glucose and insulin, and insulin resistance decreased (p < 0.05) from baseline regardless of treatment without any change in body mass. Oral glucose-induced changes in brachial artery flow-mediated dilation, nitric oxide homeostasis, and lipid peroxidation did not differ between treatment arms. Serum endotoxin AUC0−120 min and urinary lactulose/mannitol, but not urinary sucralose/erythritol, were lower in DGA + POTATO. Fecal microbiome showed limited between-treatment differences, but the proportion of acetate was higher in DGA + POTATO. Thus, short-term consumption of a DGA-based diet decreases cardiometabolic risk, and the incorporation of resistant starch-containing potatoes into a healthy diet reduces small intestinal permeability and postprandial endotoxemia.

Potential therapeutic effects of green tea on obese lipid profile - a systematic review

Background: Green tea, obtained from the plant Camellis sinensis, is one of the oldest drinks in the world and contains numerous bioactive compounds. Studies have demonstrated the efficacy of green tea in preventing obesity and cardiovascular diseases that may be related to the reduction of lipid levels. Aim: This study aimed to evidence, through a systematic review, the therapeutic potential of green tea on the lipid profile in preclinical studies in obese animals and clinical studies in obese individuals. Methods: This systematic review follows the recommendations of the preferred report items for systematic reviews and meta-analyses. The electronic databases, PubMed (Medline), Science Direct, Scopus, and Web of Science were consulted. Articles from January 2009 to December 2019 were selected. Results: This search resulted in twenty-nine articles were included cirtically reviewed. In experimental studies, green tea administration has been shown to reduce total cholesterol, triglycerides and low-density lipoprotein cholesterol in animals exposed to obesity-inducing diet. In humans' studies green tea was not shown to be effective for obese lipid control. Because supplementation with green tea extract reduced total cholesterol, triglycerides, low-density lipoprotein for three months at a specific dose. Conclusion: Therefore, green tea appears to act as a protective agent for dyslipidemia in obesity-induced animals. In human studies, green tea has not been shown to be effective in controlling obese lipids.

Green tea aqueous extract (GTAE) prevents high-fat diet-induced obesity by activating fat browning

Adipose browning leads to increased energy expenditure and reduced adiposity and has, therefore, become an attractive therapeutic strategy for obesity. In this study, we elucidated the effect of green tea aqueous extract (GTAE) on the browning of inguinal white adipose tissue (Ing-WAT) and brown adipose tissue (BAT) in high-fat diet (HFD)-fed mice. The main phytochemical components identified in GTAE through high-performance liquid chromatography (HPLC) included (-)-gallocatechin, (-)-epigallocatechin, (-)-catechin, (-)-epigallocatechin-3-gallate, caffeine, (-)-epicatechin, (-)-gallocatechin gallate, and (-)-epicatechin-3-gallate. Daily supplementation with 1% GTAE for 12 weeks markedly reduced bodyweight gain, systemic inflammation, oxidative stress, and improved insulin resistance. Additionally, histological analysis revealed that dietary supplementation with 1% GTAE reversed HFD-induced adipocyte size and hepatic steatosis. These effects were associated with activation of browning in the Ing-WAT and BAT, which mediate systemic metabolic dysfunction in HFD-fed mice. Taken together, our data support the use of GTAE, a natural product, for the attenuation of obesity through the activation of fat browning.

Antiinflammatory phytochemicals against virus-induced hyperinflammatory responses: Scope, rationale, application, and limitations

Uncontrolled inflammatory responses or cytokine storm associated with viral infections results in deleterious consequences such as vascular leakage, severe hemorrhage, shock, immune paralysis, multi-organ failure, and even death. With the emerging new viral infections and lack of effective prophylactic vaccines, evidence-based complementary strategies that limit viral infection-mediated hyperinflammatory responses could be a promising approach to limit host tissue injury. The present review emphasizes the potentials of antiinflammatory phytochemicals in limiting hyperinflammatory injury caused by viral infections. The predominant phytochemicals along with their mechanism in limiting hyperimmune and pro-inflammatory responses under viral infection have been reviewed comprehensively. How certain phytochemicals can be effective in limiting hyper-inflammatory response indirectly by favorably modulating gut microbiota and maintaining a functional intestinal barrier has also been presented. Finally, we have discussed improved systemic bioavailability of phytochemicals, efficient delivery strategies, and safety measures for effective antiinflammatory phytotherapies, in addition to emphasizing the requirement of tightly controlled clinical studies to establish the antiinflammatory efficacy of the phytochemicals. Collectively, the review provides a scooping overview on the potentials of bioactive phytochemicals to mitigate pro-inflammatory injury associated with viral infections.

Application of metabolomics for revealing the interventional effects of functional foods on metabolic diseases

Metabolomics is an important branch of systems biology, which can detect changes in the body's metabolism before and after the intervention of functional foods, identify effective metabolites, and predict the interventional effects and the mechanism. This review summarizes the latest research outcomes regarding interventional effects of functional foods on metabolic diseases via metabolomics analysis. Since metabolomics approaches are powerful strategies for revealing the changes in bioactive compounds of functional foods during processing and storage, we also discussed the effects of these parameters on functional food metabolites using metabolomics approaches. To date, a number of endogenous metabolites related to the metabolic diseases after functional foods intervention have been discovered. Unfortunately, the mechanisms of metabolic disease-related molecules are still unclear and require further studies. The combination of metabolomics with other omics technologies could further promote its ability to fully understand the precise biological processes of functional food intervention on metabolic diseases.

Green Tea and Epigallocatechin Gallate (EGCG) for the Management of Nonalcoholic Fatty Liver Diseases (NAFLD): Insights into the Role of Oxidative Stress and Antioxidant Mechanism

Nonalcoholic fatty liver diseases (NAFLD) represent a set of liver disorders progressing from steatosis to steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma, which induce huge burden to human health. Many pathophysiological factors are considered to influence NAFLD in a parallel pattern, involving insulin resistance, oxidative stress, lipotoxicity, mitochondrial dysfunction, endoplasmic reticulum stress, inflammatory cascades, fibrogenic reaction, etc. However, the underlying mechanisms, including those that induce NAFLD development, have not been fully understood. Specifically, oxidative stress, mainly mediated by excessive accumulation of reactive oxygen species, has participated in the multiple NAFLD-related signaling by serving as an accelerator. Ameliorating oxidative stress and maintaining redox homeostasis may be a promising approach for the management of NAFLD. Green tea is one of the most important dietary resources of natural antioxidants, above which epigallocatechin gallate (EGCG) notably contributes to its antioxidative action. Accumulative evidence from randomized clinical trials, systematic reviews, and meta-analysis has revealed the beneficial functions of green tea and EGCG in preventing and managing NAFLD, with acceptable safety in the patients. Abundant animal and cellular studies have demonstrated that green tea and EGCG may protect against NAFLD initiation and development by alleviating oxidative stress and the related metabolism dysfunction, inflammation, fibrosis, and tumorigenesis. The targeted signaling pathways may include, but are not limited to, NRF2, AMPK, SIRT1, NF-κB, TLR4/MYD88, TGF-β/SMAD, and PI3K/Akt/FoxO1, etc. In this review, we thoroughly discuss the oxidative stress-related mechanisms involved in NAFLD development, as well as summarize the protective effects and underlying mechanisms of green tea and EGCG against NAFLD.

Anthocyanins from the fruits of Lycium ruthenicum Murray improve high-fat diet-induced insulin resistance by ameliorating inflammation and oxidative stress in mice

A high-fat diet (HFD) promotes tissue inflammation, oxidative stress and insulin resistance (IR), thereby contributing to the development of obesity and diabetes. Anthocyanins from Lycium ruthenicum (AC) have demonstrated anti-obesity effects and modulated IR. To investigate the mechanism by which AC attenuates the adverse effects of consuming a HFD, C57BL/6J mice were fed a HFD supplemented with AC or a control diet without AC for 12 weeks. AC supplementation decreased the amount of weight gain, hepatic lipid, and sequentially improved dyslipidemia, inflammation, oxidative stress, and IR in HFD-fed mice. Molecular data revealed that AC inhibited hepatic inflammation by reducing TLR4/NF-κB/JNK in the liver tissues and ameliorated oxidative stress by activating the Nrf2/HO-1/NQO1 pathway. Thus, AC might activate IRS-1/AKT and prevent HFD-induced gluconeogenesis and IR by ameliorating inflammation and oxidative stress. Modulation of inflammation and oxidative stress with AC may represent a promising target for the treatment of IR and provide insight into the mechanism by which AC protects against obesity.

Beverages and Non-alcoholic fatty liver disease (NAFLD): Think before you drink

BACKGROUND & AIMS

Beverages and Non-alcoholic fatty liver disease (NAFLD) both the terms are associated with westernized diet and sedentary lifestyle. Throughout recent decades, dietary changes have boosted demand of beverages to meet the liquid consumption needs, among which rising consumption of several calorie-rich beverages have increased the risk of fatty liver disease. Meanwhile, certain beverages have capacity to deliver many unanticipated health benefits thereby reducing the burden of NAFLD and metabolic diseases. The present review therefore addresses the increasing interconnections between beverages intake among population, dietary patterns and the overall effect of these beverage on the development and prevention of NAFLD. Methods In the present review, some frequently consumed beverage groups have been analyzed in light of their role in the advancement and prevention of NAFLD, including sugar sweetened, hot and alcoholic beverages. The nutritional composition of different beverages makes the progression of NAFLD distinctive.

RESULTS

The ingestion of sugar-rich beverages has demonstrated the metabolic burden and in all cases, raises the risk of NAFLD, while intake of coffee and tea has decreased this risk without any significant adverse effects. In some cases, low to moderate alcohol intake has been shown to minimize the risk of advanced fibrosis and NAFLD-mortality.

CONCLUSION

Together, this review discusses and supports work on new dietary approaches and clinical studies to accomplish nutrition-oriented NAFLD care by improving the drinking habits.

Liver inflammation at the time of spinal cord injury enhances intraspinal pathology, liver injury, metabolic syndrome and locomotor deficits

The current high obesity rates mean that neurological injuries are increasingly sustained on a background of systemic pathology, including liver inflammation, which likely has a negative impact on outcomes. Because obesity involves complex pathology, the effect of hepatic inflammation alone on neurological recovery is unknown. Thus, here we used a gain-of-function model to test if liver inflammation worsens outcome from spinal cord injury (SCI) in rats. Results show liver inflammation concomitant with SCI exacerbated intraspinal pathology and impaired locomotor recovery. Hepatic inflammation also potentiated SCI-induced non-alcoholic steatohepatitis (NASH), endotoxemia and insulin resistance. Circulating and cerebrospinal levels of the liver-derived protein Fetuin-A were higher in SCI rats with liver inflammation, and, when microinjected into intact spinal cords, Fetuin-A caused macrophage activation and neuron loss. Thus, liver inflammation functions as a disease modifying factor to impair recovery from SCI, and Fetuin-A is a potential neuropathological mediator. Since SCI alone induces acute liver inflammation, the liver may be a novel clinical target for improving recovery from SCI.

Catechin-Rich Green Tea Extract and the Loss-of-TLR4 Signaling Differentially Alter the Hepatic Metabolome in Mice with Nonalcoholic Steatohepatitis

SCOPE

Catechin-rich green tea extract (GTE) limits inflammation in nonalcoholic steatohepatitis (NASH) consistent with a Toll-like receptor 4 (TLR4)-dependent mechanism. It is hypothesized that GTE supplementation during NASH will shift the hepatic metabolome similar to that attributed to the loss-of-TLR4 signaling.

METHODS AND RESULTS

Wild-type (WT) and loss-of-function TLR4-mutant (TLR4mut ) mice are fed a high-fat diet containing 0% or 2% GTE for 8 weeks prior to performing untargeted mass spectrometry-based metabolomics on liver tissue. The loss-of-TLR4 signaling and GTE shift the hepatic metabolome away from that of WT mice. However, relatively few metabolites are altered by GTE in WT mice to the same extent as the loss-of-TLR4 signaling in TLR4mut mice. GTE increases acetyl-coenzyme A precursors and spermidine to a greater extent than the loss-of-TLR4 signaling. Select metabolites associated with thiol metabolism are similarly affected by GTE and the loss-of-TLR4 signaling. Glycerophospholipid catabolites are decreased by GTE, but are unaffected in TLR4mut mice. Conversely, the loss-of-TLR4 signaling but not GTE increases several bile acid metabolites.

CONCLUSION

GTE limitedly alters the hepatic metabolome consistent with a TLR4-dependent mechanism. This suggests that the anti-inflammatory activities of GTE and loss-of-TLR4 signaling that regulate hepatic metabolism to abrogate NASH are likely due to distinct mechanisms.

Effects of Standardized Green Tea Extract and Its Main Component, EGCG, on Mitochondrial Function and Contractile Performance of Healthy Rat Cardiomyocytes

We recently showed that the long-term in vivo administration of green tea catechin extract (GTE) resulted in hyperdynamic cardiomyocyte contractility. The present study investigates the mechanisms underlying GTE action in comparison to its major component, epigallocatechin-3-gallate (EGCG), given at the equivalent amount that would be in the entirety of GTE. Twenty-six male Wistar rats were given 40 mL/day of a tap water solution with either standardized GTE or pure EGCG for 4 weeks. Cardiomyocytes were then isolated for the study. Cellular bioenergetics was found to be significantly improved in both GTE- and EGCG-fed rats compared to that in controls as shown by measuring the maximal mitochondrial respiration rate and the cellular ATP level. Notably, the improvement of mitochondrial function was associated with increased levels of oxidative phosphorylation complexes, whereas the cellular mitochondrial mass was unchanged. However, only the GTE supplement improved cardiomyocyte mechanics and intracellular calcium dynamics, by lowering the expression of total phospholamban (PLB), which led to an increase of both the phosphorylated-PLB/PLB and the sarco-endoplasmic reticulum calcium ATPase/PLB ratios. Our findings suggest that GTE might be a valuable adjuvant tool for counteracting the occurrence and/or the progression of cardiomyopathies in which mitochondrial dysfunction and alteration of intracellular calcium dynamics constitute early pathogenic factors.

Alleviation of Metabolic Endotoxemia by Milk Fat Globule Membrane: Rationale, Design, and Methods of a Double-Blind, Randomized, Controlled, Crossover Dietary Intervention in Adults with Metabolic Syndrome

BACKGROUND

Milk fat globule membrane (MFGM) is a phospholipid-rich component of dairy fat that might explain the benefits of full-fat dairy products on cardiometabolic risk. Preclinical studies support that MFGM decreases gut permeability, which could attenuate gut-derived endotoxin translocation and consequent inflammatory responses that impair cardiometabolic health.

OBJECTIVES

To describe the rationale, study design, and planned outcomes that will evaluate the efficacy of MFGM-enriched milk compared with a comparator beverage on health-promoting gut barrier functions in persons with metabolic syndrome (MetS).

METHODS

We plan a double-blind, randomized, crossover trial in which people with MetS will receive a rigorously controlled eucaloric diet for 2 wk that contains 3 daily servings of an MFGM-enriched bovine milk beverage or a comparator beverage that is formulated with nonfat dairy powder, coconut and palm oils, and soy phospholipids. Compliance will be monitored by assessing urinary para-aminobenzoic acid that is added to all test beverages. After the intervention, participants will ingest a high-fat/high-carbohydrate meal challenge to assess metabolic excursions at 30-min intervals for 3 h. Nondigestible sugar probes also will be ingested prior to collecting 24-h urine to assess region-specific gut permeability. Intervention efficacy will be determined based on circulating endotoxin (primary outcome) and glycemia (secondary outcome). Tertiary outcomes include: gut and systemic inflammatory responses, microbiota composition and SCFAs, gut permeability, and circulating insulin and incretins.

EXPECTED RESULTS

MFGM is expected to decrease circulating endotoxin and glycemia without altering body mass. These improvements are anticipated to be accompanied by decreased gut permeability, decreased intestinal and circulating biomarkers of inflammation, increased circulating incretins, and beneficial antimicrobial and prebiotic effects in the gut microbiome.

CONCLUSIONS

Demonstration of improvements in gut barrier functions that limit endotoxemia and glycemia could help to establish direct evidence that full-fat dairy lowers cardiometabolic risk, especially in people with MetS.The clinical trial associated with this article has been registered at clinicaltrials.gov (NCT03860584).

Toll-like Receptors as a Novel Therapeutic Target for Natural Products Against Chronic Diseases

Toll-like receptors (TLR) are one among the initial responders of the immune system which participate in the activation inflammatory processes. Several different types of TLR such as TLR2, TLR4, TLR7 and TLR9 have been identified in various cell types, each having distinct ligands like lipids, lipoproteins, nucleic acids and proteins. Though its prime concern is xenobiotic defences, TLR signalling has also recognized as an activator of inflammation and associated development of chronic degenerative disorders (CDDs) including obesity, type 2 diabetes mellitus (T2DM), fatty liver disease, cardiovascular and neurodegenerative disorders as well as various types of cancers. Numerous drugs are in use to prevent these disorders, which specifically inhibit different pathways associated with the development of CDDs. Compared to these drug targets, inhibition of TLR, which specifically responsible for the inflammatory insults has proven to be a better drug target. Several natural products have emerged as inhibitors of CDDs, which specifically targets TLR signalling, among these, many are in the clinical trials. This review is intended to summarize the recent progress on TLR association with CDDs and to list possible use of natural products, their combinations and their synthetic derivative in the prevention of TLR-driven CDD development.

Anti-inflammatory activities of green tea catechins along the gut-liver axis in nonalcoholic fatty liver disease: lessons learned from preclinical and human studies

Nonalcoholic fatty liver disease (NAFLD), which is the most prevalent hepatic disorder worldwide, affecting 25% of the general population, describes a spectrum of progressive liver conditions ranging from relatively benign liver steatosis and advancing to nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. Hallmark features of NASH are fatty hepatocytes and inflammatory cell infiltrates in association with increased activation of hepatic nuclear factor kappa-B (NFκB) that exacerbates liver injury. Because no pharmacological treatments exist for NAFLD, emphasis has been placed on dietary approaches to manage NASH risk. Anti-inflammatory bioactivities of catechin-rich green tea extract (GTE) have been well-studied, especially in preclinical models that have detailed its effects on inflammatory responses downstream of NFκB activation. This review will therefore discuss the experimental evidence that has advanced an understanding of the mechanisms by which GTE, either directly through its catechins or potentially indirectly through microbiota-derived metabolites, limits NFκB activation and NASH-associated liver injury. Specifically, it will describe the hepatic-level benefits of GTE that attenuate intracellular redox distress and pro-inflammatory signaling from extracellular receptors that otherwise activate NFκB. In addition, it will discuss the anti-inflammatory activities of GTE on gut barrier function as well as prebiotic and antimicrobial effects on gut microbial ecology that help to limit the translocation of gut-derived endotoxins (e.g. lipopolysaccharides) to the liver where they otherwise upregulate NFκB activation by Toll-like receptor-4 signaling. This summary is therefore expected to advance research translation of the hepatic- and intestinal-level benefits of GTE and its catechins to help manage NAFLD-associated morbidity.

Epigallocatechin gallate but not catechin prevents nonalcoholic steatohepatitis in mice similar to green tea extract while differentially affecting the gut microbiota

Catechin-rich green tea extract (GTE) protects against nonalcoholic steatohepatitis (NASH) by alleviating gut-derived endotoxin translocation and hepatic Toll-like receptor-4 (TLR4)-nuclear factor κB (NFκB) inflammation. We hypothesized that intact GTE would attenuate NASH-associated responses along the gut-liver axis to a greater extent than purified (-)-epigallocatechin gallate (EGCG) or (+)-catechin (CAT). Male C57BL/6J mice were fed a low-fat diet, a high-fat (HF) diet, or the HF diet with 2% GTE, 0.3% EGCG or 0.3% CAT for 8 weeks prior to assessing NASH relative to endotoxemia, hepatic and intestinal inflammation, intestinal tight junction proteins (TJPs) and gut microbial ecology. GTE prevented HF-induced obesity to a greater extent than EGCG and CAT, whereas GTE and EGCG more favorably attenuated insulin resistance. GTE, EGCG and CAT similarly attenuated serum alanine aminotransferase and serum endotoxin, but only GTE and EGCG fully alleviated HF-induced NASH. However, hepatic TLR4/NFκB inflammatory responses that were otherwise increased in HF mice were similarly attenuated by GTE, EGCG and CAT. Each treatment also similarly prevented the HF-induced loss in expression of intestinal TJPs and hypoxia inducible factor-1α and the otherwise increased levels of ileal and colonic TNFα mRNA and fecal calprotectin protein concentrations. Gut microbial diversity that was otherwise lowered in HF mice was maintained by GTE and CAT only. Further, microbial metabolic functions were more similar between GTE and CAT. Collectively, GTE catechins similarly protect against endotoxin-TLR4-NFκB inflammation in NASH, but EGCG and CAT exert differential prebiotic and antimicrobial activities suggesting that catechin-mediated shifts in microbiota composition are not entirely responsible for their benefits along the gut-liver axis.

Modulation of Glucose Metabolism by Leaf Tea Constituents: A Systematic Review of Recent Clinical and Pre-clinical Findings

Leaf teas are widely used as a purported treatment for dysregulated glucose homeostasis. The objective of this study was to systematically evaluate the clinical and cellular-metabolic evidence, published between January 2013 and May 2019, and indexed on PubMed, ScienceDirect, and Web of Science, supporting the use of leaf teas for this purpose. Fourteen randomized controlled trials (RCTs) (13 on Camellia sinensis teas) were included, with mixed results, and providing scant mechanistic information. In contrast, 74 animal and cell culture studies focusing on the pancreas, liver, muscle, and adipose tissue yielded mostly positive results and highlighted enhanced insulin signaling as a recurring target associated with the effects of teas on glucose metabolism. We conclude that more studies, including RCTs and pre-clinical studies examining teas from a wider variety of species beyond C. sinensis, are required to establish a stronger evidence base on the use of leaf teas to normalize glucose metabolism.

Intestinal-level anti-inflammatory bioactivities of catechin-rich green tea: Rationale, design, and methods of a double-blind, randomized, placebo-controlled crossover trial in metabolic syndrome and healthy adults

Metabolic endotoxemia initiates low-grade chronic inflammation in metabolic syndrome (MetS) and provokes the progression towards more advanced cardiometabolic disorders. Our recent works in obese rodent models demonstrate that catechin-rich green tea extract (GTE) improves gut barrier integrity to alleviate the translocation of gut-derived endotoxin and its consequent pro-inflammatory responses mediated through Toll-like receptor-4/nuclear factor κB (TLR4/NFκB) signaling. The objective of this clinical trial is to establish the efficacy of GTE to alleviate metabolic endotoxemia-associated inflammation in persons with MetS by improving gut barrier function. We plan a double-blind, placebo-controlled cross-over trial in persons with MetS and age- and gender-matched healthy persons (18-65 y; n = 20/group) who will receive a low-energy GTE-rich (1 g/day; 890 mg total catechins) confection snack food while following a low-polyphenol diet for 28 days. Assessments will include measures of circulating endotoxin (primary outcome) and secondary outcomes including biomarkers of endotoxin exposure, region-specific measures of intestinal permeability, gut microbiota composition, diversity, and functions, intestinal and systemic inflammatory responses, and catechins and microbiota-derived catechin metabolites. Study outcomes will provide the first report of the GTE-mediated benefits that alleviate gut barrier dysfunction in relation to endotoxemia-associated inflammation in MetS persons. This is expected to help establish an effective dietary strategy to mitigate the growing burden of MetS that currently affects ~35% of Americans.

Green tea extract inhibits early oncogenic responses in mice with nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) increases hepatocellular carcinoma (HCC) risk. We hypothesized that the hepatoprotective anti-inflammatory benefits of catechin-rich green tea extract (GTE) would protect against HCC progression by inhibiting NASH-associated liver injury and pro-oncogenic responses. We used an HCC model in high-fat (HF)-fed mice that mimics early oncogenic events during NASH without inducing tumorigenesis and premature mortality. Male C57BL/6J mice (4-weeks old) were fed a HF diet containing GTE at 0% or 2%. Mice were administered saline or diethylnitrosamine (DEN; 60 mg kg-1, i.p.) at 5-weeks and 7-weeks of age. NASH, inflammation, fibrosis, and oncogenic responses were assessed at 25-weeks of age. Saline-treated mice showed prominent histopathological signs of steatosis and hepatocellular ballooning. Although DEN did not impact adiposity, steatosis, ballooning and hepatic lipid accumulation, these parameters were attenuated by GTE regardless of DEN. Hepatic lipid peroxidation and fibrosis that were increased by DEN were attenuated by GTE. Hepatic TLR4, MCP1 and TNFα mRNA levels were unaffected by DEN, whereas iNOS was increased by DEN. These transcripts were lowered by GTE. GTE attenuated the frequency of PCNA+ hepatocytes and mRNA expression of cyclin D1, MIB1 and Ki-67 that were otherwise increased by DEN. GTE increase APAF1 mRNA that was otherwise lowered by DEN. Relative to saline-treated mice, DEN increased mRNA levels of oncostatin M, gp130, c-Fos, c-Myc and survivin; each was lowered by GTE in DEN-treated mice. These findings indicate that GTE may protect against hepatic oncogenesis by limiting early steps in the carcinogenic cascade related to NASH-associated HCC.

High-Fat Diet Aggravates the Intestinal Barrier Injury via TLR4-RIP3 Pathway in a Rat Model of Severe Acute Pancreatitis

OBJECTIVE

For patients with severe acute pancreatitis (SAP), a high body mass index (BMI) increases the possibility of infection derived from the intestine. In this study, we evaluate whether TAK242 can alleviate severe acute pancreatitis-associated injury of intestinal barrier in high-fat diet-fed rats.

METHODS

A SAP model was established by retrograde injection of 5% sodium taurocholate into the biliary-pancreatic duct. Thirty Sprague-Dawley (SD) adult rats were randomly divided into five groups: standard rat chow (SRC) normal (SN), SRC SAP (SAP), high-fat diet normal (HN), HFD SAP (HSAP), and TLR4 inhibitor pretreatment HFD SAP (HAPT) groups. Intraperitoneal injection of 3 mg/kg TAK242 was administered 30 minutes before SAP model establishment in the HAPT group. Rats were sacrificed 12 hours after SAP modeling, followed by blood and pancreatic and distal ileum tissue collection for further analyses. Changes in the pathology responses of the rats in each group were assessed.

RESULT

Analyses of serum amylase, lipase, cholesterol, triglyceride, IL-1β, IL-6, DAO, and serum endotoxin as well as tight junction protein expression including zonula occluden-1 and occludin indicated that high-fat diet aggravated SAP-induced intestinal barrier injury via increasing inflammatory response. In addition, the level of necroptosis was significantly higher in the SAP group compared with the SN group while the HSAP group exhibited more necroptosis compared with the SAP group, indicating the important role of necroptosis in pancreatitis-associated gut injury and illustrating that high-fat diet aggravated necroptosis of the ileum. Pretreatment with TLR4 inhibitor significantly alleviated inflammatory response and reduced necroptosis and level of oxidative stress while improving intestinal barrier function.

CONCLUSION

High-fat diet aggravated SAP-induced intestinal barrier injury via inflammatory reactions, necroptosis, and oxidative stress. Inhibition of TLR4 by TAK242 reduced inflammation, alleviated necroptosis, and lowered the level of oxidative stress and then protected the intestinal barrier dysfunction from SAP in high-fat diet-fed rats.

An Isocaloric Nordic Diet Modulates RELA and TNFRSF1A Gene Expression in Peripheral Blood Mononuclear Cells in Individuals with Metabolic Syndrome-A SYSDIET Sub-Study

A healthy dietary pattern is associated with a lower risk of metabolic syndrome (MetS) and reduced inflammation. To explore this at the molecular level, we investigated the effect of a Nordic diet (ND) on changes in the gene expression profiles of inflammatory and lipid-related genes in peripheral blood mononuclear cells (PBMCs) of individuals with MetS. We hypothesized that the intake of an ND compared to a control diet (CD) would alter the expression of inflammatory genes and genes involved in lipid metabolism. The individuals with MetS underwent an 18/24-week randomized intervention to compare a ND with a CD. Eighty-eight participants (66% women) were included in this sub-study of the larger SYSDIET study. Fasting PBMCs were collected before and after the intervention and changes in gene expression levels were measured using TaqMan Array Micro Fluidic Cards. Forty-eight pre-determined inflammatory and lipid related gene transcripts were analyzed. The expression level of the gene tumor necrosis factor (TNF) receptor superfamily member 1A (TNFRSF1A) was down-regulated (p = 0.004), whereas the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) subunit, RELAproto-oncogene, was up-regulated (p = 0.016) in the ND group compared to the CD group. In conclusion, intake of an ND in individuals with the MetS may affect immune function.

Green Tea Extract Treatment in Obese Mice with Nonalcoholic Steatohepatitis Restores the Hepatic Metabolome in Association with Limiting Endotoxemia-TLR4-NFκB-Mediated Inflammation

SCOPE

Catechin-rich green tea extract (GTE) alleviates nonalcoholic steatohepatitis (NASH) by lowering endotoxin-TLR4 (Toll-like receptor-4)-NFκB (nuclear factor kappa-B) inflammation. This study aimed to define altered MS-metabolomic responses during high-fat (HF)-induced NASH that are restored by GTE utilizing livers from an earlier study in which GTE decreased endotoxin-TLR4-NFκB liver injury.

METHODS AND RESULTS

Mice are fed a low-fat (LF) or HF diet for 12 weeks and then randomized to LF or HF diets containing 0% or 2% GTE for an additional 8 weeks. Global MS-based metabolomics and targeted metabolite profiling of catechins/catechin metabolites are evaluated. GTE in HF mice restores hepatic metabolites implicated in dyslipidemia insulin resistance, and inflammation. These include 122 metabolites: amino acids, lipids, nucleotides, vitamins, bile acids, flavonoids, xenobiotics, and carbohydrates. Hepatic amino acids, B-vitamins, and bile acids are inversely correlated with biomarkers of insulin resistance, liver injury, steatosis, and inflammation. Further, phosphatidylcholine metabolites are positively correlated with biomarkers of liver injury and NFκB inflammation. Thirteen catechin metabolites are identified in livers of GTE-treated mice, mostly as phase II conjugates of parental catechins or microbial-derived valerolactones.

CONCLUSION

The defined anti-inflammatory/metabolic interactions advance an understanding of the mechanism by which GTE catechins protect against NFκB-mediated liver injury in NASH.

Tea and Its Components Prevent Cancer: A Review of the Redox-Related Mechanism

Cancer is a worldwide epidemic and represents a major threat to human health and survival. Reactive oxygen species (ROS) play a dual role in cancer cells, which includes both promoting and inhibiting carcinogenesis. Tea remains one of the most prevalent beverages consumed due in part to its anti- or pro-oxidative properties. The active compounds in tea, particularly tea polyphenols, can directly or indirectly scavenge ROS to reduce oncogenesis and cancerometastasis. Interestingly, the excessive levels of ROS induced by consuming tea could induce programmed cell death (PCD) or non-PCD of cancer cells. On the basis of illustrating the relationship between ROS and cancer, the current review discusses the composition and efficacy of tea including the redox-relative (including anti-oxidative and pro-oxidative activity) mechanisms and their role along with other components in preventing and treating cancer. This information will highlight the basis for the clinical utilization of tea extracts in the prevention or treatment of cancer in the future.

A Comprehensive Insight on the Health Benefits and Phytoconstituents of Camellia sinensis and Recent Approaches for Its Quality Control

Tea, Camellia sinensis, which belongs to the family Theaceae, is a shrub or evergreen tree up to 16 m in height. Green tea is very popular because of its marked health benefits comprising its anticancer, anti-oxidant, and antimicrobial activities, as well as its effectiveness in reducing body weight. Additionally, it was recognized by Chinese people as an effective traditional drink required for the prophylaxis against many health ailments. This is due to the complex chemical composition of green tea, which comprises different classes of chemical compounds, such as polyphenols, alkaloids, proteins, minerals, vitamins, amino acids, and others. The beneficial health effects of green tea ultimately led to its great consumption and increase its liability to be adulterated by either low-quality or non-green tea products with concomitant decrease in activity. Thus, in this review, green tea was selected to highlight its health benefits and phytoconstituents, as well as recent approaches for its quality-control monitoring that guarantee its incorporation in many pharmaceutical industries. More research is needed to find out other more biological activities, active constituents, and other simple and cheap techniques for its quality assurance that ascertain the prevention of its adulteration.

Correlation Analysis of Intestinal Redox State with the Gut Microbiota Reveals the Positive Intervention of Tea Polyphenols on Hyperlipidemia in High Fat Diet Fed Mice

Tea polyphenols (TP) possess the ability to regulate dyslipidemia and gut microbiota dysbiosis. However, the underlying mechanism is still elusive. The present study explored the intervention of TP on high fat diet induced metabolic disorders, gut microbiota dysbiosis in mice, and the underlying intestinal mechanism. As a result, TP significantly ameliorated hyperlipidemia, improved the expression levels of hepatic lipid metabolism genes, and modulated gut microbiota. The underlying mechanism was supposed to rely on the maintaining of intestinal redox state by TP. Intestinal redox related indicators were significantly correlated with the distribution of gut microbiota. An unidentified genus of Lachnospiraceae, Bacteroides, Alistipes, and Faecalibaculum were identified as the biomarkers for intestinal redox state. Importantly, different dosages of TP modulated intestinal redox state and gut microbiota in varied patterns, and an overdose intake attenuated the beneficial effects on gut health. Our findings offered novel insights into the mechanism of TP on intestinal homeostasis.

Preventive Efficiency of Green Tea and Its Components on Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a typical chronic liver disease highly correlated with metabolic syndrome. Growing prevalence of NAFLD is supposed to be linked with the unhealthy lifestyle, especially high-calorie diet and lacking enough exercise. Currently, there is no validated pharmacological therapy for NAFLD except for weight reduction. However, many dietary strategies had preventive effects on the development of liver steatosis or its progression. As one of the most common beverages, green tea contains abundant bioactive compounds possessing antioxidant, lipid-lowering, and anti-inflammatory effects, as well as improving insulin resistance and gut dysbiosis that can alleviate the risk of NAFLD. Hence, in this review, we summarized the studies of green tea and its components on NAFLD from animal experiments and human interventions and discussed the potential mechanisms. Available evidence suggested that tea consumption is promising to prevent NAFLD, and further mechanisms and clinical studies need to be investigated.

Green tea extract prevents obesity in male mice by alleviating gut dysbiosis in association with improved intestinal barrier function that limits endotoxin translocation and adipose inflammation

Gut-derived endotoxin translocation provokes obesity by inducing TLR4/NFκB inflammation. We hypothesized that catechin-rich green tea extract (GTE) would protect against obesity-associated TLR4/NFκB inflammation by alleviating gut dysbiosis and limiting endotoxin translocation. Male C57BL/6J mice were fed a low-fat (LF) or high-fat (HF) diet containing 0% or 2% GTE for 8 weeks. At Week 7, fluorescein isothiocyanate (FITC)-dextran was administered by oral gavage before assessing its serum concentrations as a gut permeability marker. HF-feeding increased (P<.05) adipose mass and adipose expression of genes involved in TLR4/NFκB-dependent inflammation and macrophage activation. GTE attenuated HF-induced obesity and pro-inflammatory gene expression. GTE in HF mice decreased serum FITC-dextran, and attenuated portal vein and circulating endotoxin concentrations. GTE in HF mice also prevented HF-induced decreases in the expression of intestinal tight junction proteins (TJPs) and hypoxia inducible factor-1α while preventing increases in TLR4/NFκB-dependent inflammatory genes. Gut microbial diversity was increased, and the Firmicutes:Bacteroidetes ratio was decreased, in HF mice fed GTE compared with HF controls. GTE in LF mice did not attenuate adiposity but decreased endotoxin and favorably altered several gut bacterial populations. Serum FITC-dextran was correlated with portal vein endotoxin (P<.001; r_P=0.66) and inversely correlated with colonic mRNA levels of TJPs (P<.05; r_P=-0.38 to -0.48). Colonic TJPs mRNA were inversely correlated with portal endotoxin (P<.05; r_P=-0.33 to -0.39). These data suggest that GTE protects against diet-induced obesity consistent with a mechanism involving the gut-adipose axis that limits endotoxin translocation and consequent adipose TLR4/NFκB inflammation by improving gut barrier function.

The relationship between vitamin C status, the gut-liver axis, and metabolic syndrome

Metabolic syndrome (MetS) is a constellation of cardiometabolic risk factors, which together predict increased risk of more serious chronic diseases. We propose that one consequence of dietary overnutrition is increased abundance of Gram-negative bacteria in the gut that cause increased inflammation, impaired gut function, and endotoxemia that further dysregulate the already compromised antioxidant vitamin status in MetS. This discussion is timely because "healthy" individuals are no longer the societal norm and specialized dietary requirements are needed for the growing prevalence of MetS. Further, these lines of evidence provide the foundational basis for investigation that poor vitamin C status promotes endotoxemia, leading to metabolic dysfunction that impairs vitamin E trafficking through a mechanism involving the gut-liver axis. This report will establish a critical need for translational research aimed at validating therapeutic approaches to manage endotoxemia-an early, but inflammation-inducing phenomenon, which not only occurs in MetS, but is also prognostic of more advanced metabolic disorders including type 2 diabetes mellitus, as well as the increasing severity of nonalcoholic fatty liver diseases.

When to Initiate Weight Loss Medications in the NAFLD Population

Nonalcoholic fatty liver disease (NAFLD) is characterized by histological evidence of hepatic steatosis, lobular inflammation, ballooning degeneration and hepatic fibrosis in the absence of significant alcohol use and other known causes of chronic liver diseases. NAFLD is subdivided into nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH). NAFL is generally benign but can progress to NASH, which carries a higher risk of adverse outcomes including cirrhosis, end-stage liver disease, hepatocellular carcinoma and death if liver transplantation is not pursued in a timely fashion. Currently, lifestyle modifications including healthy diet and increased physical activity/exercise culminating in weight loss of 5% to >10% is the cornerstone of treatment intervention for patients with NAFLD. Patients with NAFLD who fail to obtain this goal despite the help of dietitians and regimented exercise programs are left in a purgatory state and remain at risk of developing NASH-related advance fibrosis. For such patients with NAFLD who are overweight and obese, healthcare providers should consider a trial of FDA-approved anti-obesity medications as adjunct therapy to provide further preventative and therapeutic options as an effort to reduce the risk of NAFLD-related disease progression.

Dietary Green Tea Extract Prior to Spinal Cord Injury Prevents Hepatic Iron Overload but Does Not Improve Chronic Hepatic and Spinal Cord Pathology in Rats

Spinal cord injury (SCI) disrupts autonomic regulation of visceral organs. As a result, a leading cause of mortality in the SCI population is metabolic dysfunction, and an organ central to metabolic control is the liver. Our recent work showed that rodent SCI promotes Kupffer cell (hepatic macrophage) activation, pro-inflammatory cytokine expression, and liver steatosis. These are symptoms of nonalcoholic steatohepatitis (NASH), the hepatic manifestation of metabolic syndrome, and these pre-clinical data replicate aspects of post-SCI human metabolic dysfunction. Because metabolic profile is highly dependent on lifestyle, including diet, it is likely that lifestyle choices prior to injury influence metabolic and hepatic outcomes after SCI. Therefore, in this study we tested if a diet rich in green tea extract (GTE), a known hepatoprotective agent, that began 3 weeks before SCI and was maintained after injury, reduced indices of liver pathology or metabolic dysfunction. GTE treatment significantly reduced post-SCI hepatic iron accumulation and blunted circulating glucose elevation compared with control-diet rats. However, GTE pre-treatment did not prevent Kupffer cell activation, hepatic lipid accumulation, increased serum alanine transaminase, or circulating non-esterified fatty acids, which were all significantly increased 6 weeks post-injury. Spinal cord pathology also was unchanged by GTE. Thus, dietary GTE prior to and after SCI had only a minor hepatoprotective effect. In general, for optimal health of SCI individuals, it will be important for future studies to evaluate how other lifestyle choices made before or after SCI positively or negatively impact systemic and intraspinal outcomes and the overall metabolic health of SCI individuals.

Potential Therapeutic Benefits of Herbs and Supplements in Patients with NAFLD

Our aim is to review the efficacy of various herbs and supplements as a possible therapeutic option in the treatment and/or prevention of nonalcoholic fatty liver disease (NAFLD). We performed a systematic review of medical literature using the PubMed Database by searching the chemical names of many common herbs and supplements with “AND (NAFLD or NASH)”. Studies and medical literature that discussed the roles and usage of herbs and supplements in NAFLD and nonalcoholic steatohepatitis (NASH) from inception until 20 June 2018 were reviewed. Many studies have claimed that the use of various herbs and supplements may improve disease endpoints and outcomes related to NAFLD and/or NASH. Improvement in liver function tests were noted. Amelioration or reduction of lobular inflammation, hepatic steatosis, and fibrosis were also noted. However, well-designed studies demonstrating improved clinical outcomes are lacking. Furthermore, experts remain concerned about the lack of regulation of herbs/supplements and the need for further research on potential adverse effects and herb–drug interactions. In conclusion, preliminary data on several herbs have demonstrated promising antioxidant, anti-inflammatory, anti-apoptotic, and anti-adipogenic properties that may help curtail the progression of NAFLD/NASH. Clinical trials testing the safety and efficacy must be completed before widespread use can be recommended.

Premeal Low-Fat Yogurt Consumption Reduces Postprandial Inflammation and Markers of Endotoxin Exposure in Healthy Premenopausal Women in a Randomized Controlled Trial

Background

Metabolic endotoxemia is associated with obesity and contributes to postprandial inflammation.

Objective

We aimed to determine if low-fat yogurt consumption prevents postprandial inflammation and dysmetabolism in healthy women by inhibiting biomarkers of metabolic endotoxemia.

Methods

Premenopausal women defined as obese and nonobese [body mass index (BMI, in kg/m2) 30-40 and 18.5-27, respectively, n = 120] were randomly assigned to consume 339 g of low-fat yogurt (YN, yogurt nonobese; YO, yogurt obese) or 324 g of soy pudding (CN, control nonobese; CO, control obese) for 9 wk (n = 30/group). The intervention foods each supplied 330 kcal with 3 g fat, 66 g carbohydrate, and 4-6 g protein. At weeks 0 and 9, participants ingested 226 g of yogurt or 216 g of soy pudding before a meal providing 56-60 g fat, 82 g carbohydrate, and 28-30 g protein. Plasma soluble CD14 (sCD14), lipopolysaccharide-binding protein (LBP), LPS activity, interleukin-6 (IL-6), glucose, triglyceride, and insulin were measured hourly for 4 h to assess differences in postprandial responses between groups by 2-factor ANOVA.

Results

Premeal yogurt consumption prevented the postprandial decrease in sCD14 net incremental area under the curve (net iAUC) by 72% in obese individuals at week 0 (P = 0.0323). YN and YO had ≥40% lower net iAUC of LBP-to-sCD14 ratio and plasma IL-6 concentration than CN and CO, respectively (P < 0.05). CO had postprandial hyperglycemia which was not evident in YO; in contrast YN had 57% less postprandial hypoglycemia than did CN (P-interaction = 0.0013). After 9 wk of yogurt consumption, ΔAUC of LBP-to-sCD14 ratios of YO and YN were less than half of those of the control groups (P = 0.0093).

Conclusion

Yogurt consumption improved postprandial metabolism and biomarkers of metabolic endotoxemia in healthy premenopausal women. Premeal yogurt consumption is a feasible strategy to inhibit postprandial dysmetabolism and thus may reduce cardiometabolic risk. This trial was registered at clinicaltrials.gov as NCT01686204.

Green tea extract protects against hepatic NFκB activation along the gut-liver axis in diet-induced obese mice with nonalcoholic steatohepatitis by reducing endotoxin and TLR4/MyD88 signaling

Green tea extract (GTE) reduces NFκB-mediated inflammation during nonalcoholic steatohepatitis (NASH). We hypothesized that its anti-inflammatory activities would be mediated in a Toll-like receptor 4 (TLR4)-dependent manner. Wild-type (WT) and loss-of-function TLR4-mutant (TLR4m) mice were fed a high-fat diet containing GTE at 0 or 2% for 8 weeks before assessing NASH, NFκB-mediated inflammation, TLR4 and its adaptor proteins MyD88 and TRIF, circulating endotoxin, and intestinal tight junction protein mRNA expression. TLR4m mice had lower (P<.05) body mass compared with WT mice but similar adiposity, whereas body mass and adiposity were lowered by GTE regardless of genotype. Liver steatosis, serum alanine aminotransferase, and hepatic lipid peroxidation were also lowered by GTE in WT mice, and were similarly lowered in TLR4m mice regardless of GTE. Phosphorylation of the NFκB p65 subunit and pro-inflammatory genes (TNFα, iNOS, MCP-1, MPO) were lowered by GTE in WT mice, and did not differ from the lowered levels in TLR4m mice regardless of GTE. TLR4m mice had lower TLR4 mRNA, which was also lowered by GTE in both genotypes. TRIF expression was unaffected by genotype and GTE, whereas MyD88 was lower in mice fed GTE regardless of genotype. Serum endotoxin was similarly lowered by GTE regardless of genotype. Tight junction protein mRNA levels were unaffected by genotype. However, GTE similarly increased claudin-1 mRNA in the duodenum and jejunum and mRNA levels of occludin and zonula occluden-1 in the jejunum and ileum. Thus, GTE protects against inflammation during NASH, likely by limiting gut-derived endotoxin translocation and TLR4/MyD88/NFκB activation.