Oxidative Inactivation of Liver Mitochondria in High Fructose Diet-Induced Metabolic Syndrome in Rats: Effect of Glycyrrhizin Treatment

Glycyrrhizin Protects Submandibular Gland Against Radiation Damage by Enhancing Antioxidant Defense and Preserving Mitochondrial Homeostasis

Aims: Radiotherapy inevitably causes radiation damage to the salivary glands (SGs) in patients with head and neck cancers (HNCs). Excessive reactive oxygen species (ROS) levels and imbalanced mitochondrial homeostasis are serious consequences of ionizing radiation in SGs; however, there are few mitochondria-targeting therapeutic approaches. Glycyrrhizin is the main extract of licorice root and exhibits antioxidant activity to relieve mitochondrial damage in certain oxidative stress conditions. Herein, the effects of glycyrrhizin on irradiated submandibular glands (SMGs) and the related mechanisms were investigated. Results: Glycyrrhizin reduced radiation damage in rat SMGs at both the cell and tissue levels, and promoted saliva secretion in irradiated SMGs. Glycyrrhizin significantly downregulated high-mobility group box-1 protein (HMGB1) and toll-like receptor 5 (TLR5). Moreover, glycyrrhizin significantly suppressed the increases in malondialdehyde and glutathione disulfide (GSSG) levels; elevated the activity of some critical antioxidants, including superoxide dismutase, catalase, glutathione peroxidase, and glutathione (GSH); and increased the GSH/GSSG ratio in irradiated cells. Importantly, glycyrrhizin effectively enhanced thioredoxin-2 levels and scavenged mitochondrial ROS, inhibited the decline in mitochondrial membrane potential, improved adenosine triphosphate synthesis, preserved the mitochondrial ultrastructure, activated the proliferator-activated receptor-gamma coactivator-1alpha (PGC-1α)/nuclear respiratory factor 1/2 (NRF1/2)/mitochondrial transcription factor A (TFAM) signaling pathway, and inhibited mitochondria-related apoptosis in irradiated SMG cells and tissues. Innovation: Radiotherapy causes radiation sialadenitis in HNC patients. Our data suggest that glycyrrhizin could be a mitochondria-targeted antioxidant for the prevention of radiation damage in SGs. Conclusion: These findings demonstrate that glycyrrhizin protects SMGs from radiation damage by downregulating HMGB1/TLR5 signaling, maintaining intracellular redox balance, eliminating mitochondrial ROS, preserving mitochondrial homeostasis, and inhibiting apoptosis.

Natural Drugs: A New Direction for the Prevention and Treatment of Diabetes

Insulin resistance, as a common pathological process of many metabolic diseases, including diabetes and obesity, has attracted much attention due to its relevant influencing factors. To date, studies have mainly focused on the shared mechanisms between mitochondrial stress and insulin resistance, and they are now being pursued as a very attractive therapeutic target due to their extensive involvement in many human clinical settings. In view of the complex pathogenesis of diabetes, natural drugs have become new players in diabetes prevention and treatment because of their wide targets and few side effects. In particular, plant phenolics have received attention because of their close relationship with oxidative stress. In this review, we briefly review the mechanisms by which mitochondrial stress leads to insulin resistance. Moreover, we list some cytokines and genes that have recently been found to play roles in mitochondrial stress and insulin resistance. Furthermore, we describe several natural drugs that are currently widely used and give a brief overview of their therapeutic mechanisms. Finally, we suggest possible ideas for future research related to the unique role that natural drugs play in the treatment of insulin resistance through the above targets.

Linggui Zhugan Decoction activates the SIRT1-AMPK-PGC1α signaling pathway to improve mitochondrial and oxidative damage in rats with chronic heart failure caused by myocardial infarction

Objective: To investigate the effects of Linggui Zhugan Decoction on mitochondrial and oxidative damage in rats with chronic heart failure after myocardial infarction and the related mechanisms. Methods: Chronic heart failure after myocardial infarction was established by coronary artery ligation. Heart failure rats were randomly divided into three groups: Model group (n = 11), Linggui Zhugan Decoction group (n = 12), and captopril group (n = 11). Rats whose coronary arteries were only threaded and not ligated were sham group (n = 11). Cardiac function, superoxide dismutase (SOD), malondialdehyde (MDA) contents, soluble growth-stimulating expression factor (ST2), and N-terminal B-type brain natriuretic peptide precursor (NTproBNP) levels were analyzed after treatment. Moreover, the level of mitochondrial membrane potential was detected by JC-1 staining, the ultrastructural of myocardial mitochondria were observed by transmission electron microscopy. The related signal pathway of silent information regulator factor 2-related enzyme 1 (SIRT1), adenylate activated protein kinase (AMPK), phosphorylated adenylate activated protein kinase (p-AMPK), and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) is an important pathway to regulate mitochondrial energy metabolism, and to initiate mitochondrial biogenesis. The expression level was detected by Western blot and reverse transcription to explore the mechanism of the decoction. Results: Compared with the model rats, Linggui Zhugan Decoction significantly improved cardiac function (p < 0.05), reduced MDA production (p < 0.01), increased SOD activity (p < 0.05), reduced ST-2(p < 0.01), and NT-proBNP(p < 0.05) levels, increased mitochondrial membrane potential, and improved mitochondria function. In addition, Linggui Zhugan Decoction upregulated the expression of SIRT1, p-AMPK, PGC-1α protein, and mRNA in cardiac myocytes. Conclusion: Linggui Zhugan Decoction can improve the cardiac function of heart failure rats by enhancing myocardial antioxidant capacity and protecting the mitochondrial function, the mechanism is related to activating SIRT1/AMPK/PGC-1α signaling pathway.

An Ethnopharmaceutical Study on the Hypolipidemic Formulae in Taiwan Issued by Traditional Chinese Medicine Pharmacies

Globally, approximately one-third of ischemic heart diseases are due to hyperlipidemia, which has been shown to cause various metabolic disorders. This study was aimed to disassemble and analyze hypolipidemic formulae sold by traditional Chinese medicine (TCM) pharmacies. Using commonly used statistical parameters in ethnopharmacology, we identified the core drug combination of the hypolipidemic formulae, thereby exploring the strategy by which the Taiwanese people select hypolipidemic drugs. Most important of all, we preserved the inherited knowledge of TCM. We visited 116 TCM pharmacies in Taiwan and collected 91 TCM formulae. The formulae were mainly disassembled by macroscopical identification, and the medicinal materials with a relative frequency of citation (RFC) >0.2 were defined as commonly used medicinal materials. Subsequently, we sorted the information of medicinal materials recorded in the Pharmacopeia, searched for modern pharmacological research on commonly used medicinal materials using PubMed database, and visualized data based on the statistical results. Finally, the core hypolipidemic medicinal materials used in folk medicine were obtained. Of the 91 TCM formulae collected in this study, 80 traditional Chinese medicinal materials were used, belonging to 43 families, predominantly Lamiaceae. Roots were the most commonly used part as a medicinal material. There were 17 commonly used medicinal materials. Based on medicinal records in Pharmacopeia, most flavors and properties were warm and pungent, the majority traditional effects were “tonifying and replenishing” and “blood-regulating.” Besides, the targeted diseases searching from modern pharmacological studies were diabetes mellitus and dyslipidemia. The core medicinal materials consisted of Astragalus mongholicus Bunge and Crataegus pinnatifida Bunge, and the core formulae were Bu-Yang-Huan-Wu-Tang and Xie-Fu-Zhu-Yu-Tang. In addition, 7 groups of folk misused medicinal materials were found. Although these TCMs have been used for a long period of time, their hypolipidemic mechanisms remain unclear, and further studies are needed to validate their safety and efficacy.

Curcumin prevents proteins expression changes of oxidative phosphorylation, cellular stress response, and lipid metabolism proteins in liver of mice fed a high-fructose diet

Increased fructose consumption has been associated with the development of metabolic diseases due to the modification in protein expression, altering metabolic and signaling pathways. Curcumin is a natural compound with a regulatory effect on genes and metabolic pathways. To identify the fructose-induced protein expression changes and the effect of curcumin on the change of protein expression in the liver of mice fed a standard diet and a high fructose diet, to elucidate the global role of curcumin. Four groups (n = 4/group) of male mice (C57BL6J) of six-weeks-old were formed. One group received a standard diet (C); another received curcumin at 0.75% w/w in the feed (C + C); one more received 30% w/v fructose in drinking water (F); and one group received 30% w/v fructose in drinking water and 0.75% w/w curcumin in food (F + C); for 15 weeks. Proteomic analysis was performed by LC-MS/MS, using the label-free technique with the MaxQuant programs for identification and Perseus for expression change analysis. Differentially expressed proteins (fold change ≥1.5 and p < 0.5) were analyzed by gene ontology and KEGG. A total of 1047 proteins were identified, of which 113 changed their expression in mice fed fructose, compared to the control group, and curcumin modified the expression of 64 proteins in mice fed fructose and curcumin compared to mice that only received fructose. Curcumin prevented the change of expression of 13 proteins involved in oxidative phosphorylation (NDUFB8, NDUFB3, and ATP5L) in the cellular response to stress (PSMA5, HIST1H1D) and lipid metabolism (THRSP, DGAT1, ECI1, and ACOT13). Curcumin in mice fed the standard diet increased the expression of proteins related to oxidative phosphorylation, ribosomes, and PPAR pathways. In addition to fructose, increased expression of proteins involved in oxidative phosphorylation, ribosomes, lipid metabolism, and carbon metabolism. However, curcumin prevented expression change in 13 hepatic proteins of fructose-fed mice involved in oxidative phosphorylation, cellular stress response, and lipid metabolism. SIGNIFICANCE: Curcumin is a natural compound with a regulatory effect on proteins and metabolic pathways. So, curcumin prevents the change of expression in 13 hepatic proteins of fructose-fed mice involved in oxidative phosphorylation, cellular stress response and lipid metabolism, as a supplement with protector activity on fructose-induced toxic effects.

The hepatoprotective effects of plant-based foods based on the "gut-liver axis": a prospective review

The importance of the "gut-liver axis" in the pathogenesis of liver diseases has been revealed recently; which promotes the process of developing preventive and therapeutic strategies. However, considering that there are still many challenges in the medical treatment of liver diseases, potential preventive dietary intervention may be a good alternative choice. Plant-based foods have received much attention due to their reported health-promoting effects in targeting multiple pathways involved in the pathogenesis of liver diseases as well as the relative safety for general use. Based on the PubMed and Web of Science databases, this review emphatically summarizes the plant-based foods and their chemical constituents with reported effects to impact the LPS/TLR4 signaling pathway of gut-liver axis of various liver diseases, reflecting their health benefits in preventing/alleviating liver diseases. Moreover, some plant-based foods with potential gut-liver effects are specifically analyzed from the reported studies and conclusions. This review intends to provide readers an overview of the current progress in the field of this research topic. We expect to see more hepatoprotective measures for alleviating the current prevalence of liver diseases.

Glycyrrhizin Attenuates Hypoxic-Ischemic Brain Damage by Inhibiting Ferroptosis and Neuroinflammation in Neonatal Rats via the HMGB1/GPX4 Pathway

With unknown etiology and limited treatment options, neonatal hypoxic-ischemic brain damage (HIBD) remains a major cause of mortality in newborns. Ferroptosis, a recently discovered type of cell death triggered by lipid peroxidation, is closely associated with HIBD. High-mobility group box 1 (HMGB1), a molecule associated with inflammation damage, can induce neuronal death in HIBD. However, it remains unknown whether HMGB1 contributes to neuronal ferroptosis in patients with HIBD. Herein, glycyrrhizin (GL), an HMGB1 inhibitor, was used to investigate the relationship between ferroptosis and HMGB1. RAS-selective lethal 3(RSL3), a ferroptosis agonist, was administered to further confirm the changes in the signaling pathway between HMGB1 and ferroptosis. Western blot analysis revealed that GL markedly suppressed the expression of HMGB1 and increased the level of GPX4 in the context of HIBD. We observed changes in neuronal ultrastructure via transmission electron microscopy to further confirm the occurrence of ferroptosis. Real-time PCR indicated that GL inhibited the expression of ferroptosis-related genes and inflammatory factors. Immunofluorescence and immunohistochemistry staining confirmed GL inhibition of neuronal damage and ferroptosis in HIBD associated with GPX4 and ROS. GL not only inhibited ferroptosis induced by RSL3 and oxygen-glucose deprivation in vitro but also inhibited ferroptosis induced by HIBD in vivo. More importantly, GL may improve oxidative stress imbalance and mitochondrial damage, alleviate the downstream production of inflammatory factors, and ultimately reduce ferroptosis and damage to cortical neurons following HIBD via the HMGB1/GPX4 pathway. In conclusion, we showed for the first time that GL could suppress the occurrence of neuronal ferroptosis and reduce neuronal loss in HIBD via the HMGB1/GPX4 pathway. These findings highlight the potential of HMGB1 signaling antagonists to treat neuronal damage by suppressing ferroptosis, provide new and unique insights into GL as a neuroprotective agent, and suggest new prevention and treatment strategies for HIBD.

Natural and Synthetic Agents Targeting Reactive Carbonyl Species against Metabolic Syndrome

Reactive carbonyl species (RCS) may originate from the oxidation of unsaturated fatty acids and sugar in conditions of pathology. They are known to have high reactivity towards DNA as well as nucleophilic sites of proteins, resulting in cellular dysfunction. It has been considered that various pathological conditions are associated with an increased level of RCS and their reaction products. Thus, regulating the levels of RCS may be associated with the mitigation of various metabolic and neurodegenerative disorders. In order to perform a comprehensive review, various literature databases, including MEDLINE, EMBASE, along with Google Scholar, were utilized to obtain relevant articles. The voluminous review concluded that various synthetic and natural agents are available or in pipeline research that hold tremendous potential to be used as a drug of choice in the therapeutic management of metabolic syndrome, including obesity, dyslipidemia, diabetes, and diabetes-associated complications of atherosclerosis, neuropathy, and nephropathy. From the available data, it may be emphasized that various synthetic agents, such as carnosine and simvastatin, and natural agents, such as polyphenols and terpenoids, can become a drug of choice in the therapeutic management for combating metabolic syndromes that involve RCS in their pathophysiology. Since the RCS are known to regulate the biological processes, future research warrants detailed investigations to decipher the precise mechanism.

Fructose Consumption and Hepatocellular Carcinoma Promotion

Hepatocellular carcinoma (HCC) accounts for 85% of primary liver cancer, the third most common cause of cancer-related deaths worldwide. Its incidence has been increasing in both men and women. In Western countries, high-calorie diets, mainly rich in carbohydrates such as fructose, represent a significant concern due to their repercussions on the population’s health. A high-fructose diet is related to the development of Metabolic-Associated Fatty Liver Disease (MAFLD), formerly named Non-Alcoholic Fatty Liver Disease (NAFLD), and the progression of HCC as it potentiates the lipogenic pathway and the accumulation of lipids. However, fructose metabolism seems to be different between the stages of the disease, carrying out a metabolic reprogramming to favor the proliferation, inflammation, and metastatic properties of cancer cells in HCC. This review focuses on a better understanding of fructose metabolism in both scenarios: MAFLD and HCC.

Glycyrrhiza glabra alcoholic root extract ameliorates hyperglycemia, hyperlipidemia, and glycation-induced free iron-mediated oxidative reactions

Hyperglycemia-associated oxidative stress leads to various pathophysiological complications in diabetes mellitus. Here, the effects of Glycyrrhiza glabra (G. glabra) root extract of streptozotocin (STZ)-induced diabetic changes and the associated free iron-mediated oxidative reactions were investigated. The animals were divided into five group, Group 1: Control (NC received buffer); Group 2: STZ-induced (DC); Group 3: Control treated with G. glabra root extract (NT, 60 mg/Kg b.w daily for 1 month); Group 4: Diabetic treated with the extract (60 mg/Kg b.w daily for 1 month); Group 5: Diabetic treated with glibenclamide (DTG, 8.6 mg/Kg b.w for 1 month). STZ (i) induced hyperglycemia, abnormal intraperitoneal glucose tolerance test (IPGTT), increased HbA_1c and decreased plasma insulin levels (ii) hyperlipidemia (iii) lowered antioxidant enzyme activities (iv) diminished RBC membrane fluidity (v) enhanced hemoglobin glycation-induced iron release and associated free radical reactions. Treatment with the extract resulted in significant reversal of hyperglycemia (DC: 205.0 ± 7.0 mg/dl vs. DT: 87.5 ± 4.5 mg/dl, p < .05); HbA_1c (DC: 11.5 ± 2.0 vs. DT: 7.5 ± 0.8 vs. DT: 7.5 ± 0.8, p < .05); insulin (DC: 0.3 ± 0.06 vs. DT: 1.25 ± 0.15 μgm/L, p < .05); free iron (DC: 150.4 ± 7.07 vs. DT: 98.8 ± 7.7 μgm/gm of Hb, p < .05); TBARS (DC + H₂ O₂ : 24.62 ± 11.30 vs. DC + H₂ O₂ : 9.82 ± 2.56 mmoles/h, p < .05); carbonyl (DC: 40.40 ± 1.57 vs. DT: 25.50 ± 1.12 mmoles/g of Hb, p < .05) levels and β-cell count/pancreatic islet (DC: 85 ± 15 vs. DT: 125 ± 20, p < .05). Thus, G. glabra extract is quite effective against hyperglycemia and the associated free iron-mediated oxidative stress. PRACTICAL APPLICATIONS: Chronic use of oral hypoglycemic synthetic drugs may produce side effects and drug resistance. Recently, various plant extracts are being researched to explore their antihyperglycemic potential. Here, the effects of this alcoholic powdered root extract on STZ-induced diabetic changes and associated oxidative stress, including hemoglobin-induced free iron-mediated oxidative reactions were examined. The STZ-induced diabetic changes and hemoglobin-glycation-induced free iron-mediated oxidative reactions were alleviated in the Wistar rats after 1-month of treatment with the extract. We have also reported previously that glycyrrhizin, a bioactive constituent of Glycyrrhiza glabra root inhibits peroxidase, esterase activities of hemoglobin and hemoglobin-mediated oxidative damage without affecting oxygen-binding capacity of the protein. This preclinical work further substantiates the potential therapeutic use of the G. glabra whole root extract in the treatment of diabetes mellitus.

Development of rat metabolic syndrome models: A review

Metabolic syndrome (MetS) has become a global problem. With the increasing prevalence of MetS worldwide, understanding its pathogenesis and treatment modalities are essential. Animal models should allow an appropriate representation of the clinical manifestations of human conditions. Rats are the most commonly used experimental animals for the study. The development of a proper MetS model using rats will contribute to the successful application of research findings to the clinical setting. Various intervention methods are used to induce MetS through diet induction with various compositions, chemicals, or a combination of both. This review will provide a comprehensive overview of several studies on the development of rat MetS models, along with the characteristics of the clinical manifestations resulting from each study.

Advances in Pharmacological Activities and Mechanisms of Glycyrrhizic Acid

Licorice (Glycyrrhiza glabra L.) is widely regarded as an important medicinal plant and has been used for centuries in traditional medicine because of its therapeutic properties. Studies have shown that metabolites isolated from licorice have many pharmacological activities, such as antiinflammatory, anti-viral, participation in immune regulation, anti-tumor and other activities. This article gives an overview of the pharmacological activities and mechanisms of licorice metabolites and the adverse reactions that need attention. This review helps to further investigate the possibility of licorice as a potential drug for various diseases. It is hoped that this review can provide a relevant theoretical basis for relevant scholars' research and their own learning.

Diagnostic Criteria for Metabolic Syndrome in Diet-Induced Rodent Models: A Systematic Review

BACKGROUND

Thousands of publications in recent years have addressed the induction of metabolic syndrome (MetS) in rodents. However, the criteria and the reference values for diagnosing this disease have not been defined.

OBJECTIVE

Our main objective was to carry out a systematic review to gather evidence about the criteria for biochemical and anthropometric parameters in which scientific studies have relied on to report that rats developed MetS from a previous dietary manipulation.

METHODS

We compiled characteristics and findings of diet-induced MetS with high-fat, high-carbohydrate, high-fat/high-carbohydrates, and cafeteria diet from PubMed and Science Direct databases published in the last 5 years.

RESULTS

The results on the principal determinants for the syndrome, published in the reviewed articles, were chosen to propose reference values in the rat models of food induction.

CONCLUSION

The values obtained will serve as reference cut-of points in the development of the disease; in addition, the compilation of data will be useful in planning and executing research protocols in animal models.

Glycyrrhizin-induced changes in phospholipid dynamics studied by 1H NMR and MD simulation

Phospholipid bilayer constitutes the basis of the cell membrane. Any changes in its structure and dynamics could significantly affect the properties and functions of the cell membrane and associated proteins. It could, in its turn, affect the mechanism and strength of drug-membrane interaction. Phase transitions in lipid bilayer play an important role in cell life and in transmembrane transport of ions and drug molecules. In the present study we have tried to clarify the mechanism of glycyrrhizin bioactivity by the study of its influence on the lipid dynamics and phase transition of the lipid bilayer. For this purpose, a combination of nuclear magnetic resonance (NMR) and molecular dynamic (MD) simulations was used. Glycyrrhizin is the saponin extracted from licorice root. It displays a wide spectrum of biological activity and is frequently used in traditional medicine since ancient times. Now glycyrrhizin attracts additional attention as a novel multifunctional drug delivery system. We have established that glycyrrhizin interaction with dipalmitoylphosphatidylcholine lipid bilayers leads to changes in lipid mobility and phase transition temperature. NMR and MD results demonstrated that a glycyrrhizin molecule is able to integrate into a lipid bilayer and form stable aggregates inside. We hypothesize that surface curvatures caused by local changes in the lipid composition and the presence of phase boundaries might affect the permeability of the cell membrane.

Comprehensive RNA Sequencing in Adenoma-Cancer Transition Identified Predictive Biomarkers and Therapeutic Targets of Human CRC

Specific molecular biomarkers for predicting the transition from colorectal adenoma to cancer have been identified, however, circular RNA (circRNA)-related signatures remain to be clarified. We carried out high-throughput RNA sequencing to determine the expression profiles of circRNAs, microRNAs (miRNAs), and mRNAs in human colorectal cancer (CRC), adenoma, and adjacent normal tissues. We identified 84 circRNAs, 41 miRNAs, and 398 mRNAs that were commonly differentially expressed in CRC and adenoma tissues compared with normal tissues. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and protein-protein interaction (PPI) analyses identified numerous cancer-related hub genes that might serve as potential therapeutic targets in CRC. Competing endogenous RNA (ceRNA) networks, including three circRNAs, three miRNAs, and 28 mRNAs were constructed, suggesting their potential role in cancer progression. Representative differentially expressed RNAs were validated by the Cancer Genome Atlas (TCGA) database and real-time PCR experiments. Receiver operating characteristic (ROC) curve analysis identified three circRNAs (hsa_circ_0049487, hsa_circ_0066875, and hsa_circ_0007444) as possible novel biomarkers predicting the transition from colonic adenoma to cancer. Overall, our findings may provide novel perspectives to clarify the mechanisms of the transition from premalignant adenoma to cancer and identify specific circRNA-related signatures with possible applications for the early diagnosis of and as potential therapeutic targets in CRC.

Natural products in licorice for the therapy of liver diseases: Progress and future opportunities

Liver diseases related complications represent a significant source of morbidity and mortality worldwide, creating a substantial economic burden. Oxidative stress, excessive inflammation, and dysregulated energy metabolism significantly contributed to liver diseases. Therefore, discovery of novel therapeutic drugs for the treatment of liver diseases are urgently required. Licorice is one of the most commonly used herbal drugs in Traditional Chinese Medicine for the treatment of liver diseases and drug-induced liver injury (DILI). Various bioactive components have been isolated and identified from the licorice, including glycyrrhizin, glycyrrhetinic acid, liquiritigenin, Isoliquiritigenin, licochalcone A, and glycycoumarin. Emerging evidence suggested that these natural products relieved liver diseases and prevented DILI through multi-targeting therapeutic mechanisms, including anti-steatosis, anti-oxidative stress, anti-inflammation, immunoregulation, anti-fibrosis, anti-cancer, and drug-drug interactions. In the current review, we summarized the recent progress in the research of hepatoprotective and toxic effects of different licorice-derived bioactive ingredients and also highlighted the potency of these compounds as promising therapeutic options for the treatment of liver diseases and DILI. We also outlined the networks of underlying molecular signaling pathways. Further pharmacology and toxicology research will contribute to the development of natural products in licorice and their derivatives as medicines with alluring prospect in the clinical application.

The severity of rat liver injury by fructose and high fat depends on the degree of respiratory dysfunction and oxidative stress induced in mitochondria

BACKGROUND

High fat or fructose induces non-alcoholic fatty liver disease (NAFLD) accompanied of mitochondrial dysfunction and oxidative stress. Controversy remains about whether fructose or fat is more deleterious for NAFLD development. To get more insights about this issue and to determine if the severity of liver disease induced by fructose or fat is related to degree of mitochondrial dysfunction, we compared the effects of diets containing high fat (HF), fructose (Fr) or high fat plus fructose (HF + Fr) on NAFLD development, mitochondrial function, ROS production and lipid peroxidation.

METHODS

Wistar rats were assigned to four groups: Control, fed with standard rodent chow; High fat (HF), supplemented with lard and hydrogenated vegetable oil; Fructose (Fr), supplemented with 25% fructose in the drinking water; High fat plus fructose group (HF + Fr), fed with both HF and Fr diets. Rats were sacrificed after 6 weeks of diets consumption and the liver was excised for histopathological analysis by hematoxylin and eosin staining and for mitochondria isolation. Mitochondrial function was evaluated by measuring both mitochondrial respiration and complex I activity. Lipid peroxidation and ROS production were evaluated in mitochondria by the thiobarbituric acid method and with the fluorescent ROS probe 2,4-H₂DCFDA, respectively.

RESULTS

Fr group underwent the lower degree of both liver damage and mitochondrial dysfunction that manifested like less than 20% of hepatocytes with microvesicular steatosis and partial decrease in state 3 respiration, respectively. HF group displayed an intermediate degree of damage as it showed 40% of hepatocytes with microvesicular steatosis and diminution of both state 3 respiration and complex I activity. HF + Fr group displayed more severe damage as showed microvesicular steatosis in 60% of hepatocytes and inflammation, while mitochondria exhibited fully inhibited state 3 respiration, impaired complex I activity and increased ROS generation. Exacerbation of mitochondrial lipid peroxidation was observed in both the Fr and HF + Fr groups.

CONCLUSION

Severity of liver injury induced by fructose or fat was related to the degree of dysfunction and oxidative damage in mitochondria. Attention should be paid on the serious effects observed in the HF + Fr group as the typical Western diet is rich in both fat and carbohydrates.

Hispaglabridin B, a constituent of liquorice identified by a bioinformatics and machine learning approach, relieves protein-energy wasting by inhibiting forkhead box O1

BACKGROUND AND PURPOSE

Liquorice is the root of Glycyrrhiza glabra, which is a popular food in Europe and China that has previously shown benefits for skeletal fatigue and nutrient metabolism. However, the mechanism and active ingredients remain largely unclear. The aim of this study was to investigate the active ingredients of liquorice for muscle wasting and elucidate the underlying mechanisms.

EXPERIMENTAL APPROACH

RNA-Seq and bioinformatics analysis were applied to predict the main target of liquorice. A machine learning model and a docking tool were used to predict active ingredients. Isotope labelling experiments, immunostaining, Western blots, qRT-PCR, ChIP-PCR and luciferase reporters were utilized to test the pharmacological effects in vitro and in vivo. The reverse effects were verified through recombination-based overexpression.

KEY RESULTS

The liposoluble constituents of liquorice improved muscle wasting by inhibiting protein catabolism and fibre atrophy. We further identified FoxO1 as the target of liposoluble constituents of liquorice. In addition, hispaglabridin B (HB) was predicted as an inhibitor of FoxO1. Further studies determined that HB improved muscle wasting by inhibiting catabolism in vivo and in vitro. HB also markedly suppressed the transcriptional activity of FoxO1, with decreased expression of the muscle-specific E3 ubiquitin ligases MuRF1 and Atrogin-1.

CONCLUSIONS AND IMPLICATIONS

HB can serve as a novel natural food extract for preventing muscle wasting in chronic kidney disease and possibly other catabolic conditions.

Deep Ocean Minerals Minimize Eccentric Exercise-Induced Inflammatory Response of Rat Skeletal Muscle

Background: We have previously shown an accelerated recovery from muscle fatigue in men challenged by prolonged exercise after oral deep ocean minerals (DOM) supplementation. Here, we hypothesized a decrease in eccentric exercise-induced muscle inflammation in rats regularly consuming DOM-containing drinks (hardness 600 mg/L and fructose 11%).

Methods: Forty-seven male Sprague Dawley rats were randomized into 4 groups: Control (C, N = 12), Fructose (F, N = 12), Fructose+Exercise (FE, N = 12), and Fructose+Exercise+DOM (FED, N = 11). Since fructose is a commonly used ingredient in beverages, 11% of fructose was added as a vehicle of the study. Soleus muscles of rats were analyzed 24 h after an acute bout of downhill running following 9 weeks of DOM supplementation.

Results: Leukocyte infiltration and TNF-α mRNA of muscle in the FE group were 5 times and 4 times greater the F group, respectively, (P < 0.05). Both markers in the FED group were significantly lower than those in the FE group (P < 0.05). IL-10 mRNA of muscle in the F group was >eight fold greater than the C group (P < 0.05). The reduced glutathione (GSH) of muscle in the F group was 34% lower than that in the C group (P < 0.05). However, GSH levels were similar for the C and FED groups.

Conclusion: Prolonged fructose supplementation modulates inflammatory balance of rat skeletal muscle. The results of the study suggest that DOM can minimize eccentric exercise-induced inflammatory cytokine responses in rat skeletal muscle.

Glycyrrhizin ameliorates high fat diet-induced obesity in rats by activating NrF2 pathway

AIM

Obesity based on insulin resistance is a state of chronic oxidative stress and inflammation that are highly regulated through nuclear factor Erythroid 2-related factor 2 (NrF2) pathway.

MATERIALS AND METHODS

70 male Wistar rats were randomized into two models. The prophylactic model was 10weeks and rats were grouped into: normal group, GL group (received glycyrrhizin 50mg/kg/day orally along with normal pellet diet), HFD group and HFD+ GL group (received glycyrrhizin along with HFD). The treatment model was 14weeks and rats were grouped into: normal group, HFD group and HFD+GL group (received glycyrrhizin from the week 10).

KEY FINDINGS

Glycyrrhizin decreased significantly rat weights and insulin resistance, normalized lipid profile and reduced significantly the adipocytes size in adipose tissue and lipid deposition in the liver tissue through histopathologic examination. Furthermore, glycyrrhizin ameliorated obesity-induced oxidative stress which indicated by significant decrease in liver malondialdehyde level (P<0.001) and increase in the total antioxidant capacity (P<0.001). Interestingly, molecular mechanism of glycyrrhizin was explored, that included significant reduction of liver gluconeogenic enzymes mRNA expression (P<0.001), a significant increase of liver insulin receptor, NrF2 and homooxygenase-1 mRNA expressions (P<0.001) and significant increase and nuclear translocation of NrF2 in liver tissue.

SIGNIFICANCE

Glycyrrhizin ameliorates HFD-induced obesity in rats that may be attributed to its ability to increase insulin receptor expression and to activate NrF2 and subsequent homooxygenase-1 pathway. Thus, this work represents a safe natural compound (glycyrrhizin) that has a great role either as prophylaxis or treatment for insulin resistance related to obesity.

Toxicological Effects of Glycyrrhiza glabra (Licorice): A Review

Licorice (Glycyrrhiza glabra) has been considered as an herbal drug since ancient time. Nowadays, it is a well-known spice that possesses worth pharmacological effects. However, some relevant articles have revealed negative impacts of licorice in health. By considering the great wishes in using herbal medicine, it is important to show adverse effects of herbal medicine in health. At present, there are misunderstandings toward the safety of herbal medicines. Herein, we gathered scientific research projects on the toxicity effects of licorice and glycyrrhizin to highlight their safety. In this regards, we categorized our findings about the toxicity effects of licorice and glycyrrhizin in acute, sub-acute, sub-chronic, and chronic states. Besides, we discussed on the cytotoxicity, genotoxicity, mutagenicity, and carcinogenicity of licorice and glycyrrhizin as well as their developmental toxicity. This review disclosed that G. glabra and glycyrrhizin salts are moderately toxic. They need to be used with caution during pregnancy. G. glabra and glycyrrhizin possess selective cytotoxic effects on cancerous cells. The most important side effects of licorice and glycyrrhizin are hypertension and hypokalemic-induced secondary disorders. Licorice side effects are increased by hypokalemia, prolonged gastrointestinal transient time, decreased type 2 11-beta-hydroxysteroid dehydrogenase activities, hypertension, anorexia nervosa, old age, and female sex. Copyright © 2017 John Wiley & Sons, Ltd.

Review of Garcinia mangostana and its Xanthones in Metabolic Syndrome and Related Complications

Metabolic syndrome is coexistence of abdominal obesity, hyperglycemia, hyperlipidemia and hypertension that causes cardiovascular diseases, diabetes and their complications, low quality and short lifespan. Garcinia mangostana and its xanthones such as α-mangostin have been shown desirable effects such as anti-obesity, anti-hyperglycemic, anti-dyslipidemia, anti-diabetic and antiinflammatory effects in experimental studies. Various databases such as PubMed, Scopus and Web of Science with keywords of 'Garcinia mangostana', 'mangosteen', 'α-mangostin', 'metabolic syndrome', 'hypoglycemic', 'antihyperglicemic', 'antidiabetic', 'hypotensive', 'antihypertensive', 'atherosclerosis', 'arteriosclerosis' and 'hyperlipidemia' have been investigated in this search without publication time limitation. This study reviewed all pharmacological effects and molecular pathways of G. mangostana and its xanthones in the management of metabolic syndrome and its complications in in-vitro and in-vivo studies. Based on these studies, mangosteen and its xanthones have good potential to design human studies for controlling and modification of metabolic syndrome and its related disorders such as obesity, disrupted lipid profile, diabetes and its complications. Copyright © 2017 John Wiley & Sons, Ltd.

Applying a systems approach to thyroid physiology: Looking at the whole with a mitochondrial perspective instead of judging single TSH values or why we should know more about mitochondria to understand metabolism

Classical thinking in endocrine physiology squeezes our diagnostic handling into a simple negative feedback mechanism with a controller and a controlled variable. In the case of the thyroid this is reduced to TSH and fT3 and fT4, respectively. The setting of this tight notion has no free space for any additions. In this paper we want to challenge this model of limited application by proposing a construct based on a systems approach departing from two basic considerations. In first place since the majority of cases of thyroid disease develop and appear during life it has to be considered as an acquired condition. In the second place, our experience with the reversibility of morphological changes makes the autoimmune theory inconsistent.

While medical complexity can expand into the era of OMICS as well as into one where manipulations with the use of knock-outs and -ins are common in science, we have preferred to maintain a simple and practical approach. We will describe the interactions of iron, magnesium, zinc, selenium and coenzyme Q10 with the thyroid axis. The discourse will be then brought into the context of ovarian function, i.e. steroid hormone production. Finally the same elemental players will be presented in relation to the basic mitochondrial machinery that supports the endocrine.

We propose that an intact mitochondrial function can guard the normal endocrine function of both the thyroid as well as of the ovarian axis. The basic elements required for this function appear to be magnesium and iron. In the case of the thyroid, magnesium-ATP acts in iodine uptake and the heme protein peroxidase in thyroid hormone synthesis. A similar biochemical process is found in steroid synthesis with cholesterol uptake being the initial energy-dependent step and later the heme protein ferredoxin 1 which is required for steroid synthesis. Magnesium plays a central role in determining the clinical picture associated with thyroid disease and is also involved in maintaining fertility. With the aid of 3D sonography patients needing selenium and/or coenzyme Q10 can be easily identified. By this we firmly believe that physicians should know more about basic biochemistry and the way it fits into mitochondrial function in order to understand metabolism. Contemplating only TSH is highly reductionistic.

Outline

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Author's profiles and motivation for this analysis

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The philosophical alternatives in science and medicine

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Reductionism vs. systems approach in clinical thyroid disease guidelines

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The entry into complexity: the involvement of the musculoskeletal system

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Integrating East and West: teachings from Chinese Medicine and from evidence based medicine (EBM)

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Can a mathematical model represent complexity in the daily thyroid practice?

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How effective is thyroxine treatment?

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Resolving the situation of residual symptoms in treated patients with thyroid disease

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Importance of iron, zinc and magnesium in relation to thyroid function

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Putting together new concepts related to thyroid function for a systems approach

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Expanding our model into general aspects of medicine

Long-term soft drink and aspartame intake induces hepatic damage via dysregulation of adipocytokines and alteration of the lipid profile and antioxidant status

Dietary intake of fructose corn syrup in sweetened beverages is associated with the development of metabolic syndrome and obesity. We hypothesized that inflammatory cytokines play a role in lipid storage and induction of liver injury. Therefore, this study intended to explore the expression of adipocytokines and its link to hepatic damage. Rats were assigned to drink water, cola soft drink (free access) and aspartame (240 mg/kg body weight/day orally) for 2 months. The lipid profiles, liver antioxidants and pathology, and mRNA expression of adipogenic cytokines were evaluated. Subchronic intake of soft drink or aspartame substantially induced hyperglycemia and hypertriacylglycerolemia, as represented by increased serum glucose, triacylglycerol, low-density lipoprotein and very low-density lipoprotein cholesterol, with obvious visceral fatty deposition. These metabolic syndromes were associated with the up-regulation of leptin and down-regulation of adiponectin and peroxisome proliferator activated receptor-γ (PPAR-γ) expression. Moreover, alterations in serum transaminases accompanied by hepatic oxidative stress involving induction of malondialdehyde and reduction of superoxide dismutase, catalase, and glutathione peroxidase and glutathione levels are indicative of oxidative hepatic damage. Several cytoarchitecture alterations were detected in the liver, including degeneration, infiltration, necrosis, and fibrosis, predominantly with aspartame. These data suggest that long-term intake of soft drink or aspartame-induced hepatic damage may be mediated by the induction of hyperglycemia, lipid accumulation, and oxidative stress with the involvement of adipocytokines.