C-reactive protein impairs hepatic insulin sensitivity and insulin signaling in rats: role of mitogen-activated protein kinases

The comprehensive effects of high-sensitivity C-reactive protein and triglyceride glucose index on cardiometabolic multimorbidity

Background

The triglyceride-glucose index (TyG index) is one of the surrogate markers of insulin resistance, and high-sensitivity C-reactive protein (hsCRP) reflects systemic inflammation. Existing studies suggest that insulin resistance or systemic inflammation may be indicative of cardiometabolic disease, but few of the existing studies have combined the TyG index and inflammation levels before assessing cardiometabolic multimorbidity. Our study data came from the China Health and Retirement Longitudinal Study (CHARLS). Participants in this data were followed for 9 years, and we used these data to conduct a long-term analysis to assess the combined effects of the TyG index and hsCRP on cardiometabolic multimorbidity in Chinese adults over 45 years of age.

Purpose

To study the combined effect of TyG index and hsCRP on cardiometabolic multimorbidity in middle-aged as well as elderly Chinese.

Method

The study data came from the China Health and Retirement Longitudinal Study (CHARLS), which included a total of 4,483 middle-aged and elderly participants who did not have cardiovascular metabolic diseases at baseline, which was from CHARLS 2011, and the last survey was in 2020. A total of five cardiometabolic diseases were considered in this study: diabetes, hypertension, hyperlipidemia, heart disease and stroke. A person was defined as having cardiometabolic multimorbidity when he/she had two or more cardiometabolic diseases at the same time. TyG index (median as cut-off) and hsCRP (1mg/L as cut-off) were each divided into two groups and combined into four groups (Group L-L: TyG index=median & hsCRP<1mg/L; Group L-H: TyG index=1mg/L; Group H-H: TyG index>=median & hsCRP>=1mg/L). Multiple regression equations were fitted to analyse the combined influence of TyG index and hsCRP on cardiometabolic multimorbidity.

Results

TyG index increases the risk of CMM events independently of hsCRP, as does the reverse. When the TyG index is elevated and hsCRP is also elevated, this condition significantly increases the danger of cardiometabolic multimorbidity in middle-aged and elderly Chinese.

Conclusion

High levels of TyG index and hsCRP can enhance the danger of cardiometabolic multimorbidity in Chinese middle-aged and elderly people, and the joint use of hsCRP and TyG index assessment may be a better way to achieve primary prevention of cardiometabolic multimorbidity in Chinese middle-aged and elderly people.

Skatole Alleviates Osteoarthritis by Reprogramming Macrophage Polarization and Protecting Chondrocytes

Osteoarthritis (OA) is the most prevalent joint disease, yet effective disease-modifying OA drugs (DMOADs) remain elusive. Targeting macrophage polarization has emerged as a promising avenue for OA treatment. This study identified skatole through high-throughput screening as an efficient modulator of macrophage polarization. In vivo experiments demonstrated that skatole administration markedly reduced synovitis and cartilage damage in both destabilization of medial meniscus (DMM)-induced OA mice and monosodium iodoacetate (MIA)-induced OA rats. Mechanistically, skatole activated signal transducer and activator of transcription 6 (Stat6) signaling, promoting M2 macrophage polarization, while inhibiting nuclear factor-κB (NFκB) and mitogen-activated protein kinase (MAPK) signaling pathways to suppress M1 polarization. RNA-sequencing analysis, targeted metabolomics, and mitochondrial stress tests further revealed that skatole treatment shifted macrophages toward oxidative phosphorylation for energy production. Additionally, it up-regulated genes associated with glutathione metabolism and reactive oxygen species (ROS) pathways, reducing intracellular ROS production. The CUT&Tag assay results indicated that the downstream transcription factor p65 of NFκB can directly bind to gene loci related to inflammation, oxidative phosphorylation, and glutathione metabolism, thereby modulating gene expression. This regulatory process is inhibited by skatole. At the chondrocyte level, conditional medium from skatole-treated M1 macrophages balanced anabolism and catabolism in mouse chondrocytes and inhibited apoptosis. In IL1β-treated chondrocytes, skatole suppressed inflammation and catabolism without affecting apoptosis or anabolism. Overall, skatole maintains immune microenvironment homeostasis by modulating macrophage polarization in joints and preserves cartilage function by balancing chondrocyte anabolism and catabolism, effectively alleviating OA. These findings suggest skatole's potential as a DMOAD.

Potential Immunoregulatory Mechanism of Plant Saponins: A Review

Saponins are extracted from different parts of plants such as seeds, roots, stems, and leaves and have a variety of biological activities including immunomodulatory, anti-inflammatory effects, and hypoglycemic properties. They demonstrate inherent low immunogenicity and possess the capacity to effectively regulate both the innate and adaptive immune responses. Plant saponins can promote the growth and development of the body's immune organs through a variety of signaling pathways, regulate the activity of a variety of immune cells, and increase the secretion of immune-related cytokines and antigen-specific antibodies, thereby exerting the role of immune activity. However, the chemical structure of plant saponins determines its certain hemolytic and cytotoxicity. With the development of science and technology, these disadvantages can be avoided or reduced by certain technical means. In recent years, there has been a significant surge in interest surrounding the investigation of plant saponins as immunomodulators. Consequently, the objective of this review is to thoroughly examine the immunomodulatory properties of plant saponins and elucidate their potential mechanisms, with the intention of offering a valuable point of reference for subsequent research and advancement within this domain.

C-reactive protein during pregnancy and in the early postpartum predicts adverse metabolic health outcomes at 1 year postpartum in women with gestational diabetes

BACKGROUND

Women with gestational diabetes mellitus (GDM) have higher insulin resistance and/or reduced secretion, an increased risk of future diabetes and cardiovascular disease, which may be due to a pathological activation of the innate immune system. C-reactive protein (CRP) is induced by inflammatory cytokines and reflects innate immune activity. We investigated the prospective associations between CRP during the perinatal period with adverse metabolic outcomes at 1 year postpartum in women with previous GDM.

METHODS

We analyzed data from the MySweetheart trial that included 211 women with GDM at 28-32 weeks gestational age (GA). CRP was measured during  pregnancy at 28-32 weeks GA, at 6-8 weeks and at 1 year postpartum. Metabolic outcomes at 1 year postpartum included weight, total and central body fat, measures of insulin resistance and secretion and presence of the metabolic syndrome (MetS). A 75 g oral glucose tolerance test was performed to measure glucose and insulin values every 30 min over 2 h to calculate indices of insulin resistance (MATSUDA, HOMA-IR) and of absolute (AUCins/glu, HOMA-B) and insulin resistance-adjusted insulin secretion (ISSI-2).

RESULTS

CRP during pregnancy and at 6-8 weeks postpartum predicted increased weight, body fat and visceral adipose tissue (VAT), insulin resistance (higher HOMA-IR, lower MATSUDA), absolute insulin secretion (HOMA-B, AUCins/glu), a reduced adjusted insulin secretion (ISSI-2) and a higher prevalence of the MetS at 1 year postpartum (all p ≤ 0.036). These relationships particularly those concerning CRP during pregnancy, were independent of weight ( for VAT, insulin resistance and secretion indices, MetS; all p ≤ 0.032) and of body fat ( for VAT, MATSUDA, MetS; all p ≤ 0.038).  CONCLUSION: CRP during pregnancy and in the early postpartum predicted an adverse cardio-metabolic profile in women with prior GDM at 1 year postpartum independent of weight. The prospective association of CRP with increased insulin resistance and reduced adjusted insulin secretion hint to the role of inflammation in the development of impaired metabolism after GDM and could be used as an early marker for risk stratification.

Protective effects of Althaea officinalis L. extract against N-diethylnitrosamine-induced hepatocellular carcinoma in male Wistar rats through antioxidative, anti-inflammatory, mitochondrial apoptosis and PI3K/Akt/mTOR signaling pathways

Hepatocellular carcinoma is the fourth cause of death due to cancer and includes 90% of liver tumors. Therefore, in this study, it was tried to show that Althaea officinalis L. flower extract (ALOF) can protect hepatocytes against N-diethylnitrosamine (DEN)-induced hepatocellular carcinoma. Totally, 70 Wistar rats were divided into seven groups (n = 10/group) of sham, DEN, treatment with silymarin (SIL; DEN + SIL), treatment with ALOF (DEN + 250 and 500 ALOF), and cotreatment with SIL and ALOF (DEN + SIL + 250 and 500 ALOF). At the end of the study, the serum levels of liver indices (albumin, total protein, bilirubin, C-reactive protein, ALT, AST, and ALP), inflammatory cytokines (IL-6, IL-1β, IL-10, and TNF-α), and oxidants parameters (glutathione peroxidase [GPx], superoxide dismutase [SOD], catalase [CAT] activity along with nitric oxide [NO] levels) were evaluated. The level of Bax, Bcl-2, Caspase-3, p53, PI3K, mTOR, and AKT genes were measured. ALOF in cotreatment with SIL was able to regulate liver biochemical parameters, improve serum antioxidant indices, and decrease the level of proinflammatory cytokines significantly (p < .05). ALOF extract in both doses of 250 and 500 mg/kg in cotreatment with SIL caused a significant (p < .05) decrease in the p53-positive cells and a significant (p < .05) increase in Bcl-2-positive cells. Therefore, ALOF was able to modulate the proliferation of cancer cells and protect normal cells through the regulation of Bax/Bcl-2/p53 and PI3K/Akt/mTOR signaling pathways. It seems that ALOF can be used as a prodrug or complementary treatment in the protection of hepatocytes in induced damages caused by carcinogens.

The Association of Acute Phase Proteins in Stress and Inflammation-Induced T2D

Acute phase proteins (APPs), such as plasminogen activator inhibitor-1 (PAI-1), serum amyloid A (SAA), and C-reactive protein (CRP), are elevated in type-2 diabetes (T2D) and are routinely used as biomarkers for this disease. These APPs are regulated by the peripheral mediators of stress (i.e., endogenous glucocorticoids (GCs)) and inflammation (i.e., pro-inflammatory cytokines), with both implicated in the development of insulin resistance, the main risk factor for the development of T2D. In this review we propose that APPs, PAI-1, SAA, and CRP, could be the causative rather than only a correlative link between the physiological elements of risk (stress and inflammation) and the development of insulin resistance.

C-reactive protein perturbs alveolar bone homeostasis: an experimental study of periodontitis and diabetes in the rat

AIMS

To explore the role of C-reactive protein (CRP) in periodontitis and diabetes and its mechanism in alveolar bone homeostasis.

MATERIALS AND METHODS

In vivo, normal and Crp knockout rats were randomly divided into: control, diabetes, periodontitis, and diabetes and periodontitis (DP) groups respectively. The diabetes model was established using a high-fat diet combined with streptozotocin (STZ) injection. The periodontitis model was established by ligature combined with lipopolysaccharide injection. Alveolar bones were analyzed using microCT, histology, and immunohistochemistry. In vitro, human periodontal ligament cells (hPDLCs) were treated with lipopolysaccharide and high glucose. CRP knockdown lentivirus or CRP overexpression adenovirus combined with a PI3K/AKT signaling inhibitor or agonist were used to explore the regulatory mechanism of CRP in osteogenesis and osteoclastogenesis of hPDLCs, as evidenced by ALP staining, WB and qPCR.

RESULTS

In periodontitis and diabetes, CRP knockout decreased the alveolar bone loss and the expression levels of osteoclastogenic markers, while increasing the expression levels of osteogenic markers. CRP constrained osteogenesis while promoting the osteoclastogenesis of hPDLCs via PI3K/AKT signaling under high glucose and pro-inflammatory conditions.

CONCLUSIONS

CRP inhibits osteogenesis and promotes osteoclastogenesis via PI3K/AKT signaling under diabetic and pro-inflammatory conditions, thus perturbing alveolar bone homeostasis. This article is protected by copyright. All rights reserved.

Adipose tissue macrophage populations and inflammation are associated with systemic inflammation and insulin resistance in obesity

Obesity is accompanied by numerous systemic and tissue-specific derangements, including systemic inflammation, insulin resistance, and mitochondrial abnormalities in skeletal muscle. Despite growing recognition that adipose tissue dysfunction plays a role in obesity-related disorders, the relationship between adipose tissue inflammation and other pathological features of obesity is not well-understood. We assessed macrophage populations and measured the expression of inflammatory cytokines in abdominal adipose tissue biopsies in 39 nondiabetic adults across a range of body mass indexes (BMI 20.5-45.8 kg/m²). Skeletal muscle biopsies were used to evaluate mitochondrial respiratory capacity, ATP production capacity, coupling, and reactive oxygen species production. Insulin sensitivity (S_I) and β cell responsivity were determined from test meal postprandial glucose, insulin, c-peptide, and triglyceride kinetics. We examined the relationships between adipose tissue inflammatory markers, systemic inflammatory markers, S_I, and skeletal muscle mitochondrial physiology. BMI was associated with increased adipose tissue and systemic inflammation, reduced S_I, and reduced skeletal muscle mitochondrial oxidative capacity. Adipose-resident macrophage numbers were positively associated with circulating inflammatory markers, including tumor necrosis factor-α (TNFα) and C-reactive protein (CRP). Local adipose tissue inflammation and circulating concentrations of TNFα and CRP were negatively associated with S_I, and circulating concentrations of TNFα and CRP were also negatively associated with skeletal muscle oxidative capacity. These results demonstrate that obese humans exhibit increased adipose tissue inflammation concurrently with increased systemic inflammation, reduced insulin sensitivity, and reduced muscle oxidative capacity and suggest that adipose tissue and systemic inflammation may drive obesity-associated metabolic derangements.NEW AND NOTEWORTHY Adipose inflammation is proposed to be at the nexus of the systemic inflammation and metabolic derangements associated with obesity. The present study provides evidence to support adipose inflammation as a central feature of the pathophysiology of obesity. Adipose inflammation is associated with systemic and peripheral metabolic derangements, including increased systemic inflammation, reduced insulin sensitivity, and reduced skeletal muscle mitochondrial respiration.

Genetic ablation of C-reactive protein gene confers resistance to obesity and insulin resistance in rats

AIMS/HYPOTHESIS

Besides serving as a traditional inflammatory marker, C-reactive protein (CRP) is closely associated with the development of obesity, diabetes and cardiovascular diseases as a metabolic and inflammatory marker. We hypothesise that CRP protein directly participates in the regulation of energy and glucose metabolism rather than just being a surrogate marker, and that genetic deficiency of CRP will lead to resistance to obesity and insulin resistance.

METHODS

Crp gene deletion was achieved by transcription activator-like effector nuclease (TALEN) technology in rats. The Crp knockout animals were placed on either a standard chow diet or a high-fat diet. Phenotypic changes in body weight, glucose metabolism, insulin sensitivity, energy expenditure and inflammation condition were examined. The central impact of CRP deficiency on leptin and insulin hypothalamic signalling, as well as glucose homeostasis, were examined via intracerebral ventricular delivery of leptin and CRP plus glucose clamp studies in the wild-type and Crp knockout rats.

RESULTS

CRP deficiency led to a significant reduction in weight gain and food intake, elevated energy expenditure and improved insulin sensitivity after exposure to high-fat diet. Glucose clamp studies revealed enhanced hepatic insulin signalling and actions. Deficiency of CRP enhanced and prolonged the weight-reducing effect of central injected leptin and promoted the central and peripheral roles of leptin. By contrast, reinstatement of CRP into the hypothalamus of the knockout rats attenuated the effects of central leptin signalling on insulin sensitivity and peripheral glucose metabolism.

CONCLUSIONS/INTERPRETATION

This study represents the first line of genetic evidence that CRP is not merely a surrogate blood marker for inflammation and metabolic syndromes but directly regulates energy balance, body weight, insulin sensitivity and glucose homeostasis through direct regulation of leptin's central effect and hypothalamic signalling.

Transcriptome Analysis Reveals Possible Immunomodulatory Activity Mechanism of Chlorella sp. Exopolysaccharides on RAW264.7 Macrophages

In this study, the exopolysaccharides of Chlorella sp. (CEP) were isolated to obtain the purified fraction CEP4. Characterization results showed that CEP4 was a sulfated heteropolysaccharide. The main monosaccharide components of CEP4 are glucosamine hydrochloride (40.8%) and glucuronic acid (21.0%). The impact of CEP4 on the immune activity of RAW264.7 macrophage cytokines was detected, and the results showed that CEP4 induced the production of nitric oxide (NO), TNF-α, and IL-6 in a dose-dependent pattern within a range of 6 μg/mL. A total of 4824 differentially expressed genes (DEGs) were obtained from the results of RNA-seq. Gene enrichment analysis showed that immune-related genes such as NFKB1, IL-6, and IL-1β were significantly upregulated, while the genes RIPK1 and TLR4 were significantly downregulated. KEGG pathway enrichment analysis showed that DEGs were significantly enriched in immune-related biological processes, including toll-like receptor (TLR) signaling pathway, cytosolic DNA-sensing pathway, and C-type lectin receptor signaling pathway. Protein–protein interaction (PPI) network analysis showed that HSP90AB1, Rbx1, ISG15, Psmb6, Psmb3, Psmb8, PSMA7, Polr2f, Rpsa, and NEDD8 were the hub genes with an essential role in the immune activity of CEP4. The preliminary results of the present study revealed the potential mechanism of CEP4 in the immune regulation of RAW264.7 macrophages, suggesting that CEP4 is a promising immunoregulatory agent.

Hepatotoxicity induced by nanomaterials: mechanisms and in vitro models

The unique physicochemical properties of materials at nanoscale have opened a plethora of opportunities for applications in the pharmaceutical and medical field, but also in consumer products from food and cosmetics industries. As a consequence, daily human exposure to nanomaterials through distinct routes is considerable and, therefore, may raise health concerns. Many nanomaterials have been described to accumulate and induce adversity in the liver. Among these, silica and some types of metallic nanoparticles are the most broadly used in consumer products and, therefore, the most studied and reported. The reviewed literature was collected from PubMed.gov during the month of March 2020 using the search words "nanomaterials induced hepatotoxicity", which yielded 181 papers. This present paper reviews the hepatotoxic effects of nanomaterials described in in vitro and in vivo studies, with emphasis on the underlying mechanisms. The induction of oxidative stress and inflammation are the manifestations of toxicity most frequently reported following exposure of cells or animal models to different nanomaterials. Furthermore, the available in vitro models for the evaluation of the hepatotoxic effects of nanomaterials are discussed, highlighting the continuous interest in the development of more advanced and reliable in vitro models for nanotoxicology.

Common mechanisms for type 2 diabetes and psychosis: Findings from a prospective birth cohort

BACKGROUND

Psychosis and type 2 diabetes mellitus (T2DM) are commonly comorbid and may share pathophysiologic mechanisms. To investigate shared genetic variation and inflammation as potential common mechanisms, we tested: (i) associations between genetic predisposition for T2DM and psychotic experiences and psychotic disorder in young adults; (ii) the association between genetic predisposition for schizophrenia and insulin resistance (IR), a precursor of T2DM; and (iii) whether these associations are mediated by childhood inflammation.

METHODS

Psychotic experiences (PEs), psychotic disorder and IR were assessed at age 18. Polygenic risk scores (PRS) for T2DM and schizophrenia were derived based on large genome-wide association studies. Associations between PRS and psychotic/IR outcomes were assessed using regression analysis based on 3768 ALSPAC birth cohort participants with complete data. Inflammatory markers C-reactive protein (CRP) and interleukin 6 (IL-6) measured at age 9 were used in regression and mediation analyses.

RESULTS

Genetic predisposition for T2DM was associated with PEs (adjusted OR = 1.21; 95% CI, 1.01-1.45) and psychotic disorder (adjusted OR = 1.51; 95% CI, 1.04-2.03) at age 18 in a linear dose-response fashion. Genetic predisposition for schizophrenia was weakly associated with IR (adjusted OR = 1.10; 95% C·I, 0.99-1.22) at age 18. The association between genetic risk for T2DM and PEs was partly mediated by childhood CRP (p = .040).

CONCLUSIONS

Comorbidity between psychosis and T2DM may be partly underpinned by shared genes and inflammation. A summation of minor genetic variation representing lifetime risk for T2DM at conception may predispose individuals to psychosis in adulthood by influencing physiologic changes, such as low-grade inflammation, detectable as early as childhood.

Short-term, but not acute, intake of New Zealand blackcurrant extract improves insulin sensitivity and free-living postprandial glucose excursions in individuals with overweight or obesity

Abstract

Impaired postprandial glucose handling and low-grade systemic inflammation are risk factors for developing insulin resistance in individuals with overweight or obesity. Acute ingestion of anthocyanins improves postprandial glucose responses to a single carbohydrate-rich meal under strictly controlled conditions.

Purpose

Examine whether acute and short-term supplementation with anthocyanin-rich New Zealand blackcurrant (NZBC) extract can improve postprandial glucose responses to mixed-macronutrient meals.

Methods

Twenty-five overweight (BMI > 25 kg m²) sedentary individuals participated in one of the following double-blinded, randomised controlled trials: (1) ingestion of 600 mg NZBC extract or placebo prior to consumption of a high-carbohydrate, high-fat liquid meal (n = 12); (2) 8-days supplementation with NZBC extract (600 mg day⁻¹) or placebo, with insulin sensitivity and markers of inflammation assessed on day-7, and free-living postprandial glucose (continuous glucose monitoring) assessed on day-8 (n = 13).

Results

A single dose of NZBC extract had no effect on 3 h postprandial glucose, insulin or triglyceride responses. However, in response to short-term NZBC extract supplementation insulin sensitivity was improved (+ 22%; P = 0.011), circulating C-reactive protein concentrations decreased (P = 0.008), and free-living postprandial glucose responses to both breakfast and lunch meals were reduced (− 9% and − 8%, respectively; P < 0.05), compared to placebo.

Conclusion

These novel results indicate that repeated intake, rather than a single dose of NZBC extract, is required to induce beneficial effects on insulin sensitivity and postprandial glucose handling in individuals with overweight or obesity. Continuous glucose monitoring enabled an effect of NZBC extract to be observed under free-living conditions and highlights the potential of anthocyanin-rich supplements as a viable strategy to reduce insulin resistance.

Intra-individual association between C-reactive protein and insulin administration in postoperative lumbar spinal canal stenosis patients: A retrospective cohort study

The association of intra-individual variability in insulin requirements with C-reactive protein levels among acute phase patients remains unclear. This retrospective cohort study aimed to evaluate this association. Patients with type 2 diabetes undergoing surgery for lumbar spinal canal stenosis were included in the study. We analyzed 286 records of 49 patients using the linear mixed effects model. The model showed C-reactive protein levels to be significantly associated with insulin requirements, with an effect size of 0.60 U/day for an elevation of 1 mg/dL. The effect size was increased in patients with higher hemoglobin A1c levels. Our findings imply that C-reactive protein levels could be a useful clinical biomarker when blood glucose levels are controlled in acute phase patients.

Role of Heparin-Binding Epidermal Growth Factor-Like Growth Factor in Oxidative Stress-Associated Metabolic Diseases

Heparin-binding EGF-like growth factor (HB-EGF) is an EGF family member that interacts with epidermal growth factor receptor (EGFR) and ERBB4. Since HB-EGF was first identified as a novel growth factor secreted from a human macrophage cell line, numerous pathological and physiological functions related to cell proliferation, migration, and inflammation have been reported. Notably, the expression of HB-EGF is sensitively upregulated by oxidative stress in the endothelial cells and functions for auto- and paracrine-EGFR signaling. Overnutrition and obesity cause elevation of HB-EGF expression and EGFR signaling in the hepatic and vascular systems. Modulations of HB-EGF signaling showed a series of protections against phenotypes related to metabolic syndrome and advanced metabolic diseases, suggesting HB-EGF as a potential target against metabolic diseases.

HBOA ameliorates CCl4-incuded liver fibrosis through inhibiting TGF-β1/Smads, NF-κB and ERK signaling pathways

An ingredient was isolated from Acanthus ilicifolius and identified as 4-hydroxy-2(3H)-benzoxazolone (HBOA). Its protective effects and underlying mechanism on liver fibrosis were investigated. Briefly, rats were intragastrically administrated with 50% CCl₄ twice a week for 12 weeks to induce liver fibrosis. Meanwhile, the animals were treated with various medicines from weeks 8 to 12. Then the histological change, serum biochemical index, inflammatory factors and hepatocyte apoptosis were detected. Moreover, the TGF-β1/Smads, NF-κB and ERK signaling pathways were also detected to illustrate the underlying mechanism. The results showed that HBOA significantly ameliorated CCl₄-induced liver injury and collagen accumulation in rats, as evidenced by the histopathologic improvement. Moreover, HBOA markedly decreased hepatocyte apoptosis by regulating the expression levels of caspase-3, -9 and -12, as well as the Bcl-2 family. The mechanism study showed that HBOA significantly decreased the expressions of α-smooth muscle actin (α-SMA) and collagen and inhibited the generation of excessive extracellular matrix (ECM) components by restoring the balance between matrix metalloproteinases (MMPs) and its inhibitor (TIMPs). HBOA markedly alleviated oxidative stress and inflammatory cytokines through inhibiting the NF-κB pathway. In addition, HBOA significantly down-regulated the levels of TGF-β1, Smad2/3, Smad4 and up-regulated the level of Smad7, inhibiting the TGF-β1/Smads signaling pathway. Moreover, HBOA significantly blocked the ERK signaling pathway, leading to the inactivation of hepatic stellate cells. This study suggests that HBOA exerts a protective effect against liver fibrosis via modulating the TGF-β1/Smads, NF-κB and ERK signaling pathways, which will be developed as a potential agent for the treatment of liver fibrosis.

Tumor Progression Locus 2 in Hepatocytes Potentiates Both Liver and Systemic Metabolic Disorders in Mice

Tumor progression locus 2 (TPL2), a serine/threonine kinase, has been regarded as a potentially interesting target for the treatment of various diseases with an inflammatory component. However, the function of TPL2 in regulating hepatocyte metabolism and liver inflammation during the progression of nonalcoholic fatty liver disease (NAFLD) is poorly understood. Here, we report that TPL2 protein expression was significantly increased in fatty liver from diverse species, including humans, monkeys, and mice. Further investigations revealed that compared to wild-type (WT) littermates, hepatocyte-specific TPL2 knockout (HKO) mice exhibited improved lipid and glucose imbalance, reserved insulin sensitivity, and alleviated inflammation in response to high-fat diet (HFD) feeding. Overexpression of TPL2 in hepatocytes led to the opposite phenotype. Regarding the mechanism, we found that mitogen-activated protein kinase kinase 7 (MKK7) was the specific substrate of TPL2 for c-Jun N-terminal kinase (JNK) activation. TPL2-MKK7-JNK signaling in hepatocytes represents a promising drugable target for treating NAFLD and associated metabolic disorders. Conclusion: In hepatocytes, TPL2 acts as a key mediator that promotes both liver and systemic metabolic disturbances by specifically increasing MKK7-JNK activation.

QiDiTangShen Granules Reduced Diabetic Kidney Injury by Regulating the Phosphorylation Balance of the Tyrosine and Serine Residues of Insulin Receptor Substrate 1

Background

Diabetic nephropathy (DN) is a microvascular complication induced by diabetes mellitus (DM), which can affect life quality and long-term prognosis of patients with DM. Angiotensin-converting-enzyme inhibitors (ACEI)/angiotensin receptor blockers (ARB) are currently recommended for treating DN proteinuria, but patients receiving ACEI/ARB are at risk of elevated serum creatinine or potassium levels. Based on the “yin-yang” theory of traditional Chinese medicine, the present study explored the effect of QiDiTangShen (QDTS) granules on DN and the phosphorylation balance of tyrosine and serine residues of IRS-1.

Methods

In this experiment, db/db mice were used as an animal model for type 2 diabetic nephropathy. The intervention (QDTS granules and valsartan) started when the mice were 12 weeks old. C57BL/6 mice were used as normal control. The urine albumin excretion ratio (UAER) was measured by enzyme-linked immunosorbent assay (ELISA) before and after the intervention. The IRS-1, PI3K, Akt, and MAPK proteins expression and the phosphorylation levels were detected by western blot.

Results

QDTS granules reduced the 24-h urinary albumin excretion rate (UAE) in db/db mice with type 2 DM and attenuated the pathological changes of the kidney. QDTS granules also increased the activation level of the PI3K/Akt signaling pathway and reduced insulin resistance. In addition, QDTS granules inhibited the activation of ERK and p38MAPK and decreased the phosphorylation ratio of Ser307/Tyr896 of IRS-1 in renal tissue.

Conclusions

QDTS granules reduced DM-induced renal injury by improving insulin sensitivity via suppressing MAPK signaling and restoring the phosphorylation balance of tyrosine/serine of IRS-1.

Prophylactic administration of carnosine and melatonin abates the incidence of renal toxicity induced by an over dose of titanium dioxide nanoparticles

The alleviative effects of two antioxidants, carnosine (Car) and melatonin (Mel), against titanium dioxide nanoparticles (TiO₂ -NPs) toxicity-induced oxidative and inflammatory renal damage were examined in rats. Administration of these antioxidants along with TiO₂ -NPs effectively reduced serum urea, uric acid, creatinine, glucose, tumor necrosis factor-α, interleukin-6, C-reactive protein, immunoglobulin G, vascular endothelial growth factor, and nitric oxide, as well as a significant amelioration of the decrease in glutathione levels in renal tissue was observed, compared to those in rats treated with TiO₂ -NPs alone. The renoprotective properties of the antioxidants were confirmed by reduced intensity of renal damage as demonstrated by histological findings. In conclusion, Car and Mel play protective roles against TiO₂ -NPs-induced renal inflammation and oxidative injury, likely due to their antioxidant and anti-inflammatory properties.

Relationships of serum high-sensitivity C-reactive protein and body size with insulin resistance in a Japanese cohort

BACKGROUND

Impacts of chronic systemic inflammation and body size and their interaction effect on insulin resistance in Asian populations, in whom obesity is less common, are not fully understood. This study evaluated combined relationships of systemic inflammation and body size with insulin resistance in a Japanese cohort.

METHODS

We analyzed cross-sectional data from 1,074 eligible subjects (536 men and 538 women) aged 35-69 years who participated in the baseline survey of a cohort study in Tokushima Prefecture, Japan. Systemic inflammation level was assessed by serum high-sensitivity C-reactive protein (hs-CRP), and the degree of insulin resistance and beta-cell function were evaluated by the homeostasis model assessment insulin resistance (HOMA-IR) and beta-cell function (HOMA-β), respectively. Overweight and obesity were defined as a body mass index (BMI) of 23.0-24.9 kg/m2 and ≥25.0 kg/m2, respectively. Associations between serum hs-CRP (assessed as quartiles and additionally continuous values after log-transformation) and indices of glucose homeostasis were analysed adjusting for probable covariates, including BMI (quartiles). Combined associations of serum hs-CRP (≤median, >median) and body size (normal, overweight, obese) with insulin resistance as well as their interaction effect on insulin resistance were also evaluated.

RESULTS

Serum hs-CRP was dose-dependently associated with HOMA-IR, but not HOMA-β, after adjustment for probable covariates, including BMI. Subjects with obesity and elevated serum hs-CRP (>median) showed a high multivariable-adjusted HOMA-IR value of 1.32 (95% confidence interval (CI) 1.23, 1.41) compared with subjects with normal BMI and low serum hs-CRP (≤median) whose multivariable-adjusted HOMA-IR value was 1.14 (95% CI 1.06, 1.21). The interaction effect between body size (normal, overweight, obese) and serum hs-CRP (≤median, >median) on HOMA-IR was significant (P for interaction <0.001).

CONCLUSIONS

Our study suggests that elevated systemic inflammation is dose-dependently associated with increased insulin resistance, independent of the known risk factors, in a Japanese population. Concomitant obesity and elevated systemic inflammation may synergistically contribute to increased insulin resistance.

Protective Effects of Amarogentin against Carbon Tetrachloride-Induced Liver Fibrosis in Mice

Amarogentin, a secoiridoid glycoside that is mainly extracted from Swertia and Gentiana roots, has been suggested to exhibit many biological effects, including anti-oxidative, anti-tumour, and anti-diabetic activities. The present study was designed to evaluate the protective effects of amarogentin on carbon tetrachloride-induced liver fibrosis in vivo and the underlying mechanism. Fibrosis was induced by subcutaneous injections of 6 mL/kg of 20% carbon tetrachloride (dissolved in olive oil) twice per week for seven weeks. Mice were orally treated with 25, 50, and 100 mg/kg amarogentin and with colchicine as a positive control. Biochemical assays and histopathological investigations showed that amarogentin delayed the formation of liver fibrosis; decreased alanine aminotransferase, aspartate aminotransferase, malondialdehyde and hydroxyproline levels; and increased albumin, cyclic guanosine monophosphate, glutathione peroxidase, and superoxide dismutase levels. Moreover, amarogentin exhibited downregulation of α-smooth muscle actin and transforming growth factor-β₁ levels in immunohistochemical and Western blot analyses. The levels of phosphorylated extracellular regulated protein kinases, c-Jun N-terminal kinase, and p38 were also significantly reduced in all amarogentin-treated groups in a dose-dependent manner. These findings demonstrated that amarogentin exerted significant hepatoprotective effects against carbon tetrachloride-induced liver fibrosis in mice and suggested that the effect of amarogentin against liver fibrosis may be by anti-oxidative properties and suppressing the mitogen-activated protein kinase signalling pathway.

Systemic inflammation and family history in relation to the prevalence of type 2 diabetes based on an alternating decision tree

To investigate unknown patterns associated with type 2 diabetes in the Japanese population, we first used an alternating decision tree (ADTree) algorithm, a powerful classification algorithm from data mining, for the data from 1,102 subjects aged 35-69 years. On the basis of the investigated patterns, we then evaluated the associations of serum high-sensitivity C-reactive protein (hs-CRP) as a biomarker of systemic inflammation and family history of diabetes (negative, positive or unknown) with the prevalence of type 2 diabetes because their detailed associations have been scarcely reported. Elevated serum hs-CRP levels were proportionally associated with the increased prevalence of type 2 diabetes after adjusting for probable covariates, including body mass index and family history of diabetes (P for trend = 0.016). Stratified analyses revealed that elevated serum hs-CRP levels were proportionally associated with increased prevalence of diabetes in subjects without a family history of diabetes (P for trend = 0.020) but not in those with a family history or with an unknown family history of diabetes. Our study demonstrates that systemic inflammation was proportionally associated with increased prevalence of type 2 diabetes even after adjusting for body mass index, especially in subjects without a family history of diabetes.

Effect of vitamin K supplementation on insulin sensitivity: a meta-analysis

OBJECTIVE

To perform a systematic review and meta-analysis of randomized, placebo-controlled trials to assess the effect of vitamin K supplementation on insulin sensitivity.

DATA SOURCES

MEDLINE, the Cochrane Library, CINAHL, Web of Science, Scopus, clinicaltrials.gov, and clinicaltrialresults.org were searched up to January 2017. Reference lists of related papers were also scanned.

STUDY SELECTION

Randomized controlled trials were selected if they compared vitamin K supplementation with placebo or no treatment and reported homeostasis model assessment of insulin resistance, fasting plasma glucose, fasting plasma insulin, C-reactive protein, adiponectin, leptin, or interleukin-6 levels.

DATA EXTRACTION

Data extraction and study quality assessment were performed independently by two investigators using a standardized data extraction form. Any inconsistencies were resolved by a third reviewer. Effect estimates were pooled using inverse-variance weighted method. Heterogeneity was assessed by the I² and Q statistic.

RESULTS

A total of eight trials involving 1,077 participants met the inclusion criteria. A wide variety of participants were enrolled, including older men, postmenopausal women, prediabetic premenopausal women, and participants with a history of diabetes, hypertension, or vascular disease. Vitamin K1 and vitamin K2 (MK-4 and MK-7 subtypes) were assessed. Supplementation period ranged from 4 weeks to 3 years. Vitamin K supplementation did not affect insulin sensitivity as measured by homeostasis model assessment of insulin resistance, fasting plasma glucose, fasting plasma insulin, C-reactive protein, adiponectin, leptin, and interleukin-6 levels.

CONCLUSION

Our analysis suggests no effect of vitamin K supplementation on insulin sensitivity.

Decreased C-reactive protein induces abnormal vascular structure in a rat model of liver dysfunction induced by bile duct ligation

Background/Aims

Chronic liver disease leads to liver fibrosis, and although the liver does have a certain regenerative capacity, this disease is associated with dysfunction of the liver vessels. C-reactive protein (CRP) is produced in the liver and circulated from there for metabolism. CRP was recently shown to inhibit angiogenesis by inducing endothelial cell dysfunction. The objective of this study was to determine the effect of CRP levels on angiogenesis in a rat model of liver dysfunction induced by bile duct ligation (BDL).

Methods

The diameter of the hepatic vein was analyzed in rat liver tissues using hematoxylin and eosin (H&E) staining. The expression levels of angiogenic factors, albumin, and CRP were analyzed by real-time PCR and Western blotting. A tube formation assay was performed to confirm the effect of CRP on angiogenesis in human umbilical vein endothelial cells (HUVECs) treated with lithocholic acid (LCA) and siRNA-CRP.

Results

The diameter of the hepatic portal vein increased significantly with the progression of cirrhosis. The expression levels of angiogenic factors were increased in the cirrhotic liver. In contrast, the expression levels of albumin and CRP were significantly lower in the liver tissue obtained from the BDL rat model than in the normal liver. The CRP level was correlated with the expression of albumin in hepatocytes treated with LCA and siRNA-CRP. Tube formation was significantly decreased in HUVECs when they were treated with LCA or a combination of LCA and siRNA-CRP.

Conclusion

CRP seems to be involved in the abnormal formation of vessels in hepatic disease, and so it could be a useful diagnostic marker for hepatic disease.

Medium-chain triglyceride ameliorates insulin resistance and inflammation in high fat diet-induced obese mice

PURPOSE

The aim of the present study was to investigate the in vivo effects of dietary medium-chain triglyceride (MCT) on inflammation and insulin resistance as well as the underlying potential molecular mechanisms in high fat diet-induced obese mice.

METHODS

Male C57BL/6J mice (n = 24) were fed one of the following three diets for a period of 12 weeks: (1) a modified AIN-76 diet with 5 % corn oil (normal diet); (2) a high-fat control diet (17 % w/w lard and 3 % w/w corn oil, HFC); (3) an isocaloric high-fat diet supplemented with MCT (17 % w/w MCT and 3 % w/w corn oil, HF-MCT). Glucose metabolism was evaluated by fasting blood glucose levels and intraperitoneal glucose tolerance test. Insulin sensitivity was evaluated by fasting serum insulin levels and the index of homeostasis model assessment-insulin resistance. The levels of serum interleukin-6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor-α were measured by ELISA, and hepatic activation of nuclear factor κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways was determined using western blot analysis.

RESULTS

Compared to HFC diet, consumption of HF-MCT did not induce body weight gain and white adipose tissue accumulation in mice. HFC-induced increases in serum fasting glucose and insulin levels as well as glucose intolerance were prevented by HF-MCT diet. Meanwhile, HF-MCT resulted in significantly lower serum IL-6 level and higher IL-10 level, and lower expression levels of inducible nitric oxide synthase and cyclooxygenase-2 protein in liver tissues when compared to HFC. In addition, HF-MCT attenuated HFC-triggered hepatic activation of NF-κB and p38 MAPK.

CONCLUSIONS

Our study demonstrated that MCT was efficacious in suppressing body fat accumulation, insulin resistance, inflammatory response, and NF-κB and p38 MAPK activation in high fat diet-fed mice. These data suggest that MCT may exert beneficial effects against high fat diet-induced insulin resistance and inflammation.

Effect of omega-3 on hepatic regeneration in adult living donors undergoing hepatic resections for liver transplantation: A randomized controlled trial

BACKGROUND

Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) have been shown to improve liver regeneration in experimental models. Aim was to evaluate the effects of ω-3 PUFAs on hepatic regeneration in adult living donors undergoing partial hepatectomy for liver transplantation (LDLT).

METHODS

Forty LDLT donors were categorized into 2 groups: received either intravenous ω-3 PUFA-enriched lipid emulsion 20% infusion 7 mL/kg once a day for 2 days before surgery and postoperative day (POD) 0 (S group) or glucose 5% (C group). Hepatic regeneration was assessed by volume of the liver after 1 month using computed tomography, and serial serum levels of hepatocyte growth factor were measured at POD 1, 3, and 5.

RESULTS

Liver volume after 1 month was significantly larger in the S group than the C group (1286.75 ± 122.781 cm(3) vs 1169.15 ± 128.3, respectively; P = .00). Both the regeneration index and the regeneration percentage were significantly higher in the S group than the C group (P = .02 and P = .00, respectively). Serum levels of hepatocyte growth factor were significantly higher in the S group on POD 1, 3, and 5 than the C group ([in pg/mL] 188.10 ± 74.25 vs 123.30 ± 13.56, P = .00; 127.55 ± 32.40 vs 109.25 ± 8.89, P = .02; and 109.45 ± 21.44 vs 96.70 ± 5.57, P = .01; respectively).

CONCLUSION

Omega-3 polyunsaturated fatty acids effectively promoted liver regeneration and functional recovery following portal hypertension in the setting of LDLT.

Longitudinal association of C-reactive protein and Haemoglobin A1c over 13 years: the European Prospective Investigation into Cancer--Norfolk study

Background

Type-2 diabetes is associated with systemic inflammation and higher C-reactive protein (CRP) levels. However, the longitudinal association of CRP and haemoglobin-A_1c (HbA_1c) has not been described in large prospective studies. Understanding such associations may shed light on the role of inflammation in development of type-2 diabetes and its complications such as cardiovascular diseases.

Methods

EPIC-Norfolk is a cohort study of men and women aged 40–79 years at time of recruitment (1993–1997). Serum CRP (mg/l) was measured using a high-sensitivity assay at baseline and 13-years follow-up. HbA_1c (%) was measured at baseline, 4, and 13 years. Participants were excluded if they were diagnosed with diabetes or were taking diabetes medication. Data on at least one measurement of CRP and HbA_1c was available for 14228 participants (55 % of the cohort).

Results

In the cross-sectional analysis of baseline data, a 1-SD higher log_e-CRP (about three-fold higher CRP) was associated with 0.06 (95 % CI 0.04, 0.08) higher HbA_1c (%) adjusted for potential confounders. In longitudinal analysis using multivariable linear mixed models, change in CRP over 13 years was to a similar extent positively associated with increase in HbA_1c, such that 1-SD higher longitudinal change in log_e-CRP was associated with 0.04 (95 % CI 0.02, 0.05) increase in HbA_1c.

Conclusion

In this study we found longitudinal observational evidence suggesting that increase in systemic inflammation is associated with an increase in HbA_1c and thus systemic inflammation may have a role in development of type-2 diabetes and its complications.

Potent effects of dioscin against liver fibrosis

We previously reported the promising effects of dioscin against liver injury, but its effect on liver fibrosis remains unknown. The present work investigated the activities of dioscin against liver fibrosis and the underlying molecular mechanisms. Dioscin effectively inhibited the cell viabilities of HSC-T6, LX-2 and primary rat hepatic stellate cells (HSCs), but not hepatocytes. Furthermore, dioscin markedly increased peroxisome proliferator activated receptor-γ (PPAR-γ) expression and significantly reduced a-smooth muscle actin (α-SMA), transforming growth factor-β1 (TGF-β1), collagen α1 (I) (COL1A1) and collagen α1 (III) (COL3A1) levels in vitro. Notably, dioscin inhibited HSCs activation and induced apoptosis in activated HSCs. In vivo, dioscin significantly improved body weight and hydroxylproline, laminin, α-SMA, TGF-β1, COL1A1 and COL3A1 levels, which were confirmed by histopathological assays. Dioscin facilitated matrix degradation, and exhibited hepatoprotective effects through the attenuation of oxidative stress and inflammation, in addition to exerting anti-fibrotic effects through the modulation of the TGF-β1/Smad, Wnt/β-catenin, mitogen-activated protein kinase (MAPK) and mitochondrial signaling pathways, which triggered the senescence of activated HSCs. In conclusion, dioscin exhibited potent effects against liver fibrosis through the modulation of multiple targets and signaling pathways and should be developed as a novel candidate for the treatment of liver fibrosis in the future.

Elevated muscle TLR4 expression and metabolic endotoxemia in human aging

Aging is associated with alterations in glucose metabolism and sarcopenia that jointly contribute to a higher risk of developing type 2 diabetes. Because aging is considered as a state of low-grade inflammation, in this study we examined whether older, healthy (lean, community-dwelling) participants have altered signaling flux through toll-like receptor 4 (TLR4), a key mediator of innate and adaptive immune responses. We also examined whether a 4-month aerobic exercise program would have an anti-inflammatory effect by reducing TLR4 expression and signaling. At baseline, muscle TLR4, nuclear factor κB p50 and nuclear factor κB p65 protein content, and c-Jun N-terminal kinase phosphorylation were significantly elevated in older versus young participants. The plasma concentration of the TLR4 agonist lipopolysaccharide and its binding protein also were significantly elevated in older participants, indicative of metabolic endotoxemia, which is a recently described phenomenon of increased plasma endotoxin level in metabolic disease. These alterations in older participants were accompanied by decreased insulin sensitivity, quadriceps muscle volume, and muscle strength. The exercise training program increased insulin sensitivity, without affecting quadriceps muscle volume or strength. Muscle TLR4, nuclear factor κB, and c-Jun N-terminal kinase, and plasma lipopolysaccharide and lipopolysaccharide binding protein were not changed by exercise. In conclusion, insulin resistance and sarcopenia of aging are associated with increased TLR4 expression/signaling, which may be secondary to metabolic endotoxemia.

Stressful life events are associated with insulin resistance among Chinese immigrant women in the United States

BACKGROUND

Chinese immigrants experience increased chronic disease risk following migration to the US. Although the impact of lifestyle changes (e.g., diet) on disease risk has been extensively studied, associations of psychosocial stress and disease risk have attracted less attention. Thus, the objective of the present study was to examine associations between stress and insulin resistance in foreign-born Chinese American women.

METHODS

From October, 2005 to April, 2008, 423 women recruited from southeastern Pennsylvania completed questionnaires reporting stressful life events. Blood samples were analyzed for fasting insulin and fasting glucose levels, which were used to estimate insulin resistance according to the homeostasis model assessment (HOMA_IR).

RESULTS

In logistic regression analyses, a greater number of negative life events was associated with insulin resistance (OR=1.17, 95% CI=1.02-1.34), controlling for age, level of acculturation, marital status, body mass index, and waist circumference. Similarly, greater negative life event impact ratings were also associated with insulin resistance (OR=1.08, 95% CI=1.01-1.16) controlling for relevant covariates.

CONCLUSIONS

This is one of the first studies to examine associations between psychosocial stress and insulin resistance in Chinese immigrant women. These findings contribute to a growing body of literature on stress and diabetes risk in an immigrant population.

Energy metabolism in the liver

The liver is an essential metabolic organ, and its metabolic function is controlled by insulin and other metabolic hormones. Glucose is converted into pyruvate through glycolysis in the cytoplasm, and pyruvate is subsequently oxidized in the mitochondria to generate ATP through the TCA cycle and oxidative phosphorylation. In the fed state, glycolytic products are used to synthesize fatty acids through de novo lipogenesis. Long-chain fatty acids are incorporated into triacylglycerol, phospholipids, and/or cholesterol esters in hepatocytes. These complex lipids are stored in lipid droplets and membrane structures, or secreted into the circulation as very low-density lipoprotein particles. In the fasted state, the liver secretes glucose through both glycogenolysis and gluconeogenesis. During pronged fasting, hepatic gluconeogenesis is the primary source for endogenous glucose production. Fasting also promotes lipolysis in adipose tissue, resulting in release of nonesterified fatty acids which are converted into ketone bodies in hepatic mitochondria though β-oxidation and ketogenesis. Ketone bodies provide a metabolic fuel for extrahepatic tissues. Liver energy metabolism is tightly regulated by neuronal and hormonal signals. The sympathetic system stimulates, whereas the parasympathetic system suppresses, hepatic gluconeogenesis. Insulin stimulates glycolysis and lipogenesis but suppresses gluconeogenesis, and glucagon counteracts insulin action. Numerous transcription factors and coactivators, including CREB, FOXO1, ChREBP, SREBP, PGC-1α, and CRTC2, control the expression of the enzymes which catalyze key steps of metabolic pathways, thus controlling liver energy metabolism. Aberrant energy metabolism in the liver promotes insulin resistance, diabetes, and nonalcoholic fatty liver diseases.

A blueberry-enriched diet improves renal function and reduces oxidative stress in metabolic syndrome animals: potential mechanism of TLR4-MAPK signaling pathway

Background

Metabolic syndrome (MetS) is characterized by a cluster of health factors that indicate a higher risk for cardio-renal diseases. Recent evidence indicates that antioxidants from berries are alternative to attenuate oxidative stress and inflammation. We tested the hypothesis that inflammation-induced renal damage is triggered by the activation of TLR4, and subsequent modulation of redox-sensitive molecules and mitogen-activated protein kinase (MAPK) pathway.

Methods

Five-week old lean and obese Zucker rats (LZR and OZR) were fed a blueberry-enriched diet or an isocaloric control diet for 15 weeks. A glucose tolerance test and acute renal clearance experiments were performed. Gene and protein expression levels for TLR4, cytokines and phosphorylation of ERK and p38MAPK were measured. Kidney redox status and urinary albumin levels were quantified. Renal pathology was evaluated histologically.

Results

Control OZR exhibited lower glucose tolerance; exacerbated renal function parameters; increased oxidative stress. Gene and protein expression levels of TLR4 were higher and this was accompanied by increased renal pathology with extensive albuminuria and deterioration in antioxidant levels in OZR. In addition, OZR had increased phosphorylation of ERK and p38MAPK. Blueberry-fed OZR exhibited significant improvements in all these parameters compared to OZR.

Conclusion

TLR4-MAPK signaling pathway is a key to the renal structural injury and dysfunction in MetS and blueberry (BB) protect against this damage by inhibiting TLR4.

Significance

This is the first study to put forth a potential mechanism of TLR4-induced kidney damage in a model of MetS and to elucidate a downstream mechanism by which blueberry exert their reno-protective effects.

Potential impact of quercetin and idebenone against immuno- inflammatory and oxidative renal damage induced in rats by titanium dioxide nanoparticles toxicity

The aim of this study was to investigate the toxic impacts of titanium dioxide nanoparticles (TiO₂-NPs) on rat kidneys and the possible prophylactic role of either quercetin or idebenone. TiO₂-NPs were administered orally at either 600 mg or 1 g/kg body weight for 5 consecutive days to evaluate dose-dependent toxicity referred to the OECD guidelines for testing of chemicals. The results showed that administration of either low or high repeated doses of TiO₂-NPs to rats significantly increases serum kideney function biomarkers (urea, creatinine and uric acid) as well as increases in serum glucose and serum immuno- inflammatory biomarkers including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), immunoglobin g (IGg), vascular endothelial growth factor (VEGF, angiogenic factor) and nitric oxide (NO) with a concomitant decrease in renal GSH content versus normal control values. The increase in these biomarkers was more evident in rats intoxicated with high TiO₂-NPs repeated doses. Oral co- administration of either quercetin or idebenone (each 200mg/Kg body weight) daily for three weeks to rats intoxicated by either of the two doses markedly ameliorated TiO₂-NPs induced alteration in the above biomarkers. The prophylactic impacts of both agents on biochemical markers were more pronounced in rats received low TiO₂-NPs repeated doses. The biochemical investigation was supported by histological examination. In conclusion, The data showed the severity in renotoxicity of TiO₂-NPs was dose-dependent and the protective effect of quercetin and idebenone may be related to their antioxidant and anti-inflammatory properties.

An Intimate Relationship between ROS and Insulin Signalling: Implications for Antioxidant Treatment of Fatty Liver Disease

Oxidative stress damages multiple cellular components including DNA, lipids, and proteins and has been linked to pathological alterations in nonalcoholic fatty liver disease (NAFLD). Reactive oxygen species (ROS) emission, resulting from nutrient overload and mitochondrial dysfunction, is thought to be a principal mediator in NAFLD progression, particularly toward the development of hepatic insulin resistance. In the context of insulin signalling, ROS has a dual role, as both a facilitator and inhibitor of the insulin signalling cascade. ROS mediate these effects through redox modifications of cysteine residues affecting phosphatase enzyme activity, stress-sensitive kinases, and metabolic sensors. This review highlights the intricate relationship between redox-sensitive proteins and insulin signalling in the context of fatty liver disease, and to a larger extent, the importance of reactive oxygen species as primary signalling molecules in metabolically active cells.

Serial changes of serum growth factor levels and liver regeneration after partial hepatectomy in healthy humans

This study aimed to investigate the associations of the serial changes of serum levels of various growth factors with liver regeneration after hepatectomy in healthy liver donors. Sixteen healthy liver donors who underwent conventional liver resection were included. Serum levels of various growth factors before hepatectomy and on postoperative day (POD) 1, 3, 5 and 7 were measured. Liver volume data calculated by multi-detector computed tomography using workstation. The ratio of remnant liver volume on POD 0 to liver volume before the operation was 51% ± 20%. The ratio of liver volume on POD 14 to liver volume on POD 0 were inversely correlated with remnant liver volume on POD 0 (r = −0.91). The ratio of liver volume on POD 14 to liver volume on POD 0 were significantly correlated with serum hepatocyte growth factor (HGF) levels on POD 1 (r = 0.54), serum leptin levels on POD 1 (r = 0.54), and serum macrophage colony-stimulating factor (M-CSF) levels on POD 5 (r = 0.76) and POD 7 (r = 0.80). These results suggest that early-phase elevation of serum levels of HGF, leptin and M-CSF may be associated with the acceleration of liver regeneration after hepatectomy in humans.

Astragaloside IV suppresses collagen production of activated hepatic stellate cells via oxidative stress-mediated p38 MAPK pathway

Oxidative stress is involved in hepatic fibrogenesis. Activation of hepatic stellate cells (HSCs), the key effectors in hepatic fibrogenesis, is characterized by overproduction of extracellular matrix. Astragaloside IV, the active component of Radix Astragali, has antioxidant properties and antifibrotic potential in renal fibrosis. Little is known about the role of astragaloside IV in liver and its involvement in hepatic fibrosis. This study aims at evaluating the antifibrotic potential of astragaloside IV and characterizing involved signal transduction pathways in culture-activated HSCs. Our results show that astragaloside IV attenuates oxidative stress in culture-activated HSCs, as demonstrated by scavenging reactive oxygen species and reducing lipid peroxidation, and elevates the level of cellular glutathione by stimulating Nrf2gene expression. Depletion of cellular glutathione by buthionine sulfoximine or abrogation of p38 MAPK by SB-203580 evidently eliminates the inhibitory effects of astragaloside IV on genes relevant to HSC activation. These results demonstrate that astragaloside IV inhibits HSC activation by inhibiting generation of oxidative stress and associated p38 MAPK activation and provide novel insights into the mechanisms of astragaloside IV as an antifibrogenic candidate in the prevention and treatment of liver fibrosis.

Diabetes and nonalcoholic Fatty liver disease: a pathogenic duo

Recent data increasingly support a complex interplay between the metabolic condition diabetes mellitus and the pathologically defined nonalcoholic fatty liver disease (NAFLD). NAFLD predicts the development of type 2 diabetes and vice versa, and each condition may serve as a progression factor for the other. Although the association of diabetes and NAFLD is likely to be partly the result of a "common soil," it is also probable that diabetes interacts with NAFLD through specific pathogenic mechanisms. In particular, through interrelated metabolic pathways currently only partly understood, diabetes appears to accelerate the progression of NAFLD to nonalcoholic steatohepatitis, defined by the presence of necroinflammation, with varying degrees of liver fibrosis. In the research setting, obstacles that have made the identification of clinically significant NAFLD, and particularly nonalcoholic steatohepatitis, difficult are being addressed with the use of new imaging techniques combined with risk algorithms derived from peripheral blood profiling. These techniques are likely to be used in the diabetes population in the near future. This review examines the pathogenic links between NAFLD and diabetes by exploring the epidemiological evidence in humans and also through newer animal models. Emerging technology to help screen noninvasively for differing pathological forms of NAFLD and the potential role of preventive and therapeutic approaches for NAFLD in the setting of diabetes are also examined.

The Wnt signaling pathway effector TCF7L2 is upregulated by insulin and represses hepatic gluconeogenesis

Certain single nucleotide polymorphisms (SNPs) in transcription factor 7-like 2 (TCF7L2) are strongly associated with the risk of type 2 diabetes. TCF7L2 and β-catenin (β-cat) form the bipartite transcription factor cat/TCF in stimulating Wnt target gene expression. cat/TCF may also mediate the effect of other signaling cascades, including that of cAMP and insulin in cell-type specific manners. As carriers of TCF7L2 type 2 diabetes risk SNPs demonstrated increased hepatic glucose production, we aimed to determine whether TCF7L2 expression is regulated by nutrient availability and whether TCF7L2 and Wnt regulate hepatic gluconeogenesis. We examined hepatic Wnt activity in the TOPGAL transgenic mouse, assessed hepatic TCF7L2 expression in mice upon feeding, determined the effect of insulin on TCF7L2 expression and β-cat Ser⁶⁷⁵ phosphorylation, and investigated the effect of Wnt activation and TCF7L2 knockdown on gluconeogenic gene expression and glucose production in hepatocytes. Wnt activity was observed in pericentral hepatocytes in the TOPGAL mouse, whereas TCF7L2 expression was detected in human and mouse hepatocytes. Insulin and feeding stimulated hepatic TCF7L2 expression in vitro and in vivo, respectively. In addition, insulin activated β-cat Ser⁶⁷⁵ phosphorylation. Wnt activation by intraperitoneal lithium injection repressed hepatic gluconeogenic gene expression in vivo, whereas lithium or Wnt-3a reduced gluconeogenic gene expression and glucose production in hepatic cells in vitro. Small interfering RNA-mediated TCF7L2 knockdown increased glucose production and gluconeogenic gene expression in cultured hepatocytes. These observations suggest that Wnt signaling and TCF7L2 are negative regulators of hepatic gluconeogenesis, and TCF7L2 is among the downstream effectors of insulin in hepatocytes.

Significance of decoy receptor 3 (Dcr3) and external-signal regulated kinase 1/2 (Erk1/2) in gastric cancer

Background

Decoy receptor 3 (DcR3), a member of the tumor necrosis factor receptor (TNFR) superfamily, is associated with anti-tumor immunity suppression. It is highly expressed in many tumors, and its expression can be regulated by the MAPK/MEK/ERK signaling pathway. The MAPK/MEK/ERK pathway has been reported to be a regulator in tumor occurrence, development and clonal expansion. External-signal regulated kinase (ERK) is a vital member of this pathway.

Results

The expression of DcR3 and ERK1/2 in tumor tissues of gastric cancer patients was significantly higher than the non-cancerous group (P < 0.05). There was no statistical difference among tumor tissues from patients with different ages or gender, and even of different differentiation (P > 0.05). However, in patients with stage I gastric cancer, the DcR3 and ERK1/2 levels were significantly lower than patients with more advanced stages.

Conclusions

DcR3 and ERK1/2 play a vital role in the development of gastric cancer, and they may be new markers for indicating the efficiency of gastric cancer treatment in the future.

Metabolic nuclear receptor signaling and the inflammatory acute phase response

The acute phase response (APR) classically refers to the rapid reprogramming of gene expression and metabolism in response to inflammatory cytokine signaling. As components of the innate immune system, hepatocyte-derived acute phase proteins (APPs) play a central role in restoring tissue homeostasis. Recently, an intriguing 'metaflammatory' facet of the APR became evident with chronically elevated APP levels being connected to metabolic syndrome disorders. The causality of these connections is unclear but could relate to adverse metabolic and inflammatory disturbances, particularly those affecting lipoprotein properties, cholesterol metabolism and atherogenesis. Here we review these aspects with an emphasis on the emerging importance of lipid-sensing nuclear receptors (LXRs, LRH-1, PPARs), in conjunction with anti-inflammatory transrepression pathways, as physiological and pharmacological relevant modulators of the APR.