Role of peroxisome proliferators-activated receptors in the pathogenesis and treatment of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease （NAFLD） is highly prevalent and can result in nonalcoholic steatohepatitis （NASH） and progressive liver disease including cirrhosis and hepatocellular carcinoma. A growing body of literature implicates the peroxisome proliferators- activated receptors （PPARs） in the pathogenesis and treatment of NAFLD. These nuclear hormone receptors impact on hepatic triglyceride accumulation and insulin resistance. The aim of this review is to describe the data linking PPARα and PPART to NAFLD/NASH and to discuss the use of PPAR ligands for the treatment of NASH.

Peroxisome proliferator-activated receptor agonists:A new hope towards the management of alcoholic liver disease

In this editorial,we examine a paper by Koizumi et al,on the role of peroxisome proliferator-activated receptor(PPAR)agonists in alcoholic liver disease(ALD).The study determined whether elafibranor protected the intestinal barrier and reduced liver fibrosis in a mouse model of ALD.The study also underlines the role of PPARs in intestinal barrier function and lipid homeostasis,which are both affected by ALD.Effective therapies are necessary for ALD because it is a critical health issue that affects people worldwide.This editorial analyzes the possibility of PPAR agonists as treatments for ALD.As key factors of inflammation and metabolism,PPARs offer multiple methods for managing the complex etiology of ALD.We assess the abilities of PPARα,PPARγ,and PPARβ/δagonists to prevent steatosis,inflammation,and fibrosis due to liver diseases.Recent research carried out in preclinical and clinical settings has shown that PPAR agonists can reduce the severity of liver disease.This editorial discusses the data analyzed and the obstacles,advantages,and mechanisms of action of PPAR agonists for ALD.Further research is needed to understand the efficacy,safety,and mechanisms of PPAR agonists for treating ALD.

Peroxisome proliferator-activated receptors as targets to treat metabolic diseases:Focus on the adipose tissue,liver,and pancreas

The world is experiencing reflections of the intersection of two pandemics:Obesity and coronavirus disease 2019.The prevalence of obesity has tripled since 1975 worldwide,representing substantial public health costs due to its comorbidities.The adipose tissue is the initial site of obesity impairments.During excessive energy intake,it undergoes hyperplasia and hypertrophy until overt inflammation and insulin resistance turn adipocytes into dysfunctional cells that send lipotoxic signals to other organs.The pancreas is one of the organs most affected by obesity.Once lipotoxicity becomes chronic,there is an increase in insulin secretion by pancreatic beta cells,a surrogate for type 2 diabetes mellitus(T2DM).These alterations threaten the survival of the pancreatic islets,which tend to become dysfunctional,reaching exhaustion in the long term.As for the liver,lipotoxicity favors lipogenesis and impairs beta-oxidation,resulting in hepatic steatosis.This silent disease affects around 30%of the worldwide population and can evolve into end-stage liver disease.Although therapy for hepatic steatosis remains to be defined,peroxisome proliferator-activated receptors(PPARs)activation copes with T2DM management.Peroxisome PPARs are transcription factors found at the intersection of several metabolic pathways,leading to insulin resistance relief,improved thermogenesis,and expressive hepatic steatosis mitigation by increasing mitochondrial beta-oxidation.This review aimed to update the potential of PPAR agonists as targets to treat metabolic diseases,focusing on adipose tissue plasticity and hepatic and pancreatic remodeling.

Role of adipokines and peroxisome proliferator-activated receptors in nonalcoholic fatty liver disease

Intrahepatic fat deposition has been demonstrated in patients with nonalcoholic fatty liver disease(NAFLD). Genetic and environmental factors are important for the development of NAFLD. Diseases such as obesity, diabetes, and hypertension have been found to be closely associated with the incidence of NAFLD. Evi-dence suggests that obesity and insulin resistance are the major factors that contribute to the development of NAFLD. In comparing the factors that contribute to the buildup of excess calories in obesity, an imbalance of energy homeostasis can be considered as the basis. Among the peripheral signals that are generated to regulate the uptake of food, signals from adipose tissue are of major relevance and involve the maintenance of energy homeostasis through processes such as lipo-genesis, lipolysis, and oxidation of fatty acids. Advances in research on adipose tissue suggest an integral role played by adipokines in NAFLD. Cytokines secreted by adipocytes, such as tumor necrosis factor-α, transform-ing growth factor-β, and interleukin-6, are implicated in NAFLD. Other adipokines, such as leptin and adiponectin and, to a lesser extent, resistin and retinol binding protein-4 are also involved. Leptin and adiponectin can augment the oxidation of fatty acid in liver by activating the nuclear receptor super-family of transcription fac-tors, namely peroxisome proliferator-activated receptor(PPAR)-α. Recent studies have proposed downregula-tion of PPAR-α in cases of hepatic steatosis. This re-view discusses the role of adipokines and PPARs with regard to hepatic energy metabolism and progression of NAFLD.

Peroxisome proliferator-activated receptors as targets to treat non-alcoholic fatty liver disease

Lately, the world has faced tremendous progress in the understanding of non-alcoholic fatty liver disease(NAFLD) pathogenesis due to rising obesity rates. Peroxisome proliferator-activated receptors(PPARs) are transcription factors that modulate the expression of genes involved in lipid metabolism, energy homeostasis and inflammation, being altered in diet-induced obesity. Experimental evidences show that PPAR-alpha is the master regulator of hepatic beta-oxidation(mitochondrial and peroxisomal)and microsomal omega-oxidation, being markedly decreased by high-fat(HF) intake. PPAR-beta/delta is crucial to the regulation of forkhead box-containing protein O subfamily-1 expression and, hence, the modulation of enzymes that trigger hepatic gluconeogenesis. In addition, PPAR-beta/delta can activate hepatic stellate cells aiming to the hepatic recovery from chronic insult. On the contrary, PPAR-gamma upregulation by HF diets maximizes NAFLD through the induction of lipogenic factors, which are implicated in the fatty acid synthesis. Excessive dietary sugars also upregulate PPAR-gamma, triggering de novo lipogenesis and the consequent lipid droplets deposition within hepatocytes. Targeting PPARs to treat NAFLD seems a fruitful approach as PPAR-alpha agonist elicits expressive decrease in hepatic steatosis by increasing mitochondrial beta-oxidation, besides reduced lipogenesis. PPAR-beta/delta ameliorates hepatic insulin resistance by decreasing hepatic gluconeogenesis at postprandial stage. Total PPAR-gamma activation can exert noxious effects by stimulating hepatic lipogenesis. However, partial PPAR-gamma activation leads to benefits, mainly mediated by increased adiponectin expression and decreased insulin resistance. Further studies are necessary aiming at translational approaches useful to treat NAFLD in humans worldwide by targeting PPARs.

Peroxisome proliferator-activated receptors for hypertension

Peroxisome proliferator-activated receptors(PPARs) are ligand-activated transcription factors belonging to the nuclear receptor superfamily, which is composed of four members encoded by distinct genes(α, β, γ, and δ). The genes undergo transactivation or transrepression under specific mechanisms that lead to the induction or repression of target gene expression. As is the case with other nuclear receptors, all four PPAR isoforms contain five or six structural regions in four functional domains; namely, A/B, C, D, and E/F. PPARs have many functions, particularly functions involving control of vascular tone, inflammation, and energy homeostasis, and are, therefore, important targets for hypertension, obesity, obesity-induced inflammation, and metabolic syndrome in general. Hence, PPARs also represent drug targets, and PPARα and PPARγ agonists are used clinically in the treatment of dyslipidemia and type 2 diabetes mellitus, respectively. Because of their pleiotropic effects, they have been identified as active in a number of diseases and are targets for the development of a broad range of therapies for a variety of diseases. It is likely that the range of PPARγ agonist therapeutic actions will result in novel approaches to lifestyle and other diseases. The combination of PPARs with reagents or with other cardiovascular drugs, such as diuretics and angiotensin Ⅱ receptor blockers, should be studied.This article provides a review of PPAR isoform characteristics, a discussion of progress in our understanding of the biological actions of PPARs, and a summary of PPAR agonist development for patient management. We also include a summary of the experimental and clinical evidence obtained from animal studies and clinical trials conducted to evaluate the usefulness and effectiveness of PPAR agonists in the treatment of lifestyle-related diseases.

THE INCREASE IN PLASMINOGEN ACTIVATOR INHIBITOR TYPE-1 EXPRESSION BY STIMULATION OF ACTIVATORS FOR PEROXISOME PROLIFERATOR-ACTIVATED RECEPTORS IN HUMAN ENDOTHELIAL CELLS

Objective.To investigate the effect of peroxis ome proliferator-activated recept ors(PPARs )activators on plasminogen activator inhibitor ty pe-1(PAI-1)expression in human umbilical vein e ndothelial cells and the possi-ble mechanism.Methods.Human umbilical vein endothelial ce lls(HUVECs )were obtained from normal fetus,and cul-tured conventionally.Then the HUVECs were exposed to test agents(linolenic acid,linoleic acid,oleic acid,stearic acid and prostaglandin J 2 respectively)in varying concentrations with fresh media.RT -PCR and ELISA were applied to determine the expression of PPARs and PAI-1in HUVECs.Results.PPARα,PPARδand PPARγmRNA were detected by using RT-PCR in HUVECs.Treatment of HUVECs with PPARαand PPARγactivators---linolenic acid,linoleic acid,oleic acid and prostaglandin J 2 respectively,but not with stearic a cid could augment PAI-I mRNA expression and protein secretion in a concentration-dependent manner.However,the mRNA expressions of 3subclasses of PPAR with their activators in HUVECs were not changed compared w ith controls.Conclusion.HUVECs express PPARs.PPARs activators may increase PAI-1expression in ECs,but the underlying mechanism remains uncle ar.Although PPARs expression was not enhanced after stimulated by their activators in ECs,the role of functionally active PPARs in regulating PA I-1expression in ECs needs to be further investigated by using transient gen e transfection assay.

An innovative approach for the treatment of Alzheimer's disease: the role of peroxisome proliferator-activated receptors and their ligands in development of alternative therapeutic interventions

Alzheimer＇s disease is a multifactorial pathology, for which no cure is currently available. Nowadays, researchers are moving towards a new hypothesis of the onset of the illness, linking it to a metabolic impairment, q-his innovative approach will lead to the identification of new targets for the preparation of new effective drugs. Peroxisome proliferator-activated receptors and their ligands are the ideal candidates to reach the necessary breakthrough to defeat this complicate disease.

Role of peroxisome proliferator-activated receptors alpha and gamma in gastric ulcer: An overview of experimental evidences

Peroxisome proliferator-activated receptors(PPARs) are ligand-activated transcription factors belonging to the nuclear hormone receptor superfamily. Three subtypes, PPARα, PPARβ/δ, and PPARγ, have been identifiedso far. PPARα is expressed in the liver, kidney, small intestine, heart, and muscle, where it activates the fatty acid catabolism and control lipoprotein assembly in response to long-chain unsaturated fatty acids, eicosanoids, and hypolipidemic drugs(e.g., fenofibrate). PPARβ/δ is more broadly expressed and is implicated in fatty acid oxidation, keratinocyte differentiation, wound healing, and macrophage response to very low density lipoprotein metabolism. This isoform has been implicated in transcriptional-repression functions and has been shown to repress the activity of PPARα or PPARγ target genes. PPARγ1 and γ2 are generated from a single-gene peroxisome proliferator-activated receptors gamma by differential promoter usage and alternative splicing. PPARγ1 is expressed in colon, immune system(e.g., monocytes and macrophages), and other tissues where it participates in the modulation of inflammation, cell proliferation, and differentiation. PPARs regulate gene expression through distinct mechanisms: Liganddependent transactivation, ligand-independent repression, and ligand-dependent transrepression. Studies in animals have demonstrated the gastric antisecretory activity of PPARα agonists like ciprofibrate, bezafibrate and clofibrate. Study by Pathak et al also demonstrated the effect of PPARα agonist, bezafibrate, on gastric secretion and gastric cytoprotection in various gastric ulcer models in rats. The majority of the experimental studies is on pioglitazone and rosiglitazone, which are PPARγ activators. In all the studies, both the PPARγ activators showed protection against the gastric ulcer and also accelerate the ulcer healing in gastric ulcer model in rats. Therefore, PPARα and PPARγ may be a target for gastric ulcer therapy. Finally, more studies are also needed to confirm the involvement of PPARs α and γ in gastric ulcer.

Peroxisome proliferator-activated receptor γ and colorectal cancer

Peroxisome proliferator-activated receptors(PPARs) are members of the nuclear hormone receptor superfamily and ligand-activated transcription factors.PPARγ plays an important role in adipocyte differentiation,lipid storage and energy dissipation in adipose tissue,and is involved in the control of inflammatory reactions as well as in glucose metabolism through the improvement of insulin sensitivity.Growing evidence has demonstrated that activation of PPARγ has an antineoplastic effect in tumors,including colorectal cancer.High expression of PPARγ is detected in human colon cancer cell lines and adenocarcinoma.This review describes the molecular mechanisms by which PPARγ regulates tumorigenesis in colorectal cancer,and examines current clinical trials evaluating PPARγ agonists as therapeutic agents for colorectal cancer.

EFFECT OF PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR ACTIVATORS ON TUMOR NECROSIS FACTOR-αEXPRESSION IN NEONATAL RAT CARDIAC MYOCYTES

Objective To investigate the effect of peroxisome proliferator-activated receptor-α(PPARα) and PPARγactivators on tumor necrosis factor-α(TNFα) expression in neonatal rat cardiac myocytes. Methods Primary cultures of cardiac myocytes from 1- to 3-day-old Wistar rats were prepared, and myocytes were ex-posed to lipopolysaccharide (LPS) and varying concentrations of PPARαor PPARγactivator (fenofibrate or pioglitazone).RT-PCR and ELISA were used to measure TNFα, PPARα, and PPARγexpression in cultured cardiac myocytes. Transient tr-ansfection of TNFαpromoter with or without nuclear factor-kappaB (NF-κB) binding site to cardiac myocytes was performed. Results Pretreatment of cardiac myocytes with fenofibrate or pioglitazone inhibited LPS-induced TNFαmRNA and protein expression in a dose-dependent manner. However, no significant changes were observed on PPARαor PPARγmRNA expression when cardiac myocytes were pretreated with fenofibrate or pioglitazone. Proportional suppression of TNFαpromoter activity was observed when myocytes was transiently transfected with whole length of TNFαpromoter (-721/+17) after being stimulated with LPS and fenofibrate or pioglitazone, whereas no change of promoter activity was observed with transfection of TNFαreporter construct in deletion of NF-κB binding site (-182/+17). Conclusions PPARαand PPARγactivators may inhibit cardiac TNFαexpression but not accompanied by change of PPARαor PPARγmRNA expression. Therefore PPARαand PPARγactivators appear to play a role in anti-inflammation. The mechanism may partly be involved in suppression of the NF-κB pathway.

Data-driven analysis of chemicals,proteins and pathways associated with peanut allergy:from molecular networking to biological interpretation

Peanut allergy is majorly related to severe food induced allergic reactions.Several food including cow's milk,hen's eggs,soy,wheat,peanuts,tree nuts(walnuts,hazelnuts,almonds,cashews,pecans and pistachios),fish and shellfish are responsible for more than 90%of food allergies.Here,we provide promising insights using a large-scale data-driven analysis,comparing the mechanistic feature and biological relevance of different ingredients presents in peanuts,tree nuts(walnuts,almonds,cashews,pecans and pistachios)and soybean.Additionally,we have analysed the chemical compositions of peanuts in different processed form raw,boiled and dry-roasted.Using the data-driven approach we are able to generate new hypotheses to explain why nuclear receptors like the peroxisome proliferator-activated receptors(PPARs)and its isoform and their interaction with dietary lipids may have significant effect on allergic response.The results obtained from this study will direct future experimeantal and clinical studies to understand the role of dietary lipids and PPARisoforms to exert pro-inflammatory or anti-inflammatory functions on cells of the innate immunity and influence antigen presentation to the cells of the adaptive immunity.

Nuclear receptors and pathogenesis of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with a median overall survival time of 5 mo and the five years survival less than 5%, a rate essentially unchanged over the course of the years. A well defined progression model of accumulation of genetic alterations ranging from single point mutations to gross chromosomal abnormalities has been introduced to describe the origin of this disease. However, due to the its subtle nature and concurring events PDAC cure remains elusive. Nuclear receptors (NR) are members of a large superfamily of evolutionarily conserved ligand-regulated DNA-binding transcription factors functionally involved in important cellular functions ranging from regulation of metabolism, to growth and development. Given the nature of their ligands, NR are very tempting drug targets and their pharmacological modulation has been widely exploited for the treatment of metabolic and inflammatory diseases. There are now clear evidences that both classical ligand-activated and orphan NR are involved in the pathogenesis of PDAC from its very early stages; nonetheless many aspects of their role are not fully understood. The purpose of this review is to highlight the striking connections that link peroxisome proliferator activated receptors, retinoic acid receptors, retinoid X receptor, androgen receptor, estrogen receptors and the orphan NR Nur, chicken ovalbumin upstream promoter transcription factor II and the liver receptor homologue-1 receptor to PDAC development, connections that could lead to the identification of novel therapies for this disease.

Role of nuclear receptors in breast cancer stem cells

The recapitulation of primary tumour heterogenity and the existence of a minor sub-population of cancer cells,capable of initiating tumour growth in xenografts on serial passages, led to the hypothesis that cancer stem cells(CSCs) exist. CSCs are present in many tumours, among which is breast cancer. Breast CSCs(BCSCs) are likely to sustain the growth of the primary tumour mass, as wellas to be responsible for disease relapse and metastatic spreading. Consequently, BCSCs represent the most significant target for new drugs in breast cancer therapy. Both the hypoxic condition in BCSCs biology and proinflammatory cytokine network has gained increasing importance in the recent past. Breast stromal cells are crucial components of the tumours milieu and are a major source of inflammatory mediators. Recently, the antiinflammatory role of some nuclear receptors ligands has emerged in several diseases, including breast cancer. Therefore, the use of nuclear receptors ligands may be a valid strategy to inhibit BCSCs viability and consequently breast cancer growth and disease relapse.

Inhibition of proliferation and transforming growth factor β3 protein expression by peroxisome proliferators-activated receptor γ ligands in human uterine leiomyoma cells

Background Rosiglitazone is known as the most potent and specific peroxisome proliferators-activated receptor γ （PPAR-γ） ligand. It has potentially far-reaching effects on pathophysiological processes, from cancer to atherosclerosis and diabetes. However, it is not clear whether rosiglitazone affects the protein expression of transforming growth factor β3 （TGF-β3） and the cell proliferation in human uterine leiomyoma cells in vitro.Methods Human uterine leiomyoma tissues were dissected and cultured. Cells were divided into 5 groups： one control group and other four groups with different concentrations of rosiglitazone （10^-7, 10^-8, 10^-9 and 10^-10 mol/L）. Cells were cultured for 72 hours in serum-free Dulbecco＇s modified Eagle＇s medium. MTT reduction assay was used to detect the cell proliferation. Reverse transcription polymerase chain reaction （RT-PCR） was used to detect the mRNA expression of PPAR-γ and TGF-β3. Immunofluorescence staining was used to detect the expressions of PPAR-γ and TGF-β3 proteins. Results MTT reduction assay indicated that the treatment with rosiglitazone （from 10^-7 to 10^-9 mol/L） resulted in an inhibition of the cell growths after 72 hours （P〈0.01）. RT-PCR analysis revealed that 10^-7 mol/L rosiglitazone significantly affected the gene expression at 72-hour： PPAR-γ mRNA expression was up-regulated and TGF-β3 mRNA was down-regulated and rosiglitazone at the concentration of 10-7 mol/L affected these most effectively （P〈0.01）. Immunofluorescence staining demonstrated that treatment with 10^-7 mol/L rosiglitazone resulted in the significant changes of PPAR-γ and TGF-β3 protein expressions compared with the other treatment groups and the control group at 72-hour （P〈0.01）. All the effects of rosiglitazone on uterine leiomyoma cells were dose- and time-dependent in vitro. Conclusions The present study demonstrates that the PPAR-γ activator, rosiglitazone, inhibits the cell proliferation partly through the regulations of PPAR-γ and TGF-β3 expressions. The cross-talk between the signal pathways of PPAR-γ and TGF-β3 may be involved in the process.

Inflammatory reaction versus endogenous peroxisome proliferator- activated receptors expression, re-exploring secondary organ complications of spontaneously hypertensive rats

Background The chronic pathological changes in vascular walls of hypertension may exert destructive effects on multiple organ systems. Accumulating evidence indicates that inflammatory reactions are involved in the pathological changes of hypertension. Three peroxisome proliferator-activated receptors （PPARs） have been identified： PPARa, PPARβ/δ, and PPARγ, all of which have multiple biological effects, especially the inhibition of inflammation. The aim of this study was to evaluate PPAR isoforms expression profile in important organs of spontaneously hypertensive rats （SHR） and to understand the modulation of endogenous PPAR isoforms under inflammatory condition. Methods l]ssues （kidney, liver, heart, and brain） were dissected from SHR and age-matched control Wistar-Kyoto rats （WKY） to investigate the abundance of PPAR isoforms and PPAR-responsive genes （acyI-CoA oxidase and CD36）. The expression of CCAAT/enhancer-binding protein 6 （C/EBP6）, which can trans-activate PPARγ expression, was also observed. The inflammatory response was analyzed by the expression of inflammatory mediators inducible nitric oxide synthase （iNOS）, intercellular adhesion molecule-1 （ICAM-1）, vascular cell adhesion molecule-1 （VCAM-1）, E-selectin, interleukin-1 beta （IL-1β）, and tumor necrosis factor alpha （TNFα）, and formation of carbonyl and nitrated proteins. Results The expressions of 3 PPAR isoforms and PPAR-responsive genes were markedly upregulated in SHR compared with those of WKY. Specifically, the expression of PPARa protein in the kidney, liver, heart and brain increased by 130.76 %, 91.48%, 306.24%, and 90.70%; PPARβ/δ upregulated by 109.34%, 161.98%, 137.04%, and 131.66%; PPARγ increased by 393.76%, 193.17%, 559.29%, and 591.18%. In consistent with the changes in PPARy, the expression of C/EBPδ was also dramatically elevated in SHR. Inflammatory mediators expressions were significantly increased in the most organs of SHR than WKY. As a consequence, increased formation of carbonyl and nitrated proteins were also observed in the most organs of SHR. Conclusions These findings suggest an enhanced inflammatory response in the organs of SHR, which might play a key role in pathogenesis of hypertension and secondary organ complications. Changes （increases） in PPARs expression may reflect a compensatory mechanism to the inflammatory status of hypertensive rats.

静宁鸡PPARα基因克隆与生物信息学分析

为阐明静宁鸡PPARα基因的结构及功能,根据NCBI上登录的原鸡PPARα基因的CDS序列设计引物,以静宁鸡肾脏为材料采用PCR的方法,对目的基因进行克隆,并测序。根据测序的结果,采用各类分析软件,对所获得的DNA片段进行生物信息学分析。结果成功克隆了静宁鸡PPARα基因的全长CDS序列。生物信息学分析结果表明,该基因CDS全长1 407 bp,所编码的蛋白质包含468个氨基酸。其分子量为52 300,等电点为5.85。在二级和三级结构上,α-螺旋和无规则卷曲为蛋白的主要结构形式。PPARα蛋白是一个亲水性蛋白质,不存在跨膜区域,不含信号肽,没有N-糖基化位点,但存在16个O-糖基化位点,存在25个丝氨酸(Ser)磷酸化位点、12个苏氨酸(Thr)磷酸化位点和6个酪氨酸(Tyr)磷酸化位点。静宁鸡PPARα蛋白在第100～168个氨基酸之间有1个ZnF_C4结构域,在第264～449个氨基酸之间有1个HOLI结构域。同源性分析结果表明,静宁鸡PPARα基因与原鸡的亲缘关系最近。静宁鸡PPARα基因的成功克隆和功能预测为进一步研究PPARα基因在静宁鸡脂肪代谢中的作用提供了基础。

Rosiglitazone prevents murine hepatic fibrosis induced by Schistosoma japonicum

AIM: To evaluate the effect of rosiglitazone in a murine model of liver fibrosis induced by Schistosoma japonicum infection. METHODS: A total of 50 mice were randomly and averagely divided into groups A, B, C, D and E. The mice in group A served as normal controls, while those in the other four groups were infected with Schistosoma japonicum to induce the model of liver fibrosis. Besides, the mice in groups C, D and E were treated with praziquantel, rosiglitazone and praziquantel plus rosiglitazone, respectively. NF-κB binding activity and expression of PPARγ-mRNA were determined by Western blot assay and real-time quantitative PCR. Radioimmunonassay technique was used to detect the serum content changes of TNF-α and IL-6. Histological specimens were stained with HE. Expression of TGF-β1, a-smooth muscle actin and type ?Ⅰ?and type Ⅲ collagen was detected by immunohistochemistry and multimedia color pathographic analysis system. RESULTS: Inflammation and fibrosis in the rosiglitazone plus praziquantel treatment group (group E) were lightest among the mice infected with Schistosoma (P < 0.05). To further explore the mechanism of rosiglitazone action, we found that rosiglitazone can significantly increase the expression of PPARγ [E: -18.212 ± (-3.909) vs B: -27.315 ± (-6.348) and C: -25.647 ± (-5.694), P < 0.05],reduce the NF-κB binding activity (E: 88.89 ± 19.34 vs B: 141.11 ± 15.37, C: 112.89 ± 20.17 and D: 108.89 ± 20.47, P < 0.05), and lower the serum level of TNF-α (E: 1.613 ± 0.420 ng/mL vs B: 2.892 ± 0.587 ng/mL, C: 2.346 ± 0.371 ng/mL and D: 2.160 ± 0.395 ng/mL, P < 0.05) and IL-6 (E: 0.106 ± 0.021 ng/mL vs B: 0.140 ± 0.031 ng/mL and C: 0.137 ± 0.027 ng/mL, P < 0.05) in mice with liver fibrosis. Rosiglitazone can also substantially reduce the hepatic expression of TGF-β1, α-SMA type Ⅰand type Ⅲ collagen in mice with liver fibrosis. CONCLUSION: The activation of PPARγ by its ligand can retard liver fibrosis and suggest the use of rosiglitazone for the treatment of liver fibrosis due to Schistosoma japonicum infection.

Current role of fenofibrate in the prevention and management of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease(NAFLD) is a common health problem with a high mortality burden due to its liver- and vascular-specific complications. It is associated with obesity, high-fat diet as well as with type 2 diabetes mellitus(T2DM) and metabolic syndrome(MetS).Impaired hepatic fatty acid(FA) turnover together with insulin resistance are key players in NAFLD pathogenesis. Peroxisome proliferator-activated receptors(PPARs)are involved in lipid and glucose metabolic pathways.The novel concept is that the activation of the PPARαsubunit may protect from liver steatosis. Fenofibrate, by activating PPARα, effectively improves the atherogenic lipid profile associated with T2DM and MetS. Experimental evidence suggested various protective effects of the drug against liver steatosis. Namely, fenofibraterelated PPARα activation may enhance the expression of genes promoting hepatic FA β-oxidation. Furthermore, fenofibrate reduces hepatic insulin resistance. It also inhibits the expression of inflammatory mediators involved in non-alcoholic steatohepatitis pathogenesis.These include tumor necrosis factor-α, intercellular cell adhesion molecule-1, vascular cell adhesion molecule-1and monocyte chemoattractant protein-1. Consequently, fenofibrate can limit hepatic macrophage infiltration. Other liver-protective effects include decreased oxidative stress and improved liver microvasculature function. Experimental studies showed that fenofibrate can limit liver steatosis associated with high-fat diet,T2DM and obesity-related insulin resistance. Few studies showed that these benefits are also relevant even in the clinical setting. However, these have certain limitations. Namely, these were uncontrolled, their sample size was small, fenofibrate was used as a part of multifactorial approach, while histological data were absent.In this context, there is a need for large prospective studies, including proper control groups and full assessment of liver histology.

A clinical trial of combined use of rosiglitazone and 5-aminosalicylate for ulcerative colitis

AIM: To investigate the therapeutic effects of the combined use of rosiglitazone and aminosalicylate on mild or moderately active ulcerative colitis (UC).METHODS: According to the national guideline for diagnosis and treatment of inflammatory bowel disease (IBD) in China, patients with mild or moderately active UC in our hospital were selected from July to November, 2004. Patients with infectious colitis, amoebiasis, or cardiac, renal or hepatic failure and those who had received corticosteroid or immunosuppressant treatment within the last month were excluded. Following a quasi-randomization principle, patients were allocated alternatively into the treatment group (TG) with rosiglitazone 4 mg/d plus 5-ASA 2 g/d daily or the control group (CG) with 5-ASA 2 g/d alone, respectively, for 4 wk. Clinical changes were evaluated by Mayo scoring system and histological changes by Truelove-Richards' grading system at initial and final point of treatment.RESULTS: Forty-two patients completed the trial, 21 each in TG and CG. The Mayo scores in TG at initial and final points were 5.87 (range: 4.29-7.43) and 1.86 (range: 1.03-2.69) and those in CG were 6.05 (range: 4.97-7.13) and 2.57 (range: 1.92-3.22) respectively. The decrements of Mayo scores were 4.01 in TG and 3.48 in CG, with a remission rate of 71.4% in TG and 57.1% in CG, respectively. Along with the improvement of disease activity index (DAI), the histological grade improvement was more significant in TG than in CG (P < 0.05).CONCLUSION: Combined treatment with rosiglitazone and 5-ASA achieved better therapeutic effect than 5-ASA alone without any side effects. Rosiglitazone can alleviate colonic inflammation which hopefully becomes a novel agent for UC treatment.