The role of purslane in modulating diverse effects of high fat diet on biochemical, histological, and molecular parameters of rats' liver / O papel da beldroega na modulação de diversos efeitos da dieta rica em gordura nos parâmetros bioquímicos, histológicos e moleculares do fígado de ratos

Abstract Consuming a high-fat diet causes a harmful accumulation of fat in the liver, which may not reverse even after switching to a healthier diet. Different reports dealt with the role of purslane as an extract against high-fat diet; meanwhile, it was necessary to study the potential role of fresh purslane as a hypolipidemic agent. This study is supposed to investigate further the potential mechanism in the hypolipidemic effect of fresh purslane, by measuring cholesterol 7a-hydroxylase (CYP7A1) and low-density lipoprotein receptor (Ldlr). Rats were divided into two main groups: the first one is the normal control group (n=7 rats) and the second group (n=28 rats) received a high fat diet for 28 weeks to induce obesity. Then the high fat diet group was divided into equal four subgroups. As, the positive control group still fed on a high fat diet only. Meanwhile, the other three groups were received high-fat diet supplemented with a different percent of fresh purslane (25, 50 and 75%) respectively. At the end of the experiment, rats were sacrificed and samples were collected for molecular, biochemical, and histological studies. Current study reported that, supplementation of fresh purslane especially at a concentration of 75% play an important role against harmful effects of high-fat diet at both cellular and organ level, by increasing CYP7A1 as well as Ldlr mRNA expression. Also, there were an improvement on the tested liver functions, thyroid hormones, and lipid profile. Fresh purslane plays the potential role as a hypolipidemic agent via modulation of both Ldlr and Cyp7A, which will point to use fresh purslane against harmful effects of obesity.

Resumo O consumo de uma dieta rica em gordura causa um acúmulo prejudicial de gordura no fígado, que pode não reverter mesmo após a mudança para uma dieta mais saudável. Diferentes relatórios trataram do papel da beldroega como um extrato contra uma dieta rica em gordura; entretanto, foi necessário estudar o papel potencial da beldroega fresca como agente hipolipemiante. Este estudo pretende investigar mais profundamente o mecanismo potencial no efeito hipolipidêmico da beldroega fresca, medindo o colesterol 7a-hidroxilase (CYP7A1) e o receptor de lipoproteína de baixa densidade (Ldlr). Os ratos foram divididos em dois grupos principais: o primeiro é o grupo controle normal (n = 7 ratos) e o segundo grupo (n = 28 ratos) recebeu dieta rica em gorduras por 28 semanas para induzir a obesidade. Em seguida, o grupo de dieta rica em gordura foi dividido em quatro subgrupos iguais. Como, o grupo de controle positivo ainda se alimentava apenas com dieta rica em gordura. Enquanto isso, os outros três grupos receberam dieta rica em gordura suplementada com diferentes porcentagens de beldroegas frescas (25%, 50% e 75%), respectivamente. Ao final do experimento, os ratos foram sacrificados e amostras coletadas para estudos moleculares, bioquímica e histológicos. O estudo atual relatou que a suplementação de beldroegas frescas, especialmente a uma concentração de 75%, desempenha papel importante contra os efeitos prejudiciais da dieta rica em gordura em nível celular e orgânico, aumentando a expressão de CYP7A1 e Ldlr mRNA. Além disso, houve melhora nas funções hepáticas testadas, nos hormônios tireoidianos e no perfil lipídico. Beldroegas frescas desempenham papel potencial como agente hipolipemiante por meio da modulação de Ldlr e Cyp7A, o que apontará para o uso de beldroegas frescas contra os efeitos nocivos da obesidade.

The role of purslane in modulating diverse effects of high fat diet on biochemical, histological, and molecular parameters of rats' liver / O papel da beldroega na modulação de diversos efeitos da dieta rica em gordura nos parâmetros bioquímicos, histológicos e moleculares do fígado de ratos

Consuming a high-fat diet causes a harmful accumulation of fat in the liver, which may not reverse even after switching to a healthier diet. Different reports dealt with the role of purslane as an extract against high-fat diet; meanwhile, it was necessary to study the potential role of fresh purslane as a hypolipidemic agent. This study is supposed to investigate further the potential mechanism in the hypolipidemic effect of fresh purslane, by measuring cholesterol 7a-hydroxylase (CYP7A1) and low-density lipoprotein receptor (Ldlr). Rats were divided into two main groups: the first one is the normal control group (n=7 rats) and the second group (n=28 rats) received a high fat diet for 28 weeks to induce obesity. Then the high fat diet group was divided into equal four subgroups. As, the positive control group still fed on a high fat diet only. Meanwhile, the other three groups were received high-fat diet supplemented with a different percent of fresh purslane (25, 50 and 75%) respectively. At the end of the experiment, rats were sacrificed and samples were collected for molecular, biochemical, and histological studies. Current study reported that, supplementation of fresh purslane especially at a concentration of 75% play an important role against harmful effects of high-fat diet at both cellular and organ level, by increasing CYP7A1 as well as Ldlr mRNA expression. Also, there were an improvement on the tested liver functions, thyroid hormones, and lipid profile. Fresh purslane plays the potential role as a hypolipidemic agent via modulation of both Ldlr and Cyp7A, which will point to use fresh purslane against harmful effects of obesity.

O consumo de uma dieta rica em gordura causa um acúmulo prejudicial de gordura no fígado, que pode não reverter mesmo após a mudança para uma dieta mais saudável. Diferentes relatórios trataram do papel da beldroega como um extrato contra uma dieta rica em gordura; entretanto, foi necessário estudar o papel potencial da beldroega fresca como agente hipolipemiante. Este estudo pretende investigar mais profundamente o mecanismo potencial no efeito hipolipidêmico da beldroega fresca, medindo o colesterol 7a-hidroxilase (CYP7A1) e o receptor de lipoproteína de baixa densidade (Ldlr). Os ratos foram divididos em dois grupos principais: o primeiro é o grupo controle normal (n = 7 ratos) e o segundo grupo (n = 28 ratos) recebeu dieta rica em gorduras por 28 semanas para induzir a obesidade. Em seguida, o grupo de dieta rica em gordura foi dividido em quatro subgrupos iguais. Como, o grupo de controle positivo ainda se alimentava apenas com dieta rica em gordura. Enquanto isso, os outros três grupos receberam dieta rica em gordura suplementada com diferentes porcentagens de beldroegas frescas (25%, 50% e 75%), respectivamente. Ao final do experimento, os ratos foram sacrificados e amostras coletadas para estudos moleculares, bioquímica e histológicos. O estudo atual relatou que a suplementação de beldroegas frescas, especialmente a uma concentração de 75%, desempenha papel importante contra os efeitos prejudiciais da dieta rica em gordura em nível celular e orgânico, aumentando a expressão de CYP7A1 e Ldlr mRNA. Além disso, houve melhora nas funções hepáticas testadas, nos hormônios tireoidianos e no perfil lipídico. Beldroegas frescas desempenham papel potencial como agente hipolipemiante por meio da modulação de Ldlr e Cyp7A, o que apontará para o uso de beldroegas frescas contra os efeitos nocivos da obesidade.

The role of purslane in modulating diverse effects of high fat diet on biochemical, histological, and molecular parameters of rats liver

Abstract Consuming a high-fat diet causes a harmful accumulation of fat in the liver, which may not reverse even after switching to a healthier diet. Different reports dealt with the role of purslane as an extract against high-fat diet; meanwhile, it was necessary to study the potential role of fresh purslane as a hypolipidemic agent. This study is supposed to investigate further the potential mechanism in the hypolipidemic effect of fresh purslane, by measuring cholesterol 7a-hydroxylase (CYP7A1) and low-density lipoprotein receptor (Ldlr). Rats were divided into two main groups: the first one is the normal control group (n=7 rats) and the second group (n=28 rats) received a high fat diet for 28 weeks to induce obesity. Then the high fat diet group was divided into equal four subgroups. As, the positive control group still fed on a high fat diet only. Meanwhile, the other three groups were received high-fat diet supplemented with a different percent of fresh purslane (25, 50 and 75%) respectively. At the end of the experiment, rats were sacrificed and samples were collected for molecular, biochemical, and histological studies. Current study reported that, supplementation of fresh purslane especially at a concentration of 75% play an important role against harmful effects of high-fat diet at both cellular and organ level, by increasing CYP7A1 as well as Ldlr mRNA expression. Also, there were an improvement on the tested liver functions, thyroid hormones, and lipid profile. Fresh purslane plays the potential role as a hypolipidemic agent via modulation of both Ldlr and Cyp7A, which will point to use fresh purslane against harmful effects of obesity.

Resumo O consumo de uma dieta rica em gordura causa um acúmulo prejudicial de gordura no fígado, que pode não reverter mesmo após a mudança para uma dieta mais saudável. Diferentes relatórios trataram do papel da beldroega como um extrato contra uma dieta rica em gordura; entretanto, foi necessário estudar o papel potencial da beldroega fresca como agente hipolipemiante. Este estudo pretende investigar mais profundamente o mecanismo potencial no efeito hipolipidêmico da beldroega fresca, medindo o colesterol 7a-hidroxilase (CYP7A1) e o receptor de lipoproteína de baixa densidade (Ldlr). Os ratos foram divididos em dois grupos principais: o primeiro é o grupo controle normal (n = 7 ratos) e o segundo grupo (n = 28 ratos) recebeu dieta rica em gorduras por 28 semanas para induzir a obesidade. Em seguida, o grupo de dieta rica em gordura foi dividido em quatro subgrupos iguais. Como, o grupo de controle positivo ainda se alimentava apenas com dieta rica em gordura. Enquanto isso, os outros três grupos receberam dieta rica em gordura suplementada com diferentes porcentagens de beldroegas frescas (25%, 50% e 75%), respectivamente. Ao final do experimento, os ratos foram sacrificados e amostras coletadas para estudos moleculares, bioquímica e histológicos. O estudo atual relatou que a suplementação de beldroegas frescas, especialmente a uma concentração de 75%, desempenha papel importante contra os efeitos prejudiciais da dieta rica em gordura em nível celular e orgânico, aumentando a expressão de CYP7A1 e Ldlr mRNA. Além disso, houve melhora nas funções hepáticas testadas, nos hormônios tireoidianos e no perfil lipídico. Beldroegas frescas desempenham papel potencial como agente hipolipemiante por meio da modulação de Ldlr e Cyp7A, o que apontará para o uso de beldroegas frescas contra os efeitos nocivos da obesidade.

G protein-coupled receptor 35 attenuates nonalcoholic steatohepatitis by reprogramming cholesterol homeostasis in hepatocytes

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. Fat accumulation "sensitizes" the liver to insult and leads to nonalcoholic steatohepatitis (NASH). G protein-coupled receptor 35 (GPR35) is involved in metabolic stresses, but its role in NAFLD is unknown. We report that hepatocyte GPR35 mitigates NASH by regulating hepatic cholesterol homeostasis. Specifically, we found that GPR35 overexpression in hepatocytes protected against high-fat/cholesterol/fructose (HFCF) diet-induced steatohepatitis, whereas loss of GPR35 had the opposite effect. Administration of the GPR35 agonist kynurenic acid (Kyna) suppressed HFCF diet-induced steatohepatitis in mice. Kyna/GPR35 induced expression of StAR-related lipid transfer protein 4 (STARD4) through the ERK1/2 signaling pathway, ultimately resulting in hepatic cholesterol esterification and bile acid synthesis (BAS). The overexpression of STARD4 increased the expression of the BAS rate-limiting enzymes cytochrome P450 family 7 subfamily A member 1 (CYP7A1) and CYP8B1, promoting the conversion of cholesterol to bile acid. The protective effect induced by GPR35 overexpression in hepatocytes disappeared in hepatocyte STARD4-knockdown mice. STARD4 overexpression in hepatocytes reversed the aggravation of HFCF diet-induced steatohepatitis caused by the loss of GPR35 expression in hepatocytes in mice. Our findings indicate that the GPR35-STARD4 axis is a promising therapeutic target for NAFLD.

Effect of Shuangyu Tiaozhi Decoction on SRB1/CYP7A1/FXR Signaling Pathway in Liver of Hypercholesterolemic Rats / 中国实验方剂学杂志

Objective:To observe the effect of Shuangyu Tiaozhi decoction on B-type scavenger receptor （SRB1）/cholesterol 7<italic>α</italic>-hydroxylase protein （CYP7A1）/farnesol X receptor （FXR） signaling pathway in liver of hypercholesterolemic rats， and its mechanism in reducing blood lipid. Method:Among 40 SD rats， 8 were randomly selected as normal group， and the remaining 32 were successfully established as hypercholesterolemic model， and randomly divided into 4 groups： model group， low and high-dose Shuangyu Tiaozhi decoction groups （7.8， 15.6 g·kg^-1）， and simvastatin group （4 mg·kg^-1）， with 8 rats in each group. The drugs were continuously given for 8 weeks. Serum total cholesterol （TC）， triglyceride （TG） and liver TC，free cholesterol （FC） and total bile acid （TBA） were measured. The pathomorphological changes in liver were observed by Hematoxylin and eosin （HE） Staining. The mRNA and protein expressions of SRB1， CYP7A1 and FXR were determined by Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot. The immunohistochemistry was used to detect CYP7A1 and FXR expressions in liver. Result:Compared with the normal group， TC， TG， FC levels in the model group were significantly increased， while the TBA level was markedly decreased， the morphology showed obvious liver steatosis， and significant declines in expressions of SRB1， CYP7A1， FXR were observed by Real-time PCR， Western blot and immunohistochemistry assays （<italic>P</italic><0.05， <italic>P</italic><0.01）. Compared with the model group， the levels of TC，TG，FC in each treatment group were reduced significantly， and the TBA level was increased markedly， the liver steatosis decreased significantly， the results of Real-time PCR， Western blot and immunohistochemistry assays showed significant increase in the expressions of SRB1， CYP7A1， FXR （<italic>P</italic><0.05， <italic>P</italic><0.01）. The therapeutic effect of high-dose Shuangyu Tiaozhi decoction group was more remarkable than that in low-dose Shuangyu Tiaozhi Decoction group （<italic>P</italic><0.05）， with no obvious difference compared with simvastatin group. Conclusion:Shuangyu Tiaozhi decoction can promote hepatic RCT and synthesize bile acid by up-regulating SRB1/CYP7A1/FXR signaling pathway， so as to reduce the blood lipid levels and improve hepatic lipid metabolism of hypercholesterolemic rats.

Knockout of NLRP3 enhances hypolipidemic effect and anti-inflammative effect of apigenin in Triton-WR 1339-induced hyperlipidemia mice / 中国药理学通报

Aim To investigate the role and mechanism of NLRP3 on hypolipidemic effect and anti-inflammative effect of apigenin. Methods Triton-WR 1339-induced hyperlipidemia was applied to wide type C57BL/6 and NLRP3"'" mice, which was treated with apigenin of 6.25 mg • kg"1 • day"1 for five days. Blood and liver tissueswere collected for detecting TC, TG, HDL, LDL, IL-1B, IL-6, MCP-1 and the liver underwent HE staining. The expressions of NLRP3, I L 4, ASC, CD36, CYP7A1 and FGF21 were tested using RT-qPCR. Results Compared with NLRP3 "'" model group, serum contents of TC, TG, HDL, LDL, IL-1B, IL-6, MCP-1 were reduced in NLPR3"'" treated with apigenin of 6. 25 mg • kg"1 (P < 0. 05). The percentage of hepatic steatosis wasdown-regulated by apigenin in pathogenesis observation. However, all these phenotype changes were not observed in WT mice treated with apigenin. Moreover, up-regulation of CD36 and vLDLR and down-regualtion of ASC and IL-4 were founded in both WT and NLRP3"'" model group (P < 0. 05), while down-regulation of FGF21 and up-regulation of CYP7A1 were only seen in NLRP3"/ _ model group but not in WT group. Conclusions Knockout of NLRP3 enhances hypolipidemic effect and anti-inflammative effect of apigenin in triton-1339 IP-induced hyperlipidemia mice, which may be associated with apigenin-regulated FGF21/CYP7A1 pathway without NLRP3 inflammasome interruption.

Biochemistry and Molecular Biology of Mechanisms of Action of Fibrates – An Overview

Fibrates are a class ofmedication that mainly lowers theblood triglyceride levels. Theyreduce the LDL andincrease the levels of HDL C, in the blood.Clofibrate,the first member to bediscovered in 1962, and introduced in USA in 1967, is withdrawnin 2002, due to unexplained hepatomegaly,hepato-toxicity and possible risk of hepatic cancer. Other fibrates are introduced in the late 1970s and early1980s, such as gemfibrozil in the United States and bezafibrate and ciprofibrate in Europe. Their lipid lowering effects are found to decrease CVS risk , progression of atherosclerosis and metabolic syndrome, macrovascular and microvascular diabetic complications like stroke, myocardial infarction, peripheral vascular diseaseand diabeticretinopathy .Various clinical trials like VA-HIT trial (Veterans Affairs High-Density LipoproteinCholesterol Intervention Trial) , FIELD trail. (the Fenofibrate Intervention and Event Lowering in Diabetes) Helsinki Heart Study,ACCORD -Lipid trial (The lipid component of the Action to Control Cardiovascular Risk in Diabetes trial ) and BIP (Bezafibrate Infarction Prevention Study) trial andangiography trials, like LOCAT(LopidCoronary Angiography Trial) and BECLAIT(Bezafibrate Coronary Atherosclerosis Intervention Trial)demonstrated thebeneficial effects of gemfibrozil and fenofibrate.Their mechanism of action remained obscure for three decades,ie till 1990s, when theirmode of actionwas found. The Mechanism of action of fibrates include limitation of substrate availability for triglyceride synthesis in the liver, promotion of the action of lipoprotein lipase, (LPL)modulation of low density lipoprotein receptor/ligand interaction and stimulation of reverse cholesterol transport The biochemical and molecular mechanisms involvingthevariousenzymes like LCAT (Lecithin-cholesterol acyl transferase)andCYP7A1 etc. (cholesterol 7-alpha-monooxygenase or cytochromeP450 7A1 (CYP7A1)) , transporters like ABC , CETP (ATP-binding cassette transporter, Cholesterol ester binding protein) and NTCP,OATP (Na+-dependent taurocholate transporter/ organic anion transporters) . These are the.) andnuclear factors like LXR, PPAR alfa etc. (liver orphan receptorα , and peroxisome proliferative nuclear factor) , in relation to the mechanismsof action of fibrates are discussed . Areas of current interests in literature are briefed.

Effects of electroacupuncture on CYP7A1 expression in liver of rabbits with atherosclerosis / 中国针灸

OBJECTIVE@#To observe the effects of electroacupuncture (EA) at "Neiguan" (PC 6), "Guanyuan" (CV 4) and "Zusanli" (ST 36) on CYP7A1 expression in liver of rabbits with atherosclerosis (AS), and to explore the mechanism of acupuncture for prevention and treatment of atherosclerosis.@*METHODS@#A total of 26 male rabbits were adaptively fed for 1 week in different cages. Seven rabbits were randomly divided into a blank group, and the remaining 19 rabbits were divided into a model group. The blank group was fed with normal diet, while the model group was fed with high-fat diet. After high-fat diet for 4 weeks, the rabbits in the model group were treated with balloon injury surgery of the common carotid artery; after surgery, the rabbits were fed with high-fat diet for 4 weeks. One rabbit was randomly selected from the blank group and model group to obtain the pathological section of carotid artery; the HE staining was used to observe the pathomorphology of atheromatous plaque to determine the success of modeling or not. After successful establishment of modeling, 18 rabbits were randomly divided into a AS model group, an EA group and a medication group, 6 rabbits in each one. The rabbits in the AS model group received no treatment; the rabbits in the medication group were treated with intragastric administration of atorvastatin calcium tablets; the rabbits in the EA group were treated with EA at "Neiguan" (PC 6), "Guanyuan" (CV 4) and "Zusanli" (ST 36), once a day, 20 min per treatment; six-day EA treatment constituted one course, and totally 4 courses were given with an interval of 1 day between courses. After treatment, vein blood was collected from rabbit ear, and cholesterol (CHO), triglyceride (TG), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) were measured in each group; the CYP7A1 protein expression in rabbit liver was measured by Western blot method, and CYP7A1 mRNA expression in rabbit liver was measured by RT-PCR.@*RESULTS@#Compared with the blank group, the contents of CHO, TG and LDL in the AS model group were significantly increased, but HDL was significantly decreased, and the expression of CYP7A1 protein and CYP7A1 mRNA in the liver were significantly decreased (all 0.05).@*CONCLUSION@#EA could significantly improve blood lipid and promote the expression of CYP7A1 mRNA in rabbits with atherosclerotic, which may be one of the mechanisms of EA for atherosclerosis.

Berberine reverses LPS-induced repression of CYP7A1 through an anti-inflammatory effect / 中草药·英文版

Objective: To evaluate the anti-inflammatory effect of berberine (BBR) on the lipopolysaccharide (LPS)-induced acute phase response and its modulation of the altered bile acid metabolism induced by LPS treatment. Methods: An acute phase response was induced by intraperitoneal injection of LPS (5 mg/kg, ip) in C57BL/6 J mice, and the BBR treatment group was orally administered with BBR (200 mg/ky, ig). The levels of TNFα, IL-1β and IL-6 in the serum were measured using an ELISA kit, and their expression levels in the liver were measured using qRT-PCR. The bile acid pool was measured using a commercial bile acid kit, and the expression levels of enzymes involved in bile acid metabolism were measured by qRT-PCR. The expression levels of CYP7A1, p65 NF-κB and the MAPK signaling pathway was measured using Western blotting. Results: LPS treatment suppressed the expression of CYP7A1 and CYP8B1, and the total bile acid pool was also reduced. Pretreatment with BBR inhibited the pro-inflammatory biomarkers TNFα and IL-1β in the serum, as well as the expression of TNFα, IL-1β and iNOS mRNA in the liver. BBR treatment did not affect the reduction in the bile acid pool size induced by LPS, but significantly increased the concentration of bile acids in the liver, which was consistent with the upregulated expression of CYP7A1 and CYP8B1. The MAPK signaling pathway was activated by BBR treatment, while the p65 NF-κB signaling pathway was inhibited. Conclusion: BBR can offer an anti-inflammatory effect and reverse the inhibition of CYP7A1 and CYP8B1 expression caused by LPS treatment, as well as induce the production of bile acids in liver, probably via MAPK signaling; However, treatment with BBR had no effect on the size of total bile acid pool.

Advances in the development of farnesoid X receptor antagonists / 中国药科大学学报

@#Farnesoid X receptor(FXR), a member of the nuclear receptor superfamily, plays an important role on the regulating bile acid, lipid and glucose homeostasis. FXR antagonist can stimulate the conversion of total cholesterol into bile acid by improving the activity of CYP7A1. It can also reduce the content of triglyceride, low-density lipoprotein and increase that of high-density lipoprotein by regulating the relevant target genes. Considering the above facts, FXR antagonist is expected to become a potential drug to treat hyperlipidemia. In recent years, great progress has been made in the research on FXR antagonists with their various structural types having been obtained. This article introduces natural and synthetic FXR antagonists reported in recent years.

Effects of rifampicin on hepatotoxicity and genes related to bile acid metabolism in mice / 中国药理学通报

Aim Toexamineliverdamagebyrifampi-cin and hepatic gene expression related to bile acid me-tabolisminmice.Methods Adultmalemicewere given rifampicin(180 mg·kg-1 ,po)daily for 30 days and(90 mg·kg-1 ,po)daily for 90 days,blood bio-chemistry,histopathology,and gene expression were examined.Results Rifampicinincreasedanimalliver index and serum enzyme activities. Histopathology showed steatosis and spotted feathery-like degenera-tion.Rifampicin increased the expression of CYP7A1 after 30 and 90 days of administration,along with in-creased FXR and SHP.Rifampicin reduced the expres-sion of BSEP after 30 days of high dose administration. Conclusion Repeatedadministrationofrifampicin may cause liver injury and intrahepatic cholestasis in mice,and these effects are associated with the altera-tion of gene expression related to bile acid metabolism.

Bile Acid Diarrhea: Prevalence, Pathogenesis, and Therapy

Bile acid diarrhea (BAD) is usually seen in patients with ileal Crohn's disease or ileal resection. However, 25% to 50% of patients with functional diarrhea or diarrhea-predominant irritable bowel syndrome (IBS-D) also have evidence of BAD. It is estimated that 1% of the population may have BAD. The causes of BAD include a deficiency in fibroblast growth factor 19 (FGF-19), a hormone produced in enterocytes that regulates hepatic bile acid (BA) synthesis. Other potential causes include genetic variations that affect the proteins involved in BA enterohepatic circulation and synthesis or in the TGR5 receptor that mediates the actions of BA in colonic secretion and motility. BAs enhance mucosal permeability, induce water and electrolyte secretion, and accelerate colonic transit partly by stimulating propulsive high-amplitude colonic contractions. There is an increased proportion of primary BAs in the stool of patients with IBS-D, and some changes in the fecal microbiome have been described. There are several methods of diagnosing BAD, such as 75selenium homotaurocholic acid test retention, serum C4, FGF-19, and fecal BA measurement; presently, therapeutic trials with BA sequestrants are most commonly used for diagnosis. Management involves the use of BA sequestrants including cholestyramine, colestipol, and colesevelam. FXR agonists such as obeticholic acid constitute a promising new approach to treating BAD.

Biomarkers of hyperlipidemia cholesterol metabolism in hamster / 中国药理学通报

Aim To establish the hyperlipidemic model and ex-plore the mechanism of hypercholesterolemia in hamster. Meth-ods Hamsters were randomly divided into the control and model groups. The hamsters in the control group were fed with the standard chow and the model group were fed with the high fat di-et. Serum lipids and CYP7A1 activity were detected by enzymat-ic method. The molecular mechanism of cholesterol metabolism was investigated by real-time PCR. Results In comparison with the control group, the concentrations of serum TC, LDL-C, TG and hepatic TC, TG were significantly increased in the model group. The mechanism research showed that in hamsters fed with the high fat diet, the CYP7A1 activity and the mRNA expres-sions of hepatic LDL-R, SREBP-2, CYP7A1, LXRαwere down-regulated, the expression of hepatic FXR was up-regulated. Conclusion The hyperlipidemic model could be developed in hamsters fed with the high fat diet for 4 weeks. LDL-R, SREBP-2, CYP7A1, FXR and LXRαare the biomarkers of hypercholes-terolemia, and also the targets of hypolipidemic drugs.

The effect of fucoxanthin rich power on the lipid metabolism in rats with a high fat diet

This study determined the effects of fucoxanthin on gene expressions related to lipid metabolism in rats with a high-fat diet. Rats were fed with normal fat diet (NF, 7% fat) group, high fat diet group (HF, 20% fat), and high fat with 0.2% fucoxanthin diet group (HF+Fxn) for 4 weeks. Body weight changes and lipid profiles in plasma, liver, and feces were determined. The mRNA expressions of transcriptional factors such as sterol regulatory element binding protein (SREBP)-1c, Carnitine palmitoyltransferase-1 (CPT1), Cholesterol 7alpha-hydroxylase1 (CYP7A1) as well as mRNA expression of several lipogenic enzymes were determined. Fucoxanthin supplements significantly increased plasma high density lipoprotein (HDL) concentration (P < 0.05). The hepatic total lipids, total cholesterols, and triglycerides were significantly decreased while the fecal excretions of total lipids, cholesterol, and triglycerides were significantly increased in HF+Fxn group (P < 0.05). The mRNA expression of hepatic Acetyl-CoA carboxylase (ACC), Fatty acid synthase (FAS), and Glucose-6-phosphate dehydrogenase (G6PDH) as well as SREBP-1C were significantly lower in HF+Fxn group compared to the HF group (P < 0.05). The hepatic mRNA expression of Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) and Acyl-CoA cholesterol acyltransferase (ACAT) were significantly low while lecithin-cholesterol acyltransferase (LCAT) was significantly high in the HF+Fxn group (P < 0.05). There was significant increase in mRNA expression of CPT1 and CYP7A1 in the HF+Fxn group, compared to the HF group (P < 0.05). In conclusion, consumption of fucoxanthin is thought to be effective in improving lipid and cholesterol metabolism in rats with a high fat diet.

Hypocholesterolemic effects of curcumin via up-regulation of cholesterol 7a-hydroxylase in rats fed a high fat diet

There is an increasing interest in curcumin (Curcuma longa L.) as a cardiovascular disease (CVD) protective agent via decreased blood total cholesterol and low-density lipoprotein-cholesterol (LDL-cholesterol) level. The aim of this study was to investigate further the potential mechanism in the hypocholesterolemic effect of curcumin by measuring cholesterol 7a-hydroxylase (CYP7A1), a rate limiting enzyme in the biosynthesis of bile acid from cholesterol, at the mRNA level. Male Sprague-Dawley rats were fed a 45% high fat diet or same diet supplemented with curcumin (0.1% wt/wt) for 8 weeks. The curcumin diet significantly decreased serum triglyceride (TG) by 27%, total cholesterol (TC) by 33.8%, and LDL-cholesterol by 56%, respectively as compared to control group. The curcumin-supplemented diet also significantly lowered the atherogenic index (AI) by 48% as compared to control group. Hepatic TG level was significantly reduced by 41% in rats fed with curcumin-supplemented diet in comparison with control group (P < 0.05). Conversely, the curcumin diet significantly increased fecal TG and TC. The curcumin diet up-regulated hepatic CYP7A1 mRNA level by 2.16-fold, compared to control group p (P < 0.05). These findings suggested that the increases in the CYP7A1 gene expression may partially account for the hypocholesterolemic effect of curcumin.

Association of CYP7A1 -278A>C polymorphism and the response of plasma triglyceride after dietary intervention in dyslipidemic patients

We investigated the effect of the -278A>C polymorphism in the CYP7A1 gene on the response of plasma lipids to a reduced-fat diet for 6 to 8 weeks in a group of 82 dyslipidemic males with a mean age of 46.0 ± 11.7 years. Individuals who presented at least one high alteration in total cholesterol, low-density lipoprotein cholesterol or triglyceride values were considered to be dyslipidemic. Exclusion criteria were secondary dyslipidemia due to diabetes mellitus, renal, liver, or thyroid disease. None of the subjects were using lipid-lowering medication. Baseline and follow-up lipid concentrations were measured. The genotypes were determined by the digestion of PCR products with the BsaI restriction endonuclease. There were statistically significant reductions in plasma total cholesterol, low-density lipoprotein cholesterol and triglyceride concentrations after dietary intervention. The minor allele C has a frequency of 43 percent. Carriers of the C allele had significantly lower triglyceride concentrations (P = 0.02) than AA homozygotes. After adjustment of covariates, subjects with the AC and CC genotypes showed a greater reduction in triglyceride concentrations compared to subjects with the AA genotype. Multiple linear regression analyses showed that the AC and CC CYP7A1 genotypes accounted for 5.2 and 6.2 percent of triglyceride concentration during follow-up and adjusted percent of change of triglyceride concentration, respectively. The present study provides evidence that -278A>C polymorphism in the CYP7A1 gene can modify triglyceride concentrations in response to a reduced fat diet in a dyslipidemic male population. This gene represents a potential locus for a nutrigenetic directed approach.

Dietary chitosan enhances hepatic CYP7A1 activity and reduces plasma and liver cholesterol concentrations in diet-induced hypercholesterolemia in rats

The present study was performed to elucidate the hypocholesterolemic action of chitosan on the diet-induced hypercholesterolemia in rats. Male Sprague-Dawley rats (n=24) were fed with chitosan-free diet (Control), diets containing 2% or 5% chitosan for 4 weeks. Hypercholesterolemia was induced by adding 1% cholesterol and 0.5% cholic acid to all diets. Body weight gain and food intake of rats did not differ among the groups. The chitosan treated groups showed significant improvement in the plasma concentration of total cholesterol and LDL-cholesterol compared to the control group (p<0.05). Also, the chitosan treated groups decreased the liver concentration of total lipid and total cholesterol compared to the control group (p<0.05). The activity of hepatic cholesterol 7alpha-hydroxylase (CYP7A1), the rate-limiting enzyme in the conversion of cholesterol to bile acids, was increased by 123% and 165% for the 2% or 5% chitosan diets, respectively. These findings suggest that enhancement of hepatic CYP7A1 activity may be a mechanism, which can partially account for the hypocholesterolemic effect of dietary chitosan in cholesterol metabolism.

The A-204C Polymorphism in CYP7A1 Gene Affects Its Promoter Activity / 中国生物化学与分子生物学报

cholesterol 7α-hydroxylase gene ( CYP7A 1 ) plays a key role in the catabolism of cholesterol into bile acids. To investigate whether the A-204C polymorphism in CYP7A1 gene affects the gene expression,using luciferase as the reporter gene, four recombinants were constructed by inserting forward or reverse sequence with A or C allele at the polymorphism site into the promoter-less vector pGL3-basic. The constructs were then transfected into four cell lines and the luciferase activity of each expression vector was examined by dual luciferase reporter gene assay system. The results showed that activities of the forward sequence of both genotypes were higher than that of reverse sequence. Promoter activity of the recombinants with A allele was about one third lower than that with C allele. According to the analysis with TRANSFAC database, there may exist a Zic3 binding site when there is the C allele at -204. Our study indicates that the A-204 C polymorphism in CYP7A1 promoter region decreases its promoter activity and thus represses the gene expression, possibly due to the lack of a potential Zic3 binding site.