Beneficial effect of laserpitin, a coumarin compound from Angelica keiskei, on lipid metabolism in stroke-prone spontaneously hypertensive rats

Recently, we found that 4-hydroxyderricin, one of the major chalcones in Angelica keiskei extract (an ethyl acetate extract from the yellow liquid of stems), suppressed increases in systolic blood pressure and reduced both serum very low-density lipoprotein levels and liver triglyceride content in stroke-prone spontaneously hypertensive rats (SHRSP). In the present study, we have isolated laserpitin, a characteristic coumarin, from the A. keiskei extract and examined the effect of dietary laserpitin on blood pressure and lipid metabolism in SHRSP. Six-week-old male SHRSP were fed diets containing 0.1% laserpitin for 7 weeks with free access to the diet and water. Bodyweight gain was reduced by dietary laserpitin after 4 weeks through to 7 weeks without any significant change in daily food intake. Serum total cholesterol, phospholipid and apolipoprotein (apo) E levels were significantly increased, which was due to significant increases in cholesterol, phospholipid and apoE contents in the low- and high-density lipoprotein (LDL and HDL, respectively) fractions. These results suggest that dietary laserpitin increases serum apoE-HDL levels. In the liver, significant decreases in relative liver weight and triglyceride content were found after treatment with laserpitin for 7 weeks. An investigation of hepatic mRNA expression of proteins involved in lipid metabolism indicated that a significant decrease in hepatic triglyceride lipase may be responsible for the increase in serum HDL levels and also indicated that a marked decrease in adipocyte determination and differentiation factor 1 may be responsible, at least in part, for the decrease in hepatic triglyceride content. In conclusion, dietary laserpitin produces increases in serum HDL levels, especially apoE-HDL, and decreases in the hepatic triglyceride content in SHRSP.     

Effects of dietary Angelica keiskei on lipid metabolism in stroke-prone spontaneously hypertensive rats

1. The effect of dietary Angelica keiskei on lipid metabolism was examined in stroke-prone spontaneously hypertensive rats (SHRSP). 2. Six-week-old male SHRSP were fed diets containing 0.2% A. keiskei extract (ethyl acetate extract from the yellow liquid of stems) for 6 weeks with free access to the diet and water. 3. Elevation of systolic blood pressure tended to be suppressed on and after 2 weeks; however, this effect was not statistically significant. 4. Serum levels of cholesterol and phospholipid in SHRSP were significantly elevated after treatment with A. keiskei extract and this effect was accompanied by significant increases in serum apolipoprotein (Apo) A-I and ApoE concentrations. These changes in the serum were due to increases in high-density lipoprotein (HDL) containing ApoA-I and ApoE. 5. In the liver, significant decreases in relative weight and triglyceride content were observed in SHRSP after treatment with A. keiskei extract. An investigation of mRNA expression of enzymes involved in hepatic triglyceride metabolism indicated a decreased level of hepatic Acyl-coenzyme A synthetase mRNA expression. 6. In conclusion, dietary A. keiskei produces elevation of serum HDL levels and a reduction of liver triglyceride levels in SHRSP.     

Beneficial effect of xanthoangelol, a chalcone compound from Angelica keiskei, on lipid metabolism in stroke-prone spontaneously hypertensive rats

1. Recently, we reported that 4-hydroxyderricin, one of the major chalcones in Angelica keiskei extract (ethyl acetate extract from the yellow liquid of stems), exerted hypotensive and lipid regulatory actions in stroke-prone spontaneously hypertensive rats (SHRSP). In the present study, we isolated xanthoangelol, another major chalcone in A. keiskei extract, and examined the effect of dietary xanthoangelol on blood pressure and lipid metabolism in SHRSP. 2. Six-week-old male SHRSP were fed diets containing 0.02% or 0.1% xanthoangelol (0.02 and 0.10 Xan, respectively) for 7 weeks, with free access to the diet and water. There were no significant changes in daily food intake, bodyweight or systolic blood pressure throughout the experimental period. Serum total cholesterol levels tended to decrease in the two experimental groups (albeit not significantly), which was due to a dose-dependent decrease in the cholesterol content of the low-density lipoprotein (LDL) fraction. These results suggest that dietary xanthoangelol decreases serum LDL levels. 3. In the liver, significant dose-dependent decreases in relative liver liver weight and total triglyceride content were seen in the 0.02 and 0.10 Xan groups. In addition, a significant decrease in total cholesterol content was found in the 0.10 Xan group, which may be due to an elevation of faecal cholesterol excretion in addition to the decrease in liver weight. 4. Investigation of the hepatic mRNA expression of proteins involved in lipid metabolism indicated that there was a significant increase in peroxisome proliferator-activated receptor (PPAR) alpha mRNA expression associated with the tendency for increases in acyl-coenzyme A (CoA) synthetase and acyl-CoA oxidase mRNA expression in the 0.10 Xan group, which may be responsible, at least in part, for the decrease in hepatic triglyceride content in the xanthoangelol-treated rats. In addition, a significant increase in LDL receptor mRNA expression in the 0.10 Xan group may be responsible, at least in part, for the decrease in serum LDL levels in the xanthoangelol-treated rats. 5. In conclusion, dietary xanthoangelol results in a reduction of serum LDL levels and decreases in total cholesterol and triglyceride contents in the liver of SHRSP. These beneficial effects are more effective following consumption of diet containing 0.10% xanthoangelol.     

Hypocholesterolaemic effects of an ethanol precipitate of Kabosu juice in stroke-prone spontaneously hypertensive rats fed a cholesterol-free diet

1. We have previously identified strong inhibitory effects of Kabosu (Citrus sphaerocarpa Hort.) juice precipitate (KJP) on cholesterol elevation in stroke-prone spontaneously hypertensive rats (SHRSP) fed a cholesterol diet. In the present study, to elucidate the hypocholesterolaemic mechanism, we examined the effect of dietary KJP on lipid metabolism by using SHRSP fed a cholesterol-free diet. 2. Compositions of the experimental diet containing 10% KJP powder were adjusted to those of the control diet. Seven-week-old male SHRSP were fed control or experimental diet for 2 weeks with free access to the diet and water. 3. Serum levels of cholesterol, phospholipid and triglyceride of the KJP group were significantly reduced, which was due to decreases in the very low-density lipoprotein (VLDL), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) fractions. 4. Serum concentrations of apolipoproteins A-I and E (apoA-I and E) of the KJP group were significantly lower than those of the control group, whereas no significant differences were observed in serum apoB and apoA-IV between the two groups. 5. In liver, there were no significant differences in the contents of lipids or relative liver weight between the two groups. The activity of microsomal cholesterol 7alpha-hydroxylase of the KJP group tended to increase, whereas that of microsomal acyl-coenzyme A : cholesterol acyltransferase was significantly reduced, compared with the control group. 6. These results indicate that dietary KJP produces reductions of serum lipid levels, which are due to reductions in VLDL, apoE HDL and apoA-I HDL, and may promote catabolism and excretion of hepatic cholesterol in SHRSP fed a cholesterol-free diet.     

安络化纤丸对大鼠高脂性脂肪肝的治疗作用

目的探讨安络化纤丸对大鼠高脂性脂肪肝的治疗作用。方法以连续饲以高脂饲料(基础饲料加10%猪油、2%胆固醇、0.5%胆酸钠、5%蛋黄)1个月的方法建立高脂性大鼠脂肪肝模型,造模成功后给予安络化纤丸治疗4周,观察一般情况及测定血清丙氨酸氨基转换酶(ALT)、天门冬氨酸氨基转换酶(AST)、总胆固醇(TC)和甘油三酯(TG)水平,测定肝匀浆TG、丙二醛(MDA)及肝组织超氧化物歧化酶(SOD)水平,并对大鼠肝脏行病理学检查。结果安络化纤丸可明显降低高脂性脂肪肝大鼠血清ALT、AST、TC和TG水平,降低肝组织TG含量,提高肝组织SOD活性,并降低肝组织MDA水平。安络化纤丸可显著改善高脂性脂肪肝大鼠肝组织的病理损害。结论安络化纤丸对大鼠高脂性脂肪肝有明显的治疗作用,其作用可能与其抗氧化作用有关。     

Hypolipidemic activity of cyclic imido alkyl ethers, thioethers, sulfoxides, and sulfones

N-Substituted alkyl ethers, thioethers, sulfoxides, and sulfones of cyclic imides (e.g., phthalimide, saccharin, 1,8-naphthalimide, succinimide, and 2,3-dihydrophthalazine-1,4-dione) were shown to have potent hypolipidemic activity at doses of 10 and 20 mg/kg/d in rodents. These N-substitutions afforded no improvement over other known N-substitutions (e.g., butyl, 3-butanone, or the propionic acid derivatives of phthalimide, saccharin, and 2,3-dihydrophthalazine-1,4-dione) compared with the respective parent compounds. However, 2-(methoxyethyl)-1H-benz[de]isoquinoline-1,3-(2H)dione (3a), 2-[2-methylsulfinyl]ethyl-1H-benz[de]isoquinoline-1,3-(2H)dione (3c), 1-(2-methylsulfinyl)-2,5-pyrrolidenedione (4c), and 1-(2-methoxyethyl-2,5-pyrrolidenedione (4a) significantly improved activity compared with parent compounds, as well as previously reported N-substituted analogues, reducing serum cholesterol levels and serum triglyceride levels by 40%. The thioether of succinimide afforded a 54% reduction of serum cholesterol and a 41% reduction of serum triglyceride levels in mice after 16 d. The alkyl thioethers of 1,8-naphthalimide and succinimide significantly lowered cholesterol levels in serum VLDL and LDL, while the alkyl thioethers of succinimide elevated HDL cholesterol content. Tissue lipids were reduced in the liver and aorta by these selected derivatives. The activities of regulatory enzymes in de novo synthesis of hepatic cholesterol and triglyceride were inhibited by the selected 1,8-naphthalimide derivatives. In situ cholesterol and cholic acid reabsorption from intestines were suppressed by the presence of the agents.     

Simvastatin and bezafibrate: Effects on serum lipoproteins and lecithin: Cholesterol acyltransferase activity in familial hypercholesterolaemia

Summary Sixteen subjects with familial hypercholesterolaemia were randomly assigned to treatment with simvastatin 20–40 mg/day (an inhibitor of 3-hydroxy-3-methylglutaryl CoA reductase) or with bezafibrate 600 mg/day (a clofibrate analogue) for 12 weeks.Both drugs produced significant reductions in serum and LDL cholesterol; mean percentage fall –30.5% and –38.1% (simvastatin) and –17.8% and –20.6% (bezafibrate), respectively. Both drugs also caused a decrease in VLDL cholesterol, while only bezafibrate decreased the serum and VLDL triglyceride levels and increased HDL cholesterol and serum apolipoprotein A-I and A-II levels. Serum apolipoprotein B fell by 33.3% (simvastatin) and 15.7% (bezafibrate). Simvastatin and bezafibrate produced significant increases in the mean fractional esterification rate of LCAT, by +124,1% and +20.6%, respectively.Thus simvastatin was clearly more effective than bezafibrate in lowering LDL by enhancing its turnover, but bezafibrate had specific effects on VLDL and HDL that might be favourable in combined treatment regimens.     

Aspects of cholesterol metabolism in normal and hypercholesterolemic Syrian hamsters. Influence of fenofibrate

This study reports the short-term effects of fenofibrate in golden Syrian hamsters receiving a standard or cholesterol enriched (0.5%) diet. In chow fed control animals, the plasma cholesterol (132 mg/dl) was transported essentially by LDL (27%) and HDL (56%). Conversely, the bulk of triglycerides (114 mg/dl) circulated in VLDL (54%). One week of hypercholesterolemic diet increased plasma cholesterol (+80%) and it is reflected in a 3.3-fold increase in VLDL, 2.8-fold in IDL, 1.6-fold in LDL and 1.5-fold in HDL, accompanied by a rise in cholesterol hepatic level by a factor of 4.5. 15 days of treatment with fenofibrate (300 mg/kg/d) produced a decrease in free plasma cholesterol (-21%) without modification in total cholesterol level in chow fed animals. In liver, cholesterol was reduced by 27% and triglycerides were raised by 58%. In animals receiving the hypercholesterolemic diet, fenofibrate increased hepatic and plasmatic triglyceride levels (55 and 54%, respectively), although it slightly reduced plasma cholesterol levels and more markedly the hepatic cholesterol content (-55%). In chow fed animals, cholesterol biosynthesis was decreased by fenofibrate treatment by 40%. The effects of fenofibrate on triglyceride levels are in contrast to experiences in other animal species, including man, and indicate a hypersecretion of chylomicrons and/or a hypersecretion of VLDL, although the explanations are not yet obvious. The results concerning cholesterol metabolism indicate similarities between man and hamster.     

The hypolipidemic activity of N(4-methyl-phenyl)diphenimide in rodents

N(4-Methyl-phenyl)diphenimide afforded potent hypolipidemic activity in rodents. Serum cholesterol levels were reduced 67% and serum triglyceride were lowered 66% in rats by the drug after two weeks administration orally at 20 mg/kg/day. Rate limiting enzymes in the de novo synthesis of lipids in the liver were suppressed by the drug. Cholesterol was also removed from the body due to the drug accelerating bile excretion. Lipids removed from the blood compartment were not deposited in the organs of the body. VLDL and LDL cholesterol content was significantly reduced in rats treated with the drug with marked increase in HDL cholesterol after two weeks of administration. These data suggest that the drug may be useful in hyperlipidemic states and atherosclerosis in man, thus, further investigation of this class of chemicals is warranted.     

Effect of silymarin and its polyphenolic fraction on cholesterol absorption in rats.

This study evaluated the influence of silymarin (SM) and polyphenolic fraction (PF) of silymarin on cholesterol absorption in rats fed on high cholesterol diet (HCD). HCD induced a remarkable increase in hepatic, plasma, VLDL and LDL cholesterol, a decrease in HDL cholesterol and an elevation in triacylglycerol (TAG) levels in plasma, VLDL and in the liver. SM and PF were administered as dietary supplements (1.0%) in HCD for 18 days. Intestinal cholesterol absorption was measured by dual-isotope plasma ratio method, which calculates percent of cholesterol absorption from the ratio of two labelled cholesterol doses, one given intragastrically (14C) and one intravenously (3H). Silymarin and PF significantly reduced cholesterol absorption in rats fed on HCD and caused significant decreases in plasma and VLDL cholesterol and content of cholesterol and TAG in the liver. The level of HDL cholesterol was significantly increased after silymarin, but not after administration of PF. The levels of TAG in plasma and VLDL were not affected by either silymarin or PF. These results suggest that the inhibition of cholesterol absorption caused by silymarin and its polyphenolic fraction could be a mechanism contributing to the positive changes in plasma cholesterol lipoprotein profile and in lipid content in liver.     

Synthesis and Pharmacological Studies of 3-Amino-2-methyl-1-phenylpropanones as Hypolipidemic Agents in Rodents

A series of 3-amino-2-methyl-1-phenylpropanones were synthesized and proven to have potent hypolipidemic activity in rodents by lowering both serum cholesterol and triglyceride levels at 8 mg/kg/day, i.p. and orally. Many of these analogs showed significantly higher activity than standard drugs, lovastatin and clofibrate at their therapeutic doses. 2-Methyl-3-(perhydroazepin-1-yl)-1-phenylpropanone (@!4), 3-(4-methylpiperazin-1-yl)-1-phenylpropanone ( 5 ), and 2-methyl-3-(4-pyrrolidinocarbonyl-methylpiperazin-1-yl)-1-(4-fluorophenyl) propanone ( 17 ) showed the best overall activities in lowering both serum cholesterol and triglyceride levels in CF₁ mice at 8 mg/kg/day after 16 days of treatment. Compounds 4, 5 , and 17 lowered serum cholesterol levels 63%, 58%, and 42%, respectively, after 16 days at 8 mg/kg/day i.p. These agents reduced the serum triglyceride levels by 33%, 37%, and 54%, respectively. In Sprague-Dawley rats these compounds also demonstrated significant serum lipid lowering effects by decreasing both serum cholesterol and triglyceride levels after 14 days of oral drug administration at 8 mg/kg/day. Compound 17 reduced the rat aorta cholesterol levels by 37%, triglyceride levels by 50%, and neutral lipid levels by 34% after 14 days of oral administration. These compounds lowered the chylomicron, VLDL, and LDL cholesterol and triglyceride levels while elevating the HDL cholesterol levels significantly. In hyperlipidemic rodents, these analogs also demonstrated significant serum lipid lowering effects but were less active than in normalipidemic rodents. The activities of some enzymes, such as mouse hepatic acetyl CoA synthetase, HMG CoA reductase, phosphatidylate phosphohydrolase, and hepatic lipoprotein lipase, were significantly reduced by these compounds.     

Lipoprotein lipids and apoproteins during beta-blocker administration: Comparison of penbutolol and atenolol

Summary Serum lipoprotein lipid and apoprotein concentrations were determined in 21 hypertensive men during administration of two beta-blockers, penbutolol or atenolol, for 6 months preceded by a 4 week placebo period. Post-heparin plasma lipoprotein lipase and hepatic lipase activities were also measured.There was a trend to an increase of triglyceride and VLDL triglyceride concentrations during penbutolol administration, but the changes were not significant. Penbutolol also increased the total cholesterol by 11% at 3 months (mainly due to increase of VLDL cholesterol), but this effect diminished at 6 months.Atenolol did not cause any significant change in the total cholesterol but increased HDL cholesterol by 7% at 1 month, the change being due to rise of the HDL₃. The HDL₃ accounted also for a significant decrease of HDL cholesterol seen in the men receiving penbutolol at 6 months. HDL₂ cholesterol as well as the LDL/HDL₂ cholesterol ratio remained unchanged in both groups.Neither drug consistently influenced the post-heparin plasma lipase activities or the serum apoprotein A or B concentrations.In contrast to an earlier study the results suggest that the clinically most important HDL subfraction, the HDL₂, remains unaffected during treatment with beta-blockers.     

海南狗牙花总生物碱对兔实验性动脉粥样硬化的影响

本文报告海南狗牙花总生物碱(以下称总碱)对实验性动脉粥样硬化兔血清、主动脉和肝脏脂质含量,以及对动脉粥样硬化的影响。总碱能明显降低血清胆固醇(S-Ch)和甘油三酯(S-TG)含量,增加血清高密度脂蛋白胆固醇(HDL-Ch)含量和游离胆固醇(FC)与胆固醇酯(CE)的比值;能使主动脉壁胆固醇含量降低,FC与CE的比值增加,亦能明显减轻动脉粥样硬化的发展。总碱对肝脏脂质含量无明显影响。     

4-苯基丁酸对果糖所致非酒精性脂肪肝的保护效应

目的探讨4-苯基丁酸(PBA)对饮用果糖所致小鼠非酒精性脂肪肝的保护作用。方法 48只♀ICR小鼠随机分为4组。对照组给予普通自来水喂养8周;果糖组给予30%果糖水溶液喂养8周;PBA组给予普通自来水喂养8周,最后2周经腹腔注射给予PBA(100 mg.kg-1);PBA+果糖组给予富含30%果糖水溶液喂养8周,最后2周经腹腔注射给予PBA(100 mg.kg-1)。各组小鼠均自由进食标准饲料。实验结束后立即剖杀小鼠,采集血清和肝组织,检测血清丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)、总胆固醇(TCH)、甘油三酯(TG)、高密度脂蛋白(HDL)、极低密度脂蛋白(VLDL)和肝脏组织TCH和TG;HE染色分析肝脏组织病理学改变;油红O染色分析肝脏脂质沉积。RT-PCR测定小鼠肝脏脂肪酸合成酶(fas)、乙酰辅酶A羧化酶(acc)和硬脂酰辅酶A去饱和酶-1(scd-1)mRNA表达。结果与对照组相比,果糖组小鼠血清和肝脏TG及肝脏TCH的含量明显升高;HE染色显示,果糖组小鼠肝细胞脂肪变性;油红O染色证实,果糖组小鼠肝脏有明显脂质沉积;进一步研究显示,与对照组相比,果糖组小鼠肝脏fas,acc和scd-1 mRNA水平均明显上调。果糖组与PBA+果糖组比较显示,PBA干预可明显降低血清、肝脏TG含量及肝脏TCH含量,减轻果糖引起的肝脏脂质沉积;抑制果糖引起的肝脏fas,acc和scd-1表达上调。结论 PBA对饮用果糖所致的小鼠非酒精性脂肪肝有保护作用。     

Possible biochemical mechanisms involved in the antihypertensive drug-induced changes in serum lipoproteins

The antihypertensive drug-induced changes in serum lipoproteins can be attributed to two major mechanisms, namely an increased hepatic lipoprotein synthesis and a disturbed lipoprotein catabolism. Thiazides, by inhibiting phosphodiesterase, increase the intracellular concentration of cyclic AMP leading to a stimulation of lipolysis. beta-Blockers may reduce the adenylate cyclase activity in liver cells, leading to a reduced inhibition of the liver triglyceride synthesis and a higher secretion of VLDL triglyceride particles. alpha-Blockade through phosphodiesterase inhibition and an increased cAMP level, can result in a blockade of the liver triglyceride synthesis and a reduced serum triglyceride concentration. Lipoprotein lipase activity is reduced by beta-blockers and stimulated by alpha-blockers, leading, respectively, to a lower and a higher plasma HDL cholesterol. Besides these two major mechanisms, a direct effect of antihypertensive drugs on intracellular cholesterol synthesis can also be postulated.     

Stroke-prone spontaneously hypertensive rats have reduced hydroxysteroid 17-β dehydrogenase 7 levels for low cholesterol biosynthesis

Reduced serum cholesterol content was recently reported to be one of the factors responsible for cerebral haemorrhage. Stroke-prone spontaneously hypertensive rats (SHRSP) are known to have lower serum cholesterol content than normotensive Wistar-Kyoto rats (WKY). We previously reported that lower levels of mevalonate pyrophosphate decarboxylase (MPD) and squalene epoxidase (SQE), which are associated with cholesterol biosynthesis in the liver, are involved in the low serum cholesterol content in SHRSP. Here, we investigate the levels of sterol 14-demethylase (CYP51), methylsterol monooxygenase (SC4MOL), and hydroxysteroid 17-β dehydrogenase 7 (HSD17B7), which contribute to the cholesterol synthesis pathway in the conversion of lanosterol to zymosterol, in SHRSP and WKY. The HSD17B7 mRNA levels in the liver of SHRSP were markedly lower than those in WKY, whereas no significant differences were observed in CYP51 and SC4MOL levels in the two types of rats. The relative levels of protein, heteronuclear RNA, and mRNA of HSD17B7 were also significantly lower in SHRSP than in WKY. The degradation rates of HSD17B7 were the same in SHRSP and WKY. The protein levels of HSD17B7 were not significantly reduced in tissues other than the liver, including the brain, lung, heart, spleen, kidney, and testis, in SHRSP. Moreover, HSD17B7 activity was significantly lower in SHRSP than in WKY. Thus, our results indicated that low protein levels and activity of HSD17B7 are responsible for the reduced cholesterol content in SHRSP, indicating that HSD17B7, along with MPD and SQE, is involved in the decreased cholesterol synthesis in the liver of SHRSP.     

Thymoquinone alleviates nonalcoholic fatty liver disease in rats via suppression of oxidative stress,inflammation, apoptosis

Nonalcoholic steatohepatitis (NAFLD) is a progressive form of liver disease that leads to advanced fibrosis. The present study was designed to assess the hepatoprotective effect of thymoquinone (TQ) on liver functions, insulin resistance, and PPAR-γ expression in NAFLD. Rats were divided into two main groups: one fed with normal rat chow diet and the other with high-fat high-cholesterol diet group for 6 weeks. Every group was subdivided into three subgroups (n?=?8): treated with saline, low dose TQ (10 mg/kg), high dose TQ (20 mg/kg). High fat high cholesterol diet caused marked liver damage as noted in histopathology and significant increase in liver index, liver enzymes. There was significant increase in the insulin resistance, serum cholesterol, triglyceride, PPAR-γ gene overexpression with significant decrease in HDL. Additionally, oxidative stress increased by measuring MDA associated with significant decrease in serum total antioxidant capacity. As markers of inflammation, hepatic TNF-α was significantly increased with decrease in IL10. Further, there was increase in BAX protein with decrease in Bcl as compared to control group. This model of 6 weeks high-fat high-cholesterol diet showed minimal fibrosis as noticed by increase MMP2 and Masson trichrome satin. Co-treatment with TQ improved all previous parameters. High dose was more effective, although mostly non-statistically significant. TQ may have a promising agent to improve hepatic steatosis, oxidative stress; inflammatory, apoptotic status, fibrosis and so prevent liver damage in patients with NAFLD. Although PPAR-γ was significantly under-expressed by TQ, insulin resistance was improved significantly suggesting a role of liver damage.     

Lipid-lowering properties of TAK-475, a squalene synthase inhibitor,in vivo and in vitro

1. Squalene synthase is the enzyme that converts farnesyl pyrophosphate to squalene in the cholesterol biosynthesis pathway. We examined the lipid-lowering properties of 1-[[(3R,5S)-1-(3-acetoxy-2,2-dimethylpropyl)-7-chloro-5-(2,3-dimethoxyphenyl)-2-oxo-1,2,3,5-tetrahydro-4,1-benzoxazepin-3-yl]acetyl]piperidine-4-acetic acid (TAK-475), a novel squalene synthase inhibitor. 2. TAK-475 inhibited hepatic cholesterol biosynthesis in rats (ED(50), 2.9 mg kg(-1)) and showed lipid-lowering effects in beagle dogs, marmosets, cynomolgus monkeys and Wistar fatty rats. 3. In marmosets, TAK-475 (30, 100 mg kg(-1), p.o., for 4 days) lowered both plasma non-high-density lipoprotein (HDL) cholesterol and triglyceride, but did not affect plasma HDL cholesterol. On the other hand, atorvastatin (10, 30 mg kg(-1), p.o., for 4 days) lowered the levels of all these lipids. A correlation between decrease in triglyceride and increase in HDL cholesterol was observed, and TAK-475 increased HDL cholesterol with a smaller decrease in triglyceride than did atorvastatin. 4. TAK-475 (60 mg kg(-1), p.o., for 15 days) suppressed the rate of triglyceride secretion from the liver in hypertriglyceridemic Wistar fatty rats, which show an enhanced triglyceride secretion rate from the liver compared with their lean littermates. 5. In HepG2 cells, TAK-475 and its pharmacologically active metabolite, T-91485, increased the binding of (125)I-low-density lipoprotein (LDL) to LDL receptors. 6. These results suggest that TAK-475 has clear hypolipidemic effects in animals via inhibition of hepatic triglyceride secretion and upregulation of LDL receptors, and that TAK-475 might increase HDL cholesterol by decreasing triglyceride. Thus, TAK-475 is expected to be useful for the treatment of dyslipidemia.     

安络化纤丸预防大鼠酒精性脂肪肝形成的作用

目的研究安络化纤丸对大鼠酒精性脂肪肝(AFLD)形成的预防作用。方法首先经灌胃给予大鼠安络化纤丸预防性治疗4周,后用连续灌服酒精加喂以特制饲料的方法制备大鼠AFLD模型,造模成功后观察一般情况及测定血清谷丙转氨酶(ALT)、谷草转氨酶(AST)、碱性磷酸酶(AKP)、甘油三酯(TG)水平,测定肝组织匀浆TG、丙二醛(MDA)及超氧化物歧化酶(SOD)水平,并对大鼠肝脏组织作病理学检查。结果安络化纤丸可明显降低AFLD大鼠血清ALT、AST、AKP、TG水平,降低肝组织TG含量,升高肝组织SOD活性,并降低肝组织MDA水平。肝组织病理学结果表明,安络化纤丸可显著改善AFLD大鼠肝组织的病理损害。结论安络化纤丸有预防大鼠AFLD形成的作用。     

Synthesis and Hypolipidemic Activity of 3-Imino-l-oxoisoindolines in Rodents

A series of substituted 3-imino-l-oxoisoindolines derivatives demonstrated significant hypolipidemic activity, lowering both serum cholesterol and triglycerides levels after 16 days of dosing at 20 mg/kg/ day ip in CF₁ mice. 2-Butyl-3-butylimino-l-oxoisoindoline lowered serum cholesterol levels 52% and serum triglyceride 42%. 2-Pentyl-3-imino-l-oxoisoindoline lowered serum cholesterol levels 42% and serum triglyceride 61%. These derivatives resulted in better activity than the parent compound, 3-imino-1-oxoisoindoline. These studies showed that compounds with N-alkyl substitution of nitrogen atoms in the ring and outside the ring possessed potent hypolipidemic activity at the low dose of 20 mg/kg/day ip in normolipidemic CF₁ mice. Studies with 2-butyl-3-butylimino-l-oxoisoinodine in rats showed that serum cholesterol was reduced 60% and serum triglyceride 43% after 14 days of dosing at 20 mg/kg/day, orally. Treatment with this agent lowered lipid levels in the liver and aorta tissue, with increases in lipid levels in the small intestine tissue. Higher levels of cholesterol and phospholipids were excreted in the feces of treated animals compared to the control. Cholesterol levels of the very low-density lipoprotein (VLDL) and high-density lipoprotein (HDL) fractions were reduced, whereas the HDL cholesterol levels were elevated significantly. This ratio of low-density lipoprotein (LDL) cholesterol:HDL cholesterol levels suggests that the agent may be effective in treating hyperlipidemic states in humans.