Discovery of a Potent Nicotinic Acid Receptor Agonist for the Treatment of Dyslipidemia

相似文献   

Hypoxia exacerbates Ca-handling disturbances induced by very low density lipoproteins (VLDL) in neonatal rat cardiomyocytes

It is known that myocardium suffers serious alterations under ischemic conditions such as lipid overloading and electrophysiological alterations. However, it is unknown whether intracellular lipid accumulation and calcium dysfunction share common pathophysiological mechanisms under ischemia. The aims of this study were 1) to analyze the effect of normal and high doses of very low density lipoproteins (VLDL) on lipid content and calcium handling; 2) to investigate whether hypoxia modulates the effect of high VLDL doses; and 3) to identify potentially underlying mechanisms in cardiomyocytes. For this purpose, neonatal rat ventricular myocytes cultures were prepared from hearts of 3-4-day-old rats. High doses of VLDL that induced cholesteryl ester (CE) and triglyceride (TG) accumulation strongly reduced sarco(endo)plasmic reticulum Ca ATPase-2 (SERCA-2) expression, calcium transient amplitude and sarcoplasmic reticulum (SR) calcium loading. Interestingly, hypoxia, by upregulating VLDL-receptor expression (4.5-fold at 16 h) increased CE (1.5-fold) and TG (3-fold) cardiomyocyte content and exacerbated the negative effect of VLDL on SERCA-2 expression. Functionally, the hypoxic exacerbation of VLDL-mediated SERCA-2 downregulation was translated into a stronger decrease in calcium transient amplitude and SR calcium loading in myocytes exposed simultaneously to hypoxia and high VLDL. In conclusion, high VLDL doses alter calcium handling in cardiomyocytes and SERCA-2 play a pivotal role in the hypoxic exacerbation of VLDL-mediated effects on cardiac calcium handling. Potentiation of VLDL's effects under hypoxia is explained, at least in part, by hypoxic upregulation of the expression of VLDL-receptor.     

Lipid metabolism and HCV infection

Chronic infection by hepatitis C virus (HCV) can lead to severe liver disease and is a global healthcare problem. The liver is highly metabolically active and one of its key functions is to control the balance of lipid throughout the body. A number of pathologies have been linked to the impact of HCV infection on liver metabolism. However, there is also growing evidence that hepatic metabolic processes contribute to the HCV life cycle. This review summarizes the relationship between lipid metabolism and key stages in the production of infectious HCV.     

A comparative study between the effect of 17-β estradiol and antioxidants combination on some menopausal changes in oophorectomised rats

BackgroundAs oxidative stress is proposed to be responsible for many of the menopause associated disorders, antioxidants may play an important role in this situation. The aim of this work was to compare between the effects of oestrogen replacement therapy and antioxidant supplements of vitamin C and low dose of vitamin A on some menopause associated changes in oophorectomised rats.Materials and methodsForty albino female rats were divided into 4 groups: normal control group, oophorectomised group, oophorectomised group treated with 17-β estradiol (oophorectomised + E₂) and oophorectomised group treated with vitamins (oophorectomised + vit).The following were measured: total antioxidant (TAO) and malondialdehyde (MDA), lipid profile, serum insulin, glucose and homeostasis model assessment-insulin resistance (HOMA-IR), bone specific alkaline phosphatase (BALP), urinary hydroxyproline, weight gain and visceral fat.ResultsA positive correlation was found between MDA and low density lipoprotein-cholesterol (LDL) (r = 0.694 and P = 0.000), HOMA-IR (r = 0.691 and P = 0.000.) and BALP (r = 0.563 and P = 0.000) and urinary hydroxyproline level (r = 0.761 and P = 0.000). Those results denoted that OS might be a cause of dyslipidemia, insulin resistance and osteoporosis associated with menopause.Both E₂ and vitamins in oophorectomised rats led to a significant decrease in MDA (F = 33.402, P = 0.000), weight gain, visceral fat (F = 7.589, p = 0.000 and F = 3.748, P = .019, respectively), cholesterol (F = 40.748, P = 0.0001), LDL cholesterol (F = 55.168, P = 0.0001), and significant increase in HDL (F = 18.393, P = 0.0001) and TAO levels (F = 14.781, P = 0.000) compared to oophorectomised rats. Also, both treatments led to a significant decrease of HOMA-IR (F = 18.933, P = 0.000, respectively), BALP (F = 13.202, P = 0.000) and urinary hydroxylproline (F = 220.012, P = 0.000). An interesting finding was detected where oophorectomised rats showed a decrease in triglyceride level which was significantly increased by E₂ administration whereas antioxidant administration produced no change (F = 34.267, P = 0.0001).ConclusionOur results denote similar effects of both E₂ and antioxidant’ supplements (vitamin C and low dose vitamin A) administration in surgically induced menopause in rats regarding oxidative stress, weight gain, atherogenic lipid profile changes, insulin sensitivity and bone turnover. However differences between preclinical and clinical studies must be taken into consideration especially when moving from animal studies to clinical trials.     

Eriosema laurentii De Wild (Leguminosae) methanol extract has estrogenic properties and prevents menopausal symptoms in ovariectomized Wistar rats

Ethnopharmacological relevance

Eriosema laurentii De Wild (Leguminosae) is a medicinal plant used in West and Central Africa for different diseases. In Cameroon, this plant is used as a treatment for infertility, and various gynecological and menopausal complaints. However, despite this use as a natural remedy, the biological activity of Eriosema laurentii has not been studied until now.

Aim of study

In order to determine the potential use of this plant in gynecological conditions/disorders, we evaluated the estrogenic properties of a methanol extract of its aerial parts and its ability to prevent different menopausal health problems induced by bilateral oophorectomy.

Material and methods

Two approaches were used. In vitro, recombinant yeast systems were applied, featuring either the respective human receptors (ERα, AR, and PR) or into chromosome III integrated human aryl hydrocarbon receptor (AhR) and the respective reporter plasmid. In vivo, the investigation was carried out using the 3 days uterotrophic assay and 9 weeks oral treatment in ovariectomized rats.

Results

The results showed that the methanol extract of the aerial parts of Eriosema laurentii transactivated the estrogen receptor-α and displayed AhR agonistic activity but was neither androgenic nor progesteronic. In rats, the extract did not induce endometrium proliferation either in the 3-day or the 9-week treatment regimens, but induced vaginal stratification and cornification, prevented loss of femur bone mass, increased high density lipoprotein cholesterol (HDL-C), and reduced total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), TC/HDL-C ratio, LDL-C/HDL-C ratio and the atherogenic index of plasma (AIP).

Conclusion

These results suggest that the methanol extract of the aerial parts of Eriosema laurentii does not seem to have an undesirable influence on the endometrium but might prevent vaginal dryness and bone mass loss and improve the lipid profile.     

A new pure ω-3 eicosapentaenoic acid ethyl ester (AMR101) for the management of hypertriglyceridemia: the MARINE trial

ω-3 fatty acids reduce triglyceride (TG) levels, but corresponding increases in low-density lipoprotein cholesterol (LDL-C) levels may compromise achievement of lipid goals in patients with elevated cardiovascular risk. AMR101 is an investigational agent containing ≥96% of pure icosapent ethyl (the ethyl ester of eicosapentaenoic acid). The Phase III Multi-Center, Placebo-Controlled, Randomized, Double-Blind, 12-Week Study with an Open-Label Extension (MARINE) investigated the efficacy and safety of AMR101 in 229 patients with very high TG levels (≥500 mg/dl). AMR101 4 g/day significantly reduced median placebo-adjusted TG levels from baseline by 33.1% (p < 0.0001), and AMR101 2 g/day reduced TG levels by 19.7% (p = 0.0051). Changes in LDL-C were minimal and nonsignificant. AMR101 may offer substantial TG lowering without increases in LDL-C levels.     

甲状腺激素对血清脂类、脂蛋白胆固醇及~(125)I-LDL清除率的影响

观察了不同甲状腺功能状态下血清脂类、脂蛋白水平及对LDL清除率的影响。甲状腺素组的T-C,(VLDL+LDL)-C,TG及(VLDL+LDL)-C/HDL-C降低,HDL-C升高,~(125)I-LDL清除率增加。他巴唑组的T-C,(VLDL+LDL)-C,HDL-C,TG,及(VLDL+LDL)-C/HDL-C均升高,~(125)I-LDL清除率有下降趋势。提示体内甲状腺激素水平的变化对血清脂类及脂蛋白胆固醇的代谢有明显影响     

Sepharose 6B柱层析在高胆固醇膳食家兔异常脂蛋白研究中的应用

用 Sepharose 6B 柱层析法可将正常兔血浆中三种脂蛋白(VLDL、LDL 和 HDL)和高 Ch 兔血浆中两种致 As 性脂蛋白(β-VLDL 和异常 LDL)成功地分离,并对其层析行为作了动态观察。在致 As 过程中,β-VLDL 和 LDL 层析峰的位置前移,面积增大,提示:这些致 As 性脂蛋白颞粒大小和含量均不断地增加;脂质成份亦有明显变化,TG/Tch 及 Fc/CE 比值逐渐下降。     

人血浆载脂蛋白E的分离纯化及其抗血清制备

用短时间超速离心结合制备性 SDS 聚丙烯酰胺凝胶电泳纯化人血浆 apoE.以此纯品免疫家兔制备了单价兔抗人 apoE 抗血清,与常规方法相比,本法具有操作简单、费用低和提纯周期短等优点,是一种简单实用的方法。