Design, Synthesis, and Biological Evaluation of Novel Simvastatin Derivatives with Potent Lipid-Lowering Effects and HMG-CoA Reductase Inhibition in Hyperlipidemic Rats

Serum opacity factor (SOF) is a virulence determinant of group A streptococci that opacifies mammalian sera. We analyzed the specificity and mechanism of the opacity reaction using a recombinant form of the amino-terminal opacification domain of SOF, rSOF. Our data indicate that rSOF is neither a protease nor a lipase, but rather it is the binding of rSOF to high density lipoprotein (HDL) that triggers the opacity reaction. rSOF did not opacify plasma from apoA-I(-/-) mice or purified low or very low density lipoproteins but readily opacified HDL. rSOF binding to HDL was characterized by two high affinity binding sites; it bound to apoA-I (K(d) = 6 nm) and apoA-II (K(d) = 30 nm), and both apoA-I and apoA-II blocked the binding of rSOF to HDL. Electron microscopic examination and biochemical analyses of HDL treated with rSOF revealed the formation of lipid droplets devoid of apolipoproteins. Thus, SOF interacts with HDL in human blood by binding to apoA-I and apoA-II and causing the release of HDL lipid cargo, which coalesces to form lipid droplets, resulting in opacification. The disruption of HDL may attenuate its anti-inflammatory functions and contribute to the pathogenesis of group A streptococcal infections.

Isotopic tracers have been used to examine lipid trafficking for many years, and data from those studies have typically yielded novel insight regarding the pathophysiology of dyslipidemia. Previous experimental designs were suitable for studies in humans because relatively large volumes of plasma could be regularly sampled. We have expanded on the earlier logic by applying high-throughput analytical methods that require reduced sample volumes. Specifically, we have examined the possibility of coupling gel-based separations of lipoproteins (e.g., lipoprint) with LC-MS/MS analyses of complex lipid mixtures as a way to routinely measure the labeling profiles of distinct lipids in discrete lipoprotein subfractions. We demonstrate the ability to measure the incorporation of [U-(13)C]oleate into triglycerides (TG), PLs (PL), and cholesterol esters (CE) in VLDL, LDL, and HDL particles in mice. Although rodent models of dyslipidemia are inherently different from humans because of alterations in enzyme activities and underlying metabolism, rodent models can be used to screen novel compounds for efficacy in altering a given biochemical pathway and therein enable studies of target engagement in vivo. We expect that it is possible to translate our approach for application in other systems, including studies in humans.

FABP4 plasma levels are increased in familial combined hyperlipidemia

Separation of lipoproteins by traditional sequential salt density floatation is a prolonged process ( approximately 72 h) with variable recovery, whereas iodixanol-based, self-generating density gradients provide a rapid ( approximately 4 h) alternative. A novel, three-layered iodixanol gradient was evaluated for its ability to separate lipoprotein fractions in 63 subjects with varying degrees of dyslipidemia. Lipoprotein cholesterol, triglycerides, and apolipoproteins were measured in 21 successive iodixanol density fractions. Iodixanol fractionation was compared with sequential floatation ultracentrifugation. Iodixanol gradient formation showed a coefficient of variation of 0.29% and total lipid recovery from the gradient of 95.4% for cholesterol and 84.7% for triglyceride. Recoveries for VLDL-, LDL-, and HDL-cholesterol, triglycerides, and apolipoproteins were approximately 10% higher with iodixanol compared with sequential floatation. The iodixanol gradient effectively discriminated classic lipoproteins and their subfractions, and there was evidence for improved resolution of lipoproteins with the iodixanol gradient. LDL particles subfractionated by the gradient showed good correlation between density and particle size with small, dense LDL (<25.5 nm) separated in fractions with density >1.028 g/dl. The new iodixanol density gradient enabled rapid separation with improved resolution and recovery of all lipoproteins and their subfractions, providing important information with regard to LDL phenotype from a single centrifugation step with minimal in-vitro modification of lipoproteins.

در این آزمایش اثر افزودن سطوح مختلف اسانس اسطوخودوس Lavandula angustifolia)) به جیره بر عملکرد، فراسنجه‌های خونی و قابلیت هضم ایلئومی مواد مغذی در جوجه‌های گوشتی مطالعه گردید. برنامه تغذیه شامل جیره آغازین از 1 تا 10 روزگی، جیره رشد از 11 تا 24 روزگی و جیره پایانی از 25 تا 42 روزگی بود. پنج تیمار آزمایشی عبارت بودند از: تیمار شاهد، افزودن ویرجینیامایسین 10% به جیره) 50 میلی‌گرم در کیلوگرم( و سه سطح اسانس اسطوخودوس (350، 525 و700 میلی‌گرم در کیلوگرم). جوجه‌های تیمار حاوی ویرجینیامایسین در سن 42 روزگی بیشترین مصرف خوراک را داشتند و پس از آن جوجه‌های تغذیه شده با جیره‌های حاوی 525 و700 میلی‌گرم در کیلوگرم اسانس اسطوخودوس قرار داشتند. بیشترین افزایش وزن در کل دوره مربوط به جیره حاوی ویرجینیامایسین و کمترین افزایش وزن مربوط به جیره شاهد بود. در سن 28 روزگی کمترین میزان کلسترول خون در تیمار حاوی350 میلی‌گرم در کیلوگرم اسانس مشاهده شد که با تیمار آنتی بیوتیک اختلاف معنی‌داری داشت. همچنین جیره‌های حاوی اسانس اسطوخودوس باعث کاهش لیپوپروتئین با چگالی بالا سرم نسبت به جیره‌های حاوی ویرجینیامایسین و شاهد شدند. اثرات معنی‌داری بر ضریب تبدیل غذایی، تری گلیسرید، لیپوپروتئین با چگالی پایین، لیپوپروتئین با چگالی خیلی پایین سرم و قابلیت هضم مواد مغذی مشاهده نگردید. بر طبق نتایج این آزمایش اسانس اسطوخودوس باعث بهبود نتایج عملکردی در حد آنتی‌بیوتیک نگردید، اما استفاده از آن می‌تواند اثرات مثبتی بر مصرف خوراک، افزایش وزن و کاهش کلسترول داشته باشد، هر چند تحقیقات بیشتری در این زمینه مورد نیاز است.

The effect of aqueous extract of Irvingia wombolu seeds on lipid profile and atherogenic indices in hyperlipidemic wistar rats was evaluated. Forty five (45) wistar rats were grouped into five groups of nine rats each. The animals were allowed seven days acclimatization period. Group one was the control group and it received normal rat chow and water throughout the study. Groups 2 to 5 were given high fat diet for 14 days after which they were fed with normal rat chow till the end of the study. At the end of the 14 days, group 2 was not treated while group 3-5 were treated with 250, 500 and 1000mg/kg body weight aqueous extract of Irvingia wombolu seed respectively for 28 days. The lipid profile of animals was assayed three times: first after 14 days induction period (phase 1) i.e day 0 of treatment, second was taken 14 days after treatment (phase 2), third was taken 28 days after treatment (phase 3).The study lasted for 49 days and distilled water was used as a vehicle for the extract.In phase 1, there was a significant decrease (p&lt;0.05) in HDL (high density lipoprotein) level in all groups (2-5) compared to the control.there was a significant increase (p&lt;0.05) in LDL ( low density lipoprotein), Total cholesterol, Triglyceride, VLDL (very low density lipoprotein), Non HDL, Cardic risk factor, Atherogenic coefficient, Atherogenic index of plasma levels in all groups (2-5) compared to the control. All doses of aqueous extract of Irvingia wombolu seed were able to increase HDL level and decrease other lipid profile parameters and atherogenic indices in hyperlipidemic rats. Thus, aqueous extract of Irvingia wombolu seed has antidyslipidemic potential.

The relative contributions of lipoproteins and 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase to progesterone production by bovine granulosa cells exposed to plasma or liquor folliculi (LF) were studied. LF did not contain and very low density lipoprotein (VLDL), intermediate density lipoprotein (IDL), or low density lipoprotein (LDL). These lipoproteins were present in the plasma at concentrations of 92 micrograms protein/ml for VLDL and IDL together and 139 micrograms protein/ml for LDL. In contrast, high density lipoprotein (HDL) was present in LF at a concentration (763 micrograms protein/ml) that was 59% of that in plasma (1293 micrograms protein/ml). Bovine granulosa cells exposed to human plasma produce progesterone in response to dibutyryl cAmP. Sixty-three percent of the progesterone released by the cells was dependent on LDL but not HDL derived from human plasma. When cells were exposed to bovine plasma, 75% of the progesterone release was dependent on the presence of lipoproteins in the medium. Both LDL and HDL of bovine origin were able to support progesterone production, although LDL was effective at concentrations (on a molar basis) 20-fold lower than HDL. The LF was able to support progesterone production 45% as well as bovine plasma. The differences between the greater ability of the whole fractions and the lesser ability of their respective lipoprotein-deficient derivatives to support progesterone synthesis were 4-fold for bovine plasma, 2.7-fold for human plasma, and 1.7-fold for LF. The relative abilities of equivalent concentrations of LDL to restore the rate of progesterone synthesis seen in the lipoprotein-deficient fraction toward that seen in the whole fraction were greatest in the LF, intermediate in human plasma, and least in bovine plasma. These observations taken together suggest that the low level of support of progesterone synthesis that is offered by LF is due to its deficiency in LDL. HMG CoA reductase, the regulated and rate-limiting enzyme of cholesterol synthesis, was induced (2- to 3-fold) by dibutyryl cAMP and was suppressed by both human and bovine LDL and to a lesser extent by bovine HDL. Compactin, a competitive inhibitor of HMG CoA reductase, inhibited progesterone production relatively little when cells were exposed to complete plasma or LF. However, when cells were exposed to a lipoprotein-deficient bovine plasma or LF, compactin was very efficient in reducing (by 76%) progesterone release. Bovine granulosa cells exposed to plasma primarily use cholesterol derived from LDL in order to produce progesterone. Their ability to produce progesterone when exposed to LF was limited, and the cells were probably more dependent on de novo cholesterol synthesis than cells exposed to plasma.

Aim: To evaluate the effects of Pleurotus ostreatus on the lipid profile and atherogenic indices in Hyperlipidemic rats.&#x0D; Study Design, Place and Duration of Study: This case-control study was done for 60 days between March and April, 2017 at the department of Medical Laboratory Science and Department of Chemical Pathology, Babcock University, Ogun State, Nigeria.&#x0D; Methodology: Thirty male wistar rats weighing 117-130 g were divided randomly into 3 groups: Normolipidemic (NL) rats (fed with standard rodent chow), Hyperlipidemic (HL) rats (fed with standard rodent chow + duck yolk and reused oil), Hyperlipidemic Treated (HL+T) rats (fed with standard rodent chow + duck yolk and reused oil + 5% Pleurotus ostreatus powder). &#x0D; Changes in the animal body weights were measured in this study. Serum was obtained from fasting blood samples for the standard biochemical analyses of total cholesterol (TC), triglycerides (TG), High density lipoprotein cholesterol (HDL-C), creatinine, urea, Alanine aminotransferase (ALT) and Aspartate aminotransferase (AST). Low density lipoprotein (LDL), very low density lipoprotein (VLDL), TC/HDL, LDL/HDL and Log (TG/HDL) ratios were calculated.&#x0D; Results: The HL+T rats compared to HL rats had significantly reduced body weight, TC, TG, LDL, VLDL, TC/HDL, LDL/HDL and Log(TG/HDL) by 19.59%, 14.38%, 15.82%, 25.52%, 15.83%, 28.89%, 20.24% and 27.27% respectively (p ≤ 0.05) but recorded no significant change in HDL-C (p &gt; 0.05). Creatinine, urea, AST and ALT did not show any significant change in HL rats and HL+T rats (p &gt; 0.05).&#x0D; Conclusion: Treatment of hyperlipidemic male wistar rats with Pleurotus ostreatus reduced body weight, lipid levels (TC, TG, LDL, VLDL) and atherogenic indices (TC/HDL, LDL/HDL, Log (TG/HDL)) and appeared to have no detrimental effects on the liver and kidneys. These findings may provide insights and scientific basis for the promotion of the use of Pleurotus ostreatus in controlling hyperlipidemia and associated complications.

The effect of remnant lipoproteins on hepatic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and hepatic very low density lipoprotein (VLDL) secretion was studied in the perfused rat liver and in vivo. As had been observed previously, when the liver was perfused with a lipid-free medium, HMG-CoA reductase activity increased about twofold after 150 min, and this increase could be prevented by the addition of chylomicron remnants to the medium. However, suppression below base line activity did not occur even with increasing amounts of remnant cholesterol. When chylomicron remnants prepared from triglyceride-rich particles were included in the medium, reductase activity was increased even above that in the control perfusions despite the fact that approximately the same amount of cholesterol was removed from these particles as from standard particles. In contrast, particles that were low in triglycerides and rich in cholesterol not only prevented the rise in reductase activity but inhibited it significantly below base line activity. Again, the total amount of cholesterol removed was the same as with the other types of particles. These results suggested that both the triglycerides and cholesterol exerted an effect on HMG-CoA reductase. Consistent with this hypothesis, a significant correlation was found between reductase activity and the ratio of triglycerides to cholesterol removed, but not to either alone. To explore the role of triglycerides further, the effect of these lipoprotein particles on VLDL secretion was determined. VLDL secretion was stimulated by both standard and triglyceride-rich remnants but not by triglyceride-poor remnants. The degree of stimulation with standard chylomicron was comparable to that induced by infusion of a comparable fatty acid load as oleic acid bound to albumin. In vivo a similar effect of these lipoproteins on HMG-CoA reductase activity was observed. Rats were injected with a lipoprotein bolus containing 7 mg of cholesterol, and reductase activity in the liver was measured 2 hr later. Standard chylomicrons and triglyceride-rich chylomicrons stimulated reductase to 157% and 187% of control activity, respectively, whereas cholesterol-rich VLDL suppressed reductase activity to 30% of control activity. These observations support the hypothesis that remnant lipoproteins have a dual effect on hepatic HMG-CoA reductase activity; the cholesterol in these lipoproteins suppresses hepatic reductase activity while the triglycerides concommitantly delivered stimulate reductase activity at least in part because they stimulate hepatic VLDL secretion. Therefore, the net response of hepatic HMG-CoA reductase to a particular dietary lipoprotein will depend upon the balance between the cholesterol and triglycerides carried to the liver.-Van Zuiden, P. E. A., S. K. Erickson, and A. D. Cooper. Effect of removal of lipoproteins of different composition on hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and hepatic very low density lipoprotein secretion.

Hepatic steatosis and very low density lipoprotein secretion: the involvement of apolipoprotein E

A comparison of lovastatin, an HMG-CoA reductase inhibitor, with gemfibrozil, a fibrinic acid derivative, in the treatment of patients with diabetic dyslipidemia

Low serum levels of high-density lipoprotein (HDL) are commonly encountered in patients with coronary artery disease (CAD). An example of this type of patient is a 42-year-old white man with a history of sudden-onset angina secondary to a 90% obstructive lesion along the proximal left anterior descending coronary artery. The family history was significant for his father, who died of a myocardial infarction (MI) at age 44 years. The patient underwent percutaneous transluminal angioplasty with stenting but developed in-stent restenosis. He underwent cutting balloon angioplasty and brachytherapy and was asymptomatic for approximately 6 months. The stent then developed a high-grade occlusion with recurrence of angina, and the patient required single-vessel bypass surgery. The patient’s baseline serum lipid profile revealed low-density lipoprotein (LDL) 128 mg/dL, HDL 27 mg/dL, and triglycerides 92 mg/dL. His lipoprotein(a), C-reactive protein, and homocysteine levels were normal. He was not hypertensive, had no impairment of glycemic control, and did not smoke. With a combination of simvastatin 40 mg and niacin (Niaspan; Kos Pharmaceuticals) 1000 mg daily, the patient’s lipid profile improved, with LDL 78 mg/dL, HDL 43 mg/dL, and triglycerides 60 mg/dL. Follow-up stress testing demonstrated normal myocardial perfusion, and the patient has been asymptomatic for 2 years. With few exceptions, low HDL is an independent risk factor for CAD in case-control and prospective observational studies. In contrast, high HDL levels are associated with longevity and are protective against the development of atherosclerotic disease. In the Framingham Study, risk for CAD increases sharply as HDL levels fall progressively below 40 mg/dL.1 In the Quebec Cardiovascular Study, for every 10% reduction in HDL, risk for CAD increased 13%.2 Many clinicians believe that low HDL is associated with increased CAD risk because it is a marker for hypertriglyceridemia and elevated remnant particle concentrations. The Prospective Cardiovascular Munster …

Very low density lipoproteins (VLDL) and low density lipoproteins (LDL) from human normolipemic plasma, and the VLDL, the intermediate density lipoprotein (IDL), and LDL from patients with Type III hyperlipoproteinemic plasma were tested for their abilities to suppress the activity of 3-hydroxy-3-methylglutaryl-Coenzyme A (HMG-CoA) reductase in cultured human fibroblasts from normal subjects and a Type III patient. Regulation of cholesterol synthesis in the fibroblasts of a patient with Type III hyperlipoproteinemia appears to be normal. VLDL from normal subjects, isolated by angle head ultracentrifugation (d < 1.006) or by gel filtration on BioGel A-5m, were about 5 times less effective than LDL in suppressing HMG-CoA reductase activity, based on protein content, in agreement with previous reports with normal fibroblasts. Zonal centrifugation of normal VLDL isolated by both methods showed that the VLDL contained IDL. Normal VLDL from the angle head rotor, refractionated by the zonal method, had little, if any, ability to suppress the HMG-CoA reductase activity in either normal or Type III fibroblasts. VLDL, IDL, and LDL fractionated by zonal ultracentrifugation from Type III plasma gave half-maximum inhibition at 0.2-0.5 mug of protein/ml, indistinguishable from the suppression caused by normal LDL. Type III VLDL did not suppress HMG-CoA reductase in mutant LDL receptor-negative fibroblasts. Zonally isolated VLDL obtained from one Type IV and one Type V patient gave half-maximal suppression at 5 and 0.5 mug of protein/ml, respectively. Molecular diameters and apoprotein compositions of the zonally isolated normal and Type III VLDL were similar; the major difference in composition was that Type III VLDL contained more cholesteryl esters and less triglyceride than did normal VLDL. The compositions and diameters of the Type IV and Type V VLDL were similar to normal VLDL. These findings show that the basic defect in Type III hyperlipoproteinemia is qualitatively different from the cellular defect found in familial hypercholesterolemia, since the regulation of HMG-CoA reductase activity is normal in Type III fibroblasts. The metabolic defect in hypertriglyceridemia is related to the triglyceriderich lipoproteins which, free of other lipoproteins, have an enhanced ability to interact with cultured fibroblasts to regulate HMG-CoA reductase activity. These studies suggest that, in hypertriglyceridemia, there is a mechanism for direct cellular catabolism of VLDL which is not functional for normal VLDL.

Lipoprotein metabolism in FIC1 deficiency due to ATP8B1 mutations has never been studied sufficiently. This study was performed to investigate the detailed lipoprotein metabolism in benign recurrent intrahepatic cholestasis (BRIC) caused by FIC1 deficiency. Lipoprotein profile and major lipoprotein regulators such as lecithin:cholesterol acyltransferase (LCAT), hepatic triglyceride lipase (HTGL), lipoprotein lipase, and cholesteryl ester transfer protein in a Japanese patient with BRIC were serially examined during a bout of cholestasis. Liver expression of farnesoid X receptor (FXR), which suppresses high-density lipoprotein (HDL) generation, was also examined. Hypercholesterolemia and lipoprotein X accumulation were never observed throughout this study. When the cholestasis was severe, triglyceride-rich low-density lipoprotein (LDL) accounted for most of the plasma lipoproteins whereas HDL was hardly detectable. Concurrently, activities of all regulators were decreased, together with decreases of the serum parameter for liver protein synthesis. In particular, suppressions of LCAT and HTGL activities were severe and greatly contributed to the appearance of triglyceride-rich LDL. As the cholestasis improved, this LDL gradually transformed into normal LDL with the recoveries of LCAT and HTGL activities. The activities of all regulators for the last 1 to 2 months were normal but HDL remained depleted. His liver showed low FXR expression compared with control livers. The present study showed an appearance of triglyceride-rich LDL due to suppressions of LCAT and HTGL activities and a depletion of HDL that is not able to be explained by lipoprotein regulators or FXR in our patient.

We compared the effects of streptozotocin (STZ) treatment on serum cholesterol and lipoprotein levels in spontaneously hyperlipidemic rats (HLR), a hereditary hyperlipidemic model animal, with those in Sprague-Dawley rats (SDR). The body weight of control SDR and HLR were increased continuously for 30 days. Both SDR and HLR lost their body weight after STZ administration. Glucose levels of SDR and HLR were significantly increased by STZ treatment. Insulin levels were markedly decreased in HLR compared with those in SDR. Serum cholesterol and triglyceride levels of HLR treated with STZ were significantly higher than those of untreated HLR. The increment of both levels in HLR was much larger than that in SDR. The high density lipoprotein (HDL) cholesterol level of the STZ-treated HLR was significantly lower than that of untreated HLR. In the STZ-treated HLR the intensities of both bands of the very low density lipoprotein (VLDL) and the low density lipoprotein (LDL) were higher than those in untreated HLR, while the intensity of any lipoprotein band remained unchanged between STZ-treated and control SDR. The atherogenic index (the ratio of total cholesterol level minus HDL cholesterol level of HDL cholesterol level) in the STZ-treated HLR was significantly high compared with that in other groups. The STZ-treated HLR showed the extremely hyperlipidemic state and this animal might be useful in experiments for the development of atherosclerosis or the drug evaluation for the agents used in hyperlipidemia.