Decreased Plasma Cholesterol Levels Research Articles

Abstract 2004: Sex Differences In Bile Acid Metabolism Impact Cholesterol Homeostasis And Cardiovascular Disease

Cardiovascular disease (CVD) remains the leading cause of death in the United States for both men and women, despite cholesterol-lowering drugs such as statins. Diets rich in cholesterol are well-known to contribute to disease progression. The absorption of dietary cholesterol is facilitated by liver-synthesized detergents called bile acids. We hypothesized that manipulating bile acid metabolism to reduce cholesterol absorption would result in decreased plasma cholesterol levels and protect from atherosclerosis. To alter the bile acid pool, we used liver-directed AAV-CRISPR to disrupt Cyp7a1, which catalyzes the rate-limiting step of bile acid synthesis. Consequently, we show that loss of CYP7A1 in adult male mice reduces the size of the bile acid pool. To study atherosclerosis, we co-disrupted Cyp7a1 concurrently with Low Density Lipoprotein Receptor ( Ldlr ) to induce hypercholesterolemia on a Western diet for 20 weeks. Loss of hepatic CYP7A1 in males reduced atherosclerosis and reduced cholesterol absorption. In stark contrast to what we observed in male mice, the absence of this rate limiting enzyme in female mice resulted in only a modest reduction in the bile acid pool. This blunted reduction in bile acids in female Cyp7a1 CRISPR mice was not sufficient to decrease cholesterol absorption, resulting in accumulation of cholesterol, and consequently increasing cardiovascular risk. We hypothesize that there is a female-specific mechanism to preserve bile acid production that operates in the absence of CYP7A1. We are currently in the process of testing candidate female-specific enzymes for bile acid production. These studies indicate new avenues by which female bile acid and cholesterol metabolism regulation differs from than that of males. The resulting differences in cardiovascular risk highlight the essential need for male- and female-specific personalized medicine approaches for cardiovascular disease prevention.

ILRUN Promotes Atherosclerosis Through Lipid-Dependent and Lipid-Independent Factors.

Common genetic variation in close proximity to the ILRUN gene are significantly associated with coronary artery disease as well as with plasma lipid traits. We recently demonstrated that hepatic inflammation and lipid regulator with ubiquitin-associated domain-like and NBR1-like domains (ILRUN) regulates lipoprotein metabolism in vivo in mice. However, whether ILRUN, which is expressed in vascular cells, directly impacts atherogenesis remains unclear. We sought to determine the role of ILRUN in atherosclerosis development in mice. For our study, we generated global Ilrun-deficient (IlrunKO) male and female mice on 2 hyperlipidemic backgrounds: low density lipoprotein receptor knockout (LdlrKO) and apolipoprotein E knockout (ApoeKO; double knockout [DKO]). Compared with littermate control mice (single LdlrKO or ApoeKO), deletion of Ilrun in DKO mice resulted in significantly attenuated both early and advanced atherosclerotic lesion development, as well as reduced necrotic area. DKO mice also had significantly decreased plasma cholesterol levels, primarily attributable to non-HDL (high-density lipoprotein) cholesterol. Hepatic-specific reconstitution of ILRUN in DKO mice on the ApoeKO background normalized plasma lipids, but atherosclerotic lesion area and necrotic area remained reduced in DKO mice. Further analysis showed that loss of Ilrun increased efferocytosis receptor MerTK expression in macrophages, enhanced in vitro efferocytosis, and significantly improved in situ efferocytosis in advanced lesions. Our results support ILRUN as an important novel regulator of atherogenesis that promotes lesion progression and necrosis. It influences atherosclerosis through both plasma lipid-dependent and lipid-independent mechanisms. These findings support ILRUN as the likely causal gene responsible for genetic association of variants with coronary artery disease at this locus and suggest that suppression of ILRUN activity might be expected to reduce atherosclerosis.

Synthetic lipoproteins based on apolipoprotein E coupled to fullerenol have anti-atherosclerotic properties.

Apolipoprotein E (apoE) is an anti-atherosclerotic protein associated with almost all plasma lipoproteins. Fullerenol (Full-OH) contains the fullerene hydrophobic cage and several hydroxyl groups that could be derivatized to covalently bind various molecules. Herein, we aimed to produce fullerenol-based nanoparticles carrying apoE3 (Full-apoE) and test their anti-atherosclerotic effects. Full-apoE nanoparticles were obtained from Full-OH activated to reactive cyanide ester fullerenol derivative that was further reacted with apoE protein. To test their effect, the nanoparticles were administered to apoE-deficient mice for 24h or 3weeks. ApoE part of the nanoparticles was determined by Western Blot and quantified by ELISA. Atherosclerotic plaque size was evaluated after Oil Red O staining and the gene expression was determined by Real-Time PCR. Full-apoE nanoparticles were detected mainly in the liver, and to a lesser extent in the kidney, lung, and brain. In the plasma of the Full-apoE-treated mice, apoE was found associated with very-low-density lipoproteins and high-density lipoproteins. Treatment for 3weeks with Full-apoE nanoparticles decreased plasma cholesterol levels, increased the expression of apolipoprotein A-I, ABCA1 transporter, scavenger receptor-B1, and sortilin, and reduced the evolution of the atheromatous plaques in the atherosclerotic mice. In experimental atherosclerosis, the administration of Full-apoE nanoparticles limits the evolution of the atheromatous plaques by decreasing the plasma cholesterol level and increasing the expression of major proteins involved in lipid metabolism. Thus, they represent a novel promising strategy for atherosclerosis therapy.

Intestinal Deletion of 3-Hydroxy-3-Methylglutaryl-Coenzyme A Reductase Promotes Expansion of the Resident Stem Cell Compartment.

The intestine occupies the critical interface between cholesterol absorption and excretion. Surprisingly little is known about the role of de novo cholesterol synthesis in this organ, and its relationship to whole body cholesterol homeostasis. Here, we investigate the physiological importance of this pathway through genetic deletion of the rate-limiting enzyme. Mice lacking 3-hydroxy-3-methylglutaryl-coenzyme A reductase (Hmgcr) in intestinal villus and crypt epithelial cells were generated using a Villin-Cre transgene. Plasma lipids, intestinal morphology, mevalonate pathway metabolites, and gene expression were analyzed. Mice with intestine-specific loss of Hmgcr were markedly smaller at birth, but gain weight at a rate similar to wild-type littermates, and are viable and fertile into adulthood. Intestine lengths and weights were greater relative to body weight in both male and female Hmgcr intestinal knockout mice. Male intestinal knockout had decreased plasma cholesterol levels, whereas fasting triglycerides were lower in both sexes. Lipidomics revealed substantial reductions in numerous nonsterol isoprenoids and sterol intermediates within the epithelial layer, but cholesterol levels were preserved. Hmgcr intestinal knockout mice also showed robust activation of SREBP-2 (sterol-regulatory element binding protein-2) target genes in the epithelium, including the LDLR (low-density lipoprotein receptor). At the cellular level, loss of Hmgcr is compensated for quickly after birth through a dramatic expansion of the stem cell compartment, which persists into adulthood. Loss of Hmgcr in the intestine is compatible with life through compensatory increases in intestinal absorptive surface area, LDLR expression, and expansion of the resident stem cell compartment.

IL-2Rβγ signalling in lymphocytes promotes systemic inflammation and reduces plasma cholesterol in atherosclerotic mice

Background and aimsThe relationship between inflammation and lipid metabolism is complex and bidirectional. Lymphocyte-driven inflammation has been shown to modulate both atherosclerotic plaque development and cholesterol levels, but the mechanisms are incompletely understood. MethodsThe cardiometabolic effects of IL-2Rβγ signalling in atherosclerotic Apoe−/− mice were investigated by treatment with an agonistic IL-2Rβγ-targeting IL-2/anti-IL-2 complex or a monoclonal anti-CD122 (IL-2Rβ) blocking antibody. ResultsAdministration of IL-2Rβγ agonistic IL-2/anti-IL-2 complexes to Apoe−/− mice augmented opposing arms of the adaptive immune system. Expansion of effector/memory T cells and increased levels of circulating pro-inflammatory cytokines were observed along with elevated levels of regulatory T cells and IL-10. Notably, IL-2/anti-IL-2 treatment did not affect plaque size but decreased levels of plasma cholesterol. The cholesterol lowering effect of IL-2Rβγ agonism was not affected by anti-CD8 or anti-NK1.1 depleting antibody treatment but was contingent on the presence of adaptive immunity. Expression of multiple liver X receptor (LXR)-related genes, including Pltp and Srebp1c in the liver, was decreased by IL-2/anti-IL-2 treatment. Although IL-2Rβγ agonism lowered cholesterol levels, blocking IL-2Rβγ signalling using an anti-CD122 monoclonal antibody did not impact cholesterol levels or plaque burden in Apoe−/− mice. ConclusionsElevated IL-2Rβγ signalling results in activation of both inflammatory and regulatory lymphocytes with a net zero effect on atherosclerosis and decreased plasma cholesterol levels. Changes in cholesterol levels were associated with reductions in hepatic LXR-related gene expression. Further studies are needed to investigate the clinical significance of IL-2 mediated modulation of hepatic LXR signalling in inflammatory disorders.

Fluorescence-Based Detection of Cholesterol Using Inclusion Complex of Hydroxypropyl-β-Cyclodextrin and l-Tryptophan as the Fluorescence Probe

The study is inspired by the fact that intravenous administration of 2-hydroxypropyl-beta-cyclodextrins (HP-β-CD) in rats leads to a rapid decrease in plasma cholesterol levels. Further, HP-β-CD being more water soluble than native β-CD, HP-β-CD forms soluble complex with cholesterol and higher affinity of cholesterol towards HP-β-CD than native β-CD leads to increase sensitivity. Hence, present work reports potential use of HP-β-CD as a chemosensor to detect cholesterol aided with l-tryptophan (l-Trp) as a fluorescence probe. The purpose of the study is to develop fast, cost-effective, and high throughput fluorescence-based chemosensor as convenient point-of-care diagnostic method for cholesterol detection. The host-guest interaction of l-Trp with HP-β-CD was elaborately studied using characterization techniques such as FT-IR, NMR, and DSC. Time and concentration dependent interactions were studied to determine the stoichiometry of molecular inclusion complexes of HP-β-CD with l-Trp. Further, the inclusion complex of HP-β-CD with l-tryptophan is explored to detect cholesterol based on the competitive displacement phenomenon and further explored for detecting different concentrations of cholesterol. Fluorescence spectroscopic data revealed that HP-β-CD served as a quencher for l-Trp. Also, promising results of the displacement assay proved that the fluorescence of l-Trp was quenched by HP-β-CD followed by increase in fluorescence signals in quantitative relation with cholesterol as it replaces l-Trp from the HP-β-CD host. The present investigation is a proof-of-concept that proves the potential of HP-β-CD with l-Trp as a novel fluorescence–based technique for cholesterol detection which is developed using competitive host–guest interaction.

Male-biased fasting-induced changes inhepatic tauro-cholic acid and plasma cholesterolin Sult2a8-haplodeficient mice.

SULT2A8 is a male-predominant and liver-specific mouse cytosolic sulfotransferase (SULT) that sulfonates 7α-hydroxyl (7α-OH) bile acids in vitro. Sulfonation regulates bile acid homeostasis, which in turn regulates cholesterol and energy metabolism. Using the Sult2a8-heterozygous (HT) mouse model created earlier in our laboratory, we aimed to investigate the physiological role of SULT2A8 in sulfonating 7α-OH bile acids and its impact on energy metabolism in vivo under both fed and energy-deprivation conditions. Disruption of one allele of the Sult2a8 gene in male HT mice resulted in losing ~ 50% of the 7α-OH sulfonating activity compared to wild-type (WT) control, but no significant change in female HT mice. Under the fed condition comparing the levels of hepatic and biliary bile acids as well as plasma/serum energy metabolites, HT mice displayed a profile similar to that of WT mice, suggesting that the Sult2a8-haplodeficient mice conducted normal energy metabolism. However, after 48-h fasting, a significant decrease in plasma cholesterol level was found in male HT mice but without any significant reduction in female HT mice. Of interest, in male Sult2a8-haplodeficient mice, an increase of the hepatic taurine-conjugated cholic acid level was noted but no noticeable change in other tested bile acids after fasting. Taken together, SULT2A8 is a male-specific and key hepatic SULT in metabolizing 7α-OH primary bile acids. During energy deprivation, SULT2A8 is required to maintain the bile acid and cholesterol metabolism, suggesting SULT is a potential therapeutic target for controlling metabolic diseases.

Intestine-specific DGAT1 deficiency improves atherosclerosis in apolipoprotein E knockout mice by reducing systemic cholesterol burden

Background and aimsAcyl-CoA:diacylglycerol acyltransferase 1 (DGAT1) is the rate-limiting enzyme catalyzing the final step of triglyceride synthesis by esterifying a diglyceride with a fatty acid. We have previously shown that apolipoprotein E-knockout (ApoE−/−) mice lacking Dgat1 have reduced intestinal cholesterol absorption and potentiated macrophage cholesterol efflux, and consequently, exhibit attenuated atherogenesis. However, hematopoietic Dgat1 deficiency lacked beneficial effects on atherosclerosis. Due to our recent results on the critical role of intestinal Dgat1 in murine cholesterol homeostasis, we delineated whether intestinal Dgat1 deficiency regulates atherogenesis in mice. MethodsWe generated intestine-specific Dgat1−/− mice on the ApoE−/− background (iDgat1−/−ApoE−/−) and determined cholesterol homeostasis and atherosclerosis development. ResultsWhen fed a Western-type diet, iDgat1−/−ApoE−/− mice exhibited a substantial decrease in fasting plasma cholesterol content in ApoB-containing lipoproteins. Although lipid absorption was delayed, iDgat1−/−ApoE−/− mice had reduced acute and fractional cholesterol absorption coupled with an elevated fecal caloric loss. In line, increased appearance of i.v. administered [³H]cholesterol in duodena and stool of iDgat1−/−ApoE−/− animals suggested potentiated cholesterol elimination. Atherosclerotic lesions were markedly smaller with beneficial alterations in plaque composition as evidenced by reduced macrophage infiltration and necrotic core size despite unaltered collagen content, indicating improved plaque stability. ConclusionsDisruption of Dgat1 activity solely in the small intestine of ApoE−/− mice strongly decreased plasma cholesterol levels by abrogating the assimilation of dietary cholesterol, partly by reduced absorption and increased excretion. Consequently, the reduced cholesterol burden significantly attenuated atherogenesis and improved the lesion phenotype in iDgat1−/−ApoE−/− mice.

Effects of bezafibrate to high trans-fat diet (HTD) -induced nonalcoholic steatohepatitis (NASH) model in mice

We previously presented that bezafibrate (BF), a PPAR-pan agonist, has preventing and therapeutic effects on high fat and high cholesterol (HFHC) diet-induced nonalcoholic steatohepatitis (NASH) model in mice. In this study, we examined the effects of BF to high trans-fat diet (HTD) -induced NASH model in mice. HTD was fed to 7-week-old ob (spontaneously obese, hyperglycemia model) mice for 12 weeks to induce NASH. Half of ob mice were orally administered BF (100 mg/kg/day) for 12 weeks. Remaining ob mice were served as controls and administered the vehicle. Normal C57BL/6J mice were fed normal diet and administered the vehicle. After 12 weeks, plasma levels of AST, ALT, TC, glucose, and concentrations of hepatic TG, TC in ob mice fed HTD were markedly higher than those of normal mice. Fatty droplets, inflammation and fibrosis were observed in histopathologic examination of liver. BF significantly lowered plasma TC level, histopathologic fibrosis area and fibrosis scoring without effecting to plasma ALT levels. These results suggested that bezafibrate may suppress the progression of fibrosis in mice NASH model induced by HTD through a decrease in plasma cholesterol level or directly.

The Effect of Subdiaphragmatic Vagotomy on Lipid Profile and Insulin Resistance in Diabetic Obese Rats

The aim of the study was to assess of the effect of subdiaphragmatic vagotomy on lipid profile and insulin resistance in diabetic obese rat model. Fifty Male Albino rats were divided into 5 groups. Subdiaphragmatic vagotomy and sham operations were applied on diabetic obese rat model induced by high fat diet for 5 weeks and low dose of streptozotocin (30mg/kg). Serum samples were collected for confirmation of hyperlipidemia and lee obesity index was measured. At the end of the experiment, oral glucose tolerance test, lee obesity index, lipid profile, fasting insulinemia, fasting glucose, insulin resistance (HOMA-IR) and histopathology of pancreases were assessed. Results revealed that Subdiaphragmatic vagotomy significantly improved hyperlipidemia as it normalized plasma triglyceride level, decreased plasma cholesterol level and increased plasma high density lipoprotein level in diabetic and non-diabetic obese vagotomized rats. Vagotomy significantly decreased lee obesity index and perigonadal fat pads weight, decreased fasting insulinemia, decreased HOMA-IR and improved glucose tolerance in diabetic and non-diabetic obese vagotomized rats. These results were confirmed by regression of degenerative changes and restoration of the size of pancreatic islets of Langerhans. In non-diabetic obese vagotomized group, the results of 120 minutes of oral glucose tolerance test and HOMA-IR were close to normal expected values. However, the same parameters were still away from normal expected values although normal histopathological results of pancreases, in diabetic obese vagotomized group. In Conclusion, subdiaphragmatic vagotomy has a promising role in treating obesity. Nevertheless, its role in treating diabetes needs further long-term studies to be approved.

Long-term effects of maternal resveratrol intake during lactation on cholesterol metabolism in male rat offspring

Resveratrol (RSV) can protect against non-communicable diseases by improving cholesterol metabolism. However, it is unclear that effects of maternal RSV intake on health of adult offspring. In this study, we examined effects of maternal RSV intake during lactation on cholesterol metabolism in adult male rat offspring. Female Wistar rats were fed a control diet (CON) supplemented with or without RSV (20 mg/kg body weight/day) during their lactation period. Male offspring were weaned onto a standard diet and maintained on this diet for 36 weeks. As a result, plasma cholesterol level significantly decreased in RSV offspring compared to CON offspring. Furthermore, a decrease in hepatic 3-hydroxy-3-methylglutaryl-CoA reductase level and an increase in hepatic LDL-receptor level were observed in the RSV offspring. These results indicate that maternal RSV intake causes long-term decrease in plasma cholesterol level in the offspring through suppression of hepatic cholesterol biosynthesis and promotion of hepatic cholesterol uptake.

Non-Native Conformational Isomers of the Catalytic Domain of PCSK9 Induce an Immune Response, Reduce Lipids and Increase LDL Receptor Levels.

PCSK9 (Proprotein convertase subtilisin/kexin type 9) increases plasma cholesterol levels by promoting LDL receptor degradation. Current antibody inhibitors block the interaction between PCSK9 and LDL receptors, significantly decrease plasma cholesterol levels, and provide beneficial clinical outcomes. To reduce the action of PCSK9 in plasma, a novel strategy that will produce a panel of non-native, conformationally-altered isomers of PCSK9 (X-PCSK9) to develop active immunotherapy targeting of native PCSK9 and inhibiting/blocking the interaction of PCSK9 with LDL receptor, thus decreasing plasma cholesterol levels is proposed. The authors used the scrambled disulfide bond technique to generate conformationally-altered isomers of the catalytic domain of mouse PCSK9. The focus was on the immune response of four X-isomers and their effects on plasma cholesterol and triglyceride levels in both C57BL/6J and Apoe−/− mice. The authors showed that the four immunogens produced significant immunogenicity against native PCSK9 to day 120 after immunization of C57BL/6J and Apoe−/− mice. This resulted in significantly decreased plasma cholesterol levels in C57BL/6J mice, and to a lesser degree in Apoe−/− mice. The X-PCSK9-B1 treated mice had increased LDL receptor mRNA and protein levels at day 120 after treatment. Thus, this study provides a new, potentially promising approach that uses long-term immunotherapy for a treatment of hypercholesterolemia.

Is low total cholesterol levels associated with suicide attempt in depressive patients?

BackgroundPatients with major depressive disorder (MDD) have a high risk of suicide. Many pathophysiological factors involved in MDD and suicide such us a low cholesterol levels have been associated with MDD and increased vulnerability to suicide. In this study, we investigate the relation between lipid parameters and suicide risk in patients with MDD.MethodsPlasma levels of total cholesterol, triglycerides, and high-density lipoprotein cholesterol (HDL-c) and low-density lipoprotein cholesterol (LDL-c) were determined in 160 patients meeting the DSM-IV-TR criteria for MDD (110 patients without suicidal behavior and 52 suicidal attempters) and 151 healthy controls.ResultsA significant decrease in plasma cholesterol levels was observed in the group of suicidal depressive patients compared to those without suicidal behavior (p < 0.001). For the other lipid levels (triglycerides, HDL cholesterol, and LDL cholesterol), there were no significant differences between suicidal and non-suicidal patients.ConclusionsOur study showed a significant decrease in plasma cholesterol levels in suicidal patients. This result support the hypothesis of the association of low plasma cholesterol level and suicidal behavior in patients with major depressive disorder.

Cytotoxic activity of simvastatin in T47D breast cancer cell lines and its effect on cyclin D1 expression and apoptosis

Background : Statins (HMG-CoA Inhibitors) is a drug used for decreasing plasma cholesterol levels and used in therapy to prevent coronary artery disease. Research in animals and epidemiological studies showed that statin therapy can decrease risk against cancer associated with cholesterol. Based on that result then research of cytotoxic activity against simvastatin knowing cultur T47D breast cancer cells and his influence in decreasing expression of cyclin D1 and induction of apoptosis has been done. Research objectives : The aims of this research is to prove activities of simvastatin against T47D breast cancer cell culture, especially to examine cytotoxic activity, cyclin D1 expression, and simvastatin effect in apoptotic induction. Research method : The type of this research is quasi experiment with using posttest with non-equivalent control group design. Cytotoxicity test performed on T47D breast cancer cell cultures using MTT assay to determine IC 50 values after given simvastatine. Expression of cyclin D1 and apoptosis induction test detected using flow cytometry with antibody monoclonal anti-cyclin D1 and Annexin V-Pi, then analyzed by FACS-Calibur program. Results : Simvastatin has cytotoxic effect against T47D breast cancer cells with IC 50 values 25.25 µg/mL. Simvastatin with concentrations of 6.31; 12.62; 25.25 and 50.5 µg/mL was able to decrease the cyclin D1 expression. Furthermore, simvastatin can induce apoptosis with EC 50 values 26.96 µg/mL in T47D breast cancer cells. Conclusion : Simvastatin has cytotoxic activity of in T47D breast cancer cells and decreasing cyclin D1 expression and inducing apoptosis activity in T47D breast cancer cells. Keywords: simvastatin, cytotoxic, cyclin D1, apoptotic, T47D.

Dietary α-cyclodextrin reduces atherosclerosis and modifies gut flora in apolipoprotein E-deficient mice.

α-Cyclodextrin (α-CD), a cyclic polymer of glucose, has been shown to lower plasma cholesterol in animals and humans; however, its effect on atherosclerosis has not been previously described. apoE-knockout mice were fed either low-fat diet (LFD; 5.2% fat, w/w), or Western high fat diet (21.2% fat) containing either no additions (WD), 1.5% α-CD (WDA); 1.5% β-CD (WDB); or 1.5% oligofructose-enriched inulin (WDI). Although plasma lipids were similar after 11 weeks on the WD vs. WDA diets, aortic atherosclerotic lesions were 65% less in mice on WDA compared to WD (P < 0.05), and similar to mice fed the LFD. No effect on atherosclerosis was observed for the other WD supplemented diets. By RNA-seq analysis of 16S rRNA, addition of α-CD to the WD resulted in significantly decreased cecal bacterial counts in genera Clostridium and Turicibacterium, and significantly increased Dehalobacteriaceae. At family level, Comamonadaceae significantly increased and Peptostreptococcaceae showed a negative trend. Several of these bacterial count changes correlated negatively with % atherosclerotic lesion and were associated with increased cecum weight and decreased plasma cholesterol levels. Addition of α-CD to the diet of apoE-knockout mice decreases atherosclerosis and is associated with changes in the gut flora.

Adjuvant Therapy for Incremental Low-Density Lipoprotein Cholesterol Reduction With Ezetimibe

Atherosclerotic cardiovascular disease (CVD) remains the major cause of premature death in developing countries, even though CVD mortality has fallen considerably over recent decades in many countries. Low-density lipoprotein (LDL) cholesterol is an important cause of coronary heart disease. Ezetimibe is a nonstatin agent that was approved in 2003 as an adjunctive therapy in combination with statins because of its ability to decrease plasma cholesterol levels. However, during a period of 12 years, this drug has been used without evidence of any positive effect in terms of morbidity and mortality. The purpose of this review is to briefly discuss the data that seem pertinent regarding the role of ezetimibe in therapy. The precise role of ezetimibe relative to other lipid-lowering drugs is unclear. Similar reductions in LDL cholesterol can often be achieved simply by maximizing the dose of statins. Ezetimibe plus atorvastatin also produced a greater reduction in serum C-reactive protein than atorvastatin alone.

Assessment of a probiotic Containing Bacillus Subtilis on the Performance and Gut Health of Laying Japanese Quails (Coturnix Coturnix Japonica)

ABSTRACT The present study was carried out to determine the effects of the inclusion of a spore-forming probiotic (Bacillus subtilis) in laying Japanese quail diets as an alternative to growth-promoting antibiotics to help produce healthy eggs and meat. This experiment was conducted as a completely randomized design with three treatments (control, 0.05% bacitracin methylene disalicylate (BMD), or 0.1% Bacillus subtilis) of five replicates of 11 quails each. Feed intake and egg production were recorded daily on cage basis. Body weight was determined at the beginning and end of the trial (36 and 42 weeks). At the end of the experiment (42 weeks), antibodies against Newcastle disease and avian influenza, egg components, Haugh units, eggshell quality and breaking strength, blood parameters, cecal microbial population, villus length, and crypt depth were measured. The dietary inclusion of Bacillus subtilis and BMD significantly (p≤0.05) increased egg production and egg weight; however, eggshell thickness and breaking strength, Haugh units, and eggshell percentages were not affected. The dietary addition of both products significantly (p≤0.05) decreased plasma cholesterol levels and increased LDL levels, as well as antibody levels against Newcastle disease and avian influenza (p≤0.01). In birds fed Bacillus subtilis and BMD, crypt depth was reduced, but villus height and villus to crypt ratio were significantly increased (p≤0.001) compared with those fed the basal diet. Cecal coliforms, E. coli, and Salmonella counts were reduced (p≤0.01) in quails fed the diets containing Bacillus subtilis and BMD compared those quails fed the non-supplemented diet. The results of this study demonstrated that in absence of AGPs, the inclusion of a spore-forming probiotic partially improves the performance of laying quails.

Metformin promotes cholesterol efflux in macrophages by up-regulating FGF21 expression: a novel anti-atherosclerotic mechanism.

Metformin is widely used as a glucose-lowering agent in patients with type 2 diabetes (T2D). Recently, several studies have confirmed that metformin possessed multiple cardiovascular protective effects such as decreasing cardiovascular mortality, attenuating adverse cardiac and vascular remodeling and ameliorating atherosclerosis [1–3]. Hong et al. [4] in a multicenter, randomized, double-blind, placebo-controlled clinical trial found treatment with metformin for 3 years substantially reduced major cardiovascular events in a median follow-up of 5.0 years compared with glipizide in type 2 diabetes patients who had a history of coronary artery disease. Forouzandeh et al. [5] demonstrated metformin treatment significantly attenuated high-fat diet-induced atherosclerosis in apolipoprotein E-knockout (ApoE−/−) mice. These studies suggest metformin could ameliorate atherosclerosis, but the anti-atherosclerotic mechanism of metformin remains to be fully clarified. Previous studies reported that metformin could decrease plasma cholesterol levels in diabetic and non-diabetic patients beyond its glucose-lowering effect [6–9], and the lipid-lowering effect of metformin was also confirmed in a meta-analysis of randomized controlled trials (RCTs) [10]. Besides, it was found that metformin treatment could lower inflammation markers levels in patients at high risk of cardiovascular disease and restore impaired HDL-mediated cholesterol efflux from macrophages due to glycation [11, 12]. These effects may contribute to the anti-atherosclerotic properties of metformin. The deposition of excessive cholesterol in macrophages plays a key role in atherosclerotic plaque formation, thus removal of excess cholesterol from macrophages may attenuate and even regress the atherosclerosis [13]. It has been identified that removal of cholesterol from macrophages was mediated by several transmembrane transporters, including adenosine triphosphate binding cassette (ABC) transporters A1 and G1 [14]. Yvan-Charvet et al. [15] evidenced that combined deficiency of Abca1 and Abcg1 in macrophages severely damaged cholesterol efflux and accelerated atherosclerosis in low-density lipoprotein receptor-knockout (Ldlr-/-) mice. Bochem et al. [16] demonstrated that carriers of ABCA1 loss-of-function mutations presented with lower cholesterol efflux capacity and higher atherosclerotic burden compared with age and sex-matched controls. Conversely, increased expression of ABCA1 and ABCG1 was involved in redistribution of cholesterol from inner to outer leaflet of the plasma membrane, facilitating cholesterol efflux from cholesterol-loaded macrophages [17]. Overexpression of ABCA1 in macrophages increased cholesterol efflux by about 60 % (P = 0.0006) and reduced atherosclerotic plaques by about 68 % (P = 0.0008) in Ldlr-/- mice fed a Western-type diet for 12 weeks [18]. Thus, ABCA1- and ABCG1-driven cholesterol efflux in macrophages was a key regulator in anti-atherosclerosis. Fibroblast growth factor (FGF) 21, a member of FGF subfamily and mainly secreted by liver and adipose tissue, is a novel metabolic regulator with multiple cardioprotective efficacy [19]. It was found that FGF21 deficiency caused a marked exacerbation of atherosclerotic plaque formation in ApoE−/− mice [20]. Moreover, previous studies also demonstrated that FGF21 could activate ABCA1 and ABCG1 expression of macrophages and in turn promoted cholesterol efflux in macrophages [21, 22], suggesting up-regulation of FGF21 exerted function of reducing atherosclerotic plaques. Intriguingly, Nygaard et al. [23] found metformin significantly increased FGF21 expression in both rat and human hepatocytes. Another study showed metformin could increase serum FGF21 levels both in mice and human [24]. Thus, we speculate metformin stimulates ABCA1 and ABCG1 expression via up-regulation of FGF21. Taken together, we hypothesize metformin increases FGF21 expression, and subsequently promotes expression of ABCA1 and ABCG1 in macrophages, which promotes cholesterol efflux from macrophages and attenuated atherosclerotic plaques. Further exploring cardioprotective mechanism of metformin will be useful for insight into novel therapeutic targets.

Niemann-Pick C1-Like 1 (NPC1L1) Inhibition and Cardiovascular Diseases

Circulating levels of cholesterol are derived from either endogenous production or intestinal absorption of dietary and biliary cholesterol. Niemann-Pick C1-Like 1 (NPC1L1) is a transmembrane protein that plays a key role in the intestinal absorption of cholesterol by facilitating its uptake through vesicular endocytosis. NPC1L1 is the molecular target of ezetimibe which binds its extracellular loop and inhibits sterol absorption without affecting the absorption of other molecules. Ezetimibe significantly reduces plasma levels of total and low density lipoprotein cholesterol (LDL-C) as monotherapy or when added to statins, the association with a low dose of statin is of particular interest for patients experiencing statin-related side effects. The recent results of the IMPROVE-IT study, which evaluated the cardiovascular effect of ezetimibe added to simvastatin therapy in subjects who had had an acute coronary syndrome and with LDL-C levels within the recommended range, showed that a further LDL-C lowering reduced the incidence of cardiovascular events. To date, ezetimibe represents the only inhibitor of NPC1L1 available for clinical use, however, novel aminoß- lactam ezetimibe derivatives have been synthesized and their efficacy to inhibit NPC1L1 protein and decrease plasma cholesterol levels is under evaluation.

MicroRNA-185 modulates low density lipoprotein receptor expression as a key posttranscriptional regulator

ObjectiveLow-density lipoprotein receptor (LDLR) mediates endocytosis of LDL particles and is important in maintaining plasma cholesterol levels, thus its expression is under extensive regulation at multiple levels, including transcriptional and posttranscriptional regulation by transcription factors (TFs) and RNA-binding proteins (RBPs). Here, we identified microRNA-185 (miR-185) as a novel direct posttranscriptional regulator of LDLR and an indirect LDLR modulator through KSRP in hepatic cells. Methods and resultsUsing quantitative real-time PCR (qPCR), we detected the effect of predicted LDLR-targeting miRNAs and found that overexpression of miR-185 repressed LDLR expression and LDL uptake in HepG2 cells by 62.4 ± 6.0% (p = 7.0 × 10−5) and 32.5 ± 6.0% (p = 7.7 × 10−4) respectively, through directly targeting LDLR 3′UTR. Unexpectedly, the antisense inhibitor of miR-185 had similar repression effect on LDLR although it reduced the association of endogenous miR-185 with LDLR mRNA. Further experiments revealed that KH-type splicing regulatory protein (KSRP), one of the LDLR-destabilizing RBPs, is also a target of miR-185. KSRP silencing reversed the repression effects of miR-185-inhibitor on LDLR. Thus miR-185 regulates LDLR expression not only through directly targeting but also by a RBP-involved indirect pathway. Finally, the in vivo results showed that miR-185-inhibitor upregulated hepatic LDLR expression and correlated with a decrease in plasma cholesterol level and arterial plaque area in ApoE KO mice. ConclusionsThese findings reveal that miR-185 controls cholesterol homeostasis as a key posttranscriptional LDLR modulator in hepatic cells, providing novel insight into the regulatory mechanism for LDLR expression and the anti-atherosclerosis effect of miR-185-inhibitor.