Diet-induced Hypercholesterolemia Research Articles

ApoF knockdown increases cholesteryl ester transfer to LDL and impairs cholesterol clearance in fat-fed hamsters

Cholesteryl ester transfer protein (CETP) regulates intravascular lipoprotein metabolism. In vitro studies indicate that ApoF alters CETP function by inhibiting its activity with LDL. To explore in vivo the complexities driving ApoF's effects on CETP, we developed a siRNA-based hamster model of ApoF knockdown. In both male and female hamsters on chow- or fat-fed diets, we measured lipoprotein levels and composition, determined CETP-mediated transfer of cholesteryl esters (CEs) between lipoproteins, and quantified reverse cholesterol transport (RCT). We found that apoF knockdown in chow-fed hamsters had no effect on lipoprotein levels or composition, but these ApoF-deficient lipoproteins supported 50-100% higher LDL CETP activity in vitro. ApoF knockdown in fat-fed male hamsters created a phenotype in which endogenous CETP-mediated CE transfer from HDL to LDL increased up to 2-fold, LDL cholesterol increased 40%, HDL declined 25%, LDL and HDL lipid compositions were altered, and hepatic LDLR gene expression was decreased. Diet-induced hypercholesterolemia obscured this phenotype on occasion. In fat-fed female hamsters, ApoF knockdown caused similar but smaller changes in plasma CETP activity and LDL cholesterol. Notably, ApoF knockdown impaired HDL RCT in fat-fed hamsters but increased sterol excretion in chow-fed animals. These in vivo data validate in vitro findings that ApoF regulates lipid transfer to LDL. The consequences of ApoF knockdown on lipoproteins and sterol excretion depend on the underlying lipid status. By minimizing the transfer of HDL-derived CE to LDL, ApoF helps control LDL cholesterol levels when LDL clearance mechanisms are limiting.

Sepiolite Clay Attenuates the Development of Hypercholesterolemia and Obesity in Mice Fed a High-Fat High-Cholesterol Diet.

Obesity reduces the quality of life and life expectancy, whereas nonoperative interventions have shown poor results so far. Statins effectively combat hypercholesterolemia but are not well tolerated at high doses, raising the need for coprescription with cholesterol sorbents and/or absorption inhibitors. Montmorillonite (MMT) clay was found to attenuate hypercholesterolemia and obesity by reducing cholesterol and fat absorption. However, acicular clay-like sepiolite may offer better results due to its more substantial adsorption of nonpolar molecules. We herein aimed at (1) assessing in vitro the capacity of sepiolite to adsorb edible oil and cholesterol compared with that of MMT and (2) assessing in vivo the effect of continuous feeding on a high-fat high-cholesterol diet (HFD) (53.6% w/w fat and 0.2% cholesterol) supplemented with 5% (w/w) edible sepiolite, on diet-induced obesity rate, hypercholesterolemia, and hyperlipidemia. Fourier transform infrared spectroscopy showed in vitro that sepiolite adsorption of olive oil and cholesterol was five to eight times greater than that of MMT clay. Sepiolite supplementation to HFD fed to mature mice for 12.5 weeks resulted in lower total blood cholesterol and triacylglycerol levels and attenuated body weight gain, by reducing fat gain. Sepiolite supplementation did not affect energy intake but increased fecal extraction of sterols and lipids, without notable side effects. These results demonstrate that supplementing a HFD with sepiolite attenuates gastrointestinal absorption of dietary lipids and sterols, thus mitigating obesity, hyperlipidemia, and hypercholesterolemia. Further exploration of the efficacy, mechanism of action, and safety of sepiolite as a food supplement for combating the metabolic syndrome is needed.

Angiotensin II type 2 receptor mediates high fat diet-induced cardiomyocyte hypertrophy and hypercholesterolemia

Obesity is the major risk factor for several cardiovascular and metabolic disorders. Previous studies reported that deletion of Angiotensin II type 2 receptor (AT2R) protects against metabolic dysfunctions induced by high fat (HF) diet. However, the role of AT2R in obesity-induced cardiac hypertrophy remains unclear. Male AT2R knockout (AT2RKO) and wild type (AT2RWT) mice were fed with control or HF diet for 10 weeks. HF diet increased cardiac expression of AT2R in obese mice. Deletion of AT2R did not affect body weight gain, glucose intolerance and fat mass gain induced by HF feeding. However, loss of AT2R prevented HF diet-induced hypercholesterolemia and cardiac remodeling. Mechanistically, we found that pharmacological inhibition or knockdown of AT2R prevented leptin-induced cardiomyocyte hypertrophy in vitro. Collectively, our results suggest that AT2R is involved in obesity-induced cardiac hypertrophy.

Electronegative LDL from Rabbits Fed with Atherogenic Diet Is Highly Proinflammatory.

Electronegative low-density lipoprotein (LDL(-)) has been found in the plasma of familial hypercholesterolemia and acute myocardial infarction and has been implicated in atherosclerosis and cardiovascular disease. However, less is known about the involvement of LDL(-) in atherosclerosis-related inflammation. This study aims at investigating the inducibility of LDL(-) by atherogenic diet in rabbits and at exploring the proinflammatory potential of the diet-induced LDL(-) in macrophages. Rabbits were fed with an atherogenic diet; LDL was isolated from plasma by NaBr density gradient ultracentrifugation and was then resolved into nLDL and LDL(-) by anion-exchange chromatography. Isolated nLDL and LDL(-) were directly used or incubated with 10 μM CuSO4 for 24 h to produce copper- (Cu-) ox-nLDL and Cu-ox-LDL(-). The effects of these LDLs on inflammation were evaluated in THP-1-derived macrophages. Macrophages were treated with nLDL, LDL(-), and extensively oxidized LDL (ox-LDL), then the levels of interleukin- (IL-) 1β, IL-6, and tumor necrosis factor- (TNF-) α in a culture medium were determined by ELISA, and the levels of total and phosphorylated IκB, p65, p38, JNK, and ERK in cell lysates were determined by Western blotting. The LDL(-) induced significantly higher levels of IL-1β, IL-6, and TNF-α in the medium. The levels of phosphorylated/total IκB, p65, p38, JNK, and ERK were also upregulated by LDL(-). In contrast, nLDL, Cu-ox-nLDL, and Cu-ox-LDL(-) exhibited much less effect. Knockdown of lectin-type oxidized LDL receptor- (LOX-) 1 resulted in significant reduction in LDL(-)-induced IL-1β, IL-6, and TNF-α. In addition, these LDL(-) effects were also markedly attenuated by inhibition of NF-κB and ERK1/2. The data suggested that LDL(-) induced inflammation through LOX-1-, NF-κB-, and ERK1/2-dependent pathways. Taken together, our results show that rabbits fed with atherogenic diet produce a highly proinflammatory LDL(-) that is more potent in inducing inflammation than nLDL and extensively oxidize LDL in macrophages. The results thus provide a novel link between diet-induced hypercholesterolemia and inflammation.

Hypercholesterolemia affects cardiac function, infarct size and inflammation in APOE*3-Leiden mice following myocardial ischemia-reperfusion injury.

BackgroundHypercholesterolemia is a major risk factor for ischemic heart disease including acute myocardial infarction. However, long-term effects of hypercholesterolemia in a rodent myocardial ischemia-reperfusion injury model are unknown. Therefore, the effects of diet-induced hypercholesterolemia on cardiac function and remodeling were investigated up to eight weeks after myocardial ischemia-reperfusion (MI-R) injury which was induced in either normocholesterolemic (NC-MI) or hypercholesterolemic (HC-MI) APOE*3-Leiden mice.MethodsLeft ventricular (LV) dimensions were serially assessed using parasternal long-axis echocardiography followed by LV pressure-volume measurements. Subsequently, infarct size and the inflammatory response were analyzed by histology and fluorescence-activated cell sorting (FACS) analysis.ResultsIntrinsic LV function eight weeks after MI-R was significantly impaired in HC-MI compared to NC-MI mice as assessed by end-systolic pressure, dP/dtMAX, and -dP/dtMIN. Paradoxically, infarct size was significantly decreased in HC-MI compared to NC-MI mice, accompanied by an increased wall thickness. Hypercholesterolemia caused a pre-ischemic peripheral monocytosis, in particular of Ly-6Chi monocytes whereas accumulation of macrophages in the ischemic-reperfused myocardium of HC-MI mice was decreased.ConclusionDiet-induced hypercholesterolemia caused impaired LV function eight weeks after MI-R injury despite a reduced post-ischemic infarct size. This was preceded by a pre-ischemic peripheral monocytosis, while there was a suppressed accumulation of inflammatory cells in the ischemic-reperfused myocardium after eight weeks. This experimental model using hypercholesterolemic APOE*3-Leiden mice exposed to MI-R seems suitable to study novel cardioprotective therapies in a more clinically relevant animal model.

VEGF Therapy Shifts Macrophage Phenotype and Improves Renal Recovery in Chronic Kidney Disease

Chronic kidney disease (CKD) is universally associated with renal microvascular (MV) rarefaction and inflammation. We previously developed a fusion of rh‐vascular endothelial growth factor (VEGF) conjugated to an elastin like polypeptide (ELP) vector. We showed that ELP‐VEGF therapy is renoprotective in a model of unilateral renovascular disease (RVD). Here we test the hypothesis that ELP‐VEGF therapy in a novel model of CKD will recover renal function and MV rarefaction driven partly by modulation of renal macrophages to a pro‐angiogenic phenotype.CKD was induced in 10 pigs by bilateral RVD combined with diet‐induced hypercholesterolemia. After 6 weeks, pigs received a single intrarenal dose of ELP‐VEGF or placebo and were observed for 8 weeks. Renal blood flow (RBF) and glomerular filtration rate (GFR) were quantified using multidetector computed tomography before, and 4 and 8 weeks after ELP‐VEGF therapy. Blood and urine were collected to quantify serum creatinine and albuminuria. Pigs were then euthanized and renal MV density, VEGF expression, and inflammation were quantified. Renal macrophage infiltration and phenotype was determined by concurrent staining for CD68, indoleamine 2,3 dioxygenase (IDO), and mannose receptor c type 1 (MRC1) (indicating total, M1, and M2 macrophages respectively). Further staining was performed to colocalize MRC1 and VEGF. An additional 5 pigs served as normal controls.RBF and GFR were reduced in all pigs at 6 weeks. ELP‐VEGF therapy induced a progressive recovery of RBF and GFR, accompanied by improved MV density, VEGF expression, and reduced albuminuria (1.8 ± 0.3 mg/dL vs. 2.9 ± 0.9 mg/dL in untreated CKD, p < 0.05) and creatinine (160 ± 10 μmol/L vs. 202 ± 16 μmol/L in untreated CKD, p < 0.05). Heavy IDO+/MRC1− pro‐inflammatory M1 macrophage infiltration was observed in untreated CKD and was shifted to a IDO−/MRC1+ anti‐inflammatory M2 phenotype after ELP‐VEGF therapy. Furthermore, augmented co‐expression of VEGF was observed in the MRC1+ renal macrophages (Figure).The progressive recovery of renal function far outlasted the life of administered ELP‐VEGF, suggesting that this single dose activates an endogenous mechanism of renal repair to sustain long term improvement. Accumulation of VEGF expressing M2 macrophages in the renal parenchyma may account for the recovery of MV rarefaction and renal hemodynamics after ELP‐VEGF treatment in CKD. These results suggest that modulation of macrophages towards a highly angiogenic M2 phenotype may constitute a prominent mechanism of renal recovery after ELP‐VEGF therapy in CKD.Support or Funding InformationSupport: HL95638, HL51971, GM104357, HL121527 (NIH), and EIA18490005 and IPA34170267 (AHA).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Hepatocyte sortilin 1 knockout and treatment with a sortilin 1 inhibitor reduced plasma cholesterol in Western diet-fed mice

Sortilin 1 (Sort1) is a member of the Vps10p domain intracellular trafficking receptor family. Genetic variations of the SORT1 gene are strongly associated with plasma cholesterol levels in humans. Recent studies have linked Sort1 to regulation of cholesterol metabolism in hepatocytes and pro-inflammatory response in macrophages, but the tissue-specific roles of Sort1 in lipid metabolism have not been well defined. We developed Sort1 floxed mice and investigated the development of Western diet (WD)-induced steatosis, hepatic inflammatory response, and hyperlipidemia in hepatocyte Sort1 KO mice and myeloid cell Sort1 KO mice. Our findings suggest that hepatocyte Sort1 deficiency attenuated diet-induced hepatic steatosis and hypercholesterolemia in mice. In contrast, myeloid Sort1 deficiency did not reduce hepatic cytokine expression or plasma cholesterol levels, but exacerbated hepatic triglyceride accumulation in WD-fed mice. Finally, we showed that treating WD-fed mice with an orally bioavailable Sort1 inhibitor, AF38469, decreased plasma cholesterol and hepatic cytokine expression. AF38469 treatment did not affect diet-induced obesity or insulin resistance, but was associated with reduced hepatic VLDL secretion and higher hepatic cholesterol 7α-hydrolase expression in WD-fed mice. In conclusion, findings from this study suggest that Sort1 loss-of-function in hepatocytes contributes to lower plasma cholesterol, and pharmacological inhibition of Sort1 attenuates diet-induced hypercholesterolemia in mice.

PENGARUH EKSTRAK BUAH MENGKUDU (MORINDA CITRIFOLIA) TERHADAP KADAR KOLESTEROL TOTAL DARAH PADA TIKUS PUTIH (RATTUS NORVEGICUS) JANTANGALUR WISTARYANG DIBERI DIET TINGGI LEMAK


 
 
 Background: High cholesterol dietinduced hypercholesterolemia. Noni fruit extracthas flavonoids which are expected to reduceblood total cholesterol levels.This study aims to determine the effect of noni fruit extract (Morinda citrifolia) on total blood cholesterol levels in wistar strain male rats (Rattus norvegicus) given a high-fat diet. Method: Experimental study using post test only control group design. A total of 24 wistar strain male rats were divided into 3 groups: negative controlgroup given standard feed; positive control group of experimental animals who were given a high-fat diet; the experimental group treated with a high-fat diet for 14 days and given noni fruit extractat a dose of 200 mg / Kg BB. On the 29th day total blood cholesterol levels were measured for all groups of experimental animals. Results: The Mann Whitney UTest showed a significant increase in total blood cholesterol levels in the positive group of experimental animals given a high-fat diet (68.13 mg/dl) compared to the negative control group of experimental animals given standard feed (51.25 mg/dl). There was a significant decrease in total blood cholesterol levels in the experimental group treated with a high-fat diet and noni fruit extract (61mg/dl) compared to the average positive control group of experimental animals given a high-fat diet (68.13 mg/dl). Conclusion: Provision of a high-fat diet in wistar strain male ratscan significantly increase total blood cholesterol levels. The administration of noni fruit extract in wistar strain male ratscan significantly reduce total blood cholesterol levels
 
 

A Novel Contrast Agent Based on Magnetic Nanoparticles for Cholesterol Detection as Alzheimer\u2019s Disease Biomarker

BackgroundConsidering the high incidence of Alzheimer’s disease among the world population over the years, and the costs that the disease poses in sanitary and social terms to countries, it is necessary to develop non-invasive diagnostic tests that allow to detect early biomarkers of the disease. Within the early diagnosis methods, the development of contrast agents for magnetic resonance imaging becomes especially useful.Accumulating evidence suggests that cholesterol may play a role in the pathogenesis of Alzheimer’s disease since abnormal deposits of cholesterol surrounding senile plaques have been described in animal transgenic models and patients with Alzheimer’s disease. In vivo experiments have also shown that diet-induced hypercholesterolemia enhances intraneuronal accumulation of β-amyloid protein accompanied by microgliosis and accelerates β-amyloid deposition in brains.Presentation of the HypothesisIn the present study, we propose for the first time the synthesis of a new nanoconjugate composed of magnetic nanoparticles bound to an anti-cholesterol antibody, to detect the abnormal deposits of cholesterol observed in senile plaques in Alzheimer’s disease by magnetic resonance imaging. The nanoplatform could also reveal the decrease of cholesterol observed in neuronal plasmatic membranes associated with this pathology.Testing the HypothesisExperimental design to test the hypothesis will be done first in vitro and then in ex vivo and in vivo studies in a second stage.Implications of the HypothesisThe designed nanoplatform could therefore detect cholesterol deposits at the cerebral level. The detection of this biomarker in areas coinciding with senile plaque accumulations could provide early information on the onset and progression of Alzheimer’s disease.

Milk fermented with probiotic strains Lactobacillus rhamnosus MTCC: 5957 and Lactobacillus rhamnosus MTCC: 5897 ameliorates the diet-induced hypercholesterolemia in rats

The current study was intended to investigate the cholesterol-lowering potential of the two Lactobacillus rhamnosus probiotic strains, LR 5957 and LR 5897, isolated from ‘dahi’. Cholesterol-lowering ability of both strains was determined in in vitro conditions. For in vivo investigations, the Wistar rats were randomly assigned into five groups and treated with different diets: standard diet (SD), high-cholesterol diet (HCD), HCD with Milk, HCD with LR 5957–fermented milk, and HCD with LR 5897–fermented milk. After 3 months of feeding, different parameters of hypercholesterolemia were measured in blood, feces, liver, and kidney. Both the strains, LR 5957 and LR 5897, showed the ability to grow in the presence of cholesterol and eliminate the cholesterol under in vitro conditions. In vivo results indicate that consumption of probiotic-fermented milk has significantly reduced the HCD-induced body weight, hyperlipidemia, and hepatic lipids (total cholesterol and triacylglycerol). Further, increased cholesterol excretion in feces was also observed in probiotic-fed groups. The studied fermented milk also helped to maintain healthy liver and kidney by increasing the antioxidant activities and decreasing the lipid peroxidation. Consumption of probiotic-fermented milk also found to decrease the mRNA expression of the inflammatory markers TNF-α and IL-6 in the liver. Overall, our results indicate that the L. rhamnosus strains, LR 5957 and LR 5897, are two potential probiotic strains that can ameliorate the diet-induced hypercholesterolemia.

Egg phospholipids exert an inhibitory effect on intestinal cholesterol absorption in mice.

BACKGROUND/OBJECTIVESConsumption of cholesterol-rich foods, such as eggs, has a minimal effect on circulating cholesterol levels in healthy humans. To gain insight, we investigated whether phospholipids rich in eggs (EPL) interfere with intestinal cholesterol absorption in vivo.MATERIALS/METHODSTo investigate the acute effect of EPL on intestinal cholesterol absorption, male C57BL/6J mice were orally administered with 6, 11, or 19 mg of EPL for three days. We also tested the effect of chronic EPL consumption on cholesterol metabolism in the small intestine and the liver in mice with diet-induced hypercholesterolemia. Male C57BL/6J mice were fed a high fat/high cholesterol (HF/HC; 35% fat, 0.25% cholesterol, w/w) diet for 4 weeks to induce hypercholesterolemia, and subsequently the mice were either fed 0, 0.4 or 0.8% (w/w) of EPL for 6 weeks.RESULTSIntestinal cholesterol absorption was significantly decreased by the highest dose of acute EPL administration compared to control. Chronic EPL supplementation did not significantly alter intestinal cholesterol absorption nor plasma levels of total cholesterol and low-density lipoprotein cholesterol. In the small intestine and the liver, EPL supplementation minimally altered the expression of genes which regulate cellular cholesterol levels.CONCLUSIONAlthough chronic EPL consumption was not able to counteract hypercholesterolemia in HF/HC-fed mice, acute EPL administration decreased intestinal cholesterol absorption. This study provides in vivo evidence that acute administration of PLs in eggs prevent cholesterol absorption in the intestine, suggesting a mechanism for a minimal effect of egg consumption on circulating cholesterol levels.

Genetic depletion of Soat2 diminishes hepatic steatosis via genes regulating de novo lipogenesis and by GLUT2 protein in female mice

Depletion of the cholesterol esterifying enzyme acyl-Coenzyme A: cholesterol acyltransferase 2 (ACAT2, encoded by Soat2) protects mice from atherosclerosis, diet-induced hypercholesterolemia, and hepatic steatosis when fed high-cholesterol diet. The glucose transporter 2 (GLUT2) represents the main gate of glucose uptake by the liver. Lipid synthesis from glucose (de novo lipogenesis; DNL) plays a pivotal role in the development of hepatic steatosis. Inhibition of DNL is a successful approach to reverse hepatic steatosis, as shown by different studies in mice and humans. Here we aimed to investigate whether depletion of Soat2 per se can reduce hepatic steatosis, also in the presence of very low levels of cholesterol in the diet, and the underlying mechanisms. Female Soat2−/− and wild type mice were either fed high-fat or high-carbohydrate diet and both contained <0.05% (w/w) cholesterol. Analysis in serum, liver, muscles and adipose tissues were performed. We found Soat2−/− mice fed high-fat, low-cholesterol diet to have less hepatic steatosis, decreased expression of genes involved in DNL and lower hepatic GLUT2. Similar findings were found in Soat2-/- mice fed high-carbohydrate, low-cholesterol diet. ConclusionDepletion of Soat2 reduces hepatic steatosis independently of the presence of high levels of cholesterol in the diet. Our study provides a link between hepatic cholesterol esterification, DNL, and GLUT2.

Lactobacillus plantarum LRCC 5273 isolated from Kimchi ameliorates diet-induced hypercholesterolemia in C57BL/6 mice

This study was designed to select potent cholesterol-lowering probiotic strains on HepG2 cell and investigate the effect of selected strain, Lactobacillus plantarum LRCC 5273 and LRCC 5279 in hypercholesterolemic mice. In the results, LP5273 group showed significantly reduced total and LDL cholesterol compared to HCD group. In addition to significantly up-regulated hepatic mRNA expression of LXR-α and CYP7A1, intestinal LXR-α and ABCG5 were significantly up-regulated in LP5273 group. With activation of hepatic and intestinal LXR-α and its target genes, fecal cholesterol and bile acid excretion were increased in LP5273 fed mice. These results suggest that LP5273 ameliorates hypercholesterolemia in mice through the activation of hepatic and intestinal LXR-α, resulting in enhancement of fecal cholesterol and bile acids excretion in the small intestine. The results of present study suggest mechanistic evidences for hypocholesterolemic effects of L. plantarum spp., and may contribute to future researches for prevention of hypercholesterolemia and cardiovascular disease.

LJ-1888, a selective antagonist for the A3 adenosine receptor, ameliorates the development of atherosclerosis and hypercholesterolemia in apolipoprotein E knock-out mice

Cardiovascular diseases arising from atherosclerosis are the leading causes of mortality and morbidity worldwide. Lipid-lowering agents have been developed in order to treat hypercholesterolemia, a major risk factor for atherosclerosis. However, the prevalence of cardiovascular diseases is increasing, indicating a need to identify novel therapeutic targets and develop new treatment agents. Adenosine receptors (ARs) are emerging as therapeutic targets in asthma, rheumatoid arthritis, cancer, ischemia, and inflammatory diseases. This study assessed whether LJ-1888, a selective antagonist for A3 AR, can inhibit the development of atherosclerosis in apolipoprotein E knock-out (ApoE−/−) mice who are fed a western diet. Plaque formation was significantly lower in ApoE−/− mice administered LJ-1888 than in mice not administered LJ-1888, without any associated liver damage. LJ-1888 treatment of ApoE−/− mice prevented western diet-induced hypercholesterolemia by markedly reducing low-density lipoprotein cholesterol levels and significantly increasing high-density lipoprotein cholesterol concentrations. Reduced hypercholesterolemia in ApoE−/− mice administered LJ-1888 was associated with the enhanced expression of genes involved in bile acid biosynthesis. These findings indicate that LJ-1888, a selective antagonist for A3 AR, may be a novel candidate for the treatment of atherosclerosis and hypercholesterolemia.

Cystathionine-\u03b3-lyase expression is associated with mitochondrial respiration during sepsis-induced acute kidney injury in swine with atherosclerosis

BackgroundSepsis is associated with disturbed glucose metabolism and reduced mitochondrial activity and biogenesis, ultimately leading to multiple organ dysfunction, e.g., acute kidney injury (AKI). Cystathionine-γ-lyase (CSE), the major cardiovascular source of endogenous H2S release, is implicated in the regulation of glucose metabolism and mitochondrial activity through a PGC1α-dependent mechanism, and critical for kidney function. Atherosclerosis is associated with mitochondrial dysfunction and reduced CSE expression. Thus, the aim of this post hoc study was to test the hypothesis whether there is an interplay between CSE expression and kidney dysfunction, mitochondrial activity, and oxidative/nitrosative stress in porcine septic AKI with underlying coronary artery disease.MethodsThis study is a post hoc analysis of material from anesthetized and instrumented swine with a high fat diet-induced hypercholesterolemia and atherosclerosis undergoing faecal peritonitis-induced septic shock or sham procedure and intensive care (comprising fluid resuscitation and continuous i.v. noradrenaline (NoA) infusion) for 24 h. Glucose metabolism was quantified from blood 13C6-glucose and expiratory 13CO2/12CO2 isotope enrichment during 13C6-glucose infusion. Mitochondrial activity was determined by high-resolution respirometry. CSE and PGC1α expression, as well as nitrotyrosine formation and albumin extravasation, were quantified by immunohistochemistry of formalin-fixed kidney paraffin sections.ResultsSepsis was associated with lactic acidosis (p = 0.004) and AKI (50% fall of creatinine clearance (CrCl), p = 0.019). While both whole-body glucose production (p = 0.004) and oxidation (p = 0.006) were increased, kidney tissue mitochondrial respiration was reduced (p = 0.028), coinciding with decreased CSE (p = 0.003) and PGC1α (p = 0.003) expression. Albumin extravasation (p = 0.011) and nitrotyrosine formation (p = 0.008) were increased in septic kidneys.ConclusionsSepsis-induced AKI is associated with disturbed mitochondrial respiration and biogenesis, which may be aggravated by oxidative and nitrosative stress. Our results confirm previous data in murine septic shock and porcine hemorrhage and resuscitation on the crucial role of CSE for barrier integrity and kidney function.

Cholesterol burden in the liver induces mitochondrial dynamic changes and resistance to apoptosis

Non-alcoholic fatty liver disease (NAFLD) encompasses a broad spectrum of histopathological changes ranging from non-inflammatory intracellular fat deposition to non-alcoholic steatohepatitis (NASH), which may progress into hepatic fibrosis, cirrhosis, or hepatocellular carcinoma. Recent data suggest that impaired hepatic cholesterol homeostasis and its accumulation are relevant to the pathogenesis of NAFLD/NASH. Despite a vital physiological function of cholesterol, mitochondrial dysfunction is an important consequence of dietary-induced hypercholesterolemia and was, subsequently, linked to many pathophysiological conditions. The aim in the current study was to evaluate the morphological and molecular changes of cholesterol overload in mouse liver and particularly, in mitochondria, induced by a high-cholesterol (HC) diet for one month. Histopathological studies revealed microvesicular hepatic steatosis and significantly elevated levels of liver cholesterol and triglycerides leading to impaired liver synthesis. Further, high levels of oxidative stress could be determined in liver tissue as well as primary hepatocyte culture. Transcriptomic changes induced by the HC diet involved disruption in key pathways related to cell death and oxidative stress as well as upregulation of genes related to glutathione homeostasis. Impaired liver function could be associated with a decrease in mitochondrial membrane potential and ATP content and significant alterations in mitochondrial dynamics. We demonstrate that cholesterol overload in the liver leads to mitochondrial changes which may render damaged hepatocytes proliferative and resistant to cell death whereby perpetuating liver damage.

Boiled, sprouted, and raw cowpea-incorporated diets modulate high-fat diet-induced hypercholesterolemia in rats.

This study was carried out to investigate the effect of processed (boiled and sprouted) cowpea‐incorporated experimental diets on serum cholesterol and serum antioxidant capacity in high‐fat diet (HFD)‐fed Wistar rats. Seven weeks old male Wistar rats were fed 20% fat as a control (CD), for comparison with 20% fat‐enriched diets containing 20% whole raw cowpea diets (Bombay Raw Diet; BRD and MI35 Raw Diet; MRD), boiled cowpea diets (Bombay Boiled Diet; BBD and MI35 Boiled Diet; MBD) and sprouted cowpea diet (Bombay Sprouted Diet; BSD) for 6 weeks. The increase in serum total cholesterol as a result of high‐fat diet was significantly countered by boiled and raw cowpea‐incorporated diet‐fed rats. Increased serum non‐HDL‐C level caused by HFD was significantly (p < 0.05) countered by raw, boiled, and sprouted cowpeas, while HDL–C was increased by raw MI and boiled Bombay incorporated diets. Boiling has improved the hypocholesterolemic ability of Bombay cowpea and BBD has significantly (p < 0.05) modulated serum HDL‐C level and liver weight in rats. These findings were supported significantly high soluble fiber content in processed cowpea powder than that in raw cowpea powder. The decrease in serum antioxidant activity as a result of HFD was significantly countered by BRD. Processing has reduced the antioxidant activity in cowpeas and serum antioxidant activity in rats. Cecal lactobacilli population was significantly high in all cowpea diet‐fed groups compared to control. Modulated serum cholesterol level in cowpea diet‐fed rats was accompanied by dietary fiber composition, antioxidant activity in cowpeas and fecal weight, cecal weight and cecal lactobacilli population in rats compared to control. Both processed and raw cowpea‐incorporated diets have modulated HFD‐induced hypercholesterolemia by modulating serum antioxidative capacity, cholesterol metabolism, and cecal fermentation.

EP4 emerges as a novel regulator of bile acid synthesis and its activation protects against hypercholesterolemia

Prostaglandin E receptor subtype 4 (EP4) knockout mice develops spontaneous hypercholesterolemia but the detailed mechanisms by which EP4 affects cholesterol homeostasis remains unexplored. We sought to determine the cause of hypercholesterolemia in EP4 knockout mice, focusing on the role of EP4 in regulating the synthesis and elimination of cholesterol. Deficiency of EP4 significantly decreased total bile acid levels in the liver by 26.2% and the fecal bile acid content by 27.6% as compared to wild type littermates, indicating that the absence of EP4 decreased hepatic bile acid synthesis and their subsequent excretion in stools. EP4 deficiency negatively regulate bile acid synthesis through repression of phosphorylated extracellular signal-regulated kinase 1/2 (ERK)-mediated cholesterol 7α-hydroxylase (CYP7A1) expression and that the hypercholesterolemia in EP4 knockout mice is due to a defect in cholesterol conversion into bile acids. Deficiency of EP4 also increased de novo cholesterol synthesis and altered cholesterol fluxes in and out of the liver. Treating high fat diet-challenged mice with the pharmacological EP4 agonist, CAY10580 (200 μg/kg body weight/day i.p) for three weeks effectively prevented diet-induced hypercholesterolemia, enhanced endogenous bile acid synthesis and their fecal excretion. In summary, EP4 plays a critical role in maintaining cholesterol homeostasis by regulating the synthesis and elimination of bile acids. Activation of EP4 serves as an effective novel strategy to promote cholesterol disposal in the forms of bile acids in order to lower plasma cholesterol levels.

A LIMA1 variant promotes low plasma LDL cholesterol and decreases intestinal cholesterol absorption.

A high concentration of low-density lipoprotein cholesterol (LDL-C) is a major risk factor for cardiovascular disease. Although LDL-C levels vary among humans and are heritable, the genetic factors affecting LDL-C are not fully characterized. We identified a rare frameshift variant in the LIMA1 (also known as EPLIN or SREBP3) gene from a Chinese family of Kazakh ethnicity with inherited low LDL-C and reduced cholesterol absorption. In a mouse model, LIMA1 was mainly expressed in the small intestine and localized on the brush border membrane. LIMA1 bridged NPC1L1, an essential protein for cholesterol absorption, to a transportation complex containing myosin Vb and facilitated cholesterol uptake. Similar to the human phenotype, Lima1-deficient mice displayed reduced cholesterol absorption and were resistant to diet-induced hypercholesterolemia. Through our study of both mice and humans, we identify LIMA1 as a key protein regulating intestinal cholesterol absorption.

Effects of bound phenolic from defatted Moringa oleifera seed flour on diet-induced hypercholesterolemic mice

The effect of bound phenolic and catechins extracted from defatted Moringa oleifera seed (DMSF) flour on diet-induced hypercholesterolemia was evaluated in this study. The animals (C57BL6 mice) were divided into four groups: group one received AIN 93M diet (control) group two received high-fat cholesterol diet (HFCD), three and four received HFCD along with bound phenolic and catechins, respectively, through oral administration at the dose of 25 mg/kg body weight daily for 8 weeks. Blood and tissue analysis showed that bound phenolic and catechins were able to reduce plasma and liver cholesterol significantly (p < .05). And these extracts were also able to reduce stress enzymes and molecules level in liver. The bound phenolic and catechins extracts from DMSF were able to increase plasma HDL level and lower atherogenic index in the treated groups. The data suggests that the combination of HFCD and bound phenolic or catechins extracted from DMSF as a source of antioxidants was beneficial. Practical applications In the present study the bound phenolic and catechins extracted from DMSF was studied for its effect on reducing cholesterol. DMSF is a processing waste left over after extraction of oil, hence prove to be cost-effective. In this study catechins (catechin and epicatechin) as well as combination of catechin-rich bound phenolic containing gallic acid, protocatechuic acid, ferulic acid, and catechin gallate were studied for its hypocholesterolemic effect. The results revealed that the combination of bound phenolic or catechins were comparably beneficial in reducing cholesterol and atherogenic index in diet induced mice model, which is the critical risk factor for atherosclerosis.