Increased Plasma Cholesterol Levels Research Articles

Liver Pyruvate Kinase Promotes NAFLD/NASH in Both Mice and Humans in a Sex-Specific Manner.

Background & AimsThe etiology of nonalcoholic fatty liver disease (NAFLD) is poorly understood, with males and certain populations exhibiting markedly increased susceptibility. Using a systems genetics approach involving multi-omic analysis of ∼100 diverse inbred strains of mice, we recently identified several candidate genes driving NAFLD. We investigated the role of one of these, liver pyruvate kinase (L-PK or Pklr), in NAFLD by using patient samples and mouse models.MethodsWe examined L-PK expression in mice of both sexes and in a cohort of bariatric surgery patients. We used liver-specific loss- and gain-of-function strategies in independent animal models of diet-induced steatosis and fibrosis. After treatment, we measured several metabolic phenotypes including obesity, insulin resistance, dyslipidemia, liver steatosis, and fibrosis. Liver tissues were used for gene expression and immunoblotting, and liver mitochondria bioenergetics was characterized.ResultsIn both mice and humans, L-PK expression is up-regulated in males via testosterone and is strongly associated with NAFLD severity. In a steatosis model, L-PK silencing in male mice improved glucose tolerance, insulin sensitivity, and lactate/pyruvate tolerance compared with controls. Furthermore, these animals had reduced plasma cholesterol levels and intrahepatic triglyceride accumulation. Conversely, L-PK overexpression in male mice resulted in augmented disease phenotypes. In contrast, female mice overexpressing L-PK were unaffected. Mechanistically, L-PK altered mitochondrial pyruvate flux and its incorporation into citrate, and this, in turn, increased liver triglycerides via up-regulated de novo lipogenesis and increased PNPLA3 levels accompanied by mitochondrial dysfunction. Also, L-PK increased plasma cholesterol levels via increased PCSK9 levels. On the other hand, L-PK silencing reduced de novo lipogenesis and PNPLA3 and PCSK9 levels and improved mitochondrial function. Finally, in fibrosis model, we demonstrate that L-PK silencing in male mice reduced both liver steatosis and fibrosis, accompanied by reduced de novo lipogenesis and improved mitochondrial function.ConclusionsL-PK acts in a male-specific manner in the development of liver steatosis and fibrosis. Because NAFLD/nonalcoholic steatohepatitis exhibit sexual dimorphism, our results have important implications for the development of personalized therapeutics.

Global DNA methylation in rats´ liver is not affected by hypercholesterolemic diet.

Increased plasma cholesterol levels are listed between the major atherosclerosis risk factors. The final plasma cholesterol levels result from the interplay between the genetic and environmental (diet, physical activity) factors. Little is known, how dietary factor influence epigenetics. We have analyzed, if an over-generation feeding of rat with cholesterol influences total liver-DNA methylation, and if total liver-DNA methylation differ between the different rat strains (Prague hereditary hypercholesterolemic rats, Prague hereditary hypertriglyceridemic rats and Wistar Kyoto rats). The animals were feed with high fat (additional 5 % over normal capacity) high cholesterol (2 %) diet for 14 days. DNA methylation in the liver tissue in different generations was analyzed using the liquid chromatography coupled with tandem mass spectrometry. We have not observed any significant changes in total liver-DNA methylation over the 9 generations of animals feed by fat/cholesterol enriched diet. Additionally, there were no differences in DNA methylation between different rat strains. In animal model, the dietary changes (hypercholesterolemic diet) not significantly influence the total DNA methylation status within the liver.

Etiology of disrupted cholesterol metabolism in the liver of young rats submitted to obesogenic diets

The purpose of the study was to test the hypothesis that a short period (2 weeks) of a high fat (HFD) and a western (WD) diet leading to an increase in liver fat accumulation will disrupt key markers of liver cholesterol metabolism mainly targeting the LDL‐receptor (LDL‐R) pathway. Rats were submitted to either a standard (SD), HFD (60%) or a WD (40% fat + 35% sucrose) diet for 2 and 6 weeks. Body weight gain and body fat values were higher (p < 0.01) in rats fed the HFD and WD for 6 weeks although food intakes in kcal/d were not different for all groups throughout the experimental period. Liver fat accumulation was significantly (P < 0.01) higher in HFD and WD rats as compared to the SD diet for both feeding durations. On the other hand, liver fat accumulation was higher in WD rats (P < 0.05) than HFD animals after two weeks of treatment. In addition, WD animals displayed the highest plasma cholesterol levels. After 2 and 6 weeks of treatment, hepatic gene expression of LDL‐R, Pcsk9 and SREBP‐2 was lower (p < 0.01) in WD animals than in HFD and SD rats. In addition, mRNA levels of Lrp1 and Acat2 were lower (p < 0.01) in WD rats as compared to those fed with SD. Gene expression of HMGCoA‐r, the main enzyme involved in the regulation of cholesterol synthesis, was lower in HFD (2 weeks) and even more so in rats fed the WD diet (2 and 6 weeks). The WD was associated with a higher (p < 0.01) gene expression of markers involved in the mediation of de novo lipogenesis (ACC and ChREBP). It is concluded that a short‐term WD promptly increased fat accumulation while disrupting cholesterol metabolism in the liver. The present results provide new insights on the mechanisms through which westernized diets rapidly promote increases in plasma cholesterol levels.Support or Funding InformationNSERC, FRQS, CFI

Invariant Natural Killer T-Cells and Total CD1d Restricted Cells Differentially Influence Lipid Metabolism and Atherosclerosis in Low Density Receptor Deficient Mice.

Natural killer T (NKT) cells are a distinct subset of lymphocytes that bridge the innate and adaptive immune response and can be divided into type I invariant NKT cells (iNKT) and type II NKT cells. The objective of this study is to examine the effects of NKT cell on lipid metabolism and the initiation and progression of atherosclerosis in LDL receptor deficient (LDLR−/−) mice. Mice were fed an atherogenic diet for 4 or 8 weeks and plasma lipids, lipoproteins, and atherosclerosis were measured. The selective absence of iNKT cells in Jα18−/−LDLR−/− mice led to an increase in plasma cholesterol levels in female mice. Transgenic Vα14tg/LDLR−/− mice with elevated numbers of iNKT cells had increased late atherosclerosis of the innominate artery, though absence of either iNKT cells or all NKT cells and other CD1d expressing cells had varying effects on atherosclerotic lesion burden in the ascending aortic arch and aortic root. These studies not only highlight the potential modulatory role played by NKT cells in atherosclerosis and lipid metabolism, but also raise the possibility that divergent roles may be played by iNKT and CD1d restricted cells such as type II NKT cells or other CD1d expressing cells.

Effects of replacement of para-grass with oil palm compounds on body weight, food intake, nutrient digestibility, rumen functions and blood parameters in goats.

ObjectiveThe aim of the present study was to investigate the beneficial effects of dietary supplementation with oil palm frond (leaf) (OPF) with and without oil palm meal (OPM) on nutrient intake and digestibility, ruminal fermentation and growth performance in goats.MethodsSix female crossbred goats were fed for 28 days of 3 diet treatments; 100% para-grass (T1); 50% para-grass + 50% OPF (T2), and 30% para-grass + 50% OPF + 20% OPM (T3). Body weight, rectal temperature, respiratory rate, and urine volume, food intake, dry matter intake and water intake were measured daily. Nutrient digestibility was determined from five consecutive days of last week in each diet. Ruminal fluid, urine and blood were collected at the end for determination of rumen protozoa and volatile fatty acid contents, urinary allantoin excretion, blood cell count and chemistry profiles.ResultsGoats fed T2 and T3 showed higher dry matter and nutrients intakes while protein digestibility was suppressed compared with those for T1. Crude fat digestibility declined in T2 but maintained after adding the OPM (T3). High fat intake by giving OPF and OPM corresponded to a higher ruminal acetate/propionate ratio (C2/C3) and serum cholesterol level. An increased urinary allantoin/creatinine ratio was found in T2 and T3 compared with T1, implying an increased number of ruminal microbes.ConclusionIncreased dry matter intake in T2 and T3 suggested that oil palm by-products are partly useful as a replacement for para-grass in goats. Replacement with the by-products increased plasma cholesterol level, which suggested that these products are a useful energy source. Changes in rumen parameters suggested an increased microbial number and activity suitable for acetate production. However, the limited digestibility of protein implies that addition of high protein feeds may be recommended to increase body weight gain of goats.

IFN-α-2b treatment protects against diet-induced obesity and alleviates non-alcoholic fatty liver disease in mice

IFN-α is used for inflammatory purposes, and obesity and NAFLD are strongly correlated with inflammatory processes. We wondered whether IFN-α-2b can attenuate obesity development and its associated NAFLD in mice fed high fat diet (HFD) for 10 weeks. IFN-α-2b had a robust effect on body weight loss associated with NAFLD amelioration by decreasing hepatic inflammation. IFN-α-2b-treated mice showed increased plasma cholesterol levels together with decreased hepatic cholesterol, both on chow and HF diets. Interestingly, mice on IFN-α-2b treatment secreted smaller VLDL particles highly enriched in cholesterol. Mechanistically, we found that IFN-α-2b antiobesity effects were related to increased fatty acid oxidation; and its effects on cholesterol metabolism were due to both a decrease in the master cholesterogenic transcription factor SREBP-2 and in the rate limiting enzyme in cholesterol synthesis, HMGCR. To our knowledge, this is the first report showing the effects of IFN-α-2b on the prevention of the development of HFD-induced body weight gain and dyslipidemia through a mechanism that involves fatty acid oxidation and cholesterol decrease. These studies comprise necessary steps for understanding the amelioration of obesity and NAFLD. Results shed some light into the mechanism of action of natural cytokines, and their effects on ameliorating obesity and its related diseases.

Two weeks of high-fat feeding disturb lipid and cholesterol molecular markers.

Metabolic disorders are often associated with liver steatosis and increased plasma cholesterol levels. However, the link between excessive lipid accumulation and impairments in cholesterol metabolism remains uninvestigated in the liver. Short term of high-fat diet (HFD) was previously shown to promote excessive lipid accumulation prior to the development of metabolic disorders. The present study intended to characterize how increases in liver fat alter the expression of several key regulators of hepatic cholesterol metabolism in response to a short-term HFD. Wistar rats were randomly submitted either to HFD (n=8) or a regular chow diet (n=8) for 14days. Increases in triglycerides were highly significant (P<0.01) in the liver but marginal in the plasma of HFD rats. In contrast, the HFD resulted in higher (P<0.01) cholesterol levels in plasma but not in liver samples. Gene expression of key markers involved in cholesterol uptake (LDL particles) including low-density lipoprotein receptor-related protein-1 (LRP-1) and protein convertase subtilisin/kexin type 9 (PCSK9) along with ATP-binding cassette, superfamily G, member 5 (ABCG5) involved in cholesterol exportation via bile ducts was found to be higher (P<0.05) in response to the HFD. In contrast, expression of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), involved in cholesterol synthesis, was downregulated in the liver. The data support the concept that excessive accumulation of lipids promptly alters the expression of key genes regulating cholesterol metabolism in the liver. On a clinical point of view, this indicates that increases in plasma cholesterol occur after a short-term HFD.

Apolipoprotein E deficiency accelerates atherosclerosis development in miniature pigs.

ABSTRACTMiniature pigs have advantages over rodents in modeling atherosclerosis because their cardiovascular system and physiology are similar to that of humans. Apolipoprotein E (ApoE) deficiency has long been implicated in cardiovascular disease in humans. To establish an improved large animal model of familial hypercholesterolemia and atherosclerosis, the clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 system (CRISPR/Cas9) was used to disrupt the ApoE gene in Bama miniature pigs. Biallelic-modified ApoE pigs with in-frame mutations (ApoEm/m) and frameshift mutations (ApoE−/−) were simultaneously produced. ApoE−/− pigs exhibited moderately increased plasma cholesterol levels when fed with a regular chow diet, but displayed severe hypercholesterolemia and spontaneously developed human-like atherosclerotic lesions in the aorta and coronary arteries after feeding on a high-fat and high-cholesterol (HFHC) diet for 6 months. Thus, these ApoE−/− pigs could be valuable large animal models for providing further insight into translational studies of atherosclerosis.

PL-006 Expression of molecular markers of hepatic cholesterol metabolism are altered by a short-term high-fat diet

Objective Metabolic disorders are often associated with liver steatosis and increased plasma cholesterol levels. However, the link between excessive lipid accumulation and impairments in cholesterol metabolism remains uninvestigated in the liver. Hence, a short treatment with a high-fat diet (HFD) was previously shown to promote excessive lipid accumulation in liver prior to the development of metabolic disorders. The present study intended to characterize how increases in liver fat alter the expression of several key regulators of hepatic cholesterol metabolism in response to a short-term HFD.&#x0D; Methods Young Wistar rats were randomly submitted either to HFD (n = 8) or a regular chow diet (RCD; n = 8) for 14 days.Liver tissue and blood were sampled .&#x0D; Results Increases in triglycerides were highly significant (P&lt; 0.01) in liver but marginal in plasma of HFD rats. In contrast, the HFD resulted in higher (P&lt; 0.01) cholesterol levels in plasma but not in liver samples. Gene expression of key markers involved in cholesterol uptake (LDL particles) including low density lipoprotein receptor-related protein-1 (LRP-1) and protein convertase subtilisin/kexin type 9 (PCSK9) along with ATP-binding cassette, superfamily G, member 5 (ABCG5) involved in cholesterol exportation viabile ducts were found to be higher (P&lt; 0.05) in response to the HFD. In contrast, expression of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), involved in cholesterol synthesis was down-regulated in liver&#x0D; Conclusions The data support the concept that excessive accumulation of lipids promptly alters the expression of key genes regulating cholesterol metabolism in liver. On a clinical point of view, this indicates that increases in plasma cholesterol occur after a short-term high fat diet.

Absence of adverse effects following administration of piperine in the diet of Sprague-Dawley rats for 90 days

Piperine (E,E-) is a naturally occurring pungent and spicy constituent of black pepperand is also used as an added flavoring ingredient to foods and beverages. Piperine has been determined safe under conditions of intended use as a flavoring substance by regulatory and scientific expert bodies. While concurring with the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and Flavor and Extract Manufacturers Association (FEMA) Expert Panel on the safety of piperine, the European Food Safety Authority (EFSA) requested additional toxicological data. The results of a 90-day GLPcompliant dietary study, conducted in Sprague-Dawley rats at target doses of 0, 5, 15, or 50 mg/kg bw/day, to respond to this request are presented herein. No adverse effects were found attributable to ingestion of piperine. Statistically significant changes in food consumption, body weight gain, and plasma cholesterol levels were not considered adverse as discussed in this paper. Therefore, the oral no-observed-adverse-effect level (NOAEL) was determined to be the highest dose tested of 50 mg/kg bw/day. EFSA derived a lower NOAEL of 5 mg/kg bw/day based on increased plasma cholesterol levels which still affords an adequate margin of safety of over 48,000 and concluded that piperine is not of safety concern.

Loss of the Liver X Receptors Disrupts the Balance of Hematopoietic Populations, With Detrimental Effects on Endothelial Progenitor Cells.

BackgroundThe liver X receptors (LXRs; α/β) are nuclear receptors known to regulate cholesterol homeostasis and the production of select hematopoietic populations. The objective of this study was to determine the importance of LXRs and a high‐fat high‐cholesterol diet on global hematopoiesis, with special emphasis on endothelial progenitor cells (EPCs), a vasoreparative cell type that is derived from bone marrow hematopoietic stem cells.Methods and ResultsWild‐type and LXR double‐knockout (Lxrαβ−/−) mice were fed a Western diet (WD) to increase plasma cholesterol levels. In WD‐fed Lxrαβ−/− mice, flow cytometry and complete blood cell counts revealed that hematopoietic stem cells, a myeloid progenitor, and mature circulating myeloid cells were increased; EPC numbers were significantly decreased. Hematopoietic stem cells from WD‐fed Lxrαβ−/− mice showed increased cholesterol content, along with increased myeloid colony formation compared with chow‐fed mice. In contrast, EPCs from WD‐fed Lxrαβ−/− mice also demonstrated increased cellular cholesterol content that was associated with greater expression of the endothelial lineage markers Cd144 and Vegfr2, suggesting accelerated differentiation of the EPCs. Treatment of human umbilical vein endothelial cells with conditioned medium collected from these EPCs increased THP‐1 monocyte adhesion. Increased monocyte adhesion to conditioned medium–treated endothelial cells was recapitulated with conditioned medium from Lxrαβ−/− EPCs treated with cholesterol ex vivo, suggesting cholesterol is the main component of the WD inducing EPC dysfunction.Conclusions LXRs are crucial for maintaining the balance of hematopoietic cells in a hypercholesterolemic environment and for mitigating the negative effects of cholesterol on EPC differentiation/secretome changes that promote monocyte‐endothelial adhesion.

Abstract 600: Hepatic (Pro)renin Receptor Inhibition Decreases Plasma Cholesterol and Triglyceride Levels but Does Not Ameliorate Atherosclerosis in LDLR -/- Mice

Rationale: Cardiovascular diseases (CVD) are the leading cause of death worldwide. Atherosclerosis, dyslipidemia, hypertension, obesity and diabetes are major risk factors for CVD. Elevated plasma cholesterol, especially low-density lipoprotein cholesterol (LDL-c), accelerates atherosclerosis development by inducing lipid accumulation in the vascular wall, foam cell formation and chronic inflammation. Hypertriglyceridemia has also been identified as a risk factor for CVD. Recently, we have identified the (pro)renin receptor [(P)RR], a signaling receptor for renin/prorenin, as a key regulator of lipid metabolism. Inhibiting the (P)RR receptor prevented diet-induced obesity and dyslipidemia in C57BL/6J mice, suggesting that (P)RR inhibition might be used to treat atherosclerosis. Therefore, in the current study, we aimed to explore whether inhibiting the hepatic (P)RR in LDLR -/- mice could reduce plasma lipid levels and attenuate atherosclerosis. Methods and Results: Eight week-old male LDLR -/- mice were injected with GalNAc-modified (liver-specific) antisense oligos against the (P)RR weekly, and fed a high-fat diet (HFD) for 16 weeks. Inhibiting the hepatic (P)RR prevented HFD-induced obesity in LDLR -/- mice, similar to our previous observation in C57BL/6J mice. Moreover, (P)RR inhibition decreased the HFD-induced increase in plasma cholesterol levels by almost 50%. FPLC analysis revealed that the VLDL fraction but not the IDL/LDL fraction was reduced by (P)RR inhibition. Plasma triglyceride levels decreased from 1249 ± 136 to 207 ± 32 mg/dL. Remarkably, despite these changes, (P)RR inhibition did not reduce atherosclerotic lesion areas in the aortic root, and even increased plaque size in the entire aorta. Conclusion: Hepatic (P)RR inhibition reduces obesity and plasma cholesterol in HFD-fed LDLR -/- mice, yet failed to ameliorate atherosclerosis. The latter most likely relates to the lack of effect of (P)RR inhibition on LDL-c, and implies that only LDL-c, and not triglycerides contribute to atherosclerosis progression.

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.

PCSK9 at the crossroad of cholesterol metabolism and immune function during infections.

Sepsis, a complex and dynamic syndrome resulting from microbial invasion and immune system dysregulation, is associated with an increased mortality, reaching up to 35% worldwide. Cholesterol metabolism is often disturbed during sepsis, with low plasma cholesterol levels being associated with poor prognosis. Proprotein convertase subtilisin/kexin type 9 (PCSK9) promotes degradation of the low-density lipoprotein receptor (LDLR), thus regulating intracellular and plasma cholesterol levels. PCSK9 is often upregulated during sepsis and might have a detrimental effect on immune host response and survival. Accordingly, PCSK9 reduces lipopolysaccharide uptake and clearance by human hepatocytes. Moreover, PCSK9 upregulation exacerbates organ dysfunction and tissue inflammation during sepsis, whereas a protective effect of PCSK9 deficiency has been documented in septic patients. Although a possible detrimental impact of PCSK9 on survival has been described, some beneficial effects of PCSK9 on immune response may be hypothesized. First, PCSK9 is associated with increased plasma cholesterol levels, which might be protective during sepsis. Second, PCSK9, by stimulating LDLR degradation and inhibiting reverse cholesterol transport (RCT), might promote preferential cholesterol accumulation in macrophages and other immune cells; these events might improve lipid raft composition and augment toll-like receptor function thus supporting inflammatory response. Hence, a more clear definition of the role of PCSK9 in septic states might provide additional insight in the understanding of the sepsis-associated immune dysregulation and enhance therapeutic outcomes.

Severe Atherosclerosis and Hypercholesterolemia in Mice Lacking Both the Melanocortin Type 4 Receptor and Low Density Lipoprotein Receptor.

Dysfunction of the melanocortin system can result in severe obesity accompanied with dyslipidemia and symptoms of the metabolic syndrome but the effect on vascular atherogenesis is not known. To study the impact of obesity and dyslipidemia on the cardiovascular system, we generated mice double-deficient for the melanocortin type 4 receptor (Mc4rmut mice) and the LDL receptor (Ldlr-/- mice). Mc4rmut mice develop obesity due to hyperphagia. Double-mutant mice (Mc4rmut;Ldlr-/-) exhibited massive increases in body weight, plasma cholesterol and triacylglycerol levels and developed atherosclerosis. Atherosclerotic lesion size was affected throughout the aortic root and brachiocephalic artery not only under semisynthetic, cholesterol-containing diet but also under cholesterol-free standard chow. The Mc4rmut mice developed a hepatic steatosis which contributes to increased plasma cholesterol levels even under cholesterol-free standard chow. Transcripts of cholesterol biosynthesis components and liver cholesterol levels did not significantly differ between wild-type and all mutant mouse strains but RNA sequencing data and biochemical measurements point to an altered bile acid elimination in Mc4rmut;Ldlr-/-. Therefore, the unchanged endogenous cholesterol biosynthesis together with a reduced hepatic VLDL and LDL-cholesterol clearance most likely led to increased plasma lipid levels and consequently to atherosclerosis in this animal model. Our data indicate that dysfunction of the melanocortin-regulated food intake and the resulting obesity significantly add to the proatherogenic lipoprotein profile caused by LDL receptor deficiency and, therefore, can be regarded as relevant risk factor for atherosclerosis.

PEGylated IL-10 Activates Kupffer Cells to Control Hypercholesterolemia.

Interleukin-10 (IL-10) is a multifunctional cytokine that exerts potent context specific immunostimulatory and immunosuppressive effects. We have investigated the mechanism by which PEGylated rIL-10 regulates plasma cholesterol in mice and humans. In agreement with previous work on rIL-10, we report that PEGylated rIL-10 harnesses the myeloid immune system to control total plasma cholesterol levels. We have discovered that PEG-rMuIL-10’s dramatic lowering of plasma cholesterol is dependent on phagocytotic cells. In particular, PEG-rHuIL-10 enhances cholesterol uptake by Kupffer cells. In addition, removal of phagocytotic cells dramatically increases plasma cholesterol levels, suggesting for the first time that immunological cells are implicitly involved in regulating total cholesterol levels. These data suggest that treatment with PEG-rIL-10 potentiates endogenous cholesterol regulating cell populations not currently targeted by standard of care therapeutics. Furthermore, we show that IL-10’s increase of Kupffer cell cholesterol phagocytosis is concomitant with decreases in liver cholesterol and triglycerides. This leads to the reversal of early periportal liver fibrosis and facilitates the restoration of liver health. These data recommend PEG-rIL-10 for evaluation in the treatment of fatty liver disease and preventing its progression to non-alcoholic steatohepatitis. In direct confirmation of our in vivo findings in the treatment of hypercholesterolemic mice with PEG-rMuIL-10, we report that treatment of hypercholesterolemic cancer patients with PEG-rHuIL-10 lowers total plasma cholesterol by up to 50%. Taken together these data suggest that PEG-rIL-10’s cholesterol regulating biology is consistent between mice and humans.

SUGP1 is a novel regulator of cholesterol metabolism.

A large haplotype on chromosome 19p13.11 tagged by rs10401969 in intron 8 of SURP and G patch domain containing 1 (SUGP1) is associated with coronary artery disease (CAD), plasma LDL cholesterol levels, and other energy metabolism phenotypes. Recent studies have suggested that TM6SF2 is the causal gene within the locus, but we postulated that this locus could harbor additional CAD risk genes, including the putative splicing factor SUGP1. Indeed, we found that rs10401969 regulates SUGP1 exon 8 skipping, causing non-sense-mediated mRNA decay. Hepatic Sugp1 overexpression in CD1 male mice increased plasma cholesterol levels 20–50%. In human hepatoma cell lines, SUGP1 knockdown stimulated 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) alternative splicing and decreased HMGCR transcript stability, thus reducing cholesterol synthesis and increasing LDL uptake. Our results strongly support a role for SUGP1 as a novel regulator of cholesterol metabolism and suggest that it contributes to the relationship between rs10401969 and plasma cholesterol.

Extract of Garcinia kola Seed has Antitussive Effect and Attenuates Hypercholesterolemia in Rodents

Background: The seeds of Garcinia kola Heckel (Guttiferrae) are widely eaten in West Africa for cultural and ethnomedicinal reasons including cough suppression and body fat reduction. We prepared a 70% ethanol extract and designed experiments to investigate the antitussive and anti-hypercholesterolemic effects. Methods: For the antitussive investigations, guinea pigs were exposed to 7.5% citric acid aerosol in a chamber and cough bouts were counted after acute doses of the extract. Mucus expectoration was evaluated in mice after administering the extract for seven days by measuring the concentration of phenol red dye released from mouse trachea. Hypercholesterolemia was induced and doses of the extract were administered for 14 days. Results: Single doses of 100, 200 and 400 mg/kg (p.o.) significantly (p<0.01) and dose-dependently suppressed cough bouts by 67, 78 and 92% respectively when compared cough bouts exhibited before treatment. The dose of 400 mg/kg was slightly but not significantly superior to the standard drug dihydrocodeine (84%) in cough suppression. The extract administered daily for 7 days also significantly (p<0.05) reduced concentration of phenol red released from mouse trachea in comparison with control. At 100, 200 and 400 mg/kg/day for 14 days, extract like 5 mg/kg simvastatin significantly (p<0.0001) attenuated the increase in plasma cholesterol level but only doses of 200 and 400 mg/kg/day significantly blunted increase in body weight compared to cholesterol treated rats. Conclusion: The extract possesses antitussive effect and attenuates hypercholesterolemia thereby lending credence to its ethnomedicinal uses.

Effect of a hypercholesterolemia as a starting factor on spinal degeneration in rabbits and role of Vitamin E (α-tocopherol).

Background:To identify the role of the hypercholesterolemia as a starting factor in discovertebral degeneration that ultimately causes lower back pain, and investigate the role of Vitamin E in this process.Methods:The rabbits (n = 32) were divided into two broad experimental groups: A control group, and a hypercholesterolemia group, namely cholesterol, and cholesterol plus Vitamin E groups and they were fed sequentially for 4 or 8 weeks. Serum cholesterol and Vitamin E (α-tocopherol) levels were determined; vascular tissue was prepared for histopathological analyses and vertebra was decalcified for the study.Results:Cholesterol diet group resulted approximately 44-fold of increase plasma cholesterol levels over the 4-week control values. Additional supplementation with Vitamin E group induced a plasma cholesterol level increase of only 37-fold as compared to the control group. In the cholesterol groups, light microscope examination revealed atherosclerotic plaque in major arteries. However, in the cholesterol plus Vitamin E treatment groups, no lipid accumulation or foam cell formation was visible in the abdominal aorta and vertebral segmental artery. In histopathological examination, we found degenerative changes in the discovertebral unit in cholesterol treated groups.Conclusion:Hypercholesterolemia causes fat accumulation in the disc endplate and vertebral body that causes blood supply disturbances which might be a starting factor of discovertebral degeneration. This event was not reversed by the elimination of cholesterol from the diet. Vitamin E supplementation was not effective in reducing fat accumulation in vertebral bone marrow. As a result, we conclude that degeneration of the discovertebral unit is not related to atherosclerotic changes in the major blood vessels.

Comment on "Hypercholesterolemia with consumption of PFOA-laced Western diets is dependent on strain and sex of mice" by Rebholz S.L. et al. Toxicol. Rep. 2016 (3) 46-54.

A recent article in Toxicology Reports by [26] reported increased plasma cholesterol levels (primarily as HDL) in C57BL/6 (male and female) and BALB/c (male only) mice given high fat (Westernized) diet which also contained PFOA. The authors concluded that PFOA ingestion leads to hypercholesterolemia and they stated these data were “consistent with human observational findings”. There are several key factors which have not been considered in their study and we offer this letter to identify this important information. In particular, we feel that this conclusion needs more balance, particularly with respect to the relevance and translatability of their findings to the human situation.