The Effects of Combined Therapy With Metformin and Hydroxypropyl-β-Cyclodextrin in a Mouse Model of Niemann-Pick Disease Type C1

Niemann–Pick disease type C1 (NPC1) is a neurodegenerative disorder characterized by lysosomal storage of free cholesterol. 2-Hydroxypropyl-β-cyclodextrin (HPβCD) is a cyclic oligosaccharide derivative that is being developed to treat NPC1. Recently, metformin was reported to be beneficial in various neurodegenerative diseases, such as Alzheimer’s and Huntington’s diseases. In this study, we examined the effects of combined treatment with HPβCD and metformin on Npc1−/− mice. Unfortunately, body weight and survival rates showed that cotreatment with metformin did not extend survival time and increase the body weight of HPβCD-treated Npc1−/− mice. However, cotreatment with metformin reduced inflammatory response and inhibited the proinflammatory cytokine release in the brain, liver and spleen of HPβCD-treated Npc1−/− mice. Furthermore, metformin did not reduce the free cholesterol levels in Npc1−/− brain tissue or fibroblasts. In conclusion, our results demonstrate that metformin does not show beneficial effects on body weight or survival time but reduced the inflammatory response in a mouse model of NPC1 when combined with HPβCD.

Ubiquitous Aberration in Cholesterol Metabolism across Pancreatic Ductal Adenocarcinoma

Pancreatic cancer (PC) is characterized by metabolic deregulations that often manifest as deviations in metabolite levels and aberrations in their corresponding metabolic genes across the clinical specimens and preclinical PC models. Cholesterol is one of the critical metabolites supporting PC, synthesized or acquired by PC cells. Nevertheless, the significance of the de novo cholesterol synthesis pathway has been controversial in PC, indicating the need to reassess this pathway in PC. We utilized preclinical models and clinical specimens of PC patients and cell lines and utilized mass spectrometry-based sterol analysis. Further, we also performed in silico analysis to corroborate the significance of de novo cholesterol synthesis pathway in PC. Our results demonstrated alteration in free sterol levels, including free cholesterol, across in vitro, in vivo, and clinical specimens of PC. Especially, our sterol analyses established consistent alterations in free cholesterol across the different PC models. Overall, this study demonstrates the significance and consistency in deviation of cholesterol synthesis pathway in PC while showing the aberrations in sterol metabolite intermediates and the related genes using preclinical models, in silico platforms, and the clinical specimens.

The Differential Effects of HDL Subpopulations on Lipoprotein Lipase (LPL)-Mediated VLDL Catabolism

High-density lipoprotein (HDL) subpopulations functional assessment is more relevant for HDL anti-atherogenic activity than cholesterol level. The aim of the study was to assess the impact of HDL-2 and HDL-3 on lipoprotein lipase (LPL)-mediated very-low-density lipoprotein (VLDL) catabolism related to hypertriglyceridemia development. VLDL and HDLs were isolated from serum by ultracentrifugation. VLDL was incubated with LPL in the absence and presence of total HDL or HDL subpopulations. Next, VLDL remnants were separated, and their composition and electrophoretic mobility was assessed. Both HDL subpopulations increased the efficiency of triglyceride lipolysis and apolipoprotein CII and CIII removal from VLDL up to ~90%. HDL-3 exerted significantly greater impact than HDL-2 on apolipoprotein E (43% vs. 18%, p < 0.001), free cholesterol (26% vs. 18%, p < 0.05) and phospholipids (53% vs. 43%, p < 0.05) removal from VLDL and VLDL remnant electrophoretic mobility (0.18 vs. 0.20, p < 0.01). A greater release of these components was also observed in the presence of total HDL with a low HDL-2/HDL-3 cholesterol ratio. Both HDL subpopulations affect VLDL composition during lipolysis, but HDL-3 exhibited a greater effect on this process. Altered composition of HDL related to significant changes in the distribution between HDL-2 and HDL-3 can influence the VLDL remnant features, affecting atherosclerosis progression.

Anticholesterolemic Activity of Three Vegetal Extracts (Artichoke, Caigua, and Fenugreek) and Their Unique Blend

Hepatic-related diseases, in particular hyperlipidemia and hypercholesterolemia, are a thorn on the side of the national health institutes around the globe. Indeed, liver lipid and cholesterol dysregulation could lead to atherosclerotic plaque formation and cardiovascular diseases. Currently, statin administration and monacolin K consumption are the main therapies proposed to counter this alarming connection, but relevant side effects are known. To overcome this issue, safe nutraceutical formulations and/or vegetal extracts, endowed with anticholesterolemic activity, could be instrumental in hypercholesterolemia prevention and treatment. In the present work, the anticholesterolemic efficacy of three vegetal extracts used in traditional medicine (artichoke, caigua, and fenugreek), their unique blend (ACFB), and the monacolin K-containing red yeast extract (RYR), was investigated with an in vitro approach based on hepatic cell line HepG2. The impact on cholesterol of the three extracts, their blend, and RYR were investigated by determining hepatocyte total and free cholesterol and bile acids biosynthesis. According to our results, the anticholesterolemic activity of the vegetal extracts was confirmed, and a novel choleretic activity of caigua extract was evidenced. ACFB showed to be safer than RYR while showing a similar effect on total and free cholesterol and bile acids synthesis compared to it. The anticholesterolemic activity of the blend was obtained with lower vegetal extract concentrations compared with the single vegetal extract, potentially indicating an additive effect between the extracts. In conclusion, the vegetal extracts and their blend, ACFB, are safe and are endowed with anticholesterolemic activity, potentially providing complementary therapies to the statin-based ones for hyperlipidemia and hypercholesterolemia-related complications.

The protective effect of Vitamin D and combination with liv-52 on lipid profiles in carbon tetrachloride-induced liver disease in Wistar rats

Background: Liver is the largest gland, accounts for approximately 2.5% of total body weight and also liver called as the metabolic “engine-room of the body.” Liver plays role in both metabolism as well as biochemical transformation. Therefore, it is vital to maintain a healthy liver for overall health and well-being. However, liver is continuously exposed to exogenous substances such as toxins, drugs, and alcohol which can ultimately lead to various liver disorders. Liver diseases today are one of the most fatal diseases globally. Aims and Objectives: The aim of the present study was to evaluate lipid peroxidation (LPO) and lipid profile levels of Vitamin D and combination with Liv-52 on carbon tetrachloride induced liver disease in rats. Materials and Methods: Thirty-six adult male Albino Wistar rats weighing 150–200 g were used in this study. Liver disease was induced in rats by administration of Carbon tetrachloride (CCl4) intraperitoneally at the dose of 1 mL mixed with 50% of olive oil twice a week for 5 weeks, 3 days interval between each dose, after confirmation of liver disease treated with Vitamin D and Liv-52 for 5 weeks. Results: The levels of LPO were significantly decreased in Vitamin D and Liv-52 treated animals when compared with CCl4 induced animals. Total cholesterol, free cholesterol, phospholipids, and triglycerides (TGs) levels were significantly reduced when compared with CCl4 induced rats. However, the levels of ester cholesterol and free fatty acids (FFAs) were significantly increased in Vitamin D and Liv-52 treated animals when compared with CCl4 induced animals. Conclusion: Vitamin D and Liv-52 effectively reduced the LPO levels. Treatment with Vitamin D and Liv-52, the levels of total and free cholesterol, phospholipids, and TGs were significantly reduced and treatment with both combinations highly reduced all these levels when compared with CCl4 induced animals. And treatment with Vitamin D and Liv-52, the ester cholesterol and FFAs levels were increased.

High Free Cholesterol Bioavailability Drives the Tissue Pathologies in Scarb1 −/− Mice

Objective: Overall and atherosclerosis-associated mortality is elevated in humans with very high HDL (high-density lipoprotein) cholesterol concentrations. Mice with a deficiency of the HDL receptor, Scarb1 (scavenger receptor class B type 1), are a robust model of this phenotype and exhibit several additional pathologies. We hypothesized that the previously reported high plasma concentration of free cholesterol (FC)–rich HDL in Scarb1 −/ − mice produces a state of high HDL-FC bioavailability that increases whole-body FC and dysfunction in multiple tissue sites. Approach and Results: The higher mol% FC in Scarb1 −/− versus WT (wild type) HDL (41.1 versus 16.0 mol%) affords greater FC bioavailability for transfer to multiple sites. Plasma clearance of autologous HDL-FC mass was faster in WT versus Scarb1 −/− mice. FC influx from Scarb1 −/− HDL to LDL (low-density lipoprotein) and J774 macrophages was greater (≈4×) than that from WT HDL, whereas FC efflux capacity was similar. The higher mol% FC of ovaries, erythrocytes, heart, and macrophages of Scarb1 −/− versus WT mice is associated with previously reported female infertility, impaired cell maturation, cardiac dysfunction, and atherosclerosis. The FC contents of other tissues were similar in the two genotypes, and these tissues were not associated with any overt pathology. In addition to the differences between WT versus Scarb1 −/− mice, there were many sex-dependent differences in tissue-lipid composition and plasma FC clearance rates. Conclusions: Higher HDL-FC bioavailability among Scarb1 −/− versus WT mice drives increased FC content of multiple cell sites and is a potential biomarker that is mechanistically linked to multiple pathologies.

Secretory NPC2 Protein-Mediated Free Cholesterol Levels Were Correlated with the Sorafenib Response in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary malignant tumor in the world. Sorafenib is the first-line drug for patients with advanced HCC. However, long-term treatment with sorafenib often results in reduced sensitivity of tumor cells to the drug, leading to acquired resistance. Identifying biomarkers which can predict the response to sorafenib treatment may represent a clinical challenge in the personalized treatment era. Niemann-Pick type C2 (NPC2), a secretory glycoprotein, plays an important role in regulating intracellular free cholesterol homeostasis. In HCC patients, downregulation of hepatic NPC2 is correlated with poor clinical pathological features through regulating mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) activation. This study aimed to investigate the roles of secretory NPC2-mediated free cholesterol levels as biomarkers when undergoing sorafenib treatment and evaluate its impact on acquired sorafenib resistance in HCC cells. Herein, we showed that NPC2 downregulation and free cholesterol accumulation weakened sorafenib’s efficacy through enhancing MAPK/AKT signaling in HCC cells. Meanwhile, NPC2 overexpression slightly enhanced the sorafenib-induced cytotoxic effect. Compared to normal diet feeding, mice fed a high-cholesterol diet had much higher tumor growth rates, whereas treatment with the free cholesterol-lowering agent, hydroxypropyl-β-cyclodextrin, enhanced sorafenib’s tumor-inhibiting ability. In addition, sorafenib treatment induced higher NPC2 secretion, which was mediated by inhibition of the Ras/Raf/MAPK kinase (MEK)/ERK signaling pathway in HCC cells. In both acquired sorafenib-resistant cell and xenograft models, NPC2 and free cholesterol secretion were increased in culture supernatant and serum samples. In conclusion, NPC2-mediated free cholesterol secretion may represent a candidate biomarker for the likelihood of HCC cells developing resistance to sorafenib.

Compositional and functional properties of high-density lipoproteins in relation to coronary in-stent restenosis

IntroductionIn-stent restenosis (ISR) is an unfavorable outcome that occurs in patients after coronary stenting. Using of drugs like statins as well as drug-eluting stents has only been partially effective in reducing the rate of ISR. Since low high-density lipoprotein cholesterol (HDL-C) concentration is a pivotal cardiovascular disease risk factor, this study aimed the evaluation of the compositional and functional alterations of HDL in individuals with ISR.Material and methodsThis case-control study comprised 21 ISR, 26 non-ISR, 16 angiography-negative, and 18 healthy subjects. Serum HDL2 (d: 1.063-1.125 g/mL) and HDL3 (d: 1.125-1.210 g/mL) subfractions were extracted from each subject using sequential ultracentrifugation. The capacity of HDL to efflux cellular cholesterol from lipid-loaded macrophages as well as to uptake free cholesterol (FC) from triglyceride-rich lipoproteins (TGRL) during lipolysis were assessed.ResultsNo difference was found in the HDL2 and HDL3 content of free cholesterol and total protein among the groups. NISR group showed reduced triglyceride content in HDL2 and increased phospholipid content in HDL3 relative to healthy subjects. Strong positive correlations were found between the cholesterol efflux capacity (CEC) of HDL2 and its phospholipid content in the healthy (r=0.50), angiography-negative (r=0.55) and ISR (r=0.52) groups. The capacity of apolipoprotein B (apoB)-depleted serum to uptake free cholesterol was not different among the groupsConclusionsDespite some compositional alterations, the capacity of HDL to efflux cholesterol from lipid-loaded macrophages as well as to uptake free cholesterol from TGRLs during lipolysis were not associated with ISR in this study