HDL as a target in the treatment of atherosclerotic cardiovascular disease

Targeted delivery of rapamycin and inhibition of platelet adhesion with multifunctional peptide nanoparticles for atherosclerosis treatment

There is increasing evidence supporting the unique benefits of targeted therapy in treating atherosclerotic disease. Given the complex nature of atherosclerosis development, we proposed a novel strategy for the efficient delivery of rapamycin (RAPA) by targeting both the exposed subendothelial collagen and oxidized low-density lipoprotein (oxLDL) present in plaques. In response, we developed multifunctional peptide (MP) nanoparticles for targeted drug delivery. The ability of MP nanoparticles to load RAPA and target collagen/oxLDL was investigated through molecular dynamics simulations and in vitro experiments. The efficacy of MP nanoparticles in atherosclerosis treatment was assessed via in vivo experiments on ApoE-/- mice. Results indicate that MP nanoparticles have encapsulation and drug loading efficiencies for RAPA of 78.3 % and 43.9 %, respectively. By targeting collagen, MP nanoparticles create steric hindrance that inhibits 77.2 % of platelet adhesion. These nanoparticles can also target oxLDL, delivering RAPA into plaques and significantly reducing macrophage uptake of oxLDL. In vivo experiments showed that MP nanoparticles effectively targeted and accumulated in plaques. Treating mice with MP@RAPA nanoparticles for 10 weeks led to an 81.3 % reduction in the aortic vascular plaque area and decreased concentrations of MCP-1, hs-CRP, MMP-1, P-selectin, IL-1β, and IL-8 inflammatory factors, as well as the optical density of platelet-associated proteins (CD42, CD61, and PECAM-1). These results highlight the promising potential of MP nanoparticles for atherosclerotic disease treatment.

The Role of Selected lncRNAs in Lipid Metabolism and Cardiovascular Disease Risk

Lipid disorders increase the risk for the development of cardiometabolic disorders, including type 2 diabetes, atherosclerosis, and cardiovascular disease. Lipids levels, apart from diet, smoking, obesity, alcohol consumption, and lack of exercise, are also influenced by genetic factors. Recent studies suggested the role of long noncoding RNAs (lncRNAs) in the regulation of lipid formation and metabolism. Despite their lack of protein-coding capacity, lncRNAs are crucial regulators of various physiological and pathological processes since they affect the transcription and epigenetic chromatin remodelling. LncRNAs act as molecular signal, scaffold, decoy, enhancer, and guide molecules. This review summarises available data concerning the impact of lncRNAs on lipid levels and metabolism, as well as impact on cardiovascular disease risk. This relationship is significant because altered lipid metabolism is a well-known risk factor for cardiovascular diseases, and lncRNAs may play a crucial regulatory role. Understanding these mechanisms could pave the way for new therapeutic strategies to mitigate cardiovascular disease risk through targeted modulation of lncRNAs. The identification of dysregulated lncRNAs may pose promising candidates for therapeutic interventions, since strategies enabling the restoration of their levels could offer an effective means to impede disease progression without disrupting normal biological functions. LncRNAs may also serve as valuable biomarker candidates for various pathological states, including cardiovascular disease. However, still much remains unknown about the functions of most lncRNAs, thus extensive studies are necessary elucidate their roles in physiology, development, and disease.

Phytol from Scoparia dulcis prevents NF-κB-mediated inflammatory responses during macrophage polarization

Macrophages are primary immune cells that mediate a wide range of inflammatory diseases through their polarization potential. In this study, phytol isolated from Scoparia dulcis has been explored against 7-ketocholesterol and bacterial lipopolysaccharide-induced macrophage polarization in IC-21 cells. Isolated phytol has been characterized using GC-MS, TLC, HPTLC, FTIR, 1H-NMR, and HPLC analyses. The immunomodulatory effects of viable concentrations of phytol were tested on oxidative stress, arginase activity, nuclear and mitochondrial membrane potentials in IC-21 cells in addition to the modulation of calcium and lipids. Further, gene and protein expression of atherogenic markers were studied. Results showed that the isolated phytol at a viable concentration of 400 µg/ml effectively reduced the production of nitric oxide, superoxide anion (ROS generation), calcium and lipid accumulation, stabilized nuclear and mitochondrial membranes, and increased arginase activity. The atherogenic markers including iNOS, COX-2, IL-6, IL-1β, MMP-9, CD36, and NF-κB were significantly downregulated at the levels of gene and protein expression, while macrophage surface and nuclear receptor markers (CD206, CD163, and PPAR-γ) were significantly upregulated by phytol pre-treatment in macrophages. Therefore, the present pharmacognostic study supports the role of phytol isolated from Scoparia dulcis in preventing M2-M1 macrophage polarization under inflammatory conditions, making it a promising compound.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-03924-9.

The roles of nuclear receptors in cholesterol metabolism and reverse cholesterol transport in nonalcoholic fatty liver disease

As the most prevalent chronic liver disease globally, NAFLD encompasses a pathological process that ranges from simple steatosis to NASH, fibrosis, cirrhosis, and HCC, closely associated with numerous extrahepatic diseases. While the initial etiology was believed to be hepatocyte injury caused by lipid toxicity from accumulated triglycerides, recent studies suggest that an imbalance of cholesterol homeostasis is of greater significance. The role of nuclear receptors in regulating liver cholesterol homeostasis has been demonstrated to be crucial. This review summarizes the roles and regulatory mechanisms of nuclear receptors in the 3 main aspects of cholesterol production, excretion, and storage in the liver, as well as their cross talk in reverse cholesterol transport. It is hoped that this review will offer new insights and theoretical foundations for the study of the pathogenesis and progression of NAFLD and provide new research directions for extrahepatic diseases associated with NAFLD.

Apolipoprotein A-1 Accelerated Liver Regeneration Through Regulating Autophagy Via AMPK-ULK1 Pathway

BACKGROUND & AIMS

Apolipoprotein A-1 (ApoA-1), the main apolipoprotein of high-density lipoprotein, has been well studied in the area of lipid metabolism and cardiovascular diseases. In this project, we clarify the function and mechanism of ApoA-1 in liver regeneration.

METHODS

Seventy percent of partial hepatectomy was applied in male ApoA-1 knockout mice and wild-type mice to investigate the effects of ApoA-1 on liver regeneration. D-4F (ApoA-1 mimetic peptide), autophagy activator, and AMPK activator were used to explore the mechanism of ApoA-1 on liver regeneration.

RESULTS

We demonstrated that ApoA-1 levels were highly expressed during the early stage of liver regeneration. ApoA-1 deficiency greatly impaired liver regeneration after hepatectomy. Meanwhile, we found that ApoA-1 deficiency inhibited autophagy during liver regeneration. The activation of autophagy protected against ApoA-1 deficiency in inhibiting liver regeneration. Furthermore, ApoA-1 deficiency impaired autophagy through AMPK-ULK1 pathway, and AMPK activation significantly improved liver regeneration. The administration of D-4F could accelerated liver regeneration after hepatectomy.

CONCLUSIONS

These findings suggested that ApoA-1 played an essential role in liver regeneration through promoting autophagy in hepatocytes via AMPK-ULK1 pathway. Our findings enrich the understanding of the underlying mechanism of liver regeneration and provide a potential therapeutic strategy for liver injury.

Haemodynamic Effects on the Development and Stability of Atherosclerotic Plaques in Arterial Blood Vessel

Studying the formation and stability of atherosclerotic plaques in the hemodynamic field is essential for understanding the growth mechanism and preventive treatment of atherosclerotic plaques. In this paper, based on a multiplayer porous wall model, we established a two-way fluid-solid interaction with time-varying inlet flow. The lipid-rich necrotic core (LRNC) and stress in atherosclerotic plaque were described for analyzing the stability of atherosclerotic plaques during the plaque growth by solving advection-diffusion-reaction equations with finite-element method. It was found that LRNC appeared when the lipid levels of apoptotic materials (such as macrophages, foam cells) in the plaque reached a specified lower concentration, and increased with the plaque growth. LRNC was positively correlated with the blood pressure and was negatively correlated with the blood flow velocity. The maximum stress was mainly located at the necrotic core and gradually moved toward the left shoulder of the plaque with the plaque growth, which increases the plaque instability and the risk of the plaque shedding. The computational model may contribute to understanding the mechanisms of early atherosclerotic plaque growth and the risk of instability in the plaque growth.

Lipoproteins and Their Effects on the Cardiovascular System

Coronary heart disease is the foremost leading cause of death across the world. It mainly involves the blood vessels, which supply the heart. Plaque formation due to lipid deposition leads to the narrowing of the vessels, obstructing blood flow. Therefore, lipoproteins such as high-density lipoproteins (HDL), low-density lipoproteins (LDL), very low-density lipoproteins (VLDL), and chylomicrons play a crucial role in cardiovascular diseases. Lipoproteins are carrier molecules made up of proteins and fats. They carry cholesterol through the bloodstream and transport it to the peripheral tissues or the liver. There are several classes of lipoproteins in the blood, namely HDL, LDL, VLDL, and chylomicrons. Depending on the lipoproteins, an excess of them can either harm or benefit the body. Low-density lipoprotein, nicknamed 'the bad cholesterol,' transports fatty molecules from the liver and deposits them in peripheral tissues or central vessels. Thus, excess LDL can cause blockage of the arteries supplying major organs. High-density lipoprotein, nicknamed 'the good cholesterol,' transports the excess fatty molecules to the liver for their metabolism and removal from the body. Hence, high levels of HDL are an indication of a healthy body. Thus, lipoproteins are important molecules, and their proper regulation is essential to maintaining a healthy body. An effective way to maintain a balanced lipoprotein level is to have a properly balanced diet with high protein and low fat. Regular exercise, both indoors and outdoors, is recommended. If cholesterol levels are not maintained by diet and exercise, medication is advised after consulting medical experts. This review aims to inform people about lipoproteins, their importance, and maintaining a healthy lipoprotein level.

A Scalable High-Throughput Isoelectric Fractionation Platform for Extracellular Nanocarriers: Comprehensive and Bias-Free Isolation of Ribonucleoproteins from Plasma, Urine, and Saliva

Extracellular nanocarriers (extracellular vesicles (EVs), lipoproteins, and ribonucleoproteins) of protein and nucleic acids mediate intercellular communication and are clinically adaptable as distinct circulating biomarkers. However, the overlapping size and density of the nanocarriers have so far prevented their efficient physical fractionation, thus impeding independent downstream molecular assays. Here, we report a bias-free high-throughput and high-yield continuous isoelectric fractionation nanocarrier fractionation technique based on their distinct isoelectric points. This nanocarrier fractionation platform is enabled by a robust and tunable linear pH profile provided by water-splitting at a bipolar membrane and stabilized by flow without ampholytes. The linear pH profile that allows easy tuning is a result of rapid equilibration of the water dissociation reaction and stabilization by flow. The platform is automated with a machine learning procedure to allow recalibration for different physiological fluids and nanocarriers. The optimized technique has a resolution of 0.3 ΔpI, sufficient to separate all nanocarriers and even subclasses of nanocarriers. Its performance is then evaluated with several biofluids, including plasma, urine, and saliva samples. Comprehensive, high-purity (plasma: >93%, urine: >95% and saliva: >97%), high-yield (plasma: >78%, urine: >87% and saliva: >96%), and probe-free isolation of ribonucleoproteins in 0.75 mL samples of various biofluids in 30 min is demonstrated, significantly outperforming affinity-based and highly biased gold standards having low yield and day-long protocols. Binary fractionation of EVs and different lipoproteins is also achieved with similar performance.

Beneficial effects of luseogliflozin on lipid profile and liver function in patients with type 2 diabetes mellitus (BLUE trial): a single-center, single-arm, open-label prospective study

BACKGROUND

Arteriosclerosis and non-alcoholic fatty liver disease are major complications of diabetes mellitus. Hyperglycemia, insulin resistance, obesity, and metabolic syndrome are associated with the progression of these complications. Sodium-glucose transporter 2 inhibitors such as luseogliflozin are oral hypoglycemic agents that reduce glucose levels, induce loss of weight or body fat, and improve liver function. However, the effects of these agents on lipid profiles are unclear. Therefore, this study aimed to investigate these effects and their relationship with arteriosclerosis and non-alcoholic fatty liver disease.

METHODS

This single-center, single-arm, open-labeled prospective study enrolled 25 outpatients with type 2 diabetes mellitus who visited Minami Osaka Hospital. Laboratory tests and body measurements were performed at weeks 0 and 24. Luseogliflozin was started at 2.5 mg/day after breakfast, and data from weeks 0 and 24 were evaluated. There were no changes in the doses of other antidiabetic and dyslipidemia drugs a month prior to or during the study.

RESULTS

The patients showed significant reductions in the levels of triglycerides, remnant-like particle cholesterol, and triglyceride/high-density lipoprotein cholesterol ratio, along with significant increases in the levels of high-density lipoprotein cholesterol and apolipoprotein A-1. Alanine aminotransferase, γ-glutamyl transpeptidase, and the fatty liver index were significantly reduced.

CONCLUSIONS

Luseogliflozin-induced changes in the lipid profile were related to the suppression or improvement of arteriosclerosis and liver function, respectively. Patients who received this drug also showed improvements in the levels of liver enzymes and reductions in the fatty liver index. Earlier use of luseogliflozin might prevent diabetic complications. Trial registration This study was registered in the University Hospital Medical Information Network Clinical Trial Registry (UMIN 000043595) on April 6th, 2021.

Bound Phospholipids Assist Cholesteryl Ester Transfer in the Cholesteryl Ester Transfer Protein

Cholesteryl ester transfer protein (CETP) is a plasma glycoprotein that assists the transfer of cholesteryl esters (CEs) from antiatherogenic high-density lipoproteins (HDLs) to proatherogenic low-density lipoproteins (LDLs), initiating cholesterol plaques in the arteries. Consequently, inhibiting the activity of CETP is therefore being pursued as a novel strategy to reduce the risk of cardiovascular diseases (CVDs). The crystal structure of CETP has revealed the presence of two CEs running in the hydrophobic tunnel and two plugged-in phospholipids (PLs) near the concave surface. Other than previous animal models that rule out the PL transfer by CETP and PLs in providing the structural stability, the functional importance of bound phospholipids in CETP is not fully explored. Here, we employ a series of molecular dynamics (MD) simulations, steered molecular dynamics (SMD) simulations, and free energy calculations to unravel the effect of PLs on the functionality of the protein. Our results suggest that PLs play an important role in the transfer of neutral lipids by transforming the unfavorable bent conformation of CEs into a favorable linear conformation to facilitate the smooth transfer. The results also suggest that the making and breaking interactions of the hydrophobic tunnel residues with CEs with a combined effort from PLs are responsible for the transfer of CEs. Further, the findings demonstrate that the N-PL has a more pronounced effort on CE transfer than C-PL but efforts from both PLs are essential in the transfer. Thus, we propose that the functionally important PLs can be considered with potential research interest in targeting cardiovascular diseases.

Distinct metabolic features of genetic liability to type 2 diabetes and coronary artery disease: a reverse Mendelian randomization study

BACKGROUND

Type 2 diabetes (T2D) and coronary artery disease (CAD) both have known genetic determinants, but the mechanisms through which their associated genetic variants lead to disease onset remain poorly understood.

METHODS

We used large-scale metabolomics data in a two-sample reverse Mendelian randomization (MR) framework to estimate effects of genetic liability to T2D and CAD on 249 circulating metabolites in the UK Biobank (N = 118,466). We examined the potential for medication use to distort effect estimates by conducting age-stratified metabolite analyses.

FINDINGS

Using inverse variance weighted (IVW) models, higher genetic liability to T2D was estimated to decrease high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) (e.g.

, HDL-C

 -0.05 SD; 95% CI -0.07 to -0.03, per doubling of liability), whilst increasing all triglyceride groups and branched chain amino acids (BCAAs). IVW estimates for CAD liability suggested an effect on reducing HDL-C as well as raising very-low density lipoprotein cholesterol (VLDL-C) and LDL-C. In pleiotropy-robust models, T2D liability was still estimated to increase BCAAs, but several estimates for higher CAD liability reversed and supported decreased LDL-C and apolipoprotein-B. Estimated effects of CAD liability differed substantially by age for non-HDL-C traits, with higher CAD liability lowering LDL-C only at older ages when statin use was common.

INTERPRETATION

Overall, our results support largely distinct metabolic features of genetic liability to T2D and CAD, illustrating both challenges and opportunities for preventing these commonly co-occurring diseases.

FUNDING

Wellcome Trust [218495/Z/19/Z], UK MRC [MC_UU_00011/1; MC_UU_00011/4], the University of Bristol, Diabetes UK [17/0005587], World Cancer Research Fund [IIG_2019_2009].

Association of serum laboratory parameters with periprocedural myocardial infarction after a primary percutaneous coronary intervention

BACKGROUND

Periprocedural myocardial infarction (PMI) is one of the mortality-related complications of percutaneous coronary intervention (PCI) and significantly affects short- and long-term adverse outcomes and immediate cardiovascular events. Our present study aimed to evaluate the association of preprocedural serum laboratory parameters and PMI in patients who received primary PCI and attempted to provide detailed data on the predictors of PCI-related PMI.

METHODS

A total of 1184 consecutive coronary artery disease (CAD) patients who received primary and elective PCI between July 2015 and June 2017 were included and divided into control group and PMI group. The data of serum laboratory parameters were collected from the electronic database of Meizhou People's Hospital.

RESULTS

The results indicated that preprocedural fasting blood glucose were higher in PMI group compared with the control group (p < .001). Patients with prior hyperlipidemia were more likely to have experienced PCI-related PMI (p = .018) and the preprocedural level of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), non-HDL-C, apolipoprotein B (Apo B), and LDL-C/high density lipoprotein cholesterol (HDL-C) were significantly enhanced in PMI group (p < .001). Multivariate regression analysis revealed that preprocedural fasting blood glucose > 6.11 mmol/L (p < .001, OR = 1.949, 95% CI: 1.444-2.630) and LDL-C levels ≥130 mg/dL (p = .005, OR = 1.941, 95% CI: 1.217-3.098) independently predicted PCI-related PMI.

CONCLUSION

Our results indicated preprocedural fasting blood glucose >6.11 mmol/L and LDL-C levels ≥130 mg/dL may be useful predictors for PCI-related PMI. The study may provide a detailed data on the predictors of PCI-related PMI.

Extensive diet-induced atherosclerosis in scavenger receptor class B type 1-deficient mice is associated with substantial leukocytosis and elevated vascular cell adhesion molecule-1 expression in coronary artery endothelium

High levels of low density lipoprotein (LDL) cholesterol and low levels of high density lipoprotein (HDL) cholesterol are risk factors for cardiovascular disease. Mice that lack genes involved in the clearance of LDL from the bloodstream, such as the LDL receptor and apolipoprotein E, are widely used models of experimental atherosclerosis. Conversely, mice that lack the HDL receptor, scavenger receptor class B type I, and therefore have disrupted HDL functionality, also develop diet-inducible atherosclerosis but are a seldom-used disease model. In this study, we compared atherosclerosis and associated phenotypes in scavenger receptor class B type I knockout mice with those of wild type, LDL receptor knockout, and apolipoprotein E knockout mice after 20 weeks of being fed an atherogenic diet containing sodium cholate. We found that while scavenger receptor class B type I knockout mice had substantially lower plasma cholesterol than LDL receptor and apolipoprotein E knockout mice, they developed atherosclerotic plaques with similar sizes and compositions in their aortic sinuses, and more extensive atherosclerosis in their descending aortas and coronary arteries. This was associated with elevated tumor necrosis factor alpha levels in scavenger receptor class B type I knockout mice compared to wild type and LDL receptor knockout mice, and lymphocytosis, monocytosis, and elevated vascular cell adhesion molecule expression in coronary artery endothelial cells compared to the other mice examined. We conclude that extensive atherosclerosis in arteries that are not generally susceptible to atherosclerosis in scavenger receptor class B type I knockout mice is driven by factors in addition to hypercholesterolemia, including inflammation, dysregulation of the immune system and increased sensitivity of endothelial cells in arteries that are normally resistant to atherosclerosis. Scavenger receptor class B type I knockout mice fed a cholate containing atherogenic diet may prove to be a useful model to study mechanisms of atherosclerosis and evaluate treatments that rely on intact LDL clearance pathways.

Apolipoprotein A-1 protected hepatic ischaemia-reperfusion injury through suppressing macrophage pyroptosis via TLR4-NF-κB pathway

BACKGROUND AND AIMS

Apolipoprotein A-1 (ApoA-1), the major apolipoprotein of high-density lipoprotein, plays anti-atherogenic role in cardiovascular diseases and exerts anti-inflammation effect in various inflammatory and infectious diseases. However, the role and mechanism of ApoA-1 in hepatic ischaemia-reperfusion (I/R) injury is unknown.

METHODS

In this study, we measured ApoA-1 expression in human liver grafts after transplantation. Mice partial hepatic I/R injury model was made in ApoA-1 knockout mice, ApoA-1 mimetic peptide D-4F treatment mice and corresponding control mice to examine the effect of ApoA-1 on liver damage, inflammation response and cell death. Primary hepatocytes and macrophages were isolated for in vitro study.

RESULTS

The results showed that ApoA-1 expression was down-regulated in human liver grafts after transplantation and mice livers subjected to hepatic I/R injury. ApoA-1 deficiency aggravated liver damage and inflammation response induced by hepatic I/R injury. Interestingly, we found that ApoA-1 deficiency increased pyroptosis instead of apoptosis during acute phase of hepatic I/R injury, which mainly occurred in macrophages rather than hepatocytes. The inhibition of pyroptosis compensated for the adverse impact of ApoA-1 deficiency. Furthermore, the up-regulated pyroptosis process was testified to be mediated by ApoA-1 through TLR4-NF-κB pathway and TLR4 inhibition significantly improved hepatic I/R injury. In addition, we confirmed that D-4F ameliorated hepatic I/R injury.

CONCLUSIONS

Our study has identified the protective role of ApoA-1 in hepatic I/R injury through inhibiting pyroptosis in macrophages via TLR4-NF-κB pathway. The effect of ApoA-1 may provide a novel therapeutic approach for hepatic I/R injury.

Crosstalk Between Cholesterol, ABC Transporters, and PIP2 in Inflammation and Atherosclerosis

The lowering of plasma low-density lipoprotein cholesterol (LDL-C) is an easily achievable and highly reliable modifiable risk factor for preventing cardiovascular disease (CVD), as validated by the unparalleled success of statins in the last three decades. However, the 2021 American Heart Association (AHA) statistics show a worrying upward trend in CVD deaths, calling into question the widely held belief that statins and available adjuvant therapies can fully resolve the CVD problem. Human biomarker studies have shown that indicators of inflammation, such as human C-reactive protein (hCRP), can serve as a reliable risk predictor for CVD, independent of all traditional risk factors. Oxidized cholesterol mediates chronic inflammation and promotes atherosclerosis, while anti-inflammatory therapies, such as an anti-interleukin-1 beta (anti-IL-1β) antibody, can reduce CVD in humans. Cholesterol removal from artery plaques, via an athero-protective reverse cholesterol transport (RCT) pathway, can dampen inflammation. Phosphatidylinositol 4,5-bisphosphate (PIP2) plays a role in RCT by promoting adenosine triphosphate (ATP)-binding cassette transporter A1 (ABCA1)-mediated cholesterol efflux from arterial macrophages. Cholesterol crystals activate the nod-like receptor family pyrin domain containing 3 (Nlrp3) inflammasome in advanced atherosclerotic plaques, leading to IL-1β release in a PIP2-dependent fashion. PIP2 thus is a central player in CVD pathogenesis, serving as a critical link between cellular cholesterol levels, ATP-binding cassette (ABC) transporters, and inflammasome-induced IL-1β release.

Role of ABCA1 in Cardiovascular Disease

Cholesterol homeostasis plays a significant role in cardiovascular disease. Previous studies have indicated that ATP-binding cassette transporter A1 (ABCA1) is one of the most important proteins that maintains cholesterol homeostasis. ABCA1 mediates nascent high-density lipoprotein biogenesis. Upon binding with apolipoprotein A-I, ABCA1 facilitates the efflux of excess intracellular cholesterol and phospholipids and controls the rate-limiting step of reverse cholesterol transport. In addition, ABCA1 interacts with the apolipoprotein receptor and suppresses inflammation through a series of signaling pathways. Thus, ABCA1 may prevent cardiovascular disease by inhibiting inflammation and maintaining lipid homeostasis. Several studies have indicated that post-transcriptional modifications play a critical role in the regulation of ABCA1 transportation and plasma membrane localization, which affects its biological function. Meanwhile, carriers of the loss-of-function ABCA1 gene are often accompanied by decreased expression of ABCA1 and an increased risk of cardiovascular diseases. We summarized the ABCA1 transcription regulation mechanism, mutations, post-translational modifications, and their roles in the development of dyslipidemia, atherosclerosis, ischemia/reperfusion, myocardial infarction, and coronary heart disease.

The Roles of Fatty Acids and Apolipoproteins in the Kidneys

The kidneys are organs that require energy from the metabolism of fatty acids and glucose; several studies have shown that the kidneys are metabolically active tissues with an estimated energy requirement similar to that of the heart. The kidneys may regulate the normal and pathological function of circulating lipids in the body, and their glomerular filtration barrier prevents large molecules or large lipoprotein particles from being filtered into pre-urine. Given the permeable nature of the kidneys, renal lipid metabolism plays an important role in affecting the rest of the body and the kidneys. Lipid metabolism in the kidneys is important because of the exchange of free fatty acids and apolipoproteins from the peripheral circulation. Apolipoproteins have important roles in the transport and metabolism of lipids within the glomeruli and renal tubules. Indeed, evidence indicates that apolipoproteins have multiple functions in regulating lipid import, transport, synthesis, storage, oxidation and export, and they are important for normal physiological function. Apolipoproteins are also risk factors for several renal diseases; for example, apolipoprotein L polymorphisms induce kidney diseases. Furthermore, renal apolipoprotein gene expression is substantially regulated under various physiological and disease conditions. This review is aimed at describing recent clinical and basic studies on the major roles and functions of apolipoproteins in the kidneys.

Anchoring β-CD on simvastatin-loaded rHDL for selective cholesterol crystals dissolution and enhanced anti-inflammatory effects in macrophage/foam cells

Macrophage/foam cells and cholesterol crystals (CCs) have been regarded as the central triggers of maladaptive inflammation in atherosclerotic plaque. Despite the tremendous progress of recombinant high-density lipoprotein (rHDL) serving for targeted drug delivery to alleviate inflammation in macrophage/foam cells, the active attempt to modulate/improve its CCs dissolution capacity remains poorly explored. The untreated CCs can seriously aggravate inflammation and threaten plaque stability. Based on the superb ability of β-cyclodextrin (β-CD) to bind CCs and promote cholesterol efflux, simvastatin-loaded discoidal-rHDL (ST-d-rHDL) anchored with β-CD (βCD-ST-d-rHDL) was constructed. We verified that βCD-ST-d-rHDL specifically bound and dissolved CCs extracellularly and intracellularly. Furthermore, anchoring β-CD onto the surface of ST-d-rHDL enhanced its cholesterol removal ability in RAW 264.7 cell-derived foam cells characterized by accelerated cholesterol efflux, reduced intracellular lipid deposition, and improved cell membrane fluidity/permeability. Finally, βCD-ST-d-rHDL exerted efficient drug delivery and effective anti-inflammatory effects in macrophage/foam cells. Collectively, anchoring β-CD onto the surface of ST-d-rHDL for selective CCs dissolution, accelerated cholesterol efflux, and improved drug delivery represents an effective strategy to enhance anti-inflammatory effects for the therapy of atherosclerosis.

Aldehyde dehydrogenase 2 and PARP1 interaction modulates hepatic HDL biogenesis by LXRα-mediated ABCA1 expression

HDL cholesterol (HDL-C) predicts risk of cardiovascular disease (CVD), but the factors regulating HDL are incompletely understood. Emerging data link CVD risk to decreased HDL-C in 8% of the world population and 40% of East Asians who carry an SNP of aldehyde dehydrogenase 2 (ALDH2) rs671, responsible for alcohol flushing syndrome; however, the underlying mechanisms remain unknown. We found significantly decreased HDL-C with increased hepatosteatosis in ALDH2-KO (AKO), ALDH2/LDLR-double KO (ALKO), and ALDH2 rs671-knock-in (KI) mice after consumption of a Western diet. Metabolomics identified ADP-ribose as the most significantly increased metabolites in the ALKO mouse liver. Moreover, ALDH2 interacted with poly(ADP-ribose) polymerase 1 (PARP1) and attenuated PARP1 nuclear translocation to downregulate poly(ADP-ribosyl)ation of liver X receptor α (LXRα), leading to an upregulation of ATP-binding cassette transporter A1 (ABCA1) and HDL biogenesis. Conversely, AKO or ALKO mice exhibited lower HDL-C with ABCA1 downregulation due to increased nuclear PARP1 and upregulation of LXRα poly(ADP-ribosyl)ation. Consistently, PARP1 inhibition rescued ALDH2 deficiency-induced fatty liver and elevated HDL-C in AKO mice. Interestingly, KI mouse or human liver tissues showed ABCA1 downregulation with increased nuclear PARP1 and LXRα poly(ADP-ribosyl)ation. Our study uncovered a key role of ALDH2 in HDL biogenesis through the LXRα/PARP1/ABCA1 axis, highlighting a potential therapeutic strategy in CVD.

Pathways and Mechanisms of Cellular Cholesterol Efflux-Insight From Imaging

Cholesterol is an essential molecule in cellular membranes, but too much cholesterol can be toxic. Therefore, mammalian cells have developed complex mechanisms to remove excess cholesterol. In this review article, we discuss what is known about such efflux pathways including a discussion of reverse cholesterol transport and formation of high-density lipoprotein, the function of ABC transporters and other sterol efflux proteins, and we highlight their role in human diseases. Attention is paid to the biophysical principles governing efflux of sterols from cells. We also discuss recent evidence for cholesterol efflux by the release of exosomes, microvesicles, and migrasomes. The role of the endo-lysosomal network, lipophagy, and selected lysosomal transporters, such as Niemann Pick type C proteins in cholesterol export from cells is elucidated. Since oxysterols are important regulators of cellular cholesterol efflux, their formation, trafficking, and secretion are described briefly. In addition to discussing results obtained with traditional biochemical methods, focus is on studies that use established and novel bioimaging approaches to obtain insight into cholesterol efflux pathways, including fluorescence and electron microscopy, atomic force microscopy, X-ray tomography as well as mass spectrometry imaging.

Effects of Smoking on Diabetic Nephropathy

Diabetes is a systemic metabolic disease with serious complications that cause significant stress on the healthcare system. Diabetic kidney disease is the primary cause of end stage renal disease globally and its progression is accelerated by various factors. Another major healthcare hazard is tobacco consumption and smoking has deleterious effects on renal physiology. Prominent factors are defined as sympathetic activity, atherosclerosis, oxidative stress and dyslipidemia. This review aims to enlighten the mechanism underlying the cumulative negative effect of simultaneous exposure to hyperglycemia and nicotine.

Immune Modulation as a Key Mechanism for the Protective Effects of Remote Ischemic Conditioning After Stroke

Remote ischemic conditioning (RIC), which involves a series of short cycles of ischemia in an organ remote to the brain (typically the limbs), has been shown to protect the ischemic penumbra after stroke and reduce ischemia/reperfusion (IR) injury. Although the exact mechanism by which this protective signal is transferred from the remote site to the brain remains unclear, preclinical studies suggest that the mechanisms of RIC involve a combination of circulating humoral factors and neuronal signals. An improved understanding of these mechanisms will facilitate translation to more effective treatment strategies in clinical settings. In this review, we will discuss potential protective mechanisms in the brain and cerebral vasculature associated with RIC. We will discuss a putative role of the immune system and circulating mediators of inflammation in these protective processes, including the expression of pro-and anti-inflammatory genes in peripheral immune cells that may influence the outcome. We will also review the potential role of extracellular vesicles (EVs), biological vectors capable of delivering cell-specific cargo such as proteins and miRNAs to cells, in modulating the protective effects of RIC in the brain and vasculature.

Integrative Analyses Reveal Tstd1 as a Potential Modulator of HDL Cholesterol and Mitochondrial Function in Mice

High-density lipoprotein (HDL) cholesterol levels are closely associated with human health and diseases. To identify genes modulating plasma HDL levels, we integrated HDL measurements and multi-omics data collected from diverse mouse cohorts and combined a list of systems genetics methods, including quantitative trait loci (QTL) mapping analysis, mediation analysis, transcriptome-wide association analysis (TWAS), and correlation analysis. We confirmed a significant and conserved QTL for plasma HDL on chromosome 1 and identified that Tstd1 liver transcript correlates with plasma HDL in several independent mouse cohorts, suggesting Tstd1 may be a potential modulator of plasma HDL levels. Correlation analysis using over 70 transcriptomics datasets in humans and mice revealed consistent correlations between Tstd1 and genes known to be involved in cholesterol and HDL regulation. Consistent with strong enrichment in gene sets related to cholesterol and lipoproteins in the liver, mouse strains with high Tstd1 exhibited higher plasma levels of HDL, total cholesterol and other lipid markers. GeneBridge using large-scale expression datasets identified conserved and positive associations between TSTD1/Tstd1 and mitochondrial pathways, as well as cholesterol and lipid pathways in human, mouse and rat. In summary, we identified Tstd1 as a new modulator of plasma HDL and mitochondrial function through integrative systems analyses, and proposed a new mechanism of HDL modulation and a potential therapeutic target for relevant diseases. This study highlights the value of such integrative approaches in revealing molecular mechanisms of complex traits or diseases.

Rosmarinic Acid Exhibits a Lipid-Lowering Effect by Modulating the Expression of Reverse Cholesterol Transporters and Lipid Metabolism in High-Fat Diet-Fed Mice

Hyperlipidemia is a potent risk factor for the development of cardiovascular diseases. The reverse cholesterol transport (RCT) process has been shown to alleviate hyperlipidemia and protect against cardiovascular diseases. Recently, rosmarinic acid was reported to exhibit lipid-lowering effects. However, the underlying mechanism is still unclear. This study aims to investigate whether rosmarinic acid lowers lipids by modulating the RCT process in high-fat diet (HFD)-induced hyperlipidemic C57BL/6J mice. Our results indicated that rosmarinic acid treatment significantly decreased body weight, blood glucose, and plasma total cholesterol and triglyceride levels in HFD-fed mice. Rosmarinic acid increased the expression levels of cholesterol uptake-associated receptors in liver tissues, including scavenger receptor B type 1 (SR-B1) and low-density lipoprotein receptor (LDL-R). Furthermore, rosmarinic acid treatment notably increased the expression of cholesterol excretion molecules, ATP-binding cassette G5 (ABCG5) and G8 (ABCG8) transporters, and cholesterol 7 alpha-hydroxylase A1 (CYP7A1) as well as markedly reduced cholesterol and triglyceride levels in liver tissues. In addition, rosmarinic acid facilitated fatty acid oxidation through AMP-activated protein kinase (AMPK)-mediated carnitine palmitoyltransferase 1A (CPT1A) induction. In conclusion, rosmarinic acid exhibited a lipid-lowering effect by modulating the expression of RCT-related proteins and lipid metabolism-associated molecules, confirming its potential for the prevention or treatment of hyperlipidemia-derived diseases.

Immune-based therapies in cardiovascular and metabolic diseases: past, present and future

Cardiometabolic disorders were originally thought to be driven primarily by changes in lipid metabolism that cause the accumulation of lipids in organs, thereby impairing their function. Thus, in the setting of cardiovascular disease, statins - a class of lipid-lowering drugs - have remained the frontline therapy. In the past 20 years, seminal discoveries have revealed a central role of both the innate and adaptive immune system in driving cardiometabolic disorders. As such, it is now appreciated that immune-based interventions may have an important role in reducing death and disability from cardiometabolic disorders. However, to date, there have been a limited number of clinical trials exploring this interventional strategy. Nonetheless, elegant preclinical research suggests that immune-targeted therapies can have a major impact in treating cardiometabolic disease. Here, we discuss the history and recent advancements in the use of immunotherapies to treat cardiometabolic disorders.

Intracoronary monocyte expression pattern and HDL subfractions after non-ST elevation myocardial infarction

AIMS

Coronary artery disease (CAD) is described as a range of clinical conditions including myocardial infarction (MI) and unstable angina. Lipid and apolipoprotein profiles together with the study of cholesterol deposit and efflux serve to identify novel pre and post infarct scenarios for the treatment of these patients. In (non-ST elevation myocardial infarction) NSTEMI patients, we analysed both systemic and intracoronary serum ability to accept cholesterol as well as cholesterol efflux capacity (CEC) of monocytes in terms of expression of genes involved in the reverse cholesterol transport (RCT).

METHODS AND RESULTS

While HDL-C quantity was similar between systemic and coronary arterial blood, in 21 NSTEMI patients we observed a significant reduction of the preβ-HDL fraction and the levels of Apolipoproteins AI, AII, B and E in coronary versus systemic serum. These data are complemented with the observed reduction of CEC. On the contrary, compared to systemic arterial monocytes, in coronary microenvironment of NSTEMI patients after myocardial infarction, the monocytes exhibited a higher mRNA expression of nuclear receptor LXRα and its targets ABCA1 and APOE, which drive cholesterol efflux capacity.

CONCLUSION

In this cross-sectional study we observe that in the immediate post infarction period, there is a spontaneous bona fide ligand-induced activation of the LXR driven cholesterol efflux capacity of intracoronary monocytes to overcome the reduced serum ability to accept cholesterol and to inhibit the post-infarction pro-inflammatory local microenvironment.

Use of data-independent acquisition mass spectrometry for comparative proteomics analyses of sera from pregnant women with intrahepatic cholestasis of pregnancy

We used data-independent acquisition (DIA) proteomics technology followed by ELISAs and automated biochemical analyses to identify and validate protein expression levels in Intrahepatic Cholestasis of Pregnancy (ICP) and healthy pregnant controls. We employed bioinformatics to identify metabolic processes associated with differentially expressed proteins.The expression levels of two proteins (S100-A9 and the L-lactate dehydrogenase A chain) were significantly higher in ICP patients than in controls; the areas under the receiver operating characteristic (ROC) curves (AUCs) were 0.774 and 0.828, respectively. The expression levels of two other proteins (apolipoprotein A-I and cholinesterase) were significantly lower in patients, with values of 0.900 and 0.842, respectively. Multiple logistic regression showed that a combination of the levels of the four proteins optimized the AUC (0.962), thus more reliably diagnosing ICP. The levels of all four proteins were positively associated with that of total bile acids. Bioinformatics analyses indicated that the four proteins principally affected neutrophil activation involved in the immune response, cell adhesion, lipoprotein metabolism, and the PPAR signaling pathway. SIGNIFICANCE: This preliminary work improves our understanding of changes in serum levels of protein in pregnant women with ICP. The four proteins may serve as novel noninvasive biomarkers for ICP.

Case-Control Study and Meta-Analysis of the Association Between LIPG rs9958947 SNP and Stroke Risk

The rs9958947 single nucleotide polymorphism (SNP) resides in the promoter region of the lipase G (LIPG) gene. This newly discovered SNP increases the risk of stroke in some Asian populations, including Chinese and Korean populations. Stroke is one of the top 5 leading causes of death in Malaysia, so it is of interest to investigate whether this SNP is associated with stroke risk in the Malaysian population. Therefore, this study investigates this association through a case-control study on a Malaysian population along with a comprehensive meta-analysis. Genotyping of LIPG rs9958947 SNP was performed for 241 Malaysians using real-time polymerase chain reaction, and the odds ratios (OR) with 95% confidence intervals were calculated. The meta-analysis was conducted using the software Comprehensive Meta-Analysis ver. 2.2.064. A p value less than 0.05 was considered statistically significant. We observed that the mean age of Malaysian stroke patients was less than that of stroke patients from Korea and China. The meta-analysis showed that the LIPG rs9958947 SNP was significantly associated with an increased risk of ischemic stroke in Asian populations (dominant (CC vs. CT + TT): OR = 1.45, p < 0.001; allelic (C vs. T): OR = 1.21, p = 0.001; heterozygous (CC vs. CT): OR = 1.47, p < 0.001, and homozygous (CC vs. TT): OR = 1.46, p = 0.047). However, there was no evidence to associate this SNP with stroke risk in the Malaysian population (overall CC vs. CT: OR = 1.04, CC vs. TT: OR = 1.25, CC vs. CT + TT, OR = 1.13; all p > 0.05) and blood lipid levels.

Pre- and Post-Conditioning of the Heart: An Overview of Cardioprotective Signaling Pathways

Since the discovery of ischemic pre- and post-conditioning, more than 30 years ago, the knowledge about the mechanisms and signaling pathways involved in these processes has significantly increased. In clinical practice, on the other hand, such advancement has yet to be seen. This article provides an overview of ischemic pre-, post-, remote, and pharmacological conditioning related to the heart. In addition, we reviewed the cardioprotective signaling pathways and therapeutic agents involved in the above-mentioned processes, aiming to provide a comprehensive evaluation of the advancements in the field. The advancements made over the last decades cannot be ignored and with the exponential growth in techniques and applications. The future of pre- and post-conditioning is promising.

Effect of Egyptian Leek Leaf Extract Supplementation on Productive and Economic Performance of Broilers

Antibiotic growth promoters have been used to improve growth and feed conversion in the poultry industry for a long time; however, they were banned because of several life-threatening side effects in animals, poultry, and humans. This work was carried out to investigate the effect of leek (Allium ampeloprasum var. kurrat) leaf extract (LLE) as a non-traditional growth promoter and feed additive on growth performance, carcass characteristics, serum biochemical parameters, and economic efficiency of broilers. Hubbard unsexed 1-day-old broilers (n = 250) were fed with diets supplemented with LLE for 42 days. The experimental chicks were randomly assigned to one of the five treatment groups varying in LLE quantity in diets: 0% (control), 0.05, 0.1, 0.15, and 0.2%, with five replicates per treatment (50 chicks/treatment or 10 chicks/replicate). Results showed that LLE supplementation improved (P < 0.05) different growth performance parameters. Furthermore, dietary LLE not only decreased serum total cholesterol, triglyceride, low-density lipoprotein, and glucose levels but also increased serum high-density lipoprotein level compared to the control diet. The weight percentages of dressing (P = 0.022) and liver (P = 0.041) showed a marked increase after the addition of LLE. Return, net profit, and collective efficiency measures were increased (P = 0.001) in all LLE groups compared with the control group. Broilers that fed on diets containing 0.2% LLE showed the highest growth and economic efficiency. It could be concluded that supplementation with LLE in broilers has growth-promoting effects, improved biochemical parameters, carcass quality, and promoted economic efficiency through maximizing both return and net profit.

In Vivo Screening and Antidiabetic Potential of Polyphenol Extracts from Guava Pulp, Seeds and Leaves

Simple Summary

The incidence of diabetes has risen from 151 million people in 2000 to 463 million in 2019, with 4.2 million estimated deaths in 2019, and over 700 million people will be affected with diabetes worldwide by 2045. Thus, the screening of anti-diabetic plants is inevitable in order to overcome diabetes. This study has investigated the anti-diabetic potential of polyphenol extracts from guava leaves, seeds and pulp using an albino rat model. The in vivo study has reported that polyphenols from leaves and pulp have an ability to improve diabetic parameters, such as insulin, blood glucose and triglycerides levels. The improvement in blood parameters is also an indication of these extracts that are valuable for diabetes management. The findings of this study reveal that polyphenols from guava leaves, pulp and seeds can be used for drug development.

Abstract

The present study investigates the antidiabetic potential of polyphenol extracts purified from guava pulp, seeds and leaves using an in vivo experiment on albino rats. The polyphenols from guava pulp, seeds and leaves were extracted using methanol solvent and the sonication method while being evaluated by total phenolic contents and radical scavenging activity assay. The proximate composition of powders revealed that ash, protein and total sugars were significantly (p < 0.05) higher in leaves and seeds, while vitamin C was highest in pulp. Total phenolic and antioxidant activities were highest in pulp followed by leaves and seeds. The findings of feed intake and body gain revealed that the supplementation of polyphenols, especially from pulp, significantly (p < 0.05) increased the feed intake, which resulted in increased body weight. Moreover, total cholesterol (TC) and low-density lipoprotein (LDL) levels were significantly (p < 0.05) decreased, while the level of high-density lipoprotein (HDL) was increased in groups fed with polyphenols from guava pulp compared to both (+ive and –ive) control groups. Furthermore, blood glucose and triglycerides were significantly (p < 0.05) decreased in supplemented groups compared to the control group of diabetes mice, which resulted in the inhibition of α-amylase and glucose transport. Besides this, packed cell volume (PCV), mean corpuscular volume (MCV), hemoglobin, red blood cells (RBCs), white blood cells (WBCs) and platelet levels were increased significantly (p < 0.05) in pulp’s extract followed by leaves and seeds compared to both control groups. Overall, the antidiabetic potential of different extracts was in the following order: pulp > leaves > seeds. The findings suggest the feasibility of adding 200–250 mg/kg.bw of polyphenol extracts of pulp as an alternative to diabetic drugs.

2D QSAR studies on a series of (4S,5R)-5-[3,5-bis(trifluoromethyl)phenyl]-4-methyl-1,3-oxazolidin-2-one as CETP inhibitors

Cardiovascular disease (CVD) is one of the major causes of human death. Preliminary evidence indicates that the inhibition treatment of Cholesteryl Ester Transfer Protein (CETP) causes the most pronounced increase in HDL cholesterol reported so far. Merck has disclosed certain (4S,5R)-5-[3,5-bis(trifluoromethyl)phenyl]-4-methyl-1,3-oxazolidin-2-one derivatives, which show potent CETP inhibitory activity. Therefore, it would be desirable to develop computational models to facilitate the screening of these inhibitors. In the present work, quantitative structure-activity relationship (QSAR) models have been developed to predict the therapeutic potency of 108 derivatives of (4S,5R)-5-[3,5-bis(trifluoromethyl)phenyl]-4-methyl-1,3-oxazolidin-2-one: Multiple Linear Regression (MLR), Support Vector Regression (SVR) and Feedforward Neural Network using Particle Swarm Optimization (FNN-PSO). Six descriptors were selected using genetic algorithms, whereas, internal and external validation of the models was performed according to all available validation strategies. It was shown that CETP inhibitory activity is mainly governed by electronegativity, the structure of the molecule, and the electronic properties. The best results were obtained with the SVR model. The results obtained may assist in the design of new CETP inhibitors.

Macrophage subsets in atherosclerosis as defined by single-cell technologies

Macrophages play a major role in the pathogenesis of atherosclerosis. Many studies have shone light on the different phenotypes and functions that macrophages can acquire upon exposure to local cues. The microenvironment of the atherosclerotic plaque contains a plethora of macrophage-controlling factors, such as cytokines, oxidised low-density lipoproteins and cell debris. Previous research has determined macrophage function within the plaque mainly by using immunohistochemistry and bulk analysis. The recent development and rapid progress of single-cell technologies, such as cytometry by time of flight and single-cell RNA sequencing, now enable comprehensive mapping of the wide range of cell types and their phenotypes present in atherosclerotic plaques. In this review we discuss recent advances applying these technologies in defining macrophage subsets residing in the atherosclerotic arterial wall of mice and men. Resulting from these studies, we describe three main macrophage subsets: resident-like, pro-inflammatory and anti-inflammatory foamy TREM2hi macrophages, which are found in both mouse and human atherosclerotic plaques. Furthermore, we discuss macrophage subset-specific markers and functions. More insights into the characteristics and phenotype of immune cells within the atherosclerotic plaque may guide future clinical approaches to treat disease. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Lower than average HDL cholesterol efflux capacity in Lithuanian population

Background

The aim of our study was to evaluate high-density lipoprotein cholesterol (HDL-C) efflux capacity in healthy controls and patients with severe dyslipidemia. Evaluation of HDL function may be beneficial for better understanding of cardiovascular diseases, as well as for taking actions to minimize residual cardiovascular risk.

Methods

During 2016–2017 a total of 93 participants – 48 (51.6%) women and 45 (48.4%) men – were included in this cross-sectional study. Data of 45 (48.4%) participants with severe dyslipidemia (SD) and 48 (51.6%) controls without dyslipidemia was used for statistical analysis. Total lipid panel, concentration of lipoprotein (a) and apolipoproteins were measured, data about cardiovascular risk factors were collected and detailed evaluation of HDL-C quality was performed for all patients.

Results

Increased HDL-C concentration was associated with higher ApoA1 (r = 0.866 in controls, r = 0.63 in SD group), ApoA2 (r = 0.41 in controls, r = 0.418 in SD group) and LDL-C concentrations (r = − 0.412 in SD group), lower ApoE (r = − 0.314 in SD group) and TG concentrations (r = − 0.38 in controls, r = − 0.608 in SD group), lower ApoB/ApoA1 ratio (r = − 0.567 in control group), below average HDL-C efflux capacity (r = − 0.335 in SD group), lower BMI (r = − 0.327 in controls, r = − 0.531 in SD group) and abdominal circumference (r = − 0.309 in women with SD). Below-average HDL-C efflux capacity was found in 67.7% (N = 63) of participants. It was more often found among patients with normal weight or BMI 30–31 kg/m2. HDL-C efflux capacity was inversely associated with HDL-C concentration (r = − 0.228).

Conclusion

Abnormal HDL function may be associated with residual cardiovascular risk in Lithuanian population.

Steering the Lipid Transfer To Unravel the Mechanism of Cholesteryl Ester Transfer Protein Inhibition

Human plasma cholesteryl ester transfer protein (CETP) mediates the transfer of neutral lipids from antiatherogenic high-density lipoproteins (HDLs) to proatherogenic low-density lipoproteins (LDLs). Recent cryo-electron microscopy studies have suggested that CETP penetrates its N- and C-terminal domains in HDL and LDL to form a ternary complex, which facilitates the lipid transfer between different lipoproteins. Inhibition of CETP lipid transfer activity has been shown to increase the plasma HDL-C levels and, therefore, became an effective strategy for combating cardiovascular diseases. Thus, understanding the molecular mechanism of inhibition of lipid transfer through CETP is of paramount importance. Recently reported inhibitors, torcetrapib and anacetrapib, exhibited low potency in addition to severe side effects, which essentially demanded a thorough knowledge of the inhibition mechanism. Here, we employ steered molecular dynamics simulations to understand how inhibitors interfere with the neutral lipid transfer mechanism of CETP. Our study revealed that inhibitors physically occlude the tunnel posing a high energy barrier for lipid transfer. In addition, inhibitors bring about the conformational changes in CETP that hamper CE passage and expose protein residues that disrupt the optimal hydrophobicity of the CE transfer path. The atomic level details presented here could accelerate the designing of safe and efficacious CETP inhibitors.

Artificial High Density Lipoprotein Nanoparticles in Cardiovascular Research

Lipoproteins are endogenous nanoparticles which are the major transporter of fats and cholesterol in the human body. They play a key role in the regulatory mechanisms of cardiovascular events. Lipoproteins can be modified and manipulated to act as drug delivery systems or nanocarriers for contrast agents. In particular, high density lipoproteins (HDL), which are the smallest class of lipoproteins, can be synthetically engineered either as nascent HDL nanodiscs or spherical HDL nanoparticles. Reconstituted HDL (rHDL) particles are formed by self-assembly of various lipids and apolipoprotein AI (apo-AI). A variety of substances including drugs, nucleic acids, signal emitting molecules, or dyes can be loaded, making them efficient nanocarriers for therapeutic applications or medical diagnostics. This review provides an overview about synthesis techniques, physicochemical properties of rHDL nanoparticles, and structural determinants for rHDL function. We discuss recent developments utilizing either apo-AI or apo-AI mimetic peptides for the design of pharmaceutical rHDL formulations. Advantages, limitations, challenges, and prospects for clinical translation are evaluated with a special focus on promising strategies for the treatment and diagnosis of atherosclerosis and cardiovascular diseases.

Design and development of novel therapeutics for coronary heart disease treatment based on cholesteryl ester transfer protein inhibition - in silico approach

Cholesteryl ester transfer protein (CETP) belongs to the group of enzymes which inhibition have the application in the treatment of cardiovascular diseases. This study presents QSAR modeling for a set of compounds acting as CETP inhibitors based on the Monte Carlo optimization with SMILES notation and molecular graph-based descriptors, and field-based 3D modeling. A 3D QSAR model was developed for one random split into the training and test sets, whereas conformation independent QSAR models were developed for three random splits, with the results suggesting there is an excellent correlation between them. Various statistical approaches were used to assess the statistical quality of the developed models, including robustness and predictability, and the obtained results were very good. This study used a novel statistical metric known as the index of ideality of correlation for the final assessment of the model, and the results that were obtained suggested that the model was good. Also, molecular fragments which account for the increases and/or decreases of a studied activity were defined and then used for the computer-aided design of new compounds as potential CETP inhibitors. The final assessment of the developed QSAR model and designed inhibitors was done using molecular docking, which revealed an excellent correlation with the results from QSAR modeling.Communicated by Ramaswamy H. Sarma.

Omega-3 Fatty Acid Based Nanolipid Formulation of Atorvastatin for Treating Hyperlipidemia

Purpose: In the current study, attempts have been made to formulate an omega-3 fatty acid based nanostructured lipid carriers of atorvastatin (AT), for treating hyperlipidemia; and to evaluate their antihyperlipidemic activity using in vitro and in vivo studies. Methods: Omega-3 fatty acid based AT-loaded nanolipid carriers (NLC) were formulated by the melt emulsification ultrasonication technology. The prepared NLC consist of stearic acid (as solid lipid), omega-3 fatty acid (as liquid lipid), Tween 80, poloxamer 188 (surfactants) and soya-lecithin (co-surfactant). Results: AT loaded NLCs have a particle size of 74.76 ± 4.266 nm, a zeta potential value of -36.03 ± 1.504 mV and a high drug entrapment efficiency (EE) of 86.70 % ± 0.155. The release of AT from NLCs exhibited a sustained behaviour, which made it an ideal vehicle for drug delivery. MTT assay results indicated that NLCs are compatible with L929 (mouse fibroblast) cell lines. Anti-hyperlipidemic study showed a significant reduction in LDL and TG levels in serum with the orally administered Omega-3 fatty acid based AT loaded NLCs when compared to marketed formulation. Conclusion: The results demonstrated that the omega-3 fatty acid based NLC has the potential to be a promising nanomedicine for the treatment of hyperlipidemia.

Characterization of Lipid-Protein Interactions and Lipid-Mediated Modulation of Membrane Protein Function through Molecular Simulation

The cellular membrane constitutes one of the most fundamental compartments of a living cell, where key processes such as selective transport of material and exchange of information between the cell and its environment are mediated by proteins that are closely associated with the membrane. The heterogeneity of lipid composition of biological membranes and the effect of lipid molecules on the structure, dynamics, and function of membrane proteins are now widely recognized. Characterization of these functionally important lipid-protein interactions with experimental techniques is however still prohibitively challenging. Molecular dynamics (MD) simulations offer a powerful complementary approach with sufficient temporal and spatial resolutions to gain atomic-level structural information and energetics on lipid-protein interactions. In this review, we aim to provide a broad survey of MD simulations focusing on exploring lipid-protein interactions and characterizing lipid-modulated protein structure and dynamics that have been successful in providing novel insight into the mechanism of membrane protein function.

Dyslipidemia induced inflammatory status, platelet activation and endothelial dysfunction in rabbits: Protective role of 10-Dehydrogingerdione

10-Dehydrogingerdione is a novel cholesteryl ester transfer protein (CETP) inhibitor of natural origin. Some synthetic CETP inhibitors have recently been reported to suppress proprotein convertase subtilisin/kexin type 9 (PCSK9). Therefore, the present study aimed mainly to clarify the effect of 10-Dehydrogingerdione on cellular adhesion inflammatory molecules, platelet activation and endothelial dysfunction markers in addition to PCSK9 as compared to atorvastatin in dyslipidemic rabbits. Dyslipidemia was induced in 30 male rabbits, distributed in 3 equal groups through feeding dietary cholesterol (0.5% w/w) for 3 months. Two dyslipidemic groups were concurrently treated with either atorvastatin or 10-Dehydrogingerdione (10 mg/kg/ day, p.o) and dietary cholesterol. One additional group including 10 normal rabbits fed normal diet served as normal control (NC) group. Both 10-Dehydrogingerdione and atorvastatin significantly reduced serum CETP level and activity as well as PCSK9 and low density lipoprotein cholesterol (LDL-C) levels but increased high density lipoprotein cholesterol (HDL-C) levels as compared to dyslipidemic control (DC) rabbits (p <  0.001). Both treatments also induced a marked decrease in the interferon-gamma (IFN-γ), soluble CD40 ligand (sCD40L) and soluble P-selectin (sP-selectin) levels, inflammatory cell infiltration, as well as atherogenic and coronary risk indexes in addition to aortic atheromatous changes and intima/media ratio, respectively as compared to the DC group (p <  0.001). The reduction in these markers showed a significant correlation with PCSK9 suppression and CETP inhibitory effect. Interestingly, 10-Dehydrogingerdione exerted a greater ameliorative potential regarding these biomarkers than atorvastatin. Our findings suggest that 10-Dehydrogingerdione is a promising PCSK9 inhibitor with a significant protective value against many atherosclerotic risk factors.

ApoA-1 accelerates regeneration of small-for-size fatty liver graft after transplantation

OBJECTIVES

Apolipoprotein A-1 (ApoA-1) is involved in regulating both lipid and energy metabolism, which may play important roles in liver regeneration, especially for the liver with steatosis. We here intended to investigate the role of ApoA-1 in regeneration of small-for-size fatty liver graft and to explore the underlying mechanism.

METHODS

The association of ApoA-1 expression with liver regeneration was studied in rat liver transplantation models using small-for-size normal graft or small-for-size fatty graft. The direct role of ApoA-1 in liver regeneration was studied in mouse hepatectomy model in vivo and hepatocytes in vitro.

RESULTS

Compared to small-for-size normal graft, decreased expression of ApoA-1 associated with delayed regeneration were detected in small-for-size fatty liver graft after transplantation. In functional study, the expression of ApoA-1 was decreased in hepatocytes with steatosis and was inversely associated with the concentration of oleic acid. The ApoA-1 administration effectively attenuated hepatocytes steatosis and accelerated hepatocytes proliferation. In mouse model, ApoA-1 treatment promoted liver regeneration at day 2 after major hepatectomy. In addition, the treatment of ApoA-1 increased the expressions of PGC-1α and its target genes Tfam, Ucp2 and SDHB.

CONCLUSIONS

ApoA-1 may accelerate regeneration of small-for-size fatty liver graft at day 2 after transplantation through regulating mitochondrial function. ApoA-1 may be the potential new therapy of promoting liver regeneration.

Specific Cholesterol Binding Drives Drastic Structural Alterations in Apolipoprotein A1

Proteins typically adopt a multitude of flexible and rapidly interconverting conformers, many of which are governed by specific protein interaction domains. Whereas disc-shaped oligomeric HDL and its major protein component ApoA1 have been the focus of several investigations, the structural properties of monomeric ApoA1 remain poorly understood. Using tens of independent molecular simulations (>50 μs), we reveal that ApoA1 adopts a compact conformation. Upon the addition of a physiological concentration of cholesterol to ApoA1, the monomeric protein spontaneously formed a circular conformation. Remarkably, these drastic structural perturbations are driven by a specific cholesterol binding site at the C-terminal and a novel cholesterol binding site at the N-terminal. We propose a mechanism whereby ApoA1 opens in a stagewise manner and mutating the N-terminal binding site destroys the open "belt-shaped" topology. Complementary experiments confirm that the structural changes are induced by specific association of cholesterol with ApoA1, not by the nonspecific hydrophobic effect.

Sonodynamic therapy-induced foam cells apoptosis activates the phagocytic PPARγ-LXRα-ABCA1/ABCG1 pathway and promotes cholesterol efflux in advanced plaque

In advanced atherosclerotic plaques, defective efferocytosis of apoptotic foam cells and decreased cholesterol efflux contribute to lesion progression. In our previous study, we demonstrated that 5-aminolevulinic acid (ALA)-mediated sonodynamic therapy (SDT) could induce foam cells apoptosis via the mitochondrial-caspase pathway. In the current research, we sought to explore ALA-SDT-induced apoptosis of phagocytes and the effects of cholesterol efflux and efferocytosis in advanced apoE^-/- mice plaque.

Methods: apoE^-/- mice fed western diet were treated with ALA-SDT and sacrificed at day 1, day 3, day 7 and day 28 post treatment. THP-1 macrophage-derived foam cells were treated with ALA-SDT. 5 hours later, the supernatant was collected and added to fresh foam cells (phagocytes). Then, the lipid area, efferocytosis, cholesterol efflux, anti-inflammatory reactions and PPARγ-LXRα-ABCA1/ABCG1 pathway were detected in plaque in vivo and in phagocytes in vitro.

Results: We found that ALA-SDT induced foam cells apoptosis coupled with efferocytosis and upregulation of Mer tyrosine kinase (MerTK) both in vivo and in vitro. The lipid content in plaque decreased as early as 1 day after ALA-SDT and this tendency persisted until 28 days. The enhancement of phagocytes cholesterol efflux was accompanied by an approximately 40% decrease in free cholesterol and a 24% decrease in total cholesterol in vitro. More importantly, anti-inflammatory factors such as TGFβ and IL-10 were upregulated by ALA-SDT treatment. Finally, we found that PPARγ-LXRα-ABCA1/ABCG1 pathway was activated both in vivo and in vitro by ALA-SDT, which could be blocked by PPARγ siRNA.

Conclusions: Activation of PPARγ-LXRα-ABCA1/ABCG1 pathway induced by ALA-SDT treatment engages a virtuous cycle that enhances efferocytosis, cholesterol efflux and anti-inflammatory reactions in advanced plaque in vivo and in phagocytes in vitro.

MicroRNAs: Novel Molecular Targets and Response Modulators of Statin Therapy

Cardiovascular disease (CVD) is a major cause of death globally. Addressing cardiovascular risk factors, particularly dyslipidemia, represents the most robust clinical strategy towards reducing the CVD burden. Statins inhibit 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase and represent the main therapeutic approach for lowering cholesterol and reducing plaque formation/rupture. The protective effects of statins extend beyond lowering cholesterol. MicroRNAs (miRNAs or miRs), small noncoding regulatory RNAs, likely mediate the positive pleiotropic effects of statins via modulation of lipid metabolism, enhancement of endothelial function, inhibition of inflammation, improvement of plaque stability, and immune regulation. miRNAs are implicated in statin-related interindividual variations in therapeutic response, directly via HMG-CoA reductase, or indirectly through targeting cytochrome P450 3A (CYP3A) functionality and proprotein convertase subtilisin/kexin type9 (PCSK9) biology.

Lack of Correlation of Plasma HDL With Fecal Cholesterol and Plasma Cholesterol Efflux Capacity Suggests Importance of HDL Functionality in Attenuation of Atherosclerosis

A number of clinical findings suggested HDL-raising as a plausible approach to treat residual risk of CVD. However, lack of CVD risk reduction by elevated HDL cholesterol (HDL-C) through cholesterol ester transfer protein (CETP) inhibition and enhanced risk reduction in apolipoprotein A-I Milano (apoAI-M) individuals with low HDL-C shifted the focus from HDL-C level to HDL function. In the present study, we investigated correlations between HDL-C, HDL function, fecal cholesterol excretion, and ex vivo plasma cholesterol efflux capacity (CEC) in animal models using two HDL modulators, LXR and PPAR-α agonists. In C57Bl mice, LXR agonist, T1317, raised HDL-C by 30%, while PPAR-α agonist, fenofibrate, reduced HDL-C by 30%, but fecal cholesterol showed twofold increase in both cases. CEC showed a 30–40% increase. Combination of LXR and PPAR-α agonists showed no changes in HDL-C, but, interestingly, fecal cholesterol increased by 4.5-fold, and CEC by 40%, suggesting existence of additional pathway for fecal cholesterol excretion. Regression analysis showed a lack of correlation between HDL-C and fecal cholesterol and CEC, while fecal cholesterol showed significant correlation with CEC, a measure of HDL function. ABCA1 and G1, the two important players in RCT showed greater induction with LXR agonist than PPAR-α agonist. HDL-C increased by 40 and 80% in LXR and PPAR-α treated apoA-I transgenic mice, respectively, with 80% increase in fecal cholesterol. A fivefold increase in fecal cholesterol with no correlation with either plasma HDL-C or CEC following co-treatment with LXR and PPAR-α agonists suggested existence of an HDL-independent pathway for body cholesterol elimination. In hyperlipidemic diabetic ob/ob mice also combination of LXR and PPAR-α agonists showed marked increases in fecal cholesterol content (10–20-fold), while HDL-C rise was only 40%, further suggesting HDL-independent elimination of body cholesterol in mice treated with combination of LXR and PPAR-α agonists. Atherosclerosis attenuation by LXR and PPAR-α agonists in LDLr-deficient mice was associated with increased fecal cholesterol, but not HDL-C. However, fecal cholesterol counts showed inverse correlation with aortic cholesteryl ester content. These data suggest: (a) lack of correlation between HDL-C and fecal or aortic cholesterol content; (b) HDL function (CEC) correlated with fecal cholesterol content; (c) association of reduced aortic lipids in LDLr^−/− mice with increased fecal cholesterol, but not with HDL-C, and (d) existence of an HDL-independent pathway for fecal cholesterol excretion following co-treatment with LXR and PPAR-α agonists.

Circulating low density lipoprotein (LDL)

Low-density lipoprotein (LDL) particles are known as atherogenic agents in coronary artery diseases. They modify to other electronegative forms and may be the subject for improvement of inflammatory events in vessel subendothelial spaces. The circulating LDL value is associated with the plasma PCSK-9 level. They internalize into macrophages using the lysosomal receptor-mediated pathways. LDL uptake is related to the membrane scavenger receptors, modifications of lipid and protein components of LDL particles, vesicular maturation and lipid stores of cells. Furthermore, LDL vesicular trafficking is involved with the function of some proteins such as Rab and Lamp families. These proteins also help in the transportation of free cholesterol from lysosome into the cytosol. The aggregation of lipids in the cytosol is a starting point for the formation of foam cells so that they may participate in the primary core of atherosclerosis plaques. The effects of macrophage subclasses are different in the formation and remodeling of plaques. This review is focused on the cellular and molecular events involved in cholesterol homeostasis.

Non-coding RNAs in lipid metabolism

Cardiovascular disease (CVD), the leading cause of death and morbidity in the Western world, begins with lipid accumulation in the arterial wall, which is the initial step in atherogenesis. Alterations in lipid metabolism result in increased risk of cardiometabolic disorders, and treatment of lipid disorders remains the most common strategy aimed at reducing the incidence of CVD. Work done over the past decade has identified numerous classes of non-coding RNA molecules including microRNAs (miRNAs) and long-non-coding RNAs (lncRNAs) as critical regulators of gene expression involved in lipid metabolism and CVD, mostly acting at post-transcriptional level. A number of miRNAs, including miR-33, miR-122 and miR-148a, have been demonstrated to play important role in controlling the risk of CVD through regulation of cholesterol homeostasis and lipoprotein metabolism. lncRNAs are recently emerging as important regulators of lipid and lipoprotein metabolism. However, much additional work will be required to fully understand the impact of lncRNAs on CVD and lipid metabolism, due to the high abundance of lncRNAs and the poor-genetic conservation between species. This article reviews the role of miRNAs and lncRNAs in lipid and lipoprotein metabolism and their potential implications for the treatment of CVD.

Apolipoprotein AI prevents regulatory to follicular helper T cell switching during atherosclerosis

Regulatory T (Treg) cells contribute to the anti-inflammatory response during atherogenesis. Here we show that during atherogenesis Treg cells lose Foxp3 expression and their immunosuppressive function, leading to the conversion of a fraction of these cells into T follicular helper (Tfh) cells. We show that Tfh cells are pro-atherogenic and that their depletion reduces atherosclerosis. Mechanistically, the conversion of Treg cells to Tfh cells correlates with reduced expression of IL-2Rα and pSTAT5 levels and increased expression of IL-6Rα. In vitro, incubation of naive T cells with oxLDL prevents their differentiation into Treg cells. Furthermore, injection of lipid-free Apolipoprotein AI (ApoAI) into ApoE^−/− mice reduces intracellular cholesterol levels in Treg cells and prevents their conversion into Tfh cells. Together our results suggest that ApoAI, the main protein in high-density lipoprotein particles, modulates the cellular fate of Treg cells and thus influences the immune response during atherosclerosis.

Regulatory T (Treg) cells contribute to the anti-inflammatory response during atherogenesis. Here Gaddis et al. show that Apolipoprotein AI prevents the conversion of Treg cells into pro-atherogenic T follicular helper cells, and thus regulates the immune response during atherogenesis.