Single Ascending Dose Study of a Short Interfering RNA Targeting Lipoprotein(a) Production in Individuals With Elevated Plasma Lipoprotein(a) Levels.

Importance: Lipoprotein(a) (Lp[a]) is an important risk factor for atherothrombotic cardiovascular disease and aortic stenosis, for which there are no treatments approved by regulatory authorities. Objectives: To assess adverse events and tolerability of a short interfering RNA (siRNA) designed to reduce hepatic production of apolipoprotein(a) and to assess associated changes in plasma concentrations of Lp(a) at different doses. Design, Setting, and Participants: A single ascending dose study of SLN360, an siRNA targeting apolipoprotein(a) synthesis conducted at 5 clinical research unit sites located in the US, United Kingdom, and Australia. The study enrolled adults with Lp(a) plasma concentrations of 150 nmol/L or greater at screening and no known clinically overt cardiovascular disease. Participants were enrolled between November 18, 2020, and July 21, 2021, with last follow-up on December 29, 2021. Interventions: Participants were randomized to receive placebo (n = 8) or single doses of SLN360 at 30 mg (n = 6), 100 mg (n = 6), 300 mg (n = 6), or 600 mg (n = 6), administered subcutaneously. Main Outcomes and Measures: The primary outcome was evaluation of safety and tolerability. Secondary outcomes included change in plasma concentrations of Lp(a) to a maximum follow-up of 150 days. Results: Among 32 participants who were randomized and received the study intervention (mean age, 50 [SD, 13.5] years; 17 women [53%]), 32 (100%) completed the trial. One participant experienced 2 serious adverse event episodes: admission to the hospital for headache following SARS-CoV-2 vaccination and later for complications of cholecystitis, both of which were judged to be unrelated to study drug. Median baseline Lp(a) concentrations were as follows: placebo, 238 (IQR, 203-308) nmol/L; 30-mg SLN360, 171 (IQR, 142-219) nmol/L; 100-mg SLN360, 217 (IQR, 202-274) nmol/L; 300-mg SLN360, 285 (IQR, 195-338) nmol/L; and 600-mg SLN360, 231 (IQR, 179-276) nmol/L. Maximal median changes in Lp(a) were -20 (IQR, -61 to 3) nmol/L, -89 (IQR, -119 to -61) nmol/L, -185 (IQR, -226 to -163) nmol/L, -268 (IQR, -292 to -189) nmol/L, and -227 (IQR, -270 to -174) nmol/L, with maximal median percentage changes of -10% (IQR, -16% to 1%), -46% (IQR, -64% to -40%), -86% (IQR, -92% to -82%), -96% (IQR, -98% to -89%), and -98% (IQR, -98% to -97%), for the placebo group and the 30-mg, 100-mg, 300-mg, and 600-mg SLN360 groups, respectively. The duration of Lp(a) lowering was dose dependent, persisting for at least 150 days after administration. Conclusions and Relevance: In this phase 1 study of 32 participants with elevated Lp(a) levels and no known cardiovascular disease, the siRNA SLN360 was well tolerated, and a dose-dependent lowering of plasma Lp(a) concentrations was observed. The findings support further study to determine the safety and efficacy of this siRNA. Trial Registration: ClinicalTrials.gov Identifier: NCT04606602; EudraCT Identifier: 2020-002471-35.

Hypoglycemic and hypolipidemic effects of rutin on hyperglycemic rats.

OBJECTIVE: To study the effects of rutin on serum glucose and lipid levels in hyperglycemic rats. METHODS: Male Wistar rats were subjected to intraperitoneal streptozotocin injections and a high-sugar, high-fat diet to establish a hyperglycemic and hyperlipidemic model. The model was considered to be successfully established in rats with fasting blood sugar (FBS) ≥ 11.1 mmol/L. The study included 6 groups with 10 rats each: a blank control group, a model group, a metformin group, and groups on large, medium and small doses of rutin. The groups received intraperitoneal streptozotocin or normal saline for 21 d. FBS, serum lipids, serum insulin, insulin sensitivity index (ISI), and levels of catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and malondialdehyde (MDA) levels were evaluated in all rats. Pancreatic tissue samples were harvested to observe structural changes in islet cells. RESULTS: Large, medium, and small doses of rutin were associated with significantly reduced FBS (P < 0.05), and increased levels of ISI, CAT, GSH-Px and SOD, as well as decreased MDA (P < 0.05). Rutin administration was also related with reduced total cholesterol, triglycerides and low density lipoprotein chesterol, as well as increased high density lipoprotein chesterol (P < 0.05). Histologic evaluation revealed rutin induced repair of damaged islet cells. CONCLUSION: In diabetic rat models, rutin can significantly reduce FBS and blood lipids, improve anti-oxidant activity, increase insulin sensitivity, and induce repair of damaged islet cells.

GC × GC-MS analysis and hypolipidemic effects of polyphenol extracts from Shanxi-aged vinegar in rats under a high fat diet.

Oxidative stress, inflammation and gut microbiota disorders can be induced by long-term high-fat diets (HFD). In order to confirm that polyphenols can improve these symptoms, polyphenols from Shanxi-aged vinegar (SAVEP) were extracted, and the components were detected by Comprehensive two-dimensional gas chromatography mass spectrometry (GC × GC-MS). 41 polyphenols include 18 phenolic acids and 17 polyphenols, which have not been reported. The mechanism of SAVEP on oxidative stress and inflammatory stress induced by HFD in rats and its regulating effect on intestinal flora disorder were studied. The results showed that SAVEP could significantly improve the lipid, inflammatory stress and oxidative stress related indicators compared with the Model group ("Model" refers to the group that successfully constructed a hyperlipidemia model by feeding HFD without any drugs or SAVEP in subsequent experiments.). In addition, SAVEP decreased the Firmicutes/Bacteroidetes ratio compared with the Model group, and elevated the relative abundance of beneficial bacteria. Conclusively, SAVEP can alleviate the oxidative stress and inflammatory stress caused by HFD, improving intestinal microbial disorders. The Spearman's correlation analysis revealed that Desulfovibrio, Lactobacillus and Akkermansia were correlated negatively with all of the inflammatory indicators, whereas Ruminococcus was the opposite. These results suggest that SAVEP may be a novel strategy against oxidative stress and inflammation, restoring the normal microbial community ecology of the gut and the treatment of metabolic syndromes.

Small dense LDL - an important part of the atherogenic lipoprotein profile in individuals with impaired metabolism of lipoproteins. Comparison of two analytical procedures.

OBJECTIVES: To compare two different analytical methods for determination of small dense LDL and to determine a share of corresponding and non-corresponding (inconsistent) results METHODS: In the group of 104 hyperlipidemic patients and 20 healthy individuals of the control group we analysed the total cholesterol and triglycerides by enzymatic CHOD PAP method (Roche Diagnostics, Germany) in EDTA-K2 plasma. Small dense LDL (sdLDL) were quantified by the electrophoretic method for lipoprotein analysis on polyacrylamide gel (PAG) (Lipoprint LDL System, Quantimetrix, CA, USA) and simultaneously, the small dense LDL concentrations in the indentical samples were analysed by an enzymatic method LDL-EX ´Seiken´(Randox, England). RESULTS: In 31 patients we found the discrepancy in the sdLDL levels using the two different procedures. Out of them, 24 patients tested by enzymatic method ´SEIKEN´ had higher sdLDL values (more than 0.9 mmol/l) compared to the Lipoprint LDL results, which identified normal sdLDL values in the same samples (in 23% of tested patients). In 7 patients out of the 31 tested patients with discrepant sdLDL values, the Lipoprint LDL identified increased values of plasma sdLDL (more than 0.155 mmol/l), while the enzymatic LDL-EX Seiken did not find an increased concentration of sdLDL (in 7% of tested patients). In the control group a discrepancy in the sdLDL results between the two tested analytical methods was not found. CONCLUSION: The concentration of sdLDL in plasma lipoprotein spectrum obtained by two different laboratory procedures was analysed, compared, evaluated and 70% identical corresponding results have been confirmed.

CREBH mediates metabolic inflammation to hepatic VLDL overproduction and hyperlipoproteinemia.

Metabolic inflammation is closely associated with hyperlipidemia and cardiovascular disease. However, the underlying mechanisms are not fully understood. The current study established that cAMP-responsive-element-binding protein H (CREBH), an acute-phase transcription factor, enhances very-low-density lipoprotein (VLDL) assembly and secretion by upregulating apolipoprotein B (apoB) expression and contributes to metabolic inflammation-associated hyperlipoproteinemia induced by TNFα, lipopolysaccharides (LPS), and high-fat diet (HFD) in mice. Specifically, overexpression of CREBH significantly induced mRNA and protein expression of apoB in McA-7777 cells. Luciferase assay further revealed that the presence of CREBH could significantly increase the activity of the apoB gene promoter. In contrast, genetic depletion of CREBH in mice resulted in significant reduction in expression of hepatic apoB mRNA. Challenging mice with an acute fat load led to upregulation of triglyceride (TG)-rich lipoprotein secretion in wild type mice, but not in CREBH-null mice. TNFα treatment activated hepatic CREBH expression, which in turn enhanced hepatic apoB biosynthesis and VLDL secretion. Metabolic inflammation induced by LPS or HFD also resulted in overproduction of apoB and hyperlipoproteinemia in wild type mice, but not in CREBH-null mice. This study demonstrates that CREBH could be a mediator between metabolic inflammation and hepatic VLDL overproduction in chronic metabolic disorders. This novel finding establishes CREBH as the first transcription factor that regulates apoB expression on the transcriptional level and the subsequent VLDL biosynthesis in response to metabolic inflammation. The study also provides novel insight into the pathogenesis of hyperlipidemia in metabolic syndrome. KEY MESSAGES: CREBH mediates inflammatory signaling to VLDL overproduction in metabolic stress. Activation of CREBH in inflammation enhances mRNA and protein expression of apoB. CREBH presents a potential novel therapeutic target for hyperlipoproteinemia.

Possible involvement of PCSK9 overproduction in hyperlipoproteinemia associated with hepatocellular carcinoma: A case report.

Herein, we describe a 69-year-old Japanese man with massive type III hyperlipoproteinemia (total cholesterol, 855 mg/dL; triglyceride, 753 mg/dL) presenting as a paraneoplastic manifestation of hepatitis B virus-associated hepatocellular carcinoma. The messenger RNA expression of sterol regulatory element-binding protein-2 and proprotein convertase subtilisin/kexin 9 in the tumor tissue was increased by 13-fold and 4-fold, respectively, compared with the non-tumor tissue. Serum level of active form of PCSK9 was 382 ng/mL (reference range: 253 ± 79 ng/mL). The non-tumor tissue had extremely low expression of low-density lipoprotein receptor and low-density lipoprotein receptor-related protein 1. Together, we speculate that marked overexpression of sterol regulatory element-binding protein-2 in the tumor may stimulate the secretion of PCSK9, which inhibits the lipoprotein receptors in the non-tumor tissue, thereby causing paraneoplastic hyperlipoproteinemia.

D25V apolipoprotein C-III variant causes dominant hereditary systemic amyloidosis and confers cardiovascular protective lipoprotein profile.

Apolipoprotein C-III deficiency provides cardiovascular protection, but apolipoprotein C-III is not known to be associated with human amyloidosis. Here we report a form of amyloidosis characterized by renal insufficiency caused by a new apolipoprotein C-III variant, D25V. Despite their uremic state, the D25V-carriers exhibit low triglyceride (TG) and apolipoprotein C-III levels, and low very-low-density lipoprotein (VLDL)/high high-density lipoprotein (HDL) profile. Amyloid fibrils comprise the D25V-variant only, showing that wild-type apolipoprotein C-III does not contribute to amyloid deposition in vivo. The mutation profoundly impacts helical structure stability of D25V-variant, which is remarkably fibrillogenic under physiological conditions in vitro producing typical amyloid fibrils in its lipid-free form. D25V apolipoprotein C-III is a new human amyloidogenic protein and the first conferring cardioprotection even in the unfavourable context of renal failure, extending the evidence for an important cardiovascular protective role of apolipoprotein C-III deficiency. Thus, fibrate therapy, which reduces hepatic APOC3 transcription, may delay amyloid deposition in affected patients.

Formation of fenestrae in murine liver sinusoids depends on plasmalemma vesicle-associated protein and is required for lipoprotein passage.

Liver sinusoidal endothelial cells (LSEC) are characterized by the presence of fenestrations that are not bridged by a diaphragm. The molecular mechanisms that control the formation of the fenestrations are largely unclear. Here we report that mice, which are deficient in plasmalemma vesicle-associated protein (PLVAP), develop a distinct phenotype that is caused by the lack of sinusoidal fenestrations. Fenestrations with a diaphragm were not observed in mouse LSEC at three weeks of age, but were present during embryonic life starting from embryonic day 12.5. PLVAP was expressed in LSEC of wild-type mice, but not in that of Plvap-deficient littermates. Plvap(-/-) LSEC showed a pronounced and highly significant reduction in the number of fenestrations, a finding, which was seen both by transmission and scanning electron microscopy. The lack of fenestrations was associated with an impaired passage of macromolecules such as FITC-dextran and quantum dot nanoparticles from the sinusoidal lumen into Disse's space. Plvap-deficient mice suffered from a pronounced hyperlipoproteinemia as evidenced by milky plasma and the presence of lipid granules that occluded kidney and liver capillaries. By NMR spectroscopy of plasma, the nature of hyperlipoproteinemia was identified as massive accumulation of chylomicron remnants. Plasma levels of low density lipoproteins (LDL) were also significantly increased as were those of cholesterol and triglycerides. In contrast, plasma levels of high density lipoproteins (HDL), albumin and total protein were reduced. At around three weeks of life, Plvap-deficient livers developed extensive multivesicular steatosis, steatohepatitis, and fibrosis. PLVAP is critically required for the formation of fenestrations in LSEC. Lack of fenestrations caused by PLVAP deficiency substantially impairs the passage of chylomicron remnants between liver sinusoids and hepatocytes, and finally leads to liver damage.

Interstitial fluid lipoproteins.

PURPOSE OF REVIEW: The interstitium represents the fluid, proteins, solutes, and extracellular matrix comprising the microenvironment of tissues. We here review attempts to characterize the levels and composition of lipoproteins in human interstitial fluid, and identify potentially important questions for future research. RECENT FINDINGS: Despite the high relevance of understanding how lipoproteins enter and exit the interstitial compartment, and how they interact with extracellular and cellular molecules, scientific progress in this field has been rather slow. This is partly due to methodological difficulties, both regarding how to obtain representative samples and how to perform appropriate measurements to compare patient cohorts and to evaluate responses to treatment. Predominant techniques include peripheral lymph cannulation and suction blister creation, both of which have inherent advantages and disadvantages. Detailed studies comparing the effects of long-term incubation of serum and lymph lipoproteins are compatible with the view that HDL in interstitial fluid takes up free cholesterol from cells and transfers it into the circulation. SUMMARY: Studies of the concentration, composition, functionality, and turnover of interstitial fluid lipoproteins will be of great future interest for understanding how tissue cholesterol metabolism is regulated, and how different diseases link to increased risk for development of atherosclerosis.

Study of changes in antioxidant enzymes status in diabetic post menopausal group of women suffering from cardiovascular complications.

BACKGROUND: In type 2 diabetic patients, persistence of hyperglycemia has been reported as a cause of increased production of oxygen free radicals (FR), which leads to oxidative stress (OS) and becomes the main factor for predisposition to the cardiovascular complications in diabetes. Diabetic postmenopausal women are prone to cardiovascular disease due to reduced production of estrogen which is a potent antioxidant and prevents oxidative stress (OS) in body. The study is being aimed to find out the status of antioxidant enzymes (AOEs) and malondialdehyde (MDA) in post-menopausal diabetic women. METHODS: The study was conducted with a total of 70 cases, which included 35 Type 2 diabetic post-menopausal females (45 - 60 years) with diabetic CVD complication as the study group and 35 age matched type 2 diabetic postmenopausal females without CVD complication. RESULTS: All diabetic post menopausal females with CVD had significantly higher levels of fasting plasma glucose (FPG), postprandial plasma glucose (PPPG), total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C), catalase (CAT), and malondialdehyde (MDA) and significantly lower levels of HDL-C, reduced glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GPx), and superoxide dismutase (SOD) as compared to the levels of control subjects. CONCLUSIONS: During menopause, reduced production of estrogen causes hypertriglyceridemia, hypercholesterolemia, and hyperlipoproteinemia whose oxidation causes the accumulation of FR in the cell, which precipitates OS. Also, type 2 diabetic subjects with CVD poor glycemic control and impaired AOEs result in increased oxidative injury by failure of protective mechanisms, which further leads to oxidative stress.

[Pleiotropic effects of nicotinic acid therapy in men with coronary heart disease and elevated lipoprotein(a) levels].

PURPOSE: To assess effects of niacin on risk factors of atherosclerosis in men with coronary heart disease (CHD) and high lipoprotein(a) [Lp(a)] levels. MATERIAL AND METHODS: Sixty men (mean age 54+/-6 years) with angiographic evidence of CHD were randomized into two groups. Active group (n=30) received extended release nicotinic acid 1500 mg, control group consisted of remaining 30 patients. All patients received basic therapy with atorvastatin 10-40 mg qd. Blood samples were collected for total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C), Lp(a), lipoprotein-associated phospholipase A2 (Lp-PL-2), high-sensitivity C-reactive protein (hsCRP), complex of tissue-type plasminogen activator with plasminogen activator inhibitor type 1 (tPA/PAI-1). Carotid intima media thickness (CIMT) was measured at baseline and after 6-months therapy. RESULTS: There was no statistically significant difference between the groups in the clinical and biochemical characteristics. During the study lipid profile data were within the target levels. In the active group median percent decrease of Lp(a) level was 23% (from 84+/-40 to 67+/-25 mg/dl after 6 weeks and up to 65+/-37 mg/dl after 6 months of treatment, p<0.01); LDL-C, TG, tPA/PAI-1, and Lp-PL-2 mass levels decreased by 25, 20, 25, and 32%, respectively; HDL-C increased by 16% (p<0.05 vs baseline, respectively). Nicotinic acid treatment produced statistically significant reduction nicotinic acid of the mean CIMT (right: 0.83+/-0.16 vs 0.77+/-0.17 mm, p<0.05; left: 0.88+/-0.21 vs 0.82+/-0.17, p<0.05). In control group no changes of CIMT or blood tests were observed. CONCLUSION: In men with CHD and Lp(a) excess of addition to atorvastatin results in regression of CIMT on an average of 0.06 mm in 6 months. Such rapid and significant effect on the arterial wall structure can be attributed to the complex influence of nicotinic acid on Lp(a), lipids, Lp-PL-2 and thrombogenic factors. This is the first study providing the evidence of using Lp(a) as one of therapeutic targets in patients with high Lp(a) levels for achieving beneficial effect on a surrogate marker of atherosclerosis.

PPARdelta in humans: genetic and pharmacological evidence for a significant metabolic function.

PURPOSE OF REVIEW: Abundant data in rodents suggest an important role for peroxisomal proliferators-activated receptor-delta (PPARdelta) in regulating skeletal muscle fatty acid oxidation and this has consequences for lipid and lipoprotein metabolism. Considerably less is known in humans and this review will focus on evidence derived from studies of the PPARD gene and pharmacological use of specific PPARdelta agonists. RECENT FINDINGS: Genetic association studies of single-nucleotide polymorphisms in the PPARD gene have only provided negative or conflicting evidence for gross phenotypes such as obesity, hyperlipidaemia and type 2 diabetes. This does not exclude more subtle effects in skeletal muscle metabolic function, but studies of this type need replication. A couple of recent studies using the specific PPARdelta agonist GW501516 suggest potent hypolipidaemic actions, presumably caused by enhanced fat oxidation in skeletal muscle. SUMMARY: Considering the hypolipidaemic effect in humans by PPARdelta agonists, long-term studies are needed to confirm efficacy and safety.

Plasma lipoproteins: genetic influences and clinical implications.

Susceptibility to the growing global public health problem of cardiovascular disease is associated with levels of plasma lipids and lipoproteins. Several experimental strategies have helped us to clarify the genetic architecture of these complex traits, including classical studies of monogenic dyslipidaemias, resequencing, phenomic analysis and, more recently, genome-wide association studies and analysis of metabolic networks. The genetic basis of plasma lipoprotein levels can now be modelled as a mosaic of contributions from multiple DNA sequence variants, both rare and common, with varying effect sizes. In addition to filling gaps in our understanding of plasma lipoprotein metabolism, the recent genetic advances will improve our ability to classify, diagnose and treat dyslipidaemias.

Heparan sulphate biosynthesis and disease.

Proteoglycans carrying heparan sulphate (HS) chains are ubiquitously expressed at cell surfaces and in extra-cellular matrices, and HS chains interact with numerous proteins, including growth factors, morphogens and extra-cellular-matrix proteins. These interactions form the basis of HS-related biological phenomena. Thus, the biosynthesis of HS regulates key events in embryonic development and homeostasis, and deranged HS biosynthesis could cause diseases. EXT1 and EXT2 genes encoding the polymerase responsible for HS biosynthesis are known as causative genes of hereditary multiple exostoses, a dominantly inherited genetic disorder characterized by the formation of multiple cartilaginous tumours. In this review, we will summarize HS biosynthesis in several model animals, the effects on cellular functions by alteration of HS biosynthesis, and HS-associated diseases. This review suggests that HS biosynthetic enzymes would be potential candidates for drug targets in various diseases.

Links between enhanced fatty acid flux, protein kinase C and NFkappaB activation, and apoB-lipoprotein production in the fructose-fed hamster model of insulin resistance.

In the current study, we show evidence, in a fructose-fed hamster model of insulin resistance, that free fatty acid (FFA) can induce hepatic insulin resistance in part via PKC activation leading to increased production of atherogenic apoB100-containing lipoproteins. Interestingly, IkappaB-kinase beta (IKKbeta)-dependent NF-kappaB was activated in hepatocytes from the fructose-fed hamster as an indication for PKC activation. Treatment of hepatocytes with oleate for 16h showed the activation of the PKC isoforms, PKCalpha/betaII, in a dose dependent manner. Strikingly, the general PKC inhibitor, bisindolylmaleimide-I, Bis-I (5 microM) was found to ameliorate fructose-induced insulin resistance, restoring the phosphorylation status of PKB and suppressing apoB100 overproduction in ex vivo and in vivo. The data suggest that hepatic PKC activation, induced by increased circulating FFA may be an important factor in the development of insulin resistance and dyslipidemia seen in the fructose-fed hamster model.