scholarly journals The Novel Apolipoprotein A5 Is Present in Human Serum, Is Associated with VLDL, HDL, and Chylomicrons, and Circulates at Very Low Concentrations Compared with Other Apolipoproteins

2005 ◽  
Vol 51 (2) ◽  
pp. 351-359 ◽  
Author(s):  
Peter J O’Brien ◽  
William E Alborn ◽  
John H Sloan ◽  
Maverick Ulmer ◽  
Amechand Boodhoo ◽  
...  
Keyword(s):  
Human Serum ◽  
Particle Distribution ◽  
Sandwich Elisa ◽  
Serum Triglyceride ◽  
Mouse Serum ◽  
Peroxisome Proliferator ◽  
Serum Triglycerides ◽  
Apolipoprotein A5 ◽  
Lipoprotein Particle ◽  
First Time

Abstract Background: The recently discovered apolipoprotein A5 (ApoA5) is fast gaining attention as a key regulator of serum triglyceride concentrations. An ApoA5 mouse knock-out model produced an approximately fourfold increase in serum triglycerides, whereas a knock-in model with human ApoA5 produced 50–70% lower concentrations of mouse serum triglycerides. In addition, peroxisome proliferator-activated receptor-α agonists, which are used clinically to lower serum triglyceride concentrations, cause increased ApoA5 mRNA expression. Despite these compelling molecular biology data, relatively little is known about ApoA5 protein in human serum. Methods: To better understand circulating concentrations and lipoprotein particle distribution of ApoA5, we expressed the recombinant human ApoA5 protein and raised antibodies against both the NH2 and COOH termini. Results: Using the above reagents, we demonstrate for the first time that ApoA5 is present in human serum, although at much lower concentrations than other apolipoproteins such as ApoA1. Using a dual-antibody sandwich ELISA that we developed, we observed ApoA5 concentrations in human serum ranging from 24 to 406 μg/L compared with ∼1 g/L for ApoA1. We also examined the lipoprotein particle distribution of ApoA5 and found that ApoA5 was detectable in VLDL, HDL, and chylomicrons, but not LDL. Conclusions: These data demonstrate for the first time that ApoA5 is a secreted protein present in human serum and is associated with specific lipoprotein particles. In addition, our data indicate that the circulating concentration of human ApoA5 is very low compared with other apolipoproteins.

scholarly journals Definitive N-Terminal Protein Sequence and Further Characterization of the Novel Apolipoprotein A5 in Human Serum

2006 ◽  
Vol 52 (3) ◽  
pp. 514-517 ◽  
Author(s):  
William E Alborn ◽  
Melvin G Johnson ◽  
Melvin J Prince ◽  
Robert J Konrad
Keyword(s):  
Human Serum ◽  
Protein Sequence ◽  
Serum Triglyceride ◽  
Relative Molecular Mass ◽  
Peroxisome Proliferator ◽  
Mature Protein ◽  
Terminal Protein ◽  
Peroxisome Proliferator Activated Receptor ◽  
Apolipoprotein A5

Abstract Background: Apolipoprotein A5 (ApoA5) originally gained attention as a regulator of serum triglyceride concentrations through transgenic mouse studies. Our group recently developed the first assay to quantify serum ApoA5 protein concentrations and demonstrated that they are increased by administration of a potent peroxisome proliferator-activated receptor-α agonist. Methods: To better characterize the circulating ApoA5, the protein was purified from human serum, and a definitive N-terminal protein sequence was obtained. In light of previous observations that ApoA5 was present in VLDL and not LDL, plasma infranatant and intermediate-density lipoprotein (IDL) were analyzed for ApoA5. Because the mature protein contains a single unpaired cysteine, ApoA5 in human serum was immunoprecipitated, and its migration pattern was examined via Western blotting under reducing and nonreducing conditions to determine whether the protein circulates as a disulfide-linked homodimer or heterodimer. Results: Definitive N-terminal protein sequences obtained from ApoA5 purified from human serum indicated that cleavage of the signal peptide occurs in vivo at the predicted site. We found ApoA5 in VLDL, HDL, and chylomicrons but not in LDL, IDL, or plasma infranatant. Under both reducing and nonreducing conditions, ApoA5 migrated mainly as a single band with a relative molecular mass (Mr) of ∼39 000, indicating that the protein exists in serum as a monomer and not as a disulfide-linked homodimer or heterodimer. Conclusions: Our data help characterize ApoA5 by defining its lipoprotein particle distribution, by determining its N-terminal protein sequence, and by demonstrating that the mature protein circulates mainly as a monomer and not as a disulfide-linked homodimer or heterodimer.

scholarly journals Marked effects of novel selective peroxisome proliferator-activated receptor α modulator, pemafibrate in severe hypertriglyceridemia: preliminary report

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Chie Iitake ◽  
Daisaku Masuda ◽  
Masahiro Koseki ◽  
Shizuya Yamashita
Keyword(s):  
Acute Pancreatitis ◽  
Serum Triglyceride ◽  
High Serum ◽  
Peroxisome Proliferator ◽  
Serious Adverse Events ◽  
Serum Triglycerides ◽  
Oral Tablet ◽  
Peroxisome Proliferator Activated Receptor ◽  
Severe Hypertriglyceridemia ◽  
Potential Efficacy

Abstract Background Currently available treatments have only been partly successful in patients with severe hypertriglyceridemia, including those with high serum triglycerides above 1,000 mg/dL (11.3 mmol/L), who often suffer from acute pancreatitis. Pemafibrate is a novel selective peroxisome proliferator-activated receptor α modulator (SPPARMα) which has been developed as an affordable oral tablet in Japan. We herein report the first three patients with severe hypertriglyceridemia who were successfully treated with pemafibrate. Methods Three patients with fasting serum triglyceride (TG) levels above 1,000 mg/dL (11.3 mmol/L) were treated with pemafibrate (0.2–0.4 mg/day, 0.1–0.2 mg BID). Results Serum TGs decreased from 2,000–3,000 mg/dL (22.6–33.9 mmol/L) to < 250 mg/dL (2.8 mmol/L) without adverse effects in all three patients. Serum TGs in Patient 1 and 2 decreased from 1,326 mg/dL (15.0 mmol/L) to 164 mg/dL (1.9 mmol/L) and from 2,040 mg/dL (23.1 mmol/L) to 234 mg/dL (2.6 mmol/L), respectively. Patient 3 with type 2 diabetes and 12.1% (109 mmol/mol) hemoglobin A1c had a TG level of 2,300 mg/dL (26.0 mmol/L). Even after glycemic control improved, TG remained high. After pemafibrate administration, TG decreased to 200 mg/dL (2.3 mmol/L). All patients showed no serious adverse events. Conclusions Pemafibrate demonstrated potential efficacy and safety for severe hypertriglyceridemia which may contribute to the prevention of acute pancreatitis, in a manner that can be easily prescribed and used as an oral tablet.

Dietary isoflavone supplementation modulates lipid metabolism via PPARα-dependent and -independent mechanisms

2006 ◽  
Vol 26 (1) ◽  
pp. 8-14 ◽  
Author(s):  
Orsolya Mezei ◽  
Yilan Li ◽  
Eimear Mullen ◽  
Jennifer S. Ross-Viola ◽  
Neil F. Shay
Keyword(s):  
Gene Expression ◽  
Lipid Metabolism ◽  
Soy Protein ◽  
Knockout Mice ◽  
Estrogenic Activity ◽  
Serum Triglyceride ◽  
Peroxisome Proliferator ◽  
Wild Type ◽  
Serum Triglycerides ◽  
Regulated Gene Expression

Intake of soy protein has been associated with improvements in lipid metabolism, with much attention being focused on the serum cholesterol-lowering property of soy. The component or components of soy that are responsible for improvements in lipid metabolism have been investigated and their specific actions debated. One component, the isoflavones, has been shown to have weak estrogenic activity, and recently, several research groups have suggested that isoflavones are activating peroxisome proliferator-activated receptors (PPARs). The three different isoforms of PPARs (α, γ, and δ) have overlapping tissue distributions and functions associated with lipid metabolism. The goal of the present study was to investigate the hypothesis that the effect of isoflavones is mediated through the PPARα receptor. Male and female 129/Sv mice were obtained, including both wild-type and genetically altered PPARα knockout mice. Groups of mice were fed high-fat atherogenic diets containing soy protein +/- isoflavones and PPARα agonist fenofibrate for 6 wk. At the end of 6 wk, serum and tissue lipid levels were measured along with hepatic gene expression. Most notably, serum triglycerides were reduced by isoflavone consumption. Compared with intake of a low-isoflavone basal diet, isoflavone intake reduced serum triglyceride levels by 36 and 52% in female and male wild-type mice, respectively, compared with 55 and 52% in fenofibrate-treated mice. Isoflavones also improved serum triglyceride levels in knockout mice, whereas fenofibrate did not, suggesting that two different regulatory mechanisms may be affected by isoflavone intake. Isoflavone intake resembled action of fenofibrate on PPARα-regulated gene expression, although less robustly compared with fenofibrate. We suggest that, at the levels consumed in this study, isoflavone intake is altering lipid metabolism in a manner consistent with activation of PPARα and also via a PPARα-independent mechanism as well.

scholarly journals Differentiating iron-loading anemias using a newly developed and analytically validated ELISA for human serum erythroferrone

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254851
Author(s):  
Laura Diepeveen ◽  
Rian Roelofs ◽  
Nicolai Grebenchtchikov ◽  
Rachel van Swelm ◽  
Leon Kautz ◽  
...  
Keyword(s):  
Human Serum ◽  
Polyclonal Antibodies ◽  
Sandwich Elisa ◽  
Thalassemia Major ◽  
Diagnostic Value ◽  
Iron Availability ◽  
Analytical Validation ◽  
Serum Samples ◽  
Reliable Quantification ◽  
First Time

Erythroferrone (ERFE), the erythroid regulator of iron metabolism, inhibits hepcidin to increase iron availability for erythropoiesis. ERFE plays a pathological role during ineffective erythropoiesis as occurs in X-linked sideroblastic anemia (XLSA) and β-thalassemia. Its measurement might serve as an indicator of severity for these diseases. However, for reliable quantification of ERFE analytical characterization is indispensable to determine the assay’s limitations and define proper methodology. We developed a sandwich ELISA for human serum ERFE using polyclonal antibodies and report its extensive analytical validation. This new assay showed, for the first time, the differentiation of XLSA and β-thalassemia major patients from healthy controls (p = 0.03) and from each other (p<0.01), showing the assay provides biological plausible results. Despite poor dilution linearity, parallelism and recovery in patient serum matrix, which indicated presence of a matrix effect and/or different immunoreactivity of the antibodies to the recombinant standard and the endogenous analyte, our assay correlated well with two other existing ERFE ELISAs (both R2 = 0.83). Nevertheless, employment of one optimal dilution of all serum samples is warranted to obtain reliable results. When adequately performed, the assay can be used to further unravel the human erythropoiesis-hepcidin-iron axis in various disorders and assess the added diagnostic value of ERFE.

scholarly journals Serum Proprotein Convertase Subtilisin Kexin Type 9 Is Correlated Directly with Serum LDL Cholesterol

2007 ◽  
Vol 53 (10) ◽  
pp. 1814-1819 ◽  
Author(s):  
William E Alborn ◽  
Guoqing Cao ◽  
Holly E Careskey ◽  
Yue-Wei Qian ◽  
Danise R Subramaniam ◽  
...  
Keyword(s):  
Human Serum ◽  
Total Cholesterol ◽  
Ldl Cholesterol ◽  
Sandwich Elisa ◽  
Hdl Cholesterol ◽  
Serum Concentrations ◽  
Loss Of Function ◽  
Proprotein Convertase ◽  
Serum Samples ◽  
Lipoprotein Particle

Abstract Background: Proprotein convertase subtilisin kexin type 9 (PCSK9) is gaining attention as a key regulator of serum LDL-cholesterol (LDLC). This novel serine protease causes the degradation of hepatic LDL receptors by an unknown mechanism. In humans, gain-of-function mutations in the PCSK9 gene cause a form of familial hypercholesterolemia, whereas loss-of-function mutations result in significantly decreased LDLC and decreased cardiovascular risk. Relatively little is known about PCSK9 in human serum. Methods: We used recombinant human PCSK9 protein and 2 different anti-PCSK9 monoclonal antibodies to build a sandwich ELISA. We measured PCSK9 and lipids in 55 human serum samples and correlated the results. We used the anti-PCSK9 antibodies to assay lipoprotein particle fractions separated by sequential flotation ultracentrifugation. Results: Serum concentrations of PCSK9 ranged from 11 to 115 μg/L and were directly correlated with serum concentrations of LDLC (r = 0.45, P = 0.001) and total cholesterol (r = 0.50, P = 0.0003), but not with triglycerides (r = 0.15, P = 0.28) or HDL cholesterol concentrations (r = 0.13, P = 0.36). PCSK9 was not detectable in any lipoprotein particle fraction, including LDL. Conclusions: PCSK9 is present in human serum, likely not associated with specific lipoprotein particles. The circulating concentrations of human PCSK9 are directly correlated with LDL and total cholesterol concentrations.

No Evidence for Short-Term Regulation of Plasminogen Activator Inhibitor Activity by Insulin in Man

1992 ◽  
Vol 67 (01) ◽  
pp. 117-120 ◽  
Author(s):  
Helena Vuorinen-Markkola ◽  
llpo Puhakainen ◽  
Hannele Yki-Järvinen
Keyword(s):  
Plasminogen Activator ◽  
Plasma Glucose ◽  
Serum Triglyceride ◽  
Plasminogen Activator Inhibitor ◽  
Saline Infusion ◽  
Serum Triglycerides ◽  
Serum Free ◽  
Free Insulin ◽  
Activator Inhibitor ◽  
Pai 1

SummaryIn crossectional studies a positive correlation has been found between circulating insulin, triglycerides and plasminogen activator inhibitor (PAI-1) activity. To directly examine the effect of insulin on PAI-1 activity in vivo, we determined the response of PAI-1 activity in 17 normal subjects to acute hyperinsulinemia (serum free insulin 92 ± 8 mU/l) during maintenance of normoglycemia (plasma glucose 5.1 ± 0.1 mmol/l). In 12 matched control subjects PAI-1 activity was measured during infusion of saline (serum free insulin 3.6 ± 0.3 mU/l, plasma glucose 5.2 ± 0.1 mmol/l). Plasma PAI-1 activity decreased during the insulin infusion from 9.0 α 1.4 to 5.6 α 0.8 U/ml (p <0.01), and during saline infusion from 7.0 ± 1.4 to 4.3 ± 0.6 U/ml (p <0.05). Serum triglyceride concentrations decreased from 1.09 ± 0.20 to 0.76 ± 0.09 mmol/l (p < 0.001) during hyperinsulinemia but remained unchanged during the saline infusion (1.04 ± 0.11 vs. 1.02 ± 0.12 mmol/l, NS). We conclude that insulin does not acutely change plasma PAI-1 activity, and that acute insulin-induced changes in serum triglycerides occur independently from those of PAI-1 activity.

scholarly journals Inflammatory risk factors for hypertriglyceridemia in patients with severe influenza

2020 ◽  
Vol 48 (8) ◽  
pp. 030006052091805
Author(s):  
Tianshu Zhai ◽  
Xiaojing Wu ◽  
Nannan Zhang ◽  
Xu Huang ◽  
Qingyuan Zhan
Keyword(s):  
Risk Factors ◽  
Growth Factor ◽  
Influenza Virus Infection ◽  
Serum Triglyceride ◽  
Normal Serum ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Triglycerides ◽  
Monocyte Chemoattractant Protein 1 ◽  
Severe Influenza ◽  
Ifn Γ

Objective Inflammation and viral infections can induce significant changes in lipid metabolism. Hypertriglyceridemia (HTG) often occurs secondary to obesity, which is an independent risk factor for influenza virus infection. However, the inflammatory risk factors contributing to HTG in patients with severe influenza have yet to be elucidated. Materials and methods Plasma and bronchoalveolar lavage fluid (BALF) samples were collected from 33 patients with severe influenza (n = 26 control patients with normal serum triglyceride levels and n = 7 HTG patients with serum triglycerides >2.3 mM). Levels of 45 putative inflammatory risk factors were quantitated using a commercial enzyme-linked immunosorbent assay kit. Results Plasma levels of interferon (IFN)-γ, interleukin (IL)-18, IL-1 receptor antagonist (IL-1RA), monocyte chemoattractant protein-1, macrophage inflammatory protein-1α, hepatocyte growth factor, stem cell factor, and vascular endothelial growth factor A were significantly higher in HTG patients compared with control patients. BALF samples from HTG patients contained significantly higher levels of IL-1RA and lower levels of IFN-γ-inducible protein-10. Conclusion HTG in patients with severe influenza is associated with alterations in several inflammatory risk factors. Our results provide new insights that may enable more effective clinical management of severe influenza combined with HCT.

Hydrogen sulfide reduces serum triglyceride by activating liver autophagy via the AMPK-mTOR pathway

2015 ◽  
Vol 309 (11) ◽  
pp. E925-E935 ◽  
Author(s):  
Li Sun ◽  
Song Zhang ◽  
Chengyuan Yu ◽  
Zhenwei Pan ◽  
Yang Liu ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
High Fat Diet ◽  
Serum Triglyceride ◽  
Mtor Pathway ◽  
Autophagic Flux ◽  
High Fat ◽  
Sodium Hydrosulfide ◽  
Metabolism Inhibition ◽  
Qualitative Effect ◽  
First Time

Autophagy plays an important role in liver triglyceride (TG) metabolism. Inhibition of autophagy could reduce the clearance of TG in the liver. Hydrogen sulfide (H2S) is a potent stimulator of autophagic flux. Recent studies showed H2S is protective against hypertriglyceridemia (HTG) and noalcoholic fatty liver disease (NAFLD), while the mechanism remains to be explored. Here, we tested the hypothesis that H2S reduces serum TG level and ameliorates NAFLD by stimulating liver autophagic flux by the AMPK-mTOR pathway. The level of serum H2S in patients with HTG was lower than that of control subjects. Sodium hydrosulfide (NaHS, H2S donor) markedly reduced serum TG levels of male C57BL/6 mice fed a high-fat diet (HFD), which was abolished by coadministration of chloroquine (CQ), an inhibitor of autophagic flux. In HFD mice, administration of NaSH increased the LC3BII-to-LC3BI ratio and decreased the p62 protein level. Meanwhile, NaSH increased the phosphorylation of AMPK and thus reduced the phosphorylation of mTOR in a Western blot study. In cultured LO2 cells, high-fat treatment reduced the ratio of LC3BII to LC3BI and the phosphorylation of AMPK, which were reversed by the coadministration of NaSH. Knockdown of AMPK by siRNA in LO2 cells blocked the autophagic enhancing effects of NaSH. The same qualitative effect was observed in AMPKα2−/− mice. These results for the first time demonstrated that H2S could reduce serum TG level and ameliorate NAFLD by activating liver autophagy via the AMPK-mTOR pathway.

scholarly journals Detection of circulating antigens in serum samples of mice experimentally infected with Trichinella spiralis by a sandwich ELISA based on IgY

2014 ◽  
Vol 51 (3) ◽  
pp. 181-189 ◽  
Author(s):  
F. Jing ◽  
J. Cui ◽  
R. Liu ◽  
L. Liu ◽  
P. Jiang ◽  
...  
Keyword(s):  
Post Infection ◽  
Trichinella Spiralis ◽  
Sandwich Elisa ◽  
Egg Yolk ◽  
Mouse Serum ◽  
Serum Samples ◽  
Egg Yolk Immunoglobulin ◽  
Muscle Larvae ◽  
Sandwich Elisa Assay ◽  
Circulating Antigens

AbstractIn the present study, a sandwich ELISA based on IgY (egg yolk immunoglobulin) was developed for detection of circulating antigens (CAg) in sere of mice experimentally infected with Trichinella spiralis. The IgY-sandwich ELISA assay involved the use of chicken antibody IgY against excretory-secretory (ES) antigens of Trichinella spiralis muscle larvae as a capture antibody and mouse polyclonal antibody IgG to ES antigens as a detecting antibody. This method was able to detect as little as 3 ng/ml of ES antigens added to normal mouse serum. A group of sixteen mice was orally inoculated with 500 T. spiralis muscle larvae per animal. The serum samples from the infected mice were taken during 1–35 days post-infection (dpi). The CAg was detectable as early as 8 dpi in the sera of infected mice. The level of CAg increased dramatically during 13–15 dpi and reached a peak at 22 dpi and remained a plateau for 3 days, then declined gradually. Another peak of CAg occurred at 31 dpi. The anti-Trichinella antibodies was first detected in 14.3 % of the infected mice at 2 weeks post-infection (wpi), and reached a peak positive rate of 100 % at 5 wpi. Moreover, the infected mice were treated with abendazole at 5 wpi and the serum CAg levels increased significantly during 2–6 days posttreatment (dpt) and then declined rapidly during 8–14 dpt. By 42 dpt, the CAg levels decreased to the undetected level, but the detection rate of antibodies was still 100 %. The IgY-sandwich ELISA appears to be a sensitive for detection of antigenemia of T. spiralis and valuable to judge the efficacy of chemotherapy in trichinellosis.

Spectroscopic and molecular modeling studies of human serum albumin interaction with propyl gallate

RSC Advances ◽  
2014 ◽  
Vol 4 (110) ◽  
pp. 64559-64564 ◽  
Author(s):  
Jafar Ezzati Nazhad Dolatabadi ◽  
Vahid Panahi-Azar ◽  
Abolfazl Barzegar ◽  
Ali Akbar Jamali ◽  
Fahimeh Kheirdoosh ◽  
...  
Keyword(s):  
Molecular Modeling ◽  
Human Serum Albumin ◽  
Fluorescence Quenching ◽  
Serum Albumin ◽  
Human Serum ◽  
Propyl Gallate ◽  
Fluorescence Quenching Method ◽  
Molecular Modeling Studies ◽  
Quenching Method ◽  
First Time

For the first time, PG interaction with HSA using fluorescence quenching method, circular dichroism spectroscopy and molecular modeling was investigated.

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