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Sulu C, Dedeoglu SE, Gonen B, Hepokur M, Guzel AN, Sahin S, Demir AN, Kara Z, Konukoglu D, Damci T, Gonen MS. Serum Lipoprotein(a) Is Not Associated with Graves' Ophthalmopathy. Metab Syndr Relat Disord 2024; 22:69-76. [PMID: 37883657 DOI: 10.1089/met.2023.0162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2023] Open
Abstract
Aim: To investigate the relationship of serum lipoprotein(a) [Lp(a)] and other serum lipids with presence of Graves' ophthalmopathy (GO). Methods: A total of 99 consecutive patients diagnosed with Graves' disease (GD), aged 18-65 years, who had not received prior treatment for GO, thyroid surgery, or radioactive iodine therapy, were recruited between June 2020 and July 2022. In addition, 56 healthy controls (HCs) were included as the control group. All patients underwent an ophthalmological examination, and were classified based on the presence of GO into the GO group (n = 45) and no GO group (n = 54). Fasting blood samples were collected from all participants to analyze serum lipid parameters, including Lp(a), total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides. Results: The median serum levels of Lp(a) were 5.7 [4.3-9.2] in the GO group, 6.7 [3.7-9.9] in the no GO group, and 4.7 [3-7.6] in the HC group. The intergroup comparisons of serum Lp(a) levels showed no significant result. The serum levels of total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides were also similar between the groups (P > 0.05 for all). However, when analyzing only euthyroid GD patients and the control group, the serum LDL cholesterol levels were found to be significantly higher in the euthyroid GO group [median: 132 interquartile range (IQR) (110-148) mg/dL] than in the HCs [median: 96 IQR (94-118) mg/dL] (P = 0.002). Conclusion: The findings of our study did not support the association between serum Lp(a) levels and GO.
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Affiliation(s)
- Cem Sulu
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkiye
| | - Selin Ece Dedeoglu
- Department of Internal Medicine, Eyupsultan State Hospital, Istanbul, Turkiye
| | - Busenur Gonen
- Department of Ophthalmology, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkiye
| | - Mustafa Hepokur
- Department of Ophthalmology, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkiye
| | - Adnan Nuri Guzel
- Department of Internal Medicine, and Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkiye
| | - Serdar Sahin
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkiye
| | - Ahmet Numan Demir
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkiye
| | - Zehra Kara
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkiye
| | - Dildar Konukoglu
- Department of Biochemistry, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkiye
| | - Taner Damci
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkiye
| | - Mustafa Sait Gonen
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkiye
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Circulating lipoprotein (a) and all-cause and cause-specific mortality: a systematic review and dose-response meta-analysis. Eur J Epidemiol 2023; 38:485-499. [PMID: 36708412 PMCID: PMC10164031 DOI: 10.1007/s10654-022-00956-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 12/16/2022] [Indexed: 01/29/2023]
Abstract
AIMS To investigate the association between circulating lipoprotein(a) (Lp(a)) and risk of all-cause and cause-specific mortality in the general population and in patients with chronic diseases, and to elucidate the dose-response relations. METHODS AND RESULTS We searched literature to find prospective studies reporting adjusted risk estimates on the association of Lp(a) and mortality outcomes. Forty-three publications, reporting on 75 studies (957,253 participants), were included. The hazard ratios (HRs) and 95% confidence intervals (95%CI ) for the top versus bottom tertile of Lp(a) levels and risk of all-cause mortality were 1.09 (95%CI: 1.01-1.18, I2: 75.34%, n = 19) in the general population and 1.18 (95%CI: 1.04-1.34, I2: 52.5%, n = 12) in patients with cardiovascular diseases (CVD). The HRs for CVD mortality were 1.33 (95%CI: 1.11-1.58, I2: 82.8%, n = 31) in the general population, 1.25 (95%CI: 1.10-1.43, I2: 54.3%, n = 17) in patients with CVD and 2.53 (95%CI: 1.13-5.64, I2: 66%, n = 4) in patients with diabetes mellitus. Linear dose-response analyses revealed that each 50 mg/dL increase in Lp(a) levels was associated with 31% and 15% greater risk of CVD death in the general population and in patients with CVD. No non-linear dose-response association was observed between Lp(a) levels and risk of all-cause or CVD mortality in the general population or in patients with CVD (Pnonlinearity > 0.05). CONCLUSION This study provides further evidence that higher Lp(a) levels are associated with higher risk of all-cause mortality and CVD-death in the general population and in patients with CVD. These findings support the ESC/EAS Guidelines that recommend Lp(a) should be measured at least once in each adult person's lifetime, since our study suggests those with higher Lp(a) might also have higher risk of mortality.
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Patel N, Mittal N, Choubdar PA, Taub PR. Lipoprotein(a)—When to Screen and How to Treat. CURRENT CARDIOVASCULAR RISK REPORTS 2022. [DOI: 10.1007/s12170-022-00698-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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4
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Tognetti M, Sklodowski K, Müller S, Kamber D, Muntel J, Bruderer R, Reiter L. Biomarker Candidates for Tumors Identified from Deep-Profiled Plasma Stem Predominantly from the Low Abundant Area. J Proteome Res 2022; 21:1718-1735. [PMID: 35605973 PMCID: PMC9251764 DOI: 10.1021/acs.jproteome.2c00122] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
![]()
The plasma proteome
has the potential to enable a holistic analysis
of the health state of an individual. However, plasma biomarker discovery
is difficult due to its high dynamic range and variability. Here,
we present a novel automated analytical approach for deep plasma profiling
and applied it to a 180-sample cohort of human plasma from lung, breast,
colorectal, pancreatic, and prostate cancers. Using a controlled quantitative
experiment, we demonstrate a 257% increase in protein identification
and a 263% increase in significantly differentially abundant proteins
over neat plasma. In the cohort, we identified 2732 proteins. Using
machine learning, we discovered biomarker candidates such as STAT3
in colorectal cancer and developed models that classify the diseased
state. For pancreatic cancer, a separation by stage was achieved.
Importantly, biomarker candidates came predominantly from the low
abundance region, demonstrating the necessity to deeply profile because
they would have been missed by shallow profiling.
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Affiliation(s)
| | | | | | | | - Jan Muntel
- Biognosys, Schlieren, Zurich 8952, Switzerland
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5
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Langsted A, Nordestgaard BG. Genetics of Lipoprotein(a): Cardiovascular Disease and Future Therapy. Curr Atheroscler Rep 2021; 23:46. [PMID: 34148150 DOI: 10.1007/s11883-021-00937-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2021] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW Lipoprotein(a) levels are determined 80-90% by genetics and differ by up to 1000-fold between individuals. This review discusses the most recent literature on lipoprotein(a) as a risk factor for cardiovascular disease, as well as future lipoprotein(a)lowering therapies. RECENT FINDINGS Over the past few decades, numerous studies have observed that high lipoprotein(a) levels are associated observationally and causally through human genetics with increased risk of cardiovascular disease. Also, the development of safe and effective therapies to lower lipoprotein(a) is ongoing, most importantly using antisense oligonucleotides to prevent production of lipoprotein(a). Finally, both observational and genetic studies have estimated the extent to which lowering of lipoprotein(a) is needed to obtain a clinically meaningful reduction in the risk of cardiovascular disease. Lipoprotein(a) is a causal risk factor for cardiovascular disease; however, currently no approved safe and effective therapy is available to lower lipoprotein(a) levels. That said, promising randomized studies using antisense oligonucleotides show up to 80% reductions in lipoprotein(a), reductions that hopefully will result in lowering the risk of cardiovascular disease as presently tested in the ongoing HORIZON phase 3 trial.
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Affiliation(s)
- Anne Langsted
- Department of Clinical Biochemistry, Herlev and Gentofte Hospital, Copenhagen University Hospital, Borgmester Ib Juuls Vej 73, Entrance 7, 4th floor, N5, DK-2730, Herlev, Denmark. .,The Copenhagen General Population Study, Herlev and Gentofte Hospital, Copenhagen University Hospital, Borgmester Ib Juuls Vej 73, Entrance 7, 4th floor, N5, DK-2730, Herlev, Denmark. .,Department of Clinical Medicine Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Børge G Nordestgaard
- Department of Clinical Biochemistry, Herlev and Gentofte Hospital, Copenhagen University Hospital, Borgmester Ib Juuls Vej 73, Entrance 7, 4th floor, N5, DK-2730, Herlev, Denmark.,The Copenhagen General Population Study, Herlev and Gentofte Hospital, Copenhagen University Hospital, Borgmester Ib Juuls Vej 73, Entrance 7, 4th floor, N5, DK-2730, Herlev, Denmark.,Department of Clinical Medicine Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Pernemalm M, Sandberg A, Zhu Y, Boekel J, Tamburro D, Schwenk JM, Björk A, Wahren-Herlenius M, Åmark H, Östenson CG, Westgren M, Lehtiö J. In-depth human plasma proteome analysis captures tissue proteins and transfer of protein variants across the placenta. eLife 2019; 8:41608. [PMID: 30958262 PMCID: PMC6519984 DOI: 10.7554/elife.41608] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 04/04/2019] [Indexed: 01/03/2023] Open
Abstract
Here, we present a method for in-depth human plasma proteome analysis based on high-resolution isoelectric focusing HiRIEF LC-MS/MS, demonstrating high proteome coverage, reproducibility and the potential for liquid biopsy protein profiling. By integrating genomic sequence information to the MS-based plasma proteome analysis, we enable detection of single amino acid variants and for the first time demonstrate transfer of multiple protein variants between mother and fetus across the placenta. We further show that our method has the ability to detect both low abundance tissue-annotated proteins and phosphorylated proteins in plasma, as well as quantitate differences in plasma proteomes between the mother and the newborn as well as changes related to pregnancy. Blood cells travel through the blood vessels in a soupy mixture of proteins called plasma. Most of these proteins are plasma-specific, yet small amounts of proteins can leak into the plasma from other body parts and may provide hints about what is going on elsewhere in the body. This could allow doctors to use plasma samples to assess health or detect disease. But so far developing methods to detect these leaked proteins has proved difficult. Plasma passing through the placenta can transfer proteins between a pregnant woman and her baby. Learning more about these protein exchanges may help scientists understand how the mother and baby adapt to each other and what triggers child birth. But, so far, they have been hard to study. Using DNA to help trace the origins of proteins found in mother or baby could make it easier. Now, Pernemalm et al. have used DNA sequencing in combination with protein analysis to identify proteins passed between two pregnant mothers and their babies. Comparing the genetic sequences of each mother and child made it possible to trace the origin of the proteins. For example, if a mother had a version of the protein that matched genes the child inherited from its father, they knew it passed from the baby to the mother. This approach found 24 proteins in plasma from two pregnant mothers that had likely passed through the placenta during pregnancy. Pernemalm et al. also analyzed the plasma of 30 healthy individuals and confirmed that it contained several proteins that had likely leaked from other organs, including the lungs and pancreas. Monitoring protein transfer between pregnant mother and baby may help scientists identify what triggers normal or premature deliveries. One advantage of the technique developed Pernemalm et al. is that it can analyze plasma proteins from large numbers of people, which could enable larger studies. More refinement of the technique may also allow scientists to identify leaked proteins in the plasma that provide an early warning of cancer or other diseases.
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Affiliation(s)
- Maria Pernemalm
- Karolinska Institute, Stockholm, Sweden.,Proteogenomics, Science for Life Laboratory, Sweden
| | | | - Yafeng Zhu
- Karolinska Institute, Stockholm, Sweden.,Proteogenomics, Science for Life Laboratory, Sweden
| | - Jorrit Boekel
- Karolinska Institute, Stockholm, Sweden.,Proteogenomics, Science for Life Laboratory, Sweden
| | | | | | | | | | | | | | | | - Janne Lehtiö
- Karolinska Institute, Stockholm, Sweden.,Proteogenomics, Science for Life Laboratory, Sweden
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7
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Chen P, Zhang R, Mou L, Li X, Qin Y, Li X. An impaired hepatic clock system effects lipid metabolism in rats with nephropathy. Int J Mol Med 2018; 42:2720-2736. [PMID: 30132511 PMCID: PMC6192718 DOI: 10.3892/ijmm.2018.3833] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 08/20/2018] [Indexed: 01/22/2023] Open
Abstract
Hyperlipidemia is a key clinical feature in patients with nephrotic syndrome (NS) that is associated with the incidence of cardiovascular events. Recent studies have suggested that the disorders of triglycerides, gluconeogenesis and liver glucose metabolism are associated with the abnormal transcription of clock genes. However, changes to the circadian rhythm of blood lipids in NS require further exploration, and the effects of NS on the hepatic clock system remain to be elucidated. In the present study, the impaired diurnal rhythm of the hepatic core clock genes (BMAL1, CLOCK, CRY1, CRY2, PER1 and PER2) significantly induced circadian rhythm abnormalities in liver-specific clock-controlled genes (LXR, CYP7A1, SREBP-1, ABCA1, DEC1 and DEC2; all P<0.05), which were significantly associated with the abnormal diurnal rhythms of triglyceride, total cholesterol, aspartate aminotransferase and alanine aminotransferase (all P<0.05) in rats with Adriamycin-induced nephropathy. Furthermore, a protein-protein interaction network was identified. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses based on the human database was conducted to obtain signaling pathway and correlation prediction analyses of overall human clock and clock-controlled gene correlations. Strong correlations of the aforementioned clock genes were detected (avg. local clustering coefficient, 0.849) which suggested significant enrichment in circadian rhythm signaling. The present results indicated that damage to hepatic clock systems may impact blood lipid circadian rhythm disorders in NS, and offer a starting point for understanding the crosstalk between peripheral organs and peripheral clock systems.
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Affiliation(s)
- Peipei Chen
- Department of Nephrology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P.R. China
| | - Ruiyu Zhang
- Department of Nephrology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P.R. China
| | - Lijun Mou
- Department of Nephrology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P.R. China
| | - Xuewang Li
- Department of Nephrology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P.R. China
| | - Yan Qin
- Department of Nephrology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P.R. China
| | - Xuemei Li
- Department of Nephrology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P.R. China
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8
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Serum Lipoprotein (a) Levels in Black South African Type 2 Diabetes Mellitus Patients. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:5743838. [PMID: 27833702 PMCID: PMC5090092 DOI: 10.1155/2016/5743838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 09/08/2016] [Accepted: 09/25/2016] [Indexed: 12/05/2022]
Abstract
Lipoprotein (a) (Lp(a)) which is a low-density lipoprotein-like particle containing apo(a) is considered as an emergent cardiovascular risk factor. Type 2 diabetes mellitus (T2DM) is associated with a two- to threefold increase in the risk of cardiovascular disease (CVD). The aim of this study was to investigate the levels of Lp(a) in Black South African T2DM patients and its association with other metabolic factors. 67 T2DM patients and 48 healthy control participants were recruited for the cross-sectional study. The Lp(a) level was determined by ELISA and the result was analyzed using SPSS. The Lp(a) level in diabetics was found to be significantly increased (P = 0.001) when compared to the normal healthy group. In the diabetic group, the Lp(a) levels correlated significantly with the duration of diabetes (P = 0.008) and oxidized LDL (ox-LDL) levels (P = 0.03) and decreased total antioxidant capacity (P = 0.001). The third tertile of Lp(a) was significantly correlated with increased ox-LDL, C-reactive protein, and triglycerides and decreased total antioxidant capacity.
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9
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Nordestgaard BG, Langsted A. Lipoprotein (a) as a cause of cardiovascular disease: insights from epidemiology, genetics, and biology. J Lipid Res 2016; 57:1953-1975. [PMID: 27677946 DOI: 10.1194/jlr.r071233] [Citation(s) in RCA: 337] [Impact Index Per Article: 42.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Indexed: 12/24/2022] Open
Abstract
Human epidemiologic and genetic evidence using the Mendelian randomization approach in large-scale studies now strongly supports that elevated lipoprotein (a) [Lp(a)] is a causal risk factor for cardiovascular disease, that is, for myocardial infarction, atherosclerotic stenosis, and aortic valve stenosis. The Mendelian randomization approach used to infer causality is generally not affected by confounding and reverse causation, the major problems of observational epidemiology. This approach is particularly valuable to study causality of Lp(a), as single genetic variants exist that explain 27-28% of all variation in plasma Lp(a). The most important genetic variant likely is the kringle IV type 2 (KIV-2) copy number variant, as the apo(a) product of this variant influences fibrinolysis and thereby thrombosis, as opposed to the Lp(a) particle per se. We speculate that the physiological role of KIV-2 in Lp(a) could be through wound healing during childbirth, infections, and injury, a role that, in addition, could lead to more blood clots promoting stenosis of arteries and the aortic valve, and myocardial infarction. Randomized placebo-controlled trials of Lp(a) reduction in individuals with very high concentrations to reduce cardiovascular disease are awaited. Recent genetic evidence documents elevated Lp(a) as a cause of myocardial infarction, atherosclerotic stenosis, and aortic valve stenosis.
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Affiliation(s)
- Børge G Nordestgaard
- Department of Clinical Biochemistry and Copenhagen General Population Study, Herlev and Gentofte Hospital, Copenhagen University Hospital, Herlev, Denmark; and Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anne Langsted
- Department of Clinical Biochemistry and Copenhagen General Population Study, Herlev and Gentofte Hospital, Copenhagen University Hospital, Herlev, Denmark; and Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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10
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Sticchi E, Magi A, Kamstrup PR, Marcucci R, Prisco D, Martinelli I, Mannucci PM, Abbate R, Giusti B. Apolipoprotein(a) Kringle-IV Type 2 Copy Number Variation Is Associated with Venous Thromboembolism. PLoS One 2016; 11:e0149427. [PMID: 26900838 PMCID: PMC4762703 DOI: 10.1371/journal.pone.0149427] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 01/02/2016] [Indexed: 11/18/2022] Open
Abstract
In addition to the established association between high lipoprotein(a) [Lp(a)] concentrations and coronary artery disease, an association between Lp(a) and venous thromboembolism (VTE) has also been described. Lp(a) is controlled by genetic variants in LPA gene, coding for apolipoprotein(a), including the kringle-IV type 2 (KIV-2) size polymorphism. Aim of the study was to investigate the role of LPA gene KIV-2 size polymorphism and single nucleotide polymorphisms (SNPs) (rs1853021, rs1800769, rs3798220, rs10455872) in modulating VTE susceptibility. Five hundred and sixteen patients with VTE without hereditary and acquired thrombophilia and 1117 healthy control subjects, comparable for age and sex, were investigated. LPA KIV-2 polymorphism, rs3798220 and rs10455872 SNPs were genotyped by TaqMan technology. Concerning rs1853021 and rs1800769 SNPs, PCR-RFLP assay was used. LPA KIV-2 repeat number was significantly lower in patients than in controls [median (interquartile range) 11(6–17) vs 15(9–25), p<0.0001]. A significantly higher prevalence of KIV-2 repeat number ≤7 was observed in patients than in controls (33.5% vs 15.5%, p<0.0001). KIV-2 repeat number was independently associated with VTE (p = 4.36 x10-9), as evidenced by the general linear model analysis adjusted for transient risk factors. No significant difference in allele frequency for all SNPs investigated was observed. Haplotype analysis showed that LPA haplotypes rather than individual SNPs influenced disease susceptibility. Receiver operating characteristic curves analysis showed that a combined risk prediction model, including KIV-2 size polymorphism and clinical variables, had a higher performance in identifying subjects at VTE risk than a clinical-only model, also separately in men and women.
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Affiliation(s)
- Elena Sticchi
- Department of Experimental and Clinical Medicine, University of Florence—Atherothrombotic Disease Center, Careggi Hospital, Florence, Italy
| | - Alberto Magi
- Department of Experimental and Clinical Medicine, University of Florence—Atherothrombotic Disease Center, Careggi Hospital, Florence, Italy
| | - Pia R. Kamstrup
- Department of Clinical Biochemistry, Copenhagen University Hospital—Herlev, Herlev, Denmark
| | - Rossella Marcucci
- Department of Experimental and Clinical Medicine, University of Florence—Atherothrombotic Disease Center, Careggi Hospital, Florence, Italy
| | - Domenico Prisco
- Department of Experimental and Clinical Medicine, University of Florence—SOD Patologia Medica, Center for Autoimmune Systemic Diseases, Behçet Center and Lupus Clinic, Careggi Hospital, Florence, Italy
| | - Ida Martinelli
- A. Bianchi Bonomi Hemophilia and Thrombosis Center—Ospedale Maggiore Policlinico, Milan, Italy
| | - Pier Mannuccio Mannucci
- A. Bianchi Bonomi Hemophilia and Thrombosis Center—Ospedale Maggiore Policlinico, Milan, Italy
- Scientific Direction, Fondazione Ca’ Granda–Ospedale Maggiore Policlinico, Milan, Italy
| | - Rosanna Abbate
- Department of Experimental and Clinical Medicine, University of Florence—Atherothrombotic Disease Center, Careggi Hospital, Florence, Italy
| | - Betti Giusti
- Department of Experimental and Clinical Medicine, University of Florence—Atherothrombotic Disease Center, Careggi Hospital, Florence, Italy
- * E-mail:
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11
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Lipoprotein(a): a promising marker for residual cardiovascular risk assessment. DISEASE MARKERS 2013; 35:551-9. [PMID: 24249942 PMCID: PMC3819768 DOI: 10.1155/2013/563717] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 09/03/2013] [Accepted: 09/04/2013] [Indexed: 01/14/2023]
Abstract
Atherosclerotic cardiovascular diseases (CVD) are still the leading cause of morbidity and mortality worldwide, although optimal medical therapy has been prescribed for primary and secondary preventions. Residual cardiovascular risk for some population groups is still considerably high although target low density lipoprotein-cholesterol (LDL-C) level has been achieved. During the past few decades, compelling pieces of evidence from clinical trials and meta-analyses consistently illustrate that lipoprotein(a) (Lp(a)) is a significant risk factor for atherosclerosis and CVD due to its proatherogenic and prothrombotic features. However, the lack of effective medication for Lp(a) reduction significantly hampers randomized, prospective, and controlled trials conducting. Based on previous findings, for patients with LDL-C in normal range, Lp(a) may be a useful marker for identifying and evaluating the residual cardiovascular risk, and aggressively lowering LDL-C level than current guidelines' recommendation may be reasonable for patients with particularly high Lp(a) level.
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12
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Abstract
Plasma lipoprotein(a) [Lp(a)] is a quantitative genetic trait with a very broad and skewed distribution, which is largely controlled by genetic variants at the LPA locus on chromosome 6q27. Based on genetic evidence provided by studies conducted over the last two decades, Lp(a) is currently considered to be the strongest genetic risk factor for coronary heart disease (CHD). The copy number variation of kringle IV in the LPA gene has been strongly associated with both Lp(a) levels in plasma and risk of CHD, thereby fulfilling the main criterion for causality in a Mendelian randomization approach. Alleles with a low kringle IV copy number that together have a population frequency of 25-35% are associated with a doubling of the relative risk for outcomes, which is exceptional in the field of complex genetic phenotypes. The recently identified binding of oxidized phospholipids to Lp(a) is considered as one of the possible mechanisms that may explain the pathogenicity of Lp(a). Drugs that have been shown to lower Lp(a) have pleiotropic effects on other CHD risk factors, and an improvement of cardiovascular endpoints is up to now lacking. However, it has been established in a proof of principle study that lowering of very high Lp(a) by apheresis in high-risk patients with already maximally reduced low-density lipoprotein cholesterol levels can dramatically reduce major coronary events.
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Affiliation(s)
- F Kronenberg
- Division of Genetic Epidemiology, Innsbruck Medical University, Innsbruck, Austria
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13
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Fanshawe AE, Ibrahim M. The current status of lipoprotein (a) in pregnancy: a literature review. J Cardiol 2012; 61:99-106. [PMID: 23165148 DOI: 10.1016/j.jjcc.2012.09.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Revised: 09/06/2012] [Accepted: 09/13/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND AND PURPOSE Lipoprotein (Lp) (a) is a neglected element of the blood lipid profile. It is now recognized as a determinant of coronary heart disease progression and its role in atherosclerosis and its ability to induce thrombosis make it potentially important in the course of normal and complicated pregnancies. Pregnancy involves a major transformation of metabolism to sustain fetal growth. Multiple studies have been conducted on Lp(a) in pregnancy, and it is timely to synthesize and evaluate this evidence. METHODS AND SUBJECTS We reviewed the MEDLINE database for all articles published concerning "lipoprotein a" and "pregnancy" from May 2003 to May 2012. A previous comprehensive review assessed the literature up to May 2003. RESULTS We critically analyzed 14 studies detailing the effect of complications in pregnancy on Lp(a) profile, and subsequent pregnancy outcomes where available. Studies evaluating the normal metabolic response to pregnancy, pregnancies complicated by pre-eclampsia and intra-uterine growth restriction were reviewed. CONCLUSIONS A substantial mass of data has accumulated describing Lp(a) changes in pregnancy. The diversity of study design limits the ability to draw broad-ranging conclusions, but brings into focus the important questions remaining, which we discuss.
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Allian-Sauer MU, Falko JM. Role of apheresis in the management of familial hypercholesterolemia and elevated Lp(a) levels. ACTA ACUST UNITED AC 2011. [DOI: 10.2217/clp.11.43] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Daneshpour MS, Faam B, Hedayati M, Eshraghi P, Azizi F. ApoB (XbaI) polymorphism and lipid variation in Teharnian population. EUR J LIPID SCI TECH 2011. [DOI: 10.1002/ejlt.201000346] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Maryam S Daneshpour
- Obesity Research Center, Research Institute for Endocrine Sciences Shaheed Beheshti University of Medical Sciences, Tehran, I.R. Iran
| | - Bita Faam
- Obesity Research Center, Research Institute for Endocrine Sciences Shaheed Beheshti University of Medical Sciences, Tehran, I.R. Iran
| | - Mehdi Hedayati
- Obesity Research Center, Research Institute for Endocrine Sciences Shaheed Beheshti University of Medical Sciences, Tehran, I.R. Iran
| | - Parisa Eshraghi
- Obesity Research Center, Research Institute for Endocrine Sciences Shaheed Beheshti University of Medical Sciences, Tehran, I.R. Iran
| | - Fereidoun Azizi
- Obesity Research Center, Research Institute for Endocrine Sciences Shaheed Beheshti University of Medical Sciences, Tehran, I.R. Iran
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Xing G, Lin CY, Xing C. A Comparison of Approaches to Control for Confounding Factors by Regression Models. Hum Hered 2011; 72:194-205. [DOI: 10.1159/000332743] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 09/01/2011] [Indexed: 01/08/2023] Open
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Cardiovascular Events in Patients with Increased Lipoprotein (a) – Retrospective Data Analysis in an Outpatient Department of Lipid Disorders. ATHEROSCLEROSIS SUPP 2009; 10:79-84. [DOI: 10.1016/s1567-5688(09)71817-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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18
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Lanktree MB, Rajakumar C, Brunt JH, Koschinsky ML, Connelly PW, Hegele RA. Determination of lipoprotein(a) kringle repeat number from genomic DNA: copy number variation genotyping using qPCR. J Lipid Res 2008; 50:768-72. [PMID: 19060253 DOI: 10.1194/jlr.d800050-jlr200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Plasma lipoprotein(a) [Lp(a)] concentration is related to risk of cardiovascular disease. The defining protein component of Lp(a) particles, apolipoprotein(a) [apo(a)], is encoded by the LPA gene. Apo(a) is extremely heterogeneous in size due to a common copy number variation, leading to a variable number of kringle-IV type 2 (KIV2)-like domains. Alleles with fewer KIV2 repeats, encoding smaller apo(a) isoforms, are associated with higher plasma Lp(a) concentrations. Two principal methods to detect variation in KIV2 repeat number are electrophoresis with immunoblotting to detect apo(a) protein isoforms or pulse-field electrophoresis of unamplified genomic DNA to detect the variation of the LPA gene. Both methods are technically challenging, laborious, and time consuming. Here, we report a rapid method to determine the number of KIV2 repeats in LPA from genomic DNA using quantitative real-time polymerase chain reaction (qPCR). With qPCR, we found KIV2 repeat number was correlated with both apo(a) isoform size as determined by immunoblotting (r(s) = 0.50, P < 1 x 10(-6)) and with plasma Lp(a) concentration (r(s) = 0.30, P < 1 x 10(-6)). The qPCR technique permits rapid evaluation of apo(a) size from genomic DNA, and thus would provide an adjunctive genomic variable, in addition to LPA single nucleotide polymorphisms, for evaluating the genetic determinants of plasma Lp(a) concentration in genetic epidemiology studies of cardiovascular disease outcomes.
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Affiliation(s)
- Matthew B Lanktree
- Robarts Research Institute, Departments of Medicine and Biochemistry, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
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Defesche JC, Ree MA, Kastelein JJP, Diermen DE, Janssens NWE, Doormaal JJ, Hayden MR. Detection of the Pro664-Leu mutation in the low-density lipoprotein receptor and its relation to lipoprotein(a) levels in patients with familial hypercholesterolemia of Dutch ancestry from The Netherlands and Canada. Clin Genet 2008. [DOI: 10.1111/j.1399-0004.1992.tb03255.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Defesche JC, Ree MA, Kastelein JJP, Diermen DE, Janssans NWE, Doormaal JJ, Hayden MR. Detection of the Pro664-Leu mutation in the low-density lipoprotein receptor and its relation to lipoprotein(a) levels in patients with familial hypercholesterolemia of Dutch ancestry from The Netherlands and Canada. Clin Genet 2008. [DOI: 10.1111/j.1399-0004.1992.tb03256.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Genome-wide linkage analysis for identifying quantitative trait loci involved in the regulation of lipoprotein a (Lpa) levels. Eur J Hum Genet 2008; 16:1372-9. [DOI: 10.1038/ejhg.2008.114] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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22
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Association between lipoprotein(a) levels, apo(a) isoforms and family history of premature CAD in young Asian Indians. Clin Biochem 2008; 41:453-8. [DOI: 10.1016/j.clinbiochem.2008.01.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2007] [Revised: 01/11/2008] [Accepted: 01/15/2008] [Indexed: 01/17/2023]
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23
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Baldo G, Giunco S, Kontothanassis D, Baiocchi MR, Valerio A, Frego M. Different apoprotein(a) isoform proportions in serum and carotid plaque. Atherosclerosis 2007; 193:177-85. [PMID: 16839560 DOI: 10.1016/j.atherosclerosis.2006.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Revised: 05/24/2006] [Accepted: 06/02/2006] [Indexed: 10/24/2022]
Abstract
INTRODUCTION Cardio- and/or cerebro-vascular risk are associated with high lipoprotein (a) [Lp(a)] levels and low-molecular-weight (LMW) apo(a) isoforms. Aims of this study were to evaluate the deposition of apo(a) isoforms and apoprotein B (apo B) in atherosclerotic plaque from patients (males and females) who had carotid endarterectomy for severe stenosis, and to identify differences between patients classified by gender and divided according to the stability or instability of their plaques. MATERIALS AND METHODS We determined lipids, apo B and Lp(a) in serum and plaque extracts from 55 males and 25 females. Apo(a) was phenotyped and isoforms were classified by number of kringle IV (KIV) repeats. RESULTS Lp(a) levels were higher in female serum and plaque extracts than in male samples, while apo B levels were lower. More Lp(a) than apo B deposition was observed in plaque after normalization for serum levels. Thirty-one different apo(a) isoforms were detected in our patients, with a double band phenotype in 94% of cases. In both sexes, the low/high (L/H) molecular weight apo(a) isoform expression ratio was significantly higher in plaque than in serum. Females with unstable plaques had higher Lp(a) levels in both serum and tissue extracts, and fewer KIV repeats of the principal apo(a) isoform in the serum than the other female group or males. CONCLUSIONS In both sexes, the same apo(a) isoforms are found in serum and atherosclerotic plaque, but in different proportions: in plaque, LMW apo(a) is almost always more strongly accumulated than HMW apo(a), irrespective of any combination of apo(a) isoforms in double band phenotypes or Lp(a) serum levels. Moreover, serum and tissue Lp(a) levels were higher in females than in males, and particularly in the group with unstable plaques.
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Affiliation(s)
- Goretta Baldo
- Department of Medical and Surgical Sciences, University of Padua, Italy.
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Sticchi E, Lenti M, Giusti B, Sestini I, Abbate R, Fatini C. LPA +93C>T and +121G>A polymorphisms detection by electronic microchip technology. Mol Genet Metab 2007; 91:79-84. [PMID: 17324601 DOI: 10.1016/j.ymgme.2006.12.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Revised: 12/20/2006] [Accepted: 12/20/2006] [Indexed: 10/23/2022]
Abstract
Lipoprotein(a) [Lp(a)] is a LDL-like particle containing a single copy of apolipoprotein B-100 (apoB-100), covalently attached to apolipoprotein(a) [apo(a)]. Apo(a) is encoded by LPA gene (6q26-27), and it has been hypothesized that LPA +93C>T and +121G>A polymorphisms in the 5' flanking region could influence the apolipoprotein(a) synthesis, so affecting Lp(a) levels. In order to permit a rapid detection of LPA polymorphisms, we performed an analysis protocol for the SNPs detection through Nanogen Technology with the Universal Reporting System, and we compared our results with those obtained with a more conventional method, such as PCR-RFLP assay. Our experiments evidenced that Nanogen Technology may be used as a high-throughput tool in LPA +93C>T and +121G>A polymorphisms analysis, minimizing the hands-on time and the costs for the SNPs detection. In particular, this Technology allows the analysis of polymorphisms at the LPA locus, able to modulate the levels of Lp(a), a relevant marker of atherosclerosis.
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Affiliation(s)
- Elena Sticchi
- Fondazione Don Carlo Gnocchi, ONLUS, S Maria degli Ulivi-IRCCS, Firenze, Italy.
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Falchi M, Andrew T, Snieder H, Swaminathan R, Surdulescu GL, Spector TD. Identification of QTLs for serum lipid levels in a female sib-pair cohort: a novel application to improve the power of two-locus linkage analysis. Hum Mol Genet 2005; 14:2971-9. [PMID: 16135557 DOI: 10.1093/hmg/ddi327] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Using a novel approach for a two-locus model that provides a greatly increased power to detect multiple quantitative trait loci (QTLs) in simulated data, we identified in a sample of 961 female sib-pairs, three genome-wide significant QTLs for apolipoprotein A1 on chromosomes 8p21.1-q13.1 (LOD score 3.71), 9q21.32-33.1 (LOD score 3.28) and 10p15.1-p13 (LOD score 5.51), two for lipoprotein (a) on chromosomes 6q25.2-q27 (LOD score 10.18) and 21q21.1-q21.3 (LOD score 4.57) and two for triglycerides on chromosomes 4q28.3-32.1 (LOD score 3.71) and 5q23.1-q32 (LOD score 3.60). The two-locus ordered-subset analysis has led to the confirmation of known and likely identification of novel regions linked to serum lipid levels that would have otherwise been missed and deserves wider application in linkage analyses of quantitative traits. Given the relative lack of power for the sample sizes commonly used in human genetics linkage studies, minor QTL effects often go undetected and those that are detected will be upwardly biased. We show through simulation that the discrepancy between the real and estimated QTL-effects is often likely to generate an unpredictable source of false-negative errors, using multi-locus models, reducing the power to detect multiple QTLs through oligogenic linkage analysis. The successful simultaneous modelling of the identified QTLs in a multi-locus context helps to eliminate false positives and increases the power to detect linkages, adding compelling evidence that they are likely to be reliable QTLs for these lipid traits.
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Affiliation(s)
- Mario Falchi
- Twin Research and Genetic Epidemiology Unit, St Thomas' Hospital, London, UK.
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Calmarza P, Cordero J, Santos V, Vella JC. Apolipoprotein(a) isoforms in infarcted men under 60 years old. Clin Biochem 2005; 37:911-8. [PMID: 15369723 DOI: 10.1016/j.clinbiochem.2003.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2003] [Accepted: 06/28/2003] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The aim of this study was to compare the Lp(a) concentration and the frequency distribution of the apo(a) isoforms of a myocardial infarcted male group under 60 years old and a group of healthy subjects (controls). METHODS A total of 111 infarcted men and 99 men free from disease were enrolled in this study. Lp(a) concentrations were measured by a commercial available rate nephelometry method, and apolipoprotein(a) isoform analysis was performed by sodium dodecyl sulfate (SDS) polyacrilamide gel electrophoresis (PAGE) and immunoblotting. RESULTS Infarcted patients had higher Lp(a) concentrations (0.33 +/- 0.36 g/l) than noninfarcted subjects did (0.19 +/- 0.22 g/l), and these differences were significant (P = 0.001). Infarcted patients have also shown a greater proportion of elevated (> or = 0.30 g/l) Lp(a) concentrations 37.8% than controls 20.2% (P < 0.01). The distributions of apo(a) phenotypes for patients with myocardial infarction and controls were remarkably different (P < 0.001), and the proportions of smaller isoforms were significantly different by chi-square analysis (P < 0.01). CONCLUSIONS Infarcted patients under 60 years old display higher Lp(a) concentrations and a significantly higher proportion of low molecular weight apolipoprotein(a) isoforms than controls.
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Affiliation(s)
- Pilar Calmarza
- Hospital General Yagüe., Avda. del Cid no. 96, 09005 Burgos, Spain.
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Tavridou A, Unwin N, Bhopal R, Laker MF. Predictors of lipoprotein(a) levels in a European and South Asian population in the Newcastle Heart Project. Eur J Clin Invest 2003; 33:686-92. [PMID: 12864778 DOI: 10.1046/j.1365-2362.2003.01201.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Understanding of the higher susceptibility of South Asians to coronary heart disease is limited. One explanation is the combination of high prevalence of insulin resistance with higher lipoprotein(a) levels. MATERIALS AND METHODS Lipoprotein(a) levels and genotypes in three South Asian groups aged 25-74 years (Indian, Pakistani, Bangladeshi) were compared with a European population in a cross-sectional study. Biochemical measurements included lipids, apolipoprotein A1 and B, glucose, insulin and fibrinogen. Insulin sensitivity was calculated using the homoeostasis model assessment method (HOMA). RESULTS There was no significant difference in lipoprotein(a) levels between South Asian and European men. South Asian women combined had higher lipoprotein(a) levels than European women, a difference probably resulting from higher lipoprotein(a) levels in Pakistani women compared with Indian and Bangladeshi women. Fasting insulin and HOMA were negatively associated with Lp(a) in South Asians though the associations were statistically significant only in men. There were only modest associations between most cardiovascular risk factors and Lp(a). Twenty-seven apolipoprotein(a) size alleles were detected in the three South Asian groups ranging from 16 to 43 kringle-IV repeats. The apolipoprotein(a) size polymorphism explained 23% of the variability in lipoprotein(a) levels in South Asians. CONCLUSIONS There were few nongenetic predictors of lipoprotein(a) levels in South Asians and Europeans. The lack of difference in Lp(a) between the South Asian and European men and the fact that differences between the women seemed to be confined to the Pakistani group offer little support to the hypothesis that higher Lp(a) levels contribute to the increased risk of heart disease in South Asians. Our findings do not support the hypothesis that susceptibility to heart disease in South Asians results from a combination of high insulin resistance and high Lp(a) levels.
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Affiliation(s)
- A Tavridou
- Department of Pharmacology, ELPEN Pharmaceutical Co. Inc., Pikermi, Attika, Greece.
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Barkley RA, Brown AC, Hanis CL, Kardia SL, Turner ST, Boerwinkle E. Lack of genetic linkage evidence for a trans-acting factor having a large effect on plasma lipoprotein[a] levels in African Americans. J Lipid Res 2003; 44:1301-5. [PMID: 12730294 DOI: 10.1194/jlr.m300163-jlr200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The distribution of plasma lipoprotein[a] (Lp[a]) concentrations, a risk factor for cardiovascular disease, varies greatly among racial groups, with African Americans having values that are shifted toward higher levels than those of whites. The underlying cause of this heterogeneity is unknown, but a role for "trans-acting" factors has been hypothesized. This study used genetic linkage analysis to localize genetic factors influencing Lp[a] levels in African Americans that were absent in other populations; linkage results were analyzed separately in non-Hispanic whites, Hispanic whites, and African Americans. As expected, all three samples showed highly significant linkage at the approximate location of the lysophosphatidic acid locus. The white populations also independently had regions of significant linkage on chromosome 19 (LOD 3.80) and suggestive linkage on chromosomes 12 (LOD 1.60), 14 (LOD 2.56), and 19 (LOD 2.52). No linkage evidence was found to support the hypothesis of another single gene with large effects specifically segregating in African Americans that may account for their elevated Lp[a] levels.
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Affiliation(s)
- Ruth Ann Barkley
- Human Genetics Center and Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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Wang W, Hu D, Lee ET, Fabsitz RR, Welty TK, Robbins DC, Howard BV. Lipoprotein(a) in American Indians is low and not independently associated with cardiovascular disease. The Strong Heart Study. Ann Epidemiol 2002; 12:107-14. [PMID: 11880218 DOI: 10.1016/s1047-2797(01)00273-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
PURPOSE To evaluate the distribution of lipoprotein(a) (Lp(a)) and assess its association to cardiovascular disease (CVD) in American Indians. METHODS Lp(a) was measured in 3991 American Indians (aged 45-74 years with no prior history of CVD at baseline) from 13 communities in Arizona, Oklahoma, and South/North Dakota. They were followed prospectively from 1989 to 1997 for CVD. The distribution of Lp(a) was examined by center, sex, and diabetic status. Spearman correlation coefficients and Cox regression models were used to evaluate the association of Lp(a) to CVD. RESULTS A total of 388 participants subsequently developed CVD. Median Lp(a) concentration in American Indians was 3.0 mg/dl. This was almost half of that in whites and one sixth in blacks from the CARDIA study measured by the same method. Nondiabetic participants had significantly higher Lp(a) levels than diabetic participants for both genders. Lp(a) levels were higher in women than in men for nondiabetic participants, but there was no gender difference for diabetic participants. Correlation analysis showed Lp(a) was significantly negatively correlated with the degree of Indian heritage, insulin, triglycerides (TG), fasting plasma glucose (FPG), and 2-hour plasma glucose (2hPG), and positively with low-density lipoproteins (LDL), apoprotein B (apoB), and fibrinogen (FIB). In Cox regression models, adjusting for other risk factors, Lp(a) was no longer a significant predictor of CVD in either diabetic or nondiabetic participants. CONCLUSIONS The lower concentration of Lp(a) in American Indians and the high correlation with Indian heritage confirm the concept that Lp(a) concentration is in large part genetically determined. Lp(a) concentration is not an independent predictor of CVD among American Indians; it is higher in those who develop CVD because of its positive correlation with LDL, apoB, and FIB.
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Affiliation(s)
- Wenyu Wang
- Center for American Indian Health Research, College of Public Health, University of Oklahoma, Oklahoma City, OK, USA
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Meinertz H, Nilausen K, Hilden J. Alcohol-extracted, but not intact, dietary soy protein lowers lipoprotein(a) markedly. Arterioscler Thromb Vasc Biol 2002; 22:312-6. [PMID: 11834534 DOI: 10.1161/hq0202.103998] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We previously found that dietary soy protein produces higher lipoprotein(a) [Lp(a)] plasma concentrations than does casein. This study tested the hypothesis that soy protein contains Lp(a)-raising alcohol-removable components. Twelve normolipidemic women and men consumed, in a crossover design, liquid-formula diets containing casein, soy protein, or alcohol-extracted soy protein. Dietary periods of 32 days were separated by washout periods on self-selected diets. Fasting lipid and Lp(a) levels were measured throughout. Median Lp(a) concentration was >2-fold greater after 28 to 32 days on a soy protein diet than after an extracted soy protein diet (P<0.001). Lp(a) concentrations after casein and extracted soy protein diets were virtually identical. Women and men responded similarly. When the switch was made from a self-selected to a soy protein diet, median Lp(a) concentration increased 16% after 1 week (P<0.01) and subsequently decreased toward baseline; extracted soy protein and casein diets never exhibited increased median Lp(a) levels, and after 28 to 32 days, these levels were decreased >60% below baseline (P<0.001 and P<0.01, respectively). Low density lipoprotein cholesterol concentrations were not different after the 3 experimental diets. The data indicate that (1) dietary soy protein can increase Lp(a) concentrations, (2) this effect is eliminated after alcohol extraction, and (3) high Lp(a) concentrations may be markedly reduced by diet.
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Affiliation(s)
- Hans Meinertz
- Department of Medicine B, National University Hospital, University of Copenhagen, Copenhagen, Denmark.
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Ober C, Abney M, McPeek MS. The genetic dissection of complex traits in a founder population. Am J Hum Genet 2001; 69:1068-79. [PMID: 11590547 PMCID: PMC1274354 DOI: 10.1086/324025] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2001] [Accepted: 08/23/2001] [Indexed: 11/03/2022] Open
Abstract
We estimated broad heritabilities (H(2)) and narrow heritabilities (h(2)) and conducted genomewide screens, using a novel association-based mapping approach for 20 quantitative trait loci (QTLs) among the Hutterites, a founder population that practices a communal lifestyle. Heritability estimates ranged from.21 for diastolic blood pressure (DBP) to.99 for whole-blood serotonin levels. Using a multipoint method to detect association under a recessive model we found evidence of major QTLs for six traits: low-density lipoprotein (LDL), triglycerides, lipoprotein (a) (Lp[a]), systolic blood pressure (SBP), serum cortisol, and whole-blood serotonin. Second major QTLs for Lp(a) and for cortisol were identified using a single-point method to detect association under a general two-allele model. The heritabilities for these six traits ranged from.37 for triglycerides to.99 for serotonin, and three traits (LDL, SBP, and serotonin) had significant dominance variances (i.e., H(2) > h(2)). Surprisingly, there was little correlation between measures of heritability and the strength of association on a genomewide screen (P>.50), suggesting that heritability estimates per se do not identify phenotypes that are influenced by genes with major effects. The present study demonstrates the feasibility of genomewide association studies for QTL mapping. However, even in this young founder population that has extensive linkage disequilibrium, map densities <<5 cM may be required to detect all major QTLs.
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Affiliation(s)
- C Ober
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA.
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Császár A, Füst G, Nagy B, Szalai C, Karádi I, Duba J, Prohászka Z, Horváth L, Dieplinger H. The association of serum lipoprotein(a) levels, apolipoprotein(a) size and (TTTTA)(n) polymorphism with coronary heart disease. Clin Chim Acta 2001; 309:45-51. [PMID: 11408005 DOI: 10.1016/s0009-8981(01)00500-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The association between lipoprotein(a) levels, apolipoprotein(a) size and the (TTTTA)(n) polymorphism which is located in the 5' non-coding region of the apo(a) gene was studied in 263 patients with severe coronary heart disease and 97 healthy subjects. METHODS Lp(a) levels were measured by ELISA, apo(a) isoform size was determined by SDS-agarose gel electrophoresis, and analysis of the (TTTTA)(n) was carried out by PCR. For statistical calculation, both groups were divided into low (at least one apo(a) isoform with < or = 22 Kringle IV) and high (both isoforms with >22 KIV) apo(a) isoform sizes, and into low number (<10 in both alleles) and high number of (> or =10 at least one allele) TTTTA repeats. RESULTS Lp(a) levels were higher (P=0.007), apo(a) isoforms size < or =22 KIV and TTTTA repeats > or = 10 were more frequent (P=0.007 and 0.01) in cases than in controls. Lp(a) levels were found to be increased with low apo(a) weight in both groups (both P<0.0001). In multivariate logistic regression analysis, only the Lp(a) levels (P=0.005) and (TTTTA)(n) polymorphism (P=0.002) were found to be significantly associated with CHD. CONCLUSION Nevertheless, these results indicate that in CHD patients the (TTTTA)(n) polymorphism has an effect on Lp(a) levels which is independent of the apo(a) size.
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Hoogeveen RC, Gambhir JK, Gambhir D, Kimball KT, Ghazzaly K, Gaubatz JW, Vaduganathan M, Rao RS, Koschinsky M, Morrisett JD. Evaluation of Lp[a] and other independent risk factors for CHD in Asian Indians and their USA counterparts. J Lipid Res 2001. [DOI: 10.1016/s0022-2275(20)31172-x] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Røsby O, Berg K. LPA gene: interaction between the apolipoprotein(a) size ('kringle IV' repeat) polymorphism and a pentanucleotide repeat polymorphism influences Lp(a) lipoprotein level. J Intern Med 2000; 247:139-52. [PMID: 10672142 DOI: 10.1046/j.1365-2796.2000.00628.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVES In order to search for factors influencing the Lp(a) lipoprotein level, we have examined the apolipoprotein(a) (apo(a)) size polymorphism as well as a pentanucleotide (TTTTA) repeat polymorphism in the 5' control region of the LPA gene. DESIGN Lp(a) lipoprotein levels were compared between individuals with different genotypes as defined by pulsed field gel electrophoresis of DNA plugs, and PCR of DNA samples followed by polyacrylamide gel electrophoresis. DNA plugs and DNA were prepared from blood samples collected from blood donors. RESULTS Twenty-seven different K IV repeat alleles were observed in the 71 women and 92 men from which apo(a) size polymorphism results were obtained. Alleles encoding 26-32 Kringle IV repeats were the most frequent. Alleles encoding seven to 11 TTTTA repeats were detected in the 84 women and 122 men included in the pentanucleotide polymorphism study, and homozygosity for eight TTTTA repeats was the most common genotype. The eight TTTTA repeat allele occurred with almost any apo(a) allele. An inverse relationship between number of K IV repeats and Lp(a) concentration was confirmed. The contributions of the apo(a) size polymorphism and the pentanucleotide repeat polymorphism to the interindividual variance of Lp(a) lipoprotein concentrations were 9.7 and 3.5%, respectively (type IV sum of squares). Nineteen per cent of the variance in Lp(a) lipoprotein level appeared to be the result of the multiplication product (interaction) between the apo(a) size polymorphism and the pentanucleotide repeat polymorphism. CONCLUSIONS The contribution of the apo(a) size polymorphism alone to the variation in Lp(a) lipoprotein level was lower than previously reported. However, the multiplicative interaction effect between the K IV repeat polymorphism and the pentanucleotide repeat polymorphism may be an important factor explaining the variation in Lp(a) lipoprotein levels among the populations.
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Affiliation(s)
- O Røsby
- Institute of Medical Genetics, University of Oslo, Norway.
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35
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Nagy B, Rigó J, Fintor L, Romics L, Papp Z, Karádi I. Distribution of apolipoprotein(a) isoforms in normotensive and severe preeclamptic women. THE JOURNAL OF MATERNAL-FETAL MEDICINE 1999; 8:270-4. [PMID: 10582861 DOI: 10.1002/(sici)1520-6661(199911/12)8:6<270::aid-mfm7>3.0.co;2-e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Preeclampsia is a pregnancy-related disorder constituting one of the primary causes of worldwide maternal and fetal mortality, but despite intensive research its pathogenesis remains unclear. Lipids have been implicated in the development of preeclampsia, although this possible association remains controversial and not yet fully investigated. This study set out to examine the potential association between lipoprotein(a) and the development of severe preeclampsia. The focus of this study was to investigate the potential utility of apolipoprotein(a) isoforms as possible diagnostic markers for identifying women at risk for developing preeclampsia. METHODS Study participants included a control group of nonpregnant female volunteers (n = 59), a group of healthy pregnant (normotensive) female volunteers (n = 51), and a group of severe preeclamptic female volunteers (n = 59). Serum lipoprotein(a) concentrations were measured using double-antibody ELISA methods and were found to be 17.0+/-23.6 mg/dl among nonpregnant controls (n = 51), 15.9+/-15.8 mg/dl among healthy pregnant normotensives (n = 51), and 16.2+/-16.7 mg/dl in the preeclamptic group (n = 59). In addition, apolipoprotein (a) isoforms were identified using high-resolution SDS-agarose electrophoresis followed by immunoblotting. RESULTS We detected no significant differences between the groups studied in the distribution of isoforms (Chi-square = 1.21, df = 4, P = 0.89); however, in a 1-week interval we detected a 42.2% rise in Lp(a) levels as well as a 67.1% rise in C-reactive protein concentrations among 10 volunteers in the preeclamptic group (median = 9.6; P < 0.05). CONCLUSIONS Although the exact mechanism of pathogenesis continues to elude investigators, our results suggest that lipoprotein(a) may act as an acute-phase reactant during preeclampsia. Although our results are preliminary, they are consistent with growing evidence implicating lipids as among those factors involved in the etiology of preeclampsia. Changes in apolipoprotein(a) may be among those important biochemical markers that are found to be useful in the early identification of high-risk women and warrant further study.
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Affiliation(s)
- B Nagy
- First Department of Obstetrics and Gynecology, Semmelweis University Medical School, Budapest, Hungary.
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36
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Min WK, Chun S, Hwang SH, Park H. No relationship between serum lipoprotein(a) and albumin concentrations in patients with acute phase response. Ann Clin Biochem 1999; 36 ( Pt 5):617-21. [PMID: 10505212 DOI: 10.1177/000456329903600509] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The aim of this study was to investigate the relationship between lipoprotein(a) [Lp(a)] and albumin concentrations in the serum of patients with acute phase response (APR). We have compared the Lp(a) concentrations and apolipoprotein [apo(a)] phenotypes of 40 controls with those of 40 APR patients with normoalbuminaemia and 40 APR patients with hypoalbuminaemia. We have also compared concentrations of haptoglobin (Hp) and alpha 1-antitrypsin (AAT) containing a high sialic acid content, similar to Lp(a). The mean serum Lp(a) concentration (SD) of the 40 controls was 0.190 (0.142) g/L. The mean serum Lp(a) concentration was 0.358 (0.257) g/L (P < 0.001) in 80 APR patients. However, there was no difference in serum Lp(a) concentrations between the APR patients with hypoalbuminaemia [0.353 (0.268) g/L] and the APR patients with normoalbuminaemia [0.362 (0.249) g/L]. No significant difference was found in the distributions of apo(a) phenotypes between the controls, the APR patients with hypoalbuminaemia, and the APR patients with normoalbuminaemia (P = 0.183). In the APR patients, the serum concentrations of AAT and Hp were respectively 2.709 (0.822) g/L and 2.631 (1.340) g/L, whereas those of normal controls were respectively 1.422 (0.219) g/L (P < 0.001) and 0.956 (0.442) g/L (P < 0.001). In conclusion, the Lp(a) is one of the acute phase reactants whose synthesis concurrently increases with other APRs, especially those with a high sialic acid content. The increase of the serum Lp(a) concentrations in the APR patients is not related to serum albumin concentration.
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Affiliation(s)
- W K Min
- Department of Clinical Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
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37
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Abstract
Lipoprotein(a) is an atherogenic, cholesterol ester-rich lipoprotein of unknown physiological function. The unusual species distribution of lipoprotein(a) and the extreme polymorphic nature of its distinguishing apolipoprotein component, apolipoprotein(a), have provided unique challenges for the investigation of its biochemistry, genetics, metabolism and atherogenicity. Some fundamental questions regarding this enigmatic lipoprotein have escaped elucidation, as will be highlighted in this review.
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Affiliation(s)
- H H Hobbs
- Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas 75235, USA.
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38
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Milionis HJ, Elisaf MS, Tselepis A, Bairaktari E, Karabina SA, Siamopoulos KC. Apolipoprotein(a) phenotypes and lipoprotein(a) concentrations in patients with renal failure. Am J Kidney Dis 1999; 33:1100-6. [PMID: 10352198 DOI: 10.1016/s0272-6386(99)70147-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Patients with renal failure have an increased incidence of atherosclerotic disease. Numerous studies have shown that these patients show increased serum lipoprotein(a) [Lp(a)] concentrations compared with the control population. However, variable alleles at the apolipoprotein(a) [apo(a)] gene locus determine to a large extent the Lp(a) concentration in the general population. We therefore undertook the present study to evaluate apo(a) phenotypes and Lp(a) serum concentrations in a large number of patients with renal disease. Seventy-nine patients treated by hemodialysis (HD), 47 patients treated by continuous ambulatory peritoneal dialysis (CAPD), 68 patients with mild/moderate chronic renal failure (CRF) and serum creatinine levels of 1.8 to 8 mg/dL, and 73 healthy controls were studied. All patients showed significantly elevated median serum Lp(a) concentrations in comparison with controls: HD patients, 15.7 mg/dL (P < 0.01); CAPD patients, 20 mg/dL (P < 0. 005); CRF patients, 15.1 mg/dL (P < 0.01) versus controls, 7 mg/dL. The greater Lp(a) values in all groups were not explained by differences in isoform frequencies, whereas their increase was apo(a)-type specific. Thus, patients in all groups with high-molecular-weight (HMW) apo(a) isoforms showed a significant elevation of Lp(a) levels, whereas serum Lp(a) concentrations in patients with low-molecular-weight (LMW) isoforms were not significantly different from controls, except for CAPD patients, who presented increased serum Lp(a) concentrations. We conclude that in patients with renal failure, even of mild/moderate degree, as well as in patients with end-stage renal disease undergoing HD or CAPD, elevated Lp(a) concentrations are mainly observed in those with HMW apo(a) phenotypes.
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Affiliation(s)
- H J Milionis
- Laboratory of Biochemistry, University of Ioannina, Greece
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39
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Brazier L, Tiret L, Luc G, Arveiler D, Ruidavets JB, Evans A, Chapman J, Cambien F, Thillet J. Sequence polymorphisms in the apolipoprotein(a) gene and their association with lipoprotein(a) levels and myocardial infarction. The ECTIM Study. Atherosclerosis 1999; 144:323-33. [PMID: 10407493 DOI: 10.1016/s0021-9150(98)00333-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Lp(a) concentrations are largely determined by apo(a) isoform size, but several studies have shown that apo(a) isoforms could not entirely explain the increase of Lp(a) levels observed in patients with coronary heart disease (CHD). Since up to 90% of the variance in Lp(a) levels has been suggested to be attributable to the apo(a) locus, the hypothesis that polymorphisms of the apo(a) gene other than size could contribute to the increase of Lp(a) levels in CHD patients must be considered. This hypothesis was tested in the ECTIM Study comparing 594 patients with myocardial infarction and 682 control subjects in Northern Ireland and France. In addition to apo(a) phenotyping, five previously described polymorphisms of the apo(a) gene were genotyped: a (TTTTA)n repeat at position -1400 from the ATG, a G/A at -914, a C/T at -49, a G/A at -21 and a Met/Thr affecting amino acid 4168. As reported earlier [Parra HJ, Evans AE, Cambou JP, Amouyel P, Bingham A, McMaster D, Schaffer P, Douste-Blazy P, Luc G, Richard JL, Ducimetiere P, Fruchart JC, Cambien F. A case-control study of lipoprotein particles in two populations at contrasting risk for coronary heart disease. The ECTIM study. Arterioscler Thromb 1992; 12:701-707], mean Lp(a) levels were higher in cases than in controls (20.7 vs 14.6 mg/dl in Belfast, 17.2 vs 8.9 mg/dl in France, P < 0.001 for case-control and population differences). In the present study, mean apo(a) isoform size differed significantly between cases and controls (25.7 vs 26.6 kr in Belfast, 25.9 vs 27.4 kr in France, P < 0.001 for case-control and P = 0.13 for population difference). After adjustment for apo(a) isoforms, Lp(a) levels remained significantly higher in cases than in controls (difference, 4.6 mg/dl; P < 0.001). Genotype and allele frequencies did not differ significantly between cases and controls for any of the five polymorphisms studied. The five polymorphisms were in strong linkage disequilibrium and had a combined heterozygosity of 0.83. In multivariate regression analysis adjusted for apo(a) isoforms, only the (TTTTA)n polymorphism was significantly associated with Lp(a) levels; it explained 4.5% of Lp(a) variability in cases and 3.1% in controls. The Lp(a) case/control difference was not reduced after taking into account the (TTTTA)n effect. We conclude that the increase of Lp(a) levels observed in MI cases, and which was not directly attributable to apo(a) size variation, was not related to the five polymorphisms of the apo(a) gene considered.
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Affiliation(s)
- L Brazier
- Institut National de la Santé et de la Recherche Médicale, Unité U321, Lipoprotéines et Athérogénèse, Hôpital de la Pitié, 83 Boulevard de l'Hôpital, Paris, France
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40
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Page GP, Amos CI. Comparison of linkage-disequilibrium methods for localization of genes influencing quantitative traits in humans. Am J Hum Genet 1999; 64:1194-205. [PMID: 10090905 PMCID: PMC1377844 DOI: 10.1086/302331] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Linkage disequilibrium has been used to help in the identification of genes predisposing to certain qualitative diseases. Although several linkage-disequilibrium tests have been developed for localization of genes influencing quantitative traits, these tests have not been thoroughly compared with one another. In this report we compare, under a variety of conditions, several different linkage-disequilibrium tests for identification of loci affecting quantitative traits. These tests use either single individuals or parent-child trios. When we compared tests with equal samples, we found that the truncated measured allele (TMA) test was the most powerful. The trait allele frequencies, the stringency of sample ascertainment, the number of marker alleles, and the linked genetic variance affected the power, but the presence of polygenes did not. When there were more than two trait alleles at a locus in the population, power to detect disequilibrium was greatly diminished. The presence of unlinked disequilibrium (D'*) increased the false-positive error rates of disequilibrium tests involving single individuals but did not affect the error rates of tests using family trios. The increase in error rates was affected by the stringency of selection, the trait allele frequency, and the linked genetic variance but not by polygenic factors. In an equilibrium population, the TMA test is most powerful, but, when adjusted for the presence of admixture, Allison test 3 becomes the most powerful whenever D'*>.15.
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Affiliation(s)
- G P Page
- Department of Epidemiology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
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41
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Gaw A, Docherty G, Brown EA, Ford I. Predictors of plasma lipoprotein(a) concentration in the West of Scotland Coronary Prevention Study cohort. Atherosclerosis 1999; 143:445-50. [PMID: 10217375 DOI: 10.1016/s0021-9150(98)00305-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An elevated plasma lipoprotein(a) (Lp(a)) concentration is an independent risk factor for coronary heart disease (CHD). Plasma Lp(a) levels are believed to be predominantly controlled by the APO(a) gene, which encodes the apo(a) glycoprotein moiety of the Lp(a) particle. However, other parameters in the lipoprotein profile as well as co-existing disease states or personal traits have been proposed as co-varieties. In order to examine these potential controlling factors in greater detail than previously possible, 1760 unrelated Caucasian subjects were studied, from which were identified 907 with a single expressing APO(a) allele. This strategy was followed to obviate the difficulty in dealing with the co-expression of different apo(a) isoforms and the resulting compound plasma Lp(a) level. After cube-root transformation of the plasma Lp(a) levels to normalise their distribution, a series of correlates were computed. There was no good correlation between Lp(a) concentration and any other measured lipid or lipoprotein in the lipid profile or with any other variable examined, with the important exception of the length of the expressed apo(a) isoform (r = -0.491, P = 0.0001). We conclude that in this population the plasma Lp(a) concentration is not predicted by the plasma lipid profile, alcohol intake, or smoking status but is predicted, albeit incompletely, by the length polymorphism of the APO(a) gene.
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Affiliation(s)
- A Gaw
- Department of Pathological Biochemistry, Royal Infirmary, Glasgow, UK
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42
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Abstract
Lipoprotein(a) is a plasma particle which is considered to be a risk factor for the development of coronary heart disease. Plasma levels of lipoprotein(a) are affected by different types of dietary fat and steroid hormones. Two regions upstream of the apolipoprotein(a) promoter have been isolated which could be the site of regulation of apolipoprotein(a) gene transcription.
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Affiliation(s)
- L Puckey
- Clinical Sciences Centre, Imperial College School of Medicine, Hammersmith Hospital, London, UK
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43
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Gaw A, Brown EA, Ford I. Impact of apo(a) length polymorphism and the control of plasma Lp(a) concentrations: evidence for a threshold effect. Arterioscler Thromb Vasc Biol 1998; 18:1870-6. [PMID: 9848878 DOI: 10.1161/01.atv.18.12.1870] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Plasma lipoprotein(a) [Lp(a)] levels are believed to be controlled predominantly by the apolipoprotein(a) [APO(a)] gene, which encodes the apo(a) glycoprotein, a key constituent of the Lp(a) particle. Previously, it has been accepted that the plasma Lp(a) level is inversely proportional to apo(a) length. To examine this relationship in greater detail, 1500 unrelated, homogeneous (sex, race, age, plasma lipids) subjects were studied, from which 769 were identified with a single-expressing APO(a) allele. A bimodal frequency distribution of apo(a) isoforms was observed. As expected, there was a general inverse relationship between apo(a) isoform size and Lp(a) level. However, when groups with equivalent single-expressing apo(a) isoforms were studied, it was clear that although smaller isoforms were associated on average with higher levels, they were also associated with the greatest variability in level. After logarithmic transformation of Lp(a) data, the overall contribution of the apo(a) length polymorphism was calculated to be 38%. However, in subjects with apo(a) isoforms of </=20 kringle-4 (K-4) repeats, only 9% of the variability in Lp(a) concentration is explicable on the basis of the apo(a) length polymorphism. In those with apo(a) isoforms of >20 K-4 repeats, the corresponding contribution is 10%. We conclude that the contribution of the apo(a) isoform size to the control of plasma Lp(a) level is considerably lower than previously calculated, because the variability in plasma Lp(a) concentration is not uniform across the apo(a) size spectrum.
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Affiliation(s)
- A Gaw
- Department of Pathological Biochemistry, Royal Infirmary, University of Glasgow, UK
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Martín S, Ladona MG, Pedro-Botet J, Covas MI, Rubiés-Prat J. Differential expression of double-band apolipoprotein(a) phenotypes in healthy Spanish subjects detected by SDS-agarose immunoblotting. Clin Chim Acta 1998; 277:191-205. [PMID: 9853702 DOI: 10.1016/s0009-8981(98)00126-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A sodium dodecyl sulphate-agarose apolipoprotein(a) [apo(a)] phenotyping method was set up to attain accurate scanning densitometry of proteins. Serum samples from 99 healthy Spanish men were analysed and twenty-five different apo(a) isoforms (12 to 37 kringle 4 repeats) were detected. Double-band phenotypes accounted for 39.4% (n = 39) and three different patterns of protein expression were identified: pattern A (20.5% of double-band phenotyped samples) predominantly expressed the highest molecular weight isoform; pattern B (53.9%) mainly the lowest molecular weight isoform, and pattern AB (25.6%), expressed both isoforms equally. A significant linear association between expression pattern and lipoprotein(a) [Lp(a)] concentration > or = 0.30 g/l was observed. Single-band phenotyped samples (n = 60) were stratified according to apo(a) kringle 4 repeat categories and showed that 90% of isoforms < 20 K4 repeats had high Lp(a) concentrations (> or = 0.30 g/l), whereas isoforms with 20 to 24 or more than 24 kringle 4 repeats had Lp(a) concentrations > or = 0.30 g/l in 47% and 14%, respectively. A logistic regression model was fitted to test the association between apo(a) size, expression pattern and Lp(a) concentration. In this model, apo(a) isoform < 25 kringle 4 repeats was significantly associated with serum Lp(a) concentration > or = 0.30 g/l in both single and double-band phenotyped samples (odds ratio = 8.9, p < 0.001). In the latter, a differential expression pattern with respect to smaller size isoforms (pattern AB vs A) was significantly associated with Lp(a) concentration > or = 0.30 g/l (odds ratio = 17.97, P = 0.045). Heterogeneity in protein apo(a) size expressed according to kringle 4 repeat number could be categorized in heterozygous phenotypes as three patterns. When small-sized isoform was expressed (pattern B) or both isoforms were equally expressed (pattern AB), the probability of having Lp(a) > or = 0.30 g/l is higher.
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Affiliation(s)
- S Martín
- Unitat de Lipids i Epidemiologia Cardiovascular, IMIM, Universidad Autónoma de Barcelona, Spain
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45
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Ciccarese M, Tonolo G, Brizzi P, Secchi G, Garrucciu G, Spanedda M, Salis S, Calvia P, Asara A, Wong FK, Maioli M, Realdi G. Serum apolipoprotein(a) concentrations and Apo(a) phenotypes in patients with liver cirrhosis. Am J Gastroenterol 1998; 93:1505-9. [PMID: 9732933 DOI: 10.1111/j.1572-0241.1998.00471.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE The liver is the major site of apolipoprotein(a) synthesis, and an inverse correlation between the size of apolipoprotein(a) isoforms and its serum levels have been described. We evaluated the Apo(a) serum levels and its isoforms in patients with liver cirrhosis at different stages of the disease (Childe Turcotte classification), and during the characteristic phase of liver synthesis decline. METHODS We studied 84 patients with liver cirrhosis and 185 control subjects with normal liver function. RESULTS Apo(a) serum levels were significantly lower (p < 0.01) in cirrhotic patients and, after 24 months, six patients showing a change from class A to class B had a statistically significant decrease in Apo(a) concentrations (p = 0.0313). Moreover, our data showed an inversion of the small/large isoforms ratio in patient with cirrhosis in spite of the reduction in plasma concentration. CONCLUSION We showed a reduction of Apo(a) serum concentrations in a large number of patients with cirrhosis and, for the first time, during the characteristic phase of liver synthesis decline, confirming the liver as the major site of Apolipoprotein(a) synthesis. Moreover we showed in the cirrhotic patients that the normal correlation between Apo(a) isoforms and Apo(a) concentrations is not conserved and the low levels are not dependent upon a high prevalence of large isoforms.
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Affiliation(s)
- M Ciccarese
- Istituto di Clinica Medica, University of Sassari, Italy
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46
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47
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Abstract
Lipoproteins are spherical macromolecular complexes in which hydrophobic molecules of triglyceride and cholesteryl ester are enveloped within a monolayer of amphipathic molecules of phospholipids, free cholesterol, and apoproteins. The major lipoprotein classes include intestinally derived chylomicrons that transport dietary fats and cholesterol, hepatic-derived VLDL, IDL, and LDL that can be atherogenic, and hepatic- and intestinally derived HDL that are anti-atherogenic. Apoprotein B is necessary for the secretion of chylomicrons (apo B48) and VLDL, IDL, and LDL (apo B100). Post-translational regulation of the assembly of apo B-containing lipoproteins by core lipid availability seems to be the major mechanism for variations in secretion. Plasma levels of VLDL triglycerides are determined mainly by rates of secretion and LPL lipolytic activity; plasma levels of LDL cholesterol are determined mainly by the secretion of apo B100 into plasma, the efficacy with which VLDL are converted to LDL and by LDL receptor-mediated clearance. Regulation of HDL cholesterol levels is complex and is affected by rates of synthesis of its apoproteins, rates of esterification of free cholesterol to cholesteryl ester by LCAT, levels of triglyceride-rich lipoproteins and CETP-mediated transfer of cholesteryl esters from HDL, and clearance from plasma of HDL lipids and apoproteins. Normal lipoprotein transport is associated with low levels of triglycerides and LDL cholesterol and high levels of HDL cholesterol. When lipoprotein transport is abnormal, lipoproteins levels can change in ways that predispose individuals to atherosclerosis.
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Affiliation(s)
- H N Ginsberg
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York, USA
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48
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Murata M, Saito T, Takahashi S, Ichinose A. Plasma lipoprotein(a) levels are high in patients with central retinal artery occlusion. Thromb Res 1998; 91:169-75. [PMID: 9736419 DOI: 10.1016/s0049-3848(98)00082-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
High plasma lipoprotein(a) (Lp[a]) concentration is an independent risk factor for atherosclerosis and thrombosis. To study the implications of Lp(a) in central retinal artery occlusion (CRAO), we examined Lp(a) levels and molecular weights (MWs) of apolipoprotein(a) (apo(a)). Mean Lp(a) concentration was significantly higher in the cases with CRAO than in the controls. Lp(a) levels higher than 30 mg/dl were also more frequent in the CRAO cases than in the controls. Lp(a) concentrations correlated significantly with low-MW isoforms of apo(a). Impaired fibrinolysis and atherogenesis induced by Lp(a) may play a role in the pathophysiology of CRAO. Since high Lp(a) levels were reported in CRVO by other investigators, patients with central retinal vein occlusion (CRVO) were also examined for Lp(a). Although Lp(a) levels were higher in the CRVO cases than in the controls, the difference was not significant. Therefore, high Lp(a) levels may not be associated with venous thrombosis and/or embolism.
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Affiliation(s)
- M Murata
- Department of Molecular Pathological Biochemistry and Biology, Yamagata University School of Medicine, Japan
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49
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Rainwater DL, Haffner SM. Insulin and 2-hour glucose levels are inversely related to Lp(a) concentrations controlled for LPA genotype. Arterioscler Thromb Vasc Biol 1998; 18:1335-41. [PMID: 9714142 DOI: 10.1161/01.atv.18.8.1335] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this study we assessed the relationship of lipoprotein(a) [Lp(a)] with diabetes status and with measures of glucose and insulin in a population of Mexican Americans having a high prevalence of non-insulin-dependent diabetes mellitus (NIDDM). Because of enormous allelic diversity at LPA [the locus encoding the apo(a) protein] that directly influences Lp(a) concentrations, it was first necessary to adjust for the large effects of variation at LPA. We calculated residual Lp(a) concentration as the difference between observed and expected; expected Lp(a) concentration was based on information from all family members sharing each identical-by-descent (IBD) allele. We found significant effects of sex and age on residual Lp(a) concentrations that increased with age (P=0.0004) and in females (P=0.0034). Although diabetes status per se was not related to residual Lp(a) concentrations (P=0.097), we found that residual Lp(a) concentrations were inversely correlated with fasting insulin (P=0.0017) and with insulin (P=0.0028) and glucose (P=0.0429) concentrations measured 2 hours after a glucose challenge. Furthermore, significant inverse correlations with the 2 insulin measures were observed for a subgroup of nondiabetic individuals. Inclusion of 2 lipid measures (plasma concentrations of cholesterol and triglycerides) in the models showed that the correlations with insulin and glucose were independent of the relationship between Lp(a) concentrations and the lipid measures. Also, we determined the residual size for each apo(a) isoform by adjusting for the IBD isoform group average. Although not related to diabetes status, residual apo(a) isoform size was positively correlated with fasting insulin (P=0.0013) and with 2-hour glucose (P=0.0246) and 2-hour insulin (P=0.0182) concentrations. In addition, significant correlations for all 4 measures were found for the subgroup of nondiabetic individuals. Thus, the results demonstrate that glucose-intolerant individuals have significantly lower residual Lp(a) concentrations and a significant increase of residual apo(a) size.
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Affiliation(s)
- D L Rainwater
- Department of Genetics, Southwest Foundation for Biomedical Research, San Antonio, Tex 78245-0549, USA.
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Dahlén GH, Stenlund H. Lp(a) lipoprotein is a major risk factor for cardiovascular disease: pathogenic mechanisms and clinical significance. Clin Genet 1997; 52:272-80. [PMID: 9520117 DOI: 10.1111/j.1399-0004.1997.tb04344.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The results of two previous and two recent studies of middle-aged males and females are presented to exemplify the clinical importance of lipoprotein(a) (Lp(a)) as a risk factor for atherosclerosis and coronary heart disease. In these studies various conventional and recently suggested risk factors were included and different methods for Lp(a) quantification were used. Lp(a) was a significant risk factor in all four studies. In the recent prospective case-control study, Lp(a) and cholesterol were found to act synergistically and predict primary acute myocardial infarction in Swedish males. A cholesterol level above 6.5 mmol/l increased the risk of acute myocardial infarction if the Lp(a) level was above 200 mg/l. The plasma apo A-I level was a protective factor. In the other recent case-control study, an Lp(a) level above 500 mg/l was a highly significant risk factor in Black and White US women with myocardial infarction or advanced coronary artery disease in addition to low density lipoprotein cholesterol levels above 130 mg/dl. A high apo A-I level was a protective factor. In these studies no other factors tested reached significance in multivariate logistic regression analysis. A hypothetical association between high Lp(a) levels and intracellular infection with Chlamydia pneumoniae is discussed. The results suggest that the Lp(a) level is useful in identifying high-risk individuals. Lowering low density lipoprotein cholesterol below 100 mg/dl (<2.6 mmol/l) seems to be most important in both males and females with high-risk Lp(a) levels.
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Affiliation(s)
- G H Dahlén
- Department of Clinical Chemistry, University of Umeå, Sweden
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