2
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Donato LJ, Meeusen JW, Callanan H, Saenger AK, Jaffe AS. Advantages of the lipoprotein-associated phospholipase A2 activity assay. Clin Biochem 2015; 49:172-5. [PMID: 26365697 DOI: 10.1016/j.clinbiochem.2015.09.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 09/03/2015] [Accepted: 09/08/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVES Lipoprotein-associated phospholipase A2 (Lp-PLA2) is increased in circulation in patients at higher risk of coronary heart disease (CHD) events and stroke. Therefore, measurement of Lp-PLA2 can be used as an adjunct to traditional cardiovascular risk factors for identifying individuals at higher risk of cardiovascular events. Recently, a reagent for measuring Lp-PLA2 activity (diaDexus, San Francisco, CA) received FDA approval. Here we evaluate the assay performance of the Lp-PLA2 activity assay. METHODS Lp-PLA2 activity assay reagent performance was evaluated on an open user-defined channel on a Cobas 6000/c501 (Roche Diagnostics, Indianapolis, IN) using a 5-point calibration curve (0-400nmol/min/mL). Analytical performance was established for the following parameters: precision, linearity, accuracy, analytical sensitivity, analytical specificity, reference interval, reagent lot-to-lot comparison, specimen type, on-board reagent stability, and sample stability. RESULTS Assay limit of detection was determined to be 7.8nmol/min/mL with an average %CV of 2.8%. Precision studies revealed a coefficient of variation ≤1.6% between 79 and 307nmol/min/mL and accuracy was demonstrated between 4.8-368.7nmol/min/mL. Comparable results were generated in paired SST serum and EDTA plasma. No age association was found with Lp-PLA2 activity at the 95th percentile however a gender association was identified resulting in gender-specific 95th percentile limits in a healthy reference population. No bias was found when comparing results from several different lots of assay reagent. Lp-PLA2 activity results are extremely stable in both serum and EDTA plasma under refrigerate and frozen storage conditions up to 31days. CONCLUSIONS Lp-PLA2 activity assay displays accurate and precise performance characteristics on the Cobas c501 platform. The assay performance is significantly improved over the predecessor immunoassay allowing for adoption of Lp-PLA2 activity in clinical practice.
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Affiliation(s)
- Leslie J Donato
- Department of Laboratory Medicine and Pathology Mayo Clinic, Rochester, MN 55905, United States.
| | - Jeffrey W Meeusen
- Department of Laboratory Medicine and Pathology Mayo Clinic, Rochester, MN 55905, United States
| | - Heidi Callanan
- Department of Laboratory Medicine and Pathology Mayo Clinic, Rochester, MN 55905, United States
| | - Amy K Saenger
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, United States
| | - Allan S Jaffe
- Department of Laboratory Medicine and Pathology Mayo Clinic, Rochester, MN 55905, United States; Division of Cardiology, Mayo Clinic, Rochester, MN 55905, United States
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3
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Chu AY, Guilianini F, Grallert H, Dupuis J, Ballantyne CM, Barratt BJ, Nyberg F, Chasman DI, Ridker PM. Genome-Wide Association Study Evaluating Lipoprotein-Associated Phospholipase A
2
Mass and Activity at Baseline and After Rosuvastatin Therapy. ACTA ACUST UNITED AC 2012; 5:676-85. [DOI: 10.1161/circgenetics.112.963314] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Background—
Lipoprotein-associated phospholipase A
2
(Lp-PLA
2
) is a proinflammatory enzyme bound to low-density lipoprotein cholesterol and other circulating lipoproteins. Two measures of Lp-PLA
2
, mass and activity, are associated with increased cardiovascular risk. Data are sparse regarding genetic determinants of Lp-PLA
2
mass and activity, and no prior data are available addressing genetic determinants of statin-induced changes for this proinflammatory biomarker.
Methods and Results
—
We performed a genome-wide association study of Lp-PLA
2
mass and activity at baseline and after 12 months of rosuvastatin therapy (20 mg/d) among 6851 participants of European ancestry from the Justification for Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) and performed replication in a meta-analysis of 13 664 participants from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium. Novel associations were identified and replicated at
MS4A4E
and
TMEM49
for baseline Lp-PLA
2
activity with genome-wide significant joint
P
values (
P
=2.0×10
−11
and
P
=2.9×10
−9
, respectively). In addition, genome-wide associations (
P
<5×10
−8
) were identified and replicated for baseline Lp-PLA
2
mass at
CETP
and for Lp-PLA
2
activity at the
APOC1-APOE
and
PLA2G7
loci. Among 2673 statin-allocated participants, both Lp-PLA
2
mass and activity were reduced by >30% and low-density lipoprotein cholesterol by 50% after 12 months of statin therapy (
P
<0.001 for both). Variants in
ABCG2
and
LPA
were associated with change in statin-induced Lp-PLA
2
activity at genome-wide significance but were substantially attenuated after adjustment for statin-induced changes in lipid levels.
Conclusions—
Genome-wide significant associations at
MS4A4E
and
TMEM49
may reflect novel influences on circulating levels of Lp-PLA
2
activity. In addition, genome-wide significant associations with rosuvastatin-induced change in Lp-PLA
2
activity were observed in
ABCG2
and
LPA
, likely because of their impact on statin-induced low-density lipoprotein cholesterol lowering.
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Affiliation(s)
- Audrey Y. Chu
- From the Center for Cardiovascular Disease Prevention, the Division of Preventive Medicine (A.Y.C., F.G., D.I.C., P.M.R.), Division of Genetics (D.I.C.), and Division of Cardiology (P.M.R.), Brigham and Women’s Hospital, Boston, MA; Helmholtz ZentrumMünchen, German Research Center for Environmental Health, Research Unit of Molecular Epidemiology, Neuherberg, Germany (H.G.); National Heart, Lung, and Blood Institute’s and Boston University’s Framingham Heart Study, Framingham, MA (J.D.); Department
| | - Franco Guilianini
- From the Center for Cardiovascular Disease Prevention, the Division of Preventive Medicine (A.Y.C., F.G., D.I.C., P.M.R.), Division of Genetics (D.I.C.), and Division of Cardiology (P.M.R.), Brigham and Women’s Hospital, Boston, MA; Helmholtz ZentrumMünchen, German Research Center for Environmental Health, Research Unit of Molecular Epidemiology, Neuherberg, Germany (H.G.); National Heart, Lung, and Blood Institute’s and Boston University’s Framingham Heart Study, Framingham, MA (J.D.); Department
| | - Harald Grallert
- From the Center for Cardiovascular Disease Prevention, the Division of Preventive Medicine (A.Y.C., F.G., D.I.C., P.M.R.), Division of Genetics (D.I.C.), and Division of Cardiology (P.M.R.), Brigham and Women’s Hospital, Boston, MA; Helmholtz ZentrumMünchen, German Research Center for Environmental Health, Research Unit of Molecular Epidemiology, Neuherberg, Germany (H.G.); National Heart, Lung, and Blood Institute’s and Boston University’s Framingham Heart Study, Framingham, MA (J.D.); Department
| | - Josée Dupuis
- From the Center for Cardiovascular Disease Prevention, the Division of Preventive Medicine (A.Y.C., F.G., D.I.C., P.M.R.), Division of Genetics (D.I.C.), and Division of Cardiology (P.M.R.), Brigham and Women’s Hospital, Boston, MA; Helmholtz ZentrumMünchen, German Research Center for Environmental Health, Research Unit of Molecular Epidemiology, Neuherberg, Germany (H.G.); National Heart, Lung, and Blood Institute’s and Boston University’s Framingham Heart Study, Framingham, MA (J.D.); Department
| | - Christie M. Ballantyne
- From the Center for Cardiovascular Disease Prevention, the Division of Preventive Medicine (A.Y.C., F.G., D.I.C., P.M.R.), Division of Genetics (D.I.C.), and Division of Cardiology (P.M.R.), Brigham and Women’s Hospital, Boston, MA; Helmholtz ZentrumMünchen, German Research Center for Environmental Health, Research Unit of Molecular Epidemiology, Neuherberg, Germany (H.G.); National Heart, Lung, and Blood Institute’s and Boston University’s Framingham Heart Study, Framingham, MA (J.D.); Department
| | - Bryan J. Barratt
- From the Center for Cardiovascular Disease Prevention, the Division of Preventive Medicine (A.Y.C., F.G., D.I.C., P.M.R.), Division of Genetics (D.I.C.), and Division of Cardiology (P.M.R.), Brigham and Women’s Hospital, Boston, MA; Helmholtz ZentrumMünchen, German Research Center for Environmental Health, Research Unit of Molecular Epidemiology, Neuherberg, Germany (H.G.); National Heart, Lung, and Blood Institute’s and Boston University’s Framingham Heart Study, Framingham, MA (J.D.); Department
| | - Fredrik Nyberg
- From the Center for Cardiovascular Disease Prevention, the Division of Preventive Medicine (A.Y.C., F.G., D.I.C., P.M.R.), Division of Genetics (D.I.C.), and Division of Cardiology (P.M.R.), Brigham and Women’s Hospital, Boston, MA; Helmholtz ZentrumMünchen, German Research Center for Environmental Health, Research Unit of Molecular Epidemiology, Neuherberg, Germany (H.G.); National Heart, Lung, and Blood Institute’s and Boston University’s Framingham Heart Study, Framingham, MA (J.D.); Department
| | - Daniel I. Chasman
- From the Center for Cardiovascular Disease Prevention, the Division of Preventive Medicine (A.Y.C., F.G., D.I.C., P.M.R.), Division of Genetics (D.I.C.), and Division of Cardiology (P.M.R.), Brigham and Women’s Hospital, Boston, MA; Helmholtz ZentrumMünchen, German Research Center for Environmental Health, Research Unit of Molecular Epidemiology, Neuherberg, Germany (H.G.); National Heart, Lung, and Blood Institute’s and Boston University’s Framingham Heart Study, Framingham, MA (J.D.); Department
| | - Paul M. Ridker
- From the Center for Cardiovascular Disease Prevention, the Division of Preventive Medicine (A.Y.C., F.G., D.I.C., P.M.R.), Division of Genetics (D.I.C.), and Division of Cardiology (P.M.R.), Brigham and Women’s Hospital, Boston, MA; Helmholtz ZentrumMünchen, German Research Center for Environmental Health, Research Unit of Molecular Epidemiology, Neuherberg, Germany (H.G.); National Heart, Lung, and Blood Institute’s and Boston University’s Framingham Heart Study, Framingham, MA (J.D.); Department
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4
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Cook NR, Paynter NP, Manson JE, Martin LW, Robinson JG, Wassertheil-Smoller S, Ridker PM. Clinical utility of lipoprotein-associated phospholipase A₂ for cardiovascular disease prediction in a multiethnic cohort of women. Clin Chem 2012; 58:1352-63. [PMID: 22859728 DOI: 10.1373/clinchem.2012.188870] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Findings regarding the association of lipoprotein-associated phospholipase A₂ (Lp-PLA2) activity and mass with incident cardiovascular disease (CVD) have been inconsistent, and their role in risk prediction is uncertain. METHODS A case-cohort sample from the Women's Health Initiative Observational Study (WHI-OS) comprised 1821 CVD cases and a reference subcohort of 1992 women. We used Cox regression models with inverse sampling weights to assess the association of Lp-PLA2 mass and activity with CVD (myocardial infarction, stroke, and CVD mortality). RESULTS Subcohort means were 184.3 mmol/min/mL for Lp-PLA2 activity and 499.2 μg/L for Lp-PLA2 mass, with 99% having mass above 200 μg/L, the clinically recommended cut point. Both activity and mass were positively associated with incident CVD in age- and race/ethnicity-adjusted analyses. Following adjustment according to CVD risk factors, the association with activity became null (hazard ratio = 1.02 for top vs bottom quartile, 95% CI = 0.79-1.33, P for trend = 0.65), but the association with mass remained (hazard ratio = 1.84, 95% CI = 1.45-2.34, P for trend < 0.0001). In contrast to blood pressure, HDL, and hsCRP, reclassification statistics for Lp-PLA2 mass did not suggest improvement for overall CVD after full adjustment. CONCLUSIONS In the WHI-OS Lp-PLA2 mass, but not activity, was independently associated with CVD. However, model fit did not significantly improve with Lp-PLA2 mass, and assay calibration remains a clinical concern.
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Affiliation(s)
- Nancy R Cook
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02215, USA.
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5
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Rosenson RS, Stafforini DM. Modulation of oxidative stress, inflammation, and atherosclerosis by lipoprotein-associated phospholipase A2. J Lipid Res 2012; 53:1767-82. [PMID: 22665167 DOI: 10.1194/jlr.r024190] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), also known as platelet-activating factor acetylhydrolase (PAF-AH), is a unique member of the phospholipase A(2) superfamily. This enzyme is characterized by its ability to specifically hydrolyze PAF as well as glycerophospholipids containing short, truncated, and/or oxidized fatty acyl groups at the sn-2 position of the glycerol backbone. In humans, Lp-PLA(2) circulates in active form as a complex with low- and high-density lipoproteins. Clinical studies have reported that plasma Lp-PLA(2) activity and mass are strongly associated with atherogenic lipids and vascular risk. These observations led to the hypothesis that Lp-PLA(2) activity and/or mass levels could be used as biomarkers of cardiovascular disease and that inhibition of the activity could offer an attractive therapeutic strategy. Darapladib, a compound that inhibits Lp-PLA(2) activity, is anti-atherogenic in mice and other animals, and it decreases atherosclerotic plaque expansion in humans. However, disagreement continues to exist regarding the validity of Lp-PLA(2) as an independent marker of atherosclerosis and a scientifically justified target for intervention. Circulating Lp-PLA(2) mass and activity are associated with vascular risk, but the strength of the association is reduced after adjustment for basal concentrations of the lipoprotein carriers with which the enzyme associates. Genetic studies in humans harboring an inactivating mutation at this locus indicate that loss of Lp-PLA(2) function is a risk factor for inflammatory and vascular conditions in Japanese cohorts. Consistently, overexpression of Lp-PLA(2) has anti-inflammatory and anti-atherogenic properties in animal models. This thematic review critically discusses results from laboratory and animal studies, analyzes genetic evidence, reviews clinical work demonstrating associations between Lp-PLA(2) and vascular disease, and summarizes results from animal and human clinical trials in which administration of darapladib was tested as a strategy for the management of atherosclerosis.
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9
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Saenger AK, Christenson RH. Stroke biomarkers: progress and challenges for diagnosis, prognosis, differentiation, and treatment. Clin Chem 2009; 56:21-33. [PMID: 19926776 DOI: 10.1373/clinchem.2009.133801] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND Stroke is a devastating condition encompassing a wide range of pathophysiological entities that include thrombosis, hemorrhage, and embolism. Current diagnosis of stroke relies on physician clinical examination and is further supplemented with various neuroimaging techniques. A single set or multiple sets of blood biomarkers that could be used in an acute setting to diagnosis stroke, differentiate between stroke types, or even predict an initial/reoccurring stroke would be extremely valuable. CONTENT We discuss the current classification, diagnosis, and treatment of stroke, focusing on use of novel biomarkers (either solitary markers or multiple markers within a panel) that have been studied in a variety of clinical settings. SUMMARY The current diagnosis of stroke remains hampered and delayed due to lack of a suitable mechanism for rapid (ideally point-of-care), accurate, and analytically sensitive biomarker-based testing. There is a clear need for further development and translational research in this area. Potential biomarkers identified need to be transitioned quickly into clinical validation testing for further evaluation in an acute stroke setting; to do so would impact and improve patient outcomes and quality of life.
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Affiliation(s)
- Amy K Saenger
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA.
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