Processed B-type natriuretic peptide is a biomarker of postinterventional restenosis in ischemic heart disease.
B-type natriuretic peptide (BNP) is a bioactive peptide that counteracts hemodynamic stress induced by various pathologic conditions through actions such as natriuresis and vasodilation (7, 8). BNP is released into the circulation in large amounts during heart failure, allowing its measured circulating concentrations to be used in diagnosis of this condition (7-10). BNP concentrations are also moderately increased in ischemic heart disease, but their diagnostic potential in this condition is less well explored (11, 12). BNP is synthesized as a propeptide, preproBNP(1-134), that undergoes rapid removal of a 26-amino acid (26-aa) signal peptide, resulting in the formation of a 108-aa prohormone, proBNP(1-108). Subsequently, proBNP(1108) is cleaved by proteolytic enzymes furin and corin to release 2 processed peptides, the biologically inert 76-aa amino-terminal portion NT-proBNP(1-76) and the biologically active 32-aa molecule BNP(1-32) [see (13) for review]. Recently, other processed (proteolytic) forms of BNP [e.g., BNP(3-32), BNP(4-32), and BNP(5-32)] have been shown to exist in the circulation, but the clinical implications of these BNP peptides remain poorly understood (14-16).
Protein processing via proteases is central to the metabolism of many peptides. In the heart, myofilament proteins such as troponin have been shown to be processed under ischemic conditions, which may lead to myocardial contractile dysfunction through effects on calcium-dependent muscle contraction responses (17). Measurement of processed troponin peptides released into the circulation from damaged and/or necrotic cardiomyocytes has been suggested to be of potential use in risk stratification of patients with coronary syndromes (18). There are other clinical situations in which processed proteins/peptides serve as diagnostic biomarkers, such as the use of amyloid [beta] (A[beta]) peptides in Alzheimer disease. The Ap peptides generated through sequential proteolytic processing of the amyloid precursor protein by 2 enzymes, [beta]-secretase and [gamma]-secretase, have been shown to be reflective of Alzheimer disease pathophysiology [see (19) for review], with lower concentrations of A[beta]42 (as a ratio to A[beta]40) being associated with cognitive decline (20). Protein processing is also the target of therapeutic interventions such as use of dipeptidyl-peptidase IV (DPP-IV) inhibitors, which inhibit protease processing of glucagonlike peptide 1 and glucose-dependent insulinotropic peptide in treatment of diabetes (21-23). In the present study, we hypothesized that processing of BNP might have value as a diagnostic biomarker for ischemic heart disease and found that it is associated with restenosis.
PATIENTS AND PROTOCOLS
Between June 2007 and November 2011, we examined a total of 105 consecutive consenting patients with mildly increased BNP concentrations who underwent PCI with follow-up coronary angiography (CAG) approximately 6 months after the procedure. Patients were excluded if they had acute myocardial infarction, unstable angina pectoris, congestive heart failure, or chronic renal failure [serum creatinine >2.0 mg/dL (>176.8 [micro]mol/L)], because of confounding effects on BNP concentrations. Patients with BNP concentrations >200 pg/mL were excluded because of possible confounding heart failure and other heart disease as described. Coronary angiograms were assessed by 2 experienced angiographers who were unaware of the results of analysis of BNP forms as described herein. Significant stenosis was defined as >50% narrowing of the coronary artery as determined by quantitative coronary angiography according to American Heart Association guidelines (24).
Blood samples were obtained at time of follow-up CAG after PCI. Samples were transferred immediately into tubes containing EDTA-2Na and aprotinin (Neotube NP-EA0305, Nipro Corp.) and kept at 4 [degrees]C until plasma was separated by centrifugation within 6 h, and then stored at -80 [degrees]C until analysis. We measured plasma total BNP concentrations using a conventional enzyme immunoassay (Rapidpia, Sekisui Medical) (25).
Nonstenotic concentrations of BNP(5-32)/BNP(3-32) ratio and BNP in this study were measured using blood samples from consenting patients diagnosed to not have coronary stenosis on diagnostic CAG (n = 66).
This study was approved by the ethics committee of the Graduate School of Medicine, the University of Tokyo, and written informed consent was obtained from each patient.
DETECTION OF BNP FORMS
We developed a mass spectrometry-based immunoassay (MS-IA) procedure (as described in detail in Supplemental Text, which accompanies the online version of this article at http://www.clinchem.org/content/vol59/issue9) to measure circulating BNP peptides. Briefly, after capturing BNP peptides with an antibody raised against the ring region of BNP(1-32) (an antibody routinely used in a commercial BNP assay available from Shionogi) (26) bound to magnetic beads, captured BNP peptides were eluted and then detected by MALDI-TOF mass spectrometry (Axima CFR Plus and Axima Confidence, Shimadzu Corp.). Results of coronary angiograms were not made available at time of measurement. The analytical measurement range of the assay was approximately 20-3000 pg/mL. Within-run reproducibility as a measure of analytic precision showed a CV between 7.4% and 8.8% (see online Supplemental Table 1).
We analyzed continuous data, expressed as median with interquartile ranges, by the Wilcoxon rank-sum test to compare medians of values and discrete variables with the Fisher exact test. We used multivariate logistic regression analysis to determine variables associated with restenosis. For multivariable models, a stepwise variable selection was performed starting with all of the variables from the univariate model that had a P value of <0.2. The final model was generated with backward stepwise logistic regression (P to leave: 0.05) (note that a forward stepwise model gave the same results). The final model included only variables that had a P value of <0.05. We determined ROC curves, standard diagnostic sensitivity and specificity, likelihood ratios, and predictive value to evaluate diagnostic performance. All statistical analyses were performed with JMP version 8.0.2 (SAS Institute) and MedCalc version 12.3 (MedCalc Software). A 2-tailed P < 0.05 was considered statistically significant.
MASS SPECTROMETRY IMMUNOASSAY FOR DETECTION OF CIRCULATING PROCESSED FORMS OF BNP
Because currently available conventional immunoassays cannot discriminate individual processed BNP peptides, we developed a mass spectrometry-based detection method combined with immunocapture by commercial anti-BNP antibodies to detect processed forms of BNP in the circulation, as shown in Fig. 1A. The assay consisted of 2 steps: the first involved immunocapture in which all forms of circulating BNP were captured by anti-BNP monoclonal antibody bound to magnetic beads; the second step involved analysis by mass spectrometry in which captured BNP was eluted from the magnetic beads and analyzed with MALDI-TOF mass spectrometry (further details on the methodology can be found in online Supplemental Text 1).
By use of this method, we detected 3 major forms of BNP: BNP(3-32), BNP(4-32), and BNP(5-32), numbered as amino acids from the amino-terminal end of the 32-amino acid BNP (Fig. 1B). Of the 3 forms, BNP(5-32) was pursued further, as initial measurements showed reduced concentrations of this peptide in patients with restenosis (Fig. 1B). An index peptide to serve as an internal control to quantify concentrations of BNP(5-32) was needed, but because the full-length peptide, BNP(1-32), was detected in only minute amounts in contrast to BNP(3-32), which was present at higher stable concentrations, an arbitrary index of the ratio of BNP(5-32) to BNP(3-32) was used for further analytical purposes.
DIAGNOSTIC IMPLICATIONS OF PROCESSED FORMS OF BNP
Of the 105 patients enrolled (Table 1 and online Supplemental Table 2), 63% were male (n = 66) and the median age was 70 years [interquartile range (IQR) 6376]. Comorbid coronary risk factors included hypertension in 90 cases (86%), diabetes mellitus in 65 cases (62%), and smoking in 71 cases (68%). Serum creatinine was 0.83 mg/dL (IQR 0.70-0.94) [73.4 [micro]mol/L (IQR 61.4-83.1)]; C-reactive protein (CRP) was 0.5 mg/L (IQR 0.3-1.2); HDL cholesterol was 53.2 mg/dL (IQR 44.5-68.6) [1.4 mmol/L (IQR 1.2-1.8)]; LDL cholesterol was 88.5 mg/dL (IQR 78.3-103.5) [2.3 mmol/L (IQR 2.0-2.7)]; and BNP was 51.9 pg/mL (IQR 37.5-83.7). 75% of patients (79 cases) were treated with drug-eluting stents, and angiographic outcome at follow-up CAG showed 22 cases of defined restenosis (21% overall, 13% for drug-eluting stents).
The BNP(5-32)/BNP(3-32) ratio was significantly lower in patients with restenosis at time of follow-up CAG (restenosis 1.19, IQR 1.11-1.34, n = 22, vs without restenosis 1.43, IQR 1.22-1.61, n = 83; P < 0.001) (Table 1 and Fig. 2A). Notably, total BNP concentrations as measured with a standard commercial immunoassay did not show association with restenosis (Table 1 and Fig. 2B). Reference median concentrations of BNP and BNP(5-32)/BNP(3-32) ratio in the present study were 57.5 pg/mL (IQR 39.5-94.2, n = 66) and 1.43 (IQR 1.28-1.72, n = 66), respectively.
ROC analysis of the diagnostic accuracy of the BNP(5-32)/BNP(3-32) ratio for those with presence of restenosis showed an area under the curve of 0.775 (95% CI 0.683-0.851), and the optimal cutoff value for discrimination of stenosis was 1.41 (sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio were 91%, 54%, 1.99, and 0.17, respectively) (see online Supplemental Table 3 and Supplemental Fig. 1). Sensitivity and specificity as well as negative and positive likelihood ratios in addition to positive and negative predictive values are shown in online Supplemental Table S3. Of interest, a negative likelihood ratio of <0.1 allowing for reliable rule-out (27) was attained at a ratio of 1.52, with both sensitivity and negative predictive value of 100%. Thus, measuring BNP processed forms as the BNP(5-32)/BNP(3-32) ratio had diagnostic value for ruling out restenosis.
We used univariate and multivariate analyses to examine the association of the BNP(5-32)/BNP(3-32) ratio with restenosis, taking into account the measured concentrations of other laboratory blood tests (total BNP, serum creatinine, CRP, ratio of total cholesterol to HDL cholesterol, total cholesterol, HDL cholesterol, triglycerides, and LDL cholesterol), risk factors (age, sex, hypertension, diabetes mellitus, smoking, use of lipid-lowering agents, and antihypertensive treatment), systolic and diastolic blood pressure, lesion length, and drug-eluting stent use for PCI. The BNP(532)/BNP(3-32) ratio [odds ratio (OR) 0.63; 95% CI 0.45-0.83; P < 0.001] and failure to use a drug-eluting stent (OR 4.20; 95% CI 1.40-12.99; P = 0.011) were significantly and independently associated with restenosis (Table 2). OR analysis showed that there was a 1.59-fold reduction in likelihood for restenosis with each 0.1 U increase in the BNP(5-32)/BNP(3-32) ratio.
Peptide processing has become increasingly recognized as important not only in metabolism of peptides but also in regulation of various pathologies, particularly since peptide processing has become the target of therapeutic intervention with pharmaceutical development of protease inhibitors in treatment of disease [e.g., DPP-IV inhibitors (22, 23)]. Recent studies have also focused on the possible exploitation of peptide processing in diagnosis of Alzheimer disease (20) and a potential role in ischemic heart disease (17, 18). In the present study, we focused on the bioactive cardiac hormone BNP, whose circulating concentrations are reflective of pathogenic activity and have been clinically used for diagnostic purposes, and showed that its processed forms are strongly associated with the condition of restenosis in ischemic heart disease. Methods to measure these peptide forms were developed using mass spectrometry-based detection combined with immunocapture, because conventional immunoassay methods are not able to discriminate the different forms. Our initial experience shows that measurement of BNP processing with this method is of potential use to diagnose restenosis.
We found that 3 major processed forms of circulating BNP--BNP(3-32), BNP(4-32), and BNP(532)--in addition to minute amounts of full-length BNP(1-32), were those primarily detected in the circulation in ischemic heart disease. Markedly lower concentrations of BNP(5-32) were seen in patients with restenosis at time of follow-up CAG. OR analysis showed that there was a 1.59-fold reduction in likelihood for presence of restenosis with each 0.1 U increase in the BNP(5-32)/BNP(3-32) ratio. Importantly, this ratio of the concentrations of processed forms of BNP was to be found useful as a new biomarker to rule out the presence of restenosis at cutoff concentrations of 1.52.
Our results suggest that processed forms of BNP, especially BNP(5-32), may reflect the pathophysiological process involved in restenosis. BNP is synthesized as preproBNP(1-134), which results in proBNP(1108) after the removal of a 26-aa signal peptide. ProBNP(1-108) is cleaved to a biologically inactive amino-terminal NT-proBNP(1-76) and active BNP(1-32) (13). A cardiac transmembrane serine protease, corin, and a ubiquitous serine protease, furin, are currently proposed as possible convertases (16, 28, 29). Recently, other processed forms of BNP, including BNP(3-32), BNP(4-32), and BNP(5-32), have been detected in plasma from heart failure patients in the presence of protease inhibitors benzamidine (as a trypsin, plasmin, thrombin inhibitor) and 4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride (as an inhibitor for serine protease such as DPP IV) to minimize the effect of protease degradation (15). Of the 3 processed forms of BNP, BNP(3-32) has been reported to be processed from BNP(1-32) by DPP-IV (14). BNP(4-32) has been reported to be processed by corin from proBNP, not from BNP(1-32) (16). Additionally, BNP(5-32) has been reported to be processed possibly from BNP(1-32) by neutral endopeptidase (30), but another study has reported that BNP(1-32) is resistant to neutral endopeptidase-mediated cleavage (14). Further, a recent study has reported that human proBNP injected into rats is processed into BNP(5-32) (31), thus indicating that BNP(5-32) maybe processed by an unknown protease in rats. Thus, the underlying pathologic mechanisms of BNP processing are thought to involve the combined actions of membrane-bound-type protease(s) such as neutral endopeptidases and dipeptidyl peptidases, but the precise underlying mechanisms of action are not understood. Pathogenic regulation of peptidase activity in disease states likely defines the proportion of BNP forms present in the circulation, and will be a topic of further investigation in the future.
Other attempts including some by our group to develop biomarkers of restenosis by use of interleukin-6 (32), oxidized LDL cholesterol markers (33), LDL cholesterol (34), HDL cholesterol (35), CRP (36-38), adiponectin (39), and their combinations have not proven clinically useful. Clinical algorithms also are not reliable (4, 5). Reduced relative concentrations of BNP(5-32), as measured with an analytical ratio of BNP(5-32)/BNP(3-32), were found to be strongly associated with presence of restenosis in our cross-sectional study. To our knowledge, diagnostic performance of the magnitude described in the present study has not been achieved by any other biomarker to date. Importantly, a rule-out biomarker has not been available for this condition to assist in risk stratification of patients.
The described biomarker might aid in identifying patients with less risk of restenosis after a PCI procedure. A tool for noninvasive identification of patients without restenosis after a PCI procedure would be helpful to reduce the burden of performing routine follow-up CAG. It would also be of merit in those settings in which follow-up CAG is not routinely done but is reserved as a tool to assist in ruling out the presence of restenosis when assessing patients with ambiguous chest pain after PCI. It is important to note that restenosis had been generally thought to be associated with relatively benign outcome, but recent evidence suggests that it is associated with myocardial damage and adverse clinical outcome (30% to 60% present with acute coronary syndrome, 5% present with ST-elevation myocardial infarction) [see (40) for review]. Therefore, given this need to identify patients at risk for restenosis, a noninvasive biomarker would be a welcome tool in management of the condition.
Longitudinal studies to determine the prognostic value of processed forms of BNP and clinical studies to address the association of these novel biomarkers with coronary events will be of further interest and are presently ongoing. The limitations of the current study include the need for further large-scale studies at multiple centers to validate the present findings. Additionally, there is need for studies that explore combined use of clinical algorithms with this and possibly other biomarkers to more accurately assess risk of restenosis. Further modification of this technology will be necessary to make this method or its derivatives more widely available for patient care.
In summary, we provide our initial experience with a newly developed method to measure processed forms of BNP as a biomarker for risk assessment in patients undergoing PCI for ruling out restenosis.
Author Contributions: All authors confirmed they have contributed to the intellectual content of this paper and have met the following 3 requirements: (a) significant contributions to the conception and design, acquisition of data, oranalysis and interpretation of data; (b) drafting or revising the article for intellectual content; and (c) final approval of the published article.
Authors' Disclosures or Potential Conflicts of Interest: Upon manuscript submission, all authors completed the author disclosure form. Disclosures and/or potential conflicts of interest:
Employment or Leadership: H. Fujimoto, Shimadzu Corporation.
Consultant or Advisory Role: None declared.
Stock Ownership: None declared.
Honoraria: None declared.
Research Funding: T. Suzuki, research grants from the Ministry of Health, Labour and Welfare of Japan for Research on Medical Device Development and for Research on Biological Markers for New Drug Development; Grants-in-Aid for Scientific Research in Priority Areas (B)(23390204) and for Translational Systems Biology and Medicine Initiative (TSBMI) from the Ministry of Education, Culture, Sports, Science and Technology of Japan; and the Japan Society for the Promotion of Science through its Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program); R. Nagai, Japan Society for the Promotion of Science through its Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program).
Expert Testimony: None declared.
Patents: H. Fujimoto, WO2010/023749; T. Suzuki, WO2010/023749.
Role of Sponsor: The funding organizations played no role in the design of study, choice of enrolled patients, review and interpretation of data, or preparation or approval of manuscript.
Acknowledgments: The authors thank Shionogi & Co. (Osaka, Japan) for kindly providing monoclonal BNP antibody (KY-hBNP II).
(1.) Moses JW, Leon MB, Popma JJ, Fitzgerald PJ, Holmes DR, O'Shaughnessy C, et al. Sirolimuseluting stents versus standard stents in patients with stenosis in a native coronary artery. N Engl J Med 2003; 349:1315-23.
(2.) Butany J, Carmichael K, Leong SW, Collins MJ. Coronary artery stents: identification and evaluation. J Clin Pathol 2005; 58:795-804.
(3.) Jukema JW, Verschuren JJ, Ahmed TA, Quax PH. Restenosis after PCI. Part 1: pathophysiology and risk factors. Nat Rev Cardiol 2012; 9:53-62.
(4.) Agema WR, Monraats PS, Zwinderman AH, De
Winter RJ, Tio RA, Doevendans PA, et al. Current PTCA practice and clinical outcomes in the Netherlands: the real world in the pre-drugeluting stent era. Eur Heart J 2004; 25:1 163-70.
(5.) Garg S, Serruys PW. Coronary stents: current status. J Am Coll Cardiol 2010; 56:S1-42.
(6.) Stolker JM, Kennedy KF, Lindsey JB, Marso SP, Pencina MJ, Cutlip DE, et al. Predicting restenosis of drug-eluting stents placed in real-world clinical practice: derivation and validation of a risk model from the EVENT registry. Circ Cardiovasc Interv 2010; 3:327-34.
(7.) Levin ER, Gardner DG, Samson WK. Natriuretic peptides. N Engl J Med 1998; 339:321-8.
(8.) Suzuki T, Yamazaki T, Yazaki Y. The role of the natriuretic peptides in the cardiovascular system. Cardiovasc Res 2001; 51:489-94.
(9.) Maisel AS, Krishnaswamy P, Nowak RM, McCord J, Hollander JE, Duc P, et al. Rapid measurement of B-type natriuretic peptide in the emergency diagnosis of heart failure. N Engl J Med 2002; 347:161-7.
(10.) Clerico A, Emdin M. Diagnostic accuracy and prognostic relevance of the measurement of car diac natriuretic peptides: a review. Clin Chem 2004; 50:33-50.
(11.) Morrow DA, de Lemos JA, Sabatine MS, Murphy SA, Demopoulos LA, DiBattiste PM, et al. Evaluation of B-type natriuretic peptide for risk assessment in unstable angina/non-ST-elevation myocardial infarction: B-type natriuretic peptide and prognosis in TACTICS-TIMI 18. J Am Coll Cardiol 2003; 41:1264-72.
(12.) Sabatine MS, Morrow DA, de Lemos JA, Omland T, Desai MY, Tanasijevic M, et al. Acute changes in circulating natriuretic peptide levels in relation to myocardial ischemia. J Am Coll Cardiol 2004; 44:1988-95.
(13.) Goetze JP. B-type natriuretic peptide: from posttranslational processing to clinical measurement. Clin Chem 2012; 58:83-91.
(14.) Brandt I, Lambeir AM, Ketelslegers JM, Vanderheyden M, Scharpe S, De Meester I. Dipeptidylpeptidase IV converts intact B-type natriuretic peptide into its des-SerPro form. Clin Chem 2006; 52:82-7.
(15.) Niederkofler EE, Kiernan UA, O'Rear J, Menon S, Saghir S, Protter AA, et al. Detection of endogenous B-type natriuretic peptide at very low concentrations in patients with heart failure. Circ Heart Fail 2008; 1:258-64.
(16.) Semenov AG, Tamm NN, Seferian KR, Postnikov AB, Karpova NS, Serebryanaya DV, et al. Processing of pro-B-type natriuretic peptide: furin and corin as candidate convertases. Clin Chem 2010; 56:1166-76.
(17.) Van Eyk JE, Powers F, Law W, Larue C, Hodges RS, Solaro RJ. Breakdown and release of myofilament proteins during ischemia and ischemia/ reperfusion in rat hearts: identification of degradation products and effects on the pCa-force relation. Circ Res 1998; 82:261-71.
(18.) McDonough JL, Labugger R, Pickett W, Tse MY, MacKenzie S, Pang SC, et al. Cardiac troponin I is modified in the myocardium of bypass patients. Circulation 2001; 103:58-64.
(19.) Holtzman DM, Morris JC, Goate AM. Alzheimer's disease: the challenge of the second century. Sci Transl Med 2011; 3:77sr1.
(20.) Yaffe K, Weston A, Graff-Radford NR, Satterfield S, Simonsick EM, Younkin SG, et al. Association of plasma beta-amyloid level and cognitive reserve with subsequent cognitive decline. JAMA 2011; 305:261-6.
(21.) Lambeir AM, Durinx C, Scharpe S, De Meester I. Dipeptidyl-peptidase IV from bench to bedside: an update on structural properties, functions, and
clinical aspects of the enzyme DPP IV. Crit Rev Clin Lab Sci 2003; 40:209-94.
(22.) Drucker DJ. Therapeutic potential of dipeptidyl peptidase IV inhibitors for the treatment of type 2 diabetes. Expert Opin Investig Drugs 2003; 12:87100.
(23.) Holst JJ. Implementation of GLP-1 based therapy of type 2 diabetes mellitus using DPP-IV inhibitors. Adv Exp Med Biol 2003; 524:263-79.
(24.) Ryan TJ, Faxon DP, Gunnar RM, Kennedy JW, King SB, III, Loop FD, et al. Guidelines for percutaneous transluminal coronary angioplasty. A report of the American College of Cardiology/American Heart Association Task Force on Assessment of Diagnostic and Therapeutic Cardiovascular Procedures (Subcommittee on Percutaneous Transluminal Coronary Angioplasty). Circulation 1988; 78:486-502.
(25.) Ishida J, Suzuki T, Aizawa K, Sawaki D, Nagai R. Comparison of analytical performance of two single-step measurement devices of B-type natriuretic peptide. Int Heart J 2012; 53:320-3.
(26.) Kono M, Yamauchi A, Tsuji T, Misaka A, Igano K, Ueki K, et al. An immunoradiometric assay for brain natriuretic peptide in human plasma. Jpn Soc Nuc Med Tech 1993; 13:2-7.
(27.) Suzuki T, Distante A, Zizza A, Trimarchi S, Villani M, Salerno Uriarte JA, et al. Diagnosis of acute aortic dissection by D-dimer: the International Registry of Acute Aortic Dissection Substudy on Biomarkers (IRAD-Bio) experience. Circulation 2009; 119:2702-7.
(28.) Ichiki T, Huntley BK, Heublein DM, Sandberg SM, McKie PM, Martin FL, et al. Corin is present in the normal human heart, kidney, and blood, with pro-B-type natriuretic peptide processing in the circulation. Clin Chem 2011; 57:40-7.
(29.) Peng J, Jiang J, Wang W, Qi X, Sun XL, Wu Q. Glycosylation and processing of pro-B-type natriuretic peptide in cardiomyocytes. Biochem Biophys Res Commun 2011; 411:593-8.
(30.) Kenny AJ, Bourne A, Ingram J. Hydrolysis of human and pig brain natriuretic peptides, urodilatin, C-type natriuretic peptide and some C-receptor ligands by endopeptidase-24.11. Biochem J 1993; 291:83-8.
(31.) Semenov AG, Seferian KR, Tamm NN, Artem'eva MM, Postnikov AB, Bereznikova AV, et al. Human pro-B-type natriuretic peptide is processed in the circulation in a rat model. Clin Chem 2011; 57: 883-90.
(32.) Suzuki T, Ishiwata S, Hasegawa K, Yamamoto K, Yamazaki T. Raised interleukin 6 concentrations as a predictor of postangioplasty restenosis. Heart 2000; 83:578.
(33.) Suzuki T, Kohno H, Hasegawa A, Toshima S, Amaki T, Kurabayashi M, et al. Diagnostic implications of circulating oxidized low density lipoprotein levels as a biochemical risk marker of coronary artery disease. Clin Biochem 2002; 35: 347-53.
(34.) Shigematsu S, Takahashi N, Hara M, Yoshimatsu H, Saikawa T. Increased incidence of coronary in-stent restenosis in type 2 diabetic patients is related to elevated serum malondialdehydemodified low-density lipoprotein. Circ J 2007; 71: 1697-702.
(35.) Cooke T, Sheahan R, Foley D, Reilly M, D'Arcy G, Jauch W, et al. Lipoprotein(a) in restenosis after percutaneous transluminal coronary angioplasty and coronary artery disease. Circulation 1994; 89: 1593-8.
(36.) Pearson TA, Mensah GA, Alexander RW, Anderson JL, Cannon RO III, Criqui M, et al. Markers of inflammation and cardiovascular disease: application to clinical and public health practice: a statement for healthcare professionals from the Centers for Disease Control and Prevention and the American Heart Association. Circulation 2003; 107:499-511.
(37.) Hahn JY, Kim HS, Koo BK, Na SH, Chung JW, Youn TJ, et al. One month follow-up C-reactive protein may be a useful predictor of angiographic restenosis and long-term clinical outcomes after bare metal stent implantation. Int J Cardiol 2006; 109:267-9.
(38.) Park DW, Lee CW, Yun SC, Kim YH, Hong MK, Kim JJ, et al. Prognostic impact of preprocedural C reactive protein levels on 6-month angiographic and 1-year clinical outcomes after drugeluting stent implantation. Heart 2007; 93:108792.
(39.) Moldoveanu E, Mut-Vitcu B, Tanaseanu GR, Marta DS, Manea G, Kosaka T, et al. Low basal levels of circulating adiponectin in patients undergoing coronary stenting predict in-stent restenosis, independently of basal levels of inflammatory markers: lipoprotein associated phospholipase A2, and myeloperoxidase. Clin Biochem 2008; 41:1429-33.
(40.) Farooq V, Gogas BD, Serruys PW. Restenosis: delineating the numerous causes of drug-eluting stent restenosis. Circ Cardiovasc Interv 2011; 4: 195-205.
Hirotaka Fujimoto, [1,2], ([dagger]) Toru Suzuki, [1,3], ([dagger]) * Kenichi Aizawa, , ([dagger]) Daigo Sawaki, [1,3] Junichi Ishida,  Jiro Ando,  Hideo Fujita,  Issei Komuro,  and Ryozo Nagai 
 Department of Cardiovascular Medicine and  Department of Ubiquitous Pre ventive Medicine, The University of Tokyo, Tokyo, Japan;  Life Science Research Center, Technology Research Laboratory, Shimadzu Corp., Kyoto, Japan.
([dagger]) H. Fujimoto, T. Suzuki, and K. Aizawa contributed equally to this work.
* Address correspondence to this author at: Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. Fax +81-3-5800-9847; e-mail: torusuzu-tky@ umin.ac.jp.
 Nonstandard abbreviations: PCI, percutaneous coronary intervention; BNP, B-type natriuretic peptide; A0, amyloid 0; DPP-IV, dipeptidyl-peptidase IV; CAG, coronary angiography; MS-IA, mass spectrometry-based immunoassay; IQR, interquartile range; CRP, C-reactive protein; OR, odds ratio.
Received January 16, 2013; accepted April 22, 2013.
Previously published online at DOI: 10.1373/clinchem.2013.203406
Table 1. Patient characteristics and demographics. (a) Factors associated with restenosis (cross-sectional study) Total No-stenosis n 105 83 Age, years 70 (63-76) 71 (63-77) Male sex 66 (63) 55 (66) Coexisting conditions Hypertension 90 (86) 73 (88) Diabetes mellitus 65 (62) 52 (63) Smoking 71 (68) 56 (67) Laboratory values Total BNP, pg/mL 51.9 (37.5-83.7) 54.0 (37.5-90.8) Creatinine, mg/dL 0.83 (0.70-0.94) 0.84(0.71-0.96) CRP, mg/L 0.5 (0.3-1.2) 0.5 (0.3-1.2) Ratio of total 3.1 (2.6-3.9) 3.1 (2.5-3.9) cholesterol to HDL cholesterol Total cholesterol, mg/dL 170.5 (152.5-190.5) 169.0 (153.9-189.3) HDL cholesterol, mg/dL 53.2 (44.5-68.6) 53.3 (44.5-68.9) Triglycerides, mg/dL 134.0 (85.5-184.8) 135.0(89.0-189.0) LDL cholesterol, mg/dL 88.5 (78.3-103.5) 87.0 (76.0-102.0) Systolic blood pressure, 128.0 (115.0-140.0) 128.0 (112.8-140.0) mmHg Diastolic blood 68.0 (60.0-78.5) 68.0 (60.0-78.0) pressure, mmHg BNP(5-32)/BNP(3-32) 1.35 (1.19-1.55) 1.43 (1.22-1.61) %DS by QCA (%) (c 14.43 (10.26-25.54) 12.68(9.18-17.14) Lesion length, mm 17.20 (12.58-22.45) 17.47 (13.42-21.89) Lipid-lowering agents 84 (77) 65 (78) Antihypertensive treatment 93 (90) 72 (88) Drug-eluting stent 79 (75) 69 (83) Factors associated with restenosis (cross-sectional study) Restenosis P (b) n 22 Age, years 69 (66-72) 0.41 Male sex 11 (50) 0.21 Coexisting conditions Hypertension 17(77) 0.30 Diabetes mellitus 13(59) 0.81 Smoking 15(68) 1.00 Laboratory values Total BNP, pg/mL 48.1 (31.1-71.3) 0.29 Creatinine, mg/dL 0.78 (0.65-0.89) 0.15 CRP, mg/L 0.6 (0.3-1.2) 0.50 Ratio of total 3.1 (2.8-3.8) 0.34 cholesterol to HDL cholesterol Total cholesterol, mg/dL 176.0(149.0-197.0) 0.82 HDL cholesterol, mg/dL 50.5 (41.5-65.0) 0.63 Triglycerides, mg/dL 117.0 (77.0-178.5) 0.39 LDL cholesterol, mg/dL 96.0 (84.0-107.5) 0.09 Systolic blood pressure, 128.0(116.0-142.0) 0.90 mmHg Diastolic blood 66.0 (58.0-80.0) 0.58 pressure, mmHg BNP(5-32)/BNP(3-32) 1.19(1.11-1.34) <0.001 %DS by QCA (%) (c 65.52 (59.22-70.54) <0.001 Lesion length, mm 14.02 (11.12-24.83) 0.28 Lipid-lowering agents 19(86) 0.55 Antihypertensive treatment 21 (100) 0.21 Drug-eluting stent 10(45) <0.001 (a) Data are median (IQR) or n (%). (b) P values were determined by the Fisher exact test for discrete variables and the Wilcoxon rank-sum test for continuous variables. c %DS, percent diameter stenosis; QCA, quantitative coronary angiography. Table 2. Univariate and multivariate analysis of factors associated with restenosis. Univariate analysis OR (95% CI) P Age 0.99 (0.94-1.05) 0.74 Male sex 0.51 (0.19-1.33) 0.17 Hypertension 0.47 (0.14-1.65) 0.22 Diabetes mellitus 0.86 (0.33-2.31) 0.76 Smoking 1.03 (0.39-2.98) 0.95 BNP 0.99 (0.98-1.00) 0.23 Creatinine 0.09 (0.004-1.28) 0.08 CRP 0.99 (0.86-1.08) 0.91 Ratio of total cholesterol 1.17 (0.69-1.93) 0.55 to HDL cholesterol Total cholesterol 1.00 (0.98-1.01) 0.53 HDL cholesterol 0.99 (0.96-1.02) 0.70 Triglycerides 1.00 (0.99-1.00) 0.26 LDL cholesterol 1.01 (0.99-1.03) 0.44 Systolic blood pressure 1.00 (0.97-1.03) 0.90 Diastolic blood pressure 0.99 (0.95-1.03) 0.65 BNP(5-32)/BNP(3-32) 0.60 (0.43-0.78) <0.001 Lesion length 0.97 (0.91-1.03) 0.39 Lipid-lowering agents 1.75 (0.52-8.05) 0.38 Antihypertensive treatment 3.21 (0.57-60.32) 0.21 Drug-eluting stent not used 5.91 (2.16-16.80) <0.001 Multivariate analysis (a) OR (95% CI) P Age Male sex Hypertension Diabetes mellitus Smoking BNP Creatinine CRP Ratio of total cholesterol to HDL cholesterol Total cholesterol HDL cholesterol Triglycerides LDL cholesterol Systolic blood pressure Diastolic blood pressure BNP(5-32)/BNP(3-32) 0.63 (0.45-0.83) <0.001 Lesion length Lipid-lowering agents Antihypertensive treatment Drug-eluting stent not used 4.20(1.40-12.99) 0.011 (a) Only variables from the univariate analysis that had a P value of <0.2 were retained in the multivariate model. The final model included only variables that had a P value of <0.05.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||Proteomics and Protein Markers|
|Author:||Fujimoto, Hirotaka; Suzuki, Toru; Aizawa, Kenichi; Sawaki, Daigo; Ishida, Junichi; Ando, Jiro; Fujit|
|Date:||Sep 1, 2013|
|Previous Article:||The importance of commutability of reference materials used as calibrators: the example of ceruloplasmin.|
|Next Article:||Fasting serum lipid and dehydroepiandrosterone sulfate as important metabolites for detecting isolated postchallenge diabetes: serum metabolomics via...|