1. Soluble Lectin-Like Oxidized LDL Receptor-1
and High-Sensitivity Troponin T as Diagnostic
Biomarkers for Acute Coronary Syndrome
Prepared by
Nagi Abdalla
Supervisors
Prof. Kim Dong Hyun Prof. Jea Gook Shin

2. Project objectives (what, why and how)
• About Cardiovascular disease and Acute
Coronary Syndromes..
• Importance and clinical impact..
• The road to biomarker discovery..

3. Acute Coronary Syndromes
• Definition..
• The triad:
– STEMI
– NSTEMI
– Unstable angina
• Prognosis in Acute coronary syndromes..

4. Method overview
• Biomarker type approach:
– Screening:
• study of risk factors
– Diagnostic:
• Mechanism of vascular endothelial dysfunction and
injury
• Mechanism of ischemia in cardiac cells
– Prognostic:
• Cell injury (reversible/irreversible)
• Long term observation and prolonged
exposure to ischemia
• Methodological approach:
– Analysis: (global and target based approach)
• Use of proteomics
• Use of metabolomics
– Clinical:
• Study of patients at risk
• Study of patients during the event
• Study of patients after injury

6. Soluble LOX-1 Plus hs-TnT for ACS
INTRODUCTION

7. Introduction
• Problems with current cardiac
biomarkers
– CK-MB
– Cardiac Troponins and high
sensitivity Troponins
• Other conditions mimicking
ACS:
– coronary spastic angina pectoris
(CSA),
– pulmonary thromboembolism,
– perimyocarditis
– (pericarditis and/or myocarditis)
– takotsubo cardiomyopathy.

8. About Lectin-like oxidized LDL receptor-1
(LOX-1)
• LOX-1 receptor is present in:
– Surface of intimal smooth muscle cells (VSMC)
– Lipid-laden macrophages (in advanced human atherosclerotic
plaques)
• The expression of this receptor is induced by factors
related to atherogenesis and plaque vulnerability
such as:
– Proinflammatory cytokines
– Angiotensin II
– Hyperglycemia
– Oxidized LDL
• In the vulnerable plaque stage; sLOX-1 is released
into the circulation after being cleaved by protease
enzymes (disintegrin/metalloproteinase)
• These evidence points out that sLOX-1 is a
biomarker for plaque rupture or plaque instability

9. About Lectin-like oxidized LDL receptor-1 (LOX-1) (cont.)
• a receptor for atherogenic oxidized LDL
• abundantly expressed in advanced human atherosclerotic
plaques
• soluble LOX-1 (sLOX-1) is regarded as a marker of plaque
rupture or instability..
• previous studies revealed the diagnostic value of sLOX-1 for
early-stage ACS in which conventional troponin T (TnT) was
unable to provide a diagnosis

10. Aim of this study
• evaluate the diagnostic value of sLOX-1
and hs-TnT for patients in the ER with
chest symptoms & ECG abnormalities
suggestive of ACS.

11. Soluble LOX-1 Plus hs-TnT for ACS
METHODS

12. Study Population
• Time line  April2008/Dec.2009
• Number of patients: 200 (160 males-40 females)
• Mean age: 65±12 years
• Presentation: ER within 48hrs with chest symptoms and
ECG abnormalities suggestive of ACS (diagnosis within
first 3 hours of onset of symptoms were defined as early)
• ACS parameters:
– prolonged chest pain >20mins
– Coronary lesion seen on coronary angiography
– Diagnosis of NSTEACS and STEACS was according to ECG findings
• Exclusions:
– Patients with acute/chronic renal disease under going renal replacement
therapy.
– Patients with cardiogenic shock on percutaneous cardio-pulmonary support
system.

13. Measurement of sLOX-1 & hs-TnT
sampling methods and biomarker measurement
• Collection and treatment of samples:
– Blood samples obtained in ER.
– Plasma separated by centrifugation.
– Stored in -80ºC.
• Measurement tools:
• For plasma sLOX-1:
– measured by Chemiluminescent enzyme immunoassay (CLEIA)
using anti-human LOX-1 monoclonal antibodies (modified ELISA).
– Intra-and inter-assay coefficients of variation (CV) where 4.4-6.5%
and 4.0-6.1% respectively
– Lower limit of detection was 8.0pg/ml
• For serum hs-TnT:
– Measured by Electrochemoluminescence immunoassay
– Intra- and inter-assay CV were 0.5-5.7% and 1.4-3.0% respectively
– Lower limit of detection was 0.003ng/ml

14. Statistical Analysis
• Variable groups of data obtained for sLOX-1, hs-
TnT, CK-MB at different time intervals
• Analytical tools used for comparison are:
– Student’s T-test  for 2 groups comparison
– 1-way ANOVA  for 3groups comparison
– Mann Whitney U test  2 groups with unequal distribution of time
intervals
– Kruskal-Wallis test  3 groups with unequal distribution of time
intervals
– Spearman’s rank correlation test  comparing both sensitivity and
specificity of sLOX-1 & hs-TnT for diagnosing ACS
– Receiver-operating characteristics (ROC curve) using non-ACS
subjects as negative controls..
• Software used: SPSS software package
• Ethically approved and consents collected

15. Soluble LOX-1 Plus hs-TnT for ACS
RESULTS

16. Characteristics of the Enrolled
Patients
• 200 consecutive patients as follows:
– 160 with ACS
– 116 STEACS
– 44 NSTEACS
– 40 with non-ACS
– 23 CSA
– 6 arrhythmia
– 6 pulmonary thromboembolism
– 3 perimyocarditits
– 2 takotsubo cardiomyopathy

18. I. Comparison of sLOX-1 & hs-TnT
levels

19. Comparison of sLOX-1 & hs-TnT levels (cont.)

20. Comparison of sLOX-1 & hs-TnT levels (cont.)
sLOX-1 hs-TnT

21. II. Diagnostic overall Value of
sLOX-1 & hsTnT for ACS

22. III.Comparing the diagnostic value of sLOX-
1 & hs-TnT for early stage of ACS
(within 3h of the onset of symptoms)

23. IV. Evaluating the Diagnostic Value of sLOX-1 for
ACS in patients with hs-TnT negative ACS
• 2 subgroups:
I. hs-TnT negative ACS (<0.0205ng/ml)
II. hs-TnT postive ACS (>0.0205ng/ml)
• Findings:
– Gender and the prevalence of risk factors were comparable in the 2 groups except that
patients were younger in the 1st subgroup
– Plasma sLOX-1 levels were significantly higher in the 1st subgroup
– Peak CK-MB levels were also comparable between these subgroups & Serum creatinine
levels were significantly higher in the 1st subgroup
– Time intervals from the onset of chest symptoms to ER arrival were significantly shorter
in the 1st subgroup

24. Evaluating the Diagnostic Value of sLOX-1 for ACS in patients with hs-TnT negative ACS (cont.)
Negative reference:
hs-TnT-negative non-ACS subgroup

25. V. Evaluating the Diagnostic Value of hs-TnT for
ACS in Patients with sLOX-1 negative ACS
• 2 subgroups:
I. sLOX-1 negative ACS (<131.7pg/ml)
II. sLOX-1 positive ACS (>131.7pg/ml)
• Findings:
– Gender and the prevalence of risk factors were comparable in the 2 groups except
that smokers were more prevalent in the 2nd subgroup.
– patients with STEACS were more prevalent in the 2nd subgroup.
– Serum hs-TnT and creatinine levels were comparable between these subgroups &
Peak serum CK-MB levels were higher in the 2nd subgroup
– Time intervals from the onset of chest symptoms to ER arrival were significantly
shorter in the 2nd group.

26. Evaluating the Diagnostic Value of hs-TnT for ACS in Patients with sLOX-1 negative ACS (cont.)
Negative reference:
sLOX-1-negative non-ACS subgroup

29. Soluble LOX-1 Plus hs-TnT for ACS
DISCUSSION

30. • About AMI..
• Troponin as a specific cardiac biomarker..
• Recent studies revealed insufficiency of tropnin as a biomarker in early
stage ACS (within 3 h of onset)  the cause is mainly related to the kinetics
of cardiac troponins during the acute stage of ACS
• sLOX-1 is regarded as a biomarker for plaque rupture or plaque instability
and expected to precede the release of myocardial damage markers,
including cardiac troponins  superior in diagnosis in early stage
• The development of high sensitivity assay for early detection of Troponins
was associated with decreased specificity  other non-ACS conditions
shared the same clinical presentation and elevated troponins with or without
cardiac ischemia

31. • Other markers of cardiac damage include:
– Myoglobin
– Heart-type fatty acid-binding protein (H-FABP)
These markers are also present in early stage AMI but their diagnostic
specificity is of the same as troponins since they share the same mechanism.
• Therefore, sLOX-1 may be a better candidate since it has a different
mechanism involving plaque instability and rupture
• By using non-ACS patients as negative reference; this study showed for the
first time the ability of sLOX-1 to detect ACS during the acute stage in cases
with no increased hs-TnT levels
• Although the combination of sLOX-1 & hs-TnT are useful in diagnosis of
ACS; their diagnostic specificity remains insufficient  both markers were
found elevated in non-ACS conditions:
– Some types of coronary vasospasm
– Thrombus formation in the pulmonary artery
– Synovial fluid  rheumatoid arthritis (Arthritis & Rheumatism art.33452)

32. • sLOX-1 levels were found higher in STEACS than NSTEACS
– Short arrival interval in STEACS
– Different plaque characteristics (rupure/erosion)
• Peak CK-MB values were higher in patients with sLOX-1>131.7pg/ml 
indication of severity
• sLOX-1 can be an alternative to detect vulnerable plaques (less invasive)
 current methods are considered invasive:
– Multidetector row CT
– IV U/S
• sLOX-1 is found reduced in patients on statins, Angiotensin II receptor
blockers, body weight reduction
 it can be used as a tool to monitor therapeutic effects

33. Soluble LOX-1 Plus hs-TnT for ACS
CONCLUSION

34. • sLOX-1  is a biomarker of plaque rupture or vulnerability
• hs-TnT  is a biomarker of myocardial damage
using either one of them alone appears to be insufficient for diagnosing ACS
in the real clinical setting
therfore, the diagnostic accuracy would improve by using the combination of
both..
• sLOX-1 has its limitations: since it is also elevated in other atherosclerotic
conditions like:
– Ischemic stroke
– Aortic athersclerosis
– Peripheral arteriosclerosis obliterance
• Further studies are need to clarify the mechanisms of sLOX-1 elevation

35. 정말 감사합니다!