CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 6, July 2012
330
AFRICA
Assessment of serum leptin, pregnancy-associated
plasma protein A and CRP levels as indicators of plaque
vulnerability in patients with acute coronary syndrome
MOUSHUMI LODH, BINITA GOSWAMI, ASHOK PARIDA, SURAJEET PATRA, ALPANA SAXENA
Abstract
Introduction:
A multifactorial aetiology of coronary artery
disease (CAD) has been established in the recent past.
Extensive research is now underway to understand the
mechanisms responsible for plaque vulnerability. The identi-
fication of a novel biomarker that will help in the assessment
of plaque status is urgently needed for the purpose of patient
stratification and prognostication. The aim of the present
study was to evaluate leptin, pregnancy-associated plasma
protein A (PAPP-A) and C-reactive protein (CRP) levels in
patients with acute coronary syndrome and to assess their
diagnostic efficacy in the identification of vulnerable plaques.
Methods:
The study group comprised 105 patients who had
chest pain along with ECG changes (ST elevation, ST depres-
sion, T inversion) and raised cardiac enzyme levels. Sixty-two
patients with chest pain and ECG changes but with normal
cardiac enzyme profiles were included in the control group.
Lipid profiles, and leptin, PAPP-A and CRP levels were
assessed in these two groups. Receiver operating characteris-
tics (ROC) curves were plotted to determine the utility of the
parameters under study as markers of plaque vulnerability.
Results:
Significantly higher levels of serum lipoprotein (a),
leptin, PAPP-A and high-sensitivity CRP (hs-CRP) were
observed in the cases than in the controls. A positive correla-
tion was observed between CRP and PAPP-A levels as well as
CRP and leptin concentrations. ROC curve analysis revealed
similar efficacies of CRP and PAPP-A levels in their ability to
detect unstable plaques with areas under the curve of 0.762
and 0.732, respectively. Multivariate analysis established the
superiority of hs-CRP as a predictor of plaque instability.
Conclusions:
Our study highlights the utility of both CRP
and PAPP-A levels as determinants of plaque instability. Our
findings necessitate population-based follow-up studies to
establish the superiority of either of the two biomarkers in
the field of preventive cardiology.
Keywords:
leptin, hs-CRP, PAPP-A, metalloproteinase, plaque
rupture
Submitted 7/2/11, accepted 8/2/12
Cardiovasc J Afr
2012;
23
: 330–335
DOI: 10.5830/CVJA-2012-008
Acute coronary syndrome (ACS) accounts for 20% of all
medical emergency admissions and has the highest risk for
adverse effects and deaths.
1
ACS encompasses patients who
present with unstable ischaemic heart disease (ST elevation
myocardial infarction, non-ST-elevation myocardial infarction).
The rupture of coronary atherosclerotic plaque and subsequent
thrombus formation are major events underlying ACS.
Apart
from traditional risk factors, several novel risk factors have been
found to be associated with acute coronary syndromes.
2
Atherosclerosis results due to the complex interplay between
environmental, genetic and individual risk factors. Physical
inactivity, along with the intake of calorie-dense food account
for the energy imbalance that is widely prevalent in developing
and developed countries. The metabolic perturbations due to
this energy imbalance along with smouldering inflammatory
processes and other as yet poorly understood mechanisms
initiate and aggravate the atherosclerotic process.
3,4
The scientific community is engrossed in extensive research
in order to discover biomarkers that will help stratify patients
who are more prone to develop the complications consequent
to atherosclerosis. The inability of lipid levels to provide an
insight into the ongoing atherosclerotic process and impending
complications has further necessitated the identification of
novel markers that assess the dynamics of atherosclerosis.
Adipocytokines (leptin), pregnancy-associated plasma protein A
(PAPP-A) and high-sensitivity C-reactive protein (hs-CRP) are
the newer emerging biomarkers for assessing plaque stability.
5
Adipose tissue is now identified as an active endocrine
organ and not merely a storage site for fat. The mediators
released by adipose tissue are known as adipocytokines or
adipokines.
6
Leptin is one such adipokine implicated in a
number of physiological processes.
7
Other important adipokines
are adiponectin and resistin. It has been demonstrated that
alterations in the plasma levels of these adipokines as well as
disturbances in the signalling pathways disrupt the delicate
adipokine biology and subsequently give rise to many disorders.
6
Recent studies have indicated that hyperleptinaemia may serve as
a cardiovascular risk factor.
8-10
PAPP-A is a glycoprotein produced by the placental synctio-
trophoblastic cells and was initially discovered in the sera
Department of Biochemistry, The Mission Hospital,
Durgapur, West Bengal, India
MOUSHUMI LODH, MD
Department of Biochemistry, GB Pant Hospital, New Delhi,
India
BINITA GOSWAMI, MBBS, MD, DNB,
Department of Cardiology, The Mission Hospital, Durgapur,
West Bengal, India
ASHOK PARIDA, MD
Department of Biochemistry, Lady Hardinge Medical College
and associated hospitals, New Delhi, India
SURAJEET PATRA, MD
Department of Biochemistry, Maulana Azad Medical College
and associated hospitals, New Delhi, India
ALPANA SAXENA, MD
