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From a strictly clinical point of view, the information provided by ANP and BNP and their related peptides,
MR-proANP or NT-proBNP, is not substantially different.
From an analytical point of view, however, it is essential to
note that active hormones (ANP and BNP) are less stable
invitro than their respective nonactive peptides, such as prohormones (proANP and proBNP) or N-terminal peptides
(such as NT-proANP, MR-proANP, and NT-proBNP). Active
hormones should only be measured in plasma-EDTA samples (which partially inhibits enzymes that degrade hormones in plasma), whereas NT-proANP, MR-proANP, and
NT-proBNP peptides can be assayed in either plasma-EDTA
or lithium-heparin plasma or serum.
Although BNP and NT-proBNP values are closely correlated in most clinical conditions, recent studies in patients
with chronic heart failure treated with a new drug called
LCZ696 (Entresto) have shown conicting results. This
pharmacological combination consists of two substances: a
specic competitor of the angiotensin II receptor (valsartan)
and an inhibitor of the enzyme neprilysin (sacubitril). A
recent multicenter study, called PARADIGM-HF, showed
that plasma BNP levels were higher in patients treated with
LCZ696 than in those treated with enalapril. In contrast, circulating levels of NT-proBNP were lower during treatment
with LCZ696 than with enalapril. Thus, for the rst time,
anopposed behavior between the levels of active BNP hormone and inactive NT-proBNP peptide in patients undergoing pharmacological treatment for heart failure has
beendescribed in the literature. These data, therefore, require
an ad hoc physiopathological interpretation that takes into
account the dual action of the drug: inhibition of theperipheral degradation of BNP (with a consequent increase in the
circulating levels of the active hormone) and of the renin–
angiotensin system with a decreased production of cardiac
natriuretic peptides by the myocardial cells (Fig. 22.5).
Consequently, the clinician’s interpretation of natriuretic
peptide changes during treatment with this pharmaceutical
combination requires special attention. In particular, all cases
of increased plasma levels of BNP not linked to the inhibition effects of the drug on the degradation of the hormone but
secondary to a worsening of the patient’s clinical conditions
must be recognized.
Biomarkers ofMyocardial Remodeling
andFibrosis
Cardiac remodeling is generally considered the most important pathophysiological mechanism determining the progressive development of heart failure in patients with extensive
ventricular myocardial infarction or long-standing myocardial disease. In the year 2000, a consensus conference
dened cardiac remodeling as the result of changes in the
Inactive
Bradykinin
ACE NEP
RENIN
Fig. 22.5 Interrelationship between the renin-angiotensin system and
the B-type natriuretic peptide system with plasma proteolytic enzymes
ACE (angiotensin I converting enzyme) and NEP (neprilysin). The
NEP enzyme degrades natriuretic peptides (including BNP), bradykinin, and angiotensins, transforming them into shorter and inactive peptides. The ACE enzyme acts on bradykinin, inactivating it, and on
angiotensin I (angio I), transforming it into the much more active peptide angiotensin II (angio II). The inhibition of the NEP enzyme, therefore, causes high levels of bradykinin, angiotensin II, and natriuretic
peptides (ANP, BNP, and CNP), which have contrasting effects on the
cardiovascular system. (Copyright EDISES 2021. Reproduced with
permission)
Angio I
degradation
Angio II
products
Inactive
degradation
products
BNP
Inactive
degradation
products
expression of the cellular genome of myocardial tissue that
induces changes, at the molecular level, of cellular structure
and interstitial matrix that produce changes in the weight,
shape, and function of the heart. These anatomopathological
alterations are caused by hemodynamic overload and/or cardiac damage, and the subsequent progressive cardiac remodeling is inuenced by hemodynamic alterations and activation
of the neuro-immune-hormonal system. Heart failure is the
nal common pathway of all cardiovascular diseases (of
which coronary ischemia covers more than half of the cases
in Western countries), so patients with a wide variety of clinical conditions can be affected. For this reason, they show a
different propensity to develop ventricular remodeling and
brosis.
Patients with HFare distinguished into two groups concerning the value of left ventricular systolic ejection fraction
(LVEF), usually assessed by echocardiographic examination, which can be reduced (≤40%, Heart Failure with
Reduced Ejection Fraction [HFrEF]) or preserved (≥50%,
Heart Failure with Preserved Ejection Fraction [HFpEF])
(Table22.3). The epidemiology, etiology, pathophysiologic
mechanisms, anatomopathological picture, and clinical disease progression that characterize these two groups of
patients are substantially different. Patients with HFpEF are
generally older, female, andhave comorbidities (hypertension, obesity, diabetes mellitus, atherosclerosis, atrial brillation, and renal failure) and diastolic dysfunction on
echocardiographic examination. The number of patients with
HFpEF has increased in recent years, reaching that of
patients with HFrEF, whose incidence has decreased. Thus,
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Table 22.3 Denition of heart failure with preserved (HFpEF), midrange (HFmrEF), and reduced (HFrEF) ventricular ejection fraction
according to ESC guidelines 2016
Criteria HFrEV HFmrEV HFpEF
1 Signs and
symptoms
2 LVEF
<40%
3 _ High concentrations
LAE left atrium enlargement, LVH left ventricular hypertrophy, LVEF
left ventricular ejection fraction
Signs and symptoms Signs and symptoms
LVEF 40–49%
of natriuretic peptides
At least one of the
following criteria:
-Signicant
structural
alterations (LVH
and/or LAE)
-Diastolic
dysfunction
LVEF ≥50%
High concentrations
of natriuretic peptides
At least one of the
following criteria:
-Signicant
structural
alterations (LVH
and/or LAE).
-Diastolic
dysfunction
the prevalence of the two different clinical conditions in the
general population is estimated to be similar. Diagnosis and
treatment are more complex in patients with HFpEF, for
which the prognosis is more severe. In accordance with the
2016 ESC guidelines, the diagnosis of HFrEF is based only
on the presence of clinical symptoms and the assessment of
<40% LVEFreduction, whereas the diagnosis of heart failure with preserved or intermediate LVEF (LVEF between 40
and 50%) requires elevated natriuretic peptide values and
structural or functional alterations in the ventricle, indicating
the presence of diastolic dysfunction (Table22.3).
Cardiac brosis, whose most evident aspect is ventricular
wall thickening, occurs more frequently in patients with
HFpEF than in those with HFrEF, representing the most
important pathogenetic mechanism of diastolic dysfunction.
This evidence has stimulated in recent years the research and
clinical validation of reliable biomarkers of cardiac brosis
for the diagnosis, risk stratication, and monitoring of
patients with HFpEF. Considering the results obtained in
these studies, the 2013 American College of Cardiology
Foundation and American Heart Association guidelines
included, for the rst time, biomarkers of cardiac brosis,
and in particular galectin-3 and the soluble IL-33 receptor,
called sST2, among the biomarkers for risk stratication in
patients with heart failure.
From a physiopathological point of view, these biomarkers have the critical limitation to not be cardio-specic since
they can be produced by numerous immunocompetent cells,
mature or immature broblasts, or even endothelial or epithelial cells, especially during local or even systemic inammatory processes.
Thus, for the clinician, it is often impossible to link variations in the circulating levels of these biomarkers to possible
pathophysiological processes specically located in the
myocardium (and not in other organs, such as kidney, liver,
and lungs).
Cardiac Fibrosis
Fibroblasts account for about two-thirds of the myocardial
cell population, whereas myocardiocytes account for about
two-thirds of the myocardial mass. Myocardial remodeling
in ischemic and nonischemic myocardial disease involves
myocardiocytes, other myocardial tissue cells (especially
broblasts and endothelial cells), and the extracellular
matrix.
Specically, collagen is secreted by broblasts as procollagen into the extracellular matrix, where proteases remove
the carboxy-terminal amino acid propeptide, which will subsequently be degraded by matrix metalloproteases (MMPs),
which in turn are regulated by the tissue inhibitor of metalloproteases (TIMP). Under pathological conditions, the cardiac interstitium may increase due to diffuse deposition of
collagen bers, edema (e.g., secondary to an inammatory
process), or pathological deposition of proteins that physiologically are not present in the cardiac extracellular matrix
(such as amyloid). Recent studies have shown that activation
of the renin–angiotensin–aldosterone system within cardiac
tissue plays a central role in broblast activation and collagen deposition.
Cardiac brosis is generally dened as the proliferation of
broblasts with increased deposition of cardiac muscle collagen bers or (more rarely) brotic thickening of the heart
valves. Fibrosis makes the heart muscle stiffer and less elastic, reducing the ability of the ventricles to dilate (ventricular
diastolic dysfunction). In addition, brosis can affect the
heart valves leading to valve dysfunction (stenosis and/or
insufciency).
Myocardial brosis can originate through two distinct
pathophysiologic processes that result in two different
phenotypes:
- Fibrosis can result from the loss of myocardial tissue
(e.g., due to an extensive myocardial infarction), which must
be considered as an actual scar (reparative or replacement
brosis);
- In non-ischemic myocardiopathies, generally on a
chronic inammatory basis, an increase in the interstitial
matrix is produced, which is generalized to the whole ventricle (or to a large part of it). This type of brosis is, therefore, called interstitial and is of reactive type and originates
in the areas surrounding the blood capillaries from where it
then radiates to the entire myocardial tissue.
The death of myocardiocytes and their replacement with
brotic tissue cause important alterations in cardiac function.
Both increased extracellular synthesis and decreased extracellular matrix can cause increased ventricular wall stiffness,
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the most important cause of ventricular diastolic dysfunction. In addition, extracellular matrix deposition between
myocardiocytes can alter the propagation of electrical
impulses through the myocardium, causing both
abnormalities of contraction and cardiac arrhythmias, which
can also be fatal. Finally, inammatory edema and brotic
tissue deposition around the perivascular areas, by slowing
the ow of oxygen and nutrients to the myocardiocytes, trigger the vicious cycle that supports the progression of myocardial remodeling.
Biomarkers ofCollagen Synthesis
andDegradation
Extracellular matrix remodeling in the heart is an active and
highly complex process orchestrated by matrix-degrading
MMPs and their TIMP inhibitors. MMPs constitute a complex family of enzymes of the protease group, of which at
least 28 members have been identied (indicated by progressive numbers from MMP-1 to MMP28), classied according
to the nature of the most important functional groups in their
catalytic site, which requires the presence of metal ions as
cofactors (zinc or cobalt). Four members of the MMP inhibitor family (TIMP-1 to TIMP-4) were identied.
The brillar collagen in the heart is predominantly of type
I (85%) and type III (11%); the latter provides elasticity to
the myocardium, while the former contributes most to the
strength and resistance of the myocardium to wall stress and
deformation. Collagen undergoes turnover by the action of
broblasts and myobroblasts, which respond to mechanical
stress and autocrine and paracrine factors (such as angiotensin II, aldosterone, cytokines, and growth factors), partly
secreted by monocytes and macrophages. An increase in collagen deposition results from the increased proliferation of
broblasts/myobroblasts and their collagen synthesis and
secretion rate. Fibrillar collagen is synthesized as preprocollagen in the endoplasmic reticulum of broblasts and
transformed into procollagen with a triple helix structure.
Procollagen, secreted into the extracellular matrix, is then
cut by proteases to form type I and III collagen brils that
contribute to the extracellular matrix’s structure and the
myocardium’s mechanical characteristics.
Although cardiac tissue biopsy is considered the gold
standard for diagnosis, some markers of collagen turnover
have been proposed for the noninvasive estimation of myocardial brosis. Although numerous markers of collagen
turnover have been identied and described, the most robust
evidence involves PICP (Procollagen type I C-terminal
Propeptide), PIIINP (Procollagen type III N-terminal
Propeptide), and ICTP (type I Collagen TeloPeptide).
Many studies, especially case-control, measured circulating biomarkers of extracellular matrix turnover in patients
with heart failure. However, analytical difculties limited
their use in clinical practice. Additionally, the results of these
studies are difcult to compare with each other because they
differ in the number and type of biomarkers analyzed, the
study design(case–control vs. cohort, prospective or retrospective study), and the number and demographic (especially
age and sex) and clinical characteristics of the
enrolled patients. Also, the methods used to measure the
same biomarker in the different studies present very different
analytical characteristics; generally, RIA or ELISA methods
were used. In many studies, the main analytical characteristics and performance (sensitivity, reproducibility, and specicity of the antibodies used) of the methods used are not
even specied, so it is impossible to compare the data
obtained in different studies, even considering the same biomarker. Some authors have suggested that the PICP/ICPT
ratio could better estimate type I collagen turnover than a
single marker. However, it should be noted that the absolute
differences between healthy subjects and patients with heart
failure are generally much smaller than those observed in
natriuretic peptides, which show differences of the order of
10-fold or more between the median value of a population of
patients with heart failure compared to that observed in
healthy subjects. This reduced differential between cases and
controls reduces the diagnostic and prognostic accuracy of
the biomarker, especially in identifying patients with early
forms of the disease. This explains why these biomarkers
have a much lower diagnostic and prognostic power than
BNP and NT-proBNP. In conclusion, although there are
many studies on the circulating levels of collagen and extracellular matrix turnover biomarkers, there is currently insufcient evidence to support their use in clinical practice for
the diagnosis, prognosis, or treatment of patients with heart
failure.
Biomarkers ofMyocardial Fibrosis
Biomarkers of cardiac brosis, especially galectin-3 and the
soluble cytokine receptor protein IL-33 (commonly referred
to as sST2), have been increasingly studied since 2005.
Considerable evidence, even if not denitive, has therefore
been produced on their possible use as biomarkers of prognosis in patients with heart failure. Thus, the 2013 guidelines
of the American College of Cardiology Foundation and
American Heart Association scientic societies suggest their
use for prognostic assessment in patients with acute HF.
Galectin-3
Galectin-3 is a lectin that binds compounds containing a
β-galactosidic bond, characteristic of many glycans on the
cell surface. Many experimental studies show that galectin-3
is involved in many functions at the cellular level, such as
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adhesion, activation, chemotactic attraction, growth, differentiation, and apoptosis. An increase in galectin-3 expression induces broblast proliferation and collagen production,
thus contributing to the increase in cardiac brosis and subsequent remodeling.
Especially after the rst decade of this century, numerous
clinical studies on this biomarker have been published,
favored by the commercialization of immunometric methods
applied to automated platforms with excellent analytical performance. Galectin-3 was initially studied as a mediator of
growth and progression of several types of tumors, and only
later, its strong association with clinical conditions characterized by chronic inammation and interstitial brosis
wasnoted. Galectin-3 is present in the cytoplasm of different
cell types and is particularly abundant in macrophages.
The rationale for the candidacy of galectin-3 as a marker
in heart failure comes from studies in animal models published in the early years of the new century, which have
shown that this leptin can regulate the hypertrophic response
and functional cardiac damage following the administration
of angiotensin II or constriction of the aorta. The results of
these experimental studies paved the way for clinical trials
that sought to evaluate whether galectin-3 could play a role
as a marker of brosis, inammation, and cardiac remodeling in patients with heart failure. Furthermore, in November
2010, the Food and Drug Administration (FDA) approved
the determination of galectin-3in conjunction with clinical
evaluation to dene the prognosis of patients with chronic
heart failure. Subsequently, many studies have been published to assess the prognostic relevance of galectin-3 in
patients with heart failure, especially HFpEF type.
Unfortunately, these studies are primarily case–control. In
2015, a meta-analysis, considering 9 cohort studies,
showeda signicant association between mortality and biomarker levels; however, this study has, as an important limitation related to the signicant heterogeneity of the data
used for the meta- analysis. In addition, data derived from
cohort studies are generally the result of post hoc analysis
and, therefore, require conrmation with specic clinical
protocols.
As previously pointed out for markers of inammation
and turnover of collagen and extracellular matrix, also for
galectin-3 a modest difference is observed between the concentrations ofhealthy subjects and heart failure patients (on
average from 15% to 40%). For this reason, in many statistical evaluations, the measurement of galectin-3 does not add
signicant prognostic information to other prognostic markers (especially that of natriuretic peptides).
It should be noted, however, that the biological variability
of galectin-3 both intraindividually (about 5–8% in healthy
subjects, as well as in patients with chronic stable heart failure) and interindividually (about 27% in healthy subjects and
40% in patients with chronic stable heart failure) is much
lower than that of natriuretic peptides or troponins. The relatively low biological variability coupled with the excellent
analytical performance of the currently available automated
assay methods makes the biochemical information provided
by galectin-3 very robust in monitoring individual subjects/
patients.
Compared with the sST2 protein, galectin-3 possesses the
advantage of being more closely related to chronic inammatory processes resulting in interstitial brosis in patients
with heart failure. If this hypothesis is conrmed, galectin-3
could be considered a biomarker of cardiac remodeling associated with myocardial interstitial brosis.Thus, Galectin-3
could be used to screen patients with HFpEF who are still
asymptomatic or pauci-asymptomatic, to identify those who
will need to undergo more expensive (such as gadoliniumenhanced MRI) or invasive (such as biopsy or arteriography)
tests to conrm cardiac brosis, and then be targeted to specic and more aggressive therapies.
Soluble IL-33 Receptor (sST2)
The ST2 protein belongs to the interleukin-1 receptor family
(IL-1 RL-1) and exists in two isoforms, transmembrane
(ST2L) and soluble (sST2). The specic ligand of the STL2
receptor is IL-33, which plays an anti-inammatory, antihypertrophic, and antibrotic role in the myocardium. The soluble ST2 receptor is the ST2L receptor, which, through
specic proteases, undergoes a cut at the transmembrane and
cytoplasmic domains with subsequent release into the extracellular uid. In the extracellular uid and plasma, the sST2
protein can still bind its specic IL-33 high-afnity ligand,
sequestering it and making it no longer available for binding
to its membrane receptor. In this way, the sST2 receptor
blocks the favorable effect of IL-33 on the myocardium by
behaving as a decoy receptor.
High circulating levels of sST2promote proinammatory
mechanisms leading to myocardial remodeling, cardiac
brosis, and ventricular diastolic dysfunction. In accordance
with this mechanism of action, many studies have shown that
patients with heart failure have high circulating levels of
sST2. However, as also pointed out for galectin-3, the measurement of sST2 does not always add signicant prognostic
information compared with other biomarkers, especiallynatriuretic peptides. Currently, it is impossible to measure sST2 by the most common automated platforms
available in clinical laboratories, so its clinical use is limited
to specialized centers, and, consequently, the results available in the literature are fewer than those related to galectin-
3. sST2, however, provides better results than galectin-3in
evaluating patients with HFrEF than those with HFpEF. In
addition, some authors have reported that sST2 can stratify
the risk of progression of cardiac remodeling in patients with
reduced left ventricular function (with or without symptoms
of heart failure).
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In conclusion, further prospective clinical cohort studies, with a sufcient number of heart failurepatients, both
with HFpEF and HFrEF, monitored for a signicant number
of years, are needed to evaluate and compare the possible
prognostic relevance of galectin-3 and sST2 among themselves and concerning other biomarkers whose prognostic
role is widely recognized, in particular natriuretic peptides
and troponins, measured by methods with high analytical
sensitivity.
Genetic Biomarkers Associated
withCardiovascular Diseases
The genomicanalysis includes many procedures, very different from each other, which allow the identication of possible genes (candidate genes), whose altered function could be
responsible for particular and rare forms of cardiovascular
diseases (monogenic diseases). Additionally, some polymorphisms (gene variants) could be associated with an increased
risk of cardiovascular events.
Malformations of the heart and great vessels account for
a large proportion of congenital disabilities in about 1% of
live births. Some of these forms may be caused by chromosomal alterations (such as deletion or translocation) or by
mutations in a single gene. In addition, some of the idiopathic forms of dilated or hypertrophic myocardiopathy,
especially familial forms, may be caused by the altered
function of a single gene and be heritable. Finally, some
familial forms of cardiac arrhythmias may also recognize a
genetic basis because they are caused by an alteration in the
function of a single or a few genes. In all these cases, the
genetic test, if available, can not only conrm the diagnosis
but also offer the opportunity for appropriate counseling in
highly specialized departments and/or suggest new treatment protocols.
However, considering the cardiovascular system, the
clinical utility of the analysis of possible candidate genes is
theoretically limited by the fact that the most frequent disorders affecting this system recognize a multifactorial etiology, in which both environmental and behavioral factors
interact dynamically with the function of different genes in
determining the pathophysiological mechanisms that will
lead to the establishment of the cardiovascular disorder. For
this reason, it is impossible to associate single genes’ to specic, persistent clinical conditions, such as acute coronary
syndromes, hypertension, diabetes, and dyslipidemia, which
recognize a complex multifactorial etiology. In these cases,
a “genomic” or “proteomic” approach, rather than a genetic
analysis based on a single gene locus or haplotype, has been
more effectively suggested. The aim would be to dene a
prole or a ngerprint, recognized by molecular analysis or
of the concomitant function of several genes or metabolites
of the same biochemical pathway (gene clustering, expression patterns, proteomic ngerprint, or signature), associated
with a specic cardiovascular disease. The limitations of this
approach are that the analysis is expensive and available in
few laboratories, and the results obtained are often not easily interpretable from a diagnostic and/or prognostic point
of view, so this type of analysis is still not very usable in
clinical practice.
Recently, the interest in studying the relationships
between cardiovascular disease and gene expression has
focused on the study of single-stranded RNAs, which may
be present not only in the nucleus and cytoplasm of cells
but also in the circulation. In particular, the focus has been
on studying microRNAs (miRNAs), a class of small, noncoding RNAs that regulate the expression of complementary RNAs. Altered expression of intracellular miRNAs has
been reported in many diseases, including cardiovascular
diseases. In particular, many studies have recently highlighted the role of some miRNAs not only in some pathophysiological processes affecting the myocardium, such as
brosis, hypertrophy, and angiogenesis, but also in some
complex clinical conditions, such as dilated and hypertrophic myocardial diseases, myocardial infarction, and heart
failure. Being circulating molecules, which can be assayed
in blood samples by laboratory methods, miRNAs represent circulating biomarkers of disease and, therefore, do
not present the limitations of the genomic or proteomic
approach. A list of the most studied miRNAs as risk biomarkers in patients with heart disease is shown in
Table22.4.
Numerous meta-analyses have tried to evaluate the association of some of these circulating miRNAs with frequent
cardiovascular disorders,such as stroke, ischemic heart disease, and heart failure. However, there are still some critical
issues related to their use as biomarkers of cardiovascular
diseases. First, it is not yet evident the relationship between
the gene expression of these noncoding RNAs (e.g., in myocardiocytes) and their respective circulating levels. Moreover,
the methods currently available for their measurement are
not standardized, and there are no internationally agreed
quality specications, so results obtained in different laboratories and by different methods are not comparable. For
these reasons, the identication and determination of these
molecules are applicable only in the elds of pathophysiological and clinical research.
Table 22.4 List of microRNAs (miRNAs) most studied as risk biomarkers in patients with heart disease
MicroRNA
miR-1, miR-19, miR-21, miR-122, miR-126, miR-132, miR-133,
miR-134, miR-140, miR-142, miR-145, miR-146, miR-150,
miR-155, miR-186, miR-197, miR-208, miR-210, miR-223,
miR-320, miR-328, miR-380, miR-451, miR-486, miR-499
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Recommended Readings
Bao MH, Xiao Y, Zhang QS et al (2015) Meta-analysis of miR-146a
Polymorphisms association with coronary artery diseases and ischemic stroke. Int J Mol Sci 16:14305–14317
Barison A, Grigoratos C, Todiere G, Aquaro GD (2015) Myocardial
interstitial remodelling in non-ischaemic dilated cardiomyopathy:
insights from cardiovascular magnetic resonance. Heart Fail Rev
20:731–749
Bettencourt P, Azevedo A, Pimenta J etal (2004) N-terminal-pro-brain
natriuretic peptide predicts outcome after hospital discharge in heart
failure patients. Circulation 110:2168–2174
Braunwald E (2015) The war against heart failure: the Lancet lecture.
Lancet 385:812–824
Calvier L, Miana M, Reboul P et al (2013) Galectin-3 mediates
aldosterone- induced vascular brosis. Arterioscler Thromb Vasc
Biol 33:67–75
Cao W, Guo Q, Zhang T etal (2015) Prognostic value of microRNAs in
acute myocardial infarction: a systematic review and meta-analysis.
Int J Cardiol 189:79–84
Casagranda I, Cavazza M, Clerico A etal (2013) Proposal for the use
in emergency departments of cardiac troponins measured with the
latest generation methods in patients with suspected acute coronary
syndrome without persistent ST-segment elevation. Clin Chem Lab
Med 51:1727–1737
Caselli C, Cangemi G, Masotti S et al (2016) Plasma cardiac tropo-
nin I concentrations in healthy neonates, children and adolescents
measured with a high sensitive immunoassay method: high sensitive
troponin I in pediatric age. Clin Chim Acta 458:68–71
Chen A, Hou W, Zhang Y etal (2015) Prognostic value of serum galec-
tin- 3 in patients with heart failure: a meta-analysis. Int J Cardiol
182:168–170
Cheng C, Wang Q, You W etal (2014) MiRNAs as biomarkers of myo-
cardial infarction: a meta-analysis. PLoS One 9:e88566
Clerico A, Giannoni A, Vittorini S, Passino C (2011) Thirty years of the
heart as an endocrine organ: physiological role and clinical utility
of cardiac natriuretic hormones. Am J Physiol Heart Circ Physiol
301:H12–H20
Clerico A, Passino C, Franzini M, Emdin M (2015a) Cardiac biomarker
testing in the clinical laboratory: where do we stand? General over-
view of the methodology with special emphasis on natriuretic pep-
tides. Clin Chim Acta 443:17–24
Clerico A, Ripoli A, Zucchelli GC, Plebani M (2015b) Harmonization
protocols for thyroid stimulating hormone (TSH) immunoassays:
different approaches based on the consensus mean value. Clin
Chem Lab Med 53:377–382
Clerico A, Passino C, Franzini M, Emdin M (2016) Natriuretic peptides
as biomarkers of cardiac endocrine function in heart failure: new
challenges and perspectives. Futur Cardiol. in press
Cohn JN, Ferrari R, Sharpe N (2000) on behalf of an International
Forum on Cardiac Remodeling. Cardiac remodeling-concepts and
clinical implications: a consensus paper from an international forum
on cardiac remodeling. J Am Coll Cardiol 35:569–582
Condorelli G, Latronico MVG, Cavarretta E (2014) MicroRNAs in car-
diovascular diseases: current knowledge and the road ahead. J Am
Coll Cardiol 63:2177–2187
Curigliano G, Cardinale D, Dent S etal (2016) Cardiotoxicity of anti-
cancer treatments: epidemiology, detection, and management. CA
Cancer J Clin 66:309–325
deFilippi C, Daniles LB, Bayes-Genis A (2015) Structural heart disease
and ST2: cross-sectional and longitudinal associations with echo-
cardiography. Am J Cardiol 115(7 Suppl):59B–63B
Dieplinger B, Mueller T (2015) Soluble ST2in heart failure. Clin Chim
Acta 443:57–70
Emdin E, Clerico A, Clemenza F etal (2005) Consensus document.
Recommendations for the clinical use of cardiac natriuretic pep-
tides. J Cardiovasc Med (Ital Heart J) 6:430–446
Fan D, Takawale A, Lee J, Kassiri Z (2012) Cardiac broblasts, brosis
and extracellular matrix remodeling in heart disease. Fibrogenesis
Tissue Repair 5:15
Franzini M, Lorenzoni V, Masotti S et al (2015) The calculation of
the cardiac troponin T 99th percentile of the reference population
is affected by age, gender, and population selection: a multicenter
study in Italy. Clin Chim Acta 438:376–381
Friões F, Lourenço P, Laszczynska O etal (2015) Prognostic value of
sST2 added to BNP in acute heart failure with preserved or reduced
ejection fraction. Clin Res Cardiol 104:491–499
Biomarkers ofStroke
https://t.me/medicina_free
MarcelloCiaccio andLuisaAgnello
23
Introduction
Several biomarkers involved in the various stages of stroke
pathogenesis (oxidative damage, inammation, thrombus
formation, cardiac function, and brain damage) have been
identied. They could play a role in risk prediction, diagnosis, and differential diagnosis between ischemic and hemorrhagic stroke. However, further studies are needed to validate
their use in clinical practice. This chapter describes the characteristics and potential usefulness of the primary
strokebiomarkers.
abc
Denition ofStroke
The term “stroke” refers to an acute vascular event n the brain.
The World Health Organization (WHO) denes stroke as “a
syndrome characterized by the sudden and rapid development
of symptoms and signs referable to a focal decit of brain
function without any apparent cause other than vascular; the
loss of brain function may be global (patients in a deep coma).
The symptoms last more than 24 h or lead to death;” if the
symptoms last <24h, a transient ischemic attack (TIA) is diagnosed (Fig.23.1). Two types of stroke are distinguished:
Fig. 23.1 CT nding of ischemic (a) and hemorrhagic (b) stroke. MR image of transient ischemic attack (c)
M. Ciaccio (*) · L. Agnello
Department of Biomedicine, Neurosciences and Advanced
Diagnostics, Institute of Clinical Biochemistry, Clinical Molecular
Medicine and Clinical Laboratory Medicine, and Department of
Laboratory Medicine, University Hospital “P.Giaccone”,
Palermo, Italy
e-mail: marcello.ciaccio@unipa.it
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023
M. Ciaccio (ed.), Clinical and Laboratory Medicine Textbook, https://doi.org/10.1007/978-3-031-24958-7_23
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M. Ciaccio and L. Agnello
Table 23.1
subtypes
• Atherosclerosis of the great vessels (embolism/thrombosis)
• Cardioembolism
• Small vessel occlusion (lacuna)
• Stroke from various causes
• Stroke of undetermined causes
– Two or more causes identied
– Negative evaluation
– Incomplete evaluation
Pathophysiological classication of ischemic stroke
• Ischemic stroke, the most frequent form (85%)
• Hemorrhagic stroke (15%)
Ischemic stroke is characterized by altered blood ow to
a brain region, resulting from occlusion or spasm of a cerebral vessel. Table23.1 shows the leading causes of ischemic
stroke.
In hemorrhagic stroke, the lack of perfusion is due to
intracerebral or subarachnoid hemorrhage. The rupture of
deep or supercial parenchymal vessels due to arterial hypertension or amyloid angiopathy, respectively, represent the
primary cause of intracerebral hemorrhage. Subarachnoid
hemorrhage originates from the extracerebral vessels, and
the blood pours into the cerebrospinal uid (CSF); in 85% of
cases, it is caused by an arterial aneurysmrupture.
Stroke is the third leading cause of death in Western countries, after coronary heart disease and cancer, and one of the
leading causes of disability in adults. Mortality at 1 month is
about 20–25%, at 1 year is 30–40%; at 1 year, about onethird of survivors have a high degree of disability. Every
year, in Italy, 157,000 new stroke cases are expected, 196,000
if recurrences are also considered. The prevalence is around
800,000 cases, with an incidence that progressively increases
with age, reaching a maximum value in subjects aged
>65years.
A complex and concatenated series of molecular processes
(oxidative stress, excitotoxicity, endothelial damage, and
blood–brain barrier alteration) follows temporary or permanent focal cerebral ischemia. Numerous factors increase the
risk of stroke (Table23.2), and their recognition constitutes
the basis of both primary and secondary stroke prevention.
TIAs represent a strong risk factor for ischemic stroke,
especially in the rst hours or days after the event. The WHO
denes TIA as “a sudden onset of signs and/or symptoms
related to focal cerebral decit attributable to the insufcient
blood supply, lasting less than 24 h;” in most cases, TIA
resolves within 1 h from the symptomsonset. The ABCD2
(Age, Blood pressure, Clinical features, Duration of symptoms, Diabetes) is a validated score predictive of the early
risk of stroke in patients with TIA; it consists of the sum of
points assigned to ve clinical features independently associated with the risk of stroke:
Table 23.2
Ischemic
stroke
Hemorrhagic
stroke
Risk factors for ischemic and hemorrhagic stroke
Risk factors
Not
modiable Modiable
Age
Genetic
Race
Age
NonCaucasian
race
Hypertension
Heart disease (patent foramen ovale)
Atrial brillation
Diabetes mellitus
Cigarette smoking
Hypercholesterolemia
Reduced physical activity
Excessive alcohol consumption
Obesity
Metabolic syndrome
Use of oral contraceptives
Anti-phospholipid antibodies,
hemostasis factors, elevated Lp (a)
values
Drug use
Hypertension
Excessive alcohol intake
Smoking
Therapy: thrombolytic and
anticoagulant therapy in the acute
phase and in the prevention of ischemic
stroke; antiplatelet therapy only
modestly increases the risk
• Age>60years (1 point)
• Systolic pressure > 140 mmHg or diastolic pressure>90mmHg (1 point)
• Clinical signs of TIA (unilateral hyposthenia, 2 points;
aphasia without hyposthenia, 1 point)
• Duration of TIA (>60min, 2 points; 10–59min, 1 point)
• Diabetes (1 point)
In patients with TIA, the ABCD2 score classies the
2-day stroke risk as:
• Low: score<4
• Moderate: score 4–5
• High: score>5
Hospitalization is indicated in patients with TIA at
moderate- to-high risk of stroke.
Diagnosis andTherapy
The diagnosis of stroke and TIA is typically based on an
accurate anamnesis and a scrupulous physical examination;
in both cases, computed tomography (CT) or magnetic resonance imaging (MRI) is indicated for the differential diagnosis with other pathologies miming TIA or stroke. Moreover,
a CT scan allows differential diagnosis between ischemic
and hemorrhagic stroke; in the former case, it is negative in
the acute phase.
23 Biomarkers ofStroke
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In a subject with suspected stroke, the following laboratory tests are indicated, aimed at assessing the general condition and identifying the risk factors:
• Blood count with platelets
• Glycemia
• Cardiac biomarkers (troponin)
+
• Serum electrolytes (Na+, K+, Cl−, Mg
2
, Ca
+
)
2
• Kidney function tests
• Coagulation tests (prothrombin time [PT], INR, and acti-
vated partial thromboplastin time [aPTT])
• Oxygen saturation
In addition, the following tests are indicated in selected
patients:
• Chest X-ray
• Function prole and liver damage
• Arterial blood gas analysis
• Physical–chemical examination of the CSF
• Lipid prole
• Toxicological investigation
• β-hCG
• Alcohol
• Electroencephalogram
Stroke represents a medical emergency requiring immediate hospitalization. Stroke therapy must be promptlyadministred in the acute phase and will depend on the initial
etiopathogenetic event. In the case of ischemic stroke, the
therapy is thrombolytic and must be started within 4–5 h
from the symptomsonset. In the case of hemorrhagic stroke,
the patient starts a specic therapeutic process, including
neurosurgical evaluation.
In the post-acute phase, physical rehabilitation is of paramount importance.
Biomarkers
• The possibility of being quantitatively and rapidly measured using cost-effective techniques
The difculties in identifying a biomarker to introduce
in clinical practice are mainly related to the slow release of
glial and neuronal proteins across the blood–brain barrier
after stroke or traumatic injury and the reduced diagnostic
specicity (they increase in many clinical situations simulating stroke).
Following cerebral ischemia, there is an increased pro-
duction of oxygen free radicals, which triggers the inammatory response activationthat results in the recruitment
into the damaged brain tissue of various immune cells,
such as macrophages, neutrophils, and T lymphocytes.
These inammatory cells release proinammatory cytokines, such as interleukin-6 (IL-6), which can cross the
blood–brain barrier and reach circulation. In addition,
biomarkers such as D-dimer and those that play a role in
platelet function are involved in thrombus formation and
propagation. The heart and large-caliber vessels, such as
the aorta, are among the main sites of thrombus formation; the inability of the cardiovascular system to release
sufcient blood to the brain may worsen the stroke
outcome.
Several biomarkers have been identied in the various
stages of stroke pathogenesis (oxidative damage, inammation, thrombus formation, cardiac function, and brain damage) (Table23.3).
Other biomarkers currently under investigation are:
• Lipoprotein-associated phospholipase A2 (Lp-PLA2)
• Asymmetrical dimethylarginine (ADMA)
• Matrix metalloproteinase-9 (MMP-9)
• S100-β protein
• N-methyl-D-aspartic acid (NMDA) receptor peptides and
their antibodies
• Glial brillary acidic protein (GFAP)
• Parkinson disease protein 7 (PARK-7)
• Nucleotide diphosphate kinase A (NDKA)
For decades, research has been focused on identifying biomarkers that can improve the earlystroke detection and positively modify the clinical, economic, and management
outcomes. An ideal strokebiomarker should have the following characteristics:
• Diagnostic sensitivity and specicity
• The ability to differentiate between hemorrhagic and
ischemic stroke
• Early and stable release after an acute event
• Predictable plasma clearance
• Potential to dene stroke risk
• The ability to guide therapeutic choices
Lp-PLA2
Lp-PLA2 is a calcium-dependent serine lipase that
hydrolyzes oxidized phospholipids to release proinflammatory lysophosphatidylcholine and oxidized fatty
acids. It circulates bound mainly to low-density lipoprotein (LDL) and partly to small, dense high-density lipoprotein (HDL) (anti- atherogenic effect). Lp-PLA2 is
produced and expressed in macrophage-rich atherosclerotic lesions and represents an independent inflammatory marker of cardiovascular risk and a predictor of
ischemic stroke.
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M. Ciaccio and L. Agnello
Table 23.3
Mechanism and
biomarker Biological function
Inammation
IL-6 Inammatory cytokine that acts as a messenger
CRP Acute-phase protein involved in the inammatory
VCAM-1 Transmembrane protein involved in endothelial
MCP-1 Powerful mononuclear chemoattractant cell
Dyslipidemia/endothelial damage
ApoC-I Associated with LDL and VLDL; involved in
ApoC-III Associated with VLDL, HDL, and LDL; inhibits
NT-proBNP Neurohormone with natriuretic, diuretic, and
FABP Cytoplasmic protein that modulates the cascade of
Growth factors
BDNF Maintenance and survival of mature neurons
Endothelial damage
MBP Main proteolipid constituent of myelin, produced
NSE Dimeric glycolytic isoenzyme in the cytoplasm of
Coagulation/brinolysis
D-dimer Fibrin degradation product; it reects a global
Von Willebrand
factor
Apo apolipoprotein, BDNF brain-derived neutrophic factor, BNP type B
natriuretic peptide, CETP cholesteryl ester transfer protein, CRP
C-reactive protein, FABP fatty acid-binding protein, HDL high-density
lipoprotein, LDL low-density lipoprotein, MBP myelin basic protein,
NSE neuron-specic enolase, MCP monocyte chemoattractant protein,
VCAM vascular cell adhesion molecule, VLDL very low-density
lipoprotein
Biomarkers of stroke according to the pathogenesis
among leukocytes, vascular endothelium, and
resident cells in the parenchyma
response and innate immunity
cell–leukocyte signal transduction
produced by endothelial and smooth muscle cells
plasma lipoproteins remodeling; inhibits CETP
triglyceride hydrolysis by hepatic/lipoprotein
lipase; interferes with physiological endothelial
function
vasodilatory functions
signaling lipid; involved in the oxidation of fatty
acids
by oligodendroglia cells
neurons and neuroendocrine cells
activation of coagulation and brinolysis
Plasma glycoprotein involved in platelet adhesion
degradation of extracellular matrix proteins. It plays an
essential role in several processes, including tissue remodeling, phlogosis, angiogenesis, and metastasis. In the
brain, its expression is physiologically very low or undetectable, while its levels increase signicantly early in the
ischemic brain; in the acute phase, its concentrations correlate with the extent of ischemia, poor prognosis, and
complications from hemorrhagic transformation. Several
studies have highlighted the role of MMP-9 in stroke
pathogenesis, including loss of blood–brain barrier integrity, neuronal death, and hemorrhage following stroke. In
addition, MMP-9 plays a reparative role during brain
regeneration and neurovascular remodeling in the subsequent phase of tissue repair.
S100-β
S100-β is a glial protein consisting of α- and β-subunits that
combine in hetero- and homodimers (α–α, α–β, β–β);
S100-β includes the β–β and α–β forms. It is present in
melanocytes, adipocytes, and chondrocytes but is highly
specic for the nerve tissue, localized in the cerebral astroglial compartment, and Schwann cells, which line peripheral nerve bers. S100-β represents a not specic biomarker
of blood–brain barrier dysfunction with a concentration in
the cerebrospinal uid signicantly higher than in the
serum (40:1). It has emerged as a biomarker of early ischemic stroke with a peak after 24h. It correlates well with
the extent of the infarct area. In addition, it allows differential diagnosis between ischemic and hemorrhagic stroke or
stroke-mimicking diseases. One of the main disadvantages
is its poor specicity, as it increases during other neurological pathologies.
NMDA Receptor Peptides
ADMA
The post-translational methylation of L-arginine produces
the ADMA molecule. After proteolysis, itis released as free
dimethylarginine along with symmetric (inactive) dimethylarginine. It is a potent nitric oxide synthase (NOS)inhibitor.
Its levels are detectable in the blood, urine, and cerebrospinal
uid; the plasma form has been proposed as a predictive
marker of stroke risk.
MMP-9
MMP-9 belongs to the family of zinc- and calciumdependent endopeptidases responsible for the turnover and
NMDA receptor peptides bind glutamate and are present on
neurons throughout the encephalon. They consist of four
subunits, 2 NR1 and 2 NR2. During ischemia, fragmentation of NR2 into NR2A and NR2B and production of antiNR2 antibodies are observed. Therefore, NR2 fragments
and their antibodies represent markers of ischemic stroke
and TIA.
GFAP
GFAP is a monomeric lamentous protein specic to brain
astrocytes. Its levels increase during ischemic stroke, peaking 2–4days after the onset of symptoms. It also allows differential diagnosis between ischemic and hemorrhagic
stroke.
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