Clinical Trial Details
— Status: Not yet recruiting
Administrative data
| NCT number |
NCT01442350 |
| Other study ID # |
Fabry-Myocardial |
| Secondary ID |
|
| Status |
Not yet recruiting |
| Phase |
N/A
|
| First received |
September 26, 2011 |
| Last updated |
September 27, 2011 |
| Start date |
October 2011 |
| Est. completion date |
April 2013 |
Study information
| Verified date |
September 2011 |
| Source |
Hospital Universitario Virgen de la Arrixaca |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
Spain: IRB Hospital Virgen de la Arrixaca |
| Study type |
Observational
|
Clinical Trial Summary
The cardiac variant of the Fabry disease is a rare cardiomyopathy affecting 1/50000
individuals in general population. It is generally diagnosed in advanced stages of the
disease, because it presents clinical features very similar to the hypertrophic
cardiomyopathy ones, making difficult the correct diagnosis. In Fabry disease there is a
remodeling process of the myocardial interstitium and apoptosis of myocytes which leads to
fibrosis development and later systolic dysfunction. The investigators propose to evaluate
the utility of several biomarkers in the diagnosis of this cardiomyopathy, to facilitate the
early diagnosis, which is clue to establish early enzyme replacement therapy or intensify
the patients' follow up. In order to achieve this objective, the investigators will analyze
markers of endothelial dysfunction, fibrosis and apoptosis in peripheral blood samples of
patients carrying the mutation but without clinical manifestations and the investigators
will compare their levels with dose obtained from two different control groups: diagnosed
patients presenting clinical manifestations or index cases and healthy controls without
carrying the mutation.
Description:
Fabry disease is an X-linked recessive disease, affecting lysosomal storage with a variable
phenotype characterized by the accumulation of glycosphingolipids in several tissues. It has
been described more than 200 mutations in the alfa-galactosidase A (GLA) gene which cause
Fabry disease. Nowadays, the treatment of Fabry disease consists of enzyme replacement
therapy (ERT) which development has shown a reversal of abnormal accumulation of
glycosphingolipids in different tissues and a clinical improvement or stabilization (1).
Unlike classic systemic Fabry disease with multiple organ affectation, the cardiac variant
of the disease is characterized by myocardial hypertrophy. Hence, cardiac Fabry variant is
defined as a storage myocyte disorder mimicking the clinical features of the hypertrophic
cardiomyopathy (HCM)(2).
The gold standard for the diagnosis of Fabry disease is the electron microscopy evaluation
of cardiac samples obtained from endomyocardial biopsy (2), although it has been published
that the determination of the alfa-galactosidase activity in plasma of patients diagnosed of
Fabry disease, followed by sequencing of the GLA gene in those individuals with low activity
level is a good non-invasive diagnostic method which allows the identification of the
disease carriers and the early start of the enzymatic replacement therapy (3).
Due to the similarity between clinical characteristics of both diseases and to the
extraordinary low incidence of the Fabry disease, the biopsy execution is rarely carried out
for diagnosis. Hence, it has been speculated that a higher disease incidence should exist
hidden among patients presenting with clinical symptoms of HCM. Several studies have
evaluated the incidence of the Fabry disease among patients diagnosed of HCM, finding out
that even 8-10% of these patients actually presented Fabry disease (4,5), although a bias in
the patient selection can exist. In more recent studies including one carried out by our
group with a higher number of patients, a lower incidence (between 1-3%) has been found
(3,6). So, Fabry is a rare disease affecting 1/50000 individuals in the population (3).
Extracellular matrix is a dynamic structure with an intense participation in the myocardial
remodeling that occurs in different cardiovascular diseases (7). Alterations in the
extracellular matrix could perform an important role in the diastolic dysfunction process
linked to the myocardial hypertrophy. Collagen deposits increase left ventricular chamber
stiffness and ventricular load during diastole is compromised. Collagen turnover is
increased when compared to healthy controls, and synthesis is predominant over degradation,
finding associated changes in metalloproteinase activity (MMP, which are the principal
enzymes in charge of matrix degradation) and their inhibitors (TIMP) (8). Our group has
recently published several papers about the relevance of the fibrosis in patients with MCH
(9,10,11,12). The investigators found out that fibrosis, assessed by late Gadolinium
enhancement in cardiac magnetic resonance, is related to ventricular remodeling,
hypertrophy, ventricular tachycardia (10) and functional state of the patient (11) and that
MMP-9 value is independently associated to fibrosis (9). There are also studies describing
structural changes in the matrix associated to Fabry disease, where fibrosis presence is
evident both at the interstitial level and replacing myocardiocytes loss (13). However, it
has not been yet demonstrated whether the alteration in the interstitial matrix takes place
due only to fibroblasts activation in response to humoral or mechanical factors without
myocardiocytes loss or, on the contrary, it is associated to cellular death.
The interest of apoptosis, or programmed cell death, is increasing in heart failure.
Apoptosis can be activated by the interaction of cell surface death receptors (i.e.
receptors of tumoral necrosis factor superfamily -TNFR- and Fas protein receptor), with its
ligands (TNF-alfa and Fas ligand, FasL) (14), and by activation of the mitochondrial
pro-apoptotic mechanisms, in response to unfavorable changes in intracellular environment
(15). The subsequent development is regulated by the Bcl-2 protein group (16) and executed
by the caspase family (17). During the apoptosis, Annexin 5, is produced in the myocytes and
secreted to the interstitial space (18,19). Annexin 5 seems to contribute to the
intracellular calcium management alteration, leading to the systolic dysfunction (20, 21).
Myocardiocytes death via apoptosis could be a more common process that previously thought,
with estimation of repair process that contribute to the interstitium expansion. GDF-15 is a
member of the TGF-β superfamily, and a well establish marker of risk and prognosis in acute
coronary syndromes. It has been recently proposed as a regulator of fibrosis and tissue
remodeling processes probably by prevention of apoptosis (22). Apoptosis of myocardiocytes
leads to the progressive ventricular wall slimming, as previously reported in MCH (23), and
systolic dysfunction.
Many of the molecules involved in apoptosis and ventricular remodeling can be detected in
peripheral blood and are known as biomarkers. Biomarkers give information about normal
biological processes or physiopathologic mechanisms and can be very useful in differential
diagnosis or even in prognosis. Nowadays, there is a raising interest in the study and
utility of biomarkers in cardiovascular disease, being more used in ischemic cardiopathy and
heart failure (24-27). Unfortunately their study in HCM has been less developed, even less
in Fabry disease. Brain natriuretic peptide (BNP) is the most studied biomarker in HCM and
has been related to the presence of heart failure symptoms (28-30), poor functional capacity
(30) and left ventricular outflow obstruction (31-34). On the other hand ST2 has started
very recently to be considered as a good biomarker for myocardial-specific response to
stretch, with synergistic implications in prognosis with BNP (35).
Our group is currently developing a project studying several biomarkers (myocardial stress,
endothelial damage, hypercoagulable state) in order to explore different systems involved in
ventricular remodeling in HCM (assessed by echocardiography and cardiac magnetic resonance)
that could be very similar in Fabry disease.
In Fabry disease, plasma or urine level of globotriaosylceramide (Gb3) is used as biomarker.
This glycosphingolipid is stored in lysosomes in Fabry patients, although is has been shown
that detected plasma or urine concentrations can vary, due to different mutations that do
not provoke a complete loss of alfa-galactosidase activity. In addition, in heterozygous
women plasma levels can be normal but there are some data suggesting high concentration in
urine (36). On the other hand, it has been suggested that is lactosylceramide, a catabolic
product of Gb3, who regulates the expression pattern of TNF-alfa and y ICAM-1, contributing
to atherosclerosis development (37).
The investigators dispose of a specialized cardiomyopathy clinic in each of the three
hospitals: Hospital Universitario Virgen de la Arrixaca, Murcia, Hospital General
Universitario de Alicante, and Hospital General Universitario de Elche. The investigators
have already recruited 12 families with diagnosed Fabry probands and a total of 60 relatives
clinically checked up within last 4 months. The investigators consider that the recruitment
of patients has been successful and are ready to carry out the present project. However, the
investigators would like to participate with other centres in order to share patients and
mutated relatives without phenotypic disease expression.
The aim of the present project is to study biomarkers of apoptosis, fibrosis and
interstitial remodeling in peripheral samples of patients diagnosed with Fabry disease and
relatives. Our objective is to establish whether exists or not myocardial affectation data
in mutations carriers without phenotypic disease criteria. The investigators will also focus
on different polymorphisms and their implication in the development of Fabry disease.
