INTRODUCTION
BTM is an autosomal recessive disease characterized by hemolytic anemia
in which one or more of the hemoglobin beta chain is produced
defective.1 Regular erythrocyte transfusion is
required to prevent clinical complications due to low hemoglobin
levels.2 However, increased iron load accumulated in
the body as a result of frequent erythrocyte transfusions leads to many
organ damage, including endothelial dysfunction and cardiovascular
complications.3,4 Peroxidative damage due to iron load
caused by repeated blood transfusions and possible coronary artery
diseases are thought to be responsible for the
pathogenesis.5,6 Vascular and cardiac complications
are based on endothelial dysfunction and altered carotid artery
structure, which are present in the nature of
thalassemia.3
It has been shown in many studies in the literature that the
arginine-nitric oxide pathway triggered by hemolysis causes endothelial
function7,8. NO is a mediator that controls vascular
tone by vasodilation, causes thrombocyte dysfunction, prevents the
adhesion of leukocytes, and reduces vascular intimal cell
production.9 NO is synthesized from the endothelium by
converting L-arginine to L-citrulline by endothelial NO synthase (eNOS),
whose activity is dependent on nicotinamide adenine dinucleotide
phosphate. 10 The addition of two methyl radicals to
arginine by the action of methyltransferase nuclear proteins leads to
the production of ADMA, which competes with L-arginine and reduces NO
formation in the vascular wall.11 High ADMA levels
inhibit NO synthesis. Thus, it disrupts the endothelial function and
supports atherosclerosis. ADMA has been recognized as an early marker
for endothelial dysfunction and also as an independent factor for future
cardiovascular disease.12,13
Endocan (formerly known as endothelial cell specific molecule-1, ESM-1)
is a 50 kDa soluble proteoglycan that can be detected in circulation and
is synthesized in vascular endothelial cells in many
organs.14 It shows its effect by regulating the
adhesion rate of cells to the vascular wall. High levels of endocan
indicate endothelial dysfunction.15 Apart from that,
it plays a role in cell migration, adhesion, proliferation and
neovascularization, which are biologically
indispensable.16
Considering this information, in our study, it was aimed to determine
whether there is a correlation with cardiac evaluation instruments by
evaluating circulating ADMA and endocan levels in transfusion-dependent
BTM patient group and healthy control group and whether they can be a
prognostic marker in terms of endothelial dysfunction and cardiovascular
risk stratification.