Chronic hyperplastic anemia as an independent risk factor for atherosclerotic lesions: a lesson from thalassemia intermedia

Introduction. Cardiovascular involvement represents a well-known complication and the primary cause of mortality, both in transfusion-dependent beta thalassemia major (β-TM) and in transfusion-independent beta thalassemia intermedia (β-TI). In β-TM, heart iron overload is considered the main cause of this complication. This is likely due to poor adherence to iron-chelating therapy, resulting in the inability of the body to efficiently remove iron excess derived from transfused red blood cell breakdown. Different clinical pictures may instead be evoked in cardiovascular involvement occurring in β-TI; however, until now, no factor has emerged as the major one responsible for these complications. Design and Methods. In the present study, iron status, and lipid profiles in serum, as well as lipid content in peripheral blood mononuclear cells (PBMCs) were evaluated in 70 adult β-TM and in 22 adult β-TI patients. Ninety-two age-matched blood donors, free from any form of thalassemia, were utilized as controls. The mRNA levels of genes involved in the regulation of iron metabolism, such as interleukine 1 alfa (IL1α), tumor necrosis factor alfa (TNFα), as well as those involved in cholesterol homeostasis, such as acetyl-coenzymeA: cholesterol acyltransferase (ACAT-1), neutral cholesterol ester hydrolase (nCEH), and ATP binding cassette-A (ABCA1), were also evaluated in PBMCs from the above subjects. Results. In β-TI patients, serum iron, transferrin saturation and erythropoietin levels were higher, while transferrin and hepcidin were lower, compared to both β-TM and controls. Hepcidin and ILα mRNA levels were found to be reduced in β-TI-PBMCs, while those of TNFα were increased. A reduction in total and high density lipoprotein cholesterol (TC and HDL-C) in serum, and an accumulation of neutral lipids (NL), coupled with increased mRNA levels of ACAT-1 and decreased nCEH in PBMCs were also observed in β-TI. Conclusions. Since most of the parameters found to be altered in β-TI patients have a key role in the initiation and progression of atherosclerosis, we suggest that cardiovascular complications in these patients may be, at least partially, dependent on the occurrence of premature atherosclerotic lesions.