Association of GSTT1/GSTM1 and ApoE variants with left ventricular diastolic dysfunction in thalassaemia major patients

Abstract

Background: Cardiomyocytes are particularly susceptible to complications from iron loading. The blood transfusions in thalassaemia major create loading of iron that cannot be naturally excreted. Apolipoprotein E and Glutathione S-transferase act as the scavenger of free radicals, which are generated due to excess iron. The variants of Apolipoprotein E (ApoE) and Glutathione S-transferase (GST) may play a role in oxidative damage-induced cardiomyopathy, so we aimed to study the association of genetic variants of these genes on diastolic dysfunction in our patients. Materials and methods: One hundred and five β-thalassaemia patients older than 10 years were enrolled for the study. Two-dimensional and M-mode echocardiography analysis was done in all patients. Genotyping of the genetic variants of aforementioned genes was done using the PCR–RFLP method. Serum Glutathione S-transferase levels were estimated by ELISA. Results: Diastolic dysfunction was observed in 24 (22.8%) patients, whereas left ventricular hypertrophy was present in 37(35.2%) patients. There was a significant association of GSTM1 null allele with diastolic dysfunction only. Serum GST levels were also positively correlated with e/a and e/e′ ratio. Positive association of ApoE E2 allele with the diastolic dysfunction was also seen. Conclusions: Patients having Glutathione S-transferase M1 allele and Apolipoprotein E E2 allele are predisposed to oxidative stress-induced cardiac injury.