Lower levels of serotransferrin, the blood protein that transports iron through the body, are an early indicator of coronary artery disease (CAD) and can help identify heart conditions earlier than routine clinical diagnoses, say scientists.
NEW DELHI — Lower levels of serotransferrin, the blood protein that transports iron through the body, are an early indicator of coronary artery disease (CAD) and can help identify heart conditions earlier than routine clinical diagnoses, say scientists.
Iron deficiency is prevalent in patients of CAD, a common cardiovascular condition characterised by a narrowing of the coronary arteries due to atherosclerosis, primarily resulting from an accumulation of plaque or fatty deposits. An analysis of blood serum proteins by Delhi’s Centre for Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB) has revealed the critical role of serotransferrin in identifying cardiac disease.
"Serotransferrin may have value as an early diagnostic marker, meaning it could potentially help identify CAD earlier than routine clinical diagnosis," Sagarika Biswas, corresponding author on the study, told PTI.
A deeper understanding of how CAD develops is crucial for developing effective diagnostics and therapeutics, the IGIB researchers said. Serotransferrin, found in previous studies to contribute to CAD, presents a potential avenue for investigation, they said.
Exploring molecular and cellular processes related to serotransferrin may help shed light on how CAD develops and identify new targets for treatment, the team said.
"Of the total 197 differentially expressed proteins, serotransferrin (TF), an iron transporter, showed downregulation in samples from CAD patients compared to healthy," the authors wrote in the study published in the journal Acta Cardiologica. Downregulation means lower than normal levels
The study, involving 50 CAD patients and 40 healthy people, also showed an increased level of the cardiac marker 'troponin I' among those affected by the heart disorder, demonstrating an inverse relationship with serotransferrin levels.
Troponin I is a specialised protein present in heart muscle cells, a damage or injury to which causes the protein to leak and enter the bloodstream.
"TF (serotransferrin) protein was significantly associated with CAD progression and inversely correlated with cTnI (troponin I), suggesting it (serotransferrin) could be a potential therapeutic target pending further molecular and clinical investigation," the authors said.
Longitudinal studies would be required to estimate the duration in years before which serotransferrin could help identify CAD, explained Biswas, former distinguished chief scientist and professor at CSIR-IGIB's department of integrative and functional biology.
The study linked reduced levels of serotransferrin with the inflammatory environment created due to damage in the inner lining of arteries, which leads to an immune response against the accumulated fatty deposits.
According to Biswas, worsening ischaemia -- local anaemia due to a reduced blood flow caused by narrowed or blocked vessels -- and tissue injury can increase troponin I, whereas inflammatory and metabolic stress may suppress serotransferrin expression or availability in CAD.
Further, levels of serotransferrin can reflect iron status in an individual.
"In standard iron studies, transferrin saturation below 20 per cent is commonly taken as evidence of iron deficiency, meaning less than 20 per cent of transferrin's binding sites are occupied by iron," Biswas said.
Transferrin refers to the family of iron-binding proteins, while serotransferrin is a subtype found in blood serum and plasma. A region on a protein's surface to which another molecule attaches itself is a binding site.
"Serotransferrin is an iron-transport protein, so a lower level suggests (a) reduced iron-binding and transport capacity. The protein may contribute to the functional iron deficiency component of CAD by limiting plasma iron transport, but the study did not quantify its contribution as a percentage," Biswas said in response to a question.