Zahid, Azfar (2016) Characterisation and cellular uptake of non-transferrin bound iron species; implication for the dignosis and monitoring of iron overload diseases. (MSc(R) thesis), Kingston University, .

Abstract

Background: Non-transferrin bound iron (NTBI) is a form of 'free' iron that appears in iron overload diseases when the binding capacity of the transport protein transferrin is exceeded. NTBI has three known forms: albumin bound, complexed with citrate, and labile iron (LI). NTBI is taken up by the liver more rapidly than transferrin bound iron, and in its labile form can cause organ damage through the production of reactive oxygen species (ROS). An understanding of the effect of albumin and citrate on the formation of labile iron, and of the cellular uptake of different NTBI species, may help identify potential biomarkers for the diagnosis and treatment of iron overload. Aims: To characterise the formation of NTBI species by measuring LI in aqueous, albumin and citrate iron solutions, and to quantify the uptake of these NTBI species by cultured HepG2 cells. Methods: LI was measured by monitoring fluorescence generated in the presence of ascorbic acid and dihydrorgodamine. HepG2 cells were cultured in media containing varying concentrations of LI species, harvested, and total iron content quantified using a ferrozine based method. Results: Albumin (9.6g/L) and citrate (10.0mmol/L) significantly reduced levels of LI to 23% and 40% of total iron respectively (p < 0.01 for both). Albumin-bound and citrate-bound NTBI species were taken up by HepG2 cells at reduced rates (80% and 62%, p <0.01) compared to LI. Conclusion: The binding of iron by albumin and citrate provide some protection against the formation of LI. LI is taken up by cells more rapidly than other NTBI species and is therefore potentially more toxic. LI should be measured in preference to toal NTBI when investigating iron overload diseases.

Actions (Repository Editors)

Item Control Page