The reduction of cholesteryl linoleate in lipoproteins: an index of clinical severity in beta-thalassemia/Hb E.

Abstract

BACKGROUND:

Oxidative modification of lipoproteins has been reported in beta-thalassemia and has been suggested to relate to atherogenesis-risk. This study focused on the change in cholesteryl esters in plasma lipoproteins under oxidative stress resulting from iron overload in beta-thalassemia/hemoglobin E (beta-thal/Hb E) patients.

METHODS:

Markers of oxidative damage and cholesteryl esters (CEs) were measured in plasma and lipo-proteins from 30 beta-thal/Hb E patients and compared to those from 10 healthy volunteers. CEs in plasma, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) were separated and identified using HPLC.

RESULTS:

beta-Thal/Hb E patients presented iron overload, a precipitous decrease in alpha-tocopherol and increased lipid peroxidation (thiobarbituric acid-reactive substances; TBARs) in both plasma and lipoproteins. Cholesteryl linoleate, the most abundant CE in lipoproteins, showed a reduction of 70% in LDL, while other CEs showed a lower reduction (50%). An inverse relationship between the cholesteryl linoleate/cholesteryl oleate ratio (CL/CO) and the degree of clinical severity suggested that the CL/CO ratio is an index of damaged lipoproteins and could be used as a pathologic marker of underlying iron overload. Good correlation of non-transferrin-bound iron (NTBI) and TBARs (r=0.8, p<0.01) in LDL strongly supported the contention that iron overload is responsible for initiating the lipid peroxidation in beta-thal/Hb E.

CONCLUSIONS:

This study suggests that cholesteryl linoleate is the primary target of oxidative modification induced by NTBI in beta-thal/Hb E patients and that reduction in cholesteryl linoleate in lipoproteins could be used as a severity index for beta-thal/Hb E.

• Authors: Rataya Luechapudiporn, Noppawan Phumala Morales, Suthat Fucharoen, Udom Chantharaksri
• Journal: Clinical chemistry and laboratory medicine (Clin Chem Lab Med) Vol. 44 Issue 5 Pg. 574-81 ( 2006) ISSN: 1434-6621 [Print] Germany
• PMID: 16681427 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Cholesterol Esters
• Lipoproteins
• cholesteryl linoleate
• Hemoglobin E
• alpha-Tocopherol
• Oxygen

Topics

• Adolescent
• Adult
• Case-Control Studies
• Chemistry, Clinical (methods)
• Child
• Cholesterol Esters (chemistry)
• Female
• Hemoglobin E (metabolism)
• Humans
• Lipid Peroxidation
• Lipoproteins (chemistry, metabolism)
• Male
• Middle Aged
• Oxidative Stress
• Oxygen (metabolism)
• alpha-Tocopherol (metabolism)
• beta-Thalassemia (metabolism)