Gholamreza Namazi - Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran & Department of Clinical Biochemistry, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran.
Somayeh Heidar Beygi - Department of Clinical Biochemistry, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran.
Mohammad Hasan Vahidi - Department of Clinical Biochemistry, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran.
Parastoo Asa - Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran.
Fereshteh Bahmani - Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran & Department of Clinical Biochemistry, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran.
Alireza Mafi - Department of Clinical Biochemistry, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran.
Fariba Rayegan - Department of Cardiology, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran.

Background: Red blood cell distribution (RDW), an index of the size variability of erythrocytes, is significantly associated with coronary stenosis and can strongly predict the mortality risk in coronary artery disease (CAD). The biological mechanisms involved are not fully understood but may include oxidative stress. We sought to investigate the relationship between RDW and markers of oxidative stress in patients with CAD. Methods: Participants were ۱۱۲ consecutive patients referred to department of cardiac surgery for evaluation of chest pain. ۳۲ patients had stable CAD, ۴۰ patients had unstable CAD and ۴۰ subjects were diagnosed as non-CAD. The levels of lipid peroxidation (TBARS) were measured in plasma and membrane samples by a fluorometric method. The plasma levels of glutathione (GSH) and total antioxidant capacity (TAC) were determined using spectrophotometric methods. Results: Lipid peroxidation levels were significantly higher in the erythrocyte membrane of stable CAD patients than non-CAD patients. The levels of TAC were significantly lower in both stable and unstable groups when compared to that of the control group (P< ۰.۰۱۹ and P< ۰.۰۰۱, respectively), but did not differ between stable and unstable CAD. In addition, there was no significant difference in the serum GSH levels among the study groups. Membrane TBARS was directly associated with RDW in three groups of study. Conclusions: We found an independent association between RDW levels and membrane lipid peroxidation in patients with CAD. This finding suggests that oxidative stress may be a potential underlying biological mechanism for increased RDW in CAD patients.

Coronary stenosis, Oxidative stress, Red blood cell distribution (RDW), Total antioxidant capacity.