Scientific Research and Essays Vol. 6(9), pp. 1957-1962, 4 May, 2011 Available online at http://www.academicjournals.org/SRE ISSN 1992-2248 ©2011 Academic Journals Full Length Research Paper Evaluation of N ε -(carboxymethyl)lysine and lipid peroxidation in multiethnic Malaysian subjects with type 2 diabetes mellitus Khaled Abdul-Aziz Ahmed 1, 2 *, Sekaran Muniandy 1 , Ikram Shah Ismail 3 , Reyadh Saif Ali 1 , and Zaid Hizam Alhamodi 1 1 Department of Molecular Medicine, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia. 2 Faculty of Dentistry, Ibb University, P.O.Box 70627, Ibb, Yemen. 3 Department of Endocrinology, University of Malaya Medical Center, University of Malaya, 50603 Kuala Lumpur, Malaysia. Accepted 4 March, 2011 The glycoxidation product, N ε -(carboxymethyl)lysine (CML), is formed during reaction of glucose with protein under oxidative conditions. The aim of the study was to evaluate the levels of the most common glycoxidation product; N ε -(carboxymethyl)lysine (CML) and the most advanced lipoxidation product, malondialdehyde (MDA) in type 2 diabetic Malay, Indian, and Chinese ethnic groups in the Malaysian population. Studies were performed on age-matched Malay, Indian, and Chinese subjects with type 2 diabetes mellitus. Different biochemical parameters including serum levels of CML, MDA, lipid profile, glucose, and hemoglobin A1c (HbA 1c ) were measured by standard methods. The relationships between circulating CML and lipids, HbA 1c , and MDA, were examined. Correlation studies between CML, lipids, HbA 1c , and lipid peroxidation were performed. CML and MDA levels were significantly higher in Malay subjects than in Indian or Chinese patients (p <0.005). A significant difference was also observed in the levels of serum total cholesterol and LDL-cholesterol (p <0.05) between the groups in the study. A positive correlation was observed between serum levels of CML and MDA in Malay diabetic patients, but no such correlation was seen in either the Chinese or Indian populations. The results of this study demonstrate that ethnicity affects CML and MDA circulating levels in Malaysian subjects with type 2 diabetes mellitus. Key words: Type 2 diabetes mellitus, N ε -(carboxymethyl) lysine, lipoxidation, multiethnic Malaysian subjects. INTRODUCTION Type 2 diabetes is the most common form of diabetes comprising 80 to 90% of all diabetic people. Type 2 diabetes mellitus (T2DM) is a global health problem affecting approximately 4.0% of adults in the world in 1995 (Harris et al., 1998) and this prevalence has been projected to increase to 5.4% by 2025 (King et al., 1998). Epidemiological data have considered hyperglycemia to be a major player in the development of macrovascular complications such as coronary artery disease (CAD) and stroke (Laakso, 1999). Macrovascular complications of *Corresponding author. E-mail: khaaah@gmail.com. diabetes mellitus (DM) are due to accelerated athero- sclerosis and have an important role in the increased morbidity and mortality suffered by these individuals (Wingard and Barrett-Connor, 1995). For example, a recent meta-analysis study showed that the rate of fatal CAD is higher in diabetic patients than in non-diabetic individuals (5.4% vs. 1.6%) (Huxley et al., 2006). Diabetes causes oxidative stress, not only due to the increased production of mitochondrial reactive oxygen species (ROS) or an impaired endogenous capacity to scavenge free radicals (Brownlee, 2001), but also due to glucose auto-oxidation (Wolff et al., 1991), and to the non-enzymatic glycation of proteins (Brownlee, 2000). In vivo glycation and lipid peroxidation reactions may play a