Erythrocyte membrane protein alteration in diabetics.

Abstract

To study the protein components of the erythrocyte membranes of diabetic Nigerians and to compare the results with the erythrocyte membrane protein components of normal healthy Nigerians. Laboratory based cross-sectional study. Department of Medicine, University College Hospital (UCH), Ibadan and Biomembrane Research Laboratory, Department of Biochemistry, College of Medicine, University of Ibadan, Ibadan, Nigeria. The study was carried out in patients with insulin-dependent diabetes mellitus--IDDM (Type 1 diabetes), non-insulin dependent diabetes mellitus--NIDDM (Type 2 diabetes) and healthy human volunteers (HHm), which served as controls. The subjects were aged 30-65 years. There were 12 subjects in each of the IDDM and NIDDM) and 18 subjects in the HHm group. Blood samples (20 ml per subject) were obtained from each subject and erythrocyte ghost membranes were isolated separately from each sample. Total erythrocyte membrane protein concentration of each sample was determined using bovine serum albumin (BSA) as standard. The protein components of the erythrocyte ghost membranes were determined using sodium dodecyl sulphate polyacrylamide gel electrophoresis. All values given are the mean +/- standard deviation (+/- SD) of the parameters measured. Significance was assessed using Student's t-test and P values of 0.05 or less were taken as statistically significant. The total protein concentration of HHm was 5.5 +/- 0.01 micrograms/ml, total protein concentration of IDDM was 4.5 +/- 0.01 micrograms/ml while NIDDM was 5.1 +/- 0.02 micrograms/ml. The spectrin alpha and beta-chain bands are heavily present in the healthy human erythrocyte membranes and are absent in the insulin dependent diabetic membranes. The ankyrin band, band six and below are more pronounced in IDDM and NIDDM but are relatively absent in the healthy humans. The results obtained provide evidence of profound quantitative and qualitative alteration of the erythrocyte membrane proteins in diabetic Nigerians. This may likely have serious functional implications of the diabetic patients.