Interaction of Human Serum alpha-1-Antitrypsin and Low Density Lipoprotein a Perspective to the Relation of Liver and Heart diseases

Alpha-1-antitrypsin (AAT) is one of the important plasma antiserins proteases. This protein is the major inhibitor of leucocytes elastases and plays a crucial role in protecting the pulmonary tissue from elastolytic destruction. ApoB100, is an apoprotein that exist in the low density lipoprotein, and provides structural integrity and functions as a ligand mediating the cellular association and uptake of LDL-C by tissues. Alpha 1-antitrypsin and apoB100, are two proteins that are produced in the liver, can be bound to each other in serum, and affect LDL-C uptake by tissues. In the present study, 21 serum for the formation of AAT-LDL complex were investigated initially. All samples were phenotyped by use of isoelectrofocusing using standard serua. We also determined LDL-C level and lipid profile by enzymatic method. Sera AAT activities (TIC) were measured by spectrophotometric method by the use of trypsin enzyme and BAPNA as substrate. The AAT-LDL complex in samples with different LDL-C and AAT activities, was investigated by sandwich ELISA method using anti-apoB antibody and anti AAT monoclonal antibody. The results of this study showed that the AAT-LDL complex is formed in serum with normal and abnormal AAT phenotypes and these preliminary data indicated the different level of complex in different samples. The average of the complex absorbance was 65% in all samples. This showed that at least a part of AAT and LDL interacted with an acceptable concentration. It has been concluded that AAT-LDL complex level in sera of patients with liver disease due to AAT deficiently may correlate with the atherosclerosis. Further studies are needed to show the association of AAT and LDL-C and AAT-LDL complex formation, in various diseases specially heart and liver diseases.