Comparison of Different Electrophoretic Methods for Haptoglobin Phenotyping and an Investigation in Patients with Abdominal Aortic Aneurysm
Haptoglobin is an acute phase protein with important biological role because of its capacity to bind to haemoglobin. Haptoglobin exists in three major genetic polymorphism types: Hp1-1, Hp2-1 and Hp2-2, the distribution of which has been associated with abdominal aortic aneurysm (AAA), an asymptomatic aortic disease common among men older than 65 years. Five different electrophoretic methods were tested according to their ability to separate the haptoglobin phenotypes. The detection was based on a produced hemolysate of blood in which haemoglobin binds to haptoglobin thereby forming a complex that can be detected by specific haemoglobin staining using TMB-dihydrochloride and hydro peroxide as substrate resulting in an azure-green color of the bands. Samples from 15 patients who had suffered surgery for not broken AAA, that is more than5.0 cmaortic diameter, and 15 samples from matched controls were analyzed. Among the five tested electrophoretic methods best migration and separation was seen on the pre-cast agarosgel Hydragel HR on the instrument Hydrasys. The other four methods gave less successful results. This pilot investigation showed the following distribution of the phenotypes of haptoglobin among AAA patients; 7 % Hp1-1, 40 % Hp2-1 and 53 % Hp2-2 and for the controls; 13 % Hp1-1, 33 % Hp2-1 and 53 % Hp2-2. In conclusion, the used techniques has to be further optimized and more patients have to be included in the study before it can be ascertained if the phenotypes of Haptoglobin play any role in the progress of the AAA disease.