Protein composition and functional parameters of RBC membranes in liver and kidney transplantation

Abstract

Organ transplantation is an effective treatment for many end-stage diseases. However, reperfusion injury constitutes a major complication of transplantation, which is associated with microcirculatory disorders and aggregation of blood corpuscles. Red blood cells (RBC) play an essential role in maintaining hemodynamic and rheological properties of the blood. Moreover, the study of mechanisms of changes in RBC functional indices is an urgent task. The main indicator of RBC functioning is the stability of RBC membrane structure. The issue of RBC membrane modification in organ transplantation has not been studied so far. Objective: to study the protein composition of RBC membranes, their aggregation and electrokinetic parameters in liver and kidney recipients, as well as in related kidney and liver fragment donors before and after operation. Research materials. Blood of 12 kidney recipients and 5 related kidney donors, 8 liver recipients and 4 related liver fragment donors – 1–2 hours before surgery, 1 week, 1, 2, 7, 10, 12 months after surgery. The control group consisted of 8 healthy volunteers. Research methods. Protein separation was done by Laemmli electrophoresis. RBC electrophoretic mobility, which characterizes the electrokinetic properties of cells, was measured by microelectrophoresis. Aggregation was calculated microscopically by counting unaggregated RBCs. Obtained values were compared by Mann-Whitney U test. Results. Examination of the RBC membrane of kidney recipients revealed a significant decrease in the amount of Band 3 protein and glycophorin before and after transplantation. Band 3 protein levels reduced at 1 month, glycophorin reduced at 7 months after surgery, with a maximum decrease in these protein fractions by more than 50% by 7 days compared with control values. There was also a decrease in spectrin content for 2 months after surgery with a maximum decrease of 30% by 1 month. In liver recipients, analysis of RBC membrane proteins revealed a decrease in the amount of glycophorin before surgery and further decrease at 2 months of post-transplant period. The maximum decrease in this index was 72% by 7 days after surgery. In addition, there was a fall in spectrin and Band 3 protein levels at 1 month by more than 60% relative to the control values. In donors, there were changes in the protein fraction of RBC membranes in the long-term post-operative period: spectrin and Band 3 protein levels reduced by 2 times at month 2 in kidney donors, while glycophorin levels reduced by 2.3 times at month 1 after operation in liver donors. Similarly, both groups of donors had increased actin levels at month 1 after surgery. The revealed changes in protein levels in the protein phase of RBC membranes were combined with functional indices of RBCs. In kidney recipients, decreased RBC electrophoretic mobility and increased aggregation were detected at 2 months. In liver recipients, the changes in these indicators were at 1 month. A decrease in RBC electrophoretic mobility was detected in donors of both groups. Conclusion. Changes in RBC membrane electronegativity are associated with changes in glycophorin and Band 3 protein levels, whereas in RBC aggregation process in liver/kidney recipients, the structural and functional disorders in the interrelationships of such membrane proteins as spectrin, Band 3 protein, and glycophorin, are significant factors. Alteration of actin determines inhibition of RBC aggregation growth in donors.