Impact of lipid apheresis on Egr-1, c-Jun, c-Fos, and Hsp70 gene expression in white blood cells

Lipid apheresis treatment has been suggested to cause oxidative stress. Cells respond to oxidative stress in many ways, including, among others, altered gene expressions. In the present investigation we investigated whether the gene expression of known stress genes was affected in the WBCs of patients undergoing lipid apheresis. For this purpose cellular early-growth-response gene-1 (Egr-1), c-Jun, c-Fos, and heat shock protein 70 (Hsp70) mRNA expression was followed before and immediately after lipid apheresis treatments (N=24). Gene expression was determined by quantitative reverse transcription-polymerase chain reaction. With the exception of c-Fos, the expression of Egr-1, c-Jun, and Hsp70 mRNA was not affected in WBCs by a single lipid apheresis treatment (median [16th percentile; 84 th percentile]): Egr-1, before 0.30 (0.13; 0.53), after 0.31 (0.14; 1.33); c-Jun, before 0.03 (0.03; 0.16), after 0.05 (0.03; 0.18); Hsp70, before 0.49 (0.23; 1.07), after 0.53 (0.20; 1.61)). Expression of c-Fos was significantly decreased (P<0.01) after lipid apheresis treatment (before 2.18 [1.06; 5.27], after 1.65 [0.74; 4.12]). Hsp70 and c-Fos expression in lipid apheresis patients was not different from that in 35 healthy blood donors, whereas Egr-1 and c-Jun were significantly decreased (P<0.05) in lipid apheresis patients when compared to controls (Egr-1 0.96 [0.42; 1.83], c-Jun 0.64 [0.40; 0.98], c-Fos 2.77 [1.32; 4,02], Hsp70 0.43 [0.28; 0.61]). These results show that lipid apheresis procedures do not induce stress gene expression in WBCs. Therefore, all the lipid apheresis systems used seem to be safe with respect to oxidative stress and other injuries induced in WBCs due to contact with extracorporeal tubing and membranes.