Effects of uraemia and haemodialysis on neutrophil apoptosis and expression of apoptosis-related proteins.
BACKGROUND
In haemodialysis (HD) patients, it is unclear whether increased apoptosis of neutrophils is due to uraemia or HD itself. The purpose of the current study was to assess the effect of uraemia and HD on the rate of apoptosis and apoptosis-related protein expression in whole blood neutrophils.


METHODS
We employed a whole-blood micromethod to test spontaneous apoptosis and expression of apoptosis-regulating proteins in cultured neutrophils from uraemic patients (pre-HD), HD patients and healthy controls. Blood samples were drawn before, after 20 min and after 4 h of haemodialysis, and were then cultured for 20 h. We evaluated the rate of apoptosis from annexin V and propidium iodide staining, and examined bcl-2, Fas/Apo-1 and p53 expression in the cultured neutrophils.


RESULTS
Fas/APO-1 expression and total percentage of apoptotic whole blood neutrophils of pre-HD and HD patients before HD were significantly higher than controls. There was a transient but significant decrease in the percentage of apoptotic neutrophils and Fas/APO-1 expression after 20 min of dialysis. The expression of bcl-2 protein was significantly lower from neutrophils in HD patients compared with controls, and HD significantly downregulated bcl-2 expression. The p53 protein content in HD patients before HD was significantly higher than in pre-HD patients.


CONCLUSIONS
These findings suggest that uraemia accelerates neutrophil apoptosis by increasing Fas/Apo-1, and that HD does not affect neutrophil apoptosis more than uraemia. In addition, HD produces only in a transient sequestration of potentially apoptotic neutrophils.
Majewska
Ewa
E
Department of Laboratory Diagnostics and Clinical Biochemistry, Medical University, Polish Academy of Sciences, 90-547 Lodz, Zeromskiego 113, Poland. ewamajew@wp.pl
Baj
Zbigniew
Z
Sulowska
Zofia
Z
Rysz
Jacek
J
Luciak
Marek
M
D017209:Apoptosis / Q000502:physiology*; D005260:Female; D019254:Genes, bcl-2 / Q000502:physiology; D006801:Humans; D007154:Immune System Diseases / Q000209:etiology / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000502:physiology*; D014176:Protein Biosynthesis; D006435:Renal Dialysis / Q000009:adverse effects*; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis; D014511:Uremia / Q000276:immunology* / Q000503:physiopathology; D019014:fas Receptor / Q000096:biosynthesis
D016159:Tumor Suppressor Protein p53; D019014:fas Receptor