Upregulation of the pro-apoptotic genes BID and FAS in septic shock patients.
BACKGROUND
Lymphocyte apoptosis has been suggested to play a central role in sepsis pathophysiology, and studies in animal models demonstrated that blocking this pathway improves outcome. However, no routine biomarkers of apoptosis are so far available in patients. Thus, the aim of our study was to assess the different biomarkers of apoptosis putatively usable on a routine basis in septic shock.


METHODS
Thirteen septic shock patients (sampled twice between days 1 to 2 and days 3 to 5 after diagnosis of shock) and 15 sex-matched and age-matched healthy controls were prospectively enrolled. Apoptosis was measured in lymphocyte subpopulations using flow cytometry (Annexin-V binding, activated caspase-3 and Bcl-2 expressions). Representative pro-apoptotic and anti-apoptotic gene expressions were assessed by quantitative reverse-transcription PCR. Monocyte HLA-DR expression and lymphocyte subpopulation cell counts were measured as markers of sepsis-induced immune dysfunctions. To test for statistical significance, the Mann-Whitney U test was used with correction by the number of tests performed.


RESULTS
Flow cytometric measurements of apoptosis in septic shock patients showed an increased Annexin-V binding on CD4+ T cells and an increased active caspase-3 expression on B cells only at days 3 to 5 (sixfold change and twofold change, respectively). Gene expression analysis showed an increased BCL-XL mRNA and an upregulation of the pro-apoptotic genes BID and FAS in septic shock patients (10-fold change and fivefold change, respectively) compared with healthy controls.


CONCLUSIONS
The present study highlights the difficulties encountered in monitoring apoptosis on a routine basis in septic patients, whereas in the same sampling conditions and on the same patients, HLA-DR expression and lymphocyte subpopulation cell counts showed characteristics described in the literature. However, pro-apoptotic genes BID and FAS appear to constitute promising apoptosis markers in our hands.
Turrel-Davin
Fanny
F
Joint Unit Hospices Civils de Lyon - bioMérieux, Hôpital Edouard Herriot, 5 place d'Arsonval, 69437 Lyon cedex 03, France. fanny.davin@biomerieux.com
Guignant
Caroline
C
Lepape
Alain
A
Mougin
Bruno
B
Monneret
Guillaume
G
Venet
Fabienne
F
D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D051023:BH3 Interacting Domain Death Agonist Protein / Q000235:genetics / Q000502:physiology*; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D053148:Caspase 3 / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000235:genetics / Q000502:physiology*; D006684:HLA-DR Antigens / Q000235:genetics / Q000502:physiology; D006801:Humans; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012772:Shock, Septic / Q000235:genetics / Q000503:physiopathology*; D015854:Up-Regulation / Q000235:genetics / Q000502:physiology; D019014:fas Receptor / Q000235:genetics / Q000502:physiology*
D017304:Annexin A5; D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; D015415:Biomarkers; C491901:FAS protein, human; D006684:HLA-DR Antigens; D019253:Proto-Oncogene Proteins c-bcl-2; D019014:fas Receptor; D053148:Caspase 3