Neuraminidase alters red blood cells in sepsis.
OBJECTIVE
To investigate the influence of neuraminidase, an enzyme that cleaves sialic acid from the red blood cell (RBC) membrane, on RBC shape and biochemistry in critically ill patients.


METHODS
Prospective, observational study and in vitro laboratory study.


METHODS
A 31-bed medico-surgical department of intensive care and a university-affiliated cell biology laboratory.


METHODS
Acutely ill patients with and without sepsis and healthy volunteers.


METHODS
Blood sampling in volunteers.


RESULTS
Neuraminidase activity was measured using a fluorescent assay. RBC shape was assessed by the second coefficient of dissymmetry of Pearson using a flow cytometry technique at 25 degrees C. Intraerythrocytic 2,3-diphosphoglycerate and lactate contents were also measured. Neuraminidase activity was significantly higher in septic patients compared with nonseptic patients and healthy volunteers (5.42 [4.85-6.00] vs. 4.53 [4.23-5.23] and 1.26 [0.83-1.83] mU/mL; all p < 0.05). Neuraminidase treatment modified the RBC shape in vitro in a dose-response fashion, and most of these alterations were present after 10 hours of incubation. Incubation of RBCs with phosphatidylinositol phospholipase C modified RBC shape and increased sialic acid concentrations in the supernatant, suggesting a leakage of neuraminidase from the RBC membrane. Alterations in shape were associated with increased 2,3-diphosphoglycerate (0.46 +/- 0.25 vs. 0.19 +/- 0.05 mumol/mL; p = 0.006) and lactate content (0.81 +/- 0.07 vs. 0.66 +/- 0.05 mmoL/L; p = 0.002).


CONCLUSIONS
In sepsis, desialylation under the influence of increased neuraminidase activity may contribute to the alterations in RBC rheology. Inhibition of neuraminidase may represent a new therapeutic option to ameliorate RBC rheology and perhaps oxygen delivery to the cells.
Piagnerelli
Michael
M
Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium.
Boudjeltia
Karim Zouaoui
KZ
Rapotec
Alessandro
A
Richard
Thibault
T
Brohée
Dany
D
Babar
Sajida
S
Bouckaert
Vanessa
V
Simon
Anne-Catherine
AC
Toko
Jean-Pierre
JP
Walravens
Therese
T
Vincent
Jean-Louis
JL
Vanhaeverbeek
Michel
M
D000328:Adult; D000368:Aged; D002478:Cells, Cultured; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009439:Neuraminidase / Q000494:pharmacology*; D011446:Prospective Studies; D018805:Sepsis / Q000097:blood*
D009439:Neuraminidase