Granulocyte- and monocyte-platelet adhesion index in coronary and peripheral blood after extracorporeal circulation and reperfusion.
BACKGROUND
Neutrophil-granulocyte and mononuclear-cell functional changes occur during cardiopulmonary bypass and cardiovascular surgery. In particular, leukocyte-platelet interaction, leading to generation of heterotypic coaggregates, represents an amplification mechanism of the local inflammatory response and tissue damage.


METHODS
Samples of 20 patients were drawn from venous coronary sinus before cardioplegic arrest and immediately after reperfusion, as well as from peripheral blood at 5 and 24 h postoperatively. The granulocyte and monocyte surface expression of CD162, CD15s, CD18, and CD11b were quantified by flow cytometry at the different times. Parallel variations of circulating leukocyte-platelet conjugates (percentages) and a derived (cell number-normalized) leukocyte-platelet adhesion index were measured using a combination of antibodies against CD45, CD14, and CD41a. The evaluation of platelet functional state was carried out using antibodies against CD62P (P-selectin) and PAC-1.


RESULTS
Monocyte and granulocyte cell number increased markedly in coronary blood at reperfusion and in peripheral blood postoperatively when compared with measurements done before cardioplegia. A very different course characterized the changes of the leukocyte-platelet adhesion index with respect to the variations of circulating leukocyte-platelet coaggregates (percentages). Leukocyte molecules expression showed no significant variations for CD15s on both the leukocyte subsets, while a significant up-modulation for CD162 was observed on monocytes at 24 h after extracorporeal circulation (P = 0.0002), and for CD11b on granulocytes at 5 h postoperatively (P = 0.033). A loss of CD162 expression was observed in coronary blood at reperfusion (P = 0.0038) on granulocytes, associated to a down-modulation of CD18 (P = 0.0033) and CD11b (P = 0.0184) in peripheral blood at 24 h postoperatively. No significant up-regulation of platelet activatory molecules expression was found at coronary reperfusion, as well as postoperatively in the peripheral blood, when compared with the before-cardioplegia derived data.


CONCLUSIONS
The over time variations of a normalized leukocyte-platelet adhesion index seem to reflect the cumulative leukocyte-platelet functional interaction more accurately than the parallel measurements of cellular conjugates. The absence of platelet activation suggests that the leukocyte membrane modifications play a main role in controlling the formation and stability of heterotypic leukocyte-platelet coaggregates after cardiac surgery with extracorporeal circulation.
Sbrana
Silverio
S
Laboratory of Hematology and Flow Cytometry, CNR Institute of Clinical Physiology, Massa, Italy. sbrana@ifc.cnr.it
Buffa
Manuela
M
Bevilacqua
Stefano
S
Spiller
Dario
D
Parri
Maria Serena
MS
Gianetti
Jacopo
J
De Filippis
Rossella
R
Clerico
Aldo
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001769:Blood; D001804:Blood Transfusion, Autologous; D002448:Cell Adhesion; D003331:Coronary Vessels / Q000166:cytology*; D005112:Extracorporeal Circulation; D005260:Female; D006098:Granulocytes / Q000502:physiology*; D006324:Heart Arrest, Induced; D006801:Humans; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000502:physiology*; D015425:Myocardial Reperfusion; D010973:Platelet Adhesiveness; D013997:Time Factors