12th Congress of the European Hematology ... - Haematologica
12th Congress of the European Hematology ... - Haematologica
12th Congress of the European Hematology ... - Haematologica
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0844<br />
INCREASED LEUKOCYTE-PLATELET INTERACTIONS ASSOCIATED WITH HIGH RISK HEART<br />
SURGERY<br />
N.M. Matijevic, 1 A. Bracey, 2 B. Radovancevic, 2 R. Radovancevic, 2<br />
I. Gregoric, 2 O. Frazier 2<br />
1 University <strong>of</strong> Texas Health Science Cente, HOUSTON, TX; 2 Texas Heart<br />
Institute, HOUSTON, USA<br />
The role <strong>of</strong> circulating leukocytes and <strong>the</strong>ir interaction with platelets<br />
play an important role <strong>the</strong> hemostasis and inflammation. Leukocyteplatelet<br />
complex formation depends on <strong>the</strong> interaction between platelet<br />
P-selectin and leukocyte ligand P-selectin glycoprotein ligand-1 (PSGL-<br />
1). Implantation <strong>of</strong> a left ventricular assist device (LVAD) is used to provide<br />
hemodynamic support in patients with severe heart failure. Bleeding,<br />
thromboembolism, and infections are common complications associated<br />
with LVAD. Cell activation and leukocyte-platelet interactions<br />
during LVAD implantation is reported in a limited number <strong>of</strong> studies. We<br />
measured circulating levels <strong>of</strong> monocyte-platelet complexes (MPC), granulocyte-platelet<br />
complexes (GPC), and lymphocyte-platelet complexes<br />
(LPC) in 11 patients who received LVAD support. Blood samples were<br />
collected before LVAD implantation, and at days 3, 7, 14, 21, 30, 60, 90,<br />
and 180. Flow cytometry was used to measure circulating heterotypic<br />
cell aggregates. The following antibodies were used: CD14, CD162<br />
(PSGL-1), CD41(GPIIb), and CD62P (P-selectin). Monocytes were identified<br />
by specific staining with CD14 antibody, and lymphocytes and<br />
granulocytes were identified by <strong>the</strong>ir forward and side light scatter properties.<br />
The percentage <strong>of</strong> <strong>the</strong> leukocyte-platelet complexes was defined<br />
by <strong>the</strong>ir CD41 positivity. Baseline levels <strong>of</strong> PSGL-1 on monocytes were<br />
significantly higher than that on granulocytes and lymphocytes<br />
(160.6±21.5, 91.6±12.3, and 77.2±8.4), respectively. After transient<br />
increase on postoperative day 3, PSGL-1 surface expression showed persistent<br />
decreasing trends <strong>the</strong>reafter. The average percentages <strong>of</strong> <strong>the</strong> three<br />
types <strong>of</strong> leukocyte-platelet complexes were within normal range before<br />
implantation (9.1±2.5, 8.3±2.6, and 8.6±2.2, respectively). MPC and GPC<br />
increased significantly on day 7 (16.5±7.6 and 14.4±7.2), peaked on day<br />
21 (26.9±11.7 and 25.4±8.8), and remained significantly elevated up to<br />
60 days <strong>of</strong> <strong>the</strong> post implantation period. The average percentage <strong>of</strong> <strong>the</strong><br />
LPC increased by day 14 and remained elevated <strong>the</strong>reafter. A significant<br />
inverse correlation was found between MPC and monocyte PSGL-1 (R=-<br />
0.84), LPC and lymphocyte PSGL-1 (R=-0.78) and GPC and granulocyte<br />
PSGL-1 (R=-0.69), indicating increased levels <strong>of</strong> leukocyte and platelet<br />
activation. A significant positive correlation between MPC and CD14<br />
(R= 0.6), fur<strong>the</strong>r confirmed ongoing monocyte activation. The preliminary<br />
results <strong>of</strong> this pilot study documented an increased cellular activation<br />
and heterotypic cell interactions in patients undergoing high risk<br />
heart surgery. Circulating leukocyte-platelet complexes along with o<strong>the</strong>r<br />
markers <strong>of</strong> cell activation require correlation with longer follow-up <strong>of</strong><br />
larger groups <strong>of</strong> patients and subsequent clinical events in order to understand<br />
its clinical significance.<br />
0845<br />
TRANSFUSION RATES AND PLATELET ACTIVATION IN PATIENTS UNDERGOING HIGH RISK<br />
CARDIAC SURGERY<br />
A. Bracey, 1 R. Radovancevic, 1 N. Matijevic, 2 B. Radovancevic, 1<br />
S. Carranza, 1 I. Gregoric, 1 O. Frazier1 1 2 Texas Heart Institute, HOUSTON; Univesity <strong>of</strong> Texas Health Science Center,<br />
HOUSTON, USA<br />
Introduction. Left ventricular assist device (LVAD) implantation is associated<br />
with a high incidence <strong>of</strong> hemorrhagic complications, high-volume<br />
transfusion and reexploration rates for bleeding. Increased platelet<br />
activation in <strong>the</strong>se patients is reported in a limited number <strong>of</strong> studies. We<br />
sought to determine <strong>the</strong> effect <strong>of</strong> preoperative platelet activation on<br />
bleeding and transfusion rates in this surgical procedure. Methods. We<br />
used flow cytometry methods to measure expression <strong>of</strong> <strong>the</strong> platelet activation<br />
markers in 11 patients (7 men, 4 women) with end stage heart failure<br />
who underwent LVAD implantation. P selectin (CD62P) and thrombospondin<br />
(TSP) levels were analyzed and compared to transfusion rates<br />
and bleeding. Data collected include: age, body weight, sex, intraaortic<br />
balloon pump insertion, previous cardiac surgery, creatinine, BUN, total<br />
bilirubin, and hemoglobin levels, PT, INR, PTT, platelet count, WBC<br />
count, and antifibrinolytic use. Results. Preoperatively, <strong>the</strong> average percentage<br />
<strong>of</strong> positive platelets was 26±13% for CD62P and 9.4±5.4% for<br />
TSP. Six patients with percent <strong>of</strong> positive platelets equal or greater than<br />
<strong>the</strong> median value for CD62P (23.7%) and TSP (9.5%) required more<br />
platelet transfusions (9.2±3.1 vs. 3.8± 2.9 units, p=0.015) and bled more<br />
12 th <strong>Congress</strong> <strong>of</strong> <strong>the</strong> <strong>European</strong> <strong>Hematology</strong> Association<br />
(74±23 vs. 43±26 mL/kg, p=0.037). They also required more red blood<br />
cell units (11.3±4.4 vs. 6.8±3.9, p=0.052) and fresh frozen plasma units<br />
(14.7±5.6 vs. 6.2±4.1, p=0.035) than patients who had less activated<br />
platelets. Conclusions. These results on a limited number <strong>of</strong> patients suggest<br />
correlation <strong>of</strong> platelet activation with increased bleeding and transfusion<br />
requirements during LVAD implantation. Fur<strong>the</strong>r study is warranted<br />
to confirm this finding.<br />
0846<br />
IMMUNE CELLS MIMIC THE MORPHOLOGY OF ENDOTHELIAL PROGENITOR COLONIES IN<br />
VITRO<br />
E. Rohde, 1 C. Bartmann, 2 K. Schallmoser, 1 A. Reinisch, 3 G. Lanzer, 1<br />
W. Linkesch, 3 C. Guelly, 4 D. Strunk3 1 Div. <strong>of</strong> Transfusion Medicine, GRAZ; 2 Div. <strong>of</strong> <strong>Hematology</strong>; Transfusion Medicine,<br />
GRAZ; 3 Div. <strong>of</strong> Hemetology, GRAZ; 4 Center for Medical Research, GRAZ,<br />
Austria<br />
Background. Endo<strong>the</strong>lial progenitor cells (EPC) are considered powerful<br />
biologic markers for vascular function and cardiovascular risk predicting<br />
events and death from cardiovascular causes. Colony-forming units<br />
<strong>of</strong> endo<strong>the</strong>lial progenitor cells (CFU-EC) are used to quantify EPC circulating<br />
in human peripheral blood. The mechanisms underlying colony<br />
formation and <strong>the</strong> nature <strong>of</strong> <strong>the</strong> contributing cells are not clear. Methods.<br />
We performed subtractive CFU-EC analyses to determine <strong>the</strong> impact <strong>of</strong><br />
various blood cell types and kinetics <strong>of</strong> protein and gene expression during<br />
colony formation. Results. We found that CFU-EC mainly comprise<br />
T cells and monocytes admixed with B cells and NK cells. The combination<br />
<strong>of</strong> purified T cells and monocytes formed CFU-EC structures.<br />
The lack <strong>of</strong> colonies after depletion or functional ablation <strong>of</strong> T cells or<br />
monocytes was contrasted with effective CFU-EC formation in <strong>the</strong><br />
absence <strong>of</strong> CD34 + cells. Microarray analyses revealed activation <strong>of</strong><br />
immune function-related biological processes without changes in angiogenesis-related<br />
processes during colony formation. In concordance with<br />
a regenerative function, soluble factors derived from CFU-EC cultures<br />
supported vascular network formation in vitro. Conclusions. Recognizing<br />
CFU-EC formation as <strong>the</strong> result <strong>of</strong> a functional cross between T cells and<br />
monocytes shifts expectations <strong>of</strong> vascular regenerative medicine. Our<br />
data support <strong>the</strong> move from a view <strong>of</strong> circulating EPC towards models<br />
that include a role for immune cells in vascular regeneration.<br />
0847<br />
EVALUATION OF RELEASED FACTORS, WITH A POTENTIAL POST-TRANSFUSION<br />
IMMUNOMODULATORY ROLE, DURING THE STORAGE OF PLATELET CONCENTRATES<br />
S. Misso, 1 L. Paesano, 2 M. D'On<strong>of</strong>rio, 2 B. Feola, 1 C. Marotta, 1<br />
G. Fratellanza3 , E. D'Agostino3 , A. Minerva1 1 Hospital S. Sebastiano and S. Anna, CASERTA; 2 Hospital S. Giovanni Bosco,<br />
NAPLES; 3 University Federico II, NAPLES, Italy<br />
Background. Platelets have a specialized role in haemostatic responses,<br />
in spite <strong>of</strong> this, new functions have been recently identified. In fact,<br />
<strong>the</strong> thrombocytes also participate in <strong>the</strong> process <strong>of</strong> inflammation by<br />
releasing different substances capable <strong>of</strong> modulating <strong>the</strong> whole inflammatory<br />
response by interactions with both endo<strong>the</strong>lial and white blood<br />
cells. Recent studies have demonstrated that <strong>the</strong> platelets take part in<br />
immunity and inflammation mainly by means <strong>of</strong> <strong>the</strong> CD40/CD40L<br />
pathway. Aims. Our objective has been to evaluate <strong>the</strong> accumulation <strong>of</strong><br />
cytokines, during <strong>the</strong> storage, in platelet concentrates obtained from<br />
platelet-rich plasma. Methods. Fifty platelet concentrates have been analyzed<br />
in Caserta’s Hospital; a plasma sample has been taken from every<br />
unit just after production <strong>of</strong> <strong>the</strong> hemocomponent (T.0) and after 1 (T.1),<br />
3 (T.3), and 5 (T.5) days <strong>of</strong> storage (at 22±2°C in continuous agitation).<br />
IL-6, IL-8, PDGF-AA, sCD40L and leptin levels have been assayed by<br />
specific ELISA commercial kits (R&D Systems). Results. IL-6 (T.0= 6.3±1.9<br />
pg/mL, T.1=7.1±2.6, T.3=9.3±3.1, T.5=10.2±3.9, p>0.05) and IL-8<br />
(T.0=8.9±3.3 pg/mL, T.1=10.1±3.6, T.3=12.3±4.1, T.5=16.8±6.4, p>0.05)<br />
levels have been stable during all <strong>the</strong> storage with no statistical significant<br />
variation. On <strong>the</strong> o<strong>the</strong>r hand, PDGF-AA (T.0=210±20 pg/mL,<br />
T.1=298±36, T.3=463±29, T.5=690±47, p