Anti-inflammatory effects of clopidogrel intake in renal transplant patients: effects on platelet-leukocyte interactions, platelet CD40 ligand expression, and proinflammatory biomarkers.
BACKGROUND
Increased platelet activation has been described during treatment with various immunosuppressive agents and may contribute to the high cardiovascular mortality rate in renal transplant patients. Platelets are thought to propagate the inflammatory process of atherosclerosis by interaction with leukocytes.


METHODS
We tested an experimental therapy with clopidogrel in renal transplant patients treated with either tacrolimus (n = 20) or cyclosporine (INN, ciclosporin) (n = 19). All patients took low-dose steroids and had stable transplant function. Untreated healthy volunteers (n = 11) were included as the reference group. Degranulation (CD62P), glycoprotein IIb/IIIa receptor activation (PAC1), formation of platelet-leukocyte aggregates (monocyte-platelet-leukocyte aggregate, CD11b, mean fluorescence intensity), and platelet CD40 ligand (CD40L) expression (percent positive) were assessed by flow cytometry before therapy (visit 1) and after 4 weeks of clopidogrel (75 mg/d) intake (visit 2). To assess systemic anti-inflammatory effects, we measured levels of high-sensitivity C-reactive protein, soluble CD40L (sCD40L), monocyte chemoattractant protein 1, and matrix metalloproteinase 9 (MMP-9) by enzyme-linked immunosorbent assay.


RESULTS
At visit 1, cyclosporine-treated patients had significantly enhanced CD62P and PAC1 expression and platelet-leukocyte aggregate formation, as well as elevated sCD40L concentrations, compared with tacrolimus-treated patients (all P < .03). Clopidogrel intake led to a significant decrease in platelet-leukocyte aggregate formation in tacrolimus-treated patients (median, 237 [interquartile range, 177-510] to 194 [interquartile range, 159-275] mean fluorescence intensity; P < .035) and cyclosporine-treated patients (median, 450 [interquartile range, 362-782] to 254 [interquartile range, 211-458] mean fluorescence intensity; P < .035). CD40L expression was reduced in tacrolimus-treated patients (median, 34 [interquartile range, 28-41] to 21 [interquartile range, 12-26] mean fluorescence intensity; P < .002) and cyclosporine-treated patients (median, 33 [interquartile range, 30-37] to 26 [interquartile range, 19-26] mean fluorescence intensity; P < .02). In addition, CD62P, PAC1, and CD11b were significantly reduced in both groups at visit 2 (P < .02). MMP-9 decreased from 88 ng/mL (range, 49-135 ng/mL) to 57 ng/mL (range, 38-73 ng/mL) (P < .05) in tacrolimus-treated patients and from 79 ng/mL (range, 54-148 ng/mL) to 66 ng/mL (range, 41-97 ng/mL) (P < .01) in cyclosporine-treated patients. The sCD40L concentration decreased significantly only in cyclosporine-treated patients (P < .004). In contrast, high-sensitivity C-reactive protein and monocyte chemoattractant protein 1 were not affected.


CONCLUSIONS
The P2Y(12) receptor antagonist clopidogrel inhibits the expression of platelet activation markers and the interaction of platelets and leukocytes. Because the synthesis of vascular disease markers and inflammatory products such as sCD40L and MMP-9 has been inhibited, anti-inflammatory properties of clopidogrel are likely to be a result of decreasing platelet activation.
Graff
Jochen
J
pharmazentrum frankfurt, Institute of Clinical Pharmacology, University Hospital, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany. graff@em.uni-frankfurt.de
Harder
Sebastian
S
Wahl
Oliver
O
Scheuermann
Ernst-Heinrich
EH
Gossmann
Jan
J
D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents; D015415:Biomarkers; D001792:Blood Platelets / Q000187:drug effects*; D002097:C-Reactive Protein / Q000378:metabolism; D039481:CD11b Antigen / Q000097:blood; D019013:CD40 Antigens / Q000096:biosynthesis* / Q000097:blood; D018932:Chemokine CCL2 / Q000378:metabolism; D000077144:Clopidogrel; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood; D007249:Inflammation / Q000378:metabolism*; D016030:Kidney Transplantation / Q000502:physiology*; D007962:Leukocytes / Q000187:drug effects*; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D008875:Middle Aged; D009000:Monocytes / Q000187:drug effects; D015539:Platelet Activation / Q000187:drug effects; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D013988:Ticlopidine / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use
D000893:Anti-Inflammatory Agents; D015415:Biomarkers; C111835:CCL2 protein, human; D039481:CD11b Antigen; D019013:CD40 Antigens; D018932:Chemokine CCL2; D007166:Immunosuppressive Agents; D010975:Platelet Aggregation Inhibitors; D002097:C-Reactive Protein; D000077144:Clopidogrel; D020780:Matrix Metalloproteinase 9; D013988:Ticlopidine