Mg++: Médicament de la coagulopathie ?

Both acute delivery of and storage with magnesium sulfate promote cold-stored platelet aggregation and coagulation function

Meledeo MA et Al. J Trauma Acute Care Surg. 2015 Oct;79(4 Suppl 2):S139-45

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Il y a quelque mois était publié un travail de recherche portant sur  l'intérêt de l'administration de Adénosine/Lidocaïne/Mg2+ ALM (1, 2, 3). Une hypothèse faite par les auteurs  serait que L'ALM agirait comme un antifibrinolytique en activant la voie du thrombin-activatable fibrinolysis inhibitor (TAFI) plutôt que celle de la protéine C. Cette action passerait par un mécanisme antiinflammatoire, une modification de la polarité endothéliale et une action sur la fonction plaquettaire. Le travail expérimental dont l'abstract est présenté met en avant l'intérêt de l'adminsitration de magnésium pour la restauration de la fonction plaquettaire après conservation de palquettes d'aphérèse au delà de 5 jours.

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BACKGROUND:

The platelet storage lesion causes loss of function and viability over time. A new paradigm for platelet storage is desired to enable safer, more effective transfusions while reducing waste. We hypothesized that repletion of Mg, which is chelated by citrate anticoagulant, could reduce platelet storage lesion severity when given in conjunction with storage at a refrigerated temperature.

METHODS:

Apheresis platelet units were collected from healthy donors and stored at 22°C or 4°C. On Days 0, 2, 4, and 8, samples were collected for analyses of receptor-mediated aggregation, coagulation, adhesion to collagen under flow, and viability. In the first series, samples were given anacute dose of MgSO4 before testing; in the second series, storage bags were supplemented with 0-, 3-, or 6-mM MgSO4.

RESULTS:

Acutely delivered MgSO4 induced a more rapid coagulation time in apheresis platelets, further enhanced by storage at 4°C. Plateletadhesion to a collagen surface while exposed to arterial shear rates (920 s) was enhanced by MgSO4 supplementation-acute MgSO4 had a large effect on adhesion of fresh platelets, which diminished more rapidly in 22°C samples, while storage with MgSO4 showed significant benefits even out to Day 4 at both temperatures. Although 4°C storage improves the longevity of platelet aggregation responses to agonists, MgSO4 supplementation did not change those responses.

CONCLUSION:

Acute MgSO4 reduces clot time likely through the transient increase of free Ca. Limited differences between platelet function inacute delivery of and storage with MgSO4 diminish the possibility that Mg-induced metabolic inhibition of platelets synergizes with 4°C storage. Regardless, magnesium supplementation to platelets is an exciting possibility in transfusion because the adhesion response of 22°C-stored platelets on Day 4 is significantly enhanced when stored with 6-mM MgSO4