Ο ρόλος των ουδετερόφιλων στην θρόμβωση

Δημήτριος Στάκος, FESC, FSCAIΕπ. καθηγητής ΚαρδιολογίαςΔ.Π.Θ. Αλεξανδρούπολη

Αιμόσταση vs θρόμβωση

Αγγειακός ιστικός παράγοντας (TF) και blood-born TF

Αιμόσταση vs θρόμβωση

Η συμμετοχή ανοσιακών διαδικασιών βασική διαφορά μεταξύ αιμόστασης - θρόμβωσης

Ποια είναι η σημασία των κυττάρων της φυσικής ανοσίας στη θρόμβωση ?

Pawlinski R, et al. Blood, 2010

Control mice transplanted with low-hTF bone marrow cells

Hematopoietic TF, but not vessel wall TF is responsible for initiation of DVT

ctrl ctrl +BM

(low TF)

Neutropenic mice and thrombus size

* Ab to deplete neutrophils

anti-Ly6G antibody*

*

von Brühl, et al. J Exp Med. 2012

How innate immune cells initiate DVT development ? The significance of TF

Furie B. J Thromb. Haemost. 2007Manly DA. Annu. Rev. Physiol 2011

Fibrin formation

ctrl

ctrl

What signals supporting thrombogenesis are delivered by neutrophils?

Darbousset R, et al. Blood 2012

PMNs expressing TF is the main source of TF needed for platelet thrombus formation and fibrin generation following a laser-induced injury in vivo.

Encrypted TF

Brinkmann V, et al. Neutrophil extracellular traps kill bacteria. Science 2004

Neutrophil-derived structures composed of extruded DNA, decorated with antimicrobial proteins

NET’s function

High local concentration of antimicrobial components

Kill microbes extracellularly independent of phagocytic uptake

Physical barrier that prevents further spread of the pathogens

Delivery of granule proteins into NETs (keep injurious proteins - proteases from diffusing)

Less energy consuming

PMN

Pathogen

NET formation

Firm attachment to the substratum

Disintegration of membranes - mixture

Cell contraction –membrane rupture

Brinkmann V. J Cell Biol. 2012

Our hypothesis

Normal artery

of the same patient

Culprit lesion in Lcx

(STEMI)

NETS in STEMI

MP

O/D

NA

co

mp

lex

ELIS

A

Στην ένοχη αρτηρία υπάρχει σημαντική απελευθέρωση ΝΕΤs (τοπικά)

Έκφραση ιστικού παράγοντα στα STEMI NETs

Παραγωγή θρομβίνης (ενεργότητα TF)

Ο ιστικός παράγοντας στα NETs είναι ενεργός και η ενεργότητα του εξαρτάται από το ΝΕΤ

Ενεργοποίηση αιμοπεταλίων (ενεργότητα TF)

Ο ιστικός παράγοντας στα NETs είναι ενεργός και η ενεργότητα του εξαρτάται από το ΝΕΤ

ΝΕΤs με ιστικό παράγοντα μέσα στο θρόμβο

Intracellular TF upregulation in circulatinh PMNs of STEMIC

ircu

lati

ng

PM

Ns

STEM

I

TF mRNA (PCR)

Western

1st stimulus intracellular TF upregulation (systemic)

2nd stimulus (highly local) release of NETs expressing TF thrombosis

A mechanism for TF-bearing NET release in STEMI

A substance in STEMI plasma (inflammatory) is responsible for the 1st hit

NETs in arterial thrombosis

Platelet aggregation (RED)

Activated platelets induce the formation of NETs not expressing TF in the absence of the 1st hit (STEMI plasma)

In vitro reproduction of double hit phenomenon

IRA-derived platelets

Conclusions

1. Abundant NET release in IRA of STEMI patients

2. Local phenomenon

3. Functional TF is expressed on NETs able to induce thrombin generation and PLT activation into thrombus

4. Thrombin-activated platelets induce more NET release in a vicious cycle

5. NET (DNA) scaffold in imperative for TF functionality

6. TF-bearing NET release is a double-hit mechanism

initial intracellular TF upregulation is followed by TF-bearing NET release

7. DNase treatment may potentiated the effects of current antithrombotic treatment

8. NETs may represent another mechanism that link thrombosis-inflammation and innate immunity

Do PMNs regulate the delivery of intracellular substances on their NETs depending on the circumstances?

PMNs

NETs decorated with anti-microbial enzymes (NE, MPO)

NETosis

Pathogen invasion

Elimination

Sterile inflammation

NETs decorated with prothrombotic material (TF) Thrombosis

INFLAMMATION

Thrombosis

NETs exposing TF

Intracellular TF

TF gene

NETs as a possible link between innate immunity and Thrombosis

Microcirculation

Platelets

PMNs

Sterile

Ruptured atherosclerotic plaque

Pathogen invasion

Vascular wall

Vasculitis

Microcirculation

DVT/arterial thrombosis/STEMI

NETosis

Sepsis

Large vessels

Thrombosis

Sh2-199, Soul NebulaIC 1848. NASA

Baboon DVT Immunostaining DNA/Histone and VWF

Baboon DVTStaining for extracellular DNA

NGC 6334 "Cat's Paw Nebula", Scorpius Constellation - NASA