Clinical implications of NETs in patients with ischemic stroke: thrombi and plasma analysis from patients treated with mechanical thrombectomy

Abstract

Background: Stroke is the first cause of disability and it has been one of the two leading causes of death in the world during the last 15 years, affecting around 120,000 deaths in Spain and 17,000 in Catalonia. A third of ischaemic strokes are classified as cryptogenic (unknown cause) after an extensive and multidirectional etiological study. Not having a well-known cause of the primary stroke makes difficult to approach an effective secondary prevention in order to avoid recurrences. The histopathologic analysis of thrombi in patients with acute ischaemic stroke (AIS) has revealed differences between patients but no conclusive information has been found yet. Neutrophils and neutrophil extracellular traps (NETs) seems to contribute to thrombus formation and resistance to reperfusion therapy showing different concentrations depending on the underlying physiopathological mechanism. Histologic features of thrombi may provide some clues to stroke etiology, which is helpful for determining the strategy of stroke prevention. Research on thrombus may also be helpful for improving reperfusion therapy being a new target. Objectives: The aim of this study is to provide more information about the relationship

between NETs content in thrombi of patient with AIS and its etiology according to the SSS- TOAST Classification and to assess the association between the composition in NETs of

thrombi and the concentration of surrogate markers of NETs in peripheral blood. Design: The study will be an observational, analytic and transversal study. Two hospitals will take part in this study: Hospital Universitario Doce de Octubre (12O) de Madrid and Hospital Universitari Doctor Josep Trueta (HDJT) de Girona as the coordinator centre. Participants: Patients ≥ 18 years with AIS who have required an endovascular treatment from which it has been possible to successfully extract the thrombus. Methods: Thrombi retrieved from ischaemic stroke patients undergoing endovascular treatment will be analysed by immunostaining using neutrophil markers (CD66b) an NET markers (citrullinated Histone H3 [H3Cit] and extracellular DNA). Neutrophils and NETs will be quantified. Also, plasma extracted will be analysed using ELISA to determine surrogate markers of NETs in peripheral blood (cfDNA and H3Cit)