Immature neutrophil is associated with coronary plaque vulnerability based on optical coherence tomography analysis

INTRODUCTION

High neutrophil to lymphocyte ratio is considered to predict poor prognosis of acute coronary syndrome (ACS). However, the association of neutrophil subpopulation with plaque vulnerability and the incidence of ACS remains unknown.

METHODS AND RESULTS

Blood samples from 48 patients with unstable angina (UA), 31 with ST-segment elevation myocardial infarction (STEMI) and 33 healthy controls were collected at admission. The morphology of coronary plaques in 48 UA patients were further evaluated by optical coherence tomography (OCT). According to maturation stages of neutrophils and the expression of CD10 and CD101, circulating neutrophils could be divided into pre-neutrophils (CD101-CD10-), immature neutrophils (CD101+CD10-) and mature neutrophils (CD101+CD10+). While the number of pre-neutrophil was quite low in blood and comparable among three groups, the absolute counts and percentage of CD10- immature neutrophils were higher in peripheral bloods of UA and STEMI patients compared with those in healthy controls. The concentration of plasma myeloperoxidase was positively associated with the percentage of CD10- immature neutrophils. Furthermore, UA patients with thin-cap fibroatheroma (TCFA) observed by OCT had a higher proportion and larger number of immature neutrophils as compared to those without TCFA. The percentage of immature neutrophils also closely correlated with plaque rupture and the feature of vulnerable plaque, including thinner fibrous cap and larger lipid core, but did not associate with percent lumen stenosis.

CONCLUSION

Our findings emphasize that the abnormally increased level of CD10- immature neutrophils may sever as a promising marker of the incidence of ACS and plaque vulnerability.

Age is the work of art? Impact of neutrophil and organism age on neutrophil extracellular trap formation

Neutrophil extracellular traps or NETs are released by highly activated neutrophils in response to infectious agents, sterile inflammation, autoimmune stimuli and cancer. In the cells, the nuclear envelop disintegrates and decondensation of chromatin occurs that depends on peptidylarginine deiminase 4 (PAD4) and neutrophil elastase (NE). Subsequently, proteins from neutrophil granules (e.g., NE, lactoferrin and myeloperoxidase) and the nucleus (histones) bind to decondensed DNA and the whole structure is ejected from the cell. The DNA decorated with potent antimicrobials and proteases can act to contain dissemination of infection and in sterile inflammation NETs were shown to degrade cytokines and chemokines via serine proteases. On the other hand, overproduction of NETs, or their inadequate removal and prolonged presence in vasculature or tissues, can lead to bystander damage or even initiation of diseases. Considering the pros and cons of NET formation, it is of relevance if the stage of neutrophil maturation (immature, mature and senescent cells) affects the capacity to produce NETs as the cells of different age-related phenotypes dominate in given (pathological) conditions. Moreover, the immune system of neonates and elderly individuals is weaker than in adulthood. Is the same pattern followed when it comes to NETs? The overall importance of individual and neutrophil age on the capacity to release NETs is reviewed in detail and the significance of these facts is discussed.