Circulating Monocyte Subsets Are Associated With Extent of Myocardial Injury but Not With Type of Myocardial Infarction.

Noushin Askari,Dimitri Grün,Christoph Lipps,Beatrice Von Jeinsen,Christoph Liebetrau,Sandra Voss,Roland Klingenberg,Oliver Dörr,Nora Staubach,Holger Nef,Jan Sebastian Wolter,Steffen Kriechbaum,Christian W Hamm,Till Keller

doi:10.3389/fcvm.2021.741890

Abstract

Inflammation is a hallmark of the period after a myocardial infarction (MI) that is either promoted or resolved by distinct subtypes of circulating inflammatory cells. The three main monocyte subpopulations play different roles inflammation. This study examined whether the type of MI (type 1 or type 2) or the extent of myocardial injury is associated with differences in monocyte subpopulations. For this purpose, peripheral whole blood from patients with a suspected MI was used for flow cytometric measurements of the monocyte subpopulations, and myocardial injury was classified by cardiac troponin levels in serum. In patients with acute coronary syndrome (n = 82, 62.2% male) similar proportions of the monocyte subsets were associated with the two types of MI, whereas total monocyte counts were increased in patients with substantial myocardial injury vs. those with minor injury (p = 0.045). This was accompanied by a higher proportion of intermediate (p = 0.045) and classical monocytes (p = 0.059); no difference was found for non-classical monocytes (p = 0.772). In patients with chronic coronary syndrome (n = 144, 66.5% male), an independent association with myocardial injury was also observed for classical monocytes (p = 0.01) and intermediate monocytes (p = 0.08). In conclusion, changes in monocyte subpopulation counts, particularly for classical and intermediate monocytes, were related to the extent of myocardial injury in acute and stable coronary artery disease but not to the type of MI.

Highlights

Myocardial infarction (MI) is one of the most frequent cardiovascular events and leads to relevant morbidity and mortality
It has been suggested that the proportion of the three subpopulations of monocytes can differ with the presence of disease, such as the different characteristics associated with different types of MI [8]
MI patients were further classified according to the final diagnosis of MI type: MI type 1, the prototypical acute MI (T1MI, n = 52, 73% male, age: 59–78 years) or MI type 2, an MI based on ischemia due to an oxygen demand/supply mismatch (T2MI, n = 10, 50% male, age: 61–81 years)

Summary

Introduction

Myocardial infarction (MI) is one of the most frequent cardiovascular events and leads to relevant morbidity and mortality. Monocytes represent ∼5% of peripheral blood leucocytes; they constitute an essential component of the immune system linking innate and adaptive immunity and are critical drivers in many inflammatory processes [3]. This is the case in atherosclerosis, in which monocytosis after an MI is associated with impaired recovery and unfavorable prognosis of atherosclerotic disease [4, 5]. Monocytes are divided into classical monocytes (CD14++CD16–), representing up to 90% of the blood monocytes, intermediate monocytes (CD14++CD16+), and non-classical monocytes (CD14+CD16++) [6] These three monocyte subsets have distinct phenotypic and functional characteristics and play different roles in inflammation and malignancy. It has been suggested that the proportion of the three subpopulations of monocytes can differ with the presence of disease, such as the different characteristics associated with different types of MI [8]

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