Microarray Analysis for Transcriptomic Profiling of Myocardium in Patients with Fatal Myocardial Infarction

Transcriptomic evidence from human myocardium in myocardial infarction (MI) is still not sufficient. Thus, there is a need for studies on human cardiac samples in relation to the clinical data of patients. The purpose of our pilot study was to investigate the transcriptomic profile of myocardium in the infarct zone, in comparison to the remote myocardium, in patients with fatal MI, via microarray analysis. This study included four patients with fatal MI type 1. We selected histologically verified samples from within the infarct area (n = 4) and remote myocardium (n = 4). The whole transcriptome was evaluated using microarray analysis. Differentially expressed genes (DEGs) clustered in the infarct area and in the remote myocardium allowed their differentiation. We identified a total of 1785 DEGs (8.32%) in the infarct area, including 1692 up-regulated (94.79%) and 93 down-regulated (5.21%) genes. The top 10 up-regulated genes were TRAIL, SUCLA2, NAE1, PDCL3, OSBPL5, FCGR2C, SELE, CEP63, ST3GAL3 and C4orf3. In the infarct area, we found up-regulation of seventeen apoptosis-related genes, eleven necroptosis-related, and six necrosis-related genes. Transcriptome profiling of the myocardium in patients with MI remains a relevant area of research for the formation of new scientific hypotheses and a potential way to increase the translational significance of studies into myocardial infarction.

Macrophages of the Cardiorenal Axis and Myocardial Infarction

The aim of our study was to compare the features of macrophage (mf) composition of the kidneys in patients with fatal myocardial infarction (MI) and in patients without cardiovascular diseases (CVD). We used kidney fragments taken during autopsy. Macrophage infiltration was assessed by immunohistochemistry: antibodies CD68 were used as a common mf marker, CD80-M1 type mf marker, CD163, CD206, and stabilin-1-M2 type. Macrophage composition of the kidneys in patients with fatal MI was characterized by the predominance of CD163+ cells among studied cells, and the control group was characterized by the predominance of CD163+, CD206+, and CD68+. In patients with MI, biphasic response from kidney cells was characterized for CD80+ and CD206+: their number decreased by the long-term period of MI; other cells did not show any dynamics. The exact number of CD80+ cells in kidneys of individuals without CVD was slightly higher than in patients with MI, and the number of CD206+-strikingly predominant. Subsequent analysis of CD80+ and CD206+ cells in a larger sample, as well as comparison of data with results obtained from survivors of MI, may bring us closer to understanding whether the influence on these cells can serve as a new target in personalized therapy in postinfarction complications.

Macrophages of the “Heart-Kidney” Axis: Their Dynamics and Correlations with Clinical Data and Outcomes in Patients with Myocardial Infarction

Changes in the macrophage infiltration of kidneys in rodents under ischemic conditions may affect cardiac macrophages and lead to development of adaptive cardiac remodeling. The aim of our study was to translate experimental findings into clinically relevant applications and assess the features of macrophage infiltration of the kidney and its correlations with changes in macrophage infiltration of the myocardium and with clinical data in patients who experienced a fatal myocardial infarction (MI). We examined fragments of both organs taken from patients (n = 30) who suffered from fatal MI. Macrophage infiltration was assessed by immunohistochemistry. Macrophage infiltration of the kidneys in patients with fatal MI is heterogeneous. The early period of MI was shown to be characterized by the prevalence of CD163+ and CD68+ cells, and in the long-term period by only CD163+ cells. However, only the level of CD206+ cells in the kidneys showed the dynamics representing the late MI period. Its decrease accompanied increase in the numbers of cardiac CD68+, CD163+, CD206+, and stabilin-1+ cells in the infarct area. Kidney CD206+ cells had more correlations with cardiac macrophages than other cells, and the presence of these cells also correlated with impairment of renal function and early death.

Stabilin-1+/SMA- macrophages in diagnostics of postinfarction tissue inflammation associated with adverse cardiac remodeling in patients with myocardial infarction

Introduction

Molecular biomarkers of monocytes/macrophages identified to date have provided advanced diagnostic capabilities. We have accumulated a large amount of knowledge related to the role of innate immune response in the development of postinfarction cardiac remodeling. However, there is no significant advancement in clinical studies.

Purpose

The purpose was to assess prospects of macrophage biomarkers in diagnostics of postinfarction tissue inflammation associated with adverse cardiac remodeling in patients with myocardial infarction (MI).

Methods

The study included 41 patients with MI type 1, died in 2013–2014. We used a biobank of tissue samples for analysis. Group 1 (n=24) comprised patients who died within 72 hours of MI (the inflammatory phase), group 2 (n=17) comprised patients who died 4–28 days after MI (the regenerative phase). Macrophage infiltration in the heart was assessed by double immunofluorescence. We used stabilin-1 as a marker of M2 macrophages, while α-smooth muscle actin (α-SMA) was considered as a marker of cell transdifferentiation. Cells were counted in the infarct (IA) and non-infarct area (NIA). Morphological determination of adverse cardiac remodeling was based on the ratio of heart size, in particular, length/width ratio that was <1.1.

Results

We identified subpopulations of stabilin-1+/α-SMA− and stabilin-1+/α-SMA+ macrophages. In the IA the number of stabilin-1+/α-SMA− macrophages was lower during the inflammatory phase than during the regenerative phase (Table 1). The calculation of sensitivity and specificity of stabilin-1+/α-SMA− macrophages in the NIA for predicting of adverse cardiac remodeling has shown following: AUC=0.96, p<0.001. The cut-off value was 18 cells/mm2. The ROC curve is presented in Figure 1.

Conclusions

We identified that number of stabilin-1+/α-SMA− macrophages in the NIA ranged from 0 to 18 cells/mm2 was associated with adverse cardiac remodeling. The presence of stabilin-1+/α-SMA+ macrophages could indicate persistent tissue inflammation and possibility of macrophage transdifferentiation and plasticity. Our study supports prospects for implementation of macrophage biomarkers in clinical practice that might become a breakthrough in the development of new methods for management of MI and following complications.

Figure 1

Funding Acknowledgement

Type of funding source: None

P6390Macrophages as contributors to chronic inflammation and cardiac fibrosis in patients with myocardial infarction

Introduction

The functional characteristics of tissue macrophages associated with the progression of cardiac fibrosis in clinic are still unknown.

Purpose

The purpose was to study cardiac macrophage phenotypes contributing to the development of chronic inflammation and fibrosis in patients with myocardial infarction (MI).

Methods

The study included 41 patients with fatal MI type 1. Group 1 (n=24) comprised patients who died within 72 hours of MI (the inflammatory phase) and group 2 (n=17) comprised patients who died 4–28 days after MI (the regenerative phase). Macrophage infiltration (number of cells) in the heart was assessed by double immunofluorescence in the non-infarct area. Each area was evaluated in 20 random fields. We used CD163, CD206, stabilin-1, α-smooth muscle actin (α-SMA), interleukin-10 (IL-10) as markers of M2-like macrophages.

Results

The number of CD163+/CD206− (p=0.087) and CD163+/206+ (p=0.072) macrophages was higher during the regenerative phase of MI. The number of CD163-/CD206+, stabilin-1+/α-SMA-, stabilin-1+/α-SMA+, stabilin-1+/IL-10−, stabilin-1+/IL-10+, stabilin-1-/IL-10+ did not significantly change throughout the entire period of MI. The comparison of various M2 macrophage subpopulations into groups revealed following. In group 1 the number of CD163+/CD206− and CD163+/CD206+ cells prevailed over CD163−/CD206+ (p=0.033 and p=0.003, respectively), stabilin1+/α-SMA− cells over stabilin-1+/α-SMA+ (p<0.001), and stabilin-1+/IL-10+ cells over stabilin-1+/IL-10− (p=0.018). In group 2 the quantity of stabilin-1+/α-SMA− macrophages prevailed over stabilin-1+/α-SMA+ (p=0.005) and stabilin-1+/IL-10+ over stabilin-1−/IL-10+ (p=0.028). In group 1 the number of CD163+/CD206+ cells correlated with the absolute and the relative number of peripheral blood monocytes prior to the onset of death (R=0.97), while the quantity of stablin-1+/α-SMA+ cells correlated with the absolute number of peripheral blood monocytes at admission (R=-0.53). In group 2 the quantity of CD206+/CD163− cells correlated with the absolute and the relative number of monocytes in the peripheral blood at admission (R=0.73 and R=0.59, respectively), the quantity of CD163+/CD206− macrophages with the incidence of recurrent MI (R= 0.54), and the number of stabilin-1+/α-SMA+ macrophages with the age of patients (R=-0.58).

Conclusions

We have suggested that the key cardiac macrophage phenotypes contributing to the development of chronic inflammation and cardiac fibrosis in the regenerative phase of MI were stabilin-1+/α-SMA− and stabilin-1+/IL-10+. We revealed subpopulation of stabilin-1+/α-SMA+ macrophages, that indicated the possibility of cellular transdifferentiation and macrophage plasticity. Thus, our results supports that understanding the role of macrophages in initiation, progression, and resolution of cardiac fibrosis is one of the most promising goal in the design of anti-fibrotic treatment strategies for patients with MI.

Cardiac CD68+ and stabilin-1+ macrophages in wound healing following myocardial infarction: From experiment to clinic

Myocardial infarction (MI) remains the leading cause of mortality and morbidity throughout the world. Macrophages are key innate immune cells that play a significant role in transition from the inflammatory to the regenerative phase during wound healing following MI. The scavenger receptor stabilin-1 is one of the most interesting macrophage biomarkers. This receptor contributes to wound healing, angiogenesis, and tissue remodeling. We suggested a research protocol using macrophage biomarkers to study the cellular basis of cardiac remodeling and healing in patients with acute MI. The purpose of the research was to translate experimental knowledge regarding macrophage subsets and their biomarkers in post-infarction myocardial regeneration into results observed in clinical settings. The study included 41 patients with fatal MI type 1. All patients were divided into four groups according to the timeline of MI histopathology. In addition to routine histopathological analysis, macrophage infiltration was assessed by immunohistochemistry. We used CD68 as a marker for the cells of the macrophage lineage and stabilin-1 as an M2-like macrophage biomarker. The number of CD68+ and stabilin-1+ macrophages in the infarct area increased and peaked in the regenerative phase and did not decrease in the late stage of MI. In the peri-infarct area, the number of CD68+ macrophages increased in the inflammatory phase, peaked during the reparative phase, and did not decrease in the late phase, while the number of stabilin-1+ macrophages increased in the regenerative phase and remained unchanged. Additionally, in the reparative phase, we observed increase in the number of CD68+ and stabilin-1+ macrophages in the non-infarct area. The research protocol suggested allowed us to translate experimental knowledge regarding macrophage subsets and their biomarkers in post-infarction myocardial regeneration into clinical data. Taken together, these results demonstrated biphasic cardiac macrophage response following acute MI somewhat similar to that in a murine model. The increase in stabilin-1+ macrophage infiltration noticed in the myocardium during the regenerative phase and the strong positive correlation between the number of these cells and timeline of MI histopathology enabled us to propose stabilin-1 as a diagnostic macrophage biomarker in myocardium wound healing in patients with acute MI.

Macrophage activation and polarization in post-infarction cardiac remodeling

Adverse cardiac remodeling leads to impaired ventricular function and heart failure, remaining a major cause of mortality and morbidity in patients with acute myocardial infarction. It have been shown that, even if all the recommended therapies for ST-segment elevation myocardial infarction are performed, one third of patients undergoes progressive cardiac remodeling that represents morphological basis for following heart failure. The need to extend our knowledge about factors leading to different clinical scenarios of myocardial infarction and following complications has resulted in a research of immuno-inflammatory pathways and molecular activities as the basis for post-infarction remodeling. Recently, macrophages (cells of the innate immune system) have become a subject of scientific interest under both normal and pathological conditions. Macrophages, besides their role in host protection and tissue homeostasis, play an important role in pathophysiological processes induced by myocardial infarction. In this article we summarize data about the function of monocytes and macrophages plasticity in myocardial infarction and outline potential role of these cells as effective targets to control processes of inflammation, cardiac remodeling and healing following acute coronary event.