CD271+ Human Mesenchymal Stem Cells Show Antiarrhythmic Effects in a Novel Murine Infarction Model

Abstract

Background: Ventricular arrhythmias (VA) are a common cause of sudden death after myocardial infarction (MI). Therefore, developing new therapeutic methods for the prevention and treatment of VA is of prime importance.

Methods: Human bone marrow derived CD271⁺ mesenchymal stem cells (MSC) were tested for their antiarrhythmic effect. This was done through the development of a novel mouse model using an immunocompromised Rag2^-/- γc^-/- mouse strain subjected to myocardial "infarction-reinfarction". The mice underwent a first ischemia-reperfusion through the left anterior descending (LAD) artery closure for 45 minutes with a subsequent second permanent LAD ligation after seven days from the first infarct.

Results: This mouse model induced various types of VA detected with continuous electrocardiogram (ECG) monitoring via implanted telemetry device. The immediate intramyocardial delivery of CD271⁺ MSC after the first MI significantly reduced VA induced after the second MI.

Conclusions: In addition to the clinical relevance, more closely reflecting patients who suffer from severe ischemic heart disease and related arrhythmias, our new mouse model bearing reinfarction warrants the time required for stem cell engraftment and for the first time enables us to analyze and verify significant antiarrhythmic effects of human CD271⁺ stem cells in vivo.

Keywords: arrhythmia; cardiac regeneration; electrocardiography; stem cells.

Figure 1

Induction of ventricular arrhythmias (VA). Schematic drawing of the loose left anterior descending (LAD) ligature positioning (A). Mouse ECG changes in relation to the time of the firs LAD ligation during ischemia-reperfusion infarction (B). Mouse ECG changes in relation to the time of the permanent second LAD-ligation (reinfarction and URI group C). Mouse ECG strips showing different types of observed VA (D).

Figure 2

Flow cytometric analysis of MACS-isolated human BM CD271⁺ stem cells. The freshly isolated BM derived CD271⁺ stem cells showed a mesenchymal identity by a predominant expression of CD73 and CD105 MSC markers as compared with the entire MNC fraction. Mean ± SD, * p ≤ 0.015 (Mann–Whitney U Test).

Figure 3

Comparison of developed VA. Until 12 h post LAD ligation (A,B). At the time period 45 min to 12 h post the second LAD ligation (C). ECG monitoring immediately prior to the second LAD ligation (D). QRS duration and QTc-interval 48 h post the first infarction and immediately prior to the second intervention (E,F). Mean ± SD, * p ≤ 0.05 as compared with MIC, ^# p ≤ 0.05 as compared with SRI (Mann–Whitney U Test). Representative images illustrate the engrafted human stem cells 9 days post transplantation performed for the SRI experimental group which the remaining human MSC were found predominantly in the peri-infarct area as with the Fast Green and Sirius Red staining method (the left picture) confirmed (G).

Figure 4

Alterations in MI size. Representative images show the infarction area (enclosed within the yellow border) for URI, SRI, and MIC 9 days after the first LAD ligation (Fast Green and Sirius Red staining) (A), as well as 48 h after the second LAD ligation (Hematoxylin and Eosin staining) (B). Significant increase of the infarction size after the second LAD ligation, mean ± SD, * p ≤ 0.009 as compared with the first LAD ligation, ^# p ≤ 0.041 in contrast to MIC (Mann–Whitney U test) (C).