Bone Marrow-Derived Mesenchymal Stem Cells Have Innate Procoagulant Activity and Cause Microvascular Obstruction Following Intracoronary Delivery: Amelioration by Antithrombin Therapy

Abstract

Mesenchymal stem cells (MSCs) are currently under investigation as tools to preserve cardiac structure and function following acute myocardial infarction (AMI). However, concerns have emerged regarding safety of acute intracoronary (IC) MSC delivery. This study aimed to characterize innate prothrombotic activity of MSC and identify means of its mitigation toward safe and efficacious therapeutic IC MSC delivery post-AMI. Expression of the initiator of the coagulation cascade tissue factor (TF) on MSC was detected and quantified by immunofluorescence, FACS, and immunoblotting. MSC-derived TF antigen was catalytically active and capable of supporting thrombin generation in vitro. Addition of MSCs to whole citrated blood enhanced platelet thrombus deposition on collagen at arterial shear, an effect abolished by heparin coadministration. In a porcine AMI model, IC infusion of 25 3 10 6 MSC during reperfusion was associated with a decrease in coronary flow reserve but not when coadministered with an antithrombin agent (heparin). Heparin reduced MSC-associated thrombosis incorporating platelets and VWF within the microvasculature. Heparin-assisted therapeutic MSC delivery also reduced apoptosis in the infarct border zone at 24 hours, significantly improved infarct size, left ventricular (LV) ejection fraction, LV volumes, wall motion, and attenuated histologic evidence of scar formation at 6 weeks post-AMI. Heparin alone or heparin-assisted fibroblast control cell delivery had no such effect. Procoagulant TF activity of therapeutic MSCs is associated with reductions in myocardial perfusion when delivered IC may be successfully managed by heparin coadministration. This study highlights an important mechanistic insight into safety concerns associated with therapeutic IC MSC delivery for AMI. STEM CELLS 2015;33:2726-2737 SIGNIFICANCE STATEMENTStudies of mesenchymal stem cells (MSC) in chronic and acute myocardial ischemia suggest these cells are promising cell therapy candidates. However safety concerns remain especially with intracoronary delivery of therapeutic MSC, a route that would ideally expand the number of patients eligible for future treatment. We describe elevated prothrombotic TF expression in MSC, which is associated with in vitro and in vivo thrombosis and reductions in coronary flow reserve in the setting of acute MI therapy. We also describe an anti-thrombin therapeutic strategy that successfully negates these deleterious MSC effects while allowing safe and effective improvement in infarct size, regional and global LV functional parameters post MI. These data may have implications for risk assessment of patients enrolled in future acute myocardial infarction trials.

Homing and migration of mesenchymal stromal cells: How to improve the efficacy of cell therapy?

“…IA injection, which is already more risky because of the arterial puncture, also appears to entail a risk of development of microvascular occlusions called passive entrapment [27,46] . In addition, there have been reports that MSCs have a procoagulant activity [26,47] . A few years ago, a group from the Karolinska Institute reported that MSCs, particularly those that had been subjected to extended passaging and co-culture with activated lymphocytes, exhibited increased prothrombotic capacities; this effect was dose-dependent [47] .…”

“…A few years ago, a group from the Karolinska Institute reported that MSCs, particularly those that had been subjected to extended passaging and co-culture with activated lymphocytes, exhibited increased prothrombotic capacities; this effect was dose-dependent [47] . Gleeson et al [26] reported that MSCs express functionally active tissue factor. When MSCs were injected in the coronary arteries of a porcine myocardial infarction model, it resulted in a decreased coronary flow reserve.…”

“…When MSCs were injected in the coronary arteries of a porcine myocardial infarction model, it resulted in a decreased coronary flow reserve. This effect could be reversed by the co-administration of heparin, an antithrombin agent [26] . Kyriakou et al [48] have studied the factors influencing short-term bone marrow homing of MSCs.…”

“…Although IA injections might improve tissue-specific homing compared to IV, there is a concern that microthrombi might occur as a result of trapping large MSCs in the microvasculature. One example is the concern regarding IC injections of MSCs to treat myocardial infarction [26] . Similar concerns have been raised in studies that used MSCs to treat stroke [27,28] .…”

Retroperitoneal Hematoma after Bone Marrow Biopsy: The First Cut Should Not Be the Deepest

“…Fortunately, bleeding is rare, even with very low platelet counts. A possible explanation is that bone marrow mesenchymal cells express tissue factor besides other procoagulants [11]. The guideline for therapy with blood components issued by the German Federal Medical Association (Bundesärztekammer) advises against platelet transfusions before BMBs, which reflects their general perception as low-risk procedures [12].…”