Dose-dependent effects of intravenous allogeneic mesenchymal stem cells in the infarcted porcine heart.

Intravenous delivery of mesenchymal stem cells (MSCs) preserves myocardial function after infarction. This dose-escalating study was performed to examine pathologic remodeling and scar formation in a pig model of permanent coronary occlusion without restoration of reperfusion. MSCs labeled with fluorescent dye 48 h or saline (negative control, n = 8) were given intravenously 48 h post proximal left anterior descending artery occlusion. Animals received either autologous or allogeneic MSCs in doses from 1 x 10(3) up to 1 x 10(6) per kg bodyweight from an unrelated donor pig. Infarct size and myocardial function were assessed after 1 month. Morphologic analysis revealed that labeled autologous MSCs migrated in the peri-infarct region resulting in smaller infarct size (19 +/- 7% vs. 32 +/- 7%, p < 0.008) and higher fractional area shortening (33 +/- 7% vs. 21 +/- 3%, p < 0.001). Similarly, allogeneic MSCs had dose-dependent beneficial effects on cardiac function, statistically significant at 1 x 10(5) and 1 x 10(6) cells per kg bodyweight. Autologous as well as allogeneic MSCs specifically "home" to the heart after systemic delivery, leading to limited myocardial infarct size and improved functional outcome, even without coronary reperfusion. Therefore, intravenously administration of MSCs is an attractive minimal-invasive approach for cardiac tissue repair.

Regenerative capacity of intravenous autologous, allogeneic and human mesenchymal stem cells in the infarcted pig myocardium-complicated by myocardial tumor formation.

OBJECTIVES: Intravenous delivery of mesenchymal stem cells (MSCs) is an attractive approach for regeneration of infarcted myocardium. However, its efficacy is not well-defined in large animals. METHODS: Pigs (n =8) received intravenously autologous, allogeneic porcine or human MSCs (1 x 10(6) per kg bodyweight) labeled with fluorescent dye 48 hours post proximal LAD occlusion. Infarct size, histology and myocardial function were assessed 4 weeks later. RESULTS: Labeled MSCs migrated in the peri-infarct region resulting in improved myocardial function. Infarct size was larger in the control group (32+/-7%) compared to autologous (19+/-7%, p =0.008), allogeneic (24+/-4%, p =0.01) and human MSCs (26+/-5%, p =0.03). Fractional area shortening significantly increased after 4 weeks in pigs receiving autologous MSCs (34+/-7%, p =0.001), allogeneic MSCs (28+/-2%, p =0.004) and human MSCs (24+/-5%, p =0.027), but was lower in the control group (23+/-3%, n.s.). However, substantial callus formation and a non-malignant cardiac "tumor" containing mesenchymal tissue was observed in one animal treated with human MSCs. CONCLUSIONS: Intravenously administered MSCs prevent pathologic remodeling and scar formation but bare potential risks from inflammatory-related products.

Stem cell therapy improves myocardial perfusion and cardiac synchronicity: new application for echocardiography.

OBJECTIVES: Intravenous delivery of mesenchymal stem cell (MSC) is a noninvasive approach for myocardial tissue repair. We aimed to test this strategy in a pig model of myocardial infarction and to examine the usefulness of new echocardiographic applications to monitor cardioprotective effects of stem cell therapy. METHODS: Pigs (n = 8) received autologous or allogeneic MSCs (1 x 10(6)/kg body weight) labeled with fluorescent dye 48 hours after proximal left anterior descending coronary artery occlusion. Infarct size, myocardial function, and perfusion (A x beta) were assessed by myocardial contrast echocardiography and standard histologic methods after 1 month. RESULTS: Morphologic analysis revealed that labeled MSCs migrated in the peri-infarct region resulting in smaller infarct size by myocardial contrast echocardiography (control vs autologous and allogeneic MSC: 38 +/- 10% vs 25 +/- 5% and 28 +/- 6%, P < .01), higher fractional area shortening (23 +/- 3% vs 34.0 +/- 7% and 28 +/- 2%, P < .01), higher cardiac synchrony (167 +/- 36 vs 68 +/- 17 and 85 +/- 26 milliseconds, P < .003), and improved microvascular flow A x beta in the ischemic border zone (0.18 +/- 0.2 vs 0.56 +/- 0.3 and 0.49 +/- 0.2, P < .03). CONCLUSIONS: Systemic delivery of autologous and allogeneic MSCs preserves myocardial viability even in large animals and is, therefore, an attractive approach for tissue repair. Myocardial contrast echocardiography is useful to evaluate microvascular perfusion, which was enhanced by MSCs.

Intravenous delivery of autologous mesenchymal stem cells limits infarct size and improves left ventricular function in the infarcted porcine heart.

Systemic delivery of bone marrow-derived mesenchymal stem cells (MSCs) is a noninvasive approach for myocardial repair. We aimed to test this strategy in a pig model of myocardial infarction. Pigs (n = 8) received autologous MSCs (1 x 10(6)/kg body weight) labeled with fluorescent dye 48 h post proximal left anterior descending artery (LAD) occlusion. Hemodyamics, infarct size, and myocardial function were assessed at baseline and after 1 month. Morphologic analysis revealed that labeled MSCs migrated in the peri-infarct region, resulting in smaller infarct size (32 +/- 7 vs. 19 +/- 7%, p = 0.01), higher fractional area shortening (23 +/- 3 vs. 34.0 +/- 7%, p = 0.001), lower left ventricular end diastolic pressure (18.7 +/- 5 vs. 10.2 +/- 4 mmHg, p = 0.02) and higher +dp/dt (4,570 +/- 540 vs. 6,742 +/- 700 mmHg/s, p = 0.03) during inotropic stimulation. Systemic intravenous delivery of MSCs to pigs limits myocardial infarct size and is an attractive approach for tissue repair.