Cardiac Stem Cell Transplantation Research Articles

Cardiac safe hematopoietic stem cell transplantation protocol for systemic sclerosis with myocarditis- a two-step approach.

Cardiac safe hematopoietic stem cell transplantation protocol for systemic sclerosis with myocarditis- a two-step approach.

Cardiac and autologous stem cell transplantation hematopoietic in patients with AL amyloidosis

Cardiac and autologous stem cell transplantation hematopoietic in patients with AL amyloidosis

Total Lymphatic Irradiation as Part of Conditioning in Pediatric Hematopoietic Stem Cell Transplantation: A Single Institution Experience From a Radiation Oncology Perspective

Purpose/Objective(s)Total lymphatic irradiation (TLI) is a procedure in which a patient's major lymph nodes and spleen are treated with low doses of radiation for recipient immunosuppression as part of multi-agent conditioning for cardiac, lung or hematopoietic stem cell transplantation, to facilitate engraftment and to decrease the risk of rejection. TLI is considered an attractive option instead of total body irradiation (TBI) to mitigate side effects of radiation exposure to normal tissues. There are no established guidelines on technique and dose fractionation. Herein, we share our experience.Materials/MethodsRetrospective review of children who received TLI for hematopoietic stem cell transplants at the hospital was done.ResultsTwenty-two patients who had TLI from 2004 to 2020, with a median age of 7.5 years (range 0.9-19.0) were included. Twelve had benign conditions and 10 had malignant conditions. Eighteen had haploidentical grafts, 2 had matched sibling and 2 had unrelated donors. Four patients had previously failed engraftment prior to TLI. Conditioning included multi-agent chemotherapy for all including rabbit-ATG for 12 patients. All patients had computer-tomographic scans simulation except for 2 patients who were treated in the earlier years when only orthogonal XR was available. Dose fractionation was single prior to 2017 (5-7Gy/1#) and in recent times more fractionated (6-7.5Gy/3#). The treatment targets were the spleen and the following nodal stations: cervical, axillary, mediastinal, hilar, paraaortic, pelvic, inguinal and femoral. Normal organs including the medial thyroid, heart, lungs, and abdominal organs were shielded with multi-leaf collimators using three-dimensional conformal technique (Figure 1, 2). Of 12 patients with benign conditions, all are alive at last follow up. Of 10 patients with malignant conditions, 3 are dead from disease. Five out of 12 patients who had haploidentical grafts, 0/2 matched sibling graft and 1/2 unrelated grafts experienced rejection. The median follow up is 14.0 months (IQR 6-41.5). None developed acute pneumonitis. One patient developed thyroid cancer 14 years after TLI.ConclusionHerein we describe our TLI experience and technique. More studies should be undertaken to evaluate the safety and efficacy of TLI compared to TBI. Going forward, a consensus on technique and dose should be developed. Total lymphatic irradiation (TLI) is a procedure in which a patient's major lymph nodes and spleen are treated with low doses of radiation for recipient immunosuppression as part of multi-agent conditioning for cardiac, lung or hematopoietic stem cell transplantation, to facilitate engraftment and to decrease the risk of rejection. TLI is considered an attractive option instead of total body irradiation (TBI) to mitigate side effects of radiation exposure to normal tissues. There are no established guidelines on technique and dose fractionation. Herein, we share our experience. Retrospective review of children who received TLI for hematopoietic stem cell transplants at the hospital was done. Twenty-two patients who had TLI from 2004 to 2020, with a median age of 7.5 years (range 0.9-19.0) were included. Twelve had benign conditions and 10 had malignant conditions. Eighteen had haploidentical grafts, 2 had matched sibling and 2 had unrelated donors. Four patients had previously failed engraftment prior to TLI. Conditioning included multi-agent chemotherapy for all including rabbit-ATG for 12 patients. All patients had computer-tomographic scans simulation except for 2 patients who were treated in the earlier years when only orthogonal XR was available. Dose fractionation was single prior to 2017 (5-7Gy/1#) and in recent times more fractionated (6-7.5Gy/3#). The treatment targets were the spleen and the following nodal stations: cervical, axillary, mediastinal, hilar, paraaortic, pelvic, inguinal and femoral. Normal organs including the medial thyroid, heart, lungs, and abdominal organs were shielded with multi-leaf collimators using three-dimensional conformal technique (Figure 1, 2). Of 12 patients with benign conditions, all are alive at last follow up. Of 10 patients with malignant conditions, 3 are dead from disease. Five out of 12 patients who had haploidentical grafts, 0/2 matched sibling graft and 1/2 unrelated grafts experienced rejection. The median follow up is 14.0 months (IQR 6-41.5). None developed acute pneumonitis. One patient developed thyroid cancer 14 years after TLI. Herein we describe our TLI experience and technique. More studies should be undertaken to evaluate the safety and efficacy of TLI compared to TBI. Going forward, a consensus on technique and dose should be developed.

Cardiac safe hematopoietic stem cell transplantation for systemic sclerosis with poor cardiac function: a pilot safety study that decreases neutropenic interval to 5 days.

We compared three fludarabine-based regimens for systemic sclerosis patients with a high-risk cardiac phenotype that according to EBMT criteria would be a contraindication for a high-dose cyclophosphamide (200 mg/kg) transplant regimen. All three regimens included fludarabine, ATG, and cyclophosphamide (60 mg/kg), while two regimens also included rituximab with or without IVIG. Treatment related mortality (TRM) was 2.4%. The mean number of days of neutropenia (ANC < 500) was 5.2, the mean number of platelet and red blood cell transfusions was 0.3 and 1.85, respectively. Skin score, forced vital capacity (FVC), and total lung capacity (TLC) improved with all three regimens. For patients whose regimen did not include rituximab versus those that included rituximab, 1-year overall relapse rate was higher 36% (5/14) versus 3.6% (1 of 28) (p = 0.01), secondary autoimmune diseases were higher 21% (3/14) versus 0% (0/28) (p = 0.03), and upper respiratory tract infections were higher 28% (4/14) versus 3.6% (1/28) (p = 0.04). In this safety study, a fludarabine-based regimen was relatively safe with a TRM of 2.4% and a neutropenic interval of only 5.2 days in systemic sclerosis patients with a high-risk cardiac phenotype. The addition of rituximab decreased 1-year relapse rate, risk of late secondary autoimmune diseases, and upper-respiratory tract infections.

Three‐dimensional collagenous niche and azacytidine selectively promote time‐dependent cardiomyogenesis from human bone marrow‐derived MSC spheroids

Endogenous adult cardiac regenerative machinery is not capable of replacing the lost cells following myocardial infarction, often leading to permanent alterations in structure-function-mechanical properties. Regenerative therapies based on delivering autologous stem cells within an appropriate 3D milieu could meet such demand, by enabling homing and directed differentiation of the transplanted cells into lost specialized cell populations. Since type I collagen is the predominant cardiac tissue matrix protein, we here optimized the 3D niche which could promote time-dependent evolution of cardiomyogenesis from human bone marrow-derived mesenchymal stem cells (BM-MSC). 3D collagen gel physical and mechanical characteristics were assessed using SEM and AFM, respectively, while the standalone and combined effects of collagen concentration, culture duration, and 5-azacytidine (aza) dose on the phenotype and genotype of MSC spheroids were quantified using immunofluorescence labeling and RT-PCR analysis. Increasing collagen concentration led to a significant increase in Young's modulus (p < 0.01) but simultaneous decrease in the mean pore size, resulting in stiffer gels. Spheroid formation significantly modulated MSC differentiation and genotype, mostly due to better cell-cell interactions. Among the aza dosages tested, 10 μM appears to be optimal, while 3 mg/ml gels resulted in significantly lower cell viability compared to 1 or 2 mg/ml gels. Stiffer gels (2 and 3 mg/ml) and exposure to 10 μM aza upregulated early and late cardiac marker expressions in a time-dependent fashion. On the other hand, cell-cell signaling within the MSC spheroids seem to have a strong role in influencing mature cardiac markers expression, since neither aza nor gel stiffness seem to significantly improve their expression. Western blot analysis suggested that canonical Wnt/β-catenin signaling pathway might be primarily mediating the observed benefits of aza on cardiac differentiation of MSC spheroids. In conclusion, 2 mg/ml collagen and 10 μM aza appears to offer optimal 3D microenvironment in terms of cell viability and time-dependent evolution of cardiomyogenesis from human BM-MSCs, with significant applications in cardiac tissue engineering and stem cell transplantation for regenerating lost cardiac tissue.

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OBJECTIVES/SPECIFIC AIMS: A major limitation of cardiac stem cell transplantation following myocardial infarction (MI) is poor retention of cells in the ischemic microenvironment. Our study aims to better understand and promote the survival and differentiation of human cardiosphere-derived cells (hCDCs) in anoxia, a feature of infarcted myocardium. METHODS/STUDY POPULATION: We previously demonstrated that TGFβ1 and heparin-containing hydrogels (TH-hydrogel) can promote murine CDC survival. In this study, hCDCs were incubated in either normoxia or anoxia for 8 hours with and without TH-hydrogel. In addition, hCDCs without TH-hydrogel were assessed in 16 hours of anoxia. Following incubation, hCDCs were assayed for viability using calcein dye and immunostained for CD31, a marker of endothelial differentiation. RESULTS/ANTICIPATED RESULTS: hCDCs incubated for 8 hours in anoxia in both models equally demonstrated increased survival up to 30% when compared with cells incubated in normoxia. However, in contrast to hCDCs alone, hCDCs with TH-hydrogel additionally demonstrated increased differentiation into endothelial cells in both anoxia and normoxia. We found that hCDCs alone were able to upregulate CD31 only when subjected to 16 hours of anoxia. DISCUSSION/SIGNIFICANCE OF IMPACT: We demonstrate a new, previously unknown response of hCDCs to anoxia. This induces increased viability and differentiation of hCDCs into endothelial cells. The differentiation in anoxia was time dependent and could be expedited with use of TH-hydrogel. Anoxic preconditioning of hCDCs together with the TH-hydrogel system may improve the therapeutic potential of stem cell transplantation following MI.

Resveratrol activates endogenous cardiac stem cells and improves myocardial regeneration following acute myocardial infarction

Stem cell antigen-1-positive (Sca-1+) cardiac stem cells (CSCs) therapy for myocardial regeneration following acute myocardial infarction (AMI) is limited by insufficient cell viability and a high rate of apoptosis, due to the poor regional microenvironment. Resveratrol, which is a compound extracted from red wine, has been reported to protect myocardial tissue post-AMI by increasing the expression of angiogenic and chemotactic factors. The present study aimed to investigate the effects of resveratrol on Sca-1+ CSCs, and to optimize Sca-1+ CSCs therapy for myocardial regeneration post-AMI. C57/BL6 mice (age, 6 weeks) were divided into two groups, which received intragastric administration of PBS or 2.5 mg/kg.d resveratrol. The endogenous expression of Sca-1+ CSCs in the heart was assessed on day 7. Furthermore, C57/BL6 mice underwent left anterior descending coronary artery ligation for the construction of an AMI model, and received an injection of 1×106 CSCs into the peri-ischemic area (n=8/group). Mice received intragastric administration of PBS or resveratrol (2.5 mg/kg.d) for 4 weeks after cell transplantation. Echocardiography was used to evaluate cardiac function 4 weeks after cell transplantation. Capillary density and cardiomyocyte apoptosis in the peri-ischemic myocardium were assessed by cluster of differentiation 31 immunofluorescent staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, respectively. Western blot analysis was conducted to detect the protein expression levels of vascular endothelial growth factor (VEGF) and stromal cell-derived factor (SDF)-1α in the myocardium. Treatment with resveratrol increased the number of endogenous Sca-1+ CSCs in heart tissue after 7 days (PBS vs. Res, 1.85±0.41/field vs. 3.14±0.26/field, P<0.05). Furthermore, intragastric administration of resveratrol significantly increased left ventricle (LV) function 4 weeks after AMI, as determined by an increase in LV fractional shortening (CSCs vs. Res + CSCs, 28.82±1.58% vs. 31.18±2.02%, P<0.05), reduced LV end-diastolic diameter (CSCs vs. Res + CSCs, 0.37±0.01 mm vs. 0.35±0.02 mm, P<0.05), and reduced LV end-systolic diameter (CSCs vs. Res + CSCs, 0.26±0.01 mm vs. 0.23±0.02 mm, P<0.05). These protective effects were predominantly achieved via an increase in capillary density (CSCs vs. Res + CSCs, 281.02±24.08/field vs. 329.75±36.69/field, P<0.05) and a reduction in cardiomyocyte apoptosis (CSCs vs. Res + CSCs, 1.5±0.54/field vs. 0.83±0.40/field, P<0.05) in peri-ischemic myocardium. Western blot analysis indicated that VEGF and SDF-1α were upregulated in resveratrol-treated myocardium after a 7 day treatment or 4 weeks after AMI (7 days VEGF PBS vs. Res, 0.89±0.07 vs. 1.21±0.02, P<0.05; SDF-1α PBS vs. Res, 0.66±0.04 vs. 1.33±0.04, P<0.05; 4 weeks VEGF CSCs vs. Res + CSCs, 0.54±0.03 vs. 0.93±0.13, P<0.05; SDF-1α CSCs vs. Res + CSCs, 0.53±0.03 vs. 0.93±0.03, P<0.05). Resveratrol activated endogenous CSCs, increased capillary density and decreased cardiomyocyte apoptosis in the peri-ischemic myocardium, and augmented the effects of CSCs transplantation. These effects may be caused by the upregulation of VEGF and SDF-1α.

Cardiac stem cell transplantation with 2,3,5,4′-tetrahydroxystilbehe-2-O-β-d-glucoside improves cardiac function in rat myocardial infarction model

Headings aimsCardiac stem cells (CSCs)-transplanted therapy provides a promising therapy for the ischemic heart disease (IHD), especially in the epidemic of myocardial infarction (MI). The compound 2,3,5,4′-tetrahydroxystilbene-2-O-β-d-glucoside (THSG) can induce CSC proliferation in vitro based on our previous study, so we aimed to study the induce effect of THSG on CSCs-transplanted MI rat in vivo. Materials and methodsUsing a murine model of MI, this study was designed to evaluate the impact of THSG (30, 60, 120mg/kg) on CSCs-based therapy for MI and the underlying mechanism in this process. Key findingThe results showed that THSG on CSCs-transplanted therapy groups (THSG+CSCs groups) can significantly reduce S-T segment elevation, and increase heart rate compared with MI group. The left ventricular ejection fraction (LVEF) and the left ventricular fractional shortening (LVFS) were significantly reduced in THSG+CSCs groups compared to the MI group. The levels of enzyme expression (CK-MB, LDH), the heart weight index (HWI) and myocardial infarct size (IS) were all reduced in THSG+CSCs groups. Moreover, other changes noted during these 28days post-MI, included pathologic changes, as well as increased stem cell antigen-1 (Sca-1) expression, or expression of Nkx2.5, GATA-4, and Connexin 43 in myocardial tissue, and reduced the Caspase-3 expression. SignificanceOur findings indicated that THSG facilitated CSCs-transplanted therapy in MI. These observations may be associated with the inducted of THSG on the proliferation of CSCs in vivo and also, with the subsequent differentiation of additional intrinsic neonatal cardiomyocytes to replace damaged heart tissue.

Cardiac Stem Cells Suppressed Cardiac Nerve Sprouting via Attenuated Oxidative Stress in a Rat Model of Myocardial Infarction

Objective: To investigate whether cardiac stem cells (CSCs) can attenuate oxidative stress and improve sympathetic remodeling in rats following myocardial infarction (MI). Methods: Sprague-Dawley rats were randomly divided into three groups: 1) MI with CSCs transplantation (CSCs group, n=15); 2) MI control (Control group, n=15); 3) sham control group (Sham group, n=10). Two weeks after surgery, the animals were subjected to intramyocardial injection. Four weeks after injection, left ventricular function, level of oxidative stress, cardiac nerve sprouting and nerve growth factor (NGF) expression were determined. Results: At 4 weeks after intramyocardial injection, fractional shortening (FS) and left ventricular ejection fraction (LVEF) markedly decreased in CSCs and control groups. However, systolic function were partly preserved in CSCs group compared with control group (P<0.01). The myocardial malondialdehyde (MDA) content, MDA/Superoxide Dismutase (SOD) ratio, NGF expression and density of tyrosine hydroxylase (TH)-positive nerve in peri-infarct zone was significantly increased in the control group and CSCs group than the sham group (all P<0.01). However, all of these valuables were decreased in CSCs group when compared with control group (all P<0.01 except for NGF expression P< 0.05). Furthermore, a positive correlation was observed between the degree of sympathetic remodeling and the level of MDA/SOD ratio (r=0.86, R2=0.75). Conclusion: CSCs suppressed sympathetic remodeling after MI probably via attenuated oxidative stress and downregulated NGF expression, which in turn leads to a promising treatment for SCD post MI.

Resveratrol Enhances Cardiomyocyte Differentiation of Human Induced Pluripotent Stem Cells through Inhibiting Canonical WNT Signal Pathway and Enhancing Serum Response Factor-miR-1 Axis.

Resveratrol (trans-3,5,4′-trihydroxystilbene) (RSV) is a natural polyphenol with protective effects over cardiac tissues and can affect cell survival and differentiation in cardiac stem cells transplantation. However, whether this agent can affect cardiomyocytes (CMs) differentiation of induced pluripotent stem cells (iPSCs) is not yet clear. This study explored whether RSV can affect CMs differentiation of human iPSCs. Under embryoid bodies (EBs) condition, the effect of RSV on the change of pluripotent markers, endoderm markers, mesoderm markers, and ectoderm markers was measured using qRT-PCR. Under CM differentiation culture, the effect of RSV on CM specific markers was also measured. The regulative role of RSV over canonical Wnt signal pathway and serum response factor- (SRF-) miR-1 axis and the functions of these two axes were further studied. Results showed that RSV had no effect on the self-renewal of human iPSCs but could promote mesoderm differentiation. Under CM differentiation culture, RSV could promote CM differentiation of human iPSCs through suppressing canonical Wnt signal pathway and enhancing SRF-miR-1 axis.

Abstract 18986: Unopposed TNF/TNFR1 Signaling Prevents Therapeutic Benefit From Cardiac Stem Cell Therapy After Reperfused Myocardial Infarction in Mice

Despite expansion of resident cardiac stem cells (CSCs) after myocardial infarction (MI), the heart is unable to regenerate, suggesting that local factors inhibit CSC function. Tumor necrosis factor-α (TNF), increased in infarcted and failing hearts, is one candidate inhibitory factor; its effects are specific to its two receptors (TNFRs). We hypothesized that TNF/TNFR signaling in CSCs modulates the efficacy of CSC therapy after reperfused MI in mice. Magnetically sorted, c-kit enriched, Lin– CSCs were isolated from wild-type (WT), TNFR1-/-, and TNFR2-/- mice, expanded, and 1 x 105 CSCs were administered via intramyocardial injection in the border zone 48 h after 60 min ischemia in WT C57BL/6 mice (n = 13-18/group). Five weeks after CSC therapy, as compared with PBS-injected MI mice, WT CSC transplantation significantly (p&lt;0.05) improved LV systolic function (ESV 50 ± 14 vs 63 ± 23 μL; EF 31 ± 11 vs 24 ± 9%). Analogous to WT CSCs, TNFR1-/- CSCs also significantly improved LV systolic function (ESV 44 ± 5 uL; EF 35 ± 3%). In contrast, TNFR2-/- CSC transplanted MI hearts exhibited greater LV systolic dysfunction (ESV 62 ± 5 uL; EF 29 ± 4%) as compared with both WT and TNFR1-/- CSC injected hearts, and were comparable to PBS-injected MI hearts. There was signficantly reduced border zone (BZ) fibrosis in both WT (7.6 ± 3.2%) and TNFR1-/- CSC (7.2 ± 1.9%) injected hearts as compared with either PBS-injected MI hearts (11.6 ± 2.8%), or TNFR2-/- CSC injected MI hearts (15.7 ± 4.0%). Analogous to fibrotic change, cardiomyocyte hypertrophy in post-MI hearts was significantly decreased after cell transplantation with either WT CSCs (322 ± 56 μm2) or TNFR1-/- CSCs (244 ± 29 μm2), as compared with PBS-injected MI hearts (423 ± 56 μm2), with more robust improvements in hypertrophy in the TNFR1-/- CSC MI hearts. In contrast, cardiomyocyte size after TNFR2-/- CSC transplantation (389 ± 58 μm2) was comparable to PBS injected hearts, and significantly greater than either WT or TNFR1-/- CSC injected MI hearts. We conclude that myocardial TNF diminishes the efficacy of CSC therapy via TNFR1 signaling, especially when unopposed by concomitant TNFR2 signaling. Selective TNFR1 blockade, or TNFR2 agonism, at the time of cell transplantation may improve the functional outcomes of CSC therapy after MI.

GW26-e1464 PHA665752, Hepatocyte Growth Factor/c-Met Inhibitor, Reduces the Ventricular Fibrillation Threshold in Myocardial Infarction Rats Treated with Cardiac Stem Cells Transplantation.

GW26-e1464 PHA665752, Hepatocyte Growth Factor/c-Met Inhibitor, Reduces the Ventricular Fibrillation Threshold in Myocardial Infarction Rats Treated with Cardiac Stem Cells Transplantation.

The characterization of cardiac stem cells obtained from patients who have received left ventriculoplasty

The recent clinical application of c-kit-positive resident cardiac stem cells (CSCs) for severe heart failure patients revealed their remarkable and long lasting beneficial effects. Ultimately aiming at a combined therapy of left ventriculoplasty and autologous CSC transplantation, we have successfully isolated and cultivated endogenous stem cells from the right atrium and the infarcted left ventricle, respectively, of all subjects in the target population. Three independent parameters, population doubling time, BrdU incorporation, and colony forming ability, each of which indicates the growth property of cultured CSCs, correlated well in every sample. Overall, CSCs derived from both origins possessed a great proliferative potential with a non-significant superiority in the right atrial CSCs. This brief report provides a fundamental basis for regenerative therapy as a potential novel management of ischemic cardiomyopathy, following the ventriculoplasty.

VEGF-A promotes cardiac stem cell engraftment and myocardial repair in the infarcted heart

BackgroundThe objective of this study was to determine whether vascular endothelial growth factor (VEGF)-A subtypes improve cardiac stem cell (CSC) engraftment and promote CSC-mediated myocardial repair in the infarcted heart. MethodsCSCs were treated with VEGF receptor (VEGFR) inhibitors, VCAM-1 antibody (VCAM-1-Ab), or PKC-α inhibitor followed by the treatment with VEGF-A. CSC adhesion assays were performed in vitro. In vivo, the PKH26-labeled and VCAM-1-Ab or PKC-α inhibitor pre-treated CSCs were treated with VEGF-A followed by implantation into infarcted rat hearts. The hearts were then collected for measuring CSC engraftment and evaluating cardiac fibrosis and function 3 or 28days after the CSC transplantation. ResultsAll three VEGF-A subtypes promoted CSC adhesion to extracellular matrix and endothelial cells. VEGF-A-mediated CSC adhesion required VEGFR and PKCα signaling. Importantly, VEGF-A induced VCAM-1, but not ICAM-1 expression in CSCs through PKCα signaling. In vivo, VEGF-A promoted the engraftment of CSCs in infarcted hearts, which was attenuated by PKCα inhibitor or VCAM-1-Ab. Moreover, VEGF-A-mediated CSC engraftment resulted in a reduction in infarct size and fibrosis. Functional studies showed that the transplantation of the VEGF-A-treated CSCs stimulated extensive angiomyogenesis in infarcted hearts as indicated by the expression of cardiac troponin T and von Willebrand factor, leading to an improved performance of left ventricle. Blockade of PKCα signaling or VCAM-1 significantly diminished the beneficial effects of CSCs treated with VEGF-A. ConclusionVEGF-A promotes myocardial repair through, at least in part, enhancing the engraftment of CSCs mediated by PKCα/VCAM-1 pathway.

Abstract 15555: Administration of c-Kit+ Cardiac Stem Cells (CSCs) Results in Increased Proliferation and Cardiac Content of CSCs 1 Year Later

Background: We have previously shown in rats that the beneficial effects of c-kit + CSCs on LV function and remodeling post-myocardial infarction persist for at least 1 year after CSC administration. However, in that study the retention of transplanted Y-chromosome + cells in the risk region (RR) of female rat hearts at 1 year was low (&lt;10% of total nuclei) and not sufficient to account for the functional improvement, suggesting that other mechanisms must be at work. Methods and Results: To address this issue, rats received intracoronary vehicle or 1x10 6 syngeneic CSCs 4 h after a 90-min coronary occlusion; 11 months later, BrdU treatment was given for 1 month. CSCs, which are c-kit + /CD45 − , were distinguished from c-kit + hematopoietic stem cells/mast cells, which are CD45 + . At 1 year after CSC administration, the total number of c-kit + or c-kit + /BrdU + cells in the heart (the sum of c-kit + /CD45 − and c-kit + /CD45 + cells) did not differ between CSC and control groups (Figs. H and I). However, CSC transplantation resulted in increased numbers of CSCs (c-kit + /CD45 − cells) in the RR (i.e., the infarct zone plus border zone)(47.6±7.0% of total c-kit + cells vs. 27.9±4.1% in vehicle group; n=5, P &lt;0.05; Fig. J). Among CSCs (c-kit + /CD45 − cells), the fraction that was newly formed (c-kit + /CD45 − /BrdU + ) was dramatically increased in the RR of the CSC group (+ 2.6-fold vs. vehicle group; n=4, P &lt;0.05; Fig. M), indicating increased CSC proliferation and turnover. Conclusions: These data reveal, for the first time, that a single intracoronary infusion of CSCs is followed by an increase in both the proliferation and the total number of c-kit + CSCs in the myocardium that persists, surprisingly, for at least 1 year after cell delivery. Since transplanted cells do not differentiate into adult myocytes, these data suggest that the long-term salubrious effects of CSCs on cardiac function are mediated by sustained activation of the CSC pool in the heart.

GW25-e0091 Effects of Cardiac Stem Cells Transplantation on the Ventricular Fibrillation Threshold in Rats with Myocardial Infarction in Short-Term, Medium-Term and Long-Term Period

Arrhythmia is of concern after cardiac stem cells (CSCs) transplantation in repairing infarcted myocardium. However, whether transplanted CSCs improved ventricular fibrillation threshold (VFT) in the myocardial infarction model is still unclear. We sought to investigate the VFT in rats with

GW25-e0865 Cardiac Stem Cell Transplantation Improve Electrophysiological Stability in Rats with Myocardial Infarction via Inhibition of TGF-β1 Pathway

Whether cardiac stem cells (CSCs) and mesenchymal stem cells (MSCs) transplantation improved electrophysiological stability in rats with myocardial infarction (MI) is still unclear. We sought to compare the effects of the CSCs and MSCs transplantation on the electrophysiological characteristics in

Comparison of Cardiac Stem Cells and Mesenchymal Stem Cells Transplantation on the Cardiac Electrophysiology in Rats with Myocardial Infarction

Whether transplanted cardiac stem cells (CSCs) and mesenchymal stem cells (MSCs) improved ventricular fibrillation threshold (VFT) similarly is still unclear. We sought to compare the effects of the CSC and MSC transplantation on the electrophysiological characteristics and VFT in rats with myocardial infarction (MI). MI was induced in 30 male Sprague-Dawley rats. Two weeks later, animals were randomized to receive 5 × 10(6) CSCs labeled with PKH26 in PBS or 5 × 10(6) MSCs labeled with PKH26 in phosphate buffer solution(PBS) or PBS alone injection into the infarcted anterior ventricular free wall. Six weeks after the injection, electrophysiological characteristics and VFT were measured. Labeled CSCs and MSCs were observed in 5μm cryostat sections from each heart. Malignant ventricular arrhythmias were significantly (P = 0.0055) less inducible in the CSC group than the MSC group. The VFTs were improved in the CSC group compared with the MSC group. Labeled CSCs and MSCs were identified in the infarct zone and infarct marginal zone. Labeled CSCs expressed Connexin-43, von Willebrand factor, α-smooth muscle actin and α-sarcomeric actin,while the Labeled MSCs expressed von Willebrand factor, α-smooth muscle actin and α-sarcomeric actin in vivo. After 6weeks of cell transplantation, CSCs are superior to MSCs in modulating the electrophysiological abnormality and improving the VFT in rats with MI. CSCs and MSCs express markers that suggest muscle, endothelium and vascular smooth muscle phenotypes in vivo, but MSCs rarely express Connexin-43.

Improvements of cardiac electrophysiologic stability and ventricular fibrillation threshold in rats with myocardial infarction treated with cardiac stem cells*

Arrhythmia is of concern after cardiac stem cell transplantation in repairing infarcted myocardium. However, whether transplantation improved the ventricular fibrillation threshold and whether severe malignant ventricular arrhythmia is induced in the myocardial infarction model are still unclear. We sought to investigate the electrophysiologic characteristics and ventricular fibrillation threshold in rats with myocardial infarction by treatment with allogeneic cardiac stem cells. Prospective, randomized, controlled study. University-affiliated hospital. Male Sprague-Dawley rats. Myocardial infarction was induced in 20 male Sprague-Dawley rats. Two weeks later, animals were randomized to receive 5 × 10(6) cardiac stem cells labeled with PKH26 in phosphate buffer solution or a phosphate buffer solution-alone injection into the infarcted anterior ventricular-free wall. Six weeks after the cardiac stem cell or phosphate buffer solution injection, electrophysiologic characteristics and ventricular fibrillation threshold were measured at the infarct area, infarct marginal zone, and noninfarct zone. Labeled cardiac stem cells were observed in 5-μm cryostat sections from each harvested heart. The unipolar electrogram activation recovery time dispersions were shorter in the cardiac stem cell group compared with those at the phosphate buffer solution group (15.5 ± 4.4 vs. 38.6 ± 14.9 msecs, p = .000177). Malignant ventricular arrhythmias were significantly (p = .00108) less inducible in the cardiac stem cell group (one of ten) than the phosphate buffer solution group (nine of ten). The ventricular fibrillation thresholds were greatly improved in the cardiac stem cell group compared with the phosphate buffer solution group. Labeled cardiac stem cells were identified in the infarct zone and infarct marginal zone and expressed Connexin-43, von Willebrand factor, α-smooth muscle actin, and α-sarcomeric actin. Cardiac stem cells may modulate the electrophysiologic abnormality and improve the ventricular fibrillation threshold in rats with myocardial infarction treated with allogeneic cardiac stem cells and cardiac stem cell express markers that suggest muscle, endothelium, and vascular smooth muscle phenotypes in vivo.

70 The HeartMate II Risk Score: Predicting Survival in Candidates for Left Ventricular Assist Device Support

Purpose: Nearly one-third of children diagnosed with dilated cardiomyopathy (DCM) receive a transplant or die within the first year after diagnosis. Limited long-term outcome of heart transplantation and scarcity of young donors justify every effort to improve medical therapy and to find alternative therapeutic approaches. There is increasing evidence that cardiac stem cell transplantation induce sustained improvement in cardiac function in patients with heart failure. We describe the compassionate use of intracoronary autologous peripheral stem cell therapy in two young infants diagnosed with DCM and severe heart failure. Methods and Materials: Descriptive study that analyzes the evolution of two pediatric patients diagnosed with DCM and severe heart failure, and who were treated with intracoronary infusion of autologous stem cells. Patient 1 is a 3-month male infant weighing 4 Kg. Patient 2 is a 4-month male infant weighing 5 Kg. Results: At the time of admission, both patients were in poor clinical status (NYHA IV), had high levels of NT-ProBNP and severe LV dilation and systolic dysfunction (EF 30%). Both were mechanically ventilated and needed IV inotropes. Endomyocardial biopsy ruled out myocarditis. In each case, after treatment with G-CSF for 4 days, autologous stem cells were recovered from peripheral blood, implanting them via the coronary arteries afterwards. As soon as one week after the procedure, echocardiography showed a remarkable improvement in LV dilation. One month later a significant gain in their EF ( 40%) was also detected and this was maintained over time. The long-term outcome was favorable. Although first patient has shown LV dilation 17 weeks after the procedure, he is still in functional class I and has adequate weight gain. Conclusions: Although currently heart transplantation is the only established treatment for DCM, stem cell therapy could be an option to improve clinical status, and serve as a bridge to decision, to transplantation or, more importantly, to recovery for these very sick children.