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Chemokine induced migration of human mesenchymal stem cells: A strategy for directing cardiac repair
Vol. 199, No. 3S, September 2004
Cardiothoracic Surgery II
RESULTS: Transplanted lungs displayed strong and linear correlation between PET signals and gamma counter radioactivity (r2 ⫽ 0.82, p ⬍ 0.01). PET imaging also correlated with tissue TK activity (r2 ⫽ 0.44, p ⬍ 0.01). There was no difference in apparent lung volumes by PET between transplanted lungs with and without I/R injury and rejection. CONCLUSIONS: PET imaging is a sensitive and quantitative method for characterizing pulmonary transgene expression in experimental lung transplantation. Characterization of transgene expression is not adversely affected by I/R injury or graft rejection.
Engineering mesenchymal stem cells with hypoxiaregulated gene system: A promising approach for effective cell therapy Yao Liang Tang MD, PhD, M Ian Phillips PhD, DSc, Vinay Badhwar MD, FACS University of South Florida St. Petersburg, FL INTRODUCTION: Autologous mesenchymal stem cells (MSCs) can improve postinfarcted cardiac function. However, progress in cell therapy is hampered by poor viability of implanted cells and the vulnerability of regenerated tissue to repeated bouts of ischemia. We developed a novel vigilant vector system, which can sense the hypoxia and regulate human heme-oxygenase(hHO-1) expression. We hypothesize that engineering MSCs with a vigilant system could increase the survival of engrafted cells and protect regenerated myocardium from further injury. METHODS: Mouse MSCs were transfected with the vigilant vector. We assessed the effect of in-vitro hypoxia and in-vivo ischemia on cell apoptosis and cardiac function. In the study, 1x106 of vigilant hHO-1 transfected-MSCs (MSC-VHO-1), vigilant lacZ transfected MSCs (MSC-VlacZ), or MSCs with 50l control medium were injected into syngeneic adult BALB/c mouse hearts 1 hour after induction of myocardial infarction. RESULTS: The implanted MSC-VHO-1 expressed hHO-1 in the ischemic region. MSC-VHO-1 hearts had a 2-fold reduction in the number of apoptotic MSCs compared to the MSC-VlacZ group (p ⫽ 0.001) and control MSCs (p⬍0.001). Immunostaining showed thriving MSCs differentiated toward a myogenic phenotype. Systolic function, assessed by maximum dP/dt, was markedly improved in the MSC-VHO-1 group compared to the MSCVlacZ and MSCs groups.
Expansion index Fibrosis area of LV (%)
Medium
MSCVHO-1
MSCVlacZ
MSCs
1.99 ⫾ 0.39
0.61 ⫾ 0.18§
1.46 ⫾ 0.28
1.46 ⫾ 0.30
36.00 ⫾ 4.36
11.83 ⫾ 3.54§
23.20 ⫾ 5.45
24.40 ⫾ 4.45
LV ⫹dP/dt max (mmHg/s)
3004.57 ⫾ 362.74 5717.07 ⫾ 935.37#* 4336.60 ⫾ 515.10 3988.35 ⫾ 450.07
LV ⫺dP/dt min (mmHg/s)
2447.17 ⫾ 621.96 4893.33 ⫾ 1435.09#* 3642.08 ⫾ 667.03 3559.02 ⫾ 713.01
Values are mean ⫾ SEM; LV ⫹dP/dtmax ⫽ left ventricular maximum rate of isovolumic pressure development; LV ⫺dP/dtmax ⫽ left ventricular minimum rate of isovolumic pressure decay; n ⫽ 6 in each group; §p ⬍ 0.01 vs medium, MSCVlacZ and MSCs groups; #p ⬍ 0.05 vs MSCVlacZ; *p ⬍ 0.01 vs both medium and MSCs.
S33
CONCLUSIONS: Engineering MSCs with vigilant hHO-1 vector can enhance the viability of implanted MSCs in ischemic myocardium, prevent left ventricular remodeling, and improve contractile function. This is the first evidence of using physiologically inducible expression of therapeutic genes for improving survival of graft stem cells in ischemic milieu.
Chemokine induced migration of human mesenchymal stem cells: A strategy for directing cardiac repair Paul B Bolno MD, Doris Morgan PhD, Andrew Wechsler MD, J Yasha Kresh PhD Drexel University College of Medicine Philadelphia, PA INTRODUCTION: The mechanism by which bone marrow stem cells target an area of cardiac injury following myocardial infarction is unknown. Our hypotheses were: [1] granulocyte colonystimulating factor (G-CSF) enhances the migration of human mesenchymal stem cells (hMSC) towards the chemokine, stromal-derived factor (SDF-1), and [2] CXCR4, the receptor for SDF-1, is required for the hMSC migration. SDF-1 and G-CSF are released during a myocardial infarction, and thus may play a role in stem cell mobilization and attraction. METHODS: Migration assays were performed in dual-chamber culture wells containing 8-micron pore size matrigel inserts. SDF-1 was placed in the bottom chamber in all wells except for the control. Sternal bone marrow derived hMSCs were plated into upper chambers containing serum-free medium with and without G-CSF. After 24 hours, migrated cells were isolated and quantified using fluorescent staining. Membrane phenotyping was performed by immunofluorescence using a panel of monoclonal antibodies. RESULTS: hMSC migration in response to SDF-1 was 11.4%(p⬍.02) greater than in control wells and 34%(p⬍.001)greater when hMSC were pre-exposed to G-CSF. The hMSCs expressed the membrane phenotype CD34(-), CD14(-), CXCR4(-), CD44(⫹), CD105(⫹), CD106(⫹). CONCLUSIONS: Exposing hMSCs to G-CSF can significantly enhance the homing capacity of these stem cells towards SDF-1. This chemoattraction did not require the SDF-1 receptor, CXCR4. Ongoing experiments suggest G-CSF may have enhanced stem cell migration through an interaction with the CD44(⫹) receptor, a homing cell adhesion molecule. Directing and amplifying the homing of endogenous stem cells, using pro-inflammatory chemokines, is a promising therapeutic strategy for reengineering the damaged myocardium.
Cardiothoracic Surgery II
RESULTS: Transplanted lungs displayed strong and linear correlation between PET signals and gamma counter radioactivity (r2 ⫽ 0.82, p ⬍ 0.01). PET imaging also correlated with tissue TK activity (r2 ⫽ 0.44, p ⬍ 0.01). There was no difference in apparent lung volumes by PET between transplanted lungs with and without I/R injury and rejection. CONCLUSIONS: PET imaging is a sensitive and quantitative method for characterizing pulmonary transgene expression in experimental lung transplantation. Characterization of transgene expression is not adversely affected by I/R injury or graft rejection.
Engineering mesenchymal stem cells with hypoxiaregulated gene system: A promising approach for effective cell therapy Yao Liang Tang MD, PhD, M Ian Phillips PhD, DSc, Vinay Badhwar MD, FACS University of South Florida St. Petersburg, FL INTRODUCTION: Autologous mesenchymal stem cells (MSCs) can improve postinfarcted cardiac function. However, progress in cell therapy is hampered by poor viability of implanted cells and the vulnerability of regenerated tissue to repeated bouts of ischemia. We developed a novel vigilant vector system, which can sense the hypoxia and regulate human heme-oxygenase(hHO-1) expression. We hypothesize that engineering MSCs with a vigilant system could increase the survival of engrafted cells and protect regenerated myocardium from further injury. METHODS: Mouse MSCs were transfected with the vigilant vector. We assessed the effect of in-vitro hypoxia and in-vivo ischemia on cell apoptosis and cardiac function. In the study, 1x106 of vigilant hHO-1 transfected-MSCs (MSC-VHO-1), vigilant lacZ transfected MSCs (MSC-VlacZ), or MSCs with 50l control medium were injected into syngeneic adult BALB/c mouse hearts 1 hour after induction of myocardial infarction. RESULTS: The implanted MSC-VHO-1 expressed hHO-1 in the ischemic region. MSC-VHO-1 hearts had a 2-fold reduction in the number of apoptotic MSCs compared to the MSC-VlacZ group (p ⫽ 0.001) and control MSCs (p⬍0.001). Immunostaining showed thriving MSCs differentiated toward a myogenic phenotype. Systolic function, assessed by maximum dP/dt, was markedly improved in the MSC-VHO-1 group compared to the MSCVlacZ and MSCs groups.
Expansion index Fibrosis area of LV (%)
Medium
MSCVHO-1
MSCVlacZ
MSCs
1.99 ⫾ 0.39
0.61 ⫾ 0.18§
1.46 ⫾ 0.28
1.46 ⫾ 0.30
36.00 ⫾ 4.36
11.83 ⫾ 3.54§
23.20 ⫾ 5.45
24.40 ⫾ 4.45
LV ⫹dP/dt max (mmHg/s)
3004.57 ⫾ 362.74 5717.07 ⫾ 935.37#* 4336.60 ⫾ 515.10 3988.35 ⫾ 450.07
LV ⫺dP/dt min (mmHg/s)
2447.17 ⫾ 621.96 4893.33 ⫾ 1435.09#* 3642.08 ⫾ 667.03 3559.02 ⫾ 713.01
Values are mean ⫾ SEM; LV ⫹dP/dtmax ⫽ left ventricular maximum rate of isovolumic pressure development; LV ⫺dP/dtmax ⫽ left ventricular minimum rate of isovolumic pressure decay; n ⫽ 6 in each group; §p ⬍ 0.01 vs medium, MSCVlacZ and MSCs groups; #p ⬍ 0.05 vs MSCVlacZ; *p ⬍ 0.01 vs both medium and MSCs.
S33
CONCLUSIONS: Engineering MSCs with vigilant hHO-1 vector can enhance the viability of implanted MSCs in ischemic myocardium, prevent left ventricular remodeling, and improve contractile function. This is the first evidence of using physiologically inducible expression of therapeutic genes for improving survival of graft stem cells in ischemic milieu.
Chemokine induced migration of human mesenchymal stem cells: A strategy for directing cardiac repair Paul B Bolno MD, Doris Morgan PhD, Andrew Wechsler MD, J Yasha Kresh PhD Drexel University College of Medicine Philadelphia, PA INTRODUCTION: The mechanism by which bone marrow stem cells target an area of cardiac injury following myocardial infarction is unknown. Our hypotheses were: [1] granulocyte colonystimulating factor (G-CSF) enhances the migration of human mesenchymal stem cells (hMSC) towards the chemokine, stromal-derived factor (SDF-1), and [2] CXCR4, the receptor for SDF-1, is required for the hMSC migration. SDF-1 and G-CSF are released during a myocardial infarction, and thus may play a role in stem cell mobilization and attraction. METHODS: Migration assays were performed in dual-chamber culture wells containing 8-micron pore size matrigel inserts. SDF-1 was placed in the bottom chamber in all wells except for the control. Sternal bone marrow derived hMSCs were plated into upper chambers containing serum-free medium with and without G-CSF. After 24 hours, migrated cells were isolated and quantified using fluorescent staining. Membrane phenotyping was performed by immunofluorescence using a panel of monoclonal antibodies. RESULTS: hMSC migration in response to SDF-1 was 11.4%(p⬍.02) greater than in control wells and 34%(p⬍.001)greater when hMSC were pre-exposed to G-CSF. The hMSCs expressed the membrane phenotype CD34(-), CD14(-), CXCR4(-), CD44(⫹), CD105(⫹), CD106(⫹). CONCLUSIONS: Exposing hMSCs to G-CSF can significantly enhance the homing capacity of these stem cells towards SDF-1. This chemoattraction did not require the SDF-1 receptor, CXCR4. Ongoing experiments suggest G-CSF may have enhanced stem cell migration through an interaction with the CD44(⫹) receptor, a homing cell adhesion molecule. Directing and amplifying the homing of endogenous stem cells, using pro-inflammatory chemokines, is a promising therapeutic strategy for reengineering the damaged myocardium.