Microvascular obstruction identifies a subgroup of patients who benefit from stem cell therapy following ST-elevation myocardial infarction.

BACKGROUND: Microvascular obstruction (MVO) is associated with greater infarct size, adverse left-ventricular (LV) remodeling and reduced ejection fraction following ST-elevation myocardial infarction (STEMI). We hypothesized that patients with MVO may constitute a subgroup of patients that would benefit from intracoronary stem cell delivery with bone marrow mononuclear cells (BMCs) given previous findings that BMCs tended to improve LV function only in patients with significant LV dysfunction. METHODS AND RESULTS: We analyzed the cardiac MRIs of 356 patients (303 M, 53 F) with anterior STEMIs who received autologous BMCs or placebo / control as part of 4 randomized clinical trials that included the Cardiovascular Cell Therapy Research Network (CCTRN) TIME trial and its pilot, the multicenter French BONAMI trial and SWISS-AMI trials. A total of 327 patients had paired imaging data at 1 year. All patients received 100 to 150 million intracoronary autologous BMCs or placebo / control 3 to 7 days following primary PCI and stenting. LV function, volumes, infarct size and MVO were assessed prior to infusion of BMCs and 1 year later. Patients with MVO (n = 210) had reduced LVEF and much greater infarct size and LV volumes compared to patients without MVO (n = 146) (P < .01). At 12 months, patients with MVO who received BMCs had significantly greater recovery of LVEF compared to those patients with MVO who received placebo (absolute difference = 2.7%; P < .05). Similarly, left-ventricular end-diastolic (LVEDVI) and end-systolic volume indices (LVESVI) demonstrated significantly less adverse remodeling in patients with MVO who received BMCs compared to placebo. In contrast, no improvement in LVEF or LV volumes was observed in those patients without MVO who received BMCs compared to placebo. CONCLUSIONS: The presence of MVO on cardiac MRI following STEMI identifies a subgroup of patients who benefit from intracoronary stem cell therapy.

Deconditioning, fatigue and impaired quality of life in long-term survivors after allogeneic hematopoietic stem cell transplantation.

Long-term survivors after allogeneic hematopoietic stem cell transplantation (allo-HSCT) are at high risk for treatment-related adverse events, that may worsen physical capacity and may induce fatigue and disability. The aims of this prospective study were to evaluate exercise capacity in allotransplant survivors and its relationship with fatigue and disability. Patient-reported outcomes and exercise capacity were evaluated in 71 non-relapse patients 1 year after allo-HSCT, using validated questionnaires, cardiopulmonary exercise testing (CPET) with measure of peak oxygen uptake (peakVO2) and deconditioning, pulmonary function testing, echocardiography and 6-min walk test. A high proportion (75.4%) of allo-HSCT survivors showed abnormal cardiopulmonary exercise testing parameters as compared to predicted normal values, including 49.3% patients who exhibited moderate to severe impairment in exercise capacity and 37.7% patients with physical deconditioning. PeakVO2 values were not accurately predicted by 6-min walk distances (r = 0.53). Disability and fatigue were strongly associated with decreased peakVO2 values (p = 0.002 and p = 0.008, respectively). Exercise capacity was reduced in most allo-HSCT long-term survivors. Because reduced exercise capacity was associated with fatigue, disability and a decrease in quality of life, cardiopulmonary exercise testing should be performed in every patient who reports fatigue and disability.

Sustained quality of life improvement after intracoronary injection of autologous bone marrow cells in the setting of acute myocardial infarction: results from the BONAMI trial.

PURPOSE: Cardiac cell therapy is a promising treatment for acute myocardial infarction (AMI), leading to cardiac function improvement. However, whether it translates into quality of life (QoL) improvement is unclear. We hypothesized that administration of bone marrow cells (BMC) to patients with AMI improves QoL. METHODS: In the multicenter BONAMI trial (NCT00200707), patients with reperfused AMI and decreased myocardial viability were randomized to intracoronary autologous BMC infusion (n = 52) or state-of-the-art therapy (n = 49). QoL data, derived from the Minnesota Living with Heart Failure questionnaire (MLHFQ), were obtained 1, 3, and 12 months after AMI and analyzed using a Rasch-family model. RESULTS: Using this model, QoL improved over time in the BMC group (p = 0.025) but not in the control group. Furthermore, the BMC-group patients displayed a better QoL than the control-group patients at 3 and 12 months post-AMI (p = 0.034 and p = 0.003, respectively). These findings were not detected when analyzing MLHFQ data using a standard method. Cardiac function, myocardial viability, mortality, and number of major adverse cardiac events did not differ between treatment groups. CONCLUSION: Our results suggest that BMC therapy can improve QoL, stressing the need for confirmation trials and for systematic QoL assessment in cardiac cell therapy trials .

Mesenchymal Stem Cells Induce Suppressive Macrophages Through Phagocytosis in a Mouse Model of Asthma.

Mesenchymal stem cell (MSC) immunosuppressive functions make them attractive candidates for anti-inflammatory therapy in allergic asthma. However, the mechanisms by which they ensure therapeutic effects remain to be elucidated. In an acute mouse model of house dust mite (Der f)-induced asthma, one i.v. MSC injection was sufficient to normalize and stabilize lung function in Der f-sensitized mice as compared to control mice. MSC injection decreased in vivo airway responsiveness and decreased ex vivo carbachol-induced bronchial contraction, maintaining bronchial expression of the inhibitory type 2 muscarinic receptor. To evaluate in vivo MSC survival, MSCs were labeled with PKH26 fluorescent marker prior to i.v. injection, and 1 to 10 days later total lungs were digested to obtain single-cell suspensions. 91.5 ± 2.3% and 86.6 ± 6.3% of the recovered PKH26(+) lung cells expressed specific macrophage markers in control and Der f mice, respectively, suggesting that macrophages had phagocyted in vivo the injected MSCs. Interestingly, only PKH26(+) macrophages expressed M2 phenotype, while the innate PKH26(-) macrophages expressed M1 phenotype. Finally, the remaining 0.5% PKH26(+) MSCs expressed 10- to 100-fold more COX-2 than before injection, suggesting in vivo MSC phenotype modification. Together, the results of this study indicate that MSCs attenuate asthma by being phagocyted by lung macrophages, which in turn acquire a M2 suppressive phenotype. Stem Cells 2016;34:1836-1845.

Urine-sample-derived human induced pluripotent stem cells as a model to study PCSK9-mediated autosomal dominant hypercholesterolemia.

Proprotein convertase subtilisin kexin type 9 (PCSK9) is a critical modulator of cholesterol homeostasis. Whereas PCSK9 gain-of-function (GOF) mutations are associated with autosomal dominant hypercholesterolemia (ADH) and premature atherosclerosis, PCSK9 loss-of-function (LOF) mutations have a cardio-protective effect and in some cases can lead to familial hypobetalipoproteinemia (FHBL). However, limitations of the currently available cellular models preclude deciphering the consequences of PCSK9 mutation further. We aimed to validate urine-sample-derived human induced pluripotent stem cells (UhiPSCs) as an appropriate tool to model PCSK9-mediated ADH and FHBL. To achieve our goal, urine-sample-derived somatic cells were reprogrammed into hiPSCs by using episomal vectors. UhiPSC were efficiently differentiated into hepatocyte-like cells (HLCs). Compared to control cells, cells originally derived from an individual with ADH (HLC-S127R) secreted less PCSK9 in the media (-38.5%; P=0.038) and had a 71% decrease (P<0.001) of low-density lipoprotein (LDL) uptake, whereas cells originally derived from an individual with FHBL (HLC-R104C/V114A) displayed a strong decrease in PCSK9 secretion (-89.7%; P<0.001) and had a 106% increase (P=0.0104) of LDL uptake. Pravastatin treatment significantly enhanced LDL receptor (LDLR) and PCSK9 mRNA gene expression, as well as PCSK9 secretion and LDL uptake in both control and S127R HLCs. Pravastatin treatment of multiple clones led to an average increase of LDL uptake of 2.19 ± 0.77-fold in HLC-S127R compared to 1.38 ± 0.49 fold in control HLCs (P<0.01), in line with the good response to statin treatment of individuals carrying the S127R mutation (mean LDL cholesterol reduction=60.4%, n=5). In conclusion, urine samples provide an attractive and convenient source of somatic cells for reprogramming and hepatocyte differentiation, but also a powerful tool to further decipher PCSK9 mutations and function.

Predictors of ventricular remodelling in patients with reperfused acute myocardial infarction and left ventricular dysfunction candidates for bone marrow cell therapy: insights from the BONAMI trial.

PURPOSE: Few data are available regarding the relation of left ventricular (LV) mechanical dyssynchrony to remodelling after acute myocardial infarction (MI) and stem cell therapy. We evaluated the 1-year time course of both LV mechanical dyssynchrony and remodelling in patients enrolled in the BONAMI trial, a randomized, multicenter controlled trial assessing cell therapy in patients with reperfused MI. METHODS: Patients with acute MI and ejection fraction (EF) ≤ 45 % were randomized to cell therapy or to control and underwent thallium single-photon emission computed tomography (SPECT), radionuclide angiography, and echocardiography at baseline, 3 months, and 1 year. Eighty-three patients with a comprehensive 1-year follow-up were included. LV dyssynchrony was assessed by the standard deviation (SD) of the LV phase histogram using radionuclide angiography. Remodelling was defined as a 20 % increase in LV end-systolic volume index (LVESVI) at 1 year. RESULTS: At baseline, LVEF, wall motion score index, and perfusion defect size were significantly impaired in the 43 patients (52 %) with LV remodelling (all p < 0.001), without significant increase in LV mechanical dyssynchrony. During follow-up, there was a progressive increase in LV SD (p = 0.01). Baseline independent predictors of LV remodelling were perfusion SPECT defect size (p = 0.001), LVEF (p = 0.01) and a history of hypertension (p = 0.043). Bone marrow cell therapy did not affect the time-course of LV remodelling and dyssynchrony. CONCLUSIONS: LV remodelling 1 year after reperfused MI is associated with progressive LV dyssynchrony and is related to baseline infarct size and ejection fraction, without impact of cell therapy on this process.

Toward Personalized Medicine: Using Cardiomyocytes Differentiated From Urine-Derived Pluripotent Stem Cells to Recapitulate Electrophysiological Characteristics of Type 2 Long QT Syndrome.

BACKGROUND: Human genetically inherited cardiac diseases have been studied mainly in heterologous systems or animal models, independent of patients' genetic backgrounds. Because sources of human cardiomyocytes (CMs) are extremely limited, the use of urine samples to generate induced pluripotent stem cell-derived CMs would be a noninvasive method to identify cardiac dysfunctions that lead to pathologies within patients' specific genetic backgrounds. The objective was to validate the use of CMs differentiated from urine-derived human induced pluripotent stem (UhiPS) cells as a new cellular model for studying patients' specific arrhythmia mechanisms. METHODS AND RESULTS: Cells obtained from urine samples of a patient with long QT syndrome who harbored the HERG A561P gene mutation and his asymptomatic noncarrier mother were reprogrammed using the episomal-based method. UhiPS cells were then differentiated into CMs using the matrix sandwich method.UhiPS-CMs showed proper expression of atrial and ventricular myofilament proteins and ion channels. They were electrically functional, with nodal-, atrial- and ventricular-like action potentials recorded using high-throughput optical and patch-clamp techniques. Comparison of HERG expression from the patient's UhiPS-CMs to the mother's UhiPS-CMs showed that the mutation led to a trafficking defect that resulted in reduced delayed rectifier K(+) current (IKr). This phenotype gave rise to action potential prolongation and arrhythmias. CONCLUSIONS: UhiPS cells from patients carrying ion channel mutations can be used as novel tools to differentiate functional CMs that recapitulate cardiac arrhythmia phenotypes.

Meta-Analysis of Cell-based CaRdiac stUdiEs (ACCRUE) in patients with acute myocardial infarction based on individual patient data.

RATIONALE: The meta-Analysis of Cell-based CaRdiac study is the first prospectively declared collaborative multinational database, including individual data of patients with ischemic heart disease treated with cell therapy. OBJECTIVE: We analyzed the safety and efficacy of intracoronary cell therapy after acute myocardial infarction (AMI), including individual patient data from 12 randomized trials (ASTAMI, Aalst, BOOST, BONAMI, CADUCEUS, FINCELL, REGENT, REPAIR-AMI, SCAMI, SWISS-AMI, TIME, LATE-TIME; n=1252). METHODS AND RESULTS: The primary end point was freedom from combined major adverse cardiac and cerebrovascular events (including all-cause death, AMI recurrance, stroke, and target vessel revascularization). The secondary end point was freedom from hard clinical end points (death, AMI recurrence, or stroke), assessed with random-effects meta-analyses and Cox regressions for interactions. Secondary efficacy end points included changes in end-diastolic volume, end-systolic volume, and ejection fraction, analyzed with random-effects meta-analyses and ANCOVA. We reported weighted mean differences between cell therapy and control groups. No effect of cell therapy on major adverse cardiac and cerebrovascular events (14.0% versus 16.3%; hazard ratio, 0.86; 95% confidence interval, 0.63-1.18) or death (1.4% versus 2.1%) or death/AMI recurrence/stroke (2.9% versus 4.7%) was identified in comparison with controls. No changes in ejection fraction (mean difference: 0.96%; 95% confidence interval, -0.2 to 2.1), end-diastolic volume, or systolic volume were observed compared with controls. These results were not influenced by anterior AMI location, reduced baseline ejection fraction, or the use of MRI for assessing left ventricular parameters. CONCLUSIONS: This meta-analysis of individual patient data from randomized trials in patients with recent AMI revealed that intracoronary cell therapy provided no benefit, in terms of clinical events or changes in left ventricular function. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01098591.

Impact of intracoronary bone marrow cell therapy on left ventricular function in the setting of ST-segment elevation myocardial infarction: a collaborative meta-analysis.

AIMS: The objective of the present analysis was to systematically examine the effect of intracoronary bone marrow cell (BMC) therapy on left ventricular (LV) function after ST-segment elevation myocardial infarction in various subgroups of patients by performing a collaborative meta-analysis of randomized controlled trials. METHODS AND RESULTS: We identified all randomized controlled trials comparing intracoronary BMC infusion as treatment for ST-segment elevation myocardial infarction. We contacted the principal investigator for each participating trial to provide summary data with regard to different pre-specified subgroups [age, diabetes mellitus, time from symptoms to percutaneous coronary intervention, infarct-related artery, LV end-diastolic volume index (EDVI), LV ejection fraction (EF), infarct size, presence of microvascular obstruction, timing of cell infusion, and injected cell number] and three different endpoints [change in LVEF, LVEDVI, and LV end-systolic volume index (ESVI)]. Data from 16 studies were combined including 1641 patients (984 cell therapy, 657 controls). The absolute improvement in LVEF was greater among BMC-treated patients compared with controls: [2.55% increase, 95% confidence interval (CI) 1.83-3.26, P < 0.001]. Cell therapy significantly reduced LVEDVI and LVESVI (-3.17 mL/m², 95% CI: -4.86 to -1.47, P < 0.001; -2.60 mL/m², 95% CI -3.84 to -1.35, P < 0.001, respectively). Treatment benefit in terms of LVEF improvement was more pronounced in younger patients (age <55, 3.38%, 95% CI: 2.36-4.39) compared with older patients (age ≥ 55 years, 1.77%, 95% CI: 0.80-2.74, P = 0.03). This heterogeneity in treatment effect was also observed with respect to the reduction in LVEDVI and LVESVI. Moreover, patients with baseline LVEF <40% derived more benefit from intracoronary BMC therapy. LVEF improvement was 5.30%, 95% CI: 4.27-6.33 in patients with LVEF <40% compared with 1.45%, 95% CI: 0.60 to 2.31 in LVEF ≥ 40%, P < 0.001. No clear interaction was observed between other subgroups and outcomes. CONCLUSION: Intracoronary BMC infusion is associated with improvement of LV function and remodelling in patients after ST-segment elevation myocardial infarction. Younger patients and patients with a more severely depressed LVEF at baseline derived most benefit from this adjunctive therapy.

Difference in mobilization of progenitor cells after myocardial infarction in smoking versus non-smoking patients: insights from the BONAMI trial.

INTRODUCTION: Although autologous bone marrow cell (BMC) therapy has emerged as a promising treatment for acute myocardial infarction (AMI), trials reported mixed results. In the BONAMI trial, active smoking reduced cardiac function recovery after reperfused AMI. Therefore, we hypothesized that variability in the functionality of BMCs retrieved from patients with cardiovascular risk factors may partly explain these mixed results. We investigated the characteristics of progenitor cells in active smokers and non-smokers with AMI and their potential impact on BMC therapy efficacy. METHODS: Bone marrow and blood samples from 54 smoking and 47 non-smoking patients enrolled in the BONAMI cell therapy trial were analyzed. RESULTS: The white BMC and CD45dimCD34+ cell numbers were higher in active smokers (P = 0.001, P = 0.03, respectively). In marked contrast, either bone marrow or blood endothelial progenitor CD45dimCD34 + KDR + cells (EPCs) were decreased in active smokers (P = 0.005, P = 0.04, respectively). Importantly, a multivariate analysis including cardiovascular risk factors confirmed the association between active smoking and lower EPC number in bone marrow (P = 0.04) and blood (P = 0.04). Furthermore, baseline circulating EPC count predicted infarct size decrease at three months post-AMI in non-smokers (P = 0.01) but not in active smokers. Interestingly, baseline circulating EPCs were no longer predictive of cardiac function improvement in the BMC therapy group. CONCLUSIONS: These data suggest that circulating EPCs play an important role in cardiac repair post-AMI only in non-smokers and that active smoking-associated EPC alterations may participate in the impairment of cardiac function recovery observed in smokers after AMI, an effect that was overridden by BMC therapy.

Intramyocardial delivery of mesenchymal stem cell-seeded hydrogel preserves cardiac function and attenuates ventricular remodeling after myocardial infarction.

BACKGROUND: To improve the efficacy of bone marrow-derived mesenchymal stem cell (MSC) therapy targeted to infarcted myocardium, we investigated whether a self-setting silanized hydroxypropyl methylcellulose (Si-HPMC) hydrogel seeded with MSC (MSC+hydrogel) could preserve cardiac function and attenuate left ventricular (LV) remodeling during an 8-week follow-up study in a rat model of myocardial infarction (MI). METHODOLOGY/PRINCIPAL FINDING: Si-HPMC hydrogel alone, MSC alone or MSC+hydrogel were injected into the myocardium immediately after coronary artery ligation in female Lewis rats. Animals in the MSC+hydrogel group showed an increase in cardiac function up to 28 days after MI and a mid-term prevention of cardiac function alteration at day 56. Histological analyses indicated that the injection of MSC+hydrogel induced a decrease in MI size and an increase in scar thickness and ultimately limited the transmural extent of MI. These findings show that intramyocardial injection of MSC+hydrogel induced short-term recovery of ventricular function and mid-term attenuation of remodeling after MI. CONCLUSION/SIGNIFICANCE: These beneficial effects may be related to the specific scaffolding properties of the Si-HPMC hydrogel that may provide the ability to support MSC injection and engraftment within myocardium.

Signaling by the matrix proteoglycan decorin controls inflammation and cancer through PDCD4 and MicroRNA-21.

The mechanisms linking immune responses and inflammation with tumor development are not well understood. Here, we show that the soluble form of the extracellular matrix proteoglycan decorin controls inflammation and tumor growth through PDCD4 (programmed cell death 4) and miR-21 (microRNA-21) by two mechanisms. First, decorin acted as an endogenous ligand of Toll-like receptors 2 and 4 and stimulated production of proinflammatory molecules, including PDCD4, in macrophages. Second, decorin prevented translational repression of PDCD4 by decreasing the activity of transforming growth factor-ß1 and the abundance of oncogenic miR-21, a translational inhibitor of PDCD4. Moreover, increased PDCD4 abundance led to decreased release of the anti-inflammatory cytokine interleukin-10, thereby making the cytokine profile more proinflammatory. This pathway operates in both pathogen-mediated and sterile inflammation, as shown here for sepsis and growth retardation of established tumor xenografts, respectively. Decorin was an early response gene evoked by septic inflammation, and protein concentrations of decorin were increased in the plasma of septic patients and mice. In cancer, decorin reduced the abundance of anti-inflammatory molecules and increased that of proinflammatory molecules, thereby shifting the immune response to a proinflammatory state associated with reduced tumor growth. Thus, by stimulating proinflammatory PDCD4 and decreasing the abundance of miR-21, decorin signaling boosts inflammatory activity in sepsis and suppresses tumor growth.

Autologous bone marrow cells and ischemic cardiomyopathy.

Evaluation of: Williams AR, Trachtenberg B, Velazquez DL et al. Intramyocardial stem cell injection in patients with ischemic cardiomyopathy: functional recovery and reverse remodeling. Circ. Res. 108, 792-796 (2011). Transcatheter, intramyocardial injections of bone marrow-derived cells produce reverse remodeling in large animal models of ischemic cardiomyopathy. A variety of adult stem and progenitor cells from different sources have already been examined for their potential to promote cardiac repair and regeneration after myocardial infarction. This article reviews a recent study by Williams et al. who test the hypothesis that transcatheter, intramyocardial injections of autologous bone marrow progenitor cells (mononuclear or mesenchymal stem cells) in left ventricular scar and border zone improve regional contractility of a chronic myocardial scar and that these changes predict subsequent reverse remodeling. All patients tolerated the procedure with no serious adverse events. At 1 year, cardiac MRI demonstrated a decrease in end diastolic volume, a trend toward decreased end systolic volume, decreased infarct size and improved regional left ventricular function. This article focuses on the findings and limitations of the study and provides an insight for future promising clinical trials.

Carotid and femoral atherosclerotic plaques show different morphology.

OBJECTIVE: Results of endovascular repair vary according to the arterial bed. We hypothesized that these differences may be related to the plaque features. To explore this hypothesis, we designed a prospective study that compared carotid and femoral atheroma. METHODS AND RESULTS: Patients that underwent femoral or carotid endarterectomy were included in our study. Demographic data and blood sampling were obtained prior to surgery. Plaques were evaluated for AHA grading, calcification and lipid content. Eighty-eight plaques were harvested during this study (45 carotid specimens and 43 femoral specimens). No differences were noted between carotid and femoral groups regarding demographic and biological data. Histological data more frequently showed fibrous cap atheroma in carotid arteries (75%) and fibrocalcific plaques in femoral arteries (93%), p<0.001. Morphological analyses showed a high prevalence of osteoid metaplasia in femoral arteries (63%) compared to carotid arteries (20%, p<0.001). Biochemical analyses were consistent with histological data, showing higher calcium and lesser cholesterol concentrations in femoral than in carotid plaques (p<0.01). CONCLUSIONS: Femoral and carotid plaques showed different morphology in comparable groups of patients.

Intracoronary autologous mononucleated bone marrow cell infusion for acute myocardial infarction: results of the randomized multicenter BONAMI trial.

AIMS: Intracoronary administration of autologous bone marrow cells (BMCs) leads to a modest improvement in cardiac function, but the effect on myocardial viability is unknown. The aim of this randomized multicentre study was to evaluate the effect of BMC therapy on myocardial viability in patients with decreased left ventricular ejection fraction (LVEF) after acute myocardial infarction (AMI) and to identify predictive factors for improvement of myocardial viability. METHODS AND RESULTS: One hundred and one patients with AMI and successful reperfusion, LVEF ≤45%, and decreased myocardial viability (resting Tl201-SPECT) were randomized to either a control group (n = 49) or a BMC group (n = 52). Primary endpoint was improvement of myocardial viability 3 months after AMI. Baseline mean LVEF measured by radionuclide angiography was 36.3 ± 6.9%. Bone marrow cell infusion was performed 9.3 ± 1.7 days after AMI. Myocardial viability improved in 16/47 (34%) patients in the BMC group compared with 7/43 (16%) in the control group (P = 0.06). The number of non-viable segments becoming viable was 0.8 ± 1.1 in the control group and 1.2 ± 1.5 in the BMC group (P = 0.13). Multivariate analysis including major post-AMI prognostic factors showed a significant improvement of myocardial viability in BMC vs. control group (P = 0.03). Moreover, a significant adverse role for active smoking (P = 0.04) and a positive trend for microvascular obstruction (P = 0.07) were observed. CONCLUSION: Intracoronary autologous BMC administration to patients with decreased LVEF after AMI was associated with improvement of myocardial viability in multivariate-but not in univariate-analysis. A large multicentre international trial is warranted to further document the efficacy of cardiac cell therapy and better define a group of patients that will benefit from this therapy. CLINICAL TRIAL REGISTRATION INFORMATION: URL: http://www.clinicaltrials.gov. Unique identifier NCT00200707.

Cell distribution after intracoronary bone marrow stem cell delivery in damaged and undamaged myocardium: implications for clinical trials.

INTRODUCTION: Early randomized clinical trials of autologous bone marrow cardiac stem cell therapy have reported contradictory results highlighting the need for a better evaluation of protocol designs. This study was designed to quantify and compare whole body and heart cell distribution after intracoronary or peripheral intravenous injection of autologous bone marrow mononuclear cells in a porcine acute myocardial infarction model with late reperfusion. METHODS: Myocardial infarction was induced using balloon inflation in the left coronary artery in domestic pigs. At seven days post-myocardial infarction, 1 x 10(8) autologous bone marrow mononuclear cells were labeled with fluorescent marker and/or 99mTc radiotracer, and delivered using intracoronary or peripheral intravenous injection (leg vein). RESULTS: Scintigraphic analyses and Upsilon-emission radioactivity counting of harvested organs showed a significant cell fraction retained within the heart after intracoronary injection (6 +/- 1.7% of injected radioactivity at 24 hours), whereas following peripheral intravenous cell injection, no cardiac homing was observed at 24 hours and cells were mainly detected within the lungs. Importantly, no difference was observed in the percentage of retained cells within the myocardium in the presence or absence of myocardial infarction. Histological evaluation did not show arterial occlusion in both animal groups and confirmed the presence of bone marrow mononuclear cells within the injected myocardium area. CONCLUSIONS: Intravenous bone marrow mononuclear cell injection was ineffective to target myocardium. Myocardial cell distribution following intracoronary injection did not depend on myocardial infarction presence, a factor that could be useful for cardiac cell therapy in patients with chronic heart failure of non-ischemic origin or with ischemic myocardium without myocardial infarction.

Developing cell therapy techniques for respiratory disease: intratracheal delivery of genetically engineered stem cells in a murine model of airway injury.

Interest has increased in the use of exogenous stem cells to optimize lung repair and serve as carriers of a therapeutic gene for genetic airway diseases such as cystic fibrosis. We investigated the survival and engraftment of exogenous stem cells after intratracheal injection, in a murine model of acute epithelial airway injury already used in gene therapy experiments on cystic fibrosis. Embryonic stem cells and mesenchymal stem cells were intratracheally injected 24 hr after 2% polidocanol administration, when epithelial airway injury was maximal. Stem cells were transfected with reporter genes immediately before administration. Reporter gene expression was analyzed in trachea-lungs and bronchoalveolar lavage, using nonfluorescence, quantitative, and sensitive methods. Enzyme-linked immunosorbent assay quantitative results showed that 0.4 to 5.5% of stem cells survived in the injured airway. Importantly, no stem cells survived in healthy airway or in the epithelial lining fluid. Using 5-bromo-4-chloro-3-indolyl-beta-d-galactopyranoside staining, transduced mesenchymal stem cells were detected in injured trachea and bronchi lumen. When the epithelium was spontaneously regenerated, the in vivo amount of engrafted mesenchymal stem cells from cell lines decreased dramatically. No stem cells from primary culture were located within the lungs at 7 days. This study demonstrated the feasibility of intratracheal cell delivery for airway diseases with acute epithelial injury.

Autologous myoblast transplantation after myocardial infarction increases the inducibility of ventricular arrhythmias.

BACKGROUND: Small scale clinical trials suggested the feasibility and the efficacy of autologous myoblast transplantation to improve ventricular function after myocardial infarction. However, these trials were hampered by unexpected episodes of life-threatening ventricular tachyarrhythmias (VT). We investigated cardiac electrical stability after myoblast transplantation to the myocardium. METHODS AND RESULTS: Seven days after coronary ligation, Wistar rats were randomized into 3 groups: a control group receiving no further treatment, a vehicle group injected with culture medium into the infarcted myocardium, and a myoblast group injected with autologous myoblasts. Holter monitoring did not discriminate the myoblast from the vehicle groups. Programmed Electrical Stimulation (PES) was performed to evaluate further a cardiac substrate for arrhythmia susceptibility. The occurrence of sustained VT during PES was similar in control and vehicle groups (5/17 and 4/19 rats, respectively; p=0.50). In contrast, 13/20 rats (65%) from the myoblast group showed at least one episode of sustained VT during PES (p<0.05 and p<0.005 versus control and vehicle groups). As a further control group, rats injected with autologous bone marrow mononuclear cells into the infarcted myocardium did not show increased susceptibility to PES. CONCLUSIONS: In an infarcted rat model, myoblast transplantation but not bone marrow mononuclear cells or myocardial injection per se induces electrical ventricular instability. Because ventricular arrhythmias are life-threatening disorders, we suggest that such preclinical evaluation should be conducted for any new source of cells to be injected into the myocardium.

Adenovirus-mediated gene transfer of superoxide dismutase and catalase decreases restenosis after balloon angioplasty.

BACKGROUND: Reactive oxygen species (ROS) production increases after injury and potentially contributes to restenosis after angioplasty. We therefore evaluated the effect of adenovirus-mediated gene transfer (Ad) of superoxide dismutase (SOD) and catalase (CAT) on ROS production and restenosis after balloon angioplasty. METHODS: O(2)(-) and H(2)O(2 )production was quantified in cultured cells after incubation with either LPS or CuSO(4). Angioplasty and gene transfer were performed in rabbit atherosclerotic iliac arteries. One artery was injected with AdSOD and AdCAT, while the contralateral artery was injected with an adenovirus carrying no transgene, and served as control. RESULTS: ROS production was significantly decreased after adenovirus-mediated gene transfer of SOD and CAT as compared with control. Treated arteries showed less restenosis (32 +/- 27 vs. 63 +/- 19%, p = 0.003) and less constrictive remodeling (1.2 +/- 0.3 vs. 0.9 +/- 0.2, p = 0.02) than control arteries. Arteries injected with AdSOD and AdCAT showed better vasoreactivity to acetylcholine (11 +/- 4 vs. -1 +/- 6%, p < 0.05), lower collagen density (43 +/- 16 vs. 53 +/- 23%, p = 0.03), and lower inflammatory cell infiltration (22 +/- 6 vs. 36 +/- 11%, p = 0.04) than control arteries. CONCLUSIONS: Our data suggest that adenovirus-mediated gene transfer of SOD and CAT reduced oxidative stress, restenosis, collagen accumulation, and inflammation and improved endothelial function after angioplasty.

Effect of adenovirus-mediated overexpression of decorin on metalloproteinases, tissue inhibitors of metalloproteinases and cytokines secretion by human gingival fibroblasts.

Decorin is a small leucine-rich proteoglycan that plays a role in control of cell proliferation, cell migration, collagen fibrillogenesis and modulation of the activity of TGF-beta. In the present study, we investigated the effects of decorin on the production of metalloproteinases (MMP-1, -2, -3, -9 and -13), tissue inhibitors of metalloproteinases (TIMP-1, -2) and cytokines (TGF-beta, IL-1beta, IL-4 and TNF-alpha). Decorin was overexpressed in cultured human gingival fibroblasts using adenovirus-mediated gene transfer. Decorin infection resulted in decreased protein levels of MMP-1 and MMP-3 whereas MMP-2 and TIMP-2 secretion was increased. MMP-9, MMP-13 and TIMP-1 were not affected by decorin infection. Cytokine measurements by ELISA showed that decorin overexpression reduced TGF-beta and IL-1beta. In contrast, IL-4 and TNF-alpha levels were markedly increased in decorin-infected cells. These results suggest that decorin could modulate the expression of certain metalloproteinases and their inhibitors, as well as the production of cytokines. Altogether, our data suggest that decorin might play a pivotal role in tissue remodeling by acting on the balance between extracellular matrix synthesis and degradation.