Recovery and functional activity of mononuclear bone marrow and peripheral blood cells after different cell isolation protocols used in clinical trials for cell therapy after acute myocardial infarction

The Impact of Centrifugal Force on Isolation of Bone Marrow Mononuclear Cells Using Density Gradient Centrifugation

BACKGROUND

Bone marrow mononuclear cells (BMMNCs) have great potential in bone regenerative therapy. The main method used today to obtain BMMNCs is Ficoll density gradient centrifugation. However, the centrifugal force for this isolation method is still suboptimal.

OBJECTIVES

To determine the optimal centrifugal force in Ficoll density gradient centrifugation of bone marrow (BM) to achieve high stem/progenitor cell content BMMNCs for regenerative therapy.

METHODS

BM was aspirated from nine minipigs and divided into three groups according to different centrifugal forces (200 g, 300 g and 400 g). Immediately after BMMNCs were obtained from each group by Ficoll density gradient centrifugation, residual red blood cell (RBC) level, nucleated cell counting, viability and flow cytometric analyses of apoptosis and reactive oxygen species (ROS) generation were measured. The phenotypic CD90 and colony formation analyses of BMMNCs of each group were performed as well. Bone marrow-derived mesenchymal stem cells (BMSCs) were harvested at passage 2, then morphology, cell phenotype, proliferation, adipogenic, chondrogenic and osteogenic lineage differentiation potential of BMSCs from each group were compared.

RESULTS

The 300 g centrifugal force was able to isolate BMMNCs from BM with the same efficiency as 400 g and provided significantly higher yields of CD90+ BMSCs and fibroblastic colony-forming units of BMSC (CFU-f(BMSC)), which is more crucial for the regenerative efficacy of BMMNCs. Meanwhile, 200 g hosted the most RBC contamination and minimum CFU-f (BMSC) yield, which will be disadvantageous for BMMNC-based cell therapy. As for in vitro cultured BMSCs which were isolated from BMMNCs by different centrifugal forces, no significant differences were found on morphology, cell proliferation rate, phenotypic marker, adipogenic, chondrogenic and osteogenic differentiation potential.

CONCLUSIONS

300 g may be the optimal centrifugal force when using Ficoll density gradient centrifugation to isolate BMMNCs for bone regenerative therapy.

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State of the art of stem cell therapy for ischaemic cardiomyopathy. Part 2

Ischemic cardiomyopathy is becoming a leading cause of morbidity and mortality in the whole world. Stem cell-based therapy is emerging as a promising option for treatment of ischemic cardiomyopathy. Several stem cell types, including cardiac-derived stem cells, bone marrow-derived stem cells, mesenchymal stem cells, skeletal myoblasts, CD34+ and CD133+ stem cells have been used in clinical trials. Clinical effects mostly depend on transdifferentiation and paracrine factors. One important issue is that a low survival and residential rate of transferred stem cells blocks the effective advances in cardiac improvement. Many other factors associated with the efficacy of cell replacement therapy for ischemic cardiomyopathy mainly including the route of delivery, the type and number of stem cell infusion, the timing of injection, patient's physical conditions, the particular microenvironment onto which the cells are delivered, and clinical conditions remain to be addressed. Here we provide an overview of modern methods of stem cell delivery, types of stem cells and discuss the current state of their therapeutic potential.

Bench-to-bedside optimization of mesenchymal stem cell isolation, processing, and expansion for in vivo administration

Aim: In this study, we aimed at identifying the optimal conditions for isolation, processing and expansion of mesenchymal stem cells (MSCs). Methods: Porcine bone marrow was obtained from either small- or large-volume bone marrow aspirate (BMA). Next, three BMA processing methods were compared. Finally, the best condition was selected from various culture parameters, including basal media, supplementation and seeding density. Results: Our results demonstrate that a small-volume BMA and direct plating yields significantly higher concentration of MSCs. Basal media supplementation with 10% platelet lysate and seeding density of 1000 cells/cm² can generate large numbers of multipotent MSCs with augmented function and low population doublings. Conclusion: This work provides guidance for preparation of robust MSCs for future clinical trials.

Single-step enrichment of basophils from human peripheral blood by a novel method using a Percoll density gradient

We have developed a novel continuous flow-through cell separation method using a Percoll density gradient. This method can continuously separate a large number of cells into five fractions according to their densities. To apply this method to the separation of basophils, Percoll density gradients were modified to improve basophil enrichment. When a set of Percoll density gradients was prepared (1.071, 1.075, 1.080, 1.084, and 1.090 g/mL) the basophils in a healthy volunteer were enriched by an average of 23.1 and 63.5% at Percoll densities of 1.075 (fraction 3) and 1.080 g/mL (fraction 4), respectively. On average, the yield of basophils was 1.66 × 10(5) cells in fraction 3 and 1.61 × 10(5) cells in fraction 4 from 9 mL of peripheral blood. The expression of CD203c (cluster of differentiation 203c) on separated basophils was upregulated by anti-immunoglobulin E stimulation similar to basophils in whole blood. Histamine release induced by calcium ionophore was also observed in the separated basophils. The present method will be useful for basophil enrichment since it preserves their function without using counterflow elutriation and immunological reagents, and this method will be effective as a preparative separation for cell purification by flow cytometry.

Tissue evacuated during joint replacement procedure as a source of mononuclear cells

Background

Different cell populations from bone marrow were used in various clinical trials for cardiac diseases during last decade. Four clinical studies are ongoing in our institution and enroll patients with cardiac diseases, coronary disease, type 2 diabetes, and osteoarthritis. The density gradient is used to separate bone marrow mononuclear cells. Joint replacement procedures were associated with significant loss of tissue. Usually, excess tissue as bone marrow, peripheral blood and fat are removed to clean operation site. The aim of this study is to prove whether removed tissue during joint replacement procedure can be considered as a significant source of mononuclear cells.

Methods

Excised tissue obtained during joint replacement procedure was collected by AutoLog system. Bone marrow tissue was collected by iliac crest puncture. Mononuclear cells from both sources were isolated by using Ficoll density gradient centrifugation. Flow cytometry was used to detect mononuclear cell, CD34+ population counts and cell viability. Tissue processing yields between the group of joint replacement and iliac crest puncture group were compared.

Results

Together, 34 bone marrow tissue processings were performed. On average, samples contained 46.31 ± 9.35 ml of bone marrow solution. Average cell yield in final product was 28.64 ± 9.35 × 10⁶ MNCs and 0.77 ± 1.51 × 10⁶ CD34+ population. In case of tissue removed during joint replacement nine processings were performed. On average samples contained 450 ± 157.69 ml of tissue solution. Average cell yield in final product was 76.67 ± 35.42 × 10⁶ MNCs and 1.33 ± 0.97 × 10⁶ CD34+ population.

Conclusions

Tissue processing analysis shows that tissue removed during joint replacement procedure can be assumed as a significant source of mononuclear cells. Methods used for bone marrow-derived mononuclear cell extraction can be applied to the excess tissue.

Suitability of small diagnostic peripheral-blood samples for cell-therapy studies

BACKGROUND AIMS

Primary hematopoietic stem and progenitor cells (HSPCs) are key components of cell-based therapies for blood disorders and are thus the authentic substrate for related research. We propose that ubiquitous small-volume diagnostic samples represent a readily available and as yet untapped resource of primary patient-derived cells for cell- and gene-therapy studies.

METHODS

In the present study we compare isolation and storage methods for HSPCs from normal and thalassemic small-volume blood samples, considering genotype, density-gradient versus lysis-based cell isolation and cryostorage media with different serum contents. Downstream analyses include viability, recovery, differentiation in semi-solid media and performance in liquid cultures and viral transductions.

RESULTS

We demonstrate that HSPCs isolated either by ammonium-chloride potassium (ACK)-based lysis or by gradient isolation are suitable for functional analyses in clonogenic assays, high-level HSPC expansion and efficient lentiviral transduction. For cryostorage of cells, gradient isolation is superior to ACK lysis, and cryostorage in freezing media containing 50% fetal bovine serum demonstrated good results across all tested criteria. For assays on freshly isolated cells, ACK lysis performed similar to, and for thalassemic samples better than, gradient isolation, at a fraction of the cost and hands-on time. All isolation and storage methods show considerable variation within sample groups, but this is particularly acute for density gradient isolation of thalassemic samples.

DISCUSSION

This study demonstrates the suitability of small-volume blood samples for storage and preclinical studies, opening up the research field of HSPC and gene therapy to any blood diagnostic laboratory with corresponding bioethics approval for experimental use of surplus material.

Quantitative Assessment of Optimal Bone Marrow Site for the Isolation of Porcine Mesenchymal Stem Cells

Background. One of the most plentiful sources for MSCs is the bone marrow; however, it is unknown whether MSC yield differs among different bone marrow sites. In this study, we quantified cellular yield and evaluated resident MSC population from five bone marrow sites in the porcine model. In addition, we assessed the feasibility of a commercially available platelet concentrator (Magellan® MAR01™ Arteriocyte Medical Systems, Hopkinton, MA) as a bedside stem cell concentration device. Methods. Analyses of bone marrow aspirate (BMA) and concentrated bone marrow aspirate (cBMA) included bone marrow volume, platelet and nucleated cell yield, colony-forming unit fibroblast (CFU-F) number, flow cytometry, and assessment of differentiation potential. Results. Following processing, the concentration of platelets and nucleated cells significantly increased but was not significantly different between sites. The iliac crest had significantly less bone marrow volume; however, it yielded significantly more CFUs compared to the other bone marrow sites. Culture-expanded cells from all tested sites expressed high levels of MSC surface markers and demonstrated adipogenic and osteogenic differentiation potential. Conclusions. All anatomical bone marrow sites contained MSCs, but the iliac crest was the most abundant source of MSCs. Additionally, the Magellan can function effectively as a bedside stem cell concentrator.

Enrichment and Molecular Analysis of Breast Cancer Disseminated Tumor Cells from Bone Marrow Using Microfiltration

Purpose

Molecular characterization of disseminated tumor cells (DTCs) in the bone marrow (BM) of breast cancer (BC) patients has been hindered by their rarity. To enrich for these cells using an antigen-independent methodology, we have evaluated a size-based microfiltration device in combination with several downstream biomarker assays.

Methods

BM aspirates were collected from healthy volunteers or BC patients. Healthy BM was mixed with a specified number of BC cells to calculate recovery and fold enrichment by microfiltration. Specimens were pre-filtered using a 70 μm mesh sieve and the effluent filtered through CellSieve microfilters. Captured cells were analyzed by immunocytochemistry (ICC), FISH for HER-2/neu gene amplification status, and RNA in situ hybridization (RISH). Cells eluted from the filter were used for RNA isolation and subsequent qRT-PCR analysis for DTC biomarker gene expression.

Results

Filtering an average of 14×10⁶ nucleated BM cells yielded approximately 17–21×10³ residual BM cells. In the BC cell spiking experiments, an average of 87% (range 84–92%) of tumor cells were recovered with approximately 170- to 400-fold enrichment. Captured BC cells from patients co-stained for cytokeratin and EpCAM, but not CD45 by ICC. RNA yields from 4 ml of patient BM after filtration averaged 135ng per 10 million BM cells filtered with an average RNA Integrity Number (RIN) of 5.3. DTC-associated gene expression was detected by both qRT-PCR and RISH in filtered spiked or BC patient specimens but, not in control filtered normal BM.

Conclusions

We have tested a microfiltration technique for enrichment of BM DTCs. DTC capture efficiency was shown to range from 84.3% to 92.1% with up to 400-fold enrichment using model BC cell lines. In patients, recovered DTCs can be identified and distinguished from normal BM cells using multiple antibody-, DNA-, and RNA-based biomarker assays.

The Clinical Status of Stem Cell Therapy for Ischemic Cardiomyopathy

Ischemic cardiomyopathy (ICM) is becoming a leading cause of morbidity and mortality in the whole world. Stem cell-based therapy is emerging as a promising option for treatment of ICM. Several stem cell types including cardiac-derived stem cells (CSCs), bone marrow-derived stem cells, mesenchymal stem cells (MSCs), skeletal myoblasts (SMs), and CD34(+) and CD 133(+) stem cells have been applied in clinical researches. The clinical effect produced by stem cell administration in ICM mainly depends on the transdifferentiation and paracrine effect. One important issue is that low survival and residential rate of transferred stem cells in the infracted myocardium blocks the effective advances in cardiac improvement. Many other factors associated with the efficacy of cell replacement therapy for ICM mainly including the route of delivery, the type and number of stem cell infusion, the timing of injection, patient's physical condition, the particular microenvironment onto which the cells are delivered, and clinical condition remain to be addressed. Here we provide an overview of the pros and cons of these transferred cells and discuss the current state of their therapeutic potential. We believe that stem cell translation will be an ideal option for patients following ischemic heart disease in the future.

Benchtop technologies for circulating tumor cells separation based on biophysical properties

Circulating tumor cells (CTCs) are tumor cells that have detached from primary tumor site and are transported via the circulation system. The importance of CTCs as prognostic biomarker is leveraged when multiple studies found that patient with cutoff of 5 CTCs per 7.5 mL blood has poor survival rate. Despite its clinical relevance, the isolation and characterization of CTCs can be quite challenging due to their large morphological variability and the rare presence of CTCs within the blood. Numerous methods have been employed and discussed in the literature for CTCs separation. In this paper, we will focus on label free CTCs isolation methods, in which the biophysical and biomechanical properties of cells (e.g., size, deformability, and electricity) are exploited for CTCs detection. To assess the present state of various isolation methods, key performance metrics such as capture efficiency, cell viability, and throughput will be reported. Finally, we discuss the challenges and future perspectives of CTC isolation technologies.

Stem cells for cardiac repair: problems and possibilities

Ischemic heart disease is a major cause of death throughout the world. In order to limit myocardial damage and possibly generate new myocardium, stem cells are currently being injected into patients with ischemic heart disease. Three major patient investigations, The LateTIME, the TIME and the Swiss Myocardial Infarction trials, have recently addressed the questions of whether progenitor cells from unfractionated bone marrow mononuclear cells limit myocardial damage and what the optimal time to inject these cells after acute myocardial infarctions (AMIs) is. In each of these trials, there were no significant differences between treated and control patients when bone marrow cells were administered 5-7 days or 2-3 weeks after AMIs. Nevertheless, these investigations provide important information regarding clinical trial designs. Patients with AMIs in these trials were treated with percutaneous coronary intervention within a median of 4-5 h after the onset of chest pain. Thereafter, all patients received guideline-guided optimal medical therapy. Consequently, the sizes of AMIs were significantly limited. In patients with small AMIs and near-normal left ventricular ejection fractions, progenitor cells are least effective. However, these trials do question whether autologous bone marrow mononuclear cells are the optimal cells for myocardial repair owing to low numbers of progenitor cells in bone marrow aspirates and the significant variability in potency and efficacy of these cells in patients with chronic multisystem diseases. In contrast, the SCIPIO and the CAUDUCEUS trials examined cardiac progenitor cells in patients with ischemic cardiomyopathies. These trials reported over 1-2 years that cardiac progenitor cells produced significant improvements in left ventricular contractility due to 12-24 g decreases in myocardial scars and 18-23 g increases in viable myocardial muscle. However, caution must be exercised in the interpretation of these studies due to the small numbers of highly selected patients and intra- and inter-observer variability in infarct size measurements. Anatomical and histological examinations of large numbers of patients treated with these cells are necessary to confirm significant generation of myocytes and decreases in infarct size and fibrosis.

Qualifying stem cell sources: how to overcome potential pitfalls in regenerative medicine?

Regenerative medicine aims to replace lost cells and to restore damaged tissues and organs by either tissue-engineering approaches or stimulation of endogenous processes. Due to their biological properties, stem cells promise to be an effective source for such strategies. Especially adult multipotent stem cells (ASCs) are believed to be applicable in a broad range of therapies for the treatment of multifactorial diseases or age-related degeneration, although the molecular and cellular mechanisms underlying their regenerative function are often hardly described. Moreover, in some demanding clinical situations their efficiency remains limited. Thus, a basic understanding of ASCs regenerative function, their complex interplay with their microenvironment and how compromising conditions interfere with their efficiency is mandatory for any regenerative strategy. Concerning this matter, the impact of patient-specific constraints are often underestimated in research projects and their influence on the study results disregarded. Thus, researchers are urgently depending on well-characterized tissue samples or cells that are connected with corresponding donor information, such as secondary diseases, medication. Here, we outline principle pitfalls during experimental studies using human samples, and describe a potential strategy to overcome these challenges by establishing a core unit for cell and tissue harvesting. This facility aims to bridge the gap between clinic and research laboratories by the provision of a direct link to the clinical operating theatres. Such a strategy clearly supports basic and clinical research in the conduct of their studies and supplies highly characterized human samples together with the corresponding donor information.

Density gradient centrifugation compromises bone marrow mononuclear cell yield

Bone marrow mononuclear cells (BMNCs) are widely used in regenerative medicine, but recent data suggests that the isolation of BMNCs by commonly used Ficoll-Paque density gradient centrifugation (DGC) causes significant cell loss and influences graft function. The objective of this study was to determine in an animal study whether and how Ficoll-Paque DGC affects the yield and composition of BMNCs compared to alternative isolation methods such as adjusted Percoll DGC or immunomagnetic separation of polymorphonuclear cells (PMNs). Each isolation procedure was confounded by a significant loss of BMNCs that was maximal after Ficoll-Paque DGC, moderate after adjusted Percoll DGC and least after immunomagnetic PMN depletion (25.6±5.8%, 51.5±2.3 and 72.3±6.7% recovery of total BMNCs in lysed bone marrow). Interestingly, proportions of BMNC subpopulations resembled those of lysed bone marrow indicating symmetric BMNC loss independent from the isolation protocol. Hematopoietic stem cell (HSC) content, determined by colony-forming units for granulocytes-macrophages (CFU-GM), was significantly reduced after Ficoll-Paque DGC compared to Percoll DGC and immunomagnetic PMN depletion. Finally, in a proof-of-concept study, we successfully applied the protocol for BMNC isolation by immunodepletion to fresh human bone marrow aspirates. Our findings indicate that the common method to isolate BMNCs in both preclinical and clinical research can be considerably improved by replacing Ficoll-Paque DGC with adapted Percoll DGC, or particularly by immunodepletion of PMNs.

A proinflammatory monocyte response is associated with myocardial injury and impaired functional outcome in patients with ST-segment elevation myocardial infarction: monocytes and myocardial infarction

BACKGROUND

In patients with ST-segment elevation myocardial infarction (STEMI), the importance of a well-balanced inflammatory reaction has been recognized for years. Monocytes play essential roles in regulating inflammation. Hence, we investigated the association between inflammatory characteristics of monocytes and myocardial injury and functional outcome in patients with STEMI.

METHODS

Using flow cytometry, the levels of classical (CD14(++)CD62L(+)) and nonclassical (CD14(+)CD62L(-)) monocytes were analyzed in peripheral blood in 58 patients with STEMI at a median of 5 days (4-6 days) after primary percutaneous coronary intervention. In addition, the monocytic expression of several surface molecules and formation of monocyte-platelet complexes were measured. All patients underwent cardiovascular magnetic resonance imaging at baseline and 4-month follow-up.

RESULTS

At baseline, patients with high levels of classical monocytes had impaired left ventricular (LV) ejection fraction (P = .002), larger infarct size (P = .001), and, often, presence of microvascular obstruction (P = .003). At follow-up, high levels of classical monocytes were negatively associated with the regional systolic LV function independent of the transmural extent of infarction. In contrast, positive associations for the levels of nonclassical monocytes were observed. Finally, up-regulation of macrophage 1 by blood monocytes and increased formation of monocyte-platelet complexes were associated with enhanced myocardial injury at baseline and impaired LV function at follow-up.

CONCLUSIONS

This study shows an association between a proinflammatory monocyte response, characterized by high levels of classical monocytes, and severe myocardial injury and poor functional outcome after STEMI. Future studies are required to investigate the biologic nature of this association and therapeutic implications.

Effect of intracoronary delivery of autologous bone marrow mononuclear cells 2 to 3 weeks following acute myocardial infarction on left ventricular function: the LateTIME randomized trial

CONTEXT

Clinical trial results suggest that intracoronary delivery of autologous bone marrow mononuclear cells (BMCs) may improve left ventricular (LV) function when administered within the first week following myocardial infarction (MI). However, because a substantial number of patients may not present for early cell delivery, the efficacy of autologous BMC delivery 2 to 3 weeks post-MI warrants investigation.

OBJECTIVE

To determine if intracoronary delivery of autologous BMCs improves global and regional LV function when delivered 2 to 3 weeks following first MI.

DESIGN, SETTING, AND PATIENTS

A randomized, double-blind, placebo-controlled trial (LateTIME) of the National Heart, Lung, and Blood Institute-sponsored Cardiovascular Cell Therapy Research Network of 87 patients with significant LV dysfunction (LV ejection fraction [LVEF] ≤45%) following successful primary percutaneous coronary intervention (PCI) between July 8, 2008, and February 28, 2011.

INTERVENTIONS

Intracoronary infusion of 150 × 10(6) autologous BMCs (total nucleated cells) or placebo (BMC:placebo, 2:1) was performed within 12 hours of bone marrow aspiration after local automated cell processing.

MAIN OUTCOME MEASURES

Changes in global (LVEF) and regional (wall motion) LV function in the infarct and border zone between baseline and 6 months, measured by cardiac magnetic resonance imaging. Secondary end points included changes in LV volumes and infarct size.

RESULTS

A total of 87 patients were randomized (mean [SD] age, 57 [11] years; 83% men). Harvesting, processing, and intracoronary delivery of BMCs in this setting was feasible. Change between baseline and 6 months in the BMC group vs placebo for mean LVEF (48.7% to 49.2% vs 45.3% to 48.8%; between-group mean difference, -3.00; 95% CI, -7.05 to 0.95), wall motion in the infarct zone (6.2 to 6.5 mm vs 4.9 to 5.9 mm; between-group mean difference, -0.70; 95% CI, -2.78 to 1.34), and wall motion in the border zone (16.0 to 16.6 mm vs 16.1 to 19.3 mm; between-group mean difference, -2.60; 95% CI, -6.03 to 0.77) were not statistically significant. No significant change in LV volumes and infarct volumes was observed; both groups decreased by a similar amount at 6 months vs baseline.

CONCLUSION

Among patients with MI and LV dysfunction following reperfusion with PCI, intracoronary infusion of autologous BMCs vs intracoronary placebo infusion, 2 to 3 weeks after PCI, did not improve global or regional function at 6 months.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00684060.

Intracoronary infusion of mononuclear cells from bone marrow or peripheral blood compared with standard therapy in patients after acute myocardial infarction treated by primary percutaneous coronary intervention: results of the randomized controlled HEBE trial

AIMS

Previous trials that investigated cell therapy as an adjunctive therapy after acute myocardial infarction (AMI) have shown conflicting results. We designed a randomized controlled trial to determine the effect of intracoronary infusion of mononuclear cells from bone marrow (BM) or peripheral blood in patients with AMI.

METHODS AND RESULTS

In a multicentre trial, 200 patients with large first AMI treated with primary percutaneous coronary intervention were randomly assigned to either intracoronary infusion of mononuclear BM cells (n = 69), mononuclear peripheral blood cells (n = 66), or standard therapy (without placebo infusion) (n = 65). Mononuclear cells were delivered intracoronary between 3 and 8 days after AMI. Regional and global left ventricular myocardial function and volumes were assessed by magnetic resonance imaging before randomization and at 4 months, and clinical events were reported. The primary endpoint of the percentage of dysfunctional left ventricular segments that improved during follow-up did not differ significantly between either of the treatment groups and control: 38.6 ± 24.7% in the BM group, 36.8 ± 20.9% in the peripheral blood group, and 42.4 ± 18.7% in the control group (P = 0.33 and P = 0.14). Improvement of left ventricular ejection fraction was 3.8 ± 7.4% in the BM group, 4.2 ± 6.2% in the peripheral blood group when compared with 4.0 ± 5.8% in the control group (P = 0.94 and P = 0.90). Furthermore, the three groups did not differ significantly in changes in left ventricular volumes, mass, and infarct size and had similar rates of clinical events.

CONCLUSION

Intracoronary infusion of mononuclear cells from BM or peripheral blood following AMI does not improve regional or global systolic myocardial function in the HEBE trial.

REGISTRATION

The Netherlands Trial Register #NTR166 (www.trialregister.nl) and the International Standard Randomised Controlled Trial, #ISRCTN95796863 (http://isrctn.org).

Left ventricular systolic and diastolic function improve after acute myocardial infarction treated with acute percutaneous coronary intervention, but are not influenced by intracoronary injection of autologous mononuclear bone marrow cells: a 3 year serial echocardiographic sub-study of the randomized-controlled ASTAMI study

AIMS

To clarify long-term changes in global, regional, and diastolic left ventricular (LV) function after intracoronary injection of autologous mononuclear bone marrow cells (mBMCs) in acute myocardial infarction (AMI).

METHODS AND RESULTS

In the Autologous Stem cell Transplantation in Acute Myocardial Infarction (ASTAMI) study, 100 patients with anterior ST-elevation myocardial infarction and percutaneous coronary intervention on the left anterior descending artery (LAD) were randomized to receive intracoronary injection of mBMCs or not. Transthoracic echocardiography was performed at baseline, 3, 6, 12 months, and 3 years. Regional LV function was assessed by two-dimensional speckle-tracking echocardiography. From baseline to 3 years, LV ejection fraction changed from 45.7 to 47.5% in the mBMC group, and from 46.9 to 46.8% in the control group (P = 0.87 for difference in change over time between groups). Longitudinal strain in the LAD territory improved from -9.7 to -12.2% in the mBMC group and from -9.9 to -12.8% in the control group (P = 0.45). E/e' decreased from 14.7 to 12.9 in the mBMC group and from 14.8 to 11.9 in the control group (P = 0.31). There were no significant differences between groups in change of LV volumes, global systolic function, regional function, or diastolic function during 3 years follow-up.

CONCLUSION

No differences between groups indicating beneficial effect of intracoronary mBMC injection could be identified. Both groups in ASTAMI experienced improvement of global, regional, and diastolic LV function after 3-6 months, with effects sustained at 3 years.

Oxygen and oxygenation in stem-cell therapy for myocardial infarction

Myocardial infarction (MI) is caused by deprivation of oxygen and nutrients to the cardiac tissue due to blockade of coronary artery. It is a major contributor to chronic heart disease, a leading cause of mortality in the modern world. Oxygen is required to meet the constant energy demands for heart contractility, and also plays an important role in the regulation of heart function. However, reoxygenation of the ischemic myocardium upon restoration of blood flow may lead to further injury. Controlled oxygen delivery during reperfusion has been advocated to prevent this consequence. Monitoring the myocardial oxygen concentration would play a vital role in understanding the pathological changes in the ischemic heart following myocardial infarction. During the last two decades, several new techniques have become available to monitor myocardial oxygen concentration in vivo. Electron paramagnetic resonance (EPR) oximetry would appear to be the most promising and reliable of these techniques. EPR utilizes crystalline probes which yield a single sharp line, the width of which is highly sensitive to oxygen tension. Decreased oxygen tension results in a sharpening of the EPR spectrum, while an increase results in widening. In our recent studies, we have used EPR oximetry as a valuable tool to monitor myocardial oxygenation for several applications like ischemia-reperfusion injury, stem-cell therapy and hyperbaric oxygen therapy. The results obtained from these studies have demonstrated the importance of tissue oxygen in the application of stem-cell therapy to treat ischemic heart tissues. These results have been summarized in this review article.

Bone marrow cell therapy after acute myocardial infarction: the HEBE trial in perspective, first results

During the last decennium, the role of bone marrow mononuclear cells (BMMC) has been underscored in the healing process after acute myocardial infarction (AMI). Although these cells improve left ventricular recovery after AMI in experimental studies, results from large-scale randomised trials investigating BMMC therapy in patients with AMI have shown contradictory results. To address this issue the HEBE study was designed, a multicentre, randomised trial, evaluating the effects of intracoronary infusion of BMMCs and the effects of intracoronary infusion of peripheral blood mononuclear cells after primary percutaneous coronary intervention. The primary endpoint of the HEBE trial is the change in regional myocardial function in dysfunctional segments at four months relative to baseline, based on segmental analysis as measured by magnetic resonance imaging. The results from the HEBE trial will provide detailed information about the effects of intracoronary BMMC therapy on post-infarct left ventricular recovery. In addition, further analysis of the data and material obtained may provide important mechanistic insights into the contribution of BMMCs to natural recovery from AMI as well as the response to cell therapy. This may significantly contribute to the development of improved cell-based therapies, aiming at optimising post-infarct recovery and preventing heart failure. (Neth Heart J 2008;16:436-9.).