Biointerventional cardiology: the future interface of interventional cardiovascular medicine and bioengineering

Stem cell therapy in heart diseases: a review of selected new perspectives, practical considerations and clinical applications

Degeneration of cardiac tissues is considered a major cause of mortality in the western world and is expected to be a greater problem in the forthcoming decades. Cardiac damage is associated with dysfunction and irreversible loss of cardiomyocytes. Stem cell therapy for ischemic heart failure is very promising approach in cardiovascular medicine. Initial trials have indicated the ability of cardiomyocytes to regenerate after myocardial injury. These preliminary trials aim to translate cardiac regeneration strategies into clinical practice. In spite of advances, current therapeutic strategies to ischemic heart failure remain very limited. Moreover, major obstacles still need to be solved before stem cell therapy can be fully applied. This review addresses the current state of research and experimental data regarding embryonic stem cells (ESCs), myoblast transplantation, histological and functional analysis of transplantation of co-cultured myoblasts and mesenchymal stem cells, as well as comparison between mononuclear and mesenchymal stem cells in a model of myocardium infarction. We also discuss how research with stem cell transplantation could translate to improvement of cardiac function.

Left Ventricular Functional Recovery with Percutaneous, Transvascular Direct Myocardial Delivery of Bone Marrow-Derived Cells

BACKGROUND

The potential for cellular cardiomyoplasty to provide functional left ventricular recovery in the chronically injured heart remains unclear.

METHODS

Yorkshire swine (n = 10; 35-50 kg) had anterolateral myocardial infarction (MI) induced by coil embolization of the left anterior descending artery. Approximately 5 weeks post-MI, a composite, intravascular ultrasound-guided catheter system (TransAccess) was used to deliver an autologous, labeled, bone marrow-derived cell sub-population (approximately 3 x 10(8) cells) or saline control (approximately 50 injections/arm) through coronary veins directly into infarct and peri-infarct myocardium. Two months post-transplant, the animals had blinded endocardial and epicardial left ventricular electrical scar mapping and biventricular electrical stimulation. Coronary angiography and quantitative biplane ventriculography were performed at baseline, transplant, and sacrifice time-points.

RESULTS

Robust, viable, predominantly desmin-negative cell grafts were demonstrated post-mortem in all treatment animals. Baseline and pre-transplant global and regional wall motion was similar between groups. The cell treatment group demonstrated functional recovery with a left ventricular ejection fraction of 38.1% at the time of transplant increasing to 48.5% (p = 0.005) at sacrifice, whereas the control arm was unchanged (38.0% vs 34.3%, respectively; p = NS). The regional improvement corresponded with a reduction in percentage of hypokinetic (52.1%-42.9%, p = 0.002) and percentage of akinetic (24.8%-17.7%, p = 0.04) segments in the cell-treated animals. Epicardial scar area was not different (37 cm2 vs 23 cm2, p = 0.37) between groups.

CONCLUSIONS

Percutaneous, transvascular, direct intramyocardial bone marrow cell transplantation is safe and feasible in chronically infarcted tissue. In this pilot study, cell therapy improved overall left ventricular systolic function by recruiting previously hypokinetic or akinetic myocardial tissue.

Autologous Skeletal Myoblasts for Myocardial Regeneration

We overview the current knowledge about the use of skeletal myoblasts in regeneration of infarcted myocardium. Myoblasts are attractive candidates for cell source for cardiomyoplasty in chronic postmyocardial injury as indicated by experimental and initial clinical experience. We also review the recent developments in skeletal myoblasts transplantation techniques with special attention to percutaneous transvenous approach to deliver therapeutic agents into myocardium from the lumen of coronary veins under intravascular guidance.

Percutaneous transvenous cellular cardiomyoplasty. A novel nonsurgical approach for myocardial cell transplantation

OBJECTIVES

The study evaluated a nonsurgical means of intramyocardial cell introduction using the coronary venous system for direct myocardial access and cell delivery.

BACKGROUND

Direct myocardial cell repopulation has been proposed as a potential method to treat heart failure.

METHODS

We harvested bone marrow from Yorkshire swine (n = 6; 50 to 60 kg), selected culture-flask adherent cells, labeled them with the gene for green fluorescence protein, expanded them in culture, and resuspended them in a collagen hydrogel. Working through the coronary sinus, a specialized catheter system was easily delivered to the anterior interventricular coronary vein. The composite catheter system (TransAccess) incorporates a phased-array ultrasound tip for guidance and a sheathed, extendable nitinol needle for transvascular myocardial access. A microinfusion (IntraLume) catheter was advanced through the needle, deep into remote myocardium, and the autologous cell-hydrogel suspension was injected into normal heart. Animals were sacrificed at days 0 (n = 2), 14 (n = 1, + 1 control/collagen biogel only), and 28 (n = 2), and the hearts were excised and examined.

RESULTS

We gained widespread intramyocardial access to the anterior, lateral, septal, apical, and inferior walls from the anterior interventicular coronary vein. No death, cardiac tamponade, ventricular arrhythmia, or other procedural complications occurred. Gross inspection demonstrated no evidence of myocardial perforation, and biogel/black tissue dye was well localized to sites corresponding to fluoroscopic landmarks for delivery. Histologic analysis demonstrated needle and microcatheter tracts and accurate cell-biogel delivery.

CONCLUSIONS

Percutaneous intramyocardial access is safe and feasible by a transvenous approach through the coronary venous system. The swine offers an opportunity to refine approaches used for cellular cardiomyoplasty.