Heart failure is the primary cause of mortality and morbidity in the Western world. Although cell therapy has demonstrated improvement in cardiac function, these benefits are being attributed to the activation of paracrine factors, rather than the differentiation and integration of the transplanted cells into the host tissue. Based on this knowledge the focus of this thesis work was to deliver paracrine factors, and evaluate its effect on cardiac function.
Gene therapy has evolved as a promising option to deliver pro-angiogenic proteins to infarct zones, thus providing cardiac benefit. This study has identified a gene design without the use of viral vectors, to deliver transient, yet therapeutic levels of an angiogenic chemokine, Stromal-Derived-Cell-Factor-1 (SDF-1) in rodents with chronic heart failure, and has reported significant improvement in cardiac function. The use of Kozak sequences and translational enhancers helped boost gene expressions which could be accurately measured using bio-fluorescence imaging techniques. This improvement in gene expression was directly proportional to the improvement in cardiac function in rodents with chronic heart failure.
However effective plasmid delivery, via the systemic route, requires the encapsulation and targeting of the plasmid to infarct zones. An infarct-specific peptide was identified with the help of phage panning techniques and nanoparticles, formulated with poly lactide-co-glycolide (PLGA), were employed to encapsulate a fluorescent dye, 6-Coumarin (6C). Targeted and efficient delivery was achieved by tagging the surface of the nanoparticles with the targeting peptide. Another aspect of this study was to identify novel paracrine factors responsible for reverse ventricular remodeling, following the treatment of chronic heart failure with mesenchymal stem cell (MSC) therapy, using microarray analysis.
Overall, this study has identified the design and delivery technique for a therapeutic, cardiac-benefiting gene to the infarct zone, in rodents with heart failure. These results can be translated to a clinical setting, providing relief to patients with chronic heart failure. This study has also paved the way for future research in developing novel cardiac drugs, by identifying cardiac specific genes, responsible for reverse ventricular remodeling.