In September I participated in a great scientific event. It was the ESAO 2013 conference in Glasgow –Scotland. I had an opportunity to present results of my recent work in form of speech entitled “Alginate and poly-L-lysine modified capsules as human cardiac stem cells delivery system for myocardial regeneration”.
The presentation concerned heart regeneration modern ideas. The endogenous repair of injured myocardium is limited process, therefore either cell replacement or recruitment into damaged heart area is required. The human cardiac stem cells (hCSC) therapy has been suggested as a novel approach to address myocardial regeneration. Unfortunately commonly applied methods of cell transfer are not sufficiently effective. The polymer alginate (ALG) or poly-L-lysine – alginate (PLL-ALG) microcapsules can be used to improve the efficiency of cell delivery and therapy. The aim of this study was to assess hemocompatybility and cytotoxic influence of capsules on the human cardiac stem cells growth and proliferation. The cytotoxic effect of alginate, poly-L-lysine-alginate microcapsules or their extracts on the primary hCSC culture conditions was examined by microscopic analysis of the death cells contribution. The viability and precentage of apoptotic cells was assessed after hCSC culture incubation with capsules by flow cytometric analysis of propidium iodide potential to intracellular penetration and anexin V, CD95, caspase-9 receptor expression. Changes in cell morphology were determined by microscopic observations after DAPI, phalloidin, anti-vimetnin staining and Shape Index (SI) evaluation. Moreover, the thrombogenicity of alginate, poly-L-lysine-alginate microcapsules in a few different dilutions was investigated by a flow cytometric analysis of platelets activation and aggregates formation. The effect of capsules or their extracts on lymphocytes activation was determined based on cytometric measurements of CD3, CD4, CD8, CD14, CD16, CD19, CD40, CD45RA, CD45RO and CD86 markers expression. Results of cytotoxicity studies showed significantly higher effect both of ALG capsules and extracts on the contribution of the death cells in comparison with PLL-ALG treated samples. It was found that capsules had no influence on cells viability. However, it was significant difference in caspase-9 expression between samples. The highest contribution of caspase-9 positive cells was noticed in PLL-ALG treated cultures. There was no significant difference in morphology and Shape Index values between control and samples treated by ALG or PLL-ALG capsules. It was no influence of capsule type on thrombogenic process. Dilution was significant only in case of aggregates formation. Samples treated with 100 times diluted PLL-ALG capsules indicated the highest aggregates contribution. It was found that capsule or extract type had no significant influence on lymphocyte activation. Results of performed studies showed that application of capsules is promising concept of myocardium regeneration based on paracrine action of hCSC, due to non-toxic effect on cardio-spheres, either lack of trombogenicity or potential to lymphocytes system activation.