Research On Stem Cells For Regenerating Tissue Engineering Heart

OBJECTIVE:Tens of thousands of people are living with heart failureand waiting for a heart transplant every year.Heart transplantation remains the definitive treatment for end-stage heart failure,but the supply of donor organs is limited.A bioartificial heart is a theoretical alternative to donor heart for transplantationMETHODS:The research is covering three parts.The first part is the research of the heart decellularization scaffold and itsimmunogenicity.We perfuse the heart with SDS and triton-100,and got hear acellular matrix.To determine the level of immunological rejection,we detect IL-2,IL-10,TGF-? and IFN-yexpression in graft and recipient rats.The second part is about seed cells.To clarify whether physical contact or soluble chemicalfactors are dominant in the differentiation of MSCs,we used a semi-diffuse membrane culture system which only permits chemical factors to diffuse We also use azacytidine and medium(for cardiomyocytes culture)to induce MSC.We found that there was expression of desmin and cTnT on GFP labeled MSCs in different inducing methods.We obtain heart tube cell from the 11.5-day pregnant rat embryo.Immunocyte staining was employed to determine protein expression and transcription of hearttube cells.The third part is the construction of tissue engineering heart and detectionof its function.Immunocytochemistry and HE staining were used to analyze the cell station of engineering heart.The function of tissue engineering is detected by electrocardiogram.RESULTS:Antegrade coronary SDS perfusion yielded a fully decellularized construct.Histological evaluation revealed no remaining nuclei.IL-2,IL-10,TGF-?and IFN-y in the recipient animals showed that the immunogenicity of the decellularized scaffolds of different species was greatly reduced.For the seed cells,we isolate MSCsfrom rat.There is no clearly defined antigenic phenotype forMSCs.Some studies identified MSCs to express CD90(Thy-1),CD29,At the same time,typical hematopoietic antigens such as CD45,CD34,CD44,CD11b haven't been identified on MSCs.Our results were similar to known agreement.It's meant that those MSCs we isolated are a crowd of undifferentiated stem cells that are different from hematopoietic stem cells.Meanwhile,MSCs keep multi-differentiation potential.Our data suggested that cell-to-cell directcontact,no-direct contact and molecular chemistrycan induce MSC differentiate into myocardial cells.The heart tube cells can proliferate and have typical action potentials of cardiomyocytes.It maybe suits for tissue engineering heart construction.Finally,the tissue engineering heart formed contractile myocardium that performed stroke workCONCLUSIONS:Chronic coronary perfusion,pulsatile left ventricular load and synchronized left ventricular stimulation led to the formation of contractile myocardium that performed stroke work.PROSPECT:Tissue engineering promises to provide many new therapeutic options for individuals withCardiovascular disease.Future research endeavors should be aimed at designing more advanced 3D culturing systems(i.e.bioreactors),ameliorating stem celland biomimetic materials,establishing means to functionally integrate tissue-engineered constructs with host tissue,determining ways to increase vascularization in engineered constructs and defining the best cell sources and appropriate methods for guiding cell growth and differentiation.Culturing organ in vivo is another important aspect which we need to fous on.It maybe give us another vision to regenerate tissue engineering heart.