- After a heart attack the dead muscle of the heart is replaced by scar tissue - stem cell can help form new muscle from the scar tissue
- Heart muscle called cardiomyocytes are being produced from scar tissue (fibroblasts) using different techniques
- These vary genetically according to the technique used to produce them
compared reprogrammed cardiomyocytes produced by two different techniques - the
iPSC-CMs and iCMs. They published their study in Cell Reports.
Following a heart attack, the muscle cells of the heart, referred to as cardiomyocytes, die in the affected area. The cells of the heart, like those of the brain, are unable to regenerate. This weakens the heart muscle which is then unable to carry out its pumping function efficiently and a large damaged area can result in heart failure.
In the recent years, attempts have been made to regenerate the heart cells, which can then be used to replace the damaged cardiac muscle. In addition, the muscle cells thus produced can be used for other purposes like disease modeling and drug screen. In disease modeling, a model of the heart muscle is created in the laboratory to study pathological processes associated with the disease. A drug screen that uses the cells from a patient could help to determine the drugs and dosage that would work best for that particular patient.
- The fibroblasts are first converted into induced pluripotent stem cells (iPSCs), an immature form of cells, which then differentiate into cardiomyocytes.
- Differences were observed in the expressed genes as well as a large number of noncoding RNAs in the cardiomyocytes produced by the different procedures.
- When the genes that were activated and not activated in the cells were compared, the iPSC cardiomyocytes (iPSC-CMs) were more similar to early embryonal cardiomyocytes with more active genes and a higher number of genes likely to be either activated or repressed. iCMs on the other hand, resembled adult cardiomyocytes more closely.
- The structure of the muscle cells was less organized and the contractility of the cells was less in the iPSC-CMs as compared to iCMs, reflecting the immaturity of the iPSC-CMs as compared to the iCMs.
- Longer culture times did improve the maturity of the iPSC-CMs but not as much as that of the iCMs.
- The cells differed in the genes responsible for metabolism. iPSC-CMs primarily expressed the glycolysis pathway genes, whereas iCMs primarily expressed the fatty acid oxidation genes.
- Yang Zhou, Li Wang, Ziqing Liu, Sahar Alimohamadi, Chaoying Yin, Jiandong Liu, Li Qian3,'Correspondence information about the author Li Qian. Comparative Gene Expression Analyses Reveal Distinct Molecular Signatures between Differentially Reprogrammed Cardiomyocytes. Cell Reports. DOI: http://dx.doi.org/10.1016/j.celrep.2017.09.005