Results: Immunofluorescence staining was positive against a-actin, desmin, and cTnT on MSCs in co-culture group with adult cardiomyocytes, positive against smooth muscle calponin and SM-a-actin on MSCs in co-culture group with SMCs. In contrast, no a-actin, desmin, and cTnT expression was observed in the indirect co-culture group and conditioned culture group; no smooth muscle calponin and SM-a-actin in the indirect co-culture group and conditioned culture group.
Conclusions: Direct cell-to-cell contact between MSC and adult cardiomyocyte or SMC, but not the soluble signaling molecules is obligatory in the differentiation of MSC into cardiomyocytes or SMC. D 2005 Elsevier Ireland Ltd. All rights reserved.
Keywords: Mesenchymal stem cell; Cardiomyocyte; Smooth muscle cell; Differentiation; Contact
Stem cell is one of the focuses of modern scientific research for its better plasticity . It can differentiate into many cell types, such as cardiomyocyte [2–7], neuron ,
hepatocyte , islet h-cell , in vivo and in vitro. For this reason, regeneration medicine became a potential therapy for degenerative diseases, such as myocardial infarction, diabetic mellitus, and Parkinson’s syndrome. The most important is to treat cardiovascular diseases, which are rapidly becoming the number one killer in the developing countries . However, embryonic stem cells have some restriction for the ethic problems, so tissue-specific stem cells, such as mesenchymal stem cell became the main engineering cell.
Many studies have showed that stem cells can differentiate into cardiomyocytes in vivo or in vitro  and then improve poorly functional heart. But little information about
the mechanism on how stem cells differentiate is known. The microenvironment plays a critical role in embryogenesis and organogenesis , and intercellular crosstalk
may be the governor in this process . There are several types of cells, such as cardiomyocytes, SMCs and some soluble chemical factors in myocardial infarction area. Can intercellular interaction or soluble chemical factors induce MSCs to acquire the phenotypical characteristics of cardiomyocytes or SMC?
0167-5273/$ – see front matter D 2005 Elsevier Ireland Ltd. All rights reserved.