Screening of various tissues reported to harbor Oct4 expressing stem cells, such as heart and bone marrow, did not detect GFP+ cells in these tissues, although large cell numbers from each organ were analyzed (Table 1).
Stem cells are capable of self-renewal, that is, they can be continuously cultured in an undifferentiated stage, giving rise to more specialized cells such as heart, liver, bone marrow, blood vessels, pancreatic islets, and nerve cells upon addition or removal of certain growth factors [Fig. 11, reviewed in (Hoffman and Merrill 2007)].
Sox4 has been shown to be functionally involved in development of a wide range of tissues and cells, such as heart, B cells, reproductive system and central nervous system [ 26].
Consequently, while having an important role in the clearance of virus in infected heart tissue, virus-specific immune cells such as T and B cells may at the same time lead to increased tissue damage and burden for the host.
This is supported by the evidence that tissues composed of postmitotic cells such as the heart and brain show the most pronounced age-related changes [ 4, 5], whereas tissues with constantly proliferating cell populations such as the intestinal epithelium show only minor changes with age [ 6].
Moreover, tissues based predominantly (or to a high grade) on muscle cells such as (skeletal) muscle, heart (i.e. cardiac muscle) and trachea (which contains smooth muscular fibres) form a cluster based on the consolidated gene lists.
Increased levels of GSH are also observed in normal cells such as neurons, lung cells, heart cells, and blood vessel cells [ 31].
By treating stem cells with different chemicals they can be transformed into specialised cells such as those that make up heart muscle, brain, pancreas and other organs.
Since CNTs are electrically conductive, there is a huge potential for the manipulation of MSCs differentiation pathways to create electroactive cells such as those found in the heart.
