Adult stem cells play an increasingly important role for medical applications. In the field of cell therapies, our working group has focused on enabling the utilization of adult stem cells for industrial applications in the health care sector. In fact, our working group has initially been describing the pluripotent differentiation capacity of human sweat gland-derived stem cells (SGSCs), which marked the sweat gland as a new source of human stem cells.
The undisputable advantages of SGSCs are the fact that they may easily be accessed, as well as their ethical innocuousness. In animal experiments, SGSCs were shown to exert a positive effect on wound healing, which was closely linked to an accelerated formation of new blood vessels (revascularization) in animals undergoing stem cell therapy. This may further imply applicability of SGSCs in treating ischemic diseases (as seen for example after a heart attack), with the aim to improve local revascularization. In order to eventually make sweat gland-derived stem cells available for clinical applications, harvest, propagation and subsequent storage of stem cells will need to be performed according to GMP guidelines. Thus, it will be necessary to extensively automate cell isolation and handling, as well as to standardize documentation procedures. Initial attempts at process adaptation have shown very promising results. Next, the working group is concerned with establishing an in situ sweat gland test system for pre-clinical testing of for example cosmetics and chemicals.
Such in vitro test system will further gain in importance, as new legislation is increasingly calling for feasible alternatives to animal testing.
The working group’s portfolio of in vitro test systems does also span into the area cardiac test systems. A setup of spontaneously contracting aggregates from the rainbow trout (SCCs) with multi-electrode arrays (MEAs) has already been pharmacologically characterized and was found suitable for detecting pro-arrhythmic substances. Latest studies have shown that this system may also be used for experiments performed on cardiac muscle cells affected by ischemia. Here, the typical human pathophysiology could also be demonstrated. Lastly, experiments performed under culture conditions involving the anesthetic isoflurane indicated a possible pharmacological modulation of SCCs under hypoxia. In future studies, the characterization of additional substances in the SCC setup will also be of interest to broaden the spectrum of potential applications for cardiac research.
Another focus area of this working group is concerned with the colonization of solid implants. In order to mitigate the risk of an adverse reaction directed against the implant, autologous human stem cells can be used to coat the outer surface area of a solid implant, prior to introducing it into the patient’s body. In an animal study performed with biologically coated brain probes, the advantage of disguising implants by covering them in stem cells could already be demonstrated. Further, especially also in the area of peripheral nerve regeneration, positive effects have been obtained by colonizing nerve tubes with stem cells in vitro. Here, it has been shown that stem cells are able to promote regeneration in nerve cell cultures.
Novel cell labeling methods are needed for improved and simplified tracing of stem cells in animals and tissue models. The particular challenge lies in developing a technique that does not influence the cells themselves, while reliably enabling cell tracking over prolonged periods of time. Here, a feasible solution could be electroporation of adherent cells. Compared to other established methods, electroporation is particularly gentle on cells, since the technique does not require cell detachment prior to treatment.