A Paper Synopsis

Numerous investigations have been made to learn how cell or gene therapy might be applied to cure conditions that affect cells. Cell and gene therapies have advanced, but their capacity to deliver cells to the desired organs has been limited. Dystrophin expression in the MDX mouse was studied by Gussoni (1999) and recovered by stem cell transplantation. The study involved an experiment in which bone marrow was transplanted into a mouse. The results of the experiment suggested that the delivery of therapeutic cells is crucial in the treatment of diseases like muscular dystrophy, and that the transplantation of non-similar cell populations using the bone marrow procedure will help. The present document is a summary of the report by Gussoni.

Findings from the study done by Gussoni suggested that cells obtained from various tissues and organs may be similar than earlier thought. Nine female mice were given an injection through the tail vein with male bone marrow cells to determine whether bone marrow from a different dystrophic gene could return the dystrophic expression within its expression. After 5 weeks all the test animals had hematopoietic cells from the male donor. 5 to 12 weeks after the transplantation the tibialis anterior muscles of the used animals were tested for dystrophy expression to detect male cells which were donor derived. 8 weeks after the transplantation only 1% of the muscle cells showed dystrophy but by the 12th week, about 10% of the muscle fibers in the animals showed positive male chromosomes on the myofibres (Gussoni, 1999).

The main aim of the study was to address the issue of cell determination of bone marrow cells that can produce muscle 8,9 that previous study had not been able to show. In this way, the main research question was “After bone marrow transplantation, Can highly purified hematopoietic stem cells give rise to dystrophic positive myofibers?” Nine female mice were injected with HSC cells taken from a male mouse. 5 to 8 weeks later the mice were dead and after a FISH test, the confirmation was that the donor cells completely reconstituted the female host cells (Gussoni, 1999). By analysis of serial secretions, the tibial anterior muscles were tested for dystrophin expression and also for the presence of male donor cells.

The results were that at 5 weeks only below one percent of the myofibres had expressed dystrophin. At 8 weeks only about 1% of the muscle fibers showed dystrophy. 12 weeks later dystrophin was recognized in around 4 % dystrophy. The cells were analyzed further and among the 39 pictured sections, some Y+ nuclei were found to be centrally located. Others were found to be peripherally located around the myofibres and others were joined to the myofibres of the host but their whereabouts were not known (Gussoni, 1999). In some cases, not more than one male donor cells were found after clusters of dystrophin positive were tested. This could be due to the fusion of Y+ cells to targeted cells or it could be also an inaccurate estimation of dystrophin positive fibers that are known of nuclei gotten from the donor (Meyer, 2009).

After looking further at the fibers, Gussoni only managed to explore and analyze a small portion of the fibers using FISH and immunohistochemistry; as such, Gussoni came to the conclusion that the FISH test cannot identify the 100% nuclei of the male. Though with time the number of donor cells decreases after the period after bone marrow transfusion increased which could be dystrophin of the donor increasing within time (Gussoni, 1999). As from other researches, hematopoietic purification of cells appears that they occur when some physical properties are the same with hematopoietic cells in different species like human beings (Meyer, 2009).

The next step in the study was to know whether this method may be used to extract putative stem cells from skeletal muscle and after extraction, the side population cells could hardly be recognized upon addition of verapril (Gussoni, 1999). The studied muscle SP cells were shown to be different from bone marrow SP and muscle MP cells. Muscle SP cells required 2.5 more times the dye used to purify the bone marrow cells than bone marrow SP. The cells were also different in shape as in during a vitro culture since muscle MP cells could easily be seen to have fully differentiated myoblasts while the SP cells form spherical shapes throughout (Gussoni, 1999).

The conclusion that is most practical from the study is that muscle SP cells seem to provide a systematic repair of muscles since they are transported through the vascular system. The method of stem cell transplantation could be used in the future to provide for levels of cell engraftments that would be useful clinically. The experiment has also helped in discovering more on properties of stem cells that are different and the capacity of them to reconstitute in different muscles (Gussoni, 1999). Another important finding was that the purification method, which had been previously used to remove hematopoietic cells, could be used to derive similar cells from the bone marrow. The results of the study also showed that there is some relation between cells from the bone marrow with cells from other tissues.

In conclusion, the study has helped find out that organ-specific cells may develop as a result of the normal development of the tissues. It has also been found that SP like cells can be found and isolated from different organs. All the bone marrow and stem cells that were given were administered intravenously into the tail veins of the mice.



References

Gussoni, E., Soneoka, Y., Strickland, C. D., Kunkel, L. M., & Mulligan, R. C. (1999). Dystrophin expression in the MDX mouse restored by stem cell transplantation, 401(September).

Meyer, U. (2009). Fundamentals of tissue engineering and regenerative medicine. Berlin: Springer.