Bio301: Stem cell production in bioreactor ( chemostat )

1. Bio301: Stem cell production in bioreactor(chemostat) 1.Author’s background 2.Executive Summary 3.Background 4.Article 1 5.Article 2 6.Comparative Analysis 7.Personal opinion 8.Appendix Name: Ling lu Qi, Rodney Student ID: 32140372

2. My name is Rodney Ling and I am currently pursuing a double major in Biotechnology and Molecular Biology. I believe the upcoming hit in the bioprocessing in chemostat would not only be limited to microorganism but also mammalian cells. It has ongoing research on the mammalian stem cell production in bioreactor for therapeutic purposes such as regenerative medicine or clinical advantages ( drug screening) It has grown my interest to look into stem cell production using chemostat as a form of mass production as production of stem cell with tissue engineering remove a lot of limitation in current therapeutic methods. Side thoughts => think about people who are dying off due to infunctional organs. If we could replace it with a synthetic organ which is viable, wouldn’t it prolong lifes of the severely ill patients or even new born child with defects? 1.Author’s background 2.Executive Summary 3.Background 4.Article 1 5.Article 2 6.Comparative Analysis 7.Personal opinion 8.Appendix Author’s background

3. The aim of this website is to determine the feasibility of human embryonic stem cell production in a chemostat. Since this is a novel idea, the comparison of 2 article was done based on stating the fundamentals of chemostat which cells proliferate infinitely when kept in an environment without restrain in growth. It was known that telomere shortening has shown aging in eukaryotic cells thus, by looking into telomere shortening would deduce the feasibility of infinite growth in embryonic stem cells. 1.Author’s background 2.Executive Summary 3.Background 4.Article 1 5.Article 2 6.Comparative Analysis 7.Personal opinion 8.Appendix Executive Summary

4. Chemostat production of cells has been widely used in microorganisms and it has not been tried with embryonic stem cell. Chemostat has shown higher production rate as comparative to batch culture which goes through the growth stages. Chemostat pushes the limit by keeping the growth rate at the exponential phase and cells proliferate infinitely showing immortality. It would be therapeutically useful in production of embryonic stem cell as synthetic human organs could be differentiated from embryonic stem cells with scaffolding. Mammalian cells has known to age due to telomere shortening in every cell division during DNA replication. The comparison between the 2 articles would show the possibility of growing embryonic stem cells in a chemostat to increase production of embryonic stem cells. Stirrer 1.Author’s background 2.Executive Summary 3.Background 4.Article 1 5.Article 2 6.Comparative Analysis 7.Personal opinion 8.Appendix Background

5. [2.Michal Amit,et al; 2000] Telomere shortens during each DNA replication in a eukaryotic cell has been the issue with culturing of eukaryotic cells. This article has shown telomere lengths to be stable between 8 and 12 kbof hESC 2 cloned cell line was performed and was found with one hSEC line at passage 57 cells had a telomere length of about 8 kb which increased to 13 kb at passage 143 with another hSEC line an initial decrease in telomere length followed by an increase to about 11 kb at passage 123. It has shown that the cells were able to regenerate the telomere by telomerase activity after shorting which was the issue with cell aging. The cultured hESC had survived approximately 300 population doublings, i.e., four to six times the life span of normal somatic cells, suggests that these cells are immortal. Based on this article, we could see that human embryonic cell line are immortal since they had the mechanism of self repair in the telomere. Therefore, it is possble to produce them in chemostat as their growth would be infinite. 1.Author’s background 2.Executive Summary 3.Background 4.Article 1 5.Article 2 6.Comparative Analysis 7.Personal opinion 8.Appendix Article 1

6. [Sharon Gerecht-Nir,et al , 2003] This article has shown a higher growth of hESC in slow turning lateral vessel (STLV) compared to a static culture. It has shown that STLV culture has a higher concentration of DNA and protein compared to static culture and a 3 fold more in cell count after 28 days.(Figure 1) It was also found that STLV culture shown mixing prevented agglomeration of the small hEBs, and thus in later culture times, necrosis was less pronounced in this system as from the third week, the viable cell concentration exceeded static cultures. LDH leakage was measured and static cultures, from the second week there was an increase in LDH activities in the medium. This correlated with the increased size of hEBs due to some agglomeration events which resulted in cell necrosis in the center whereas STLV-formed hEBs were mostly viable.(table 2) Based on this article, it is known that using bioreactor to culture embryonic stem cells has a higher biomass productivity as compared to static cultures. Since a batch culturing bioreactor could increase the productivity of embryonic stem cells, it is possible that a chemostat could increase the production rate of embryonic stem cells as compared to bioreactor. 1.Author’s background 2.Executive Summary 3.Background 4.Article 1 5.Article 2 6.Comparative Analysis 7.Personal opinion 8.Appendix Article 2

7. Based on the background, microorganism can proliferate infinitely in a chemostats. Mammalian cell line has shown senescence during proliferation due to shortening of telomere. Based on article 1, it is sound that embryonic cell line has shown no sign of senescence with telomerase activity to increase the length of telomere when it became shorten. Since article 1 has stated that embryonic cell line could proliferate infinitely, it will be possible to produce embryonic cell line with the methods of production of microorganism which means chemostat would be viable in production of embryonic cell line. In article 2, we could see that with using of bioreactor, which is non-continuous culturing, it could be seen that it increases the production of embryonic cell line by 3 fold as compared to normal petri dish subculturing. It can also be seen that with stiring of the culture, it prevents agglomeration to occur thus having smaller hEB compared to static culture. Static culture having a bigger hEB has shown necrosis in the middle of the hEB whereas STLV culture showed no sign of necrosis. Thus with the basis of all 2 article, it would be sound to state that growing embryonic stem cell in a chemostat would be feasible and would have a high productivity rate as compared to a bioreactor or static culture. 1.Author’s background 2.Executive Summary 3.Background 4.Article 1 5.Article 2 6.Comparative Analysis 7.Personal opinion 8.Appendix Comparison analysis.

8. From the articles, it can be seen that telomere shortening showing signs of senescence has no effect in human embryonic stem cell as there is self repairing mechanism of the telomere shortening. It has also been shown that with a bioreactor, it has produced 3 fold as compared to normal petri dish culture. I would find it interesting as how much more productivity can we get from a chemostats since based on bioreactor in batch has increased production in 3 fold more then I believe chemostat could push the limit higher by production of maybe 6 fold or even higher. It would also be a new break-through in the therapeutic methods as tissue engineering could produce differentiated organ and it has been seen that organs produced synthetically has shown viability in organ transplantation. 1.Author’s background 2.Executive Summary 3.Background 4.Article 1 5.Article 2 6.Comparative Analysis 7.Personal opinion 8.Appendix Personal opinion

9. 1.Sharon Gerecht-Nir, Smadar Cohen, Joseph Itskovitz-Eldor, 2003 “Bioreactor Cultivation Enhances the Efficiency of Human Embryoid Body (hEB) Formation and Differentiation” 2.Michal Amit, Melissa K. Carpenter, Margaret S. Inokuma, Choy-PikChiu,Charles P. Harris, Michelle A. Waknitz, Joseph Itskovitz-Eldor, and James A. Thomson,2000 “Clonally Derived Human Embryonic Stem Cell Lines Maintain Pluripotency and Proliferative Potential for Prolonged Periods of Culture” 3.http://stemcells.nih.gov/info/basics/pages/basics6.aspx 4.http://en.wikipedia.org/wiki/Telomerase 5.http://en.wikipedia.org/wiki/Telomere 1.Author’s background 2.Executive Summary 3.Background 4.Article 1 5.Article 2 6.Comparative Analysis 7.Personal opinion 8.Appendix Appendix