Jacqueline van der Zijden reports on how incubators are currently being used for the cultivation of vital cell lines.
A controlled, reliable incubation system can be one of the most valuable pieces of equipment in a laboratory. Having the ability to culture a healthy cell line can make the difference between successful and failed investigations and influence the results of ground-breaking research projects.
Since the birth of the first test tube baby in 1978, the frequency and success of IVF procedures has increased dramatically. A review of 10 reports by international groups estimated that across 74 countries, the number of babies born as a result of the IVF procedure went from around 90,000 to over 2 million between 1990 and 20121. Accounting for missing data, it is generally agreed that today there has been more than 5 million IVF births worldwide2.
Following this success, further improvement of assisted reproduction remains a widely pursued topic. The continuing development of easier methods has increased interest and introduced opportunities to make IVF more affordable, successful and available to the wider population.
The Karolinska Institute is the biggest medical university in Sweden and is responsible for some of this research. The prestigious Institute has a large stem cell programme containing many research groups, one of which is run by Professor Outi Hovatta. This project is investigating the maturation of human ovarian follicles and oocytes from cryostored human ovarian tissue. It is hoped that this technique can be employed when there are risks to implanting tissue directly back into the ovary of a woman who has lost her eggs, perhaps due to chemotherapy or genetic causes.
Successfully culturing oocytes from primodial follicles to full maturity is a long and delicate process and can be severely affected by their developing environment. Therefore, when undertaking this painstaking research the Institute is very dependant on the performance and reliability of its incubation systems. Recent advances in incubator technologies have meant that temperature and environmental control can be achieved.
There are twenty Panasonic MCO-5M incubators in the Karolinska Institute laboratories for reproductive research. These small, personal appliances are well suited for applications involving professional cell culturing, due to their precise CO2 and O2 level controls, reliable decontamination and temperature stability. This environmental control is vitally important in IVF research and was a major consideration for the Karolinska Institute when specifying their systems.
As with all cell cultivation, in order to culture mature oocytes, very precise conditions are required. For example, the temperature must remain at a constant 37˚C and reduced oxygen and carbon dioxide concentrations must be maintained, reflecting the natural in vivo conditions of the cells. Differentiations in these conditions can impact on cell metabolism and future viability, impacting on the success of potential IVF procedures.
At the Karolinska Institute, the optimum conditions are provided for each and every cell culture undergoing maturation, whether they are situated by the incubator door or at the back of the chamber. The uniformity in conditions is guaranteed by Panasonic’s patented Direct Heat and Air Jacket (Fig. 1), which ensures and maintains the required temperature of 37˚C by enclosing the chamber in high density foam insulation. In addition, gentle fan circulation reduces any temperature gradient throughout the chamber.
In order to provide physiological conditions for the cells in culture, the incubators also achieve stable gas concentrations through a combination of exclusive technologies. CO2 levels are maintained through a CO2 sensing system, which provide the necessary levels of accuracy (CO2 range between 0 to 20%).
A long-life zirconia oxygen sensor upholds the sub-ambient oxygen levels required by the Karolinska Institute. An automatic N2 cylinder switchover system is also included in this system, which switches from a primary to a secondary cylinder when recovery times exceed a given limit. In this way there are no large variations in gas concentration and no threat to the biological processes of the maturing ovarian follicles.
Prioritising cell security
Keeping these irreplaceable cells secure is a top priority at the Karolinska Institute. Many of the samples being cultured in the incubators are unique to the project and so it is crucial that any risk of damage or contamination is minimised as much as possible.
In the Panasonic system, a centralised microprocessor controller complete with alarm, programming, calibration and diagnostic protocols supervises all operations within the incubator. Internal conditions in the incubators are therefore constantly monitored and controlled. Should there ever be an issue, researchers are alerted immediately. The inclusion of multiple decontamination systems in the equipment itself further guarantees In vitro performance. Panasonic's combination of inCu saFe and SafeCell UV contamination control technology protects against both airborne and waterborne contaminants and prevents the growth of moulds, fungi and bacteria with constant germicidal protection. In this innovative application, where cells are unique, this provides additional reassurance to the team at the Karolinska Institute.
Professor Hovatta’s aim is to have this technique introduced into clinical settings, making IVF and assisted reproduction a viable option for women who have rreceived chemotherapy looking to become pregnant. By growing the cells in the stable, optimised environment provided by Panasonic incubators, primordial follicles can be cultured successfully into mature oocytes for IVF. The technique is already showing great success and although the cells have yet to reach the ideal size for implantation (120µm), ethics approval has already been given to move this research to the next stage.
“The cell environments created by the Panasonic incubators are very stable and well controlled,“ commented Professor Hovatta. “In our research, the cell lines are completely unique, so we cannot take any risks during their cultivation. By developing this technique, we are confident that we can demonstrate that the resulting oocytes and embryos are normal and healthy and eventually progress to clinical applications.”
References: 1. The number of babies born globally after treatment with the assisted reproductive technologies (ART) G.D. Adamson, M. Tabangin, M. Macaluso, J de Mouzon. Fertility and sterility. 1 September 2013; 2. 5 million babies born through IVF in past 35 years, researchers say. NBC News.14 October 2013 (www.nbcnews.com/health/5-million-babies-born-through-ivf-past-35-years-researchers-8C11390532)
Jacqueline van der Zijden is Product Manager at Panasonic Biomedical, Etten Leur, The Netherlands. www.panasonic-biomedical.co.uk