The maintenance of stem cell lines

Pluripotent cells (PSC’s) are taken from adult tissue or embryonic cells, these can also be induced, known as iPSC’s. This is when the pluripotent stem cell are genetically modified to be reprogrammed. I undertook some work experience at the Sheffield Institute of Translational Neuroscience Lab, which researches Parkinson’s disease, looking at both drug discovery and how the neurodegenerative disease manifests and progresses. Within the research a big task is maintaining different cell lines for future experiments on fibroblasts, induced neural progenitor cells (iNPC’s), astrocytes and neurons; to complete this, cells must be fed with nutritional media to help them grow and split when their is overcrowding in the dish. A stem cell should have the capability of infinite self renewal and differentiation, however in the lab there was a limit for how many times this could be conducted to prevent stress and harm to that cell line. The number of times the cells are split are called ‘passages,’ there was a rough limit of 15 passages per cell line. To ensure continuation of the line for the future, a spare dish is always kept frozen from the splitting process. Some cells used in the lab are brought in already modified for experimentation but other cells needed to be reprogrammed and grown in the lab, this aspect I got to observe during my visit for neuron cells. This entailed harvesting fibroblasts from the skin of a Parkinson patients and control patients with wild type cells which are exposed to a virus. The virus alters the genetic makeup of this cell to allow for differentiation into iNPC’s and eventually into neurons. This process can take anywhere between 2 weeks and 8 months to occur.

The picture on the LHS shows imaging of a stained Fibroblast, this is how the cells will look at start of the reprogramming process. The picture of the RHS shows a view down the microscope of neuronal cells, this is how they should look once reprogramming is complete, new cell lines can be taken and grown from this. Note: if the neuronal cells are taken from a Parkinsons patient they will be induced dopaminergic neuronal cells.

The legality…

There are legal implications with the use of stem cells in the UK, this varies from country to country, whereby scientists need to obtain permission from the governing body, ‘Human Fertilisation and Embryology Authority’ (HFEA) in order to use them. Lawyers, Clinicians, Scientists and Ethicists will determine if the use of that stem cell line is appropriate or not, if granted, regulations require these cells to be stored in the Stem Cell Bank. This bank enables all cells to be overseen, and allows researchers to use existing stem cells if given approval. Here is a link to the UK Government website explaining in detail the protocols put in place in the UK with regards to stem cells.

Ethical dilemmas…

There are many ethical dilemmas surrounding iPSC’s and the regulation of them. iPSC’s are very powerful having the ability to be taken as a fibroblast from the skin and reprogrammed into any cell type including, an egg or a sperm cell, these have been used to create mouse embryos which can develop into fully grown mice. This raises many questions including the implications of this experiment if it was to be conducted on humans in the future, the ownership of the cells – do they belong to the researcher or the donor? Should iPSC’s be used over embryonic stem cells?  Debates are still occuring to determine answers for these questions and come up with a sytem for monitoring embryonic stem cells and induced pluripotent stem cells looking at the benefits and challenges which come with each.

Accreditation:

Hirai, Takamasa, et al. “Country-Specific Regulation and International Standardization of Cell-Based Therapeutic Products Derived from Pluripotent Stem Cells.” Stem Cell Reports, vol. 18, no. 8, 1 Aug. 2023, pp. 1573–1591, www.ncbi.nlm.nih.gov/pmc/articles/PMC10444560/, https://doi.org/10.1016/j.stemcr.2023.05.003.

“Ethics.” The University of Edinburgh, 2 Aug. 2021, www.ed.ac.uk/regenerative-medicine/about/ethics.

“Sheffield Institute for Translational Neuroscience.” Www.sheffield.ac.uk, 10 May 2023, www.sheffield.ac.uk/sitran. Accessed 8 Mar. 2024.