Producing stem cells has always been a convoluted process. That’s why the discovery of key transcriptional networks are helping to pave the way for new culturing methods and further advancements in the field of cell therapy (see also,Pluripotent Stem Cells – What we know today) [1].
Producing stem cells has always been a convoluted process. That's why the discovery of key transcriptional networks are helping to pave the way for new culturing methods and further advancements in the field of cell therapy (see also,Pluripotent Stem Cells What we know today) [1]. According to the Journal of Molecular Endocrinology, these new mechanisms are fundamentally reforming the in vitro strategies currently used to generate and sustain iPS cells in culture [2]. Several methods have already been developed. The process roughly goes like this: take almost any differentiated cell, induce pluripotency, and you have a stem cell. Then, maintain and proliferate the stem cell line until there are enough cells to be used therapeutically. Since the success of cell therapy, in many ways, hinges upon the cultivation of hundreds of millions of SCs per patient, developments like these are allowing researchers to produce induced pluripotent stem cells (iPS cells) in greater supply and variety.
Stem Cell Treatments for Alzheimer's Disease
Stem cells are the only cells to divide throughout life and likely are the main cells to age through time. The most widely held view is that as stem cells age and divide they tend to accumulate DNA mutations and pass on any such epigenetic events to their descendants. Since these cells go on to support organ-specific tissues, it stands to reason that the organism itself will feel the consequences of aging [3].
Another symptom associated with aging is the loss of neurons in the brain, a burden shared by Alzheimer's patients. Alzheimer's disease is a progressive neural degenerate disorder that disrupts normal brain function such as, memory, communication, and judgement. Previous experiments have shown that various factors in the blood of old mice can impair the cognitive function in young mice. However, a new collaborative study led by researchers at Stanford and the University of California, San Francisco suggest that factors in the blood of young mice can reverse learning and memory impairments in old mice by improving the neuron function of the brain [4].
Researcher and study author Tony Wyss-Coray of Stanford said in a recent news release, This [research] could have been done 20 years ago. You don't need to know anything about how the brain works. You just give an old mouse young blood and see if the animal is smarter than before. It's just that nobody did it. He also said that treating the big-picture issue of aging could in turn ease the burden of many diseases, not just Alzheimer's disease. Quite intriguingly, their research reaffirms a long-standing scientific position that the aging process is reversible and that the endocrine system can be repurposed to mediate these changes later in life [5, 6]. It is important to note, that this study explores the unwanted consequences of Alzheimer's, such as the degenerate loss of neural function, and does not necessarily correct the root cause.
Improving Stem Cells in the Current Era
So while our understanding of the aging process and the many factors that contribute to producing stem cells has improved, many limiting ethical and biological factors remain. This is particularly true for embryonic stem cells (ESCs) and for the less productive adult stem cell (ASC) lines, which are not immediately pluripotent. Still, only limited progress has been made through available ESC lines despite their ability to become any cell in the human body.
ESCs hold great promise for developing cell therapy techniques. Their use, however, posed two serious problems to researchers. Biologically, they can easily adapt in many cellular environments, and their high rate of proliferation leads to an increased risk for cancerous tumors. There are also the ethical considerations since the only source is from embryos (albeit at the early blastocyst stage weeks before fetal development begins).
As an alternative, ASCs were seen as the most likely candidate to replace ESCs, but they must first be artificially reprogrammed and maintained in culture in order to be used for rehabilitative therapy. Because ASCs are not immediately pluripotent, success with these cell lines will depend to a large extent on our ability to identify and then manipulate the genetic factors that underlie their growth and proliferation a goal that modern methods promise to achieve.
The current reprogramming protocols call for twice the amount of OCT4 and KLF4 when compared with SOX2 and cMYC. The results produce iPS cells that are genetically and epigenetically stable and are fully pluripotent. More importantly, when this reprogramming method were tested in mice, these iPS cells did not produce tumors when compared to the original protocol and appeared to be immune tolerant [7].