To date, there has not been a single study – to our knowledge – that has compared different types of stem cells, concerning safety and efficacy, particularly in patients with NTDs. However, we can summarize different stem cell sources that have been tested in these disorders. Each form of stem cells has its own benefits and drawbacks as will be mentioned. Different stem cell sources that have been tested in different neurological disorders include (3, 6, 10):
– Mesenchymal Stem Cells: These are stem cells obtained from adipose tissues, bone marrow, or umbilical cord tissues – which we actually use at Beike. These cells can be easily produced in larger numbers to accommodate higher number of patients and allow better efficacy, have better response in neurological diseases – including spina bifida – have better differentiation capacity into neurons, and have better anti-cell death effect in case of degenerative conditions like NTDs that affect neurological development– compared to other stem cells. Mesenchymal stem cells can be obtained from different sources including the umbilical cord, bone marrow, and adipose tissue.
– Embryonic Stem Cells: Another type of stem cells includes embryonic stem cells. These cells can also differentiate into photoreceptors; yet they are difficult to obtain and have ethical concerns regarding their sources.
– Adult Pluripotent Stem Cells: These are another source that can be produced in large numbers; yet their differentiation abilities are once again limited.
– Neural Stem Cells: These are another type that has particular benefits in neurological diseases through the production of neurotrophic factors; though their differentiation is also limited
After carefully reviewing all of the benefits and risks of each type, we have decided to use mesenchymal umbilical cord-based stem cells as our main source since they have been the most extensively studied type in neurological conditions, including NTDs, with the least reported side effects (5, 6, 8). This is in addition to also using umbilical cord blood cells (hematopoietic cells) concurrently to provide additional benefits from using two types of stem cells; with each contributing to neuro-regeneration through different complementary mechanisms.
In addition to the source of stem cells, there are also multiple routes of stem cell administration. Most clinical trials testing stem cell therapy in spina bifida use either one of two routes; which are (8, 9):
– Intravenous (Into the blood)
– Intrathecal (Into the CSF surrounding the brain through lumbar puncture)
At Beike, we use combined intravenous and intrathecal routes concomitantly to achieve the best results with the least possible side effects.