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 retinal or optic nerve disorders. 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 ONA include (11):

• 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 ONA and retinal disorders – have better differentiation capacity into retinal cells, and have better anti-cell death effect in case of degenerative conditions like ONA that already have an ongoing destructive process – compared to other stem cells.
• 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.

After carefully reviewing all of the benefits and risks of each type, we have decided to use mesenchymal umbilical cord-based stem cells that have been most extensively studied; with the least reported side effects.

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 ONA and retinal disorders use combined routes of administration including (11):

• Intravenous (Into the blood)
• Intrathecal (Into the CSF surrounding the brain)
• Retrobulbar (Behind the eye where the optic nerve resides)
• Intraocular (Into the eye)
• Intravitreal routes (Into the vitreous of the eye)

At Beike, we use combined intravenous and intrathecal routes; with some patients being eligible for two additional retrobulbar injections depending on different factors.