Stem Cell Therapy for Neurodegenerative Diseases: How Do Stem Cells Bypass the Blood-Brain Barrier and Home to the Brain?

Table 1

Benefit and limitation of stem cells as a therapeutical tool in neurodegenerative diseases.

Benefit	Limitation
(i) Possess neuroprotective and immunomodulatory properties which promote tissue repair and regeneration	(i) Underlying mechanism of action remains unclear and will require more detailed investigations
(ii) Capable of migrating across the endothelial cell of BBB	(ii) Must successfully overcome the BBB in order to exert therapeutic effects in the brain
(iii) Capable of homing back to the side of injury to initiates endogenous repair	(iii) Homing potential is influenced by the delivery method
(iv) Absence of cell replacement evidence; trophic effects likely induce transient recovery	(iv) Sufficient numbers of cells reaching the target site are necessary to exert a therapeutical effect
(v) Generally well-accepted with no serious adverse effects such as infection or tumour	(v) Treatment outcome may be affected by various factors including the donor’s age, host tissue, and growth regulators expressed by recipient tissue