Cell therapy represents a fundamentally different approach to treating neurodegenerative diseases by transplanting living cells into the brain to replace lost neurons, provide trophic support, or modulate the immune system. While still largely experimental, this modality offers the unique potential to regenerate damaged neural circuits—a goal no other therapeutic approach can achieve. The field has evolved from early experiments with fetal tissue transplantation to sophisticated approaches using induced pluripotent stem cells (iPSCs) and engineered cell populations.
Cell therapies work through several mechanisms:
- Transplanting neurons or neuronal progenitors to replace lost cells
- Establishing synaptic connections with host neurons
- Restoring neural circuit function
- Providing healthy microglia to replace dysfunctional cells
- Supporting neuronal survival and function
- Modulating the brain immune environment
- Cells engineered to secrete neurotrophic factors
- Supporting survival of endogenous neurons
- Promoting plasticity and repair
- Regulatory immune cells to dampen neuroinflammation
- Modulating the brain's immune response
- Reducing toxic inflammation
| Program |
Company |
Cell Type |
Indication |
Phase |
| iPSC dopaminergic neurons |
Kyoto University/iPS Japan |
iPSC-derived DA neurons |
Parkinson's disease |
Phase 1/2 |
| iN-Dopa |
BlueRock Therapeutics |
iPSC-derived DA neurons |
Parkinson's disease |
Phase 1 |
| NSI-566 |
Neuralstem |
Neural progenitor cells |
ALS |
Phase 2 |
| Astron-001 |
Astron |
Autologous MSCs |
ALS |
Phase 1/2 |
| HESC-derived DA neurons |
Novo Nordisk |
hESC-derived DA neurons |
Parkinson's disease |
Preclinical |
Parkinson's Disease
- iPSC-derived dopaminergic neurons: Clinical trials underway in Japan using patient-derived iPSCs
- Allogeneic hESC-derived neurons: BlueRock Therapeutics and others in early trials
- Mesenchymal stem cells: Immunomodulatory and trophic effects
Amyotrophic Lateral Sclerosis
- Neural progenitor cells: Phase 2 trial showed possible slowed progression
- MSC-NTF cells: Phase 1/2 showing safety and potential efficacy
- iPSC-derived motor neurons: Preclinical
Alzheimer's Disease
- Cholinergic neurons: Early development
- Glial progenitor cells: Myelin repair and neuroprotection
- Microglial replacement: Aspen Neuroscience program
An alternative approach involves encapsulating cells that secrete therapeutic proteins:
- NTC-200: Encapsulated cells secreting GDNF-like factors
- Cellular "factories": Engineered to produce therapeutic proteins
- Advantages: Avoids immunosuppression, retrievable
- Potential to replace lost neurons
- Restore neural circuit function
- Address root cause of neuronal loss
- Continuous delivery of protective factors
- Support endogenous repair mechanisms
- Promote synaptic plasticity
- Patient-derived iPSCs enable disease modeling
- Drug screening in patient-derived cells
- Personalized medicine potential
- Address neuroinflammation component
- Modulate microglial function
- Reduce toxic immune responses
- iPSC-derived cells from patient
- Avoid immune rejection
- Personalized therapy potential
- Undifferentiated stem cells may form teratomas
- Malignant transformation possible
- Rigorous purification required
- Allogeneic cells face immune attack
- Immunosuppression required
- Autologous iPSCs avoid this issue but are expensive
- Invasive neurosurgical procedures
- Precise placement critical
- Limited distribution within brain
¶ Survival and Integration
- Host environment may be hostile
- Limited survival in disease brain
- Functional integration challenging
- Autologous iPSC approaches costly and time-consuming
- Scalability challenges
- Quality control for each batch
- Early-stage trials
- Clinical benefit not yet demonstrated
- Long-term outcomes unknown
- Pluripotent, can become any cell type
- Well-characterized
- Ethical considerations
- Allogeneic use potential
- Patient-derived, avoid immune issues
- Reprogrammed from adult cells
- Personalized medicine potential
- Cost and time-intensive
- Immunomodulatory properties
- Easy to obtain (bone marrow, adipose)
- Trophic factor secretion
- Limited differentiation potential
- Already committed to neural lineage
- Safer than pluripotent cells
- Limited expansion capacity
- Chimeric antigen receptor (CAR) cells
- Gene-edited cells
- Synthetic biology approaches
- Correcting genetic mutations in patient-derived cells
- Engineering enhanced therapeutic properties
- Creating "universal" donor cells
¶ 3D Culture and Organoids
- Brain organoids for drug screening
- Patient-specific disease modeling
- Therapeutic testing platforms
- Cell therapy + small molecule
- Cell therapy + gene therapy
- Multiple cell types
- Stereotactic injection improvements
- Intravascular delivery with brain shuttles
- Minimally invasive approaches