Researchers Used iPSC to Reverse Parkinson’s Disease Symptoms

As the population continues to age, a pandemic of Parkinson’s disease (PD) is emerging, with conservative estimates of over 14 million victims globally by 2040. While PD patients display a wide range of non-motor features, the defining symptoms are progressive motor deficits due to striatal dopaminergic insufficiency secondary to loss of dopaminergic nigral neurons. 

Current treatments are symptomatic, mostly focused on ameliorating motor deficits, but no therapy arrests or reverses the disease process. 

Recently, a group of researchers has reversed motor symptoms of PD in rats by implanting induced pluripotent stem cells (iPSC) to replace neurons destroyed by the disease. iPSC are cells that have been reprogrammed back into an embryonic-like state. The results appear in the journal npj Regenerative Medicine. 

Promising Results for PD Patients

Studies have shown that iPSCs can be differentiated into midbrain dopaminergic (mDA) neurons and reverse motor deficits in animal models. Researchers examined the engraftment, innervation, and functional efficacy in a rat model using cells from different developmental stages for the current study. 

The team teated the cells in their embryonic-like state with a set of additional factors and cultured the cells for 17, 24, and 37 days, and found that at 17 days progenitors were markedly superior in terms of survival and effects on motor deficits. 

The cells demonstrated intranigral engraftment to the ventral midbrain. The team also evaluated the appropriate dosing of iPSC and found that at around 450,000 by 4 months there was a complete and functional recovery in the rats. 

The team did not observe teratoma formation or significant outgrowth of other cells in any animal. 

The same team expects to start clinical trials in humans that have PD with specific mutations in the Parkin gene, and if successful, more extensive trials may follow in a broader population of people with PD. 


Hiller, B.M., Marmion, D.J., Thompson, C.A. et al. Optimizing maturity and dose of iPSC-derived dopamine progenitor cell therapy for Parkinson’s disease. npj Regen Med 7, 24 (2022).

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