Regenerative medicine in Huntington's disease: Strengths and weaknesses of preclinical studies

- Rodent models are crucial to assess the therapeutic efficacy of stem cell transplantation in HD.
- Behavioural, morphological and molecular effects of cell therapy should be assessed longitudinally.
- Experimental studies support moderate functional efficacy of SCs therapy in HD rodent models.
- Training and environment can influence graft-derived functional recovery in HD rodent models.
- Screening of different HD models would speed translation of cell therapy from bench to clinic.

Huntington's disease (HD) is an inherited neurodegenerative disorder, characterized by impairment in motor, cognitive and psychiatric domains. Currently, there is no specific therapy to act on the onset or progression of HD. The marked neuronal death observed in HD is a main argument in favour of stem cells (SCs) transplantation as a promising therapeutic perspective to replace the population of lost neurons and restore the functionality of the damaged circuitry. The availability of rodent models of HD encourages the investigation of the restorative potential of SCs transplantation longitudinally. However, the results of preclinical studies on SCs therapy in HD are so far largely inconsistent; this hampers the individuation of the more appropriate model and precludes the comparative analysis of transplant efficacy on behavioural end points. Thus, this review will describe the state of the art of in vivo research on SCs therapy in HD, analysing in a translational perspective the strengths and weaknesses of animal studies investigating the therapeutic potential of cell transplantation on HD progression.