TABLE 5.

Promising attempts, limitations and discussing points in NSC/NPC treatment for chronic SCI.

Promising attempts	References	Limitations/ Discussion points	References
Improvement of functional outcome	Moviglia et al., 2009; Kusano et al., 2010; Karimi-Abdolrezaee et al., 2010; Salazar et al., 2010; Cheng et al., 2016; Tashiro et al., 2016; Suzuki et al., 2017; Nori et al., 2018; Okubo et al., 2018; Jones et al., 2021	Partial functional recovery	Tetzlaff et al., 2011; Oh et al., 2016; Anderson et al., 2017; Lane et al., 2017; Deng et al., 2018; Tsuji et al., 2019; Yamazaki et al., 2020; Nagoshi et al., 2020; Suzuki and Sakai, 2021
Grafted NSC/NPC survive in chronic SCI lesion		Partial control of directing cell differentiation
Differentiate into neuronal lineages -Neuron, Oligodendrocyte and Astrocyte-		Limitation of functional integration with the host neural circuitry
Promotion of axon regrowth		Variability in both anatomical and functional outcomes
Reduction of cyst volume		Safety in clinical trials (NSC/NPC source)
Promotion of Neural Pathway Plasticity	Pfeifer et al., 2006; Ruzicka et al., 2019; Xu et al., 2021	Lack of control on the processes rewiring the neural new circuits.
Remyelination		Administration route -Intramedullary, Intrathecal, Intraventricular and Intravascular-
		Optimal time-window of efficacy
		Issue of cost-benefit ratio