TABLE 1.

Neurotrophic and neurotropic molecules that are expressed by the Schwann cells in the distal endoneural tubes.

Neurotrophic factors
Axonal growth promoters	NGF, BDNF, NT3, NT4/5	Boyd and Gordon, 2003; Jin et al., 2009; Li et al., 2020
Transforming growth factors	GDNF	Allodi et al., 2012; Hoyng et al., 2014; Anand et al., 2017
Insulin-like growth factors	IGF1 e IGF2	Di Giulio et al., 2000; Brushart et al., 2013
Fibroblast growth factors	FGF2	Allodi et al., 2012; Brushart et al., 2013; Santos et al., 2016b
Neuropoietic cytokines	PTN, CNTF, IL6, LIF	Mi et al., 2007; Gordon, 2014
Molecules integrated into the surrounding nerve tissue
Axonal growth promoters	N-CAM, N-cadherin, L1, integrins, etc.	Seilheimer and Schachner, 1988; Smith et al., 1994; Hammarberg et al., 2000; Franz et al., 2005; Saito et al., 2005, 2010; Gardiner et al., 2007; Tucker and Mearow, 2008; Gardiner, 2011; Anand et al., 2017
Extracellular matrix molecules	fibrinogen, fibronectin, laminin, etc.	Politis, 1989; Hammarberg et al., 2000; Zhang et al., 2003; Previtali et al., 2008; Tucker and Mearow, 2008; Webber et al., 2008; Gardiner, 2011; Fudge and Mearow, 2013; Zeng et al., 2014; Santos et al., 2016b

Each endoneural tube contains a specific blend of such molecules depending on the type of its axon (i.e., sensory or motor). Moreover, blends change in time.