NTF4 and neuropathy: Andreassen et al. found that a down regulation of neurotropic factors activity such as neurotrophin 3 (NT-3) and neurotrophin 4 (NT-4) released from end of motor and sympathetic axons to periphery in the T2DM and the amount of downregulation was significantly more in patients with than without neuropathy and correlated to gastrocnemius strength [32].