Tendinopathy also involves an increase in inflammatory mediators such as prostaglandin E2 and interleukin -1, an enhanced expression of cyclooxygenase 2, growth factors including TGF-β and platelet derived growth factor (PDGF), insulin-like growth factor-1 (IGF-1) and neurotransmitters such as glutamate and substance P [66,67,68,69,70,71,72]. Here, IGF1 is linked to disease of the tendon.