The effect of platelet‐rich plasma on the neovascularization of surgically created equine superficial digital flexor tendon lesions

Abstract

The repair process of tendon injuries, which are common in both human and equine athletes, is slow and the quality of the repair tissue is often inferior to the original tendon tissue, which frequently leads to re-injury. The relatively poor vascularization of tendons is considered to be one of the reasons for their limited healing potential. Recently, platelet-rich plasma (PRP), an autologous concentrate of platelets, rich in growth factors, has been shown to enhance the repair process of injured tendons. This effect has been ascribed to the high levels of growth factors in PRP, several of which are known to be involved in tendon repair. Among many other growth factors, the vascular endothelial growth factor, a powerful stimulator of angiogenesis, is abundantly present in PRP, suggesting that enhancement of neovascularization might be one of the working mechanisms. In this study, the effect of PRP on neovascularization was studied in experimentally induced tendon injuries using color Doppler ultrasonography and immunological staining of Factor VIII. PRP induced significantly more neovascularization than the placebo treatment until at least 23 weeks after treatment, as detected by both Doppler ultrasonography and Factor VIII staining. Neovascularization might be one of the explanations for the long-lasting effect of a single intratendinous treatment with PRP.

Influence of Platelets Rich Plasma on Repair of Superficial Digital Flexor Tendon Rupture in Donkeys (An Experimental Study)

“…These results could be attributed to the powerful and long-term analgesic and anti-inflammatory effect of intra tendentious PRP via its growth factors. Also, different authors attributed these findings to paramount regenerative role of intratendinous PRP which enhance early granulation formation, cellular proliferation and differentiation and gradual arrangement of tendon fibers bundle [6,29]. These findings were supported histopathologically in the present study and in another reported one [30].…”

“…The exact mechanisms of PRP on the inflammatory response after acute tendon injury is not excluded yet, but many studies postulated that the therapeutic effects of PRP in tendon repair could be attributed to the high content of PRP in many growth factors and anti-inflammatory cytokines such as PDGF, IGF-I, bFGF, VEGF and HGF, EGF, DAF, platelet factor 4, ECGF, FGF and stromal cell derived factor 1α [6,[11][12][13]. These factors had major effects on tendon repair via promoting angiogenesis, fibroblast proliferation, leukocyte chemotaxis, collagen deposition, and remodeling [29][30][31].…”

Platelet rich plasma treatment of superficial digital flexor tendon lesions in racing Thoroughbreds

“…In the follow-up period all patients ran a combined total of 64 races and horses with severe injury started in 58% races, moderately-injured horses ran in 30% races and mildly injured animals ran in 12%, respectively. Bosch et al (2011) recommended only one intralesional application of PRP in the acute stage of the injury but Textor (2011) who also reported management of SDFT injuries in the acute stage recommended repeated application. In our study we applied PRP in all cases only once because the lesion was ultrasonographically not visible during the control examination.…”

“…al., 2012). Bosch et al (2010Bosch et al ( , 2011 studied the healing of a mechanically-induced experimental central core lesion in the SDFT of a horse and found, after only one application of PRP into the lesion, a significant positive effect on the biochemical, biomechanical and histological characteristics of the healing process. The healed tissue was rich in collagen fibres and glycosaminoglycans compared to the control group.…”

The past, present and future in scaffold-based tendon treatments

“…To this end, platelet rich plasma (PRP), a natural concentrate of many growth factors [182][183][184], is under intense investigation. PRP has been proposed as a therapy for the treatment of equine tendon injuries, with data demonstrating development and maturation of a healing tendon tissue, based on improved metabolic activity, increased failure strength and elastic modulus of the repairing tissues and increased neovascularisation, over the saline injected counterparts in an equine superficial digital flexor tendon model [185][186][187][188]. In a clinical setting, PRP injections have been used under various identifying names for decades [189,190]; however long-term, large and blinded studies have yet to be reported, with current data contradicting each other.…”