Does Platelet-Rich Plasma Increase Tendon Metabolism?

Platelet-rich plasma in the pathologic processes of tendinopathy: a review of basic science studies

Tendinopathy is a medical condition that includes a spectrum of inflammatory and degenerative tendon changes caused by traumatic or overuse injuries. The pathological mechanism of tendinopathy has not been well defined, and no ideal treatment is currently available. Platelet-rich plasma (PRP) is an autologous whole blood derivative containing a variety of cytokines and other protein components. Various basic studies have found that PRP has the therapeutic potential to promote cell proliferation and differentiation, regulate angiogenesis, increase extracellular matrix synthesis, and modulate inflammation in degenerative tendons. Therefore, PRP has been widely used as a promising therapeutic agent for tendinopathy. However, controversies exist over the optimal treatment regimen and efficacy of PRP for tendinopathy. This review focuses on the specific molecular and cellular mechanisms by which PRP manipulates tendon healing to better understand how PRP affects tendinopathy and explore the reason for the differences in clinical trial outcomes. This article has also pointed out the future direction of basic research and clinical application of PRP in the treatment of tendinopathy, which will play a guiding role in the design of PRP treatment protocols for tendinopathy.

Platelet-Rich Plasma Diffusion in Achilles Tendon: Relationship with Therapeutic Outcomes

OBJECTIVE

The therapeutic efficacy of platelet-rich plasma in the treatment of Achilles tendinopathy is controversial. Among the variables which can explain the discrepant results, little attention has been paid to the distribution of platelet-rich plasma inside the tendon. The aim of the present study was to evaluate whether this factor is related to the clinical outcome of treatment.

SUBJECTS AND METHODS

Forty patients suffering from mid-portion Achilles tendinopathy were studied. At baseline, pain and function were measured by means of a visual analogue scale and the Victorian Institute of Sport Assessment-Achilles questionnaire. Thereafter, an ultrasound examination was performed, and platelet-rich plasma was injected. Immediately after injection, the plasma distribution was assessed visualizing the material in the tendon. The patients were re-evaluated at 3 and 6 months, computing pain and function values and the percentage of satisfactory outcomes in relation to the distance reached by the plasma from the point of injection.

RESULTS

The diffusion inside the tendon was longitudinal in all cases and cross-sectional only in 9. The mean distance from the tip of the needle increased significantly according to the severity of tendon damage. At follow-up, no relationship was found between plasma diffusion and clinical outcomes.

CONCLUSIONS

Platelet-rich plasma diffusion has no effect on clinical outcome, which mainly depends on the metabolic activation of the whole structure of the tendon.

Effects of Platelet-Rich Plasma on Tissue Expansion in Rabbits

BACKGROUND

Tissue expansion has been widely applied in clinic practice. However, the expanded skin is always insufficient for clinical use and how to promote tissue expansion is still a challenge. Platelet-rich plasma (PRP) contains multiple tissue growth factors and has been widely utilized in hard- and soft-tissue augmentation. However, its feasibility to promote tissue expansion has not been explored. The purpose of this study was to evaluate the possible effect of PRP in tissue expansion.

METHODS

Tissue expanders were implanted in the dorsal sides of rabbit ears, and the left and right side were for the PRP group and the control group randomly. The PRP group was injected with 1.0 mL of autologous PRP in the expansion skin and the control group with the same volume of saline solution. The expanders were inflated regularly by injecting saline solution under the same pressure. After the inflation phase, the expansion skin was harvested and the inflation volume, gross specimen, and histological characteristics were assayed and evaluated.

RESULTS

The mean inflation volume of the PRP group was significantly higher than that of the control (p < 0.05). H&E staining of expanded skin sections showed more epidermal cell layers and thicker skin in the PRP group than that in the control group. There were significantly more capillaries in the expanded skin in the PRP group than those from the control group by IHC staining with its marker anti-CD31. A higher level of mRNA expression of VEGF was observed in the PRP group by real-time PCR.

CONCLUSIONS

The present study suggests that PRP plays a pivotal role in tissue expansion and skin proliferation.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors. www.springer.com/00266 .