Applications cliniques du plasma riche en plaquettes (PRP) dans les lésions tendineuses : revue de la littérature

[Platelet-rich plasma (PRP) and disc lesions: A review of the literature]

The spine has been the subject of extensive clinical research since it is the source of many painful complaints. However, there is little scientific evidence concerning the therapeutic proposals. During the course of life, the intervertebral disc degenerates, which over time diminishes its damping capacity and facilitates the expulsion of the nucleus pulposus through the annulus fibrosus. The degeneration of the intervertebral disc (DDI) is the origin of some back pain and various specific treatments have been developed. These include the infiltration at the center of the intervertebral disc of plasma rich platelet (PRP), composed of multiple growth factors which act on the disc degeneration. This treatment is recent and less invasive than surgery. Preliminary results seem promising. However, many gray areas and several parameters remained to be clarified. In an attempt to do this, a literature review was conducted based on bibliographic databases Pubmed, Medline and Scopus^® using the following Mesh terms : PRP, platelet-rich plasma, intradiscal disc degeneration, disc, intradiscal, discogenic. This analysis reveals that at the present time, no reported study has a sufficient perspective to judge the effectiveness of the infiltration of PRP. Early harvest results will be used to set the limits of this treatment. Accordingly, it is therefore currently recommended to introduce PRP injection as a complementary solution to comprehensive care of the spine. Future research will need to generate randomized controlled studies including comparing the results with conservative treatment and measure the cost-benefit relationship.

Responders to Platelet-Rich Plasma in Osteoarthritis: A Technical Analysis

Purpose

To evaluate the similarities and differences between the variety of platelet-rich plasma (PRP) formulations, preparation, and uses to try to determine the best responses for the treatment of knee osteoarthritis.

Materials and Methods

A comparison of the outcomes of randomized controlled trials (RCTs) included in the 3 most recent and high-quality meta-analyses to classify the different studies in 2 groups (bad responders group (BRG) and very good responders group (VGRG)).

Results and Discussion

From the 19 RCTs analyzed, 7 trials were included in the VGRG and 4 in the BRG. In VGRG, 1 or 2 injections were performed in 4/7 trials, time between injections was 2 to 3 weeks in 4/5 studies with many injections, volume injected varied from 2.5 to 8 mL, and single spinning technique was used in 5/7 studies. PRP classification was Mishra 4B and PAWP2Bβ in 5/7 studies. The use of PRP with leukocytes is only found in the BRG.

Conclusion

There is a lack of standardization in PRP preparation technique for knee osteoarthritis. However it appears that the use of a single spinning technique, a platelet concentration lower than 5 times the baseline, and avoidance of leukocytes should be preferred.

The use of platelet-rich plasma to treat chronic tendinopathies: A technical analysis

Platelet-rich plasma (PRP) is blood plasma with a high concentration of autologous platelets which constitute an immense reservoir of growth factors. The clinical use of PRP is widespread in various medical applications. Although highly popular with athletes, the use of PRP for the treatment of tendinopathies remains scientifically controversial, particularly due to the diversity of products that go by the name of "PRP." To optimize its use, it is important to look at the various stages of obtaining PRP. In this literature review, we take a closer look at eight parameters which may influence the quality of PRP: 1) anticoagulants used to preserve the best platelet function, 2) the speed of centrifugation used to extract the platelets, 3) the platelet concentrations obtained, 4) the impact of the concentration of red and while blood cells on PRP actions, 5) platelet activators encouraging platelet degranulation and, hence, the release of growth factors, and 6) the use or nonuse of local anesthetics when carrying out infiltration. In addition to these parameters, it may be interesting to analyze other variables such as 7) the use of ultrasound guidance during the injection with a view to determining the influence they have on potential recovery.

Does platelet-rich plasma have a role in the treatment of osteoarthritis?

Platelet-rich plasma (PRP) has been generating considerable attention as an intra-articular treatment to alleviate the symptoms of osteoarthritis. Activated platelets release a host of soluble mediators such as growth factors and cytokines, thereby inducing complex interactions that vary across tissues within the joint. In vivo, PRP may promote chondrocyte proliferation and differentiation. The available data are somewhat conflicting regarding potential effects on synovial cells and angiogenesis modulation. PRP probably exerts an early anti-inflammatory effect, which may be chiefly mediated by inhibition of the NF-κB pathway, a hypothesis that requires confirmation by proof-of-concept studies. It is far too early to draw conclusions about the efficacy of PRP as a treatment for hip osteoarthritis. The only randomized trial versus hyaluronic acid showed no significant difference in effects, and no placebo-controlled trials are available. Most of the randomized trials in knee osteoarthritis support a slightly greater effect in alleviating the symptoms compared to visco-supplementation, most notably at the early stages of the disease, although only medium-term data are available. Many uncertainties remain, however, regarding the best administration regimen. Serious adverse effects, including infections and allergies, seem rare, although post-injection pain is more common than with other intra-articular treatments for osteoarthritis.

Platelet-rich plasma in orthopedic therapy: a comparative systematic review of clinical and experimental data in equine and human musculoskeletal lesions

BACKGROUND

This systematic review aimed to present and critically appraise the available information on the efficacy of platelet rich plasma (PRP) in equine and human orthopedic therapeutics and to verify the influence of study design and methodology on the assumption of PRP's efficacy. We searched Medline, PubMed, Embase, Bireme and Google Scholar without restrictions until July 2013. Randomized trials, human cohort clinical studies or case series with a control group on the use of PRP in tendons, ligaments or articular lesions were included. Equine clinical studies on the same topics were included independently of their design. Experimental studies relevant to the clarification of PRP's effects and mechanisms of action in tissues of interest, conducted in any animal species, were selected.

RESULTS

This review included 123 studies. PRP's beneficial effects were observed in 46.7% of the clinical studies, while the absence of positive effects was observed in 43.3%. Among experimental studies, 73% yielded positive results, and 7.9% yielded negative results. The most frequent flaws in the clinical trials' designs were the lack of a true placebo group, poor product characterization, insufficient blinding, small sampling, short follow-up periods, and adoption of poor outcome measures. The methods employed for PRP preparation and administration and the selected outcome measures varied greatly. Poor study design was a common feature of equine clinical trials. From studies in which PRP had beneficial effects, 67.8% had an overall high risk of bias. From the studies in which PRP failed to exhibit beneficial effects, 67.8% had an overall low risk of bias.

CONCLUSIONS

Most experimental studies revealed positive effects of PRP. Although the majority of equine clinical studies yielded positive results, the human clinical trials' results failed to corroborate these findings. In both species, beneficial results were more frequently observed in studies with a high risk of bias. The use of PRP in musculoskeletal lesions, although safe and promising, has still not shown strong evidence in clinical scenarios.

Platelet-rich plasma and skeletal muscle healing: a molecular analysis of the early phases of the regeneration process in an experimental animal model

Platelet-rich plasma (PRP) has received increasing interest in applied medicine, being widely used in clinical practice with the aim of stimulating tissue healing. Despite the reported clinical success, there is still a lack of knowledge when considering the biological mechanisms at the base of the activity of PRP during the process of muscle healing. The aim of the present study was to verify whether the local delivery of PRP modulates specific molecular events involved in the early stages of the muscle regeneration process. The right flexor sublimis muscle of anesthetized Wistar rats was mechanically injured and either treated with PRP or received no treatment. At day 2 and 5 after surgery, the animals were sacrificed and the muscle samples evaluated at molecular levels. PRP treatment increased significantly the mRNA level of the pro-inflammatory cytokines IL-1β, and TGF-β1. This phenomenon induced an increased expression at mRNA and/or protein levels of several myogenic regulatory factors such as MyoD1, Myf5 and Pax7, as well as the muscular isoform of insulin-like growth factor1 (IGF-1Eb). No effect was detected with respect to VEGF-A expression. In addition, PRP application modulated the expression of miR-133a together with its known target serum response factor (SRF); increased the phosphorylation of αB-cristallin, with a significant improvement in several apoptotic parameters (NF-κB-p65 and caspase 3), indexes of augmented cell survival. The results of the present study indicates that the effect of PRP in skeletal muscle injury repair is due both to the modulation of the molecular mediators of the inflammatory and myogenic pathways, and to the control of secondary pathways such as those regulated by myomiRNAs and heat shock proteins, which contribute to proper and effective tissue regeneration.

Exuberant inflammatory reaction as a side effect of platelet-rich plasma injection in treating one case of tendinopathy

Platelet-rich plasma (PRP) contains a large number of growth factors, which may enhance tendon healing processes. Local injection of PRP represents a relatively new treatment for tendinopathies. To date, no side effects have been reported after injection of PRP to treat tendinopathy. We report a case of exuberant inflammatory reaction after 1 injection of PRP to treat jumper's knee in a 35-year-old male type 1 diabetic patient. Injections of PRP should be proposed only after careful consideration in cases of patients with morbidity risks linked to insulin-dependent diabetes.