Tenology: a new frontier

Platelet-Rich Plasma (PRP) Injection in Sports Injuries

BACKGROUND

Sports injuries are very common, and the management demands high degrees of skills and best techniques for an early return to play. The use of Platelet Rich Plasma (PRP) injections in the treatment of tendon, muscle and ligament injuries has become popular. This study observes the outcomes of PRP injections in sports injuries.

METHODS

Forty-eight athletes (mean age 29.93 ± 8.48, Male: 37, Female: 11) presenting to a sports medicine centre with different sports injuries with symptom duration (2.81 ± 1.94) months were given PRP injections (single or multiple) four weeks apart with maximum number of injections up to three depending upon the clinical condition, Pre and Post VAS scores. Specific rehabilitation program was administered and compliance was graded by Sports Injury Rehabilitation Adherence Scale (SIRAS). A 1 year follow-up of cases was done for assessing player satisfaction and return to play.

RESULTS

Pre-procedure (7.25 ± 0.70) and post-procedure (2.42 ± 0.74) VAS score for all athletes showed significant difference with a p value at 0.0001. The average number of injections was 1.35 ± 1.41 with 72.91% requiring only one injection while 18.75% and 8.33% required two and three injections, respectively.

CONCLUSION

Athletes who required a single injection for acute injuries of lower grade returned to sports activity earlier than those who required multiple injections for chronic injuries. PRP injection has optimal effects on sports injuries not responding to conservative management.

Antiapoptotic effects of anthocyanins on rotator cuff tenofibroblasts

Degeneration of the rotator cuff tendon, which involves apoptosis of the tenofibroblasts, is one of the most common shoulder problems that can lead eventually to a full-thickness rotator cuff tendon tear. The current authors evaluated both the ability of anthocyanins, which are powerful antioxidants, to reduce apoptosis in oxidation-stressed rotator cuff tenofibroblasts, and the molecular mechanism for this antiapoptotic action. Anthocyanins demonstrated a dose-dependent ability to inhibit H(2)O(2)-induced apoptosis in cultured tenofibroblasts, as assessed by MTT assay and FACS analysis. H(2)O(2) increased the phosphorylation of extracellular regulated kinase1/2 (ERK1/2) and of c-Jun N-terminal kinase (JNK) and the production of reactive oxygen species (ROS). In contrast, treatment with anthocyanins decreased this activation of ERK1/2 and JNK, as confirmed by Western blot analysis, and reduced the production of ROS, as verified by fluorescent microscopic and FACS analyses. These findings suggest that anthocyanins, by suppressing JNK, ERK1/2, and intracellular ROS production, have a concentration-dependent antiapoptotic effect on rotator cuff tenofibroblasts exposed to an oxidative stressor, and may have therapeutic potential.

Platelet rich plasma injection grafts for musculoskeletal injuries: a review

In Europe and the United States, there is an increasing prevalence of the use of autologous blood products to facilitate healing in a variety of applications. Recently, we have learned more about specific growth factors, which play a crucial role in the healing process. With that knowledge there is abundant enthusiasm in the application of concentrated platelets, which release a supra-maximal quantity of these growth factors to stimulate recovery in non-healing injuries. For 20 years, the application of autologous PRP has been safely used and documented in many fields including; orthopedics, sports medicine, dentistry, ENT, neurosurgery, ophthalmology, urology, wound healing, cosmetic, cardiothoracic, and maxillofacial surgery. This article introduces the reader to PRP therapy and reviews the current literature on this emerging treatment modality. In summary, PRP provides a promising alternative to surgery by promoting safe and natural healing. However, there are few controlled trials, and mostly anecdotal or case reports. Additionally the sample sizes are frequently small, limiting the generalization of the findings. Recently, there is emerging literature on the beneficial effects of PRP for chronic non-healing tendon injuries including lateral epicondylitis and plantar fasciitis and cartilage degeneration (Mishra and Pavelko, The American Journal of Sports Medicine 10(10):1–5, 2006; Barrett and Erredge, Podiatry Today 17:37–42, 2004). However, as clinical use increases, more controlled studies are needed to further understand this treatment.

Autologous preparations rich in growth factors promote proliferation and induce VEGF and HGF production by human tendon cells in culture

Blood platelets become activated and aggregate at the site of vessel injury. Upon activation by thrombin, platelets release storage pools of proteins and growth factors (GFs), including those involved in tissue repair. Our goal was to evaluate the potential beneficial effect of proteins released from platelet-rich clots on tendon healing. PDGF, TGF-beta-1, IGF-I, HGF, VEGF and EGF were measured in human platelet-poor plasma (PPP) and in the releasates collected from either platelet-poor or platelet-rich clots prepared in vitro. We then studied the effects of the releasates on human tendon cells in culture. Releasates from both platelet-rich and platelet-poor clots stimulated tendon cell proliferation, in contrast to un-clotted PPP. The mitogenic activity of the supernatants was not decreased by the thrombin inhibitor, hirudin. Cultured tendon cells synthesise VEGF and HGF in the presence of PPP-clots and PRP-clot releasates, thus the synthesised amount was significantly higher with supernatants from platelet-rich clots than supernatants from a platelet-poor clot (p < 0.05). These results suggest that administering autologous platelet-rich clots may be beneficial to the treatment of tendon injuries by inducing cell proliferation and promoting the synthesis of angiogenic factors during the healing process.

Proliferation and collagen production of human patellar tendon fibroblasts in response to cyclic uniaxial stretching in serum-free conditions

We studied the effect of cyclic mechanical stretching on the proliferation and collagen mRNA expression and protein production of human patellar tendon fibroblasts under serum-free conditions. The role of transforming growth factor-beta1 (TGF-beta1) in collagen production by cyclically stretched tendon fibroblasts was also investigated. The tendon fibroblasts were grown in microgrooved silicone dishes, where the cells were highly elongated and aligned with the microgrooves. Cyclic uniaxial stretching with constant frequency and duration (0.5 Hz, 4 h) but varying magnitude of stretch (no stretch, 4%, and 8%) was applied to the silicone dishes. Following the period of stretching, the cells were rested for 20 h in stretching-conditioned medium to allow for cell proliferation. In separate experiments, the cells were stretched for 4h and then rested for another 4 h. Samples of the medium, total cellular RNA and protein were used for analysis of collagen and TGF-beta1 gene expression and production. It was found that there was a slight increase in fibroblast proliferation at 4% and 8% stretch, compared to that of non-stretched fibroblasts, where at 8% stretch the increase was significant. It was also found that the gene expression and protein production of collagen type I and TGF-beta1 increased in a stretching-magnitude-dependent manner. And, levels of collagen type III were not changed, despite gene expression levels of the protein being slightly increased. Furthermore, the exogenous addition of anti-TGF-beta1 antibody eliminated the increase in collagen type I production under cyclic uniaxial stretching conditions. The results suggest that mechanical stretching can modulate proliferation of human tendon fibroblasts in the absence of serum and increase the cellular production of collagen type I, which is at least in part mediated by TGF-beta1.

Soluble phosphate glasses: in vitro studies using human cells of hard and soft tissue origin

This report describes the short-term response of two typical cellular components of a hard/soft tissue interface such as the periodontal ligament/mandible and patellar tendon/tibia. Tissue engineering of such interfaces requires a contiguous scaffold system with at least two cell types associated with it. Human oral osteoblasts, oral fibroblasts and hand flexor tendon fibroblasts were seeded on phosphate-based glasses of different dissolution rates. Quantitative and morphological assessment of cell adhesion and proliferation for all cell types was assessed, after first elucidating an experimental composition range using MG63 cells. In addition, immunolabelling of bone-specific non-collagenous proteins bone sialoprotein, osteonectin and osteopontin was performed to determine osteoblast phenotype. Fibroblast phenotype was established by immunolabelling for prolyl-4-hydroxylase, an enzyme vital for collagen biosynthesis. Results indicated that both cell types maintained their respective phenotypes over time in culture on glass discs of generic composition (CaO)x-(Na2O)(0.5-x)-(P2O5)0.5, remained attached and proliferated dependent on glass composition and cell type. Glasses containing at least 46 mol% CaO, produced no adverse cell reaction suggesting that these compositions that support both osteoblasts and fibroblasts would be ideal as a scaffold material for engineering the hard/soft tissue interface.

Involvement of cytochrome c release and caspase-3 activation in the oxidative stress-induced apoptosis in human tendon fibroblasts

Our previous studies have demonstrated that oxidative stress and apoptosis are involved in human tendon degeneration. The objectives of our current study were to investigate the effect of oxidative stress on human tendon cell apoptosis, and to explore pathways by which tendon cell apoptosis was induced. In vitro oxidative stress was created by exposure of cultured human rotator cuff tendon cells to H(2)O(2). Apoptotic cells were assessed by Annexin V-FITC staining and necrotic cells by propidium iodide (PI) staining using flow cytometry. Cytochrome c and caspase-3 protein expression were detected by Western blotting. A mini-dialysis unit was employed to increase the protein concentration of the cytosolic fraction. Caspase-3 activity was determined by a colorimetric assay. Tendon cell apoptosis induced by H(2)O(2) was both dose and time dependent. Addition of H(2)O(2) resulted in the release of cytochrome c to the cytosol, and an increase of caspase-3 activity and the expression of caspase-3 subunit. The data suggest that oxidative stress-induced apoptosis in human tendon fibroblasts is mediated via pathway(s) that includes release of cytochrome c from mitochondria to the cytosol and activation of caspase-3.