Platelet rich plasma in treatment of musculoskeletal pathologies

The Nrf2/HO-1 pathway participates in the antiapoptotic and anti-inflammatory effects of platelet-rich plasma in the treatment of osteoarthritis

INTRODUCTION

We aimed to explore the molecular mechanisms through which platelet-rich plasma (PRP) attenuates osteoarthritis (OA)-induced pain, apoptosis, and inflammation.

METHODS

An in vivo model of OA was established by injuring rats using the anterior cruciate ligament transection method, whereas an in vitro model was generated by exposing chondrocytes to interleukin (IL)-1β. Both models were then treated with PRP.

RESULTS

In both the in vivo and in vitro models, OA led to the suppression of the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway, whereas treatment with PRP reactivated this molecular axis. Inhibition of the Nrf2/HO-1 pathway using the Nrf2 inhibitor brusatol or through Nrf2 gene silencing counteracted the effects of PRP in reducing the tenderness and thermal pain thresholds of OA rats. Additionally, PRP reduced the mRNA expression of IL-1β, IL-6, tumor necrosis factor-alpha (TNF-α), and matrix metallopeptidase 13 (MMP-13) and the protein expression of B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X-protein (Bax), and caspase-3. Furthermore, inflammation and apoptosis were induced by brusatol treatment or Nrf2 silencing. Additionally, in the in vitro model, PRP treatment increased the proliferation of chondrocytes and attenuated their inflammatory response and apoptosis, effects that were abrogated by Nrf2 depletion.

CONCLUSIONS

The Nrf2/HO-1 pathway participates in the PRP-mediated attenuation of OA development by suppressing inflammation and apoptosis.

Regeneration of Volumetric Muscle Loss Using MSCs Encapsulated in PRP-Derived Fibrin Microbeads

Volumetric muscle loss (VML) is one of the major types of soft tissue injury frequently encountered worldwide. In case of VML, the endogenous regenerative capacity of the skeletal muscle tissue is usually not sufficient for complete healing of the damaged area resulting in permanent functional musculoskeletal impairment. Therefore, the development of new tissue engineering approaches that will enable functional skeletal muscle regeneration by overcoming the limitations of current clinical treatments for VML injuries has become a critical goal. Platelet-rich plasma (PRP) is an inexpensive and relatively effective blood product with a high concentration of platelets containing various growth factors and cytokines involved in wound healing and tissue regeneration. Due to its autologous nature, PRP has been a safe and widely used treatment option for various wound types for many years. Recently, PRP-based biomaterials have emerged as a promising approach to promote muscle tissue regeneration upon injury. This chapter describes the use of PRP-derived fibrin microbeads as a versatile encapsulation matrix for the localized delivery of mesenchymal stem cells and growth factors to treat VML using tissue engineering strategies.

Semi-Bone Tunnel Technique Using Double-Row Suture Bridge Combined With Platelet-Rich Plasma Hydrogel for Rotator Cuff Repair in a Rabbit Model

BACKGROUND

The approach to managing the footprint area and reconstructing the tendon-bone interface (TBI) is critical for optimal healing.

PURPOSE

To evaluate the outcomes of the semi-bone tunnel (SBT) technique using a double-row suture bridge combined with platelet-rich plasma (PRP) hydrogel for rotator cuff repair in a rabbit model.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 48 New Zealand White rabbits were divided into 4 groups. The supraspinatus tendons were severed at the footprint to create a rotator cuff tear model in the surgical groups. Rabbits were treated with the traditional onto-surface repair (control group), SBT technique (SBT group), and SBT technique combined with PRP hydrogel implantation (SBT+PRP group). The rabbits without surgery were the normal group. At 8 weeks after surgery, macroscopic observation, magnetic resonance imaging (MRI) and micro-computed tomography (μCT) examinations, histological evaluations, and biomechanical tests were performed to assess the curative effects of the given treatments.

RESULTS

The MRI results showed that the repaired supraspinatus tendon presented a uniform signal, minimal inflammatory response, and the lowest signal-to-noise quotient value in the SBT+PRP group. The μCT results suggested that the SBT technique did not reduce the local bone mineral density in the TBI area compared with the onto-surface repair technique. The histological staining results showed that the regenerated TBI in the SBT+PRP group had a 4-layer structure similar to the natural tissue. The highest values for biomechanical properties were observed in the SBT+PRP group, and there was no significant difference between the SBT+PRP group and normal group.

CONCLUSION

The SBT technique presented a better tendon-bone healing effect for rotator cuff tear in the rabbit model compared with the traditional onto-surface repair technique. The specimens in the SBT+PRP group had a similar TBI structure and biomechanical properties to the natural tissue.

CLINICAL RELEVANCE

The SBT technique can be an alternative surgical approach for rotator cuff repair, especially for moderate to large tears and cases requiring scaffold implantation.

Platelet-rich plasma-derived exosomes promote rotator cuff tendon-bone healing

BACKGROUND

Rotator cuff tear (RCT) is the most common type of shoulder joint injury, platelet-rich plasma-derived exosomes (PRP-exos) are highly promising in tissue repair and regeneration. The purpose of this study was to determine the function of PRP-exos in rotator cuff tendon-bone healing.

METHODS

PRP-exos were isolated from the rabbit whole blood by differential ultracentrifugation and characterized through transmission electron microscopy assay, nanoparticle tracking analysis, and western blotting. Alkaline phosphatase and Von Kossa staining were used to show tendon-derived stem cell (TDSC) differentiation. RT-qPCR and western blotting were performed to detect COL II, SOX-9, and TIMP-1. To determine the therapeutic effects of PRP-exos in vivo. Thirty New Zealand white rabbits were divided into control, model, and PRP-exos groups. The RCT animal model was constructed. The changes in tendon-bone tissue were determined by HE staining. Contents of COL-II, SOX-9, and TIMP-1 were determined by immunohistochemistry staining.

RESULTS

PRP-exos were successfully isolated from rabbit blood. PRP-exos promoted TDSC proliferation and differentiation and also induced tendon-specific markers COL II, SOX-9, and TIMP-1 production. In vivo study revealed that PRP-exos promoted early healing of injured tendons. Rabbits treated with PRP-exos had better tissue arrangement in the tear site. Additionally, the contents of COL II, SOX-9, and TIMP-1 were also increased in the RCT rabbit model after PRP-exos treatment.

CONCLUSIONS

PRP-exos enhanced tendon-bone healing by promoting TDSC proliferation and differentiation. This finding indicates that PRP-exos can serve as a promising strategy to treat rotator cuff tendon-bone healing.

The Influence of Platelet-Rich Fibrin on the Healing of Bone Defects after Harvesting Bone-Patellar Tendon-Bone Grafts

Background and Objectives: A bone-patellar tendon-bone (BTB) autograft in anterior cruciate ligament reconstruction (ACLR) is still considered the gold standard among many orthopedic surgeons, despite anterior knee pain and kneeling pain being associated with bone defects at the harvest site. Bioregenerative products could be used to treat these defects, perhaps improving both the postoperative discomfort and the overall reconstruction. Materials and methods: During a year-long period, 40 patients were enrolled in a pilot study and divided into a study group, in which bone defects were filled with Vivostat® PRF (platelet-rich fibrin), and a standard group, in which bone defects were not filled. The main outcome was a decrease in the height and width of the bone defects, as determined by magnetic resonance imaging on the control exams during the one-year follow-up. The secondary outcomes included an evaluation of kneeling pain, measured with a visual analog scale (VAS), and an evaluation of the subjective knee scores. Results: The application of Vivostat® PRF resulted in a more statistically significant reduction in the width of the defect compared with that of the standard group, especially at 8 and 12 months post operation (p < 0.05). Eight months following the surgery, the study group's anterior knee pain intensity during kneeling was statistically considerably lower than that of the standard group (p < 0.05), and the statistical difference was even more obvious (p < 0.01) at the last follow-up. Each control examination saw a significant decrease in pain intensity in both the groups, with the values at each exam being lower than those from the prior exam (p < 0.01). A comparison of subjective functional test results 12 months post operation with the preoperative ones did not prove a statistically significant difference between the groups. Conclusions: The use of Vivostat® PRF reduces kneeling pain and accelerates the narrowing of bone defects after ACLR with a BTB graft, but without confirmation of its influence on the subjective knee score.

Effect of platelet-rich plasma versus steroid injection in plantar fasciitis: a randomized clinical trial

BACKGROUND

Plantar fasciitis (PF) is a common orthopaedic problem, with heel pain worsening the quality of life. Although steroid injection is often used if the conservative treatment fails, Platelet-Rich Plasma (PRP) injection is gaining popularity due to its safety and long-lasting effect. However, the effect of PRP versus steroid injection in PF has not been studied yet in Nepal. Therefore, this study aimed to assess the effect of PRP compared with steroid injection in the treatment of PF.

METHODS

This study was a single-center, hospital-based, open-label, parallel-group randomized clinical trial to compare the effect of PRP injection with steroid injection in plantar fasciitis between August 2020 and March 2022. A total of 90 randomly selected participants aged 18 to 60 years suffering from plantar fasciitis with failed conservative treatment were intervened. The American Orthopaedic Foot and Ankle Society (AOFAS) and the Visual Analog Scale (VAS) scoring system were used to evaluate functional mobility and pain before and after the intervention for three and six months, respectively. Statistical analyses were performed using a Student's two-sample t-test. P-value < 0.05 was considered statistically significant.

RESULTS

The PRP injection showed a better outcome than the steroid injection in six months follow-up. The mean (± SD) VAS score was significantly decreased in the PRP group (1.97 + 1.13) than in the steroid group (2.71 ± 0.94) with the group difference of -0.73 (95% CI: -1.18 to -0.28) at six months. Similarly, there was a significant increase in the AOFAS scores in the PRP group (86.04 ± 7.45) compared to the steroid group (81.23 ± 9.60) at six months of follow-up with a group difference of 4.80 (95% CI: 1.15 to 8.45). There was also a significant reduction of plantar fascia thickness in the PRP group compared to that of the steroid group (3.53 ± 0.81 versus 4.58 ± 1.02) at six months of follow-up with the group difference of -1.04 (95% CI: -1.44 to -0.65).

CONCLUSION

The PRP injection showed better outcomes than steroid injection in plantar fasciitis treatment over the course of six months. Further research with a larger population and longer follow-up than six months is needed to generalize the findings and their long-term efficacy.

TRIAL REGISTRATION

NCT04985396. First registered on 02 August 2021. ( https://clinicaltrials.gov/ct2/show/NCT04985396 ).

Failure to disclose industry funding impacts outcomes in randomized controlled trials of platelet-rich plasma

PURPOSE

Platelet-rich plasma (PRP) represents a highly profitable biological therapy. Platelet-rich plasma is widely used to treat musculoskeletal disorders despite mixed evidence of its efficacy. As evidenced by literature from other domains, industry funding may influence the results of clinical trials. The objective of the current study was to determine the association between industry funding and positive results for randomized controlled trials (RCTs) assessing the efficacy of PRP in musculoskeletal disorders.

METHODS

A search of four databases was conducted. Included studies were RCTs comparing PRP to any non-PRP comparator in adults (18 years old or over) with musculoskeletal disorders and had full text available in English. Studies were excluded if they were published before 2016 or were non-human trials. A multivariate binomial logistic regression model was created to explore predictors of statistically significant findings. Covariates included the presence of industry funding, sample size, and length of study follow-up. 1440 records were screened with 87 trials included in the final analysis.

RESULTS

Of the 87 studies, 61 (70%) reported a statistically significant primary outcome. The presence of industry funding was not predictive of a statistically significant primary outcome [OR = 0.36, 95% CI 0.096-1.36, (n.s.)]. Studies that did not state whether industry funding was present had a higher chance of reporting a statistically significant primary outcome (OR = 3.61, 95% CI 1.1-11.9, p = 0.035). Sample size and length of follow-up were not predictive of a statistically significant primary outcome.

CONCLUSION

The results of the current study conclude that industry funding had no impact on the reporting of positive results for RCTs investigating PRP in musculoskeletal disorders. However, not disclosing sources of funding was associated with a higher likelihood of reporting positive results. The results of trials that fail to disclose funding sources should be interpreted with caution in the PRP literature.

LEVEL OF EVIDENCE

I.

Strategies for promoting tendon-bone healing: Current status and prospects

Tendon-bone insertion (TBI) injuries are common, primarily involving the rotator cuff (RC) and anterior cruciate ligament (ACL). At present, repair surgery and reconstructive surgery are the main treatments, and the main factor determining the curative effect of surgery is postoperative tendon-bone healing, which requires the stable combination of the transplanted tendon and the bone tunnel to ensure the stability of the joint. Fibrocartilage and bone formation are the main physiological processes in the bone marrow tract. Therefore, therapeutic measures conducive to these processes are likely to be applied clinically to promote tendon-bone healing. In recent years, biomaterials and compounds, stem cells, cell factors, platelet-rich plasma, exosomes, physical therapy, and other technologies have been widely used in the study of promoting tendon-bone healing. This review provides a comprehensive summary of strategies used to promote tendon-bone healing and analyses relevant preclinical and clinical studies. The potential application value of these strategies in promoting tendon-bone healing was also discussed.

Histopathological Evaluation of Platelet-Rich Plasma Effect in Acute Tympanic Membrane Perforation

Platelet-rich plasma (PRP) is a reliable and has low side-effect profile and has beneficial effects on wound healing. Its investigatory effects on wound-healing process were shown on various tissues. This study aims to investigate PRP's local application effects to perforated rat TM in terms of healing and histopatological outcomes. Twenty-two Wistar rats were used in the study. The rats' ears were examined with a pediatric endoscope (2.7 mm, 0°), and the TM posterior quadrant of their right ear was perforated with a 20-gauge needle. After this procedure, the rats were divided into two equal groups. A spongel with PRP was applied on the perforated TM in the first group, and spongel with standard saline solution was applied on the second group. Following the sacrifice, the middle air bullas were carefully dissected and removed for histopathological examination. Hematoxylin eosin (for fibroblasts, lymphocyte, collagen fibers) and immunohistochemical staining were done for epithelial growth factor receptor (EGFR), fibroblast growth factor receptor (FGFR1), and vascular endothelial growth factor (VEGF) staining for histopathologic examinations. There was not a significant difference between the two groups for lymphocyte. There was a significant difference between control and study groups for collagen and EGFR (P < 0.05). Although the mean value of FGF- and VEGF-positive cells was higher in the study group than in the control group, the difference was not significant (P > 0.05). PRP is an effective autologous material for the healing process of acute TM perforations in a rat model, as demonstrated in the present study. We think that the use of PRP for acute TM perforations can have a positive effect on the healing process by increasing the level of growth factors, especially EGFR. In addition, an increase in collagen can also have a positive effect on healing.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-021-02912-2.

Clinical and Functional Outcome of Meniscal Injuries Treated with Platelet-Rich Plasma: A Single-Center Case Series

Meniscal injuries are among the most frequently encountered conditions in the knee joint. Therapeutic approaches are diverse and are largely dependent on the extent and location of the injury. The purpose of this study was to describe the clinical and functional outcomes of an intraarticular and percutaneous platelet-rich plasma (PRP) injection regime in patients with stable meniscal injuries. Demographics, the type of tear, affected knee, surgical procedure, type of intervention, follow-up period, and outcomes were recorded in all cases. Patient-reported outcome measures included the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Tegner activity level scale. Overall patient satisfaction, quality of life, and pain intensity were also assessed. A total of 38 cases (8 females) had sustained a stable meniscal lesion (32 medial, 6 lateral) and met the inclusion criteria. All of them received three intraarticular and percutaneous PRP injections. Patients receiving the PRP injection regime reported clinically (p = 0.000) and functionally (p = 0.000 and p = 0.001) significant improvement in all outcome measures during this interval. All patients reported they were very satisfied or satisfied with the outcome. The results of this study suggest that the treatment of stable meniscal injuries with percutaneous-intraarticular PRP injections can achieve a significant clinical and functional improvement.

Ultrasound-guided injection of platelet-rich plasma or cord blood platelet-rich plasma in nonunion: a randomized controlled trial

Aim: To compare the ability of autologous platelet-rich plasma (PRP) and cord blood PRP (PRPc) to accelerate bone healing. Patients & methods: 71 patients with mechanically stable nonunion were treated weekly (3 consecutive weeks) with ultrasound-guided percutaneous injections of PRP or PRPc in a controlled randomized clinical trial. The primary outcome was healing (12 months) and secondary outcomes were radiological evolution (2 and 6 months) and changes in pain intensity (6 months). Results & conclusion: Bone consolidation was assessed over time without significant differences between PRP and PRPc treatment. In patients with persistent nonunion, pain perception decreased more after PRP treatment. PRPc appears to be a valid alternative when specific clinical conditions suggest avoiding the use of autologous blood products.

Intracavernous Injection of Platelet-Rich Plasma Therapy Enhances Erectile Function and Decreases the Mortality Rate in Streptozotocin-Induced Diabetic Rats

Erectile dysfunction (ED) is an agonizing complication of diabetes mellitus (DM) and it is challenging to treat ED in DM patients. Platelet-rich plasma (PRP) is a unique therapeutic strategy comprising intrinsic growth factors. An attempt was made to explore the potentiality of the PRP treatment in DM-induced ED rats in various groups (control, DM-non-ED, DM-ED, and DM-ED treated with PRP). Streptozotocin (STZ) was used to induce DM in rats. The blood glucose levels of the DM rats were maintained at >300 mg/dl. In the 18-week experiment, survival rate, body weight, intracavernous pressure (ICP) variations, and arterial blood pressure were analyzed. The tissue restoration results were validated by histological, immunofluorescence, and transmission electron microscopic analysis. PRP treatment of DM-ED rats significantly increased all parameters of erectile function compared to pre-treatment of PRP and DM-ED treated with vehicle. The histological results revealed that PRP treatment substantially enhanced the regeneration of myelinated nerves and decreased the atrophy of corporal smooth muscle. Notably, the PRP treatment immensely enhanced the survival rate in post-surgery DM-ED rats. These results indicated certain benefits of PRP treatment in delaying damage and preventing post-surgery complications in DM patients. Hence, PRP treatment is a novel multifactorial strategy for DM-ED patients.

Effects of Platelet-Rich Plasma on Clinical Outcomes After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis

Background:

Many studies have documented the use of platelet-rich plasma (PRP) alongside anterior cruciate ligament (ACL) reconstruction (ACLR) in the management of ACL injury, but evidence on the benefits of PRP in improving the clinical outcomes of ACLR is inconsistent.

Purpose:

To help in our understanding, we undertook a systematic review and meta-analysis of randomized controlled trials (RCTs) that evaluated the effects of PRP on patient-reported functional scores, the clinical assessments of knee function and structure, and complications.

Study Design:

Systematic review; Level of evidence, 1.

Methods:

We searched 9 online databases for RCTs published in English or Chinese that examined the effects of PRP on ACLR. The primary outcome measures were visual analog scale (VAS) for pain and International Knee Documentation Committee (IKDC) scores. The secondary outcomes included KT-1000 arthrometer, pivot-shift test, Lysholm and Tegner scores, tunnel widening, graft characterization, and complications. Subgroup analyses were performed according to time of assessments. Fixed- and random-effects models were selected for data analysis.

Results:

A total of 14 studies were included. When PRP was injected to graft tunnels, the pooled VAS scores of the 2 groups were similar (P = .31), and the subgroup analysis found that VAS and IKDC only improved at 3 months postoperatively (P = .0003 and P < .00001, respectively). When PRP was used at the bone–patellar tendon–bone harvest sites, VAS was decreased in the first 6 months postoperatively (P < .00001), whereas IKDC score was not remarkably different (P = .07). After PRP injection, Lysholm scores at 3 months postoperatively was different between the 2 groups (P < .00001), but the Tegner scores (P = .86), KT-1000 measurements (P = .12), the positive rate of pivot-shift test (P = .64), the enlargement of tunnels (femoral, P = .91; tibial, P = .80), and the characterization of grafts (P = .05) were not different. No difference in complications was found in either group.

Conclusion:

PRP applied alongside ACLR could reduce postoperative pain and improve knee function in the short and medium terms but is ineffective in the long term. PRP does not improve knee stability and the enlargement of tunnels and does not accelerate the healing of grafts. Further studies would be required.

Platelet-Rich Plasma for Rheumatoid Arthritis: A Case Series

Rheumatoid Arthritis (RA) is a chronic disease characterized by severe inflammation that leads to degradation of articular cartilage and the formation of bony erosions. Currently, certain anesthesiologist-led pain management clinics have begun to take on a collaborative role in the treatment of patients with RA, as this progressive disease impairs work capacity due to chronic pain. We present three clinical cases in which platelet-rich plasma (PRP) was used for the treatment of RA in patients seeking a new therapy for pain control and improved range of motion, specifically in certain joints of the hand. The Patient Activity Scale II was employed as a standardized method to assess RA disease severity, recorded on the day of injection, at one month, at three months, and at six months. All of the included patients, ages 49, 60, and 63, had an established diagnosis of RA affecting the proximal interphalangeal and metacarpophalangeal joints of the hand. Over the course of six months, two out of three patients reported a 20% reduction in pain from the initial visit and a 30% improvement in overall well-being. The third patient noted a 50% decrease in pain from the initial visit and a 50% improvement in overall well-being. PRP treatment consistently resulted in functional improvement for each of the three patients treated, while also reducing long term pain and inflammation. Initial clinical and laboratory studies have shown that autologous plasma rich in platelets serves as a source of an abundance of growth factors once activated. The multitude of these growth factors injected into and around the diseased joints improves functionality in patients with RA indicating PRP may be a safe and beneficial therapy in patients with RA primarily affecting the joints of the hand.

Head and Neck Restoration in Scar Alopecia: Hair Transplantation in Scalp, Eyebrows, Beard and Mustache

BACKGROUND

Surgical management of hair loss has become an increasingly challenging procedure, when dealing with scar alopecia. We investigated the efficacy of hair transplantation in patients with head and neck scar alopecia.

METHODS

From 2016 to 2018 in Shiraz, Iran, all patients with scar alopecia in head and neck were evaluated for efficacy of follicular unit extraction (FUE), follicular unit transplantation (FUT) or a combination of two methods from donor sites in scalp and beard various hair-grafts were compared.

RESULTS

Fifty-six patients were enrolled. Most of them were between 31 and 40 yr old (48.3%) and male (71.4%). Trauma, burn, surgical excision of adjacent skin, radiotherapy and leishmaniasis were the registered causes. Scars were visible in scalp (39.3%), beard (28.6%), eyebrow (21.4%), and moustache (10.7%) regions. FUE (87.5%), FUT (10.7%) and a combination (1.8%) were the used methods. One-hair-grafts were used in eyebrows (100%), moustache (100%), beard (88%) and scalp (7.9%), while 2-hair-grafts in beard (6%) and scalp (47.4%) and 3-haired grafts in beard (6%) and scalp (44.7%) transplantations.

CONCLUSION

In head and neck scar alopecia, hair transplantation was selected based on type and depth of scar. FUE was targeted when huge grafts were not needed, including beard, moustache, and eyebrow, while FIT was used when extensive scars were present in scalp. One-hair-grafts were mostly applied for eyebrow, moustache and beard, 2-hair- and 3-hair- grafts for beard and scalp transplantation. These findings can be added to the literature when FUE, FIT, or their combination are targeted in hair restoration of scar alopecia in head and neck.

Combination of graphene oxide and platelet-rich plasma improves tendon-bone healing in a rabbit model of supraspinatus tendon reconstruction

The treatment of rotator cuff tear is one of the major challenges for orthopedic surgeons. The key to treatment is the reconstruction of the tendon-bone interface (TBI). Autologous platelet-rich plasma (PRP) is used as a therapeutic agent to accelerate the healing of tendons, as it contains a variety of growth factors and is easy to prepare. Graphene oxide (GO) is known to improve the physical properties of biomaterials and promote tissue repair. In this study, PRP gels containing various concentrations of GO were prepared to promote TBI healing and supraspinatus tendon reconstruction in a rabbit model. The incorporation of GO improved the ultrastructure and mechanical properties of the PRP gels. The gels containing 0.5 mg/ml GO (0.5 GO/PRP) continuously released transforming growth factor-β1 (TGF-β1) and platelet-derived growth factor (PDGF)-AB, and the released TGF-β1 and PDGF-AB were still at high concentrations, ∼1063.451 pg/ml and ∼814.217 pg/ml, respectively, on the 14th day. In vitro assays showed that the 0.5 GO/PRP gels had good biocompatibility and promoted bone marrow mesenchymal stem cells proliferation and osteogenic and chondrogenic differentiation. After 12 weeks of implantation, the magnetic resonance imaging, micro-computed tomography and histological results indicated that the newly regenerated tendons in the 0.5 GO/PRP group had a similar structure to natural tendons. Moreover, the biomechanical results showed that the newly formed tendons in the 0.5 GO/PRP group had better biomechanical properties compared to those in the other groups, and had more stable TBI tissue. Therefore, the combination of PRP and GO has the potential to be a powerful advancement in the treatment of rotator cuff injuries.

The Emerging Role on the Use of Platelet-Rich Plasma Products in the Management of Urogynaecological Disorders

Background: The regenerative efficacy of platelet-derived products has been recently investigated in the treatment of pelvic floor disorders (PFDs). We aimed to synthesize the current evidence of platelet-rich plasma (PRP) products used in urogynaecological disorders including vaginal atrophy, pelvic organ prolapse (POP), urinary incontinence, vaginal fistulas and vaginal mesh exposure. Methods: A meticulous search of the currently available literature on the use of PRP for the management of PFDs was performed using 3 electronic databases. Results: PRP could be a feasible alternative modality for the management of vaginal atrophy with favourable outcomes in vaginal atrophy parameters and patients' satisfaction, especially when hormone therapy is contraindicated. In patients with POP, an increase in collagen concentration after PRP application was observed while the use of PRP resulted in improvement of stress urinary incontinence symptoms. A considerable proportion of vesicovaginal fistulas were treated after application of PRP-based injections. Conclusions: There is only limited evidence of the use of PRP for PFDs. Platelet-rich plasma appears to be a promising, easy to apply, cost-effective and feasible alternative therapeutic modality for the management of various urogynaecological disorders. Future randomized trials are needed to confirm the efficacy of PRP in the treatment of urogynaecological disorders.

Nanomechanical Properties of Articular Cartilage Due to the PRP Injection in Experimental Osteoarthritis in Rabbits

The purpose of this study was twofold. Firstly, we proposed a measurement protocol for the atomic force microscopy (AFM) method to determine the nanomechanical properties of articular cartilage in experimental osteoarthritis in rabbits. Then, we verified if mechanical properties can be evaluated with AFM shortly after platelet-rich plasma (PRP) injection. We hypothesized that the modulus determined by AFM indentation experiments could be utilized as a progressive disease marker during the treatment of osteoarthritis. The rabbits were equally divided into three groups of six: control (group 1); injections of saline (0.5 mL) and 10% surgical talc (Talcum Pharmaceutical^®, Minsk, Belarus) were delivered into the right knee under the patella (group 2 and 3); and PRP was injected into the right knee (group 3). In group 2, the arithmetic average of absolute values (Ra) change was a 25% increase; the maximum peak height (Rp) increased by over 102%, while the mean spacing between local peaks (S) increased by 28% (p < 0.05). In group 3, Ra increased by 14% and Rp increased by 32%, while S decreased by 75% (p < 0.05). The Young’s modulus of the surface layers decreased by 18% as a result of induced model of osteoarthritis (IMO) (p < 0.05), and it increased by 9% (p < 0.05) as a result of PRP therapy, which means that the mechanical properties of cartilage were partially recovered. This research demonstrates that Young’s modulus utilized on a nanometer scale has potential to be a progressive disease marker during the treatment of osteoarthritis.

Platelet-derived bio-products: Classification update, applications, concerns and new perspectives

Platelet derived bio-products in the form of platelet rich plasma, plasma rich in growth factors, or plasma-free platelet releasates, are being studied worldwide with the aim of proving their efficacy in tissue regeneration within many different clinical areas, such as traumatology, maxillofacial surgery, ophthalmology, dermatology and otorhinolaryngology, amongst others. The current lack of consensus in the preparation method and application form, or in the quality assessment of each bio-product, precludes adequate interpretation of the relevance of reported clinical outcomes, and, while many in clinicians are very positive about them, many are sceptic. Relevant aspects of these products are considered to propose a classification nomenclature which would aid a comprehensive comparison of clinical outcomes of bio-products of the same characteristics. Finally, the uses of platelet-derived bio-products in in vitro culture (for cell therapy purposes) as a substitute of animal-origin sera, and other future perspectives of applications of platelet-derived bio-products are discussed.