Platelet Rich Plasma and Hyaluronic Acid Blend for the Treatment of Osteoarthritis: Rheological and Biological Evaluation

Mechanisms and applications of the regenerative capacity of platelets-based therapy in knee osteoarthritis

Osteoarthritis (OA) is the most prevalent joint disease in the elderly population and its substantial morbidity and disability impose a heavy economic burden on patients and society. Knee osteoarthritis (KOA) is the most common subtype of OA, which is characterized by damage to progressive articular cartilage, synovitis, and subchondral bone sclerosis. Most current treatments for OA are palliative, primarily aim at symptom management, and do not prevent the progression of the disease or restore degraded cartilage. The activation of α-granules in platelets releases various growth factors that are involved in multiple stages of tissue repair, suggesting potential for disease modification. In recent years, platelet-based therapies, such as platelet-rich plasma, platelet-rich fibrin, and platelet lysates, have emerged as promising regenerative treatments for KOA, but their related effects and mechanisms are still unclear. Therefore, this review aims to summarize the biological characteristics and functions of platelets, classify the products of platelet-based therapy and related preparation methods. Moreover, we summarize the basic research of platelet-based regeneration strategies for KOA and discuss the cellular effects and molecular mechanisms. Further, we describe the general clinical application of platelet-based therapy in the treatment of KOA and the results of the meta-analysis of randomized controlled trials.

The bioengineering application of hyaluronic acid in tissue regeneration and repair

The multifaceted role of hyaluronic acid (HA) across diverse biomedical disciplines underscores its versatility in tissue regeneration and repair. HA hydrogels employ different crosslinking including chemical (chitosan, collagen), photo- initiation (riboflavin, LAP), enzymatic (HRP/H2O2), and physical interactions (hydrogen bonds, metal coordination). In biophysics and biochemistry, HA's signaling pathways, primarily through CD44 and RHAMM receptors, modulate cell behavior (cell migration; internalization of HA), inflammation, and wound healing. Particularly, smaller HA fragments stimulate inflammatory responses through toll-like receptors, impacting macrophages and cytokine expression. HA's implications in oncology highlight its involvement in tumor progression, metastasis, and treatment. Elevated HA in tumor stroma impacts apoptosis resistance and promotes tumor growth, presenting potential therapeutic targets to halt tumor progression. In orthopedics, HA's presence in synovial fluid aids in osteoarthritis management, as its supplementation alleviates pain, enhances synovial fluid's viscoelastic properties, and promotes cartilage integrity. In ophthalmology, HA's application in dry eye syndrome addresses symptoms by moisturizing the eyes, replenishing tear film deficiencies, and facilitating wound healing. Intravitreal injections and hydrogel-based systems offer versatile approaches for drug delivery and vitreous humor replacement. For skin regeneration and wound healing, HA hydrogel dressings exhibit exceptional properties by promoting moist wound healing and facilitating tissue repair. Integration of advanced regenerative tools like stem cells and solubilized amnion membranes into HA-based systems accelerates wound closure and tissue recovery. Overall, HA's unique properties and interactions render it a promising candidate across diverse biomedical domains, showcasing immense potentials in tissue regeneration and therapeutic interventions. Nevertheless, many detailed cellular and molecular mechanisms of HA and its applications remain unexplored and warrant further investigation.

Adductor longus and brevis lesion in an amateur soccer player: platelet rich plasma and multifractioned hyaluronic acid injections to enhance clinical recovery

Groin pain is a common issue in athletes, with a particularly high incidence in male soccer players. Adductor muscles are the most involved site of the groin, accounting for up to one-fourth of muscle injuries of that region. Physical therapy and rehabilitation programs for adductor-related groin pain using active exercises are effective in getting athletes back to sport. However, the return-to-play time varies according to the injury severity. Minor lesions can recover in 1-2 weeks, while severer injuries require 8-12 weeks. To enhance tendon healing and shorten the return to play time, intrandentinous injections of Platelet Rich Plasma (PRP) have been proposed. An increasing body of evidence in literature have shown efficacy of platelet rich plasma in aiding the healing process in tendinopathies. Similarly, more recent evidences have proven hyaluronic (HA) acid to have anti-inflammatory, proliferative, repairing, and analgesic effects. This case report presents the clinical application of combined PRP and a multifractioned (a mixture of different molecular weights) HA in a 24-year-old athlete suffering from a hip adductor rupture.

Hyaluronic Acid-Based Injective Medical Devices: In Vitro Characterization of Novel Formulations Containing Biofermentative Unsulfated Chondroitin or Extractive Sulfated One with Cyclodextrins

Currently, chondroitin sulfate (CS) and hyaluronic acid (HA) pharma-grade forms are used for osteoarthritis (OA) management, CS as an oral formulations component, and HA as intra-articular injective medical devices. Recently, unsulfated chondroitin, obtained through biofermentative (BC) manufacturing, has been proposed for thermally stabilized injective preparation with HA. This study aimed to highlight the specific properties of two commercial injective medical devices, one based on HA/BC complexes and the other containing HA, extractive CS, and cyclodextrins, in order to provide valuable information for joint disease treatments. Their biophysical and biomechanical features were assayed; in addition, biological tests were performed on human pathological chondrocytes. Rheological measurements displayed similar behavior, with a slightly higher G' for HA/BC, which also proved superior stability to the hyaluronidase attack. Both samples reduced the expression of specific OA-related biomarkers such as NF-kB, interleukin 6 (IL-6), and metalloprotease-13 (MMP-13). Moreover, HA/BC better ensured chondrocyte phenotype maintenance by up-regulating collagen type 2A1 (COLII) and aggrecan (AGN). Notwithstanding, the similarity of biomolecule components, the manufacturing process, raw materials characteristics, and specific concentration resulted in affecting the biomechanical and, more interestingly, the biochemical properties, suggesting potential better performances of HA/BC in joint disease treatment.

Enhancing Pain Relief in Temporomandibular Joint Arthrocentesis: Platelet-Rich Plasma and Hyaluronic Acid Synergy

Temporomandibular joint (TMJ) disorders present complex challenges in pain management and functional restoration. This review delves into the innovative approach of using platelet-rich plasma (PRP) and hyaluronic acid (HA) combination therapy in TMJ arthrocentesis to address these issues. The potential benefits of this approach are highlighted through an exploration of mechanisms, clinical studies, safety considerations, and future directions. PRP's regenerative properties and HA's lubrication and anti-inflammatory effects offer a comprehensive solution to multifactorial TMJ pain and dysfunction. Clinical studies reveal significant pain reduction, improved mobility, and enhanced satisfaction in patients treated with PRP and HA. Although mild and transient adverse effects have been reported, the safety profile remains favorable. While the evidence is promising, more extensive randomized controlled trials are needed to establish sustained efficacy and safety. As research evolves, collaborative efforts among clinicians and researchers are crucial in realizing the potential of PRP and HA combination therapy, ultimately providing a novel pathway to alleviate TMJ-related pain and enhance patient well-being.

A Review of Recent Innovations in Cartilage Regeneration Strategies for the Treatment of Primary Osteoarthritis of the Knee: Intra-articular Injections

Background

The pathology of primary osteoarthritis (OA) begins with structural cartilage damage, which initiates a self-propagating inflammatory pathway that further exacerbates cartilage deterioration. Current standard of care for knee primary OA involves treating the inflammatory symptoms to manage pain, which includes intra-articular (IA) injections of cortisone, an anti-inflammatory steroid, followed by a series of joint-cushioning hyaluronic acid gel injections. However, these injections do not delay the progression of primary OA. More focus on the underlying cellular pathology of OA has prompted researchers to develop treatments targeting the biochemical mechanisms of cartilage degradation.

Purpose

Researchers have yet to develop a United States Food and Drug Administration (FDA)-approved injection that has been demonstrated to significantly regenerate damaged articular cartilage. This paper reviews the current research on experimental injections aimed at achieving cellular restoration of the hyaline cartilage tissue of the knee joint.

Study Design

Narrative review.

Methods

The authors conducted a narrative literature review examining studies on primary OA pathogenesis and a systematic review of non-FDA-approved IA injections for the treatment of primary OA of the knee, described as "disease-modifying osteoarthritis drugs" in phase 1, 2, and 3 clinical trials.

Conclusion

New treatment approaches for primary OA investigate the potential of genetic therapies to restore native cartilage. It is clear that the most promising IA injections that could improve treatment of primary OA are bioengineered advanced-delivery steroid-hydrogel preparations, ex vivo expanded allogeneic stem cell injections, genetically engineered chondrocyte injections, recombinant fibroblast growth factor therapy, injections of selective proteinase inhibitors, senolytic therapy via injections, injectable antioxidant therapies, injections of Wnt pathway inhibitors, injections of nuclear factor-kappa β inhibitors, injections of modified human angiopoietin-like-3, various potential viral vector-based genetic therapy approaches, and RNA genetic technology administered via injections.

Japanese Laws and the Current Status of Regenerative Medicine in the Tohoku Region

AIM

The aim of this study was to review Japanese laws regarding regenerative medicine and the current status of clinical application of regenerative medicine, to learn about the advantages and problems, and to thereby serve as a reference for measures necessary for the development of regenerative medicine.

BACKGROUND

Regenerative medicine started in 1957 with the transplantation of hematopoietic stem cells, followed by the establishment of embryonic stem cells in 1981 and induced pluripotent stem cells in 2006, and continues to evolve progressively. At the same time, however, problems have emerged due to lax legal regulations, such as the use of treatments that lack scientific evidence.

REVIEW RESULTS

The Japanese government enacted two laws to regulate regenerative medicine: the Law to Ensure the Safety of Regenerative Medicine and the Amend the Pharmaceutical Affairs Law in 2013. These laws were enacted with the aim of providing safe regenerative medicine promptly and smoothly and developing many regenerative medicine products. In these laws, regenerative medicine is defined as medical treatment that restores lost functions of damaged organs and tissues with the help of cellular and tissue-based products. Nowadays, there are two major methods of regenerative medicine. One representative method involves the transplantation of devices that activates self-regenerative ability by introducing living cells into patients' body. The other method is the activation and differentiation of endogenous stem cells with cell growth and differentiation factors.

CONCLUSION

The current status of regenerative medicine in the Tohoku region after the enactment of these laws is described in detail. This clarified the advantages and disadvantages associated with regenerative medicine as it is currently practiced in Japan.

CLINICAL SIGNIFICANCE

Development of regenerative medicine in dentistry will be advanced by learning about its clinical application in medicine.

Platelet-Rich Plasma Gel Matrix (PRP-GM): Description of a New Technique

Several musculoskeletal conditions are triggered by inflammatory processes that occur along with imbalances between anabolic and catabolic events. Platelet-rich plasma (PRP) is an autologous product derived from peripheral blood with inherent immunomodulatory and anabolic properties. The clinical efficacy of PRP has been evaluated in several musculoskeletal conditions, including osteoarthritis, tendinopathy, and osteonecrosis. When used in combination with hyaluronic acid (HA), a common treatment alternative, the regenerative properties of PRP are significantly enhanced and may provide additional benefits in terms of clinical outcomes. Recently, a new PRP-derived product has been reported in the literature and is being referred to as "plasma gel". Plasma gels are obtained by polymerizing plasmatic proteins, which form solid thermal aggregates cross-linked with fibrin networks. Plasma gels are considered to be a rich source of growth factors and provide chemotactic, migratory, and proliferative properties. Additionally, clot formation and the associated fibrinolytic reactions play an additional role in tissue repair. There are only a few scientific articles focusing on plasma gels. Historically, they have been utilized in the fields of aesthetics and dentistry. Given that the combination of three products (PRP, HA, and plasma gel) could enhance tissue repair and wound healing, in this technical note, we propose a novel regenerative approach, named "PRP-HA cellular gel matrix" (PRP-GM), in which leukocyte-rich PRP (LR-PRP) is mixed with a plasma gel (obtained by heating the plasma up) and HA in one syringe using a three-way stopcock. The final product contains a fibrin-albumin network entangled with HA's polymers, in which the cells and biomolecules derived from PRP are attached and released gradually as fibrinolytic reactions and hyaluronic acid degradation occur. The presence of leukocytes, especially monocytes and macrophages, promotes tissue regeneration, as type 2 macrophages (M2) possess an anti-inflammatory feature. In addition, HA promotes the viscosuplementation of the joint and induces an anti-inflammatory response, resulting in pain relief. This unique combination of biological molecules may contribute to the optimization of regenerative protocols suitable for the treatment of degenerative musculoskeletal diseases.

Assessment of the effectiveness and satisfaction of platelet-rich plasma compared with hyaluronic acid in knee osteoarthritis at minimum 7-year follow-up: A post hoc analysis of a randomized controlled trial

Background: Knee osteoarthritis (KOA) can be effectively treated conservatively using platelet-rich plasma (PRP) injections into the affected joints. While the short-term therapeutic clinical benefits were well documented, the mid-term results remain undetermined. To clarify its efficacy, the mid-term clinical outcomes of intra-articular injections of either PRP or hyaluronic acid (HA) in KOA were compared. Methods: One hundred patients who complied with the inclusion criteria were randomized to undergo once a week 3 weeks, intra-articular injections of either PRP or HA. Patients were evaluated before the injection, at 3, 6, and a mean of 78.9 months of follow-up. Eighty-five patients reached the final evaluation. Data on survival, re-intervention, pain, function, imaging, and satisfaction were collected and analyzed. Results: With surgery for any reason as the endpoint, the cumulative survival rate of the PRP group was 90%, while that of the HA group was 74%. There was a significant difference between the two groups in the total re-intervention rate (56.7% vs 16.2%, p < 0.05). The comparative analyses showed significant intergroup differences in the visual analog scale (VAS) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) (p < 0.01, p < 0.05, respectively) at the final follow-up. And base on the regression analyses, the type of treatment, age, and Kellgren-Lawrence (K-L) grade served as statistically an independent determinants of VAS (p < 0.001, p = 0.034, p < 0.001, respectively). Likewise, those variables independently determined WOMAC in our study. However, no difference was observed in the imaging evaluation, containing the K-L grade and Cartilage Lesion Score, between the two groups (p > 0.05). Besides, the satisfaction treated by the PRP was 78.6%, with a superiority compared with HA (55.8%, p < 0.05), and no complications were noted in the whole treatment process among patients who participated. Conclusion: PRP was more effective than HA in survival and re-intervention rates, VAS, and WOMAC, although there were no significant differences in the imaging evaluation between the two groups. Furthermore, patients treated with PRP were associated with higher satisfaction compared with HA.

Efficacy of a Novel Intra-Articular Administration of Platelet-Rich Plasma One-Week Prior to Hyaluronic Acid versus Platelet-Rich Plasma Alone in Knee Osteoarthritis: A Prospective, Randomized, Double-Blind, Controlled Trial

Recent studies have suggested that the combined injection of platelet-rich plasma (PRP) and hyaluronic acid (HA) may have additive benefits for knee osteoarthritis over PRP alone, but there is insufficient evidence to support this combined injection. Moreover, the simultaneous injection of PRP and HA may offset the combined effect. Hence, the aim of this prospective, randomized, double-blind study was to assess their combined efficacy with a novel injection protocol. Forty-six study subjects with unilateral knee osteoarthritis were randomized to receive either a single-dose injection of HA (intervention group) or normal saline (control group) 1 week after a single-dose injection of leukocyte-poor PRP. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and static balance and the risk of falls measured by Biodex Balance System were, respectively, the primary and secondary outcome measures. Evaluations were performed at baseline, 1 month, 3 months, 6 months, and 12 months post-injection. The intervention group exhibited significant declines in WOMAC pain, stiffness, and total scores, as well as static balance, compared to the control group (p < 0.05). These randomized double-blind control trials, with novel protocol of intra-articular injection of PRP 1-week prior to HA, provide greater symptom relief and improve static balance compared to PRP alone in patients with knee osteoarthritis.

Assessment of Characteristics and Methodological Quality of the Top 50 Most Cited Articles on Platelet-Rich Plasma in Musculoskeletal Medicine

Background:

The wide range of clinical applications and controversial scientific evidence associated with platelet-rich plasma (PRP) therapy in musculoskeletal medicine requires an examination of the most commonly cited studies within this field.

Purpose:

To identify the 50 most cited articles on PRP, assess their study design, and determine any correlations between the number of citations and level of evidence (LoE) or methodological quality.

Study Design:

Cross-sectional study.

Methods:

The Web of Science database was queried to identify the top 50 most cited articles on PRP in orthopaedic surgery. Bibliometric characteristics, number of citations, and LoE were recorded. Methodological quality was evaluated using the Modified Coleman Methodology Score (MCMS), Methodological Index for Non-randomized Studies (MINORS), and Minimum Information for Studies Evaluating Biologics in Orthopaedics (MIBO). The Pearson correlation coefficient and Spearman correlation coefficient (r_S) were used to determine the degree of correlation between the number of citations or citation density and LoE, MCMS, MINORS score, and MIBO score. Student t tests were performed for 2-group comparisons.

Results:

The top 50 articles were published between 2005 and 2016 in 21 journals. The mean number of citations and citation density were 241 ± 94 (range, 151-625) and 23 ± 8, respectively, and the mean LoE was 2.44 ± 1.67, with 15 studies classified as LoE 1. The mean MCMS, MINORS score, and MIBO score were 66.9 ± 12.6, 16 ± 4.7, and 12.4 ± 3.7, respectively. No correlation was observed between the number of citations or citation density and LoE, MCMS, MINORS score, and MIBO score. A significant difference (P = .02) was noted in LoE in articles from the United States (3.56 ± 1.7) versus outside the United States (2 ± 1.5). Seven of the 8 in vivo studies were published between 2005 and 2010, whereas 19 of the 25 clinical outcome investigations were published between 2011 and 2016. Studies that were published more recently were found to significantly correlate with number of citations (r_S = –0.38; P = .01), citation density (r_S = 0.36; P = .01), and higher LoE (r_S = 0.47; P = .01).

Conclusion:

The top 50 most cited articles on PRP consisted of high LoE and fair methodological quality. There was a temporal shift in research from in vivo animal studies toward investigations focused on clinical outcomes.

Thermal Oscillation Changes the Liquid-Form Autologous Platelet-Rich Plasma into Paste-Like Form

Objectives

The texture of the autologous platelet-rich plasma (PRP) that is used in treating degenerative joint diseases such as knee osteoarthritis (OA) is usually in liquid form. However, the turnover rate of protein metabolism in the knee synovial fluid (SF) is less than one hour. This study examined the feasibility of the thermal oscillation technique in converting the liquid-form PRP into an injectable viscous paste-like PRP that may delay the degradation of PRP and continuously release growth factors in the knee joint for a longer period of time.

Methods

This study was conducted in the rehabilitation department of a tertiary hospital. A total of 10 elderly patients with an average age of greater than 65 years and diagnosed with moderate degree of knee OA were recruited. The RegenPRP (RegenLab, Le Mont-sur-Lausanne, Switzerland) test tube chamber was used for PRP generation. A total of 60 milliliters (mL) of blood was drawn from each patient. 10 mL of blood was injected into each PRP test tube chamber. As a result, a total of 6 test tube chambers were obtained and each chamber was centrifuged for 15 minutes. Approximately 5 mL of PRP supernatant (the liquid-form end product) was aspirated and sent for thermal oscillation treatment. Five temperatures were tested: 55, 65, 75, 85, and 95 degrees Celsius. Oscillation was set at 200 revolutions per minute (rpm) for 15 minutes. The enzyme-linked immunosorbent assay (ELISA) was applied in measuring the concentration of platelet-derived growth factor (PDGF) in picogram/milliliter (pg/mL). Repeated measures ANOVA followed by the Bonferroni post hoc test was used to compare the PDGF concentrations between each testing condition.

Results

Under 75 degrees Celsius of heating, the resultant paste-like PRP end product had the highest concentration of PDGF in picograms per milliliter (pg/mL) as compared with other heating conditions (p < 0.05). The viscosity of the paste-like PRP was measured to be 70,000 centipoise (cP), which is similar to the viscosity of a toothpaste. The paste-like PRP end product was able to release PDGF continuously for about 14 days, with the highest concentration achieved on the 8^th day with an average of 35646 ± 2499 pg/mL. In nonthermally treated liquid-form PRP sample, the highest number of PRP was observed on the 4^th day with an average value of 8444 ± 831 pg/mL. Under the heating conditions of 55 and 95 degrees Celsius, the highest concentration of PDGF was observed on the 5^th day (13346 ± 764 pg/mL and 3440 ± 303 pg/mL, respectively). Under the heating conditions of 65 and 85 degrees Celsius, the highest concentration of PDGF was observed on the 7^th day (15468 ± 744 pg/mL and 20432 ± 1118 pg/mL, respectively).

Conclusion

Through thermal oscillation, liquid-form PRP can be converted to paste-like PRP end product with a viscosity similar to that of a toothpaste. The best heating condition was discovered to be 75 degrees Celsius. The paste-like PRP was able to release PDGF continuously for about 2 weeks, with the highest concentration obtained on the 8^th day. The findings in this study suggested that paste-like PRP may be a viable option in treating degenerative knee joint diseases.

A Review of the Clinical Effectiveness and Safety of Hybrid Cooperative Complexes in Intra-articular Viscosupplementation

Viscosupplementation by intra-articular (i.a.) injection of the non-sulfated glycosaminoglycan (GAG) hyaluronic acid (HA) is a conservative therapy widely accepted in clinical practice for the management of osteoarthritis (OA) and joint diseases. The aim of viscosupplementation is to restore the rheological properties of the synovial fluid to relieve joint inflammation and pain and improve joint function through a chondroprotective effect. However, there is a range of hyaluronic acid products for OA that differ in preparation, molecular weight, rheological characteristics and concentration, and different i.a. formulations are more suited to particular patient populations and clinical situations, in part because of anatomical differences between joints. This paper focuses on innovative hybrid cooperative complexes of high and low molecular weight hyaluronic acid (HA-HL) and hyaluronic acid plus sodium chondroitin (HA-SC) that have been developed. Both products are formulated with pharmaceutical-grade, highly purified hyaluronic acid obtained with a multi-step biofermentation process, with properties that make them suitable across a range of degenerative joint diseases. They represent progress in building on the symptomatic and functional benefits of viscosupplementation in joint disease, with the additional beneficial effect of treating the patient with a high concentration of GAGs by a low number of injections. Here, we review the clinical evidence for the efficacy of a hybrid cooperative compound of HA-HL in various degenerative joint diseases, which suggests a synergistic effect of the different molecular weight hyaluronans that together more closely mimic the physiological composition of synovial fluid. Similarly, the evidence shows that HA-SC is safe, effective, and well tolerated in hip OA, with rapid and clinically significant improvements in pain symptoms and functionality. Such innovations in viscosupplementation expand the usefulness of the modality in the management of OA and other joint diseases, complemented by a lack of systemic or local side effects that allow the concurrent use of other drugs if needed.

Does vehicle-based delivery of mesenchymal stromal cells give superior results in knee osteoarthritis? Meta-analysis of randomized controlled trials

STUDY DESIGN

Meta-analysis.

OBJECTIVES

We aim to analyze and compare the efficacy and safety of vehicle-based delivery of Mesenchymal Stromal Cells (MSCs) in the management of osteoarthritis of the knee from Randomized Controlled Trials (RCTs) available in the literature.

MATERIALS AND METHODS

We conducted independent and duplicate electronic database searches including PubMed, Embase, Web of Science, and Cochrane Library till August 2021 for RCTs analyzing the efficacy and safety of vehicle-based delivery of MSCs in the management of knee osteoarthritis. Visual Analog Score (VAS) for Pain, Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score, and adverse events were the outcomes analyzed. Analysis was performed in R-platform using OpenMeta [Analyst] software.

RESULTS

21 studies involving 936 patients were included for analysis. None of the studies made a direct comparison of the direct and vehicle-based delivery of MSCs, hence we pooled the results of all the included studies of both groups and made a comparative analysis of their outcomes. Although at 6 months, both direct and vehicle-based delivery of MSCs showed significantly better VAS improvement (p = 0.002, p = 0.010), it was not consistent at 1 year for the vehicle delivery (p = 0.973). During 6 months and 12 months, direct delivery of MSCs (p < 0.001, p < 0.001) outperformed vehicle delivery (p = 0.969, p = 0.922) compared to their control based on WOMAC scores respectively. Both direct (p = 0.713) and vehicle-based delivery (p = 0.123) of MSCs did not produce significant adverse events compared to their controls.

CONCLUSION

Our analysis of literature showed that current clinically employed methods of vehicle-based delivery of MSCs such as platelet-rich plasma, hyaluronic acid did not demonstrate superior results compared to direct delivery, concerning the efficacy of treatment measured by improvement in pain, functional outcomes, and safety. Hence, we urge future clinical trials to be conducted to validate the effectiveness of advanced delivery vehicles such as composite bioscaffolds to establish their practical utility in cartilage regeneration with respect to its encouraging in-vitro evidence.

Therapeutic Exercise and Conservative Injection Treatment for Early Knee Osteoarthritis in Athletes: A Scoping Review

Background and Objectives: Recent evidence highlighted a higher prevalence of knee osteoarthritis (kOA) among young and former ex-professional athletes. Although the practice of a highly demanding sport is considered a predisposing factor for the knee joint cartilage degeneration, articular cartilage seems to positively respond to a moderate load increase. We aim to investigate recent evidence on the conservative management of early kOA in athletes, with a particular emphasis on therapeutic exercise and injection treatment, in order to highlight whether there are any indications that can influence clinical and rehabilitation practice. Materials and Methods: A scoping review was conducted, screening MEDLINE and PEDro databases for studies published over the past twenty years on the topic. Studies in English, with accessible abstracts, were included in the review. The PICO framework was used (P—patient: athletes, I—Intervention: conservative treatment with therapeutic exercise or injection therapies, C—Comparison: not needed, O—Outcomes: clinical outcomes). Clinical trials, randomized controlled trials, and longitudinal studies were considered. Results: Four studies were finally included in the review. Therapeutic exercise seems to have beneficial effects on prevention of cartilage degeneration, on pain reduction, and on physical function enhancement. On the other hand, in mild to moderate stages of kOA the intra-articular viscosupplementation with Hyaluronic Acid showed a medium to long-term improvement in joint pain and function. The Platelet Rich Plasma treatment also showed a significant improvement in pain and function up to 12 months. Conclusions: Despite the heterogeneity of the studies considered, a multimodal treatment combining therapeutic exercise and moderate aerobic activity (such as running) should be indicated to prevent kOA development. In cases of symptomatic kOA it may be indicated to add minimally invasive injection therapy that seems to contribute to the improvement of motor function and symptomatology.

Applications of the regenerative capacity of platelets in modern medicine

Platelets produce platelet growth factors such as PDGF, IGF-1, EGF-, HGF, TGFβ, bFGF, and VEGF, which are crucial in regulating all stages of the wound healing process. The source of these substances is platelet-rich plasma (PRP). Over the past five decades, the interest and use of the regenerative properties of platelets have increased significantly in many different fields of medicine around the world. PRP and PRF plate preparations are used in: 1. Dentistry (they reduce bleeding, facilitate and accelerate soft tissue healing and bone regeneration - FGF 2, IGF-1, IGF-2, TGF-β1, and PDGF); 2. Sports medicine - IGF-1, IGF-2, TGF-β, VEGF, PDGF and bFGF, EGF); 3. dermatology and cosmetology (treatment of alopecia, hair reconstruction - FGF-7, HGF, acne scars, skin rejuvenation and regeneration, treatment of chronic and poorly healing wounds, burns, and acquired vitiligo); 4. Gynecology and reproductive medicine (treatment of infertility, erectile dysfunction - PDGF-β, TGF-β, IGF-1, in sexual dysfunction - PDGF, in vaginal atrophy); 5 Ophthalmology (in the healing of corneal epithelial wounds, in the treatment of dormant corneal ulcers, dry eye syndrome and the reconstruction of the corneal surface; 6. Neurology (regeneration of neurons, pain alleviation, and clinical symptoms - TGF-β 1, IGF-1, PDGF, VEGF) and FGF). Platelet-rich plasma therapy is a very interesting alternative and complement to traditional methods of treatment. However, the potential for using platelets is still not fully understood. The composition of platelet-rich plasma depends on many factors that may affect its use's efficacy and clinical benefits. Further research is necessary to standardize PRP delivery's preparation procedures and methods for a specific disease entity or clinical case.

Hyaluronan and Derivatives: An In Vitro Multilevel Assessment of Their Potential in Viscosupplementation

In this research work, viscosupplements based on linear, derivatized, crosslinked and complexed HA forms were extensively examined, providing data on the hydrodynamic parameters for the water-soluble-HA-fraction, rheology, sensitivity to enzymatic hydrolysis and capacity to modulate specific biomarkers’ expression in human pathological chondrocytes and synoviocytes. Soluble HA ranged from 0 to 32 mg/mL and from 150 to 1330 kDa MW. The rheological behavior spanned from purely elastic to viscoelastic, suggesting the diversity of the categories that are suitable for restoring specific/different features of the healthy synovial fluid. The rheological parameters were reduced in a diverse manner upon dilution and hyaluronidases action, indicating different durations of the viscosupplementation effect. Bioactivity was found for all the samples, increasing the expression of different matrix markers (e.g., hyaluronan-synthase); however, the hybrid cooperative complexes performed better in most of the experiments. Hybrid cooperative complexes improved COLII mRNA expression (~12-fold increase vs. CTR), proved the most effective at preserving cell phenotype. In addition, in these models, the HA samples reduced inflammation. IL-6 was down-regulated vs. CTR by linear and chemically modified HA, and especially by hybrid complexes. The results represent the first comprehensive panel of data directly comparing the diverse HA forms for intra-articular injections and provide valuable information for tailoring products’ clinical use as well as for designing new, highly performing HA-formulations that can address specific needs.

Optimization of Lyophilized Hyperacute Serum (HAS) as a Regenerative Therapeutic in Osteoarthritis

Hyperacute serum (HAS) is a blood derivative product that promotes the proliferation of various cell types and controls inflammation in vitro. The aim of this study is to investigate the regenerative potential of different formulations of HAS, including lyophilized and hyaluronic acid combined versions, to obtain a stable and standardized therapeutic in osteoarthritis (OA), which may be able to overcome the variability limitations of platelet-rich plasma (PRP). Primary human osteoarthritic chondrocytes were used for testing cellular viability and gene expression of OA-related genes. Moreover, a co-culture of human explants of cartilage, bone and synovium under inflammatory conditions was used for investigating the inflammatory control capacities of the different therapeutics. In this study, one formulation of lyophilized HAS achieved the high cell viability rates of liquid HAS and PRP. Gene expression analysis showed that HAS induced higher Col1a1 expression than PRP. Cytokine quantification from supernatant fluids revealed that HAS treatment of inflamed co-cultures significantly reduced levels of IL-5, IL-15, IL-2, TNFα, IL-7 and IL-12. To conclude, lyophilized HAS is a stable and standardized therapeutic with high potential in joint regeneration.

Platelet-Rich Plasma Combined With Hyaluronic Acid Improves Pain and Function Compared With Hyaluronic Acid Alone in Knee Osteoarthritis: A Systematic Review and Meta-analysis

PURPOSE

To evaluate the efficacy of platelet-rich plasma (PRP) combined with hyaluronic acid (HA) injections versus HA injections alone for the management of knee osteoarthritis (OA).

METHODS

This study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Eligible randomized-controlled trials and observational studies directly comparing combined PRP-HA injections with HA injections alone were identified through a search of PubMed, Scopus, and Cochrane Central databases from inception to May 2020. A random effects model meta-analysis was conducted and the I² statistic was used to assess for heterogeneity.

RESULTS

Four studies comprising 377 patients (PRP-HA: 193, HA: 184) with knee OA ranging from I-IV Kellgren-Lawrence grading scale were included. The final follow-up was 12 months in 3 studies and 6 months in 1 study. Patients who received PRP combined with HA had significantly greater improvements compared with those injected with HA alone in terms of visual analog scale scores at 3-month (standardized mean difference [SMD] 1.13; 95% confidence interval [CI] 0.56-1.70; I² = 56.7%; P < .001), 6-month (SMD 1.08; 95% CI 0.54-1.62; I² = 67.9%; P < .001), and 12-month (SMD 1.13; 95% CI 0.74-1.52; I² = 0.0%; P < .001) and 12-month Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical functioning (SMD 0.91; 95% CI 0.65-1.17; I² = 0.0%; P < .001) and 12-month WOMAC stiffness (SMD 1.09; 95% CI 0.80-1.38; I² = 0.0%; P < .001) scores. No difference was identified in terms of 12-month WOMAC pain score (SMD 0.36; 95% CI -0.19 to 0.91; I² = 74.1%; P = .195).

CONCLUSIONS

Symptomatic patients with knee OA who were injected with a combination of PRP and HA demonstrated greater improvement in pain and function compared with patients who received HA injections only, as assessed by 3-, 6-, and 12-month visual analog scale scores and 12-month WOMAC physical function and stiffness scores. This study provides encouraging evidence for the use of the combined PRP-HA injections in the management of symptomatic patients with knee OA.

LEVEL OF EVIDENCE

III (meta-analysis of randomized and non-randomized comparative trials).

A Hyaluronan and Platelet-Rich Plasma Hydrogel for Mesenchymal Stem Cell Delivery in the Intervertebral Disc: An Organ Culture Study

The purpose of the present pilot study was to evaluate the effect of a hydrogel composed of hyaluronic acid (HA) and platelet-rich plasma (PRP) as a carrier for human mesenchymal stem cells (hMSCs) for intervertebral disc (IVD) regeneration using a disc organ culture model. HA was mixed with batroxobin (BTX) and PRP to form a hydrogel encapsulating 1 × 10⁶ or 2 × 10⁶ hMSCs. Bovine IVDs were nucleotomized and filled with hMSCs suspended in ~200 μL of the PRP/HA/BTX hydrogel. IVDs collected at day 0 and nucleotomized IVDs with no hMSCs and/or hydrogel alone were used as controls. hMSCs encapsulated in the hydrogel were also cultured in well plates to evaluate the effect of the IVD environment on hMSCs. After 1 week, tissue structure, scaffold integration, hMSC viability and gene expression of matrix and nucleus pulposus (NP) cell markers were assessed. Histological analysis showed a better preservation of the viability of the IVD tissue adjacent to the gel in the presence of hMSCs (~70%) compared to the hydrogel without hMSCs. Furthermore, disc morphology was maintained, and the hydrogel showed signs of integration with the surrounding tissues. At the gene expression level, the hydrogel loaded with hMSCs preserved the normal metabolism of the tissue. The IVD environment promoted hMSC differentiation towards a NP cell phenotype by increasing cytokeratin-19 (KRT19) gene expression. This study demonstrated that the hydrogel composed of HA/PRP/BTX represents a valid carrier for hMSCs being able to maintain a good cell viability while stimulating cell activity and NP marker expression.

Comparing efficacy of intraarticular single crosslinked Hyaluronan (HYAJOINT Plus) and platelet-rich plasma (PRP) versus PRP alone for treating knee osteoarthritis

Intraarticular hyaluronan or platelet-rich plasma (PRP) is widely used in the treatment of knee osteoarthritis (OA). The efficacy of combined hyaluronan with PRP remained inconclusive. This study aimed to investigate the efficacy of combined a single crosslinked hyaluronan (HYAJOINT Plus) and a single PRP versus a single PRP in patients with knee OA. In a prospective randomized-controlled trial, 85 patients with knee OA (Kellgren-Lawrence 2) were randomized to receive a single intraarticular injection of HYAJOINT Plus (3 ml, 20 mg/ml) followed by 3 ml PRP (the combined-injection group, N = 43) or a single injection of 3 ml PRP (the one-injection group, N = 42). The primary outcome was the change from baseline in the visual analog scale (VAS) pain (0–00 mm) at 6 months. Secondary outcomes included The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC, Likert Scale), Lequesne index, single leg stance test (SLS), use of rescue analgesics and patient satisfaction at 1, 3 and 6 months. Seventy-eight patients were available for the intention-to-treat analysis at 6 months. Both groups improved significantly in VAS pain, WOMAC, Lequesne index and SLS at each follow-up visit (p < 0.001). Patients receiving a single PRP experienced significantly greater improvements in VAS pain than patients receiving combined injections at 1-month follow-up (adjusted mean difference: − 5.6; p = 0.017). There were no significant between-group differences in several of the second outcomes at each follow-up visit, except the WOMAC-pain and WOMAC-stiffness scores favoring the one-injection group at 1 month (p = 0.025 and p = 0.011). However, at 6-month follow-up, the combined-injection group achieved significantly better VAS pain reduction (p = 0.020). No serious adverse events occurred following injections. In conclusion, either combined injections of HYAJOINT Plus and PRP or a single PRP alone was safe and effective for 6 months in patients with Kellgren-Lawrence 2 knee OA. Combined injections of HYAJOINT Plus and PRP achieved better VAS pain reduction than a single PRP at 6 months. The results indicating a long term benefit effect of a combination of HYAJOINT Plus and PRP in a particular subset of patients with moderate knee OA need to be replicated in larger trials.

ClinicalTrials.gov number NCT04315103.

Combination of preconditioned adipose-derived mesenchymal stem cells and platelet-rich plasma improves the repair of osteoarthritis in rat

Aim: To observe the combined effect of platelet-rich plasma (PRP) and preconditioned adipose-derived mesenchymal stem cells (ADMSCs) on the injured articular cartilage of the rat. Materials & methods: Animals in the study received an intra-articular injection of PRP and preconditioned ADMSCs, both in combination and separately. The response to therapeutic intervention was evaluated by inflammatory markers, proteoglycans content, chondrogenesis and gene expression analyses. Results: The combined therapy resulted in a reduction of IL-6 and TNF-α, increased proteoglycan content of the articular cartilage, upregulation of Acan, Col2a1 and PCNA genes. Downregulation of Col1a1, Col10a1 and Casp3 genes was observed as compared with the untreated osteoarthritis rat model. Conclusion: PRP potentiates the effects of ADMSCs on the repair of damaged articular cartilage.

Rheological Properties and Growth Factors Content of Platelet-Rich Plasma: Relevance in Veterinary Biomedical Treatments

Platelet-rich plasma (PRP) is a nontransfusional hemocomponent, considered as a powerful concentrate of growth factors (GFs) therapeutically used to stimulate tissue regeneration. The use of autologous PRP, as the patient’s own biological material, for therapeutic purposes represents a safe and effective alternative to conventional treatments in both human and veterinary medicine. The aim of this study was the characterization of canine PRP from rheological and biological points of view. Thus, a characterization of the viscoelastic properties of the PRP systems was performed in order to clarify the influence of different calcium concentrations, in the presence of autologous thrombin-rich solution, on the PRP gels’ mechanical properties, from which the applicability of these systems in biomedical treatments is strongly dependent. Then, an evaluation of the content of GFs in PRP, activated or not with thrombin, and stored at different temperatures (37 °C and −20 °C) was performed over time, outlining, for the first time, the importance of the effect of physiological temperature (37 °C) on the production of GFs. A clinical case study conducted in a dog with a complete rupture of the common calcaneal tendon (Achilles tendon) confirmed the relevance of this hemocomponent in the daily veterinary clinical activity and the potential translational value for human health.

Bone marrow aspirate clot: A feasible orthobiologic

Musculoskeletal disorders are one of the major health burdens and a leading source of disability worldwide, affecting both juvenile and elderly populations either as a consequence of ageing or extrinsic factors such as physical injuries. This condition often involves a group of locomotor structures such as the bones, joints and muscles and may therefore cause significant economic and emotional impact. Some pharmacological and non-pharmacological treatments have been considered as potential solutions, however, these alternatives have provided quite limited efficacy due to the short-term effect on pain management and inability to restore damaged tissue. The emergence of novel therapeutic alternatives such as the application of orthobiologics, particularly bone marrow aspirate (BMA) clot, have bestowed medical experts with considerable optimism as evidenced by the significant results found in numerous studies addressed in this manuscript. Although other products have been proposed for the treatment of musculoskeletal injuries, the peculiar interest in BMA, fibrin clot and associated fibrinolytic mechanisms continues to expand. BMA is a rich source of various cellular and molecular components which have demonstrated positive effects on tissue regeneration in many in vitro and in vivo models of musculoskeletal injuries. In addition to being able to undergo self-renewal and differentiation, the hematopoietic and mesenchymal stem cells present in this orthobiologic elicit key immunomodulatory and paracrine roles in inflammatory responses in tissue injury and drive the coagulation cascade towards tissue repair via different mechanisms. Although promising, these complex regenerative mechanisms have not yet been fully elucidated.

Blindness associated with platelet-rich plasma temporomandibular joint injections

This case report highlights an ocular complication associated with platelet-rich plasma temporomandibular joint injections. This pioneering treatment can risk irreversible visual loss. This case highlights the importance of an experienced technique, in depth understanding of facial anatomy, and promptly recognising and referring the patient to a specialist to manage the complication should it arise.

Hyaluronic acid and platelet-rich plasma for the management of knee osteoarthritis

PURPOSE

Symptomatic knee osteoarthritis (OA) remains a substantial cause of pain and disability worldwide and effective management in young patients without indications for total knee arthroplasty remains challenging. Intra-articular injections represent a viable option in the non-operative treatment of knee OA. Hyaluronic acid (HA) and platelet-rich plasma (PRP) are two commonly utilized intra-articular treatment modalities that are of particular clinical interest in the current literature. The purpose of this manuscript is to provide a concise review of the current literature on the use of HA, PRP, and HA-PRP conjugates for the treatment of symptomatic knee OA.

METHODS

A review of the literature utilizing PubMed, OVID/Medline, and Cochrane databases on basic science and clinical literature pertaining to preparation, composition, and outcomes of HA, PRP, and HA-PRP conjugates in patients with symptomatic knee OA.

RESULTS

Both HA and PRP have been shown to be efficacious for the treatment of symptomatic knee OA, with HA injections providing limited short-term improvement, while PRP may provide greater therapeutic relief, particularly with the use of leukocyte-poor (LP-PRP) formulations. Despite limited data, the combination of different formulations of HA-PRP conjugates may provide a synergistic effect, resulting in a clinically significant improvement in both pain and function.

CONCLUSION

In patients with symptomatic knee OA, intra-articular HA and PRP provide short-term improvement in pain and function, while the efficacy of HA-PRP conjugates warrants further study.

Histopathologic Evaluation of the Effects of Intraurethral Platelet Rich Plasma in Urethral Trauma Experimentally Induced in Rat Model

OBJECTIVE

To determine the efficacy of platelet rich plasma applied early initialization after urethral trauma for preventing inflammation and spongiofibrosis.

MATERIALS AND METHODS

Twenty-three rats were randomized and divided into 3 groups, with 10 rats in 2 groups. Only sham group had 3 rats. The urethras of all rats were traumatized with a pediatric urethrotome knife at 6- and 12-o'clock. For 15 days, group I was given platelet rich plasma (PRP) once a day without urethral injury (sham group), group II (n = 10) was not given any medical treatment only urethral injury group (UI-PRP), group III (n = 10) was given PRP once a day intraurethrally as instillation using a 22 ga catheter sheath with urethral injury (UI+PRP). On day 15, the penises of the rats were degloved to perform penectomy.

RESULTS

A significant difference was detected in all parameters when the sham, UI-PRP, UI+PRP groups were compared (respectively, P = .001, / <.001, / .008 / .007) and a significant difference was observed among mucosal inflammation, fibrosis, and edema parameters when UI-PRP and UI+PRP groups were compared. (Respectively; P <.001, / <.001 / .006).

CONCLUSION

In this study, it was shown that intraurethral PRP applied after urethral trauma significantly decreased mucosal inflammation, spongiofibrosis, and edema. Depending on the results we acquired in this study, we think that PRP may be a promising option in urethral stricture treatment.

Gene Expression Profiles of Peripheral Blood Monocytes in Osteoarthritis and Analysis of Differentially Expressed Genes

Background

There is little understanding of the molecular processes involved in the pathogenesis of osteoarthritis, limiting early diagnosis and effective treatment of OA. Use of genechips can provide insights into the molecular pathogenesis of diseases. In this study, determination of gene expression profiles of osteoarthritis peripheral blood mononuclear cells will allow exploration of the molecular pathogenesis of OA and find out more candidate biomarkers and potential drug targets of OA.

Result

A total of 1231 DEGs were screened out including 791 upregulated DEGs and 440 downregulated DEGs. The most significant upregulated DEG was RPL38, which may inhibit chondrocyte differentiation and synthesis of the extracellular matrix. PIK3CA, PIK3CB, PIK3CD, PIK3R1, MAPK14, IL1A, JUND, FOSL2, and PPP3CA were the gene symbols of the osteoclast differentiation pathway which was the most significant pathway enriched by DEGs. However, the MAPK signaling pathway occupied the core position of all the pathways which can regulate apoptosis, cell cycle, wnt signaling pathway, p53 signaling pathway, and phosphatidylinositol signaling system. Furthermore, PI3Ks may regulate IL1A, JUND, FOSL2 and PPP3CA through the MAPK signaling pathway.

Conclusion

These identified DEGs and pathways may be novel biomarkers to monitor the changes of OA and can be a potential drug target for the treatment of OA.

Wound Healing: In Vitro and In Vivo Evaluation of a Bio-Functionalized Scaffold Based on Hyaluronic Acid and Platelet-Rich Plasma in Chronic Ulcers

Chronic ulcers are characterized by loss of substance without a normal tendency towards spontaneous healing. The Wound Bed Preparation Guideline advises that after diagnosis, the expert should correct the biological state of the ulcer micro-environment based on TIME principles (Tissue, Infection, Moisture balance, Epidermal). There are many ways to treat such ulcers, for example through use of advanced dressings, negative pressure, surgical toilets, dermal substitutes, autologous skin grafting, and free or local flaps. In vitro and in vivo pre-clinical models hold widely acknowledged potential yet complex limitations. Tissue bioengineering could be an ideal approach to foster innovative strategies in wound healing. Our observational study reports on an in vitro and in vivo evaluation of a bio-functionalized scaffold composed of platelet-rich plasma (PRP) and hyaluronic acid (HA) used in 182 patients affected by chronic ulcers (diabetic and vascular), comparing the results with a control group of 182 patients treated with traditional dressings (HA alone). After 30 days the patients who had undergone the combined treatment (PRP + HA), showed 96.8% ± 1.5% re-epithelialization, as compared to 78.4% ± 4.4% in the control group (HA only). Within 80 days, they had 98.4% ± 1.3% re-epithelialization as compared to 87.8% ± 4.1% in the control group (HA only; p < 0.05). No local recurrence was observed during the follow-up period. PRP + HA treatment showed stronger regenerative potential in terms of epidermal proliferation and dermal renewal compared with HA alone.

Tissue Engineering Strategies for Intervertebral Disc Treatment Using Functional Polymers

Intervertebral disc (IVD) is the fibrocartilage between the vertebrae, allowing the spine to move steadily by bearing multidirectional complex loads. Aging or injury usually causes degeneration of IVD, which is one of the main reasons for low back pain prevalent worldwide and reduced quality of life. While various treatment strategies for degenerative IVD have been studied using in vitro studies, animal experiments, and clinical trials, there are unsolved limitations for endogenous regeneration of degenerative IVD. In this respect, several tissue engineering strategies that are based on the cell and scaffolds have been extensively researched with positive outcomes for regeneration of IVD tissues. Scaffolds made of functional polymers and their diverse forms mimicking the macro- and micro-structure of native IVD enhance the biological and mechanical properties of the scaffolds for IVD regeneration. In this review, we discuss diverse morphological and functional polymers and tissue engineering strategies for endogenous regeneration of degenerative IVD. Tissue engineering strategies using functional polymers are promising therapeutics for fundamental and endogenous regeneration of degenerative IVD.

Novel Hybrid Gels Made of High and Low Molecular Weight Hyaluronic Acid Induce Proliferation and Reduce Inflammation in an Osteoarthritis In Vitro Model Based on Human Synoviocytes and Chondrocytes

High molecular weight hyaluronan (H-HA) has a pivotal role in the maintenance of normal functions of synovial fluid and structure of the articular joint, but it has been shown that its concentration is reduced in patients affected by degenerative cartilage diseases, such as osteoarthritis (OA). The aim of this study was to investigate the anti-inflammatory effects and properties of hybrid cooperative complexes based on high and low molecular weight hyaluronan (HCC) compared to H-HA on human primary cells derived by pathological joints. In addition, the rheological behavior of HCC was evaluated in order to define their potential as viscosupplement gel in degenerated joints. The experiments were performed using an in vitro model of OA based on human chondrocytes and synoviocytes isolated from degenerated joints of patients hospitalized for surgical replacement. In order to assess the anti-inflammatory effects of HCC, we evaluated NF-kB, COMP-2, IL-6, and IL-8 as specific markers at the transcriptional and/or protein level. Moreover, the proliferative properties of HCC were assessed using time lapse video microscopy. We showed that chondrocytes and synoviocytes clearly presented an altered cytokine profile compatible with a severe ongoing inflammation status. H-HA and, above all, HCC significantly reduced levels of the specific biomarkers evaluated and improved cartilage healing. The rheological profile indicated HCC suitability for intra-articular injection in joint diseases. HCC viscoelastic properties and the protective/anti-inflammatory effect on human chondrocytes and synoviocytes suggest the novel HCC-based gels as a valid support for OA management.

Active viscosupplements for osteoarthritis treatment

OBJECTIVE

Osteoarthritis is a chronic, painful and disabling disease which prevalence is increasing in developing countries. Patients with osteoarthritis present a reduced synovial fluid viscoelasticity due to a reduction in concentration and molecular weight of hyaluronic acid. Currently, the main treatment used to restore the compromised rheological properties of synovial fluid is the viscosupplementation by hyaluronic acid injections that can be combined with oral anti-inflammatory drugs for pain relief. Combination of viscosupplements with chemical agents or drugs is emerging as a new strategy to provide a double action of synovial fluid viscoelasticity recovery and the therapeutic effect of the bioactive principle.

METHODS

In this review, we present the latest research on the combination of viscosupplements with active molecules. We conducted a literature review of articles published in different web search engines and categorized according to the active molecule introduced into the viscosupplement.

RESULTS

Generally, the introduction of anti-inflammatory molecules have shown to improve pain relief although some cytotoxicity has been demonstrated especially for non-steroidal anti-inflammatory drugs. Other molecules such as antioxidant or disease modifying osteoarthritis drugs have been reported to improve viscosupplementation action. Drug delivery systems combined with hyaluronic acid could enhance the activity of the encapsulated molecules and provide better control over the drug release. Finally, biological approaches such as the use of stem cells or platelet-rich plasma seem to be the most promising strategies for cartilage recovery.

CONCLUSIONS

Combination therapy of viscosupplements with therapeutic agents, drug delivery systems or regenerative therapies can improve viscosupplementation outcome in terms of pain relief and joint functionality. However, further research is needed in order to reach more conclusive results.

Improvising PRP for use in osteoarthritis knee- upcoming trends and futuristic view

Platelet rich plasma (PRP) has clearly emerged offering a possible solution that could modify the disease process and offer symptomatic relief in early osteoarthritis of knee. Great efforts are underway to improve PRP products for use in knee osteoarthritis (OA). Upcoming research is focused on the ideal PRP type, dose, frequency of injection and mode of injection. The combination of PRP with biocompatible carriers/scaffolds like gelatin hydrogel and chitosan appear to be promising based on early in vitro and animal studies. PRP in combination with hyaluronate has also emerged to have synergistic and additive effects. This article intends to review the recent trends and advancing ideas for improvising PRP for use in early knee OA treatment.

Submucosal injection of platelet-rich plasma in endoscopic resection of large sessile lesions

AIM

To prospectively evaluate the efficacy of submucosal injection of platelet-rich plasma (PRP) on endoscopic resection of large sessile lesions.

METHODS

Eleven patients were submitted to endoscopic mucosal resection (EMR) with prior injection of PRP, obtained at the time of endoscopy. Patients were followed during 1 mo. The incidence of adverse events (delayed bleeding or perforation) and the percentage of mucosal healing (MHR) after 4 wk were registered.

RESULTS

EMR was performed in 11 lesions (46.4 mm ± 4 mm, range 40-70 mm). Delayed bleeding or perforation was not observed in any patient. Mean ulcerated area at baseline was 22.7 cm2 ± 11.7 cm2 whereas at week 4 were 2.9 cm2 ± 1.5 cm2. Patients treated with PRP showed a very high MHR after 4 wk (87.5%).

CONCLUSION

PRP is an easy-to-obtain solution with proven and favourable biological activities that could be used in advanced endoscopic resection.

Injectable Systems for Intra-Articular Delivery of Mesenchymal Stromal Cells for Cartilage Treatment: A Systematic Review of Preclinical and Clinical Evidence

Stem cell-based therapy is a promising approach to treat cartilage lesions and clinical benefits have been reported in a number of studies. However, the efficacy of cell injection procedures may be impaired by cell manipulation and damage as well as by cell dissemination to non-target tissues. To overcome such issues, mesenchymal stromal cell (MSC) delivery may be performed using injectable vehicles as containment systems that further provide a favorable cell microenvironment. The aim of this systematic review was to analyze the preclinical and clinical literature on platelet-rich plasma (PRP), hyaluronic acid (HA), and hydrogels for the delivery of MSCs. The systematic literature search was performed using the PubMed and Web of science databases with the following string: "(stem cells injection) AND (platelet rich plasma OR PRP OR platelet concentrate OR biomaterials OR hyaluronic acid OR hydrogels)": 40 studies (19 preclinical and 21 clinical) met the inclusion criteria. This review revealed an increasing interest on the use of injectable agents for MSC delivery. However, while negligible adverse events and promising clinical outcomes were generally reported, the prevalence of low quality studies hinders the possibility to demonstrate the real benefits of using such injectable systems. Specific studies must be designed to clearly demonstrate the added benefits of these systems to deliver MSCs for the treatment of cartilage lesions and osteoarthritis.

Injectable Systems for Intra-Articular Delivery of Mesenchymal Stromal Cells for Cartilage Treatment: A Systematic Review of Preclinical and Clinical Evidence

Stem cell-based therapy is a promising approach to treat cartilage lesions and clinical benefits have been reported in a number of studies. However, the efficacy of cell injection procedures may be impaired by cell manipulation and damage as well as by cell dissemination to non-target tissues. To overcome such issues, mesenchymal stromal cell (MSC) delivery may be performed using injectable vehicles as containment systems that further provide a favorable cell microenvironment. The aim of this systematic review was to analyze the preclinical and clinical literature on platelet-rich plasma (PRP), hyaluronic acid (HA), and hydrogels for the delivery of MSCs. The systematic literature search was performed using the PubMed and Web of science databases with the following string: "(stem cells injection) AND (platelet rich plasma OR PRP OR platelet concentrate OR biomaterials OR hyaluronic acid OR hydrogels)": 40 studies (19 preclinical and 21 clinical) met the inclusion criteria. This review revealed an increasing interest on the use of injectable agents for MSC delivery. However, while negligible adverse events and promising clinical outcomes were generally reported, the prevalence of low quality studies hinders the possibility to demonstrate the real benefits of using such injectable systems. Specific studies must be designed to clearly demonstrate the added benefits of these systems to deliver MSCs for the treatment of cartilage lesions and osteoarthritis.

Origin and Efficacy of Hyaluronan Injections in Knee Osteoarthritis: Randomized, Double-Blind Trial

BACKGROUND Several hyaluronan preparations are available that have different dosage forms, origins, and concentrations. The objective of the study was to compare the efficacy of intra-articular chemically cross-linked hyaluronan (CCH) and avian-derived hyaluronan (ADH) injections in knee osteoarthritis (KOA) patients. MATERIAL AND METHODS In total, 258 patients were randomized into 2 groups of 129 each: patients who received CCH injection (CCH group) and patients who received ADH injection (ADH group). Radiographic Kellgren-Lawrence score, visual analog scale (VAS) pain score, Lequesne index score, the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index, single-limb stance (SLS) test, and timed "Up-and-Go" (TUG) test were performed. The Mann-Whitney U test or independent t-test following Bonferroni adjustment was performed for statistical analysis at 95% of confidence level. RESULTS The CCH group had improved VAS pain score (P<0.0001, q=54.803), total WOMAC score (P<0.0001, q=4.753), Lequesne index score (P<0.0001, q=3.208), and SLS time (P<0.0001, q=8.76) at the end of 6 months as compared to those in the ADH group. After 6 months of follow-up, the ADH group had improved TUG time (P=0.0148, q=3.385) as compared to baseline. Both groups of patients had the similar improvement in Kellgren-Lawrence score and mild to moderate adverse effects after 6 months. CONCLUSIONS CCH injection was superior to ADH injection.

Platelet rich plasma for the management of hair loss: Better alone or in combination?

Platelet-rich plasma (PRP) and autologous protein-based treatments have recently emerged as a potential therapeutic approach for hair loss-related disorders including androgenetic alopecia and alopecia areata. The safety and efficacy of repeated intradermal injections of PRP has proved to promote hair growth in a number of randomized clinical trials. Biologically active proteins and cytokines released upon platelet activation have shown to induce folliculogenesis and activate the anagen growing phase of dormant bulbs. Interestingly, further studies have revealed that combining PRP with other hair loss-related products may enhance the final performance of the treatment. These synergistic approaches include Food and Drug Administration (FDA) approved drugs such as finasteride or minoxidil, bioactive macromolecules and cell-based therapies. Here, recent research involving alone or combined therapy with platelet-rich plasma for the management of hair loss-related disorders are outlined and future prospects are discussed.

Injections for Knee Osteoarthritis: Corticosteroids, Viscosupplementation, Platelet-Rich Plasma, and Autologous Stem Cells

This article reviews the benefits of corticosteroid, viscosupplementation, platelet-rich plasma, and autologous mesenchymal stem cell injections for the treatment of patients with knee osteoarthritis. Integrating injections into both clinical and surgical practices is complicated given existing health insurance reimbursement policies. This review describes the outcomes associated with these interventions and appropriate methods of navigating the existing reimbursement pathways to help providers implement these treatments into their practices.

A novel personalized 3D injectable protein scaffold for regenerative medicine

Biomaterials should be designed to closely resemble the characteristics and functions of the native extracellular matrix to provide mechanical support and signals to direct biological events. Here we have developed a novel injectable plasma rich in growth factors (PRGF-Endoret)-based formulation that combines a thermal-denaturation step of plasma with an autologous fibrin crosslinking. Rheological and mechanical properties were evaluated. Additionally, the microstructure and biological capacity of the biomaterial was also characterized. This novel formulation exhibited ideal mechanical properties and a gel-like behavior with the ability to progressively release its growth factor load over time. The results also suggested that the novel injectable formulation is non-cytotoxic, biocompatible and suitable for cell ingrowth as it is deduced from the fibroblast proliferation within the scaffold. Finally, stimulation of both cell proliferation and matrix proteins synthesis demonstrated the regenerative potential of this autologous protein based injectable scaffold.

Can hybrid hyaluronic acid represent a valid approach to treat rizoarthrosis? A retrospective comparative study

BACKGROUND

Osteoarthritis (OA) of the trapeziometacarpal joint (TMJ) is a disabling condition with a significant impact on quality of life. The optimal management of hand OA requires a combination of non-pharmacological and pharmacological treatments that include intra-articular (i.a.) therapy. EULAR experts recommend corticosteroid injections in TMJ OA and underline the usefulness of hyaluronic acid (HA). The aim of this study was the assessment of the efficacy and tolerability of i.a. injections of a hybrid formulation of HA (Sinovial H-L®) in comparison to triamcinolone in patients with TMJ OA.

METHODS

This 6-months observational comparative study, retrospective analyzed the medical records of 100 patients with monolateral or bilateral TMJ OA, treated with two injections of Sinovial H-L® (Sinovial H-L Group) or of triamcinolone acetonide (Triamcinolone Group). Clinical assessments were recorded at the time of the first and second injection and after one, 3 and 6 months. The primary outcomes were the change in global pain on a Visual Analogue Scale (VAS) and in hand function evaluated by the Functional Index for Hand OA (FIHOA) from baseline to month 6. Secondary outcomes were the improvement of the duration of morning stiffness, Health Assessment Questionnaire (HAQ) and the Medical Outcomes Study 36-Item Short Form (SF-36). The comparison between the two groups of treatment were performed with the Wilcoxon rank-sum test for continuous variables and with chi-square or Fisher exact test for categorical variables. Statistical significance was set at p < 0.05.

RESULTS

Both therapies provided effective pain relief and joint function improvement, but the benefits achieved were statistically significantly superior in the Sinovial H-L Group than the Triamcinolone Group after one month (p < 0.01) from the beginning of the therapy and during the 6-months follow-up (p < 0.001). Furthermore, Sinovial H-L® was associated with a significant decrease in the duration of morning stiffness and with a significant improvement in the HAQ score and physical component summary (PCS)-SF-36.

CONCLUSIONS

Our results suggested that the hybrid formulation of HA may be more effective than triamcinolone in pain relief and joint function improvement with a rapid and persistent effect, resulting a valid alternative to steroid in the management of TMJ OA.

TRIAL REGISTRATION

ClinicalTrials.gov, date of registration: June 14, 2017, NCT03200886 . The present trial was retrospectively registered.

Clinically relevant hydrogel-based on hyaluronic acid and platelet rich plasma as a carrier for mesenchymal stem cells: Rheological and biological characterization

Intervertebral disc regeneration is quickly moving towards clinical applications. However, it is still missing an ideal injectable hydrogel to support mesenchymal stem cells (MSC) delivery. Herein, a new injectable hydrogel composed of platelet rich plasma (PRP) and hyaluronic acid (HA) blended with batroxobin (BTX) as gelling agent, was designed to generate a clinically relevant cell carrier for disc regeneration. PRP/HA/BTX blend was tested for rheological properties. Amplitude sweep, frequency sweep, and rotational measurements were performed and viscoelastic properties were evaluated. Human MSC encapsulated in PRP/HA/BTX hydrogel were cultured in both growing medium and medium with or without TGF-β1 up to day 21. The amount of glycosaminoglycan was evaluated. Quantitative gene expression evaluation for collagen type II, aggrecan, and Sox 9 was also performed. Rheological tests showed that the hydrogel jellifies in 15 min 20°C and in 3 min at 37°C. Biological test showed that MSCs cultured in the hydrogel maintain high cell viability and proliferation. Human MSC within the hydrogel cultured with or without TGF-β1 showed significantly higher GAG production compared to control medium. Moreover, MSCs in the hydrogel underwent differentiation to chondrocyte-like cells with TGF-β1, as shown by histology and gene expression analysis. This novel hydrogel improves viability and proliferation of MSCs supporting the differentiation process toward chondrocyte-like cells. Rheology tests showed optimal gelation kinetics at room temperature for manipulation and faster gelation after transplantation (37°C). The clinical availability of all components of the hydrogel will allow a rapid translation of this regenerative approach into the clinical scenario. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2109-2116, 2017.

Hyaluronic acid increases tendon derived cell viability and proliferation in vitro: comparative study of two different hyaluronic acid preparations by molecular weight

Background

Hyaluronic Acid (HA) has been already approved by Food and Drug Administration (FDA) for osteoarthritis (OA), while its use in the treatment of tendinopathy is still debated. The aim of this study was to evaluate the effects of two different HA on human rotator cuff tendon derived cells in terms of cell viability, proliferation and apoptosis.

Methods

An in vitro model was developed on human tendon derived cells from rotator cuff tears to study the effects of two different HA preparations: Sinovial HL® (High-Low molecular weight) (MW: 80-100 kDa) and KDa Sinovial Forte SF (MW: 800-1200), at various concentrations. Tendon derived cells morphology was evaluated after 0, 7 and 14 d of culture. Viability and proliferation were analyzed after 0, 24, and 48 h of culture and apoptosis occurrence was assessed after 24 h of culture.

Results

All the HAPs tested here increased viability and proliferation, in a dose-dependent manner and they reduced apoptosis at early stages (24 h) compared to control cells (without HAPs).

Conclusions

HAPs enhanced viability and proliferation and counteracted apoptosis in tendon derived cells.

Intra-articular therapies for osteoarthritis

INTRODUCTION

Conventional medical therapies for osteoarthritis are mainly palliative in nature, aiming to control pain and symptoms. Traditional intra-articular therapies are not recommended in guidelines as first line therapy, but are potential alternatives, when conventional therapies have failed.

AREAS COVERED

Current and future intra-articular drug therapies for osteoarthritis are highlighted, including corticosteroids, hyaluronate, and more controversial treatments marketed commercially, namely platelet rich plasma and mesenchymal cell therapy. Intraarticular disease modifying osteoarthritis drugs are the future of osteoarthritis treatments, aiming at structural modification and altering the disease progression. Interleukin-1β inhibitor, bone morphogenic protein-7, fibroblast growth factor 18, bradykinin B2 receptor antagonist, human serum albumin, and gene therapy are discussed in this review. The evolution of drug development in osteoarthritis is limited by the ability to demonstrate effect. High quality trials are required to justify the use of existing intra-articular therapies and to advocate for newer, promising therapies.

EXPERT OPINION

Challenges in osteoarthritis therapy research are fundamentally related to the complexity of the pathological mechanisms of osteoarthritis. Novel drugs offer hope in a disease with limited medical therapy options. Whether these future intra-articular therapies will provide clinically meaningful benefits, remains unknown.