Stem cell application for osteoarthritis in the knee joint: A minireview

Stem cell therapy in sports medicine: current applications, challenges and future perspectives

Stem cells have demonstrated significant potential for tissue repair and regeneration, making them a promising therapeutic avenue in sports medicine. This review aims to provide a comprehensive overview of the current state of research on the application of stem cells in sports medicine. We will discuss the types of stem cells used, their mechanisms of action, and the clinical outcomes of stem cell therapy in different sports-related injuries. Furthermore, we will delve into the challenges and ethical considerations associated with stem cell therapy, as well as future directions and potential applications of stem cells in sports medicine.

Economic Evaluation of Glucosamine in Knee Osteoarthritis Treatments in Vietnam

Osteoarthritis (OA) is the degeneration of cartilage in joints that results in bones rubbing against each other; it causes uncomfortable symptoms such as pain, swelling, and stiffness and can lead to disability. It usually occurs in the elderly and causes a large medical burden. The aim of this study is to evaluate the cost-effectiveness between the standard treatment for osteoarthritis and standard treatment with added crystalline glucosamine sulfate at various stages. Markov analysis modeling was applied to evaluate the effect of both adding glucosamine compared to standard treatment from a societal perspective during whole patients' lifetimes. Data input was collected from reviews in previous studies. The outcome was measured in quality-adjusted life years (QALYs), and the Incremental Cost-Effectiveness Ratio (ICER) from a societal perspective was applied with 3% and discounted for all costs and outcomes. One-way analysis via the Tornado diagram was performed to investigate the change in factors in the model. In general, adding glucosamine into the standard treatment proved to be more cost-effective compared to the standard treatment. Particularly, the early-stage addition of glucosamine in the treatment was cost-effective compared to the post-stage addition of glucosamine. The addition of supplementing crystalline glucosamine sulfate to the whole regimen at any stage was cost-effective at the willingness-to-pay (WTP) threshold.

Strategies to capitalize on cell spheroid therapeutic potential for tissue repair and disease modeling

Cell therapies offer a tailorable, personalized treatment for use in tissue engineering to address defects arising from trauma, inefficient wound repair, or congenital malformation. However, most cell therapies have achieved limited success to date. Typically injected in solution as monodispersed cells, transplanted cells exhibit rapid cell death or insufficient retention at the site, thereby limiting their intended effects to only a few days. Spheroids, which are dense, three-dimensional (3D) aggregates of cells, enhance the beneficial effects of cell therapies by increasing and prolonging cell-cell and cell-matrix signaling. The use of spheroids is currently under investigation for many cell types. Among cells under evaluation, spheroids formed of mesenchymal stromal cells (MSCs) are particularly promising. MSC spheroids not only exhibit increased cell survival and retained differentiation, but they also secrete a potent secretome that promotes angiogenesis, reduces inflammation, and attracts endogenous host cells to promote tissue regeneration and repair. However, the clinical translation of spheroids has lagged behind promising preclinical outcomes due to hurdles in their formation, instruction, and use that have yet to be overcome. This review will describe the current state of preclinical spheroid research and highlight two key examples of spheroid use in clinically relevant disease modeling. It will highlight techniques used to instruct the phenotype and function of spheroids, describe current limitations to their use, and offer suggestions for the effective translation of cell spheroids for therapeutic treatments.

Effect of the combinative use of acupotomy therapy and ultrasonic drug penetration in treating knee joint osteoarthritis

BACKGROUND/INTRODUCTION

Knee joint osteoarthritis is a chronic disease that affects the health in aging population.

AIM

We explore a minimally invasive surgery combining the use of ultrasonic drug penetration to treat early stage of knee joint osteoarthritis.

DESIGN

In total, 75 patients were participated in acupotomy therapy and ultrasonic drug penetration to treat joint osteoarthritis.

METHODS

The WOMAC (the Western Ontario and McMaster Universities Osteoarthritis Index) scores were used to assess the performance.

RESULTS

There was a significant difference in the WOMAC score between the two groups of patients (P < 0.05). The total performance rate was about 86.4% and 50% in experiment and control groups.

CONCLUSION

The combination of acupotomy therapy and ultrasonic drug penetration has demonstrated to be effective and promising to treat knee joint osteoarthritis.

Small Ruminant Models for Articular Cartilage Regeneration by Scaffold-Based Tissue Engineering

Animal models play an important role in preclinical studies, especially in tissue engineering scaffolds for cartilage repair, which require large animal models to verify the safety and effectiveness for clinical use. The small ruminant models are most widely used in this field than other large animals because they are cost-effective, easy to raise, not to mention the fact that the aforementioned animal presents similar anatomical features to that of humans. This review discusses the experimental study of tissue engineering scaffolds for knee articular cartilage regeneration in small ruminant models. Firstly, the selection of these scaffold materials and the preparation process in vitro that have been already used in vivo are briefly reviewed. Moreover, the major factors influencing the rational design and the implementation as well as advantages and limitations of small ruminants are also demonstrated. As regards methodology, this paper applies principles and methods followed by most researchers in the process of experimental design and operation of this kind. By summarizing and comparing different therapeutic concepts, this paper offers suggestions aiming to increase the effectiveness of preclinical research using small ruminant models and improve the process of developing corresponding therapies.

Immunomodulatory Actions of Mesenchymal Stromal Cells (MSCs) in Osteoarthritis of the Knee

Cellular therapy offers regeneration which curbs osteoarthritis of the knee. Among cellular therapies, mesenchymal stromal cells (MSCs) are readily isolated from various sources as culture expanded and unexpanded cellular population which are used as therapeutic products. Though MSCs possess a unique immunological and regulatory profile through cross-talk between MSCs and immunoregulatory cells (T cells, NK cells, dendritic cells, B cells, neutrophils, monocytes, and macrophages), they provide an immunotolerant environment when transplanted to the site of action. Immunophenotypic profile allows MSCs to escape immune surveillance and promotes their hypoimmunogenic or immune-privileged status. MSCs do not elicit a proliferative response when co-cultured with allogeneic T cells in vitro. MSCs secrete a wide range of anti-inflammatory mediators such as PGE-2, IDO, IL-1Ra, and IL-10. They also stimulate the resilient chondrogenic progenitors and enhance the chondrocyte differentiation by secretion of BMPs and TGFβ1. We highlight the various mechanisms of MSCs during tissue healing signals, their interaction with the immune system, and the impact of their lifespan in the management of osteoarthritis of the knee. A better understanding of the immunobiology of MSC renders them as an efficient therapeutic product for the management of osteoarthritis of the knee.

Rare Fungal Infection in Arthritic Knee After Stem Cell Injection Managed by Novel Staged Primary Arthroplasty: A Case Report

CASE

A 72-year-old man with bilateral knee osteoarthritis treated elsewhere with bilateral intraarticular stem cell injections (SCIs) presented to us 2 months later with signs of infection in his left knee. Aspiration culture grew fungus Penicillium sp. First-stage total knee arthroplasty (TKA) included thorough joint debridement, lavage, standard bone cuts, and insertion of antibiotic-impregnated cement spacer. Second stage included spacer removal and final implantation. At the 1.5-year follow-up, he has a satisfactory clinical outcome without evidence of infection.

CONCLUSION

As far as we know, this is the first reported case of infective fungal arthritis secondary to intraarticular SCI successfully managed by a staged primary TKA.

Development of an Ex Vivo Murine Osteochondral Repair Model

OBJECTIVE

Mouse models are commonly used in research applications due to the relatively low cost, highly characterized strains, as well as the availability of many genetically modified phenotypes. In this study, we characterized an ex vivo murine osteochondral repair model using human infrapatellar fat pad (IPFP) progenitor cells.

DESIGN

Femurs from euthanized mice were removed and clamped in a custom multidirectional vise to create cylindrical osteochondral defects 0.5 mm in diameter and 0.5 mm deep in both condyles. The IPFP contains progenitors that are a promising cell source for the repair of osteochondral defects. For proof of concept, human IPFP-derived progenitor cells, from osteoarthritic (OA) patients, cultured as pellets, were implanted into the defects and cultured in serum-free medium with TGFβ3 for 3 weeks and then processed for histology and immunostaining.

RESULTS

The custom multidirectional vise enabled reproducible creation of osteochondral defects in murine femoral condyles. Implantation of IPFP-derived progenitor cells led to development of cartilaginous tissue with Safranin O staining and deposition of collagen type II in the extracellular matrix.

CONCLUSIONS

We showed feasibility in creating ex vivo osteochondral defects and demonstrated the regenerative potential of OA human IPFP-derived progenitors in mouse femurs. The murine model can be used to study the effects of aging and OA on tissue regeneration and to explore molecular mechanisms of cartilage repair using genetically modified mice.

Stem Cells for Treatment of Musculoskeletal Conditions - Orthopaedic/Sports Medicine Applications

A myriad of musculoskeletal conditions afflicts a vast number of the world's population from birth to death. Countless pathological diseases and traumatic injuries (acute and chronic) contribute to different human disabilities, causing a tremendous financial toll on the economy of healthcare. The medical field is continually searching for novel ways to combat orthopedically related conditions. The immediate goal is the restoration of anatomy then ultimately return of function in hopes of enhancing quality if not the quantity of life. Traditional methods involve surgical correction/reconstruction of skeletal deformities from fractures/soft tissue damage/ruptures or replacement/resection of degenerated joints. Modern research is currently concentrating on innovative procedures to replenish/restore the human body close to its original/natural state [1, 2].

Procedural Treatments for Knee Osteoarthritis: A Review of Current Injectable Therapies

Knee osteoarthritis is a common painful degenerative condition affecting the aging Canadian population. In addition to pain and disability, osteoarthritis is associated with depression, comorbid conditions such as diabetes, and increased caregiver burden. It is predicted to cost the Canadian healthcare system $7.6 billion dollars by 2031. Despite its high cost and prevalence, controversy persists in the medical community regarding optimal therapies to treat knee osteoarthritis. A variety of medications like nonsteroidal anti-inflammatories and opioids can cause severe side effects with limited benefits. Total knee arthroplasty, although a definitive management, comes with risk such as postoperative infections, revisions, and chronic pain. Newer injectable therapies are gaining attention as alternatives to medications because of a safer side effect profile and are much less invasive than a joint replacement. Platelet-rich plasma is beginning to replace the more common injectable therapies of intra-articular corticosteroids and hyaluronic acid, but larger trials are needed to confirm this effect. Small studies have examined prolotherapy and stem cell therapy and demonstrate some benefits. Trials involving genicular nerve block procedures have been successful. As treatments evolve, injectable therapies may offer a safe and effective pathway for patients suffering from knee osteoarthritis.

In vivo articular cartilage regeneration through infrapatellar adipose tissue derived stem cell in nanofiber polycaprolactone scaffold

In this study, we report the development of a nanofiber polycaprolactone scaffold that can act as a stem cell carrier to induce chondrogenesis and promote cartilage repair in vivo. Infrapatellar fat pads were obtained from sheep knee and the stem cells were isolated and characterized by flow cytometry. Defects were created in sheep knee, two defects received adipose tissue derived stem cells (ASCs)-polycaprolactone construct, second group received polycaprolactone (PCL), the third group was chosen as the ASCs group and the fourth group was control group. Morphological evaluation showed that defects treated with ASCs-scaffold constructs were completely filled with cartilage-like tissue, while other groups revealed the formation of a thin layer of cartilage-like tissue in the defects. Real-Time RT-PCR showed the increase in collagen type 2 mRNA levels, aggrecan and Sox9 in ASCs/PCL groups in comparison with the other groups. Immunofluorescence and toluidine blue staining results showed the protein expression of collagen type 2 and formation of round and polygonal clusters of chondrocytes in ASCS/PCL group. According to our results nanofiber polycaprolactone promoted the chondrogenesis of infrapatellar adipose tissue derived stem cells in vivo and could offer significant promise in the biological functionality of stem cell tissue engineering in clinical practice.

Nomenclature Inconsistency and Selective Outcome Reporting Hinder Understanding of Stem Cell Therapy for the Knee

BACKGROUND

The prospect of treating knee cartilage injury/pathology with mesenchymal stem cells (MSCs) has garnered considerable attention in recent years, but study heterogeneity and a lack of randomized controlled trials (RCTs) preclude quantitative analysis. The purpose of this review was to provide clinicians with an overview of RCTs that addresses 2 key areas that have been largely overlooked: nomenclature inconsistency and selective outcome reporting.

METHODS

RCTs that purported to use stem cells or MSCs to treat knee cartilage were identified with use of PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses). Study variables were compiled, and methodological quality was assessed. The cell treatments and the methods used to characterize them were recorded and compared. Clinical, radiographic, and arthroscopic outcomes were extracted and evaluated qualitatively.

RESULTS

There was extensive variation among the treatments, adjuvant therapies, and outcome measures. Treatments did not coincide with terminology. Significant differences in clinical outcomes were reported infrequently, and intra-group improvements or inter-group subscore differences were consistently highlighted, particularly when inter-group comparisons were left unreported.

CONCLUSIONS

Overall, there are isolated cases in which positive efficacy results have been published, but our results suggest that the generally positive efficacy conclusions concerning stem cell therapy for knee cartilage pathology may be overstated. Nevertheless, it is important to understand that the efficacy of stem cell therapies should not be considered in aggregate. Cells that are procured or processed differently produce entirely different drugs. When evaluating the efficacy of "stem cell" therapies, clinicians must consider the methodological quality, nomenclature, and inherent distinctness of each treatment.

A phase I-II controlled randomized trial using a promising novel cell-free formulation for articular cartilage regeneration as treatment of severe osteoarthritis of the knee

BACKGROUND

A promising novel cell-free bioactive formulation for articular cartilage regeneration, called BIOF2, has recently been tested in pre-clinical trials. The aim of the present study was to evaluate the efficacy and safety of BIOF2 for intra-articular application in patients with severe osteoarthritis of the knee.

METHODS

A prospective, randomized, 3-arm, parallel group clinical trial was conducted. It included 24 patients with severe osteoarthritis of the knee (WOMAC score 65.9 ± 17). Before they entered the study, all the patients were under osteoarthritis control through the standard treatment with nonsteroidal anti-inflammatory drugs (NSAIDs), prescribed by their family physician. Patients were distributed into three groups of 8 patients each (intra-articular BIOF2, total joint arthroplasty, or conservative treatment with NSAIDs alone). The WOMAC score, RAPID3 score, and Rasmussen clinical score were evaluated before treatment and at months 3, 6, and 12. BIOF2 was applied at months 0, 3, and 6. Complete blood count and blood chemistry parameters were determined in the BIOF2 group before treatment, at 72 h, and at months 1, 3, 6, and 12. In addition, articular cartilage volume was evaluated (according to MRI) at the beginning of the study and at month 12.

RESULTS

The NSAID group showed no improvement at follow-up. Arthroplasty and BIOF2 treatments showed significant improvement in all the scoring scales starting at month 3. There were no statistically significant differences between the BIOF2 group and the arthroplasty group at month 6 (WOMAC score: 19.3 ± 18 vs 4.3 ± 5; P = 0.24) or month 12 (WOMAC score: 15.6 ± 15 vs 15.7 ± 17; P = 1.0). Arthroplasty and BIOF2 were successful at month 12 (according to a WOMAC score: ≤ 16) in 75% of the patients and the daily use of NSAIDs was reduced, compared with the group treated exclusively with NSAIDs (RR = 0.33, 95% CI 0.12-0.87, P = 0.02. This result was the same for BIOF2 vs NSAIDs and arthroplasty vs NSAIDs). BIOF2 significantly increased the articular cartilage by 22% (26.1 ± 10 vs 31.9 ± 10 cm2, P < 0.001) and produced a significant reduction in serum lipids. BIOF2 was well tolerated, causing slight-to-moderate pain only upon application.

CONCLUSIONS

The intra-articular application of the new bioactive cell-free formulation (BIOF2) was well tolerated and showed no significative differences with arthroplasty for the treatment of severe osteoarthritis of the knee. BIOF2 can regenerate articular cartilage and is an easily implemented alternative therapy for the treatment of osteoarthritis. Trial registration Cuban Public Registry of Clinical Trials (RPCEC) Database RPCEC00000250. Registered 08/15/2017-Retrospectively registered, http://rpcec.sld.cu/en/trials/RPCEC00000250-En .

A promising novel formulation for articular cartilage regeneration: Preclinical evaluation of a treatment that produces SOX9 overexpression in human synovial fluid cells

Osteoarthritis (OA) is a chronic disorder of synovial joints, in which there is progressive softening and disintegration of the articular cartilage. OA is the most common form of arthritis, and is the primary cause of disability and impaired quality of life in the elderly. Despite considerable medical necessity, no treatment has yet been proven to act as a disease‑modifying agent that may halt or reverse the structural progression of OA. The replacement of the joint with a prosthesis appears to be the best option in the advanced stages of the disease. A formulation (BIOF2) for cartilage regeneration has been recently developed. The present study evaluated the effects of BIOF2 on gene expression in human cell cultures, followed by efficacy trials in three OA animal models. Human synovial fluid cells that were exposed to the formulation exhibited increased transcription factor SOX‑9 (SOX9; chondrogenic factor) expression, and decreased mimecan (mineralization inducer) and macrophage‑stimulating protein receptor (osteoclastogenic factor) expression. The intra‑articular application of BIOF2 in the animal models significantly increased cartilage thickness from 12 to 31% at 28 days, compared with articular cartilage treated with saline solution. The articular area and number of chondrocytes additionally increased significantly, maintaining an unaltered chondrocyte/mm2 proportion. Evaluation of the histological architecture additionally displayed a decrease in the grade of articular damage in the groups treated with BIOF2. In conclusion, BIOF2 has proven to be effective for treating OA in animal models, most likely due to SOX9 overexpression in articular cells.

Clinical efficacy and safety of mesenchymal stem cell transplantation for osteoarthritis treatment: A meta-analysis

Purpose

The aim of this study was to evaluate the therapeutic efficacy and safety of mesenchymal stem cells (MSCs) for the treatment of patients with knee osteoarthritis (OA).

Materials

We performed a meta-analysis of relevant published clinical studies. An electronic search was conducted for randomized controlled trials (RCTs) of MSC-based therapy in knee OA. The visual analogue scale (VAS), International Knee Documentation Committee (IKDC) form, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Lequesne algofunctional indices (Lequesne), Lysholm knee scale (Lysholm), Tegner activity scale (Tegner) and adverse events (AEs) were evaluated.

Results

Eleven eligible trials with 582 knee OA patients were included in the present meta-analysis. We demonstrated that MSC treatment could significantly decrease VAS and increase IKDC scoresafter a 24-month follow-up compared with controls (P<0.05). MSC therapy also showed significant decreases in WOMAC and Lequesne scores after the 12-month follow-up (P<0.01). Analysis of Lysholm (24-month) and Tegner (12- and 24-month) scores also demonstrated favorable results for MSC treatment (P<0.05).

Conclusion

Overall, MSC transplantation treatment was shown to be safe and has great potential as an efficacious clinical therapy for patients with knee OA.

A new treatment for knee osteoarthritis: Clinical evidence for the efficacy of Arthrokinex™ autologous conditioned serum

OBJECTIVE

The desired therapeutic effect of Arthrokinex™ autologous conditioned serum (ACS) is facilitated by the ability of IL-1-Ra to limit the destructive inflammatory intra-articular (IA) actions of IL-1β. Previous studies have proven the capacity of Arthrokinex™ (ACS) to induce the anti-inflammatory cytokine, IL-1-Ra. The primary purpose of this retrospective study was to investigate the effect of Arthrokinex™ (ACS) to reduce pain, improve joint function and enhance quality of life in patients with knee osteoarthritis.

METHODS

Venous blood from 100 patients with symptomatic knee osteoarthritis (KOA) was conditioned and injected into the affected joint in this treatment protocol. Each patient received a total of six ultrasound-guided IA injections at day 0, 7, 14, 90, 180, and 270 and followed for up to one year. Treatment outcome measures were assessed by three different patient-administered surveys at each visit. Using the Visual Analog Pain Scale (VAS), participants were asked to classify pain in the previous 24 h. The Extra Short Musculoskeletal Functional Assessment (XSMFA-D) survey is a series of 16 questions designed to determine the functionality of the OA-affected joint. Finally, the patient completed a patient global impression of change (PGIC) survey to assess their individual level of satisfaction with the treatment regimen.

RESULTS

Compared to baseline, a total of 84% of patients reported better pain control at 6 months with 91% reporting improvement at 12 months. A robust and statistically significant improvement in each XSMFA-D subscale was observed in KOA patients over 12 months. The overall reduction of pain and enhanced joint function was observed within 1 week and sustained 3, 6 and even 12 months after the initial injection. In addition to symptomatic control of OA, 92% of patients reported satisfaction with the treatment regimen 12 months after the initial injection.

CONCLUSION

Given the favorable safety profile, reduction in pain and enhanced quality of life experienced by patients enrolled in this joint health program, Arthrokinex™ (ACS) has the potential to offer an alternative, chondroprotective, natural, molecular approach to treating pain and functionality in patients with mild, moderate or severe knee osteoarthritis.

Photobiomodulation therapy in the modulation of inflammatory mediators and bradykinin receptors in an experimental model of acute osteoarthritis

The objective of this study was to evaluate the effects of photobiomodulation therapy (PBMT) on inflammatory indicators, i.e., inflammatory mediators (TNF-α and CINC-1), and pain characterized by hyperalgesia and B1 and B2 receptor activation at 6, 24, and 48 h after papain-induced osteoarthritis (OA) in rats. Fifty-four rats were subjected to hyperalgesia evaluations and then divided randomly into three groups-a control group and two groups OA and OA PBMT group by using laser parameters at wavelength (808 nm), output power (50 mW), energy per point (4 Joules), power density (1.78 W/cm²), laser beam (0.028 cm²), and energy density (144 J/cm²)-the induction of osteoarthritis was then performed with 20-μl injections of a 4 % papain solution dissolved in 10 μl of saline solution, to which 10 μl of cysteine solution (0.03 M). The statistical analysis was performed using two-way ANOVA with Bonferroni's post hoc test for comparisons between the 6, 24, and 48 h and team points within each group, and between the control, injury, and PBMT groups, and p < 0.05 was considered to indicate a significant difference. The hyperalgesia was evaluated at 6, 24, and 48 h after the injury. PBMT at a wavelength of 808 nm and doses of 4 J, administered afterward, promotes increase at the threshold of pressure stimulus at 6, 24, and 48 h after application and promote cytokine attenuation levels (TNF and CINC-1) and bradykinin receptor (B1 and B2) along the experimental period. We conclude that photobiomodulation therapy was able to promote the reduction of proinflammatory cytokines such as TNF-α and CINC-1, to reduce the gene and protein expression of the bradykinin receptor (B1 and B2), as well as increasing the stimulus response threshold of pressure in an experimental model of acute osteoarthritis.

Kartogenin treatment prevented joint degeneration in a rodent model of osteoarthritis: A pilot study

Osteoarthritis (OA) is a major degenerative joint disease characterized by progressive loss of articular cartilage, synovitis, subchondral bone changes, and osteophyte formation. Currently there is no treatment for OA except temporary pain relief and end-stage joint replacement surgery. We performed a pilot study to determine the effect of kartogenin (KGN, a small molecule) on both cartilage and subchondral bone in a rat model of OA using multimodal imaging techniques. OA was induced in rats (OA and KGN treatment group) by anterior cruciate ligament transection (ACLT) surgery in the right knee joint. Sham surgery was performed on the right knee joint of control group rats. KGN group rats received weekly intra-articular injection of 125 μM KGN 1 week after surgery until week 12. All rats underwent in vivo magnetic resonance imaging (MRI) at 3, 6, and 12 weeks after surgery. Quantitative MR relaxation measures (T_1ρ and T₂ ) were determined to evaluate changes in articular cartilage. Cartilage and bone turnover markers (COMP and CTX-I) were determined at baseline, 3, 6, and 12 weeks. Animals were sacrificed at week 12 and the knee joints were removed for micro-computed tomography (micro-CT) and histology. KGN treatment significantly lowered the T_1ρ and T₂ relaxation times indicating decreased cartilage degradation. KGN treatment significantly decreased COMP and CTX-I levels indicating decreased cartilage and bone turnover rate. KGN treatment also prevented subchondral bone changes in the ACLT rat model of OA. Thus, kartogenin is a potential drug to prevent joint deterioration in post-traumatic OA. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1780-1789, 2016.

Secreted trophic factors of mesenchymal stem cells support neurovascular and musculoskeletal therapies

Adult mesenchymal stem cells (MSCs) represent a subject of intense experimental and biomedical interest. Recently, trophic activities of MSCs have become the topic of a number of revealing studies that span both basic and clinical fields. In this review, we focus on recent investigations that have elucidated trophic mechanisms and shed light on MSC clinical efficacy relevant to musculoskeletal applications. Innate differences due to MSC sourcing may play a role in the clinical utility of isolated MSCs. Pain management, osteochondral, nerve, or blood vessel support by MSCs derived from both autologous and allogeneic sources have been examined. Recent mechanistic insights into the trophic activities of these cells point to ultimate regulation by nitric oxide, nuclear factor-kB, and indoleamine, among other signaling pathways. Classic growth factors and cytokines-such as VEGF, CNTF, GDNF, TGF-β, interleukins (IL-1β, IL-6, and IL-8), and C-C ligands (CCL-2, CCL-5, and CCL-23)-serve as paracrine control molecules secreted or packaged into extracellular vesicles, or exosomes, by MSCs. Recent studies have also implicated signaling by microRNAs contained in MSC-derived exosomes. The response of target cells is further regulated by their microenvironment, involving the extracellular matrix, which may be modified by MSC-produced matrix metalloproteinases (MMPs) and tissue inhibitor of MMPs. Trophic activities of MSCs, either resident or introduced exogenously, are thus intricately controlled, and may be further fine-tuned via implant material modifications. MSCs are actively being investigated for the repair and regeneration of both osteochondral and other musculoskeletal tissues, such as tendon/ligament and meniscus. Future rational and effective MSC-based musculoskeletal therapies will benefit from better mechanistic understanding of MSC trophic activities, for example using analytical "-omics" profiling approaches.

Non-operative management of osteoarthritis of the knee joint

Osteoarthritis is a chronic disorder of synovial joints in which there is progressive softening and disintegration of articular cartilage accompanied by the growth of osteophytes. Treatment designed for osteoarthritis should aim at reducing pain, improve joint mobility, and limit functional impairment. It can be achieved by pharmacological and non-pharmacological means. Non-operative treatment of OA is useful for patients with KL grade 1-3, which are early stages of OA. However, in an advanced stage of OA (KL grade 4), surgical treatment is needed as definitive treatment.

MicroRNA-30a promotes extracellular matrix degradation in articular cartilage via downregulation of Sox9

OBJECTIVES

Sox9 has recently been reported to be a key mediator during cartilage degradation in osteoarthritis (OA). Our aim was to clarify the role of microRNA-30a (miR-30a) and its target gene Sox9 in regulation of extracellular matrix (ECM) degradation in OA.

MATERIALS AND METHODS

Expression of miR-30a in cartilage tissues and in primary chondrocytes from healthy and OA donors, was determined by real-time PCR, and levels of Sox9 mRNA and protein were analyzed by real-time PCR and western blotting, respectively. Subsequently, the target of miR-30a was predicted by bioinformatics and confirmed using a luciferase assay. Expression of ECM-related genes was determined by tissue-specific staining, immunofluorescence, real-time PCR, and western blotting. The role of miR-30a in OA was examined in vivo using a collagenase-induced OA rat model.

RESULTS

miR-30a was significantly upregulated and Sox9 was downregulated in primary chondrocytes from cartilage taken from OA donors compared to healthy controls. We showed that miR-30a specifically bound to the 3' UTR of Sox9, and overexpression of miR-30a downregulated expression levels of Sox9, proteoglycan aggrecan, and Col II compared to those induced by small interfering RNA transfection to knockdown Sox9. miR-30a inhibition reversed the effects of ECM degradation in vitro and in vivo.

CONCLUSIONS

miR-30a acts as a virulence MRA in OA, promoting ECM degradation by targeting Sox9 and by modulating activity of its downstream effectors Col II and proteoglycan aggrecan.

Human Mesenchymal Stem Cells Genetically Engineered to Overexpress Brain-derived Neurotrophic Factor Improve Outcomes in Huntington's Disease Mouse Models

Huntington's disease (HD) is a fatal degenerative autosomal dominant neuropsychiatric disease that causes neuronal death and is characterized by progressive striatal and then widespread brain atrophy. Brain-derived neurotrophic factor (BDNF) is a lead candidate for the treatment of HD, as it has been shown to prevent cell death and to stimulate the growth and migration of new neurons in the brain in transgenic mouse models. BDNF levels are reduced in HD postmortem human brain. Previous studies have shown efficacy of mesenchymal stem/stromal cells (MSC)/BDNF using murine MSCs, and the present study used human MSCs to advance the therapeutic potential of the MSC/BDNF platform for clinical application. Double-blinded studies were performed to examine the effects of intrastriatally transplanted human MSC/BDNF on disease progression in two strains of immune-suppressed HD transgenic mice: YAC128 and R6/2. MSC/BDNF treatment decreased striatal atrophy in YAC128 mice. MSC/BDNF treatment also significantly reduced anxiety as measured in the open-field assay. Both MSC and MSC/BDNF treatments induced a significant increase in neurogenesis-like activity in R6/2 mice. MSC/BDNF treatment also increased the mean lifespan of the R6/2 mice. Our genetically modified MSC/BDNF cells set a precedent for stem cell-based neurotherapeutics and could potentially be modified for other neurodegenerative disorders such as amyotrophic lateral sclerosis, Alzheimer's disease, and some forms of Parkinson's disease. These cells provide a platform delivery system for future studies involving corrective gene-editing strategies.

Comparative Matched-Pair Analysis of the Injection Versus Implantation of Mesenchymal Stem Cells for Knee Osteoarthritis

BACKGROUND

The mesenchymal stem cell (MSC)-based tissue engineering approach has been developed to address the problem of articular cartilage repair in knee osteoarthritis (OA). However, the most effective method of MSC application has not yet been established.

PURPOSE

To compare the injection and implantation of MSCs in patients with knee OA in terms of clinical and second-look arthroscopic outcomes.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Among 182 patients treated with arthroscopic surgery using MSCs for knee OA from October 2010 to August 2012, patients treated with an injection of MSCs in combination with platelet-rich plasma (injection group; n = 20) were pair-matched with patients who underwent MSC implantation on a fibrin glue scaffold (implantation group; n = 20) based on sex, age, and lesion size. Clinical outcomes were evaluated using the International Knee Documentation Committee (IKDC) score and Tegner activity scale, and cartilage repair was assessed arthroscopically with the International Cartilage Repair Society (ICRS) grading system.

RESULTS

The mean (±SD) IKDC and Tegner activity scores significantly improved from 38.5 ± 9.2 to 55.2 ± 15.0 and from 2.5 ± 1.2 to 3.5 ± 1.2, respectively, in the injection group and from 36.6 ± 4.9 to 62.7 ± 14.1 and from 2.3 ± 0.9 to 3.6 ± 1.1, respectively, in the implantation group at the time of second-look arthroscopic surgery (mean, 12.6 months postoperatively) (P < .001 in all cases). At final follow-up (mean, 28.6 months postoperatively), the mean IKDC and Tegner activity scores in the implantation group had improved further to 64.8 ± 13.4 and 3.9 ± 1.0, respectively (P < .001 and P = .035, respectively), while no significant improvements were found in the injection group (P = .130 and P = .655, respectively). At final follow-up, there was a significant difference in the mean IKDC score between groups (P = .049). Significant correlations between the number of administered MSCs and the postoperative clinical outcomes were found only in the injection group. Significant correlations between the clinical outcomes and the ICRS grades were found in both groups. The ICRS grades were significantly better in the implantation group (P = .041). In the injection group, 2 of the 20 lesions (10%) were grade I (normal), 5 (25%) were grade II (near normal), 8 (40%) were grade III (abnormal), and 5 (25%) were grade IV (severely abnormal). In the implantation group, 6 of the 20 lesions (30%) were grade I, 7 (35%) were grade II, 4 (20%) were grade III, and 3 (15%) were grade IV.

CONCLUSION

Utilizing the described method, MSC implantation for knee OA resulted in better clinical and second-look arthroscopic outcomes than an MSC injection.

Therapeutic Potential of Differentiated Mesenchymal Stem Cells for Treatment of Osteoarthritis

Osteoarthritis (OA) is a chronic, progressive, and irreversible degenerative joint disease. Conventional OA treatments often result in complications such as pain and limited activity. However, transplantation of mesenchymal stem cells (MSCs) has several beneficial effects such as paracrine effects, anti-inflammatory activity, and immunomodulatory capacity. In addition, MSCs can be differentiated into several cell types, including chondrocytes, osteocytes, endothelia, and adipocytes. Thus, transplantation of MSCs is a suggested therapeutic tool for treatment of OA. However, transplanted naïve MSCs can cause problems such as heterogeneous populations including differentiated MSCs and undifferentiated cells. To overcome this problem, new strategies for inducing differentiation of MSCs are needed. One possibility is the application of microRNA (miRNA) and small molecules, which regulate multiple molecular pathways and cellular processes such as differentiation. Here, we provide insight into possible strategies for cartilage regeneration by transplantation of differentiated MSCs to treat OA patients.

Electroacupuncture inhibits chronification of the acute pain of knee osteoarthritis: study protocol for a randomized controlled trial

Background

Previous studies have shown that electroacupuncture (EA) has a significant effect on acute pain, but it has not solved the clinical problem of the chronification of acute pain. Diffuse noxious inhibitory controls (DNIC) function as a reliable indicator to predict the risk of chronic pain events. DNIC function in knee osteoarthritis (KOA) patients has been demonstrated to gradually decrease during the development of chronic pain. The purpose of this study is to conduct a randomized, controlled clinical trial to determine if EA can repair impaired DNIC function and thus prevent chronification of the acute pain of KOA.

Methods/Design

This is a multicenter, single blind, randomized, controlled, three-arm, large-scale clinical trial. A total of 450 KOA patients will be randomly assigned to three groups. The strong EA group will receive EA with high-intensity current (2 mA < current < 5 mA) at the ipsilateral ‘Neixiyan’ (EX-LE5), ‘Dubi’(ST35), ‘Liangqiu’(ST34) and ‘Xuehai’ (SP10). The weak EA group will receive EA with low-intensity current (0 mA < current < 0.5 mA) on the same acupoints. The sham EA group will receive EA with low-intensity current (0 mA < current < 0.5 mA) with fine needles inserted superficially into the sites 2 cm lateral to the above acupoints. The patients will be treated with EA once a day, 30 minutes per session, in 5 sessions per week, for 2 weeks. In order to determine the best stage of KOA for effective EA intervention, patients within the treatment groups also will be divided into four stages. The primary outcomes are Visual Analog Scale (VAS), DNIC function and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Clinical assessments will be evaluated at baseline (before treatment) and after 5 to 10 sessions of treatment.

Discussion

This trial will be helpful in identifying whether strong EA is more effective than weak EA in reversing chronification of acute pain through repairing the impaired DNIC function and in screening for the best stage of KOA for effective EA intervention.

Trial registration

Chinese Clinical Trial Registry Number: ChiCTR-ICR-14005411. The date of registration is 31 October 2014.