Articular cartilage regeneration with autologous peripheral blood stem cells versus hyaluronic acid: a randomized controlled trial

Chondral regeneration in femoroacetabular lesions is favoured using peripheral blood stem cells with hyaluronan-based scaffold and micro-drilling: A prospective cohort study

Purpose

To determine whether intra-articular injections of peripheral blood stem cells (PBSC) with hyaluronan (HA)-based scaffold improve articular cartilage regeneration in chondral injuries caused by mixed-femoroacetabular impingement syndrome (FAIS) over a period longer than 24 months post-hip arthroscopy.

Methods

In this prospective cohort study, patients with mixed-FAIS and chondral injury ≥ IIIB according to the International Cartilage Regeneration and Joint Preservation Society grade or III/IV of Konan/Haddad classification underwent intra-articular injection of PBSC with an HA-based scaffold and micro-drillings during hip arthroscopy. The degree of chondral repair was measured at baseline and 5 years using the International Cartilage Repair Society morphologic score system (MSS) as the primary outcome. Pain was measured at baseline and 5 years using the Visual Analogue Scale for Pain (VAS Pain), and hip functionality was measured at baseline (presurgery), 6 months, 1 year, and 5 years using the Hip Outcome Score (HOS). The largest diameter of injury, median follow-up, side effects, complications, and improvements were described. T-test, ANOVA with multiple comparisons, and statistical power were estimated.

Results

From initially 34 cases, 25 patients were enrolled. The median follow-up was 5.1 ± 0.3 years. One patient (4%) reported a few side effects with filgrastim administration. No infection, tumours, or synovitis was reported. The largest diameters in zones two, three, and four were 12.4 ± 3.1 mm (n = 8), 13.5 ± 2.8 mm (n = 14), and 11.4 ± 1.9 mm (n = 3), respectively. Ninety-two percent (23/25) of patients improved their outcomes. The MSS and HOS increased from 3.8 ± 1.1 to 9.6 ± 1.5 pts (p < 0.001) and from 65.5 ± 13.0 to 93.9 ± 2.4 pts (p < 0.001), respectively. The VAS-Pain decreased from 5.3 ± 0.7 to 1.3 ± 0.6 mm (p < 0.001). The obtained a posteriori power-size was 0.99.

Conclusion

The intervention suggests a favourable impact on articular cartilage regeneration and clinical outcomes for hip chondral lesions in mixed-FAIS injuries after a median follow-up of 5.1 ± 0.3 years.

Level of Evidence

Level IV.

Does progress in microfracture techniques necessarily translate into clinical effectiveness?

BACKGROUND

Multitudinous advancements have been made to the traditional microfracture (MFx) technique, which have involved delivery of various acellular 2nd generation MFx and cellular MFx-III components to the area of cartilage defect. The relative benefits and pitfalls of these diverse modifications of MFx technique are still not widely understood.

AIM

To comparatively analyze the functional, radiological, and histological outcomes, and complications of various generations of MFx available for the treatment of cartilage defects.

METHODS

A systematic review was performed using PubMed, EMBASE, Web of Science, Cochrane, and Scopus. Patients of any age and sex with cartilage defects undergoing any form of MFx were considered for analysis. We included only randomized controlled trials (RCTs) reporting functional, radiological, histological outcomes or complications of various generations of MFx for the management of cartilage defects. Network meta-analysis (NMA) was conducted in Stata and Cochrane's Confidence in NMA approach was utilized for appraisal of evidence.

RESULTS

Forty-four RCTs were included in the analysis with patients of mean age of 39.40 (± 9.46) years. Upon comparing the results of the other generations with MFX-I as a constant comparator, we noted a trend towards better pain control and functional outcome (KOOS, IKDC, and Cincinnati scores) at the end of 1-, 2-, and 5-year time points with MFx-III, although the differences were not statistically significant (P > 0.05). We also noted statistically significant Magnetic resonance observation of cartilage repair tissue score in the higher generations of microfracture (weighted mean difference: 17.44, 95% confidence interval: 0.72, 34.16, P = 0.025; without significant heterogeneity) at 1 year. However, the difference was not maintained at 2 years. There was a trend towards better defect filling on MRI with the second and third generation MFx, although the difference was not statistically significant (P > 0.05).

CONCLUSION

The higher generations of traditional MFx technique utilizing acellular and cellular components to augment its potential in the management of cartilage defects has shown only marginal improvement in the clinical and radiological outcomes.

Osteochondral Regeneration in the Knee Joint with Autologous Peripheral Blood Stem Cells plus Hyaluronic Acid after Arthroscopic Subchondral Drilling: Report of Five Cases

BACKGROUND

Treatment of osteochondral defects (OCDs) of the knee joint remains challenging. The purpose of this study was to evaluate the clinical and radiological results of osteochondral regeneration following intra-articular injections of autologous peripheral blood stem cells (PBSC) plus hyaluronic acid (HA) after arthroscopic subchondral drilling into OCDs of the knee joint.

CASE PRESENTATION

Five patients with OCDs of the knee joint are presented. The etiology includes osteochondritis dissecans, traumatic knee injuries, previously failed cartilage repair procedures involving microfractures and OATS (osteochondral allograft transfer systems). PBSC were harvested 1 week after surgery. Patients received intra-articular injections at week 1, 2, 3, 4, and 5 after surgery. Then at 6 months after surgery, intra-articular injections were administered at a weekly interval for 3 consecutive weeks. These 3 weekly injections were repeated at 12, 18 and 24 months after surgery. Each patient received a total of 17 injections. Subjective International Knee Documentation Committee (IKDC) scores and MRI scans were obtained preoperatively and postoperatively at serial visits. At follow-ups of >5 years, the mean preoperative and postoperative IKDC scores were 47.2 and 80.7 respectively (p = 0.005). IKDC scores for all patients exceeded the minimal clinically important difference values of 8.3, indicating clinical significance. Serial MRI scans charted the repair and regeneration of the OCDs with evidence of bone growth filling-in the base of the defects, followed by reformation of the subchondral bone plate and regeneration of the overlying articular cartilage.

CONCLUSION

These case studies showed that this treatment is able to repair and regenerate both the osseous and articular cartilage components of knee OCDs.

Protecting the regenerative environment: selecting the optimal delivery vehicle for cartilage repair-a narrative review

Focal cartilage defects are common in youth and older adults, cause significant morbidity and constitute a major risk factor for developing osteoarthritis (OA). OA is the most common musculoskeletal (MSK) disease worldwide, resulting in pain, stiffness, loss of function, and is currently irreversible. Research into the optimal regenerative approach and methods in the setting of either focal cartilage defects and/or OA holds to the ideal of resolving both diseases. The two fundamentals required for cartilage regenerative treatment are 1) the biological element contributing to the regeneration (e.g., direct application of stem cells, or of an exogenous secretome), and 2) the vehicle by which the biological element is suspended and delivered. The vehicle provides support to the regenerative process by providing a protective environment, a structure that allows cell adherence and migration, and a source of growth and regenerative factors that can activate and sustain regeneration. Models of cartilage diseases include osteochondral defect (OCD) (which usually involve one focal lesion), or OA (which involves a more diffuse articular cartilage loss). Given the differing nature of these models, the optimal regenerative strategy to treat different cartilage diseases may not be universal. This could potentially impact the translatability of a successful approach in one condition to that of the other. An analogy would be the repair of a pothole (OCD) versus repaving the entire road (OA). In this narrative review, we explore the existing literature evaluating cartilage regeneration approaches for OCD and OA in animal then in human studies and the vehicles used for each of these two conditions. We then highlight strengths and challenges faced by the different approaches presented and discuss what might constitute the optimal cartilage regenerative delivery vehicle for clinical cartilage regeneration.

Preclinical Animal Study and Pilot Clinical Trial of Using Enriched Peripheral Blood-Derived Mononuclear Cells for Intervertebral Disc Degeneration

Low back pain (LBP) is a leading cause of long-term disability globally. Intervertebral disk degeneration (IVDD) is mainly responsible for discogenic pain in LBP-affected young patients. There is no effective therapy to reverse disease severity and IVDD progression. This study investigates the effect of human peripheral blood-derived mononuclear cells (PBMCs) on pain relief and life quality improvement in IVDD patients. The enriched monocytes of the PBMCs could differentiate into CD14 and CD206 double-positive M2 macrophages in vitro. Preclinical evidence in rats showed that the transplanted PBMCs exhibited anti-inflammatory and moderate tissue-repair effects on controlling IVDD progress in the rat model. The PBMCs significantly steered the aggrecan and type II collagen expressions and attenuated the pro-inflammatory cytokines in the affected disk. Based on the animal results, 36 patients with chronic low back pain (CLBP) were included in clinical trials. The control group was conservative care only, and the experimental group was platelet-rich plasma (PRP) and PBMCs intradiscal injections. We first confirmed the single lumbar disk causing the discogenic pain by provocative discography or magnetic resonance imaging (MRI). Discogenic LBP participants received one intradiscal injection of autologous PBMCs and followed for 6 months. Our clinical trial showed that patients' LBP and disability were significantly ameliorated after the PBMCs transplantation rather than PRP. These preclinical and pilot clinical studies indicate that intradiscal injection of the enriched PBMCs might be a feasible and potential cell therapy to control pain and disability in IVDD patients.

Cartilage Tissue Engineering in Practice: Preclinical Trials, Clinical Applications, and Prospects

Articular cartilage defects significantly compromise the quality of life in the global population. Although many strategies are needed to repair articular cartilage, including microfracture, autologous osteochondral transplantation, and osteochondral allograft, the therapeutic effects remain suboptimal. In recent years, with the development of cartilage tissue engineering, scientists have continuously improved the formulations of therapeutic cells, biomaterial-based scaffolds, and biological factors, which have opened new avenues for better therapeutics of cartilage lesions. This review focuses on advances in cartilage tissue engineering, particularly in preclinical trials and clinical applications, prospects, and challenges.

Infiltration therapy in the context of cartilage surgery

Guideline-based surgical cartilage therapy for focal cartilage damage offers highly effective possibilities to sustainably reduce patients' complaints and to prevent or at least delay the development of early osteoarthritis. In the knee joint, it has the potential to reduce almost a quarter of the arthroses requiring joint replacement caused by cartilage damage. Biologically effective injection therapies could further improve these results. Based on the currently available literature and preclinical studies, intra- and postoperative injectables may have a positive effect of platelet-rich plasma/fibrin (PRP/PRF) and hyaluronic acid (HA) on cartilage regeneration and, in the case of HA injections, also on the clinical outcome can be assumed. The role of a combination therapy with use of intra-articular corticosteroids is lacking in the absence of adequate study data and cannot be defined yet. With regard to adipose tissue-based cell therapy, the current scientific data do not yet justify any recommendation for its use. Further studies also regarding application intervals, timing and differences in different joints are required.

Repair of joint damage in patients with rheumatoid arthritis does not relate to previous suppression of inflammation: a subanalysis after 8 years treat-to-target in the BeSt-trial

OBJECTIVES

To investigate whether repair of erosions and joint space narrowing (JSN) in rheumatoid arthritis (RA) occurs and whether clinical variables predict this.

METHODS

Eight-year follow-up data of the BeSt-study were used. Patients with recent onset RA (1987 criteria) were randomised to four treatment strategies and treated-to-target (Disease Activity Score (DAS)≤2.4). Yearly radiographs of hands and feet were scored in non-chronological order by four independent readers, using the Sharp/van der Heijde score (SHS). Damage repair was defined as a negative ΔSHS in an individual joint, seen by ≥3 out of 4 readers and persisting ≥2 consecutive years. Associations between repair and DAS, prednisone use, infliximab use, anticitrullinated protein antibody, gender, age, body mass index, symptom duration and randomisation arm were investigated with logistic regression analyses, corrected for mean SHS.

RESULTS

Repair was seen in 17 patients (5.3%); 10 had regression of JSN, 7 of erosions, none had both. There were no significant associations in any of the regression analyses.

CONCLUSION

After 8 years of treatment to target DAS≤2.4 in 508 patients with recent onset RA, repair of JSN and erosions was seen in 17/320 patients (5.3%). Probably due to the rarity of repair, we found no associations with suppression of disease activity or other predictors and repair.

Enriched Peripheral Blood-Derived Mononuclear Cells for Treating Knee Osteoarthritis

Osteoarthritis (OA) is a common chronic skeletal disease in the elderly. There is no effective therapy to reverse disease severity and knee OA (KOA) progression, particularly at the late stage. This study aims to examine the effect of peripheral blood-derived mononuclear cells (PBMNCs) on pain and motor function rescue in patients with Kellgren-Lawrence (KL) grade II to IV KOA. Participants received one intra-articular (IA) injection of autologous PBMNCs. The mononuclear cells were isolated from peripheral blood, enriched by a specialized medium (MoFi medium), and separated by Ficoll-Paque solution. The isolated and enriched PBMNCs could differentiate into M1 and M2 macrophages in vitro. The in vivo anti-inflammatory effect of the PBMNCs was similar to that of bone marrow mesenchymal stem cells, evaluated by complete Freund's adjuvant-induced arthritis in rodents. A single-arm and open-label pilot study showed that patients' knee pain and motor dysfunction were significantly attenuated after the cell transplantation, assessed by visual analogue scale (VAS) and Knee injury and Osteoarthritis Outcome Score (KOOS) at 6 and 12 months post-treatment. Notably, the therapeutic effect of the PBMNCs treatment can be stably maintained for 24 months, as revealed by the KOOS scores. These preclinical and pilot clinical data suggest that IA injection of MoFi-PBMNCs might serve as a novel medical technology to control the pain and the progress of KOA.

Peripheral Blood-Derived Stem Cells for the Treatment of Cartilage Injuries: A Systematic Review

Background: The treatment of cartilage damage is a hot topic at present, and cell therapy is an emerging alternative therapy. Stem cells derived from peripheral blood have become the focus of current research due to the ease of obtaining materials and a wide range of sources.

Methods: We used a text search strategy using the [“mesenchymal stem cells” (MeSH term) OR “MSC” OR “BMMSC” OR “PBMSC” OR” PBMNC” OR “peripheral blood stem cells”] AND (cartilage injury [MeSH term] OR “cartilage” OR “chondral lesion”). After searching the literature, through the inclusion and exclusion criteria, the last included articles were systematically reviewed.

Result: We found that peripheral blood-derived stem cells have chondrogenic differentiation ability and can induce chondrogenic differentiation and repair in vivo and have statistical significance in clinical and imaging prognosis. It is an improvement of academic differences. Compared with the bone marrow, peripheral blood is easier to obtain, widely sourced, and simple to obtain. In the future, peripheral blood will be a more potential cell source for cell therapy in the treatment of cartilage damage.

Conclusion: Stem cells derived from peripheral blood can repair cartilage and are an important resource for the treatment of cartilage damage in the future. The specific mechanism and way of repairing cartilage need further study.

Hamizul MHA, Khairul Bariah AAN, Wan Kamarul Zaman WS, Nordin F. Regenerative Medicine Therapy in Malaysia: An Update

Regenerative medicine is a field in medicine that relates to the ability to correct congenital anomalies and to repair or replace tissues and organs that have been destroyed by age, disease, or trauma. To date, promising preclinical and clinical data supported the possibility of using regenerative medicine to treat both chronic diseases and acute insults, as well as maladies affecting a wide range of organ systems and contexts, such as dermal wounds, cardiovascular diseases and traumas, cancer treatments, and more. One of the regenerative medicine therapies that have been used widely is stem cells. Stem cells, especially mesenchymal and hematopoietic stem cells, play an important role in treating chronic diseases, such as leukemia, bone marrow, autoimmune disease, and urinary problems. Despite considerable advancements in stem cell biology, their applications are limited by ethical concerns about embryonic stem cells, tumor development, and rejection. Nevertheless, many of these constraints, are being overcome, which could lead to significant advancements in disease management. This review discusses the current developments and advancements of regenerative medicine therapy (RMT) advancements in Malaysia compared to other Asian countries. The limitations in the application of RMT are also highlighted.

Concentrated Bone Marrow Aspirate Is More Cellular and Proliferative When Harvested From the Posterior Superior Iliac Spine Than the Proximal Humerus

PURPOSE

The purpose of this study is to determine whether concentrated bone marrow aspirate (cBMA) from the posterior superior iliac spine (PSIS) or proximal humerus (PH) produces a more productive cellular harvest in patients undergoing arthroscopic rotator cuff repair.

METHODS

Patients under 80 years old undergoing surgery for arthroscopic rotator cuff repair were enrolled. Two 60 mL aliquots of BMA were harvested from each subject, one from the PSIS and one from the PH. Each aliquot was processed independently to create cBMA. Cellular composition was determined using an automated hemocytometer and proliferative potential was studied with colony forming unit (CFU) assays.

RESULTS

Twelve patients were recruited (7 male, 5 female). The average age was 64.3 years (range 46.1-77.25 years) with body mass index of 26.8 (range 20.0-34.3). The average total nucleated cells (TNC) from PH was 18.7 × 10⁶ cells/mL (95% confidence interval [CI], 4.4-33.0; standard deviation [SD], 24.8) with 3.9 CFU/mL (95% CI, 0.3-7.5, SD, 5.7). The average TNC count from the PSIS was 55.9 × 10⁶ cells/mL (95% CI, 25.3-86.4; SD, 52.9) with 32.5 CFU/mL (95% CI, 11.5-53.5; SD, 33.1). The PSIS had a 3.0 times greater total nucleated cell yield (P = .014) and 8.3 times greater number of CFU/mL (P = .024) when compared to the PH. The average harvest time from the PSIS was 5.6 minutes and from the PH was 11.0 minutes (P = .043); harvest time did not account for additional time to prep and drape the PSIS.

CONCLUSIONS

The cBMA harvested from the PSIS resulted in a 3.0 times greater cellular yield and an 8.3 times greater proliferative product than cBMA from the PH.

CLINICAL RELEVANCE

When a more cellular cBMA product is sought to augment rotator cuff tear repair surgery, the PSIS is the preferred site for harvest.

Methodological quality and risk of bias of systematic reviews and meta-analyses on stem cells for knee osteoarthritis: A cross-sectional survey

Clinical guidelines need high-quality studies to support clinical decision-making, in which the evidence often was collected from systematic reviews (SRs) and/or meta-analyses (MAs). At present, the methodological quality and risk of bias (RoB) of SRs/MAs on stem cell therapy for the treatment of knee osteoarthritis (KOA) has been poorly investigated. This study aims to strictly evaluate the methodological quality and RoB in SRs/MAs of stem cell therapy for KOA. Four electronic databases (PubMed, Embase, Cochrane Library, and Web of Science databases) were searched, from inception to October 5th, 2021. SRs/MAs involving randomized control trials (RCTs) or cohort studies on stem cell therapy for the treatment of KOA were included. The methodological quality and RoB were assessed using AMSTAR 2 and ROBIS tool respectively. In total, 22 SRs/MAs were included. According to the results obtained by AMSTAR 2 tool, all SRs/MAs were rated as "Critically low". Main methodological weaknesses were as follows: up to 81.82% did not meet protocol registration requirements, only 13.64% provided a list of excluded studies and justification, and 13.64% investigated and discussed the publication bias.. ROBIS-based RoB assessment showed that all the SRs/MAs were rated as "High". Besides, the lack of following the implementation of the PRISMA reporting guideline seems to reduce the methodological quality of the studies. The overall methodological quality of the SRs/MAs concerning the application of stem cell therapy in treating KOA is "Critically low", while the RoB is high. It is difficult to provide effective evidence for the formulation of guidelines for KOA treatment. We suggest that the relevant methodological quality assessment should be carried out in the future before the SRs/MAs are used as clinical evidence. In addition, it may be necessary for many journals to include the checklist with a submitted manuscript.

Methodological Flaws in Meta-Analyses of Clinical Studies on the Management of Knee Osteoarthritis with Stem Cells: A Systematic Review

(1) Background: Conclusions of meta-analyses of clinical studies may substantially influence opinions of prospective patients and stakeholders in healthcare. Nineteen meta-analyses of clinical studies on the management of primary knee osteoarthritis (pkOA) with stem cells, published between January 2020 and July 2021, came to inconsistent conclusions regarding the efficacy of this treatment modality. It is possible that a separate meta-analysis based on an independent, systematic assessment of clinical studies on the management of pkOA with stem cells may reach a different conclusion. (2) Methods: PubMed, Web of Science, and the Cochrane Library were systematically searched for clinical studies and meta-analyses of clinical studies on the management of pkOA with stem cells. All clinical studies and meta-analyses identified were evaluated in detail, as were all sub-analyses included in the meta-analyses. (3) Results: The inconsistent conclusions regarding the efficacy of treating pkOA with stem cells in the 19 assessed meta-analyses were most probably based on substantial differences in literature search strategies among different authors, misconceptions about meta-analyses themselves, and misconceptions about the comparability of different types of stem cells with regard to their safety and regenerative potential. An independent, systematic review of the literature yielded a total of 183 studies, of which 33 were randomized clinical trials, including a total of 6860 patients with pkOA. However, it was not possible to perform a scientifically sound meta-analysis. (4) Conclusions: Clinicians should interpret the results of the 19 assessed meta-analyses of clinical studies on the management of pkOA with stem cells with caution and should be cautious of the conclusions drawn therein. Clinicians and researchers should strive to participate in FDA and/or EMA reviewed and approved clinical trials to provide clinically and statistically valid efficacy.

Preclinical studies and clinical trials on mesenchymal stem cell therapy for knee osteoarthritis: A systematic review on models and cell doses

AIM

To provide a systematic analysis of the study design in knee osteoarthritis (OA) preclinical studies, focusing on the characteristics of animal models and cell doses, and to compare these to the characteristics of clinical trials using mesenchymal stem cells (MSCs) for the treatment of knee OA.

METHOD

A systematic and comprehensive search was conducted using the PubMed, Web of Science, Ovid, and Embase electronic databases for research papers published in 2009-2020 on testing MSC treatment in OA animal models. The PubMed database and ClinicalTrials.gov website were used to search for published studies reporting clinical trials of MSC therapy for knee OA.

RESULTS

In total, 9234 articles and two additional records were retrieved, of which 120 studies comprising preclinical and clinical studies were included for analysis. Among the preclinical studies, rats were the most commonly used species for modeling knee OA, and anterior cruciate ligament transection was the most commonly used method for inducing OA. There was a correlation between the cell dose and body weight of the animal. In clinical trials, there was large variation in the dose of MSCs used to treat knee OA, ranging from 1 × 10⁶ to 200 × 10⁶ cells with an average of 37.91 × 10⁶ cells.

CONCLUSION

Mesenchymal stem cells have shown great potential in improving pain relief and tissue protection in both preclinical and clinical studies of knee OA. Further high-quality preclinical and clinical studies are needed to explore the dose effectiveness relationship of MSC therapy and to translate the findings from preclinical studies to humans.

Implication of Mesenchymal Stem Cells and Their Derivates for Osteochondral Regeneration

Healing of articular cartilage defects presents a challenging issue, due to its regenerative shortcomings. Lacking vascularity and innervation of cartilage and low proliferative potential of chondrocytes are the main reasons for the limited healing potential of articular cartilage. Traditional reparative approaches are limited in their efficiency, hence there is a demand for novel reparative treatments. Mesenchymal stromal cells, preferred for clinical uses, can be readily derived from various sources and have been proven to have a therapeutic effect on cartilage and subchondral bone. Therefore, mesenchymal stromal cells, their derivates, and scaffolds have been utilized in research targeting osteochondral regeneration. The present review aims to comprehensively outline and discuss literature considering this topic published within last 5 years.

The Role of Mesenchymal Stromal Cells in the Management of Knee Chondral Defects

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Mesenchymal stromal cells (MSCs) are a subset of progenitor cells that help to promote tissue healing and regeneration through the secretion of various cytokines and growth factors. Although technically pluripotent, MSCs in vivo rarely repair damaged tissue through direct differentiation and engraftment.

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Augmentation of traditional marrow stimulation techniques with MSCs has been theorized to improve repair tissue quality and defect fill. Clinical trials evaluating this technique are limited but have shown modest improvements compared with isolated marrow stimulation.

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Various scaffolds also have been utilized in combination with MSCs to treat focal chondral defects. Although the techniques described are heterogeneous, many have shown promising early clinical outcomes.

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Newer techniques involving 3-dimensional bioprinted scaffolds seeded with MSCs allow for the recreation of complex architecture, more closely resembling articular cartilage. These techniques are evolving and have not yet been studied in human clinical trials.

Why and how to use the body's own stem cells for regeneration in musculoskeletal disorders: a primer

Background

Recently, the management of musculoskeletal disorders with the patients' own stem cells, isolated from the walls of small blood vessels, which can be found in great numbers in the adipose tissue, has received considerable attention. On the other hand, there are still misconceptions about these adipose-derived regenerative cells (ADRCs) that contain vascular-associated pluripotent stem cells (vaPS cells) in regenerative medicine.

Methods

Based on our previous publications on this topic, we have developed a concept to describe the significance of the ADRCs/vaPS cells in the field of orthobiologics as briefly as possible and at the same time as precisely as possible.

Results

The ADRCs/vaPS cells belong to the group of orthobiologics that are based on autologous cells. Because the latter can both stimulate a patient’s body's localized self-healing power and provide new cells that can integrate into the host tissue during the healing response when the localized self-healing power is exhausted, this group of orthobiologics appears more advantageous than cell-free orthobiologics and orthobiologics that are based on allogeneic cells. Within the group of orthobiologics that are based on autologous cells, enzymatically isolated, uncultured ADRCs/vaPS cells have several advantages over non-enzymatically isolated cells/microfragmented fat as well as over uncultured bone marrow aspirate concentrate and cultured cells (adipose-derived stem cells, bone marrow-derived mesenchymal stem cells).

Conclusions

The use of ADRCs/vaPS cells can be seamlessly integrated into modern orthopedic treatment concepts, which can be understood as the optimization of a process which—albeit less efficiently—also takes place physiologically. Accordingly, this new safe and effective type of treatment is attractive in terms of holistic thinking and personalized medicine.

Method Categorization of Stem Cell Therapy for Degenerative Osteoarthritis of the Knee: A Review

Current clinical applications of mesenchymal stem cell therapy for osteoarthritis lack consistency because there are no established criteria for clinical processes. We aimed to systematically organize stem cell treatment methods by reviewing the literature. The treatment methods used in 27 clinical trials were examined and reviewed. The clinical processes were separated into seven categories: cell donor, cell source, cell preparation, delivery methods, lesion preparation, concomitant procedures, and evaluation. Stem cell donors were sub-classified as autologous and allogeneic, and stem cell sources included bone marrow, adipose tissue, peripheral blood, synovium, placenta, and umbilical cord. Mesenchymal stem cells can be prepared by the expansion or isolation process and attached directly to cartilage defects using matrices or injected into joints under arthroscopic observation. The lesion preparation category can be divided into three subcategories: chondroplasty, microfracture, and subchondral drilling. The concomitant procedure category describes adjuvant surgery, such as high tibial osteotomy. Classification codes were assigned for each subcategory to provide a useful and convenient method for organizing documents associated with stem cell treatment. This classification system will help researchers choose more unified treatment methods, which will facilitate the efficient comparison and verification of future clinical outcomes of stem cell therapy for osteoarthritis.

Mesenchymal Stem Cells in the Treatment of Cartilage Defects of the Knee: A Systematic Review of the Clinical Outcomes

BACKGROUND

Osteochondral lesions are a common clinical problem and their management has been historically challenging. Mesenchymal stem cells have the potential to differentiate into chondrocytes and thus restore hyaline cartilage to the defect, theoretically improving clincal outcomes in these patients. They can also be harvested with minimal donor site morbidity.

PURPOSE

To assess the clinical and functional outcomes of mesenchymal stem cell implantation to treat isolated osteochondral defects of the knee. A secondary purpose is to assess the quality of the current available evidence as well as the radiological and histological outcomes. We also reviewed the cellular preparation and operative techniques for implantation.

STUDY DESIGN

Systematic review.

METHODS

A comprehensive literature search of 4 databases was carried out: CINAHL, Embase, MEDLINE, and PubMed. We searched for clinical studies reporting the outcomes on a minimum of 5 patients with at least 12 months of follow-up. Clinical, radiological, and histological outcomes were recorded. We also recorded demographics, stem cell source, culture technique, and operative technique. Methodological quality of each study was assessed using the modified Coleman methodology score, and risk of bias for the randomized controlled studies was assessed using the Cochrane Collaboration tool.

RESULTS

Seventeen studies were found, encompassing 367 patients. The mean patient age was 35.1 years. Bone marrow was the most common source of stem cells utilized. Mesenchymal stem cell therapy consistently demonstrated good short- to medium-term outcomes in the studies reviewed with no serious adverse events being recorded. There was significant heterogeneity in cell harvesting and preparation as well as in the reporting of outcomes.

CONCLUSION

Mesenchymal stem cells demonstrated a clinically relevant improvement in outcomes in patients with osteochondral defects of the knee. More research is needed to establish an optimal treatment protocol, long-term outcomes, and superiority over other therapies.

REGISTRATION

CRD42020179391 (PROSPERO).

Mobilized Peripheral Blood Stem Cells are Pluripotent and Can Be Safely Harvested and Stored for Cartilage Repair

PURPOSE

The primary objective of this study was to reproduce and validate the harvest, processing and storage of peripheral blood stem cells for a subsequent cartilage repair trial, evaluating safety, reliability, and potential to produce viable, sterile stem cells.

METHODS

Ten healthy subjects (aged 19-44 years) received 3 consecutive daily doses of filgrastim followed by an apheresis harvest of mononuclear cells on a fourth day. In a clean room, the apheresis product was prepared for cryopreservation and processed into 4 mL aliquots. Sterility and qualification testing were performed pre-processing and post-processing at multiple time points out to 2 years. Eight samples were shipped internationally to validate cell transport potential. One sample from all participants was cultured to test proliferative potential with colony forming unit (CFU) assay. Five samples, from 5 participants were tested for differentiation potential, including chondrogenic, adipogenic, osteogenic, endoderm, and ectoderm assays.

RESULTS

Fresh aliquots contained an average of 532.9 ± 166. × 10⁶ total viable cells/4 mL vial and 2.1 ± 1.0 × 10⁶ CD34+ cells/4 mL vial. After processing for cryopreservation, the average cell count decreased to 331.3 ± 79. × 10⁶ total viable cells /4 mL vial and 1.5 ± 0.7 × 10⁶ CD34+ cells/4 mL vial CD34+ cells. Preprocessing viability averaged 99% and postprocessing 88%. Viability remained constant after cryopreservation at all subsequent time points. All sterility testing was negative. All samples showed proliferative potential, with average CFU count 301.4 ± 63.9. All samples were pluripotent.

CONCLUSIONS

Peripheral blood stem cells are pluripotent and can be safely harvested/stored with filgrastim, apheresis, clean-room processing, and cryopreservation. These cells can be stored for 2 years and shipped without loss of viability.

CLINICAL RELEVANCE

This method represents an accessible stem cell therapy in development to augment cartilage repair.

Cell Sources for Cartilage Repair-Biological and Clinical Perspective

Cell-based therapy represents a promising treatment strategy for cartilage defects. Alone or in combination with scaffolds/biological signals, these strategies open many new avenues for cartilage tissue engineering. However, the choice of the optimal cell source is not that straightforward. Currently, various types of differentiated cells (articular and nasal chondrocytes) and stem cells (mesenchymal stem cells, induced pluripotent stem cells) are being researched to objectively assess their merits and disadvantages with respect to the ability to repair damaged articular cartilage. In this paper, we focus on the different cell types used in cartilage treatment, first from a biological scientist’s perspective and then from a clinician’s standpoint. We compare and analyze the advantages and disadvantages of these cell types and offer a potential outlook for future research and clinical application.

Safety and Efficacy of Kartigen® in Treating Cartilage Defects: A Randomized, Controlled, Phase I Trial

Here, we aimed to investigate the safety and preliminary efficacy of Kartigen^®, a matrix with autologous bone marrow mesenchymal stem cell-derived chondrocyte precursors embedded in atelocollagen. As a surgical graft, Kartigen^® was implanted onto the cartilage defects at the weight-bearing site of the medial femoral condyle of the knee. Fifteen patients were enrolled and stratified into two groups, undergoing either Kartigen^® implantation (n = 10) or microfracture (control group, n = 5). The primary endpoint was to evaluate the safety of Kartigen^® by monitoring the occurrence of adverse events through physician queries, physical examinations, laboratory tests, and radiological analyses for 2 years. There were no infections, inflammations, adhesions, loose body, or tumor formations in the Kartigen^®-implanted knees. The preliminary efficacy was assessed using the International Knee Documentation Committee (IKDC) score, visual analog scale, and second-look arthroscopy. The postoperative IKDC scores of the Kartigen^® group significantly improved in the 16th week (IKDC = 62.1 ± 12.8, p = 0.025), kept increasing in the first year (IKDC = 78.2 ± 15.4, p < 0.005), and remained satisfactory in the second year (IKDC = 73.6 ± 13.8, p < 0.005), compared to the preoperative condition (IKDC = 47.1 ± 17.0), while the postoperative IKDC scores of the control group also achieved significant improvement in the 28th week (IKDC = 68.5 ± 6.1, p = 0.032) versus preoperative state (IKDC = 54.0 ± 9.1). However, the IKDC scores decreased in the first year (IKDC = 63.5 ± 11.6) as well as in the second year (IKDC = 52.6 ± 16.4). Thirteen patients underwent second-look arthroscopy and biopsy one year after the operation. The Kartigen^® group exhibited integration between Kartigen^® and host tissue with a smooth appearance at the recipient site, whereas the microfracture group showed fibrillated surfaces. The histological and immunohistochemical analyses of biopsy specimens demonstrated the columnar structure of articular cartilage and existence of collagen type II and glycosaminoglycan mimic hyaline cartilage. This study indicates that Kartigen^® is safe and effective in treating cartilage defects.

Arthroscopic Subchondral Drilling Followed by Injection of Peripheral Blood Stem Cells and Hyaluronic Acid Showed Improved Outcome Compared to Hyaluronic Acid and Physiotherapy for Massive Knee Chondral Defects: A Randomized Controlled Trial

PURPOSE

The purpose of this study was to evaluate the safety and efficacy of intra-articular injections of autologous peripheral blood stem cells (PBSCs) plus hyaluronic acid (HA) after arthroscopic subchondral drilling into massive chondral defects of the knee joint and to determine whether PBSC therapy can improve functional outcome and reduce pain of the knee joint better than HA plus physiotherapy.

METHODS

This is a dual-center randomized controlled trial (RCT). Sixty-nine patients aged 18 to 55 years with International Cartilage Repair Society grade 3 and 4 chondral lesions (size ≥3 cm²) of the knee joint were randomized equally into (1) a control group receiving intra-articular injections of HA plus physiotherapy and (2) an intervention group receiving arthroscopic subchondral drilling into chondral defects and postoperative intra-articular injections of PBSCs plus HA. The coprimary efficacy endpoints were subjective International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcome Score (KOOS)-pain subdomain measured at month 24. The secondary efficacy endpoints included all other KOOS subdomains, Numeric Rating Scale (NRS), and Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) scores.

RESULTS

At 24 months, the mean IKDC scores for the control and intervention groups were 48.1 and 65.6, respectively (P < .0001). The mean for KOOS-pain subdomain scores were 59.0 (control) and 86.0 (intervention) with P < .0001. All other KOOS subdomain, NRS, and MOCART scores were statistically significant (P < .0001) at month 24. Moreover, for the intervention group, 70.8% of patients had IKDC and KOOS-pain subdomain scores exceeding the minimal clinically important difference values, indicating clinical significance. There were no notable adverse events that were unexpected and related to the study drug or procedures.

CONCLUSIONS

Arthroscopic marrow stimulation with subchondral drilling into massive chondral defects of the knee joint followed by postoperative intra-articular injections of autologous PBSCs plus HA is safe and showed a significant improvement of clinical and radiologic scores compared with HA plus physiotherapy.

LEVEL OF EVIDENCE

Level I, RCT.

Editorial Commentary: Peripheral Blood Stem Cells Mobilization Using Granulocyte Colony-Stimulating Factor for Articular Cartilage Injuries: Wake Them Up and Make Them Come to You!

Articular cartilage injuries constitute a prevalent musculoskeletal problem in the general population. Restorative cartilage procedures are specifically challenging, as recapitulating hyaline cartilage can be difficult, thus compromising clinical outcomes. Progenitor cells for the treatment of articular cartilage injuries constitute a promising therapeutic method that has been increasing exponentially. Progenitor cells can be obtained from many different human tissues, such as bone marrow, adipose tissue, and muscle, as well as from peripheral blood after mobilizing stem cells from bone marrow with granulocyte colony-stimulating factor simulation. The minimally invasiveness, low complication rate, and efficacy of peripheral blood stem cells has gained significant attention and rapidly has become a promising source of progenitor cell delivery in the past decade.

Using apheresis-derived cells to augment microdrilling in the treatment of chondral defects in an ovine model

The treatment of chondral defects using microdrilling often results in a mechanically weak fibrocartilagenous repair, rather than a more robust hyaline cartilage repair. Many different microfracture/microdrilling augmentation techniques have been described, including the use of cellular products to enhance healing. Autologous peripheral blood progenitor cells can be obtained via apheresis after administration of granulocyte colony-stimulating factor (G-CSF) and have been used successfully to augment microdrilling in clinical patients. The objective of this study was to use apheresis-derived mononuclear blood cells to augment microdrilling treatment of a cartilage defect in an ovine model to determine the effect on healing. Forty adult female sheep were used in this study and were divided into a control group (microdrilling alone) and a treatment group (microdrilling, hyaluronic acid, and apheretic product). Outcome measurements included weight-bearing on the operated limb, macroscopic scoring of the joint, histology, and immunohistochemistry. In addition, magnetic resonance imaging was used to attempt to identify SPION-labeled cells from the apheretic product in the operated limbs. The results showed a significant increase in healing as measured by the modified O'Driscoll sore in the treated group. No evidence of homing of SPION-labeled cells to the defect was found and no correlation was found between the response to G-CSF administration or concentration of CD34⁺  and outcome. A correlation was found between healing and the concentration of white blood cells and peripheral blood mononuclear cell numbers in the apheretic product.

Efficacy and safety of mesenchymal stem cell injections for patients with osteoarthritis: a meta-analysis and review of RCTs

INTRODUCTION

Osteoarthritis (OA), which has a high incidence in the elderly, brings a huge economic burden to society. MSCs (Mesenchymal Stem Cells) have shown great multidirectional differentiation potential which are expected to treat OA, and numerous clinical trials have been conducted. However, the efficacy and safety of the MSCs still need to be further integrated and analyzed.

MATERIALS AND METHODS

We searched several databases (PubMed, EMBASE, Scopus, Web of Science, Cochrane Library, Ovid, and ScienceDirect) for assessing eligible trials that randomized controlled trials, hyaluronic acid as control, and MSCs injection to treat OA. Vitro studies and animal studies were excluded. Search terms were: "cartilage," "clinical trial," "mesenchymal," "stromal" and "stem cell", "osteoarthritis". The preliminary guidelines and study protocol were published online at PROSPERO.

RESULTS

Many assessment scales could not be improved significantly after 6 months. However, most of the scales were significantly improved after 12 months, indicating that compared with hyaluronic acid, stem cells could relieve OA symptoms significantly. No serious adverse effect was found.

CONCLUSION

There are significant therapeutic effects on joint function, symptoms, and no permanent adverse effect has been found after stem cell treatment. It is promising to apply intro-articular injection of stem cells for OA to clinical application. More researches are needed to supplement present deficiencies.

Atelocollagen-Embedded Chondrocyte Precursors as a Treatment for Grade-4 Cartilage Defects of the Femoral Condyle: A Case Series with up to 9-Year Follow-Up

We demonstrated the safety and efficacy of autologous chondrocyte precursor (CP) cell therapy in repairing Grade 4 cartilage defects of medial femoral condyles. The autologous bone marrow mesenchymal stem cells of each participant were isolated, amplified, and then differentiated into CPs in atelocollagen. Neotissues made of CPs were implanted into cartilage defects with an average cell density of 4.9 ± 2.1 × 10⁶ cells/cm² through arthrotomy. The knee function was evaluated with the International Knee Documentation Committee (IKDC) subjective knee form. Patients' knee functions significantly improved by the 28th week (IKDC score = 68.3 ± 12.1), relative to the initial functionality before the CP therapy (IKDC score = 46.1 ± 16.4, p-value = 0.0014). Nine of these twelve patients maintained good knee functions for 9 years post-implantation (IKDC score = 69.8 ± 12.3) at levels higher than the pre-implantation values (p-value = 0.0018). Patients were evaluated with MRI and arthroscopy, and the defective sites exhibited a smooth surface without a gap between the implant and host tissue. This study demonstrates that autologous CPs successfully engraft into the host tissue and result in the re-formation of hyaline-like cartilage, thereby improving the impaired knee functions. Most importantly, no adverse event was reported during this long-term follow-up period.

Autologous Chondrocyte Implantation and Mesenchymal Stem Cells for the Treatments of Chondral Defects of the Knee- A Systematic Review

BACKGROUND

There is still a lack of consensus about the best treatment of chondral defects of the knee. We conducted a systematic PRISMA review to evaluate clinical outcomes of Autologous Chondrocyte Implantation (ACI) and Mesenchymal Stem Cell (MSC) injections for the treatment of focal chondral defects of the knee.

METHODS

A systematic review of literature was performed according to the PRISMA guidelines. All the articles reporting data on ACI and MSC treatments for chondral defects of the knee were considered for inclusion. The main databases were accessed: PubMed, Medline, CINAHL, Cochrane, Embase and Google Scholar. The statistical analysis was performed using the Review Manager Software.

RESULTS

In the p-ACI group (987 knees), the Cincinnati Score improved by 18.94% (p=0.1), VAS by 38% (p=0.01), Tegner score by 19.11% (p=0.03), Lysholm score by 22.40% (p=0.01), IKCD by 27.36% (p=0.003). In the c-ACI group (444 knees), the Cincinnati Score improved by 23.80% (p=0.08), KOOS by 23.48% (p=0.03), VAS by 33.2% (p=0.005), IKDC by 33.30% (p=0.005). In the m-ACI group (599 knees), the Cincinnati Score improved by 26.80% (p=0.08), KOOS by 31.59% (p=0.1), VAS by 30.43% (p=0.4), Tegner score by 23.1% (p=0.002), Lysholm score by 31.14% (p=0.004), IKCD by 30.57% (p<0.001). In the MSCs group (291 knees), the KOOS improved by 29.7% (p=0.003), VAS by 41.89% (p<0.001), Tegner score by 25.81% (p=0.003), Lysholm score by 36.96% (p<0.001), IKCD by 30.57% (p=0.001).

CONCLUSION

Both ACI and MSC therapies can be considered as a concrete solution to treat focal chondral defects of the knee.

Subchondral bone as a novel target for regenerative therapy of osteochondritis dissecans: A case report

BACKGROUND

Osteochondritis dissecans (OCD) is a rare disease of unclear cause characterized by subchondral bone damage and overlying cartilage defects. The current report presents the results of subchondral bone as a novel target for implantation of peripheral blood stem cells (PBSCs) in the treatment of OCD.

CASE SUMMARY

A 16-year-old patient diagnosed with OCD underwent subchondral bone implantation of PBSCs. Four months later, the patient's visual analog scale scores, Western Ontario and McMaster University osteoarthritis index, and whole-organ magnetic resonance imaging score improved significantly, and regeneration of cartilage and subchondral bone was observed on magnetic resonance imaging.

CONCLUSION

This is the first case of OCD treated with subchondral bone as an implantation target of PBSCs, which highlights the importance of subchondral bone for cartilage repair. This treatment could be a potential option for articular cartilage and subchondral bone recovery in OCD.

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.

Chondral Lesions of the Knee: An Evidence-Based Approach

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Management of chondral lesions of the knee is challenging and requires assessment of several factors including the size and location of the lesion, limb alignment and rotation, and the physical and mental health of the individual patient.

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There are a multitude of options to address chondral pathologies of the knee that allow individualized treatment for the specific needs and demands of the patient.

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Osteochondral autograft transfer remains a durable and predictable graft option in smaller lesions (<2 cm2) in the young and active patient population.

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Both mid-term and long-term results for large chondral lesions (≥3 cm2) of the knee have demonstrated favorable results with the use of osteochondral allograft or matrix-associated chondrocyte implantation.

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Treatment options for small lesions (<2 cm2) include osteochondral autograft transfer and marrow stimulation and/or microfracture with biologic adjunct, while larger lesions (≥2 cm2) are typically treated with osteochondral allograft transplantation, particulated juvenile articular cartilage, or matrix-associated chondrocyte implantation.

➤

Emerging technologies, such as allograft scaffolds and cryopreserved allograft, are being explored for different graft sources to address complex knee chondral pathology; however, further study is needed.

Bone Marrow Aspirate Matrix: A Convenient Ally in Regenerative Medicine

The rise in musculoskeletal disorders has prompted medical experts to devise novel effective alternatives to treat complicated orthopedic conditions. The ever-expanding field of regenerative medicine has allowed researchers to appreciate the therapeutic value of bone marrow-derived biological products, such as the bone marrow aspirate (BMA) clot, a potent orthobiologic which has often been dismissed and regarded as a technical complication. Numerous in vitro and in vivo studies have contributed to the expansion of medical knowledge, revealing optimistic results concerning the application of autologous bone marrow towards various impactful disorders. The bone marrow accommodates a diverse family of cell populations and a rich secretome; therefore, autologous BMA-derived products such as the “BMA Matrix”, may represent a safe and viable approach, able to reduce the costs and some drawbacks linked to the expansion of bone marrow. BMA provides —it eliminates many hurdles associated with its preparation, especially in regards to regulatory compliance. The BMA Matrix represents a suitable alternative, indicated for the enhancement of tissue repair mechanisms by modulating inflammation and acting as a natural biological scaffold as well as a reservoir of cytokines and growth factors that support cell activity. Although promising, more clinical studies are warranted in order to further clarify the efficacy of this strategy.

Platelet-Rich Plasma Devices Can Be Used to Isolate Stem Cells From Synovial Fluid at the Point of Care

PURPOSE

To assess whether point-of-care devices designed for collecting cellular components from blood or bone marrow could be used to isolate viable stem cells from synovial fluid.

METHODS

Male and female patients older than 18 years old with either an acute, anterior cruciate ligament (ACL) injury or knee osteoarthritis (OA) with a minimum estimated 20 mL of knee effusion volunteered. Ten patients with an ACL injury and 10 patients with OA were enrolled. Two milliliters of collected synovial effusion were analyzed and cultured for cellular content. The remaining fluid was combined with whole blood and processed using a buffy-coat based platelet-rich plasma (PRP) processing system. Specimens were analyzed for cell counts, colony-forming unit (CFU) assays, differentiation assays, and flow cytometry.

RESULTS

ACL effusion fluid contained 42.1 ± 20.7 CFU/mL and OA effusion fluid contained 65.4 ± 42.1 CFU/mL. After PRP processing, the counts in ACL-PRP were 101.6 ± 66.1 CFU/mL and 114.8 ± 73.4 CFU/mL in the OA-PRP. Cells showed tri-lineage differentiation potential when cultured under appropriate parameters. When analyzed with flow cytometry, >95% of cells produced with culturing expressed cell surface markers typically expressed by known stem cell populations, specifically CD45-, CD73+, CD29+, CD44+, CD105+, and CD90+.

CONCLUSIONS

Multipotent viable stem cells can be harvested from knee synovial fluid, associated with an ACL injury or OA, and concentrated with a buffy coat-based PRP-processing device.

CLINICAL RELEVANCE

PRP devices can be used to harvest stem cells from effusion fluids. Methods to use effusion fluid associated with an ACL injury and OA should be investigated further.

Elevation of Peripheral Blood CD34+ and Platelet Levels After Exercise With Cooling and Compression

Purpose

To analyze the cellular response and chemokine profiles following exercise using cooling and blood flow restriction on the Vasper system.

Methods

Healthy male patients between the ages of 20 and 39 years were recruited. Testing was performed on the Vasper system, a NuStep cross-trainer with concomitant 4-limb venous compression with proximal arm cuffs at 40 mm Hg and proximal leg cuffs at 65 mm Hg. A cooling vest and cooling mat (8.3°C) were used. A 7-minute warm-up followed by alternating 30- and 60-second sprints with 1.5 and 2 minutes of active recovery, respectively, between each sprint. Peripheral blood was drawn before exercise, immediately following exercise (T20), 10 minutes after the first post-exercise blood draw (T30), and then every 30 minutes (T60, T90, T120, T150, T180). A blood draw occurred at 24 hours’ postexercise. Complete blood count, monoclonal flow cytometry for CD34+, and enzyme-linked immunosorbent assay were used to analyze the samples.

Results

Sixteen healthy male patients (29.5 ± 4.5years, 1.78 ± 0.05m, 83.7 ± 11.4 kg) were enrolled. There was an immediate, temporary increase in white blood cell counts, marked by an increase in lymphocyte differential (38.3 ± 6.5 to 44.3 ± 9.0%, P = .001), decrease in neutrophil differential (47.8 ± 6.6 to 42.0 ± 9.1%, P < .001), and platelets (239.5 ± 57.2 to 268.6 ± 86.3 K⋅μL^–1, P = .01). Monocytes significantly decreased from PRE to T90 (9.8 ± 1.1 to 8.9 ± 1.1K/μL, P < .001) and T120 (8.9 ± 1.1 K/μL, P < .0001). There was a significant increase in CD34+ cells (3.9 ± 2.0 to 5.3 ± 2.8 cells⋅μL^–1, P < .001). No detectable differences in measured cytokine levels of interleukin (IL)-10, IL-6, granulocyte-macrophage colony-stimulating factor , IL-1ra, tumor necrosis factor-α, or IL-2 were observed.

Conclusions

A significant elevation of peripheral blood CD34+ and platelet levels immediately following the exercise session was observed; however, there was no effect on peripheral circulation of IL-10, IL-6, IL-1ra, tumor necrosis factor-α, or IL-2.

Clinical Relevance

Exercise can be considered as a way to manipulate point-of-care blood products like platelet-rich plasma and may increase product yield.

Narrative review of the choices of stem cell sources and hydrogels for cartilage tissue engineering

Stem cell-based therapy is a promising treatment for cartilage defects due to the pluripotency, abundant sources and low immunogenicity of stem cells. Hydrogels are a promising class of biomaterials for cartilage engineering and are characterized by bioactivity, degradability and elasticity as well as provide water content and mechanical support. The combination of stem cells and hydrogels opens new possibilities for cartilage tissue engineering. However, the selection of suitable types of stem cells and hydrogels is difficult. Currently, various types of stem cells, such as embryonic stem cells (ESCs), mesenchymal stem cells (MSCs), induced pluripotent stem cells (iPSCs), and peripheral blood mononuclear cells (PBMSCs), and various types of hydrogels, including natural polymers, chemically modified natural polymers and synthetic polymers, have been explored based on their potential for cartilage tissue engineering. These materials are used independently or in combination; however, there is no clear understanding of their merits and disadvantages with regard to their suitability for cartilage repair. In this article, we aim to review recent progress in the use of stem cell-hydrogel hybrid constructs for cartilage tissue engineering. We focus on the effects of stem cell types and hydrogel types on efficient chondrogenesis from cellular, preclinical and clinical perspectives. We compare and analyze the advantages and disadvantages of these cells and hydrogels with the hope of increasing discussion of their suitability for cartilage repair and present our perspective on their use for the improvement of physical and biological properties for cartilage tissue engineering.

Efficacy of mesenchymal stromal cells for the treatment of knee osteoarthritis: a meta-analysis of randomized controlled trials

BACKGROUND

Mesenchymal stromal cells (MSCs) are used as an emerging new option for the treatment of knee osteoarthritis (OA). However, their efficacy remains controversial across studies with different doses of MSCs and cell processing methods. We conducted this meta-analysis to assess the efficacy of MSCs in the treatment of knee OA.

METHODS

Randomized controlled trials (RCTs) published in PubMed, Embase, Web of Science, SinoMed (Chinese BioMedical Literature Service System, China), and CNKI (National Knowledge Infrastructure, China) databases were systematically reviewed. The pain level and function improvements were evaluated using visual analog scale (VAS), McMaster Universities Osteoarthritis Index (WOMAC), and International Knee Documentation Committee (IKDC). The pooled estimate was calculated with weighted mean difference (WMD) with 95% confidence intervals (95%CIs).

RESULTS

Nine RCTs involving 476 patients were included in this meta-analysis. The pooled estimate showed that the treatment of MSCs significantly reduced VAS, WOMAC pain, WOMAC stiffness, and WOMAC function scores at a long-term follow-up (12 or 24 months). However, for the IKDC and WOMAC total scores, MSCs also showed significant improvement in these outcomes, although this was not statistically significant when compared to the control.

CONCLUSION

Based on the current studies, our results suggested that MSCs were a promising option for the treatment of patients with knee OA. However, considering the potential limitations, more well-performed, large-scale RCTs are needed to verify our findings.

Intra-Articular Mesenchymal Stromal Cell Injections Are No Different From Placebo in the Treatment of Knee Osteoarthritis: A Systematic Review and Meta-analysis of Randomized Controlled Trials

PURPOSE

To evaluate the efficacy and safety of intra-articular mesenchymal stromal cells (MSCs) injections for knee osteoarthritis (OA) treatment.

METHODS

We performed a systematic literature search in PubMed, Embase, Scopus, and the Cochrane Library through April 2020 to identify level I randomized controlled trials (RCTs) that evaluated the clinical efficacy of MSCs versus control treatments for knee OA. Outcomes were analyzed on an intention-to-treat basis with random-effects models.

RESULTS

A total of 13 RCTs were included in the meta-analysis. Compared with placebo, there was no significant difference in VAS for pain (mean difference [MD] 1.62, 95% confidence interval [CI -0.60 to 3.85), WOMAC pain score (MD 1.88, 95% CI -0.21 to 3.98), WOMAC function score (MD -0.67, 95% CI -6.54 to 5.19), or WOMAC stiffness score (MD 0.64, 95% CI -0.86 to 2.14) for MSCs. Moreover, the smallest treatment effect of VAS for pain, WOMAC pain score, WOMAC function score, and WOMAC stiffness score did not exceed the minimum clinically important difference (MCID). Additionally, there was no significant difference in percentage of patients crossing the MCID threshold between MSC and placebo groups for VAS for pain (relative risk [RR] 0.93, 95% CI 0.55 to 1.57) or WOMAC total score (RR 0.40, 95% CI 0.13 to 1.21). Compared with hyaluronic acid (HA), MSC injection was associated with significantly better improvement in VAS for pain (MD 2.00, 95% CI 0.94 to 3.07), WOMAC pain score (MD 4.58, 95% CI 0.49 to 8.67), WOMAC total score (MD 14.86, 95% CI 10.59 to 19.13), and WOMAC stiffness score (MD 1.85, 95% CI 0.02 to 3.69). However, the smallest treatment effect of VAS for pain, WOMAC pain score, WOMAC function score, and WOMAC stiffness score did not exceed the MCID. Moreover, there was no significant difference in percentage of patients crossing the MCID threshold between MSC and HA groups for WOMAC total score (RR 0.57, 95% CI 0.21 to 1.55). We also found that MSCs did not increase adverse events compared with HA and placebo.

CONCLUSIONS

Intra-articular MSC injection was not found to be superior to placebo in pain relief and functional improvement for patients with symptomatic knee OA. However, additional direct testing and combination trials of different type of cells, doses, and number of injections of MSCs are required to further enhance clinical decision making for people with symptomatic knee OA.

LEVEL OF EVIDENCE

I, meta-analysis of level I studies.

Accentuating the sources of mesenchymal stem cells as cellular therapy for osteoarthritis knees-a panoramic review

The large economic burden on the global health care systems is due to the increasing number of symptomatic osteoarthritis (OA) knee patients whereby accounting for greater morbidity and impaired functional quality of life. The recent developments and impulses in molecular and regenerative medicine have paved the way for inducing the biological active cells such as stem cells, bioactive materials, and growth factors towards the healing and tissue regenerative process. Mesenchymal stem cells (MSCs) act as a minimally invasive procedure that bridges the gap between pharmacological treatment and surgical treatment for OA. MSCs are the ideal cell-based therapy for treating disorders under a minimally invasive environment in conjunction with cartilage regeneration. Due to the worldwide recognized animal model for such cell-based therapies, global researchers have started using the various sources of MSCs towards cartilage regeneration. However, there is a lacuna in literature on the comparative efficacy and safety of various sources of MSCs in OA of the knee. Hence, the identification of a potential source for therapeutic use in this clinical scenario remains unclear. In this article, we compared the therapeutic effects of various sources of MSCs in terms of efficacy, safety, differentiation potential, durability, accessibility, allogenic preparation and culture expandability to decide the optimal source of MSCs for OA knee.

Erratum: Commentary: Autologous Peripheral Blood Stem Cells (PBSC) are Safe and Effective in Knee Osteoarthritis

[This corrects the article DOI: 10.3389/fphar.2020.00404.].

Evolution of hydrogels for cartilage tissue engineering of the knee: A systematic review and meta-analysis of clinical studies

INTRODUCTION

In recent years, studies have boosted our knowledge about the biology and disorders of articular cartilage. In this regard, the design of hydrogel-based scaffolds has advanced to improve cartilage repair. However, the efficacy of knee cartilage repair using hydrogels remains unclear. The aim of systematic review and meta-analysis was to scrutinize the efficiency of hydrogel-based therapy in correcting cartilage defects of knee (femoral condyle, patella, tibia plateau and trochlea).

METHODS

The search was conducted in PubMed to gather articles published from 2004/1/1 to 2019/10/01, addressing the effects of implant of hydrogel on knee joint cartilage regeneration. The Cochrane Collaboration's tool for estimating the risk of bias was applied to check the quality of articles. The clinical data for meta-analysis was recorded using the visual analog scale (VAS), Lysholm score, WOMAC, and IKDC. The guidelines of Cochrane Handbook for Systematic Reviews of Interventions were utilized to conduct the review and meta-analysis in the RevMan 5.3 software.

RESULTS

The search resulted in 50 clinical trials that included 2846 patients, 986 of whom received cell-based hydrogel implants while 1860 patients used hydrogel without cell. There were significant differences comparing the pain scores based on the VAS (MD: -2.97; 95% CI: -3.15 to -2.79, P<0.00001) and WOMAC (MD: -25.22; 95% CI: -31.22 to -19.22, P<0.00001) between pre- and post-treatment with hydrogels. Furthermore, there were significant improvements in the functional scores based on the IKDC total score (MD: 30.67; P<0.00001) and the Lysholm knee scale (MD: 29.26; 95% CI: 26.74 to 31.78, P<0.00001). According to the Lysholm and IKDC score and after cumulative functional analysis, there was a significant improvement in this parameter (MD: 29.25; 95% CI: 27.26 to 31.25, P<0.00001).

CONCLUSIONS

This meta-analysis indicated clinically and statistically significant improvements in the pain score (VAS and WOMAC) and the functional score (IKDC and Lysholm) after the administration of hydrogel compared to pretreatment status. So, the current evidence shows the efficiency of hydrogel-based therapy in correcting and repairing knee cartilage defects.

Massive Tibial Bone Regeneration with Autologous Peripheral Blood Stem Cells using Ilizarov Bone Transport: A Case Report

This is a case report of a Gustilo-Anderson Type IIIB comminuted open right tibial fracture with massive bone loss, complicated by methicillin-resistant Staphylococus aureus (MRSA) infection. Non-viable and contaminated bony fragments were removed and infected bone resected. Soft tissue coverage and antibiotics were effective against the MRSA infection. A unifocal bone transport with the Ilizarov method regenerated 13cm of the missing tibia. Autologous peripheral blood stem cells (PBSC) injections into the osteogenesis site boosted bone regeneration and consolidation with a shortened Bone Healing index (BHI) of 23 days/cm.

Quantification and Qualification of Stem Cells From Blood After Mobilization With Filgrastim, and Concentration Using a Platelet-Rich Plasma System

PURPOSE

To determine the cellular composition of a product created with peripheral blood harvested after systemic mobilization with filgrastim and processed with one point-of-care blood concentrating system, i.e., a platelet-rich plasma (PRP) system. The second purpose was to compare mobilized platelet-rich plasma (M-PRP) with a concentrated bone marrow aspirate (cBMA) and a PRP created from the same subjects with the same PRP system.

METHODS

Ten healthy volunteer subjects were recruited for collection and analysis of 3 tissue sources: non-treated peripheral blood, bone marrow aspirate, and filgrastim-mobilized peripheral blood, involving 4 doses of weight-based filgrastim. One point-of-care blood and bone marrow concentrating system was used to create 3 products: PRP, cBMA, and M-PRP. Automated hematologic analysis was performed on all products to quantify total red blood cells, white blood cells (WBCs), monocyte, platelet, and hematopoietic progenitor cell (HPC) concentrations. Flow cytometry was used to determine hematopoietic and mesenchymal progenitor cell populations. Lastly, concentrates were cultured and fibroblast colony-forming units (CFU-F) and morphology of adherent cells were evaluated.

RESULTS

M-PRP contained a greater concentration of WBC (mean difference = 53.2 k/μL; P < .0001), monocytes (mean difference = 8.3 k/μL; P = .002), and a trend toward a greater concentration of HPC (mean difference = 200.5 /μL; P = .060) when compared with PRP. M-PRP contained a greater concentration of monocytes (mean difference = 5.5 k/μL; P = .017) and a trend toward a greater concentration of platelets (mean difference = 348 k/μL; P = .051) and HPC (mean difference = 193.4 /μL; P = .068) when compared with cBMA. M-PRP had a similar concentration of platelets to PRP (mean difference = 110 k/μL; P = .051) and PRP had a greater concentration than cBMA (mean difference = 458 k/μL; P = .003). cBMA remained the only product capable of producing CFU-Fs (446 ± 247 /mL) as neither the M-PRP nor PRP produced CFU-Fs. M-PRP produced colonies consistent with WBC.

CONCLUSIONS

M-PRP, produced with filgrastim mobilized blood and a proprietary PRP system, contained more total WBCs, monocytes, platelets, and HPCs than cBMA and more WBCs, monocytes, and HPCs than PRP.

CLINICAL RELEVANCE

Filgrastim mobilized PRP may be an alternative to cBMA for use as a point-of-care product for orthopaedic treatments.

Effect of Stem Cell Injections on Osteoarthritis-related Structural Outcomes: A Systematic Review

OBJECTIVE

To systematically review the evidence for the efficacy of mesenchymal stem cell (MSC) injections in improving osteoarthritis (OA)-related structural outcomes.

METHODS

Ovid Medline and EMBASE were searched from their inceptions to April 2020 using MeSH terms and key words. Independent reviewers extracted data and assessed methodological quality. Qualitative evidence synthesis was performed due to the heterogeneity of interventions and outcome measures.

RESULTS

Thirteen randomized controlled trials (phase I or II) were identified: 10 in OA populations and 3 in populations at risk of OA, with low (n = 9), moderate (n = 3), or high (n = 1) risk of bias. Seven studies used allogeneic MSCs (4 bone marrow, 1 umbilical cord, 1 placenta, 1 adipose tissue), 6 studies used autologous MSCs (3 adipose tissue, 2 bone marrow, 1 peripheral blood). Among the 11 studies examining cartilage outcomes, 10 found a benefit of MSCs on cartilage volume, morphology, quality, regeneration, and repair, assessed by magnetic resonance imaging, arthroscopy, or histology. The evidence for subchondral bone was consistent in all 3 studies in populations at risk of OA, showing beneficial effects. Sixteen unpublished, eligible trials were identified by searching trial registries, including 8 with actual or estimated completion dates before 2016.

CONCLUSION

Our systematic review of early-phase clinical trials demonstrated consistent evidence of a beneficial effect of intraarticular MSC injections on articular cartilage and subchondral bone. Due to the heterogeneity of MSCs, modest sample sizes, methodological limitations, and potential for publication bias, further work is needed before this therapy is recommended in the management of OA.

Expanded mesenchymal stem cell transplantation following marrow stimulation is more effective than marrow stimulation alone in treatment of knee cartilage defect: A systematic review and meta-analysis

BACKGROUND

Articular cartilage defect of the knee is a debilitating disease and marrow stimulation techniques (MST) is typically regarded as the first line of treatment for full thickness cartilage lesions. However, the ability of MST to induce the repair of cartilage defects with fibrocartilage is limited, raising concerns about the durability of the repaired tissue. Mesenchymal stem cells (MSCs) provide an alternative means of treating cartilage defects. Expanded MSCs transplantation following MST has achieved great success in animal studies, but relevant clinical results are still lacking.

HYPOTHESIS

Expanded MSCs transplantation could be an effective adjunctive therapy following MST for knee cartilage defects.

PATIENTS AND METHODS

PubMed, EMBASE, and the Cochrane Library were systematically searched. This investigation considers articles that compare the effectiveness of expanded MSCs transplantation following MST (MSCs/MST) with that of MST alone for treating knee cartilage defects. Data on postoperative clinical outcomes were extracted. In an attempt to analyze trends over time in studies that report repeated measurements, an all time-points meta-analysis (ATM) was undertaken.

RESULTS

Five randomized controlled trials (RCTs) were included in this study. In a pooled analysis, the MSCs/MST group exhibited statistically significantly better postoperative international knee documentation committee subjective knee form (IKDC score) than the MST alone group during two years of follow-up (trend estimate through ATM, 0.27; 95% CI: 0.006 to 0.54). Lysholm scores were similarly favorable to MSCs/MST. The MSCs/MST group also yielded a statistically significantly higher magnetic resonance observation of cartilage repair tissue (MOCART) score at final follow-up (Mean Difference, 16.42; 95% CI: 4.44 to 28.40). No trial has identified serious adverse effects.

DISCUSSION

This meta-analysis demonstrate that expanded MSCs transplantation is a safe and effective adjunctive therapy. Further RCTs with long-term follow up and cost effectiveness analysis are needed.

LEVEL OF EVIDENCE

I, Systematic review and meta-analysis.

Evaluation of autologous adipose-derived mesenchymal stem cell therapy in focal chondral defects of the knee: a pilot case series

Aim: To evaluate the safety, pain, functional and structural improvements after autologous adipose-derived mesenchymal stem cell (ADMSC) therapy in combination with arthroscopic abrasion arthroplasty in focal chondral defects of the knee. Methods: Eight patients with a focal full thickness chondral defect of the knee underwent arthroscopic abrasion arthroplasty followed by postoperative intra-articular injections of autologous ADMSCs (50 × 10⁶ ADMSCs at baseline and 6 months). Clinical outcome was assessed using numeric pain rating scale, Knee Injury and Osteoarthritis Outcome Score and the Western Ontario and McMaster Universities Osteoarthritis Index. Structural outcome was determined by magnetic resonance imaging. Outcome was assessed over 24 months. Results: No serious adverse events occurred. Participants observed clinically significant improvement in pain and function. Magnetic resonance imaging analysis showed cartilage regeneration with T2 mapping values comparable to hyaline cartilage. Conclusion: Arthroscopic abrasion arthroplasty in combination with intra-articular ADMSC therapy results in reproducible pain, functional and structural improvements with regeneration of hyaline-like cartilage. Trial registration number: ACTRN12617000638336.