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OBJECTIVE: To determine whether it is possible to engineer 3-dimensional hyaline cartilage using mesenchymal stem cells derived from the bone marrow (BMSCs) of patients with osteoarthritis (OA). METHODS: Expanded BMSCs derived from patients with hip OA were seeded onto polyglycolic acid scaffolds and differentiated using transforming growth factor beta3 in the presence or absence of parathyroid hormone-related protein (PTHrP) to regulate hypertrophy. Micromass pellet cultures were established using the same cells for comparison. At the end of culture, the constructs or pellets were processed for messenger RNA (mRNA) analysis by quantitative real-time reverse transcription-polymerase chain reaction. Matrix proteins were analyzed using specific assays. RESULTS: Cartilage constructs engineered from BMSCs were at least 5 times the weight of equivalent pellet cultures. Histologic, mRNA, and biochemical analyses of the constructs showed extensive synthesis of proteoglycan and type II collagen but only low levels of type I collagen. The protein content was almost identical to that of cartilage engineered from bovine nasal chondrocytes. Analysis of type X collagen mRNA revealed a high level of mRNA in chondrogenic constructs compared with that in undifferentiated BMSCs, indicating an increased risk of hypertrophy in the tissue-engineered cells. However, the inclusion of PTHrP at a dose of 1 microM or 10 microM during the culture period resulted in significant suppression of type X collagen mRNA expression and a significant decrease in alkaline phosphatase activity, without any loss of the cartilage-specific matrix proteins. CONCLUSION: Three-dimensional hyaline cartilage can be engineered using BMSCs from patients with OA. This method could thus be used for the repair of cartilage lesions. [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is a disabling condition that affects billions of people worldwide and places a considerable burden on patients and on society owing to its prevalence and economic cost. As cartilage injuries are generally associated with the progressive onset of OA, robustly effective approaches for cartilage regeneration are necessary. Despite extensive research, technical development and clinical experimentation, no current surgery-based, material-based, cell-based or drug-based treatment can reliably restore the structure and function of hyaline cartilage. This paucity of effective treatment is partly caused by a lack of fundamental understanding of why articular cartilage fails to spontaneously regenerate. Thus, research studies that investigate the mechanisms behind the cartilage regeneration processes and the failure of these processes are critical to instruct decisions about patient treatment or to support the development of next-generation therapies for cartilage repair and OA prevention. This Review provides a synoptic and structured analysis of the current hypotheses about failure in cartilage regeneration, and the accompanying therapeutic strategies to overcome these hurdles, including some current or potential approaches to OA therapy., (© 2023. Springer Nature Limited.)

Background: Given the high prevalence of Cluster-C Personality Disorders (PDs) in clinical populations, disease burden, high societal costs and poor prognosis of comorbid disorders, a major gain in health care can be achieved if Cluster-C PDs are adequately treated. The only controlled cost-effectiveness study published so far found Individual Schema Therapy (IST) to be superior to Treatment as Usual (TAU). Group ST (GST) might improve cost-effectiveness as larger numbers can be treated in (>50%) less time compared to IST. However, to date there is no RCT supporting its (cost-) effectiveness. The overall aim of this study is to assess the evidence for GST for Cluster-C PDs and to improve treatment allocation for individual patients. Three main questions are addressed: 1) Is GST for Cluster-C PDs (cost-)effective compared to TAU? 2) Is GST for Cluster-C PDs (cost-) effective compared to IST? 3) Which patient-characteristics predict better response to GST, IST, or TAU?, Methods: In a multicenter RCT, the treatment conditions GST, IST, and TAU are compared in 378 Cluster-C PD patients within 10 sites. GST and IST follow treatment protocols and are completed within 1 year. TAU is the optimal alternative treatment available at the site according to regular procedures. Severity of the Cluster-C PD is the primary outcome, assessed with clinical interviews by independent raters blind for treatment. Functioning and wellbeing are important secondary outcomes. Assessments take place at week 0 (baseline), 17 (mid-GST), 34 (post-GST), 51 (post-booster sessions of GST), and 2 years (FU). Patient characteristics predicting better response to a specific treatment are studied, e.g., childhood trauma, autistic features, and introversion. A tool supporting patients and clinicians in matching treatment to patient will be developed. An economic evaluation investigates the cost-effectiveness and cost-utility from a societal perspective. A process evaluation by qualitative methods explores experiences of participants, loved ones and therapists regarding recovery, quality of life, and improving treatment., Discussion: This study will determine the (cost-)effectiveness of treatments for Cluster-C PDs regarding treatment type as well as optimal matching of patient to treatment and deliver insight into which aspects help Cluster-C-PD patients recover and create a fulfilling life., Trial Registration: Dutch Trial Register: NL9209 . Registered on 28-01-2021., (© 2022. The Author(s).)

Targeting stem cells to cartilage lesions has the potential to enhance engraftment and chondrogenesis. Denatured type II collagen fibrils (gelatin) are exposed in lesions at the surface of osteoarthritic articular cartilage and are therefore ideal target sites. We have designed and investigated chimeric mutants of the three modules of the MMP-2 collagen binding domain (CBD) as potential ligands for stem cell targeting. We expressed full-length CBD for the first time and used it to identify the most important amino acid residues for binding to gelatin. Module 2 of CBD had the highest affinity binding to both Type I and Type II gelatin, whereas module 1 showed specificity for type II gelatin and module 3 for type I gelatin. We went on to generate chimeric forms of CBD consisting of three repeats of module 1 (111), module 2 (222) or module 3 (333). 111 lacked solubility and could not be further characterised. However 222 was found to bind to type II gelatin 14 times better than CBD, suggesting it would be optimal for attachment to cartilage lesions, whilst 333 was found to bind to type I gelatin 12 times better than CBD, suggesting it would be optimal for attachment to lesions in type I collagen-rich tissues. We coated 222 onto the external membrane of Mesenchymal Stem Cells and demonstrated higher attachment of the coated cells to type II gelatin than uncoated cells. We conclude that the three modules of CBD each have specific biological properties that can be exploited for targeting stem cells to cartilage lesions and other pathological sites., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Mesenchymal stem cells (MSCs) have been investigated as a potential injectable therapy for the treatment of knee osteoarthritis, with some evidence of success in preliminary human trials. However, optimization and scale-up of this therapeutic approach depends on the identification of functional markers that are linked to their mechanism of action. One possible mechanism is through their chondrogenic differentiation and direct role in neo-cartilage synthesis. Alternatively, they could remain undifferentiated and act through the release of trophic factors that stimulate endogenous repair processes within the joint. Here, we show that extensive in vitro aging of bone marrow-derived human MSCs leads to loss of chondrogenesis but no reduction in trophic repair, thereby separating out the two modes of action. By integrating transcriptomic and proteomic data using Ingenuity Pathway Analysis, we found that reduced chondrogenesis with passage is linked to downregulation of the FOXM1 signaling pathway while maintenance of trophic repair is linked to CXCL12. In an attempt at developing functional markers of MSC potency, we identified loss of mRNA expression for MMP13 as correlating with loss of chondrogenic potential of MSCs and continued secretion of high levels of TIMP1 protein as correlating with the maintenance of trophic repair capacity. Since an allogeneic injectable osteoar therapy would require extensive cell expansion in vitro, we conclude that early passage MMP13 + , TIMP1-secreting high MSCs should be used for autologous OA therapies designed to act through engraftment and chondrogenesis, while later passage MMP13 - , TIMP1-secreting high MSCs could be exploited for allogeneic OA therapies designed to act through trophic repair., (©2020 The Authors. Stem Cells published by Wiley Periodicals LLC on behalf of AlphaMed Press 2020.)

Bioreactor systems will likely play a key role in establishing regulatory compliant and cost-effective production systems for manufacturing engineered tissue grafts for clinical applications. However, the automation of bioreactor systems could become considerably more complex and costly due to the requirements for additional storage and liquid handling technologies if unstable supplements are added to the culture medium. Ascorbic acid (AA) is a bioactive supplement that is commonly presumed to be essential for the generation of engineered cartilage tissues. However, AA can be rapidly oxidized and degraded. In this work, we addressed whether human nasal chondrocytes can redifferentiate, undergo chondrogenesis, and generate a cartilaginous extracellular matrix when cultured in the absence of AA. We found that when chondrocytes were cultured in 3D micromass pellets either with or without AA, there were no significant differences in their chondrogenic capacity in terms of gene expression or the amount of glycosaminoglycans. Moreover, 3D pellets cultured without AA contained abundant collagen Types II and I extracellular matrix. Although the amounts of Collagens II and I were significantly lower (34% and 50% lower) than in pellets cultured with AA, collagen fibers had similar thicknesses and distributions for both groups, as shown by scanning electron microscopy imaging. Despite the reduced amounts of collagen, if engineered cartilage grafts can be generated with sufficient properties that meet defined quality criteria without the use of unstable supplements such as AA, bioreactor automation requirements can be greatly simplified, thereby facilitating the development of more compact, user-friendly, and cost-effective bioreactor-based manufacturing systems., (Copyright © 2018 John Wiley & Sons, Ltd.)

Multipotent mesenchymal stem cells (MSCs) have enormous potential in tissue engineering and regenerative medicine. However, until now, their development for clinical use has been severely limited as they are a mixed population of cells with varying capacities for lineage differentiation and tissue formation. Here, we identify receptor tyrosine kinase-like orphan receptor 2 (ROR2) as a cell surface marker expressed by those MSCs with an enhanced capacity for cartilage formation. We generated clonal human MSC populations with varying capacities for chondrogenesis. ROR2 was identified through screening for upregulated genes in the most chondrogenic clones. When isolated from uncloned populations, ROR2+ve MSCs were significantly more chondrogenic than either ROR2-ve or unfractionated MSCs. In a sheep cartilage-repair model, they produced significantly more defect filling with no loss of cartilage quality compared with controls. ROR2+ve MSCs/perivascular cells were present in developing human cartilage, adult bone marrow, and adipose tissue. Their frequency in bone marrow was significantly lower in patients with osteoarthritis (OA) than in controls. However, after isolation of these cells and their initial expansion in vitro, there was greater ROR2 expression in the population derived from OA patients compared with controls. Furthermore, osteoarthritis-derived MSCs were better able to form cartilage than MSCs from control patients in a tissue engineering assay. We conclude that MSCs expressing high levels of ROR2 provide a defined population capable of predictably enhanced cartilage production. Stem Cells 2017;35:2280-2291., (© 2017 AlphaMed Press.)

Meniscal cartilage tears are common and predispose to osteoarthritis (OA). Most occur in the avascular portion of the meniscus where current repair techniques usually fail. We described previously the use of undifferentiated autologous mesenchymal stem cells (MSCs) seeded onto a collagen scaffold (MSC/collagen-scaffold) to integrate meniscal tissues in vitro. Our objective was to translate this method into a cell therapy for patients with torn meniscus, with the long-term goal of delaying or preventing the onset of OA. After in vitro optimization, we tested an ovine-MSC/collagen-scaffold in a sheep meniscal cartilage tear model with promising results after 13 weeks, although repair was not sustained over 6 months. We then conducted a single center, prospective, open-label first-in-human safety study of patients with an avascular meniscal tear. Autologous MSCs were isolated from an iliac crest bone marrow biopsy, expanded and seeded into the collagen scaffold. The resulting human-MSC/collagen-scaffold implant was placed into the meniscal tear prior to repair with vertical mattress sutures and the patients were followed for 2 years. Five patients were treated and there was significant clinical improvement on repeated measures analysis. Three were asymptomatic at 24 months with no magnetic resonance imaging evidence of recurrent tear and clinical improvement in knee function scores. Two required subsequent meniscectomy due to retear or nonhealing of the meniscal tear at approximately 15 months after implantation. No other adverse events occurred. We conclude that undifferentiated MSCs could provide a safe way to augment avascular meniscal repair in some patients. Registration: EU Clinical Trials Register, 2010-024162-22. Stem Cells Translational Medicine 2017;6:1237-1248., (© 2017 The Authors Stem Cells Translational Medicine published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.)

We present a new approach for the directed delivery of biomolecular payloads to individual cells with high spatial precision. This was accomplished via active sequestration of proteins, oligonucleotides or molecular dyes into coacervate microdroplets, which were then delivered to specific regions of stem cell membranes using a dynamic holographic assembler, resulting in spontaneous coacervate microdroplet-membrane fusion. The facile preparation, high sequestration efficiency and inherent membrane affinity of the microdroplets make this novel "cell paintballing" technology a highly advantageous option for spatially-directed cell functionalization, with potential applications in single cell stimulation, transfection and differentiation.

Restricted oxygen diffusion can result in central cell necrosis in engineered tissue, a problem that is exacerbated when engineering large tissue constructs for clinical application. Here we show that pre-treating human mesenchymal stem cells (hMSCs) with synthetic membrane-active myoglobin-polymer-surfactant complexes can provide a reservoir of oxygen capable of alleviating necrosis at the centre of hyaline cartilage. This is achieved through the development of a new cell functionalization methodology based on polymer-surfactant conjugation, which allows the delivery of functional proteins to the hMSC membrane. This new approach circumvents the need for cell surface engineering using protein chimerization or genetic transfection, and we demonstrate that the surface-modified hMSCs retain their ability to proliferate and to undergo multilineage differentiation. The functionalization technology is facile, versatile and non-disruptive, and in addition to tissue oxygenation, it should have far-reaching application in a host of tissue engineering and cell-based therapies.

Chondrogenic progenitor populations, including mesenchymal stem cells, represent promising cell-based transplantation or tissue engineering therapies for the regeneration of damaged cartilage. Osteoarthritis (OA) predominantly affects the elderly and is a leading cause of disability worldwide. Advancing age is a prominent risk factor that is closely associated with the onset and progression of the disease. Understanding the influence that aging and OA have on chondrogenic progenitor cells is important to determine how these processes affect the cellular mechanisms of the cells and their capacity to differentiate into functional chondrocytes for use in therapeutic applications. Here, we review the effect of age- and OA-related changes on the growth kinetics and differentiation potential of chondrogenic progenitor cell populations. Aging differentially influences the proliferative potential of progenitor cells showing reduced growth rates with increased senescence and apoptotic activity over time, while chondrogenesis appears to be independent of donor age. Cartilage tissue affected by OA shows evidence of progenitor populations with some potential for repair, however reports on the proliferative propensity of mesenchymal stem cells and their chondrogenic potential are contradictory. This is likely attributed to the narrow age ranges of samples assessed and deficits in definitively identifying donors with OA versus healthy patients across a wide scope of advancing ages. Further studies that investigate the mechanistic effects of chondrogenic progenitor populations associated with aging and the progression of OA using clearly defined criteria and age-matched control subject groups are crucial to our understanding of the clinical relevance of these cells for use in cartilage repair therapies.

Cartilage injuries and osteoarthritis are leading causes of disability in developed countries. The regeneration of damaged articular cartilage using cell transplantation or tissue engineering holds much promise but requires the identification of an appropriate cell source with a high proliferative propensity and consistent chondrogenic capacity. Human fetal mesenchymal stem cells (MSCs) have been isolated from a range of perinatal tissues, including first-trimester bone marrow, and have demonstrated enhanced expansion and differentiation potential. However, their ability to form mature chondrocytes for use in cartilage tissue engineering has not been clearly established. Here, we compare the chondrogenic potential of human MSCs isolated from fetal and adult bone marrow and show distinct differences in their responsiveness to specific growth factors. Transforming growth factor beta 3 (TGFβ3) induced chondrogenesis in adult but not fetal MSCs. In contrast, bone morphogenetic protein 2 (BMP2) induced chondrogenesis in fetal but not adult MSCs. When fetal MSCs co-stimulated with BMP2 and TGFβ3 were used for cartilage tissue engineering, they generated tissue with type II collagen and proteoglycan content comparable to adult MSCs treated with TGFβ3 alone. Investigation of the TGFβ/BMP signaling pathway showed that TGFβ3 induced phosphorylation of SMAD3 in adult but not fetal MSCs. These findings demonstrate that the initiation of chondrogenesis is modulated by distinct signaling mechanisms in fetal and adult MSCs. This study establishes the feasibility of using fetal MSCs in cartilage repair applications and proposes their potential as an in vitro system for modeling chondrogenic differentiation and skeletal development studies.

Those working in the regenerative medicine field currently face numerous regulatory and related challenges. This Perspective captures some of the key ideas of a UK-based working group drawn from academic, clinical and industrial communities and also identifies some key steps that should be taken in the UK and elsewhere to address these challenges.

Introduction: The American College of Sports Medicine prescribes regular performance of at least moderate-intensity physical activity for healthy aging. This study examined whether 1 session of 30 min of chair-assisted exercises for the elderly meets this intensity criterion., Method: This cross-sectional study included 47 cognitively healthy volunteers (mean age 84 years). During the performance of 30 min of chair-assisted exercises the authors determined oxygen uptake (VO2), carbon dioxide production, heart rate (HR), and rating of perceived exertion (RPE). These measures were expressed as a percentage of the estimated maximal VO2 (VO2max) and the estimated maximal HR (HRmax) and estimated as metabolic equivalent units (METs)., Results: Participants performed chair-assisted exercises at 61.0% ± 14.7% of VO2max, 67.6% ± 11.3% HRmax, 3.9 ± 0.9 METs, and 13.1 ± 2.1 RPE., Conclusions: The intensity of these chair-assisted exercises is at least moderate for older adults, which is necessary for healthy aging.

Biomaterials that can stimulate stem cell differentiation without growth factor supplementation provide potent and cost-effective scaffolds for regenerative medicine. We hypothesize that a scaffold prepared from cellulose and silk blends can direct stem cell chondrogenic fate. We systematically prepared cellulose blends with silk at different compositions using an environmentally benign processing method based on ionic liquids as a common solvent. We tested the effect of blend compositions on the physical properties of the materials as well as on their ability to support mesenchymal stem cell (MSC) growth and chondrogenic differentiation. The stiffness and tensile strength of cellulose was significantly reduced by blending with silk. The characterized materials were tested using MSCs derived from four different patients. Growing MSCs on a specific blend combination of cellulose and silk in a 75:25 ratio significantly upregulated the chondrogenic marker genes SOX9, aggrecan, and type II collagen in the absence of specific growth factors. This chondrogenic effect was neither found with neat cellulose nor the cellulose/silk 50:50 blend composition. No adipogenic or osteogenic differentiation was detected on the blends, suggesting that the cellulose/silk 75:25 blend induced specific stem cell differentiation into the chondrogenic lineage without addition of the soluble growth factor TGF-β. The cellulose/silk blend we identified can be used both for in vitro tissue engineering and as an implantable device for stimulating endogenous stem cells to initiate cartilage repair.