Stimulates Chondrocyte Proliferation Research Articles

Efficacy and mechanisms of curcumin in the treatment of osteoarthritis: A scoping review

Osteoarthritis (OA) is a degenerative joint disease that primarily affects the elderly worldwide. It is characterized by local inflammation, which can be targeted therapeutically using natural anti-inflammatory compounds such as curcumin. This scoping review explores the therapeutic effects and mechanisms of curcumin in OA management. A total of 50 relevant original studies published in English were selected from PubMed, Web of Science, and Scopus using specific search strings, regardless of study type. These studies demonstrated curcumin’s anti-inflammatory, protective, and anti-apoptotic effects on chondrocytes. Curcumin has been shown to stimulate chondrocyte proliferation and collagen production while inhibiting matrix metalloproteinase activity. These mechanisms contribute to curcumin's ability to alleviate pain and improve joint function in OA patients. While the findings highlight curcumin’s potential in OA management, further research is needed to enhance its bioavailability and determine optimal formulations, dosages, and administration routes.

The role of Clec11a in bone construction and remodeling.

Bone is a dynamically active tissue whose health status is closely related to its construction and remodeling, and imbalances in bone homeostasis lead to a wide range of bone diseases. The sulfated glycoprotein C-type lectin structural domain family 11 member A (Clec11a) is a key factor in bone mass regulation that significantly promotes the osteogenic differentiation of bone marrow mesenchymal stem cells and osteoblasts and stimulates chondrocyte proliferation, thereby promoting longitudinal bone growth. More importantly, Clec11a has high therapeutic potential for treating various bone diseases and can enhance the therapeutic effects of the parathyroid hormone against osteoporosis. Clec11a is also involved in the stress/adaptive response of bone to exercise via mechanical stimulation of the cation channel Pieoz1. Clec11a plays an important role in promoting bone health and preventing bone disease and may represent a new target and novel drug for bone disease treatment. Therefore, this review aims to explore the role and possible mechanisms of Clec11a in the skeletal system, evaluate its value as a potential therapeutic target against bone diseases, and provide new ideas and strategies for basic research on Clec11a and preventing and treating bone disease.

Integrated Network Pharmacology and Experimental Validation Approach to Investigate the Mechanisms of Radix Rehmanniae Praeparata - Angelica Sinensis - Radix Achyranthis Bidentatae in Treating Knee Osteoarthritis.

Knee osteoarthritis (KOA) is a persistent degenerative condition characterized by the deterioration of cartilage. The Chinese herbal formula Radix Rehmanniae Praeparata- Angelica Sinensis-Radix Achyranthis Bidentatae (RAR) has often been used in effective prescriptions for KOA as the main functional drug, but its underlying mechanism remains unclear. Therefore, network pharmacology and verification experiments were employed to investigate the impact and mode of action of RAR in the treatment of KOA. The destabilization of the medial meniscus model (DMM) was utilized to assess the anti-KOA effect of RAR by using gait analysis, micro-computed tomography (Micro-CT), and histology. Primary chondrocytes were extracted from the rib cartilage of a newborn mouse. The protective effects of RAR on OA cells were evaluated using a CCK-8 assay. The antioxidative effect of RAR was determined by measuring reactive oxygen species (ROS), superoxide dismutase (SOD), and glutathione (GSH) production. Furthermore, network pharmacology and molecular docking were utilized to propose possible RAR targets for KOA, which were further verified through experiments. In vivo, RAR significantly ameliorated DMM-induced KOA characteristics, such as subchondral bone sclerosis, cartilage deterioration, gait abnormalities, and the degree of knee swelling. In vitro, RAR stimulated chondrocyte proliferation and the expression of Col2a1, Comp, and Acan. Moreover, RAR treatment significantly reduced ROS accumulation in an OA cell model induced by IL-1β and increased the activity of antioxidant enzymes (SOD and GSH). Network pharmacology analysis combined with molecular docking showed that Mapk1 might be a key therapeutic target. Subsequent research showed that RAR could downregulate Mapk1 mRNA levels in IL-1β-induced chondrocytes and DMM-induced rats. RAR inhibited extracellular matrix (ECM) degradation and oxidative stress response via the MAPK signaling pathway in KOA, and Mapk1 may be a core target.

Young human plasma-derived extracellular vesicles rescue and reactivate IL-1β and TNF-α treated chondrocytes

Osteoarthritis (OA) is a degenerative disease that affects millions of individuals worldwide. Despite its prevalence, the exact causes and mechanisms behind OA are still not fully understood, resulting in a lack of effective treatments to slow down or halt disease progression. Recent research has discovered that extracellular vesicles (EVs) present in the circulation of young mice have a remarkable ability to activate musculoskeletal stem cells in elderly mice. Conversely, EVs derived from elderly mice do not exhibit the same potential, indicating that EVs obtained from young individuals may hold promise to activate aging cells in degenerative tissue. However, it remains unknown whether EVs derived from young individuals can also address cartilage degeneration caused by aging. In this study, we first evaluated EVs derived from young human plasma (YEVs) and EVs derived from old human plasma (OEVs) in an in vitro experiment using chondrocytes. The results revealed that YEVs effectively stimulated chondrocyte proliferation and migration, while OEVs from old plasma did not exhibit a similar effect. Given that OA represents a more complex inflammatory microenvironment, we further determine whether the benefits of YEVs on chondrocytes can be maintained in this context. Our findings indicate that YEVs have the ability to positively regulate chondrocyte function and protect them against apoptosis induced by IL-1β and TNF-α in an in vitro OA model. Furthermore, we discovered that lyophilized EVs could be stored under mild conditions without any alterations in their physical characteristics. Considering the exceptional therapeutic effects and the wide availability of EVs from young plasma, they hold significant promise as a potential approach to activate chondrocytes and promote cartilage regeneration in early-stage OA.

MiR-29a-3p mediates phosphatase and tensin homolog and inhibits osteoarthritis progression.

Despite substantial progress in clinical trials of osteoarthritis (OA) gene therapy, the prevalence of OA is still on the rise. MiRNAs have a potential biomarker and therapeutic target for OA. OA cartilage and chondrosarcoma cells were studied to determine the role of miR-29a-3p and PTEN. OA cartilage and human chondrosarcoma cells (SW1353) were obtained. miR-29a-3p and PTEN signature expression was determined by RT-qPCR. The binding relationship between miR-29a-3p and PTEN was investigated by dual-luciferase reporter gene and western blot assay. TUNEL, immunohistochemistry, CCK-8, and flow cytometry were utilized to determine the proliferation and apoptosis of SW1353 cells. This study indicated downregulation of miR-29a-3p expression and upregulation of PTEN expression in human OA primary chondrocytes or OA tissue samples, compared with the normal cartilage cells or tissues. PTEN expression was negatively correlated with miR-29a-3p expression, and miR-29a-3p targeted PTEN mechanistically. miR-29a-3p reduced SW1353 cell activity and proliferation and promoted cell apoptosis. However, the aforementioned effects could be reversed by downregulating PTEN. miR-29a-3p can stimulate chondrocyte proliferation and inhibit apoptosis by inhibiting PTEN expression.

Injectable Ozone-Rich Nanocomposite Hydrogel Loaded with D-Mannose for Anti-Inflammatory and Cartilage Protection in Osteoarthritis Treatment.

Osteoarthritis (OA) is a dynamic condition characterized by cartilage damage and synovial inflammation. Ozone (O3) shows potential therapeutic effects owing to its anti-inflammatory properties; however, its high reactivity and short half-life substantially limit its effectiveness in OA treatment. In this study, an ozone-rich thermosensitive nanocomposite hydrogel loaded with D-mannose is developed for OA treatment. Briefly, O3 is encapsulated in nanoparticles (NPs) composed of perfluorotributylamine and fluorinated hyaluronic acid to improve its stability. Next, D-mannose is conjugated with α-amino of the hydroxypropyl chitin (HPCH) via Schiff base to prepare MHPCH. These nanoparticles are encapsulated in MHPCH to produce O3 NPs@MHPCH. In vitro cell experiments demonstrate that the O3 NPs@MHPCH treatment significantly reduced VEGF and inflammation levels, accompanied by a decrease in inflammatory factors such as IL-1β, IL-6, TNF-α, and iNOS. Furthermore, O3 NPs@MHPCH promotes the expression of collagen II and aggrecan and stimulates chondrocyte proliferation. Additionally, in vivo studies show that O3 NPs@MHPCH significantly alleviated OA by reducing synovial inflammation, cartilage destruction, and subchondral bone remodeling. O3 NPs@MHPCH offers a promising option for improving the efficacy of O3 therapy and reducing the risk of synovial inflammation and cartilage degeneration in OA.

Down-regulation of long noncoding RNA HULC inhibits the inflammatory response in ankylosing spondylitis by reducing miR-556-5p-mediated YAP1 expression

ObjectiveAnkylosing spondylitis (AS) is a progressive systemic disease characterized by a chronic inflammatory response in the sacroiliac joints and spine. Long noncoding RNAs suggest significant actions in the progression of AS. Therefore, a specific lncRNA, highly upregulated in liver cancer (HULC), was studied here regarding its functions and related mechanisms in AS.MethodsMeasurements of miR-556-5p, HULC, and YAP1 expression were performed on AS cartilage tissues and chondrocytes. The interaction between miR-556-5p and HULC or YAP1 was verified. CCK-8, flow cytometry and enzyme-linked immunosorbent assay were used to evaluate the effects of HULC, miR-556-5p, and YAP1 on the proliferation, apoptosis, and inflammatory response of AS chondrocytes. Furthermore, the action of HULC/miR-556-5p/YAP1 was experimentally observed in AS mice.ResultsHULC and YAP1 levels were augmented, while miR-556-5p levels were suppressed in AS cartilage tissues and chondrocytes. Downregulating HULC or upregulating miR-556-5p stimulated chondrocyte proliferation and inhibited apoptosis and inflammation in AS. miR-556-5p was a downstream factor of HULC, and YAP1 was a potential target of miR-556-5p. The improvement effect of downregulated HULC on AS chondrocytes was saved when YAP1 expression was forced. In addition, silence of HULC improved the pathological injury of spinal cartilage in AS mice by enhancing miR-556-5p-related regulation of YAP1.ConclusionHULC inhibition relieves the inflammatory response in AS by reducing miR-556-5p-mediated YAP1 expression.

3D-bioprinted cell-laden hydrogel with anti-inflammatory and anti-bacterial activities for tracheal cartilage regeneration and restoration

Despite the notable advances in tissue-engineered tracheal cartilage (TETC), there remain several challenges that need to be addressed, such as uneven cell distribution for cartilage formation, customized C-shaped tracheal morphology, local inflammatory reactions, and infections. To overcome these challenges, this study proposed the addition of icariin (ICA) and chitosan (CS) into a gelatin methacryloyl (GelMA) hydrogel to develop a new ICA/CS/GelMA hydrogel with anti-inflammatory and anti-bacterial properties, and three-dimensional (3D)-bioprinting feasibility. The aim of this study was to construct a TETC, a customized C-shaped cartilage structure, with uniform chondrocyte distribution as well as anti-inflammatory and anti-bacterial functions. Our results confirmed that ICA/CS/GelMA hydrogel provides desirable rheological properties, suitable printability, favorable biocompatibility, and simulated microenvironments for chondrogenesis. Moreover, the addition of ICA stimulated chondrocyte proliferation, extracellular matrix synthesis, and anti-inflammatory ability, while the encapsulation of CS enhanced the hydrogels’ anti-bacterial ability. All these led to the formation of an enhanced TETC after submuscular implantation and an elevated survival rate of experimental rabbits after orthotopic tracheal transplantation. This study provides a reliable cell-laden hydrogel with anti-inflammatory and anti-bacterial activities, suitable printability, and significant advancements in in vivo cartilage regeneration and in situ tracheal cartilage restoration.

Smart nanoengineered electronic-scaffolds based on triboelectric nanogenerators as tissue batteries for integrated cartilage therapy

At present, cartilage defect therapy requires a long-term repair period and does not permit real-time detection of the cartilage repair state named “black box”. Inspired by the electroactive nature of living organisms, next-generation tissue trauma therapy with integrated bioelectronics promises to achieve the desired therapeutic effects. Here, a tissue battery for integrated cartilage therapy was nanoengineered through the on-demand integration of intelligent scaffolds with a porous three-dimensional structure and multi-convex triboelectric nanogenerator (TENG)-based sensor. The proposed cartilage tissue battery is repair-induced, self-powered, highly sensitive, implantable, intelligently degradable, and anti-interference. The sensor based on the contact separation TENG mechanism has a high sensitivity (52.5 V MPa–1) within the pressure range of joint movement (0–1.8 MPa), enabling the tissue battery to in-situ detect the real-time status of cartilage repair in the “black box”. Additionally, in vitro and in vivo experiments demonstrated that the tissue battery converts mechanical energy into electricity to stimulate chondrocyte proliferation in the scaffold, thereby shortening the cartilage repair period. The proposed tissue battery for tissue repair under electrical stimulation is beneficial for reducing pain and treatment costs for patients with cartilage defects and is a promising strategy for bioelectronic implants.

Lin28a induces SOX9 and chondrocyte reprogramming via HMGA2 and blunts cartilage loss in mice.

Articular cartilage has low regenerative capacity despite permanent stress. Irreversible cartilage lesions characterize osteoarthritis (OA); this is not followed by tissue repair. Lin28a, an RNA binding protein, is detected in damaged cartilage in humans and mice. We investigated the role of LIN28a in cartilage physiology and in osteoarthritis. Lin28a-inducible conditional cartilage deletion up-regulated Mmp13 in intact mice and exacerbated the cartilage destruction in OA mice. Lin28a-specific cartilage overexpression protected mice against cartilage breakdown, stimulated chondrocyte proliferation and the expression of Prg4 and Sox9, and down-regulated Mmp13. Lin28a overexpression inhibited Let-7b and Let-7c miRNA levels while RNA-sequencing analysis revealed five genes of transcriptional factors regulated by Let-7. Moreover, Lin28a overexpression up-regulated HMGA2 and activated SOX9 transcription, a factor required for chondrocyte reprogramming. HMGA2 siRNA knockdown inhibited the cartilage protective effect of Lin28a overexpression. This study provides insights into a new pathway including the Lin28a-Let7 axis, thus promoting chondrocyte anabolism in injured cartilage in mice.

Mechanically Derived Tissue Stromal Vascular Fraction Acts Anti-inflammatory on TNF Alpha-Stimulated Chondrocytes In Vitro.

Enzymatically isolated stromal vascular fraction (SVF) has already shown to be effective as a treatment for osteoarthritis (OA). Yet, the use of enzymes for clinical purpose is highly regulated in many countries. Mechanical preparation of SVF results in a tissue-like SVF (tSVF) containing intact cell–cell connections including extracellular matrix (ECM) and is therefore less regulated. The purpose of this study was to investigate the immunomodulatory and pro-regenerative effect of tSVF on TNFα-stimulated chondrocytes in vitro. tSVF was mechanically derived using the Fractionation of Adipose Tissue (FAT) procedure. Characterization of tSVF was performed, e.g., cellular composition based on CD marker expression, colony forming unit and differentiation capacity after enzymatic dissociation (from heron referred to as tSVF-derived cells). Different co-cultures of tSVF-derived cells and TNFα-stimulated chondrocytes were analysed based on the production of sulphated glycosaminoglycans and the anti-inflammatory response of chondrocytes. Characterization of tSVF-derived cells mainly contained ASCs, endothelial cells, leukocytes and supra-adventitial cells. tSVF-derived cells were able to form colonies and differentiate into multiple cell lineages. Co-cultures with chondrocytes resulted in a shift of the ratio between tSVF cells: chondrocytes, in favor of chondrocytes alone (p < 0.05), and IL-1β and COX2 gene expression was upregulated in TNFα-treated chondrocytes. After treatment with (a conditioned medium of) tSVF-derived cells, IL-1β and COX2 gene expression was significantly reduced (p < 0.01). These results suggest mechanically derived tSVF stimulates chondrocyte proliferation while preserving the function of chondrocytes. Moreover, tSVF suppresses TNFα-stimulated chondrocyte inflammation in vitro. This pro-regenerative and anti-inflammatory effect shows the potential of tSVF as a treatment for osteoarthritis.

Fibroblast growth factor receptor 1-bound extracellular vesicle as novel therapy for osteoarthritis.

Osteoarthritis (OA) is a joint condition that causes significant impairment of the chondrocyte. The gradual degradation of the cartilage lining of one or more freely moving joints, as well as persistent inflammation, are the causes of osteoarthritis. Current medications focus on alleviating symptoms rather than curing the condition. The aim of this review is to evaluate the potential use of fibroblast growth factor receptor 1-bound extracellular vesicle as novel therapy for osteoarthritis. This review article was completed by searching for the keywords “Fibroblast Growth Factor Receptor 1”, “Extracellular Vesicle”, and “Osteoarthritis” in various journals in several search engines. Of the 102 scientific articles found, 95 were found suitable to be used as material in the making of this article. The upregulated amount of FGFR1 (fibroblast growth factor receptors) signalling suggesting the progression of degenerative cartilage that commonly seen in osteoarthritis (OA) patients. Several studies showed that the involvement of extracellular vesicles (EV) derived from MSCs could enhance cartilage repair and protect the cartilage from degradation. EVs have the potential to deliver effects to specific cell types through ligand-receptor interactions and several pathway mechanisms related with the FGFR1. EVs and FGFR1-bound Evs have been postulated in recent years as possible therapeutic targets in human articular cartilage. The protective benefits on both chondrocytes and synoviocytes in OA patients can be achieved by administering the MSC-EVs that may also stimulate chondrocyte proliferation and migration EVs have a promising potential to become a novel therapy for treating patients with OA. However, further researches are need to be conducted to discover further the application of this therapy.

Hypoxia-Preconditioned Extracellular Vesicles from Mesenchymal Stem Cells Improve Cartilage Repair in Osteoarthritis.

In the past decade, mesenchymal stem cells (MSCs) have been widely used for the treatment of osteoarthritis (OA), and extracellular vesicles (EVs) may play a major role in the efficacy of this treatment. Hypoxia can change the cargo and biological functions of MSC-derived EVs (MSC-EVs). The aim of the present study was to determine whether the effects of hypoxia-preconditioned MSC-EVs on OA cartilage repair are superior to normoxia-preconditioned MSC-EVs. By using in vitro and in vivo OA models, we verified that hypoxia-preconditioned MSC-EVs improved chondrocyte proliferation and migration and suppressed chondrocyte apoptosis to a greater extent than normoxia-preconditioned MSC-EVs. Furthermore, we found that hypoxia altered the microRNA expression in MSC-EVs and identified four differentially expressed microRNAs: hsa-miR-181c-5p, hsa-miR-18a-3p, hsa-miR-376a-5p, and hsa-miR-337-5p. Bioinformatics analysis revealed that hypoxic pretreatment may promote cartilage repair by stimulating chondrocyte proliferation and migration and suppressing chondrocyte apoptosis through the miRNA-18-3P/JAK/STAT or miRNA-181c-5p/MAPK signaling pathway. Therefore, hypoxia-preconditioned EVs may be a novel treatment for OA.

Functional outcome after arthroscopic debridement with microfracture and platelet rich-plasma injection in osteoarthritis of knee – A prospective study

Surgical treatment for knee osteoarthritis (OA) involves debridement, lavage, and microfracture to enhance chondral resurfacing by providing a suitable environment for tissue regeneration. Platelet-rich plasma (PRP) stimulates chondrocyte proliferation. Combining microfracture with PRP injections helps promote early clinical improvement, and this study aims to assess the functional outcomes when all three techniques are used simultaneously. This prospective, observational, hospital-based study was conducted at R. L. Jalappa Hospital and Research Centre, SDUMC, Tamaka, involving patients with OA of the knee from June 2020 to November 2020. Clinical data were collected and evaluated with pre -and post-procedure Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and visual analogue scale (VAS) scores. In all, 74.29% of the patients had Kellgren-Lawrence grade III knee OA and 25.71% had grade II knee OA. The levels of pain and knee function were evaluated using WOMAC and VAS scores before and 1, 3, and 6 months after the procedure. It was observed that 68.57% had good VAS scores, while 31.43% had poor scores. The mean WOMAC scores showed a statistically significant improvement (P &lt; 0.001) with a decrease in the preoperative WOMAC score from 67.11 ± 8.73 to 50.14 ± 9.99 at 1 month, 40.83 ± 7.8 at 3 months, and 31.66 ± 5.28 at 6 months. Intra-articular PRP injection after debridement and microfracture is beneficial for pain relief and functional improvement and prolongs the treatment efficacy of microfracture in patients with symptomatic knee OA.

Fibroblast growth factor receptor 1 extracellular vesicle as novel therapy for osteoarthritis

Introduction Osteoarthritis (OA) is a joint condition that causes significant impairment of the chondrocyte. The gradual degradation of the cartilage lining of one or more freely moving joints, as well as persistent inflammation, are the causes of osteoarthritis. Current medication focuses on alleviating symptoms rather than curing the condition. Methods This review article was completed by searching for information with the keywords “Fibroblast Growth Factor Receptor-1”, “Extracellular Vesicle”, and “Osteoarthritis” in various journals in several search engines. Out of 102 publications found, 95 were suitable to be studied. Results The upregulated amount of fibroblast growth factor receptors (FGFR1) signaling suggesting the progression of degenerative cartilage that commonly seen in osteoarthritis (OA) patients. Several studies showed that the involvement of extracellular vesicles (EV) derived from MSCs could enhance cartilage repair and protect the cartilage from degradation. EVs have the potential to deliver effects to specific cell types through ligand-receptor interactions and several pathway mechanisms related with the FGFR1. EVs and FGFR1 have been postulated in recent years as possible therapeutic targets in human articular cartilage. Conclusions The protective benefits on both chondrocytes and synoviocytes in OA patients can be achieved by administering the MSC-EVs that may also stimulate chondrocyte proliferation and migration. EVs have a promising potential to become a novel therapy for treating patients with OA. However, further research is needed to discover possible application of this therapy.

Molecular Mechanisms of Chondrocyte Proliferation and Differentiation.

Cartilage is a kind of connective tissue that buffers pressure and is essential to protect joint movement. It is difficult to self-recover once cartilage is damaged due to the lack of blood vessels, lymph, and nerve tissues. Repair of cartilage injury is mainly achieved by stimulating chondrocyte proliferation and extracellular matrix (ECM) synthesis. Cartilage homeostasis involves the regulation of multiple growth factors and the transduction of cellular signals. It is a very complicated process that has not been elucidated in detail. In this review, we summarized a variety of signaling molecules related to chondrocytes function. Especially, we described the correlation between chondrocyte-specific regulatory factors and cell signaling molecules. It has potential significance for guiding the treatment of cartilage injury.

Platelet-Rich Plasma Does Not Inhibit Inflammation or Promote Regeneration in Human Osteoarthritic Chondrocytes In Vitro Despite Increased Proliferation.

ObjectiveThe aims of the study were to assess the anti-inflammatory properties of platelet-rich plasma (PRP) and investigate its regenerative potential in osteoarthritic (OA) human chondrocytes. We hypothesized that PRP can modulate the inflammatory response and stimulate cartilage regeneration.DesignPrimary human chondrocytes from OA knees were treated with manually prepared PRP, after which cell migration and proliferation were assessed. Next, tumor necrosis factor-α–stimulated chondrocytes were treated with a range of concentrations of PRP. Expression of genes involved in inflammation and chondrogenesis was determined by real-time polymerase chain reaction. In addition, chondrocytes were cultured in PRP gels and fibrin gels consisting of increasing concentrations of PRP. The production of cartilage extracellular matrix (ECM) was assessed. Deposition and release of glycosaminoglycans (GAG) and collagen was quantitatively determined and visualized by (immuno)histochemistry. Proliferation was assessed by quantitative measurement of DNA.ResultsBoth migration and the inflammatory response were altered by PRP, while proliferation was stimulated. Expression of chondrogenic markers COL2A1 and ACAN was downregulated by PRP, independent of PRP concentration. Chondrocytes cultured in PRP gel for 28 days proliferated significantly more when compared with chondrocytes cultured in fibrin gels. This effect was dose dependent. Significantly less GAGs and collagen were produced by chondrocytes cultured in PRP gels when compared with fibrin gels. This was qualitatively confirmed by histology.ConclusionsPRP stimulated chondrocyte proliferation, but not migration. Also, production of cartilage ECM was strongly downregulated by PRP. Furthermore, PRP did not act anti-inflammatory on chondrocytes in an in vitro inflammation model.

Osteochondral Autograft Plugs versus Paste Graft: Ex Vivo Morselization Increases Chondral Matrix Production.

Patients undergoing articular cartilage paste grafting have been shown in studies to have significant improvement in pain and function in long-term follow-ups. We hypothesized that ex vivo impacting of osteochondral autografts results in higher chondrocyte matrix production versus intact osteochondral autograft plugs. This institutional review board-approved study characterizes the effects of impacting osteochondral plugs harvested from the intercondylar notch of 16 patients into a paste, leaving one graft intact as a control. Cell viability/proliferation, collagen type I/II, SOX-9, and aggrecan gene expression via qRT-PCR (quantitative reverse transcription-polymerase chain reaction) were analyzed at 24 and 48 hours. Matrix production and cell morphology were evaluated using histology. Paste samples from patients (mean age 39.7) with moderate (19%) to severe (81%) cartilage lesions displayed 34% and 80% greater cell proliferation compared to plugs at 24 and 48 hours post processing, respectively (P = 0.015 and P = 0.021). qRT-PCR analysis yielded a significant (P = 0.000) increase of aggrecan, SOX-9, collagen type I and II at both 24 and 48 hours. Histological examination displayed cell division throughout paste samples, with accumulation of aggrecan around multiple chondrocyte lacunae. Paste graft preparation resulted in increased mobility of chondrocytes by matrix disruption without loss of cell viability. The impaction procedure stimulated chondrocyte proliferation resulting in a cellular response to reestablish native extracellular matrix. Analysis of gene expression supports a regenerative process of cartilage tissue formation and contradicts long-held beliefs that impaction trauma leads to immediate cell death. This mechanism of action translates into clinical benefit for patients with moderate to severe cartilage damage.

Platelet lysate is beneficial for chondrocyte expansion but ineffective in 3d culture

Purpose: The purpose of this study is to define the potential of platelet lysate as a xeno-free alternative in expansion of human chondrocytes for cell therapy purposes. Additionally, the effects of using platelet lysate for redifferentiation of chondrocytes in 3D pellets are assessed. Methods: Platelet lysate was prepared from human blood and platelet enrichment was measured. Chondrocytes were isolated from human osteoarthritic cartilage (age 55-84, mean 66 years) and subjected to a range of concentrations of platelet lysate in monolayer culture. Cell proliferation and morphology were assessed after 7 days. In addition, expression of chondrogenic genes was determined by quantitative real-time PCR. Next, platelet lysate-expanded chondrocytes (passage 2) were cultured in 3D cell pellets without any additional growth factors and cartilage matrix production was assessed after 28 days. Glycosaminoglycan (GAG) and collagen production in the pellets were quantified by biochemical analyses as well as (immuno)histochemistry. Moreover, platelet lysate was supplemented into redifferentiation medium of chondrocytes in 3D pellets. Cartilage matrix production was assessed with similar outcomes. Results: Platelet lysate had a dose-dependent effect on chondrocyte proliferation, but expression of chondrogenic markers was decreased in monolayers when compared to bovine serum-expanded monolayers. After 28 days of subsequent 3D pellet culture, GAG production was significantly higher in pellets consisting of chondrocytes expanded with 1% platelet lysate compared to controls (figure 1). When used for redifferentiation of chondrocyte pellets, platelet lysate significantly decreased the production of GAGs and collagen. This was confirmed by (immuno)histochemistry. Conclusions: In conclusion, low concentrations of platelet lysate stimulate chondrocyte proliferation in 2D monolayer and cartilage extracellular matrix production in subsequent 3D pellet culture. However, this does not work for high concentrations of platelet lysate. Furthermore, this study showed unfavourable effects on redifferentiation of 3D chondrocyte cultures in platelet lysate. Thus, platelet lysate can be seen as a promising xeno-free alternative to be used for in vitro expansion of chondrocytes for cartilage tissue engineering or cartilage repair therapies.

Evaluation of CD34+ hematopoietic stem cell-associated extracellular vesicles as a potential personalized therapy for osteoarthritis

Purpose: Platelet-rich plasma (PRP) injections for knee osteoarthritis (OA) are used increasingly in attempts to improve knee functional status and symptoms. Although platelet-derived growth factors are thought to stimulate chondrocyte proliferation, leading to cartilage repair, the mechanisms of action and main effectors of PRP are not fully understood. Plasma contains a high amount of circulating extracellular vesicles (EVs), which are released by almost all mammalian cells, including platelets and stem cells, and that carry surface markers and effectors (e.g.