Repair of chronic osteochondral defects in the rat. A bone marrow-stimulating procedure enhanced by cultured allogenic bone marrow mesenchymal stromal cells

Mesenchymal Stem Cell Extracellular Vesicles as Adjuvant to Bone Marrow Stimulation in Chondral Defect Repair in a Minipig Model

OBJECTIVE

This study evaluated the effects of mesenchymal stem cell-extracellular vesicles (MSC-EVs) on chondrocyte proliferation in vitro and on cartilage repair in vivo following bone marrow stimulation (BMS) of focal chondral defects of the knee.

METHODS

Six adult Göttingen minipigs received 2 chondral defects in each knee. The pigs were randomized to treatment with either BMS combined with MSC-EVs or BMS combined with phosphate-buffered saline (PBS). Intraarticular injections MSC-EVs or PBS were performed immediately after closure of the surgical incisions, and at 2 and 4 weeks postoperatively. Repair was evaluated after 6 months with gross examination, histology, histomorphometry, immunohistochemistry, and micro-computed tomography (µCT) analysis of the trabecular bone beneath the defect.

RESULTS

Defects treated with MSC-EVs had more bone in the cartilage defect area than the PBS-treated defects (7.9% vs. 1.5%, P = 0.02). Less than 1% of the repair tissue in both groups was hyaline cartilage. International Cartilage and Joint Preservation Society II histological scoring showed that defects treated with MSC-EVs scored lower on "matrix staining" (20.8 vs. 50.0, P = 0.03), "cell morphology" (35.4 vs. 53.8, P = 0.04), and "overall assessment" (30.8 vs. 52.9, P = 0.03). Consistently, defects treated with MSC-EVs had lower collagen II and higher collagen I areal deposition. Defects treated with MSC-EVs had subchondral bone with significantly higher tissue mineral densities than PBS-treated defects (860 mg HA/cm3 vs. 838 mg HA/cm3, P = 0.02).

CONCLUSION

Intraarticular injections of MSC-EVs in conjunction with BMS led to osseous ingrowth that impaired optimal cartilage repair, while enhancing subchondral bone healing.

Effects of adipose tissue-derived stromal vascular fraction on osteochondral defects treated by hyaluronic acid-based scaffold: An experimental study

OBJECTIVES

This study aims to evaluate the effect of adipose-derived stromal vascular fraction (SVF) on osteochondral defects treated by hyaluronic acid (HA)-based scaffold in a rabbit model.

MATERIALS AND METHODS

Eighteen white New Zealand rabbits were randomly grouped into the experimental group (n=9) and control group (n=9). In all groups, osteochondral defects were induced on the weight-bearing surfaces of the right femoral medial condyles, and a HA-based scaffold was applied to the defect area with microfractures (MFs). In this study, 1 mL of adipose-derived SVF was injected into the knee joints of the rabbits in the experimental group. For histological and macroscopic evaluation, four rabbits were randomly selected from each group at Week 4, and the remaining rabbits were sacrificed at the end of Week 8. Macroscopic assessments of all samples were performed based on the Brittberg scoring system, and microscopic evaluations were performed based on the O'Driscoll scores.

RESULTS

Samples were taken at Weeks 4 and 8. At Week 4, the O'Driscoll scores were significantly higher in the control group than the experimental group (p=0.038), while there was no significant difference in the Brittberg scores between the two groups (p=0.108). At Week 8, the O'Driscoll score and Brittberg scores were statistically higher in the experimental group than in the control group (p=0.008 and p=0.007, respectively). According to the microscopic evaluation, at the end of Week 8, the cartilage thickness was greater in the experimental group, and nearly all of the defect area was filled with hyaline cartilage.

CONCLUSION

Application of adipose-derived SVF with MF-HA-based scaffold was better than MF-HA-based scaffold treatment in improving osteochondral regeneration. Therefore, it can be used in combination with microfracture and scaffold to accelerate cartilage regeneration, particularly in the treatment of secondary osteoarthritis.

Machine learning to predict mesenchymal stem cell efficacy for cartilage repair

Inconsistent therapeutic efficacy of mesenchymal stem cells (MSCs) in regenerative medicine has been documented in many clinical trials. Precise prediction on the therapeutic outcome of a MSC therapy based on the patient's conditions would provide valuable references for clinicians to decide the treatment strategies. In this article, we performed a meta-analysis on MSC therapies for cartilage repair using machine learning. A small database was generated from published in vivo and clinical studies. The unique features of our neural network model in handling missing data and calculating prediction uncertainty enabled precise prediction of post-treatment cartilage repair scores with coefficient of determination of 0.637 ± 0.005. From this model, we identified defect area percentage, defect depth percentage, implantation cell number, body weight, tissue source, and the type of cartilage damage as critical properties that significant impact cartilage repair. A dosage of 17 - 25 million MSCs was found to achieve optimal cartilage repair. Further, critical thresholds at 6% and 64% of cartilage damage in area, and 22% and 56% in depth were predicted to significantly compromise on the efficacy of MSC therapy. This study, for the first time, demonstrated machine learning of patient-specific cartilage repair post MSC therapy. This approach can be applied to identify and investigate more critical properties involved in MSC-induced cartilage repair, and adapted for other clinical indications.

Regenerative effects of hyperbaric oxygen therapy and platelet-rich plasma on the osteochondral defects of rats

Objectives

This study aims to investigate the effects of hyperbaric oxygen (HBO) therapy and platelet-rich plasma (PRP) on the regeneration of osteochondral defects of the rats, and the synergistic effect of this combined treatment.

Materials and methods

This randomized, controlled, and interventional animal study was conducted between May 2014 and August 2014 Osteochondral regeneration was evaluated in four treatment groups (control, PRP, HBO, and HBO+PRP groups) at the 30th day after iatrogenic injury. Thirty-two female Wistar albino rats (weighing 248-305 g) underwent arthrotomy and osteochondral surgery on left knees. The regenerations of defects were then examined histologically by the modified version of O’Driscoll score.

Results

Groups that were treated with either HBO or PRP alone regenerated significantly better than the control group (p=0.01), while no significant difference was found between the HBO- and PRP-treated groups (p>0.05). The defects in group 4 (treated with both HBO and PRP) regenerated significantly better than the control group, the HBO-treated group alone, and the PRP-treated group alone (p=0.01).

Conclusion

The results of this study showed a synergistic effect of HBO and PRP on knee cartilage regeneration. However, the possible underlying mechanisms should be the subject of future researches. The aggregation and activation of growth factors released from platelets whose activation is increased in the hyperbaric environment may explain this effect. This may result in a better regeneration than the effect of PRP or HBO alone.

Stem cell-directed therapies for osteoarthritis: The promise and the practice

Osteoarthritis (OA) is a disease of an entire synovial joint characterized by clinical symptoms and distortion of joint tissues, including cartilage, muscles, ligaments, and bone. Although OA is a disease of all joint tissues, it is a defined accessible compartment and is thus amenable to topical surgical and regenerative therapies, including stem cells. All tissues arise from stem progenitor cells, and the relative capacity of different cellular compartments, and different individuals, to renew tissues into adulthood may be important in the onset of many different degenerative diseases. OA is driven by both mechanical and inflammatory factors, but how these factors affect the proliferation and differentiation of cells into cartilage in vivo is largely unknown. Indeed, our very basic understanding of the physiological cellular kinetics and biology of the stem-progenitor cell unit of the articular cartilage, and how this is influenced by mechano-inflammatory injury, is largely unknown. OA seems, rather deceptively, to be the low-hanging fruit for stem cell therapy. Without the basic understanding of the stem cell and progenitor unit that generate and maintain articular cartilage in vivo, we will continue to waste opportunities to both prevent and manage this disease. In this review, we discuss the biology of chondrogenesis, the stem cell populations that support articular cartilage in health and disease, and future opportunities afforded through the translation of basic articular chondrocyte stem cell biology into new clinical therapies.

Transplantation of autologous bone marrow-derived mesenchymal stem cells under arthroscopic surgery with microfracture versus microfracture alone for articular cartilage lesions in the knee: A multicenter prospective randomized control clinical trial

Introduction

To investigate the efficacy of the transplantation of autologous bone marrow-derived mesenchymal stem cells (BMSCs) under arthroscopy with microfracture (MFX) compared with microfracture alone.

Methods

Eleven patients with a symptomatic articular cartilage defect of the knee were included in the study. They were randomized to receive BMSCs with MFX (cell-T group, n=7) or MFX alone (control group, n=4). Clinical results were evaluated using International Knee Documentation committee (IKDC) knee evaluation questionnaires and the Knee Injury and Osteoarthritis Outcome Score (KOOS) before and 48 weeks after surgery. Quantitative and qualitative assessments of repair tissue were carried out at 48 weeks by T2 mapping of magnetic resonance images (MRIs) and the magnetic resonance observation of cartilage repair tissue (MOCART) scoring system with follow-up MRI.

Results

No significant differences between preoperative and postoperative IKDC and KOOS were observed in the cell-T or control group. However, forty-eight weeks after surgery, the cell-T group showed a trend for a greater KOOS QOL score compared with the control group (79.4 vs. 39.1, respectively; P=0.07). The T2 value did not differ significantly between the two groups, but the mean MOCART score was significantly higher in the cell-T group than in the control group (P=0.02).

Conclusions

Compared with MFX alone, BMSC transplantation with MFX resulted in better postoperative healing of the cartilage and subchondral bone as determined by the MOCART score. Clinically, BMSC transplantation with MFX gave a higher KOOS QOL score after 48 weeks.

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This is the first prospective randomized clinical trial between BMSCs with MFX and MFX alone.

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BMSCs with MFX showed a trend for a greater KOOS QOL score compared with MFX alone.

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BMSCs with MFX resulted in better healing of the cartilage by the MOCART score.

Role of Mesenchymal Stem Cells Densities When Injected as Suspension in Joints with Osteochondral Defects

OBJECTIVE

The aim of this study was to evaluate an intraarticular injection of different doses of autologous mesenchymal stem cells (MSCs) for improving repair of midterm osteochondral defect.

DESIGN

At 4 weeks postoperative marrow stimulation model bilaterally (3 mm diameter; 4 mm depth) in the medial femoral condyle, autologous MSCs were injected into knee joint. Twenty-four Japanese rabbits aged 6 months were divided randomly into 4 groups ( n = 6 per group): the control group and and MSC groups including 0.125, 1.25, and 6.25 million MSCs. Repaired tissue was assessed macroscopically and histologically at 4 and 12 weeks after intraarticular injection of MSCs.

RESULTS

At 12 weeks, there was no repair tissue in the control group. The gross appearance of the 1.25 and 6.25 million MSC groups revealed complete repair of the defect with white to pink tissue at 12 weeks. An osteochondral repair was histologically significantly better in the 1.25 and 6.25 million MSC groups than in the control and 0.125 million MSC groups at 4 and 12 weeks, due to presence of hyaline-like tissue in the deep layer at 4 weeks, and at 12 weeks hyaline cartilage formation at the periphery and fibrous tissue containing some chondrocytes in the deep layer of the center of the defect. Subchondral bone was restructured in the 1.25 and 6.25 million MSC groups, although it did not resemble the normal bone.

CONCLUSION

An intraarticular injection of 1.25 or 6.25 million MSCs could promote the repair of subchondral bone, even in the case of midterm osteochondral defect.

The safety and efficacy of magnetic targeting using autologous mesenchymal stem cells for cartilage repair

PURPOSE

A new cell delivery system using magnetic force, termed magnetic targeting, was developed for the accumulation of locally injected cells in a lesion. The aim of this study was to assess the safety and efficacy of mesenchymal stem cell (MSC) magnetic targeting in patients with a focal articular cartilage defect in the knee.

METHODS

MSC magnetic targeting for five patients was approved by the Ministry of Health Labour and Welfare of Japan. Autologous bone marrow MSCs were cultured and subsequently magnetized with ferucarbotran. The 1.0-T compact magnet was attached to a suitable position around the knee joint to allow the magnetic force to be as perpendicular to the surface of the lesion as possible. Then 1 × 10⁷ MSCs were injected into the knee joint. The magnet was maintained in the same position for 10 min after the MSC injection. The primary endpoint was the occurrence of any adverse events. The secondary endpoints were efficacy assessed by magnetic resonance imaging (MRI) T2 mapping and clinical outcomes using the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation and the Knee Injury and Osteoarthritis Outcome Score (KOOS).

RESULTS

No serious adverse events were observed during the treatment or in the follow-up period. Swelling of the treated knee joint was observed from the day after surgery in three of the five patients. The swelling resolved within 2 weeks in two patients. MRI showed that the cartilage defect areas were almost completely filled with cartilage-like tissue. MOCART scores were significantly higher 48 weeks postoperatively than preoperatively (74.8 ± 10.8 vs 27.0 ± 16.8, p = 0.042). Arthroscopy in three patients showed complete coverage of their cartilage defects. Clinical outcome scores were significantly better 48 weeks postoperatively than preoperatively for the IKDC Subjective Knee Evaluation (74.8 ± 17.7 vs 46.9 ± 17.7, p = 0.014) and knee-related quality-of-life (QOL) in the KOOS (53.8 ± 26.4 vs 22.5 ± 30.8, p = 0.012).

CONCLUSION

Magnetic targeting of MSCs was safely performed and showed complete coverage of the defects with cartilage-like tissues and significant improvement in clinical outcomes 48 weeks after treatment. The magnetic targeting of MSCs is useful as a minimally invasive treatment for cartilage repair.

LEVEL OF EVIDENCE

IV.

Magnetic Resonance Imaging Evaluation of Cartilage Repair and Iron Particle Kinetics After Magnetic Delivery of Stem Cells

IMPACT STATEMENT

This study is very important as a preclinical study of magnetic resonance imaging (MRI) assessment after magnetic targeting of mesenchymal stem cells. The findings of this study show that MRI is useful for evaluating the regenerative process of cartilage with magnetic targeting and kinetics of iron particles, and is less invasive without any complications.

Magnetic cell delivery for the regeneration of musculoskeletal and neural tissues

Magnetic targeting is a cell delivery system using the magnetic labeling of cells and the magnetic field; it has been developed for minimally invasive cell transplantation. Cell transplantation with both minimal invasiveness and high efficacy on tissue repair can be achieved by this system. Magnetic targeting has been applied for the transplantation of bone marrow mesenchymal stem cells, blood CD133-positive cells, neural progenitor cells, and induced pluripotent stem cells, and for the regeneration of bone, cartilage, skeletal muscles, and the spinal cord. It enhances the accumulation and adhesion of locally injected cells, resulting in the improvement of tissue regeneration. It is a promising technique for minimally invasive and effective cell transplantation therapy.

Bushenhuoxue Formula Facilitates Articular Cartilage Repair and Attenuates Matrix Degradation by Activation of TGF-β Signaling Pathway

Objective

To investigate the effect and underlying mechanism of Bushenhuoxue (BSHX) formula on articular cartilage repair.

Methods

Twenty-four full-thickness cartilage defect rats were divided into two groups: model group and BSHX group (treated with BSHX formula). Macroscopic observation and histopathological study were conducted after 4- and 8-week treatment. Additionally, we also evaluated chondrocyte proliferation, extracellular matrix (ECM) deposition, cartilage degradation, and chondrocyte hypertrophy-related genes expression in chondrogenic ATDC5 cells cultured in BSHX formula-mediated serum. Moreover, we assessed aforementioned genes expression and pSMAD2/3 protein level in Tgfβr2 siRNA transfected chondrogenic ATDC5 cells in order to address whether BSHX formula exerts cartilage repairing effect through TGF-β signaling.

Results

Neocartilage regeneration promotion effect was observed in cartilage defect rats after BSHX formula treatment, with increases in Col2 and pSMAD2 and decreases in Mmp13 and Runx2. Moreover, cell proliferation, the elevated Col2a1, Aggrecan and pSMAD2/3, reduced Mmp13, Adamts5, Col10a1, and Runx2 expression were also observed in chondrogenic ATDC5 cells cultured in BSHX formula-mediated serum. Besides, the expression alteration of ECM deposition, cartilage degradation, chondrocyte hypertrophy-related genes, and pSMAD2/3 protein levels presented in Tgfβr2 downregulated chondrogenic ATDC5 cells couldn't be adjusted by BSHX formula treatment.

Conclusion

By activation of TGF-β signaling, BSHX formula can promote articular cartilage repair by accelerating chondrocyte proliferation and maintaining chondrocyte phenotype, upregulate ECM accumulation, and inhibit matrix degradation.

Age-dependent differences in response to partial-thickness cartilage defects in a rat model as a measure to evaluate the efficacy of interventions for cartilage repair

The objectives of this study are (1) to examine age-dependent longitudinal differences in histological responses after creation of partial-thickness articular cartilage defects (PTCDs) in rats and to use this model (2) to objectively evaluate the effectiveness of interventions for cartilage repair. Linear PTCDs were created at a depth of 100 μm in the weight-bearing region of the medial femoral condyle in rats of different ages (3 weeks, 6 weeks, 10 weeks and 14 weeks). One day, one week, two weeks, four weeks and twelve weeks after PTCD generation, spontaneous healing was evaluated histologically and immunohistochemically. Effects of interventions comprising mesenchymal stem cells (MSCs) or platelet-rich plasma (PRP) or both on 14-week-old PTCD rats were evaluated and compared with natural courses in rats of other ages. Younger rats exhibited better cartilage repair. Cartilage in 3-week-old and 6-week-old rats exhibited nearly normal restoration after 4-12 weeks. Cartilage in 14-week-old rats deteriorated over time and early signs of cartilage degeneration were observed. With injection of MCSs alone or MSCs + PRP, 14-week-old PTCD rats showed almost the same reparative cartilage as 6-week-old rats. With injection of PRP, 14-week-old PTCD rats showed almost the same reparative cartilage as 10-week-old rats. This model will be of great use to objectively compare the effects of interventions for small cartilage lesions and may help to advance the development of disease-modifying osteoarthritis drugs.

Comparative efficacy of stem cells and secretome in articular cartilage regeneration: a systematic review and meta-analysis

Articular cartilage defect remains the most challenging joint disease due to limited intrinsic healing capacity of the cartilage that most often progresses to osteoarthritis. In recent years, stem cell therapy has evolved as therapeutic strategies for articular cartilage regeneration. However, a number of studies have shown that therapeutic efficacy of stem cell transplantation is attributed to multiple secreted factors that modulate the surrounding milieu to evoke reparative processes. This systematic review and meta-analysis aim to evaluate and compare the therapeutic efficacy of stem cell and secretome in articular cartilage regeneration in animal models. We systematically searched the PubMed, CINAHL, Cochrane Library, Ovid Medline and Scopus databases until August 2017 using search terms related to stem cells, cartilage regeneration and animals. A random effect meta-analysis of the included studies was performed to assess the treatment effects on new cartilage formation on an absolute score of 0-100% scale. Subgroup analyses were also performed by sorting studies independently based on similar characteristics. The pooled analysis of 59 studies that utilized stem cells significantly improved new cartilage formation by 25.99% as compared with control. Similarly, the secretome also significantly increased cartilage regeneration by 26.08% in comparison to the control. Subgroup analyses revealed no significant difference in the effect of stem cells in new cartilage formation. However, there was a significant decline in the effect of stem cells in articular cartilage regeneration during long-term follow-up, suggesting that the duration of follow-up is a predictor of new cartilage formation. Secretome has shown a similar effect to stem cells in new cartilage formation. The risk of bias assessment showed poor reporting for most studies thereby limiting the actual risk of bias assessment. The present study suggests that both stem cells and secretome interventions improve cartilage regeneration in animal trials. Graphical abstract ᅟ.

Transplantation of dedifferentiated fat cell-derived micromass pellets contributed to cartilage repair in the rat osteochondral defect model

BACKGROUND

Mature adipocyte-derived dedifferentiated fat (DFAT) cells possesses the ability to proliferate effectively and the potential to differentiate into multiple linages of mesenchymal tissue; similar to adipose-derived stem cells (ASCs). The purpose of this study is to examine the effects of DFAT cell transplantation on cartilage repair in a rat model of osteochondral defects.

METHODS

Full-thickness osteochondral defects were created in the knees of Sprague-Dawley rats bilaterally. Cartilage-like micromass pellets were prepared from green fluorescent protein (GFP)-labeled rat DFAT cells and subsequently transplanted into the affected right knee of these rats. Defects in the left knee were used as a control. Macroscopic and microscopic changes of treated and control defects were evaluated up to 12 weeks post-treatment with DFAT cells. To observe the transplanted cells, sectioned femurs were immunostained for GFP and type II collagen.

RESULTS

DFAT cells formed micromass pellets expressing characteristics of immature cartilage in vitro. In the DFAT cell-transplanted limbs, the defects were completely filled with white micromass pellets as early as 2 weeks post-treatment. These limbs became smooth at 4 weeks. Conversely, the defects in the control limbs were still not repaired by 4 weeks. Macroscopic ICRS scores at 2 and 4 weeks were significantly higher in the DFAT cells-transplanted limbs compared to those of the control limbs. The modified O'Driscol histological scores for the DFAT cell-transplanted limbs were significantly higher than those of the control limbs at corresponding time points. GFP-positive DAFT cells were detected in the transplanted area at 2 weeks but hardly visible at 12 weeks post-operation.

CONCLUSIONS

Transplantation of DFAT cell-derived micromass pellets contribute to cartilage repair in a rat osteochondral defect model. DFAT cell transplantation may be a viable therapeutic strategy for the repair of osteochondral injuries.

In vivo heterotopic culturing of prefabricated tendon grafts with mechanical stimulation in a sheep model

BACKGROUND

The goal of this study is to investigate the biomechanical and histological properties of in vivo heterotopically prefabricated cruciate ligament replacement grafts with and without mechanical stimulation. The clinical goal is to heterotopically prefabricate a bone-tendon-bone graft for anterior cruciate ligament reconstruction, which allows rapid ingrowth and early full weight bearing.

METHODS

In a sheep model, eight quadriceps tendon grafts were harvested and introduced into culture chambers at their proximal and distal ends. In group S, four tendon-chamber constructs were mechanically stimulated by direct attachment to the quadriceps tendon and patella. In group NS, the same constructs were cultured without proximal attachment. All sheep were sacrificed six weeks postoperatively and the constructs were examined biomechanically and histologically. The healthy contralateral ACL and quadriceps tendon were used as controls.

RESULTS

Macroscopically, no obvious ossification could be observed at the ends of the tendon-chamber constructs six weeks postoperatively. Histologically, the tendon tissue from the mechanically stimulated constructs revealed higher counts of cells and capillaries. However, there was less regular cell distribution and collagen fiber orientation compared to the control group. In addition, osteoblasts and osteogenesis were observed in the prefabricated constructs both with and without mechanical stimulation. Biomechanically, there were no significant differences in stiffness, elongation and ultimate failure load between the groups.

CONCLUSION

In vivo heterotopic culture of prefabricated tendon grafts may have the potential to stimulate osteoblasts and induce osteogenesis. Future studies with longer follow-up and modifications of the surgical technique and culture conditions are desirable.

Definition of a Critical Size Osteochondral Knee Defect and its Negative Effect on the Surrounding Articular Cartilage in the Rat

BACKGROUND

Joint trauma is predisposing to the incidence of osteoarthritis (OA) of the knee. There is a limited knowledge on the impact of posttraumatic osteochondral defects on the whole joint. This study was designed to define a critical size osteochondral defect in the knee of rats and to investigate a possible association between osteochondral defects and degeneration of the surrounding joint surface.

METHODS

Cylindrical osteochondral defects of different sizes were created in the knee joint of rats. The natural course of these lesions was studied by macroscopic observation, histology, and immunohistochemistry. Gene expression of the articular cartilage surrounding the defects in vivo and of articular chondrocytes cultured in vitro in IL1β and fibroblast growth factor 2 (FGF2) supplemented media was evaluated by quantitative polymerase chain reaction (qPCR).

RESULTS

In defects of 0.9 mm diameter, spontaneous joint surface healing was observed but also upward advancing of the subchondral bone plate at 16 weeks. Larger 1.4 mm diameter defects were critical size, not resulting in successful healing at any time point. Importantly, the articular cartilage surrounding the defects expressed FGF2 and IL1β, but not ACAN and Col2. Chondrocytes cultured in IL1β and FGF2 supplemented media lost the natural fibroblast growth factor receptors - FGFr1/FGFr3 balance and showed decreased viability.

CONCLUSIONS

A critical size osteochondral defect was defined as 1.4 mm in diameter in rat. Subchondral bone plate advancement occured rapidly. The articular cartilage surrounding osteochondral defects showed catabolic activity with expression of IL1β, FGF2 and a disturbed FGFr1/FGFr3 balance, potentially initiating a process of early osteoarthritic disease.

Granulocyte macrophage - colony stimulating factor (GM-CSF) significantly enhances articular cartilage repair potential by microfracture

OBJECTIVE

To investigate whether granulocyte macrophage-colony stimulating factor (GM-CSF) can be used to increase the number of mesenchymal stem cells (MSCs) in blood clots formed by microfracture arthroplasty (MFX) and whether it can improve the therapeutic outcome for cartilage repair.

METHODS

Thirty-six New Zealand white rabbits were divided into four groups: (1) control, (2) GM-CSF, (3) MFX, and (4) GM-CSF + MFX. GM-CSF was administrated intravenously (IV) at 10 μg/kg body weight 20 min before the MFX surgery. The repaired tissues were retrieved and examined by histological observation, quantitative assessment, and biochemical assays at 4, 8, and 12 weeks after treatment. The number of MSCs was measured in the blood clots by the colony forming unit-fibroblast (CFU-F) assay. The kinetic profile and distribution of GM-CSF in vivo was also evaluated by near-Infrared (NIR) fluorescence imaging and enzyme-linked immune sorbent assay.

RESULTS

In the histological observations and chemical assays examined at 4, 8, and 12 weeks, the MFX after GM-CSF administration showed better cartilage repair than the one without GM-CSF. The CFU-F assay showed a significantly larger amount of MSCs present in the blood clots of the GM-CSF + MFX group than in the blood clots of the other groups. The blood concentration of GM-CSF peaked at 10 min and decreased back to almost the initial level after a couple of hours. GM-CSF was distributed in many organs including the bone marrow but was not observed clearly in the joint cavity.

CONCLUSION

Intravenous administration of GM-CSF together with MFX could be a promising therapeutic protocol to enhance the repair of cartilage defects.

Quality Evaluation of Human Bone Marrow Mesenchymal Stem Cells for Cartilage Repair

Quality evaluation of mesenchymal stem cells (MSCs) based on efficacy would be helpful for their clinical application. In this study, we aimed to find the factors of human bone marrow MSCs relating to cartilage repair. The expression profiles of humoral factors, messenger RNAs (mRNAs), and microRNAs (miRNAs) were analyzed in human bone marrow MSCs from five different donors. We investigated the correlations of these expression profiles with the capacity of the MSCs for proliferation, chondrogenic differentiation, and cartilage repair in vivo. The mRNA expression of MYBL1 was positively correlated with proliferation and cartilage differentiation. By contrast, the mRNA expression of RCAN2 and the protein expression of TIMP-1 and VEGF were negatively correlated with proliferation and cartilage differentiation. However, MSCs from all five donors had the capacity to promote cartilage repair in vivo regardless of their capacity for proliferation and cartilage differentiation. The mRNA expression of HLA-DRB1 was positively correlated with cartilage repair in vivo. Meanwhile, the mRNA expression of TMEM155 and expression of miR-486-3p, miR-148b, miR-93, and miR-320B were negatively correlated with cartilage repair. The expression analysis of these factors might help to predict the ability of bone marrow MSCs to promote cartilage repair.

Microfracture combined with functional pig peritoneum-derived acellular matrix for cartilage repair in rabbit models

Due to avascular and hypocellular nature of cartilage, repair of articular cartilage defects within synovial joints still poses a significant clinical challenge. To promote neocartilage properties, we established a functional scaffold named APM-E7 by conjugating a bone marrow-derived mesenchymal stem cell (BM-MSC) affinity peptide (E7) onto the acellular peritoneum matrix (APM). During in vitro culture, the APM-E7 scaffold can support better proliferation as well as better differentiation into chondrocytes of BM-MSCs. After implanting into cartilage defects in rabbits for 24weeks, compared with microfracture and APM groups, the APM-E7 scaffolds exhibited superior quality of neocartilage without transplant rejection, according to general observations, histological assessment, synovial fluid analysis, magnetic resonance imaging (MRI) and nanomechanical properties. This APM-E7 scaffold provided a scaffold for cell attachment, which was crucial for cartilage regeneration. Overall, the APM-E7 is a promising biomaterial with low immunogenicity for one-step cartilage repair by promoting autologous connective tissue progenitor (CTP) attachment.

STATEMENT OF SIGNIFICANCE

We report the one-step transplantation of functional acellular peritoneum matrix (APM-E7) with specific mesenchymal stem cell recruitment to repair rabbit cartilage injury. The experimental results illustrated that the APM-E7 scaffold was successfully fabricated, which could specifically recruit MSCs and fill the cartilage defects in the femoral trochlear of rabbits at 24weeks post-surgery. The repaired tissue was hyaline cartilage, which exhibited ideal mechanical stability. The APM-E7 biomaterial could provide scaffold for MSCs and improve cell homing, which are two key factors required for cartilage tissue engineering, thereby providing new insights into cartilage tissue engineering.

The use of mesenchymal stem cells for cartilage repair and regeneration: a systematic review

BACKGROUND

The management of articular cartilage defects presents many clinical challenges due to its avascular, aneural and alymphatic nature. Bone marrow stimulation techniques, such as microfracture, are the most frequently used method in clinical practice however the resulting mixed fibrocartilage tissue which is inferior to native hyaline cartilage. Other methods have shown promise but are far from perfect. There is an unmet need and growing interest in regenerative medicine and tissue engineering to improve the outcome for patients requiring cartilage repair. Many published reviews on cartilage repair only list human clinical trials, underestimating the wealth of basic sciences and animal studies that are precursors to future research. We therefore set out to perform a systematic review of the literature to assess the translation of stem cell therapy to explore what research had been carried out at each of the stages of translation from bench-top (in vitro), animal (pre-clinical) and human studies (clinical) and assemble an evidence-based cascade for the responsible introduction of stem cell therapy for cartilage defects. This review was conducted in accordance to PRISMA guidelines using CINHAL, MEDLINE, EMBASE, Scopus and Web of Knowledge databases from 1st January 1900 to 30th June 2015. In total, there were 2880 studies identified of which 252 studies were included for analysis (100 articles for in vitro studies, 111 studies for animal studies; and 31 studies for human studies). There was a huge variance in cell source in pre-clinical studies both of terms of animal used, location of harvest (fat, marrow, blood or synovium) and allogeneicity. The use of scaffolds, growth factors, number of cell passages and number of cells used was hugely heterogeneous.

SHORT CONCLUSIONS

This review offers a comprehensive assessment of the evidence behind the translation of basic science to the clinical practice of cartilage repair. It has revealed a lack of connectivity between the in vitro, pre-clinical and human data and a patchwork quilt of synergistic evidence. Drivers for progress in this space are largely driven by patient demand, surgeon inquisition and a regulatory framework that is learning at the same pace as new developments take place.

Stem cells in degenerative orthopaedic pathologies: effects of aging on therapeutic potential

PURPOSE

The purpose of this study was to summarize the current evidence on the use of stem cells in the elderly population with degenerative orthopaedic pathologies and to highlight the pathophysiologic mechanisms behind today's therapeutic challenges in stem cell-based regeneration of destructed tissues in the elderly patients with osteoarthritis (OA), degenerative disc disease (DDD), and tendinopathies.

METHODS

Clinical and basic science studies that report the use of stem cells in the elderly patients with OA, DDD, and tendinopathies were identified using a PubMed search. The studies published in English have been assessed, and the best and most recent evidence was included in the current study.

RESULTS

Evidence suggests that, although short-term results regarding the effects of stem cell therapy in degenerative orthopaedic pathologies can be promising, stem cell therapies do not appear to reverse age-related tissue degeneration. Causes of suboptimal outcomes can be attributed to the decrease in the therapeutic potential of aged stem cell populations and the regenerative capacity of these cells, which might be negatively influenced in an aged microenvironment within the degenerated tissues of elderly patients with OA, DDD, and tendinopathies.

CONCLUSIONS

Clinical protocols guiding the use of stem cells in the elderly patient population are still under development, and high-level randomized controlled trials with long-term outcomes are lacking. Understanding the consequences of age-related changes in stem cell function and responsiveness of the in vivo microenvironment to stem cells is critical when designing cell-based therapies for elderly patients with degenerative orthopaedic pathologies.

Effect of Low-Intensity Pulsed Ultrasound after Mesenchymal Stromal Cell Injection to Treat Osteochondral Defects: An In Vivo Study

We investigated the effect of low-intensity pulsed ultrasound (LIPUS) treatment combined with mesenchymal stromal cell (MSC) injection for cartilage repair and subchondral bone reconstitution for treatment of osteochondral defects. An osteochondral defect was created on both femur grooves of Wistar rats. Four weeks later, bone marrow MSCs were injected into the right knee joint. The rats were divided into two intervention groups: without or with LIPUS irradiation. Cartilage repair was evaluated histologically based on the Wakitani cartilage repair score. Subchondral bone reconstitution was evaluated as bone volume (BV)/tissue volume (TV) by micro-computed tomography analysis. MSC injection improved the cartilage repair score, and LIPUS irradiation improved BV/TV. Combination treatment promoted both cartilage repair and BV/TV improvement. Thus, MSC injection combined with LIPUS irradiation is more effective than either treatment alone in promoting concurrent cartilage repair and subchondral reconstitution.

Intraarticular Injection of Allogenic Mesenchymal Stem Cells has a Protective Role for the Osteoarthritis

Background:

Researchers initially proposed the substitution of apoptotic chondrocytes in the superficial cartilage by injecting mesenchymal stem cells (MSCs) intraarticularly. This effect was termed as bio-resurfacing. Little evidence supporting the treatment of osteoarthritis (OA) by the delivery of a MSC suspension exists. The aim of this study was to investigate the effects of injecting allogenic MSCs intraarticularly in a rat OA model and to evaluate the influence of immobility on the effects of this treatment.

Methods:

We established a rat knee OA model after 4 and 6 weeks and cultured primary bone marrow MSCs. A MSC suspension was injected into the articular space once per week for 3 weeks. A subgroup of knee joints was immobilized for 3 days after each injection, while the remaining joints were nonimmobilized. We used toluidine blue staining, Mankin scores, and TdT-mediated dUTP-biotin nick end labeling staining to evaluate the therapeutic effect of the injections. Comparisons between the therapy side and the control side of the knee joint were made using paired t-test, and comparisons between the immobilized and nonimmobilized subgroups were made using the unpaired t-test. A P value < 0.05 was considered significant.

Results:

The three investigative approaches revealed less degeneration on the therapy sides of the knee joints than the control sides in both the 4- and 6-week groups (P < 0.05), regardless of immobilization. No significant differences were observed between the immobilized and nonimmobilized subgroups (P > 0.05).

Conclusions:

Therapy involving the intraarticular injection of allogenic MSCs promoted cartilage repair in a rat arthritis model, and 3-day immobility after injection had little effect on this therapy.

The Effect of Exercise on the Early Stages of Mesenchymal Stromal Cell-Induced Cartilage Repair in a Rat Osteochondral Defect Model

The repair of articular cartilage is challenging owing to the restriction in the ability of articular cartilage to repair itself. Therefore, cell supplementation therapy is possible cartilage repair method. However, few studies have verified the efficacy and safety of cell supplementation therapy. The current study assessed the effect of exercise on early the phase of cartilage repair following cell supplementation utilizing mesenchymal stromal cell (MSC) intra-articular injection. An osteochondral defect was created on the femoral grooves bilaterally of Wistar rats. Mesenchymal stromal cells that were obtained from male Wistar rats were cultured in monolayer. After 4 weeks, MSCs were injected into the right knee joint and the rats were randomized into an exercise or no-exercise intervention group. The femurs were divided as follows: C group (no exercise without MSC injection); E group (exercise without MSC injection); M group (no exercise with MSC injection); and ME group (exercise with MSC injection). At 2, 4, and 8 weeks after the injection, the femurs were sectioned and histologically graded using the Wakitani cartilage repair scoring system. At 2 weeks after the injection, the total histological scores of the M and ME groups improved significantly compared with those of the C group. Four weeks after the injection, the scores of both the M and ME groups improved significantly. Additionally, the scores in the ME group showed a significant improvement compared to those in the M group. The improvement in the scores of the E, M, and ME groups at 8 weeks were not significantly different. The findings indicate that exercise may enhance cartilage repair after an MSC intra-articular injection. This study highlights the importance of exercise following cell transplantation therapy.

Combination therapy with intra-articular injection of mesenchymal stem cells and articulated joint distraction for repair of a chronic osteochondral defect in the rabbit

The present study investigated intra-articular injection of bone-marrow-derived mesenchymal stem cells (MSCs) combined with articulated joint distraction as treatment for osteochondral defects. Large osteochondral defects were created in the weight-bearing area of the medial femoral condyle in rabbit knees. Four weeks after defect creation, rabbits were divided into six groups: control group, MSC group, distraction group, distraction + MSC group, temporary distraction group, and temporary distraction + MSC group. Groups with MSC received intra-articular injection of MSCs. Groups with distraction underwent articulated distraction arthroplasty. Groups with temporary distraction discontinued the distraction after 4 weeks. The rabbits were euthanized at 4, 8, and 12 weeks after treatment except temporary distraction groups which were euthanized at only 12 weeks. Histological scores in the distraction + MSC group were significantly better than in the control, MSC group or distraction group at 4 and 8 weeks, but showed no further improvement. At 12 weeks, the temporary distraction + MSC group showed the best results, demonstrating hyaline cartilage repair with regeneration of the osteochondral junction. In conclusion, joint distraction with intra-articular injection of MSCs promotes early cartilage repair, and compressive loading of the repair tissue after temporary distraction stimulates articular cartilage regeneration.

Cell Magnetic Targeting System for Repair of Severe Chronic Osteochondral Defect in a Rabbit Model

The aim of this study was to investigate a cell delivery system for repair of severe chronic osteochondral defects using magnetically labeled mesenchymal stem cells (m-MSCs), with the aid of an external magnetic device, through the accumulation of a small number of m-MSCs into a desired area and to detect the suitable number of autologous m-MSCs needed for repair of the defect. Twenty-six male Japanese white rabbits aged 6 months were used. An osteochondral defect was created bilaterally at the weight-bearing surface of the medial femoral condyle of the rabbits' knees (3 mm diameter; 4 mm depth). At 4 weeks after creation of the defect, autogenic transplantation of the m-MSCs into the defect area was performed, followed by 10-min exposure to an external magnetic device, where animals were divided into four groups: high (1 × 10(6) m-MSCs), medium (2 × 10(5) m-MSCs), low (4 × 10(4) m-MSCs), and control (PBS injection). At 4 and 12 weeks posttransplantation of m-MSCs, repaired tissue was assessed histologically using the Fortier score with toluidine blue staining. Transplantation of a low number of m-MSCs was not enough to improve osteogenesis and chondrogenesis, but the medium and high groups improved repair of the chronic defect with chondrogenic tissues and showed histologically significantly better results than the control and low groups. The use of a magnetic targeting system for delivering m-MSCs has the potential to overcome the clinical hurdles for repair of the severe chronic osteochondral defect. Furthermore, this system is predicted to produce good clinical outcomes for humans, not only to repair osteochondral defects but also to repair a variety of damaged tissues.

In Vivo Kinetics of Mesenchymal Stem Cells Transplanted into the Knee Joint in a Rat Model Using a Novel Magnetic Method of Localization

We have developed a magnetic system for targeting cells in minimally invasive cell transplantation. Magnetically labeled MSCs (m-MSCs) with nanoscale iron particles can be guided into the desired region by magnetic force from an extracorporeal device. We reported that magnetic targeting of m-MSCs enhances cartilage repair in a mini-pig model. However, the detailed kinetics of these magnetically targeted m-MSCs remain unknown. For clinical use, this aspect should be clarified from a safety standpoint. We therefore investigated the spatial and temporal distribution of the fluorescently-labeled m-MSCs transplanted into the knee joint using in vivo fluorescence combined with three-dimensional computed tomographic imaging in a rat model. Although the intraarticularly injected m-MSCs were spread throughout the joint cavity in the absence of magnetic force, the magnetic force caused the injected m-MSCs to accumulate around the chondral lesion. Further examinations including ex vivo imaging, histological assessments and reverse transcription polymerase chain reaction revealed that transplanted MSCs were not present in any major organs after intraarticular administration, regardless of magnetic targeting. Our data suggest that m-MSCs can be accumulated efficiently into a chondral lesion using our magnetic targeting system, while none of the intraarticularly transplanted MSCs migrate to other major organs.

Mesenchymal stem cells reduce pain but not degenerative changes in a mono-iodoacetate rat model of osteoarthritis

We studied the effects of intra-articularly injected bone marrow derived mesenchymal stem cells (MSCs), as well as freshly isolated bone marrow mononuclear cells (BMMNCs), on pain, cartilage damage, bone changes and inflammation in an in-vivo rat osteoarthritis (OA) model. OA was induced unilaterally by injection of mono-iodoacetate (MIA) and allowed to develop for 3 weeks. Then, animals were treated by intra-articular injection with MSCs, BMMNCs, or saline as a control. Four weeks later, pain was assessed with an incapitance tester, subchondral bone alterations were measured with µCT and cartilage quality and joint inflammation were assessed by histological analysis. Animals treated with MSCs distributed significantly more weight to the affected limb after treatment, which was not observed in the other groups. No statistically significant differences between treatment groups regarding cartilage damage, subchondral bone alterations and synovial inflammation were observed. Additional cell tracking experiments indicated adequate intra-articular cell injection and cell survival up to 2 weeks. In our OA model, injected MSCs were able to reduce MIA induced pain, as measured by an increased weight distribution to the affected limb. No statistically significant effects of the cellular therapies on structural damage and synovial inflammation were found.

Stem cell therapies for knee cartilage repair: the current status of preclinical and clinical studies

BACKGROUND

Articular cartilage damage of the knee is common, causing significant morbidity worldwide. Many adult tissues contain cells that are able to differentiate into multiple cell types, including chondrocytes. These stem cells have gained significant attention over the past decade and may become frontline management for cartilage defects in the very near future.

PURPOSE

The role of stem cells in the treatment of knee osteochondral defects was reviewed. Recent animal and clinical studies were reviewed to determine the benefits and potential outcomes of using stem cells for cartilage defects.

STUDY DESIGN

Literature review.

METHODS

A PubMed search was undertaken. The key phrase "stem cells and knee" was used. The search included reviews and original articles over an unlimited time period. From this search, articles outlining animal and clinical trials were selected. A search of current clinical trials in progress was performed on the clinicaltrials.gov website, and "stem cells and knee" was used as the search phrase.

RESULTS

Stem cells have been used in many recent in vitro and animal studies. A number of cell-based approaches for cartilage repair have progressed from preclinical animal studies into clinical trials.

CONCLUSION

The use of stem cells for the treatment of cartilage defects is increasing in animal and clinical studies. Methods of delivery of stem cells to the knee's cartilage vary from direct injection to implantation with scaffolds. While these approaches are highly promising, there is currently limited evidence of a direct clinical benefit, and further research is required to assess the overall outcome of stem cell therapies for knee cartilage repair.

Current perspectives in stem cell research for knee cartilage repair

Protocols based on the delivery of stem cells are currently applied in patients, showing encouraging results for the treatment of articular cartilage lesions (focal defects, osteoarthritis). Yet, restoration of a fully functional cartilage surface (native structural organization and mechanical functions) especially in the knee joint has not been reported to date, showing the need for improved designs of clinical trials. Various sources of progenitor cells are now available, originating from adult tissues but also from embryonic or reprogrammed tissues, most of which have already been evaluated for their chondrogenic potential in culture and for their reparative properties in vivo upon implantation in relevant animal models of cartilage lesions. Nevertheless, particular attention will be needed regarding their safe clinical use and their potential to form a cartilaginous repair tissue of proper quality and functionality in the patient. Possible improvements may reside in the use of biological supplements in accordance with regulations, while some challenges remain in establishing standardized, effective procedures in the clinics.

Regenerative medicine in orthopedics using cells, scaffold, and microRNA

Cells, scaffold, and growth factors are crucially important in regenerative medicine and tissue engineering. Progress in science and technology has enabled development of these three factors, with basic research being applied clinically. In the past decade, we have investigated tissue regeneration in animal models of musculoskeletal disorders by using cells, scaffold, and delivery systems which has been relatively easy to apply and develop in clinical settings. Moreover, microRNA (miRNA), which are important in biological processes and in the pathogenesis of human diseases, have been used in research on regenerative medicine. For the cell source, we focused on mesenchymal stem cells (MSC) and CD34(+) and CD133(+) cells as endothelial progenitor cells for regeneration of musculoskeletal organs. These cells are accessible and safe. For less invasive and more effective therapy, we developed a novel cell-delivery system using magnetic force to accumulate cells at a desired site. Furthermore, administration of synthetic miRNA could enhance tissue regeneration. In our studies, use of these cells combined with a cell-delivery system, miRNA, scaffold, and cytokines has led to effective regeneration of musculoskeletal tissues including cartilage, bone, ligaments, muscle, peripheral nerves, and spinal cord. The current and future objective is more effective and less invasive cell-based therapy with spatial control of transplanted cells by use of an external magnetic force. Analysis of efficiency, safety, and the mechanism of tissue regeneration by cells, scaffold, and miRNA will lead to more promising regenerative medicine, involving the development of a new generation of therapy. This review will focus on our regenerative medicine research, which focuses on clinical application of cells, scaffold, and miRNA.

Safety reporting on implantation of autologous adipose tissue-derived stem cells with platelet-rich plasma into human articular joints

Background

Adipose tissue-derived stem cells (ADSCs), a type of mesenchymal stem cells (MSCs), have great potential as therapeutic agents in regenerative medicine. Numerous animal studies have documented the multipotency of ADSCs, showing their capabilities to differentiate into tissues such as muscle, bone, cartilage, and tendon. However, the safety of autologous ADSC injections into human joints is only beginning to be understood and the data are lacking.

Methods

Between 2009 and 2010, 91 patients were treated with autologous ADSCs with platelet-rich plasma (PRP) for various orthopedic conditions. Stem cells in the form of stromal vascular fraction (SVF) were injected with PRP into various joints (n = 100). All patients were followed for symptom improvement with visual analog score (VAS) at one month and three months. Approximately one third of the patients were followed up with third month magnetic resonance imaging (MRI) of the injected sites. All patients were followed up by telephone questionnaires every six months for up to 30 months.

Results

The mean follow-up time for all patients was 26.62 ± 0.32 months. The follow-up time for patients who were treated in 2009 and early 2010 was close to three years. The relative mean VAS of patients at the end of one month follow-up was 6.55 ± 0.32, and at the end of three months follow-up was 4.43 ± 0.41. Post-procedure MRIs performed on one third of the patients at three months failed to demonstrate any tumor formation at the implant sites. Further, no tumor formation was reported in telephone long-term follow-ups. However, swelling of injected joints was common and was thought to be associated with death of stem cells. Also, tenosinovitis and tendonitis in elderly patients, all of which were either self-limited or were remedied with simple therapeutic measures, were common as well.

Conclusions

Using both MRI tracking and telephone follow ups in 100 joints in 91 patients treated, no neoplastic complications were detected at any ADSC implantation sites. Based on our longitudinal cohort, the autologous and uncultured ADSCs/PRP therapy in the form of SVF could be considered to be safe when used as percutaneous local injections.

Extended release local anesthetic agents in a postoperative arthritic pain model

Local anesthetics play an important role in postoperative pain management in orthopedic joint procedures. The aim of this study was to determine the effect of an intraoperative extra-articular injection of poly(DL-lactic acid co castor oil 3:7), p(DLLA:CO) 3:7 loaded with 15% bupivacaine, for postoperative analgesia following knee arthroplasty. Prolonged release local anesthetic formulation was synthesized by mixing p(DLLA:CO) 3:7 with bupivacaine base. Under anesthesia, the knee joint of Sprague-Dawley rats was exposed, a hole drilled in the femoral trochlea. 0.2 mL of either 15% polymer-bupivacaine formulation or plain bupivacaine (control) was injected locally and compared with a nonsurgery control group. Mechanical hyperalgesia was determined by counting the vocalizations and leg withdrawal after joint squeezing. Behavioral assessments over a day postoperative period revealed a reduction in rearing and ambulation in an open-field apparatus in animals of both experimental groups compared with the nonsurgery control. The vocalizations during the hyperalgesia test increased compared with the control at 24 h. At 48 h, 3.667 ± 0.5138, p = 0.0076 vocalizations were recorded for the plain bupivacaine group versus 1.417 ± 0.5138, p < 0.0001 in the 15% polymer-bupivacaine formulation. Bupivacaine encapsulated in p(DLLA:CO) 3:7 extended the duration of the analgesia compared with plain drug in rats and could represent effective postoperative analgesic in orthopedic joint procedures.

Articular cartilage repair with magnetic mesenchymal stem cells

BACKGROUND

Cell therapies are hampered by the difficulty of delivering cells to and retaining them in target tissues long enough to repair or regenerate local tissues.

HYPOTHESIS

Magnetic-assisted delivery of magnetically labeled mesenchymal stem cells (m-MSCs) would be rapid, allowing for chondrogenic differentiation and functional joint repair without replacement.

STUDY DESIGN

Controlled laboratory study.

METHODS

Sixteen mini-pigs aged 6 to 7 months were used. A full-thickness cartilage defect was created in the center of the patella with a cylindrical punch (diameter, 6 mm). At 4 weeks after creation of the cartilage defects, the animals were divided into 3 treatment groups: In the M group, m-MSCs (5 × 10(6) cells) were injected and accumulated to the cartilage defect using an external magnetic force (1.5 T) for 10 minutes; in the G group, the patella was faced upward, filled with MSCs (5 × 10(6) cells), and held for 10 minutes; and in the C group, only phosphate-buffered saline was injected. The regenerated cartilage was evaluated in 5 knees in each of the 3 groups by arthroscopic surgery at 6 and 12 weeks and histological and ultrasound evaluation at 12 and 24 weeks.

RESULTS

The mean arthroscopic scores at 6 weeks were 10.4 ± 1.10 in the M group, 8.8 ± 0.84 in the G group, and 7.4 ± 0.89 in the C group. There was a statistically significant difference between the M group and the other 2 groups. The mean arthroscopic scores at 12 weeks were 12.8 ± 1.30 (M group), 10.5 ± 1.30 (G group), and 9.5 ± 0.58 (C group), with a statistically significant difference between the M and C groups. The mean histological scores using the Wakitani scoring system at 12 weeks were 2.8 ± 0.96 (M group), 5.4 ± 0.55 (G group), and 6.0 ± 2.20 (C group), and the mean histological scores at 24 weeks were 2.4 ± 1.50 (M group), 3.5 ± 0.56 (G group), and 5.3 ± 1.50 (C group). The mean histological scores at 12 weeks were significantly better in the M group than in the other groups, and the M group maintained a significantly better histological score than did the C group at 24 weeks.

CONCLUSION

The m-MSCs had no adverse effect on chondrogenic differentiation, and m-MSCs delivered by magnetic field application repaired cartilage defects.

CLINICAL RELEVANCE

The clinical application of this novel stem cell delivery system is a potential therapeutic option for treating cartilage defects and may be more applicable throughout the body than traditional methods.

Osteochondral lesions of the talus: size, age, and predictors of outcomes

In this article, our research on osteochondral lesions of the talus (OLTs) is summarized, the orthopedic literature is reviewed, and the direction of future research and treatment trends are discussed. Our research has explored the role of lesion size, significance of marrow edema, relationship of patient age, importance of lesion containment, and role of a stable cartilage lesion cap in the prognosis and outcomes of these lesions. We have identified smaller sized lesions, younger patients and contained lesions as independent predictors of success for the operative treatment of OLTs. Our data should facilitate the development of a more comprehensive treatment algorithm to more accurately predict success in operative management of these lesions.

Treatment of cartilage defects by subchondral drilling combined with covering with atelocollagen membrane induces osteogenesis in a rat model

BACKGROUND

The coverage of the atelocollagen membrane at the chondral defect after subchondral drilling might improve the beneficial effects for cartilage repair because of the prevention of scattering and accumulation of cells and growth factors from bone marrow within the chondral defect. On the other hand, it might block cells and factors derived from the synovium or cause high pressure in the chondral defect, resulting in prevention of cells and growth factors gushing out from the bone marrow, which leads to disadvantages for cartilage repair.

METHOD

We tested this hypothesis in a 2-mm-diameter chondral defect created in the articular cartilage of the patellar groove in a rat models. Defects were left untreated, or were drilled or drilled and covered with an atelocollagen membrane; healing was evaluated by histology and gene expression analysis using real-time polymerase chain reaction and immunohistochemistry.

RESULTS

Membrane coverage induced bone tissue ingrowth into the punched chondral defect. At 1 week, expression of TGFβ, Sox9, Runx2, osteocalcin, Col1a1, and Col2a1 in the drilling group was significantly higher than in the covering group. At 4 weeks, expressions of TGFβ, Runx2, and Col1a1 were all significantly higher in the drilling group, while Sox9, osteocalcin, and Col2a1 were significantly higher in the covering group. Immunohistochemistry demonstrated Sox9, osteocalcin, and type II collagen on the bony reparative tissue in the covering group.

CONCLUSIONS

These results suggest that the atelocollagen membrane coverage resulted in inhibition of cartilage repair.

Genetic engineering of juvenile human chondrocytes improves scaffold-free mosaic neocartilage grafts

BACKGROUND

Current cartilage transplantation techniques achieve suboptimal restoration and rely on patient donor cells or living grafts of chondrocytes.

PURPOSE

We sought to enhance allogeneic grafts by testing mosaics of genetically engineered and naïve juvenile human chondrocytes (jCh).

METHODS

We obtained specimens from three humans and performed three experiments (two in vitro, one in vivo). We compared neocartilage with and without (1) supplemented serum-free medium (chondrocyte differentiation medium [CDM]), (2) adenoviral BMP-2 (AdBMP-2) transduction, and (3) varying ratios (0.1-1) of transduced and naïve jCh. We compared (4) healing with mosaic grafts with naïve neocartilage or marrow stimulation in immunosuppressed rats. For each of 10 in vitro treatment groups, we had six replicates for each human, and for each of three in vivo treatment groups, we had four replicates for one human. We scored the histology with the semiquantitative Bern score.

RESULTS

AdBMP-2 and naïve neocartilage growth in CDM were histologically superior (Bern score, 5.2 versus 3.7; 8.0 versus 1.8) and size (8.0 versus 6.1; 7.9 versus 2.2 mg) to standard medium. In CDM, AdBMP-2 decreased viability (76% versus 90%), but increased BMP-2 production (619 ng/mL versus 43 pg/mL). Ten percent and 25% AdBMP-2 transduction had Bern scores of 6.8 and 6.5 and viability of 84% and 83%, respectively. Twenty-five percent mosaic grafts provided better healing histologically than marrow stimulation or naive neocartilage.

CONCLUSIONS

Low-level AdBMP-2 and CDM augment neocartilage parameters in vitro and vivo.

CLINICAL RELEVANCE

Genetic augmentation of jCh and creation of mosaic neocartilage may improve graft viability and articular healing compared with naïve neocartilage.

The application of super paramagnetic iron oxide-labeled mesenchymal stem cells in cell-based therapy

Mesenchymal stem cell (MSC)-based therapy has great potential for tissue regeneration. However, being able to monitor the in vivo behavior of implanted MSCs and understand the fate of these cells is necessary for further development of successful therapies and requires an effective, non-invasive and non-toxic technique for cell tracking. Super paramagnetic iron oxide (SPIO) is an idea label and tracer of MSCs. MRI can be used to follow SPIO-labeled MSCs and has been proposed as a gold standard for monitoring the in vivo biodistribution and migration of implanted SPIO-labeled MSCs. This review discusses the biological effects of SPIO labeling on MSCs and the therapeutic applications of local or systemic delivery of these labeled cells.

A Novel, Minimally-Invasive Technique of Cartilage Repair in the Human Knee Using Arthroscopic Microfracture and Injections of Mesenchymal Stem Cells and Hyaluronic Acid—A Prospective Comparative Study on Safety and Short-Term Efficacy

Introduction: Most current cell-based cartilage repair techniques require some form of scaffolds and 2 separate surgical procedures. We propose a novel, scaffold-less technique of cartilage repair in the human knee that combines arthroscopic microfracture and outpatient intra-articular injections of autologous bone marrow-derived mesenchymal stem cells (MSCs) and hyaluronic acid (HA). Materials and Methods: Seventy matched (age, sex, lesion size) knees with symptomatic cartilage defects underwent cartilage repair with the proposed technique (n = 35) or an open technique (n = 35) in which the MSCs were implanted beneath a sutured periosteal patch over the defect. Prospective evaluation of both groups were performed using the International Cartilage Repair Society (ICRS) Cartilage Injury Evaluation Package, which included questions from the Short-Form (SF-36) Health Survey, International Knee Documentation Committee (IKDC) subjective knee evaluation form, Lysholm knee scale, and Tegner activity level scale. Postoperative magnetic resonance imaging (MRI) evaluation was also performed at 1 year for most patients. Results: There were no clinically significant adverse events reported through the course of our study. At the final follow-up (mean = 24.5 months), there was significant improvement in mean IKDC, Lysholm, SF-36 physical component score and visual analogue pain scores in both treatment groups. Conclusion: In the short term, the results of this novel technique are comparable to the open procedure with the added advantages of being minimally invasive and requiring only a single operation under general anaesthesia. Its safety has been validated and its efficacy is currently being evaluated in an ongoing randomised controlled trial. Key words: Chondral, Novel, Osteoarthritis, Regeneration

Mesenchymal stem cells injection in degenerated intervertebral disc: cell leakage may induce osteophyte formation

Recent studies have shown that mesenchymal stem cell (MSC)-based therapy might be an effective approach for the treatment of intervertebral disc degeneration (IDD). However, many unanswered questions remain before clinical translation, such as the most effective stem cell type, a reliable transplantation method, including the carrier choice, and the fate of stem cells after misdirected delivery, among others. The objective of the study was to evaluate the fate and effect of allogenic bone marrow MSCs after transplantation into an IDD model. The L2-3, L3-4 and L4-5 intervertebral discs (IVDs) of four rabbits were stabbed to create IDD. Rabbit MSCs were expanded in vitro and in part transduced with retrovirus/eGFP. After 3 weeks, 1 × 10(5) MSCs were injected into the IVDs. The rabbits were followed by X-ray and MRI 3 and 9 weeks after injection. Then the animals were sacrificed and the spines analysed histologically. MRI showed no signs of regeneration. X-ray and gross anatomy inspection demonstrated large anterolateral osteophytes. Histological analysis showed that the osteophytes were composed of mineralized tissue surrounded by chondrocytes, with the labelled MSCs among the osteophyte-forming cells. The labelled MSCs were not found in the nucleus. Inflammatory cells were not observed in any injected IVDs. These results raise concern that MSCs can migrate out of the nucleus and undesirable bone formation may occur. While cause cannot be inferred from this study, the presence of MSCs in the osteophytes suggests a potential side-effect with this approach. IVD regeneration strategies need to focus on cell carrier systems and annulus-sealing technologies to avoid pitfalls.

Articular cartilage repair using an intra-articular magnet and synovium-derived cells

The purpose of this study was to investigate the chondrogenic potential of magnetically labeled synovium-derived cells (M-SDCs) and examine whether M-SDCs could repair the articular cartilage using an intra-articular magnet after delivery to the lesion. Synovium-derived cells (SDCs) were cultured from the synovium of a rat knee, and were magnetically labeled with ferumoxides. M-SDCs were examined with a transmission electron microscope. A pellet culture system was used to evaluate the chondrogenic potential of M-SDCs in a magnetic field. In a rat model, allogeneic M-SDCs were injected into the knee after we made an osteochondral defect on the patellar groove and implanted an intra-articular magnet at the bottom of the defect. We histologically examined the defects at 48 h, 4 weeks, 8 weeks, and 12 weeks after treatment. Electron microscopy showed the transfection of ferumoxides into SDCs. The pellet cultures revealed the chondrogenic potential of M-SDCs in a magnetic field. M-SDCs accumulated in the osteochondral defect at 48 h after treatment, and we confirmed the regeneration of the articular cartilage at 4 weeks, 8 weeks, and 12 weeks after treatment using an intra-articular magnet. We demonstrated that articular cartilage defects could be repaired using an intra-articular magnet and M-SDCs. We believe that this system will be useful to repair human articular cartilage defects.

Enhancement of bone formation in an experimental bony defect using ferumoxide-labelled mesenchymal stromal cells and a magnetic targeting system

We used interconnected porous calcium hydroxyapatite ceramic to bridge a rabbit ulnar defect. Two weeks after inducing the defect we percutaneously injected rabbit bone marrow-derived mesenchymal stromal cells labelled with ferumoxide. The contribution of an external magnetic targeting system to attract these cells into the ceramic and their effect on subsequent bone formation were evaluated. This technique significantly facilitated the infiltration of ferumoxide-labelled cells into ceramic and significantly contributed to the enhancement of bone formation even in the chronic phase. As such, it is potentially of clinical use to treat fractures, bone defects, delayed union and nonunion.

The influence of skeletal maturity on allogenic synovial mesenchymal stem cell-based repair of cartilage in a large animal model

One of the potential factors that may affect the results of mesenchymal stem cell (MSC)-based therapy is the age of donors and recipients. However, there have been no controlled studies to investigate the influence of skeletal maturity on the MSC-based repair of cartilage. The purpose of this study was to compare the repair quality of damaged articular cartilage treated by a scaffold-free three-dimensional tissue-engineered construct (TEC) derived from synovial MSCs between immature and mature pigs. Synovial MSCs were isolated from immature and mature pigs and the proliferation and chondrogenic differentiation capacities were compared. The TEC derived from the synovial MSCs were then implanted into equivalent chondral defects in the medial femoral condyle of both immature and mature pigs, respectively. The implanted defects were morphologically and biomechanically evaluated at 6 months postoperatively. There was no skeletal maturity-dependent difference in proliferation or chondrogenic differentiation capacity of the porcine synovial MSCs. The TEC derived from synovial MSCs promoted the repair of chondral lesion in both immature and mature pigs without the evidence of immune reaction. The repaired tissue by the TEC also exhibited similar viscoelastic properties to normal cartilage regardless of the skeletal maturity. The results of the present study not only suggest the feasibility of allogenic MSC-based cartilage repair over generations but also may validate the use of immature porcine model as clinically relevant to test the feasibility of synovial MSC-based therapies in chondral lesions.

Variation of mesenchymal cells in polylactic acid scaffold in an osteochondral repair model

OBJECTIVE

To achieve osteochondral regeneration utilizing transplantation of cartilage-lineage cells and adequate scaffolds, it is essential to characterize the behavior of transplanted cells in the repair process. The objectives of this study were to elucidate the survival of mesenchymal cells (MCs). In a polylactic acid (PLA) scaffold and assess the possibility of MC/PLA constructs for osteochondral repair.

DESIGN

Bone marrow from mature male rabbits was cultured for 2 weeks, and fibroblast-like MCs, which contain mesenchymal stem cells (MSCs), were obtained. A cell/scaffold construct was prepared with one million MCs and a biodegradable PLA core using a rotator device. One week after culturing, the construct was transplanted into an osteochondral defect in the medial femoral condyle of female rabbits and the healing process examined histologically. To examine the survivability of transplanted MCs, the male-derived sex-determining region Y (SRY) gene was assessed as a marker of MCs in the defect by polymerase chain reaction (PCR).

RESULTS

In the groups of defects without any treatment, and the transplantation of PLA without cells, the defects were not repaired with hyaline cartilage. The cartilaginous matrix by safranin O staining and type II collagen by immunohistochemical staining were recognized, however the PLA matrix was still present in the defects at 24 weeks after transplantation of the construct. During the time passage, transplanted MCs numbers decreased from 7.8 x 105 at 1 week, to 3.5 x 105 at 4 weeks, and to 3.8 x 104 at 12 weeks. Transplanted MCs were not detectable at 24 weeks.

CONCLUSIONS

MCs contribute to the osteochondral repair expressing the cartilaginous matrix, however the number of MCs were decreasing with time (i.e. 24 weeks). These results could be essential for achieving cartilage regeneration by cell transplantation strategies with growth factors and/or gene therapy.

The effect of an external magnetic force on cell adhesion and proliferation of magnetically labeled mesenchymal stem cells

BACKGROUND

As the strategy for tissue regeneration using mesenchymal stem cells (MSCs) for transplantation, it is necessary that MSCs be accumulated and kept in the target area. To accumulate MSCs effectively, we developed a novel technique for a magnetic targeting system with magnetically labeled MSCs and an external magnetic force. In this study, we examined the effect of an external magnetic force on magnetically labeled MSCs in terms of cell adhesion and proliferation.

METHODS

Magnetically labeled MSCs were plated at the bottom of an insert under the influence of an external magnetic force for 1 hour. Then the inserts were turned upside down for between 1 and 24 hours, and the number of MSCs which had fallen from the membrane was counted. The gene expression of MSCs affected magnetic force was analyzed with microarray. In the control group, the same procedure was done without the external magnetic force.

RESULTS

At 1 hour after the inserts were turned upside down, the average number of fallen MSCs in the magnetic group was significantly smaller than that in the control group, indicating enhanced cell adhesion. At 24 hours, the average number of fallen MSCs in the magnetic group was also significantly smaller than that in control group. In the magnetic group, integrin alpha2, alpha6, beta3 BP, intercellular adhesion molecule-2 (ICAM-2), platelet/endothelial cell adhesion molecule-1 (PECAM-1) were upregulated. At 1, 2 and 3 weeks after incubation, there was no statistical significant difference in the numbers of MSCs in the magnetic group and control group.

CONCLUSIONS

The results indicate that an external magnetic force for 1 hour enhances cell adhesion of MSCs. Moreover, there is no difference in cell proliferation after using an external magnetic force on magnetically labeled MSCs.

Augmentation of degenerated human cartilage in vitro using magnetically labeled mesenchymal stem cells and an external magnetic device

PURPOSE

The purpose of this study was to investigate whether it is possible to regenerate degenerated human cartilage in vitro by use of magnetically labeled mesenchymal stem cells (MSCs) and an external magnetic device.

METHODS

MSCs from human bone marrow were cultured and magnetically labeled. Degenerated human cartilage was obtained during total knee arthroplasty. The osteochondral fragments were attached to the sidewall of tissue culture flasks, and magnetically labeled MSCs were injected into the flasks. By use of an external magnetic device, a magnetic force was applied for 6 hours to the direction of the cartilage, and then the degenerated cartilage was cultured in chondrogenic differentiation medium for 3 weeks. In the control group a magnetic force was not applied. The specimens were evaluated histologically.

RESULTS

A cell layer was formed on the degenerated cartilage as shown by H&E staining. The cell layer was also stained in toluidine blue and safranin O and with anti-collagen type II immunostaining, indicating that the cell layer contained an extracellular matrix. In the control group a cell layer was not observed on the cartilage.

CONCLUSIONS

We were able to show that our system could deliver MSCs onto degenerated human cartilage and then form an extracellular matrix on the degenerated cartilage in vitro.

CLINICAL RELEVANCE

Our novel cell delivery system using magnetic force may lead toward a new treatment option for osteoarthritis.

Analyses of early events during chondrogenic repair in rat full-thickness articular cartilage defects

In this study we investigated the cellular events that occur during the onset of chondrogenic differentiation during the repair of full-thickness defects of articular cartilage. The V-shaped full-thickness cartilage defects (width 0.7 or 1.5 mm; depth 0.8 mm; length 4 mm) were created in the femoral patellar groove of rats using a custom-built twin-blade device. The time course of the repair response in these cartilage defects was examined using a semi-quantitative histological grading scale. Cartilaginous repair responses failed to occur in the larger 1.5 mm defects, which was covered only by fibrous scar tissue. In contrast, hyaline-like articular cartilage was regenerated concomitantly with the repair of the subchondral bone by 4 weeks in smaller 0.7 mm width defects. Cells in the reparative regions were then characterized by immunohistochemistry and in situ hybridization. Undifferentiated mesenchymal cells migrate into the defects and fill the cavities within 4 days of their creation. The expression of PCNA, N-cadherin, and PTH/PTHrP receptors was induced in cells at the center of the defects, where type II collagen-positive polygonal-shaped cells also begin to appear at day 7. Marrow-derived mesenchymal cells acquire higher levels of proliferative activity in induced cartilage cavities after their initial migration and filling of the smaller 0.7 mm defects. During the regenerative repair of articular cartilage in the rat, there is a distinctive step that appears to be analogous to the precartilaginous condensation that is pivotal during chondrogenesis in development.

Multiple drillings of the acetabular fossa induce early joint remodeling after rotational acetabular osteotomy for hip dysplasia

INTRODUCTION

We previously observed medial and/or lateral expansion of the subchondral bone in the acetabulum 3 years postoperatively in two out of three cases in which rotational acetabular osteotomy (RAO) was performed. Then we performed multiple drillings at the acetabular fossa in order to induce expansion of the medial subchondral bone in the acetabulum. The purpose of this study is to evaluate the effect of multiple drillings on early joint remodeling after RAO.

PATIENTS AND METHODS

Twenty-one women (21 joints) who had undergone RAO with multiple drillings at acetabular fossa (group D) were included. As a control group, 12 women (14 joints) without drillings in RAO procedure were observed (group C). The center-edge angle (CE angle), acetabular roof obliquity (AC angle), head lateralization index (HLI), and the angle between medial and lateral edge of acetabular roof (LOM angle) were measured on the radiographs preoperatively, at 1 month, 2 years postoperatively, and at the last follow-up.

RESULTS

As regards the mean CE angle, AC angle, and HLI, there was no significant difference between the two groups. The mean LOM angle at 2 years and the last follow-up demonstrated significant difference between the two groups.

INTERPRETATION

Biomechanical and anatomical changes after RAO cause increasing stress to the medial side of the acetabulum. Moreover, bone marrow-stimulating procedure at acetabular fossa might be beneficial to develop early joint remodeling affected by bone marrow derived cells such as mesenchymal stem cells.

A novel cell delivery system using magnetically labeled mesenchymal stem cells and an external magnetic device for clinical cartilage repair

PURPOSE

The purpose of this study was to investigate whether it is possible to successfully accumulate magnetically labeled mesenchymal stem cells (MSCs), under the direction of an external magnetic force, to the desired portion of osteochondral defects of the patellae after intra-articular injection of the MSCs.

METHODS

MSCs were cultured from bone marrow and were labeled magnetically. Osteochondral defects were made in the center of rabbit and swine patellae, and magnetically labeled MSCs were injected into the knee joints either under the direction of an external magnetic force or with no magnetic force applied. In the rabbit model we evaluated the patellae macroscopically and histologically, and in the swine model we observed the patellae arthroscopically.

RESULTS

Accumulation of magnetically labeled MSCs to the osteochondral defect was shown macroscopically and histologically in the rabbit model and was shown by arthroscopic observation to be attached to the chondral defect in the swine model.

CONCLUSIONS

We showed the ability to deliver magnetically labeled MSCs to a desired place in the knee joint.

CLINICAL RELEVANCE

Our novel approach is applicable for human cartilage defects and may open a new era of repairing cartilage defects caused by osteoarthritis or trauma by use of a less invasive technique.