Microarray expression analysis of genes and pathways involved in growth plate cartilage injury responses and bony repair

The injured growth plate cartilage is often repaired by a bone bridge which causes bone growth deformities. Whilst previous studies have identified sequential inflammatory, fibrogenic, osteogenic and bone remodelling responses involved in the repair process, the molecular pathways which regulated these cellular events remain unknown. In a rat growth plate injury model, tissue from the injury site was collected across the time-course of bone bridge formation using laser capture microdissection and was subjected to Affymetrix microarray gene expression analysis. Real Time PCR and immunohistochemical analyses were used to confirm changes in levels of expression of some genes identified in microarray. Four major functional groupings of differentially expressed genes with known roles in skeletal development were identified across the time-course of bone bridge formation, including Wnt signalling (SFRP1, SFRP4, β-catenin, Csnk2a1, Tcf7, Lef1, Fzd1, Fzd2, Wisp1 and Cpz), BMP signalling (BMP-2, BMP-6, BMP-7, Chrd, Chrdl2 and Id1), osteoblast differentiation (BMP-2, BMP-6, Chrd, Hgn, Spp1, Axin2, β-catenin, Bglap2) and skeletal development (Chrd, Mmp9, BMP-1, BMP-6, Spp1, Fgfr1 and Traf6). These studies provide insight into the molecular pathways which act cooperatively to regulate bone formation following growth plate cartilage injury and highlight potential therapeutic targets to limit bone bridge formation.

Applications and limits of platelet-rich plasma in sports related injuries

Platelet-rich plasma (PRP) is a promising alternative approach based on the efficacy of autologous growth factors to accelerate tissue healing, allowing a fast recovery after muscles, ligaments, tendon or cartilage lesions. This literature review begin focusing on the role of platelets growth factors in these tissue healing and on the available preparation methods for PRP. Moreover we consider the in vitro and in vivo study on PRP, some of the most important therapeutic applications and limitations. Although several preclinical studies show promising results, clinical studies still show controversial results. Further studies are required to define the efficacy and to specify the way of using PRP in the orthopaedic practice.

Wound healing gene therapy: cartilage regeneration induced by vascular endothelial growth factor plasmid

AIMS

The identification of growth factors and cytokines with angiogenic activity has enabled new therapeutic treatments for a variety of diseases; this concept is called therapeutic angiogenesis. The vascular endothelial growth factor (VEGF) is the most critical regulator of vascular formation. In the present study, we were interested in the therapeutic angiogenesis effect using plasmid transfer of human complementary DNA VEGF(165) (phVEGF(165)) in experimental skin and cartilage trauma.

METHODS

Ten BALB/c mice were used for cartilage injury model. At 6 weeks of age, all mice were ear-punched, resulting in 2-mm-diameter puncture through the center of both pinnae. Each mouse got phVEGF(165) injection into the first ear and vector without insert or saline injection into the second one. The healing process was followed. The hollow diameter was measured on days 0, 14, and 42. Histological sections of experimental and control pinnae were taken from days 1, 3, 5, 7, 9, 11, 13, 15, 20, and 30 after experimental injury for hematoxylin and eosin and periodic acid Schiff staining and for human VEGF immunocytochemistry. The expression of human VEGF was also checked by real-time polymerase chain reaction in formalin-fixed, paraffin-embedded tissue sections.

KEY FINDINGS

In BALB/c mouse strain, a significant angiogenesis promotion and cartilage repair were observed after phVEGF(165) injection into the punched ear area.

SIGNIFICANCE

We suggest that administering phVEGF(165) leads to faster cartilage regeneration even if not only on the angiogenic basis.

Isolation and cultivation of mesenchymal stem cells from iliac crest bone marrow for further cartilage defect management

AIM

to validate isolation and cultivation methods of bone marrow mesenchymal stem cells (BM-MSCs) from iliac crest, and to compare biological characteristics of BM-MSCs from different age groups for preparation of autologous stem cell therapy in cartilage defect.

METHODS

patients undergoing spinal surgery were selected and grouped according to age. Iliac crest bone marrow from the patients was aspirated. BM-MSCs were isolated from the bone marrow and then cultivated. Their biological characteristics including morphological appearances and surface biomarkers were evaluated. Growth curves were observed. Sterility and Mycoplasma tests were also performed for quality assessment of BM-MSCs culture procedure.

RESULTS

in average, cultivated-BM-MSCs reached the number of 7.56-22.95 x 106 in 4-7 weeks period. BM-MSCs of all age groups showed the same quality of morphology, shape and surface biomarkers (CD105+, CD73+, CD34-, CD45-, CD14-, CD19-, HLA-DR-).

CONCLUSION

our procedures in isolating and cultivating of BM-MSCs have reached required amount for implantation into the cartilage lesion. In addition, the cultivated-BM-MSCs' biological characteristics were also in accordance with International Society of Cell Therapy (ISCT) MSCs criteria.

Techniques for cartilage repair in chondral and osteochondral defects of the knee

Many techniques are currently used in an attempt to regenerate cartilage surfaces in the presence of a chondral or osteochondral defect. Clinical results have been mixed and no single treatment has emerged as being superior. This article reviews the techniques previously and currently being used and evidence to support their use.

[Problems and complications of surgical techniques for treatment of full-thickness cartilage defects]

AIM

There has been great progress concerning the surgical treatment of full-thickness cartilage defects within recent years. Surgical techniques such as arthroscopic microfracturing (MF), autologous osteochondral transplantation (OCT) and autologous chondrocyte implantation (ACI) have been introduced and, by using these techniques, reliable and satisfying clinical results can be achieved. Nevertheless, there are also technique-related problems and characteristic complications of all surgical techniques in the field of cartilage repair. Knowledge of these complications is essential for every surgeon using these techniques. The aim of the present article is to give an overview concerning technique-associated and characteristic complications of the most common cartilage repair techniques including arthroscopic microfracturing, autologous osteochondral transplantation and autologous chondrocyte implantation (ACI).

METHODS

In order to identify relevant literature concerning complications following cartilage repair, medical databases including "medline", "ovid" and "web of science" were searched for the terms "autologous chondrocyte implantation", "autologous chondrocyte transplantation", "microfracture", "osteochondral transplantation", "cartilage repair", "cartilage defect" and "complications" in October 2009. The present publication represents a non-systematic review including publications which were considered relevant for describing charateristic complications and adverse events in surgical techniques used for cartilage repair.

RESULTS

Although the number of studies describing complications and adverse events following surgical cartilage repair studies is limited, for all techniques included in the present review (arthroscopic microfracturing, autologous osteochondral transplantation and autologous chondrocyte implantation) technique-associated and characteristic complications could be identified. While regenerative tissue following microfracturing seems to be limited in terms of durability, intralesional bone formation and elevation of the subchondral bone plate seem to be characteristic problems of this technique. Harvest morbidity, degeneration of the surrounding cartilage, necrosis of the transplanted cylinders and a lack of integration of the cartilage into the surrounding cartilage seem to be related to the transplantation of osteochondral cylinders (OATS/OCT), while hypertrophic regenerative cartilage, disturbed fusion into the adjacent cartilage, delamination and insufficient cartilage regeneration are associated with the autologous chondrocyte implantation (ACI).

CONCLUSION

The present paper identifies technique-associated complications for the most common surgical techniques used for cartilage repair. Even if the clinical relevance of the complications described in the current article has not been investigated to its fullest extent, the awareness of these characteristic complications is essential in order to avoid them whenever possible or to develop standardised treatment regimes for these problems. This needs to be addressed in further investigations.

MRI image overlay: Application to arthrography needle insertion

Magnetic Resonance Imaging (MRI) offers great potential for planning, guiding, monitoring and controlling interventions. MR arthrography (MRAr) is the imaging gold standard for assessing small ligament and fibrocartilage injury in joints. In contemporary practice, MRAr consists of two consecutive sessions: (1) an interventional session where a needle is driven to the joint space and MR contrast is injected under fluoroscopy or CT guidance; and (2) a diagnostic MRI imaging session to visualize the distribution of contrast inside the joint space and evaluate the condition of the joint. Our approach to MRAr is to eliminate the separate radiologically guided needle insertion and contrast injection procedure by performing those tasks on conventional high-field closed MRI scanners. We propose a 2D augmented reality image overlay device to guide needle insertion procedures. This approach makes diagnostic high-field magnets available for interventions without a complex and expensive engineering entourage. In preclinical trials, needle insertions have been performed in the joints of porcine and human cadavers using MR image overlay guidance; in all cases, insertions successfully reached the joint space on the first attempt.

Differential diagnosis in painful ischiopubic synchondrosis (IPS): a case report

Synchondroses are temporary joints that only exist during skeletal maturation. Bilateral widening of the ischiopubic synchondrosis (IPS) is a normal growth phenomenon, but when it is unilateral and painful it can become a diagnostic challenge. An eight-year-old child with an enlarged symptomatic unilateral synchondrosis is presented. Failure of conservative treatment and its pseudo-tumoral appearance led us to intervene surgically. Pathology revealed a stress fracture. Based on this clinical case, we made a revision of policy regarding pathology, diagnostic workup and treatment strategies for symptomatic synchondrosis.

N-acetylcysteine inhibits post-impact chondrocyte death in osteochondral explants

BACKGROUND

Chondrocyte death has been linked to injury-induced oxidative damage, suggesting that antioxidants could substantially improve viability. However, since reactive oxygen species play roles in normal physiology, there are concerns that antioxidants may have deleterious side effects. To address these issues, we studied the effects of N-acetylcysteine, a potent free radical scavenger, on chondrocyte viability and cartilage proteoglycan content in an in vitro cartilage injury model. We hypothesized that treatment with N-acetylcysteine soon after an impact injury would have significant chondrocyte-sparing effects and would prevent injury-induced proteoglycan losses.

METHODS

Bovine osteochondral explants were subjected to a single impact load with use of a drop-tower device. Chondrocyte viability was measured at multiple time points post-impact with use of fluorescent probes and confocal microscopy. Forty-eight hours after impact, the effects on viability of immediate post-impact treatment with N-acetylcysteine were compared with the effects of the caspase inhibitor N-CBZ-Val-Ala-Asp(O-Me) fluoromethyl ketone and those of the cell-membrane-stabilizing surfactant poloxamer 188. The effect of N-acetylcysteine on proteoglycan content was determined at seven and fourteen days post-impact.

RESULTS

Chondrocyte viability declined sharply within an hour and reached a steady state within six to twelve hours after impact. Immediate treatment with N-acetylcysteine doubled the number of viable chondrocytes assayed forty-eight hours after impact, and this effect was significantly greater than that of N-CBZ-Val-Ala-Asp(O-Me) fluoromethyl ketone. Even when N-acetylcysteine treatment was delayed for up to four hours after injury, it still had significant positive effects on cell viability at forty-eight hours. Moreover, N-acetylcysteine treatment significantly improved proteoglycan content at the impact sites at both seven and fourteen days after injury.

CONCLUSIONS

Treatment with N-acetylcysteine soon after a blunt impact injury can reduce chondrocyte death and proteoglycan loss measured seven to fourteen days after injury.

Co-culture of mechanically injured cartilage with joint capsule tissue alters chondrocyte expression patterns and increases ADAMTS5 production

We studied changes in chondrocyte gene expression, aggrecan degradation, and aggrecanase production and activity in normal and mechanically injured cartilage co-cultured with joint capsule tissue. Chondrocyte expression of 21 genes was measured at 1, 2, 4, 6, 12, and 24h after treatment; clustering analysis enabled identification of co-expression profiles. Aggrecan fragments retained in cartilage and released to medium and loss of cartilage sGAG were quantified. Increased expression of MMP-13 and ADAMTS4 clustered with effects of co-culture, while increased expression of ADAMTS5, MMP-3, TGF-beta, c-fos, c-jun clustered with cartilage injury. ADAMTS5 protein within cartilage (immunohistochemistry) increased following injury and with co-culture. Cartilage sGAG decreased over 16-days, most severely following injury plus co-culture. Cartilage aggrecan was cleaved at aggrecanase sites in the interglobular and C-terminal domains, resulting in loss of the G3 domain, especially after injury plus co-culture. Together, these results support the hypothesis that interactions between injured cartilage and other joint tissues are important in matrix catabolism after joint injury.

Microfracture technique in combination with intraarticular hyaluronic acid injection in articular cartilage defect regeneration in rabbit model

Although articular hyaline cartilage typically has low potential for regeneration, numerous methods and techniques have been proposed to induce the reparation process. In our work, we used microfracture techniques in combination with intraarticular application of hyaluronic acid in rabbit knee articular cartilage defect. In comparison with the control group, after 6 and 10 weeks we observed a higher potential of healing in the experimental group, with thicker and more organized repair tissue filling the defect. In conclusion, a combination of the microfracture technique and application of hyaluronic acid might be potentially beneficial in inducing articular cartilage defect reparation.

Autologous chondrocytes implantation for traumatic cartilage defects of the knee

OBJECTIVE

To evaluate the results of autologous chondrocytes implantation in the patients with large traumatic cartilage defects of the knee.

MATERIAL AND METHOD

Five patients (six knees) with grade 3-4 according to International Cartilage Repair Society Classification System were performed ACI between May 2006 and April 2007. The two-stage procedure was performed. First, the cartilage was arthroscopic harvested. The chondrocytes were isolated in the laboratory. Second, the chondrocytes were re-implanted into the defects. The patients were clinically evaluated preoperatively and postoperatively with Knee and Osteoarthritis Outcome Score (KOOS), magnetic resonance imaging, and arthroscopic assessment. The mean duration of follow-up was 19.8 +/- 4.6 months.

RESULTS

There was no postoperative complication. The clinical evaluation with Knee and Osteoarthritis Outcome Score (KOOS) showed significant improvement. The MRI showed the filling of regenerative cartilage tissue formation at the defects. The arthroscopic assessment showed the good defect fill, stiffness, and incorporation to the adjacent cartilage.

CONCLUSION

The autologous chondrocytes implantation showed the potential for the treatment of large cartilage defects. The excellent results allowed patients to return to normal activity level.

[Therapeutic algorithm for traumatic cartilage injuries]

Reports regarding sport injuries frequently pertain to the knee. Although ligament and meniscus damage are the most common, cartilage injuries are of great interest. Even with the great variety of treatment modalities available, the healing of these cartilage injuries remains problematic. Due to the complex structure of hyaline cartilage joint surface, repair has proven to be very difficult. The conservative treatment options range from orthotic devices and physical therapy to systemic and intraarticular medication. In case of failure, a wide variety of surgical interventions exist. Among these surgical treatment forms, one must differentiate between the repair and the reconstruction of hyaline joint surfaces. In the latter group only the osteochondral autologous transplantation procedures allow for the reconstruction of a cartilaginous lesion with hyaline cartilage as part of a single procedure. This paper will provide an overview of most common therapeutic approaches to cartilage injuries available today. Even with the ongoing discussions with regard to cartilage healing, the basics such as the ligamentous stability of the affected joint, the mechanical axis of the extremity and good neuromuscular control must always be part of the algorithm.

A complication of soft tissue graft tibial fixation with the IntraFix device

BACKGROUND

One potential complication of interference devices to fix anterior cruciate ligament (ACL) grafts is divergence between the implant and the graft-tunnel. Tunnel-screw divergence >15-30 degrees significantly reduces graft-tunnel fixation and may compromise the stability of the knee.

CASE REPORT

A complication of the IntraFix device is presented. A 43-year-old male sustained a primary ACL reconstruction. The autologous hamstring graft was fixed in the tibia with the IntraFix device. The procedure went without apparent incidents or complications. During postoperative follow-up he developed pain and crepitus over the anteromedial aspect of the operated knee. A flexion contracture slowly developed up to 10 degrees and did not improve with aggressive physiotherapy. At eight postoperative weeks, second-look arthroscopy was performed. The intraoperative findings were a healthy-looking ACL graft and a grade III chondral injury in the medial femoral condyle (MFC) caused by the tip of the IntraFix device, which protruded through the medial tibial plateau. During flexion-extension motion of the knee, the tip eroded the chondral surface of the MFC. This was treated with mechanical and thermal chondroplasty and the tip of the IntraFix device was burred flat to match the surface of the medial tibial plateau. The patient's symptoms improved.

CONCLUSIONS

Divergence of the interference screws in the femur is not uncommon, but on the tibia it is rare. Although this technical error did not affect stability, it did produce intrarticular injury. Strict adherence to the surgical technique is recommended and several hints on how to avoid complications with this implant are suggested.

[Magnetic resonance assessment the effect of manipulation on knee cartilaginous recovery of osteoarthritis]

OBJECTIVE

To observe and assess the effect of manipulation on knee cartilaginous recovery with knee osteoarthritis (OA) by using magnetic resonance (MR).

METHODS

Fifty cases which were suffering from knee OA involved this retrospective study. They were matched-pairs into 2 groups according to their gender, age and severity. Treated with manipulation once a week in one year for manipulation group patients, compared with those orally use with 500 mg glucosamine sulfate (GS) three times per day. Knee cartilage MR were performed before treatment and on 3, 6, 12 months after treatment, the maximum defect diameter and volume of knee cartilage were assessed with Noyes Score.

RESULT

Both Noyes Score declined in the two groups. But Noyes Score of the manipulation group significantly decreased 6 months after treatment, the same tendency was observed just 12 months after treatment in another group. The maximum defect diameter of knee cartilage began to diminish at 3 months after treatment in the manipulation group, grew significantly at 6 and 12 months after treatment compared with before treatment. In the GS group, there was no significantly deference in the maximum defect diameter of knee cartilage between after and before treatment. The volume of knee cartilage in manipulation group was greater than the GS group at 3, 6, 12 months after treatment and significantly increased at 6 months after treatment and grew 58 percent 12 months after treatment. The volume of knee cartilage in GS group had no significantly change, though had a tendency to increase.

CONCLUSION

Manipulation is effective to treatment of knee osteoarthritis by decreasing the maximum defect diameter and increasing the volume of knee cartilage.

MRI of cartilage and subchondral bone injury. A pictorial review

In this article, we present an overview of various cartilage and subchondral bone abnormalities seen on MRI. Injury of bone is often associated with cartilage damage and vice versa. A number of common conditions affecting joints typically show certain combinations of chondral and subchondral changes.

Mechanical properties of hyaline and repair cartilage studied by nanoindentation

Articular cartilage is a highly organized tissue that is well adapted to the functional demands in joints but difficult to replicate via tissue engineering or regeneration. Its viscoelastic properties allow cartilage to adapt to both slow and rapid mechanical loading. Several cartilage repair strategies that aim to restore tissue and protect it from further degeneration have been introduced. The key to their success is the quality of the newly formed tissue. In this study, periosteal cells loaded on a scaffold were used to repair large partial-thickness cartilage defects in the knee joint of miniature pigs. The repair cartilage was analyzed 26 weeks after surgery and compared both morphologically and mechanically with healthy hyaline cartilage. Contact stiffness, reduced modulus and hardness as key mechanical properties were examined in vitro by nanoindentation in phosphate-buffered saline at room temperature. In addition, the influence of tissue fixation with paraformaldehyde on the biomechanical properties was investigated. Although the repair process resulted in the formation of a stable fibrocartilaginous tissue, its contact stiffness was lower than that of hyaline cartilage by a factor of 10. Fixation with paraformaldehyde significantly increased the stiffness of cartilaginous tissue by one order of magnitude, and therefore, should not be used when studying biomechanical properties of cartilage. Our study suggests a sensitive method for measuring the contact stiffness of articular cartilage and demonstrates the importance of mechanical analysis for proper evaluation of the success of cartilage repair strategies.

Analysis of Nd:YAG laser-mediated thermal damage in rabbit nasal septal cartilage

BACKGROUND AND OBJECTIVES

Laser cartilage reshaping (LCR) involves the use of photo-thermal heating to reshape cartilage. Its clinical relevance depends on the ability to minimize thermal injury in irradiated regions. The present study seeks to understand the safety of LCR by determining shape change and resultant tissue viability as a function of laser dosimetry.

STUDY DESIGN/MATERIALS AND METHODS

Rabbit nasal septal cartilage were irradiated using a Nd:YAG laser (lambda = 1.32 microm, 5.4 mm spot diameter) with different exposure times of 4, 6, 8, 10, 12, and 16 seconds and powers of 4, 6, and 8 W. Temperature on the cartilage surface in the laser-irradiated region was collected using infrared thermography, this data was then used to predict tissue damage via a rate process model. A Live/Dead viability assay combined with fluorescent confocal microscopy was used to measure the amount of thermal damage generated in the irradiated specimens.

RESULTS

Considerable thermal injury occurred at and below the laser-reshaping parameters that produced clinically relevant shape change using the present Nd:YAG laser. Confocal microscopy identified dead cells spanning the entire cross-sectional thickness of the cartilage specimen (about 500 microm thick) at laser power density and exposure times above 4 W and 6 seconds; damage increased with time and irradiance. The damage predictions made by the rate process model compared favorably with measured data.

CONCLUSIONS

These results demonstrate that significant thermal damage is concurrent with clinically relevant shape change. This contradicts previous notions that there is a privileged laser dosimetry parameter where clinically relevant shape change and tissue viability coexist.

Healing full-thickness cartilage defects using adipose-derived stem cells

The purpose of this study was to evaluate the use of adipose-derived stem cells (ADSCs) as a source for full-thickness cartilage repair in an animal model. Autologous ADSCs were isolated and induced with growth medium and placed in a fibrin glue scaffold and into 3-mm x 4-mm full-thickness chondral defects in rabbits with negative controls. Specimens were evaluated for early healing using immunostaining, Western blotting, reverse transcriptase polymerase chain reaction, transfection with the Lac Z gene, and quantitative assessment. Twelve of 12 (100%) articular surface defects containing tissue-engineered stem cell constructs healed with hyaline-like cartilage, versus 1 of 12 (8%) in the control group (p < .001). There was complete healing to subchondral bone in 12 of 12 experimental defects (100%), and 10 of 12 (83%) had seamless annealing to the native cartilage. Aggrecan, superficial zone protein, collagen type II messenger ribonucleic acid, and Lac-Z gene products were identified in 12 of 12 experimental specimens, which exhibited a collagen type II:I protein ratio similar to that of normal rabbit cartilage. Quantitative histologic analysis revealed an average score of 18.2 of 21 in the experimental group, compared with 10.0 in the controls (p = .001). Induced ADSCs supported in a fibrin glue matrix are a promising cell source for cartilage tissue engineering.