Equine articular chondrocytes on MACT scaffolds for cartilage defect treatment

Treatment of cartilage defects poses challenging problems in human and veterinary medicine, especially in horses. This study examines the suitability of applying scaffold materials similar to those used for human cartilage regeneration on equine chondrocytes. Chondrocytes gained from biopsies of the talocrural joint of three horses were propagated in 2D culture and grown on two different scaffold materials, hyaluronan (HYAFF®) and collagen (BioGide®), and evaluated by light and electron microscopy. The equine chondrocytes developed well in both types of materials. They were vital and physiologically highly active. On the surface of the scaffolds, they formed cell multilayers. Inside the hyaluronan web, the chondrocytes were regularly distributed and spanned the large scaffold fibre distances by producing their own matrix sheath. Half-circle-like depressions occasionally found in the cell membrane were probably related to movement on the flexible matrix sheath. Inside the dense collagen scaffold, only single cells were found. They passed through the scaffold strands by cell shape adaptation. This study showed that the examined scaffold materials can be used for equine chondrocyte cultivation. Chondrocytes tend to form multilayers on the surface of both, very dense and very porous scaffolds, and have strategies to span between and move in large gaps.

Detection of urolithiasis using low-dose CT--a noise simulation study

How does an acquisition at reduced doses using automatic tube current modulation techniques compare to the normal standard dose CT? Does it affect the sensitivity for detection of calcifications? CT raw data of 54 patients with suspected urolithiasis acquired with automatic tube current modulation techniques were used for image noise simulations with 100%, 50% and 25% dose simulated. Data were analyzed by independent readers with regard to the presence of urolithiasis, stone location, size, density and differential diagnoses. The mean effective dose per standard examination/50%/25% simulation was 7.3 mSv/3.8 mSv/1.9 mSv. Sensitivities/specificities for detection of urolithiasis were calculated for all dose simulations and resulted in 0.94/0.98 in the 50% dose level group and 0.82/0.97 in the 25% dose level group. Low-dose CT with tube current modulation can be used as a standard procedure for the evaluation of patients with suspected acute renal colic.

[Therapeutic options in the treatment of cartilage defects. Techniques and indications]

BACKGROUND

Cartilage is composed of chondrocytes embedded within an extracellular matrix of collagens, proteoglycans, and noncollagenous proteins. Together, these structures maintain the unique mechanical properties and manifest its striking inability to heal even the most minor injury.

METHODS

This review presents the principles of cartilage structure and the biological background of cartilage repair and gives information about the surgical techniques for treating cartilage defects.

RESULTS

The response of cartilage to injuries differs from that of other tissues because of its avascularity, the immobility of chondrocytes and the limited ability of mature chondrocytes to proliferate and alter their synthetic patterns. Surgical therapeutic efforts in treating cartilage defects have focused on bringing new cells and tissues capable of chondrogenesis into the lesions and facilitating the access to the vascular system.

CONCLUSION

The right indication and the treatment of joint instability and axis deformation are essential for the successful use of cartilage repair procedures.

Autologe Chondrozytentransplantation zur Behandlung von Knorpeldefekten des Kniegelenks

BACKGROUND

Currently the use of autologous chondrocytes as a cartilage-repair procedure for the repair of injured articular cartilage of the knee joint, is recommended.

METHODS

This review presents the technique of autologous chondrocyte transplantation (ACT) and their modifications as matrix-associated autologous chondrocyte transplantation (MACT). Beside the surgical procedure the experimental and clinical results are discussed. Furthermore the major complications and the indication guidelines are presented.

RESULTS

Articular cartilage in adults has a poor ability to self-repair after a substantial injury. Surgical therapeutic efforts in treating cartilage defects have focused on bringing new cells capable of chondrogenesis into the lesions. With ACT good to excellent clinical results are seen in isolated posttraumatic lesions of the knee joint in the younger patient with the formation of hyaline-like repair tissue. The major complications are periosteal hypertrophy, delamination of the transplant, arthrofibrosis and transplant failure. The current limitations include osteoarthritic defects and higher patient age.

CONCLUSION

With the right indication and operative technique ACT is an effective and save option for the treatment of large full thickness cartilage defect of the knee joint.