Proposal for a new histological scoring system for cartilage repair

OBJECTIVE: This study aimed to develop a new histological scoring system for use in a partial-thickness cartilage repair animal model. Although previous papers have investigated the regeneration of articular cartilage, the good results achieved in small animals have not been replicated in large animal models or humans, possibly because of the frequent use of models with perforation of the subchondral bone plates. Partial-thickness lesions spare the subchondral bone, and this pattern is the most frequent in humans; therefore, new therapies should be tested using this model. However, no specific histological score exists to evaluate partial-thickness model results. METHODS: Histological sections from 30 ovine knees were reviewed to develop a new scoring system. The sections were subjected to H&E, Safranin O, and Masson's trichrome staining. RESULTS: This paper describes a new scoring tool that is divided into sections in detail: repair of tissue inside the lesion, cartilage around the lesion and degenerative changes at the base of the lesion. Scores range from 0 to 21; a higher score indicates better cartilage repair. DISCUSSION: Unlike existing tools, this new scale does not assign points for the positioning of a tidemark; we propose evaluation of the degenerative changes to the subchondral bone and calcified cartilage layer. It is necessary to remove the whole joint to access and study the evolution of the lesion as well as the surrounding tissue. CONCLUSION: This article emphasizes the importance of a partial-thickness animal model of cartilage repair and presents a new histological scoring system.

Using mesenchymal stem cells as a therapy for bone regeneration and repairing

Bone is a unique tissue which could regenerate completely after injury rather than heal itself with a scar. Compared with other tissues the difference is that, during bone repairing and regeneration, after the inflammatory phase the mesenchymal stem cells (MSCs) are recruited to the injury site and differentiate into either chondroblasts or osteoblasts precursors, leading to bone repairing and regeneration. Besides these two precursors, the MSCs can also differentiate into adipocyte precursors, skeletal muscle precursors and some other mesodermal cells. With this multiline-age potentiality, the MSCs are probably used to cure bone injury and other woundings in the near future. Here we will introduce the recent developments in understanding the mechanism of MSCs action in bone regeneration and repairing.

Nestin-positive stem cells participate in chondrocyte renewal in healthy adult lung cartilage / Células troncales nestin-positivas participan en la renovación de condrocitos en el cartílago pulmonar del adulto sano

It is considered that healthy adult cartilage has little or no capacity for renewal, and that chondrocytes maintain a stable resting phenotype and resist proliferation and differentiation throughout life. Recently we found that cell turnover in lung cartilage is possible and that nestin-positive cells may have a role in it. In this paper, we report additional findings about chondrocyte renewal in lung cartilage. Lung specimens from CD1 mice at the age of 2, 6, 12, 18 or 24 months were fixed in 10% neutral-buffered formalin and paraffin-embedded. Nestin expression was examined by an immunohistochemical peroxidase-based method. We found nestin-positive cells inside of cartilage islets and cells in division very close from them. Our findings indicate that there exist nestin-positive mesenchymal stem cells in the adult that are able to differentiate into lung chondrocytes, perhaps to maintain homeostasis or repair damaged tissue. These findings may improve our knowledge about the cartilage biology and could provide new cell candidates for cartilage tissue engineering.

Se considera que el cartílago adulto sano tiene poca o ninguna capacidad para renovarse, y que sus condrocitos permanecen en un estado de reposo estable, careciendo de las propiedades de proliferación y diferenciación. Recientemente encontramos que el recambio celular en el cartílago pulmonar es posible y que células troncales positivas para nestin pudieran tener algún papel en el mismo. En este artículo, reportamos nuevos hallazgos acerca de la renovación de condrocitos en el cartílago pulmonar. Pulmones de ratones CD1 de 2, 6, 12, 18 o 24 meses de edad se fijaron en formalina amortiguada al 10% y se incluyeron en parafina. Se analizó la expresión de nestin utilizando un método inmunohistoquímico basado en un sistema de detección con peroxidasa. Encontramos células positivas para nestin en el interior de los islotes de cartílago y células en división muy cercanas a ellas. Estos hallazgos indican que existen células madre mesenquimales positivas para nestin en el adulto con capacidad para diferenciarse en condrocitos pulmonares, probablemente para mantener la homeostasis tisular o reparar daños en el tejido. Asimismo, estos hallazgos pueden aumentar nuestra comprensión acerca de las propiedades biológicas del cartílago y podrían proporcionar nuevos candidatos para la ingeniería celular en la terapia regenerativa en enfermedades de las articulaciones.

Reparação de defeitos osteocondrais de cães com implante de cultura de condrócitos homólogos e membrana biossintética de celulose: avaliação clínica, ultrassonográfica e macroscópica / The repair of osteochondral defects in dogs with homologous articular chondrocytes and biosynthetic cellulose membrane: clinical, ultrasound and macroscopic evaluation

Avaliou-se o implante de condrócitos homólogos em lesões osteocondrais, utilizando a membrana biossintética à base de celulose (MBC) como revestimento. Dez cães adultos e clinicamente sadios foram submetidos à artrotomia das articulações fêmoro-tíbio-patelares. Defeitos de quatro milímetros de diâmetro por quatro milímetros de profundidade foram induzidos na tróclea femoral de ambos os membros. A MBC foi aplicada na base e superfície das lesões. Os defeitos do membro direito foram preenchidos com condrócitos homólogos cultivados e formaram o grupo tratado (GT); e os defeitos do membro esquerdo, sem implante celular, formaram o grupo controle (GC). Os animais foram avaliados clínica e ultrassonograficamente aos 30 e 60 dias. A evolução pós-operatória dos cães foi analisada com especial interesse nos processos de reparação da lesão, por meio de macroscopia. Não houve diferença clínica e ultrassonográfica entre os grupos. Entretanto, à macroscopia, ocorreu maior prevalência de formação de tecido cicatricial esbranquiçado no GT. O tecido neoformado apresentou melhor qualidade associado ao implante homólogo de condrócitos, mas não promoveu reparação por cartilagem hialina.

The aim of the study was to evaluate the repair of deep cartilaginous defects made in the femoral trochlear sulcus of dogs, using the cellulose biosynthetic membrane (CBM) as coating. Ten healthy adult dogs without locomotor disorders were used. All animals were submitted to arthrotomy of stifle joints and defects with four millimeters diameter x four millimeters deep were done in the femoral trochlear sulcus of both limbs. CBM was applied in the lesion's base and surface of all limbs. In the treated group (TG), the defects of the right limb were filled with cultivated homologous chondrocytes, and in control group (CG), the defects of the left limb were filled without cellular implant. The animals were evaluated by physical examination and ultrasound at 30 and 60 days. The postoperative follow up of the dogs was done by macroscopy with special interest in the healing process of the osteochondral defect. No clinical and ultrasonographic differences were observed in both groups. In the macroscopic evaluation higher prevalence of whitish scar tissue formation was noted in TG, but without statistical difference. The neoformed tissue showed slightly higher quality in TG, but without promoting repair by the hyaline cartilage.

Aspectos moleculares dos esteroides sexuais sobre a cartilagem e os ossos / Molecular features of sexual steroids on cartilage and bone

No Brasil, o crescimento dos casos registrados de doenças degenerativas das cartilagens articulares por ano é de 20%, o que representa, anualmente, que mais de 200 mil brasileiros desenvolvem doenças degenerativas das articulações e, com repercussões negativas sobre a massa óssea. Este trabalho mostra evidências que a produção hormonal de esteroides sexuais (estrogênios, progestagênios e androgênios) têm influência na qualidade da cartilagem, bem como na massa óssea. Portanto, o objetivo dessa revisão foi o de analisar os dados da literatura sobre a ação molecular e gênica dos esteroides sexuais na fisiologia da cartilagem hialina e do osso, bem como a interferência da osteoartrite na qualidade dessas estruturas.

In Brazil, the increase in the reported cases of degenerative diseases of articular cartilage is 20% per year, meaning that 200,000 Brazilians develop degenerative joint diseases every year, which have a negative impact on bone mass. This study shows evidence that hormone production of sexual steroids (estrogens, progestogens, and androgens) have an influence on cartilage quality, as well as on bone mass. Therefore, this review aimed to analyze literature data on the molecular and genic action of sexual steroids on hyaline cartilage and bone physiology, as well as osteoarthritis interference on the quality of these structures.

Effect of low-power helium-neon laser irradiation on 13-week immobilized articular cartilage of rabbits.

Influence of low-power (632.8 nm, Helium-Neon, 13 J/cm2, three times a week) laser on 13-week immobilized articular cartilage was examined with rabbits knee model. Number of chondrocytes and depth of articular cartilage of experimental group were significantly higher than those of sham irradiated group. Surface morphology of sham-irradiated group had rough prominences, fibrillation and lacunae but surface morphology of experimental group had more similarities to control group than to sham irradiated group. There were marked differences between ultrastructure features of control group and experimental group in comparison with sham irradiated group. Low-power Helium-Neon laser irradiation on 13-week immobilized knee joints of rabbits neutrilized adverse effects of immobilization on articular cartilage.