Fate of a chimeric joint construct in an ectopic site in SCID mice.

This study examines the use of a devitalized biological knee as a scaffold for repopulation with chondrocytes and tests the hypothesis that the devitalized scaffold would become repopulated with the foreign chondrocytes when placed in a suitable environment. Chimeric knee constructs were engineered in vitro and their ectopic in vivo fate was examined in SCID mice. The constructs were made by applying porous collagen sponges that contained viable bovine articular chondrocytes to shaved articular surfaces of devitalized embryonic chick knees. The chimeric joints were cultured for 1 week and were subsequently transplanted into dorsal subcutaneous pouches of 5-week-old mice. Specimens were prepared for histological analysis at 1, 3, 6, or 8 weeks after transplantation. Controls included empty collagen sponges, collagen sponges seeded with viable bovine chondrocytes, and devitalized chick knees without collagen sponge inserts. One week after in vitro incubation of the constructs, the porous collagen sponges with viable bovine chondrocytes were adherent to the shaved articular surfaces of the devitalized chick joints. There was abundant metachromatic neomatrix around the chondrocytes in the collagen sponges. During maintenance of the constructs in vivo, the chimeric joints exhibited dramatic changes. Bovine chondrocytes proliferated in the collagen sponges and formed abundant new matrix. Bovine chondrocytes migrated into preexisting chick cartilage canals at 1 week. Subsequently, bovine chondrocytes invaded the matrix of the devitalized chick knees. Bovine neocartilage obliterated the interface between the collagen sponge and the devitalized chick cartilage. With time in vivo, the bovine neocartilage expanded and replaced the chick matrix. The devitalized cartilage appears to provide a framework for supporting chondrogenesis in a chimeric joint.

Cell-based therapy for meniscal repair: a large animal study.

BACKGROUND: The avascular portion of the meniscus cartilage in the knee does not have the ability to repair spontaneously. HYPOTHESIS: Cell-based therapy is able to repair a lesion in the swine meniscus. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen Yorkshire pigs were divided into four groups. A longitudinal tear was produced in the avascular portion of the left medial meniscus of 4 pigs. Autologous chondrocytes were seeded onto devitalized allogenic meniscal slices and were secured inside the lesion with two sutures. Identical incisions were created in 12 other pigs, which were used as three separate control groups: 4 animals treated with an unseeded scaffold, 4 were simply sutured, and 4 were left untreated. Meniscal samples were collected after 9 weeks, and the samples were analyzed grossly, histologically, and histomorphometrically. RESULTS: Gross results showed bonding of the lesion margins in the specimens of the experimental group, whereas no repair was noted in any of the control group specimens. Histological and histomorphometrical analysis showed multiple areas of healing in the specimens of the experimental group. CONCLUSIONS: This study demonstrated the ability of seeded chondrocytes to heal a meniscal tear. CLINICAL RELEVANCE: Cell-based therapy could be a potential tool for avascular meniscus repair.

Heterotopic ossification around the elbow following burns in children: results after excision.

BACKGROUND: Major burn injuries close to joints alter the function of the musculoskeletal system through tissue loss and limitation of joint motion. In children with involvement of the hand, wrist, and forearm, restriction of elbow motion secondary to heterotopic ossification following a burn injury severely limits the function of the upper extremity. The purpose of this study was to review elbow function following excision of heterotopic ossification around the elbow in children. METHODS: Eight children (ten elbows) from a population of 3245 consecutive patients who were admitted to our pediatric burn center were found to have severe heterotopic ossification of the elbow, leading to an inability to reach the mouth for feeding and the head and the perineum for self-care. Excision of the heterotopic ossification was undertaken if the patient had this limitation of function and if movement was restricted to a total arc of motion of <50 degrees. Pain was not an indication for the operation. The procedure was performed at an average of 17.3 months following the injury. RESULTS: Seven children (nine elbows) were available for follow-up at an average of fifty-six months after surgery. All nine elbows had an improved arc of motion (an average increase of 57 degrees ). Following excision, heterotopic ossification did not recur. All children were able to reach the face and the perineum following the operation. CONCLUSIONS: Excision of heterotopic ossification around the elbow following a burn injury in children can improve the arc of motion and improve the function of the extremity. A relatively simple operative and postoperative regimen can achieve satisfactory results.

Terapia celular en lesiones meniscales: un estudio en grandes animales. Segunda parte / Cell-based therapy for meniscal lesions: a study on large animals

El presente estudio analiza la potencialidad de una terapia celular para emplear en la reparacion de la zona avascular del menisco, en un modelo experimental de grandes animales. Fueron sembrados condrocitos articulares, aislados por digestion enzimatica de fragmentos de cartilago extraidos de cerdos Yorkshire, en porciones de cartilago meniscal como soporte. Se practicaron lesiones meniscales en asa de balde en 12 animales y sucesivamente se repararon mediante la interposicion y sutura del soporte sembrado con condrocitos autologos (grupo A: 3 animales). Se prepararon otros 3 grupos de control. En el grupo B, las lesiones fueron tratadas mediante la interposicion del soporte privado de celulas; en el grupo C, las lesiones fueron tratadas con sutura simple; mientras que las lesiones en el grupo D fueron dejadas sin tratamiento. Los animales fueron sacrificados luego de las 9 semanas y los meniscos se analizaron macroscopica e histologicamente. Los resultados demostraron una buena integracion entre el soporte sembrado con condrocitos y los margenes de las lesiones meniscales, que resultaron reparadas en numerosas areas, en los animales del grupo experimental A; mientras que ningun grado de reparacion pudo evidenciarse en ninguna de las muestras de los grupos control

Terapia celular en lesiones meniscales: un estudio en grandes animales. Segunda parte / Cell-based therapy for meniscal lesions: a study on large animals

El presente estudio analiza la potencialidad de una terapia celular para emplear en la reparacion de la zona avascular del menisco, en un modelo experimental de grandes animales. Fueron sembrados condrocitos articulares, aislados por digestion enzimatica de fragmentos de cartilago extraidos de cerdos Yorkshire, en porciones de cartilago meniscal como soporte. Se practicaron lesiones meniscales en asa de balde en 12 animales y sucesivamente se repararon mediante la interposicion y sutura del soporte sembrado con condrocitos autologos (grupo A: 3 animales). Se prepararon otros 3 grupos de control. En el grupo B, las lesiones fueron tratadas mediante la interposicion del soporte privado de celulas; en el grupo C, las lesiones fueron tratadas con sutura simple; mientras que las lesiones en el grupo D fueron dejadas sin tratamiento. Los animales fueron sacrificados luego de las 9 semanas y los meniscos se analizaron macroscopica e histologicamente. Los resultados demostraron una buena integracion entre el soporte sembrado con condrocitos y los margenes de las lesiones meniscales, que resultaron reparadas en numerosas areas, en los animales del grupo experimental A; mientras que ningun grado de reparacion pudo evidenciarse en ninguna de las muestras de los grupos control

Capacidad adhesivo-reparativa de condrocitos articulares aislados y trasplantados in vivo / Adhesive-reparative capacity of isolated and transplanted in vivo joint chondrocytes

La reparacion de los defectos condrales mediante el implante de condrocitos autologos presupone la sintesis por los condrocitos de matriz cartilaginosa con capacidad de adherirse a la superficie de la lesion. En este estudio, se evaluo la capacidad adhesivo-reparativa de condrocitos articulares aislados enzimaticamente, cultivados in vitro sobre matriz cartilaginosa desvitalizada y trasplantados in vivo en bolsillos subcutaneos de ratones atimicos. Se utilizaron 50 ratones atimicos, cada uno portador de dos muestras experimentales y dos de control, subdivididos en 5 tiempos experimentales, que correspondian 7, 14, 21, 28 y 42 dias desde el implante. El analisis de adhesividad en las muestras experimentales mostro valores siempre crecientes con el transcurso del tiempo hasta alcanzar un valor maximo entre los dias 28 y 42; mientras que las muestras de control registraron valores nulos durante todo el estudio. El analisis histologico de los preparados mostro que el adhesivo biologico en las muestras experimentales estaba constituido por cartilago neoformado capaz de promover la adhesion-reparacion de la matriz desvitalizada. Los resultados de este estudio demostraron que los condrocitos aislados y cultivados sobre matriz alogenica desvitalizada se encuentran en condiciones de producir in vivo neotejido cartilaginoso, con una propiedad adhesiva tal que permite la adhesion reciproca en la matriz de soporte

Capacidad adhesivo-reparativa de condrocitos articulares aislados y trasplantados in vivo / Adhesive-reparative capacity of isolated and transplanted in vivo joint chondrocytes

La reparacion de los defectos condrales mediante el implante de condrocitos autologos presupone la sintesis por los condrocitos de matriz cartilaginosa con capacidad de adherirse a la superficie de la lesion. En este estudio, se evaluo la capacidad adhesivo-reparativa de condrocitos articulares aislados enzimaticamente, cultivados in vitro sobre matriz cartilaginosa desvitalizada y trasplantados in vivo en bolsillos subcutaneos de ratones atimicos. Se utilizaron 50 ratones atimicos, cada uno portador de dos muestras experimentales y dos de control, subdivididos en 5 tiempos experimentales, que correspondian 7, 14, 21, 28 y 42 dias desde el implante. El analisis de adhesividad en las muestras experimentales mostro valores siempre crecientes con el transcurso del tiempo hasta alcanzar un valor maximo entre los dias 28 y 42; mientras que las muestras de control registraron valores nulos durante todo el estudio. El analisis histologico de los preparados mostro que el adhesivo biologico en las muestras experimentales estaba constituido por cartilago neoformado capaz de promover la adhesion-reparacion de la matriz desvitalizada. Los resultados de este estudio demostraron que los condrocitos aislados y cultivados sobre matriz alogenica desvitalizada se encuentran en condiciones de producir in vivo neotejido cartilaginoso, con una propiedad adhesiva tal que permite la adhesion reciproca en la matriz de soporte