In vitro cultivation of canine multipotent mesenchymal stromal cells on collagen membranes treated with hyaluronic acid for cell therapy and tissue regeneration

Support structures for dermal regeneration are composed of biodegradable and bioresorbable polymers, animal skin or tendons, or are bacteria products. The use of such materials is controversial due to their low efficiency. An important area within tissue engineering is the application of multipotent mesenchymal stromal cells (MSCs) to reparative surgery. The combined use of biodegradable membranes with stem cell therapy may lead to promising results for patients undergoing unsuccessful conventional treatments. Thus, the aim of this study was to test the efficacy of using membranes composed of anionic collagen with or without the addition of hyaluronic acid (HA) as a substrate for adhesion and in vitro differentiation of bone marrow-derived canine MSCs. The benefit of basic fibroblast growth factor (bFGF) on the differentiation of cells in culture was also tested. MSCs were collected from dog bone marrow, isolated and grown on collagen scaffolds with or without HA. Cell viability, proliferation rate, and cellular toxicity were analyzed after 7 days. The cultured cells showed uniform growth and morphological characteristics of undifferentiated MSCs, which demonstrated that MSCs successfully adapted to the culture conditions established by collagen scaffolds with or without HA. This demonstrates that such scaffolds are promising for applications to tissue regeneration. bFGF significantly increased the proliferative rate of MSCs by 63% when compared to groups without the addition of the growth factor. However, the addition of bFGF becomes limiting, since it has an inhibitory effect at high concentrations in culture medium.

In vitro cultivation of canine multipotent mesenchymal stromal cells on collagen membranes treated with hyaluronic acid for cell therapy and tissue regeneration.

Support structures for dermal regeneration are composed of biodegradable and bioresorbable polymers, animal skin or tendons, or are bacteria products. The use of such materials is controversial due to their low efficiency. An important area within tissue engineering is the application of multipotent mesenchymal stromal cells (MSCs) to reparative surgery. The combined use of biodegradable membranes with stem cell therapy may lead to promising results for patients undergoing unsuccessful conventional treatments. Thus, the aim of this study was to test the efficacy of using membranes composed of anionic collagen with or without the addition of hyaluronic acid (HA) as a substrate for adhesion and in vitro differentiation of bone marrow-derived canine MSCs. The benefit of basic fibroblast growth factor (bFGF) on the differentiation of cells in culture was also tested. MSCs were collected from dog bone marrow, isolated and grown on collagen scaffolds with or without HA. Cell viability, proliferation rate, and cellular toxicity were analyzed after 7 days. The cultured cells showed uniform growth and morphological characteristics of undifferentiated MSCs, which demonstrated that MSCs successfully adapted to the culture conditions established by collagen scaffolds with or without HA. This demonstrates that such scaffolds are promising for applications to tissue regeneration. bFGF significantly increased the proliferative rate of MSCs by 63% when compared to groups without the addition of the growth factor. However, the addition of bFGF becomes limiting, since it has an inhibitory effect at high concentrations in culture medium.

Avaliação radiográfica de cães com displasia coxofemoral tratados pela sinfisiodese púbica / Radiographic evaluation in dogs with hip dysplasia treated by pubic symphysiodesis

Avaliou-se a progressão dos sinais radiográficos de cães com displasia coxofemoral ou potencialmente displásicos tratados pela técnica da sinfisiodese púbica. Foram utilizados 14 cães, seis machos e oito fêmeas, com idades entre quatro e seis meses. Após exame físico, procedeu-se ao exame radiográfico para avaliação da articulação coxofemoral, segundo padrão estabelecido pelo Colégio Brasileiro de Radiologia Veterinária. Três deles foram também avaliados pelo método PennHIP. Pelo histórico clínico, nove (64 por cento) animais foram trazidos por manifestarem sinais de dificuldade locomotora com os membros pélvicos, manifestada especialmente por claudicação unilateral ou bilateral e dificuldade de se levantar. Cinco (36 por cento) cães não tinham qualquer sinal clínico, e em quatro (29 por cento) realizou-se o exame radiográfico como prevenção. O sinal físico mais evidente foi dor à palpação da articulação coxofemoral, e dois (14 por cento) cães apresentaram sinal de Ortolani positivo. Com exceção de um cão que apresentou infecção nos pontos cutâneos, todos os demais evoluíram sem complicações no período pós-operatório. Radiograficamente houve progressão das lesões articulares em seis (43 por cento) animais e oito (57 por cento) mantiveram a classificação inicial. Concluiu-se que cães tratados pela sinfisiodese púbica não apresentam melhora dos sinais radiográficos iniciais.

The radiographic findings in hip dysplastic or potentially hip dysplastic dogs treated by the pubic symphysiodesis were evaluated using 14 dogs - six males and eight females -, aging from four to six-month-old. After physical examination, the hip joint was evaluated by radiographic examination according to pattern established by the Colegio Brasileiro de Radiologia Veterinária. In addition, three dogs were evaluated by PennHIP method. According to medical history, nine (64 percent) dogs were admitted due to signs of locomotor difficulty in pelvic limbs, especially characterized by uni or bilateral lameness and stiffness on rising. Five (36 percent) dogs had no clinical signs. Radiographic examination was performed in four (29 percent) dogs as prevention. The most evident physical sign was pain on manipulation of the hip with Ortolani-positive in two (14 percent) dogs. Except for one dog that presented infection signs in the skin suture, no other postoperative complication was observed. The follow-up radiographic examination revealed progression of the degenerative articular changes in six (43 percent) dogs, and eight (54 percent) had no progression. In conclusion, the dogs treated by pubic symphysiodesis did not have improvement of the preoperative radiographic signs.

Radiographic measurement of tibial joint angles in sheep.

The aim of this study was to establish normal reference values of anatomic and mechanical joint angles of the tibia in sheep at different age groups. Eighteen clinically healthy Santa Ines sheep were used. The animals were divided into three equal groups according to age: Group I - from six- to eight-months-old, Group II - 2-years-old, Group III - from three- to five-years-old. Anatomic medial proximal and lateral distal tibial angles, mechanical proximal and distal tibial angles, and anatomic caudal proximal and anatomic cranial distal tibial angles were measured from tibiae radiographs (n = 36). In the craniocaudal view, the mean values of the anatomic medial proximal, anatomic lateral distal, mechanical medial proximal, and mechanical lateral distal tibial joint angles were 89.6 masculine, 86.6 masculine, 91.4 masculine, and 85.19 masculine respectively. In mediolateral view, the mean values of the anatomic caudal proximal and anatomic cranial distal tibial angles were 64.55 masculine and 105.69 masculine, respectively. The joint orientation angles of the tibia in sheep showed similar values regardless of animal age for both anatomic and mechanical axes.

Synthesis Pengo System plates for the treatment of long-bone diaphyseal fractures in dogs.

A Brazilian orthopaedic company designed a stainless steel plate called Synthesis Pengo System (S.P.S.), which has one fixed and one changeable extremity. According to the assembly of the changeable extremity, it is possible to obtain dynamization or neutralization of the fracture site. Since the S.P.S. plate was developed for use in human patients, the aim of this study was to evaluate this system in long-bone diaphyseal fractures in dogs. Eight dogs with closed diaphyseal fractures of the femur (n= 1), radius and ulna (n=5), and tibia (n=2) were used. Patients were aged seven months to three years and weighed 18 to 31.2 kg. The S.P.S. plate was assembled with one fixed extremity and one changeable extremity in dynamization mode. The trail bar was positioned for synthesis modules with holes for cortical screws. The modules were positioned close to one another in two fractures and far away from the fracture site in the others. The bone healing occurred by external callus. Since motion at the fracture site determines the amount of callus required, the secondary bone healing that was observed in all of the cases indicated less rigid fixation of this system. A potential benefit of this system was a lesser interface contact with the bone since it was only done by trail bar. The major disadvantage was the prominence of the implant. It was possible to conclude that the S.P.S. plate appears to be a suitable method for the treatment of diaphyseal fractures in dogs.