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.