
One of the main causes of joint pain is the wear and tear of hyaline articular cartilage, which covers the bone in the area of the joint surfaces.
However, the disadvantage of hyaline cartilage is its extremely limited ability to regenerate and heal, making the treatment of traumatic cartilage damage in particular problematic. The aim of all surgical therapies is to achieve regeneration of the defect through local stimulation or through the transplantation of tissue or chondrocytes. However, the procedures currently in use, such as the osteochondral autograft transfer system (OATS) and autologous chondrocyte transplantation (ACT), as well as micro- and nanofracturing, have some significant disadvantages. Due to the limitations of the aforementioned methods, there is currently growing interest in using tissue engineering to treat cartilage defects. So-called cell-scaffold combinations are used to regenerate damaged cartilage tissue. With the use of tissue engineering, some significant improvements in the treatment of chondral defects are possible compared to previously known procedures. For example, the morbidity of harvesting could be reduced and the limited availability of the starting material could be overcome.
Mesenchymal stromal cells (MSC) are a promising cell source for tissue engineering, as they can be isolated from the body’s own tissues, making autologous application possible. Furthermore, MSC are multipotent, which enables them to differentiate chondrogenically. They also have hypoimmunogenic, immunoregulatory and wound-healing properties. The combination of Scaffold and MSCs has been shown to be beneficial compared to the use of Scaffold or MSCs alone. Many published reviews on cartilage regeneration and the use of MSC cite clinical studies in humans with very good results. However, there is still a great need for evaluation. For example, the qualitative regeneration of hyaline cartilage is still a problem. In addition, the studies differ with regard to the number of MSC applied, whereby a higher number of cells is not necessarily advantageous, although a minimum number of transplanted cells must be exceeded. Furthermore, there are initial in vivo approaches that compare undifferentiated with chondrogenically pre-differentiated MSC, whereby the pre-differentiated MSC have proven to be advantageous. Various methods for transplanting the MSCs used into cartilage defects have also been described. For example, the scaffold can provide a bioresorbable three-dimensional guide structure to support the differentiation of the MSC into the desired tissue structures.
The treatment of cartilage defects represents a growing field of research. Despite the initial promising successes of tissue engineering, many aspects have not been sufficiently clarified or optimized. For example, details such as the optimal cell source, the most effective number of cells, the best possible application, pre-treatment of the MSC and the optimal combination of scaffold and MSC have not been sufficiently evaluated. The plan is to use a minipig model already established at the site to answer initial questions in order to be able to treat cartilage defects in the future through the formation of new hyaline-like cartilage tissue with the help of autologous MSC.