Introduction

       

         In recent years, stem cell therapy has become an up-and-coming and advanced scientific research field. Stem cells are commonly used for treating injured tissues or organs in regenerative medicine and have the capacity to self-regenerate or differentiate into tissues and organs. Stem cells are the most potent cells in regenerative medicine. Conventional conservative medical treatments for knee osteoarthritis (OA) are aimed at symptomatic control rather than disease modification. Patients with OA often receive anti-inflammatory drugs, analgesic drugs, hyaluronic acid, or platelet-rich plasma to relieve pain. More OA patients prefer to receive the new medical therapy as early as possible to manage their symptoms and prevent or delay the progression of OA.

What are the Mesenchymal Stem Cells? 

         Adipose-derived mesenchymal stem cells (ADSCs) are undifferentiated multipotent cells characterized by the capacity for self-renewal and the ability to differentiate into various cells of mesenchymal origin, including adipocytes chondrocytes, myocytes, and osteoblasts when exposed to specific growth signals and cytokines. In addition, MSCs secrets multiple growth factors and cytokines for promoting injured tissue and organ tissue repair.

       Human ADSCs have gained attention due to their potential to expedite healing and the ease of harvesting. Notably, the expansion culture of ADSCs should be satisfied with the Good Tissue Practice (GTP) guidelines and amplified to enough cell numbers and pass multiple tests. Finally, the cell product will be intra-articular injected into damaged cartilage. The ADSCs not only inhibit the macrophage activity and suppress the inflammatory microenvironments. Furthermore, ADSCs secret cytokines and many growth factors to immunomodulate inflammatory responses, so the isolated and expanded ADSCs can be used for the treatment of OA. Importantly the significant pain and functional improvement and observed disease modification indicate that MSCs therapy represents an exciting potential advancement in the treatment of OA.

As for using bone marrow mesenchymal stem cells (BMMSCs) in treating cartilage defect, needle bone marrow aspiration will be performed and used for in vitro culture of BMMSCs, which will further induced into chondrocytes precursor and forming engineered cartilage tissue. This cartilage tissue then can be used in surgery for cartilage defect treatment.

The Regulations of Cell Therapy in Taiwan

      In 2018, the amended "Regulations Governing the Application or Use of Specific Medical Techniques or Examinations, or Medical Devices" has passed and cell therapy for clinical treatments were allowed in Taiwan. The autologous MSCs can be administrated in patients with OA and cartilage defect. Autologous and allogenous MSCs have advantages and disadvantages in preclinical and clinical practice. Autologous MSCs are easy to obtain and lack immune rejection after infusion. However, the potential risks and limitations of using autologous MSCs for therapeutic applications are still highly debated, such as the potential impact of biological heterogeneity. As for using allogenous MSCs, the potential of immune rejection also raises the concerns. So far, autologous ADSCs is still the main stream in treating OA and cartilage defect.