Stem cells are cells of the human body that have particular potential to repair damaged tissues. This is also the main reason for the strong interest of the global medical community in recent years. Stem cells are cells that can differentiate into other types of cells, and can also divide in self-renewal to produce more of the same type of stem cells.

Stem cells have two main characteristics:

• Mesenchymal stem cells are multipotent cells with a high capacity for self-renewal
• They can differentiate into other types of cells
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There are two types of stem cells: embryonic stem cells and adult stem cells.

In modern orthopedic surgery, adult stem cells are the dynamic choice for the regeneration and regeneration of articular cartilage and other tissues. Articular cartilage does not have the ability to regenerate and repair itself as most body tissues have. In osteoarthritis, there is a gradual degeneration and deterioration of the articular cartilage that results in some cases of complete loss of it and the appearance of pain and stiffness in the joint.

Treatment with autologous stem cells is primarily aimed at inhibiting the progressive progression of the disease and creating new cartilage cells preventing the necessity of arthroplasty surgery (arthroplasty).

Stem cells are the most potent choice for the treatment of osteoarthritis because:

• It is relatively easy to collect and isolate
• Easily propagated and cultivated, maintaining their potential and properties
• Easy to apply to joints while maintaining their main features

OA is characterized by progressive cartilage degradation, subchondral bone remodeling, bone marrow lesions, meniscal damage, and synovitis [17]. Innate immune cells (natural killer (NK) cells, macrophages and mast cells) play the most important pathogenic role in the early inflammatory response, while cells of adaptive immunity (CD4+Th1 lymphocytes and antibody producing B cells) significantly contribute to the development of chronic, relapsing course of inflammation in OA patients. Macrophage-derived inflammatory cytokines (tumor necrosis factor alpha (TNF-α) and interleukin (IL)-1β) shift synovial tissue homeostasis towards catabolism by promoting production of matrix degrading enzymes that results with an increased bone and cartilage resorption. This creates the vicious cycle of inflammation - arthritis - pain.

Mesenchymal stem cells, MSCs, are multipotent cells with a high capacity for self-renewal. Although bone marrow (BM) and adipose tissue (AT) have been most usually used as sources for the isolation of MSCs. Thus, mesenchymal stem cells are heterogenous population of cells with variable growth potential, distinct morphologic and functional characteristics, but all of them have chondrogenic potential and potent immunosuppressive characteristics, representing a powerful tool in the therapy of OA. MSCs inhibit activation of inflammatory M1 macrophages and promote their conversion in antiinflammatory, M2 phenotype; attenuate proliferation and cytotoxicity of NK cells (Natural Killer cells), prevent activation of autoreactive B cells and production of autoreactive antibodies. All of these have the beneficial effect of inhibiting the progression of arthritis to relieve pain and improve the mobility of the articular joint.

See for stem cell treatment of Avascular femoral head necrosis - osteonecrosis...

BONE MAROW STEM CELLS

The bone marrow procedure is performed under surgical conditions by the pelvis (bone marrow aspiration). The patient is under light sedation. The quantity obtained does not exceed 20 cc. Immediately after aspiration, special processing of the bone marrow begins, resulting in the isolation of stem cells (3-4cc), which are injected into the affected joint. The total time from aspiration, processing and injection does not exceed 20 minutes. The patient leaves the clinic with instructions to rest for 48 hours.

ADIPOSE TISSUE

The adipose tissue is taken from the patient's abdomen where it is usually found in sufficient quantity. With a special trocar, 2-3cc of adipose tissue is obtained and sent directly to a specialist regenerative biotechnology company where the stem cells are isolated, cultivated and proliferated for approximately 5 weeks to achieve a sufficient number, usually twenty million stem cells. After weeks, the stem cells are injected into the affected joint. The whole procedure is done at the medical office and does not require an introduction to the clinic. Stem cell therapy can be ideally combined with arthroscopic procedure to correct all areas of articular cartilage damage as well as the cause of the damage (neglected torn of meniscus or anterior cruciate ligament).

Osteoarthritis has for many years been a disease for which medicine could only administer painkillers and anti-inflammatory drugs. Nowadays, knowledge of the pathogenesis of the disease as well as the evolution of biotechnology enables the specialist orthopedic surgeon to interfere with the development of the disease, relieve pain and stiffness and improve the quality of life of patients.