The Holy Grail of Orthopedic Surgery: Mesenchymal Stem Cells-Their Current Uses and Potential Applications

Abstract

Only select tissues and organs are able to spontaneously regenerate after disease or trauma, and this regenerative capacity diminishes over time. Human stem cell research explores therapeutic regenerative approaches to treat various conditions. Mesenchymal stem cells (MSCs) are derived from adult stem cells; they are multipotent and exert anti-inflammatory and immunomodulatory effects. They can differentiate into multiple cell types of the mesenchyme, for example, endothelial cells, osteoblasts, chondrocytes, fibroblasts, tenocytes, vascular smooth muscle cells, and sarcomere muscular cells. MSCs are easily obtained and can be cultivated and expanded in vitro; thus, they represent a promising and encouraging treatment approach in orthopedic surgery. Here, we review the application of MSCs to various orthopedic conditions, namely, orthopedic trauma; muscle injury; articular cartilage defects and osteoarthritis; meniscal injuries; bone disease; nerve, tendon, and ligament injuries; spinal cord injuries; intervertebral disc problems; pediatrics; and rotator cuff repair. The use of MSCs in orthopedics may transition the practice in the field from predominately surgical replacement and reconstruction to bioregeneration and prevention. However, additional research is necessary to explore the safety and effectiveness of MSC treatment in orthopedics, as well as applications in other medical specialties.

Figure 1

Mesenchymal stem cells (MSCs) are broadly applicable to the field of orthopedics. MSCs can be stimulated to differentiate into several cellular lineages with various clinical applications. For example, fibroblasts can be used to regenerate torn or injured tendons, ligaments, menisci, rotator cuff, and intervertebral disc; chondrocytes can be used to regenerate articular cartilage defects and treat osteoarthritis; osteoblasts can facilitate fracture consolidation and treat metabolic bone diseases such as osteogenesis imperfecta, growth cartilage diseases, spinal fusion, and regeneration of segmental defects of the bone after tumor removal; myoblasts can be used to regenerate torn or injured muscles; and neurons can be used to regenerate peripheral nerves or aid in the repair of traumatic spinal cord injuries.

Figure 2

MSC isolation procedure. Blood from a peripheral vein is collected from the patient following the mobilization of MSCs to the peripheral circulation with granulocyte colony-stimulating factor. Mononuclear cells are then separated from other blood components using a density gradient and seeded in cell culture flasks where they will proliferate. Expanded cells can then be stimulated to differentiate into a particular cellular lineage, harvested, and seeded onto a biocompatible scaffold for implantation in the patient, as required.