20 Nov Intervertebral Disc Herniation – Potential Role of Stem Cell Therapy
Low back pain is the most common health problem for men and women between 20 and 50 years of age. Intervertebral disc (IVD) degeneration, which includes associated problems such as herniation, is one of the main causes of low back pain. IVD degeneration is been considered to be an irreversible process that is characterized by a decrease in cell viability, attenuation of proteoglycan and type II collagen synthesis, and dehydration of nucleus pulposus. There are a few treatment options for IVD-related back pain, such as selective nerve root blocks, surgical discectomy, and fusion, but they are costly and provide symptomatic relief.
Mesenchymal stem cells (MSCs) are pluripotent cells found in the body (bone marrow, adipose tissue, umbilical cord, etc.). MSC has the ability to migrate and engraft within various tissues, and stimulate other cell types through various mechanisms. They can differentiate into nucleus pulposus-like cells capable of synthesizing a physiological extracellular matrix. These characteristics make MSCs a potential source of curative treatment for IVD disease.
There are challenges regarding survival and proliferation of stem cells within the degenerating disc that needs to be addressed; however, MSC has the potential to slow or reverse the degenerative process.
Recent in vivo studies demonstrate that transplanted MSCs survive and successfully engraft into the IVD tissue, and can also channel therapeutic genes into the tissue (gene therapy). MSC migration and proliferation into the IVD can be evidenced by an increase in the intradiscal magnetic resonance imaging T2 signal intensity, increases the disk height, and decreases the degenerative grade.
All of the current surgical and non-surgical therapies for IVD degeneration focus only on symptom relief. Adult mesenchymal stem cells (MSC) offer a potentially curative treatment for IVD degeneration. They are easily procured by bone marrow aspiration or adipose tissue lipoaspirate. They are more capable of differentiating and adapting successfully to the environment of the disc.
MSC are undifferentiated, multipotent cells that can differentiate various cell types, including bone, cartilage, fat, muscle and tendons. The nucleus pulposus of IVD can also be created by MSCs differentiating into chondrocyte-like NP cells.
It has been shown in rat models that MSCs differentiate into a phenotype similar to that of the NP when exposed to hypoxia. There is a variable degree of inflammation in the IVD in patients suffering from IVD degenerative disease. MSC is found to have immunosuppressive effect on IVD.
After demonstrating that MSC is able to differentiate into NP-like disc cells, in vivo studies were necessary to evaluate the efficacy and safety of this therapeutic option in degenerated discs.
There are a few clinical studies in which stem cells were used in the treatment if IVD degeneration. One study reported the effects of MSC in patients with IVD degenerative disease two years after the initial procedure, with improved symptoms and rates of the Visual Analog Scale score for low back pain, along with radiographic
evidence of improvement in degeneration of IVD. Another study showed rapid improvement in pain and disability at 3 months of IVD degeneration after MSC treatment. However, there appeared to be no improvement in disc height, but the water content of the disc was significantly elevated at 12 months.
There is promise in the use of stem cell therapy for IVD degeneration and herniation. This can be a novel therapeutic option for back pain while avoiding extensive surgeries and with less morbidity. The use of this MSC therapy is still experimental and more research studies are warranted to establish its safety and efficacy.