Chronic pain has become a huge problem in the United States. From prolonged pain after an injury, to pain conditions like fibromyalgia that come on unexpectedly, there are about 20.9% of Americans that experience chronic pain.1 That’s about 51.6 million people!
What is Chronic Pain?
While we all experience the occasional aches and pains, from paper cuts, bumps and bruises and broken bones, these tend to heal within a couple of weeks or months. Chronic pain, on the other hand, is defined as pain that lasts longer than 12 weeks.2 The type of pain can come in different forms; sharp, dull, burning, or aching. I can be steady and persistent or come on intermittently and can be in nearly any part of your body. There are several different categories of chronic pain.
Chronic pain is usually triggered by an injury. This could be a muscle strain, joint sprain or other sort of trauma. In these cases, the nerve damage makes pain more intense and longer lasting. While chronic pain from injury is most common, the trigger of some people’s pain is unknown.
There are different types of pain:2
- Neuropathy is pain that comes from nerves that are damaged or not working properly. It’s like having frayed wires in an electric system. The signals don’t get delivered as effectively.
- Nociceptive pain comes from actual tissue injury like burns, bruises or sprains to tendons and ligaments. It acts as your body’s alarm system to let you know there is a potential problem or injury.
- Musculoskeletal pain is caused by injury to the muscles and connective tissues. This can be muscle tears, strains, or bruising.
- Inflammatory pain comes from autoimmune disorders, like rheumatoid arthritis or infections that cause inflammation in the body. Inflammation comes from a response to injury or illness, as a natural healing process.
- Psychogenic pain is a result of emotional, psychological or behavioral disorders rather than a physical cause. These are often experienced where someone is going through intense stress, depression, anxiety or trauma, but there is no biological explanation for the pain.
- Mechanical pain occurs when muscles, joints or bones are strained, pulled, or twisted in ways that they shouldn’t be. This pain acts as the body’s signal that something has been used incorrectly and needs to rest to avoid further pain and damage.
- Fibromyalgia is a unique condition where one experiences various pain throughout the body. It’s usually accompanied by fatigue, difficulty sleeping, and emotional and mental stress.
This type of pain isn’t caused by physical injury but is linked to how the body gets a heightened sensitivity to pain due to an issues with how the brain and spinal cord process pain.
Many of these can exist together, for example, you can have both back pain and fibromyalgia.
What are UC-MSCs
Stem cells form the fundamental cellular base of the body, acting as a master key for all other cell types. Their main role is to replace cells that are dying and to repair tissues that are damaged. We are naturally born with a store of stem cells to help support these processes throughout our lives.
Among the diverse types of stem cells, Mesenchymal stem cells (MSCs) are particularly noteworthy due to their unique abilities. They can transform into a range of cells such as those found in bone, cartilage, and fat, and possess the ability to self-renew, ensuring their population remains stable over time. This is essential for therapeutic applications.3
MSCs are found in three main places in the body; bone marrow, umbilical cord blood, and adipose tissue. Umbilical cord MSCs (UC-MSCs) have generally demonstrated to be the most effective compared to other types. They proliferate more rapidly and can evolve into the three primary layers of cells, playing a vital role in tissue repair.4
Furthermore, UC-MSCs offer several additional advantages. They can be easily collected, present lower risks of infection and tumor formation, have the potential to develop into various cell types, and are less likely to provoke immune reactions. These qualities, coupled with their ethical acceptability, position UC-MSCs as a highly promising option in a range of clinical contexts.
How UC-MSCs can help with nerve pain
Treating nerve pain presents a significant challenge for many doctors. While the body has some ability to regenerate nerve cells and achieve some level of functional recovery, this natural process is limited and often insufficient. Current treatments, including such as neurorrhaphy, which involves stitching a severed nerve back together, and neurolysis, the use of chemicals to inhibit nerve function, are not consistently reliable and frequently result in high failure rates.
In searching for a new treatment option, UC-MSCs have been emerging due to their unique cellular repair capabilities. Compared to untreated groups, patients that were treated with UC-MSCs had significantly better nerve healing.5 This included repair of the protective layer around the nerve cells called the myelin sheath, in crushed nerves, and improvements movement, nerve growth and reduced muscle weakening and better nerve function (signal transmission) in animal models.
When treating spinal cord injuries, transplanting UC-MSCs lead to improved functional recovery and reduced symptoms of neuropathic pain. This includes conditions like allodynia, where a normally painless touch can cause significant pain, and hyperalgesia, where a mildly painful stimulus results in disproportionately severe pain. 5 This study used both bone marrow-derived and UC-MSCs and found that UC-MSCs had a notably higher survival rate and had better outcomes.
UC-MSC exosomes have even shown therapeutic benefits. Exosomes are small extracellular vesicles that play a key role in how cells communicate. They can carry important materials from cell to cell, influencing different physical and physiological processes in the body. In an animal model of spinal nerve damage, an injection of exosomes reverse mechanical and thermal hypersensitivity.7 Regularly injecting exosomes directly into the spinal fluid greatly helped both in preventing and reducing pain caused by nerve damage.
The takeaway
In a world where chronic pain ranks as a major health concern, finding effective treatments is crucial. Nerve pain stands out as particularly challenging and difficult to manage. Emerging research highlights the promise of UC-MSCs as a treatment for these pain conditions. These cells not only have the capacity to repair and restore function but their exosomes also offer a promising non-cellular treatment option. As we delve deeper into the capabilities of these powerful cells for neuropathic and other types of pain, there’s growing excitement about their therapeutic potential.
Resources:
- Rikard, S. M. (2023). Chronic Pain Among Adults—United States, 2019–2021. MMWR. Morbidity and Mortality Weekly Report, 72. https://doi.org/10.15585/mmwr.mm7215a1
- Dydyk AM, Conermann T. Chronic Pain. [Updated 2023 Jul 21]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK553030/
- Stem Cell Basics | STEM Cell Information. National Institutes of Health. https://stemcells.nih.gov/info/basics/stc-basics.
- Stem Cells: Types, What They Are & What They Do. Cleveland Clinic. https://my.clevelandclinic.org/health/body/24892-stem-cells
- Bojanic, C., To, K., Zhang, B., Mak, C., & Khan, W. S. (2020). Human umbilical cord derived mesenchymal stem cells in peripheral nerve regeneration. World journal of stem cells, 12(4), 288–302. https://doi.org/10.4252/wjsc.v12.i4.288
- Yousefifard, M., Nasirinezhad, F., Shardi Manaheji, H., Janzadeh, A., Hosseini, M., Keshavarz, M. 2016. Human bone marrow-derived and umbilical cord-derived mesenchymal stem cells for alleviating neuropathic pain in a spinal cord injury model. Stem Cell Res Ther 7, 36 . https://doi.org/10.1186/s13287-016-0295-2
- Shiue, S. J., Rau, R. H., Shiue, H. S., Hung, Y. W., Li, Z. X., Yang, K. D., & Cheng, J. K. (2019). Mesenchymal stem cell exosomes as a cell-free therapy for nerve injury-induced pain in rats. Pain, 160(1), 210–223. https://doi.org/10.1097/j.pain.0000000000001395
