A naturally occurring hormone may hold the key to treating chronic back pain by addressing its biological root causes, according to recent research. Studies suggest that parathyroid hormone (PTH), a hormone produced by the body, could offer a new therapeutic avenue for the condition.
Research published in the Journal of Bone Research indicates that PTH treatment in mice demonstrated an ability to tackle various forms of back pain at their origin. PTH plays a role in calcium regulation and bone metabolism, typically increasing calcium absorption and strengthening bone. While synthetic PTH has been used to treat hypoparathyroidism and osteoporosis, a significant number of patients have anecdotally reported a reduction in back pain as an additional benefit.
In the study, mice were administered daily injections of PTH for up to two months. Researchers observed that the treated mice exhibited denser and more stable vertebral endplates, the bone and cartilage layers separating spinal discs. These mice also showed decreased sensitivity to pain, greater tolerance to pressure, and increased activity levels.
Beyond enhancing bone density, PTH was found to physically deter pain-sensing nerves from damaged spinal areas. This occurs as PTH stimulates osteoblasts, bone-building cells, to release a protein called Slit3, which repels nerves. Dr. Janet Crane, the research lead, explained that in cases of spinal degeneration, pain-sensing nerves can grow into areas where they typically do not exist. The findings suggest that parathyroid hormone can reverse this process by activating natural signals that push these nerves away.
This mechanism suggests that PTH could potentially 'rewire' pain signals at their source, offering a way to permanently reverse the biological causes of chronic back pain, rather than merely providing temporary relief as is often the case with painkillers or anti-inflammatory drugs.
Consultant spinal surgeon Bob Chatterjee noted that this discovery is promising, building upon existing knowledge of PTH. He cautioned that PTH is not a universal cure but shows potential for specific conditions. Back pain can stem from various factors, including injury, congenital issues like scoliosis, arthritis, and lifestyle choices such as prolonged sitting, smoking, or obesity. Chatterjee indicated that this research specifically targets structural back pain, which involves the degeneration of spinal components like discs and joints. This degeneration can be linked to aging, abnormal stress from poor posture, or injury.
Reports suggest that up to 40% of patients experience structural back pain, with the majority being over 50. For pain originating from degeneration within the vertebral endplates, PTH's ability to strengthen bone and repel nerves from sensitive areas appears beneficial. It may also help with pain arising from damaged or arthritic facet joints, which can promote the growth of abnormal nerve endings.
However, the hormone might be less effective for pain caused by muscle or ligament damage, such as whiplash, or pain primarily driven by lifestyle factors. Potential side effects of PTH treatment could involve disruptions to calcium metabolism. Chatterjee warned that low blood calcium can lead to nerve hyper-excitability, causing symptoms like numbness and muscle cramps, while excessively high calcium levels can result in fatigue, brain fog, sleep disturbances, and irritability.
Current treatments for back pain often include physiotherapy, osteopathy, acupuncture, medications, steroid injections, and surgery. Chatterjee pointed out that these methods often treat the symptoms rather than the underlying cause, whereas PTH therapy theoretically addresses the root of the problem.