A recent study conducted by scientists at the Johns Hopkins University School of Medicine suggests that low back pain, a common issue that affects many individuals, may soon be a thing of the past. The research, published in the journal eLife, identified senescent cells, also known as "sleeping" cells, as the main cause of back pain. These cells make the bones of the spine porous, allowing nerve fibers to fill the empty spaces. When these nerve fibers become irritated or pinched, back pain occurs.
Back pain is a prevalent problem, particularly among older adults. Musculoskeletal pain affects a significant percentage of older individuals, estimated to be between 65% to 85%. Back pain specifically accounts for 36% to 70% of musculoskeletal issues in this population. While it was previously believed that back pain peaks around the age of 60 and then decreases, recent studies indicate that pain remains common even in later years. In fact, individuals over the age of 80 are three times more likely to experience severe low back pain compared to middle-aged adults.
Once back pain sets in, individuals often become inactive due to the pain. This inactivity can lead to a reduction in participation in various activities and gatherings, ultimately decreasing quality of life. Despite the prevalence of back pain, the cellular causes remain poorly understood, resulting in mixed results with therapeutic interventions. Specifically, non-specific low back pain, where the cause is unclear, often only sees short-term relief with treatment.
The researchers in this study focused on senescent osteoclasts, which are retired cells that have stopped dividing and working. As we age, these cells accumulate and release inflammatory molecules that can harm nearby cells and cause inflammation in various tissues, leading to age-related health problems. Previous research by the same laboratory discovered that these osteoclasts play a role in the formation of pores in the endplates of the vertebrae, which are crucial for the spine's structure and function.
To test their hypothesis, the researchers examined mice with spine hypersensitivity caused by old age or lumbar spine instability. Biomarkers indicated the presence of senescent osteoclasts in the endplates, and the more biomarkers present, the more porous the endplates and the more sensitive the spine. The researchers then administered an experimental drug called Navitoclax, which targets and destroys senescent cells. Treatment with Navitoclax resulted in a reduction in senescent osteoclasts, less porous endplates, and fewer signs of degeneration. The mice also experienced reduced pain and increased activity levels.
These findings are promising and open the door for further research. If future studies confirm these results, it could lead to new treatments for low back pain and improve the quality of life for those suffering from this condition.