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MONTREAL – A novel approach targeting harmful “zombie cells” in the spine could pave the way for revolutionary treatments for chronic lower back pain, according to researchers at McGill University. In a promising preclinical study, scientists demonstrated that eliminating these senescent cells not only reduced pain but also potentially reversed spinal disc damage in mice.
Lower back pain remains a leading cause of disability worldwide, affecting millions and placing a significant burden on healthcare systems. Current treatments, often limited to pain relievers, physical therapy, or surgery, primarily manage symptoms rather than addressing the underlying pathology.
The McGill team, based at the Orthopaedic Research Laboratory at the Montreal General Hospital, investigated a different strategy: eliminating senescent cells. These “zombie cells” evade their natural death cycle and accumulate in tissues, particularly with age or injury. In the spine, they gather in the intervertebral discs – the crucial cushions between vertebrae – releasing a cocktail of inflammatory and tissue-degrading molecules known as the senescence-associated secretory phenotype (SASP). This process fuels disc degeneration and chronic pain.
“Our findings are exciting because it suggests we might be able to treat back pain in a completely new way, by removing the cells driving the problem, not just masking the pain,” said Professor Lisbet Haglund, senior author of the study published in Science Advances.
Using a specialized mouse model prone to early-onset disc degeneration similar to humans, the researchers tested two compounds: o-Vanillin, a natural anti-inflammatory derived from turmeric, and RG-7112, a synthetic drug initially developed for cancer therapy known to interfere with mechanisms that keep senescent cells alive.
Administered orally over eight weeks, both drugs showed positive effects individually, but their combination yielded the most significant results. The treatment successfully:
- Cleared senescent cells from the spinal discs (indicated by reduced p16Ink4a levels).
- Reduced inflammation by lowering levels of damaging SASP factors like IL-6, TNF-α, and VEGF-α.
- Showed signs of reversing disc damage, improving disc structure and volume.
- Alleviated pain-related behaviours in the mice, including improved grip strength and reduced sensitivity.
Crucially, the therapy also appeared to calm pain signalling within the nervous system. Researchers observed lower activity of pain-associated proteins (CGRP, GFAP) and reduced activation of pain-amplifying immune cells (microglia) in the spinal cords of treated mice.
“We were surprised that an oral treatment could reach the spinal discs, which are hard to access and present a major hurdle in treating back pain,” Haglund noted. The ability of o-Vanillin, in particular, to potentially penetrate these tough tissues was a key finding, prompting further investigation into optimizing its structure for longer-lasting effects.
Encouragingly, the drug doses used in the mice appear translatable to feasible and potentially safe levels in humans, falling below toxic thresholds observed in other applications of RG-7112. No adverse effects were noted in the mice during the trial.
While these findings represent a significant step forward, the researchers stress that further studies, including trials in larger animal models and investigations into optimal drug delivery, are necessary before human trials can commence.
“The big question now is whether these drugs can have the same effect in humans,” Haglund added.
If successful, this senolytic approach – targeting senescent cells – could represent a paradigm shift not only for back pain but potentially for numerous other age-related conditions like arthritis and osteoporosis, where zombie cells are implicated.
Disclaimer: This news article is based on preclinical research conducted in animal models (mice). The findings, while promising, have not yet been validated in human clinical trials. The potential treatments discussed are not currently approved for human use for back pain, and their safety and efficacy in humans are unknown. Consult with healthcare professionals for any medical advice or treatment options.
