A Growth Factor and an Anti-Aging Protein May Slow the Most Common Cause of Back Pain
Worn-down spinal discs are behind much of the back pain that becomes nearly universal with age.
Intervertebral discs are the spine’s shock absorbers. Each disc has a tough outer ring and a gel-like center that enables movement and cushions impact. With age, they dry out, stiffen, and develop micro-tears. The result is the chronic lower back pain that limits daily life for hundreds of millions of people worldwide. Intervertebral disc degeneration (IDD) is one of the most prevalent age-related conditions, yet treatment options remain largely focused on managing pain rather than addressing the underlying biology.
A new study, published in Aging Cell and reported by Lifespan.io, investigated whether FGF21 — fibroblast growth factor 21, a protein best known for its role in metabolic regulation — might slow disc aging. The researchers found that FGF21 acts through SIRT1, a member of the sirtuin family: proteins involved in DNA repair, cellular stress responses, and inflammation control. SIRT1 has been a recurring target in aging research, partly because of its role in mediating the effects of caloric restriction.
What happens inside the disc cell
In rats with experimentally induced disc degeneration, FGF21 treatment elevated SIRT1 activity within disc cells. This was accompanied by reduced oxidative damage — harm caused to cells by reactive oxygen molecules — and slower breakdown of the extracellular matrix, the structural scaffold that holds the disc together. In plain terms: the disc cells held up better and showed fewer signs of age-related deterioration.
What makes this finding broader than a niche result is FGF21’s known range of effects. The molecule is already recognized as a regulator of fat metabolism, insulin sensitivity, and protection against obesity-related damage. That the same molecule also influences disc health illustrates how aging in different tissues often runs through overlapping biological pathways.
The distance from rat to human is still enormous
The usual caveats apply here with particular force. Rat models of back pain are notoriously difficult to translate to humans — not only because of anatomical differences, but because humans walk upright, which places entirely different mechanical loads on the spine. FGF21 also has broad systemic effects, meaning that delivering it as a therapy could trigger unintended consequences elsewhere in the body.
Still, the study contributes to a slowly building picture: disc degeneration may not be an inevitable consequence of getting older, but a biological process with identifiable and potentially modifiable mechanisms. Whether FGF21 or SIRT1 activators will ever become clinically practical for back conditions is a question that will take many more years — and very different kinds of studies — to answer.