pH: A major player in degenerative intervertebral disks.

Area of Science:

• Biomedical Sciences
• Pain Research
• Spinal Health

Background:

• Chronic lower back pain (LBP) is a leading global disability, with degenerative disk disease (DDD) being a primary cause.
• Current understanding of DDD's contribution to LBP mechanisms is incomplete, despite identified factors like ECM breakdown and inflammation.
• The role of low pH (hyperacidity) in DDD pain generation is underappreciated and warrants further investigation.

Purpose of the Study:

• To review the known effects of hyperacidity on the intervertebral disk (IVD) in the context of DDD.
• To identify knowledge gaps regarding the contribution of acidity to DDD-associated pain.
• To propose future research directions for understanding acidity's role in DDD pain and developing targeted therapeutics.

Main Methods:

• Literature review synthesizing current knowledge on hyperacidity and DDD.
• Analysis of studies investigating cellular and molecular changes in the IVD due to low pH.
• Identification of research gaps and formulation of recommendations for future studies.

Main Results:

• Hyperacidity contributes to DDD by promoting disk cell and ECM catabolism.
• Low pH influences neoinnervation, alters mechanical signaling, and affects the expression of pro-inflammatory cytokines and ion channels within the IVD.
• Existing therapeutic approaches for DDD pain have shown limited efficacy.

Conclusions:

• Acidity is a significant, yet underappreciated, factor in the pathophysiology of DDD and associated LBP.
• Further research is crucial to elucidate the interaction between hyperacidity and nociception in DDD.
• A better understanding of these mechanisms is essential for developing more effective treatments for DDD pain.