Related Experiment Video
Updated: Feb 23, 2026
A Proinflammatory, Degenerative Organ Culture Model to Simulate Early-Stage Intervertebral Disc Disease.
Published on: February 14, 2021
Inflammatory response of disc cells against Propionibacterium acnes depends on the presence of lumbar Modic changes
Stefan Dudli1,2, S Miller3, S Demir-Deviren4
1Department of Orthopaedic Surgery, University of California San Francisco, 513 Parnassus Ave, S-1164, San Francisco, CA, 94143, USA. dudli@panamerica.ch.
Purpose:
Intervertebral disc with Propionibacterium acnes (P. acnes) is suggested to be an etiology of Modic type I changes in the adjacent bone marrow. However it is unknown if disc cells can respond to P. acnes and if bone marrow cells respond to bacterial and disc metabolites draining from infected discs.
Methods:
Human disc cells (n = 10) were co-cultured with 10- and 100-fold excess of P. acnes over disc cells for 3 h and 24 h. Lipopolysaccharide was used as positive control. Expression of IL1, IL6, IL8, and CCL2 by disc cells was quantified by quantitative PCR. Lipase activity was measured in culture supernatants (n = 6). Human vertebral bone marrow mononuclear cells (BMNCs) (n = 2) were cultured in conditioned media from disc cell/P. acnes co-cultures and expression of IL1, IL6, IL8, and CCL2 was measured after 24 h.
Results:
All disc cells responded to lipopolysaccharide but only 6/10 responded to P. acnes with increased cytokine expression. Cytokine increase was time- but not P. acnes concentration-dependent. Disc cell responsiveness was associated with the presence of lumbar Modic changes in the donor. Lipase activity was increased independent of disc cell responsiveness. BMNCs responded with inflammatory activity only when cultured in supernatants from responsive disc cell lines.
Conclusion:
Disc cell responsiveness to P. acnes associates with the presence of lumbar Modic changes. Furthermore, bone marrow cells had an inflammatory response to the cocktail of disc cytokines and P. acnes metabolites. These data indicate that low virulent P. acnes infection of the disc is a potential exacerbating factor to Modic changes.
Insights
Propionibacterium acnes (P. acnes) infection in intervertebral discs may worsen Modic changes. Disc cells respond to P. acnes, and bone marrow cells react to disc and bacterial byproducts, suggesting a link to spinal changes.
Area of Science:
- Spinal pathology and microbiology
- Immunology and cellular response
Background:
- Modic type I changes are linked to intervertebral disc infections.
- The response of disc and bone marrow cells to Propionibacterium acnes (P. acnes) remains unclear.
Purpose of the Study:
- To investigate disc cell and bone marrow cell responses to P. acnes.
- To determine if P. acnes infection exacerbates Modic changes.
Main Methods:
- Human disc cells were co-cultured with P. acnes, and cytokine expression (IL1, IL6, IL8, CCL2) was measured.
- Lipase activity in disc cell supernatants was assessed.
- Bone marrow mononuclear cells (BMNCs) were exposed to conditioned media from co-cultures.
Main Results:
- Disc cells showed variable responses to P. acnes, with responsiveness linked to donor Modic changes.
- Increased lipase activity was observed, independent of disc cell responsiveness.
- BMNCs exhibited inflammatory responses only when exposed to supernatants from responsive disc cell lines.
Conclusions:
- Disc cell sensitivity to P. acnes correlates with lumbar Modic changes.
- Bone marrow cells react to a combination of disc cytokines and P. acnes metabolites.
- Low-virulence P. acnes disc infections may contribute to the progression of Modic changes.
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