P2. Effects of smoking status on metabolic response of cervical and lumbar degenerative intervertebral discs

BACKGROUND CONTEXT

Many studies have validated the clinical signficance of smoking on disc degeneration and adverse outcome in spine health. A paucity of literature exists on the relationship between the biomarkers and the disc degeneration.

PURPOSE

Smoking is associated with IVDD (intervertebral disc degeneration). This study was designed to characterize metabolic responses in cervical and lumbar IVDs based on smoking status.

STUDY DESIGN/SETTING

All patients undergoing elective anterior cervical fusion, lumbar discectomy and lumbar interbody fusion in an ongoing disc biomarker study were included after the IRB approval and obtaiing informed consent.

OUTCOME MEASURES

Significance between smoking status with region and Pfirrmann grade were determined using a One-Way ANOVA with Tukey post-hoc analysis with significance set at p<0.05. Smoking was recorded as nonsmoking (NS), former smoker (FS) or current smoker (CS).

METHODS

IVD tissues from surgery were recovered, and two explants/IVD were created. They were cultured for 3 days and tested for MMPs (1, 2, 3, 7, 8, 9, 13), TIMPs (1, 2, 3, 4), GRO-α, MCP-1, MCP-3, TNF-α, IL-1RA, IL-6, IL-8, MIP-1α, MIP-1ß, RANTES, PGE2, PDGF-AA, PDGF-AB/BB, and VEGF using Luminex assays.

RESULTS

Lumbar IVDs from FS produced significantly lower IL-RA and MMP-13 compared to NS, and MMP-7 compared to CS. Cervical IVDs from CS produced significantly higher levels of MMP-2, MCP-1, RANTES, IL-1RA, and PDGF-ABBB, and lower levels of MCP-3, compared to NS and/or FS. FS produced significantly lower levels of MMP-8 compared to NS and CS. For NS and CS, inflammatory and degrative biomarkers increased as Pfirrmann grade increased. FS produced significantly lower levels of MMP-8 compared to NS and CS. At Pfirrmann grade 4, NS produced lower levels of TIMP-3 and TIMP-4 than FS, and FS produced lower levels of MMP-2 than CS.

CONCLUSIONS

CS produced significantly higher levels of inflammatory and degradative biomarkers at each Pfirrmann grade. FS produced significantly lower levels of MMP-8. NS produced significantly lower levels of MMP-2 and RANTES at Pfirrmann grade 3 and MMP-7 at Pfirrmann grade 5 than CS. NS and FS produced lower levels of PDGF-AB/BB than CS. Inflammatory and degradative biomarkers increased as Pfirrmann grade increased in NS more than CS. Smoking has a greater effect on cervical IVD responses than lumbar IVD.

FDA DEVICE/DRUG STATUS

This abstract does not discuss or include any applicable devices or drugs.