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

Abstract

<h3>BACKGROUND CONTEXT</h3> 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. <h3>PURPOSE</h3> 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. <h3>STUDY DESIGN/SETTING</h3> 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. <h3>OUTCOME MEASURES</h3> 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). <h3>METHODS</h3> 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. <h3>RESULTS</h3> 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. <h3>CONCLUSIONS</h3> 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. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.