Table 3.

Summary of biomarker studies of LBP due to disc degeneration

Year	Study	Comparator groups	Number of subjects (N)	Study design	Summary of significant findings	Reference
2012	Goode et al.	Graded scale of disc space narrowing (DSN), osteophyte formation (OST) in patients with and without LBP symptoms	547	Retrospective	Type II collagen (C2C) was associated with DSN;	61
					COMP was associated with DSN among patients. with symptoms;
					HA and C2C are correlated with DSN severity.
2015	Weber, et al.	DH vs. other Dx (DDD/SS); pre- vs. post treatment	16	Longitudinal – prospective	SCGF-β and IL-2 higher posttreatment in all groups compared with pretreatment;	79
					IL-2Ra, IL-3, SCGF-β decreased posttreatment in other Dx; change in pain correlated with change in MCP-1, SCF, IFN-α2, MIG, TRAIL, SCGF-β, IL-6, IL-10, HGF, IL-18; IL-2, IL-3, IL-8, HGF, IFN-α2, LIF, MCP-3, TNF-β higher in other Dx compared with DH;
2016	Deng et al.	DH vs. control	10	Cross-sectional – prospective	IL-6 higher in DH than controls;	78
					Col II and aggrecan lower in DH than controls.
2016	Grad et al.	Degenerate vs. nondegenerate	80	Case control –prospective	CCL5 was 1.6× higher in degenerated group compared with nondegenerated controls;	77
					CXCL6 was 1.3× higher in degenerated group compared with controls
2016	Weber et al.	LBP vs. control; DH vs. other Dx	80	Longitudinal – prospective	IL-6 1.4×higher in LBP than controls;	62
					MMP-1 1.56× higher in LBP than controls;
					IL-2 2× lower in LBP than controls;
					IL-4 1.5× higher in LBP than controls;
2016	Ye et al.	IVD degeneration vs. control	40	Cross-sectional – prospective	IL-18 increased with increased degeneration	76