Serum levels of the proinflammatory cytokine interleukin-6 vary based on diagnoses in individuals with lumbar intervertebral disc diseases.

BACKGROUND: Many intervertebral disc diseases cause low back pain (LBP). Proinflammatory cytokines and matrix metalloproteinases (MMPs) participate in disc pathology. In this study, we examined levels of serum cytokines and MMPs in human subjects with diagnoses of disc herniation (DH), spinal stenosis (SS), or degenerative disc disease (DDD) relative to levels in control subjects. Comparison between subjects with DH and those with other diagnoses (Other Dx, grouped from SS and DDD) was performed to elaborate a pathological mechanism based on circulating cytokine levels. METHODS: Study participants were recruited from a spine neurosurgery practice (n = 80), a back pain management practice (n = 27), or a control cohort (n = 26). Serum samples were collected before treatment and were assayed by multiplex assays for levels of interleukin (IL)-1ß, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, interferon-γ, tumor necrosis factor-α, MMP-1, MMP-3, and MMP-9. Inflammatory and degradative mediator levels were compared for subjects with LBP and control subjects, by diagnosis and by treatment groups, controlling for effects of sex, age, and reported history of osteoarthritis. Spearman's correlation coefficient was used to examine relationships with age, body mass index (BMI), symptom duration, and smoking history. RESULTS: Serum levels of IL-6 were significantly higher in subjects with LBP compared with control subjects. Participants with LBP due to Other Dx had significantly higher levels of IL-6 than DH and controls. Serum levels of MMP-1 were significantly lower in LBP subjects, specifically those with DH, than in control subjects. Positive correlations were found between IL-6 levels and BMI, symptom duration, and age. MMP-1 levels were positively correlated with age. CONCLUSIONS: The findings of the present clinical study are the results of the first examination of circulating cytokine levels in DDD and SS and provide evidence for a more extensive role of IL-6 in disc diseases, where patients with DDD or SS have higher serum cytokine levels than those with DH or control subjects. These findings suggest that LBP subjects have low-grade systemic inflammation, and biochemical profiling of circulating cytokines may assist in refining personalized diagnoses of disc diseases.

Exploratory study for identifying systemic biomarkers that correlate with pain response in patients with intervertebral disc disorders.

Molecular events that drive disc damage and low back pain (LBP) may precede clinical manifestation of disease onset and can cause detrimental long-term effects such as disability. Biomarkers serve as objective molecular indicators of pathological processes. The goal of this study is to identify systemic biochemical factors as predictors of response to treatment of LBP with epidural steroid injection (ESI). Since inflammation plays a pivotal role in LBP, this pilot study investigates the effect of ESI on systemic levels of 48 inflammatory biochemical factors (cytokines, chemokines, and growth factors) and examines the relationship between biochemical factor levels and pain or disability in patients with disc herniation (DH), or other diagnoses (Other Dx) leading to low back pain, which included spinal stenosis (SS) and degenerative disc disease (DDD). Study participants (n = 16) were recruited from a back pain management practice. Pain numerical rating score (NRS), Oswestry Disability Index (ODI), and blood samples were collected pre- and at 7 to 10 days post-treatment. Blood samples were assayed for inflammatory mediators using commercial multiplex assays. Mediator levels were compared pre- and post-treatment to investigate the potential correlations between clinical and biochemical outcomes. Our results indicate that a single ESI significantly decreased systemic levels of SCGF-ß and IL-2. Improvement in pain in all subjects was correlated with changes in chemokines (MCP-1, MIG), hematopoietic progenitor factors (SCGF-ß), and factors that participate in angiogenesis/fibrosis (HGF), nociception (SCF, IFN-α2), and inflammation (IL-6, IL-10, IL-18, TRAIL). Levels of biochemical mediators varied based on diagnosis of LBP, and changes in pain responses and systemic mediators from pre- to post-treatment were dependent on the diagnosis cohort. In the DH cohort, levels of IL-17 and VEGF significantly decreased post-treatment. In the Other Dx cohort, levels of IL-2Rα, IL-3, and SCGF-ß significantly decreased post-treatment. In order to determine whether mediator changes were related to pain, correlations between change in pain scores and change in mediator levels were performed. Subjects with DH demonstrated a profile signature that implicated hematopoiesis factors (SCGF-ß, GM-CSF) in pain response, while subjects with Other Dx demonstrated a biomarker profile that implicated chemokines (MCP-1, MIG) and angiogenic factors (HGF, VEGF) in pain response. Our findings provide evidence that systemic biochemical factors in patients with LBP vary by diagnosis, and pain response to treatment is associated with a unique profile of biochemical responses in each diagnosis group. Future hypothesis-based studies with larger subject cohorts are warranted to confirm the findings of this pilot exploratory study.

Emerging trends in biological therapy for intervertebral disc degeneration.

Intervertebral disc disease is characterized by a series of deleterious changes in cellularity that lead to loss of extracellular matrix structure, altered biomechanical loading, and symptomatic pain. At present the "gold standard" of therapy is discectomy -- surgical removal of the diseased disc followed by fusion of the adjacent vertebral bodies. The procedure alleviates pain, but fusion limits range of motion and alters the mechanical loading at other spinal levels, hastening disease at previously unaffected sites. Biological therapeutics have the potential to repair damaged tissue by several means: (1) altering cell phenotype to regenerate matrix components, (2) augmenting tissue with reparative cells, (3) delivering bioactive materials to reestablish disc biomechanics and serve as a template for cell-based regeneration. Although research into biological treatments for disc degeneration has been ongoing for over a decade, few treatments have progressed to clinical testing and none are currently commercially available, primarily due to a limited understanding of disease etiology. Further work is needed to identify targets and interventional time points as disc degeneration progresses from early to later stages. This review focuses on emerging trends in biological treatments and identifies key obstacles to their clinical translation.

Passive immunotherapy for anthrax toxin mediated by an adenovirus expressing an anti-protective antigen single-chain antibody.

In the 2001 U.S. bioterror attacks, 33,000 individuals required postexposure prophylaxis, 18 subjects contracted anthrax (11 inhalation, 7 cutaneous), and despite optimal medical therapy, 5 deaths resulted. Rapid protection against anthrax is required in a bioterrorism scenario; this study describes an in vivo gene transfer-based therapy that uses a human adenovirus (Ad)-based vector (AdalphaPAscAb) encoding a single-chain antibody directed against protective antigen (PA), a critical component of Bacillus anthracis lethal toxin. Following AdalphaPAscAb administration to mice, anti-PA single-chain antibody and anti-PA neutralizing activity were detected in serum over a 2-week period. Substantial survival advantage from anthrax lethal toxin was conferred by AdalphaPAscAb following administration from 1 to 14 days prior to toxin challenge, compared to no survival associated with an Ad vector expressing a control single-chain antibody. Passive immunotherapy with an Ad-based vector may be a rapid, convenient approach for protecting a susceptible population against anthrax, including use as an adjunct to antibiotic therapy.