Inflammatory cytokines in saliva: early signs of metabolic disorders in chronic kidney disease. A controlled cross-sectional study.

OBJECTIVE

The aim of this study was to evaluate correlations between levels of cytokines in secreted stimulated saliva in patients with chronic kidney disease (CKD) and hyposalivation.

STUDY DESIGN

Seventy patients with clearance <20 mL/min/1.73 m(2) were evaluated; 40 were predialysis, 21 hemodialysis, and 9 peritoneal dialysis, and they were matched with 70 control subjects. Salivary flow rate was measured and submandibular/sublingual saliva collected. Analyses were performed for whole protein content using a protein assay, and levels of tumor necrosis factor (TNF) α, interleukin (IL) 1β, γ-interferon (γ-INF), IL-6, IL-8, IL-10, monocyte chemotactic protein (MCP) 1, and soluble intercellular adhesion molecule (sICAM) 1, by using Luminex technology.

RESULTS

Patients with CKD had lower (P = .03) stimulated salivary secretion rate and higher salivary whole protein concentration (P = .002) than control subjects. Concentrations of IL-8 (P = .03) and MCP-1 (P = .002) were decreased and TNF-α/IL-10 (P = .05) and IL-8/IL10 (P = .03) ratios were decreased in CKD patients. CKD patients with low secretion levels of stimulated saliva expressed decreased levels of TNF-α (P = .04), IL-1β (P = .02), γ-INF (P = .03), IL-6 (P = .003), IL-8 (P = .005), MCP-1 (P = .006), and sICAM-1 (P = .02).

CONCLUSIONS

Salivary cytokines and secretion rates are significantly decreased in CKD patients. Further research is necessary to understand operating mechanisms and clinical implications of the down-regulation of inflammatory markers in saliva.