Porphyromonas gingivalis lipopolysaccharide and glycated serum albumin increase the production of several pro-inflammatory molecules in human gingival fibroblasts via NFκB.

Objective: Diabetes increases the incidence/severity of periodontal diseases by inducing a chronic inflammation, driven by accumulation of AGEs (advanced glycation end products). We tested whether glycated human serum albumin (G-HSA, a form of AGE), representing a diabetic state, augments the pro-inflammatory response of human gingival fibroblasts (hGFs) to a bacterial challenge (Porphyromonas gingivalis Lipopolysaccharide (LPS)).

Methods: Primary hGFs were incubated with LPS (0.5-5 μg/mL) and G-HSA (50-200 μg/mL) and the production and gene expression of IL-1β, IL-6, IL-8, MMP-1, MCP-1, and TNFα were analyzed by Magnetic Luminex Assay and real-time PCR, respectively. Non-glycated serum albumin (HSA) served as negative control. Cytotoxicity of the 2 agents was tested with an XTT assay. NFκB activation (p65 phosphorylation) was measured with an ELISA.

Results: P. gingivalis LPS and G-HSA were not toxic to hGFs and increased the amount of MMP-1, MCP-1, IL-6, and IL-8, (but not TNFα and IL-1β) secreted into the medium at 24 h. Control HSA had no effect. Many LPS/G-HSA combinations displayed a synergistic stimulation of these molecules. Both agents increased mRNA levels of these 4 molecules at 6 h, 12 h or both (IL-6). NFκB activation at 6 h was caused by both agents with a possible synergism at the higher concentrations.

Conclusions: glycated albumin augments the pro-inflammatory response of human gingival fibroblasts to P. gingivalis LPS. Thus, AGE accumulation in diabetes could aggravate periodontal inflammation by augmenting the pro-inflammatory response of host GFs to P. gingivalis, a well-recognized periopathogenic bacteria.