Neutrophils and Periodontitis in Diabetes

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DESCRIPTION: Diabetes has now reached epidemic status in the United States, affects 6.5% of the general population, and continues to increase at a very alarming rate. Periodontal disease is referred to as the sixth complication of diabetes. There is a reciprocal relationship between diabetes and periodontal disease where each condition exacerbates the other. We have recently observed that neutrophils and monocytes from diabetic patients contain elevated diacylglycerides (DAG), enhanced activity of protein kinase C (PKC), and can release significantly more superoxide and/or tumor necrosis factor-alpha than cells from healthy individuals. Superoxide, cytokines and matrix metalloproteinases play a significant role in the destruction of periodontal tissues in diabetes. Importantly, certain endogenous, anti-inflammatory lipids that result from transcellular metabolism of arachidonic and eicosapentaenoic acid (lipoxins, resolvins) were found to be highly effective in inhibiting superoxide release from diabetic neutrophils and blocking periodontal disease in a rabbit model. In this proposal, we will: 1) determine the molecular mechanisms responsible for alterations in DAG and PKC in diabetic patients; 2) uncover the biochemical basis for priming of neutrophils/monocytes in diabetes, and determine if this priming is prevented when patients are brought under glycemic control and/or treated for periodontal disease; 3) determine the signal transduction pathways by which advanced glycation end products (AGE) prime neutrophils; and 4) determine if certain endogenous anti-inflammatory lipid mediators (e.g., lipoxins, resolvins) can limit the inflammatory response in diabetes by blocking the enhanced functional responses of neutrophils and monocytes from these patients. Techniques of modern biochemistry, immunology and cell biology will be employed in these investigations. These studies have the potential of leading to better methods of treating periodontal disease and perhaps other complications of diabetes.