ABSTRACT
High-mobility group box-1 (HMGB1) protein acts as a transcription factor in the nucleus and also as a pro-inflammatory cytokine when released into extracellular fluids. The presence of higher levels of HMGB1 is reported in the gingival crevicular fluid from periodontal patients. Since the proliferation of bacteria within the periodontal pocket is closely involved in the exacerbation of periodontal disease, it is hypothesized that the periodontal pocket causes the release of HMGB1. Immunohistochemical staining of inflamed gingiva revealed that HMGB1 is exclusively dislocated from the nucleus to the cytoplasm in the pocket epithelium, whereas it is mainly present in the nucleus in the gingival epithelium. Butyric acid, an extracellular metabolite from periodontopathic bacteria populating the periodontal pocket, induced the passive release of HMGB1 as a result of eliciting necrosis in the human gingival epithelial cell line. Thus, the periodontal epithelium may provide a unique pathological setting for HMGB1 release by bacterial insult.
Subject(s)
Butyric Acid/pharmacology , Gingival Crevicular Fluid/chemistry , HMGB1 Protein/metabolism , Periodontal Pocket/metabolism , Virulence Factors/metabolism , Adult , Aged , Case-Control Studies , Cell Line , Epithelial Cells/drug effects , Epithelial Cells/metabolism , Female , Gingiva/cytology , HMGB1 Protein/analysis , Humans , Male , Middle Aged , Necrosis/metabolism , Periodontal Pocket/microbiology , Periodontal Pocket/pathology , Protein Transport , Reactive Oxygen Species/metabolism , Virulence Factors/analysisABSTRACT
OBJECTIVE: To evaluate the effects of acute loading of protein from different sources on the glomerular filtration rate. RESEARCH DESIGN AND METHODS: A total of 6 healthy volunteer subjects and 6 diabetic patients with normoalbuminuria were studied before and after ingestion on separate days of tuna fish containing 0.7 g/kg body wt of protein, boiled egg white containing the same amount of protein as the tuna fish, or boiled egg white containing 1.4 g/kg body wt of protein. Furthermore, to study the possible role of prostaglandins and amino acids in the response of GFR to protein loading, urinary excretion of prostaglandins, and plasma levels of amino acids were measured during these tests. RESULTS: In normal subjects, the GFR rose significantly (P < 0.01) after ingestion of tuna fish. No significant differences were found between GFR before and after ingestion of the different amounts of egg white. The GFRs of the diabetic patients after ingestion of each of the meals were similar to the responses in healthy volunteers. Plasma levels of Gly and Ala (amino acids known to induce glomerular hyperfiltration) were higher after ingestion of tuna fish than after administration of egg white in all subjects. No differences were found in the plasma concentrations of any amino acids except Gly and Ala after loads of tuna fish and egg white containing 1.4 g/kg of protein. Urinary 6-keto-PGF1a excretion increased significantly (P < 0.01) after tuna fish loading, but did not change after egg white challenge. CONCLUSIONS: These findings could be explained either by differences in renal vasodilatory prostaglandin secretion or by increased plasma levels of Gly and Ala, which were increased only after ingestion of tuna fish. Thus, egg white has renal effects on GFR different from those of tuna fish, independent of the quantity of protein ingested.
