Protease Inhibitors and Iron-Binding Proteins in Gingival Crevicular Fluid Related to Periodontal Disease Status

Adonogianaki, Evagelia (1992) Protease Inhibitors and Iron-Binding Proteins in Gingival Crevicular Fluid Related to Periodontal Disease Status. PhD thesis, University of Glasgow.

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Little research has been conducted into the role of protease inhibitors and iron-binding proteins in periodontal diseases, despite their possible implication in the modulation of the local inflammatory process. This thesis aimed to investigate the major protease inhibitors alpha2-macroglobulin (alpha2-M) and al-antitrypsin (alpha1-AT) and the iron-bindings proteins transferrin (TF) and lactoferrin (LF) in gingival crevicular fluid (GCF), in relation to periodontal disease status. Preliminary experiments were performed to establish new or modify existing enzyme linked immunosorbent assays (ELISA) for the assessment of these proteins in GCF. The simultaneous quantification of alpha2-M, alphal-AT, TF and LF in the same GCF sample was the ultimate objective. Initial attempts resulted in the establishment of two competitive ELISAs for the assessment of alpha2-M and TF in GCF. In an effort to improve detectability limits, the establishment of sandwich ELISAs for the detection of these proteins and, in addition, of alpha1-AT, LF and albumin (Alb) was achieved. Application of the sandwich ELISA methodology resulted in an approximately 10 fold decrease in the detectability limits compared to the competitive ELISAs. Consequently, the assessment of all five proteins in the same GCF sample was possible in later studies. The clinical studies conducted in this thesis include cross-sectional studies on gingival crevicular washings (GCWs) and GCF and longitudinal studies on GCF. GCF samples were obtained using paper strips for 30s and GCF volume was assessed using the Periotron 6000. LF is contained specifically and in abundance in neutrophils (PMNs) but not in other leucocytes and only in trace amounts in serum. PMNs are widely implicated in the pathogenesis of destructive periodontal diseases. The aim of the cross-sectional study on GCWs was, therefore, to examine whether LF in the crevice could act as a marker of crevicular polymorphonuclear leucocytes (PMN). A positive and significant association was obtained indicating that LF has potential as a PMN marker in the gingival crevice. The aim of the cross-sectional studies on GCF was to test the ability of GCF protease inhibitors (alpha2-M, alpha1-AT) and iron-binding proteins (TF, LF) to distinguish between healthy, gingivitis and periodontitis sites. The absolute amounts (ng/30s) of each protein were significantly higher at diseased (gingivitis and periodontitis) when compared to healthy sites. However, gingivitis could not be differentiated from periodontitis sites. When results were expressed as concentrations (ng/alphal GCF), the predominately serum derived alpha2-M, alpha1-AT and TF demonstrated an increase in diseased (gingivitis and periodontitis sites) compared to healthy sites whereas the PMN derived LF demonstrated a decrease in its concentration in diseased sites. However, only the changes in GCF alpha2-M concentration were statistically significant depicting the higher degree of variability that was observed when results were expressed as concentrations. The aim of the experimental gingivitis study was to establish the dynamics of GCF protease inhibitors and iron- binding proteins during experimentally induced gingivitis. This would provide information on the effect of gingival inflammation on the levels of these proteins in the crevice. alpha2-M, alpha1-AT and TF revealed a very similar pattern during the experimental gingivitis trial, reflecting their common origin in GCF. Their levels increased significantly from baseline. This was attributed to increased permeability of the subepithelial vasculature and is supported by the simultaneous rise in GCF volume. In addition, local production of these proteins by resident cells of the periodontium could also be implicated. Vascular permeability was maintained for at least one week after the end of the experimental gingivitis period and this contributed to increased levels of these proteins in the crevice one week after the reinstitution of oral hygiene. The PMN derived LF demonstrated a different overall picture rising significantly during the experimental gingivitis trial but dropping rapidly to almost baseline levels after the reinstitution of oral hygiene measures and when chemotactic stimuli for PMNs were removed. The final clinical study involved a three month duration longitudinal trial of periodontitis patients on maintenance care. The aim of this study was to investigate whether incipient periodontal disease breakdown could be associated with changes in GCF protease inhibitor or iron-binding protein levels. In addition, the potential of clinical indices to act as predictors/indicators of significant attachment level change was investigated. (Abstract shortened by ProQuest.).

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Adviser: D F Kinane
Keywords: Medicine, Dentistry
Date of Award: 1992
Depositing User: Enlighten Team
Unique ID: glathesis:1992-75844
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 19 Nov 2019 17:44
Last Modified: 19 Nov 2019 17:44

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