Expression patterns of E-cadherin, involucrin, and connexin gap junction proteins in the lining epithelia of inflamed gingiva

The structural integrity and functional differentiation of the lining epith elium were studied in relation to inflammatory changes associated with dest ructive periodontitis. In the different regions of lining epithelia from cl inically healthy gingiva and periodontitis, comparisons were made of the ex pression patterns of E-cadherin, which is critical in intercellular adhesio n; of proteins associated with gap junction communication channels; and of involucrin, which is a keg. marker of differentiation in stratified epithel ia, Filamentous actin (F-actin), which is important in cell structural inte grity, attachment, and migration, was also examined. Semiquantitative immun ohistochemical analysis revealed that in both clinically healthy gingiva an d lesions of advanced periodontitis, expression patterns of E-cadherin, inv olucrin, and connexins 26 and 43 were similar, with a statistically signifi cant reduction in staining intensity from the external oral epithelium, thr ough the gingival sulcus, to the junctional epithelium or pocket epithelium , respectively, Furthermore, there was a striking reduction in staining for E-cadherin, involucrin, and both connexins in the pathological lining epit helium of the periodontal pocket. These changes were associated with marked alterations of filamentous actin expression, collectively indicating profo und perturbation of the epithelial structure, The data reported support the concept that the ability of the pathological lining epithelium to function as an effective barrier against the ingress of microbial products into the tissues is severely compromised. Copyright (C), 2000 John Wiley & Sons, Lt d.