Immunohistochemical and ultrastructural features of gingival epithelium and lamina propria in young individuals with concomitant connective tissue dysplasia

Aim of study. The aim of this study was to identify pathogenetically meaningful immunohistochemical and morphological features in the gingival epithelium and lamina propria in patients suffering from concomitant connective tissue dysplasia (CTD).
Materials and methods. The material for histological and immunohistochemical (IHC) studies were gingival biopsies obtained with punch biopsy needles. In view of the clinical, instrumental, and dental examination data, the patients (n=60; age – 18-25) with intact periodontium were divided into two groups where the main group were individuals (n=30) with malocclusions and moderate to severe undifferentiated connective tissue dysplasia (UCTD), while the control group included individuals (n=30) with physiological occlusion and featuring no UCTD signs. The biopsy material was used for morphological examination, namely, staining with hematoxylin and eosin, polychrome toluidine blue, and Picro-Sirius Red Stain Kit; IHC reactions were performed with primary antibodies to Ki-67, p53, E-cadherin, VEGFR-3, and CD68. The distribution of Type I and Type III collagen was analyzed with polarized light microscopy. Morphometric measurements were performed on photographic images employing ImageJ 1.47i software.
Results. The data obtained through the study pointed at morphological changes involving the epithelium and lamina propria of the gingiva in individuals with intact periodontium and concomitant UCTD. In the main group – as compared to the control group – multi-vector dynamics of quantitative changes in the gingival structures was detected (by Me): a decrease in the number of fibroblasts (1.19 times, p≤0.05); lymphatic vessels with positive staining for VEGFR-3 (1.16 times, p≤0.05); the share of Ki-67+ epithelial cells (1.11 times, p≥0.05); the share of Ki-67+ fibroblasts (1.36 times, p≤0.05), as well as Type I/III collagen ratio (1.51 times, p≤0.05), with an increase in the number of labrocytes (1.65 times, p≤0.05); the share of p-53+ epithelial cells (1.45 times, p≤0.05), and the share of p-53+ fibroblasts (1.68 times, p≤0.05). No significant differences (p≤0.05) were identified between the number of CD68+ macrophages in the groups. The data obtained through the qualitative assessment of cell adhesion demonstrate a decrease (1.86-2.0 times; p≤0.05) in the number of patients with «moderate» staining for E-cadherin in the basal and spinous layers in the main group, which is indicative of a weakening intercellular interaction in the germinative layers of the gingival epithelium in individuals with UCTD.
Conclusion. Interpretation of the results of histological and IHC studies revealed dynamic changes in the quantitative composition of macrophages (CD68+), lymphatic vessels (VEGFR-3+), adipocytes, qualitative intercellular contacts, proliferative activity of epithelial cells and fibroblasts, as well as Type I/III collagen ratio, which expands scientific knowledge regarding the structural arrangement in the stratified squamous epithelium and lamina propria of the gingiva in patients with UCTD syndrome. A significant (p≤0.05) reduction affecting the proliferative activity of fibroblasts, the number of lymphatic vessels with positive staining for VEGFR-3, and the intensity of E-cadherin cell adhesion protein expression, combined with an increase in p53 protein expression as well as in the number of adipocytes, serve key links in the mechanism of reducing the total number of fibroblasts in the gingival epithelium and lamina propria, which stands behind the decrease in regenerative potential in individuals with UCTD.
Keywords: connective tissue dysplasia, immunohistochemical markers, morphology, expression level, E-cadherin, Type I and III collagen
Conflicts of interest. The author have no conflicts of interest to declare.
Funding. There was no funding for this study.