Characteristics of Cell Damage at the Division Stage and Nuclear Aberrations in the Buccal Epithelium Cytogram of Individuals with Impaired Carbohydrate Metabolism

Aim: To compare the frequency of cell damage at the division stage, apoptosis, and necrosis/nuclear destruction in the buccal epithelial cytogram of individuals with impaired carbohydrate metabolism. Materials and Methods: In this observational cross-sectional study, buccal epithelial cytograms were obtained from 52 patients with type 2 diabetes mellitus (T2DM), 26 patients with metabolic syndrome (MS) and impaired carbohydrate metabolism (prediabetes), and 27 patients with MS without impaired carbohydrate metabolism. The smears were stained with eosin-methylene blue followed by Romanowsky staining (azure-eosin solution). Venous blood samples were tested for fasting glucose, 2 h post-load glucose, and glycated hemoglobin (HbA1c, %). The frequency of cell damage per 1000 cells in the cytogram was expressed as the median and interquartile range. Between-group comparisons were performed with the non-parametric Kruskal–Wallis test; when differences were present, Dunn’s post hoc pairwise tests were applied. Spearman’s rank correlation coefficient was calculated to assess the relationship between the HbA1c level and the frequency of nuclear destruction parameters in buccal epithelial cells per 1000 cells. Results: The median frequency of nuclear vacuolization in the buccal epithelial cytogram of T2DM patients was 1.5-fold and 2.5-fold higher than in MS patients with prediabetes (p < 0.001) and in MS patients without impaired carbohydrate metabolism (p < 0.001), respectively. Binucleated cells were more frequent in the cytograms of MS patients with prediabetes than in those of MS patients without impaired carbohydrate metabolism (p = 0.008). Nuclear protrusions were observed more often in the buccal epithelium of T2DM patients than in that of MS patients without impaired carbohydrate metabolism (p = 0.015). Karyopyknosis was less frequent in T2DM patients than in MS patients without impaired carbohydrate metabolism (p = 0.006) and did not differ significantly from the values in MS patients with prediabetes (p = 0.363). Karyorrhexis in the buccal epithelial cytogram was 34-fold higher in T2DM patients (p < 0.001) and 6-fold higher in MS patients with prediabetes (p < 0.01) than in MS patients without impaired carbohydrate metabolism. Karyolysis was significantly more frequent in T2DM patients than in MS patients without impaired carbohydrate metabolism (p = 0.014) and did not differ significantly from the values in MS patients with prediabetes (p > 0.1). Conclusions: In patients with MS, T2DM and prediabetes were associated with a higher frequency of nuclear abnormalities and degenerative changes in buccal epithelial cells. Because oral hygiene and periodontal inflammation indices were also worse in these groups and no multivariable adjustment was performed, these associations cannot be attributed independently to hyperglycemia and should be regarded as hypothesis-generating. Buccal epithelial cytology may be considered a simple candidate, non-invasive complementary indicator of impaired carbohydrate metabolism that requires further validation, rather than a standalone diagnostic or screening tool; this preliminary observational study lacked a healthy (non-MS) control group and diagnostic accuracy analyses (ROC curves, sensitivity/specificity, cut-off values), which are needed before any clinical application.