Estudo transversal de proteômica salivar de crianças com Diabetes Mellitus Tipo 1

Abstract

Type 1 diabetes mellitus (DM1) is an autoimmune disease that leads to deficiency in insulin production, corresponding to the most prevalent disease in childhood, affecting children under 5 years of age. Saliva has been shown to be a diagnostic fluid for systemic diseases, although studies on saliva for the identification of biomarker proteins are still scarce. In this perspective, the present dissertation aimed to analyze the profile of the salivary proteome of children with and without type 1 diabetes mellitus (compensated and non-compensated) and their correlations with glycated hemoglobin (Hb A1c) and metabolic control. 64 children of both sexes, aged 2-10 years old, were selected, 32 of whom were included in the compensated and decompensated groups (DM1-C and DM1-NC, respectively) and 32 controls (C) matched for age and sex. Data collection occurred in a single moment with anamnesis and diabetes monitoring exams (fasting, postprandial glycemia and Hb A1c), saliva collection, dental clinic exam, dental treatment and subsequent analysis with laboratory flow measurement protocol, protein measurement using the Bradford method, SDS-PAGE and mass spectrometry to identify peptides and proteins. The data were tabulated in Excel and analyzed using SPSS, then, using parametric and non-parametric tests, a significance level of p≤0.05 was adopted. The results showed in the study population, children (30 girls and 34 boys) with a mean age of 7.28 ± 1.87 years, the mean Hb A1c in diabetic patients was 7.91% ± 1.35% (min- max 6.1% -10.3%), DM1-C (6.7% ± 0.34) and DM1-NC (9.1 ± 0.77). The mean salivary flow (mL / min) was 0.37 ± 0.2 (min-max. 0.02 and 1.02), while the mean salivary protein concentrations were 4.23 μg / μL ± 4.3 (min-max. -1.48 and 15.71). Normalized protein concentrations based on salivary flow were 1.9 μg / μL ± 0.9 (min-max. -0.99 and 14.14). Comparison between diabetics and control showed no significant difference between groups for the variables: protein concentrations (p = 0.41), age (p = 0.34), flow (p = 0.49), normalized protein concentration based on flow (p = 0.07), weight (p = 0.88), height (p = 0.36). There was a positive correlation of significance in the concentration of proteins in saliva with postprandial glucose (rho = 0.40; p = 0.048) and with age (rho = 0.32; p = 0.03). A total presence of 18 protein bands was observed, with no significant difference between the presence / absence of bands with the presence / absence of DM1 or DM1-C / DM1-NC. 8 Proteins were identified: cystatin-B, lysozyme C, cystatin-SN, cystatin-S, cystatin-SA, pancreatic amylase B, alpha-amylase 1, immunoglobulin heavy constant alpha 1. In conclusion, quantitative and qualitative associations and differences were observed between the total saliva of patients with and without DM1, in which the presence of certain bands of proteins associated with sex, breastfeeding and allergy can help in the identification of certain proteins and biomarker sources.