Clinical predictors of the honeymoon period and evaluation of miRNA expression in pediatric patients diagnosed with Type 1 diabetes mellitus

One of the most common endocrine disorders in the pediatric patient group is diabetes mellitus. Diabetes mellitus (DM) is a group of carbohydrate metabolism disorder that result from insufficient insulin secretion or insulin action, leading to hyperglycemia due to glucose being unable to be used as an energy source and being overproduced due to gluconeogenesis and glycogenolysis. In pediatric patients, there is a phase called honeymoon period during the course of type 1 diyabetes mellitus (T1DM). During this period, patients' insulin requirements decrease and their metabolic parameters become more stable. The importance of this phase lies in the fact that patients experiencing the honeymoon period tend to have a more balanced long-term course of the disease and experience fewer diabetes-related complications. The aim of this study is to better understand the molecular biomarkers that could predict whether patients will enter this phase. The study included 40 newly diagnosed T1DM patients from the pediatric age group and 40 healthy control subjects matched for age and gender. At the beginning of the study, the biochemical and demographic data of the patients and the control group were recorded. Samples were collected from the patients with T1DM included in the study for biochemical, immunological, and molecular analyses at the time of diagnosis. At the beginning of the study, the levels of miRNA 23a-3p, miRNA 23b-3p, miRNA 24-3p, miRNA 27a-3p, miRNA 27b-3p, miRNA 3187-3p, miRNA 4723-5p, miRNA 103a-3p, and miRNA 375 were analyzed in the study and control groups. The patient group was followed up for 6 months after diagnosis and was called for outpatient clinic check-ups at 3 and 6 months. HbA1c, C-peptide, glucose, and miRNA level analyses were performed at the 3- and 6- month outpatient clinic check-ups. At the end of our study, no significant difference was found between the patient and control groups in terms of age, gender distribution, and auxological data. Twenty-three of the 40 patients (57.5%) entered the honeymoon period. No significant difference was found between patients who entered the honeymoon period and those who did not in terms of age, gender, auxological data, and antibody levels. When comparing the T1DM patient group with the control group, a significant difference was found in the expression levels of miRNA 24-3p and miRNA 27a-3p. miRNA 27a-3p expression was significantly higher in the T1DM group, while miRNA 24-3p expression was significantly higher in the control group. No significant difference was found in miRNA expression at diagnosis, 3 months, and 6 months between patients who entered remission and those who did not. In the T1DM patient group, there were significant changes in the time-dependent expression levels of miRNA 23a-3p, miRNA 24-3p, and miRNA 27a-3p during the 6-month follow-up period. The expression levels of miRNA 23a-3p and miRNA 24-3p gradually increased, while the expression level of miRNA 27a-3p gradually decreased. In conclusion, miRNA 24-3p expression was initially low in newly diagnosed T1DM patients and increased during the course of the disease, while miRNA 27a-3p expression was initially high and decreased during the course of the disease. Based on these results, we can conclude that miRNA 24-3p and miRNA 27a-3p play different regulatory roles in the early and advanced stages of diabetes.