ACTA ENDOCRINOLOGICA (BUC)

Objective. This study aimed to evaluate the utility of C-peptide levels in the differentiation of monogenic forms of diabetes from type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) in clinical practice. Subjects and Methods. A total of 104 patients aged >16 who visited the Dicle University’s Faculty of Medicine between April 2011 and December 2020 and were diagnosed with monogenic diabetes by genetic analysis or with T1DM and T2DM were randomly selected for retrospective evaluation. The C-peptide levels of these patients at the time of diagnosis of diabetes were compared. Results. Of the 104 patients, 24 (23%) were diagnosed with maturity-onset diabetes of the young (MODY), 40 (38.5%) with T1DM, and 40 (38.5%) with T2DM. Median C-peptide levels (ng/mL) (interquartile range) were 1.78 (1.24–2.88) in MODY group, 0.86 (0.34– 1.22) in T1DM group, and 2.38 (1.58–4.27) in T2DM group. Conclusions. There was a difference in C-peptide levels between MODY and T1DM groups but not between MODY and T2DM groups. As per clinical evaluations, although C-peptide levels of patients with MODY are similar to those of patients with T2DM patients, the possibility of C-peptide levels being similar to those required for T1DM diagnosis should also be considered.

Background. Insulin resistance is routinely measured by homeostasis model assessment of insulin resistance (HOMA-IR).Positron emission tomography of 18F-fluorodeoxyglucose combined with computed tomography (18F-FDG PET/CT) is a valuable assessment tool for patients with cancer or staging tumors. 18F-FDG PET/CT imaging can also be utilised to detect the metabolic activity of glucose in the adipose tissue, liver and muscles. The aim of this study was to determine insulin sensitivity in the liver, muscle visceral adipose and subcutaneous adipose tissue separately via18F-FDG PET/CT. Materials and method. Sixty three adult patients who underwent whole body 18F-FDG PET/CT scanning for clinical purposes (diagnosis or staging of cancer) between July and August of 2016 were included in the study. Patients were divided into two groups according to their BMI (Group 1: BMI<25kg/m2, Group 2: BMI>25kg/ m2). HOMA-IR,fasting glucose,insulin, triglycerides, total cholesterol, HDL levels were measured. We calculated SUV as the tissue activity of the ROI (MBq/g)/(injected dose [MBq]/ body weight [g]) on PET images and measured the maximum SUVs (SUVmax) of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT),liver and rectus muscle ROIs (2 cm). SUV corrected by blood glucose level (SUVgluc) was calculated as SUVmax×blood glucose level/100. Student-t test, Chi-square test and Pearson correlation test were used for statistical analysis. Results. Mean glucose,insulin,HOMA-IR levels of the group-2 were statistically higher than of group-1. Muscle SUVmax and liver SUVmax of group-1 were statistically higher than of group-2. Muscle SUVgluc of group-1 was statistically higher than of group-2. HOMA-IR was negatively correlated with both SUVmax(r=-0.340, p=0.01) and muscle SUVmax(r=-0.373, p=0.005) Conclusion. 18F-FDG PET/CT has shown that the muscle tissue maximum FDG uptake was lower in the insulin resistance group. Therefore, 18-FDG PET/CT could be a valuable tool for diagnosing insulin resistance.