Evaluation of Oxidative Stress: Comparison Between Type 1 Diabetes Mellitus and Latent Autoimmune Diabetes in Adults

The aim of this observational study will be to evaluate the levels of the main oxidative stress markers in T1DM and LADA and to identify if there are some oxidative stress markers specific for the two diseases. Secondary objectives will be to evaluate if there is an association between oxidative stress markers and severity of the diseases.

Primary aim:

Verify whether biomarkers levels depend on the type of disease (T1DM vs LADA), while adjusting for patients' characteristics.

Secondary aims:

2.1) Verify whether biomarkers levels are associated with glycemic control (FPG, HbA1c, PPG).

2.2) In incident cases, to assess whether a decrease in HbA1c corresponds to a decrease in the biomarkers at 3 months from start of treatment within each disease.

2.3) Verify whether these biomarkers tend to form clusters, overall and by diagnosis.

After obtaining informed consent, the investigators will recruit 75 patients with T1DM and 75 with LADA with an age ≥ 18 years and ≤ 75 years, of both sexes. All patients will be selected among outpatients attending the Center of Diabetes and Metabolic Diseases of First Department of Internal Medicine, IRCCS Policlinico San Matteo Foundation. The study design will include one single visit where patients' medical history and blood samples will be collected. For incident cases, a follow-up visit at 3 months from the start of treatment will be scheduled to assess whether a decrease in HbA1c corresponds to a decrease in the biomarkers. For a comprehensive oxidative balance evaluation, the d-ROMs test will be carried out to evaluate the pro-oxidant status linked to one of the parameters related to the antioxidant potential (BAP test, OXY-Adsorbent test, -SHp test and anti-ROMs test). Parameters will be evaluated using Free Radical Elective Evaluator (FREE) Duo by Diacron International s.r.l. (Grosseto, ITALY), an integrated analytical system that permits any type of chemical-clinical analysis based on the principle of photometry. The investigators will also evaluate high sensitivity C-reactive protein (Hs-CRP), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA). To evaluate if there is an association between a worse stage of the diseases and some oxidative stress markers, the investigators will also evaluate glycated hemoglobin (HbA1c) fasting plasma glucose (FPG), post-prandial glucose (PPG). All plasmatic parameters will be determined after a 12-h overnight fast, with the exception of PPG, determined 2 hours after a standardized meal. Venous blood samples will be taken for all patients between 8 A.M. and 9 A.M. The investigators will use plasma obtained by addition of Na2-ethylenediaminetetraacetic acid (EDTA), 1 mg/ml, and centrifuged at 3000 g for 15 minutes at 4°C. Immediately after centrifugation, the plasma samples will be frozen and stored at -80 °C for no more than 3 months. All measurements will be analyzed by the Laboratory of Molecular Medicine, General Medicine 1, IRCCS Policlinico San Matteo Foundation with proven experience in the dosage of these markers. The investigators will study 10 biomarkers. The sample size calculation is based on feasibility. The investigators expect to enrol 75 patients with T1DM and 75 patients with LADA, of both sexes, aged ≥ 18 and ≤ 75 years.