Microvascular reactivity and oxidative stress after standard breakfast in patients with recently diagnosed type 2 diabetes
Eva Horova, Martin Prazny & Jan Skrha
Aim of the study: The aim of the study was to compare skin microvascular reactivity (MVR) with oxidative stress and metabolic parameters at fasting status and postprandially in patients with recently diagnosed type 2 diabetes.
Methods: Twenty patients with type 2 diabetes (mean age 58±6 years, HbA1C 4.8±0.5%, diabetes duration 2.3±1.3 years, metformin treatment only) were included in the study. Blood samples were taken before and after 60, 120 and 180 min after standard breakfast. MVR was measured by the laser Doppler flowmetry during post-occlusive (PORH) and thermal hyperemia (TH) before and after 60 and 180 min. Glycemia, insulinemia and β-hydroxybutyrate (BHB) concentration were evaluated and malonyldialdehyde (MDA) and conjugated dienes (CD) were used for the estimation of oxidative stress.
Results: Blood glucose increased from baseline with maximum after 60 min and consequently decreased down to baseline level after 180 min (baseline, 60, 120, 180 min: 6.9±0.6 8.0±1.6 7.6±1.2 6.2±0.8 mmol/l, P<0.01). Insulinemia increased significantly (39±16 142±82 106±63 55±39 mIU/l, P<0.01) while BHB decreased (0.24±0.16 0.16±0.06 0.15±0.07 0.16±0.06 mmol/l, P<0.01). MDA concentration was significantly lower after 120 min than at baseline (3.02±0.48 vs 2.80±0.40 μmol/l, P<0.05). Changes of several parameters of MVR were detected: maximal perfusion during PORH decreased after 180 min compared to baseline (235±66 vs 198±53 PU, P<0.01) as well as maximal perfusion during TH compared in the same times (113±53 vs 145±71 PU, P<0.05). Significant relations between MVR and metabolic parameters was found.
Conclusions: Significant metabolic changes were observed postprandially in patient with early stage of type 2 diabetes. MVR was probably mostly influenced by vasodilatory effect of insulin. Moreover, MVR may also be modulated by oxidative stress. The relationship between MVR and insulinemia may imply that the B-cell dysfunction can consequently lead to microvascular dysfunction through the effect of insulin.