Characterization of circulating leukocytes and correlation of leukocyte subsets with metabolic parameters 1 and 5 years after diabetes diagnosis.

AIMS: Infiltration of pancreatic islets with different leukocyte subtypes likely contributes to deterioration of glycemia in diabetes mellitus. Different subsets of leukocytes have been previously associated with type 1 or type 2 diabetes. This study aimed at examining these subsets at different stages of diabetes progression and possible relationships with metabolic parameters. METHODS: A total of 206 patients, 76 with type 1 and 130 with type 2 diabetes, were studied within the first year of diabetes diagnosis. In addition, 31 patients with type 1 and 73 with type 2 diabetes were examined at 5 years after diagnosis. Whole body insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamps; insulin secretion by glucagon stimulation tests and white blood cells were analyzed by flow cytometry. RESULTS: The percentage of peripheral CD8+ cells was 15% lower in patients with type 1 diabetes at 5 years than in patients at diabetes onset and correlated positively with fasting glycemia, total cholesterol and high-sensitive C-reactive protein (hsCRP) (all r > 0.37, p < 0.05), but not with insulin secretion. Patients with type 2 diabetes had 7% higher percentages of CD4+ cells after 5 years than those at diagnosis. CD4+ cells correlated with hsCRP (r = 0.36, p < 0.05), whereas CD8+ cytotoxic T-cells did not correlate with any metabolic parameter. CONCLUSION: CD8+ T-cells associate with worse glycemia, lipidemia and inflammation after 5 years of type 1 diabetes, whereas CD4+ T-cells associate with increased inflammation after 5 years upon onset of type 2 diabetes.

Advanced glycation end products strongly activate platelets.

BACKGROUND: Diabetes mellitus is characterized by hyperglycemia that plays an important role in the pathogenesis of diabetic complications including cardiovascular diseases. Moreover, hyperglycemia induces increased generation of advanced glycation end products (AGEs). The activation of platelets is associated with the development of cardiovascular diseases. AIM OF THE STUDY: The question whether AGEs acutely induce platelet activation as a response to exogenous stimulus is addressed. MATERIALS AND METHODS: The effect of AGEs derived from food and human serum being purified by lysozyme affinity chromatography was examined by incubating in vitro freshly isolated blood platelets from fasted subjects at various concentrations and different time points. Platelet activation, determined as expression of surface markers CD62 and CD63, and the presence of the receptor for AGEs (RAGE) in platelet membranes was measured by flow cytometric analysis using specific antibodies. RESULTS: Incubation with food-derived as well as serum-derived AGEs stimulated significantly the expression of CD62 up to 7.1-fold and CD63 up to 2.2-fold at the platelet surface membrane as a function of concentration and time. Incubation with thrombin or AGEs significantly increased RAGE expression twofold at the platelet surface membrane. CONCLUSIONS: The increase in surface activation marker and RAGE expression in platelets, resulting from concentrations of AGEs that occur in vivo after a meal or a drink as a source of exogenous AGEs, points to signaling mechanisms for food AGEs that could favor the precipitation of acute postprandial ischemic events.