Intra-individual Variability and Circadian Rhythm of VEGF Levels and Interaction With Biomarkers

Intra-individual Variability and Circadian Rhythm of Systemic Vascular Endothelial Growth Factor (VEGF) Levels and Interaction With Biomarkers of Inflammation in Subjects With Normal Glucose Tolerance (NGT) and Patients With Type 2 Diabetes Without Diabetic Macular Edema (DME)

The study evaluates the intra-individual variability of VEGF levels over a period of 6 months as well as the circadian variation of VEGF levels, both under standardized conditions in patients with type 2 diabetes without DME and matched subjects with normal glucose tolerance (NGT). Secondary objectives of the study are to evaluate the relationship of individual VEGF-levels to biomarkers of inflammation, HbA1c and major cardiovascular risk factors.

Inclusion Criteria:

• Written informed consent
• Age equal to or between 50 and 80 years
• Subjects with normal glucose tolerance confirmed by glucose tolerance test (control group) or patients with type 2 diabetes: diabetes duration 5-25 years; HbA1c equal to or between 6.5 and 9% (diabetes group)
• Ability to understand and follow study-related instructions

Exclusion Criteria:

• DME
• hsCRP > 10 mg/dl
• Acute infections
• Acute or chronic inflammatory diseases
• Immune diseases
• Treatment with immune suppressive drugs
• Treatment with glucocorticoids
• Myocardial infarction and stroke within 1 year before inclusion
• Hemorrhage within the previous 5 years
• Surgeries within the previous 3 months
• Oncological diseases
• Women who are pregnant or breast-feeding