Trial to Assess the Influence of 4 Weeks' Treatment With Linagliptin as Compared to Glimepiride and Placebo on Endothelial Function in Patients With Type 2 Diabetes Using FMD (Flow-Mediated Vasodilation)

Inclusion criteria

• Type 2 diabetic male and female patients according to the following criteria:

Based upon a complete medical history and clinical laboratory tests

• Age >= 18 and Age <= 65 years
• Body mass index >= 25 <= 35 kg/m2
• HbA1c <= 7.5%
• Treatment with metformin (=1500 mg daily) for <= 3 months
• Signed and dated written informed consent prior to admission to the study in accordance with GCP and the local legislation.

For female patients of childbearing potential:

• Use of acceptable method of contraception (Pearl-Index <1).

Exclusion criteria

• Treatment with any glucose-lowering drug except for metformin within prior 3 months.
• Any finding of the medical examination (including blood pressure, pulse rate and electrocardiogram) deviating from normal and of clinical relevance.
• Any evidence of a clinically relevant acute concomitant disease
• History of cardiovascular disease (e.g. coronary artery disease history of acute myocard infarction or stroke, peripheral vascular disease).
• History of major diabetic complications (e.g. nephropathy, retinopathy)
• Gastrointestinal, hepatic, renal, respiratory, cardiovascular, immunological or hormonal disorders (except: hypertension treated with angiotensin receptor blocker or angiotensin-converting-enzyme inhibitors, hyperlipidemia with statin therapy, thyroid hormone replacement therapy, all stable for at least three months prior to screening).
• Surgery of the gastrointestinal tract (except appendectomy).
• Diseases of the central nervous system (such as epilepsy) or psychiatric disorders or neurological disorders.
• History of relevant orthostatic hypotension, fainting spells or blackouts.
• Chronic or relevant acute infections.
• History of relevant allergy/hypersensitivity (including allergy to drug or its excipients).
• Intake of drugs with a long half-life (> 24 hours) within at least one month or less than 10 half-lives of the respective drug prior to administration or during the trial.
• Participation in another trial with an investigational drug within one month prior to administration or during the trial.
• Smoker (>= 1 cigarettes or >= 1 cigars or >= 1 pipes/day).
• Alcohol abuse (more than 60 g/day).
• Drug abuse.
• Blood donation (more than 100 mL within four weeks prior to administration or during the trial).
• Excessive physical activities (within one week prior to administration or during the trial).
• Any laboratory value outside the reference range that is of clinical relevance.