Differences in Endothelial Function Amongst Sitagliptin and Liraglutide Users

Conditions

Liraglutide — DRUG
Liraglutide is available if pre-filled pens (6 mg/ml) as a solution for injection (Victoza®). One ml of solution contains 6 mg of Liraglutide (human glucagon-like peptide-1 analogue produced by recombinant DNA technology in Saccharomyces cerevisiae). One pre-filled pen contains 18 mg Liraglutide in 3 ml.
Sitagliptin — DRUG
Sitagliptin is available in 100 mg film-coated tablets (Januvia®). Each tablet contains sitagliptin phosphate monohydrate, equivalent to 100 mg sitagliptin.

Differences in endothelial function amongst Sitagliptin and Liraglutide Users. A randomized, open-label, parallel-group and active controlled trial

Experimental: Liraglutide
Liraglutide will be administered once a day by subcutaneous injection (under the skin) in the abdomen, thigh, or upper arm. It will be given independently of meals and preferably at the same each day. The starting dose will be 0.6 mg. After one week, the dose will be increased to 1.2 mg, and then it will be increased to 1.8 mg one week later to achieve better control of blood glucose. When Liraglutide is added to existing treatment containing metformin, as it is our scenario, the dose of metformin does not have to be changed.
Active Comparator: Sitagliptin
Sitagliptin will be administered once daily at a 100 mg dose. When Sitagliptin is used in combination with metformin, as it is our scenario, the dose of metformin should be maintained. If a dose of Sitagliptin is missed, it should be taken as soon as the patient remembers. A double dose should not be taken on the same day. Sitagliptin will be used daily during the study period of 12 weeks.

Assess the effects on endothelial function of a three month treatment with Liraglutide compared to Sitagliptin. [ Time Frame: 3months ]