Conditions: Type 2 Diabetes
Keywords: Type 2 Diabetes, DPP-4 inhibitors, renal sodium excretion
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 36
Healthy volunteers: no

Brief summary:
Background: Dedicated renal hemodynamic and renal function studies are lacking for DPP-4 inhibitors in patients with Type 2 diabetes; accordingly little is known regarding the mechanisms mediating the renal effects of DPP-4 inhibitors in humans.

Objectives: To evaluate the effect of DPP-4 inhibition acutely (single dose) and following short-term therapy (28 days) on renal sodium handling and renal hemodynamics and function in patients with type 2 diabetes and systolic hypertension.

Design: double-blind, randomized, placebo-controlled trial, Phase IV.

Patient population: 32 patients with Type 2 diabetes, HbA1c (6.5%-9%), with systolic blood pressure ranging from 120-160 mmHg.

Intervention: subjects will be randomized (1:1) to either sitagliptin (100 mg daily) or to placebo (1 tablet daily) for 28 days.

Endpoints: Fractional excretion of sodium, renal function, and renal hemodynamics.

Detailed description:
Background: DPP-4 inhibition improves glycemic control, modestly reduces blood pressure and may also reduce albuminuria in patients with Type 2 diabetes; effects which occur without significantly modifying heart rate or body weight. While preclinical studies have demonstrated that DPP-4 inhibition acutely increases urinary sodium excretion in addition to other favorable renal effects (anti-inflammatory, anti-proteinuric), few studies have examined the renal effects of DPP-4 inhibition either acutely or following short-term therapy in humans with type 2 diabetes. Considering the world-wide prevalence of Type 2 diabetes and the increasing use of DPP-4 inhibitors amongst patients, it is important to ascertain potential non-glycemic effects of DPP-4 inhibitors including those within the kidney.

Study Objectives: To determine effect(s) of DPP-4 inhibition on tubular sodium handling, renal hemodynamics, and renal function.

Study Design: double-blind, randomized, placebo-controlled trial, Phase IV.

Study Patients: 32 patients with Type 2 Diabetes and Systolic Hypertension (SBP 120-160 mmHg).

Endpoints: Fractional excretion of sodium, renal function (measured GFR), renal hemodynamics (effective renal plasma flow, filtration fraction, renal blood flow, renal vascular resistance), systemic hemodynamics (non-invasive cardiac monitoring), plasma neurohormones, urinary vasoactive mediators, markers of free radical stress.

Arms:
arm 1: sitagliptin (DPP-4 inhibitor) oral tablet (100 mg); Januvia; administered once daily for 28 days arm 2: placebo (no medicinal ingredients) oral tablet (100 mg); administered once daily for 28 days

Interventions: intervention 1: Sitaglitpin intervention 2: Placebo
Intervention descriptions: intervention 1: Oral DPP-4 inhibitor, 100 mg tablet administered once daily for 28 days intervention 2: Oral tablet (no medicinal ingredients) administered once daily for 28 days

Protocol document: