Effect of DPP4 Inhibition on Vasoconstriction

What Was Tested

The trial (phase 4) is built around Neuropeptide Y.

It had four arms (groups): Sitagliptin then Placebo (other), Placebo then Sitagliptin (other), Sitagliptin then Placebo: Valsartan (placebo comparator) and Placebo then Sitagliptin: Valsartan (placebo comparator).

The registry classes the interventions as drug.

More on the Plan

Dipeptidyl peptidase IV (DPP4) inhibitors are routinely used for the treatment of type II diabetes mellitus (T2DM).

Since the prevalence of hypertension is 1.5-3 times greater in diabetics compared to sex-aged matched controls, the use of antihypertensives such as ACE inhibitors is also common in diabetics.

DPP4 is involved in the degradation of multiple vasoactive peptides, one of which is neuropeptide Y.

This peptide is thought to play a role in blood pressure regulation and sympathetic nervous system activation.

Who Took Part

Enrollment: 18 actual participants took part.

It was open to people of any sex aged from 18 years up to 55 years.

Healthy volunteers were not accepted; participants needed the condition being studied.

Examples of who could join: Postmenopausal status for at least 1 year, or. Status post-surgical sterilization, or. If of childbearing potential, utilization of some form of birth control and willingness to undergo β-HCG testing prior to drug treatment and on every study day.

The full record lists 6 inclusion and 25 exclusion criteria; among the exclusions: type 1 diabetes; use of anti-diabetic medications other than metformin; pregnancy. breast-feeding.

How the Study Was Run

It was run as a randomized, crossover and quadruple-blind study.

Because people in this Neuropeptide Y study were split into groups at random, differences between the groups are less likely to reflect who happened to join each one.

In the crossover set-up each of the participants took both Neuropeptide Y and the comparison in turn, acting as their own control.

Neither the participants nor the staff measuring them knew who was on Neuropeptide Y, so expectations could not easily colour the readings.

Those kept unaware of assignments: participant, care provider, investigator and outcomes assessor.

It started in 2015-12 with completion listed for 2017-06.

It ran at 1 site in United States.

Its stated primary purpose is basic science.

What Was Measured

Primary outcome: Forearm Blood Flow.

It also tracked 13 secondary outcomes, for example Arterial Norepinephrine, Venous Norepinephrine, NPY Metabolites, Insulin, GLP-1 and Glucose.

What This Means in Plain Language

Put simply, this is a phase 4, randomized trial of Neuropeptide Y in 18 people.

Its size is small, so on its own it can only give an early look.

The trial is marked completed; results are posted on the registry, and this page does not restate them.

More context: the Neuropeptide Y compound page, all human trials.