Impact of Intranasal Insulin on Sympathetic Activity and Cerebral Vasodilation

Novel Treatment for Brain Insulin Resistance and Hypoperfusion

Status

Suspended

Phases

Early Phase 1

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT05153395

Enrollment

Registered

2021-12-10

Start date

2021-12-01

Completion date

2027-06-30

Last updated

2025-12-19

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Autonomic Dysfunction, Healthy, Insulin Resistance, Obesity, Vasodilation

Brief summary

The purpose of this project is to examine the impact of increases in brain insulin on sympathetic nervous system activity, as well as peripheral and cerebral blood flow in humans.

Interventions

OTHERCarbon dioxide breathing

Hypercapnic (5% carbon dioxide) air will be administered before and after intra-nasal insulin exposure.

OTHERNeurovascular Coupling

Participants will be asked to repeatedly open and close their eyes. With eyes open, participants will focus on a visual image. This will be done before and after intra-nasal insulin exposure.

DRUGHuman insulin

Participants will be administered human insulin (160 IU) as a bolus using an intra-nasal device.

Study design

Allocation

NON_RANDOMIZED

Intervention model

PARALLEL

Primary purpose

BASIC_SCIENCE

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

18 Years to 45 Years

Healthy volunteers

Yes

Inclusion criteria

* healthy adult men and women; * 18-45 years of age; * BMI \>18 kg/m2; * non-pregnant/non-breastfeeding; * non-nicotine users;

Exclusion criteria

* taking any medications known to affect metabolic, respiratory, cardiovascular, and/or autonomic Self-reported history of: * hepatic, renal, pulmonary, cardiovascular, or neurological disease; * stroke or neurovascular disease; * bleeding/clotting disorders; * sleep apnea or other sleep disorders; * diabetes; * smoking; * history of alcoholism or substance abuse; * hypertension; * respiratory disease; * active cancer; * autoimmune disease.

Design outcomes

Primary

Measure	Time frame	Description
Amount of cerebral blood flow	Change from baseline at minute 15	Measured with trans-cranial Doppler ultrasound (cm/s) or arterial spin labeling (mL/100 g/min)

Secondary

Measure	Time frame	Description
Amount of muscle sympathetic nerve activity (MSNA)	Change from baseline at minute 15	MSNA burst incidence (bursts/100 heart beats)
Amount of leg blood flow	Change from baseline at minute 15	Measured with Doppler ultrasound (mL/min)

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 6, 2026