Effect of Weight Loss on Brain Insulin Sensitivity in Humans

University Hospital Tuebingen40 enrolled

Overview

Obesity if known to be associated with brain insulin resistance in humans. This condition has not only implication for the brain but also for whole-body energy homeostasis. Research in rodents indicates that weight loss is able to improve insulin sensitivity of the brain. The current project will test this hypothesis in humans. Therefore, brain insulin sensitivity will be assessed by fMRI in combination with intranasal insulin administration, using an established protocol. Furthermore, effects of daily administration of insulin nasal spray (versus placebo) over 8 weeks will be assessed as secondary (exploratory) variables.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

DOUBLE

Enrollment

Conditions

Insulin Resistance

Interventions

Eligibility

Sex: ALLMin age: 40 YearsMax age: 75 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * HbA1c \<6.5% * Age between 40 and 75 years * No intake of antidiabetic drugs or drugs for weight reduction * no steroid intake * Stable medication over 10 weeks before the start of the study Exclusion Criteria: * Persons who wear non-removable metal parts in or on the body. * Persons with reduced temperature sensitivity and / or increased sensitivity to heating of the body * Cardiovascular disease can not be ruled out, e.g. manifest coronary heart disease, heart failure greater than NYHA 2, previous heart attack, stroke condition * Persons with hearing impairment or increased sensitivity to loud noises * People with claustrophobia * Minors or non-consenting subjects are also excluded * Subjects with an operation less than 3 months * Simultaneous participation in other studies * Neurological and psychiatric disorders * Subjects with hemoglobin Hb \<11 g / dl * Hypersensitivity to any of the substances used

Outcomes

Primary Outcomes

brain insulin sensitivity

fMRI measurement will be performed before and after administration of 160 U of human insulin as nasal spray. Changes in regional activity will be quantified to assess regional brain insulin sensitivity.

Time frame: 30 minutes after administration of nasal insulin

Secondary Outcomes

Effect of daily administration of 160 U nasal insulin or placebo over 8 weeks on body weight.

Participants will receive nasal insulin or placebo in a double-blind randomized fashion. Before and after 8 weeks body weight will be recorded.

Time frame: 8 weeks

Effect of daily administration of 160 U nasal insulin or placebo over 8 weeks on glucose tolerance .

Participants will receive nasal insulin or placebo in a double-blind randomized fashion. Before and after 8 weeks glucose tolerance will be assessed using a 75 g oral glucose tolerance test.

Time frame: 8 weeks

Effect of daily administration of 160 U nasal insulin or placebo over 8 weeks on body composition .

Participants will receive nasal insulin or placebo in a double-blind randomized fashion. Before and after 8 weeks body composition will be addressed by whole-body MRI and liver MRS.

Time frame: 8 weeks

whole-body insulin sensitivity

Insulin sensitivity will be estimated from a frequent-sampling 75 g oral glucose tolerance test using the Matsuda formula.

Time frame: 2 hours

Glucose tolerance

a 75 g oral glucose tolerance test will be performed. Glucose tolerance will be defined by the American Diabetes Association criteria.

Time frame: 2 hours

Cognitive function

cognitive function will be addressed by neuropsychological testing.

Time frame: 1 hours

Effect of Weight Loss on Brain Insulin Sensitivity in Humans

Overview

Conditions

Interventions

Eligibility

Locations (1)

Outcomes

Primary Outcomes

Secondary Outcomes

Central Contacts