Hypoglycemia
Conditions
Keywords
MRI
Brief summary
The purpose of this study is to investigate how the brain responds to low blood glucose in non-diabetic individuals. The ultimate goal is to understand the brain substrates of hypoglycemia unawareness, a condition that can occur in patients with type1 diabetes undergoing insulin treatment.In the present study, the investigators focus on differences between two groups of non-diabetic subjects: one group who experienced two episodes of hypoglycemia the day prior to the study (and supposedly developed some level of unawareness to hypoglycemia), and one group who did not. In this study, a 3 tesla MRI scanner is used to acquire brain images. The imaging system is identical to the ones used in hospitals.
Detailed description
Hypoglycemia, also called low blood glucose or low blood sugar, occurs when blood glucose drops below normal levels. When blood glucose starts to drop, the body reacts to this drop, trying to restore the blood glucose level. Symptoms of hypoglycemia are usually easily recognized. Hypoglycemia can be treated quickly and easily by eating or drinking a small amount of glucose-rich food. However some people with long history of diabetes can have an impaired response to hypoglycemia and therefore don't recognize the symptoms of hypoglycemia, condition called hypoglycemia unawareness. If not treated hypoglycemia can get worse and cause confusion, clumsiness, fainting etc. Currently, it is not fully understood which brain areas are involved in sensing the drop of glucose levels. Absence of such knowledge is a critical barrier to the design and monitoring of effective intervention strategies to avoid and/or reverse hypoglycemia unawareness. The purpose of this study is to investigate how the brain responds to low blood glucose in non-diabetic individuals. Specific focus is given to differences between two groups of non-diabetic subjects: one group who experienced two episodes of hypoglycemia the day prior to the study (and therefore supposedly developed some level of unawareness to hypoglycemia), and one group who did not.
Interventions
DRUGInsulin
In each clamp, a small intravenous catheter is placed in participant's arm for infusion of insulin together with potassium phosphate and glucose. Insulin is a hormone that body makes naturally and it causes blood sugar to decrease. Insulin (and glucose) will be infused in calculated doses to maintain blood sugar level in the target range of 95 mg/dl or 50 mg/dl depending on the clamp.
DRUGGlucose
Glucose is administered together with insulin and potassium phosphate during each clamp via the intravenous catheter. Glucose is a sugar and it is used to carefully regulate blood sugar level.
Potassium phosphate is administered together with glucose and insulin during each clamp via the intravenous catheter. Potassium is a salt-like substance that is present in the blood.
Sponsors
University of Minnesota
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
Participants will be included in the study, if they * are non-diabetic * are evaluated as not contraindicated (based on
Exclusion criteria
) * are age (within 5 years), gender, and body mass index (within 4 kg/m2) matched to patients with type 1 diabetes who have participated to a similar study which involved only the second part (day 2) of the current protocol.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change from baseline (i.e., normal glucose levels) functional connectivity, measured as a dimensionless correlation coefficient of MRI signals among brain areas, at hypoglycemia | Baseline and immediately as hypoglycemia starts | Functional connectivity will be measured with MRI at 3 Tesla |
| Change from baseline (i.e., normal glucose levels) cerebral blood flow, measured in ml/min/100g, at hypoglycemia | Baseline and immediately as hypoglycemia starts | Cerebral blood flow will be measured with MRI at 3 Tesla |
Countries
United States
Outcome results
None listed