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NCT Number: NCT04387422

Recurrent Hypoglycemia in Type 1 Diabetes (Aim 2)

This study will explore the cerebral mechanisms of impaired awareness of hypoglycemia (IAH) in type 1 diabetics following exposure to experimental recurrent hypoglycemia (HG). To induce IAH, patients with T1D identified to have normal awareness of hypoglycemia (NAH) will undergo three 2-hour long hypoglycemic clamps. Neurochemical profiles will be measured by high field MRS before and after induction of IAH. Subject glycemic variability and activity/sleep for 1 week before each study will be monitored as all factors have been shown to alter responses to HG.

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Key information

Conditions

Diabetes Mellitus, Type 1 Autoimmune Diseases Diabetes Mellitus Endocrine System Diseases Glucose Metabolism Disorders Immune System Diseases Metabolic Diseases Nutritional and Metabolic Diseases

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Minnesota

Minneapolis, Minnesota, 55455, United States

About this study

The long-term goal of this project is to identify how recurrent hypoglycemia (HG) leads to the clinical syndrome of impaired awareness of hypoglycemia (IAH) in type 1 diabetes (T1D).

This study will test the hypothesis that recurrent HG in T1D leads to an upregulation in brain glucose transport and alterations in glutamatergic and GABAergic tone. The investigators will use MRS methodology that permits evaluation of cerebral cortex and hypothalamus in the same session to simultaneously evaluate the cerebral correlates/mediators of impaired awareness and impaired counterregulatory hormone responses (CRR). High MR data quality and reproducibility will be ensured by using high field MR scanners and technical advances (automated voxel placement, real-time voxel position, frequency, shim updates). Continuous glucose monitoring and actigraphy will be used to chronicle glucose variability and activity/exercise/sleep in the weeks before each experiment to assess the impact of these variables on IAH.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Type 1 diabetes diagnosed on clinical or laboratory grounds
  • Diabetes duration 2 - 30 years
  • Hemoglobin A1C <8.5%

Exclusion criteria

  • Impaired awareness of hypoglycemia as determined by the Cox and Gold questionnaires
  • Pregnant or plan to become pregnant during the study period
  • Uncontrolled hypertension (blood pressure > 145/95 mmHg at screening)
  • Evidence of autonomic neuropathy (presence of orthostatic hypotension or history of gastroparesis)
  • Proliferative retinopathy
  • Impaired kidney function (GFR < 45)
  • History of myocardial infarction, stroke, seizures, neurosurgical procedures, major depression requiring hospitalization within the last 5 years, arrhythmias
  • Current substance abuse
  • Use of drugs that can alter glucose metabolism including but not limited to glucocorticoids and niacin, and excluding insulin and glucose lowering drugs used to treat diabetes, as determined by a clinician
  • Inability to undergo MRI scanning, including but not limited to unable to remain still in an MRI scanner for more than 30 minutes, claustrophobia, presence of paramagnetic substances or pacemakers in body, weight over 300 lbs
  • Unable to complete all study visits or procedures, as determined by the investigator

Treatment and study plan

Experimental hyperglycemia

Other

Experimental hyperglycemia with MRI

Primary outcomes

  1. Glucose kinetics during hyperglycemic clamps before and after induction of IAH

    Time frame: 240 Minutes

    A kinetic model of glucose transport through the blood-brain-barrier (BBB) via reversible symmetric Michaelis-Menten kinetics and irreversible utilization in brain tissue will be utilized. The kinetics of glucose transport into and utilization in the frontal cortex will be quantified using dynamic modeling to extract the Michaelis-Menten constants and the maximal rate for glucose transport and utilization. The ratio of maximal transport rate to cerebral metabolic rate of glucose will be estimated for the hypothalamus by steady-state modeling.

Secondary outcomes

  1. Antecedent glycemia concentration

    Time frame: 14 days

    Antecedent glycemia will be evaluated using continuous glucose monitors with particular attention to the percentage of time a participant is above, at, or below target of 80-180 mg/dl and to measures of glycemic variability.

  2. Antecedent physical activity - moderate to vigorous physical activity

    Time frame: 14 days

    Antecedent physical activity and sleep will be evaluated using the data collected by the ActiGraph Link monitors. Activity counts will be set at 15-second epochs and classified into sedentary, light, moderate, and vigorous categories based on Troiano et al. cut points. Participants' average minutes engaged in moderate to vigorous physical activity levels per day will be reported.

  3. Antecedent physical activity - light physical activity

    Time frame: 14 days

    Antecedent physical activity and sleep will be evaluated using the data collected by the ActiGraph Link monitors. Activity counts will be set at 15-second epochs and classified into sedentary, light, moderate, and vigorous categories based on Troiano et al. cut points. Participants' average minutes engaged in light physical activity per day will be reported.

  4. Antecedent physical activity - sedentary time

    Time frame: 14 days

    Antecedent physical activity and sleep will be evaluated using the data collected by the ActiGraph Link monitors. Activity counts will be set at 15-second epochs and classified into sedentary, light, moderate, and vigorous categories based on Troiano et al. cut points. Participants' average minutes engaged in sedentary time per day will be reported.

  5. Antecedent physical activity - energy expenditure

    Time frame: 14 days

    Antecedent physical activity and sleep will be evaluated using the data collected by the ActiGraph Link monitors. Activity counts will be set at 15-second epochs and classified into sedentary, light, moderate, and vigorous categories based on Troiano et al. cut points. Participants' average daily energy expenditure (kilocalories) will be reported.

  6. Antecedent physical activity - sleep quality

    Time frame: 14 days

    Antecedent physical activity and sleep will be evaluated using the data collected by the ActiGraph Link monitors. Activity counts will be set at 15-second epochs and classified into sedentary, light, moderate, and vigorous categories based on Troiano et al. cut points. Participants' average sleep quality will be reported.

Sponsors and collaborators

Lead sponsor

University of Minnesota

Other

Registry information

Official study title

Measurement of Glucose Homeostasis in Human Brain by NMR: Effect of Recurrent Hypoglycemia on Type 1 Diabetes (Aim 2)

Important dates

Study start
2020
Primary completion
2028
Study completion
2028
First posted
May 13, 2020
Registry last updated
Apr 8, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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