Hypoglycemia and Autonomic Nervous System Function-B

Phase 4

• Conditions: Hypoglycemia; Healthy
• Interventions: Drug: Placebo; Drug: Spironolactone; Other: Hypoglycemic Hyperinsulinemic Clamp; Other: Euglycemic Hyperinsulinemic Clamp

• Registration Number: NCT03429946
• Lead Sponsor: Brigham and Women's Hospital

Brief Summary

This study tests the hypothesis that, compared to prior normal blood sugar, prior low blood sugar impairs cardiovascular autonomic function. The proposed studies will also test the hypothesis that the effects of prior low blood sugar on cardiovascular autonomic function are blocked by administration of a mineralocorticoid receptor antagonist.

Detailed Description

This study involves three interventions, which are performed in random order. Each intervention involves a 3-day inpatient visit. There is a space of 1-3 months between interventions. The three interventions are: 1) placebo with a hyperinsulinemic euglycemic clamp, 2) spironolactone with a hyperinsulinemic hypoglycemic clamp, or 3) placebo with a hyperinsulinemic hypoglycemic clamp. Each 3-day inpatient visit includes the following. On Day 1, autonomic testing is performed. Autonomic testing includes assessment of Baroreflex Sensitivity (BRS). BRS is assessed using the Modified Oxford procedure, which involves sequential administration of nitroprusside and phenylephrine while measuring heart rate and beat to beat blood pressure with a finapress and assessing Muscle Sympathetic Nerve Activity (MSNA). MSNA is measured using microelectrodes placed near the peroneal nerve. On Day 2, hyperinsulinemic clamps are performed with pre-treatment with either placebo or spironolactone. Modified Oxford Procedures are performed prior to and during each clamp on Day 2. On Day 3, the autonomic testing performed on Day 1 is repeated..

Study Timeline

• Study Start: 2013-07-17
• Study First Submitted: 2018-01-30
• Study First Submitted QC: 2018-02-09
• Study First Posted: 2018-02-12
• Status Verified: 2022-07
• Last Update Submitted: 2022-07-18
• Last Update Posted: 2022-07-20
• Primary Completion: 2024-01-04
• Study Completion: 2024-01-04

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 28

Inclusion Criteria

• Healthy volunteers
• Males and females age 18 to 55 years

Exclusion Criteria

• Pregnancy
• Lactation
• Clinically evident coronary artery, cerebrovascular, or peripheral vascular disease, or presence of systemic illness that might affect autonomic function. Such illnesses include diabetes mellitus, congestive heart failure, hypertension, renal, pulmonary, hepatic disease, anemia, malignancies, untreated thyroid disease, and alcoholism.
• Current major depressive illness
• In all subjects, any individuals on oral, injected, inhaled or topical corticosteroids within the last year or oral contraceptives within the past 3 months will be excluded.
• Use of medications other than thyroxine
• Known hypersensitivity to nitroglycerin, nitroprusside and/or phenylephrine.
• Blood pressure > 140/90 mmHg
• Creatinine > 1.5 mg/dL
• Serum potassium >5.2 mmol/L
• Estimated GFR < 50 mL/min
• Use of Viagra, Cialis, and similar drugs within 72 hours of admission.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Hypoglycemia and Spironolactone	Hypoglycemic Hyperinsulinemic Clamp	Participants undergo two 120-minute hypoglycemic hyperinsulinemic clamp procedures (50 mg/dL) - an AM clamp from about 9 am to 11 am and a PM clamp from 1 pm to 3 pm on Day 2 of a 3-Day study visit. Participants receive two doses of 100 mg of spironolactone - one dose 12 hours and one dose 3 hours before the first clamp starts. Modified Oxford Procedure is performed in duplicate at six time points - on Day 1, before the AM hyperinsulinemic clamp, during the AM hyperinsulinemic clamp, before the PM hyperinsulinemic clamp, during the PM hyperinsulinemic clamp, and on Day 3. The Modified Oxford procedure is performed to calculate baroreflex sensitivity.
Hypoglycemia and Placebo	Placebo	Participants undergo two 120-minute hypoglycemic hyperinsulinemic clamp procedures (50 mg/dL) - an AM clamp from about 9 am to 11 am and a PM clamp from 1 pm to 3 pm on Day 2 of a 3-Day study visit. Participants receive two doses of placebo - one dose 12 hours and one dose 3 hours before the first clamp starts. Modified Oxford Procedure is performed in duplicate at six time points - on Day 1, before the AM hyperinsulinemic clamp, during the AM hyperinsulinemic clamp, before the PM hyperinsulinemic clamp, during the PM hyperinsulinemic clamp, and on Day 3. The Modified Oxford procedure is performed to calculate baroreflex sensitivity.
Hypoglycemia and Placebo	Hypoglycemic Hyperinsulinemic Clamp	Participants undergo two 120-minute hypoglycemic hyperinsulinemic clamp procedures (50 mg/dL) - an AM clamp from about 9 am to 11 am and a PM clamp from 1 pm to 3 pm on Day 2 of a 3-Day study visit. Participants receive two doses of placebo - one dose 12 hours and one dose 3 hours before the first clamp starts. Modified Oxford Procedure is performed in duplicate at six time points - on Day 1, before the AM hyperinsulinemic clamp, during the AM hyperinsulinemic clamp, before the PM hyperinsulinemic clamp, during the PM hyperinsulinemic clamp, and on Day 3. The Modified Oxford procedure is performed to calculate baroreflex sensitivity.
Euglycemia and Placebo	Placebo	Participants undergo two 120-minute euglycemic hyperinsulinemic clamp procedures (90 mg/dL) - an AM clamp from about 9 am to 11 am and a PM clamp from 1 pm to 3 pm on Day 2 of a 3-Day study visit. Participants receive two doses of placebo - one dose 12 hours and one dose 3 hours before the first clamp starts. Modified Oxford Procedure is performed in duplicate at six time points - on Day 1, before the AM hyperinsulinemic clamp, during the AM hyperinsulinemic clamp, before the PM hyperinsulinemic clamp, during the PM hyperinsulinemic clamp, and on Day 3. The Modified Oxford procedure is performed to calculate baroreflex sensitivity.
Euglycemia and Placebo	Euglycemic Hyperinsulinemic Clamp	Participants undergo two 120-minute euglycemic hyperinsulinemic clamp procedures (90 mg/dL) - an AM clamp from about 9 am to 11 am and a PM clamp from 1 pm to 3 pm on Day 2 of a 3-Day study visit. Participants receive two doses of placebo - one dose 12 hours and one dose 3 hours before the first clamp starts. Modified Oxford Procedure is performed in duplicate at six time points - on Day 1, before the AM hyperinsulinemic clamp, during the AM hyperinsulinemic clamp, before the PM hyperinsulinemic clamp, during the PM hyperinsulinemic clamp, and on Day 3. The Modified Oxford procedure is performed to calculate baroreflex sensitivity.
Hypoglycemia and Spironolactone	Spironolactone	Participants undergo two 120-minute hypoglycemic hyperinsulinemic clamp procedures (50 mg/dL) - an AM clamp from about 9 am to 11 am and a PM clamp from 1 pm to 3 pm on Day 2 of a 3-Day study visit. Participants receive two doses of 100 mg of spironolactone - one dose 12 hours and one dose 3 hours before the first clamp starts. Modified Oxford Procedure is performed in duplicate at six time points - on Day 1, before the AM hyperinsulinemic clamp, during the AM hyperinsulinemic clamp, before the PM hyperinsulinemic clamp, during the PM hyperinsulinemic clamp, and on Day 3. The Modified Oxford procedure is performed to calculate baroreflex sensitivity.

Primary Outcome Measures

Name	Time	Method
Baroreflex Sensitivity assessed on Day 3	Baroreflex sensitivity is assessed on the 3rd day of each treatment (i.e. about 16 hours after completion of the hyperinsulinemic clamp)	Comparison of Day 3 baroreflex sensitivity (milliseconds/mm Hg) assessed during Hypoglycemic hyperinsulinemic clamp + Placebo treatment as compared to Hypoglycemic hyperinsulinemic clamp + Spironolactone treatment.

Secondary Outcome Measures

Name	Time	Method
Muscle sympathetic nerve activity assessed on Day 3	Muscle sympathetic nerve activity is assessed on the 3rd day of each treatment (i.e. about 16 hours after completion of the hyperinsulinemic clamp)	Comparison of Day 3 muscle sympathetic nerve activity (bursts/min) assessed during hypoglycemic hyperinsulinemic clamp + placebo treatment as compared to hypoglycemic hyperinsulinemic clamp + spironolactone treatment.

Trial Locations

Locations (2)

Beth Israel Deaconess Medical Center; 🇺🇸 Boston, Massachusetts, United States

Brigham and Women's Hospital; 🇺🇸 Boston, Massachusetts, United States