CD36 in Nutrient Delivery and Its Dysfunction

Role of CD36 in Nutrient Delivery and Its Dysfunction in African Americans

This proposal will test the hypothesis that chronic treatment with sildenafil with and without the use of nitric oxide substrate, L-arginine, protects against fatty acid induced impairment of endothelial function, improves insulin-stimulated microvascular recruitment, insulin sensitivity and glucose uptake in CD36 rs3211938 G-allele carriers.

Study Overview

• Status: Completed
• Conditions: Insulin Resistance; Endothelial Dysfunction
• Intervention / Treatment: Drug: Sildenafil Citrate in G allele carrier; Drug: Sildenafil Citrate in non G allele carrier

Detailed Description

Subjects carrying the G-allele of CD36 coding SNP rs3211938 that results in 50% reduction of CD36 levels in ~25% of African Americans have endothelial dysfunction. Endothelial dysfunction results in impairment of insulin's vascular actions and eventually reduced insulin sensitivity. Insulin induces microvascular recruitment via stimulation of nitric oxide(NO)-cGMP pathway, which facilitates nutrient flux, e.g., glucose to skeletal muscle. Elevated fatty acids impair insulin-stimulated microvascular recruitment and reduce insulin sensitivity. Chronic treatment with sildenafil increases vascularity and muscle glucose uptake in high fat fed mice. In humans, Drs. Shibao (PI) recently reported that a 3-month treatment with sildenafil improves insulin sensitivity in patients with impaired glucose tolerance. More relevant to this project, endothelial dysfunction improved after 4-week treatment with sildenafil in G-allele carriers. This proposal will test the hypothesis that chronic treatment with sildenafil with and without the use of NO substrate, L-arginine, protects against fatty acids induced impairment of endothelial function, improves insulin-stimulated microvascular.

The protocol design was changed to single arm design.

• Study Type: Interventional
• Enrollment (Actual): 26
• Phase: Phase 2; Phase 1

Contacts and Locations

Study Locations

• United States
  • Tennessee
    • Nashville, Tennessee, United States, 37232
      • Vanderbilt University Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 50 years (ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion criteria

• African American men and women.
• Age 18-50 years
• BMI 25-40 kg/m2

Exclusion criteria:

• Diabetes type 1 or type 2, as defined by a FPG > 126 mg/dL a two-hour plasma glucose > 200 mg/dL, or the use of anti-diabetic medication
• Pulmonary hypertension
• Use of a PDE5 inhibitor for erectile dysfunction
• Pregnancy or breast-feeding. Women of child-bearing potential will be required to have undergone tubal ligation or to be using an oral contraceptive or barrier methods of birth control.
• Cardiovascular disease such as myocardial infarction, presence of angina pectoris, significant arrhythmia, congestive heart failure (left ventricular hypertrophy acceptable), deep vein thrombosis, pulmonary embolism, second or third degree heart block, mitral valve stenosis, aortic stenosis or hypertrophic cardiomyopathy
• History of serious neurologic disease such as cerebral hemorrhage, stroke, or transient ischemic attack
• History or presence of immunological or hematological disorders
• Any underlying or acute disease requiring regular medication which could possibly pose a threat to the subject or make implementation of the protocol or interpretation of the study results difficult
• Treatment with chronic systemic glucocorticoid therapy (more than 7 consecutive days in 1 month)
• History of alcohol or drug abuse
• Mental conditions rendering a subject unable to understand the nature, scope and possible consequences of the study
• Inability to comply with the protocol, e.g., uncooperative attitude, inability to return for follow-up visits, unlikelihood of completing the study, and investigator discretion

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: NA
• Interventional Model: SINGLE_GROUP
• Masking: NONE

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Sildenafil citrate; Sildenafil citrate 20 mg three times a day	Drug: Sildenafil Citrate in G allele carrier; chronic use of phosphodiesterase 5 inhibitor in G allele carrier; Other Names: viagra, revatio,; Drug: Sildenafil Citrate in non G allele carrier; chronic use of phosphodiesterase 5 inhibitor in Non G allele carrier; Other Names: viagra, revatio

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Microvascular Blood Volume (MBV) During Insulin Infusion	Insulin induces microvascular recruitment. Changes in MBV during Insulin infusion signifies insulin sensitivity. MBV is measured in the forearm brachioradialis muscle with contrast enhanced ultrasonography during minutes 120-150 of a hyperinsulinaemic euglycaemic (HIE) clamp (insulin infusion rate up to 80 mU/m2.min-1 ). In the last 30 minutes, L-arginine was infused (10 mg/kg/min for 30 minutes) and ultrasound measurements were repeated upon infusion completion (approximately minute 180).	Baseline to end of procedure (approximately 180 minutes)
Change in Microvascular Blood Volume (MBV) During Insulin Infusion After 4 Weeks of Sildenafil Treatment in Both Groups	Chronic treatment with sildenafil increases vascularity and muscle glucose uptake. Changes in MBV during Insulin infusion signifies insulin sensitivity . Insulin sensitivity was tested after 4 weeks of treatment with Sildenafil in both groups. Subjects receive IV infusion of 20% Intralipid (45ml/h) and heparin (200 units/hr). MBV is measured in the forearm brachioradialis muscle with contrast enhanced ultrasonography during minutes 120-150 of a HIE clamp (insulin infusion rate up to 80 mU/m2.min-1 ) In the last 30 minutes, L-arginine was infused (10 mg/kg/min for 30 minutes) and ultrasound measurements were repeated upon infusion completion (approximately minute 180).	Baseline to 4 weeks

Collaborators and Investigators

• Sponsor: Vanderbilt University Medical Center
• Collaborators: Washington University School of Medicine

Study record dates

Study Major Dates

• Study Start (ACTUAL): January 1, 2017
• Primary Completion (ACTUAL): July 1, 2021
• Study Completion (ACTUAL): July 31, 2021

Study Registration Dates

• First Submitted: January 3, 2017
• First Submitted That Met QC Criteria: January 4, 2017
• First Posted (ESTIMATE): January 6, 2017

Study Record Updates

• Last Update Posted (ACTUAL): November 30, 2022
• Last Update Submitted That Met QC Criteria: November 6, 2022
• Last Verified: November 1, 2022

More Information

Terms related to this study

• Keywords: Endothelial dysfunction; African Americans; CD36
• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Hyperinsulinism; Insulin Resistance; Molecular Mechanisms of Pharmacological Action; Vasodilator Agents; Urological Agents; Enzyme Inhibitors; Anticoagulants; Phosphodiesterase Inhibitors; Chelating Agents; Sequestering Agents; Phosphodiesterase 5 Inhibitors; Calcium Chelating Agents; Sildenafil Citrate; Citric Acid; Sodium Citrate
• Other Study ID Numbers: 160955

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No