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Completed

NCT Number: NCT01354964

Effect of Vitamin D Repletion on Insulin Resistance and Systemic Inflammation

The purpose of this research is to study the effects of Vitamin D supplementation on the body's response to insulin (a hormone that controls blood sugar), on inflammation, and on specific cells and processes in fat tissue.

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Key information

Conditions

Insulin Resistance Glucose Metabolism Disorders Hyperinsulinism Metabolic Diseases Nutritional and Metabolic Diseases

Age range

21 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Albert Einstein College of Medicine

The Bronx, New York, 10461, United States

About this study

Over the last several years, studies have shown that low vitamin D levels may increase risk of developing Type 2 Diabetes. The investigators will administer vitamin D3 (cholecalciferol) to non-diabetic, insulin resistant subjects with vitamin D deficiency (total vitamin D levels <20 ng/ml) to increase the level of vitamin D3. The investigators will study the effects of increased Vitamin D on insulin action, adipose tissue inflammation, and on certain cells and processes in fat tissue.

Investigators will study participants with a procedure called a "pancreatic clamp" study. During the clamp procedure, glucose (a sugar) and insulin (a hormone produced in the pancreas that regulates the amount of glucose in the blood) are infused with an intravenous catheter, and blood samples are collected periodically throughout the procedure to measure blood sugar levels and the levels of several hormones that are found in the body and are related to glucose metabolism. Adipose tissue inflammation will be measured using the following inflammatory markers: IL-6, PAI-1, TNF-alpha, and iNOS.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Serum 25(OH)D<20ng/ml
  • Insulin Resistant based on HOMA-IR score of >3
  • Able and willing to provide informed consent
  • BMI 20-35

Exclusion criteria

  • HIV/AIDS
  • History of any cancer
  • Sarcoidosis
  • Alcohol or substance abuse
  • Cushing's syndrome
  • Primary hyperparathyroidism
  • Nephrolithiasis
  • Pregnancy or breastfeeding
  • Regular visits to a tanning salon
  • Hypercalcemia or hypocalcemia
  • Untreated or uncontrolled hypertension
  • Any chronic illness requiring medication, other than arthritis, hypertension and hyperlipidemia

Treatment and study plan

Vitamin D

Drug

Other names: Vitamin D3 (cholecalciferol)

Placebo

Drug

Primary outcomes

  1. Percent Change in Hepatic Insulin Sensitivity

    Time frame: 2nd clamp visit (after up to 3 months) and 3rd clamp visit (after up to 6 months)

    Endogenous glucose production (EGP) was assessed at each study visit to evaluate hepatic insulin sensitivity. Percent change between the EGP at baseline and second visit (after treatment for up to 3 months with Vitamin D to reach a target level of ≥30 ng/ml), and baseline and third visits (after treatment for up to 6 months with Vitamin D in order to reach a target level of ≥50 ng/ml) will be calculated.

Secondary outcomes

  1. Percent Change in Peripheral Glucose Uptake

    Time frame: 2nd clamp visit (up to 3 months) and 3rd clamp visit (up to 6 months)

    The rate of glucose uptake to determine peripheral insulin sensitivity was measured using the rate of disappearance (Rd) of glucose at each study visit. Percent change between the Rd at baseline and second visit (after treatment with Vitamin D for up to 3 months to target level of ≥30 ng/ml), and baseline and third visits (after treatment with Vitamin D for up to 6 months to target level of ≥50 ng/ml) will be calculated.

  2. Evaluated Expression of Pro-inflammatory Gene TNF-α

    Time frame: 2nd clamp visit (up to 3 months) and 3rd clamp visit (up to 6 months)

    Adipose tissue macrophages will be isolated from subcutaneous abdominal adipose tissue, and will be quantified by fluorescence activated cell sorting (FACS) analysis. TNF-α gene expression will be examined by real-time (rt-PCR) and will provide a measure of macrophage activation at baseline, at 2nd study visit (after treatment with Vitamin D to a goal level of ≥30 ng/ml), and at 3rd study visit (goal Vitamin D level of ≥50 ng/ml). The mRNA copy number is then compared with a reference gene copy number (5 commonly used house keeping genes [HKGs]) as a ratio, which is a measure of relative gene expression.

  3. Evaluated Expression of Pro-inflammatory Gene IL-6

    Time frame: 2nd clamp visit (up to 3 months) and 3rd clamp visit (up to 6 months)

    Adipose tissue macrophages will be isolated from subcutaneous abdominal adipose tissue, and will be quantified by fluorescence activated cell sorting (FACS) analysis. IL-6 gene expression will be examined by real-time (rt-PCR) and will provide a measure of macrophage activation at baseline, at 2nd study visit (after treatment with Vitamin D to a goal level of ≥30 ng/ml), and at 3rd study visit (goal Vitamin D level of ≥50 ng/ml). The mRNA copy number is then compared with a reference gene copy number (5 commonly used house keeping genes [HKGs]) as a ratio, which is a measure of relative gene expression.

  4. Evaluated Expression of Pro-inflammatory Gene iNOS

    Time frame: 2nd clamp visit (up to 3 months) and 3rd clamp visit (up to 6 months)

    Adipose tissue macrophages will be isolated from subcutaneous abdominal adipose tissue, and will be quantified by fluorescence activated cell sorting (FACS) analysis. iNOS gene expression will be examined by real-time (rt-PCR) and will provide a measure of macrophage activation at baseline, at 2nd study visit (after treatment with Vitamin D to a goal level of ≥30 ng/ml), and at 3rd study visit (goal Vitamin D level of ≥50 ng/ml). The mRNA copy number is then compared with a reference gene copy number (5 commonly used house keeping genes [HKGs]) as a ratio, which is a measure of relative gene expression.

  5. Evaluated Expression of Pro-inflammatory Gene PAI-1

    Time frame: 2nd clamp visit (up to 3 months) and 3rd clamp visit (up to 6 months)

    Adipose tissue macrophages will be isolated from subcutaneous abdominal adipose tissue, and will be quantified by fluorescence activated cell sorting (FACS) analysis. PAI-1 gene expression will be examined by real-time (rt-PCR) and will provide a measure of macrophage activation at baseline, at 2nd study visit (after treatment with Vitamin D to a goal level of ≥30 ng/ml), and at 3rd study visit (goal Vitamin D level of ≥50 ng/ml). The mRNA copy number is then compared with a reference gene copy number (5 commonly used house keeping genes [HKGs]) as a ratio, which is a measure of relative gene expression.

Sponsors and collaborators

Lead sponsor

Albert Einstein College of Medicine

Other

Collaborators

  • National Center for Research Resources (NCRR)

Registry information

Important dates

Study start
2009
Primary completion
2015
Study completion
2015
First posted
May 17, 2011
Registry last updated
Nov 2, 2020

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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