Effect of Vitamin D Repletion on Insulin Resistance and Systemic Inflammation
Study Overview
Status
Status
Conditions
Conditions
Intervention / Treatment
Intervention / Treatment
Detailed Description
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.
Study Type
Study Type
Enrollment (Actual)
Enrollment
Phase
Phase
- Phase 2
Contacts and Locations
Study Locations
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New York
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Bronx, New York, United States, 10461
- Albert Einstein College of Medicine
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Participation Criteria
Eligibility Criteria
Eligibility Criteria
Ages Eligible for Study
Accepts Healthy Volunteers
Genders Eligible for Study
Description
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
Study Plan
How is the study designed?
Design Details
- Primary Purpose: Treatment
- Allocation: Randomized
- Interventional Model: Parallel Assignment
- Masking: Double
Number of Arms
Arms and Interventions
Participant Group / ArmParticipant Group / Arm |
Intervention / TreatmentIntervention / Treatment |
|---|---|
|
Experimental: Vitamin D
Participants received weekly oral vitamin D drops using a weight-based calculated dosage for up to six months.
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Other Names:
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Placebo Comparator: Placebo
Participants received weekly oral placebo drops (similar in taste and appearance to vitamin D) for up to six months.
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What is the study measuring?
Primary Outcome Measures
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
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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)
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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.
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2nd clamp visit (after up to 3 months) and 3rd clamp visit (after up to 6 months)
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Secondary Outcome Measures
Secondary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
|
Percent Change in Peripheral Glucose Uptake
Time Frame: 2nd clamp visit (up to 3 months) and 3rd clamp visit (up to 6 months)
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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.
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2nd clamp visit (up to 3 months) and 3rd clamp visit (up to 6 months)
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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)
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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.
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2nd clamp visit (up to 3 months) and 3rd clamp visit (up to 6 months)
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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)
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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.
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2nd clamp visit (up to 3 months) and 3rd clamp visit (up to 6 months)
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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.
|
2nd clamp visit (up to 3 months) and 3rd clamp visit (up to 6 months)
|
|
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.
|
2nd clamp visit (up to 3 months) and 3rd clamp visit (up to 6 months)
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Collaborators and Investigators
Sponsor
Sponsor
Collaborators
Collaborators
Investigators
Investigators
- Principal Investigator: Meredith A Hawkins, M.D., M.S., Albert Einstein College of Medicine
Study record dates
Study Major Dates
Study Start (Actual)
Study Start
Primary Completion (Actual)
Primary Completion
Study Completion (Actual)
Study Completion
Study Registration Dates
First Submitted
First Submitted
First Submitted That Met QC Criteria
First Submitted That Met QC Criteria
First Posted (Estimate)
First Posted
Study Record Updates
Last Update Posted (Actual)
Last Update Posted
Last Update Submitted That Met QC Criteria
Last Update Submitted That Met QC Criteria
Last Verified
Last Verified
More Information
Terms related to this study
Additional Relevant MeSH Terms
Other Study ID Numbers
Other Study ID Numbers
- 2008-225
- 5K23RR023335-02 (U.S. NIH Grant/Contract)
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
Studies a U.S. FDA-regulated device product
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