Effects of Oral Glucosamine on Insulin and Blood Vessel Activity in Normal and Obese People
|The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.|
|ClinicalTrials.gov Identifier: NCT00065377|
Recruitment Status : Completed
First Posted : July 22, 2003
Last Update Posted : June 26, 2006
|First Submitted Date ICMJE||July 21, 2003|
|First Posted Date ICMJE||July 22, 2003|
|Last Update Posted Date||June 26, 2006|
|Study Start Date ICMJE||July 2003|
|Primary Completion Date||Not Provided|
|Current Primary Outcome Measures ICMJE||Not Provided|
|Original Primary Outcome Measures ICMJE||Not Provided|
|Current Secondary Outcome Measures ICMJE||Not Provided|
|Original Secondary Outcome Measures ICMJE||Not Provided|
|Current Other Pre-specified Outcome Measures||Not Provided|
|Original Other Pre-specified Outcome Measures||Not Provided|
|Brief Title ICMJE||Effects of Oral Glucosamine on Insulin and Blood Vessel Activity in Normal and Obese People|
|Official Title ICMJE||An Exploratory Study of the Effects of Oral Glucosamine Administration on Insulin Sensitivity and Capillary Recruitment in Normal and Obese Subjects|
This study will examine whether glucosamine affects the way the body responds to insulin. Insulin is a hormone that causes the body to use glucose (sugar). Insulin does not work as well in overweight people, causing a condition called insulin resistance. Insulin also increases the flow of blood into muscle by opening inactive blood vessels. This study will test whether glucosamine, a nutritional supplement that many people take to treat arthritis, can cause or worsen insulin resistance or change how blood vessels react to insulin in normal weight and overweight people.
Healthy normal weight and overweight volunteers between 21 and 65 years of age may be eligible for this study. Candidates will be screened with a brief physical examination, medical history, and blood and urine tests. After screening, participants will have three additional outpatient clinic visits for the following procedures:
Visits 2 and 3
For these visits, the glucose clamp test and blood flow measurements are repeated. Visit 2 is scheduled at the end of the first 6-week treatment period, and Visit 3 is scheduled at the end of the second 6-week treatment period.
|Detailed Description||Glucosamine is a popular over-the-counter nutritional supplement that many people use for the treatment of osteoarthritis. Intravenous administration of glucosamine to animals or humans causes significant metabolic insulin resistance and vascular endothelial dysfunction. Moreover, experiments with various cell lines have implicated elevated glucosamine levels in the development of insulin resistance. However, there are no published studies examining the potential effects of oral glucosamine administration to modulate insulin sensitivity or capillary recruitment in humans. This is a significant concern because insulin resistance and vascular dysfunction contribute importantly to major public health problems including diabetes, obesity, hypertension, and cardiovascular diseases. Normal healthy volunteers and obese insulin resistant subjects will be enrolled in a randomized double-blind, placebo-controlled, crossover study to evaluate the effects of oral glucosamine to modulate insulin sensitivity and insulin-stimulated capillary recruitment. The reference standard hyperinsulinemic isoglycemic glucose clamp technique will be used to assess insulin sensitivity before treatment, after placebo or oral glucosamine (500 mg p.o. TID for 6 weeks), and after completion of the crossover. In addition, insulin-stimulated capillary recruitment will be measured at the same time as the glucose clamp studies by using the ultrasound microbubble contrast technique to assess blood flow in the brachial artery and capillary recruitment in forearm skeletal muscle in response to hyperinsulinemia. Finally, plasma glucosamine levels will be measured just prior to each glucose clamp study using an HPLC method. The results of this study will determine if oral glucosamine administration causes significant insulin resistance and impairment in insulin-stimulated capillary recruitment in healthy volunteers or worsens insulin resistance and capillary recruitment in obese subjects. In addition, our study will provide important information about how plasma glucosamine levels change with commonly used oral doses of glucosamine.|
|Study Type ICMJE||Interventional|
|Study Phase ICMJE||Phase 1|
|Study Design ICMJE||Primary Purpose: Treatment|
|Intervention ICMJE||Drug: Glucosamine Hydrochloride|
|Study Arms ICMJE||Not Provided|
* Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
|Recruitment Status ICMJE||Completed|
|Original Enrollment ICMJE||Same as current|
|Study Completion Date ICMJE||June 2006|
|Primary Completion Date||Not Provided|
|Eligibility Criteria ICMJE||
Males or females in good general health with no significant underlying illnesses, on no medication, between the ages of 21-65 years of age with HbA1C less than 6.5, fasting blood glucose less than 100 mg/dl, blood pressure less than 130/85, and BMI between 20-26 kg/m(2). Subjects should have never smoked tobacco or not smoked within the previous 2 years.
Males or females in good general health with no significant underlying illnesses, on no medication, between the ages of 21-65 years of age with HbA1C less than 6.5, fasting blood glucose less than 110 mg/dl, blood pressure less than 130/85, and BMI between 30-40 kg/m(2).
Subjects will be excluded if they have diabetes, hypertension, pregnancy, liver disease, pulmonary disease, renal insufficiency, coronary heart disease, heart failure, peripheral vascular disease, coagulopathy, actively smoking within last two years, in treatment for any form of cancer, positive tests for HIV, hepatitis B or C, or take systemic corticosteroids.
Subjects will also be excluded if they have an allergy to shellfish since glucosamine is derived from shellfish. Subjects will be excluded if they have taken glucosamine within the last three months. Subjects with allergies to blood products or eggs or known hypersensitivity to albumin will also be excluded from participating because of potential adverse effects from microbubble contrast agent. Subjects will be excluded from this study because children do not typically take glucosamine or have osteoarthritis.
|Ages ICMJE||21 Years to 65 Years (Adult, Older Adult)|
|Accepts Healthy Volunteers ICMJE||Yes|
|Contacts ICMJE||Contact information is only displayed when the study is recruiting subjects|
|Listed Location Countries ICMJE||United States|
|Removed Location Countries|
|NCT Number ICMJE||NCT00065377|
|Other Study ID Numbers ICMJE||030251
|Has Data Monitoring Committee||Not Provided|
|U.S. FDA-regulated Product||Not Provided|
|IPD Sharing Statement ICMJE||Not Provided|
|Responsible Party||Not Provided|
|Study Sponsor ICMJE||National Center for Complementary and Integrative Health (NCCIH)|
|Collaborators ICMJE||Not Provided|
|Investigators ICMJE||Not Provided|
|PRS Account||National Institutes of Health Clinical Center (CC)|
|Verification Date||June 2006|
ICMJE Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP