Contraction (Exercise) Mediated Glucose Uptake as a Therapeutic Target in Type 2 Diabetes
|First Received Date ICMJE||September 14, 2005|
|Last Updated Date||December 14, 2009|
|Start Date ICMJE||October 2002|
|Primary Completion Date||Not Provided|
|Current Primary Outcome Measures ICMJE
||glucose metabolism [ Time Frame: 3 hours ] [ Designated as safety issue: No ]|
|Original Primary Outcome Measures ICMJE||Not Provided|
|Change History||Complete list of historical versions of study NCT00168519 on ClinicalTrials.gov Archive Site|
|Current Secondary Outcome Measures ICMJE||Not Provided|
|Original Secondary Outcome Measures ICMJE||Not Provided|
|Current Other Outcome Measures ICMJE||Not Provided|
|Original Other Outcome Measures ICMJE||Not Provided|
|Brief Title ICMJE||Contraction (Exercise) Mediated Glucose Uptake as a Therapeutic Target in Type 2 Diabetes|
|Official Title ICMJE||Contraction Mediated Glucose Uptake as a Therapeutic Target in Type 2 Diabetes|
The purpose of this project is to determine whether glucose metabolism can be improved by administering a substance (nitric oxide donor) normally released by muscles during exercise.
Aim 1: To determine whether acute infusion of sodium nitroprusside, an NO donor, increases leg glucose uptake at rest in patients with type 2 diabetes.
Twenty male type 2 diabetic patients aged between 30 and 60 years will be recruited from our clinic and through advertisement. The inclusion criteria:
The leg blood flow (thermodilution) and glucose uptake responses (arterial-venous differences) to three cumulative doses of sodium nitroprusside (0.1, 0.3 and 0.6 ug.kg-1.min-1, 10 mins per dose) infused into the femoral artery using techniques established in our laboratory will be assessed. Doses are based on our extensive unpublished observations and have been calculated to lie on the linear part of the dose-response curve and to induce local and not systemic hemodynamic effects. As a control we will also assess responses to the nitrate independent vasodilator, Verapamil (Isoptin) (1, 3 and 6 ug.kg-1.min-1 Doses). Verapamil is a calcium channel antagonist which causes vasodilatation by direct actions on the smooth muscle. Doses will be titrated to give similar blood flow responses and the two drugs will be administered in randomized order with a 60 min wash-out period. Verapamil doses will be determined in pilot experiments. Vastus lateralis biopsies will be performed at baseline and after the highest dose of each drug and cGMP and GLUT-4 translocation measured.
A single Vastus lateralis biopsy will be performed as a comparison against type 2 diabetics.
Significance: This study will determine whether acute NO supplementation stimulates muscle GLUT-4 translocation and glucose uptake in patients with type 2 diabetes.
Pilot Study: To determine whether oral nitrates increase exhaled NO levels in healthy volunteers & to compare isosorbide mononitrate (ISMN) with pentaerythritol tetranitrate (PETN) to determine which drug is more effective in increasing exhaled NO.
Fifteen healthy male volunteers (as determined via a medical screening) aged between 18 and 65 years will be recruited through advertisement. The inclusion criteria for healthy controls will be:
Blood samples will be obtained and an oral glucose tolerance test (OGTT) performed. Baseline exhaled nitric oxide (NO) and pulmonary blood flow will be measured in collaboration with Dr Bruce Thompson from the Alfred Respiratory Department. Sodium nitroprusside (SNP) is a known NO donor and will be used as a positive control. Following baseline measurements participants will receive an intravenous (forearm vein) infusion of SNP (titrated from 0.3ug/kg/min to a maximum of 3 ug/kg/min over 30 minutes). Blood pressure will be monitored throughout using an automated sphygmomanometer. Post infusion exhaled NO and pulmonary blood flow will be measured.
Participants will then commence the second phase of the study to determine whether ISMN and PETN increase exhaled NO levels and to determine which drug is more potent in this regard.
Visit 2, 3 & 4: Participants will receive each of the following study medications in a randomised Latin square design:
There will be a 7-day wash-out period between each treatment/visit. Participants will undergo repeated measures of exhaled NO, pulmonary blood flow and OGTT three hours after each study drug has been administered. Blood will be taken prior to and every hour after the participant has taken each drug for measurement of NO metabolites (e.g. nitrite/nitrate, nitrosothiols, nitrosohemoglobin). Nitrate drugs are occasionally associated with headache and dizziness. Headaches can be treated with paracetamol.
Endpoints at baseline and post treatments will be:
Significance: Once the most effective NO donor has been determined it will be utilized in the chronic nitrate study described in Aim 2.
Aim 2: To determine whether chronic nitrate therapy for 12 weeks improves glucose tolerance and HbA1c in patients with type 2 diabetes.
Twenty male type 2 diabetic subjects aged between 30 and 60 years and meeting the inclusion criteria specified in Aim 1 will be recruited from our clinics and through advertisement. Patients will be randomized to 12 weeks of treatment with both long-acting nitrate therapy (isosorbide mononitrate 60mg daily, Imdur) and placebo (cross-over design). Primary endpoints will be:
To determine whether acute infusion of AICAR, an AMP analogue, increases leg glucose uptake at rest in patients with type 2 diabetes.
Twenty healthy males and twenty male type 2 diabetics aged between 30 and 60 years will be recruited from our clinic and through advertisement. The inclusion criteria for the diabetics will be:
The leg blood flow (thermodilution) and glucose uptake (arterial-venous differences) response to a 60 minute intra-femoral infusion of AICAR (1 mg.kg-1.min-1, Clinalfa, Switzerland) using techniques established in our laboratory will be assessed. As a control we will also measure responses to vehicle (saline) infusion prior to commencing the dose response curve (60 min). Plasma free fatty acids, glycerol, triglycerides and lactate will be determined and blood gases will be measured to assess respiratory quotient. Vastus lateralis biopsies will be performed at baseline and after AICAR and the following parameters quantitated:
|Study Type ICMJE||Interventional|
|Study Phase||Not Provided|
|Study Design ICMJE||Allocation: Randomized
Endpoint Classification: Pharmacokinetics/Dynamics Study
Intervention Model: Crossover Assignment
Masking: Single Blind (Subject)
Primary Purpose: Treatment
|Condition ICMJE||Diabetes Mellitus, Type 2|
|Intervention ICMJE||Drug: nitroprusside, pentalong, imdur, AICAR, isoptin
Sodium Nitroprusside - one 30 minute intravenous infusion
Pentalong - two tablets orally (total 160mg)
Imdur - two tablets orally (total 120mg)
|Study Arm (s)||Active Comparator: 1
Intervention: Drug: nitroprusside, pentalong, imdur, AICAR, isoptin
|Publications *||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|
|Estimated Enrollment ICMJE||40|
|Completion Date||April 2009|
|Primary Completion Date||Not Provided|
|Eligibility Criteria ICMJE||
Patients with type 2 diabetes
|Ages||18 Years to 65 Years|
|Accepts Healthy Volunteers||Yes|
|Contacts ICMJE||Contact information is only displayed when the study is recruiting subjects|
|Listed Location Countries ICMJE||Australia|
|Removed Location Countries|
|NCT Number ICMJE||NCT00168519|
|Other Study ID Numbers ICMJE||51/02|
|Has Data Monitoring Committee||Not Provided|
|Responsible Party||Not Provided|
|Study Sponsor ICMJE||Baker Heart Research Institute|
|Information Provided By||Baker Heart Research Institute|
|Verification Date||December 2009|
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