Arginase Inhibition in Humans With Obesity

Study Overview
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Brief Summary
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To evaluate the efficacy of arginase inhibition on endothelial function in humans with obesity.

Detailed Description
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The study is performed on one group of subjects with body mass index >35 and the absence of type 2 diabetes. Inclusion criteria: Body mass index >35 kg/m2. Exclusion criteria: Age >80 years. Type 2 diabetes defined as >7 mmol/L in fasting plasma glucose or >11 mmol/L following 2h of oral glycemic load. Myocardial infarction/unstable angina within 6 weeks prior to the study. Treatment with oral anticoagulants (Warfarin or New oral anticoagulants), Raynaud's phenomenon, peripheral vasculopathies, arterial shunting or other vascular surgery of the study arm. Any concomitant disease or condition that may interfere with the possibility for the patient to comply with or complete the study protocol. Participant in an ongoing study. Unwillingness to participate following oral and written information. Forearm blood flow is determined by venous occlusion plethysmography. Endothelium-dependent vasodilatation is determined during intra-brachial artery infusion of serotonin (21, 70 and 210 ng/min). Endothelium-independent vasodilatation is determined by infusion of sodium nitroprusside (SNP; 1, 3 and 10 µg/min). Each dose is given for 2 min at a rate of 2.5 ml/min. Data are expressed as percentage change in forearm blood from baseline flow. Fifteen subjects are included. On the day of the study the subject arrives to the laboratory after having a light breakfast. Forearm vessels of the non-dominant arm are cannulated and forearm blood flow is determined as described above. Baseline endothelium-dependent and endothelium-independent vasodilatation is determined by intra-arterial infusions of serotonin and SNP, respectively. Thereafter an intra-arterial infusion of the arginase inhibitor N-omega-hydroxy-nor-l-arginine (nor-NOHA) is administered as an intra-arterial infusion at a rate of 0.1 mg/min and is maintained for 120 min. The dose is based on a previous study by our group demonstrating improved endothelial function. Endothelium-dependent and -independent vasodilatation is reassessed at 120 min of infusion.

Official Title
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Arginase Inhibition and Endothelial Function in Humans With Obesity

Conditions
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Obese, Endothelial Function

Intervention / Treatment
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* Drug: Nω-hydroxy-nor-arginine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI >35kg/m2 Exclusion Criteria: Age >80 years. Type 2 diabetes defined as >7 mmol/L in fasting plasma glucose or >11 mmol/L following 2h of oral glycemic load. Myocardial infarction/unstable angina within 6 weeks prior to the study. Treatment with oral anticoagulants (Warfarin or New oral anticoagulants), Raynaud's phenomenon, peripheral vasculopathies, arterial shunting or other vascular surgery of the study arm. Any concomitant disease or condition that may interfere with the possibility for the patient to comply with or complete the study protocol. Participant in an ongoing study. Unwillingness to participate following oral and written information.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Arginase inhibition<br>Endothelium dependent and -independent vasodilatation before and after 120min intra-arterial administration of arginase the inhibitor N-omega-hydroxy-nor-l-arginine (nor-NOHA) is started and is maintained for 120 min at a rate of 0.1 mg/min | Drug: Nω-hydroxy-nor-arginine<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Endothelium-dependent change in forearm blood flow | Percentage change in forearm blood flow from baseline induced by the endothelium-dependent vasodilator serotonin during arginase blockade vs. saline. | 120 min intraarterial infusion of the arginase inhibitor nor-NOHA | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Endothelium-independent change in forearm blood flow | Percentage change in forearm blood flow from baseline induced by the endothelium-independent vasodilator nitroprusside during arginase blockade vs. saline. | 120 min intraarterial infusion of the arginase inhibitor nor-NOHA |