Obesity
Conditions
Keywords
Bradykinin, Obesity, Nitric Oxide Donor, tissue type plasminogen activator, isosorbide dinitrate, phosphodiesterase inhibitor, Renin-Angiotensin Aldosterone System, Fibrinolysis, Angiotensin converting enzyme
Brief summary
The purpose of the study is to determine if giving isosorbide,a drug that is used to treat chest pain, affects blood vessel release of an anti-clotting factor.
Detailed description
To test the hypothesis that the administration of the NO donor isosorbide dinitrate,but not the phosphodiesterase inhibitor sildenafil, will attenuate stimulated vascular t-PA release whereas both agents will improve glucose uptake.
Interventions
DRUGControl (bradykinin)
Graded doses of bradykinin (Clinalfa AG, Läufelfingen, Switzerland) will be infused at 50, 100, and 200ng/min. Each dose will be infused for 5 minutes and FBF will measured during the last 2 minutes of infusion. Arterial and venous blood samples will be obtained for measurement of net t-PA release after each dose.
DRUGL-NMMA + bradykinin
Thirty minutes after administration of bradykinin a continuous intra-arterial infusion of L-NMMA at 12 micromol/min will be started started. While continuing the infusion of L-NMMA, baseline measurements and infusion of bradykinin will be repeated.
DRUGIsosorbide + L-NMMA + bradykinin
Following the second bradykinin infusion, 12 subjects will receive 5mg isosorbide dinitrate (an exogenous NO donor; Major Pharmaceuticals Inc, Livonia MI). Sixty minutes after the administration of isosorbide the continuous intra-arterial infusion of L-NMMA at 12 micromol/min will be restarted and baseline measurements and bradykinin infusion will be repeated.
DRUGSildenafil + L-NMMA + bradykinin
Following the second bradykinin infusion, 12 subjects will receive 50mg sildenafil (phosphodiesterase type 5 (PDE5) inhibitor to increase cGMP without increasing NO; Pfizer, NY). Sixty minutes after the administration of sildenafil the continuous intra-arterial infusion of L-NMMA at 12 micromol/min will be restarted and baseline measurements and bradykinin infusion will be repeated.
Sponsors
National Institutes of Health (NIH)
National Center for Research Resources (NCRR)
National Heart, Lung, and Blood Institute (NHLBI)
Vanderbilt University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
HEALTH_SERVICES_RESEARCH
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
Yes
Inclusion criteria
* 18-70 years of age * Male and female subjects * Surgical sterilization * Childbearing potential: beta HCG on study day * Subjects with a body mass index of 25 or greater
Exclusion criteria
* Diabetes type 1 to type 2 as defined by a fasting glucose of 126 mg/dl or greater or the use of anti-diabetic medication * Use of hormone replacement therapy * Statin therapy * In hypertensive subjects, a seated systolic blood pressure greater than 179 mmHg or a seated diastolic blood pressure greater than 110 mmHg or taking hypertensives * Pregnancy/Breast Feeding * Cardiovascular disease such as myocardial infarction with 6 months prior to enrollment, presence of angina pectoris, significant arrhythmia, congestive heart failure (LV hypertrophy acceptable) deep vein thrombosis, pulmonary embolism, second or three degree heart block, mitral valve stenosis, aortic stenosis, or hypertrophic cardiomyopathy * Treatment with anticoagulants * History of serious neurologic disease such as cerebral hemorrhage, stroke or transient ischemic attack * Diagnosis of asthma * Clinically significant gastrointestinal impairment that could interfere with drug absorption * Hematocrit \<35% * Hyperlipidemic fasting Total Cholesterol \>220mg/dl * Impaired renal function (Serum creatinine \>1.5 mg/dl) * History or presence of immunological or hematological disorders * Any underlying or acute disease requiring regular medication which could possible pose a threat to the subject or make implementation of the protocol or interpretation of the study results difficult * Impaired hepatic function (Serum glutamic oxaloacetic transaminase, serum glutamate pyruvate transaminase \> 60) * Treatment with chronic systemic glucocorticoid therapy (more than 7 days in 1 month) * Treatment with lithium salts * History of Alcohol or drug abuse * Treatment with any investigational drug 1 month preceding study * Mental conditions rendering the subject unable to understand the nature, scope and possible consequences of the study * Inability to comply with the protocol
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Net Tissue-type Plasminogen Activator (t-PA) Release | During and after each study drug administration | Individual net t-PA release at each time point were calculated by the following formula: net release = (Cv-CA) x {FBF x \[101-hematocrit/100\]}, where Cv and CA represent the concentration of t-PA in the brachial vein and artery, respectively. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Forearm Blood Flow (FBF) | During and after each study drug administration | Forearm blood flow was measured by strain gauge plethysmography |
Other
| Measure | Time frame | Description |
|---|---|---|
| Net Glucose Uptake | At baseline and after maximum dose of bradykinin | Individual net reuptake rates at each time point were calculated by the following formula: net uptake = (Cv-CA) x {FBF x \[101-hematocrit/100\]}, where Cv and CA represent the concentration of glucose in the brachial vein and artery, respectively. |
Countries
United States
Participant flow
Recruitment details
Subjects were recruited from a volunteer registry at Vanderbilt University. Subjects who participated in prior studies and requested to be contacted for future studies were included in the recruitment process. Recruitment began on 12/07 and stopped on 1/09.
Pre-assignment details
Subjects with renal, endocrine, hematological or cardiovascular disease (including hypertension defined as an untreated systolic/diastolic blood pressure greater than 140/90 mmHg were excluded. Subjects with a fasting cholesterol greater than 5.7 mmol/L (220 mg/dl) and smokers were excluded. No washout period was required for the study.
Participants by arm
| Arm | Count |
|---|---|
| All Participants Subjects characteristics for all 24 participants | 24 |
| Total | 24 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| L-NMMA + Bradykinin | Physician Decision | 1 |
Baseline characteristics
| Characteristic | All Participants |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 24 Participants |
| Age Continuous | 31.71 years STANDARD_DEVIATION 6.51 |
| Region of Enrollment United States | 24 participants |
| Sex: Female, Male Female | 12 Participants |
| Sex: Female, Male Male | 12 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | — / — |
| other Total, other adverse events | 4 / 24 |
| serious Total, serious adverse events | 0 / 24 |
Outcome results
Primary
Net Tissue-type Plasminogen Activator (t-PA) Release
Individual net t-PA release at each time point were calculated by the following formula: net release = (Cv-CA) x {FBF x \[101-hematocrit/100\]}, where Cv and CA represent the concentration of t-PA in the brachial vein and artery, respectively.
Time frame: During and after each study drug administration
Population: Twenty four subjects were studied. One subject was excluded because of erroneous drug administration. Analysis was per protocol. Twenty-three subjects receive bradykinin then L-NMMA plus bradykinin infusions. Subjects were then randomized to either isosorbide or sildenafil. Twelve subjects received sildenafil and 11 subjects received isosorbide.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Control | Net Tissue-type Plasminogen Activator (t-PA) Release | Net t-PA release (bradykinin 100ng/min) | 11.81 ng/min/100ml | Standard Error 2.12 |
| Control | Net Tissue-type Plasminogen Activator (t-PA) Release | Net t-PA release (bradykinin 200ng/min) | 30.03 ng/min/100ml | Standard Error 4.24 |
| Control | Net Tissue-type Plasminogen Activator (t-PA) Release | Net t-PA release (bradykinin 50ng/min) | 1.02 ng/min/100ml | Standard Error 1.06 |
| Control | Net Tissue-type Plasminogen Activator (t-PA) Release | Net t-PA release (bradykinin 0ng/min) | 0.24 ng/min/100ml | Standard Error 0.39 |
| L-NMMA + Control | Net Tissue-type Plasminogen Activator (t-PA) Release | Net t-PA release (bradykinin 50ng/min) | 3.65 ng/min/100ml | Standard Error 0.79 |
| L-NMMA + Control | Net Tissue-type Plasminogen Activator (t-PA) Release | Net t-PA release (bradykinin 100ng/min) | 22.10 ng/min/100ml | Standard Error 5.51 |
| L-NMMA + Control | Net Tissue-type Plasminogen Activator (t-PA) Release | Net t-PA release (bradykinin 0ng/min) | 0.59 ng/min/100ml | Standard Error 0.23 |
| L-NMMA + Control | Net Tissue-type Plasminogen Activator (t-PA) Release | Net t-PA release (bradykinin 200ng/min) | 39.90 ng/min/100ml | Standard Error 6.98 |
| Isosorbide + L-NMMA + Control | Net Tissue-type Plasminogen Activator (t-PA) Release | Net t-PA release (bradykinin 100ng/min) | 15.90 ng/min/100ml | Standard Error 3.13 |
| Isosorbide + L-NMMA + Control | Net Tissue-type Plasminogen Activator (t-PA) Release | Net t-PA release (bradykinin 0ng/min) | -0.38 ng/min/100ml | Standard Error 0.51 |
| Isosorbide + L-NMMA + Control | Net Tissue-type Plasminogen Activator (t-PA) Release | Net t-PA release (bradykinin 50ng/min) | 3.14 ng/min/100ml | Standard Error 1.13 |
| Isosorbide + L-NMMA + Control | Net Tissue-type Plasminogen Activator (t-PA) Release | Net t-PA release (bradykinin 200ng/min) | 45.32 ng/min/100ml | Standard Error 9.45 |
| Sildenafil + L-NMMA + Control | Net Tissue-type Plasminogen Activator (t-PA) Release | Net t-PA release (bradykinin 0ng/min) | 0.29 ng/min/100ml | Standard Error 0.67 |
| Sildenafil + L-NMMA + Control | Net Tissue-type Plasminogen Activator (t-PA) Release | Net t-PA release (bradykinin 100ng/min) | 18.48 ng/min/100ml | Standard Error 9.11 |
| Sildenafil + L-NMMA + Control | Net Tissue-type Plasminogen Activator (t-PA) Release | Net t-PA release (bradykinin 200ng/min) | 37.39 ng/min/100ml | Standard Error 11.79 |
| Sildenafil + L-NMMA + Control | Net Tissue-type Plasminogen Activator (t-PA) Release | Net t-PA release (bradykinin 50ng/min) | 2.46 ng/min/100ml | Standard Error 2.07 |
Comparison: The effect of bradykinin on net t-PA release was determined using general linear model-repeated measures ANOVA in which the between-subject variable was gender, and the within-subjects variables were drug (control, +L-NMMA, +L-NMMA plus isosorbide, or +L-NMMA plus sildenafil) and dose of bradykinin.p-value: 0.04ANOVA
Secondary
Forearm Blood Flow (FBF)
Forearm blood flow was measured by strain gauge plethysmography
Time frame: During and after each study drug administration
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Control | Forearm Blood Flow (FBF) | FBF (bradykinin 0 ng/min) | 4.03 ml/min/100ml | Standard Error 0.25 |
| Control | Forearm Blood Flow (FBF) | FBF (bradykinin 50ng/min) | 7.02 ml/min/100ml | Standard Error 0.57 |
| Control | Forearm Blood Flow (FBF) | FBF (bradykinin 100ng/min) | 13.17 ml/min/100ml | Standard Error 1.04 |
| Control | Forearm Blood Flow (FBF) | FBF (bradykinin 200 ng/min) | 17.74 ml/min/100ml | Standard Error 1.43 |
| L-NMMA + Control | Forearm Blood Flow (FBF) | FBF (bradykinin 50ng/min) | 5.16 ml/min/100ml | Standard Error 0.37 |
| L-NMMA + Control | Forearm Blood Flow (FBF) | FBF (bradykinin 100ng/min) | 8.67 ml/min/100ml | Standard Error 0.81 |
| L-NMMA + Control | Forearm Blood Flow (FBF) | FBF (bradykinin 200 ng/min) | 11.21 ml/min/100ml | Standard Error 1.12 |
| L-NMMA + Control | Forearm Blood Flow (FBF) | FBF (bradykinin 0 ng/min) | 2.36 ml/min/100ml | Standard Error 0.18 |
| Isosorbide + L-NMMA + Control | Forearm Blood Flow (FBF) | FBF (bradykinin 100ng/min) | 6.83 ml/min/100ml | Standard Error 1.13 |
| Isosorbide + L-NMMA + Control | Forearm Blood Flow (FBF) | FBF (bradykinin 50ng/min) | 4.73 ml/min/100ml | Standard Error 0.7 |
| Isosorbide + L-NMMA + Control | Forearm Blood Flow (FBF) | FBF (bradykinin 200 ng/min) | 9.91 ml/min/100ml | Standard Error 1.72 |
| Isosorbide + L-NMMA + Control | Forearm Blood Flow (FBF) | FBF (bradykinin 0 ng/min) | 2.18 ml/min/100ml | Standard Error 0.33 |
| Sildenafil + L-NMMA + Control | Forearm Blood Flow (FBF) | FBF (bradykinin 200 ng/min) | 12.92 ml/min/100ml | Standard Error 1.3 |
| Sildenafil + L-NMMA + Control | Forearm Blood Flow (FBF) | FBF (bradykinin 50ng/min) | 5.87 ml/min/100ml | Standard Error 0.79 |
| Sildenafil + L-NMMA + Control | Forearm Blood Flow (FBF) | FBF (bradykinin 0 ng/min) | 2.80 ml/min/100ml | Standard Error 0.37 |
| Sildenafil + L-NMMA + Control | Forearm Blood Flow (FBF) | FBF (bradykinin 100ng/min) | 9.13 ml/min/100ml | Standard Error 0.76 |
p-value: <0.001ANOVA
Other Pre-specified
Net Glucose Uptake
Individual net reuptake rates at each time point were calculated by the following formula: net uptake = (Cv-CA) x {FBF x \[101-hematocrit/100\]}, where Cv and CA represent the concentration of glucose in the brachial vein and artery, respectively.
Time frame: At baseline and after maximum dose of bradykinin
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Control | Net Glucose Uptake | Net glucose uptake (bradykinin 0 ng/min) | -79.95 microgram/min/100ml | Standard Error 22.894 |
| Control | Net Glucose Uptake | Net glucose uptake (bradykinin 200 ng/min) | -319.85 microgram/min/100ml | Standard Error 97.109 |
| L-NMMA + Control | Net Glucose Uptake | Net glucose uptake (bradykinin 200 ng/min) | -142.86 microgram/min/100ml | Standard Error 49.935 |
| L-NMMA + Control | Net Glucose Uptake | Net glucose uptake (bradykinin 0 ng/min) | -74.36 microgram/min/100ml | Standard Error 7.125 |
| Isosorbide + L-NMMA + Control | Net Glucose Uptake | Net glucose uptake (bradykinin 0 ng/min) | -71.4 microgram/min/100ml | Standard Error 27.74 |
| Isosorbide + L-NMMA + Control | Net Glucose Uptake | Net glucose uptake (bradykinin 200 ng/min) | -163.233 microgram/min/100ml | Standard Error 36.504 |
| Sildenafil + L-NMMA + Control | Net Glucose Uptake | Net glucose uptake (bradykinin 0 ng/min) | -67.3 microgram/min/100ml | Standard Error 13.17 |
| Sildenafil + L-NMMA + Control | Net Glucose Uptake | Net glucose uptake (bradykinin 200 ng/min) | -125.32 microgram/min/100ml | Standard Error 45.705 |