Anxiety-mediated Impairments in Large Elastic Artery Function and the Autonomic Nervous System
| Status: | Active, not recruiting |
|---|---|
| Conditions: | Anxiety, High Blood Pressure (Hypertension) |
| Therapuetic Areas: | Cardiology / Vascular Diseases, Psychiatry / Psychology |
| Healthy: | No |
| Age Range: | 18 - 79 |
| Updated: | 2/21/2019 |
| Start Date: | April 10, 2017 |
| End Date: | December 31, 2023 |
The goal of this study is to evaluate the effectiveness of a short-term (4 weeks)
pharmacological blockade of sympathetic nerve activity (clonidine) on anxiety symptoms,
vascular function, inflammation, muscle sympathetic nerve activity, and oxidant stress in
individuals with moderate-to-high anxiety. Individuals who are interested in the study will
be identified by an online screening survey and will be contacted by the research team;
advertisements, flyers and mass emails will direct individuals to the online screening
survey. Those deemed eligible to participate will be randomized to either the clonidine
intervention or hydrochlorothiazide as a blood-pressure lowering control condition. If
eligible participants are currently being treated with blood pressure-lowering medications,
they will be asked to go off these medications for 2 weeks prior to and during the course of
the study. During the 2 week washout of blood pressure-lowering medications, participants
will have safety visits (2 additional visits) that include measurements of blood pressure at
4 days and 7 days after the beginning of the washout period before the intervention.
Assessments of anxiety symptoms via various surveys, vascular function (via non-invasive,
well-established techniques), inflammation, muscle sympathetic nerve activity, and oxidant
stress will be performed at baseline and at the post intervention session. Similar baseline
measurements will be performed in control subjects with low or no anxiety for comparison, but
these individuals will not undergo the intervention.
Participants with moderate-to-high anxiety will have a total of 6 visits to the laboratory,
which includes the screening and consent (visit 1). Visit 2 (baseline measurements) and visit
6 (post-intervention measurements) will be more extensive (~4.5 hours) compared to the other
visits (~30 min). Participants completing the washout will have an additional 2 visits (~30
min each) before "visit 2." Control subjects with low or no anxiety will only participate in
visit 1 (screening and consent ) and visit 2 (baseline measurements).
pharmacological blockade of sympathetic nerve activity (clonidine) on anxiety symptoms,
vascular function, inflammation, muscle sympathetic nerve activity, and oxidant stress in
individuals with moderate-to-high anxiety. Individuals who are interested in the study will
be identified by an online screening survey and will be contacted by the research team;
advertisements, flyers and mass emails will direct individuals to the online screening
survey. Those deemed eligible to participate will be randomized to either the clonidine
intervention or hydrochlorothiazide as a blood-pressure lowering control condition. If
eligible participants are currently being treated with blood pressure-lowering medications,
they will be asked to go off these medications for 2 weeks prior to and during the course of
the study. During the 2 week washout of blood pressure-lowering medications, participants
will have safety visits (2 additional visits) that include measurements of blood pressure at
4 days and 7 days after the beginning of the washout period before the intervention.
Assessments of anxiety symptoms via various surveys, vascular function (via non-invasive,
well-established techniques), inflammation, muscle sympathetic nerve activity, and oxidant
stress will be performed at baseline and at the post intervention session. Similar baseline
measurements will be performed in control subjects with low or no anxiety for comparison, but
these individuals will not undergo the intervention.
Participants with moderate-to-high anxiety will have a total of 6 visits to the laboratory,
which includes the screening and consent (visit 1). Visit 2 (baseline measurements) and visit
6 (post-intervention measurements) will be more extensive (~4.5 hours) compared to the other
visits (~30 min). Participants completing the washout will have an additional 2 visits (~30
min each) before "visit 2." Control subjects with low or no anxiety will only participate in
visit 1 (screening and consent ) and visit 2 (baseline measurements).
Anxiety disorders are the most common mental health problems in the United States, occurring
in about 18% of adults per year, and a lifetime prevalence of approximately 28% (25).
Importantly, anxiety disorders are associated with increased risk for sudden cardiac death
and non-fatal myocardial infarction (27, 46) independent of other mood disorders (13, 15).
However, establishing a clear consensus on the mechanism(s) by which chronic anxiety confers
cardiovascular disease (CVD) risk has proven difficult. Previous studies examining the
potential role of vascular dysfunction in subjects with anxiety have been confounded by
co-morbidities (e.g., hypertension, smoking, obesity) (31, 38) and added psychiatric
disorders (63). Additionally, studies focusing on the relation between anxiety and robust
predictors of CVD mortality, such as large elastic artery (e.g., aortic, carotid) stiffness,
have been lacking.
Anxiety is experienced as negative feelings of threat, restlessness, tension and
irritability, and somatic symptoms, such as palpitations, sweating, trembling, and dry mouth
(57). Patients with clinically diagnosed anxiety disorder demonstrate more than 2-fold
increase in future CVD events (23). Despite the strong association between anxiety and CVD
risk, there is currently a gap in knowledge describing potential mechanisms by which anxiety
leads to CVD. Evidence suggests that chronically high levels of anxiety may be associated
with the progression of subclinical atherosclerosis such as carotid artery intima-media
thickness (38) and elevated inflammation (5, 44). Symptoms of anxiety may also lead to
impairment in resistance vessel dilator function (53). However, few studies have examined
large elastic artery stiffness in subjects with high levels of anxiety. This is clinically
important because large elastic artery stiffness (i.e., carotid and aortic) is a robust
independent risk factor for CVD events such as stroke and myocardial infarction (6, 19, 59,
61). Interestingly, greater large elastic artery stiffness (aortic) is observed with higher
resting muscle sympathetic nerve activity (MSNA) in healthy individuals even after adjusting
for BP (9, 55). In this regard, numerous studies have shown that high MSNA independent of any
increase in blood pressure can have deleterious vascular (7, 17, 32), metabolic (2, 20),
cardiac (50, 52), and renal effects (1, 14, 54). Higher tonic MSNA is an independent
determinant of aortic artery stiffness as assessed by the gold standard carotid-femoral pulse
wave velocity (PWV) in healthy humans (55). Even acute increases in MSNA, such as during
mental stress which is a potent stimulus for increases in MSNA (3), can lead to transiently
greater large elastic artery stiffness (40). Furthermore, in healthy humans, acute mental
stress induces transient endothelial dysfunction (16), an important modulator of arterial
stiffness. Given findings from previous studies (22) showing that anxiety symptoms are
associated with indices of elevated sympathetic nerve activity (e.g., elevated circulating
norepinephrine), lead us to our overall hypothesis that anxiety-induced sympathetic
overactivity leads to increased large elastic artery (carotid and aortic) stiffness in
subjects with chronic anxiety.
The purpose of this study is to 1) determine the extent to which measures of vascular and
autonomic function (large elastic artery stiffness, vascular inflammation and baroreflex
function) is impaired in subjects with moderate-to-high anxiety, and 2) test the magnitude by
which short-term (4 weeks) sympathetic nerve activity blockade (clonidine) improves large
elastic artery stiffness, vascular inflammation and baroreflex function in subjects with
moderate-to-high levels of anxiety.
In healthy subjects, chronic anxiety has been associated with increased risk of cardiac
events (13, 15, 23). Interestingly, evidence suggests baroreflex function is reduced in
subjects with anxiety (48, 60), thus adding additional cardiac risk burden to this
population. Consistent with this, impairment in cardiac baroreflex sensivity (BRS) is a
significant predictor of cardiac arrhythmias and myocardial infarction mortality (29, 56).
Moreover, reduced cardiac BRS is a sensitive predictor of mortality after myocardial
infarction (28, 30), particularly in subjects with anxiety (47). Reduced baroreflex
activation can be attributed, in part, to reduced distensibility of baroreceptor regions
within the elastic carotid and aortic arteries as a result of increased arterial stiffness
(8). Given the associated risk of cardiac BRS impairment with anxiety, and the increase in
large elastic artery stiffness in this population, there is a critical need to examine
whether reductions in SNA and large elastic artery stiffness ameliorates cardiac BRS
impairment in subjects with anxiety, thus providing experimental support for the novel idea
that anxiety leads to increased CVD risk at least in part through elevated large artery
stiffness.
in about 18% of adults per year, and a lifetime prevalence of approximately 28% (25).
Importantly, anxiety disorders are associated with increased risk for sudden cardiac death
and non-fatal myocardial infarction (27, 46) independent of other mood disorders (13, 15).
However, establishing a clear consensus on the mechanism(s) by which chronic anxiety confers
cardiovascular disease (CVD) risk has proven difficult. Previous studies examining the
potential role of vascular dysfunction in subjects with anxiety have been confounded by
co-morbidities (e.g., hypertension, smoking, obesity) (31, 38) and added psychiatric
disorders (63). Additionally, studies focusing on the relation between anxiety and robust
predictors of CVD mortality, such as large elastic artery (e.g., aortic, carotid) stiffness,
have been lacking.
Anxiety is experienced as negative feelings of threat, restlessness, tension and
irritability, and somatic symptoms, such as palpitations, sweating, trembling, and dry mouth
(57). Patients with clinically diagnosed anxiety disorder demonstrate more than 2-fold
increase in future CVD events (23). Despite the strong association between anxiety and CVD
risk, there is currently a gap in knowledge describing potential mechanisms by which anxiety
leads to CVD. Evidence suggests that chronically high levels of anxiety may be associated
with the progression of subclinical atherosclerosis such as carotid artery intima-media
thickness (38) and elevated inflammation (5, 44). Symptoms of anxiety may also lead to
impairment in resistance vessel dilator function (53). However, few studies have examined
large elastic artery stiffness in subjects with high levels of anxiety. This is clinically
important because large elastic artery stiffness (i.e., carotid and aortic) is a robust
independent risk factor for CVD events such as stroke and myocardial infarction (6, 19, 59,
61). Interestingly, greater large elastic artery stiffness (aortic) is observed with higher
resting muscle sympathetic nerve activity (MSNA) in healthy individuals even after adjusting
for BP (9, 55). In this regard, numerous studies have shown that high MSNA independent of any
increase in blood pressure can have deleterious vascular (7, 17, 32), metabolic (2, 20),
cardiac (50, 52), and renal effects (1, 14, 54). Higher tonic MSNA is an independent
determinant of aortic artery stiffness as assessed by the gold standard carotid-femoral pulse
wave velocity (PWV) in healthy humans (55). Even acute increases in MSNA, such as during
mental stress which is a potent stimulus for increases in MSNA (3), can lead to transiently
greater large elastic artery stiffness (40). Furthermore, in healthy humans, acute mental
stress induces transient endothelial dysfunction (16), an important modulator of arterial
stiffness. Given findings from previous studies (22) showing that anxiety symptoms are
associated with indices of elevated sympathetic nerve activity (e.g., elevated circulating
norepinephrine), lead us to our overall hypothesis that anxiety-induced sympathetic
overactivity leads to increased large elastic artery (carotid and aortic) stiffness in
subjects with chronic anxiety.
The purpose of this study is to 1) determine the extent to which measures of vascular and
autonomic function (large elastic artery stiffness, vascular inflammation and baroreflex
function) is impaired in subjects with moderate-to-high anxiety, and 2) test the magnitude by
which short-term (4 weeks) sympathetic nerve activity blockade (clonidine) improves large
elastic artery stiffness, vascular inflammation and baroreflex function in subjects with
moderate-to-high levels of anxiety.
In healthy subjects, chronic anxiety has been associated with increased risk of cardiac
events (13, 15, 23). Interestingly, evidence suggests baroreflex function is reduced in
subjects with anxiety (48, 60), thus adding additional cardiac risk burden to this
population. Consistent with this, impairment in cardiac baroreflex sensivity (BRS) is a
significant predictor of cardiac arrhythmias and myocardial infarction mortality (29, 56).
Moreover, reduced cardiac BRS is a sensitive predictor of mortality after myocardial
infarction (28, 30), particularly in subjects with anxiety (47). Reduced baroreflex
activation can be attributed, in part, to reduced distensibility of baroreceptor regions
within the elastic carotid and aortic arteries as a result of increased arterial stiffness
(8). Given the associated risk of cardiac BRS impairment with anxiety, and the increase in
large elastic artery stiffness in this population, there is a critical need to examine
whether reductions in SNA and large elastic artery stiffness ameliorates cardiac BRS
impairment in subjects with anxiety, thus providing experimental support for the novel idea
that anxiety leads to increased CVD risk at least in part through elevated large artery
stiffness.
Inclusion Criteria for participants with moderate-to-high anxiety to undergo drug
intervention:
- Willing and able to provide written, signed consent after the nature of the study has
been explained, and prior to any research-related procedures.
Age is > or = 18 and < or = 79 years
No history of cardiovascular disease (e.g., heart attack, stroke, heart failure, valvular
heart disease, cardiomyopathy), or peripheral arterial disease.
Non-smokers, defined as no history of smoking or no smoking for at least the past 3 months.
Normal resting 12-lead ECG (no evidence of myocardial infarction, left ventricular
hypertrophy, left-bundle branch block, 2nd or 3rd degree AV block, atrial
fibrillation/flutter, atherosclerosis).
Blood chemistries indicative of normal renal (creatinine <2.0mg/dl), liver (<3 times upper
limit for ALT, AST), and thyroid function (TSH between 0.4 - 5.0 mU/L) or on stable thyroid
medication with no dose change for 3 months.
Exclusion Criteria:
- Current use of clonidine or beta-blockers
Current use of antihypertensive medications for reasons other than hypertension (e.g.,
hydrochlorothiazide for leg edema or kidney stone prevention, beta-blockers for tremor)
Difficult to control hypertension (e.g., on 2 or 3 antihypertensive medications)
Low blood pressure (e.g., systolic BP < 110 mmHg)
Hypertensive and have not been stable on their current antihypertensive medication regimen
for at least 6 months
Blood pressure not controlled either on or off antihypertensive medications (e.g., BP >
150/100)
Current diagnosis or history of cancer, liver disease, HIV/AIDS
History of brain tumor, aneurysm or injury
Clinical diagnosis of mental health disorders such as bipolar disorder or schizophrenia
History of cardiovascular disease such as heart angioplasty/stent or bypass surgery,
myocardial infarction, stroke, heart failure with or without LV ejection fraction <40%,
cardiomyopathy, valvular heart disease, cardiomyopathy, heart transplantation,
atherosclerosis.
Current tobacco user or history of tobacco use within the past 3 months (cigarettes,
cigars, chewing tobacco, Hookah).
History of lung emphysema, chronic bronchitis or chronic obstructive pulmonary disease
(COPD).
Abnormal resting 12-lead ECG (e.g., evidence of myocardial infarction, left ventricular
hypertrophy, left-bundle branch block, 2nd or 3rd degree AV block, atrial
fibrillation/flutter, atherosclerosis).
Serious neurologic disorders including seizures.
History of renal failure, dialysis or kidney transplant.
Use of any investigational products or investigational medical devices within 30 days prior
to screening, or requirement for any investigational agent prior to completion of all
scheduled study assessments.
Recent flu-like symptoms within the past 2 weeks.
Pregnant or breastfeeding at screening, or planning to become pregnant (self or partner) at
any time during the study. A urinary pregnancy test will be done on all females. If test is
positive, the subject will be excluded.
History of rheumatoid arthritis, Grave's disease, systemic lupus erythamatosis, and
Wegener's granulomatosis.
Taking anticoagulation, anti-seizure, or antipsychotic agents.
Start of or dose change to an antidepressant or anti-anxiety medication within the past 3
months (if no change in medication or dose in past 3 month, then subject will be eligible).
Immunodeficiency or systemic autoimmune disease.
History of bleeding disorders or conditions of the microcirculation (i.e. von Willebrand
disease, Raynaud's disease).
History of co-morbid condition that would limit life expectancy to <1 year.
Taking chronic non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin,
indomethacin, naproxen, acetaminophen (Tylenol®), ibuprofen (Advil®, Motrin®) and not able
or willing to go off of for 2 weeks prior to each study visit.
Taking cox-2 inhibitors (Celebrex®, Vioxx®, etc) or allopurinol (Zyloprim®, Lopurin®,
Aloprim®).
Taking steroids or biologics: corticosteroids (prednisone); methotrexate, infliximib
(Remicade®), etaneracept (Enbrel®); anakinra (Kineret®).
Those who are currently donating blood, platelets, or plasma at the time of screening.
Vulnerable populations (prisoners, etc.) will not be eligible to participate in this study.
On weight loss drugs (i.e. orilistat (Xenical®), sibutramine (Meridia®),
phenylpropanol-amine (Acutrim®)), or similar over-the-counter medications within 3 months
of screening.
Any surgery within 30 days of screening
Those who currently donate blood, platelets, or plasma
Any condition that, in the view of the PI or Co-I, places the subject at high risk or poor
treatment and study compliance.
We will also enroll 36 participants ages 18-79 years (50% men, 50% women) with low or no
anxiety as control subjects to participate in only baseline testing (not participate in the
drug intervention).
Inclusion criteria:
Willing and able to provide written, signed consent after the nature of the study has been
explained, and prior to any research-related procedures.
Age is > or = 18 and < or = 79 years
No history of cardiovascular disease (e.g., heart attack, stroke, heart failure, valvular
heart disease, cardiomyopathy), or peripheral arterial disease.
Non-smokers, defined as no history of smoking or no smoking for at least the past 3 months.
Normal resting 12-lead ECG (no evidence of myocardial infarction, left ventricular
hypertrophy, left-bundle branch block, 2nd or 3rd degree AV block, atrial
fibrillation/flutter, atherosclerosis).
Blood chemistries indicative of normal renal (creatinine <2.0mg/dl), liver (<3 times upper
limit for ALT, AST), and thyroid function (TSH between 0.4 - 5.0 mU/L) or on stable thyroid
medication with no dose change for 3 months.
Exclusion Criteria:
Current use of clonidine or beta-blockers
Current use of antihypertensive medications for reasons other than hypertension (e.g.,
hydrochlorothiazide for leg edema or kidney stone prevention, beta-blockers for tremor)
Difficult to control hypertension (e.g., on 2 or 3 antihypertensive medications)
Low blood pressure (e.g., systolic BP < 110 mmHg)
Hypertensive and have not been stable on their current antihypertensive medication regimen
for at least 6 months
Blood pressure not controlled either on or off antihypertensive medications (e.g., BP >
150/100)
Current diagnosis or history of cancer, liver disease, HIV/AIDS
History of brain tumor, aneurysm or injury
Clinical diagnosis of mental health disorders such as bipolar disorder or schizophrenia
History of cardiovascular disease such as heart angioplasty/stent or bypass surgery,
myocardial infarction, stroke, heart failure with or without LV ejection fraction <40%,
cardiomyopathy, valvular heart disease, cardiomyopathy, heart transplantation,
atherosclerosis.
Current tobacco user or history of tobacco use within the past 3 months (cigarettes,
cigars, chewing tobacco, Hookah).
History of lung emphysema, chronic bronchitis or chronic obstructive pulmonary disease
(COPD).
Abnormal resting 12-lead ECG (e.g., evidence of myocardial infarction, left ventricular
hypertrophy, left-bundle branch block, 2nd or 3rd degree AV block, atrial
fibrillation/flutter, atherosclerosis).
Serious neurologic disorders including seizures.
History of renal failure, dialysis or kidney transplant.
Use of any investigational products or investigational medical devices within 30 days prior
to screening, or requirement for any investigational agent prior to completion of all
scheduled study assessments.
Recent flu-like symptoms within the past 2 weeks.
Pregnant or breastfeeding at screening, or planning to become pregnant (self or partner) at
any time during the study. A urinary pregnancy test will be done on all females. If test is
positive, the subject will be excluded.
History of rheumatoid arthritis, Grave's disease, systemic lupus erythamatosis, and
Wegener's granulomatosis.
Taking anticoagulation, anti-seizure, or antipsychotic agents.
Start of or dose change to an antidepressant or anti-anxiety medication within the past 3
months (if no change in medication or dose in past 3 month, then subject will be eligible).
Immunodeficiency or systemic autoimmune disease.
History of bleeding disorders or conditions of the microcirculation (i.e. von Willebrand
disease, Raynaud's disease).
History of co-morbid condition that would limit life expectancy to <1 year.
Taking chronic non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin,
indomethacin, naproxen, acetaminophen (Tylenol®), ibuprofen (Advil®, Motrin®) and not able
or willing to go off of for 2 weeks prior to each study visit.
Taking cox-2 inhibitors (Celebrex®, Vioxx®, etc) or allopurinol (Zyloprim®, Lopurin®,
Aloprim®).
Taking steroids or biologics: corticosteroids (prednisone); methotrexate, infliximib
(Remicade®), etaneracept (Enbrel®); anakinra (Kineret®).
Those who are currently donating blood, platelets, or plasma at the time of screening.
Vulnerable populations (prisoners, etc.) will not be eligible to participate in this study.
On weight loss drugs (i.e. orilistat (Xenical®), sibutramine (Meridia®),
phenylpropanol-amine (Acutrim®)), or similar over-the-counter medications within 3 months
of screening.
Any surgery within 30 days of screening
Those who currently donate blood, platelets, or plasma
Any condition that, in the view of the PI or Co-I, places the subject at high risk or poor
treatment and study compliance.
We will also enroll 36 participants ages 18-79 years (50% men, 50% women) with low or no
anxiety as control subjects to participate in only baseline testing (not participate in the
drug intervention). These subjects will be either lean (body mass index < 25) or on the
obesity spectrum (body mass index > 30).
Because obesity is linked with hypertension and type 2 diabetes, enrollment of subjects may
include those with pre-hypertension or hypertension (systolic blood pressure >/= 120 - <180
mmHg- average of at least 3 measurements 2 min apart after 10 min seated resting position),
and/or pre-diabetes (defined as fasting blood glucose between 100-126 mg/dl, fasting blood
glucose of 140-199 mg/dl at 120 min of an oral glucose tolerance test, or HbA1C of 6-6.5%)
or type 2 diabetes (defined as fasting blood glucose between >126 mg/dl, fasting blood
glucose of >199 mg/dl at 120 min of an oral glucose tolerance test, or HbA1C > 6.5%). These
subjects may be taking anti-hypertensive and/or diabetes (anti-hyperglycemic) medications.
Subjects will be asked to refrain from medications the morning of the study visit, and to
bring their medications with them to take immediately following their study visit.
Inclusion criteria:
Willing and able to provide written, signed consent after the nature of the study has been
explained, and prior to any research-related procedures.
Age is > or = 18 and < or = 79 years
No history of cardiovascular disease (e.g., heart attack, stroke, heart failure, valvular
heart disease, cardiomyopathy), or peripheral arterial disease.
Non-smokers, defined as no history of smoking or no smoking for at least the past 3 months.
Normal resting 12-lead ECG (no evidence of myocardial infarction, left ventricular
hypertrophy, left-bundle branch block, 2nd or 3rd degree AV block, atrial
fibrillation/flutter, atherosclerosis).
Blood chemistries indicative of normal renal (creatinine <2.0mg/dl), liver (<3 times upper
limit for ALT, AST), and thyroid function (TSH between 0.4 - 5.0 mU/L) or on stable thyroid
medication with no dose change for 3 months.
Exclusion Criteria:
Current diagnosis or history of cancer, liver disease, HIV/AIDS
History of brain tumor, aneurysm or injury
Clinical diagnosis of mental health disorders such as bipolar disorder or schizophrenia
History of cardiovascular disease such as heart angioplasty/stent or bypass surgery,
myocardial infarction, stroke, heart failure with or without LV ejection fraction <40%,
cardiomyopathy, valvular heart disease, cardiomyopathy, heart transplantation,
atherosclerosis.
Current tobacco user or history of tobacco use within the past 3 months (cigarettes,
cigars, chewing tobacco, Hookah).
History of lung emphysema, chronic bronchitis or chronic obstructive pulmonary disease
(COPD).
Abnormal resting 12-lead ECG (e.g., evidence of myocardial infarction, left ventricular
hypertrophy, left-bundle branch block, 2nd or 3rd degree AV block, atrial
fibrillation/flutter, atherosclerosis).
Serious neurologic disorders including seizures.
History of renal failure, dialysis or kidney transplant.
Use of any investigational products or investigational medical devices within 30 days prior
to screening, or requirement for any investigational agent prior to completion of all
scheduled study assessments.
Recent flu-like symptoms within the past 2 weeks.
Pregnant or breastfeeding at screening, or planning to become pregnant (self or partner) at
any time during the study. A urinary pregnancy test will be done on all females. If test is
positive, the subject will be excluded.
History of rheumatoid arthritis, Grave's disease, systemic lupus erythamatosis, and
Wegener's granulomatosis.
Taking anticoagulation, anti-seizure, or antipsychotic agents.
Start of or dose change to an antidepressant or anti-anxiety medication within the past 3
months (if no change in medication or dose in past 3 month, then subject will be eligible).
Immunodeficiency or systemic autoimmune disease.
History of bleeding disorders or conditions of the microcirculation (i.e. von Willebrand
disease, Raynaud's disease).
History of co-morbid condition that would limit life expectancy to <1 year.
Taking chronic non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin,
indomethacin, naproxen, acetaminophen (Tylenol®), ibuprofen (Advil®, Motrin®) and not able
or willing to go off of for 2 weeks prior to each study visit.
Taking cox-2 inhibitors (Celebrex®, Vioxx®, etc) or allopurinol (Zyloprim®, Lopurin®,
Aloprim®).
Taking steroids or biologics: corticosteroids (prednisone); methotrexate, infliximib
(Remicade®), etaneracept (Enbrel®); anakinra (Kineret®).
Those who are currently donating blood, platelets, or plasma at the time of screening.
Vulnerable populations (prisoners, etc.) will not be eligible to participate in this study.
On weight loss drugs (i.e. orilistat (Xenical®), sibutramine (Meridia®),
phenylpropanol-amine (Acutrim®)), or similar over-the-counter medications within 3 months
of screening.
Any surgery within 30 days of screening
Those who currently donate blood, platelets, or plasma
Any condition that, in the view of the PI or Co-I, places the subject at high risk or poor
treatment and study compliance.
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