Effect of Gamma Tocopherol Enriched Supplementation on Response to Inhaled LPS

BACKGROUND:

Allergic asthma (AA) is the most commonly encountered respiratory disease in children and
adults in the United States and is a leading cause of morbidity worldwide. Among the most
disruptive expressions of disease in AA is acute asthma exacerbation. The Center for Disease
Control lists ambient air pollutants and environmental tobacco smoke as among the most common
triggers for acute asthma exacerbation. Ozone (O3) is the most commonly encountered ambient
air pollutant in the US. Endotoxin (or lipopolysaccharide or LPS) is a component of
bioaerosols found in both the indoor and outdoor environment, is a component of tobacco
smoke, and is increased in indoor settings where smokers live. LPS is also a component of
coarse and fine mode particle matter air pollution.

OXIDATIVE STRESS AND ASTHMA:

Increased oxidative stress and decreased antioxidant capability have been observed in
asthmatics. These pollutants are pro-inflammatory and are associated with increased oxidative
stress, which would exacerbate reactive oxygen and reactive nitrogen species (ROS and
RNS)-induced injury in asthmatics. O3 injures epithelial cells, releasing secondary mediators
which activate inflammatory cells, in part by ligation of Toll-Like Receptor 4 (TLR4), the
primary receptor for LPS. TLR4 activation of inflammatory cells activates Nuclear Factor-kB
(NF-kB) and induces oxidative stress. O3 and LPS has been associated with exacerbation of
asthma, and we have reported that O3 and LPS augments allergic airway inflammation in
allergic asthmatics (AA). Development of interventions to mitigate these responses will
greatly decrease disease morbidity.

Given the role that oxidants play in the pathophysiology of asthma exacerbation, defects in
antioxidant levels would increase risk for acute asthma exacerbation. Nutritional
deficiencies in vitamin E, ascorbate and selenium have been linked to asthma severity, and
asthmatics have decreased antioxidant levels in airway fluid. We and others have shown that
vitamins C and E are decreased in airway fluids of asthmatics. Additionally, genetic factors
may increase risk for oxidant induced exacerbation of asthma. Many investigators have
reported that persons who are homozygous for the null polymorphism of the
Glutathione-S-Transferase Mu1 (GSTM1) gene and unable to produce GSTM1 protein (the GSTM1
null genotype) have increased risk of acute pollutant-induced exacerbation of asthma. We have
shown in healthy volunteers that the GSTM1 null genotype is associated with increased
inflammatory response to O3, with no impact on the nociceptive response to this pollutant. We
have also shown that GSTM1 null volunteers have enhanced airway and systemic inflammation
following LPS challenge.

Others have shown that the GSTM1 null genotype is associated with increased response to
secondhand tobacco smoke, diesel exhaust, and other particulate matter components. Romieu et
al demonstrated that children with asthma in Mexico City were had increases susceptibility to
O3-induced exacerbations if they had the GSTM1 null genotype. This group also found that
GSTM1 null AAs selectively benefited from antioxidant intervention. The GSTM1 null genotype
is found in 20-40% of the population, and may be overrepresented in allergic populations.
Taken together, these observations show that the sizable GSTM1 null population is at risk for
pollutant-induced airway disease, and that antioxidant intervention targeting the action of
ROS and RNS will benefit asthmatics and especially GSTM1 null asthmatics.

ANTIOXIDANTS AND ASTHMA:

A non-exclusive list of proposed antioxidants includes radical scavengers such as ascorbate,
a-tocopherol (aT), y-tocopherol (yT) or inducers of the antioxidant gene response element
transcription factor NRF2, which activate NRF2 with subsequent broad upregulation of acute
phase II and antioxidant proteins. These agents are available in naturally occurring foods
and as nutritional supplements. A number of animal, cell culture and epidemiological studies
support the idea that antioxidant supplementation is useful in allergic airway disease.
However, despite these studies and widespread public and scientific enthusiasm regarding use
of such agents in asthmatics, there are scant human data to support or refute the use of such
interventions for either acute or chronic allergic airways disease. It is crucial that
adequate, well-designed human studies assess the role of antioxidants for allergic asthma to
either confirm their efficacy, or refute claims that these are effective, safe and low cost
interventions for allergic disease.

GAMMA TOCOPHEROL AND ASTHMA:

Gamma tocopherol has both radical scavenging and anti-inflammatory actions which may play
important roles in decreasing pollutant-induced and allergic injury to the airway.

Like other isoforms of vitamin E, yT is a potent ROS scavenger and is also a powerful
nucleophile that traps electrophiles such as peroxynitrite in lipophilic compartments. One
mechanism by which y-T is cytoprotective is scavenging of RNS at the un-substituted C-5
position on the hydroxy-chroman ring of y-T to form 5-NO-y-tocopherol (5-NO-yT). Overall,
vitamin E provides general protection of DNA, lipids and proteins from radical stress. An
example of such protection is shown in rodent studies of prostate cancer in which intake of
yT is associated with decreased DNA methylation of CpG rich regions of the NRF2. NRF2 is a
master regulator of numerous cytoprotective antioxidant enzymes.

Supplementation with yT also prevents protein nitration and attenuates loss of plasma vitamin
C in plasma in a rodent peritonitis model of inflammation. Our group has also shown that yT
inhibits cyclo-oxygenase-2 (COX-2) and 5-lipoxygenase (5-LO) in LPS-stimulated macrophages
and interleukin (IL)-1b stimulated epithelial cells. These actions are mediated primarily by
the yT metabolite 2, 7, 8-trimethyl-2S-(.-carboxyethyl)-6-hydroxychroman (y-CEHC) which
requires hydroxylation of the y-methyl group of yT by cytochrome P450 (CYP450). In
carrageenan- induced inflammation in male Wistar rats, yT decreases prostaglandin (PGE2) and
leukotriene (LTB4) production, suggesting that 5-LO-mediated production of leukotrienes may
also be inhibited by yT. Tocopherols, including yT, also modulate gene expression of a number
of inflammatory genes. Thus, yT and other tocopherols decrease production of a number of
pro-inflammatory cytokines at the transcriptional level.

In animals, we have also shown that gamma tocopherol reduces baseline eosinophilia in the
airway. In our early phase I studies of gamma tocopherol-enriched mixed tocopherols (gT-mT)
we have shown that gT-mT inhibits monocyte induced cytokine production, decreases baseline
nitrosative stress, and inhibits LPS eosinophil and neutrophil influx in healthy volunteers.

SUMMARY:

There is widespread opinion that antioxidant nutrients like gamma tocopherol ( yT, a form of
Vitamin E) are an untapped and inexpensive intervention for environmentally triggered acute
asthma. However, there is a crucial gap in evidence-based support of such interventions in
asthma. A lack of coordinated research assessing specific antioxidant regimens from
preclinical, phase I and phase II studies impedes development of phase III antioxidant trials
in asthmatic populations. It is also unclear which physiological endpoints are most relevant
in such studies. This project focuses on phase II studies of yT in AA based on our
preclinical and phase I studies. For this protocol we will be testing the hypothesis that a
gamma tocopherol supplement will baseline eosinophil numbers in airway sputa of asthmatics
(specific aims 1) and (specific aim 2) inhibit LPS induced airway inflammation in mild
allergic asthmatics.

The investigators will also do an exploratory assessment of the specific impact of the GSTM1
null genotype on response to LPS and effect of gamma tocopherol enriched supplementation on
this response.

If gamma tocopherol decreases LPS-induced response in asthmatics, this would provide proof of
concept that this agent would be a useful intervention for asthma, confirming teh need for a
phase III study of gamma tocopherol enriched supplements as a treatment for asthma.

Inclusion Criteria:

1. Age 18-50 of both genders

2. Negative pregnancy test for females who are not s/p hysterectomy with oophorectomy

3. History of episodic wheezing, chest tightness, or shortness of breath consistent with
asthma, or physician diagnosed asthma.

4. Positive methacholine test. A positive test is defined as a provocative concentration
of methacholine of 10 mg/ml or less producing a 20% fall in Forced Expiratory Volume
in 1 second (FEV1) (PC20 methacholine) by the method used in a separate screening
protocol.

5. FEV1 of at least 80% of predicted and FEV1/FVC ratio of at least .70 (without use of
bronchodilating medications for 12 hours or long acting beta agonists for 24 hours),
consistent with lung function of persons with no more than mild episodic or mild
persistent asthma.

6. Allergic sensitization to at least one of the following allergen preparations: (House
Dust Mite f, House dust mite p, Cockroach, Tree mix, Grass Mix, Weed Mix, Mold Mix 1,
Mold Mix 2, Rat, Mouse, Guinea Pig, Rabbit, Cat or Dog) confirmed by positive
immediate skin test response.

7. Symptom Score (this will be submitted as an attachment) no greater than 16 (out of a
possible 24) for total symptom score with a value no greater than 3 for any one score.
No more than one score may be greater or equal than 3.

8. subjects must be willing to avoid caffeine for 12 hours prior to all visits.

Exclusion Criteria:

1. Any chronic medical condition considered by the PI as a contraindication to the
exposure study including significant cardiovascular disease, diabetes, chronic renal
disease, chronic thyroid disease, history of chronic infections/immunodeficiency,
history of tuberculosis

2. Physician directed emergency treatment for an asthma exacerbation within the preceding
12 months

3. Moderate or Severe asthma

4. Exacerbation of asthma more than 2x/week which would be characteristic of a person of
moderate or severe persistent asthma as outlined in the current NHLBI guidelines for
diagnosis and management of asthma.

5. Daily requirement for albuterol due to asthma symptoms (cough, wheeze, chest
tightness) which would be characteristic of a person of moderate or severe persistent
asthma as outlined in the current National Heart, Lung and Blood Institute (NHLBI)
guidelines for diagnosis and management of asthma. (Not to include prophylactic use of
albuterol prior to exercise).

6. Viral upper respiratory tract infection within 2 weeks of challenge.

7. Any acute infection requiring antibiotics within 2 weeks of exposure or fever of
unknown origin within 2 weeks of challenge.

8. Severe asthma

9. Mental illness or history of drug or alcohol abuse that, in the opinion of the
investigator, would interfere with the participant's ability to comply with study
requirements.

10. Medications which may impact the results of the Clinical Center Reference Endotoxin
(CCRE) exposure, interfere with any other medications potentially used in the study
(to include steroids, beta antagonists, non-steroidal anti-inflammatory agents)

11. Any history of smoking in the year prior to study enrollment; lifetime smoking history
> 10 pack years

12. Nighttime symptoms of cough or wheeze greater than 1x/week at baseline (not during a
clearly recognized viral induced asthma exacerbation) which would be characteristic of
a person of moderate or severe persistent asthma as outlined in the current NHLBI
guidelines for diagnosis and management of asthma

13. Allergy/sensitivity to study drugs, including E coli, or their formulations.

14. Known hypersensitivity to methacholine or to other parasympathomimetic agents

15. History of intubation for asthma

16. Unwillingness to use reliable contraception if sexually active (Intrauterine device,
birth control pills/patch, condoms).

17. Abnormal Prothrombin Time (PT) or Partial Thromboplastin Time (PTT) values at
screening or during the treatment period. Normal values will be those published by the
clinical lab (Labcorp, INC).

18. Any bleeding disorder

19. Radiation exposure history will be collected. Subjects whose exposure history within
the past twelve months would cause them to exceed their annual limits will be
excluded.

20. Pregnancy