Borage and Echium Seed Oils for Asthma (Borage)

This study plans to look at whether borage and echium seed oils (natural oils from two plants) help decrease asthma symptoms and affect cells involved in inflammation. The investigators also want to look at how these plant oils decrease the generation of inflammatory cells in people with asthma.

To evaluate the mechanisms by which borage seed oil and echium seed oil block mediator generation in asthma, we performed a cross-over trial design to reduce the numbers of patients needed for the study. Each treatment period was six weeks with a six-week washout period. For simplicity all power calculations are made assuming a single factor or predictor variable and a single result or outcome variable. We focused on changes in mediator generation by effector cells. Calculations below suggest that we have resolution to pick up clinically meaningful effects of potentially important explanatory variables with acceptable or high power. 1. Study Design The goals were to examine the mechanisms that underlie the effects of borage seed oil and echium seed oil on proinflammatory mediator production by effector leukocytes. In the treatment arm, subjects consumed 4.0 g/day borage seed oil and 7.0 g/day echium seed oil (containing totals of ~1.6 g/day of GLA and ~0.9 g/day of SDA). The oils were packaged in capsules each of which contained 1 gram of oil. Therefore subjects will ingest 10 capsules a day (3 in the morning, 3 in the afternoon, and 4 in the evening) with meals. In the placebo arm, subjects took matching capsules containing corn oil; three 1 gram capsules in the morning and afternoon, and four in the evening, with meals. The study began with a screening visit. All subjects had physician-diagnosed asthma. All performed a baseline set of lung function measurements. They entered a 2-week run-in period during which they kept a diary of peak flows, asthma symptoms, and beta agonist use. Subjects were instructed in peak flow technique and asked to perform three maneuvers each time. The maneuver was considered technically sufficient if the variation in the values obtained on the three attempts are with 10% of each other, and the highest value was recorded in a diary. Subjects whose diaries were > 80% complete entered the study and were randomly assigned to active treatment or placebo. Spirometry was repeated. Blood was taken for fatty acid composition of plasma and leukocytes, LT generation, and DNA for genotyping at the LTC4S locus. Subjects were provided with peak flow diaries, instructed in the appropriate performance or peak flow maneuvers, and asked to record morning and evening peak flow each day (reflecting the best of three efforts each time). After three weeks of treatment, diary cards will be collected and spirometry repeated. After six weeks of treatment, blood was drawn for safety monitoring, for measurements of fatty acids in plasma and leukocytes, and for the functional analyses. Spirometry was repeated. Subjects then entered a six-week washout period. Two weeks before the end of this period they again started to keep diary cards. At the conclusion of the 6-week washout period they entered the cross-over treatment phase (six weeks) which followed the same protocol as the first treatment period with assessment of fatty acid analyses, cellular function studies, safety monitoring, and spirometry. Pregnancy testing was performed before and after each treatment period. Dairy cards (with peak flow monitoring results) will be collected at each visit (3 week intervals during the placebo and active treatment arms of the study). 3. Statistical Analyses a. Power Calculations - For simplicity all power calculations are made assuming a single factor or predictor variable and a single result or outcome variable. While a number of correlated outcomes will be investigated, we will focus on changes in mediator generation and levels of enzyme expression. Calculations below suggest that we have resolution to pick up clinically meaningful effects of potentially important explanatory variables with acceptable or high power. i. Biochemical Endpoints - Power is based on paired t-tests comparing continuous measures of response between treatment and placebo. We assume 40 subjects will be available after allowing for a drop out rate of 20% from our original sample of 50 subjects. For the endpoint of leukotriene production by leukocytes, the power calculations suggested that we will have 80% power to detect a true within-subject difference of 0.8 of the within-subject SD between treatment and placebo with an α value of 0/05. On the basis of our previous studies, we assume a within-subject coefficient of variation (CV) of 13% for LTC4 generation. This will translate to an approximate detectable difference from 10.5% in these parameters.Using a paired two-sided t-test and prior mean(standard deviation) estimates for the placebo of .001464 ( .002268) and for the borage oil of .000289( .000709) , we would need 40subjects for 80-90% power at a 0.05 level of significance to detect a change in LTC4S transcript, protein, and enzymatic activity of 50% between placebo and borage arms. b. Analysis Plan - Initially, we will present descriptive statistics (mean, standard deviation, range) for all endpoints to treatment and placebo groups. We will also present graphical plots of all measures across the study and for each group within each period. For the 2x2 crossover study, we will compare the treatment and control on each endpoint separately by employing a generalized mixed model approach with the predictors: group(sequence), patient nested within group as a random effect, period(dichotomous), treatment(dichotomous), and seasonality(dichotomous), with unstructured covariance. We will utilize mixed model diagnostics such as residual plots to assess goodness of fit.

Borage and echium oil capsules administered daily for six weeks, then a 6 week washout period, followed by ingestion of placebo (corn oil capsules) daily for 6 weeks.

Corn oil capsules daily for six weeks, then a 6 week washout period, followed by ingestion of Borage and echium oil capsules daily for 6 weeks.

4.0 g/day borage seed oil and 7.0 g/day echium seed oil. Pills will be taken three times per day for six weeks.

Primary outcome measures will be changes in the generation of LTC4 production by granulocytes. This was calculated by the difference between the amount produced at the start of each arm and at the end of each arm (i.e., two values were obtained in each arm and used to calculate the difference, and the differences were compared as a delta-delta).

Primary outcome measures will be changes in the generation of LTB4 production by granulocytes. This was calculated by the difference between the amount produced at the start of each arm and at the end of each arm (i.e., two values were obtained in each arm and used to calculate the difference, and the differences were compared as a delta-delta). A negative number implies that the level of LTB4 produced by granulocytes at the end of the arm was less than the amount produced at the start of the arm, while a positive number means that more was generated at the end than at the beginning.

Secondary outcome measures include changes in concentrations of omega 3 fatty acids in cell pellets, indicating incorporation of botanical oil metabolites in cell membrane lipids.. This was calculated by the difference between the amount present at the start of each arm and at the end of each arm (i.e., two values were obtained in each arm and used to calculate the difference, and the differences were compared as a delta-delta).

Changes in lung function (forced expiratory volume in 1 second) will be assessed via spirometry at each visit. This was calculated by the difference between the FEV1 at weeks 2 and 8 versus weeks 14 and 20. The differences were compared as a delta-delta. A negative number for this parameter means that the FEV1 was lower at the end of the arm than at the beginning, while a positive number means that the FEV1 was higher at the end.

Changes in plasma level of gamma linolenic acid (GLA), a major constituent of Borage oil, as a measure of compliance. This was calculated by the difference between the amount produced at the start of each arm and at the end of each arm (i.e., two values were obtained in each arm and used to calculate the difference, and the differences were compared as a delta-delta).

Changes in asthma control will be assessed via the Asthma Control Questionnaire (ACQ) at each visit. The ACQ is a 6-point questionnaire that reflects the degree of asthma activity. Each point is assigned a scale of 0-5, with 5 being the worst. Thus, the range is from 0 (no asthma symptoms) to 30 (severe asthma symptoms). For each arm, we generate two values (week 2 vs. week 8 and week 14 vs.week 20). These values are then averaged for each arm to obtain the final single value. A negative number implies improved symptoms.

Secondary outcome measures include changes in concentrations of omega 3 fatty acids in cell pellets, indicating incorporation of botanical oil metabolites in cell membrane lipids.. This was calculated by the difference between the amount present at the start of each arm and at the end of each arm (i.e., two values were obtained in each arm and used to calculate the difference, and the differences were compared as a delta-delta).

Differences in LTC4S activity while receiving borage/echium oils versus corn oil stratified by LTC4S genotype. We analyzed the genotype for 32 subjects for the borage arm and 30 subjects for the placebo arm.

Genotype-specific Differences in Change in Lung Function While Receiving Borage and Echium Oils Versus Corn Oil.

FEV1 was measured in all subjects at the beginning and end of both study arms. Subjects were genotyped at LTC4S locus and those bearing at least one A to C polymorphism were compared with those bearing two A alleles.

Inclusion Criteria: Male or female 18 years to 65 years of age Stable physician diagnosed asthma with FEV1 of greater than 50% of predicted but less than 90% of predicted or less than 90% of known best and an asthma control questionnaire(ACQ) < 1.5. Exclusion Criteria: Pregnant or nursing Smoking history of > 10 pack years or active smoking within the past year. Due to possible effects on LT biosynthesis, use of the following asthma treatments within the preceding month will be exclusion criteria: LT modifying drugs (zileuton, montelukast, zafirlukast) theophylline oral steroids dietary supplements with fatty acids or other products that may interfere with LT generation. Treatment within the previous three months with omalizumab (monoclonal antibody directed against IgE) Subjects will not be permitted to take non-steroidal anti-inflammatory drugs in the week prior to any measurements of ex vivo LT generation because of their effects on LT biosynthesis via inhibition of prostaglandin generation. A history of aspirin-sensitive asthma will be an exclusion criterion as the effects of GLA/SDA on prostanoid biosynthesis have not been adequately elucidated. Significant abnormalities in CBC, differential white cell count, renal function, and liver function, or urinalysis. No subjects will have any serious co-morbid medical condition.