Pharmacokinetics of Benzo[a]Pyrene: Impact of Diet

Study Overview
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Brief Summary
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Evaluation of the pharmacokinetics for [14C]-benzo[a]pyrene ([14C]-BaP) and metabolites in plasma and urine over 48 hours following a 50 ng dose (5.4 nCi) alone, following 7 days' consumption of Brussels sprouts, and following 7 days' consumption of a supplement containing 3,3'-diindolylmethane (DIM).

Detailed Description
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The pharmacokinetics for [14C]-BaP and metabolites will be assessed by UHLPC-Accelerator Mass Spectrometry (AMS, Lawrence Livermore National Laboratory) in plasma and urine collected over 48 hours following oral doses of 50 ng dose (5.4 nCi) alone, following 7 days' consumption of Brussels sprouts, and following 7 days' consumption of a supplement containing 3,3'-diindolylmethane (DIM). The investigators hypothesize that pre-administration of Brussels sprouts or DIM will alter [14C]-BaP metabolism and increase the rate of elimination consistent with predictions based on a previously developed Physiologically-Based Pharmacokinetic (PBPK) model for BaP. Briefly, this hypothesis will be tested by dosing individuals with 50 ng [14C]-BaP alone and, following a 3-week washout period, ingestion of about 50 g Brussels sprouts or 300 mg of 3,3'-diindolylmethane (DIM) supplement for 7 days prior to the [14C]-BaP micro-dose. The impact of the supplement and the whole food will be assessed with respect to alterations in uptake from the GI tract, metabolism and rate of elimination. The consumption of cruciferous vegetables will be assessed at the beginning of the study by completion of a dietary questionnaire to examine typical eating patterns in the previous 3 months and by collection and extraction of blood and urine to assay for DIM by LC/ESI-MS/MS-SRM). In addition, for each phase, urine will be assayed for DIM as an estimate of crucifer or DIM supplement intake. In preclinical and clinical studies, administration of Brussels sprouts or DIM impacts the activity of the same enzymes responsible for the phase 1 (CYP1A1 and CYP1B1) and phase 2 enzymes (GSTM1, UGT, SULT). Monitoring changes in β-estradiol metabolites will confirm the mechanism of alteration in the metabolic profile of [14C]-BaP. Metabolite profiles and kinetics of elimination are predicted to be consistent with a BaP physiologically based pharmacokinetic (PBPK) model developed by Pacific Northwest National Laboratory (PNNL). A non-smoker, not exposed occupationally, receives 270-700 ng of BaP daily; about 95% dietary. The WHO has set an estimated safe daily lifetime (70 year/70 Kg individual, cancer endpoint) exposure to BaP of 42-350 ng. This protocol represents de minimus risk.

Official Title
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Pharmacokinetics of Benzo[a]Pyrene: Impact of Diet

Conditions
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Environmental Exposure

Intervention / Treatment
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* Drug: [14C]-benzo[a]pyrene
* Drug: Brussels sprouts before 50 ng dose
* Drug: DIM supplement before 50 ng dose


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 21-65 (inclusive) If female, must be post-menopausal or have had surgical sterilization to eliminate any possibility for fetal exposure Willing to defer blood donation for one month before, throughout, and one month after completion of study activities Willing to avoid consuming cruciferous vegetables, I3C or DIM supplements, smoked or cured meat or cheeses, or charcoal-grilled meats for 2 weeks prior to and during each study cycle (gas grilled foods acceptable) Health history review and physical assessment showing general good health, as determined by study physician. Acceptable physical exam may have been conducted as part of protocol 8233 or 8554 if subject has not had significant changes in health status. Exclusion Criteria: Smoker (tobacco or other substances) or use of smokeless tobacco in past 3 months or living with smoker Regular use of medications that affect gut motility or nutrient absorption (e.g. cholestyramine, sucralfate, orlistat, pro- or anti-motility agents) History of gastrointestinal surgery (e.g. bariatric surgery, cholecystectomy) or gastrointestinal disorder (Crohn's disease, celiac disease, IBS, or colitis) Current or history of kidney or liver disease Prior high-dose 14C exposure from medical tests. (micro-dose 14C exposure not exclusionary) Occupational PAH exposure (e.g. roofers, asphalt pavers, fire-fighters, etc.) Regular use of indole-3-carbinol or DIM dietary supplements Allergy or intolerance to Brussels sprouts or similar foods

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 50 ng dose<br>Capsule containing 50 ng (5.4 nCi) [14C]-benzo[a]pyrene (BaP) | Drug: [14C]-benzo[a]pyrene<br>* Oral micro-dose (50 ng) (5.4 nCi)<br>* Other names: Carcinogenic PAH environmental pollutant;|
| Experimental: Brussels sprouts before 50 ng dose<br>Subjects will consume 50 g (about 1/2 cup) of lightly steamed Brussels sprouts each evening for 7 days prior to taking capsule containing 50 ng (5.4 nCi) [14C]-benzo[a]pyrene (BaP) | Drug: Brussels sprouts before 50 ng dose<br>* Brussels sprouts for 7 days before 50 ng (5.4 nCi) dose of BaP<br>* Other names: Brussels sprouts and carcinogenic PAH;|
| Experimental: DIM supplement before 50 ng dose<br>Subjects will consume 300 mg DIM supplement ( 2 capsules of BioResponse DIM® 150) each evening for 7 days prior to taking capsule containing 50 ng (5.4 nCi) [14C]-benzo[a]pyrene (BaP). A 300 mg DIM dose will be co-administrated with the 50 ng BaP dose | Drug: DIM supplement before 50 ng dose<br>* DIM supplement for 7 days before 50 ng (5.4 nCi) dose of BaP and coadministration with DIM supplement<br>* Other names: Cruciferous vegetable supplement and carcinogenic PAH;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma and urine 14C-BaP and 14C-BaP metabolite levels after oral dose | Plasma and urine levels of 14C-BaP and 14C-BaP metabolites measured by accelerator mass spectrometry | 48 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Peak plasma concentration of 14C-BaP Cmax | Determination of highest concentration of 14C-BaP in plasma | 48 hours | 
| Time at highest plasma concentration of 14C-BaP Tmax | Determination of time at which plasma concentration of 14C-BaP is highest | 48 hours | 
| Area under plasma concentration of 14C-BaP versus time curve AUC | Integration of concentration of 14C-BaP in plasma over time | 48 hours | 
| Rate of elimination of 14C-BaP | Determination of constants for rate of elimination of 14C-BaP from plasma | 48 hours | 
| Metabolites of 14C-BaP in plasma | Determination of plasma metabolites of 14C-BaP | 48 hours | 
| Metabolites of 14C-BaP in urine | Determination of urinary metabolites of 14C-BaP | 48 hours | 
| Metabolites of B-estradiol in urine | Determination of urinary metabolites of B-estradiol | -7 days and 48 hours | 
| Metabolites of B-estradiol in plasma | Determination of plasma metabolites of B-estradiol | -7 days and 48 hours | 
| Metabolites of DIM in plasma | Determination of plasma metabolites of DIM | -7 days and 48 hours | 
| Metabolites of DIM in urine | Determination of urinary metabolites of DIM | -7 days and 48 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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I3C, PAH, Benzo[a]pyrene, Accelerator Mass Spectrometry, Polycyclic Aromatic Hydrocarbons, cruciferous vegetable, Brussels sprouts, 3,3'-diindolylmethane, DIM, indole-3-carbinol