Transcriptomics does not show adverse effects of beta-carotene in A/J mice exposed to smoke for 2 weeks.

Beta-carotene (betaC) supplementation in smokers was unexpectedly associated with increased incidence of lung cancer versus smoking alone. We performed a study in A/J mice to explore possible betaC/cigarette smoke (CS) interactions potentially influencing lung cancer risk in smokers. A/J mice received a diet containing 120 or 600 ppm betaC for six weeks, and exposed to mainstream CS (140 mg total suspended particulates/m(3)) during the last two weeks.

beta-carotene-induced changes in RARbeta isoform mRNA expression patterns do not influence lung adenoma multiplicity in the NNK-initiated A/J mouse model.

A number of epidemiological studies have reported associations of beta-carotene plasma levels or intake with decreased lung cancer risk. However, intervention studies in smokers reported increased lung tumor rates after high long-term beta-carotene supplementation. For insight into these conflicting results, we studied the influence of beta-carotene on tobacco smoke carcinogen-induced lung cancer development in the A/J-mouse using 4-(N-Methyl-N-nitro samino)-1-(3-pyridyl)-1-butanone (NNK) as the initiator and lung adenoma multiplicity as the functional endpoint.

Transformations of selected carotenoids in plasma, liver, and ocular tissues of humans and in nonprimate animal models.

Purpose: To determine the stereochemistry of carotenoids in human ocular tissues in comparison with plasma and liver and to elucidate the possible transformations of dietary (3R,3'R,6'R)-lutein and (3R,3'R)-zeaxanthin in the eye. Similarly, to characterize the carotenoid profiles in the eye tissues, plasma, and liver of quails and frogs to determine whether these can serve as appropriate nonprimate animal models for metabolic studies.

Methods: Configurational isomers of carotenoids and their nondietary by-products from pooled human plasma, liver, retinal pigment epithelium (RPE-choroid), ciliary body, iris, and lens were characterized and quantified by high-performance liquid chromatography (HPLC) on a chiral column.

Plasma concentration response to drinks containing beta-carotene as carrot juice or formulated as a water dispersible powder.

Background: Bioavailability of beta-carotene is highly variable and depends on the source, the formulation and other nutritional factors.

Objective: It was the aim of the study to compare beta-carotene plasma response to b-carotene dosing with two commercially available drinks, containing beta-carotene from carrot juice or as water dispersible beta-carotene powder. Design In a randomized, parallel group study design, 4 volunteers per group received daily beta-carotene doses of 6-7 or 18-22 mg of either drink over 6 weeks.