Microwave observations reveal the deep extent and structure of Jupiter's atmospheric vortices

[Figure: see text].

Impact of Carotenoid Cleaving Enzymes on Lycopene Accumulation in Transgenic Mice

Objectives

To evaluate the role of β-carotene oxygenase 1 (BCO1) and BCO2 on lycopene tissue distribution.

Methods

Three-week old C57BL/6 male and female mice (wild type [WT], Bco1−/−, Bco2−/−, Bco1−/− × Bco2−/− double knock out [DKO]) were divided into groups based on genotype (n = 16 per group split evenly by sex) and fed a powdered AIN 93G control diet for 2 weeks. After this period, mice were gavaged daily for 2 weeks with 1 mg of lycopene dissolved in cottonseed oil. 12 h-fasted mice were then sacrificed, and liver, serum, heart, kidney, intestine, gonadal adipose, prostate, spleen, and testes were harvested. Tissues were preserved in liquid nitrogen and stored at −80 until analyses. We measured lycopene levels in all samples by using high-performance liquid chromatography. Data analyses were performed using two-way ANOVA, followed by the Sidaks test with a statistical significance threshold of P < 0.05.

Results

Female mice showed higher lycopene levels in the intestine (P < 0.045) and liver (P < 0.007) irrespective of genotype, while male mice had higher lycopene levels in serum (P < 0.004). Intestine, serum, and kidneys exhibited higher lycopene levels in DKO mice compared to all other genotypes (P < .0001), while having higher lycopene levels in testes (P < 0.0001) compared to Bco2−/− and WT mice and adipose (P < 0.005) only in comparison to Bco2−/− mice. DKO exhibited higher lycopene levels in the spleen compared to Bco1−/− mice (P < 0.02). Lycopene levels in the liver (P < 0.0001) were higher in Bco2−/− mice compared to Bco1 −/− and DKO mice, while Bco1−/− mice had lower hepatic lycopene levels compared to all other genotypes.

Conclusions

Female mice accumulated higher lycopene levels in most tissues compared to males. These results were consistent when data were corrected by total tissue weight. The data suggest the absence of BCO2 favors carotenoid accumulation in many extrahepatic tissues, an effect that is enhanced in the absence of both carotenoid cleaving enzymes.

Funding Sources

Internal funding, University of Illinois Urbana Champaign.

Lycopene: A Critical Review of Digestion, Absorption, Metabolism, and Excretion

Lycopene is a non-provitamin A carotenoid that exhibits several health benefits. Epidemiological data support a correlation between lycopene intake and the attenuation of several chronic diseases, including certain types of cancers and cardiovascular diseases. It is currently unknown whether the beneficial effects are from the native structure of lycopene or its metabolic derivatives: lycopenals, lycopenols, and lycopenoic acids. This literature review focuses on the current research on lycopene digestion, absorption, metabolism, and excretion. This review primarily focuses on in vivo studies because of the labile nature and difficulty of studying carotenoids within in vitro experimental models. The studies presented address tissue accumulation of lycopene, the modification of bioavailability due to genetic and dietary factors, and lycopene cleavage by the enzymes ß-carotene oxygenase 1 (BCO1) and ß-carotene oxygenase 2 (BCO2). The current literature suggests that the majority of lycopene is cleaved eccentrically by BCO2, yet further research is needed to probe the enzymatic cleavage activity at the tissue level. Additionally, results indicate that single nucleotide polymorphisms and dietary fat influence lycopene absorption and thus modify its health effects. Further research exploring the metabolism of lycopene, the mechanisms related to its health benefits, and optimal diet composition to increase the bioavailability is required.