Dataset Information

Total Adipose Retinol Concentrations Are Correlated with Total Liver Retinol Concentrations in Male Mongolian Gerbils, but Only Partially Explained by Chylomicron Deposition Assessed with Total ?-Retinol.

ABSTRACT:

Background

Liver vitamin A (VA) concentration is the gold standard for VA status, but is not routinely accessible. Adipose tissue VA concentrations, as retinol and retinyl esters, may be correlated to liver VA. ?-VA (as ?-retinol) is a cleavage product of ?-carotene that traces postprandial VA distribution to tissues but cannot recirculate from hepatic stores, providing insight into tissue VA sources.

Objective

We performed a secondary analysis of VA and ?-VA in Mongolian gerbil liver and adipose to determine the suitability of adipose tissue VA as a biomarker of VA status.

Methods

Gerbils (n = 186) consumed feeds containing 0-15.9 ?g (0-55.6 nmol) retinol activity equivalents/g as preformed VA and/or provitamin A carotenoids for 36-62 d in 3 studies. Body fat percentage was determined in the final study by MRI. Serum and liver retinol, ?-retinol, and retinyl esters were extracted and analyzed by HPLC or ultra-performance LC (UPLC). Epididymal and retroperitoneal adipose tissue retinol and ?-retinol were determined by UPLC after homogenization, saponification, and extraction. Linear regression models with appropriate data transformations identified determinants of adipose VA concentrations.

Results

Liver VA did not predict serum retinol concentrations. After logarithmic transformation of adipose and liver values, liver VA positively predicted both adipose depots' VA concentrations (P < 0.001, R ² > 0.7). Adding serum retinol or body fat percentage did not significantly increase the adjusted R ². In liver, ?-VA concentration explained much of the variation of VA (P < 0.001, R ² > 0.7), but far less in epididymal and retroperitoneal adipose (P = 0.004 and 0.012, respectively, R ² < 0.4).

Conclusions

Adipose VA is correlated with liver VA and is a potential biomarker of VA status. It is not fully explained by chylomicron deposition and is negatively affected by serum retinol. Adipose biopsy validation is needed for human applications.

SUBMITTER: Sheftel J

PROVIDER: S-EPMC6377429 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature

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Total Adipose Retinol Concentrations Are Correlated with Total Liver Retinol Concentrations in Male Mongolian Gerbils, but Only Partially Explained by Chylomicron Deposition Assessed with Total α-Retinol.

Sheftel Jesse J Sowa Margaret M Mourao Luciana L Zoué Lessoy T LT Davis Christopher R CR Simon Philipp W PW Tanumihardjo Sherry A SA

Current developments in nutrition 20190208 2

<h4>Background</h4>Liver vitamin A (VA) concentration is the gold standard for VA status, but is not routinely accessible. Adipose tissue VA concentrations, as retinol and retinyl esters, may be correlated to liver VA. α-VA (as α-retinol) is a cleavage product of α-carotene that traces postprandial VA distribution to tissues but cannot recirculate from hepatic stores, providing insight into tissue VA sources.<h4>Objective</h4>We performed a secondary analysis of VA and α-VA in Mongolian gerbil l ...[more]

PMID: 30793096

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Project description:BackgroundVitamin A (VA) deficiency is a public health problem in some countries. Fortification, supplementation, and increased provitamin A consumption through biofortification are efficacious, but monitoring is needed due to risk of excessive VA intake when interventions overlap.ObjectivesTwo studies in 28-36-d-old male Mongolian gerbils simulated exposure to multiple VA interventions to determine the effects of provitamin A carotenoid consumption from biofortified maize and carrots and preformed VA fortificant on status.MethodsStudy 1 was a 2 × 2 × 2 factorial design (n = 85) with high-β-carotene maize, orange carrots, and VA fortification at 50% estimated gerbil needs, compared with white maize and white carrot controls. Study 2 was a 2 × 3 factorial design (n = 66) evaluating orange carrot and VA consumption through fortification at 100% and 200% estimated needs. Both studies utilized 2-wk VA depletion, baseline evaluation, 9-wk treatments, and liver VA stores by HPLC. Intestinal scavenger receptor class B member 1 (Scarb1), β-carotene 15,15'-dioxygenase (Bco1), β-carotene 9',10'-oxygenase (Bco2), intestine-specific homeobox (Isx), and cytochrome P450 26A1 isoform α1 (Cyp26a1) expression was analyzed by qRT-PCR in study 2.ResultsIn study 1, liver VA concentrations were significantly higher in orange carrot (0.69 ± 0.12 μmol/g) and orange maize groups (0.52 ± 0.21 μmol/g) compared with baseline (0.23 ± 0.069 μmol/g) and controls. Liver VA concentrations from VA fortificant alone (0.11 ± 0.053 μmol/g) did not differ from negative control. In study 2, orange carrot significantly enhanced liver VA concentrations (0.85 ± 0.24 μmol/g) relative to baseline (0.43 ± 0.14 μmol/g), but VA fortificant alone (0.42 ± 0.21 μmol/g) did not. Intestinal Scarb1 and Bco1 were negatively correlated with increasing liver VA concentrations (P < 0.01, r2 = 0.25-0.27). Serum retinol concentrations did not differ.ConclusionsBiofortified carrots and maize without fortification prevented VA deficiency in gerbils. During adequate provitamin A dietary intake, preformed VA intake resulted in excessive liver stores in gerbils, despite downregulation of carotenoid absorption and cleavage gene expression.