TY - JOUR
T1 - Dietary Iron Repletion Stimulates Hepatic Mobilization of Vitamin A in Previously Iron-Deficient Rats as Determined by Model-Based Compartmental Analysis
AU - Li, Yaqi
AU - Wei, Cheng Hsin
AU - Green, Michael H.
AU - Ross, A. Catharine
N1 - Funding Information:
Supported by The Pennsylvania State University Graduate Program in Nutritional Sciences and NIH HD-066982. Author disclosures: The authors report no conflicts of interest. Address correspondence to ACR (e-mail: acr6@psu.edu). Abbreviations used: CN, control group; FDp, fraction of the injected dose in plasma; FSD, fractional SD; ID–, iron-deficient group; ID+, iron-repletion group; VA, vitamin A; WinSAAM, Windows version of the Simulation, Analysis, and Modeling software.
Publisher Copyright:
Copyright © The Author(s) on behalf of the American Society for Nutrition 2020.
PY - 2020/7/1
Y1 - 2020/7/1
N2 - Background: Iron deficiency can result in hyporetinolemia and hepatic vitamin A (VA) sequestration. Objectives: We used model-based compartmental analysis to determine the impact of iron repletion on VA metabolism and kinetics in iron-deficient rats. Methods: At weaning, Sprague-Dawley rats were assigned to either a VA-marginal diet (0.35 mg retinol equivalent/kg) with adequate iron (35 ppm, control group [CN]) or reduced iron (3 ppm, iron-deficient group [ID-]), with an equivalent average body weight for each group. After 5 wk, n = 4 rats from each group were euthanized for baseline measurements of VA and iron indices, and the remaining rats (n = 6 CN, n = 10 ID-) received an intravenous injection of 3H-labeled retinol in an emulsion as tracer to initiate the kinetic study. On day 21 after dosing, half of the ID- rats were switched to the CN diet to initiate iron repletion, referred to as the iron-repletion group (ID+). From the time of dosing, 34 serial blood samples were collected from each rat over a 92-d time course. Plasma tracer and tissue tracee data were fitted to 6- and 4-compartment models, respectively, to analyze the kinetic behavior of VA in all groups. Results: Our mathematical model indicated that ID- rats exhibited a nearly 6-fold decrease in liver VA secretion and >4-fold reduction in whole-body VA utilization, compared with CN rats, whereas these perturbed kinetic behaviors were notably corrected in ID+ rats, close to those from the CN group. Conclusions: Iron repletion can remove the inhibitory effect that iron deficiency exerts on hepatic mobilization of VA and restore retinol kinetic parameters to values similar to that of never-deficient CN rats. Together with improvements in iron and VA indices, our results suggest that restoration of an iron-adequate diet is sufficient to improve VA kinetics after a previous state of iron deficiency.
AB - Background: Iron deficiency can result in hyporetinolemia and hepatic vitamin A (VA) sequestration. Objectives: We used model-based compartmental analysis to determine the impact of iron repletion on VA metabolism and kinetics in iron-deficient rats. Methods: At weaning, Sprague-Dawley rats were assigned to either a VA-marginal diet (0.35 mg retinol equivalent/kg) with adequate iron (35 ppm, control group [CN]) or reduced iron (3 ppm, iron-deficient group [ID-]), with an equivalent average body weight for each group. After 5 wk, n = 4 rats from each group were euthanized for baseline measurements of VA and iron indices, and the remaining rats (n = 6 CN, n = 10 ID-) received an intravenous injection of 3H-labeled retinol in an emulsion as tracer to initiate the kinetic study. On day 21 after dosing, half of the ID- rats were switched to the CN diet to initiate iron repletion, referred to as the iron-repletion group (ID+). From the time of dosing, 34 serial blood samples were collected from each rat over a 92-d time course. Plasma tracer and tissue tracee data were fitted to 6- and 4-compartment models, respectively, to analyze the kinetic behavior of VA in all groups. Results: Our mathematical model indicated that ID- rats exhibited a nearly 6-fold decrease in liver VA secretion and >4-fold reduction in whole-body VA utilization, compared with CN rats, whereas these perturbed kinetic behaviors were notably corrected in ID+ rats, close to those from the CN group. Conclusions: Iron repletion can remove the inhibitory effect that iron deficiency exerts on hepatic mobilization of VA and restore retinol kinetic parameters to values similar to that of never-deficient CN rats. Together with improvements in iron and VA indices, our results suggest that restoration of an iron-adequate diet is sufficient to improve VA kinetics after a previous state of iron deficiency.
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U2 - 10.1093/jn/nxaa098
DO - 10.1093/jn/nxaa098
M3 - Article
C2 - 32297934
AN - SCOPUS:85087470291
VL - 150
SP - 1982
EP - 1988
JO - Journal of Nutrition
JF - Journal of Nutrition
SN - 0022-3166
IS - 7
ER -