BACKGROUND: Inflammation, both acute and chronic, is associated with reductions in the synthesis of retinol-binding protein (RBP) and the concentration of retinol in plasma. Consequently, it is currently recommended that the retinol isotope dilution (RID) method not be used to estimate vitamin A total body stores (TBS) in subjects with inflammation. OBJECTIVES: To apply compartmental analysis to study the effects of inflammation on hepatic apo-RBP input, plasma retinol pool size, and RID-predicted TBS in theoretical subjects with known steady state values for these parameters. METHODS: We selected 6 previously generated hypothetical subjects who ingested a dose of stable isotope-labeled vitamin A (day 0). Starting with each subject's published steady state model for retinol tracer kinetics, we developed a parallel model for unlabeled retinol and RBP that incorporated links between these entities and tied liver retinol secretion to RBP availability. Then we perturbed the steady state model by initiating chronic or acute inflammation on day 0 or acute inflammation on day 3 or 9 and simulating results for RBP, plasma retinol, and TBS. RESULTS: Chronic inflammation led to substantial reductions in RID-predicted TBS for at least 2 weeks after tracer administration. In contrast, acute inflammation induced on day 0 or 3 resulted in less dramatic impacts on TBS (37% or 20% reduction, respectively, from steady state levels, with levels rebounding by 14 days). When inflammation was induced 9 days after administration of the tracer, the effects on predicted TBS were minimal. Overall, for acute inflammation initiated at 0, 3, or 9 days, accurate predictions of TBS were obtained by 2 weeks. CONCLUSIONS: Compartmental analysis can be applied in the novel way described here to study the influence of perturbations such as inflammation on predictions of vitamin A status using RID. Such an approach has potential value for studying other perturbations and different nutrients.
BACKGROUND:Inflammation, both acute and chronic, is associated with reductions in the synthesis of retinol-binding protein (RBP) and the concentration of retinol in plasma. Consequently, it is currently recommended that the retinol isotope dilution (RID) method not be used to estimate vitamin A total body stores (TBS) in subjects with inflammation. OBJECTIVES: To apply compartmental analysis to study the effects of inflammation on hepatic apo-RBP input, plasma retinol pool size, and RID-predicted TBS in theoretical subjects with known steady state values for these parameters. METHODS: We selected 6 previously generated hypothetical subjects who ingested a dose of stable isotope-labeled vitamin A (day 0). Starting with each subject's published steady state model for retinol tracer kinetics, we developed a parallel model for unlabeled retinol and RBP that incorporated links between these entities and tied liver retinol secretion to RBP availability. Then we perturbed the steady state model by initiating chronic or acute inflammation on day 0 or acute inflammation on day 3 or 9 and simulating results for RBP, plasma retinol, and TBS. RESULTS: Chronic inflammation led to substantial reductions in RID-predicted TBS for at least 2 weeks after tracer administration. In contrast, acute inflammation induced on day 0 or 3 resulted in less dramatic impacts on TBS (37% or 20% reduction, respectively, from steady state levels, with levels rebounding by 14 days). When inflammation was induced 9 days after administration of the tracer, the effects on predicted TBS were minimal. Overall, for acute inflammation initiated at 0, 3, or 9 days, accurate predictions of TBS were obtained by 2 weeks. CONCLUSIONS: Compartmental analysis can be applied in the novel way described here to study the influence of perturbations such as inflammation on predictions of vitamin A status using RID. Such an approach has potential value for studying other perturbations and different nutrients.
Authors: Georg Lietz; Harold C Furr; Bryan M Gannon; Michael H Green; Marjorie Haskell; Veronica Lopez-Teros; Janet A Novotny; Amanda C Palmer; Robert M Russell; Sherry A Tanumihardjo; Carolien A Van Loo-Bouwman Journal: Food Nutr Bull Date: 2016-04-06 Impact factor: 2.069
Authors: Jennifer Lynn Ford; Joanne Balmer Green; Marjorie J Haskell; Shaikh M Ahmad; Dora Inés Mazariegos Cordero; Anthony Oxley; Reina Engle-Stone; Georg Lietz; Michael H Green Journal: J Nutr Date: 2020-02-01 Impact factor: 4.798
Authors: Emmanuel K Aklamati; Modest Mulenga; Stephen R Dueker; Bruce A Buchholz; Janet M Peerson; Emmanuel Kafwembe; Kenneth H Brown; Marjorie J Haskell Journal: J Nutr Date: 2010-07-21 Impact factor: 4.798
Authors: Marjorie J Haskell; Kazi M Jamil; Ferdaus Hassan; Janet M Peerson; M Iqbal Hossain; George J Fuchs; Kenneth H Brown Journal: Am J Clin Nutr Date: 2004-09 Impact factor: 7.045
Authors: H C Furr; O Amedee-Manesme; A J Clifford; H R Bergen; A D Jones; D P Anderson; J A Olson Journal: Am J Clin Nutr Date: 1989-04 Impact factor: 7.045
Authors: Michael H Green; Jennifer Lynn Ford; Joanne Balmer Green; Philip Berry; Alan V Boddy; Anthony Oxley; Georg Lietz Journal: J Nutr Date: 2016-08-10 Impact factor: 4.798
Authors: Rachel M Burke; Ralph D Whitehead; Janet Figueroa; Denis Whelan; Anna M Aceituno; Paulina A Rebolledo; Rita Revollo; Juan S Leon; Parminder S Suchdev Journal: Nutrients Date: 2018-09-05 Impact factor: 5.717