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DMT1 and FPN1 expression during infancy: developmental regulation of iron absorption
Weng-In Leong1, Christopher L Bowlus, Jonas Tallkvist
1Department of Nutrition, University of California, Davis, California 95616, USA.
Insights
Infant iron absorption mechanisms change with age. Early infancy shows different regulation than late infancy, which resembles adult iron transport regulation.
Area of Science:
- Physiology
- Developmental Biology
- Nutritional Science
Background:
- Divalent metal transporter 1 (DMT1) and ferroportin 1 (FPN1) are key iron transporters.
- Their specific roles in infant iron absorption remain largely uncharacterized.
Purpose of the Study:
- To investigate the expression and function of DMT1, FPN1, ferritin, and transferrin receptor in infant rats.
- To understand iron absorption regulation during early and late infancy under varying iron conditions.
Main Methods:
- Studied iron metabolism in iron-deficient and iron-supplemented rat pups at days 10 and 20.
- Quantified expression of DMT1, FPN1, ferritin, and transferrin receptor.
- Assessed body iron uptake, mucosal iron retention, and total iron absorption.
Main Results:
- In early infancy (day 10), FPN1 expression decreased significantly with iron deficiency, while DMT1 remained unchanged; iron absorption parameters were unaffected.
- In late infancy (day 20), iron deficiency led to a substantial increase in both DMT1 and FPN1 expression, enhancing iron uptake and absorption.
- Iron supplementation normalized transporter expression and iron absorption parameters in iron-deficient pups by day 20.
Conclusions:
- Iron absorption regulation in infant rats differs significantly between early and late infancy.
- Late infancy iron absorption mechanisms resemble those of adult animals, indicating developmental regulation.
- These findings highlight critical developmental changes in how infants manage iron uptake and utilization.
Abstract:
Two iron transporters, divalent metal transporter1 (DMT1) and ferroportin1 (FPN1) have been identified; however, their role during infancy is unknown. We investigated DMT1, FPN1, ferritin, and transferrin receptor expression, iron absorption and tissue iron in iron-deficient rat pups, iron-deficient rat pups given iron supplements, and controls during early (day 10) and late infancy (day 20). With iron deficiency, DMT1 was unchanged and FPN1 was decreased (-80%) at day 10. Body iron uptake, mucosal iron retention, and total iron absorption were unchanged. At day 20, DMT1 increased fourfold and FPN1 increased eightfold in the low-Fe group compared with controls. Body iron uptake and total iron absorption were increased, and mucosal iron retention was decreased with iron deficiency. Iron supplementation normalized expression levels of the transporters, body iron uptake, mucosal iron retention, and total iron absorption of the low-Fe group to those of controls at day 20. In summary, the molecular mechanisms regulating iron absorption during early infancy differ from late infancy when they are similar to adult animals, indicating developmental regulation of iron absorption.