Regulation of Nutrient Transport across the Placenta

Table 2

Factors altered in pregnancy complications and their effect on placental nutrient transport.

Factor	Pregnancy complication	Amino acids	Fatty acids	Glucose	Refs.
CRH	↑ IUGR (f); ↑ SGA (m)	↓ System A		↑ GLUT1; ↓ GLUT3	[61, 73–75]
Glucose	↑ GDM (m)	↑ System L; ↓ Taurine		↓ Uptake	[46, 76, 77]
IGF-I	↓ IUGR (m); ↑ LGA (f)	↑ System A	↓ LPL activity		[21, 46, 78–80]
IL-6	↑ Obesity (m)	↑ System A	↑ Lipid accumulation		[47, 81, 82]
Insulin	↑ LGA (f)**; ↑ GDM (m)	↑ System A; ↑ System L	↑ LPL activity*	↑ Uptake*	[21, 43–46, 79, 83–86]
Leptin	↑ LGA (f); ↑ IUGR (m); ↑ Obesity (m); ↑ GDM (m)	↑ System A	↑ FAT		[21, 43, 45, 77, 82, 85, 87, 88]
Lipids	↑ GDM (m); ↑ Obesity (m)	↑ System A	↓ LPL activity; ↑ FABP4/5		[48, 77, 89–91]
mTOR	↓ IUGR (p); ↑ Obesity (p)	↑ System A; ↑ System L; ↑ Taurine			[46, 50, 53, 54]
Oxidative stress	↑ IUGR	↓ Taurine		↓ Uptake	[65, 92–94]

Increased (↑), decreased (↓), and unchanged (↔) circulatory levels or placental activity/expression of nutrient transporters in pregnancies with IUGR or fetal overgrowth as compared to normally grown fetuses. Factors altered in maternal (m) circulation, fetal (f) circulation, or placenta (p). The effect of listed factors on the activity or expression of nutrient transporters has been determined in vitro in term placenta. SGA: small for gestational age. *Conflicting findings have been reported; see text for discussion. **Conflicting findings have been reported; for instance see [95].