Summary table of results in relation to literature data
| Family | Transporter | Protein Expression Profile Group | Literature Data: Age versus mRNA Expression | Literature Data: Age versus Protein Expression | Current Data: Postnatal Age versus Protein Expression | Current Data: Postmenstrual Age versus Protein Expression | Current Data: Intertransporter Correlation of Protein Expression |
|---|---|---|---|---|---|---|---|
| SLCO family | OATP1B1 | Profile I: stable | Low-high: With low expression in fetuses and infants up to 1 yr of age (n = 32) (Mooij et al., 2014), and low expression in fetal (n = 30) versus pediatric and adult samples (n = 30 each) (Burgess et al., 2015), and again lower mRNA expression in 3 fetuses than 3 adults (Sharma et al., 2013). | Stable: In neonates and adults (n = 10, Western blotting), expression was similar (Yanni et al., 2011). In 7–70 yr of age, OATP1B1 (n = 64, LC-MS/MS) protein expression was stable (Prasad et al., 2014). | Similar: PNA <3 mo versus adults | Stable from PMA 16.43 to 51.29 wk | ABCB1*, ABCC2*, BSEP**, ABCG2**, GLUT1* |
| Low-high: In children ageing 0–12 yr (n = 78, Western blotting), OATP1B1 protein expression was low from birth until 6 yr of age and increased thereafter (abstract only) (Thomson et al., 2013). | |||||||
| OATP2B1 | Low-high: OATP2B1 mRNA expression was lower in 3 fetuses from second trimester of pregnancy than in 3 adults (Sharma et al., 2013). | Stable: In 7–70 yr of age, OATP2B1 (n = 64, LC-MS/MS) protein expression was stable (Prasad et al., 2014). | Similar: PNA <3 mo versus adults | Stable from PMA 16.43 to 51.29 wk | |||
| ABC family | ABCB1 | Low-high: Increase during fetal life, continues postnatal to reach adult levels around 1 yr of age (van Kalken et al., 1992; Miki et al., 2005; Fakhoury et al., 2009; Mooij et al., 2014; Burgess et al., 2015). | Stable: Stable protein expression from 0.3 to 12 yr of age (n = 65, Western blotting, abstract only) (Tang et al., 2007) | Similar: PNA <3 mo versus adults | Stable from PMA 16.43 to 51.29 wk | MCT1* | |
| ABCC2 | Low-high: Fourfold higher in pediatric and adult than fetal liver samples (Burgess et al., 2015). Low ABCC2 mRNA expression up to 1 yr of age where it reaches adult levels (Mooij et al., 2014). | Low-high: Increasing protein expression in 0.3–12 yr of age (n = 65, Western blotting) (Tang et al., 2007). From 7 yr of age onward, stable expression (n = 51, LC-MS/MS) (Deo et al., 2012). | Similar: PNA <3 mo versus adults | Stable from PMA 16.43 to 51.29 wk | ABCB1**, GLUT1** | ||
| ABCC3 | Profile II: low to high | Low-high: ABCC3 mRNA expression was significantly lower in livers of 3 fetuses than 3 adults (Sharma et al., 2013) and in perinatal/neonatal (prenatal to postnatal day 30, n = 6; and 0–4 yr, n = 8) compared with older than 7-yr liver samples (Klaassen and Aleksunes, 2010). | Stable: In liver samples of neonates and adults (n = 10, Western blotting), ABCC3 protein expression was stable (Yanni et al., 2011). | Low-high | Low-high | ABCB1*, ABCC2**, GLUT1** | |
| BSEP | Low-high: BSEP mRNA expression increased from fetal (n = 3) to approximately threefold in adult (n = 3) livers; in another study, expression was lower in neonates than in children older than 7 yr (Klaassen and Aleksunes, 2010; Sharma et al., 2013). | BSEP protein was immunohistochemically detected in second trimester fetuses (Chen et al., 2005). | Low-high | Low-high | ABCB1**, ABCC2**, ABCC3**, GLUT1** | ||
| ABCG2 | Profile III: high to low | Stable: Stable ABCG2 mRNA expression was found; in fetal (n = 30, second trimester of pregnancy), pediatric (n = 30, age 1–17 yr), and adult (age 28–80 yr) liver samples and in a study comparing 3 fetal and 3 adult livers (Sharma et al., 2013; Burgess et al., 2015). | Stable: ABCG2 protein expression was stable in neonates and adult livers (n = 10, Western blotting) (Yanni et al., 2011). And in 7–70 yr of age, ABCG2 (n = 56, LC-MS/MS), protein expression was stable (Prasad et al., 2013). | High-low | High-low | OATP1B1**, OCTN2** | |
| ABCG2 protein immunohistochemistry staining showed weak coloring in first trimester fetal hepatocytes, whereas adult liver showed strong ABCG staining (Konieczna et al., 2011). | |||||||
| Solute carrier family | GLUT1 | High-low | High-low | OATP1B1*, ABCC2*, ABCC3**, BSEP**, ABCG2**, OCTN2** | |||
| OCTN2 | High-low | High-low | GLUT1**, ABCG2** | ||||
| MCT1 | Profile IV: nonlinear | Nonlinear | Low-high | ABCB1* |
PMA, postmenstrual age; PNA, postnatal age.
* P < 0.05, **P < 0.01.