Evaluation of expression of amino acid and fatty acid metabolic transporters in the placenta of pregnant women with glucose intolerance

Aim

Pregnant women with glucose intolerance often have large infants, even with strict glycemic control. We examined the expression of amino and fatty acid metabolic transporters in the placentas of such mothers to clarify the role of factors other than glucose transport resulting in giant infants.

Methods

Deliveries at our hospital between 2017 and 2022 were assessed. Immunohistochemical staining of membrane transporters related to glucose, amino acid, and fatty acid transport was performed using postpartum placental tissue. Stained areas were classified and scored, and compared using the Mann–Whitney U test. Multiple logistic regression analysis was performed for large for gestational age infant as the outcome and maternal age, prepartum body mass index, primipara/multipara, gestational week, and glucose intolerance as confounding factors.

Results

Among 1725 subjects, 101 met the inclusion criteria and were analyzed (glucose-intolerant [GI] group, n = 61; non-GI group, n = 40). Per unit villus, there was decreased expression of amino acid-related transporters. However, per unit placenta, the immunohistochemical staining scores for glucose, amino acid, and fatty acid transport were significantly higher in the GI than in the non-GI group. Multiple logistic regression analysis showed that L-type amino acid transporter 1 (LAT1, odds ratio [95% confidence interval]: 12.35 [2.93–52.05], p < 0.001) and placenta-plasma membrane fatty acid-binding protein (placenta-FABPpm, 6.27 [1.64–23.88], p = 0.007) were significantly higher in the GI than in the non-GI group.

Conclusion

Activation of LAT1 and placenta-FABPpm expressions observed in the placentas of glucose-intolerant women despite glycemic control indicate that nutrients other than blood glucose should also be effectively managed.