The autophagy reaction in the human umbilical cord: a potential marker for estimating fetal nutrition and neonatal growth

To assess the induction of autophagy in the human umbilical cord for physiological adaptation against starvation. The expression of autophagy-related proteins (LC3-II, p62) in umbilical cord tissues from 40 neonates was assessed by Western blotting. The correlation between the expression of autophagy-related proteins and maternal findings (height, weight, body mass index [BMI]), placental weight, neonatal findings (gestational age, height, weight, Apgar score at 1 min and 5 min), and the pH of the umbilical arterial blood were analyzed using Spearman’s rank correlation coefficient test (<i>p</i> values of &lt;.05 were considered significant). Venous blood findings (pH, pCO₂, glucose, total protein, albumin, and lactic acid) were also evaluated in 16 neonates admitted to the NICU. The expression of LC3-II was positively correlated with serum total protein (<i>ρ</i> = 0.564, <i>p</i> = .023). The p62 level was also correlated with maternal BMI (<i>ρ</i> = 0.376, <i>p</i> = .017), the neonatal Apgar score at 1 min (<i>ρ</i> = 0.331 <i>p</i> = .037), total protein (<i>ρ</i> = 0.588, <i>p</i> = .017), and albumin (<i>ρ</i> = 0.552, <i>p</i> = .027) positively. A multiple linear regression analysis that included clinical parameters related to fetal nutrition and neonatal growth revealed that serum total protein was significantly associated with both LC3-II (<i>p</i> = .024) and p62 (<i>p</i> = .034) in the umbilical cord. The LC3-II or p62 expression in the umbilical cord may suggest the autophagy reaction for the homeostasis of protein or amino acid metabolism in the perinatal period.