Deficiency of carnitine and its amino acids precursors in newborn infants with intrapartum hypoxia

Abstract

The myocardial hypoxia ischemia is related to an accumulation of long chain

acylcamitines (LC) in the myocites sarcolemma improving profound alterations in the

gap junctional conductance. Similar alterations are also observed in newbom infants

with intrapartum asphyxia showing important derangements of the electrophysiological

conductance during the neonatal periodo We analyze markers of "insufficiency" and

"deficiency" of camitine (C) and its arnino acids precursors [lysine (LYS) and methionine

(MET)] in newbom infants at the first days of life, 39 with intrapartum hypoxia (G-

1) and 35 normal neonates (control group) (G-I1). Free (FC) and total (TC) camitine

and short chain (SC) and LC acy1camitines were measured using a radioisotopic

method; Amino acids L YS and MET were obtained by HPLC. SC, LC and TC plasma

concentrations and LCIFC and SC+LCIFC ratio s were significantly higher in G-I than

in G-I1. FC/TC was lower in G-I than in G-I1. The 59% of G-I in front of 31 % of GIl

(p<0.05) had a "C-deficiency" (FC/TC<0.7). The SC+LC/FC ratio was >0.7 ("Cinsufficiency")

in 59% of G-I and 28% in G-I1 (p<0.01). In G-I1, MET was correlated

with FC/TC (r:0.50) and SC+LC/FC (r:-0.45) were demonstrated. There were significant

in verse correlation between FC, SC, LC, TC, LCIFC, SC+LCIFC and pHua (n:74) (r:-

0.26-p<0.05; r:-0.43-p<0.01 ; r:-0 .34-p<0.01 ; r:-0.42-p<0.01; r:-0.30-p<0.05; r:-0.40-

p<O.OI, respectively). FC/TC and MET were directly correlated with pHua (n:74)

(r:0.33-p<0.01; r:0.24-p<0.05, respectively). So, we conc1ude that: 1) an important

percentage of hypoxic neonates have during the first days of life a "C-deficiency" and

"C-insufficiency", and this fact is related to MET plasma levels; 2)The degree of "Cdeficiency"

and "C-insufficiency" is determined by the acidosis degree.