Redox status in very-low birth-weight newborns

Inborn metabolic diseases, such as disorders in pyruvate metabolism, in gluconeogenesis or in the respiratory chain, may present with lactic acidosis in newborn infants. A simple tool to screen for the efficacy of mitochondrial oxidation reduction activity is the detection of the redox status through simultaneous measurements of plasma lactate, pyruvate and ketone bodies, which are strongly influenced by feeding and stress. We present the redox status values of 55 very-low birth-weight infants under different nutritional conditions. We were able to demonstrate that the redox status values are not dependent on the type of nutrition (oral feeding or continuous enteral nutrition). Instead we observed a strong difference between newborns with intrauterine growth retardation and newborns with appropriate growth. Newborns with intrauterine growth retardation show lower preprandial values of glucose and ketone bodies than newborns with appropriate weight, but higher levels of lactate and pyruvate; nevertheless the lactate/pyruvate and beta-hydroxybutyrate/acetoacetate ratios are normal. The results of the redox status study could suggest the reduced activity of gluconeogenesis and, probably, of beta-oxidation in very-low birth-weight newborns with intrauterine growth retardation.