Normal values of creatine kinase and of MB-creatine kinase at birth in healthy babies.

BACKGROUND: Today, few studies have been accomplished in order to determine serum creatine kinase (CK) activity in newborns by considering small groups of babies and without taking into account gestational age (GA) differences. Some authors have demonstrated that neonatal CK activity value at birth is higher than the normal range of CK activity considering for adults or older children. The objective of this study is to assess normal values of CK and MB-CK in neonatal blood, according to babies' GA. METHODS: We retrieved the clinical files of 140 babies admitted into Siena Hospital NICU in a 2-years period, when CK was assessed routinely to all babies at birth. We selected files from 114 newborns and we divided the cohort into group A (non-stressed; N.=41) and group B (stressed; N.=73) on the basis of Apgar Score and signs of neurological lesions. We compared CK and MB-CK values in the two groups according to GA. RESULTS: Mean CK value of the 41 non-stressed babies' samples: 413 IU/L (232 SD). CK significantly increases with GA. No differences are present in total CK activity between stressed vs. non-stressed babies; but a significant difference appears in these two groups for MB-CK (mean values: 456 vs. 175 IU/L). CONCLUSIONS: This is the first study that compares CK and MB-CK values at birth according to the GA of the babies. CK values increase with GA, and stressed babies have higher MB-CK values than the non-stressed babies. These reference values are important for clinical practice.

Breast milk: To each his own. From metabolomic study, evidence of personalized nutrition in preterm infants.

OBJECTIVES: The composition of milk from mothers delivering prematurely differs from that of full-term mature milk and changes over time. The aim of this study is to test the hypothesis that changes in milk metabolomic profile from mothers delivering prematurely persist over time when compared with mothers delivering at term. METHODS: Nuclear magnetic resonance spectroscopy was used to analyze the metabolome pattern of human milk samples collected from 18 mothers. Twelve mothers collected 12 term milk samples (one for each mother) once between 4 and 7 d after delivery. Six mothers delivering prematurely (29-31 wk of gestational age) and collected three samples each, once a week after delivery until the third week after birth. RESULTS: Principal component analysis identified two distinct metabolite groups, one represented by the 18 preterm milk samples and the other by term milk samples. Metabolite profiling identified that lactose and oligosaccharide levels were significantly more represented in preterm than in milk term samples. CONCLUSIONS: The preterm milk metabolome pattern undergoes maturation during the first 3 wk after birth, but at the end of the third week it still does not resemble the term milk pattern. The specific changes in mothers' milk metabolomic profiles according to their offspring might reflect the different nutritional requirement of each preterm infant. This knowledge is crucial to move from standardized nutritional protocols to tailored, individualized nutrition in preterm infants.

Oxygen Use in Neonatal Care: A Two-edged Sword.

In the neonatal period, the clinical use of oxygen should be taken into consideration for its beneficial and toxicity effects. Oxygen toxicity is due to the development of reactive oxygen species (ROS) such as OH• that is one of the strongest oxidants in nature. Of note, generation of ROS is a normal occurrence in human and it is involved in a myriad of physiological reactions. Anyway an imbalance between production of oxidant species and antioxidant defenses, called oxidative stress, could affect various aspect of organisms' physiology and it could determine pathological consequences to living beings. Neonatal oxidative stress is essentially due to decreased antioxidants, increased ROS, or both. Studies have demonstrated that antioxidant capacity is lower in preterm newborns than term babies. This well-known deficiency of antioxidant factors is only a piece of a cohort of factors, which can be involved in the neonatal oxidative stress and the increased production of ROS may be a main factor. Mechanisms of ROS generation are: mitochondrial respiratory chain, free iron and Fenton reaction, inflammation, hypoxia and/or ischemia, reperfusion, and hyperoxia. Oxidative stress following hyperoxia has been recognized to be responsible for lung, central nervous system, retina, red blood cell injuries, and possibly generalized tissue damage. When supplemental oxygen is needed for care, it would be prudent to avoid changes and fluctuations in SpO2. The definition of the safest level of oxygen saturations in the neonate remains an area of active research. Currently, on the basis of the published evidences, the most suitable approach would be to set alarm limits between 90 and 95%. It should allow to avoid SpO2 values associated with potential hypoxia and/or hyperoxia. Although the usefulness of antioxidant protection in the neonatal period is still under investigation, the risk of tissue damage due to oxidative stress in perinatal period should not be underestimated.