Impact of shielding parenteral nutrition from light on routine monitoring of blood glucose and triglyceride levels in preterm neonates
ABSTRACT Premature infants are vulnerable to complications related to oxidative stress. Exposure to light increases oxidation products in solutions of total parenteral nutrition (TPN) such as lipid peroxides and hydrogen peroxide. Oxidative stress impairs glucose uptake and affects lipid metabolism. Hypothesis: products of photo-oxidation contaminating TPN affect lipid metabolism.
Evaluate the effect of photoprotection of TPN in preterm infants on plasma glucose and triglyceride (TG) concentrations.
Secondary analysis of a prospective study allocating preterm infants to light-exposed (LE, n = 32) or light-protected (LP, n = 27) TPN.
Level III NICU referral centre for patients of British Columbia.
Preterm infants requiring TPN. Interventions and
TG and blood glucose measured during routine monitoring while on full TPN were compared between LE and LP.
Clinical characteristics were similar between the two groups (gestational age 28+/-1 wk; birth weight: 1.0+/-0.1 kg). Nutrient intakes from TPN and from minimal enteral nutrition were comparable between LE and LP. Blood glucose was higher in preterm infants receiving LE (p<0.001). The accumulation of TG with increasing lipid intake was twice as high with LE accounting for significantly higher TG levels on days 8 and 9 (p<0.05).
Failure to photoprotect TPN may cause alterations in intermediary metabolism. Shielding TPN from light provides a potential benefit for preterm infants by avoiding hypertriglyceridaemia allowing for increased substrate delivery.
- SourceAvailable from: Wesam Elremaly
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- "The capacity of newborns to detoxify peroxides seems insufficient since the introduction of multivitamin preparations in parenteral nutrition, which contain ascorbate, is associated with increased concentrations of peroxides in their urine  . Reduction of peroxide levels in parenteral nutrition is associated in newborn preterm infants with a reduced incidence of chronic lung diseases  such as bronchopulmonary dysplasia  as well as modifications in glucose and lipid metabolism  and blood pressure . Glutathione is a key molecule in the antioxidant defense system. "
ABSTRACT: Premature newborn infants on total parenteral nutrition (TPN) are at risk of oxidative stress because of peroxides contaminating TPN and low glutathione level. Low cysteine availability limits glutathione synthesis. In this population, the main source of cysteine derives from the hepatic conversion of methionine. The first enzyme of this conversion, methionine adenosyltransferase (MAT), contains redox sensitive cysteinyl residues. We hypothesize that inhibition of MAT by peroxides contaminating TPN leads to a lower availability of cysteine for glutathione synthesis. At 3 days of life, animals were fitted with a jugular catheter for intravenous infusion. Four groups were compared by ANOVA (p<0.05): 1) Control: without surgery, fed regular chow; 2) Sham: fitted with an obstructed catheter, fed orally regular chow; 3) TPN: fed exclusively TPN (dextrose, amino acids, fat, vitamins) containing 350μM peroxides; 4) H(2)O(2): fed regular chow orally and infused with 350μM H(2)O(2). Four days later, MAT activity and glutathione in liver and blood were lower in TPN and H(2)O(2) groups. The redox potential was more oxidized in blood and liver of the TPN group. In conclusion, peroxides generated in TPN inhibit methionine adenosyltransferase activity with, among consequences, a low level of glutathione and a more oxidized redox potential.Free Radical Biology and Medicine 10/2012; 53(12). DOI:10.1016/j.freeradbiomed.2012.10.541 · 5.71 Impact Factor
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- "The infusion of oxidized lipids and secondary peroxidation products can be extremely cytotoxic, and may cause many disorders, such as hepatic steatosis , hyper triglyceridemia , increase in vascular resistance in the lung [17,38], lung remodeling  and chronic lung diseases of prematurity [40,41]. TPN is a potential source of oxidants and this is particularly dangerous in preterm infants who are vulnerable to oxidative stress [42,43]. "
ABSTRACT: Preterm infants need high amounts of calcium and phosphorus for bone mineralization, which is difficult to obtain with parenteral feeding due to the low solubility of these salts. The objective of this study was to evaluate the physicochemical compatibility of high concentrations of calcium associated with organic phosphate and its influence on the stability of AIO admixtures for neonatal use. Three TPN admixture formulas were prepared in multilayered bags. The calcium content of the admixtures was adjusted to 0, 46.5 or 93 mg/100 ml in the presence of a fixed organic phosphate concentration as well as lipids, amino acids, inorganic salts, glucose, vitamins and oligoelements at pH 5.5. Each admixture was stored at 4 degrees C, 25 degrees C or 37 degrees C and evaluated over a period of 7 days. The physicochemical stability parameters evaluated were visual aspect, pH, sterility, osmolality, peroxide formation, precipitation, and the size of lipid globules. Color alterations occurred from the first day on, and reversible lipid film formation from the third day of study for the admixtures stored at 25 degrees C and 37 degrees C. According to the parameters evaluated, the admixtures were stable at 4 degrees C; and none of them presented precipitated particles due to calcium/phosphate incompatibility or lipid globules larger than 5 mum, which is the main parameter currently used to evaluate lipid emulsion stability. The admixtures maintained low peroxide levels and osmolarity was appropriate for parenteral administration. The total calcium and calcium/phosphorus ratios studied appeared not to influence the physicochemical compatibility and stability of AIO admixtures.Nutrition Journal 10/2009; 8:51. DOI:10.1186/1475-2891-8-51 · 2.64 Impact Factor
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