Interaction between Ascorbate and Light-Exposed Riboflavin Induces Lung Remodeling

Vitamin C Regulates the Profibrotic Activity of Fibroblasts in In Vitro Replica Settings of Myocardial Infarction

Extracellular collagen remodeling is one of the central mechanisms responsible for the structural and compositional coherence of myocardium in patients undergoing myocardial infarction (MI). Activated primary cardiac fibroblasts following myocardial infarction are extensively investigated to establish anti-fibrotic therapies to improve left ventricular remodeling. To systematically assess vitamin C functions as a potential modulator involved in collagen fibrillogenesis in an in vitro model mimicking heart tissue healing after MI. Mouse primary cardiac fibroblasts were isolated from wild-type C57BL/6 mice and cultured under normal and profibrotic (hypoxic + transforming growth factor beta 1) conditions on freshly prepared coatings mimicking extracellular matrix (ECM) remodeling during healing after an MI. At 10 μg/mL, vitamin C reprogramed the respiratory mitochondrial metabolism, which is effectively associated with a more increased accumulation of intracellular reactive oxygen species (iROS) than the number of those generated by mitochondrial reactive oxygen species (mROS). The mRNA/protein expression of subtypes I, III collagen, and fibroblasts differentiations markers were upregulated over time, particularly in the presence of vitamin C. The collagen substrate potentiated the modulator role of vitamin C in reinforcing the structure of types I and III collagen synthesis by reducing collagen V expression in a timely manner, which is important in the initiation of fibrillogenesis. Altogether, our study evidenced the synergistic function of vitamin C at an optimum dose on maintaining the equilibrium functionality of radical scavenger and gene transcription, which are important in the initial phases after healing after an MI, while modulating the synthesis of de novo collagen fibrils, which is important in the final stage of tissue healing.

Dose-Response Effects of Glutathione Supplement in Parenteral Nutrition on Pulmonary Oxidative Stress and Alveolarization in Newborn Guinea Pig

In premature infants, glutathione deficiency impairs the capacity to detoxify the peroxides resulting from O₂ metabolism and those contaminating the parenteral nutrition (PN) leading to increased oxidative stress, which is a major contributor to bronchopulmonary dysplasia (BPD) development. In animals, the supplementation of PN with glutathione prevented the induction of pulmonary oxidative stress and hypoalveolarization (characteristic of BPD). Hypothesis: the dose of glutathione that corrects the plasma glutathione deficiency is sufficient to prevent oxidative stress and preserve pulmonary integrity. Three-day-old guinea pigs received a PN, supplemented or not with GSSG (up to 1300 µg/kg/d), the stable form of glutathione in PN. Animals with no handling other than being orally fed constituted the control group. After 4 days, lungs were removed to determine the GSH, GSSG, redox potential and the alveolarization index. Total plasma glutathione was quantified. The effective dose to improve pulmonary GSH and prevent the loss of alveoli was 330 µg/kg/d. A 750 µg/kg/d dose corrected the low-plasma glutathione, high-pulmonary GSSG and oxidized redox potential. Therefore, the results suggest that, in a clinical setting, the dose that improves low-plasma glutathione could be effective in preventing BPD development.

Recommendations for photoprotection of parenteral nutrition for premature infants: An ASPEN position paper

Although crucial in improving health outcomes in the preterm infants, parenteral nutrition (PN) is not without risk, especially if handled improperly. A growing body of evidence suggests that components of PN admixtures, including lipid injectable emulsions (ILEs), are susceptible to degradation, including oxidation when exposed to light (ie, photo-oxidation), resulting in the production of reactive oxygen species. Infants, especially those born preterm, are considered more susceptible to consequences of oxidative stress than children and adults. Oxidative stress is associated with bronchopulmonary dysplasia, retinopathy of prematurity, necrotizing enterocolitis, and intestinal failure-associated liver disease. The American Society for Parenteral and Enteral Nutrition (ASPEN) assembled a working group to provide recommendations on clinical practice surrounding photoprotection of PN.This Position Paper reviews the scientific literature on the formation of quantifiable peroxides and other degradation products when PN admixtures and ILEs are exposed to light and reports adverse clinical outcomes in premature infants exposed to PN. Recommendations for photoprotection of PN admixtures and ILEs are provided, as well as the challenges in achieving complete photoprotection with the equipment, supplies, and materials currently available in the US. ASPEN and the authors understand that the full implementation of complete photoprotection may not currently be feasible given current product availability; recommendations provided in this paper serve to represent the goal to which to strive as well as to highlight the importance of product availability to achieve these practices. This paper has been approved by the ASPEN Board of Directors.

Lichtschutz für Lösungen zur parenteralen Ernährung von Säuglingen und Kindern bis zum Alter von 2 Jahren

Das Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM) empfahl im Rote-Hand-Brief vom 02.09.2019: „Während der Verabreichung an Neugeborene und Kinder unter 2 Jahren sollen entsprechend zugelassene Arzneimittel zur parenteralen Ernährung (PE), die Aminosäuren und/oder Fettemulsionen enthalten, vor Licht geschützt werden (Behältnisse und Infusionsbestecke)“.

Ziel dieser Stellungnahme ist es, evidenzbasierte Empfehlungen zum Lichtschutz für Lösungen zu parenteraler und heimparenteraler Ernährung bei Säuglingen und Kindern bis zum Alter von 2 Jahren zu geben.

Der Bundesverband Deutscher Krankenhausapotheker, die Ernährungskommission der Deutschen Gesellschaft für Kinder- und Jugendmedizin, die Ernährungskommission der Österreichischen Gesellschaft für Kinder und Jugendheilkunde und die Arbeitsgemeinschaft Chronisches Darmversagen der Gesellschaft für Pädiatrische Gastroenterologie und Ernährung empfehlen in Übereinstimmung mit den internationalen Empfehlungen zur pädiatrischen parenteralen Ernährung der Fachgesellschaften ESPGHAN, ESPEN, ESPR und CSPEN: 1. Parenterale Nährlösungen, die Fette und/oder Vitamine enthalten, sind während der Applikation durch geeignete Maßnahmen vor Licht zu schützen. 2. Parenterale Nährlösungen, die keine Fette und/oder Vitamine enthalten (z. B. Lösungen mit Aminosäuren, Glucose, Elektrolyten oder Spurenelementen) bedürfen keines speziellen Lichtschutzes. 3. Bei heimparenteraler Ernährung können im Hinblick auf die kindlichen Bedürfnisse normale Spiralleitungen verwendet werden, solange lichtschützende Spiralleitungen nicht verfügbar sind.

Parenteral Nutrition and Oxidant Load in Neonates

Neonates with preterm, gastrointestinal dysfunction and very low birth weights are often intolerant to oral feeding. In such infants, the provision of nutrients via parenteral nutrition (PN) becomes necessary for short-term survival, as well as long-term health. However, the elemental nutrients in PN can be a major source of oxidants due to interactions between nutrients, imbalances of anti- and pro-oxidants, and environmental conditions. Moreover, neonates fed PN are at greater risk of oxidative stress, not only from dietary sources, but also because of immature antioxidant defences. Various interventions can lower the oxidant load in PN, including the supplementation of PN with antioxidant vitamins, glutathione, additional arginine and additional cysteine; reduced levels of pro-oxidant nutrients such as iron; protection from light and oxygen; and proper storage temperature. This narrative review of published data provides insight to oxidant molecules generated in PN, nutrient sources of oxidants, and measures to minimize oxidant levels.

Relationship between redox potential of glutathione and DNA methylation level in liver of newborn guinea pigs

The metabolism of DNA methylation is reported to be sensitive to oxidant molecules or oxidative stress. Hypothesis: early-life oxidative stress characterized by the redox potential of glutathione influences the DNA methylation level. The in vivo study aimed at the impact of modulating redox potential of glutathione on DNA methylation. Newborn guinea pigs received different nutritive modalities for 4 days: oral nutrition, parenteral nutrition including lipid emulsion Intralipid (PN-IL) or SMOFLipid (PN-SF), protected or not from ambient light. Livers were collected for biochemical determinations. Redox potential (p < 0.001) and DNA methylation (p < 0.01) were higher in PN-infused animals and even higher in PN-SF. Their positive correlation was significant (r² = 0.51; p < 0.001). Methylation activity was higher in PN groups (p < 0.01). Protein levels of DNA methyltransferase (DNMT)-1 were lower in PN groups (p < 0.01) while those of both DNMT3a isoforms were increased (p < 0.01) and significantly correlated with redox potential (r² > 0.42; p < 0.001). The ratio of SAM (substrate) to SAH (inhibitor) was positively correlated with the redox potential (r² = 0.36; p < 0.001). In conclusion, early in life, the redox potential value strongly influences the DNA methylation metabolism, resulting in an increase of DNA methylation as a function of increased oxidative stress. These results support the notion that early-life oxidative stress can reprogram the metabolism epigenetically. This study emphasizes once again the importance of improving the quality of parenteral nutrition solutions administered early in life, especially to newborn infants.

Abbreviation of Title: Parenteral nutrition and DNA methylation

Parenteral nutrition and oxidant stress in the newborn: A narrative review

There is strong evidence that oxidant molecules from various sources contaminate solutions of parenteral nutrition following interactions between the mixture of nutrients and some of the environmental conditions encountered in clinical practice. The continuous infusion of these organic and nonorganic peroxides provided us with a unique opportunity to study in cells, in vascular and animal models, the mechanisms involved in the deleterious reactions of oxidation in premature infants. Potential clinical impacts of peroxides infused with TPN include: a redox imbalance, vasoactive responses, thrombosis of intravenous catheters, TPN-related hepatobiliary complications, bronchopulmonary dysplasia and mortality. This is a narrative review of published data.

Oxygen and parenteral nutrition two main oxidants for extremely preterm infants: 'It all adds up'

OBJECTIVES

To assess the effect of early exposure to O2 and parenteral nutrition (PN) on oxidative stress at 36 weeks post-menstrual age (PMA) and on bronchopulmonary dysplasia (BPD) in extremely preterm infants.

STUDY DESIGN

A prospective observational study including 116 infants <29 weeks of gestation. Baseline clinical characteristics, FiO2 on day 7, duration of PN and clinical outcomes data were collected. In 39 infants, whole blood glutathione (GSH) and oxidized glutathione (GSSG) at 36 weeks PMA were measured and the redox potential was calculated using Nernst equation. Student's t-test, Chi-square, Spearman correlation, ANOVA, and logistic regression analyses were used as appropriate. P <  0.05 was considered significant.

RESULTS

FiO2 ≥25% was associated with higher level of GSSG (0.29 ± 0.04 versus 0.18 ± 0.02 nmol/mg of protein), a more oxidized redox potential (-191 ± 2 versus -198 ± 2 mV) and more BPD (90% versus 45%). PN duration >14 days was also associated with higher level of GSSG (0.26 ± 0.03 versus 0.13 ± 0.02 nmol/mg of protein), a more oxidized redox potential (-193 ± 5 versus -203 ± 2 mV) and more BPD (89% versus 24%). In logistic regression model, each 1% increase in FiO2 and each day increase in PN duration resulted in an increase in the OR for BPD by 1.57 (1.09 -2.28) and 1.17 (1.03 -1.33) respectively.

CONCLUSION

Early O2 supplement and PN have additive effects that were associated with prolonged oxidative stress and increased risk of BPD. Strategies targeting judicious use of O2 and decreasing the duration or developing a safer formulation of PN can be targeted to decrease BPD.

Adding glutathione to parenteral nutrition prevents alveolar loss in newborn Guinea pig

Bronchopulmonary dysplasia, a main complication of prematurity, is characterized by an alveolar hypoplasia. Oxidative stress is suspected to be a trigger event in this population who has a low level of glutathione, a main endogenous antioxidant, and who receives high oxidative load, particularly ascorbylperoxide from their parenteral nutrition.

HYPOTHESIS

the addition of glutathione (GSSG) in parenteral nutrition improves detoxification of ascorbylperoxide by glutathione peroxidase and therefore prevents exaggerated apoptosis and loss of alveoli.

METHODS

Ascorbylperoxide is assessed as substrate for glutathione peroxidase in Michaelis-Menten kinetics. Three-days old guinea pig pups were divided in 6 groups to receive, through a catheter in jugular vein, the following solutions: 1) Sham (no infusion); 2) PN(-L): parenteral nutrition protected against light (low ascorbylperoxide); 3) PN(+L): PN without photo-protection (high ascorbylperoxide); 4) 180 μM ascorbylperoxide; 5) PN(+L)+10 μM GSSG; 6) ascorbylperoxyde+10 μM GSSG. After 4 days, lungs were sampled and prepared for histology and biochemical determinations. Data were analysed by ANOVA, p < 0.05 RESULTS: The Km of ascorbylperoxide for glutathione peroxidase was 126 ± 6 μM and Vmax was 38.4 ± 2.5 nmol/min/ U. The presence of GSSG in intravenous solution has prevented the high GSSG, oxidized redox potential of glutathione, activation of caspase-3 (apoptosis marker) and loss of alveoli induced by PN(+L) or ascorbylperoxide.

CONCLUSION

A correction of the low glutathione levels observed in newborn animal on parenteral nutrition, protects lungs from toxic effect of ascorbylperoxide. Premature infants having a low level of glutathione, this finding is of high importance because it provides hope in a possible prevention of bronchopulmonary dysplasia.

Ascorbylperoxide from parenteral nutrition induces an increase of redox potential of glutathione and loss of alveoli in newborn guinea pig lungs

Background

Bronchopulmonary dysplasia is one of the main complications associated with extreme prematurity. Oxidative stress is suspected to be a trigger event of this lung disease, which is characterized by impaired alveolar development. Peroxides, mainly ascorbylperoxide and H₂O₂, are known contaminant of parenteral nutrition. We hypothesize that these oxidant molecules induce bronchopulmonary dysplasia development. The aim was to determine if the infusion of ascorbylperoxide, whether in presence or absence of H₂O₂, is associated with oxidative stress, apoptosis and loss of alveoli in the lungs of newborn guinea pigs.

Method

Three-day-old guinea pigs received parenteral solutions containing 0, 20, 60 or 180 µM ascorbylperoxide in the presence or not of 350 µM H₂O₂ (concentrations similar to those measured in parenteral nutrition). After 4 days, the lungs were collected for determination of glutathione's redox potential, caspase-3 activation (an apoptosis marker), alveolarization index (by histology), activation of Nrf2 and NF?B (biological markers of oxidative stress), and IL-6 and PGJ₂ levels (markers of NF?B activation). Groups were compared by ANOVA, p < 0.05.

Results

Loss of alveoli was associated with ascorbylperoxide in a dose-dependent manner, without an influence of H₂O₂. The dose-dependent activation of caspase-3 by ascorbylperoxide was lower in the presence of H₂O₂. Ascorbylperoxide induced an increase of redox potential in a dose-dependent manner, which reached a plateau in presence of H₂O₂. Nrf2 and NF?B were activated by H₂O₂ but not by ascorbylperoxide.

Conclusion

Results suggest that ascorbylperoxide, generated in parenteral nutrition, is involved in the development of bronchopulmonary dysplasia, independently of the increase of the redox potential. This study underlines the importance of developing a safer formulation of parenteral nutrition.

•

Oxidative stress is suspected to induce bronchopulmonary dysplasia.

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We investigate the role of ascorbylperoxide contaminating parenteral nutrition.

•

This molecule induces oxidation of redox potential, apoptosis and loss of alveoli.

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The alveolar loss is independent of the redox potential.

Characterizing dynamic regulatory programs in mouse lung development and their potential association with tumourigenesis via miRNA-TF-mRNA circuits

Background

In dynamic biological processes, genes, transcription factors(TF) and microRNAs(miRNAs) play vital regulation roles. Many researchers have focused on the transcription factors or miRNAs in transcriptional or post transcriptional stage, respectively. However, the transcriptional regulation and post transcriptional regulation is not isolated in the whole dynamic biological processes, there are few reserchers who have tried to consider the network composed by genes, miRNAs and TFs in this dynamic biological processes, especially in the mouse lung development. Moreover, it is widely acknowledged that cancer is a kind of developmental disorders, and some of pathways involved in tissue development might be also implicated in causing cancer. Although it has been found that many genes differentially expressed during mouse lung development are also differentially expressed in lung cancer, very little work has been reported to elucidate the combinational regulatory programs of such kind of associations.

Results

In order to investigate the association of transcriptional and post-transcriptional regulating activities in the mouse lung development, we define the significant triple relations among miRNAs, TFs and mRNAs as circuits. From the lung development time course data GSE21053, we mine 142610 circuit candidates including 96 TFs, 129 miRNAs and 13403 genes. After removing genes with little variation along different time points, we finally find 64760 circuit candidates, containing 8299 genes, 50 TFs, and 118 miRNAs in total. Further analysis on the circuits shows that the circuits vary in different stages of the lung development and play different roles. By investigating the circuits in the context of lung specific genes, we identify out the regulatory combinations for lung specific genes, as well as for those lung non-specific genes. Moreover, we show that the lung non-specific genes involved circuits are functionally related to the lung development. Noticing that some tissue developmental systems may be involved in tumourigenesis, we also check the cancer genes involved circuits, trying to find out their regulatory program, which would be useful for the research of lung cancer.

Conclusions

The relevant transcriptional or post-transcriptional factors and their roles involved in the mouse lung development are both changed greatly in different stages. By investigating the cancer genes involved circuits, we can find miRNAs/TFs playing important roles in tumour progression. Therefore, the miRNA-TF-mRNA circuits can be used in wide translational biomedicine studies, and can provide potential drug targets towards the treatment of lung cancer.

Neonatal exposure to oxidants induces later in life a metabolic response associated to a phenotype of energy deficiency in an animal model of total parenteral nutrition

Failure to protect total parenteral nutrition (TPN) from ambient light exacerbates the generation of peroxides, which affects blood glucose and plasma triacylglyceride (TG) in neonates. Based on the concept that the origin of adult diseases can be traced back to perinatal life, it was hypothesized that neonatal exposure to peroxides may affect energy availability later in life. Three-day-old guinea pigs, fitted with a jugular catheter, were fed regular chow (sham) +/- i.v. 350 microM H2O2 (sham + H2O2) or nourished with light-protected TPN [TPN(-)L, 209 +/- 9 microM peroxides] or light-exposed TPN [TPN(+)L, 365 +/- 15 microM peroxides]. After 4 d, infusions were stopped and animals fed chow. Spontaneous ambulatory movements, fasting blood glucose, glucose tolerance, TG, hepatic activities of glucokinase, phosphofructokinase (key enzymes of glycolysis), and acetyl-CoA carboxylase (key enzymes of lipogenesis) were determined at 12-14 wk and compared by ANOVA (p < 0.05). Relative to sham, the animals from sham + H2O2, TPN(-)L and TPN(+)L groups had lower plasma TG explained for 36% by low phosphofructokinase activity; they had lower glucose tolerance, lower body weight, and lower physical activity. In conclusion, neonatal exposure to oxidant molecules such as peroxides has important consequences later in life on lipid and glucose metabolism leading to a phenotype of energy deficiency.

Early life events, sex, and arterial blood pressure in critically ill infants

OBJECTIVE

To determine whether photo-protecting total parenteral nutrition in preterm infants influences arterial blood pressure differently according to gender. Blood pressure is influenced by complex mechanisms of vasomodulation. Oxidants are mediators and effectors in such reactions. Shielding total parenteral nutrition from light contributes to decrease the generation of peroxides. Girls may be better protected against an oxidant load than boys. We questioned whether shielding total parenteral nutrition may have cardiovascular effects that are influenced by gender.

DESIGN

A post hoc subgroup analysis of the effect of shielding parenteral nutrition from light.

SETTING

Neonatal intensive care unit.

SUBJECTS

Preterm infants <1000 g with indwelling arterial catheters who received light exposed (n = 20) or light protected (n = 20) parenteral nutrition.

INTERVENTIONS

Invasive monitoring, total parenteral nutrition.

MEASUREMENTS AND MAIN RESULTS

Arterial blood pressure was recorded hourly and compared between light exposed and light protected over the first week of life; timed average maximum velocity (m/s) was measured in the superior mesenteric artery by Doppler; presence of ductus arteriosus was documented by cardiac ultrasound. Data were analyzed by analysis of variance. No differences were noted between light exposed and light protected in clinical determinants that may influence blood pressure. There was an interaction (p < .01) between gender and total parenteral nutrition on blood pressure. In girls (n = 17), systolic and diastolic blood pressures were higher (p < .01) and heart rate lower (p < .01) during light exposed. There was no effect on BP observed in boys (n = 23). The linear correlation between timed average maximum velocity and systolic blood pressure was positive (p < .05). There was no echocardographic difference in hemodynamic variables between boys (n = 21) and girls (n = 9) who had a patent ductus.

CONCLUSION

Failure to shield total parenteral nutrition from light results in higher blood pressure in a selected population of critically ill female infants. This information adds to our understanding of the multiple determinants involved in optimizing arterial blood pressure in a critical care environment.

Effects of light exposure on total parenteral nutrition and its implications in the neonatal population

Total parenteral nutrition (TPN) is a necessary form of nutrition in neonates with functional or anatomical disruption of the digestive tract. However, laboratory and human investigation have shown that exposure of the TPN solution to light causes the formation of peroxides and other degradation products that are quantifiable in experimental TPN solutions, laboratory animals, and neonates. Premature neonates are at a higher risk for the development and progression of peroxide damage due to their relative lack of antioxidant and free radical scavenger reserves. Furthermore, cell damage seen in a number of neonatal disease states is exacerbated by the presence of peroxides that are generated via intrinsic pathologic processes and from exogenous sources such as TPN. Numerous studies show that the formation of TPN photodegradation products can be slowed or prevented by the application of various light protection mechanisms. While it is not yet known if minimizing TPN associated photodegradation byproducts has a significant direct effect on preventing or mitigating the overall clinical course of some neonatal disease states, it is becoming increasingly clear that light protecting TPN can avoid specific metabolic complications in neonatal patients. It is prudent to implement mechanisms that prevent photodegradation of TPN components from the manufacturer source to the point of patient administration.

Shielding parenteral nutrition from light: does the available evidence support a randomized, controlled trial?

BACKGROUND

Exposure of total parenteral nutrition to ambient light induces the generation of peroxides, creating oxidant stress, which potentially compounds complications of prematurity. Photograph protection of total parenteral nutrition reduces the peroxide load and has been shown to be associated with nutritional and biochemical benefits in animals and humans. It is unclear whether this reduction in peroxides from total parenteral nutrition leads to a reduction in the complications of prematurity, such as bronchopulmonary dysplasia. Our hypothesis was that shielding total parenteral nutrition from ambient light is linked to clinical benefits.

OBJECTIVE

The purpose of this work was to determine whether photograph protection of total parenteral nutrition (light protected), as compared with no photoprotection (light exposed), reduces the occurrence of bronchopulmonary dysplasia or death in preterm infants.

METHODS

The Canadian Neonatal Network provided data for infants born in 2006 at <28 weeks' gestation admitted to level 3 NICUs in Canada. A retrospective analysis was performed comparing bronchopulmonary dysplasia and death in infants who received light-exposed or light-protected parenteral nutrition. Data were analyzed by using logistic regression models. RESULTS. Thirteen NICUs offered partial light-protected (total parenteral nutrition bag only, intravenous tubing exposed) and 13 offered light-exposed parenteral nutrition; not a single NICU offered complete light-protected parenteral nutrition (total parenteral nutrition bag plus intravenous tubing). The incidence of bronchopulmonary dysplasia or death was 66% with light-protected (n = 428) vs 59% with light-exposed (n = 438) parenteral nutrition.

CONCLUSIONS

Partial photograph protection of total parenteral nutrition was not associated with a reduction in bronchopulmonary dysplasia or death as compared with no photograph protection; this relationship is confounded by covariates with strong associations with bronchopulmonary dysplasia. Partial photograph protection of total parenteral nutrition solutions confers no clinical benefit, while consuming valuable resources. A randomized, controlled trial is justified to determine whether there is a true "cause-and-effect" relationship between complete photoprotection of total parenteral nutrition and bronchopulmonary dysplasia or death.

Influence of lung oxidant and antioxidant status on alveolarization: role of light-exposed total parenteral nutrition

Parenteral multivitamins (MVP) are linked to the generation of peroxides, which cause oxidant injury in lungs associated with alveolar remodelling linked to lung disease of prematurity. This study was to investigate the relationship between alveolar development and lung oxidant-antioxidant status as modulated by the mode of administration of multivitamins with total parenteral nutrition (TPN). Four groups of guinea pig pups received parenteral nutrition differing by 1) mode of MVP admixture: with amino acid solution (AA-MVP) or lipid emulsion (LIP-MVP); 2) light exposure: TPN exposed (LE) or shielded from light (LP). After 2 or 4 days of TPN, vitamins C and E, 8-isoprostaneF2alpha and alveolarization index were determined in lungs and GSSG/GSH in lungs and blood. Exposure to light and the mode of MVP admixture did not influence vitamin E and isoprostane levels. Blood glutathione redox potential was more oxidized in LE and LIP-MVP groups after 4-day infusions, whereas lung redox potential was more reduced in LE groups. LP and LIP-MVP had a beneficial effect, with higher number of alveoli. Globally, results indicate that in this model, alveolarization and modifications in lung redox potential are two independent events induced by light exposed TPN.

In preterm neonates, is the risk of developing bronchopulmonary dysplasia influenced by the failure to protect total parenteral nutrition from exposure to ambient light?

Light-exposed total parenteral nutrition (TPN) generates peroxides that contribute to an oxidant load. Shielding TPN from light protects against lung remodelling. In preterm infants, photoprotection of TPN is associated with a 30% reduction in bronchopulmonary dysplasia in a post-hoc analysis. This analysis provides justification for a randomized controlled trial.

Effect of coadministration of parenteral multivitamins with lipid emulsion on lung remodeling in an animal model of total parenteral nutrition

Exposure of parenteral multivitamin solutions (MVP) to ambient light generates peroxides and vitamin loss, and induces initiation of fibrosis and a reduced alveolar count in an animal model of total parenteral nutrition (TPN). Adding MVP to the lipid moiety of TPN prevents lipid peroxidation and vitamin loss. The aim of the study was to compare modes of delivery of MVP on lung procollagen mRNA and alveolar counts. Three-day-old guinea pig pups were infused continuously with one of three intravenous solutions: 1) control = dextrose; 2) AA + MVP = MVP given with the dextrose + amino-acid moiety, in a "piggyback" setup with a lipid emulsion mixed close to the infusion site; and 3) LIP + MVP = same as AA + MVP, except that MVP is given with the lipid emulsion. After 4 days, lungs were prepared for alveolar count (intercept technique) and for quantification of the procollagen/beta-actin mRNA ratio (initial step of fibrosis). Data were compared by ANOVA. The procollagen mRNA was lower (P < 0.05) in animals receiving LIP + MVP than those with AA + MVP. But the two modes of admixture of MVP had the same effect on the alveolar counts, which were lower (P < 0.01) than controls. The mode of delivery of TPN affects lung remodeling. Although LIP + MVP protects against the initiation of lung fibrosis, the absence of a beneficial effect on alveolar counts suggests that these features of lung remodeling are not caused by a unique component of TPN. Specific roles of peroxides, components of MVP, and light exposure on lung remodeling need to be explored before LIP + MVP can be recommended as an alternative mode of parenteral vitamin delivery.