Neonatal intrahepatocellular lipid

Quantification of fetal organ volume and fat deposition following in utero exposure to maternal Western Diet using MRI

PURPOSE

To examine the feasibility of using MRI to identify differences in liver size and fat deposition in fetal guinea pigs exposed to an in utero environment influenced by maternal consumption of a Western diet.

MATERIALS AND METHODS

Female guinea pigs fed either an energy-dense Western Diet (WD), comprised of increased saturated fats and simple sugars, or a Control Diet (CD) from weaning through pregnancy, underwent MR scanning near term (~ 60 days; term ~ 69 days). Maternal weights were collected at mating and at MR scanning. T1-weighted, T2-weighted, and IDEAL water-fat images were acquired at 3 Tesla. The images were used to segment maternal adipose tissue, fetal liver, fetal brain, fetal adipose tissue, and total fetal volumes and to measure maternal and fetal hepatic fat fractions.

RESULTS

Weights of WD sows were lower prior to pregnancy (P = .04), however their weight gain over pregnancy did not differ from the CD group (P = .98). The WD sows had less total adipose tissue (TAT) at MR scanning (P = .04), while hepatic fat content was significantly elevated (P = .04). When controlling for litter size, WD fetuses had larger livers (P = .02), smaller brains (P = .01), and increased total adipose tissue volume (P = .01) when normalized by fetal volume. The WD fetuses also had increased hepatic fat fractions compared to CD fetal livers (P < .001).

CONCLUSION

Maternal Western Diet consumption prior to and during pregnancy induces differences in maternal liver fat content, fetal liver volume and liver fat storage, as well as changes in fetal adipose tissue deposition that can be measured in utero using MRI.

Preterm infants have significantly longer telomeres than their term born counterparts

There are well-established morbidities associated with preterm birth including respiratory, neurocognitive and developmental disorders. However several others have recently emerged that characterise an 'aged' phenotype in the preterm infant by term-equivalent age. These include hypertension, insulin resistance and altered body fat distribution. Evidence shows that these morbidities persist into adult life, posing a significant public health concern. In this study, we measured relative telomere length in leukocytes as an indicator of biological ageing in 25 preterm infants at term equivalent age. Comparing our measurements with those from 22 preterm infants sampled at birth and from 31 term-born infants, we tested the hypothesis that by term equivalent age, preterm infants have significantly shorter telomeres (thus suggesting that they are prematurely aged). Our results demonstrate that relative telomere length is highly variable in newborn infants and is significantly negatively correlated with gestational age and birth weight in preterm infants. Further, longitudinal assessment in preterm infants who had telomere length measurements available at both birth and term age (n = 5) suggests that telomere attrition rate is negatively correlated with increasing gestational age. Contrary to our initial hypothesis however, relative telomere length was significantly shortest in the term born control group compared to both preterm groups and longest in the preterm at birth group. In addition, telomere lengths were not significantly different between preterm infants sampled at birth and those sampled at term equivalent age. These results indicate that other, as yet undetermined, factors may influence telomere length in the preterm born infant and raise the intriguing hypothesis that as preterm gestation declines, telomere attrition rate increases.

Nutritional Evaluation and Optimisation in Neonates: a randomized, double-blind controlled trial of amino acid regimen and intravenous lipid composition in preterm parenteral nutrition

BACKGROUND

Parenteral nutrition is central to the care of very immature infants. Current international recommendations favor higher amino acid intakes and fish oil-containing lipid emulsions.

OBJECTIVE

The aim of this trial was to compare 1) the effects of high [immediate recommended daily intake (Imm-RDI)] and low [incremental introduction of amino acids (Inc-AAs)] parenteral amino acid delivery within 24 h of birth on body composition and 2) the effect of a multicomponent lipid emulsion containing 30% soybean oil, 30% medium-chain triglycerides, 25% olive oil, and 15% fish oil (SMOF) with that of soybean oil (SO)-based lipid emulsion on intrahepatocellular lipid (IHCL) content.

DESIGN

We conducted a 2-by-2 factorial, double-blind, multicenter randomized controlled trial.

RESULTS

We randomly assigned 168 infants born at <31 wk of gestation. We evaluated outcomes at term in 133 infants. There were no significant differences between Imm-RDI and Inc-AA groups for nonadipose mass [adjusted mean difference: 1.0 g (95% CI: -108, 111 g; P = 0.98)] or between SMOF and SO groups for IHCL [adjusted mean SMOF:SO ratio: 1.1 (95% CI: 0.8, 1.6; P = 0.58]. SMOF does not affect IHCL content. There was a significant interaction (P = 0.05) between the 2 interventions for nonadipose mass. There were no significant interactions between group differences for either primary outcome measure after adjusting for additional confounders. Imm-RDI infants were more likely than Inc-AA infants to have blood urea nitrogen concentrations >7 mmol/L or >10 mmol/L, respectively (75% compared with 49%, P < 0.01; 49% compared with 18%, P < 0.01). Head circumference at term was smaller in the Imm-RDI group [mean difference: -0.8 cm (95% CI: -1.5, -0.1 cm; P = 0.02)]. There were no significant differences in any prespecified secondary outcomes, including adiposity, liver function tests, incidence of conjugated hyperbilirubinemia, weight, length, mortality, and brain volumes.

CONCLUSION

Imm-RDI of parenteral amino acids does not benefit body composition or growth to term and may be harmful. This trial was registered at www.isrctn.com as ISRCTN29665319 and at eudract.ema.europa.eu as EudraCT 2009-016731-34.

Continuous parenteral and enteral nutrition induces metabolic dysfunction in neonatal pigs

BACKGROUND

We previously showed that parenteral nutrition (PN) compared with formula feeding results in hepatic insulin resistance and steatosis in neonatal pigs. The current aim was to test whether the route of feeding (intravenous [IV] vs enteral) rather than other feeding modalities (diet, pattern) had contributed to the outcome.

METHODS

Neonatal pigs were fed enterally or parenterally for 14 days with 1 of 4 feeding modalities as follows: (1) enteral polymeric formula intermittently (FORM), (2) enteral elemental diet (ED) intermittently (IEN), (3) enteral ED continuously (CEN), and (4) parenteral ED continuously (PN). Subgroups of pigs underwent IV glucose tolerance tests (IVGTT) and hyperinsulinemic-euglycemic clamps (CLAMP). Following CLAMP, pigs were euthanized and tissues collected for further analysis.

RESULTS

Insulin secretion during IVGTT was significantly higher and glucose infusion rates during CLAMP were lower in CEN and PN than in FORM and IEN. Endogenous glucose production rate was suppressed to zero in all groups during CLAMP. In the fed state, plasma glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide (GLP)-1, and GLP-2 were different between feeding modalities. Insulin receptor phosphorylation in liver and muscle was decreased in IEN, CEN, and PN compared with FORM. Liver weight was highest in PN. Steatosis and myeloperoxidase (MPO) activity tended to be highest in PN and CEN. Enterally fed groups had higher plasma GLP-2 and jejunum weight compared with PN.

CONCLUSIONS

PN and enteral nutrition (EN) when given continuously as an elemental diet reduces insulin sensitivity and the secretion of key gut incretins. The intermittent vs continuous pattern of EN produced the optimal effect on metabolic function.

Disparity in circulating adiponectin multimers between term and preterm infants

AIMS

To study circulating levels and distribution of adiponectin multimers [low molecular weight (LMW)-, medium molecular weight (MMW)- and high molecular weight (HMW)-adiponectin] in preterm and full-term infants.

METHODS

Total serum adiponectin and its multimers were measured in 40 healthy infants at the age of one month and associations with anthropometric parameters [body weight and length, body mass index (BMI)], weight gain and metabolic indices (glucose, insulin) were examined. Twenty of the infants were born preterm (gestational age 33.2+/-1.6 weeks).

RESULTS

LMW-adiponectin level and its fractional ratio to total adiponectin were significantly higher in full-term than in preterm infants (P<0.001 and P<0.01, respectively), whereas, MMW-adiponectin level and its ratio were significantly lower (P=0.03 and P=0.01, respectively). HMW-adiponectin did not differ significantly between full-term and preterm infants and accounted for almost 60% of total adiponectin levels in both groups. HMW-adiponectin, but not MMW adiponectin or LMW adiponectin, correlated significantly with anthropometric measurements, similarly to total adiponectin; in addition, HMW adiponectin correlated significantly with weight gain.

CONCLUSIONS

HMW adiponectin is the most prevalent form in infants. Circulating levels and distribution of MMW- and LMW-adiponectin differ between full-term and preterm infants, but the role of these adiponectin multimers needs to be studied further.