[Show abstract][Hide abstract] ABSTRACT: To test the hypothesis that total energy expenditure is significantly higher in extremely low birth weight (ELBW) infants compared with healthy term infants near the time of discharge.
This study was designed to determine total energy expenditure and body composition in a group of ELBW infants nearing discharge receiving full-volume enteral feedings of fortified breast milk or postdischarge formula (Neosure) (n = 10; mean birth weight, 0.8 +/- 0.1 kg; mean gestational age, 26 +/- 0.8 weeks; mean age at study, 68 +/- 9 days; mean postconceptional age, 36 +/- 1 weeks) and compare them with healthy term newborns all receiving breast milk (n = 14; mean birth weight, 3.5 +/- 0.5 kg; mean gestational age, 39.0 +/- 1.4 weeks; mean age at study, 2.3 +/- 1 days). Body composition and total energy expenditure were measured using the doubly labeled water method over a 7-day period.
Mean total energy expenditure was significantly higher in the ELBW infants compared with the term infants (89 +/- 22 kcal/kg/day vs 58 +/- 19 kcal/kg/day; P <or= .001). Total energy expenditure normalized to fat-free mass was also significantly greater in the ELBW infants (98 +/- 3 kcal/kg/day vs 73 +/- 20 kcal/kg/day; P <or= .01).
The rate of total energy expenditure is greater in ELBW infants nearing discharge compared with normal healthy term infants. In the ELBW infants, higher energy intake compensates for their higher total energy expenditure.
Preview · Article · Nov 2008 · The Journal of pediatrics
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to compare total energy expenditure (TEE) in extremely premature infants during and after an episode of sepsis. We hypothesized that TEE in the sepsis group (SEP) would be higher during the septic period and higher than an age-matched control group (CTL). We further hypothesized that the TEE of the SEP group during the recovery period would be similar to that of the CTL group. The doubly labeled water method was used to determine TEE in both groups. Infant characteristics were as follows: SEP group, n = 10, gestation = 26 +/- 1 wk, birth weight = 854 +/- 218 g; CTL group, n = 10, gestation = 26 +/- 1 wk, birth weight = 880 +/- 158 g. TEE of the SEP group during the septic period was significantly greater than during the recovery period (96 +/- 25 kcal/kg/d versus 55 +/- 17 kcal/kg/d) and significantly greater than the CTL group during the first study period (96 +/- 25 kcal/kg/d versus 67 +/- 12 kcal/kg/d). TEE in the SEP group during the recovery period was similar to the CTL group. These increases in TEE may contribute to impaired growth and need to be considered when providing nutritional support for extremely premature infants.
No preview · Article · Jun 2007 · Pediatric Research
[Show abstract][Hide abstract] ABSTRACT: To determine whether increased amino acid availability can reduce proteolysis in premature neonates and to assess the capacity of infants born prematurely to acutely increase the irreversible catabolism of the essential amino acids leucine (via oxidation) and phenylalanine (via hydroxylation to form tyrosine), leucine and phenylalanine kinetics were measured under basal conditions and in response to a graded infusion of intravenous amino acids (1.2 and 2.4 g. kg(-1). day(-1)) in clinically stable premature (approximately 32 wk gestation) infants in the 1st wk of life. In contrast to the dose-dependent suppression of proteolysis seen in healthy full-term neonates, the endogenous rates of appearance of leucine and phenylalanine (reflecting proteolysis) were unchanged in response to amino acids (297 +/- 21, 283 +/- 19, and 284 +/- 31 micromol. kg(-1). h(-1) for leucine and 92 +/- 6, 92 +/- 4, and 84 +/- 7 micromol. kg(-1). h(-1) for phenylalanine). Similar to full-term neonates, leucine oxidation (40 +/- 5, 65 +/- 6, and 99 +/- 7 micromol. kg(-1). h(-1)) and phenylalanine hydroxylation (12 +/- 1, 16 +/- 1, and 20 +/- 2 micromol. kg(-1). h(-1)) increased in a stepwise fashion in response to graded amino acids. This capacity to increase phenylalanine hydroxylation may be crucial to meet tyrosine needs when exogenous supply is limited. Finally, to determine whether amino acids stimulate glucose production in premature neonates, glucose rate of appearance was measured during each study period. In response to amino acid infusion, rates of endogenous glucose production were unchanged (and near zero).
No preview · Article · Oct 2001 · AJP Endocrinology and Metabolism
[Show abstract][Hide abstract] ABSTRACT: Infants with cyanotic congenital heart disease (CCHD) have previously been shown to have similar resting energy expenditures (REEs) and elevated total energy expenditures (TEEs) compared with age-matched healthy infants. The purpose of this investigation was to re-examine the REE and TEE of the same individuals at 5 years of age, after surgical repair of the heart defect was done, to determine whether metabolic differences persist.
Seven children were studied approximately 2.6 years after they underwent surgical repair of CCHD along with 10 age-matched healthy children. Indirect calorimetry was used to determine REE, and the doubly labeled water method was used to determine TEE and body composition.
Results were compared with single-factor repeated measures analysis of variance. No significant differences were found between groups in weight or body composition. No significant differences were found between groups in REE, TEE, or the energy expended in physical activity.
We conclude that differences in TEE observed during infancy are no longer present in 5-year-old children after they undergo surgical repair of CCHD. Furthermore, the individual components of energy expenditure of children with CCHD after repair are indistinguishable from those of healthy age-matched children.
No preview · Article · Oct 2000 · Journal of Pediatrics
[Show abstract][Hide abstract] ABSTRACT: Disturbances in growth are often a consequence of congenital heart disease during infancy and childhood. The magnitude of the growth disturbance is generally related to the anatomical lesion and is most severe in infants and children with congestive heart failure. Presently, surgical repair in this population is often delayed in order to permit increased weight gain. Surgery is preformed when a patient reaches an ideal weight and age, or failure to thrive precludes further waiting. The available data indicate that caloric intake in these infants and children may be nearly adequate for age, but is inadequate to permit normal growth rates. Energy expenditure appears to be significantly elevated in this population relative to that of age-matched infants and children. Therefore, while caloric intake may be appropriate for age, increased energy expenditure leaves the infant or child with congenital heart disease with little energy available for growth. More information is needed on energy intakes and expenditures of specific patient populations, and especially of patients with congestive heart failure, before accurate predictions of their metabolic needs are possible. This knowledge may allow us to better meet the nutritional needs of these populations and decrease the risk of malnutrition and failure to thrive, in turn decreasing surgical risk for these patients.
No preview · Article · Oct 2000 · Progress in Pediatric Cardiology
[Show abstract][Hide abstract] ABSTRACT: Information about energy requirements of extremely low-birth weight infants is sparse, despite the rapidly improving survival rates of this population. Metabolizable energy intake can be estimated from energy balance studies and the percentage of caloric intake that is actually absorbed by these infants is approximately 87%. Data on energy expenditure in extremely premature infants is limited; however, energy expenditure has been shown to increase with postnatal age. Because both intake and expenditure are affected by multiple factors, there is significant variability in estimates of the energy requirements in extremely low-birth weight infants. At present, no valid recommendations can be made regarding optimal energy requirements for the extremely low-birth weight infant, except that their requirements probably exceed those of stable, growing very low-birth weight infants, currently estimated at 105 to 135 kcal.kg-1d-1.
No preview · Article · Apr 2000 · Clinics in Perinatology
[Show abstract][Hide abstract] ABSTRACT: Dexamethasone is commonly administered to ventilator-dependent preterm infants with chronic lung disease. Infants receiving dexamethasone therapy frequently exhibit decreased rates of weight gain. The purpose of this investigation was to determine whether decreased growth in infants receiving dexamethasone therapy is caused by increased energy expenditure. Twelve infants were studied: 6 received dexamethasone treatment at 2 wk of age and crossed over to receive placebo treatment at 4 wk; the treatment order was reversed in the other 6 infants. The doubly labeled water method was used to determine energy expenditure for a 1-wk period during each treatment phase. The rate of weight gain during dexamethasone treatment was 6.5+/-10.6 and 20.0+/-5.7 g/kg/d during placebo treatment. Energy expenditure was 93.1+/-34.6 kcal/kg/d during dexamethasone treatment and 88.3+/-37.1 kcal/kg/d during placebo treatment. Energy intake was 119.2+/-29.0 kcal/kg/d during dexamethasone treatment and 113.8+/-23.7 kcal/kg/d during placebo treatment. The difference between intake and expenditure, or the energy available for growth, was 26.2+/-36.8 kcal/kg/d during dexamethasone treatment and 25.5+/-37.4 kcal/kg/d during placebo treatment. No significant differences were found in energy expenditure or energy intake between the treatment phases. The reduced growth seen in infants receiving dexamethasone treatment cannot be explained by increased energy expenditure or decreased energy intake, but may be due to differences in the composition of newly accreted tissue.
No preview · Article · Aug 1999 · Pediatric Research
[Show abstract][Hide abstract] ABSTRACT: Infants with cyanotic congenital heart disease (CCHD) often have reduced weight gain compared with infants in control groups. Our purpose was to conduct a longitudinal study of energy intake, resting energy expenditure (REE), and total energy expenditure (TEE) of a group of infants with CCHD. We hypothesized that increased REE and TEE and decreased energy intake in these infants would lead to reduced growth. Ten infants with uncorrected CCHD and 12 infants in a control group were studied at 2 weeks of age and again at 3 months. Indirect calorimetry was used to determine REE; the doubly labeled water method was used to determine TEE and intake. At 2 weeks and 3 months of age, infants with CCHD weighed significantly less than infants in the control group. No significant difference was seen in energy intake or REE between groups during either period. TEE was slightly but not statistically increased in the CCHD group at 2 weeks (72.6 +/- 17.4 vs 59.8 +/- 10.9 kcal/kg/d) and significantly increased at 3 months (93.6 +/- 23.3 vs 72.2 +/- 13.2 kcal/kg/d, P </=.03). We conclude that increased TEE but not increased REE is a primary factor in the reduced growth in infants with CCHD.
No preview · Article · Jan 1999 · Journal of Pediatrics
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to determine the effect of left-to-right shunting on the resting energy expenditure (REE), total energy expenditure (TEE), and energy intake in a group of 3- to 5-month-old infants with moderate to large unrepaired ventricular septal defects (VSDs) compared with age-matched, healthy infants.
Eight infants with VSDs and 10 healthy controls between 3 to 5 months of age participated in the study. Indirect calorimetry was used to measure REE and the doubly-labeled water method was used to measure TEE and energy intake. An echocardiogram and anthropometric measurements were performed on all study participants. Daily urine samples were collected at home for 7 days. Samples were analyzed by isotope ratio mass spectrometry. Data were compared using analysis of variance.
No significant differences were found in REE (VSD, 42.2 +/- 8.7 kcal/kg/d; control, 43.9 +/- 14.1 kcal/kg/d) or energy intake (VSD, 90.8 +/- 19.9 kcal/kg/d; control, 87.1 +/- 11.7 kcal/kg/d) between the groups. The percent total body water was significantly higher in the VSD infants and the percent fat mass was significantly lower. TEE was 40% higher in the VSD group (VSD, 87.6 +/- 10.8 kcal/kg/d; control, 61.9 +/- 10.3 kcal/kg/d). The difference between TEE and REE, reflecting the energy of activity, was 2.5 times greater in the VSD group.
REE and energy intake are virtually identical between the two groups. Despite this, infants with VSDs have substantially higher TEE than age-matched healthy infants. The large difference between TEE and REE in VSD infants suggests a substantially elevated energy cost of physical activity in these infants. These results demonstrate that, although infants with VSDs may match the energy intake of healthy infants, they are unable to meet their increased energy demands, resulting in growth retardation.
[Show abstract][Hide abstract] ABSTRACT: A method was developed for the determination of the specific activities of leucine and phenylalanine in plasma using a flow-through scintillation counter coupled with high-performance liquid chromatography components. Results were compared with those obtained from liquid scintillation counting. Differences in the specific activities of leucine and phenylalanine between the two methods were not statistically significant. We concluded that flow-through radioactivity detection can be used for quantitative amino acid assays. However, the minimum activity that can be detected may be prohibitively low in certain applications.
No preview · Article · Jul 1998 · Journal of chromatography. B, Biomedical sciences and applications
[Show abstract][Hide abstract] ABSTRACT: To determine the effect of parenteral nutrition on the balance and catabolism of leucine (by oxidation) and phenylalanine (by hydroxylation) and to assess any acute changes in proteolysis and/or protein synthesis, leucine and phenylalanine kinetics were measured by stable isotope tracer infusions in nine 32-wk gestation premature infants under both basal conditions and in response to an i.v. infusion of glucose, lipid, and amino acids. Leucine and phenylalanine balance both changed from negative to positive during parenteral nutrition. However, leucine and phenylalanine catabolism were differently affected by parenteral nutrition; the rate of leucine oxidation increased 2-fold, whereas the rate of phenylalanine hydroxylation was unchanged from basal values. Phenylalanine utilization for protein synthesis and leucine utilization for protein synthesis (based on both plasma leucine and alpha-ketoisocaproic acid enrichments) increased significantly during parenteral nutrition. The endogenous rates of release of leucine (based on plasma leucine enrichment) and phenylalanine (both reflecting proteolysis) were significantly reduced during parenteral nutrition. The endogenous rate of release of leucine (based on alpha-ketoisocaproic acid enrichment) was slightly but not significantly lower during parenteral nutrition. The substantial increase in leucine oxidation without changes in phenylalanine hydroxylation suggests a possible limitation in the phenylalanine/tyrosine supply during parenteral nutrition. In addition, these results suggest that premature infants respond to parenteral nutrition with acute increases in whole body protein synthesis as well as a probable reduction in proteolysis.
No preview · Article · May 1997 · Pediatric Research
[Show abstract][Hide abstract] ABSTRACT: To determine how increased amino acid availability alters rates of whole body proteolysis and the irreversible catabolism of the essential amino acids leucine and phenylalanine throughout the neonatal period, leucine and phenylalanine kinetics were measured under basal conditions and in response to intravenous amino acids in two separate groups of healthy, full-term newborns (at 3 days and 3 wk of age). The endogenous rates of appearance of leucine and phenylalanine (reflecting proteolysis) were suppressed equally in both groups and in a dose-dependent fashion (by approximately 10% with 1.2 g x kg(-1) x day(-1) and by approximately 20% with 2.4 g x kg(-1) x day(-1)) in response to intravenous amino acid delivery. Insulin concentrations remained unchanged from basal values during amino acid administration. The irreversible catabolism of leucine and phenylalanine increased in a stepwise fashion in response to intravenous amino acids; again, no differences were observed between the two groups. This study clearly demonstrates that the capacity to acutely increase rates of leucine oxidation and phenylalanine hydroxylation is fully present early in the neonatal period in normal newborns. Furthermore, these data suggest that amino acid availability is a primary regulator of proteolysis in normal newborns throughout the neonatal period.
No preview · Article · May 1997 · The American journal of physiology
[Show abstract][Hide abstract] ABSTRACT: To determine whether the route of nutrient delivery affects whole-body protein kinetics and fuel utilization, eight premature newborns were studied during both a 4-h period of enteral intake and a 4-h period of parenteral nutrition. The kinetics of the essential amino acid leucine were measured using a constant tracer infusion of 1-13C-leucine, and fuel utilization and energy expenditure were assessed by respiratory calorimetry. All leucine kinetic parameters were similar during enteral or parenteral nutrition (in mean +/- SD mumol/kg/h, flux = 233 +/- 51 enteral versus 258 +/- 42 parenteral, leucine from protein breakdown = 177 +/- 50 enteral versus 200 +/- 41 parenteral, leucine oxidation = 57 +/- 26 enteral versus 63 +/- 20 parenteral, and leucine used for protein synthesis = 176 +/- 63 enteral versus 196 +/- 50 parenteral). In addition, overall rates of energy expenditure (approximately 52 kcal/kg/d) and pattern of fuel utilization (approximately 70% carbohydrate, 13% fat, 17% protein) were unaltered by the route of feeding. Thus, as reflected by leucine kinetics, overall rates of protein turnover, synthesis, oxidation, and breakdown as well as energy expenditure and fuel utilization are similar when nutrition is provided to premature newborns by either the enteral or parenteral route. These results suggest that short-term provision of parenteral nutrition may be able to substitute appropriately for enteral intake, at least with regard to the utilization of one essential amino acid and the overall pattern of fuel utilization.
Full-text · Article · Nov 1994 · Pediatric Research