The impact of early nutrition in premature infants on later childhood insulin sensitivity and growth

Placental inflammatory response is associated with poor neonatal growth: preterm birth cohort study

OBJECTIVE

We sought to determine whether placental markers of intrauterine inflammation were associated with poor weight gain among premature infants in the neonatal period.

METHODS

We reviewed 697 preterm births prospectively enrolled as part of an ongoing molecular epidemiological study. Placental markers and serial weight gain were analyzed for premature infants who were hospitalized for >/=21 days (N = 256). Placentas were examined for maternal inflammatory response (MIR), defined as subchorionitis, chorioamnionitis, deciduitis, or free membranitis, and fetal inflammatory response (FIR), defined as inflammation extending to the umbilical cord or chorionic plate. Multivariate linear regression and stratified analyses were performed.

RESULTS

Decreases in weight gain at day 21 were associated with the presence of either MIR or FIR (beta coefficient = -4.63 +/- 1.41; P = .001). The association was stronger with FIR than MIR (P for trend = .0027) and persisted in the remaining hospitalized infants at day 28 (n = 223; beta coefficient = -5.53 +/- 1.85; P = .0028). Mean body weights were similar among the 3 groups by corrected age of 36 weeks or discharge, whichever came first. Associations between placental inflammation and poor growth persisted among infants with prenatal corticosteroid exposure and/or neonatal complications and remained marginally significant in the nonexposed groups. Among infants without intrauterine growth restriction, significant association persisted (n = 186; beta coefficient = -5.68 +/- 1.56; P = .0003).

CONCLUSIONS

Placental inflammation is associated with poor neonatal growth. MIR and FIR may be useful markers for identifying infants at risk for postnatal growth failure.

Altered body composition in preterm infants at hospital discharge

AIM

To test the hypotheses that body size is reduced and body composition altered in preterm infants at hospital discharge.

METHODS

Preterm infants (< or = 34 weeks gestation, < or = 1750 g at birth) were enrolled. Body weight, length and head circumference were converted to standard deviation or z-scores. Body composition was measured using dual emission X-ray absorptiometry. The results were analysed using standard statistics.

RESULTS

One hundred and forty-nine infants (birth weight = 1406 +/- 248 g, gestation = 31 +/- 1.7 weeks) were studied. Postmenstrual age at discharge was 37 +/- 1.2 weeks. Z-scores for head circumference, weight and length differed (-0.1 +/- 0.6 > -1.4 +/- 0.6 > -1.9 +/- 0.6; p < 0.0001). Global fat-free mass was less in study infants than the reference infant at the same weight (2062 < 2252 g; p < 0.0001) or gestation (2062 < 2667 g; p < 0.0001). Global fat mass was greater in study infants than the reference infant at the same weight (307 > 198 g, 13 > 8%) or gestation (307 > 273 g; 13 > 9%; p < 0.0001). Changes in central fat mass closely paralleled those in global fat mass (r(2) = 0.76, p < 0.0001).

CONCLUSION

Reduced linear growth and a reduced fat-free mass suggest that dietary protein needs were not met before discharge. A reduced fat-free mass coupled with an increased global and central fat mass echoes concerns about the development of insulin resistance and metabolic syndrome X in these high-risk infants.

Obesity and preterm birth: additive risks in the progression of kidney disease in children

Preterm birth is associated with decreased nephron mass and obesity that may impact on kidney disease progression in later life. Our objectives were to examine the relative risks of obesity and preterm birth on the progression of kidney disease in children. In a retrospective cohort study, 80 (44 obese and 36 non-obese) patients with proteinuric kidney disease were studied for disease progression and glomerular histomorphometry. Of the obese, 22 had been born at term (Obese-T) and 22 had been preterm (Obese-PT). Seventeen non-obese children with focal glomerular sclerosis, born at term (NO-FSGS), and 19 non-obese preterm (NO-PT) children, served as controls. Insulin resistance as measured by the homeostatic model assessment (HOMA-IR) was elevated in all obese children. Obese-PT patients had increased risk of renal demise during childhood when compared with Obese-T children [hazard ratio 2.4; 95% Confidence interval (95% CI) 1.1 to 7.1; P = 0.04]. In obese children, although proteinuria often exceeded nephrotic range, average levels of serum albumin remained normal. Preterm patients were more likely to have reduced renal mass (odds ratio 4.7; P = 0.006), but obesity was not a factor. Renal histomorphometry showed glomerulomegaly in obese patients, regardless of birth weight. Obesity and preterm birth appear to impose additive risks for progression of kidney disease in childhood.

Obesity-related nephropathy in children

Concurrent with the global obesity epidemic, there is an increasing number of people of all ages developing chronic kidney disease associated with obesity. In adults, the definition of obesity is a BMI greater than 30 kg/m2. Whereas, in children, a BMI greater than the 85th percentile for age is considered overweight and greater than the 95th percentile is classified as obese. Clinical and pathologic characteristics of a distinct nephropathy have emerged independent of that of diabetic or hypertensive glomerulosclerosis. These include a silent presentation in an obese individual with heavy proteinuria, normal serum albumin and the absence of edema. Renal pathologic findings are notable for mesangial matrix expansion, glomerular hypertrophy and reduced density of podocytes with detachment of foot processes from the glomerular basement membrane. These findings are frequently associated with the development of secondary focal segmental glomerulosclerosis. Obesity alone does not appear to be the sole mediator of this nephropathy. It is most likely the ‘second hit’ for individuals who have congenital or acquired reduced nephron mass as well as an inherited genetic vulnerability to the metabolic consequences imposed by cytokines released by adipose tissue. In children, those born of low birthweight, whether small for gestational age and/or preterm, are likely to have reduced nephron mass as well as an increased tendency for early insulin resistance and the development of obesity and the metabolic syndrome. This in turn is perpetuated by the practice of feeding high-calorie fortified formulas to low-birthweight infants. Rapid catch-up growth, early obesity and insulin resistance are major contributors to the emergence of obesity-related glomerulopathy in children and adolescents. Early detection requires recognizing the demographics of high-risk infants and monitoring them for the development of hypertension, elevated glomerular filtration rate, hyperfiltration and proteinuria. After 6 months of age, angiotensin-blocking agents may be used to control blood pressure, glomerular hyperfiltration and proteinuria. If obesity is present, a comprehensive program of weight loss, including diet and exercise, should be the mainstay of treatment. In older children and adolescents, lipid-lowering medications may be indicated. With morbid obesity, bariatric surgery may be an option.

Perinatal maternal fat intake affects metabolism and hippocampal function in the offspring: a potential role for leptin

Both undernutrition and overnutrition of the mother during pregnancy and lactation produce a syndrome of altered energy balance in the offspring and has long-lasting consequences on CNS systems regulating food intake, metabolism, and food reward. Homeostatic circulating factors like insulin, glucocorticoids, and leptin that are generally increased by exposure to high fat/high caloric diets constitute important signals in these processes. They trigger functional activation of specific intracellular cascades mediating cellular sensitivity, survival, and synaptic plasticity. Using a model whereby the late fetal and neonatal rat is exposed to increased high fat (HF) via HF feeding of the mother, we investigated the proximal (neonatal) and distal (adult) consequences on metabolism and hippocampal function in the offspring. Adult offspring of HF-fed mothers displayed several of the physiological and behavioral changes susceptible to leading to metabolic complications. These include elevated circulating concentrations of leptin and corticosterone, increased body weight gain and food intake, modest preference for fat-containing food types, as well as the onset of hypothalamic leptin resistance. In the hippocampus, HF-fed offspring or neonates treated with leptin show similar increases in neurogenesis and survival of newborn neurons. We identified some of the direct effects of leptin to increase synaptic proteins, N-methyl-d-aspartate (NMDA), and glucocorticoid receptors, and to reduce long-term potentiation (LTP) prior to weaning. While these studies have documented effects in animal models, concepts can easily be translated to human nutrition in order to help design better perinatal diets and nutritional preventive measures for mothers in a coordinated effort to curb the obesity trend.

Early postnatal weight gain, intellectual performance, and body mass index at 7 years of age in term infants with intrauterine growth restriction

OBJECTIVE

To determine whether the postnatal growth rate of infants with intrauterine growth restriction (IUGR) is associated with later cognitive function and body mass index (BMI).

STUDY DESIGN

Infants with IUGR (<2211 g at > or =37 weeks' gestation) were identified in data from the Collaborative Perinatal Project, excluding those with diagnoses affecting cognition or growth. Wechsler Scale of Children's Intelligence (WISC) scores at age 7 years and data on postnatal growth at 16 weeks were available for 463 infants with IUGR. Linear regression relating postnatal growth and WISC score, adjusting for potential confounders, was performed for these infants. BMI at 7 years also was examined.

RESULTS

Weight gain at 16 postnatal weeks ranged from 1059 to 5119 g in the infants with IUGR, with lower achieved cognitive testing scores apparent at both extremes (ie, an inverted J-shape; P < .001). Infants gaining 1200 and 5000 g scored 15.5 and 2.4 fewer points, respectively, on the full scale compared with infants with score-maximizing growth. In contrast, BMI at 7 years was linearly related to postnatal weight gain (P < .001).

CONCLUSIONS

Growth in the first 4 postnatal months is an independent risk factor for cognitive outcome at age 7 years, with both extremes associated with negative effects.

Early exercise regimen improves insulin sensitivity in the intrauterine growth-restricted adult female rat offspring

We examined the effect of early exercise training (Ex) on glucose kinetics, basal, and insulin-stimulated skeletal muscle (SKM) plasma membrane (PM) GLUT4 in pre- and/or postnatal nutrient-restricted adult rat offspring compared with sedentary (Sed) state. Pregestational control female (Ex CON vs. Sed CON) and offspring exposed to prenatal (Ex IUGR vs. Sed IUGR), postnatal (Ex PNGR vs. Sed PNGR), or pre- and postnatal (Ex IUGR + PNGR vs. Sed IUGR + PNGR) nutrient restriction were studied. The combined effect of exercise and pre/postnatal nutrition in the Ex IUGR demonstrated positive effects on basal and glucose-stimulated plasma insulin response (GSIR) with suppression of endogenous hepatic glucose production (HGP) compared with sedentary state. Ex PNGR was hyperglycemic after glucose challenge with no change in glucose-stimulated insulin production or HGP compared with sedentary state. Ex IUGR + PNGR remained glucose tolerant with unchanged glucose-stimulated insulin production but increased endogenous HGP compared with sedentary state. Basal SKM PM-associated GLUT4 was unchanged by exercise in all four groups. Whereas Ex PNGR and Ex IUGR + PNGR insulin responsiveness was similar to that of Ex CON, Ex IUGR remained nonresponsive to insulin. Early introduction of regular Ex in the pregestational female offspring had a positive effect on hepatic adaptation to GSIR and HGP in IUGR and IUGR + PNGR, with no effect in PNGR. Change in insulin responsiveness of SKM GLUT4 translocation was observed in exercised IUGR + PNGR and PNGR but not in exercised IUGR.

Gestational age and risk factors for cardiovascular disease: evidence from the 1958 British birth cohort followed to mid-life

BACKGROUND

Increases in pre-term births and improved survival rates have led to interest in the association between gestational age and health in adulthood. Associations between gestational age and risk factors for cardiovascular disease have not been fully investigated.

METHODS

Using data from the 1958 British birth cohort (7847 singletons), the associations between gestational age and blood pressure, glycosylated haemoglobin (HbA1c), lipid levels and body mass index (BMI) at age 44-45 years were examined.

RESULTS

After adjustment for sex, birthweight standardized for gestational age and sex and current BMI there was a reduction in systolic blood pressure of 0.53 mmHg (95% CI: 0.32, 0.75) for every 1 week increase in gestational age. There was a non-linear association between gestational age and diastolic blood pressure, with those cohort members born at earlier gestational ages found to have higher diastolic blood pressure than those born at term. These associations remained after adjustments. A 'U'-shaped association was found between gestational age and BMI among women (P = 0.02 for sex x gestational age interaction) which attenuated after adjustment. There was also a weak inverse association between gestational age and total cholesterol specific to women (P = 0.01 for sex x gestational age interaction). No clear associations were found between gestational age and BMI or total cholesterol in men, or between gestational age and HbA1c or other lipid levels in either sex.

CONCLUSIONS

In the 1958 British birth cohort duration of gestation was associated with blood pressure in mid-life. Understanding this association is necessary to inform policy and preventative interventions.

The role of ghrelin and ghrelin analogues in wasting disease

PURPOSE OF REVIEW

The purpose of this review is to summarize recent studies that investigated the role of ghrelin and ghrelin analogs in wasting conditions.

RECENT FINDINGS

Numerous studies have demonstrated potential beneficial effects exerted by ghrelin in a number of diseases associated with wasting. Besides ghrelin's orexigenic effect, anabolic as well as anti-inflammatory activity mediated by ghrelin have been investigated in wasting conditions such as cancer, diabetes mellitus, malabsorptive diseases, chronic obstructive pulmonary disease, anorexia nervosa, renal failure, liver failure, and chronic heart failure. Encouraging results have been obtained from experimental studies and a few clinical trials using subcutaneous administration of ghrelin and ghrelin agonists in cachexia. In-vitro studies have shown ghrelin and des-acyl ghrelin biological activities on proliferation of tumor cells and abnormal tissues.

SUMMARY

The recent studies support the possible positive effects of ghrelin in therapeutic approaches and adjunct treatment of a number of diseases associated with wasting. Utilization of agonists of the ghrelin receptor growth hormone secretagogue-1a is a promising approach for clinical use. Randomized and placebo-controlled studies, including large number of patients are further required.

Circulating adiponectin in preterm infants fed long-chain polyunsaturated fatty acids (LCPUFA)-supplemented formula--a randomized controlled study

Adiponectin has potent insulin-sensitizing effects, improves lipid metabolism, and potentially protects against the development of metabolic syndrome. Thus, increasing adiponectin levels in preterm infants at risk for developing metabolic syndrome may be of special interest. The aim of this study was to examine the effects of dietary long-chain polyunsaturated fatty acids (LCPUFA) on serum adiponectin and lipid concentrations in preterm infants. Adiponectin and lipid levels of 60 healthy preterm infants [gestational age 32.7 (1.9) wk] randomly assigned to be fed either 1) a formula containing LCPUFA [arachidonic and docosahexanoic] (+LCPUFA group) or 2) the same formula without LCPUFA (-LCPUFA/control group), were determined at mean (SD) 33.8 (11.7) d. Adiponectin and HDL-C concentrations were significantly higher in the +LCPUFA group than in controls (p = 0.002 and p = 0.01, respectively); whereas, triglyceride levels were lower (p = 0.06). Adiponectin correlated positively with HDL-C levels and negatively with triglyceride levels in the +LCPUFA group but not in the controls. In conclusion, circulating adiponectin concentrations were higher in preterm infants fed a formula containing LCPUFA than infants fed an LCPUFA-free formula and they correlated with lipidemic profile.

Growth of low birth weight preterm children

Very low birth weight premature (VLBWPT) infants demonstrate growth patterns in the early years of life which differ from those of term and large low birth weight preterm (LBWPT) peers. Optimal post natal growth of VLBWPT children is associated with more positive later health and neurodevelopmental outcomes. The neonatologist engaged in the follow of care of VLBWPT infants after discharge from the Neonatal Intensive Care Unit should monitor over time the velocity of weight, length, head circumference and weight/length ratio utilizing appropriate growth references. VLBW children who demonstrate atypically low weight gain in the early years of life have a higher probability of less than optimal cognitive development over time, while those with excessive weight gain have a greater likelihood of later childhood and adult obesity, cardiovascular disease, and diabetes. Nutritional planning should provide adequate calories for gradual normalization in all growth variables, while attempting to avoid atypically low or excessive weight gain. This nutritional planning should take into account the child's genetic growth potential, small for gestational age (SGA) or at gestational age (AGA), and clinical issues such as the presence of diseases like gastroesophageal (GE) reflux or chronic lung disease. Whatever nutritional approach is used, the neonatologist in follow up should track weight, length, head circumference, and weight/length ratio and adjust the nutrition plan and caloric intake to assure gradual return to normal in all growth variables while avoiding excessive weight gain.

Long-term adverse outcomes of low birth weight, increased somatic growth rates, and alterations of body composition in the premature infant: review of the evidence

In appropriate-for-gestational-age preterm infants, data are reviewed to support that both high and low nutrient intakes, as well as fast or slow rates of growth in the neonatal intensive care unit, have long-term adverse (or even positive) effects on body weight and the metabolic syndrome later in life. Though more studies are needed, it is concluded that it is likely that any such effects will be relatively small compared with other risk factors such as parental weight and various lifestyle factors. At the present time, there is little evidence that negates the goal of maximizing nutritional support for the very low birth weight infant in the neonatal period.

Assessing the impact of preterm nutrition

Growth is the traditional means of assessing the impact of newborn nutrition. We argue that this approach is flawed as the optimum pattern of postnatal growth after extremely preterm birth is unknown and both growth restraint and growth acceleration are associated with beneficial as well as adverse outcomes. Clinical trials examining nutritional regimens should be designed to achieve specific patterns of postnatal growth. Clinical practice should include the systematic capture of neonatal nutritional intake. As the ultimate goals are adult health and wellbeing, long-term follow-up is essential.

Association of the growth hormone receptor d3-variant and catch-up growth of preterm infants with birth weight of less than 1500 grams

BACKGROUND

Preterm infants with very low birth weight frequently exhibit impaired longitudinal growth during the first years of life. Recently, the d3-isoform (genomic deletion of exon 3) of the GH receptor (GHR) has been linked to an increased responsiveness to GH.

OBJECTIVE

Our objective was to test whether the GHRd3 isoform is associated with postnatal catch-up growth in very low birth weight preterm infants.

DESIGN AND PATIENTS

We compared the postnatal growth pattern of 77 otherwise healthy preterm infants (mean gestational age, 28.5 wk; range, 23-35 wk) with a birth weight below 1500 g (mean birth weight, 941 g) to their GHR exon 3 genotype, which was analyzed by multiplex PCR. On examination, mean age of the children was 6.0 yr (range, 4.2-8.0 yr).

RESULTS

Children homozygous or heterozygous for the GHRd3 allele showed a significantly higher rate of postnatal catch-up, compared with those homozygous for the full-length allele.

CONCLUSIONS

Our results define the GHR exon 3 genotype as a predictor for the postnatal growth pattern of very low birth weight preterm infants. Those who carry at least one GHRd3 allele are more likely to catch-up.

Integration of physiological and molecular mechanisms of the developmental origins of adult disease: new concepts and insights

It is now well established that an imbalance or reduction in the maternal diet either through pregnancy and lactation or at defined time points therein can have long-term effects on cardiovascular and metabolic health in the resulting offspring; the exact outcome varying greatly with the period of development or growth targeted. The EARly Nutrition programming – long-term follow up of Efficacy and Safety Trials and integrated epidemiological, genetic, animal, consumer and economic research (EARNEST), or metabolic programming, project aims to determine the primary physiological and molecular mechanisms that cause long-term changes in both cardiovascular function and metabolic homeostasis. Thereafter, it also aims to examine nutritional interventions that could be adopted in order to overcome such complications. The present review summarises some of the more recent findings from a range of nutritional interventions in both small and large animals that are beginning to uncover novel pathways by which long-term health can be determined. These interventions include nutritional manipulations that can increase or decrease blood pressure in the resulting offspring as well as indicating their dissociation from adaptations in the kidney. Particular emphasis will be placed on growth during lactation in conjunction with the extent to which central and peripheral tissue adaptations can act to amplify, or protect, the offspring from later disease when born to nutritionally-manipulated mothers.

Glucose regulation in young adults with very low birth weight

BACKGROUND

The association between small size at birth and impaired glucose regulation later in life is well established in persons born at term. Preterm birth with very low birth weight (<1500 g) is also associated with insulin resistance in childhood. If insulin resistance persists into adulthood, preterm birth with very low birth weight also may be associated with an increased risk of disease in adulthood. We assessed glucose tolerance and insulin sensitivity and measured serum lipid levels and blood pressure in young adults with very low birth weight.

METHODS

We performed a standard 75-g oral glucose-tolerance test, measuring insulin and glucose concentrations at baseline and at 120 minutes in 163 young adults (age range, 18 to 27 years) with very low birth weight and in 169 subjects who had been born at term and were not small for gestational age. The two groups were similar with regard to age, sex, and birth hospital. We measured blood pressure and serum lipid levels, and in 150 very-low-birth-weight subjects and 136 subjects born at term, we also measured body composition by means of dual-energy x-ray absorptiometry.

RESULTS

As compared with the subjects born at term, the very-low-birth-weight subjects had a 6.7% increase in the 2-hour glucose concentration (95% confidence interval [CI], 0.8 to 12.9), a 16.7% increase in the fasting insulin concentration (95% CI, 4.6 to 30.2), a 40.0% increase in the 2-hour insulin concentration (95% CI, 17.5 to 66.8), an 18.9% increase in the insulin-resistance index determined by homeostatic model assessment (95% CI, 5.7 to 33.7), and an increase of 4.8 mm Hg in systolic blood pressure (95% CI, 2.1 to 7.4). Adjustment for the lower lean body mass in the very-low-birth-weight subjects did not attenuate these relationships.

CONCLUSIONS

Young adults with a very low birth weight have higher indexes of insulin resistance and glucose intolerance and higher blood pressure than those born at term.

Could epigenetics play a role in the developmental origins of health and disease?

Following Barker's observations of an association between birth size and later adult diseases, considerable efforts have been made to define the characteristics of low birth weight groups in childhood. In this review, the phenotypic and biochemical characteristics during childhood of three low birth weight groups are summarized: children born following inviter fertilization (IVF), small for gestational age (SGA), or very premature. Each of these groups is likely to have been exposed to an adverse environment at different developmental stages. The triggers and mechanisms leading to programmed changes in growth, development, and metabolism of these groups of children have yet to be identified. Epigenetics has been proposed as a potential mechanism for these programmed changes through environmentally induced changes in gene expression. Data from animal models in which environmental, particularly nutritional, manipulation leads to changes in DNA methylation are presented. The relevance of these animal studies to IVF, SGA, and very premature children are discussed as are potential candidate genes that may have undergone epigenetic modification to alter growth and metabolism.

Post-discharge nutrition: what does the evidence support?

Although there are no official recommendations for specific nutrient intakes in premature infants after hospital discharge, it is agreed that the goal should be to achieve the body composition and rate of growth of that of a normal fetus of the same postmenstrual age during the entire first year of life. A general recommendation to use the special formulas designed for preterm infants after hospital discharge in place of the formulas for term infants cannot be made from the available evidence at this time. Infants fed human milk after discharge are of the greatest concern as human milk does not in theory meet the requirements for growth in these infants. Such infants should remain on supplemental vitamins and Fe while breastfeeding, and growth as well as serum levels of phosphorus and alkaline phosphatase should be carefully monitored. The increased risk of preterm infants for obesity and the metabolic syndrome secondary to the metabolic/nutritional events early in life (programming) is likely to be small compared with the contribution of other risk factors, such as parental size, weight as an adolescent, and various lifestyle factors such as physical activity.