Elevated systolic blood pressure in preterm very-low-birth-weight infants ≤3 years of life

Follow-up of a randomized trial optimizing neonatal nutrition in preterm very low birthweight infants: growth, serum adipokines, renal function and blood pressure

OBJECTIVE

The primary objectives were to compare body mass index (BMI) Z-score (Z), systolic blood pressure (SBP), serum leptin:adiponectin (L:A) ratio and estimated glomerular filtration rate (eGFR) at ~3 years adjusted age between two arms of a randomized controlled trial (RCT) comparing two modes of human milk fortification for very low-birthweight infants in the neonatal intensive care unit.

STUDY DESIGN

Follow-up of RCT at 33-48 months.

RESULTS

Follow-up data are available in 82/120 infants. Infants in the experimental arm have anthropometric data consistent with central obesity and higher serum L:A ratio (sensitivity analysis adjusting for sex and using all available data), but have similar eGFR and SBP at follow-up compared with controls. Serum L:A ratio is strongly correlated with anthropometric measurements suggesting central obesity.

CONCLUSIONS

Infants in the experimental arm have central obesity and higher serum L:A ratio compared with controls. Notably, serum L:A ratio is strongly correlated with weight gain.

TRIAL REGISTRATION

This randomized controlled trial was registered at ClinicalTrials.gov NCT02372136.

Neonatal Leptin Levels Predict the Early Childhood Developmental Assessment Scores of Preterm Infants

Preterm infants have low circulating levels of leptin, a key trophic hormone that influences growth and development. While the clinical importance of prematurity-associated leptin deficiency is undefined, recent preclinical and clinical investigations have shown that targeted enteral leptin supplementation can normalize neonatal leptin levels. We tested the hypothesis that, independent of growth velocity, prematurity-related neonatal leptin deficiency predicts adverse cardiovascular and neurodevelopmental outcomes. In a planned 2-year longitudinal follow-up of 83 preterm infants born at 22 to 32 weeks' gestation, we obtained blood pressures from 58 children and the Ages & Stages Questionnaire (ASQ-3) for 66 children. Based on univariate analysis, blood pressures correlated with gestational age at birth (R = 0.30, p < 0.05) and weight gain since discharge (R = 0.34, p < 0.01). ASQ-3 scores were significantly higher in female than male children. Utilizing best subset regression with Mallows' C_p as the criterion for model selection, higher systolic blood pressure was predicted by rapid postnatal weight gain, later gestation at delivery and male sex (C_p = 3.0, R = 0.48). Lower ASQ-3 was predicted by lower leptin levels at 35 weeks postmenstrual age, earlier gestation at delivery and male sex (C_p = 2.9, R = 0.45). Children that had leptin levels above 1500 pg/mL at 35 weeks postmenstrual age had the highest ASQ-3 scores at 2 years. In conclusion, independent of growth velocity, higher leptin levels at 35 weeks' gestation are associated with better developmental assessment scores in early childhood. While longer-term follow-up of a larger cohort is needed, these findings support investigations that have suggested that targeted neonatal leptin supplementation could improve the neurodevelopmental outcomes of preterm infants.

Persistent high blood pressure and renal dysfunction in preterm infants during childhood

BACKGROUND

Infants born very preterm (≤32 weeks gestational age, GA) and very-low birth weight (≤1500 g; PT-VLBW) demonstrate high systolic blood pressure (SBP), renal dysfunction, and obesity at 6 months-3 years and in early adulthood. Their parallel measurement and progression during childhood is unclear.

METHODS

We reenrolled 62/120 patients originally seen at 1-3 years at 10-13 years and remeasured anthropometric indices, SBP, and serum creatinine (Cr) and cystatin C (cysC) to determine estimated glomerular filtration rate (eGFR). We selected Term-matched Controls at 10-13 years from the 2015-2016 NHANES database at a ratio of 2 Controls:1 Case (124:62).

RESULTS

Reenrolled patients were predominantly Hispanic, birth weight 1073 ± 251 g, and GA at birth 28 ± 2 weeks. At 10-13 years, 45% were classified overweight/obese, 48% had SBP ≥ 90th centile (77% considered hypertensive), and 34% had low eGFR (<90 mL min^-1 [1.73 m²]^-1). Notably, 57% of reenrolled PT-VLBW Cases had low eGFR_cysC at both 1-3 and 10-13 years, P < 0.03. Compared to Controls, Cases had four times the adjusted odds for having an elevated SBP and low eGFR_Cr despite similar proportions with overweight/obesity among Cases and Controls.

CONCLUSIONS

PT-VLBW infants seen at 1-3 years exhibit obesity, elevated SBP, and low eGFR in infancy and 10-13 years. Although the small sample size may limit conclusions, pediatricians should consider serial evaluations of PT-VLBW throughout childhood.

IMPACT

The association between preterm birth and elevated blood pressure, renal dysfunction, and obesity in young adults begins as early as 1 year and persists at 10-13 years of age. This is the first study reporting serial measurements of blood pressure, renal function, and obesity from infancy to preadolescence in children born very preterm. Fifty-seven percent of preterm 1-3 year olds have persistent low estimated glomerular filtration rate associated with hypertension at 10-13 years. Clinicians should consider serial evaluations of blood pressure, renal function, and obesity throughout infancy and childhood in all preterm births.

Perinatal Origins of Adult Disease and Opportunities for Health Promotion: A Narrative Review

The “developmental origins of health and disease” (DOHaD) hypothesis refers to the influence of early developmental exposures and fetal growth on the risk of chronic diseases in later periods. During fetal and early postnatal life, cell differentiation and tissue formation are influenced by several factors. The interaction between genes and environment in prenatal and early postnatal periods appears to be critical for the onset of multiple diseases in adulthood. Important factors influencing this interaction include genetic predisposition, regulation of gene expression, and changes in microbiota. Premature birth and intrauterine growth restriction (IUGR) are other important factors considered by the DOHaD hypothesis. Preterm birth is associated with impaired or arrested structural or functional development of key organs/systems, making preterm infants vulnerable to cardiovascular, respiratory, and chronic renal diseases during adulthood. Growth restriction, defined as impaired fetal growth compared to expected biological potential in utero, is an additional negative factor increasing the risk of subsequent diseases. Environmental factors implicated in the developmental programming of diseases include exposure to pollution, stress, drugs, toxic agents, nutrition, and exercise. The DOHaD may explain numerous conditions, including cardiovascular, metabolic, respiratory, neuropsychiatric, and renal diseases. Potential antenatal and postnatal preventive measures, interventions, and future directions are discussed.

Cortisol and Cortisone in Early Childhood in Very-Low-Birthweight Infants and Term-Born Infants

INTRODUCTION

Besides programming of the hypothalamic-pituitary-adrenal (HPA) axis, changes in the activity of 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) could contribute to the later metabolic and cardiovascular consequences of preterm birth.

OBJECTIVE

We compared serum cortisol, cortisone, and cortisol/cortisone ratio in early childhood in very-low-birthweight (VLBW) infants and term appropriate for gestational age (AGA) born infants.

METHODS

We included 41 VLBW infants, participating in the randomized controlled Neonatal Insulin Replacement Therapy in Europe trial, and 64 term AGA-born infants. Cortisol and cortisone were measured in blood samples taken at 6 months and 2 years corrected age (VLBW children) and at 3 months and 1 and 2 years (term children). At 2 years of (corrected) age (HDL) cholesterol, triglycerides, glucose, and insulin were also measured.

RESULTS

During the first 2 years of life, cortisol/cortisone ratio is higher in VLBW children compared to term children. In the total group of children, cortisol/cortisone ratio is positively related to triglycerides at 2 years of (corrected) age. In VLBW children, over the first 2 years of life both cortisol and cortisone are higher in the early-insulin group compared to the standard care group.

CONCLUSIONS

In VLBW infants, lower 11β-HSD2 activity probably contributes to the long-term metabolic and cardiovascular risks. In VLBW infants, early insulin treatment could affect programming of the HPA axis, resulting in higher cortisol and cortisone levels during early childhood.

Quality improvement project designed to reduce disproportionate growth in extremely low gestational age neonates: cognitive neurodevelopmental outcome at 18-41 months

OBJECTIVE

To assess if the adjusted odds of low composite cognitive Bayley-III scores changed after implementing a single-institution quality improvement (QI) project designed to decrease discharge Z-scores for weight, body mass index (BMI), and weight-for-length, but not length or fronto-occipital circumference (FOC) in infants 23-28 weeks gestational age (GA).

METHODS

Compare Bayley-III outcomes at ≥18 months corrected age (postnatal age adjusted for prematurity) in infants tested before (Epoch-1) and after (Epoch-2) QI implementation.

RESULTS

Bayley testing was available in 134/156 infants (86%) in Epoch-1 and 139/175 (79%) in Epoch-2. There was no change in frequency of low (<85) cognitive score (p = 0.5) or in median cognitive scores (80 in Epoch-1 vs. 85 Epoch-2, p = 0.35). The adjusted odds of low cognitive scores was not different between Epochs.

CONCLUSION

No change in cognitive outcome at ≥18 months corrected age was observed after implementing a QI project designed to reduce discharge weight-for-length disproportion in very preterm infants.

Adrenal Steroid Metabolism and Blood Pressure in 5- to 7-Year-Old Children Born Preterm as Compared to Peers Born at Term

Background: Previous studies indicated preterm birth to be a risk factor for hypertension in adolescence and adulthood. However, studies in children investigating the underlying mechanisms are scarce. Objective: We hypothesized children born preterm to have higher excretion of cortisol and/or androgen metabolites per day concomitantly with higher blood pressure as compared to peers born at term. We thus aimed to compare urinary steroid profiles and blood pressure between 5- to 7-year-old children born preterm and peers born at term. Furthermore, aldosterone precursor excretion per day was compared between both groups. Methods: Blood pressure was measured in 236 children (preterms n = 116; gestational age 29.8 ± 2.6 (30; 24-33) weeks [mean ± standard deviation (median; range)]) using an automatic oscillometric device. Urinary steroid profiles were determined in 24-h urine samples (preterms n = 109; terms n = 113) using gas chromatographic-mass spectrometric analysis. To assess excretion of cortisol and androgen metabolites per day, major cortisol and androgen metabolites were summed, respectively. To assess aldosterone excretion per day tetrahydrocorticosterone, 5α-tetrahydrocorticosterone, and tetrahydro-11-deydrocorticosterone were summed. Results: Multiple regression analyses showed prematurity to be associated with systolic but not with diastolic blood pressure. When adjusted for potential confounders (prematurity, gender, age at day of examination, being born small for gestational age, breastfeeding, accelerated weight gain during infancy, family history of cardiovascular disease, parental hypertension, and body mass index) prematurity was shown to be associated with an increase in systolic blood pressure by 2.87 mmHg (95% confidence interval 0.48-5.27; p = 0.02). Cortisol, androgen metabolite, and aldosterone precursor excretion per day were not higher in individuals born preterm. In contrast to our hypothesis, multiple regression analysis showed prematurity to independently decrease cortisol and aldosterone precursor excretion per day (p < 0.001 and 0.04, respectively). Conclusion: This study provides further evidence for systolic blood pressure to be higher after preterm birth as early as at the age of 5 to 7 years. However, this seems not to be explained by elevated excretion of cortisol and/or androgen metabolites.

Paternal DNA Methylation May Be Associated With Gestational Age at Birth

Background:

How epigenetic modifications of DNA are associated with gestational age at birth is not fully understood. We investigated potential effects of differential paternal DNA methylation (DNAm) on offspring gestational age at birth by conducting an epigenome-wide search for cytosine-phosphate-guanine (CpG) sites.

Methods:

Study participants in this study consist of male cohort members or partners of the F1-generation of the Isle of Wight Birth Cohort (IoWBC). DNAm levels in peripheral blood from F1-fathers (n = 92) collected around pregnancy of their spouses were analyzed using the Illumina 450K array. A 5-step statistical analysis was performed. First, a training-testing screening approach was applied to select CpG sites that are potentially associated with gestational age at birth. Second, functional enrichment analysis was employed to identify biological processes. Third, by centralizing on biologically informative genes, Cox proportional hazards models were used to assess the hazard ratios of individual paternal CpGs on gestational age adjusting for confounders. Fourth, to assess the validity of our results, we compared our CpG-gestational age correlations within a Born into Life Study in Sweden (n = 15). Finally, we investigated the correlation between the detected CpGs and differential gene expression in F2 cord blood in the IoWBC.

Results:

Analysis of DNAm of fathers collected around their partner’s pregnancy identified 216 CpG sites significantly associated with gestational age at birth. Functional enrichment pathways analyses of the annotated genes revealed 2 biological pathways significantly related to cell-cell membrane adhesion molecules. Differential methylation of 9 cell membrane adhesion pathway-related CpGs were significantly associated with gestational age at birth after adjustment for confounders. The replication sample showed correlation coefficients of 2 pathway-related CpGs with gestational age at birth within 95% confidence intervals of correlation coefficients in IoWBC. Finally, CpG sites of protocadherin (PCDH) gene clusters were associated with gene expression of PCDH in F2 cord blood.

Conclusions:

Our findings suggest that differential paternal DNAm may affect gestational age at birth through cell-cell membrane adhesion molecules. The results are novel but require future replication in a larger cohort.

Association of age of initiation and type of complementary foods with body mass index and weight-for-length at 12 months of age in preterm infants

OBJECTIVE

To assess whether in very preterm infants (1) body mass index (BMI) Z-score and weight-for-length (WtFL) Z-score at 1 year of age and (2) head growth from discharge to 1 year are associated with breastfeeding at discharge and the age of onset and type of complementary foods.

STUDY DESIGN

Observational cohort study.

RESULTS

Infants started on only ready-made complementary (RMC) feedings at ≤26 weeks adjusted age had the highest adjusted BMI Z-score and WtFL Z-score at 1 year of age. Adjusted change in fronto-occipital circumference was highest in infants either discharged on breastmilk or receiving home-made complementary food with/without RMC (HMM) at ≤26 weeks adjusted age.

CONCLUSIONS

Infants started on RMC ≤26 weeks adjusted age had the highest BMI Z-score and WtFL Z-score at 1 year. Head growth from discharge to 1 year was highest in infants either discharged on breastmilk or receiving HMM at ≤26 weeks adjusted age.

Can maternal treatment with metformin during gestation and lactation cause metabolic and cardiovascular disorders in rat offspring?

Objective: The aim was to evaluate if maternal treatment with metformin (MET) during pregnancy and lactation could be safe for metabolic and cardiovascular parameters of adult male and female offspring.Materials and methods: Wistar female rats were treated with MET (293 mg/kg/d) or tap water, by gavage during gestation (METG or CTRG) or gestation and lactation (METGL or CTRGL).Results: At 75 days of life, male and female MET offspring presented similar blood pressure when compared with their CTR. The heart rate of female METGL was higher than in the CTRGL. The insulin sensitivity, basal glycaemia, body weight, Lee index of obesity, plasmatic concentration of triglycerides, total cholesterol and fat acid of male and female MET were similar to CTR groups. Lower fat pad deposition was observed in female METG and METGL.Conclusion: MET exposure during gestational and lactation does not program cardiovascular and metabolic alterations in adult offspring life.

Neonatal oxygen saturations and blood pressure at school-age in children born extremely preterm: a cohort study

OBJECTIVE

To explore the relationship between neonatal oxygen saturation and BP at age 6-7 years in a cohort of infants born extremely preterm.

STUDY DESIGN

Infants <28 weeks gestation were assigned to a higher or lower oxygen saturation target. Oximeter data were monitored throughout the neonatal period. A subset of survivors was seen at age 6. BP was measured and compared by group assignment, achieved saturations, and time spent in hypoxemia (saturations <80%).

RESULTS

There was no difference in systolic or diastolic BP between assigned groups. Median achieved weekly oxygen saturation was not associated with BP. Longer duration of hypoxemia during the first week of age was associated with higher systolic BP.

CONCLUSIONS

Neither target nor actual median oxygen saturations in this study was associated with BP at school age. Increased duration of hypoxemia in the first postnatal week was associated with higher systolic BP at 6-7 years of age.

Optimizing individual nutrition in preterm very low birth weight infants: double-blinded randomized controlled trial

OBJECTIVE

In preterm neonates fed human milk, fortification may be adjusted by (1) optimization, based on growth rate and serum nutrient analyses, or (2) individualization, based on serial milk nutrient analyses. The primary aim was to determine whether individualized plus optimized nutrition (experimental) improves velocity of weight gain and linear growth from birth to endpoint (36 weeks postmenstrual age or discharge) when compared with optimized nutrition alone (controls).

STUDY DESIGN

Double-blinded parallel group randomized trial in 120 neonates <29 weeks gestational age (GA) or <35 weeks and small for GA (birth weight < 10th centile).

RESULT

Weight-gain velocity (13.1 ± 2.1, n = 57 controls, vs. 13.0 ± 2.6 g kg^-1 day^-1, n = 59 experimental, P = 0.87), linear growth (0.9 ± 0.2, n = 55, vs. 0.9 ± 0.2 cm week^-1, n = 52, P = 0.90) and frequency of weight/length disproportion (2% vs. 2%, P = 0.98) were similar in both groups.

CONCLUSIONS

Individualized plus optimized nutrition does not improve weight gain, linear growth, or weight/length disproportion at endpoint versus optimized nutrition alone.

Adjustable feedings plus accurate serial length measurements decrease discharge weight-length disproportion in very preterm infants: quality improvement project

BACKGROUND

Preterm very-low-birth-weight (≤1500 g) infants exhibit disproportionate weight-for-length growth in the Neonatal Intensive Care Unit.

LOCAL PROBLEM

High frequency of body mass index (BMI) > 90th centile at discharge and 1-year postnatal age associated with elevated blood pressure and serum leptin in infancy and adolescence.

METHODS

Single-institution quality improvement project in appropriately grown infants born at 23^0/7-28^6/7 weeks gestational age and discharged home.

INTERVENTION

Adjustable feeding protocol based on valid serial length measurements (board or caliper).

RESULTS

The average monthly percentage of weight-for-length disproportion at discharge decreased from 13% in Epoch 1 to 0% in Epoch 2 (P < 0.05). Although the average Z-score for BMI at discharge was lower in Epoch 2 versus Epoch 1 (P < 0.01), this was absent by 1 year follow-up (P = 0.91).

CONCLUSIONS

Adjustable feedings plus use of accurate serial length measurements decreases weight-for-length disproportion at hospital discharge but not at 1 year.

Risk of hypertension following perinatal adversity: IUGR and prematurity

Consistent with the paradigm shifting observations of David Barker and colleagues that revealed a powerful relationship between decreased weight through 2 years of age and adult disease, intrauterine growth restriction (IUGR) and preterm birth are independent risk factors for the development of subsequent hypertension. Animal models have been indispensable in defining the mechanisms responsible for these associations and the potential targets for therapeutic intervention. Among the modifiable risk factors, micronutrient deficiency, physical immobility, exaggerated stress hormone exposure and deficient trophic hormone production are leading candidates for targeted therapies. With the strong inverse relationship seen between gestational age at delivery and the risk of hypertension in adulthood trumping all other major cardiovascular risk factors, improvements in neonatal care are required. Unfortunately, therapeutic breakthroughs have not kept pace with rapidly improving perinatal survival, and groundbreaking bench-to-bedside studies are urgently needed to mitigate and ultimately prevent the tsunami of prematurity-related adult cardiovascular disease that may be on the horizon. This review highlights our current understanding of the developmental origins of hypertension and draws attention to the importance of increasing the availability of lactation consultants, nutritionists, pharmacists and physical therapists as critical allies in the battle that IUGR or premature infants are waging not just for survival but also for their future cardiometabolic health.

Extreme Preterm Infant Rates of Overweight and Obesity at School Age in the SUPPORT Neuroimaging and Neurodevelopmental Outcomes Cohort

OBJECTIVE

To identify rates of overweight (body mass index [BMI] ≥85th percentile) and obesity (BMI ≥95th percentile) at 6-7 years of age and associated risk factors among extremely preterm infants born at <28 weeks of gestation.

STUDY DESIGN

Anthropometrics, blood pressure, and active and sedentary activity levels were prospectively assessed. Three groups were compared, those with a BMI ≥85th percentile (overweight or obese for age, height, and sex) and ≥95th percentile (obese) vs <85th percentile. Multiple regression analyses estimated the relative risks of BMI ≥85th percentile and ≥95th percentile associated with perinatal and early childhood factors.

RESULTS

Of 388 children, 22% had a BMI of ≥85th percentile and 10% were obese. Children with obesity and overweight compared with normal weight children had higher body fat (subscapular skinfold and triceps skinfold >85th percentile), central fat (waist circumference >90th percentile), spent more time in sedentary activity (20.5 vs 18.2 vs 16.7 hours/week), and had either systolic and/or diastolic hypertension (24% vs 26% vs 14%), respectively. Postdischarge weight gain velocities from 36 weeks postmenstrual age to 18 months, and 18 months to 6-7 years were independently associated with a BMI of ≥85th percentile, whereas weight gain velocity from 18 months to 6-7 years was associated with obesity.

CONCLUSIONS

One in 5 former extremely preterm infants is overweight or obese and has central obesity at early school age. Postdischarge weight gain velocities were associated with overweight and obesity. These findings suggest the obesity epidemic is spreading to the most extremely preterm infants.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00063063 and NCT0000.

Kidneys in 5-year-old preterm-born children: a longitudinal cohort monitoring of renal function

BackgroundBeing aware of the impact of low birth weight on late-onset hypertension, our aim was to describe systolic blood pressure (sBP) and renal function in 3-5-year-old preterm-born children and to determine which perinatal factors or childhood factors were associated with an altered renal function at 5 years in these children.MethodsThis was a prospective longitudinal cohort study of children born at 27-31 weeks of gestation and included at birth and examined at 3, 4, and 5 years of age. The primary outcome was renal function at 5 years: BP, estimated glomerular filtration rate, and albuminuria.ResultsOne hundred and sixty five children were examined, of whom 93 (56.4%) were male. Gestational age was 29.2±1.4 weeks and birth weight was 1,217±331 g. Overall, 25% children had sBP ≥90th percentile at age 3 and 4 years and 11% at 5 years. In multivariate analysis, sBP ≥90th percentile at 5 years was associated with the use of antenatal steroids (OR=0.19(0.05;0.65)). There was a significant association between protein intake on day 28 and sBP at 5 years (β=2.1±1.0, P=0.03). Glomerular filtration rate at 5 years was significantly decreased in case of hyaline membrane disease or necrotizing enterocolitis. High urine albumin was not predictable from one year to another.ConclusionIn preterm-born children, sBP was often high and neonatal protein intake was associated with increased blood pressure during childhood.

Association among prematurity (<30 weeks' gestational age), blood pressure, urinary albumin, calcium, and phosphate in early childhood

BACKGROUND

There is a paucity of data on blood pressures (BP), urinary albumin, and mineral excretion in early childhood in contemporary cohorts of extremely low gestational age (GA) neonates. Our aim was to compare BPs and the urinary excretion of albumin, calcium, and phosphate in preterm and term-born cohorts in early childhood.

METHODS

This was a prospective observational study conducted at a single center, involving children <5 years age, born preterm (GA <30 weeks) or at term (≥37 weeks' GA). Urinary albumin (mg/L), calcium and phosphate levels indexed to creatinine (mg/dL), and BP were measured.

RESULTS

The median (IQR) follow-up age of our cohort (n = 106) was 30 (16-48) months. Preterm-born children (n = 55) had a significantly lower mean GA and birth weight and higher mean systolic, diastolic, and mean BPs, compared with term (n = 51) controls. A significantly higher proportion of preterm-born children weighed <10th centile and had systolic BP >95th centile at follow-up. Albumin and calcium excretion did not differ between the groups; median urine-phosphate creatinine ratios were higher in the preterm group. On logistic regression, lower GA and younger age at follow-up were significantly associated with an increased risk of systolic and diastolic BP above the 95th centile; male gender was associated with decreased risk of diastolic hypertension.

CONCLUSIONS

Even in early childhood, children born preterm had significantly elevated BP, compared with their term-born counterparts. Closer monitoring of BPs in this population may be warranted.

Preterm birth and ventilation decrease surface density of glomerular capillaries in lambs, regardless of postnatal respiratory support mode

BACKGROUND

Prematurity is often complicated by respiratory support, including invasive mechanical ventilation (IMV) and noninvasive support (NIS). Compared with IMV, NIS reduces injury to the lung and brain. Prematurity may also disrupt glomerular architecture. Whether NIS differentially affects glomerular architecture is incompletely understood. We hypothesized that IMV would lead to greater disruption of glomerular architecture than NIS.

METHODS

This is a secondary analysis of kidneys from moderately preterm lambs delivered at ~131 d gestation (term ~150 d) that had antenatal steroid exposure and surfactant treatment before resuscitation by IMV. At ~3 h of age, half of the lambs were switched to NIS. Support was for 3 d or 21 d. Structural indices of glomerular architecture were quantified.

RESULTS

The number of glomerular generations was unaffected by moderate preterm birth and respiratory support, either IMV or NIS. At 3 d and 21 d of IMV or NIS, glomerular capillary surface density was not different. Glomerular capillary surface density was significantly lower in the inner and outer cortex compared with unventilated gestation age-matched or postnatal age-matched reference lambs.

CONCLUSION

Moderate preterm birth and invasive or noninvasive respiratory support decreases glomerular capillarization in the lamb kidney. This adverse effect on glomerular development may contribute to increased risk for adult-onset hypertension and renal dysfunction.

Racial Disparities in Blood Pressure Trajectories of Preterm Children: The Role of Family and Neighborhood Socioeconomic Status

Racial disparities in cardiovascular disease mortality in the United States remain substantial. However, the childhood roots of these disparities are not well understood. In the current study, we examined racial differences in blood pressure trajectories across early childhood in a sample of African-American and European-American low-birth-weight preterm infants. Family and neighborhood socioeconomic status (SES), measured at baseline, were also examined as explanations for subsequent group disparities. Analyses focused on 407 African-American and 264 European-American children who participated in the Infant Health and Development Program, a US longitudinal study of preterm children born in 1985. Blood pressure was assessed on 6 occasions between the ages of 24 and 78 months, in 1987-1992. Across this age range, the average rate of change in both systolic and diastolic blood pressure was greater among African-American children than among European-American children. Neighborhood SES explained 29% and 24% of the racial difference in the average rate of change in systolic and diastolic blood pressure, respectively, whereas family SES did not account for group differences. The findings show that racial differences in blood pressure among preterm children emerge in early childhood and that neighborhood SES accounts for a portion of racial disparities.

Biomarkers of adiposity are elevated in preterm very-low-birth-weight infants at 1, 2, and 3 y of age

BACKGROUND

Preterm, very-low-birth-weight (PT-VLBW) neonates are at-risk for metabolic syndrome later in life. At 1-3 y, they exhibit excessive weight-for-length z-scores (Wt-L_Z) and elevated systolic blood pressures (SBP). Serum adipokines are biomarkers of adiposity, but expression in PT-VLBW infants is unclear. We examined the correlation between serum adipokine levels, anthropometric measures and SBP in PT-VLBW neonates at follow-up.

METHODS

This was a cross-sectional cohort study of PT-VLBW infants at 1, 2, and 3 y of age (40/cohort). We measured SBP, abdominal circumference (AC) and anthropometrics; calculated age/gender-specific z-scores for Wt, L, Wt-L and subscapular skin fold (SS_Z), and measured serum adipokines.

RESULTS

Serum leptin was unaffected by chronologic age and gender, but was positively correlated with weight, Wt-L_Z, AC, and SS_Z at 1 and 3 y (P < 0.01). Female infants at 1 and 3 y had a more significant relationship than males between serum leptin and SS_Z (P < 0.001, R = 0.75 and P < 0.001, R = 0.70, respectively). Adiponectin levels were 16-20% lower at 3 vs. 1-2 y (P = 0.02, ANOVA) and negatively correlated with SBP.

CONCLUSION

Although serum leptin was unrelated to advancing age, gender, and SBP in PT-VLBW infants, levels correlated with measures of adiposity at 1 and 3 y, females > males, suggesting leptin resistance may occur in early infancy.

Modeling the impact of growth and leptin deficits on the neuronal regulation of blood pressure

The risk of hypertension is increased by intrauterine growth restriction (IUGR) and preterm birth. In the search for modifiable etiologies for this life-threatening cardiovascular morbidity, a number of pathways have been investigated, including excessive glucocorticoid exposure, nutritional deficiency and aberration in sex hormone levels. As a neurotrophic hormone that is intimately involved in the cardiovascular regulation and whose levels are influenced by glucocorticoids, nutritional status and sex hormones, leptin has emerged as a putative etiologic and thus a therapeutic agent. As a product of maternal and late fetal adipocytes and the placenta, circulating leptin typically surges late in gestation and declines after delivery until the infant consumes sufficient leptin-containing breast milk or accrues sufficient leptin-secreting adipose tissue to reestablish the circulating levels. The leptin deficiency seen in IUGR infants is a multifactorial manifestation of placental insufficiency, exaggerated glucocorticoid exposure and fetal adipose deficit. The preterm infant suffers from the same cascade of events, including separation from the placenta, antenatal steroid exposure and persistently underdeveloped adipose depots. Preterm infants remain leptin deficient beyond term gestation, rendering them susceptible to neurodevelopmental impairment and subsequent cardiovascular dysregulation. This pathologic pathway is efficiently modeled by placing neonatal mice into atypically large litters, thereby recapitulating the perinatal growth restriction-adult hypertension phenotype. In this model, neonatal leptin supplementation restores the physiologic leptin surge, attenuates the leptin-triggered sympathetic activation in adulthood and prevents leptin- or stress-evoked hypertension. Further pathway interrogation and clinical translation are needed to fully test the therapeutic potential of perinatal leptin supplementation.

Schoolchildren born VLBW or VLGA show height-related changes in body composition and muscle function but no evidence of metabolic syndrome risk factors. Results from the NEOLONG study

BACKGROUND

Children born small for gestational age (SGA) are at risk for the metabolic syndrome (MetS) as adults. We examined whether indicators of MetS could be identified in pre-pubertal children born very preterm.

METHODS

Parameters associated with MetS were studied in 141 pre-pubertal schoolchildren with either very low birth weight (VLBW) or GA <32 weeks (SGA: n=43).

RESULTS

At 8.3±0.8 years, 36 children (SGA: n=15) were classified short. There were no differences between the SGA and appropriate for age (AGA) groups; nor were dissimilarities observed between short children and those with normal height for parameters such as body mass index (BMI), serum levels of hormones, HDL cholesterol, triglycerides, glucose, insulin, HOMA-IR, body composition, resting energy expenditure, grip strength and jump force.

CONCLUSIONS

Neither SGA at birth nor short stature at follow-up (irrespective of size at birth), could be associated with parameters that indicate an increased risk for the MetS during childhood.

Salivary and serum cortisol and relation to blood pressure in infancy and early childhood in very-low-birth-weight infants

BACKGROUND

Programming of the hypothalamic-pituitary-adrenal (HPA) axis possibly explains the relation between intrauterine growth restriction (IUGR) and/or preterm birth and elevated blood pressure in later life. Very-low-birth-weight infants (birth weight <1,500 g) have high prevalence of raised blood pressure, already in early childhood. We investigated cortisol levels, relation to blood pressure and reliability of salivary cortisol in infancy and early childhood in very-low-birth-weight infants.

METHODS

We included 41 children, participating in the randomized controlled Neonatal Insulin Replacement Therapy in Europe (NIRTURE) trial. Serum and salivary samples for cortisol measurement (immunoassay) were taken simultaneously at 6 mo and separately at 2 y corrected age. Blood pressure was measured at 2 y corrected age.

RESULTS

Serum cortisol was significantly correlated to systolic and diastolic blood pressure in boys and in the early-insulin treated group. At 2 y corrected age serum cortisol was significantly higher in the early-insulin group compared to the standard care group. At 6 mo corrected age salivary cortisol was significantly correlated to serum cortisol.

CONCLUSION

In very-low-birth-weight boys, the positive correlation between cortisol and blood pressure is present at 2 y corrected age. Early insulin therapy could affect programming of the HPA axis. Salivary cortisol mirrors serum levels at 6 mo corrected age.

Blood pressure measurement at two years in offspring of women randomized to a trial of metformin for GDM: follow up data from the MiG trial

Background

Offspring born following maternal gestational diabetes are at risk of excessive childhood weight gain and Type 2 diabetes in childhood, which in turn is associated with an increased rate of hypertension.

We aimed to determine the systolic and diastolic blood pressure at two years of age in a cohort of children exposed to gestational diabetes mellitus using data from the MiG trial of metformin use in gestational diabetes. The secondary aim was to analyze these data by randomization of treatment to insulin or metformin.

Methods

The offspring of women who had gestational diabetes and had been assigned to either open treatment with metformin (with supplemental insulin if required) or insulin in the MiG trial were followed up at 2 years of age. Oscillometric measurement of BP in the right arm was performed by a researcher using an appropriately sized cuff.

Results

A total of 489 measurement blood pressure measurements were obtained in 170 of the 222 children who were seen at a median (range) age of 29 (22–38) months corrected gestational age. At the time of assessment the mean (SD) weight and height was 13.8(2) kg and 90 (4.2) cm respectively. For the whole group the mean (SD) systolic pressure was 90.9 (9.9) mmHg and mean (SD) diastolic pressure was 55.7 (8.1) mmHg. No difference was found between the metformin and insulin treatment arms. In a regression model, height and weight were only two factors associated with the levels of systolic blood pressure. For each additional kg the systolic blood pressure increased by 1.0 mmHg. For each additional cm of height the systolic blood pressure increased by 0.42 mmHg.

Conclusions

Blood pressure data was obtained at approximately two years of age in a substantial cohort of children whose mothers received treatment for GDM. These novel data compare favorably with published norms.

Clinical Trials Registry

This study was registered under the Australian New Zealand Clinical Trials Registry (ACTRN12605000311651).

Renal function and systolic blood pressure in very-low-birth-weight infants 1-3 years of age

BACKGROUND

Preterm very-low-birth-weight (PT-VLBW) infants are at risk of an elevated systolic blood pressure (SBP) in infancy and adulthood; however, the pathogenesis remains unclear. Altered renal development or function may be associated with increased SBP, but their contribution in PT-VLBW is unknown.

METHODS

We determined renal function and its relationship to SBP in three groups of PT-VLBW at 1, 2, and 3 years of age, using serum cystatin-C to calculate the estimated glomerular filtration rate (eGFR).

RESULTS

Cystatin-C levels decreased from 0.84 ± 0.2 (SD) within the 1-year group to 0.70 ± 0.1 mg/l (±SD; P < 0.001) at 3 years and were unrelated to gender, fetal growth, and neonatal indomethacin exposure. eGFR rose from 121 ± 59 in the 1-year group to 138 ± 21 ml/min · 1.73 m(2) (P < 0.001) at 3 years. At 1 year, cystatin-C levels decreased with increasing SBP (P < 0.007), and infants with SBP ≥ 90 th% had lower cystatin-C and higher eGFR (P < 0.05). At 3 years, infants with lower birth weight (P < 0.03) and gestational age (P = 0.06) had reduced eGFR.

CONCLUSIONS

Preterm very-low-birth-weight infants demonstrate increasing renal function with advancing age. An elevated SBP and eGFR at 1 year suggests dysfunctional renal autoregulation and hyperfiltration, which may alter subsequent renal function and contribute to the lower eGFR seen at 3 years in infants with the lowest birth weight and gestational age.

Developmental programming of hypertension and kidney disease

A growing body of evidence supports the concept that changes in the intrauterine milieu during "sensitive" periods of embryonic development or in infant diet after birth affect the developing individual, resulting in general health alterations later in life. This phenomenon is referred to as "developmental programming" or "developmental origins of health and disease." The risk of developing late-onset diseases such as hypertension, chronic kidney disease (CKD), obesity or type 2 diabetes is increased in infants born prematurely at <37 weeks of gestation or in low birth weight (LBW) infants weighing <2,500 g at birth. Both genetic and environmental events contribute to the programming of subsequent risks of CKD and hypertension in premature or LBW individuals. A number of observations suggest that susceptibility to subsequent CKD and hypertension in premature or LBW infants is mediated, at least in part, by reduced nephron endowment. The major factors influencing in utero environment that are associated with a low final nephron number include uteroplacental insufficiency, maternal low-protein diet, hyperglycemia, vitamin A deficiency, exposure to or interruption of endogenous glucocorticoids, and ethanol exposure. This paper discusses the effect of premature birth, LBW, intrauterine milieu, and infant feeding on the development of hypertension and renal disease in later life as well as examines the role of the kidney in developmental programming of hypertension and CKD.

Developmental origins of health and adult disease: what should neonatologists/paediatricians be considering about the long-term health of their patients?

The developmental origins of health and disease hypothesis is now strongly supported by both animal and human evidence, and as a consequence, obstetricians, neonatologists and paediatricians need to consider the impact that the in utero and early post-natal environment can have on later renal, cardiovascular and metabolic health. Four common clinical scenarios were provided along with animal and human evidence identifying long-term health implications. Suggestions as to how we should translate this growing body of evidence into practice are provided.

Management of blood pressure in children

PURPOSE OF REVIEW

This review summarizes recent insights into the epidemiology of primary hypertension in children, with emphasis on the most important risk factors for the development of hypertension, and also updates current options for treating primary hypertension in children.

RECENT FINDINGS

There is growing evidence that the prevalence of hypertension has increased over the past decade and that the epidemic of obesity has played a key role in the increase of blood pressure (BP) in the USA and abroad. Recent studies have shown that in addition to obesity, environmental factors such as second-hand smoking and sedentary lifestyle are important in development of hypertension even in preschool age children. Studies also have confirmed the effect of vegetables and fruits on lowering BP. Recent clinical trials of valsartan and olmesartan have provided efficacy and safety information for use in children.

SUMMARY

The increased prevalence of hypertension in children in recent years emphasizes the need for a more aggressive approach to screen and diagnose elevated BP even in early childhood. Early initiation of treatment is important to decrease the risk of cardiovascular morbidity in adulthood.

Increased albuminuria in 4-year-old preterm-born children with normal height

OBJECTIVE

To determine risk factors for high blood pressure (BP), increased markers of glomerulosclerosis, and tubular dysfunction in 4-year-old preterm-born children.

STUDY DESIGN

The study group was a longitudinal cohort of 119 children with BP, albuminuria, and β2 microglobulin measurements obtained during the neonatal period and at age 4 years.

RESULTS

Systolic BP was >95(th) percentile in 15 (12.6%) of the children at age 4 years and lower in those born small for gestational age compared with those born appropriate for gestational age. Preterm-born 4-year-olds with height <-1 SD had lower systolic and diastolic BP, and 14.4% of the 4-year-olds had albuminuria. Albuminuria was less prevalent in the 4-year-olds with height <-1 SD than in those with height ≥-1 SD (6.8% vs 19.3%; P=.04). Mean albuminuria level was 1.0±0.7 mg/mmol in 4-year-olds with height <-1 SD and 1.4±1.3 mg/mmol in those with height ≥-1 SD. In multivariate analysis, albuminuria level was increased by 0.4±0.2 mg/mmol in preterm-born children with normal height at age 4, and by 0.5±0.2 mg/mmol in females, after adjustment for gestational age, sex, neonatal morbidity, and intrauterine growth restriction. These results were unchanged after adjustment for body mass index.

CONCLUSION

Normal height at age 4 years may be associated with an increased risk for glomerulosclerosis in preterm-born children.