Insights into the pathophysiology of catch-up compared with non-catch-up growth in children born small for gestational age: an integrated analysis of metabolic and transcriptomic data

Birth weight and prepubertal growth trajectory had a combined effect on pubertal initiation in girls

AIM

Most studies of prepubertal weight and puberty have not used continuous or long follow-up periods. We explored the effect that birth weight and growth trajectories from 0-9 years of age had on starting puberty.

METHODS

Data were obtained from 1510 children in Tianjin, China, who were born in 2013 and selected by cluster random sampling. Information on pubertal status was collected by parent-reported questionnaires and up to 14 anthropometric measurements were obtained from physical examinations. A group-based trajectory model was applied to fit the growth trajectories. Cox regression and log-binomial regression were used for association analyses.

RESULTS

After exclusions, we studied 1164 children (50.9% girls) up to a mean age of 9.6 years. Girls with a low birth weight or low-stable growth trajectories were less likely to have started puberty, while those with macrosomia or high-stable growth trajectories had a higher risk of having started puberty. Combined analyses showed that the risk of pubertal initiation for girls with a normal birth weight and low-stable trajectories was 0.76. It was 1.42 for those with macrosomia and high-stable trajectories. Similar results were not found in the boys.

CONCLUSION

It is important that pubertal initiation studies investigate growth over the life course.

Associations between birthweight and preterm birth and the ages at menarche and menopause

BACKGROUND

Women who reach menarche and menopause at earlier ages have been shown to be at increased risk for numerous conditions including cardiovascular disease, cancer, depression, and obesity; however, risk factors for earlier ages of menarche and menopause are not fully understood. Therefore, we aimed to perform a retrospective investigation of the associations between a personal birthweight and/or being born preterm and the age of and menarche and menopause and related events in the Women's Health Initiative, a large, racially and ethnically diverse cohort of postmenopausal women.

METHODS

At study entry, women reported their birthweight by category (< 6 lbs., 6-7 lbs. 15 oz, 8-9 lbs. 15 oz, or ≥ 10 lbs.) and preterm birth status (4 or more weeks premature). Ages at events related to menarche and menopause were also self-reported. Linear regression and logistic regression models were used to estimate unadjusted and adjusted effect estimates (β) and odds ratios (OR), respectively (n ≤ 86,857). Individuals born preterm were excluded from all birthweight analyses.

RESULTS

After adjustments, individuals born weighing < 6lbs. were more likely to reach natural menopause at an earlier age (adjusted β=-0.361, SE = 0.09, P = < 0.001) and have a shorter reproductive window (adjusted β = -0.287, SE = 0.10, p < 0.004) compared to individuals weighing 6-7 lbs. 15 oz. Individuals born preterm were also more likely to reach natural menopause at an earlier age (adjusted β=-0.506, SE = 0.16, P = 0.001) and have a shorter reproductive window (adjusted β = -0.418, SE = 0.17, p < 0.006).

CONCLUSIONS

These findings raise concerns that, as more preterm and low birthweight individuals survive to adulthood, the prevalence of earlier-onset menarche and menopause may increase. Clinical counseling and interventions aimed at reducing the incidence of preterm and low birthweight births, as well as intensification of lifestyle modifications to reduce CVD risk among women with these early-life risk factors, should be prioritized.

Unraveling the Mfn2-Warburg effect nexus: a therapeutic strategy to combat pulmonary arterial hypertension arising from catch-up growth after IUGR

BACKGROUND

The interplay between intrauterine and early postnatal environments has been associated with an increased risk of cardiovascular diseases in adulthood, including pulmonary arterial hypertension (PAH). While emerging evidence highlights the crucial role of mitochondrial pathology in PAH, the specific mechanisms driving fetal-originated PAH remain elusive.

METHODS AND RESULTS

To elucidate the role of mitochondrial dynamics in the pathogenesis of fetal-originated PAH, we established a rat model of postnatal catch-up growth following intrauterine growth restriction (IUGR) to induce pulmonary arterial hypertension (PAH). RNA-seq analysis of pulmonary artery samples from the rats revealed dysregulated mitochondrial metabolic genes and pathways associated with increased pulmonary arterial pressure and pulmonary arterial remodeling in the RC group (postnatal catch-up growth following IUGR). In vitro experiments using pulmonary arterial smooth muscle cells (PASMCs) from the RC group demonstrated elevated proliferation, migration, and impaired mitochondrial functions. Notably, reduced expression of Mitofusion 2 (Mfn2), a mitochondrial outer membrane protein involved in mitochondrial fusion, was observed in the RC group. Reconstitution of Mfn2 resulted in enhanced mitochondrial fusion and improved mitochondrial functions in PASMCs of RC group, effectively reversing the Warburg effect. Importantly, Mfn2 reconstitution alleviated the PAH phenotype in the RC group rats.

CONCLUSIONS

Imbalanced mitochondrial dynamics, characterized by reduced Mfn2 expression, plays a critical role in the development of fetal-originated PAH following postnatal catch-up growth after IUGR. Mfn2 emerges as a promising therapeutic strategy for managing IUGR-catch-up growth induced PAH.

A Scoping Review: Urinary Markers of Metabolic Maturation in Preterm Infants and Future Interventions to Improve Growth

Background: Growth failure in infants born preterm is a significant issue, increasing the risk of poorer neurodevelopmental outcomes and metabolic syndrome later in life. During the first 1000 days of life biological systems mature rapidly involving developmental programming, cellular senescence, and metabolic maturation, regulating normal growth and development. However, little is known about metabolic maturation in infants born preterm and the relationship with growth. Objective: To examine the available evidence on urinary markers of metabolic maturation and their relationship with growth in infants born preterm. Eligibility criteria: Studies including in this scoping review using qualitative or quantitative methods to describe urinary markers of metabolic maturation and the relationship with growth in infants born preterm. Results: After a screening process 15 titles were included in this review, from 1998-2021 drawing from China (n = 1), Italy (n = 3), Germany (n = 3), Greece (n = 1), Japan (n = 2), Norway (n = 1), Portugal (n = 1), Spain (n = 2) and USA (n = 1). The included studies examined urinary metabolites in 1131 infants. A content analysis identified 4 overarching themes relating to; (i) metabolic maturation relative to gestational age, (ii) metabolic signature and changes in urinary metabolites over time, (iii) nutrition and (iv) growth. Conclusion: The results of this scoping review suggest there are considerable gaps in our knowledge relating to factors associated with metabolic instability, what constitutes normal maturation of preterm infants, and how the development of reference phenome age z scores for metabolites of interest could improve nutritional and growth outcomes.

Gene expression signatures predict response to therapy with growth hormone

Recombinant human growth hormone (r-hGH) is used as a therapeutic agent for disorders of growth including growth hormone deficiency (GHD) and Turner syndrome (TS). Treatment is costly and current methods to model response are inexact. GHD (n = 71) and TS patients (n = 43) were recruited to study response to r-hGH over 5 years. Analysis was performed using 1219 genetic markers and baseline (pre-treatment) blood transcriptome. Random forest was used to determine predictive value of transcriptomic data associated with growth response. No genetic marker passed the stringency criteria for prediction. However, we identified an identical set of genes in both GHD and TS whose expression could be used to classify therapeutic response to r-hGH with a high accuracy (AUC > 0.9). Combining transcriptomic markers with clinical phenotype was shown to significantly reduce predictive error. This work could be translated into a single genomic test linked to a prediction algorithm to improve clinical management. Trial registration numbers: NCT00256126 and NCT00699855.

Effects of rapid growth on fasting insulin and insulin resistance: a system review and meta-analysis

Infants with congenital deficiency have high risk of glucose metabolism disorder, and often experience rapid growth in early childhood. However, the role of rapid growth on glucose metabolism is controversial. We conducted a systematic review and meta-analysis to examine the association of rapid growth with fasting insulin and homeostasis model assessment of insulin resistance (HOMA-IR). We searched EMBASE and Medline for English articles, and CNKI and WANFANG database for Chinese articles. Studies measuring the associations between rapid growth and insulin or HOMA-IR were included. Relevant information was extracted independently by two reviewers. Random effects model was adopted for combined and stratified analyses. At last, twenty-two relevant studies for insulin and 20 for HOMA-IR were identified. Rapid growth was associated with high insulin (weighted mean differences [WMD] 5.544, 95% confidence interval [CI] [1.436, 9.653], P = 0.008) and high HOMA-IR (WMD 0.194, 95% CI [0.098, 0.290], P < 0.001). This elevated association was statistically significant in rapid growth subjects that were >6 years old, full-term, and from developed countries. However, rapid growth among low birth weight subjects did not lead to high insulin and HOMA-IR, but decreased HOMA-IR among preterm children (WMD -0.305, 95% CI [-0.607, -0.004], P = 0.047). Follow-up age was positively correlated with HOMA-IR (r = 0.095, P < 0.001). This meta-analysis suggested that rapid growth would result in high insulin and HOMA-IR, especially for full-term infants. However, rapid growth is relatively harmless for subjects who are <6 years old, low birth weight or SGA, and is even protective for preterm subjects.

Growth patterns over 2 years after birth according to birth weight and length percentiles in children born preterm

PURPOSE

To analyze growth patterns over 2 years after birth according to preterm infant birth weight and length percentiles.

METHODS

Anthropometric measurements of 82 preterm infants were retrospectively reviewed. Preterm infants with birth weight or length below the 10th percentile were classified as small for gestational age (SGA) (n=19) and those between the 10th and 89th percentile as appropriate for gestational age (AGA) (n=63). The association between the length standard deviation score (SDS) at 2 years of corrected age and clinical factors were analyzed.

RESULTS

The length SDS of the SGA group was significantly increased at 6 months (-1.30±1.71) and 24 months (-0.97±1.06) of corrected age. The length SDS was lower in the SGA group than those in the AGA group at 6 months (-1.30±1.71 vs. -0.25±1.15, P=0.004), 18 months (-0.97±1.39 vs. -0.03±1.29, P=0.015), and 24 months (-0.97±1.06 vs. -0.29±1.12, P=0.022,). The percentage of children with a length SDS of <-2 (growth failure) at 24 months was 15.8% in the SGA group and 4.8% in the AGA group (P=0.108). Multiple linear regression analysis demonstrated that length at 24 months of corrected age was negatively correlated with birth length below the 10th percentile (coefficient β=-0.91, P=0.001) and duration of stay in the neonatal intensive care unit (NICU) (coefficient β=-0.01, P=0.001).

CONCLUSION

Despite the fact that catch-up growth occurs during the early period of infancy in a large portion of preterm SGA infants, a significant portion of these infants show growth failure at 24 months of age. Growth over 2 years after birth is affected by birth length and duration of stay in the NICU in preterm children.

Children Born Small for Gestational Age: Differential Diagnosis, Molecular Genetic Evaluation, and Implications

Children born small for gestational age (SGA), defined as a birth weight and/or length below -2 SD score (SDS), comprise a heterogeneous group. The causes of SGA are multifactorial and include maternal lifestyle and obstetric factors, placental dysfunction, and numerous fetal (epi)genetic abnormalities. Short-term consequences of SGA include increased risks of hypothermia, polycythemia, and hypoglycemia. Although most SGA infants show catch-up growth by 2 years of age, ∼10% remain short. Short children born SGA are amenable to GH treatment, which increases their adult height by on average 1.25 SD. Add-on treatment with a gonadotropin-releasing hormone agonist may be considered in early pubertal children with an expected adult height below -2.5 SDS. A small birth size increases the risk of later neurodevelopmental problems and cardiometabolic diseases. GH treatment does not pose an additional risk.

Height at three months can indicate overweight at two years in catch-up growth of small for gestational age infants

This study aimed to find an indicator at three months to predict overweight and short stature at two years in small for gestational age (SGA) infants. A total of 468 SGA infants and 4642 appropriate for gestational age (AGA) infants were included. Weight and height were measured at birth, three months and two years. Logistic regression and receiver operating characteristic (ROC) curves were performed for the catch-up growth. As compared to AGA infants, the weight of SGA infants was lower and the length/height was shorter at birth, three months, and two years. The weight of the catch-up group was significantly greater at birth and two years. The length/height of the catch-up group was greater at three months and two years. Trajectories of weight standard deviation score (SDS) and height SDS showed that the overweight group (BMI over the 85th percentile) had a shorter length/height SDS but a higher rate of the change in weight SDS during catch-up growth. The multivariate logistic regression indicated that that height at three months was an independent factor for prediction of catch-up growth at two years. The area under curve (AUC) was 0.801 with the 95% confidence interval (CI) from 0.726 to 0.876. Therefore, height at three months can predict overweight at two years.

A Translational Model of Incomplete Catch-Up Growth: Early-Life Hypoxia and the Effect of Physical Activity

Advances in therapies have led to prolonged survival from many previously lethal health threats in children, notably among prematurely born babies and those with congenital heart disease. Evidence for catch‐up growth is common in these children, but in many cases the adult phenotype is never achieved. A translational animal model is required in which specific tissues can be studied over a reasonable time interval. We investigated the impact of postnatal hypoxia (HY) (12%O₂ (HY12) or 10% O₂ (HY10)) on growth in rats relative to animals raised in room air. Subgroups had access to running wheels following the HY period. Growth was fully compensated in adult HY12 rats but not HY10 rats. The results of this study indicate that neonatal hypoxia can be a useful model for the elucidation of mechanisms that mediate successful catch‐up growth following neonatal insults and identify the critical factors that prevent successful catch‐up growth.

Identification of the functional pathways altered by placental cell exposure to high glucose: lessons from the transcript and metabolite interactome

The specific consequences of hyperglycaemia on placental metabolism and function are incompletely understood but likely contribute to poor pregnancy outcomes associated with diabetes mellitus (DM). This study aimed to identify the functional biochemical pathways perturbed by placental exposure to high glucose levels through integrative analysis of the trophoblast transcriptome and metabolome. The human trophoblast cell line, BeWo, was cultured in 5 or 25 mM glucose, as a model of the placenta in DM. Transcriptomic analysis using microarrays, demonstrated 5632 differentially expressed gene transcripts (≥± 1.3 fold change (FC)) following exposure to high glucose. These genes were used to generate interactome models of transcript response using BioGRID (non-inferred network: 2500 nodes (genes) and 10541 protein-protein interactions). Ultra performance-liquid chromatography-mass spectrometry (MS) and gas chromatography-MS analysis of intracellular extracts and culture medium were used to assess the response of metabolite profiles to high glucose concentration. The interactions of altered genes and metabolites were assessed using the MetScape interactome database, resulting in an integrated model of systemic transcriptome (2969 genes) and metabolome (41 metabolites) response within placental cells exposed to high glucose. The functional pathways which demonstrated significant change in response to high glucose included fatty acid β-oxidation, phospholipid metabolism and phosphatidylinositol phosphate signalling.

Birth weight, early life weight gain and age at menarche: a systematic review of longitudinal studies

BACKGROUND AND OBJECTIVE

Adiposity in pre- and postnatal life may influence menarcheal age. Existing evidence is primarily cross-sectional, failing to address temporality, for which the role of adiposity in early life remains unclear. The current study sought to systematically review longitudinal studies evaluating the associations between birth weight and infant/childhood weight status/weight gain in relation to menarcheal age.

METHODS

PubMed, EMBASE, Web of Science, Global Health (Ovid) and CINAHL were systematically searched. Selected studies were limited to English-language articles presenting multi-variable analyses. Seventeen studies reporting risk estimates for birth weight (n = 3), infant/childhood weight gain/weight status (n = 4) or both (n = 10), in relation to menarcheal age were included.

RESULTS

Lower vs. higher birth weight was associated with earlier menarche in nine studies and later menarche in one study, while three studies reported a null association. Greater BMI or weight gain over time and greater childhood weight were significantly associated with earlier menarche in nine of nine and six of seven studies, respectively.

CONCLUSIONS

Studies suggested that lower birth weight and higher body weight and weight gain in infancy and childhood may increase the risk of early menarche. The pre- and postnatal period may thus be an opportune time for weight control interventions to prevent early menarche, and its subsequent consequences.

Developmental programming of somatic growth, behavior and endocannabinoid metabolism by variation of early postnatal nutrition in a cross-fostering mouse model

Background

Nutrient deprivation during early development has been associated with the predisposition to metabolic disorders in adulthood. Considering its interaction with metabolism, appetite and behavior, the endocannabinoid (eCB) system represents a promising target of developmental programming.

Methods

By cross-fostering and variation of litter size, early postnatal nutrition of CB6F1-hybrid mice was controlled during the lactation period (3, 6, or 10 pups/mother). After weaning and redistribution at P21, all pups received standard chow ad libitum. Gene expression analyses (liver, visceral fat, hypothalamus) were performed at P50, eCB concentrations were determined in liver and visceral fat. Locomotor activity and social behavior were analyzed by means of computer-assisted videotracking.

Results

Body growth was permanently altered, with differences for length, weight, body mass index and fat mass persisting beyond P100 (all 3>6>10,p<0.01). This was paralleled by differences in hepatic IGF-I expression (p<0.01). Distinct gene expression patterns for key enzymes of the eCB system were observed in fat (eCB-synthesis: 3>6>10 (DAGLα p<0.05; NAPE-PLD p = 0.05)) and liver (eCB-degradation: 3>6>10 (FAAH p<0.05; MGL p<0.01)). Concentrations of endocannabinoids AEA and 2-AG in liver and visceral fat were largely comparable, except for a borderline significance for higher AEA (liver, p = 0.049) in formerly overfed mice and, vice versa, tendencies (p<0.1) towards lower AEA (fat) and 2-AG (liver) in formerly underfed animals. In the arcuate nucleus, formerly underfed mice tended to express more eCB-receptor transcripts (CB1R p<0.05; CB2R p = 0.08) than their overfed fellows. Open-field social behavior testing revealed significant group differences, with formerly underfed mice turning out to be the most sociable animals (p<0.01). Locomotor activity did not differ.

Conclusion

Our data indicate a developmental plasticity of somatic growth, behavior and parameters of the eCB system, with long-lasting impact of early postnatal nutrition. Developmental programming of the eCB system in metabolically active tissues, as shown here for liver and fat, may play a role in the formation of the adult cardiometabolic risk profile following perinatal malnutrition in humans.

Growth Hormone Deficiency in Prepubertal Children: Predictive Markers of Cardiovascular Disease

BACKGROUND

Cardiovascular (CV) risk factors have been identified in adults with untreated growth hormone deficiency (GHD). Existing evidence suggests that the development of the atheromatous plaque begins early in childhood. Previous reports have shown that GHD children are prone to increased CV risks including impaired cardiac function, dyslipidemia and abnormalities in body composition. Recent studies in epigenetics and metabolomics have defined specific fingerprints that might be associated with an increased risk of CV disease.

AIM

The aim of this review is to point out the most significant biochemical and clinical predictive markers of CV disease in prepubertal children and to evaluate the effect of recombinant human growth hormone therapy on most of these alterations. The novel findings in epigenetics and metabolomics are also reviewed, with a particular focus on translating them into clinical practice.

Metabolites involved in glycolysis and amino acid metabolism are altered in short children born small for gestational age

BACKGROUND

Later life metabolic dysfunction is a well-recognized consequence of being born small for gestational age (SGA). This study has applied metabolomics to identify whether there are changes in these pathways in prepubertal short SGA children and aimed to compare the intracellular and extracellular metabolome in fibroblasts derived from healthy children and SGA children with postnatal growth impairment.

METHODS

Skin fibroblast cell lines were established from eight SGA children (age 1.8-10.3 y) with failure of catch-up growth and from three healthy control children. Confluent cells were incubated in serum-free media and the spent growth medium (metabolic footprint), and intracellular metabolome (metabolic fingerprint) were analyzed by gas-chromatography mass spectrometry.

RESULTS

Nineteen metabolites were significantly altered between SGA and control cell lines. The greatest fold difference (FD) was seen for alanine (fingerprint FD, SGA: control 0.3, P = 0.01 and footprint FD = 0.19, P = 0.01), aspartic acid (fingerprint FD = 5.21, P = 0.01), and cystine (footprint FD = 1.66, P = 0.02). Network analysis of the differentially expressed metabolites predicted inhibition of insulin as well as growth (ERK) signaling in SGA cells.

CONCLUSION

This study indicates that changes in cellular metabolism associated with both growth failure and insulin insensitivity are present in prepubertal short children born SGA.

What Have Metabolomics Approaches Taught Us About Type 2 Diabetes?

Type 2 diabetes (T2D) is increasing worldwide, making identification of biomarkers for detection, staging, and effective prevention strategies an especially critical scientific and medical goal. Fortunately, advances in metabolomics techniques, together with improvements in bioinformatics and mathematical modeling approaches, have provided the scientific community with new tools to describe the T2D metabolome. The metabolomics signatures associated with T2D and obesity include increased levels of lactate, glycolytic intermediates, branched-chain and aromatic amino acids, and long-chain fatty acids. Conversely, tricarboxylic acid cycle intermediates, betaine, and other metabolites decrease. Future studies will be required to fully integrate these and other findings into our understanding of diabetes pathophysiology and to identify biomarkers of disease risk, stage, and responsiveness to specific treatments.

Catch-up growth and catch-up fat in children born small for gestational age

Infants born small for gestational age (SGA) are at increased risk of perinatal morbidity, persistent short stature, and metabolic alterations in later life. Recent studies have focused on the association between birth weight (BW) and later body composition. Some reports suggest that fetal nutrition, as reflected by BW, may have an inverse programing effect on abdominal adiposity later in life. This inverse association between BW and abdominal adiposity in adults may contribute to insulin resistance. Rapid weight gain during infancy in SGA children seemed to be associated with increased fat mass rather than lean mass. Early catch-up growth after SGA birth rather than SGA itself has been noted as a cardiovascular risk factor in later life. Children who are born SGA also have a predisposition to accumulation of fat mass, particularly intra-abdominal fat. It is not yet clear whether this predisposition is due to low BW itself, rapid postnatal catch-up growth, or a combination of both. In this report, we review the published literature on central fat accumulation and metabolic consequences of being SGA, as well as the currently popular research area of SGA, including growth aspects.

Early postnatal alteration of body composition in preterm and small-for-gestational-age infants: implications of catch-up fat

The concept of the developmental origins of health and disease is based on studies by Barker et al. They proposed a hypothesis that undernutrition in utero permanently changes the body's structure, function, and metabolism in ways that lead to atherosclerosis and insulin resistance in later life. In addition, profound effects on the extent of body fatness and insulin sensitivity are demonstrated, if there is a "mismatch" between prenatal and postnatal environments. In previous studies, undernutrition in utero has been evaluated simply by birth weight itself or birth weight for gestational age, and the degree of mismatch has been estimated by postnatal rapid weight gain. Recently, we investigated subcutaneous fat accumulation in small-for-gestational-age infants and found that a rapid catch-up in skinfold thickness developed prior to the body weight catch-up. Furthermore, insulin-like growth factor-I and lipoprotein lipase mass concentrations also demonstrate rapid increase during the neonatal period with fat accumulation. Investigating the precise mechanisms of developmental origins of health and disease including mediating metabolic and hormonal factors may provide a new approach to prevent atherosclerosis and insulin resistance. Better management of undernutrition during gestation and neonatal growth during the early postnatal period is an important theme for future health.