Year Of Postnatal Life Research Articles

Association between maternal c-reactive protein levels in pregnancy and growth trajectories of head circumference during the first year of postnatal life – a secondary data analysis of a case-control study on autism

Association between maternal c-reactive protein levels in pregnancy and growth trajectories of head circumference during the first year of postnatal life – a secondary data analysis of a case-control study on autism

A Curated Compendium of Transcriptomic Data for the Exploration of Neocortical Development.

Vast quantities of multi-omic data have been produced to characterize the development and diversity of cell types in the cerebral cortex of humans and other mammals. To more fully harness the collective discovery potential of these data, we have assembled gene-level transcriptomic data from 188 published studies of neocortical development, including the transcriptomes of ~30 million single-cells, extensive spatial transcriptomic experiments and RNA sequencing of sorted cells and bulk tissues: nemoanalytics.org/landing/neocortex. Applying joint matrix decomposition (SJD) to mouse, macaque and human data in this collection, we defined transcriptome dynamics that are conserved across mammalian neurogenesis and which elucidate the evolution of outer, or basal, radial glial cells. Decomposition of adult human neocortical data identified layer-specific signatures in mature neurons and, in combination with transfer learning methods in NeMO Analytics, enabled the charting of their early developmental emergence and protracted maturation across years of postnatal life. Interrogation of data from cerebral organoids demonstrated that while broad molecular elements of in vivo development are recapitulated in vitro, many layer-specific transcriptomic programs in neuronal maturation are absent. We invite computational biologists and cell biologists without coding expertise to use NeMO Analytics in their research and to fuel it with emerging data (carlocolantuoni.org).

Learning phonetic categories in infancy: The role of word-context information

Identifying the type of mechanisms at the core of phonetic categorization remains a central subject of research in infant language learning. Amongst different theories, one is that infants compute distributional information of phonemes based on their surrounding sounds (i.e., word context) such that phonemes that appear in different word contexts are more likely to be discriminated and categorized separately than phonemes that appear in similar word contexts. Following the procedure of Feldman et al. (2013a), we investigated the role of contextual information in the acquisition of phonetic categories in 8-month-old infants, using a non-native vowel contrast (English /ɒ/-/ʌ/). In Experiment 1, we established lack of discrimination of the non-native contrast without prior exposure to it. In Experiment 2, we manipulated the type of exposure prior to testing: half of the infants were exposed to minimal pair carriers (words that differ by one phoneme only; e.g., lituh and litoh), and the other half of the infants were exposed to non-minimal pair carriers (words formed by different phonemes; e.g., lituh and nutoh). All infants were tested for discrimination of the contrast (tuh vs. toh) presented as alternating (e.g., tuh-toh-tuh-toh) and non-alternating trials (e.g., tuh-tuh-tuh), as in Experiment 1. Infants in both conditions looked on average longer at alternating rather than non-alternating trials, suggesting that they discriminated the /ɒ/-/ʌ/ contrast after a brief exposure to the vowels embedded into words. Crucially, discrimination occurred regardless of whether words were minimal pair carriers or non-minimal pair carriers. A cross-experiment comparison revealed that infants showed different patterns of looking times based on whether they were exposed to the contrast before testing (Experiment 2) or not (Experiment 1). Our study shows that any type of word context helps infants to re-establish discrimination of non-native contrasts once sensitivity has been lost. These findings aid to better understand how the speech input modulates learning mechanisms during the establishment of phonetic categories in the first year of postnatal life.

Use of Simple Skull Radiographs in Orbital Correlations in Nigeria

Introduction: Anthropometric measurements have been carried out in many studies to segregate people into races, ethnicity and various biological traits in the past. Such studies include cephalometry being deployed because of its significance in forensic and clinical evaluations of individuals. The objective of this study is to determine the correlation between the shape types of the orbit with different age groups and their prevalence using simple skull X-rays.
 Materials and Methods: Plain X-rays of the skull with posteroanterior exposures were obtained for a retrospective period of 5-year period from 2004 to 2009. The selected radiographs were those based on clear recognition of their orbital margins assessed by 2 experienced Radiologist who determined the shapes of the orbits as being oval, circular or quadrangular. Out of total of five hundred (500) plain X-rays of the skull obtained, only 255 satisfied the inclusion criteria.
 The data was analyzed statistically using INSTAT software to compare the mean values in relation to age distribution of the subjects with the Student’s T-Test. Chi-Square (with Yates correction) was used for the comparison of proportions.
 Results: In the first 30 years of postnatal life, the oval shape orbit had been found to be more predominant with values of 22(64.7%), 17(30.9%), and 27(38.0%) respectively. As from the age of 30 to 70 years, the circular type had values of 16(34.0%), 8(33.3%), and 8(61.5%) respectively in each of the decades. Between the age of 60 to 70 years, the oval and circular types had equal prevalences.
 Conclusions: In addition to the known oval and quadrangular (triangular) types of orbital shape, this study revealed a 3rd type of orbit which we described as circular in shaped. The oval type of orbit is found to be more common from birth to age of 30 years but from but from 40 to 70 years the circular type predominates.

Human deprivation amblyopia: treatment insights from animal models.

Amblyopia is a common visual impairment that develops during the early years of postnatal life. It emerges as a sequela to eye misalignment, an imbalanced refractive state, or obstruction to form vision. All of these conditions prevent normal vision and derail the typical development of neural connections within the visual system. Among the subtypes of amblyopia, the most debilitating and recalcitrant to treatment is deprivation amblyopia. Nevertheless, human studies focused on advancing the standard of care for amblyopia have largely avoided recruitment of patients with this rare but severe impairment subtype. In this review, we delineate characteristics of deprivation amblyopia and underscore the critical need for new and more effective therapy. Animal models offer a unique opportunity to address this unmet need by enabling the development of unconventional and potent amblyopia therapies that cannot be pioneered in humans. Insights derived from studies using animal models are discussed as potential therapeutic innovations for the remediation of deprivation amblyopia. Retinal inactivation is highlighted as an emerging therapy that exhibits efficacy against the effects of monocular deprivation at ages when conventional therapy is ineffective, and recovery occurs without apparent detriment to the treated eye.

Chemosensory continuity from prenatal to postnatal life in humans: A systematic review and meta-analysis.

Throughout pregnancy, fetuses are exposed to a range of chemosensory inputs influencing their postnatal behaviors. Such prenatal exposure provides the fetus with continuous sensory information to adapt to the environment they face once born. This study aimed to assess the chemosensory continuity through a systematic review and meta-analysis of existing evidence on chemosensory continuity from prenatal to first postnatal year. Web of Science Core. Collections, MEDLINE, PsycINFO, EBSCOhost ebook collection was searched from 1900 to 2021. Studies identified from the search were grouped according to type of stimuli the fetuses were exposed to prenatally that the neonatal infants' responses to were being evaluated, namely flavors transferred from the maternal diet, and the odor of their own amniotic fluid. Of the 12 studies that met the eligibility criteria for inclusion (k = 6, k = 6, respectively in the first and the second group of studies), and eight studies (k = 4, k = 4, respectively) provided sufficient data suitable for meta-analysis. Infants, during their first year of life, oriented their heads for significantly longer durations in the direction of the prenatally experienced stimuli with large pooled effect sizes (flavor stimuli, d = 1.24, 95% CI [0.56, 1.91]; amniotic fluid odor, d = 0.853; 95% CI [.632, 1.073]). The pooled effect size for the duration of mouthing behavior was significant in response to prenatal flavor exposure through maternal diet (d = 0.72; 95% CI [0.306, 1.136]), but not for the frequency of negative facial expressions (d = -0.87, 95% CI [-2.39, 0.66]). Postnatal evidence suggests that there is a chemosensory continuity from fetal to the first year of postnatal life.

More than just immaturity: evidence supporting the hypothesis that sleep spindle characteristics reflect GABAergic depolarization in infancy.

Sleep spindles are thalamocortical oscillations with waxing-waning morphology, which comprise the key electroencephalographic (EEG) hallmark of stage 2 non-rapid eye movement sleep. The functional role of sleep spindles is not sufficiently clear, but there is a large body of literature that indicates the relationship between spindle activity and neural plasticity. Many of the spindle parameters (frequency, configuration, duration, density, and topography) vary significantly throughout life. However, the long duration, asynchrony and sharp morphology are the most distinctive characteristics of sleep spindles in infants. This unique infantile phenotype of sleep spindles typically changes after approximately one year of postnatal life in humans. Considering that EEG reflects brain electrochemical activity, there is evidence to suggest that substantial neurochemical events underlie these changes. In this paper, we hypothesize that the GABA (gamma-aminobutyric acid) shift is a key event influencing the sleep spindle phenotype during infancy. We briefly review evidence for the relation between infantile sleep spindles and depolarizing GABA transmission occurring in the developing brain.

Maternal stress effects on infant development in wild Verreaux's sifaka (Propithecus verreauxi)

Maternal effects mediated by nutrients or specific endocrine states of the mother can affect infant development. Specifically, pre- and postnatal maternal stress associated with elevated glucocorticoid (GC) output is known to influence the phenotype of the offspring, including their physical and behavioral development. These developmental processes, however, remain relatively poorly studied in wild vertebrates, including primates with their relatively slow life histories. Here, we investigated the effects of maternal stress, assessed by fecal glucocorticoid output, on infant development in wild Verreaux’s sifakas (Propithecus verreauxi), a group-living Malagasy primate. In a first step, we investigated factors predicting maternal fecal glucocorticoid metabolite (fGCM) concentrations, how they impact infants’ physical and behavioral development during the first 6 months of postnatal life as well as early survival during the first 1.5 years of postnatal life. We collected fecal samples of mothers for hormone assays and behavioral data of 12 infants from two birth cohorts, for which we also assessed growth rates. Maternal fGCM concentrations were higher during the late prenatal but lower during the postnatal period compared to the early/mid prenatal period and were higher during periods of low rainfall. Infants of mothers with higher prenatal fGCM concentrations exhibited faster growth rates and were more explorative in terms of independent foraging and play. Infants of mothers with high pre- and postnatal fGCM concentrations were carried less and spent more time in nipple contact. Time mothers spent carrying infants predicted infant survival: infants that were more carried had lower survival, suggesting that they were likely in poorer condition and had to be cared for longer. Thus, the physical and behavioral development of these young primates were impacted by variation in maternal fGCM concentrations during the first 6 months of their lives, presumably as an adaptive response to living in a highly seasonal, but unpredictable environment.Significance statementThe early development of infants can be impacted by variation in maternal condition. These maternal effects can be mediated by maternal stress (glucocorticoid hormones) and are known to have downstream consequences for behavior, physiology, survival, and reproductive success well into adulthood. However, the direction of the effects of maternal physiological GC output on offspring development is highly variable, even within the same species. We contribute comparative data on maternal stress effects on infant development in a Critically Endangered primate from Madagascar. We describe variation in maternal glucocorticoid output as a function of ecological and reproductive factors and show that patterns of infant growth, behavioral development, and early survival are predicted by maternal glucocorticoids. Our study demonstrates how mothers can influence offspring fitness in response to challenging environmental conditions.

Prospective association of maternal psychosocial stress in pregnancy with newborn hippocampal volume and implications for infant social-emotional development

Maternal psychosocial stress during pregnancy can impact the developing fetal brain and influence offspring mental health. In this context, animal studies have identified the hippocampus and amygdala as key brain regions of interest, however, evidence in humans is sparse. We, therefore, examined the associations between maternal prenatal psychosocial stress, newborn hippocampal and amygdala volumes, and child social-emotional development.In a sample of 86 mother-child dyads, maternal perceived stress was assessed serially in early, mid and late pregnancy. Following birth, newborn (aged 5–64 postnatal days, mean: 25.8 ± 12.9) hippocampal and amygdala volume was assessed using structural magnetic resonance imaging. Infant social-emotional developmental milestones were assessed at 6- and 12-months age using the Bayley-III.After adjusting for covariates, maternal perceived stress during pregnancy was inversely associated with newborn left hippocampal volume (β = −0.26, p = .019), but not with right hippocampal (β = −0.170, p = .121) or bilateral amygdala volumes (ps > .5). Furthermore, newborn left hippocampal volume was positively associated with infant social-emotional development across the first year of postnatal life (B = 0.01, p = .011). Maternal perceived stress was indirectly associated with infant social-emotional development via newborn left hippocampal volume (B = −0.34, 95% CIBC [-0.97, −0.01]), suggesting mediation.This study provides prospective evidence in humans linking maternal psychosocial stress in pregnancy with newborn hippocampal volume and subsequent infant social-emotional development across the first year of life. These findings highlight the importance of maternal psychosocial state during pregnancy as a target amenable to interventions to prevent or attenuate its potentially unfavorable neural and behavioral consequences in the offspring.

A Study on Fetal Intracardiac Echogenic Foci

Objective: The objective of this study is to determine the frequency, location, and delineation of the echogenicity of intracardiac echogenic foci (ICEF) and to ponder the possible etiology of ICEF. Materials and Methods: Retrospective study of 2445 referred cases in second and third trimester for fetal cardiac ultrasound scan from 2010 to 2020, targeted for ruling out congenital heart disease were evaluated and analyzed in detail for ICEF. Further postnatal follow-up was done in 64 cases of ICEF till 7 years of age to see the natural course. Histopathology was performed from one case of fetal autopsy at 19 weeks of gestation for further correlation. Results: Among the fetal cardiac ultrasound cases, 323 (13.2%) showed ICEF (95% confidence interval 11.9–14.6). Majority of these ICEF (96%) were in the left ventricular cavity, and then both ventricles (3%) and remaining in right ventricle and all were located within the papillary muscles. On follow-up of 66 postnatal cases, ICEF had resolved in 97% by 5 years of age. Only two cases reported to have congenital heart disease. No chromosomal anomalies was associated in any case. Histopathology of fetal heart specimen in one case revealed myxomatous degeneration at the apices of the papillary muscle. Conclusion: Frequency of single ICEF is much higher in the left ventricle, and it is invariably located within the upper third of the anterior papillary muscle in such cases. As the gestational age advances, ICEF can resolve in utero, and further complete resolution is seen by 1–7 years of postnatal life. Variability in the echogenicity could be part of transformation of myxomatous tissues to fibrosis or microcalcification. In this study, ICEF have no particular association with congenital heart disease or chromosomal association.

Dynamic changes of high-sensitivity troponin T concentration during infancy: Clinical implications.

Cardiac troponin T determination plays a dominant role in diagnosis of myocardial pathologies. Despite generally accepted use of high-sensitive cardiac troponin T assays (hscTnT) and clearly defined cut-off limit in adults, the uncertainty persists in infants. The aim of this study was to assess plasmatic concentrations of hscTnT and describe sequential age-related dynamic changes of hscTnT in healthy infants and toddlers. Seventy-eight children (52 males/26 females) from Czech Republic aged 44 to 872 days (median, interquartile range 271; 126 to 486 days) were consecutively enrolled in the single-center, prospective observational study. Plasma concentrations of hscTnT were analyzed by the electrochemiluminescent method, age-related reference intervals were calculated using the polynominal regression model. Amongst the study population (n=78), the upper limit of hscTnT concentration defined as the 99th percentile was calculated. The 99th percentile with 95 % confidence interval at the end of 2nd, 3rd, 4th, 5th, 6th and 7th month of postnatal life were: 81 (40.6 to 63.6), 61 (36.0 to 55.3), 47 (31.9 to 48.3), 37 (28.1 to 42.3), 30 (24.7 to 37.2) and 25 (21.5 to 32.7) ng/l, respectively. Concentration of adults 99th percentile (14 ng/l) was achieved approximately at 1 year of postnatal life. Statistically significant negative correlation of hscTnT concentration with age (r=-0.81, p<0.001) was found. Significant gender differences were not found (p>0.07). The study revealed substantially increased reference intervals of hscTnT levels in infants when compared with adult population. Based on our preliminary results, the age-related interpretation of hscTnT plasmatic concentration is recommended.

Fetal and early life exposure to multiple classes of environmental organics measured using teeth

Background: Pediatric tooth biomatrix provides retrospective measurement of early life exposure to environmental contaminants. However, it is still underutilized due to limitations in sample preparation methods. In our previous work, isolated dentin region of the tooth has been used to analyze metal exposure with daily temporal resolution from pre-birth through the first year of postnatal life. We have now extended this technology to quantify pre- and post-natal exposure to organic pollutants.Aim: To develop a robust and sensitive protocol that allows the analysis of temporally-resolved measurements of multiple classes of known environmental organics in teeth.Methods: The analytical method involves the following steps: 1) identifying the temporal zones in dentin to separate pre and post-natal areas; 2) mechanically drilling the areas of interest in dentin; 3) de-calcifying the dried dentin; 4) solvent extraction of the digested dentin; and 5) instrumental analysis using gas chromatography-tandem mass spectrometry (GC-MS/MS). Dentin collected from 60 pediatric teeth were analyzed for persistent and other organic contaminants.Results: More than 100 analytes including polychlorinated biphenyls (PCBs), Polybrominated diphenyls (PBDEs), Organochlorine pesticides (OCPs) and Polyaromatic hydrocarbons (PAHs) were detected in both pre- and post-natal Fractions. Detection rates were &gt; 80% for the majority of the analytes with concentrations up to 200 ng/g of tooth powder. Within each class of chemicals, analytes were highly correlated as observed in other commonly used matrices such as plasma or serum in both pre- and post-natal fractions. Pre- and post-natal analyte concentrations were positively correlated for all classes with higher correlations observed for PCBs and OCPs compared to PBDEs, suggesting differences in sources of exposure.Conclusions: Results of this study indicate that pre- and post-natal dentin fractions from tooth samples can be concurrently analyzed for environmental exposure to multiple classes of organic contaminants thus facilitating broad spectrum retrospective biomonitoring in epidemiological studies.

Development of muscle ultrasound density in healthy fetuses and infants.

Muscle ultrasound density (MUD) is a non-invasive parameter to indicate neuromuscular integrity in both children and adults. In healthy fetuses and infants, physiologic MUD values during development are still lacking. We therefore aimed to determine the physiologic, age-related MUD trend of biceps, quadriceps, tibialis anterior, hamstrings, gluteal and calf muscles, from pre- to the first year of postnatal life. To avoid a bias by pregnancy-related signal disturbances, we expressed fetal MUD as a ratio against bone ultrasound density. We used the full-term prenatal MUD ratio and the newborn postnatal MUD value as reference points, so that MUD development could be quantified from early pre- into postnatal life. Results: During the prenatal period, the total muscle group revealed a developmental MUD trend concerning a fetal increase in MUD-ratio from the 2nd trimester up to the end of the 3rd trimester [median increase: 27% (range 16–45), p < .001]. After birth, MUD-values increased up to the sixth month [median increase: 11% (range -7-27), p = 0.025] and stabilized thereafter. Additionally, there were also individual MUD characteristics per muscle group and developmental stage, such as relatively low MUD values of fetal hamstrings and high values of the paediatric gluteus muscles. These MUD trends are likely to concur with analogous developmentally, maturation-related alterations in the muscle water to peptide content ratios.

Implications of accumulative stress burdens during critical periods of early postnatal life for mortality risk among Guale interred in a colonial era cemetery in Spanish Florida (ca. AD 1605-1680).

Research situated within the Developmental Origins of Health and Disease demonstrates that stressors are correlated with future mortality risk, especially if experienced frequently and during early periods of postnatal life. This study examines if the developmental timing and frequency of early life stressors influenced mortality risk for Indigenous Guale in Spanish Florida during the 17th century. The present study examines internal enamel microgrowth disruptions (accentuated lines-AL) from Guale individuals (n = 52) interred at Mission Santa Catalina de Guale on St. Catherines Island, Georgia (AD 1605-1680). Teeth were thin-sectioned and microscopically analyzed to document AL variables as predictors of age-at-death. Individuals with AL died earlier than those without AL. This difference, however, was not significant. Individuals who exhibit AL formed during their first year of life died on average three times earlier than those who did not. The frequency of AL and age-at-first-AL are significantly correlated with age-at-death, and Cox hazard analyses indicates that individuals with early forming and frequent AL had increased risks of early death. This study emphasizes how the lived experiences of Guale children shaped demographic patterns during the 17th century. The survival of early life stressors resulted in life history trade-offs and increased risks for early death. Mortality risks were exacerbated for individuals who experienced frequent stressors during the earliest periods of life. This underscores a role for bioarchaeology in understanding of how accumulative stress burdens during the earliest years of postnatal life may influence mortality risk.

Divergent neuronal DNA methylation patterns across human cortical development reveal critical periods and a unique role of CpH methylation

BackgroundDNA methylation (DNAm) is a critical regulator of both development and cellular identity and shows unique patterns in neurons. To better characterize maturational changes in DNAm patterns in these cells, we profile the DNAm landscape at single-base resolution across the first two decades of human neocortical development in NeuN+ neurons using whole-genome bisulfite sequencing and compare them to non-neurons (primarily glia) and prenatal homogenate cortex.ResultsWe show that DNAm changes more dramatically during the first 5 years of postnatal life than during the entire remaining period. We further refine global patterns of increasingly divergent neuronal CpG and CpH methylation (mCpG and mCpH) into six developmental trajectories and find that in contrast to genome-wide patterns, neighboring mCpG and mCpH levels within these regions are highly correlated. We integrate paired RNA-seq data and identify putative regulation of hundreds of transcripts and their splicing events exclusively by mCpH levels, independently from mCpG levels, across this period. We finally explore the relationship between DNAm patterns and development of brain-related phenotypes and find enriched heritability for many phenotypes within identified DNAm features.ConclusionsBy profiling DNAm changes in NeuN-sorted neurons over the span of human cortical development, we identify novel, dynamic regions of DNAm that would be masked in homogenate DNAm data; expand on the relationship between CpG methylation, CpH methylation, and gene expression; and find enrichment particularly for neuropsychiatric diseases in genomic regions with cell type-specific, developmentally dynamic DNAm patterns.

Cranial measurements and pattern of head shapes in children (0-36 months) from Sokoto, Nigeria

Purpose: This study investigated the pattern of head shapes in children using cranial index values. Material and Methods: Cranial length, cranial width and cranial index of 210 normal growing children (100 males and 110 females) aged 0 - 36 months old seen at the Institute of Child Health Center, Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria over the period of one year were determined using standard cranial landmarks and procedures. The pattern of head shapes was determined using the cranial index values obtained from the study participants. Results: The overall mean and standard deviation values for cranial length, cranial width and cranial index were 13.79±1.79 cm, 10.95±1.39 cm and 79.49±3.42 respectively. A statistically significant increase was observed in the cranial width values of males when compared to that of females. Meanwhile, there was no statistically significant difference observed in the mean cranial length and mean cranial index values between the sexes. As per the present study, the predominant head shape type in males was Mesocephaly (31.90%) and in females, Brachycephaly (26.19%) while the least observed head shape pattern was Hyperbrachycephaly (1.42%) in males and Dolicocephaly (0.47%) in females. Conclusion: Cranial parameters evaluated in this study are good indicators of skull and brain growth, thus can be of clinical importance in determining the timing and etiology of brain insults, especially in the first three years of postnatal life.

Brain growth in modern humans using multiple developmental databases.

Currently, there are several published articles detailing brain growth in modern humans. The contained databases were derived using disparate methodologies. The objective of the present investigation was to determine the level of agreement among several collections of immature modern human brains. Twenty-one developmental collections of endocranial volume, brain weight, or brain volume were selected for analysis, including one skeletal, six autopsy, and 14 computed tomography/magnetic resonance imaging samples. Step-wise comparisons were determined, using conversion factors for brain specific gravity and size of the subarachnoid space. Derived brain weights are comparable and increase especially during the first year of postnatal life, with a further slight increase (+8-10%) between one and five years, and little change thereafter. The expansion in brain size occurs earlier than body size. Significant sex differences are apparent at all stages of development. Combining all datasets produced a composite database consisting of 3,491 brain weight values, with ages near birth through 18 years. Individual brain weights ranged from 190 to 1,792 g, and mean brain weights ranged from 457 to 1,365 g, with an overall mean and standard deviation of 897 ± 387 g. The investigation compares modern human collections regarding brain size trajectories from birth through 18 years of age. The 21 datasets are then incorporated into a single composite database. All major age groups and both sexes are well represented. The composite database should prove useful to other investigators interested in developmental aspects of the modern human brain.

First-year development of modules and hubs in infant brain functional networks

The human brain develops rapidly in the first postnatal year, in which rewired functional brain networks could shape later behavioral and cognitive performance. Resting-state functional magnetic resonances imaging (rs-fMRI) and complex network analysis have been widely used for characterizing the developmental brain functional connectome. Yet, such studies focusing on the first year of postnatal life are still very limited. Leveraging normally developing longitudinal infant rs-fMRI scans from neonate to one year of age, we investigated how brain functional networks develop at a fine temporal scale (every 3 months). Considering challenges in the infant fMRI-based network analysis, we developed a novel algorithm to construct the robust, temporally consistent and modular structure augmented group-level network based on which functional modules were detected at each age. Our study reveals that the brain functional network is gradually subdivided into an increasing number of functional modules accompanied by the strengthened intra- and inter-modular connectivities. Based on the developing modules, we found connector hubs (the high-centrality regions connecting different modules) emerging and increasing, while provincial hubs (the high-centrality regions connecting regions in the same module) diminishing. Further region-wise longitudinal analysis validates that different hubs have distinct developmental trajectories of the intra- and inter-modular connections suggesting different types of role transitions in network, such as non-hubs to hubs or provincial hubs to connector hubs et al. All findings indicate that functional segregation and integration are both increased in the first year of postnatal life. The module reorganization and hub transition lead to more efficient brain networks, featuring increasingly segregated modular structure and more connector hubs. This study provides the first comprehensive report of the development of functional brain networks at a 3-month interval throughout the first postnatal year of life, which provides essential information to the future neurodevelopmental and developmental disorder studies.

Infant Skin Barrier, Structure, and Enzymatic Activity Differ from Those of Adult in an East Asian Cohort.

Skin physiology is dynamically changing over the first years of postnatal life; however, ethnic variations are still unclear. The aim of this study was to characterize infant skin barrier function, epidermal structure, and desquamation-related enzymatic activity as compared to that of adult skin in an East Asian population. The skin properties of 52 infants (3-24 months) and 27 adults (20-40 years) were assessed by noninvasive methods at the dorsal forearm and upper inner arm. Transepidermal water loss and skin surface conductance values were higher and more dispersed for infants compared to adults. Infant skin surface pH was slightly lower than adult on the dorsal forearm. The infant SC and viable epidermis were thinner compared to adults with differences that were site-specific. Although the chymotrypsin-like activity for infant skin was comparable to adult level, the caseinolytic specific activity was significantly higher for the infant cohort. These observations indicate a differently controlled pattern of corneocyte desquamation in infants. In conclusion, structural and functional differences exist between infant and adult skin in the East Asian population pointing to dynamic maturation of the epidermal barrier early in life.

Fetal Cerebrovascular Maturation: Effects of Hypoxia

The human cerebral vasculature originates in the fourth week of gestation and continues to expand and diversify well into the first few years of postnatal life. A key feature of this growth is smooth muscle differentiation, whereby smooth muscle cells within cerebral arteries transform from migratory to proliferative to synthetic and finally to contractile phenotypes. These phenotypic transformations can be reversed by pathophysiological perturbations such as hypoxia, which causes loss of contractile capacity in immature cerebral arteries. In turn, loss of contractility affects all whole-brain cerebrovascular responses, including those involved in flow-metabolism coupling, vasodilatory responses to acute hypoxia and hypercapnia, cerebral autoregulation, and reactivity to activation of perivascular nerves. Future strategies to minimize cerebral injury following hypoxia-ischemic insults in the immature brain might benefit by targeting treatments to preserve and promote contractile differentiation in the fetal cerebrovasculature. This could potentially be achieved through inhibition of receptor tyrosine kinase-mediated growth factors, such as vascular endothelial growth factor and platelet-derived growth factor, which are mobilized by hypoxic and ischemic injury and which facilitate contractile dedifferentiation. Interruption of the effects of other vascular mitogens, such as endothelin and angiotensin-II, and even some miRNA species, also could be beneficial. Future experimental work that addresses these possibilities offers promise to improve current clinical management of neonates who have suffered and survived hypoxic, ischemic, asphyxic, or inflammatory cerebrovascular insults.