Computational gene expression modeling identifies salivary biomarker analysis that predict oral feeding readiness in the newborn

Validation of Gene Expression Patterns for Oral Feeding Readiness: Transcriptional Analysis of Set of Genes in Neonatal Salivary Samples

BACKGROUND

Neonatal health assessment is crucial for detecting and intervening in various disorders. Traditional gene expression analysis methods often require invasive procedures during sample collection, which may not be feasible or ideal for preterm infants. In recent years, saliva has emerged as a promising noninvasive biofluid for assessing gene expression. Another trend that has been growing is the use of "omics" technologies such as transcriptomics in the analysis of gene expression. The costs for carrying out these analyses and the difficulty of analysis make the detection of candidate genes necessary. These genes act as biomarkers for the maturation stages of the oral feeding issue.

METHODOLOGY

Salivary samples (n = 225) were prospectively collected from 45 preterm (<34 gestational age) infants from five predefined feeding stages and submitted to RT-qPCR. A better description of the targeted genes and results from RT-qPCR analyses were included. The six genes previously identified as predictive of feeding success were tested. The genes are AMPK, FOXP2, WNT3, NPHP4, NPY2R, and PLXNA1, along with two reference genes: GAPDH and 18S. RT-qPCR amplification enabled the analysis of the gene expression of AMPK, FOXP2, WNT3, NPHP4, NPY2R, and PLXNA1 in neonatal saliva. Expression results were correlated with the feeding status during sample collection.

CONCLUSIONS

In summary, the genes AMPK, FOXP2, WNT3, NPHP4, NPY2R, and PLXNA1 play critical roles in regulating oral feeding and the development of premature infants. Understanding the influence of these genes can provide valuable insights for improving nutritional care and support the development of these vulnerable babies. Evidence suggests that saliva-based gene expression analysis in newborns holds great promise for early detection and monitoring of disease and understanding developmental processes. More research and standardization of protocols are needed to fully explore the potential of saliva as a noninvasive biomarker in neonatal care.

Short-Term Outcomes of Early Oral Colostrum Administration in VLBW Neonates: An Open-Label Randomized Controlled Trial

Background

Oropharyngeal colostrum priming (OCP) has been proposed as a potential nutritional option for very low birth weight (VLBW) newborns. This study aimed to determine short-term outcomes of early oral colostrum administration in VLBW neonates.

Methods

This open-label randomized controlled trial was conducted on VLBW neonates admitted to Mahdieh Hospital, Tehran, Iran, between February and December 2022. According to the protocol, all eligible neonates were randomized evenly to the intervention group, which received oral colostrum (OC), and the control group, which received no OC. Finally, short-term outcomes of early OC administration were compared between groups using the independent-samples t test, chi-square, and Fisher exact tests.

Results

Of 80 randomized neonates, 37 and 39 from the intervention and control groups entered the final analysis, respectively. Neonates in the intervention and control groups did not significantly differ in terms of peripherally inserted central catheter (PICC) infection (P = 0.728), sepsis (P = 0.904), necrotizing enterocolitis (NEC) (P > 0.999), intraventricular hemorrhage (IVH) (P = 0.141), retinopathy of prematurity (ROP) (P = 0.923), and bronchopulmonary dysplasia (BPD) (P = 0.633). Furthermore, there was no significant difference between groups considering the time to reach 120 cc/kg feeds (P = 0.557), time to reach birth weight (P = 0.157), length of hospitalization (P = 0.532), and mortality rate (P = 0.628).

Conclusion

The results of our study revealed that despite safety, early OC administration did not improve any of the short-term outcomes in VLBW neonates.

Spectral features of non-nutritive suck dynamics in extremely preterm infants

Background

Non-nutritive suck (NNS) is used to promote ororhythmic patterning and assess oral feeding readiness in preterm infants in the neonatal intensive care unit (NICU). While time domain measures of NNS are available in real time at cribside, our understanding of suck pattern generation in the frequency domain is limited. The aim of this study is to model the development of NNS in the frequency domain using Fourier and machine learning (ML) techniques in extremely preterm infants (EPIs).

Methods

A total of 117 EPIs were randomized to a pulsed or sham orocutaneous intervention during tube feedings 3 times/day for 4 weeks, beginning at 30 weeks post-menstrual age (PMA). Infants were assessed 3 times/week for NNS dynamics until they attained 100% oral feeding or NICU discharge. Digitized NNS signals were processed in the frequency domain using two transforms, including the Welch power spectral density (PSD) method, and the Yule-Walker PSD method. Data analysis proceeded in two stages. Stage 1: ML longitudinal cluster analysis was conducted to identify groups (classes) of infants, each showing a unique pattern of change in Welch and Yule-Walker calculations during the interventions. Stage 2: linear mixed modeling (LMM) was performed for the Welch and Yule-Walker dependent variables to examine the effects of gestationally-aged (GA), PMA, sex (male, female), patient type [respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD)], treatment (NTrainer, Sham), intervention phase [1, 2, 3], cluster class, and phase-by-class interaction.

Results

ML of Welch PSD method and Yule-Walker PSD method measures revealed three membership classes of NNS growth patterns. The dependent measures peak_Hz, PSD amplitude, and area under the curve (AUC) are highly dependent on PMA, but show little relation to respiratory status (RDS, BPD) or somatosensory intervention. Thus, neural regulation of NNS in the frequency domain is significantly different for each identified cluster (classes A, B, C) during this developmental period.

Conclusions

Efforts to increase our knowledge of the evolution of the suck central pattern generator (sCPG) in preterm infants, including NNS rhythmogenesis will help us better understand the observed phenotypes of NNS production in both the frequency and time domains. Knowledge of those features of the NNS which are relatively invariant vs. other features which are modifiable by experience will likewise inform more effective treatment strategies in this fragile population.

Role of forkhead box protein 2 (FOXP2) in oral-motor abilities of preterm infants: A brief literature review

Preterm infants, born before the 37-week gestation period, have limited storage for nutrients at birth and are vulnerable to poor feeding, severe nutritional deficits and growth retardation. The immature gastrointestinal system leads preterm infants to experience a delay in initiating enteral nutrition. Inappropriate feeding can cause acute and long-term morbidity, prolonged hospitalization and increased treatment cost. Generally, preterm infants that are born after 32 weeks of gestation without severe comorbidities do not have dysphagia and should start oral feeding soon after birth. Preterm infants should have well-developed sucking-swallowing-breathing coordination by 32-34 weeks of gestational age. However, some infants take days or weeks to master the skill. The oral feeding development involves forkhead box protein 2 (FOXP2)-expressing neurons that are found in the deep layers of the cortex, basal ganglia, parts of the thalamus and Purkinje cells of the cerebellum. In mammals, these areas belong to the brain network circuits working for motor coordination in learning and acquiring sensorimotor skills. This review aimed to describe the role of FOXP2 in oral-motor skills in preterm infants, including oral feeding, sucking-swallowing-breathing coordination and language development. The oral-motor skills development could be an early predictor for language delay in premature infants, representing a vulnerable group susceptible to such delays.

The effect of oropharyngeal colostrum administration on the clinical outcomes of premature infants: A meta-analysis

BACKGROUND

Preterm complications are now the second leading cause of death in children under five years of age. Colostrum is essential to prevent infection and promote maturation in preterm infants. Guidelines recommend that preterm infants be fed colostrum by the oral and pharyngeal routes as early as possible after birth to provide immune protection; however, due to disease and an uncoordinated sucking and swallowing function, it is challenging to provide colostrum through the oropharyngeal route, which limits the immune protection it provides.

OBJECTIVE

To update the existing meta-analysis, evaluate the effect of oropharyngeal colostrum administration on related outcomes in preterm infants and explore the optimal frequency and duration of oropharyngeal colostrum administration through subgroup analysis.

METHODS

The Cochrane Library, PubMed, Web of Science, ScienceDirect, and Ovid databases were searched for randomized control trials (RCTs) of oropharyngeal colostrum administration for preterm infants. Two researchers screened the literature strictly according to the inclusion and exclusion criteria and evaluated the quality. Primary data and data from the included literature were extracted. Finally, the data were statistically analyzed by the Review Manager 5.3 software.

RESULTS

A total of 1736 preterm infants were included in 16 RCTs. The meta-analysis showed that the incidence of necrotizing enterocolitis, late-onset sepsis, feeding intolerance, and death was lower, the time to full enteral feeding was shorter, and the day of recovery to birth weight was earlier in the intervention group (oropharyngeal colostrum administration group) than in the control group, and this difference was statistically significant. Subgroup analysis: Frequency of oropharyngeal colostrum administration: The incidence of necrotizing enterocolitis and late-onset sepsis in the once every 4 h group was lower than that in the control group, and the time to complete enteral feeding was shorter. Duration of oropharyngeal colostrum administration: In the 1-3 days group and 4-7 days group, the time to full enteral feeding in the intervention group was shorter. In the 8-10 days group, the incidence of necrotizing enterocolitis and late-onset sepsis was lower in the intervention group.

CONCLUSIONS

Oropharyngeal colostrum administration can reduce the incidence of necrotizing enterocolitis, late-onset sepsis, feeding intolerance and mortality, shorten the time to full enteral feeding, and lead to a faster recovery to birth weight in preterm infants. The appropriate oropharyngeal colostrum administration frequency may be 4 h, and the optimal duration may be 8-10 days. Therefore, it is recommended that clinical medical staff implement oropharyngeal colostrum administration for premature infants based on existing evidence.

TWEETABLE ABSTRACT

Oropharyngeal colostrum administration can reduce the incidence of complications in preterm infants and shorten the time to full enteral feeding.

Improve the clinical effective decision of the oral feeding readiness in preterm infants: Revise and validate the TC-POFRAS

BACKGROUND

Currently there is limited information to guide health professionals regarding the optimal time frame to initiate safe and effective oral feedings to preterm infants. The study aims to revise and validate a streamlined version of the Traditional Chinese-Preterm Oral Feeding Readiness Assessment Scale, the TC-POFRAS®, and evaluate its construct validity in the clinical decisions regarding feeding readiness of preterm infants.

METHODS

Eighty-one clinically stable preterm infants were assessed using the TC-POFRAS for oral feeding readiness. Item-total correlation analysis was used to check if any item was inconsistent with the averaged TC-POFRAS scores. Cronbach's α coefficient was used to evaluate the inter-item consistency. Exploratory factor analysis was used to determine the coherence of variables to reorganize assessment domains. The revised version of TC-POFRAS (TC-POFRAS®) was developed and a new cut-off score based on discriminant accuracy was established.

RESULTS

Based on the results from statistical analysis, five items ("lips posture," "tongue posture," "biting reflex," "gag reflex," and "tongue cupping") were deleted from the original TC-POFRAS to form the TC-POFRAS®. The TC-POFRAS®'s global accuracy was 92.1%. The cut-off value of 19 was the one that presented the most optimization of sensitivity based on specificity. The TC-POFRAS® was reconstructed into corrected gestational age and five behavioral domains.

CONCLUSIONS

The TC-POFRAS® is considered a valid, safe, and accurate objective instrument to assist health professionals to initiate oral feeding of preterm infants.

The Utility of Speech-Language Biomarkers to Predict Oral Feeding Outcomes in the Premature Newborn

Purpose Successful oral feeding and speech emergence are dependent upon the coordination of shared oral muscles and facial nerves. We aimed to determine if the speech-associated genes, forkhead box P2 (FOXP2), contactin-associated protein-like 2 (CNTNAP2), glutamate receptor, ionotropic, N-methyl D-aspartate 2A (GRIN2A), and neurexin 1, were detectable in neonatal saliva and could predict feeding outcomes in premature newborns. Method In this prospective, observational, preliminary study, saliva collected from 51 premature infants (gestational ages: 30-34 6/7 weeks) at different stages of oral feeding development underwent gene expression analysis. Binary (+/-) expression profiles were explored and examined in relation to days to achieve full oral feeds. Results GRIN2A and neurexin 1 rarely amplified in neonatal saliva and were not informative. Infants who amplified FOXP2 but not CNTNAP2 at the start of oral feeds achieved oral feeding success 3.20 (95% CI [-2.5, 8.9]) days sooner than other gene combinations. Conclusions FOXP2 and CNTNAP2 may be informative in predicting oral feeding outcomes in newborns. Salivary analysis at the start of oral feeding trials may inform feeding outcomes in this population and warrants further investigation.

Technical Considerations and Protocol Optimization for Neonatal Salivary Biomarker Discovery and Analysis

Non-invasive techniques to monitor and diagnose neonates, particularly those born prematurely, are a long-sought out goal of Newborn Medicine. In recent years, technical advances, combined with increased assay sensitivity, have permitted the high-throughput analysis of multiple biomarkers simultaneously from a single sample source. Multiplexed transcriptomic and proteomic platforms, along with more comprehensive assays such as RNASeq, allow for interrogation of ongoing physiology and pathology in unprecedented ways. In the fragile neonatal population, saliva is an ideal biofluid to assess clinical status serially and offers many advantages over more invasively obtained blood samples. Importantly, saliva samples are amenable to analysis on emerging proteomic and transcriptomic platforms, even at quantitatively limited volumes. However, biomarker targets are often degraded in human saliva, and as a mixed source biofluid containing both human and microbial targets, saliva presents unique challenges for the investigator. Here, we provide insight into technical considerations and protocol optimizations developed in our laboratory to quantify and discover neonatal salivary biomarkers with improved reproducibility and reliability. We will detail insights learned from years of experimentation on neonatal saliva within our laboratory ranging from salivary collection techniques to processing to downstream analyses, highlighting the need for consistency in approach and a global understanding of both the potential benefits and limitations of neonatal salivary biomarker analyses. Importantly, we will highlight the need for robust and stringent research in this population to provide the field with standardized approaches and workflows to impact neonatal care successfully.

Optimal Timing to Utilize Olfactory Stimulation with Maternal Breast Milk to Improve Oral Feeding Skills in the Premature Newborn

Background: Olfactory maturation is essential for successful oral feeding. Previous studies have suggested that olfactory stimulation with maternal breast milk may expedite oral feeding skills in the premature infant; however, the optimal developmental window to utilize this intervention and sex-specific responses to stimuli are largely unknown. Objectives: To determine individual responses to olfactory stimulation with mother's own milk (MOM) on feeding outcomes in premature newborns. Materials and Methods: Infants born between 28 0/7 and 33 6/7 weeks' gestation (n = 36) were randomized to receive either MOM or water (sham) stimulus during the learning process of oral feeding. Clinical and feeding outcomes were recorded. Statistical analyses examined the effect of stimulation with MOM on feeding outcomes stratified for age and sex. Results: Overall, there was no significant difference between sham infants compared with MOM infants in mean postmenstrual age of full oral feeds (sham: 35 5/7 versus MOM 36 0/7; p = 0.37). However, when stratified by gestational age (GA), infants born <31 weeks' gestation who received MOM stimulation learned to feed sooner than controls (p = 0.06), whereas infants born ≥31 weeks' gestation learned to feed later than controls (p = 0.20) with a significant interaction (p = 0.02) between the stimulus (MOM versus sham) and dichotomized GA (<31 versus ≥31 weeks). There were no sex differences in response to olfactory stimulus. Conclusions: Infants born <31 weeks' GA who received MOM stimulation learned to feed sooner than control infants and the impact of MOM is significantly different between infants born before or after 31 weeks GA. These data suggest there may be an optimal time in development to utilize maternal breast milk to expedite oral feeding maturation in the premature newborn.

Oral Feeding Success: A Concept Analysis

BACKGROUND

The term "oral feeding success" (OFS) is frequently used in clinical practice and research. However, OFS is inconsistently defined, which impacts the ability to adequately evaluate OFS, identify risk factors, and implement interventions in clinical practice and research.

PURPOSE

To develop the defining attributes, antecedents, and consequences for the concept of OFS in preterm infants during their initial hospitalization.

METHODS

PubMed, CINAHL, and PsycINFO databases were searched for English articles containing the key words "oral feeding success" and "preterm infants." The Walker and Avant method for concept analysis was employed.

RESULTS

Sixteen articles revealed the defining attributes, antecedents, and consequences. Defining attributes included (1) physiologic stability; (2) full oral feeding; and (3) combined criteria of feeding proficiency (≥30% of the prescribed volume during the first 5 minutes), feeding efficiency (≥1.5 mL/min over the entire feeding), and intake quantity (≥80% of the prescribed volume).

IMPLICATIONS FOR PRACTICE

The 3 defining attributes may be used in clinical practice to consistently evaluate OFS. The antecedents of OFS provide clinicians with a frame of reference to assess oral feeding readiness, identify risk factors, and implement effective interventions. The consequences of OFS allow clinicians to anticipate challenges when OFS is not achieved and create a care plan to support the infants.

IMPLICATIONS FOR RESEARCH

The empirical referents of OFS provide consistent and clear operational definitions of OFS for use in research. The antecedents and consequences may guide researchers to select specific measures or covariates to evaluate valid measures of OFS.

Optimal reference genes for RT-qPCR normalization in the newborn

It is difficult to identify reliable reference genes for transcriptomic analyses in biofluids such as saliva. This situation is particularly relevant for the newborn population, where rapid development is associated with dynamic changes in gene expression. Real-time gene expression monitoring holds great promise for elucidating disrupted pathways that result in morbidities unique to this population, such as retinopathy of prematurity, but its impact depends on identifying stable and consistently expressed genes across a wide range of gestational ages. We extracted total RNA from 400 neonatal saliva samples (postconceptional ages: 32 5/7 to 48 2/7 weeks), converted it to cDNA, and pre-amplified and analyzed it by qPCR for three commonly used reference genes, ACTB, GAPDH, and YWHAZ. Relative quantification was determined using the Δ Ct method. Data were analyzed as a whole and also stratified by age and sex. Descriptive statistics and homogeneity of variance were performed to identify optimal reference genes. Data analyzed from all ages and both sexes showed significant expression variation for ACTB, while GAPDH and YWHAZ showed greater stability. Male infants exhibited increased expression variation compared to females for ACTB, but neither GAPDH nor YWHAZ showed significant variance for either sex. We suggest that ACTB is an unreliable reference gene for the newborn population. Males showed significantly more variation in ACTB expression compared to females, which suggests a sex-specific developmental role for this biomarker. By contrast, GAPDH and YWHAZ were less variable and therefore preferable for use in neonates. Our findings may improve the use of reference genes for the RT-qPCR platform in the newborn over a wide range of gestational ages, thereby minimizing the likelihood of erroneous interpretation of gene expression during rapid growth, development, and differentiation.

Somatosensory Modulation of Salivary Gene Expression and Oral Feeding in Preterm Infants: Randomized Controlled Trial

BACKGROUND

Despite numerous medical advances in the care of at-risk preterm neonates, oral feeding still represents one of the first and most advanced neurological challenges facing this delicate population. Objective, quantitative, and noninvasive assessment tools, as well as neurotherapeutic strategies, are greatly needed in order to improve feeding and developmental outcomes. Pulsed pneumatic orocutaneous stimulation has been shown to improve nonnutritive sucking (NNS) skills in preterm infants who exhibit delayed or disordered nipple feeding behaviors. Separately, the study of the salivary transcriptome in neonates has helped identify biomarkers directly linked to successful neonatal oral feeding behavior. The combination of noninvasive treatment strategies and transcriptomic analysis represents an integrative approach to oral feeding in which rapid technological advances and personalized transcriptomics can safely and noninvasively be brought to the bedside to inform medical care decisions and improve care and outcomes.

OBJECTIVE

The study aimed to conduct a multicenter randomized control trial (RCT) to combine molecular and behavioral methods in an experimental conceptualization approach to map the effects of PULSED somatosensory stimulation on salivary gene expression in the context of the acquisition of oral feeding habits in high-risk human neonates. The aims of this study represent the first attempt to combine noninvasive treatment strategies and transcriptomic assessments of high-risk extremely preterm infants (EPI) to (1) improve oral feeding behavior and skills, (2) further our understanding of the gene ontology of biologically diverse pathways related to oral feeding, (3) use gene expression data to personalize neonatal care and individualize treatment strategies and timing interventions, and (4) improve long-term developmental outcomes.

METHODS

A total of 180 extremely preterm infants from three neonatal intensive care units (NICUs) will be randomized to receive either PULSED or SHAM (non-pulsing) orocutaneous intervention simultaneous with tube feedings 3 times per day for 4 weeks, beginning at 30 weeks postconceptional age. Infants will also be assessed 3 times per week for NNS performance, and multiple saliva samples will be obtained each week for transcriptomic analysis, until infants have achieved full oral feeding status. At 18 months corrected age (CA), infants will undergo neurodevelopmental follow-up testing, the results of which will be correlated with feeding outcomes in the neo-and post-natal period and with gene expression data and intervention status.

RESULTS

The ongoing National Institutes of Health funded randomized controlled trial R01HD086088 is actively recruiting participants. The expected completion date of the study is 2021.

CONCLUSIONS

Differential salivary gene expression profiles in response to orosensory entrainment intervention are expected to lead to the development of individualized interventions for the diagnosis and management of oral feeding in preterm infants.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02696343; https://clinicaltrials.gov/ct2/show/NCT02696343 (Archived by WebCite at http://www.webcitation.org/6r5NbJ9Ym).

Salivary Diagnostics in Pediatrics: Applicability, Translatability, and Limitations

In the last decade, technological advances, combined with an improved appreciation of the ability of saliva to inform caregivers about both oral health and systemic disease, have led to the emergence of salivary diagnostic platforms. However, the majority of these assays have targeted diseases that more commonly affect the adult population, largely neglecting infants and children who arguably could benefit the most from non-invasive assessment tools for health monitoring. Gaining access into development, infection, and disease through comprehensive "omic" analyses of saliva could significantly improve care and enhance health access. In this review, we will highlight novel applications of salivary diagnostics in pediatrics across the "omic" spectrum, including at the genomic, transcriptomic, proteomic, microbiomic, and metabolomic level. The challenges to implementing salivary platforms into care, including the effects of age, diet, and developmental stage on salivary components, will be reviewed. Ultimately, large-scale, multicenter trials must be performed to establish normative biomarker values across the age spectrum to accurately discriminate between health and disease. Only then can salivary diagnostics truly translate into pediatric care.

Development of a Rapid Salivary Proteomic Platform for Oral Feeding Readiness in the Preterm Newborn

Oral feeding competency is a major determinant of length of stay in the neonatal intensive care unit. An infant must be able to consistently demonstrate the ability to take all required enteral nutrition by mouth before discharge home. Most infants born prematurely (<37 weeks) will require days, if not weeks, to master this oral feeding competency skill. Inappropriately timed feeding attempts can lead to acute and long-term morbidities, prolonged hospitalizations, and increased health-care costs. Previously, a panel of five genes involved in essential developmental pathways including sensory integration (nephronophthisis 4, Plexin A1), hunger signaling [neuropeptide Y2 receptor (NPY2R), adenosine-monophosphate-activated protein kinase (AMPK)], and facial development (wingless-type MMTV integration site family, member 3) required for oral feeding success were identified in neonatal saliva. This study aimed to translate these five transcriptomic biomarkers into a rapid proteomic platform to provide objective, real-time assessment of oral feeding skills, to better inform care, and to improve neonatal outcomes. Total protein was extracted from saliva of 10 feeding-successful and 10 feeding-unsuccessful infants matched for age, sex, and post-conceptional age. Development of immunoassays was attempted for five oral feeding biomarkers and two reference biomarkers (GAPDH and YWHAZ) to normalize for starting protein concentrations. Normalized protein concentrations were correlated to both feeding status at time of sample collection and previously described gene expression profiles. Only the reference proteins and those involved in hunger signaling were detected in neonatal saliva at measurable levels. Expression patterns for NPY2R and AMPK correlated with the gene expression patterns previously seen between successful and unsuccessful feeders and predicted feeding outcome. Salivary proteins associated with hunger signaling are readily quantifiable in neonatal saliva and may be utilized to assess oral feeding readiness in the newborn. This study lays the foundation for the development of an informative, rapid, proteomic platform to assess neonatal oral feeding maturation.

Oral colostrum priming shortens hospitalization without changing the immunomicrobial milieu

OBJECTIVE

Oral colostrum priming (OCP) after birth in preterm infants is associated with improved weight gain and modification of the oral immunomicrobial environment. We hypothesized that OCP would modify salivary immune peptides and the oral microbiota in preterm infants.

STUDY DESIGN

We conducted a prospective, randomized clinical trial to determine the effects of OCP on salivary immune peptide representation in preterm infants (<32 weeks completed gestation at birth). Saliva samples were collected before and after OCP. Salivary immune peptide representation was determined via mass spectroscopy. Oral microbiota representation was determined via sequencing of the 16S rRNA gene.

RESULTS

Neonates who received OCP (n=48) had a 16-day reduction in the median length of hospitalization as compared with infants who did not receive OCP (n=51). No differences in salivary immune peptide sequence representation before OCP between groups were found. Longitudinal changes in peptides were detected (lysozyme C, immunoglobulin A, lactoferrin) but were limited to a single peptide difference (α-defensin 1) between primed and unprimed infants after OCP. We found no difference in microbial diversity between treatment groups at any time point, but diversity decreased significantly over time in both groups. OCP treatment marginally modified oral taxa with a decline in abundance of Streptococci in the OCP group at 30 days of life.

CONCLUSIONS

OCP had neither an effect on the salivary peptides we examined nor on overall oral bacterial diversity and composition. Infants who received OCP had a reduced length of hospitalization and warrants further investigation.

FOXP2 gene deletion and infant feeding difficulties: a case report

Forkhead box protein P2 (FOXP2) is a well-studied gene known to play an essential role in normal speech development. Deletions in the gene have been shown to result in developmental speech disorders and regulatory disruption of downstream gene targets associated with common forms of language impairments. Despite similarities in motor planning and execution between speech development and oral feeding competence, there have been no reports to date linking deletions within the FOXP2 gene to oral feeding impairments in the newborn. The patient was a nondysmorphic, appropriately and symmetrically grown male infant born at 35-wk gestational age. He had a prolonged neonatal intensive care unit stay because of persistent oral feeding incoordination requiring gastrostomy tube placement. Cardiac and neurological imagings were within normal limits. A microarray analysis found an ∼9-kb loss within chromosome band 7q3.1 that contains exon 2 of FOXP2, demonstrating a single copy of this region instead of the normal two copies per diploid gene. This case study expands our current understanding of the role FOXP2 exerts on motor planning and coordination necessary for both oral feeding success and speech–language development. This case report has important consequences for future diagnosis and treatment for infants with FOXP2 deletions, mutations, and varying levels of gene expression.

Salivary FOXP2 expression and oral feeding success in premature infants

The objective of the study is to determine whether salivary FOXP2 gene expression levels at the initiation of oral feeding attempts are predictive of oral feeding success in the premature newborn. In this prospective study, saliva samples from 21 premature infants (13 males; birth gestational age [GA]: 30–34 wk) were collected around the initiation of oral feeding trials. Total RNA was extracted and underwent reverse transcription-quantitative polymerase chain reaction amplification for FOXP2. Oral feeding success was denoted by the days required to attain full oral feeds. A linear regression model, controlling for sex, birth GA, and weight at salivary collection, revealed that FOXP2 expression was significantly associated with oral feeding success (P = 0.002). The higher the expression level of FOXP2, the shorter the duration to feed. Salivary FOXP2 expression levels are significantly associated with oral feeding success in the preterm infant. FOXP2 may serve as a novel and informative biomarker to noninvasively assess infant feeding skills to reduce morbidities and length of stay.

The Neonatal Salivary Transcriptome

The ability to noninvasively assess the physical and developmental status of a neonate is a goal of modern medicine. In recent years, technological advances have permitted the high-throughput analysis of saliva for thousands of genes, proteins, and metabolites from a single sample source. Saliva is an ideal biofluid to assess health, disease, and development in the newborn. It may be harnessed repeatedly, even in the most vulnerable patients, without risk of harm. Translating novel information about an infant's global development and risk of disease to the neonatal bedside through the salivary transcriptome has the potential to significantly improve clinical care and outcomes in this at-risk population.